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);
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 *, RtldLockState *);
120 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
121 RtldLockState *lockstate);
122 static int rtld_dirname(const char *, char *);
123 static int rtld_dirname_abs(const char *, char *);
124 static void *rtld_dlopen(const char *name, int fd, int mode);
125 static void rtld_exit(void);
126 static char *search_library_path(const char *, const char *);
127 static const void **get_program_var_addr(const char *, RtldLockState *);
128 static void set_program_var(const char *, const void *);
129 static int symlook_default(SymLook *, const Obj_Entry *refobj);
130 static int symlook_global(SymLook *, DoneList *);
131 static void symlook_init_from_req(SymLook *, const SymLook *);
132 static int symlook_list(SymLook *, const Objlist *, DoneList *);
133 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
134 static int symlook_obj1(SymLook *, const Obj_Entry *);
135 static void trace_loaded_objects(Obj_Entry *);
136 static void unlink_object(Obj_Entry *);
137 static void unload_object(Obj_Entry *);
138 static void unref_dag(Obj_Entry *);
139 static void ref_dag(Obj_Entry *);
140 static int origin_subst_one(char **, const char *, const char *,
141 const char *, char *);
142 static char *origin_subst(const char *, const char *);
143 static void preinit_main(void);
144 static int rtld_verify_versions(const Objlist *);
145 static int rtld_verify_object_versions(Obj_Entry *);
146 static void object_add_name(Obj_Entry *, const char *);
147 static int object_match_name(const Obj_Entry *, const char *);
148 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
149 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
150 struct dl_phdr_info *phdr_info);
152 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
157 static char *error_message; /* Message for dlerror(), or NULL */
158 struct r_debug r_debug; /* for GDB; */
159 static bool libmap_disable; /* Disable libmap */
160 static bool ld_loadfltr; /* Immediate filters processing */
161 static char *libmap_override; /* Maps to use in addition to libmap.conf */
162 static bool trust; /* False for setuid and setgid programs */
163 static bool dangerous_ld_env; /* True if environment variables have been
164 used to affect the libraries loaded */
165 static char *ld_bind_now; /* Environment variable for immediate binding */
166 static char *ld_debug; /* Environment variable for debugging */
167 static char *ld_library_path; /* Environment variable for search path */
168 static char *ld_preload; /* Environment variable for libraries to
170 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
171 static char *ld_tracing; /* Called from ldd to print libs */
172 static char *ld_utrace; /* Use utrace() to log events. */
173 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
174 static Obj_Entry **obj_tail; /* Link field of last object in list */
175 static Obj_Entry *obj_main; /* The main program shared object */
176 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
177 static unsigned int obj_count; /* Number of objects in obj_list */
178 static unsigned int obj_loads; /* Number of objects in obj_list */
180 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
181 STAILQ_HEAD_INITIALIZER(list_global);
182 static Objlist list_main = /* Objects loaded at program startup */
183 STAILQ_HEAD_INITIALIZER(list_main);
184 static Objlist list_fini = /* Objects needing fini() calls */
185 STAILQ_HEAD_INITIALIZER(list_fini);
187 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
189 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
191 extern Elf_Dyn _DYNAMIC;
192 #pragma weak _DYNAMIC
193 #ifndef RTLD_IS_DYNAMIC
194 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
197 int osreldate, pagesize;
199 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
201 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
202 static int max_stack_flags;
205 * Global declarations normally provided by crt1. The dynamic linker is
206 * not built with crt1, so we have to provide them ourselves.
212 * Used to pass argc, argv to init functions.
218 * Globals to control TLS allocation.
220 size_t tls_last_offset; /* Static TLS offset of last module */
221 size_t tls_last_size; /* Static TLS size of last module */
222 size_t tls_static_space; /* Static TLS space allocated */
223 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
224 int tls_max_index = 1; /* Largest module index allocated */
227 * Fill in a DoneList with an allocation large enough to hold all of
228 * the currently-loaded objects. Keep this as a macro since it calls
229 * alloca and we want that to occur within the scope of the caller.
231 #define donelist_init(dlp) \
232 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
233 assert((dlp)->objs != NULL), \
234 (dlp)->num_alloc = obj_count, \
237 #define UTRACE_DLOPEN_START 1
238 #define UTRACE_DLOPEN_STOP 2
239 #define UTRACE_DLCLOSE_START 3
240 #define UTRACE_DLCLOSE_STOP 4
241 #define UTRACE_LOAD_OBJECT 5
242 #define UTRACE_UNLOAD_OBJECT 6
243 #define UTRACE_ADD_RUNDEP 7
244 #define UTRACE_PRELOAD_FINISHED 8
245 #define UTRACE_INIT_CALL 9
246 #define UTRACE_FINI_CALL 10
249 char sig[4]; /* 'RTLD' */
252 void *mapbase; /* Used for 'parent' and 'init/fini' */
254 int refcnt; /* Used for 'mode' */
255 char name[MAXPATHLEN];
258 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
259 if (ld_utrace != NULL) \
260 ld_utrace_log(e, h, mb, ms, r, n); \
264 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
265 int refcnt, const char *name)
267 struct utrace_rtld ut;
275 ut.mapbase = mapbase;
276 ut.mapsize = mapsize;
278 bzero(ut.name, sizeof(ut.name));
280 strlcpy(ut.name, name, sizeof(ut.name));
281 utrace(&ut, sizeof(ut));
285 * Main entry point for dynamic linking. The first argument is the
286 * stack pointer. The stack is expected to be laid out as described
287 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
288 * Specifically, the stack pointer points to a word containing
289 * ARGC. Following that in the stack is a null-terminated sequence
290 * of pointers to argument strings. Then comes a null-terminated
291 * sequence of pointers to environment strings. Finally, there is a
292 * sequence of "auxiliary vector" entries.
294 * The second argument points to a place to store the dynamic linker's
295 * exit procedure pointer and the third to a place to store the main
298 * The return value is the main program's entry point.
301 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
303 Elf_Auxinfo *aux_info[AT_COUNT];
311 Objlist_Entry *entry;
313 Obj_Entry **preload_tail;
315 RtldLockState lockstate;
320 * On entry, the dynamic linker itself has not been relocated yet.
321 * Be very careful not to reference any global data until after
322 * init_rtld has returned. It is OK to reference file-scope statics
323 * and string constants, and to call static and global functions.
326 /* Find the auxiliary vector on the stack. */
329 sp += argc + 1; /* Skip over arguments and NULL terminator */
331 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
333 aux = (Elf_Auxinfo *) sp;
335 /* Digest the auxiliary vector. */
336 for (i = 0; i < AT_COUNT; i++)
338 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
339 if (auxp->a_type < AT_COUNT)
340 aux_info[auxp->a_type] = auxp;
343 /* Initialize and relocate ourselves. */
344 assert(aux_info[AT_BASE] != NULL);
345 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
347 __progname = obj_rtld.path;
348 argv0 = argv[0] != NULL ? argv[0] : "(null)";
353 if (aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
354 i = aux_info[AT_CANARYLEN]->a_un.a_val;
355 if (i > sizeof(__stack_chk_guard))
356 i = sizeof(__stack_chk_guard);
357 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
362 len = sizeof(__stack_chk_guard);
363 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
364 len != sizeof(__stack_chk_guard)) {
365 /* If sysctl was unsuccessful, use the "terminator canary". */
366 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
367 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
368 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
369 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
373 trust = !issetugid();
375 ld_bind_now = getenv(LD_ "BIND_NOW");
377 * If the process is tainted, then we un-set the dangerous environment
378 * variables. The process will be marked as tainted until setuid(2)
379 * is called. If any child process calls setuid(2) we do not want any
380 * future processes to honor the potentially un-safe variables.
383 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
384 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
385 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
386 unsetenv(LD_ "LOADFLTR")) {
387 _rtld_error("environment corrupt; aborting");
391 ld_debug = getenv(LD_ "DEBUG");
392 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
393 libmap_override = getenv(LD_ "LIBMAP");
394 ld_library_path = getenv(LD_ "LIBRARY_PATH");
395 ld_preload = getenv(LD_ "PRELOAD");
396 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
397 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
398 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
399 (ld_library_path != NULL) || (ld_preload != NULL) ||
400 (ld_elf_hints_path != NULL) || ld_loadfltr;
401 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
402 ld_utrace = getenv(LD_ "UTRACE");
404 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
405 ld_elf_hints_path = _PATH_ELF_HINTS;
407 if (ld_debug != NULL && *ld_debug != '\0')
409 dbg("%s is initialized, base address = %p", __progname,
410 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
411 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
412 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
414 dbg("initializing thread locks");
418 * Load the main program, or process its program header if it is
421 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
422 int fd = aux_info[AT_EXECFD]->a_un.a_val;
423 dbg("loading main program");
424 obj_main = map_object(fd, argv0, NULL);
426 if (obj_main == NULL)
428 max_stack_flags = obj->stack_flags;
429 } else { /* Main program already loaded. */
430 const Elf_Phdr *phdr;
434 dbg("processing main program's program header");
435 assert(aux_info[AT_PHDR] != NULL);
436 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
437 assert(aux_info[AT_PHNUM] != NULL);
438 phnum = aux_info[AT_PHNUM]->a_un.a_val;
439 assert(aux_info[AT_PHENT] != NULL);
440 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
441 assert(aux_info[AT_ENTRY] != NULL);
442 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
443 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
447 if (aux_info[AT_EXECPATH] != 0) {
449 char buf[MAXPATHLEN];
451 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
452 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
453 if (kexecpath[0] == '/')
454 obj_main->path = kexecpath;
455 else if (getcwd(buf, sizeof(buf)) == NULL ||
456 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
457 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
458 obj_main->path = xstrdup(argv0);
460 obj_main->path = xstrdup(buf);
462 dbg("No AT_EXECPATH");
463 obj_main->path = xstrdup(argv0);
465 dbg("obj_main path %s", obj_main->path);
466 obj_main->mainprog = true;
468 if (aux_info[AT_STACKPROT] != NULL &&
469 aux_info[AT_STACKPROT]->a_un.a_val != 0)
470 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
473 * Get the actual dynamic linker pathname from the executable if
474 * possible. (It should always be possible.) That ensures that
475 * gdb will find the right dynamic linker even if a non-standard
478 if (obj_main->interp != NULL &&
479 strcmp(obj_main->interp, obj_rtld.path) != 0) {
481 obj_rtld.path = xstrdup(obj_main->interp);
482 __progname = obj_rtld.path;
485 digest_dynamic(obj_main, 0);
487 linkmap_add(obj_main);
488 linkmap_add(&obj_rtld);
490 /* Link the main program into the list of objects. */
491 *obj_tail = obj_main;
492 obj_tail = &obj_main->next;
496 /* Initialize a fake symbol for resolving undefined weak references. */
497 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
498 sym_zero.st_shndx = SHN_UNDEF;
499 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
502 libmap_disable = (bool)lm_init(libmap_override);
504 dbg("loading LD_PRELOAD libraries");
505 if (load_preload_objects() == -1)
507 preload_tail = obj_tail;
509 dbg("loading needed objects");
510 if (load_needed_objects(obj_main, 0) == -1)
513 /* Make a list of all objects loaded at startup. */
514 for (obj = obj_list; obj != NULL; obj = obj->next) {
515 objlist_push_tail(&list_main, obj);
519 dbg("checking for required versions");
520 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
523 if (ld_tracing) { /* We're done */
524 trace_loaded_objects(obj_main);
528 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
529 dump_relocations(obj_main);
534 * Processing tls relocations requires having the tls offsets
535 * initialized. Prepare offsets before starting initial
536 * relocation processing.
