2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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>
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 errmsg_restore(struct dlerror_save *);
108 static struct dlerror_save *errmsg_save(void);
109 static void *fill_search_info(const char *, size_t, void *);
110 static char *find_library(const char *, const Obj_Entry *, int *);
111 static const char *gethints(bool);
112 static void hold_object(Obj_Entry *);
113 static void unhold_object(Obj_Entry *);
114 static void init_dag(Obj_Entry *);
115 static void init_marker(Obj_Entry *);
116 static void init_pagesizes(Elf_Auxinfo **aux_info);
117 static void init_rtld(caddr_t, Elf_Auxinfo **);
118 static void initlist_add_neededs(Needed_Entry *, Objlist *);
119 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
120 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
121 static void linkmap_add(Obj_Entry *);
122 static void linkmap_delete(Obj_Entry *);
123 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
124 static void unload_filtees(Obj_Entry *, RtldLockState *);
125 static int load_needed_objects(Obj_Entry *, int);
126 static int load_preload_objects(char *, bool);
127 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
128 static void map_stacks_exec(RtldLockState *);
129 static int obj_disable_relro(Obj_Entry *);
130 static int obj_enforce_relro(Obj_Entry *);
131 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
132 static void objlist_call_init(Objlist *, RtldLockState *);
133 static void objlist_clear(Objlist *);
134 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
135 static void objlist_init(Objlist *);
136 static void objlist_push_head(Objlist *, Obj_Entry *);
137 static void objlist_push_tail(Objlist *, Obj_Entry *);
138 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
139 static void objlist_remove(Objlist *, Obj_Entry *);
140 static int open_binary_fd(const char *argv0, bool search_in_path,
141 const char **binpath_res);
142 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
144 static int parse_integer(const char *);
145 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
146 static void print_usage(const char *argv0);
147 static void release_object(Obj_Entry *);
148 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
149 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
150 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
151 int flags, RtldLockState *lockstate);
152 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
154 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
155 static int rtld_dirname(const char *, char *);
156 static int rtld_dirname_abs(const char *, char *);
157 static void *rtld_dlopen(const char *name, int fd, int mode);
158 static void rtld_exit(void);
159 static void rtld_nop_exit(void);
160 static char *search_library_path(const char *, const char *, const char *,
162 static char *search_library_pathfds(const char *, const char *, int *);
163 static const void **get_program_var_addr(const char *, RtldLockState *);
164 static void set_program_var(const char *, const void *);
165 static int symlook_default(SymLook *, const Obj_Entry *refobj);
166 static int symlook_global(SymLook *, DoneList *);
167 static void symlook_init_from_req(SymLook *, const SymLook *);
168 static int symlook_list(SymLook *, const Objlist *, DoneList *);
169 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
170 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
171 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
172 static void *tls_get_addr_slow(Elf_Addr **, int, size_t, bool) __noinline;
173 static void trace_loaded_objects(Obj_Entry *);
174 static void unlink_object(Obj_Entry *);
175 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
176 static void unref_dag(Obj_Entry *);
177 static void ref_dag(Obj_Entry *);
178 static char *origin_subst_one(Obj_Entry *, char *, const char *,
180 static char *origin_subst(Obj_Entry *, const char *);
181 static bool obj_resolve_origin(Obj_Entry *obj);
182 static void preinit_main(void);
183 static int rtld_verify_versions(const Objlist *);
184 static int rtld_verify_object_versions(Obj_Entry *);
185 static void object_add_name(Obj_Entry *, const char *);
186 static int object_match_name(const Obj_Entry *, const char *);
187 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
188 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
189 struct dl_phdr_info *phdr_info);
190 static uint32_t gnu_hash(const char *);
191 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
192 const unsigned long);
194 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
195 void _r_debug_postinit(struct link_map *) __noinline __exported;
197 int __sys_openat(int, const char *, int, ...);
202 struct r_debug r_debug __exported; /* for GDB; */
203 static bool libmap_disable; /* Disable libmap */
204 static bool ld_loadfltr; /* Immediate filters processing */
205 static char *libmap_override; /* Maps to use in addition to libmap.conf */
206 static bool trust; /* False for setuid and setgid programs */
207 static bool dangerous_ld_env; /* True if environment variables have been
208 used to affect the libraries loaded */
209 bool ld_bind_not; /* Disable PLT update */
210 static char *ld_bind_now; /* Environment variable for immediate binding */
211 static char *ld_debug; /* Environment variable for debugging */
212 static char *ld_library_path; /* Environment variable for search path */
213 static char *ld_library_dirs; /* Environment variable for library descriptors */
214 static char *ld_preload; /* Environment variable for libraries to
216 static char *ld_preload_fds; /* Environment variable for libraries represented by
218 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
219 static const char *ld_tracing; /* Called from ldd to print libs */
220 static char *ld_utrace; /* Use utrace() to log events. */
221 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
222 static Obj_Entry *obj_main; /* The main program shared object */
223 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
224 static unsigned int obj_count; /* Number of objects in obj_list */
225 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
227 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
228 STAILQ_HEAD_INITIALIZER(list_global);
229 static Objlist list_main = /* Objects loaded at program startup */
230 STAILQ_HEAD_INITIALIZER(list_main);
231 static Objlist list_fini = /* Objects needing fini() calls */
232 STAILQ_HEAD_INITIALIZER(list_fini);
234 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
236 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
238 extern Elf_Dyn _DYNAMIC;
239 #pragma weak _DYNAMIC
241 int dlclose(void *) __exported;
242 char *dlerror(void) __exported;
243 void *dlopen(const char *, int) __exported;
244 void *fdlopen(int, int) __exported;
245 void *dlsym(void *, const char *) __exported;
246 dlfunc_t dlfunc(void *, const char *) __exported;
247 void *dlvsym(void *, const char *, const char *) __exported;
248 int dladdr(const void *, Dl_info *) __exported;
249 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
250 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
251 int dlinfo(void *, int , void *) __exported;
252 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
253 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
254 int _rtld_get_stack_prot(void) __exported;
255 int _rtld_is_dlopened(void *) __exported;
256 void _rtld_error(const char *, ...) __exported;
258 /* Only here to fix -Wmissing-prototypes warnings */
259 int __getosreldate(void);
260 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
261 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
265 static int osreldate;
268 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
269 static int max_stack_flags;
272 * Global declarations normally provided by crt1. The dynamic linker is
273 * not built with crt1, so we have to provide them ourselves.
279 * Used to pass argc, argv to init functions.
285 * Globals to control TLS allocation.
287 size_t tls_last_offset; /* Static TLS offset of last module */
288 size_t tls_last_size; /* Static TLS size of last module */
289 size_t tls_static_space; /* Static TLS space allocated */
290 static size_t tls_static_max_align;
291 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
292 int tls_max_index = 1; /* Largest module index allocated */
294 static bool ld_library_path_rpath = false;
295 bool ld_fast_sigblock = false;
298 * Globals for path names, and such
300 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
301 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
302 const char *ld_path_rtld = _PATH_RTLD;
303 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
304 const char *ld_env_prefix = LD_;
306 static void (*rtld_exit_ptr)(void);
309 * Fill in a DoneList with an allocation large enough to hold all of
310 * the currently-loaded objects. Keep this as a macro since it calls
311 * alloca and we want that to occur within the scope of the caller.
313 #define donelist_init(dlp) \
314 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
315 assert((dlp)->objs != NULL), \
316 (dlp)->num_alloc = obj_count, \
319 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
320 if (ld_utrace != NULL) \
321 ld_utrace_log(e, h, mb, ms, r, n); \
325 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
326 int refcnt, const char *name)
328 struct utrace_rtld ut;
329 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
331 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
334 ut.mapbase = mapbase;
335 ut.mapsize = mapsize;
337 bzero(ut.name, sizeof(ut.name));
339 strlcpy(ut.name, name, sizeof(ut.name));
340 utrace(&ut, sizeof(ut));
343 #ifdef RTLD_VARIANT_ENV_NAMES
345 * construct the env variable based on the type of binary that's
348 static inline const char *
351 static char buffer[128];
353 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
354 strlcat(buffer, var, sizeof(buffer));
362 * Main entry point for dynamic linking. The first argument is the
363 * stack pointer. The stack is expected to be laid out as described
364 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
365 * Specifically, the stack pointer points to a word containing
366 * ARGC. Following that in the stack is a null-terminated sequence
367 * of pointers to argument strings. Then comes a null-terminated
368 * sequence of pointers to environment strings. Finally, there is a
369 * sequence of "auxiliary vector" entries.
371 * The second argument points to a place to store the dynamic linker's
372 * exit procedure pointer and the third to a place to store the main
375 * The return value is the main program's entry point.
378 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
380 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
381 Objlist_Entry *entry;
382 Obj_Entry *last_interposer, *obj, *preload_tail;
383 const Elf_Phdr *phdr;
385 RtldLockState lockstate;
388 char **argv, **env, **envp, *kexecpath, *library_path_rpath;
389 const char *argv0, *binpath;
391 char buf[MAXPATHLEN];
392 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc;
395 int old_auxv_format = 1;
397 bool dir_enable, direct_exec, explicit_fd, search_in_path;
400 * On entry, the dynamic linker itself has not been relocated yet.
401 * Be very careful not to reference any global data until after
402 * init_rtld has returned. It is OK to reference file-scope statics
403 * and string constants, and to call static and global functions.
406 /* Find the auxiliary vector on the stack. */
410 sp += argc + 1; /* Skip over arguments and NULL terminator */
412 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
414 aux = (Elf_Auxinfo *) sp;
416 /* Digest the auxiliary vector. */
417 for (i = 0; i < AT_COUNT; i++)
419 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
420 if (auxp->a_type < AT_COUNT)
421 aux_info[auxp->a_type] = auxp;
423 if (auxp->a_type == 23) /* AT_STACKPROT */
429 if (old_auxv_format) {
430 /* Remap from old-style auxv numbers. */
431 aux_info[23] = aux_info[21]; /* AT_STACKPROT */
432 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */
433 aux_info[19] = aux_info[17]; /* AT_NCPUS */
434 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */
435 aux_info[15] = aux_info[13]; /* AT_EXECPATH */
436 aux_info[13] = NULL; /* AT_GID */
438 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */
439 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */
440 aux_info[16] = aux_info[14]; /* AT_CANARY */
441 aux_info[14] = NULL; /* AT_EGID */
445 /* Initialize and relocate ourselves. */
446 assert(aux_info[AT_BASE] != NULL);
447 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
451 __progname = obj_rtld.path;
452 argv0 = argv[0] != NULL ? argv[0] : "(null)";
457 if (aux_info[AT_BSDFLAGS] != NULL &&
458 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0)
459 ld_fast_sigblock = true;
461 trust = !issetugid();
464 md_abi_variant_hook(aux_info);
467 if (aux_info[AT_EXECFD] != NULL) {
468 fd = aux_info[AT_EXECFD]->a_un.a_val;
470 assert(aux_info[AT_PHDR] != NULL);
471 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
472 if (phdr == obj_rtld.phdr) {
474 _rtld_error("Tainted process refusing to run binary %s",
480 dbg("opening main program in direct exec mode");
482 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0);
483 explicit_fd = (fd != -1);
486 fd = open_binary_fd(argv0, search_in_path, &binpath);
487 if (fstat(fd, &st) == -1) {
488 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
489 explicit_fd ? "user-provided descriptor" : argv0,
490 rtld_strerror(errno));
495 * Rough emulation of the permission checks done by
496 * execve(2), only Unix DACs are checked, ACLs are
497 * ignored. Preserve the semantic of disabling owner
498 * to execute if owner x bit is cleared, even if
499 * others x bit is enabled.
500 * mmap(2) does not allow to mmap with PROT_EXEC if
501 * binary' file comes from noexec mount. We cannot
502 * set a text reference on the binary.
505 if (st.st_uid == geteuid()) {
506 if ((st.st_mode & S_IXUSR) != 0)
508 } else if (st.st_gid == getegid()) {
509 if ((st.st_mode & S_IXGRP) != 0)
511 } else if ((st.st_mode & S_IXOTH) != 0) {
515 _rtld_error("No execute permission for binary %s",
521 * For direct exec mode, argv[0] is the interpreter
522 * name, we must remove it and shift arguments left
523 * before invoking binary main. Since stack layout
524 * places environment pointers and aux vectors right
525 * after the terminating NULL, we must shift
526 * environment and aux as well.
528 main_argc = argc - rtld_argc;
529 for (i = 0; i <= main_argc; i++)
530 argv[i] = argv[i + rtld_argc];
532 environ = env = envp = argv + main_argc + 1;
533 dbg("move env from %p to %p", envp + rtld_argc, envp);
535 *envp = *(envp + rtld_argc);
536 } while (*envp++ != NULL);
537 aux = auxp = (Elf_Auxinfo *)envp;
538 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
539 dbg("move aux from %p to %p", auxpf, aux);
540 /* XXXKIB insert place for AT_EXECPATH if not present */
541 for (;; auxp++, auxpf++) {
543 if (auxp->a_type == AT_NULL)
546 /* Since the auxiliary vector has moved, redigest it. */
547 for (i = 0; i < AT_COUNT; i++)
549 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
550 if (auxp->a_type < AT_COUNT)
551 aux_info[auxp->a_type] = auxp;
554 /* Point AT_EXECPATH auxv and aux_info to the binary path. */
555 if (binpath == NULL) {
556 aux_info[AT_EXECPATH] = NULL;
558 if (aux_info[AT_EXECPATH] == NULL) {
559 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo));
560 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH;
562 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *,
566 _rtld_error("No binary");
572 ld_bind_now = getenv(_LD("BIND_NOW"));
575 * If the process is tainted, then we un-set the dangerous environment
576 * variables. The process will be marked as tainted until setuid(2)
577 * is called. If any child process calls setuid(2) we do not want any
578 * future processes to honor the potentially un-safe variables.
