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;
880 int plttype = DT_REL;
886 obj->bind_now = false;
887 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
888 switch (dynp->d_tag) {
891 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
895 obj->relsize = dynp->d_un.d_val;
899 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
903 obj->pltrel = (const Elf_Rel *)
904 (obj->relocbase + dynp->d_un.d_ptr);
908 obj->pltrelsize = dynp->d_un.d_val;
912 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
916 obj->relasize = dynp->d_un.d_val;
920 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
924 plttype = dynp->d_un.d_val;
925 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
929 obj->symtab = (const Elf_Sym *)
930 (obj->relocbase + dynp->d_un.d_ptr);
934 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
938 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
942 obj->strsize = dynp->d_un.d_val;
946 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
951 obj->verneednum = dynp->d_un.d_val;
955 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
960 obj->verdefnum = dynp->d_un.d_val;
964 obj->versyms = (const Elf_Versym *)(obj->relocbase +
970 hashtab = (const Elf_Hashelt *)(obj->relocbase +
972 obj->nbuckets = hashtab[0];
973 obj->nchains = hashtab[1];
974 obj->buckets = hashtab + 2;
975 obj->chains = obj->buckets + obj->nbuckets;
976 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
977 obj->buckets != NULL;
983 hashtab = (const Elf_Hashelt *)(obj->relocbase +
985 obj->nbuckets_gnu = hashtab[0];
986 obj->symndx_gnu = hashtab[1];
987 nmaskwords = hashtab[2];
988 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
989 /* Number of bitmask words is required to be power of 2 */
990 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
991 obj->maskwords_bm_gnu = nmaskwords - 1;
992 obj->shift2_gnu = hashtab[3];
993 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
994 obj->buckets_gnu = hashtab + 4 + bloom_size32;
995 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
997 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
998 obj->buckets_gnu != NULL;
1004 Needed_Entry *nep = NEW(Needed_Entry);
1005 nep->name = dynp->d_un.d_val;
1010 needed_tail = &nep->next;
1016 Needed_Entry *nep = NEW(Needed_Entry);
1017 nep->name = dynp->d_un.d_val;
1021 *needed_filtees_tail = nep;
1022 needed_filtees_tail = &nep->next;
1028 Needed_Entry *nep = NEW(Needed_Entry);
1029 nep->name = dynp->d_un.d_val;
1033 *needed_aux_filtees_tail = nep;
1034 needed_aux_filtees_tail = &nep->next;
1039 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1043 obj->textrel = true;
1047 obj->symbolic = true;
1052 * We have to wait until later to process this, because we
1053 * might not have gotten the address of the string table yet.
1063 *dyn_runpath = dynp;
1067 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1070 case DT_PREINIT_ARRAY:
1071 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1074 case DT_PREINIT_ARRAYSZ:
1075 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1079 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1082 case DT_INIT_ARRAYSZ:
1083 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1087 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1091 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1094 case DT_FINI_ARRAYSZ:
1095 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1099 * Don't process DT_DEBUG on MIPS as the dynamic section
1100 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1105 /* XXX - not implemented yet */
1107 dbg("Filling in DT_DEBUG entry");
1108 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1113 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1114 obj->z_origin = true;
1115 if (dynp->d_un.d_val & DF_SYMBOLIC)
1116 obj->symbolic = true;
1117 if (dynp->d_un.d_val & DF_TEXTREL)
1118 obj->textrel = true;
1119 if (dynp->d_un.d_val & DF_BIND_NOW)
1120 obj->bind_now = true;
1121 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1125 case DT_MIPS_LOCAL_GOTNO:
1126 obj->local_gotno = dynp->d_un.d_val;
1129 case DT_MIPS_SYMTABNO:
1130 obj->symtabno = dynp->d_un.d_val;
1133 case DT_MIPS_GOTSYM:
1134 obj->gotsym = dynp->d_un.d_val;
1137 case DT_MIPS_RLD_MAP:
1138 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1143 if (dynp->d_un.d_val & DF_1_NOOPEN)
1144 obj->z_noopen = true;
1145 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1146 obj->z_origin = true;
1147 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1149 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1150 obj->bind_now = true;
1151 if (dynp->d_un.d_val & DF_1_NODELETE)
1152 obj->z_nodelete = true;
1153 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1154 obj->z_loadfltr = true;
1155 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1156 obj->z_interpose = true;
1157 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1158 obj->z_nodeflib = true;
1163 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1170 obj->traced = false;
1172 if (plttype == DT_RELA) {
1173 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1175 obj->pltrelasize = obj->pltrelsize;
1176 obj->pltrelsize = 0;
1179 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1180 if (obj->valid_hash_sysv)
1181 obj->dynsymcount = obj->nchains;
1182 else if (obj->valid_hash_gnu) {
1183 obj->dynsymcount = 0;
1184 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1185 if (obj->buckets_gnu[bkt] == 0)
1187 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1190 while ((*hashval++ & 1u) == 0);
1192 obj->dynsymcount += obj->symndx_gnu;
1197 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1198 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1201 if (obj->z_origin && obj->origin_path == NULL) {
1202 obj->origin_path = xmalloc(PATH_MAX);
1203 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1207 if (dyn_runpath != NULL) {
1208 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1210 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1212 else if (dyn_rpath != NULL) {
1213 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1215 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1218 if (dyn_soname != NULL)
1219 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1223 digest_dynamic(Obj_Entry *obj, int early)
1225 const Elf_Dyn *dyn_rpath;
1226 const Elf_Dyn *dyn_soname;
1227 const Elf_Dyn *dyn_runpath;
1229 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1230 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1234 * Process a shared object's program header. This is used only for the
1235 * main program, when the kernel has already loaded the main program
1236 * into memory before calling the dynamic linker. It creates and
1237 * returns an Obj_Entry structure.
1240 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1243 const Elf_Phdr *phlimit = phdr + phnum;
1245 Elf_Addr note_start, note_end;
1249 for (ph = phdr; ph < phlimit; ph++) {
1250 if (ph->p_type != PT_PHDR)
1254 obj->phsize = ph->p_memsz;
1255 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1259 obj->stack_flags = PF_X | PF_R | PF_W;
1261 for (ph = phdr; ph < phlimit; ph++) {
1262 switch (ph->p_type) {
1265 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1269 if (nsegs == 0) { /* First load segment */
1270 obj->vaddrbase = trunc_page(ph->p_vaddr);
1271 obj->mapbase = obj->vaddrbase + obj->relocbase;
1272 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1274 } else { /* Last load segment */
1275 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1282 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1287 obj->tlssize = ph->p_memsz;
1288 obj->tlsalign = ph->p_align;
1289 obj->tlsinitsize = ph->p_filesz;
1290 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1294 obj->stack_flags = ph->p_flags;
1298 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1299 obj->relro_size = round_page(ph->p_memsz);
1303 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1304 note_end = note_start + ph->p_filesz;
1305 digest_notes(obj, note_start, note_end);
1310 _rtld_error("%s: too few PT_LOAD segments", path);
1319 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1321 const Elf_Note *note;
1322 const char *note_name;
1325 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1326 note = (const Elf_Note *)((const char *)(note + 1) +
1327 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1328 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1329 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1330 note->n_descsz != sizeof(int32_t))
1332 if (note->n_type != ABI_NOTETYPE &&
1333 note->n_type != CRT_NOINIT_NOTETYPE)
1335 note_name = (const char *)(note + 1);
1336 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1337 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1339 switch (note->n_type) {
1341 /* FreeBSD osrel note */
1342 p = (uintptr_t)(note + 1);
1343 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1344 obj->osrel = *(const int32_t *)(p);
1345 dbg("note osrel %d", obj->osrel);
1347 case CRT_NOINIT_NOTETYPE:
1348 /* FreeBSD 'crt does not call init' note */
1349 obj->crt_no_init = true;
1350 dbg("note crt_no_init");
1357 dlcheck(void *handle)
1361 for (obj = obj_list; obj != NULL; obj = obj->next)
1362 if (obj == (Obj_Entry *) handle)
1365 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1366 _rtld_error("Invalid shared object handle %p", handle);
1373 * If the given object is already in the donelist, return true. Otherwise
1374 * add the object to the list and return false.
1377 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1381 for (i = 0; i < dlp->num_used; i++)
1382 if (dlp->objs[i] == obj)
1385 * Our donelist allocation should always be sufficient. But if
1386 * our threads locking isn't working properly, more shared objects
1387 * could have been loaded since we allocated the list. That should
1388 * never happen, but we'll handle it properly just in case it does.
1390 if (dlp->num_used < dlp->num_alloc)
1391 dlp->objs[dlp->num_used++] = obj;
1396 * Hash function for symbol table lookup. Don't even think about changing
1397 * this. It is specified by the System V ABI.
1400 elf_hash(const char *name)
1402 const unsigned char *p = (const unsigned char *) name;
1403 unsigned long h = 0;
1406 while (*p != '\0') {
1407 h = (h << 4) + *p++;
1408 if ((g = h & 0xf0000000) != 0)
1416 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1417 * unsigned in case it's implemented with a wider type.
1420 gnu_hash(const char *s)
1426 for (c = *s; c != '\0'; c = *++s)
1428 return (h & 0xffffffff);
1433 * Find the library with the given name, and return its full pathname.
1434 * The returned string is dynamically allocated. Generates an error
1435 * message and returns NULL if the library cannot be found.
1437 * If the second argument is non-NULL, then it refers to an already-
1438 * loaded shared object, whose library search path will be searched.
1440 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1441 * descriptor (which is close-on-exec) will be passed out via the third
1444 * The search order is:
1445 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1446 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1448 * DT_RUNPATH in the referencing file
1449 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1451 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1453 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1456 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1460 bool nodeflib, objgiven;
1462 objgiven = refobj != NULL;
1463 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1464 if (xname[0] != '/' && !trust) {
1465 _rtld_error("Absolute pathname required for shared object \"%s\"",
1469 if (objgiven && refobj->z_origin) {
1470 return (origin_subst(__DECONST(char *, xname),
1471 refobj->origin_path));
1473 return (xstrdup(xname));
1477 if (libmap_disable || !objgiven ||
1478 (name = lm_find(refobj->path, xname)) == NULL)
1479 name = (char *)xname;
1481 dbg(" Searching for \"%s\"", name);
1484 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1485 * back to pre-conforming behaviour if user requested so with
1486 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1489 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1490 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1492 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1493 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1494 (pathname = search_library_path(name, gethints(false))) != NULL ||
1495 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1498 nodeflib = objgiven ? refobj->z_nodeflib : false;
1500 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1501 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1502 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1503 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1505 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1506 (pathname = search_library_pathfds(name, ld_library_dirs, fdp)) != NULL ||
1507 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1508 (objgiven && !nodeflib &&
1509 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1513 if (objgiven && refobj->path != NULL) {
1514 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1515 name, basename(refobj->path));
1517 _rtld_error("Shared object \"%s\" not found", name);
1523 * Given a symbol number in a referencing object, find the corresponding
1524 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1525 * no definition was found. Returns a pointer to the Obj_Entry of the
1526 * defining object via the reference parameter DEFOBJ_OUT.
