2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
37 #include <sys/param.h>
38 #include <sys/mount.h>
41 #include <sys/sysctl.h>
43 #include <sys/utsname.h>
44 #include <sys/ktrace.h>
60 #include "rtld_printf.h"
64 #define PATH_RTLD "/libexec/ld-elf.so.1"
66 #define PATH_RTLD "/libexec/ld-elf32.so.1"
70 typedef void (*func_ptr_type)();
71 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
74 * Function declarations.
76 static const char *basename(const char *);
77 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
78 const Elf_Dyn **, const Elf_Dyn **);
79 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
81 static void digest_dynamic(Obj_Entry *, int);
82 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
83 static Obj_Entry *dlcheck(void *);
84 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
85 int lo_flags, int mode, RtldLockState *lockstate);
86 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
87 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
88 static bool donelist_check(DoneList *, const Obj_Entry *);
89 static void errmsg_restore(char *);
90 static char *errmsg_save(void);
91 static void *fill_search_info(const char *, size_t, void *);
92 static char *find_library(const char *, const Obj_Entry *);
93 static const char *gethints(bool);
94 static void init_dag(Obj_Entry *);
95 static void init_pagesizes(Elf_Auxinfo **aux_info);
96 static void init_rtld(caddr_t, Elf_Auxinfo **);
97 static void initlist_add_neededs(Needed_Entry *, Objlist *);
98 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
99 static void linkmap_add(Obj_Entry *);
100 static void linkmap_delete(Obj_Entry *);
101 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
102 static void unload_filtees(Obj_Entry *);
103 static int load_needed_objects(Obj_Entry *, int);
104 static int load_preload_objects(void);
105 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
106 static void map_stacks_exec(RtldLockState *);
107 static Obj_Entry *obj_from_addr(const void *);
108 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
109 static void objlist_call_init(Objlist *, RtldLockState *);
110 static void objlist_clear(Objlist *);
111 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
112 static void objlist_init(Objlist *);
113 static void objlist_push_head(Objlist *, Obj_Entry *);
114 static void objlist_push_tail(Objlist *, Obj_Entry *);
115 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
116 static void objlist_remove(Objlist *, Obj_Entry *);
117 static void *path_enumerate(const char *, path_enum_proc, void *);
118 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
119 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
120 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
121 int flags, RtldLockState *lockstate);
122 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
124 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
125 int flags, RtldLockState *lockstate);
126 static int rtld_dirname(const char *, char *);
127 static int rtld_dirname_abs(const char *, char *);
128 static void *rtld_dlopen(const char *name, int fd, int mode);
129 static void rtld_exit(void);
130 static char *search_library_path(const char *, const char *);
131 static const void **get_program_var_addr(const char *, RtldLockState *);
132 static void set_program_var(const char *, const void *);
133 static int symlook_default(SymLook *, const Obj_Entry *refobj);
134 static int symlook_global(SymLook *, DoneList *);
135 static void symlook_init_from_req(SymLook *, const SymLook *);
136 static int symlook_list(SymLook *, const Objlist *, DoneList *);
137 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
138 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
139 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
140 static void trace_loaded_objects(Obj_Entry *);
141 static void unlink_object(Obj_Entry *);
142 static void unload_object(Obj_Entry *);
143 static void unref_dag(Obj_Entry *);
144 static void ref_dag(Obj_Entry *);
145 static char *origin_subst_one(Obj_Entry *, char *, const char *,
147 static char *origin_subst(Obj_Entry *, char *);
148 static bool obj_resolve_origin(Obj_Entry *obj);
149 static void preinit_main(void);
150 static int rtld_verify_versions(const Objlist *);
151 static int rtld_verify_object_versions(Obj_Entry *);
152 static void object_add_name(Obj_Entry *, const char *);
153 static int object_match_name(const Obj_Entry *, const char *);
154 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
155 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
156 struct dl_phdr_info *phdr_info);
157 static uint32_t gnu_hash(const char *);
158 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
159 const unsigned long);
161 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
162 void _r_debug_postinit(struct link_map *) __noinline __exported;
167 static char *error_message; /* Message for dlerror(), or NULL */
168 struct r_debug r_debug __exported; /* for GDB; */
169 static bool libmap_disable; /* Disable libmap */
170 static bool ld_loadfltr; /* Immediate filters processing */
171 static char *libmap_override; /* Maps to use in addition to libmap.conf */
172 static bool trust; /* False for setuid and setgid programs */
173 static bool dangerous_ld_env; /* True if environment variables have been
174 used to affect the libraries loaded */
175 static char *ld_bind_now; /* Environment variable for immediate binding */
176 static char *ld_debug; /* Environment variable for debugging */
177 static char *ld_library_path; /* Environment variable for search path */
178 static char *ld_preload; /* Environment variable for libraries to
180 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
181 static char *ld_tracing; /* Called from ldd to print libs */
182 static char *ld_utrace; /* Use utrace() to log events. */
183 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
184 static Obj_Entry *obj_main; /* The main program shared object */
185 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
186 static unsigned int obj_count; /* Number of objects in obj_list */
187 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
189 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
190 STAILQ_HEAD_INITIALIZER(list_global);
191 static Objlist list_main = /* Objects loaded at program startup */
192 STAILQ_HEAD_INITIALIZER(list_main);
193 static Objlist list_fini = /* Objects needing fini() calls */
194 STAILQ_HEAD_INITIALIZER(list_fini);
196 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
198 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
200 extern Elf_Dyn _DYNAMIC;
201 #pragma weak _DYNAMIC
202 #ifndef RTLD_IS_DYNAMIC
203 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
206 int dlclose(void *) __exported;
207 char *dlerror(void) __exported;
208 void *dlopen(const char *, int) __exported;
209 void *fdlopen(int, int) __exported;
210 void *dlsym(void *, const char *) __exported;
211 dlfunc_t dlfunc(void *, const char *) __exported;
212 void *dlvsym(void *, const char *, const char *) __exported;
213 int dladdr(const void *, Dl_info *) __exported;
214 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
215 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
216 int dlinfo(void *, int , void *) __exported;
217 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
218 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
219 int _rtld_get_stack_prot(void) __exported;
220 int _rtld_is_dlopened(void *) __exported;
221 void _rtld_error(const char *, ...) __exported;
223 int npagesizes, osreldate;
226 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
228 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
229 static int max_stack_flags;
232 * Global declarations normally provided by crt1. The dynamic linker is
233 * not built with crt1, so we have to provide them ourselves.
239 * Used to pass argc, argv to init functions.
245 * Globals to control TLS allocation.
247 size_t tls_last_offset; /* Static TLS offset of last module */
248 size_t tls_last_size; /* Static TLS size of last module */
249 size_t tls_static_space; /* Static TLS space allocated */
250 size_t tls_static_max_align;
251 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
252 int tls_max_index = 1; /* Largest module index allocated */
254 bool ld_library_path_rpath = false;
257 * Fill in a DoneList with an allocation large enough to hold all of
258 * the currently-loaded objects. Keep this as a macro since it calls
259 * alloca and we want that to occur within the scope of the caller.
261 #define donelist_init(dlp) \
262 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
263 assert((dlp)->objs != NULL), \
264 (dlp)->num_alloc = obj_count, \
267 #define UTRACE_DLOPEN_START 1
268 #define UTRACE_DLOPEN_STOP 2
269 #define UTRACE_DLCLOSE_START 3
270 #define UTRACE_DLCLOSE_STOP 4
271 #define UTRACE_LOAD_OBJECT 5
272 #define UTRACE_UNLOAD_OBJECT 6
273 #define UTRACE_ADD_RUNDEP 7
274 #define UTRACE_PRELOAD_FINISHED 8
275 #define UTRACE_INIT_CALL 9
276 #define UTRACE_FINI_CALL 10
277 #define UTRACE_DLSYM_START 11
278 #define UTRACE_DLSYM_STOP 12
281 char sig[4]; /* 'RTLD' */
284 void *mapbase; /* Used for 'parent' and 'init/fini' */
286 int refcnt; /* Used for 'mode' */
287 char name[MAXPATHLEN];
290 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
291 if (ld_utrace != NULL) \
292 ld_utrace_log(e, h, mb, ms, r, n); \
296 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
297 int refcnt, const char *name)
299 struct utrace_rtld ut;
307 ut.mapbase = mapbase;
308 ut.mapsize = mapsize;
310 bzero(ut.name, sizeof(ut.name));
312 strlcpy(ut.name, name, sizeof(ut.name));
313 utrace(&ut, sizeof(ut));
317 * Main entry point for dynamic linking. The first argument is the
318 * stack pointer. The stack is expected to be laid out as described
319 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
320 * Specifically, the stack pointer points to a word containing
321 * ARGC. Following that in the stack is a null-terminated sequence
322 * of pointers to argument strings. Then comes a null-terminated
323 * sequence of pointers to environment strings. Finally, there is a
324 * sequence of "auxiliary vector" entries.
326 * The second argument points to a place to store the dynamic linker's
327 * exit procedure pointer and the third to a place to store the main
330 * The return value is the main program's entry point.
333 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
335 Elf_Auxinfo *aux_info[AT_COUNT];
343 Objlist_Entry *entry;
345 Obj_Entry *preload_tail;
346 Obj_Entry *last_interposer;
348 RtldLockState lockstate;
349 char *library_path_rpath;
354 * On entry, the dynamic linker itself has not been relocated yet.
355 * Be very careful not to reference any global data until after
356 * init_rtld has returned. It is OK to reference file-scope statics
357 * and string constants, and to call static and global functions.
360 /* Find the auxiliary vector on the stack. */
363 sp += argc + 1; /* Skip over arguments and NULL terminator */
365 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
367 aux = (Elf_Auxinfo *) sp;
369 /* Digest the auxiliary vector. */
370 for (i = 0; i < AT_COUNT; i++)
372 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
373 if (auxp->a_type < AT_COUNT)
374 aux_info[auxp->a_type] = auxp;
377 /* Initialize and relocate ourselves. */
378 assert(aux_info[AT_BASE] != NULL);
379 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
381 __progname = obj_rtld.path;
382 argv0 = argv[0] != NULL ? argv[0] : "(null)";
387 if (aux_info[AT_CANARY] != NULL &&
388 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
389 i = aux_info[AT_CANARYLEN]->a_un.a_val;
390 if (i > sizeof(__stack_chk_guard))
391 i = sizeof(__stack_chk_guard);
392 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
397 len = sizeof(__stack_chk_guard);
398 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
399 len != sizeof(__stack_chk_guard)) {
400 /* If sysctl was unsuccessful, use the "terminator canary". */
401 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
402 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
403 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
404 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
408 trust = !issetugid();
410 ld_bind_now = getenv(LD_ "BIND_NOW");
412 * If the process is tainted, then we un-set the dangerous environment
413 * variables. The process will be marked as tainted until setuid(2)
414 * is called. If any child process calls setuid(2) we do not want any
415 * future processes to honor the potentially un-safe variables.
