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 *);
98 static const char *gethints(bool);
99 static void init_dag(Obj_Entry *);
100 static void init_rtld(caddr_t, Elf_Auxinfo **);
101 static void initlist_add_neededs(Needed_Entry *, Objlist *);
102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
103 static void linkmap_add(Obj_Entry *);
104 static void linkmap_delete(Obj_Entry *);
105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
106 static void unload_filtees(Obj_Entry *);
107 static int load_needed_objects(Obj_Entry *, int);
108 static int load_preload_objects(void);
109 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
110 static void map_stacks_exec(RtldLockState *);
111 static Obj_Entry *obj_from_addr(const void *);
112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
113 static void objlist_call_init(Objlist *, RtldLockState *);
114 static void objlist_clear(Objlist *);
115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
116 static void objlist_init(Objlist *);
117 static void objlist_push_head(Objlist *, Obj_Entry *);
118 static void objlist_push_tail(Objlist *, Obj_Entry *);
119 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
120 static void objlist_remove(Objlist *, Obj_Entry *);
121 static void *path_enumerate(const char *, path_enum_proc, void *);
122 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
123 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
124 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
125 int flags, RtldLockState *lockstate);
126 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
128 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
129 int flags, RtldLockState *lockstate);
130 static int rtld_dirname(const char *, char *);
131 static int rtld_dirname_abs(const char *, char *);
132 static void *rtld_dlopen(const char *name, int fd, int mode);
133 static void rtld_exit(void);
134 static char *search_library_path(const char *, const char *);
135 static const void **get_program_var_addr(const char *, RtldLockState *);
136 static void set_program_var(const char *, const void *);
137 static int symlook_default(SymLook *, const Obj_Entry *refobj);
138 static int symlook_global(SymLook *, DoneList *);
139 static void symlook_init_from_req(SymLook *, const SymLook *);
140 static int symlook_list(SymLook *, const Objlist *, DoneList *);
141 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
142 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
143 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
144 static void trace_loaded_objects(Obj_Entry *);
145 static void unlink_object(Obj_Entry *);
146 static void unload_object(Obj_Entry *);
147 static void unref_dag(Obj_Entry *);
148 static void ref_dag(Obj_Entry *);
149 static char *origin_subst_one(char *, const char *, const char *, bool);
150 static char *origin_subst(char *, const char *);
151 static void preinit_main(void);
152 static int rtld_verify_versions(const Objlist *);
153 static int rtld_verify_object_versions(Obj_Entry *);
154 static void object_add_name(Obj_Entry *, const char *);
155 static int object_match_name(const Obj_Entry *, const char *);
156 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
157 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
158 struct dl_phdr_info *phdr_info);
159 static uint32_t gnu_hash(const char *);
160 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
161 const unsigned long);
163 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
164 void _r_debug_postinit(struct link_map *) __noinline;
169 static char *error_message; /* Message for dlerror(), or NULL */
170 struct r_debug r_debug; /* for GDB; */
171 static bool libmap_disable; /* Disable libmap */
172 static bool ld_loadfltr; /* Immediate filters processing */
173 static char *libmap_override; /* Maps to use in addition to libmap.conf */
174 static bool trust; /* False for setuid and setgid programs */
175 static bool dangerous_ld_env; /* True if environment variables have been
176 used to affect the libraries loaded */
177 static char *ld_bind_now; /* Environment variable for immediate binding */
178 static char *ld_debug; /* Environment variable for debugging */
179 static char *ld_library_path; /* Environment variable for search path */
180 static char *ld_preload; /* Environment variable for libraries to
182 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
183 static char *ld_tracing; /* Called from ldd to print libs */
184 static char *ld_utrace; /* Use utrace() to log events. */
185 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
186 static Obj_Entry **obj_tail; /* Link field of last object in list */
187 static Obj_Entry *obj_main; /* The main program shared object */
188 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
189 static unsigned int obj_count; /* Number of objects in obj_list */
190 static unsigned int obj_loads; /* Number of objects in obj_list */
192 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
193 STAILQ_HEAD_INITIALIZER(list_global);
194 static Objlist list_main = /* Objects loaded at program startup */
195 STAILQ_HEAD_INITIALIZER(list_main);
196 static Objlist list_fini = /* Objects needing fini() calls */
197 STAILQ_HEAD_INITIALIZER(list_fini);
199 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
201 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
203 extern Elf_Dyn _DYNAMIC;
204 #pragma weak _DYNAMIC
205 #ifndef RTLD_IS_DYNAMIC
206 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
209 int osreldate, pagesize;
211 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
213 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
214 static int max_stack_flags;
217 * Global declarations normally provided by crt1. The dynamic linker is
218 * not built with crt1, so we have to provide them ourselves.
224 * Used to pass argc, argv to init functions.
230 * Globals to control TLS allocation.
232 size_t tls_last_offset; /* Static TLS offset of last module */
233 size_t tls_last_size; /* Static TLS size of last module */
234 size_t tls_static_space; /* Static TLS space allocated */
235 size_t tls_static_max_align;
236 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
237 int tls_max_index = 1; /* Largest module index allocated */
239 bool ld_library_path_rpath = true;
242 * Fill in a DoneList with an allocation large enough to hold all of
243 * the currently-loaded objects. Keep this as a macro since it calls
244 * alloca and we want that to occur within the scope of the caller.
246 #define donelist_init(dlp) \
247 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
248 assert((dlp)->objs != NULL), \
249 (dlp)->num_alloc = obj_count, \
252 #define UTRACE_DLOPEN_START 1
253 #define UTRACE_DLOPEN_STOP 2
254 #define UTRACE_DLCLOSE_START 3
255 #define UTRACE_DLCLOSE_STOP 4
256 #define UTRACE_LOAD_OBJECT 5
257 #define UTRACE_UNLOAD_OBJECT 6
258 #define UTRACE_ADD_RUNDEP 7
259 #define UTRACE_PRELOAD_FINISHED 8
260 #define UTRACE_INIT_CALL 9
261 #define UTRACE_FINI_CALL 10
264 char sig[4]; /* 'RTLD' */
267 void *mapbase; /* Used for 'parent' and 'init/fini' */
269 int refcnt; /* Used for 'mode' */
270 char name[MAXPATHLEN];
273 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
274 if (ld_utrace != NULL) \
275 ld_utrace_log(e, h, mb, ms, r, n); \
279 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
280 int refcnt, const char *name)
282 struct utrace_rtld ut;
290 ut.mapbase = mapbase;
291 ut.mapsize = mapsize;
293 bzero(ut.name, sizeof(ut.name));
295 strlcpy(ut.name, name, sizeof(ut.name));
296 utrace(&ut, sizeof(ut));
300 * Main entry point for dynamic linking. The first argument is the
301 * stack pointer. The stack is expected to be laid out as described
302 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
303 * Specifically, the stack pointer points to a word containing
304 * ARGC. Following that in the stack is a null-terminated sequence
305 * of pointers to argument strings. Then comes a null-terminated
306 * sequence of pointers to environment strings. Finally, there is a
307 * sequence of "auxiliary vector" entries.
309 * The second argument points to a place to store the dynamic linker's
310 * exit procedure pointer and the third to a place to store the main
313 * The return value is the main program's entry point.
316 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
318 Elf_Auxinfo *aux_info[AT_COUNT];
326 Objlist_Entry *entry;
328 Obj_Entry **preload_tail;
329 Obj_Entry *last_interposer;
331 RtldLockState lockstate;
332 char *library_path_rpath;
337 * On entry, the dynamic linker itself has not been relocated yet.
338 * Be very careful not to reference any global data until after
339 * init_rtld has returned. It is OK to reference file-scope statics
340 * and string constants, and to call static and global functions.
343 /* Find the auxiliary vector on the stack. */
346 sp += argc + 1; /* Skip over arguments and NULL terminator */
348 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
350 aux = (Elf_Auxinfo *) sp;
352 /* Digest the auxiliary vector. */
353 for (i = 0; i < AT_COUNT; i++)
355 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
356 if (auxp->a_type < AT_COUNT)
357 aux_info[auxp->a_type] = auxp;
360 /* Initialize and relocate ourselves. */
361 assert(aux_info[AT_BASE] != NULL);
362 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
364 __progname = obj_rtld.path;
365 argv0 = argv[0] != NULL ? argv[0] : "(null)";
370 if (aux_info[AT_CANARY] != NULL &&
371 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
372 i = aux_info[AT_CANARYLEN]->a_un.a_val;
373 if (i > sizeof(__stack_chk_guard))
374 i = sizeof(__stack_chk_guard);
375 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
380 len = sizeof(__stack_chk_guard);
381 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
382 len != sizeof(__stack_chk_guard)) {
383 /* If sysctl was unsuccessful, use the "terminator canary". */
384 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
385 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
386 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
387 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
391 trust = !issetugid();
393 ld_bind_now = getenv(LD_ "BIND_NOW");
395 * If the process is tainted, then we un-set the dangerous environment
396 * variables. The process will be marked as tainted until setuid(2)
397 * is called. If any child process calls setuid(2) we do not want any
398 * future processes to honor the potentially un-safe variables.
401 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
402 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
403 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
404 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
405 _rtld_error("environment corrupt; aborting");
409 ld_debug = getenv(LD_ "DEBUG");
410 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
411 libmap_override = getenv(LD_ "LIBMAP");
412 ld_library_path = getenv(LD_ "LIBRARY_PATH");
413 ld_preload = getenv(LD_ "PRELOAD");
414 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
415 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
416 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
417 if (library_path_rpath != NULL) {
418 if (library_path_rpath[0] == 'y' ||
419 library_path_rpath[0] == 'Y' ||
420 library_path_rpath[0] == '1')
421 ld_library_path_rpath = true;
423 ld_library_path_rpath = false;
425 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
426 (ld_library_path != NULL) || (ld_preload != NULL) ||
427 (ld_elf_hints_path != NULL) || ld_loadfltr;
428 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
429 ld_utrace = getenv(LD_ "UTRACE");
431 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
432 ld_elf_hints_path = _PATH_ELF_HINTS;
434 if (ld_debug != NULL && *ld_debug != '\0')
436 dbg("%s is initialized, base address = %p", __progname,
437 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
438 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
439 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
441 dbg("initializing thread locks");
445 * Load the main program, or process its program header if it is
448 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
449 int fd = aux_info[AT_EXECFD]->a_un.a_val;
450 dbg("loading main program");
451 obj_main = map_object(fd, argv0, NULL);
453 if (obj_main == NULL)
455 max_stack_flags = obj->stack_flags;
456 } else { /* Main program already loaded. */
457 const Elf_Phdr *phdr;
461 dbg("processing main program's program header");
462 assert(aux_info[AT_PHDR] != NULL);
463 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
464 assert(aux_info[AT_PHNUM] != NULL);
465 phnum = aux_info[AT_PHNUM]->a_un.a_val;
466 assert(aux_info[AT_PHENT] != NULL);
467 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
468 assert(aux_info[AT_ENTRY] != NULL);
469 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
470 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
474 if (aux_info[AT_EXECPATH] != 0) {
476 char buf[MAXPATHLEN];
478 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
479 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
480 if (kexecpath[0] == '/')
481 obj_main->path = kexecpath;
482 else if (getcwd(buf, sizeof(buf)) == NULL ||
483 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
484 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
485 obj_main->path = xstrdup(argv0);
487 obj_main->path = xstrdup(buf);
489 dbg("No AT_EXECPATH");
490 obj_main->path = xstrdup(argv0);
492 dbg("obj_main path %s", obj_main->path);
493 obj_main->mainprog = true;
495 if (aux_info[AT_STACKPROT] != NULL &&
496 aux_info[AT_STACKPROT]->a_un.a_val != 0)
497 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
500 * Get the actual dynamic linker pathname from the executable if
501 * possible. (It should always be possible.) That ensures that
502 * gdb will find the right dynamic linker even if a non-standard
505 if (obj_main->interp != NULL &&
506 strcmp(obj_main->interp, obj_rtld.path) != 0) {
508 obj_rtld.path = xstrdup(obj_main->interp);
509 __progname = obj_rtld.path;
512 digest_dynamic(obj_main, 0);
513 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
514 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
515 obj_main->dynsymcount);
517 linkmap_add(obj_main);
518 linkmap_add(&obj_rtld);
520 /* Link the main program into the list of objects. */
521 *obj_tail = obj_main;
522 obj_tail = &obj_main->next;
526 /* Initialize a fake symbol for resolving undefined weak references. */
527 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
528 sym_zero.st_shndx = SHN_UNDEF;
529 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
532 libmap_disable = (bool)lm_init(libmap_override);
534 dbg("loading LD_PRELOAD libraries");
535 if (load_preload_objects() == -1)
537 preload_tail = obj_tail;
539 dbg("loading needed objects");
540 if (load_needed_objects(obj_main, 0) == -1)
543 /* Make a list of all objects loaded at startup. */
544 last_interposer = obj_main;
545 for (obj = obj_list; obj != NULL; obj = obj->next) {
546 if (obj->z_interpose && obj != obj_main) {
547 objlist_put_after(&list_main, last_interposer, obj);
548 last_interposer = obj;
550 objlist_push_tail(&list_main, obj);
555 dbg("checking for required versions");
556 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
559 if (ld_tracing) { /* We're done */
560 trace_loaded_objects(obj_main);
564 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
565 dump_relocations(obj_main);
570 * Processing tls relocations requires having the tls offsets
571 * initialized. Prepare offsets before starting initial
572 * relocation processing.