1529 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1530 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1531 RtldLockState *lockstate)
1535 const Obj_Entry *defobj;
1541 * If we have already found this symbol, get the information from
1544 if (symnum >= refobj->dynsymcount)
1545 return NULL; /* Bad object */
1546 if (cache != NULL && cache[symnum].sym != NULL) {
1547 *defobj_out = cache[symnum].obj;
1548 return cache[symnum].sym;
1551 ref = refobj->symtab + symnum;
1552 name = refobj->strtab + ref->st_name;
1557 * We don't have to do a full scale lookup if the symbol is local.
1558 * We know it will bind to the instance in this load module; to
1559 * which we already have a pointer (ie ref). By not doing a lookup,
1560 * we not only improve performance, but it also avoids unresolvable
1561 * symbols when local symbols are not in the hash table. This has
1562 * been seen with the ia64 toolchain.
1564 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1565 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1566 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1569 symlook_init(&req, name);
1571 req.ventry = fetch_ventry(refobj, symnum);
1572 req.lockstate = lockstate;
1573 res = symlook_default(&req, refobj);
1576 defobj = req.defobj_out;
1584 * If we found no definition and the reference is weak, treat the
1585 * symbol as having the value zero.
1587 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1593 *defobj_out = defobj;
1594 /* Record the information in the cache to avoid subsequent lookups. */
1595 if (cache != NULL) {
1596 cache[symnum].sym = def;
1597 cache[symnum].obj = defobj;
1600 if (refobj != &obj_rtld)
1601 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1607 * Return the search path from the ldconfig hints file, reading it if
1608 * necessary. If nostdlib is true, then the default search paths are
1609 * not added to result.
1611 * Returns NULL if there are problems with the hints file,
1612 * or if the search path there is empty.
1615 gethints(bool nostdlib)
1617 static char *hints, *filtered_path;
1618 struct elfhints_hdr hdr;
1619 struct fill_search_info_args sargs, hargs;
1620 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1621 struct dl_serpath *SLPpath, *hintpath;
1623 unsigned int SLPndx, hintndx, fndx, fcount;
1628 /* First call, read the hints file */
1629 if (hints == NULL) {
1630 /* Keep from trying again in case the hints file is bad. */
1633 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1635 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1636 hdr.magic != ELFHINTS_MAGIC ||
1641 p = xmalloc(hdr.dirlistlen + 1);
1642 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1643 read(fd, p, hdr.dirlistlen + 1) !=
1644 (ssize_t)hdr.dirlistlen + 1) {
1654 * If caller agreed to receive list which includes the default
1655 * paths, we are done. Otherwise, if we still did not
1656 * calculated filtered result, do it now.
1659 return (hints[0] != '\0' ? hints : NULL);
1660 if (filtered_path != NULL)
1664 * Obtain the list of all configured search paths, and the
1665 * list of the default paths.
1667 * First estimate the size of the results.
1669 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1671 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1674 sargs.request = RTLD_DI_SERINFOSIZE;
1675 sargs.serinfo = &smeta;
1676 hargs.request = RTLD_DI_SERINFOSIZE;
1677 hargs.serinfo = &hmeta;
1679 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1680 path_enumerate(p, fill_search_info, &hargs);
1682 SLPinfo = xmalloc(smeta.dls_size);
1683 hintinfo = xmalloc(hmeta.dls_size);
1686 * Next fetch both sets of paths.
1688 sargs.request = RTLD_DI_SERINFO;
1689 sargs.serinfo = SLPinfo;
1690 sargs.serpath = &SLPinfo->dls_serpath[0];
1691 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1693 hargs.request = RTLD_DI_SERINFO;
1694 hargs.serinfo = hintinfo;
1695 hargs.serpath = &hintinfo->dls_serpath[0];
1696 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1698 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1699 path_enumerate(p, fill_search_info, &hargs);
1702 * Now calculate the difference between two sets, by excluding
1703 * standard paths from the full set.
1707 filtered_path = xmalloc(hdr.dirlistlen + 1);
1708 hintpath = &hintinfo->dls_serpath[0];
1709 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1711 SLPpath = &SLPinfo->dls_serpath[0];
1713 * Check each standard path against current.
1715 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1716 /* matched, skip the path */
1717 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1725 * Not matched against any standard path, add the path
1726 * to result. Separate consequtive paths with ':'.
1729 filtered_path[fndx] = ':';
1733 flen = strlen(hintpath->dls_name);
1734 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1737 filtered_path[fndx] = '\0';
1743 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1747 init_dag(Obj_Entry *root)
1749 const Needed_Entry *needed;
1750 const Objlist_Entry *elm;
1753 if (root->dag_inited)
1755 donelist_init(&donelist);
1757 /* Root object belongs to own DAG. */
1758 objlist_push_tail(&root->dldags, root);
1759 objlist_push_tail(&root->dagmembers, root);
1760 donelist_check(&donelist, root);
1763 * Add dependencies of root object to DAG in breadth order
1764 * by exploiting the fact that each new object get added
1765 * to the tail of the dagmembers list.
1767 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1768 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1769 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1771 objlist_push_tail(&needed->obj->dldags, root);
1772 objlist_push_tail(&root->dagmembers, needed->obj);
1775 root->dag_inited = true;
1779 process_nodelete(Obj_Entry *root)
1781 const Objlist_Entry *elm;
1784 * Walk over object DAG and process every dependent object that
1785 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1786 * which then should have its reference upped separately.
1788 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1789 if (elm->obj != NULL && elm->obj->z_nodelete &&
1790 !elm->obj->ref_nodel) {
1791 dbg("obj %s nodelete", elm->obj->path);
1794 elm->obj->ref_nodel = true;
1799 * Initialize the dynamic linker. The argument is the address at which
1800 * the dynamic linker has been mapped into memory. The primary task of
1801 * this function is to relocate the dynamic linker.
1804 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1806 Obj_Entry objtmp; /* Temporary rtld object */
1807 const Elf_Dyn *dyn_rpath;
1808 const Elf_Dyn *dyn_soname;
1809 const Elf_Dyn *dyn_runpath;
1811 #ifdef RTLD_INIT_PAGESIZES_EARLY
1812 /* The page size is required by the dynamic memory allocator. */
1813 init_pagesizes(aux_info);
1817 * Conjure up an Obj_Entry structure for the dynamic linker.
1819 * The "path" member can't be initialized yet because string constants
1820 * cannot yet be accessed. Below we will set it correctly.
1822 memset(&objtmp, 0, sizeof(objtmp));
1825 objtmp.mapbase = mapbase;
1827 objtmp.relocbase = mapbase;
1829 if (RTLD_IS_DYNAMIC()) {
1830 objtmp.dynamic = rtld_dynamic(&objtmp);
1831 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1832 assert(objtmp.needed == NULL);
1833 #if !defined(__mips__)
1834 /* MIPS has a bogus DT_TEXTREL. */
1835 assert(!objtmp.textrel);
1839 * Temporarily put the dynamic linker entry into the object list, so
1840 * that symbols can be found.
1843 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1846 /* Initialize the object list. */
1847 obj_tail = &obj_list;
1849 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1850 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1852 #ifndef RTLD_INIT_PAGESIZES_EARLY
1853 /* The page size is required by the dynamic memory allocator. */
1854 init_pagesizes(aux_info);
1857 if (aux_info[AT_OSRELDATE] != NULL)
1858 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1860 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1862 /* Replace the path with a dynamically allocated copy. */
1863 obj_rtld.path = xstrdup(PATH_RTLD);
1865 r_debug.r_brk = r_debug_state;
1866 r_debug.r_state = RT_CONSISTENT;
1870 * Retrieve the array of supported page sizes. The kernel provides the page
1871 * sizes in increasing order.
1874 init_pagesizes(Elf_Auxinfo **aux_info)
1876 static size_t psa[MAXPAGESIZES];
1880 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1882 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1883 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1886 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1889 /* As a fallback, retrieve the base page size. */
1890 size = sizeof(psa[0]);
1891 if (aux_info[AT_PAGESZ] != NULL) {
1892 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1896 mib[1] = HW_PAGESIZE;
1900 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1901 _rtld_error("sysctl for hw.pagesize(s) failed");
1907 npagesizes = size / sizeof(pagesizes[0]);
1908 /* Discard any invalid entries at the end of the array. */
1909 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1914 * Add the init functions from a needed object list (and its recursive
1915 * needed objects) to "list". This is not used directly; it is a helper
1916 * function for initlist_add_objects(). The write lock must be held
1917 * when this function is called.
1920 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1922 /* Recursively process the successor needed objects. */
1923 if (needed->next != NULL)
1924 initlist_add_neededs(needed->next, list);
1926 /* Process the current needed object. */
1927 if (needed->obj != NULL)
1928 initlist_add_objects(needed->obj, &needed->obj->next, list);
1932 * Scan all of the DAGs rooted in the range of objects from "obj" to
1933 * "tail" and add their init functions to "list". This recurses over
1934 * the DAGs and ensure the proper init ordering such that each object's
1935 * needed libraries are initialized before the object itself. At the
1936 * same time, this function adds the objects to the global finalization
1937 * list "list_fini" in the opposite order. The write lock must be
1938 * held when this function is called.
