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 digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
82 const Elf_Dyn **, const Elf_Dyn **);
83 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
85 static void digest_dynamic(Obj_Entry *, int);
86 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
87 static Obj_Entry *dlcheck(void *);
88 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
89 int lo_flags, int mode, RtldLockState *lockstate);
90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
92 static bool donelist_check(DoneList *, const Obj_Entry *);
93 static void errmsg_restore(char *);
94 static char *errmsg_save(void);
95 static void *fill_search_info(const char *, size_t, void *);
96 static char *find_library(const char *, const Obj_Entry *);
97 static const char *gethints(bool);
98 static void init_dag(Obj_Entry *);
99 static void init_pagesizes(Elf_Auxinfo **aux_info);
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(Obj_Entry *, char *, const char *,
151 static char *origin_subst(Obj_Entry *, char *);
152 static bool obj_resolve_origin(Obj_Entry *obj);
153 static void preinit_main(void);
154 static int rtld_verify_versions(const Objlist *);
155 static int rtld_verify_object_versions(Obj_Entry *);
156 static void object_add_name(Obj_Entry *, const char *);
157 static int object_match_name(const Obj_Entry *, const char *);
158 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
159 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
160 struct dl_phdr_info *phdr_info);
161 static uint32_t gnu_hash(const char *);
162 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
163 const unsigned long);
165 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
166 void _r_debug_postinit(struct link_map *) __noinline __exported;
171 static char *error_message; /* Message for dlerror(), or NULL */
172 struct r_debug r_debug __exported; /* for GDB; */
173 static bool libmap_disable; /* Disable libmap */
174 static bool ld_loadfltr; /* Immediate filters processing */
175 static char *libmap_override; /* Maps to use in addition to libmap.conf */
176 static bool trust; /* False for setuid and setgid programs */
177 static bool dangerous_ld_env; /* True if environment variables have been
178 used to affect the libraries loaded */
179 static char *ld_bind_now; /* Environment variable for immediate binding */
180 static char *ld_debug; /* Environment variable for debugging */
181 static char *ld_library_path; /* Environment variable for search path */
182 static char *ld_preload; /* Environment variable for libraries to
184 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
185 static char *ld_tracing; /* Called from ldd to print libs */
186 static char *ld_utrace; /* Use utrace() to log events. */
187 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
188 static Obj_Entry **obj_tail; /* Link field of last object in list */
189 static Obj_Entry *obj_main; /* The main program shared object */
190 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
191 static unsigned int obj_count; /* Number of objects in obj_list */
192 static unsigned int obj_loads; /* Number of objects in obj_list */
194 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
195 STAILQ_HEAD_INITIALIZER(list_global);
196 static Objlist list_main = /* Objects loaded at program startup */
197 STAILQ_HEAD_INITIALIZER(list_main);
198 static Objlist list_fini = /* Objects needing fini() calls */
199 STAILQ_HEAD_INITIALIZER(list_fini);
201 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
203 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
205 extern Elf_Dyn _DYNAMIC;
206 #pragma weak _DYNAMIC
207 #ifndef RTLD_IS_DYNAMIC
208 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
211 int dlclose(void *) __exported;
212 char *dlerror(void) __exported;
213 void *dlopen(const char *, int) __exported;
214 void *fdlopen(int, int) __exported;
215 void *dlsym(void *, const char *) __exported;
216 dlfunc_t dlfunc(void *, const char *) __exported;
217 void *dlvsym(void *, const char *, const char *) __exported;
218 int dladdr(const void *, Dl_info *) __exported;
219 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
220 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
221 int dlinfo(void *, int , void *) __exported;
222 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
223 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
224 int _rtld_get_stack_prot(void) __exported;
225 int _rtld_is_dlopened(void *) __exported;
226 void _rtld_error(const char *, ...) __exported;
228 int npagesizes, osreldate;
231 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
233 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
234 static int max_stack_flags;
237 * Global declarations normally provided by crt1. The dynamic linker is
238 * not built with crt1, so we have to provide them ourselves.
244 * Used to pass argc, argv to init functions.
250 * Globals to control TLS allocation.
252 size_t tls_last_offset; /* Static TLS offset of last module */
253 size_t tls_last_size; /* Static TLS size of last module */
254 size_t tls_static_space; /* Static TLS space allocated */
255 size_t tls_static_max_align;
256 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
257 int tls_max_index = 1; /* Largest module index allocated */
259 bool ld_library_path_rpath = false;
262 * Fill in a DoneList with an allocation large enough to hold all of
263 * the currently-loaded objects. Keep this as a macro since it calls
264 * alloca and we want that to occur within the scope of the caller.