538 dbg("initializing initial thread local storage offsets");
539 STAILQ_FOREACH(entry, &list_main, link) {
541 * Allocate all the initial objects out of the static TLS
542 * block even if they didn't ask for it.
544 allocate_tls_offset(entry->obj);
547 if (relocate_objects(obj_main,
548 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, NULL) == -1)
551 dbg("doing copy relocations");
552 if (do_copy_relocations(obj_main) == -1)
555 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
556 dump_relocations(obj_main);
561 * Setup TLS for main thread. This must be done after the
562 * relocations are processed, since tls initialization section
563 * might be the subject for relocations.
565 dbg("initializing initial thread local storage");
566 allocate_initial_tls(obj_list);
568 dbg("initializing key program variables");
569 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
570 set_program_var("environ", env);
571 set_program_var("__elf_aux_vector", aux);
573 /* Make a list of init functions to call. */
574 objlist_init(&initlist);
575 initlist_add_objects(obj_list, preload_tail, &initlist);
577 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
579 map_stacks_exec(NULL);
581 dbg("resolving ifuncs");
582 if (resolve_objects_ifunc(obj_main,
583 ld_bind_now != NULL && *ld_bind_now != '\0', NULL) == -1)
586 if (!obj_main->crt_no_init) {
588 * Make sure we don't call the main program's init and fini
589 * functions for binaries linked with old crt1 which calls
592 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
593 obj_main->preinit_array = obj_main->init_array =
594 obj_main->fini_array = (Elf_Addr)NULL;
597 wlock_acquire(rtld_bind_lock, &lockstate);
598 if (obj_main->crt_no_init)
600 objlist_call_init(&initlist, &lockstate);
601 objlist_clear(&initlist);
602 dbg("loading filtees");
603 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
604 if (ld_loadfltr || obj->z_loadfltr)
605 load_filtees(obj, 0, &lockstate);
607 lock_release(rtld_bind_lock, &lockstate);
609 dbg("transferring control to program entry point = %p", obj_main->entry);
611 /* Return the exit procedure and the program entry point. */
612 *exit_proc = rtld_exit;
614 return (func_ptr_type) obj_main->entry;
618 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
623 ptr = (void *)make_function_pointer(def, obj);
624 target = ((Elf_Addr (*)(void))ptr)();
625 return ((void *)target);
629 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
633 const Obj_Entry *defobj;
636 RtldLockState lockstate;
638 rlock_acquire(rtld_bind_lock, &lockstate);
639 if (sigsetjmp(lockstate.env, 0) != 0)
640 lock_upgrade(rtld_bind_lock, &lockstate);
642 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
644 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
646 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
647 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
651 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
652 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
654 target = (Elf_Addr)(defobj->relocbase + def->st_value);
656 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
657 defobj->strtab + def->st_name, basename(obj->path),
658 (void *)target, basename(defobj->path));
661 * Write the new contents for the jmpslot. Note that depending on
662 * architecture, the value which we need to return back to the
663 * lazy binding trampoline may or may not be the target
664 * address. The value returned from reloc_jmpslot() is the value
665 * that the trampoline needs.
667 target = reloc_jmpslot(where, target, defobj, obj, rel);
668 lock_release(rtld_bind_lock, &lockstate);
673 * Error reporting function. Use it like printf. If formats the message
674 * into a buffer, and sets things up so that the next call to dlerror()
675 * will return the message.
678 _rtld_error(const char *fmt, ...)
680 static char buf[512];
684 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
690 * Return a dynamically-allocated copy of the current error message, if any.
695 return error_message == NULL ? NULL : xstrdup(error_message);
699 * Restore the current error message from a copy which was previously saved
700 * by errmsg_save(). The copy is freed.
703 errmsg_restore(char *saved_msg)
705 if (saved_msg == NULL)
706 error_message = NULL;
708 _rtld_error("%s", saved_msg);
714 basename(const char *name)
716 const char *p = strrchr(name, '/');
717 return p != NULL ? p + 1 : name;
720 static struct utsname uts;
723 origin_subst_one(char **res, const char *real, const char *kw, const char *subst,
733 subst_len = kw_len = 0;
737 if (subst_len == 0) {
738 subst_len = strlen(subst);
742 *res = xmalloc(PATH_MAX);
745 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) {
746 _rtld_error("Substitution of %s in %s cannot be performed",
748 if (may_free != NULL)
753 memcpy(res1, p, p1 - p);
755 memcpy(res1, subst, subst_len);
760 if (may_free != NULL)
763 *res = xstrdup(real);
767 if (may_free != NULL)
769 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) {
779 origin_subst(const char *real, const char *origin_path)
781 char *res1, *res2, *res3, *res4;
783 if (uts.sysname[0] == '\0') {
784 if (uname(&uts) != 0) {
785 _rtld_error("utsname failed: %d", errno);
789 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) ||
790 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) ||
791 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) ||
792 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3))
800 const char *msg = dlerror();
804 rtld_fdputstr(STDERR_FILENO, msg);
805 rtld_fdputchar(STDERR_FILENO, '\n');
810 * Process a shared object's DYNAMIC section, and save the important
811 * information in its Obj_Entry structure.
814 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
815 const Elf_Dyn **dyn_soname)
818 Needed_Entry **needed_tail = &obj->needed;
819 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
820 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
821 int plttype = DT_REL;
826 obj->bind_now = false;
827 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
828 switch (dynp->d_tag) {
831 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
835 obj->relsize = dynp->d_un.d_val;
839 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
843 obj->pltrel = (const Elf_Rel *)
844 (obj->relocbase + dynp->d_un.d_ptr);
848 obj->pltrelsize = dynp->d_un.d_val;
852 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
856 obj->relasize = dynp->d_un.d_val;
860 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
864 plttype = dynp->d_un.d_val;
865 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
869 obj->symtab = (const Elf_Sym *)
870 (obj->relocbase + dynp->d_un.d_ptr);
874 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
878 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
882 obj->strsize = dynp->d_un.d_val;
886 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
891 obj->verneednum = dynp->d_un.d_val;
895 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
900 obj->verdefnum = dynp->d_un.d_val;
904 obj->versyms = (const Elf_Versym *)(obj->relocbase +
910 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
911 (obj->relocbase + dynp->d_un.d_ptr);
912 obj->nbuckets = hashtab[0];
913 obj->nchains = hashtab[1];
914 obj->buckets = hashtab + 2;
915 obj->chains = obj->buckets + obj->nbuckets;
921 Needed_Entry *nep = NEW(Needed_Entry);
922 nep->name = dynp->d_un.d_val;
927 needed_tail = &nep->next;
933 Needed_Entry *nep = NEW(Needed_Entry);
934 nep->name = dynp->d_un.d_val;
938 *needed_filtees_tail = nep;
939 needed_filtees_tail = &nep->next;
945 Needed_Entry *nep = NEW(Needed_Entry);
946 nep->name = dynp->d_un.d_val;
950 *needed_aux_filtees_tail = nep;
951 needed_aux_filtees_tail = &nep->next;
956 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
964 obj->symbolic = true;
968 case DT_RUNPATH: /* XXX: process separately */
970 * We have to wait until later to process this, because we
971 * might not have gotten the address of the string table yet.
981 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
984 case DT_PREINIT_ARRAY:
985 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
988 case DT_PREINIT_ARRAYSZ:
989 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
993 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
996 case DT_INIT_ARRAYSZ:
997 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1001 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1005 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1008 case DT_FINI_ARRAYSZ:
1009 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1013 * Don't process DT_DEBUG on MIPS as the dynamic section
1014 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1019 /* XXX - not implemented yet */
1021 dbg("Filling in DT_DEBUG entry");
1022 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1027 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1028 obj->z_origin = true;
1029 if (dynp->d_un.d_val & DF_SYMBOLIC)
1030 obj->symbolic = true;
1031 if (dynp->d_un.d_val & DF_TEXTREL)
1032 obj->textrel = true;
1033 if (dynp->d_un.d_val & DF_BIND_NOW)
1034 obj->bind_now = true;
1035 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1039 case DT_MIPS_LOCAL_GOTNO:
1040 obj->local_gotno = dynp->d_un.d_val;
1043 case DT_MIPS_SYMTABNO:
1044 obj->symtabno = dynp->d_un.d_val;
1047 case DT_MIPS_GOTSYM:
1048 obj->gotsym = dynp->d_un.d_val;
1051 case DT_MIPS_RLD_MAP:
1054 dbg("Filling in DT_DEBUG entry");
1055 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1061 if (dynp->d_un.d_val & DF_1_NOOPEN)
1062 obj->z_noopen = true;
1063 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1064 obj->z_origin = true;
1065 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1067 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1068 obj->bind_now = true;
1069 if (dynp->d_un.d_val & DF_1_NODELETE)
1070 obj->z_nodelete = true;
1071 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1072 obj->z_loadfltr = true;
1077 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1084 obj->traced = false;
1086 if (plttype == DT_RELA) {
1087 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1089 obj->pltrelasize = obj->pltrelsize;
1090 obj->pltrelsize = 0;
1095 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1096 const Elf_Dyn *dyn_soname)
1099 if (obj->z_origin && obj->origin_path == NULL) {
1100 obj->origin_path = xmalloc(PATH_MAX);
1101 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1105 if (dyn_rpath != NULL) {
1106 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1108 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1111 if (dyn_soname != NULL)
1112 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1116 digest_dynamic(Obj_Entry *obj, int early)
1118 const Elf_Dyn *dyn_rpath;
1119 const Elf_Dyn *dyn_soname;
1121 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname);
1122 digest_dynamic2(obj, dyn_rpath, dyn_soname);
1126 * Process a shared object's program header. This is used only for the
1127 * main program, when the kernel has already loaded the main program
1128 * into memory before calling the dynamic linker. It creates and
1129 * returns an Obj_Entry structure.