1941 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1944 if (obj->init_scanned || obj->init_done)
1946 obj->init_scanned = true;
1948 /* Recursively process the successor objects. */
1949 if (&obj->next != tail)
1950 initlist_add_objects(obj->next, tail, list);
1952 /* Recursively process the needed objects. */
1953 if (obj->needed != NULL)
1954 initlist_add_neededs(obj->needed, list);
1955 if (obj->needed_filtees != NULL)
1956 initlist_add_neededs(obj->needed_filtees, list);
1957 if (obj->needed_aux_filtees != NULL)
1958 initlist_add_neededs(obj->needed_aux_filtees, list);
1960 /* Add the object to the init list. */
1961 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1962 obj->init_array != (Elf_Addr)NULL)
1963 objlist_push_tail(list, obj);
1965 /* Add the object to the global fini list in the reverse order. */
1966 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1967 && !obj->on_fini_list) {
1968 objlist_push_head(&list_fini, obj);
1969 obj->on_fini_list = true;
1974 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1978 free_needed_filtees(Needed_Entry *n)
1980 Needed_Entry *needed, *needed1;
1982 for (needed = n; needed != NULL; needed = needed->next) {
1983 if (needed->obj != NULL) {
1984 dlclose(needed->obj);
1988 for (needed = n; needed != NULL; needed = needed1) {
1989 needed1 = needed->next;
1995 unload_filtees(Obj_Entry *obj)
1998 free_needed_filtees(obj->needed_filtees);
1999 obj->needed_filtees = NULL;
2000 free_needed_filtees(obj->needed_aux_filtees);
2001 obj->needed_aux_filtees = NULL;
2002 obj->filtees_loaded = false;
2006 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2007 RtldLockState *lockstate)
2010 for (; needed != NULL; needed = needed->next) {
2011 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2012 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2013 RTLD_LOCAL, lockstate);
2018 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2021 lock_restart_for_upgrade(lockstate);
2022 if (!obj->filtees_loaded) {
2023 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2024 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2025 obj->filtees_loaded = true;
2030 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2034 for (; needed != NULL; needed = needed->next) {
2035 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2036 flags & ~RTLD_LO_NOLOAD);
2037 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2044 * Given a shared object, traverse its list of needed objects, and load
2045 * each of them. Returns 0 on success. Generates an error message and
2046 * returns -1 on failure.
2049 load_needed_objects(Obj_Entry *first, int flags)
2053 for (obj = first; obj != NULL; obj = obj->next) {
2054 if (process_needed(obj, obj->needed, flags) == -1)
2061 load_preload_objects(void)
2063 char *p = ld_preload;
2065 static const char delim[] = " \t:;";
2070 p += strspn(p, delim);
2071 while (*p != '\0') {
2072 size_t len = strcspn(p, delim);
2077 obj = load_object(p, -1, NULL, 0);
2079 return -1; /* XXX - cleanup */
2080 obj->z_interpose = true;
2083 p += strspn(p, delim);
2085 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2090 printable_path(const char *path)
2093 return (path == NULL ? "<unknown>" : path);
2097 * Load a shared object into memory, if it is not already loaded. The
2098 * object may be specified by name or by user-supplied file descriptor
2099 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2102 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2106 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2115 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2116 if (object_match_name(obj, name))
2120 path = find_library(name, refobj, &fd);
2128 * search_library_pathfds() opens a fresh file descriptor for the
2129 * library, so there is no need to dup().
2131 } else if (fd_u == -1) {
2133 * If we didn't find a match by pathname, or the name is not
2134 * supplied, open the file and check again by device and inode.
2135 * This avoids false mismatches caused by multiple links or ".."
2138 * To avoid a race, we open the file and use fstat() rather than
2141 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2142 _rtld_error("Cannot open \"%s\"", path);
2147 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2149 _rtld_error("Cannot dup fd");
2154 if (fstat(fd, &sb) == -1) {
2155 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2160 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2161 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2163 if (obj != NULL && name != NULL) {
2164 object_add_name(obj, name);
2169 if (flags & RTLD_LO_NOLOAD) {
2175 /* First use of this object, so we must map it in */
2176 obj = do_load_object(fd, name, path, &sb, flags);
2185 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2192 * but first, make sure that environment variables haven't been
2193 * used to circumvent the noexec flag on a filesystem.
2195 if (dangerous_ld_env) {
2196 if (fstatfs(fd, &fs) != 0) {
2197 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2200 if (fs.f_flags & MNT_NOEXEC) {
2201 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2205 dbg("loading \"%s\"", printable_path(path));
2206 obj = map_object(fd, printable_path(path), sbp);
2211 * If DT_SONAME is present in the object, digest_dynamic2 already
2212 * added it to the object names.
2215 object_add_name(obj, name);
2217 digest_dynamic(obj, 0);
2218 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2219 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2220 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2222 dbg("refusing to load non-loadable \"%s\"", obj->path);
2223 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2224 munmap(obj->mapbase, obj->mapsize);
2229 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2231 obj_tail = &obj->next;
2234 linkmap_add(obj); /* for GDB & dlinfo() */
2235 max_stack_flags |= obj->stack_flags;
2237 dbg(" %p .. %p: %s", obj->mapbase,
2238 obj->mapbase + obj->mapsize - 1, obj->path);
2240 dbg(" WARNING: %s has impure text", obj->path);
2241 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2248 obj_from_addr(const void *addr)
2252 for (obj = obj_list; obj != NULL; obj = obj->next) {
2253 if (addr < (void *) obj->mapbase)
2255 if (addr < (void *) (obj->mapbase + obj->mapsize))
2264 Elf_Addr *preinit_addr;
2267 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2268 if (preinit_addr == NULL)
2271 for (index = 0; index < obj_main->preinit_array_num; index++) {
2272 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2273 dbg("calling preinit function for %s at %p", obj_main->path,
2274 (void *)preinit_addr[index]);
2275 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2276 0, 0, obj_main->path);
2277 call_init_pointer(obj_main, preinit_addr[index]);
2283 * Call the finalization functions for each of the objects in "list"
2284 * belonging to the DAG of "root" and referenced once. If NULL "root"
2285 * is specified, every finalization function will be called regardless
2286 * of the reference count and the list elements won't be freed. All of
2287 * the objects are expected to have non-NULL fini functions.
2290 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2294 Elf_Addr *fini_addr;
2297 assert(root == NULL || root->refcount == 1);
2300 * Preserve the current error message since a fini function might
2301 * call into the dynamic linker and overwrite it.
2303 saved_msg = errmsg_save();
2305 STAILQ_FOREACH(elm, list, link) {
2306 if (root != NULL && (elm->obj->refcount != 1 ||
2307 objlist_find(&root->dagmembers, elm->obj) == NULL))
2309 /* Remove object from fini list to prevent recursive invocation. */
2310 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2312 * XXX: If a dlopen() call references an object while the
2313 * fini function is in progress, we might end up trying to
2314 * unload the referenced object in dlclose() or the object
2315 * won't be unloaded although its fini function has been
2318 lock_release(rtld_bind_lock, lockstate);
2321 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2322 * When this happens, DT_FINI_ARRAY is processed first.
2324 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2325 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2326 for (index = elm->obj->fini_array_num - 1; index >= 0;
2328 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2329 dbg("calling fini function for %s at %p",
2330 elm->obj->path, (void *)fini_addr[index]);
2331 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2332 (void *)fini_addr[index], 0, 0, elm->obj->path);
2333 call_initfini_pointer(elm->obj, fini_addr[index]);
2337 if (elm->obj->fini != (Elf_Addr)NULL) {
2338 dbg("calling fini function for %s at %p", elm->obj->path,
2339 (void *)elm->obj->fini);
2340 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2341 0, 0, elm->obj->path);
2342 call_initfini_pointer(elm->obj, elm->obj->fini);
2344 wlock_acquire(rtld_bind_lock, lockstate);
2345 /* No need to free anything if process is going down. */
2349 * We must restart the list traversal after every fini call
2350 * because a dlclose() call from the fini function or from
2351 * another thread might have modified the reference counts.
2355 } while (elm != NULL);
2356 errmsg_restore(saved_msg);
2360 * Call the initialization functions for each of the objects in
2361 * "list". All of the objects are expected to have non-NULL init
2365 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2370 Elf_Addr *init_addr;
2374 * Clean init_scanned flag so that objects can be rechecked and
2375 * possibly initialized earlier if any of vectors called below
2376 * cause the change by using dlopen.
2378 for (obj = obj_list; obj != NULL; obj = obj->next)
2379 obj->init_scanned = false;
2382 * Preserve the current error message since an init function might
2383 * call into the dynamic linker and overwrite it.
2385 saved_msg = errmsg_save();
2386 STAILQ_FOREACH(elm, list, link) {
2387 if (elm->obj->init_done) /* Initialized early. */
2390 * Race: other thread might try to use this object before current
2391 * one completes the initilization. Not much can be done here
2392 * without better locking.
2394 elm->obj->init_done = true;
2395 lock_release(rtld_bind_lock, lockstate);
2398 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2399 * When this happens, DT_INIT is processed first.
2401 if (elm->obj->init != (Elf_Addr)NULL) {
2402 dbg("calling init function for %s at %p", elm->obj->path,
2403 (void *)elm->obj->init);
2404 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2405 0, 0, elm->obj->path);
2406 call_initfini_pointer(elm->obj, elm->obj->init);
2408 init_addr = (Elf_Addr *)elm->obj->init_array;
2409 if (init_addr != NULL) {
2410 for (index = 0; index < elm->obj->init_array_num; index++) {
2411 if (init_addr[index] != 0 && init_addr[index] != 1) {
2412 dbg("calling init function for %s at %p", elm->obj->path,
2413 (void *)init_addr[index]);
2414 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2415 (void *)init_addr[index], 0, 0, elm->obj->path);
2416 call_init_pointer(elm->obj, init_addr[index]);
2420 wlock_acquire(rtld_bind_lock, lockstate);
2422 errmsg_restore(saved_msg);
2426 objlist_clear(Objlist *list)
2430 while (!STAILQ_EMPTY(list)) {
2431 elm = STAILQ_FIRST(list);
2432 STAILQ_REMOVE_HEAD(list, link);
2437 static Objlist_Entry *
2438 objlist_find(Objlist *list, const Obj_Entry *obj)
2442 STAILQ_FOREACH(elm, list, link)
2443 if (elm->obj == obj)
2449 objlist_init(Objlist *list)
2455 objlist_push_head(Objlist *list, Obj_Entry *obj)
2459 elm = NEW(Objlist_Entry);
2461 STAILQ_INSERT_HEAD(list, elm, link);
2465 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2469 elm = NEW(Objlist_Entry);
2471 STAILQ_INSERT_TAIL(list, elm, link);
2475 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2477 Objlist_Entry *elm, *listelm;
2479 STAILQ_FOREACH(listelm, list, link) {
2480 if (listelm->obj == listobj)
2483 elm = NEW(Objlist_Entry);
2485 if (listelm != NULL)
2486 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2488 STAILQ_INSERT_TAIL(list, elm, link);
2492 objlist_remove(Objlist *list, Obj_Entry *obj)
2496 if ((elm = objlist_find(list, obj)) != NULL) {
2497 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2503 * Relocate dag rooted in the specified object.
