2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
37 #include <sys/param.h>
38 #include <sys/mount.h>
41 #include <sys/sysctl.h>
43 #include <sys/utsname.h>
44 #include <sys/ktrace.h>
61 #include "rtld_printf.h"
65 typedef void (*func_ptr_type)();
66 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
69 * Function declarations.
71 static const char *basename(const char *);
72 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
73 const Elf_Dyn **, const Elf_Dyn **);
74 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
76 static void digest_dynamic(Obj_Entry *, int);
77 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
78 static Obj_Entry *dlcheck(void *);
79 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
80 int lo_flags, int mode, RtldLockState *lockstate);
81 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
82 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
83 static bool donelist_check(DoneList *, const Obj_Entry *);
84 static void errmsg_restore(char *);
85 static char *errmsg_save(void);
86 static void *fill_search_info(const char *, size_t, void *);
87 static char *find_library(const char *, const Obj_Entry *, int *);
88 static const char *gethints(bool);
89 static void init_dag(Obj_Entry *);
90 static void init_pagesizes(Elf_Auxinfo **aux_info);
91 static void init_rtld(caddr_t, Elf_Auxinfo **);
92 static void initlist_add_neededs(Needed_Entry *, Objlist *);
93 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
94 static void linkmap_add(Obj_Entry *);
95 static void linkmap_delete(Obj_Entry *);
96 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
97 static void unload_filtees(Obj_Entry *);
98 static int load_needed_objects(Obj_Entry *, int);
99 static int load_preload_objects(void);
100 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
101 static void map_stacks_exec(RtldLockState *);
102 static Obj_Entry *obj_from_addr(const void *);
103 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
104 static void objlist_call_init(Objlist *, RtldLockState *);
105 static void objlist_clear(Objlist *);
106 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
107 static void objlist_init(Objlist *);
108 static void objlist_push_head(Objlist *, Obj_Entry *);
109 static void objlist_push_tail(Objlist *, Obj_Entry *);
110 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
111 static void objlist_remove(Objlist *, Obj_Entry *);
112 static int parse_libdir(const char *);
113 static void *path_enumerate(const char *, path_enum_proc, void *);
114 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
115 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
116 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
117 int flags, RtldLockState *lockstate);
118 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
120 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
121 int flags, RtldLockState *lockstate);
122 static int rtld_dirname(const char *, char *);
123 static int rtld_dirname_abs(const char *, char *);
124 static void *rtld_dlopen(const char *name, int fd, int mode);
125 static void rtld_exit(void);
126 static char *search_library_path(const char *, const char *);
127 static char *search_library_pathfds(const char *, const char *, int *);
128 static const void **get_program_var_addr(const char *, RtldLockState *);
129 static void set_program_var(const char *, const void *);
130 static int symlook_default(SymLook *, const Obj_Entry *refobj);
131 static int symlook_global(SymLook *, DoneList *);
132 static void symlook_init_from_req(SymLook *, const SymLook *);
133 static int symlook_list(SymLook *, const Objlist *, DoneList *);
134 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
135 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
136 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
137 static void trace_loaded_objects(Obj_Entry *);
138 static void unlink_object(Obj_Entry *);
139 static void unload_object(Obj_Entry *);
140 static void unref_dag(Obj_Entry *);
141 static void ref_dag(Obj_Entry *);
142 static char *origin_subst_one(Obj_Entry *, char *, const char *,
144 static char *origin_subst(Obj_Entry *, char *);
145 static bool obj_resolve_origin(Obj_Entry *obj);
146 static void preinit_main(void);
147 static int rtld_verify_versions(const Objlist *);
148 static int rtld_verify_object_versions(Obj_Entry *);
149 static void object_add_name(Obj_Entry *, const char *);
150 static int object_match_name(const Obj_Entry *, const char *);
151 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
152 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
153 struct dl_phdr_info *phdr_info);
154 static uint32_t gnu_hash(const char *);
155 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
156 const unsigned long);
158 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
159 void _r_debug_postinit(struct link_map *) __noinline __exported;
161 int __sys_openat(int, const char *, int, ...);
166 static char *error_message; /* Message for dlerror(), or NULL */
167 struct r_debug r_debug __exported; /* for GDB; */
168 static bool libmap_disable; /* Disable libmap */
169 static bool ld_loadfltr; /* Immediate filters processing */
170 static char *libmap_override; /* Maps to use in addition to libmap.conf */
171 static bool trust; /* False for setuid and setgid programs */
172 static bool dangerous_ld_env; /* True if environment variables have been
173 used to affect the libraries loaded */
174 static char *ld_bind_now; /* Environment variable for immediate binding */
175 static char *ld_debug; /* Environment variable for debugging */
176 static char *ld_library_path; /* Environment variable for search path */
177 static char *ld_library_dirs; /* Environment variable for library descriptors */
178 static char *ld_preload; /* Environment variable for libraries to
180 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
181 static char *ld_tracing; /* Called from ldd to print libs */
182 static char *ld_utrace; /* Use utrace() to log events. */
183 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
184 static Obj_Entry **obj_tail; /* Link field of last object in list */
185 static Obj_Entry *obj_main; /* The main program shared object */
186 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
187 static unsigned int obj_count; /* Number of objects in obj_list */
188 static unsigned int obj_loads; /* Number of objects in obj_list */
190 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
191 STAILQ_HEAD_INITIALIZER(list_global);
192 static Objlist list_main = /* Objects loaded at program startup */
193 STAILQ_HEAD_INITIALIZER(list_main);
194 static Objlist list_fini = /* Objects needing fini() calls */
195 STAILQ_HEAD_INITIALIZER(list_fini);
197 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
199 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
201 extern Elf_Dyn _DYNAMIC;
202 #pragma weak _DYNAMIC
203 #ifndef RTLD_IS_DYNAMIC
204 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
207 int dlclose(void *) __exported;
208 char *dlerror(void) __exported;
209 void *dlopen(const char *, int) __exported;
210 void *fdlopen(int, int) __exported;
211 void *dlsym(void *, const char *) __exported;
212 dlfunc_t dlfunc(void *, const char *) __exported;
213 void *dlvsym(void *, const char *, const char *) __exported;
214 int dladdr(const void *, Dl_info *) __exported;
215 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
216 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
217 int dlinfo(void *, int , void *) __exported;
218 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
219 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
220 int _rtld_get_stack_prot(void) __exported;
221 int _rtld_is_dlopened(void *) __exported;
222 void _rtld_error(const char *, ...) __exported;
224 int npagesizes, osreldate;
227 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
229 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
230 static int max_stack_flags;
233 * Global declarations normally provided by crt1. The dynamic linker is
234 * not built with crt1, so we have to provide them ourselves.
240 * Used to pass argc, argv to init functions.
246 * Globals to control TLS allocation.
248 size_t tls_last_offset; /* Static TLS offset of last module */
249 size_t tls_last_size; /* Static TLS size of last module */
250 size_t tls_static_space; /* Static TLS space allocated */
251 size_t tls_static_max_align;
252 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
253 int tls_max_index = 1; /* Largest module index allocated */
255 bool ld_library_path_rpath = false;
258 * Globals for path names, and such
260 char *ld_elf_hints_default = _PATH_ELF_HINTS;
261 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
262 char *ld_path_rtld = _PATH_RTLD;
263 char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
264 char *ld_env_prefix = LD_;
267 * Fill in a DoneList with an allocation large enough to hold all of
268 * the currently-loaded objects. Keep this as a macro since it calls
269 * alloca and we want that to occur within the scope of the caller.
271 #define donelist_init(dlp) \
272 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
273 assert((dlp)->objs != NULL), \
274 (dlp)->num_alloc = obj_count, \
277 #define UTRACE_DLOPEN_START 1
278 #define UTRACE_DLOPEN_STOP 2
279 #define UTRACE_DLCLOSE_START 3
280 #define UTRACE_DLCLOSE_STOP 4
281 #define UTRACE_LOAD_OBJECT 5
282 #define UTRACE_UNLOAD_OBJECT 6
283 #define UTRACE_ADD_RUNDEP 7
284 #define UTRACE_PRELOAD_FINISHED 8
285 #define UTRACE_INIT_CALL 9
286 #define UTRACE_FINI_CALL 10
287 #define UTRACE_DLSYM_START 11
288 #define UTRACE_DLSYM_STOP 12
291 char sig[4]; /* 'RTLD' */
294 void *mapbase; /* Used for 'parent' and 'init/fini' */
296 int refcnt; /* Used for 'mode' */
297 char name[MAXPATHLEN];
300 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
301 if (ld_utrace != NULL) \
302 ld_utrace_log(e, h, mb, ms, r, n); \
306 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
307 int refcnt, const char *name)
309 struct utrace_rtld ut;
317 ut.mapbase = mapbase;
318 ut.mapsize = mapsize;
320 bzero(ut.name, sizeof(ut.name));
322 strlcpy(ut.name, name, sizeof(ut.name));
323 utrace(&ut, sizeof(ut));
327 * Main entry point for dynamic linking. The first argument is the
328 * stack pointer. The stack is expected to be laid out as described
329 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
330 * Specifically, the stack pointer points to a word containing
331 * ARGC. Following that in the stack is a null-terminated sequence
332 * of pointers to argument strings. Then comes a null-terminated
333 * sequence of pointers to environment strings. Finally, there is a
334 * sequence of "auxiliary vector" entries.
336 * The second argument points to a place to store the dynamic linker's
337 * exit procedure pointer and the third to a place to store the main
340 * The return value is the main program's entry point.
343 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
345 Elf_Auxinfo *aux_info[AT_COUNT];
353 Objlist_Entry *entry;
355 Obj_Entry **preload_tail;
356 Obj_Entry *last_interposer;
358 RtldLockState lockstate;
359 char *library_path_rpath;
364 * On entry, the dynamic linker itself has not been relocated yet.
365 * Be very careful not to reference any global data until after
366 * init_rtld has returned. It is OK to reference file-scope statics
367 * and string constants, and to call static and global functions.
370 /* Find the auxiliary vector on the stack. */
373 sp += argc + 1; /* Skip over arguments and NULL terminator */
375 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
377 aux = (Elf_Auxinfo *) sp;
379 /* Digest the auxiliary vector. */
380 for (i = 0; i < AT_COUNT; i++)
382 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
383 if (auxp->a_type < AT_COUNT)
384 aux_info[auxp->a_type] = auxp;
387 /* Initialize and relocate ourselves. */
388 assert(aux_info[AT_BASE] != NULL);
389 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
391 __progname = obj_rtld.path;
392 argv0 = argv[0] != NULL ? argv[0] : "(null)";
397 if (aux_info[AT_CANARY] != NULL &&
398 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
399 i = aux_info[AT_CANARYLEN]->a_un.a_val;
400 if (i > sizeof(__stack_chk_guard))
401 i = sizeof(__stack_chk_guard);
402 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
407 len = sizeof(__stack_chk_guard);
408 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
409 len != sizeof(__stack_chk_guard)) {
410 /* If sysctl was unsuccessful, use the "terminator canary". */
411 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
412 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
413 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
414 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
418 trust = !issetugid();
420 ld_bind_now = getenv(LD_ "BIND_NOW");
422 * If the process is tainted, then we un-set the dangerous environment
423 * variables. The process will be marked as tainted until setuid(2)
424 * is called. If any child process calls setuid(2) we do not want any
425 * future processes to honor the potentially un-safe variables.