266 #define donelist_init(dlp) \
267 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
268 assert((dlp)->objs != NULL), \
269 (dlp)->num_alloc = obj_count, \
272 #define UTRACE_DLOPEN_START 1
273 #define UTRACE_DLOPEN_STOP 2
274 #define UTRACE_DLCLOSE_START 3
275 #define UTRACE_DLCLOSE_STOP 4
276 #define UTRACE_LOAD_OBJECT 5
277 #define UTRACE_UNLOAD_OBJECT 6
278 #define UTRACE_ADD_RUNDEP 7
279 #define UTRACE_PRELOAD_FINISHED 8
280 #define UTRACE_INIT_CALL 9
281 #define UTRACE_FINI_CALL 10
284 char sig[4]; /* 'RTLD' */
287 void *mapbase; /* Used for 'parent' and 'init/fini' */
289 int refcnt; /* Used for 'mode' */
290 char name[MAXPATHLEN];
293 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
294 if (ld_utrace != NULL) \
295 ld_utrace_log(e, h, mb, ms, r, n); \
299 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
300 int refcnt, const char *name)
302 struct utrace_rtld ut;
310 ut.mapbase = mapbase;
311 ut.mapsize = mapsize;
313 bzero(ut.name, sizeof(ut.name));
315 strlcpy(ut.name, name, sizeof(ut.name));
316 utrace(&ut, sizeof(ut));
320 * Main entry point for dynamic linking. The first argument is the
321 * stack pointer. The stack is expected to be laid out as described
322 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
323 * Specifically, the stack pointer points to a word containing
324 * ARGC. Following that in the stack is a null-terminated sequence
325 * of pointers to argument strings. Then comes a null-terminated
326 * sequence of pointers to environment strings. Finally, there is a
327 * sequence of "auxiliary vector" entries.
329 * The second argument points to a place to store the dynamic linker's
330 * exit procedure pointer and the third to a place to store the main
333 * The return value is the main program's entry point.
336 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
338 Elf_Auxinfo *aux_info[AT_COUNT];
346 Objlist_Entry *entry;
348 Obj_Entry **preload_tail;
349 Obj_Entry *last_interposer;
351 RtldLockState lockstate;
352 char *library_path_rpath;
357 * On entry, the dynamic linker itself has not been relocated yet.
358 * Be very careful not to reference any global data until after
359 * init_rtld has returned. It is OK to reference file-scope statics
360 * and string constants, and to call static and global functions.
363 /* Find the auxiliary vector on the stack. */
366 sp += argc + 1; /* Skip over arguments and NULL terminator */
368 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
370 aux = (Elf_Auxinfo *) sp;
372 /* Digest the auxiliary vector. */
373 for (i = 0; i < AT_COUNT; i++)
375 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
376 if (auxp->a_type < AT_COUNT)
377 aux_info[auxp->a_type] = auxp;
380 /* Initialize and relocate ourselves. */
381 assert(aux_info[AT_BASE] != NULL);
382 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
384 __progname = obj_rtld.path;
385 argv0 = argv[0] != NULL ? argv[0] : "(null)";
390 if (aux_info[AT_CANARY] != NULL &&
391 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
392 i = aux_info[AT_CANARYLEN]->a_un.a_val;
393 if (i > sizeof(__stack_chk_guard))
394 i = sizeof(__stack_chk_guard);
395 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
400 len = sizeof(__stack_chk_guard);
401 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
402 len != sizeof(__stack_chk_guard)) {
403 /* If sysctl was unsuccessful, use the "terminator canary". */
404 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
405 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
406 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
407 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
411 trust = !issetugid();
413 ld_bind_now = getenv(LD_ "BIND_NOW");
415 * If the process is tainted, then we un-set the dangerous environment
416 * variables. The process will be marked as tainted until setuid(2)
417 * is called. If any child process calls setuid(2) we do not want any
418 * future processes to honor the potentially un-safe variables.