2504 * Returns 0 on success, or -1 on failure.
2508 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2509 int flags, RtldLockState *lockstate)
2515 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2516 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2525 * Relocate single object.
2526 * Returns 0 on success, or -1 on failure.
2529 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2530 int flags, RtldLockState *lockstate)
2535 obj->relocated = true;
2537 dbg("relocating \"%s\"", obj->path);
2539 if (obj->symtab == NULL || obj->strtab == NULL ||
2540 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2541 _rtld_error("%s: Shared object has no run-time symbol table",
2547 /* There are relocations to the write-protected text segment. */
2548 if (mprotect(obj->mapbase, obj->textsize,
2549 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2550 _rtld_error("%s: Cannot write-enable text segment: %s",
2551 obj->path, rtld_strerror(errno));
2556 /* Process the non-PLT non-IFUNC relocations. */
2557 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2560 if (obj->textrel) { /* Re-protected the text segment. */
2561 if (mprotect(obj->mapbase, obj->textsize,
2562 PROT_READ|PROT_EXEC) == -1) {
2563 _rtld_error("%s: Cannot write-protect text segment: %s",
2564 obj->path, rtld_strerror(errno));
2569 /* Set the special PLT or GOT entries. */
2572 /* Process the PLT relocations. */
2573 if (reloc_plt(obj) == -1)
2575 /* Relocate the jump slots if we are doing immediate binding. */
2576 if (obj->bind_now || bind_now)
2577 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2581 * Process the non-PLT IFUNC relocations. The relocations are
2582 * processed in two phases, because IFUNC resolvers may
2583 * reference other symbols, which must be readily processed
2584 * before resolvers are called.
2586 if (obj->non_plt_gnu_ifunc &&
2587 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2590 if (obj->relro_size > 0) {
2591 if (mprotect(obj->relro_page, obj->relro_size,
2593 _rtld_error("%s: Cannot enforce relro protection: %s",
2594 obj->path, rtld_strerror(errno));
2600 * Set up the magic number and version in the Obj_Entry. These
2601 * were checked in the crt1.o from the original ElfKit, so we
2602 * set them for backward compatibility.
2604 obj->magic = RTLD_MAGIC;
2605 obj->version = RTLD_VERSION;
2611 * Relocate newly-loaded shared objects. The argument is a pointer to
2612 * the Obj_Entry for the first such object. All objects from the first
2613 * to the end of the list of objects are relocated. Returns 0 on success,
2617 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2618 int flags, RtldLockState *lockstate)
2623 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2624 error = relocate_object(obj, bind_now, rtldobj, flags,
2633 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2634 * referencing STT_GNU_IFUNC symbols is postponed till the other
2635 * relocations are done. The indirect functions specified as
2636 * ifunc are allowed to call other symbols, so we need to have
2637 * objects relocated before asking for resolution from indirects.
2639 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2640 * instead of the usual lazy handling of PLT slots. It is
2641 * consistent with how GNU does it.
2644 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2645 RtldLockState *lockstate)
2647 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2649 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2650 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2656 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2657 RtldLockState *lockstate)
2661 for (obj = first; obj != NULL; obj = obj->next) {
2662 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2669 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2670 RtldLockState *lockstate)
2674 STAILQ_FOREACH(elm, list, link) {
2675 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2683 * Cleanup procedure. It will be called (by the atexit mechanism) just
2684 * before the process exits.
2689 RtldLockState lockstate;
2691 wlock_acquire(rtld_bind_lock, &lockstate);
2693 objlist_call_fini(&list_fini, NULL, &lockstate);
2694 /* No need to remove the items from the list, since we are exiting. */
2695 if (!libmap_disable)
2697 lock_release(rtld_bind_lock, &lockstate);
2701 * Iterate over a search path, translate each element, and invoke the
2702 * callback on the result.
2705 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2711 path += strspn(path, ":;");
2712 while (*path != '\0') {
2716 len = strcspn(path, ":;");
2717 trans = lm_findn(NULL, path, len);
2719 res = callback(trans, strlen(trans), arg);
2721 res = callback(path, len, arg);
2727 path += strspn(path, ":;");
2733 struct try_library_args {
2741 try_library_path(const char *dir, size_t dirlen, void *param)
2743 struct try_library_args *arg;
2746 if (*dir == '/' || trust) {
2749 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2752 pathname = arg->buffer;
2753 strncpy(pathname, dir, dirlen);
2754 pathname[dirlen] = '/';
2755 strcpy(pathname + dirlen + 1, arg->name);
2757 dbg(" Trying \"%s\"", pathname);
2758 if (access(pathname, F_OK) == 0) { /* We found it */
2759 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2760 strcpy(pathname, arg->buffer);
2768 search_library_path(const char *name, const char *path)
2771 struct try_library_args arg;
2777 arg.namelen = strlen(name);
2778 arg.buffer = xmalloc(PATH_MAX);
2779 arg.buflen = PATH_MAX;
2781 p = path_enumerate(path, try_library_path, &arg);
2790 * Finds the library with the given name using the directory descriptors
2791 * listed in the LD_LIBRARY_PATH_FDS environment variable.
2793 * Returns a freshly-opened close-on-exec file descriptor for the library,
2794 * or -1 if the library cannot be found.
2797 search_library_pathfds(const char *name, const char *path, int *fdp)
2799 char *envcopy, *fdstr, *found, *last_token;
2803 dbg("%s('%s', '%s', fdp)", __func__, name, path);
2805 /* Don't load from user-specified libdirs into setuid binaries. */
2809 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
2813 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
2814 if (name[0] == '/') {
2815 dbg("Absolute path (%s) passed to %s", name, __func__);
2820 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
2821 * copy of the path, as strtok_r rewrites separator tokens
2825 envcopy = xstrdup(path);
2826 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
2827 fdstr = strtok_r(NULL, ":", &last_token)) {
2828 dirfd = parse_libdir(fdstr);
2831 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC);
2834 len = strlen(fdstr) + strlen(name) + 3;
2835 found = xmalloc(len);
2836 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
2837 _rtld_error("error generating '%d/%s'",
2841 dbg("open('%s') => %d", found, fd);
2852 dlclose(void *handle)
2855 RtldLockState lockstate;
2857 wlock_acquire(rtld_bind_lock, &lockstate);
2858 root = dlcheck(handle);
2860 lock_release(rtld_bind_lock, &lockstate);
2863 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2866 /* Unreference the object and its dependencies. */
2867 root->dl_refcount--;
2869 if (root->refcount == 1) {
2871 * The object will be no longer referenced, so we must unload it.
2872 * First, call the fini functions.
2874 objlist_call_fini(&list_fini, root, &lockstate);
2878 /* Finish cleaning up the newly-unreferenced objects. */
2879 GDB_STATE(RT_DELETE,&root->linkmap);
2880 unload_object(root);
2881 GDB_STATE(RT_CONSISTENT,NULL);
2885 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2886 lock_release(rtld_bind_lock, &lockstate);
2893 char *msg = error_message;
2894 error_message = NULL;
2899 * This function is deprecated and has no effect.
2902 dllockinit(void *context,
2903 void *(*lock_create)(void *context),
2904 void (*rlock_acquire)(void *lock),
2905 void (*wlock_acquire)(void *lock),
2906 void (*lock_release)(void *lock),
2907 void (*lock_destroy)(void *lock),
2908 void (*context_destroy)(void *context))
2910 static void *cur_context;
2911 static void (*cur_context_destroy)(void *);
2913 /* Just destroy the context from the previous call, if necessary. */
2914 if (cur_context_destroy != NULL)
2915 cur_context_destroy(cur_context);
2916 cur_context = context;
2917 cur_context_destroy = context_destroy;
2921 dlopen(const char *name, int mode)
2924 return (rtld_dlopen(name, -1, mode));
2928 fdlopen(int fd, int mode)
2931 return (rtld_dlopen(NULL, fd, mode));
2935 rtld_dlopen(const char *name, int fd, int mode)
2937 RtldLockState lockstate;
2940 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2941 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2942 if (ld_tracing != NULL) {
2943 rlock_acquire(rtld_bind_lock, &lockstate);
2944 if (sigsetjmp(lockstate.env, 0) != 0)
2945 lock_upgrade(rtld_bind_lock, &lockstate);
2946 environ = (char **)*get_program_var_addr("environ", &lockstate);
2947 lock_release(rtld_bind_lock, &lockstate);
2949 lo_flags = RTLD_LO_DLOPEN;
2950 if (mode & RTLD_NODELETE)
2951 lo_flags |= RTLD_LO_NODELETE;
2952 if (mode & RTLD_NOLOAD)
2953 lo_flags |= RTLD_LO_NOLOAD;
2954 if (ld_tracing != NULL)
2955 lo_flags |= RTLD_LO_TRACE;
2957 return (dlopen_object(name, fd, obj_main, lo_flags,
2958 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2962 dlopen_cleanup(Obj_Entry *obj)
2967 if (obj->refcount == 0)
2972 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2973 int mode, RtldLockState *lockstate)
2975 Obj_Entry **old_obj_tail;
2978 RtldLockState mlockstate;
2981 objlist_init(&initlist);
2983 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2984 wlock_acquire(rtld_bind_lock, &mlockstate);
2985 lockstate = &mlockstate;
2987 GDB_STATE(RT_ADD,NULL);
2989 old_obj_tail = obj_tail;
2991 if (name == NULL && fd == -1) {
2995 obj = load_object(name, fd, refobj, lo_flags);
3000 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3001 objlist_push_tail(&list_global, obj);
3002 if (*old_obj_tail != NULL) { /* We loaded something new. */
3003 assert(*old_obj_tail == obj);
3004 result = load_needed_objects(obj,
3005 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3009 result = rtld_verify_versions(&obj->dagmembers);
3010 if (result != -1 && ld_tracing)
3012 if (result == -1 || relocate_object_dag(obj,
3013 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3014 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3016 dlopen_cleanup(obj);
3018 } else if (lo_flags & RTLD_LO_EARLY) {
3020 * Do not call the init functions for early loaded
3021 * filtees. The image is still not initialized enough
3024 * Our object is found by the global object list and
3025 * will be ordered among all init calls done right
3026 * before transferring control to main.