1132 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1135 const Elf_Phdr *phlimit = phdr + phnum;
1137 Elf_Addr note_start, note_end;
1141 for (ph = phdr; ph < phlimit; ph++) {
1142 if (ph->p_type != PT_PHDR)
1146 obj->phsize = ph->p_memsz;
1147 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1151 obj->stack_flags = PF_X | PF_R | PF_W;
1153 for (ph = phdr; ph < phlimit; ph++) {
1154 switch (ph->p_type) {
1157 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1161 if (nsegs == 0) { /* First load segment */
1162 obj->vaddrbase = trunc_page(ph->p_vaddr);
1163 obj->mapbase = obj->vaddrbase + obj->relocbase;
1164 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1166 } else { /* Last load segment */
1167 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1174 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1179 obj->tlssize = ph->p_memsz;
1180 obj->tlsalign = ph->p_align;
1181 obj->tlsinitsize = ph->p_filesz;
1182 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1186 obj->stack_flags = ph->p_flags;
1190 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1191 obj->relro_size = round_page(ph->p_memsz);
1195 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1196 note_end = note_start + ph->p_filesz;
1197 digest_notes(obj, note_start, note_end);
1202 _rtld_error("%s: too few PT_LOAD segments", path);
1211 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1213 const Elf_Note *note;
1214 const char *note_name;
1217 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1218 note = (const Elf_Note *)((const char *)(note + 1) +
1219 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1220 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1221 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1222 note->n_descsz != sizeof(int32_t))
1224 if (note->n_type != ABI_NOTETYPE &&
1225 note->n_type != CRT_NOINIT_NOTETYPE)
1227 note_name = (const char *)(note + 1);
1228 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1229 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1231 switch (note->n_type) {
1233 /* FreeBSD osrel note */
1234 p = (uintptr_t)(note + 1);
1235 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1236 obj->osrel = *(const int32_t *)(p);
1237 dbg("note osrel %d", obj->osrel);
1239 case CRT_NOINIT_NOTETYPE:
1240 /* FreeBSD 'crt does not call init' note */
1241 obj->crt_no_init = true;
1242 dbg("note crt_no_init");
1249 dlcheck(void *handle)
1253 for (obj = obj_list; obj != NULL; obj = obj->next)
1254 if (obj == (Obj_Entry *) handle)
1257 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1258 _rtld_error("Invalid shared object handle %p", handle);
1265 * If the given object is already in the donelist, return true. Otherwise
1266 * add the object to the list and return false.
1269 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1273 for (i = 0; i < dlp->num_used; i++)
1274 if (dlp->objs[i] == obj)
1277 * Our donelist allocation should always be sufficient. But if
1278 * our threads locking isn't working properly, more shared objects
1279 * could have been loaded since we allocated the list. That should
1280 * never happen, but we'll handle it properly just in case it does.
1282 if (dlp->num_used < dlp->num_alloc)
1283 dlp->objs[dlp->num_used++] = obj;
1288 * Hash function for symbol table lookup. Don't even think about changing
1289 * this. It is specified by the System V ABI.
1292 elf_hash(const char *name)
1294 const unsigned char *p = (const unsigned char *) name;
1295 unsigned long h = 0;
1298 while (*p != '\0') {
1299 h = (h << 4) + *p++;
1300 if ((g = h & 0xf0000000) != 0)
1308 * Find the library with the given name, and return its full pathname.
1309 * The returned string is dynamically allocated. Generates an error
1310 * message and returns NULL if the library cannot be found.
1312 * If the second argument is non-NULL, then it refers to an already-
1313 * loaded shared object, whose library search path will be searched.
1315 * The search order is:
1317 * rpath in the referencing file
1322 find_library(const char *xname, const Obj_Entry *refobj)
1327 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1328 if (xname[0] != '/' && !trust) {
1329 _rtld_error("Absolute pathname required for shared object \"%s\"",
1333 if (refobj != NULL && refobj->z_origin)
1334 return origin_subst(xname, refobj->origin_path);
1336 return xstrdup(xname);
1339 if (libmap_disable || (refobj == NULL) ||
1340 (name = lm_find(refobj->path, xname)) == NULL)
1341 name = (char *)xname;
1343 dbg(" Searching for \"%s\"", name);
1345 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1347 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1348 (pathname = search_library_path(name, gethints())) != NULL ||
1349 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1352 if(refobj != NULL && refobj->path != NULL) {
1353 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1354 name, basename(refobj->path));
1356 _rtld_error("Shared object \"%s\" not found", name);
1362 * Given a symbol number in a referencing object, find the corresponding
1363 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1364 * no definition was found. Returns a pointer to the Obj_Entry of the
1365 * defining object via the reference parameter DEFOBJ_OUT.
1368 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1369 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1370 RtldLockState *lockstate)
1374 const Obj_Entry *defobj;
1380 * If we have already found this symbol, get the information from
1383 if (symnum >= refobj->nchains)
1384 return NULL; /* Bad object */
1385 if (cache != NULL && cache[symnum].sym != NULL) {
1386 *defobj_out = cache[symnum].obj;
1387 return cache[symnum].sym;
1390 ref = refobj->symtab + symnum;
1391 name = refobj->strtab + ref->st_name;
1396 * We don't have to do a full scale lookup if the symbol is local.
1397 * We know it will bind to the instance in this load module; to
1398 * which we already have a pointer (ie ref). By not doing a lookup,
1399 * we not only improve performance, but it also avoids unresolvable
1400 * symbols when local symbols are not in the hash table. This has
1401 * been seen with the ia64 toolchain.
1403 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1404 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1405 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1408 symlook_init(&req, name);
1410 req.ventry = fetch_ventry(refobj, symnum);
1411 req.lockstate = lockstate;
1412 res = symlook_default(&req, refobj);
1415 defobj = req.defobj_out;
1423 * If we found no definition and the reference is weak, treat the
1424 * symbol as having the value zero.
1426 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1432 *defobj_out = defobj;
1433 /* Record the information in the cache to avoid subsequent lookups. */
1434 if (cache != NULL) {
1435 cache[symnum].sym = def;
1436 cache[symnum].obj = defobj;
1439 if (refobj != &obj_rtld)
1440 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1446 * Return the search path from the ldconfig hints file, reading it if
1447 * necessary. Returns NULL if there are problems with the hints file,
1448 * or if the search path there is empty.
1455 if (hints == NULL) {
1457 struct elfhints_hdr hdr;
1460 /* Keep from trying again in case the hints file is bad. */
1463 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1465 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1466 hdr.magic != ELFHINTS_MAGIC ||
1471 p = xmalloc(hdr.dirlistlen + 1);
1472 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1473 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1481 return hints[0] != '\0' ? hints : NULL;
1485 init_dag(Obj_Entry *root)
1487 const Needed_Entry *needed;
1488 const Objlist_Entry *elm;
1491 if (root->dag_inited)
1493 donelist_init(&donelist);
1495 /* Root object belongs to own DAG. */
1496 objlist_push_tail(&root->dldags, root);
1497 objlist_push_tail(&root->dagmembers, root);
1498 donelist_check(&donelist, root);
1501 * Add dependencies of root object to DAG in breadth order
1502 * by exploiting the fact that each new object get added
1503 * to the tail of the dagmembers list.
1505 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1506 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1507 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1509 objlist_push_tail(&needed->obj->dldags, root);
1510 objlist_push_tail(&root->dagmembers, needed->obj);
1513 root->dag_inited = true;
1517 * Initialize the dynamic linker. The argument is the address at which
1518 * the dynamic linker has been mapped into memory. The primary task of
1519 * this function is to relocate the dynamic linker.
1522 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1524 Obj_Entry objtmp; /* Temporary rtld object */
1525 const Elf_Dyn *dyn_rpath;
1526 const Elf_Dyn *dyn_soname;
1529 * Conjure up an Obj_Entry structure for the dynamic linker.
1531 * The "path" member can't be initialized yet because string constants
1532 * cannot yet be accessed. Below we will set it correctly.
1534 memset(&objtmp, 0, sizeof(objtmp));
1537 objtmp.mapbase = mapbase;
1539 objtmp.relocbase = mapbase;
1541 if (RTLD_IS_DYNAMIC()) {
1542 objtmp.dynamic = rtld_dynamic(&objtmp);
1543 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname);
1544 assert(objtmp.needed == NULL);
1545 #if !defined(__mips__)
1546 /* MIPS has a bogus DT_TEXTREL. */
1547 assert(!objtmp.textrel);
1551 * Temporarily put the dynamic linker entry into the object list, so
1552 * that symbols can be found.
1555 relocate_objects(&objtmp, true, &objtmp, NULL);
1558 /* Initialize the object list. */
1559 obj_tail = &obj_list;
1561 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1562 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1564 if (aux_info[AT_PAGESZ] != NULL)
1565 pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
1566 if (aux_info[AT_OSRELDATE] != NULL)
1567 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1569 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname);
1571 /* Replace the path with a dynamically allocated copy. */
1572 obj_rtld.path = xstrdup(PATH_RTLD);
1574 r_debug.r_brk = r_debug_state;
1575 r_debug.r_state = RT_CONSISTENT;
1579 * Add the init functions from a needed object list (and its recursive
1580 * needed objects) to "list". This is not used directly; it is a helper
1581 * function for initlist_add_objects(). The write lock must be held
1582 * when this function is called.
1585 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1587 /* Recursively process the successor needed objects. */
1588 if (needed->next != NULL)
1589 initlist_add_neededs(needed->next, list);
1591 /* Process the current needed object. */
1592 if (needed->obj != NULL)
1593 initlist_add_objects(needed->obj, &needed->obj->next, list);
1597 * Scan all of the DAGs rooted in the range of objects from "obj" to
1598 * "tail" and add their init functions to "list". This recurses over
1599 * the DAGs and ensure the proper init ordering such that each object's
1600 * needed libraries are initialized before the object itself. At the
1601 * same time, this function adds the objects to the global finalization
1602 * list "list_fini" in the opposite order. The write lock must be
1603 * held when this function is called.
1606 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1608 if (obj->init_scanned || obj->init_done)
1610 obj->init_scanned = true;
1612 /* Recursively process the successor objects. */
1613 if (&obj->next != tail)
1614 initlist_add_objects(obj->next, tail, list);
1616 /* Recursively process the needed objects. */
1617 if (obj->needed != NULL)
1618 initlist_add_neededs(obj->needed, list);
1620 /* Add the object to the init list. */
1621 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1622 obj->init_array != (Elf_Addr)NULL)
1623 objlist_push_tail(list, obj);
1625 /* Add the object to the global fini list in the reverse order. */
1626 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1627 && !obj->on_fini_list) {
1628 objlist_push_head(&list_fini, obj);
1629 obj->on_fini_list = true;
1634 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1638 free_needed_filtees(Needed_Entry *n)
1640 Needed_Entry *needed, *needed1;
1642 for (needed = n; needed != NULL; needed = needed->next) {
1643 if (needed->obj != NULL) {
1644 dlclose(needed->obj);
1648 for (needed = n; needed != NULL; needed = needed1) {
1649 needed1 = needed->next;
1655 unload_filtees(Obj_Entry *obj)
1658 free_needed_filtees(obj->needed_filtees);
1659 obj->needed_filtees = NULL;
1660 free_needed_filtees(obj->needed_aux_filtees);
1661 obj->needed_aux_filtees = NULL;
1662 obj->filtees_loaded = false;
1666 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags)
1669 for (; needed != NULL; needed = needed->next) {
1670 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1671 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1677 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1680 lock_restart_for_upgrade(lockstate);
1681 if (!obj->filtees_loaded) {
1682 load_filtee1(obj, obj->needed_filtees, flags);
1683 load_filtee1(obj, obj->needed_aux_filtees, flags);
1684 obj->filtees_loaded = true;
1689 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1693 for (; needed != NULL; needed = needed->next) {
1694 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
1695 flags & ~RTLD_LO_NOLOAD);
1696 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1698 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
1699 dbg("obj %s nodelete", obj1->path);
1702 obj1->ref_nodel = true;
1709 * Given a shared object, traverse its list of needed objects, and load
1710 * each of them. Returns 0 on success. Generates an error message and
1711 * returns -1 on failure.
