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;
168 static char *error_message; /* Message for dlerror(), or NULL */
169 struct r_debug r_debug; /* for GDB; */
170 static bool libmap_disable; /* Disable libmap */
171 static bool ld_loadfltr; /* Immediate filters processing */
172 static char *libmap_override; /* Maps to use in addition to libmap.conf */
173 static bool trust; /* False for setuid and setgid programs */
174 static bool dangerous_ld_env; /* True if environment variables have been
175 used to affect the libraries loaded */
176 static char *ld_bind_now; /* Environment variable for immediate binding */
177 static char *ld_debug; /* Environment variable for debugging */
178 static char *ld_library_path; /* Environment variable for search path */
179 static char *ld_preload; /* Environment variable for libraries to
181 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
182 static char *ld_tracing; /* Called from ldd to print libs */
183 static char *ld_utrace; /* Use utrace() to log events. */
184 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
185 static Obj_Entry **obj_tail; /* Link field of last object in list */
186 static Obj_Entry *obj_main; /* The main program shared object */
187 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
188 static unsigned int obj_count; /* Number of objects in obj_list */
189 static unsigned int obj_loads; /* Number of objects in obj_list */
191 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
192 STAILQ_HEAD_INITIALIZER(list_global);
193 static Objlist list_main = /* Objects loaded at program startup */
194 STAILQ_HEAD_INITIALIZER(list_main);
195 static Objlist list_fini = /* Objects needing fini() calls */
196 STAILQ_HEAD_INITIALIZER(list_fini);
198 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
200 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
202 extern Elf_Dyn _DYNAMIC;
203 #pragma weak _DYNAMIC
204 #ifndef RTLD_IS_DYNAMIC
205 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
208 int osreldate, pagesize;
210 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
212 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
213 static int max_stack_flags;
216 * Global declarations normally provided by crt1. The dynamic linker is
217 * not built with crt1, so we have to provide them ourselves.
223 * Used to pass argc, argv to init functions.
229 * Globals to control TLS allocation.
231 size_t tls_last_offset; /* Static TLS offset of last module */
232 size_t tls_last_size; /* Static TLS size of last module */
233 size_t tls_static_space; /* Static TLS space allocated */
234 size_t tls_static_max_align;
235 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
236 int tls_max_index = 1; /* Largest module index allocated */
238 bool ld_library_path_rpath = true;
241 * Fill in a DoneList with an allocation large enough to hold all of
242 * the currently-loaded objects. Keep this as a macro since it calls
243 * alloca and we want that to occur within the scope of the caller.
245 #define donelist_init(dlp) \
246 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
247 assert((dlp)->objs != NULL), \
248 (dlp)->num_alloc = obj_count, \
251 #define UTRACE_DLOPEN_START 1
252 #define UTRACE_DLOPEN_STOP 2
253 #define UTRACE_DLCLOSE_START 3
254 #define UTRACE_DLCLOSE_STOP 4
255 #define UTRACE_LOAD_OBJECT 5
256 #define UTRACE_UNLOAD_OBJECT 6
257 #define UTRACE_ADD_RUNDEP 7
258 #define UTRACE_PRELOAD_FINISHED 8
259 #define UTRACE_INIT_CALL 9
260 #define UTRACE_FINI_CALL 10
263 char sig[4]; /* 'RTLD' */
266 void *mapbase; /* Used for 'parent' and 'init/fini' */
268 int refcnt; /* Used for 'mode' */
269 char name[MAXPATHLEN];
272 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
273 if (ld_utrace != NULL) \
274 ld_utrace_log(e, h, mb, ms, r, n); \
278 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
279 int refcnt, const char *name)
281 struct utrace_rtld ut;
289 ut.mapbase = mapbase;
290 ut.mapsize = mapsize;
292 bzero(ut.name, sizeof(ut.name));
294 strlcpy(ut.name, name, sizeof(ut.name));
295 utrace(&ut, sizeof(ut));
299 * Main entry point for dynamic linking. The first argument is the
300 * stack pointer. The stack is expected to be laid out as described
301 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
302 * Specifically, the stack pointer points to a word containing
303 * ARGC. Following that in the stack is a null-terminated sequence
304 * of pointers to argument strings. Then comes a null-terminated
305 * sequence of pointers to environment strings. Finally, there is a
306 * sequence of "auxiliary vector" entries.
308 * The second argument points to a place to store the dynamic linker's
309 * exit procedure pointer and the third to a place to store the main
312 * The return value is the main program's entry point.
315 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
317 Elf_Auxinfo *aux_info[AT_COUNT];
325 Objlist_Entry *entry;
327 Obj_Entry **preload_tail;
328 Obj_Entry *last_interposer;
330 RtldLockState lockstate;
331 char *library_path_rpath;
336 * On entry, the dynamic linker itself has not been relocated yet.
337 * Be very careful not to reference any global data until after
338 * init_rtld has returned. It is OK to reference file-scope statics
339 * and string constants, and to call static and global functions.
342 /* Find the auxiliary vector on the stack. */
345 sp += argc + 1; /* Skip over arguments and NULL terminator */
347 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
349 aux = (Elf_Auxinfo *) sp;
351 /* Digest the auxiliary vector. */
352 for (i = 0; i < AT_COUNT; i++)
354 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
355 if (auxp->a_type < AT_COUNT)
356 aux_info[auxp->a_type] = auxp;
359 /* Initialize and relocate ourselves. */
360 assert(aux_info[AT_BASE] != NULL);
361 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
363 __progname = obj_rtld.path;
364 argv0 = argv[0] != NULL ? argv[0] : "(null)";
369 if (aux_info[AT_CANARY] != NULL &&
370 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
371 i = aux_info[AT_CANARYLEN]->a_un.a_val;
372 if (i > sizeof(__stack_chk_guard))
373 i = sizeof(__stack_chk_guard);
374 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
379 len = sizeof(__stack_chk_guard);
380 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
381 len != sizeof(__stack_chk_guard)) {
382 /* If sysctl was unsuccessful, use the "terminator canary". */
383 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
384 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
385 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
386 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
390 trust = !issetugid();
392 ld_bind_now = getenv(LD_ "BIND_NOW");
394 * If the process is tainted, then we un-set the dangerous environment
395 * variables. The process will be marked as tainted until setuid(2)
396 * is called. If any child process calls setuid(2) we do not want any
397 * future processes to honor the potentially un-safe variables.
400 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
401 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
402 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
403 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
404 _rtld_error("environment corrupt; aborting");
408 ld_debug = getenv(LD_ "DEBUG");
409 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
410 libmap_override = getenv(LD_ "LIBMAP");
411 ld_library_path = getenv(LD_ "LIBRARY_PATH");
412 ld_preload = getenv(LD_ "PRELOAD");
413 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
414 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
415 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
416 if (library_path_rpath != NULL) {
417 if (library_path_rpath[0] == 'y' ||
418 library_path_rpath[0] == 'Y' ||
419 library_path_rpath[0] == '1')
420 ld_library_path_rpath = true;
422 ld_library_path_rpath = false;
424 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
425 (ld_library_path != NULL) || (ld_preload != NULL) ||
426 (ld_elf_hints_path != NULL) || ld_loadfltr;
427 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
428 ld_utrace = getenv(LD_ "UTRACE");
430 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
431 ld_elf_hints_path = _PATH_ELF_HINTS;
433 if (ld_debug != NULL && *ld_debug != '\0')
435 dbg("%s is initialized, base address = %p", __progname,
436 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
437 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
438 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
440 dbg("initializing thread locks");
444 * Load the main program, or process its program header if it is
447 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
448 int fd = aux_info[AT_EXECFD]->a_un.a_val;
449 dbg("loading main program");
450 obj_main = map_object(fd, argv0, NULL);
452 if (obj_main == NULL)
454 max_stack_flags = obj->stack_flags;
455 } else { /* Main program already loaded. */
456 const Elf_Phdr *phdr;
460 dbg("processing main program's program header");
461 assert(aux_info[AT_PHDR] != NULL);
462 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
463 assert(aux_info[AT_PHNUM] != NULL);
464 phnum = aux_info[AT_PHNUM]->a_un.a_val;
465 assert(aux_info[AT_PHENT] != NULL);
466 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
467 assert(aux_info[AT_ENTRY] != NULL);
468 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
469 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
473 if (aux_info[AT_EXECPATH] != 0) {
475 char buf[MAXPATHLEN];
477 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
478 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
479 if (kexecpath[0] == '/')
480 obj_main->path = kexecpath;
481 else if (getcwd(buf, sizeof(buf)) == NULL ||
482 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
483 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
484 obj_main->path = xstrdup(argv0);
486 obj_main->path = xstrdup(buf);
488 dbg("No AT_EXECPATH");
489 obj_main->path = xstrdup(argv0);
491 dbg("obj_main path %s", obj_main->path);
492 obj_main->mainprog = true;
494 if (aux_info[AT_STACKPROT] != NULL &&
495 aux_info[AT_STACKPROT]->a_un.a_val != 0)
496 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
499 * Get the actual dynamic linker pathname from the executable if
500 * possible. (It should always be possible.) That ensures that
501 * gdb will find the right dynamic linker even if a non-standard
504 if (obj_main->interp != NULL &&
505 strcmp(obj_main->interp, obj_rtld.path) != 0) {
507 obj_rtld.path = xstrdup(obj_main->interp);
508 __progname = obj_rtld.path;
511 digest_dynamic(obj_main, 0);
512 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
513 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
514 obj_main->dynsymcount);
516 linkmap_add(obj_main);
517 linkmap_add(&obj_rtld);
519 /* Link the main program into the list of objects. */
520 *obj_tail = obj_main;
521 obj_tail = &obj_main->next;
525 /* Initialize a fake symbol for resolving undefined weak references. */
526 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
527 sym_zero.st_shndx = SHN_UNDEF;
528 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
531 libmap_disable = (bool)lm_init(libmap_override);
533 dbg("loading LD_PRELOAD libraries");
534 if (load_preload_objects() == -1)
536 preload_tail = obj_tail;
538 dbg("loading needed objects");
539 if (load_needed_objects(obj_main, 0) == -1)
542 /* Make a list of all objects loaded at startup. */
543 last_interposer = obj_main;
544 for (obj = obj_list; obj != NULL; obj = obj->next) {
545 if (obj->z_interpose && obj != obj_main) {
546 objlist_put_after(&list_main, last_interposer, obj);
547 last_interposer = obj;
549 objlist_push_tail(&list_main, obj);
554 dbg("checking for required versions");
555 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
558 if (ld_tracing) { /* We're done */
559 trace_loaded_objects(obj_main);
563 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
564 dump_relocations(obj_main);
569 * Processing tls relocations requires having the tls offsets
570 * initialized. Prepare offsets before starting initial
571 * relocation processing.
573 dbg("initializing initial thread local storage offsets");
574 STAILQ_FOREACH(entry, &list_main, link) {
576 * Allocate all the initial objects out of the static TLS
577 * block even if they didn't ask for it.
579 allocate_tls_offset(entry->obj);
582 if (relocate_objects(obj_main,
583 ld_bind_now != NULL && *ld_bind_now != '\0',
584 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
587 dbg("doing copy relocations");
588 if (do_copy_relocations(obj_main) == -1)
591 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
592 dump_relocations(obj_main);
597 * Setup TLS for main thread. This must be done after the
598 * relocations are processed, since tls initialization section
599 * might be the subject for relocations.
