2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
38 #error "GCC is needed to compile this file"
41 #include <sys/param.h>
42 #include <sys/mount.h>
45 #include <sys/sysctl.h>
47 #include <sys/utsname.h>
48 #include <sys/ktrace.h>
64 #include "rtld_printf.h"
68 #define PATH_RTLD "/libexec/ld-elf.so.1"
70 #define PATH_RTLD "/libexec/ld-elf32.so.1"
74 typedef void (*func_ptr_type)();
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 * Function declarations.
80 static const char *basename(const char *);
81 static void die(void) __dead2;
82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
83 const Elf_Dyn **, const Elf_Dyn **);
84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
86 static void digest_dynamic(Obj_Entry *, int);
87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
88 static Obj_Entry *dlcheck(void *);
89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
90 int lo_flags, int mode, RtldLockState *lockstate);
91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
93 static bool donelist_check(DoneList *, const Obj_Entry *);
94 static void errmsg_restore(char *);
95 static char *errmsg_save(void);
96 static void *fill_search_info(const char *, size_t, void *);
97 static char *find_library(const char *, const Obj_Entry *, int *);
98 static const char *gethints(bool);
99 static void init_dag(Obj_Entry *);
100 static void init_pagesizes(Elf_Auxinfo **aux_info);
101 static void init_rtld(caddr_t, Elf_Auxinfo **);
102 static void initlist_add_neededs(Needed_Entry *, Objlist *);
103 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
104 static void linkmap_add(Obj_Entry *);
105 static void linkmap_delete(Obj_Entry *);
106 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
107 static void unload_filtees(Obj_Entry *);
108 static int load_needed_objects(Obj_Entry *, int);
109 static int load_preload_objects(void);
110 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
111 static void map_stacks_exec(RtldLockState *);
112 static Obj_Entry *obj_from_addr(const void *);
113 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
114 static void objlist_call_init(Objlist *, RtldLockState *);
115 static void objlist_clear(Objlist *);
116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
117 static void objlist_init(Objlist *);
118 static void objlist_push_head(Objlist *, Obj_Entry *);
119 static void objlist_push_tail(Objlist *, Obj_Entry *);
120 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
121 static void objlist_remove(Objlist *, Obj_Entry *);
122 static int parse_libdir(const char *);
123 static void *path_enumerate(const char *, path_enum_proc, void *);
124 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
125 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
126 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
127 int flags, RtldLockState *lockstate);
128 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
130 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
131 int flags, RtldLockState *lockstate);
132 static int rtld_dirname(const char *, char *);
133 static int rtld_dirname_abs(const char *, char *);
134 static void *rtld_dlopen(const char *name, int fd, int mode);
135 static void rtld_exit(void);
136 static char *search_library_path(const char *, const char *);
137 static char *search_library_pathfds(const char *, const char *, int *);
138 static const void **get_program_var_addr(const char *, RtldLockState *);
139 static void set_program_var(const char *, const void *);
140 static int symlook_default(SymLook *, const Obj_Entry *refobj);
141 static int symlook_global(SymLook *, DoneList *);
142 static void symlook_init_from_req(SymLook *, const SymLook *);
143 static int symlook_list(SymLook *, const Objlist *, DoneList *);
144 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
145 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
146 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
147 static void trace_loaded_objects(Obj_Entry *);
148 static void unlink_object(Obj_Entry *);
149 static void unload_object(Obj_Entry *);
150 static void unref_dag(Obj_Entry *);
151 static void ref_dag(Obj_Entry *);
152 static char *origin_subst_one(char *, const char *, const char *, bool);
153 static char *origin_subst(char *, const char *);
154 static void preinit_main(void);
155 static int rtld_verify_versions(const Objlist *);
156 static int rtld_verify_object_versions(Obj_Entry *);
157 static void object_add_name(Obj_Entry *, const char *);
158 static int object_match_name(const Obj_Entry *, const char *);
159 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
160 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
161 struct dl_phdr_info *phdr_info);
162 static uint32_t gnu_hash(const char *);
163 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
164 const unsigned long);
166 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
167 void _r_debug_postinit(struct link_map *) __noinline;
169 int __sys_openat(int, const char *, int, ...);
174 static char *error_message; /* Message for dlerror(), or NULL */
175 struct r_debug r_debug; /* for GDB; */
176 static bool libmap_disable; /* Disable libmap */
177 static bool ld_loadfltr; /* Immediate filters processing */
178 static char *libmap_override; /* Maps to use in addition to libmap.conf */
179 static bool trust; /* False for setuid and setgid programs */
180 static bool dangerous_ld_env; /* True if environment variables have been
181 used to affect the libraries loaded */
182 static char *ld_bind_now; /* Environment variable for immediate binding */
183 static char *ld_debug; /* Environment variable for debugging */
184 static char *ld_library_path; /* Environment variable for search path */
185 static char *ld_library_dirs; /* Environment variable for library descriptors */
186 static char *ld_preload; /* Environment variable for libraries to
188 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
189 static char *ld_tracing; /* Called from ldd to print libs */
190 static char *ld_utrace; /* Use utrace() to log events. */
191 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
192 static Obj_Entry **obj_tail; /* Link field of last object in list */
193 static Obj_Entry *obj_main; /* The main program shared object */
194 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
195 static unsigned int obj_count; /* Number of objects in obj_list */
196 static unsigned int obj_loads; /* Number of objects in obj_list */
198 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
199 STAILQ_HEAD_INITIALIZER(list_global);
200 static Objlist list_main = /* Objects loaded at program startup */
201 STAILQ_HEAD_INITIALIZER(list_main);
202 static Objlist list_fini = /* Objects needing fini() calls */
203 STAILQ_HEAD_INITIALIZER(list_fini);
205 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
207 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
209 extern Elf_Dyn _DYNAMIC;
210 #pragma weak _DYNAMIC
211 #ifndef RTLD_IS_DYNAMIC
212 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
215 int npagesizes, osreldate;
218 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
220 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
221 static int max_stack_flags;
224 * Global declarations normally provided by crt1. The dynamic linker is
225 * not built with crt1, so we have to provide them ourselves.
231 * Used to pass argc, argv to init functions.
237 * Globals to control TLS allocation.
239 size_t tls_last_offset; /* Static TLS offset of last module */
240 size_t tls_last_size; /* Static TLS size of last module */
241 size_t tls_static_space; /* Static TLS space allocated */
242 size_t tls_static_max_align;
243 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
244 int tls_max_index = 1; /* Largest module index allocated */
246 bool ld_library_path_rpath = false;
249 * Fill in a DoneList with an allocation large enough to hold all of
250 * the currently-loaded objects. Keep this as a macro since it calls
251 * alloca and we want that to occur within the scope of the caller.
253 #define donelist_init(dlp) \
254 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
255 assert((dlp)->objs != NULL), \
256 (dlp)->num_alloc = obj_count, \
259 #define UTRACE_DLOPEN_START 1
260 #define UTRACE_DLOPEN_STOP 2
261 #define UTRACE_DLCLOSE_START 3
262 #define UTRACE_DLCLOSE_STOP 4
263 #define UTRACE_LOAD_OBJECT 5
264 #define UTRACE_UNLOAD_OBJECT 6
265 #define UTRACE_ADD_RUNDEP 7
266 #define UTRACE_PRELOAD_FINISHED 8
267 #define UTRACE_INIT_CALL 9
268 #define UTRACE_FINI_CALL 10
269 #define UTRACE_DLSYM_START 11
270 #define UTRACE_DLSYM_STOP 12
273 char sig[4]; /* 'RTLD' */
276 void *mapbase; /* Used for 'parent' and 'init/fini' */
278 int refcnt; /* Used for 'mode' */
279 char name[MAXPATHLEN];
282 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
283 if (ld_utrace != NULL) \
284 ld_utrace_log(e, h, mb, ms, r, n); \
288 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
289 int refcnt, const char *name)
291 struct utrace_rtld ut;
299 ut.mapbase = mapbase;
300 ut.mapsize = mapsize;
302 bzero(ut.name, sizeof(ut.name));
304 strlcpy(ut.name, name, sizeof(ut.name));
305 utrace(&ut, sizeof(ut));
309 * Main entry point for dynamic linking. The first argument is the
310 * stack pointer. The stack is expected to be laid out as described
311 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
312 * Specifically, the stack pointer points to a word containing
313 * ARGC. Following that in the stack is a null-terminated sequence
314 * of pointers to argument strings. Then comes a null-terminated
315 * sequence of pointers to environment strings. Finally, there is a
316 * sequence of "auxiliary vector" entries.
318 * The second argument points to a place to store the dynamic linker's
319 * exit procedure pointer and the third to a place to store the main
322 * The return value is the main program's entry point.
325 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
327 Elf_Auxinfo *aux_info[AT_COUNT];
335 Objlist_Entry *entry;
337 Obj_Entry **preload_tail;
338 Obj_Entry *last_interposer;
340 RtldLockState lockstate;
341 char *library_path_rpath;
346 * On entry, the dynamic linker itself has not been relocated yet.
347 * Be very careful not to reference any global data until after
348 * init_rtld has returned. It is OK to reference file-scope statics
349 * and string constants, and to call static and global functions.
352 /* Find the auxiliary vector on the stack. */
355 sp += argc + 1; /* Skip over arguments and NULL terminator */
357 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
359 aux = (Elf_Auxinfo *) sp;
361 /* Digest the auxiliary vector. */
362 for (i = 0; i < AT_COUNT; i++)
364 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
365 if (auxp->a_type < AT_COUNT)
366 aux_info[auxp->a_type] = auxp;
369 /* Initialize and relocate ourselves. */
370 assert(aux_info[AT_BASE] != NULL);
371 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
373 __progname = obj_rtld.path;
374 argv0 = argv[0] != NULL ? argv[0] : "(null)";
379 if (aux_info[AT_CANARY] != NULL &&
380 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
381 i = aux_info[AT_CANARYLEN]->a_un.a_val;
382 if (i > sizeof(__stack_chk_guard))
383 i = sizeof(__stack_chk_guard);
384 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
389 len = sizeof(__stack_chk_guard);
390 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
391 len != sizeof(__stack_chk_guard)) {
392 /* If sysctl was unsuccessful, use the "terminator canary". */
393 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
394 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
395 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
396 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
400 trust = !issetugid();
402 ld_bind_now = getenv(LD_ "BIND_NOW");
404 * If the process is tainted, then we un-set the dangerous environment
405 * variables. The process will be marked as tainted until setuid(2)
406 * is called. If any child process calls setuid(2) we do not want any
407 * future processes to honor the potentially un-safe variables.
