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);
86 * Function declarations.
88 static const char *basename(const char *);
89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
90 const Elf_Dyn **, const Elf_Dyn **);
91 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
93 static bool digest_dynamic(Obj_Entry *, int);
94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
95 static void distribute_static_tls(Objlist *, RtldLockState *);
96 static Obj_Entry *dlcheck(void *);
97 static int dlclose_locked(void *, RtldLockState *);
98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
99 int lo_flags, int mode, RtldLockState *lockstate);
100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
102 static bool donelist_check(DoneList *, const Obj_Entry *);
103 static void errmsg_restore(char *);
104 static char *errmsg_save(void);
105 static void *fill_search_info(const char *, size_t, void *);
106 static char *find_library(const char *, const Obj_Entry *, int *);
107 static const char *gethints(bool);
108 static void hold_object(Obj_Entry *);
109 static void unhold_object(Obj_Entry *);
110 static void init_dag(Obj_Entry *);
111 static void init_marker(Obj_Entry *);
112 static void init_pagesizes(Elf_Auxinfo **aux_info);
113 static void init_rtld(caddr_t, Elf_Auxinfo **);
114 static void initlist_add_neededs(Needed_Entry *, Objlist *);
115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
117 static void linkmap_add(Obj_Entry *);
118 static void linkmap_delete(Obj_Entry *);
119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
120 static void unload_filtees(Obj_Entry *, RtldLockState *);
121 static int load_needed_objects(Obj_Entry *, int);
122 static int load_preload_objects(void);
123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
124 static void map_stacks_exec(RtldLockState *);
125 static int obj_disable_relro(Obj_Entry *);
126 static int obj_enforce_relro(Obj_Entry *);
127 static Obj_Entry *obj_from_addr(const void *);
128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
129 static void objlist_call_init(Objlist *, RtldLockState *);
130 static void objlist_clear(Objlist *);
131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
132 static void objlist_init(Objlist *);
133 static void objlist_push_head(Objlist *, Obj_Entry *);
134 static void objlist_push_tail(Objlist *, Obj_Entry *);
135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
136 static void objlist_remove(Objlist *, Obj_Entry *);
137 static int open_binary_fd(const char *argv0, bool search_in_path,
138 const char **binpath_res);
139 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
141 static int parse_integer(const char *);
142 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
143 static void print_usage(const char *argv0);
144 static void release_object(Obj_Entry *);
145 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
146 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
147 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
148 int flags, RtldLockState *lockstate);
149 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
151 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
152 static int rtld_dirname(const char *, char *);
153 static int rtld_dirname_abs(const char *, char *);
154 static void *rtld_dlopen(const char *name, int fd, int mode);
155 static void rtld_exit(void);
156 static void rtld_nop_exit(void);
157 static char *search_library_path(const char *, const char *, const char *,
159 static char *search_library_pathfds(const char *, const char *, int *);
160 static const void **get_program_var_addr(const char *, RtldLockState *);
161 static void set_program_var(const char *, const void *);
162 static int symlook_default(SymLook *, const Obj_Entry *refobj);
163 static int symlook_global(SymLook *, DoneList *);
164 static void symlook_init_from_req(SymLook *, const SymLook *);
165 static int symlook_list(SymLook *, const Objlist *, DoneList *);
166 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
167 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
168 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
169 static void trace_loaded_objects(Obj_Entry *);
170 static void unlink_object(Obj_Entry *);
171 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
172 static void unref_dag(Obj_Entry *);
173 static void ref_dag(Obj_Entry *);
174 static char *origin_subst_one(Obj_Entry *, char *, const char *,
176 static char *origin_subst(Obj_Entry *, const char *);
177 static bool obj_resolve_origin(Obj_Entry *obj);
178 static void preinit_main(void);
179 static int rtld_verify_versions(const Objlist *);
180 static int rtld_verify_object_versions(Obj_Entry *);
181 static void object_add_name(Obj_Entry *, const char *);
182 static int object_match_name(const Obj_Entry *, const char *);
183 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
184 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
185 struct dl_phdr_info *phdr_info);
186 static uint32_t gnu_hash(const char *);
187 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
188 const unsigned long);
190 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
191 void _r_debug_postinit(struct link_map *) __noinline __exported;
193 int __sys_openat(int, const char *, int, ...);
198 static char *error_message; /* Message for dlerror(), or NULL */
199 struct r_debug r_debug __exported; /* for GDB; */
200 static bool libmap_disable; /* Disable libmap */
201 static bool ld_loadfltr; /* Immediate filters processing */
202 static char *libmap_override; /* Maps to use in addition to libmap.conf */
203 static bool trust; /* False for setuid and setgid programs */
204 static bool dangerous_ld_env; /* True if environment variables have been
205 used to affect the libraries loaded */
206 bool ld_bind_not; /* Disable PLT update */
207 static char *ld_bind_now; /* Environment variable for immediate binding */
208 static char *ld_debug; /* Environment variable for debugging */
209 static char *ld_library_path; /* Environment variable for search path */
210 static char *ld_library_dirs; /* Environment variable for library descriptors */
211 static char *ld_preload; /* Environment variable for libraries to
213 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
214 static const char *ld_tracing; /* Called from ldd to print libs */
215 static char *ld_utrace; /* Use utrace() to log events. */
216 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
217 static Obj_Entry *obj_main; /* The main program shared object */
218 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
219 static unsigned int obj_count; /* Number of objects in obj_list */
220 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
222 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
223 STAILQ_HEAD_INITIALIZER(list_global);
224 static Objlist list_main = /* Objects loaded at program startup */
225 STAILQ_HEAD_INITIALIZER(list_main);
226 static Objlist list_fini = /* Objects needing fini() calls */
227 STAILQ_HEAD_INITIALIZER(list_fini);
229 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
231 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
233 extern Elf_Dyn _DYNAMIC;
234 #pragma weak _DYNAMIC
236 int dlclose(void *) __exported;
237 char *dlerror(void) __exported;
238 void *dlopen(const char *, int) __exported;
239 void *fdlopen(int, int) __exported;
240 void *dlsym(void *, const char *) __exported;
241 dlfunc_t dlfunc(void *, const char *) __exported;
242 void *dlvsym(void *, const char *, const char *) __exported;
243 int dladdr(const void *, Dl_info *) __exported;
244 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
245 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
246 int dlinfo(void *, int , void *) __exported;
247 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
248 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
249 int _rtld_get_stack_prot(void) __exported;
250 int _rtld_is_dlopened(void *) __exported;
251 void _rtld_error(const char *, ...) __exported;
253 /* Only here to fix -Wmissing-prototypes warnings */
254 int __getosreldate(void);
255 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
256 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
260 static int osreldate;
263 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
264 static int max_stack_flags;
267 * Global declarations normally provided by crt1. The dynamic linker is
268 * not built with crt1, so we have to provide them ourselves.
274 * Used to pass argc, argv to init functions.
280 * Globals to control TLS allocation.
282 size_t tls_last_offset; /* Static TLS offset of last module */
283 size_t tls_last_size; /* Static TLS size of last module */
284 size_t tls_static_space; /* Static TLS space allocated */
285 static size_t tls_static_max_align;
286 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
287 int tls_max_index = 1; /* Largest module index allocated */
289 static bool ld_library_path_rpath = false;
290 bool ld_fast_sigblock = false;
293 * Globals for path names, and such
295 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
296 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
297 const char *ld_path_rtld = _PATH_RTLD;
298 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
299 const char *ld_env_prefix = LD_;
301 static void (*rtld_exit_ptr)(void);
304 * Fill in a DoneList with an allocation large enough to hold all of
305 * the currently-loaded objects. Keep this as a macro since it calls
306 * alloca and we want that to occur within the scope of the caller.
308 #define donelist_init(dlp) \
309 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
310 assert((dlp)->objs != NULL), \
311 (dlp)->num_alloc = obj_count, \
314 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
315 if (ld_utrace != NULL) \
316 ld_utrace_log(e, h, mb, ms, r, n); \
320 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
321 int refcnt, const char *name)
323 struct utrace_rtld ut;
324 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
326 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
329 ut.mapbase = mapbase;
330 ut.mapsize = mapsize;
332 bzero(ut.name, sizeof(ut.name));
334 strlcpy(ut.name, name, sizeof(ut.name));
335 utrace(&ut, sizeof(ut));
338 #ifdef RTLD_VARIANT_ENV_NAMES
340 * construct the env variable based on the type of binary that's
343 static inline const char *
346 static char buffer[128];
348 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
349 strlcat(buffer, var, sizeof(buffer));
357 * Main entry point for dynamic linking. The first argument is the
358 * stack pointer. The stack is expected to be laid out as described
359 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
360 * Specifically, the stack pointer points to a word containing
361 * ARGC. Following that in the stack is a null-terminated sequence
362 * of pointers to argument strings. Then comes a null-terminated
363 * sequence of pointers to environment strings. Finally, there is a
364 * sequence of "auxiliary vector" entries.
366 * The second argument points to a place to store the dynamic linker's
367 * exit procedure pointer and the third to a place to store the main
370 * The return value is the main program's entry point.
373 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
375 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
376 Objlist_Entry *entry;
377 Obj_Entry *last_interposer, *obj, *preload_tail;
378 const Elf_Phdr *phdr;
380 RtldLockState lockstate;
383 char **argv, **env, **envp, *kexecpath, *library_path_rpath;
384 const char *argv0, *binpath;
386 char buf[MAXPATHLEN];
387 int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc;
390 int old_auxv_format = 1;
392 bool dir_enable, direct_exec, explicit_fd, search_in_path;
395 * On entry, the dynamic linker itself has not been relocated yet.
396 * Be very careful not to reference any global data until after
397 * init_rtld has returned. It is OK to reference file-scope statics
398 * and string constants, and to call static and global functions.
401 /* Find the auxiliary vector on the stack. */
405 sp += argc + 1; /* Skip over arguments and NULL terminator */
407 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
409 aux = (Elf_Auxinfo *) sp;
411 /* Digest the auxiliary vector. */
412 for (i = 0; i < AT_COUNT; i++)
414 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
415 if (auxp->a_type < AT_COUNT)
416 aux_info[auxp->a_type] = auxp;
418 if (auxp->a_type == 23) /* AT_STACKPROT */
424 if (old_auxv_format) {
425 /* Remap from old-style auxv numbers. */
426 aux_info[23] = aux_info[21]; /* AT_STACKPROT */
427 aux_info[21] = aux_info[19]; /* AT_PAGESIZESLEN */
428 aux_info[19] = aux_info[17]; /* AT_NCPUS */
429 aux_info[17] = aux_info[15]; /* AT_CANARYLEN */
430 aux_info[15] = aux_info[13]; /* AT_EXECPATH */
431 aux_info[13] = NULL; /* AT_GID */
433 aux_info[20] = aux_info[18]; /* AT_PAGESIZES */
434 aux_info[18] = aux_info[16]; /* AT_OSRELDATE */
435 aux_info[16] = aux_info[14]; /* AT_CANARY */
436 aux_info[14] = NULL; /* AT_EGID */
440 /* Initialize and relocate ourselves. */
441 assert(aux_info[AT_BASE] != NULL);
442 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
444 __progname = obj_rtld.path;
445 argv0 = argv[0] != NULL ? argv[0] : "(null)";
450 if (aux_info[AT_BSDFLAGS] != NULL &&
451 (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0)
452 ld_fast_sigblock = true;
454 trust = !issetugid();
457 md_abi_variant_hook(aux_info);
460 if (aux_info[AT_EXECFD] != NULL) {
461 fd = aux_info[AT_EXECFD]->a_un.a_val;
463 assert(aux_info[AT_PHDR] != NULL);
464 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
465 if (phdr == obj_rtld.phdr) {
467 _rtld_error("Tainted process refusing to run binary %s",
473 dbg("opening main program in direct exec mode");
475 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0);
476 explicit_fd = (fd != -1);
479 fd = open_binary_fd(argv0, search_in_path, &binpath);
480 if (fstat(fd, &st) == -1) {
481 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
482 explicit_fd ? "user-provided descriptor" : argv0,
483 rtld_strerror(errno));
488 * Rough emulation of the permission checks done by
489 * execve(2), only Unix DACs are checked, ACLs are
490 * ignored. Preserve the semantic of disabling owner
491 * to execute if owner x bit is cleared, even if
492 * others x bit is enabled.
493 * mmap(2) does not allow to mmap with PROT_EXEC if
494 * binary' file comes from noexec mount. We cannot
495 * set a text reference on the binary.
498 if (st.st_uid == geteuid()) {
499 if ((st.st_mode & S_IXUSR) != 0)
501 } else if (st.st_gid == getegid()) {
502 if ((st.st_mode & S_IXGRP) != 0)
504 } else if ((st.st_mode & S_IXOTH) != 0) {
508 _rtld_error("No execute permission for binary %s",
514 * For direct exec mode, argv[0] is the interpreter
515 * name, we must remove it and shift arguments left
516 * before invoking binary main. Since stack layout
517 * places environment pointers and aux vectors right
518 * after the terminating NULL, we must shift
519 * environment and aux as well.
521 main_argc = argc - rtld_argc;
522 for (i = 0; i <= main_argc; i++)
523 argv[i] = argv[i + rtld_argc];
525 environ = env = envp = argv + main_argc + 1;
526 dbg("move env from %p to %p", envp + rtld_argc, envp);
528 *envp = *(envp + rtld_argc);
529 } while (*envp++ != NULL);
530 aux = auxp = (Elf_Auxinfo *)envp;
531 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
532 dbg("move aux from %p to %p", auxpf, aux);
533 /* XXXKIB insert place for AT_EXECPATH if not present */
534 for (;; auxp++, auxpf++) {
536 if (auxp->a_type == AT_NULL)
539 /* Since the auxiliary vector has moved, redigest it. */
540 for (i = 0; i < AT_COUNT; i++)
542 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
543 if (auxp->a_type < AT_COUNT)
544 aux_info[auxp->a_type] = auxp;
547 /* Point AT_EXECPATH auxv and aux_info to the binary path. */
548 if (binpath == NULL) {
549 aux_info[AT_EXECPATH] = NULL;
551 if (aux_info[AT_EXECPATH] == NULL) {
552 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo));
553 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH;
555 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *,
559 _rtld_error("No binary");
565 ld_bind_now = getenv(_LD("BIND_NOW"));
568 * If the process is tainted, then we un-set the dangerous environment
569 * variables. The process will be marked as tainted until setuid(2)
570 * is called. If any child process calls setuid(2) we do not want any
571 * future processes to honor the potentially un-safe variables.
