2 * SPDX-License-Identifier: BSD-2-Clause
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Copyright 2012 John Marino <draco@marino.st>.
8 * Copyright 2014-2017 The FreeBSD Foundation
11 * Portions of this software were developed by Konstantin Belousov
12 * under sponsorship from the FreeBSD Foundation.
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 * Dynamic linker for ELF.
38 * John Polstra <jdp@polstra.com>.
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
44 #include <sys/param.h>
45 #include <sys/mount.h>
48 #include <sys/sysctl.h>
50 #include <sys/utsname.h>
51 #include <sys/ktrace.h>
66 #include "rtld_paths.h"
68 #include "rtld_printf.h"
69 #include "rtld_malloc.h"
70 #include "rtld_utrace.h"
72 #include "rtld_libc.h"
75 typedef void (*func_ptr_type)(void);
76 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
79 /* Variables that cannot be static: */
80 extern struct r_debug r_debug; /* For GDB */
81 extern int _thread_autoinit_dummy_decl;
82 extern void (*__cleanup)(void);
90 * Function declarations.
92 static const char *basename(const char *);
93 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
94 const Elf_Dyn **, const Elf_Dyn **);
95 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
97 static bool digest_dynamic(Obj_Entry *, int);
98 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
99 static void distribute_static_tls(Objlist *, RtldLockState *);
100 static Obj_Entry *dlcheck(void *);
101 static int dlclose_locked(void *, RtldLockState *);
102 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
103 int lo_flags, int mode, RtldLockState *lockstate);
104 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
105 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
106 static bool donelist_check(DoneList *, const Obj_Entry *);
107 static void dump_auxv(Elf_Auxinfo **aux_info);
108 static void errmsg_restore(struct dlerror_save *);
109 static struct dlerror_save *errmsg_save(void);
110 static void *fill_search_info(const char *, size_t, void *);
111 static char *find_library(const char *, const Obj_Entry *, int *);
112 static const char *gethints(bool);
113 static void hold_object(Obj_Entry *);
114 static void unhold_object(Obj_Entry *);
115 static void init_dag(Obj_Entry *);
116 static void init_marker(Obj_Entry *);
117 static void init_pagesizes(Elf_Auxinfo **aux_info);
118 static void init_rtld(caddr_t, Elf_Auxinfo **);
119 static void initlist_add_neededs(Needed_Entry *, Objlist *);
120 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
121 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
122 static void linkmap_add(Obj_Entry *);
123 static void linkmap_delete(Obj_Entry *);
124 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
125 static void unload_filtees(Obj_Entry *, RtldLockState *);
126 static int load_needed_objects(Obj_Entry *, int);
127 static int load_preload_objects(const char *, bool);
128 static int load_kpreload(const void *addr);
129 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
130 static void map_stacks_exec(RtldLockState *);
131 static int obj_disable_relro(Obj_Entry *);
132 static int obj_enforce_relro(Obj_Entry *);
133 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
134 static void objlist_call_init(Objlist *, RtldLockState *);
135 static void objlist_clear(Objlist *);
136 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
137 static void objlist_init(Objlist *);
138 static void objlist_push_head(Objlist *, Obj_Entry *);
139 static void objlist_push_tail(Objlist *, Obj_Entry *);
140 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
141 static void objlist_remove(Objlist *, Obj_Entry *);
142 static int open_binary_fd(const char *argv0, bool search_in_path,
143 const char **binpath_res);
144 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
145 const char **argv0, bool *dir_ignore);
146 static int parse_integer(const char *);
147 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
148 static void print_usage(const char *argv0);
149 static void release_object(Obj_Entry *);
150 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
151 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
152 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
153 int flags, RtldLockState *lockstate);
154 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
156 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
157 static int rtld_dirname(const char *, char *);
158 static int rtld_dirname_abs(const char *, char *);
159 static void *rtld_dlopen(const char *name, int fd, int mode);
160 static void rtld_exit(void);
161 static void rtld_nop_exit(void);
162 static char *search_library_path(const char *, const char *, const char *,
164 static char *search_library_pathfds(const char *, const char *, int *);
165 static const void **get_program_var_addr(const char *, RtldLockState *);
166 static void set_program_var(const char *, const void *);
167 static int symlook_default(SymLook *, const Obj_Entry *refobj);
168 static int symlook_global(SymLook *, DoneList *);
169 static void symlook_init_from_req(SymLook *, const SymLook *);
170 static int symlook_list(SymLook *, const Objlist *, DoneList *);
171 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
172 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
173 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
174 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline;
175 static void trace_loaded_objects(Obj_Entry *, bool);
176 static void unlink_object(Obj_Entry *);
177 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
178 static void unref_dag(Obj_Entry *);
179 static void ref_dag(Obj_Entry *);
180 static char *origin_subst_one(Obj_Entry *, char *, const char *,
182 static char *origin_subst(Obj_Entry *, const char *);
183 static bool obj_resolve_origin(Obj_Entry *obj);
184 static void preinit_main(void);
185 static int rtld_verify_versions(const Objlist *);
186 static int rtld_verify_object_versions(Obj_Entry *);
187 static void object_add_name(Obj_Entry *, const char *);
188 static int object_match_name(const Obj_Entry *, const char *);
189 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
190 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
191 struct dl_phdr_info *phdr_info);
192 static uint32_t gnu_hash(const char *);
193 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
194 const unsigned long);
196 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
197 void _r_debug_postinit(struct link_map *) __noinline __exported;
199 int __sys_openat(int, const char *, int, ...);
204 struct r_debug r_debug __exported; /* for GDB; */
205 static bool libmap_disable; /* Disable libmap */
206 static bool ld_loadfltr; /* Immediate filters processing */
207 static const char *libmap_override;/* Maps to use in addition to libmap.conf */
208 static bool trust; /* False for setuid and setgid programs */
209 static bool dangerous_ld_env; /* True if environment variables have been
210 used to affect the libraries loaded */
211 bool ld_bind_not; /* Disable PLT update */
212 static const char *ld_bind_now; /* Environment variable for immediate binding */
213 static const char *ld_debug; /* Environment variable for debugging */
214 static bool ld_dynamic_weak = true; /* True if non-weak definition overrides
216 static const char *ld_library_path;/* Environment variable for search path */
217 static const char *ld_library_dirs;/* Environment variable for library descriptors */
218 static const char *ld_preload; /* Environment variable for libraries to
220 static const char *ld_preload_fds;/* Environment variable for libraries represented by
222 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
223 static const char *ld_tracing; /* Called from ldd to print libs */
224 static const char *ld_utrace; /* Use utrace() to log events. */
225 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
226 static Obj_Entry *obj_main; /* The main program shared object */
227 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
228 static unsigned int obj_count; /* Number of objects in obj_list */
229 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
231 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
232 STAILQ_HEAD_INITIALIZER(list_global);
233 static Objlist list_main = /* Objects loaded at program startup */
234 STAILQ_HEAD_INITIALIZER(list_main);
235 static Objlist list_fini = /* Objects needing fini() calls */
236 STAILQ_HEAD_INITIALIZER(list_fini);
238 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
240 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
242 extern Elf_Dyn _DYNAMIC;
243 #pragma weak _DYNAMIC
245 int dlclose(void *) __exported;
246 char *dlerror(void) __exported;
247 void *dlopen(const char *, int) __exported;
248 void *fdlopen(int, int) __exported;
249 void *dlsym(void *, const char *) __exported;
250 dlfunc_t dlfunc(void *, const char *) __exported;
251 void *dlvsym(void *, const char *, const char *) __exported;
252 int dladdr(const void *, Dl_info *) __exported;
253 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
254 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
255 int dlinfo(void *, int , void *) __exported;
256 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
257 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
258 int _rtld_get_stack_prot(void) __exported;
259 int _rtld_is_dlopened(void *) __exported;
260 void _rtld_error(const char *, ...) __exported;
262 /* Only here to fix -Wmissing-prototypes warnings */
263 int __getosreldate(void);
264 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
265 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
268 static int osreldate;
272 static int stack_prot = PROT_READ | PROT_WRITE | PROT_EXEC;
273 static int max_stack_flags;
276 * Global declarations normally provided by crt1. The dynamic linker is
277 * not built with crt1, so we have to provide them ourselves.
283 * Used to pass argc, argv to init functions.
289 * Globals to control TLS allocation.
291 size_t tls_last_offset; /* Static TLS offset of last module */
292 size_t tls_last_size; /* Static TLS size of last module */
293 size_t tls_static_space; /* Static TLS space allocated */
294 static size_t tls_static_max_align;
295 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
296 int tls_max_index = 1; /* Largest module index allocated */
298 static bool ld_library_path_rpath = false;
299 bool ld_fast_sigblock = false;
302 * Globals for path names, and such
304 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
305 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
306 const char *ld_path_rtld = _PATH_RTLD;
307 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
308 const char *ld_env_prefix = LD_;
310 static void (*rtld_exit_ptr)(void);
313 * Fill in a DoneList with an allocation large enough to hold all of
314 * the currently-loaded objects. Keep this as a macro since it calls
315 * alloca and we want that to occur within the scope of the caller.
317 #define donelist_init(dlp) \
318 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
319 assert((dlp)->objs != NULL), \
320 (dlp)->num_alloc = obj_count, \
323 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
324 if (ld_utrace != NULL) \
325 ld_utrace_log(e, h, mb, ms, r, n); \
329 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
330 int refcnt, const char *name)
332 struct utrace_rtld ut;
333 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
335 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
338 ut.mapbase = mapbase;
339 ut.mapsize = mapsize;
341 bzero(ut.name, sizeof(ut.name));
343 strlcpy(ut.name, name, sizeof(ut.name));
344 utrace(&ut, sizeof(ut));
358 LD_LIBRARY_PATH_RPATH,
361 LD_TRACE_LOADED_OBJECTS,
365 LD_TRACE_LOADED_OBJECTS_PROGNAME,
366 LD_TRACE_LOADED_OBJECTS_FMT1,
367 LD_TRACE_LOADED_OBJECTS_FMT2,
368 LD_TRACE_LOADED_OBJECTS_ALL,
372 struct ld_env_var_desc {
373 const char * const n;
377 #define LD_ENV_DESC(var, unsec) \
378 [LD_##var] = { .n = #var, .unsecure = unsec }
380 static struct ld_env_var_desc ld_env_vars[] = {
381 LD_ENV_DESC(BIND_NOW, false),
382 LD_ENV_DESC(PRELOAD, true),
383 LD_ENV_DESC(LIBMAP, true),
384 LD_ENV_DESC(LIBRARY_PATH, true),
385 LD_ENV_DESC(LIBRARY_PATH_FDS, true),
386 LD_ENV_DESC(LIBMAP_DISABLE, true),
387 LD_ENV_DESC(BIND_NOT, true),
388 LD_ENV_DESC(DEBUG, true),
389 LD_ENV_DESC(ELF_HINTS_PATH, true),
390 LD_ENV_DESC(LOADFLTR, true),
391 LD_ENV_DESC(LIBRARY_PATH_RPATH, true),
392 LD_ENV_DESC(PRELOAD_FDS, true),
393 LD_ENV_DESC(DYNAMIC_WEAK, true),
394 LD_ENV_DESC(TRACE_LOADED_OBJECTS, false),
395 LD_ENV_DESC(UTRACE, false),
396 LD_ENV_DESC(DUMP_REL_PRE, false),
397 LD_ENV_DESC(DUMP_REL_POST, false),
398 LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false),
399 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false),
400 LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false),
401 LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false),
402 LD_ENV_DESC(SHOW_AUXV, false),
406 ld_get_env_var(int idx)
408 return (ld_env_vars[idx].val);
412 rtld_get_env_val(char **env, const char *name, size_t name_len)
416 for (m = env; *m != NULL; m++) {
420 /* corrupt environment? */
423 if (v - n == (ptrdiff_t)name_len &&
424 strncmp(name, n, name_len) == 0)
431 rtld_init_env_vars_for_prefix(char **env, const char *env_prefix)
433 struct ld_env_var_desc *lvd;
434 size_t prefix_len, nlen;
438 prefix_len = strlen(env_prefix);
439 for (m = env; *m != NULL; m++) {
441 if (strncmp(env_prefix, n, prefix_len) != 0) {
442 /* Not a rtld environment variable. */
448 /* corrupt environment? */
451 for (i = 0; i < (int)nitems(ld_env_vars); i++) {
452 lvd = &ld_env_vars[i];
453 if (lvd->val != NULL) {
454 /* Saw higher-priority variable name already. */
457 nlen = strlen(lvd->n);
458 if (v - n == (ptrdiff_t)nlen &&
459 strncmp(lvd->n, n, nlen) == 0) {
468 rtld_init_env_vars(char **env)
470 rtld_init_env_vars_for_prefix(env, ld_env_prefix);
474 set_ld_elf_hints_path(void)
476 if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0)
477 ld_elf_hints_path = ld_elf_hints_default;
481 rtld_round_page(uintptr_t x)
483 return (roundup2(x, page_size));
487 rtld_trunc_page(uintptr_t x)
489 return (rounddown2(x, page_size));
493 * Main entry point for dynamic linking. The first argument is the
494 * stack pointer. The stack is expected to be laid out as described
495 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
496 * Specifically, the stack pointer points to a word containing
497 * ARGC. Following that in the stack is a null-terminated sequence
498 * of pointers to argument strings. Then comes a null-terminated
499 * sequence of pointers to environment strings. Finally, there is a
500 * sequence of "auxiliary vector" entries.
502 * The second argument points to a place to store the dynamic linker's
503 * exit procedure pointer and the third to a place to store the main
506 * The return value is the main program's entry point.
509 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
511 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
512 Objlist_Entry *entry;
513 Obj_Entry *last_interposer, *obj, *preload_tail;
514 const Elf_Phdr *phdr;
516 RtldLockState lockstate;
519 char **argv, **env, **envp, *kexecpath;
520 const char *argv0, *binpath, *library_path_rpath;
521 struct ld_env_var_desc *lvd;
523 char buf[MAXPATHLEN];
524 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc;
527 int old_auxv_format = 1;
529 bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path;
532 * On entry, the dynamic linker itself has not been relocated yet.
533 * Be very careful not to reference any global data until after
534 * init_rtld has returned. It is OK to reference file-scope statics
535 * and string constants, and to call static and global functions.
538 /* Find the auxiliary vector on the stack. */
542 sp += argc + 1; /* Skip over arguments and NULL terminator */
544 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
546 aux = (Elf_Auxinfo *) sp;
548 /* Digest the auxiliary vector. */
549 for (i = 0; i < AT_COUNT; i++)
551 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
552 if (auxp->a_type < AT_COUNT)
553 aux_info[auxp->a_type] = auxp;
555 if (auxp->a_type == 23) /* AT_STACKPROT */
561 if (old_auxv_format) {
562 /* Remap from old-style auxv numbers. */
563 aux_info[23] = aux_info[21]; /* AT_STACKPROT */
564 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */
565 aux_info[19] = aux_info[17]; /* AT_NCPUS */
566 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */
567 aux_info[15] = aux_info[13]; /* AT_EXECPATH */
568 aux_info[13] = NULL; /* AT_GID */
570 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */
571 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */
572 aux_info[16] = aux_info[14]; /* AT_CANARY */
573 aux_info[14] = NULL; /* AT_EGID */
577 /* Initialize and relocate ourselves. */
578 assert(aux_info[AT_BASE] != NULL);
579 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
583 __progname = obj_rtld.path;
584 argv0 = argv[0] != NULL ? argv[0] : "(null)";
589 if (aux_info[AT_BSDFLAGS] != NULL &&
590 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0)
591 ld_fast_sigblock = true;
593 trust = !issetugid();
596 md_abi_variant_hook(aux_info);
597 rtld_init_env_vars(env);
600 if (aux_info[AT_EXECFD] != NULL) {
601 fd = aux_info[AT_EXECFD]->a_un.a_val;
603 assert(aux_info[AT_PHDR] != NULL);
604 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
605 if (phdr == obj_rtld.phdr) {
607 _rtld_error("Tainted process refusing to run binary %s",
613 dbg("opening main program in direct exec mode");
615 rtld_argc = parse_args(argv, argc, &search_in_path, &fd,
616 &argv0, &dir_ignore);
617 explicit_fd = (fd != -1);
620 fd = open_binary_fd(argv0, search_in_path, &binpath);
621 if (fstat(fd, &st) == -1) {
622 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
623 explicit_fd ? "user-provided descriptor" : argv0,
624 rtld_strerror(errno));
629 * Rough emulation of the permission checks done by
630 * execve(2), only Unix DACs are checked, ACLs are
631 * ignored. Preserve the semantic of disabling owner
632 * to execute if owner x bit is cleared, even if
633 * others x bit is enabled.
634 * mmap(2) does not allow to mmap with PROT_EXEC if
635 * binary' file comes from noexec mount. We cannot
636 * set a text reference on the binary.
