2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 * $FreeBSD: src/libexec/rtld-elf/rtld.c,v 1.173 2011/02/09 09:20:27 kib Exp $
31 * Dynamic linker for ELF.
33 * John Polstra <jdp@polstra.com>.
37 #error "GCC is needed to compile this file"
40 #include <sys/param.h>
41 #include <sys/mount.h>
45 #include <sys/utsname.h>
46 #include <sys/ktrace.h>
47 #include <sys/resident.h>
50 #include <machine/tls.h>
66 #define PATH_RTLD "/usr/libexec/ld-elf.so.2"
67 #define LD_ARY_CACHE 16
70 typedef void (*func_ptr_type)();
71 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
74 * This structure provides a reentrant way to keep a list of objects and
75 * check which ones have already been processed in some way.
77 typedef struct Struct_DoneList {
78 const Obj_Entry **objs; /* Array of object pointers */
79 unsigned int num_alloc; /* Allocated size of the array */
80 unsigned int num_used; /* Number of array slots used */
84 * Function declarations.
86 static const char *_getenv_ld(const char *id);
87 static void die(void) __dead2;
88 static void digest_dynamic(Obj_Entry *, int);
89 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
90 static Obj_Entry *dlcheck(void *);
91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
93 static bool donelist_check(DoneList *, const Obj_Entry *);
94 static void errmsg_restore(char *);
95 static char *errmsg_save(void);
96 static void *fill_search_info(const char *, size_t, void *);
97 static char *find_library(const char *, const Obj_Entry *);
98 static const char *gethints(void);
99 static void init_dag(Obj_Entry *);
100 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *);
101 static void init_rtld(caddr_t);
102 static void initlist_add_neededs(Needed_Entry *, Objlist *);
103 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
104 static bool is_exported(const Elf_Sym *);
105 static void linkmap_add(Obj_Entry *);
106 static void linkmap_delete(Obj_Entry *);
107 static int load_needed_objects(Obj_Entry *, int);
108 static int load_preload_objects(void);
109 static Obj_Entry *load_object(const char *, const Obj_Entry *, int);
110 static Obj_Entry *obj_from_addr(const void *);
111 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
112 static void objlist_call_init(Objlist *, RtldLockState *);
113 static void objlist_clear(Objlist *);
114 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
115 static void objlist_init(Objlist *);
116 static void objlist_push_head(Objlist *, Obj_Entry *);
117 static void objlist_push_tail(Objlist *, Obj_Entry *);
118 static void objlist_remove(Objlist *, Obj_Entry *);
119 static void *path_enumerate(const char *, path_enum_proc, void *);
120 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *);
121 static int rtld_dirname(const char *, char *);
122 static int rtld_dirname_abs(const char *, char *);
123 static void rtld_exit(void);
124 static char *search_library_path(const char *, const char *);
125 static const void **get_program_var_addr(const char *);
126 static void set_program_var(const char *, const void *);
127 static const Elf_Sym *symlook_default(const char *, unsigned long,
128 const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int);
129 static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *,
130 const Obj_Entry **, const Ver_Entry *, int, DoneList *);
131 static const Elf_Sym *symlook_needed(const char *, unsigned long,
132 const Needed_Entry *, const Obj_Entry **, const Ver_Entry *,
134 static void trace_loaded_objects(Obj_Entry *);
135 static void unlink_object(Obj_Entry *);
136 static void unload_object(Obj_Entry *);
137 static void unref_dag(Obj_Entry *);
138 static void ref_dag(Obj_Entry *);
139 static int origin_subst_one(char **, const char *, const char *,
140 const char *, char *);
141 static char *origin_subst(const char *, const char *);
142 static int rtld_verify_versions(const Objlist *);
143 static int rtld_verify_object_versions(Obj_Entry *);
144 static void object_add_name(Obj_Entry *, const char *);
145 static int object_match_name(const Obj_Entry *, const char *);
146 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
147 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
148 struct dl_phdr_info *phdr_info);
150 void r_debug_state(struct r_debug *, struct link_map *);
155 static char *error_message; /* Message for dlerror(), or NULL */
156 struct r_debug r_debug; /* for GDB; */
157 static bool libmap_disable; /* Disable libmap */
158 static char *libmap_override; /* Maps to use in addition to libmap.conf */
159 static bool trust; /* False for setuid and setgid programs */
160 static bool dangerous_ld_env; /* True if environment variables have been
161 used to affect the libraries loaded */
162 static const char *ld_bind_now; /* Environment variable for immediate binding */
163 static const char *ld_debug; /* Environment variable for debugging */
164 static const char *ld_library_path; /* Environment variable for search path */
165 static char *ld_preload; /* Environment variable for libraries to
167 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
168 static const char *ld_tracing; /* Called from ldd(1) to print libs */
169 /* Optional function call tracing hook */
170 static const char *ld_utrace; /* Use utrace() to log events. */
171 static int (*rtld_functrace)(const char *caller_obj,
172 const char *callee_obj,
173 const char *callee_func,
175 static Obj_Entry *rtld_functrace_obj; /* Object thereof */
176 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
177 static Obj_Entry **obj_tail; /* Link field of last object in list */
178 static Obj_Entry **preload_tail;
179 static Obj_Entry *obj_main; /* The main program shared object */
180 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
181 static unsigned int obj_count; /* Number of objects in obj_list */
182 static unsigned int obj_loads; /* Number of objects in obj_list */
184 static int ld_resident; /* Non-zero if resident */
185 static const char *ld_ary[LD_ARY_CACHE];
187 static Objlist initlist;
189 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
190 STAILQ_HEAD_INITIALIZER(list_global);
191 static Objlist list_main = /* Objects loaded at program startup */
192 STAILQ_HEAD_INITIALIZER(list_main);
193 static Objlist list_fini = /* Objects needing fini() calls */
194 STAILQ_HEAD_INITIALIZER(list_fini);
196 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
198 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
200 extern Elf_Dyn _DYNAMIC;
201 #pragma weak _DYNAMIC
202 #ifndef RTLD_IS_DYNAMIC
203 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
207 * These are the functions the dynamic linker exports to application
208 * programs. They are the only symbols the dynamic linker is willing
209 * to export from itself.
211 static func_ptr_type exports[] = {
212 (func_ptr_type) &_rtld_error,
213 (func_ptr_type) &dlclose,
214 (func_ptr_type) &dlerror,
215 (func_ptr_type) &dlopen,
216 (func_ptr_type) &dlfunc,
217 (func_ptr_type) &dlsym,
218 (func_ptr_type) &dlvsym,
219 (func_ptr_type) &dladdr,
220 (func_ptr_type) &dlinfo,
221 (func_ptr_type) &dl_iterate_phdr,
223 (func_ptr_type) &___tls_get_addr,
225 (func_ptr_type) &__tls_get_addr,
226 (func_ptr_type) &__tls_get_addr_tcb,
227 (func_ptr_type) &_rtld_allocate_tls,
228 (func_ptr_type) &_rtld_free_tls,
229 (func_ptr_type) &_rtld_call_init,
230 (func_ptr_type) &_rtld_thread_init,
231 (func_ptr_type) &_rtld_addr_phdr,
236 * Global declarations normally provided by crt1. The dynamic linker is
237 * not built with crt1, so we have to provide them ourselves.
243 * Globals to control TLS allocation.
245 size_t tls_last_offset; /* Static TLS offset of last module */
246 size_t tls_last_size; /* Static TLS size of last module */
247 size_t tls_static_space; /* Static TLS space allocated */
248 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
249 int tls_max_index = 1; /* Largest module index allocated */
252 * Fill in a DoneList with an allocation large enough to hold all of
253 * the currently-loaded objects. Keep this as a macro since it calls
254 * alloca and we want that to occur within the scope of the caller.
256 #define donelist_init(dlp) \
257 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
258 assert((dlp)->objs != NULL), \
259 (dlp)->num_alloc = obj_count, \
262 #define UTRACE_DLOPEN_START 1
263 #define UTRACE_DLOPEN_STOP 2
264 #define UTRACE_DLCLOSE_START 3
265 #define UTRACE_DLCLOSE_STOP 4
266 #define UTRACE_LOAD_OBJECT 5
267 #define UTRACE_UNLOAD_OBJECT 6
268 #define UTRACE_ADD_RUNDEP 7
269 #define UTRACE_PRELOAD_FINISHED 8
270 #define UTRACE_INIT_CALL 9
271 #define UTRACE_FINI_CALL 10
274 char sig[4]; /* 'RTLD' */
277 void *mapbase; /* Used for 'parent' and 'init/fini' */
279 int refcnt; /* Used for 'mode' */
280 char name[MAXPATHLEN];
283 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
284 if (ld_utrace != NULL) \
285 ld_utrace_log(e, h, mb, ms, r, n); \
289 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
290 int refcnt, const char *name)
292 struct utrace_rtld ut;
300 ut.mapbase = mapbase;
301 ut.mapsize = mapsize;
303 bzero(ut.name, sizeof(ut.name));
305 strlcpy(ut.name, name, sizeof(ut.name));
306 utrace(&ut, sizeof(ut));
310 * Main entry point for dynamic linking. The first argument is the
311 * stack pointer. The stack is expected to be laid out as described
312 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
313 * Specifically, the stack pointer points to a word containing
314 * ARGC. Following that in the stack is a null-terminated sequence
315 * of pointers to argument strings. Then comes a null-terminated
316 * sequence of pointers to environment strings. Finally, there is a
317 * sequence of "auxiliary vector" entries.
319 * The second argument points to a place to store the dynamic linker's
320 * exit procedure pointer and the third to a place to store the main
323 * The return value is the main program's entry point.
326 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
328 Elf_Auxinfo *aux_info[AT_COUNT];
336 Objlist_Entry *entry;
339 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld
340 Obj_Entry **preload_tail;
342 from global to here. It will break the DRAWF2 unwind scheme.
343 The system compilers were unaffected, but not gcc 4.6
347 * On entry, the dynamic linker itself has not been relocated yet.
