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>.
38 #error "GCC is needed to compile this file"
41 #include <sys/param.h>
42 #include <sys/mount.h>
45 #include <sys/sysctl.h>
47 #include <sys/utsname.h>
48 #include <sys/ktrace.h>
64 #include "rtld_printf.h"
68 #define PATH_RTLD "/libexec/ld-elf.so.1"
70 #define PATH_RTLD "/libexec/ld-elf32.so.1"
74 typedef void (*func_ptr_type)();
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 * Function declarations.
80 static const char *basename(const char *);
81 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
82 const Elf_Dyn **, const Elf_Dyn **);
83 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
85 static void digest_dynamic(Obj_Entry *, int);
86 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
87 static Obj_Entry *dlcheck(void *);
88 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
89 int lo_flags, int mode, RtldLockState *lockstate);
90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
92 static bool donelist_check(DoneList *, const Obj_Entry *);
93 static void errmsg_restore(char *);
94 static char *errmsg_save(void);
95 static void *fill_search_info(const char *, size_t, void *);
96 static char *find_library(const char *, const Obj_Entry *);
97 static const char *gethints(bool);
98 static void init_dag(Obj_Entry *);
99 static void init_pagesizes(Elf_Auxinfo **aux_info);
100 static void init_rtld(caddr_t, Elf_Auxinfo **);
101 static void initlist_add_neededs(Needed_Entry *, Objlist *);
102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
103 static void linkmap_add(Obj_Entry *);
104 static void linkmap_delete(Obj_Entry *);
105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
106 static void unload_filtees(Obj_Entry *);
107 static int load_needed_objects(Obj_Entry *, int);
108 static int load_preload_objects(void);
109 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
110 static void map_stacks_exec(RtldLockState *);
111 static Obj_Entry *obj_from_addr(const void *);
112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
113 static void objlist_call_init(Objlist *, RtldLockState *);
114 static void objlist_clear(Objlist *);
115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
116 static void objlist_init(Objlist *);
117 static void objlist_push_head(Objlist *, Obj_Entry *);
118 static void objlist_push_tail(Objlist *, Obj_Entry *);
119 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
120 static void objlist_remove(Objlist *, Obj_Entry *);
121 static void *path_enumerate(const char *, path_enum_proc, void *);
122 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
123 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
124 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
125 int flags, RtldLockState *lockstate);
126 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
128 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
129 int flags, RtldLockState *lockstate);
130 static int rtld_dirname(const char *, char *);
131 static int rtld_dirname_abs(const char *, char *);
132 static void *rtld_dlopen(const char *name, int fd, int mode);
133 static void rtld_exit(void);
134 static char *search_library_path(const char *, const char *);
135 static const void **get_program_var_addr(const char *, RtldLockState *);
136 static void set_program_var(const char *, const void *);
137 static int symlook_default(SymLook *, const Obj_Entry *refobj);
138 static int symlook_global(SymLook *, DoneList *);
139 static void symlook_init_from_req(SymLook *, const SymLook *);
140 static int symlook_list(SymLook *, const Objlist *, DoneList *);
141 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
142 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
143 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
144 static void trace_loaded_objects(Obj_Entry *);
145 static void unlink_object(Obj_Entry *);
146 static void unload_object(Obj_Entry *);
147 static void unref_dag(Obj_Entry *);
148 static void ref_dag(Obj_Entry *);
149 static char *origin_subst_one(Obj_Entry *, char *, const char *,
151 static char *origin_subst(Obj_Entry *, char *);
152 static bool obj_resolve_origin(Obj_Entry *obj);
153 static void preinit_main(void);
154 static int rtld_verify_versions(const Objlist *);
155 static int rtld_verify_object_versions(Obj_Entry *);
156 static void object_add_name(Obj_Entry *, const char *);
157 static int object_match_name(const Obj_Entry *, const char *);
158 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
159 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
160 struct dl_phdr_info *phdr_info);
161 static uint32_t gnu_hash(const char *);
162 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
163 const unsigned long);
165 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
166 void _r_debug_postinit(struct link_map *) __noinline __exported;
171 static char *error_message; /* Message for dlerror(), or NULL */
172 struct r_debug r_debug __exported; /* for GDB; */
173 static bool libmap_disable; /* Disable libmap */
174 static bool ld_loadfltr; /* Immediate filters processing */
175 static char *libmap_override; /* Maps to use in addition to libmap.conf */
176 static bool trust; /* False for setuid and setgid programs */
177 static bool dangerous_ld_env; /* True if environment variables have been
178 used to affect the libraries loaded */
179 static char *ld_bind_now; /* Environment variable for immediate binding */
180 static char *ld_debug; /* Environment variable for debugging */
181 static char *ld_library_path; /* Environment variable for search path */
182 static char *ld_preload; /* Environment variable for libraries to
184 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
185 static char *ld_tracing; /* Called from ldd to print libs */
186 static char *ld_utrace; /* Use utrace() to log events. */
187 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
188 static Obj_Entry **obj_tail; /* Link field of last object in list */
189 static Obj_Entry *obj_main; /* The main program shared object */
190 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
191 static unsigned int obj_count; /* Number of objects in obj_list */
192 static unsigned int obj_loads; /* Number of objects in obj_list */
194 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
195 STAILQ_HEAD_INITIALIZER(list_global);
196 static Objlist list_main = /* Objects loaded at program startup */
197 STAILQ_HEAD_INITIALIZER(list_main);
198 static Objlist list_fini = /* Objects needing fini() calls */
199 STAILQ_HEAD_INITIALIZER(list_fini);
201 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
203 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
205 extern Elf_Dyn _DYNAMIC;
206 #pragma weak _DYNAMIC
207 #ifndef RTLD_IS_DYNAMIC
208 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
211 int dlclose(void *) __exported;
212 char *dlerror(void) __exported;
213 void *dlopen(const char *, int) __exported;
214 void *fdlopen(int, int) __exported;
215 void *dlsym(void *, const char *) __exported;
216 dlfunc_t dlfunc(void *, const char *) __exported;
217 void *dlvsym(void *, const char *, const char *) __exported;
218 int dladdr(const void *, Dl_info *) __exported;
219 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
220 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
221 int dlinfo(void *, int , void *) __exported;
222 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
223 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
224 int _rtld_get_stack_prot(void) __exported;
225 int _rtld_is_dlopened(void *) __exported;
226 void _rtld_error(const char *, ...) __exported;
228 int npagesizes, osreldate;
231 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
233 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
234 static int max_stack_flags;
237 * Global declarations normally provided by crt1. The dynamic linker is
238 * not built with crt1, so we have to provide them ourselves.
244 * Used to pass argc, argv to init functions.
250 * Globals to control TLS allocation.
252 size_t tls_last_offset; /* Static TLS offset of last module */
253 size_t tls_last_size; /* Static TLS size of last module */
254 size_t tls_static_space; /* Static TLS space allocated */
255 size_t tls_static_max_align;
256 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
257 int tls_max_index = 1; /* Largest module index allocated */
259 bool ld_library_path_rpath = false;
262 * Fill in a DoneList with an allocation large enough to hold all of
263 * the currently-loaded objects. Keep this as a macro since it calls
264 * alloca and we want that to occur within the scope of the caller.
266 #define donelist_init(dlp) \
267 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
268 assert((dlp)->objs != NULL), \
269 (dlp)->num_alloc = obj_count, \
272 #define UTRACE_DLOPEN_START 1
273 #define UTRACE_DLOPEN_STOP 2
274 #define UTRACE_DLCLOSE_START 3
275 #define UTRACE_DLCLOSE_STOP 4
276 #define UTRACE_LOAD_OBJECT 5
277 #define UTRACE_UNLOAD_OBJECT 6
278 #define UTRACE_ADD_RUNDEP 7
279 #define UTRACE_PRELOAD_FINISHED 8
280 #define UTRACE_INIT_CALL 9
281 #define UTRACE_FINI_CALL 10
282 #define UTRACE_DLSYM_START 11
283 #define UTRACE_DLSYM_STOP 12
286 char sig[4]; /* 'RTLD' */
289 void *mapbase; /* Used for 'parent' and 'init/fini' */
291 int refcnt; /* Used for 'mode' */
292 char name[MAXPATHLEN];
295 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
296 if (ld_utrace != NULL) \
297 ld_utrace_log(e, h, mb, ms, r, n); \
301 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
302 int refcnt, const char *name)
304 struct utrace_rtld ut;
312 ut.mapbase = mapbase;
313 ut.mapsize = mapsize;
315 bzero(ut.name, sizeof(ut.name));
317 strlcpy(ut.name, name, sizeof(ut.name));
318 utrace(&ut, sizeof(ut));
322 * Main entry point for dynamic linking. The first argument is the
323 * stack pointer. The stack is expected to be laid out as described
324 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
325 * Specifically, the stack pointer points to a word containing
326 * ARGC. Following that in the stack is a null-terminated sequence
327 * of pointers to argument strings. Then comes a null-terminated
328 * sequence of pointers to environment strings. Finally, there is a
329 * sequence of "auxiliary vector" entries.
331 * The second argument points to a place to store the dynamic linker's
332 * exit procedure pointer and the third to a place to store the main
335 * The return value is the main program's entry point.
338 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
340 Elf_Auxinfo *aux_info[AT_COUNT];
348 Objlist_Entry *entry;
350 Obj_Entry **preload_tail;
351 Obj_Entry *last_interposer;
353 RtldLockState lockstate;
354 char *library_path_rpath;
359 * On entry, the dynamic linker itself has not been relocated yet.
360 * Be very careful not to reference any global data until after
361 * init_rtld has returned. It is OK to reference file-scope statics
362 * and string constants, and to call static and global functions.
365 /* Find the auxiliary vector on the stack. */
368 sp += argc + 1; /* Skip over arguments and NULL terminator */
370 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
372 aux = (Elf_Auxinfo *) sp;
374 /* Digest the auxiliary vector. */
375 for (i = 0; i < AT_COUNT; i++)
377 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
378 if (auxp->a_type < AT_COUNT)
379 aux_info[auxp->a_type] = auxp;
382 /* Initialize and relocate ourselves. */
383 assert(aux_info[AT_BASE] != NULL);
384 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
386 __progname = obj_rtld.path;
387 argv0 = argv[0] != NULL ? argv[0] : "(null)";
392 if (aux_info[AT_CANARY] != NULL &&
393 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
394 i = aux_info[AT_CANARYLEN]->a_un.a_val;
395 if (i > sizeof(__stack_chk_guard))
396 i = sizeof(__stack_chk_guard);
397 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
402 len = sizeof(__stack_chk_guard);
403 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
404 len != sizeof(__stack_chk_guard)) {
405 /* If sysctl was unsuccessful, use the "terminator canary". */
406 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
407 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
408 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
409 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
413 trust = !issetugid();
415 ld_bind_now = getenv(LD_ "BIND_NOW");
417 * If the process is tainted, then we un-set the dangerous environment
418 * variables. The process will be marked as tainted until setuid(2)
419 * is called. If any child process calls setuid(2) we do not want any
420 * future processes to honor the potentially un-safe variables.
