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.
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>
44 #include <sys/sysctl.h>
46 #include <sys/utsname.h>
47 #include <sys/ktrace.h>
63 #include "rtld_printf.h"
67 #define PATH_RTLD "/libexec/ld-elf.so.1"
69 #define PATH_RTLD "/libexec/ld-elf32.so.1"
73 typedef void (*func_ptr_type)();
74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
77 * Function declarations.
79 static const char *basename(const char *);
80 static void die(void) __dead2;
81 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
83 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *);
84 static void digest_dynamic(Obj_Entry *, int);
85 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
86 static Obj_Entry *dlcheck(void *);
87 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
88 int lo_flags, int mode, RtldLockState *lockstate);
89 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
90 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
91 static bool donelist_check(DoneList *, const Obj_Entry *);
92 static void errmsg_restore(char *);
93 static char *errmsg_save(void);
94 static void *fill_search_info(const char *, size_t, void *);
95 static char *find_library(const char *, const Obj_Entry *);
96 static const char *gethints(void);
97 static void init_dag(Obj_Entry *);
98 static void init_rtld(caddr_t, Elf_Auxinfo **);
99 static void initlist_add_neededs(Needed_Entry *, Objlist *);
100 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
101 static void linkmap_add(Obj_Entry *);
102 static void linkmap_delete(Obj_Entry *);
103 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
104 static void unload_filtees(Obj_Entry *);
105 static int load_needed_objects(Obj_Entry *, int);
106 static int load_preload_objects(void);
107 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
108 static void map_stacks_exec(RtldLockState *);
109 static Obj_Entry *obj_from_addr(const void *);
110 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
111 static void objlist_call_init(Objlist *, RtldLockState *);
112 static void objlist_clear(Objlist *);
113 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
114 static void objlist_init(Objlist *);
115 static void objlist_push_head(Objlist *, Obj_Entry *);
116 static void objlist_push_tail(Objlist *, Obj_Entry *);
117 static void objlist_remove(Objlist *, Obj_Entry *);
118 static void *path_enumerate(const char *, path_enum_proc, void *);
119 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
121 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
122 int flags, RtldLockState *lockstate);
123 static int rtld_dirname(const char *, char *);
124 static int rtld_dirname_abs(const char *, char *);
125 static void *rtld_dlopen(const char *name, int fd, int mode);
126 static void rtld_exit(void);
127 static char *search_library_path(const char *, const char *);
128 static const void **get_program_var_addr(const char *, RtldLockState *);
129 static void set_program_var(const char *, const void *);
130 static int symlook_default(SymLook *, const Obj_Entry *refobj);
131 static int symlook_global(SymLook *, DoneList *);
132 static void symlook_init_from_req(SymLook *, const SymLook *);
133 static int symlook_list(SymLook *, const Objlist *, DoneList *);
134 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
135 static int symlook_obj1(SymLook *, const Obj_Entry *);
136 static void trace_loaded_objects(Obj_Entry *);
137 static void unlink_object(Obj_Entry *);
138 static void unload_object(Obj_Entry *);
139 static void unref_dag(Obj_Entry *);
140 static void ref_dag(Obj_Entry *);
141 static int origin_subst_one(char **, const char *, const char *,
142 const char *, char *);
143 static char *origin_subst(const char *, const char *);
144 static void preinit_main(void);
145 static int rtld_verify_versions(const Objlist *);
146 static int rtld_verify_object_versions(Obj_Entry *);
147 static void object_add_name(Obj_Entry *, const char *);
148 static int object_match_name(const Obj_Entry *, const char *);
149 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
150 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
151 struct dl_phdr_info *phdr_info);
153 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
158 static char *error_message; /* Message for dlerror(), or NULL */
159 struct r_debug r_debug; /* for GDB; */
160 static bool libmap_disable; /* Disable libmap */
161 static bool ld_loadfltr; /* Immediate filters processing */
162 static char *libmap_override; /* Maps to use in addition to libmap.conf */
163 static bool trust; /* False for setuid and setgid programs */
164 static bool dangerous_ld_env; /* True if environment variables have been
165 used to affect the libraries loaded */
166 static char *ld_bind_now; /* Environment variable for immediate binding */
167 static char *ld_debug; /* Environment variable for debugging */
168 static char *ld_library_path; /* Environment variable for search path */
169 static char *ld_preload; /* Environment variable for libraries to
171 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
172 static char *ld_tracing; /* Called from ldd to print libs */
173 static char *ld_utrace; /* Use utrace() to log events. */
174 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
175 static Obj_Entry **obj_tail; /* Link field of last object in list */
176 static Obj_Entry *obj_main; /* The main program shared object */
177 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
178 static unsigned int obj_count; /* Number of objects in obj_list */
179 static unsigned int obj_loads; /* Number of objects in obj_list */
181 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
182 STAILQ_HEAD_INITIALIZER(list_global);
183 static Objlist list_main = /* Objects loaded at program startup */
184 STAILQ_HEAD_INITIALIZER(list_main);
185 static Objlist list_fini = /* Objects needing fini() calls */
186 STAILQ_HEAD_INITIALIZER(list_fini);
188 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
190 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
192 extern Elf_Dyn _DYNAMIC;
193 #pragma weak _DYNAMIC
194 #ifndef RTLD_IS_DYNAMIC
195 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
198 int osreldate, pagesize;
200 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
202 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
203 static int max_stack_flags;
206 * Global declarations normally provided by crt1. The dynamic linker is
207 * not built with crt1, so we have to provide them ourselves.
213 * Used to pass argc, argv to init functions.
219 * Globals to control TLS allocation.
221 size_t tls_last_offset; /* Static TLS offset of last module */
222 size_t tls_last_size; /* Static TLS size of last module */
223 size_t tls_static_space; /* Static TLS space allocated */
224 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
225 int tls_max_index = 1; /* Largest module index allocated */
228 * Fill in a DoneList with an allocation large enough to hold all of
229 * the currently-loaded objects. Keep this as a macro since it calls
230 * alloca and we want that to occur within the scope of the caller.
232 #define donelist_init(dlp) \
233 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
234 assert((dlp)->objs != NULL), \
235 (dlp)->num_alloc = obj_count, \
238 #define UTRACE_DLOPEN_START 1
239 #define UTRACE_DLOPEN_STOP 2
240 #define UTRACE_DLCLOSE_START 3
241 #define UTRACE_DLCLOSE_STOP 4
242 #define UTRACE_LOAD_OBJECT 5
243 #define UTRACE_UNLOAD_OBJECT 6
244 #define UTRACE_ADD_RUNDEP 7
245 #define UTRACE_PRELOAD_FINISHED 8
246 #define UTRACE_INIT_CALL 9
247 #define UTRACE_FINI_CALL 10
250 char sig[4]; /* 'RTLD' */
253 void *mapbase; /* Used for 'parent' and 'init/fini' */
255 int refcnt; /* Used for 'mode' */
256 char name[MAXPATHLEN];
259 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
260 if (ld_utrace != NULL) \
261 ld_utrace_log(e, h, mb, ms, r, n); \
265 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
266 int refcnt, const char *name)
268 struct utrace_rtld ut;
276 ut.mapbase = mapbase;
277 ut.mapsize = mapsize;
279 bzero(ut.name, sizeof(ut.name));
281 strlcpy(ut.name, name, sizeof(ut.name));
282 utrace(&ut, sizeof(ut));
286 * Main entry point for dynamic linking. The first argument is the
287 * stack pointer. The stack is expected to be laid out as described
288 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
289 * Specifically, the stack pointer points to a word containing
290 * ARGC. Following that in the stack is a null-terminated sequence
291 * of pointers to argument strings. Then comes a null-terminated
292 * sequence of pointers to environment strings. Finally, there is a
293 * sequence of "auxiliary vector" entries.
295 * The second argument points to a place to store the dynamic linker's
296 * exit procedure pointer and the third to a place to store the main
299 * The return value is the main program's entry point.
302 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
304 Elf_Auxinfo *aux_info[AT_COUNT];
312 Objlist_Entry *entry;
314 Obj_Entry **preload_tail;
316 RtldLockState lockstate;
321 * On entry, the dynamic linker itself has not been relocated yet.
322 * Be very careful not to reference any global data until after
323 * init_rtld has returned. It is OK to reference file-scope statics
324 * and string constants, and to call static and global functions.
327 /* Find the auxiliary vector on the stack. */
330 sp += argc + 1; /* Skip over arguments and NULL terminator */
332 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
334 aux = (Elf_Auxinfo *) sp;
336 /* Digest the auxiliary vector. */
337 for (i = 0; i < AT_COUNT; i++)
339 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
340 if (auxp->a_type < AT_COUNT)
341 aux_info[auxp->a_type] = auxp;
344 /* Initialize and relocate ourselves. */
345 assert(aux_info[AT_BASE] != NULL);
346 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
348 __progname = obj_rtld.path;
349 argv0 = argv[0] != NULL ? argv[0] : "(null)";
354 if (aux_info[AT_CANARY] != NULL &&
355 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
356 i = aux_info[AT_CANARYLEN]->a_un.a_val;
357 if (i > sizeof(__stack_chk_guard))
358 i = sizeof(__stack_chk_guard);
359 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
364 len = sizeof(__stack_chk_guard);
365 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
366 len != sizeof(__stack_chk_guard)) {
367 /* If sysctl was unsuccessful, use the "terminator canary". */
368 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
369 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
370 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
371 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
375 trust = !issetugid();
377 ld_bind_now = getenv(LD_ "BIND_NOW");
379 * If the process is tainted, then we un-set the dangerous environment
380 * variables. The process will be marked as tainted until setuid(2)
381 * is called. If any child process calls setuid(2) we do not want any
382 * future processes to honor the potentially un-safe variables.