428 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
429 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBRARY_PATH_FDS") ||
430 unsetenv(LD_ "LIBMAP_DISABLE") ||
431 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
432 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
433 _rtld_error("environment corrupt; aborting");
437 ld_debug = getenv(LD_ "DEBUG");
438 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
439 libmap_override = getenv(LD_ "LIBMAP");
440 ld_library_path = getenv(LD_ "LIBRARY_PATH");
441 ld_library_dirs = getenv(LD_ "LIBRARY_PATH_FDS");
442 ld_preload = getenv(LD_ "PRELOAD");
443 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
444 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
445 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
446 if (library_path_rpath != NULL) {
447 if (library_path_rpath[0] == 'y' ||
448 library_path_rpath[0] == 'Y' ||
449 library_path_rpath[0] == '1')
450 ld_library_path_rpath = true;
452 ld_library_path_rpath = false;
454 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
455 (ld_library_path != NULL) || (ld_preload != NULL) ||
456 (ld_elf_hints_path != NULL) || ld_loadfltr;
457 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
458 ld_utrace = getenv(LD_ "UTRACE");
460 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
461 ld_elf_hints_path = ld_elf_hints_default;
463 if (ld_debug != NULL && *ld_debug != '\0')
465 dbg("%s is initialized, base address = %p", __progname,
466 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
467 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
468 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
470 dbg("initializing thread locks");
474 * Load the main program, or process its program header if it is
477 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
478 int fd = aux_info[AT_EXECFD]->a_un.a_val;
479 dbg("loading main program");
480 obj_main = map_object(fd, argv0, NULL);
482 if (obj_main == NULL)
484 max_stack_flags = obj->stack_flags;
485 } else { /* Main program already loaded. */
486 const Elf_Phdr *phdr;
490 dbg("processing main program's program header");
491 assert(aux_info[AT_PHDR] != NULL);
492 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
493 assert(aux_info[AT_PHNUM] != NULL);
494 phnum = aux_info[AT_PHNUM]->a_un.a_val;
495 assert(aux_info[AT_PHENT] != NULL);
496 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
497 assert(aux_info[AT_ENTRY] != NULL);
498 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
499 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
503 if (aux_info[AT_EXECPATH] != 0) {
505 char buf[MAXPATHLEN];
507 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
508 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
509 if (kexecpath[0] == '/')
510 obj_main->path = kexecpath;
511 else if (getcwd(buf, sizeof(buf)) == NULL ||
512 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
513 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
514 obj_main->path = xstrdup(argv0);
516 obj_main->path = xstrdup(buf);
518 dbg("No AT_EXECPATH");
519 obj_main->path = xstrdup(argv0);
521 dbg("obj_main path %s", obj_main->path);
522 obj_main->mainprog = true;
524 if (aux_info[AT_STACKPROT] != NULL &&
525 aux_info[AT_STACKPROT]->a_un.a_val != 0)
526 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
530 * Get the actual dynamic linker pathname from the executable if
531 * possible. (It should always be possible.) That ensures that
532 * gdb will find the right dynamic linker even if a non-standard
535 if (obj_main->interp != NULL &&
536 strcmp(obj_main->interp, obj_rtld.path) != 0) {
538 obj_rtld.path = xstrdup(obj_main->interp);
539 __progname = obj_rtld.path;
543 digest_dynamic(obj_main, 0);
544 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
545 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
546 obj_main->dynsymcount);
548 linkmap_add(obj_main);
549 linkmap_add(&obj_rtld);
551 /* Link the main program into the list of objects. */
552 *obj_tail = obj_main;
553 obj_tail = &obj_main->next;
557 /* Initialize a fake symbol for resolving undefined weak references. */
558 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
559 sym_zero.st_shndx = SHN_UNDEF;
560 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
563 libmap_disable = (bool)lm_init(libmap_override);
565 dbg("loading LD_PRELOAD libraries");
566 if (load_preload_objects() == -1)
568 preload_tail = obj_tail;
570 dbg("loading needed objects");
571 if (load_needed_objects(obj_main, 0) == -1)
574 /* Make a list of all objects loaded at startup. */
575 last_interposer = obj_main;
576 for (obj = obj_list; obj != NULL; obj = obj->next) {
577 if (obj->z_interpose && obj != obj_main) {
578 objlist_put_after(&list_main, last_interposer, obj);
579 last_interposer = obj;
581 objlist_push_tail(&list_main, obj);
586 dbg("checking for required versions");
587 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
590 if (ld_tracing) { /* We're done */
591 trace_loaded_objects(obj_main);
595 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
596 dump_relocations(obj_main);
601 * Processing tls relocations requires having the tls offsets
602 * initialized. Prepare offsets before starting initial
603 * relocation processing.
605 dbg("initializing initial thread local storage offsets");
606 STAILQ_FOREACH(entry, &list_main, link) {
608 * Allocate all the initial objects out of the static TLS
609 * block even if they didn't ask for it.
611 allocate_tls_offset(entry->obj);
614 if (relocate_objects(obj_main,
615 ld_bind_now != NULL && *ld_bind_now != '\0',
616 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
619 dbg("doing copy relocations");
620 if (do_copy_relocations(obj_main) == -1)
623 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
624 dump_relocations(obj_main);
629 * Setup TLS for main thread. This must be done after the
630 * relocations are processed, since tls initialization section
631 * might be the subject for relocations.
633 dbg("initializing initial thread local storage");
634 allocate_initial_tls(obj_list);
636 dbg("initializing key program variables");
637 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
638 set_program_var("environ", env);
639 set_program_var("__elf_aux_vector", aux);
641 /* Make a list of init functions to call. */
642 objlist_init(&initlist);
643 initlist_add_objects(obj_list, preload_tail, &initlist);
645 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
647 map_stacks_exec(NULL);
649 dbg("resolving ifuncs");
650 if (resolve_objects_ifunc(obj_main,
651 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
655 if (!obj_main->crt_no_init) {
657 * Make sure we don't call the main program's init and fini
658 * functions for binaries linked with old crt1 which calls
661 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
662 obj_main->preinit_array = obj_main->init_array =
663 obj_main->fini_array = (Elf_Addr)NULL;
666 wlock_acquire(rtld_bind_lock, &lockstate);
667 if (obj_main->crt_no_init)
669 objlist_call_init(&initlist, &lockstate);
670 _r_debug_postinit(&obj_main->linkmap);
671 objlist_clear(&initlist);
672 dbg("loading filtees");
673 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
674 if (ld_loadfltr || obj->z_loadfltr)
675 load_filtees(obj, 0, &lockstate);
677 lock_release(rtld_bind_lock, &lockstate);
679 dbg("transferring control to program entry point = %p", obj_main->entry);
681 /* Return the exit procedure and the program entry point. */
682 *exit_proc = rtld_exit;
684 return (func_ptr_type) obj_main->entry;
688 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
693 ptr = (void *)make_function_pointer(def, obj);
694 target = ((Elf_Addr (*)(void))ptr)();
695 return ((void *)target);
699 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
703 const Obj_Entry *defobj;
706 RtldLockState lockstate;
708 rlock_acquire(rtld_bind_lock, &lockstate);
709 if (sigsetjmp(lockstate.env, 0) != 0)
710 lock_upgrade(rtld_bind_lock, &lockstate);
712 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
714 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
716 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
717 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
721 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
722 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
724 target = (Elf_Addr)(defobj->relocbase + def->st_value);
726 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
727 defobj->strtab + def->st_name, basename(obj->path),
728 (void *)target, basename(defobj->path));
731 * Write the new contents for the jmpslot. Note that depending on
732 * architecture, the value which we need to return back to the
733 * lazy binding trampoline may or may not be the target
734 * address. The value returned from reloc_jmpslot() is the value
735 * that the trampoline needs.
737 target = reloc_jmpslot(where, target, defobj, obj, rel);
738 lock_release(rtld_bind_lock, &lockstate);
743 * Error reporting function. Use it like printf. If formats the message
744 * into a buffer, and sets things up so that the next call to dlerror()
745 * will return the message.
748 _rtld_error(const char *fmt, ...)
750 static char buf[512];
754 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
760 * Return a dynamically-allocated copy of the current error message, if any.
765 return error_message == NULL ? NULL : xstrdup(error_message);
769 * Restore the current error message from a copy which was previously saved
770 * by errmsg_save(). The copy is freed.
773 errmsg_restore(char *saved_msg)
775 if (saved_msg == NULL)
776 error_message = NULL;
778 _rtld_error("%s", saved_msg);
784 basename(const char *name)
786 const char *p = strrchr(name, '/');
787 return p != NULL ? p + 1 : name;
790 static struct utsname uts;
793 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
794 const char *subst, bool may_free)
796 char *p, *p1, *res, *resp;
797 int subst_len, kw_len, subst_count, old_len, new_len;
802 * First, count the number of the keyword occurences, to
803 * preallocate the final string.
805 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
812 * If the keyword is not found, just return.
814 * Return non-substituted string if resolution failed. We
815 * cannot do anything more reasonable, the failure mode of the
816 * caller is unresolved library anyway.
818 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
819 return (may_free ? real : xstrdup(real));
821 subst = obj->origin_path;
824 * There is indeed something to substitute. Calculate the
825 * length of the resulting string, and allocate it.
827 subst_len = strlen(subst);
828 old_len = strlen(real);
829 new_len = old_len + (subst_len - kw_len) * subst_count;
830 res = xmalloc(new_len + 1);
833 * Now, execute the substitution loop.
835 for (p = real, resp = res, *resp = '\0';;) {
838 /* Copy the prefix before keyword. */
839 memcpy(resp, p, p1 - p);
841 /* Keyword replacement. */
842 memcpy(resp, subst, subst_len);
850 /* Copy to the end of string and finish. */
858 origin_subst(Obj_Entry *obj, char *real)
860 char *res1, *res2, *res3, *res4;
862 if (obj == NULL || !trust)
863 return (xstrdup(real));
864 if (uts.sysname[0] == '\0') {
865 if (uname(&uts) != 0) {
866 _rtld_error("utsname failed: %d", errno);
870 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
871 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
872 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
873 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
880 const char *msg = dlerror();
884 rtld_fdputstr(STDERR_FILENO, msg);
885 rtld_fdputchar(STDERR_FILENO, '\n');
890 * Process a shared object's DYNAMIC section, and save the important
891 * information in its Obj_Entry structure.
894 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
895 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
898 Needed_Entry **needed_tail = &obj->needed;
899 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
900 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
901 const Elf_Hashelt *hashtab;
902 const Elf32_Word *hashval;
903 Elf32_Word bkt, nmaskwords;
905 int plttype = DT_REL;
911 obj->bind_now = false;
912 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
913 switch (dynp->d_tag) {
916 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
920 obj->relsize = dynp->d_un.d_val;
924 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
928 obj->pltrel = (const Elf_Rel *)
929 (obj->relocbase + dynp->d_un.d_ptr);
933 obj->pltrelsize = dynp->d_un.d_val;
937 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
941 obj->relasize = dynp->d_un.d_val;
945 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
949 plttype = dynp->d_un.d_val;
950 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
954 obj->symtab = (const Elf_Sym *)
955 (obj->relocbase + dynp->d_un.d_ptr);
959 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
963 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
967 obj->strsize = dynp->d_un.d_val;
971 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
976 obj->verneednum = dynp->d_un.d_val;
980 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
985 obj->verdefnum = dynp->d_un.d_val;
989 obj->versyms = (const Elf_Versym *)(obj->relocbase +
995 hashtab = (const Elf_Hashelt *)(obj->relocbase +
997 obj->nbuckets = hashtab[0];
998 obj->nchains = hashtab[1];
999 obj->buckets = hashtab + 2;
1000 obj->chains = obj->buckets + obj->nbuckets;
1001 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1002 obj->buckets != NULL;
1008 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1010 obj->nbuckets_gnu = hashtab[0];
1011 obj->symndx_gnu = hashtab[1];
1012 nmaskwords = hashtab[2];
1013 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1014 obj->maskwords_bm_gnu = nmaskwords - 1;
1015 obj->shift2_gnu = hashtab[3];
1016 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1017 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1018 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1020 /* Number of bitmask words is required to be power of 2 */
1021 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1022 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1028 Needed_Entry *nep = NEW(Needed_Entry);
1029 nep->name = dynp->d_un.d_val;
1034 needed_tail = &nep->next;
1040 Needed_Entry *nep = NEW(Needed_Entry);
1041 nep->name = dynp->d_un.d_val;
1045 *needed_filtees_tail = nep;
1046 needed_filtees_tail = &nep->next;
1052 Needed_Entry *nep = NEW(Needed_Entry);
1053 nep->name = dynp->d_un.d_val;
1057 *needed_aux_filtees_tail = nep;
1058 needed_aux_filtees_tail = &nep->next;
1063 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1067 obj->textrel = true;
1071 obj->symbolic = true;
1076 * We have to wait until later to process this, because we
1077 * might not have gotten the address of the string table yet.