601 dbg("initializing initial thread local storage");
602 allocate_initial_tls(obj_list);
604 dbg("initializing key program variables");
605 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
606 set_program_var("environ", env);
607 set_program_var("__elf_aux_vector", aux);
609 /* Make a list of init functions to call. */
610 objlist_init(&initlist);
611 initlist_add_objects(obj_list, preload_tail, &initlist);
613 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
615 map_stacks_exec(NULL);
617 dbg("resolving ifuncs");
618 if (resolve_objects_ifunc(obj_main,
619 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
623 if (!obj_main->crt_no_init) {
625 * Make sure we don't call the main program's init and fini
626 * functions for binaries linked with old crt1 which calls
629 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
630 obj_main->preinit_array = obj_main->init_array =
631 obj_main->fini_array = (Elf_Addr)NULL;
634 wlock_acquire(rtld_bind_lock, &lockstate);
635 if (obj_main->crt_no_init)
637 objlist_call_init(&initlist, &lockstate);
638 objlist_clear(&initlist);
639 dbg("loading filtees");
640 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
641 if (ld_loadfltr || obj->z_loadfltr)
642 load_filtees(obj, 0, &lockstate);
644 lock_release(rtld_bind_lock, &lockstate);
646 dbg("transferring control to program entry point = %p", obj_main->entry);
648 /* Return the exit procedure and the program entry point. */
649 *exit_proc = rtld_exit;
651 return (func_ptr_type) obj_main->entry;
655 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
660 ptr = (void *)make_function_pointer(def, obj);
661 target = ((Elf_Addr (*)(void))ptr)();
662 return ((void *)target);
666 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
670 const Obj_Entry *defobj;
673 RtldLockState lockstate;
675 rlock_acquire(rtld_bind_lock, &lockstate);
676 if (sigsetjmp(lockstate.env, 0) != 0)
677 lock_upgrade(rtld_bind_lock, &lockstate);
679 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
681 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
683 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
684 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
688 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
689 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
691 target = (Elf_Addr)(defobj->relocbase + def->st_value);
693 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
694 defobj->strtab + def->st_name, basename(obj->path),
695 (void *)target, basename(defobj->path));
698 * Write the new contents for the jmpslot. Note that depending on
699 * architecture, the value which we need to return back to the
700 * lazy binding trampoline may or may not be the target
701 * address. The value returned from reloc_jmpslot() is the value
702 * that the trampoline needs.
704 target = reloc_jmpslot(where, target, defobj, obj, rel);
705 lock_release(rtld_bind_lock, &lockstate);
710 * Error reporting function. Use it like printf. If formats the message
711 * into a buffer, and sets things up so that the next call to dlerror()
712 * will return the message.
715 _rtld_error(const char *fmt, ...)
717 static char buf[512];
721 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
727 * Return a dynamically-allocated copy of the current error message, if any.
732 return error_message == NULL ? NULL : xstrdup(error_message);
736 * Restore the current error message from a copy which was previously saved
737 * by errmsg_save(). The copy is freed.
740 errmsg_restore(char *saved_msg)
742 if (saved_msg == NULL)
743 error_message = NULL;
745 _rtld_error("%s", saved_msg);
751 basename(const char *name)
753 const char *p = strrchr(name, '/');
754 return p != NULL ? p + 1 : name;
757 static struct utsname uts;
760 origin_subst_one(char *real, const char *kw, const char *subst,
763 char *p, *p1, *res, *resp;
764 int subst_len, kw_len, subst_count, old_len, new_len;
769 * First, count the number of the keyword occurences, to
770 * preallocate the final string.
772 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
779 * If the keyword is not found, just return.
781 if (subst_count == 0)
782 return (may_free ? real : xstrdup(real));
785 * There is indeed something to substitute. Calculate the
786 * length of the resulting string, and allocate it.
788 subst_len = strlen(subst);
789 old_len = strlen(real);
790 new_len = old_len + (subst_len - kw_len) * subst_count;
791 res = xmalloc(new_len + 1);
794 * Now, execute the substitution loop.
796 for (p = real, resp = res, *resp = '\0';;) {
799 /* Copy the prefix before keyword. */
800 memcpy(resp, p, p1 - p);
802 /* Keyword replacement. */
803 memcpy(resp, subst, subst_len);
811 /* Copy to the end of string and finish. */
819 origin_subst(char *real, const char *origin_path)
821 char *res1, *res2, *res3, *res4;
823 if (uts.sysname[0] == '\0') {
824 if (uname(&uts) != 0) {
825 _rtld_error("utsname failed: %d", errno);
829 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
830 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
831 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
832 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
839 const char *msg = dlerror();
843 rtld_fdputstr(STDERR_FILENO, msg);
844 rtld_fdputchar(STDERR_FILENO, '\n');
849 * Process a shared object's DYNAMIC section, and save the important
850 * information in its Obj_Entry structure.
853 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
854 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
857 Needed_Entry **needed_tail = &obj->needed;
858 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
859 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
860 const Elf_Hashelt *hashtab;
861 const Elf32_Word *hashval;
862 Elf32_Word bkt, nmaskwords;
865 int plttype = DT_REL;
871 obj->bind_now = false;
872 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
873 switch (dynp->d_tag) {
876 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
880 obj->relsize = dynp->d_un.d_val;
884 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
888 obj->pltrel = (const Elf_Rel *)
889 (obj->relocbase + dynp->d_un.d_ptr);
893 obj->pltrelsize = dynp->d_un.d_val;
897 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
901 obj->relasize = dynp->d_un.d_val;
905 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
909 plttype = dynp->d_un.d_val;
910 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
914 obj->symtab = (const Elf_Sym *)
915 (obj->relocbase + dynp->d_un.d_ptr);
919 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
923 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
927 obj->strsize = dynp->d_un.d_val;
931 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
936 obj->verneednum = dynp->d_un.d_val;
940 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
945 obj->verdefnum = dynp->d_un.d_val;
949 obj->versyms = (const Elf_Versym *)(obj->relocbase +
955 hashtab = (const Elf_Hashelt *)(obj->relocbase +
957 obj->nbuckets = hashtab[0];
958 obj->nchains = hashtab[1];
959 obj->buckets = hashtab + 2;
960 obj->chains = obj->buckets + obj->nbuckets;
961 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
962 obj->buckets != NULL;
968 hashtab = (const Elf_Hashelt *)(obj->relocbase +
970 obj->nbuckets_gnu = hashtab[0];
971 obj->symndx_gnu = hashtab[1];
972 nmaskwords = hashtab[2];
973 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
974 /* Number of bitmask words is required to be power of 2 */
975 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
976 obj->maskwords_bm_gnu = nmaskwords - 1;
977 obj->shift2_gnu = hashtab[3];
978 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
979 obj->buckets_gnu = hashtab + 4 + bloom_size32;
980 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
982 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
983 obj->buckets_gnu != NULL;
989 Needed_Entry *nep = NEW(Needed_Entry);
990 nep->name = dynp->d_un.d_val;
995 needed_tail = &nep->next;
1001 Needed_Entry *nep = NEW(Needed_Entry);
1002 nep->name = dynp->d_un.d_val;
1006 *needed_filtees_tail = nep;
1007 needed_filtees_tail = &nep->next;
1013 Needed_Entry *nep = NEW(Needed_Entry);
1014 nep->name = dynp->d_un.d_val;
1018 *needed_aux_filtees_tail = nep;
1019 needed_aux_filtees_tail = &nep->next;
1024 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1028 obj->textrel = true;
1032 obj->symbolic = true;
1037 * We have to wait until later to process this, because we
1038 * might not have gotten the address of the string table yet.
1048 *dyn_runpath = dynp;
1052 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1055 case DT_PREINIT_ARRAY:
1056 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1059 case DT_PREINIT_ARRAYSZ:
1060 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1064 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1067 case DT_INIT_ARRAYSZ:
1068 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1072 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1076 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1079 case DT_FINI_ARRAYSZ:
1080 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1084 * Don't process DT_DEBUG on MIPS as the dynamic section
1085 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1090 /* XXX - not implemented yet */
1092 dbg("Filling in DT_DEBUG entry");
1093 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1098 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1099 obj->z_origin = true;
1100 if (dynp->d_un.d_val & DF_SYMBOLIC)
1101 obj->symbolic = true;
1102 if (dynp->d_un.d_val & DF_TEXTREL)
1103 obj->textrel = true;
1104 if (dynp->d_un.d_val & DF_BIND_NOW)
1105 obj->bind_now = true;
1106 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1110 case DT_MIPS_LOCAL_GOTNO:
1111 obj->local_gotno = dynp->d_un.d_val;
1114 case DT_MIPS_SYMTABNO:
1115 obj->symtabno = dynp->d_un.d_val;
1118 case DT_MIPS_GOTSYM:
1119 obj->gotsym = dynp->d_un.d_val;
1122 case DT_MIPS_RLD_MAP:
1125 dbg("Filling in DT_DEBUG entry");
1126 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1132 if (dynp->d_un.d_val & DF_1_NOOPEN)
1133 obj->z_noopen = true;
1134 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1135 obj->z_origin = true;
1136 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1138 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1139 obj->bind_now = true;
1140 if (dynp->d_un.d_val & DF_1_NODELETE)
1141 obj->z_nodelete = true;
1142 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1143 obj->z_loadfltr = true;
1144 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1145 obj->z_interpose = true;
1146 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1147 obj->z_nodeflib = true;
1152 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1159 obj->traced = false;
1161 if (plttype == DT_RELA) {
1162 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1164 obj->pltrelasize = obj->pltrelsize;
1165 obj->pltrelsize = 0;
1168 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1169 if (obj->valid_hash_sysv)
1170 obj->dynsymcount = obj->nchains;
1171 else if (obj->valid_hash_gnu) {
1172 obj->dynsymcount = 0;
1173 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1174 if (obj->buckets_gnu[bkt] == 0)
1176 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1179 while ((*hashval++ & 1u) == 0);
1181 obj->dynsymcount += obj->symndx_gnu;
1186 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1187 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1190 if (obj->z_origin && obj->origin_path == NULL) {
1191 obj->origin_path = xmalloc(PATH_MAX);
1192 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1196 if (dyn_runpath != NULL) {
1197 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1199 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1201 else if (dyn_rpath != NULL) {
1202 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1204 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1207 if (dyn_soname != NULL)
1208 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1212 digest_dynamic(Obj_Entry *obj, int early)
1214 const Elf_Dyn *dyn_rpath;
1215 const Elf_Dyn *dyn_soname;
1216 const Elf_Dyn *dyn_runpath;
1218 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1219 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1223 * Process a shared object's program header. This is used only for the
1224 * main program, when the kernel has already loaded the main program
1225 * into memory before calling the dynamic linker. It creates and
1226 * returns an Obj_Entry structure.
1229 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1232 const Elf_Phdr *phlimit = phdr + phnum;
1234 Elf_Addr note_start, note_end;
1238 for (ph = phdr; ph < phlimit; ph++) {
1239 if (ph->p_type != PT_PHDR)
1243 obj->phsize = ph->p_memsz;
1244 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1248 obj->stack_flags = PF_X | PF_R | PF_W;
1250 for (ph = phdr; ph < phlimit; ph++) {
1251 switch (ph->p_type) {
1254 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1258 if (nsegs == 0) { /* First load segment */
1259 obj->vaddrbase = trunc_page(ph->p_vaddr);
1260 obj->mapbase = obj->vaddrbase + obj->relocbase;
1261 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1263 } else { /* Last load segment */
1264 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1271 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1276 obj->tlssize = ph->p_memsz;
1277 obj->tlsalign = ph->p_align;
1278 obj->tlsinitsize = ph->p_filesz;
1279 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1283 obj->stack_flags = ph->p_flags;
1287 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1288 obj->relro_size = round_page(ph->p_memsz);
1292 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1293 note_end = note_start + ph->p_filesz;
1294 digest_notes(obj, note_start, note_end);
1299 _rtld_error("%s: too few PT_LOAD segments", path);
1308 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1310 const Elf_Note *note;
1311 const char *note_name;
1314 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1315 note = (const Elf_Note *)((const char *)(note + 1) +
1316 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1317 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1318 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1319 note->n_descsz != sizeof(int32_t))
1321 if (note->n_type != ABI_NOTETYPE &&
1322 note->n_type != CRT_NOINIT_NOTETYPE)
1324 note_name = (const char *)(note + 1);
1325 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1326 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1328 switch (note->n_type) {
1330 /* FreeBSD osrel note */
1331 p = (uintptr_t)(note + 1);
1332 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1333 obj->osrel = *(const int32_t *)(p);
1334 dbg("note osrel %d", obj->osrel);
1336 case CRT_NOINIT_NOTETYPE:
1337 /* FreeBSD 'crt does not call init' note */
1338 obj->crt_no_init = true;
1339 dbg("note crt_no_init");
1346 dlcheck(void *handle)
1350 for (obj = obj_list; obj != NULL; obj = obj->next)
1351 if (obj == (Obj_Entry *) handle)
1354 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1355 _rtld_error("Invalid shared object handle %p", handle);
1362 * If the given object is already in the donelist, return true. Otherwise
1363 * add the object to the list and return false.