574 dbg("initializing initial thread local storage offsets");
575 STAILQ_FOREACH(entry, &list_main, link) {
577 * Allocate all the initial objects out of the static TLS
578 * block even if they didn't ask for it.
580 allocate_tls_offset(entry->obj);
583 if (relocate_objects(obj_main,
584 ld_bind_now != NULL && *ld_bind_now != '\0',
585 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
588 dbg("doing copy relocations");
589 if (do_copy_relocations(obj_main) == -1)
592 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
593 dump_relocations(obj_main);
598 * Setup TLS for main thread. This must be done after the
599 * relocations are processed, since tls initialization section
600 * might be the subject for relocations.
602 dbg("initializing initial thread local storage");
603 allocate_initial_tls(obj_list);
605 dbg("initializing key program variables");
606 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
607 set_program_var("environ", env);
608 set_program_var("__elf_aux_vector", aux);
610 /* Make a list of init functions to call. */
611 objlist_init(&initlist);
612 initlist_add_objects(obj_list, preload_tail, &initlist);
614 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
616 map_stacks_exec(NULL);
618 dbg("resolving ifuncs");
619 if (resolve_objects_ifunc(obj_main,
620 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
624 if (!obj_main->crt_no_init) {
626 * Make sure we don't call the main program's init and fini
627 * functions for binaries linked with old crt1 which calls
630 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
631 obj_main->preinit_array = obj_main->init_array =
632 obj_main->fini_array = (Elf_Addr)NULL;
635 wlock_acquire(rtld_bind_lock, &lockstate);
636 if (obj_main->crt_no_init)
638 objlist_call_init(&initlist, &lockstate);
639 _r_debug_postinit(&obj_main->linkmap);
640 objlist_clear(&initlist);
641 dbg("loading filtees");
642 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
643 if (ld_loadfltr || obj->z_loadfltr)
644 load_filtees(obj, 0, &lockstate);
646 lock_release(rtld_bind_lock, &lockstate);
648 dbg("transferring control to program entry point = %p", obj_main->entry);
650 /* Return the exit procedure and the program entry point. */
651 *exit_proc = rtld_exit;
653 return (func_ptr_type) obj_main->entry;
657 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
662 ptr = (void *)make_function_pointer(def, obj);
663 target = ((Elf_Addr (*)(void))ptr)();
664 return ((void *)target);
668 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
672 const Obj_Entry *defobj;
675 RtldLockState lockstate;
677 rlock_acquire(rtld_bind_lock, &lockstate);
678 if (sigsetjmp(lockstate.env, 0) != 0)
679 lock_upgrade(rtld_bind_lock, &lockstate);
681 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
683 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
685 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
686 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
690 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
691 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
693 target = (Elf_Addr)(defobj->relocbase + def->st_value);
695 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
696 defobj->strtab + def->st_name, basename(obj->path),
697 (void *)target, basename(defobj->path));
700 * Write the new contents for the jmpslot. Note that depending on
701 * architecture, the value which we need to return back to the
702 * lazy binding trampoline may or may not be the target
703 * address. The value returned from reloc_jmpslot() is the value
704 * that the trampoline needs.
706 target = reloc_jmpslot(where, target, defobj, obj, rel);
707 lock_release(rtld_bind_lock, &lockstate);
712 * Error reporting function. Use it like printf. If formats the message
713 * into a buffer, and sets things up so that the next call to dlerror()
714 * will return the message.
717 _rtld_error(const char *fmt, ...)
719 static char buf[512];
723 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
729 * Return a dynamically-allocated copy of the current error message, if any.
734 return error_message == NULL ? NULL : xstrdup(error_message);
738 * Restore the current error message from a copy which was previously saved
739 * by errmsg_save(). The copy is freed.
742 errmsg_restore(char *saved_msg)
744 if (saved_msg == NULL)
745 error_message = NULL;
747 _rtld_error("%s", saved_msg);
753 basename(const char *name)
755 const char *p = strrchr(name, '/');
756 return p != NULL ? p + 1 : name;
759 static struct utsname uts;
762 origin_subst_one(char *real, const char *kw, const char *subst,
765 char *p, *p1, *res, *resp;
766 int subst_len, kw_len, subst_count, old_len, new_len;
771 * First, count the number of the keyword occurences, to
772 * preallocate the final string.
774 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
781 * If the keyword is not found, just return.
783 if (subst_count == 0)
784 return (may_free ? real : xstrdup(real));
787 * There is indeed something to substitute. Calculate the
788 * length of the resulting string, and allocate it.
790 subst_len = strlen(subst);
791 old_len = strlen(real);
792 new_len = old_len + (subst_len - kw_len) * subst_count;
793 res = xmalloc(new_len + 1);
796 * Now, execute the substitution loop.
798 for (p = real, resp = res, *resp = '\0';;) {
801 /* Copy the prefix before keyword. */
802 memcpy(resp, p, p1 - p);
804 /* Keyword replacement. */
805 memcpy(resp, subst, subst_len);
813 /* Copy to the end of string and finish. */
821 origin_subst(char *real, const char *origin_path)
823 char *res1, *res2, *res3, *res4;
825 if (uts.sysname[0] == '\0') {
826 if (uname(&uts) != 0) {
827 _rtld_error("utsname failed: %d", errno);
831 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
832 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
833 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
834 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
841 const char *msg = dlerror();
845 rtld_fdputstr(STDERR_FILENO, msg);
846 rtld_fdputchar(STDERR_FILENO, '\n');
851 * Process a shared object's DYNAMIC section, and save the important
852 * information in its Obj_Entry structure.
855 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
856 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
859 Needed_Entry **needed_tail = &obj->needed;
860 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
861 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
862 const Elf_Hashelt *hashtab;
863 const Elf32_Word *hashval;
864 Elf32_Word bkt, nmaskwords;
867 int plttype = DT_REL;
873 obj->bind_now = false;
874 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
875 switch (dynp->d_tag) {
878 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
882 obj->relsize = dynp->d_un.d_val;
886 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
890 obj->pltrel = (const Elf_Rel *)
891 (obj->relocbase + dynp->d_un.d_ptr);
895 obj->pltrelsize = dynp->d_un.d_val;
899 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
903 obj->relasize = dynp->d_un.d_val;
907 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
911 plttype = dynp->d_un.d_val;
912 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
916 obj->symtab = (const Elf_Sym *)
917 (obj->relocbase + dynp->d_un.d_ptr);
921 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
925 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
929 obj->strsize = dynp->d_un.d_val;
933 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
938 obj->verneednum = dynp->d_un.d_val;
942 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
947 obj->verdefnum = dynp->d_un.d_val;
951 obj->versyms = (const Elf_Versym *)(obj->relocbase +
957 hashtab = (const Elf_Hashelt *)(obj->relocbase +
959 obj->nbuckets = hashtab[0];
960 obj->nchains = hashtab[1];
961 obj->buckets = hashtab + 2;
962 obj->chains = obj->buckets + obj->nbuckets;
963 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
964 obj->buckets != NULL;
970 hashtab = (const Elf_Hashelt *)(obj->relocbase +
972 obj->nbuckets_gnu = hashtab[0];
973 obj->symndx_gnu = hashtab[1];
974 nmaskwords = hashtab[2];
975 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
976 /* Number of bitmask words is required to be power of 2 */
977 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
978 obj->maskwords_bm_gnu = nmaskwords - 1;
979 obj->shift2_gnu = hashtab[3];
980 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
981 obj->buckets_gnu = hashtab + 4 + bloom_size32;
982 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
984 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
985 obj->buckets_gnu != NULL;
991 Needed_Entry *nep = NEW(Needed_Entry);
992 nep->name = dynp->d_un.d_val;
997 needed_tail = &nep->next;
1003 Needed_Entry *nep = NEW(Needed_Entry);
1004 nep->name = dynp->d_un.d_val;
1008 *needed_filtees_tail = nep;
1009 needed_filtees_tail = &nep->next;
1015 Needed_Entry *nep = NEW(Needed_Entry);
1016 nep->name = dynp->d_un.d_val;
1020 *needed_aux_filtees_tail = nep;
1021 needed_aux_filtees_tail = &nep->next;
1026 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1030 obj->textrel = true;
1034 obj->symbolic = true;
1039 * We have to wait until later to process this, because we
1040 * might not have gotten the address of the string table yet.
1050 *dyn_runpath = dynp;
1054 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1057 case DT_PREINIT_ARRAY:
1058 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1061 case DT_PREINIT_ARRAYSZ:
1062 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1066 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1069 case DT_INIT_ARRAYSZ:
1070 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1074 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1078 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1081 case DT_FINI_ARRAYSZ:
1082 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1086 * Don't process DT_DEBUG on MIPS as the dynamic section
1087 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1092 /* XXX - not implemented yet */
1094 dbg("Filling in DT_DEBUG entry");
1095 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1100 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1101 obj->z_origin = true;
1102 if (dynp->d_un.d_val & DF_SYMBOLIC)
1103 obj->symbolic = true;
1104 if (dynp->d_un.d_val & DF_TEXTREL)
1105 obj->textrel = true;
1106 if (dynp->d_un.d_val & DF_BIND_NOW)
1107 obj->bind_now = true;
1108 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1112 case DT_MIPS_LOCAL_GOTNO:
1113 obj->local_gotno = dynp->d_un.d_val;
1116 case DT_MIPS_SYMTABNO:
1117 obj->symtabno = dynp->d_un.d_val;
1120 case DT_MIPS_GOTSYM:
1121 obj->gotsym = dynp->d_un.d_val;
1124 case DT_MIPS_RLD_MAP:
1127 dbg("Filling in DT_DEBUG entry");
1128 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1134 if (dynp->d_un.d_val & DF_1_NOOPEN)
1135 obj->z_noopen = true;
1136 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1137 obj->z_origin = true;
1138 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1140 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1141 obj->bind_now = true;
1142 if (dynp->d_un.d_val & DF_1_NODELETE)
1143 obj->z_nodelete = true;
1144 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1145 obj->z_loadfltr = true;
1146 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1147 obj->z_interpose = true;
1148 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1149 obj->z_nodeflib = true;
1154 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1161 obj->traced = false;
1163 if (plttype == DT_RELA) {
1164 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1166 obj->pltrelasize = obj->pltrelsize;
1167 obj->pltrelsize = 0;
1170 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1171 if (obj->valid_hash_sysv)
1172 obj->dynsymcount = obj->nchains;
1173 else if (obj->valid_hash_gnu) {
1174 obj->dynsymcount = 0;
1175 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1176 if (obj->buckets_gnu[bkt] == 0)
1178 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1181 while ((*hashval++ & 1u) == 0);
1183 obj->dynsymcount += obj->symndx_gnu;
1188 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1189 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1192 if (obj->z_origin && obj->origin_path == NULL) {
1193 obj->origin_path = xmalloc(PATH_MAX);
1194 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1198 if (dyn_runpath != NULL) {
1199 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1201 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1203 else if (dyn_rpath != NULL) {
1204 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1206 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1209 if (dyn_soname != NULL)
1210 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1214 digest_dynamic(Obj_Entry *obj, int early)
1216 const Elf_Dyn *dyn_rpath;
1217 const Elf_Dyn *dyn_soname;
1218 const Elf_Dyn *dyn_runpath;
1220 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1221 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1225 * Process a shared object's program header. This is used only for the
1226 * main program, when the kernel has already loaded the main program
1227 * into memory before calling the dynamic linker. It creates and
1228 * returns an Obj_Entry structure.