3029 /* Make list of init functions to call. */
3030 initlist_add_objects(obj, &obj->next, &initlist);
3033 * Process all no_delete objects here, given them own
3034 * DAGs to prevent their dependencies from being unloaded.
3035 * This has to be done after we have loaded all of the
3036 * dependencies, so that we do not miss any.
3039 process_nodelete(obj);
3042 * Bump the reference counts for objects on this DAG. If
3043 * this is the first dlopen() call for the object that was
3044 * already loaded as a dependency, initialize the dag
3050 if ((lo_flags & RTLD_LO_TRACE) != 0)
3053 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3054 obj->z_nodelete) && !obj->ref_nodel) {
3055 dbg("obj %s nodelete", obj->path);
3057 obj->z_nodelete = obj->ref_nodel = true;
3061 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3063 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3065 if (!(lo_flags & RTLD_LO_EARLY)) {
3066 map_stacks_exec(lockstate);
3069 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3070 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3072 objlist_clear(&initlist);
3073 dlopen_cleanup(obj);
3074 if (lockstate == &mlockstate)
3075 lock_release(rtld_bind_lock, lockstate);
3079 if (!(lo_flags & RTLD_LO_EARLY)) {
3080 /* Call the init functions. */
3081 objlist_call_init(&initlist, lockstate);
3083 objlist_clear(&initlist);
3084 if (lockstate == &mlockstate)
3085 lock_release(rtld_bind_lock, lockstate);
3088 trace_loaded_objects(obj);
3089 if (lockstate == &mlockstate)
3090 lock_release(rtld_bind_lock, lockstate);
3095 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3099 const Obj_Entry *obj, *defobj;
3102 RtldLockState lockstate;
3109 symlook_init(&req, name);
3111 req.flags = flags | SYMLOOK_IN_PLT;
3112 req.lockstate = &lockstate;
3114 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3115 rlock_acquire(rtld_bind_lock, &lockstate);
3116 if (sigsetjmp(lockstate.env, 0) != 0)
3117 lock_upgrade(rtld_bind_lock, &lockstate);
3118 if (handle == NULL || handle == RTLD_NEXT ||
3119 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3121 if ((obj = obj_from_addr(retaddr)) == NULL) {
3122 _rtld_error("Cannot determine caller's shared object");
3123 lock_release(rtld_bind_lock, &lockstate);
3124 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3127 if (handle == NULL) { /* Just the caller's shared object. */
3128 res = symlook_obj(&req, obj);
3131 defobj = req.defobj_out;
3133 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3134 handle == RTLD_SELF) { /* ... caller included */
3135 if (handle == RTLD_NEXT)
3137 for (; obj != NULL; obj = obj->next) {
3138 res = symlook_obj(&req, obj);
3141 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3143 defobj = req.defobj_out;
3144 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3150 * Search the dynamic linker itself, and possibly resolve the
3151 * symbol from there. This is how the application links to
3152 * dynamic linker services such as dlopen.
3154 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3155 res = symlook_obj(&req, &obj_rtld);
3158 defobj = req.defobj_out;
3162 assert(handle == RTLD_DEFAULT);
3163 res = symlook_default(&req, obj);
3165 defobj = req.defobj_out;
3170 if ((obj = dlcheck(handle)) == NULL) {
3171 lock_release(rtld_bind_lock, &lockstate);
3172 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3176 donelist_init(&donelist);
3177 if (obj->mainprog) {
3178 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3179 res = symlook_global(&req, &donelist);
3182 defobj = req.defobj_out;
3185 * Search the dynamic linker itself, and possibly resolve the
3186 * symbol from there. This is how the application links to
3187 * dynamic linker services such as dlopen.
3189 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3190 res = symlook_obj(&req, &obj_rtld);
3193 defobj = req.defobj_out;
3198 /* Search the whole DAG rooted at the given object. */
3199 res = symlook_list(&req, &obj->dagmembers, &donelist);
3202 defobj = req.defobj_out;
3208 lock_release(rtld_bind_lock, &lockstate);
3211 * The value required by the caller is derived from the value
3212 * of the symbol. this is simply the relocated value of the
3215 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3216 sym = make_function_pointer(def, defobj);
3217 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3218 sym = rtld_resolve_ifunc(defobj, def);
3219 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3220 ti.ti_module = defobj->tlsindex;
3221 ti.ti_offset = def->st_value;
3222 sym = __tls_get_addr(&ti);
3224 sym = defobj->relocbase + def->st_value;
3225 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3229 _rtld_error("Undefined symbol \"%s\"", name);
3230 lock_release(rtld_bind_lock, &lockstate);
3231 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3236 dlsym(void *handle, const char *name)
3238 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3243 dlfunc(void *handle, const char *name)
3250 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3256 dlvsym(void *handle, const char *name, const char *version)
3260 ventry.name = version;
3262 ventry.hash = elf_hash(version);
3264 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3269 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3271 const Obj_Entry *obj;
3272 RtldLockState lockstate;
3274 rlock_acquire(rtld_bind_lock, &lockstate);
3275 obj = obj_from_addr(addr);
3277 _rtld_error("No shared object contains address");
3278 lock_release(rtld_bind_lock, &lockstate);
3281 rtld_fill_dl_phdr_info(obj, phdr_info);
3282 lock_release(rtld_bind_lock, &lockstate);
3287 dladdr(const void *addr, Dl_info *info)
3289 const Obj_Entry *obj;
3292 unsigned long symoffset;
3293 RtldLockState lockstate;
3295 rlock_acquire(rtld_bind_lock, &lockstate);
3296 obj = obj_from_addr(addr);
3298 _rtld_error("No shared object contains address");
3299 lock_release(rtld_bind_lock, &lockstate);
3302 info->dli_fname = obj->path;
3303 info->dli_fbase = obj->mapbase;
3304 info->dli_saddr = (void *)0;
3305 info->dli_sname = NULL;
3308 * Walk the symbol list looking for the symbol whose address is
3309 * closest to the address sent in.
3311 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3312 def = obj->symtab + symoffset;
3315 * For skip the symbol if st_shndx is either SHN_UNDEF or
3318 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3322 * If the symbol is greater than the specified address, or if it
3323 * is further away from addr than the current nearest symbol,
3326 symbol_addr = obj->relocbase + def->st_value;
3327 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3330 /* Update our idea of the nearest symbol. */
3331 info->dli_sname = obj->strtab + def->st_name;
3332 info->dli_saddr = symbol_addr;
3335 if (info->dli_saddr == addr)
3338 lock_release(rtld_bind_lock, &lockstate);
3343 dlinfo(void *handle, int request, void *p)
3345 const Obj_Entry *obj;
3346 RtldLockState lockstate;
3349 rlock_acquire(rtld_bind_lock, &lockstate);
3351 if (handle == NULL || handle == RTLD_SELF) {
3354 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3355 if ((obj = obj_from_addr(retaddr)) == NULL)
3356 _rtld_error("Cannot determine caller's shared object");
3358 obj = dlcheck(handle);
3361 lock_release(rtld_bind_lock, &lockstate);
3367 case RTLD_DI_LINKMAP:
3368 *((struct link_map const **)p) = &obj->linkmap;
3370 case RTLD_DI_ORIGIN:
3371 error = rtld_dirname(obj->path, p);
3374 case RTLD_DI_SERINFOSIZE:
3375 case RTLD_DI_SERINFO:
3376 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3380 _rtld_error("Invalid request %d passed to dlinfo()", request);
3384 lock_release(rtld_bind_lock, &lockstate);
3390 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3393 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3394 phdr_info->dlpi_name = obj->path;
3395 phdr_info->dlpi_phdr = obj->phdr;
3396 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3397 phdr_info->dlpi_tls_modid = obj->tlsindex;
3398 phdr_info->dlpi_tls_data = obj->tlsinit;
3399 phdr_info->dlpi_adds = obj_loads;
3400 phdr_info->dlpi_subs = obj_loads - obj_count;
3404 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3406 struct dl_phdr_info phdr_info;
3407 const Obj_Entry *obj;
3408 RtldLockState bind_lockstate, phdr_lockstate;
3411 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3412 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3416 for (obj = obj_list; obj != NULL; obj = obj->next) {
3417 rtld_fill_dl_phdr_info(obj, &phdr_info);
3418 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3423 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3424 error = callback(&phdr_info, sizeof(phdr_info), param);
3427 lock_release(rtld_bind_lock, &bind_lockstate);
3428 lock_release(rtld_phdr_lock, &phdr_lockstate);
3434 fill_search_info(const char *dir, size_t dirlen, void *param)
3436 struct fill_search_info_args *arg;
3440 if (arg->request == RTLD_DI_SERINFOSIZE) {
3441 arg->serinfo->dls_cnt ++;
3442 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3444 struct dl_serpath *s_entry;
3446 s_entry = arg->serpath;
3447 s_entry->dls_name = arg->strspace;
3448 s_entry->dls_flags = arg->flags;
3450 strncpy(arg->strspace, dir, dirlen);
3451 arg->strspace[dirlen] = '\0';
3453 arg->strspace += dirlen + 1;
3461 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3463 struct dl_serinfo _info;
3464 struct fill_search_info_args args;
3466 args.request = RTLD_DI_SERINFOSIZE;
3467 args.serinfo = &_info;
3469 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3472 path_enumerate(obj->rpath, fill_search_info, &args);
3473 path_enumerate(ld_library_path, fill_search_info, &args);
3474 path_enumerate(obj->runpath, fill_search_info, &args);
3475 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3476 if (!obj->z_nodeflib)
3477 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3480 if (request == RTLD_DI_SERINFOSIZE) {
3481 info->dls_size = _info.dls_size;
3482 info->dls_cnt = _info.dls_cnt;
3486 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3487 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3491 args.request = RTLD_DI_SERINFO;
3492 args.serinfo = info;
3493 args.serpath = &info->dls_serpath[0];
3494 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3496 args.flags = LA_SER_RUNPATH;
3497 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3500 args.flags = LA_SER_LIBPATH;
3501 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3504 args.flags = LA_SER_RUNPATH;
3505 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3508 args.flags = LA_SER_CONFIG;
3509 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3513 args.flags = LA_SER_DEFAULT;
3514 if (!obj->z_nodeflib &&
3515 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3521 rtld_dirname(const char *path, char *bname)
3525 /* Empty or NULL string gets treated as "." */
3526 if (path == NULL || *path == '\0') {
3532 /* Strip trailing slashes */
3533 endp = path + strlen(path) - 1;
3534 while (endp > path && *endp == '/')
3537 /* Find the start of the dir */
3538 while (endp > path && *endp != '/')
3541 /* Either the dir is "/" or there are no slashes */
3543 bname[0] = *endp == '/' ? '/' : '.';
3549 } while (endp > path && *endp == '/');
3552 if (endp - path + 2 > PATH_MAX)
3554 _rtld_error("Filename is too long: %s", path);
3558 strncpy(bname, path, endp - path + 1);
3559 bname[endp - path + 1] = '\0';
3564 rtld_dirname_abs(const char *path, char *base)
3566 char base_rel[PATH_MAX];
3568 if (rtld_dirname(path, base) == -1)
3572 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3573 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3574 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3576 strcpy(base, base_rel);
3581 linkmap_add(Obj_Entry *obj)
3583 struct link_map *l = &obj->linkmap;
3584 struct link_map *prev;
3586 obj->linkmap.l_name = obj->path;
3587 obj->linkmap.l_addr = obj->mapbase;
3588 obj->linkmap.l_ld = obj->dynamic;
3590 /* GDB needs load offset on MIPS to use the symbols */
3591 obj->linkmap.l_offs = obj->relocbase;
3594 if (r_debug.r_map == NULL) {
3600 * Scan to the end of the list, but not past the entry for the
3601 * dynamic linker, which we want to keep at the very end.