418 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
419 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
420 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
421 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
422 _rtld_error("environment corrupt; aborting");
426 ld_debug = getenv(LD_ "DEBUG");
427 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
428 libmap_override = getenv(LD_ "LIBMAP");
429 ld_library_path = getenv(LD_ "LIBRARY_PATH");
430 ld_preload = getenv(LD_ "PRELOAD");
431 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
432 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
433 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
434 if (library_path_rpath != NULL) {
435 if (library_path_rpath[0] == 'y' ||
436 library_path_rpath[0] == 'Y' ||
437 library_path_rpath[0] == '1')
438 ld_library_path_rpath = true;
440 ld_library_path_rpath = false;
442 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
443 (ld_library_path != NULL) || (ld_preload != NULL) ||
444 (ld_elf_hints_path != NULL) || ld_loadfltr;
445 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
446 ld_utrace = getenv(LD_ "UTRACE");
448 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
449 ld_elf_hints_path = _PATH_ELF_HINTS;
451 if (ld_debug != NULL && *ld_debug != '\0')
453 dbg("%s is initialized, base address = %p", __progname,
454 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
455 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
456 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
458 dbg("initializing thread locks");
462 * Load the main program, or process its program header if it is
465 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
466 int fd = aux_info[AT_EXECFD]->a_un.a_val;
467 dbg("loading main program");
468 obj_main = map_object(fd, argv0, NULL);
470 if (obj_main == NULL)
472 max_stack_flags = obj->stack_flags;
473 } else { /* Main program already loaded. */
474 const Elf_Phdr *phdr;
478 dbg("processing main program's program header");
479 assert(aux_info[AT_PHDR] != NULL);
480 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
481 assert(aux_info[AT_PHNUM] != NULL);
482 phnum = aux_info[AT_PHNUM]->a_un.a_val;
483 assert(aux_info[AT_PHENT] != NULL);
484 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
485 assert(aux_info[AT_ENTRY] != NULL);
486 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
487 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
491 if (aux_info[AT_EXECPATH] != 0) {
493 char buf[MAXPATHLEN];
495 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
496 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
497 if (kexecpath[0] == '/')
498 obj_main->path = kexecpath;
499 else if (getcwd(buf, sizeof(buf)) == NULL ||
500 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
501 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
502 obj_main->path = xstrdup(argv0);
504 obj_main->path = xstrdup(buf);
506 dbg("No AT_EXECPATH");
507 obj_main->path = xstrdup(argv0);
509 dbg("obj_main path %s", obj_main->path);
510 obj_main->mainprog = true;
512 if (aux_info[AT_STACKPROT] != NULL &&
513 aux_info[AT_STACKPROT]->a_un.a_val != 0)
514 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
518 * Get the actual dynamic linker pathname from the executable if
519 * possible. (It should always be possible.) That ensures that
520 * gdb will find the right dynamic linker even if a non-standard
523 if (obj_main->interp != NULL &&
524 strcmp(obj_main->interp, obj_rtld.path) != 0) {
526 obj_rtld.path = xstrdup(obj_main->interp);
527 __progname = obj_rtld.path;
531 digest_dynamic(obj_main, 0);
532 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
533 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
534 obj_main->dynsymcount);
536 linkmap_add(obj_main);
537 linkmap_add(&obj_rtld);
539 /* Link the main program into the list of objects. */
540 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
544 /* Initialize a fake symbol for resolving undefined weak references. */
545 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
546 sym_zero.st_shndx = SHN_UNDEF;
547 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
550 libmap_disable = (bool)lm_init(libmap_override);
552 dbg("loading LD_PRELOAD libraries");
553 if (load_preload_objects() == -1)
555 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
557 dbg("loading needed objects");
558 if (load_needed_objects(obj_main, 0) == -1)
561 /* Make a list of all objects loaded at startup. */
562 last_interposer = obj_main;
563 TAILQ_FOREACH(obj, &obj_list, next) {
566 if (obj->z_interpose && obj != obj_main) {
567 objlist_put_after(&list_main, last_interposer, obj);
568 last_interposer = obj;
570 objlist_push_tail(&list_main, obj);
575 dbg("checking for required versions");
576 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
579 if (ld_tracing) { /* We're done */
580 trace_loaded_objects(obj_main);
584 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
585 dump_relocations(obj_main);
590 * Processing tls relocations requires having the tls offsets
591 * initialized. Prepare offsets before starting initial
592 * relocation processing.
594 dbg("initializing initial thread local storage offsets");
595 STAILQ_FOREACH(entry, &list_main, link) {
597 * Allocate all the initial objects out of the static TLS
598 * block even if they didn't ask for it.
600 allocate_tls_offset(entry->obj);
603 if (relocate_objects(obj_main,
604 ld_bind_now != NULL && *ld_bind_now != '\0',
605 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
608 dbg("doing copy relocations");
609 if (do_copy_relocations(obj_main) == -1)
612 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
613 dump_relocations(obj_main);
618 * Setup TLS for main thread. This must be done after the
619 * relocations are processed, since tls initialization section
620 * might be the subject for relocations.
622 dbg("initializing initial thread local storage");
623 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
625 dbg("initializing key program variables");
626 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
627 set_program_var("environ", env);
628 set_program_var("__elf_aux_vector", aux);
630 /* Make a list of init functions to call. */
631 objlist_init(&initlist);
632 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
633 preload_tail, &initlist);
635 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
637 map_stacks_exec(NULL);
639 dbg("resolving ifuncs");
640 if (resolve_objects_ifunc(obj_main,
641 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
645 if (!obj_main->crt_no_init) {
647 * Make sure we don't call the main program's init and fini
648 * functions for binaries linked with old crt1 which calls
651 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
652 obj_main->preinit_array = obj_main->init_array =
653 obj_main->fini_array = (Elf_Addr)NULL;
656 wlock_acquire(rtld_bind_lock, &lockstate);
657 if (obj_main->crt_no_init)
659 objlist_call_init(&initlist, &lockstate);
660 _r_debug_postinit(&obj_main->linkmap);
661 objlist_clear(&initlist);
662 dbg("loading filtees");
663 TAILQ_FOREACH(obj, &obj_list, next) {
666 if (ld_loadfltr || obj->z_loadfltr)
667 load_filtees(obj, 0, &lockstate);
669 lock_release(rtld_bind_lock, &lockstate);
671 dbg("transferring control to program entry point = %p", obj_main->entry);
673 /* Return the exit procedure and the program entry point. */
674 *exit_proc = rtld_exit;
676 return (func_ptr_type) obj_main->entry;
680 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
685 ptr = (void *)make_function_pointer(def, obj);
686 target = ((Elf_Addr (*)(void))ptr)();
687 return ((void *)target);
691 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
695 const Obj_Entry *defobj;
698 RtldLockState lockstate;
700 rlock_acquire(rtld_bind_lock, &lockstate);
701 if (sigsetjmp(lockstate.env, 0) != 0)
702 lock_upgrade(rtld_bind_lock, &lockstate);
704 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
706 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
708 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
709 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
713 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
714 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
716 target = (Elf_Addr)(defobj->relocbase + def->st_value);
718 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
719 defobj->strtab + def->st_name, basename(obj->path),
720 (void *)target, basename(defobj->path));
723 * Write the new contents for the jmpslot. Note that depending on
724 * architecture, the value which we need to return back to the
725 * lazy binding trampoline may or may not be the target
726 * address. The value returned from reloc_jmpslot() is the value
727 * that the trampoline needs.
729 target = reloc_jmpslot(where, target, defobj, obj, rel);
730 lock_release(rtld_bind_lock, &lockstate);
735 * Error reporting function. Use it like printf. If formats the message
736 * into a buffer, and sets things up so that the next call to dlerror()
737 * will return the message.
740 _rtld_error(const char *fmt, ...)
742 static char buf[512];
746 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
752 * Return a dynamically-allocated copy of the current error message, if any.
757 return error_message == NULL ? NULL : xstrdup(error_message);
761 * Restore the current error message from a copy which was previously saved
762 * by errmsg_save(). The copy is freed.
765 errmsg_restore(char *saved_msg)
767 if (saved_msg == NULL)
768 error_message = NULL;
770 _rtld_error("%s", saved_msg);
776 basename(const char *name)
778 const char *p = strrchr(name, '/');
779 return p != NULL ? p + 1 : name;
782 static struct utsname uts;
785 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
786 const char *subst, bool may_free)
788 char *p, *p1, *res, *resp;
789 int subst_len, kw_len, subst_count, old_len, new_len;
794 * First, count the number of the keyword occurences, to
795 * preallocate the final string.
797 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
804 * If the keyword is not found, just return.
806 * Return non-substituted string if resolution failed. We
807 * cannot do anything more reasonable, the failure mode of the
808 * caller is unresolved library anyway.
810 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
811 return (may_free ? real : xstrdup(real));
813 subst = obj->origin_path;
816 * There is indeed something to substitute. Calculate the
817 * length of the resulting string, and allocate it.
819 subst_len = strlen(subst);
820 old_len = strlen(real);
821 new_len = old_len + (subst_len - kw_len) * subst_count;
822 res = xmalloc(new_len + 1);
825 * Now, execute the substitution loop.
827 for (p = real, resp = res, *resp = '\0';;) {
830 /* Copy the prefix before keyword. */
831 memcpy(resp, p, p1 - p);
833 /* Keyword replacement. */
834 memcpy(resp, subst, subst_len);
842 /* Copy to the end of string and finish. */
850 origin_subst(Obj_Entry *obj, char *real)
852 char *res1, *res2, *res3, *res4;
854 if (obj == NULL || !trust)
855 return (xstrdup(real));
856 if (uts.sysname[0] == '\0') {
857 if (uname(&uts) != 0) {
858 _rtld_error("utsname failed: %d", errno);
862 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
863 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
864 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
865 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
872 const char *msg = dlerror();
876 rtld_fdputstr(STDERR_FILENO, msg);
877 rtld_fdputchar(STDERR_FILENO, '\n');
882 * Process a shared object's DYNAMIC section, and save the important
883 * information in its Obj_Entry structure.
886 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
887 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
890 Needed_Entry **needed_tail = &obj->needed;
891 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
892 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
893 const Elf_Hashelt *hashtab;
894 const Elf32_Word *hashval;
895 Elf32_Word bkt, nmaskwords;
897 int plttype = DT_REL;
903 obj->bind_now = false;
904 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
905 switch (dynp->d_tag) {
908 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
912 obj->relsize = dynp->d_un.d_val;
916 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
920 obj->pltrel = (const Elf_Rel *)
921 (obj->relocbase + dynp->d_un.d_ptr);
925 obj->pltrelsize = dynp->d_un.d_val;
929 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
933 obj->relasize = dynp->d_un.d_val;
937 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
941 plttype = dynp->d_un.d_val;
942 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
946 obj->symtab = (const Elf_Sym *)
947 (obj->relocbase + dynp->d_un.d_ptr);
951 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
955 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
959 obj->strsize = dynp->d_un.d_val;
963 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
968 obj->verneednum = dynp->d_un.d_val;
972 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
977 obj->verdefnum = dynp->d_un.d_val;
981 obj->versyms = (const Elf_Versym *)(obj->relocbase +
987 hashtab = (const Elf_Hashelt *)(obj->relocbase +
989 obj->nbuckets = hashtab[0];
990 obj->nchains = hashtab[1];
991 obj->buckets = hashtab + 2;
992 obj->chains = obj->buckets + obj->nbuckets;
993 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
994 obj->buckets != NULL;
1000 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1002 obj->nbuckets_gnu = hashtab[0];
1003 obj->symndx_gnu = hashtab[1];
1004 nmaskwords = hashtab[2];
1005 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1006 obj->maskwords_bm_gnu = nmaskwords - 1;
1007 obj->shift2_gnu = hashtab[3];
1008 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1009 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1010 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1012 /* Number of bitmask words is required to be power of 2 */
1013 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1014 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1020 Needed_Entry *nep = NEW(Needed_Entry);
1021 nep->name = dynp->d_un.d_val;
1026 needed_tail = &nep->next;
1032 Needed_Entry *nep = NEW(Needed_Entry);
1033 nep->name = dynp->d_un.d_val;
1037 *needed_filtees_tail = nep;
1038 needed_filtees_tail = &nep->next;
1044 Needed_Entry *nep = NEW(Needed_Entry);
1045 nep->name = dynp->d_un.d_val;
1049 *needed_aux_filtees_tail = nep;
1050 needed_aux_filtees_tail = &nep->next;
1055 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1059 obj->textrel = true;
1063 obj->symbolic = true;
1068 * We have to wait until later to process this, because we
1069 * might not have gotten the address of the string table yet.
1079 *dyn_runpath = dynp;
1083 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1086 case DT_PREINIT_ARRAY:
1087 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1090 case DT_PREINIT_ARRAYSZ:
1091 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1095 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1098 case DT_INIT_ARRAYSZ:
1099 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1103 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1107 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1110 case DT_FINI_ARRAYSZ:
1111 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1115 * Don't process DT_DEBUG on MIPS as the dynamic section
1116 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1122 dbg("Filling in DT_DEBUG entry");
1123 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1128 if (dynp->d_un.d_val & DF_ORIGIN)
1129 obj->z_origin = true;
1130 if (dynp->d_un.d_val & DF_SYMBOLIC)
1131 obj->symbolic = true;
1132 if (dynp->d_un.d_val & DF_TEXTREL)
1133 obj->textrel = true;
1134 if (dynp->d_un.d_val & DF_BIND_NOW)
1135 obj->bind_now = true;
1136 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1140 case DT_MIPS_LOCAL_GOTNO:
1141 obj->local_gotno = dynp->d_un.d_val;
1144 case DT_MIPS_SYMTABNO:
1145 obj->symtabno = dynp->d_un.d_val;
1148 case DT_MIPS_GOTSYM:
1149 obj->gotsym = dynp->d_un.d_val;
1152 case DT_MIPS_RLD_MAP:
1153 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1158 if (dynp->d_un.d_val & DF_1_NOOPEN)
1159 obj->z_noopen = true;
1160 if (dynp->d_un.d_val & DF_1_ORIGIN)
1161 obj->z_origin = true;
1162 if (dynp->d_un.d_val & DF_1_GLOBAL)
1163 obj->z_global = true;
1164 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1165 obj->bind_now = true;
1166 if (dynp->d_un.d_val & DF_1_NODELETE)
1167 obj->z_nodelete = true;
1168 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1169 obj->z_loadfltr = true;
1170 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1171 obj->z_interpose = true;
1172 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1173 obj->z_nodeflib = true;
1178 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1185 obj->traced = false;
1187 if (plttype == DT_RELA) {
1188 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1190 obj->pltrelasize = obj->pltrelsize;
1191 obj->pltrelsize = 0;
1194 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1195 if (obj->valid_hash_sysv)
1196 obj->dynsymcount = obj->nchains;
1197 else if (obj->valid_hash_gnu) {
1198 obj->dynsymcount = 0;
1199 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1200 if (obj->buckets_gnu[bkt] == 0)
1202 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1205 while ((*hashval++ & 1u) == 0);
1207 obj->dynsymcount += obj->symndx_gnu;
1212 obj_resolve_origin(Obj_Entry *obj)
1215 if (obj->origin_path != NULL)
1217 obj->origin_path = xmalloc(PATH_MAX);
1218 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1222 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1223 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1226 if (obj->z_origin && !obj_resolve_origin(obj))
1229 if (dyn_runpath != NULL) {
1230 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1231 obj->runpath = origin_subst(obj, obj->runpath);
1232 } else if (dyn_rpath != NULL) {
1233 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1234 obj->rpath = origin_subst(obj, obj->rpath);
1236 if (dyn_soname != NULL)
1237 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1241 digest_dynamic(Obj_Entry *obj, int early)
1243 const Elf_Dyn *dyn_rpath;
1244 const Elf_Dyn *dyn_soname;
1245 const Elf_Dyn *dyn_runpath;
1247 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1248 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1252 * Process a shared object's program header. This is used only for the
1253 * main program, when the kernel has already loaded the main program
1254 * into memory before calling the dynamic linker. It creates and
1255 * returns an Obj_Entry structure.