348 * Be very careful not to reference any global data until after
349 * init_rtld has returned. It is OK to reference file-scope statics
350 * and string constants, and to call static and global functions.
353 /* Find the auxiliary vector on the stack. */
356 sp += argc + 1; /* Skip over arguments and NULL terminator */
360 * If we aren't already resident we have to dig out some more info.
361 * Note that auxinfo does not exist when we are resident.
363 * I'm not sure about the ld_resident check. It seems to read zero
364 * prior to relocation, which is what we want. When running from a
365 * resident copy everything will be relocated so we are definitely
368 if (ld_resident == 0) {
369 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
371 aux = (Elf_Auxinfo *) sp;
373 /* Digest the auxiliary vector. */
374 for (i = 0; i < AT_COUNT; i++)
376 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
377 if (auxp->a_type < AT_COUNT)
378 aux_info[auxp->a_type] = auxp;
381 /* Initialize and relocate ourselves. */
382 assert(aux_info[AT_BASE] != NULL);
383 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
386 ld_index = 0; /* don't use old env cache in case we are resident */
387 __progname = obj_rtld.path;
388 argv0 = argv[0] != NULL ? argv[0] : "(null)";
391 trust = !issetugid();
393 ld_bind_now = _getenv_ld("LD_BIND_NOW");
395 * If the process is tainted, then we un-set the dangerous environment
396 * variables. The process will be marked as tainted until setuid(2)
397 * is called. If any child process calls setuid(2) we do not want any
398 * future processes to honor the potentially un-safe variables.
401 if ( unsetenv("LD_DEBUG")
402 || unsetenv("LD_PRELOAD")
403 || unsetenv("LD_LIBRARY_PATH")
404 || unsetenv("LD_ELF_HINTS_PATH")
405 || unsetenv("LD_LIBMAP")
406 || unsetenv("LD_LIBMAP_DISABLE")
408 _rtld_error("environment corrupt; aborting");
412 ld_debug = _getenv_ld("LD_DEBUG");
413 ld_library_path = _getenv_ld("LD_LIBRARY_PATH");
414 ld_preload = (char *)_getenv_ld("LD_PRELOAD");
415 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH");
416 libmap_override = (char *)_getenv_ld("LD_LIBMAP");
417 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL;
418 dangerous_ld_env = (ld_library_path != NULL)
419 || (ld_preload != NULL)
420 || (ld_elf_hints_path != NULL)
421 || (libmap_override != NULL)
424 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS");
425 ld_utrace = _getenv_ld("LD_UTRACE");
427 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
428 ld_elf_hints_path = _PATH_ELF_HINTS;
430 if (ld_debug != NULL && *ld_debug != '\0')
432 dbg("%s is initialized, base address = %p", __progname,
433 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
434 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
435 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
437 dbg("initializing thread locks");
441 * If we are resident we can skip work that we have already done.
442 * Note that the stack is reset and there is no Elf_Auxinfo
443 * when running from a resident image, and the static globals setup
444 * between here and resident_skip will have already been setup.
450 * Load the main program, or process its program header if it is
453 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
454 int fd = aux_info[AT_EXECFD]->a_un.a_val;
455 dbg("loading main program");
456 obj_main = map_object(fd, argv0, NULL);
458 if (obj_main == NULL)
460 } else { /* Main program already loaded. */
461 const Elf_Phdr *phdr;
465 dbg("processing main program's program header");
466 assert(aux_info[AT_PHDR] != NULL);
467 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
468 assert(aux_info[AT_PHNUM] != NULL);
469 phnum = aux_info[AT_PHNUM]->a_un.a_val;
470 assert(aux_info[AT_PHENT] != NULL);
471 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
472 assert(aux_info[AT_ENTRY] != NULL);
473 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
474 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
478 char buf[MAXPATHLEN];
479 if (aux_info[AT_EXECPATH] != 0) {
482 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
483 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
484 if (kexecpath[0] == '/')
485 obj_main->path = kexecpath;
486 else if (getcwd(buf, sizeof(buf)) == NULL ||
487 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
488 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
489 obj_main->path = xstrdup(argv0);
491 obj_main->path = xstrdup(buf);
493 char resolved[MAXPATHLEN];
494 dbg("No AT_EXECPATH");
495 if (argv0[0] == '/') {
496 if (realpath(argv0, resolved) != NULL)
497 obj_main->path = xstrdup(resolved);
499 obj_main->path = xstrdup(argv0);
501 if (getcwd(buf, sizeof(buf)) != NULL
502 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf)
503 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf)
504 && access(buf, R_OK) == 0
505 && realpath(buf, resolved) != NULL)
506 obj_main->path = xstrdup(resolved);
508 obj_main->path = xstrdup(argv0);
511 dbg("obj_main path %s", obj_main->path);
512 obj_main->mainprog = true;
515 * Get the actual dynamic linker pathname from the executable if
516 * possible. (It should always be possible.) That ensures that
517 * gdb will find the right dynamic linker even if a non-standard
520 if (obj_main->interp != NULL &&
521 strcmp(obj_main->interp, obj_rtld.path) != 0) {
523 obj_rtld.path = xstrdup(obj_main->interp);
524 __progname = obj_rtld.path;
527 digest_dynamic(obj_main, 0);
529 linkmap_add(obj_main);
530 linkmap_add(&obj_rtld);
532 /* Link the main program into the list of objects. */
533 *obj_tail = obj_main;
534 obj_tail = &obj_main->next;
537 /* Make sure we don't call the main program's init and fini functions. */
538 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
540 /* Initialize a fake symbol for resolving undefined weak references. */
541 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
542 sym_zero.st_shndx = SHN_UNDEF;
543 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
546 libmap_disable = (bool)lm_init(libmap_override);
548 dbg("loading LD_PRELOAD libraries");
549 if (load_preload_objects() == -1)
551 preload_tail = obj_tail;
553 dbg("loading needed objects");
554 if (load_needed_objects(obj_main, 0) == -1)
557 /* Make a list of all objects loaded at startup. */
558 for (obj = obj_list; obj != NULL; obj = obj->next) {
559 objlist_push_tail(&list_main, obj);
563 dbg("checking for required versions");
564 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
569 if (ld_tracing) { /* We're done */
570 trace_loaded_objects(obj_main);
574 if (ld_resident) /* XXX clean this up! */
577 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) {
578 dump_relocations(obj_main);
582 /* setup TLS for main thread */
583 dbg("initializing initial thread local storage");
584 STAILQ_FOREACH(entry, &list_main, link) {
586 * Allocate all the initial objects out of the static TLS
587 * block even if they didn't ask for it.
589 allocate_tls_offset(entry->obj);
592 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
595 * Do not try to allocate the TLS here, let libc do it itself.
596 * (crt1 for the program will call _init_tls())
599 if (relocate_objects(obj_main,
600 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld) == -1)
603 dbg("doing copy relocations");
604 if (do_copy_relocations(obj_main) == -1)
609 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) {
610 if (exec_sys_unregister(-1) < 0) {
611 dbg("exec_sys_unregister failed %d\n", errno);
614 dbg("exec_sys_unregister success\n");
618 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) {
619 dump_relocations(obj_main);
623 dbg("initializing key program variables");
624 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
625 set_program_var("environ", env);
627 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) {
628 extern void resident_start(void);
630 if (exec_sys_register(resident_start) < 0) {
631 dbg("exec_sys_register failed %d\n", errno);
634 dbg("exec_sys_register success\n");
638 /* Make a list of init functions to call. */
639 objlist_init(&initlist);
640 initlist_add_objects(obj_list, preload_tail, &initlist);
642 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
645 * Do NOT call the initlist here, give libc a chance to set up
646 * the initial TLS segment. crt1 will then call _rtld_call_init().
649 dbg("transferring control to program entry point = %p", obj_main->entry);
651 /* Return the exit procedure and the program entry point. */
652 *exit_proc = rtld_exit;
654 return (func_ptr_type) obj_main->entry;
658 * Call the initialization list for dynamically loaded libraries.
659 * (called from crt1.c).
662 _rtld_call_init(void)
664 RtldLockState lockstate;
666 wlock_acquire(rtld_bind_lock, &lockstate);
667 objlist_call_init(&initlist, &lockstate);
668 objlist_clear(&initlist);
669 lock_release(rtld_bind_lock, &lockstate);
673 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack)
677 const Obj_Entry *defobj;
680 RtldLockState lockstate;
683 rlock_acquire(rtld_bind_lock, &lockstate);
684 if (sigsetjmp(lockstate.env, 0) != 0)
685 lock_upgrade(rtld_bind_lock, &lockstate);
687 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
689 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
691 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
692 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL);
696 target = (Elf_Addr)(defobj->relocbase + def->st_value);
698 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
699 defobj->strtab + def->st_name, basename(obj->path),
700 (void *)target, basename(defobj->path));
703 * If we have a function call tracing hook, and the
704 * hook would like to keep tracing this one function,
705 * prevent the relocation so we will wind up here
706 * the next time again.
708 * We don't want to functrace calls from the functracer
709 * to avoid recursive loops.
711 if (rtld_functrace != NULL && obj != rtld_functrace_obj) {
712 if (rtld_functrace(obj->path,
714 defobj->strtab + def->st_name,
720 target = reloc_jmpslot(where, target, defobj, obj, rel);
721 lock_release(rtld_bind_lock, &lockstate);
726 * Error reporting function. Use it like printf. If formats the message
727 * into a buffer, and sets things up so that the next call to dlerror()
728 * will return the message.
731 _rtld_error(const char *fmt, ...)
733 static char buf[512];
737 vsnprintf(buf, sizeof buf, fmt, ap);
743 * Return a dynamically-allocated copy of the current error message, if any.
748 return error_message == NULL ? NULL : xstrdup(error_message);
752 * Restore the current error message from a copy which was previously saved
753 * by errmsg_save(). The copy is freed.