1231 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1234 const Elf_Phdr *phlimit = phdr + phnum;
1236 Elf_Addr note_start, note_end;
1240 for (ph = phdr; ph < phlimit; ph++) {
1241 if (ph->p_type != PT_PHDR)
1245 obj->phsize = ph->p_memsz;
1246 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1250 obj->stack_flags = PF_X | PF_R | PF_W;
1252 for (ph = phdr; ph < phlimit; ph++) {
1253 switch (ph->p_type) {
1256 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1260 if (nsegs == 0) { /* First load segment */
1261 obj->vaddrbase = trunc_page(ph->p_vaddr);
1262 obj->mapbase = obj->vaddrbase + obj->relocbase;
1263 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1265 } else { /* Last load segment */
1266 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1273 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1278 obj->tlssize = ph->p_memsz;
1279 obj->tlsalign = ph->p_align;
1280 obj->tlsinitsize = ph->p_filesz;
1281 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1285 obj->stack_flags = ph->p_flags;
1289 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1290 obj->relro_size = round_page(ph->p_memsz);
1294 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1295 note_end = note_start + ph->p_filesz;
1296 digest_notes(obj, note_start, note_end);
1301 _rtld_error("%s: too few PT_LOAD segments", path);
1310 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1312 const Elf_Note *note;
1313 const char *note_name;
1316 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1317 note = (const Elf_Note *)((const char *)(note + 1) +
1318 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1319 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1320 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1321 note->n_descsz != sizeof(int32_t))
1323 if (note->n_type != ABI_NOTETYPE &&
1324 note->n_type != CRT_NOINIT_NOTETYPE)
1326 note_name = (const char *)(note + 1);
1327 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1328 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1330 switch (note->n_type) {
1332 /* FreeBSD osrel note */
1333 p = (uintptr_t)(note + 1);
1334 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1335 obj->osrel = *(const int32_t *)(p);
1336 dbg("note osrel %d", obj->osrel);
1338 case CRT_NOINIT_NOTETYPE:
1339 /* FreeBSD 'crt does not call init' note */
1340 obj->crt_no_init = true;
1341 dbg("note crt_no_init");
1348 dlcheck(void *handle)
1352 for (obj = obj_list; obj != NULL; obj = obj->next)
1353 if (obj == (Obj_Entry *) handle)
1356 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1357 _rtld_error("Invalid shared object handle %p", handle);
1364 * If the given object is already in the donelist, return true. Otherwise
1365 * add the object to the list and return false.
1368 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1372 for (i = 0; i < dlp->num_used; i++)
1373 if (dlp->objs[i] == obj)
1376 * Our donelist allocation should always be sufficient. But if
1377 * our threads locking isn't working properly, more shared objects
1378 * could have been loaded since we allocated the list. That should
1379 * never happen, but we'll handle it properly just in case it does.
1381 if (dlp->num_used < dlp->num_alloc)
1382 dlp->objs[dlp->num_used++] = obj;
1387 * Hash function for symbol table lookup. Don't even think about changing
1388 * this. It is specified by the System V ABI.
1391 elf_hash(const char *name)
1393 const unsigned char *p = (const unsigned char *) name;
1394 unsigned long h = 0;
1397 while (*p != '\0') {
1398 h = (h << 4) + *p++;
1399 if ((g = h & 0xf0000000) != 0)
1407 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1408 * unsigned in case it's implemented with a wider type.
1411 gnu_hash(const char *s)
1417 for (c = *s; c != '\0'; c = *++s)
1419 return (h & 0xffffffff);
1423 * Find the library with the given name, and return its full pathname.
1424 * The returned string is dynamically allocated. Generates an error
1425 * message and returns NULL if the library cannot be found.
1427 * If the second argument is non-NULL, then it refers to an already-
1428 * loaded shared object, whose library search path will be searched.
1430 * The search order is:
1431 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1432 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1434 * DT_RUNPATH in the referencing file
1435 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1437 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1439 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1442 find_library(const char *xname, const Obj_Entry *refobj)
1446 bool nodeflib, objgiven;
1448 objgiven = refobj != NULL;
1449 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1450 if (xname[0] != '/' && !trust) {
1451 _rtld_error("Absolute pathname required for shared object \"%s\"",
1455 if (objgiven && refobj->z_origin) {
1456 return (origin_subst(__DECONST(char *, xname),
1457 refobj->origin_path));
1459 return (xstrdup(xname));
1463 if (libmap_disable || !objgiven ||
1464 (name = lm_find(refobj->path, xname)) == NULL)
1465 name = (char *)xname;
1467 dbg(" Searching for \"%s\"", name);
1470 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1471 * back to pre-conforming behaviour if user requested so with
1472 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1475 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1476 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1478 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1479 (pathname = search_library_path(name, gethints(false))) != NULL ||
1480 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1483 nodeflib = objgiven ? refobj->z_nodeflib : false;
1485 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1486 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1487 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1488 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1490 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1491 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1492 (objgiven && !nodeflib &&
1493 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1497 if (objgiven && refobj->path != NULL) {
1498 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1499 name, basename(refobj->path));
1501 _rtld_error("Shared object \"%s\" not found", name);
1507 * Given a symbol number in a referencing object, find the corresponding
1508 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1509 * no definition was found. Returns a pointer to the Obj_Entry of the
1510 * defining object via the reference parameter DEFOBJ_OUT.
1513 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1514 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1515 RtldLockState *lockstate)
1519 const Obj_Entry *defobj;
1525 * If we have already found this symbol, get the information from
1528 if (symnum >= refobj->dynsymcount)
1529 return NULL; /* Bad object */
1530 if (cache != NULL && cache[symnum].sym != NULL) {
1531 *defobj_out = cache[symnum].obj;
1532 return cache[symnum].sym;
1535 ref = refobj->symtab + symnum;
1536 name = refobj->strtab + ref->st_name;
1541 * We don't have to do a full scale lookup if the symbol is local.
1542 * We know it will bind to the instance in this load module; to
1543 * which we already have a pointer (ie ref). By not doing a lookup,
1544 * we not only improve performance, but it also avoids unresolvable
1545 * symbols when local symbols are not in the hash table. This has
1546 * been seen with the ia64 toolchain.
1548 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1549 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1550 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1553 symlook_init(&req, name);
1555 req.ventry = fetch_ventry(refobj, symnum);
1556 req.lockstate = lockstate;
1557 res = symlook_default(&req, refobj);
1560 defobj = req.defobj_out;
1568 * If we found no definition and the reference is weak, treat the
1569 * symbol as having the value zero.
1571 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1577 *defobj_out = defobj;
1578 /* Record the information in the cache to avoid subsequent lookups. */
1579 if (cache != NULL) {
1580 cache[symnum].sym = def;
1581 cache[symnum].obj = defobj;
1584 if (refobj != &obj_rtld)
1585 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1591 * Return the search path from the ldconfig hints file, reading it if
1592 * necessary. If nostdlib is true, then the default search paths are
1593 * not added to result.
1595 * Returns NULL if there are problems with the hints file,
1596 * or if the search path there is empty.
1599 gethints(bool nostdlib)
1601 static char *hints, *filtered_path;
1602 struct elfhints_hdr hdr;
1603 struct fill_search_info_args sargs, hargs;
1604 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1605 struct dl_serpath *SLPpath, *hintpath;
1607 unsigned int SLPndx, hintndx, fndx, fcount;
1612 /* First call, read the hints file */
1613 if (hints == NULL) {
1614 /* Keep from trying again in case the hints file is bad. */
1617 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1619 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1620 hdr.magic != ELFHINTS_MAGIC ||
1625 p = xmalloc(hdr.dirlistlen + 1);
1626 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1627 read(fd, p, hdr.dirlistlen + 1) !=
1628 (ssize_t)hdr.dirlistlen + 1) {
1638 * If caller agreed to receive list which includes the default
1639 * paths, we are done. Otherwise, if we still did not
1640 * calculated filtered result, do it now.
1643 return (hints[0] != '\0' ? hints : NULL);
1644 if (filtered_path != NULL)
1648 * Obtain the list of all configured search paths, and the
1649 * list of the default paths.
1651 * First estimate the size of the results.
1653 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1655 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1658 sargs.request = RTLD_DI_SERINFOSIZE;
1659 sargs.serinfo = &smeta;
1660 hargs.request = RTLD_DI_SERINFOSIZE;
1661 hargs.serinfo = &hmeta;
1663 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1664 path_enumerate(p, fill_search_info, &hargs);
1666 SLPinfo = xmalloc(smeta.dls_size);
1667 hintinfo = xmalloc(hmeta.dls_size);
1670 * Next fetch both sets of paths.
1672 sargs.request = RTLD_DI_SERINFO;
1673 sargs.serinfo = SLPinfo;
1674 sargs.serpath = &SLPinfo->dls_serpath[0];
1675 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1677 hargs.request = RTLD_DI_SERINFO;
1678 hargs.serinfo = hintinfo;
1679 hargs.serpath = &hintinfo->dls_serpath[0];
1680 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1682 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1683 path_enumerate(p, fill_search_info, &hargs);
1686 * Now calculate the difference between two sets, by excluding
1687 * standard paths from the full set.
1691 filtered_path = xmalloc(hdr.dirlistlen + 1);
1692 hintpath = &hintinfo->dls_serpath[0];
1693 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1695 SLPpath = &SLPinfo->dls_serpath[0];
1697 * Check each standard path against current.
1699 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1700 /* matched, skip the path */
1701 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1709 * Not matched against any standard path, add the path
1710 * to result. Separate consequtive paths with ':'.
1713 filtered_path[fndx] = ':';
1717 flen = strlen(hintpath->dls_name);
1718 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1721 filtered_path[fndx] = '\0';
1727 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1731 init_dag(Obj_Entry *root)
1733 const Needed_Entry *needed;
1734 const Objlist_Entry *elm;
1737 if (root->dag_inited)
1739 donelist_init(&donelist);
1741 /* Root object belongs to own DAG. */
1742 objlist_push_tail(&root->dldags, root);
1743 objlist_push_tail(&root->dagmembers, root);
1744 donelist_check(&donelist, root);
1747 * Add dependencies of root object to DAG in breadth order
1748 * by exploiting the fact that each new object get added
1749 * to the tail of the dagmembers list.
1751 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1752 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1753 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1755 objlist_push_tail(&needed->obj->dldags, root);
1756 objlist_push_tail(&root->dagmembers, needed->obj);
1759 root->dag_inited = true;
1763 process_nodelete(Obj_Entry *root)
1765 const Objlist_Entry *elm;
1768 * Walk over object DAG and process every dependent object that
1769 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1770 * which then should have its reference upped separately.
1772 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1773 if (elm->obj != NULL && elm->obj->z_nodelete &&
1774 !elm->obj->ref_nodel) {
1775 dbg("obj %s nodelete", elm->obj->path);
1778 elm->obj->ref_nodel = true;
1783 * Initialize the dynamic linker. The argument is the address at which
1784 * the dynamic linker has been mapped into memory. The primary task of
1785 * this function is to relocate the dynamic linker.
1788 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1790 Obj_Entry objtmp; /* Temporary rtld object */
1791 const Elf_Dyn *dyn_rpath;
1792 const Elf_Dyn *dyn_soname;
1793 const Elf_Dyn *dyn_runpath;
1796 * Conjure up an Obj_Entry structure for the dynamic linker.
1798 * The "path" member can't be initialized yet because string constants
1799 * cannot yet be accessed. Below we will set it correctly.
1801 memset(&objtmp, 0, sizeof(objtmp));
1804 objtmp.mapbase = mapbase;
1806 objtmp.relocbase = mapbase;
1808 if (RTLD_IS_DYNAMIC()) {
1809 objtmp.dynamic = rtld_dynamic(&objtmp);
1810 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1811 assert(objtmp.needed == NULL);
1812 #if !defined(__mips__)
1813 /* MIPS has a bogus DT_TEXTREL. */
1814 assert(!objtmp.textrel);
1818 * Temporarily put the dynamic linker entry into the object list, so
1819 * that symbols can be found.