385 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
386 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
387 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
388 unsetenv(LD_ "LOADFLTR")) {
389 _rtld_error("environment corrupt; aborting");
393 ld_debug = getenv(LD_ "DEBUG");
394 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
395 libmap_override = getenv(LD_ "LIBMAP");
396 ld_library_path = getenv(LD_ "LIBRARY_PATH");
397 ld_preload = getenv(LD_ "PRELOAD");
398 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
399 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
400 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
401 (ld_library_path != NULL) || (ld_preload != NULL) ||
402 (ld_elf_hints_path != NULL) || ld_loadfltr;
403 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
404 ld_utrace = getenv(LD_ "UTRACE");
406 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
407 ld_elf_hints_path = _PATH_ELF_HINTS;
409 if (ld_debug != NULL && *ld_debug != '\0')
411 dbg("%s is initialized, base address = %p", __progname,
412 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
413 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
414 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
416 dbg("initializing thread locks");
420 * Load the main program, or process its program header if it is
423 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
424 int fd = aux_info[AT_EXECFD]->a_un.a_val;
425 dbg("loading main program");
426 obj_main = map_object(fd, argv0, NULL);
428 if (obj_main == NULL)
430 max_stack_flags = obj->stack_flags;
431 } else { /* Main program already loaded. */
432 const Elf_Phdr *phdr;
436 dbg("processing main program's program header");
437 assert(aux_info[AT_PHDR] != NULL);
438 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
439 assert(aux_info[AT_PHNUM] != NULL);
440 phnum = aux_info[AT_PHNUM]->a_un.a_val;
441 assert(aux_info[AT_PHENT] != NULL);
442 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
443 assert(aux_info[AT_ENTRY] != NULL);
444 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
445 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
449 if (aux_info[AT_EXECPATH] != 0) {
451 char buf[MAXPATHLEN];
453 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
454 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
455 if (kexecpath[0] == '/')
456 obj_main->path = kexecpath;
457 else if (getcwd(buf, sizeof(buf)) == NULL ||
458 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
459 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
460 obj_main->path = xstrdup(argv0);
462 obj_main->path = xstrdup(buf);
464 dbg("No AT_EXECPATH");
465 obj_main->path = xstrdup(argv0);
467 dbg("obj_main path %s", obj_main->path);
468 obj_main->mainprog = true;
470 if (aux_info[AT_STACKPROT] != NULL &&
471 aux_info[AT_STACKPROT]->a_un.a_val != 0)
472 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
475 * Get the actual dynamic linker pathname from the executable if
476 * possible. (It should always be possible.) That ensures that
477 * gdb will find the right dynamic linker even if a non-standard
480 if (obj_main->interp != NULL &&
481 strcmp(obj_main->interp, obj_rtld.path) != 0) {
483 obj_rtld.path = xstrdup(obj_main->interp);
484 __progname = obj_rtld.path;
487 digest_dynamic(obj_main, 0);
489 linkmap_add(obj_main);
490 linkmap_add(&obj_rtld);
492 /* Link the main program into the list of objects. */
493 *obj_tail = obj_main;
494 obj_tail = &obj_main->next;
498 /* Initialize a fake symbol for resolving undefined weak references. */
499 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
500 sym_zero.st_shndx = SHN_UNDEF;
501 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
504 libmap_disable = (bool)lm_init(libmap_override);
506 dbg("loading LD_PRELOAD libraries");
507 if (load_preload_objects() == -1)
509 preload_tail = obj_tail;
511 dbg("loading needed objects");
512 if (load_needed_objects(obj_main, 0) == -1)
515 /* Make a list of all objects loaded at startup. */
516 for (obj = obj_list; obj != NULL; obj = obj->next) {
517 objlist_push_tail(&list_main, obj);
521 dbg("checking for required versions");
522 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
525 if (ld_tracing) { /* We're done */
526 trace_loaded_objects(obj_main);
530 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
531 dump_relocations(obj_main);
536 * Processing tls relocations requires having the tls offsets
537 * initialized. Prepare offsets before starting initial
538 * relocation processing.
540 dbg("initializing initial thread local storage offsets");
541 STAILQ_FOREACH(entry, &list_main, link) {
543 * Allocate all the initial objects out of the static TLS
544 * block even if they didn't ask for it.
546 allocate_tls_offset(entry->obj);
549 if (relocate_objects(obj_main,
550 ld_bind_now != NULL && *ld_bind_now != '\0',
551 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
554 dbg("doing copy relocations");
555 if (do_copy_relocations(obj_main) == -1)
558 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
559 dump_relocations(obj_main);
564 * Setup TLS for main thread. This must be done after the
565 * relocations are processed, since tls initialization section
566 * might be the subject for relocations.
568 dbg("initializing initial thread local storage");
569 allocate_initial_tls(obj_list);
571 dbg("initializing key program variables");
572 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
573 set_program_var("environ", env);
574 set_program_var("__elf_aux_vector", aux);
576 /* Make a list of init functions to call. */
577 objlist_init(&initlist);
578 initlist_add_objects(obj_list, preload_tail, &initlist);
580 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
582 map_stacks_exec(NULL);
584 dbg("resolving ifuncs");
585 if (resolve_objects_ifunc(obj_main,
586 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
590 if (!obj_main->crt_no_init) {
592 * Make sure we don't call the main program's init and fini
593 * functions for binaries linked with old crt1 which calls
596 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
597 obj_main->preinit_array = obj_main->init_array =
598 obj_main->fini_array = (Elf_Addr)NULL;
601 wlock_acquire(rtld_bind_lock, &lockstate);
602 if (obj_main->crt_no_init)
604 objlist_call_init(&initlist, &lockstate);
605 objlist_clear(&initlist);
606 dbg("loading filtees");
607 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
608 if (ld_loadfltr || obj->z_loadfltr)
609 load_filtees(obj, 0, &lockstate);
611 lock_release(rtld_bind_lock, &lockstate);
613 dbg("transferring control to program entry point = %p", obj_main->entry);
615 /* Return the exit procedure and the program entry point. */
616 *exit_proc = rtld_exit;
618 return (func_ptr_type) obj_main->entry;
622 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
627 ptr = (void *)make_function_pointer(def, obj);
628 target = ((Elf_Addr (*)(void))ptr)();
629 return ((void *)target);
633 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
637 const Obj_Entry *defobj;
640 RtldLockState lockstate;
642 rlock_acquire(rtld_bind_lock, &lockstate);
643 if (sigsetjmp(lockstate.env, 0) != 0)
644 lock_upgrade(rtld_bind_lock, &lockstate);
646 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
648 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
650 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
651 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
655 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
656 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
658 target = (Elf_Addr)(defobj->relocbase + def->st_value);
660 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
661 defobj->strtab + def->st_name, basename(obj->path),
662 (void *)target, basename(defobj->path));
665 * Write the new contents for the jmpslot. Note that depending on
666 * architecture, the value which we need to return back to the
667 * lazy binding trampoline may or may not be the target
668 * address. The value returned from reloc_jmpslot() is the value
669 * that the trampoline needs.
671 target = reloc_jmpslot(where, target, defobj, obj, rel);
672 lock_release(rtld_bind_lock, &lockstate);
677 * Error reporting function. Use it like printf. If formats the message
678 * into a buffer, and sets things up so that the next call to dlerror()
679 * will return the message.
682 _rtld_error(const char *fmt, ...)
684 static char buf[512];
688 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
694 * Return a dynamically-allocated copy of the current error message, if any.
699 return error_message == NULL ? NULL : xstrdup(error_message);
703 * Restore the current error message from a copy which was previously saved
704 * by errmsg_save(). The copy is freed.
707 errmsg_restore(char *saved_msg)
709 if (saved_msg == NULL)
710 error_message = NULL;
712 _rtld_error("%s", saved_msg);
718 basename(const char *name)
720 const char *p = strrchr(name, '/');
721 return p != NULL ? p + 1 : name;
724 static struct utsname uts;
727 origin_subst_one(char **res, const char *real, const char *kw, const char *subst,
737 subst_len = kw_len = 0;
741 if (subst_len == 0) {
742 subst_len = strlen(subst);
746 *res = xmalloc(PATH_MAX);
749 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) {
750 _rtld_error("Substitution of %s in %s cannot be performed",
752 if (may_free != NULL)
757 memcpy(res1, p, p1 - p);
759 memcpy(res1, subst, subst_len);
764 if (may_free != NULL)
767 *res = xstrdup(real);
771 if (may_free != NULL)
773 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) {
783 origin_subst(const char *real, const char *origin_path)
785 char *res1, *res2, *res3, *res4;
787 if (uts.sysname[0] == '\0') {
788 if (uname(&uts) != 0) {
789 _rtld_error("utsname failed: %d", errno);
793 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) ||
794 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) ||
795 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) ||
796 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3))
804 const char *msg = dlerror();
808 rtld_fdputstr(STDERR_FILENO, msg);
809 rtld_fdputchar(STDERR_FILENO, '\n');
814 * Process a shared object's DYNAMIC section, and save the important
815 * information in its Obj_Entry structure.
818 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
819 const Elf_Dyn **dyn_soname)
822 Needed_Entry **needed_tail = &obj->needed;
823 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
824 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
825 int plttype = DT_REL;
830 obj->bind_now = false;
831 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
832 switch (dynp->d_tag) {
835 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
839 obj->relsize = dynp->d_un.d_val;
843 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
847 obj->pltrel = (const Elf_Rel *)
848 (obj->relocbase + dynp->d_un.d_ptr);
852 obj->pltrelsize = dynp->d_un.d_val;
856 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
860 obj->relasize = dynp->d_un.d_val;
864 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
868 plttype = dynp->d_un.d_val;
869 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
873 obj->symtab = (const Elf_Sym *)
874 (obj->relocbase + dynp->d_un.d_ptr);
878 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
882 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
886 obj->strsize = dynp->d_un.d_val;
890 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
895 obj->verneednum = dynp->d_un.d_val;
899 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
904 obj->verdefnum = dynp->d_un.d_val;
908 obj->versyms = (const Elf_Versym *)(obj->relocbase +
914 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
915 (obj->relocbase + dynp->d_un.d_ptr);
916 obj->nbuckets = hashtab[0];
917 obj->nchains = hashtab[1];
918 obj->buckets = hashtab + 2;
919 obj->chains = obj->buckets + obj->nbuckets;
925 Needed_Entry *nep = NEW(Needed_Entry);
926 nep->name = dynp->d_un.d_val;
931 needed_tail = &nep->next;
937 Needed_Entry *nep = NEW(Needed_Entry);
938 nep->name = dynp->d_un.d_val;
942 *needed_filtees_tail = nep;
943 needed_filtees_tail = &nep->next;
949 Needed_Entry *nep = NEW(Needed_Entry);
950 nep->name = dynp->d_un.d_val;
954 *needed_aux_filtees_tail = nep;
955 needed_aux_filtees_tail = &nep->next;
960 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
968 obj->symbolic = true;
972 case DT_RUNPATH: /* XXX: process separately */
974 * We have to wait until later to process this, because we
975 * might not have gotten the address of the string table yet.
985 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
988 case DT_PREINIT_ARRAY:
989 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
992 case DT_PREINIT_ARRAYSZ:
993 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
997 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1000 case DT_INIT_ARRAYSZ:
1001 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1005 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1009 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1012 case DT_FINI_ARRAYSZ:
1013 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1017 * Don't process DT_DEBUG on MIPS as the dynamic section
1018 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1023 /* XXX - not implemented yet */
1025 dbg("Filling in DT_DEBUG entry");
1026 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1031 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1032 obj->z_origin = true;
1033 if (dynp->d_un.d_val & DF_SYMBOLIC)
1034 obj->symbolic = true;
1035 if (dynp->d_un.d_val & DF_TEXTREL)
1036 obj->textrel = true;
1037 if (dynp->d_un.d_val & DF_BIND_NOW)
1038 obj->bind_now = true;
1039 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1043 case DT_MIPS_LOCAL_GOTNO:
1044 obj->local_gotno = dynp->d_un.d_val;
1047 case DT_MIPS_SYMTABNO:
1048 obj->symtabno = dynp->d_un.d_val;
1051 case DT_MIPS_GOTSYM:
1052 obj->gotsym = dynp->d_un.d_val;
1055 case DT_MIPS_RLD_MAP:
1058 dbg("Filling in DT_DEBUG entry");
1059 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1065 if (dynp->d_un.d_val & DF_1_NOOPEN)
1066 obj->z_noopen = true;
1067 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1068 obj->z_origin = true;
1069 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1071 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1072 obj->bind_now = true;
1073 if (dynp->d_un.d_val & DF_1_NODELETE)
1074 obj->z_nodelete = true;
1075 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1076 obj->z_loadfltr = true;
1081 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1088 obj->traced = false;
1090 if (plttype == DT_RELA) {
1091 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1093 obj->pltrelasize = obj->pltrelsize;
1094 obj->pltrelsize = 0;
1099 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1100 const Elf_Dyn *dyn_soname)
1103 if (obj->z_origin && obj->origin_path == NULL) {
1104 obj->origin_path = xmalloc(PATH_MAX);
1105 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1109 if (dyn_rpath != NULL) {
1110 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1112 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1115 if (dyn_soname != NULL)
1116 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1120 digest_dynamic(Obj_Entry *obj, int early)
1122 const Elf_Dyn *dyn_rpath;
1123 const Elf_Dyn *dyn_soname;
1125 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname);
1126 digest_dynamic2(obj, dyn_rpath, dyn_soname);
1130 * Process a shared object's program header. This is used only for the
1131 * main program, when the kernel has already loaded the main program
1132 * into memory before calling the dynamic linker. It creates and
1133 * returns an Obj_Entry structure.