756 errmsg_restore(char *saved_msg)
758 if (saved_msg == NULL)
759 error_message = NULL;
761 _rtld_error("%s", saved_msg);
767 basename(const char *name)
769 const char *p = strrchr(name, '/');
770 return p != NULL ? p + 1 : name;
773 static struct utsname uts;
776 origin_subst_one(char **res, const char *real, const char *kw, const char *subst,
786 subst_len = kw_len = 0;
790 if (subst_len == 0) {
791 subst_len = strlen(subst);
795 *res = xmalloc(PATH_MAX);
798 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) {
799 _rtld_error("Substitution of %s in %s cannot be performed",
801 if (may_free != NULL)
806 memcpy(res1, p, p1 - p);
808 memcpy(res1, subst, subst_len);
813 if (may_free != NULL)
816 *res = xstrdup(real);
820 if (may_free != NULL)
822 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) {
832 origin_subst(const char *real, const char *origin_path)
834 char *res1, *res2, *res3, *res4;
836 if (uts.sysname[0] == '\0') {
837 if (uname(&uts) != 0) {
838 _rtld_error("utsname failed: %d", errno);
842 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) ||
843 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) ||
844 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) ||
845 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3))
853 const char *msg = dlerror();
861 * Process a shared object's DYNAMIC section, and save the important
862 * information in its Obj_Entry structure.
865 digest_dynamic(Obj_Entry *obj, int early)
868 Needed_Entry **needed_tail = &obj->needed;
869 const Elf_Dyn *dyn_rpath = NULL;
870 const Elf_Dyn *dyn_soname = NULL;
871 int plttype = DT_REL;
873 obj->bind_now = false;
874 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
875 switch (dynp->d_tag) {
878 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
882 obj->relsize = dynp->d_un.d_val;
886 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
890 obj->pltrel = (const Elf_Rel *)
891 (obj->relocbase + dynp->d_un.d_ptr);
895 obj->pltrelsize = dynp->d_un.d_val;
899 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
903 obj->relasize = dynp->d_un.d_val;
907 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
911 plttype = dynp->d_un.d_val;
912 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
916 obj->symtab = (const Elf_Sym *)
917 (obj->relocbase + dynp->d_un.d_ptr);
921 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
925 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
929 obj->strsize = dynp->d_un.d_val;
933 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
938 obj->verneednum = dynp->d_un.d_val;
942 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
947 obj->verdefnum = dynp->d_un.d_val;
951 obj->versyms = (const Elf_Versym *)(obj->relocbase +
957 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
958 (obj->relocbase + dynp->d_un.d_ptr);
959 obj->nbuckets = hashtab[0];
960 obj->nchains = hashtab[1];
961 obj->buckets = hashtab + 2;
962 obj->chains = obj->buckets + obj->nbuckets;
968 Needed_Entry *nep = NEW(Needed_Entry);
969 nep->name = dynp->d_un.d_val;
974 needed_tail = &nep->next;
979 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
987 obj->symbolic = true;
991 case DT_RUNPATH: /* XXX: process separately */
993 * We have to wait until later to process this, because we
994 * might not have gotten the address of the string table yet.
1004 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1008 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1012 /* XXX - not implemented yet */
1014 dbg("Filling in DT_DEBUG entry");
1015 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1019 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1020 obj->z_origin = true;
1021 if (dynp->d_un.d_val & DF_SYMBOLIC)
1022 obj->symbolic = true;
1023 if (dynp->d_un.d_val & DF_TEXTREL)
1024 obj->textrel = true;
1025 if (dynp->d_un.d_val & DF_BIND_NOW)
1026 obj->bind_now = true;
1027 if (dynp->d_un.d_val & DF_STATIC_TLS)
1032 if (dynp->d_un.d_val & DF_1_NOOPEN)
1033 obj->z_noopen = true;
1034 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1035 obj->z_origin = true;
1036 if (dynp->d_un.d_val & DF_1_GLOBAL)
1038 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1039 obj->bind_now = true;
1040 if (dynp->d_un.d_val & DF_1_NODELETE)
1041 obj->z_nodelete = true;
1046 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1053 obj->traced = false;
1055 if (plttype == DT_RELA) {
1056 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1058 obj->pltrelasize = obj->pltrelsize;
1059 obj->pltrelsize = 0;
1062 if (obj->z_origin && obj->origin_path == NULL) {
1063 obj->origin_path = xmalloc(PATH_MAX);
1064 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1068 if (dyn_rpath != NULL) {
1069 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1071 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1074 if (dyn_soname != NULL)
1075 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1079 * Process a shared object's program header. This is used only for the
1080 * main program, when the kernel has already loaded the main program
1081 * into memory before calling the dynamic linker. It creates and
1082 * returns an Obj_Entry structure.
1085 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1088 const Elf_Phdr *phlimit = phdr + phnum;
1093 for (ph = phdr; ph < phlimit; ph++) {
1094 if (ph->p_type != PT_PHDR)
1098 obj->phsize = ph->p_memsz;
1099 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1103 for (ph = phdr; ph < phlimit; ph++) {
1104 switch (ph->p_type) {
1107 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1111 if (nsegs == 0) { /* First load segment */
1112 obj->vaddrbase = trunc_page(ph->p_vaddr);
1113 obj->mapbase = obj->vaddrbase + obj->relocbase;
1114 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1116 } else { /* Last load segment */
1117 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1124 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1129 obj->tlssize = ph->p_memsz;
1130 obj->tlsalign = ph->p_align;
1131 obj->tlsinitsize = ph->p_filesz;
1132 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1137 _rtld_error("%s: too few PT_LOAD segments", path);
1146 dlcheck(void *handle)
1150 for (obj = obj_list; obj != NULL; obj = obj->next)
1151 if (obj == (Obj_Entry *) handle)
1154 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1155 _rtld_error("Invalid shared object handle %p", handle);
1162 * If the given object is already in the donelist, return true. Otherwise
1163 * add the object to the list and return false.
1166 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1170 for (i = 0; i < dlp->num_used; i++)
1171 if (dlp->objs[i] == obj)
1174 * Our donelist allocation should always be sufficient. But if
1175 * our threads locking isn't working properly, more shared objects
1176 * could have been loaded since we allocated the list. That should
1177 * never happen, but we'll handle it properly just in case it does.
1179 if (dlp->num_used < dlp->num_alloc)
1180 dlp->objs[dlp->num_used++] = obj;
1185 * Hash function for symbol table lookup. Don't even think about changing
1186 * this. It is specified by the System V ABI.
1189 elf_hash(const char *name)
1191 const unsigned char *p = (const unsigned char *) name;
1192 unsigned long h = 0;
1195 while (*p != '\0') {
1196 h = (h << 4) + *p++;
1197 if ((g = h & 0xf0000000) != 0)
1205 * Find the library with the given name, and return its full pathname.
1206 * The returned string is dynamically allocated. Generates an error
1207 * message and returns NULL if the library cannot be found.
1209 * If the second argument is non-NULL, then it refers to an already-
1210 * loaded shared object, whose library search path will be searched.
1212 * The search order is:
1214 * rpath in the referencing file
1219 find_library(const char *xname, const Obj_Entry *refobj)
1224 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1225 if (xname[0] != '/' && !trust) {
1226 _rtld_error("Absolute pathname required for shared object \"%s\"",
1230 if (refobj != NULL && refobj->z_origin)
1231 return origin_subst(xname, refobj->origin_path);
1233 return xstrdup(xname);
1236 if (libmap_disable || (refobj == NULL) ||
1237 (name = lm_find(refobj->path, xname)) == NULL)
1238 name = (char *)xname;
1240 dbg(" Searching for \"%s\"", name);
1242 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1244 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1245 (pathname = search_library_path(name, gethints())) != NULL ||
1246 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1249 if(refobj != NULL && refobj->path != NULL) {
1250 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1251 name, basename(refobj->path));
1253 _rtld_error("Shared object \"%s\" not found", name);
1259 * Given a symbol number in a referencing object, find the corresponding
1260 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1261 * no definition was found. Returns a pointer to the Obj_Entry of the
1262 * defining object via the reference parameter DEFOBJ_OUT.
1265 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1266 const Obj_Entry **defobj_out, int flags, SymCache *cache)
1270 const Obj_Entry *defobj;
1271 const Ver_Entry *ventry;
1276 * If we have already found this symbol, get the information from
1279 if (symnum >= refobj->nchains)
1280 return NULL; /* Bad object */
1281 if (cache != NULL && cache[symnum].sym != NULL) {
1282 *defobj_out = cache[symnum].obj;
1283 return cache[symnum].sym;
1286 ref = refobj->symtab + symnum;
1287 name = refobj->strtab + ref->st_name;
1291 * We don't have to do a full scale lookup if the symbol is local.
1292 * We know it will bind to the instance in this load module; to
1293 * which we already have a pointer (ie ref). By not doing a lookup,
1294 * we not only improve performance, but it also avoids unresolvable
1295 * symbols when local symbols are not in the hash table.
1297 * This might occur for TLS module relocations, which simply use
1300 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1301 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1302 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1305 ventry = fetch_ventry(refobj, symnum);
1306 hash = elf_hash(name);
1307 def = symlook_default(name, hash, refobj, &defobj, ventry, flags);
1314 * If we found no definition and the reference is weak, treat the
1315 * symbol as having the value zero.
1317 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1323 *defobj_out = defobj;
1324 /* Record the information in the cache to avoid subsequent lookups. */
1325 if (cache != NULL) {
1326 cache[symnum].sym = def;
1327 cache[symnum].obj = defobj;
1330 if (refobj != &obj_rtld)
1331 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1337 * Return the search path from the ldconfig hints file, reading it if
1338 * necessary. Returns NULL if there are problems with the hints file,
1339 * or if the search path there is empty.