423 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
424 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
425 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
426 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
427 _rtld_error("environment corrupt; aborting");
431 ld_debug = getenv(LD_ "DEBUG");
432 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
433 libmap_override = getenv(LD_ "LIBMAP");
434 ld_library_path = getenv(LD_ "LIBRARY_PATH");
435 ld_preload = getenv(LD_ "PRELOAD");
436 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
437 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
438 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
439 if (library_path_rpath != NULL) {
440 if (library_path_rpath[0] == 'y' ||
441 library_path_rpath[0] == 'Y' ||
442 library_path_rpath[0] == '1')
443 ld_library_path_rpath = true;
445 ld_library_path_rpath = false;
447 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
448 (ld_library_path != NULL) || (ld_preload != NULL) ||
449 (ld_elf_hints_path != NULL) || ld_loadfltr;
450 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
451 ld_utrace = getenv(LD_ "UTRACE");
453 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
454 ld_elf_hints_path = _PATH_ELF_HINTS;
456 if (ld_debug != NULL && *ld_debug != '\0')
458 dbg("%s is initialized, base address = %p", __progname,
459 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
460 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
461 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
463 dbg("initializing thread locks");
467 * Load the main program, or process its program header if it is
470 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
471 int fd = aux_info[AT_EXECFD]->a_un.a_val;
472 dbg("loading main program");
473 obj_main = map_object(fd, argv0, NULL);
475 if (obj_main == NULL)
477 max_stack_flags = obj->stack_flags;
478 } else { /* Main program already loaded. */
479 const Elf_Phdr *phdr;
483 dbg("processing main program's program header");
484 assert(aux_info[AT_PHDR] != NULL);
485 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
486 assert(aux_info[AT_PHNUM] != NULL);
487 phnum = aux_info[AT_PHNUM]->a_un.a_val;
488 assert(aux_info[AT_PHENT] != NULL);
489 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
490 assert(aux_info[AT_ENTRY] != NULL);
491 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
492 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
496 if (aux_info[AT_EXECPATH] != 0) {
498 char buf[MAXPATHLEN];
500 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
501 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
502 if (kexecpath[0] == '/')
503 obj_main->path = kexecpath;
504 else if (getcwd(buf, sizeof(buf)) == NULL ||
505 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
506 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
507 obj_main->path = xstrdup(argv0);
509 obj_main->path = xstrdup(buf);
511 dbg("No AT_EXECPATH");
512 obj_main->path = xstrdup(argv0);
514 dbg("obj_main path %s", obj_main->path);
515 obj_main->mainprog = true;
517 if (aux_info[AT_STACKPROT] != NULL &&
518 aux_info[AT_STACKPROT]->a_un.a_val != 0)
519 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
523 * Get the actual dynamic linker pathname from the executable if
524 * possible. (It should always be possible.) That ensures that
525 * gdb will find the right dynamic linker even if a non-standard
528 if (obj_main->interp != NULL &&
529 strcmp(obj_main->interp, obj_rtld.path) != 0) {
531 obj_rtld.path = xstrdup(obj_main->interp);
532 __progname = obj_rtld.path;
536 digest_dynamic(obj_main, 0);
537 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
538 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
539 obj_main->dynsymcount);
541 linkmap_add(obj_main);
542 linkmap_add(&obj_rtld);
544 /* Link the main program into the list of objects. */
545 *obj_tail = obj_main;
546 obj_tail = &obj_main->next;
550 /* Initialize a fake symbol for resolving undefined weak references. */
551 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
552 sym_zero.st_shndx = SHN_UNDEF;
553 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
556 libmap_disable = (bool)lm_init(libmap_override);
558 dbg("loading LD_PRELOAD libraries");
559 if (load_preload_objects() == -1)
561 preload_tail = obj_tail;
563 dbg("loading needed objects");
564 if (load_needed_objects(obj_main, 0) == -1)
567 /* Make a list of all objects loaded at startup. */
568 last_interposer = obj_main;
569 for (obj = obj_list; obj != NULL; obj = obj->next) {
570 if (obj->z_interpose && obj != obj_main) {
571 objlist_put_after(&list_main, last_interposer, obj);
572 last_interposer = obj;
574 objlist_push_tail(&list_main, obj);
579 dbg("checking for required versions");
580 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
583 if (ld_tracing) { /* We're done */
584 trace_loaded_objects(obj_main);
588 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
589 dump_relocations(obj_main);
594 * Processing tls relocations requires having the tls offsets
595 * initialized. Prepare offsets before starting initial
596 * relocation processing.
598 dbg("initializing initial thread local storage offsets");
599 STAILQ_FOREACH(entry, &list_main, link) {
601 * Allocate all the initial objects out of the static TLS
602 * block even if they didn't ask for it.
604 allocate_tls_offset(entry->obj);
607 if (relocate_objects(obj_main,
608 ld_bind_now != NULL && *ld_bind_now != '\0',
609 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
612 dbg("doing copy relocations");
613 if (do_copy_relocations(obj_main) == -1)
616 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
617 dump_relocations(obj_main);
622 * Setup TLS for main thread. This must be done after the
623 * relocations are processed, since tls initialization section
624 * might be the subject for relocations.
626 dbg("initializing initial thread local storage");
627 allocate_initial_tls(obj_list);
629 dbg("initializing key program variables");
630 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
631 set_program_var("environ", env);
632 set_program_var("__elf_aux_vector", aux);
634 /* Make a list of init functions to call. */
635 objlist_init(&initlist);
636 initlist_add_objects(obj_list, preload_tail, &initlist);
638 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
640 map_stacks_exec(NULL);
642 dbg("resolving ifuncs");
643 if (resolve_objects_ifunc(obj_main,
644 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
648 if (!obj_main->crt_no_init) {
650 * Make sure we don't call the main program's init and fini
651 * functions for binaries linked with old crt1 which calls
654 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
655 obj_main->preinit_array = obj_main->init_array =
656 obj_main->fini_array = (Elf_Addr)NULL;
659 wlock_acquire(rtld_bind_lock, &lockstate);
660 if (obj_main->crt_no_init)
662 objlist_call_init(&initlist, &lockstate);
663 _r_debug_postinit(&obj_main->linkmap);
664 objlist_clear(&initlist);
665 dbg("loading filtees");
666 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
667 if (ld_loadfltr || obj->z_loadfltr)
668 load_filtees(obj, 0, &lockstate);
670 lock_release(rtld_bind_lock, &lockstate);
672 dbg("transferring control to program entry point = %p", obj_main->entry);
674 /* Return the exit procedure and the program entry point. */
675 *exit_proc = rtld_exit;
677 return (func_ptr_type) obj_main->entry;
681 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
686 ptr = (void *)make_function_pointer(def, obj);
687 target = ((Elf_Addr (*)(void))ptr)();
688 return ((void *)target);
692 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
696 const Obj_Entry *defobj;
699 RtldLockState lockstate;
701 rlock_acquire(rtld_bind_lock, &lockstate);
702 if (sigsetjmp(lockstate.env, 0) != 0)
703 lock_upgrade(rtld_bind_lock, &lockstate);
705 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
707 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
709 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
710 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
714 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
715 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
717 target = (Elf_Addr)(defobj->relocbase + def->st_value);
719 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
720 defobj->strtab + def->st_name, basename(obj->path),
721 (void *)target, basename(defobj->path));
724 * Write the new contents for the jmpslot. Note that depending on
725 * architecture, the value which we need to return back to the
726 * lazy binding trampoline may or may not be the target
727 * address. The value returned from reloc_jmpslot() is the value
728 * that the trampoline needs.
730 target = reloc_jmpslot(where, target, defobj, obj, rel);
731 lock_release(rtld_bind_lock, &lockstate);
736 * Error reporting function. Use it like printf. If formats the message
737 * into a buffer, and sets things up so that the next call to dlerror()
738 * will return the message.
741 _rtld_error(const char *fmt, ...)
743 static char buf[512];
747 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
753 * Return a dynamically-allocated copy of the current error message, if any.
758 return error_message == NULL ? NULL : xstrdup(error_message);
762 * Restore the current error message from a copy which was previously saved
763 * by errmsg_save(). The copy is freed.
766 errmsg_restore(char *saved_msg)
768 if (saved_msg == NULL)
769 error_message = NULL;
771 _rtld_error("%s", saved_msg);
777 basename(const char *name)
779 const char *p = strrchr(name, '/');
780 return p != NULL ? p + 1 : name;
783 static struct utsname uts;
786 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
787 const char *subst, bool may_free)
789 char *p, *p1, *res, *resp;
790 int subst_len, kw_len, subst_count, old_len, new_len;
795 * First, count the number of the keyword occurences, to
796 * preallocate the final string.
798 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
805 * If the keyword is not found, just return.
807 * Return non-substituted string if resolution failed. We
808 * cannot do anything more reasonable, the failure mode of the
809 * caller is unresolved library anyway.
811 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
812 return (may_free ? real : xstrdup(real));
814 subst = obj->origin_path;
817 * There is indeed something to substitute. Calculate the
818 * length of the resulting string, and allocate it.
820 subst_len = strlen(subst);
821 old_len = strlen(real);
822 new_len = old_len + (subst_len - kw_len) * subst_count;
823 res = xmalloc(new_len + 1);
826 * Now, execute the substitution loop.
828 for (p = real, resp = res, *resp = '\0';;) {
831 /* Copy the prefix before keyword. */
832 memcpy(resp, p, p1 - p);
834 /* Keyword replacement. */
835 memcpy(resp, subst, subst_len);
843 /* Copy to the end of string and finish. */
851 origin_subst(Obj_Entry *obj, char *real)
853 char *res1, *res2, *res3, *res4;
855 if (obj == NULL || !trust)
856 return (xstrdup(real));
857 if (uts.sysname[0] == '\0') {
858 if (uname(&uts) != 0) {
859 _rtld_error("utsname failed: %d", errno);
863 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
864 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
865 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
866 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
873 const char *msg = dlerror();
877 rtld_fdputstr(STDERR_FILENO, msg);
878 rtld_fdputchar(STDERR_FILENO, '\n');
883 * Process a shared object's DYNAMIC section, and save the important
884 * information in its Obj_Entry structure.
887 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
888 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
891 Needed_Entry **needed_tail = &obj->needed;
892 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
893 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
894 const Elf_Hashelt *hashtab;
895 const Elf32_Word *hashval;
896 Elf32_Word bkt, nmaskwords;
898 int plttype = DT_REL;
904 obj->bind_now = false;
905 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
906 switch (dynp->d_tag) {
909 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
913 obj->relsize = dynp->d_un.d_val;
917 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
921 obj->pltrel = (const Elf_Rel *)
922 (obj->relocbase + dynp->d_un.d_ptr);
926 obj->pltrelsize = dynp->d_un.d_val;
930 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
934 obj->relasize = dynp->d_un.d_val;
938 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
942 plttype = dynp->d_un.d_val;
943 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
947 obj->symtab = (const Elf_Sym *)
948 (obj->relocbase + dynp->d_un.d_ptr);
952 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
956 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
960 obj->strsize = dynp->d_un.d_val;
964 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
969 obj->verneednum = dynp->d_un.d_val;
973 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
978 obj->verdefnum = dynp->d_un.d_val;
982 obj->versyms = (const Elf_Versym *)(obj->relocbase +
988 hashtab = (const Elf_Hashelt *)(obj->relocbase +
990 obj->nbuckets = hashtab[0];
991 obj->nchains = hashtab[1];
992 obj->buckets = hashtab + 2;
993 obj->chains = obj->buckets + obj->nbuckets;
994 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
995 obj->buckets != NULL;
1001 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1003 obj->nbuckets_gnu = hashtab[0];
1004 obj->symndx_gnu = hashtab[1];
1005 nmaskwords = hashtab[2];
1006 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1007 obj->maskwords_bm_gnu = nmaskwords - 1;
1008 obj->shift2_gnu = hashtab[3];
1009 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1010 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1011 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1013 /* Number of bitmask words is required to be power of 2 */
1014 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1015 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1021 Needed_Entry *nep = NEW(Needed_Entry);
1022 nep->name = dynp->d_un.d_val;
1027 needed_tail = &nep->next;
1033 Needed_Entry *nep = NEW(Needed_Entry);
1034 nep->name = dynp->d_un.d_val;
1038 *needed_filtees_tail = nep;
1039 needed_filtees_tail = &nep->next;
1045 Needed_Entry *nep = NEW(Needed_Entry);
1046 nep->name = dynp->d_un.d_val;
1050 *needed_aux_filtees_tail = nep;
1051 needed_aux_filtees_tail = &nep->next;
1056 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1060 obj->textrel = true;
1064 obj->symbolic = true;
1069 * We have to wait until later to process this, because we
1070 * might not have gotten the address of the string table yet.