1136 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1139 const Elf_Phdr *phlimit = phdr + phnum;
1141 Elf_Addr note_start, note_end;
1145 for (ph = phdr; ph < phlimit; ph++) {
1146 if (ph->p_type != PT_PHDR)
1150 obj->phsize = ph->p_memsz;
1151 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1155 obj->stack_flags = PF_X | PF_R | PF_W;
1157 for (ph = phdr; ph < phlimit; ph++) {
1158 switch (ph->p_type) {
1161 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1165 if (nsegs == 0) { /* First load segment */
1166 obj->vaddrbase = trunc_page(ph->p_vaddr);
1167 obj->mapbase = obj->vaddrbase + obj->relocbase;
1168 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1170 } else { /* Last load segment */
1171 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1178 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1183 obj->tlssize = ph->p_memsz;
1184 obj->tlsalign = ph->p_align;
1185 obj->tlsinitsize = ph->p_filesz;
1186 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1190 obj->stack_flags = ph->p_flags;
1194 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1195 obj->relro_size = round_page(ph->p_memsz);
1199 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1200 note_end = note_start + ph->p_filesz;
1201 digest_notes(obj, note_start, note_end);
1206 _rtld_error("%s: too few PT_LOAD segments", path);
1215 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1217 const Elf_Note *note;
1218 const char *note_name;
1221 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1222 note = (const Elf_Note *)((const char *)(note + 1) +
1223 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1224 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1225 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1226 note->n_descsz != sizeof(int32_t))
1228 if (note->n_type != ABI_NOTETYPE &&
1229 note->n_type != CRT_NOINIT_NOTETYPE)
1231 note_name = (const char *)(note + 1);
1232 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1233 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1235 switch (note->n_type) {
1237 /* FreeBSD osrel note */
1238 p = (uintptr_t)(note + 1);
1239 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1240 obj->osrel = *(const int32_t *)(p);
1241 dbg("note osrel %d", obj->osrel);
1243 case CRT_NOINIT_NOTETYPE:
1244 /* FreeBSD 'crt does not call init' note */
1245 obj->crt_no_init = true;
1246 dbg("note crt_no_init");
1253 dlcheck(void *handle)
1257 for (obj = obj_list; obj != NULL; obj = obj->next)
1258 if (obj == (Obj_Entry *) handle)
1261 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1262 _rtld_error("Invalid shared object handle %p", handle);
1269 * If the given object is already in the donelist, return true. Otherwise
1270 * add the object to the list and return false.
1273 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1277 for (i = 0; i < dlp->num_used; i++)
1278 if (dlp->objs[i] == obj)
1281 * Our donelist allocation should always be sufficient. But if
1282 * our threads locking isn't working properly, more shared objects
1283 * could have been loaded since we allocated the list. That should
1284 * never happen, but we'll handle it properly just in case it does.
1286 if (dlp->num_used < dlp->num_alloc)
1287 dlp->objs[dlp->num_used++] = obj;
1292 * Hash function for symbol table lookup. Don't even think about changing
1293 * this. It is specified by the System V ABI.
1296 elf_hash(const char *name)
1298 const unsigned char *p = (const unsigned char *) name;
1299 unsigned long h = 0;
1302 while (*p != '\0') {
1303 h = (h << 4) + *p++;
1304 if ((g = h & 0xf0000000) != 0)
1312 * Find the library with the given name, and return its full pathname.
1313 * The returned string is dynamically allocated. Generates an error
1314 * message and returns NULL if the library cannot be found.
1316 * If the second argument is non-NULL, then it refers to an already-
1317 * loaded shared object, whose library search path will be searched.
1319 * The search order is:
1321 * rpath in the referencing file
1326 find_library(const char *xname, const Obj_Entry *refobj)
1331 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1332 if (xname[0] != '/' && !trust) {
1333 _rtld_error("Absolute pathname required for shared object \"%s\"",
1337 if (refobj != NULL && refobj->z_origin)
1338 return origin_subst(xname, refobj->origin_path);
1340 return xstrdup(xname);
1343 if (libmap_disable || (refobj == NULL) ||
1344 (name = lm_find(refobj->path, xname)) == NULL)
1345 name = (char *)xname;
1347 dbg(" Searching for \"%s\"", name);
1349 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1351 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1352 (pathname = search_library_path(name, gethints())) != NULL ||
1353 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1356 if(refobj != NULL && refobj->path != NULL) {
1357 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1358 name, basename(refobj->path));
1360 _rtld_error("Shared object \"%s\" not found", name);
1366 * Given a symbol number in a referencing object, find the corresponding
1367 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1368 * no definition was found. Returns a pointer to the Obj_Entry of the
1369 * defining object via the reference parameter DEFOBJ_OUT.
1372 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1373 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1374 RtldLockState *lockstate)
1378 const Obj_Entry *defobj;
1384 * If we have already found this symbol, get the information from
1387 if (symnum >= refobj->nchains)
1388 return NULL; /* Bad object */
1389 if (cache != NULL && cache[symnum].sym != NULL) {
1390 *defobj_out = cache[symnum].obj;
1391 return cache[symnum].sym;
1394 ref = refobj->symtab + symnum;
1395 name = refobj->strtab + ref->st_name;
1400 * We don't have to do a full scale lookup if the symbol is local.
1401 * We know it will bind to the instance in this load module; to
1402 * which we already have a pointer (ie ref). By not doing a lookup,
1403 * we not only improve performance, but it also avoids unresolvable
1404 * symbols when local symbols are not in the hash table. This has
1405 * been seen with the ia64 toolchain.
1407 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1408 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1409 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1412 symlook_init(&req, name);
1414 req.ventry = fetch_ventry(refobj, symnum);
1415 req.lockstate = lockstate;
1416 res = symlook_default(&req, refobj);
1419 defobj = req.defobj_out;
1427 * If we found no definition and the reference is weak, treat the
1428 * symbol as having the value zero.
1430 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1436 *defobj_out = defobj;
1437 /* Record the information in the cache to avoid subsequent lookups. */
1438 if (cache != NULL) {
1439 cache[symnum].sym = def;
1440 cache[symnum].obj = defobj;
1443 if (refobj != &obj_rtld)
1444 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1450 * Return the search path from the ldconfig hints file, reading it if
1451 * necessary. Returns NULL if there are problems with the hints file,
1452 * or if the search path there is empty.
1459 if (hints == NULL) {
1461 struct elfhints_hdr hdr;
1464 /* Keep from trying again in case the hints file is bad. */
1467 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1469 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1470 hdr.magic != ELFHINTS_MAGIC ||
1475 p = xmalloc(hdr.dirlistlen + 1);
1476 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1477 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1485 return hints[0] != '\0' ? hints : NULL;
1489 init_dag(Obj_Entry *root)
1491 const Needed_Entry *needed;
1492 const Objlist_Entry *elm;
1495 if (root->dag_inited)
1497 donelist_init(&donelist);
1499 /* Root object belongs to own DAG. */
1500 objlist_push_tail(&root->dldags, root);
1501 objlist_push_tail(&root->dagmembers, root);
1502 donelist_check(&donelist, root);
1505 * Add dependencies of root object to DAG in breadth order
1506 * by exploiting the fact that each new object get added
1507 * to the tail of the dagmembers list.
1509 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1510 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1511 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1513 objlist_push_tail(&needed->obj->dldags, root);
1514 objlist_push_tail(&root->dagmembers, needed->obj);
1517 root->dag_inited = true;
1521 * Initialize the dynamic linker. The argument is the address at which
1522 * the dynamic linker has been mapped into memory. The primary task of
1523 * this function is to relocate the dynamic linker.
1526 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1528 Obj_Entry objtmp; /* Temporary rtld object */
1529 const Elf_Dyn *dyn_rpath;
1530 const Elf_Dyn *dyn_soname;
1533 * Conjure up an Obj_Entry structure for the dynamic linker.
1535 * The "path" member can't be initialized yet because string constants
1536 * cannot yet be accessed. Below we will set it correctly.
1538 memset(&objtmp, 0, sizeof(objtmp));
1541 objtmp.mapbase = mapbase;
1543 objtmp.relocbase = mapbase;
1545 if (RTLD_IS_DYNAMIC()) {
1546 objtmp.dynamic = rtld_dynamic(&objtmp);
1547 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname);
1548 assert(objtmp.needed == NULL);
1549 #if !defined(__mips__)
1550 /* MIPS has a bogus DT_TEXTREL. */
1551 assert(!objtmp.textrel);
1555 * Temporarily put the dynamic linker entry into the object list, so
1556 * that symbols can be found.
1559 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1562 /* Initialize the object list. */
1563 obj_tail = &obj_list;
1565 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1566 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1568 if (aux_info[AT_PAGESZ] != NULL)
1569 pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
1570 if (aux_info[AT_OSRELDATE] != NULL)
1571 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1573 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname);
1575 /* Replace the path with a dynamically allocated copy. */
1576 obj_rtld.path = xstrdup(PATH_RTLD);
1578 r_debug.r_brk = r_debug_state;
1579 r_debug.r_state = RT_CONSISTENT;
1583 * Add the init functions from a needed object list (and its recursive
1584 * needed objects) to "list". This is not used directly; it is a helper
1585 * function for initlist_add_objects(). The write lock must be held
1586 * when this function is called.
1589 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1591 /* Recursively process the successor needed objects. */
1592 if (needed->next != NULL)
1593 initlist_add_neededs(needed->next, list);
1595 /* Process the current needed object. */
1596 if (needed->obj != NULL)
1597 initlist_add_objects(needed->obj, &needed->obj->next, list);
1601 * Scan all of the DAGs rooted in the range of objects from "obj" to
1602 * "tail" and add their init functions to "list". This recurses over
1603 * the DAGs and ensure the proper init ordering such that each object's
1604 * needed libraries are initialized before the object itself. At the
1605 * same time, this function adds the objects to the global finalization
1606 * list "list_fini" in the opposite order. The write lock must be
1607 * held when this function is called.