1087 *dyn_runpath = dynp;
1091 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1094 case DT_PREINIT_ARRAY:
1095 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1098 case DT_PREINIT_ARRAYSZ:
1099 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1103 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1106 case DT_INIT_ARRAYSZ:
1107 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1111 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1115 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1118 case DT_FINI_ARRAYSZ:
1119 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1123 * Don't process DT_DEBUG on MIPS as the dynamic section
1124 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1130 dbg("Filling in DT_DEBUG entry");
1131 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1136 if (dynp->d_un.d_val & DF_ORIGIN)
1137 obj->z_origin = true;
1138 if (dynp->d_un.d_val & DF_SYMBOLIC)
1139 obj->symbolic = true;
1140 if (dynp->d_un.d_val & DF_TEXTREL)
1141 obj->textrel = true;
1142 if (dynp->d_un.d_val & DF_BIND_NOW)
1143 obj->bind_now = true;
1144 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1148 case DT_MIPS_LOCAL_GOTNO:
1149 obj->local_gotno = dynp->d_un.d_val;
1152 case DT_MIPS_SYMTABNO:
1153 obj->symtabno = dynp->d_un.d_val;
1156 case DT_MIPS_GOTSYM:
1157 obj->gotsym = dynp->d_un.d_val;
1160 case DT_MIPS_RLD_MAP:
1161 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1165 #ifdef __powerpc64__
1166 case DT_PPC64_GLINK:
1167 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1172 if (dynp->d_un.d_val & DF_1_NOOPEN)
1173 obj->z_noopen = true;
1174 if (dynp->d_un.d_val & DF_1_ORIGIN)
1175 obj->z_origin = true;
1176 if (dynp->d_un.d_val & DF_1_GLOBAL)
1177 obj->z_global = true;
1178 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1179 obj->bind_now = true;
1180 if (dynp->d_un.d_val & DF_1_NODELETE)
1181 obj->z_nodelete = true;
1182 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1183 obj->z_loadfltr = true;
1184 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1185 obj->z_interpose = true;
1186 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1187 obj->z_nodeflib = true;
1192 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1199 obj->traced = false;
1201 if (plttype == DT_RELA) {
1202 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1204 obj->pltrelasize = obj->pltrelsize;
1205 obj->pltrelsize = 0;
1208 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1209 if (obj->valid_hash_sysv)
1210 obj->dynsymcount = obj->nchains;
1211 else if (obj->valid_hash_gnu) {
1212 obj->dynsymcount = 0;
1213 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1214 if (obj->buckets_gnu[bkt] == 0)
1216 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1219 while ((*hashval++ & 1u) == 0);
1221 obj->dynsymcount += obj->symndx_gnu;
1226 obj_resolve_origin(Obj_Entry *obj)
1229 if (obj->origin_path != NULL)
1231 obj->origin_path = xmalloc(PATH_MAX);
1232 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1236 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1237 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1240 if (obj->z_origin && !obj_resolve_origin(obj))
1243 if (dyn_runpath != NULL) {
1244 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1245 obj->runpath = origin_subst(obj, obj->runpath);
1246 } else if (dyn_rpath != NULL) {
1247 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1248 obj->rpath = origin_subst(obj, obj->rpath);
1250 if (dyn_soname != NULL)
1251 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1255 digest_dynamic(Obj_Entry *obj, int early)
1257 const Elf_Dyn *dyn_rpath;
1258 const Elf_Dyn *dyn_soname;
1259 const Elf_Dyn *dyn_runpath;
1261 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1262 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1266 * Process a shared object's program header. This is used only for the
1267 * main program, when the kernel has already loaded the main program
1268 * into memory before calling the dynamic linker. It creates and
1269 * returns an Obj_Entry structure.
1272 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1275 const Elf_Phdr *phlimit = phdr + phnum;
1277 Elf_Addr note_start, note_end;
1281 for (ph = phdr; ph < phlimit; ph++) {
1282 if (ph->p_type != PT_PHDR)
1286 obj->phsize = ph->p_memsz;
1287 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1291 obj->stack_flags = PF_X | PF_R | PF_W;
1293 for (ph = phdr; ph < phlimit; ph++) {
1294 switch (ph->p_type) {
1297 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1301 if (nsegs == 0) { /* First load segment */
1302 obj->vaddrbase = trunc_page(ph->p_vaddr);
1303 obj->mapbase = obj->vaddrbase + obj->relocbase;
1304 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1306 } else { /* Last load segment */
1307 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1314 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1319 obj->tlssize = ph->p_memsz;
1320 obj->tlsalign = ph->p_align;
1321 obj->tlsinitsize = ph->p_filesz;
1322 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1326 obj->stack_flags = ph->p_flags;
1330 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1331 obj->relro_size = round_page(ph->p_memsz);
1335 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1336 note_end = note_start + ph->p_filesz;
1337 digest_notes(obj, note_start, note_end);
1342 _rtld_error("%s: too few PT_LOAD segments", path);
1351 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1353 const Elf_Note *note;
1354 const char *note_name;
1357 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1358 note = (const Elf_Note *)((const char *)(note + 1) +
1359 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1360 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1361 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1362 note->n_descsz != sizeof(int32_t))
1364 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1365 note->n_type != NT_FREEBSD_NOINIT_TAG)
1367 note_name = (const char *)(note + 1);
1368 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1369 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1371 switch (note->n_type) {
1372 case NT_FREEBSD_ABI_TAG:
1373 /* FreeBSD osrel note */
1374 p = (uintptr_t)(note + 1);
1375 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1376 obj->osrel = *(const int32_t *)(p);
1377 dbg("note osrel %d", obj->osrel);
1379 case NT_FREEBSD_NOINIT_TAG:
1380 /* FreeBSD 'crt does not call init' note */
1381 obj->crt_no_init = true;
1382 dbg("note crt_no_init");
1389 dlcheck(void *handle)
1393 for (obj = obj_list; obj != NULL; obj = obj->next)
1394 if (obj == (Obj_Entry *) handle)
1397 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1398 _rtld_error("Invalid shared object handle %p", handle);
1405 * If the given object is already in the donelist, return true. Otherwise
1406 * add the object to the list and return false.
1409 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1413 for (i = 0; i < dlp->num_used; i++)
1414 if (dlp->objs[i] == obj)
1417 * Our donelist allocation should always be sufficient. But if
1418 * our threads locking isn't working properly, more shared objects
1419 * could have been loaded since we allocated the list. That should
1420 * never happen, but we'll handle it properly just in case it does.
1422 if (dlp->num_used < dlp->num_alloc)
1423 dlp->objs[dlp->num_used++] = obj;
1428 * Hash function for symbol table lookup. Don't even think about changing
1429 * this. It is specified by the System V ABI.
1432 elf_hash(const char *name)
1434 const unsigned char *p = (const unsigned char *) name;
1435 unsigned long h = 0;
1438 while (*p != '\0') {
1439 h = (h << 4) + *p++;
1440 if ((g = h & 0xf0000000) != 0)
1448 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1449 * unsigned in case it's implemented with a wider type.
1452 gnu_hash(const char *s)
1458 for (c = *s; c != '\0'; c = *++s)
1460 return (h & 0xffffffff);
1465 * Find the library with the given name, and return its full pathname.
1466 * The returned string is dynamically allocated. Generates an error
1467 * message and returns NULL if the library cannot be found.
1469 * If the second argument is non-NULL, then it refers to an already-
1470 * loaded shared object, whose library search path will be searched.
1472 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1473 * descriptor (which is close-on-exec) will be passed out via the third
1476 * The search order is:
1477 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1478 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1480 * DT_RUNPATH in the referencing file
1481 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1483 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1485 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1488 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1492 bool nodeflib, objgiven;
1494 objgiven = refobj != NULL;
1495 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1496 if (xname[0] != '/' && !trust) {
1497 _rtld_error("Absolute pathname required for shared object \"%s\"",
1501 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1502 __DECONST(char *, xname)));
1505 if (libmap_disable || !objgiven ||
1506 (name = lm_find(refobj->path, xname)) == NULL)
1507 name = (char *)xname;
1509 dbg(" Searching for \"%s\"", name);
1512 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1513 * back to pre-conforming behaviour if user requested so with
1514 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1517 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1518 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1520 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1521 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1522 (pathname = search_library_path(name, gethints(false))) != NULL ||
1523 (pathname = search_library_path(name, ld_standard_library_path)) != NULL)
1526 nodeflib = objgiven ? refobj->z_nodeflib : false;
1528 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1529 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1530 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1531 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1533 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1534 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1535 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1536 (objgiven && !nodeflib &&
1537 (pathname = search_library_path(name, ld_standard_library_path)) != NULL))
1541 if (objgiven && refobj->path != NULL) {
1542 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1543 name, basename(refobj->path));
1545 _rtld_error("Shared object \"%s\" not found", name);
1551 * Given a symbol number in a referencing object, find the corresponding
1552 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1553 * no definition was found. Returns a pointer to the Obj_Entry of the
1554 * defining object via the reference parameter DEFOBJ_OUT.
1557 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1558 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1559 RtldLockState *lockstate)
1563 const Obj_Entry *defobj;
1569 * If we have already found this symbol, get the information from
1572 if (symnum >= refobj->dynsymcount)
1573 return NULL; /* Bad object */
1574 if (cache != NULL && cache[symnum].sym != NULL) {
1575 *defobj_out = cache[symnum].obj;
1576 return cache[symnum].sym;
1579 ref = refobj->symtab + symnum;
1580 name = refobj->strtab + ref->st_name;
1585 * We don't have to do a full scale lookup if the symbol is local.
1586 * We know it will bind to the instance in this load module; to
1587 * which we already have a pointer (ie ref). By not doing a lookup,
1588 * we not only improve performance, but it also avoids unresolvable
1589 * symbols when local symbols are not in the hash table. This has
1590 * been seen with the ia64 toolchain.
1592 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1593 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1594 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1597 symlook_init(&req, name);
1599 req.ventry = fetch_ventry(refobj, symnum);
1600 req.lockstate = lockstate;
1601 res = symlook_default(&req, refobj);
1604 defobj = req.defobj_out;
1612 * If we found no definition and the reference is weak, treat the
1613 * symbol as having the value zero.
1615 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1621 *defobj_out = defobj;
1622 /* Record the information in the cache to avoid subsequent lookups. */
1623 if (cache != NULL) {
1624 cache[symnum].sym = def;
1625 cache[symnum].obj = defobj;
1628 if (refobj != &obj_rtld)
1629 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1635 * Return the search path from the ldconfig hints file, reading it if
1636 * necessary. If nostdlib is true, then the default search paths are
1637 * not added to result.
1639 * Returns NULL if there are problems with the hints file,
1640 * or if the search path there is empty.
1643 gethints(bool nostdlib)
1645 static char *hints, *filtered_path;
1646 struct elfhints_hdr hdr;
1647 struct fill_search_info_args sargs, hargs;
1648 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1649 struct dl_serpath *SLPpath, *hintpath;
1651 unsigned int SLPndx, hintndx, fndx, fcount;
1656 /* First call, read the hints file */
1657 if (hints == NULL) {
1658 /* Keep from trying again in case the hints file is bad. */
1661 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1663 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1664 hdr.magic != ELFHINTS_MAGIC ||
1669 p = xmalloc(hdr.dirlistlen + 1);
1670 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1671 read(fd, p, hdr.dirlistlen + 1) !=
1672 (ssize_t)hdr.dirlistlen + 1) {
1682 * If caller agreed to receive list which includes the default
1683 * paths, we are done. Otherwise, if we still did not
1684 * calculated filtered result, do it now.
1687 return (hints[0] != '\0' ? hints : NULL);
1688 if (filtered_path != NULL)
1692 * Obtain the list of all configured search paths, and the
1693 * list of the default paths.
1695 * First estimate the size of the results.
1697 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1699 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1702 sargs.request = RTLD_DI_SERINFOSIZE;
1703 sargs.serinfo = &smeta;
1704 hargs.request = RTLD_DI_SERINFOSIZE;
1705 hargs.serinfo = &hmeta;
1707 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1708 path_enumerate(p, fill_search_info, &hargs);
1710 SLPinfo = xmalloc(smeta.dls_size);
1711 hintinfo = xmalloc(hmeta.dls_size);
1714 * Next fetch both sets of paths.
1716 sargs.request = RTLD_DI_SERINFO;
1717 sargs.serinfo = SLPinfo;
1718 sargs.serpath = &SLPinfo->dls_serpath[0];
1719 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1721 hargs.request = RTLD_DI_SERINFO;
1722 hargs.serinfo = hintinfo;
1723 hargs.serpath = &hintinfo->dls_serpath[0];
1724 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1726 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1727 path_enumerate(p, fill_search_info, &hargs);
1730 * Now calculate the difference between two sets, by excluding
1731 * standard paths from the full set.
1735 filtered_path = xmalloc(hdr.dirlistlen + 1);
1736 hintpath = &hintinfo->dls_serpath[0];
1737 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1739 SLPpath = &SLPinfo->dls_serpath[0];
1741 * Check each standard path against current.
1743 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1744 /* matched, skip the path */
1745 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1753 * Not matched against any standard path, add the path
1754 * to result. Separate consequtive paths with ':'.
1757 filtered_path[fndx] = ':';
1761 flen = strlen(hintpath->dls_name);
1762 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1765 filtered_path[fndx] = '\0';
1771 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1775 init_dag(Obj_Entry *root)
1777 const Needed_Entry *needed;
1778 const Objlist_Entry *elm;
1781 if (root->dag_inited)
1783 donelist_init(&donelist);
1785 /* Root object belongs to own DAG. */
1786 objlist_push_tail(&root->dldags, root);
1787 objlist_push_tail(&root->dagmembers, root);
1788 donelist_check(&donelist, root);
1791 * Add dependencies of root object to DAG in breadth order
1792 * by exploiting the fact that each new object get added
1793 * to the tail of the dagmembers list.
1795 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1796 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1797 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1799 objlist_push_tail(&needed->obj->dldags, root);
1800 objlist_push_tail(&root->dagmembers, needed->obj);
1803 root->dag_inited = true;
1807 process_z(Obj_Entry *root)
1809 const Objlist_Entry *elm;
1813 * Walk over object DAG and process every dependent object
1814 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
1815 * to grow their own DAG.
1817 * For DF_1_GLOBAL, DAG is required for symbol lookups in
1818 * symlook_global() to work.
1820 * For DF_1_NODELETE, the DAG should have its reference upped.
1822 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1826 if (obj->z_nodelete && !obj->ref_nodel) {
1827 dbg("obj %s -z nodelete", obj->path);
1830 obj->ref_nodel = true;
1832 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
1833 dbg("obj %s -z global", obj->path);
1834 objlist_push_tail(&list_global, obj);
1840 * Initialize the dynamic linker. The argument is the address at which
1841 * the dynamic linker has been mapped into memory. The primary task of
1842 * this function is to relocate the dynamic linker.