1258 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1261 const Elf_Phdr *phlimit = phdr + phnum;
1263 Elf_Addr note_start, note_end;
1267 for (ph = phdr; ph < phlimit; ph++) {
1268 if (ph->p_type != PT_PHDR)
1272 obj->phsize = ph->p_memsz;
1273 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1277 obj->stack_flags = PF_X | PF_R | PF_W;
1279 for (ph = phdr; ph < phlimit; ph++) {
1280 switch (ph->p_type) {
1283 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1287 if (nsegs == 0) { /* First load segment */
1288 obj->vaddrbase = trunc_page(ph->p_vaddr);
1289 obj->mapbase = obj->vaddrbase + obj->relocbase;
1290 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1292 } else { /* Last load segment */
1293 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1300 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1305 obj->tlssize = ph->p_memsz;
1306 obj->tlsalign = ph->p_align;
1307 obj->tlsinitsize = ph->p_filesz;
1308 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1312 obj->stack_flags = ph->p_flags;
1316 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1317 obj->relro_size = round_page(ph->p_memsz);
1321 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1322 note_end = note_start + ph->p_filesz;
1323 digest_notes(obj, note_start, note_end);
1328 _rtld_error("%s: too few PT_LOAD segments", path);
1337 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1339 const Elf_Note *note;
1340 const char *note_name;
1343 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1344 note = (const Elf_Note *)((const char *)(note + 1) +
1345 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1346 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1347 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1348 note->n_descsz != sizeof(int32_t))
1350 if (note->n_type != ABI_NOTETYPE &&
1351 note->n_type != CRT_NOINIT_NOTETYPE)
1353 note_name = (const char *)(note + 1);
1354 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1355 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1357 switch (note->n_type) {
1359 /* FreeBSD osrel note */
1360 p = (uintptr_t)(note + 1);
1361 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1362 obj->osrel = *(const int32_t *)(p);
1363 dbg("note osrel %d", obj->osrel);
1365 case CRT_NOINIT_NOTETYPE:
1366 /* FreeBSD 'crt does not call init' note */
1367 obj->crt_no_init = true;
1368 dbg("note crt_no_init");
1375 dlcheck(void *handle)
1379 TAILQ_FOREACH(obj, &obj_list, next) {
1380 if (obj == (Obj_Entry *) handle)
1384 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1385 _rtld_error("Invalid shared object handle %p", handle);
1392 * If the given object is already in the donelist, return true. Otherwise
1393 * add the object to the list and return false.
1396 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1400 for (i = 0; i < dlp->num_used; i++)
1401 if (dlp->objs[i] == obj)
1404 * Our donelist allocation should always be sufficient. But if
1405 * our threads locking isn't working properly, more shared objects
1406 * could have been loaded since we allocated the list. That should
1407 * never happen, but we'll handle it properly just in case it does.
1409 if (dlp->num_used < dlp->num_alloc)
1410 dlp->objs[dlp->num_used++] = obj;
1415 * Hash function for symbol table lookup. Don't even think about changing
1416 * this. It is specified by the System V ABI.
1419 elf_hash(const char *name)
1421 const unsigned char *p = (const unsigned char *) name;
1422 unsigned long h = 0;
1425 while (*p != '\0') {
1426 h = (h << 4) + *p++;
1427 if ((g = h & 0xf0000000) != 0)
1435 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1436 * unsigned in case it's implemented with a wider type.
1439 gnu_hash(const char *s)
1445 for (c = *s; c != '\0'; c = *++s)
1447 return (h & 0xffffffff);
1451 * Find the library with the given name, and return its full pathname.
1452 * The returned string is dynamically allocated. Generates an error
1453 * message and returns NULL if the library cannot be found.
1455 * If the second argument is non-NULL, then it refers to an already-
1456 * loaded shared object, whose library search path will be searched.
1458 * The search order is:
1459 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1460 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1462 * DT_RUNPATH in the referencing file
1463 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1465 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1467 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1470 find_library(const char *xname, const Obj_Entry *refobj)
1474 bool nodeflib, objgiven;
1476 objgiven = refobj != NULL;
1477 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1478 if (xname[0] != '/' && !trust) {
1479 _rtld_error("Absolute pathname required for shared object \"%s\"",
1483 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1484 __DECONST(char *, xname)));
1487 if (libmap_disable || !objgiven ||
1488 (name = lm_find(refobj->path, xname)) == NULL)
1489 name = (char *)xname;
1491 dbg(" Searching for \"%s\"", name);
1494 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1495 * back to pre-conforming behaviour if user requested so with
1496 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1499 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1500 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1502 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1503 (pathname = search_library_path(name, gethints(false))) != NULL ||
1504 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1507 nodeflib = objgiven ? refobj->z_nodeflib : false;
1509 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1510 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1511 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1512 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1514 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1515 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1516 (objgiven && !nodeflib &&
1517 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1521 if (objgiven && refobj->path != NULL) {
1522 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1523 name, basename(refobj->path));
1525 _rtld_error("Shared object \"%s\" not found", name);
1531 * Given a symbol number in a referencing object, find the corresponding
1532 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1533 * no definition was found. Returns a pointer to the Obj_Entry of the
1534 * defining object via the reference parameter DEFOBJ_OUT.
1537 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1538 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1539 RtldLockState *lockstate)
1543 const Obj_Entry *defobj;
1549 * If we have already found this symbol, get the information from
1552 if (symnum >= refobj->dynsymcount)
1553 return NULL; /* Bad object */
1554 if (cache != NULL && cache[symnum].sym != NULL) {
1555 *defobj_out = cache[symnum].obj;
1556 return cache[symnum].sym;
1559 ref = refobj->symtab + symnum;
1560 name = refobj->strtab + ref->st_name;
1565 * We don't have to do a full scale lookup if the symbol is local.
1566 * We know it will bind to the instance in this load module; to
1567 * which we already have a pointer (ie ref). By not doing a lookup,
1568 * we not only improve performance, but it also avoids unresolvable
1569 * symbols when local symbols are not in the hash table. This has
1570 * been seen with the ia64 toolchain.
1572 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1573 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1574 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1577 symlook_init(&req, name);
1579 req.ventry = fetch_ventry(refobj, symnum);
1580 req.lockstate = lockstate;
1581 res = symlook_default(&req, refobj);
1584 defobj = req.defobj_out;
1592 * If we found no definition and the reference is weak, treat the
1593 * symbol as having the value zero.
1595 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1601 *defobj_out = defobj;
1602 /* Record the information in the cache to avoid subsequent lookups. */
1603 if (cache != NULL) {
1604 cache[symnum].sym = def;
1605 cache[symnum].obj = defobj;
1608 if (refobj != &obj_rtld)
1609 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1615 * Return the search path from the ldconfig hints file, reading it if
1616 * necessary. If nostdlib is true, then the default search paths are
1617 * not added to result.
1619 * Returns NULL if there are problems with the hints file,
1620 * or if the search path there is empty.
1623 gethints(bool nostdlib)
1625 static char *hints, *filtered_path;
1626 static struct elfhints_hdr hdr;
1627 struct fill_search_info_args sargs, hargs;
1628 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1629 struct dl_serpath *SLPpath, *hintpath;
1631 struct stat hint_stat;
1632 unsigned int SLPndx, hintndx, fndx, fcount;
1638 /* First call, read the hints file */
1639 if (hints == NULL) {
1640 /* Keep from trying again in case the hints file is bad. */
1643 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1647 * Check of hdr.dirlistlen value against type limit
1648 * intends to pacify static analyzers. Further
1649 * paranoia leads to checks that dirlist is fully
1650 * contained in the file range.
1652 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1653 hdr.magic != ELFHINTS_MAGIC ||
1654 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1655 fstat(fd, &hint_stat) == -1) {
1662 if (dl + hdr.dirlist < dl)
1665 if (dl + hdr.dirlistlen < dl)
1667 dl += hdr.dirlistlen;
1668 if (dl > hint_stat.st_size)
1670 p = xmalloc(hdr.dirlistlen + 1);
1672 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1673 read(fd, p, hdr.dirlistlen + 1) !=
1674 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') {
1683 * If caller agreed to receive list which includes the default
1684 * paths, we are done. Otherwise, if we still did not
1685 * calculated filtered result, do it now.
1688 return (hints[0] != '\0' ? hints : NULL);
1689 if (filtered_path != NULL)
1693 * Obtain the list of all configured search paths, and the
1694 * list of the default paths.
1696 * First estimate the size of the results.
1698 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1700 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1703 sargs.request = RTLD_DI_SERINFOSIZE;
1704 sargs.serinfo = &smeta;
1705 hargs.request = RTLD_DI_SERINFOSIZE;
1706 hargs.serinfo = &hmeta;
1708 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1709 path_enumerate(hints, fill_search_info, &hargs);
1711 SLPinfo = xmalloc(smeta.dls_size);
1712 hintinfo = xmalloc(hmeta.dls_size);
1715 * Next fetch both sets of paths.
1717 sargs.request = RTLD_DI_SERINFO;
1718 sargs.serinfo = SLPinfo;
1719 sargs.serpath = &SLPinfo->dls_serpath[0];
1720 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1722 hargs.request = RTLD_DI_SERINFO;
1723 hargs.serinfo = hintinfo;
1724 hargs.serpath = &hintinfo->dls_serpath[0];
1725 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1727 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1728 path_enumerate(hints, fill_search_info, &hargs);
1731 * Now calculate the difference between two sets, by excluding
1732 * standard paths from the full set.
1736 filtered_path = xmalloc(hdr.dirlistlen + 1);
1737 hintpath = &hintinfo->dls_serpath[0];
1738 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1740 SLPpath = &SLPinfo->dls_serpath[0];
1742 * Check each standard path against current.
1744 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1745 /* matched, skip the path */
1746 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1754 * Not matched against any standard path, add the path
1755 * to result. Separate consequtive paths with ':'.
1758 filtered_path[fndx] = ':';
1762 flen = strlen(hintpath->dls_name);
1763 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1766 filtered_path[fndx] = '\0';
1772 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1776 init_dag(Obj_Entry *root)
1778 const Needed_Entry *needed;
1779 const Objlist_Entry *elm;
1782 if (root->dag_inited)
1784 donelist_init(&donelist);
1786 /* Root object belongs to own DAG. */
1787 objlist_push_tail(&root->dldags, root);
1788 objlist_push_tail(&root->dagmembers, root);
1789 donelist_check(&donelist, root);
1792 * Add dependencies of root object to DAG in breadth order
1793 * by exploiting the fact that each new object get added
1794 * to the tail of the dagmembers list.
1796 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1797 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1798 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1800 objlist_push_tail(&needed->obj->dldags, root);
1801 objlist_push_tail(&root->dagmembers, needed->obj);
1804 root->dag_inited = true;
1808 globallist_curr(const Obj_Entry *obj)
1815 return (__DECONST(Obj_Entry *, obj));
1816 obj = TAILQ_PREV(obj, obj_entry_q, next);
1821 globallist_next(const Obj_Entry *obj)
1825 obj = TAILQ_NEXT(obj, next);
1829 return (__DECONST(Obj_Entry *, obj));
1834 process_z(Obj_Entry *root)
1836 const Objlist_Entry *elm;
1840 * Walk over object DAG and process every dependent object
1841 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
1842 * to grow their own DAG.
1844 * For DF_1_GLOBAL, DAG is required for symbol lookups in
1845 * symlook_global() to work.
1847 * For DF_1_NODELETE, the DAG should have its reference upped.
1849 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1853 if (obj->z_nodelete && !obj->ref_nodel) {
1854 dbg("obj %s -z nodelete", obj->path);
1857 obj->ref_nodel = true;
1859 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
1860 dbg("obj %s -z global", obj->path);
1861 objlist_push_tail(&list_global, obj);
1867 * Initialize the dynamic linker. The argument is the address at which
1868 * the dynamic linker has been mapped into memory. The primary task of
1869 * this function is to relocate the dynamic linker.