574 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
575 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
576 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
577 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
578 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
579 _rtld_error("environment corrupt; aborting");
583 ld_debug = getenv(_LD("DEBUG"));
584 if (ld_bind_now == NULL)
585 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
586 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
587 libmap_override = getenv(_LD("LIBMAP"));
588 ld_library_path = getenv(_LD("LIBRARY_PATH"));
589 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
590 ld_preload = getenv(_LD("PRELOAD"));
591 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
592 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
593 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
594 if (library_path_rpath != NULL) {
595 if (library_path_rpath[0] == 'y' ||
596 library_path_rpath[0] == 'Y' ||
597 library_path_rpath[0] == '1')
598 ld_library_path_rpath = true;
600 ld_library_path_rpath = false;
602 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
603 (ld_library_path != NULL) || (ld_preload != NULL) ||
604 (ld_elf_hints_path != NULL) || ld_loadfltr;
605 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
606 ld_utrace = getenv(_LD("UTRACE"));
608 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
609 ld_elf_hints_path = ld_elf_hints_default;
611 if (ld_debug != NULL && *ld_debug != '\0')
613 dbg("%s is initialized, base address = %p", __progname,
614 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
615 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
616 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
618 dbg("initializing thread locks");
622 * Load the main program, or process its program header if it is
625 if (fd != -1) { /* Load the main program. */
626 dbg("loading main program");
627 obj_main = map_object(fd, argv0, NULL);
629 if (obj_main == NULL)
631 max_stack_flags = obj_main->stack_flags;
632 } else { /* Main program already loaded. */
633 dbg("processing main program's program header");
634 assert(aux_info[AT_PHDR] != NULL);
635 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
636 assert(aux_info[AT_PHNUM] != NULL);
637 phnum = aux_info[AT_PHNUM]->a_un.a_val;
638 assert(aux_info[AT_PHENT] != NULL);
639 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
640 assert(aux_info[AT_ENTRY] != NULL);
641 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
642 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
646 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
647 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
648 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
649 if (kexecpath[0] == '/')
650 obj_main->path = kexecpath;
651 else if (getcwd(buf, sizeof(buf)) == NULL ||
652 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
653 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
654 obj_main->path = xstrdup(argv0);
656 obj_main->path = xstrdup(buf);
658 dbg("No AT_EXECPATH or direct exec");
659 obj_main->path = xstrdup(argv0);
661 dbg("obj_main path %s", obj_main->path);
662 obj_main->mainprog = true;
664 if (aux_info[AT_STACKPROT] != NULL &&
665 aux_info[AT_STACKPROT]->a_un.a_val != 0)
666 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
670 * Get the actual dynamic linker pathname from the executable if
671 * possible. (It should always be possible.) That ensures that
672 * gdb will find the right dynamic linker even if a non-standard
675 if (obj_main->interp != NULL &&
676 strcmp(obj_main->interp, obj_rtld.path) != 0) {
678 obj_rtld.path = xstrdup(obj_main->interp);
679 __progname = obj_rtld.path;
683 if (!digest_dynamic(obj_main, 0))
685 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
686 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
687 obj_main->dynsymcount);
689 linkmap_add(obj_main);
690 linkmap_add(&obj_rtld);
692 /* Link the main program into the list of objects. */
693 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
697 /* Initialize a fake symbol for resolving undefined weak references. */
698 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
699 sym_zero.st_shndx = SHN_UNDEF;
700 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
703 libmap_disable = (bool)lm_init(libmap_override);
705 dbg("loading LD_PRELOAD libraries");
706 if (load_preload_objects() == -1)
708 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
710 dbg("loading needed objects");
711 if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE :
715 /* Make a list of all objects loaded at startup. */
716 last_interposer = obj_main;
717 TAILQ_FOREACH(obj, &obj_list, next) {
720 if (obj->z_interpose && obj != obj_main) {
721 objlist_put_after(&list_main, last_interposer, obj);
722 last_interposer = obj;
724 objlist_push_tail(&list_main, obj);
729 dbg("checking for required versions");
730 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
733 if (ld_tracing) { /* We're done */
734 trace_loaded_objects(obj_main);
738 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
739 dump_relocations(obj_main);
744 * Processing tls relocations requires having the tls offsets
745 * initialized. Prepare offsets before starting initial
746 * relocation processing.
748 dbg("initializing initial thread local storage offsets");
749 STAILQ_FOREACH(entry, &list_main, link) {
751 * Allocate all the initial objects out of the static TLS
752 * block even if they didn't ask for it.
754 allocate_tls_offset(entry->obj);
757 if (relocate_objects(obj_main,
758 ld_bind_now != NULL && *ld_bind_now != '\0',
759 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
762 dbg("doing copy relocations");
763 if (do_copy_relocations(obj_main) == -1)
766 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
767 dump_relocations(obj_main);
774 * Setup TLS for main thread. This must be done after the
775 * relocations are processed, since tls initialization section
776 * might be the subject for relocations.
778 dbg("initializing initial thread local storage");
779 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
781 dbg("initializing key program variables");
782 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
783 set_program_var("environ", env);
784 set_program_var("__elf_aux_vector", aux);
786 /* Make a list of init functions to call. */
787 objlist_init(&initlist);
788 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
789 preload_tail, &initlist);
791 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
793 map_stacks_exec(NULL);
795 if (!obj_main->crt_no_init) {
797 * Make sure we don't call the main program's init and fini
798 * functions for binaries linked with old crt1 which calls
801 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
802 obj_main->preinit_array = obj_main->init_array =
803 obj_main->fini_array = (Elf_Addr)NULL;
807 /* Set osrel for direct-execed binary */
810 mib[2] = KERN_PROC_OSREL;
812 osrel = obj_main->osrel;
813 sz = sizeof(old_osrel);
814 dbg("setting osrel to %d", osrel);
815 (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel));
818 wlock_acquire(rtld_bind_lock, &lockstate);
820 dbg("resolving ifuncs");
821 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
822 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
825 rtld_exit_ptr = rtld_exit;
826 if (obj_main->crt_no_init)
828 objlist_call_init(&initlist, &lockstate);
829 _r_debug_postinit(&obj_main->linkmap);
830 objlist_clear(&initlist);
831 dbg("loading filtees");
832 TAILQ_FOREACH(obj, &obj_list, next) {
835 if (ld_loadfltr || obj->z_loadfltr)
836 load_filtees(obj, 0, &lockstate);
839 dbg("enforcing main obj relro");
840 if (obj_enforce_relro(obj_main) == -1)
843 lock_release(rtld_bind_lock, &lockstate);
845 dbg("transferring control to program entry point = %p", obj_main->entry);
847 /* Return the exit procedure and the program entry point. */
848 *exit_proc = rtld_exit_ptr;
850 return (func_ptr_type) obj_main->entry;
854 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
859 ptr = (void *)make_function_pointer(def, obj);
860 target = call_ifunc_resolver(ptr);
861 return ((void *)target);
865 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
866 * Changes to this function should be applied there as well.
869 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
873 const Obj_Entry *defobj;
876 RtldLockState lockstate;
878 rlock_acquire(rtld_bind_lock, &lockstate);
879 if (sigsetjmp(lockstate.env, 0) != 0)
880 lock_upgrade(rtld_bind_lock, &lockstate);
882 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
884 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
886 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
887 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
891 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
892 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
894 target = (Elf_Addr)(defobj->relocbase + def->st_value);
896 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
897 defobj->strtab + def->st_name,
898 obj->path == NULL ? NULL : basename(obj->path),
900 defobj->path == NULL ? NULL : basename(defobj->path));
903 * Write the new contents for the jmpslot. Note that depending on
904 * architecture, the value which we need to return back to the
905 * lazy binding trampoline may or may not be the target
906 * address. The value returned from reloc_jmpslot() is the value
907 * that the trampoline needs.
909 target = reloc_jmpslot(where, target, defobj, obj, rel);
910 lock_release(rtld_bind_lock, &lockstate);
915 * Error reporting function. Use it like printf. If formats the message
916 * into a buffer, and sets things up so that the next call to dlerror()
917 * will return the message.
920 _rtld_error(const char *fmt, ...)
922 static char buf[512];
926 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
929 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
933 * Return a dynamically-allocated copy of the current error message, if any.
938 return error_message == NULL ? NULL : xstrdup(error_message);
942 * Restore the current error message from a copy which was previously saved
943 * by errmsg_save(). The copy is freed.
946 errmsg_restore(char *saved_msg)
948 if (saved_msg == NULL)
949 error_message = NULL;
951 _rtld_error("%s", saved_msg);
957 basename(const char *name)
959 const char *p = strrchr(name, '/');
960 return p != NULL ? p + 1 : name;
963 static struct utsname uts;
966 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
967 const char *subst, bool may_free)
969 char *p, *p1, *res, *resp;
970 int subst_len, kw_len, subst_count, old_len, new_len;
975 * First, count the number of the keyword occurrences, to
976 * preallocate the final string.
978 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
985 * If the keyword is not found, just return.
987 * Return non-substituted string if resolution failed. We
988 * cannot do anything more reasonable, the failure mode of the
989 * caller is unresolved library anyway.
991 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
992 return (may_free ? real : xstrdup(real));
994 subst = obj->origin_path;
997 * There is indeed something to substitute. Calculate the
998 * length of the resulting string, and allocate it.
1000 subst_len = strlen(subst);
1001 old_len = strlen(real);
1002 new_len = old_len + (subst_len - kw_len) * subst_count;
1003 res = xmalloc(new_len + 1);
1006 * Now, execute the substitution loop.
1008 for (p = real, resp = res, *resp = '\0';;) {
1011 /* Copy the prefix before keyword. */
1012 memcpy(resp, p, p1 - p);
1014 /* Keyword replacement. */
1015 memcpy(resp, subst, subst_len);
1023 /* Copy to the end of string and finish. */
1031 origin_subst(Obj_Entry *obj, const char *real)
1033 char *res1, *res2, *res3, *res4;
1035 if (obj == NULL || !trust)
1036 return (xstrdup(real));
1037 if (uts.sysname[0] == '\0') {
1038 if (uname(&uts) != 0) {
1039 _rtld_error("utsname failed: %d", errno);
1043 /* __DECONST is safe here since without may_free real is unchanged */
1044 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL,
1046 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
1047 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
1048 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
1055 const char *msg = dlerror();
1058 msg = "Fatal error";
1059 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1060 rtld_fdputstr(STDERR_FILENO, msg);
1061 rtld_fdputchar(STDERR_FILENO, '\n');
1066 * Process a shared object's DYNAMIC section, and save the important
1067 * information in its Obj_Entry structure.
1070 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1071 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1073 const Elf_Dyn *dynp;
1074 Needed_Entry **needed_tail = &obj->needed;
1075 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1076 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1077 const Elf_Hashelt *hashtab;
1078 const Elf32_Word *hashval;
1079 Elf32_Word bkt, nmaskwords;
1081 int plttype = DT_REL;
1085 *dyn_runpath = NULL;
1087 obj->bind_now = false;
1088 dynp = obj->dynamic;
1091 for (; dynp->d_tag != DT_NULL; dynp++) {
1092 switch (dynp->d_tag) {
1095 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1099 obj->relsize = dynp->d_un.d_val;
1103 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1107 obj->pltrel = (const Elf_Rel *)
1108 (obj->relocbase + dynp->d_un.d_ptr);
1112 obj->pltrelsize = dynp->d_un.d_val;
1116 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1120 obj->relasize = dynp->d_un.d_val;
1124 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1128 plttype = dynp->d_un.d_val;
1129 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1133 obj->symtab = (const Elf_Sym *)
1134 (obj->relocbase + dynp->d_un.d_ptr);
1138 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1142 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1146 obj->strsize = dynp->d_un.d_val;
1150 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1155 obj->verneednum = dynp->d_un.d_val;
1159 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1164 obj->verdefnum = dynp->d_un.d_val;
1168 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1174 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1176 obj->nbuckets = hashtab[0];
1177 obj->nchains = hashtab[1];
1178 obj->buckets = hashtab + 2;
1179 obj->chains = obj->buckets + obj->nbuckets;
1180 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1181 obj->buckets != NULL;
1187 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1189 obj->nbuckets_gnu = hashtab[0];
1190 obj->symndx_gnu = hashtab[1];
1191 nmaskwords = hashtab[2];
1192 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1193 obj->maskwords_bm_gnu = nmaskwords - 1;
1194 obj->shift2_gnu = hashtab[3];
1195 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1196 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1197 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1199 /* Number of bitmask words is required to be power of 2 */
1200 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1201 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1207 Needed_Entry *nep = NEW(Needed_Entry);
1208 nep->name = dynp->d_un.d_val;
1213 needed_tail = &nep->next;
1219 Needed_Entry *nep = NEW(Needed_Entry);
1220 nep->name = dynp->d_un.d_val;
1224 *needed_filtees_tail = nep;
1225 needed_filtees_tail = &nep->next;
1227 if (obj->linkmap.l_refname == NULL)
1228 obj->linkmap.l_refname = (char *)dynp->d_un.d_val;
1234 Needed_Entry *nep = NEW(Needed_Entry);
1235 nep->name = dynp->d_un.d_val;
1239 *needed_aux_filtees_tail = nep;
1240 needed_aux_filtees_tail = &nep->next;
1245 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1249 obj->textrel = true;
1253 obj->symbolic = true;
1258 * We have to wait until later to process this, because we
1259 * might not have gotten the address of the string table yet.
1269 *dyn_runpath = dynp;
1273 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1276 case DT_PREINIT_ARRAY:
1277 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1280 case DT_PREINIT_ARRAYSZ:
1281 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1285 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1288 case DT_INIT_ARRAYSZ:
1289 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1293 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1297 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1300 case DT_FINI_ARRAYSZ:
1301 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1305 * Don't process DT_DEBUG on MIPS as the dynamic section
1306 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1312 dbg("Filling in DT_DEBUG entry");
1313 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1318 if (dynp->d_un.d_val & DF_ORIGIN)
1319 obj->z_origin = true;
1320 if (dynp->d_un.d_val & DF_SYMBOLIC)
1321 obj->symbolic = true;
1322 if (dynp->d_un.d_val & DF_TEXTREL)
1323 obj->textrel = true;
1324 if (dynp->d_un.d_val & DF_BIND_NOW)
1325 obj->bind_now = true;
1326 if (dynp->d_un.d_val & DF_STATIC_TLS)
1327 obj->static_tls = true;
1330 case DT_MIPS_LOCAL_GOTNO:
1331 obj->local_gotno = dynp->d_un.d_val;
1334 case DT_MIPS_SYMTABNO:
1335 obj->symtabno = dynp->d_un.d_val;
1338 case DT_MIPS_GOTSYM:
1339 obj->gotsym = dynp->d_un.d_val;
1342 case DT_MIPS_RLD_MAP:
1343 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1346 case DT_MIPS_RLD_MAP_REL:
1347 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map
1348 // section relative to the address of the tag itself.