410 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
411 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBRARY_PATH_FDS") ||
412 unsetenv(LD_ "LIBMAP_DISABLE") ||
413 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
414 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
415 _rtld_error("environment corrupt; aborting");
419 ld_debug = getenv(LD_ "DEBUG");
420 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
421 libmap_override = getenv(LD_ "LIBMAP");
422 ld_library_path = getenv(LD_ "LIBRARY_PATH");
423 ld_library_dirs = getenv(LD_ "LIBRARY_PATH_FDS");
424 ld_preload = getenv(LD_ "PRELOAD");
425 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
426 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
427 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
428 if (library_path_rpath != NULL) {
429 if (library_path_rpath[0] == 'y' ||
430 library_path_rpath[0] == 'Y' ||
431 library_path_rpath[0] == '1')
432 ld_library_path_rpath = true;
434 ld_library_path_rpath = false;
436 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
437 (ld_library_path != NULL) || (ld_preload != NULL) ||
438 (ld_elf_hints_path != NULL) || ld_loadfltr;
439 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
440 ld_utrace = getenv(LD_ "UTRACE");
442 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
443 ld_elf_hints_path = _PATH_ELF_HINTS;
445 if (ld_debug != NULL && *ld_debug != '\0')
447 dbg("%s is initialized, base address = %p", __progname,
448 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
449 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
450 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
452 dbg("initializing thread locks");
456 * Load the main program, or process its program header if it is
459 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
460 int fd = aux_info[AT_EXECFD]->a_un.a_val;
461 dbg("loading main program");
462 obj_main = map_object(fd, argv0, NULL);
464 if (obj_main == NULL)
466 max_stack_flags = obj->stack_flags;
467 } else { /* Main program already loaded. */
468 const Elf_Phdr *phdr;
472 dbg("processing main program's program header");
473 assert(aux_info[AT_PHDR] != NULL);
474 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
475 assert(aux_info[AT_PHNUM] != NULL);
476 phnum = aux_info[AT_PHNUM]->a_un.a_val;
477 assert(aux_info[AT_PHENT] != NULL);
478 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
479 assert(aux_info[AT_ENTRY] != NULL);
480 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
481 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
485 if (aux_info[AT_EXECPATH] != 0) {
487 char buf[MAXPATHLEN];
489 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
490 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
491 if (kexecpath[0] == '/')
492 obj_main->path = kexecpath;
493 else if (getcwd(buf, sizeof(buf)) == NULL ||
494 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
495 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
496 obj_main->path = xstrdup(argv0);
498 obj_main->path = xstrdup(buf);
500 dbg("No AT_EXECPATH");
501 obj_main->path = xstrdup(argv0);
503 dbg("obj_main path %s", obj_main->path);
504 obj_main->mainprog = true;
506 if (aux_info[AT_STACKPROT] != NULL &&
507 aux_info[AT_STACKPROT]->a_un.a_val != 0)
508 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
512 * Get the actual dynamic linker pathname from the executable if
513 * possible. (It should always be possible.) That ensures that
514 * gdb will find the right dynamic linker even if a non-standard
517 if (obj_main->interp != NULL &&
518 strcmp(obj_main->interp, obj_rtld.path) != 0) {
520 obj_rtld.path = xstrdup(obj_main->interp);
521 __progname = obj_rtld.path;
525 digest_dynamic(obj_main, 0);
526 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
527 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
528 obj_main->dynsymcount);
530 linkmap_add(obj_main);
531 linkmap_add(&obj_rtld);
533 /* Link the main program into the list of objects. */
534 *obj_tail = obj_main;
535 obj_tail = &obj_main->next;
539 /* Initialize a fake symbol for resolving undefined weak references. */
540 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
541 sym_zero.st_shndx = SHN_UNDEF;
542 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
545 libmap_disable = (bool)lm_init(libmap_override);
547 dbg("loading LD_PRELOAD libraries");
548 if (load_preload_objects() == -1)
550 preload_tail = obj_tail;
552 dbg("loading needed objects");
553 if (load_needed_objects(obj_main, 0) == -1)
556 /* Make a list of all objects loaded at startup. */
557 last_interposer = obj_main;
558 for (obj = obj_list; obj != NULL; obj = obj->next) {
559 if (obj->z_interpose && obj != obj_main) {
560 objlist_put_after(&list_main, last_interposer, obj);
561 last_interposer = obj;
563 objlist_push_tail(&list_main, obj);
568 dbg("checking for required versions");
569 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
572 if (ld_tracing) { /* We're done */
573 trace_loaded_objects(obj_main);
577 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
578 dump_relocations(obj_main);
583 * Processing tls relocations requires having the tls offsets
584 * initialized. Prepare offsets before starting initial
585 * relocation processing.
587 dbg("initializing initial thread local storage offsets");
588 STAILQ_FOREACH(entry, &list_main, link) {
590 * Allocate all the initial objects out of the static TLS
591 * block even if they didn't ask for it.
593 allocate_tls_offset(entry->obj);
596 if (relocate_objects(obj_main,
597 ld_bind_now != NULL && *ld_bind_now != '\0',
598 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
601 dbg("doing copy relocations");
602 if (do_copy_relocations(obj_main) == -1)
605 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
606 dump_relocations(obj_main);
611 * Setup TLS for main thread. This must be done after the
612 * relocations are processed, since tls initialization section
613 * might be the subject for relocations.
615 dbg("initializing initial thread local storage");
616 allocate_initial_tls(obj_list);
618 dbg("initializing key program variables");
619 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
620 set_program_var("environ", env);
621 set_program_var("__elf_aux_vector", aux);
623 /* Make a list of init functions to call. */
624 objlist_init(&initlist);
625 initlist_add_objects(obj_list, preload_tail, &initlist);
627 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
629 map_stacks_exec(NULL);
631 dbg("resolving ifuncs");
632 if (resolve_objects_ifunc(obj_main,
633 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
637 if (!obj_main->crt_no_init) {
639 * Make sure we don't call the main program's init and fini
640 * functions for binaries linked with old crt1 which calls
643 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
644 obj_main->preinit_array = obj_main->init_array =
645 obj_main->fini_array = (Elf_Addr)NULL;
648 wlock_acquire(rtld_bind_lock, &lockstate);
649 if (obj_main->crt_no_init)
651 objlist_call_init(&initlist, &lockstate);
652 _r_debug_postinit(&obj_main->linkmap);
653 objlist_clear(&initlist);
654 dbg("loading filtees");
655 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
656 if (ld_loadfltr || obj->z_loadfltr)
657 load_filtees(obj, 0, &lockstate);
659 lock_release(rtld_bind_lock, &lockstate);
661 dbg("transferring control to program entry point = %p", obj_main->entry);
663 /* Return the exit procedure and the program entry point. */
664 *exit_proc = rtld_exit;
666 return (func_ptr_type) obj_main->entry;
670 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
675 ptr = (void *)make_function_pointer(def, obj);
676 target = ((Elf_Addr (*)(void))ptr)();
677 return ((void *)target);
681 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
685 const Obj_Entry *defobj;
688 RtldLockState lockstate;
690 rlock_acquire(rtld_bind_lock, &lockstate);
691 if (sigsetjmp(lockstate.env, 0) != 0)
692 lock_upgrade(rtld_bind_lock, &lockstate);
694 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
696 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
698 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
699 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
703 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
704 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
706 target = (Elf_Addr)(defobj->relocbase + def->st_value);
708 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
709 defobj->strtab + def->st_name, basename(obj->path),
710 (void *)target, basename(defobj->path));
713 * Write the new contents for the jmpslot. Note that depending on
714 * architecture, the value which we need to return back to the
715 * lazy binding trampoline may or may not be the target
716 * address. The value returned from reloc_jmpslot() is the value
717 * that the trampoline needs.
719 target = reloc_jmpslot(where, target, defobj, obj, rel);
720 lock_release(rtld_bind_lock, &lockstate);
725 * Error reporting function. Use it like printf. If formats the message
726 * into a buffer, and sets things up so that the next call to dlerror()
727 * will return the message.
730 _rtld_error(const char *fmt, ...)
732 static char buf[512];
736 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
742 * Return a dynamically-allocated copy of the current error message, if any.
747 return error_message == NULL ? NULL : xstrdup(error_message);
751 * Restore the current error message from a copy which was previously saved
752 * by errmsg_save(). The copy is freed.
755 errmsg_restore(char *saved_msg)
757 if (saved_msg == NULL)
758 error_message = NULL;
760 _rtld_error("%s", saved_msg);
766 basename(const char *name)
768 const char *p = strrchr(name, '/');
769 return p != NULL ? p + 1 : name;
772 static struct utsname uts;
775 origin_subst_one(char *real, const char *kw, const char *subst,
778 char *p, *p1, *res, *resp;
779 int subst_len, kw_len, subst_count, old_len, new_len;
784 * First, count the number of the keyword occurences, to
785 * preallocate the final string.
787 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
794 * If the keyword is not found, just return.
796 if (subst_count == 0)
797 return (may_free ? real : xstrdup(real));
800 * There is indeed something to substitute. Calculate the
801 * length of the resulting string, and allocate it.
803 subst_len = strlen(subst);
804 old_len = strlen(real);
805 new_len = old_len + (subst_len - kw_len) * subst_count;
806 res = xmalloc(new_len + 1);
809 * Now, execute the substitution loop.
811 for (p = real, resp = res, *resp = '\0';;) {
814 /* Copy the prefix before keyword. */
815 memcpy(resp, p, p1 - p);
817 /* Keyword replacement. */
818 memcpy(resp, subst, subst_len);
826 /* Copy to the end of string and finish. */
834 origin_subst(char *real, const char *origin_path)
836 char *res1, *res2, *res3, *res4;
838 if (uts.sysname[0] == '\0') {
839 if (uname(&uts) != 0) {
840 _rtld_error("utsname failed: %d", errno);
844 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
845 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
846 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
847 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
854 const char *msg = dlerror();
858 rtld_fdputstr(STDERR_FILENO, msg);
859 rtld_fdputchar(STDERR_FILENO, '\n');
864 * Process a shared object's DYNAMIC section, and save the important
865 * information in its Obj_Entry structure.
868 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
869 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
872 Needed_Entry **needed_tail = &obj->needed;
873 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
874 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
875 const Elf_Hashelt *hashtab;
876 const Elf32_Word *hashval;
877 Elf32_Word bkt, nmaskwords;
879 int plttype = DT_REL;
885 obj->bind_now = false;
886 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
887 switch (dynp->d_tag) {
890 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
894 obj->relsize = dynp->d_un.d_val;
898 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
902 obj->pltrel = (const Elf_Rel *)
903 (obj->relocbase + dynp->d_un.d_ptr);
907 obj->pltrelsize = dynp->d_un.d_val;
911 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
915 obj->relasize = dynp->d_un.d_val;
919 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
923 plttype = dynp->d_un.d_val;
924 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
928 obj->symtab = (const Elf_Sym *)
929 (obj->relocbase + dynp->d_un.d_ptr);
933 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
937 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
941 obj->strsize = dynp->d_un.d_val;
945 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
950 obj->verneednum = dynp->d_un.d_val;
954 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
959 obj->verdefnum = dynp->d_un.d_val;
963 obj->versyms = (const Elf_Versym *)(obj->relocbase +
969 hashtab = (const Elf_Hashelt *)(obj->relocbase +
971 obj->nbuckets = hashtab[0];
972 obj->nchains = hashtab[1];
973 obj->buckets = hashtab + 2;
974 obj->chains = obj->buckets + obj->nbuckets;
975 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
976 obj->buckets != NULL;
982 hashtab = (const Elf_Hashelt *)(obj->relocbase +
984 obj->nbuckets_gnu = hashtab[0];
985 obj->symndx_gnu = hashtab[1];
986 nmaskwords = hashtab[2];
987 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
988 obj->maskwords_bm_gnu = nmaskwords - 1;
989 obj->shift2_gnu = hashtab[3];
990 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
991 obj->buckets_gnu = hashtab + 4 + bloom_size32;
992 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
994 /* Number of bitmask words is required to be power of 2 */
995 obj->valid_hash_gnu = powerof2(nmaskwords) &&
996 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1002 Needed_Entry *nep = NEW(Needed_Entry);
1003 nep->name = dynp->d_un.d_val;
1008 needed_tail = &nep->next;
1014 Needed_Entry *nep = NEW(Needed_Entry);
1015 nep->name = dynp->d_un.d_val;
1019 *needed_filtees_tail = nep;
1020 needed_filtees_tail = &nep->next;
1026 Needed_Entry *nep = NEW(Needed_Entry);
1027 nep->name = dynp->d_un.d_val;
1031 *needed_aux_filtees_tail = nep;
1032 needed_aux_filtees_tail = &nep->next;
1037 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1041 obj->textrel = true;
1045 obj->symbolic = true;
1050 * We have to wait until later to process this, because we
1051 * might not have gotten the address of the string table yet.
1061 *dyn_runpath = dynp;
1065 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1068 case DT_PREINIT_ARRAY:
1069 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1072 case DT_PREINIT_ARRAYSZ:
1073 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1077 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1080 case DT_INIT_ARRAYSZ:
1081 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1085 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1089 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1092 case DT_FINI_ARRAYSZ:
1093 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1097 * Don't process DT_DEBUG on MIPS as the dynamic section
1098 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1103 /* XXX - not implemented yet */
1105 dbg("Filling in DT_DEBUG entry");
1106 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1111 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1112 obj->z_origin = true;
1113 if (dynp->d_un.d_val & DF_SYMBOLIC)
1114 obj->symbolic = true;
1115 if (dynp->d_un.d_val & DF_TEXTREL)
1116 obj->textrel = true;
1117 if (dynp->d_un.d_val & DF_BIND_NOW)
1118 obj->bind_now = true;
1119 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1123 case DT_MIPS_LOCAL_GOTNO:
1124 obj->local_gotno = dynp->d_un.d_val;
1127 case DT_MIPS_SYMTABNO:
1128 obj->symtabno = dynp->d_un.d_val;
1131 case DT_MIPS_GOTSYM:
1132 obj->gotsym = dynp->d_un.d_val;
1135 case DT_MIPS_RLD_MAP:
1136 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1141 if (dynp->d_un.d_val & DF_1_NOOPEN)
1142 obj->z_noopen = true;
1143 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1144 obj->z_origin = true;
1145 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1147 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1148 obj->bind_now = true;
1149 if (dynp->d_un.d_val & DF_1_NODELETE)
1150 obj->z_nodelete = true;
1151 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1152 obj->z_loadfltr = true;
1153 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1154 obj->z_interpose = true;
1155 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1156 obj->z_nodeflib = true;
1161 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1168 obj->traced = false;
1170 if (plttype == DT_RELA) {
1171 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1173 obj->pltrelasize = obj->pltrelsize;
1174 obj->pltrelsize = 0;
1177 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1178 if (obj->valid_hash_sysv)
1179 obj->dynsymcount = obj->nchains;
1180 else if (obj->valid_hash_gnu) {
1181 obj->dynsymcount = 0;
1182 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1183 if (obj->buckets_gnu[bkt] == 0)
1185 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1188 while ((*hashval++ & 1u) == 0);
1190 obj->dynsymcount += obj->symndx_gnu;
1195 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1196 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1199 if (obj->z_origin && obj->origin_path == NULL) {
1200 obj->origin_path = xmalloc(PATH_MAX);
1201 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1205 if (dyn_runpath != NULL) {
1206 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1208 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1210 else if (dyn_rpath != NULL) {
1211 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1213 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1216 if (dyn_soname != NULL)
1217 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1221 digest_dynamic(Obj_Entry *obj, int early)
1223 const Elf_Dyn *dyn_rpath;
1224 const Elf_Dyn *dyn_soname;
1225 const Elf_Dyn *dyn_runpath;
1227 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1228 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1232 * Process a shared object's program header. This is used only for the
1233 * main program, when the kernel has already loaded the main program
1234 * into memory before calling the dynamic linker. It creates and
1235 * returns an Obj_Entry structure.