1080 *dyn_runpath = dynp;
1084 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1087 case DT_PREINIT_ARRAY:
1088 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1091 case DT_PREINIT_ARRAYSZ:
1092 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1096 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1099 case DT_INIT_ARRAYSZ:
1100 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1104 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1108 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1111 case DT_FINI_ARRAYSZ:
1112 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1116 * Don't process DT_DEBUG on MIPS as the dynamic section
1117 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1122 /* XXX - not implemented yet */
1124 dbg("Filling in DT_DEBUG entry");
1125 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1130 if (dynp->d_un.d_val & DF_ORIGIN)
1131 obj->z_origin = true;
1132 if (dynp->d_un.d_val & DF_SYMBOLIC)
1133 obj->symbolic = true;
1134 if (dynp->d_un.d_val & DF_TEXTREL)
1135 obj->textrel = true;
1136 if (dynp->d_un.d_val & DF_BIND_NOW)
1137 obj->bind_now = true;
1138 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1142 case DT_MIPS_LOCAL_GOTNO:
1143 obj->local_gotno = dynp->d_un.d_val;
1146 case DT_MIPS_SYMTABNO:
1147 obj->symtabno = dynp->d_un.d_val;
1150 case DT_MIPS_GOTSYM:
1151 obj->gotsym = dynp->d_un.d_val;
1154 case DT_MIPS_RLD_MAP:
1155 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1160 if (dynp->d_un.d_val & DF_1_NOOPEN)
1161 obj->z_noopen = true;
1162 if (dynp->d_un.d_val & DF_1_ORIGIN)
1163 obj->z_origin = true;
1164 if (dynp->d_un.d_val & DF_1_GLOBAL)
1165 obj->z_global = true;
1166 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1167 obj->bind_now = true;
1168 if (dynp->d_un.d_val & DF_1_NODELETE)
1169 obj->z_nodelete = true;
1170 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1171 obj->z_loadfltr = true;
1172 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1173 obj->z_interpose = true;
1174 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1175 obj->z_nodeflib = true;
1180 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1187 obj->traced = false;
1189 if (plttype == DT_RELA) {
1190 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1192 obj->pltrelasize = obj->pltrelsize;
1193 obj->pltrelsize = 0;
1196 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1197 if (obj->valid_hash_sysv)
1198 obj->dynsymcount = obj->nchains;
1199 else if (obj->valid_hash_gnu) {
1200 obj->dynsymcount = 0;
1201 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1202 if (obj->buckets_gnu[bkt] == 0)
1204 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1207 while ((*hashval++ & 1u) == 0);
1209 obj->dynsymcount += obj->symndx_gnu;
1214 obj_resolve_origin(Obj_Entry *obj)
1217 if (obj->origin_path != NULL)
1219 obj->origin_path = xmalloc(PATH_MAX);
1220 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1224 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1225 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1228 if (obj->z_origin && !obj_resolve_origin(obj))
1231 if (dyn_runpath != NULL) {
1232 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1233 obj->runpath = origin_subst(obj, obj->runpath);
1234 } else if (dyn_rpath != NULL) {
1235 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1236 obj->rpath = origin_subst(obj, obj->rpath);
1238 if (dyn_soname != NULL)
1239 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1243 digest_dynamic(Obj_Entry *obj, int early)
1245 const Elf_Dyn *dyn_rpath;
1246 const Elf_Dyn *dyn_soname;
1247 const Elf_Dyn *dyn_runpath;
1249 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1250 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1254 * Process a shared object's program header. This is used only for the
1255 * main program, when the kernel has already loaded the main program
1256 * into memory before calling the dynamic linker. It creates and
1257 * returns an Obj_Entry structure.
1260 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1263 const Elf_Phdr *phlimit = phdr + phnum;
1265 Elf_Addr note_start, note_end;
1269 for (ph = phdr; ph < phlimit; ph++) {
1270 if (ph->p_type != PT_PHDR)
1274 obj->phsize = ph->p_memsz;
1275 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1279 obj->stack_flags = PF_X | PF_R | PF_W;
1281 for (ph = phdr; ph < phlimit; ph++) {
1282 switch (ph->p_type) {
1285 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1289 if (nsegs == 0) { /* First load segment */
1290 obj->vaddrbase = trunc_page(ph->p_vaddr);
1291 obj->mapbase = obj->vaddrbase + obj->relocbase;
1292 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1294 } else { /* Last load segment */
1295 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1302 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1307 obj->tlssize = ph->p_memsz;
1308 obj->tlsalign = ph->p_align;
1309 obj->tlsinitsize = ph->p_filesz;
1310 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1314 obj->stack_flags = ph->p_flags;
1318 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1319 obj->relro_size = round_page(ph->p_memsz);
1323 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1324 note_end = note_start + ph->p_filesz;
1325 digest_notes(obj, note_start, note_end);
1330 _rtld_error("%s: too few PT_LOAD segments", path);
1339 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1341 const Elf_Note *note;
1342 const char *note_name;
1345 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1346 note = (const Elf_Note *)((const char *)(note + 1) +
1347 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1348 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1349 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1350 note->n_descsz != sizeof(int32_t))
1352 if (note->n_type != ABI_NOTETYPE &&
1353 note->n_type != CRT_NOINIT_NOTETYPE)
1355 note_name = (const char *)(note + 1);
1356 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1357 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1359 switch (note->n_type) {
1361 /* FreeBSD osrel note */
1362 p = (uintptr_t)(note + 1);
1363 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1364 obj->osrel = *(const int32_t *)(p);
1365 dbg("note osrel %d", obj->osrel);
1367 case CRT_NOINIT_NOTETYPE:
1368 /* FreeBSD 'crt does not call init' note */
1369 obj->crt_no_init = true;
1370 dbg("note crt_no_init");
1377 dlcheck(void *handle)
1381 for (obj = obj_list; obj != NULL; obj = obj->next)
1382 if (obj == (Obj_Entry *) handle)
1385 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1386 _rtld_error("Invalid shared object handle %p", handle);
1393 * If the given object is already in the donelist, return true. Otherwise
1394 * add the object to the list and return false.
1397 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1401 for (i = 0; i < dlp->num_used; i++)
1402 if (dlp->objs[i] == obj)
1405 * Our donelist allocation should always be sufficient. But if
1406 * our threads locking isn't working properly, more shared objects
1407 * could have been loaded since we allocated the list. That should
1408 * never happen, but we'll handle it properly just in case it does.
1410 if (dlp->num_used < dlp->num_alloc)
1411 dlp->objs[dlp->num_used++] = obj;
1416 * Hash function for symbol table lookup. Don't even think about changing
1417 * this. It is specified by the System V ABI.
1420 elf_hash(const char *name)
1422 const unsigned char *p = (const unsigned char *) name;
1423 unsigned long h = 0;
1426 while (*p != '\0') {
1427 h = (h << 4) + *p++;
1428 if ((g = h & 0xf0000000) != 0)
1436 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1437 * unsigned in case it's implemented with a wider type.
1440 gnu_hash(const char *s)
1446 for (c = *s; c != '\0'; c = *++s)
1448 return (h & 0xffffffff);
1452 * Find the library with the given name, and return its full pathname.
1453 * The returned string is dynamically allocated. Generates an error
1454 * message and returns NULL if the library cannot be found.
1456 * If the second argument is non-NULL, then it refers to an already-
1457 * loaded shared object, whose library search path will be searched.
1459 * The search order is:
1460 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1461 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1463 * DT_RUNPATH in the referencing file
1464 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1466 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1468 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1471 find_library(const char *xname, const Obj_Entry *refobj)
1475 bool nodeflib, objgiven;
1477 objgiven = refobj != NULL;
1478 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1479 if (xname[0] != '/' && !trust) {
1480 _rtld_error("Absolute pathname required for shared object \"%s\"",
1484 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1485 __DECONST(char *, xname)));
1488 if (libmap_disable || !objgiven ||
1489 (name = lm_find(refobj->path, xname)) == NULL)
1490 name = (char *)xname;
1492 dbg(" Searching for \"%s\"", name);
1495 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1496 * back to pre-conforming behaviour if user requested so with
1497 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1500 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1501 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1503 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1504 (pathname = search_library_path(name, gethints(false))) != NULL ||
1505 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1508 nodeflib = objgiven ? refobj->z_nodeflib : false;
1510 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1511 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1512 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1513 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1515 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1516 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1517 (objgiven && !nodeflib &&
1518 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1522 if (objgiven && refobj->path != NULL) {
1523 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1524 name, basename(refobj->path));
1526 _rtld_error("Shared object \"%s\" not found", name);
1532 * Given a symbol number in a referencing object, find the corresponding
1533 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1534 * no definition was found. Returns a pointer to the Obj_Entry of the
1535 * defining object via the reference parameter DEFOBJ_OUT.
1538 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1539 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1540 RtldLockState *lockstate)
1544 const Obj_Entry *defobj;
1550 * If we have already found this symbol, get the information from
1553 if (symnum >= refobj->dynsymcount)
1554 return NULL; /* Bad object */
1555 if (cache != NULL && cache[symnum].sym != NULL) {
1556 *defobj_out = cache[symnum].obj;
1557 return cache[symnum].sym;
1560 ref = refobj->symtab + symnum;
1561 name = refobj->strtab + ref->st_name;
1566 * We don't have to do a full scale lookup if the symbol is local.
1567 * We know it will bind to the instance in this load module; to
1568 * which we already have a pointer (ie ref). By not doing a lookup,
1569 * we not only improve performance, but it also avoids unresolvable
1570 * symbols when local symbols are not in the hash table. This has
1571 * been seen with the ia64 toolchain.
1573 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1574 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1575 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1578 symlook_init(&req, name);
1580 req.ventry = fetch_ventry(refobj, symnum);
1581 req.lockstate = lockstate;
1582 res = symlook_default(&req, refobj);
1585 defobj = req.defobj_out;
1593 * If we found no definition and the reference is weak, treat the
1594 * symbol as having the value zero.
1596 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1602 *defobj_out = defobj;
1603 /* Record the information in the cache to avoid subsequent lookups. */
1604 if (cache != NULL) {
1605 cache[symnum].sym = def;
1606 cache[symnum].obj = defobj;
1609 if (refobj != &obj_rtld)
1610 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1616 * Return the search path from the ldconfig hints file, reading it if
1617 * necessary. If nostdlib is true, then the default search paths are
1618 * not added to result.
1620 * Returns NULL if there are problems with the hints file,
1621 * or if the search path there is empty.
1624 gethints(bool nostdlib)
1626 static char *hints, *filtered_path;
1627 struct elfhints_hdr hdr;
1628 struct fill_search_info_args sargs, hargs;
1629 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1630 struct dl_serpath *SLPpath, *hintpath;
1632 unsigned int SLPndx, hintndx, fndx, fcount;
1637 /* First call, read the hints file */
1638 if (hints == NULL) {
1639 /* Keep from trying again in case the hints file is bad. */
1642 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1644 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1645 hdr.magic != ELFHINTS_MAGIC ||
1650 p = xmalloc(hdr.dirlistlen + 1);
1651 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1652 read(fd, p, hdr.dirlistlen + 1) !=
1653 (ssize_t)hdr.dirlistlen + 1) {
1663 * If caller agreed to receive list which includes the default
1664 * paths, we are done. Otherwise, if we still did not
1665 * calculated filtered result, do it now.
1668 return (hints[0] != '\0' ? hints : NULL);
1669 if (filtered_path != NULL)
1673 * Obtain the list of all configured search paths, and the
1674 * list of the default paths.
1676 * First estimate the size of the results.
1678 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1680 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1683 sargs.request = RTLD_DI_SERINFOSIZE;
1684 sargs.serinfo = &smeta;
1685 hargs.request = RTLD_DI_SERINFOSIZE;
1686 hargs.serinfo = &hmeta;
1688 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1689 path_enumerate(p, fill_search_info, &hargs);
1691 SLPinfo = xmalloc(smeta.dls_size);
1692 hintinfo = xmalloc(hmeta.dls_size);
1695 * Next fetch both sets of paths.
1697 sargs.request = RTLD_DI_SERINFO;
1698 sargs.serinfo = SLPinfo;
1699 sargs.serpath = &SLPinfo->dls_serpath[0];
1700 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1702 hargs.request = RTLD_DI_SERINFO;
1703 hargs.serinfo = hintinfo;
1704 hargs.serpath = &hintinfo->dls_serpath[0];
1705 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1707 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1708 path_enumerate(p, fill_search_info, &hargs);
1711 * Now calculate the difference between two sets, by excluding
1712 * standard paths from the full set.
1716 filtered_path = xmalloc(hdr.dirlistlen + 1);
1717 hintpath = &hintinfo->dls_serpath[0];
1718 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1720 SLPpath = &SLPinfo->dls_serpath[0];
1722 * Check each standard path against current.
1724 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1725 /* matched, skip the path */
1726 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1734 * Not matched against any standard path, add the path
1735 * to result. Separate consequtive paths with ':'.
1738 filtered_path[fndx] = ':';
1742 flen = strlen(hintpath->dls_name);
1743 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1746 filtered_path[fndx] = '\0';
1752 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1756 init_dag(Obj_Entry *root)
1758 const Needed_Entry *needed;
1759 const Objlist_Entry *elm;
1762 if (root->dag_inited)
1764 donelist_init(&donelist);
1766 /* Root object belongs to own DAG. */
1767 objlist_push_tail(&root->dldags, root);
1768 objlist_push_tail(&root->dagmembers, root);
1769 donelist_check(&donelist, root);
1772 * Add dependencies of root object to DAG in breadth order
1773 * by exploiting the fact that each new object get added
1774 * to the tail of the dagmembers list.
1776 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1777 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1778 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1780 objlist_push_tail(&needed->obj->dldags, root);
1781 objlist_push_tail(&root->dagmembers, needed->obj);
1784 root->dag_inited = true;
1788 process_z(Obj_Entry *root)
1790 const Objlist_Entry *elm;
1794 * Walk over object DAG and process every dependent object
1795 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
1796 * to grow their own DAG.
1798 * For DF_1_GLOBAL, DAG is required for symbol lookups in
1799 * symlook_global() to work.
1801 * For DF_1_NODELETE, the DAG should have its reference upped.
1803 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1807 if (obj->z_nodelete && !obj->ref_nodel) {
1808 dbg("obj %s -z nodelete", obj->path);
1811 obj->ref_nodel = true;
1813 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
1814 dbg("obj %s -z global", obj->path);
1815 objlist_push_tail(&list_global, obj);
1821 * Initialize the dynamic linker. The argument is the address at which
1822 * the dynamic linker has been mapped into memory. The primary task of
1823 * this function is to relocate the dynamic linker.