1349 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) =
1350 (Elf_Addr) &r_debug;
1353 case DT_MIPS_PLTGOT:
1354 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase +
1361 #ifdef __powerpc64__
1362 case DT_PPC64_GLINK:
1363 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1367 obj->gotptr = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1373 if (dynp->d_un.d_val & DF_1_NOOPEN)
1374 obj->z_noopen = true;
1375 if (dynp->d_un.d_val & DF_1_ORIGIN)
1376 obj->z_origin = true;
1377 if (dynp->d_un.d_val & DF_1_GLOBAL)
1378 obj->z_global = true;
1379 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1380 obj->bind_now = true;
1381 if (dynp->d_un.d_val & DF_1_NODELETE)
1382 obj->z_nodelete = true;
1383 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1384 obj->z_loadfltr = true;
1385 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1386 obj->z_interpose = true;
1387 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1388 obj->z_nodeflib = true;
1389 if (dynp->d_un.d_val & DF_1_PIE)
1395 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1402 obj->traced = false;
1404 if (plttype == DT_RELA) {
1405 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1407 obj->pltrelasize = obj->pltrelsize;
1408 obj->pltrelsize = 0;
1411 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1412 if (obj->valid_hash_sysv)
1413 obj->dynsymcount = obj->nchains;
1414 else if (obj->valid_hash_gnu) {
1415 obj->dynsymcount = 0;
1416 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1417 if (obj->buckets_gnu[bkt] == 0)
1419 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1422 while ((*hashval++ & 1u) == 0);
1424 obj->dynsymcount += obj->symndx_gnu;
1427 if (obj->linkmap.l_refname != NULL)
1428 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj->
1433 obj_resolve_origin(Obj_Entry *obj)
1436 if (obj->origin_path != NULL)
1438 obj->origin_path = xmalloc(PATH_MAX);
1439 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1443 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1444 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1447 if (obj->z_origin && !obj_resolve_origin(obj))
1450 if (dyn_runpath != NULL) {
1451 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1452 obj->runpath = origin_subst(obj, obj->runpath);
1453 } else if (dyn_rpath != NULL) {
1454 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1455 obj->rpath = origin_subst(obj, obj->rpath);
1457 if (dyn_soname != NULL)
1458 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1463 digest_dynamic(Obj_Entry *obj, int early)
1465 const Elf_Dyn *dyn_rpath;
1466 const Elf_Dyn *dyn_soname;
1467 const Elf_Dyn *dyn_runpath;
1469 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1470 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1474 * Process a shared object's program header. This is used only for the
1475 * main program, when the kernel has already loaded the main program
1476 * into memory before calling the dynamic linker. It creates and
1477 * returns an Obj_Entry structure.
1480 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1483 const Elf_Phdr *phlimit = phdr + phnum;
1485 Elf_Addr note_start, note_end;
1489 for (ph = phdr; ph < phlimit; ph++) {
1490 if (ph->p_type != PT_PHDR)
1494 obj->phsize = ph->p_memsz;
1495 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1499 obj->stack_flags = PF_X | PF_R | PF_W;
1501 for (ph = phdr; ph < phlimit; ph++) {
1502 switch (ph->p_type) {
1505 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1509 if (nsegs == 0) { /* First load segment */
1510 obj->vaddrbase = trunc_page(ph->p_vaddr);
1511 obj->mapbase = obj->vaddrbase + obj->relocbase;
1512 } else { /* Last load segment */
1513 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1520 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1525 obj->tlssize = ph->p_memsz;
1526 obj->tlsalign = ph->p_align;
1527 obj->tlsinitsize = ph->p_filesz;
1528 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1529 obj->tlspoffset = ph->p_offset;
1533 obj->stack_flags = ph->p_flags;
1537 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1538 obj->relro_size = round_page(ph->p_memsz);
1542 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1543 note_end = note_start + ph->p_filesz;
1544 digest_notes(obj, note_start, note_end);
1549 _rtld_error("%s: too few PT_LOAD segments", path);
1558 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1560 const Elf_Note *note;
1561 const char *note_name;
1564 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1565 note = (const Elf_Note *)((const char *)(note + 1) +
1566 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1567 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1568 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1569 note->n_descsz != sizeof(int32_t))
1571 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1572 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1573 note->n_type != NT_FREEBSD_NOINIT_TAG)
1575 note_name = (const char *)(note + 1);
1576 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1577 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1579 switch (note->n_type) {
1580 case NT_FREEBSD_ABI_TAG:
1581 /* FreeBSD osrel note */
1582 p = (uintptr_t)(note + 1);
1583 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1584 obj->osrel = *(const int32_t *)(p);
1585 dbg("note osrel %d", obj->osrel);
1587 case NT_FREEBSD_FEATURE_CTL:
1588 /* FreeBSD ABI feature control note */
1589 p = (uintptr_t)(note + 1);
1590 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1591 obj->fctl0 = *(const uint32_t *)(p);
1592 dbg("note fctl0 %#x", obj->fctl0);
1594 case NT_FREEBSD_NOINIT_TAG:
1595 /* FreeBSD 'crt does not call init' note */
1596 obj->crt_no_init = true;
1597 dbg("note crt_no_init");
1604 dlcheck(void *handle)
1608 TAILQ_FOREACH(obj, &obj_list, next) {
1609 if (obj == (Obj_Entry *) handle)
1613 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1614 _rtld_error("Invalid shared object handle %p", handle);
1621 * If the given object is already in the donelist, return true. Otherwise
1622 * add the object to the list and return false.
1625 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1629 for (i = 0; i < dlp->num_used; i++)
1630 if (dlp->objs[i] == obj)
1633 * Our donelist allocation should always be sufficient. But if
1634 * our threads locking isn't working properly, more shared objects
1635 * could have been loaded since we allocated the list. That should
1636 * never happen, but we'll handle it properly just in case it does.
1638 if (dlp->num_used < dlp->num_alloc)
1639 dlp->objs[dlp->num_used++] = obj;
1644 * Hash function for symbol table lookup. Don't even think about changing
1645 * this. It is specified by the System V ABI.
1648 elf_hash(const char *name)
1650 const unsigned char *p = (const unsigned char *) name;
1651 unsigned long h = 0;
1654 while (*p != '\0') {
1655 h = (h << 4) + *p++;
1656 if ((g = h & 0xf0000000) != 0)
1664 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1665 * unsigned in case it's implemented with a wider type.
1668 gnu_hash(const char *s)
1674 for (c = *s; c != '\0'; c = *++s)
1676 return (h & 0xffffffff);
1681 * Find the library with the given name, and return its full pathname.
1682 * The returned string is dynamically allocated. Generates an error
1683 * message and returns NULL if the library cannot be found.
1685 * If the second argument is non-NULL, then it refers to an already-
1686 * loaded shared object, whose library search path will be searched.
1688 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1689 * descriptor (which is close-on-exec) will be passed out via the third
1692 * The search order is:
1693 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1694 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1696 * DT_RUNPATH in the referencing file
1697 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1699 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1701 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1704 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1706 char *pathname, *refobj_path;
1708 bool nodeflib, objgiven;
1710 objgiven = refobj != NULL;
1712 if (libmap_disable || !objgiven ||
1713 (name = lm_find(refobj->path, xname)) == NULL)
1716 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1717 if (name[0] != '/' && !trust) {
1718 _rtld_error("Absolute pathname required "
1719 "for shared object \"%s\"", name);
1722 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1723 __DECONST(char *, name)));
1726 dbg(" Searching for \"%s\"", name);
1727 refobj_path = objgiven ? refobj->path : NULL;
1730 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1731 * back to pre-conforming behaviour if user requested so with
1732 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1735 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1736 pathname = search_library_path(name, ld_library_path,
1738 if (pathname != NULL)
1740 if (refobj != NULL) {
1741 pathname = search_library_path(name, refobj->rpath,
1743 if (pathname != NULL)
1746 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1747 if (pathname != NULL)
1749 pathname = search_library_path(name, gethints(false),
1751 if (pathname != NULL)
1753 pathname = search_library_path(name, ld_standard_library_path,
1755 if (pathname != NULL)
1758 nodeflib = objgiven ? refobj->z_nodeflib : false;
1760 pathname = search_library_path(name, refobj->rpath,
1762 if (pathname != NULL)
1765 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1766 pathname = search_library_path(name, obj_main->rpath,
1768 if (pathname != NULL)
1771 pathname = search_library_path(name, ld_library_path,
1773 if (pathname != NULL)
1776 pathname = search_library_path(name, refobj->runpath,
1778 if (pathname != NULL)
1781 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1782 if (pathname != NULL)
1784 pathname = search_library_path(name, gethints(nodeflib),
1786 if (pathname != NULL)
1788 if (objgiven && !nodeflib) {
1789 pathname = search_library_path(name,
1790 ld_standard_library_path, refobj_path, fdp);
1791 if (pathname != NULL)
1796 if (objgiven && refobj->path != NULL) {
1797 _rtld_error("Shared object \"%s\" not found, "
1798 "required by \"%s\"", name, basename(refobj->path));
1800 _rtld_error("Shared object \"%s\" not found", name);
1806 * Given a symbol number in a referencing object, find the corresponding
1807 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1808 * no definition was found. Returns a pointer to the Obj_Entry of the
1809 * defining object via the reference parameter DEFOBJ_OUT.
1812 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1813 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1814 RtldLockState *lockstate)
1818 const Obj_Entry *defobj;
1819 const Ver_Entry *ve;
1825 * If we have already found this symbol, get the information from
1828 if (symnum >= refobj->dynsymcount)
1829 return NULL; /* Bad object */
1830 if (cache != NULL && cache[symnum].sym != NULL) {
1831 *defobj_out = cache[symnum].obj;
1832 return cache[symnum].sym;
1835 ref = refobj->symtab + symnum;
1836 name = refobj->strtab + ref->st_name;
1842 * We don't have to do a full scale lookup if the symbol is local.
1843 * We know it will bind to the instance in this load module; to
1844 * which we already have a pointer (ie ref). By not doing a lookup,
1845 * we not only improve performance, but it also avoids unresolvable
1846 * symbols when local symbols are not in the hash table. This has
1847 * been seen with the ia64 toolchain.
1849 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1850 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1851 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1854 symlook_init(&req, name);
1856 ve = req.ventry = fetch_ventry(refobj, symnum);
1857 req.lockstate = lockstate;
1858 res = symlook_default(&req, refobj);
1861 defobj = req.defobj_out;
1869 * If we found no definition and the reference is weak, treat the
1870 * symbol as having the value zero.
1872 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1878 *defobj_out = defobj;
1879 /* Record the information in the cache to avoid subsequent lookups. */
1880 if (cache != NULL) {
1881 cache[symnum].sym = def;
1882 cache[symnum].obj = defobj;
1885 if (refobj != &obj_rtld)
1886 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1887 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1893 * Return the search path from the ldconfig hints file, reading it if
1894 * necessary. If nostdlib is true, then the default search paths are
1895 * not added to result.
1897 * Returns NULL if there are problems with the hints file,
1898 * or if the search path there is empty.
1901 gethints(bool nostdlib)
1903 static char *filtered_path;
1904 static const char *hints;
1905 static struct elfhints_hdr hdr;
1906 struct fill_search_info_args sargs, hargs;
1907 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1908 struct dl_serpath *SLPpath, *hintpath;
1910 struct stat hint_stat;
1911 unsigned int SLPndx, hintndx, fndx, fcount;
1917 /* First call, read the hints file */
1918 if (hints == NULL) {
1919 /* Keep from trying again in case the hints file is bad. */
1922 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1926 * Check of hdr.dirlistlen value against type limit
1927 * intends to pacify static analyzers. Further
1928 * paranoia leads to checks that dirlist is fully
1929 * contained in the file range.
1931 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1932 hdr.magic != ELFHINTS_MAGIC ||
1933 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1934 fstat(fd, &hint_stat) == -1) {
1941 if (dl + hdr.dirlist < dl)
1944 if (dl + hdr.dirlistlen < dl)
1946 dl += hdr.dirlistlen;
1947 if (dl > hint_stat.st_size)
1949 p = xmalloc(hdr.dirlistlen + 1);
1950 if (pread(fd, p, hdr.dirlistlen + 1,
1951 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1952 p[hdr.dirlistlen] != '\0') {
1961 * If caller agreed to receive list which includes the default
1962 * paths, we are done. Otherwise, if we still did not
1963 * calculated filtered result, do it now.
1966 return (hints[0] != '\0' ? hints : NULL);
1967 if (filtered_path != NULL)
1971 * Obtain the list of all configured search paths, and the
1972 * list of the default paths.
1974 * First estimate the size of the results.
1976 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1978 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1981 sargs.request = RTLD_DI_SERINFOSIZE;
1982 sargs.serinfo = &smeta;
1983 hargs.request = RTLD_DI_SERINFOSIZE;
1984 hargs.serinfo = &hmeta;
1986 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1988 path_enumerate(hints, fill_search_info, NULL, &hargs);
1990 SLPinfo = xmalloc(smeta.dls_size);
1991 hintinfo = xmalloc(hmeta.dls_size);
1994 * Next fetch both sets of paths.
1996 sargs.request = RTLD_DI_SERINFO;
1997 sargs.serinfo = SLPinfo;
1998 sargs.serpath = &SLPinfo->dls_serpath[0];
1999 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
2001 hargs.request = RTLD_DI_SERINFO;
2002 hargs.serinfo = hintinfo;
2003 hargs.serpath = &hintinfo->dls_serpath[0];
2004 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
2006 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
2008 path_enumerate(hints, fill_search_info, NULL, &hargs);
2011 * Now calculate the difference between two sets, by excluding
2012 * standard paths from the full set.
2016 filtered_path = xmalloc(hdr.dirlistlen + 1);
2017 hintpath = &hintinfo->dls_serpath[0];
2018 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
2020 SLPpath = &SLPinfo->dls_serpath[0];
2022 * Check each standard path against current.
2024 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
2025 /* matched, skip the path */
2026 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
2034 * Not matched against any standard path, add the path
2035 * to result. Separate consequtive paths with ':'.
2038 filtered_path[fndx] = ':';
2042 flen = strlen(hintpath->dls_name);
2043 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
2046 filtered_path[fndx] = '\0';
2052 return (filtered_path[0] != '\0' ? filtered_path : NULL);
2056 init_dag(Obj_Entry *root)
2058 const Needed_Entry *needed;
2059 const Objlist_Entry *elm;
2062 if (root->dag_inited)
2064 donelist_init(&donelist);
2066 /* Root object belongs to own DAG. */
2067 objlist_push_tail(&root->dldags, root);
2068 objlist_push_tail(&root->dagmembers, root);
2069 donelist_check(&donelist, root);
2072 * Add dependencies of root object to DAG in breadth order
2073 * by exploiting the fact that each new object get added
2074 * to the tail of the dagmembers list.
2076 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2077 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
2078 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
2080 objlist_push_tail(&needed->obj->dldags, root);
2081 objlist_push_tail(&root->dagmembers, needed->obj);
2084 root->dag_inited = true;
2088 init_marker(Obj_Entry *marker)
2091 bzero(marker, sizeof(*marker));
2092 marker->marker = true;
2096 globallist_curr(const Obj_Entry *obj)
2103 return (__DECONST(Obj_Entry *, obj));
2104 obj = TAILQ_PREV(obj, obj_entry_q, next);
2109 globallist_next(const Obj_Entry *obj)
2113 obj = TAILQ_NEXT(obj, next);
2117 return (__DECONST(Obj_Entry *, obj));
2121 /* Prevent the object from being unmapped while the bind lock is dropped. */
2123 hold_object(Obj_Entry *obj)
2130 unhold_object(Obj_Entry *obj)
2133 assert(obj->holdcount > 0);
2134 if (--obj->holdcount == 0 && obj->unholdfree)
2135 release_object(obj);
2139 process_z(Obj_Entry *root)
2141 const Objlist_Entry *elm;
2145 * Walk over object DAG and process every dependent object
2146 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2147 * to grow their own DAG.