1238 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1241 const Elf_Phdr *phlimit = phdr + phnum;
1243 Elf_Addr note_start, note_end;
1247 for (ph = phdr; ph < phlimit; ph++) {
1248 if (ph->p_type != PT_PHDR)
1252 obj->phsize = ph->p_memsz;
1253 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1257 obj->stack_flags = PF_X | PF_R | PF_W;
1259 for (ph = phdr; ph < phlimit; ph++) {
1260 switch (ph->p_type) {
1263 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1267 if (nsegs == 0) { /* First load segment */
1268 obj->vaddrbase = trunc_page(ph->p_vaddr);
1269 obj->mapbase = obj->vaddrbase + obj->relocbase;
1270 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1272 } else { /* Last load segment */
1273 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1280 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1285 obj->tlssize = ph->p_memsz;
1286 obj->tlsalign = ph->p_align;
1287 obj->tlsinitsize = ph->p_filesz;
1288 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1292 obj->stack_flags = ph->p_flags;
1296 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1297 obj->relro_size = round_page(ph->p_memsz);
1301 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1302 note_end = note_start + ph->p_filesz;
1303 digest_notes(obj, note_start, note_end);
1308 _rtld_error("%s: too few PT_LOAD segments", path);
1317 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1319 const Elf_Note *note;
1320 const char *note_name;
1323 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1324 note = (const Elf_Note *)((const char *)(note + 1) +
1325 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1326 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1327 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1328 note->n_descsz != sizeof(int32_t))
1330 if (note->n_type != ABI_NOTETYPE &&
1331 note->n_type != CRT_NOINIT_NOTETYPE)
1333 note_name = (const char *)(note + 1);
1334 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1335 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1337 switch (note->n_type) {
1339 /* FreeBSD osrel note */
1340 p = (uintptr_t)(note + 1);
1341 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1342 obj->osrel = *(const int32_t *)(p);
1343 dbg("note osrel %d", obj->osrel);
1345 case CRT_NOINIT_NOTETYPE:
1346 /* FreeBSD 'crt does not call init' note */
1347 obj->crt_no_init = true;
1348 dbg("note crt_no_init");
1355 dlcheck(void *handle)
1359 for (obj = obj_list; obj != NULL; obj = obj->next)
1360 if (obj == (Obj_Entry *) handle)
1363 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1364 _rtld_error("Invalid shared object handle %p", handle);
1371 * If the given object is already in the donelist, return true. Otherwise
1372 * add the object to the list and return false.
1375 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1379 for (i = 0; i < dlp->num_used; i++)
1380 if (dlp->objs[i] == obj)
1383 * Our donelist allocation should always be sufficient. But if
1384 * our threads locking isn't working properly, more shared objects
1385 * could have been loaded since we allocated the list. That should
1386 * never happen, but we'll handle it properly just in case it does.
1388 if (dlp->num_used < dlp->num_alloc)
1389 dlp->objs[dlp->num_used++] = obj;
1394 * Hash function for symbol table lookup. Don't even think about changing
1395 * this. It is specified by the System V ABI.
1398 elf_hash(const char *name)
1400 const unsigned char *p = (const unsigned char *) name;
1401 unsigned long h = 0;
1404 while (*p != '\0') {
1405 h = (h << 4) + *p++;
1406 if ((g = h & 0xf0000000) != 0)
1414 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1415 * unsigned in case it's implemented with a wider type.
1418 gnu_hash(const char *s)
1424 for (c = *s; c != '\0'; c = *++s)
1426 return (h & 0xffffffff);
1431 * Find the library with the given name, and return its full pathname.
1432 * The returned string is dynamically allocated. Generates an error
1433 * message and returns NULL if the library cannot be found.
1435 * If the second argument is non-NULL, then it refers to an already-
1436 * loaded shared object, whose library search path will be searched.
1438 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1439 * descriptor (which is close-on-exec) will be passed out via the third
1442 * The search order is:
1443 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1444 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1446 * DT_RUNPATH in the referencing file
1447 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1449 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1451 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1454 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1458 bool nodeflib, objgiven;
1460 objgiven = refobj != NULL;
1461 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1462 if (xname[0] != '/' && !trust) {
1463 _rtld_error("Absolute pathname required for shared object \"%s\"",
1467 if (objgiven && refobj->z_origin) {
1468 return (origin_subst(__DECONST(char *, xname),
1469 refobj->origin_path));
1471 return (xstrdup(xname));
1475 if (libmap_disable || !objgiven ||
1476 (name = lm_find(refobj->path, xname)) == NULL)
1477 name = (char *)xname;
1479 dbg(" Searching for \"%s\"", name);
1482 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1483 * back to pre-conforming behaviour if user requested so with
1484 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1487 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1488 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1490 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1491 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1492 (pathname = search_library_path(name, gethints(false))) != NULL ||
1493 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1496 nodeflib = objgiven ? refobj->z_nodeflib : false;
1498 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1499 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1500 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1501 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1503 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1504 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1505 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1506 (objgiven && !nodeflib &&
1507 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1511 if (objgiven && refobj->path != NULL) {
1512 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1513 name, basename(refobj->path));
1515 _rtld_error("Shared object \"%s\" not found", name);
1521 * Given a symbol number in a referencing object, find the corresponding
1522 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1523 * no definition was found. Returns a pointer to the Obj_Entry of the
1524 * defining object via the reference parameter DEFOBJ_OUT.
1527 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1528 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1529 RtldLockState *lockstate)
1533 const Obj_Entry *defobj;
1539 * If we have already found this symbol, get the information from
1542 if (symnum >= refobj->dynsymcount)
1543 return NULL; /* Bad object */
1544 if (cache != NULL && cache[symnum].sym != NULL) {
1545 *defobj_out = cache[symnum].obj;
1546 return cache[symnum].sym;
1549 ref = refobj->symtab + symnum;
1550 name = refobj->strtab + ref->st_name;
1555 * We don't have to do a full scale lookup if the symbol is local.
1556 * We know it will bind to the instance in this load module; to
1557 * which we already have a pointer (ie ref). By not doing a lookup,
1558 * we not only improve performance, but it also avoids unresolvable
1559 * symbols when local symbols are not in the hash table. This has
1560 * been seen with the ia64 toolchain.
1562 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1563 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1564 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1567 symlook_init(&req, name);
1569 req.ventry = fetch_ventry(refobj, symnum);
1570 req.lockstate = lockstate;
1571 res = symlook_default(&req, refobj);
1574 defobj = req.defobj_out;
1582 * If we found no definition and the reference is weak, treat the
1583 * symbol as having the value zero.
1585 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1591 *defobj_out = defobj;
1592 /* Record the information in the cache to avoid subsequent lookups. */
1593 if (cache != NULL) {
1594 cache[symnum].sym = def;
1595 cache[symnum].obj = defobj;
1598 if (refobj != &obj_rtld)
1599 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1605 * Return the search path from the ldconfig hints file, reading it if
1606 * necessary. If nostdlib is true, then the default search paths are
1607 * not added to result.
1609 * Returns NULL if there are problems with the hints file,
1610 * or if the search path there is empty.
1613 gethints(bool nostdlib)
1615 static char *hints, *filtered_path;
1616 struct elfhints_hdr hdr;
1617 struct fill_search_info_args sargs, hargs;
1618 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1619 struct dl_serpath *SLPpath, *hintpath;
1621 unsigned int SLPndx, hintndx, fndx, fcount;
1626 /* First call, read the hints file */
1627 if (hints == NULL) {
1628 /* Keep from trying again in case the hints file is bad. */
1631 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1633 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1634 hdr.magic != ELFHINTS_MAGIC ||
1639 p = xmalloc(hdr.dirlistlen + 1);
1640 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1641 read(fd, p, hdr.dirlistlen + 1) !=
1642 (ssize_t)hdr.dirlistlen + 1) {
1652 * If caller agreed to receive list which includes the default
1653 * paths, we are done. Otherwise, if we still did not
1654 * calculated filtered result, do it now.
1657 return (hints[0] != '\0' ? hints : NULL);
1658 if (filtered_path != NULL)
1662 * Obtain the list of all configured search paths, and the
1663 * list of the default paths.
1665 * First estimate the size of the results.
1667 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1669 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1672 sargs.request = RTLD_DI_SERINFOSIZE;
1673 sargs.serinfo = &smeta;
1674 hargs.request = RTLD_DI_SERINFOSIZE;
1675 hargs.serinfo = &hmeta;
1677 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1678 path_enumerate(p, fill_search_info, &hargs);
1680 SLPinfo = xmalloc(smeta.dls_size);
1681 hintinfo = xmalloc(hmeta.dls_size);
1684 * Next fetch both sets of paths.
1686 sargs.request = RTLD_DI_SERINFO;
1687 sargs.serinfo = SLPinfo;
1688 sargs.serpath = &SLPinfo->dls_serpath[0];
1689 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1691 hargs.request = RTLD_DI_SERINFO;
1692 hargs.serinfo = hintinfo;
1693 hargs.serpath = &hintinfo->dls_serpath[0];
1694 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1696 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1697 path_enumerate(p, fill_search_info, &hargs);
1700 * Now calculate the difference between two sets, by excluding
1701 * standard paths from the full set.
1705 filtered_path = xmalloc(hdr.dirlistlen + 1);
1706 hintpath = &hintinfo->dls_serpath[0];
1707 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1709 SLPpath = &SLPinfo->dls_serpath[0];
1711 * Check each standard path against current.
1713 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1714 /* matched, skip the path */
1715 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1723 * Not matched against any standard path, add the path
1724 * to result. Separate consequtive paths with ':'.
1727 filtered_path[fndx] = ':';
1731 flen = strlen(hintpath->dls_name);
1732 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1735 filtered_path[fndx] = '\0';
1741 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1745 init_dag(Obj_Entry *root)
1747 const Needed_Entry *needed;
1748 const Objlist_Entry *elm;
1751 if (root->dag_inited)
1753 donelist_init(&donelist);
1755 /* Root object belongs to own DAG. */
1756 objlist_push_tail(&root->dldags, root);
1757 objlist_push_tail(&root->dagmembers, root);
1758 donelist_check(&donelist, root);
1761 * Add dependencies of root object to DAG in breadth order
1762 * by exploiting the fact that each new object get added
1763 * to the tail of the dagmembers list.
1765 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1766 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1767 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1769 objlist_push_tail(&needed->obj->dldags, root);
1770 objlist_push_tail(&root->dagmembers, needed->obj);
1773 root->dag_inited = true;
1777 process_nodelete(Obj_Entry *root)
1779 const Objlist_Entry *elm;
1782 * Walk over object DAG and process every dependent object that
1783 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1784 * which then should have its reference upped separately.
1786 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1787 if (elm->obj != NULL && elm->obj->z_nodelete &&
1788 !elm->obj->ref_nodel) {
1789 dbg("obj %s nodelete", elm->obj->path);
1792 elm->obj->ref_nodel = true;
1797 * Initialize the dynamic linker. The argument is the address at which
1798 * the dynamic linker has been mapped into memory. The primary task of
1799 * this function is to relocate the dynamic linker.
1802 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1804 Obj_Entry objtmp; /* Temporary rtld object */
1805 const Elf_Dyn *dyn_rpath;
1806 const Elf_Dyn *dyn_soname;
1807 const Elf_Dyn *dyn_runpath;
1809 #ifdef RTLD_INIT_PAGESIZES_EARLY
1810 /* The page size is required by the dynamic memory allocator. */
1811 init_pagesizes(aux_info);
1815 * Conjure up an Obj_Entry structure for the dynamic linker.
1817 * The "path" member can't be initialized yet because string constants
1818 * cannot yet be accessed. Below we will set it correctly.
1820 memset(&objtmp, 0, sizeof(objtmp));
1823 objtmp.mapbase = mapbase;
1825 objtmp.relocbase = mapbase;
1827 if (RTLD_IS_DYNAMIC()) {
1828 objtmp.dynamic = rtld_dynamic(&objtmp);
1829 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1830 assert(objtmp.needed == NULL);
1831 #if !defined(__mips__)
1832 /* MIPS has a bogus DT_TEXTREL. */
1833 assert(!objtmp.textrel);
1837 * Temporarily put the dynamic linker entry into the object list, so
1838 * that symbols can be found.