1366 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1370 for (i = 0; i < dlp->num_used; i++)
1371 if (dlp->objs[i] == obj)
1374 * Our donelist allocation should always be sufficient. But if
1375 * our threads locking isn't working properly, more shared objects
1376 * could have been loaded since we allocated the list. That should
1377 * never happen, but we'll handle it properly just in case it does.
1379 if (dlp->num_used < dlp->num_alloc)
1380 dlp->objs[dlp->num_used++] = obj;
1385 * Hash function for symbol table lookup. Don't even think about changing
1386 * this. It is specified by the System V ABI.
1389 elf_hash(const char *name)
1391 const unsigned char *p = (const unsigned char *) name;
1392 unsigned long h = 0;
1395 while (*p != '\0') {
1396 h = (h << 4) + *p++;
1397 if ((g = h & 0xf0000000) != 0)
1405 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1406 * unsigned in case it's implemented with a wider type.
1409 gnu_hash(const char *s)
1415 for (c = *s; c != '\0'; c = *++s)
1417 return (h & 0xffffffff);
1421 * Find the library with the given name, and return its full pathname.
1422 * The returned string is dynamically allocated. Generates an error
1423 * message and returns NULL if the library cannot be found.
1425 * If the second argument is non-NULL, then it refers to an already-
1426 * loaded shared object, whose library search path will be searched.
1428 * The search order is:
1429 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1430 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1432 * DT_RUNPATH in the referencing file
1433 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1435 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1437 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1440 find_library(const char *xname, const Obj_Entry *refobj)
1444 bool nodeflib, objgiven;
1446 objgiven = refobj != NULL;
1447 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1448 if (xname[0] != '/' && !trust) {
1449 _rtld_error("Absolute pathname required for shared object \"%s\"",
1453 if (objgiven && refobj->z_origin) {
1454 return (origin_subst(__DECONST(char *, xname),
1455 refobj->origin_path));
1457 return (xstrdup(xname));
1461 if (libmap_disable || !objgiven ||
1462 (name = lm_find(refobj->path, xname)) == NULL)
1463 name = (char *)xname;
1465 dbg(" Searching for \"%s\"", name);
1468 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1469 * back to pre-conforming behaviour if user requested so with
1470 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1473 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1474 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1476 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1477 (pathname = search_library_path(name, gethints(false))) != NULL ||
1478 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1481 nodeflib = objgiven ? refobj->z_nodeflib : false;
1483 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1484 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1485 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1486 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1488 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1489 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1490 (objgiven && !nodeflib &&
1491 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1495 if (objgiven && refobj->path != NULL) {
1496 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1497 name, basename(refobj->path));
1499 _rtld_error("Shared object \"%s\" not found", name);
1505 * Given a symbol number in a referencing object, find the corresponding
1506 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1507 * no definition was found. Returns a pointer to the Obj_Entry of the
1508 * defining object via the reference parameter DEFOBJ_OUT.
1511 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1512 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1513 RtldLockState *lockstate)
1517 const Obj_Entry *defobj;
1523 * If we have already found this symbol, get the information from
1526 if (symnum >= refobj->dynsymcount)
1527 return NULL; /* Bad object */
1528 if (cache != NULL && cache[symnum].sym != NULL) {
1529 *defobj_out = cache[symnum].obj;
1530 return cache[symnum].sym;
1533 ref = refobj->symtab + symnum;
1534 name = refobj->strtab + ref->st_name;
1539 * We don't have to do a full scale lookup if the symbol is local.
1540 * We know it will bind to the instance in this load module; to
1541 * which we already have a pointer (ie ref). By not doing a lookup,
1542 * we not only improve performance, but it also avoids unresolvable
1543 * symbols when local symbols are not in the hash table. This has
1544 * been seen with the ia64 toolchain.
1546 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1547 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1548 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1551 symlook_init(&req, name);
1553 req.ventry = fetch_ventry(refobj, symnum);
1554 req.lockstate = lockstate;
1555 res = symlook_default(&req, refobj);
1558 defobj = req.defobj_out;
1566 * If we found no definition and the reference is weak, treat the
1567 * symbol as having the value zero.
1569 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1575 *defobj_out = defobj;
1576 /* Record the information in the cache to avoid subsequent lookups. */
1577 if (cache != NULL) {
1578 cache[symnum].sym = def;
1579 cache[symnum].obj = defobj;
1582 if (refobj != &obj_rtld)
1583 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1589 * Return the search path from the ldconfig hints file, reading it if
1590 * necessary. If nostdlib is true, then the default search paths are
1591 * not added to result.
1593 * Returns NULL if there are problems with the hints file,
1594 * or if the search path there is empty.
1597 gethints(bool nostdlib)
1599 static char *hints, *filtered_path;
1600 struct elfhints_hdr hdr;
1601 struct fill_search_info_args sargs, hargs;
1602 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1603 struct dl_serpath *SLPpath, *hintpath;
1605 unsigned int SLPndx, hintndx, fndx, fcount;
1610 /* First call, read the hints file */
1611 if (hints == NULL) {
1612 /* Keep from trying again in case the hints file is bad. */
1615 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1617 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1618 hdr.magic != ELFHINTS_MAGIC ||
1623 p = xmalloc(hdr.dirlistlen + 1);
1624 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1625 read(fd, p, hdr.dirlistlen + 1) !=
1626 (ssize_t)hdr.dirlistlen + 1) {
1636 * If caller agreed to receive list which includes the default
1637 * paths, we are done. Otherwise, if we still did not
1638 * calculated filtered result, do it now.
1641 return (hints[0] != '\0' ? hints : NULL);
1642 if (filtered_path != NULL)
1646 * Obtain the list of all configured search paths, and the
1647 * list of the default paths.
1649 * First estimate the size of the results.
1651 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1653 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1656 sargs.request = RTLD_DI_SERINFOSIZE;
1657 sargs.serinfo = &smeta;
1658 hargs.request = RTLD_DI_SERINFOSIZE;
1659 hargs.serinfo = &hmeta;
1661 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1662 path_enumerate(p, fill_search_info, &hargs);
1664 SLPinfo = xmalloc(smeta.dls_size);
1665 hintinfo = xmalloc(hmeta.dls_size);
1668 * Next fetch both sets of paths.
1670 sargs.request = RTLD_DI_SERINFO;
1671 sargs.serinfo = SLPinfo;
1672 sargs.serpath = &SLPinfo->dls_serpath[0];
1673 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1675 hargs.request = RTLD_DI_SERINFO;
1676 hargs.serinfo = hintinfo;
1677 hargs.serpath = &hintinfo->dls_serpath[0];
1678 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1680 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1681 path_enumerate(p, fill_search_info, &hargs);
1684 * Now calculate the difference between two sets, by excluding
1685 * standard paths from the full set.
1689 filtered_path = xmalloc(hdr.dirlistlen + 1);
1690 hintpath = &hintinfo->dls_serpath[0];
1691 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1693 SLPpath = &SLPinfo->dls_serpath[0];
1695 * Check each standard path against current.
1697 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1698 /* matched, skip the path */
1699 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1707 * Not matched against any standard path, add the path
1708 * to result. Separate consequtive paths with ':'.
1711 filtered_path[fndx] = ':';
1715 flen = strlen(hintpath->dls_name);
1716 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1719 filtered_path[fndx] = '\0';
1725 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1729 init_dag(Obj_Entry *root)
1731 const Needed_Entry *needed;
1732 const Objlist_Entry *elm;
1735 if (root->dag_inited)
1737 donelist_init(&donelist);
1739 /* Root object belongs to own DAG. */
1740 objlist_push_tail(&root->dldags, root);
1741 objlist_push_tail(&root->dagmembers, root);
1742 donelist_check(&donelist, root);
1745 * Add dependencies of root object to DAG in breadth order
1746 * by exploiting the fact that each new object get added
1747 * to the tail of the dagmembers list.
1749 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1750 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1751 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1753 objlist_push_tail(&needed->obj->dldags, root);
1754 objlist_push_tail(&root->dagmembers, needed->obj);
1757 root->dag_inited = true;
1761 process_nodelete(Obj_Entry *root)
1763 const Objlist_Entry *elm;
1766 * Walk over object DAG and process every dependent object that
1767 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1768 * which then should have its reference upped separately.
1770 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1771 if (elm->obj != NULL && elm->obj->z_nodelete &&
1772 !elm->obj->ref_nodel) {
1773 dbg("obj %s nodelete", elm->obj->path);
1776 elm->obj->ref_nodel = true;
1781 * Initialize the dynamic linker. The argument is the address at which
1782 * the dynamic linker has been mapped into memory. The primary task of
1783 * this function is to relocate the dynamic linker.
1786 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1788 Obj_Entry objtmp; /* Temporary rtld object */
1789 const Elf_Dyn *dyn_rpath;
1790 const Elf_Dyn *dyn_soname;
1791 const Elf_Dyn *dyn_runpath;
1794 * Conjure up an Obj_Entry structure for the dynamic linker.
1796 * The "path" member can't be initialized yet because string constants
1797 * cannot yet be accessed. Below we will set it correctly.
1799 memset(&objtmp, 0, sizeof(objtmp));
1802 objtmp.mapbase = mapbase;
1804 objtmp.relocbase = mapbase;
1806 if (RTLD_IS_DYNAMIC()) {
1807 objtmp.dynamic = rtld_dynamic(&objtmp);
1808 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1809 assert(objtmp.needed == NULL);
1810 #if !defined(__mips__)
1811 /* MIPS has a bogus DT_TEXTREL. */
1812 assert(!objtmp.textrel);
1816 * Temporarily put the dynamic linker entry into the object list, so
1817 * that symbols can be found.
1820 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1823 /* Initialize the object list. */
1824 obj_tail = &obj_list;
1826 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1827 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1829 if (aux_info[AT_PAGESZ] != NULL)
1830 pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
1831 if (aux_info[AT_OSRELDATE] != NULL)
1832 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1834 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1836 /* Replace the path with a dynamically allocated copy. */
1837 obj_rtld.path = xstrdup(PATH_RTLD);
1839 r_debug.r_brk = r_debug_state;
1840 r_debug.r_state = RT_CONSISTENT;
1844 * Add the init functions from a needed object list (and its recursive
1845 * needed objects) to "list". This is not used directly; it is a helper
1846 * function for initlist_add_objects(). The write lock must be held
1847 * when this function is called.
1850 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1852 /* Recursively process the successor needed objects. */
1853 if (needed->next != NULL)
1854 initlist_add_neededs(needed->next, list);
1856 /* Process the current needed object. */
1857 if (needed->obj != NULL)
1858 initlist_add_objects(needed->obj, &needed->obj->next, list);
1862 * Scan all of the DAGs rooted in the range of objects from "obj" to
1863 * "tail" and add their init functions to "list". This recurses over
1864 * the DAGs and ensure the proper init ordering such that each object's
1865 * needed libraries are initialized before the object itself. At the
1866 * same time, this function adds the objects to the global finalization
1867 * list "list_fini" in the opposite order. The write lock must be
1868 * held when this function is called.