581 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
582 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
583 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
584 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
585 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH")) ||
586 unsetenv(_LD("PRELOAD_FDS"))) {
587 _rtld_error("environment corrupt; aborting");
591 ld_debug = getenv(_LD("DEBUG"));
592 if (ld_bind_now == NULL)
593 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
594 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
595 libmap_override = getenv(_LD("LIBMAP"));
596 ld_library_path = getenv(_LD("LIBRARY_PATH"));
597 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
598 ld_preload = getenv(_LD("PRELOAD"));
599 ld_preload_fds = getenv(_LD("PRELOAD_FDS"));
600 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
601 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
602 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
603 if (library_path_rpath != NULL) {
604 if (library_path_rpath[0] == 'y' ||
605 library_path_rpath[0] == 'Y' ||
606 library_path_rpath[0] == '1')
607 ld_library_path_rpath = true;
609 ld_library_path_rpath = false;
611 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
612 (ld_library_path != NULL) || (ld_preload != NULL) ||
613 (ld_elf_hints_path != NULL) || ld_loadfltr;
614 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
615 ld_utrace = getenv(_LD("UTRACE"));
617 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
618 ld_elf_hints_path = ld_elf_hints_default;
620 if (ld_debug != NULL && *ld_debug != '\0')
622 dbg("%s is initialized, base address = %p", __progname,
623 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
624 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
625 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
627 dbg("initializing thread locks");
631 * Load the main program, or process its program header if it is
634 if (fd != -1) { /* Load the main program. */
635 dbg("loading main program");
636 obj_main = map_object(fd, argv0, NULL);
638 if (obj_main == NULL)
640 max_stack_flags = obj_main->stack_flags;
641 } else { /* Main program already loaded. */
642 dbg("processing main program's program header");
643 assert(aux_info[AT_PHDR] != NULL);
644 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
645 assert(aux_info[AT_PHNUM] != NULL);
646 phnum = aux_info[AT_PHNUM]->a_un.a_val;
647 assert(aux_info[AT_PHENT] != NULL);
648 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
649 assert(aux_info[AT_ENTRY] != NULL);
650 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
651 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
655 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
656 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
657 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
658 if (kexecpath[0] == '/')
659 obj_main->path = kexecpath;
660 else if (getcwd(buf, sizeof(buf)) == NULL ||
661 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
662 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
663 obj_main->path = xstrdup(argv0);
665 obj_main->path = xstrdup(buf);
667 dbg("No AT_EXECPATH or direct exec");
668 obj_main->path = xstrdup(argv0);
670 dbg("obj_main path %s", obj_main->path);
671 obj_main->mainprog = true;
673 if (aux_info[AT_STACKPROT] != NULL &&
674 aux_info[AT_STACKPROT]->a_un.a_val != 0)
675 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
679 * Get the actual dynamic linker pathname from the executable if
680 * possible. (It should always be possible.) That ensures that
681 * gdb will find the right dynamic linker even if a non-standard
684 if (obj_main->interp != NULL &&
685 strcmp(obj_main->interp, obj_rtld.path) != 0) {
687 obj_rtld.path = xstrdup(obj_main->interp);
688 __progname = obj_rtld.path;
692 if (!digest_dynamic(obj_main, 0))
694 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
695 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
696 obj_main->dynsymcount);
698 linkmap_add(obj_main);
699 linkmap_add(&obj_rtld);
701 /* Link the main program into the list of objects. */
702 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
706 /* Initialize a fake symbol for resolving undefined weak references. */
707 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
708 sym_zero.st_shndx = SHN_UNDEF;
709 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
712 libmap_disable = (bool)lm_init(libmap_override);
714 dbg("loading LD_PRELOAD_FDS libraries");
715 if (load_preload_objects(ld_preload_fds, true) == -1)
718 dbg("loading LD_PRELOAD libraries");
719 if (load_preload_objects(ld_preload, false) == -1)
721 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
723 dbg("loading needed objects");
724 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE :
728 /* Make a list of all objects loaded at startup. */
729 last_interposer = obj_main;
730 TAILQ_FOREACH(obj, &obj_list, next) {
733 if (obj->z_interpose && obj != obj_main) {
734 objlist_put_after(&list_main, last_interposer, obj);
735 last_interposer = obj;
737 objlist_push_tail(&list_main, obj);
742 dbg("checking for required versions");
743 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
746 if (ld_tracing) { /* We're done */
747 trace_loaded_objects(obj_main);
751 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
752 dump_relocations(obj_main);
757 * Processing tls relocations requires having the tls offsets
758 * initialized. Prepare offsets before starting initial
759 * relocation processing.
761 dbg("initializing initial thread local storage offsets");
762 STAILQ_FOREACH(entry, &list_main, link) {
764 * Allocate all the initial objects out of the static TLS
765 * block even if they didn't ask for it.
767 allocate_tls_offset(entry->obj);
770 if (relocate_objects(obj_main,
771 ld_bind_now != NULL && *ld_bind_now != '\0',
772 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
775 dbg("doing copy relocations");
776 if (do_copy_relocations(obj_main) == -1)
779 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
780 dump_relocations(obj_main);
787 * Setup TLS for main thread. This must be done after the
788 * relocations are processed, since tls initialization section
789 * might be the subject for relocations.
791 dbg("initializing initial thread local storage");
792 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
794 dbg("initializing key program variables");
795 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
796 set_program_var("environ", env);
797 set_program_var("__elf_aux_vector", aux);
799 /* Make a list of init functions to call. */
800 objlist_init(&initlist);
801 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
802 preload_tail, &initlist);
804 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
806 map_stacks_exec(NULL);
808 if (!obj_main->crt_no_init) {
810 * Make sure we don't call the main program's init and fini
811 * functions for binaries linked with old crt1 which calls
814 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
815 obj_main->preinit_array = obj_main->init_array =
816 obj_main->fini_array = (Elf_Addr)NULL;
820 /* Set osrel for direct-execed binary */
823 mib[2] = KERN_PROC_OSREL;
825 osrel = obj_main->osrel;
826 sz = sizeof(old_osrel);
827 dbg("setting osrel to %d", osrel);
828 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
831 wlock_acquire(rtld_bind_lock, &lockstate);
833 dbg("resolving ifuncs");
834 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
835 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
838 rtld_exit_ptr = rtld_exit;
839 if (obj_main->crt_no_init)
841 objlist_call_init(&initlist, &lockstate);
842 _r_debug_postinit(&obj_main->linkmap);
843 objlist_clear(&initlist);
844 dbg("loading filtees");
845 TAILQ_FOREACH(obj, &obj_list, next) {
848 if (ld_loadfltr || obj->z_loadfltr)
849 load_filtees(obj, 0, &lockstate);
852 dbg("enforcing main obj relro");
853 if (obj_enforce_relro(obj_main) == -1)
856 lock_release(rtld_bind_lock, &lockstate);
858 dbg("transferring control to program entry point = %p", obj_main->entry);
860 /* Return the exit procedure and the program entry point. */
861 *exit_proc = rtld_exit_ptr;
863 return (func_ptr_type) obj_main->entry;
867 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
872 ptr = (void *)make_function_pointer(def, obj);
873 target = call_ifunc_resolver(ptr);
874 return ((void *)target);
878 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
879 * Changes to this function should be applied there as well.
882 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
886 const Obj_Entry *defobj;
889 RtldLockState lockstate;
891 rlock_acquire(rtld_bind_lock, &lockstate);
892 if (sigsetjmp(lockstate.env, 0) != 0)
893 lock_upgrade(rtld_bind_lock, &lockstate);
895 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
897 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
899 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
900 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
904 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
905 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
907 target = (Elf_Addr)(defobj->relocbase + def->st_value);
909 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
910 defobj->strtab + def->st_name,
911 obj->path == NULL ? NULL : basename(obj->path),
913 defobj->path == NULL ? NULL : basename(defobj->path));
916 * Write the new contents for the jmpslot. Note that depending on
917 * architecture, the value which we need to return back to the
918 * lazy binding trampoline may or may not be the target
919 * address. The value returned from reloc_jmpslot() is the value
920 * that the trampoline needs.
922 target = reloc_jmpslot(where, target, defobj, obj, rel);
923 lock_release(rtld_bind_lock, &lockstate);
928 * Error reporting function. Use it like printf. If formats the message
929 * into a buffer, and sets things up so that the next call to dlerror()
930 * will return the message.
933 _rtld_error(const char *fmt, ...)
938 rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz,
941 *lockinfo.dlerror_seen() = 0;
942 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc());
946 * Return a dynamically-allocated copy of the current error message, if any.
948 static struct dlerror_save *
951 struct dlerror_save *res;
953 res = xmalloc(sizeof(*res));
954 res->seen = *lockinfo.dlerror_seen();
956 res->msg = xstrdup(lockinfo.dlerror_loc());
961 * Restore the current error message from a copy which was previously saved
962 * by errmsg_save(). The copy is freed.
965 errmsg_restore(struct dlerror_save *saved_msg)
967 if (saved_msg == NULL || saved_msg->seen == 1) {
968 *lockinfo.dlerror_seen() = 1;
970 *lockinfo.dlerror_seen() = 0;
971 strlcpy(lockinfo.dlerror_loc(), saved_msg->msg,
972 lockinfo.dlerror_loc_sz);
973 free(saved_msg->msg);
979 basename(const char *name)
981 const char *p = strrchr(name, '/');
982 return p != NULL ? p + 1 : name;
985 static struct utsname uts;
988 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
989 const char *subst, bool may_free)
991 char *p, *p1, *res, *resp;
992 int subst_len, kw_len, subst_count, old_len, new_len;
997 * First, count the number of the keyword occurrences, to
998 * preallocate the final string.
1000 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
1007 * If the keyword is not found, just return.
1009 * Return non-substituted string if resolution failed. We
1010 * cannot do anything more reasonable, the failure mode of the
1011 * caller is unresolved library anyway.
1013 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
1014 return (may_free ? real : xstrdup(real));
1016 subst = obj->origin_path;
1019 * There is indeed something to substitute. Calculate the
1020 * length of the resulting string, and allocate it.
1022 subst_len = strlen(subst);
1023 old_len = strlen(real);
1024 new_len = old_len + (subst_len - kw_len) * subst_count;
1025 res = xmalloc(new_len + 1);
1028 * Now, execute the substitution loop.
1030 for (p = real, resp = res, *resp = '\0';;) {
1033 /* Copy the prefix before keyword. */
1034 memcpy(resp, p, p1 - p);
1036 /* Keyword replacement. */
1037 memcpy(resp, subst, subst_len);
1045 /* Copy to the end of string and finish. */
1053 origin_subst(Obj_Entry *obj, const char *real)
1055 char *res1, *res2, *res3, *res4;
1057 if (obj == NULL || !trust)
1058 return (xstrdup(real));
1059 if (uts.sysname[0] == '\0') {
1060 if (uname(&uts) != 0) {
1061 _rtld_error("utsname failed: %d", errno);
1065 /* __DECONST is safe here since without may_free real is unchanged */
1066 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL,
1068 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
1069 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
1070 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
1077 const char *msg = dlerror();
1080 msg = "Fatal error";
1081 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1082 rtld_fdputstr(STDERR_FILENO, msg);
1083 rtld_fdputchar(STDERR_FILENO, '\n');
1088 * Process a shared object's DYNAMIC section, and save the important
1089 * information in its Obj_Entry structure.
1092 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1093 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1095 const Elf_Dyn *dynp;
1096 Needed_Entry **needed_tail = &obj->needed;
1097 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1098 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1099 const Elf_Hashelt *hashtab;
1100 const Elf32_Word *hashval;
1101 Elf32_Word bkt, nmaskwords;
1103 int plttype = DT_REL;
1107 *dyn_runpath = NULL;
1109 obj->bind_now = false;
1110 dynp = obj->dynamic;
1113 for (; dynp->d_tag != DT_NULL; dynp++) {
1114 switch (dynp->d_tag) {
1117 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1121 obj->relsize = dynp->d_un.d_val;
1125 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1129 obj->pltrel = (const Elf_Rel *)
1130 (obj->relocbase + dynp->d_un.d_ptr);
1134 obj->pltrelsize = dynp->d_un.d_val;
1138 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1142 obj->relasize = dynp->d_un.d_val;
1146 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1150 plttype = dynp->d_un.d_val;
1151 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1155 obj->symtab = (const Elf_Sym *)
1156 (obj->relocbase + dynp->d_un.d_ptr);
1160 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1164 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1168 obj->strsize = dynp->d_un.d_val;
1172 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1177 obj->verneednum = dynp->d_un.d_val;
1181 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1186 obj->verdefnum = dynp->d_un.d_val;
1190 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1196 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1198 obj->nbuckets = hashtab[0];
1199 obj->nchains = hashtab[1];
1200 obj->buckets = hashtab + 2;
1201 obj->chains = obj->buckets + obj->nbuckets;
1202 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1203 obj->buckets != NULL;
1209 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1211 obj->nbuckets_gnu = hashtab[0];
1212 obj->symndx_gnu = hashtab[1];
1213 nmaskwords = hashtab[2];
1214 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1215 obj->maskwords_bm_gnu = nmaskwords - 1;
1216 obj->shift2_gnu = hashtab[3];
1217 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1218 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1219 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1221 /* Number of bitmask words is required to be power of 2 */
1222 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1223 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1229 Needed_Entry *nep = NEW(Needed_Entry);
1230 nep->name = dynp->d_un.d_val;
1235 needed_tail = &nep->next;
1241 Needed_Entry *nep = NEW(Needed_Entry);
1242 nep->name = dynp->d_un.d_val;
1246 *needed_filtees_tail = nep;
1247 needed_filtees_tail = &nep->next;
1249 if (obj->linkmap.l_refname == NULL)
1250 obj->linkmap.l_refname = (char *)dynp->d_un.d_val;
1256 Needed_Entry *nep = NEW(Needed_Entry);
1257 nep->name = dynp->d_un.d_val;
1261 *needed_aux_filtees_tail = nep;
1262 needed_aux_filtees_tail = &nep->next;
1267 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1271 obj->textrel = true;
1275 obj->symbolic = true;
1280 * We have to wait until later to process this, because we
1281 * might not have gotten the address of the string table yet.
1291 *dyn_runpath = dynp;
1295 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1298 case DT_PREINIT_ARRAY:
1299 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1302 case DT_PREINIT_ARRAYSZ:
1303 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1307 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1310 case DT_INIT_ARRAYSZ:
1311 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1315 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1319 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1322 case DT_FINI_ARRAYSZ:
1323 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1327 * Don't process DT_DEBUG on MIPS as the dynamic section
1328 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1334 dbg("Filling in DT_DEBUG entry");
1335 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1340 if (dynp->d_un.d_val & DF_ORIGIN)
1341 obj->z_origin = true;
1342 if (dynp->d_un.d_val & DF_SYMBOLIC)
1343 obj->symbolic = true;
1344 if (dynp->d_un.d_val & DF_TEXTREL)
1345 obj->textrel = true;
1346 if (dynp->d_un.d_val & DF_BIND_NOW)
1347 obj->bind_now = true;
1348 if (dynp->d_un.d_val & DF_STATIC_TLS)
1349 obj->static_tls = true;
1352 case DT_MIPS_LOCAL_GOTNO:
1353 obj->local_gotno = dynp->d_un.d_val;
1356 case DT_MIPS_SYMTABNO:
1357 obj->symtabno = dynp->d_un.d_val;
1360 case DT_MIPS_GOTSYM:
1361 obj->gotsym = dynp->d_un.d_val;
1364 case DT_MIPS_RLD_MAP:
1365 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1368 case DT_MIPS_RLD_MAP_REL:
1369 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map
1370 // section relative to the address of the tag itself.