1841 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1844 /* Initialize the object list. */
1845 obj_tail = &obj_list;
1847 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1848 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1850 #ifndef RTLD_INIT_PAGESIZES_EARLY
1851 /* The page size is required by the dynamic memory allocator. */
1852 init_pagesizes(aux_info);
1855 if (aux_info[AT_OSRELDATE] != NULL)
1856 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1858 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1860 /* Replace the path with a dynamically allocated copy. */
1861 obj_rtld.path = xstrdup(PATH_RTLD);
1863 r_debug.r_brk = r_debug_state;
1864 r_debug.r_state = RT_CONSISTENT;
1868 * Retrieve the array of supported page sizes. The kernel provides the page
1869 * sizes in increasing order.
1872 init_pagesizes(Elf_Auxinfo **aux_info)
1874 static size_t psa[MAXPAGESIZES];
1878 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1880 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1881 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1884 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1887 /* As a fallback, retrieve the base page size. */
1888 size = sizeof(psa[0]);
1889 if (aux_info[AT_PAGESZ] != NULL) {
1890 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1894 mib[1] = HW_PAGESIZE;
1898 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1899 _rtld_error("sysctl for hw.pagesize(s) failed");
1905 npagesizes = size / sizeof(pagesizes[0]);
1906 /* Discard any invalid entries at the end of the array. */
1907 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1912 * Add the init functions from a needed object list (and its recursive
1913 * needed objects) to "list". This is not used directly; it is a helper
1914 * function for initlist_add_objects(). The write lock must be held
1915 * when this function is called.
1918 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1920 /* Recursively process the successor needed objects. */
1921 if (needed->next != NULL)
1922 initlist_add_neededs(needed->next, list);
1924 /* Process the current needed object. */
1925 if (needed->obj != NULL)
1926 initlist_add_objects(needed->obj, &needed->obj->next, list);
1930 * Scan all of the DAGs rooted in the range of objects from "obj" to
1931 * "tail" and add their init functions to "list". This recurses over
1932 * the DAGs and ensure the proper init ordering such that each object's
1933 * needed libraries are initialized before the object itself. At the
1934 * same time, this function adds the objects to the global finalization
1935 * list "list_fini" in the opposite order. The write lock must be
1936 * held when this function is called.
1939 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1942 if (obj->init_scanned || obj->init_done)
1944 obj->init_scanned = true;
1946 /* Recursively process the successor objects. */
1947 if (&obj->next != tail)
1948 initlist_add_objects(obj->next, tail, list);
1950 /* Recursively process the needed objects. */
1951 if (obj->needed != NULL)
1952 initlist_add_neededs(obj->needed, list);
1953 if (obj->needed_filtees != NULL)
1954 initlist_add_neededs(obj->needed_filtees, list);
1955 if (obj->needed_aux_filtees != NULL)
1956 initlist_add_neededs(obj->needed_aux_filtees, list);
1958 /* Add the object to the init list. */
1959 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1960 obj->init_array != (Elf_Addr)NULL)
1961 objlist_push_tail(list, obj);
1963 /* Add the object to the global fini list in the reverse order. */
1964 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1965 && !obj->on_fini_list) {
1966 objlist_push_head(&list_fini, obj);
1967 obj->on_fini_list = true;
1972 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1976 free_needed_filtees(Needed_Entry *n)
1978 Needed_Entry *needed, *needed1;
1980 for (needed = n; needed != NULL; needed = needed->next) {
1981 if (needed->obj != NULL) {
1982 dlclose(needed->obj);
1986 for (needed = n; needed != NULL; needed = needed1) {
1987 needed1 = needed->next;
1993 unload_filtees(Obj_Entry *obj)
1996 free_needed_filtees(obj->needed_filtees);
1997 obj->needed_filtees = NULL;
1998 free_needed_filtees(obj->needed_aux_filtees);
1999 obj->needed_aux_filtees = NULL;
2000 obj->filtees_loaded = false;
2004 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2005 RtldLockState *lockstate)
2008 for (; needed != NULL; needed = needed->next) {
2009 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2010 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2011 RTLD_LOCAL, lockstate);
2016 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2019 lock_restart_for_upgrade(lockstate);
2020 if (!obj->filtees_loaded) {
2021 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2022 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2023 obj->filtees_loaded = true;
2028 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2032 for (; needed != NULL; needed = needed->next) {
2033 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2034 flags & ~RTLD_LO_NOLOAD);
2035 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2042 * Given a shared object, traverse its list of needed objects, and load
2043 * each of them. Returns 0 on success. Generates an error message and
2044 * returns -1 on failure.
2047 load_needed_objects(Obj_Entry *first, int flags)
2051 for (obj = first; obj != NULL; obj = obj->next) {
2052 if (process_needed(obj, obj->needed, flags) == -1)
2059 load_preload_objects(void)
2061 char *p = ld_preload;
2063 static const char delim[] = " \t:;";
2068 p += strspn(p, delim);
2069 while (*p != '\0') {
2070 size_t len = strcspn(p, delim);
2075 obj = load_object(p, -1, NULL, 0);
2077 return -1; /* XXX - cleanup */
2078 obj->z_interpose = true;
2081 p += strspn(p, delim);
2083 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2088 printable_path(const char *path)
2091 return (path == NULL ? "<unknown>" : path);
2095 * Load a shared object into memory, if it is not already loaded. The
2096 * object may be specified by name or by user-supplied file descriptor
2097 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2100 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2104 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2113 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2114 if (object_match_name(obj, name))
2118 path = find_library(name, refobj, &fd);
2126 * search_library_pathfds() opens a fresh file descriptor for the
2127 * library, so there is no need to dup().
2129 } else if (fd_u == -1) {
2131 * If we didn't find a match by pathname, or the name is not
2132 * supplied, open the file and check again by device and inode.
2133 * This avoids false mismatches caused by multiple links or ".."
2136 * To avoid a race, we open the file and use fstat() rather than
2139 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2140 _rtld_error("Cannot open \"%s\"", path);
2145 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2147 _rtld_error("Cannot dup fd");
2152 if (fstat(fd, &sb) == -1) {
2153 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2158 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2159 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2161 if (obj != NULL && name != NULL) {
2162 object_add_name(obj, name);
2167 if (flags & RTLD_LO_NOLOAD) {
2173 /* First use of this object, so we must map it in */
2174 obj = do_load_object(fd, name, path, &sb, flags);
2183 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2190 * but first, make sure that environment variables haven't been
2191 * used to circumvent the noexec flag on a filesystem.
2193 if (dangerous_ld_env) {
2194 if (fstatfs(fd, &fs) != 0) {
2195 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2198 if (fs.f_flags & MNT_NOEXEC) {
2199 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2203 dbg("loading \"%s\"", printable_path(path));
2204 obj = map_object(fd, printable_path(path), sbp);
2209 * If DT_SONAME is present in the object, digest_dynamic2 already
2210 * added it to the object names.
2213 object_add_name(obj, name);
2215 digest_dynamic(obj, 0);
2216 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2217 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2218 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2220 dbg("refusing to load non-loadable \"%s\"", obj->path);
2221 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2222 munmap(obj->mapbase, obj->mapsize);
2227 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2229 obj_tail = &obj->next;
2232 linkmap_add(obj); /* for GDB & dlinfo() */
2233 max_stack_flags |= obj->stack_flags;
2235 dbg(" %p .. %p: %s", obj->mapbase,
2236 obj->mapbase + obj->mapsize - 1, obj->path);
2238 dbg(" WARNING: %s has impure text", obj->path);
2239 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2246 obj_from_addr(const void *addr)
2250 for (obj = obj_list; obj != NULL; obj = obj->next) {
2251 if (addr < (void *) obj->mapbase)
2253 if (addr < (void *) (obj->mapbase + obj->mapsize))
2262 Elf_Addr *preinit_addr;
2265 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2266 if (preinit_addr == NULL)
2269 for (index = 0; index < obj_main->preinit_array_num; index++) {
2270 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2271 dbg("calling preinit function for %s at %p", obj_main->path,
2272 (void *)preinit_addr[index]);
2273 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2274 0, 0, obj_main->path);
2275 call_init_pointer(obj_main, preinit_addr[index]);
2281 * Call the finalization functions for each of the objects in "list"
2282 * belonging to the DAG of "root" and referenced once. If NULL "root"
2283 * is specified, every finalization function will be called regardless
2284 * of the reference count and the list elements won't be freed. All of
2285 * the objects are expected to have non-NULL fini functions.
2288 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2292 Elf_Addr *fini_addr;
2295 assert(root == NULL || root->refcount == 1);
2298 * Preserve the current error message since a fini function might
2299 * call into the dynamic linker and overwrite it.
2301 saved_msg = errmsg_save();
2303 STAILQ_FOREACH(elm, list, link) {
2304 if (root != NULL && (elm->obj->refcount != 1 ||
2305 objlist_find(&root->dagmembers, elm->obj) == NULL))
2307 /* Remove object from fini list to prevent recursive invocation. */
2308 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2310 * XXX: If a dlopen() call references an object while the
2311 * fini function is in progress, we might end up trying to
2312 * unload the referenced object in dlclose() or the object
2313 * won't be unloaded although its fini function has been
2316 lock_release(rtld_bind_lock, lockstate);
2319 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2320 * When this happens, DT_FINI_ARRAY is processed first.
2322 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2323 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2324 for (index = elm->obj->fini_array_num - 1; index >= 0;
2326 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2327 dbg("calling fini function for %s at %p",
2328 elm->obj->path, (void *)fini_addr[index]);
2329 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2330 (void *)fini_addr[index], 0, 0, elm->obj->path);
2331 call_initfini_pointer(elm->obj, fini_addr[index]);
2335 if (elm->obj->fini != (Elf_Addr)NULL) {
2336 dbg("calling fini function for %s at %p", elm->obj->path,
2337 (void *)elm->obj->fini);
2338 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2339 0, 0, elm->obj->path);
2340 call_initfini_pointer(elm->obj, elm->obj->fini);
2342 wlock_acquire(rtld_bind_lock, lockstate);
2343 /* No need to free anything if process is going down. */
2347 * We must restart the list traversal after every fini call
2348 * because a dlclose() call from the fini function or from
2349 * another thread might have modified the reference counts.
2353 } while (elm != NULL);
2354 errmsg_restore(saved_msg);
2358 * Call the initialization functions for each of the objects in
2359 * "list". All of the objects are expected to have non-NULL init
2363 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2368 Elf_Addr *init_addr;
2372 * Clean init_scanned flag so that objects can be rechecked and
2373 * possibly initialized earlier if any of vectors called below
2374 * cause the change by using dlopen.
2376 for (obj = obj_list; obj != NULL; obj = obj->next)
2377 obj->init_scanned = false;
2380 * Preserve the current error message since an init function might
2381 * call into the dynamic linker and overwrite it.
2383 saved_msg = errmsg_save();
2384 STAILQ_FOREACH(elm, list, link) {
2385 if (elm->obj->init_done) /* Initialized early. */
2388 * Race: other thread might try to use this object before current
2389 * one completes the initilization. Not much can be done here
2390 * without better locking.
2392 elm->obj->init_done = true;
2393 lock_release(rtld_bind_lock, lockstate);
2396 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2397 * When this happens, DT_INIT is processed first.
2399 if (elm->obj->init != (Elf_Addr)NULL) {
2400 dbg("calling init function for %s at %p", elm->obj->path,
2401 (void *)elm->obj->init);
2402 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2403 0, 0, elm->obj->path);
2404 call_initfini_pointer(elm->obj, elm->obj->init);
2406 init_addr = (Elf_Addr *)elm->obj->init_array;
2407 if (init_addr != NULL) {
2408 for (index = 0; index < elm->obj->init_array_num; index++) {
2409 if (init_addr[index] != 0 && init_addr[index] != 1) {
2410 dbg("calling init function for %s at %p", elm->obj->path,
2411 (void *)init_addr[index]);
2412 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2413 (void *)init_addr[index], 0, 0, elm->obj->path);
2414 call_init_pointer(elm->obj, init_addr[index]);
2418 wlock_acquire(rtld_bind_lock, lockstate);
2420 errmsg_restore(saved_msg);
2424 objlist_clear(Objlist *list)
2428 while (!STAILQ_EMPTY(list)) {
2429 elm = STAILQ_FIRST(list);
2430 STAILQ_REMOVE_HEAD(list, link);
2435 static Objlist_Entry *
2436 objlist_find(Objlist *list, const Obj_Entry *obj)
2440 STAILQ_FOREACH(elm, list, link)
2441 if (elm->obj == obj)
2447 objlist_init(Objlist *list)
2453 objlist_push_head(Objlist *list, Obj_Entry *obj)
2457 elm = NEW(Objlist_Entry);
2459 STAILQ_INSERT_HEAD(list, elm, link);
2463 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2467 elm = NEW(Objlist_Entry);
2469 STAILQ_INSERT_TAIL(list, elm, link);
2473 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2475 Objlist_Entry *elm, *listelm;
2477 STAILQ_FOREACH(listelm, list, link) {
2478 if (listelm->obj == listobj)
2481 elm = NEW(Objlist_Entry);
2483 if (listelm != NULL)
2484 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2486 STAILQ_INSERT_TAIL(list, elm, link);
2490 objlist_remove(Objlist *list, Obj_Entry *obj)
2494 if ((elm = objlist_find(list, obj)) != NULL) {
2495 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2501 * Relocate dag rooted in the specified object.