639 if (st.st_uid == geteuid()) {
640 if ((st.st_mode & S_IXUSR) != 0)
642 } else if (st.st_gid == getegid()) {
643 if ((st.st_mode & S_IXGRP) != 0)
645 } else if ((st.st_mode & S_IXOTH) != 0) {
648 if (!dir_enable && !dir_ignore) {
649 _rtld_error("No execute permission for binary %s",
655 * For direct exec mode, argv[0] is the interpreter
656 * name, we must remove it and shift arguments left
657 * before invoking binary main. Since stack layout
658 * places environment pointers and aux vectors right
659 * after the terminating NULL, we must shift
660 * environment and aux as well.
662 main_argc = argc - rtld_argc;
663 for (i = 0; i <= main_argc; i++)
664 argv[i] = argv[i + rtld_argc];
666 environ = env = envp = argv + main_argc + 1;
667 dbg("move env from %p to %p", envp + rtld_argc, envp);
669 *envp = *(envp + rtld_argc);
670 } while (*envp++ != NULL);
671 aux = auxp = (Elf_Auxinfo *)envp;
672 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
673 dbg("move aux from %p to %p", auxpf, aux);
674 /* XXXKIB insert place for AT_EXECPATH if not present */
675 for (;; auxp++, auxpf++) {
677 if (auxp->a_type == AT_NULL)
680 /* Since the auxiliary vector has moved, redigest it. */
681 for (i = 0; i < AT_COUNT; i++)
683 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
684 if (auxp->a_type < AT_COUNT)
685 aux_info[auxp->a_type] = auxp;
688 /* Point AT_EXECPATH auxv and aux_info to the binary path. */
689 if (binpath == NULL) {
690 aux_info[AT_EXECPATH] = NULL;
692 if (aux_info[AT_EXECPATH] == NULL) {
693 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo));
694 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH;
696 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *,
700 _rtld_error("No binary");
706 ld_bind_now = ld_get_env_var(LD_BIND_NOW);
709 * If the process is tainted, then we un-set the dangerous environment
710 * variables. The process will be marked as tainted until setuid(2)
711 * is called. If any child process calls setuid(2) we do not want any
712 * future processes to honor the potentially un-safe variables.
715 for (i = 0; i < (int)nitems(ld_env_vars); i++) {
716 lvd = &ld_env_vars[i];
722 ld_debug = ld_get_env_var(LD_DEBUG);
723 if (ld_bind_now == NULL)
724 ld_bind_not = ld_get_env_var(LD_BIND_NOT) != NULL;
725 ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL;
726 libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL;
727 libmap_override = ld_get_env_var(LD_LIBMAP);
728 ld_library_path = ld_get_env_var(LD_LIBRARY_PATH);
729 ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS);
730 ld_preload = ld_get_env_var(LD_PRELOAD);
731 ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS);
732 ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH);
733 ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL;
734 library_path_rpath = ld_get_env_var(LD_LIBRARY_PATH_RPATH);
735 if (library_path_rpath != NULL) {
736 if (library_path_rpath[0] == 'y' ||
737 library_path_rpath[0] == 'Y' ||
738 library_path_rpath[0] == '1')
739 ld_library_path_rpath = true;
741 ld_library_path_rpath = false;
743 dangerous_ld_env = libmap_disable || libmap_override != NULL ||
744 ld_library_path != NULL || ld_preload != NULL ||
745 ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak;
746 ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS);
747 ld_utrace = ld_get_env_var(LD_UTRACE);
749 set_ld_elf_hints_path();
750 if (ld_debug != NULL && *ld_debug != '\0')
752 dbg("%s is initialized, base address = %p", __progname,
753 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
754 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
755 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
757 dbg("initializing thread locks");
761 * Load the main program, or process its program header if it is
764 if (fd != -1) { /* Load the main program. */
765 dbg("loading main program");
766 obj_main = map_object(fd, argv0, NULL);
768 if (obj_main == NULL)
770 max_stack_flags = obj_main->stack_flags;
771 } else { /* Main program already loaded. */
772 dbg("processing main program's program header");
773 assert(aux_info[AT_PHDR] != NULL);
774 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
775 assert(aux_info[AT_PHNUM] != NULL);
776 phnum = aux_info[AT_PHNUM]->a_un.a_val;
777 assert(aux_info[AT_PHENT] != NULL);
778 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
779 assert(aux_info[AT_ENTRY] != NULL);
780 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
781 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
785 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
786 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
787 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
788 if (kexecpath[0] == '/')
789 obj_main->path = kexecpath;
790 else if (getcwd(buf, sizeof(buf)) == NULL ||
791 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
792 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
793 obj_main->path = xstrdup(argv0);
795 obj_main->path = xstrdup(buf);
797 dbg("No AT_EXECPATH or direct exec");
798 obj_main->path = xstrdup(argv0);
800 dbg("obj_main path %s", obj_main->path);
801 obj_main->mainprog = true;
803 if (aux_info[AT_STACKPROT] != NULL &&
804 aux_info[AT_STACKPROT]->a_un.a_val != 0)
805 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
809 * Get the actual dynamic linker pathname from the executable if
810 * possible. (It should always be possible.) That ensures that
811 * gdb will find the right dynamic linker even if a non-standard
814 if (obj_main->interp != NULL &&
815 strcmp(obj_main->interp, obj_rtld.path) != 0) {
817 obj_rtld.path = xstrdup(obj_main->interp);
818 __progname = obj_rtld.path;
822 if (!digest_dynamic(obj_main, 0))
824 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
825 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
826 obj_main->dynsymcount);
828 linkmap_add(obj_main);
829 linkmap_add(&obj_rtld);
831 /* Link the main program into the list of objects. */
832 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
836 /* Initialize a fake symbol for resolving undefined weak references. */
837 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
838 sym_zero.st_shndx = SHN_UNDEF;
839 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
842 libmap_disable = (bool)lm_init(libmap_override);
844 if (aux_info[AT_KPRELOAD] != NULL &&
845 aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) {
846 dbg("loading kernel vdso");
847 if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1)
851 dbg("loading LD_PRELOAD_FDS libraries");
852 if (load_preload_objects(ld_preload_fds, true) == -1)
855 dbg("loading LD_PRELOAD libraries");
856 if (load_preload_objects(ld_preload, false) == -1)
858 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
860 dbg("loading needed objects");
861 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE :
865 /* Make a list of all objects loaded at startup. */
866 last_interposer = obj_main;
867 TAILQ_FOREACH(obj, &obj_list, next) {
870 if (obj->z_interpose && obj != obj_main) {
871 objlist_put_after(&list_main, last_interposer, obj);
872 last_interposer = obj;
874 objlist_push_tail(&list_main, obj);
879 dbg("checking for required versions");
880 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
883 if (ld_get_env_var(LD_SHOW_AUXV) != NULL)
886 if (ld_tracing) { /* We're done */
887 trace_loaded_objects(obj_main, true);
891 if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) {
892 dump_relocations(obj_main);
897 * Processing tls relocations requires having the tls offsets
898 * initialized. Prepare offsets before starting initial
899 * relocation processing.
901 dbg("initializing initial thread local storage offsets");
902 STAILQ_FOREACH(entry, &list_main, link) {
904 * Allocate all the initial objects out of the static TLS
905 * block even if they didn't ask for it.
907 allocate_tls_offset(entry->obj);
910 if (relocate_objects(obj_main,
911 ld_bind_now != NULL && *ld_bind_now != '\0',
912 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
915 dbg("doing copy relocations");
916 if (do_copy_relocations(obj_main) == -1)
919 if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) {
920 dump_relocations(obj_main);
927 * Setup TLS for main thread. This must be done after the
928 * relocations are processed, since tls initialization section
929 * might be the subject for relocations.
931 dbg("initializing initial thread local storage");
932 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
934 dbg("initializing key program variables");
935 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
936 set_program_var("environ", env);
937 set_program_var("__elf_aux_vector", aux);
939 /* Make a list of init functions to call. */
940 objlist_init(&initlist);
941 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
942 preload_tail, &initlist);
944 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
946 map_stacks_exec(NULL);
948 if (!obj_main->crt_no_init) {
950 * Make sure we don't call the main program's init and fini
951 * functions for binaries linked with old crt1 which calls
954 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
955 obj_main->preinit_array = obj_main->init_array =
956 obj_main->fini_array = (Elf_Addr)NULL;
960 /* Set osrel for direct-execed binary */
963 mib[2] = KERN_PROC_OSREL;
965 osrel = obj_main->osrel;
966 sz = sizeof(old_osrel);
967 dbg("setting osrel to %d", osrel);
968 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
971 wlock_acquire(rtld_bind_lock, &lockstate);
973 dbg("resolving ifuncs");
974 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
975 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
978 rtld_exit_ptr = rtld_exit;
979 if (obj_main->crt_no_init)
981 objlist_call_init(&initlist, &lockstate);
982 _r_debug_postinit(&obj_main->linkmap);
983 objlist_clear(&initlist);
984 dbg("loading filtees");
985 TAILQ_FOREACH(obj, &obj_list, next) {
988 if (ld_loadfltr || obj->z_loadfltr)
989 load_filtees(obj, 0, &lockstate);
992 dbg("enforcing main obj relro");
993 if (obj_enforce_relro(obj_main) == -1)
996 lock_release(rtld_bind_lock, &lockstate);
998 dbg("transferring control to program entry point = %p", obj_main->entry);
1000 /* Return the exit procedure and the program entry point. */
1001 *exit_proc = rtld_exit_ptr;
1003 return ((func_ptr_type)obj_main->entry);
1007 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
1012 ptr = (void *)make_function_pointer(def, obj);
1013 target = call_ifunc_resolver(ptr);
1014 return ((void *)target);
1018 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
1022 const Obj_Entry *defobj;
1025 RtldLockState lockstate;
1027 rlock_acquire(rtld_bind_lock, &lockstate);
1028 if (sigsetjmp(lockstate.env, 0) != 0)
1029 lock_upgrade(rtld_bind_lock, &lockstate);
1031 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
1033 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
1035 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
1036 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
1040 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
1041 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
1043 target = (Elf_Addr)(defobj->relocbase + def->st_value);
1045 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
1046 defobj->strtab + def->st_name,
1047 obj->path == NULL ? NULL : basename(obj->path),
1049 defobj->path == NULL ? NULL : basename(defobj->path));
1052 * Write the new contents for the jmpslot. Note that depending on
1053 * architecture, the value which we need to return back to the
1054 * lazy binding trampoline may or may not be the target
1055 * address. The value returned from reloc_jmpslot() is the value
1056 * that the trampoline needs.
1058 target = reloc_jmpslot(where, target, defobj, obj, rel);
1059 lock_release(rtld_bind_lock, &lockstate);
1064 * Error reporting function. Use it like printf. If formats the message
1065 * into a buffer, and sets things up so that the next call to dlerror()
1066 * will return the message.
1069 _rtld_error(const char *fmt, ...)
1074 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz,
1077 *lockinfo.dlerror_seen() = 0;
1078 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc());
1082 * Return a dynamically-allocated copy of the current error message, if any.
1084 static struct dlerror_save *
1087 struct dlerror_save *res;
1089 res = xmalloc(sizeof(*res));
1090 res->seen = *lockinfo.dlerror_seen();
1092 res->msg = xstrdup(lockinfo.dlerror_loc());
1097 * Restore the current error message from a copy which was previously saved
1098 * by errmsg_save(). The copy is freed.
1101 errmsg_restore(struct dlerror_save *saved_msg)
1103 if (saved_msg == NULL || saved_msg->seen == 1) {
1104 *lockinfo.dlerror_seen() = 1;
1106 *lockinfo.dlerror_seen() = 0;
1107 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg,
1108 lockinfo.dlerror_loc_sz);
1109 free(saved_msg->msg);
1115 basename(const char *name)
1119 p = strrchr(name, '/');
1120 return (p != NULL ? p + 1 : name);
1123 static struct utsname uts;
1126 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
1127 const char *subst, bool may_free)
1129 char *p, *p1, *res, *resp;
1130 int subst_len, kw_len, subst_count, old_len, new_len;
1132 kw_len = strlen(kw);
1135 * First, count the number of the keyword occurrences, to
1136 * preallocate the final string.
1138 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
1145 * If the keyword is not found, just return.
1147 * Return non-substituted string if resolution failed. We
1148 * cannot do anything more reasonable, the failure mode of the
1149 * caller is unresolved library anyway.
1151 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
1152 return (may_free ? real : xstrdup(real));
1154 subst = obj->origin_path;
1157 * There is indeed something to substitute. Calculate the
1158 * length of the resulting string, and allocate it.
1160 subst_len = strlen(subst);
1161 old_len = strlen(real);
1162 new_len = old_len + (subst_len - kw_len) * subst_count;
1163 res = xmalloc(new_len + 1);
1166 * Now, execute the substitution loop.
1168 for (p = real, resp = res, *resp = '\0';;) {
1171 /* Copy the prefix before keyword. */
1172 memcpy(resp, p, p1 - p);
1174 /* Keyword replacement. */
1175 memcpy(resp, subst, subst_len);
1183 /* Copy to the end of string and finish. */
1190 static const struct {
1195 { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL },
1196 { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL },
1197 { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname },
1198 { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname },
1199 { .kw = "$OSREL", .pass_obj = false, .subst = uts.release },
1200 { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release },
1201 { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine },
1202 { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine },
1203 { .kw = "$LIB", .pass_obj = false, .subst = TOKEN_LIB },
1204 { .kw = "${LIB}", .pass_obj = false, .subst = TOKEN_LIB },
1208 origin_subst(Obj_Entry *obj, const char *real)
1213 if (obj == NULL || !trust)
1214 return (xstrdup(real));
1215 if (uts.sysname[0] == '\0') {
1216 if (uname(&uts) != 0) {
1217 _rtld_error("utsname failed: %d", errno);
1222 /* __DECONST is safe here since without may_free real is unchanged */
1223 res = __DECONST(char *, real);
1224 for (i = 0; i < (int)nitems(tokens); i++) {
1225 res = origin_subst_one(tokens[i].pass_obj ? obj : NULL,
1226 res, tokens[i].kw, tokens[i].subst, i != 0);
1234 const char *msg = dlerror();
1237 msg = "Fatal error";
1238 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1239 rtld_fdputstr(STDERR_FILENO, msg);
1240 rtld_fdputchar(STDERR_FILENO, '\n');
1245 * Process a shared object's DYNAMIC section, and save the important
1246 * information in its Obj_Entry structure.
1249 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1250 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1252 const Elf_Dyn *dynp;
1253 Needed_Entry **needed_tail = &obj->needed;
1254 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1255 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1256 const Elf_Hashelt *hashtab;
1257 const Elf32_Word *hashval;
1258 Elf32_Word bkt, nmaskwords;
1260 int plttype = DT_REL;
1264 *dyn_runpath = NULL;
1266 obj->bind_now = false;
1267 dynp = obj->dynamic;
1270 for (; dynp->d_tag != DT_NULL; dynp++) {
1271 switch (dynp->d_tag) {
1274 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1278 obj->relsize = dynp->d_un.d_val;
1282 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1286 obj->pltrel = (const Elf_Rel *)
1287 (obj->relocbase + dynp->d_un.d_ptr);
1291 obj->pltrelsize = dynp->d_un.d_val;
1295 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1299 obj->relasize = dynp->d_un.d_val;
1303 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1307 obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr);
1311 obj->relrsize = dynp->d_un.d_val;
1315 assert(dynp->d_un.d_val == sizeof(Elf_Relr));
1319 plttype = dynp->d_un.d_val;
1320 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1324 obj->symtab = (const Elf_Sym *)
1325 (obj->relocbase + dynp->d_un.d_ptr);
1329 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1333 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1337 obj->strsize = dynp->d_un.d_val;
1341 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1346 obj->verneednum = dynp->d_un.d_val;
1350 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1355 obj->verdefnum = dynp->d_un.d_val;
1359 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1365 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1367 obj->nbuckets = hashtab[0];
1368 obj->nchains = hashtab[1];
1369 obj->buckets = hashtab + 2;
1370 obj->chains = obj->buckets + obj->nbuckets;
1371 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1372 obj->buckets != NULL;
1378 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1380 obj->nbuckets_gnu = hashtab[0];
1381 obj->symndx_gnu = hashtab[1];
1382 nmaskwords = hashtab[2];
1383 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1384 obj->maskwords_bm_gnu = nmaskwords - 1;
1385 obj->shift2_gnu = hashtab[3];
1386 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1387 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1388 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1390 /* Number of bitmask words is required to be power of 2 */
1391 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1392 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1398 Needed_Entry *nep = NEW(Needed_Entry);
1399 nep->name = dynp->d_un.d_val;
1404 needed_tail = &nep->next;
1410 Needed_Entry *nep = NEW(Needed_Entry);
1411 nep->name = dynp->d_un.d_val;
1415 *needed_filtees_tail = nep;
1416 needed_filtees_tail = &nep->next;
1418 if (obj->linkmap.l_refname == NULL)
1419 obj->linkmap.l_refname = (char *)dynp->d_un.d_val;
1425 Needed_Entry *nep = NEW(Needed_Entry);
1426 nep->name = dynp->d_un.d_val;
1430 *needed_aux_filtees_tail = nep;
1431 needed_aux_filtees_tail = &nep->next;
1436 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1440 obj->textrel = true;
1444 obj->symbolic = true;
1449 * We have to wait until later to process this, because we
1450 * might not have gotten the address of the string table yet.