1826 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1828 Obj_Entry objtmp; /* Temporary rtld object */
1829 const Elf_Dyn *dyn_rpath;
1830 const Elf_Dyn *dyn_soname;
1831 const Elf_Dyn *dyn_runpath;
1833 #ifdef RTLD_INIT_PAGESIZES_EARLY
1834 /* The page size is required by the dynamic memory allocator. */
1835 init_pagesizes(aux_info);
1839 * Conjure up an Obj_Entry structure for the dynamic linker.
1841 * The "path" member can't be initialized yet because string constants
1842 * cannot yet be accessed. Below we will set it correctly.
1844 memset(&objtmp, 0, sizeof(objtmp));
1847 objtmp.mapbase = mapbase;
1849 objtmp.relocbase = mapbase;
1851 if (RTLD_IS_DYNAMIC()) {
1852 objtmp.dynamic = rtld_dynamic(&objtmp);
1853 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1854 assert(objtmp.needed == NULL);
1855 #if !defined(__mips__)
1856 /* MIPS has a bogus DT_TEXTREL. */
1857 assert(!objtmp.textrel);
1861 * Temporarily put the dynamic linker entry into the object list, so
1862 * that symbols can be found.
1865 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1868 /* Initialize the object list. */
1869 obj_tail = &obj_list;
1871 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1872 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1874 #ifndef RTLD_INIT_PAGESIZES_EARLY
1875 /* The page size is required by the dynamic memory allocator. */
1876 init_pagesizes(aux_info);
1879 if (aux_info[AT_OSRELDATE] != NULL)
1880 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1882 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1884 /* Replace the path with a dynamically allocated copy. */
1885 obj_rtld.path = xstrdup(PATH_RTLD);
1887 r_debug.r_brk = r_debug_state;
1888 r_debug.r_state = RT_CONSISTENT;
1892 * Retrieve the array of supported page sizes. The kernel provides the page
1893 * sizes in increasing order.
1896 init_pagesizes(Elf_Auxinfo **aux_info)
1898 static size_t psa[MAXPAGESIZES];
1902 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1904 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1905 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1908 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1911 /* As a fallback, retrieve the base page size. */
1912 size = sizeof(psa[0]);
1913 if (aux_info[AT_PAGESZ] != NULL) {
1914 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1918 mib[1] = HW_PAGESIZE;
1922 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1923 _rtld_error("sysctl for hw.pagesize(s) failed");
1929 npagesizes = size / sizeof(pagesizes[0]);
1930 /* Discard any invalid entries at the end of the array. */
1931 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1936 * Add the init functions from a needed object list (and its recursive
1937 * needed objects) to "list". This is not used directly; it is a helper
1938 * function for initlist_add_objects(). The write lock must be held
1939 * when this function is called.
1942 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1944 /* Recursively process the successor needed objects. */
1945 if (needed->next != NULL)
1946 initlist_add_neededs(needed->next, list);
1948 /* Process the current needed object. */
1949 if (needed->obj != NULL)
1950 initlist_add_objects(needed->obj, &needed->obj->next, list);
1954 * Scan all of the DAGs rooted in the range of objects from "obj" to
1955 * "tail" and add their init functions to "list". This recurses over
1956 * the DAGs and ensure the proper init ordering such that each object's
1957 * needed libraries are initialized before the object itself. At the
1958 * same time, this function adds the objects to the global finalization
1959 * list "list_fini" in the opposite order. The write lock must be
1960 * held when this function is called.
1963 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1966 if (obj->init_scanned || obj->init_done)
1968 obj->init_scanned = true;
1970 /* Recursively process the successor objects. */
1971 if (&obj->next != tail)
1972 initlist_add_objects(obj->next, tail, list);
1974 /* Recursively process the needed objects. */
1975 if (obj->needed != NULL)
1976 initlist_add_neededs(obj->needed, list);
1977 if (obj->needed_filtees != NULL)
1978 initlist_add_neededs(obj->needed_filtees, list);
1979 if (obj->needed_aux_filtees != NULL)
1980 initlist_add_neededs(obj->needed_aux_filtees, list);
1982 /* Add the object to the init list. */
1983 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1984 obj->init_array != (Elf_Addr)NULL)
1985 objlist_push_tail(list, obj);
1987 /* Add the object to the global fini list in the reverse order. */
1988 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1989 && !obj->on_fini_list) {
1990 objlist_push_head(&list_fini, obj);
1991 obj->on_fini_list = true;
1996 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2000 free_needed_filtees(Needed_Entry *n)
2002 Needed_Entry *needed, *needed1;
2004 for (needed = n; needed != NULL; needed = needed->next) {
2005 if (needed->obj != NULL) {
2006 dlclose(needed->obj);
2010 for (needed = n; needed != NULL; needed = needed1) {
2011 needed1 = needed->next;
2017 unload_filtees(Obj_Entry *obj)
2020 free_needed_filtees(obj->needed_filtees);
2021 obj->needed_filtees = NULL;
2022 free_needed_filtees(obj->needed_aux_filtees);
2023 obj->needed_aux_filtees = NULL;
2024 obj->filtees_loaded = false;
2028 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2029 RtldLockState *lockstate)
2032 for (; needed != NULL; needed = needed->next) {
2033 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2034 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2035 RTLD_LOCAL, lockstate);
2040 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2043 lock_restart_for_upgrade(lockstate);
2044 if (!obj->filtees_loaded) {
2045 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2046 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2047 obj->filtees_loaded = true;
2052 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2056 for (; needed != NULL; needed = needed->next) {
2057 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2058 flags & ~RTLD_LO_NOLOAD);
2059 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2066 * Given a shared object, traverse its list of needed objects, and load
2067 * each of them. Returns 0 on success. Generates an error message and
2068 * returns -1 on failure.
2071 load_needed_objects(Obj_Entry *first, int flags)
2075 for (obj = first; obj != NULL; obj = obj->next) {
2076 if (process_needed(obj, obj->needed, flags) == -1)
2083 load_preload_objects(void)
2085 char *p = ld_preload;
2087 static const char delim[] = " \t:;";
2092 p += strspn(p, delim);
2093 while (*p != '\0') {
2094 size_t len = strcspn(p, delim);
2099 obj = load_object(p, -1, NULL, 0);
2101 return -1; /* XXX - cleanup */
2102 obj->z_interpose = true;
2105 p += strspn(p, delim);
2107 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2112 printable_path(const char *path)
2115 return (path == NULL ? "<unknown>" : path);
2119 * Load a shared object into memory, if it is not already loaded. The
2120 * object may be specified by name or by user-supplied file descriptor
2121 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2124 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2128 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2136 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2137 if (object_match_name(obj, name))
2141 path = find_library(name, refobj);
2148 * If we didn't find a match by pathname, or the name is not
2149 * supplied, open the file and check again by device and inode.
2150 * This avoids false mismatches caused by multiple links or ".."
2153 * To avoid a race, we open the file and use fstat() rather than
2158 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2159 _rtld_error("Cannot open \"%s\"", path);
2164 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2166 _rtld_error("Cannot dup fd");
2171 if (fstat(fd, &sb) == -1) {
2172 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2177 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2178 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2180 if (obj != NULL && name != NULL) {
2181 object_add_name(obj, name);
2186 if (flags & RTLD_LO_NOLOAD) {
2192 /* First use of this object, so we must map it in */
2193 obj = do_load_object(fd, name, path, &sb, flags);
2202 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2209 * but first, make sure that environment variables haven't been
2210 * used to circumvent the noexec flag on a filesystem.
2212 if (dangerous_ld_env) {
2213 if (fstatfs(fd, &fs) != 0) {
2214 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2217 if (fs.f_flags & MNT_NOEXEC) {
2218 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2222 dbg("loading \"%s\"", printable_path(path));
2223 obj = map_object(fd, printable_path(path), sbp);
2228 * If DT_SONAME is present in the object, digest_dynamic2 already
2229 * added it to the object names.
2232 object_add_name(obj, name);
2234 digest_dynamic(obj, 0);
2235 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2236 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2237 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2239 dbg("refusing to load non-loadable \"%s\"", obj->path);
2240 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2241 munmap(obj->mapbase, obj->mapsize);
2246 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2248 obj_tail = &obj->next;
2251 linkmap_add(obj); /* for GDB & dlinfo() */
2252 max_stack_flags |= obj->stack_flags;
2254 dbg(" %p .. %p: %s", obj->mapbase,
2255 obj->mapbase + obj->mapsize - 1, obj->path);
2257 dbg(" WARNING: %s has impure text", obj->path);
2258 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2265 obj_from_addr(const void *addr)
2269 for (obj = obj_list; obj != NULL; obj = obj->next) {
2270 if (addr < (void *) obj->mapbase)
2272 if (addr < (void *) (obj->mapbase + obj->mapsize))
2281 Elf_Addr *preinit_addr;
2284 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2285 if (preinit_addr == NULL)
2288 for (index = 0; index < obj_main->preinit_array_num; index++) {
2289 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2290 dbg("calling preinit function for %s at %p", obj_main->path,
2291 (void *)preinit_addr[index]);
2292 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2293 0, 0, obj_main->path);
2294 call_init_pointer(obj_main, preinit_addr[index]);
2300 * Call the finalization functions for each of the objects in "list"
2301 * belonging to the DAG of "root" and referenced once. If NULL "root"
2302 * is specified, every finalization function will be called regardless
2303 * of the reference count and the list elements won't be freed. All of
2304 * the objects are expected to have non-NULL fini functions.
2307 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2311 Elf_Addr *fini_addr;
2314 assert(root == NULL || root->refcount == 1);
2317 * Preserve the current error message since a fini function might
2318 * call into the dynamic linker and overwrite it.
2320 saved_msg = errmsg_save();
2322 STAILQ_FOREACH(elm, list, link) {
2323 if (root != NULL && (elm->obj->refcount != 1 ||
2324 objlist_find(&root->dagmembers, elm->obj) == NULL))
2326 /* Remove object from fini list to prevent recursive invocation. */
2327 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2329 * XXX: If a dlopen() call references an object while the
2330 * fini function is in progress, we might end up trying to
2331 * unload the referenced object in dlclose() or the object
2332 * won't be unloaded although its fini function has been
2335 lock_release(rtld_bind_lock, lockstate);
2338 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2339 * When this happens, DT_FINI_ARRAY is processed first.
2341 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2342 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2343 for (index = elm->obj->fini_array_num - 1; index >= 0;
2345 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2346 dbg("calling fini function for %s at %p",
2347 elm->obj->path, (void *)fini_addr[index]);
2348 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2349 (void *)fini_addr[index], 0, 0, elm->obj->path);
2350 call_initfini_pointer(elm->obj, fini_addr[index]);
2354 if (elm->obj->fini != (Elf_Addr)NULL) {
2355 dbg("calling fini function for %s at %p", elm->obj->path,
2356 (void *)elm->obj->fini);
2357 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2358 0, 0, elm->obj->path);
2359 call_initfini_pointer(elm->obj, elm->obj->fini);
2361 wlock_acquire(rtld_bind_lock, lockstate);
2362 /* No need to free anything if process is going down. */
2366 * We must restart the list traversal after every fini call
2367 * because a dlclose() call from the fini function or from
2368 * another thread might have modified the reference counts.
2372 } while (elm != NULL);
2373 errmsg_restore(saved_msg);
2377 * Call the initialization functions for each of the objects in
2378 * "list". All of the objects are expected to have non-NULL init
2382 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2387 Elf_Addr *init_addr;
2391 * Clean init_scanned flag so that objects can be rechecked and
2392 * possibly initialized earlier if any of vectors called below
2393 * cause the change by using dlopen.
2395 for (obj = obj_list; obj != NULL; obj = obj->next)
2396 obj->init_scanned = false;
2399 * Preserve the current error message since an init function might
2400 * call into the dynamic linker and overwrite it.
2402 saved_msg = errmsg_save();
2403 STAILQ_FOREACH(elm, list, link) {
2404 if (elm->obj->init_done) /* Initialized early. */
2407 * Race: other thread might try to use this object before current
2408 * one completes the initilization. Not much can be done here
2409 * without better locking.
2411 elm->obj->init_done = true;
2412 lock_release(rtld_bind_lock, lockstate);
2415 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2416 * When this happens, DT_INIT is processed first.