2502 * Returns 0 on success, or -1 on failure.
2506 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2507 int flags, RtldLockState *lockstate)
2513 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2514 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2523 * Relocate single object.
2524 * Returns 0 on success, or -1 on failure.
2527 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2528 int flags, RtldLockState *lockstate)
2533 obj->relocated = true;
2535 dbg("relocating \"%s\"", obj->path);
2537 if (obj->symtab == NULL || obj->strtab == NULL ||
2538 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2539 _rtld_error("%s: Shared object has no run-time symbol table",
2545 /* There are relocations to the write-protected text segment. */
2546 if (mprotect(obj->mapbase, obj->textsize,
2547 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2548 _rtld_error("%s: Cannot write-enable text segment: %s",
2549 obj->path, rtld_strerror(errno));
2554 /* Process the non-PLT non-IFUNC relocations. */
2555 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2558 if (obj->textrel) { /* Re-protected the text segment. */
2559 if (mprotect(obj->mapbase, obj->textsize,
2560 PROT_READ|PROT_EXEC) == -1) {
2561 _rtld_error("%s: Cannot write-protect text segment: %s",
2562 obj->path, rtld_strerror(errno));
2567 /* Set the special PLT or GOT entries. */
2570 /* Process the PLT relocations. */
2571 if (reloc_plt(obj) == -1)
2573 /* Relocate the jump slots if we are doing immediate binding. */
2574 if (obj->bind_now || bind_now)
2575 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2579 * Process the non-PLT IFUNC relocations. The relocations are
2580 * processed in two phases, because IFUNC resolvers may
2581 * reference other symbols, which must be readily processed
2582 * before resolvers are called.
2584 if (obj->non_plt_gnu_ifunc &&
2585 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2588 if (obj->relro_size > 0) {
2589 if (mprotect(obj->relro_page, obj->relro_size,
2591 _rtld_error("%s: Cannot enforce relro protection: %s",
2592 obj->path, rtld_strerror(errno));
2598 * Set up the magic number and version in the Obj_Entry. These
2599 * were checked in the crt1.o from the original ElfKit, so we
2600 * set them for backward compatibility.
2602 obj->magic = RTLD_MAGIC;
2603 obj->version = RTLD_VERSION;
2609 * Relocate newly-loaded shared objects. The argument is a pointer to
2610 * the Obj_Entry for the first such object. All objects from the first
2611 * to the end of the list of objects are relocated. Returns 0 on success,
2615 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2616 int flags, RtldLockState *lockstate)
2621 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2622 error = relocate_object(obj, bind_now, rtldobj, flags,
2631 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2632 * referencing STT_GNU_IFUNC symbols is postponed till the other
2633 * relocations are done. The indirect functions specified as
2634 * ifunc are allowed to call other symbols, so we need to have
2635 * objects relocated before asking for resolution from indirects.
2637 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2638 * instead of the usual lazy handling of PLT slots. It is
2639 * consistent with how GNU does it.
2642 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2643 RtldLockState *lockstate)
2645 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2647 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2648 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2654 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2655 RtldLockState *lockstate)
2659 for (obj = first; obj != NULL; obj = obj->next) {
2660 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2667 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2668 RtldLockState *lockstate)
2672 STAILQ_FOREACH(elm, list, link) {
2673 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2681 * Cleanup procedure. It will be called (by the atexit mechanism) just
2682 * before the process exits.
2687 RtldLockState lockstate;
2689 wlock_acquire(rtld_bind_lock, &lockstate);
2691 objlist_call_fini(&list_fini, NULL, &lockstate);
2692 /* No need to remove the items from the list, since we are exiting. */
2693 if (!libmap_disable)
2695 lock_release(rtld_bind_lock, &lockstate);
2699 * Iterate over a search path, translate each element, and invoke the
2700 * callback on the result.
2703 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2709 path += strspn(path, ":;");
2710 while (*path != '\0') {
2714 len = strcspn(path, ":;");
2715 trans = lm_findn(NULL, path, len);
2717 res = callback(trans, strlen(trans), arg);
2719 res = callback(path, len, arg);
2725 path += strspn(path, ":;");
2731 struct try_library_args {
2739 try_library_path(const char *dir, size_t dirlen, void *param)
2741 struct try_library_args *arg;
2744 if (*dir == '/' || trust) {
2747 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2750 pathname = arg->buffer;
2751 strncpy(pathname, dir, dirlen);
2752 pathname[dirlen] = '/';
2753 strcpy(pathname + dirlen + 1, arg->name);
2755 dbg(" Trying \"%s\"", pathname);
2756 if (access(pathname, F_OK) == 0) { /* We found it */
2757 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2758 strcpy(pathname, arg->buffer);
2766 search_library_path(const char *name, const char *path)
2769 struct try_library_args arg;
2775 arg.namelen = strlen(name);
2776 arg.buffer = xmalloc(PATH_MAX);
2777 arg.buflen = PATH_MAX;
2779 p = path_enumerate(path, try_library_path, &arg);
2788 * Finds the library with the given name using the directory descriptors
2789 * listed in the LD_LIBRARY_PATH_FDS environment variable.
2791 * Returns a freshly-opened close-on-exec file descriptor for the library,
2792 * or -1 if the library cannot be found.
2795 search_library_pathfds(const char *name, const char *path, int *fdp)
2797 char *envcopy, *fdstr, *found, *last_token;
2801 dbg("%s('%s', '%s', fdp)", __func__, name, path);
2803 /* Don't load from user-specified libdirs into setuid binaries. */
2807 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
2811 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
2812 if (name[0] == '/') {
2813 dbg("Absolute path (%s) passed to %s", name, __func__);
2818 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
2819 * copy of the path, as strtok_r rewrites separator tokens
2823 envcopy = xstrdup(path);
2824 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
2825 fdstr = strtok_r(NULL, ":", &last_token)) {
2826 dirfd = parse_libdir(fdstr);
2829 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC);
2832 len = strlen(fdstr) + strlen(name) + 3;
2833 found = xmalloc(len);
2834 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
2835 _rtld_error("error generating '%d/%s'",
2839 dbg("open('%s') => %d", found, fd);
2850 dlclose(void *handle)
2853 RtldLockState lockstate;
2855 wlock_acquire(rtld_bind_lock, &lockstate);
2856 root = dlcheck(handle);
2858 lock_release(rtld_bind_lock, &lockstate);
2861 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2864 /* Unreference the object and its dependencies. */
2865 root->dl_refcount--;
2867 if (root->refcount == 1) {
2869 * The object will be no longer referenced, so we must unload it.
2870 * First, call the fini functions.
2872 objlist_call_fini(&list_fini, root, &lockstate);
2876 /* Finish cleaning up the newly-unreferenced objects. */
2877 GDB_STATE(RT_DELETE,&root->linkmap);
2878 unload_object(root);
2879 GDB_STATE(RT_CONSISTENT,NULL);
2883 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2884 lock_release(rtld_bind_lock, &lockstate);
2891 char *msg = error_message;
2892 error_message = NULL;
2897 * This function is deprecated and has no effect.
2900 dllockinit(void *context,
2901 void *(*lock_create)(void *context),
2902 void (*rlock_acquire)(void *lock),
2903 void (*wlock_acquire)(void *lock),
2904 void (*lock_release)(void *lock),
2905 void (*lock_destroy)(void *lock),
2906 void (*context_destroy)(void *context))
2908 static void *cur_context;
2909 static void (*cur_context_destroy)(void *);
2911 /* Just destroy the context from the previous call, if necessary. */
2912 if (cur_context_destroy != NULL)
2913 cur_context_destroy(cur_context);
2914 cur_context = context;
2915 cur_context_destroy = context_destroy;
2919 dlopen(const char *name, int mode)
2922 return (rtld_dlopen(name, -1, mode));
2926 fdlopen(int fd, int mode)
2929 return (rtld_dlopen(NULL, fd, mode));
2933 rtld_dlopen(const char *name, int fd, int mode)
2935 RtldLockState lockstate;
2938 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2939 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2940 if (ld_tracing != NULL) {
2941 rlock_acquire(rtld_bind_lock, &lockstate);
2942 if (sigsetjmp(lockstate.env, 0) != 0)
2943 lock_upgrade(rtld_bind_lock, &lockstate);
2944 environ = (char **)*get_program_var_addr("environ", &lockstate);
2945 lock_release(rtld_bind_lock, &lockstate);
2947 lo_flags = RTLD_LO_DLOPEN;
2948 if (mode & RTLD_NODELETE)
2949 lo_flags |= RTLD_LO_NODELETE;
2950 if (mode & RTLD_NOLOAD)
2951 lo_flags |= RTLD_LO_NOLOAD;
2952 if (ld_tracing != NULL)
2953 lo_flags |= RTLD_LO_TRACE;
2955 return (dlopen_object(name, fd, obj_main, lo_flags,
2956 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2960 dlopen_cleanup(Obj_Entry *obj)
2965 if (obj->refcount == 0)
2970 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2971 int mode, RtldLockState *lockstate)
2973 Obj_Entry **old_obj_tail;
2976 RtldLockState mlockstate;
2979 objlist_init(&initlist);
2981 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2982 wlock_acquire(rtld_bind_lock, &mlockstate);
2983 lockstate = &mlockstate;
2985 GDB_STATE(RT_ADD,NULL);
2987 old_obj_tail = obj_tail;
2989 if (name == NULL && fd == -1) {
2993 obj = load_object(name, fd, refobj, lo_flags);
2998 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2999 objlist_push_tail(&list_global, obj);
3000 if (*old_obj_tail != NULL) { /* We loaded something new. */
3001 assert(*old_obj_tail == obj);
3002 result = load_needed_objects(obj,
3003 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3007 result = rtld_verify_versions(&obj->dagmembers);
3008 if (result != -1 && ld_tracing)
3010 if (result == -1 || relocate_object_dag(obj,
3011 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3012 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3014 dlopen_cleanup(obj);
3016 } else if (lo_flags & RTLD_LO_EARLY) {
3018 * Do not call the init functions for early loaded
3019 * filtees. The image is still not initialized enough
3022 * Our object is found by the global object list and
3023 * will be ordered among all init calls done right
3024 * before transferring control to main.
3027 /* Make list of init functions to call. */
3028 initlist_add_objects(obj, &obj->next, &initlist);
3031 * Process all no_delete objects here, given them own
3032 * DAGs to prevent their dependencies from being unloaded.
3033 * This has to be done after we have loaded all of the
3034 * dependencies, so that we do not miss any.
3037 process_nodelete(obj);
3040 * Bump the reference counts for objects on this DAG. If
3041 * this is the first dlopen() call for the object that was
3042 * already loaded as a dependency, initialize the dag
3048 if ((lo_flags & RTLD_LO_TRACE) != 0)
3051 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3052 obj->z_nodelete) && !obj->ref_nodel) {
3053 dbg("obj %s nodelete", obj->path);
3055 obj->z_nodelete = obj->ref_nodel = true;
3059 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3061 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3063 if (!(lo_flags & RTLD_LO_EARLY)) {
3064 map_stacks_exec(lockstate);
3067 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3068 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3070 objlist_clear(&initlist);
3071 dlopen_cleanup(obj);
3072 if (lockstate == &mlockstate)
3073 lock_release(rtld_bind_lock, lockstate);
3077 if (!(lo_flags & RTLD_LO_EARLY)) {
3078 /* Call the init functions. */
3079 objlist_call_init(&initlist, lockstate);
3081 objlist_clear(&initlist);
3082 if (lockstate == &mlockstate)
3083 lock_release(rtld_bind_lock, lockstate);
3086 trace_loaded_objects(obj);
3087 if (lockstate == &mlockstate)
3088 lock_release(rtld_bind_lock, lockstate);
3093 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3097 const Obj_Entry *obj, *defobj;
3100 RtldLockState lockstate;
3107 symlook_init(&req, name);
3109 req.flags = flags | SYMLOOK_IN_PLT;
3110 req.lockstate = &lockstate;
3112 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3113 rlock_acquire(rtld_bind_lock, &lockstate);
3114 if (sigsetjmp(lockstate.env, 0) != 0)
3115 lock_upgrade(rtld_bind_lock, &lockstate);
3116 if (handle == NULL || handle == RTLD_NEXT ||
3117 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3119 if ((obj = obj_from_addr(retaddr)) == NULL) {
3120 _rtld_error("Cannot determine caller's shared object");
3121 lock_release(rtld_bind_lock, &lockstate);
3122 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3125 if (handle == NULL) { /* Just the caller's shared object. */
3126 res = symlook_obj(&req, obj);
3129 defobj = req.defobj_out;
3131 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3132 handle == RTLD_SELF) { /* ... caller included */
3133 if (handle == RTLD_NEXT)
3135 for (; obj != NULL; obj = obj->next) {
3136 res = symlook_obj(&req, obj);
3139 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3141 defobj = req.defobj_out;
3142 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3148 * Search the dynamic linker itself, and possibly resolve the
3149 * symbol from there. This is how the application links to
3150 * dynamic linker services such as dlopen.