421 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
422 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
423 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
424 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
425 _rtld_error("environment corrupt; aborting");
429 ld_debug = getenv(LD_ "DEBUG");
430 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
431 libmap_override = getenv(LD_ "LIBMAP");
432 ld_library_path = getenv(LD_ "LIBRARY_PATH");
433 ld_preload = getenv(LD_ "PRELOAD");
434 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
435 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
436 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
437 if (library_path_rpath != NULL) {
438 if (library_path_rpath[0] == 'y' ||
439 library_path_rpath[0] == 'Y' ||
440 library_path_rpath[0] == '1')
441 ld_library_path_rpath = true;
443 ld_library_path_rpath = false;
445 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
446 (ld_library_path != NULL) || (ld_preload != NULL) ||
447 (ld_elf_hints_path != NULL) || ld_loadfltr;
448 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
449 ld_utrace = getenv(LD_ "UTRACE");
451 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
452 ld_elf_hints_path = _PATH_ELF_HINTS;
454 if (ld_debug != NULL && *ld_debug != '\0')
456 dbg("%s is initialized, base address = %p", __progname,
457 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
458 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
459 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
461 dbg("initializing thread locks");
465 * Load the main program, or process its program header if it is
468 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
469 int fd = aux_info[AT_EXECFD]->a_un.a_val;
470 dbg("loading main program");
471 obj_main = map_object(fd, argv0, NULL);
473 if (obj_main == NULL)
475 max_stack_flags = obj->stack_flags;
476 } else { /* Main program already loaded. */
477 const Elf_Phdr *phdr;
481 dbg("processing main program's program header");
482 assert(aux_info[AT_PHDR] != NULL);
483 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
484 assert(aux_info[AT_PHNUM] != NULL);
485 phnum = aux_info[AT_PHNUM]->a_un.a_val;
486 assert(aux_info[AT_PHENT] != NULL);
487 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
488 assert(aux_info[AT_ENTRY] != NULL);
489 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
490 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
494 if (aux_info[AT_EXECPATH] != 0) {
496 char buf[MAXPATHLEN];
498 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
499 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
500 if (kexecpath[0] == '/')
501 obj_main->path = kexecpath;
502 else if (getcwd(buf, sizeof(buf)) == NULL ||
503 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
504 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
505 obj_main->path = xstrdup(argv0);
507 obj_main->path = xstrdup(buf);
509 dbg("No AT_EXECPATH");
510 obj_main->path = xstrdup(argv0);
512 dbg("obj_main path %s", obj_main->path);
513 obj_main->mainprog = true;
515 if (aux_info[AT_STACKPROT] != NULL &&
516 aux_info[AT_STACKPROT]->a_un.a_val != 0)
517 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
521 * Get the actual dynamic linker pathname from the executable if
522 * possible. (It should always be possible.) That ensures that
523 * gdb will find the right dynamic linker even if a non-standard
526 if (obj_main->interp != NULL &&
527 strcmp(obj_main->interp, obj_rtld.path) != 0) {
529 obj_rtld.path = xstrdup(obj_main->interp);
530 __progname = obj_rtld.path;
534 digest_dynamic(obj_main, 0);
535 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
536 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
537 obj_main->dynsymcount);
539 linkmap_add(obj_main);
540 linkmap_add(&obj_rtld);
542 /* Link the main program into the list of objects. */
543 *obj_tail = obj_main;
544 obj_tail = &obj_main->next;
548 /* Initialize a fake symbol for resolving undefined weak references. */
549 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
550 sym_zero.st_shndx = SHN_UNDEF;
551 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
554 libmap_disable = (bool)lm_init(libmap_override);
556 dbg("loading LD_PRELOAD libraries");
557 if (load_preload_objects() == -1)
559 preload_tail = obj_tail;
561 dbg("loading needed objects");
562 if (load_needed_objects(obj_main, 0) == -1)
565 /* Make a list of all objects loaded at startup. */
566 last_interposer = obj_main;
567 for (obj = obj_list; obj != NULL; obj = obj->next) {
568 if (obj->z_interpose && obj != obj_main) {
569 objlist_put_after(&list_main, last_interposer, obj);
570 last_interposer = obj;
572 objlist_push_tail(&list_main, obj);
577 dbg("checking for required versions");
578 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
581 if (ld_tracing) { /* We're done */
582 trace_loaded_objects(obj_main);
586 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
587 dump_relocations(obj_main);
592 * Processing tls relocations requires having the tls offsets
593 * initialized. Prepare offsets before starting initial
594 * relocation processing.
596 dbg("initializing initial thread local storage offsets");
597 STAILQ_FOREACH(entry, &list_main, link) {
599 * Allocate all the initial objects out of the static TLS
600 * block even if they didn't ask for it.