3603 for (prev = r_debug.r_map;
3604 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3605 prev = prev->l_next)
3608 /* Link in the new entry. */
3610 l->l_next = prev->l_next;
3611 if (l->l_next != NULL)
3612 l->l_next->l_prev = l;
3617 linkmap_delete(Obj_Entry *obj)
3619 struct link_map *l = &obj->linkmap;
3621 if (l->l_prev == NULL) {
3622 if ((r_debug.r_map = l->l_next) != NULL)
3623 l->l_next->l_prev = NULL;
3627 if ((l->l_prev->l_next = l->l_next) != NULL)
3628 l->l_next->l_prev = l->l_prev;
3632 * Function for the debugger to set a breakpoint on to gain control.
3634 * The two parameters allow the debugger to easily find and determine
3635 * what the runtime loader is doing and to whom it is doing it.
3637 * When the loadhook trap is hit (r_debug_state, set at program
3638 * initialization), the arguments can be found on the stack:
3640 * +8 struct link_map *m
3641 * +4 struct r_debug *rd
3645 r_debug_state(struct r_debug* rd, struct link_map *m)
3648 * The following is a hack to force the compiler to emit calls to
3649 * this function, even when optimizing. If the function is empty,
3650 * the compiler is not obliged to emit any code for calls to it,
3651 * even when marked __noinline. However, gdb depends on those
3654 __compiler_membar();
3658 * A function called after init routines have completed. This can be used to
3659 * break before a program's entry routine is called, and can be used when
3660 * main is not available in the symbol table.
3663 _r_debug_postinit(struct link_map *m)
3666 /* See r_debug_state(). */
3667 __compiler_membar();
3671 * Get address of the pointer variable in the main program.
3672 * Prefer non-weak symbol over the weak one.
3674 static const void **
3675 get_program_var_addr(const char *name, RtldLockState *lockstate)
3680 symlook_init(&req, name);
3681 req.lockstate = lockstate;
3682 donelist_init(&donelist);
3683 if (symlook_global(&req, &donelist) != 0)
3685 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3686 return ((const void **)make_function_pointer(req.sym_out,
3688 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3689 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3691 return ((const void **)(req.defobj_out->relocbase +
3692 req.sym_out->st_value));
3696 * Set a pointer variable in the main program to the given value. This
3697 * is used to set key variables such as "environ" before any of the
3698 * init functions are called.
3701 set_program_var(const char *name, const void *value)
3705 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3706 dbg("\"%s\": *%p <-- %p", name, addr, value);
3712 * Search the global objects, including dependencies and main object,
3713 * for the given symbol.
3716 symlook_global(SymLook *req, DoneList *donelist)
3719 const Objlist_Entry *elm;
3722 symlook_init_from_req(&req1, req);
3724 /* Search all objects loaded at program start up. */
3725 if (req->defobj_out == NULL ||
3726 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3727 res = symlook_list(&req1, &list_main, donelist);
3728 if (res == 0 && (req->defobj_out == NULL ||
3729 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3730 req->sym_out = req1.sym_out;
3731 req->defobj_out = req1.defobj_out;
3732 assert(req->defobj_out != NULL);
3736 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3737 STAILQ_FOREACH(elm, &list_global, link) {
3738 if (req->defobj_out != NULL &&
3739 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3741 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3742 if (res == 0 && (req->defobj_out == NULL ||
3743 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3744 req->sym_out = req1.sym_out;
3745 req->defobj_out = req1.defobj_out;
3746 assert(req->defobj_out != NULL);
3750 return (req->sym_out != NULL ? 0 : ESRCH);
3754 * Given a symbol name in a referencing object, find the corresponding
3755 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3756 * no definition was found. Returns a pointer to the Obj_Entry of the
3757 * defining object via the reference parameter DEFOBJ_OUT.
3760 symlook_default(SymLook *req, const Obj_Entry *refobj)
3763 const Objlist_Entry *elm;
3767 donelist_init(&donelist);
3768 symlook_init_from_req(&req1, req);
3770 /* Look first in the referencing object if linked symbolically. */
3771 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3772 res = symlook_obj(&req1, refobj);
3774 req->sym_out = req1.sym_out;
3775 req->defobj_out = req1.defobj_out;
3776 assert(req->defobj_out != NULL);
3780 symlook_global(req, &donelist);
3782 /* Search all dlopened DAGs containing the referencing object. */
3783 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3784 if (req->sym_out != NULL &&
3785 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3787 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3788 if (res == 0 && (req->sym_out == NULL ||
3789 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3790 req->sym_out = req1.sym_out;
3791 req->defobj_out = req1.defobj_out;
3792 assert(req->defobj_out != NULL);
3797 * Search the dynamic linker itself, and possibly resolve the
3798 * symbol from there. This is how the application links to
3799 * dynamic linker services such as dlopen.
3801 if (req->sym_out == NULL ||
3802 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3803 res = symlook_obj(&req1, &obj_rtld);
3805 req->sym_out = req1.sym_out;
3806 req->defobj_out = req1.defobj_out;
3807 assert(req->defobj_out != NULL);
3811 return (req->sym_out != NULL ? 0 : ESRCH);
3815 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3818 const Obj_Entry *defobj;
3819 const Objlist_Entry *elm;
3825 STAILQ_FOREACH(elm, objlist, link) {
3826 if (donelist_check(dlp, elm->obj))
3828 symlook_init_from_req(&req1, req);
3829 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3830 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3832 defobj = req1.defobj_out;
3833 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3840 req->defobj_out = defobj;
3847 * Search the chain of DAGS cointed to by the given Needed_Entry
3848 * for a symbol of the given name. Each DAG is scanned completely
3849 * before advancing to the next one. Returns a pointer to the symbol,
3850 * or NULL if no definition was found.
3853 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3856 const Needed_Entry *n;
3857 const Obj_Entry *defobj;
3863 symlook_init_from_req(&req1, req);
3864 for (n = needed; n != NULL; n = n->next) {
3865 if (n->obj == NULL ||
3866 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3868 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3870 defobj = req1.defobj_out;
3871 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3877 req->defobj_out = defobj;
3884 * Search the symbol table of a single shared object for a symbol of
3885 * the given name and version, if requested. Returns a pointer to the
3886 * symbol, or NULL if no definition was found. If the object is
3887 * filter, return filtered symbol from filtee.
3889 * The symbol's hash value is passed in for efficiency reasons; that
3890 * eliminates many recomputations of the hash value.
3893 symlook_obj(SymLook *req, const Obj_Entry *obj)
3897 int flags, res, mres;
3900 * If there is at least one valid hash at this point, we prefer to
3901 * use the faster GNU version if available.
3903 if (obj->valid_hash_gnu)
3904 mres = symlook_obj1_gnu(req, obj);
3905 else if (obj->valid_hash_sysv)
3906 mres = symlook_obj1_sysv(req, obj);
3911 if (obj->needed_filtees != NULL) {
3912 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3913 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3914 donelist_init(&donelist);
3915 symlook_init_from_req(&req1, req);
3916 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3918 req->sym_out = req1.sym_out;
3919 req->defobj_out = req1.defobj_out;
3923 if (obj->needed_aux_filtees != NULL) {
3924 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3925 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3926 donelist_init(&donelist);
3927 symlook_init_from_req(&req1, req);
3928 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3930 req->sym_out = req1.sym_out;
3931 req->defobj_out = req1.defobj_out;
3939 /* Symbol match routine common to both hash functions */
3941 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3942 const unsigned long symnum)
3945 const Elf_Sym *symp;
3948 symp = obj->symtab + symnum;
3949 strp = obj->strtab + symp->st_name;
3951 switch (ELF_ST_TYPE(symp->st_info)) {
3957 if (symp->st_value == 0)
3961 if (symp->st_shndx != SHN_UNDEF)
3964 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3965 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3972 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3975 if (req->ventry == NULL) {
3976 if (obj->versyms != NULL) {
3977 verndx = VER_NDX(obj->versyms[symnum]);
3978 if (verndx > obj->vernum) {
3980 "%s: symbol %s references wrong version %d",
3981 obj->path, obj->strtab + symnum, verndx);
3985 * If we are not called from dlsym (i.e. this
3986 * is a normal relocation from unversioned
3987 * binary), accept the symbol immediately if
3988 * it happens to have first version after this
3989 * shared object became versioned. Otherwise,
3990 * if symbol is versioned and not hidden,
3991 * remember it. If it is the only symbol with
3992 * this name exported by the shared object, it
3993 * will be returned as a match by the calling
3994 * function. If symbol is global (verndx < 2)
3995 * accept it unconditionally.