1871 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1874 if (obj->init_scanned || obj->init_done)
1876 obj->init_scanned = true;
1878 /* Recursively process the successor objects. */
1879 if (&obj->next != tail)
1880 initlist_add_objects(obj->next, tail, list);
1882 /* Recursively process the needed objects. */
1883 if (obj->needed != NULL)
1884 initlist_add_neededs(obj->needed, list);
1885 if (obj->needed_filtees != NULL)
1886 initlist_add_neededs(obj->needed_filtees, list);
1887 if (obj->needed_aux_filtees != NULL)
1888 initlist_add_neededs(obj->needed_aux_filtees, list);
1890 /* Add the object to the init list. */
1891 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1892 obj->init_array != (Elf_Addr)NULL)
1893 objlist_push_tail(list, obj);
1895 /* Add the object to the global fini list in the reverse order. */
1896 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1897 && !obj->on_fini_list) {
1898 objlist_push_head(&list_fini, obj);
1899 obj->on_fini_list = true;
1904 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1908 free_needed_filtees(Needed_Entry *n)
1910 Needed_Entry *needed, *needed1;
1912 for (needed = n; needed != NULL; needed = needed->next) {
1913 if (needed->obj != NULL) {
1914 dlclose(needed->obj);
1918 for (needed = n; needed != NULL; needed = needed1) {
1919 needed1 = needed->next;
1925 unload_filtees(Obj_Entry *obj)
1928 free_needed_filtees(obj->needed_filtees);
1929 obj->needed_filtees = NULL;
1930 free_needed_filtees(obj->needed_aux_filtees);
1931 obj->needed_aux_filtees = NULL;
1932 obj->filtees_loaded = false;
1936 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
1937 RtldLockState *lockstate)
1940 for (; needed != NULL; needed = needed->next) {
1941 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1942 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1943 RTLD_LOCAL, lockstate);
1948 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1951 lock_restart_for_upgrade(lockstate);
1952 if (!obj->filtees_loaded) {
1953 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
1954 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
1955 obj->filtees_loaded = true;
1960 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1964 for (; needed != NULL; needed = needed->next) {
1965 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
1966 flags & ~RTLD_LO_NOLOAD);
1967 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1974 * Given a shared object, traverse its list of needed objects, and load
1975 * each of them. Returns 0 on success. Generates an error message and
1976 * returns -1 on failure.
1979 load_needed_objects(Obj_Entry *first, int flags)
1983 for (obj = first; obj != NULL; obj = obj->next) {
1984 if (process_needed(obj, obj->needed, flags) == -1)
1991 load_preload_objects(void)
1993 char *p = ld_preload;
1995 static const char delim[] = " \t:;";
2000 p += strspn(p, delim);
2001 while (*p != '\0') {
2002 size_t len = strcspn(p, delim);
2007 obj = load_object(p, -1, NULL, 0);
2009 return -1; /* XXX - cleanup */
2010 obj->z_interpose = true;
2013 p += strspn(p, delim);
2015 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2020 printable_path(const char *path)
2023 return (path == NULL ? "<unknown>" : path);
2027 * Load a shared object into memory, if it is not already loaded. The
2028 * object may be specified by name or by user-supplied file descriptor
2029 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2032 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2036 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2044 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2045 if (object_match_name(obj, name))
2049 path = find_library(name, refobj);
2056 * If we didn't find a match by pathname, or the name is not
2057 * supplied, open the file and check again by device and inode.
2058 * This avoids false mismatches caused by multiple links or ".."
2061 * To avoid a race, we open the file and use fstat() rather than
2066 if ((fd = open(path, O_RDONLY)) == -1) {
2067 _rtld_error("Cannot open \"%s\"", path);
2074 _rtld_error("Cannot dup fd");
2079 if (fstat(fd, &sb) == -1) {
2080 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2085 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2086 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2088 if (obj != NULL && name != NULL) {
2089 object_add_name(obj, name);
2094 if (flags & RTLD_LO_NOLOAD) {
2100 /* First use of this object, so we must map it in */
2101 obj = do_load_object(fd, name, path, &sb, flags);
2110 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2117 * but first, make sure that environment variables haven't been
2118 * used to circumvent the noexec flag on a filesystem.
2120 if (dangerous_ld_env) {
2121 if (fstatfs(fd, &fs) != 0) {
2122 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2125 if (fs.f_flags & MNT_NOEXEC) {
2126 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2130 dbg("loading \"%s\"", printable_path(path));
2131 obj = map_object(fd, printable_path(path), sbp);
2136 * If DT_SONAME is present in the object, digest_dynamic2 already
2137 * added it to the object names.
2140 object_add_name(obj, name);
2142 digest_dynamic(obj, 0);
2143 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2144 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2145 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2147 dbg("refusing to load non-loadable \"%s\"", obj->path);
2148 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2149 munmap(obj->mapbase, obj->mapsize);
2155 obj_tail = &obj->next;
2158 linkmap_add(obj); /* for GDB & dlinfo() */
2159 max_stack_flags |= obj->stack_flags;
2161 dbg(" %p .. %p: %s", obj->mapbase,
2162 obj->mapbase + obj->mapsize - 1, obj->path);
2164 dbg(" WARNING: %s has impure text", obj->path);
2165 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2172 obj_from_addr(const void *addr)
2176 for (obj = obj_list; obj != NULL; obj = obj->next) {
2177 if (addr < (void *) obj->mapbase)
2179 if (addr < (void *) (obj->mapbase + obj->mapsize))
2188 Elf_Addr *preinit_addr;
2191 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2192 if (preinit_addr == NULL)
2195 for (index = 0; index < obj_main->preinit_array_num; index++) {
2196 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2197 dbg("calling preinit function for %s at %p", obj_main->path,
2198 (void *)preinit_addr[index]);
2199 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2200 0, 0, obj_main->path);
2201 call_init_pointer(obj_main, preinit_addr[index]);
2207 * Call the finalization functions for each of the objects in "list"
2208 * belonging to the DAG of "root" and referenced once. If NULL "root"
2209 * is specified, every finalization function will be called regardless
2210 * of the reference count and the list elements won't be freed. All of
2211 * the objects are expected to have non-NULL fini functions.
2214 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2218 Elf_Addr *fini_addr;
2221 assert(root == NULL || root->refcount == 1);
2224 * Preserve the current error message since a fini function might
2225 * call into the dynamic linker and overwrite it.
2227 saved_msg = errmsg_save();
2229 STAILQ_FOREACH(elm, list, link) {
2230 if (root != NULL && (elm->obj->refcount != 1 ||
2231 objlist_find(&root->dagmembers, elm->obj) == NULL))
2233 /* Remove object from fini list to prevent recursive invocation. */
2234 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2236 * XXX: If a dlopen() call references an object while the
2237 * fini function is in progress, we might end up trying to
2238 * unload the referenced object in dlclose() or the object
2239 * won't be unloaded although its fini function has been
2242 lock_release(rtld_bind_lock, lockstate);
2245 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2246 * When this happens, DT_FINI_ARRAY is processed first.
2248 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2249 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2250 for (index = elm->obj->fini_array_num - 1; index >= 0;
2252 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2253 dbg("calling fini function for %s at %p",
2254 elm->obj->path, (void *)fini_addr[index]);
2255 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2256 (void *)fini_addr[index], 0, 0, elm->obj->path);
2257 call_initfini_pointer(elm->obj, fini_addr[index]);
2261 if (elm->obj->fini != (Elf_Addr)NULL) {
2262 dbg("calling fini function for %s at %p", elm->obj->path,
2263 (void *)elm->obj->fini);
2264 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2265 0, 0, elm->obj->path);
2266 call_initfini_pointer(elm->obj, elm->obj->fini);
2268 wlock_acquire(rtld_bind_lock, lockstate);
2269 /* No need to free anything if process is going down. */
2273 * We must restart the list traversal after every fini call
2274 * because a dlclose() call from the fini function or from
2275 * another thread might have modified the reference counts.
2279 } while (elm != NULL);
2280 errmsg_restore(saved_msg);
2284 * Call the initialization functions for each of the objects in
2285 * "list". All of the objects are expected to have non-NULL init
2289 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2294 Elf_Addr *init_addr;
2298 * Clean init_scanned flag so that objects can be rechecked and
2299 * possibly initialized earlier if any of vectors called below
2300 * cause the change by using dlopen.
2302 for (obj = obj_list; obj != NULL; obj = obj->next)
2303 obj->init_scanned = false;
2306 * Preserve the current error message since an init function might
2307 * call into the dynamic linker and overwrite it.
2309 saved_msg = errmsg_save();
2310 STAILQ_FOREACH(elm, list, link) {
2311 if (elm->obj->init_done) /* Initialized early. */
2314 * Race: other thread might try to use this object before current
2315 * one completes the initilization. Not much can be done here
2316 * without better locking.
2318 elm->obj->init_done = true;
2319 lock_release(rtld_bind_lock, lockstate);
2322 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2323 * When this happens, DT_INIT is processed first.
2325 if (elm->obj->init != (Elf_Addr)NULL) {
2326 dbg("calling init function for %s at %p", elm->obj->path,
2327 (void *)elm->obj->init);
2328 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2329 0, 0, elm->obj->path);
2330 call_initfini_pointer(elm->obj, elm->obj->init);
2332 init_addr = (Elf_Addr *)elm->obj->init_array;
2333 if (init_addr != NULL) {
2334 for (index = 0; index < elm->obj->init_array_num; index++) {
2335 if (init_addr[index] != 0 && init_addr[index] != 1) {
2336 dbg("calling init function for %s at %p", elm->obj->path,
2337 (void *)init_addr[index]);
2338 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2339 (void *)init_addr[index], 0, 0, elm->obj->path);
2340 call_init_pointer(elm->obj, init_addr[index]);
2344 wlock_acquire(rtld_bind_lock, lockstate);
2346 errmsg_restore(saved_msg);
2350 objlist_clear(Objlist *list)
2354 while (!STAILQ_EMPTY(list)) {
2355 elm = STAILQ_FIRST(list);
2356 STAILQ_REMOVE_HEAD(list, link);
2361 static Objlist_Entry *
2362 objlist_find(Objlist *list, const Obj_Entry *obj)
2366 STAILQ_FOREACH(elm, list, link)
2367 if (elm->obj == obj)
2373 objlist_init(Objlist *list)
2379 objlist_push_head(Objlist *list, Obj_Entry *obj)
2383 elm = NEW(Objlist_Entry);
2385 STAILQ_INSERT_HEAD(list, elm, link);
2389 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2393 elm = NEW(Objlist_Entry);
2395 STAILQ_INSERT_TAIL(list, elm, link);
2399 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2401 Objlist_Entry *elm, *listelm;
2403 STAILQ_FOREACH(listelm, list, link) {
2404 if (listelm->obj == listobj)
2407 elm = NEW(Objlist_Entry);
2409 if (listelm != NULL)
2410 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2412 STAILQ_INSERT_TAIL(list, elm, link);
2416 objlist_remove(Objlist *list, Obj_Entry *obj)
2420 if ((elm = objlist_find(list, obj)) != NULL) {
2421 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2427 * Relocate dag rooted in the specified object.
2428 * Returns 0 on success, or -1 on failure.
2432 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2433 int flags, RtldLockState *lockstate)
2439 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2440 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2449 * Relocate single object.
2450 * Returns 0 on success, or -1 on failure.
