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 *) __noinline;
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);
1136 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1137 obj->relro_size = round_page(ph->p_memsz);
1142 _rtld_error("%s: too few PT_LOAD segments", path);
1151 dlcheck(void *handle)
1155 for (obj = obj_list; obj != NULL; obj = obj->next)
1156 if (obj == (Obj_Entry *) handle)
1159 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1160 _rtld_error("Invalid shared object handle %p", handle);
1167 * If the given object is already in the donelist, return true. Otherwise
1168 * add the object to the list and return false.
1171 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1175 for (i = 0; i < dlp->num_used; i++)
1176 if (dlp->objs[i] == obj)
1179 * Our donelist allocation should always be sufficient. But if
1180 * our threads locking isn't working properly, more shared objects
1181 * could have been loaded since we allocated the list. That should
1182 * never happen, but we'll handle it properly just in case it does.
1184 if (dlp->num_used < dlp->num_alloc)
1185 dlp->objs[dlp->num_used++] = obj;
1190 * Hash function for symbol table lookup. Don't even think about changing
1191 * this. It is specified by the System V ABI.
1194 elf_hash(const char *name)
1196 const unsigned char *p = (const unsigned char *) name;
1197 unsigned long h = 0;
1200 while (*p != '\0') {
1201 h = (h << 4) + *p++;
1202 if ((g = h & 0xf0000000) != 0)
1210 * Find the library with the given name, and return its full pathname.
1211 * The returned string is dynamically allocated. Generates an error
1212 * message and returns NULL if the library cannot be found.
1214 * If the second argument is non-NULL, then it refers to an already-
1215 * loaded shared object, whose library search path will be searched.
1217 * The search order is:
1219 * rpath in the referencing file
1224 find_library(const char *xname, const Obj_Entry *refobj)
1229 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1230 if (xname[0] != '/' && !trust) {
1231 _rtld_error("Absolute pathname required for shared object \"%s\"",
1235 if (refobj != NULL && refobj->z_origin)
1236 return origin_subst(xname, refobj->origin_path);
1238 return xstrdup(xname);
1241 if (libmap_disable || (refobj == NULL) ||
1242 (name = lm_find(refobj->path, xname)) == NULL)
1243 name = (char *)xname;
1245 dbg(" Searching for \"%s\"", name);
1247 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1249 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1250 (pathname = search_library_path(name, gethints())) != NULL ||
1251 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1254 if(refobj != NULL && refobj->path != NULL) {
1255 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1256 name, basename(refobj->path));
1258 _rtld_error("Shared object \"%s\" not found", name);
1264 * Given a symbol number in a referencing object, find the corresponding
1265 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1266 * no definition was found. Returns a pointer to the Obj_Entry of the
1267 * defining object via the reference parameter DEFOBJ_OUT.
1270 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1271 const Obj_Entry **defobj_out, int flags, SymCache *cache)
1275 const Obj_Entry *defobj;
1276 const Ver_Entry *ventry;
1281 * If we have already found this symbol, get the information from
1284 if (symnum >= refobj->nchains)
1285 return NULL; /* Bad object */
1286 if (cache != NULL && cache[symnum].sym != NULL) {
1287 *defobj_out = cache[symnum].obj;
1288 return cache[symnum].sym;
1291 ref = refobj->symtab + symnum;
1292 name = refobj->strtab + ref->st_name;
1296 * We don't have to do a full scale lookup if the symbol is local.
1297 * We know it will bind to the instance in this load module; to
1298 * which we already have a pointer (ie ref). By not doing a lookup,
1299 * we not only improve performance, but it also avoids unresolvable
1300 * symbols when local symbols are not in the hash table.
1302 * This might occur for TLS module relocations, which simply use
1305 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1306 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1307 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1310 ventry = fetch_ventry(refobj, symnum);
1311 hash = elf_hash(name);
1312 def = symlook_default(name, hash, refobj, &defobj, ventry, flags);
1319 * If we found no definition and the reference is weak, treat the
1320 * symbol as having the value zero.
1322 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1328 *defobj_out = defobj;
1329 /* Record the information in the cache to avoid subsequent lookups. */
1330 if (cache != NULL) {
1331 cache[symnum].sym = def;
1332 cache[symnum].obj = defobj;
1335 if (refobj != &obj_rtld)
1336 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1342 * Return the search path from the ldconfig hints file, reading it if
1343 * necessary. Returns NULL if there are problems with the hints file,
1344 * or if the search path there is empty.
1351 if (hints == NULL) {
1353 struct elfhints_hdr hdr;
1356 /* Keep from trying again in case the hints file is bad. */
1359 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1361 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1362 hdr.magic != ELFHINTS_MAGIC ||
1367 p = xmalloc(hdr.dirlistlen + 1);
1368 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1369 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1377 return hints[0] != '\0' ? hints : NULL;
1381 init_dag(Obj_Entry *root)
1385 if (root->dag_inited)
1387 donelist_init(&donelist);
1388 init_dag1(root, root, &donelist);
1392 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp)
1394 const Needed_Entry *needed;
1396 if (donelist_check(dlp, obj))
1399 objlist_push_tail(&obj->dldags, root);
1400 objlist_push_tail(&root->dagmembers, obj);
1401 for (needed = obj->needed; needed != NULL; needed = needed->next)
1402 if (needed->obj != NULL)
1403 init_dag1(root, needed->obj, dlp);
1404 root->dag_inited = true;
1408 * Initialize the dynamic linker. The argument is the address at which
1409 * the dynamic linker has been mapped into memory. The primary task of
1410 * this function is to relocate the dynamic linker.
1413 init_rtld(caddr_t mapbase)
1415 Obj_Entry objtmp; /* Temporary rtld object */
1418 * Conjure up an Obj_Entry structure for the dynamic linker.
1420 * The "path" member can't be initialized yet because string constants
1421 * cannot yet be accessed. Below we will set it correctly.
1423 memset(&objtmp, 0, sizeof(objtmp));
1426 objtmp.mapbase = mapbase;
1428 objtmp.relocbase = mapbase;
1430 if (RTLD_IS_DYNAMIC()) {
1431 objtmp.dynamic = rtld_dynamic(&objtmp);
1432 digest_dynamic(&objtmp, 1);
1433 assert(objtmp.needed == NULL);
1434 assert(!objtmp.textrel);
1437 * Temporarily put the dynamic linker entry into the object list, so
1438 * that symbols can be found.
1441 relocate_objects(&objtmp, true, &objtmp);
1444 /* Initialize the object list. */
1445 obj_tail = &obj_list;
1447 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1448 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1450 /* Replace the path with a dynamically allocated copy. */
1451 obj_rtld.path = xstrdup(PATH_RTLD);
1453 r_debug.r_brk = r_debug_state;
1454 r_debug.r_state = RT_CONSISTENT;
1458 * Add the init functions from a needed object list (and its recursive
1459 * needed objects) to "list". This is not used directly; it is a helper
1460 * function for initlist_add_objects(). The write lock must be held
1461 * when this function is called.