2418 if (elm->obj->init != (Elf_Addr)NULL) {
2419 dbg("calling init function for %s at %p", elm->obj->path,
2420 (void *)elm->obj->init);
2421 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2422 0, 0, elm->obj->path);
2423 call_initfini_pointer(elm->obj, elm->obj->init);
2425 init_addr = (Elf_Addr *)elm->obj->init_array;
2426 if (init_addr != NULL) {
2427 for (index = 0; index < elm->obj->init_array_num; index++) {
2428 if (init_addr[index] != 0 && init_addr[index] != 1) {
2429 dbg("calling init function for %s at %p", elm->obj->path,
2430 (void *)init_addr[index]);
2431 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2432 (void *)init_addr[index], 0, 0, elm->obj->path);
2433 call_init_pointer(elm->obj, init_addr[index]);
2437 wlock_acquire(rtld_bind_lock, lockstate);
2439 errmsg_restore(saved_msg);
2443 objlist_clear(Objlist *list)
2447 while (!STAILQ_EMPTY(list)) {
2448 elm = STAILQ_FIRST(list);
2449 STAILQ_REMOVE_HEAD(list, link);
2454 static Objlist_Entry *
2455 objlist_find(Objlist *list, const Obj_Entry *obj)
2459 STAILQ_FOREACH(elm, list, link)
2460 if (elm->obj == obj)
2466 objlist_init(Objlist *list)
2472 objlist_push_head(Objlist *list, Obj_Entry *obj)
2476 elm = NEW(Objlist_Entry);
2478 STAILQ_INSERT_HEAD(list, elm, link);
2482 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2486 elm = NEW(Objlist_Entry);
2488 STAILQ_INSERT_TAIL(list, elm, link);
2492 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2494 Objlist_Entry *elm, *listelm;
2496 STAILQ_FOREACH(listelm, list, link) {
2497 if (listelm->obj == listobj)
2500 elm = NEW(Objlist_Entry);
2502 if (listelm != NULL)
2503 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2505 STAILQ_INSERT_TAIL(list, elm, link);
2509 objlist_remove(Objlist *list, Obj_Entry *obj)
2513 if ((elm = objlist_find(list, obj)) != NULL) {
2514 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2520 * Relocate dag rooted in the specified object.
2521 * Returns 0 on success, or -1 on failure.
2525 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2526 int flags, RtldLockState *lockstate)
2532 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2533 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2542 * Relocate single object.
2543 * Returns 0 on success, or -1 on failure.
2546 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2547 int flags, RtldLockState *lockstate)
2552 obj->relocated = true;
2554 dbg("relocating \"%s\"", obj->path);
2556 if (obj->symtab == NULL || obj->strtab == NULL ||
2557 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2558 _rtld_error("%s: Shared object has no run-time symbol table",
2564 /* There are relocations to the write-protected text segment. */
2565 if (mprotect(obj->mapbase, obj->textsize,
2566 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2567 _rtld_error("%s: Cannot write-enable text segment: %s",
2568 obj->path, rtld_strerror(errno));
2573 /* Process the non-PLT non-IFUNC relocations. */
2574 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2577 if (obj->textrel) { /* Re-protected the text segment. */
2578 if (mprotect(obj->mapbase, obj->textsize,
2579 PROT_READ|PROT_EXEC) == -1) {
2580 _rtld_error("%s: Cannot write-protect text segment: %s",
2581 obj->path, rtld_strerror(errno));
2586 /* Set the special PLT or GOT entries. */
2589 /* Process the PLT relocations. */
2590 if (reloc_plt(obj) == -1)
2592 /* Relocate the jump slots if we are doing immediate binding. */
2593 if (obj->bind_now || bind_now)
2594 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2598 * Process the non-PLT IFUNC relocations. The relocations are
2599 * processed in two phases, because IFUNC resolvers may
2600 * reference other symbols, which must be readily processed
2601 * before resolvers are called.
2603 if (obj->non_plt_gnu_ifunc &&
2604 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2607 if (obj->relro_size > 0) {
2608 if (mprotect(obj->relro_page, obj->relro_size,
2610 _rtld_error("%s: Cannot enforce relro protection: %s",
2611 obj->path, rtld_strerror(errno));
2617 * Set up the magic number and version in the Obj_Entry. These
2618 * were checked in the crt1.o from the original ElfKit, so we
2619 * set them for backward compatibility.
2621 obj->magic = RTLD_MAGIC;
2622 obj->version = RTLD_VERSION;
2628 * Relocate newly-loaded shared objects. The argument is a pointer to
2629 * the Obj_Entry for the first such object. All objects from the first
2630 * to the end of the list of objects are relocated. Returns 0 on success,
2634 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2635 int flags, RtldLockState *lockstate)
2640 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2641 error = relocate_object(obj, bind_now, rtldobj, flags,
2650 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2651 * referencing STT_GNU_IFUNC symbols is postponed till the other
2652 * relocations are done. The indirect functions specified as
2653 * ifunc are allowed to call other symbols, so we need to have
2654 * objects relocated before asking for resolution from indirects.
2656 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2657 * instead of the usual lazy handling of PLT slots. It is
2658 * consistent with how GNU does it.
2661 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2662 RtldLockState *lockstate)
2664 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2666 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2667 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2673 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2674 RtldLockState *lockstate)
2678 for (obj = first; obj != NULL; obj = obj->next) {
2679 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2686 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2687 RtldLockState *lockstate)
2691 STAILQ_FOREACH(elm, list, link) {
2692 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2700 * Cleanup procedure. It will be called (by the atexit mechanism) just
2701 * before the process exits.
2706 RtldLockState lockstate;
2708 wlock_acquire(rtld_bind_lock, &lockstate);
2710 objlist_call_fini(&list_fini, NULL, &lockstate);
2711 /* No need to remove the items from the list, since we are exiting. */
2712 if (!libmap_disable)
2714 lock_release(rtld_bind_lock, &lockstate);
2718 * Iterate over a search path, translate each element, and invoke the
2719 * callback on the result.
2722 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2728 path += strspn(path, ":;");
2729 while (*path != '\0') {
2733 len = strcspn(path, ":;");
2734 trans = lm_findn(NULL, path, len);
2736 res = callback(trans, strlen(trans), arg);
2738 res = callback(path, len, arg);
2744 path += strspn(path, ":;");
2750 struct try_library_args {
2758 try_library_path(const char *dir, size_t dirlen, void *param)
2760 struct try_library_args *arg;
2763 if (*dir == '/' || trust) {
2766 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2769 pathname = arg->buffer;
2770 strncpy(pathname, dir, dirlen);
2771 pathname[dirlen] = '/';
2772 strcpy(pathname + dirlen + 1, arg->name);
2774 dbg(" Trying \"%s\"", pathname);
2775 if (access(pathname, F_OK) == 0) { /* We found it */
2776 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2777 strcpy(pathname, arg->buffer);
2785 search_library_path(const char *name, const char *path)
2788 struct try_library_args arg;
2794 arg.namelen = strlen(name);
2795 arg.buffer = xmalloc(PATH_MAX);
2796 arg.buflen = PATH_MAX;
2798 p = path_enumerate(path, try_library_path, &arg);
2806 dlclose(void *handle)
2809 RtldLockState lockstate;
2811 wlock_acquire(rtld_bind_lock, &lockstate);
2812 root = dlcheck(handle);
2814 lock_release(rtld_bind_lock, &lockstate);
2817 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2820 /* Unreference the object and its dependencies. */
2821 root->dl_refcount--;
2823 if (root->refcount == 1) {
2825 * The object will be no longer referenced, so we must unload it.
2826 * First, call the fini functions.
2828 objlist_call_fini(&list_fini, root, &lockstate);
2832 /* Finish cleaning up the newly-unreferenced objects. */
2833 GDB_STATE(RT_DELETE,&root->linkmap);
2834 unload_object(root);
2835 GDB_STATE(RT_CONSISTENT,NULL);
2839 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2840 lock_release(rtld_bind_lock, &lockstate);
2847 char *msg = error_message;
2848 error_message = NULL;
2853 * This function is deprecated and has no effect.
2856 dllockinit(void *context,
2857 void *(*lock_create)(void *context),
2858 void (*rlock_acquire)(void *lock),
2859 void (*wlock_acquire)(void *lock),
2860 void (*lock_release)(void *lock),
2861 void (*lock_destroy)(void *lock),
2862 void (*context_destroy)(void *context))
2864 static void *cur_context;
2865 static void (*cur_context_destroy)(void *);
2867 /* Just destroy the context from the previous call, if necessary. */
2868 if (cur_context_destroy != NULL)
2869 cur_context_destroy(cur_context);
2870 cur_context = context;
2871 cur_context_destroy = context_destroy;
2875 dlopen(const char *name, int mode)
2878 return (rtld_dlopen(name, -1, mode));
2882 fdlopen(int fd, int mode)
2885 return (rtld_dlopen(NULL, fd, mode));
2889 rtld_dlopen(const char *name, int fd, int mode)
2891 RtldLockState lockstate;
2894 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2895 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2896 if (ld_tracing != NULL) {
2897 rlock_acquire(rtld_bind_lock, &lockstate);
2898 if (sigsetjmp(lockstate.env, 0) != 0)
2899 lock_upgrade(rtld_bind_lock, &lockstate);
2900 environ = (char **)*get_program_var_addr("environ", &lockstate);
2901 lock_release(rtld_bind_lock, &lockstate);
2903 lo_flags = RTLD_LO_DLOPEN;
2904 if (mode & RTLD_NODELETE)
2905 lo_flags |= RTLD_LO_NODELETE;
2906 if (mode & RTLD_NOLOAD)
2907 lo_flags |= RTLD_LO_NOLOAD;
2908 if (ld_tracing != NULL)
2909 lo_flags |= RTLD_LO_TRACE;
2911 return (dlopen_object(name, fd, obj_main, lo_flags,
2912 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2916 dlopen_cleanup(Obj_Entry *obj)
2921 if (obj->refcount == 0)
2926 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2927 int mode, RtldLockState *lockstate)
2929 Obj_Entry **old_obj_tail;
2932 RtldLockState mlockstate;
2935 objlist_init(&initlist);
2937 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2938 wlock_acquire(rtld_bind_lock, &mlockstate);
2939 lockstate = &mlockstate;
2941 GDB_STATE(RT_ADD,NULL);
2943 old_obj_tail = obj_tail;
2945 if (name == NULL && fd == -1) {
2949 obj = load_object(name, fd, refobj, lo_flags);
2954 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2955 objlist_push_tail(&list_global, obj);
2956 if (*old_obj_tail != NULL) { /* We loaded something new. */
2957 assert(*old_obj_tail == obj);
2958 result = load_needed_objects(obj,
2959 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2963 result = rtld_verify_versions(&obj->dagmembers);
2964 if (result != -1 && ld_tracing)
2966 if (result == -1 || relocate_object_dag(obj,
2967 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2968 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2970 dlopen_cleanup(obj);
2972 } else if (lo_flags & RTLD_LO_EARLY) {
2974 * Do not call the init functions for early loaded
2975 * filtees. The image is still not initialized enough
2978 * Our object is found by the global object list and
2979 * will be ordered among all init calls done right
2980 * before transferring control to main.
2983 /* Make list of init functions to call. */
2984 initlist_add_objects(obj, &obj->next, &initlist);
2987 * Process all no_delete or global objects here, given
2988 * them own DAGs to prevent their dependencies from being
2989 * unloaded. This has to be done after we have loaded all
2990 * of the dependencies, so that we do not miss any.
2996 * Bump the reference counts for objects on this DAG. If
2997 * this is the first dlopen() call for the object that was
2998 * already loaded as a dependency, initialize the dag
3004 if ((lo_flags & RTLD_LO_TRACE) != 0)
3007 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3008 obj->z_nodelete) && !obj->ref_nodel) {
3009 dbg("obj %s nodelete", obj->path);
3011 obj->z_nodelete = obj->ref_nodel = true;
3015 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3017 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3019 if (!(lo_flags & RTLD_LO_EARLY)) {
3020 map_stacks_exec(lockstate);
3023 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3024 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3026 objlist_clear(&initlist);
3027 dlopen_cleanup(obj);
3028 if (lockstate == &mlockstate)
3029 lock_release(rtld_bind_lock, lockstate);
3033 if (!(lo_flags & RTLD_LO_EARLY)) {
3034 /* Call the init functions. */
3035 objlist_call_init(&initlist, lockstate);
3037 objlist_clear(&initlist);
3038 if (lockstate == &mlockstate)
3039 lock_release(rtld_bind_lock, lockstate);
3042 trace_loaded_objects(obj);
3043 if (lockstate == &mlockstate)
3044 lock_release(rtld_bind_lock, lockstate);
3049 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3053 const Obj_Entry *obj, *defobj;
3056 RtldLockState lockstate;
3065 symlook_init(&req, name);
3067 req.flags = flags | SYMLOOK_IN_PLT;
3068 req.lockstate = &lockstate;
3070 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3071 rlock_acquire(rtld_bind_lock, &lockstate);
3072 if (sigsetjmp(lockstate.env, 0) != 0)
3073 lock_upgrade(rtld_bind_lock, &lockstate);
3074 if (handle == NULL || handle == RTLD_NEXT ||
3075 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3077 if ((obj = obj_from_addr(retaddr)) == NULL) {
3078 _rtld_error("Cannot determine caller's shared object");
3079 lock_release(rtld_bind_lock, &lockstate);
3080 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3083 if (handle == NULL) { /* Just the caller's shared object. */
3084 res = symlook_obj(&req, obj);
3087 defobj = req.defobj_out;
3089 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3090 handle == RTLD_SELF) { /* ... caller included */
3091 if (handle == RTLD_NEXT)
3093 for (; obj != NULL; obj = obj->next) {
3094 res = symlook_obj(&req, obj);
3097 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3099 defobj = req.defobj_out;
3100 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3106 * Search the dynamic linker itself, and possibly resolve the
3107 * symbol from there. This is how the application links to
3108 * dynamic linker services such as dlopen.