1346 if (hints == NULL) {
1348 struct elfhints_hdr hdr;
1351 /* Keep from trying again in case the hints file is bad. */
1354 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1356 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1357 hdr.magic != ELFHINTS_MAGIC ||
1362 p = xmalloc(hdr.dirlistlen + 1);
1363 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1364 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1372 return hints[0] != '\0' ? hints : NULL;
1376 init_dag(Obj_Entry *root)
1380 if (root->dag_inited)
1382 donelist_init(&donelist);
1383 init_dag1(root, root, &donelist);
1387 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp)
1389 const Needed_Entry *needed;
1391 if (donelist_check(dlp, obj))
1394 objlist_push_tail(&obj->dldags, root);
1395 objlist_push_tail(&root->dagmembers, obj);
1396 for (needed = obj->needed; needed != NULL; needed = needed->next)
1397 if (needed->obj != NULL)
1398 init_dag1(root, needed->obj, dlp);
1399 root->dag_inited = true;
1403 * Initialize the dynamic linker. The argument is the address at which
1404 * the dynamic linker has been mapped into memory. The primary task of
1405 * this function is to relocate the dynamic linker.
1408 init_rtld(caddr_t mapbase)
1410 Obj_Entry objtmp; /* Temporary rtld object */
1413 * Conjure up an Obj_Entry structure for the dynamic linker.
1415 * The "path" member can't be initialized yet because string constants
1416 * cannot yet be accessed. Below we will set it correctly.
1418 memset(&objtmp, 0, sizeof(objtmp));
1421 objtmp.mapbase = mapbase;
1423 objtmp.relocbase = mapbase;
1425 if (RTLD_IS_DYNAMIC()) {
1426 objtmp.dynamic = rtld_dynamic(&objtmp);
1427 digest_dynamic(&objtmp, 1);
1428 assert(objtmp.needed == NULL);
1429 assert(!objtmp.textrel);
1432 * Temporarily put the dynamic linker entry into the object list, so
1433 * that symbols can be found.
1436 relocate_objects(&objtmp, true, &objtmp);
1439 /* Initialize the object list. */
1440 obj_tail = &obj_list;
1442 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1443 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1445 /* Replace the path with a dynamically allocated copy. */
1446 obj_rtld.path = xstrdup(PATH_RTLD);
1448 r_debug.r_brk = r_debug_state;
1449 r_debug.r_state = RT_CONSISTENT;
1453 * Add the init functions from a needed object list (and its recursive
1454 * needed objects) to "list". This is not used directly; it is a helper
1455 * function for initlist_add_objects(). The write lock must be held
1456 * when this function is called.
1459 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1461 /* Recursively process the successor needed objects. */
1462 if (needed->next != NULL)
1463 initlist_add_neededs(needed->next, list);
1465 /* Process the current needed object. */
1466 if (needed->obj != NULL)
1467 initlist_add_objects(needed->obj, &needed->obj->next, list);
1471 * Scan all of the DAGs rooted in the range of objects from "obj" to
1472 * "tail" and add their init functions to "list". This recurses over
1473 * the DAGs and ensure the proper init ordering such that each object's
1474 * needed libraries are initialized before the object itself. At the
1475 * same time, this function adds the objects to the global finalization
1476 * list "list_fini" in the opposite order. The write lock must be
1477 * held when this function is called.
1480 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1482 if (obj->init_scanned || obj->init_done)
1484 obj->init_scanned = true;
1486 /* Recursively process the successor objects. */
1487 if (&obj->next != tail)
1488 initlist_add_objects(obj->next, tail, list);
1490 /* Recursively process the needed objects. */
1491 if (obj->needed != NULL)
1492 initlist_add_neededs(obj->needed, list);
1494 /* Add the object to the init list. */
1495 if (obj->init != (Elf_Addr)NULL)
1496 objlist_push_tail(list, obj);
1498 /* Add the object to the global fini list in the reverse order. */
1499 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) {
1500 objlist_push_head(&list_fini, obj);
1501 obj->on_fini_list = true;
1506 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1510 is_exported(const Elf_Sym *def)
1513 const func_ptr_type *p;
1515 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value);
1516 for (p = exports; *p != NULL; p++)
1517 if (FPTR_TARGET(*p) == value)
1523 * Given a shared object, traverse its list of needed objects, and load
1524 * each of them. Returns 0 on success. Generates an error message and
1525 * returns -1 on failure.
1528 load_needed_objects(Obj_Entry *first, int flags)
1530 Obj_Entry *obj, *obj1;
1532 for (obj = first; obj != NULL; obj = obj->next) {
1533 Needed_Entry *needed;
1535 for (needed = obj->needed; needed != NULL; needed = needed->next) {
1536 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj,
1537 flags & ~RTLD_LO_NOLOAD);
1538 if (obj1 == NULL && !ld_tracing)
1540 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
1541 dbg("obj %s nodelete", obj1->path);
1544 obj1->ref_nodel = true;
1551 #define RTLD_FUNCTRACE "_rtld_functrace"
1554 load_preload_objects(void)
1556 char *p = ld_preload;
1557 static const char delim[] = " \t:;";
1562 p += strspn(p, delim);
1563 while (*p != '\0') {
1564 size_t len = strcspn(p, delim);
1571 obj = load_object(p, NULL, 0);
1573 return -1; /* XXX - cleanup */
1576 p += strspn(p, delim);
1578 /* Check for the magic tracing function */
1579 sym = symlook_obj(RTLD_FUNCTRACE, elf_hash(RTLD_FUNCTRACE), obj, NULL, 1);
1581 rtld_functrace = (void *)(obj->relocbase + sym->st_value);
1582 rtld_functrace_obj = obj;
1585 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
1590 * Load a shared object into memory, if it is not already loaded.
1592 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1596 load_object(const char *name, const Obj_Entry *refobj, int flags)
1603 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1604 if (object_match_name(obj, name))
1607 path = find_library(name, refobj);
1612 * If we didn't find a match by pathname, open the file and check
1613 * again by device and inode. This avoids false mismatches caused
1614 * by multiple links or ".." in pathnames.
1616 * To avoid a race, we open the file and use fstat() rather than
1619 if ((fd = open(path, O_RDONLY)) == -1) {
1620 _rtld_error("Cannot open \"%s\"", path);
1624 if (fstat(fd, &sb) == -1) {
1625 _rtld_error("Cannot fstat \"%s\"", path);
1630 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1631 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
1634 object_add_name(obj, name);
1639 if (flags & RTLD_LO_NOLOAD) {
1645 /* First use of this object, so we must map it in */
1646 obj = do_load_object(fd, name, path, &sb, flags);
1655 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
1662 * but first, make sure that environment variables haven't been
1663 * used to circumvent the noexec flag on a filesystem.
1665 if (dangerous_ld_env) {
1666 if (fstatfs(fd, &fs) != 0) {
1667 _rtld_error("Cannot fstatfs \"%s\"", path);
1670 if (fs.f_flags & MNT_NOEXEC) {
1671 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
1675 dbg("loading \"%s\"", path);
1676 obj = map_object(fd, path, sbp);
1680 object_add_name(obj, name);
1682 digest_dynamic(obj, 0);
1683 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
1685 dbg("refusing to load non-loadable \"%s\"", obj->path);
1686 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
1687 munmap(obj->mapbase, obj->mapsize);
1693 obj_tail = &obj->next;
1696 linkmap_add(obj); /* for GDB & dlinfo() */
1698 dbg(" %p .. %p: %s", obj->mapbase,
1699 obj->mapbase + obj->mapsize - 1, obj->path);
1701 dbg(" WARNING: %s has impure text", obj->path);
1702 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
1709 obj_from_addr(const void *addr)
1713 for (obj = obj_list; obj != NULL; obj = obj->next) {
1714 if (addr < (void *) obj->mapbase)
1716 if (addr < (void *) (obj->mapbase + obj->mapsize))
1723 * Call the finalization functions for each of the objects in "list"
1724 * belonging to the DAG of "root" and referenced once. If NULL "root"
1725 * is specified, every finalization function will be called regardless
1726 * of the reference count and the list elements won't be freed. All of
1727 * the objects are expected to have non-NULL fini functions.
1730 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
1735 assert(root == NULL || root->refcount == 1);
1738 * Preserve the current error message since a fini function might
1739 * call into the dynamic linker and overwrite it.
1741 saved_msg = errmsg_save();
1743 STAILQ_FOREACH(elm, list, link) {
1744 if (root != NULL && (elm->obj->refcount != 1 ||
1745 objlist_find(&root->dagmembers, elm->obj) == NULL))
1747 dbg("calling fini function for %s at %p", elm->obj->path,
1748 (void *)elm->obj->fini);
1749 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0,
1751 /* Remove object from fini list to prevent recursive invocation. */
1752 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1754 * XXX: If a dlopen() call references an object while the
1755 * fini function is in progress, we might end up trying to
1756 * unload the referenced object in dlclose() or the object
1757 * won't be unloaded although its fini function has been
1760 lock_release(rtld_bind_lock, lockstate);
1761 call_initfini_pointer(elm->obj, elm->obj->fini);
1762 wlock_acquire(rtld_bind_lock, lockstate);
1763 /* No need to free anything if process is going down. */
1767 * We must restart the list traversal after every fini call
1768 * because a dlclose() call from the fini function or from
1769 * another thread might have modified the reference counts.
1773 } while (elm != NULL);
1774 errmsg_restore(saved_msg);
1778 * Call the initialization functions for each of the objects in
1779 * "list". All of the objects are expected to have non-NULL init
1783 objlist_call_init(Objlist *list, RtldLockState *lockstate)
1790 * Clean init_scanned flag so that objects can be rechecked and
1791 * possibly initialized earlier if any of vectors called below
1792 * cause the change by using dlopen.
1794 for (obj = obj_list; obj != NULL; obj = obj->next)
1795 obj->init_scanned = false;
1798 * Preserve the current error message since an init function might
1799 * call into the dynamic linker and overwrite it.
1801 saved_msg = errmsg_save();
1802 STAILQ_FOREACH(elm, list, link) {
1803 if (elm->obj->init_done) /* Initialized early. */
1805 dbg("calling init function for %s at %p", elm->obj->path,
1806 (void *)elm->obj->init);
1807 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0,
1810 * Race: other thread might try to use this object before current
1811 * one completes the initilization. Not much can be done here
1812 * without better locking.