1371 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) =
1372 (Elf_Addr) &r_debug;
1375 case DT_MIPS_PLTGOT:
1376 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase +
1383 #ifdef __powerpc64__
1384 case DT_PPC64_GLINK:
1385 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1389 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1395 if (dynp->d_un.d_val & DF_1_NOOPEN)
1396 obj->z_noopen = true;
1397 if (dynp->d_un.d_val & DF_1_ORIGIN)
1398 obj->z_origin = true;
1399 if (dynp->d_un.d_val & DF_1_GLOBAL)
1400 obj->z_global = true;
1401 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1402 obj->bind_now = true;
1403 if (dynp->d_un.d_val & DF_1_NODELETE)
1404 obj->z_nodelete = true;
1405 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1406 obj->z_loadfltr = true;
1407 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1408 obj->z_interpose = true;
1409 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1410 obj->z_nodeflib = true;
1411 if (dynp->d_un.d_val & DF_1_PIE)
1417 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1424 obj->traced = false;
1426 if (plttype == DT_RELA) {
1427 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1429 obj->pltrelasize = obj->pltrelsize;
1430 obj->pltrelsize = 0;
1433 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1434 if (obj->valid_hash_sysv)
1435 obj->dynsymcount = obj->nchains;
1436 else if (obj->valid_hash_gnu) {
1437 obj->dynsymcount = 0;
1438 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1439 if (obj->buckets_gnu[bkt] == 0)
1441 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1444 while ((*hashval++ & 1u) == 0);
1446 obj->dynsymcount += obj->symndx_gnu;
1449 if (obj->linkmap.l_refname != NULL)
1450 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj->
1455 obj_resolve_origin(Obj_Entry *obj)
1458 if (obj->origin_path != NULL)
1460 obj->origin_path = xmalloc(PATH_MAX);
1461 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1465 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1466 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1469 if (obj->z_origin && !obj_resolve_origin(obj))
1472 if (dyn_runpath != NULL) {
1473 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1474 obj->runpath = origin_subst(obj, obj->runpath);
1475 } else if (dyn_rpath != NULL) {
1476 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1477 obj->rpath = origin_subst(obj, obj->rpath);
1479 if (dyn_soname != NULL)
1480 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1485 digest_dynamic(Obj_Entry *obj, int early)
1487 const Elf_Dyn *dyn_rpath;
1488 const Elf_Dyn *dyn_soname;
1489 const Elf_Dyn *dyn_runpath;
1491 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1492 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1496 * Process a shared object's program header. This is used only for the
1497 * main program, when the kernel has already loaded the main program
1498 * into memory before calling the dynamic linker. It creates and
1499 * returns an Obj_Entry structure.
1502 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1505 const Elf_Phdr *phlimit = phdr + phnum;
1507 Elf_Addr note_start, note_end;
1511 for (ph = phdr; ph < phlimit; ph++) {
1512 if (ph->p_type != PT_PHDR)
1516 obj->phsize = ph->p_memsz;
1517 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1521 obj->stack_flags = PF_X | PF_R | PF_W;
1523 for (ph = phdr; ph < phlimit; ph++) {
1524 switch (ph->p_type) {
1527 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1531 if (nsegs == 0) { /* First load segment */
1532 obj->vaddrbase = trunc_page(ph->p_vaddr);
1533 obj->mapbase = obj->vaddrbase + obj->relocbase;
1534 } else { /* Last load segment */
1535 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1542 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1547 obj->tlssize = ph->p_memsz;
1548 obj->tlsalign = ph->p_align;
1549 obj->tlsinitsize = ph->p_filesz;
1550 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1551 obj->tlspoffset = ph->p_offset;
1555 obj->stack_flags = ph->p_flags;
1559 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1560 obj->relro_size = round_page(ph->p_memsz);
1564 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1565 note_end = note_start + ph->p_filesz;
1566 digest_notes(obj, note_start, note_end);
1571 _rtld_error("%s: too few PT_LOAD segments", path);
1580 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1582 const Elf_Note *note;
1583 const char *note_name;
1586 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1587 note = (const Elf_Note *)((const char *)(note + 1) +
1588 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1589 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1590 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1591 note->n_descsz != sizeof(int32_t))
1593 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1594 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1595 note->n_type != NT_FREEBSD_NOINIT_TAG)
1597 note_name = (const char *)(note + 1);
1598 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1599 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1601 switch (note->n_type) {
1602 case NT_FREEBSD_ABI_TAG:
1603 /* FreeBSD osrel note */
1604 p = (uintptr_t)(note + 1);
1605 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1606 obj->osrel = *(const int32_t *)(p);
1607 dbg("note osrel %d", obj->osrel);
1609 case NT_FREEBSD_FEATURE_CTL:
1610 /* FreeBSD ABI feature control note */
1611 p = (uintptr_t)(note + 1);
1612 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1613 obj->fctl0 = *(const uint32_t *)(p);
1614 dbg("note fctl0 %#x", obj->fctl0);
1616 case NT_FREEBSD_NOINIT_TAG:
1617 /* FreeBSD 'crt does not call init' note */
1618 obj->crt_no_init = true;
1619 dbg("note crt_no_init");
1626 dlcheck(void *handle)
1630 TAILQ_FOREACH(obj, &obj_list, next) {
1631 if (obj == (Obj_Entry *) handle)
1635 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1636 _rtld_error("Invalid shared object handle %p", handle);
1643 * If the given object is already in the donelist, return true. Otherwise
1644 * add the object to the list and return false.
1647 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1651 for (i = 0; i < dlp->num_used; i++)
1652 if (dlp->objs[i] == obj)
1655 * Our donelist allocation should always be sufficient. But if
1656 * our threads locking isn't working properly, more shared objects
1657 * could have been loaded since we allocated the list. That should
1658 * never happen, but we'll handle it properly just in case it does.
1660 if (dlp->num_used < dlp->num_alloc)
1661 dlp->objs[dlp->num_used++] = obj;
1666 * Hash function for symbol table lookup. Don't even think about changing
1667 * this. It is specified by the System V ABI.
1670 elf_hash(const char *name)
1672 const unsigned char *p = (const unsigned char *) name;
1673 unsigned long h = 0;
1676 while (*p != '\0') {
1677 h = (h << 4) + *p++;
1678 if ((g = h & 0xf0000000) != 0)
1686 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1687 * unsigned in case it's implemented with a wider type.
1690 gnu_hash(const char *s)
1696 for (c = *s; c != '\0'; c = *++s)
1698 return (h & 0xffffffff);
1703 * Find the library with the given name, and return its full pathname.
1704 * The returned string is dynamically allocated. Generates an error
1705 * message and returns NULL if the library cannot be found.
1707 * If the second argument is non-NULL, then it refers to an already-
1708 * loaded shared object, whose library search path will be searched.
1710 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1711 * descriptor (which is close-on-exec) will be passed out via the third
1714 * The search order is:
1715 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1716 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1718 * DT_RUNPATH in the referencing file
1719 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1721 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1723 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1726 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1728 char *pathname, *refobj_path;
1730 bool nodeflib, objgiven;
1732 objgiven = refobj != NULL;
1734 if (libmap_disable || !objgiven ||
1735 (name = lm_find(refobj->path, xname)) == NULL)
1738 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1739 if (name[0] != '/' && !trust) {
1740 _rtld_error("Absolute pathname required "
1741 "for shared object \"%s\"", name);
1744 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1745 __DECONST(char *, name)));
1748 dbg(" Searching for \"%s\"", name);
1749 refobj_path = objgiven ? refobj->path : NULL;
1752 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1753 * back to pre-conforming behaviour if user requested so with
1754 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1757 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1758 pathname = search_library_path(name, ld_library_path,
1760 if (pathname != NULL)
1762 if (refobj != NULL) {
1763 pathname = search_library_path(name, refobj->rpath,
1765 if (pathname != NULL)
1768 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1769 if (pathname != NULL)
1771 pathname = search_library_path(name, gethints(false),
1773 if (pathname != NULL)
1775 pathname = search_library_path(name, ld_standard_library_path,
1777 if (pathname != NULL)
1780 nodeflib = objgiven ? refobj->z_nodeflib : false;
1782 pathname = search_library_path(name, refobj->rpath,
1784 if (pathname != NULL)
1787 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1788 pathname = search_library_path(name, obj_main->rpath,
1790 if (pathname != NULL)
1793 pathname = search_library_path(name, ld_library_path,
1795 if (pathname != NULL)
1798 pathname = search_library_path(name, refobj->runpath,
1800 if (pathname != NULL)
1803 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1804 if (pathname != NULL)
1806 pathname = search_library_path(name, gethints(nodeflib),
1808 if (pathname != NULL)
1810 if (objgiven && !nodeflib) {
1811 pathname = search_library_path(name,
1812 ld_standard_library_path, refobj_path, fdp);
1813 if (pathname != NULL)
1818 if (objgiven && refobj->path != NULL) {
1819 _rtld_error("Shared object \"%s\" not found, "
1820 "required by \"%s\"", name, basename(refobj->path));
1822 _rtld_error("Shared object \"%s\" not found", name);
1828 * Given a symbol number in a referencing object, find the corresponding
1829 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1830 * no definition was found. Returns a pointer to the Obj_Entry of the
1831 * defining object via the reference parameter DEFOBJ_OUT.
1834 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1835 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1836 RtldLockState *lockstate)
1840 const Obj_Entry *defobj;
1841 const Ver_Entry *ve;
1847 * If we have already found this symbol, get the information from
1850 if (symnum >= refobj->dynsymcount)
1851 return NULL; /* Bad object */
1852 if (cache != NULL && cache[symnum].sym != NULL) {
1853 *defobj_out = cache[symnum].obj;
1854 return cache[symnum].sym;
1857 ref = refobj->symtab + symnum;
1858 name = refobj->strtab + ref->st_name;
1864 * We don't have to do a full scale lookup if the symbol is local.
1865 * We know it will bind to the instance in this load module; to
1866 * which we already have a pointer (ie ref). By not doing a lookup,
1867 * we not only improve performance, but it also avoids unresolvable
1868 * symbols when local symbols are not in the hash table. This has
1869 * been seen with the ia64 toolchain.
1871 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1872 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1873 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1876 symlook_init(&req, name);
1878 ve = req.ventry = fetch_ventry(refobj, symnum);
1879 req.lockstate = lockstate;
1880 res = symlook_default(&req, refobj);
1883 defobj = req.defobj_out;
1891 * If we found no definition and the reference is weak, treat the
1892 * symbol as having the value zero.
1894 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1900 *defobj_out = defobj;
1901 /* Record the information in the cache to avoid subsequent lookups. */
1902 if (cache != NULL) {
1903 cache[symnum].sym = def;
1904 cache[symnum].obj = defobj;
1907 if (refobj != &obj_rtld)
1908 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1909 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1915 * Return the search path from the ldconfig hints file, reading it if
1916 * necessary. If nostdlib is true, then the default search paths are
1917 * not added to result.
1919 * Returns NULL if there are problems with the hints file,
1920 * or if the search path there is empty.
1923 gethints(bool nostdlib)
1925 static char *filtered_path;
1926 static const char *hints;
1927 static struct elfhints_hdr hdr;
1928 struct fill_search_info_args sargs, hargs;
1929 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1930 struct dl_serpath *SLPpath, *hintpath;
1932 struct stat hint_stat;
1933 unsigned int SLPndx, hintndx, fndx, fcount;
1939 /* First call, read the hints file */
1940 if (hints == NULL) {
1941 /* Keep from trying again in case the hints file is bad. */
1944 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1948 * Check of hdr.dirlistlen value against type limit
1949 * intends to pacify static analyzers. Further
1950 * paranoia leads to checks that dirlist is fully
1951 * contained in the file range.
1953 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1954 hdr.magic != ELFHINTS_MAGIC ||
1955 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1956 fstat(fd, &hint_stat) == -1) {
1963 if (dl + hdr.dirlist < dl)
1966 if (dl + hdr.dirlistlen < dl)
1968 dl += hdr.dirlistlen;
1969 if (dl > hint_stat.st_size)
1971 p = xmalloc(hdr.dirlistlen + 1);
1972 if (pread(fd, p, hdr.dirlistlen + 1,
1973 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1974 p[hdr.dirlistlen] != '\0') {
1983 * If caller agreed to receive list which includes the default
1984 * paths, we are done. Otherwise, if we still did not
1985 * calculated filtered result, do it now.
1988 return (hints[0] != '\0' ? hints : NULL);
1989 if (filtered_path != NULL)
1993 * Obtain the list of all configured search paths, and the
1994 * list of the default paths.
1996 * First estimate the size of the results.
1998 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2000 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2003 sargs.request = RTLD_DI_SERINFOSIZE;
2004 sargs.serinfo = &smeta;
2005 hargs.request = RTLD_DI_SERINFOSIZE;
2006 hargs.serinfo = &hmeta;
2008 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2010 path_enumerate(hints, fill_search_info, NULL, &hargs);
2012 SLPinfo = xmalloc(smeta.dls_size);
2013 hintinfo = xmalloc(hmeta.dls_size);
2016 * Next fetch both sets of paths.
2018 sargs.request = RTLD_DI_SERINFO;
2019 sargs.serinfo = SLPinfo;
2020 sargs.serpath = &SLPinfo->dls_serpath[0];
2021 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
2023 hargs.request = RTLD_DI_SERINFO;
2024 hargs.serinfo = hintinfo;
2025 hargs.serpath = &hintinfo->dls_serpath[0];
2026 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
2028 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2030 path_enumerate(hints, fill_search_info, NULL, &hargs);
2033 * Now calculate the difference between two sets, by excluding
2034 * standard paths from the full set.
2038 filtered_path = xmalloc(hdr.dirlistlen + 1);
2039 hintpath = &hintinfo->dls_serpath[0];
2040 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
2042 SLPpath = &SLPinfo->dls_serpath[0];
2044 * Check each standard path against current.
2046 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
2047 /* matched, skip the path */
2048 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2056 * Not matched against any standard path, add the path
2057 * to result. Separate consequtive paths with ':'.
2060 filtered_path[fndx] = ':';
2064 flen = strlen(hintpath->dls_name);
2065 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2068 filtered_path[fndx] = '\0';
2074 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2078 init_dag(Obj_Entry *root)
2080 const Needed_Entry *needed;
2081 const Objlist_Entry *elm;
2084 if (root->dag_inited)
2086 donelist_init(&donelist);
2088 /* Root object belongs to own DAG. */
2089 objlist_push_tail(&root->dldags, root);
2090 objlist_push_tail(&root->dagmembers, root);
2091 donelist_check(&donelist, root);
2094 * Add dependencies of root object to DAG in breadth order
2095 * by exploiting the fact that each new object get added
2096 * to the tail of the dagmembers list.
2098 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2099 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
2100 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
2102 objlist_push_tail(&needed->obj->dldags, root);
2103 objlist_push_tail(&root->dagmembers, needed->obj);
2106 root->dag_inited = true;
2110 init_marker(Obj_Entry *marker)
2113 bzero(marker, sizeof(*marker));
2114 marker->marker = true;
2118 globallist_curr(const Obj_Entry *obj)
2125 return (__DECONST(Obj_Entry *, obj));
2126 obj = TAILQ_PREV(obj, obj_entry_q, next);
2131 globallist_next(const Obj_Entry *obj)
2135 obj = TAILQ_NEXT(obj, next);
2139 return (__DECONST(Obj_Entry *, obj));
2143 /* Prevent the object from being unmapped while the bind lock is dropped. */
2145 hold_object(Obj_Entry *obj)
2152 unhold_object(Obj_Entry *obj)
2155 assert(obj->holdcount > 0);
2156 if (--obj->holdcount == 0 && obj->unholdfree)
2157 release_object(obj);
2161 process_z(Obj_Entry *root)
2163 const Objlist_Entry *elm;
2167 * Walk over object DAG and process every dependent object
2168 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2169 * to grow their own DAG.