1610 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1613 if (obj->init_scanned || obj->init_done)
1615 obj->init_scanned = true;
1617 /* Recursively process the successor objects. */
1618 if (&obj->next != tail)
1619 initlist_add_objects(obj->next, tail, list);
1621 /* Recursively process the needed objects. */
1622 if (obj->needed != NULL)
1623 initlist_add_neededs(obj->needed, list);
1624 if (obj->needed_filtees != NULL)
1625 initlist_add_neededs(obj->needed_filtees, list);
1626 if (obj->needed_aux_filtees != NULL)
1627 initlist_add_neededs(obj->needed_aux_filtees, list);
1629 /* Add the object to the init list. */
1630 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1631 obj->init_array != (Elf_Addr)NULL)
1632 objlist_push_tail(list, obj);
1634 /* Add the object to the global fini list in the reverse order. */
1635 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1636 && !obj->on_fini_list) {
1637 objlist_push_head(&list_fini, obj);
1638 obj->on_fini_list = true;
1643 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1647 free_needed_filtees(Needed_Entry *n)
1649 Needed_Entry *needed, *needed1;
1651 for (needed = n; needed != NULL; needed = needed->next) {
1652 if (needed->obj != NULL) {
1653 dlclose(needed->obj);
1657 for (needed = n; needed != NULL; needed = needed1) {
1658 needed1 = needed->next;
1664 unload_filtees(Obj_Entry *obj)
1667 free_needed_filtees(obj->needed_filtees);
1668 obj->needed_filtees = NULL;
1669 free_needed_filtees(obj->needed_aux_filtees);
1670 obj->needed_aux_filtees = NULL;
1671 obj->filtees_loaded = false;
1675 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
1676 RtldLockState *lockstate)
1679 for (; needed != NULL; needed = needed->next) {
1680 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1681 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1682 RTLD_LOCAL, lockstate);
1687 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1690 lock_restart_for_upgrade(lockstate);
1691 if (!obj->filtees_loaded) {
1692 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
1693 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
1694 obj->filtees_loaded = true;
1699 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1703 for (; needed != NULL; needed = needed->next) {
1704 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
1705 flags & ~RTLD_LO_NOLOAD);
1706 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1708 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
1709 dbg("obj %s nodelete", obj1->path);
1712 obj1->ref_nodel = true;
1719 * Given a shared object, traverse its list of needed objects, and load
1720 * each of them. Returns 0 on success. Generates an error message and
1721 * returns -1 on failure.
1724 load_needed_objects(Obj_Entry *first, int flags)
1728 for (obj = first; obj != NULL; obj = obj->next) {
1729 if (process_needed(obj, obj->needed, flags) == -1)
1736 load_preload_objects(void)
1738 char *p = ld_preload;
1739 static const char delim[] = " \t:;";
1744 p += strspn(p, delim);
1745 while (*p != '\0') {
1746 size_t len = strcspn(p, delim);
1751 if (load_object(p, -1, NULL, 0) == NULL)
1752 return -1; /* XXX - cleanup */
1755 p += strspn(p, delim);
1757 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
1762 printable_path(const char *path)
1765 return (path == NULL ? "<unknown>" : path);
1769 * Load a shared object into memory, if it is not already loaded. The
1770 * object may be specified by name or by user-supplied file descriptor
1771 * fd_u. In the later case, the fd_u descriptor is not closed, but its
1774 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1778 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
1786 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
1787 if (object_match_name(obj, name))
1791 path = find_library(name, refobj);
1798 * If we didn't find a match by pathname, or the name is not
1799 * supplied, open the file and check again by device and inode.
1800 * This avoids false mismatches caused by multiple links or ".."
1803 * To avoid a race, we open the file and use fstat() rather than
1808 if ((fd = open(path, O_RDONLY)) == -1) {
1809 _rtld_error("Cannot open \"%s\"", path);
1816 _rtld_error("Cannot dup fd");
1821 if (fstat(fd, &sb) == -1) {
1822 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
1827 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1828 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
1830 if (obj != NULL && name != NULL) {
1831 object_add_name(obj, name);
1836 if (flags & RTLD_LO_NOLOAD) {
1842 /* First use of this object, so we must map it in */
1843 obj = do_load_object(fd, name, path, &sb, flags);
1852 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
1859 * but first, make sure that environment variables haven't been
1860 * used to circumvent the noexec flag on a filesystem.
1862 if (dangerous_ld_env) {
1863 if (fstatfs(fd, &fs) != 0) {
1864 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
1867 if (fs.f_flags & MNT_NOEXEC) {
1868 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
1872 dbg("loading \"%s\"", printable_path(path));
1873 obj = map_object(fd, printable_path(path), sbp);
1878 * If DT_SONAME is present in the object, digest_dynamic2 already
1879 * added it to the object names.
1882 object_add_name(obj, name);
1884 digest_dynamic(obj, 0);
1885 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
1887 dbg("refusing to load non-loadable \"%s\"", obj->path);
1888 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
1889 munmap(obj->mapbase, obj->mapsize);
1895 obj_tail = &obj->next;
1898 linkmap_add(obj); /* for GDB & dlinfo() */
1899 max_stack_flags |= obj->stack_flags;
1901 dbg(" %p .. %p: %s", obj->mapbase,
1902 obj->mapbase + obj->mapsize - 1, obj->path);
1904 dbg(" WARNING: %s has impure text", obj->path);
1905 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
1912 obj_from_addr(const void *addr)
1916 for (obj = obj_list; obj != NULL; obj = obj->next) {
1917 if (addr < (void *) obj->mapbase)
1919 if (addr < (void *) (obj->mapbase + obj->mapsize))
1928 Elf_Addr *preinit_addr;
1931 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
1932 if (preinit_addr == NULL)
1935 for (index = 0; index < obj_main->preinit_array_num; index++) {
1936 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
1937 dbg("calling preinit function for %s at %p", obj_main->path,
1938 (void *)preinit_addr[index]);
1939 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
1940 0, 0, obj_main->path);
1941 call_init_pointer(obj_main, preinit_addr[index]);
1947 * Call the finalization functions for each of the objects in "list"
1948 * belonging to the DAG of "root" and referenced once. If NULL "root"
1949 * is specified, every finalization function will be called regardless
1950 * of the reference count and the list elements won't be freed. All of
1951 * the objects are expected to have non-NULL fini functions.
1954 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
1958 Elf_Addr *fini_addr;
1961 assert(root == NULL || root->refcount == 1);
1964 * Preserve the current error message since a fini function might
1965 * call into the dynamic linker and overwrite it.
1967 saved_msg = errmsg_save();
1969 STAILQ_FOREACH(elm, list, link) {
1970 if (root != NULL && (elm->obj->refcount != 1 ||
1971 objlist_find(&root->dagmembers, elm->obj) == NULL))
1973 /* Remove object from fini list to prevent recursive invocation. */
1974 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1976 * XXX: If a dlopen() call references an object while the
1977 * fini function is in progress, we might end up trying to
1978 * unload the referenced object in dlclose() or the object
1979 * won't be unloaded although its fini function has been
1982 lock_release(rtld_bind_lock, lockstate);
1985 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
1986 * When this happens, DT_FINI_ARRAY is processed first.
1988 fini_addr = (Elf_Addr *)elm->obj->fini_array;
1989 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
1990 for (index = elm->obj->fini_array_num - 1; index >= 0;
1992 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
1993 dbg("calling fini function for %s at %p",
1994 elm->obj->path, (void *)fini_addr[index]);
1995 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
1996 (void *)fini_addr[index], 0, 0, elm->obj->path);
1997 call_initfini_pointer(elm->obj, fini_addr[index]);
2001 if (elm->obj->fini != (Elf_Addr)NULL) {
2002 dbg("calling fini function for %s at %p", elm->obj->path,
2003 (void *)elm->obj->fini);
2004 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2005 0, 0, elm->obj->path);
2006 call_initfini_pointer(elm->obj, elm->obj->fini);
2008 wlock_acquire(rtld_bind_lock, lockstate);
2009 /* No need to free anything if process is going down. */
2013 * We must restart the list traversal after every fini call
2014 * because a dlclose() call from the fini function or from
2015 * another thread might have modified the reference counts.
2019 } while (elm != NULL);
2020 errmsg_restore(saved_msg);
2024 * Call the initialization functions for each of the objects in
2025 * "list". All of the objects are expected to have non-NULL init
2029 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2034 Elf_Addr *init_addr;
2038 * Clean init_scanned flag so that objects can be rechecked and
2039 * possibly initialized earlier if any of vectors called below
2040 * cause the change by using dlopen.
2042 for (obj = obj_list; obj != NULL; obj = obj->next)
2043 obj->init_scanned = false;
2046 * Preserve the current error message since an init function might
2047 * call into the dynamic linker and overwrite it.
2049 saved_msg = errmsg_save();
2050 STAILQ_FOREACH(elm, list, link) {
2051 if (elm->obj->init_done) /* Initialized early. */
2054 * Race: other thread might try to use this object before current
2055 * one completes the initilization. Not much can be done here
2056 * without better locking.
2058 elm->obj->init_done = true;
2059 lock_release(rtld_bind_lock, lockstate);
2062 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2063 * When this happens, DT_INIT is processed first.
2065 if (elm->obj->init != (Elf_Addr)NULL) {
2066 dbg("calling init function for %s at %p", elm->obj->path,
2067 (void *)elm->obj->init);
2068 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2069 0, 0, elm->obj->path);
2070 call_initfini_pointer(elm->obj, elm->obj->init);
2072 init_addr = (Elf_Addr *)elm->obj->init_array;
2073 if (init_addr != NULL) {
2074 for (index = 0; index < elm->obj->init_array_num; index++) {
2075 if (init_addr[index] != 0 && init_addr[index] != 1) {
2076 dbg("calling init function for %s at %p", elm->obj->path,
2077 (void *)init_addr[index]);
2078 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2079 (void *)init_addr[index], 0, 0, elm->obj->path);
2080 call_init_pointer(elm->obj, init_addr[index]);
2084 wlock_acquire(rtld_bind_lock, lockstate);
2086 errmsg_restore(saved_msg);
2090 objlist_clear(Objlist *list)
2094 while (!STAILQ_EMPTY(list)) {
2095 elm = STAILQ_FIRST(list);
2096 STAILQ_REMOVE_HEAD(list, link);
2101 static Objlist_Entry *
2102 objlist_find(Objlist *list, const Obj_Entry *obj)
2106 STAILQ_FOREACH(elm, list, link)
2107 if (elm->obj == obj)
2113 objlist_init(Objlist *list)
2119 objlist_push_head(Objlist *list, Obj_Entry *obj)
2123 elm = NEW(Objlist_Entry);
2125 STAILQ_INSERT_HEAD(list, elm, link);
2129 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2133 elm = NEW(Objlist_Entry);
2135 STAILQ_INSERT_TAIL(list, elm, link);
2139 objlist_remove(Objlist *list, Obj_Entry *obj)
2143 if ((elm = objlist_find(list, obj)) != NULL) {
2144 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2150 * Relocate newly-loaded shared objects. The argument is a pointer to
2151 * the Obj_Entry for the first such object. All objects from the first
2152 * to the end of the list of objects are relocated. Returns 0 on success,
2156 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2157 int flags, RtldLockState *lockstate)
2161 for (obj = first; obj != NULL; obj = obj->next) {
2164 obj->relocated = true;
2166 dbg("relocating \"%s\"", obj->path);
2168 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
2169 obj->symtab == NULL || obj->strtab == NULL) {
2170 _rtld_error("%s: Shared object has no run-time symbol table",
2176 /* There are relocations to the write-protected text segment. */
2177 if (mprotect(obj->mapbase, obj->textsize,
2178 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2179 _rtld_error("%s: Cannot write-enable text segment: %s",
2180 obj->path, rtld_strerror(errno));
2185 /* Process the non-PLT relocations. */
2186 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2189 if (obj->textrel) { /* Re-protected the text segment. */
2190 if (mprotect(obj->mapbase, obj->textsize,
2191 PROT_READ|PROT_EXEC) == -1) {
2192 _rtld_error("%s: Cannot write-protect text segment: %s",
2193 obj->path, rtld_strerror(errno));
2199 /* Set the special PLT or GOT entries. */
2202 /* Process the PLT relocations. */
2203 if (reloc_plt(obj) == -1)
2205 /* Relocate the jump slots if we are doing immediate binding. */
2206 if (obj->bind_now || bind_now)
2207 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2210 if (obj->relro_size > 0) {
2211 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
2212 _rtld_error("%s: Cannot enforce relro protection: %s",
2213 obj->path, rtld_strerror(errno));
2219 * Set up the magic number and version in the Obj_Entry. These
2220 * were checked in the crt1.o from the original ElfKit, so we
2221 * set them for backward compatibility.