1872 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1874 Obj_Entry objtmp; /* Temporary rtld object */
1875 const Elf_Dyn *dyn_rpath;
1876 const Elf_Dyn *dyn_soname;
1877 const Elf_Dyn *dyn_runpath;
1879 #ifdef RTLD_INIT_PAGESIZES_EARLY
1880 /* The page size is required by the dynamic memory allocator. */
1881 init_pagesizes(aux_info);
1885 * Conjure up an Obj_Entry structure for the dynamic linker.
1887 * The "path" member can't be initialized yet because string constants
1888 * cannot yet be accessed. Below we will set it correctly.
1890 memset(&objtmp, 0, sizeof(objtmp));
1893 objtmp.mapbase = mapbase;
1895 objtmp.relocbase = mapbase;
1897 if (RTLD_IS_DYNAMIC()) {
1898 objtmp.dynamic = rtld_dynamic(&objtmp);
1899 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1900 assert(objtmp.needed == NULL);
1901 #if !defined(__mips__)
1902 /* MIPS has a bogus DT_TEXTREL. */
1903 assert(!objtmp.textrel);
1907 * Temporarily put the dynamic linker entry into the object list, so
1908 * that symbols can be found.
1911 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1914 /* Initialize the object list. */
1915 TAILQ_INIT(&obj_list);
1917 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1918 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1920 #ifndef RTLD_INIT_PAGESIZES_EARLY
1921 /* The page size is required by the dynamic memory allocator. */
1922 init_pagesizes(aux_info);
1925 if (aux_info[AT_OSRELDATE] != NULL)
1926 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1928 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1930 /* Replace the path with a dynamically allocated copy. */
1931 obj_rtld.path = xstrdup(PATH_RTLD);
1933 r_debug.r_brk = r_debug_state;
1934 r_debug.r_state = RT_CONSISTENT;
1938 * Retrieve the array of supported page sizes. The kernel provides the page
1939 * sizes in increasing order.
1942 init_pagesizes(Elf_Auxinfo **aux_info)
1944 static size_t psa[MAXPAGESIZES];
1948 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1950 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1951 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1954 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1957 /* As a fallback, retrieve the base page size. */
1958 size = sizeof(psa[0]);
1959 if (aux_info[AT_PAGESZ] != NULL) {
1960 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1964 mib[1] = HW_PAGESIZE;
1968 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1969 _rtld_error("sysctl for hw.pagesize(s) failed");
1975 npagesizes = size / sizeof(pagesizes[0]);
1976 /* Discard any invalid entries at the end of the array. */
1977 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1982 * Add the init functions from a needed object list (and its recursive
1983 * needed objects) to "list". This is not used directly; it is a helper
1984 * function for initlist_add_objects(). The write lock must be held
1985 * when this function is called.
1988 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1990 /* Recursively process the successor needed objects. */
1991 if (needed->next != NULL)
1992 initlist_add_neededs(needed->next, list);
1994 /* Process the current needed object. */
1995 if (needed->obj != NULL)
1996 initlist_add_objects(needed->obj, needed->obj, list);
2000 * Scan all of the DAGs rooted in the range of objects from "obj" to
2001 * "tail" and add their init functions to "list". This recurses over
2002 * the DAGs and ensure the proper init ordering such that each object's
2003 * needed libraries are initialized before the object itself. At the
2004 * same time, this function adds the objects to the global finalization
2005 * list "list_fini" in the opposite order. The write lock must be
2006 * held when this function is called.
2009 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2013 if (obj->init_scanned || obj->init_done)
2015 obj->init_scanned = true;
2017 /* Recursively process the successor objects. */
2018 nobj = globallist_next(obj);
2019 if (nobj != NULL && obj != tail)
2020 initlist_add_objects(nobj, tail, list);
2022 /* Recursively process the needed objects. */
2023 if (obj->needed != NULL)
2024 initlist_add_neededs(obj->needed, list);
2025 if (obj->needed_filtees != NULL)
2026 initlist_add_neededs(obj->needed_filtees, list);
2027 if (obj->needed_aux_filtees != NULL)
2028 initlist_add_neededs(obj->needed_aux_filtees, list);
2030 /* Add the object to the init list. */
2031 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
2032 obj->init_array != (Elf_Addr)NULL)
2033 objlist_push_tail(list, obj);
2035 /* Add the object to the global fini list in the reverse order. */
2036 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2037 && !obj->on_fini_list) {
2038 objlist_push_head(&list_fini, obj);
2039 obj->on_fini_list = true;
2044 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2048 free_needed_filtees(Needed_Entry *n)
2050 Needed_Entry *needed, *needed1;
2052 for (needed = n; needed != NULL; needed = needed->next) {
2053 if (needed->obj != NULL) {
2054 dlclose(needed->obj);
2058 for (needed = n; needed != NULL; needed = needed1) {
2059 needed1 = needed->next;
2065 unload_filtees(Obj_Entry *obj)
2068 free_needed_filtees(obj->needed_filtees);
2069 obj->needed_filtees = NULL;
2070 free_needed_filtees(obj->needed_aux_filtees);
2071 obj->needed_aux_filtees = NULL;
2072 obj->filtees_loaded = false;
2076 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2077 RtldLockState *lockstate)
2080 for (; needed != NULL; needed = needed->next) {
2081 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2082 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2083 RTLD_LOCAL, lockstate);
2088 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2091 lock_restart_for_upgrade(lockstate);
2092 if (!obj->filtees_loaded) {
2093 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2094 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2095 obj->filtees_loaded = true;
2100 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2104 for (; needed != NULL; needed = needed->next) {
2105 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2106 flags & ~RTLD_LO_NOLOAD);
2107 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2114 * Given a shared object, traverse its list of needed objects, and load
2115 * each of them. Returns 0 on success. Generates an error message and
2116 * returns -1 on failure.
2119 load_needed_objects(Obj_Entry *first, int flags)
2124 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
2127 if (process_needed(obj, obj->needed, flags) == -1)
2134 load_preload_objects(void)
2136 char *p = ld_preload;
2138 static const char delim[] = " \t:;";
2143 p += strspn(p, delim);
2144 while (*p != '\0') {
2145 size_t len = strcspn(p, delim);
2150 obj = load_object(p, -1, NULL, 0);
2152 return -1; /* XXX - cleanup */
2153 obj->z_interpose = true;
2156 p += strspn(p, delim);
2158 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2163 printable_path(const char *path)
2166 return (path == NULL ? "<unknown>" : path);
2170 * Load a shared object into memory, if it is not already loaded. The
2171 * object may be specified by name or by user-supplied file descriptor
2172 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2175 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2179 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2187 TAILQ_FOREACH(obj, &obj_list, next) {
2190 if (object_match_name(obj, name))
2194 path = find_library(name, refobj);
2201 * If we didn't find a match by pathname, or the name is not
2202 * supplied, open the file and check again by device and inode.
2203 * This avoids false mismatches caused by multiple links or ".."
2206 * To avoid a race, we open the file and use fstat() rather than
2211 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2212 _rtld_error("Cannot open \"%s\"", path);
2217 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2219 _rtld_error("Cannot dup fd");
2224 if (fstat(fd, &sb) == -1) {
2225 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2230 TAILQ_FOREACH(obj, &obj_list, next) {
2233 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2236 if (obj != NULL && name != NULL) {
2237 object_add_name(obj, name);
2242 if (flags & RTLD_LO_NOLOAD) {
2248 /* First use of this object, so we must map it in */
2249 obj = do_load_object(fd, name, path, &sb, flags);
2258 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2265 * but first, make sure that environment variables haven't been
2266 * used to circumvent the noexec flag on a filesystem.
2268 if (dangerous_ld_env) {
2269 if (fstatfs(fd, &fs) != 0) {
2270 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2273 if (fs.f_flags & MNT_NOEXEC) {
2274 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2278 dbg("loading \"%s\"", printable_path(path));
2279 obj = map_object(fd, printable_path(path), sbp);
2284 * If DT_SONAME is present in the object, digest_dynamic2 already
2285 * added it to the object names.
2288 object_add_name(obj, name);
2290 digest_dynamic(obj, 0);
2291 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2292 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2293 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2295 dbg("refusing to load non-loadable \"%s\"", obj->path);
2296 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2297 munmap(obj->mapbase, obj->mapsize);
2302 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2303 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2306 linkmap_add(obj); /* for GDB & dlinfo() */
2307 max_stack_flags |= obj->stack_flags;
2309 dbg(" %p .. %p: %s", obj->mapbase,
2310 obj->mapbase + obj->mapsize - 1, obj->path);
2312 dbg(" WARNING: %s has impure text", obj->path);
2313 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2320 obj_from_addr(const void *addr)
2324 TAILQ_FOREACH(obj, &obj_list, next) {
2327 if (addr < (void *) obj->mapbase)
2329 if (addr < (void *) (obj->mapbase + obj->mapsize))
2338 Elf_Addr *preinit_addr;
2341 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2342 if (preinit_addr == NULL)
2345 for (index = 0; index < obj_main->preinit_array_num; index++) {
2346 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2347 dbg("calling preinit function for %s at %p", obj_main->path,
2348 (void *)preinit_addr[index]);
2349 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2350 0, 0, obj_main->path);
2351 call_init_pointer(obj_main, preinit_addr[index]);
2357 * Call the finalization functions for each of the objects in "list"
2358 * belonging to the DAG of "root" and referenced once. If NULL "root"
2359 * is specified, every finalization function will be called regardless
2360 * of the reference count and the list elements won't be freed. All of
2361 * the objects are expected to have non-NULL fini functions.
2364 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2368 Elf_Addr *fini_addr;
2371 assert(root == NULL || root->refcount == 1);
2374 * Preserve the current error message since a fini function might
2375 * call into the dynamic linker and overwrite it.
2377 saved_msg = errmsg_save();
2379 STAILQ_FOREACH(elm, list, link) {
2380 if (root != NULL && (elm->obj->refcount != 1 ||
2381 objlist_find(&root->dagmembers, elm->obj) == NULL))
2383 /* Remove object from fini list to prevent recursive invocation. */
2384 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2386 * XXX: If a dlopen() call references an object while the
2387 * fini function is in progress, we might end up trying to
2388 * unload the referenced object in dlclose() or the object
2389 * won't be unloaded although its fini function has been
2392 lock_release(rtld_bind_lock, lockstate);
2395 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2396 * When this happens, DT_FINI_ARRAY is processed first.
2398 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2399 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2400 for (index = elm->obj->fini_array_num - 1; index >= 0;
2402 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2403 dbg("calling fini function for %s at %p",
2404 elm->obj->path, (void *)fini_addr[index]);
2405 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2406 (void *)fini_addr[index], 0, 0, elm->obj->path);
2407 call_initfini_pointer(elm->obj, fini_addr[index]);
2411 if (elm->obj->fini != (Elf_Addr)NULL) {
2412 dbg("calling fini function for %s at %p", elm->obj->path,
2413 (void *)elm->obj->fini);
2414 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2415 0, 0, elm->obj->path);
2416 call_initfini_pointer(elm->obj, elm->obj->fini);
2418 wlock_acquire(rtld_bind_lock, lockstate);
2419 /* No need to free anything if process is going down. */
2423 * We must restart the list traversal after every fini call
2424 * because a dlclose() call from the fini function or from
2425 * another thread might have modified the reference counts.
2429 } while (elm != NULL);
2430 errmsg_restore(saved_msg);
2434 * Call the initialization functions for each of the objects in
2435 * "list". All of the objects are expected to have non-NULL init
2439 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2444 Elf_Addr *init_addr;
2448 * Clean init_scanned flag so that objects can be rechecked and
2449 * possibly initialized earlier if any of vectors called below
2450 * cause the change by using dlopen.
2452 TAILQ_FOREACH(obj, &obj_list, next) {
2455 obj->init_scanned = false;
2459 * Preserve the current error message since an init function might
2460 * call into the dynamic linker and overwrite it.
2462 saved_msg = errmsg_save();
2463 STAILQ_FOREACH(elm, list, link) {
2464 if (elm->obj->init_done) /* Initialized early. */
2467 * Race: other thread might try to use this object before current
2468 * one completes the initilization. Not much can be done here
2469 * without better locking.
2471 elm->obj->init_done = true;
2472 lock_release(rtld_bind_lock, lockstate);
2475 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2476 * When this happens, DT_INIT is processed first.