1814 elm->obj->init_done = true;
1815 lock_release(rtld_bind_lock, lockstate);
1816 call_initfini_pointer(elm->obj, elm->obj->init);
1817 wlock_acquire(rtld_bind_lock, lockstate);
1819 errmsg_restore(saved_msg);
1823 objlist_clear(Objlist *list)
1827 while (!STAILQ_EMPTY(list)) {
1828 elm = STAILQ_FIRST(list);
1829 STAILQ_REMOVE_HEAD(list, link);
1834 static Objlist_Entry *
1835 objlist_find(Objlist *list, const Obj_Entry *obj)
1839 STAILQ_FOREACH(elm, list, link)
1840 if (elm->obj == obj)
1846 objlist_init(Objlist *list)
1852 objlist_push_head(Objlist *list, Obj_Entry *obj)
1856 elm = NEW(Objlist_Entry);
1858 STAILQ_INSERT_HEAD(list, elm, link);
1862 objlist_push_tail(Objlist *list, Obj_Entry *obj)
1866 elm = NEW(Objlist_Entry);
1868 STAILQ_INSERT_TAIL(list, elm, link);
1872 objlist_remove(Objlist *list, Obj_Entry *obj)
1876 if ((elm = objlist_find(list, obj)) != NULL) {
1877 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1883 * Relocate newly-loaded shared objects. The argument is a pointer to
1884 * the Obj_Entry for the first such object. All objects from the first
1885 * to the end of the list of objects are relocated. Returns 0 on success,
1889 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj)
1893 for (obj = first; obj != NULL; obj = obj->next) {
1895 dbg("relocating \"%s\"", obj->path);
1896 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
1897 obj->symtab == NULL || obj->strtab == NULL) {
1898 _rtld_error("%s: Shared object has no run-time symbol table",
1904 /* There are relocations to the write-protected text segment. */
1905 if (mprotect(obj->mapbase, obj->textsize,
1906 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
1907 _rtld_error("%s: Cannot write-enable text segment: %s",
1908 obj->path, strerror(errno));
1913 /* Process the non-PLT relocations. */
1914 if (reloc_non_plt(obj, rtldobj))
1918 * Reprotect the text segment. Make sure it is included in the
1919 * core dump since we modified it. This unfortunately causes the
1920 * entire text segment to core-out but we don't have much of a
1921 * choice. We could try to only reenable core dumps on pages
1922 * in which relocations occured but that is likely most of the text
1923 * pages anyway, and even that would not work because the rest of
1924 * the text pages would wind up as a read-only OBJT_DEFAULT object
1925 * (created due to our modifications) backed by the original OBJT_VNODE
1926 * object, and the ELF coredump code is currently only able to dump
1927 * vnode records for pure vnode-backed mappings, not vnode backings
1928 * to memory objects.
1931 madvise(obj->mapbase, obj->textsize, MADV_CORE);
1932 if (mprotect(obj->mapbase, obj->textsize,
1933 PROT_READ|PROT_EXEC) == -1) {
1934 _rtld_error("%s: Cannot write-protect text segment: %s",
1935 obj->path, strerror(errno));
1940 /* Process the PLT relocations. */
1941 if (reloc_plt(obj) == -1)
1943 /* Relocate the jump slots if we are doing immediate binding. */
1944 if (obj->bind_now || bind_now)
1945 if (reloc_jmpslots(obj) == -1)
1950 * Set up the magic number and version in the Obj_Entry. These
1951 * were checked in the crt1.o from the original ElfKit, so we
1952 * set them for backward compatibility.
1954 obj->magic = RTLD_MAGIC;
1955 obj->version = RTLD_VERSION;
1957 /* Set the special PLT or GOT entries. */
1965 * Cleanup procedure. It will be called (by the atexit mechanism) just
1966 * before the process exits.
1971 RtldLockState lockstate;
1973 wlock_acquire(rtld_bind_lock, &lockstate);
1975 objlist_call_fini(&list_fini, NULL, &lockstate);
1976 /* No need to remove the items from the list, since we are exiting. */
1977 if (!libmap_disable)
1979 lock_release(rtld_bind_lock, &lockstate);
1983 path_enumerate(const char *path, path_enum_proc callback, void *arg)
1988 path += strspn(path, ":;");
1989 while (*path != '\0') {
1993 len = strcspn(path, ":;");
1994 res = callback(path, len, arg);
2000 path += strspn(path, ":;");
2006 struct try_library_args {
2014 try_library_path(const char *dir, size_t dirlen, void *param)
2016 struct try_library_args *arg;
2019 if (*dir == '/' || trust) {
2022 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2025 pathname = arg->buffer;
2026 strncpy(pathname, dir, dirlen);
2027 pathname[dirlen] = '/';
2028 strcpy(pathname + dirlen + 1, arg->name);
2030 dbg(" Trying \"%s\"", pathname);
2031 if (access(pathname, F_OK) == 0) { /* We found it */
2032 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2033 strcpy(pathname, arg->buffer);
2041 search_library_path(const char *name, const char *path)
2044 struct try_library_args arg;
2050 arg.namelen = strlen(name);
2051 arg.buffer = xmalloc(PATH_MAX);
2052 arg.buflen = PATH_MAX;
2054 p = path_enumerate(path, try_library_path, &arg);
2062 dlclose(void *handle)
2065 RtldLockState lockstate;
2067 wlock_acquire(rtld_bind_lock, &lockstate);
2068 root = dlcheck(handle);
2070 lock_release(rtld_bind_lock, &lockstate);
2073 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2076 /* Unreference the object and its dependencies. */
2077 root->dl_refcount--;
2079 if (root->refcount == 1) {
2081 * The object will be no longer referenced, so we must unload it.
2082 * First, call the fini functions.
2084 objlist_call_fini(&list_fini, root, &lockstate);
2088 /* Finish cleaning up the newly-unreferenced objects. */
2089 GDB_STATE(RT_DELETE,&root->linkmap);
2090 unload_object(root);
2091 GDB_STATE(RT_CONSISTENT,NULL);
2095 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2096 lock_release(rtld_bind_lock, &lockstate);
2103 char *msg = error_message;
2104 error_message = NULL;
2109 dlopen(const char *name, int mode)
2111 Obj_Entry **old_obj_tail;
2114 RtldLockState lockstate;
2115 int result, lo_flags;
2117 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2118 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2119 if (ld_tracing != NULL)
2120 environ = (char **)*get_program_var_addr("environ");
2121 lo_flags = RTLD_LO_DLOPEN;
2122 if (mode & RTLD_NODELETE)
2123 lo_flags |= RTLD_LO_NODELETE;
2124 if (mode & RTLD_NOLOAD)
2125 lo_flags |= RTLD_LO_NOLOAD;
2126 if (ld_tracing != NULL)
2127 lo_flags |= RTLD_LO_TRACE;
2129 objlist_init(&initlist);
2131 wlock_acquire(rtld_bind_lock, &lockstate);
2132 GDB_STATE(RT_ADD,NULL);
2134 old_obj_tail = obj_tail;
2140 obj = load_object(name, obj_main, lo_flags);
2145 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2146 objlist_push_tail(&list_global, obj);
2147 mode &= RTLD_MODEMASK;
2148 if (*old_obj_tail != NULL) { /* We loaded something new. */
2149 assert(*old_obj_tail == obj);
2150 result = load_needed_objects(obj, RTLD_LO_DLOPEN);
2154 result = rtld_verify_versions(&obj->dagmembers);
2155 if (result != -1 && ld_tracing)
2158 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) {
2161 if (obj->refcount == 0)
2165 /* Make list of init functions to call. */
2166 initlist_add_objects(obj, &obj->next, &initlist);
2171 * Bump the reference counts for objects on this DAG. If
2172 * this is the first dlopen() call for the object that was
2173 * already loaded as a dependency, initialize the dag
2179 if ((lo_flags & RTLD_LO_TRACE) != 0)
2182 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2183 obj->z_nodelete) && !obj->ref_nodel) {
2184 dbg("obj %s nodelete", obj->path);
2186 obj->z_nodelete = obj->ref_nodel = true;
2190 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2192 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2194 /* Call the init functions. */
2195 objlist_call_init(&initlist, &lockstate);
2196 objlist_clear(&initlist);
2197 lock_release(rtld_bind_lock, &lockstate);
2200 trace_loaded_objects(obj);
2201 lock_release(rtld_bind_lock, &lockstate);
2206 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2210 const Obj_Entry *obj, *defobj;
2211 const Elf_Sym *def, *symp;
2213 RtldLockState lockstate;
2215 hash = elf_hash(name);
2218 flags |= SYMLOOK_IN_PLT;
2220 rlock_acquire(rtld_bind_lock, &lockstate);
2221 if (sigsetjmp(lockstate.env, 0) != 0)
2222 lock_upgrade(rtld_bind_lock, &lockstate);
2223 if (handle == NULL || handle == RTLD_NEXT ||
2224 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2226 if ((obj = obj_from_addr(retaddr)) == NULL) {
2227 _rtld_error("Cannot determine caller's shared object");
2228 lock_release(rtld_bind_lock, &lockstate);
2231 if (handle == NULL) { /* Just the caller's shared object. */
2232 def = symlook_obj(name, hash, obj, ve, flags);
2234 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2235 handle == RTLD_SELF) { /* ... caller included */
2236 if (handle == RTLD_NEXT)
2238 for (; obj != NULL; obj = obj->next) {
2239 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) {
2240 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) {
2243 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2249 * Search the dynamic linker itself, and possibly resolve the
2250 * symbol from there. This is how the application links to
2251 * dynamic linker services such as dlopen.
2253 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2254 symp = symlook_obj(name, hash, &obj_rtld, ve, flags);
2261 assert(handle == RTLD_DEFAULT);
2262 def = symlook_default(name, hash, obj, &defobj, ve, flags);
2265 if ((obj = dlcheck(handle)) == NULL) {
2266 lock_release(rtld_bind_lock, &lockstate);
2270 donelist_init(&donelist);
2271 if (obj->mainprog) {
2272 /* Search main program and all libraries loaded by it. */
2273 def = symlook_list(name, hash, &list_main, &defobj, ve, flags,
2277 * We do not distinguish between 'main' object and global scope.