1822 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1825 /* Initialize the object list. */
1826 obj_tail = &obj_list;
1828 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1829 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1831 if (aux_info[AT_PAGESZ] != NULL)
1832 pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
1833 if (aux_info[AT_OSRELDATE] != NULL)
1834 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1836 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1838 /* Replace the path with a dynamically allocated copy. */
1839 obj_rtld.path = xstrdup(PATH_RTLD);
1841 r_debug.r_brk = r_debug_state;
1842 r_debug.r_state = RT_CONSISTENT;
1846 * Add the init functions from a needed object list (and its recursive
1847 * needed objects) to "list". This is not used directly; it is a helper
1848 * function for initlist_add_objects(). The write lock must be held
1849 * when this function is called.
1852 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1854 /* Recursively process the successor needed objects. */
1855 if (needed->next != NULL)
1856 initlist_add_neededs(needed->next, list);
1858 /* Process the current needed object. */
1859 if (needed->obj != NULL)
1860 initlist_add_objects(needed->obj, &needed->obj->next, list);
1864 * Scan all of the DAGs rooted in the range of objects from "obj" to
1865 * "tail" and add their init functions to "list". This recurses over
1866 * the DAGs and ensure the proper init ordering such that each object's
1867 * needed libraries are initialized before the object itself. At the
1868 * same time, this function adds the objects to the global finalization
1869 * list "list_fini" in the opposite order. The write lock must be
1870 * held when this function is called.
1873 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1876 if (obj->init_scanned || obj->init_done)
1878 obj->init_scanned = true;
1880 /* Recursively process the successor objects. */
1881 if (&obj->next != tail)
1882 initlist_add_objects(obj->next, tail, list);
1884 /* Recursively process the needed objects. */
1885 if (obj->needed != NULL)
1886 initlist_add_neededs(obj->needed, list);
1887 if (obj->needed_filtees != NULL)
1888 initlist_add_neededs(obj->needed_filtees, list);
1889 if (obj->needed_aux_filtees != NULL)
1890 initlist_add_neededs(obj->needed_aux_filtees, list);
1892 /* Add the object to the init list. */
1893 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1894 obj->init_array != (Elf_Addr)NULL)
1895 objlist_push_tail(list, obj);
1897 /* Add the object to the global fini list in the reverse order. */
1898 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1899 && !obj->on_fini_list) {
1900 objlist_push_head(&list_fini, obj);
1901 obj->on_fini_list = true;
1906 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1910 free_needed_filtees(Needed_Entry *n)
1912 Needed_Entry *needed, *needed1;
1914 for (needed = n; needed != NULL; needed = needed->next) {
1915 if (needed->obj != NULL) {
1916 dlclose(needed->obj);
1920 for (needed = n; needed != NULL; needed = needed1) {
1921 needed1 = needed->next;
1927 unload_filtees(Obj_Entry *obj)
1930 free_needed_filtees(obj->needed_filtees);
1931 obj->needed_filtees = NULL;
1932 free_needed_filtees(obj->needed_aux_filtees);
1933 obj->needed_aux_filtees = NULL;
1934 obj->filtees_loaded = false;
1938 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
1939 RtldLockState *lockstate)
1942 for (; needed != NULL; needed = needed->next) {
1943 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1944 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1945 RTLD_LOCAL, lockstate);
1950 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1953 lock_restart_for_upgrade(lockstate);
1954 if (!obj->filtees_loaded) {
1955 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
1956 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
1957 obj->filtees_loaded = true;
1962 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1966 for (; needed != NULL; needed = needed->next) {
1967 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
1968 flags & ~RTLD_LO_NOLOAD);
1969 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1976 * Given a shared object, traverse its list of needed objects, and load
1977 * each of them. Returns 0 on success. Generates an error message and
1978 * returns -1 on failure.
1981 load_needed_objects(Obj_Entry *first, int flags)
1985 for (obj = first; obj != NULL; obj = obj->next) {
1986 if (process_needed(obj, obj->needed, flags) == -1)
1993 load_preload_objects(void)
1995 char *p = ld_preload;
1997 static const char delim[] = " \t:;";
2002 p += strspn(p, delim);
2003 while (*p != '\0') {
2004 size_t len = strcspn(p, delim);
2009 obj = load_object(p, -1, NULL, 0);
2011 return -1; /* XXX - cleanup */
2012 obj->z_interpose = true;
2015 p += strspn(p, delim);
2017 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2022 printable_path(const char *path)
2025 return (path == NULL ? "<unknown>" : path);
2029 * Load a shared object into memory, if it is not already loaded. The
2030 * object may be specified by name or by user-supplied file descriptor
2031 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2034 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2038 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2046 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2047 if (object_match_name(obj, name))
2051 path = find_library(name, refobj);
2058 * If we didn't find a match by pathname, or the name is not
2059 * supplied, open the file and check again by device and inode.
2060 * This avoids false mismatches caused by multiple links or ".."
2063 * To avoid a race, we open the file and use fstat() rather than
2068 if ((fd = open(path, O_RDONLY)) == -1) {
2069 _rtld_error("Cannot open \"%s\"", path);
2076 _rtld_error("Cannot dup fd");
2081 if (fstat(fd, &sb) == -1) {
2082 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2087 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2088 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2090 if (obj != NULL && name != NULL) {
2091 object_add_name(obj, name);
2096 if (flags & RTLD_LO_NOLOAD) {
2102 /* First use of this object, so we must map it in */
2103 obj = do_load_object(fd, name, path, &sb, flags);
2112 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2119 * but first, make sure that environment variables haven't been
2120 * used to circumvent the noexec flag on a filesystem.
2122 if (dangerous_ld_env) {
2123 if (fstatfs(fd, &fs) != 0) {
2124 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2127 if (fs.f_flags & MNT_NOEXEC) {
2128 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2132 dbg("loading \"%s\"", printable_path(path));
2133 obj = map_object(fd, printable_path(path), sbp);
2138 * If DT_SONAME is present in the object, digest_dynamic2 already
2139 * added it to the object names.
2142 object_add_name(obj, name);
2144 digest_dynamic(obj, 0);
2145 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2146 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2147 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2149 dbg("refusing to load non-loadable \"%s\"", obj->path);
2150 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2151 munmap(obj->mapbase, obj->mapsize);
2157 obj_tail = &obj->next;
2160 linkmap_add(obj); /* for GDB & dlinfo() */
2161 max_stack_flags |= obj->stack_flags;
2163 dbg(" %p .. %p: %s", obj->mapbase,
2164 obj->mapbase + obj->mapsize - 1, obj->path);
2166 dbg(" WARNING: %s has impure text", obj->path);
2167 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2174 obj_from_addr(const void *addr)
2178 for (obj = obj_list; obj != NULL; obj = obj->next) {
2179 if (addr < (void *) obj->mapbase)
2181 if (addr < (void *) (obj->mapbase + obj->mapsize))
2190 Elf_Addr *preinit_addr;
2193 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2194 if (preinit_addr == NULL)
2197 for (index = 0; index < obj_main->preinit_array_num; index++) {
2198 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2199 dbg("calling preinit function for %s at %p", obj_main->path,
2200 (void *)preinit_addr[index]);
2201 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2202 0, 0, obj_main->path);
2203 call_init_pointer(obj_main, preinit_addr[index]);
2209 * Call the finalization functions for each of the objects in "list"
2210 * belonging to the DAG of "root" and referenced once. If NULL "root"
2211 * is specified, every finalization function will be called regardless
2212 * of the reference count and the list elements won't be freed. All of
2213 * the objects are expected to have non-NULL fini functions.
2216 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2220 Elf_Addr *fini_addr;
2223 assert(root == NULL || root->refcount == 1);
2226 * Preserve the current error message since a fini function might
2227 * call into the dynamic linker and overwrite it.
2229 saved_msg = errmsg_save();
2231 STAILQ_FOREACH(elm, list, link) {
2232 if (root != NULL && (elm->obj->refcount != 1 ||
2233 objlist_find(&root->dagmembers, elm->obj) == NULL))
2235 /* Remove object from fini list to prevent recursive invocation. */
2236 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2238 * XXX: If a dlopen() call references an object while the
2239 * fini function is in progress, we might end up trying to
2240 * unload the referenced object in dlclose() or the object
2241 * won't be unloaded although its fini function has been
2244 lock_release(rtld_bind_lock, lockstate);
2247 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2248 * When this happens, DT_FINI_ARRAY is processed first.
2250 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2251 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2252 for (index = elm->obj->fini_array_num - 1; index >= 0;
2254 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2255 dbg("calling fini function for %s at %p",
2256 elm->obj->path, (void *)fini_addr[index]);
2257 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2258 (void *)fini_addr[index], 0, 0, elm->obj->path);
2259 call_initfini_pointer(elm->obj, fini_addr[index]);
2263 if (elm->obj->fini != (Elf_Addr)NULL) {
2264 dbg("calling fini function for %s at %p", elm->obj->path,
2265 (void *)elm->obj->fini);
2266 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2267 0, 0, elm->obj->path);
2268 call_initfini_pointer(elm->obj, elm->obj->fini);
2270 wlock_acquire(rtld_bind_lock, lockstate);
2271 /* No need to free anything if process is going down. */
2275 * We must restart the list traversal after every fini call
2276 * because a dlclose() call from the fini function or from
2277 * another thread might have modified the reference counts.
2281 } while (elm != NULL);
2282 errmsg_restore(saved_msg);
2286 * Call the initialization functions for each of the objects in
2287 * "list". All of the objects are expected to have non-NULL init
2291 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2296 Elf_Addr *init_addr;
2300 * Clean init_scanned flag so that objects can be rechecked and
2301 * possibly initialized earlier if any of vectors called below
2302 * cause the change by using dlopen.
2304 for (obj = obj_list; obj != NULL; obj = obj->next)
2305 obj->init_scanned = false;
2308 * Preserve the current error message since an init function might
2309 * call into the dynamic linker and overwrite it.
2311 saved_msg = errmsg_save();
2312 STAILQ_FOREACH(elm, list, link) {
2313 if (elm->obj->init_done) /* Initialized early. */
2316 * Race: other thread might try to use this object before current
2317 * one completes the initilization. Not much can be done here
2318 * without better locking.
2320 elm->obj->init_done = true;
2321 lock_release(rtld_bind_lock, lockstate);
2324 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2325 * When this happens, DT_INIT is processed first.
2327 if (elm->obj->init != (Elf_Addr)NULL) {
2328 dbg("calling init function for %s at %p", elm->obj->path,
2329 (void *)elm->obj->init);
2330 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2331 0, 0, elm->obj->path);
2332 call_initfini_pointer(elm->obj, elm->obj->init);
2334 init_addr = (Elf_Addr *)elm->obj->init_array;
2335 if (init_addr != NULL) {
2336 for (index = 0; index < elm->obj->init_array_num; index++) {
2337 if (init_addr[index] != 0 && init_addr[index] != 1) {
2338 dbg("calling init function for %s at %p", elm->obj->path,
2339 (void *)init_addr[index]);
2340 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2341 (void *)init_addr[index], 0, 0, elm->obj->path);
2342 call_init_pointer(elm->obj, init_addr[index]);
2346 wlock_acquire(rtld_bind_lock, lockstate);
2348 errmsg_restore(saved_msg);
2352 objlist_clear(Objlist *list)
2356 while (!STAILQ_EMPTY(list)) {
2357 elm = STAILQ_FIRST(list);
2358 STAILQ_REMOVE_HEAD(list, link);
2363 static Objlist_Entry *
2364 objlist_find(Objlist *list, const Obj_Entry *obj)
2368 STAILQ_FOREACH(elm, list, link)
2369 if (elm->obj == obj)
2375 objlist_init(Objlist *list)
2381 objlist_push_head(Objlist *list, Obj_Entry *obj)
2385 elm = NEW(Objlist_Entry);
2387 STAILQ_INSERT_HEAD(list, elm, link);
2391 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2395 elm = NEW(Objlist_Entry);
2397 STAILQ_INSERT_TAIL(list, elm, link);
2401 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2403 Objlist_Entry *elm, *listelm;
2405 STAILQ_FOREACH(listelm, list, link) {
2406 if (listelm->obj == listobj)
2409 elm = NEW(Objlist_Entry);
2411 if (listelm != NULL)
2412 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2414 STAILQ_INSERT_TAIL(list, elm, link);
2418 objlist_remove(Objlist *list, Obj_Entry *obj)
2422 if ((elm = objlist_find(list, obj)) != NULL) {
2423 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2429 * Relocate dag rooted in the specified object.