602 allocate_tls_offset(entry->obj);
605 if (relocate_objects(obj_main,
606 ld_bind_now != NULL && *ld_bind_now != '\0',
607 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
610 dbg("doing copy relocations");
611 if (do_copy_relocations(obj_main) == -1)
614 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
615 dump_relocations(obj_main);
620 * Setup TLS for main thread. This must be done after the
621 * relocations are processed, since tls initialization section
622 * might be the subject for relocations.
624 dbg("initializing initial thread local storage");
625 allocate_initial_tls(obj_list);
627 dbg("initializing key program variables");
628 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
629 set_program_var("environ", env);
630 set_program_var("__elf_aux_vector", aux);
632 /* Make a list of init functions to call. */
633 objlist_init(&initlist);
634 initlist_add_objects(obj_list, preload_tail, &initlist);
636 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
638 map_stacks_exec(NULL);
640 dbg("resolving ifuncs");
641 if (resolve_objects_ifunc(obj_main,
642 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
646 if (!obj_main->crt_no_init) {
648 * Make sure we don't call the main program's init and fini
649 * functions for binaries linked with old crt1 which calls
652 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
653 obj_main->preinit_array = obj_main->init_array =
654 obj_main->fini_array = (Elf_Addr)NULL;
657 wlock_acquire(rtld_bind_lock, &lockstate);
658 if (obj_main->crt_no_init)
660 objlist_call_init(&initlist, &lockstate);
661 _r_debug_postinit(&obj_main->linkmap);
662 objlist_clear(&initlist);
663 dbg("loading filtees");
664 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
665 if (ld_loadfltr || obj->z_loadfltr)
666 load_filtees(obj, 0, &lockstate);
668 lock_release(rtld_bind_lock, &lockstate);
670 dbg("transferring control to program entry point = %p", obj_main->entry);
672 /* Return the exit procedure and the program entry point. */
673 *exit_proc = rtld_exit;
675 return (func_ptr_type) obj_main->entry;
679 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
684 ptr = (void *)make_function_pointer(def, obj);
685 target = ((Elf_Addr (*)(void))ptr)();
686 return ((void *)target);
690 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
694 const Obj_Entry *defobj;
697 RtldLockState lockstate;
699 rlock_acquire(rtld_bind_lock, &lockstate);
700 if (sigsetjmp(lockstate.env, 0) != 0)
701 lock_upgrade(rtld_bind_lock, &lockstate);
703 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
705 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
707 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
708 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
712 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
713 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
715 target = (Elf_Addr)(defobj->relocbase + def->st_value);
717 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
718 defobj->strtab + def->st_name, basename(obj->path),
719 (void *)target, basename(defobj->path));
722 * Write the new contents for the jmpslot. Note that depending on
723 * architecture, the value which we need to return back to the
724 * lazy binding trampoline may or may not be the target
725 * address. The value returned from reloc_jmpslot() is the value
726 * that the trampoline needs.
728 target = reloc_jmpslot(where, target, defobj, obj, rel);
729 lock_release(rtld_bind_lock, &lockstate);
734 * Error reporting function. Use it like printf. If formats the message
735 * into a buffer, and sets things up so that the next call to dlerror()
736 * will return the message.
739 _rtld_error(const char *fmt, ...)
741 static char buf[512];
745 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
751 * Return a dynamically-allocated copy of the current error message, if any.
756 return error_message == NULL ? NULL : xstrdup(error_message);
760 * Restore the current error message from a copy which was previously saved
761 * by errmsg_save(). The copy is freed.
764 errmsg_restore(char *saved_msg)
766 if (saved_msg == NULL)
767 error_message = NULL;
769 _rtld_error("%s", saved_msg);
775 basename(const char *name)
777 const char *p = strrchr(name, '/');
778 return p != NULL ? p + 1 : name;
781 static struct utsname uts;
784 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
785 const char *subst, bool may_free)
787 char *p, *p1, *res, *resp;
788 int subst_len, kw_len, subst_count, old_len, new_len;
793 * First, count the number of the keyword occurences, to
794 * preallocate the final string.
796 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
803 * If the keyword is not found, just return.
805 * Return non-substituted string if resolution failed. We
806 * cannot do anything more reasonable, the failure mode of the
807 * caller is unresolved library anyway.