3997 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3998 verndx == VER_NDX_GIVEN) {
3999 result->sym_out = symp;
4002 else if (verndx >= VER_NDX_GIVEN) {
4003 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4005 if (result->vsymp == NULL)
4006 result->vsymp = symp;
4012 result->sym_out = symp;
4015 if (obj->versyms == NULL) {
4016 if (object_match_name(obj, req->ventry->name)) {
4017 _rtld_error("%s: object %s should provide version %s "
4018 "for symbol %s", obj_rtld.path, obj->path,
4019 req->ventry->name, obj->strtab + symnum);
4023 verndx = VER_NDX(obj->versyms[symnum]);
4024 if (verndx > obj->vernum) {
4025 _rtld_error("%s: symbol %s references wrong version %d",
4026 obj->path, obj->strtab + symnum, verndx);
4029 if (obj->vertab[verndx].hash != req->ventry->hash ||
4030 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4032 * Version does not match. Look if this is a
4033 * global symbol and if it is not hidden. If
4034 * global symbol (verndx < 2) is available,
4035 * use it. Do not return symbol if we are
4036 * called by dlvsym, because dlvsym looks for
4037 * a specific version and default one is not
4038 * what dlvsym wants.
4040 if ((req->flags & SYMLOOK_DLSYM) ||
4041 (verndx >= VER_NDX_GIVEN) ||
4042 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4046 result->sym_out = symp;
4051 * Search for symbol using SysV hash function.
4052 * obj->buckets is known not to be NULL at this point; the test for this was
4053 * performed with the obj->valid_hash_sysv assignment.
4056 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4058 unsigned long symnum;
4059 Sym_Match_Result matchres;
4061 matchres.sym_out = NULL;
4062 matchres.vsymp = NULL;
4063 matchres.vcount = 0;
4065 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4066 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4067 if (symnum >= obj->nchains)
4068 return (ESRCH); /* Bad object */
4070 if (matched_symbol(req, obj, &matchres, symnum)) {
4071 req->sym_out = matchres.sym_out;
4072 req->defobj_out = obj;
4076 if (matchres.vcount == 1) {
4077 req->sym_out = matchres.vsymp;
4078 req->defobj_out = obj;
4084 /* Search for symbol using GNU hash function */
4086 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4088 Elf_Addr bloom_word;
4089 const Elf32_Word *hashval;
4091 Sym_Match_Result matchres;
4092 unsigned int h1, h2;
4093 unsigned long symnum;
4095 matchres.sym_out = NULL;
4096 matchres.vsymp = NULL;
4097 matchres.vcount = 0;
4099 /* Pick right bitmask word from Bloom filter array */
4100 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4101 obj->maskwords_bm_gnu];
4103 /* Calculate modulus word size of gnu hash and its derivative */
4104 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4105 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4107 /* Filter out the "definitely not in set" queries */
4108 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4111 /* Locate hash chain and corresponding value element*/
4112 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4115 hashval = &obj->chain_zero_gnu[bucket];
4117 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4118 symnum = hashval - obj->chain_zero_gnu;
4119 if (matched_symbol(req, obj, &matchres, symnum)) {
4120 req->sym_out = matchres.sym_out;
4121 req->defobj_out = obj;
4125 } while ((*hashval++ & 1) == 0);
4126 if (matchres.vcount == 1) {
4127 req->sym_out = matchres.vsymp;
4128 req->defobj_out = obj;
4135 trace_loaded_objects(Obj_Entry *obj)
4137 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4140 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4143 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4144 fmt1 = "\t%o => %p (%x)\n";
4146 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4147 fmt2 = "\t%o (%x)\n";
4149 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4151 for (; obj; obj = obj->next) {
4152 Needed_Entry *needed;
4156 if (list_containers && obj->needed != NULL)
4157 rtld_printf("%s:\n", obj->path);
4158 for (needed = obj->needed; needed; needed = needed->next) {
4159 if (needed->obj != NULL) {
4160 if (needed->obj->traced && !list_containers)
4162 needed->obj->traced = true;
4163 path = needed->obj->path;
4167 name = (char *)obj->strtab + needed->name;
4168 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4170 fmt = is_lib ? fmt1 : fmt2;
4171 while ((c = *fmt++) != '\0') {
4197 rtld_putstr(main_local);
4200 rtld_putstr(obj_main->path);
4207 rtld_printf("%d", sodp->sod_major);
4210 rtld_printf("%d", sodp->sod_minor);
4217 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4230 * Unload a dlopened object and its dependencies from memory and from
4231 * our data structures. It is assumed that the DAG rooted in the
4232 * object has already been unreferenced, and that the object has a
4233 * reference count of 0.
4236 unload_object(Obj_Entry *root)
4241 assert(root->refcount == 0);
4244 * Pass over the DAG removing unreferenced objects from
4245 * appropriate lists.
4247 unlink_object(root);
4249 /* Unmap all objects that are no longer referenced. */
4250 linkp = &obj_list->next;
4251 while ((obj = *linkp) != NULL) {
4252 if (obj->refcount == 0) {
4253 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4255 dbg("unloading \"%s\"", obj->path);
4256 unload_filtees(root);
4257 munmap(obj->mapbase, obj->mapsize);
4258 linkmap_delete(obj);
4269 unlink_object(Obj_Entry *root)
4273 if (root->refcount == 0) {
4274 /* Remove the object from the RTLD_GLOBAL list. */
4275 objlist_remove(&list_global, root);
4277 /* Remove the object from all objects' DAG lists. */
4278 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4279 objlist_remove(&elm->obj->dldags, root);
4280 if (elm->obj != root)
4281 unlink_object(elm->obj);
4287 ref_dag(Obj_Entry *root)
4291 assert(root->dag_inited);
4292 STAILQ_FOREACH(elm, &root->dagmembers, link)
4293 elm->obj->refcount++;
4297 unref_dag(Obj_Entry *root)
4301 assert(root->dag_inited);
4302 STAILQ_FOREACH(elm, &root->dagmembers, link)
4303 elm->obj->refcount--;
4307 * Common code for MD __tls_get_addr().
4309 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4311 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4313 Elf_Addr *newdtv, *dtv;
4314 RtldLockState lockstate;
4318 /* Check dtv generation in case new modules have arrived */
4319 if (dtv[0] != tls_dtv_generation) {
4320 wlock_acquire(rtld_bind_lock, &lockstate);
4321 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4323 if (to_copy > tls_max_index)
4324 to_copy = tls_max_index;
4325 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4326 newdtv[0] = tls_dtv_generation;
4327 newdtv[1] = tls_max_index;
4329 lock_release(rtld_bind_lock, &lockstate);
4330 dtv = *dtvp = newdtv;
4333 /* Dynamically allocate module TLS if necessary */
4334 if (dtv[index + 1] == 0) {
4335 /* Signal safe, wlock will block out signals. */
4336 wlock_acquire(rtld_bind_lock, &lockstate);
4337 if (!dtv[index + 1])
4338 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4339 lock_release(rtld_bind_lock, &lockstate);
4341 return ((void *)(dtv[index + 1] + offset));
4345 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4350 /* Check dtv generation in case new modules have arrived */
4351 if (__predict_true(dtv[0] == tls_dtv_generation &&
4352 dtv[index + 1] != 0))
4353 return ((void *)(dtv[index + 1] + offset));
4354 return (tls_get_addr_slow(dtvp, index, offset));
4357 #if defined(__arm__) || defined(__mips__) || defined(__powerpc__)
4360 * Allocate Static TLS using the Variant I method.
4363 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4372 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4375 assert(tcbsize >= TLS_TCB_SIZE);
4376 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4377 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4379 if (oldtcb != NULL) {
4380 memcpy(tls, oldtcb, tls_static_space);
4383 /* Adjust the DTV. */
4385 for (i = 0; i < dtv[1]; i++) {
4386 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4387 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4388 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4392 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4394 dtv[0] = tls_dtv_generation;
4395 dtv[1] = tls_max_index;
4397 for (obj = objs; obj; obj = obj->next) {
4398 if (obj->tlsoffset > 0) {
4399 addr = (Elf_Addr)tls + obj->tlsoffset;
4400 if (obj->tlsinitsize > 0)
4401 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4402 if (obj->tlssize > obj->tlsinitsize)
4403 memset((void*) (addr + obj->tlsinitsize), 0,
4404 obj->tlssize - obj->tlsinitsize);
4405 dtv[obj->tlsindex + 1] = addr;
4414 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4417 Elf_Addr tlsstart, tlsend;
4420 assert(tcbsize >= TLS_TCB_SIZE);
4422 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4423 tlsend = tlsstart + tls_static_space;
4425 dtv = *(Elf_Addr **)tlsstart;
4427 for (i = 0; i < dtvsize; i++) {
4428 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4429 free((void*)dtv[i+2]);
4438 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4441 * Allocate Static TLS using the Variant II method.
4444 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4447 size_t size, ralign;
4449 Elf_Addr *dtv, *olddtv;
4450 Elf_Addr segbase, oldsegbase, addr;
4454 if (tls_static_max_align > ralign)
4455 ralign = tls_static_max_align;
4456 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4458 assert(tcbsize >= 2*sizeof(Elf_Addr));
4459 tls = malloc_aligned(size, ralign);
4460 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4462 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4463 ((Elf_Addr*)segbase)[0] = segbase;
4464 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4466 dtv[0] = tls_dtv_generation;
4467 dtv[1] = tls_max_index;
4471 * Copy the static TLS block over whole.
4473 oldsegbase = (Elf_Addr) oldtls;
4474 memcpy((void *)(segbase - tls_static_space),
4475 (const void *)(oldsegbase - tls_static_space),
4479 * If any dynamic TLS blocks have been created tls_get_addr(),
4482 olddtv = ((Elf_Addr**)oldsegbase)[1];
4483 for (i = 0; i < olddtv[1]; i++) {
4484 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4485 dtv[i+2] = olddtv[i+2];
4491 * We assume that this block was the one we created with
4492 * allocate_initial_tls().