2278 * If symbol is not defined by objects loaded at startup, continue
2279 * search among dynamically loaded objects with RTLD_GLOBAL
2283 def = symlook_list(name, hash, &list_global, &defobj, ve,
2288 /* Search the whole DAG rooted at the given object. */
2290 fake.obj = (Obj_Entry *)obj;
2292 def = symlook_needed(name, hash, &fake, &defobj, ve, flags,
2298 lock_release(rtld_bind_lock, &lockstate);
2301 * The value required by the caller is derived from the value
2302 * of the symbol. For the ia64 architecture, we need to
2303 * construct a function descriptor which the caller can use to
2304 * call the function with the right 'gp' value. For other
2305 * architectures and for non-functions, the value is simply
2306 * the relocated value of the symbol.
2308 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
2309 return make_function_pointer(def, defobj);
2311 return defobj->relocbase + def->st_value;
2314 _rtld_error("Undefined symbol \"%s\"", name);
2315 lock_release(rtld_bind_lock, &lockstate);
2320 dlsym(void *handle, const char *name)
2322 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2327 dlfunc(void *handle, const char *name)
2334 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
2340 dlvsym(void *handle, const char *name, const char *version)
2344 ventry.name = version;
2346 ventry.hash = elf_hash(version);
2348 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2353 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
2355 const Obj_Entry *obj;
2356 RtldLockState lockstate;
2358 rlock_acquire(rtld_bind_lock, &lockstate);
2359 obj = obj_from_addr(addr);
2361 _rtld_error("No shared object contains address");
2362 lock_release(rtld_bind_lock, &lockstate);
2365 rtld_fill_dl_phdr_info(obj, phdr_info);
2366 lock_release(rtld_bind_lock, &lockstate);
2371 dladdr(const void *addr, Dl_info *info)
2373 const Obj_Entry *obj;
2376 unsigned long symoffset;
2377 RtldLockState lockstate;
2379 rlock_acquire(rtld_bind_lock, &lockstate);
2380 obj = obj_from_addr(addr);
2382 _rtld_error("No shared object contains address");
2383 lock_release(rtld_bind_lock, &lockstate);
2386 info->dli_fname = obj->path;
2387 info->dli_fbase = obj->mapbase;
2388 info->dli_saddr = NULL;
2389 info->dli_sname = NULL;
2392 * Walk the symbol list looking for the symbol whose address is
2393 * closest to the address sent in.
2395 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
2396 def = obj->symtab + symoffset;
2399 * For skip the symbol if st_shndx is either SHN_UNDEF or
2402 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2406 * If the symbol is greater than the specified address, or if it
2407 * is further away from addr than the current nearest symbol,
2410 symbol_addr = obj->relocbase + def->st_value;
2411 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2414 /* Update our idea of the nearest symbol. */
2415 info->dli_sname = obj->strtab + def->st_name;
2416 info->dli_saddr = symbol_addr;
2419 if (info->dli_saddr == addr)
2422 lock_release(rtld_bind_lock, &lockstate);
2427 dlinfo(void *handle, int request, void *p)
2429 const Obj_Entry *obj;
2430 RtldLockState lockstate;
2433 rlock_acquire(rtld_bind_lock, &lockstate);
2435 if (handle == NULL || handle == RTLD_SELF) {
2438 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2439 if ((obj = obj_from_addr(retaddr)) == NULL)
2440 _rtld_error("Cannot determine caller's shared object");
2442 obj = dlcheck(handle);
2445 lock_release(rtld_bind_lock, &lockstate);
2451 case RTLD_DI_LINKMAP:
2452 *((struct link_map const **)p) = &obj->linkmap;
2454 case RTLD_DI_ORIGIN:
2455 error = rtld_dirname(obj->path, p);
2458 case RTLD_DI_SERINFOSIZE:
2459 case RTLD_DI_SERINFO:
2460 error = do_search_info(obj, request, (struct dl_serinfo *)p);
2464 _rtld_error("Invalid request %d passed to dlinfo()", request);
2468 lock_release(rtld_bind_lock, &lockstate);
2474 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
2477 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
2478 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
2479 STAILQ_FIRST(&obj->names)->name : obj->path;
2480 phdr_info->dlpi_phdr = obj->phdr;
2481 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
2482 phdr_info->dlpi_tls_modid = obj->tlsindex;
2483 phdr_info->dlpi_tls_data = obj->tlsinit;
2484 phdr_info->dlpi_adds = obj_loads;
2485 phdr_info->dlpi_subs = obj_loads - obj_count;
2489 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
2491 struct dl_phdr_info phdr_info;
2492 const Obj_Entry *obj;
2493 RtldLockState bind_lockstate, phdr_lockstate;
2496 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
2497 rlock_acquire(rtld_bind_lock, &bind_lockstate);
2501 for (obj = obj_list; obj != NULL; obj = obj->next) {
2502 rtld_fill_dl_phdr_info(obj, &phdr_info);
2503 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
2507 lock_release(rtld_bind_lock, &bind_lockstate);
2508 lock_release(rtld_phdr_lock, &phdr_lockstate);
2513 struct fill_search_info_args {
2516 Dl_serinfo *serinfo;
2517 Dl_serpath *serpath;
2522 fill_search_info(const char *dir, size_t dirlen, void *param)
2524 struct fill_search_info_args *arg;
2528 if (arg->request == RTLD_DI_SERINFOSIZE) {
2529 arg->serinfo->dls_cnt ++;
2530 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
2532 struct dl_serpath *s_entry;
2534 s_entry = arg->serpath;
2535 s_entry->dls_name = arg->strspace;
2536 s_entry->dls_flags = arg->flags;
2538 strncpy(arg->strspace, dir, dirlen);
2539 arg->strspace[dirlen] = '\0';
2541 arg->strspace += dirlen + 1;
2549 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2551 struct dl_serinfo _info;
2552 struct fill_search_info_args args;
2554 args.request = RTLD_DI_SERINFOSIZE;
2555 args.serinfo = &_info;
2557 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2560 path_enumerate(ld_library_path, fill_search_info, &args);
2561 path_enumerate(obj->rpath, fill_search_info, &args);
2562 path_enumerate(gethints(), fill_search_info, &args);
2563 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
2566 if (request == RTLD_DI_SERINFOSIZE) {
2567 info->dls_size = _info.dls_size;
2568 info->dls_cnt = _info.dls_cnt;
2572 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
2573 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
2577 args.request = RTLD_DI_SERINFO;
2578 args.serinfo = info;
2579 args.serpath = &info->dls_serpath[0];
2580 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
2582 args.flags = LA_SER_LIBPATH;
2583 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
2586 args.flags = LA_SER_RUNPATH;
2587 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
2590 args.flags = LA_SER_CONFIG;
2591 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
2594 args.flags = LA_SER_DEFAULT;
2595 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
2601 rtld_dirname(const char *path, char *bname)
2605 /* Empty or NULL string gets treated as "." */
2606 if (path == NULL || *path == '\0') {
2612 /* Strip trailing slashes */
2613 endp = path + strlen(path) - 1;
2614 while (endp > path && *endp == '/')
2617 /* Find the start of the dir */
2618 while (endp > path && *endp != '/')
2621 /* Either the dir is "/" or there are no slashes */
2623 bname[0] = *endp == '/' ? '/' : '.';
2629 } while (endp > path && *endp == '/');
2632 if (endp - path + 2 > PATH_MAX)
2634 _rtld_error("Filename is too long: %s", path);
2638 strncpy(bname, path, endp - path + 1);
2639 bname[endp - path + 1] = '\0';
2644 rtld_dirname_abs(const char *path, char *base)
2646 char base_rel[PATH_MAX];
2648 if (rtld_dirname(path, base) == -1)
2652 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
2653 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
2654 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
2656 strcpy(base, base_rel);
2661 linkmap_add(Obj_Entry *obj)
2663 struct link_map *l = &obj->linkmap;
2664 struct link_map *prev;
2666 obj->linkmap.l_name = obj->path;
2667 obj->linkmap.l_addr = obj->mapbase;
2668 obj->linkmap.l_ld = obj->dynamic;
2670 /* GDB needs load offset on MIPS to use the symbols */
2671 obj->linkmap.l_offs = obj->relocbase;
2674 if (r_debug.r_map == NULL) {
2680 * Scan to the end of the list, but not past the entry for the
2681 * dynamic linker, which we want to keep at the very end.
2683 for (prev = r_debug.r_map;
2684 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
2685 prev = prev->l_next)
2688 /* Link in the new entry. */
2690 l->l_next = prev->l_next;
2691 if (l->l_next != NULL)
2692 l->l_next->l_prev = l;
2697 linkmap_delete(Obj_Entry *obj)
2699 struct link_map *l = &obj->linkmap;
2701 if (l->l_prev == NULL) {
2702 if ((r_debug.r_map = l->l_next) != NULL)
2703 l->l_next->l_prev = NULL;
2707 if ((l->l_prev->l_next = l->l_next) != NULL)
2708 l->l_next->l_prev = l->l_prev;
2712 * Function for the debugger to set a breakpoint on to gain control.
2714 * The two parameters allow the debugger to easily find and determine
2715 * what the runtime loader is doing and to whom it is doing it.
2717 * When the loadhook trap is hit (r_debug_state, set at program
2718 * initialization), the arguments can be found on the stack:
2720 * +8 struct link_map *m
2721 * +4 struct r_debug *rd
2725 r_debug_state(struct r_debug* rd, struct link_map *m)
2730 * Get address of the pointer variable in the main program.
2732 static const void **
2733 get_program_var_addr(const char *name)
2735 const Obj_Entry *obj;
2738 hash = elf_hash(name);
2739 for (obj = obj_main; obj != NULL; obj = obj->next) {
2742 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) {
2745 addr = (const void **)(obj->relocbase + def->st_value);
2753 * Set a pointer variable in the main program to the given value. This
2754 * is used to set key variables such as "environ" before any of the
2755 * init functions are called.