1460 *dyn_runpath = dynp;
1464 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1467 case DT_PREINIT_ARRAY:
1468 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1471 case DT_PREINIT_ARRAYSZ:
1472 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1476 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1479 case DT_INIT_ARRAYSZ:
1480 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1484 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1488 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1491 case DT_FINI_ARRAYSZ:
1492 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1497 dbg("Filling in DT_DEBUG entry");
1498 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1502 if (dynp->d_un.d_val & DF_ORIGIN)
1503 obj->z_origin = true;
1504 if (dynp->d_un.d_val & DF_SYMBOLIC)
1505 obj->symbolic = true;
1506 if (dynp->d_un.d_val & DF_TEXTREL)
1507 obj->textrel = true;
1508 if (dynp->d_un.d_val & DF_BIND_NOW)
1509 obj->bind_now = true;
1510 if (dynp->d_un.d_val & DF_STATIC_TLS)
1511 obj->static_tls = true;
1515 #ifdef __powerpc64__
1516 case DT_PPC64_GLINK:
1517 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1521 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1527 if (dynp->d_un.d_val & DF_1_NOOPEN)
1528 obj->z_noopen = true;
1529 if (dynp->d_un.d_val & DF_1_ORIGIN)
1530 obj->z_origin = true;
1531 if (dynp->d_un.d_val & DF_1_GLOBAL)
1532 obj->z_global = true;
1533 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1534 obj->bind_now = true;
1535 if (dynp->d_un.d_val & DF_1_NODELETE)
1536 obj->z_nodelete = true;
1537 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1538 obj->z_loadfltr = true;
1539 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1540 obj->z_interpose = true;
1541 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1542 obj->z_nodeflib = true;
1543 if (dynp->d_un.d_val & DF_1_PIE)
1549 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1556 obj->traced = false;
1558 if (plttype == DT_RELA) {
1559 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1561 obj->pltrelasize = obj->pltrelsize;
1562 obj->pltrelsize = 0;
1565 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1566 if (obj->valid_hash_sysv)
1567 obj->dynsymcount = obj->nchains;
1568 else if (obj->valid_hash_gnu) {
1569 obj->dynsymcount = 0;
1570 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1571 if (obj->buckets_gnu[bkt] == 0)
1573 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1576 while ((*hashval++ & 1u) == 0);
1578 obj->dynsymcount += obj->symndx_gnu;
1581 if (obj->linkmap.l_refname != NULL)
1582 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj->
1587 obj_resolve_origin(Obj_Entry *obj)
1590 if (obj->origin_path != NULL)
1592 obj->origin_path = xmalloc(PATH_MAX);
1593 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1597 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1598 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1601 if (obj->z_origin && !obj_resolve_origin(obj))
1604 if (dyn_runpath != NULL) {
1605 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1606 obj->runpath = origin_subst(obj, obj->runpath);
1607 } else if (dyn_rpath != NULL) {
1608 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1609 obj->rpath = origin_subst(obj, obj->rpath);
1611 if (dyn_soname != NULL)
1612 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1617 digest_dynamic(Obj_Entry *obj, int early)
1619 const Elf_Dyn *dyn_rpath;
1620 const Elf_Dyn *dyn_soname;
1621 const Elf_Dyn *dyn_runpath;
1623 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1624 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1628 * Process a shared object's program header. This is used only for the
1629 * main program, when the kernel has already loaded the main program
1630 * into memory before calling the dynamic linker. It creates and
1631 * returns an Obj_Entry structure.
1634 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1637 const Elf_Phdr *phlimit = phdr + phnum;
1639 Elf_Addr note_start, note_end;
1643 for (ph = phdr; ph < phlimit; ph++) {
1644 if (ph->p_type != PT_PHDR)
1648 obj->phsize = ph->p_memsz;
1649 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1653 obj->stack_flags = PF_X | PF_R | PF_W;
1655 for (ph = phdr; ph < phlimit; ph++) {
1656 switch (ph->p_type) {
1659 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1663 if (nsegs == 0) { /* First load segment */
1664 obj->vaddrbase = rtld_trunc_page(ph->p_vaddr);
1665 obj->mapbase = obj->vaddrbase + obj->relocbase;
1666 } else { /* Last load segment */
1667 obj->mapsize = rtld_round_page(ph->p_vaddr + ph->p_memsz) -
1674 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1679 obj->tlssize = ph->p_memsz;
1680 obj->tlsalign = ph->p_align;
1681 obj->tlsinitsize = ph->p_filesz;
1682 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1683 obj->tlspoffset = ph->p_offset;
1687 obj->stack_flags = ph->p_flags;
1691 obj->relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
1692 obj->relro_size = rtld_trunc_page(ph->p_vaddr + ph->p_memsz) -
1693 rtld_trunc_page(ph->p_vaddr);
1697 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1698 note_end = note_start + ph->p_filesz;
1699 digest_notes(obj, note_start, note_end);
1704 _rtld_error("%s: too few PT_LOAD segments", path);
1713 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1715 const Elf_Note *note;
1716 const char *note_name;
1719 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1720 note = (const Elf_Note *)((const char *)(note + 1) +
1721 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1722 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1723 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1724 note->n_descsz != sizeof(int32_t))
1726 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1727 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1728 note->n_type != NT_FREEBSD_NOINIT_TAG)
1730 note_name = (const char *)(note + 1);
1731 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1732 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1734 switch (note->n_type) {
1735 case NT_FREEBSD_ABI_TAG:
1736 /* FreeBSD osrel note */
1737 p = (uintptr_t)(note + 1);
1738 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1739 obj->osrel = *(const int32_t *)(p);
1740 dbg("note osrel %d", obj->osrel);
1742 case NT_FREEBSD_FEATURE_CTL:
1743 /* FreeBSD ABI feature control note */
1744 p = (uintptr_t)(note + 1);
1745 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1746 obj->fctl0 = *(const uint32_t *)(p);
1747 dbg("note fctl0 %#x", obj->fctl0);
1749 case NT_FREEBSD_NOINIT_TAG:
1750 /* FreeBSD 'crt does not call init' note */
1751 obj->crt_no_init = true;
1752 dbg("note crt_no_init");
1759 dlcheck(void *handle)
1763 TAILQ_FOREACH(obj, &obj_list, next) {
1764 if (obj == (Obj_Entry *) handle)
1768 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1769 _rtld_error("Invalid shared object handle %p", handle);
1776 * If the given object is already in the donelist, return true. Otherwise
1777 * add the object to the list and return false.
1780 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1784 for (i = 0; i < dlp->num_used; i++)
1785 if (dlp->objs[i] == obj)
1788 * Our donelist allocation should always be sufficient. But if
1789 * our threads locking isn't working properly, more shared objects
1790 * could have been loaded since we allocated the list. That should
1791 * never happen, but we'll handle it properly just in case it does.
1793 if (dlp->num_used < dlp->num_alloc)
1794 dlp->objs[dlp->num_used++] = obj;
1799 * SysV hash function for symbol table lookup. It is a slightly optimized
1800 * version of the hash specified by the System V ABI.
1803 elf_hash(const char *name)
1805 const unsigned char *p = (const unsigned char *)name;
1808 while (*p != '\0') {
1809 h = (h << 4) + *p++;
1810 h ^= (h >> 24) & 0xf0;
1812 return (h & 0x0fffffff);
1816 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1817 * unsigned in case it's implemented with a wider type.
1820 gnu_hash(const char *s)
1826 for (c = *s; c != '\0'; c = *++s)
1828 return (h & 0xffffffff);
1833 * Find the library with the given name, and return its full pathname.
1834 * The returned string is dynamically allocated. Generates an error
1835 * message and returns NULL if the library cannot be found.
1837 * If the second argument is non-NULL, then it refers to an already-
1838 * loaded shared object, whose library search path will be searched.
1840 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1841 * descriptor (which is close-on-exec) will be passed out via the third
1844 * The search order is:
1845 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1846 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1848 * DT_RUNPATH in the referencing file
1849 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1851 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1853 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1856 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1858 char *pathname, *refobj_path;
1860 bool nodeflib, objgiven;
1862 objgiven = refobj != NULL;
1864 if (libmap_disable || !objgiven ||
1865 (name = lm_find(refobj->path, xname)) == NULL)
1868 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1869 if (name[0] != '/' && !trust) {
1870 _rtld_error("Absolute pathname required "
1871 "for shared object \"%s\"", name);
1874 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1875 __DECONST(char *, name)));
1878 dbg(" Searching for \"%s\"", name);
1879 refobj_path = objgiven ? refobj->path : NULL;
1882 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1883 * back to pre-conforming behaviour if user requested so with
1884 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1887 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1888 pathname = search_library_path(name, ld_library_path,
1890 if (pathname != NULL)
1892 if (refobj != NULL) {
1893 pathname = search_library_path(name, refobj->rpath,
1895 if (pathname != NULL)
1898 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1899 if (pathname != NULL)
1901 pathname = search_library_path(name, gethints(false),
1903 if (pathname != NULL)
1905 pathname = search_library_path(name, ld_standard_library_path,
1907 if (pathname != NULL)
1910 nodeflib = objgiven ? refobj->z_nodeflib : false;
1912 pathname = search_library_path(name, refobj->rpath,
1914 if (pathname != NULL)
1917 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1918 pathname = search_library_path(name, obj_main->rpath,
1920 if (pathname != NULL)
1923 pathname = search_library_path(name, ld_library_path,
1925 if (pathname != NULL)
1928 pathname = search_library_path(name, refobj->runpath,
1930 if (pathname != NULL)
1933 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1934 if (pathname != NULL)
1936 pathname = search_library_path(name, gethints(nodeflib),
1938 if (pathname != NULL)
1940 if (objgiven && !nodeflib) {
1941 pathname = search_library_path(name,
1942 ld_standard_library_path, refobj_path, fdp);
1943 if (pathname != NULL)
1948 if (objgiven && refobj->path != NULL) {
1949 _rtld_error("Shared object \"%s\" not found, "
1950 "required by \"%s\"", name, basename(refobj->path));
1952 _rtld_error("Shared object \"%s\" not found", name);
1958 * Given a symbol number in a referencing object, find the corresponding
1959 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1960 * no definition was found. Returns a pointer to the Obj_Entry of the
1961 * defining object via the reference parameter DEFOBJ_OUT.
1964 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1965 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1966 RtldLockState *lockstate)
1970 const Obj_Entry *defobj;
1971 const Ver_Entry *ve;
1977 * If we have already found this symbol, get the information from
1980 if (symnum >= refobj->dynsymcount)
1981 return (NULL); /* Bad object */
1982 if (cache != NULL && cache[symnum].sym != NULL) {
1983 *defobj_out = cache[symnum].obj;
1984 return (cache[symnum].sym);
1987 ref = refobj->symtab + symnum;
1988 name = refobj->strtab + ref->st_name;
1994 * We don't have to do a full scale lookup if the symbol is local.
1995 * We know it will bind to the instance in this load module; to
1996 * which we already have a pointer (ie ref). By not doing a lookup,
1997 * we not only improve performance, but it also avoids unresolvable
1998 * symbols when local symbols are not in the hash table. This has
1999 * been seen with the ia64 toolchain.
2001 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
2002 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
2003 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
2006 symlook_init(&req, name);
2008 ve = req.ventry = fetch_ventry(refobj, symnum);
2009 req.lockstate = lockstate;
2010 res = symlook_default(&req, refobj);
2013 defobj = req.defobj_out;
2021 * If we found no definition and the reference is weak, treat the
2022 * symbol as having the value zero.
2024 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
2030 *defobj_out = defobj;
2031 /* Record the information in the cache to avoid subsequent lookups. */
2032 if (cache != NULL) {
2033 cache[symnum].sym = def;
2034 cache[symnum].obj = defobj;
2037 if (refobj != &obj_rtld)
2038 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
2039 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
2045 * Return the search path from the ldconfig hints file, reading it if
2046 * necessary. If nostdlib is true, then the default search paths are
2047 * not added to result.
2049 * Returns NULL if there are problems with the hints file,
2050 * or if the search path there is empty.
2053 gethints(bool nostdlib)
2055 static char *filtered_path;
2056 static const char *hints;
2057 static struct elfhints_hdr hdr;
2058 struct fill_search_info_args sargs, hargs;
2059 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
2060 struct dl_serpath *SLPpath, *hintpath;
2062 struct stat hint_stat;
2063 unsigned int SLPndx, hintndx, fndx, fcount;
2069 /* First call, read the hints file */
2070 if (hints == NULL) {
2071 /* Keep from trying again in case the hints file is bad. */
2074 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
2078 * Check of hdr.dirlistlen value against type limit
2079 * intends to pacify static analyzers. Further
2080 * paranoia leads to checks that dirlist is fully
2081 * contained in the file range.
2083 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
2084 hdr.magic != ELFHINTS_MAGIC ||
2085 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
2086 fstat(fd, &hint_stat) == -1) {
2093 if (dl + hdr.dirlist < dl)
2096 if (dl + hdr.dirlistlen < dl)
2098 dl += hdr.dirlistlen;
2099 if (dl > hint_stat.st_size)
2101 p = xmalloc(hdr.dirlistlen + 1);
2102 if (pread(fd, p, hdr.dirlistlen + 1,
2103 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
2104 p[hdr.dirlistlen] != '\0') {
2113 * If caller agreed to receive list which includes the default
2114 * paths, we are done. Otherwise, if we still did not
2115 * calculated filtered result, do it now.
2118 return (hints[0] != '\0' ? hints : NULL);
2119 if (filtered_path != NULL)
2123 * Obtain the list of all configured search paths, and the
2124 * list of the default paths.
2126 * First estimate the size of the results.
2128 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2130 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2133 sargs.request = RTLD_DI_SERINFOSIZE;
2134 sargs.serinfo = &smeta;
2135 hargs.request = RTLD_DI_SERINFOSIZE;
2136 hargs.serinfo = &hmeta;
2138 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2140 path_enumerate(hints, fill_search_info, NULL, &hargs);
2142 SLPinfo = xmalloc(smeta.dls_size);
2143 hintinfo = xmalloc(hmeta.dls_size);
2146 * Next fetch both sets of paths.
2148 sargs.request = RTLD_DI_SERINFO;
2149 sargs.serinfo = SLPinfo;
2150 sargs.serpath = &SLPinfo->dls_serpath[0];
2151 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
2153 hargs.request = RTLD_DI_SERINFO;
2154 hargs.serinfo = hintinfo;
2155 hargs.serpath = &hintinfo->dls_serpath[0];
2156 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
2158 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2160 path_enumerate(hints, fill_search_info, NULL, &hargs);
2163 * Now calculate the difference between two sets, by excluding
2164 * standard paths from the full set.
2168 filtered_path = xmalloc(hdr.dirlistlen + 1);
2169 hintpath = &hintinfo->dls_serpath[0];
2170 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
2172 SLPpath = &SLPinfo->dls_serpath[0];
2174 * Check each standard path against current.
2176 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
2177 /* matched, skip the path */
2178 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2186 * Not matched against any standard path, add the path
2187 * to result. Separate consequtive paths with ':'.
2190 filtered_path[fndx] = ':';
2194 flen = strlen(hintpath->dls_name);
2195 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2198 filtered_path[fndx] = '\0';
2204 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2208 init_dag(Obj_Entry *root)
2210 const Needed_Entry *needed;
2211 const Objlist_Entry *elm;
2214 if (root->dag_inited)
2216 donelist_init(&donelist);
2218 /* Root object belongs to own DAG. */
2219 objlist_push_tail(&root->dldags, root);
2220 objlist_push_tail(&root->dagmembers, root);
2221 donelist_check(&donelist, root);
2224 * Add dependencies of root object to DAG in breadth order
2225 * by exploiting the fact that each new object get added
2226 * to the tail of the dagmembers list.
2228 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2229 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
2230 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
2232 objlist_push_tail(&needed->obj->dldags, root);
2233 objlist_push_tail(&root->dagmembers, needed->obj);
2236 root->dag_inited = true;
2240 init_marker(Obj_Entry *marker)
2243 bzero(marker, sizeof(*marker));
2244 marker->marker = true;
2248 globallist_curr(const Obj_Entry *obj)
2255 return (__DECONST(Obj_Entry *, obj));
2256 obj = TAILQ_PREV(obj, obj_entry_q, next);
2261 globallist_next(const Obj_Entry *obj)
2265 obj = TAILQ_NEXT(obj, next);
2269 return (__DECONST(Obj_Entry *, obj));
2273 /* Prevent the object from being unmapped while the bind lock is dropped. */
2275 hold_object(Obj_Entry *obj)
2282 unhold_object(Obj_Entry *obj)
2285 assert(obj->holdcount > 0);
2286 if (--obj->holdcount == 0 && obj->unholdfree)
2287 release_object(obj);
2291 process_z(Obj_Entry *root)
2293 const Objlist_Entry *elm;
2297 * Walk over object DAG and process every dependent object
2298 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2299 * to grow their own DAG.