3152 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3153 res = symlook_obj(&req, &obj_rtld);
3156 defobj = req.defobj_out;
3160 assert(handle == RTLD_DEFAULT);
3161 res = symlook_default(&req, obj);
3163 defobj = req.defobj_out;
3168 if ((obj = dlcheck(handle)) == NULL) {
3169 lock_release(rtld_bind_lock, &lockstate);
3170 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3174 donelist_init(&donelist);
3175 if (obj->mainprog) {
3176 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3177 res = symlook_global(&req, &donelist);
3180 defobj = req.defobj_out;
3183 * Search the dynamic linker itself, and possibly resolve the
3184 * symbol from there. This is how the application links to
3185 * dynamic linker services such as dlopen.
3187 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3188 res = symlook_obj(&req, &obj_rtld);
3191 defobj = req.defobj_out;
3196 /* Search the whole DAG rooted at the given object. */
3197 res = symlook_list(&req, &obj->dagmembers, &donelist);
3200 defobj = req.defobj_out;
3206 lock_release(rtld_bind_lock, &lockstate);
3209 * The value required by the caller is derived from the value
3210 * of the symbol. this is simply the relocated value of the
3213 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3214 sym = make_function_pointer(def, defobj);
3215 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3216 sym = rtld_resolve_ifunc(defobj, def);
3217 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3218 ti.ti_module = defobj->tlsindex;
3219 ti.ti_offset = def->st_value;
3220 sym = __tls_get_addr(&ti);
3222 sym = defobj->relocbase + def->st_value;
3223 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3227 _rtld_error("Undefined symbol \"%s\"", name);
3228 lock_release(rtld_bind_lock, &lockstate);
3229 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3234 dlsym(void *handle, const char *name)
3236 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3241 dlfunc(void *handle, const char *name)
3248 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3254 dlvsym(void *handle, const char *name, const char *version)
3258 ventry.name = version;
3260 ventry.hash = elf_hash(version);
3262 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3267 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3269 const Obj_Entry *obj;
3270 RtldLockState lockstate;
3272 rlock_acquire(rtld_bind_lock, &lockstate);
3273 obj = obj_from_addr(addr);
3275 _rtld_error("No shared object contains address");
3276 lock_release(rtld_bind_lock, &lockstate);
3279 rtld_fill_dl_phdr_info(obj, phdr_info);
3280 lock_release(rtld_bind_lock, &lockstate);
3285 dladdr(const void *addr, Dl_info *info)
3287 const Obj_Entry *obj;
3290 unsigned long symoffset;
3291 RtldLockState lockstate;
3293 rlock_acquire(rtld_bind_lock, &lockstate);
3294 obj = obj_from_addr(addr);
3296 _rtld_error("No shared object contains address");
3297 lock_release(rtld_bind_lock, &lockstate);
3300 info->dli_fname = obj->path;
3301 info->dli_fbase = obj->mapbase;
3302 info->dli_saddr = (void *)0;
3303 info->dli_sname = NULL;
3306 * Walk the symbol list looking for the symbol whose address is
3307 * closest to the address sent in.
3309 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3310 def = obj->symtab + symoffset;
3313 * For skip the symbol if st_shndx is either SHN_UNDEF or
3316 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3320 * If the symbol is greater than the specified address, or if it
3321 * is further away from addr than the current nearest symbol,
3324 symbol_addr = obj->relocbase + def->st_value;
3325 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3328 /* Update our idea of the nearest symbol. */
3329 info->dli_sname = obj->strtab + def->st_name;
3330 info->dli_saddr = symbol_addr;
3333 if (info->dli_saddr == addr)
3336 lock_release(rtld_bind_lock, &lockstate);
3341 dlinfo(void *handle, int request, void *p)
3343 const Obj_Entry *obj;
3344 RtldLockState lockstate;
3347 rlock_acquire(rtld_bind_lock, &lockstate);
3349 if (handle == NULL || handle == RTLD_SELF) {
3352 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3353 if ((obj = obj_from_addr(retaddr)) == NULL)
3354 _rtld_error("Cannot determine caller's shared object");
3356 obj = dlcheck(handle);
3359 lock_release(rtld_bind_lock, &lockstate);
3365 case RTLD_DI_LINKMAP:
3366 *((struct link_map const **)p) = &obj->linkmap;
3368 case RTLD_DI_ORIGIN:
3369 error = rtld_dirname(obj->path, p);
3372 case RTLD_DI_SERINFOSIZE:
3373 case RTLD_DI_SERINFO:
3374 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3378 _rtld_error("Invalid request %d passed to dlinfo()", request);
3382 lock_release(rtld_bind_lock, &lockstate);
3388 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3391 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3392 phdr_info->dlpi_name = obj->path;
3393 phdr_info->dlpi_phdr = obj->phdr;
3394 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3395 phdr_info->dlpi_tls_modid = obj->tlsindex;
3396 phdr_info->dlpi_tls_data = obj->tlsinit;
3397 phdr_info->dlpi_adds = obj_loads;
3398 phdr_info->dlpi_subs = obj_loads - obj_count;
3402 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3404 struct dl_phdr_info phdr_info;
3405 const Obj_Entry *obj;
3406 RtldLockState bind_lockstate, phdr_lockstate;
3409 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3410 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3414 for (obj = obj_list; obj != NULL; obj = obj->next) {
3415 rtld_fill_dl_phdr_info(obj, &phdr_info);
3416 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3421 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3422 error = callback(&phdr_info, sizeof(phdr_info), param);
3425 lock_release(rtld_bind_lock, &bind_lockstate);
3426 lock_release(rtld_phdr_lock, &phdr_lockstate);
3432 fill_search_info(const char *dir, size_t dirlen, void *param)
3434 struct fill_search_info_args *arg;
3438 if (arg->request == RTLD_DI_SERINFOSIZE) {
3439 arg->serinfo->dls_cnt ++;
3440 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3442 struct dl_serpath *s_entry;
3444 s_entry = arg->serpath;
3445 s_entry->dls_name = arg->strspace;
3446 s_entry->dls_flags = arg->flags;
3448 strncpy(arg->strspace, dir, dirlen);
3449 arg->strspace[dirlen] = '\0';
3451 arg->strspace += dirlen + 1;
3459 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3461 struct dl_serinfo _info;
3462 struct fill_search_info_args args;
3464 args.request = RTLD_DI_SERINFOSIZE;
3465 args.serinfo = &_info;
3467 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3470 path_enumerate(obj->rpath, fill_search_info, &args);
3471 path_enumerate(ld_library_path, fill_search_info, &args);
3472 path_enumerate(obj->runpath, fill_search_info, &args);
3473 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3474 if (!obj->z_nodeflib)
3475 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3478 if (request == RTLD_DI_SERINFOSIZE) {
3479 info->dls_size = _info.dls_size;
3480 info->dls_cnt = _info.dls_cnt;
3484 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3485 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3489 args.request = RTLD_DI_SERINFO;
3490 args.serinfo = info;
3491 args.serpath = &info->dls_serpath[0];
3492 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3494 args.flags = LA_SER_RUNPATH;
3495 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3498 args.flags = LA_SER_LIBPATH;
3499 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3502 args.flags = LA_SER_RUNPATH;
3503 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3506 args.flags = LA_SER_CONFIG;
3507 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3511 args.flags = LA_SER_DEFAULT;
3512 if (!obj->z_nodeflib &&
3513 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3519 rtld_dirname(const char *path, char *bname)
3523 /* Empty or NULL string gets treated as "." */
3524 if (path == NULL || *path == '\0') {
3530 /* Strip trailing slashes */
3531 endp = path + strlen(path) - 1;
3532 while (endp > path && *endp == '/')
3535 /* Find the start of the dir */
3536 while (endp > path && *endp != '/')
3539 /* Either the dir is "/" or there are no slashes */
3541 bname[0] = *endp == '/' ? '/' : '.';
3547 } while (endp > path && *endp == '/');
3550 if (endp - path + 2 > PATH_MAX)
3552 _rtld_error("Filename is too long: %s", path);
3556 strncpy(bname, path, endp - path + 1);
3557 bname[endp - path + 1] = '\0';
3562 rtld_dirname_abs(const char *path, char *base)
3566 if (realpath(path, base) == NULL)
3568 dbg("%s -> %s", path, base);
3569 last = strrchr(base, '/');
3578 linkmap_add(Obj_Entry *obj)
3580 struct link_map *l = &obj->linkmap;
3581 struct link_map *prev;
3583 obj->linkmap.l_name = obj->path;
3584 obj->linkmap.l_addr = obj->mapbase;
3585 obj->linkmap.l_ld = obj->dynamic;
3587 /* GDB needs load offset on MIPS to use the symbols */
3588 obj->linkmap.l_offs = obj->relocbase;
3591 if (r_debug.r_map == NULL) {
3597 * Scan to the end of the list, but not past the entry for the
3598 * dynamic linker, which we want to keep at the very end.
3600 for (prev = r_debug.r_map;
3601 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3602 prev = prev->l_next)
3605 /* Link in the new entry. */
3607 l->l_next = prev->l_next;
3608 if (l->l_next != NULL)
3609 l->l_next->l_prev = l;
3614 linkmap_delete(Obj_Entry *obj)
3616 struct link_map *l = &obj->linkmap;
3618 if (l->l_prev == NULL) {
3619 if ((r_debug.r_map = l->l_next) != NULL)
3620 l->l_next->l_prev = NULL;
3624 if ((l->l_prev->l_next = l->l_next) != NULL)
3625 l->l_next->l_prev = l->l_prev;
3629 * Function for the debugger to set a breakpoint on to gain control.
3631 * The two parameters allow the debugger to easily find and determine
3632 * what the runtime loader is doing and to whom it is doing it.
3634 * When the loadhook trap is hit (r_debug_state, set at program
3635 * initialization), the arguments can be found on the stack:
3637 * +8 struct link_map *m
3638 * +4 struct r_debug *rd
3642 r_debug_state(struct r_debug* rd, struct link_map *m)
3645 * The following is a hack to force the compiler to emit calls to
3646 * this function, even when optimizing. If the function is empty,
3647 * the compiler is not obliged to emit any code for calls to it,
3648 * even when marked __noinline. However, gdb depends on those
3651 __compiler_membar();
3655 * A function called after init routines have completed. This can be used to
3656 * break before a program's entry routine is called, and can be used when
3657 * main is not available in the symbol table.
3660 _r_debug_postinit(struct link_map *m)
3663 /* See r_debug_state(). */
3664 __compiler_membar();
3668 * Get address of the pointer variable in the main program.
3669 * Prefer non-weak symbol over the weak one.
3671 static const void **
3672 get_program_var_addr(const char *name, RtldLockState *lockstate)
3677 symlook_init(&req, name);
3678 req.lockstate = lockstate;
3679 donelist_init(&donelist);
3680 if (symlook_global(&req, &donelist) != 0)
3682 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3683 return ((const void **)make_function_pointer(req.sym_out,
3685 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3686 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3688 return ((const void **)(req.defobj_out->relocbase +
3689 req.sym_out->st_value));
3693 * Set a pointer variable in the main program to the given value. This
3694 * is used to set key variables such as "environ" before any of the
3695 * init functions are called.
3698 set_program_var(const char *name, const void *value)
3702 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3703 dbg("\"%s\": *%p <-- %p", name, addr, value);
3709 * Search the global objects, including dependencies and main object,
3710 * for the given symbol.