2478 if (elm->obj->init != (Elf_Addr)NULL) {
2479 dbg("calling init function for %s at %p", elm->obj->path,
2480 (void *)elm->obj->init);
2481 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2482 0, 0, elm->obj->path);
2483 call_initfini_pointer(elm->obj, elm->obj->init);
2485 init_addr = (Elf_Addr *)elm->obj->init_array;
2486 if (init_addr != NULL) {
2487 for (index = 0; index < elm->obj->init_array_num; index++) {
2488 if (init_addr[index] != 0 && init_addr[index] != 1) {
2489 dbg("calling init function for %s at %p", elm->obj->path,
2490 (void *)init_addr[index]);
2491 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2492 (void *)init_addr[index], 0, 0, elm->obj->path);
2493 call_init_pointer(elm->obj, init_addr[index]);
2497 wlock_acquire(rtld_bind_lock, lockstate);
2499 errmsg_restore(saved_msg);
2503 objlist_clear(Objlist *list)
2507 while (!STAILQ_EMPTY(list)) {
2508 elm = STAILQ_FIRST(list);
2509 STAILQ_REMOVE_HEAD(list, link);
2514 static Objlist_Entry *
2515 objlist_find(Objlist *list, const Obj_Entry *obj)
2519 STAILQ_FOREACH(elm, list, link)
2520 if (elm->obj == obj)
2526 objlist_init(Objlist *list)
2532 objlist_push_head(Objlist *list, Obj_Entry *obj)
2536 elm = NEW(Objlist_Entry);
2538 STAILQ_INSERT_HEAD(list, elm, link);
2542 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2546 elm = NEW(Objlist_Entry);
2548 STAILQ_INSERT_TAIL(list, elm, link);
2552 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2554 Objlist_Entry *elm, *listelm;
2556 STAILQ_FOREACH(listelm, list, link) {
2557 if (listelm->obj == listobj)
2560 elm = NEW(Objlist_Entry);
2562 if (listelm != NULL)
2563 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2565 STAILQ_INSERT_TAIL(list, elm, link);
2569 objlist_remove(Objlist *list, Obj_Entry *obj)
2573 if ((elm = objlist_find(list, obj)) != NULL) {
2574 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2580 * Relocate dag rooted in the specified object.
2581 * Returns 0 on success, or -1 on failure.
2585 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2586 int flags, RtldLockState *lockstate)
2592 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2593 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2602 * Prepare for, or clean after, relocating an object marked with
2603 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2604 * segments are remapped read-write. After relocations are done, the
2605 * segment's permissions are returned back to the modes specified in
2606 * the phdrs. If any relocation happened, or always for wired
2607 * program, COW is triggered.
2610 reloc_textrel_prot(Obj_Entry *obj, bool before)
2617 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2619 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2621 base = obj->relocbase + trunc_page(ph->p_vaddr);
2622 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2623 trunc_page(ph->p_vaddr);
2624 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2625 if (mprotect(base, sz, prot) == -1) {
2626 _rtld_error("%s: Cannot write-%sable text segment: %s",
2627 obj->path, before ? "en" : "dis",
2628 rtld_strerror(errno));
2636 * Relocate single object.
2637 * Returns 0 on success, or -1 on failure.
2640 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2641 int flags, RtldLockState *lockstate)
2646 obj->relocated = true;
2648 dbg("relocating \"%s\"", obj->path);
2650 if (obj->symtab == NULL || obj->strtab == NULL ||
2651 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2652 _rtld_error("%s: Shared object has no run-time symbol table",
2657 /* There are relocations to the write-protected text segment. */
2658 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2661 /* Process the non-PLT non-IFUNC relocations. */
2662 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2665 /* Re-protected the text segment. */
2666 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2669 /* Set the special PLT or GOT entries. */
2672 /* Process the PLT relocations. */
2673 if (reloc_plt(obj) == -1)
2675 /* Relocate the jump slots if we are doing immediate binding. */
2676 if (obj->bind_now || bind_now)
2677 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2681 * Process the non-PLT IFUNC relocations. The relocations are
2682 * processed in two phases, because IFUNC resolvers may
2683 * reference other symbols, which must be readily processed
2684 * before resolvers are called.
2686 if (obj->non_plt_gnu_ifunc &&
2687 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2690 if (obj->relro_size > 0) {
2691 if (mprotect(obj->relro_page, obj->relro_size,
2693 _rtld_error("%s: Cannot enforce relro protection: %s",
2694 obj->path, rtld_strerror(errno));
2700 * Set up the magic number and version in the Obj_Entry. These
2701 * were checked in the crt1.o from the original ElfKit, so we
2702 * set them for backward compatibility.
2704 obj->magic = RTLD_MAGIC;
2705 obj->version = RTLD_VERSION;
2711 * Relocate newly-loaded shared objects. The argument is a pointer to
2712 * the Obj_Entry for the first such object. All objects from the first
2713 * to the end of the list of objects are relocated. Returns 0 on success,
2717 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2718 int flags, RtldLockState *lockstate)
2725 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
2728 error = relocate_object(obj, bind_now, rtldobj, flags,
2737 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2738 * referencing STT_GNU_IFUNC symbols is postponed till the other
2739 * relocations are done. The indirect functions specified as
2740 * ifunc are allowed to call other symbols, so we need to have
2741 * objects relocated before asking for resolution from indirects.
2743 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2744 * instead of the usual lazy handling of PLT slots. It is
2745 * consistent with how GNU does it.
2748 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2749 RtldLockState *lockstate)
2751 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2753 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2754 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2760 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2761 RtldLockState *lockstate)
2766 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
2769 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2776 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2777 RtldLockState *lockstate)
2781 STAILQ_FOREACH(elm, list, link) {
2782 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2790 * Cleanup procedure. It will be called (by the atexit mechanism) just
2791 * before the process exits.
2796 RtldLockState lockstate;
2798 wlock_acquire(rtld_bind_lock, &lockstate);
2800 objlist_call_fini(&list_fini, NULL, &lockstate);
2801 /* No need to remove the items from the list, since we are exiting. */
2802 if (!libmap_disable)
2804 lock_release(rtld_bind_lock, &lockstate);
2808 * Iterate over a search path, translate each element, and invoke the
2809 * callback on the result.
2812 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2818 path += strspn(path, ":;");
2819 while (*path != '\0') {
2823 len = strcspn(path, ":;");
2824 trans = lm_findn(NULL, path, len);
2826 res = callback(trans, strlen(trans), arg);
2828 res = callback(path, len, arg);
2834 path += strspn(path, ":;");
2840 struct try_library_args {
2848 try_library_path(const char *dir, size_t dirlen, void *param)
2850 struct try_library_args *arg;
2853 if (*dir == '/' || trust) {
2856 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2859 pathname = arg->buffer;
2860 strncpy(pathname, dir, dirlen);
2861 pathname[dirlen] = '/';
2862 strcpy(pathname + dirlen + 1, arg->name);
2864 dbg(" Trying \"%s\"", pathname);
2865 if (access(pathname, F_OK) == 0) { /* We found it */
2866 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2867 strcpy(pathname, arg->buffer);
2875 search_library_path(const char *name, const char *path)
2878 struct try_library_args arg;
2884 arg.namelen = strlen(name);
2885 arg.buffer = xmalloc(PATH_MAX);
2886 arg.buflen = PATH_MAX;
2888 p = path_enumerate(path, try_library_path, &arg);
2896 dlclose(void *handle)
2899 RtldLockState lockstate;
2901 wlock_acquire(rtld_bind_lock, &lockstate);
2902 root = dlcheck(handle);
2904 lock_release(rtld_bind_lock, &lockstate);
2907 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2910 /* Unreference the object and its dependencies. */
2911 root->dl_refcount--;
2913 if (root->refcount == 1) {
2915 * The object will be no longer referenced, so we must unload it.
2916 * First, call the fini functions.
2918 objlist_call_fini(&list_fini, root, &lockstate);
2922 /* Finish cleaning up the newly-unreferenced objects. */
2923 GDB_STATE(RT_DELETE,&root->linkmap);
2924 unload_object(root);
2925 GDB_STATE(RT_CONSISTENT,NULL);
2929 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2930 lock_release(rtld_bind_lock, &lockstate);
2937 char *msg = error_message;
2938 error_message = NULL;
2943 * This function is deprecated and has no effect.
2946 dllockinit(void *context,
2947 void *(*lock_create)(void *context),
2948 void (*rlock_acquire)(void *lock),
2949 void (*wlock_acquire)(void *lock),
2950 void (*lock_release)(void *lock),
2951 void (*lock_destroy)(void *lock),
2952 void (*context_destroy)(void *context))
2954 static void *cur_context;
2955 static void (*cur_context_destroy)(void *);
2957 /* Just destroy the context from the previous call, if necessary. */
2958 if (cur_context_destroy != NULL)
2959 cur_context_destroy(cur_context);
2960 cur_context = context;
2961 cur_context_destroy = context_destroy;
2965 dlopen(const char *name, int mode)
2968 return (rtld_dlopen(name, -1, mode));
2972 fdlopen(int fd, int mode)
2975 return (rtld_dlopen(NULL, fd, mode));
2979 rtld_dlopen(const char *name, int fd, int mode)
2981 RtldLockState lockstate;
2984 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2985 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2986 if (ld_tracing != NULL) {
2987 rlock_acquire(rtld_bind_lock, &lockstate);
2988 if (sigsetjmp(lockstate.env, 0) != 0)
2989 lock_upgrade(rtld_bind_lock, &lockstate);
2990 environ = (char **)*get_program_var_addr("environ", &lockstate);
2991 lock_release(rtld_bind_lock, &lockstate);
2993 lo_flags = RTLD_LO_DLOPEN;
2994 if (mode & RTLD_NODELETE)
2995 lo_flags |= RTLD_LO_NODELETE;
2996 if (mode & RTLD_NOLOAD)
2997 lo_flags |= RTLD_LO_NOLOAD;
2998 if (ld_tracing != NULL)
2999 lo_flags |= RTLD_LO_TRACE;
3001 return (dlopen_object(name, fd, obj_main, lo_flags,
3002 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3006 dlopen_cleanup(Obj_Entry *obj)
3011 if (obj->refcount == 0)
3016 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3017 int mode, RtldLockState *lockstate)
3019 Obj_Entry *old_obj_tail;
3022 RtldLockState mlockstate;
3025 objlist_init(&initlist);
3027 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3028 wlock_acquire(rtld_bind_lock, &mlockstate);
3029 lockstate = &mlockstate;
3031 GDB_STATE(RT_ADD,NULL);
3033 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3035 if (name == NULL && fd == -1) {
3039 obj = load_object(name, fd, refobj, lo_flags);
3044 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3045 objlist_push_tail(&list_global, obj);
3046 if (globallist_next(old_obj_tail) != NULL) {
3047 /* We loaded something new. */
3048 assert(globallist_next(old_obj_tail) == obj);
3049 result = load_needed_objects(obj,
3050 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3054 result = rtld_verify_versions(&obj->dagmembers);
3055 if (result != -1 && ld_tracing)
3057 if (result == -1 || relocate_object_dag(obj,
3058 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3059 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3061 dlopen_cleanup(obj);
3063 } else if (lo_flags & RTLD_LO_EARLY) {
3065 * Do not call the init functions for early loaded
3066 * filtees. The image is still not initialized enough
3069 * Our object is found by the global object list and
3070 * will be ordered among all init calls done right
3071 * before transferring control to main.
3074 /* Make list of init functions to call. */
3075 initlist_add_objects(obj, obj, &initlist);
3078 * Process all no_delete or global objects here, given
3079 * them own DAGs to prevent their dependencies from being
3080 * unloaded. This has to be done after we have loaded all
3081 * of the dependencies, so that we do not miss any.
3087 * Bump the reference counts for objects on this DAG. If
3088 * this is the first dlopen() call for the object that was
3089 * already loaded as a dependency, initialize the dag
3095 if ((lo_flags & RTLD_LO_TRACE) != 0)
3098 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3099 obj->z_nodelete) && !obj->ref_nodel) {
3100 dbg("obj %s nodelete", obj->path);
3102 obj->z_nodelete = obj->ref_nodel = true;
3106 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3108 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3110 if (!(lo_flags & RTLD_LO_EARLY)) {
3111 map_stacks_exec(lockstate);
3114 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3115 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3117 objlist_clear(&initlist);
3118 dlopen_cleanup(obj);
3119 if (lockstate == &mlockstate)
3120 lock_release(rtld_bind_lock, lockstate);
3124 if (!(lo_flags & RTLD_LO_EARLY)) {
3125 /* Call the init functions. */
3126 objlist_call_init(&initlist, lockstate);
3128 objlist_clear(&initlist);
3129 if (lockstate == &mlockstate)
3130 lock_release(rtld_bind_lock, lockstate);
3133 trace_loaded_objects(obj);
3134 if (lockstate == &mlockstate)
3135 lock_release(rtld_bind_lock, lockstate);
3140 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3144 const Obj_Entry *obj, *defobj;
3147 RtldLockState lockstate;
3156 symlook_init(&req, name);
3158 req.flags = flags | SYMLOOK_IN_PLT;
3159 req.lockstate = &lockstate;
3161 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3162 rlock_acquire(rtld_bind_lock, &lockstate);
3163 if (sigsetjmp(lockstate.env, 0) != 0)
3164 lock_upgrade(rtld_bind_lock, &lockstate);
3165 if (handle == NULL || handle == RTLD_NEXT ||
3166 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3168 if ((obj = obj_from_addr(retaddr)) == NULL) {
3169 _rtld_error("Cannot determine caller's shared object");
3170 lock_release(rtld_bind_lock, &lockstate);
3171 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3174 if (handle == NULL) { /* Just the caller's shared object. */
3175 res = symlook_obj(&req, obj);
3178 defobj = req.defobj_out;
3180 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3181 handle == RTLD_SELF) { /* ... caller included */
3182 if (handle == RTLD_NEXT)
3183 obj = globallist_next(obj);
3184 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
3187 res = symlook_obj(&req, obj);
3190 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3192 defobj = req.defobj_out;
3193 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3199 * Search the dynamic linker itself, and possibly resolve the
3200 * symbol from there. This is how the application links to
3201 * dynamic linker services such as dlopen.