809 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
810 return (may_free ? real : xstrdup(real));
812 subst = obj->origin_path;
815 * There is indeed something to substitute. Calculate the
816 * length of the resulting string, and allocate it.
818 subst_len = strlen(subst);
819 old_len = strlen(real);
820 new_len = old_len + (subst_len - kw_len) * subst_count;
821 res = xmalloc(new_len + 1);
824 * Now, execute the substitution loop.
826 for (p = real, resp = res, *resp = '\0';;) {
829 /* Copy the prefix before keyword. */
830 memcpy(resp, p, p1 - p);
832 /* Keyword replacement. */
833 memcpy(resp, subst, subst_len);
841 /* Copy to the end of string and finish. */
849 origin_subst(Obj_Entry *obj, char *real)
851 char *res1, *res2, *res3, *res4;
853 if (obj == NULL || !trust)
854 return (xstrdup(real));
855 if (uts.sysname[0] == '\0') {
856 if (uname(&uts) != 0) {
857 _rtld_error("utsname failed: %d", errno);
861 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
862 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
863 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
864 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
871 const char *msg = dlerror();
875 rtld_fdputstr(STDERR_FILENO, msg);
876 rtld_fdputchar(STDERR_FILENO, '\n');
881 * Process a shared object's DYNAMIC section, and save the important
882 * information in its Obj_Entry structure.
885 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
886 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
889 Needed_Entry **needed_tail = &obj->needed;
890 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
891 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
892 const Elf_Hashelt *hashtab;
893 const Elf32_Word *hashval;
894 Elf32_Word bkt, nmaskwords;
896 int plttype = DT_REL;
902 obj->bind_now = false;
903 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
904 switch (dynp->d_tag) {
907 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
911 obj->relsize = dynp->d_un.d_val;
915 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
919 obj->pltrel = (const Elf_Rel *)
920 (obj->relocbase + dynp->d_un.d_ptr);
924 obj->pltrelsize = dynp->d_un.d_val;
928 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
932 obj->relasize = dynp->d_un.d_val;
936 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
940 plttype = dynp->d_un.d_val;
941 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
945 obj->symtab = (const Elf_Sym *)
946 (obj->relocbase + dynp->d_un.d_ptr);
950 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
954 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
958 obj->strsize = dynp->d_un.d_val;
962 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
967 obj->verneednum = dynp->d_un.d_val;
971 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
976 obj->verdefnum = dynp->d_un.d_val;
980 obj->versyms = (const Elf_Versym *)(obj->relocbase +
986 hashtab = (const Elf_Hashelt *)(obj->relocbase +
988 obj->nbuckets = hashtab[0];
989 obj->nchains = hashtab[1];
990 obj->buckets = hashtab + 2;
991 obj->chains = obj->buckets + obj->nbuckets;
992 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
993 obj->buckets != NULL;
999 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1001 obj->nbuckets_gnu = hashtab[0];
1002 obj->symndx_gnu = hashtab[1];
1003 nmaskwords = hashtab[2];
1004 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1005 obj->maskwords_bm_gnu = nmaskwords - 1;
1006 obj->shift2_gnu = hashtab[3];
1007 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1008 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1009 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1011 /* Number of bitmask words is required to be power of 2 */
1012 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1013 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1019 Needed_Entry *nep = NEW(Needed_Entry);
1020 nep->name = dynp->d_un.d_val;
1025 needed_tail = &nep->next;
1031 Needed_Entry *nep = NEW(Needed_Entry);
1032 nep->name = dynp->d_un.d_val;
1036 *needed_filtees_tail = nep;
1037 needed_filtees_tail = &nep->next;
1043 Needed_Entry *nep = NEW(Needed_Entry);
1044 nep->name = dynp->d_un.d_val;
1048 *needed_aux_filtees_tail = nep;
1049 needed_aux_filtees_tail = &nep->next;
1054 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1058 obj->textrel = true;
1062 obj->symbolic = true;
1067 * We have to wait until later to process this, because we
1068 * might not have gotten the address of the string table yet.