2301 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2302 * symlook_global() to work.
2304 * For DF_1_NODELETE, the DAG should have its reference upped.
2306 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2310 if (obj->z_nodelete && !obj->ref_nodel) {
2311 dbg("obj %s -z nodelete", obj->path);
2314 obj->ref_nodel = true;
2316 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2317 dbg("obj %s -z global", obj->path);
2318 objlist_push_tail(&list_global, obj);
2325 parse_rtld_phdr(Obj_Entry *obj)
2328 Elf_Addr note_start, note_end;
2330 obj->stack_flags = PF_X | PF_R | PF_W;
2331 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr +
2332 obj->phsize; ph++) {
2333 switch (ph->p_type) {
2335 obj->stack_flags = ph->p_flags;
2338 obj->relro_page = obj->relocbase +
2339 rtld_trunc_page(ph->p_vaddr);
2340 obj->relro_size = rtld_round_page(ph->p_memsz);
2343 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
2344 note_end = note_start + ph->p_filesz;
2345 digest_notes(obj, note_start, note_end);
2352 * Initialize the dynamic linker. The argument is the address at which
2353 * the dynamic linker has been mapped into memory. The primary task of
2354 * this function is to relocate the dynamic linker.
2357 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2359 Obj_Entry objtmp; /* Temporary rtld object */
2360 const Elf_Ehdr *ehdr;
2361 const Elf_Dyn *dyn_rpath;
2362 const Elf_Dyn *dyn_soname;
2363 const Elf_Dyn *dyn_runpath;
2365 #ifdef RTLD_INIT_PAGESIZES_EARLY
2366 /* The page size is required by the dynamic memory allocator. */
2367 init_pagesizes(aux_info);
2371 * Conjure up an Obj_Entry structure for the dynamic linker.
2373 * The "path" member can't be initialized yet because string constants
2374 * cannot yet be accessed. Below we will set it correctly.
2376 memset(&objtmp, 0, sizeof(objtmp));
2379 objtmp.mapbase = mapbase;
2381 objtmp.relocbase = mapbase;
2384 objtmp.dynamic = rtld_dynamic(&objtmp);
2385 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2386 assert(objtmp.needed == NULL);
2387 assert(!objtmp.textrel);
2389 * Temporarily put the dynamic linker entry into the object list, so
2390 * that symbols can be found.
2392 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2394 ehdr = (Elf_Ehdr *)mapbase;
2395 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2396 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2398 /* Initialize the object list. */
2399 TAILQ_INIT(&obj_list);
2401 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2402 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2404 #ifndef RTLD_INIT_PAGESIZES_EARLY
2405 /* The page size is required by the dynamic memory allocator. */
2406 init_pagesizes(aux_info);
2409 if (aux_info[AT_OSRELDATE] != NULL)
2410 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2412 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2414 /* Replace the path with a dynamically allocated copy. */
2415 obj_rtld.path = xstrdup(ld_path_rtld);
2417 parse_rtld_phdr(&obj_rtld);
2418 if (obj_enforce_relro(&obj_rtld) == -1)
2421 r_debug.r_version = R_DEBUG_VERSION;
2422 r_debug.r_brk = r_debug_state;
2423 r_debug.r_state = RT_CONSISTENT;
2424 r_debug.r_ldbase = obj_rtld.relocbase;
2428 * Retrieve the array of supported page sizes. The kernel provides the page
2429 * sizes in increasing order.
2432 init_pagesizes(Elf_Auxinfo **aux_info)
2434 static size_t psa[MAXPAGESIZES];
2438 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2440 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2441 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2444 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2447 /* As a fallback, retrieve the base page size. */
2448 size = sizeof(psa[0]);
2449 if (aux_info[AT_PAGESZ] != NULL) {
2450 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2454 mib[1] = HW_PAGESIZE;
2458 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2459 _rtld_error("sysctl for hw.pagesize(s) failed");
2465 npagesizes = size / sizeof(pagesizes[0]);
2466 /* Discard any invalid entries at the end of the array. */
2467 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2470 page_size = pagesizes[0];
2474 * Add the init functions from a needed object list (and its recursive
2475 * needed objects) to "list". This is not used directly; it is a helper
2476 * function for initlist_add_objects(). The write lock must be held
2477 * when this function is called.
2480 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2482 /* Recursively process the successor needed objects. */
2483 if (needed->next != NULL)
2484 initlist_add_neededs(needed->next, list);
2486 /* Process the current needed object. */
2487 if (needed->obj != NULL)
2488 initlist_add_objects(needed->obj, needed->obj, list);
2492 * Scan all of the DAGs rooted in the range of objects from "obj" to
2493 * "tail" and add their init functions to "list". This recurses over
2494 * the DAGs and ensure the proper init ordering such that each object's
2495 * needed libraries are initialized before the object itself. At the
2496 * same time, this function adds the objects to the global finalization
2497 * list "list_fini" in the opposite order. The write lock must be
2498 * held when this function is called.
2501 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2505 if (obj->init_scanned || obj->init_done)
2507 obj->init_scanned = true;
2509 /* Recursively process the successor objects. */
2510 nobj = globallist_next(obj);
2511 if (nobj != NULL && obj != tail)
2512 initlist_add_objects(nobj, tail, list);
2514 /* Recursively process the needed objects. */
2515 if (obj->needed != NULL)
2516 initlist_add_neededs(obj->needed, list);
2517 if (obj->needed_filtees != NULL)
2518 initlist_add_neededs(obj->needed_filtees, list);
2519 if (obj->needed_aux_filtees != NULL)
2520 initlist_add_neededs(obj->needed_aux_filtees, list);
2522 /* Add the object to the init list. */
2523 objlist_push_tail(list, obj);
2525 /* Add the object to the global fini list in the reverse order. */
2526 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2527 && !obj->on_fini_list) {
2528 objlist_push_head(&list_fini, obj);
2529 obj->on_fini_list = true;
2534 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2536 Needed_Entry *needed, *needed1;
2538 for (needed = n; needed != NULL; needed = needed->next) {
2539 if (needed->obj != NULL) {
2540 dlclose_locked(needed->obj, lockstate);
2544 for (needed = n; needed != NULL; needed = needed1) {
2545 needed1 = needed->next;
2551 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2554 free_needed_filtees(obj->needed_filtees, lockstate);
2555 obj->needed_filtees = NULL;
2556 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2557 obj->needed_aux_filtees = NULL;
2558 obj->filtees_loaded = false;
2562 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2563 RtldLockState *lockstate)
2566 for (; needed != NULL; needed = needed->next) {
2567 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2568 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2569 RTLD_LOCAL, lockstate);
2574 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2577 lock_restart_for_upgrade(lockstate);
2578 if (!obj->filtees_loaded) {
2579 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2580 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2581 obj->filtees_loaded = true;
2586 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2590 for (; needed != NULL; needed = needed->next) {
2591 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2592 flags & ~RTLD_LO_NOLOAD);
2593 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2600 * Given a shared object, traverse its list of needed objects, and load
2601 * each of them. Returns 0 on success. Generates an error message and
2602 * returns -1 on failure.
2605 load_needed_objects(Obj_Entry *first, int flags)
2609 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2612 if (process_needed(obj, obj->needed, flags) == -1)
2619 load_preload_objects(const char *penv, bool isfd)
2624 char savech, *p, *psave;
2626 static const char delim[] = " \t:;";
2631 p = psave = xstrdup(penv);
2632 p += strspn(p, delim);
2633 while (*p != '\0') {
2634 len = strcspn(p, delim);
2640 fd = parse_integer(p);
2650 obj = load_object(name, fd, NULL, 0);
2653 return (-1); /* XXX - cleanup */
2655 obj->z_interpose = true;
2658 p += strspn(p, delim);
2660 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2667 printable_path(const char *path)
2670 return (path == NULL ? "<unknown>" : path);
2674 * Load a shared object into memory, if it is not already loaded. The
2675 * object may be specified by name or by user-supplied file descriptor
2676 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2679 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2683 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2692 TAILQ_FOREACH(obj, &obj_list, next) {
2693 if (obj->marker || obj->doomed)
2695 if (object_match_name(obj, name))
2699 path = find_library(name, refobj, &fd);
2707 * search_library_pathfds() opens a fresh file descriptor for the
2708 * library, so there is no need to dup().
2710 } else if (fd_u == -1) {
2712 * If we didn't find a match by pathname, or the name is not
2713 * supplied, open the file and check again by device and inode.
2714 * This avoids false mismatches caused by multiple links or ".."
2717 * To avoid a race, we open the file and use fstat() rather than
2720 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2721 _rtld_error("Cannot open \"%s\"", path);
2726 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2728 _rtld_error("Cannot dup fd");
2733 if (fstat(fd, &sb) == -1) {
2734 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2739 TAILQ_FOREACH(obj, &obj_list, next) {
2740 if (obj->marker || obj->doomed)
2742 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2745 if (obj != NULL && name != NULL) {
2746 object_add_name(obj, name);
2751 if (flags & RTLD_LO_NOLOAD) {
2757 /* First use of this object, so we must map it in */
2758 obj = do_load_object(fd, name, path, &sb, flags);
2767 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2774 * First, make sure that environment variables haven't been
2775 * used to circumvent the noexec flag on a filesystem.
2776 * We ignore fstatfs(2) failures, since fd might reference
2777 * not a file, e.g. shmfd.
2779 if (dangerous_ld_env && fstatfs(fd, &fs) == 0 &&
2780 (fs.f_flags & MNT_NOEXEC) != 0) {
2781 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2785 dbg("loading \"%s\"", printable_path(path));
2786 obj = map_object(fd, printable_path(path), sbp);
2791 * If DT_SONAME is present in the object, digest_dynamic2 already
2792 * added it to the object names.
2795 object_add_name(obj, name);
2797 if (!digest_dynamic(obj, 0))
2799 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2800 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2801 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) {
2802 dbg("refusing to load PIE executable \"%s\"", obj->path);
2803 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
2806 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2808 dbg("refusing to load non-loadable \"%s\"", obj->path);
2809 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2813 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2814 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2817 linkmap_add(obj); /* for GDB & dlinfo() */
2818 max_stack_flags |= obj->stack_flags;
2820 dbg(" %p .. %p: %s", obj->mapbase,
2821 obj->mapbase + obj->mapsize - 1, obj->path);
2823 dbg(" WARNING: %s has impure text", obj->path);
2824 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2830 munmap(obj->mapbase, obj->mapsize);
2836 load_kpreload(const void *addr)
2839 const Elf_Ehdr *ehdr;
2840 const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn;
2841 static const char kname[] = "[vdso]";
2844 if (!check_elf_headers(ehdr, "kpreload"))
2847 phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff);
2849 obj->phsize = ehdr->e_phnum * sizeof(*phdr);
2850 phlimit = phdr + ehdr->e_phnum;
2853 for (; phdr < phlimit; phdr++) {
2854 switch (phdr->p_type) {
2859 /* Absense of PT_GNU_STACK implies stack_flags == 0. */
2860 obj->stack_flags = phdr->p_flags;
2863 if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr)
2865 if (segn == NULL || segn->p_vaddr + segn->p_memsz <
2866 phdr->p_vaddr + phdr->p_memsz)
2872 obj->mapbase = __DECONST(caddr_t, addr);
2873 obj->mapsize = segn->p_vaddr + segn->p_memsz - (Elf_Addr)addr;
2875 obj->relocbase = obj->mapbase;
2877 object_add_name(obj, kname);
2878 obj->path = xstrdup(kname);
2879 obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr);
2881 if (!digest_dynamic(obj, 0)) {
2887 * We assume that kernel-preloaded object does not need
2888 * relocation. It is currently written into read-only page,
2889 * handling relocations would mean we need to allocate at
2890 * least one additional page per AS.
2892 dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p",
2893 obj->path, obj->mapbase, obj->phdr, seg0,
2894 obj->relocbase + seg0->p_vaddr, obj->dynamic);
2896 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2899 linkmap_add(obj); /* for GDB & dlinfo() */
2900 max_stack_flags |= obj->stack_flags;
2902 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, 0, 0, obj->path);
2907 obj_from_addr(const void *addr)
2911 TAILQ_FOREACH(obj, &obj_list, next) {
2914 if (addr < (void *) obj->mapbase)
2916 if (addr < (void *)(obj->mapbase + obj->mapsize))
2925 Elf_Addr *preinit_addr;
2928 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2929 if (preinit_addr == NULL)
2932 for (index = 0; index < obj_main->preinit_array_num; index++) {
2933 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2934 dbg("calling preinit function for %s at %p", obj_main->path,
2935 (void *)preinit_addr[index]);
2936 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2937 0, 0, obj_main->path);
2938 call_init_pointer(obj_main, preinit_addr[index]);
2944 * Call the finalization functions for each of the objects in "list"
2945 * belonging to the DAG of "root" and referenced once. If NULL "root"
2946 * is specified, every finalization function will be called regardless
2947 * of the reference count and the list elements won't be freed. All of
2948 * the objects are expected to have non-NULL fini functions.
2951 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2954 struct dlerror_save *saved_msg;
2955 Elf_Addr *fini_addr;
2958 assert(root == NULL || root->refcount == 1);
2961 root->doomed = true;
2964 * Preserve the current error message since a fini function might
2965 * call into the dynamic linker and overwrite it.
2967 saved_msg = errmsg_save();
2969 STAILQ_FOREACH(elm, list, link) {
2970 if (root != NULL && (elm->obj->refcount != 1 ||
2971 objlist_find(&root->dagmembers, elm->obj) == NULL))
2973 /* Remove object from fini list to prevent recursive invocation. */
2974 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2975 /* Ensure that new references cannot be acquired. */
2976 elm->obj->doomed = true;
2978 hold_object(elm->obj);
2979 lock_release(rtld_bind_lock, lockstate);
2981 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2982 * When this happens, DT_FINI_ARRAY is processed first.
2984 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2985 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2986 for (index = elm->obj->fini_array_num - 1; index >= 0;
2988 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2989 dbg("calling fini function for %s at %p",
2990 elm->obj->path, (void *)fini_addr[index]);
2991 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2992 (void *)fini_addr[index], 0, 0, elm->obj->path);
2993 call_initfini_pointer(elm->obj, fini_addr[index]);
2997 if (elm->obj->fini != (Elf_Addr)NULL) {
2998 dbg("calling fini function for %s at %p", elm->obj->path,
2999 (void *)elm->obj->fini);
3000 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
3001 0, 0, elm->obj->path);
3002 call_initfini_pointer(elm->obj, elm->obj->fini);
3004 wlock_acquire(rtld_bind_lock, lockstate);
3005 unhold_object(elm->obj);
3006 /* No need to free anything if process is going down. */
3010 * We must restart the list traversal after every fini call
3011 * because a dlclose() call from the fini function or from
3012 * another thread might have modified the reference counts.
3016 } while (elm != NULL);
3017 errmsg_restore(saved_msg);
3021 * Call the initialization functions for each of the objects in
3022 * "list". All of the objects are expected to have non-NULL init
3026 objlist_call_init(Objlist *list, RtldLockState *lockstate)
3030 struct dlerror_save *saved_msg;
3031 Elf_Addr *init_addr;
3032 void (*reg)(void (*)(void));
3036 * Clean init_scanned flag so that objects can be rechecked and
3037 * possibly initialized earlier if any of vectors called below
3038 * cause the change by using dlopen.
3040 TAILQ_FOREACH(obj, &obj_list, next) {
3043 obj->init_scanned = false;
3047 * Preserve the current error message since an init function might
3048 * call into the dynamic linker and overwrite it.
3050 saved_msg = errmsg_save();
3051 STAILQ_FOREACH(elm, list, link) {
3052 if (elm->obj->init_done) /* Initialized early. */
3055 * Race: other thread might try to use this object before current
3056 * one completes the initialization. Not much can be done here
3057 * without better locking.
3059 elm->obj->init_done = true;
3060 hold_object(elm->obj);
3062 if (elm->obj == obj_main && obj_main->crt_no_init) {
3063 reg = (void (*)(void (*)(void)))get_program_var_addr(
3064 "__libc_atexit", lockstate);
3066 lock_release(rtld_bind_lock, lockstate);
3069 rtld_exit_ptr = rtld_nop_exit;
3073 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
3074 * When this happens, DT_INIT is processed first.