2430 * Returns 0 on success, or -1 on failure.
2434 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2435 int flags, RtldLockState *lockstate)
2441 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2442 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2451 * Relocate single object.
2452 * Returns 0 on success, or -1 on failure.
2455 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2456 int flags, RtldLockState *lockstate)
2461 obj->relocated = true;
2463 dbg("relocating \"%s\"", obj->path);
2465 if (obj->symtab == NULL || obj->strtab == NULL ||
2466 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2467 _rtld_error("%s: Shared object has no run-time symbol table",
2473 /* There are relocations to the write-protected text segment. */
2474 if (mprotect(obj->mapbase, obj->textsize,
2475 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2476 _rtld_error("%s: Cannot write-enable text segment: %s",
2477 obj->path, rtld_strerror(errno));
2482 /* Process the non-PLT relocations. */
2483 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2486 if (obj->textrel) { /* Re-protected the text segment. */
2487 if (mprotect(obj->mapbase, obj->textsize,
2488 PROT_READ|PROT_EXEC) == -1) {
2489 _rtld_error("%s: Cannot write-protect text segment: %s",
2490 obj->path, rtld_strerror(errno));
2496 /* Set the special PLT or GOT entries. */
2499 /* Process the PLT relocations. */
2500 if (reloc_plt(obj) == -1)
2502 /* Relocate the jump slots if we are doing immediate binding. */
2503 if (obj->bind_now || bind_now)
2504 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2507 if (obj->relro_size > 0) {
2508 if (mprotect(obj->relro_page, obj->relro_size,
2510 _rtld_error("%s: Cannot enforce relro protection: %s",
2511 obj->path, rtld_strerror(errno));
2517 * Set up the magic number and version in the Obj_Entry. These
2518 * were checked in the crt1.o from the original ElfKit, so we
2519 * set them for backward compatibility.
2521 obj->magic = RTLD_MAGIC;
2522 obj->version = RTLD_VERSION;
2528 * Relocate newly-loaded shared objects. The argument is a pointer to
2529 * the Obj_Entry for the first such object. All objects from the first
2530 * to the end of the list of objects are relocated. Returns 0 on success,
2534 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2535 int flags, RtldLockState *lockstate)
2540 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2541 error = relocate_object(obj, bind_now, rtldobj, flags,
2550 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2551 * referencing STT_GNU_IFUNC symbols is postponed till the other
2552 * relocations are done. The indirect functions specified as
2553 * ifunc are allowed to call other symbols, so we need to have
2554 * objects relocated before asking for resolution from indirects.
2556 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2557 * instead of the usual lazy handling of PLT slots. It is
2558 * consistent with how GNU does it.
2561 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2562 RtldLockState *lockstate)
2564 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2566 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2567 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2573 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2574 RtldLockState *lockstate)
2578 for (obj = first; obj != NULL; obj = obj->next) {
2579 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2586 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2587 RtldLockState *lockstate)
2591 STAILQ_FOREACH(elm, list, link) {
2592 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2600 * Cleanup procedure. It will be called (by the atexit mechanism) just
2601 * before the process exits.
2606 RtldLockState lockstate;
2608 wlock_acquire(rtld_bind_lock, &lockstate);
2610 objlist_call_fini(&list_fini, NULL, &lockstate);
2611 /* No need to remove the items from the list, since we are exiting. */
2612 if (!libmap_disable)
2614 lock_release(rtld_bind_lock, &lockstate);
2618 * Iterate over a search path, translate each element, and invoke the
2619 * callback on the result.
2622 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2628 path += strspn(path, ":;");
2629 while (*path != '\0') {
2633 len = strcspn(path, ":;");
2634 trans = lm_findn(NULL, path, len);
2636 res = callback(trans, strlen(trans), arg);
2638 res = callback(path, len, arg);
2644 path += strspn(path, ":;");
2650 struct try_library_args {
2658 try_library_path(const char *dir, size_t dirlen, void *param)
2660 struct try_library_args *arg;
2663 if (*dir == '/' || trust) {
2666 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2669 pathname = arg->buffer;
2670 strncpy(pathname, dir, dirlen);
2671 pathname[dirlen] = '/';
2672 strcpy(pathname + dirlen + 1, arg->name);
2674 dbg(" Trying \"%s\"", pathname);
2675 if (access(pathname, F_OK) == 0) { /* We found it */
2676 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2677 strcpy(pathname, arg->buffer);
2685 search_library_path(const char *name, const char *path)
2688 struct try_library_args arg;
2694 arg.namelen = strlen(name);
2695 arg.buffer = xmalloc(PATH_MAX);
2696 arg.buflen = PATH_MAX;
2698 p = path_enumerate(path, try_library_path, &arg);
2706 dlclose(void *handle)
2709 RtldLockState lockstate;
2711 wlock_acquire(rtld_bind_lock, &lockstate);
2712 root = dlcheck(handle);
2714 lock_release(rtld_bind_lock, &lockstate);
2717 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2720 /* Unreference the object and its dependencies. */
2721 root->dl_refcount--;
2723 if (root->refcount == 1) {
2725 * The object will be no longer referenced, so we must unload it.
2726 * First, call the fini functions.
2728 objlist_call_fini(&list_fini, root, &lockstate);
2732 /* Finish cleaning up the newly-unreferenced objects. */
2733 GDB_STATE(RT_DELETE,&root->linkmap);
2734 unload_object(root);
2735 GDB_STATE(RT_CONSISTENT,NULL);
2739 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2740 lock_release(rtld_bind_lock, &lockstate);
2747 char *msg = error_message;
2748 error_message = NULL;
2753 * This function is deprecated and has no effect.
2756 dllockinit(void *context,
2757 void *(*lock_create)(void *context),
2758 void (*rlock_acquire)(void *lock),
2759 void (*wlock_acquire)(void *lock),
2760 void (*lock_release)(void *lock),
2761 void (*lock_destroy)(void *lock),
2762 void (*context_destroy)(void *context))
2764 static void *cur_context;
2765 static void (*cur_context_destroy)(void *);
2767 /* Just destroy the context from the previous call, if necessary. */
2768 if (cur_context_destroy != NULL)
2769 cur_context_destroy(cur_context);
2770 cur_context = context;
2771 cur_context_destroy = context_destroy;
2775 dlopen(const char *name, int mode)
2778 return (rtld_dlopen(name, -1, mode));
2782 fdlopen(int fd, int mode)
2785 return (rtld_dlopen(NULL, fd, mode));
2789 rtld_dlopen(const char *name, int fd, int mode)
2791 RtldLockState lockstate;
2794 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2795 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2796 if (ld_tracing != NULL) {
2797 rlock_acquire(rtld_bind_lock, &lockstate);
2798 if (sigsetjmp(lockstate.env, 0) != 0)
2799 lock_upgrade(rtld_bind_lock, &lockstate);
2800 environ = (char **)*get_program_var_addr("environ", &lockstate);
2801 lock_release(rtld_bind_lock, &lockstate);
2803 lo_flags = RTLD_LO_DLOPEN;
2804 if (mode & RTLD_NODELETE)
2805 lo_flags |= RTLD_LO_NODELETE;
2806 if (mode & RTLD_NOLOAD)
2807 lo_flags |= RTLD_LO_NOLOAD;
2808 if (ld_tracing != NULL)
2809 lo_flags |= RTLD_LO_TRACE;
2811 return (dlopen_object(name, fd, obj_main, lo_flags,
2812 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2816 dlopen_cleanup(Obj_Entry *obj)
2821 if (obj->refcount == 0)
2826 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2827 int mode, RtldLockState *lockstate)
2829 Obj_Entry **old_obj_tail;
2832 RtldLockState mlockstate;
2835 objlist_init(&initlist);
2837 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2838 wlock_acquire(rtld_bind_lock, &mlockstate);
2839 lockstate = &mlockstate;
2841 GDB_STATE(RT_ADD,NULL);
2843 old_obj_tail = obj_tail;
2845 if (name == NULL && fd == -1) {
2849 obj = load_object(name, fd, refobj, lo_flags);
2854 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2855 objlist_push_tail(&list_global, obj);
2856 if (*old_obj_tail != NULL) { /* We loaded something new. */
2857 assert(*old_obj_tail == obj);
2858 result = load_needed_objects(obj,
2859 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2863 result = rtld_verify_versions(&obj->dagmembers);
2864 if (result != -1 && ld_tracing)
2866 if (result == -1 || relocate_object_dag(obj,
2867 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2868 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2870 dlopen_cleanup(obj);
2872 } else if (lo_flags & RTLD_LO_EARLY) {
2874 * Do not call the init functions for early loaded
2875 * filtees. The image is still not initialized enough
2878 * Our object is found by the global object list and
2879 * will be ordered among all init calls done right
2880 * before transferring control to main.
2883 /* Make list of init functions to call. */
2884 initlist_add_objects(obj, &obj->next, &initlist);
2887 * Process all no_delete objects here, given them own
2888 * DAGs to prevent their dependencies from being unloaded.
2889 * This has to be done after we have loaded all of the
2890 * dependencies, so that we do not miss any.
2893 process_nodelete(obj);
2896 * Bump the reference counts for objects on this DAG. If
2897 * this is the first dlopen() call for the object that was
2898 * already loaded as a dependency, initialize the dag
2904 if ((lo_flags & RTLD_LO_TRACE) != 0)
2907 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2908 obj->z_nodelete) && !obj->ref_nodel) {
2909 dbg("obj %s nodelete", obj->path);
2911 obj->z_nodelete = obj->ref_nodel = true;
2915 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2917 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2919 if (!(lo_flags & RTLD_LO_EARLY)) {
2920 map_stacks_exec(lockstate);
2923 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2924 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2926 objlist_clear(&initlist);
2927 dlopen_cleanup(obj);
2928 if (lockstate == &mlockstate)
2929 lock_release(rtld_bind_lock, lockstate);
2933 if (!(lo_flags & RTLD_LO_EARLY)) {
2934 /* Call the init functions. */
2935 objlist_call_init(&initlist, lockstate);
2937 objlist_clear(&initlist);
2938 if (lockstate == &mlockstate)
2939 lock_release(rtld_bind_lock, lockstate);
2942 trace_loaded_objects(obj);
2943 if (lockstate == &mlockstate)
2944 lock_release(rtld_bind_lock, lockstate);
2949 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2953 const Obj_Entry *obj, *defobj;
2956 RtldLockState lockstate;
2964 symlook_init(&req, name);
2966 req.flags = flags | SYMLOOK_IN_PLT;
2967 req.lockstate = &lockstate;
2969 rlock_acquire(rtld_bind_lock, &lockstate);
2970 if (sigsetjmp(lockstate.env, 0) != 0)
2971 lock_upgrade(rtld_bind_lock, &lockstate);
2972 if (handle == NULL || handle == RTLD_NEXT ||
2973 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2975 if ((obj = obj_from_addr(retaddr)) == NULL) {
2976 _rtld_error("Cannot determine caller's shared object");
2977 lock_release(rtld_bind_lock, &lockstate);
2980 if (handle == NULL) { /* Just the caller's shared object. */
2981 res = symlook_obj(&req, obj);
2984 defobj = req.defobj_out;
2986 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2987 handle == RTLD_SELF) { /* ... caller included */
2988 if (handle == RTLD_NEXT)
2990 for (; obj != NULL; obj = obj->next) {
2991 res = symlook_obj(&req, obj);
2994 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2996 defobj = req.defobj_out;
2997 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3003 * Search the dynamic linker itself, and possibly resolve the
3004 * symbol from there. This is how the application links to
3005 * dynamic linker services such as dlopen.