1464 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1466 /* Recursively process the successor needed objects. */
1467 if (needed->next != NULL)
1468 initlist_add_neededs(needed->next, list);
1470 /* Process the current needed object. */
1471 if (needed->obj != NULL)
1472 initlist_add_objects(needed->obj, &needed->obj->next, list);
1476 * Scan all of the DAGs rooted in the range of objects from "obj" to
1477 * "tail" and add their init functions to "list". This recurses over
1478 * the DAGs and ensure the proper init ordering such that each object's
1479 * needed libraries are initialized before the object itself. At the
1480 * same time, this function adds the objects to the global finalization
1481 * list "list_fini" in the opposite order. The write lock must be
1482 * held when this function is called.
1485 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1487 if (obj->init_scanned || obj->init_done)
1489 obj->init_scanned = true;
1491 /* Recursively process the successor objects. */
1492 if (&obj->next != tail)
1493 initlist_add_objects(obj->next, tail, list);
1495 /* Recursively process the needed objects. */
1496 if (obj->needed != NULL)
1497 initlist_add_neededs(obj->needed, list);
1499 /* Add the object to the init list. */
1500 if (obj->init != (Elf_Addr)NULL)
1501 objlist_push_tail(list, obj);
1503 /* Add the object to the global fini list in the reverse order. */
1504 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) {
1505 objlist_push_head(&list_fini, obj);
1506 obj->on_fini_list = true;
1511 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1515 is_exported(const Elf_Sym *def)
1518 const func_ptr_type *p;
1520 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value);
1521 for (p = exports; *p != NULL; p++)
1522 if (FPTR_TARGET(*p) == value)
1528 * Given a shared object, traverse its list of needed objects, and load
1529 * each of them. Returns 0 on success. Generates an error message and
1530 * returns -1 on failure.
1533 load_needed_objects(Obj_Entry *first, int flags)
1535 Obj_Entry *obj, *obj1;
1537 for (obj = first; obj != NULL; obj = obj->next) {
1538 Needed_Entry *needed;
1540 for (needed = obj->needed; needed != NULL; needed = needed->next) {
1541 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj,
1542 flags & ~RTLD_LO_NOLOAD);
1543 if (obj1 == NULL && !ld_tracing)
1545 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
1546 dbg("obj %s nodelete", obj1->path);
1549 obj1->ref_nodel = true;
1556 #define RTLD_FUNCTRACE "_rtld_functrace"
1559 load_preload_objects(void)
1561 char *p = ld_preload;
1562 static const char delim[] = " \t:;";
1567 p += strspn(p, delim);
1568 while (*p != '\0') {
1569 size_t len = strcspn(p, delim);
1576 obj = load_object(p, NULL, 0);
1578 return -1; /* XXX - cleanup */
1581 p += strspn(p, delim);
1583 /* Check for the magic tracing function */
1584 sym = symlook_obj(RTLD_FUNCTRACE, elf_hash(RTLD_FUNCTRACE), obj, NULL, 1);
1586 rtld_functrace = (void *)(obj->relocbase + sym->st_value);
1587 rtld_functrace_obj = obj;
1590 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
1595 * Load a shared object into memory, if it is not already loaded.
1597 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1601 load_object(const char *name, const Obj_Entry *refobj, int flags)
1608 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1609 if (object_match_name(obj, name))
1612 path = find_library(name, refobj);
1617 * If we didn't find a match by pathname, open the file and check
1618 * again by device and inode. This avoids false mismatches caused
1619 * by multiple links or ".." in pathnames.
1621 * To avoid a race, we open the file and use fstat() rather than
1624 if ((fd = open(path, O_RDONLY)) == -1) {
1625 _rtld_error("Cannot open \"%s\"", path);
1629 if (fstat(fd, &sb) == -1) {
1630 _rtld_error("Cannot fstat \"%s\"", path);
1635 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1636 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
1639 object_add_name(obj, name);
1644 if (flags & RTLD_LO_NOLOAD) {
1650 /* First use of this object, so we must map it in */
1651 obj = do_load_object(fd, name, path, &sb, flags);
1660 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
1667 * but first, make sure that environment variables haven't been
1668 * used to circumvent the noexec flag on a filesystem.
1670 if (dangerous_ld_env) {
1671 if (fstatfs(fd, &fs) != 0) {
1672 _rtld_error("Cannot fstatfs \"%s\"", path);
1675 if (fs.f_flags & MNT_NOEXEC) {
1676 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
1680 dbg("loading \"%s\"", path);
1681 obj = map_object(fd, path, sbp);
1685 object_add_name(obj, name);
1687 digest_dynamic(obj, 0);
1688 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
1690 dbg("refusing to load non-loadable \"%s\"", obj->path);
1691 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
1692 munmap(obj->mapbase, obj->mapsize);
1698 obj_tail = &obj->next;
1701 linkmap_add(obj); /* for GDB & dlinfo() */
1703 dbg(" %p .. %p: %s", obj->mapbase,
1704 obj->mapbase + obj->mapsize - 1, obj->path);
1706 dbg(" WARNING: %s has impure text", obj->path);
1707 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
1714 obj_from_addr(const void *addr)
1718 for (obj = obj_list; obj != NULL; obj = obj->next) {
1719 if (addr < (void *) obj->mapbase)
1721 if (addr < (void *) (obj->mapbase + obj->mapsize))
1728 * Call the finalization functions for each of the objects in "list"
1729 * belonging to the DAG of "root" and referenced once. If NULL "root"
1730 * is specified, every finalization function will be called regardless
1731 * of the reference count and the list elements won't be freed. All of
1732 * the objects are expected to have non-NULL fini functions.
1735 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
1740 assert(root == NULL || root->refcount == 1);
1743 * Preserve the current error message since a fini function might
1744 * call into the dynamic linker and overwrite it.
1746 saved_msg = errmsg_save();
1748 STAILQ_FOREACH(elm, list, link) {
1749 if (root != NULL && (elm->obj->refcount != 1 ||
1750 objlist_find(&root->dagmembers, elm->obj) == NULL))
1752 dbg("calling fini function for %s at %p", elm->obj->path,
1753 (void *)elm->obj->fini);
1754 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0,
1756 /* Remove object from fini list to prevent recursive invocation. */
1757 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1759 * XXX: If a dlopen() call references an object while the
1760 * fini function is in progress, we might end up trying to
1761 * unload the referenced object in dlclose() or the object
1762 * won't be unloaded although its fini function has been
1765 lock_release(rtld_bind_lock, lockstate);
1766 call_initfini_pointer(elm->obj, elm->obj->fini);
1767 wlock_acquire(rtld_bind_lock, lockstate);
1768 /* No need to free anything if process is going down. */
1772 * We must restart the list traversal after every fini call
1773 * because a dlclose() call from the fini function or from
1774 * another thread might have modified the reference counts.
1778 } while (elm != NULL);
1779 errmsg_restore(saved_msg);
1783 * Call the initialization functions for each of the objects in
1784 * "list". All of the objects are expected to have non-NULL init
1788 objlist_call_init(Objlist *list, RtldLockState *lockstate)
1795 * Clean init_scanned flag so that objects can be rechecked and
1796 * possibly initialized earlier if any of vectors called below
1797 * cause the change by using dlopen.