2758 set_program_var(const char *name, const void *value)
2762 if ((addr = get_program_var_addr(name)) != NULL) {
2763 dbg("\"%s\": *%p <-- %p", name, addr, value);
2769 * This is a special version of getenv which is far more efficient
2770 * at finding LD_ environment vars.
2774 _getenv_ld(const char *id)
2778 int idlen = strlen(id);
2780 if (ld_index == LD_ARY_CACHE)
2782 if (ld_index == 0) {
2783 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) {
2784 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_')
2791 for (i = ld_index - 1; i >= 0; --i) {
2792 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=')
2793 return(ld_ary[i] + idlen + 1);
2799 * Given a symbol name in a referencing object, find the corresponding
2800 * definition of the symbol. Returns a pointer to the symbol, or NULL if
2801 * no definition was found. Returns a pointer to the Obj_Entry of the
2802 * defining object via the reference parameter DEFOBJ_OUT.
2804 static const Elf_Sym *
2805 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj,
2806 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags)
2810 const Elf_Sym *symp;
2811 const Obj_Entry *obj;
2812 const Obj_Entry *defobj;
2813 const Objlist_Entry *elm;
2816 donelist_init(&donelist);
2818 /* Look first in the referencing object if linked symbolically. */
2819 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
2820 symp = symlook_obj(name, hash, refobj, ventry, flags);
2827 /* Search all objects loaded at program start up. */
2828 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2829 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags,
2832 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2838 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
2839 STAILQ_FOREACH(elm, &list_global, link) {
2840 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
2842 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry,
2845 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2851 /* Search all dlopened DAGs containing the referencing object. */
2852 STAILQ_FOREACH(elm, &refobj->dldags, link) {
2853 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
2855 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry,
2858 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2865 * Search the dynamic linker itself, and possibly resolve the
2866 * symbol from there. This is how the application links to
2867 * dynamic linker services such as dlopen. Only the values listed
2868 * in the "exports" array can be resolved from the dynamic linker.
2870 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2871 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags);
2872 if (symp != NULL && is_exported(symp)) {
2879 *defobj_out = defobj;
2883 static const Elf_Sym *
2884 symlook_list(const char *name, unsigned long hash, const Objlist *objlist,
2885 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags,
2888 const Elf_Sym *symp;
2890 const Obj_Entry *defobj;
2891 const Objlist_Entry *elm;
2895 STAILQ_FOREACH(elm, objlist, link) {
2896 if (donelist_check(dlp, elm->obj))
2898 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) {
2899 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) {
2902 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2908 *defobj_out = defobj;
2913 * Search the symbol table of a shared object and all objects needed
2914 * by it for a symbol of the given name. Search order is
2915 * breadth-first. Returns a pointer to the symbol, or NULL if no
2916 * definition was found.
2918 static const Elf_Sym *
2919 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed,
2920 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags,
2923 const Elf_Sym *def, *def_w;
2924 const Needed_Entry *n;
2925 const Obj_Entry *obj, *defobj, *defobj1;
2929 for (n = needed; n != NULL; n = n->next) {
2930 if ((obj = n->obj) == NULL ||
2931 donelist_check(dlp, obj) ||
2932 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL)
2935 if (ELF_ST_BIND(def->st_info) != STB_WEAK) {
2936 *defobj_out = defobj;
2941 * There we come when either symbol definition is not found in
2942 * directly needed objects, or found symbol is weak.
2944 for (n = needed; n != NULL; n = n->next) {
2945 if ((obj = n->obj) == NULL)
2947 def_w = symlook_needed(name, hash, obj->needed, &defobj1,
2948 ventry, flags, dlp);
2951 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) {
2955 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK)
2959 *defobj_out = defobj;
2964 * Search the symbol table of a single shared object for a symbol of
2965 * the given name and version, if requested. Returns a pointer to the
2966 * symbol, or NULL if no definition was found.
2968 * The symbol's hash value is passed in for efficiency reasons; that
2969 * eliminates many recomputations of the hash value.
2972 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj,
2973 const Ver_Entry *ventry, int flags)
2975 unsigned long symnum;
2976 const Elf_Sym *vsymp;
2980 if (obj->buckets == NULL)
2985 symnum = obj->buckets[hash % obj->nbuckets];
2987 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
2988 const Elf_Sym *symp;
2991 if (symnum >= obj->nchains)
2992 return NULL; /* Bad object */
2994 symp = obj->symtab + symnum;
2995 strp = obj->strtab + symp->st_name;
2997 switch (ELF_ST_TYPE(symp->st_info)) {
3001 if (symp->st_value == 0)
3005 if (symp->st_shndx != SHN_UNDEF)
3007 else if (((flags & SYMLOOK_IN_PLT) == 0) &&
3008 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3014 if (name[0] != strp[0] || strcmp(name, strp) != 0)
3017 if (ventry == NULL) {
3018 if (obj->versyms != NULL) {
3019 verndx = VER_NDX(obj->versyms[symnum]);
3020 if (verndx > obj->vernum) {
3021 _rtld_error("%s: symbol %s references wrong version %d",
3022 obj->path, obj->strtab + symnum, verndx);
3026 * If we are not called from dlsym (i.e. this is a normal
3027 * relocation from unversioned binary), accept the symbol
3028 * immediately if it happens to have first version after
3029 * this shared object became versioned. Otherwise, if
3030 * symbol is versioned and not hidden, remember it. If it
3031 * is the only symbol with this name exported by the
3032 * shared object, it will be returned as a match at the
3033 * end of the function. If symbol is global (verndx < 2)
3034 * accept it unconditionally.
3036 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN)
3038 else if (verndx >= VER_NDX_GIVEN) {
3039 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
3049 if (obj->versyms == NULL) {
3050 if (object_match_name(obj, ventry->name)) {
3051 _rtld_error("%s: object %s should provide version %s for "
3052 "symbol %s", obj_rtld.path, obj->path, ventry->name,
3053 obj->strtab + symnum);
3057 verndx = VER_NDX(obj->versyms[symnum]);
3058 if (verndx > obj->vernum) {
3059 _rtld_error("%s: symbol %s references wrong version %d",
3060 obj->path, obj->strtab + symnum, verndx);
3063 if (obj->vertab[verndx].hash != ventry->hash ||
3064 strcmp(obj->vertab[verndx].name, ventry->name)) {
3066 * Version does not match. Look if this is a global symbol
3067 * and if it is not hidden. If global symbol (verndx < 2)
3068 * is available, use it. Do not return symbol if we are
3069 * called by dlvsym, because dlvsym looks for a specific
3070 * version and default one is not what dlvsym wants.
3072 if ((flags & SYMLOOK_DLSYM) ||
3073 (obj->versyms[symnum] & VER_NDX_HIDDEN) ||
3074 (verndx >= VER_NDX_GIVEN))
3081 return (vcount == 1) ? vsymp : NULL;
3085 trace_loaded_objects(Obj_Entry *obj)
3087 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3090 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3093 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3094 fmt1 = "\t%o => %p (%x)\n";
3096 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3097 fmt2 = "\t%o (%x)\n";
3099 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL");
3101 for (; obj; obj = obj->next) {
3102 Needed_Entry *needed;
3106 if (list_containers && obj->needed != NULL)
3107 printf("%s:\n", obj->path);
3108 for (needed = obj->needed; needed; needed = needed->next) {
3109 if (needed->obj != NULL) {
3110 if (needed->obj->traced && !list_containers)
3112 needed->obj->traced = true;
3113 path = needed->obj->path;
3117 name = (char *)obj->strtab + needed->name;
3118 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3120 fmt = is_lib ? fmt1 : fmt2;
3121 while ((c = *fmt++) != '\0') {
3147 printf("%s", main_local);
3150 printf("%s", obj_main->path);
3159 printf("%p", needed->obj ? needed->obj->mapbase : 0);
3171 * Unload a dlopened object and its dependencies from memory and from
3172 * our data structures. It is assumed that the DAG rooted in the
3173 * object has already been unreferenced, and that the object has a
3174 * reference count of 0.
3177 unload_object(Obj_Entry *root)
3182 assert(root->refcount == 0);
3185 * Pass over the DAG removing unreferenced objects from
3186 * appropriate lists.
3188 unlink_object(root);
3190 /* Unmap all objects that are no longer referenced. */
3191 linkp = &obj_list->next;
3192 while ((obj = *linkp) != NULL) {
3193 if (obj->refcount == 0) {
3194 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3196 dbg("unloading \"%s\"", obj->path);
3197 munmap(obj->mapbase, obj->mapsize);
3198 linkmap_delete(obj);
3209 unlink_object(Obj_Entry *root)
3213 if (root->refcount == 0) {
3214 /* Remove the object from the RTLD_GLOBAL list. */
3215 objlist_remove(&list_global, root);
3217 /* Remove the object from all objects' DAG lists. */
3218 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3219 objlist_remove(&elm->obj->dldags, root);
3220 if (elm->obj != root)
3221 unlink_object(elm->obj);
3227 ref_dag(Obj_Entry *root)
3231 assert(root->dag_inited);
3232 STAILQ_FOREACH(elm, &root->dagmembers, link)
3233 elm->obj->refcount++;
3237 unref_dag(Obj_Entry *root)
3241 assert(root->dag_inited);
3242 STAILQ_FOREACH(elm, &root->dagmembers, link)
3243 elm->obj->refcount--;
3247 * Common code for MD __tls_get_addr().
3250 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
3252 Elf_Addr* dtv = *dtvp;
3253 RtldLockState lockstate;
3255 /* Check dtv generation in case new modules have arrived */
3256 if (dtv[0] != tls_dtv_generation) {
3260 wlock_acquire(rtld_bind_lock, &lockstate);
3261 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3263 if (to_copy > tls_max_index)
3264 to_copy = tls_max_index;
3265 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
3266 newdtv[0] = tls_dtv_generation;
3267 newdtv[1] = tls_max_index;
3269 lock_release(rtld_bind_lock, &lockstate);
3273 /* Dynamically allocate module TLS if necessary */
3274 if (!dtv[index + 1]) {
3275 /* Signal safe, wlock will block out signals. */
3276 wlock_acquire(rtld_bind_lock, &lockstate);
3277 if (!dtv[index + 1])
3278 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
3279 lock_release(rtld_bind_lock, &lockstate);
3281 return (void*) (dtv[index + 1] + offset);
3284 #if defined(RTLD_STATIC_TLS_VARIANT_II)
3287 * Allocate the static TLS area. Return a pointer to the TCB. The
3288 * static area is based on negative offsets relative to the tcb.