1714 load_needed_objects(Obj_Entry *first, int flags)
1718 for (obj = first; obj != NULL; obj = obj->next) {
1719 if (process_needed(obj, obj->needed, flags) == -1)
1726 load_preload_objects(void)
1728 char *p = ld_preload;
1729 static const char delim[] = " \t:;";
1734 p += strspn(p, delim);
1735 while (*p != '\0') {
1736 size_t len = strcspn(p, delim);
1741 if (load_object(p, -1, NULL, 0) == NULL)
1742 return -1; /* XXX - cleanup */
1745 p += strspn(p, delim);
1747 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
1752 printable_path(const char *path)
1755 return (path == NULL ? "<unknown>" : path);
1759 * Load a shared object into memory, if it is not already loaded. The
1760 * object may be specified by name or by user-supplied file descriptor
1761 * fd_u. In the later case, the fd_u descriptor is not closed, but its
1764 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1768 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
1776 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
1777 if (object_match_name(obj, name))
1781 path = find_library(name, refobj);
1788 * If we didn't find a match by pathname, or the name is not
1789 * supplied, open the file and check again by device and inode.
1790 * This avoids false mismatches caused by multiple links or ".."
1793 * To avoid a race, we open the file and use fstat() rather than
1798 if ((fd = open(path, O_RDONLY)) == -1) {
1799 _rtld_error("Cannot open \"%s\"", path);
1806 _rtld_error("Cannot dup fd");
1811 if (fstat(fd, &sb) == -1) {
1812 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
1817 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1818 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
1820 if (obj != NULL && name != NULL) {
1821 object_add_name(obj, name);
1826 if (flags & RTLD_LO_NOLOAD) {
1832 /* First use of this object, so we must map it in */
1833 obj = do_load_object(fd, name, path, &sb, flags);
1842 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
1849 * but first, make sure that environment variables haven't been
1850 * used to circumvent the noexec flag on a filesystem.
1852 if (dangerous_ld_env) {
1853 if (fstatfs(fd, &fs) != 0) {
1854 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
1857 if (fs.f_flags & MNT_NOEXEC) {
1858 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
1862 dbg("loading \"%s\"", printable_path(path));
1863 obj = map_object(fd, printable_path(path), sbp);
1868 * If DT_SONAME is present in the object, digest_dynamic2 already
1869 * added it to the object names.
1872 object_add_name(obj, name);
1874 digest_dynamic(obj, 0);
1875 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
1877 dbg("refusing to load non-loadable \"%s\"", obj->path);
1878 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
1879 munmap(obj->mapbase, obj->mapsize);
1885 obj_tail = &obj->next;
1888 linkmap_add(obj); /* for GDB & dlinfo() */
1889 max_stack_flags |= obj->stack_flags;
1891 dbg(" %p .. %p: %s", obj->mapbase,
1892 obj->mapbase + obj->mapsize - 1, obj->path);
1894 dbg(" WARNING: %s has impure text", obj->path);
1895 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
1902 obj_from_addr(const void *addr)
1906 for (obj = obj_list; obj != NULL; obj = obj->next) {
1907 if (addr < (void *) obj->mapbase)
1909 if (addr < (void *) (obj->mapbase + obj->mapsize))
1918 Elf_Addr *preinit_addr;
1921 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
1922 if (preinit_addr == NULL)
1925 for (index = 0; index < obj_main->preinit_array_num; index++) {
1926 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
1927 dbg("calling preinit function for %s at %p", obj_main->path,
1928 (void *)preinit_addr[index]);
1929 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
1930 0, 0, obj_main->path);
1931 call_init_pointer(obj_main, preinit_addr[index]);
1937 * Call the finalization functions for each of the objects in "list"
1938 * belonging to the DAG of "root" and referenced once. If NULL "root"
1939 * is specified, every finalization function will be called regardless
1940 * of the reference count and the list elements won't be freed. All of
1941 * the objects are expected to have non-NULL fini functions.
1944 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
1948 Elf_Addr *fini_addr;
1951 assert(root == NULL || root->refcount == 1);
1954 * Preserve the current error message since a fini function might
1955 * call into the dynamic linker and overwrite it.
1957 saved_msg = errmsg_save();
1959 STAILQ_FOREACH(elm, list, link) {
1960 if (root != NULL && (elm->obj->refcount != 1 ||
1961 objlist_find(&root->dagmembers, elm->obj) == NULL))
1963 /* Remove object from fini list to prevent recursive invocation. */
1964 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1966 * XXX: If a dlopen() call references an object while the
1967 * fini function is in progress, we might end up trying to
1968 * unload the referenced object in dlclose() or the object
1969 * won't be unloaded although its fini function has been
1972 lock_release(rtld_bind_lock, lockstate);
1975 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
1976 * When this happens, DT_FINI_ARRAY is processed first.
1978 fini_addr = (Elf_Addr *)elm->obj->fini_array;
1979 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
1980 for (index = elm->obj->fini_array_num - 1; index >= 0;
1982 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
1983 dbg("calling fini function for %s at %p",
1984 elm->obj->path, (void *)fini_addr[index]);
1985 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
1986 (void *)fini_addr[index], 0, 0, elm->obj->path);
1987 call_initfini_pointer(elm->obj, fini_addr[index]);
1991 if (elm->obj->fini != (Elf_Addr)NULL) {
1992 dbg("calling fini function for %s at %p", elm->obj->path,
1993 (void *)elm->obj->fini);
1994 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
1995 0, 0, elm->obj->path);
1996 call_initfini_pointer(elm->obj, elm->obj->fini);
1998 wlock_acquire(rtld_bind_lock, lockstate);
1999 /* No need to free anything if process is going down. */
2003 * We must restart the list traversal after every fini call
2004 * because a dlclose() call from the fini function or from
2005 * another thread might have modified the reference counts.
2009 } while (elm != NULL);
2010 errmsg_restore(saved_msg);
2014 * Call the initialization functions for each of the objects in
2015 * "list". All of the objects are expected to have non-NULL init
2019 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2024 Elf_Addr *init_addr;
2028 * Clean init_scanned flag so that objects can be rechecked and
2029 * possibly initialized earlier if any of vectors called below
2030 * cause the change by using dlopen.
2032 for (obj = obj_list; obj != NULL; obj = obj->next)
2033 obj->init_scanned = false;
2036 * Preserve the current error message since an init function might
2037 * call into the dynamic linker and overwrite it.
2039 saved_msg = errmsg_save();
2040 STAILQ_FOREACH(elm, list, link) {
2041 if (elm->obj->init_done) /* Initialized early. */
2044 * Race: other thread might try to use this object before current
2045 * one completes the initilization. Not much can be done here
2046 * without better locking.
2048 elm->obj->init_done = true;
2049 lock_release(rtld_bind_lock, lockstate);
2052 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2053 * When this happens, DT_INIT is processed first.
2055 if (elm->obj->init != (Elf_Addr)NULL) {
2056 dbg("calling init function for %s at %p", elm->obj->path,
2057 (void *)elm->obj->init);
2058 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2059 0, 0, elm->obj->path);
2060 call_initfini_pointer(elm->obj, elm->obj->init);
2062 init_addr = (Elf_Addr *)elm->obj->init_array;
2063 if (init_addr != NULL) {
2064 for (index = 0; index < elm->obj->init_array_num; index++) {
2065 if (init_addr[index] != 0 && init_addr[index] != 1) {
2066 dbg("calling init function for %s at %p", elm->obj->path,
2067 (void *)init_addr[index]);
2068 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2069 (void *)init_addr[index], 0, 0, elm->obj->path);
2070 call_init_pointer(elm->obj, init_addr[index]);
2074 wlock_acquire(rtld_bind_lock, lockstate);
2076 errmsg_restore(saved_msg);
2080 objlist_clear(Objlist *list)
2084 while (!STAILQ_EMPTY(list)) {
2085 elm = STAILQ_FIRST(list);
2086 STAILQ_REMOVE_HEAD(list, link);
2091 static Objlist_Entry *
2092 objlist_find(Objlist *list, const Obj_Entry *obj)
2096 STAILQ_FOREACH(elm, list, link)
2097 if (elm->obj == obj)
2103 objlist_init(Objlist *list)
2109 objlist_push_head(Objlist *list, Obj_Entry *obj)
2113 elm = NEW(Objlist_Entry);
2115 STAILQ_INSERT_HEAD(list, elm, link);
2119 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2123 elm = NEW(Objlist_Entry);
2125 STAILQ_INSERT_TAIL(list, elm, link);
2129 objlist_remove(Objlist *list, Obj_Entry *obj)
2133 if ((elm = objlist_find(list, obj)) != NULL) {
2134 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2140 * Relocate newly-loaded shared objects. The argument is a pointer to
2141 * the Obj_Entry for the first such object. All objects from the first
2142 * to the end of the list of objects are relocated. Returns 0 on success,
2146 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2147 RtldLockState *lockstate)
2151 for (obj = first; obj != NULL; obj = obj->next) {
2153 dbg("relocating \"%s\"", obj->path);
2154 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
2155 obj->symtab == NULL || obj->strtab == NULL) {
2156 _rtld_error("%s: Shared object has no run-time symbol table",
2162 /* There are relocations to the write-protected text segment. */
2163 if (mprotect(obj->mapbase, obj->textsize,
2164 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2165 _rtld_error("%s: Cannot write-enable text segment: %s",
2166 obj->path, rtld_strerror(errno));
2171 /* Process the non-PLT relocations. */
2172 if (reloc_non_plt(obj, rtldobj, lockstate))
2175 if (obj->textrel) { /* Re-protected the text segment. */
2176 if (mprotect(obj->mapbase, obj->textsize,
2177 PROT_READ|PROT_EXEC) == -1) {
2178 _rtld_error("%s: Cannot write-protect text segment: %s",
2179 obj->path, rtld_strerror(errno));
2185 /* Set the special PLT or GOT entries. */
2188 /* Process the PLT relocations. */
2189 if (reloc_plt(obj) == -1)
2191 /* Relocate the jump slots if we are doing immediate binding. */
2192 if (obj->bind_now || bind_now)
2193 if (reloc_jmpslots(obj, lockstate) == -1)
2196 if (obj->relro_size > 0) {
2197 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
2198 _rtld_error("%s: Cannot enforce relro protection: %s",
2199 obj->path, rtld_strerror(errno));
2205 * Set up the magic number and version in the Obj_Entry. These
2206 * were checked in the crt1.o from the original ElfKit, so we
2207 * set them for backward compatibility.