2453 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2454 int flags, RtldLockState *lockstate)
2459 obj->relocated = true;
2461 dbg("relocating \"%s\"", obj->path);
2463 if (obj->symtab == NULL || obj->strtab == NULL ||
2464 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2465 _rtld_error("%s: Shared object has no run-time symbol table",
2471 /* There are relocations to the write-protected text segment. */
2472 if (mprotect(obj->mapbase, obj->textsize,
2473 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2474 _rtld_error("%s: Cannot write-enable text segment: %s",
2475 obj->path, rtld_strerror(errno));
2480 /* Process the non-PLT relocations. */
2481 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2484 if (obj->textrel) { /* Re-protected the text segment. */
2485 if (mprotect(obj->mapbase, obj->textsize,
2486 PROT_READ|PROT_EXEC) == -1) {
2487 _rtld_error("%s: Cannot write-protect text segment: %s",
2488 obj->path, rtld_strerror(errno));
2494 /* Set the special PLT or GOT entries. */
2497 /* Process the PLT relocations. */
2498 if (reloc_plt(obj) == -1)
2500 /* Relocate the jump slots if we are doing immediate binding. */
2501 if (obj->bind_now || bind_now)
2502 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2505 if (obj->relro_size > 0) {
2506 if (mprotect(obj->relro_page, obj->relro_size,
2508 _rtld_error("%s: Cannot enforce relro protection: %s",
2509 obj->path, rtld_strerror(errno));
2515 * Set up the magic number and version in the Obj_Entry. These
2516 * were checked in the crt1.o from the original ElfKit, so we
2517 * set them for backward compatibility.
2519 obj->magic = RTLD_MAGIC;
2520 obj->version = RTLD_VERSION;
2526 * Relocate newly-loaded shared objects. The argument is a pointer to
2527 * the Obj_Entry for the first such object. All objects from the first
2528 * to the end of the list of objects are relocated. Returns 0 on success,
2532 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2533 int flags, RtldLockState *lockstate)
2538 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2539 error = relocate_object(obj, bind_now, rtldobj, flags,
2548 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2549 * referencing STT_GNU_IFUNC symbols is postponed till the other
2550 * relocations are done. The indirect functions specified as
2551 * ifunc are allowed to call other symbols, so we need to have
2552 * objects relocated before asking for resolution from indirects.
2554 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2555 * instead of the usual lazy handling of PLT slots. It is
2556 * consistent with how GNU does it.
2559 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2560 RtldLockState *lockstate)
2562 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2564 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2565 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2571 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2572 RtldLockState *lockstate)
2576 for (obj = first; obj != NULL; obj = obj->next) {
2577 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2584 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2585 RtldLockState *lockstate)
2589 STAILQ_FOREACH(elm, list, link) {
2590 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2598 * Cleanup procedure. It will be called (by the atexit mechanism) just
2599 * before the process exits.
2604 RtldLockState lockstate;
2606 wlock_acquire(rtld_bind_lock, &lockstate);
2608 objlist_call_fini(&list_fini, NULL, &lockstate);
2609 /* No need to remove the items from the list, since we are exiting. */
2610 if (!libmap_disable)
2612 lock_release(rtld_bind_lock, &lockstate);
2616 * Iterate over a search path, translate each element, and invoke the
2617 * callback on the result.
2620 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2626 path += strspn(path, ":;");
2627 while (*path != '\0') {
2631 len = strcspn(path, ":;");
2632 trans = lm_findn(NULL, path, len);
2634 res = callback(trans, strlen(trans), arg);
2636 res = callback(path, len, arg);
2642 path += strspn(path, ":;");
2648 struct try_library_args {
2656 try_library_path(const char *dir, size_t dirlen, void *param)
2658 struct try_library_args *arg;
2661 if (*dir == '/' || trust) {
2664 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2667 pathname = arg->buffer;
2668 strncpy(pathname, dir, dirlen);
2669 pathname[dirlen] = '/';
2670 strcpy(pathname + dirlen + 1, arg->name);
2672 dbg(" Trying \"%s\"", pathname);
2673 if (access(pathname, F_OK) == 0) { /* We found it */
2674 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2675 strcpy(pathname, arg->buffer);
2683 search_library_path(const char *name, const char *path)
2686 struct try_library_args arg;
2692 arg.namelen = strlen(name);
2693 arg.buffer = xmalloc(PATH_MAX);
2694 arg.buflen = PATH_MAX;
2696 p = path_enumerate(path, try_library_path, &arg);
2704 dlclose(void *handle)
2707 RtldLockState lockstate;
2709 wlock_acquire(rtld_bind_lock, &lockstate);
2710 root = dlcheck(handle);
2712 lock_release(rtld_bind_lock, &lockstate);
2715 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2718 /* Unreference the object and its dependencies. */
2719 root->dl_refcount--;
2721 if (root->refcount == 1) {
2723 * The object will be no longer referenced, so we must unload it.
2724 * First, call the fini functions.
2726 objlist_call_fini(&list_fini, root, &lockstate);
2730 /* Finish cleaning up the newly-unreferenced objects. */
2731 GDB_STATE(RT_DELETE,&root->linkmap);
2732 unload_object(root);
2733 GDB_STATE(RT_CONSISTENT,NULL);
2737 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2738 lock_release(rtld_bind_lock, &lockstate);
2745 char *msg = error_message;
2746 error_message = NULL;
2751 * This function is deprecated and has no effect.
2754 dllockinit(void *context,
2755 void *(*lock_create)(void *context),
2756 void (*rlock_acquire)(void *lock),
2757 void (*wlock_acquire)(void *lock),
2758 void (*lock_release)(void *lock),
2759 void (*lock_destroy)(void *lock),
2760 void (*context_destroy)(void *context))
2762 static void *cur_context;
2763 static void (*cur_context_destroy)(void *);
2765 /* Just destroy the context from the previous call, if necessary. */
2766 if (cur_context_destroy != NULL)
2767 cur_context_destroy(cur_context);
2768 cur_context = context;
2769 cur_context_destroy = context_destroy;
2773 dlopen(const char *name, int mode)
2776 return (rtld_dlopen(name, -1, mode));
2780 fdlopen(int fd, int mode)
2783 return (rtld_dlopen(NULL, fd, mode));
2787 rtld_dlopen(const char *name, int fd, int mode)
2789 RtldLockState lockstate;
2792 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2793 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2794 if (ld_tracing != NULL) {
2795 rlock_acquire(rtld_bind_lock, &lockstate);
2796 if (sigsetjmp(lockstate.env, 0) != 0)
2797 lock_upgrade(rtld_bind_lock, &lockstate);
2798 environ = (char **)*get_program_var_addr("environ", &lockstate);
2799 lock_release(rtld_bind_lock, &lockstate);
2801 lo_flags = RTLD_LO_DLOPEN;
2802 if (mode & RTLD_NODELETE)
2803 lo_flags |= RTLD_LO_NODELETE;
2804 if (mode & RTLD_NOLOAD)
2805 lo_flags |= RTLD_LO_NOLOAD;
2806 if (ld_tracing != NULL)
2807 lo_flags |= RTLD_LO_TRACE;
2809 return (dlopen_object(name, fd, obj_main, lo_flags,
2810 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2814 dlopen_cleanup(Obj_Entry *obj)
2819 if (obj->refcount == 0)
2824 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2825 int mode, RtldLockState *lockstate)
2827 Obj_Entry **old_obj_tail;
2830 RtldLockState mlockstate;
2833 objlist_init(&initlist);
2835 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2836 wlock_acquire(rtld_bind_lock, &mlockstate);
2837 lockstate = &mlockstate;
2839 GDB_STATE(RT_ADD,NULL);
2841 old_obj_tail = obj_tail;
2843 if (name == NULL && fd == -1) {
2847 obj = load_object(name, fd, refobj, lo_flags);
2852 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2853 objlist_push_tail(&list_global, obj);
2854 if (*old_obj_tail != NULL) { /* We loaded something new. */
2855 assert(*old_obj_tail == obj);
2856 result = load_needed_objects(obj,
2857 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2861 result = rtld_verify_versions(&obj->dagmembers);
2862 if (result != -1 && ld_tracing)
2864 if (result == -1 || relocate_object_dag(obj,
2865 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2866 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2868 dlopen_cleanup(obj);
2870 } else if (lo_flags & RTLD_LO_EARLY) {
2872 * Do not call the init functions for early loaded
2873 * filtees. The image is still not initialized enough
2876 * Our object is found by the global object list and
2877 * will be ordered among all init calls done right
2878 * before transferring control to main.
2881 /* Make list of init functions to call. */
2882 initlist_add_objects(obj, &obj->next, &initlist);
2885 * Process all no_delete objects here, given them own
2886 * DAGs to prevent their dependencies from being unloaded.
2887 * This has to be done after we have loaded all of the
2888 * dependencies, so that we do not miss any.
2891 process_nodelete(obj);
2894 * Bump the reference counts for objects on this DAG. If
2895 * this is the first dlopen() call for the object that was
2896 * already loaded as a dependency, initialize the dag
2902 if ((lo_flags & RTLD_LO_TRACE) != 0)
2905 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2906 obj->z_nodelete) && !obj->ref_nodel) {
2907 dbg("obj %s nodelete", obj->path);
2909 obj->z_nodelete = obj->ref_nodel = true;
2913 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2915 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2917 if (!(lo_flags & RTLD_LO_EARLY)) {
2918 map_stacks_exec(lockstate);
2921 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2922 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2924 objlist_clear(&initlist);
2925 dlopen_cleanup(obj);
2926 if (lockstate == &mlockstate)
2927 lock_release(rtld_bind_lock, lockstate);
2931 if (!(lo_flags & RTLD_LO_EARLY)) {
2932 /* Call the init functions. */
2933 objlist_call_init(&initlist, lockstate);
2935 objlist_clear(&initlist);
2936 if (lockstate == &mlockstate)
2937 lock_release(rtld_bind_lock, lockstate);
2940 trace_loaded_objects(obj);
2941 if (lockstate == &mlockstate)
2942 lock_release(rtld_bind_lock, lockstate);
2947 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2951 const Obj_Entry *obj, *defobj;
2954 RtldLockState lockstate;
2962 symlook_init(&req, name);
2964 req.flags = flags | SYMLOOK_IN_PLT;
2965 req.lockstate = &lockstate;
2967 rlock_acquire(rtld_bind_lock, &lockstate);
2968 if (sigsetjmp(lockstate.env, 0) != 0)
2969 lock_upgrade(rtld_bind_lock, &lockstate);
2970 if (handle == NULL || handle == RTLD_NEXT ||
2971 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2973 if ((obj = obj_from_addr(retaddr)) == NULL) {
2974 _rtld_error("Cannot determine caller's shared object");
2975 lock_release(rtld_bind_lock, &lockstate);
2978 if (handle == NULL) { /* Just the caller's shared object. */
2979 res = symlook_obj(&req, obj);
2982 defobj = req.defobj_out;
2984 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2985 handle == RTLD_SELF) { /* ... caller included */
2986 if (handle == RTLD_NEXT)
2988 for (; obj != NULL; obj = obj->next) {
2989 res = symlook_obj(&req, obj);
2992 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2994 defobj = req.defobj_out;
2995 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3001 * Search the dynamic linker itself, and possibly resolve the
3002 * symbol from there. This is how the application links to
3003 * dynamic linker services such as dlopen.
3005 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3006 res = symlook_obj(&req, &obj_rtld);
3009 defobj = req.defobj_out;
3013 assert(handle == RTLD_DEFAULT);
3014 res = symlook_default(&req, obj);
3016 defobj = req.defobj_out;
3021 if ((obj = dlcheck(handle)) == NULL) {
3022 lock_release(rtld_bind_lock, &lockstate);
3026 donelist_init(&donelist);
3027 if (obj->mainprog) {
3028 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3029 res = symlook_global(&req, &donelist);
3032 defobj = req.defobj_out;
3035 * Search the dynamic linker itself, and possibly resolve the
3036 * symbol from there. This is how the application links to
3037 * dynamic linker services such as dlopen.
3039 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3040 res = symlook_obj(&req, &obj_rtld);
3043 defobj = req.defobj_out;
3048 /* Search the whole DAG rooted at the given object. */
3049 res = symlook_list(&req, &obj->dagmembers, &donelist);
3052 defobj = req.defobj_out;
3058 lock_release(rtld_bind_lock, &lockstate);
3061 * The value required by the caller is derived from the value
3062 * of the symbol. For the ia64 architecture, we need to
3063 * construct a function descriptor which the caller can use to
3064 * call the function with the right 'gp' value. For other
3065 * architectures and for non-functions, the value is simply
3066 * the relocated value of the symbol.