1845 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1847 Obj_Entry objtmp; /* Temporary rtld object */
1848 const Elf_Dyn *dyn_rpath;
1849 const Elf_Dyn *dyn_soname;
1850 const Elf_Dyn *dyn_runpath;
1852 #ifdef RTLD_INIT_PAGESIZES_EARLY
1853 /* The page size is required by the dynamic memory allocator. */
1854 init_pagesizes(aux_info);
1858 * Conjure up an Obj_Entry structure for the dynamic linker.
1860 * The "path" member can't be initialized yet because string constants
1861 * cannot yet be accessed. Below we will set it correctly.
1863 memset(&objtmp, 0, sizeof(objtmp));
1866 objtmp.mapbase = mapbase;
1868 objtmp.relocbase = mapbase;
1870 if (RTLD_IS_DYNAMIC()) {
1871 objtmp.dynamic = rtld_dynamic(&objtmp);
1872 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1873 assert(objtmp.needed == NULL);
1874 #if !defined(__mips__)
1875 /* MIPS has a bogus DT_TEXTREL. */
1876 assert(!objtmp.textrel);
1880 * Temporarily put the dynamic linker entry into the object list, so
1881 * that symbols can be found.
1884 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1887 /* Initialize the object list. */
1888 obj_tail = &obj_list;
1890 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1891 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1893 #ifndef RTLD_INIT_PAGESIZES_EARLY
1894 /* The page size is required by the dynamic memory allocator. */
1895 init_pagesizes(aux_info);
1898 if (aux_info[AT_OSRELDATE] != NULL)
1899 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1901 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1903 /* Replace the path with a dynamically allocated copy. */
1904 obj_rtld.path = xstrdup(ld_path_rtld);
1906 r_debug.r_brk = r_debug_state;
1907 r_debug.r_state = RT_CONSISTENT;
1911 * Retrieve the array of supported page sizes. The kernel provides the page
1912 * sizes in increasing order.
1915 init_pagesizes(Elf_Auxinfo **aux_info)
1917 static size_t psa[MAXPAGESIZES];
1921 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1923 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1924 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1927 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1930 /* As a fallback, retrieve the base page size. */
1931 size = sizeof(psa[0]);
1932 if (aux_info[AT_PAGESZ] != NULL) {
1933 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1937 mib[1] = HW_PAGESIZE;
1941 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1942 _rtld_error("sysctl for hw.pagesize(s) failed");
1948 npagesizes = size / sizeof(pagesizes[0]);
1949 /* Discard any invalid entries at the end of the array. */
1950 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1955 * Add the init functions from a needed object list (and its recursive
1956 * needed objects) to "list". This is not used directly; it is a helper
1957 * function for initlist_add_objects(). The write lock must be held
1958 * when this function is called.
1961 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1963 /* Recursively process the successor needed objects. */
1964 if (needed->next != NULL)
1965 initlist_add_neededs(needed->next, list);
1967 /* Process the current needed object. */
1968 if (needed->obj != NULL)
1969 initlist_add_objects(needed->obj, &needed->obj->next, list);
1973 * Scan all of the DAGs rooted in the range of objects from "obj" to
1974 * "tail" and add their init functions to "list". This recurses over
1975 * the DAGs and ensure the proper init ordering such that each object's
1976 * needed libraries are initialized before the object itself. At the
1977 * same time, this function adds the objects to the global finalization
1978 * list "list_fini" in the opposite order. The write lock must be
1979 * held when this function is called.
1982 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1985 if (obj->init_scanned || obj->init_done)
1987 obj->init_scanned = true;
1989 /* Recursively process the successor objects. */
1990 if (&obj->next != tail)
1991 initlist_add_objects(obj->next, tail, list);
1993 /* Recursively process the needed objects. */
1994 if (obj->needed != NULL)
1995 initlist_add_neededs(obj->needed, list);
1996 if (obj->needed_filtees != NULL)
1997 initlist_add_neededs(obj->needed_filtees, list);
1998 if (obj->needed_aux_filtees != NULL)
1999 initlist_add_neededs(obj->needed_aux_filtees, list);
2001 /* Add the object to the init list. */
2002 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
2003 obj->init_array != (Elf_Addr)NULL)
2004 objlist_push_tail(list, obj);
2006 /* Add the object to the global fini list in the reverse order. */
2007 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2008 && !obj->on_fini_list) {
2009 objlist_push_head(&list_fini, obj);
2010 obj->on_fini_list = true;
2015 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2019 free_needed_filtees(Needed_Entry *n)
2021 Needed_Entry *needed, *needed1;
2023 for (needed = n; needed != NULL; needed = needed->next) {
2024 if (needed->obj != NULL) {
2025 dlclose(needed->obj);
2029 for (needed = n; needed != NULL; needed = needed1) {
2030 needed1 = needed->next;
2036 unload_filtees(Obj_Entry *obj)
2039 free_needed_filtees(obj->needed_filtees);
2040 obj->needed_filtees = NULL;
2041 free_needed_filtees(obj->needed_aux_filtees);
2042 obj->needed_aux_filtees = NULL;
2043 obj->filtees_loaded = false;
2047 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2048 RtldLockState *lockstate)
2051 for (; needed != NULL; needed = needed->next) {
2052 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2053 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2054 RTLD_LOCAL, lockstate);
2059 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2062 lock_restart_for_upgrade(lockstate);
2063 if (!obj->filtees_loaded) {
2064 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2065 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2066 obj->filtees_loaded = true;
2071 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2075 for (; needed != NULL; needed = needed->next) {
2076 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2077 flags & ~RTLD_LO_NOLOAD);
2078 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2085 * Given a shared object, traverse its list of needed objects, and load
2086 * each of them. Returns 0 on success. Generates an error message and
2087 * returns -1 on failure.
2090 load_needed_objects(Obj_Entry *first, int flags)
2094 for (obj = first; obj != NULL; obj = obj->next) {
2095 if (process_needed(obj, obj->needed, flags) == -1)
2102 load_preload_objects(void)
2104 char *p = ld_preload;
2106 static const char delim[] = " \t:;";
2111 p += strspn(p, delim);
2112 while (*p != '\0') {
2113 size_t len = strcspn(p, delim);
2118 obj = load_object(p, -1, NULL, 0);
2120 return -1; /* XXX - cleanup */
2121 obj->z_interpose = true;
2124 p += strspn(p, delim);
2126 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2131 printable_path(const char *path)
2134 return (path == NULL ? "<unknown>" : path);
2138 * Load a shared object into memory, if it is not already loaded. The
2139 * object may be specified by name or by user-supplied file descriptor
2140 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2143 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2147 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2156 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2157 if (object_match_name(obj, name))
2161 path = find_library(name, refobj, &fd);
2169 * search_library_pathfds() opens a fresh file descriptor for the
2170 * library, so there is no need to dup().
2172 } else if (fd_u == -1) {
2174 * If we didn't find a match by pathname, or the name is not
2175 * supplied, open the file and check again by device and inode.
2176 * This avoids false mismatches caused by multiple links or ".."
2179 * To avoid a race, we open the file and use fstat() rather than
2182 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2183 _rtld_error("Cannot open \"%s\"", path);
2188 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2190 _rtld_error("Cannot dup fd");
2195 if (fstat(fd, &sb) == -1) {
2196 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2201 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2202 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2204 if (obj != NULL && name != NULL) {
2205 object_add_name(obj, name);
2210 if (flags & RTLD_LO_NOLOAD) {
2216 /* First use of this object, so we must map it in */
2217 obj = do_load_object(fd, name, path, &sb, flags);
2226 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2233 * but first, make sure that environment variables haven't been
2234 * used to circumvent the noexec flag on a filesystem.
2236 if (dangerous_ld_env) {
2237 if (fstatfs(fd, &fs) != 0) {
2238 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2241 if (fs.f_flags & MNT_NOEXEC) {
2242 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2246 dbg("loading \"%s\"", printable_path(path));
2247 obj = map_object(fd, printable_path(path), sbp);
2252 * If DT_SONAME is present in the object, digest_dynamic2 already
2253 * added it to the object names.
2256 object_add_name(obj, name);
2258 digest_dynamic(obj, 0);
2259 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2260 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2261 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2263 dbg("refusing to load non-loadable \"%s\"", obj->path);
2264 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2265 munmap(obj->mapbase, obj->mapsize);
2270 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2272 obj_tail = &obj->next;
2275 linkmap_add(obj); /* for GDB & dlinfo() */
2276 max_stack_flags |= obj->stack_flags;
2278 dbg(" %p .. %p: %s", obj->mapbase,
2279 obj->mapbase + obj->mapsize - 1, obj->path);
2281 dbg(" WARNING: %s has impure text", obj->path);
2282 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2289 obj_from_addr(const void *addr)
2293 for (obj = obj_list; obj != NULL; obj = obj->next) {
2294 if (addr < (void *) obj->mapbase)
2296 if (addr < (void *) (obj->mapbase + obj->mapsize))
2305 Elf_Addr *preinit_addr;
2308 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2309 if (preinit_addr == NULL)
2312 for (index = 0; index < obj_main->preinit_array_num; index++) {
2313 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2314 dbg("calling preinit function for %s at %p", obj_main->path,
2315 (void *)preinit_addr[index]);
2316 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2317 0, 0, obj_main->path);
2318 call_init_pointer(obj_main, preinit_addr[index]);
2324 * Call the finalization functions for each of the objects in "list"
2325 * belonging to the DAG of "root" and referenced once. If NULL "root"
2326 * is specified, every finalization function will be called regardless
2327 * of the reference count and the list elements won't be freed. All of
2328 * the objects are expected to have non-NULL fini functions.
2331 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2335 Elf_Addr *fini_addr;
2338 assert(root == NULL || root->refcount == 1);
2341 * Preserve the current error message since a fini function might
2342 * call into the dynamic linker and overwrite it.
2344 saved_msg = errmsg_save();
2346 STAILQ_FOREACH(elm, list, link) {
2347 if (root != NULL && (elm->obj->refcount != 1 ||
2348 objlist_find(&root->dagmembers, elm->obj) == NULL))
2350 /* Remove object from fini list to prevent recursive invocation. */
2351 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2353 * XXX: If a dlopen() call references an object while the
2354 * fini function is in progress, we might end up trying to
2355 * unload the referenced object in dlclose() or the object
2356 * won't be unloaded although its fini function has been
2359 lock_release(rtld_bind_lock, lockstate);
2362 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2363 * When this happens, DT_FINI_ARRAY is processed first.
2365 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2366 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2367 for (index = elm->obj->fini_array_num - 1; index >= 0;
2369 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2370 dbg("calling fini function for %s at %p",
2371 elm->obj->path, (void *)fini_addr[index]);
2372 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2373 (void *)fini_addr[index], 0, 0, elm->obj->path);
2374 call_initfini_pointer(elm->obj, fini_addr[index]);
2378 if (elm->obj->fini != (Elf_Addr)NULL) {
2379 dbg("calling fini function for %s at %p", elm->obj->path,
2380 (void *)elm->obj->fini);
2381 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2382 0, 0, elm->obj->path);
2383 call_initfini_pointer(elm->obj, elm->obj->fini);
2385 wlock_acquire(rtld_bind_lock, lockstate);
2386 /* No need to free anything if process is going down. */
2390 * We must restart the list traversal after every fini call
2391 * because a dlclose() call from the fini function or from
2392 * another thread might have modified the reference counts.
2396 } while (elm != NULL);
2397 errmsg_restore(saved_msg);
2401 * Call the initialization functions for each of the objects in
2402 * "list". All of the objects are expected to have non-NULL init
2406 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2411 Elf_Addr *init_addr;
2415 * Clean init_scanned flag so that objects can be rechecked and
2416 * possibly initialized earlier if any of vectors called below
2417 * cause the change by using dlopen.
2419 for (obj = obj_list; obj != NULL; obj = obj->next)
2420 obj->init_scanned = false;
2423 * Preserve the current error message since an init function might
2424 * call into the dynamic linker and overwrite it.
2426 saved_msg = errmsg_save();
2427 STAILQ_FOREACH(elm, list, link) {
2428 if (elm->obj->init_done) /* Initialized early. */
2431 * Race: other thread might try to use this object before current
2432 * one completes the initilization. Not much can be done here
2433 * without better locking.
2435 elm->obj->init_done = true;
2436 lock_release(rtld_bind_lock, lockstate);
2439 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2440 * When this happens, DT_INIT is processed first.