1799 for (obj = obj_list; obj != NULL; obj = obj->next)
1800 obj->init_scanned = false;
1803 * Preserve the current error message since an init function might
1804 * call into the dynamic linker and overwrite it.
1806 saved_msg = errmsg_save();
1807 STAILQ_FOREACH(elm, list, link) {
1808 if (elm->obj->init_done) /* Initialized early. */
1810 dbg("calling init function for %s at %p", elm->obj->path,
1811 (void *)elm->obj->init);
1812 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0,
1815 * Race: other thread might try to use this object before current
1816 * one completes the initilization. Not much can be done here
1817 * without better locking.
1819 elm->obj->init_done = true;
1820 lock_release(rtld_bind_lock, lockstate);
1821 call_initfini_pointer(elm->obj, elm->obj->init);
1822 wlock_acquire(rtld_bind_lock, lockstate);
1824 errmsg_restore(saved_msg);
1828 objlist_clear(Objlist *list)
1832 while (!STAILQ_EMPTY(list)) {
1833 elm = STAILQ_FIRST(list);
1834 STAILQ_REMOVE_HEAD(list, link);
1839 static Objlist_Entry *
1840 objlist_find(Objlist *list, const Obj_Entry *obj)
1844 STAILQ_FOREACH(elm, list, link)
1845 if (elm->obj == obj)
1851 objlist_init(Objlist *list)
1857 objlist_push_head(Objlist *list, Obj_Entry *obj)
1861 elm = NEW(Objlist_Entry);
1863 STAILQ_INSERT_HEAD(list, elm, link);
1867 objlist_push_tail(Objlist *list, Obj_Entry *obj)
1871 elm = NEW(Objlist_Entry);
1873 STAILQ_INSERT_TAIL(list, elm, link);
1877 objlist_remove(Objlist *list, Obj_Entry *obj)
1881 if ((elm = objlist_find(list, obj)) != NULL) {
1882 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1888 * Relocate newly-loaded shared objects. The argument is a pointer to
1889 * the Obj_Entry for the first such object. All objects from the first
1890 * to the end of the list of objects are relocated. Returns 0 on success,
1894 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj)
1898 for (obj = first; obj != NULL; obj = obj->next) {
1900 dbg("relocating \"%s\"", obj->path);
1901 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
1902 obj->symtab == NULL || obj->strtab == NULL) {
1903 _rtld_error("%s: Shared object has no run-time symbol table",
1909 /* There are relocations to the write-protected text segment. */
1910 if (mprotect(obj->mapbase, obj->textsize,
1911 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
1912 _rtld_error("%s: Cannot write-enable text segment: %s",
1913 obj->path, strerror(errno));
1918 /* Process the non-PLT relocations. */
1919 if (reloc_non_plt(obj, rtldobj))
1923 * Reprotect the text segment. Make sure it is included in the
1924 * core dump since we modified it. This unfortunately causes the
1925 * entire text segment to core-out but we don't have much of a
1926 * choice. We could try to only reenable core dumps on pages
1927 * in which relocations occured but that is likely most of the text
1928 * pages anyway, and even that would not work because the rest of
1929 * the text pages would wind up as a read-only OBJT_DEFAULT object
1930 * (created due to our modifications) backed by the original OBJT_VNODE
1931 * object, and the ELF coredump code is currently only able to dump
1932 * vnode records for pure vnode-backed mappings, not vnode backings
1933 * to memory objects.
1936 madvise(obj->mapbase, obj->textsize, MADV_CORE);
1937 if (mprotect(obj->mapbase, obj->textsize,
1938 PROT_READ|PROT_EXEC) == -1) {
1939 _rtld_error("%s: Cannot write-protect text segment: %s",
1940 obj->path, strerror(errno));
1945 /* Process the PLT relocations. */
1946 if (reloc_plt(obj) == -1)
1948 /* Relocate the jump slots if we are doing immediate binding. */
1949 if (obj->bind_now || bind_now)
1950 if (reloc_jmpslots(obj) == -1)
1953 /* Set the special PLT or GOT entries. */
1957 * Set up the magic number and version in the Obj_Entry. These
1958 * were checked in the crt1.o from the original ElfKit, so we
1959 * set them for backward compatibility.
1961 obj->magic = RTLD_MAGIC;
1962 obj->version = RTLD_VERSION;
1965 * Set relocated data to read-only status if protection specified
1968 if (obj->relro_size) {
1969 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
1970 _rtld_error("%s: Cannot enforce relro relocation: %s",
1971 obj->path, strerror(errno));
1981 * Cleanup procedure. It will be called (by the atexit mechanism) just
1982 * before the process exits.
1987 RtldLockState lockstate;
1989 wlock_acquire(rtld_bind_lock, &lockstate);
1991 objlist_call_fini(&list_fini, NULL, &lockstate);
1992 /* No need to remove the items from the list, since we are exiting. */
1993 if (!libmap_disable)
1995 lock_release(rtld_bind_lock, &lockstate);
1999 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2004 path += strspn(path, ":;");
2005 while (*path != '\0') {
2009 len = strcspn(path, ":;");
2010 res = callback(path, len, arg);
2016 path += strspn(path, ":;");
2022 struct try_library_args {
2030 try_library_path(const char *dir, size_t dirlen, void *param)
2032 struct try_library_args *arg;
2035 if (*dir == '/' || trust) {
2038 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2041 pathname = arg->buffer;
2042 strncpy(pathname, dir, dirlen);
2043 pathname[dirlen] = '/';
2044 strcpy(pathname + dirlen + 1, arg->name);
2046 dbg(" Trying \"%s\"", pathname);
2047 if (access(pathname, F_OK) == 0) { /* We found it */
2048 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2049 strcpy(pathname, arg->buffer);
2057 search_library_path(const char *name, const char *path)
2060 struct try_library_args arg;
2066 arg.namelen = strlen(name);
2067 arg.buffer = xmalloc(PATH_MAX);
2068 arg.buflen = PATH_MAX;
2070 p = path_enumerate(path, try_library_path, &arg);
2078 dlclose(void *handle)
2081 RtldLockState lockstate;
2083 wlock_acquire(rtld_bind_lock, &lockstate);
2084 root = dlcheck(handle);
2086 lock_release(rtld_bind_lock, &lockstate);
2089 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2092 /* Unreference the object and its dependencies. */
2093 root->dl_refcount--;
2095 if (root->refcount == 1) {
2097 * The object will be no longer referenced, so we must unload it.
2098 * First, call the fini functions.