1078 *dyn_runpath = dynp;
1082 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1085 case DT_PREINIT_ARRAY:
1086 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1089 case DT_PREINIT_ARRAYSZ:
1090 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1094 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1097 case DT_INIT_ARRAYSZ:
1098 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1102 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1106 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1109 case DT_FINI_ARRAYSZ:
1110 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1114 * Don't process DT_DEBUG on MIPS as the dynamic section
1115 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1120 /* XXX - not implemented yet */
1122 dbg("Filling in DT_DEBUG entry");
1123 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1128 if (dynp->d_un.d_val & DF_ORIGIN)
1129 obj->z_origin = true;
1130 if (dynp->d_un.d_val & DF_SYMBOLIC)
1131 obj->symbolic = true;
1132 if (dynp->d_un.d_val & DF_TEXTREL)
1133 obj->textrel = true;
1134 if (dynp->d_un.d_val & DF_BIND_NOW)
1135 obj->bind_now = true;
1136 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1140 case DT_MIPS_LOCAL_GOTNO:
1141 obj->local_gotno = dynp->d_un.d_val;
1144 case DT_MIPS_SYMTABNO:
1145 obj->symtabno = dynp->d_un.d_val;
1148 case DT_MIPS_GOTSYM:
1149 obj->gotsym = dynp->d_un.d_val;
1152 case DT_MIPS_RLD_MAP:
1153 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1158 if (dynp->d_un.d_val & DF_1_NOOPEN)
1159 obj->z_noopen = true;
1160 if (dynp->d_un.d_val & DF_1_ORIGIN)
1161 obj->z_origin = true;
1162 if (dynp->d_un.d_val & DF_1_GLOBAL)
1163 obj->z_global = true;
1164 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1165 obj->bind_now = true;
1166 if (dynp->d_un.d_val & DF_1_NODELETE)
1167 obj->z_nodelete = true;
1168 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1169 obj->z_loadfltr = true;
1170 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1171 obj->z_interpose = true;
1172 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1173 obj->z_nodeflib = true;
1178 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1185 obj->traced = false;
1187 if (plttype == DT_RELA) {
1188 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1190 obj->pltrelasize = obj->pltrelsize;
1191 obj->pltrelsize = 0;
1194 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1195 if (obj->valid_hash_sysv)
1196 obj->dynsymcount = obj->nchains;
1197 else if (obj->valid_hash_gnu) {
1198 obj->dynsymcount = 0;
1199 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1200 if (obj->buckets_gnu[bkt] == 0)
1202 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1205 while ((*hashval++ & 1u) == 0);
1207 obj->dynsymcount += obj->symndx_gnu;
1212 obj_resolve_origin(Obj_Entry *obj)
1215 if (obj->origin_path != NULL)
1217 obj->origin_path = xmalloc(PATH_MAX);
1218 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1222 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1223 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1226 if (obj->z_origin && !obj_resolve_origin(obj))
1229 if (dyn_runpath != NULL) {
1230 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1231 obj->runpath = origin_subst(obj, obj->runpath);
1232 } else if (dyn_rpath != NULL) {
1233 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1234 obj->rpath = origin_subst(obj, obj->rpath);
1236 if (dyn_soname != NULL)
1237 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1241 digest_dynamic(Obj_Entry *obj, int early)
1243 const Elf_Dyn *dyn_rpath;
1244 const Elf_Dyn *dyn_soname;
1245 const Elf_Dyn *dyn_runpath;
1247 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1248 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1252 * Process a shared object's program header. This is used only for the
1253 * main program, when the kernel has already loaded the main program
1254 * into memory before calling the dynamic linker. It creates and
1255 * returns an Obj_Entry structure.