2209 obj->magic = RTLD_MAGIC;
2210 obj->version = RTLD_VERSION;
2217 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2218 * referencing STT_GNU_IFUNC symbols is postponed till the other
2219 * relocations are done. The indirect functions specified as
2220 * ifunc are allowed to call other symbols, so we need to have
2221 * objects relocated before asking for resolution from indirects.
2223 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2224 * instead of the usual lazy handling of PLT slots. It is
2225 * consistent with how GNU does it.
2228 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, RtldLockState *lockstate)
2230 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2232 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2233 reloc_gnu_ifunc(obj, lockstate) == -1)
2239 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, RtldLockState *lockstate)
2243 for (obj = first; obj != NULL; obj = obj->next) {
2244 if (resolve_object_ifunc(obj, bind_now, lockstate) == -1)
2251 initlist_objects_ifunc(Objlist *list, bool bind_now, RtldLockState *lockstate)
2255 STAILQ_FOREACH(elm, list, link) {
2256 if (resolve_object_ifunc(elm->obj, bind_now, lockstate) == -1)
2263 * Cleanup procedure. It will be called (by the atexit mechanism) just
2264 * before the process exits.
2269 RtldLockState lockstate;
2271 wlock_acquire(rtld_bind_lock, &lockstate);
2273 objlist_call_fini(&list_fini, NULL, &lockstate);
2274 /* No need to remove the items from the list, since we are exiting. */
2275 if (!libmap_disable)
2277 lock_release(rtld_bind_lock, &lockstate);
2281 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2289 path += strspn(path, ":;");
2290 while (*path != '\0') {
2294 len = strcspn(path, ":;");
2296 trans = lm_findn(NULL, path, len);
2298 res = callback(trans, strlen(trans), arg);
2301 res = callback(path, len, arg);
2307 path += strspn(path, ":;");
2313 struct try_library_args {
2321 try_library_path(const char *dir, size_t dirlen, void *param)
2323 struct try_library_args *arg;
2326 if (*dir == '/' || trust) {
2329 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2332 pathname = arg->buffer;
2333 strncpy(pathname, dir, dirlen);
2334 pathname[dirlen] = '/';
2335 strcpy(pathname + dirlen + 1, arg->name);
2337 dbg(" Trying \"%s\"", pathname);
2338 if (access(pathname, F_OK) == 0) { /* We found it */
2339 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2340 strcpy(pathname, arg->buffer);
2348 search_library_path(const char *name, const char *path)
2351 struct try_library_args arg;
2357 arg.namelen = strlen(name);
2358 arg.buffer = xmalloc(PATH_MAX);
2359 arg.buflen = PATH_MAX;
2361 p = path_enumerate(path, try_library_path, &arg);
2369 dlclose(void *handle)
2372 RtldLockState lockstate;
2374 wlock_acquire(rtld_bind_lock, &lockstate);
2375 root = dlcheck(handle);
2377 lock_release(rtld_bind_lock, &lockstate);
2380 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2383 /* Unreference the object and its dependencies. */
2384 root->dl_refcount--;
2386 if (root->refcount == 1) {
2388 * The object will be no longer referenced, so we must unload it.
2389 * First, call the fini functions.
2391 objlist_call_fini(&list_fini, root, &lockstate);
2395 /* Finish cleaning up the newly-unreferenced objects. */
2396 GDB_STATE(RT_DELETE,&root->linkmap);
2397 unload_object(root);
2398 GDB_STATE(RT_CONSISTENT,NULL);
2402 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2403 lock_release(rtld_bind_lock, &lockstate);
2410 char *msg = error_message;
2411 error_message = NULL;
2416 * This function is deprecated and has no effect.
2419 dllockinit(void *context,
2420 void *(*lock_create)(void *context),
2421 void (*rlock_acquire)(void *lock),
2422 void (*wlock_acquire)(void *lock),
2423 void (*lock_release)(void *lock),
2424 void (*lock_destroy)(void *lock),
2425 void (*context_destroy)(void *context))
2427 static void *cur_context;
2428 static void (*cur_context_destroy)(void *);
2430 /* Just destroy the context from the previous call, if necessary. */
2431 if (cur_context_destroy != NULL)
2432 cur_context_destroy(cur_context);
2433 cur_context = context;
2434 cur_context_destroy = context_destroy;
2438 dlopen(const char *name, int mode)
2441 return (rtld_dlopen(name, -1, mode));
2445 fdlopen(int fd, int mode)
2448 return (rtld_dlopen(NULL, fd, mode));
2452 rtld_dlopen(const char *name, int fd, int mode)
2454 RtldLockState lockstate;
2457 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2458 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2459 if (ld_tracing != NULL) {
2460 rlock_acquire(rtld_bind_lock, &lockstate);
2461 if (sigsetjmp(lockstate.env, 0) != 0)
2462 lock_upgrade(rtld_bind_lock, &lockstate);
2463 environ = (char **)*get_program_var_addr("environ", &lockstate);
2464 lock_release(rtld_bind_lock, &lockstate);
2466 lo_flags = RTLD_LO_DLOPEN;
2467 if (mode & RTLD_NODELETE)
2468 lo_flags |= RTLD_LO_NODELETE;
2469 if (mode & RTLD_NOLOAD)
2470 lo_flags |= RTLD_LO_NOLOAD;
2471 if (ld_tracing != NULL)
2472 lo_flags |= RTLD_LO_TRACE;
2474 return (dlopen_object(name, fd, obj_main, lo_flags,
2475 mode & (RTLD_MODEMASK | RTLD_GLOBAL)));
2479 dlopen_cleanup(Obj_Entry *obj)
2484 if (obj->refcount == 0)
2489 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2492 Obj_Entry **old_obj_tail;
2495 RtldLockState lockstate;
2498 objlist_init(&initlist);
2500 wlock_acquire(rtld_bind_lock, &lockstate);
2501 GDB_STATE(RT_ADD,NULL);
2503 old_obj_tail = obj_tail;
2505 if (name == NULL && fd == -1) {
2509 obj = load_object(name, fd, refobj, lo_flags);
2514 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2515 objlist_push_tail(&list_global, obj);
2516 if (*old_obj_tail != NULL) { /* We loaded something new. */
2517 assert(*old_obj_tail == obj);
2518 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN);
2522 result = rtld_verify_versions(&obj->dagmembers);
2523 if (result != -1 && ld_tracing)
2525 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK)
2526 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) {
2527 dlopen_cleanup(obj);
2530 /* Make list of init functions to call. */
2531 initlist_add_objects(obj, &obj->next, &initlist);
2536 * Bump the reference counts for objects on this DAG. If
2537 * this is the first dlopen() call for the object that was
2538 * already loaded as a dependency, initialize the dag
2544 if ((lo_flags & RTLD_LO_TRACE) != 0)
2547 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2548 obj->z_nodelete) && !obj->ref_nodel) {
2549 dbg("obj %s nodelete", obj->path);
2551 obj->z_nodelete = obj->ref_nodel = true;
2555 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2557 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2559 map_stacks_exec(&lockstate);
2561 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2562 &lockstate) == -1) {
2563 objlist_clear(&initlist);
2564 dlopen_cleanup(obj);
2565 lock_release(rtld_bind_lock, &lockstate);
2569 /* Call the init functions. */
2570 objlist_call_init(&initlist, &lockstate);
2571 objlist_clear(&initlist);
2572 lock_release(rtld_bind_lock, &lockstate);
2575 trace_loaded_objects(obj);
2576 lock_release(rtld_bind_lock, &lockstate);
2581 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2585 const Obj_Entry *obj, *defobj;
2588 RtldLockState lockstate;
2593 symlook_init(&req, name);
2595 req.flags = flags | SYMLOOK_IN_PLT;
2596 req.lockstate = &lockstate;
2598 rlock_acquire(rtld_bind_lock, &lockstate);
2599 if (sigsetjmp(lockstate.env, 0) != 0)
2600 lock_upgrade(rtld_bind_lock, &lockstate);
2601 if (handle == NULL || handle == RTLD_NEXT ||
2602 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2604 if ((obj = obj_from_addr(retaddr)) == NULL) {
2605 _rtld_error("Cannot determine caller's shared object");
2606 lock_release(rtld_bind_lock, &lockstate);
2609 if (handle == NULL) { /* Just the caller's shared object. */
2610 res = symlook_obj(&req, obj);
2613 defobj = req.defobj_out;
2615 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2616 handle == RTLD_SELF) { /* ... caller included */
2617 if (handle == RTLD_NEXT)
2619 for (; obj != NULL; obj = obj->next) {
2620 res = symlook_obj(&req, obj);
2623 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2625 defobj = req.defobj_out;
2626 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2632 * Search the dynamic linker itself, and possibly resolve the
2633 * symbol from there. This is how the application links to
2634 * dynamic linker services such as dlopen.
2636 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2637 res = symlook_obj(&req, &obj_rtld);
2640 defobj = req.defobj_out;
2644 assert(handle == RTLD_DEFAULT);
2645 res = symlook_default(&req, obj);
2647 defobj = req.defobj_out;
2652 if ((obj = dlcheck(handle)) == NULL) {
2653 lock_release(rtld_bind_lock, &lockstate);
2657 donelist_init(&donelist);
2658 if (obj->mainprog) {
2659 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
2660 res = symlook_global(&req, &donelist);
2663 defobj = req.defobj_out;
2666 * Search the dynamic linker itself, and possibly resolve the
2667 * symbol from there. This is how the application links to
2668 * dynamic linker services such as dlopen.
2670 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2671 res = symlook_obj(&req, &obj_rtld);
2674 defobj = req.defobj_out;
2679 /* Search the whole DAG rooted at the given object. */
2680 res = symlook_list(&req, &obj->dagmembers, &donelist);
2683 defobj = req.defobj_out;
2689 lock_release(rtld_bind_lock, &lockstate);
2692 * The value required by the caller is derived from the value
2693 * of the symbol. For the ia64 architecture, we need to
2694 * construct a function descriptor which the caller can use to
2695 * call the function with the right 'gp' value. For other
2696 * architectures and for non-functions, the value is simply
2697 * the relocated value of the symbol.