2223 obj->magic = RTLD_MAGIC;
2224 obj->version = RTLD_VERSION;
2231 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2232 * referencing STT_GNU_IFUNC symbols is postponed till the other
2233 * relocations are done. The indirect functions specified as
2234 * ifunc are allowed to call other symbols, so we need to have
2235 * objects relocated before asking for resolution from indirects.
2237 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2238 * instead of the usual lazy handling of PLT slots. It is
2239 * consistent with how GNU does it.
2242 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2243 RtldLockState *lockstate)
2245 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2247 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2248 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2254 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2255 RtldLockState *lockstate)
2259 for (obj = first; obj != NULL; obj = obj->next) {
2260 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2267 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2268 RtldLockState *lockstate)
2272 STAILQ_FOREACH(elm, list, link) {
2273 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2281 * Cleanup procedure. It will be called (by the atexit mechanism) just
2282 * before the process exits.
2287 RtldLockState lockstate;
2289 wlock_acquire(rtld_bind_lock, &lockstate);
2291 objlist_call_fini(&list_fini, NULL, &lockstate);
2292 /* No need to remove the items from the list, since we are exiting. */
2293 if (!libmap_disable)
2295 lock_release(rtld_bind_lock, &lockstate);
2299 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2307 path += strspn(path, ":;");
2308 while (*path != '\0') {
2312 len = strcspn(path, ":;");
2314 trans = lm_findn(NULL, path, len);
2316 res = callback(trans, strlen(trans), arg);
2319 res = callback(path, len, arg);
2325 path += strspn(path, ":;");
2331 struct try_library_args {
2339 try_library_path(const char *dir, size_t dirlen, void *param)
2341 struct try_library_args *arg;
2344 if (*dir == '/' || trust) {
2347 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2350 pathname = arg->buffer;
2351 strncpy(pathname, dir, dirlen);
2352 pathname[dirlen] = '/';
2353 strcpy(pathname + dirlen + 1, arg->name);
2355 dbg(" Trying \"%s\"", pathname);
2356 if (access(pathname, F_OK) == 0) { /* We found it */
2357 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2358 strcpy(pathname, arg->buffer);
2366 search_library_path(const char *name, const char *path)
2369 struct try_library_args arg;
2375 arg.namelen = strlen(name);
2376 arg.buffer = xmalloc(PATH_MAX);
2377 arg.buflen = PATH_MAX;
2379 p = path_enumerate(path, try_library_path, &arg);
2387 dlclose(void *handle)
2390 RtldLockState lockstate;
2392 wlock_acquire(rtld_bind_lock, &lockstate);
2393 root = dlcheck(handle);
2395 lock_release(rtld_bind_lock, &lockstate);
2398 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2401 /* Unreference the object and its dependencies. */
2402 root->dl_refcount--;
2404 if (root->refcount == 1) {
2406 * The object will be no longer referenced, so we must unload it.
2407 * First, call the fini functions.
2409 objlist_call_fini(&list_fini, root, &lockstate);
2413 /* Finish cleaning up the newly-unreferenced objects. */
2414 GDB_STATE(RT_DELETE,&root->linkmap);
2415 unload_object(root);
2416 GDB_STATE(RT_CONSISTENT,NULL);
2420 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2421 lock_release(rtld_bind_lock, &lockstate);
2428 char *msg = error_message;
2429 error_message = NULL;
2434 * This function is deprecated and has no effect.
2437 dllockinit(void *context,
2438 void *(*lock_create)(void *context),
2439 void (*rlock_acquire)(void *lock),
2440 void (*wlock_acquire)(void *lock),
2441 void (*lock_release)(void *lock),
2442 void (*lock_destroy)(void *lock),
2443 void (*context_destroy)(void *context))
2445 static void *cur_context;
2446 static void (*cur_context_destroy)(void *);
2448 /* Just destroy the context from the previous call, if necessary. */
2449 if (cur_context_destroy != NULL)
2450 cur_context_destroy(cur_context);
2451 cur_context = context;
2452 cur_context_destroy = context_destroy;
2456 dlopen(const char *name, int mode)
2459 return (rtld_dlopen(name, -1, mode));
2463 fdlopen(int fd, int mode)
2466 return (rtld_dlopen(NULL, fd, mode));
2470 rtld_dlopen(const char *name, int fd, int mode)
2472 RtldLockState lockstate;
2475 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2476 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2477 if (ld_tracing != NULL) {
2478 rlock_acquire(rtld_bind_lock, &lockstate);
2479 if (sigsetjmp(lockstate.env, 0) != 0)
2480 lock_upgrade(rtld_bind_lock, &lockstate);
2481 environ = (char **)*get_program_var_addr("environ", &lockstate);
2482 lock_release(rtld_bind_lock, &lockstate);
2484 lo_flags = RTLD_LO_DLOPEN;
2485 if (mode & RTLD_NODELETE)
2486 lo_flags |= RTLD_LO_NODELETE;
2487 if (mode & RTLD_NOLOAD)
2488 lo_flags |= RTLD_LO_NOLOAD;
2489 if (ld_tracing != NULL)
2490 lo_flags |= RTLD_LO_TRACE;
2492 return (dlopen_object(name, fd, obj_main, lo_flags,
2493 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2497 dlopen_cleanup(Obj_Entry *obj)
2502 if (obj->refcount == 0)
2507 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2508 int mode, RtldLockState *lockstate)
2510 Obj_Entry **old_obj_tail;
2513 RtldLockState mlockstate;
2516 objlist_init(&initlist);
2518 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2519 wlock_acquire(rtld_bind_lock, &mlockstate);
2520 lockstate = &mlockstate;
2522 GDB_STATE(RT_ADD,NULL);
2524 old_obj_tail = obj_tail;
2526 if (name == NULL && fd == -1) {
2530 obj = load_object(name, fd, refobj, lo_flags);
2535 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2536 objlist_push_tail(&list_global, obj);
2537 if (*old_obj_tail != NULL) { /* We loaded something new. */
2538 assert(*old_obj_tail == obj);
2539 result = load_needed_objects(obj,
2540 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2544 result = rtld_verify_versions(&obj->dagmembers);
2545 if (result != -1 && ld_tracing)
2547 if (result == -1 || (relocate_objects(obj,
2548 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2549 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2550 lockstate)) == -1) {
2551 dlopen_cleanup(obj);
2553 } else if (lo_flags & RTLD_LO_EARLY) {
2555 * Do not call the init functions for early loaded
2556 * filtees. The image is still not initialized enough
2559 * Our object is found by the global object list and
2560 * will be ordered among all init calls done right
2561 * before transferring control to main.
2564 /* Make list of init functions to call. */
2565 initlist_add_objects(obj, &obj->next, &initlist);
2570 * Bump the reference counts for objects on this DAG. If
2571 * this is the first dlopen() call for the object that was
2572 * already loaded as a dependency, initialize the dag
2578 if ((lo_flags & RTLD_LO_TRACE) != 0)
2581 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2582 obj->z_nodelete) && !obj->ref_nodel) {
2583 dbg("obj %s nodelete", obj->path);
2585 obj->z_nodelete = obj->ref_nodel = true;
2589 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2591 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2593 if (!(lo_flags & RTLD_LO_EARLY)) {
2594 map_stacks_exec(lockstate);
2597 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2598 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2600 objlist_clear(&initlist);
2601 dlopen_cleanup(obj);
2602 if (lockstate == &mlockstate)
2603 lock_release(rtld_bind_lock, lockstate);
2607 if (!(lo_flags & RTLD_LO_EARLY)) {
2608 /* Call the init functions. */
2609 objlist_call_init(&initlist, lockstate);
2611 objlist_clear(&initlist);
2612 if (lockstate == &mlockstate)
2613 lock_release(rtld_bind_lock, lockstate);
2616 trace_loaded_objects(obj);
2617 if (lockstate == &mlockstate)
2618 lock_release(rtld_bind_lock, lockstate);
2623 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2627 const Obj_Entry *obj, *defobj;
2630 RtldLockState lockstate;
2638 symlook_init(&req, name);
2640 req.flags = flags | SYMLOOK_IN_PLT;
2641 req.lockstate = &lockstate;
2643 rlock_acquire(rtld_bind_lock, &lockstate);
2644 if (sigsetjmp(lockstate.env, 0) != 0)
2645 lock_upgrade(rtld_bind_lock, &lockstate);
2646 if (handle == NULL || handle == RTLD_NEXT ||
2647 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2649 if ((obj = obj_from_addr(retaddr)) == NULL) {
2650 _rtld_error("Cannot determine caller's shared object");
2651 lock_release(rtld_bind_lock, &lockstate);
2654 if (handle == NULL) { /* Just the caller's shared object. */
2655 res = symlook_obj(&req, obj);
2658 defobj = req.defobj_out;
2660 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2661 handle == RTLD_SELF) { /* ... caller included */
2662 if (handle == RTLD_NEXT)
2664 for (; obj != NULL; obj = obj->next) {
2665 res = symlook_obj(&req, obj);
2668 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2670 defobj = req.defobj_out;
2671 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2677 * Search the dynamic linker itself, and possibly resolve the
2678 * symbol from there. This is how the application links to
2679 * dynamic linker services such as dlopen.
2681 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2682 res = symlook_obj(&req, &obj_rtld);
2685 defobj = req.defobj_out;
2689 assert(handle == RTLD_DEFAULT);
2690 res = symlook_default(&req, obj);
2692 defobj = req.defobj_out;
2697 if ((obj = dlcheck(handle)) == NULL) {
2698 lock_release(rtld_bind_lock, &lockstate);
2702 donelist_init(&donelist);
2703 if (obj->mainprog) {
2704 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
2705 res = symlook_global(&req, &donelist);
2708 defobj = req.defobj_out;
2711 * Search the dynamic linker itself, and possibly resolve the
2712 * symbol from there. This is how the application links to
2713 * dynamic linker services such as dlopen.
2715 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2716 res = symlook_obj(&req, &obj_rtld);
2719 defobj = req.defobj_out;
2724 /* Search the whole DAG rooted at the given object. */
2725 res = symlook_list(&req, &obj->dagmembers, &donelist);
2728 defobj = req.defobj_out;
2734 lock_release(rtld_bind_lock, &lockstate);
2737 * The value required by the caller is derived from the value
2738 * of the symbol. For the ia64 architecture, we need to
2739 * construct a function descriptor which the caller can use to
2740 * call the function with the right 'gp' value. For other
2741 * architectures and for non-functions, the value is simply
2742 * the relocated value of the symbol.