3110 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3111 res = symlook_obj(&req, &obj_rtld);
3114 defobj = req.defobj_out;
3118 assert(handle == RTLD_DEFAULT);
3119 res = symlook_default(&req, obj);
3121 defobj = req.defobj_out;
3126 if ((obj = dlcheck(handle)) == NULL) {
3127 lock_release(rtld_bind_lock, &lockstate);
3128 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3132 donelist_init(&donelist);
3133 if (obj->mainprog) {
3134 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3135 res = symlook_global(&req, &donelist);
3138 defobj = req.defobj_out;
3141 * Search the dynamic linker itself, and possibly resolve the
3142 * symbol from there. This is how the application links to
3143 * dynamic linker services such as dlopen.
3145 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3146 res = symlook_obj(&req, &obj_rtld);
3149 defobj = req.defobj_out;
3154 /* Search the whole DAG rooted at the given object. */
3155 res = symlook_list(&req, &obj->dagmembers, &donelist);
3158 defobj = req.defobj_out;
3164 lock_release(rtld_bind_lock, &lockstate);
3167 * The value required by the caller is derived from the value
3168 * of the symbol. For the ia64 architecture, we need to
3169 * construct a function descriptor which the caller can use to
3170 * call the function with the right 'gp' value. For other
3171 * architectures and for non-functions, the value is simply
3172 * the relocated value of the symbol.
3174 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3175 sym = make_function_pointer(def, defobj);
3176 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3177 sym = rtld_resolve_ifunc(defobj, def);
3178 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3180 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3182 ti.ti_module = defobj->tlsindex;
3183 ti.ti_offset = def->st_value;
3184 sym = __tls_get_addr(&ti);
3187 sym = defobj->relocbase + def->st_value;
3188 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3192 _rtld_error("Undefined symbol \"%s\"", name);
3193 lock_release(rtld_bind_lock, &lockstate);
3194 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3199 dlsym(void *handle, const char *name)
3201 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3206 dlfunc(void *handle, const char *name)
3213 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3219 dlvsym(void *handle, const char *name, const char *version)
3223 ventry.name = version;
3225 ventry.hash = elf_hash(version);
3227 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3232 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3234 const Obj_Entry *obj;
3235 RtldLockState lockstate;
3237 rlock_acquire(rtld_bind_lock, &lockstate);
3238 obj = obj_from_addr(addr);
3240 _rtld_error("No shared object contains address");
3241 lock_release(rtld_bind_lock, &lockstate);
3244 rtld_fill_dl_phdr_info(obj, phdr_info);
3245 lock_release(rtld_bind_lock, &lockstate);
3250 dladdr(const void *addr, Dl_info *info)
3252 const Obj_Entry *obj;
3255 unsigned long symoffset;
3256 RtldLockState lockstate;
3258 rlock_acquire(rtld_bind_lock, &lockstate);
3259 obj = obj_from_addr(addr);
3261 _rtld_error("No shared object contains address");
3262 lock_release(rtld_bind_lock, &lockstate);
3265 info->dli_fname = obj->path;
3266 info->dli_fbase = obj->mapbase;
3267 info->dli_saddr = (void *)0;
3268 info->dli_sname = NULL;
3271 * Walk the symbol list looking for the symbol whose address is
3272 * closest to the address sent in.
3274 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3275 def = obj->symtab + symoffset;
3278 * For skip the symbol if st_shndx is either SHN_UNDEF or
3281 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3285 * If the symbol is greater than the specified address, or if it
3286 * is further away from addr than the current nearest symbol,
3289 symbol_addr = obj->relocbase + def->st_value;
3290 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3293 /* Update our idea of the nearest symbol. */
3294 info->dli_sname = obj->strtab + def->st_name;
3295 info->dli_saddr = symbol_addr;
3298 if (info->dli_saddr == addr)
3301 lock_release(rtld_bind_lock, &lockstate);
3306 dlinfo(void *handle, int request, void *p)
3308 const Obj_Entry *obj;
3309 RtldLockState lockstate;
3312 rlock_acquire(rtld_bind_lock, &lockstate);
3314 if (handle == NULL || handle == RTLD_SELF) {
3317 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3318 if ((obj = obj_from_addr(retaddr)) == NULL)
3319 _rtld_error("Cannot determine caller's shared object");
3321 obj = dlcheck(handle);
3324 lock_release(rtld_bind_lock, &lockstate);
3330 case RTLD_DI_LINKMAP:
3331 *((struct link_map const **)p) = &obj->linkmap;
3333 case RTLD_DI_ORIGIN:
3334 error = rtld_dirname(obj->path, p);
3337 case RTLD_DI_SERINFOSIZE:
3338 case RTLD_DI_SERINFO:
3339 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3343 _rtld_error("Invalid request %d passed to dlinfo()", request);
3347 lock_release(rtld_bind_lock, &lockstate);
3353 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3356 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3357 phdr_info->dlpi_name = obj->path;
3358 phdr_info->dlpi_phdr = obj->phdr;
3359 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3360 phdr_info->dlpi_tls_modid = obj->tlsindex;
3361 phdr_info->dlpi_tls_data = obj->tlsinit;
3362 phdr_info->dlpi_adds = obj_loads;
3363 phdr_info->dlpi_subs = obj_loads - obj_count;
3367 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3369 struct dl_phdr_info phdr_info;
3370 const Obj_Entry *obj;
3371 RtldLockState bind_lockstate, phdr_lockstate;
3374 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3375 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3379 for (obj = obj_list; obj != NULL; obj = obj->next) {
3380 rtld_fill_dl_phdr_info(obj, &phdr_info);
3381 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3385 lock_release(rtld_bind_lock, &bind_lockstate);
3386 lock_release(rtld_phdr_lock, &phdr_lockstate);
3392 fill_search_info(const char *dir, size_t dirlen, void *param)
3394 struct fill_search_info_args *arg;
3398 if (arg->request == RTLD_DI_SERINFOSIZE) {
3399 arg->serinfo->dls_cnt ++;
3400 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3402 struct dl_serpath *s_entry;
3404 s_entry = arg->serpath;
3405 s_entry->dls_name = arg->strspace;
3406 s_entry->dls_flags = arg->flags;
3408 strncpy(arg->strspace, dir, dirlen);
3409 arg->strspace[dirlen] = '\0';
3411 arg->strspace += dirlen + 1;
3419 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3421 struct dl_serinfo _info;
3422 struct fill_search_info_args args;
3424 args.request = RTLD_DI_SERINFOSIZE;
3425 args.serinfo = &_info;
3427 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3430 path_enumerate(obj->rpath, fill_search_info, &args);
3431 path_enumerate(ld_library_path, fill_search_info, &args);
3432 path_enumerate(obj->runpath, fill_search_info, &args);
3433 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3434 if (!obj->z_nodeflib)
3435 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3438 if (request == RTLD_DI_SERINFOSIZE) {
3439 info->dls_size = _info.dls_size;
3440 info->dls_cnt = _info.dls_cnt;
3444 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3445 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3449 args.request = RTLD_DI_SERINFO;
3450 args.serinfo = info;
3451 args.serpath = &info->dls_serpath[0];
3452 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3454 args.flags = LA_SER_RUNPATH;
3455 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3458 args.flags = LA_SER_LIBPATH;
3459 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3462 args.flags = LA_SER_RUNPATH;
3463 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3466 args.flags = LA_SER_CONFIG;
3467 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3471 args.flags = LA_SER_DEFAULT;
3472 if (!obj->z_nodeflib &&
3473 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3479 rtld_dirname(const char *path, char *bname)
3483 /* Empty or NULL string gets treated as "." */
3484 if (path == NULL || *path == '\0') {
3490 /* Strip trailing slashes */
3491 endp = path + strlen(path) - 1;
3492 while (endp > path && *endp == '/')
3495 /* Find the start of the dir */
3496 while (endp > path && *endp != '/')
3499 /* Either the dir is "/" or there are no slashes */
3501 bname[0] = *endp == '/' ? '/' : '.';
3507 } while (endp > path && *endp == '/');
3510 if (endp - path + 2 > PATH_MAX)
3512 _rtld_error("Filename is too long: %s", path);
3516 strncpy(bname, path, endp - path + 1);
3517 bname[endp - path + 1] = '\0';
3522 rtld_dirname_abs(const char *path, char *base)
3526 if (realpath(path, base) == NULL)
3528 dbg("%s -> %s", path, base);
3529 last = strrchr(base, '/');
3538 linkmap_add(Obj_Entry *obj)
3540 struct link_map *l = &obj->linkmap;
3541 struct link_map *prev;
3543 obj->linkmap.l_name = obj->path;
3544 obj->linkmap.l_addr = obj->mapbase;
3545 obj->linkmap.l_ld = obj->dynamic;
3547 /* GDB needs load offset on MIPS to use the symbols */
3548 obj->linkmap.l_offs = obj->relocbase;
3551 if (r_debug.r_map == NULL) {
3557 * Scan to the end of the list, but not past the entry for the
3558 * dynamic linker, which we want to keep at the very end.
3560 for (prev = r_debug.r_map;
3561 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3562 prev = prev->l_next)
3565 /* Link in the new entry. */
3567 l->l_next = prev->l_next;
3568 if (l->l_next != NULL)
3569 l->l_next->l_prev = l;
3574 linkmap_delete(Obj_Entry *obj)
3576 struct link_map *l = &obj->linkmap;
3578 if (l->l_prev == NULL) {
3579 if ((r_debug.r_map = l->l_next) != NULL)
3580 l->l_next->l_prev = NULL;
3584 if ((l->l_prev->l_next = l->l_next) != NULL)
3585 l->l_next->l_prev = l->l_prev;
3589 * Function for the debugger to set a breakpoint on to gain control.
3591 * The two parameters allow the debugger to easily find and determine
3592 * what the runtime loader is doing and to whom it is doing it.
3594 * When the loadhook trap is hit (r_debug_state, set at program
3595 * initialization), the arguments can be found on the stack:
3597 * +8 struct link_map *m
3598 * +4 struct r_debug *rd
3602 r_debug_state(struct r_debug* rd, struct link_map *m)
3605 * The following is a hack to force the compiler to emit calls to
3606 * this function, even when optimizing. If the function is empty,
3607 * the compiler is not obliged to emit any code for calls to it,
3608 * even when marked __noinline. However, gdb depends on those
3611 __compiler_membar();
3615 * A function called after init routines have completed. This can be used to
3616 * break before a program's entry routine is called, and can be used when
3617 * main is not available in the symbol table.
3620 _r_debug_postinit(struct link_map *m)
3623 /* See r_debug_state(). */
3624 __compiler_membar();
3628 * Get address of the pointer variable in the main program.
3629 * Prefer non-weak symbol over the weak one.
3631 static const void **
3632 get_program_var_addr(const char *name, RtldLockState *lockstate)
3637 symlook_init(&req, name);
3638 req.lockstate = lockstate;
3639 donelist_init(&donelist);
3640 if (symlook_global(&req, &donelist) != 0)
3642 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3643 return ((const void **)make_function_pointer(req.sym_out,
3645 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3646 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3648 return ((const void **)(req.defobj_out->relocbase +
3649 req.sym_out->st_value));
3653 * Set a pointer variable in the main program to the given value. This
3654 * is used to set key variables such as "environ" before any of the
3655 * init functions are called.
3658 set_program_var(const char *name, const void *value)
3662 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3663 dbg("\"%s\": *%p <-- %p", name, addr, value);
3669 * Search the global objects, including dependencies and main object,
3670 * for the given symbol.