2699 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
2700 return (make_function_pointer(def, defobj));
2701 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
2702 return (rtld_resolve_ifunc(defobj, def));
2704 return (defobj->relocbase + def->st_value);
2707 _rtld_error("Undefined symbol \"%s\"", name);
2708 lock_release(rtld_bind_lock, &lockstate);
2713 dlsym(void *handle, const char *name)
2715 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2720 dlfunc(void *handle, const char *name)
2727 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
2733 dlvsym(void *handle, const char *name, const char *version)
2737 ventry.name = version;
2739 ventry.hash = elf_hash(version);
2741 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2746 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
2748 const Obj_Entry *obj;
2749 RtldLockState lockstate;
2751 rlock_acquire(rtld_bind_lock, &lockstate);
2752 obj = obj_from_addr(addr);
2754 _rtld_error("No shared object contains address");
2755 lock_release(rtld_bind_lock, &lockstate);
2758 rtld_fill_dl_phdr_info(obj, phdr_info);
2759 lock_release(rtld_bind_lock, &lockstate);
2764 dladdr(const void *addr, Dl_info *info)
2766 const Obj_Entry *obj;
2769 unsigned long symoffset;
2770 RtldLockState lockstate;
2772 rlock_acquire(rtld_bind_lock, &lockstate);
2773 obj = obj_from_addr(addr);
2775 _rtld_error("No shared object contains address");
2776 lock_release(rtld_bind_lock, &lockstate);
2779 info->dli_fname = obj->path;
2780 info->dli_fbase = obj->mapbase;
2781 info->dli_saddr = (void *)0;
2782 info->dli_sname = NULL;
2785 * Walk the symbol list looking for the symbol whose address is
2786 * closest to the address sent in.
2788 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
2789 def = obj->symtab + symoffset;
2792 * For skip the symbol if st_shndx is either SHN_UNDEF or
2795 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2799 * If the symbol is greater than the specified address, or if it
2800 * is further away from addr than the current nearest symbol,
2803 symbol_addr = obj->relocbase + def->st_value;
2804 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2807 /* Update our idea of the nearest symbol. */
2808 info->dli_sname = obj->strtab + def->st_name;
2809 info->dli_saddr = symbol_addr;
2812 if (info->dli_saddr == addr)
2815 lock_release(rtld_bind_lock, &lockstate);
2820 dlinfo(void *handle, int request, void *p)
2822 const Obj_Entry *obj;
2823 RtldLockState lockstate;
2826 rlock_acquire(rtld_bind_lock, &lockstate);
2828 if (handle == NULL || handle == RTLD_SELF) {
2831 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2832 if ((obj = obj_from_addr(retaddr)) == NULL)
2833 _rtld_error("Cannot determine caller's shared object");
2835 obj = dlcheck(handle);
2838 lock_release(rtld_bind_lock, &lockstate);
2844 case RTLD_DI_LINKMAP:
2845 *((struct link_map const **)p) = &obj->linkmap;
2847 case RTLD_DI_ORIGIN:
2848 error = rtld_dirname(obj->path, p);
2851 case RTLD_DI_SERINFOSIZE:
2852 case RTLD_DI_SERINFO:
2853 error = do_search_info(obj, request, (struct dl_serinfo *)p);
2857 _rtld_error("Invalid request %d passed to dlinfo()", request);
2861 lock_release(rtld_bind_lock, &lockstate);
2867 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
2870 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
2871 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
2872 STAILQ_FIRST(&obj->names)->name : obj->path;
2873 phdr_info->dlpi_phdr = obj->phdr;
2874 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
2875 phdr_info->dlpi_tls_modid = obj->tlsindex;
2876 phdr_info->dlpi_tls_data = obj->tlsinit;
2877 phdr_info->dlpi_adds = obj_loads;
2878 phdr_info->dlpi_subs = obj_loads - obj_count;
2882 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
2884 struct dl_phdr_info phdr_info;
2885 const Obj_Entry *obj;
2886 RtldLockState bind_lockstate, phdr_lockstate;
2889 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
2890 rlock_acquire(rtld_bind_lock, &bind_lockstate);
2894 for (obj = obj_list; obj != NULL; obj = obj->next) {
2895 rtld_fill_dl_phdr_info(obj, &phdr_info);
2896 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
2900 lock_release(rtld_bind_lock, &bind_lockstate);
2901 lock_release(rtld_phdr_lock, &phdr_lockstate);
2906 struct fill_search_info_args {
2909 Dl_serinfo *serinfo;
2910 Dl_serpath *serpath;
2915 fill_search_info(const char *dir, size_t dirlen, void *param)
2917 struct fill_search_info_args *arg;
2921 if (arg->request == RTLD_DI_SERINFOSIZE) {
2922 arg->serinfo->dls_cnt ++;
2923 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
2925 struct dl_serpath *s_entry;
2927 s_entry = arg->serpath;
2928 s_entry->dls_name = arg->strspace;
2929 s_entry->dls_flags = arg->flags;
2931 strncpy(arg->strspace, dir, dirlen);
2932 arg->strspace[dirlen] = '\0';
2934 arg->strspace += dirlen + 1;
2942 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2944 struct dl_serinfo _info;
2945 struct fill_search_info_args args;
2947 args.request = RTLD_DI_SERINFOSIZE;
2948 args.serinfo = &_info;
2950 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2953 path_enumerate(ld_library_path, fill_search_info, &args);
2954 path_enumerate(obj->rpath, fill_search_info, &args);
2955 path_enumerate(gethints(), fill_search_info, &args);
2956 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
2959 if (request == RTLD_DI_SERINFOSIZE) {
2960 info->dls_size = _info.dls_size;
2961 info->dls_cnt = _info.dls_cnt;
2965 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
2966 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
2970 args.request = RTLD_DI_SERINFO;
2971 args.serinfo = info;
2972 args.serpath = &info->dls_serpath[0];
2973 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
2975 args.flags = LA_SER_LIBPATH;
2976 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
2979 args.flags = LA_SER_RUNPATH;
2980 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
2983 args.flags = LA_SER_CONFIG;
2984 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
2987 args.flags = LA_SER_DEFAULT;
2988 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
2994 rtld_dirname(const char *path, char *bname)
2998 /* Empty or NULL string gets treated as "." */
2999 if (path == NULL || *path == '\0') {
3005 /* Strip trailing slashes */
3006 endp = path + strlen(path) - 1;
3007 while (endp > path && *endp == '/')
3010 /* Find the start of the dir */
3011 while (endp > path && *endp != '/')
3014 /* Either the dir is "/" or there are no slashes */
3016 bname[0] = *endp == '/' ? '/' : '.';
3022 } while (endp > path && *endp == '/');
3025 if (endp - path + 2 > PATH_MAX)
3027 _rtld_error("Filename is too long: %s", path);
3031 strncpy(bname, path, endp - path + 1);
3032 bname[endp - path + 1] = '\0';
3037 rtld_dirname_abs(const char *path, char *base)
3039 char base_rel[PATH_MAX];
3041 if (rtld_dirname(path, base) == -1)
3045 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3046 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3047 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3049 strcpy(base, base_rel);
3054 linkmap_add(Obj_Entry *obj)
3056 struct link_map *l = &obj->linkmap;
3057 struct link_map *prev;
3059 obj->linkmap.l_name = obj->path;
3060 obj->linkmap.l_addr = obj->mapbase;
3061 obj->linkmap.l_ld = obj->dynamic;
3063 /* GDB needs load offset on MIPS to use the symbols */
3064 obj->linkmap.l_offs = obj->relocbase;
3067 if (r_debug.r_map == NULL) {
3073 * Scan to the end of the list, but not past the entry for the
3074 * dynamic linker, which we want to keep at the very end.
3076 for (prev = r_debug.r_map;
3077 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3078 prev = prev->l_next)
3081 /* Link in the new entry. */
3083 l->l_next = prev->l_next;
3084 if (l->l_next != NULL)
3085 l->l_next->l_prev = l;
3090 linkmap_delete(Obj_Entry *obj)
3092 struct link_map *l = &obj->linkmap;
3094 if (l->l_prev == NULL) {
3095 if ((r_debug.r_map = l->l_next) != NULL)
3096 l->l_next->l_prev = NULL;
3100 if ((l->l_prev->l_next = l->l_next) != NULL)
3101 l->l_next->l_prev = l->l_prev;
3105 * Function for the debugger to set a breakpoint on to gain control.
3107 * The two parameters allow the debugger to easily find and determine
3108 * what the runtime loader is doing and to whom it is doing it.
3110 * When the loadhook trap is hit (r_debug_state, set at program
3111 * initialization), the arguments can be found on the stack:
3113 * +8 struct link_map *m
3114 * +4 struct r_debug *rd
3118 r_debug_state(struct r_debug* rd, struct link_map *m)
3121 * The following is a hack to force the compiler to emit calls to
3122 * this function, even when optimizing. If the function is empty,
3123 * the compiler is not obliged to emit any code for calls to it,
3124 * even when marked __noinline. However, gdb depends on those
3127 __asm __volatile("" : : : "memory");
3131 * Get address of the pointer variable in the main program.
3132 * Prefer non-weak symbol over the weak one.
3134 static const void **
3135 get_program_var_addr(const char *name, RtldLockState *lockstate)
3140 symlook_init(&req, name);
3141 req.lockstate = lockstate;
3142 donelist_init(&donelist);
3143 if (symlook_global(&req, &donelist) != 0)
3145 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3146 return ((const void **)make_function_pointer(req.sym_out,
3148 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3149 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3151 return ((const void **)(req.defobj_out->relocbase +
3152 req.sym_out->st_value));
3156 * Set a pointer variable in the main program to the given value. This
3157 * is used to set key variables such as "environ" before any of the
3158 * init functions are called.
3161 set_program_var(const char *name, const void *value)
3165 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3166 dbg("\"%s\": *%p <-- %p", name, addr, value);
3172 * Search the global objects, including dependencies and main object,
3173 * for the given symbol.
3176 symlook_global(SymLook *req, DoneList *donelist)
3179 const Objlist_Entry *elm;
3182 symlook_init_from_req(&req1, req);
3184 /* Search all objects loaded at program start up. */
3185 if (req->defobj_out == NULL ||
3186 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3187 res = symlook_list(&req1, &list_main, donelist);
3188 if (res == 0 && (req->defobj_out == NULL ||
3189 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3190 req->sym_out = req1.sym_out;
3191 req->defobj_out = req1.defobj_out;
3192 assert(req->defobj_out != NULL);
3196 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3197 STAILQ_FOREACH(elm, &list_global, link) {
3198 if (req->defobj_out != NULL &&
3199 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3201 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3202 if (res == 0 && (req->defobj_out == NULL ||
3203 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3204 req->sym_out = req1.sym_out;
3205 req->defobj_out = req1.defobj_out;
3206 assert(req->defobj_out != NULL);
3210 return (req->sym_out != NULL ? 0 : ESRCH);
3214 * Given a symbol name in a referencing object, find the corresponding
3215 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3216 * no definition was found. Returns a pointer to the Obj_Entry of the
3217 * defining object via the reference parameter DEFOBJ_OUT.