3007 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3008 res = symlook_obj(&req, &obj_rtld);
3011 defobj = req.defobj_out;
3015 assert(handle == RTLD_DEFAULT);
3016 res = symlook_default(&req, obj);
3018 defobj = req.defobj_out;
3023 if ((obj = dlcheck(handle)) == NULL) {
3024 lock_release(rtld_bind_lock, &lockstate);
3028 donelist_init(&donelist);
3029 if (obj->mainprog) {
3030 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3031 res = symlook_global(&req, &donelist);
3034 defobj = req.defobj_out;
3037 * Search the dynamic linker itself, and possibly resolve the
3038 * symbol from there. This is how the application links to
3039 * dynamic linker services such as dlopen.
3041 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3042 res = symlook_obj(&req, &obj_rtld);
3045 defobj = req.defobj_out;
3050 /* Search the whole DAG rooted at the given object. */
3051 res = symlook_list(&req, &obj->dagmembers, &donelist);
3054 defobj = req.defobj_out;
3060 lock_release(rtld_bind_lock, &lockstate);
3063 * The value required by the caller is derived from the value
3064 * of the symbol. For the ia64 architecture, we need to
3065 * construct a function descriptor which the caller can use to
3066 * call the function with the right 'gp' value. For other
3067 * architectures and for non-functions, the value is simply
3068 * the relocated value of the symbol.
3070 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3071 return (make_function_pointer(def, defobj));
3072 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3073 return (rtld_resolve_ifunc(defobj, def));
3074 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3076 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3078 ti.ti_module = defobj->tlsindex;
3079 ti.ti_offset = def->st_value;
3080 return (__tls_get_addr(&ti));
3083 return (defobj->relocbase + def->st_value);
3086 _rtld_error("Undefined symbol \"%s\"", name);
3087 lock_release(rtld_bind_lock, &lockstate);
3092 dlsym(void *handle, const char *name)
3094 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3099 dlfunc(void *handle, const char *name)
3106 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3112 dlvsym(void *handle, const char *name, const char *version)
3116 ventry.name = version;
3118 ventry.hash = elf_hash(version);
3120 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3125 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3127 const Obj_Entry *obj;
3128 RtldLockState lockstate;
3130 rlock_acquire(rtld_bind_lock, &lockstate);
3131 obj = obj_from_addr(addr);
3133 _rtld_error("No shared object contains address");
3134 lock_release(rtld_bind_lock, &lockstate);
3137 rtld_fill_dl_phdr_info(obj, phdr_info);
3138 lock_release(rtld_bind_lock, &lockstate);
3143 dladdr(const void *addr, Dl_info *info)
3145 const Obj_Entry *obj;
3148 unsigned long symoffset;
3149 RtldLockState lockstate;
3151 rlock_acquire(rtld_bind_lock, &lockstate);
3152 obj = obj_from_addr(addr);
3154 _rtld_error("No shared object contains address");
3155 lock_release(rtld_bind_lock, &lockstate);
3158 info->dli_fname = obj->path;
3159 info->dli_fbase = obj->mapbase;
3160 info->dli_saddr = (void *)0;
3161 info->dli_sname = NULL;
3164 * Walk the symbol list looking for the symbol whose address is
3165 * closest to the address sent in.
3167 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3168 def = obj->symtab + symoffset;
3171 * For skip the symbol if st_shndx is either SHN_UNDEF or
3174 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3178 * If the symbol is greater than the specified address, or if it
3179 * is further away from addr than the current nearest symbol,
3182 symbol_addr = obj->relocbase + def->st_value;
3183 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3186 /* Update our idea of the nearest symbol. */
3187 info->dli_sname = obj->strtab + def->st_name;
3188 info->dli_saddr = symbol_addr;
3191 if (info->dli_saddr == addr)
3194 lock_release(rtld_bind_lock, &lockstate);
3199 dlinfo(void *handle, int request, void *p)
3201 const Obj_Entry *obj;
3202 RtldLockState lockstate;
3205 rlock_acquire(rtld_bind_lock, &lockstate);
3207 if (handle == NULL || handle == RTLD_SELF) {
3210 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3211 if ((obj = obj_from_addr(retaddr)) == NULL)
3212 _rtld_error("Cannot determine caller's shared object");
3214 obj = dlcheck(handle);
3217 lock_release(rtld_bind_lock, &lockstate);
3223 case RTLD_DI_LINKMAP:
3224 *((struct link_map const **)p) = &obj->linkmap;
3226 case RTLD_DI_ORIGIN:
3227 error = rtld_dirname(obj->path, p);
3230 case RTLD_DI_SERINFOSIZE:
3231 case RTLD_DI_SERINFO:
3232 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3236 _rtld_error("Invalid request %d passed to dlinfo()", request);
3240 lock_release(rtld_bind_lock, &lockstate);
3246 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3249 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3250 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
3251 STAILQ_FIRST(&obj->names)->name : obj->path;
3252 phdr_info->dlpi_phdr = obj->phdr;
3253 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3254 phdr_info->dlpi_tls_modid = obj->tlsindex;
3255 phdr_info->dlpi_tls_data = obj->tlsinit;
3256 phdr_info->dlpi_adds = obj_loads;
3257 phdr_info->dlpi_subs = obj_loads - obj_count;
3261 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3263 struct dl_phdr_info phdr_info;
3264 const Obj_Entry *obj;
3265 RtldLockState bind_lockstate, phdr_lockstate;
3268 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3269 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3273 for (obj = obj_list; obj != NULL; obj = obj->next) {
3274 rtld_fill_dl_phdr_info(obj, &phdr_info);
3275 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3279 lock_release(rtld_bind_lock, &bind_lockstate);
3280 lock_release(rtld_phdr_lock, &phdr_lockstate);
3286 fill_search_info(const char *dir, size_t dirlen, void *param)
3288 struct fill_search_info_args *arg;
3292 if (arg->request == RTLD_DI_SERINFOSIZE) {
3293 arg->serinfo->dls_cnt ++;
3294 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3296 struct dl_serpath *s_entry;
3298 s_entry = arg->serpath;
3299 s_entry->dls_name = arg->strspace;
3300 s_entry->dls_flags = arg->flags;
3302 strncpy(arg->strspace, dir, dirlen);
3303 arg->strspace[dirlen] = '\0';
3305 arg->strspace += dirlen + 1;
3313 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3315 struct dl_serinfo _info;
3316 struct fill_search_info_args args;
3318 args.request = RTLD_DI_SERINFOSIZE;
3319 args.serinfo = &_info;
3321 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3324 path_enumerate(obj->rpath, fill_search_info, &args);
3325 path_enumerate(ld_library_path, fill_search_info, &args);
3326 path_enumerate(obj->runpath, fill_search_info, &args);
3327 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3328 if (!obj->z_nodeflib)
3329 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3332 if (request == RTLD_DI_SERINFOSIZE) {
3333 info->dls_size = _info.dls_size;
3334 info->dls_cnt = _info.dls_cnt;
3338 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3339 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3343 args.request = RTLD_DI_SERINFO;
3344 args.serinfo = info;
3345 args.serpath = &info->dls_serpath[0];
3346 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3348 args.flags = LA_SER_RUNPATH;
3349 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3352 args.flags = LA_SER_LIBPATH;
3353 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3356 args.flags = LA_SER_RUNPATH;
3357 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3360 args.flags = LA_SER_CONFIG;
3361 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3365 args.flags = LA_SER_DEFAULT;
3366 if (!obj->z_nodeflib &&
3367 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3373 rtld_dirname(const char *path, char *bname)
3377 /* Empty or NULL string gets treated as "." */
3378 if (path == NULL || *path == '\0') {
3384 /* Strip trailing slashes */
3385 endp = path + strlen(path) - 1;
3386 while (endp > path && *endp == '/')
3389 /* Find the start of the dir */
3390 while (endp > path && *endp != '/')
3393 /* Either the dir is "/" or there are no slashes */
3395 bname[0] = *endp == '/' ? '/' : '.';
3401 } while (endp > path && *endp == '/');
3404 if (endp - path + 2 > PATH_MAX)
3406 _rtld_error("Filename is too long: %s", path);
3410 strncpy(bname, path, endp - path + 1);
3411 bname[endp - path + 1] = '\0';
3416 rtld_dirname_abs(const char *path, char *base)
3418 char base_rel[PATH_MAX];
3420 if (rtld_dirname(path, base) == -1)
3424 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3425 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3426 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3428 strcpy(base, base_rel);
3433 linkmap_add(Obj_Entry *obj)
3435 struct link_map *l = &obj->linkmap;
3436 struct link_map *prev;
3438 obj->linkmap.l_name = obj->path;
3439 obj->linkmap.l_addr = obj->mapbase;
3440 obj->linkmap.l_ld = obj->dynamic;
3442 /* GDB needs load offset on MIPS to use the symbols */
3443 obj->linkmap.l_offs = obj->relocbase;
3446 if (r_debug.r_map == NULL) {
3452 * Scan to the end of the list, but not past the entry for the
3453 * dynamic linker, which we want to keep at the very end.
3455 for (prev = r_debug.r_map;
3456 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3457 prev = prev->l_next)
3460 /* Link in the new entry. */
3462 l->l_next = prev->l_next;
3463 if (l->l_next != NULL)
3464 l->l_next->l_prev = l;
3469 linkmap_delete(Obj_Entry *obj)
3471 struct link_map *l = &obj->linkmap;
3473 if (l->l_prev == NULL) {
3474 if ((r_debug.r_map = l->l_next) != NULL)
3475 l->l_next->l_prev = NULL;
3479 if ((l->l_prev->l_next = l->l_next) != NULL)
3480 l->l_next->l_prev = l->l_prev;
3484 * Function for the debugger to set a breakpoint on to gain control.
3486 * The two parameters allow the debugger to easily find and determine
3487 * what the runtime loader is doing and to whom it is doing it.
3489 * When the loadhook trap is hit (r_debug_state, set at program
3490 * initialization), the arguments can be found on the stack:
3492 * +8 struct link_map *m
3493 * +4 struct r_debug *rd
3497 r_debug_state(struct r_debug* rd, struct link_map *m)
3500 * The following is a hack to force the compiler to emit calls to
3501 * this function, even when optimizing. If the function is empty,
3502 * the compiler is not obliged to emit any code for calls to it,
3503 * even when marked __noinline. However, gdb depends on those
3506 __compiler_membar();
3510 * A function called after init routines have completed. This can be used to
3511 * break before a program's entry routine is called, and can be used when
3512 * main is not available in the symbol table.
3515 _r_debug_postinit(struct link_map *m)
3518 /* See r_debug_state(). */
3519 __compiler_membar();
3523 * Get address of the pointer variable in the main program.
3524 * Prefer non-weak symbol over the weak one.
3526 static const void **
3527 get_program_var_addr(const char *name, RtldLockState *lockstate)
3532 symlook_init(&req, name);
3533 req.lockstate = lockstate;
3534 donelist_init(&donelist);
3535 if (symlook_global(&req, &donelist) != 0)
3537 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3538 return ((const void **)make_function_pointer(req.sym_out,
3540 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3541 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3543 return ((const void **)(req.defobj_out->relocbase +
3544 req.sym_out->st_value));
3548 * Set a pointer variable in the main program to the given value. This
3549 * is used to set key variables such as "environ" before any of the
3550 * init functions are called.
3553 set_program_var(const char *name, const void *value)
3557 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3558 dbg("\"%s\": *%p <-- %p", name, addr, value);
3564 * Search the global objects, including dependencies and main object,
3565 * for the given symbol.
3568 symlook_global(SymLook *req, DoneList *donelist)
3571 const Objlist_Entry *elm;
3574 symlook_init_from_req(&req1, req);
3576 /* Search all objects loaded at program start up. */
3577 if (req->defobj_out == NULL ||
3578 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3579 res = symlook_list(&req1, &list_main, donelist);
3580 if (res == 0 && (req->defobj_out == NULL ||
3581 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3582 req->sym_out = req1.sym_out;
3583 req->defobj_out = req1.defobj_out;
3584 assert(req->defobj_out != NULL);
3588 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3589 STAILQ_FOREACH(elm, &list_global, link) {
3590 if (req->defobj_out != NULL &&
3591 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3593 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3594 if (res == 0 && (req->defobj_out == NULL ||
3595 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3596 req->sym_out = req1.sym_out;
3597 req->defobj_out = req1.defobj_out;
3598 assert(req->defobj_out != NULL);
3602 return (req->sym_out != NULL ? 0 : ESRCH);
3606 * Given a symbol name in a referencing object, find the corresponding
3607 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3608 * no definition was found. Returns a pointer to the Obj_Entry of the
3609 * defining object via the reference parameter DEFOBJ_OUT.