3713 symlook_global(SymLook *req, DoneList *donelist)
3716 const Objlist_Entry *elm;
3719 symlook_init_from_req(&req1, req);
3721 /* Search all objects loaded at program start up. */
3722 if (req->defobj_out == NULL ||
3723 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3724 res = symlook_list(&req1, &list_main, donelist);
3725 if (res == 0 && (req->defobj_out == NULL ||
3726 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3727 req->sym_out = req1.sym_out;
3728 req->defobj_out = req1.defobj_out;
3729 assert(req->defobj_out != NULL);
3733 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3734 STAILQ_FOREACH(elm, &list_global, link) {
3735 if (req->defobj_out != NULL &&
3736 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3738 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3739 if (res == 0 && (req->defobj_out == NULL ||
3740 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3741 req->sym_out = req1.sym_out;
3742 req->defobj_out = req1.defobj_out;
3743 assert(req->defobj_out != NULL);
3747 return (req->sym_out != NULL ? 0 : ESRCH);
3751 * Given a symbol name in a referencing object, find the corresponding
3752 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3753 * no definition was found. Returns a pointer to the Obj_Entry of the
3754 * defining object via the reference parameter DEFOBJ_OUT.
3757 symlook_default(SymLook *req, const Obj_Entry *refobj)
3760 const Objlist_Entry *elm;
3764 donelist_init(&donelist);
3765 symlook_init_from_req(&req1, req);
3767 /* Look first in the referencing object if linked symbolically. */
3768 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3769 res = symlook_obj(&req1, refobj);
3771 req->sym_out = req1.sym_out;
3772 req->defobj_out = req1.defobj_out;
3773 assert(req->defobj_out != NULL);
3777 symlook_global(req, &donelist);
3779 /* Search all dlopened DAGs containing the referencing object. */
3780 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3781 if (req->sym_out != NULL &&
3782 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3784 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3785 if (res == 0 && (req->sym_out == NULL ||
3786 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3787 req->sym_out = req1.sym_out;
3788 req->defobj_out = req1.defobj_out;
3789 assert(req->defobj_out != NULL);
3794 * Search the dynamic linker itself, and possibly resolve the
3795 * symbol from there. This is how the application links to
3796 * dynamic linker services such as dlopen.
3798 if (req->sym_out == NULL ||
3799 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3800 res = symlook_obj(&req1, &obj_rtld);
3802 req->sym_out = req1.sym_out;
3803 req->defobj_out = req1.defobj_out;
3804 assert(req->defobj_out != NULL);
3808 return (req->sym_out != NULL ? 0 : ESRCH);
3812 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3815 const Obj_Entry *defobj;
3816 const Objlist_Entry *elm;
3822 STAILQ_FOREACH(elm, objlist, link) {
3823 if (donelist_check(dlp, elm->obj))
3825 symlook_init_from_req(&req1, req);
3826 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3827 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3829 defobj = req1.defobj_out;
3830 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3837 req->defobj_out = defobj;
3844 * Search the chain of DAGS cointed to by the given Needed_Entry
3845 * for a symbol of the given name. Each DAG is scanned completely
3846 * before advancing to the next one. Returns a pointer to the symbol,
3847 * or NULL if no definition was found.
3850 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3853 const Needed_Entry *n;
3854 const Obj_Entry *defobj;
3860 symlook_init_from_req(&req1, req);
3861 for (n = needed; n != NULL; n = n->next) {
3862 if (n->obj == NULL ||
3863 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3865 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3867 defobj = req1.defobj_out;
3868 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3874 req->defobj_out = defobj;
3881 * Search the symbol table of a single shared object for a symbol of
3882 * the given name and version, if requested. Returns a pointer to the
3883 * symbol, or NULL if no definition was found. If the object is
3884 * filter, return filtered symbol from filtee.
3886 * The symbol's hash value is passed in for efficiency reasons; that
3887 * eliminates many recomputations of the hash value.
3890 symlook_obj(SymLook *req, const Obj_Entry *obj)
3894 int flags, res, mres;
3897 * If there is at least one valid hash at this point, we prefer to
3898 * use the faster GNU version if available.
3900 if (obj->valid_hash_gnu)
3901 mres = symlook_obj1_gnu(req, obj);
3902 else if (obj->valid_hash_sysv)
3903 mres = symlook_obj1_sysv(req, obj);
3908 if (obj->needed_filtees != NULL) {
3909 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3910 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3911 donelist_init(&donelist);
3912 symlook_init_from_req(&req1, req);
3913 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3915 req->sym_out = req1.sym_out;
3916 req->defobj_out = req1.defobj_out;
3920 if (obj->needed_aux_filtees != NULL) {
3921 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3922 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3923 donelist_init(&donelist);
3924 symlook_init_from_req(&req1, req);
3925 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3927 req->sym_out = req1.sym_out;
3928 req->defobj_out = req1.defobj_out;
3936 /* Symbol match routine common to both hash functions */
3938 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3939 const unsigned long symnum)
3942 const Elf_Sym *symp;
3945 symp = obj->symtab + symnum;
3946 strp = obj->strtab + symp->st_name;
3948 switch (ELF_ST_TYPE(symp->st_info)) {
3954 if (symp->st_value == 0)
3958 if (symp->st_shndx != SHN_UNDEF)
3961 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3962 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3969 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3972 if (req->ventry == NULL) {
3973 if (obj->versyms != NULL) {
3974 verndx = VER_NDX(obj->versyms[symnum]);
3975 if (verndx > obj->vernum) {
3977 "%s: symbol %s references wrong version %d",
3978 obj->path, obj->strtab + symnum, verndx);
3982 * If we are not called from dlsym (i.e. this
3983 * is a normal relocation from unversioned
3984 * binary), accept the symbol immediately if
3985 * it happens to have first version after this
3986 * shared object became versioned. Otherwise,
3987 * if symbol is versioned and not hidden,
3988 * remember it. If it is the only symbol with
3989 * this name exported by the shared object, it
3990 * will be returned as a match by the calling
3991 * function. If symbol is global (verndx < 2)
3992 * accept it unconditionally.
3994 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3995 verndx == VER_NDX_GIVEN) {
3996 result->sym_out = symp;
3999 else if (verndx >= VER_NDX_GIVEN) {
4000 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4002 if (result->vsymp == NULL)
4003 result->vsymp = symp;
4009 result->sym_out = symp;
4012 if (obj->versyms == NULL) {
4013 if (object_match_name(obj, req->ventry->name)) {
4014 _rtld_error("%s: object %s should provide version %s "
4015 "for symbol %s", obj_rtld.path, obj->path,
4016 req->ventry->name, obj->strtab + symnum);
4020 verndx = VER_NDX(obj->versyms[symnum]);
4021 if (verndx > obj->vernum) {
4022 _rtld_error("%s: symbol %s references wrong version %d",
4023 obj->path, obj->strtab + symnum, verndx);
4026 if (obj->vertab[verndx].hash != req->ventry->hash ||
4027 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4029 * Version does not match. Look if this is a
4030 * global symbol and if it is not hidden. If
4031 * global symbol (verndx < 2) is available,
4032 * use it. Do not return symbol if we are
4033 * called by dlvsym, because dlvsym looks for
4034 * a specific version and default one is not
4035 * what dlvsym wants.
4037 if ((req->flags & SYMLOOK_DLSYM) ||
4038 (verndx >= VER_NDX_GIVEN) ||
4039 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4043 result->sym_out = symp;
4048 * Search for symbol using SysV hash function.
4049 * obj->buckets is known not to be NULL at this point; the test for this was
4050 * performed with the obj->valid_hash_sysv assignment.
4053 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4055 unsigned long symnum;
4056 Sym_Match_Result matchres;
4058 matchres.sym_out = NULL;
4059 matchres.vsymp = NULL;
4060 matchres.vcount = 0;
4062 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4063 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4064 if (symnum >= obj->nchains)
4065 return (ESRCH); /* Bad object */
4067 if (matched_symbol(req, obj, &matchres, symnum)) {
4068 req->sym_out = matchres.sym_out;
4069 req->defobj_out = obj;
4073 if (matchres.vcount == 1) {
4074 req->sym_out = matchres.vsymp;
4075 req->defobj_out = obj;
4081 /* Search for symbol using GNU hash function */
4083 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4085 Elf_Addr bloom_word;
4086 const Elf32_Word *hashval;
4088 Sym_Match_Result matchres;
4089 unsigned int h1, h2;
4090 unsigned long symnum;
4092 matchres.sym_out = NULL;
4093 matchres.vsymp = NULL;
4094 matchres.vcount = 0;
4096 /* Pick right bitmask word from Bloom filter array */
4097 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4098 obj->maskwords_bm_gnu];
4100 /* Calculate modulus word size of gnu hash and its derivative */
4101 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4102 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4104 /* Filter out the "definitely not in set" queries */
4105 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4108 /* Locate hash chain and corresponding value element*/
4109 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4112 hashval = &obj->chain_zero_gnu[bucket];
4114 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4115 symnum = hashval - obj->chain_zero_gnu;
4116 if (matched_symbol(req, obj, &matchres, symnum)) {
4117 req->sym_out = matchres.sym_out;
4118 req->defobj_out = obj;
4122 } while ((*hashval++ & 1) == 0);
4123 if (matchres.vcount == 1) {
4124 req->sym_out = matchres.vsymp;
4125 req->defobj_out = obj;
4132 trace_loaded_objects(Obj_Entry *obj)
4134 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4137 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4140 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4141 fmt1 = "\t%o => %p (%x)\n";
4143 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4144 fmt2 = "\t%o (%x)\n";
4146 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4148 for (; obj; obj = obj->next) {
4149 Needed_Entry *needed;
4153 if (list_containers && obj->needed != NULL)
4154 rtld_printf("%s:\n", obj->path);
4155 for (needed = obj->needed; needed; needed = needed->next) {
4156 if (needed->obj != NULL) {
4157 if (needed->obj->traced && !list_containers)
4159 needed->obj->traced = true;
4160 path = needed->obj->path;
4164 name = (char *)obj->strtab + needed->name;
4165 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4167 fmt = is_lib ? fmt1 : fmt2;
4168 while ((c = *fmt++) != '\0') {
4194 rtld_putstr(main_local);
4197 rtld_putstr(obj_main->path);
4204 rtld_printf("%d", sodp->sod_major);
4207 rtld_printf("%d", sodp->sod_minor);
4214 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4227 * Unload a dlopened object and its dependencies from memory and from
4228 * our data structures. It is assumed that the DAG rooted in the
4229 * object has already been unreferenced, and that the object has a
4230 * reference count of 0.
4233 unload_object(Obj_Entry *root)
4238 assert(root->refcount == 0);
4241 * Pass over the DAG removing unreferenced objects from
4242 * appropriate lists.
4244 unlink_object(root);
4246 /* Unmap all objects that are no longer referenced. */
4247 linkp = &obj_list->next;
4248 while ((obj = *linkp) != NULL) {
4249 if (obj->refcount == 0) {
4250 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4252 dbg("unloading \"%s\"", obj->path);
4253 unload_filtees(root);
4254 munmap(obj->mapbase, obj->mapsize);
4255 linkmap_delete(obj);
4266 unlink_object(Obj_Entry *root)
4270 if (root->refcount == 0) {
4271 /* Remove the object from the RTLD_GLOBAL list. */
4272 objlist_remove(&list_global, root);
4274 /* Remove the object from all objects' DAG lists. */
4275 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4276 objlist_remove(&elm->obj->dldags, root);
4277 if (elm->obj != root)
4278 unlink_object(elm->obj);
4284 ref_dag(Obj_Entry *root)
4288 assert(root->dag_inited);
4289 STAILQ_FOREACH(elm, &root->dagmembers, link)
4290 elm->obj->refcount++;
4294 unref_dag(Obj_Entry *root)
4298 assert(root->dag_inited);
4299 STAILQ_FOREACH(elm, &root->dagmembers, link)
4300 elm->obj->refcount--;
4304 * Common code for MD __tls_get_addr().
4306 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4308 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4310 Elf_Addr *newdtv, *dtv;
4311 RtldLockState lockstate;
4315 /* Check dtv generation in case new modules have arrived */
4316 if (dtv[0] != tls_dtv_generation) {
4317 wlock_acquire(rtld_bind_lock, &lockstate);
4318 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4320 if (to_copy > tls_max_index)
4321 to_copy = tls_max_index;
4322 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4323 newdtv[0] = tls_dtv_generation;
4324 newdtv[1] = tls_max_index;
4326 lock_release(rtld_bind_lock, &lockstate);
4327 dtv = *dtvp = newdtv;
4330 /* Dynamically allocate module TLS if necessary */
4331 if (dtv[index + 1] == 0) {
4332 /* Signal safe, wlock will block out signals. */
4333 wlock_acquire(rtld_bind_lock, &lockstate);
4334 if (!dtv[index + 1])
4335 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4336 lock_release(rtld_bind_lock, &lockstate);
4338 return ((void *)(dtv[index + 1] + offset));
4342 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4347 /* Check dtv generation in case new modules have arrived */
4348 if (__predict_true(dtv[0] == tls_dtv_generation &&
4349 dtv[index + 1] != 0))
4350 return ((void *)(dtv[index + 1] + offset));
4351 return (tls_get_addr_slow(dtvp, index, offset));
4354 #if defined(__arm__) || defined(__mips__) || defined(__powerpc__)
4357 * Allocate Static TLS using the Variant I method.