2149 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2150 * symlook_global() to work.
2152 * For DF_1_NODELETE, the DAG should have its reference upped.
2154 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2158 if (obj->z_nodelete && !obj->ref_nodel) {
2159 dbg("obj %s -z nodelete", obj->path);
2162 obj->ref_nodel = true;
2164 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2165 dbg("obj %s -z global", obj->path);
2166 objlist_push_tail(&list_global, obj);
2173 parse_rtld_phdr(Obj_Entry *obj)
2176 Elf_Addr note_start, note_end;
2178 obj->stack_flags = PF_X | PF_R | PF_W;
2179 for (ph = obj->phdr; (const char *)ph < (const char *)obj->phdr +
2180 obj->phsize; ph++) {
2181 switch (ph->p_type) {
2183 obj->stack_flags = ph->p_flags;
2186 obj->relro_page = obj->relocbase +
2187 trunc_page(ph->p_vaddr);
2188 obj->relro_size = round_page(ph->p_memsz);
2191 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
2192 note_end = note_start + ph->p_filesz;
2193 digest_notes(obj, note_start, note_end);
2200 * Initialize the dynamic linker. The argument is the address at which
2201 * the dynamic linker has been mapped into memory. The primary task of
2202 * this function is to relocate the dynamic linker.
2205 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2207 Obj_Entry objtmp; /* Temporary rtld object */
2208 const Elf_Ehdr *ehdr;
2209 const Elf_Dyn *dyn_rpath;
2210 const Elf_Dyn *dyn_soname;
2211 const Elf_Dyn *dyn_runpath;
2213 #ifdef RTLD_INIT_PAGESIZES_EARLY
2214 /* The page size is required by the dynamic memory allocator. */
2215 init_pagesizes(aux_info);
2219 * Conjure up an Obj_Entry structure for the dynamic linker.
2221 * The "path" member can't be initialized yet because string constants
2222 * cannot yet be accessed. Below we will set it correctly.
2224 memset(&objtmp, 0, sizeof(objtmp));
2227 objtmp.mapbase = mapbase;
2229 objtmp.relocbase = mapbase;
2232 objtmp.dynamic = rtld_dynamic(&objtmp);
2233 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2234 assert(objtmp.needed == NULL);
2235 #if !defined(__mips__)
2236 /* MIPS has a bogus DT_TEXTREL. */
2237 assert(!objtmp.textrel);
2240 * Temporarily put the dynamic linker entry into the object list, so
2241 * that symbols can be found.
2243 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2245 ehdr = (Elf_Ehdr *)mapbase;
2246 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2247 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2249 /* Initialize the object list. */
2250 TAILQ_INIT(&obj_list);
2252 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2253 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2255 #ifndef RTLD_INIT_PAGESIZES_EARLY
2256 /* The page size is required by the dynamic memory allocator. */
2257 init_pagesizes(aux_info);
2260 if (aux_info[AT_OSRELDATE] != NULL)
2261 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2263 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2265 /* Replace the path with a dynamically allocated copy. */
2266 obj_rtld.path = xstrdup(ld_path_rtld);
2268 parse_rtld_phdr(&obj_rtld);
2269 obj_enforce_relro(&obj_rtld);
2271 r_debug.r_version = R_DEBUG_VERSION;
2272 r_debug.r_brk = r_debug_state;
2273 r_debug.r_state = RT_CONSISTENT;
2274 r_debug.r_ldbase = obj_rtld.relocbase;
2278 * Retrieve the array of supported page sizes. The kernel provides the page
2279 * sizes in increasing order.
2282 init_pagesizes(Elf_Auxinfo **aux_info)
2284 static size_t psa[MAXPAGESIZES];
2288 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2290 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2291 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2294 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2297 /* As a fallback, retrieve the base page size. */
2298 size = sizeof(psa[0]);
2299 if (aux_info[AT_PAGESZ] != NULL) {
2300 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2304 mib[1] = HW_PAGESIZE;
2308 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2309 _rtld_error("sysctl for hw.pagesize(s) failed");
2315 npagesizes = size / sizeof(pagesizes[0]);
2316 /* Discard any invalid entries at the end of the array. */
2317 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2322 * Add the init functions from a needed object list (and its recursive
2323 * needed objects) to "list". This is not used directly; it is a helper
2324 * function for initlist_add_objects(). The write lock must be held
2325 * when this function is called.
2328 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2330 /* Recursively process the successor needed objects. */
2331 if (needed->next != NULL)
2332 initlist_add_neededs(needed->next, list);
2334 /* Process the current needed object. */
2335 if (needed->obj != NULL)
2336 initlist_add_objects(needed->obj, needed->obj, list);
2340 * Scan all of the DAGs rooted in the range of objects from "obj" to
2341 * "tail" and add their init functions to "list". This recurses over
2342 * the DAGs and ensure the proper init ordering such that each object's
2343 * needed libraries are initialized before the object itself. At the
2344 * same time, this function adds the objects to the global finalization
2345 * list "list_fini" in the opposite order. The write lock must be
2346 * held when this function is called.
2349 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2353 if (obj->init_scanned || obj->init_done)
2355 obj->init_scanned = true;
2357 /* Recursively process the successor objects. */
2358 nobj = globallist_next(obj);
2359 if (nobj != NULL && obj != tail)
2360 initlist_add_objects(nobj, tail, list);
2362 /* Recursively process the needed objects. */
2363 if (obj->needed != NULL)
2364 initlist_add_neededs(obj->needed, list);
2365 if (obj->needed_filtees != NULL)
2366 initlist_add_neededs(obj->needed_filtees, list);
2367 if (obj->needed_aux_filtees != NULL)
2368 initlist_add_neededs(obj->needed_aux_filtees, list);
2370 /* Add the object to the init list. */
2371 objlist_push_tail(list, obj);
2373 /* Add the object to the global fini list in the reverse order. */
2374 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2375 && !obj->on_fini_list) {
2376 objlist_push_head(&list_fini, obj);
2377 obj->on_fini_list = true;
2382 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2386 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2388 Needed_Entry *needed, *needed1;
2390 for (needed = n; needed != NULL; needed = needed->next) {
2391 if (needed->obj != NULL) {
2392 dlclose_locked(needed->obj, lockstate);
2396 for (needed = n; needed != NULL; needed = needed1) {
2397 needed1 = needed->next;
2403 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2406 free_needed_filtees(obj->needed_filtees, lockstate);
2407 obj->needed_filtees = NULL;
2408 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2409 obj->needed_aux_filtees = NULL;
2410 obj->filtees_loaded = false;
2414 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2415 RtldLockState *lockstate)
2418 for (; needed != NULL; needed = needed->next) {
2419 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2420 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2421 RTLD_LOCAL, lockstate);
2426 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2429 lock_restart_for_upgrade(lockstate);
2430 if (!obj->filtees_loaded) {
2431 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2432 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2433 obj->filtees_loaded = true;
2438 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2442 for (; needed != NULL; needed = needed->next) {
2443 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2444 flags & ~RTLD_LO_NOLOAD);
2445 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2452 * Given a shared object, traverse its list of needed objects, and load
2453 * each of them. Returns 0 on success. Generates an error message and
2454 * returns -1 on failure.
2457 load_needed_objects(Obj_Entry *first, int flags)
2461 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2464 if (process_needed(obj, obj->needed, flags) == -1)
2471 load_preload_objects(void)
2473 char *p = ld_preload;
2475 static const char delim[] = " \t:;";
2480 p += strspn(p, delim);
2481 while (*p != '\0') {
2482 size_t len = strcspn(p, delim);
2487 obj = load_object(p, -1, NULL, 0);
2489 return -1; /* XXX - cleanup */
2490 obj->z_interpose = true;
2493 p += strspn(p, delim);
2495 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2500 printable_path(const char *path)
2503 return (path == NULL ? "<unknown>" : path);
2507 * Load a shared object into memory, if it is not already loaded. The
2508 * object may be specified by name or by user-supplied file descriptor
2509 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2512 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2516 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2525 TAILQ_FOREACH(obj, &obj_list, next) {
2526 if (obj->marker || obj->doomed)
2528 if (object_match_name(obj, name))
2532 path = find_library(name, refobj, &fd);
2540 * search_library_pathfds() opens a fresh file descriptor for the
2541 * library, so there is no need to dup().
2543 } else if (fd_u == -1) {
2545 * If we didn't find a match by pathname, or the name is not
2546 * supplied, open the file and check again by device and inode.
2547 * This avoids false mismatches caused by multiple links or ".."
2550 * To avoid a race, we open the file and use fstat() rather than
2553 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2554 _rtld_error("Cannot open \"%s\"", path);
2559 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2561 _rtld_error("Cannot dup fd");
2566 if (fstat(fd, &sb) == -1) {
2567 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2572 TAILQ_FOREACH(obj, &obj_list, next) {
2573 if (obj->marker || obj->doomed)
2575 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2578 if (obj != NULL && name != NULL) {
2579 object_add_name(obj, name);
2584 if (flags & RTLD_LO_NOLOAD) {
2590 /* First use of this object, so we must map it in */
2591 obj = do_load_object(fd, name, path, &sb, flags);
2600 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2607 * but first, make sure that environment variables haven't been
2608 * used to circumvent the noexec flag on a filesystem.
2610 if (dangerous_ld_env) {
2611 if (fstatfs(fd, &fs) != 0) {
2612 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2615 if (fs.f_flags & MNT_NOEXEC) {
2616 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2620 dbg("loading \"%s\"", printable_path(path));
2621 obj = map_object(fd, printable_path(path), sbp);
2626 * If DT_SONAME is present in the object, digest_dynamic2 already
2627 * added it to the object names.
2630 object_add_name(obj, name);
2632 if (!digest_dynamic(obj, 0))
2634 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2635 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2636 if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) {
2637 dbg("refusing to load PIE executable \"%s\"", obj->path);
2638 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
2641 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2643 dbg("refusing to load non-loadable \"%s\"", obj->path);
2644 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2648 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2649 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2652 linkmap_add(obj); /* for GDB & dlinfo() */
2653 max_stack_flags |= obj->stack_flags;
2655 dbg(" %p .. %p: %s", obj->mapbase,
2656 obj->mapbase + obj->mapsize - 1, obj->path);
2658 dbg(" WARNING: %s has impure text", obj->path);
2659 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2665 munmap(obj->mapbase, obj->mapsize);
2671 obj_from_addr(const void *addr)
2675 TAILQ_FOREACH(obj, &obj_list, next) {
2678 if (addr < (void *) obj->mapbase)
2680 if (addr < (void *)(obj->mapbase + obj->mapsize))
2689 Elf_Addr *preinit_addr;
2692 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2693 if (preinit_addr == NULL)
2696 for (index = 0; index < obj_main->preinit_array_num; index++) {
2697 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2698 dbg("calling preinit function for %s at %p", obj_main->path,
2699 (void *)preinit_addr[index]);
2700 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2701 0, 0, obj_main->path);
2702 call_init_pointer(obj_main, preinit_addr[index]);
2708 * Call the finalization functions for each of the objects in "list"
2709 * belonging to the DAG of "root" and referenced once. If NULL "root"
2710 * is specified, every finalization function will be called regardless
2711 * of the reference count and the list elements won't be freed. All of
2712 * the objects are expected to have non-NULL fini functions.
2715 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2719 Elf_Addr *fini_addr;
2722 assert(root == NULL || root->refcount == 1);
2725 root->doomed = true;
2728 * Preserve the current error message since a fini function might
2729 * call into the dynamic linker and overwrite it.
2731 saved_msg = errmsg_save();
2733 STAILQ_FOREACH(elm, list, link) {
2734 if (root != NULL && (elm->obj->refcount != 1 ||
2735 objlist_find(&root->dagmembers, elm->obj) == NULL))
2737 /* Remove object from fini list to prevent recursive invocation. */
2738 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2739 /* Ensure that new references cannot be acquired. */
2740 elm->obj->doomed = true;
2742 hold_object(elm->obj);
2743 lock_release(rtld_bind_lock, lockstate);
2745 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2746 * When this happens, DT_FINI_ARRAY is processed first.
2748 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2749 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2750 for (index = elm->obj->fini_array_num - 1; index >= 0;
2752 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2753 dbg("calling fini function for %s at %p",
2754 elm->obj->path, (void *)fini_addr[index]);
2755 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2756 (void *)fini_addr[index], 0, 0, elm->obj->path);
2757 call_initfini_pointer(elm->obj, fini_addr[index]);
2761 if (elm->obj->fini != (Elf_Addr)NULL) {
2762 dbg("calling fini function for %s at %p", elm->obj->path,
2763 (void *)elm->obj->fini);
2764 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2765 0, 0, elm->obj->path);
2766 call_initfini_pointer(elm->obj, elm->obj->fini);
2768 wlock_acquire(rtld_bind_lock, lockstate);
2769 unhold_object(elm->obj);
2770 /* No need to free anything if process is going down. */
2774 * We must restart the list traversal after every fini call
2775 * because a dlclose() call from the fini function or from
2776 * another thread might have modified the reference counts.
2780 } while (elm != NULL);
2781 errmsg_restore(saved_msg);
2785 * Call the initialization functions for each of the objects in
2786 * "list". All of the objects are expected to have non-NULL init
2790 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2795 Elf_Addr *init_addr;
2796 void (*reg)(void (*)(void));
2800 * Clean init_scanned flag so that objects can be rechecked and
2801 * possibly initialized earlier if any of vectors called below
2802 * cause the change by using dlopen.
2804 TAILQ_FOREACH(obj, &obj_list, next) {
2807 obj->init_scanned = false;
2811 * Preserve the current error message since an init function might
2812 * call into the dynamic linker and overwrite it.
2814 saved_msg = errmsg_save();
2815 STAILQ_FOREACH(elm, list, link) {
2816 if (elm->obj->init_done) /* Initialized early. */
2819 * Race: other thread might try to use this object before current
2820 * one completes the initialization. Not much can be done here
2821 * without better locking.
2823 elm->obj->init_done = true;
2824 hold_object(elm->obj);
2826 if (elm->obj == obj_main && obj_main->crt_no_init) {
2827 reg = (void (*)(void (*)(void)))get_program_var_addr(
2828 "__libc_atexit", lockstate);
2830 lock_release(rtld_bind_lock, lockstate);
2833 rtld_exit_ptr = rtld_nop_exit;
2837 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2838 * When this happens, DT_INIT is processed first.