3068 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3069 return (make_function_pointer(def, defobj));
3070 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3071 return (rtld_resolve_ifunc(defobj, def));
3072 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3074 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3076 ti.ti_module = defobj->tlsindex;
3077 ti.ti_offset = def->st_value;
3078 return (__tls_get_addr(&ti));
3081 return (defobj->relocbase + def->st_value);
3084 _rtld_error("Undefined symbol \"%s\"", name);
3085 lock_release(rtld_bind_lock, &lockstate);
3090 dlsym(void *handle, const char *name)
3092 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3097 dlfunc(void *handle, const char *name)
3104 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3110 dlvsym(void *handle, const char *name, const char *version)
3114 ventry.name = version;
3116 ventry.hash = elf_hash(version);
3118 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3123 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3125 const Obj_Entry *obj;
3126 RtldLockState lockstate;
3128 rlock_acquire(rtld_bind_lock, &lockstate);
3129 obj = obj_from_addr(addr);
3131 _rtld_error("No shared object contains address");
3132 lock_release(rtld_bind_lock, &lockstate);
3135 rtld_fill_dl_phdr_info(obj, phdr_info);
3136 lock_release(rtld_bind_lock, &lockstate);
3141 dladdr(const void *addr, Dl_info *info)
3143 const Obj_Entry *obj;
3146 unsigned long symoffset;
3147 RtldLockState lockstate;
3149 rlock_acquire(rtld_bind_lock, &lockstate);
3150 obj = obj_from_addr(addr);
3152 _rtld_error("No shared object contains address");
3153 lock_release(rtld_bind_lock, &lockstate);
3156 info->dli_fname = obj->path;
3157 info->dli_fbase = obj->mapbase;
3158 info->dli_saddr = (void *)0;
3159 info->dli_sname = NULL;
3162 * Walk the symbol list looking for the symbol whose address is
3163 * closest to the address sent in.
3165 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3166 def = obj->symtab + symoffset;
3169 * For skip the symbol if st_shndx is either SHN_UNDEF or
3172 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3176 * If the symbol is greater than the specified address, or if it
3177 * is further away from addr than the current nearest symbol,
3180 symbol_addr = obj->relocbase + def->st_value;
3181 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3184 /* Update our idea of the nearest symbol. */
3185 info->dli_sname = obj->strtab + def->st_name;
3186 info->dli_saddr = symbol_addr;
3189 if (info->dli_saddr == addr)
3192 lock_release(rtld_bind_lock, &lockstate);
3197 dlinfo(void *handle, int request, void *p)
3199 const Obj_Entry *obj;
3200 RtldLockState lockstate;
3203 rlock_acquire(rtld_bind_lock, &lockstate);
3205 if (handle == NULL || handle == RTLD_SELF) {
3208 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3209 if ((obj = obj_from_addr(retaddr)) == NULL)
3210 _rtld_error("Cannot determine caller's shared object");
3212 obj = dlcheck(handle);
3215 lock_release(rtld_bind_lock, &lockstate);
3221 case RTLD_DI_LINKMAP:
3222 *((struct link_map const **)p) = &obj->linkmap;
3224 case RTLD_DI_ORIGIN:
3225 error = rtld_dirname(obj->path, p);
3228 case RTLD_DI_SERINFOSIZE:
3229 case RTLD_DI_SERINFO:
3230 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3234 _rtld_error("Invalid request %d passed to dlinfo()", request);
3238 lock_release(rtld_bind_lock, &lockstate);
3244 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3247 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3248 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
3249 STAILQ_FIRST(&obj->names)->name : obj->path;
3250 phdr_info->dlpi_phdr = obj->phdr;
3251 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3252 phdr_info->dlpi_tls_modid = obj->tlsindex;
3253 phdr_info->dlpi_tls_data = obj->tlsinit;
3254 phdr_info->dlpi_adds = obj_loads;
3255 phdr_info->dlpi_subs = obj_loads - obj_count;
3259 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3261 struct dl_phdr_info phdr_info;
3262 const Obj_Entry *obj;
3263 RtldLockState bind_lockstate, phdr_lockstate;
3266 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3267 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3271 for (obj = obj_list; obj != NULL; obj = obj->next) {
3272 rtld_fill_dl_phdr_info(obj, &phdr_info);
3273 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3277 lock_release(rtld_bind_lock, &bind_lockstate);
3278 lock_release(rtld_phdr_lock, &phdr_lockstate);
3284 fill_search_info(const char *dir, size_t dirlen, void *param)
3286 struct fill_search_info_args *arg;
3290 if (arg->request == RTLD_DI_SERINFOSIZE) {
3291 arg->serinfo->dls_cnt ++;
3292 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3294 struct dl_serpath *s_entry;
3296 s_entry = arg->serpath;
3297 s_entry->dls_name = arg->strspace;
3298 s_entry->dls_flags = arg->flags;
3300 strncpy(arg->strspace, dir, dirlen);
3301 arg->strspace[dirlen] = '\0';
3303 arg->strspace += dirlen + 1;
3311 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3313 struct dl_serinfo _info;
3314 struct fill_search_info_args args;
3316 args.request = RTLD_DI_SERINFOSIZE;
3317 args.serinfo = &_info;
3319 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3322 path_enumerate(obj->rpath, fill_search_info, &args);
3323 path_enumerate(ld_library_path, fill_search_info, &args);
3324 path_enumerate(obj->runpath, fill_search_info, &args);
3325 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3326 if (!obj->z_nodeflib)
3327 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3330 if (request == RTLD_DI_SERINFOSIZE) {
3331 info->dls_size = _info.dls_size;
3332 info->dls_cnt = _info.dls_cnt;
3336 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3337 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3341 args.request = RTLD_DI_SERINFO;
3342 args.serinfo = info;
3343 args.serpath = &info->dls_serpath[0];
3344 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3346 args.flags = LA_SER_RUNPATH;
3347 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3350 args.flags = LA_SER_LIBPATH;
3351 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3354 args.flags = LA_SER_RUNPATH;
3355 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3358 args.flags = LA_SER_CONFIG;
3359 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3363 args.flags = LA_SER_DEFAULT;
3364 if (!obj->z_nodeflib &&
3365 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3371 rtld_dirname(const char *path, char *bname)
3375 /* Empty or NULL string gets treated as "." */
3376 if (path == NULL || *path == '\0') {
3382 /* Strip trailing slashes */
3383 endp = path + strlen(path) - 1;
3384 while (endp > path && *endp == '/')
3387 /* Find the start of the dir */
3388 while (endp > path && *endp != '/')
3391 /* Either the dir is "/" or there are no slashes */
3393 bname[0] = *endp == '/' ? '/' : '.';
3399 } while (endp > path && *endp == '/');
3402 if (endp - path + 2 > PATH_MAX)
3404 _rtld_error("Filename is too long: %s", path);
3408 strncpy(bname, path, endp - path + 1);
3409 bname[endp - path + 1] = '\0';
3414 rtld_dirname_abs(const char *path, char *base)
3416 char base_rel[PATH_MAX];
3418 if (rtld_dirname(path, base) == -1)
3422 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3423 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3424 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3426 strcpy(base, base_rel);
3431 linkmap_add(Obj_Entry *obj)
3433 struct link_map *l = &obj->linkmap;
3434 struct link_map *prev;
3436 obj->linkmap.l_name = obj->path;
3437 obj->linkmap.l_addr = obj->mapbase;
3438 obj->linkmap.l_ld = obj->dynamic;
3440 /* GDB needs load offset on MIPS to use the symbols */
3441 obj->linkmap.l_offs = obj->relocbase;
3444 if (r_debug.r_map == NULL) {
3450 * Scan to the end of the list, but not past the entry for the
3451 * dynamic linker, which we want to keep at the very end.
3453 for (prev = r_debug.r_map;
3454 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3455 prev = prev->l_next)
3458 /* Link in the new entry. */
3460 l->l_next = prev->l_next;
3461 if (l->l_next != NULL)
3462 l->l_next->l_prev = l;
3467 linkmap_delete(Obj_Entry *obj)
3469 struct link_map *l = &obj->linkmap;
3471 if (l->l_prev == NULL) {
3472 if ((r_debug.r_map = l->l_next) != NULL)
3473 l->l_next->l_prev = NULL;
3477 if ((l->l_prev->l_next = l->l_next) != NULL)
3478 l->l_next->l_prev = l->l_prev;
3482 * Function for the debugger to set a breakpoint on to gain control.
3484 * The two parameters allow the debugger to easily find and determine
3485 * what the runtime loader is doing and to whom it is doing it.
3487 * When the loadhook trap is hit (r_debug_state, set at program
3488 * initialization), the arguments can be found on the stack:
3490 * +8 struct link_map *m
3491 * +4 struct r_debug *rd
3495 r_debug_state(struct r_debug* rd, struct link_map *m)
3498 * The following is a hack to force the compiler to emit calls to
3499 * this function, even when optimizing. If the function is empty,
3500 * the compiler is not obliged to emit any code for calls to it,
3501 * even when marked __noinline. However, gdb depends on those
3504 __asm __volatile("" : : : "memory");
3508 * Get address of the pointer variable in the main program.
3509 * Prefer non-weak symbol over the weak one.
3511 static const void **
3512 get_program_var_addr(const char *name, RtldLockState *lockstate)
3517 symlook_init(&req, name);
3518 req.lockstate = lockstate;
3519 donelist_init(&donelist);
3520 if (symlook_global(&req, &donelist) != 0)
3522 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3523 return ((const void **)make_function_pointer(req.sym_out,
3525 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3526 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3528 return ((const void **)(req.defobj_out->relocbase +
3529 req.sym_out->st_value));
3533 * Set a pointer variable in the main program to the given value. This
3534 * is used to set key variables such as "environ" before any of the
3535 * init functions are called.
3538 set_program_var(const char *name, const void *value)
3542 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3543 dbg("\"%s\": *%p <-- %p", name, addr, value);
3549 * Search the global objects, including dependencies and main object,
3550 * for the given symbol.
3553 symlook_global(SymLook *req, DoneList *donelist)
3556 const Objlist_Entry *elm;
3559 symlook_init_from_req(&req1, req);
3561 /* Search all objects loaded at program start up. */
3562 if (req->defobj_out == NULL ||
3563 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3564 res = symlook_list(&req1, &list_main, donelist);
3565 if (res == 0 && (req->defobj_out == NULL ||
3566 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3567 req->sym_out = req1.sym_out;
3568 req->defobj_out = req1.defobj_out;
3569 assert(req->defobj_out != NULL);
3573 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3574 STAILQ_FOREACH(elm, &list_global, link) {
3575 if (req->defobj_out != NULL &&
3576 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3578 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3579 if (res == 0 && (req->defobj_out == NULL ||
3580 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3581 req->sym_out = req1.sym_out;
3582 req->defobj_out = req1.defobj_out;
3583 assert(req->defobj_out != NULL);
3587 return (req->sym_out != NULL ? 0 : ESRCH);
3591 * Given a symbol name in a referencing object, find the corresponding
3592 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3593 * no definition was found. Returns a pointer to the Obj_Entry of the
3594 * defining object via the reference parameter DEFOBJ_OUT.
3597 symlook_default(SymLook *req, const Obj_Entry *refobj)
3600 const Objlist_Entry *elm;
3604 donelist_init(&donelist);
3605 symlook_init_from_req(&req1, req);
3607 /* Look first in the referencing object if linked symbolically. */
3608 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3609 res = symlook_obj(&req1, refobj);
3611 req->sym_out = req1.sym_out;
3612 req->defobj_out = req1.defobj_out;
3613 assert(req->defobj_out != NULL);
3617 symlook_global(req, &donelist);
3619 /* Search all dlopened DAGs containing the referencing object. */
3620 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3621 if (req->sym_out != NULL &&
3622 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3624 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3625 if (res == 0 && (req->sym_out == NULL ||
3626 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3627 req->sym_out = req1.sym_out;
3628 req->defobj_out = req1.defobj_out;
3629 assert(req->defobj_out != NULL);
3634 * Search the dynamic linker itself, and possibly resolve the
3635 * symbol from there. This is how the application links to
3636 * dynamic linker services such as dlopen.