3290 * The TCB contains an errno pointer for the system call layer, but because
3291 * we are the RTLD we really have no idea how the caller was compiled so
3292 * the information has to be passed in. errno can either be:
3294 * type 0 errno is a simple non-TLS global pointer.
3295 * (special case for e.g. libc_rtld)
3296 * type 1 errno accessed by GOT entry (dynamically linked programs)
3297 * type 2 errno accessed by %gs:OFFSET (statically linked programs)
3300 allocate_tls(Obj_Entry *objs)
3305 struct tls_tcb *tcb;
3310 * Allocate the new TCB. static TLS storage is placed just before the
3311 * TCB to support the %gs:OFFSET (negative offset) model.
3313 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
3314 ~RTLD_STATIC_TLS_ALIGN_MASK;
3315 tcb = malloc(data_size + sizeof(*tcb));
3316 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */
3318 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr);
3319 dtv = malloc(dtv_size);
3320 bzero(dtv, dtv_size);
3322 #ifdef RTLD_TCB_HAS_SELF_POINTER
3323 tcb->tcb_self = tcb;
3326 tcb->tcb_pthread = NULL;
3328 dtv[0] = tls_dtv_generation;
3329 dtv[1] = tls_max_index;
3331 for (obj = objs; obj; obj = obj->next) {
3332 if (obj->tlsoffset) {
3333 addr = (Elf_Addr)tcb - obj->tlsoffset;
3334 memset((void *)(addr + obj->tlsinitsize),
3335 0, obj->tlssize - obj->tlsinitsize);
3337 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3338 dtv[obj->tlsindex + 1] = addr;
3345 free_tls(struct tls_tcb *tcb)
3349 Elf_Addr tls_start, tls_end;
3352 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
3353 ~RTLD_STATIC_TLS_ALIGN_MASK;
3357 tls_end = (Elf_Addr)tcb;
3358 tls_start = (Elf_Addr)tcb - data_size;
3359 for (i = 0; i < dtv_size; i++) {
3360 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) {
3361 free((void *)dtv[i+2]);
3365 free((void*) tls_start);
3369 #error "Unsupported TLS layout"
3373 * Allocate TLS block for module with given index.
3376 allocate_module_tls(int index)
3381 for (obj = obj_list; obj; obj = obj->next) {
3382 if (obj->tlsindex == index)
3386 _rtld_error("Can't find module with TLS index %d", index);
3390 p = malloc(obj->tlssize);
3392 _rtld_error("Cannot allocate TLS block for index %d", index);
3395 memcpy(p, obj->tlsinit, obj->tlsinitsize);
3396 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
3402 allocate_tls_offset(Obj_Entry *obj)
3409 if (obj->tlssize == 0) {
3410 obj->tls_done = true;
3414 if (obj->tlsindex == 1)
3415 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
3417 off = calculate_tls_offset(tls_last_offset, tls_last_size,
3418 obj->tlssize, obj->tlsalign);
3421 * If we have already fixed the size of the static TLS block, we
3422 * must stay within that size. When allocating the static TLS, we
3423 * leave a small amount of space spare to be used for dynamically
3424 * loading modules which use static TLS.
3426 if (tls_static_space) {
3427 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
3431 tls_last_offset = obj->tlsoffset = off;
3432 tls_last_size = obj->tlssize;
3433 obj->tls_done = true;
3439 free_tls_offset(Obj_Entry *obj)
3441 #ifdef RTLD_STATIC_TLS_VARIANT_II
3443 * If we were the last thing to allocate out of the static TLS
3444 * block, we give our space back to the 'allocator'. This is a
3445 * simplistic workaround to allow libGL.so.1 to be loaded and
3446 * unloaded multiple times. We only handle the Variant II
3447 * mechanism for now - this really needs a proper allocator.
3449 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
3450 == calculate_tls_end(tls_last_offset, tls_last_size)) {
3451 tls_last_offset -= obj->tlssize;
3458 _rtld_allocate_tls(void)
3460 struct tls_tcb *new_tcb;
3461 RtldLockState lockstate;
3463 wlock_acquire(rtld_bind_lock, &lockstate);
3464 new_tcb = allocate_tls(obj_list);
3465 lock_release(rtld_bind_lock, &lockstate);
3470 _rtld_free_tls(struct tls_tcb *tcb)
3472 RtldLockState lockstate;
3474 wlock_acquire(rtld_bind_lock, &lockstate);
3476 lock_release(rtld_bind_lock, &lockstate);
3480 object_add_name(Obj_Entry *obj, const char *name)
3486 entry = malloc(sizeof(Name_Entry) + len);
3488 if (entry != NULL) {
3489 strcpy(entry->name, name);
3490 STAILQ_INSERT_TAIL(&obj->names, entry, link);
3495 object_match_name(const Obj_Entry *obj, const char *name)
3499 STAILQ_FOREACH(entry, &obj->names, link) {
3500 if (strcmp(name, entry->name) == 0)
3507 locate_dependency(const Obj_Entry *obj, const char *name)
3509 const Objlist_Entry *entry;
3510 const Needed_Entry *needed;
3512 STAILQ_FOREACH(entry, &list_main, link) {
3513 if (object_match_name(entry->obj, name))
3517 for (needed = obj->needed; needed != NULL; needed = needed->next) {
3518 if (strcmp(obj->strtab + needed->name, name) == 0 ||
3519 (needed->obj != NULL && object_match_name(needed->obj, name))) {
3521 * If there is DT_NEEDED for the name we are looking for,
3522 * we are all set. Note that object might not be found if
3523 * dependency was not loaded yet, so the function can
3524 * return NULL here. This is expected and handled
3525 * properly by the caller.
3527 return (needed->obj);
3530 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
3536 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
3537 const Elf_Vernaux *vna)
3539 const Elf_Verdef *vd;
3540 const char *vername;
3542 vername = refobj->strtab + vna->vna_name;
3543 vd = depobj->verdef;
3545 _rtld_error("%s: version %s required by %s not defined",
3546 depobj->path, vername, refobj->path);
3550 if (vd->vd_version != VER_DEF_CURRENT) {
3551 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3552 depobj->path, vd->vd_version);
3555 if (vna->vna_hash == vd->vd_hash) {
3556 const Elf_Verdaux *aux = (const Elf_Verdaux *)
3557 ((char *)vd + vd->vd_aux);
3558 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
3561 if (vd->vd_next == 0)
3563 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3565 if (vna->vna_flags & VER_FLG_WEAK)
3567 _rtld_error("%s: version %s required by %s not found",
3568 depobj->path, vername, refobj->path);
3573 rtld_verify_object_versions(Obj_Entry *obj)
3575 const Elf_Verneed *vn;
3576 const Elf_Verdef *vd;
3577 const Elf_Verdaux *vda;
3578 const Elf_Vernaux *vna;
3579 const Obj_Entry *depobj;
3580 int maxvernum, vernum;
3584 * Walk over defined and required version records and figure out
3585 * max index used by any of them. Do very basic sanity checking
3589 while (vn != NULL) {
3590 if (vn->vn_version != VER_NEED_CURRENT) {
3591 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
3592 obj->path, vn->vn_version);
3595 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3597 vernum = VER_NEED_IDX(vna->vna_other);
3598 if (vernum > maxvernum)
3600 if (vna->vna_next == 0)
3602 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3604 if (vn->vn_next == 0)
3606 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3610 while (vd != NULL) {
3611 if (vd->vd_version != VER_DEF_CURRENT) {
3612 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3613 obj->path, vd->vd_version);
3616 vernum = VER_DEF_IDX(vd->vd_ndx);
3617 if (vernum > maxvernum)
3619 if (vd->vd_next == 0)
3621 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3628 * Store version information in array indexable by version index.
3629 * Verify that object version requirements are satisfied along the
3632 obj->vernum = maxvernum + 1;
3633 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry));
3636 while (vd != NULL) {
3637 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
3638 vernum = VER_DEF_IDX(vd->vd_ndx);
3639 assert(vernum <= maxvernum);
3640 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
3641 obj->vertab[vernum].hash = vd->vd_hash;
3642 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
3643 obj->vertab[vernum].file = NULL;
3644 obj->vertab[vernum].flags = 0;
3646 if (vd->vd_next == 0)
3648 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3652 while (vn != NULL) {
3653 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
3656 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3658 if (check_object_provided_version(obj, depobj, vna))
3660 vernum = VER_NEED_IDX(vna->vna_other);
3661 assert(vernum <= maxvernum);
3662 obj->vertab[vernum].hash = vna->vna_hash;
3663 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
3664 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
3665 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
3666 VER_INFO_HIDDEN : 0;
3667 if (vna->vna_next == 0)
3669 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3671 if (vn->vn_next == 0)
3673 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3679 rtld_verify_versions(const Objlist *objlist)
3681 Objlist_Entry *entry;
3685 STAILQ_FOREACH(entry, objlist, link) {
3687 * Skip dummy objects or objects that have their version requirements
3690 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
3692 if (rtld_verify_object_versions(entry->obj) == -1) {
3694 if (ld_tracing == NULL)
3698 if (rc == 0 || ld_tracing != NULL)
3699 rc = rtld_verify_object_versions(&obj_rtld);
3704 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
3709 vernum = VER_NDX(obj->versyms[symnum]);
3710 if (vernum >= obj->vernum) {
3711 _rtld_error("%s: symbol %s has wrong verneed value %d",
3712 obj->path, obj->strtab + symnum, vernum);
3713 } else if (obj->vertab[vernum].hash != 0) {
3714 return &obj->vertab[vernum];
3721 * No unresolved symbols for rtld.
3724 __pthread_cxa_finalize(struct dl_phdr_info *a)