2442 if (elm->obj->init != (Elf_Addr)NULL) {
2443 dbg("calling init function for %s at %p", elm->obj->path,
2444 (void *)elm->obj->init);
2445 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2446 0, 0, elm->obj->path);
2447 call_initfini_pointer(elm->obj, elm->obj->init);
2449 init_addr = (Elf_Addr *)elm->obj->init_array;
2450 if (init_addr != NULL) {
2451 for (index = 0; index < elm->obj->init_array_num; index++) {
2452 if (init_addr[index] != 0 && init_addr[index] != 1) {
2453 dbg("calling init function for %s at %p", elm->obj->path,
2454 (void *)init_addr[index]);
2455 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2456 (void *)init_addr[index], 0, 0, elm->obj->path);
2457 call_init_pointer(elm->obj, init_addr[index]);
2461 wlock_acquire(rtld_bind_lock, lockstate);
2463 errmsg_restore(saved_msg);
2467 objlist_clear(Objlist *list)
2471 while (!STAILQ_EMPTY(list)) {
2472 elm = STAILQ_FIRST(list);
2473 STAILQ_REMOVE_HEAD(list, link);
2478 static Objlist_Entry *
2479 objlist_find(Objlist *list, const Obj_Entry *obj)
2483 STAILQ_FOREACH(elm, list, link)
2484 if (elm->obj == obj)
2490 objlist_init(Objlist *list)
2496 objlist_push_head(Objlist *list, Obj_Entry *obj)
2500 elm = NEW(Objlist_Entry);
2502 STAILQ_INSERT_HEAD(list, elm, link);
2506 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2510 elm = NEW(Objlist_Entry);
2512 STAILQ_INSERT_TAIL(list, elm, link);
2516 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2518 Objlist_Entry *elm, *listelm;
2520 STAILQ_FOREACH(listelm, list, link) {
2521 if (listelm->obj == listobj)
2524 elm = NEW(Objlist_Entry);
2526 if (listelm != NULL)
2527 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2529 STAILQ_INSERT_TAIL(list, elm, link);
2533 objlist_remove(Objlist *list, Obj_Entry *obj)
2537 if ((elm = objlist_find(list, obj)) != NULL) {
2538 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2544 * Relocate dag rooted in the specified object.
2545 * Returns 0 on success, or -1 on failure.
2549 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2550 int flags, RtldLockState *lockstate)
2556 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2557 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2566 * Relocate single object.
2567 * Returns 0 on success, or -1 on failure.
2570 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2571 int flags, RtldLockState *lockstate)
2576 obj->relocated = true;
2578 dbg("relocating \"%s\"", obj->path);
2580 if (obj->symtab == NULL || obj->strtab == NULL ||
2581 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2582 _rtld_error("%s: Shared object has no run-time symbol table",
2588 /* There are relocations to the write-protected text segment. */
2589 if (mprotect(obj->mapbase, obj->textsize,
2590 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2591 _rtld_error("%s: Cannot write-enable text segment: %s",
2592 obj->path, rtld_strerror(errno));
2597 /* Process the non-PLT non-IFUNC relocations. */
2598 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2601 if (obj->textrel) { /* Re-protected the text segment. */
2602 if (mprotect(obj->mapbase, obj->textsize,
2603 PROT_READ|PROT_EXEC) == -1) {
2604 _rtld_error("%s: Cannot write-protect text segment: %s",
2605 obj->path, rtld_strerror(errno));
2610 /* Set the special PLT or GOT entries. */
2613 /* Process the PLT relocations. */
2614 if (reloc_plt(obj) == -1)
2616 /* Relocate the jump slots if we are doing immediate binding. */
2617 if (obj->bind_now || bind_now)
2618 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2622 * Process the non-PLT IFUNC relocations. The relocations are
2623 * processed in two phases, because IFUNC resolvers may
2624 * reference other symbols, which must be readily processed
2625 * before resolvers are called.
2627 if (obj->non_plt_gnu_ifunc &&
2628 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2631 if (obj->relro_size > 0) {
2632 if (mprotect(obj->relro_page, obj->relro_size,
2634 _rtld_error("%s: Cannot enforce relro protection: %s",
2635 obj->path, rtld_strerror(errno));
2641 * Set up the magic number and version in the Obj_Entry. These
2642 * were checked in the crt1.o from the original ElfKit, so we
2643 * set them for backward compatibility.
2645 obj->magic = RTLD_MAGIC;
2646 obj->version = RTLD_VERSION;
2652 * Relocate newly-loaded shared objects. The argument is a pointer to
2653 * the Obj_Entry for the first such object. All objects from the first
2654 * to the end of the list of objects are relocated. Returns 0 on success,
2658 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2659 int flags, RtldLockState *lockstate)
2664 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2665 error = relocate_object(obj, bind_now, rtldobj, flags,
2674 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2675 * referencing STT_GNU_IFUNC symbols is postponed till the other
2676 * relocations are done. The indirect functions specified as
2677 * ifunc are allowed to call other symbols, so we need to have
2678 * objects relocated before asking for resolution from indirects.
2680 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2681 * instead of the usual lazy handling of PLT slots. It is
2682 * consistent with how GNU does it.
2685 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2686 RtldLockState *lockstate)
2688 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2690 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2691 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2697 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2698 RtldLockState *lockstate)
2702 for (obj = first; obj != NULL; obj = obj->next) {
2703 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2710 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2711 RtldLockState *lockstate)
2715 STAILQ_FOREACH(elm, list, link) {
2716 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2724 * Cleanup procedure. It will be called (by the atexit mechanism) just
2725 * before the process exits.
2730 RtldLockState lockstate;
2732 wlock_acquire(rtld_bind_lock, &lockstate);
2734 objlist_call_fini(&list_fini, NULL, &lockstate);
2735 /* No need to remove the items from the list, since we are exiting. */
2736 if (!libmap_disable)
2738 lock_release(rtld_bind_lock, &lockstate);
2742 * Iterate over a search path, translate each element, and invoke the
2743 * callback on the result.
2746 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2752 path += strspn(path, ":;");
2753 while (*path != '\0') {
2757 len = strcspn(path, ":;");
2758 trans = lm_findn(NULL, path, len);
2760 res = callback(trans, strlen(trans), arg);
2762 res = callback(path, len, arg);
2768 path += strspn(path, ":;");
2774 struct try_library_args {
2782 try_library_path(const char *dir, size_t dirlen, void *param)
2784 struct try_library_args *arg;
2787 if (*dir == '/' || trust) {
2790 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2793 pathname = arg->buffer;
2794 strncpy(pathname, dir, dirlen);
2795 pathname[dirlen] = '/';
2796 strcpy(pathname + dirlen + 1, arg->name);
2798 dbg(" Trying \"%s\"", pathname);
2799 if (access(pathname, F_OK) == 0) { /* We found it */
2800 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2801 strcpy(pathname, arg->buffer);
2809 search_library_path(const char *name, const char *path)
2812 struct try_library_args arg;
2818 arg.namelen = strlen(name);
2819 arg.buffer = xmalloc(PATH_MAX);
2820 arg.buflen = PATH_MAX;
2822 p = path_enumerate(path, try_library_path, &arg);
2831 * Finds the library with the given name using the directory descriptors
2832 * listed in the LD_LIBRARY_PATH_FDS environment variable.
2834 * Returns a freshly-opened close-on-exec file descriptor for the library,
2835 * or -1 if the library cannot be found.
2838 search_library_pathfds(const char *name, const char *path, int *fdp)
2840 char *envcopy, *fdstr, *found, *last_token;
2844 dbg("%s('%s', '%s', fdp)", __func__, name, path);
2846 /* Don't load from user-specified libdirs into setuid binaries. */
2850 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
2854 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
2855 if (name[0] == '/') {
2856 dbg("Absolute path (%s) passed to %s", name, __func__);
2861 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
2862 * copy of the path, as strtok_r rewrites separator tokens
2866 envcopy = xstrdup(path);
2867 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
2868 fdstr = strtok_r(NULL, ":", &last_token)) {
2869 dirfd = parse_libdir(fdstr);
2872 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
2875 len = strlen(fdstr) + strlen(name) + 3;
2876 found = xmalloc(len);
2877 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
2878 _rtld_error("error generating '%d/%s'",
2882 dbg("open('%s') => %d", found, fd);
2893 dlclose(void *handle)
2896 RtldLockState lockstate;
2898 wlock_acquire(rtld_bind_lock, &lockstate);
2899 root = dlcheck(handle);
2901 lock_release(rtld_bind_lock, &lockstate);
2904 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2907 /* Unreference the object and its dependencies. */
2908 root->dl_refcount--;
2910 if (root->refcount == 1) {
2912 * The object will be no longer referenced, so we must unload it.
2913 * First, call the fini functions.
2915 objlist_call_fini(&list_fini, root, &lockstate);
2919 /* Finish cleaning up the newly-unreferenced objects. */
2920 GDB_STATE(RT_DELETE,&root->linkmap);
2921 unload_object(root);
2922 GDB_STATE(RT_CONSISTENT,NULL);
2926 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2927 lock_release(rtld_bind_lock, &lockstate);
2934 char *msg = error_message;
2935 error_message = NULL;
2940 * This function is deprecated and has no effect.
2943 dllockinit(void *context,
2944 void *(*lock_create)(void *context),
2945 void (*rlock_acquire)(void *lock),
2946 void (*wlock_acquire)(void *lock),
2947 void (*lock_release)(void *lock),
2948 void (*lock_destroy)(void *lock),
2949 void (*context_destroy)(void *context))
2951 static void *cur_context;
2952 static void (*cur_context_destroy)(void *);
2954 /* Just destroy the context from the previous call, if necessary. */
2955 if (cur_context_destroy != NULL)
2956 cur_context_destroy(cur_context);
2957 cur_context = context;
2958 cur_context_destroy = context_destroy;
2962 dlopen(const char *name, int mode)
2965 return (rtld_dlopen(name, -1, mode));
2969 fdlopen(int fd, int mode)
2972 return (rtld_dlopen(NULL, fd, mode));
2976 rtld_dlopen(const char *name, int fd, int mode)
2978 RtldLockState lockstate;
2981 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2982 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2983 if (ld_tracing != NULL) {
2984 rlock_acquire(rtld_bind_lock, &lockstate);
2985 if (sigsetjmp(lockstate.env, 0) != 0)
2986 lock_upgrade(rtld_bind_lock, &lockstate);
2987 environ = (char **)*get_program_var_addr("environ", &lockstate);
2988 lock_release(rtld_bind_lock, &lockstate);
2990 lo_flags = RTLD_LO_DLOPEN;
2991 if (mode & RTLD_NODELETE)
2992 lo_flags |= RTLD_LO_NODELETE;
2993 if (mode & RTLD_NOLOAD)
2994 lo_flags |= RTLD_LO_NOLOAD;
2995 if (ld_tracing != NULL)
2996 lo_flags |= RTLD_LO_TRACE;
2998 return (dlopen_object(name, fd, obj_main, lo_flags,
2999 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3003 dlopen_cleanup(Obj_Entry *obj)
3008 if (obj->refcount == 0)
3013 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3014 int mode, RtldLockState *lockstate)
3016 Obj_Entry **old_obj_tail;
3019 RtldLockState mlockstate;
3022 objlist_init(&initlist);
3024 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3025 wlock_acquire(rtld_bind_lock, &mlockstate);
3026 lockstate = &mlockstate;
3028 GDB_STATE(RT_ADD,NULL);
3030 old_obj_tail = obj_tail;
3032 if (name == NULL && fd == -1) {
3036 obj = load_object(name, fd, refobj, lo_flags);
3041 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3042 objlist_push_tail(&list_global, obj);
3043 if (*old_obj_tail != NULL) { /* We loaded something new. */
3044 assert(*old_obj_tail == obj);
3045 result = load_needed_objects(obj,
3046 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3050 result = rtld_verify_versions(&obj->dagmembers);
3051 if (result != -1 && ld_tracing)
3053 if (result == -1 || relocate_object_dag(obj,
3054 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3055 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3057 dlopen_cleanup(obj);
3059 } else if (lo_flags & RTLD_LO_EARLY) {
3061 * Do not call the init functions for early loaded
3062 * filtees. The image is still not initialized enough
3065 * Our object is found by the global object list and
3066 * will be ordered among all init calls done right
3067 * before transferring control to main.
3070 /* Make list of init functions to call. */
3071 initlist_add_objects(obj, &obj->next, &initlist);
3074 * Process all no_delete or global objects here, given
3075 * them own DAGs to prevent their dependencies from being
3076 * unloaded. This has to be done after we have loaded all
3077 * of the dependencies, so that we do not miss any.