3638 if (req->sym_out == NULL ||
3639 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3640 res = symlook_obj(&req1, &obj_rtld);
3642 req->sym_out = req1.sym_out;
3643 req->defobj_out = req1.defobj_out;
3644 assert(req->defobj_out != NULL);
3648 return (req->sym_out != NULL ? 0 : ESRCH);
3652 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3655 const Obj_Entry *defobj;
3656 const Objlist_Entry *elm;
3662 STAILQ_FOREACH(elm, objlist, link) {
3663 if (donelist_check(dlp, elm->obj))
3665 symlook_init_from_req(&req1, req);
3666 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3667 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3669 defobj = req1.defobj_out;
3670 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3677 req->defobj_out = defobj;
3684 * Search the chain of DAGS cointed to by the given Needed_Entry
3685 * for a symbol of the given name. Each DAG is scanned completely
3686 * before advancing to the next one. Returns a pointer to the symbol,
3687 * or NULL if no definition was found.
3690 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3693 const Needed_Entry *n;
3694 const Obj_Entry *defobj;
3700 symlook_init_from_req(&req1, req);
3701 for (n = needed; n != NULL; n = n->next) {
3702 if (n->obj == NULL ||
3703 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3705 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3707 defobj = req1.defobj_out;
3708 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3714 req->defobj_out = defobj;
3721 * Search the symbol table of a single shared object for a symbol of
3722 * the given name and version, if requested. Returns a pointer to the
3723 * symbol, or NULL if no definition was found. If the object is
3724 * filter, return filtered symbol from filtee.
3726 * The symbol's hash value is passed in for efficiency reasons; that
3727 * eliminates many recomputations of the hash value.
3730 symlook_obj(SymLook *req, const Obj_Entry *obj)
3734 int flags, res, mres;
3737 * If there is at least one valid hash at this point, we prefer to
3738 * use the faster GNU version if available.
3740 if (obj->valid_hash_gnu)
3741 mres = symlook_obj1_gnu(req, obj);
3742 else if (obj->valid_hash_sysv)
3743 mres = symlook_obj1_sysv(req, obj);
3748 if (obj->needed_filtees != NULL) {
3749 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3750 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3751 donelist_init(&donelist);
3752 symlook_init_from_req(&req1, req);
3753 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3755 req->sym_out = req1.sym_out;
3756 req->defobj_out = req1.defobj_out;
3760 if (obj->needed_aux_filtees != NULL) {
3761 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3762 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3763 donelist_init(&donelist);
3764 symlook_init_from_req(&req1, req);
3765 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3767 req->sym_out = req1.sym_out;
3768 req->defobj_out = req1.defobj_out;
3776 /* Symbol match routine common to both hash functions */
3778 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3779 const unsigned long symnum)
3782 const Elf_Sym *symp;
3785 symp = obj->symtab + symnum;
3786 strp = obj->strtab + symp->st_name;
3788 switch (ELF_ST_TYPE(symp->st_info)) {
3794 if (symp->st_value == 0)
3798 if (symp->st_shndx != SHN_UNDEF)
3801 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3802 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3809 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3812 if (req->ventry == NULL) {
3813 if (obj->versyms != NULL) {
3814 verndx = VER_NDX(obj->versyms[symnum]);
3815 if (verndx > obj->vernum) {
3817 "%s: symbol %s references wrong version %d",
3818 obj->path, obj->strtab + symnum, verndx);
3822 * If we are not called from dlsym (i.e. this
3823 * is a normal relocation from unversioned
3824 * binary), accept the symbol immediately if
3825 * it happens to have first version after this
3826 * shared object became versioned. Otherwise,
3827 * if symbol is versioned and not hidden,
3828 * remember it. If it is the only symbol with
3829 * this name exported by the shared object, it
3830 * will be returned as a match by the calling
3831 * function. If symbol is global (verndx < 2)
3832 * accept it unconditionally.
3834 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3835 verndx == VER_NDX_GIVEN) {
3836 result->sym_out = symp;
3839 else if (verndx >= VER_NDX_GIVEN) {
3840 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3842 if (result->vsymp == NULL)
3843 result->vsymp = symp;
3849 result->sym_out = symp;
3852 if (obj->versyms == NULL) {
3853 if (object_match_name(obj, req->ventry->name)) {
3854 _rtld_error("%s: object %s should provide version %s "
3855 "for symbol %s", obj_rtld.path, obj->path,
3856 req->ventry->name, obj->strtab + symnum);
3860 verndx = VER_NDX(obj->versyms[symnum]);
3861 if (verndx > obj->vernum) {
3862 _rtld_error("%s: symbol %s references wrong version %d",
3863 obj->path, obj->strtab + symnum, verndx);
3866 if (obj->vertab[verndx].hash != req->ventry->hash ||
3867 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3869 * Version does not match. Look if this is a
3870 * global symbol and if it is not hidden. If
3871 * global symbol (verndx < 2) is available,
3872 * use it. Do not return symbol if we are
3873 * called by dlvsym, because dlvsym looks for
3874 * a specific version and default one is not
3875 * what dlvsym wants.
3877 if ((req->flags & SYMLOOK_DLSYM) ||
3878 (verndx >= VER_NDX_GIVEN) ||
3879 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3883 result->sym_out = symp;
3888 * Search for symbol using SysV hash function.
3889 * obj->buckets is known not to be NULL at this point; the test for this was
3890 * performed with the obj->valid_hash_sysv assignment.
3893 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
3895 unsigned long symnum;
3896 Sym_Match_Result matchres;
3898 matchres.sym_out = NULL;
3899 matchres.vsymp = NULL;
3900 matchres.vcount = 0;
3902 for (symnum = obj->buckets[req->hash % obj->nbuckets];
3903 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3904 if (symnum >= obj->nchains)
3905 return (ESRCH); /* Bad object */
3907 if (matched_symbol(req, obj, &matchres, symnum)) {
3908 req->sym_out = matchres.sym_out;
3909 req->defobj_out = obj;
3913 if (matchres.vcount == 1) {
3914 req->sym_out = matchres.vsymp;
3915 req->defobj_out = obj;
3921 /* Search for symbol using GNU hash function */
3923 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
3925 Elf_Addr bloom_word;
3926 const Elf32_Word *hashval;
3928 Sym_Match_Result matchres;
3929 unsigned int h1, h2;
3930 unsigned long symnum;
3932 matchres.sym_out = NULL;
3933 matchres.vsymp = NULL;
3934 matchres.vcount = 0;
3936 /* Pick right bitmask word from Bloom filter array */
3937 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
3938 obj->maskwords_bm_gnu];
3940 /* Calculate modulus word size of gnu hash and its derivative */
3941 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
3942 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
3944 /* Filter out the "definitely not in set" queries */
3945 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
3948 /* Locate hash chain and corresponding value element*/
3949 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
3952 hashval = &obj->chain_zero_gnu[bucket];
3954 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
3955 symnum = hashval - obj->chain_zero_gnu;
3956 if (matched_symbol(req, obj, &matchres, symnum)) {
3957 req->sym_out = matchres.sym_out;
3958 req->defobj_out = obj;
3962 } while ((*hashval++ & 1) == 0);
3963 if (matchres.vcount == 1) {
3964 req->sym_out = matchres.vsymp;
3965 req->defobj_out = obj;
3972 trace_loaded_objects(Obj_Entry *obj)
3974 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3977 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3980 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3981 fmt1 = "\t%o => %p (%x)\n";
3983 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3984 fmt2 = "\t%o (%x)\n";
3986 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
3988 for (; obj; obj = obj->next) {
3989 Needed_Entry *needed;
3993 if (list_containers && obj->needed != NULL)
3994 rtld_printf("%s:\n", obj->path);
3995 for (needed = obj->needed; needed; needed = needed->next) {
3996 if (needed->obj != NULL) {
3997 if (needed->obj->traced && !list_containers)
3999 needed->obj->traced = true;
4000 path = needed->obj->path;
4004 name = (char *)obj->strtab + needed->name;
4005 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4007 fmt = is_lib ? fmt1 : fmt2;
4008 while ((c = *fmt++) != '\0') {
4034 rtld_putstr(main_local);
4037 rtld_putstr(obj_main->path);
4044 rtld_printf("%d", sodp->sod_major);
4047 rtld_printf("%d", sodp->sod_minor);
4054 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4067 * Unload a dlopened object and its dependencies from memory and from
4068 * our data structures. It is assumed that the DAG rooted in the
4069 * object has already been unreferenced, and that the object has a
4070 * reference count of 0.
4073 unload_object(Obj_Entry *root)
4078 assert(root->refcount == 0);
4081 * Pass over the DAG removing unreferenced objects from
4082 * appropriate lists.
4084 unlink_object(root);
4086 /* Unmap all objects that are no longer referenced. */
4087 linkp = &obj_list->next;
4088 while ((obj = *linkp) != NULL) {
4089 if (obj->refcount == 0) {
4090 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4092 dbg("unloading \"%s\"", obj->path);
4093 unload_filtees(root);
4094 munmap(obj->mapbase, obj->mapsize);
4095 linkmap_delete(obj);
4106 unlink_object(Obj_Entry *root)
4110 if (root->refcount == 0) {
4111 /* Remove the object from the RTLD_GLOBAL list. */
4112 objlist_remove(&list_global, root);
4114 /* Remove the object from all objects' DAG lists. */
4115 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4116 objlist_remove(&elm->obj->dldags, root);
4117 if (elm->obj != root)
4118 unlink_object(elm->obj);
4124 ref_dag(Obj_Entry *root)
4128 assert(root->dag_inited);
4129 STAILQ_FOREACH(elm, &root->dagmembers, link)
4130 elm->obj->refcount++;
4134 unref_dag(Obj_Entry *root)
4138 assert(root->dag_inited);
4139 STAILQ_FOREACH(elm, &root->dagmembers, link)
4140 elm->obj->refcount--;
4144 * Common code for MD __tls_get_addr().
4146 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4148 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4150 Elf_Addr *newdtv, *dtv;
4151 RtldLockState lockstate;
4155 /* Check dtv generation in case new modules have arrived */
4156 if (dtv[0] != tls_dtv_generation) {
4157 wlock_acquire(rtld_bind_lock, &lockstate);
4158 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4160 if (to_copy > tls_max_index)
4161 to_copy = tls_max_index;
4162 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4163 newdtv[0] = tls_dtv_generation;
4164 newdtv[1] = tls_max_index;
4166 lock_release(rtld_bind_lock, &lockstate);
4167 dtv = *dtvp = newdtv;
4170 /* Dynamically allocate module TLS if necessary */
4171 if (dtv[index + 1] == 0) {
4172 /* Signal safe, wlock will block out signals. */
4173 wlock_acquire(rtld_bind_lock, &lockstate);
4174 if (!dtv[index + 1])
4175 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4176 lock_release(rtld_bind_lock, &lockstate);
4178 return ((void *)(dtv[index + 1] + offset));
4182 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4187 /* Check dtv generation in case new modules have arrived */
4188 if (__predict_true(dtv[0] == tls_dtv_generation &&
4189 dtv[index + 1] != 0))
4190 return ((void *)(dtv[index + 1] + offset));
4191 return (tls_get_addr_slow(dtvp, index, offset));
4194 #if defined(__arm__) || defined(__ia64__) || defined(__powerpc__)
4197 * Allocate Static TLS using the Variant I method.