2171 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2172 * symlook_global() to work.
2174 * For DF_1_NODELETE, the DAG should have its reference upped.
2176 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2180 if (obj->z_nodelete && !obj->ref_nodel) {
2181 dbg("obj %s -z nodelete", obj->path);
2184 obj->ref_nodel = true;
2186 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2187 dbg("obj %s -z global", obj->path);
2188 objlist_push_tail(&list_global, obj);
2195 parse_rtld_phdr(Obj_Entry *obj)
2198 Elf_Addr note_start, note_end;
2200 obj->stack_flags = PF_X | PF_R | PF_W;
2201 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr +
2202 obj->phsize; ph++) {
2203 switch (ph->p_type) {
2205 obj->stack_flags = ph->p_flags;
2208 obj->relro_page = obj->relocbase +
2209 trunc_page(ph->p_vaddr);
2210 obj->relro_size = round_page(ph->p_memsz);
2213 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
2214 note_end = note_start + ph->p_filesz;
2215 digest_notes(obj, note_start, note_end);
2222 * Initialize the dynamic linker. The argument is the address at which
2223 * the dynamic linker has been mapped into memory. The primary task of
2224 * this function is to relocate the dynamic linker.
2227 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2229 Obj_Entry objtmp; /* Temporary rtld object */
2230 const Elf_Ehdr *ehdr;
2231 const Elf_Dyn *dyn_rpath;
2232 const Elf_Dyn *dyn_soname;
2233 const Elf_Dyn *dyn_runpath;
2235 #ifdef RTLD_INIT_PAGESIZES_EARLY
2236 /* The page size is required by the dynamic memory allocator. */
2237 init_pagesizes(aux_info);
2241 * Conjure up an Obj_Entry structure for the dynamic linker.
2243 * The "path" member can't be initialized yet because string constants
2244 * cannot yet be accessed. Below we will set it correctly.
2246 memset(&objtmp, 0, sizeof(objtmp));
2249 objtmp.mapbase = mapbase;
2251 objtmp.relocbase = mapbase;
2254 objtmp.dynamic = rtld_dynamic(&objtmp);
2255 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2256 assert(objtmp.needed == NULL);
2257 #if !defined(__mips__)
2258 /* MIPS has a bogus DT_TEXTREL. */
2259 assert(!objtmp.textrel);
2262 * Temporarily put the dynamic linker entry into the object list, so
2263 * that symbols can be found.
2265 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2267 ehdr = (Elf_Ehdr *)mapbase;
2268 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2269 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2271 /* Initialize the object list. */
2272 TAILQ_INIT(&obj_list);
2274 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2275 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2277 #ifndef RTLD_INIT_PAGESIZES_EARLY
2278 /* The page size is required by the dynamic memory allocator. */
2279 init_pagesizes(aux_info);
2282 if (aux_info[AT_OSRELDATE] != NULL)
2283 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2285 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2287 /* Replace the path with a dynamically allocated copy. */
2288 obj_rtld.path = xstrdup(ld_path_rtld);
2290 parse_rtld_phdr(&obj_rtld);
2291 obj_enforce_relro(&obj_rtld);
2293 r_debug.r_version = R_DEBUG_VERSION;
2294 r_debug.r_brk = r_debug_state;
2295 r_debug.r_state = RT_CONSISTENT;
2296 r_debug.r_ldbase = obj_rtld.relocbase;
2300 * Retrieve the array of supported page sizes. The kernel provides the page
2301 * sizes in increasing order.
2304 init_pagesizes(Elf_Auxinfo **aux_info)
2306 static size_t psa[MAXPAGESIZES];
2310 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2312 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2313 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2316 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2319 /* As a fallback, retrieve the base page size. */
2320 size = sizeof(psa[0]);
2321 if (aux_info[AT_PAGESZ] != NULL) {
2322 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2326 mib[1] = HW_PAGESIZE;
2330 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2331 _rtld_error("sysctl for hw.pagesize(s) failed");
2337 npagesizes = size / sizeof(pagesizes[0]);
2338 /* Discard any invalid entries at the end of the array. */
2339 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2344 * Add the init functions from a needed object list (and its recursive
2345 * needed objects) to "list". This is not used directly; it is a helper
2346 * function for initlist_add_objects(). The write lock must be held
2347 * when this function is called.
2350 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2352 /* Recursively process the successor needed objects. */
2353 if (needed->next != NULL)
2354 initlist_add_neededs(needed->next, list);
2356 /* Process the current needed object. */
2357 if (needed->obj != NULL)
2358 initlist_add_objects(needed->obj, needed->obj, list);
2362 * Scan all of the DAGs rooted in the range of objects from "obj" to
2363 * "tail" and add their init functions to "list". This recurses over
2364 * the DAGs and ensure the proper init ordering such that each object's
2365 * needed libraries are initialized before the object itself. At the
2366 * same time, this function adds the objects to the global finalization
2367 * list "list_fini" in the opposite order. The write lock must be
2368 * held when this function is called.
2371 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2375 if (obj->init_scanned || obj->init_done)
2377 obj->init_scanned = true;
2379 /* Recursively process the successor objects. */
2380 nobj = globallist_next(obj);
2381 if (nobj != NULL && obj != tail)
2382 initlist_add_objects(nobj, tail, list);
2384 /* Recursively process the needed objects. */
2385 if (obj->needed != NULL)
2386 initlist_add_neededs(obj->needed, list);
2387 if (obj->needed_filtees != NULL)
2388 initlist_add_neededs(obj->needed_filtees, list);
2389 if (obj->needed_aux_filtees != NULL)
2390 initlist_add_neededs(obj->needed_aux_filtees, list);
2392 /* Add the object to the init list. */
2393 objlist_push_tail(list, obj);
2395 /* Add the object to the global fini list in the reverse order. */
2396 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2397 && !obj->on_fini_list) {
2398 objlist_push_head(&list_fini, obj);
2399 obj->on_fini_list = true;
2404 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2408 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2410 Needed_Entry *needed, *needed1;
2412 for (needed = n; needed != NULL; needed = needed->next) {
2413 if (needed->obj != NULL) {
2414 dlclose_locked(needed->obj, lockstate);
2418 for (needed = n; needed != NULL; needed = needed1) {
2419 needed1 = needed->next;
2425 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2428 free_needed_filtees(obj->needed_filtees, lockstate);
2429 obj->needed_filtees = NULL;
2430 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2431 obj->needed_aux_filtees = NULL;
2432 obj->filtees_loaded = false;
2436 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2437 RtldLockState *lockstate)
2440 for (; needed != NULL; needed = needed->next) {
2441 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2442 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2443 RTLD_LOCAL, lockstate);
2448 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2451 lock_restart_for_upgrade(lockstate);
2452 if (!obj->filtees_loaded) {
2453 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2454 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2455 obj->filtees_loaded = true;
2460 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2464 for (; needed != NULL; needed = needed->next) {
2465 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2466 flags & ~RTLD_LO_NOLOAD);
2467 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2474 * Given a shared object, traverse its list of needed objects, and load
2475 * each of them. Returns 0 on success. Generates an error message and
2476 * returns -1 on failure.
2479 load_needed_objects(Obj_Entry *first, int flags)
2483 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2486 if (process_needed(obj, obj->needed, flags) == -1)
2493 load_preload_objects(char *p, bool isfd)
2496 static const char delim[] = " \t:;";
2501 p += strspn(p, delim);
2502 while (*p != '\0') {
2504 size_t len = strcspn(p, delim);
2512 fd = parse_integer(p);
2520 obj = load_object(name, fd, NULL, 0);
2522 return (-1); /* XXX - cleanup */
2523 obj->z_interpose = true;
2526 p += strspn(p, delim);
2528 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2534 printable_path(const char *path)
2537 return (path == NULL ? "<unknown>" : path);
2541 * Load a shared object into memory, if it is not already loaded. The
2542 * object may be specified by name or by user-supplied file descriptor
2543 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2546 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2550 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2559 TAILQ_FOREACH(obj, &obj_list, next) {
2560 if (obj->marker || obj->doomed)
2562 if (object_match_name(obj, name))
2566 path = find_library(name, refobj, &fd);
2574 * search_library_pathfds() opens a fresh file descriptor for the
2575 * library, so there is no need to dup().
2577 } else if (fd_u == -1) {
2579 * If we didn't find a match by pathname, or the name is not
2580 * supplied, open the file and check again by device and inode.
2581 * This avoids false mismatches caused by multiple links or ".."
2584 * To avoid a race, we open the file and use fstat() rather than
2587 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2588 _rtld_error("Cannot open \"%s\"", path);
2593 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2595 _rtld_error("Cannot dup fd");
2600 if (fstat(fd, &sb) == -1) {
2601 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2606 TAILQ_FOREACH(obj, &obj_list, next) {
2607 if (obj->marker || obj->doomed)
2609 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2612 if (obj != NULL && name != NULL) {
2613 object_add_name(obj, name);
2618 if (flags & RTLD_LO_NOLOAD) {
2624 /* First use of this object, so we must map it in */
2625 obj = do_load_object(fd, name, path, &sb, flags);
2634 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2641 * but first, make sure that environment variables haven't been
2642 * used to circumvent the noexec flag on a filesystem.
2644 if (dangerous_ld_env) {
2645 if (fstatfs(fd, &fs) != 0) {
2646 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2649 if (fs.f_flags & MNT_NOEXEC) {
2650 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2654 dbg("loading \"%s\"", printable_path(path));
2655 obj = map_object(fd, printable_path(path), sbp);
2660 * If DT_SONAME is present in the object, digest_dynamic2 already
2661 * added it to the object names.
2664 object_add_name(obj, name);
2666 if (!digest_dynamic(obj, 0))
2668 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2669 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2670 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) {
2671 dbg("refusing to load PIE executable \"%s\"", obj->path);
2672 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
2675 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2677 dbg("refusing to load non-loadable \"%s\"", obj->path);
2678 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2682 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2683 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2686 linkmap_add(obj); /* for GDB & dlinfo() */
2687 max_stack_flags |= obj->stack_flags;
2689 dbg(" %p .. %p: %s", obj->mapbase,
2690 obj->mapbase + obj->mapsize - 1, obj->path);
2692 dbg(" WARNING: %s has impure text", obj->path);
2693 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2699 munmap(obj->mapbase, obj->mapsize);
2705 obj_from_addr(const void *addr)
2709 TAILQ_FOREACH(obj, &obj_list, next) {
2712 if (addr < (void *) obj->mapbase)
2714 if (addr < (void *)(obj->mapbase + obj->mapsize))
2723 Elf_Addr *preinit_addr;
2726 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2727 if (preinit_addr == NULL)
2730 for (index = 0; index < obj_main->preinit_array_num; index++) {
2731 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2732 dbg("calling preinit function for %s at %p", obj_main->path,
2733 (void *)preinit_addr[index]);
2734 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2735 0, 0, obj_main->path);
2736 call_init_pointer(obj_main, preinit_addr[index]);
2742 * Call the finalization functions for each of the objects in "list"
2743 * belonging to the DAG of "root" and referenced once. If NULL "root"
2744 * is specified, every finalization function will be called regardless
2745 * of the reference count and the list elements won't be freed. All of
2746 * the objects are expected to have non-NULL fini functions.
2749 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2752 struct dlerror_save *saved_msg;
2753 Elf_Addr *fini_addr;
2756 assert(root == NULL || root->refcount == 1);
2759 root->doomed = true;
2762 * Preserve the current error message since a fini function might
2763 * call into the dynamic linker and overwrite it.
2765 saved_msg = errmsg_save();
2767 STAILQ_FOREACH(elm, list, link) {
2768 if (root != NULL && (elm->obj->refcount != 1 ||
2769 objlist_find(&root->dagmembers, elm->obj) == NULL))
2771 /* Remove object from fini list to prevent recursive invocation. */
2772 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2773 /* Ensure that new references cannot be acquired. */
2774 elm->obj->doomed = true;
2776 hold_object(elm->obj);
2777 lock_release(rtld_bind_lock, lockstate);
2779 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2780 * When this happens, DT_FINI_ARRAY is processed first.
2782 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2783 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2784 for (index = elm->obj->fini_array_num - 1; index >= 0;
2786 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2787 dbg("calling fini function for %s at %p",
2788 elm->obj->path, (void *)fini_addr[index]);
2789 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2790 (void *)fini_addr[index], 0, 0, elm->obj->path);
2791 call_initfini_pointer(elm->obj, fini_addr[index]);
2795 if (elm->obj->fini != (Elf_Addr)NULL) {
2796 dbg("calling fini function for %s at %p", elm->obj->path,
2797 (void *)elm->obj->fini);
2798 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2799 0, 0, elm->obj->path);
2800 call_initfini_pointer(elm->obj, elm->obj->fini);
2802 wlock_acquire(rtld_bind_lock, lockstate);
2803 unhold_object(elm->obj);
2804 /* No need to free anything if process is going down. */
2808 * We must restart the list traversal after every fini call
2809 * because a dlclose() call from the fini function or from
2810 * another thread might have modified the reference counts.
2814 } while (elm != NULL);
2815 errmsg_restore(saved_msg);
2819 * Call the initialization functions for each of the objects in
2820 * "list". All of the objects are expected to have non-NULL init
2824 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2828 struct dlerror_save *saved_msg;
2829 Elf_Addr *init_addr;
2830 void (*reg)(void (*)(void));
2834 * Clean init_scanned flag so that objects can be rechecked and
2835 * possibly initialized earlier if any of vectors called below
2836 * cause the change by using dlopen.
2838 TAILQ_FOREACH(obj, &obj_list, next) {
2841 obj->init_scanned = false;
2845 * Preserve the current error message since an init function might
2846 * call into the dynamic linker and overwrite it.
2848 saved_msg = errmsg_save();
2849 STAILQ_FOREACH(elm, list, link) {
2850 if (elm->obj->init_done) /* Initialized early. */
2853 * Race: other thread might try to use this object before current
2854 * one completes the initialization. Not much can be done here
2855 * without better locking.
2857 elm->obj->init_done = true;
2858 hold_object(elm->obj);
2860 if (elm->obj == obj_main && obj_main->crt_no_init) {
2861 reg = (void (*)(void (*)(void)))get_program_var_addr(
2862 "__libc_atexit", lockstate);
2864 lock_release(rtld_bind_lock, lockstate);
2867 rtld_exit_ptr = rtld_nop_exit;
2871 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2872 * When this happens, DT_INIT is processed first.