3203 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3204 res = symlook_obj(&req, &obj_rtld);
3207 defobj = req.defobj_out;
3211 assert(handle == RTLD_DEFAULT);
3212 res = symlook_default(&req, obj);
3214 defobj = req.defobj_out;
3219 if ((obj = dlcheck(handle)) == NULL) {
3220 lock_release(rtld_bind_lock, &lockstate);
3221 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3225 donelist_init(&donelist);
3226 if (obj->mainprog) {
3227 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3228 res = symlook_global(&req, &donelist);
3231 defobj = req.defobj_out;
3234 * Search the dynamic linker itself, and possibly resolve the
3235 * symbol from there. This is how the application links to
3236 * dynamic linker services such as dlopen.
3238 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3239 res = symlook_obj(&req, &obj_rtld);
3242 defobj = req.defobj_out;
3247 /* Search the whole DAG rooted at the given object. */
3248 res = symlook_list(&req, &obj->dagmembers, &donelist);
3251 defobj = req.defobj_out;
3257 lock_release(rtld_bind_lock, &lockstate);
3260 * The value required by the caller is derived from the value
3261 * of the symbol. For the ia64 architecture, we need to
3262 * construct a function descriptor which the caller can use to
3263 * call the function with the right 'gp' value. For other
3264 * architectures and for non-functions, the value is simply
3265 * the relocated value of the symbol.
3267 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3268 sym = make_function_pointer(def, defobj);
3269 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3270 sym = rtld_resolve_ifunc(defobj, def);
3271 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3273 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3275 ti.ti_module = defobj->tlsindex;
3276 ti.ti_offset = def->st_value;
3277 sym = __tls_get_addr(&ti);
3280 sym = defobj->relocbase + def->st_value;
3281 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3285 _rtld_error("Undefined symbol \"%s\"", name);
3286 lock_release(rtld_bind_lock, &lockstate);
3287 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3292 dlsym(void *handle, const char *name)
3294 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3299 dlfunc(void *handle, const char *name)
3306 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3312 dlvsym(void *handle, const char *name, const char *version)
3316 ventry.name = version;
3318 ventry.hash = elf_hash(version);
3320 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3325 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3327 const Obj_Entry *obj;
3328 RtldLockState lockstate;
3330 rlock_acquire(rtld_bind_lock, &lockstate);
3331 obj = obj_from_addr(addr);
3333 _rtld_error("No shared object contains address");
3334 lock_release(rtld_bind_lock, &lockstate);
3337 rtld_fill_dl_phdr_info(obj, phdr_info);
3338 lock_release(rtld_bind_lock, &lockstate);
3343 dladdr(const void *addr, Dl_info *info)
3345 const Obj_Entry *obj;
3348 unsigned long symoffset;
3349 RtldLockState lockstate;
3351 rlock_acquire(rtld_bind_lock, &lockstate);
3352 obj = obj_from_addr(addr);
3354 _rtld_error("No shared object contains address");
3355 lock_release(rtld_bind_lock, &lockstate);
3358 info->dli_fname = obj->path;
3359 info->dli_fbase = obj->mapbase;
3360 info->dli_saddr = (void *)0;
3361 info->dli_sname = NULL;
3364 * Walk the symbol list looking for the symbol whose address is
3365 * closest to the address sent in.
3367 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3368 def = obj->symtab + symoffset;
3371 * For skip the symbol if st_shndx is either SHN_UNDEF or
3374 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3378 * If the symbol is greater than the specified address, or if it
3379 * is further away from addr than the current nearest symbol,
3382 symbol_addr = obj->relocbase + def->st_value;
3383 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3386 /* Update our idea of the nearest symbol. */
3387 info->dli_sname = obj->strtab + def->st_name;
3388 info->dli_saddr = symbol_addr;
3391 if (info->dli_saddr == addr)
3394 lock_release(rtld_bind_lock, &lockstate);
3399 dlinfo(void *handle, int request, void *p)
3401 const Obj_Entry *obj;
3402 RtldLockState lockstate;
3405 rlock_acquire(rtld_bind_lock, &lockstate);
3407 if (handle == NULL || handle == RTLD_SELF) {
3410 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3411 if ((obj = obj_from_addr(retaddr)) == NULL)
3412 _rtld_error("Cannot determine caller's shared object");
3414 obj = dlcheck(handle);
3417 lock_release(rtld_bind_lock, &lockstate);
3423 case RTLD_DI_LINKMAP:
3424 *((struct link_map const **)p) = &obj->linkmap;
3426 case RTLD_DI_ORIGIN:
3427 error = rtld_dirname(obj->path, p);
3430 case RTLD_DI_SERINFOSIZE:
3431 case RTLD_DI_SERINFO:
3432 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3436 _rtld_error("Invalid request %d passed to dlinfo()", request);
3440 lock_release(rtld_bind_lock, &lockstate);
3446 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3449 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3450 phdr_info->dlpi_name = obj->path;
3451 phdr_info->dlpi_phdr = obj->phdr;
3452 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3453 phdr_info->dlpi_tls_modid = obj->tlsindex;
3454 phdr_info->dlpi_tls_data = obj->tlsinit;
3455 phdr_info->dlpi_adds = obj_loads;
3456 phdr_info->dlpi_subs = obj_loads - obj_count;
3460 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3462 struct dl_phdr_info phdr_info;
3463 Obj_Entry *obj, marker;
3464 RtldLockState bind_lockstate, phdr_lockstate;
3467 bzero(&marker, sizeof(marker));
3468 marker.marker = true;
3471 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3472 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3473 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3474 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3475 rtld_fill_dl_phdr_info(obj, &phdr_info);
3476 lock_release(rtld_bind_lock, &bind_lockstate);
3478 error = callback(&phdr_info, sizeof phdr_info, param);
3480 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3481 obj = globallist_next(&marker);
3482 TAILQ_REMOVE(&obj_list, &marker, next);
3484 lock_release(rtld_bind_lock, &bind_lockstate);
3485 lock_release(rtld_phdr_lock, &phdr_lockstate);
3491 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3492 lock_release(rtld_bind_lock, &bind_lockstate);
3493 error = callback(&phdr_info, sizeof(phdr_info), param);
3495 lock_release(rtld_phdr_lock, &phdr_lockstate);
3500 fill_search_info(const char *dir, size_t dirlen, void *param)
3502 struct fill_search_info_args *arg;
3506 if (arg->request == RTLD_DI_SERINFOSIZE) {
3507 arg->serinfo->dls_cnt ++;
3508 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3510 struct dl_serpath *s_entry;
3512 s_entry = arg->serpath;
3513 s_entry->dls_name = arg->strspace;
3514 s_entry->dls_flags = arg->flags;
3516 strncpy(arg->strspace, dir, dirlen);
3517 arg->strspace[dirlen] = '\0';
3519 arg->strspace += dirlen + 1;
3527 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3529 struct dl_serinfo _info;
3530 struct fill_search_info_args args;
3532 args.request = RTLD_DI_SERINFOSIZE;
3533 args.serinfo = &_info;
3535 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3538 path_enumerate(obj->rpath, fill_search_info, &args);
3539 path_enumerate(ld_library_path, fill_search_info, &args);
3540 path_enumerate(obj->runpath, fill_search_info, &args);
3541 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3542 if (!obj->z_nodeflib)
3543 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3546 if (request == RTLD_DI_SERINFOSIZE) {
3547 info->dls_size = _info.dls_size;
3548 info->dls_cnt = _info.dls_cnt;
3552 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3553 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3557 args.request = RTLD_DI_SERINFO;
3558 args.serinfo = info;
3559 args.serpath = &info->dls_serpath[0];
3560 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3562 args.flags = LA_SER_RUNPATH;
3563 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3566 args.flags = LA_SER_LIBPATH;
3567 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3570 args.flags = LA_SER_RUNPATH;
3571 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3574 args.flags = LA_SER_CONFIG;
3575 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3579 args.flags = LA_SER_DEFAULT;
3580 if (!obj->z_nodeflib &&
3581 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3587 rtld_dirname(const char *path, char *bname)
3591 /* Empty or NULL string gets treated as "." */
3592 if (path == NULL || *path == '\0') {
3598 /* Strip trailing slashes */
3599 endp = path + strlen(path) - 1;
3600 while (endp > path && *endp == '/')
3603 /* Find the start of the dir */
3604 while (endp > path && *endp != '/')
3607 /* Either the dir is "/" or there are no slashes */
3609 bname[0] = *endp == '/' ? '/' : '.';
3615 } while (endp > path && *endp == '/');
3618 if (endp - path + 2 > PATH_MAX)
3620 _rtld_error("Filename is too long: %s", path);
3624 strncpy(bname, path, endp - path + 1);
3625 bname[endp - path + 1] = '\0';
3630 rtld_dirname_abs(const char *path, char *base)
3634 if (realpath(path, base) == NULL)
3636 dbg("%s -> %s", path, base);
3637 last = strrchr(base, '/');
3646 linkmap_add(Obj_Entry *obj)
3648 struct link_map *l = &obj->linkmap;
3649 struct link_map *prev;
3651 obj->linkmap.l_name = obj->path;
3652 obj->linkmap.l_addr = obj->mapbase;
3653 obj->linkmap.l_ld = obj->dynamic;
3655 /* GDB needs load offset on MIPS to use the symbols */
3656 obj->linkmap.l_offs = obj->relocbase;
3659 if (r_debug.r_map == NULL) {
3665 * Scan to the end of the list, but not past the entry for the
3666 * dynamic linker, which we want to keep at the very end.
3668 for (prev = r_debug.r_map;
3669 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3670 prev = prev->l_next)
3673 /* Link in the new entry. */
3675 l->l_next = prev->l_next;
3676 if (l->l_next != NULL)
3677 l->l_next->l_prev = l;
3682 linkmap_delete(Obj_Entry *obj)
3684 struct link_map *l = &obj->linkmap;
3686 if (l->l_prev == NULL) {
3687 if ((r_debug.r_map = l->l_next) != NULL)
3688 l->l_next->l_prev = NULL;
3692 if ((l->l_prev->l_next = l->l_next) != NULL)
3693 l->l_next->l_prev = l->l_prev;
3697 * Function for the debugger to set a breakpoint on to gain control.
3699 * The two parameters allow the debugger to easily find and determine
3700 * what the runtime loader is doing and to whom it is doing it.
3702 * When the loadhook trap is hit (r_debug_state, set at program
3703 * initialization), the arguments can be found on the stack:
3705 * +8 struct link_map *m
3706 * +4 struct r_debug *rd
3710 r_debug_state(struct r_debug* rd, struct link_map *m)
3713 * The following is a hack to force the compiler to emit calls to
3714 * this function, even when optimizing. If the function is empty,
3715 * the compiler is not obliged to emit any code for calls to it,
3716 * even when marked __noinline. However, gdb depends on those
3719 __compiler_membar();
3723 * A function called after init routines have completed. This can be used to
3724 * break before a program's entry routine is called, and can be used when
3725 * main is not available in the symbol table.
3728 _r_debug_postinit(struct link_map *m)
3731 /* See r_debug_state(). */
3732 __compiler_membar();
3736 * Get address of the pointer variable in the main program.
3737 * Prefer non-weak symbol over the weak one.
3739 static const void **
3740 get_program_var_addr(const char *name, RtldLockState *lockstate)
3745 symlook_init(&req, name);
3746 req.lockstate = lockstate;
3747 donelist_init(&donelist);
3748 if (symlook_global(&req, &donelist) != 0)
3750 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3751 return ((const void **)make_function_pointer(req.sym_out,
3753 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3754 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3756 return ((const void **)(req.defobj_out->relocbase +
3757 req.sym_out->st_value));
3761 * Set a pointer variable in the main program to the given value. This
3762 * is used to set key variables such as "environ" before any of the
3763 * init functions are called.
3766 set_program_var(const char *name, const void *value)
3770 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3771 dbg("\"%s\": *%p <-- %p", name, addr, value);
3777 * Search the global objects, including dependencies and main object,
3778 * for the given symbol.