3083 * Bump the reference counts for objects on this DAG. If
3084 * this is the first dlopen() call for the object that was
3085 * already loaded as a dependency, initialize the dag
3091 if ((lo_flags & RTLD_LO_TRACE) != 0)
3094 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3095 obj->z_nodelete) && !obj->ref_nodel) {
3096 dbg("obj %s nodelete", obj->path);
3098 obj->z_nodelete = obj->ref_nodel = true;
3102 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3104 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3106 if (!(lo_flags & RTLD_LO_EARLY)) {
3107 map_stacks_exec(lockstate);
3110 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3111 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3113 objlist_clear(&initlist);
3114 dlopen_cleanup(obj);
3115 if (lockstate == &mlockstate)
3116 lock_release(rtld_bind_lock, lockstate);
3120 if (!(lo_flags & RTLD_LO_EARLY)) {
3121 /* Call the init functions. */
3122 objlist_call_init(&initlist, lockstate);
3124 objlist_clear(&initlist);
3125 if (lockstate == &mlockstate)
3126 lock_release(rtld_bind_lock, lockstate);
3129 trace_loaded_objects(obj);
3130 if (lockstate == &mlockstate)
3131 lock_release(rtld_bind_lock, lockstate);
3136 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3140 const Obj_Entry *obj, *defobj;
3143 RtldLockState lockstate;
3150 symlook_init(&req, name);
3152 req.flags = flags | SYMLOOK_IN_PLT;
3153 req.lockstate = &lockstate;
3155 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3156 rlock_acquire(rtld_bind_lock, &lockstate);
3157 if (sigsetjmp(lockstate.env, 0) != 0)
3158 lock_upgrade(rtld_bind_lock, &lockstate);
3159 if (handle == NULL || handle == RTLD_NEXT ||
3160 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3162 if ((obj = obj_from_addr(retaddr)) == NULL) {
3163 _rtld_error("Cannot determine caller's shared object");
3164 lock_release(rtld_bind_lock, &lockstate);
3165 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3168 if (handle == NULL) { /* Just the caller's shared object. */
3169 res = symlook_obj(&req, obj);
3172 defobj = req.defobj_out;
3174 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3175 handle == RTLD_SELF) { /* ... caller included */
3176 if (handle == RTLD_NEXT)
3178 for (; obj != NULL; obj = obj->next) {
3179 res = symlook_obj(&req, obj);
3182 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3184 defobj = req.defobj_out;
3185 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3191 * Search the dynamic linker itself, and possibly resolve the
3192 * symbol from there. This is how the application links to
3193 * dynamic linker services such as dlopen.
3195 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3196 res = symlook_obj(&req, &obj_rtld);
3199 defobj = req.defobj_out;
3203 assert(handle == RTLD_DEFAULT);
3204 res = symlook_default(&req, obj);
3206 defobj = req.defobj_out;
3211 if ((obj = dlcheck(handle)) == NULL) {
3212 lock_release(rtld_bind_lock, &lockstate);
3213 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3217 donelist_init(&donelist);
3218 if (obj->mainprog) {
3219 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3220 res = symlook_global(&req, &donelist);
3223 defobj = req.defobj_out;
3226 * Search the dynamic linker itself, and possibly resolve the
3227 * symbol from there. This is how the application links to
3228 * dynamic linker services such as dlopen.
3230 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3231 res = symlook_obj(&req, &obj_rtld);
3234 defobj = req.defobj_out;
3239 /* Search the whole DAG rooted at the given object. */
3240 res = symlook_list(&req, &obj->dagmembers, &donelist);
3243 defobj = req.defobj_out;
3249 lock_release(rtld_bind_lock, &lockstate);
3252 * The value required by the caller is derived from the value
3253 * of the symbol. this is simply the relocated value of the
3256 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3257 sym = make_function_pointer(def, defobj);
3258 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3259 sym = rtld_resolve_ifunc(defobj, def);
3260 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3261 ti.ti_module = defobj->tlsindex;
3262 ti.ti_offset = def->st_value;
3263 sym = __tls_get_addr(&ti);
3265 sym = defobj->relocbase + def->st_value;
3266 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3270 _rtld_error("Undefined symbol \"%s\"", name);
3271 lock_release(rtld_bind_lock, &lockstate);
3272 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3277 dlsym(void *handle, const char *name)
3279 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3284 dlfunc(void *handle, const char *name)
3291 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3297 dlvsym(void *handle, const char *name, const char *version)
3301 ventry.name = version;
3303 ventry.hash = elf_hash(version);
3305 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3310 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3312 const Obj_Entry *obj;
3313 RtldLockState lockstate;
3315 rlock_acquire(rtld_bind_lock, &lockstate);
3316 obj = obj_from_addr(addr);
3318 _rtld_error("No shared object contains address");
3319 lock_release(rtld_bind_lock, &lockstate);
3322 rtld_fill_dl_phdr_info(obj, phdr_info);
3323 lock_release(rtld_bind_lock, &lockstate);
3328 dladdr(const void *addr, Dl_info *info)
3330 const Obj_Entry *obj;
3333 unsigned long symoffset;
3334 RtldLockState lockstate;
3336 rlock_acquire(rtld_bind_lock, &lockstate);
3337 obj = obj_from_addr(addr);
3339 _rtld_error("No shared object contains address");
3340 lock_release(rtld_bind_lock, &lockstate);
3343 info->dli_fname = obj->path;
3344 info->dli_fbase = obj->mapbase;
3345 info->dli_saddr = (void *)0;
3346 info->dli_sname = NULL;
3349 * Walk the symbol list looking for the symbol whose address is
3350 * closest to the address sent in.
3352 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3353 def = obj->symtab + symoffset;
3356 * For skip the symbol if st_shndx is either SHN_UNDEF or
3359 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3363 * If the symbol is greater than the specified address, or if it
3364 * is further away from addr than the current nearest symbol,
3367 symbol_addr = obj->relocbase + def->st_value;
3368 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3371 /* Update our idea of the nearest symbol. */
3372 info->dli_sname = obj->strtab + def->st_name;
3373 info->dli_saddr = symbol_addr;
3376 if (info->dli_saddr == addr)
3379 lock_release(rtld_bind_lock, &lockstate);
3384 dlinfo(void *handle, int request, void *p)
3386 const Obj_Entry *obj;
3387 RtldLockState lockstate;
3390 rlock_acquire(rtld_bind_lock, &lockstate);
3392 if (handle == NULL || handle == RTLD_SELF) {
3395 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3396 if ((obj = obj_from_addr(retaddr)) == NULL)
3397 _rtld_error("Cannot determine caller's shared object");
3399 obj = dlcheck(handle);
3402 lock_release(rtld_bind_lock, &lockstate);
3408 case RTLD_DI_LINKMAP:
3409 *((struct link_map const **)p) = &obj->linkmap;
3411 case RTLD_DI_ORIGIN:
3412 error = rtld_dirname(obj->path, p);
3415 case RTLD_DI_SERINFOSIZE:
3416 case RTLD_DI_SERINFO:
3417 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3421 _rtld_error("Invalid request %d passed to dlinfo()", request);
3425 lock_release(rtld_bind_lock, &lockstate);
3431 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3434 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3435 phdr_info->dlpi_name = obj->path;
3436 phdr_info->dlpi_phdr = obj->phdr;
3437 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3438 phdr_info->dlpi_tls_modid = obj->tlsindex;
3439 phdr_info->dlpi_tls_data = obj->tlsinit;
3440 phdr_info->dlpi_adds = obj_loads;
3441 phdr_info->dlpi_subs = obj_loads - obj_count;
3445 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3447 struct dl_phdr_info phdr_info;
3448 const Obj_Entry *obj;
3449 RtldLockState bind_lockstate, phdr_lockstate;
3452 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3453 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3457 for (obj = obj_list; obj != NULL; obj = obj->next) {
3458 rtld_fill_dl_phdr_info(obj, &phdr_info);
3459 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3464 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3465 error = callback(&phdr_info, sizeof(phdr_info), param);
3468 lock_release(rtld_bind_lock, &bind_lockstate);
3469 lock_release(rtld_phdr_lock, &phdr_lockstate);
3475 fill_search_info(const char *dir, size_t dirlen, void *param)
3477 struct fill_search_info_args *arg;
3481 if (arg->request == RTLD_DI_SERINFOSIZE) {
3482 arg->serinfo->dls_cnt ++;
3483 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3485 struct dl_serpath *s_entry;
3487 s_entry = arg->serpath;
3488 s_entry->dls_name = arg->strspace;
3489 s_entry->dls_flags = arg->flags;
3491 strncpy(arg->strspace, dir, dirlen);
3492 arg->strspace[dirlen] = '\0';
3494 arg->strspace += dirlen + 1;
3502 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3504 struct dl_serinfo _info;
3505 struct fill_search_info_args args;
3507 args.request = RTLD_DI_SERINFOSIZE;
3508 args.serinfo = &_info;
3510 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3513 path_enumerate(obj->rpath, fill_search_info, &args);
3514 path_enumerate(ld_library_path, fill_search_info, &args);
3515 path_enumerate(obj->runpath, fill_search_info, &args);
3516 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3517 if (!obj->z_nodeflib)
3518 path_enumerate(ld_standard_library_path, fill_search_info, &args);
3521 if (request == RTLD_DI_SERINFOSIZE) {
3522 info->dls_size = _info.dls_size;
3523 info->dls_cnt = _info.dls_cnt;
3527 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3528 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3532 args.request = RTLD_DI_SERINFO;
3533 args.serinfo = info;
3534 args.serpath = &info->dls_serpath[0];
3535 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3537 args.flags = LA_SER_RUNPATH;
3538 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3541 args.flags = LA_SER_LIBPATH;
3542 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3545 args.flags = LA_SER_RUNPATH;
3546 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3549 args.flags = LA_SER_CONFIG;
3550 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3554 args.flags = LA_SER_DEFAULT;
3555 if (!obj->z_nodeflib &&
3556 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL)
3562 rtld_dirname(const char *path, char *bname)
3566 /* Empty or NULL string gets treated as "." */
3567 if (path == NULL || *path == '\0') {
3573 /* Strip trailing slashes */
3574 endp = path + strlen(path) - 1;
3575 while (endp > path && *endp == '/')
3578 /* Find the start of the dir */
3579 while (endp > path && *endp != '/')
3582 /* Either the dir is "/" or there are no slashes */
3584 bname[0] = *endp == '/' ? '/' : '.';
3590 } while (endp > path && *endp == '/');
3593 if (endp - path + 2 > PATH_MAX)
3595 _rtld_error("Filename is too long: %s", path);
3599 strncpy(bname, path, endp - path + 1);
3600 bname[endp - path + 1] = '\0';
3605 rtld_dirname_abs(const char *path, char *base)
3609 if (realpath(path, base) == NULL)
3611 dbg("%s -> %s", path, base);
3612 last = strrchr(base, '/');
3621 linkmap_add(Obj_Entry *obj)
3623 struct link_map *l = &obj->linkmap;
3624 struct link_map *prev;
3626 obj->linkmap.l_name = obj->path;
3627 obj->linkmap.l_addr = obj->mapbase;
3628 obj->linkmap.l_ld = obj->dynamic;
3630 /* GDB needs load offset on MIPS to use the symbols */
3631 obj->linkmap.l_offs = obj->relocbase;
3634 if (r_debug.r_map == NULL) {
3640 * Scan to the end of the list, but not past the entry for the
3641 * dynamic linker, which we want to keep at the very end.
3643 for (prev = r_debug.r_map;
3644 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3645 prev = prev->l_next)
3648 /* Link in the new entry. */
3650 l->l_next = prev->l_next;
3651 if (l->l_next != NULL)
3652 l->l_next->l_prev = l;
3657 linkmap_delete(Obj_Entry *obj)
3659 struct link_map *l = &obj->linkmap;
3661 if (l->l_prev == NULL) {
3662 if ((r_debug.r_map = l->l_next) != NULL)
3663 l->l_next->l_prev = NULL;
3667 if ((l->l_prev->l_next = l->l_next) != NULL)
3668 l->l_next->l_prev = l->l_prev;
3672 * Function for the debugger to set a breakpoint on to gain control.
3674 * The two parameters allow the debugger to easily find and determine
3675 * what the runtime loader is doing and to whom it is doing it.
3677 * When the loadhook trap is hit (r_debug_state, set at program
3678 * initialization), the arguments can be found on the stack:
3680 * +8 struct link_map *m
3681 * +4 struct r_debug *rd
3685 r_debug_state(struct r_debug* rd, struct link_map *m)
3688 * The following is a hack to force the compiler to emit calls to
3689 * this function, even when optimizing. If the function is empty,
3690 * the compiler is not obliged to emit any code for calls to it,
3691 * even when marked __noinline. However, gdb depends on those
3694 __compiler_membar();
3698 * A function called after init routines have completed. This can be used to
3699 * break before a program's entry routine is called, and can be used when
3700 * main is not available in the symbol table.
3703 _r_debug_postinit(struct link_map *m)
3706 /* See r_debug_state(). */
3707 __compiler_membar();
3711 * Get address of the pointer variable in the main program.
3712 * Prefer non-weak symbol over the weak one.
3714 static const void **
3715 get_program_var_addr(const char *name, RtldLockState *lockstate)
3720 symlook_init(&req, name);
3721 req.lockstate = lockstate;
3722 donelist_init(&donelist);
3723 if (symlook_global(&req, &donelist) != 0)
3725 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3726 return ((const void **)make_function_pointer(req.sym_out,
3728 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3729 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3731 return ((const void **)(req.defobj_out->relocbase +
3732 req.sym_out->st_value));
3736 * Set a pointer variable in the main program to the given value. This
3737 * is used to set key variables such as "environ" before any of the
3738 * init functions are called.
3741 set_program_var(const char *name, const void *value)
3745 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3746 dbg("\"%s\": *%p <-- %p", name, addr, value);
3752 * Search the global objects, including dependencies and main object,
3753 * for the given symbol.