2744 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
2745 return (make_function_pointer(def, defobj));
2746 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
2747 return (rtld_resolve_ifunc(defobj, def));
2748 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
2750 return (__tls_get_addr(defobj->tlsindex, def->st_value));
2752 ti.ti_module = defobj->tlsindex;
2753 ti.ti_offset = def->st_value;
2754 return (__tls_get_addr(&ti));
2757 return (defobj->relocbase + def->st_value);
2760 _rtld_error("Undefined symbol \"%s\"", name);
2761 lock_release(rtld_bind_lock, &lockstate);
2766 dlsym(void *handle, const char *name)
2768 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2773 dlfunc(void *handle, const char *name)
2780 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
2786 dlvsym(void *handle, const char *name, const char *version)
2790 ventry.name = version;
2792 ventry.hash = elf_hash(version);
2794 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2799 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
2801 const Obj_Entry *obj;
2802 RtldLockState lockstate;
2804 rlock_acquire(rtld_bind_lock, &lockstate);
2805 obj = obj_from_addr(addr);
2807 _rtld_error("No shared object contains address");
2808 lock_release(rtld_bind_lock, &lockstate);
2811 rtld_fill_dl_phdr_info(obj, phdr_info);
2812 lock_release(rtld_bind_lock, &lockstate);
2817 dladdr(const void *addr, Dl_info *info)
2819 const Obj_Entry *obj;
2822 unsigned long symoffset;
2823 RtldLockState lockstate;
2825 rlock_acquire(rtld_bind_lock, &lockstate);
2826 obj = obj_from_addr(addr);
2828 _rtld_error("No shared object contains address");
2829 lock_release(rtld_bind_lock, &lockstate);
2832 info->dli_fname = obj->path;
2833 info->dli_fbase = obj->mapbase;
2834 info->dli_saddr = (void *)0;
2835 info->dli_sname = NULL;
2838 * Walk the symbol list looking for the symbol whose address is
2839 * closest to the address sent in.
2841 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
2842 def = obj->symtab + symoffset;
2845 * For skip the symbol if st_shndx is either SHN_UNDEF or
2848 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2852 * If the symbol is greater than the specified address, or if it
2853 * is further away from addr than the current nearest symbol,
2856 symbol_addr = obj->relocbase + def->st_value;
2857 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2860 /* Update our idea of the nearest symbol. */
2861 info->dli_sname = obj->strtab + def->st_name;
2862 info->dli_saddr = symbol_addr;
2865 if (info->dli_saddr == addr)
2868 lock_release(rtld_bind_lock, &lockstate);
2873 dlinfo(void *handle, int request, void *p)
2875 const Obj_Entry *obj;
2876 RtldLockState lockstate;
2879 rlock_acquire(rtld_bind_lock, &lockstate);
2881 if (handle == NULL || handle == RTLD_SELF) {
2884 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2885 if ((obj = obj_from_addr(retaddr)) == NULL)
2886 _rtld_error("Cannot determine caller's shared object");
2888 obj = dlcheck(handle);
2891 lock_release(rtld_bind_lock, &lockstate);
2897 case RTLD_DI_LINKMAP:
2898 *((struct link_map const **)p) = &obj->linkmap;
2900 case RTLD_DI_ORIGIN:
2901 error = rtld_dirname(obj->path, p);
2904 case RTLD_DI_SERINFOSIZE:
2905 case RTLD_DI_SERINFO:
2906 error = do_search_info(obj, request, (struct dl_serinfo *)p);
2910 _rtld_error("Invalid request %d passed to dlinfo()", request);
2914 lock_release(rtld_bind_lock, &lockstate);
2920 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
2923 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
2924 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
2925 STAILQ_FIRST(&obj->names)->name : obj->path;
2926 phdr_info->dlpi_phdr = obj->phdr;
2927 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
2928 phdr_info->dlpi_tls_modid = obj->tlsindex;
2929 phdr_info->dlpi_tls_data = obj->tlsinit;
2930 phdr_info->dlpi_adds = obj_loads;
2931 phdr_info->dlpi_subs = obj_loads - obj_count;
2935 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
2937 struct dl_phdr_info phdr_info;
2938 const Obj_Entry *obj;
2939 RtldLockState bind_lockstate, phdr_lockstate;
2942 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
2943 rlock_acquire(rtld_bind_lock, &bind_lockstate);
2947 for (obj = obj_list; obj != NULL; obj = obj->next) {
2948 rtld_fill_dl_phdr_info(obj, &phdr_info);
2949 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
2953 lock_release(rtld_bind_lock, &bind_lockstate);
2954 lock_release(rtld_phdr_lock, &phdr_lockstate);
2959 struct fill_search_info_args {
2962 Dl_serinfo *serinfo;
2963 Dl_serpath *serpath;
2968 fill_search_info(const char *dir, size_t dirlen, void *param)
2970 struct fill_search_info_args *arg;
2974 if (arg->request == RTLD_DI_SERINFOSIZE) {
2975 arg->serinfo->dls_cnt ++;
2976 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
2978 struct dl_serpath *s_entry;
2980 s_entry = arg->serpath;
2981 s_entry->dls_name = arg->strspace;
2982 s_entry->dls_flags = arg->flags;
2984 strncpy(arg->strspace, dir, dirlen);
2985 arg->strspace[dirlen] = '\0';
2987 arg->strspace += dirlen + 1;
2995 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2997 struct dl_serinfo _info;
2998 struct fill_search_info_args args;
3000 args.request = RTLD_DI_SERINFOSIZE;
3001 args.serinfo = &_info;
3003 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3006 path_enumerate(ld_library_path, fill_search_info, &args);
3007 path_enumerate(obj->rpath, fill_search_info, &args);
3008 path_enumerate(gethints(), fill_search_info, &args);
3009 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3012 if (request == RTLD_DI_SERINFOSIZE) {
3013 info->dls_size = _info.dls_size;
3014 info->dls_cnt = _info.dls_cnt;
3018 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3019 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3023 args.request = RTLD_DI_SERINFO;
3024 args.serinfo = info;
3025 args.serpath = &info->dls_serpath[0];
3026 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3028 args.flags = LA_SER_LIBPATH;
3029 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3032 args.flags = LA_SER_RUNPATH;
3033 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3036 args.flags = LA_SER_CONFIG;
3037 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
3040 args.flags = LA_SER_DEFAULT;
3041 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3047 rtld_dirname(const char *path, char *bname)
3051 /* Empty or NULL string gets treated as "." */
3052 if (path == NULL || *path == '\0') {
3058 /* Strip trailing slashes */
3059 endp = path + strlen(path) - 1;
3060 while (endp > path && *endp == '/')
3063 /* Find the start of the dir */
3064 while (endp > path && *endp != '/')
3067 /* Either the dir is "/" or there are no slashes */
3069 bname[0] = *endp == '/' ? '/' : '.';
3075 } while (endp > path && *endp == '/');
3078 if (endp - path + 2 > PATH_MAX)
3080 _rtld_error("Filename is too long: %s", path);
3084 strncpy(bname, path, endp - path + 1);
3085 bname[endp - path + 1] = '\0';
3090 rtld_dirname_abs(const char *path, char *base)
3092 char base_rel[PATH_MAX];
3094 if (rtld_dirname(path, base) == -1)
3098 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3099 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3100 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3102 strcpy(base, base_rel);
3107 linkmap_add(Obj_Entry *obj)
3109 struct link_map *l = &obj->linkmap;
3110 struct link_map *prev;
3112 obj->linkmap.l_name = obj->path;
3113 obj->linkmap.l_addr = obj->mapbase;
3114 obj->linkmap.l_ld = obj->dynamic;
3116 /* GDB needs load offset on MIPS to use the symbols */
3117 obj->linkmap.l_offs = obj->relocbase;
3120 if (r_debug.r_map == NULL) {
3126 * Scan to the end of the list, but not past the entry for the
3127 * dynamic linker, which we want to keep at the very end.
3129 for (prev = r_debug.r_map;
3130 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3131 prev = prev->l_next)
3134 /* Link in the new entry. */
3136 l->l_next = prev->l_next;
3137 if (l->l_next != NULL)
3138 l->l_next->l_prev = l;
3143 linkmap_delete(Obj_Entry *obj)
3145 struct link_map *l = &obj->linkmap;
3147 if (l->l_prev == NULL) {
3148 if ((r_debug.r_map = l->l_next) != NULL)
3149 l->l_next->l_prev = NULL;
3153 if ((l->l_prev->l_next = l->l_next) != NULL)
3154 l->l_next->l_prev = l->l_prev;
3158 * Function for the debugger to set a breakpoint on to gain control.
3160 * The two parameters allow the debugger to easily find and determine
3161 * what the runtime loader is doing and to whom it is doing it.
3163 * When the loadhook trap is hit (r_debug_state, set at program
3164 * initialization), the arguments can be found on the stack:
3166 * +8 struct link_map *m
3167 * +4 struct r_debug *rd
3171 r_debug_state(struct r_debug* rd, struct link_map *m)
3174 * The following is a hack to force the compiler to emit calls to
3175 * this function, even when optimizing. If the function is empty,
3176 * the compiler is not obliged to emit any code for calls to it,
3177 * even when marked __noinline. However, gdb depends on those
3180 __asm __volatile("" : : : "memory");
3184 * Get address of the pointer variable in the main program.
3185 * Prefer non-weak symbol over the weak one.
3187 static const void **
3188 get_program_var_addr(const char *name, RtldLockState *lockstate)
3193 symlook_init(&req, name);
3194 req.lockstate = lockstate;
3195 donelist_init(&donelist);
3196 if (symlook_global(&req, &donelist) != 0)
3198 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3199 return ((const void **)make_function_pointer(req.sym_out,
3201 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3202 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3204 return ((const void **)(req.defobj_out->relocbase +
3205 req.sym_out->st_value));
3209 * Set a pointer variable in the main program to the given value. This
3210 * is used to set key variables such as "environ" before any of the
3211 * init functions are called.
3214 set_program_var(const char *name, const void *value)
3218 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3219 dbg("\"%s\": *%p <-- %p", name, addr, value);
3225 * Search the global objects, including dependencies and main object,
3226 * for the given symbol.
3229 symlook_global(SymLook *req, DoneList *donelist)
3232 const Objlist_Entry *elm;
3235 symlook_init_from_req(&req1, req);
3237 /* Search all objects loaded at program start up. */
3238 if (req->defobj_out == NULL ||
3239 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3240 res = symlook_list(&req1, &list_main, donelist);
3241 if (res == 0 && (req->defobj_out == NULL ||
3242 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3243 req->sym_out = req1.sym_out;
3244 req->defobj_out = req1.defobj_out;
3245 assert(req->defobj_out != NULL);
3249 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3250 STAILQ_FOREACH(elm, &list_global, link) {
3251 if (req->defobj_out != NULL &&
3252 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3254 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3255 if (res == 0 && (req->defobj_out == NULL ||
3256 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3257 req->sym_out = req1.sym_out;
3258 req->defobj_out = req1.defobj_out;
3259 assert(req->defobj_out != NULL);
3263 return (req->sym_out != NULL ? 0 : ESRCH);
3267 * Given a symbol name in a referencing object, find the corresponding
3268 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3269 * no definition was found. Returns a pointer to the Obj_Entry of the
3270 * defining object via the reference parameter DEFOBJ_OUT.