2874 if (elm->obj->init != (Elf_Addr)NULL) {
2875 dbg("calling init function for %s at %p", elm->obj->path,
2876 (void *)elm->obj->init);
2877 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2878 0, 0, elm->obj->path);
2879 call_init_pointer(elm->obj, elm->obj->init);
2881 init_addr = (Elf_Addr *)elm->obj->init_array;
2882 if (init_addr != NULL) {
2883 for (index = 0; index < elm->obj->init_array_num; index++) {
2884 if (init_addr[index] != 0 && init_addr[index] != 1) {
2885 dbg("calling init function for %s at %p", elm->obj->path,
2886 (void *)init_addr[index]);
2887 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2888 (void *)init_addr[index], 0, 0, elm->obj->path);
2889 call_init_pointer(elm->obj, init_addr[index]);
2893 wlock_acquire(rtld_bind_lock, lockstate);
2894 unhold_object(elm->obj);
2896 errmsg_restore(saved_msg);
2900 objlist_clear(Objlist *list)
2904 while (!STAILQ_EMPTY(list)) {
2905 elm = STAILQ_FIRST(list);
2906 STAILQ_REMOVE_HEAD(list, link);
2911 static Objlist_Entry *
2912 objlist_find(Objlist *list, const Obj_Entry *obj)
2916 STAILQ_FOREACH(elm, list, link)
2917 if (elm->obj == obj)
2923 objlist_init(Objlist *list)
2929 objlist_push_head(Objlist *list, Obj_Entry *obj)
2933 elm = NEW(Objlist_Entry);
2935 STAILQ_INSERT_HEAD(list, elm, link);
2939 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2943 elm = NEW(Objlist_Entry);
2945 STAILQ_INSERT_TAIL(list, elm, link);
2949 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2951 Objlist_Entry *elm, *listelm;
2953 STAILQ_FOREACH(listelm, list, link) {
2954 if (listelm->obj == listobj)
2957 elm = NEW(Objlist_Entry);
2959 if (listelm != NULL)
2960 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2962 STAILQ_INSERT_TAIL(list, elm, link);
2966 objlist_remove(Objlist *list, Obj_Entry *obj)
2970 if ((elm = objlist_find(list, obj)) != NULL) {
2971 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2977 * Relocate dag rooted in the specified object.
2978 * Returns 0 on success, or -1 on failure.
2982 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2983 int flags, RtldLockState *lockstate)
2989 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2990 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2999 * Prepare for, or clean after, relocating an object marked with
3000 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
3001 * segments are remapped read-write. After relocations are done, the
3002 * segment's permissions are returned back to the modes specified in
3003 * the phdrs. If any relocation happened, or always for wired
3004 * program, COW is triggered.
3007 reloc_textrel_prot(Obj_Entry *obj, bool before)
3014 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
3016 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
3018 base = obj->relocbase + trunc_page(ph->p_vaddr);
3019 sz = round_page(ph->p_vaddr + ph->p_filesz) -
3020 trunc_page(ph->p_vaddr);
3021 prot = before ? (PROT_READ | PROT_WRITE) :
3022 convert_prot(ph->p_flags);
3023 if (mprotect(base, sz, prot) == -1) {
3024 _rtld_error("%s: Cannot write-%sable text segment: %s",
3025 obj->path, before ? "en" : "dis",
3026 rtld_strerror(errno));
3034 * Relocate single object.
3035 * Returns 0 on success, or -1 on failure.
3038 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
3039 int flags, RtldLockState *lockstate)
3044 obj->relocated = true;
3046 dbg("relocating \"%s\"", obj->path);
3048 if (obj->symtab == NULL || obj->strtab == NULL ||
3049 !(obj->valid_hash_sysv || obj->valid_hash_gnu))
3050 dbg("object %s has no run-time symbol table", obj->path);
3052 /* There are relocations to the write-protected text segment. */
3053 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
3056 /* Process the non-PLT non-IFUNC relocations. */
3057 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
3060 /* Re-protected the text segment. */
3061 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
3064 /* Set the special PLT or GOT entries. */
3067 /* Process the PLT relocations. */
3068 if (reloc_plt(obj, flags, lockstate) == -1)
3070 /* Relocate the jump slots if we are doing immediate binding. */
3071 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
3075 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
3079 * Set up the magic number and version in the Obj_Entry. These
3080 * were checked in the crt1.o from the original ElfKit, so we
3081 * set them for backward compatibility.
3083 obj->magic = RTLD_MAGIC;
3084 obj->version = RTLD_VERSION;
3090 * Relocate newly-loaded shared objects. The argument is a pointer to
3091 * the Obj_Entry for the first such object. All objects from the first
3092 * to the end of the list of objects are relocated. Returns 0 on success,
3096 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
3097 int flags, RtldLockState *lockstate)
3102 for (error = 0, obj = first; obj != NULL;
3103 obj = TAILQ_NEXT(obj, next)) {
3106 error = relocate_object(obj, bind_now, rtldobj, flags,
3115 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3116 * referencing STT_GNU_IFUNC symbols is postponed till the other
3117 * relocations are done. The indirect functions specified as
3118 * ifunc are allowed to call other symbols, so we need to have
3119 * objects relocated before asking for resolution from indirects.
3121 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3122 * instead of the usual lazy handling of PLT slots. It is
3123 * consistent with how GNU does it.
3126 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3127 RtldLockState *lockstate)
3130 if (obj->ifuncs_resolved)
3132 obj->ifuncs_resolved = true;
3133 if (!obj->irelative && !obj->irelative_nonplt &&
3134 !((obj->bind_now || bind_now) && obj->gnu_ifunc) &&
3135 !obj->non_plt_gnu_ifunc)
3137 if (obj_disable_relro(obj) == -1 ||
3138 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3139 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj,
3140 lockstate) == -1) ||
3141 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3142 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3143 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld,
3144 flags | SYMLOOK_IFUNC, lockstate) == -1) ||
3145 obj_enforce_relro(obj) == -1)
3151 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3152 RtldLockState *lockstate)
3157 STAILQ_FOREACH(elm, list, link) {
3161 if (resolve_object_ifunc(obj, bind_now, flags,
3169 * Cleanup procedure. It will be called (by the atexit mechanism) just
3170 * before the process exits.
3175 RtldLockState lockstate;
3177 wlock_acquire(rtld_bind_lock, &lockstate);
3179 objlist_call_fini(&list_fini, NULL, &lockstate);
3180 /* No need to remove the items from the list, since we are exiting. */
3181 if (!libmap_disable)
3183 lock_release(rtld_bind_lock, &lockstate);
3192 * Iterate over a search path, translate each element, and invoke the
3193 * callback on the result.
3196 path_enumerate(const char *path, path_enum_proc callback,
3197 const char *refobj_path, void *arg)
3203 path += strspn(path, ":;");
3204 while (*path != '\0') {
3208 len = strcspn(path, ":;");
3209 trans = lm_findn(refobj_path, path, len);
3211 res = callback(trans, strlen(trans), arg);
3213 res = callback(path, len, arg);
3219 path += strspn(path, ":;");
3225 struct try_library_args {
3234 try_library_path(const char *dir, size_t dirlen, void *param)
3236 struct try_library_args *arg;
3240 if (*dir == '/' || trust) {
3243 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3246 pathname = arg->buffer;
3247 strncpy(pathname, dir, dirlen);
3248 pathname[dirlen] = '/';
3249 strcpy(pathname + dirlen + 1, arg->name);
3251 dbg(" Trying \"%s\"", pathname);
3252 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3254 dbg(" Opened \"%s\", fd %d", pathname, fd);
3255 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3256 strcpy(pathname, arg->buffer);
3260 dbg(" Failed to open \"%s\": %s",
3261 pathname, rtld_strerror(errno));
3268 search_library_path(const char *name, const char *path,
3269 const char *refobj_path, int *fdp)
3272 struct try_library_args arg;
3278 arg.namelen = strlen(name);
3279 arg.buffer = xmalloc(PATH_MAX);
3280 arg.buflen = PATH_MAX;
3283 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3293 * Finds the library with the given name using the directory descriptors
3294 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3296 * Returns a freshly-opened close-on-exec file descriptor for the library,
3297 * or -1 if the library cannot be found.
3300 search_library_pathfds(const char *name, const char *path, int *fdp)
3302 char *envcopy, *fdstr, *found, *last_token;
3306 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3308 /* Don't load from user-specified libdirs into setuid binaries. */
3312 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3316 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3317 if (name[0] == '/') {
3318 dbg("Absolute path (%s) passed to %s", name, __func__);
3323 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3324 * copy of the path, as strtok_r rewrites separator tokens
3328 envcopy = xstrdup(path);
3329 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3330 fdstr = strtok_r(NULL, ":", &last_token)) {
3331 dirfd = parse_integer(fdstr);
3333 _rtld_error("failed to parse directory FD: '%s'",
3337 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3340 len = strlen(fdstr) + strlen(name) + 3;
3341 found = xmalloc(len);
3342 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3343 _rtld_error("error generating '%d/%s'",
3347 dbg("open('%s') => %d", found, fd);
3358 dlclose(void *handle)
3360 RtldLockState lockstate;
3363 wlock_acquire(rtld_bind_lock, &lockstate);
3364 error = dlclose_locked(handle, &lockstate);
3365 lock_release(rtld_bind_lock, &lockstate);
3370 dlclose_locked(void *handle, RtldLockState *lockstate)
3374 root = dlcheck(handle);
3377 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3380 /* Unreference the object and its dependencies. */
3381 root->dl_refcount--;
3383 if (root->refcount == 1) {
3385 * The object will be no longer referenced, so we must unload it.
3386 * First, call the fini functions.
3388 objlist_call_fini(&list_fini, root, lockstate);
3392 /* Finish cleaning up the newly-unreferenced objects. */
3393 GDB_STATE(RT_DELETE,&root->linkmap);
3394 unload_object(root, lockstate);
3395 GDB_STATE(RT_CONSISTENT,NULL);
3399 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3406 if (*(lockinfo.dlerror_seen()) != 0)
3408 *lockinfo.dlerror_seen() = 1;
3409 return (lockinfo.dlerror_loc());
3413 * This function is deprecated and has no effect.
3416 dllockinit(void *context,
3417 void *(*_lock_create)(void *context) __unused,
3418 void (*_rlock_acquire)(void *lock) __unused,
3419 void (*_wlock_acquire)(void *lock) __unused,
3420 void (*_lock_release)(void *lock) __unused,
3421 void (*_lock_destroy)(void *lock) __unused,
3422 void (*context_destroy)(void *context))
3424 static void *cur_context;
3425 static void (*cur_context_destroy)(void *);
3427 /* Just destroy the context from the previous call, if necessary. */
3428 if (cur_context_destroy != NULL)
3429 cur_context_destroy(cur_context);
3430 cur_context = context;
3431 cur_context_destroy = context_destroy;
3435 dlopen(const char *name, int mode)
3438 return (rtld_dlopen(name, -1, mode));
3442 fdlopen(int fd, int mode)
3445 return (rtld_dlopen(NULL, fd, mode));
3449 rtld_dlopen(const char *name, int fd, int mode)
3451 RtldLockState lockstate;
3454 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3455 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3456 if (ld_tracing != NULL) {
3457 rlock_acquire(rtld_bind_lock, &lockstate);
3458 if (sigsetjmp(lockstate.env, 0) != 0)
3459 lock_upgrade(rtld_bind_lock, &lockstate);
3460 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3461 lock_release(rtld_bind_lock, &lockstate);
3463 lo_flags = RTLD_LO_DLOPEN;
3464 if (mode & RTLD_NODELETE)
3465 lo_flags |= RTLD_LO_NODELETE;
3466 if (mode & RTLD_NOLOAD)
3467 lo_flags |= RTLD_LO_NOLOAD;
3468 if (mode & RTLD_DEEPBIND)
3469 lo_flags |= RTLD_LO_DEEPBIND;
3470 if (ld_tracing != NULL)
3471 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3473 return (dlopen_object(name, fd, obj_main, lo_flags,
3474 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3478 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3483 if (obj->refcount == 0)
3484 unload_object(obj, lockstate);
3488 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3489 int mode, RtldLockState *lockstate)
3491 Obj_Entry *old_obj_tail;
3494 RtldLockState mlockstate;
3497 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x",
3498 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" :
3499 refobj->path, lo_flags, mode);
3500 objlist_init(&initlist);
3502 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3503 wlock_acquire(rtld_bind_lock, &mlockstate);
3504 lockstate = &mlockstate;
3506 GDB_STATE(RT_ADD,NULL);
3508 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3510 if (name == NULL && fd == -1) {
3514 obj = load_object(name, fd, refobj, lo_flags);
3519 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3520 objlist_push_tail(&list_global, obj);
3521 if (globallist_next(old_obj_tail) != NULL) {
3522 /* We loaded something new. */
3523 assert(globallist_next(old_obj_tail) == obj);
3524 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
3525 obj->symbolic = true;
3527 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 &&
3528 obj->static_tls && !allocate_tls_offset(obj)) {
3529 _rtld_error("%s: No space available "
3530 "for static Thread Local Storage", obj->path);
3534 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3535 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE));
3539 result = rtld_verify_versions(&obj->dagmembers);
3540 if (result != -1 && ld_tracing)
3542 if (result == -1 || relocate_object_dag(obj,
3543 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3544 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3546 dlopen_cleanup(obj, lockstate);
3548 } else if (lo_flags & RTLD_LO_EARLY) {
3550 * Do not call the init functions for early loaded
3551 * filtees. The image is still not initialized enough
3554 * Our object is found by the global object list and
3555 * will be ordered among all init calls done right
3556 * before transferring control to main.
3559 /* Make list of init functions to call. */
3560 initlist_add_objects(obj, obj, &initlist);
3563 * Process all no_delete or global objects here, given
3564 * them own DAGs to prevent their dependencies from being
3565 * unloaded. This has to be done after we have loaded all
3566 * of the dependencies, so that we do not miss any.
3572 * Bump the reference counts for objects on this DAG. If
3573 * this is the first dlopen() call for the object that was
3574 * already loaded as a dependency, initialize the dag
3580 if ((lo_flags & RTLD_LO_TRACE) != 0)
3583 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3584 obj->z_nodelete) && !obj->ref_nodel) {
3585 dbg("obj %s nodelete", obj->path);
3587 obj->z_nodelete = obj->ref_nodel = true;
3591 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3593 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3595 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3596 map_stacks_exec(lockstate);
3598 distribute_static_tls(&initlist, lockstate);
3601 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3602 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3604 objlist_clear(&initlist);
3605 dlopen_cleanup(obj, lockstate);
3606 if (lockstate == &mlockstate)
3607 lock_release(rtld_bind_lock, lockstate);
3611 if (!(lo_flags & RTLD_LO_EARLY)) {
3612 /* Call the init functions. */
3613 objlist_call_init(&initlist, lockstate);
3615 objlist_clear(&initlist);
3616 if (lockstate == &mlockstate)
3617 lock_release(rtld_bind_lock, lockstate);
3620 trace_loaded_objects(obj);
3621 if (lockstate == &mlockstate)
3622 lock_release(rtld_bind_lock, lockstate);
3627 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3631 const Obj_Entry *obj, *defobj;
3634 RtldLockState lockstate;
3641 symlook_init(&req, name);
3643 req.flags = flags | SYMLOOK_IN_PLT;
3644 req.lockstate = &lockstate;
3646 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3647 rlock_acquire(rtld_bind_lock, &lockstate);
3648 if (sigsetjmp(lockstate.env, 0) != 0)
3649 lock_upgrade(rtld_bind_lock, &lockstate);
3650 if (handle == NULL || handle == RTLD_NEXT ||
3651 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3653 if ((obj = obj_from_addr(retaddr)) == NULL) {
3654 _rtld_error("Cannot determine caller's shared object");
3655 lock_release(rtld_bind_lock, &lockstate);
3656 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3659 if (handle == NULL) { /* Just the caller's shared object. */
3660 res = symlook_obj(&req, obj);
3663 defobj = req.defobj_out;
3665 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3666 handle == RTLD_SELF) { /* ... caller included */
3667 if (handle == RTLD_NEXT)
3668 obj = globallist_next(obj);
3669 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3672 res = symlook_obj(&req, obj);
3675 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3677 defobj = req.defobj_out;
3678 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3684 * Search the dynamic linker itself, and possibly resolve the
3685 * symbol from there. This is how the application links to
3686 * dynamic linker services such as dlopen.