4494 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4496 for (obj = objs; obj; obj = obj->next) {
4497 if (obj->tlsoffset) {
4498 addr = segbase - obj->tlsoffset;
4499 memset((void*) (addr + obj->tlsinitsize),
4500 0, obj->tlssize - obj->tlsinitsize);
4502 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4503 dtv[obj->tlsindex + 1] = addr;
4508 return (void*) segbase;
4512 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4515 size_t size, ralign;
4517 Elf_Addr tlsstart, tlsend;
4520 * Figure out the size of the initial TLS block so that we can
4521 * find stuff which ___tls_get_addr() allocated dynamically.
4524 if (tls_static_max_align > ralign)
4525 ralign = tls_static_max_align;
4526 size = round(tls_static_space, ralign);
4528 dtv = ((Elf_Addr**)tls)[1];
4530 tlsend = (Elf_Addr) tls;
4531 tlsstart = tlsend - size;
4532 for (i = 0; i < dtvsize; i++) {
4533 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4534 free_aligned((void *)dtv[i + 2]);
4538 free_aligned((void *)tlsstart);
4545 * Allocate TLS block for module with given index.
4548 allocate_module_tls(int index)
4553 for (obj = obj_list; obj; obj = obj->next) {
4554 if (obj->tlsindex == index)
4558 _rtld_error("Can't find module with TLS index %d", index);
4562 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4563 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4564 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4570 allocate_tls_offset(Obj_Entry *obj)
4577 if (obj->tlssize == 0) {
4578 obj->tls_done = true;
4582 if (obj->tlsindex == 1)
4583 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4585 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4586 obj->tlssize, obj->tlsalign);
4589 * If we have already fixed the size of the static TLS block, we
4590 * must stay within that size. When allocating the static TLS, we
4591 * leave a small amount of space spare to be used for dynamically
4592 * loading modules which use static TLS.
4594 if (tls_static_space != 0) {
4595 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4597 } else if (obj->tlsalign > tls_static_max_align) {
4598 tls_static_max_align = obj->tlsalign;
4601 tls_last_offset = obj->tlsoffset = off;
4602 tls_last_size = obj->tlssize;
4603 obj->tls_done = true;
4609 free_tls_offset(Obj_Entry *obj)
4613 * If we were the last thing to allocate out of the static TLS
4614 * block, we give our space back to the 'allocator'. This is a
4615 * simplistic workaround to allow libGL.so.1 to be loaded and
4616 * unloaded multiple times.
4618 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4619 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4620 tls_last_offset -= obj->tlssize;
4626 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4629 RtldLockState lockstate;
4631 wlock_acquire(rtld_bind_lock, &lockstate);
4632 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4633 lock_release(rtld_bind_lock, &lockstate);
4638 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4640 RtldLockState lockstate;
4642 wlock_acquire(rtld_bind_lock, &lockstate);
4643 free_tls(tcb, tcbsize, tcbalign);
4644 lock_release(rtld_bind_lock, &lockstate);
4648 object_add_name(Obj_Entry *obj, const char *name)
4654 entry = malloc(sizeof(Name_Entry) + len);
4656 if (entry != NULL) {
4657 strcpy(entry->name, name);
4658 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4663 object_match_name(const Obj_Entry *obj, const char *name)
4667 STAILQ_FOREACH(entry, &obj->names, link) {
4668 if (strcmp(name, entry->name) == 0)
4675 locate_dependency(const Obj_Entry *obj, const char *name)
4677 const Objlist_Entry *entry;
4678 const Needed_Entry *needed;
4680 STAILQ_FOREACH(entry, &list_main, link) {
4681 if (object_match_name(entry->obj, name))
4685 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4686 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4687 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4689 * If there is DT_NEEDED for the name we are looking for,
4690 * we are all set. Note that object might not be found if
4691 * dependency was not loaded yet, so the function can
4692 * return NULL here. This is expected and handled
4693 * properly by the caller.
4695 return (needed->obj);
4698 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4704 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4705 const Elf_Vernaux *vna)
4707 const Elf_Verdef *vd;
4708 const char *vername;
4710 vername = refobj->strtab + vna->vna_name;
4711 vd = depobj->verdef;
4713 _rtld_error("%s: version %s required by %s not defined",
4714 depobj->path, vername, refobj->path);
4718 if (vd->vd_version != VER_DEF_CURRENT) {
4719 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4720 depobj->path, vd->vd_version);
4723 if (vna->vna_hash == vd->vd_hash) {
4724 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4725 ((char *)vd + vd->vd_aux);
4726 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4729 if (vd->vd_next == 0)
4731 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4733 if (vna->vna_flags & VER_FLG_WEAK)
4735 _rtld_error("%s: version %s required by %s not found",
4736 depobj->path, vername, refobj->path);
4741 rtld_verify_object_versions(Obj_Entry *obj)
4743 const Elf_Verneed *vn;
4744 const Elf_Verdef *vd;
4745 const Elf_Verdaux *vda;
4746 const Elf_Vernaux *vna;
4747 const Obj_Entry *depobj;
4748 int maxvernum, vernum;
4750 if (obj->ver_checked)
4752 obj->ver_checked = true;
4756 * Walk over defined and required version records and figure out
4757 * max index used by any of them. Do very basic sanity checking
4761 while (vn != NULL) {
4762 if (vn->vn_version != VER_NEED_CURRENT) {
4763 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4764 obj->path, vn->vn_version);
4767 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4769 vernum = VER_NEED_IDX(vna->vna_other);
4770 if (vernum > maxvernum)
4772 if (vna->vna_next == 0)
4774 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4776 if (vn->vn_next == 0)
4778 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4782 while (vd != NULL) {
4783 if (vd->vd_version != VER_DEF_CURRENT) {
4784 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4785 obj->path, vd->vd_version);
4788 vernum = VER_DEF_IDX(vd->vd_ndx);
4789 if (vernum > maxvernum)
4791 if (vd->vd_next == 0)
4793 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4800 * Store version information in array indexable by version index.
4801 * Verify that object version requirements are satisfied along the
4804 obj->vernum = maxvernum + 1;
4805 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4808 while (vd != NULL) {
4809 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4810 vernum = VER_DEF_IDX(vd->vd_ndx);
4811 assert(vernum <= maxvernum);
4812 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4813 obj->vertab[vernum].hash = vd->vd_hash;
4814 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4815 obj->vertab[vernum].file = NULL;
4816 obj->vertab[vernum].flags = 0;
4818 if (vd->vd_next == 0)
4820 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4824 while (vn != NULL) {
4825 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4828 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4830 if (check_object_provided_version(obj, depobj, vna))
4832 vernum = VER_NEED_IDX(vna->vna_other);
4833 assert(vernum <= maxvernum);
4834 obj->vertab[vernum].hash = vna->vna_hash;
4835 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4836 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4837 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4838 VER_INFO_HIDDEN : 0;
4839 if (vna->vna_next == 0)
4841 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4843 if (vn->vn_next == 0)
4845 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4851 rtld_verify_versions(const Objlist *objlist)
4853 Objlist_Entry *entry;
4857 STAILQ_FOREACH(entry, objlist, link) {
4859 * Skip dummy objects or objects that have their version requirements
4862 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4864 if (rtld_verify_object_versions(entry->obj) == -1) {
4866 if (ld_tracing == NULL)
4870 if (rc == 0 || ld_tracing != NULL)
4871 rc = rtld_verify_object_versions(&obj_rtld);
4876 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4881 vernum = VER_NDX(obj->versyms[symnum]);
4882 if (vernum >= obj->vernum) {
4883 _rtld_error("%s: symbol %s has wrong verneed value %d",
4884 obj->path, obj->strtab + symnum, vernum);
4885 } else if (obj->vertab[vernum].hash != 0) {
4886 return &obj->vertab[vernum];
4893 _rtld_get_stack_prot(void)
4896 return (stack_prot);
4900 _rtld_is_dlopened(void *arg)
4903 RtldLockState lockstate;
4906 rlock_acquire(rtld_bind_lock, &lockstate);
4909 obj = obj_from_addr(arg);
4911 _rtld_error("No shared object contains address");
4912 lock_release(rtld_bind_lock, &lockstate);
4915 res = obj->dlopened ? 1 : 0;
4916 lock_release(rtld_bind_lock, &lockstate);
4921 map_stacks_exec(RtldLockState *lockstate)
4923 void (*thr_map_stacks_exec)(void);
4925 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4927 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4928 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4929 if (thr_map_stacks_exec != NULL) {
4930 stack_prot |= PROT_EXEC;
4931 thr_map_stacks_exec();
4936 symlook_init(SymLook *dst, const char *name)
4939 bzero(dst, sizeof(*dst));
4941 dst->hash = elf_hash(name);
4942 dst->hash_gnu = gnu_hash(name);
4946 symlook_init_from_req(SymLook *dst, const SymLook *src)
4949 dst->name = src->name;
4950 dst->hash = src->hash;
4951 dst->hash_gnu = src->hash_gnu;
4952 dst->ventry = src->ventry;
4953 dst->flags = src->flags;
4954 dst->defobj_out = NULL;
4955 dst->sym_out = NULL;
4956 dst->lockstate = src->lockstate;
4961 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
4964 parse_libdir(const char *str)
4966 static const int RADIX = 10; /* XXXJA: possibly support hex? */
4973 for (c = *str; c != '\0'; c = *++str) {
4974 if (c < '0' || c > '9')
4981 /* Make sure we actually parsed something. */
4983 _rtld_error("failed to parse directory FD from '%s'", str);
4990 * Overrides for libc_pic-provided functions.
4994 __getosreldate(void)
5004 oid[1] = KERN_OSRELDATE;
5006 len = sizeof(osrel);
5007 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5008 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5020 void (*__cleanup)(void);
5021 int __isthreaded = 0;
5022 int _thread_autoinit_dummy_decl = 1;
5025 * No unresolved symbols for rtld.
5028 __pthread_cxa_finalize(struct dl_phdr_info *a)
5033 __stack_chk_fail(void)
5036 _rtld_error("stack overflow detected; terminated");
5039 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5045 _rtld_error("buffer overflow detected; terminated");
5050 rtld_strerror(int errnum)
5053 if (errnum < 0 || errnum >= sys_nerr)
5054 return ("Unknown error");
5055 return (sys_errlist[errnum]);