2840 if (elm->obj->init != (Elf_Addr)NULL) {
2841 dbg("calling init function for %s at %p", elm->obj->path,
2842 (void *)elm->obj->init);
2843 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2844 0, 0, elm->obj->path);
2845 call_init_pointer(elm->obj, elm->obj->init);
2847 init_addr = (Elf_Addr *)elm->obj->init_array;
2848 if (init_addr != NULL) {
2849 for (index = 0; index < elm->obj->init_array_num; index++) {
2850 if (init_addr[index] != 0 && init_addr[index] != 1) {
2851 dbg("calling init function for %s at %p", elm->obj->path,
2852 (void *)init_addr[index]);
2853 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2854 (void *)init_addr[index], 0, 0, elm->obj->path);
2855 call_init_pointer(elm->obj, init_addr[index]);
2859 wlock_acquire(rtld_bind_lock, lockstate);
2860 unhold_object(elm->obj);
2862 errmsg_restore(saved_msg);
2866 objlist_clear(Objlist *list)
2870 while (!STAILQ_EMPTY(list)) {
2871 elm = STAILQ_FIRST(list);
2872 STAILQ_REMOVE_HEAD(list, link);
2877 static Objlist_Entry *
2878 objlist_find(Objlist *list, const Obj_Entry *obj)
2882 STAILQ_FOREACH(elm, list, link)
2883 if (elm->obj == obj)
2889 objlist_init(Objlist *list)
2895 objlist_push_head(Objlist *list, Obj_Entry *obj)
2899 elm = NEW(Objlist_Entry);
2901 STAILQ_INSERT_HEAD(list, elm, link);
2905 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2909 elm = NEW(Objlist_Entry);
2911 STAILQ_INSERT_TAIL(list, elm, link);
2915 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2917 Objlist_Entry *elm, *listelm;
2919 STAILQ_FOREACH(listelm, list, link) {
2920 if (listelm->obj == listobj)
2923 elm = NEW(Objlist_Entry);
2925 if (listelm != NULL)
2926 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2928 STAILQ_INSERT_TAIL(list, elm, link);
2932 objlist_remove(Objlist *list, Obj_Entry *obj)
2936 if ((elm = objlist_find(list, obj)) != NULL) {
2937 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2943 * Relocate dag rooted in the specified object.
2944 * Returns 0 on success, or -1 on failure.
2948 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2949 int flags, RtldLockState *lockstate)
2955 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2956 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2965 * Prepare for, or clean after, relocating an object marked with
2966 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2967 * segments are remapped read-write. After relocations are done, the
2968 * segment's permissions are returned back to the modes specified in
2969 * the phdrs. If any relocation happened, or always for wired
2970 * program, COW is triggered.
2973 reloc_textrel_prot(Obj_Entry *obj, bool before)
2980 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2982 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2984 base = obj->relocbase + trunc_page(ph->p_vaddr);
2985 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2986 trunc_page(ph->p_vaddr);
2987 prot = before ? (PROT_READ | PROT_WRITE) :
2988 convert_prot(ph->p_flags);
2989 if (mprotect(base, sz, prot) == -1) {
2990 _rtld_error("%s: Cannot write-%sable text segment: %s",
2991 obj->path, before ? "en" : "dis",
2992 rtld_strerror(errno));
3000 * Relocate single object.
3001 * Returns 0 on success, or -1 on failure.
3004 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
3005 int flags, RtldLockState *lockstate)
3010 obj->relocated = true;
3012 dbg("relocating \"%s\"", obj->path);
3014 if (obj->symtab == NULL || obj->strtab == NULL ||
3015 !(obj->valid_hash_sysv || obj->valid_hash_gnu))
3016 dbg("object %s has no run-time symbol table", obj->path);
3018 /* There are relocations to the write-protected text segment. */
3019 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
3022 /* Process the non-PLT non-IFUNC relocations. */
3023 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
3026 /* Re-protected the text segment. */
3027 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
3030 /* Set the special PLT or GOT entries. */
3033 /* Process the PLT relocations. */
3034 if (reloc_plt(obj, flags, lockstate) == -1)
3036 /* Relocate the jump slots if we are doing immediate binding. */
3037 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
3041 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
3045 * Set up the magic number and version in the Obj_Entry. These
3046 * were checked in the crt1.o from the original ElfKit, so we
3047 * set them for backward compatibility.
3049 obj->magic = RTLD_MAGIC;
3050 obj->version = RTLD_VERSION;
3056 * Relocate newly-loaded shared objects. The argument is a pointer to
3057 * the Obj_Entry for the first such object. All objects from the first
3058 * to the end of the list of objects are relocated. Returns 0 on success,
3062 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
3063 int flags, RtldLockState *lockstate)
3068 for (error = 0, obj = first; obj != NULL;
3069 obj = TAILQ_NEXT(obj, next)) {
3072 error = relocate_object(obj, bind_now, rtldobj, flags,
3081 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
3082 * referencing STT_GNU_IFUNC symbols is postponed till the other
3083 * relocations are done. The indirect functions specified as
3084 * ifunc are allowed to call other symbols, so we need to have
3085 * objects relocated before asking for resolution from indirects.
3087 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
3088 * instead of the usual lazy handling of PLT slots. It is
3089 * consistent with how GNU does it.
3092 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
3093 RtldLockState *lockstate)
3096 if (obj->ifuncs_resolved)
3098 obj->ifuncs_resolved = true;
3099 if (!obj->irelative && !obj->irelative_nonplt &&
3100 !((obj->bind_now || bind_now) && obj->gnu_ifunc) &&
3101 !obj->non_plt_gnu_ifunc)
3103 if (obj_disable_relro(obj) == -1 ||
3104 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3105 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj,
3106 lockstate) == -1) ||
3107 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3108 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3109 (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld,
3110 flags | SYMLOOK_IFUNC, lockstate) == -1) ||
3111 obj_enforce_relro(obj) == -1)
3117 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3118 RtldLockState *lockstate)
3123 STAILQ_FOREACH(elm, list, link) {
3127 if (resolve_object_ifunc(obj, bind_now, flags,
3135 * Cleanup procedure. It will be called (by the atexit mechanism) just
3136 * before the process exits.
3141 RtldLockState lockstate;
3143 wlock_acquire(rtld_bind_lock, &lockstate);
3145 objlist_call_fini(&list_fini, NULL, &lockstate);
3146 /* No need to remove the items from the list, since we are exiting. */
3147 if (!libmap_disable)
3149 lock_release(rtld_bind_lock, &lockstate);
3158 * Iterate over a search path, translate each element, and invoke the
3159 * callback on the result.
3162 path_enumerate(const char *path, path_enum_proc callback,
3163 const char *refobj_path, void *arg)
3169 path += strspn(path, ":;");
3170 while (*path != '\0') {
3174 len = strcspn(path, ":;");
3175 trans = lm_findn(refobj_path, path, len);
3177 res = callback(trans, strlen(trans), arg);
3179 res = callback(path, len, arg);
3185 path += strspn(path, ":;");
3191 struct try_library_args {
3200 try_library_path(const char *dir, size_t dirlen, void *param)
3202 struct try_library_args *arg;
3206 if (*dir == '/' || trust) {
3209 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3212 pathname = arg->buffer;
3213 strncpy(pathname, dir, dirlen);
3214 pathname[dirlen] = '/';
3215 strcpy(pathname + dirlen + 1, arg->name);
3217 dbg(" Trying \"%s\"", pathname);
3218 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3220 dbg(" Opened \"%s\", fd %d", pathname, fd);
3221 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3222 strcpy(pathname, arg->buffer);
3226 dbg(" Failed to open \"%s\": %s",
3227 pathname, rtld_strerror(errno));
3234 search_library_path(const char *name, const char *path,
3235 const char *refobj_path, int *fdp)
3238 struct try_library_args arg;
3244 arg.namelen = strlen(name);
3245 arg.buffer = xmalloc(PATH_MAX);
3246 arg.buflen = PATH_MAX;
3249 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3259 * Finds the library with the given name using the directory descriptors
3260 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3262 * Returns a freshly-opened close-on-exec file descriptor for the library,
3263 * or -1 if the library cannot be found.
3266 search_library_pathfds(const char *name, const char *path, int *fdp)
3268 char *envcopy, *fdstr, *found, *last_token;
3272 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3274 /* Don't load from user-specified libdirs into setuid binaries. */
3278 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3282 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3283 if (name[0] == '/') {
3284 dbg("Absolute path (%s) passed to %s", name, __func__);
3289 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3290 * copy of the path, as strtok_r rewrites separator tokens
3294 envcopy = xstrdup(path);
3295 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3296 fdstr = strtok_r(NULL, ":", &last_token)) {
3297 dirfd = parse_integer(fdstr);
3299 _rtld_error("failed to parse directory FD: '%s'",
3303 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3306 len = strlen(fdstr) + strlen(name) + 3;
3307 found = xmalloc(len);
3308 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3309 _rtld_error("error generating '%d/%s'",
3313 dbg("open('%s') => %d", found, fd);
3324 dlclose(void *handle)
3326 RtldLockState lockstate;
3329 wlock_acquire(rtld_bind_lock, &lockstate);
3330 error = dlclose_locked(handle, &lockstate);
3331 lock_release(rtld_bind_lock, &lockstate);
3336 dlclose_locked(void *handle, RtldLockState *lockstate)
3340 root = dlcheck(handle);
3343 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3346 /* Unreference the object and its dependencies. */
3347 root->dl_refcount--;
3349 if (root->refcount == 1) {
3351 * The object will be no longer referenced, so we must unload it.
3352 * First, call the fini functions.
3354 objlist_call_fini(&list_fini, root, lockstate);
3358 /* Finish cleaning up the newly-unreferenced objects. */
3359 GDB_STATE(RT_DELETE,&root->linkmap);
3360 unload_object(root, lockstate);
3361 GDB_STATE(RT_CONSISTENT,NULL);
3365 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3372 char *msg = error_message;
3373 error_message = NULL;
3378 * This function is deprecated and has no effect.
3381 dllockinit(void *context,
3382 void *(*_lock_create)(void *context) __unused,
3383 void (*_rlock_acquire)(void *lock) __unused,
3384 void (*_wlock_acquire)(void *lock) __unused,
3385 void (*_lock_release)(void *lock) __unused,
3386 void (*_lock_destroy)(void *lock) __unused,
3387 void (*context_destroy)(void *context))
3389 static void *cur_context;
3390 static void (*cur_context_destroy)(void *);
3392 /* Just destroy the context from the previous call, if necessary. */
3393 if (cur_context_destroy != NULL)
3394 cur_context_destroy(cur_context);
3395 cur_context = context;
3396 cur_context_destroy = context_destroy;
3400 dlopen(const char *name, int mode)
3403 return (rtld_dlopen(name, -1, mode));
3407 fdlopen(int fd, int mode)
3410 return (rtld_dlopen(NULL, fd, mode));
3414 rtld_dlopen(const char *name, int fd, int mode)
3416 RtldLockState lockstate;
3419 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3420 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3421 if (ld_tracing != NULL) {
3422 rlock_acquire(rtld_bind_lock, &lockstate);
3423 if (sigsetjmp(lockstate.env, 0) != 0)
3424 lock_upgrade(rtld_bind_lock, &lockstate);
3425 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3426 lock_release(rtld_bind_lock, &lockstate);
3428 lo_flags = RTLD_LO_DLOPEN;
3429 if (mode & RTLD_NODELETE)
3430 lo_flags |= RTLD_LO_NODELETE;
3431 if (mode & RTLD_NOLOAD)
3432 lo_flags |= RTLD_LO_NOLOAD;
3433 if (mode & RTLD_DEEPBIND)
3434 lo_flags |= RTLD_LO_DEEPBIND;
3435 if (ld_tracing != NULL)
3436 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3438 return (dlopen_object(name, fd, obj_main, lo_flags,
3439 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3443 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3448 if (obj->refcount == 0)
3449 unload_object(obj, lockstate);
3453 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3454 int mode, RtldLockState *lockstate)
3456 Obj_Entry *old_obj_tail;
3459 RtldLockState mlockstate;
3462 dbg("dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x",
3463 name != NULL ? name : "<null>", fd, refobj == NULL ? "<null>" :
3464 refobj->path, lo_flags, mode);
3465 objlist_init(&initlist);
3467 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3468 wlock_acquire(rtld_bind_lock, &mlockstate);
3469 lockstate = &mlockstate;
3471 GDB_STATE(RT_ADD,NULL);
3473 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3475 if (name == NULL && fd == -1) {
3479 obj = load_object(name, fd, refobj, lo_flags);
3484 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3485 objlist_push_tail(&list_global, obj);
3486 if (globallist_next(old_obj_tail) != NULL) {
3487 /* We loaded something new. */
3488 assert(globallist_next(old_obj_tail) == obj);
3489 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
3490 obj->symbolic = true;
3492 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 &&
3493 obj->static_tls && !allocate_tls_offset(obj)) {
3494 _rtld_error("%s: No space available "
3495 "for static Thread Local Storage", obj->path);
3499 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3500 RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE));
3504 result = rtld_verify_versions(&obj->dagmembers);
3505 if (result != -1 && ld_tracing)
3507 if (result == -1 || relocate_object_dag(obj,
3508 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3509 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3511 dlopen_cleanup(obj, lockstate);
3513 } else if (lo_flags & RTLD_LO_EARLY) {
3515 * Do not call the init functions for early loaded
3516 * filtees. The image is still not initialized enough
3519 * Our object is found by the global object list and
3520 * will be ordered among all init calls done right
3521 * before transferring control to main.
3524 /* Make list of init functions to call. */
3525 initlist_add_objects(obj, obj, &initlist);
3528 * Process all no_delete or global objects here, given
3529 * them own DAGs to prevent their dependencies from being
3530 * unloaded. This has to be done after we have loaded all
3531 * of the dependencies, so that we do not miss any.
3537 * Bump the reference counts for objects on this DAG. If
3538 * this is the first dlopen() call for the object that was
3539 * already loaded as a dependency, initialize the dag
3545 if ((lo_flags & RTLD_LO_TRACE) != 0)
3548 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3549 obj->z_nodelete) && !obj->ref_nodel) {
3550 dbg("obj %s nodelete", obj->path);
3552 obj->z_nodelete = obj->ref_nodel = true;
3556 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3558 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3560 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3561 map_stacks_exec(lockstate);
3563 distribute_static_tls(&initlist, lockstate);
3566 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3567 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3569 objlist_clear(&initlist);
3570 dlopen_cleanup(obj, lockstate);
3571 if (lockstate == &mlockstate)
3572 lock_release(rtld_bind_lock, lockstate);
3576 if (!(lo_flags & RTLD_LO_EARLY)) {
3577 /* Call the init functions. */
3578 objlist_call_init(&initlist, lockstate);
3580 objlist_clear(&initlist);
3581 if (lockstate == &mlockstate)
3582 lock_release(rtld_bind_lock, lockstate);
3585 trace_loaded_objects(obj);
3586 if (lockstate == &mlockstate)
3587 lock_release(rtld_bind_lock, lockstate);
3592 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3596 const Obj_Entry *obj, *defobj;
3599 RtldLockState lockstate;
3606 symlook_init(&req, name);
3608 req.flags = flags | SYMLOOK_IN_PLT;
3609 req.lockstate = &lockstate;
3611 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3612 rlock_acquire(rtld_bind_lock, &lockstate);
3613 if (sigsetjmp(lockstate.env, 0) != 0)
3614 lock_upgrade(rtld_bind_lock, &lockstate);
3615 if (handle == NULL || handle == RTLD_NEXT ||
3616 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3618 if ((obj = obj_from_addr(retaddr)) == NULL) {
3619 _rtld_error("Cannot determine caller's shared object");
3620 lock_release(rtld_bind_lock, &lockstate);
3621 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3624 if (handle == NULL) { /* Just the caller's shared object. */
3625 res = symlook_obj(&req, obj);
3628 defobj = req.defobj_out;
3630 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3631 handle == RTLD_SELF) { /* ... caller included */
3632 if (handle == RTLD_NEXT)
3633 obj = globallist_next(obj);
3634 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3637 res = symlook_obj(&req, obj);
3640 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3642 defobj = req.defobj_out;
3643 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3649 * Search the dynamic linker itself, and possibly resolve the
3650 * symbol from there. This is how the application links to
3651 * dynamic linker services such as dlopen.