1258 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1261 const Elf_Phdr *phlimit = phdr + phnum;
1263 Elf_Addr note_start, note_end;
1267 for (ph = phdr; ph < phlimit; ph++) {
1268 if (ph->p_type != PT_PHDR)
1272 obj->phsize = ph->p_memsz;
1273 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1277 obj->stack_flags = PF_X | PF_R | PF_W;
1279 for (ph = phdr; ph < phlimit; ph++) {
1280 switch (ph->p_type) {
1283 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1287 if (nsegs == 0) { /* First load segment */
1288 obj->vaddrbase = trunc_page(ph->p_vaddr);
1289 obj->mapbase = obj->vaddrbase + obj->relocbase;
1290 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1292 } else { /* Last load segment */
1293 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1300 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1305 obj->tlssize = ph->p_memsz;
1306 obj->tlsalign = ph->p_align;
1307 obj->tlsinitsize = ph->p_filesz;
1308 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1312 obj->stack_flags = ph->p_flags;
1316 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1317 obj->relro_size = round_page(ph->p_memsz);
1321 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1322 note_end = note_start + ph->p_filesz;
1323 digest_notes(obj, note_start, note_end);
1328 _rtld_error("%s: too few PT_LOAD segments", path);
1337 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1339 const Elf_Note *note;
1340 const char *note_name;
1343 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1344 note = (const Elf_Note *)((const char *)(note + 1) +
1345 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1346 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1347 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1348 note->n_descsz != sizeof(int32_t))
1350 if (note->n_type != ABI_NOTETYPE &&
1351 note->n_type != CRT_NOINIT_NOTETYPE)
1353 note_name = (const char *)(note + 1);
1354 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1355 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1357 switch (note->n_type) {
1359 /* FreeBSD osrel note */
1360 p = (uintptr_t)(note + 1);
1361 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1362 obj->osrel = *(const int32_t *)(p);
1363 dbg("note osrel %d", obj->osrel);
1365 case CRT_NOINIT_NOTETYPE:
1366 /* FreeBSD 'crt does not call init' note */
1367 obj->crt_no_init = true;
1368 dbg("note crt_no_init");
1375 dlcheck(void *handle)
1379 for (obj = obj_list; obj != NULL; obj = obj->next)
1380 if (obj == (Obj_Entry *) handle)
1383 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1384 _rtld_error("Invalid shared object handle %p", handle);
1391 * If the given object is already in the donelist, return true. Otherwise
1392 * add the object to the list and return false.
1395 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1399 for (i = 0; i < dlp->num_used; i++)
1400 if (dlp->objs[i] == obj)
1403 * Our donelist allocation should always be sufficient. But if
1404 * our threads locking isn't working properly, more shared objects
1405 * could have been loaded since we allocated the list. That should
1406 * never happen, but we'll handle it properly just in case it does.
1408 if (dlp->num_used < dlp->num_alloc)
1409 dlp->objs[dlp->num_used++] = obj;
1414 * Hash function for symbol table lookup. Don't even think about changing
1415 * this. It is specified by the System V ABI.
1418 elf_hash(const char *name)
1420 const unsigned char *p = (const unsigned char *) name;
1421 unsigned long h = 0;
1424 while (*p != '\0') {
1425 h = (h << 4) + *p++;
1426 if ((g = h & 0xf0000000) != 0)
1434 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1435 * unsigned in case it's implemented with a wider type.
1438 gnu_hash(const char *s)
1444 for (c = *s; c != '\0'; c = *++s)
1446 return (h & 0xffffffff);
1450 * Find the library with the given name, and return its full pathname.
1451 * The returned string is dynamically allocated. Generates an error
1452 * message and returns NULL if the library cannot be found.
1454 * If the second argument is non-NULL, then it refers to an already-
1455 * loaded shared object, whose library search path will be searched.
1457 * The search order is:
1458 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1459 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1461 * DT_RUNPATH in the referencing file
1462 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1464 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1466 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1469 find_library(const char *xname, const Obj_Entry *refobj)
1473 bool nodeflib, objgiven;
1475 objgiven = refobj != NULL;
1476 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1477 if (xname[0] != '/' && !trust) {
1478 _rtld_error("Absolute pathname required for shared object \"%s\"",
1482 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1483 __DECONST(char *, xname)));
1486 if (libmap_disable || !objgiven ||
1487 (name = lm_find(refobj->path, xname)) == NULL)
1488 name = (char *)xname;
1490 dbg(" Searching for \"%s\"", name);
1493 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1494 * back to pre-conforming behaviour if user requested so with
1495 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1498 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1499 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1501 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1502 (pathname = search_library_path(name, gethints(false))) != NULL ||
1503 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1506 nodeflib = objgiven ? refobj->z_nodeflib : false;
1508 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1509 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1510 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1511 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1513 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1514 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1515 (objgiven && !nodeflib &&
1516 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1520 if (objgiven && refobj->path != NULL) {
1521 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1522 name, basename(refobj->path));
1524 _rtld_error("Shared object \"%s\" not found", name);
1530 * Given a symbol number in a referencing object, find the corresponding
1531 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1532 * no definition was found. Returns a pointer to the Obj_Entry of the
1533 * defining object via the reference parameter DEFOBJ_OUT.
1536 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1537 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1538 RtldLockState *lockstate)
1542 const Obj_Entry *defobj;
1548 * If we have already found this symbol, get the information from
1551 if (symnum >= refobj->dynsymcount)
1552 return NULL; /* Bad object */
1553 if (cache != NULL && cache[symnum].sym != NULL) {
1554 *defobj_out = cache[symnum].obj;
1555 return cache[symnum].sym;
1558 ref = refobj->symtab + symnum;
1559 name = refobj->strtab + ref->st_name;
1564 * We don't have to do a full scale lookup if the symbol is local.