3688 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3689 res = symlook_obj(&req, &obj_rtld);
3692 defobj = req.defobj_out;
3696 assert(handle == RTLD_DEFAULT);
3697 res = symlook_default(&req, obj);
3699 defobj = req.defobj_out;
3704 if ((obj = dlcheck(handle)) == NULL) {
3705 lock_release(rtld_bind_lock, &lockstate);
3706 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3710 donelist_init(&donelist);
3711 if (obj->mainprog) {
3712 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3713 res = symlook_global(&req, &donelist);
3716 defobj = req.defobj_out;
3719 * Search the dynamic linker itself, and possibly resolve the
3720 * symbol from there. This is how the application links to
3721 * dynamic linker services such as dlopen.
3723 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3724 res = symlook_obj(&req, &obj_rtld);
3727 defobj = req.defobj_out;
3732 /* Search the whole DAG rooted at the given object. */
3733 res = symlook_list(&req, &obj->dagmembers, &donelist);
3736 defobj = req.defobj_out;
3742 lock_release(rtld_bind_lock, &lockstate);
3745 * The value required by the caller is derived from the value
3746 * of the symbol. this is simply the relocated value of the
3749 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3750 sym = make_function_pointer(def, defobj);
3751 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3752 sym = rtld_resolve_ifunc(defobj, def);
3753 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3754 ti.ti_module = defobj->tlsindex;
3755 ti.ti_offset = def->st_value;
3756 sym = __tls_get_addr(&ti);
3758 sym = defobj->relocbase + def->st_value;
3759 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3763 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3764 ve != NULL ? ve->name : "");
3765 lock_release(rtld_bind_lock, &lockstate);
3766 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3771 dlsym(void *handle, const char *name)
3773 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3778 dlfunc(void *handle, const char *name)
3785 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3791 dlvsym(void *handle, const char *name, const char *version)
3795 ventry.name = version;
3797 ventry.hash = elf_hash(version);
3799 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3804 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3806 const Obj_Entry *obj;
3807 RtldLockState lockstate;
3809 rlock_acquire(rtld_bind_lock, &lockstate);
3810 obj = obj_from_addr(addr);
3812 _rtld_error("No shared object contains address");
3813 lock_release(rtld_bind_lock, &lockstate);
3816 rtld_fill_dl_phdr_info(obj, phdr_info);
3817 lock_release(rtld_bind_lock, &lockstate);
3822 dladdr(const void *addr, Dl_info *info)
3824 const Obj_Entry *obj;
3827 unsigned long symoffset;
3828 RtldLockState lockstate;
3830 rlock_acquire(rtld_bind_lock, &lockstate);
3831 obj = obj_from_addr(addr);
3833 _rtld_error("No shared object contains address");
3834 lock_release(rtld_bind_lock, &lockstate);
3837 info->dli_fname = obj->path;
3838 info->dli_fbase = obj->mapbase;
3839 info->dli_saddr = (void *)0;
3840 info->dli_sname = NULL;
3843 * Walk the symbol list looking for the symbol whose address is
3844 * closest to the address sent in.
3846 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3847 def = obj->symtab + symoffset;
3850 * For skip the symbol if st_shndx is either SHN_UNDEF or
3853 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3857 * If the symbol is greater than the specified address, or if it
3858 * is further away from addr than the current nearest symbol,
3861 symbol_addr = obj->relocbase + def->st_value;
3862 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3865 /* Update our idea of the nearest symbol. */
3866 info->dli_sname = obj->strtab + def->st_name;
3867 info->dli_saddr = symbol_addr;
3870 if (info->dli_saddr == addr)
3873 lock_release(rtld_bind_lock, &lockstate);
3878 dlinfo(void *handle, int request, void *p)
3880 const Obj_Entry *obj;
3881 RtldLockState lockstate;
3884 rlock_acquire(rtld_bind_lock, &lockstate);
3886 if (handle == NULL || handle == RTLD_SELF) {
3889 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3890 if ((obj = obj_from_addr(retaddr)) == NULL)
3891 _rtld_error("Cannot determine caller's shared object");
3893 obj = dlcheck(handle);
3896 lock_release(rtld_bind_lock, &lockstate);
3902 case RTLD_DI_LINKMAP:
3903 *((struct link_map const **)p) = &obj->linkmap;
3905 case RTLD_DI_ORIGIN:
3906 error = rtld_dirname(obj->path, p);
3909 case RTLD_DI_SERINFOSIZE:
3910 case RTLD_DI_SERINFO:
3911 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3915 _rtld_error("Invalid request %d passed to dlinfo()", request);
3919 lock_release(rtld_bind_lock, &lockstate);
3925 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3929 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3930 phdr_info->dlpi_name = obj->path;
3931 phdr_info->dlpi_phdr = obj->phdr;
3932 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3933 phdr_info->dlpi_tls_modid = obj->tlsindex;
3935 phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(dtvp,
3936 obj->tlsindex, 0, true) + TLS_DTV_OFFSET;
3937 phdr_info->dlpi_adds = obj_loads;
3938 phdr_info->dlpi_subs = obj_loads - obj_count;
3942 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3944 struct dl_phdr_info phdr_info;
3945 Obj_Entry *obj, marker;
3946 RtldLockState bind_lockstate, phdr_lockstate;
3949 init_marker(&marker);
3952 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3953 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3954 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3955 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3956 rtld_fill_dl_phdr_info(obj, &phdr_info);
3958 lock_release(rtld_bind_lock, &bind_lockstate);
3960 error = callback(&phdr_info, sizeof phdr_info, param);
3962 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3964 obj = globallist_next(&marker);
3965 TAILQ_REMOVE(&obj_list, &marker, next);
3967 lock_release(rtld_bind_lock, &bind_lockstate);
3968 lock_release(rtld_phdr_lock, &phdr_lockstate);
3974 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3975 lock_release(rtld_bind_lock, &bind_lockstate);
3976 error = callback(&phdr_info, sizeof(phdr_info), param);
3978 lock_release(rtld_phdr_lock, &phdr_lockstate);
3983 fill_search_info(const char *dir, size_t dirlen, void *param)
3985 struct fill_search_info_args *arg;
3989 if (arg->request == RTLD_DI_SERINFOSIZE) {
3990 arg->serinfo->dls_cnt ++;
3991 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3993 struct dl_serpath *s_entry;
3995 s_entry = arg->serpath;
3996 s_entry->dls_name = arg->strspace;
3997 s_entry->dls_flags = arg->flags;
3999 strncpy(arg->strspace, dir, dirlen);
4000 arg->strspace[dirlen] = '\0';
4002 arg->strspace += dirlen + 1;
4010 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
4012 struct dl_serinfo _info;
4013 struct fill_search_info_args args;
4015 args.request = RTLD_DI_SERINFOSIZE;
4016 args.serinfo = &_info;
4018 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
4021 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
4022 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
4023 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
4024 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
4025 if (!obj->z_nodeflib)
4026 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
4029 if (request == RTLD_DI_SERINFOSIZE) {
4030 info->dls_size = _info.dls_size;
4031 info->dls_cnt = _info.dls_cnt;
4035 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
4036 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
4040 args.request = RTLD_DI_SERINFO;
4041 args.serinfo = info;
4042 args.serpath = &info->dls_serpath[0];
4043 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
4045 args.flags = LA_SER_RUNPATH;
4046 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
4049 args.flags = LA_SER_LIBPATH;
4050 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
4053 args.flags = LA_SER_RUNPATH;
4054 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
4057 args.flags = LA_SER_CONFIG;
4058 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
4062 args.flags = LA_SER_DEFAULT;
4063 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
4064 fill_search_info, NULL, &args) != NULL)
4070 rtld_dirname(const char *path, char *bname)
4074 /* Empty or NULL string gets treated as "." */
4075 if (path == NULL || *path == '\0') {
4081 /* Strip trailing slashes */
4082 endp = path + strlen(path) - 1;
4083 while (endp > path && *endp == '/')
4086 /* Find the start of the dir */
4087 while (endp > path && *endp != '/')
4090 /* Either the dir is "/" or there are no slashes */
4092 bname[0] = *endp == '/' ? '/' : '.';
4098 } while (endp > path && *endp == '/');
4101 if (endp - path + 2 > PATH_MAX)
4103 _rtld_error("Filename is too long: %s", path);
4107 strncpy(bname, path, endp - path + 1);
4108 bname[endp - path + 1] = '\0';
4113 rtld_dirname_abs(const char *path, char *base)
4117 if (realpath(path, base) == NULL) {
4118 _rtld_error("realpath \"%s\" failed (%s)", path,
4119 rtld_strerror(errno));
4122 dbg("%s -> %s", path, base);
4123 last = strrchr(base, '/');
4125 _rtld_error("non-abs result from realpath \"%s\"", path);
4134 linkmap_add(Obj_Entry *obj)
4136 struct link_map *l, *prev;
4139 l->l_name = obj->path;
4140 l->l_base = obj->mapbase;
4141 l->l_ld = obj->dynamic;
4142 l->l_addr = obj->relocbase;
4144 if (r_debug.r_map == NULL) {
4150 * Scan to the end of the list, but not past the entry for the
4151 * dynamic linker, which we want to keep at the very end.
4153 for (prev = r_debug.r_map;
4154 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4155 prev = prev->l_next)
4158 /* Link in the new entry. */
4160 l->l_next = prev->l_next;
4161 if (l->l_next != NULL)
4162 l->l_next->l_prev = l;
4167 linkmap_delete(Obj_Entry *obj)
4172 if (l->l_prev == NULL) {
4173 if ((r_debug.r_map = l->l_next) != NULL)
4174 l->l_next->l_prev = NULL;
4178 if ((l->l_prev->l_next = l->l_next) != NULL)
4179 l->l_next->l_prev = l->l_prev;
4183 * Function for the debugger to set a breakpoint on to gain control.
4185 * The two parameters allow the debugger to easily find and determine
4186 * what the runtime loader is doing and to whom it is doing it.
4188 * When the loadhook trap is hit (r_debug_state, set at program
4189 * initialization), the arguments can be found on the stack:
4191 * +8 struct link_map *m
4192 * +4 struct r_debug *rd
4196 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4199 * The following is a hack to force the compiler to emit calls to
4200 * this function, even when optimizing. If the function is empty,
4201 * the compiler is not obliged to emit any code for calls to it,
4202 * even when marked __noinline. However, gdb depends on those
4205 __compiler_membar();
4209 * A function called after init routines have completed. This can be used to
4210 * break before a program's entry routine is called, and can be used when
4211 * main is not available in the symbol table.
4214 _r_debug_postinit(struct link_map *m __unused)
4217 /* See r_debug_state(). */
4218 __compiler_membar();
4222 release_object(Obj_Entry *obj)
4225 if (obj->holdcount > 0) {
4226 obj->unholdfree = true;
4229 munmap(obj->mapbase, obj->mapsize);
4230 linkmap_delete(obj);
4235 * Get address of the pointer variable in the main program.
4236 * Prefer non-weak symbol over the weak one.
4238 static const void **
4239 get_program_var_addr(const char *name, RtldLockState *lockstate)
4244 symlook_init(&req, name);
4245 req.lockstate = lockstate;
4246 donelist_init(&donelist);
4247 if (symlook_global(&req, &donelist) != 0)
4249 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4250 return ((const void **)make_function_pointer(req.sym_out,
4252 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4253 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4255 return ((const void **)(req.defobj_out->relocbase +
4256 req.sym_out->st_value));
4260 * Set a pointer variable in the main program to the given value. This
4261 * is used to set key variables such as "environ" before any of the
4262 * init functions are called.
4265 set_program_var(const char *name, const void *value)
4269 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4270 dbg("\"%s\": *%p <-- %p", name, addr, value);
4276 * Search the global objects, including dependencies and main object,
4277 * for the given symbol.
4280 symlook_global(SymLook *req, DoneList *donelist)
4283 const Objlist_Entry *elm;
4286 symlook_init_from_req(&req1, req);
4288 /* Search all objects loaded at program start up. */
4289 if (req->defobj_out == NULL ||
4290 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4291 res = symlook_list(&req1, &list_main, donelist);
4292 if (res == 0 && (req->defobj_out == NULL ||
4293 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4294 req->sym_out = req1.sym_out;
4295 req->defobj_out = req1.defobj_out;
4296 assert(req->defobj_out != NULL);
4300 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4301 STAILQ_FOREACH(elm, &list_global, link) {
4302 if (req->defobj_out != NULL &&
4303 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4305 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4306 if (res == 0 && (req->defobj_out == NULL ||
4307 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4308 req->sym_out = req1.sym_out;
4309 req->defobj_out = req1.defobj_out;
4310 assert(req->defobj_out != NULL);
4314 return (req->sym_out != NULL ? 0 : ESRCH);
4318 * Given a symbol name in a referencing object, find the corresponding
4319 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4320 * no definition was found. Returns a pointer to the Obj_Entry of the
4321 * defining object via the reference parameter DEFOBJ_OUT.
4324 symlook_default(SymLook *req, const Obj_Entry *refobj)
4327 const Objlist_Entry *elm;
4331 donelist_init(&donelist);
4332 symlook_init_from_req(&req1, req);
4335 * Look first in the referencing object if linked symbolically,
4336 * and similarly handle protected symbols.
4338 res = symlook_obj(&req1, refobj);
4339 if (res == 0 && (refobj->symbolic ||
4340 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4341 req->sym_out = req1.sym_out;
4342 req->defobj_out = req1.defobj_out;
4343 assert(req->defobj_out != NULL);
4345 if (refobj->symbolic || req->defobj_out != NULL)
4346 donelist_check(&donelist, refobj);
4348 symlook_global(req, &donelist);
4350 /* Search all dlopened DAGs containing the referencing object. */
4351 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4352 if (req->sym_out != NULL &&
4353 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4355 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4356 if (res == 0 && (req->sym_out == NULL ||
4357 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4358 req->sym_out = req1.sym_out;
4359 req->defobj_out = req1.defobj_out;
4360 assert(req->defobj_out != NULL);
4365 * Search the dynamic linker itself, and possibly resolve the
4366 * symbol from there. This is how the application links to
4367 * dynamic linker services such as dlopen.