4360 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4369 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4372 assert(tcbsize >= TLS_TCB_SIZE);
4373 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4374 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4376 if (oldtcb != NULL) {
4377 memcpy(tls, oldtcb, tls_static_space);
4380 /* Adjust the DTV. */
4382 for (i = 0; i < dtv[1]; i++) {
4383 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4384 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4385 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4389 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4391 dtv[0] = tls_dtv_generation;
4392 dtv[1] = tls_max_index;
4394 for (obj = objs; obj; obj = obj->next) {
4395 if (obj->tlsoffset > 0) {
4396 addr = (Elf_Addr)tls + obj->tlsoffset;
4397 if (obj->tlsinitsize > 0)
4398 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4399 if (obj->tlssize > obj->tlsinitsize)
4400 memset((void*) (addr + obj->tlsinitsize), 0,
4401 obj->tlssize - obj->tlsinitsize);
4402 dtv[obj->tlsindex + 1] = addr;
4411 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4414 Elf_Addr tlsstart, tlsend;
4417 assert(tcbsize >= TLS_TCB_SIZE);
4419 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4420 tlsend = tlsstart + tls_static_space;
4422 dtv = *(Elf_Addr **)tlsstart;
4424 for (i = 0; i < dtvsize; i++) {
4425 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4426 free((void*)dtv[i+2]);
4435 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4438 * Allocate Static TLS using the Variant II method.
4441 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4444 size_t size, ralign;
4446 Elf_Addr *dtv, *olddtv;
4447 Elf_Addr segbase, oldsegbase, addr;
4451 if (tls_static_max_align > ralign)
4452 ralign = tls_static_max_align;
4453 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4455 assert(tcbsize >= 2*sizeof(Elf_Addr));
4456 tls = malloc_aligned(size, ralign);
4457 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4459 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4460 ((Elf_Addr*)segbase)[0] = segbase;
4461 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4463 dtv[0] = tls_dtv_generation;
4464 dtv[1] = tls_max_index;
4468 * Copy the static TLS block over whole.
4470 oldsegbase = (Elf_Addr) oldtls;
4471 memcpy((void *)(segbase - tls_static_space),
4472 (const void *)(oldsegbase - tls_static_space),
4476 * If any dynamic TLS blocks have been created tls_get_addr(),
4479 olddtv = ((Elf_Addr**)oldsegbase)[1];
4480 for (i = 0; i < olddtv[1]; i++) {
4481 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4482 dtv[i+2] = olddtv[i+2];
4488 * We assume that this block was the one we created with
4489 * allocate_initial_tls().
4491 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4493 for (obj = objs; obj; obj = obj->next) {
4494 if (obj->tlsoffset) {
4495 addr = segbase - obj->tlsoffset;
4496 memset((void*) (addr + obj->tlsinitsize),
4497 0, obj->tlssize - obj->tlsinitsize);
4499 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4500 dtv[obj->tlsindex + 1] = addr;
4505 return (void*) segbase;
4509 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4512 size_t size, ralign;
4514 Elf_Addr tlsstart, tlsend;
4517 * Figure out the size of the initial TLS block so that we can
4518 * find stuff which ___tls_get_addr() allocated dynamically.
4521 if (tls_static_max_align > ralign)
4522 ralign = tls_static_max_align;
4523 size = round(tls_static_space, ralign);
4525 dtv = ((Elf_Addr**)tls)[1];
4527 tlsend = (Elf_Addr) tls;
4528 tlsstart = tlsend - size;
4529 for (i = 0; i < dtvsize; i++) {
4530 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4531 free_aligned((void *)dtv[i + 2]);
4535 free_aligned((void *)tlsstart);
4542 * Allocate TLS block for module with given index.
4545 allocate_module_tls(int index)
4550 for (obj = obj_list; obj; obj = obj->next) {
4551 if (obj->tlsindex == index)
4555 _rtld_error("Can't find module with TLS index %d", index);
4559 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4560 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4561 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4567 allocate_tls_offset(Obj_Entry *obj)
4574 if (obj->tlssize == 0) {
4575 obj->tls_done = true;
4579 if (obj->tlsindex == 1)
4580 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4582 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4583 obj->tlssize, obj->tlsalign);
4586 * If we have already fixed the size of the static TLS block, we
4587 * must stay within that size. When allocating the static TLS, we
4588 * leave a small amount of space spare to be used for dynamically
4589 * loading modules which use static TLS.
4591 if (tls_static_space != 0) {
4592 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4594 } else if (obj->tlsalign > tls_static_max_align) {
4595 tls_static_max_align = obj->tlsalign;
4598 tls_last_offset = obj->tlsoffset = off;
4599 tls_last_size = obj->tlssize;
4600 obj->tls_done = true;
4606 free_tls_offset(Obj_Entry *obj)
4610 * If we were the last thing to allocate out of the static TLS
4611 * block, we give our space back to the 'allocator'. This is a
4612 * simplistic workaround to allow libGL.so.1 to be loaded and
4613 * unloaded multiple times.
4615 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4616 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4617 tls_last_offset -= obj->tlssize;
4623 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4626 RtldLockState lockstate;
4628 wlock_acquire(rtld_bind_lock, &lockstate);
4629 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4630 lock_release(rtld_bind_lock, &lockstate);
4635 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4637 RtldLockState lockstate;
4639 wlock_acquire(rtld_bind_lock, &lockstate);
4640 free_tls(tcb, tcbsize, tcbalign);
4641 lock_release(rtld_bind_lock, &lockstate);
4645 object_add_name(Obj_Entry *obj, const char *name)
4651 entry = malloc(sizeof(Name_Entry) + len);
4653 if (entry != NULL) {
4654 strcpy(entry->name, name);
4655 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4660 object_match_name(const Obj_Entry *obj, const char *name)
4664 STAILQ_FOREACH(entry, &obj->names, link) {
4665 if (strcmp(name, entry->name) == 0)
4672 locate_dependency(const Obj_Entry *obj, const char *name)
4674 const Objlist_Entry *entry;
4675 const Needed_Entry *needed;
4677 STAILQ_FOREACH(entry, &list_main, link) {
4678 if (object_match_name(entry->obj, name))
4682 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4683 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4684 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4686 * If there is DT_NEEDED for the name we are looking for,
4687 * we are all set. Note that object might not be found if
4688 * dependency was not loaded yet, so the function can
4689 * return NULL here. This is expected and handled
4690 * properly by the caller.
4692 return (needed->obj);
4695 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4701 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4702 const Elf_Vernaux *vna)
4704 const Elf_Verdef *vd;
4705 const char *vername;
4707 vername = refobj->strtab + vna->vna_name;
4708 vd = depobj->verdef;
4710 _rtld_error("%s: version %s required by %s not defined",
4711 depobj->path, vername, refobj->path);
4715 if (vd->vd_version != VER_DEF_CURRENT) {
4716 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4717 depobj->path, vd->vd_version);
4720 if (vna->vna_hash == vd->vd_hash) {
4721 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4722 ((char *)vd + vd->vd_aux);
4723 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4726 if (vd->vd_next == 0)
4728 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4730 if (vna->vna_flags & VER_FLG_WEAK)
4732 _rtld_error("%s: version %s required by %s not found",
4733 depobj->path, vername, refobj->path);
4738 rtld_verify_object_versions(Obj_Entry *obj)
4740 const Elf_Verneed *vn;
4741 const Elf_Verdef *vd;
4742 const Elf_Verdaux *vda;
4743 const Elf_Vernaux *vna;
4744 const Obj_Entry *depobj;
4745 int maxvernum, vernum;
4747 if (obj->ver_checked)
4749 obj->ver_checked = true;
4753 * Walk over defined and required version records and figure out
4754 * max index used by any of them. Do very basic sanity checking
4758 while (vn != NULL) {
4759 if (vn->vn_version != VER_NEED_CURRENT) {
4760 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4761 obj->path, vn->vn_version);
4764 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4766 vernum = VER_NEED_IDX(vna->vna_other);
4767 if (vernum > maxvernum)
4769 if (vna->vna_next == 0)
4771 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4773 if (vn->vn_next == 0)
4775 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4779 while (vd != NULL) {
4780 if (vd->vd_version != VER_DEF_CURRENT) {
4781 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4782 obj->path, vd->vd_version);
4785 vernum = VER_DEF_IDX(vd->vd_ndx);
4786 if (vernum > maxvernum)
4788 if (vd->vd_next == 0)
4790 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4797 * Store version information in array indexable by version index.
4798 * Verify that object version requirements are satisfied along the
4801 obj->vernum = maxvernum + 1;
4802 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4805 while (vd != NULL) {
4806 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4807 vernum = VER_DEF_IDX(vd->vd_ndx);
4808 assert(vernum <= maxvernum);
4809 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4810 obj->vertab[vernum].hash = vd->vd_hash;
4811 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4812 obj->vertab[vernum].file = NULL;
4813 obj->vertab[vernum].flags = 0;
4815 if (vd->vd_next == 0)
4817 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4821 while (vn != NULL) {
4822 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4825 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4827 if (check_object_provided_version(obj, depobj, vna))
4829 vernum = VER_NEED_IDX(vna->vna_other);
4830 assert(vernum <= maxvernum);
4831 obj->vertab[vernum].hash = vna->vna_hash;
4832 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4833 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4834 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4835 VER_INFO_HIDDEN : 0;
4836 if (vna->vna_next == 0)
4838 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4840 if (vn->vn_next == 0)
4842 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4848 rtld_verify_versions(const Objlist *objlist)
4850 Objlist_Entry *entry;
4854 STAILQ_FOREACH(entry, objlist, link) {
4856 * Skip dummy objects or objects that have their version requirements
4859 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4861 if (rtld_verify_object_versions(entry->obj) == -1) {
4863 if (ld_tracing == NULL)
4867 if (rc == 0 || ld_tracing != NULL)
4868 rc = rtld_verify_object_versions(&obj_rtld);
4873 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4878 vernum = VER_NDX(obj->versyms[symnum]);
4879 if (vernum >= obj->vernum) {
4880 _rtld_error("%s: symbol %s has wrong verneed value %d",
4881 obj->path, obj->strtab + symnum, vernum);
4882 } else if (obj->vertab[vernum].hash != 0) {
4883 return &obj->vertab[vernum];
4890 _rtld_get_stack_prot(void)
4893 return (stack_prot);
4897 _rtld_is_dlopened(void *arg)
4900 RtldLockState lockstate;
4903 rlock_acquire(rtld_bind_lock, &lockstate);
4906 obj = obj_from_addr(arg);
4908 _rtld_error("No shared object contains address");
4909 lock_release(rtld_bind_lock, &lockstate);
4912 res = obj->dlopened ? 1 : 0;
4913 lock_release(rtld_bind_lock, &lockstate);
4918 map_stacks_exec(RtldLockState *lockstate)
4920 void (*thr_map_stacks_exec)(void);
4922 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4924 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4925 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4926 if (thr_map_stacks_exec != NULL) {
4927 stack_prot |= PROT_EXEC;
4928 thr_map_stacks_exec();
4933 symlook_init(SymLook *dst, const char *name)
4936 bzero(dst, sizeof(*dst));
4938 dst->hash = elf_hash(name);
4939 dst->hash_gnu = gnu_hash(name);
4943 symlook_init_from_req(SymLook *dst, const SymLook *src)
4946 dst->name = src->name;
4947 dst->hash = src->hash;
4948 dst->hash_gnu = src->hash_gnu;
4949 dst->ventry = src->ventry;
4950 dst->flags = src->flags;
4951 dst->defobj_out = NULL;
4952 dst->sym_out = NULL;
4953 dst->lockstate = src->lockstate;
4958 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
4961 parse_libdir(const char *str)
4963 static const int RADIX = 10; /* XXXJA: possibly support hex? */
4970 for (c = *str; c != '\0'; c = *++str) {
4971 if (c < '0' || c > '9')
4978 /* Make sure we actually parsed something. */
4980 _rtld_error("failed to parse directory FD from '%s'", str);
4987 * Overrides for libc_pic-provided functions.
4991 __getosreldate(void)
5001 oid[1] = KERN_OSRELDATE;
5003 len = sizeof(osrel);
5004 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5005 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5017 void (*__cleanup)(void);
5018 int __isthreaded = 0;
5019 int _thread_autoinit_dummy_decl = 1;
5022 * No unresolved symbols for rtld.
5025 __pthread_cxa_finalize(struct dl_phdr_info *a)
5030 __stack_chk_fail(void)
5033 _rtld_error("stack overflow detected; terminated");
5036 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5042 _rtld_error("buffer overflow detected; terminated");
5047 rtld_strerror(int errnum)
5050 if (errnum < 0 || errnum >= sys_nerr)
5051 return ("Unknown error");
5052 return (sys_errlist[errnum]);