4200 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4209 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4212 assert(tcbsize >= TLS_TCB_SIZE);
4213 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4214 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4216 if (oldtcb != NULL) {
4217 memcpy(tls, oldtcb, tls_static_space);
4220 /* Adjust the DTV. */
4222 for (i = 0; i < dtv[1]; i++) {
4223 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4224 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4225 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4229 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4231 dtv[0] = tls_dtv_generation;
4232 dtv[1] = tls_max_index;
4234 for (obj = objs; obj; obj = obj->next) {
4235 if (obj->tlsoffset > 0) {
4236 addr = (Elf_Addr)tls + obj->tlsoffset;
4237 if (obj->tlsinitsize > 0)
4238 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4239 if (obj->tlssize > obj->tlsinitsize)
4240 memset((void*) (addr + obj->tlsinitsize), 0,
4241 obj->tlssize - obj->tlsinitsize);
4242 dtv[obj->tlsindex + 1] = addr;
4251 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4254 Elf_Addr tlsstart, tlsend;
4257 assert(tcbsize >= TLS_TCB_SIZE);
4259 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4260 tlsend = tlsstart + tls_static_space;
4262 dtv = *(Elf_Addr **)tlsstart;
4264 for (i = 0; i < dtvsize; i++) {
4265 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4266 free((void*)dtv[i+2]);
4275 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
4279 * Allocate Static TLS using the Variant II method.
4282 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4285 size_t size, ralign;
4287 Elf_Addr *dtv, *olddtv;
4288 Elf_Addr segbase, oldsegbase, addr;
4292 if (tls_static_max_align > ralign)
4293 ralign = tls_static_max_align;
4294 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4296 assert(tcbsize >= 2*sizeof(Elf_Addr));
4297 tls = malloc_aligned(size, ralign);
4298 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4300 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4301 ((Elf_Addr*)segbase)[0] = segbase;
4302 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4304 dtv[0] = tls_dtv_generation;
4305 dtv[1] = tls_max_index;
4309 * Copy the static TLS block over whole.
4311 oldsegbase = (Elf_Addr) oldtls;
4312 memcpy((void *)(segbase - tls_static_space),
4313 (const void *)(oldsegbase - tls_static_space),
4317 * If any dynamic TLS blocks have been created tls_get_addr(),
4320 olddtv = ((Elf_Addr**)oldsegbase)[1];
4321 for (i = 0; i < olddtv[1]; i++) {
4322 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4323 dtv[i+2] = olddtv[i+2];
4329 * We assume that this block was the one we created with
4330 * allocate_initial_tls().
4332 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4334 for (obj = objs; obj; obj = obj->next) {
4335 if (obj->tlsoffset) {
4336 addr = segbase - obj->tlsoffset;
4337 memset((void*) (addr + obj->tlsinitsize),
4338 0, obj->tlssize - obj->tlsinitsize);
4340 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4341 dtv[obj->tlsindex + 1] = addr;
4346 return (void*) segbase;
4350 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4353 size_t size, ralign;
4355 Elf_Addr tlsstart, tlsend;
4358 * Figure out the size of the initial TLS block so that we can
4359 * find stuff which ___tls_get_addr() allocated dynamically.
4362 if (tls_static_max_align > ralign)
4363 ralign = tls_static_max_align;
4364 size = round(tls_static_space, ralign);
4366 dtv = ((Elf_Addr**)tls)[1];
4368 tlsend = (Elf_Addr) tls;
4369 tlsstart = tlsend - size;
4370 for (i = 0; i < dtvsize; i++) {
4371 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4372 free_aligned((void *)dtv[i + 2]);
4376 free_aligned((void *)tlsstart);
4383 * Allocate TLS block for module with given index.
4386 allocate_module_tls(int index)
4391 for (obj = obj_list; obj; obj = obj->next) {
4392 if (obj->tlsindex == index)
4396 _rtld_error("Can't find module with TLS index %d", index);
4400 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4401 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4402 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4408 allocate_tls_offset(Obj_Entry *obj)
4415 if (obj->tlssize == 0) {
4416 obj->tls_done = true;
4420 if (obj->tlsindex == 1)
4421 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4423 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4424 obj->tlssize, obj->tlsalign);
4427 * If we have already fixed the size of the static TLS block, we
4428 * must stay within that size. When allocating the static TLS, we
4429 * leave a small amount of space spare to be used for dynamically
4430 * loading modules which use static TLS.
4432 if (tls_static_space != 0) {
4433 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4435 } else if (obj->tlsalign > tls_static_max_align) {
4436 tls_static_max_align = obj->tlsalign;
4439 tls_last_offset = obj->tlsoffset = off;
4440 tls_last_size = obj->tlssize;
4441 obj->tls_done = true;
4447 free_tls_offset(Obj_Entry *obj)
4451 * If we were the last thing to allocate out of the static TLS
4452 * block, we give our space back to the 'allocator'. This is a
4453 * simplistic workaround to allow libGL.so.1 to be loaded and
4454 * unloaded multiple times.
4456 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4457 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4458 tls_last_offset -= obj->tlssize;
4464 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4467 RtldLockState lockstate;
4469 wlock_acquire(rtld_bind_lock, &lockstate);
4470 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4471 lock_release(rtld_bind_lock, &lockstate);
4476 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4478 RtldLockState lockstate;
4480 wlock_acquire(rtld_bind_lock, &lockstate);
4481 free_tls(tcb, tcbsize, tcbalign);
4482 lock_release(rtld_bind_lock, &lockstate);
4486 object_add_name(Obj_Entry *obj, const char *name)
4492 entry = malloc(sizeof(Name_Entry) + len);
4494 if (entry != NULL) {
4495 strcpy(entry->name, name);
4496 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4501 object_match_name(const Obj_Entry *obj, const char *name)
4505 STAILQ_FOREACH(entry, &obj->names, link) {
4506 if (strcmp(name, entry->name) == 0)
4513 locate_dependency(const Obj_Entry *obj, const char *name)
4515 const Objlist_Entry *entry;
4516 const Needed_Entry *needed;
4518 STAILQ_FOREACH(entry, &list_main, link) {
4519 if (object_match_name(entry->obj, name))
4523 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4524 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4525 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4527 * If there is DT_NEEDED for the name we are looking for,
4528 * we are all set. Note that object might not be found if
4529 * dependency was not loaded yet, so the function can
4530 * return NULL here. This is expected and handled
4531 * properly by the caller.
4533 return (needed->obj);
4536 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4542 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4543 const Elf_Vernaux *vna)
4545 const Elf_Verdef *vd;
4546 const char *vername;
4548 vername = refobj->strtab + vna->vna_name;
4549 vd = depobj->verdef;
4551 _rtld_error("%s: version %s required by %s not defined",
4552 depobj->path, vername, refobj->path);
4556 if (vd->vd_version != VER_DEF_CURRENT) {
4557 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4558 depobj->path, vd->vd_version);
4561 if (vna->vna_hash == vd->vd_hash) {
4562 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4563 ((char *)vd + vd->vd_aux);
4564 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4567 if (vd->vd_next == 0)
4569 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4571 if (vna->vna_flags & VER_FLG_WEAK)
4573 _rtld_error("%s: version %s required by %s not found",
4574 depobj->path, vername, refobj->path);
4579 rtld_verify_object_versions(Obj_Entry *obj)
4581 const Elf_Verneed *vn;
4582 const Elf_Verdef *vd;
4583 const Elf_Verdaux *vda;
4584 const Elf_Vernaux *vna;
4585 const Obj_Entry *depobj;
4586 int maxvernum, vernum;
4588 if (obj->ver_checked)
4590 obj->ver_checked = true;
4594 * Walk over defined and required version records and figure out
4595 * max index used by any of them. Do very basic sanity checking
4599 while (vn != NULL) {
4600 if (vn->vn_version != VER_NEED_CURRENT) {
4601 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4602 obj->path, vn->vn_version);
4605 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4607 vernum = VER_NEED_IDX(vna->vna_other);
4608 if (vernum > maxvernum)
4610 if (vna->vna_next == 0)
4612 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4614 if (vn->vn_next == 0)
4616 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4620 while (vd != NULL) {
4621 if (vd->vd_version != VER_DEF_CURRENT) {
4622 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4623 obj->path, vd->vd_version);
4626 vernum = VER_DEF_IDX(vd->vd_ndx);
4627 if (vernum > maxvernum)
4629 if (vd->vd_next == 0)
4631 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4638 * Store version information in array indexable by version index.
4639 * Verify that object version requirements are satisfied along the
4642 obj->vernum = maxvernum + 1;
4643 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4646 while (vd != NULL) {
4647 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4648 vernum = VER_DEF_IDX(vd->vd_ndx);
4649 assert(vernum <= maxvernum);
4650 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4651 obj->vertab[vernum].hash = vd->vd_hash;
4652 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4653 obj->vertab[vernum].file = NULL;
4654 obj->vertab[vernum].flags = 0;
4656 if (vd->vd_next == 0)
4658 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4662 while (vn != NULL) {
4663 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4666 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4668 if (check_object_provided_version(obj, depobj, vna))
4670 vernum = VER_NEED_IDX(vna->vna_other);
4671 assert(vernum <= maxvernum);
4672 obj->vertab[vernum].hash = vna->vna_hash;
4673 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4674 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4675 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4676 VER_INFO_HIDDEN : 0;
4677 if (vna->vna_next == 0)
4679 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4681 if (vn->vn_next == 0)
4683 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4689 rtld_verify_versions(const Objlist *objlist)
4691 Objlist_Entry *entry;
4695 STAILQ_FOREACH(entry, objlist, link) {
4697 * Skip dummy objects or objects that have their version requirements
4700 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4702 if (rtld_verify_object_versions(entry->obj) == -1) {
4704 if (ld_tracing == NULL)
4708 if (rc == 0 || ld_tracing != NULL)
4709 rc = rtld_verify_object_versions(&obj_rtld);
4714 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4719 vernum = VER_NDX(obj->versyms[symnum]);
4720 if (vernum >= obj->vernum) {
4721 _rtld_error("%s: symbol %s has wrong verneed value %d",
4722 obj->path, obj->strtab + symnum, vernum);
4723 } else if (obj->vertab[vernum].hash != 0) {
4724 return &obj->vertab[vernum];
4731 _rtld_get_stack_prot(void)
4734 return (stack_prot);
4738 map_stacks_exec(RtldLockState *lockstate)
4740 void (*thr_map_stacks_exec)(void);
4742 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4744 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4745 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4746 if (thr_map_stacks_exec != NULL) {
4747 stack_prot |= PROT_EXEC;
4748 thr_map_stacks_exec();
4753 symlook_init(SymLook *dst, const char *name)
4756 bzero(dst, sizeof(*dst));
4758 dst->hash = elf_hash(name);
4759 dst->hash_gnu = gnu_hash(name);
4763 symlook_init_from_req(SymLook *dst, const SymLook *src)
4766 dst->name = src->name;
4767 dst->hash = src->hash;
4768 dst->hash_gnu = src->hash_gnu;
4769 dst->ventry = src->ventry;
4770 dst->flags = src->flags;
4771 dst->defobj_out = NULL;
4772 dst->sym_out = NULL;
4773 dst->lockstate = src->lockstate;
4777 * Overrides for libc_pic-provided functions.
4781 __getosreldate(void)
4791 oid[1] = KERN_OSRELDATE;
4793 len = sizeof(osrel);
4794 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4795 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4807 void (*__cleanup)(void);
4808 int __isthreaded = 0;
4809 int _thread_autoinit_dummy_decl = 1;
4812 * No unresolved symbols for rtld.
4815 __pthread_cxa_finalize(struct dl_phdr_info *a)
4820 __stack_chk_fail(void)
4823 _rtld_error("stack overflow detected; terminated");
4826 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
4832 _rtld_error("buffer overflow detected; terminated");
4837 rtld_strerror(int errnum)
4840 if (errnum < 0 || errnum >= sys_nerr)
4841 return ("Unknown error");
4842 return (sys_errlist[errnum]);