3076 if (elm->obj->init != (Elf_Addr)NULL) {
3077 dbg("calling init function for %s at %p", elm->obj->path,
3078 (void *)elm->obj->init);
3079 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
3080 0, 0, elm->obj->path);
3081 call_init_pointer(elm->obj, elm->obj->init);
3083 init_addr = (Elf_Addr *)elm->obj->init_array;
3084 if (init_addr != NULL) {
3085 for (index = 0; index < elm->obj->init_array_num; index++) {
3086 if (init_addr[index] != 0 && init_addr[index] != 1) {
3087 dbg("calling init function for %s at %p", elm->obj->path,
3088 (void *)init_addr[index]);
3089 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
3090 (void *)init_addr[index], 0, 0, elm->obj->path);
3091 call_init_pointer(elm->obj, init_addr[index]);
3095 wlock_acquire(rtld_bind_lock, lockstate);
3096 unhold_object(elm->obj);
3098 errmsg_restore(saved_msg);
3102 objlist_clear(Objlist *list)
3106 while (!STAILQ_EMPTY(list)) {
3107 elm = STAILQ_FIRST(list);
3108 STAILQ_REMOVE_HEAD(list, link);
3113 static Objlist_Entry *
3114 objlist_find(Objlist *list, const Obj_Entry *obj)
3118 STAILQ_FOREACH(elm, list, link)
3119 if (elm->obj == obj)
3125 objlist_init(Objlist *list)
3131 objlist_push_head(Objlist *list, Obj_Entry *obj)
3135 elm = NEW(Objlist_Entry);
3137 STAILQ_INSERT_HEAD(list, elm, link);
3141 objlist_push_tail(Objlist *list, Obj_Entry *obj)
3145 elm = NEW(Objlist_Entry);
3147 STAILQ_INSERT_TAIL(list, elm, link);
3151 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
3153 Objlist_Entry *elm, *listelm;
3155 STAILQ_FOREACH(listelm, list, link) {
3156 if (listelm->obj == listobj)
3159 elm = NEW(Objlist_Entry);
3161 if (listelm != NULL)
3162 STAILQ_INSERT_AFTER(list, listelm, elm, link);
3164 STAILQ_INSERT_TAIL(list, elm, link);
3168 objlist_remove(Objlist *list, Obj_Entry *obj)
3172 if ((elm = objlist_find(list, obj)) != NULL) {
3173 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
3179 * Relocate dag rooted in the specified object.
3180 * Returns 0 on success, or -1 on failure.
3184 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
3185 int flags, RtldLockState *lockstate)
3191 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3192 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
3201 * Prepare for, or clean after, relocating an object marked with
3202 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
3203 * segments are remapped read-write. After relocations are done, the
3204 * segment's permissions are returned back to the modes specified in
3205 * the phdrs. If any relocation happened, or always for wired
3206 * program, COW is triggered.
3209 reloc_textrel_prot(Obj_Entry *obj, bool before)
3216 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
3218 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
3220 base = obj->relocbase + rtld_trunc_page(ph->p_vaddr);
3221 sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) -
3222 rtld_trunc_page(ph->p_vaddr);
3223 prot = before ? (PROT_READ | PROT_WRITE) :
3224 convert_prot(ph->p_flags);
3225 if (mprotect(base, sz, prot) == -1) {
3226 _rtld_error("%s: Cannot write-%sable text segment: %s",
3227 obj->path, before ? "en" : "dis",
3228 rtld_strerror(errno));
3235 /* Process RELR relative relocations. */
3237 reloc_relr(Obj_Entry *obj)
3239 const Elf_Relr *relr, *relrlim;
3242 relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize);
3243 for (relr = obj->relr; relr < relrlim; relr++) {
3244 Elf_Relr entry = *relr;
3246 if ((entry & 1) == 0) {
3247 where = (Elf_Addr *)(obj->relocbase + entry);
3248 *where++ += (Elf_Addr)obj->relocbase;
3250 for (long i = 0; (entry >>= 1) != 0; i++)
3251 if ((entry & 1) != 0)
3252 where[i] += (Elf_Addr)obj->relocbase;
3253 where += CHAR_BIT * sizeof(Elf_Relr) - 1;
3259 * Relocate single object.
3260 * Returns 0 on success, or -1 on failure.
3263 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
3264 int flags, RtldLockState *lockstate)
3269 obj->relocated = true;
3271 dbg("relocating \"%s\"", obj->path);
3273 if (obj->symtab == NULL || obj->strtab == NULL ||
3274 !(obj->valid_hash_sysv || obj->valid_hash_gnu))
3275 dbg("object %s has no run-time symbol table", obj->path);
3277 /* There are relocations to the write-protected text segment. */
3278 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
3281 /* Process the non-PLT non-IFUNC relocations. */
3282 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
3286 /* Re-protected the text segment. */
3287 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
3290 /* Set the special PLT or GOT entries. */
3293 /* Process the PLT relocations. */
3294 if (reloc_plt(obj, flags, lockstate) == -1)
3296 /* Relocate the jump slots if we are doing immediate binding. */
3297 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
3301 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
3305 * Set up the magic number and version in the Obj_Entry. These
3306 * were checked in the crt1.o from the original ElfKit, so we
3307 * set them for backward compatibility.
3309 obj->magic = RTLD_MAGIC;
3310 obj->version = RTLD_VERSION;
3316 * Relocate newly-loaded shared objects. The argument is a pointer to
3317 * the Obj_Entry for the first such object. All objects from the first
3318 * to the end of the list of objects are relocated. Returns 0 on success,
3322 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
3323 int flags, RtldLockState *lockstate)
3328 for (error = 0, obj = first; obj != NULL;
3329 obj = TAILQ_NEXT(obj, next)) {
3332 error = relocate_object(obj, bind_now, rtldobj, flags,
3341 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3342 * referencing STT_GNU_IFUNC symbols is postponed till the other
3343 * relocations are done. The indirect functions specified as
3344 * ifunc are allowed to call other symbols, so we need to have
3345 * objects relocated before asking for resolution from indirects.
3347 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3348 * instead of the usual lazy handling of PLT slots. It is
3349 * consistent with how GNU does it.
3352 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3353 RtldLockState *lockstate)
3356 if (obj->ifuncs_resolved)
3358 obj->ifuncs_resolved = true;
3359 if (!obj->irelative && !obj->irelative_nonplt &&
3360 !((obj->bind_now || bind_now) && obj->gnu_ifunc) &&
3361 !obj->non_plt_gnu_ifunc)
3363 if (obj_disable_relro(obj) == -1 ||
3364 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3365 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj,
3366 lockstate) == -1) ||
3367 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3368 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3369 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld,
3370 flags | SYMLOOK_IFUNC, lockstate) == -1) ||
3371 obj_enforce_relro(obj) == -1)
3377 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3378 RtldLockState *lockstate)
3383 STAILQ_FOREACH(elm, list, link) {
3387 if (resolve_object_ifunc(obj, bind_now, flags,
3395 * Cleanup procedure. It will be called (by the atexit mechanism) just
3396 * before the process exits.
3401 RtldLockState lockstate;
3403 wlock_acquire(rtld_bind_lock, &lockstate);
3405 objlist_call_fini(&list_fini, NULL, &lockstate);
3406 /* No need to remove the items from the list, since we are exiting. */
3407 if (!libmap_disable)
3409 lock_release(rtld_bind_lock, &lockstate);
3418 * Iterate over a search path, translate each element, and invoke the
3419 * callback on the result.
3422 path_enumerate(const char *path, path_enum_proc callback,
3423 const char *refobj_path, void *arg)
3429 path += strspn(path, ":;");
3430 while (*path != '\0') {
3434 len = strcspn(path, ":;");
3435 trans = lm_findn(refobj_path, path, len);
3437 res = callback(trans, strlen(trans), arg);
3439 res = callback(path, len, arg);
3445 path += strspn(path, ":;");
3451 struct try_library_args {
3460 try_library_path(const char *dir, size_t dirlen, void *param)
3462 struct try_library_args *arg;
3466 if (*dir == '/' || trust) {
3469 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3472 pathname = arg->buffer;
3473 strncpy(pathname, dir, dirlen);
3474 pathname[dirlen] = '/';
3475 strcpy(pathname + dirlen + 1, arg->name);
3477 dbg(" Trying \"%s\"", pathname);
3478 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3480 dbg(" Opened \"%s\", fd %d", pathname, fd);
3481 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3482 strcpy(pathname, arg->buffer);
3486 dbg(" Failed to open \"%s\": %s",
3487 pathname, rtld_strerror(errno));
3494 search_library_path(const char *name, const char *path,
3495 const char *refobj_path, int *fdp)
3498 struct try_library_args arg;
3504 arg.namelen = strlen(name);
3505 arg.buffer = xmalloc(PATH_MAX);
3506 arg.buflen = PATH_MAX;
3509 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3519 * Finds the library with the given name using the directory descriptors
3520 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3522 * Returns a freshly-opened close-on-exec file descriptor for the library,
3523 * or -1 if the library cannot be found.
3526 search_library_pathfds(const char *name, const char *path, int *fdp)
3528 char *envcopy, *fdstr, *found, *last_token;
3532 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3534 /* Don't load from user-specified libdirs into setuid binaries. */
3538 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3542 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3543 if (name[0] == '/') {
3544 dbg("Absolute path (%s) passed to %s", name, __func__);
3549 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3550 * copy of the path, as strtok_r rewrites separator tokens
3554 envcopy = xstrdup(path);
3555 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3556 fdstr = strtok_r(NULL, ":", &last_token)) {
3557 dirfd = parse_integer(fdstr);
3559 _rtld_error("failed to parse directory FD: '%s'",
3563 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3566 len = strlen(fdstr) + strlen(name) + 3;
3567 found = xmalloc(len);
3568 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3569 _rtld_error("error generating '%d/%s'",
3573 dbg("open('%s') => %d", found, fd);
3584 dlclose(void *handle)
3586 RtldLockState lockstate;
3589 wlock_acquire(rtld_bind_lock, &lockstate);
3590 error = dlclose_locked(handle, &lockstate);
3591 lock_release(rtld_bind_lock, &lockstate);
3596 dlclose_locked(void *handle, RtldLockState *lockstate)
3600 root = dlcheck(handle);
3603 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3606 /* Unreference the object and its dependencies. */
3607 root->dl_refcount--;
3609 if (root->refcount == 1) {
3611 * The object will be no longer referenced, so we must unload it.
3612 * First, call the fini functions.
3614 objlist_call_fini(&list_fini, root, lockstate);
3618 /* Finish cleaning up the newly-unreferenced objects. */
3619 GDB_STATE(RT_DELETE,&root->linkmap);
3620 unload_object(root, lockstate);
3621 GDB_STATE(RT_CONSISTENT,NULL);
3625 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3632 if (*(lockinfo.dlerror_seen()) != 0)
3634 *lockinfo.dlerror_seen() = 1;
3635 return (lockinfo.dlerror_loc());
3639 * This function is deprecated and has no effect.
3642 dllockinit(void *context,
3643 void *(*_lock_create)(void *context) __unused,
3644 void (*_rlock_acquire)(void *lock) __unused,
3645 void (*_wlock_acquire)(void *lock) __unused,
3646 void (*_lock_release)(void *lock) __unused,
3647 void (*_lock_destroy)(void *lock) __unused,
3648 void (*context_destroy)(void *context))
3650 static void *cur_context;
3651 static void (*cur_context_destroy)(void *);
3653 /* Just destroy the context from the previous call, if necessary. */
3654 if (cur_context_destroy != NULL)
3655 cur_context_destroy(cur_context);
3656 cur_context = context;
3657 cur_context_destroy = context_destroy;
3661 dlopen(const char *name, int mode)
3664 return (rtld_dlopen(name, -1, mode));
3668 fdlopen(int fd, int mode)
3671 return (rtld_dlopen(NULL, fd, mode));
3675 rtld_dlopen(const char *name, int fd, int mode)
3677 RtldLockState lockstate;
3680 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3681 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3682 if (ld_tracing != NULL) {
3683 rlock_acquire(rtld_bind_lock, &lockstate);
3684 if (sigsetjmp(lockstate.env, 0) != 0)
3685 lock_upgrade(rtld_bind_lock, &lockstate);
3686 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3687 lock_release(rtld_bind_lock, &lockstate);
3689 lo_flags = RTLD_LO_DLOPEN;
3690 if (mode & RTLD_NODELETE)
3691 lo_flags |= RTLD_LO_NODELETE;
3692 if (mode & RTLD_NOLOAD)
3693 lo_flags |= RTLD_LO_NOLOAD;
3694 if (mode & RTLD_DEEPBIND)
3695 lo_flags |= RTLD_LO_DEEPBIND;
3696 if (ld_tracing != NULL)
3697 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3699 return (dlopen_object(name, fd, obj_main, lo_flags,
3700 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3704 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3709 if (obj->refcount == 0)
3710 unload_object(obj, lockstate);
3714 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3715 int mode, RtldLockState *lockstate)
3717 Obj_Entry *old_obj_tail;
3720 RtldLockState mlockstate;
3723 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x",
3724 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" :
3725 refobj->path, lo_flags, mode);
3726 objlist_init(&initlist);
3728 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3729 wlock_acquire(rtld_bind_lock, &mlockstate);
3730 lockstate = &mlockstate;
3732 GDB_STATE(RT_ADD,NULL);
3734 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3736 if (name == NULL && fd == -1) {
3740 obj = load_object(name, fd, refobj, lo_flags);
3745 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3746 objlist_push_tail(&list_global, obj);
3747 if (globallist_next(old_obj_tail) != NULL) {
3748 /* We loaded something new. */
3749 assert(globallist_next(old_obj_tail) == obj);
3750 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
3751 obj->symbolic = true;
3753 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 &&
3754 obj->static_tls && !allocate_tls_offset(obj)) {
3755 _rtld_error("%s: No space available "
3756 "for static Thread Local Storage", obj->path);
3760 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3761 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE));
3765 result = rtld_verify_versions(&obj->dagmembers);
3766 if (result != -1 && ld_tracing)
3768 if (result == -1 || relocate_object_dag(obj,
3769 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3770 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3772 dlopen_cleanup(obj, lockstate);
3774 } else if (lo_flags & RTLD_LO_EARLY) {
3776 * Do not call the init functions for early loaded
3777 * filtees. The image is still not initialized enough
3780 * Our object is found by the global object list and
3781 * will be ordered among all init calls done right
3782 * before transferring control to main.
3785 /* Make list of init functions to call. */
3786 initlist_add_objects(obj, obj, &initlist);
3789 * Process all no_delete or global objects here, given
3790 * them own DAGs to prevent their dependencies from being
3791 * unloaded. This has to be done after we have loaded all
3792 * of the dependencies, so that we do not miss any.
3798 * Bump the reference counts for objects on this DAG. If
3799 * this is the first dlopen() call for the object that was
3800 * already loaded as a dependency, initialize the dag
3806 if ((lo_flags & RTLD_LO_TRACE) != 0)
3809 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3810 obj->z_nodelete) && !obj->ref_nodel) {
3811 dbg("obj %s nodelete", obj->path);
3813 obj->z_nodelete = obj->ref_nodel = true;
3817 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3819 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3821 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3822 map_stacks_exec(lockstate);
3824 distribute_static_tls(&initlist, lockstate);
3827 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3828 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3830 objlist_clear(&initlist);
3831 dlopen_cleanup(obj, lockstate);
3832 if (lockstate == &mlockstate)
3833 lock_release(rtld_bind_lock, lockstate);
3837 if (!(lo_flags & RTLD_LO_EARLY)) {
3838 /* Call the init functions. */
3839 objlist_call_init(&initlist, lockstate);
3841 objlist_clear(&initlist);
3842 if (lockstate == &mlockstate)
3843 lock_release(rtld_bind_lock, lockstate);
3846 trace_loaded_objects(obj, false);
3847 if (lockstate == &mlockstate)
3848 lock_release(rtld_bind_lock, lockstate);
3853 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3857 const Obj_Entry *obj, *defobj;
3860 RtldLockState lockstate;
3867 symlook_init(&req, name);
3869 req.flags = flags | SYMLOOK_IN_PLT;
3870 req.lockstate = &lockstate;
3872 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3873 rlock_acquire(rtld_bind_lock, &lockstate);
3874 if (sigsetjmp(lockstate.env, 0) != 0)
3875 lock_upgrade(rtld_bind_lock, &lockstate);
3876 if (handle == NULL || handle == RTLD_NEXT ||
3877 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3879 if ((obj = obj_from_addr(retaddr)) == NULL) {
3880 _rtld_error("Cannot determine caller's shared object");
3881 lock_release(rtld_bind_lock, &lockstate);
3882 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3885 if (handle == NULL) { /* Just the caller's shared object. */
3886 res = symlook_obj(&req, obj);
3889 defobj = req.defobj_out;
3891 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3892 handle == RTLD_SELF) { /* ... caller included */
3893 if (handle == RTLD_NEXT)
3894 obj = globallist_next(obj);
3895 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3898 res = symlook_obj(&req, obj);
3900 if (def == NULL || (ld_dynamic_weak &&
3901 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK)) {
3903 defobj = req.defobj_out;
3904 if (!ld_dynamic_weak ||
3905 ELF_ST_BIND(def->st_info) != STB_WEAK)
3911 * Search the dynamic linker itself, and possibly resolve the
3912 * symbol from there. This is how the application links to
3913 * dynamic linker services such as dlopen.
3914 * Note that we ignore ld_dynamic_weak == false case,
3915 * always overriding weak symbols by rtld definitions.