3673 symlook_global(SymLook *req, DoneList *donelist)
3676 const Objlist_Entry *elm;
3679 symlook_init_from_req(&req1, req);
3681 /* Search all objects loaded at program start up. */
3682 if (req->defobj_out == NULL ||
3683 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3684 res = symlook_list(&req1, &list_main, donelist);
3685 if (res == 0 && (req->defobj_out == NULL ||
3686 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3687 req->sym_out = req1.sym_out;
3688 req->defobj_out = req1.defobj_out;
3689 assert(req->defobj_out != NULL);
3693 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3694 STAILQ_FOREACH(elm, &list_global, link) {
3695 if (req->defobj_out != NULL &&
3696 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3698 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3699 if (res == 0 && (req->defobj_out == NULL ||
3700 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3701 req->sym_out = req1.sym_out;
3702 req->defobj_out = req1.defobj_out;
3703 assert(req->defobj_out != NULL);
3707 return (req->sym_out != NULL ? 0 : ESRCH);
3711 * Given a symbol name in a referencing object, find the corresponding
3712 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3713 * no definition was found. Returns a pointer to the Obj_Entry of the
3714 * defining object via the reference parameter DEFOBJ_OUT.
3717 symlook_default(SymLook *req, const Obj_Entry *refobj)
3720 const Objlist_Entry *elm;
3724 donelist_init(&donelist);
3725 symlook_init_from_req(&req1, req);
3727 /* Look first in the referencing object if linked symbolically. */
3728 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3729 res = symlook_obj(&req1, refobj);
3731 req->sym_out = req1.sym_out;
3732 req->defobj_out = req1.defobj_out;
3733 assert(req->defobj_out != NULL);
3737 symlook_global(req, &donelist);
3739 /* Search all dlopened DAGs containing the referencing object. */
3740 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3741 if (req->sym_out != NULL &&
3742 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3744 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3745 if (res == 0 && (req->sym_out == NULL ||
3746 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3747 req->sym_out = req1.sym_out;
3748 req->defobj_out = req1.defobj_out;
3749 assert(req->defobj_out != NULL);
3754 * Search the dynamic linker itself, and possibly resolve the
3755 * symbol from there. This is how the application links to
3756 * dynamic linker services such as dlopen.
3758 if (req->sym_out == NULL ||
3759 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3760 res = symlook_obj(&req1, &obj_rtld);
3762 req->sym_out = req1.sym_out;
3763 req->defobj_out = req1.defobj_out;
3764 assert(req->defobj_out != NULL);
3768 return (req->sym_out != NULL ? 0 : ESRCH);
3772 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3775 const Obj_Entry *defobj;
3776 const Objlist_Entry *elm;
3782 STAILQ_FOREACH(elm, objlist, link) {
3783 if (donelist_check(dlp, elm->obj))
3785 symlook_init_from_req(&req1, req);
3786 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3787 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3789 defobj = req1.defobj_out;
3790 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3797 req->defobj_out = defobj;
3804 * Search the chain of DAGS cointed to by the given Needed_Entry
3805 * for a symbol of the given name. Each DAG is scanned completely
3806 * before advancing to the next one. Returns a pointer to the symbol,
3807 * or NULL if no definition was found.
3810 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3813 const Needed_Entry *n;
3814 const Obj_Entry *defobj;
3820 symlook_init_from_req(&req1, req);
3821 for (n = needed; n != NULL; n = n->next) {
3822 if (n->obj == NULL ||
3823 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3825 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3827 defobj = req1.defobj_out;
3828 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3834 req->defobj_out = defobj;
3841 * Search the symbol table of a single shared object for a symbol of
3842 * the given name and version, if requested. Returns a pointer to the
3843 * symbol, or NULL if no definition was found. If the object is
3844 * filter, return filtered symbol from filtee.
3846 * The symbol's hash value is passed in for efficiency reasons; that
3847 * eliminates many recomputations of the hash value.
3850 symlook_obj(SymLook *req, const Obj_Entry *obj)
3854 int flags, res, mres;
3857 * If there is at least one valid hash at this point, we prefer to
3858 * use the faster GNU version if available.
3860 if (obj->valid_hash_gnu)
3861 mres = symlook_obj1_gnu(req, obj);
3862 else if (obj->valid_hash_sysv)
3863 mres = symlook_obj1_sysv(req, obj);
3868 if (obj->needed_filtees != NULL) {
3869 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3870 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3871 donelist_init(&donelist);
3872 symlook_init_from_req(&req1, req);
3873 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3875 req->sym_out = req1.sym_out;
3876 req->defobj_out = req1.defobj_out;
3880 if (obj->needed_aux_filtees != NULL) {
3881 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3882 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3883 donelist_init(&donelist);
3884 symlook_init_from_req(&req1, req);
3885 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3887 req->sym_out = req1.sym_out;
3888 req->defobj_out = req1.defobj_out;
3896 /* Symbol match routine common to both hash functions */
3898 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3899 const unsigned long symnum)
3902 const Elf_Sym *symp;
3905 symp = obj->symtab + symnum;
3906 strp = obj->strtab + symp->st_name;
3908 switch (ELF_ST_TYPE(symp->st_info)) {
3914 if (symp->st_value == 0)
3918 if (symp->st_shndx != SHN_UNDEF)
3921 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3922 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3929 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3932 if (req->ventry == NULL) {
3933 if (obj->versyms != NULL) {
3934 verndx = VER_NDX(obj->versyms[symnum]);
3935 if (verndx > obj->vernum) {
3937 "%s: symbol %s references wrong version %d",
3938 obj->path, obj->strtab + symnum, verndx);
3942 * If we are not called from dlsym (i.e. this
3943 * is a normal relocation from unversioned
3944 * binary), accept the symbol immediately if
3945 * it happens to have first version after this
3946 * shared object became versioned. Otherwise,
3947 * if symbol is versioned and not hidden,
3948 * remember it. If it is the only symbol with
3949 * this name exported by the shared object, it
3950 * will be returned as a match by the calling
3951 * function. If symbol is global (verndx < 2)
3952 * accept it unconditionally.
3954 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3955 verndx == VER_NDX_GIVEN) {
3956 result->sym_out = symp;
3959 else if (verndx >= VER_NDX_GIVEN) {
3960 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3962 if (result->vsymp == NULL)
3963 result->vsymp = symp;
3969 result->sym_out = symp;
3972 if (obj->versyms == NULL) {
3973 if (object_match_name(obj, req->ventry->name)) {
3974 _rtld_error("%s: object %s should provide version %s "
3975 "for symbol %s", obj_rtld.path, obj->path,
3976 req->ventry->name, obj->strtab + symnum);
3980 verndx = VER_NDX(obj->versyms[symnum]);
3981 if (verndx > obj->vernum) {
3982 _rtld_error("%s: symbol %s references wrong version %d",
3983 obj->path, obj->strtab + symnum, verndx);
3986 if (obj->vertab[verndx].hash != req->ventry->hash ||
3987 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3989 * Version does not match. Look if this is a
3990 * global symbol and if it is not hidden. If
3991 * global symbol (verndx < 2) is available,
3992 * use it. Do not return symbol if we are
3993 * called by dlvsym, because dlvsym looks for
3994 * a specific version and default one is not
3995 * what dlvsym wants.
3997 if ((req->flags & SYMLOOK_DLSYM) ||
3998 (verndx >= VER_NDX_GIVEN) ||
3999 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4003 result->sym_out = symp;
4008 * Search for symbol using SysV hash function.
4009 * obj->buckets is known not to be NULL at this point; the test for this was
4010 * performed with the obj->valid_hash_sysv assignment.
4013 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4015 unsigned long symnum;
4016 Sym_Match_Result matchres;
4018 matchres.sym_out = NULL;
4019 matchres.vsymp = NULL;
4020 matchres.vcount = 0;
4022 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4023 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4024 if (symnum >= obj->nchains)
4025 return (ESRCH); /* Bad object */
4027 if (matched_symbol(req, obj, &matchres, symnum)) {
4028 req->sym_out = matchres.sym_out;
4029 req->defobj_out = obj;
4033 if (matchres.vcount == 1) {
4034 req->sym_out = matchres.vsymp;
4035 req->defobj_out = obj;
4041 /* Search for symbol using GNU hash function */
4043 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4045 Elf_Addr bloom_word;
4046 const Elf32_Word *hashval;
4048 Sym_Match_Result matchres;
4049 unsigned int h1, h2;
4050 unsigned long symnum;
4052 matchres.sym_out = NULL;
4053 matchres.vsymp = NULL;
4054 matchres.vcount = 0;
4056 /* Pick right bitmask word from Bloom filter array */
4057 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4058 obj->maskwords_bm_gnu];
4060 /* Calculate modulus word size of gnu hash and its derivative */
4061 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4062 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4064 /* Filter out the "definitely not in set" queries */
4065 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4068 /* Locate hash chain and corresponding value element*/
4069 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4072 hashval = &obj->chain_zero_gnu[bucket];
4074 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4075 symnum = hashval - obj->chain_zero_gnu;
4076 if (matched_symbol(req, obj, &matchres, symnum)) {
4077 req->sym_out = matchres.sym_out;
4078 req->defobj_out = obj;
4082 } while ((*hashval++ & 1) == 0);
4083 if (matchres.vcount == 1) {
4084 req->sym_out = matchres.vsymp;
4085 req->defobj_out = obj;
4092 trace_loaded_objects(Obj_Entry *obj)
4094 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4097 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4100 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4101 fmt1 = "\t%o => %p (%x)\n";
4103 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4104 fmt2 = "\t%o (%x)\n";
4106 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4108 for (; obj; obj = obj->next) {
4109 Needed_Entry *needed;
4113 if (list_containers && obj->needed != NULL)
4114 rtld_printf("%s:\n", obj->path);
4115 for (needed = obj->needed; needed; needed = needed->next) {
4116 if (needed->obj != NULL) {
4117 if (needed->obj->traced && !list_containers)
4119 needed->obj->traced = true;
4120 path = needed->obj->path;
4124 name = (char *)obj->strtab + needed->name;
4125 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4127 fmt = is_lib ? fmt1 : fmt2;
4128 while ((c = *fmt++) != '\0') {
4154 rtld_putstr(main_local);
4157 rtld_putstr(obj_main->path);
4164 rtld_printf("%d", sodp->sod_major);
4167 rtld_printf("%d", sodp->sod_minor);
4174 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4187 * Unload a dlopened object and its dependencies from memory and from
4188 * our data structures. It is assumed that the DAG rooted in the
4189 * object has already been unreferenced, and that the object has a
4190 * reference count of 0.
4193 unload_object(Obj_Entry *root)
4198 assert(root->refcount == 0);
4201 * Pass over the DAG removing unreferenced objects from
4202 * appropriate lists.
4204 unlink_object(root);
4206 /* Unmap all objects that are no longer referenced. */
4207 linkp = &obj_list->next;
4208 while ((obj = *linkp) != NULL) {
4209 if (obj->refcount == 0) {
4210 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4212 dbg("unloading \"%s\"", obj->path);
4213 unload_filtees(root);
4214 munmap(obj->mapbase, obj->mapsize);
4215 linkmap_delete(obj);
4226 unlink_object(Obj_Entry *root)
4230 if (root->refcount == 0) {
4231 /* Remove the object from the RTLD_GLOBAL list. */
4232 objlist_remove(&list_global, root);
4234 /* Remove the object from all objects' DAG lists. */
4235 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4236 objlist_remove(&elm->obj->dldags, root);
4237 if (elm->obj != root)
4238 unlink_object(elm->obj);
4244 ref_dag(Obj_Entry *root)
4248 assert(root->dag_inited);
4249 STAILQ_FOREACH(elm, &root->dagmembers, link)
4250 elm->obj->refcount++;
4254 unref_dag(Obj_Entry *root)
4258 assert(root->dag_inited);
4259 STAILQ_FOREACH(elm, &root->dagmembers, link)
4260 elm->obj->refcount--;
4264 * Common code for MD __tls_get_addr().
4266 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4268 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4270 Elf_Addr *newdtv, *dtv;
4271 RtldLockState lockstate;
4275 /* Check dtv generation in case new modules have arrived */
4276 if (dtv[0] != tls_dtv_generation) {
4277 wlock_acquire(rtld_bind_lock, &lockstate);
4278 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4280 if (to_copy > tls_max_index)
4281 to_copy = tls_max_index;
4282 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4283 newdtv[0] = tls_dtv_generation;
4284 newdtv[1] = tls_max_index;
4286 lock_release(rtld_bind_lock, &lockstate);
4287 dtv = *dtvp = newdtv;
4290 /* Dynamically allocate module TLS if necessary */
4291 if (dtv[index + 1] == 0) {
4292 /* Signal safe, wlock will block out signals. */
4293 wlock_acquire(rtld_bind_lock, &lockstate);
4294 if (!dtv[index + 1])
4295 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4296 lock_release(rtld_bind_lock, &lockstate);
4298 return ((void *)(dtv[index + 1] + offset));
4302 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4307 /* Check dtv generation in case new modules have arrived */
4308 if (__predict_true(dtv[0] == tls_dtv_generation &&
4309 dtv[index + 1] != 0))
4310 return ((void *)(dtv[index + 1] + offset));
4311 return (tls_get_addr_slow(dtvp, index, offset));
4314 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__)
4317 * Allocate Static TLS using the Variant I method.