2100 objlist_call_fini(&list_fini, root, &lockstate);
2104 /* Finish cleaning up the newly-unreferenced objects. */
2105 GDB_STATE(RT_DELETE,&root->linkmap);
2106 unload_object(root);
2107 GDB_STATE(RT_CONSISTENT,NULL);
2111 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2112 lock_release(rtld_bind_lock, &lockstate);
2119 char *msg = error_message;
2120 error_message = NULL;
2125 dlopen(const char *name, int mode)
2127 Obj_Entry **old_obj_tail;
2130 RtldLockState lockstate;
2131 int result, lo_flags;
2133 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2134 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2135 if (ld_tracing != NULL)
2136 environ = (char **)*get_program_var_addr("environ");
2137 lo_flags = RTLD_LO_DLOPEN;
2138 if (mode & RTLD_NODELETE)
2139 lo_flags |= RTLD_LO_NODELETE;
2140 if (mode & RTLD_NOLOAD)
2141 lo_flags |= RTLD_LO_NOLOAD;
2142 if (ld_tracing != NULL)
2143 lo_flags |= RTLD_LO_TRACE;
2145 objlist_init(&initlist);
2147 wlock_acquire(rtld_bind_lock, &lockstate);
2148 GDB_STATE(RT_ADD,NULL);
2150 old_obj_tail = obj_tail;
2156 obj = load_object(name, obj_main, lo_flags);
2161 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2162 objlist_push_tail(&list_global, obj);
2163 mode &= RTLD_MODEMASK;
2164 if (*old_obj_tail != NULL) { /* We loaded something new. */
2165 assert(*old_obj_tail == obj);
2166 result = load_needed_objects(obj, RTLD_LO_DLOPEN);
2170 result = rtld_verify_versions(&obj->dagmembers);
2171 if (result != -1 && ld_tracing)
2174 (relocate_objects(obj, mode == RTLD_NOW, &obj_rtld)) == -1) {
2177 if (obj->refcount == 0)
2181 /* Make list of init functions to call. */
2182 initlist_add_objects(obj, &obj->next, &initlist);
2187 * Bump the reference counts for objects on this DAG. If
2188 * this is the first dlopen() call for the object that was
2189 * already loaded as a dependency, initialize the dag
2195 if ((lo_flags & RTLD_LO_TRACE) != 0)
2198 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2199 obj->z_nodelete) && !obj->ref_nodel) {
2200 dbg("obj %s nodelete", obj->path);
2202 obj->z_nodelete = obj->ref_nodel = true;
2206 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2208 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2210 /* Call the init functions. */
2211 objlist_call_init(&initlist, &lockstate);
2212 objlist_clear(&initlist);
2213 lock_release(rtld_bind_lock, &lockstate);
2216 trace_loaded_objects(obj);
2217 lock_release(rtld_bind_lock, &lockstate);
2222 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2226 const Obj_Entry *obj, *defobj;
2227 const Elf_Sym *def, *symp;
2229 RtldLockState lockstate;
2231 hash = elf_hash(name);
2234 flags |= SYMLOOK_IN_PLT;
2236 rlock_acquire(rtld_bind_lock, &lockstate);
2237 if (sigsetjmp(lockstate.env, 0) != 0)
2238 lock_upgrade(rtld_bind_lock, &lockstate);
2239 if (handle == NULL || handle == RTLD_NEXT ||
2240 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2242 if ((obj = obj_from_addr(retaddr)) == NULL) {
2243 _rtld_error("Cannot determine caller's shared object");
2244 lock_release(rtld_bind_lock, &lockstate);
2247 if (handle == NULL) { /* Just the caller's shared object. */
2248 def = symlook_obj(name, hash, obj, ve, flags);
2250 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2251 handle == RTLD_SELF) { /* ... caller included */
2252 if (handle == RTLD_NEXT)
2254 for (; obj != NULL; obj = obj->next) {
2255 if ((symp = symlook_obj(name, hash, obj, ve, flags)) != NULL) {
2256 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) {
2259 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2265 * Search the dynamic linker itself, and possibly resolve the
2266 * symbol from there. This is how the application links to
2267 * dynamic linker services such as dlopen.
2269 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2270 symp = symlook_obj(name, hash, &obj_rtld, ve, flags);
2277 assert(handle == RTLD_DEFAULT);
2278 def = symlook_default(name, hash, obj, &defobj, ve, flags);
2281 if ((obj = dlcheck(handle)) == NULL) {
2282 lock_release(rtld_bind_lock, &lockstate);
2286 donelist_init(&donelist);
2287 if (obj->mainprog) {
2288 /* Search main program and all libraries loaded by it. */
2289 def = symlook_list(name, hash, &list_main, &defobj, ve, flags,
2293 * We do not distinguish between 'main' object and global scope.
2294 * If symbol is not defined by objects loaded at startup, continue
2295 * search among dynamically loaded objects with RTLD_GLOBAL
2299 def = symlook_list(name, hash, &list_global, &defobj, ve,
2304 /* Search the whole DAG rooted at the given object. */
2306 fake.obj = (Obj_Entry *)obj;
2308 def = symlook_needed(name, hash, &fake, &defobj, ve, flags,
2314 lock_release(rtld_bind_lock, &lockstate);
2317 * The value required by the caller is derived from the value
2318 * of the symbol. For the ia64 architecture, we need to
2319 * construct a function descriptor which the caller can use to
2320 * call the function with the right 'gp' value. For other
2321 * architectures and for non-functions, the value is simply
2322 * the relocated value of the symbol.
2324 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
2325 return (make_function_pointer(def, defobj));
2327 return (defobj->relocbase + def->st_value);
2330 _rtld_error("Undefined symbol \"%s\"", name);
2331 lock_release(rtld_bind_lock, &lockstate);
2336 dlsym(void *handle, const char *name)
2338 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2343 dlfunc(void *handle, const char *name)
2350 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
2356 dlvsym(void *handle, const char *name, const char *version)
2360 ventry.name = version;
2362 ventry.hash = elf_hash(version);
2364 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2369 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
2371 const Obj_Entry *obj;
2372 RtldLockState lockstate;
2374 rlock_acquire(rtld_bind_lock, &lockstate);
2375 obj = obj_from_addr(addr);
2377 _rtld_error("No shared object contains address");
2378 lock_release(rtld_bind_lock, &lockstate);
2381 rtld_fill_dl_phdr_info(obj, phdr_info);
2382 lock_release(rtld_bind_lock, &lockstate);
2387 dladdr(const void *addr, Dl_info *info)
2389 const Obj_Entry *obj;
2392 unsigned long symoffset;
2393 RtldLockState lockstate;
2395 rlock_acquire(rtld_bind_lock, &lockstate);
2396 obj = obj_from_addr(addr);
2398 _rtld_error("No shared object contains address");
2399 lock_release(rtld_bind_lock, &lockstate);
2402 info->dli_fname = obj->path;
2403 info->dli_fbase = obj->mapbase;
2404 info->dli_saddr = NULL;
2405 info->dli_sname = NULL;
2408 * Walk the symbol list looking for the symbol whose address is
2409 * closest to the address sent in.