3220 symlook_default(SymLook *req, const Obj_Entry *refobj)
3223 const Objlist_Entry *elm;
3227 donelist_init(&donelist);
3228 symlook_init_from_req(&req1, req);
3230 /* Look first in the referencing object if linked symbolically. */
3231 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3232 res = symlook_obj(&req1, refobj);
3234 req->sym_out = req1.sym_out;
3235 req->defobj_out = req1.defobj_out;
3236 assert(req->defobj_out != NULL);
3240 symlook_global(req, &donelist);
3242 /* Search all dlopened DAGs containing the referencing object. */
3243 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3244 if (req->sym_out != NULL &&
3245 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3247 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3248 if (res == 0 && (req->sym_out == NULL ||
3249 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3250 req->sym_out = req1.sym_out;
3251 req->defobj_out = req1.defobj_out;
3252 assert(req->defobj_out != NULL);
3257 * Search the dynamic linker itself, and possibly resolve the
3258 * symbol from there. This is how the application links to
3259 * dynamic linker services such as dlopen.
3261 if (req->sym_out == NULL ||
3262 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3263 res = symlook_obj(&req1, &obj_rtld);
3265 req->sym_out = req1.sym_out;
3266 req->defobj_out = req1.defobj_out;
3267 assert(req->defobj_out != NULL);
3271 return (req->sym_out != NULL ? 0 : ESRCH);
3275 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3278 const Obj_Entry *defobj;
3279 const Objlist_Entry *elm;
3285 STAILQ_FOREACH(elm, objlist, link) {
3286 if (donelist_check(dlp, elm->obj))
3288 symlook_init_from_req(&req1, req);
3289 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3290 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3292 defobj = req1.defobj_out;
3293 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3300 req->defobj_out = defobj;
3307 * Search the chain of DAGS cointed to by the given Needed_Entry
3308 * for a symbol of the given name. Each DAG is scanned completely
3309 * before advancing to the next one. Returns a pointer to the symbol,
3310 * or NULL if no definition was found.
3313 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3316 const Needed_Entry *n;
3317 const Obj_Entry *defobj;
3323 symlook_init_from_req(&req1, req);
3324 for (n = needed; n != NULL; n = n->next) {
3325 if (n->obj == NULL ||
3326 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3328 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3330 defobj = req1.defobj_out;
3331 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3337 req->defobj_out = defobj;
3344 * Search the symbol table of a single shared object for a symbol of
3345 * the given name and version, if requested. Returns a pointer to the
3346 * symbol, or NULL if no definition was found. If the object is
3347 * filter, return filtered symbol from filtee.
3349 * The symbol's hash value is passed in for efficiency reasons; that
3350 * eliminates many recomputations of the hash value.
3353 symlook_obj(SymLook *req, const Obj_Entry *obj)
3359 mres = symlook_obj1(req, obj);
3361 if (obj->needed_filtees != NULL) {
3362 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3363 donelist_init(&donelist);
3364 symlook_init_from_req(&req1, req);
3365 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3367 req->sym_out = req1.sym_out;
3368 req->defobj_out = req1.defobj_out;
3372 if (obj->needed_aux_filtees != NULL) {
3373 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3374 donelist_init(&donelist);
3375 symlook_init_from_req(&req1, req);
3376 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3378 req->sym_out = req1.sym_out;
3379 req->defobj_out = req1.defobj_out;
3388 symlook_obj1(SymLook *req, const Obj_Entry *obj)
3390 unsigned long symnum;
3391 const Elf_Sym *vsymp;
3395 if (obj->buckets == NULL)
3400 symnum = obj->buckets[req->hash % obj->nbuckets];
3402 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3403 const Elf_Sym *symp;
3406 if (symnum >= obj->nchains)
3407 return (ESRCH); /* Bad object */
3409 symp = obj->symtab + symnum;
3410 strp = obj->strtab + symp->st_name;
3412 switch (ELF_ST_TYPE(symp->st_info)) {
3417 if (symp->st_value == 0)
3421 if (symp->st_shndx != SHN_UNDEF)
3424 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3425 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3432 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3435 if (req->ventry == NULL) {
3436 if (obj->versyms != NULL) {
3437 verndx = VER_NDX(obj->versyms[symnum]);
3438 if (verndx > obj->vernum) {
3439 _rtld_error("%s: symbol %s references wrong version %d",
3440 obj->path, obj->strtab + symnum, verndx);
3444 * If we are not called from dlsym (i.e. this is a normal
3445 * relocation from unversioned binary), accept the symbol
3446 * immediately if it happens to have first version after
3447 * this shared object became versioned. Otherwise, if
3448 * symbol is versioned and not hidden, remember it. If it
3449 * is the only symbol with this name exported by the
3450 * shared object, it will be returned as a match at the
3451 * end of the function. If symbol is global (verndx < 2)
3452 * accept it unconditionally.
3454 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3455 verndx == VER_NDX_GIVEN) {
3456 req->sym_out = symp;
3457 req->defobj_out = obj;
3460 else if (verndx >= VER_NDX_GIVEN) {
3461 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
3469 req->sym_out = symp;
3470 req->defobj_out = obj;
3473 if (obj->versyms == NULL) {
3474 if (object_match_name(obj, req->ventry->name)) {
3475 _rtld_error("%s: object %s should provide version %s for "
3476 "symbol %s", obj_rtld.path, obj->path,
3477 req->ventry->name, obj->strtab + symnum);
3481 verndx = VER_NDX(obj->versyms[symnum]);
3482 if (verndx > obj->vernum) {
3483 _rtld_error("%s: symbol %s references wrong version %d",
3484 obj->path, obj->strtab + symnum, verndx);
3487 if (obj->vertab[verndx].hash != req->ventry->hash ||
3488 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3490 * Version does not match. Look if this is a global symbol
3491 * and if it is not hidden. If global symbol (verndx < 2)
3492 * is available, use it. Do not return symbol if we are
3493 * called by dlvsym, because dlvsym looks for a specific
3494 * version and default one is not what dlvsym wants.
3496 if ((req->flags & SYMLOOK_DLSYM) ||
3497 (obj->versyms[symnum] & VER_NDX_HIDDEN) ||
3498 (verndx >= VER_NDX_GIVEN))
3502 req->sym_out = symp;
3503 req->defobj_out = obj;
3508 req->sym_out = vsymp;
3509 req->defobj_out = obj;
3516 trace_loaded_objects(Obj_Entry *obj)
3518 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3521 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3524 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3525 fmt1 = "\t%o => %p (%x)\n";
3527 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3528 fmt2 = "\t%o (%x)\n";
3530 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
3532 for (; obj; obj = obj->next) {
3533 Needed_Entry *needed;
3537 if (list_containers && obj->needed != NULL)
3538 rtld_printf("%s:\n", obj->path);
3539 for (needed = obj->needed; needed; needed = needed->next) {
3540 if (needed->obj != NULL) {
3541 if (needed->obj->traced && !list_containers)
3543 needed->obj->traced = true;
3544 path = needed->obj->path;
3548 name = (char *)obj->strtab + needed->name;
3549 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3551 fmt = is_lib ? fmt1 : fmt2;
3552 while ((c = *fmt++) != '\0') {
3578 rtld_putstr(main_local);
3581 rtld_putstr(obj_main->path);
3588 rtld_printf("%d", sodp->sod_major);
3591 rtld_printf("%d", sodp->sod_minor);
3598 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
3611 * Unload a dlopened object and its dependencies from memory and from
3612 * our data structures. It is assumed that the DAG rooted in the
3613 * object has already been unreferenced, and that the object has a
3614 * reference count of 0.
3617 unload_object(Obj_Entry *root)
3622 assert(root->refcount == 0);
3625 * Pass over the DAG removing unreferenced objects from
3626 * appropriate lists.
3628 unlink_object(root);
3630 /* Unmap all objects that are no longer referenced. */
3631 linkp = &obj_list->next;
3632 while ((obj = *linkp) != NULL) {
3633 if (obj->refcount == 0) {
3634 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3636 dbg("unloading \"%s\"", obj->path);
3637 unload_filtees(root);
3638 munmap(obj->mapbase, obj->mapsize);
3639 linkmap_delete(obj);
3650 unlink_object(Obj_Entry *root)
3654 if (root->refcount == 0) {
3655 /* Remove the object from the RTLD_GLOBAL list. */
3656 objlist_remove(&list_global, root);
3658 /* Remove the object from all objects' DAG lists. */
3659 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3660 objlist_remove(&elm->obj->dldags, root);
3661 if (elm->obj != root)
3662 unlink_object(elm->obj);
3668 ref_dag(Obj_Entry *root)
3672 assert(root->dag_inited);
3673 STAILQ_FOREACH(elm, &root->dagmembers, link)
3674 elm->obj->refcount++;
3678 unref_dag(Obj_Entry *root)
3682 assert(root->dag_inited);
3683 STAILQ_FOREACH(elm, &root->dagmembers, link)
3684 elm->obj->refcount--;
3688 * Common code for MD __tls_get_addr().
3690 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
3692 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
3694 Elf_Addr *newdtv, *dtv;
3695 RtldLockState lockstate;
3699 /* Check dtv generation in case new modules have arrived */
3700 if (dtv[0] != tls_dtv_generation) {
3701 wlock_acquire(rtld_bind_lock, &lockstate);
3702 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3704 if (to_copy > tls_max_index)
3705 to_copy = tls_max_index;
3706 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
3707 newdtv[0] = tls_dtv_generation;
3708 newdtv[1] = tls_max_index;
3710 lock_release(rtld_bind_lock, &lockstate);
3711 dtv = *dtvp = newdtv;
3714 /* Dynamically allocate module TLS if necessary */
3715 if (dtv[index + 1] == 0) {
3716 /* Signal safe, wlock will block out signals. */
3717 wlock_acquire(rtld_bind_lock, &lockstate);
3718 if (!dtv[index + 1])
3719 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
3720 lock_release(rtld_bind_lock, &lockstate);
3722 return ((void *)(dtv[index + 1] + offset));
3726 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
3731 /* Check dtv generation in case new modules have arrived */
3732 if (__predict_true(dtv[0] == tls_dtv_generation &&
3733 dtv[index + 1] != 0))
3734 return ((void *)(dtv[index + 1] + offset));
3735 return (tls_get_addr_slow(dtvp, index, offset));
3738 /* XXX not sure what variants to use for arm. */
3740 #if defined(__ia64__) || defined(__powerpc__)
3743 * Allocate Static TLS using the Variant I method.
3746 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
3755 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
3758 assert(tcbsize >= TLS_TCB_SIZE);
3759 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
3760 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
3762 if (oldtcb != NULL) {
3763 memcpy(tls, oldtcb, tls_static_space);
3766 /* Adjust the DTV. */
3768 for (i = 0; i < dtv[1]; i++) {
3769 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
3770 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
3771 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
3775 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr));
3777 dtv[0] = tls_dtv_generation;
3778 dtv[1] = tls_max_index;
3780 for (obj = objs; obj; obj = obj->next) {
3781 if (obj->tlsoffset > 0) {
3782 addr = (Elf_Addr)tls + obj->tlsoffset;
3783 if (obj->tlsinitsize > 0)
3784 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3785 if (obj->tlssize > obj->tlsinitsize)
3786 memset((void*) (addr + obj->tlsinitsize), 0,
3787 obj->tlssize - obj->tlsinitsize);
3788 dtv[obj->tlsindex + 1] = addr;
3797 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
3800 Elf_Addr tlsstart, tlsend;
3803 assert(tcbsize >= TLS_TCB_SIZE);
3805 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
3806 tlsend = tlsstart + tls_static_space;
3808 dtv = *(Elf_Addr **)tlsstart;
3810 for (i = 0; i < dtvsize; i++) {
3811 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
3812 free((void*)dtv[i+2]);
3821 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
3822 defined(__arm__) || defined(__mips__)
3825 * Allocate Static TLS using the Variant II method.