3612 symlook_default(SymLook *req, const Obj_Entry *refobj)
3615 const Objlist_Entry *elm;
3619 donelist_init(&donelist);
3620 symlook_init_from_req(&req1, req);
3622 /* Look first in the referencing object if linked symbolically. */
3623 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3624 res = symlook_obj(&req1, refobj);
3626 req->sym_out = req1.sym_out;
3627 req->defobj_out = req1.defobj_out;
3628 assert(req->defobj_out != NULL);
3632 symlook_global(req, &donelist);
3634 /* Search all dlopened DAGs containing the referencing object. */
3635 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3636 if (req->sym_out != NULL &&
3637 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3639 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3640 if (res == 0 && (req->sym_out == NULL ||
3641 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3642 req->sym_out = req1.sym_out;
3643 req->defobj_out = req1.defobj_out;
3644 assert(req->defobj_out != NULL);
3649 * Search the dynamic linker itself, and possibly resolve the
3650 * symbol from there. This is how the application links to
3651 * dynamic linker services such as dlopen.
3653 if (req->sym_out == NULL ||
3654 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3655 res = symlook_obj(&req1, &obj_rtld);
3657 req->sym_out = req1.sym_out;
3658 req->defobj_out = req1.defobj_out;
3659 assert(req->defobj_out != NULL);
3663 return (req->sym_out != NULL ? 0 : ESRCH);
3667 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3670 const Obj_Entry *defobj;
3671 const Objlist_Entry *elm;
3677 STAILQ_FOREACH(elm, objlist, link) {
3678 if (donelist_check(dlp, elm->obj))
3680 symlook_init_from_req(&req1, req);
3681 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3682 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3684 defobj = req1.defobj_out;
3685 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3692 req->defobj_out = defobj;
3699 * Search the chain of DAGS cointed to by the given Needed_Entry
3700 * for a symbol of the given name. Each DAG is scanned completely
3701 * before advancing to the next one. Returns a pointer to the symbol,
3702 * or NULL if no definition was found.
3705 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3708 const Needed_Entry *n;
3709 const Obj_Entry *defobj;
3715 symlook_init_from_req(&req1, req);
3716 for (n = needed; n != NULL; n = n->next) {
3717 if (n->obj == NULL ||
3718 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3720 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3722 defobj = req1.defobj_out;
3723 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3729 req->defobj_out = defobj;
3736 * Search the symbol table of a single shared object for a symbol of
3737 * the given name and version, if requested. Returns a pointer to the
3738 * symbol, or NULL if no definition was found. If the object is
3739 * filter, return filtered symbol from filtee.
3741 * The symbol's hash value is passed in for efficiency reasons; that
3742 * eliminates many recomputations of the hash value.
3745 symlook_obj(SymLook *req, const Obj_Entry *obj)
3749 int flags, res, mres;
3752 * If there is at least one valid hash at this point, we prefer to
3753 * use the faster GNU version if available.
3755 if (obj->valid_hash_gnu)
3756 mres = symlook_obj1_gnu(req, obj);
3757 else if (obj->valid_hash_sysv)
3758 mres = symlook_obj1_sysv(req, obj);
3763 if (obj->needed_filtees != NULL) {
3764 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3765 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3766 donelist_init(&donelist);
3767 symlook_init_from_req(&req1, req);
3768 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3770 req->sym_out = req1.sym_out;
3771 req->defobj_out = req1.defobj_out;
3775 if (obj->needed_aux_filtees != NULL) {
3776 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3777 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3778 donelist_init(&donelist);
3779 symlook_init_from_req(&req1, req);
3780 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3782 req->sym_out = req1.sym_out;
3783 req->defobj_out = req1.defobj_out;
3791 /* Symbol match routine common to both hash functions */
3793 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3794 const unsigned long symnum)
3797 const Elf_Sym *symp;
3800 symp = obj->symtab + symnum;
3801 strp = obj->strtab + symp->st_name;
3803 switch (ELF_ST_TYPE(symp->st_info)) {
3809 if (symp->st_value == 0)
3813 if (symp->st_shndx != SHN_UNDEF)
3816 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3817 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3824 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3827 if (req->ventry == NULL) {
3828 if (obj->versyms != NULL) {
3829 verndx = VER_NDX(obj->versyms[symnum]);
3830 if (verndx > obj->vernum) {
3832 "%s: symbol %s references wrong version %d",
3833 obj->path, obj->strtab + symnum, verndx);
3837 * If we are not called from dlsym (i.e. this
3838 * is a normal relocation from unversioned
3839 * binary), accept the symbol immediately if
3840 * it happens to have first version after this
3841 * shared object became versioned. Otherwise,
3842 * if symbol is versioned and not hidden,
3843 * remember it. If it is the only symbol with
3844 * this name exported by the shared object, it
3845 * will be returned as a match by the calling
3846 * function. If symbol is global (verndx < 2)
3847 * accept it unconditionally.
3849 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3850 verndx == VER_NDX_GIVEN) {
3851 result->sym_out = symp;
3854 else if (verndx >= VER_NDX_GIVEN) {
3855 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3857 if (result->vsymp == NULL)
3858 result->vsymp = symp;
3864 result->sym_out = symp;
3867 if (obj->versyms == NULL) {
3868 if (object_match_name(obj, req->ventry->name)) {
3869 _rtld_error("%s: object %s should provide version %s "
3870 "for symbol %s", obj_rtld.path, obj->path,
3871 req->ventry->name, obj->strtab + symnum);
3875 verndx = VER_NDX(obj->versyms[symnum]);
3876 if (verndx > obj->vernum) {
3877 _rtld_error("%s: symbol %s references wrong version %d",
3878 obj->path, obj->strtab + symnum, verndx);
3881 if (obj->vertab[verndx].hash != req->ventry->hash ||
3882 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3884 * Version does not match. Look if this is a
3885 * global symbol and if it is not hidden. If
3886 * global symbol (verndx < 2) is available,
3887 * use it. Do not return symbol if we are
3888 * called by dlvsym, because dlvsym looks for
3889 * a specific version and default one is not
3890 * what dlvsym wants.
3892 if ((req->flags & SYMLOOK_DLSYM) ||
3893 (verndx >= VER_NDX_GIVEN) ||
3894 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3898 result->sym_out = symp;
3903 * Search for symbol using SysV hash function.
3904 * obj->buckets is known not to be NULL at this point; the test for this was
3905 * performed with the obj->valid_hash_sysv assignment.
3908 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
3910 unsigned long symnum;
3911 Sym_Match_Result matchres;
3913 matchres.sym_out = NULL;
3914 matchres.vsymp = NULL;
3915 matchres.vcount = 0;
3917 for (symnum = obj->buckets[req->hash % obj->nbuckets];
3918 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3919 if (symnum >= obj->nchains)
3920 return (ESRCH); /* Bad object */
3922 if (matched_symbol(req, obj, &matchres, symnum)) {
3923 req->sym_out = matchres.sym_out;
3924 req->defobj_out = obj;
3928 if (matchres.vcount == 1) {
3929 req->sym_out = matchres.vsymp;
3930 req->defobj_out = obj;
3936 /* Search for symbol using GNU hash function */
3938 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
3940 Elf_Addr bloom_word;
3941 const Elf32_Word *hashval;
3943 Sym_Match_Result matchres;
3944 unsigned int h1, h2;
3945 unsigned long symnum;
3947 matchres.sym_out = NULL;
3948 matchres.vsymp = NULL;
3949 matchres.vcount = 0;
3951 /* Pick right bitmask word from Bloom filter array */
3952 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
3953 obj->maskwords_bm_gnu];
3955 /* Calculate modulus word size of gnu hash and its derivative */
3956 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
3957 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
3959 /* Filter out the "definitely not in set" queries */
3960 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
3963 /* Locate hash chain and corresponding value element*/
3964 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
3967 hashval = &obj->chain_zero_gnu[bucket];
3969 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
3970 symnum = hashval - obj->chain_zero_gnu;
3971 if (matched_symbol(req, obj, &matchres, symnum)) {
3972 req->sym_out = matchres.sym_out;
3973 req->defobj_out = obj;
3977 } while ((*hashval++ & 1) == 0);
3978 if (matchres.vcount == 1) {
3979 req->sym_out = matchres.vsymp;
3980 req->defobj_out = obj;
3987 trace_loaded_objects(Obj_Entry *obj)
3989 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3992 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3995 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3996 fmt1 = "\t%o => %p (%x)\n";
3998 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3999 fmt2 = "\t%o (%x)\n";
4001 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4003 for (; obj; obj = obj->next) {
4004 Needed_Entry *needed;
4008 if (list_containers && obj->needed != NULL)
4009 rtld_printf("%s:\n", obj->path);
4010 for (needed = obj->needed; needed; needed = needed->next) {
4011 if (needed->obj != NULL) {
4012 if (needed->obj->traced && !list_containers)
4014 needed->obj->traced = true;
4015 path = needed->obj->path;
4019 name = (char *)obj->strtab + needed->name;
4020 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4022 fmt = is_lib ? fmt1 : fmt2;
4023 while ((c = *fmt++) != '\0') {
4049 rtld_putstr(main_local);
4052 rtld_putstr(obj_main->path);
4059 rtld_printf("%d", sodp->sod_major);
4062 rtld_printf("%d", sodp->sod_minor);
4069 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4082 * Unload a dlopened object and its dependencies from memory and from
4083 * our data structures. It is assumed that the DAG rooted in the
4084 * object has already been unreferenced, and that the object has a
4085 * reference count of 0.
4088 unload_object(Obj_Entry *root)
4093 assert(root->refcount == 0);
4096 * Pass over the DAG removing unreferenced objects from
4097 * appropriate lists.
4099 unlink_object(root);
4101 /* Unmap all objects that are no longer referenced. */
4102 linkp = &obj_list->next;
4103 while ((obj = *linkp) != NULL) {
4104 if (obj->refcount == 0) {
4105 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4107 dbg("unloading \"%s\"", obj->path);
4108 unload_filtees(root);
4109 munmap(obj->mapbase, obj->mapsize);
4110 linkmap_delete(obj);
4121 unlink_object(Obj_Entry *root)
4125 if (root->refcount == 0) {
4126 /* Remove the object from the RTLD_GLOBAL list. */
4127 objlist_remove(&list_global, root);
4129 /* Remove the object from all objects' DAG lists. */
4130 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4131 objlist_remove(&elm->obj->dldags, root);
4132 if (elm->obj != root)
4133 unlink_object(elm->obj);
4139 ref_dag(Obj_Entry *root)
4143 assert(root->dag_inited);
4144 STAILQ_FOREACH(elm, &root->dagmembers, link)
4145 elm->obj->refcount++;
4149 unref_dag(Obj_Entry *root)
4153 assert(root->dag_inited);
4154 STAILQ_FOREACH(elm, &root->dagmembers, link)
4155 elm->obj->refcount--;
4159 * Common code for MD __tls_get_addr().
4161 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4163 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4165 Elf_Addr *newdtv, *dtv;
4166 RtldLockState lockstate;
4170 /* Check dtv generation in case new modules have arrived */
4171 if (dtv[0] != tls_dtv_generation) {
4172 wlock_acquire(rtld_bind_lock, &lockstate);
4173 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4175 if (to_copy > tls_max_index)
4176 to_copy = tls_max_index;
4177 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4178 newdtv[0] = tls_dtv_generation;
4179 newdtv[1] = tls_max_index;
4181 lock_release(rtld_bind_lock, &lockstate);
4182 dtv = *dtvp = newdtv;
4185 /* Dynamically allocate module TLS if necessary */
4186 if (dtv[index + 1] == 0) {
4187 /* Signal safe, wlock will block out signals. */
4188 wlock_acquire(rtld_bind_lock, &lockstate);
4189 if (!dtv[index + 1])
4190 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4191 lock_release(rtld_bind_lock, &lockstate);
4193 return ((void *)(dtv[index + 1] + offset));
4197 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4202 /* Check dtv generation in case new modules have arrived */
4203 if (__predict_true(dtv[0] == tls_dtv_generation &&
4204 dtv[index + 1] != 0))
4205 return ((void *)(dtv[index + 1] + offset));
4206 return (tls_get_addr_slow(dtvp, index, offset));
4209 #if defined(__arm__) || defined(__ia64__) || defined(__powerpc__)
4212 * Allocate Static TLS using the Variant I method.