3273 symlook_default(SymLook *req, const Obj_Entry *refobj)
3276 const Objlist_Entry *elm;
3280 donelist_init(&donelist);
3281 symlook_init_from_req(&req1, req);
3283 /* Look first in the referencing object if linked symbolically. */
3284 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3285 res = symlook_obj(&req1, refobj);
3287 req->sym_out = req1.sym_out;
3288 req->defobj_out = req1.defobj_out;
3289 assert(req->defobj_out != NULL);
3293 symlook_global(req, &donelist);
3295 /* Search all dlopened DAGs containing the referencing object. */
3296 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3297 if (req->sym_out != NULL &&
3298 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3300 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3301 if (res == 0 && (req->sym_out == NULL ||
3302 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3303 req->sym_out = req1.sym_out;
3304 req->defobj_out = req1.defobj_out;
3305 assert(req->defobj_out != NULL);
3310 * Search the dynamic linker itself, and possibly resolve the
3311 * symbol from there. This is how the application links to
3312 * dynamic linker services such as dlopen.
3314 if (req->sym_out == NULL ||
3315 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3316 res = symlook_obj(&req1, &obj_rtld);
3318 req->sym_out = req1.sym_out;
3319 req->defobj_out = req1.defobj_out;
3320 assert(req->defobj_out != NULL);
3324 return (req->sym_out != NULL ? 0 : ESRCH);
3328 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3331 const Obj_Entry *defobj;
3332 const Objlist_Entry *elm;
3338 STAILQ_FOREACH(elm, objlist, link) {
3339 if (donelist_check(dlp, elm->obj))
3341 symlook_init_from_req(&req1, req);
3342 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3343 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3345 defobj = req1.defobj_out;
3346 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3353 req->defobj_out = defobj;
3360 * Search the chain of DAGS cointed to by the given Needed_Entry
3361 * for a symbol of the given name. Each DAG is scanned completely
3362 * before advancing to the next one. Returns a pointer to the symbol,
3363 * or NULL if no definition was found.
3366 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3369 const Needed_Entry *n;
3370 const Obj_Entry *defobj;
3376 symlook_init_from_req(&req1, req);
3377 for (n = needed; n != NULL; n = n->next) {
3378 if (n->obj == NULL ||
3379 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3381 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3383 defobj = req1.defobj_out;
3384 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3390 req->defobj_out = defobj;
3397 * Search the symbol table of a single shared object for a symbol of
3398 * the given name and version, if requested. Returns a pointer to the
3399 * symbol, or NULL if no definition was found. If the object is
3400 * filter, return filtered symbol from filtee.
3402 * The symbol's hash value is passed in for efficiency reasons; that
3403 * eliminates many recomputations of the hash value.
3406 symlook_obj(SymLook *req, const Obj_Entry *obj)
3410 int flags, res, mres;
3412 mres = symlook_obj1(req, obj);
3414 if (obj->needed_filtees != NULL) {
3415 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3416 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3417 donelist_init(&donelist);
3418 symlook_init_from_req(&req1, req);
3419 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3421 req->sym_out = req1.sym_out;
3422 req->defobj_out = req1.defobj_out;
3426 if (obj->needed_aux_filtees != NULL) {
3427 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3428 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3429 donelist_init(&donelist);
3430 symlook_init_from_req(&req1, req);
3431 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3433 req->sym_out = req1.sym_out;
3434 req->defobj_out = req1.defobj_out;
3443 symlook_obj1(SymLook *req, const Obj_Entry *obj)
3445 unsigned long symnum;
3446 const Elf_Sym *vsymp;
3450 if (obj->buckets == NULL)
3455 symnum = obj->buckets[req->hash % obj->nbuckets];
3457 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3458 const Elf_Sym *symp;
3461 if (symnum >= obj->nchains)
3462 return (ESRCH); /* Bad object */
3464 symp = obj->symtab + symnum;
3465 strp = obj->strtab + symp->st_name;
3467 switch (ELF_ST_TYPE(symp->st_info)) {
3472 if (symp->st_value == 0)
3476 if (symp->st_shndx != SHN_UNDEF)
3479 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3480 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3487 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3490 if (req->ventry == NULL) {
3491 if (obj->versyms != NULL) {
3492 verndx = VER_NDX(obj->versyms[symnum]);
3493 if (verndx > obj->vernum) {
3494 _rtld_error("%s: symbol %s references wrong version %d",
3495 obj->path, obj->strtab + symnum, verndx);
3499 * If we are not called from dlsym (i.e. this is a normal
3500 * relocation from unversioned binary), accept the symbol
3501 * immediately if it happens to have first version after
3502 * this shared object became versioned. Otherwise, if
3503 * symbol is versioned and not hidden, remember it. If it
3504 * is the only symbol with this name exported by the
3505 * shared object, it will be returned as a match at the
3506 * end of the function. If symbol is global (verndx < 2)
3507 * accept it unconditionally.
3509 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3510 verndx == VER_NDX_GIVEN) {
3511 req->sym_out = symp;
3512 req->defobj_out = obj;
3515 else if (verndx >= VER_NDX_GIVEN) {
3516 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
3524 req->sym_out = symp;
3525 req->defobj_out = obj;
3528 if (obj->versyms == NULL) {
3529 if (object_match_name(obj, req->ventry->name)) {
3530 _rtld_error("%s: object %s should provide version %s for "
3531 "symbol %s", obj_rtld.path, obj->path,
3532 req->ventry->name, obj->strtab + symnum);
3536 verndx = VER_NDX(obj->versyms[symnum]);
3537 if (verndx > obj->vernum) {
3538 _rtld_error("%s: symbol %s references wrong version %d",
3539 obj->path, obj->strtab + symnum, verndx);
3542 if (obj->vertab[verndx].hash != req->ventry->hash ||
3543 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3545 * Version does not match. Look if this is a global symbol
3546 * and if it is not hidden. If global symbol (verndx < 2)
3547 * is available, use it. Do not return symbol if we are
3548 * called by dlvsym, because dlvsym looks for a specific
3549 * version and default one is not what dlvsym wants.
3551 if ((req->flags & SYMLOOK_DLSYM) ||
3552 (obj->versyms[symnum] & VER_NDX_HIDDEN) ||
3553 (verndx >= VER_NDX_GIVEN))
3557 req->sym_out = symp;
3558 req->defobj_out = obj;
3563 req->sym_out = vsymp;
3564 req->defobj_out = obj;
3571 trace_loaded_objects(Obj_Entry *obj)
3573 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3576 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3579 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3580 fmt1 = "\t%o => %p (%x)\n";
3582 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3583 fmt2 = "\t%o (%x)\n";
3585 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
3587 for (; obj; obj = obj->next) {
3588 Needed_Entry *needed;
3592 if (list_containers && obj->needed != NULL)
3593 rtld_printf("%s:\n", obj->path);
3594 for (needed = obj->needed; needed; needed = needed->next) {
3595 if (needed->obj != NULL) {
3596 if (needed->obj->traced && !list_containers)
3598 needed->obj->traced = true;
3599 path = needed->obj->path;
3603 name = (char *)obj->strtab + needed->name;
3604 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3606 fmt = is_lib ? fmt1 : fmt2;
3607 while ((c = *fmt++) != '\0') {
3633 rtld_putstr(main_local);
3636 rtld_putstr(obj_main->path);
3643 rtld_printf("%d", sodp->sod_major);
3646 rtld_printf("%d", sodp->sod_minor);
3653 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
3666 * Unload a dlopened object and its dependencies from memory and from
3667 * our data structures. It is assumed that the DAG rooted in the
3668 * object has already been unreferenced, and that the object has a
3669 * reference count of 0.
3672 unload_object(Obj_Entry *root)
3677 assert(root->refcount == 0);
3680 * Pass over the DAG removing unreferenced objects from
3681 * appropriate lists.
3683 unlink_object(root);
3685 /* Unmap all objects that are no longer referenced. */
3686 linkp = &obj_list->next;
3687 while ((obj = *linkp) != NULL) {
3688 if (obj->refcount == 0) {
3689 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3691 dbg("unloading \"%s\"", obj->path);
3692 unload_filtees(root);
3693 munmap(obj->mapbase, obj->mapsize);
3694 linkmap_delete(obj);
3705 unlink_object(Obj_Entry *root)
3709 if (root->refcount == 0) {
3710 /* Remove the object from the RTLD_GLOBAL list. */
3711 objlist_remove(&list_global, root);
3713 /* Remove the object from all objects' DAG lists. */
3714 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3715 objlist_remove(&elm->obj->dldags, root);
3716 if (elm->obj != root)
3717 unlink_object(elm->obj);
3723 ref_dag(Obj_Entry *root)
3727 assert(root->dag_inited);
3728 STAILQ_FOREACH(elm, &root->dagmembers, link)
3729 elm->obj->refcount++;
3733 unref_dag(Obj_Entry *root)
3737 assert(root->dag_inited);
3738 STAILQ_FOREACH(elm, &root->dagmembers, link)
3739 elm->obj->refcount--;
3743 * Common code for MD __tls_get_addr().
3745 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
3747 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
3749 Elf_Addr *newdtv, *dtv;
3750 RtldLockState lockstate;
3754 /* Check dtv generation in case new modules have arrived */
3755 if (dtv[0] != tls_dtv_generation) {
3756 wlock_acquire(rtld_bind_lock, &lockstate);
3757 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
3759 if (to_copy > tls_max_index)
3760 to_copy = tls_max_index;
3761 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
3762 newdtv[0] = tls_dtv_generation;
3763 newdtv[1] = tls_max_index;
3765 lock_release(rtld_bind_lock, &lockstate);
3766 dtv = *dtvp = newdtv;
3769 /* Dynamically allocate module TLS if necessary */
3770 if (dtv[index + 1] == 0) {
3771 /* Signal safe, wlock will block out signals. */
3772 wlock_acquire(rtld_bind_lock, &lockstate);
3773 if (!dtv[index + 1])
3774 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
3775 lock_release(rtld_bind_lock, &lockstate);
3777 return ((void *)(dtv[index + 1] + offset));
3781 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
3786 /* Check dtv generation in case new modules have arrived */
3787 if (__predict_true(dtv[0] == tls_dtv_generation &&
3788 dtv[index + 1] != 0))
3789 return ((void *)(dtv[index + 1] + offset));
3790 return (tls_get_addr_slow(dtvp, index, offset));
3793 /* XXX not sure what variants to use for arm. */
3795 #if defined(__ia64__) || defined(__powerpc__)
3798 * Allocate Static TLS using the Variant I method.