3781 symlook_global(SymLook *req, DoneList *donelist)
3784 const Objlist_Entry *elm;
3787 symlook_init_from_req(&req1, req);
3789 /* Search all objects loaded at program start up. */
3790 if (req->defobj_out == NULL ||
3791 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3792 res = symlook_list(&req1, &list_main, donelist);
3793 if (res == 0 && (req->defobj_out == NULL ||
3794 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3795 req->sym_out = req1.sym_out;
3796 req->defobj_out = req1.defobj_out;
3797 assert(req->defobj_out != NULL);
3801 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3802 STAILQ_FOREACH(elm, &list_global, link) {
3803 if (req->defobj_out != NULL &&
3804 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3806 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3807 if (res == 0 && (req->defobj_out == NULL ||
3808 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3809 req->sym_out = req1.sym_out;
3810 req->defobj_out = req1.defobj_out;
3811 assert(req->defobj_out != NULL);
3815 return (req->sym_out != NULL ? 0 : ESRCH);
3819 * Given a symbol name in a referencing object, find the corresponding
3820 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3821 * no definition was found. Returns a pointer to the Obj_Entry of the
3822 * defining object via the reference parameter DEFOBJ_OUT.
3825 symlook_default(SymLook *req, const Obj_Entry *refobj)
3828 const Objlist_Entry *elm;
3832 donelist_init(&donelist);
3833 symlook_init_from_req(&req1, req);
3835 /* Look first in the referencing object if linked symbolically. */
3836 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3837 res = symlook_obj(&req1, refobj);
3839 req->sym_out = req1.sym_out;
3840 req->defobj_out = req1.defobj_out;
3841 assert(req->defobj_out != NULL);
3845 symlook_global(req, &donelist);
3847 /* Search all dlopened DAGs containing the referencing object. */
3848 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3849 if (req->sym_out != NULL &&
3850 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3852 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3853 if (res == 0 && (req->sym_out == NULL ||
3854 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3855 req->sym_out = req1.sym_out;
3856 req->defobj_out = req1.defobj_out;
3857 assert(req->defobj_out != NULL);
3862 * Search the dynamic linker itself, and possibly resolve the
3863 * symbol from there. This is how the application links to
3864 * dynamic linker services such as dlopen.
3866 if (req->sym_out == NULL ||
3867 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3868 res = symlook_obj(&req1, &obj_rtld);
3870 req->sym_out = req1.sym_out;
3871 req->defobj_out = req1.defobj_out;
3872 assert(req->defobj_out != NULL);
3876 return (req->sym_out != NULL ? 0 : ESRCH);
3880 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3883 const Obj_Entry *defobj;
3884 const Objlist_Entry *elm;
3890 STAILQ_FOREACH(elm, objlist, link) {
3891 if (donelist_check(dlp, elm->obj))
3893 symlook_init_from_req(&req1, req);
3894 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3895 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3897 defobj = req1.defobj_out;
3898 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3905 req->defobj_out = defobj;
3912 * Search the chain of DAGS cointed to by the given Needed_Entry
3913 * for a symbol of the given name. Each DAG is scanned completely
3914 * before advancing to the next one. Returns a pointer to the symbol,
3915 * or NULL if no definition was found.
3918 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3921 const Needed_Entry *n;
3922 const Obj_Entry *defobj;
3928 symlook_init_from_req(&req1, req);
3929 for (n = needed; n != NULL; n = n->next) {
3930 if (n->obj == NULL ||
3931 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3933 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3935 defobj = req1.defobj_out;
3936 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3942 req->defobj_out = defobj;
3949 * Search the symbol table of a single shared object for a symbol of
3950 * the given name and version, if requested. Returns a pointer to the
3951 * symbol, or NULL if no definition was found. If the object is
3952 * filter, return filtered symbol from filtee.
3954 * The symbol's hash value is passed in for efficiency reasons; that
3955 * eliminates many recomputations of the hash value.
3958 symlook_obj(SymLook *req, const Obj_Entry *obj)
3962 int flags, res, mres;
3965 * If there is at least one valid hash at this point, we prefer to
3966 * use the faster GNU version if available.
3968 if (obj->valid_hash_gnu)
3969 mres = symlook_obj1_gnu(req, obj);
3970 else if (obj->valid_hash_sysv)
3971 mres = symlook_obj1_sysv(req, obj);
3976 if (obj->needed_filtees != NULL) {
3977 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3978 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3979 donelist_init(&donelist);
3980 symlook_init_from_req(&req1, req);
3981 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3983 req->sym_out = req1.sym_out;
3984 req->defobj_out = req1.defobj_out;
3988 if (obj->needed_aux_filtees != NULL) {
3989 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3990 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3991 donelist_init(&donelist);
3992 symlook_init_from_req(&req1, req);
3993 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3995 req->sym_out = req1.sym_out;
3996 req->defobj_out = req1.defobj_out;
4004 /* Symbol match routine common to both hash functions */
4006 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4007 const unsigned long symnum)
4010 const Elf_Sym *symp;
4013 symp = obj->symtab + symnum;
4014 strp = obj->strtab + symp->st_name;
4016 switch (ELF_ST_TYPE(symp->st_info)) {
4022 if (symp->st_value == 0)
4026 if (symp->st_shndx != SHN_UNDEF)
4029 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4030 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4037 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4040 if (req->ventry == NULL) {
4041 if (obj->versyms != NULL) {
4042 verndx = VER_NDX(obj->versyms[symnum]);
4043 if (verndx > obj->vernum) {
4045 "%s: symbol %s references wrong version %d",
4046 obj->path, obj->strtab + symnum, verndx);
4050 * If we are not called from dlsym (i.e. this
4051 * is a normal relocation from unversioned
4052 * binary), accept the symbol immediately if
4053 * it happens to have first version after this
4054 * shared object became versioned. Otherwise,
4055 * if symbol is versioned and not hidden,
4056 * remember it. If it is the only symbol with
4057 * this name exported by the shared object, it
4058 * will be returned as a match by the calling
4059 * function. If symbol is global (verndx < 2)
4060 * accept it unconditionally.
4062 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4063 verndx == VER_NDX_GIVEN) {
4064 result->sym_out = symp;
4067 else if (verndx >= VER_NDX_GIVEN) {
4068 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4070 if (result->vsymp == NULL)
4071 result->vsymp = symp;
4077 result->sym_out = symp;
4080 if (obj->versyms == NULL) {
4081 if (object_match_name(obj, req->ventry->name)) {
4082 _rtld_error("%s: object %s should provide version %s "
4083 "for symbol %s", obj_rtld.path, obj->path,
4084 req->ventry->name, obj->strtab + symnum);
4088 verndx = VER_NDX(obj->versyms[symnum]);
4089 if (verndx > obj->vernum) {
4090 _rtld_error("%s: symbol %s references wrong version %d",
4091 obj->path, obj->strtab + symnum, verndx);
4094 if (obj->vertab[verndx].hash != req->ventry->hash ||
4095 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4097 * Version does not match. Look if this is a
4098 * global symbol and if it is not hidden. If
4099 * global symbol (verndx < 2) is available,
4100 * use it. Do not return symbol if we are
4101 * called by dlvsym, because dlvsym looks for
4102 * a specific version and default one is not
4103 * what dlvsym wants.
4105 if ((req->flags & SYMLOOK_DLSYM) ||
4106 (verndx >= VER_NDX_GIVEN) ||
4107 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4111 result->sym_out = symp;
4116 * Search for symbol using SysV hash function.
4117 * obj->buckets is known not to be NULL at this point; the test for this was
4118 * performed with the obj->valid_hash_sysv assignment.
4121 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4123 unsigned long symnum;
4124 Sym_Match_Result matchres;
4126 matchres.sym_out = NULL;
4127 matchres.vsymp = NULL;
4128 matchres.vcount = 0;
4130 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4131 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4132 if (symnum >= obj->nchains)
4133 return (ESRCH); /* Bad object */
4135 if (matched_symbol(req, obj, &matchres, symnum)) {
4136 req->sym_out = matchres.sym_out;
4137 req->defobj_out = obj;
4141 if (matchres.vcount == 1) {
4142 req->sym_out = matchres.vsymp;
4143 req->defobj_out = obj;
4149 /* Search for symbol using GNU hash function */
4151 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4153 Elf_Addr bloom_word;
4154 const Elf32_Word *hashval;
4156 Sym_Match_Result matchres;
4157 unsigned int h1, h2;
4158 unsigned long symnum;
4160 matchres.sym_out = NULL;
4161 matchres.vsymp = NULL;
4162 matchres.vcount = 0;
4164 /* Pick right bitmask word from Bloom filter array */
4165 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4166 obj->maskwords_bm_gnu];
4168 /* Calculate modulus word size of gnu hash and its derivative */
4169 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4170 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4172 /* Filter out the "definitely not in set" queries */
4173 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4176 /* Locate hash chain and corresponding value element*/
4177 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4180 hashval = &obj->chain_zero_gnu[bucket];
4182 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4183 symnum = hashval - obj->chain_zero_gnu;
4184 if (matched_symbol(req, obj, &matchres, symnum)) {
4185 req->sym_out = matchres.sym_out;
4186 req->defobj_out = obj;
4190 } while ((*hashval++ & 1) == 0);
4191 if (matchres.vcount == 1) {
4192 req->sym_out = matchres.vsymp;
4193 req->defobj_out = obj;
4200 trace_loaded_objects(Obj_Entry *obj)
4202 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4205 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4208 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4209 fmt1 = "\t%o => %p (%x)\n";
4211 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4212 fmt2 = "\t%o (%x)\n";
4214 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4216 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
4217 Needed_Entry *needed;
4223 if (list_containers && obj->needed != NULL)
4224 rtld_printf("%s:\n", obj->path);
4225 for (needed = obj->needed; needed; needed = needed->next) {
4226 if (needed->obj != NULL) {
4227 if (needed->obj->traced && !list_containers)
4229 needed->obj->traced = true;
4230 path = needed->obj->path;
4234 name = (char *)obj->strtab + needed->name;
4235 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4237 fmt = is_lib ? fmt1 : fmt2;
4238 while ((c = *fmt++) != '\0') {
4264 rtld_putstr(main_local);
4267 rtld_putstr(obj_main->path);
4274 rtld_printf("%d", sodp->sod_major);
4277 rtld_printf("%d", sodp->sod_minor);
4284 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4297 * Unload a dlopened object and its dependencies from memory and from
4298 * our data structures. It is assumed that the DAG rooted in the
4299 * object has already been unreferenced, and that the object has a
4300 * reference count of 0.
4303 unload_object(Obj_Entry *root)
4305 Obj_Entry *obj, *obj1;
4307 assert(root->refcount == 0);
4310 * Pass over the DAG removing unreferenced objects from
4311 * appropriate lists.
4313 unlink_object(root);
4315 /* Unmap all objects that are no longer referenced. */
4316 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) {
4317 if (obj->marker || obj->refcount != 0)
4319 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4320 obj->mapsize, 0, obj->path);
4321 dbg("unloading \"%s\"", obj->path);
4322 unload_filtees(root);
4323 munmap(obj->mapbase, obj->mapsize);
4324 linkmap_delete(obj);
4325 TAILQ_REMOVE(&obj_list, obj, next);
4332 unlink_object(Obj_Entry *root)
4336 if (root->refcount == 0) {
4337 /* Remove the object from the RTLD_GLOBAL list. */
4338 objlist_remove(&list_global, root);
4340 /* Remove the object from all objects' DAG lists. */
4341 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4342 objlist_remove(&elm->obj->dldags, root);
4343 if (elm->obj != root)
4344 unlink_object(elm->obj);
4350 ref_dag(Obj_Entry *root)
4354 assert(root->dag_inited);
4355 STAILQ_FOREACH(elm, &root->dagmembers, link)
4356 elm->obj->refcount++;
4360 unref_dag(Obj_Entry *root)
4364 assert(root->dag_inited);
4365 STAILQ_FOREACH(elm, &root->dagmembers, link)
4366 elm->obj->refcount--;
4370 * Common code for MD __tls_get_addr().
4372 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4374 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4376 Elf_Addr *newdtv, *dtv;
4377 RtldLockState lockstate;
4381 /* Check dtv generation in case new modules have arrived */
4382 if (dtv[0] != tls_dtv_generation) {
4383 wlock_acquire(rtld_bind_lock, &lockstate);
4384 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4386 if (to_copy > tls_max_index)
4387 to_copy = tls_max_index;
4388 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4389 newdtv[0] = tls_dtv_generation;
4390 newdtv[1] = tls_max_index;
4392 lock_release(rtld_bind_lock, &lockstate);
4393 dtv = *dtvp = newdtv;
4396 /* Dynamically allocate module TLS if necessary */
4397 if (dtv[index + 1] == 0) {
4398 /* Signal safe, wlock will block out signals. */
4399 wlock_acquire(rtld_bind_lock, &lockstate);
4400 if (!dtv[index + 1])
4401 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4402 lock_release(rtld_bind_lock, &lockstate);
4404 return ((void *)(dtv[index + 1] + offset));
4408 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4413 /* Check dtv generation in case new modules have arrived */
4414 if (__predict_true(dtv[0] == tls_dtv_generation &&
4415 dtv[index + 1] != 0))
4416 return ((void *)(dtv[index + 1] + offset));
4417 return (tls_get_addr_slow(dtvp, index, offset));
4420 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__)
4423 * Allocate Static TLS using the Variant I method.