4369 if (req->sym_out == NULL ||
4370 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4371 res = symlook_obj(&req1, &obj_rtld);
4373 req->sym_out = req1.sym_out;
4374 req->defobj_out = req1.defobj_out;
4375 assert(req->defobj_out != NULL);
4379 return (req->sym_out != NULL ? 0 : ESRCH);
4383 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4386 const Obj_Entry *defobj;
4387 const Objlist_Entry *elm;
4393 STAILQ_FOREACH(elm, objlist, link) {
4394 if (donelist_check(dlp, elm->obj))
4396 symlook_init_from_req(&req1, req);
4397 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4398 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4400 defobj = req1.defobj_out;
4401 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4408 req->defobj_out = defobj;
4415 * Search the chain of DAGS cointed to by the given Needed_Entry
4416 * for a symbol of the given name. Each DAG is scanned completely
4417 * before advancing to the next one. Returns a pointer to the symbol,
4418 * or NULL if no definition was found.
4421 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4424 const Needed_Entry *n;
4425 const Obj_Entry *defobj;
4431 symlook_init_from_req(&req1, req);
4432 for (n = needed; n != NULL; n = n->next) {
4433 if (n->obj == NULL ||
4434 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4436 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4438 defobj = req1.defobj_out;
4439 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4445 req->defobj_out = defobj;
4452 * Search the symbol table of a single shared object for a symbol of
4453 * the given name and version, if requested. Returns a pointer to the
4454 * symbol, or NULL if no definition was found. If the object is
4455 * filter, return filtered symbol from filtee.
4457 * The symbol's hash value is passed in for efficiency reasons; that
4458 * eliminates many recomputations of the hash value.
4461 symlook_obj(SymLook *req, const Obj_Entry *obj)
4465 int flags, res, mres;
4468 * If there is at least one valid hash at this point, we prefer to
4469 * use the faster GNU version if available.
4471 if (obj->valid_hash_gnu)
4472 mres = symlook_obj1_gnu(req, obj);
4473 else if (obj->valid_hash_sysv)
4474 mres = symlook_obj1_sysv(req, obj);
4479 if (obj->needed_filtees != NULL) {
4480 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4481 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4482 donelist_init(&donelist);
4483 symlook_init_from_req(&req1, req);
4484 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4486 req->sym_out = req1.sym_out;
4487 req->defobj_out = req1.defobj_out;
4491 if (obj->needed_aux_filtees != NULL) {
4492 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4493 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4494 donelist_init(&donelist);
4495 symlook_init_from_req(&req1, req);
4496 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4498 req->sym_out = req1.sym_out;
4499 req->defobj_out = req1.defobj_out;
4507 /* Symbol match routine common to both hash functions */
4509 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4510 const unsigned long symnum)
4513 const Elf_Sym *symp;
4516 symp = obj->symtab + symnum;
4517 strp = obj->strtab + symp->st_name;
4519 switch (ELF_ST_TYPE(symp->st_info)) {
4525 if (symp->st_value == 0)
4529 if (symp->st_shndx != SHN_UNDEF)
4532 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4533 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4540 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4543 if (req->ventry == NULL) {
4544 if (obj->versyms != NULL) {
4545 verndx = VER_NDX(obj->versyms[symnum]);
4546 if (verndx > obj->vernum) {
4548 "%s: symbol %s references wrong version %d",
4549 obj->path, obj->strtab + symnum, verndx);
4553 * If we are not called from dlsym (i.e. this
4554 * is a normal relocation from unversioned
4555 * binary), accept the symbol immediately if
4556 * it happens to have first version after this
4557 * shared object became versioned. Otherwise,
4558 * if symbol is versioned and not hidden,
4559 * remember it. If it is the only symbol with
4560 * this name exported by the shared object, it
4561 * will be returned as a match by the calling
4562 * function. If symbol is global (verndx < 2)
4563 * accept it unconditionally.
4565 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4566 verndx == VER_NDX_GIVEN) {
4567 result->sym_out = symp;
4570 else if (verndx >= VER_NDX_GIVEN) {
4571 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4573 if (result->vsymp == NULL)
4574 result->vsymp = symp;
4580 result->sym_out = symp;
4583 if (obj->versyms == NULL) {
4584 if (object_match_name(obj, req->ventry->name)) {
4585 _rtld_error("%s: object %s should provide version %s "
4586 "for symbol %s", obj_rtld.path, obj->path,
4587 req->ventry->name, obj->strtab + symnum);
4591 verndx = VER_NDX(obj->versyms[symnum]);
4592 if (verndx > obj->vernum) {
4593 _rtld_error("%s: symbol %s references wrong version %d",
4594 obj->path, obj->strtab + symnum, verndx);
4597 if (obj->vertab[verndx].hash != req->ventry->hash ||
4598 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4600 * Version does not match. Look if this is a
4601 * global symbol and if it is not hidden. If
4602 * global symbol (verndx < 2) is available,
4603 * use it. Do not return symbol if we are
4604 * called by dlvsym, because dlvsym looks for
4605 * a specific version and default one is not
4606 * what dlvsym wants.
4608 if ((req->flags & SYMLOOK_DLSYM) ||
4609 (verndx >= VER_NDX_GIVEN) ||
4610 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4614 result->sym_out = symp;
4619 * Search for symbol using SysV hash function.
4620 * obj->buckets is known not to be NULL at this point; the test for this was
4621 * performed with the obj->valid_hash_sysv assignment.
4624 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4626 unsigned long symnum;
4627 Sym_Match_Result matchres;
4629 matchres.sym_out = NULL;
4630 matchres.vsymp = NULL;
4631 matchres.vcount = 0;
4633 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4634 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4635 if (symnum >= obj->nchains)
4636 return (ESRCH); /* Bad object */
4638 if (matched_symbol(req, obj, &matchres, symnum)) {
4639 req->sym_out = matchres.sym_out;
4640 req->defobj_out = obj;
4644 if (matchres.vcount == 1) {
4645 req->sym_out = matchres.vsymp;
4646 req->defobj_out = obj;
4652 /* Search for symbol using GNU hash function */
4654 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4656 Elf_Addr bloom_word;
4657 const Elf32_Word *hashval;
4659 Sym_Match_Result matchres;
4660 unsigned int h1, h2;
4661 unsigned long symnum;
4663 matchres.sym_out = NULL;
4664 matchres.vsymp = NULL;
4665 matchres.vcount = 0;
4667 /* Pick right bitmask word from Bloom filter array */
4668 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4669 obj->maskwords_bm_gnu];
4671 /* Calculate modulus word size of gnu hash and its derivative */
4672 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4673 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4675 /* Filter out the "definitely not in set" queries */
4676 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4679 /* Locate hash chain and corresponding value element*/
4680 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4683 hashval = &obj->chain_zero_gnu[bucket];
4685 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4686 symnum = hashval - obj->chain_zero_gnu;
4687 if (matched_symbol(req, obj, &matchres, symnum)) {
4688 req->sym_out = matchres.sym_out;
4689 req->defobj_out = obj;
4693 } while ((*hashval++ & 1) == 0);
4694 if (matchres.vcount == 1) {
4695 req->sym_out = matchres.vsymp;
4696 req->defobj_out = obj;
4703 trace_loaded_objects(Obj_Entry *obj)
4705 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4708 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4711 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4712 fmt1 = "\t%o => %p (%x)\n";
4714 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4715 fmt2 = "\t%o (%x)\n";
4717 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4719 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4720 Needed_Entry *needed;
4721 const char *name, *path;
4726 if (list_containers && obj->needed != NULL)
4727 rtld_printf("%s:\n", obj->path);
4728 for (needed = obj->needed; needed; needed = needed->next) {
4729 if (needed->obj != NULL) {
4730 if (needed->obj->traced && !list_containers)
4732 needed->obj->traced = true;
4733 path = needed->obj->path;
4737 name = obj->strtab + needed->name;
4738 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4740 fmt = is_lib ? fmt1 : fmt2;
4741 while ((c = *fmt++) != '\0') {
4767 rtld_putstr(main_local);
4770 rtld_putstr(obj_main->path);
4777 rtld_printf("%d", sodp->sod_major);
4780 rtld_printf("%d", sodp->sod_minor);
4787 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4800 * Unload a dlopened object and its dependencies from memory and from
4801 * our data structures. It is assumed that the DAG rooted in the
4802 * object has already been unreferenced, and that the object has a
4803 * reference count of 0.
4806 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4808 Obj_Entry marker, *obj, *next;
4810 assert(root->refcount == 0);
4813 * Pass over the DAG removing unreferenced objects from
4814 * appropriate lists.
4816 unlink_object(root);
4818 /* Unmap all objects that are no longer referenced. */
4819 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4820 next = TAILQ_NEXT(obj, next);
4821 if (obj->marker || obj->refcount != 0)
4823 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4824 obj->mapsize, 0, obj->path);
4825 dbg("unloading \"%s\"", obj->path);
4827 * Unlink the object now to prevent new references from
4828 * being acquired while the bind lock is dropped in
4829 * recursive dlclose() invocations.
4831 TAILQ_REMOVE(&obj_list, obj, next);
4834 if (obj->filtees_loaded) {
4836 init_marker(&marker);
4837 TAILQ_INSERT_BEFORE(next, &marker, next);
4838 unload_filtees(obj, lockstate);
4839 next = TAILQ_NEXT(&marker, next);
4840 TAILQ_REMOVE(&obj_list, &marker, next);
4842 unload_filtees(obj, lockstate);
4844 release_object(obj);
4849 unlink_object(Obj_Entry *root)
4853 if (root->refcount == 0) {
4854 /* Remove the object from the RTLD_GLOBAL list. */
4855 objlist_remove(&list_global, root);
4857 /* Remove the object from all objects' DAG lists. */
4858 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4859 objlist_remove(&elm->obj->dldags, root);
4860 if (elm->obj != root)
4861 unlink_object(elm->obj);
4867 ref_dag(Obj_Entry *root)
4871 assert(root->dag_inited);
4872 STAILQ_FOREACH(elm, &root->dagmembers, link)
4873 elm->obj->refcount++;
4877 unref_dag(Obj_Entry *root)
4881 assert(root->dag_inited);
4882 STAILQ_FOREACH(elm, &root->dagmembers, link)
4883 elm->obj->refcount--;
4887 * Common code for MD __tls_get_addr().
4890 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset, bool locked)
4892 Elf_Addr *newdtv, *dtv;
4893 RtldLockState lockstate;
4897 /* Check dtv generation in case new modules have arrived */
4898 if (dtv[0] != tls_dtv_generation) {
4900 wlock_acquire(rtld_bind_lock, &lockstate);
4901 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4903 if (to_copy > tls_max_index)
4904 to_copy = tls_max_index;
4905 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4906 newdtv[0] = tls_dtv_generation;
4907 newdtv[1] = tls_max_index;
4910 lock_release(rtld_bind_lock, &lockstate);
4911 dtv = *dtvp = newdtv;
4914 /* Dynamically allocate module TLS if necessary */
4915 if (dtv[index + 1] == 0) {
4916 /* Signal safe, wlock will block out signals. */
4918 wlock_acquire(rtld_bind_lock, &lockstate);
4919 if (!dtv[index + 1])
4920 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4922 lock_release(rtld_bind_lock, &lockstate);
4924 return ((void *)(dtv[index + 1] + offset));
4928 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4933 /* Check dtv generation in case new modules have arrived */
4934 if (__predict_true(dtv[0] == tls_dtv_generation &&
4935 dtv[index + 1] != 0))
4936 return ((void *)(dtv[index + 1] + offset));
4937 return (tls_get_addr_slow(dtvp, index, offset, false));
4940 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4941 defined(__powerpc__) || defined(__riscv)
4944 * Return pointer to allocated TLS block
4947 get_tls_block_ptr(void *tcb, size_t tcbsize)
4949 size_t extra_size, post_size, pre_size, tls_block_size;
4950 size_t tls_init_align;
4952 tls_init_align = MAX(obj_main->tlsalign, 1);
4954 /* Compute fragments sizes. */
4955 extra_size = tcbsize - TLS_TCB_SIZE;
4956 post_size = calculate_tls_post_size(tls_init_align);
4957 tls_block_size = tcbsize + post_size;
4958 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4960 return ((char *)tcb - pre_size - extra_size);
4964 * Allocate Static TLS using the Variant I method.
4966 * For details on the layout, see lib/libc/gen/tls.c.
4968 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4969 * it is based on tls_last_offset, and TLS offsets here are really TCB
4970 * offsets, whereas libc's tls_static_space is just the executable's static
4974 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4978 Elf_Addr *dtv, **tcb;
4981 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4982 size_t tls_init_align, tls_init_offset;
4984 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4987 assert(tcbsize >= TLS_TCB_SIZE);
4988 maxalign = MAX(tcbalign, tls_static_max_align);
4989 tls_init_align = MAX(obj_main->tlsalign, 1);
4991 /* Compute fragmets sizes. */
4992 extra_size = tcbsize - TLS_TCB_SIZE;
4993 post_size = calculate_tls_post_size(tls_init_align);
4994 tls_block_size = tcbsize + post_size;
4995 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4996 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4998 /* Allocate whole TLS block */
4999 tls_block = malloc_aligned(tls_block_size, maxalign, 0);
5000 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
5002 if (oldtcb != NULL) {
5003 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
5005 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
5007 /* Adjust the DTV. */
5009 for (i = 0; i < dtv[1]; i++) {
5010 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
5011 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
5012 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
5016 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
5018 dtv[0] = tls_dtv_generation;
5019 dtv[1] = tls_max_index;
5021 for (obj = globallist_curr(objs); obj != NULL;
5022 obj = globallist_next(obj)) {
5023 if (obj->tlsoffset == 0)
5025 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
5026 addr = (Elf_Addr)tcb + obj->tlsoffset;
5027 if (tls_init_offset > 0)
5028 memset((void *)addr, 0, tls_init_offset);
5029 if (obj->tlsinitsize > 0) {
5030 memcpy((void *)(addr + tls_init_offset), obj->tlsinit,
5033 if (obj->tlssize > obj->tlsinitsize) {
5034 memset((void *)(addr + tls_init_offset + obj->tlsinitsize),
5035 0, obj->tlssize - obj->tlsinitsize - tls_init_offset);
5037 dtv[obj->tlsindex + 1] = addr;
5045 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
5048 Elf_Addr tlsstart, tlsend;
5050 size_t dtvsize, i, tls_init_align;
5052 assert(tcbsize >= TLS_TCB_SIZE);
5053 tls_init_align = MAX(obj_main->tlsalign, 1);
5055 /* Compute fragments sizes. */
5056 post_size = calculate_tls_post_size(tls_init_align);
5058 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
5059 tlsend = (Elf_Addr)tcb + tls_static_space;
5061 dtv = *(Elf_Addr **)tcb;
5063 for (i = 0; i < dtvsize; i++) {
5064 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
5065 free((void*)dtv[i+2]);
5069 free_aligned(get_tls_block_ptr(tcb, tcbsize));
5074 #if defined(__i386__) || defined(__amd64__)
5077 * Allocate Static TLS using the Variant II method.
5080 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
5083 size_t size, ralign;
5085 Elf_Addr *dtv, *olddtv;
5086 Elf_Addr segbase, oldsegbase, addr;
5090 if (tls_static_max_align > ralign)
5091 ralign = tls_static_max_align;
5092 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
5094 assert(tcbsize >= 2*sizeof(Elf_Addr));
5095 tls = malloc_aligned(size, ralign, 0 /* XXX */);
5096 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
5098 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign));
5099 ((Elf_Addr*)segbase)[0] = segbase;
5100 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
5102 dtv[0] = tls_dtv_generation;
5103 dtv[1] = tls_max_index;
5107 * Copy the static TLS block over whole.