3917 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3918 res = symlook_obj(&req, &obj_rtld);
3921 defobj = req.defobj_out;
3925 assert(handle == RTLD_DEFAULT);
3926 res = symlook_default(&req, obj);
3928 defobj = req.defobj_out;
3933 if ((obj = dlcheck(handle)) == NULL) {
3934 lock_release(rtld_bind_lock, &lockstate);
3935 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3939 donelist_init(&donelist);
3940 if (obj->mainprog) {
3941 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3942 res = symlook_global(&req, &donelist);
3945 defobj = req.defobj_out;
3948 * Search the dynamic linker itself, and possibly resolve the
3949 * symbol from there. This is how the application links to
3950 * dynamic linker services such as dlopen.
3952 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3953 res = symlook_obj(&req, &obj_rtld);
3956 defobj = req.defobj_out;
3961 /* Search the whole DAG rooted at the given object. */
3962 res = symlook_list(&req, &obj->dagmembers, &donelist);
3965 defobj = req.defobj_out;
3971 lock_release(rtld_bind_lock, &lockstate);
3974 * The value required by the caller is derived from the value
3975 * of the symbol. this is simply the relocated value of the
3978 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3979 sym = make_function_pointer(def, defobj);
3980 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3981 sym = rtld_resolve_ifunc(defobj, def);
3982 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3983 ti.ti_module = defobj->tlsindex;
3984 ti.ti_offset = def->st_value;
3985 sym = __tls_get_addr(&ti);
3987 sym = defobj->relocbase + def->st_value;
3988 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3992 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3993 ve != NULL ? ve->name : "");
3994 lock_release(rtld_bind_lock, &lockstate);
3995 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
4000 dlsym(void *handle, const char *name)
4002 return (do_dlsym(handle, name, __builtin_return_address(0), NULL,
4007 dlfunc(void *handle, const char *name)
4014 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
4020 dlvsym(void *handle, const char *name, const char *version)
4024 ventry.name = version;
4026 ventry.hash = elf_hash(version);
4028 return (do_dlsym(handle, name, __builtin_return_address(0), &ventry,
4033 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
4035 const Obj_Entry *obj;
4036 RtldLockState lockstate;
4038 rlock_acquire(rtld_bind_lock, &lockstate);
4039 obj = obj_from_addr(addr);
4041 _rtld_error("No shared object contains address");
4042 lock_release(rtld_bind_lock, &lockstate);
4045 rtld_fill_dl_phdr_info(obj, phdr_info);
4046 lock_release(rtld_bind_lock, &lockstate);
4051 dladdr(const void *addr, Dl_info *info)
4053 const Obj_Entry *obj;
4056 unsigned long symoffset;
4057 RtldLockState lockstate;
4059 rlock_acquire(rtld_bind_lock, &lockstate);
4060 obj = obj_from_addr(addr);
4062 _rtld_error("No shared object contains address");
4063 lock_release(rtld_bind_lock, &lockstate);
4066 info->dli_fname = obj->path;
4067 info->dli_fbase = obj->mapbase;
4068 info->dli_saddr = (void *)0;
4069 info->dli_sname = NULL;
4072 * Walk the symbol list looking for the symbol whose address is
4073 * closest to the address sent in.
4075 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
4076 def = obj->symtab + symoffset;
4079 * For skip the symbol if st_shndx is either SHN_UNDEF or
4082 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
4086 * If the symbol is greater than the specified address, or if it
4087 * is further away from addr than the current nearest symbol,
4090 symbol_addr = obj->relocbase + def->st_value;
4091 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
4094 /* Update our idea of the nearest symbol. */
4095 info->dli_sname = obj->strtab + def->st_name;
4096 info->dli_saddr = symbol_addr;
4099 if (info->dli_saddr == addr)
4102 lock_release(rtld_bind_lock, &lockstate);
4107 dlinfo(void *handle, int request, void *p)
4109 const Obj_Entry *obj;
4110 RtldLockState lockstate;
4113 rlock_acquire(rtld_bind_lock, &lockstate);
4115 if (handle == NULL || handle == RTLD_SELF) {
4118 retaddr = __builtin_return_address(0); /* __GNUC__ only */
4119 if ((obj = obj_from_addr(retaddr)) == NULL)
4120 _rtld_error("Cannot determine caller's shared object");
4122 obj = dlcheck(handle);
4125 lock_release(rtld_bind_lock, &lockstate);
4131 case RTLD_DI_LINKMAP:
4132 *((struct link_map const **)p) = &obj->linkmap;
4134 case RTLD_DI_ORIGIN:
4135 error = rtld_dirname(obj->path, p);
4138 case RTLD_DI_SERINFOSIZE:
4139 case RTLD_DI_SERINFO:
4140 error = do_search_info(obj, request, (struct dl_serinfo *)p);
4144 _rtld_error("Invalid request %d passed to dlinfo()", request);
4148 lock_release(rtld_bind_lock, &lockstate);
4154 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
4158 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
4159 phdr_info->dlpi_name = obj->path;
4160 phdr_info->dlpi_phdr = obj->phdr;
4161 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
4162 phdr_info->dlpi_tls_modid = obj->tlsindex;
4163 dtvp = &_tcb_get()->tcb_dtv;
4164 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp,
4165 obj->tlsindex, 0, true) + TLS_DTV_OFFSET;
4166 phdr_info->dlpi_adds = obj_loads;
4167 phdr_info->dlpi_subs = obj_loads - obj_count;
4171 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
4173 struct dl_phdr_info phdr_info;
4174 Obj_Entry *obj, marker;
4175 RtldLockState bind_lockstate, phdr_lockstate;
4178 init_marker(&marker);
4181 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
4182 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4183 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
4184 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
4185 rtld_fill_dl_phdr_info(obj, &phdr_info);
4187 lock_release(rtld_bind_lock, &bind_lockstate);
4189 error = callback(&phdr_info, sizeof phdr_info, param);
4191 wlock_acquire(rtld_bind_lock, &bind_lockstate);
4193 obj = globallist_next(&marker);
4194 TAILQ_REMOVE(&obj_list, &marker, next);
4196 lock_release(rtld_bind_lock, &bind_lockstate);
4197 lock_release(rtld_phdr_lock, &phdr_lockstate);
4203 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
4204 lock_release(rtld_bind_lock, &bind_lockstate);
4205 error = callback(&phdr_info, sizeof(phdr_info), param);
4207 lock_release(rtld_phdr_lock, &phdr_lockstate);
4212 fill_search_info(const char *dir, size_t dirlen, void *param)
4214 struct fill_search_info_args *arg;
4218 if (arg->request == RTLD_DI_SERINFOSIZE) {
4219 arg->serinfo->dls_cnt ++;
4220 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
4222 struct dl_serpath *s_entry;
4224 s_entry = arg->serpath;
4225 s_entry->dls_name = arg->strspace;
4226 s_entry->dls_flags = arg->flags;
4228 strncpy(arg->strspace, dir, dirlen);
4229 arg->strspace[dirlen] = '\0';
4231 arg->strspace += dirlen + 1;
4239 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
4241 struct dl_serinfo _info;
4242 struct fill_search_info_args args;
4244 args.request = RTLD_DI_SERINFOSIZE;
4245 args.serinfo = &_info;
4247 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
4250 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
4251 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
4252 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
4253 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
4254 if (!obj->z_nodeflib)
4255 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
4258 if (request == RTLD_DI_SERINFOSIZE) {
4259 info->dls_size = _info.dls_size;
4260 info->dls_cnt = _info.dls_cnt;
4264 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
4265 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
4269 args.request = RTLD_DI_SERINFO;
4270 args.serinfo = info;
4271 args.serpath = &info->dls_serpath[0];
4272 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
4274 args.flags = LA_SER_RUNPATH;
4275 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
4278 args.flags = LA_SER_LIBPATH;
4279 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
4282 args.flags = LA_SER_RUNPATH;
4283 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
4286 args.flags = LA_SER_CONFIG;
4287 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
4291 args.flags = LA_SER_DEFAULT;
4292 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
4293 fill_search_info, NULL, &args) != NULL)
4299 rtld_dirname(const char *path, char *bname)
4303 /* Empty or NULL string gets treated as "." */
4304 if (path == NULL || *path == '\0') {
4310 /* Strip trailing slashes */
4311 endp = path + strlen(path) - 1;
4312 while (endp > path && *endp == '/')
4315 /* Find the start of the dir */
4316 while (endp > path && *endp != '/')
4319 /* Either the dir is "/" or there are no slashes */
4321 bname[0] = *endp == '/' ? '/' : '.';
4327 } while (endp > path && *endp == '/');
4330 if (endp - path + 2 > PATH_MAX)
4332 _rtld_error("Filename is too long: %s", path);
4336 strncpy(bname, path, endp - path + 1);
4337 bname[endp - path + 1] = '\0';
4342 rtld_dirname_abs(const char *path, char *base)
4346 if (realpath(path, base) == NULL) {
4347 _rtld_error("realpath \"%s\" failed (%s)", path,
4348 rtld_strerror(errno));
4351 dbg("%s -> %s", path, base);
4352 last = strrchr(base, '/');
4354 _rtld_error("non-abs result from realpath \"%s\"", path);
4363 linkmap_add(Obj_Entry *obj)
4365 struct link_map *l, *prev;
4368 l->l_name = obj->path;
4369 l->l_base = obj->mapbase;
4370 l->l_ld = obj->dynamic;
4371 l->l_addr = obj->relocbase;
4373 if (r_debug.r_map == NULL) {
4379 * Scan to the end of the list, but not past the entry for the
4380 * dynamic linker, which we want to keep at the very end.
4382 for (prev = r_debug.r_map;
4383 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4384 prev = prev->l_next)
4387 /* Link in the new entry. */
4389 l->l_next = prev->l_next;
4390 if (l->l_next != NULL)
4391 l->l_next->l_prev = l;
4396 linkmap_delete(Obj_Entry *obj)
4401 if (l->l_prev == NULL) {
4402 if ((r_debug.r_map = l->l_next) != NULL)
4403 l->l_next->l_prev = NULL;
4407 if ((l->l_prev->l_next = l->l_next) != NULL)
4408 l->l_next->l_prev = l->l_prev;
4412 * Function for the debugger to set a breakpoint on to gain control.
4414 * The two parameters allow the debugger to easily find and determine
4415 * what the runtime loader is doing and to whom it is doing it.
4417 * When the loadhook trap is hit (r_debug_state, set at program
4418 * initialization), the arguments can be found on the stack:
4420 * +8 struct link_map *m
4421 * +4 struct r_debug *rd
4425 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4428 * The following is a hack to force the compiler to emit calls to
4429 * this function, even when optimizing. If the function is empty,
4430 * the compiler is not obliged to emit any code for calls to it,
4431 * even when marked __noinline. However, gdb depends on those
4434 __compiler_membar();
4438 * A function called after init routines have completed. This can be used to
4439 * break before a program's entry routine is called, and can be used when
4440 * main is not available in the symbol table.
4443 _r_debug_postinit(struct link_map *m __unused)
4446 /* See r_debug_state(). */
4447 __compiler_membar();
4451 release_object(Obj_Entry *obj)
4454 if (obj->holdcount > 0) {
4455 obj->unholdfree = true;
4458 munmap(obj->mapbase, obj->mapsize);
4459 linkmap_delete(obj);
4464 * Get address of the pointer variable in the main program.
4465 * Prefer non-weak symbol over the weak one.
4467 static const void **
4468 get_program_var_addr(const char *name, RtldLockState *lockstate)
4473 symlook_init(&req, name);
4474 req.lockstate = lockstate;
4475 donelist_init(&donelist);
4476 if (symlook_global(&req, &donelist) != 0)
4478 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4479 return ((const void **)make_function_pointer(req.sym_out,
4481 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4482 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4484 return ((const void **)(req.defobj_out->relocbase +
4485 req.sym_out->st_value));
4489 * Set a pointer variable in the main program to the given value. This
4490 * is used to set key variables such as "environ" before any of the
4491 * init functions are called.
4494 set_program_var(const char *name, const void *value)
4498 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4499 dbg("\"%s\": *%p <-- %p", name, addr, value);
4505 * Search the global objects, including dependencies and main object,
4506 * for the given symbol.
4509 symlook_global(SymLook *req, DoneList *donelist)
4512 const Objlist_Entry *elm;
4515 symlook_init_from_req(&req1, req);
4517 /* Search all objects loaded at program start up. */
4518 if (req->defobj_out == NULL || (ld_dynamic_weak &&
4519 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) {
4520 res = symlook_list(&req1, &list_main, donelist);
4521 if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL ||
4522 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4523 req->sym_out = req1.sym_out;
4524 req->defobj_out = req1.defobj_out;
4525 assert(req->defobj_out != NULL);
4529 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4530 STAILQ_FOREACH(elm, &list_global, link) {
4531 if (req->defobj_out != NULL && (!ld_dynamic_weak ||
4532 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4534 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4535 if (res == 0 && (req->defobj_out == NULL ||
4536 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4537 req->sym_out = req1.sym_out;
4538 req->defobj_out = req1.defobj_out;
4539 assert(req->defobj_out != NULL);
4543 return (req->sym_out != NULL ? 0 : ESRCH);
4547 * Given a symbol name in a referencing object, find the corresponding
4548 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4549 * no definition was found. Returns a pointer to the Obj_Entry of the
4550 * defining object via the reference parameter DEFOBJ_OUT.
4553 symlook_default(SymLook *req, const Obj_Entry *refobj)
4556 const Objlist_Entry *elm;
4560 donelist_init(&donelist);
4561 symlook_init_from_req(&req1, req);
4564 * Look first in the referencing object if linked symbolically,
4565 * and similarly handle protected symbols.
4567 res = symlook_obj(&req1, refobj);
4568 if (res == 0 && (refobj->symbolic ||
4569 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4570 req->sym_out = req1.sym_out;
4571 req->defobj_out = req1.defobj_out;
4572 assert(req->defobj_out != NULL);
4574 if (refobj->symbolic || req->defobj_out != NULL)
4575 donelist_check(&donelist, refobj);
4577 symlook_global(req, &donelist);
4579 /* Search all dlopened DAGs containing the referencing object. */
4580 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4581 if (req->sym_out != NULL && (!ld_dynamic_weak ||
4582 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK))
4584 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4585 if (res == 0 && (req->sym_out == NULL ||
4586 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4587 req->sym_out = req1.sym_out;
4588 req->defobj_out = req1.defobj_out;
4589 assert(req->defobj_out != NULL);
4594 * Search the dynamic linker itself, and possibly resolve the
4595 * symbol from there. This is how the application links to
4596 * dynamic linker services such as dlopen.
4598 if (req->sym_out == NULL ||
4599 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4600 res = symlook_obj(&req1, &obj_rtld);
4602 req->sym_out = req1.sym_out;
4603 req->defobj_out = req1.defobj_out;
4604 assert(req->defobj_out != NULL);
4608 return (req->sym_out != NULL ? 0 : ESRCH);
4612 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4615 const Obj_Entry *defobj;
4616 const Objlist_Entry *elm;
4622 STAILQ_FOREACH(elm, objlist, link) {
4623 if (donelist_check(dlp, elm->obj))
4625 symlook_init_from_req(&req1, req);
4626 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4627 if (def == NULL || (ld_dynamic_weak &&
4628 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4630 defobj = req1.defobj_out;
4631 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK)
4638 req->defobj_out = defobj;
4645 * Search the chain of DAGS cointed to by the given Needed_Entry
4646 * for a symbol of the given name. Each DAG is scanned completely
4647 * before advancing to the next one. Returns a pointer to the symbol,
4648 * or NULL if no definition was found.
4651 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4654 const Needed_Entry *n;
4655 const Obj_Entry *defobj;
4661 symlook_init_from_req(&req1, req);
4662 for (n = needed; n != NULL; n = n->next) {
4663 if (n->obj == NULL ||
4664 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4666 if (def == NULL || (ld_dynamic_weak &&
4667 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4669 defobj = req1.defobj_out;
4670 if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK)
4676 req->defobj_out = defobj;
4683 * Search the symbol table of a single shared object for a symbol of
4684 * the given name and version, if requested. Returns a pointer to the
4685 * symbol, or NULL if no definition was found. If the object is
4686 * filter, return filtered symbol from filtee.
4688 * The symbol's hash value is passed in for efficiency reasons; that
4689 * eliminates many recomputations of the hash value.
4692 symlook_obj(SymLook *req, const Obj_Entry *obj)
4696 int flags, res, mres;
4699 * If there is at least one valid hash at this point, we prefer to
4700 * use the faster GNU version if available.