3828 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
3833 Elf_Addr *dtv, *olddtv;
3834 Elf_Addr segbase, oldsegbase, addr;
3837 size = round(tls_static_space, tcbalign);
3839 assert(tcbsize >= 2*sizeof(Elf_Addr));
3840 tls = calloc(1, size + tcbsize);
3841 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3843 segbase = (Elf_Addr)(tls + size);
3844 ((Elf_Addr*)segbase)[0] = segbase;
3845 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
3847 dtv[0] = tls_dtv_generation;
3848 dtv[1] = tls_max_index;
3852 * Copy the static TLS block over whole.
3854 oldsegbase = (Elf_Addr) oldtls;
3855 memcpy((void *)(segbase - tls_static_space),
3856 (const void *)(oldsegbase - tls_static_space),
3860 * If any dynamic TLS blocks have been created tls_get_addr(),
3863 olddtv = ((Elf_Addr**)oldsegbase)[1];
3864 for (i = 0; i < olddtv[1]; i++) {
3865 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
3866 dtv[i+2] = olddtv[i+2];
3872 * We assume that this block was the one we created with
3873 * allocate_initial_tls().
3875 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
3877 for (obj = objs; obj; obj = obj->next) {
3878 if (obj->tlsoffset) {
3879 addr = segbase - obj->tlsoffset;
3880 memset((void*) (addr + obj->tlsinitsize),
3881 0, obj->tlssize - obj->tlsinitsize);
3883 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3884 dtv[obj->tlsindex + 1] = addr;
3889 return (void*) segbase;
3893 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
3898 Elf_Addr tlsstart, tlsend;
3901 * Figure out the size of the initial TLS block so that we can
3902 * find stuff which ___tls_get_addr() allocated dynamically.
3904 size = round(tls_static_space, tcbalign);
3906 dtv = ((Elf_Addr**)tls)[1];
3908 tlsend = (Elf_Addr) tls;
3909 tlsstart = tlsend - size;
3910 for (i = 0; i < dtvsize; i++) {
3911 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
3912 free((void*) dtv[i+2]);
3916 free((void*) tlsstart);
3923 * Allocate TLS block for module with given index.
3926 allocate_module_tls(int index)
3931 for (obj = obj_list; obj; obj = obj->next) {
3932 if (obj->tlsindex == index)
3936 _rtld_error("Can't find module with TLS index %d", index);
3940 p = malloc(obj->tlssize);
3942 _rtld_error("Cannot allocate TLS block for index %d", index);
3945 memcpy(p, obj->tlsinit, obj->tlsinitsize);
3946 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
3952 allocate_tls_offset(Obj_Entry *obj)
3959 if (obj->tlssize == 0) {
3960 obj->tls_done = true;
3964 if (obj->tlsindex == 1)
3965 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
3967 off = calculate_tls_offset(tls_last_offset, tls_last_size,
3968 obj->tlssize, obj->tlsalign);
3971 * If we have already fixed the size of the static TLS block, we
3972 * must stay within that size. When allocating the static TLS, we
3973 * leave a small amount of space spare to be used for dynamically
3974 * loading modules which use static TLS.
3976 if (tls_static_space) {
3977 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
3981 tls_last_offset = obj->tlsoffset = off;
3982 tls_last_size = obj->tlssize;
3983 obj->tls_done = true;
3989 free_tls_offset(Obj_Entry *obj)
3993 * If we were the last thing to allocate out of the static TLS
3994 * block, we give our space back to the 'allocator'. This is a
3995 * simplistic workaround to allow libGL.so.1 to be loaded and
3996 * unloaded multiple times.
3998 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
3999 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4000 tls_last_offset -= obj->tlssize;
4006 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4009 RtldLockState lockstate;
4011 wlock_acquire(rtld_bind_lock, &lockstate);
4012 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4013 lock_release(rtld_bind_lock, &lockstate);
4018 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4020 RtldLockState lockstate;
4022 wlock_acquire(rtld_bind_lock, &lockstate);
4023 free_tls(tcb, tcbsize, tcbalign);
4024 lock_release(rtld_bind_lock, &lockstate);
4028 object_add_name(Obj_Entry *obj, const char *name)
4034 entry = malloc(sizeof(Name_Entry) + len);
4036 if (entry != NULL) {
4037 strcpy(entry->name, name);
4038 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4043 object_match_name(const Obj_Entry *obj, const char *name)
4047 STAILQ_FOREACH(entry, &obj->names, link) {
4048 if (strcmp(name, entry->name) == 0)
4055 locate_dependency(const Obj_Entry *obj, const char *name)
4057 const Objlist_Entry *entry;
4058 const Needed_Entry *needed;
4060 STAILQ_FOREACH(entry, &list_main, link) {
4061 if (object_match_name(entry->obj, name))
4065 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4066 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4067 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4069 * If there is DT_NEEDED for the name we are looking for,
4070 * we are all set. Note that object might not be found if
4071 * dependency was not loaded yet, so the function can
4072 * return NULL here. This is expected and handled
4073 * properly by the caller.
4075 return (needed->obj);
4078 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4084 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4085 const Elf_Vernaux *vna)
4087 const Elf_Verdef *vd;
4088 const char *vername;
4090 vername = refobj->strtab + vna->vna_name;
4091 vd = depobj->verdef;
4093 _rtld_error("%s: version %s required by %s not defined",
4094 depobj->path, vername, refobj->path);
4098 if (vd->vd_version != VER_DEF_CURRENT) {
4099 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4100 depobj->path, vd->vd_version);
4103 if (vna->vna_hash == vd->vd_hash) {
4104 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4105 ((char *)vd + vd->vd_aux);
4106 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4109 if (vd->vd_next == 0)
4111 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4113 if (vna->vna_flags & VER_FLG_WEAK)
4115 _rtld_error("%s: version %s required by %s not found",
4116 depobj->path, vername, refobj->path);
4121 rtld_verify_object_versions(Obj_Entry *obj)
4123 const Elf_Verneed *vn;
4124 const Elf_Verdef *vd;
4125 const Elf_Verdaux *vda;
4126 const Elf_Vernaux *vna;
4127 const Obj_Entry *depobj;
4128 int maxvernum, vernum;
4132 * Walk over defined and required version records and figure out
4133 * max index used by any of them. Do very basic sanity checking
4137 while (vn != NULL) {
4138 if (vn->vn_version != VER_NEED_CURRENT) {
4139 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4140 obj->path, vn->vn_version);
4143 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4145 vernum = VER_NEED_IDX(vna->vna_other);
4146 if (vernum > maxvernum)
4148 if (vna->vna_next == 0)
4150 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4152 if (vn->vn_next == 0)
4154 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4158 while (vd != NULL) {
4159 if (vd->vd_version != VER_DEF_CURRENT) {
4160 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4161 obj->path, vd->vd_version);
4164 vernum = VER_DEF_IDX(vd->vd_ndx);
4165 if (vernum > maxvernum)
4167 if (vd->vd_next == 0)
4169 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4176 * Store version information in array indexable by version index.
4177 * Verify that object version requirements are satisfied along the
4180 obj->vernum = maxvernum + 1;
4181 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry));
4184 while (vd != NULL) {
4185 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4186 vernum = VER_DEF_IDX(vd->vd_ndx);
4187 assert(vernum <= maxvernum);
4188 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4189 obj->vertab[vernum].hash = vd->vd_hash;
4190 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4191 obj->vertab[vernum].file = NULL;
4192 obj->vertab[vernum].flags = 0;
4194 if (vd->vd_next == 0)
4196 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4200 while (vn != NULL) {
4201 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4204 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4206 if (check_object_provided_version(obj, depobj, vna))
4208 vernum = VER_NEED_IDX(vna->vna_other);
4209 assert(vernum <= maxvernum);
4210 obj->vertab[vernum].hash = vna->vna_hash;
4211 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4212 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4213 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4214 VER_INFO_HIDDEN : 0;
4215 if (vna->vna_next == 0)
4217 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4219 if (vn->vn_next == 0)
4221 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4227 rtld_verify_versions(const Objlist *objlist)
4229 Objlist_Entry *entry;
4233 STAILQ_FOREACH(entry, objlist, link) {
4235 * Skip dummy objects or objects that have their version requirements
4238 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4240 if (rtld_verify_object_versions(entry->obj) == -1) {
4242 if (ld_tracing == NULL)
4246 if (rc == 0 || ld_tracing != NULL)
4247 rc = rtld_verify_object_versions(&obj_rtld);
4252 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4257 vernum = VER_NDX(obj->versyms[symnum]);
4258 if (vernum >= obj->vernum) {
4259 _rtld_error("%s: symbol %s has wrong verneed value %d",
4260 obj->path, obj->strtab + symnum, vernum);
4261 } else if (obj->vertab[vernum].hash != 0) {
4262 return &obj->vertab[vernum];
4269 _rtld_get_stack_prot(void)
4272 return (stack_prot);
4276 map_stacks_exec(RtldLockState *lockstate)
4278 void (*thr_map_stacks_exec)(void);
4280 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4282 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4283 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4284 if (thr_map_stacks_exec != NULL) {
4285 stack_prot |= PROT_EXEC;
4286 thr_map_stacks_exec();
4291 symlook_init(SymLook *dst, const char *name)
4294 bzero(dst, sizeof(*dst));
4296 dst->hash = elf_hash(name);
4300 symlook_init_from_req(SymLook *dst, const SymLook *src)
4303 dst->name = src->name;
4304 dst->hash = src->hash;
4305 dst->ventry = src->ventry;
4306 dst->flags = src->flags;
4307 dst->defobj_out = NULL;
4308 dst->sym_out = NULL;
4309 dst->lockstate = src->lockstate;
4313 * Overrides for libc_pic-provided functions.
4317 __getosreldate(void)
4327 oid[1] = KERN_OSRELDATE;
4329 len = sizeof(osrel);
4330 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4331 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4337 * No unresolved symbols for rtld.
4340 __pthread_cxa_finalize(struct dl_phdr_info *a)
4345 __stack_chk_fail(void)
4348 _rtld_error("stack overflow detected; terminated");
4356 _rtld_error("buffer overflow detected; terminated");
4361 rtld_strerror(int errnum)
4364 if (errnum < 0 || errnum >= sys_nerr)
4365 return ("Unknown error");
4366 return (sys_errlist[errnum]);