4426 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4435 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4438 assert(tcbsize >= TLS_TCB_SIZE);
4439 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4440 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4442 if (oldtcb != NULL) {
4443 memcpy(tls, oldtcb, tls_static_space);
4446 /* Adjust the DTV. */
4448 for (i = 0; i < dtv[1]; i++) {
4449 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4450 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4451 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4455 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4457 dtv[0] = tls_dtv_generation;
4458 dtv[1] = tls_max_index;
4460 for (obj = globallist_curr(objs); obj != NULL;
4461 obj = globallist_next(obj)) {
4462 if (obj->tlsoffset > 0) {
4463 addr = (Elf_Addr)tls + obj->tlsoffset;
4464 if (obj->tlsinitsize > 0)
4465 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4466 if (obj->tlssize > obj->tlsinitsize)
4467 memset((void*) (addr + obj->tlsinitsize), 0,
4468 obj->tlssize - obj->tlsinitsize);
4469 dtv[obj->tlsindex + 1] = addr;
4478 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4481 Elf_Addr tlsstart, tlsend;
4484 assert(tcbsize >= TLS_TCB_SIZE);
4486 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4487 tlsend = tlsstart + tls_static_space;
4489 dtv = *(Elf_Addr **)tlsstart;
4491 for (i = 0; i < dtvsize; i++) {
4492 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4493 free((void*)dtv[i+2]);
4502 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4505 * Allocate Static TLS using the Variant II method.
4508 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4511 size_t size, ralign;
4513 Elf_Addr *dtv, *olddtv;
4514 Elf_Addr segbase, oldsegbase, addr;
4518 if (tls_static_max_align > ralign)
4519 ralign = tls_static_max_align;
4520 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4522 assert(tcbsize >= 2*sizeof(Elf_Addr));
4523 tls = malloc_aligned(size, ralign);
4524 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4526 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4527 ((Elf_Addr*)segbase)[0] = segbase;
4528 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4530 dtv[0] = tls_dtv_generation;
4531 dtv[1] = tls_max_index;
4535 * Copy the static TLS block over whole.
4537 oldsegbase = (Elf_Addr) oldtls;
4538 memcpy((void *)(segbase - tls_static_space),
4539 (const void *)(oldsegbase - tls_static_space),
4543 * If any dynamic TLS blocks have been created tls_get_addr(),
4546 olddtv = ((Elf_Addr**)oldsegbase)[1];
4547 for (i = 0; i < olddtv[1]; i++) {
4548 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4549 dtv[i+2] = olddtv[i+2];
4555 * We assume that this block was the one we created with
4556 * allocate_initial_tls().
4558 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4561 TAILQ_FOREACH_FROM(obj, &obj_list, next) {
4562 if (obj->marker || obj->tlsoffset == 0)
4564 addr = segbase - obj->tlsoffset;
4565 memset((void*) (addr + obj->tlsinitsize),
4566 0, obj->tlssize - obj->tlsinitsize);
4568 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4569 dtv[obj->tlsindex + 1] = addr;
4573 return (void*) segbase;
4577 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4580 size_t size, ralign;
4582 Elf_Addr tlsstart, tlsend;
4585 * Figure out the size of the initial TLS block so that we can
4586 * find stuff which ___tls_get_addr() allocated dynamically.
4589 if (tls_static_max_align > ralign)
4590 ralign = tls_static_max_align;
4591 size = round(tls_static_space, ralign);
4593 dtv = ((Elf_Addr**)tls)[1];
4595 tlsend = (Elf_Addr) tls;
4596 tlsstart = tlsend - size;
4597 for (i = 0; i < dtvsize; i++) {
4598 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4599 free_aligned((void *)dtv[i + 2]);
4603 free_aligned((void *)tlsstart);
4610 * Allocate TLS block for module with given index.
4613 allocate_module_tls(int index)
4618 TAILQ_FOREACH(obj, &obj_list, next) {
4621 if (obj->tlsindex == index)
4625 _rtld_error("Can't find module with TLS index %d", index);
4629 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4630 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4631 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4637 allocate_tls_offset(Obj_Entry *obj)
4644 if (obj->tlssize == 0) {
4645 obj->tls_done = true;
4649 if (tls_last_offset == 0)
4650 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4652 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4653 obj->tlssize, obj->tlsalign);
4656 * If we have already fixed the size of the static TLS block, we
4657 * must stay within that size. When allocating the static TLS, we
4658 * leave a small amount of space spare to be used for dynamically
4659 * loading modules which use static TLS.
4661 if (tls_static_space != 0) {
4662 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4664 } else if (obj->tlsalign > tls_static_max_align) {
4665 tls_static_max_align = obj->tlsalign;
4668 tls_last_offset = obj->tlsoffset = off;
4669 tls_last_size = obj->tlssize;
4670 obj->tls_done = true;
4676 free_tls_offset(Obj_Entry *obj)
4680 * If we were the last thing to allocate out of the static TLS
4681 * block, we give our space back to the 'allocator'. This is a
4682 * simplistic workaround to allow libGL.so.1 to be loaded and
4683 * unloaded multiple times.
4685 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4686 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4687 tls_last_offset -= obj->tlssize;
4693 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4696 RtldLockState lockstate;
4698 wlock_acquire(rtld_bind_lock, &lockstate);
4699 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
4701 lock_release(rtld_bind_lock, &lockstate);
4706 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4708 RtldLockState lockstate;
4710 wlock_acquire(rtld_bind_lock, &lockstate);
4711 free_tls(tcb, tcbsize, tcbalign);
4712 lock_release(rtld_bind_lock, &lockstate);
4716 object_add_name(Obj_Entry *obj, const char *name)
4722 entry = malloc(sizeof(Name_Entry) + len);
4724 if (entry != NULL) {
4725 strcpy(entry->name, name);
4726 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4731 object_match_name(const Obj_Entry *obj, const char *name)
4735 STAILQ_FOREACH(entry, &obj->names, link) {
4736 if (strcmp(name, entry->name) == 0)
4743 locate_dependency(const Obj_Entry *obj, const char *name)
4745 const Objlist_Entry *entry;
4746 const Needed_Entry *needed;
4748 STAILQ_FOREACH(entry, &list_main, link) {
4749 if (object_match_name(entry->obj, name))
4753 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4754 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4755 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4757 * If there is DT_NEEDED for the name we are looking for,
4758 * we are all set. Note that object might not be found if
4759 * dependency was not loaded yet, so the function can
4760 * return NULL here. This is expected and handled
4761 * properly by the caller.
4763 return (needed->obj);
4766 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4772 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4773 const Elf_Vernaux *vna)
4775 const Elf_Verdef *vd;
4776 const char *vername;
4778 vername = refobj->strtab + vna->vna_name;
4779 vd = depobj->verdef;
4781 _rtld_error("%s: version %s required by %s not defined",
4782 depobj->path, vername, refobj->path);
4786 if (vd->vd_version != VER_DEF_CURRENT) {
4787 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4788 depobj->path, vd->vd_version);
4791 if (vna->vna_hash == vd->vd_hash) {
4792 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4793 ((char *)vd + vd->vd_aux);
4794 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4797 if (vd->vd_next == 0)
4799 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4801 if (vna->vna_flags & VER_FLG_WEAK)
4803 _rtld_error("%s: version %s required by %s not found",
4804 depobj->path, vername, refobj->path);
4809 rtld_verify_object_versions(Obj_Entry *obj)
4811 const Elf_Verneed *vn;
4812 const Elf_Verdef *vd;
4813 const Elf_Verdaux *vda;
4814 const Elf_Vernaux *vna;
4815 const Obj_Entry *depobj;
4816 int maxvernum, vernum;
4818 if (obj->ver_checked)
4820 obj->ver_checked = true;
4824 * Walk over defined and required version records and figure out
4825 * max index used by any of them. Do very basic sanity checking
4829 while (vn != NULL) {
4830 if (vn->vn_version != VER_NEED_CURRENT) {
4831 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4832 obj->path, vn->vn_version);
4835 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4837 vernum = VER_NEED_IDX(vna->vna_other);
4838 if (vernum > maxvernum)
4840 if (vna->vna_next == 0)
4842 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4844 if (vn->vn_next == 0)
4846 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4850 while (vd != NULL) {
4851 if (vd->vd_version != VER_DEF_CURRENT) {
4852 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4853 obj->path, vd->vd_version);
4856 vernum = VER_DEF_IDX(vd->vd_ndx);
4857 if (vernum > maxvernum)
4859 if (vd->vd_next == 0)
4861 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4868 * Store version information in array indexable by version index.
4869 * Verify that object version requirements are satisfied along the
4872 obj->vernum = maxvernum + 1;
4873 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4876 while (vd != NULL) {
4877 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4878 vernum = VER_DEF_IDX(vd->vd_ndx);
4879 assert(vernum <= maxvernum);
4880 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4881 obj->vertab[vernum].hash = vd->vd_hash;
4882 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4883 obj->vertab[vernum].file = NULL;
4884 obj->vertab[vernum].flags = 0;
4886 if (vd->vd_next == 0)
4888 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4892 while (vn != NULL) {
4893 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4896 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4898 if (check_object_provided_version(obj, depobj, vna))
4900 vernum = VER_NEED_IDX(vna->vna_other);
4901 assert(vernum <= maxvernum);
4902 obj->vertab[vernum].hash = vna->vna_hash;
4903 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4904 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4905 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4906 VER_INFO_HIDDEN : 0;
4907 if (vna->vna_next == 0)
4909 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4911 if (vn->vn_next == 0)
4913 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4919 rtld_verify_versions(const Objlist *objlist)
4921 Objlist_Entry *entry;
4925 STAILQ_FOREACH(entry, objlist, link) {
4927 * Skip dummy objects or objects that have their version requirements
4930 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4932 if (rtld_verify_object_versions(entry->obj) == -1) {
4934 if (ld_tracing == NULL)
4938 if (rc == 0 || ld_tracing != NULL)
4939 rc = rtld_verify_object_versions(&obj_rtld);
4944 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4949 vernum = VER_NDX(obj->versyms[symnum]);
4950 if (vernum >= obj->vernum) {
4951 _rtld_error("%s: symbol %s has wrong verneed value %d",
4952 obj->path, obj->strtab + symnum, vernum);
4953 } else if (obj->vertab[vernum].hash != 0) {
4954 return &obj->vertab[vernum];
4961 _rtld_get_stack_prot(void)
4964 return (stack_prot);
4968 _rtld_is_dlopened(void *arg)
4971 RtldLockState lockstate;
4974 rlock_acquire(rtld_bind_lock, &lockstate);
4977 obj = obj_from_addr(arg);
4979 _rtld_error("No shared object contains address");
4980 lock_release(rtld_bind_lock, &lockstate);
4983 res = obj->dlopened ? 1 : 0;
4984 lock_release(rtld_bind_lock, &lockstate);
4989 map_stacks_exec(RtldLockState *lockstate)
4991 void (*thr_map_stacks_exec)(void);
4993 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4995 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4996 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4997 if (thr_map_stacks_exec != NULL) {
4998 stack_prot |= PROT_EXEC;
4999 thr_map_stacks_exec();
5004 symlook_init(SymLook *dst, const char *name)
5007 bzero(dst, sizeof(*dst));
5009 dst->hash = elf_hash(name);
5010 dst->hash_gnu = gnu_hash(name);
5014 symlook_init_from_req(SymLook *dst, const SymLook *src)
5017 dst->name = src->name;
5018 dst->hash = src->hash;
5019 dst->hash_gnu = src->hash_gnu;
5020 dst->ventry = src->ventry;
5021 dst->flags = src->flags;
5022 dst->defobj_out = NULL;
5023 dst->sym_out = NULL;
5024 dst->lockstate = src->lockstate;
5028 * Overrides for libc_pic-provided functions.
5032 __getosreldate(void)
5042 oid[1] = KERN_OSRELDATE;
5044 len = sizeof(osrel);
5045 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5046 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5058 void (*__cleanup)(void);
5059 int __isthreaded = 0;
5060 int _thread_autoinit_dummy_decl = 1;
5063 * No unresolved symbols for rtld.
5066 __pthread_cxa_finalize(struct dl_phdr_info *a)
5071 __stack_chk_fail(void)
5074 _rtld_error("stack overflow detected; terminated");
5077 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5083 _rtld_error("buffer overflow detected; terminated");
5088 rtld_strerror(int errnum)
5091 if (errnum < 0 || errnum >= sys_nerr)
5092 return ("Unknown error");
5093 return (sys_errlist[errnum]);