2411 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
2412 def = obj->symtab + symoffset;
2415 * For skip the symbol if st_shndx is either SHN_UNDEF or
2418 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2422 * If the symbol is greater than the specified address, or if it
2423 * is further away from addr than the current nearest symbol,
2426 symbol_addr = obj->relocbase + def->st_value;
2427 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2430 /* Update our idea of the nearest symbol. */
2431 info->dli_sname = obj->strtab + def->st_name;
2432 info->dli_saddr = symbol_addr;
2435 if (info->dli_saddr == addr)
2438 lock_release(rtld_bind_lock, &lockstate);
2443 dlinfo(void *handle, int request, void *p)
2445 const Obj_Entry *obj;
2446 RtldLockState lockstate;
2449 rlock_acquire(rtld_bind_lock, &lockstate);
2451 if (handle == NULL || handle == RTLD_SELF) {
2454 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2455 if ((obj = obj_from_addr(retaddr)) == NULL)
2456 _rtld_error("Cannot determine caller's shared object");
2458 obj = dlcheck(handle);
2461 lock_release(rtld_bind_lock, &lockstate);
2467 case RTLD_DI_LINKMAP:
2468 *((struct link_map const **)p) = &obj->linkmap;
2470 case RTLD_DI_ORIGIN:
2471 error = rtld_dirname(obj->path, p);
2474 case RTLD_DI_SERINFOSIZE:
2475 case RTLD_DI_SERINFO:
2476 error = do_search_info(obj, request, (struct dl_serinfo *)p);
2480 _rtld_error("Invalid request %d passed to dlinfo()", request);
2484 lock_release(rtld_bind_lock, &lockstate);
2490 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
2493 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
2494 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
2495 STAILQ_FIRST(&obj->names)->name : obj->path;
2496 phdr_info->dlpi_phdr = obj->phdr;
2497 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
2498 phdr_info->dlpi_tls_modid = obj->tlsindex;
2499 phdr_info->dlpi_tls_data = obj->tlsinit;
2500 phdr_info->dlpi_adds = obj_loads;
2501 phdr_info->dlpi_subs = obj_loads - obj_count;
2505 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
2507 struct dl_phdr_info phdr_info;
2508 const Obj_Entry *obj;
2509 RtldLockState bind_lockstate, phdr_lockstate;
2512 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
2513 rlock_acquire(rtld_bind_lock, &bind_lockstate);
2517 for (obj = obj_list; obj != NULL; obj = obj->next) {
2518 rtld_fill_dl_phdr_info(obj, &phdr_info);
2519 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
2523 lock_release(rtld_bind_lock, &bind_lockstate);
2524 lock_release(rtld_phdr_lock, &phdr_lockstate);
2529 struct fill_search_info_args {
2532 Dl_serinfo *serinfo;
2533 Dl_serpath *serpath;
2538 fill_search_info(const char *dir, size_t dirlen, void *param)
2540 struct fill_search_info_args *arg;
2544 if (arg->request == RTLD_DI_SERINFOSIZE) {
2545 arg->serinfo->dls_cnt ++;
2546 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
2548 struct dl_serpath *s_entry;
2550 s_entry = arg->serpath;
2551 s_entry->dls_name = arg->strspace;
2552 s_entry->dls_flags = arg->flags;
2554 strncpy(arg->strspace, dir, dirlen);
2555 arg->strspace[dirlen] = '\0';
2557 arg->strspace += dirlen + 1;
2565 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2567 struct dl_serinfo _info;
2568 struct fill_search_info_args args;
2570 args.request = RTLD_DI_SERINFOSIZE;
2571 args.serinfo = &_info;
2573 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2576 path_enumerate(ld_library_path, fill_search_info, &args);
2577 path_enumerate(obj->rpath, fill_search_info, &args);
2578 path_enumerate(gethints(), fill_search_info, &args);
2579 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
2582 if (request == RTLD_DI_SERINFOSIZE) {
2583 info->dls_size = _info.dls_size;
2584 info->dls_cnt = _info.dls_cnt;
2588 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
2589 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
2593 args.request = RTLD_DI_SERINFO;
2594 args.serinfo = info;
2595 args.serpath = &info->dls_serpath[0];
2596 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
2598 args.flags = LA_SER_LIBPATH;
2599 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
2602 args.flags = LA_SER_RUNPATH;
2603 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
2606 args.flags = LA_SER_CONFIG;
2607 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
2610 args.flags = LA_SER_DEFAULT;
2611 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
2617 rtld_dirname(const char *path, char *bname)
2621 /* Empty or NULL string gets treated as "." */
2622 if (path == NULL || *path == '\0') {
2628 /* Strip trailing slashes */
2629 endp = path + strlen(path) - 1;
2630 while (endp > path && *endp == '/')
2633 /* Find the start of the dir */
2634 while (endp > path && *endp != '/')
2637 /* Either the dir is "/" or there are no slashes */
2639 bname[0] = *endp == '/' ? '/' : '.';
2645 } while (endp > path && *endp == '/');
2648 if (endp - path + 2 > PATH_MAX)
2650 _rtld_error("Filename is too long: %s", path);
2654 strncpy(bname, path, endp - path + 1);
2655 bname[endp - path + 1] = '\0';
2660 rtld_dirname_abs(const char *path, char *base)
2662 char base_rel[PATH_MAX];
2664 if (rtld_dirname(path, base) == -1)
2668 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
2669 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
2670 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
2672 strcpy(base, base_rel);
2677 linkmap_add(Obj_Entry *obj)
2679 struct link_map *l = &obj->linkmap;
2680 struct link_map *prev;
2682 obj->linkmap.l_name = obj->path;
2683 obj->linkmap.l_addr = obj->mapbase;
2684 obj->linkmap.l_ld = obj->dynamic;
2686 /* GDB needs load offset on MIPS to use the symbols */
2687 obj->linkmap.l_offs = obj->relocbase;
2690 if (r_debug.r_map == NULL) {
2696 * Scan to the end of the list, but not past the entry for the
2697 * dynamic linker, which we want to keep at the very end.
2699 for (prev = r_debug.r_map;
2700 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
2701 prev = prev->l_next)
2704 /* Link in the new entry. */
2706 l->l_next = prev->l_next;
2707 if (l->l_next != NULL)
2708 l->l_next->l_prev = l;
2713 linkmap_delete(Obj_Entry *obj)
2715 struct link_map *l = &obj->linkmap;
2717 if (l->l_prev == NULL) {
2718 if ((r_debug.r_map = l->l_next) != NULL)
2719 l->l_next->l_prev = NULL;
2723 if ((l->l_prev->l_next = l->l_next) != NULL)
2724 l->l_next->l_prev = l->l_prev;
2728 * Function for the debugger to set a breakpoint on to gain control.
2730 * The two parameters allow the debugger to easily find and determine
2731 * what the runtime loader is doing and to whom it is doing it.
2733 * When the loadhook trap is hit (r_debug_state, set at program
2734 * initialization), the arguments can be found on the stack:
2736 * +8 struct link_map *m
2737 * +4 struct r_debug *rd
2741 r_debug_state(struct r_debug* rd, struct link_map *m)
2744 * The following is a hack to force the compiler to emit calls to
2745 * this function, even when optimizing. If the function is empty,
2746 * the compiler is not obliged to emit any code for calls to it,
2747 * even when marked __noinline. However, gdb depends on those
2750 __asm __volatile("" : : : "memory");
2754 * Get address of the pointer variable in the main program.