3653 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3654 res = symlook_obj(&req, &obj_rtld);
3657 defobj = req.defobj_out;
3661 assert(handle == RTLD_DEFAULT);
3662 res = symlook_default(&req, obj);
3664 defobj = req.defobj_out;
3669 if ((obj = dlcheck(handle)) == NULL) {
3670 lock_release(rtld_bind_lock, &lockstate);
3671 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3675 donelist_init(&donelist);
3676 if (obj->mainprog) {
3677 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3678 res = symlook_global(&req, &donelist);
3681 defobj = req.defobj_out;
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;
3697 /* Search the whole DAG rooted at the given object. */
3698 res = symlook_list(&req, &obj->dagmembers, &donelist);
3701 defobj = req.defobj_out;
3707 lock_release(rtld_bind_lock, &lockstate);
3710 * The value required by the caller is derived from the value
3711 * of the symbol. this is simply the relocated value of the
3714 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3715 sym = make_function_pointer(def, defobj);
3716 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3717 sym = rtld_resolve_ifunc(defobj, def);
3718 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3719 ti.ti_module = defobj->tlsindex;
3720 ti.ti_offset = def->st_value;
3721 sym = __tls_get_addr(&ti);
3723 sym = defobj->relocbase + def->st_value;
3724 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3728 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3729 ve != NULL ? ve->name : "");
3730 lock_release(rtld_bind_lock, &lockstate);
3731 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3736 dlsym(void *handle, const char *name)
3738 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3743 dlfunc(void *handle, const char *name)
3750 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3756 dlvsym(void *handle, const char *name, const char *version)
3760 ventry.name = version;
3762 ventry.hash = elf_hash(version);
3764 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3769 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3771 const Obj_Entry *obj;
3772 RtldLockState lockstate;
3774 rlock_acquire(rtld_bind_lock, &lockstate);
3775 obj = obj_from_addr(addr);
3777 _rtld_error("No shared object contains address");
3778 lock_release(rtld_bind_lock, &lockstate);
3781 rtld_fill_dl_phdr_info(obj, phdr_info);
3782 lock_release(rtld_bind_lock, &lockstate);
3787 dladdr(const void *addr, Dl_info *info)
3789 const Obj_Entry *obj;
3792 unsigned long symoffset;
3793 RtldLockState lockstate;
3795 rlock_acquire(rtld_bind_lock, &lockstate);
3796 obj = obj_from_addr(addr);
3798 _rtld_error("No shared object contains address");
3799 lock_release(rtld_bind_lock, &lockstate);
3802 info->dli_fname = obj->path;
3803 info->dli_fbase = obj->mapbase;
3804 info->dli_saddr = (void *)0;
3805 info->dli_sname = NULL;
3808 * Walk the symbol list looking for the symbol whose address is
3809 * closest to the address sent in.
3811 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3812 def = obj->symtab + symoffset;
3815 * For skip the symbol if st_shndx is either SHN_UNDEF or
3818 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3822 * If the symbol is greater than the specified address, or if it
3823 * is further away from addr than the current nearest symbol,
3826 symbol_addr = obj->relocbase + def->st_value;
3827 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3830 /* Update our idea of the nearest symbol. */
3831 info->dli_sname = obj->strtab + def->st_name;
3832 info->dli_saddr = symbol_addr;
3835 if (info->dli_saddr == addr)
3838 lock_release(rtld_bind_lock, &lockstate);
3843 dlinfo(void *handle, int request, void *p)
3845 const Obj_Entry *obj;
3846 RtldLockState lockstate;
3849 rlock_acquire(rtld_bind_lock, &lockstate);
3851 if (handle == NULL || handle == RTLD_SELF) {
3854 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3855 if ((obj = obj_from_addr(retaddr)) == NULL)
3856 _rtld_error("Cannot determine caller's shared object");
3858 obj = dlcheck(handle);
3861 lock_release(rtld_bind_lock, &lockstate);
3867 case RTLD_DI_LINKMAP:
3868 *((struct link_map const **)p) = &obj->linkmap;
3870 case RTLD_DI_ORIGIN:
3871 error = rtld_dirname(obj->path, p);
3874 case RTLD_DI_SERINFOSIZE:
3875 case RTLD_DI_SERINFO:
3876 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3880 _rtld_error("Invalid request %d passed to dlinfo()", request);
3884 lock_release(rtld_bind_lock, &lockstate);
3890 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3893 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3894 phdr_info->dlpi_name = obj->path;
3895 phdr_info->dlpi_phdr = obj->phdr;
3896 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3897 phdr_info->dlpi_tls_modid = obj->tlsindex;
3898 phdr_info->dlpi_tls_data = obj->tlsinit;
3899 phdr_info->dlpi_adds = obj_loads;
3900 phdr_info->dlpi_subs = obj_loads - obj_count;
3904 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3906 struct dl_phdr_info phdr_info;
3907 Obj_Entry *obj, marker;
3908 RtldLockState bind_lockstate, phdr_lockstate;
3911 init_marker(&marker);
3914 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3915 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3916 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3917 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3918 rtld_fill_dl_phdr_info(obj, &phdr_info);
3920 lock_release(rtld_bind_lock, &bind_lockstate);
3922 error = callback(&phdr_info, sizeof phdr_info, param);
3924 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3926 obj = globallist_next(&marker);
3927 TAILQ_REMOVE(&obj_list, &marker, next);
3929 lock_release(rtld_bind_lock, &bind_lockstate);
3930 lock_release(rtld_phdr_lock, &phdr_lockstate);
3936 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3937 lock_release(rtld_bind_lock, &bind_lockstate);
3938 error = callback(&phdr_info, sizeof(phdr_info), param);
3940 lock_release(rtld_phdr_lock, &phdr_lockstate);
3945 fill_search_info(const char *dir, size_t dirlen, void *param)
3947 struct fill_search_info_args *arg;
3951 if (arg->request == RTLD_DI_SERINFOSIZE) {
3952 arg->serinfo->dls_cnt ++;
3953 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3955 struct dl_serpath *s_entry;
3957 s_entry = arg->serpath;
3958 s_entry->dls_name = arg->strspace;
3959 s_entry->dls_flags = arg->flags;
3961 strncpy(arg->strspace, dir, dirlen);
3962 arg->strspace[dirlen] = '\0';
3964 arg->strspace += dirlen + 1;
3972 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3974 struct dl_serinfo _info;
3975 struct fill_search_info_args args;
3977 args.request = RTLD_DI_SERINFOSIZE;
3978 args.serinfo = &_info;
3980 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3983 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3984 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3985 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3986 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3987 if (!obj->z_nodeflib)
3988 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3991 if (request == RTLD_DI_SERINFOSIZE) {
3992 info->dls_size = _info.dls_size;
3993 info->dls_cnt = _info.dls_cnt;
3997 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3998 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
4002 args.request = RTLD_DI_SERINFO;
4003 args.serinfo = info;
4004 args.serpath = &info->dls_serpath[0];
4005 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
4007 args.flags = LA_SER_RUNPATH;
4008 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
4011 args.flags = LA_SER_LIBPATH;
4012 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
4015 args.flags = LA_SER_RUNPATH;
4016 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
4019 args.flags = LA_SER_CONFIG;
4020 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
4024 args.flags = LA_SER_DEFAULT;
4025 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
4026 fill_search_info, NULL, &args) != NULL)
4032 rtld_dirname(const char *path, char *bname)
4036 /* Empty or NULL string gets treated as "." */
4037 if (path == NULL || *path == '\0') {
4043 /* Strip trailing slashes */
4044 endp = path + strlen(path) - 1;
4045 while (endp > path && *endp == '/')
4048 /* Find the start of the dir */
4049 while (endp > path && *endp != '/')
4052 /* Either the dir is "/" or there are no slashes */
4054 bname[0] = *endp == '/' ? '/' : '.';
4060 } while (endp > path && *endp == '/');
4063 if (endp - path + 2 > PATH_MAX)
4065 _rtld_error("Filename is too long: %s", path);
4069 strncpy(bname, path, endp - path + 1);
4070 bname[endp - path + 1] = '\0';
4075 rtld_dirname_abs(const char *path, char *base)
4079 if (realpath(path, base) == NULL) {
4080 _rtld_error("realpath \"%s\" failed (%s)", path,
4081 rtld_strerror(errno));
4084 dbg("%s -> %s", path, base);
4085 last = strrchr(base, '/');
4087 _rtld_error("non-abs result from realpath \"%s\"", path);
4096 linkmap_add(Obj_Entry *obj)
4098 struct link_map *l, *prev;
4101 l->l_name = obj->path;
4102 l->l_base = obj->mapbase;
4103 l->l_ld = obj->dynamic;
4104 l->l_addr = obj->relocbase;
4106 if (r_debug.r_map == NULL) {
4112 * Scan to the end of the list, but not past the entry for the
4113 * dynamic linker, which we want to keep at the very end.
4115 for (prev = r_debug.r_map;
4116 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4117 prev = prev->l_next)
4120 /* Link in the new entry. */
4122 l->l_next = prev->l_next;
4123 if (l->l_next != NULL)
4124 l->l_next->l_prev = l;
4129 linkmap_delete(Obj_Entry *obj)
4134 if (l->l_prev == NULL) {
4135 if ((r_debug.r_map = l->l_next) != NULL)
4136 l->l_next->l_prev = NULL;
4140 if ((l->l_prev->l_next = l->l_next) != NULL)
4141 l->l_next->l_prev = l->l_prev;
4145 * Function for the debugger to set a breakpoint on to gain control.
4147 * The two parameters allow the debugger to easily find and determine
4148 * what the runtime loader is doing and to whom it is doing it.
4150 * When the loadhook trap is hit (r_debug_state, set at program
4151 * initialization), the arguments can be found on the stack:
4153 * +8 struct link_map *m
4154 * +4 struct r_debug *rd
4158 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4161 * The following is a hack to force the compiler to emit calls to
4162 * this function, even when optimizing. If the function is empty,
4163 * the compiler is not obliged to emit any code for calls to it,
4164 * even when marked __noinline. However, gdb depends on those
4167 __compiler_membar();
4171 * A function called after init routines have completed. This can be used to
4172 * break before a program's entry routine is called, and can be used when
4173 * main is not available in the symbol table.
4176 _r_debug_postinit(struct link_map *m __unused)
4179 /* See r_debug_state(). */
4180 __compiler_membar();
4184 release_object(Obj_Entry *obj)
4187 if (obj->holdcount > 0) {
4188 obj->unholdfree = true;
4191 munmap(obj->mapbase, obj->mapsize);
4192 linkmap_delete(obj);
4197 * Get address of the pointer variable in the main program.
4198 * Prefer non-weak symbol over the weak one.
4200 static const void **
4201 get_program_var_addr(const char *name, RtldLockState *lockstate)
4206 symlook_init(&req, name);
4207 req.lockstate = lockstate;
4208 donelist_init(&donelist);
4209 if (symlook_global(&req, &donelist) != 0)
4211 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4212 return ((const void **)make_function_pointer(req.sym_out,
4214 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4215 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4217 return ((const void **)(req.defobj_out->relocbase +
4218 req.sym_out->st_value));
4222 * Set a pointer variable in the main program to the given value. This
4223 * is used to set key variables such as "environ" before any of the
4224 * init functions are called.
4227 set_program_var(const char *name, const void *value)
4231 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4232 dbg("\"%s\": *%p <-- %p", name, addr, value);
4238 * Search the global objects, including dependencies and main object,
4239 * for the given symbol.
4242 symlook_global(SymLook *req, DoneList *donelist)
4245 const Objlist_Entry *elm;
4248 symlook_init_from_req(&req1, req);
4250 /* Search all objects loaded at program start up. */
4251 if (req->defobj_out == NULL ||
4252 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4253 res = symlook_list(&req1, &list_main, donelist);
4254 if (res == 0 && (req->defobj_out == NULL ||
4255 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4256 req->sym_out = req1.sym_out;
4257 req->defobj_out = req1.defobj_out;
4258 assert(req->defobj_out != NULL);
4262 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4263 STAILQ_FOREACH(elm, &list_global, link) {
4264 if (req->defobj_out != NULL &&
4265 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4267 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4268 if (res == 0 && (req->defobj_out == NULL ||
4269 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4270 req->sym_out = req1.sym_out;
4271 req->defobj_out = req1.defobj_out;
4272 assert(req->defobj_out != NULL);
4276 return (req->sym_out != NULL ? 0 : ESRCH);
4280 * Given a symbol name in a referencing object, find the corresponding
4281 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4282 * no definition was found. Returns a pointer to the Obj_Entry of the
4283 * defining object via the reference parameter DEFOBJ_OUT.
4286 symlook_default(SymLook *req, const Obj_Entry *refobj)
4289 const Objlist_Entry *elm;
4293 donelist_init(&donelist);
4294 symlook_init_from_req(&req1, req);
4297 * Look first in the referencing object if linked symbolically,
4298 * and similarly handle protected symbols.
4300 res = symlook_obj(&req1, refobj);
4301 if (res == 0 && (refobj->symbolic ||
4302 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4303 req->sym_out = req1.sym_out;
4304 req->defobj_out = req1.defobj_out;
4305 assert(req->defobj_out != NULL);
4307 if (refobj->symbolic || req->defobj_out != NULL)
4308 donelist_check(&donelist, refobj);
4310 symlook_global(req, &donelist);
4312 /* Search all dlopened DAGs containing the referencing object. */
4313 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4314 if (req->sym_out != NULL &&
4315 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4317 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4318 if (res == 0 && (req->sym_out == NULL ||
4319 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4320 req->sym_out = req1.sym_out;
4321 req->defobj_out = req1.defobj_out;
4322 assert(req->defobj_out != NULL);
4327 * Search the dynamic linker itself, and possibly resolve the
4328 * symbol from there. This is how the application links to
4329 * dynamic linker services such as dlopen.