4215 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4224 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4227 assert(tcbsize >= TLS_TCB_SIZE);
4228 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4229 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4231 if (oldtcb != NULL) {
4232 memcpy(tls, oldtcb, tls_static_space);
4235 /* Adjust the DTV. */
4237 for (i = 0; i < dtv[1]; i++) {
4238 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4239 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4240 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4244 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4246 dtv[0] = tls_dtv_generation;
4247 dtv[1] = tls_max_index;
4249 for (obj = objs; obj; obj = obj->next) {
4250 if (obj->tlsoffset > 0) {
4251 addr = (Elf_Addr)tls + obj->tlsoffset;
4252 if (obj->tlsinitsize > 0)
4253 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4254 if (obj->tlssize > obj->tlsinitsize)
4255 memset((void*) (addr + obj->tlsinitsize), 0,
4256 obj->tlssize - obj->tlsinitsize);
4257 dtv[obj->tlsindex + 1] = addr;
4266 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4269 Elf_Addr tlsstart, tlsend;
4272 assert(tcbsize >= TLS_TCB_SIZE);
4274 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4275 tlsend = tlsstart + tls_static_space;
4277 dtv = *(Elf_Addr **)tlsstart;
4279 for (i = 0; i < dtvsize; i++) {
4280 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4281 free((void*)dtv[i+2]);
4290 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
4294 * Allocate Static TLS using the Variant II method.
4297 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4300 size_t size, ralign;
4302 Elf_Addr *dtv, *olddtv;
4303 Elf_Addr segbase, oldsegbase, addr;
4307 if (tls_static_max_align > ralign)
4308 ralign = tls_static_max_align;
4309 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4311 assert(tcbsize >= 2*sizeof(Elf_Addr));
4312 tls = malloc_aligned(size, ralign);
4313 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4315 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4316 ((Elf_Addr*)segbase)[0] = segbase;
4317 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4319 dtv[0] = tls_dtv_generation;
4320 dtv[1] = tls_max_index;
4324 * Copy the static TLS block over whole.
4326 oldsegbase = (Elf_Addr) oldtls;
4327 memcpy((void *)(segbase - tls_static_space),
4328 (const void *)(oldsegbase - tls_static_space),
4332 * If any dynamic TLS blocks have been created tls_get_addr(),
4335 olddtv = ((Elf_Addr**)oldsegbase)[1];
4336 for (i = 0; i < olddtv[1]; i++) {
4337 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4338 dtv[i+2] = olddtv[i+2];
4344 * We assume that this block was the one we created with
4345 * allocate_initial_tls().
4347 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4349 for (obj = objs; obj; obj = obj->next) {
4350 if (obj->tlsoffset) {
4351 addr = segbase - obj->tlsoffset;
4352 memset((void*) (addr + obj->tlsinitsize),
4353 0, obj->tlssize - obj->tlsinitsize);
4355 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4356 dtv[obj->tlsindex + 1] = addr;
4361 return (void*) segbase;
4365 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4368 size_t size, ralign;
4370 Elf_Addr tlsstart, tlsend;
4373 * Figure out the size of the initial TLS block so that we can
4374 * find stuff which ___tls_get_addr() allocated dynamically.
4377 if (tls_static_max_align > ralign)
4378 ralign = tls_static_max_align;
4379 size = round(tls_static_space, ralign);
4381 dtv = ((Elf_Addr**)tls)[1];
4383 tlsend = (Elf_Addr) tls;
4384 tlsstart = tlsend - size;
4385 for (i = 0; i < dtvsize; i++) {
4386 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4387 free_aligned((void *)dtv[i + 2]);
4391 free_aligned((void *)tlsstart);
4398 * Allocate TLS block for module with given index.
4401 allocate_module_tls(int index)
4406 for (obj = obj_list; obj; obj = obj->next) {
4407 if (obj->tlsindex == index)
4411 _rtld_error("Can't find module with TLS index %d", index);
4415 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4416 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4417 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4423 allocate_tls_offset(Obj_Entry *obj)
4430 if (obj->tlssize == 0) {
4431 obj->tls_done = true;
4435 if (obj->tlsindex == 1)
4436 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4438 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4439 obj->tlssize, obj->tlsalign);
4442 * If we have already fixed the size of the static TLS block, we
4443 * must stay within that size. When allocating the static TLS, we
4444 * leave a small amount of space spare to be used for dynamically
4445 * loading modules which use static TLS.
4447 if (tls_static_space != 0) {
4448 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4450 } else if (obj->tlsalign > tls_static_max_align) {
4451 tls_static_max_align = obj->tlsalign;
4454 tls_last_offset = obj->tlsoffset = off;
4455 tls_last_size = obj->tlssize;
4456 obj->tls_done = true;
4462 free_tls_offset(Obj_Entry *obj)
4466 * If we were the last thing to allocate out of the static TLS
4467 * block, we give our space back to the 'allocator'. This is a
4468 * simplistic workaround to allow libGL.so.1 to be loaded and
4469 * unloaded multiple times.
4471 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4472 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4473 tls_last_offset -= obj->tlssize;
4479 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4482 RtldLockState lockstate;
4484 wlock_acquire(rtld_bind_lock, &lockstate);
4485 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4486 lock_release(rtld_bind_lock, &lockstate);
4491 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4493 RtldLockState lockstate;
4495 wlock_acquire(rtld_bind_lock, &lockstate);
4496 free_tls(tcb, tcbsize, tcbalign);
4497 lock_release(rtld_bind_lock, &lockstate);
4501 object_add_name(Obj_Entry *obj, const char *name)
4507 entry = malloc(sizeof(Name_Entry) + len);
4509 if (entry != NULL) {
4510 strcpy(entry->name, name);
4511 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4516 object_match_name(const Obj_Entry *obj, const char *name)
4520 STAILQ_FOREACH(entry, &obj->names, link) {
4521 if (strcmp(name, entry->name) == 0)
4528 locate_dependency(const Obj_Entry *obj, const char *name)
4530 const Objlist_Entry *entry;
4531 const Needed_Entry *needed;
4533 STAILQ_FOREACH(entry, &list_main, link) {
4534 if (object_match_name(entry->obj, name))
4538 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4539 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4540 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4542 * If there is DT_NEEDED for the name we are looking for,
4543 * we are all set. Note that object might not be found if
4544 * dependency was not loaded yet, so the function can
4545 * return NULL here. This is expected and handled
4546 * properly by the caller.
4548 return (needed->obj);
4551 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4557 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4558 const Elf_Vernaux *vna)
4560 const Elf_Verdef *vd;
4561 const char *vername;
4563 vername = refobj->strtab + vna->vna_name;
4564 vd = depobj->verdef;
4566 _rtld_error("%s: version %s required by %s not defined",
4567 depobj->path, vername, refobj->path);
4571 if (vd->vd_version != VER_DEF_CURRENT) {
4572 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4573 depobj->path, vd->vd_version);
4576 if (vna->vna_hash == vd->vd_hash) {
4577 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4578 ((char *)vd + vd->vd_aux);
4579 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4582 if (vd->vd_next == 0)
4584 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4586 if (vna->vna_flags & VER_FLG_WEAK)
4588 _rtld_error("%s: version %s required by %s not found",
4589 depobj->path, vername, refobj->path);
4594 rtld_verify_object_versions(Obj_Entry *obj)
4596 const Elf_Verneed *vn;
4597 const Elf_Verdef *vd;
4598 const Elf_Verdaux *vda;
4599 const Elf_Vernaux *vna;
4600 const Obj_Entry *depobj;
4601 int maxvernum, vernum;
4603 if (obj->ver_checked)
4605 obj->ver_checked = true;
4609 * Walk over defined and required version records and figure out
4610 * max index used by any of them. Do very basic sanity checking
4614 while (vn != NULL) {
4615 if (vn->vn_version != VER_NEED_CURRENT) {
4616 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4617 obj->path, vn->vn_version);
4620 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4622 vernum = VER_NEED_IDX(vna->vna_other);
4623 if (vernum > maxvernum)
4625 if (vna->vna_next == 0)
4627 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4629 if (vn->vn_next == 0)
4631 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4635 while (vd != NULL) {
4636 if (vd->vd_version != VER_DEF_CURRENT) {
4637 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4638 obj->path, vd->vd_version);
4641 vernum = VER_DEF_IDX(vd->vd_ndx);
4642 if (vernum > maxvernum)
4644 if (vd->vd_next == 0)
4646 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4653 * Store version information in array indexable by version index.
4654 * Verify that object version requirements are satisfied along the
4657 obj->vernum = maxvernum + 1;
4658 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4661 while (vd != NULL) {
4662 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4663 vernum = VER_DEF_IDX(vd->vd_ndx);
4664 assert(vernum <= maxvernum);
4665 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4666 obj->vertab[vernum].hash = vd->vd_hash;
4667 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4668 obj->vertab[vernum].file = NULL;
4669 obj->vertab[vernum].flags = 0;
4671 if (vd->vd_next == 0)
4673 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4677 while (vn != NULL) {
4678 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4681 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4683 if (check_object_provided_version(obj, depobj, vna))
4685 vernum = VER_NEED_IDX(vna->vna_other);
4686 assert(vernum <= maxvernum);
4687 obj->vertab[vernum].hash = vna->vna_hash;
4688 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4689 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4690 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4691 VER_INFO_HIDDEN : 0;
4692 if (vna->vna_next == 0)
4694 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4696 if (vn->vn_next == 0)
4698 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4704 rtld_verify_versions(const Objlist *objlist)
4706 Objlist_Entry *entry;
4710 STAILQ_FOREACH(entry, objlist, link) {
4712 * Skip dummy objects or objects that have their version requirements
4715 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4717 if (rtld_verify_object_versions(entry->obj) == -1) {
4719 if (ld_tracing == NULL)
4723 if (rc == 0 || ld_tracing != NULL)
4724 rc = rtld_verify_object_versions(&obj_rtld);
4729 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4734 vernum = VER_NDX(obj->versyms[symnum]);
4735 if (vernum >= obj->vernum) {
4736 _rtld_error("%s: symbol %s has wrong verneed value %d",
4737 obj->path, obj->strtab + symnum, vernum);
4738 } else if (obj->vertab[vernum].hash != 0) {
4739 return &obj->vertab[vernum];
4746 _rtld_get_stack_prot(void)
4749 return (stack_prot);
4753 map_stacks_exec(RtldLockState *lockstate)
4755 void (*thr_map_stacks_exec)(void);
4757 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4759 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4760 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4761 if (thr_map_stacks_exec != NULL) {
4762 stack_prot |= PROT_EXEC;
4763 thr_map_stacks_exec();
4768 symlook_init(SymLook *dst, const char *name)
4771 bzero(dst, sizeof(*dst));
4773 dst->hash = elf_hash(name);
4774 dst->hash_gnu = gnu_hash(name);
4778 symlook_init_from_req(SymLook *dst, const SymLook *src)
4781 dst->name = src->name;
4782 dst->hash = src->hash;
4783 dst->hash_gnu = src->hash_gnu;
4784 dst->ventry = src->ventry;
4785 dst->flags = src->flags;
4786 dst->defobj_out = NULL;
4787 dst->sym_out = NULL;
4788 dst->lockstate = src->lockstate;
4792 * Overrides for libc_pic-provided functions.
4796 __getosreldate(void)
4806 oid[1] = KERN_OSRELDATE;
4808 len = sizeof(osrel);
4809 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4810 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4822 void (*__cleanup)(void);
4823 int __isthreaded = 0;
4824 int _thread_autoinit_dummy_decl = 1;
4827 * No unresolved symbols for rtld.
4830 __pthread_cxa_finalize(struct dl_phdr_info *a)
4835 __stack_chk_fail(void)
4838 _rtld_error("stack overflow detected; terminated");
4841 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
4847 _rtld_error("buffer overflow detected; terminated");
4852 rtld_strerror(int errnum)
4855 if (errnum < 0 || errnum >= sys_nerr)
4856 return ("Unknown error");
4857 return (sys_errlist[errnum]);