2756 static const void **
2757 get_program_var_addr(const char *name)
2759 const Obj_Entry *obj;
2762 hash = elf_hash(name);
2763 for (obj = obj_main; obj != NULL; obj = obj->next) {
2766 if ((def = symlook_obj(name, hash, obj, NULL, 0)) != NULL) {
2769 addr = (const void **)(obj->relocbase + def->st_value);
2777 * Set a pointer variable in the main program to the given value. This
2778 * is used to set key variables such as "environ" before any of the
2779 * init functions are called.
2782 set_program_var(const char *name, const void *value)
2786 if ((addr = get_program_var_addr(name)) != NULL) {
2787 dbg("\"%s\": *%p <-- %p", name, addr, value);
2793 * This is a special version of getenv which is far more efficient
2794 * at finding LD_ environment vars.
2798 _getenv_ld(const char *id)
2802 int idlen = strlen(id);
2804 if (ld_index == LD_ARY_CACHE)
2806 if (ld_index == 0) {
2807 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) {
2808 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_')
2815 for (i = ld_index - 1; i >= 0; --i) {
2816 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=')
2817 return(ld_ary[i] + idlen + 1);
2823 * Given a symbol name in a referencing object, find the corresponding
2824 * definition of the symbol. Returns a pointer to the symbol, or NULL if
2825 * no definition was found. Returns a pointer to the Obj_Entry of the
2826 * defining object via the reference parameter DEFOBJ_OUT.
2828 static const Elf_Sym *
2829 symlook_default(const char *name, unsigned long hash, const Obj_Entry *refobj,
2830 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags)
2834 const Elf_Sym *symp;
2835 const Obj_Entry *obj;
2836 const Obj_Entry *defobj;
2837 const Objlist_Entry *elm;
2840 donelist_init(&donelist);
2842 /* Look first in the referencing object if linked symbolically. */
2843 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
2844 symp = symlook_obj(name, hash, refobj, ventry, flags);
2851 /* Search all objects loaded at program start up. */
2852 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2853 symp = symlook_list(name, hash, &list_main, &obj, ventry, flags,
2856 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2862 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
2863 STAILQ_FOREACH(elm, &list_global, link) {
2864 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
2866 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry,
2869 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2875 /* Search all dlopened DAGs containing the referencing object. */
2876 STAILQ_FOREACH(elm, &refobj->dldags, link) {
2877 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
2879 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, ventry,
2882 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2889 * Search the dynamic linker itself, and possibly resolve the
2890 * symbol from there. This is how the application links to
2891 * dynamic linker services such as dlopen. Only the values listed
2892 * in the "exports" array can be resolved from the dynamic linker.
2894 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2895 symp = symlook_obj(name, hash, &obj_rtld, ventry, flags);
2896 if (symp != NULL && is_exported(symp)) {
2903 *defobj_out = defobj;
2907 static const Elf_Sym *
2908 symlook_list(const char *name, unsigned long hash, const Objlist *objlist,
2909 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags,
2912 const Elf_Sym *symp;
2914 const Obj_Entry *defobj;
2915 const Objlist_Entry *elm;
2919 STAILQ_FOREACH(elm, objlist, link) {
2920 if (donelist_check(dlp, elm->obj))
2922 if ((symp = symlook_obj(name, hash, elm->obj, ventry, flags)) != NULL) {
2923 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) {
2926 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2932 *defobj_out = defobj;
2937 * Search the symbol table of a shared object and all objects needed
2938 * by it for a symbol of the given name. Search order is
2939 * breadth-first. Returns a pointer to the symbol, or NULL if no
2940 * definition was found.
2942 static const Elf_Sym *
2943 symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed,
2944 const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags,
2947 const Elf_Sym *def, *def_w;
2948 const Needed_Entry *n;
2949 const Obj_Entry *obj, *defobj, *defobj1;
2953 for (n = needed; n != NULL; n = n->next) {
2954 if ((obj = n->obj) == NULL ||
2955 donelist_check(dlp, obj) ||
2956 (def = symlook_obj(name, hash, obj, ventry, flags)) == NULL)
2959 if (ELF_ST_BIND(def->st_info) != STB_WEAK) {
2960 *defobj_out = defobj;
2965 * There we come when either symbol definition is not found in
2966 * directly needed objects, or found symbol is weak.
2968 for (n = needed; n != NULL; n = n->next) {
2969 if ((obj = n->obj) == NULL)
2971 def_w = symlook_needed(name, hash, obj->needed, &defobj1,
2972 ventry, flags, dlp);
2975 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) {
2979 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK)
2983 *defobj_out = defobj;
2988 * Search the symbol table of a single shared object for a symbol of
2989 * the given name and version, if requested. Returns a pointer to the
2990 * symbol, or NULL if no definition was found.
2992 * The symbol's hash value is passed in for efficiency reasons; that
2993 * eliminates many recomputations of the hash value.
2996 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj,
2997 const Ver_Entry *ventry, int flags)
2999 unsigned long symnum;
3000 const Elf_Sym *vsymp;
3004 if (obj->buckets == NULL)
3009 symnum = obj->buckets[hash % obj->nbuckets];
3011 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3012 const Elf_Sym *symp;
3015 if (symnum >= obj->nchains)
3016 return NULL; /* Bad object */
3018 symp = obj->symtab + symnum;
3019 strp = obj->strtab + symp->st_name;
3021 switch (ELF_ST_TYPE(symp->st_info)) {
3025 if (symp->st_value == 0)
3029 if (symp->st_shndx != SHN_UNDEF)
3031 else if (((flags & SYMLOOK_IN_PLT) == 0) &&
3032 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3038 if (name[0] != strp[0] || strcmp(name, strp) != 0)
3041 if (ventry == NULL) {
3042 if (obj->versyms != NULL) {
3043 verndx = VER_NDX(obj->versyms[symnum]);
3044 if (verndx > obj->vernum) {
3045 _rtld_error("%s: symbol %s references wrong version %d",
3046 obj->path, obj->strtab + symnum, verndx);
3050 * If we are not called from dlsym (i.e. this is a normal
3051 * relocation from unversioned binary), accept the symbol
3052 * immediately if it happens to have first version after
3053 * this shared object became versioned. Otherwise, if
3054 * symbol is versioned and not hidden, remember it. If it
3055 * is the only symbol with this name exported by the
3056 * shared object, it will be returned as a match at the
3057 * end of the function. If symbol is global (verndx < 2)
3058 * accept it unconditionally.
3060 if ((flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN)
3062 else if (verndx >= VER_NDX_GIVEN) {
3063 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
3073 if (obj->versyms == NULL) {
3074 if (object_match_name(obj, ventry->name)) {
3075 _rtld_error("%s: object %s should provide version %s for "
3076 "symbol %s", obj_rtld.path, obj->path, ventry->name,
3077 obj->strtab + symnum);
3081 verndx = VER_NDX(obj->versyms[symnum]);
3082 if (verndx > obj->vernum) {
3083 _rtld_error("%s: symbol %s references wrong version %d",
3084 obj->path, obj->strtab + symnum, verndx);
3087 if (obj->vertab[verndx].hash != ventry->hash ||
3088 strcmp(obj->vertab[verndx].name, ventry->name)) {
3090 * Version does not match. Look if this is a global symbol
3091 * and if it is not hidden. If global symbol (verndx < 2)
3092 * is available, use it. Do not return symbol if we are
3093 * called by dlvsym, because dlvsym looks for a specific
3094 * version and default one is not what dlvsym wants.