4320 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4329 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4332 assert(tcbsize >= TLS_TCB_SIZE);
4333 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4334 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4336 if (oldtcb != NULL) {
4337 memcpy(tls, oldtcb, tls_static_space);
4340 /* Adjust the DTV. */
4342 for (i = 0; i < dtv[1]; i++) {
4343 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4344 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4345 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4349 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4351 dtv[0] = tls_dtv_generation;
4352 dtv[1] = tls_max_index;
4354 for (obj = objs; obj; obj = obj->next) {
4355 if (obj->tlsoffset > 0) {
4356 addr = (Elf_Addr)tls + obj->tlsoffset;
4357 if (obj->tlsinitsize > 0)
4358 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4359 if (obj->tlssize > obj->tlsinitsize)
4360 memset((void*) (addr + obj->tlsinitsize), 0,
4361 obj->tlssize - obj->tlsinitsize);
4362 dtv[obj->tlsindex + 1] = addr;
4371 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4374 Elf_Addr tlsstart, tlsend;
4377 assert(tcbsize >= TLS_TCB_SIZE);
4379 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4380 tlsend = tlsstart + tls_static_space;
4382 dtv = *(Elf_Addr **)tlsstart;
4384 for (i = 0; i < dtvsize; i++) {
4385 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4386 free((void*)dtv[i+2]);
4395 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4398 * Allocate Static TLS using the Variant II method.
4401 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4404 size_t size, ralign;
4406 Elf_Addr *dtv, *olddtv;
4407 Elf_Addr segbase, oldsegbase, addr;
4411 if (tls_static_max_align > ralign)
4412 ralign = tls_static_max_align;
4413 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4415 assert(tcbsize >= 2*sizeof(Elf_Addr));
4416 tls = malloc_aligned(size, ralign);
4417 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4419 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4420 ((Elf_Addr*)segbase)[0] = segbase;
4421 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4423 dtv[0] = tls_dtv_generation;
4424 dtv[1] = tls_max_index;
4428 * Copy the static TLS block over whole.
4430 oldsegbase = (Elf_Addr) oldtls;
4431 memcpy((void *)(segbase - tls_static_space),
4432 (const void *)(oldsegbase - tls_static_space),
4436 * If any dynamic TLS blocks have been created tls_get_addr(),
4439 olddtv = ((Elf_Addr**)oldsegbase)[1];
4440 for (i = 0; i < olddtv[1]; i++) {
4441 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4442 dtv[i+2] = olddtv[i+2];
4448 * We assume that this block was the one we created with
4449 * allocate_initial_tls().
4451 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4453 for (obj = objs; obj; obj = obj->next) {
4454 if (obj->tlsoffset) {
4455 addr = segbase - obj->tlsoffset;
4456 memset((void*) (addr + obj->tlsinitsize),
4457 0, obj->tlssize - obj->tlsinitsize);
4459 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4460 dtv[obj->tlsindex + 1] = addr;
4465 return (void*) segbase;
4469 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4472 size_t size, ralign;
4474 Elf_Addr tlsstart, tlsend;
4477 * Figure out the size of the initial TLS block so that we can
4478 * find stuff which ___tls_get_addr() allocated dynamically.
4481 if (tls_static_max_align > ralign)
4482 ralign = tls_static_max_align;
4483 size = round(tls_static_space, ralign);
4485 dtv = ((Elf_Addr**)tls)[1];
4487 tlsend = (Elf_Addr) tls;
4488 tlsstart = tlsend - size;
4489 for (i = 0; i < dtvsize; i++) {
4490 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4491 free_aligned((void *)dtv[i + 2]);
4495 free_aligned((void *)tlsstart);
4502 * Allocate TLS block for module with given index.
4505 allocate_module_tls(int index)
4510 for (obj = obj_list; obj; obj = obj->next) {
4511 if (obj->tlsindex == index)
4515 _rtld_error("Can't find module with TLS index %d", index);
4519 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4520 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4521 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4527 allocate_tls_offset(Obj_Entry *obj)
4534 if (obj->tlssize == 0) {
4535 obj->tls_done = true;
4539 if (obj->tlsindex == 1)
4540 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4542 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4543 obj->tlssize, obj->tlsalign);
4546 * If we have already fixed the size of the static TLS block, we
4547 * must stay within that size. When allocating the static TLS, we
4548 * leave a small amount of space spare to be used for dynamically
4549 * loading modules which use static TLS.
4551 if (tls_static_space != 0) {
4552 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4554 } else if (obj->tlsalign > tls_static_max_align) {
4555 tls_static_max_align = obj->tlsalign;
4558 tls_last_offset = obj->tlsoffset = off;
4559 tls_last_size = obj->tlssize;
4560 obj->tls_done = true;
4566 free_tls_offset(Obj_Entry *obj)
4570 * If we were the last thing to allocate out of the static TLS
4571 * block, we give our space back to the 'allocator'. This is a
4572 * simplistic workaround to allow libGL.so.1 to be loaded and
4573 * unloaded multiple times.
4575 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4576 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4577 tls_last_offset -= obj->tlssize;
4583 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4586 RtldLockState lockstate;
4588 wlock_acquire(rtld_bind_lock, &lockstate);
4589 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4590 lock_release(rtld_bind_lock, &lockstate);
4595 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4597 RtldLockState lockstate;
4599 wlock_acquire(rtld_bind_lock, &lockstate);
4600 free_tls(tcb, tcbsize, tcbalign);
4601 lock_release(rtld_bind_lock, &lockstate);
4605 object_add_name(Obj_Entry *obj, const char *name)
4611 entry = malloc(sizeof(Name_Entry) + len);
4613 if (entry != NULL) {
4614 strcpy(entry->name, name);
4615 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4620 object_match_name(const Obj_Entry *obj, const char *name)
4624 STAILQ_FOREACH(entry, &obj->names, link) {
4625 if (strcmp(name, entry->name) == 0)
4632 locate_dependency(const Obj_Entry *obj, const char *name)
4634 const Objlist_Entry *entry;
4635 const Needed_Entry *needed;
4637 STAILQ_FOREACH(entry, &list_main, link) {
4638 if (object_match_name(entry->obj, name))
4642 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4643 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4644 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4646 * If there is DT_NEEDED for the name we are looking for,
4647 * we are all set. Note that object might not be found if
4648 * dependency was not loaded yet, so the function can
4649 * return NULL here. This is expected and handled
4650 * properly by the caller.
4652 return (needed->obj);
4655 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4661 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4662 const Elf_Vernaux *vna)
4664 const Elf_Verdef *vd;
4665 const char *vername;
4667 vername = refobj->strtab + vna->vna_name;
4668 vd = depobj->verdef;
4670 _rtld_error("%s: version %s required by %s not defined",
4671 depobj->path, vername, refobj->path);
4675 if (vd->vd_version != VER_DEF_CURRENT) {
4676 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4677 depobj->path, vd->vd_version);
4680 if (vna->vna_hash == vd->vd_hash) {
4681 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4682 ((char *)vd + vd->vd_aux);
4683 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4686 if (vd->vd_next == 0)
4688 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4690 if (vna->vna_flags & VER_FLG_WEAK)
4692 _rtld_error("%s: version %s required by %s not found",
4693 depobj->path, vername, refobj->path);
4698 rtld_verify_object_versions(Obj_Entry *obj)
4700 const Elf_Verneed *vn;
4701 const Elf_Verdef *vd;
4702 const Elf_Verdaux *vda;
4703 const Elf_Vernaux *vna;
4704 const Obj_Entry *depobj;
4705 int maxvernum, vernum;
4707 if (obj->ver_checked)
4709 obj->ver_checked = true;
4713 * Walk over defined and required version records and figure out
4714 * max index used by any of them. Do very basic sanity checking
4718 while (vn != NULL) {
4719 if (vn->vn_version != VER_NEED_CURRENT) {
4720 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4721 obj->path, vn->vn_version);
4724 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4726 vernum = VER_NEED_IDX(vna->vna_other);
4727 if (vernum > maxvernum)
4729 if (vna->vna_next == 0)
4731 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4733 if (vn->vn_next == 0)
4735 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4739 while (vd != NULL) {
4740 if (vd->vd_version != VER_DEF_CURRENT) {
4741 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4742 obj->path, vd->vd_version);
4745 vernum = VER_DEF_IDX(vd->vd_ndx);
4746 if (vernum > maxvernum)
4748 if (vd->vd_next == 0)
4750 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4757 * Store version information in array indexable by version index.
4758 * Verify that object version requirements are satisfied along the
4761 obj->vernum = maxvernum + 1;
4762 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4765 while (vd != NULL) {
4766 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4767 vernum = VER_DEF_IDX(vd->vd_ndx);
4768 assert(vernum <= maxvernum);
4769 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4770 obj->vertab[vernum].hash = vd->vd_hash;
4771 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4772 obj->vertab[vernum].file = NULL;
4773 obj->vertab[vernum].flags = 0;
4775 if (vd->vd_next == 0)
4777 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4781 while (vn != NULL) {
4782 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4785 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4787 if (check_object_provided_version(obj, depobj, vna))
4789 vernum = VER_NEED_IDX(vna->vna_other);
4790 assert(vernum <= maxvernum);
4791 obj->vertab[vernum].hash = vna->vna_hash;
4792 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4793 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4794 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4795 VER_INFO_HIDDEN : 0;
4796 if (vna->vna_next == 0)
4798 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4800 if (vn->vn_next == 0)
4802 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4808 rtld_verify_versions(const Objlist *objlist)
4810 Objlist_Entry *entry;
4814 STAILQ_FOREACH(entry, objlist, link) {
4816 * Skip dummy objects or objects that have their version requirements
4819 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4821 if (rtld_verify_object_versions(entry->obj) == -1) {
4823 if (ld_tracing == NULL)
4827 if (rc == 0 || ld_tracing != NULL)
4828 rc = rtld_verify_object_versions(&obj_rtld);
4833 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4838 vernum = VER_NDX(obj->versyms[symnum]);
4839 if (vernum >= obj->vernum) {
4840 _rtld_error("%s: symbol %s has wrong verneed value %d",
4841 obj->path, obj->strtab + symnum, vernum);
4842 } else if (obj->vertab[vernum].hash != 0) {
4843 return &obj->vertab[vernum];
4850 _rtld_get_stack_prot(void)
4853 return (stack_prot);
4857 _rtld_is_dlopened(void *arg)
4860 RtldLockState lockstate;
4863 rlock_acquire(rtld_bind_lock, &lockstate);
4866 obj = obj_from_addr(arg);
4868 _rtld_error("No shared object contains address");
4869 lock_release(rtld_bind_lock, &lockstate);
4872 res = obj->dlopened ? 1 : 0;
4873 lock_release(rtld_bind_lock, &lockstate);
4878 map_stacks_exec(RtldLockState *lockstate)
4880 void (*thr_map_stacks_exec)(void);
4882 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4884 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4885 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4886 if (thr_map_stacks_exec != NULL) {
4887 stack_prot |= PROT_EXEC;
4888 thr_map_stacks_exec();
4893 symlook_init(SymLook *dst, const char *name)
4896 bzero(dst, sizeof(*dst));
4898 dst->hash = elf_hash(name);
4899 dst->hash_gnu = gnu_hash(name);
4903 symlook_init_from_req(SymLook *dst, const SymLook *src)
4906 dst->name = src->name;
4907 dst->hash = src->hash;
4908 dst->hash_gnu = src->hash_gnu;
4909 dst->ventry = src->ventry;
4910 dst->flags = src->flags;
4911 dst->defobj_out = NULL;
4912 dst->sym_out = NULL;
4913 dst->lockstate = src->lockstate;
4917 * Overrides for libc_pic-provided functions.
4921 __getosreldate(void)
4931 oid[1] = KERN_OSRELDATE;
4933 len = sizeof(osrel);
4934 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4935 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4947 void (*__cleanup)(void);
4948 int __isthreaded = 0;
4949 int _thread_autoinit_dummy_decl = 1;
4952 * No unresolved symbols for rtld.
4955 __pthread_cxa_finalize(struct dl_phdr_info *a)
4960 __stack_chk_fail(void)
4963 _rtld_error("stack overflow detected; terminated");
4966 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
4972 _rtld_error("buffer overflow detected; terminated");
4977 rtld_strerror(int errnum)
4980 if (errnum < 0 || errnum >= sys_nerr)
4981 return ("Unknown error");
4982 return (sys_errlist[errnum]);