4702 if (obj->valid_hash_gnu)
4703 mres = symlook_obj1_gnu(req, obj);
4704 else if (obj->valid_hash_sysv)
4705 mres = symlook_obj1_sysv(req, obj);
4710 if (obj->needed_filtees != NULL) {
4711 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4712 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4713 donelist_init(&donelist);
4714 symlook_init_from_req(&req1, req);
4715 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4717 req->sym_out = req1.sym_out;
4718 req->defobj_out = req1.defobj_out;
4722 if (obj->needed_aux_filtees != NULL) {
4723 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4724 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4725 donelist_init(&donelist);
4726 symlook_init_from_req(&req1, req);
4727 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4729 req->sym_out = req1.sym_out;
4730 req->defobj_out = req1.defobj_out;
4738 /* Symbol match routine common to both hash functions */
4740 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4741 const unsigned long symnum)
4744 const Elf_Sym *symp;
4747 symp = obj->symtab + symnum;
4748 strp = obj->strtab + symp->st_name;
4750 switch (ELF_ST_TYPE(symp->st_info)) {
4756 if (symp->st_value == 0)
4760 if (symp->st_shndx != SHN_UNDEF)
4762 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4763 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4769 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4772 if (req->ventry == NULL) {
4773 if (obj->versyms != NULL) {
4774 verndx = VER_NDX(obj->versyms[symnum]);
4775 if (verndx > obj->vernum) {
4777 "%s: symbol %s references wrong version %d",
4778 obj->path, obj->strtab + symnum, verndx);
4782 * If we are not called from dlsym (i.e. this
4783 * is a normal relocation from unversioned
4784 * binary), accept the symbol immediately if
4785 * it happens to have first version after this
4786 * shared object became versioned. Otherwise,
4787 * if symbol is versioned and not hidden,
4788 * remember it. If it is the only symbol with
4789 * this name exported by the shared object, it
4790 * will be returned as a match by the calling
4791 * function. If symbol is global (verndx < 2)
4792 * accept it unconditionally.
4794 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4795 verndx == VER_NDX_GIVEN) {
4796 result->sym_out = symp;
4799 else if (verndx >= VER_NDX_GIVEN) {
4800 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4802 if (result->vsymp == NULL)
4803 result->vsymp = symp;
4809 result->sym_out = symp;
4812 if (obj->versyms == NULL) {
4813 if (object_match_name(obj, req->ventry->name)) {
4814 _rtld_error("%s: object %s should provide version %s "
4815 "for symbol %s", obj_rtld.path, obj->path,
4816 req->ventry->name, obj->strtab + symnum);
4820 verndx = VER_NDX(obj->versyms[symnum]);
4821 if (verndx > obj->vernum) {
4822 _rtld_error("%s: symbol %s references wrong version %d",
4823 obj->path, obj->strtab + symnum, verndx);
4826 if (obj->vertab[verndx].hash != req->ventry->hash ||
4827 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4829 * Version does not match. Look if this is a
4830 * global symbol and if it is not hidden. If
4831 * global symbol (verndx < 2) is available,
4832 * use it. Do not return symbol if we are
4833 * called by dlvsym, because dlvsym looks for
4834 * a specific version and default one is not
4835 * what dlvsym wants.
4837 if ((req->flags & SYMLOOK_DLSYM) ||
4838 (verndx >= VER_NDX_GIVEN) ||
4839 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4843 result->sym_out = symp;
4848 * Search for symbol using SysV hash function.
4849 * obj->buckets is known not to be NULL at this point; the test for this was
4850 * performed with the obj->valid_hash_sysv assignment.
4853 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4855 unsigned long symnum;
4856 Sym_Match_Result matchres;
4858 matchres.sym_out = NULL;
4859 matchres.vsymp = NULL;
4860 matchres.vcount = 0;
4862 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4863 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4864 if (symnum >= obj->nchains)
4865 return (ESRCH); /* Bad object */
4867 if (matched_symbol(req, obj, &matchres, symnum)) {
4868 req->sym_out = matchres.sym_out;
4869 req->defobj_out = obj;
4873 if (matchres.vcount == 1) {
4874 req->sym_out = matchres.vsymp;
4875 req->defobj_out = obj;
4881 /* Search for symbol using GNU hash function */
4883 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4885 Elf_Addr bloom_word;
4886 const Elf32_Word *hashval;
4888 Sym_Match_Result matchres;
4889 unsigned int h1, h2;
4890 unsigned long symnum;
4892 matchres.sym_out = NULL;
4893 matchres.vsymp = NULL;
4894 matchres.vcount = 0;
4896 /* Pick right bitmask word from Bloom filter array */
4897 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4898 obj->maskwords_bm_gnu];
4900 /* Calculate modulus word size of gnu hash and its derivative */
4901 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4902 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4904 /* Filter out the "definitely not in set" queries */
4905 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4908 /* Locate hash chain and corresponding value element*/
4909 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4912 hashval = &obj->chain_zero_gnu[bucket];
4914 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4915 symnum = hashval - obj->chain_zero_gnu;
4916 if (matched_symbol(req, obj, &matchres, symnum)) {
4917 req->sym_out = matchres.sym_out;
4918 req->defobj_out = obj;
4922 } while ((*hashval++ & 1) == 0);
4923 if (matchres.vcount == 1) {
4924 req->sym_out = matchres.vsymp;
4925 req->defobj_out = obj;
4932 trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2)
4934 *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME);
4935 if (*main_local == NULL)
4938 *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1);
4940 *fmt1 = "\t%o => %p (%x)\n";
4942 *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2);
4944 *fmt2 = "\t%o (%x)\n";
4948 trace_print_obj(Obj_Entry *obj, const char *name, const char *path,
4949 const char *main_local, const char *fmt1, const char *fmt2)
4958 fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2;
4960 while ((c = *fmt++) != '\0') {
4986 rtld_putstr(main_local);
4989 rtld_putstr(obj_main->path);
4998 rtld_printf("%p", obj != NULL ?
4999 obj->mapbase : NULL);
5009 trace_loaded_objects(Obj_Entry *obj, bool show_preload)
5011 const char *fmt1, *fmt2, *main_local;
5012 const char *name, *path;
5013 bool first_spurious, list_containers;
5015 trace_calc_fmts(&main_local, &fmt1, &fmt2);
5016 list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL;
5018 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5019 Needed_Entry *needed;
5023 if (list_containers && obj->needed != NULL)
5024 rtld_printf("%s:\n", obj->path);
5025 for (needed = obj->needed; needed; needed = needed->next) {
5026 if (needed->obj != NULL) {
5027 if (needed->obj->traced && !list_containers)
5029 needed->obj->traced = true;
5030 path = needed->obj->path;
5034 name = obj->strtab + needed->name;
5035 trace_print_obj(needed->obj, name, path, main_local,
5041 if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL)
5042 fmt2 = "\t%p (%x)\n";
5043 first_spurious = true;
5045 TAILQ_FOREACH(obj, &obj_list, next) {
5046 if (obj->marker || obj == obj_main || obj->traced)
5049 if (list_containers && first_spurious) {
5050 rtld_printf("[preloaded]\n");
5051 first_spurious = false;
5054 Name_Entry *fname = STAILQ_FIRST(&obj->names);
5055 name = fname == NULL ? "<unknown>" : fname->name;
5056 trace_print_obj(obj, name, obj->path, main_local,
5063 * Unload a dlopened object and its dependencies from memory and from
5064 * our data structures. It is assumed that the DAG rooted in the
5065 * object has already been unreferenced, and that the object has a
5066 * reference count of 0.
5069 unload_object(Obj_Entry *root, RtldLockState *lockstate)
5071 Obj_Entry marker, *obj, *next;
5073 assert(root->refcount == 0);
5076 * Pass over the DAG removing unreferenced objects from
5077 * appropriate lists.
5079 unlink_object(root);
5081 /* Unmap all objects that are no longer referenced. */
5082 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
5083 next = TAILQ_NEXT(obj, next);
5084 if (obj->marker || obj->refcount != 0)
5086 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
5087 obj->mapsize, 0, obj->path);
5088 dbg("unloading \"%s\"", obj->path);
5090 * Unlink the object now to prevent new references from
5091 * being acquired while the bind lock is dropped in
5092 * recursive dlclose() invocations.
5094 TAILQ_REMOVE(&obj_list, obj, next);
5097 if (obj->filtees_loaded) {
5099 init_marker(&marker);
5100 TAILQ_INSERT_BEFORE(next, &marker, next);
5101 unload_filtees(obj, lockstate);
5102 next = TAILQ_NEXT(&marker, next);
5103 TAILQ_REMOVE(&obj_list, &marker, next);
5105 unload_filtees(obj, lockstate);
5107 release_object(obj);
5112 unlink_object(Obj_Entry *root)
5116 if (root->refcount == 0) {
5117 /* Remove the object from the RTLD_GLOBAL list. */
5118 objlist_remove(&list_global, root);
5120 /* Remove the object from all objects' DAG lists. */
5121 STAILQ_FOREACH(elm, &root->dagmembers, link) {
5122 objlist_remove(&elm->obj->dldags, root);
5123 if (elm->obj != root)
5124 unlink_object(elm->obj);
5130 ref_dag(Obj_Entry *root)
5134 assert(root->dag_inited);
5135 STAILQ_FOREACH(elm, &root->dagmembers, link)
5136 elm->obj->refcount++;
5140 unref_dag(Obj_Entry *root)
5144 assert(root->dag_inited);
5145 STAILQ_FOREACH(elm, &root->dagmembers, link)
5146 elm->obj->refcount--;
5150 * Common code for MD __tls_get_addr().
5153 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked)
5155 Elf_Addr *newdtv, *dtv;
5156 RtldLockState lockstate;
5160 /* Check dtv generation in case new modules have arrived */
5161 if (dtv[0] != tls_dtv_generation) {
5163 wlock_acquire(rtld_bind_lock, &lockstate);
5164 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
5166 if (to_copy > tls_max_index)
5167 to_copy = tls_max_index;
5168 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
5169 newdtv[0] = tls_dtv_generation;
5170 newdtv[1] = tls_max_index;
5173 lock_release(rtld_bind_lock, &lockstate);
5174 dtv = *dtvp = newdtv;
5177 /* Dynamically allocate module TLS if necessary */
5178 if (dtv[index + 1] == 0) {
5179 /* Signal safe, wlock will block out signals. */
5181 wlock_acquire(rtld_bind_lock, &lockstate);
5182 if (!dtv[index + 1])
5183 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
5185 lock_release(rtld_bind_lock, &lockstate);
5187 return ((void *)(dtv[index + 1] + offset));
5191 tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset)
5196 /* Check dtv generation in case new modules have arrived */
5197 if (__predict_true(dtv[0] == tls_dtv_generation &&
5198 dtv[index + 1] != 0))
5199 return ((void *)(dtv[index + 1] + offset));
5200 return (tls_get_addr_slow(dtvp, index, offset, false));
5203 #ifdef TLS_VARIANT_I
5206 * Return pointer to allocated TLS block
5209 get_tls_block_ptr(void *tcb, size_t tcbsize)
5211 size_t extra_size, post_size, pre_size, tls_block_size;
5212 size_t tls_init_align;
5214 tls_init_align = MAX(obj_main->tlsalign, 1);
5216 /* Compute fragments sizes. */
5217 extra_size = tcbsize - TLS_TCB_SIZE;
5218 post_size = calculate_tls_post_size(tls_init_align);
5219 tls_block_size = tcbsize + post_size;
5220 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5222 return ((char *)tcb - pre_size - extra_size);
5226 * Allocate Static TLS using the Variant I method.
5228 * For details on the layout, see lib/libc/gen/tls.c.
5230 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
5231 * it is based on tls_last_offset, and TLS offsets here are really TCB
5232 * offsets, whereas libc's tls_static_space is just the executable's static
5236 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
5240 Elf_Addr *dtv, **tcb;
5243 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
5244 size_t tls_init_align, tls_init_offset;
5246 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
5249 assert(tcbsize >= TLS_TCB_SIZE);
5250 maxalign = MAX(tcbalign, tls_static_max_align);
5251 tls_init_align = MAX(obj_main->tlsalign, 1);
5253 /* Compute fragmets sizes. */
5254 extra_size = tcbsize - TLS_TCB_SIZE;
5255 post_size = calculate_tls_post_size(tls_init_align);
5256 tls_block_size = tcbsize + post_size;
5257 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
5258 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
5260 /* Allocate whole TLS block */
5261 tls_block = malloc_aligned(tls_block_size, maxalign, 0);
5262 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
5264 if (oldtcb != NULL) {
5265 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
5267 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
5269 /* Adjust the DTV. */
5271 for (i = 0; i < dtv[1]; i++) {
5272 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
5273 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
5274 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
5278 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
5280 dtv[0] = tls_dtv_generation;
5281 dtv[1] = tls_max_index;
5283 for (obj = globallist_curr(objs); obj != NULL;
5284 obj = globallist_next(obj)) {
5285 if (obj->tlsoffset == 0)
5287 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
5288 addr = (Elf_Addr)tcb + obj->tlsoffset;
5289 if (tls_init_offset > 0)
5290 memset((void *)addr, 0, tls_init_offset);
5291 if (obj->tlsinitsize > 0) {
5292 memcpy((void *)(addr + tls_init_offset), obj->tlsinit,
5295 if (obj->tlssize > obj->tlsinitsize) {
5296 memset((void *)(addr + tls_init_offset + obj->tlsinitsize),
5297 0, obj->tlssize - obj->tlsinitsize - tls_init_offset);
5299 dtv[obj->tlsindex + 1] = addr;
5307 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
5310 Elf_Addr tlsstart, tlsend;
5312 size_t dtvsize, i, tls_init_align;
5314 assert(tcbsize >= TLS_TCB_SIZE);
5315 tls_init_align = MAX(obj_main->tlsalign, 1);
5317 /* Compute fragments sizes. */
5318 post_size = calculate_tls_post_size(tls_init_align);
5320 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
5321 tlsend = (Elf_Addr)tcb + tls_static_space;
5323 dtv = *(Elf_Addr **)tcb;
5325 for (i = 0; i < dtvsize; i++) {
5326 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
5327 free((void*)dtv[i+2]);
5331 free_aligned(get_tls_block_ptr(tcb, tcbsize));
5334 #endif /* TLS_VARIANT_I */
5336 #ifdef TLS_VARIANT_II
5339 * Allocate Static TLS using the Variant II method.
5342 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
5345 size_t size, ralign;
5347 Elf_Addr *dtv, *olddtv;
5348 Elf_Addr segbase, oldsegbase, addr;
5352 if (tls_static_max_align > ralign)
5353 ralign = tls_static_max_align;
5354 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
5356 assert(tcbsize >= 2*sizeof(Elf_Addr));
5357 tls = malloc_aligned(size, ralign, 0 /* XXX */);
5358 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
5360 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign));
5361 ((Elf_Addr *)segbase)[0] = segbase;
5362 ((Elf_Addr *)segbase)[1] = (Elf_Addr) dtv;
5364 dtv[0] = tls_dtv_generation;
5365 dtv[1] = tls_max_index;
5369 * Copy the static TLS block over whole.
5371 oldsegbase = (Elf_Addr) oldtls;
5372 memcpy((void *)(segbase - tls_static_space),
5373 (const void *)(oldsegbase - tls_static_space),
5377 * If any dynamic TLS blocks have been created tls_get_addr(),
5380 olddtv = ((Elf_Addr **)oldsegbase)[1];
5381 for (i = 0; i < olddtv[1]; i++) {
5382 if (olddtv[i + 2] < oldsegbase - size ||
5383 olddtv[i + 2] > oldsegbase) {
5384 dtv[i + 2] = olddtv[i + 2];
5390 * We assume that this block was the one we created with
5391 * allocate_initial_tls().
5393 free_tls(oldtls, 2 * sizeof(Elf_Addr), sizeof(Elf_Addr));
5395 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5396 if (obj->marker || obj->tlsoffset == 0)
5398 addr = segbase - obj->tlsoffset;
5399 memset((void *)(addr + obj->tlsinitsize),
5400 0, obj->tlssize - obj->tlsinitsize);
5402 memcpy((void *)addr, obj->tlsinit, obj->tlsinitsize);
5403 obj->static_tls_copied = true;
5405 dtv[obj->tlsindex + 1] = addr;
5409 return ((void *)segbase);
5413 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
5416 size_t size, ralign;
5418 Elf_Addr tlsstart, tlsend;
5421 * Figure out the size of the initial TLS block so that we can
5422 * find stuff which ___tls_get_addr() allocated dynamically.
5425 if (tls_static_max_align > ralign)
5426 ralign = tls_static_max_align;
5427 size = roundup(tls_static_space, ralign);
5429 dtv = ((Elf_Addr **)tls)[1];
5431 tlsend = (Elf_Addr)tls;
5432 tlsstart = tlsend - size;
5433 for (i = 0; i < dtvsize; i++) {
5434 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart ||
5435 dtv[i + 2] > tlsend)) {
5436 free_aligned((void *)dtv[i + 2]);
5440 free_aligned((void *)tlsstart);
5444 #endif /* TLS_VARIANT_II */
5447 * Allocate TLS block for module with given index.