3096 if ((flags & SYMLOOK_DLSYM) ||
3097 (obj->versyms[symnum] & VER_NDX_HIDDEN) ||
3098 (verndx >= VER_NDX_GIVEN))
3105 return (vcount == 1) ? vsymp : NULL;
3109 trace_loaded_objects(Obj_Entry *obj)
3111 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3114 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3117 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3118 fmt1 = "\t%o => %p (%x)\n";
3120 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3121 fmt2 = "\t%o (%x)\n";
3123 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL");
3125 for (; obj; obj = obj->next) {
3126 Needed_Entry *needed;
3130 if (list_containers && obj->needed != NULL)
3131 printf("%s:\n", obj->path);
3132 for (needed = obj->needed; needed; needed = needed->next) {
3133 if (needed->obj != NULL) {
3134 if (needed->obj->traced && !list_containers)
3136 needed->obj->traced = true;
3137 path = needed->obj->path;
3141 name = (char *)obj->strtab + needed->name;
3142 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3144 fmt = is_lib ? fmt1 : fmt2;
3145 while ((c = *fmt++) != '\0') {
3171 printf("%s", main_local);
3174 printf("%s", obj_main->path);
3183 printf("%p", needed->obj ? needed->obj->mapbase : 0);
3195 * Unload a dlopened object and its dependencies from memory and from
3196 * our data structures. It is assumed that the DAG rooted in the
3197 * object has already been unreferenced, and that the object has a
3198 * reference count of 0.
3201 unload_object(Obj_Entry *root)
3206 assert(root->refcount == 0);
3209 * Pass over the DAG removing unreferenced objects from
3210 * appropriate lists.
3212 unlink_object(root);
3214 /* Unmap all objects that are no longer referenced. */
3215 linkp = &obj_list->next;
3216 while ((obj = *linkp) != NULL) {
3217 if (obj->refcount == 0) {
3218 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3220 dbg("unloading \"%s\"", obj->path);
3221 munmap(obj->mapbase, obj->mapsize);
3222 linkmap_delete(obj);
3233 unlink_object(Obj_Entry *root)
3237 if (root->refcount == 0) {
3238 /* Remove the object from the RTLD_GLOBAL list. */
3239 objlist_remove(&list_global, root);
3241 /* Remove the object from all objects' DAG lists. */
3242 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3243 objlist_remove(&elm->obj->dldags, root);
3244 if (elm->obj != root)
3245 unlink_object(elm->obj);
3251 ref_dag(Obj_Entry *root)
3255 assert(root->dag_inited);
3256 STAILQ_FOREACH(elm, &root->dagmembers, link)
3257 elm->obj->refcount++;
3261 unref_dag(Obj_Entry *root)
3265 assert(root->dag_inited);
3266 STAILQ_FOREACH(elm, &root->dagmembers, link)
3267 elm->obj->refcount--;
3271 * Common code for MD __tls_get_addr().
3274 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
3276 Elf_Addr* dtv = *dtvp;
3277 RtldLockState lockstate;
3279 /* Check dtv generation in case new modules have arrived */
3280 if (dtv[0] != tls_dtv_generation) {
3284 wlock_acquire(rtld_bind_lock, &lockstate);
3285 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3287 if (to_copy > tls_max_index)
3288 to_copy = tls_max_index;
3289 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
3290 newdtv[0] = tls_dtv_generation;
3291 newdtv[1] = tls_max_index;
3293 lock_release(rtld_bind_lock, &lockstate);
3294 dtv = *dtvp = newdtv;
3297 /* Dynamically allocate module TLS if necessary */
3298 if (!dtv[index + 1]) {
3299 /* Signal safe, wlock will block out signals. */
3300 wlock_acquire(rtld_bind_lock, &lockstate);
3301 if (!dtv[index + 1])
3302 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
3303 lock_release(rtld_bind_lock, &lockstate);
3305 return (void*) (dtv[index + 1] + offset);
3308 #if defined(RTLD_STATIC_TLS_VARIANT_II)
3311 * Allocate the static TLS area. Return a pointer to the TCB. The
3312 * static area is based on negative offsets relative to the tcb.
3314 * The TCB contains an errno pointer for the system call layer, but because
3315 * we are the RTLD we really have no idea how the caller was compiled so
3316 * the information has to be passed in. errno can either be:
3318 * type 0 errno is a simple non-TLS global pointer.
3319 * (special case for e.g. libc_rtld)
3320 * type 1 errno accessed by GOT entry (dynamically linked programs)
3321 * type 2 errno accessed by %gs:OFFSET (statically linked programs)
3324 allocate_tls(Obj_Entry *objs)
3329 struct tls_tcb *tcb;
3334 * Allocate the new TCB. static TLS storage is placed just before the
3335 * TCB to support the %gs:OFFSET (negative offset) model.
3337 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
3338 ~RTLD_STATIC_TLS_ALIGN_MASK;
3339 tcb = malloc(data_size + sizeof(*tcb));
3340 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */
3342 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr);
3343 dtv = malloc(dtv_size);
3344 bzero(dtv, dtv_size);
3346 #ifdef RTLD_TCB_HAS_SELF_POINTER
3347 tcb->tcb_self = tcb;
3350 tcb->tcb_pthread = NULL;
3352 dtv[0] = tls_dtv_generation;
3353 dtv[1] = tls_max_index;
3355 for (obj = objs; obj; obj = obj->next) {
3356 if (obj->tlsoffset) {
3357 addr = (Elf_Addr)tcb - obj->tlsoffset;
3358 memset((void *)(addr + obj->tlsinitsize),
3359 0, obj->tlssize - obj->tlsinitsize);
3361 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3362 dtv[obj->tlsindex + 1] = addr;
3369 free_tls(struct tls_tcb *tcb)
3373 Elf_Addr tls_start, tls_end;
3376 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
3377 ~RTLD_STATIC_TLS_ALIGN_MASK;
3381 tls_end = (Elf_Addr)tcb;
3382 tls_start = (Elf_Addr)tcb - data_size;
3383 for (i = 0; i < dtv_size; i++) {
3384 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) {
3385 free((void *)dtv[i+2]);
3389 free((void*) tls_start);
3393 #error "Unsupported TLS layout"
3397 * Allocate TLS block for module with given index.
3400 allocate_module_tls(int index)
3405 for (obj = obj_list; obj; obj = obj->next) {
3406 if (obj->tlsindex == index)
3410 _rtld_error("Can't find module with TLS index %d", index);
3414 p = malloc(obj->tlssize);
3416 _rtld_error("Cannot allocate TLS block for index %d", index);
3419 memcpy(p, obj->tlsinit, obj->tlsinitsize);
3420 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
3426 allocate_tls_offset(Obj_Entry *obj)
3433 if (obj->tlssize == 0) {
3434 obj->tls_done = true;
3438 if (obj->tlsindex == 1)
3439 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
3441 off = calculate_tls_offset(tls_last_offset, tls_last_size,
3442 obj->tlssize, obj->tlsalign);
3445 * If we have already fixed the size of the static TLS block, we
3446 * must stay within that size. When allocating the static TLS, we
3447 * leave a small amount of space spare to be used for dynamically
3448 * loading modules which use static TLS.