4331 if (req->sym_out == NULL ||
4332 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4333 res = symlook_obj(&req1, &obj_rtld);
4335 req->sym_out = req1.sym_out;
4336 req->defobj_out = req1.defobj_out;
4337 assert(req->defobj_out != NULL);
4341 return (req->sym_out != NULL ? 0 : ESRCH);
4345 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4348 const Obj_Entry *defobj;
4349 const Objlist_Entry *elm;
4355 STAILQ_FOREACH(elm, objlist, link) {
4356 if (donelist_check(dlp, elm->obj))
4358 symlook_init_from_req(&req1, req);
4359 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4360 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4362 defobj = req1.defobj_out;
4363 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4370 req->defobj_out = defobj;
4377 * Search the chain of DAGS cointed to by the given Needed_Entry
4378 * for a symbol of the given name. Each DAG is scanned completely
4379 * before advancing to the next one. Returns a pointer to the symbol,
4380 * or NULL if no definition was found.
4383 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4386 const Needed_Entry *n;
4387 const Obj_Entry *defobj;
4393 symlook_init_from_req(&req1, req);
4394 for (n = needed; n != NULL; n = n->next) {
4395 if (n->obj == NULL ||
4396 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 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)
4407 req->defobj_out = defobj;
4414 * Search the symbol table of a single shared object for a symbol of
4415 * the given name and version, if requested. Returns a pointer to the
4416 * symbol, or NULL if no definition was found. If the object is
4417 * filter, return filtered symbol from filtee.
4419 * The symbol's hash value is passed in for efficiency reasons; that
4420 * eliminates many recomputations of the hash value.
4423 symlook_obj(SymLook *req, const Obj_Entry *obj)
4427 int flags, res, mres;
4430 * If there is at least one valid hash at this point, we prefer to
4431 * use the faster GNU version if available.
4433 if (obj->valid_hash_gnu)
4434 mres = symlook_obj1_gnu(req, obj);
4435 else if (obj->valid_hash_sysv)
4436 mres = symlook_obj1_sysv(req, obj);
4441 if (obj->needed_filtees != NULL) {
4442 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4443 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4444 donelist_init(&donelist);
4445 symlook_init_from_req(&req1, req);
4446 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4448 req->sym_out = req1.sym_out;
4449 req->defobj_out = req1.defobj_out;
4453 if (obj->needed_aux_filtees != NULL) {
4454 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4455 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4456 donelist_init(&donelist);
4457 symlook_init_from_req(&req1, req);
4458 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4460 req->sym_out = req1.sym_out;
4461 req->defobj_out = req1.defobj_out;
4469 /* Symbol match routine common to both hash functions */
4471 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4472 const unsigned long symnum)
4475 const Elf_Sym *symp;
4478 symp = obj->symtab + symnum;
4479 strp = obj->strtab + symp->st_name;
4481 switch (ELF_ST_TYPE(symp->st_info)) {
4487 if (symp->st_value == 0)
4491 if (symp->st_shndx != SHN_UNDEF)
4494 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4495 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4502 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4505 if (req->ventry == NULL) {
4506 if (obj->versyms != NULL) {
4507 verndx = VER_NDX(obj->versyms[symnum]);
4508 if (verndx > obj->vernum) {
4510 "%s: symbol %s references wrong version %d",
4511 obj->path, obj->strtab + symnum, verndx);
4515 * If we are not called from dlsym (i.e. this
4516 * is a normal relocation from unversioned
4517 * binary), accept the symbol immediately if
4518 * it happens to have first version after this
4519 * shared object became versioned. Otherwise,
4520 * if symbol is versioned and not hidden,
4521 * remember it. If it is the only symbol with
4522 * this name exported by the shared object, it
4523 * will be returned as a match by the calling
4524 * function. If symbol is global (verndx < 2)
4525 * accept it unconditionally.
4527 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4528 verndx == VER_NDX_GIVEN) {
4529 result->sym_out = symp;
4532 else if (verndx >= VER_NDX_GIVEN) {
4533 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4535 if (result->vsymp == NULL)
4536 result->vsymp = symp;
4542 result->sym_out = symp;
4545 if (obj->versyms == NULL) {
4546 if (object_match_name(obj, req->ventry->name)) {
4547 _rtld_error("%s: object %s should provide version %s "
4548 "for symbol %s", obj_rtld.path, obj->path,
4549 req->ventry->name, obj->strtab + symnum);
4553 verndx = VER_NDX(obj->versyms[symnum]);
4554 if (verndx > obj->vernum) {
4555 _rtld_error("%s: symbol %s references wrong version %d",
4556 obj->path, obj->strtab + symnum, verndx);
4559 if (obj->vertab[verndx].hash != req->ventry->hash ||
4560 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4562 * Version does not match. Look if this is a
4563 * global symbol and if it is not hidden. If
4564 * global symbol (verndx < 2) is available,
4565 * use it. Do not return symbol if we are
4566 * called by dlvsym, because dlvsym looks for
4567 * a specific version and default one is not
4568 * what dlvsym wants.
4570 if ((req->flags & SYMLOOK_DLSYM) ||
4571 (verndx >= VER_NDX_GIVEN) ||
4572 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4576 result->sym_out = symp;
4581 * Search for symbol using SysV hash function.
4582 * obj->buckets is known not to be NULL at this point; the test for this was
4583 * performed with the obj->valid_hash_sysv assignment.
4586 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4588 unsigned long symnum;
4589 Sym_Match_Result matchres;
4591 matchres.sym_out = NULL;
4592 matchres.vsymp = NULL;
4593 matchres.vcount = 0;
4595 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4596 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4597 if (symnum >= obj->nchains)
4598 return (ESRCH); /* Bad object */
4600 if (matched_symbol(req, obj, &matchres, symnum)) {
4601 req->sym_out = matchres.sym_out;
4602 req->defobj_out = obj;
4606 if (matchres.vcount == 1) {
4607 req->sym_out = matchres.vsymp;
4608 req->defobj_out = obj;
4614 /* Search for symbol using GNU hash function */
4616 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4618 Elf_Addr bloom_word;
4619 const Elf32_Word *hashval;
4621 Sym_Match_Result matchres;
4622 unsigned int h1, h2;
4623 unsigned long symnum;
4625 matchres.sym_out = NULL;
4626 matchres.vsymp = NULL;
4627 matchres.vcount = 0;
4629 /* Pick right bitmask word from Bloom filter array */
4630 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4631 obj->maskwords_bm_gnu];
4633 /* Calculate modulus word size of gnu hash and its derivative */
4634 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4635 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4637 /* Filter out the "definitely not in set" queries */
4638 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4641 /* Locate hash chain and corresponding value element*/
4642 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4645 hashval = &obj->chain_zero_gnu[bucket];
4647 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4648 symnum = hashval - obj->chain_zero_gnu;
4649 if (matched_symbol(req, obj, &matchres, symnum)) {
4650 req->sym_out = matchres.sym_out;
4651 req->defobj_out = obj;
4655 } while ((*hashval++ & 1) == 0);
4656 if (matchres.vcount == 1) {
4657 req->sym_out = matchres.vsymp;
4658 req->defobj_out = obj;
4665 trace_loaded_objects(Obj_Entry *obj)
4667 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4670 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4673 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4674 fmt1 = "\t%o => %p (%x)\n";
4676 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4677 fmt2 = "\t%o (%x)\n";
4679 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4681 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4682 Needed_Entry *needed;
4683 const char *name, *path;
4688 if (list_containers && obj->needed != NULL)
4689 rtld_printf("%s:\n", obj->path);
4690 for (needed = obj->needed; needed; needed = needed->next) {
4691 if (needed->obj != NULL) {
4692 if (needed->obj->traced && !list_containers)
4694 needed->obj->traced = true;
4695 path = needed->obj->path;
4699 name = obj->strtab + needed->name;
4700 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4702 fmt = is_lib ? fmt1 : fmt2;
4703 while ((c = *fmt++) != '\0') {
4729 rtld_putstr(main_local);
4732 rtld_putstr(obj_main->path);
4739 rtld_printf("%d", sodp->sod_major);
4742 rtld_printf("%d", sodp->sod_minor);
4749 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4762 * Unload a dlopened object and its dependencies from memory and from
4763 * our data structures. It is assumed that the DAG rooted in the
4764 * object has already been unreferenced, and that the object has a
4765 * reference count of 0.
4768 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4770 Obj_Entry marker, *obj, *next;
4772 assert(root->refcount == 0);
4775 * Pass over the DAG removing unreferenced objects from
4776 * appropriate lists.
4778 unlink_object(root);
4780 /* Unmap all objects that are no longer referenced. */
4781 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4782 next = TAILQ_NEXT(obj, next);
4783 if (obj->marker || obj->refcount != 0)
4785 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4786 obj->mapsize, 0, obj->path);
4787 dbg("unloading \"%s\"", obj->path);
4789 * Unlink the object now to prevent new references from
4790 * being acquired while the bind lock is dropped in
4791 * recursive dlclose() invocations.
4793 TAILQ_REMOVE(&obj_list, obj, next);
4796 if (obj->filtees_loaded) {
4798 init_marker(&marker);
4799 TAILQ_INSERT_BEFORE(next, &marker, next);
4800 unload_filtees(obj, lockstate);
4801 next = TAILQ_NEXT(&marker, next);
4802 TAILQ_REMOVE(&obj_list, &marker, next);
4804 unload_filtees(obj, lockstate);
4806 release_object(obj);
4811 unlink_object(Obj_Entry *root)
4815 if (root->refcount == 0) {
4816 /* Remove the object from the RTLD_GLOBAL list. */
4817 objlist_remove(&list_global, root);
4819 /* Remove the object from all objects' DAG lists. */
4820 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4821 objlist_remove(&elm->obj->dldags, root);
4822 if (elm->obj != root)
4823 unlink_object(elm->obj);
4829 ref_dag(Obj_Entry *root)
4833 assert(root->dag_inited);
4834 STAILQ_FOREACH(elm, &root->dagmembers, link)
4835 elm->obj->refcount++;
4839 unref_dag(Obj_Entry *root)
4843 assert(root->dag_inited);
4844 STAILQ_FOREACH(elm, &root->dagmembers, link)
4845 elm->obj->refcount--;
4849 * Common code for MD __tls_get_addr().
4851 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4853 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4855 Elf_Addr *newdtv, *dtv;
4856 RtldLockState lockstate;
4860 /* Check dtv generation in case new modules have arrived */
4861 if (dtv[0] != tls_dtv_generation) {
4862 wlock_acquire(rtld_bind_lock, &lockstate);
4863 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4865 if (to_copy > tls_max_index)
4866 to_copy = tls_max_index;
4867 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4868 newdtv[0] = tls_dtv_generation;
4869 newdtv[1] = tls_max_index;
4871 lock_release(rtld_bind_lock, &lockstate);
4872 dtv = *dtvp = newdtv;
4875 /* Dynamically allocate module TLS if necessary */
4876 if (dtv[index + 1] == 0) {
4877 /* Signal safe, wlock will block out signals. */
4878 wlock_acquire(rtld_bind_lock, &lockstate);
4879 if (!dtv[index + 1])
4880 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4881 lock_release(rtld_bind_lock, &lockstate);
4883 return ((void *)(dtv[index + 1] + offset));
4887 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4892 /* Check dtv generation in case new modules have arrived */
4893 if (__predict_true(dtv[0] == tls_dtv_generation &&
4894 dtv[index + 1] != 0))
4895 return ((void *)(dtv[index + 1] + offset));
4896 return (tls_get_addr_slow(dtvp, index, offset));
4899 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4900 defined(__powerpc__) || defined(__riscv)
4903 * Return pointer to allocated TLS block
4906 get_tls_block_ptr(void *tcb, size_t tcbsize)
4908 size_t extra_size, post_size, pre_size, tls_block_size;
4909 size_t tls_init_align;
4911 tls_init_align = MAX(obj_main->tlsalign, 1);
4913 /* Compute fragments sizes. */
4914 extra_size = tcbsize - TLS_TCB_SIZE;
4915 post_size = calculate_tls_post_size(tls_init_align);
4916 tls_block_size = tcbsize + post_size;
4917 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4919 return ((char *)tcb - pre_size - extra_size);
4923 * Allocate Static TLS using the Variant I method.
4925 * For details on the layout, see lib/libc/gen/tls.c.
4927 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4928 * it is based on tls_last_offset, and TLS offsets here are really TCB
4929 * offsets, whereas libc's tls_static_space is just the executable's static
4933 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4937 Elf_Addr *dtv, **tcb;
4940 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4941 size_t tls_init_align, tls_init_offset;
4943 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4946 assert(tcbsize >= TLS_TCB_SIZE);
4947 maxalign = MAX(tcbalign, tls_static_max_align);
4948 tls_init_align = MAX(obj_main->tlsalign, 1);
4950 /* Compute fragmets sizes. */
4951 extra_size = tcbsize - TLS_TCB_SIZE;
4952 post_size = calculate_tls_post_size(tls_init_align);
4953 tls_block_size = tcbsize + post_size;
4954 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4955 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4957 /* Allocate whole TLS block */
4958 tls_block = malloc_aligned(tls_block_size, maxalign, 0);
4959 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4961 if (oldtcb != NULL) {
4962 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4964 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4966 /* Adjust the DTV. */
4968 for (i = 0; i < dtv[1]; i++) {
4969 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4970 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4971 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4975 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4977 dtv[0] = tls_dtv_generation;
4978 dtv[1] = tls_max_index;
4980 for (obj = globallist_curr(objs); obj != NULL;
4981 obj = globallist_next(obj)) {
4982 if (obj->tlsoffset == 0)
4984 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
4985 addr = (Elf_Addr)tcb + obj->tlsoffset;
4986 if (tls_init_offset > 0)
4987 memset((void *)addr, 0, tls_init_offset);
4988 if (obj->tlsinitsize > 0) {
4989 memcpy((void *)(addr + tls_init_offset), obj->tlsinit,
4992 if (obj->tlssize > obj->tlsinitsize) {
4993 memset((void *)(addr + tls_init_offset + obj->tlsinitsize),
4994 0, obj->tlssize - obj->tlsinitsize - tls_init_offset);
4996 dtv[obj->tlsindex + 1] = addr;
5004 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
5007 Elf_Addr tlsstart, tlsend;
5009 size_t dtvsize, i, tls_init_align;
5011 assert(tcbsize >= TLS_TCB_SIZE);
5012 tls_init_align = MAX(obj_main->tlsalign, 1);
5014 /* Compute fragments sizes. */
5015 post_size = calculate_tls_post_size(tls_init_align);
5017 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
5018 tlsend = (Elf_Addr)tcb + tls_static_space;
5020 dtv = *(Elf_Addr **)tcb;
5022 for (i = 0; i < dtvsize; i++) {
5023 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
5024 free((void*)dtv[i+2]);
5028 free_aligned(get_tls_block_ptr(tcb, tcbsize));
5033 #if defined(__i386__) || defined(__amd64__)
5036 * Allocate Static TLS using the Variant II method.