3756 symlook_global(SymLook *req, DoneList *donelist)
3759 const Objlist_Entry *elm;
3762 symlook_init_from_req(&req1, req);
3764 /* Search all objects loaded at program start up. */
3765 if (req->defobj_out == NULL ||
3766 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3767 res = symlook_list(&req1, &list_main, donelist);
3768 if (res == 0 && (req->defobj_out == NULL ||
3769 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3770 req->sym_out = req1.sym_out;
3771 req->defobj_out = req1.defobj_out;
3772 assert(req->defobj_out != NULL);
3776 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3777 STAILQ_FOREACH(elm, &list_global, link) {
3778 if (req->defobj_out != NULL &&
3779 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3781 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3782 if (res == 0 && (req->defobj_out == NULL ||
3783 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3784 req->sym_out = req1.sym_out;
3785 req->defobj_out = req1.defobj_out;
3786 assert(req->defobj_out != NULL);
3790 return (req->sym_out != NULL ? 0 : ESRCH);
3794 * Given a symbol name in a referencing object, find the corresponding
3795 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3796 * no definition was found. Returns a pointer to the Obj_Entry of the
3797 * defining object via the reference parameter DEFOBJ_OUT.
3800 symlook_default(SymLook *req, const Obj_Entry *refobj)
3803 const Objlist_Entry *elm;
3807 donelist_init(&donelist);
3808 symlook_init_from_req(&req1, req);
3810 /* Look first in the referencing object if linked symbolically. */
3811 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3812 res = symlook_obj(&req1, refobj);
3814 req->sym_out = req1.sym_out;
3815 req->defobj_out = req1.defobj_out;
3816 assert(req->defobj_out != NULL);
3820 symlook_global(req, &donelist);
3822 /* Search all dlopened DAGs containing the referencing object. */
3823 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3824 if (req->sym_out != NULL &&
3825 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3827 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3828 if (res == 0 && (req->sym_out == NULL ||
3829 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3830 req->sym_out = req1.sym_out;
3831 req->defobj_out = req1.defobj_out;
3832 assert(req->defobj_out != NULL);
3837 * Search the dynamic linker itself, and possibly resolve the
3838 * symbol from there. This is how the application links to
3839 * dynamic linker services such as dlopen.
3841 if (req->sym_out == NULL ||
3842 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3843 res = symlook_obj(&req1, &obj_rtld);
3845 req->sym_out = req1.sym_out;
3846 req->defobj_out = req1.defobj_out;
3847 assert(req->defobj_out != NULL);
3851 return (req->sym_out != NULL ? 0 : ESRCH);
3855 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3858 const Obj_Entry *defobj;
3859 const Objlist_Entry *elm;
3865 STAILQ_FOREACH(elm, objlist, link) {
3866 if (donelist_check(dlp, elm->obj))
3868 symlook_init_from_req(&req1, req);
3869 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3870 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3872 defobj = req1.defobj_out;
3873 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3880 req->defobj_out = defobj;
3887 * Search the chain of DAGS cointed to by the given Needed_Entry
3888 * for a symbol of the given name. Each DAG is scanned completely
3889 * before advancing to the next one. Returns a pointer to the symbol,
3890 * or NULL if no definition was found.
3893 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3896 const Needed_Entry *n;
3897 const Obj_Entry *defobj;
3903 symlook_init_from_req(&req1, req);
3904 for (n = needed; n != NULL; n = n->next) {
3905 if (n->obj == NULL ||
3906 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3908 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3910 defobj = req1.defobj_out;
3911 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3917 req->defobj_out = defobj;
3924 * Search the symbol table of a single shared object for a symbol of
3925 * the given name and version, if requested. Returns a pointer to the
3926 * symbol, or NULL if no definition was found. If the object is
3927 * filter, return filtered symbol from filtee.
3929 * The symbol's hash value is passed in for efficiency reasons; that
3930 * eliminates many recomputations of the hash value.
3933 symlook_obj(SymLook *req, const Obj_Entry *obj)
3937 int flags, res, mres;
3940 * If there is at least one valid hash at this point, we prefer to
3941 * use the faster GNU version if available.
3943 if (obj->valid_hash_gnu)
3944 mres = symlook_obj1_gnu(req, obj);
3945 else if (obj->valid_hash_sysv)
3946 mres = symlook_obj1_sysv(req, obj);
3951 if (obj->needed_filtees != NULL) {
3952 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3953 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3954 donelist_init(&donelist);
3955 symlook_init_from_req(&req1, req);
3956 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3958 req->sym_out = req1.sym_out;
3959 req->defobj_out = req1.defobj_out;
3963 if (obj->needed_aux_filtees != NULL) {
3964 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3965 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3966 donelist_init(&donelist);
3967 symlook_init_from_req(&req1, req);
3968 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3970 req->sym_out = req1.sym_out;
3971 req->defobj_out = req1.defobj_out;
3979 /* Symbol match routine common to both hash functions */
3981 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3982 const unsigned long symnum)
3985 const Elf_Sym *symp;
3988 symp = obj->symtab + symnum;
3989 strp = obj->strtab + symp->st_name;
3991 switch (ELF_ST_TYPE(symp->st_info)) {
3997 if (symp->st_value == 0)
4001 if (symp->st_shndx != SHN_UNDEF)
4004 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4005 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4012 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4015 if (req->ventry == NULL) {
4016 if (obj->versyms != NULL) {
4017 verndx = VER_NDX(obj->versyms[symnum]);
4018 if (verndx > obj->vernum) {
4020 "%s: symbol %s references wrong version %d",
4021 obj->path, obj->strtab + symnum, verndx);
4025 * If we are not called from dlsym (i.e. this
4026 * is a normal relocation from unversioned
4027 * binary), accept the symbol immediately if
4028 * it happens to have first version after this
4029 * shared object became versioned. Otherwise,
4030 * if symbol is versioned and not hidden,
4031 * remember it. If it is the only symbol with
4032 * this name exported by the shared object, it
4033 * will be returned as a match by the calling
4034 * function. If symbol is global (verndx < 2)
4035 * accept it unconditionally.
4037 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4038 verndx == VER_NDX_GIVEN) {
4039 result->sym_out = symp;
4042 else if (verndx >= VER_NDX_GIVEN) {
4043 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4045 if (result->vsymp == NULL)
4046 result->vsymp = symp;
4052 result->sym_out = symp;
4055 if (obj->versyms == NULL) {
4056 if (object_match_name(obj, req->ventry->name)) {
4057 _rtld_error("%s: object %s should provide version %s "
4058 "for symbol %s", obj_rtld.path, obj->path,
4059 req->ventry->name, obj->strtab + symnum);
4063 verndx = VER_NDX(obj->versyms[symnum]);
4064 if (verndx > obj->vernum) {
4065 _rtld_error("%s: symbol %s references wrong version %d",
4066 obj->path, obj->strtab + symnum, verndx);
4069 if (obj->vertab[verndx].hash != req->ventry->hash ||
4070 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4072 * Version does not match. Look if this is a
4073 * global symbol and if it is not hidden. If
4074 * global symbol (verndx < 2) is available,
4075 * use it. Do not return symbol if we are
4076 * called by dlvsym, because dlvsym looks for
4077 * a specific version and default one is not
4078 * what dlvsym wants.
4080 if ((req->flags & SYMLOOK_DLSYM) ||
4081 (verndx >= VER_NDX_GIVEN) ||
4082 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4086 result->sym_out = symp;
4091 * Search for symbol using SysV hash function.
4092 * obj->buckets is known not to be NULL at this point; the test for this was
4093 * performed with the obj->valid_hash_sysv assignment.
4096 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4098 unsigned long symnum;
4099 Sym_Match_Result matchres;
4101 matchres.sym_out = NULL;
4102 matchres.vsymp = NULL;
4103 matchres.vcount = 0;
4105 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4106 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4107 if (symnum >= obj->nchains)
4108 return (ESRCH); /* Bad object */
4110 if (matched_symbol(req, obj, &matchres, symnum)) {
4111 req->sym_out = matchres.sym_out;
4112 req->defobj_out = obj;
4116 if (matchres.vcount == 1) {
4117 req->sym_out = matchres.vsymp;
4118 req->defobj_out = obj;
4124 /* Search for symbol using GNU hash function */
4126 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4128 Elf_Addr bloom_word;
4129 const Elf32_Word *hashval;
4131 Sym_Match_Result matchres;
4132 unsigned int h1, h2;
4133 unsigned long symnum;
4135 matchres.sym_out = NULL;
4136 matchres.vsymp = NULL;
4137 matchres.vcount = 0;
4139 /* Pick right bitmask word from Bloom filter array */
4140 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4141 obj->maskwords_bm_gnu];
4143 /* Calculate modulus word size of gnu hash and its derivative */
4144 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4145 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4147 /* Filter out the "definitely not in set" queries */
4148 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4151 /* Locate hash chain and corresponding value element*/
4152 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4155 hashval = &obj->chain_zero_gnu[bucket];
4157 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4158 symnum = hashval - obj->chain_zero_gnu;
4159 if (matched_symbol(req, obj, &matchres, symnum)) {
4160 req->sym_out = matchres.sym_out;
4161 req->defobj_out = obj;
4165 } while ((*hashval++ & 1) == 0);
4166 if (matchres.vcount == 1) {
4167 req->sym_out = matchres.vsymp;
4168 req->defobj_out = obj;
4175 trace_loaded_objects(Obj_Entry *obj)
4177 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4180 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4183 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4184 fmt1 = "\t%o => %p (%x)\n";
4186 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4187 fmt2 = "\t%o (%x)\n";
4189 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4191 for (; obj; obj = obj->next) {
4192 Needed_Entry *needed;
4196 if (list_containers && obj->needed != NULL)
4197 rtld_printf("%s:\n", obj->path);
4198 for (needed = obj->needed; needed; needed = needed->next) {
4199 if (needed->obj != NULL) {
4200 if (needed->obj->traced && !list_containers)
4202 needed->obj->traced = true;
4203 path = needed->obj->path;
4207 name = (char *)obj->strtab + needed->name;
4208 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4210 fmt = is_lib ? fmt1 : fmt2;
4211 while ((c = *fmt++) != '\0') {
4237 rtld_putstr(main_local);
4240 rtld_putstr(obj_main->path);
4247 rtld_printf("%d", sodp->sod_major);
4250 rtld_printf("%d", sodp->sod_minor);
4257 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4270 * Unload a dlopened object and its dependencies from memory and from
4271 * our data structures. It is assumed that the DAG rooted in the
4272 * object has already been unreferenced, and that the object has a
4273 * reference count of 0.
4276 unload_object(Obj_Entry *root)
4281 assert(root->refcount == 0);
4284 * Pass over the DAG removing unreferenced objects from
4285 * appropriate lists.
4287 unlink_object(root);
4289 /* Unmap all objects that are no longer referenced. */
4290 linkp = &obj_list->next;
4291 while ((obj = *linkp) != NULL) {
4292 if (obj->refcount == 0) {
4293 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4295 dbg("unloading \"%s\"", obj->path);
4296 unload_filtees(root);
4297 munmap(obj->mapbase, obj->mapsize);
4298 linkmap_delete(obj);
4309 unlink_object(Obj_Entry *root)
4313 if (root->refcount == 0) {
4314 /* Remove the object from the RTLD_GLOBAL list. */
4315 objlist_remove(&list_global, root);
4317 /* Remove the object from all objects' DAG lists. */
4318 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4319 objlist_remove(&elm->obj->dldags, root);
4320 if (elm->obj != root)
4321 unlink_object(elm->obj);
4327 ref_dag(Obj_Entry *root)
4331 assert(root->dag_inited);
4332 STAILQ_FOREACH(elm, &root->dagmembers, link)
4333 elm->obj->refcount++;
4337 unref_dag(Obj_Entry *root)
4341 assert(root->dag_inited);
4342 STAILQ_FOREACH(elm, &root->dagmembers, link)
4343 elm->obj->refcount--;
4347 * Common code for MD __tls_get_addr().
4349 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4351 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4353 Elf_Addr *newdtv, *dtv;
4354 RtldLockState lockstate;
4358 /* Check dtv generation in case new modules have arrived */
4359 if (dtv[0] != tls_dtv_generation) {
4360 wlock_acquire(rtld_bind_lock, &lockstate);
4361 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4363 if (to_copy > tls_max_index)
4364 to_copy = tls_max_index;
4365 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4366 newdtv[0] = tls_dtv_generation;
4367 newdtv[1] = tls_max_index;
4369 lock_release(rtld_bind_lock, &lockstate);
4370 dtv = *dtvp = newdtv;
4373 /* Dynamically allocate module TLS if necessary */
4374 if (dtv[index + 1] == 0) {
4375 /* Signal safe, wlock will block out signals. */
4376 wlock_acquire(rtld_bind_lock, &lockstate);
4377 if (!dtv[index + 1])
4378 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4379 lock_release(rtld_bind_lock, &lockstate);
4381 return ((void *)(dtv[index + 1] + offset));
4385 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4390 /* Check dtv generation in case new modules have arrived */
4391 if (__predict_true(dtv[0] == tls_dtv_generation &&
4392 dtv[index + 1] != 0))
4393 return ((void *)(dtv[index + 1] + offset));
4394 return (tls_get_addr_slow(dtvp, index, offset));
4397 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4398 defined(__powerpc__) || defined(__riscv__)
4401 * Allocate Static TLS using the Variant I method.