5450 allocate_module_tls(int index)
5455 TAILQ_FOREACH(obj, &obj_list, next) {
5458 if (obj->tlsindex == index)
5462 _rtld_error("Can't find module with TLS index %d", index);
5466 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5467 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5468 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5473 allocate_tls_offset(Obj_Entry *obj)
5480 if (obj->tlssize == 0) {
5481 obj->tls_done = true;
5485 if (tls_last_offset == 0)
5486 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign,
5489 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5490 obj->tlssize, obj->tlsalign, obj->tlspoffset);
5492 obj->tlsoffset = off;
5493 #ifdef TLS_VARIANT_I
5494 off += obj->tlssize;
5498 * If we have already fixed the size of the static TLS block, we
5499 * must stay within that size. When allocating the static TLS, we
5500 * leave a small amount of space spare to be used for dynamically
5501 * loading modules which use static TLS.
5503 if (tls_static_space != 0) {
5504 if (off > tls_static_space)
5506 } else if (obj->tlsalign > tls_static_max_align) {
5507 tls_static_max_align = obj->tlsalign;
5510 tls_last_offset = off;
5511 tls_last_size = obj->tlssize;
5512 obj->tls_done = true;
5518 free_tls_offset(Obj_Entry *obj)
5522 * If we were the last thing to allocate out of the static TLS
5523 * block, we give our space back to the 'allocator'. This is a
5524 * simplistic workaround to allow libGL.so.1 to be loaded and
5525 * unloaded multiple times.
5527 size_t off = obj->tlsoffset;
5528 #ifdef TLS_VARIANT_I
5529 off += obj->tlssize;
5531 if (off == tls_last_offset) {
5532 tls_last_offset -= obj->tlssize;
5538 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5541 RtldLockState lockstate;
5543 wlock_acquire(rtld_bind_lock, &lockstate);
5544 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5546 lock_release(rtld_bind_lock, &lockstate);
5551 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5553 RtldLockState lockstate;
5555 wlock_acquire(rtld_bind_lock, &lockstate);
5556 free_tls(tcb, tcbsize, tcbalign);
5557 lock_release(rtld_bind_lock, &lockstate);
5561 object_add_name(Obj_Entry *obj, const char *name)
5567 entry = malloc(sizeof(Name_Entry) + len);
5569 if (entry != NULL) {
5570 strcpy(entry->name, name);
5571 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5576 object_match_name(const Obj_Entry *obj, const char *name)
5580 STAILQ_FOREACH(entry, &obj->names, link) {
5581 if (strcmp(name, entry->name) == 0)
5588 locate_dependency(const Obj_Entry *obj, const char *name)
5590 const Objlist_Entry *entry;
5591 const Needed_Entry *needed;
5593 STAILQ_FOREACH(entry, &list_main, link) {
5594 if (object_match_name(entry->obj, name))
5595 return (entry->obj);
5598 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5599 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5600 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5602 * If there is DT_NEEDED for the name we are looking for,
5603 * we are all set. Note that object might not be found if
5604 * dependency was not loaded yet, so the function can
5605 * return NULL here. This is expected and handled
5606 * properly by the caller.
5608 return (needed->obj);
5611 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5617 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5618 const Elf_Vernaux *vna)
5620 const Elf_Verdef *vd;
5621 const char *vername;
5623 vername = refobj->strtab + vna->vna_name;
5624 vd = depobj->verdef;
5626 _rtld_error("%s: version %s required by %s not defined",
5627 depobj->path, vername, refobj->path);
5631 if (vd->vd_version != VER_DEF_CURRENT) {
5632 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5633 depobj->path, vd->vd_version);
5636 if (vna->vna_hash == vd->vd_hash) {
5637 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5638 ((const char *)vd + vd->vd_aux);
5639 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5642 if (vd->vd_next == 0)
5644 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5646 if (vna->vna_flags & VER_FLG_WEAK)
5648 _rtld_error("%s: version %s required by %s not found",
5649 depobj->path, vername, refobj->path);
5654 rtld_verify_object_versions(Obj_Entry *obj)
5656 const Elf_Verneed *vn;
5657 const Elf_Verdef *vd;
5658 const Elf_Verdaux *vda;
5659 const Elf_Vernaux *vna;
5660 const Obj_Entry *depobj;
5661 int maxvernum, vernum;
5663 if (obj->ver_checked)
5665 obj->ver_checked = true;
5669 * Walk over defined and required version records and figure out
5670 * max index used by any of them. Do very basic sanity checking
5674 while (vn != NULL) {
5675 if (vn->vn_version != VER_NEED_CURRENT) {
5676 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5677 obj->path, vn->vn_version);
5680 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5682 vernum = VER_NEED_IDX(vna->vna_other);
5683 if (vernum > maxvernum)
5685 if (vna->vna_next == 0)
5687 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5689 if (vn->vn_next == 0)
5691 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5695 while (vd != NULL) {
5696 if (vd->vd_version != VER_DEF_CURRENT) {
5697 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5698 obj->path, vd->vd_version);
5701 vernum = VER_DEF_IDX(vd->vd_ndx);
5702 if (vernum > maxvernum)
5704 if (vd->vd_next == 0)
5706 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5713 * Store version information in array indexable by version index.
5714 * Verify that object version requirements are satisfied along the
5717 obj->vernum = maxvernum + 1;
5718 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5721 while (vd != NULL) {
5722 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5723 vernum = VER_DEF_IDX(vd->vd_ndx);
5724 assert(vernum <= maxvernum);
5725 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5726 obj->vertab[vernum].hash = vd->vd_hash;
5727 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5728 obj->vertab[vernum].file = NULL;
5729 obj->vertab[vernum].flags = 0;
5731 if (vd->vd_next == 0)
5733 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5737 while (vn != NULL) {
5738 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5741 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5743 if (check_object_provided_version(obj, depobj, vna))
5745 vernum = VER_NEED_IDX(vna->vna_other);
5746 assert(vernum <= maxvernum);
5747 obj->vertab[vernum].hash = vna->vna_hash;
5748 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5749 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5750 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5751 VER_INFO_HIDDEN : 0;
5752 if (vna->vna_next == 0)
5754 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5756 if (vn->vn_next == 0)
5758 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5764 rtld_verify_versions(const Objlist *objlist)
5766 Objlist_Entry *entry;
5770 STAILQ_FOREACH(entry, objlist, link) {
5772 * Skip dummy objects or objects that have their version requirements
5775 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5777 if (rtld_verify_object_versions(entry->obj) == -1) {
5779 if (ld_tracing == NULL)
5783 if (rc == 0 || ld_tracing != NULL)
5784 rc = rtld_verify_object_versions(&obj_rtld);
5789 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5794 vernum = VER_NDX(obj->versyms[symnum]);
5795 if (vernum >= obj->vernum) {
5796 _rtld_error("%s: symbol %s has wrong verneed value %d",
5797 obj->path, obj->strtab + symnum, vernum);
5798 } else if (obj->vertab[vernum].hash != 0) {
5799 return (&obj->vertab[vernum]);
5806 _rtld_get_stack_prot(void)
5809 return (stack_prot);
5813 _rtld_is_dlopened(void *arg)
5816 RtldLockState lockstate;
5819 rlock_acquire(rtld_bind_lock, &lockstate);
5822 obj = obj_from_addr(arg);
5824 _rtld_error("No shared object contains address");
5825 lock_release(rtld_bind_lock, &lockstate);
5828 res = obj->dlopened ? 1 : 0;
5829 lock_release(rtld_bind_lock, &lockstate);
5834 obj_remap_relro(Obj_Entry *obj, int prot)
5837 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5839 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5840 obj->path, prot, rtld_strerror(errno));
5847 obj_disable_relro(Obj_Entry *obj)
5850 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5854 obj_enforce_relro(Obj_Entry *obj)
5857 return (obj_remap_relro(obj, PROT_READ));
5861 map_stacks_exec(RtldLockState *lockstate)
5863 void (*thr_map_stacks_exec)(void);
5865 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5867 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5868 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5869 if (thr_map_stacks_exec != NULL) {
5870 stack_prot |= PROT_EXEC;
5871 thr_map_stacks_exec();
5876 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5880 void (*distrib)(size_t, void *, size_t, size_t);
5882 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5883 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5884 if (distrib == NULL)
5886 STAILQ_FOREACH(elm, list, link) {
5888 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5890 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5892 obj->static_tls_copied = true;
5897 symlook_init(SymLook *dst, const char *name)
5900 bzero(dst, sizeof(*dst));
5902 dst->hash = elf_hash(name);
5903 dst->hash_gnu = gnu_hash(name);
5907 symlook_init_from_req(SymLook *dst, const SymLook *src)
5910 dst->name = src->name;
5911 dst->hash = src->hash;
5912 dst->hash_gnu = src->hash_gnu;
5913 dst->ventry = src->ventry;
5914 dst->flags = src->flags;
5915 dst->defobj_out = NULL;
5916 dst->sym_out = NULL;
5917 dst->lockstate = src->lockstate;
5921 open_binary_fd(const char *argv0, bool search_in_path,
5922 const char **binpath_res)
5924 char *binpath, *pathenv, *pe, *res1;
5930 if (search_in_path && strchr(argv0, '/') == NULL) {
5931 binpath = xmalloc(PATH_MAX);
5932 pathenv = getenv("PATH");
5933 if (pathenv == NULL) {
5934 _rtld_error("-p and no PATH environment variable");
5937 pathenv = strdup(pathenv);
5938 if (pathenv == NULL) {
5939 _rtld_error("Cannot allocate memory");
5944 while ((pe = strsep(&pathenv, ":")) != NULL) {
5945 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
5947 if (binpath[0] != '\0' &&
5948 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
5950 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
5952 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5953 if (fd != -1 || errno != ENOENT) {
5960 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5965 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5968 if (res != NULL && res[0] != '/') {
5969 res1 = xmalloc(PATH_MAX);
5970 if (realpath(res, res1) != NULL) {
5972 free(__DECONST(char *, res));
5983 * Parse a set of command-line arguments.
5986 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
5987 const char **argv0, bool *dir_ignore)
5992 int arglen, fd, i, j, mib[2];
5994 bool seen_b, seen_f;
5996 dbg("Parsing command-line arguments");
5999 *dir_ignore = false;
6000 seen_b = seen_f = false;
6002 for (i = 1; i < argc; i++ ) {
6004 dbg("argv[%d]: '%s'", i, arg);
6007 * rtld arguments end with an explicit "--" or with the first
6008 * non-prefixed argument.
6010 if (strcmp(arg, "--") == 0) {
6018 * All other arguments are single-character options that can
6019 * be combined, so we need to search through `arg` for them.
6021 arglen = strlen(arg);
6022 for (j = 1; j < arglen; j++) {
6025 print_usage(argv[0]);
6027 } else if (opt == 'b') {
6029 _rtld_error("Both -b and -f specified");
6032 if (j != arglen - 1) {
6033 _rtld_error("Invalid options: %s", arg);
6040 } else if (opt == 'd') {
6042 } else if (opt == 'f') {
6044 _rtld_error("Both -b and -f specified");
6049 * -f XX can be used to specify a
6050 * descriptor for the binary named at
6051 * the command line (i.e., the later
6052 * argument will specify the process
6053 * name but the descriptor is what
6054 * will actually be executed).
6056 * -f must be the last option in the
6057 * group, e.g., -abcf <fd>.
6059 if (j != arglen - 1) {
6060 _rtld_error("Invalid options: %s", arg);
6064 fd = parse_integer(argv[i]);
6067 "Invalid file descriptor: '%s'",
6074 } else if (opt == 'p') {
6076 } else if (opt == 'u') {
6078 } else if (opt == 'v') {
6081 mib[1] = HW_MACHINE;
6082 sz = sizeof(machine);
6083 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
6084 ld_elf_hints_path = ld_get_env_var(
6086 set_ld_elf_hints_path();
6088 "FreeBSD ld-elf.so.1 %s\n"
6089 "FreeBSD_version %d\n"
6090 "Default lib path %s\n"
6091 "Hints lib path %s\n"
6093 "Default hint file %s\n"
6097 __FreeBSD_version, ld_standard_library_path,
6099 ld_env_prefix, ld_elf_hints_default,
6101 ld_path_libmap_conf);
6104 _rtld_error("Invalid argument: '%s'", arg);
6105 print_usage(argv[0]);
6117 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
6120 parse_integer(const char *str)
6122 static const int RADIX = 10; /* XXXJA: possibly support hex? */
6129 for (c = *str; c != '\0'; c = *++str) {
6130 if (c < '0' || c > '9')
6137 /* Make sure we actually parsed something. */
6144 print_usage(const char *argv0)
6148 "Usage: %s [-h] [-b <exe>] [-d] [-f <FD>] [-p] [--] <binary> [<args>]\n"
6151 " -h Display this help message\n"
6152 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
6153 " -d Ignore lack of exec permissions for the binary\n"
6154 " -f <FD> Execute <FD> instead of searching for <binary>\n"
6155 " -p Search in PATH for named binary\n"
6156 " -u Ignore LD_ environment variables\n"
6157 " -v Display identification information\n"
6158 " -- End of RTLD options\n"
6159 " <binary> Name of process to execute\n"
6160 " <args> Arguments to the executed process\n", argv0);
6163 #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt }
6164 static const struct auxfmt {
6168 AUXFMT(AT_NULL, NULL),
6169 AUXFMT(AT_IGNORE, NULL),
6170 AUXFMT(AT_EXECFD, "%ld"),
6171 AUXFMT(AT_PHDR, "%p"),
6172 AUXFMT(AT_PHENT, "%lu"),
6173 AUXFMT(AT_PHNUM, "%lu"),
6174 AUXFMT(AT_PAGESZ, "%lu"),
6175 AUXFMT(AT_BASE, "%#lx"),
6176 AUXFMT(AT_FLAGS, "%#lx"),
6177 AUXFMT(AT_ENTRY, "%p"),
6178 AUXFMT(AT_NOTELF, NULL),
6179 AUXFMT(AT_UID, "%ld"),
6180 AUXFMT(AT_EUID, "%ld"),
6181 AUXFMT(AT_GID, "%ld"),
6182 AUXFMT(AT_EGID, "%ld"),
6183 AUXFMT(AT_EXECPATH, "%s"),
6184 AUXFMT(AT_CANARY, "%p"),
6185 AUXFMT(AT_CANARYLEN, "%lu"),
6186 AUXFMT(AT_OSRELDATE, "%lu"),
6187 AUXFMT(AT_NCPUS, "%lu"),
6188 AUXFMT(AT_PAGESIZES, "%p"),
6189 AUXFMT(AT_PAGESIZESLEN, "%lu"),
6190 AUXFMT(AT_TIMEKEEP, "%p"),
6191 AUXFMT(AT_STACKPROT, "%#lx"),
6192 AUXFMT(AT_EHDRFLAGS, "%#lx"),
6193 AUXFMT(AT_HWCAP, "%#lx"),
6194 AUXFMT(AT_HWCAP2, "%#lx"),
6195 AUXFMT(AT_BSDFLAGS, "%#lx"),
6196 AUXFMT(AT_ARGC, "%lu"),
6197 AUXFMT(AT_ARGV, "%p"),
6198 AUXFMT(AT_ENVC, "%p"),
6199 AUXFMT(AT_ENVV, "%p"),
6200 AUXFMT(AT_PS_STRINGS, "%p"),
6201 AUXFMT(AT_FXRNG, "%p"),
6202 AUXFMT(AT_KPRELOAD, "%p"),
6203 AUXFMT(AT_USRSTACKBASE, "%#lx"),
6204 AUXFMT(AT_USRSTACKLIM, "%#lx"),
6208 is_ptr_fmt(const char *fmt)
6212 last = fmt[strlen(fmt) - 1];
6213 return (last == 'p' || last == 's');
6217 dump_auxv(Elf_Auxinfo **aux_info)
6220 const struct auxfmt *fmt;
6223 for (i = 0; i < AT_COUNT; i++) {
6228 if (fmt->fmt == NULL)
6230 rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name);
6231 if (is_ptr_fmt(fmt->fmt)) {
6232 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6235 rtld_fdprintfx(STDOUT_FILENO, fmt->fmt,
6238 rtld_fdprintf(STDOUT_FILENO, "\n");
6243 * Overrides for libc_pic-provided functions.
6247 __getosreldate(void)
6257 oid[1] = KERN_OSRELDATE;
6259 len = sizeof(osrel);
6260 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
6261 if (error == 0 && osrel > 0 && len == sizeof(osrel))
6266 rtld_strerror(int errnum)
6269 if (errnum < 0 || errnum >= sys_nerr)
6270 return ("Unknown error");
6271 return (sys_errlist[errnum]);
6275 getenv(const char *name)
6277 return (__DECONST(char *, rtld_get_env_val(environ, name,
6283 malloc(size_t nbytes)
6286 return (__crt_malloc(nbytes));
6290 calloc(size_t num, size_t size)
6293 return (__crt_calloc(num, size));
6304 realloc(void *cp, size_t nbytes)
6307 return (__crt_realloc(cp, nbytes));
6310 extern int _rtld_version__FreeBSD_version __exported;
6311 int _rtld_version__FreeBSD_version = __FreeBSD_version;
6313 extern char _rtld_version_laddr_offset __exported;
6314 char _rtld_version_laddr_offset;
6316 extern char _rtld_version_dlpi_tls_data __exported;
6317 char _rtld_version_dlpi_tls_data;