5109 oldsegbase = (Elf_Addr) oldtls;
5110 memcpy((void *)(segbase - tls_static_space),
5111 (const void *)(oldsegbase - tls_static_space),
5115 * If any dynamic TLS blocks have been created tls_get_addr(),
5118 olddtv = ((Elf_Addr**)oldsegbase)[1];
5119 for (i = 0; i < olddtv[1]; i++) {
5120 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
5121 dtv[i+2] = olddtv[i+2];
5127 * We assume that this block was the one we created with
5128 * allocate_initial_tls().
5130 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
5132 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5133 if (obj->marker || obj->tlsoffset == 0)
5135 addr = segbase - obj->tlsoffset;
5136 memset((void*)(addr + obj->tlsinitsize),
5137 0, obj->tlssize - obj->tlsinitsize);
5139 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
5140 obj->static_tls_copied = true;
5142 dtv[obj->tlsindex + 1] = addr;
5146 return (void*) segbase;
5150 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
5153 size_t size, ralign;
5155 Elf_Addr tlsstart, tlsend;
5158 * Figure out the size of the initial TLS block so that we can
5159 * find stuff which ___tls_get_addr() allocated dynamically.
5162 if (tls_static_max_align > ralign)
5163 ralign = tls_static_max_align;
5164 size = roundup(tls_static_space, ralign);
5166 dtv = ((Elf_Addr**)tls)[1];
5168 tlsend = (Elf_Addr) tls;
5169 tlsstart = tlsend - size;
5170 for (i = 0; i < dtvsize; i++) {
5171 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
5172 free_aligned((void *)dtv[i + 2]);
5176 free_aligned((void *)tlsstart);
5183 * Allocate TLS block for module with given index.
5186 allocate_module_tls(int index)
5191 TAILQ_FOREACH(obj, &obj_list, next) {
5194 if (obj->tlsindex == index)
5198 _rtld_error("Can't find module with TLS index %d", index);
5202 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5203 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5204 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5209 allocate_tls_offset(Obj_Entry *obj)
5216 if (obj->tlssize == 0) {
5217 obj->tls_done = true;
5221 if (tls_last_offset == 0)
5222 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign,
5225 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5226 obj->tlssize, obj->tlsalign, obj->tlspoffset);
5229 * If we have already fixed the size of the static TLS block, we
5230 * must stay within that size. When allocating the static TLS, we
5231 * leave a small amount of space spare to be used for dynamically
5232 * loading modules which use static TLS.
5234 if (tls_static_space != 0) {
5235 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5237 } else if (obj->tlsalign > tls_static_max_align) {
5238 tls_static_max_align = obj->tlsalign;
5241 tls_last_offset = obj->tlsoffset = off;
5242 tls_last_size = obj->tlssize;
5243 obj->tls_done = true;
5249 free_tls_offset(Obj_Entry *obj)
5253 * If we were the last thing to allocate out of the static TLS
5254 * block, we give our space back to the 'allocator'. This is a
5255 * simplistic workaround to allow libGL.so.1 to be loaded and
5256 * unloaded multiple times.
5258 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5259 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5260 tls_last_offset -= obj->tlssize;
5266 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5269 RtldLockState lockstate;
5271 wlock_acquire(rtld_bind_lock, &lockstate);
5272 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5274 lock_release(rtld_bind_lock, &lockstate);
5279 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5281 RtldLockState lockstate;
5283 wlock_acquire(rtld_bind_lock, &lockstate);
5284 free_tls(tcb, tcbsize, tcbalign);
5285 lock_release(rtld_bind_lock, &lockstate);
5289 object_add_name(Obj_Entry *obj, const char *name)
5295 entry = malloc(sizeof(Name_Entry) + len);
5297 if (entry != NULL) {
5298 strcpy(entry->name, name);
5299 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5304 object_match_name(const Obj_Entry *obj, const char *name)
5308 STAILQ_FOREACH(entry, &obj->names, link) {
5309 if (strcmp(name, entry->name) == 0)
5316 locate_dependency(const Obj_Entry *obj, const char *name)
5318 const Objlist_Entry *entry;
5319 const Needed_Entry *needed;
5321 STAILQ_FOREACH(entry, &list_main, link) {
5322 if (object_match_name(entry->obj, name))
5326 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5327 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5328 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5330 * If there is DT_NEEDED for the name we are looking for,
5331 * we are all set. Note that object might not be found if
5332 * dependency was not loaded yet, so the function can
5333 * return NULL here. This is expected and handled
5334 * properly by the caller.
5336 return (needed->obj);
5339 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5345 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5346 const Elf_Vernaux *vna)
5348 const Elf_Verdef *vd;
5349 const char *vername;
5351 vername = refobj->strtab + vna->vna_name;
5352 vd = depobj->verdef;
5354 _rtld_error("%s: version %s required by %s not defined",
5355 depobj->path, vername, refobj->path);
5359 if (vd->vd_version != VER_DEF_CURRENT) {
5360 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5361 depobj->path, vd->vd_version);
5364 if (vna->vna_hash == vd->vd_hash) {
5365 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5366 ((const char *)vd + vd->vd_aux);
5367 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5370 if (vd->vd_next == 0)
5372 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5374 if (vna->vna_flags & VER_FLG_WEAK)
5376 _rtld_error("%s: version %s required by %s not found",
5377 depobj->path, vername, refobj->path);
5382 rtld_verify_object_versions(Obj_Entry *obj)
5384 const Elf_Verneed *vn;
5385 const Elf_Verdef *vd;
5386 const Elf_Verdaux *vda;
5387 const Elf_Vernaux *vna;
5388 const Obj_Entry *depobj;
5389 int maxvernum, vernum;
5391 if (obj->ver_checked)
5393 obj->ver_checked = true;
5397 * Walk over defined and required version records and figure out
5398 * max index used by any of them. Do very basic sanity checking
5402 while (vn != NULL) {
5403 if (vn->vn_version != VER_NEED_CURRENT) {
5404 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5405 obj->path, vn->vn_version);
5408 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5410 vernum = VER_NEED_IDX(vna->vna_other);
5411 if (vernum > maxvernum)
5413 if (vna->vna_next == 0)
5415 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5417 if (vn->vn_next == 0)
5419 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5423 while (vd != NULL) {
5424 if (vd->vd_version != VER_DEF_CURRENT) {
5425 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5426 obj->path, vd->vd_version);
5429 vernum = VER_DEF_IDX(vd->vd_ndx);
5430 if (vernum > maxvernum)
5432 if (vd->vd_next == 0)
5434 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5441 * Store version information in array indexable by version index.
5442 * Verify that object version requirements are satisfied along the
5445 obj->vernum = maxvernum + 1;
5446 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5449 while (vd != NULL) {
5450 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5451 vernum = VER_DEF_IDX(vd->vd_ndx);
5452 assert(vernum <= maxvernum);
5453 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5454 obj->vertab[vernum].hash = vd->vd_hash;
5455 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5456 obj->vertab[vernum].file = NULL;
5457 obj->vertab[vernum].flags = 0;
5459 if (vd->vd_next == 0)
5461 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5465 while (vn != NULL) {
5466 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5469 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5471 if (check_object_provided_version(obj, depobj, vna))
5473 vernum = VER_NEED_IDX(vna->vna_other);
5474 assert(vernum <= maxvernum);
5475 obj->vertab[vernum].hash = vna->vna_hash;
5476 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5477 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5478 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5479 VER_INFO_HIDDEN : 0;
5480 if (vna->vna_next == 0)
5482 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5484 if (vn->vn_next == 0)
5486 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5492 rtld_verify_versions(const Objlist *objlist)
5494 Objlist_Entry *entry;
5498 STAILQ_FOREACH(entry, objlist, link) {
5500 * Skip dummy objects or objects that have their version requirements
5503 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5505 if (rtld_verify_object_versions(entry->obj) == -1) {
5507 if (ld_tracing == NULL)
5511 if (rc == 0 || ld_tracing != NULL)
5512 rc = rtld_verify_object_versions(&obj_rtld);
5517 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5522 vernum = VER_NDX(obj->versyms[symnum]);
5523 if (vernum >= obj->vernum) {
5524 _rtld_error("%s: symbol %s has wrong verneed value %d",
5525 obj->path, obj->strtab + symnum, vernum);
5526 } else if (obj->vertab[vernum].hash != 0) {
5527 return &obj->vertab[vernum];
5534 _rtld_get_stack_prot(void)
5537 return (stack_prot);
5541 _rtld_is_dlopened(void *arg)
5544 RtldLockState lockstate;
5547 rlock_acquire(rtld_bind_lock, &lockstate);
5550 obj = obj_from_addr(arg);
5552 _rtld_error("No shared object contains address");
5553 lock_release(rtld_bind_lock, &lockstate);
5556 res = obj->dlopened ? 1 : 0;
5557 lock_release(rtld_bind_lock, &lockstate);
5562 obj_remap_relro(Obj_Entry *obj, int prot)
5565 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5567 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5568 obj->path, prot, rtld_strerror(errno));
5575 obj_disable_relro(Obj_Entry *obj)
5578 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5582 obj_enforce_relro(Obj_Entry *obj)
5585 return (obj_remap_relro(obj, PROT_READ));
5589 map_stacks_exec(RtldLockState *lockstate)
5591 void (*thr_map_stacks_exec)(void);
5593 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5595 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5596 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5597 if (thr_map_stacks_exec != NULL) {
5598 stack_prot |= PROT_EXEC;
5599 thr_map_stacks_exec();
5604 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5608 void (*distrib)(size_t, void *, size_t, size_t);
5610 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5611 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5612 if (distrib == NULL)
5614 STAILQ_FOREACH(elm, list, link) {
5616 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5618 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5620 obj->static_tls_copied = true;
5625 symlook_init(SymLook *dst, const char *name)
5628 bzero(dst, sizeof(*dst));
5630 dst->hash = elf_hash(name);
5631 dst->hash_gnu = gnu_hash(name);
5635 symlook_init_from_req(SymLook *dst, const SymLook *src)
5638 dst->name = src->name;
5639 dst->hash = src->hash;
5640 dst->hash_gnu = src->hash_gnu;
5641 dst->ventry = src->ventry;
5642 dst->flags = src->flags;
5643 dst->defobj_out = NULL;
5644 dst->sym_out = NULL;
5645 dst->lockstate = src->lockstate;
5649 open_binary_fd(const char *argv0, bool search_in_path,
5650 const char **binpath_res)
5652 char *binpath, *pathenv, *pe, *res1;
5658 if (search_in_path && strchr(argv0, '/') == NULL) {
5659 binpath = xmalloc(PATH_MAX);
5660 pathenv = getenv("PATH");
5661 if (pathenv == NULL) {
5662 _rtld_error("-p and no PATH environment variable");
5665 pathenv = strdup(pathenv);
5666 if (pathenv == NULL) {
5667 _rtld_error("Cannot allocate memory");
5672 while ((pe = strsep(&pathenv, ":")) != NULL) {
5673 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
5675 if (binpath[0] != '\0' &&
5676 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
5678 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
5680 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5681 if (fd != -1 || errno != ENOENT) {
5688 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5693 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5696 if (res != NULL && res[0] != '/') {
5697 res1 = xmalloc(PATH_MAX);
5698 if (realpath(res, res1) != NULL) {
5700 free(__DECONST(char *, res));
5711 * Parse a set of command-line arguments.
5714 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
5720 int arglen, fd, i, j, mib[2];
5722 bool seen_b, seen_f;
5724 dbg("Parsing command-line arguments");
5727 seen_b = seen_f = false;
5729 for (i = 1; i < argc; i++ ) {
5731 dbg("argv[%d]: '%s'", i, arg);
5734 * rtld arguments end with an explicit "--" or with the first
5735 * non-prefixed argument.
5737 if (strcmp(arg, "--") == 0) {
5745 * All other arguments are single-character options that can
5746 * be combined, so we need to search through `arg` for them.
5748 arglen = strlen(arg);
5749 for (j = 1; j < arglen; j++) {
5752 print_usage(argv[0]);
5754 } else if (opt == 'b') {
5756 _rtld_error("Both -b and -f specified");
5763 } else if (opt == 'f') {
5765 _rtld_error("Both -b and -f specified");
5770 * -f XX can be used to specify a
5771 * descriptor for the binary named at
5772 * the command line (i.e., the later
5773 * argument will specify the process
5774 * name but the descriptor is what
5775 * will actually be executed).
5777 * -f must be the last option in, e.g., -abcf.
5779 if (j != arglen - 1) {
5780 _rtld_error("Invalid options: %s", arg);
5784 fd = parse_integer(argv[i]);
5787 "Invalid file descriptor: '%s'",
5794 } else if (opt == 'p') {
5796 } else if (opt == 'u') {
5798 } else if (opt == 'v') {
5801 mib[1] = HW_MACHINE;
5802 sz = sizeof(machine);
5803 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
5805 "FreeBSD ld-elf.so.1 %s\n"
5806 "FreeBSD_version %d\n"
5807 "Default lib path %s\n"
5812 __FreeBSD_version, ld_standard_library_path,
5813 ld_env_prefix, ld_elf_hints_default,
5814 ld_path_libmap_conf);
5817 _rtld_error("Invalid argument: '%s'", arg);
5818 print_usage(argv[0]);
5830 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5833 parse_integer(const char *str)
5835 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5842 for (c = *str; c != '\0'; c = *++str) {
5843 if (c < '0' || c > '9')
5850 /* Make sure we actually parsed something. */
5857 print_usage(const char *argv0)
5861 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n"
5864 " -h Display this help message\n"
5865 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
5866 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5867 " -p Search in PATH for named binary\n"
5868 " -u Ignore LD_ environment variables\n"
5869 " -v Display identification information\n"
5870 " -- End of RTLD options\n"
5871 " <binary> Name of process to execute\n"
5872 " <args> Arguments to the executed process\n", argv0);
5876 * Overrides for libc_pic-provided functions.
5880 __getosreldate(void)
5890 oid[1] = KERN_OSRELDATE;
5892 len = sizeof(osrel);
5893 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5894 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5899 rtld_strerror(int errnum)
5902 if (errnum < 0 || errnum >= sys_nerr)
5903 return ("Unknown error");
5904 return (sys_errlist[errnum]);
5909 malloc(size_t nbytes)
5912 return (__crt_malloc(nbytes));
5916 calloc(size_t num, size_t size)
5919 return (__crt_calloc(num, size));
5930 realloc(void *cp, size_t nbytes)
5933 return (__crt_realloc(cp, nbytes));
5936 extern int _rtld_version__FreeBSD_version __exported;
5937 int _rtld_version__FreeBSD_version = __FreeBSD_version;
5939 extern char _rtld_version_laddr_offset __exported;
5940 char _rtld_version_laddr_offset;
5942 extern char _rtld_version_dlpi_tls_data __exported;
5943 char _rtld_version_dlpi_tls_data;