4404 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4413 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4416 assert(tcbsize >= TLS_TCB_SIZE);
4417 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4418 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4420 if (oldtcb != NULL) {
4421 memcpy(tls, oldtcb, tls_static_space);
4424 /* Adjust the DTV. */
4426 for (i = 0; i < dtv[1]; i++) {
4427 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4428 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4429 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4433 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4435 dtv[0] = tls_dtv_generation;
4436 dtv[1] = tls_max_index;
4438 for (obj = objs; obj; obj = obj->next) {
4439 if (obj->tlsoffset > 0) {
4440 addr = (Elf_Addr)tls + obj->tlsoffset;
4441 if (obj->tlsinitsize > 0)
4442 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4443 if (obj->tlssize > obj->tlsinitsize)
4444 memset((void*) (addr + obj->tlsinitsize), 0,
4445 obj->tlssize - obj->tlsinitsize);
4446 dtv[obj->tlsindex + 1] = addr;
4455 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4458 Elf_Addr tlsstart, tlsend;
4461 assert(tcbsize >= TLS_TCB_SIZE);
4463 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4464 tlsend = tlsstart + tls_static_space;
4466 dtv = *(Elf_Addr **)tlsstart;
4468 for (i = 0; i < dtvsize; i++) {
4469 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4470 free((void*)dtv[i+2]);
4479 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4482 * Allocate Static TLS using the Variant II method.
4485 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4488 size_t size, ralign;
4490 Elf_Addr *dtv, *olddtv;
4491 Elf_Addr segbase, oldsegbase, addr;
4495 if (tls_static_max_align > ralign)
4496 ralign = tls_static_max_align;
4497 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4499 assert(tcbsize >= 2*sizeof(Elf_Addr));
4500 tls = malloc_aligned(size, ralign);
4501 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4503 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4504 ((Elf_Addr*)segbase)[0] = segbase;
4505 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4507 dtv[0] = tls_dtv_generation;
4508 dtv[1] = tls_max_index;
4512 * Copy the static TLS block over whole.
4514 oldsegbase = (Elf_Addr) oldtls;
4515 memcpy((void *)(segbase - tls_static_space),
4516 (const void *)(oldsegbase - tls_static_space),
4520 * If any dynamic TLS blocks have been created tls_get_addr(),
4523 olddtv = ((Elf_Addr**)oldsegbase)[1];
4524 for (i = 0; i < olddtv[1]; i++) {
4525 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4526 dtv[i+2] = olddtv[i+2];
4532 * We assume that this block was the one we created with
4533 * allocate_initial_tls().
4535 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4537 for (obj = objs; obj; obj = obj->next) {
4538 if (obj->tlsoffset) {
4539 addr = segbase - obj->tlsoffset;
4540 memset((void*) (addr + obj->tlsinitsize),
4541 0, obj->tlssize - obj->tlsinitsize);
4543 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4544 dtv[obj->tlsindex + 1] = addr;
4549 return (void*) segbase;
4553 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4556 size_t size, ralign;
4558 Elf_Addr tlsstart, tlsend;
4561 * Figure out the size of the initial TLS block so that we can
4562 * find stuff which ___tls_get_addr() allocated dynamically.
4565 if (tls_static_max_align > ralign)
4566 ralign = tls_static_max_align;
4567 size = round(tls_static_space, ralign);
4569 dtv = ((Elf_Addr**)tls)[1];
4571 tlsend = (Elf_Addr) tls;
4572 tlsstart = tlsend - size;
4573 for (i = 0; i < dtvsize; i++) {
4574 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4575 free_aligned((void *)dtv[i + 2]);
4579 free_aligned((void *)tlsstart);
4586 * Allocate TLS block for module with given index.
4589 allocate_module_tls(int index)
4594 for (obj = obj_list; obj; obj = obj->next) {
4595 if (obj->tlsindex == index)
4599 _rtld_error("Can't find module with TLS index %d", index);
4603 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4604 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4605 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4611 allocate_tls_offset(Obj_Entry *obj)
4618 if (obj->tlssize == 0) {
4619 obj->tls_done = true;
4623 if (tls_last_offset == 0)
4624 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4626 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4627 obj->tlssize, obj->tlsalign);
4630 * If we have already fixed the size of the static TLS block, we
4631 * must stay within that size. When allocating the static TLS, we
4632 * leave a small amount of space spare to be used for dynamically
4633 * loading modules which use static TLS.
4635 if (tls_static_space != 0) {
4636 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4638 } else if (obj->tlsalign > tls_static_max_align) {
4639 tls_static_max_align = obj->tlsalign;
4642 tls_last_offset = obj->tlsoffset = off;
4643 tls_last_size = obj->tlssize;
4644 obj->tls_done = true;
4650 free_tls_offset(Obj_Entry *obj)
4654 * If we were the last thing to allocate out of the static TLS
4655 * block, we give our space back to the 'allocator'. This is a
4656 * simplistic workaround to allow libGL.so.1 to be loaded and
4657 * unloaded multiple times.
4659 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4660 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4661 tls_last_offset -= obj->tlssize;
4667 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4670 RtldLockState lockstate;
4672 wlock_acquire(rtld_bind_lock, &lockstate);
4673 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4674 lock_release(rtld_bind_lock, &lockstate);
4679 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4681 RtldLockState lockstate;
4683 wlock_acquire(rtld_bind_lock, &lockstate);
4684 free_tls(tcb, tcbsize, tcbalign);
4685 lock_release(rtld_bind_lock, &lockstate);
4689 object_add_name(Obj_Entry *obj, const char *name)
4695 entry = malloc(sizeof(Name_Entry) + len);
4697 if (entry != NULL) {
4698 strcpy(entry->name, name);
4699 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4704 object_match_name(const Obj_Entry *obj, const char *name)
4708 STAILQ_FOREACH(entry, &obj->names, link) {
4709 if (strcmp(name, entry->name) == 0)
4716 locate_dependency(const Obj_Entry *obj, const char *name)
4718 const Objlist_Entry *entry;
4719 const Needed_Entry *needed;
4721 STAILQ_FOREACH(entry, &list_main, link) {
4722 if (object_match_name(entry->obj, name))
4726 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4727 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4728 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4730 * If there is DT_NEEDED for the name we are looking for,
4731 * we are all set. Note that object might not be found if
4732 * dependency was not loaded yet, so the function can
4733 * return NULL here. This is expected and handled
4734 * properly by the caller.
4736 return (needed->obj);
4739 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4745 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4746 const Elf_Vernaux *vna)
4748 const Elf_Verdef *vd;
4749 const char *vername;
4751 vername = refobj->strtab + vna->vna_name;
4752 vd = depobj->verdef;
4754 _rtld_error("%s: version %s required by %s not defined",
4755 depobj->path, vername, refobj->path);
4759 if (vd->vd_version != VER_DEF_CURRENT) {
4760 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4761 depobj->path, vd->vd_version);
4764 if (vna->vna_hash == vd->vd_hash) {
4765 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4766 ((char *)vd + vd->vd_aux);
4767 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4770 if (vd->vd_next == 0)
4772 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4774 if (vna->vna_flags & VER_FLG_WEAK)
4776 _rtld_error("%s: version %s required by %s not found",
4777 depobj->path, vername, refobj->path);
4782 rtld_verify_object_versions(Obj_Entry *obj)
4784 const Elf_Verneed *vn;
4785 const Elf_Verdef *vd;
4786 const Elf_Verdaux *vda;
4787 const Elf_Vernaux *vna;
4788 const Obj_Entry *depobj;
4789 int maxvernum, vernum;
4791 if (obj->ver_checked)
4793 obj->ver_checked = true;
4797 * Walk over defined and required version records and figure out
4798 * max index used by any of them. Do very basic sanity checking
4802 while (vn != NULL) {
4803 if (vn->vn_version != VER_NEED_CURRENT) {
4804 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4805 obj->path, vn->vn_version);
4808 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4810 vernum = VER_NEED_IDX(vna->vna_other);
4811 if (vernum > maxvernum)
4813 if (vna->vna_next == 0)
4815 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4817 if (vn->vn_next == 0)
4819 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4823 while (vd != NULL) {
4824 if (vd->vd_version != VER_DEF_CURRENT) {
4825 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4826 obj->path, vd->vd_version);
4829 vernum = VER_DEF_IDX(vd->vd_ndx);
4830 if (vernum > maxvernum)
4832 if (vd->vd_next == 0)
4834 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4841 * Store version information in array indexable by version index.
4842 * Verify that object version requirements are satisfied along the
4845 obj->vernum = maxvernum + 1;
4846 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4849 while (vd != NULL) {
4850 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4851 vernum = VER_DEF_IDX(vd->vd_ndx);
4852 assert(vernum <= maxvernum);
4853 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4854 obj->vertab[vernum].hash = vd->vd_hash;
4855 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4856 obj->vertab[vernum].file = NULL;
4857 obj->vertab[vernum].flags = 0;
4859 if (vd->vd_next == 0)
4861 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4865 while (vn != NULL) {
4866 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4869 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4871 if (check_object_provided_version(obj, depobj, vna))
4873 vernum = VER_NEED_IDX(vna->vna_other);
4874 assert(vernum <= maxvernum);
4875 obj->vertab[vernum].hash = vna->vna_hash;
4876 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4877 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4878 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4879 VER_INFO_HIDDEN : 0;
4880 if (vna->vna_next == 0)
4882 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4884 if (vn->vn_next == 0)
4886 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4892 rtld_verify_versions(const Objlist *objlist)
4894 Objlist_Entry *entry;
4898 STAILQ_FOREACH(entry, objlist, link) {
4900 * Skip dummy objects or objects that have their version requirements
4903 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4905 if (rtld_verify_object_versions(entry->obj) == -1) {
4907 if (ld_tracing == NULL)
4911 if (rc == 0 || ld_tracing != NULL)
4912 rc = rtld_verify_object_versions(&obj_rtld);
4917 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4922 vernum = VER_NDX(obj->versyms[symnum]);
4923 if (vernum >= obj->vernum) {
4924 _rtld_error("%s: symbol %s has wrong verneed value %d",
4925 obj->path, obj->strtab + symnum, vernum);
4926 } else if (obj->vertab[vernum].hash != 0) {
4927 return &obj->vertab[vernum];
4934 _rtld_get_stack_prot(void)
4937 return (stack_prot);
4941 _rtld_is_dlopened(void *arg)
4944 RtldLockState lockstate;
4947 rlock_acquire(rtld_bind_lock, &lockstate);
4950 obj = obj_from_addr(arg);
4952 _rtld_error("No shared object contains address");
4953 lock_release(rtld_bind_lock, &lockstate);
4956 res = obj->dlopened ? 1 : 0;
4957 lock_release(rtld_bind_lock, &lockstate);
4962 map_stacks_exec(RtldLockState *lockstate)
4964 void (*thr_map_stacks_exec)(void);
4966 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4968 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4969 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4970 if (thr_map_stacks_exec != NULL) {
4971 stack_prot |= PROT_EXEC;
4972 thr_map_stacks_exec();
4977 symlook_init(SymLook *dst, const char *name)
4980 bzero(dst, sizeof(*dst));
4982 dst->hash = elf_hash(name);
4983 dst->hash_gnu = gnu_hash(name);
4987 symlook_init_from_req(SymLook *dst, const SymLook *src)
4990 dst->name = src->name;
4991 dst->hash = src->hash;
4992 dst->hash_gnu = src->hash_gnu;
4993 dst->ventry = src->ventry;
4994 dst->flags = src->flags;
4995 dst->defobj_out = NULL;
4996 dst->sym_out = NULL;
4997 dst->lockstate = src->lockstate;
5002 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5005 parse_libdir(const char *str)
5007 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5014 for (c = *str; c != '\0'; c = *++str) {
5015 if (c < '0' || c > '9')
5022 /* Make sure we actually parsed something. */
5024 _rtld_error("failed to parse directory FD from '%s'", str);
5031 * Overrides for libc_pic-provided functions.
5035 __getosreldate(void)
5045 oid[1] = KERN_OSRELDATE;
5047 len = sizeof(osrel);
5048 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5049 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5061 void (*__cleanup)(void);
5062 int __isthreaded = 0;
5063 int _thread_autoinit_dummy_decl = 1;
5066 * No unresolved symbols for rtld.
5069 __pthread_cxa_finalize(struct dl_phdr_info *a)
5074 __stack_chk_fail(void)
5077 _rtld_error("stack overflow detected; terminated");
5080 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5086 _rtld_error("buffer overflow detected; terminated");
5091 rtld_strerror(int errnum)
5094 if (errnum < 0 || errnum >= sys_nerr)
5095 return ("Unknown error");
5096 return (sys_errlist[errnum]);