3450 if (tls_static_space) {
3451 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
3455 tls_last_offset = obj->tlsoffset = off;
3456 tls_last_size = obj->tlssize;
3457 obj->tls_done = true;
3463 free_tls_offset(Obj_Entry *obj)
3465 #ifdef RTLD_STATIC_TLS_VARIANT_II
3467 * If we were the last thing to allocate out of the static TLS
3468 * block, we give our space back to the 'allocator'. This is a
3469 * simplistic workaround to allow libGL.so.1 to be loaded and
3470 * unloaded multiple times. We only handle the Variant II
3471 * mechanism for now - this really needs a proper allocator.
3473 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
3474 == calculate_tls_end(tls_last_offset, tls_last_size)) {
3475 tls_last_offset -= obj->tlssize;
3482 _rtld_allocate_tls(void)
3484 struct tls_tcb *new_tcb;
3485 RtldLockState lockstate;
3487 wlock_acquire(rtld_bind_lock, &lockstate);
3488 new_tcb = allocate_tls(obj_list);
3489 lock_release(rtld_bind_lock, &lockstate);
3494 _rtld_free_tls(struct tls_tcb *tcb)
3496 RtldLockState lockstate;
3498 wlock_acquire(rtld_bind_lock, &lockstate);
3500 lock_release(rtld_bind_lock, &lockstate);
3504 object_add_name(Obj_Entry *obj, const char *name)
3510 entry = malloc(sizeof(Name_Entry) + len);
3512 if (entry != NULL) {
3513 strcpy(entry->name, name);
3514 STAILQ_INSERT_TAIL(&obj->names, entry, link);
3519 object_match_name(const Obj_Entry *obj, const char *name)
3523 STAILQ_FOREACH(entry, &obj->names, link) {
3524 if (strcmp(name, entry->name) == 0)
3531 locate_dependency(const Obj_Entry *obj, const char *name)
3533 const Objlist_Entry *entry;
3534 const Needed_Entry *needed;
3536 STAILQ_FOREACH(entry, &list_main, link) {
3537 if (object_match_name(entry->obj, name))
3541 for (needed = obj->needed; needed != NULL; needed = needed->next) {
3542 if (strcmp(obj->strtab + needed->name, name) == 0 ||
3543 (needed->obj != NULL && object_match_name(needed->obj, name))) {
3545 * If there is DT_NEEDED for the name we are looking for,
3546 * we are all set. Note that object might not be found if
3547 * dependency was not loaded yet, so the function can
3548 * return NULL here. This is expected and handled
3549 * properly by the caller.
3551 return (needed->obj);
3554 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
3560 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
3561 const Elf_Vernaux *vna)
3563 const Elf_Verdef *vd;
3564 const char *vername;
3566 vername = refobj->strtab + vna->vna_name;
3567 vd = depobj->verdef;
3569 _rtld_error("%s: version %s required by %s not defined",
3570 depobj->path, vername, refobj->path);
3574 if (vd->vd_version != VER_DEF_CURRENT) {
3575 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3576 depobj->path, vd->vd_version);
3579 if (vna->vna_hash == vd->vd_hash) {
3580 const Elf_Verdaux *aux = (const Elf_Verdaux *)
3581 ((char *)vd + vd->vd_aux);
3582 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
3585 if (vd->vd_next == 0)
3587 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3589 if (vna->vna_flags & VER_FLG_WEAK)
3591 _rtld_error("%s: version %s required by %s not found",
3592 depobj->path, vername, refobj->path);
3597 rtld_verify_object_versions(Obj_Entry *obj)
3599 const Elf_Verneed *vn;
3600 const Elf_Verdef *vd;
3601 const Elf_Verdaux *vda;
3602 const Elf_Vernaux *vna;
3603 const Obj_Entry *depobj;
3604 int maxvernum, vernum;
3608 * Walk over defined and required version records and figure out
3609 * max index used by any of them. Do very basic sanity checking
3613 while (vn != NULL) {
3614 if (vn->vn_version != VER_NEED_CURRENT) {
3615 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
3616 obj->path, vn->vn_version);
3619 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3621 vernum = VER_NEED_IDX(vna->vna_other);
3622 if (vernum > maxvernum)
3624 if (vna->vna_next == 0)
3626 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3628 if (vn->vn_next == 0)
3630 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3634 while (vd != NULL) {
3635 if (vd->vd_version != VER_DEF_CURRENT) {
3636 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3637 obj->path, vd->vd_version);
3640 vernum = VER_DEF_IDX(vd->vd_ndx);
3641 if (vernum > maxvernum)
3643 if (vd->vd_next == 0)
3645 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3652 * Store version information in array indexable by version index.
3653 * Verify that object version requirements are satisfied along the
3656 obj->vernum = maxvernum + 1;
3657 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry));
3660 while (vd != NULL) {
3661 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
3662 vernum = VER_DEF_IDX(vd->vd_ndx);
3663 assert(vernum <= maxvernum);
3664 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
3665 obj->vertab[vernum].hash = vd->vd_hash;
3666 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
3667 obj->vertab[vernum].file = NULL;
3668 obj->vertab[vernum].flags = 0;
3670 if (vd->vd_next == 0)
3672 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3676 while (vn != NULL) {
3677 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
3680 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3682 if (check_object_provided_version(obj, depobj, vna))
3684 vernum = VER_NEED_IDX(vna->vna_other);
3685 assert(vernum <= maxvernum);
3686 obj->vertab[vernum].hash = vna->vna_hash;
3687 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
3688 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
3689 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
3690 VER_INFO_HIDDEN : 0;
3691 if (vna->vna_next == 0)
3693 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3695 if (vn->vn_next == 0)
3697 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3703 rtld_verify_versions(const Objlist *objlist)
3705 Objlist_Entry *entry;
3709 STAILQ_FOREACH(entry, objlist, link) {
3711 * Skip dummy objects or objects that have their version requirements
3714 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
3716 if (rtld_verify_object_versions(entry->obj) == -1) {
3718 if (ld_tracing == NULL)
3722 if (rc == 0 || ld_tracing != NULL)
3723 rc = rtld_verify_object_versions(&obj_rtld);
3728 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
3733 vernum = VER_NDX(obj->versyms[symnum]);
3734 if (vernum >= obj->vernum) {
3735 _rtld_error("%s: symbol %s has wrong verneed value %d",
3736 obj->path, obj->strtab + symnum, vernum);
3737 } else if (obj->vertab[vernum].hash != 0) {
3738 return &obj->vertab[vernum];
3745 * No unresolved symbols for rtld.
3748 __pthread_cxa_finalize(struct dl_phdr_info *a)