5039 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
5042 size_t size, ralign;
5044 Elf_Addr *dtv, *olddtv;
5045 Elf_Addr segbase, oldsegbase, addr;
5049 if (tls_static_max_align > ralign)
5050 ralign = tls_static_max_align;
5051 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
5053 assert(tcbsize >= 2*sizeof(Elf_Addr));
5054 tls = malloc_aligned(size, ralign, 0 /* XXX */);
5055 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
5057 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign));
5058 ((Elf_Addr*)segbase)[0] = segbase;
5059 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
5061 dtv[0] = tls_dtv_generation;
5062 dtv[1] = tls_max_index;
5066 * Copy the static TLS block over whole.
5068 oldsegbase = (Elf_Addr) oldtls;
5069 memcpy((void *)(segbase - tls_static_space),
5070 (const void *)(oldsegbase - tls_static_space),
5074 * If any dynamic TLS blocks have been created tls_get_addr(),
5077 olddtv = ((Elf_Addr**)oldsegbase)[1];
5078 for (i = 0; i < olddtv[1]; i++) {
5079 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
5080 dtv[i+2] = olddtv[i+2];
5086 * We assume that this block was the one we created with
5087 * allocate_initial_tls().
5089 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
5091 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
5092 if (obj->marker || obj->tlsoffset == 0)
5094 addr = segbase - obj->tlsoffset;
5095 memset((void*)(addr + obj->tlsinitsize),
5096 0, obj->tlssize - obj->tlsinitsize);
5098 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
5099 obj->static_tls_copied = true;
5101 dtv[obj->tlsindex + 1] = addr;
5105 return (void*) segbase;
5109 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
5112 size_t size, ralign;
5114 Elf_Addr tlsstart, tlsend;
5117 * Figure out the size of the initial TLS block so that we can
5118 * find stuff which ___tls_get_addr() allocated dynamically.
5121 if (tls_static_max_align > ralign)
5122 ralign = tls_static_max_align;
5123 size = roundup(tls_static_space, ralign);
5125 dtv = ((Elf_Addr**)tls)[1];
5127 tlsend = (Elf_Addr) tls;
5128 tlsstart = tlsend - size;
5129 for (i = 0; i < dtvsize; i++) {
5130 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
5131 free_aligned((void *)dtv[i + 2]);
5135 free_aligned((void *)tlsstart);
5142 * Allocate TLS block for module with given index.
5145 allocate_module_tls(int index)
5150 TAILQ_FOREACH(obj, &obj_list, next) {
5153 if (obj->tlsindex == index)
5157 _rtld_error("Can't find module with TLS index %d", index);
5161 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5162 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5163 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5168 allocate_tls_offset(Obj_Entry *obj)
5175 if (obj->tlssize == 0) {
5176 obj->tls_done = true;
5180 if (tls_last_offset == 0)
5181 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign,
5184 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5185 obj->tlssize, obj->tlsalign, obj->tlspoffset);
5188 * If we have already fixed the size of the static TLS block, we
5189 * must stay within that size. When allocating the static TLS, we
5190 * leave a small amount of space spare to be used for dynamically
5191 * loading modules which use static TLS.
5193 if (tls_static_space != 0) {
5194 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5196 } else if (obj->tlsalign > tls_static_max_align) {
5197 tls_static_max_align = obj->tlsalign;
5200 tls_last_offset = obj->tlsoffset = off;
5201 tls_last_size = obj->tlssize;
5202 obj->tls_done = true;
5208 free_tls_offset(Obj_Entry *obj)
5212 * If we were the last thing to allocate out of the static TLS
5213 * block, we give our space back to the 'allocator'. This is a
5214 * simplistic workaround to allow libGL.so.1 to be loaded and
5215 * unloaded multiple times.
5217 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5218 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5219 tls_last_offset -= obj->tlssize;
5225 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5228 RtldLockState lockstate;
5230 wlock_acquire(rtld_bind_lock, &lockstate);
5231 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5233 lock_release(rtld_bind_lock, &lockstate);
5238 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5240 RtldLockState lockstate;
5242 wlock_acquire(rtld_bind_lock, &lockstate);
5243 free_tls(tcb, tcbsize, tcbalign);
5244 lock_release(rtld_bind_lock, &lockstate);
5248 object_add_name(Obj_Entry *obj, const char *name)
5254 entry = malloc(sizeof(Name_Entry) + len);
5256 if (entry != NULL) {
5257 strcpy(entry->name, name);
5258 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5263 object_match_name(const Obj_Entry *obj, const char *name)
5267 STAILQ_FOREACH(entry, &obj->names, link) {
5268 if (strcmp(name, entry->name) == 0)
5275 locate_dependency(const Obj_Entry *obj, const char *name)
5277 const Objlist_Entry *entry;
5278 const Needed_Entry *needed;
5280 STAILQ_FOREACH(entry, &list_main, link) {
5281 if (object_match_name(entry->obj, name))
5285 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5286 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5287 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5289 * If there is DT_NEEDED for the name we are looking for,
5290 * we are all set. Note that object might not be found if
5291 * dependency was not loaded yet, so the function can
5292 * return NULL here. This is expected and handled
5293 * properly by the caller.
5295 return (needed->obj);
5298 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5304 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5305 const Elf_Vernaux *vna)
5307 const Elf_Verdef *vd;
5308 const char *vername;
5310 vername = refobj->strtab + vna->vna_name;
5311 vd = depobj->verdef;
5313 _rtld_error("%s: version %s required by %s not defined",
5314 depobj->path, vername, refobj->path);
5318 if (vd->vd_version != VER_DEF_CURRENT) {
5319 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5320 depobj->path, vd->vd_version);
5323 if (vna->vna_hash == vd->vd_hash) {
5324 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5325 ((const char *)vd + vd->vd_aux);
5326 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5329 if (vd->vd_next == 0)
5331 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5333 if (vna->vna_flags & VER_FLG_WEAK)
5335 _rtld_error("%s: version %s required by %s not found",
5336 depobj->path, vername, refobj->path);
5341 rtld_verify_object_versions(Obj_Entry *obj)
5343 const Elf_Verneed *vn;
5344 const Elf_Verdef *vd;
5345 const Elf_Verdaux *vda;
5346 const Elf_Vernaux *vna;
5347 const Obj_Entry *depobj;
5348 int maxvernum, vernum;
5350 if (obj->ver_checked)
5352 obj->ver_checked = true;
5356 * Walk over defined and required version records and figure out
5357 * max index used by any of them. Do very basic sanity checking
5361 while (vn != NULL) {
5362 if (vn->vn_version != VER_NEED_CURRENT) {
5363 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5364 obj->path, vn->vn_version);
5367 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5369 vernum = VER_NEED_IDX(vna->vna_other);
5370 if (vernum > maxvernum)
5372 if (vna->vna_next == 0)
5374 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5376 if (vn->vn_next == 0)
5378 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5382 while (vd != NULL) {
5383 if (vd->vd_version != VER_DEF_CURRENT) {
5384 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5385 obj->path, vd->vd_version);
5388 vernum = VER_DEF_IDX(vd->vd_ndx);
5389 if (vernum > maxvernum)
5391 if (vd->vd_next == 0)
5393 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5400 * Store version information in array indexable by version index.
5401 * Verify that object version requirements are satisfied along the
5404 obj->vernum = maxvernum + 1;
5405 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5408 while (vd != NULL) {
5409 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5410 vernum = VER_DEF_IDX(vd->vd_ndx);
5411 assert(vernum <= maxvernum);
5412 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5413 obj->vertab[vernum].hash = vd->vd_hash;
5414 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5415 obj->vertab[vernum].file = NULL;
5416 obj->vertab[vernum].flags = 0;
5418 if (vd->vd_next == 0)
5420 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5424 while (vn != NULL) {
5425 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5428 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5430 if (check_object_provided_version(obj, depobj, vna))
5432 vernum = VER_NEED_IDX(vna->vna_other);
5433 assert(vernum <= maxvernum);
5434 obj->vertab[vernum].hash = vna->vna_hash;
5435 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5436 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5437 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5438 VER_INFO_HIDDEN : 0;
5439 if (vna->vna_next == 0)
5441 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5443 if (vn->vn_next == 0)
5445 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5451 rtld_verify_versions(const Objlist *objlist)
5453 Objlist_Entry *entry;
5457 STAILQ_FOREACH(entry, objlist, link) {
5459 * Skip dummy objects or objects that have their version requirements
5462 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5464 if (rtld_verify_object_versions(entry->obj) == -1) {
5466 if (ld_tracing == NULL)
5470 if (rc == 0 || ld_tracing != NULL)
5471 rc = rtld_verify_object_versions(&obj_rtld);
5476 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5481 vernum = VER_NDX(obj->versyms[symnum]);
5482 if (vernum >= obj->vernum) {
5483 _rtld_error("%s: symbol %s has wrong verneed value %d",
5484 obj->path, obj->strtab + symnum, vernum);
5485 } else if (obj->vertab[vernum].hash != 0) {
5486 return &obj->vertab[vernum];
5493 _rtld_get_stack_prot(void)
5496 return (stack_prot);
5500 _rtld_is_dlopened(void *arg)
5503 RtldLockState lockstate;
5506 rlock_acquire(rtld_bind_lock, &lockstate);
5509 obj = obj_from_addr(arg);
5511 _rtld_error("No shared object contains address");
5512 lock_release(rtld_bind_lock, &lockstate);
5515 res = obj->dlopened ? 1 : 0;
5516 lock_release(rtld_bind_lock, &lockstate);
5521 obj_remap_relro(Obj_Entry *obj, int prot)
5524 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5526 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5527 obj->path, prot, rtld_strerror(errno));
5534 obj_disable_relro(Obj_Entry *obj)
5537 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5541 obj_enforce_relro(Obj_Entry *obj)
5544 return (obj_remap_relro(obj, PROT_READ));
5548 map_stacks_exec(RtldLockState *lockstate)
5550 void (*thr_map_stacks_exec)(void);
5552 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5554 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5555 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5556 if (thr_map_stacks_exec != NULL) {
5557 stack_prot |= PROT_EXEC;
5558 thr_map_stacks_exec();
5563 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5567 void (*distrib)(size_t, void *, size_t, size_t);
5569 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5570 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5571 if (distrib == NULL)
5573 STAILQ_FOREACH(elm, list, link) {
5575 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5577 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5579 obj->static_tls_copied = true;
5584 symlook_init(SymLook *dst, const char *name)
5587 bzero(dst, sizeof(*dst));
5589 dst->hash = elf_hash(name);
5590 dst->hash_gnu = gnu_hash(name);
5594 symlook_init_from_req(SymLook *dst, const SymLook *src)
5597 dst->name = src->name;
5598 dst->hash = src->hash;
5599 dst->hash_gnu = src->hash_gnu;
5600 dst->ventry = src->ventry;
5601 dst->flags = src->flags;
5602 dst->defobj_out = NULL;
5603 dst->sym_out = NULL;
5604 dst->lockstate = src->lockstate;
5608 open_binary_fd(const char *argv0, bool search_in_path,
5609 const char **binpath_res)
5611 char *binpath, *pathenv, *pe, *res1;
5617 if (search_in_path && strchr(argv0, '/') == NULL) {
5618 binpath = xmalloc(PATH_MAX);
5619 pathenv = getenv("PATH");
5620 if (pathenv == NULL) {
5621 _rtld_error("-p and no PATH environment variable");
5624 pathenv = strdup(pathenv);
5625 if (pathenv == NULL) {
5626 _rtld_error("Cannot allocate memory");
5631 while ((pe = strsep(&pathenv, ":")) != NULL) {
5632 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
5634 if (binpath[0] != '\0' &&
5635 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
5637 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
5639 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5640 if (fd != -1 || errno != ENOENT) {
5647 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5652 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5655 if (res != NULL && res[0] != '/') {
5656 res1 = xmalloc(PATH_MAX);
5657 if (realpath(res, res1) != NULL) {
5659 free(__DECONST(char *, res));
5670 * Parse a set of command-line arguments.
5673 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
5679 int arglen, fd, i, j, mib[2];
5681 bool seen_b, seen_f;
5683 dbg("Parsing command-line arguments");
5686 seen_b = seen_f = false;
5688 for (i = 1; i < argc; i++ ) {
5690 dbg("argv[%d]: '%s'", i, arg);
5693 * rtld arguments end with an explicit "--" or with the first
5694 * non-prefixed argument.
5696 if (strcmp(arg, "--") == 0) {
5704 * All other arguments are single-character options that can
5705 * be combined, so we need to search through `arg` for them.
5707 arglen = strlen(arg);
5708 for (j = 1; j < arglen; j++) {
5711 print_usage(argv[0]);
5713 } else if (opt == 'b') {
5715 _rtld_error("Both -b and -f specified");
5722 } else if (opt == 'f') {
5724 _rtld_error("Both -b and -f specified");
5729 * -f XX can be used to specify a
5730 * descriptor for the binary named at
5731 * the command line (i.e., the later
5732 * argument will specify the process
5733 * name but the descriptor is what
5734 * will actually be executed).
5736 * -f must be the last option in, e.g., -abcf.
5738 if (j != arglen - 1) {
5739 _rtld_error("Invalid options: %s", arg);
5743 fd = parse_integer(argv[i]);
5746 "Invalid file descriptor: '%s'",
5753 } else if (opt == 'p') {
5755 } else if (opt == 'v') {
5758 mib[1] = HW_MACHINE;
5759 sz = sizeof(machine);
5760 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
5762 "FreeBSD ld-elf.so.1 %s\n"
5763 "FreeBSD_version %d\n"
5764 "Default lib path %s\n"
5769 __FreeBSD_version, ld_standard_library_path,
5770 ld_env_prefix, ld_elf_hints_default,
5771 ld_path_libmap_conf);
5774 _rtld_error("Invalid argument: '%s'", arg);
5775 print_usage(argv[0]);
5787 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5790 parse_integer(const char *str)
5792 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5799 for (c = *str; c != '\0'; c = *++str) {
5800 if (c < '0' || c > '9')
5807 /* Make sure we actually parsed something. */
5814 print_usage(const char *argv0)
5818 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n"
5821 " -h Display this help message\n"
5822 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
5823 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5824 " -p Search in PATH for named binary\n"
5825 " -v Display identification information\n"
5826 " -- End of RTLD options\n"
5827 " <binary> Name of process to execute\n"
5828 " <args> Arguments to the executed process\n", argv0);
5832 * Overrides for libc_pic-provided functions.
5836 __getosreldate(void)
5846 oid[1] = KERN_OSRELDATE;
5848 len = sizeof(osrel);
5849 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5850 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5855 rtld_strerror(int errnum)
5858 if (errnum < 0 || errnum >= sys_nerr)
5859 return ("Unknown error");
5860 return (sys_errlist[errnum]);
5865 malloc(size_t nbytes)
5868 return (__crt_malloc(nbytes));
5872 calloc(size_t num, size_t size)
5875 return (__crt_calloc(num, size));
5886 realloc(void *cp, size_t nbytes)
5889 return (__crt_realloc(cp, nbytes));
5892 extern int _rtld_version__FreeBSD_version __exported;
5893 int _rtld_version__FreeBSD_version = __FreeBSD_version;
5895 extern char _rtld_version_laddr_offset __exported;
5896 char _rtld_version_laddr_offset;