3801 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
3810 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
3813 assert(tcbsize >= TLS_TCB_SIZE);
3814 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
3815 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
3817 if (oldtcb != NULL) {
3818 memcpy(tls, oldtcb, tls_static_space);
3821 /* Adjust the DTV. */
3823 for (i = 0; i < dtv[1]; i++) {
3824 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
3825 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
3826 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
3830 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
3832 dtv[0] = tls_dtv_generation;
3833 dtv[1] = tls_max_index;
3835 for (obj = objs; obj; obj = obj->next) {
3836 if (obj->tlsoffset > 0) {
3837 addr = (Elf_Addr)tls + obj->tlsoffset;
3838 if (obj->tlsinitsize > 0)
3839 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3840 if (obj->tlssize > obj->tlsinitsize)
3841 memset((void*) (addr + obj->tlsinitsize), 0,
3842 obj->tlssize - obj->tlsinitsize);
3843 dtv[obj->tlsindex + 1] = addr;
3852 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
3855 Elf_Addr tlsstart, tlsend;
3858 assert(tcbsize >= TLS_TCB_SIZE);
3860 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
3861 tlsend = tlsstart + tls_static_space;
3863 dtv = *(Elf_Addr **)tlsstart;
3865 for (i = 0; i < dtvsize; i++) {
3866 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
3867 free((void*)dtv[i+2]);
3876 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
3877 defined(__arm__) || defined(__mips__)
3880 * Allocate Static TLS using the Variant II method.
3883 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
3888 Elf_Addr *dtv, *olddtv;
3889 Elf_Addr segbase, oldsegbase, addr;
3892 size = round(tls_static_space, tcbalign);
3894 assert(tcbsize >= 2*sizeof(Elf_Addr));
3895 tls = xcalloc(1, size + tcbsize);
3896 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
3898 segbase = (Elf_Addr)(tls + size);
3899 ((Elf_Addr*)segbase)[0] = segbase;
3900 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
3902 dtv[0] = tls_dtv_generation;
3903 dtv[1] = tls_max_index;
3907 * Copy the static TLS block over whole.
3909 oldsegbase = (Elf_Addr) oldtls;
3910 memcpy((void *)(segbase - tls_static_space),
3911 (const void *)(oldsegbase - tls_static_space),
3915 * If any dynamic TLS blocks have been created tls_get_addr(),
3918 olddtv = ((Elf_Addr**)oldsegbase)[1];
3919 for (i = 0; i < olddtv[1]; i++) {
3920 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
3921 dtv[i+2] = olddtv[i+2];
3927 * We assume that this block was the one we created with
3928 * allocate_initial_tls().
3930 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
3932 for (obj = objs; obj; obj = obj->next) {
3933 if (obj->tlsoffset) {
3934 addr = segbase - obj->tlsoffset;
3935 memset((void*) (addr + obj->tlsinitsize),
3936 0, obj->tlssize - obj->tlsinitsize);
3938 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3939 dtv[obj->tlsindex + 1] = addr;
3944 return (void*) segbase;
3948 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
3953 Elf_Addr tlsstart, tlsend;
3956 * Figure out the size of the initial TLS block so that we can
3957 * find stuff which ___tls_get_addr() allocated dynamically.
3959 size = round(tls_static_space, tcbalign);
3961 dtv = ((Elf_Addr**)tls)[1];
3963 tlsend = (Elf_Addr) tls;
3964 tlsstart = tlsend - size;
3965 for (i = 0; i < dtvsize; i++) {
3966 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
3967 free((void*) dtv[i+2]);
3971 free((void*) tlsstart);
3978 * Allocate TLS block for module with given index.
3981 allocate_module_tls(int index)
3986 for (obj = obj_list; obj; obj = obj->next) {
3987 if (obj->tlsindex == index)
3991 _rtld_error("Can't find module with TLS index %d", index);
3995 p = malloc(obj->tlssize);
3997 _rtld_error("Cannot allocate TLS block for index %d", index);
4000 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4001 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4007 allocate_tls_offset(Obj_Entry *obj)
4014 if (obj->tlssize == 0) {
4015 obj->tls_done = true;
4019 if (obj->tlsindex == 1)
4020 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4022 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4023 obj->tlssize, obj->tlsalign);
4026 * If we have already fixed the size of the static TLS block, we
4027 * must stay within that size. When allocating the static TLS, we
4028 * leave a small amount of space spare to be used for dynamically
4029 * loading modules which use static TLS.
4031 if (tls_static_space) {
4032 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4036 tls_last_offset = obj->tlsoffset = off;
4037 tls_last_size = obj->tlssize;
4038 obj->tls_done = true;
4044 free_tls_offset(Obj_Entry *obj)
4048 * If we were the last thing to allocate out of the static TLS
4049 * block, we give our space back to the 'allocator'. This is a
4050 * simplistic workaround to allow libGL.so.1 to be loaded and
4051 * unloaded multiple times.
4053 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4054 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4055 tls_last_offset -= obj->tlssize;
4061 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4064 RtldLockState lockstate;
4066 wlock_acquire(rtld_bind_lock, &lockstate);
4067 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4068 lock_release(rtld_bind_lock, &lockstate);
4073 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4075 RtldLockState lockstate;
4077 wlock_acquire(rtld_bind_lock, &lockstate);
4078 free_tls(tcb, tcbsize, tcbalign);
4079 lock_release(rtld_bind_lock, &lockstate);
4083 object_add_name(Obj_Entry *obj, const char *name)
4089 entry = malloc(sizeof(Name_Entry) + len);
4091 if (entry != NULL) {
4092 strcpy(entry->name, name);
4093 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4098 object_match_name(const Obj_Entry *obj, const char *name)
4102 STAILQ_FOREACH(entry, &obj->names, link) {
4103 if (strcmp(name, entry->name) == 0)
4110 locate_dependency(const Obj_Entry *obj, const char *name)
4112 const Objlist_Entry *entry;
4113 const Needed_Entry *needed;
4115 STAILQ_FOREACH(entry, &list_main, link) {
4116 if (object_match_name(entry->obj, name))
4120 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4121 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4122 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4124 * If there is DT_NEEDED for the name we are looking for,
4125 * we are all set. Note that object might not be found if
4126 * dependency was not loaded yet, so the function can
4127 * return NULL here. This is expected and handled
4128 * properly by the caller.
4130 return (needed->obj);
4133 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4139 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4140 const Elf_Vernaux *vna)
4142 const Elf_Verdef *vd;
4143 const char *vername;
4145 vername = refobj->strtab + vna->vna_name;
4146 vd = depobj->verdef;
4148 _rtld_error("%s: version %s required by %s not defined",
4149 depobj->path, vername, refobj->path);
4153 if (vd->vd_version != VER_DEF_CURRENT) {
4154 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4155 depobj->path, vd->vd_version);
4158 if (vna->vna_hash == vd->vd_hash) {
4159 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4160 ((char *)vd + vd->vd_aux);
4161 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4164 if (vd->vd_next == 0)
4166 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4168 if (vna->vna_flags & VER_FLG_WEAK)
4170 _rtld_error("%s: version %s required by %s not found",
4171 depobj->path, vername, refobj->path);
4176 rtld_verify_object_versions(Obj_Entry *obj)
4178 const Elf_Verneed *vn;
4179 const Elf_Verdef *vd;
4180 const Elf_Verdaux *vda;
4181 const Elf_Vernaux *vna;
4182 const Obj_Entry *depobj;
4183 int maxvernum, vernum;
4185 if (obj->ver_checked)
4187 obj->ver_checked = true;
4191 * Walk over defined and required version records and figure out
4192 * max index used by any of them. Do very basic sanity checking
4196 while (vn != NULL) {
4197 if (vn->vn_version != VER_NEED_CURRENT) {
4198 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4199 obj->path, vn->vn_version);
4202 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4204 vernum = VER_NEED_IDX(vna->vna_other);
4205 if (vernum > maxvernum)
4207 if (vna->vna_next == 0)
4209 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4211 if (vn->vn_next == 0)
4213 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4217 while (vd != NULL) {
4218 if (vd->vd_version != VER_DEF_CURRENT) {
4219 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4220 obj->path, vd->vd_version);
4223 vernum = VER_DEF_IDX(vd->vd_ndx);
4224 if (vernum > maxvernum)
4226 if (vd->vd_next == 0)
4228 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4235 * Store version information in array indexable by version index.
4236 * Verify that object version requirements are satisfied along the
4239 obj->vernum = maxvernum + 1;
4240 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4243 while (vd != NULL) {
4244 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4245 vernum = VER_DEF_IDX(vd->vd_ndx);
4246 assert(vernum <= maxvernum);
4247 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4248 obj->vertab[vernum].hash = vd->vd_hash;
4249 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4250 obj->vertab[vernum].file = NULL;
4251 obj->vertab[vernum].flags = 0;
4253 if (vd->vd_next == 0)
4255 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4259 while (vn != NULL) {
4260 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4263 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4265 if (check_object_provided_version(obj, depobj, vna))
4267 vernum = VER_NEED_IDX(vna->vna_other);
4268 assert(vernum <= maxvernum);
4269 obj->vertab[vernum].hash = vna->vna_hash;
4270 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4271 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4272 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4273 VER_INFO_HIDDEN : 0;
4274 if (vna->vna_next == 0)
4276 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4278 if (vn->vn_next == 0)
4280 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4286 rtld_verify_versions(const Objlist *objlist)
4288 Objlist_Entry *entry;
4292 STAILQ_FOREACH(entry, objlist, link) {
4294 * Skip dummy objects or objects that have their version requirements
4297 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4299 if (rtld_verify_object_versions(entry->obj) == -1) {
4301 if (ld_tracing == NULL)
4305 if (rc == 0 || ld_tracing != NULL)
4306 rc = rtld_verify_object_versions(&obj_rtld);
4311 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4316 vernum = VER_NDX(obj->versyms[symnum]);
4317 if (vernum >= obj->vernum) {
4318 _rtld_error("%s: symbol %s has wrong verneed value %d",
4319 obj->path, obj->strtab + symnum, vernum);
4320 } else if (obj->vertab[vernum].hash != 0) {
4321 return &obj->vertab[vernum];
4328 _rtld_get_stack_prot(void)
4331 return (stack_prot);
4335 map_stacks_exec(RtldLockState *lockstate)
4337 void (*thr_map_stacks_exec)(void);
4339 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4341 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4342 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4343 if (thr_map_stacks_exec != NULL) {
4344 stack_prot |= PROT_EXEC;
4345 thr_map_stacks_exec();
4350 symlook_init(SymLook *dst, const char *name)
4353 bzero(dst, sizeof(*dst));
4355 dst->hash = elf_hash(name);
4359 symlook_init_from_req(SymLook *dst, const SymLook *src)
4362 dst->name = src->name;
4363 dst->hash = src->hash;
4364 dst->ventry = src->ventry;
4365 dst->flags = src->flags;
4366 dst->defobj_out = NULL;
4367 dst->sym_out = NULL;
4368 dst->lockstate = src->lockstate;
4372 * Overrides for libc_pic-provided functions.
4376 __getosreldate(void)
4386 oid[1] = KERN_OSRELDATE;
4388 len = sizeof(osrel);
4389 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4390 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4402 void (*__cleanup)(void);
4403 int __isthreaded = 0;
4404 int _thread_autoinit_dummy_decl = 1;
4407 * No unresolved symbols for rtld.
4410 __pthread_cxa_finalize(struct dl_phdr_info *a)
4415 __stack_chk_fail(void)
4418 _rtld_error("stack overflow detected; terminated");
4421 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
4427 _rtld_error("buffer overflow detected; terminated");
4432 rtld_strerror(int errnum)
4435 if (errnum < 0 || errnum >= sys_nerr)
4436 return ("Unknown error");
4437 return (sys_errlist[errnum]);