1565 * We know it will bind to the instance in this load module; to
1566 * which we already have a pointer (ie ref). By not doing a lookup,
1567 * we not only improve performance, but it also avoids unresolvable
1568 * symbols when local symbols are not in the hash table. This has
1569 * been seen with the ia64 toolchain.
1571 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1572 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1573 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1576 symlook_init(&req, name);
1578 req.ventry = fetch_ventry(refobj, symnum);
1579 req.lockstate = lockstate;
1580 res = symlook_default(&req, refobj);
1583 defobj = req.defobj_out;
1591 * If we found no definition and the reference is weak, treat the
1592 * symbol as having the value zero.
1594 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1600 *defobj_out = defobj;
1601 /* Record the information in the cache to avoid subsequent lookups. */
1602 if (cache != NULL) {
1603 cache[symnum].sym = def;
1604 cache[symnum].obj = defobj;
1607 if (refobj != &obj_rtld)
1608 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1614 * Return the search path from the ldconfig hints file, reading it if
1615 * necessary. If nostdlib is true, then the default search paths are
1616 * not added to result.
1618 * Returns NULL if there are problems with the hints file,
1619 * or if the search path there is empty.
1622 gethints(bool nostdlib)
1624 static char *hints, *filtered_path;
1625 struct elfhints_hdr hdr;
1626 struct fill_search_info_args sargs, hargs;
1627 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1628 struct dl_serpath *SLPpath, *hintpath;
1630 unsigned int SLPndx, hintndx, fndx, fcount;
1635 /* First call, read the hints file */
1636 if (hints == NULL) {
1637 /* Keep from trying again in case the hints file is bad. */
1640 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1642 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1643 hdr.magic != ELFHINTS_MAGIC ||
1648 p = xmalloc(hdr.dirlistlen + 1);
1649 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1650 read(fd, p, hdr.dirlistlen + 1) !=
1651 (ssize_t)hdr.dirlistlen + 1) {
1661 * If caller agreed to receive list which includes the default
1662 * paths, we are done. Otherwise, if we still did not
1663 * calculated filtered result, do it now.
1666 return (hints[0] != '\0' ? hints : NULL);
1667 if (filtered_path != NULL)
1671 * Obtain the list of all configured search paths, and the
1672 * list of the default paths.
1674 * First estimate the size of the results.
1676 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1678 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1681 sargs.request = RTLD_DI_SERINFOSIZE;
1682 sargs.serinfo = &smeta;
1683 hargs.request = RTLD_DI_SERINFOSIZE;
1684 hargs.serinfo = &hmeta;
1686 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1687 path_enumerate(p, fill_search_info, &hargs);
1689 SLPinfo = xmalloc(smeta.dls_size);
1690 hintinfo = xmalloc(hmeta.dls_size);
1693 * Next fetch both sets of paths.
1695 sargs.request = RTLD_DI_SERINFO;
1696 sargs.serinfo = SLPinfo;
1697 sargs.serpath = &SLPinfo->dls_serpath[0];
1698 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1700 hargs.request = RTLD_DI_SERINFO;
1701 hargs.serinfo = hintinfo;
1702 hargs.serpath = &hintinfo->dls_serpath[0];
1703 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1705 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1706 path_enumerate(p, fill_search_info, &hargs);
1709 * Now calculate the difference between two sets, by excluding
1710 * standard paths from the full set.
1714 filtered_path = xmalloc(hdr.dirlistlen + 1);
1715 hintpath = &hintinfo->dls_serpath[0];
1716 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1718 SLPpath = &SLPinfo->dls_serpath[0];
1720 * Check each standard path against current.
1722 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1723 /* matched, skip the path */
1724 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1732 * Not matched against any standard path, add the path
1733 * to result. Separate consequtive paths with ':'.
1736 filtered_path[fndx] = ':';
1740 flen = strlen(hintpath->dls_name);
1741 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1744 filtered_path[fndx] = '\0';
1750 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1754 init_dag(Obj_Entry *root)
1756 const Needed_Entry *needed;
1757 const Objlist_Entry *elm;
1760 if (root->dag_inited)
1762 donelist_init(&donelist);
1764 /* Root object belongs to own DAG. */
1765 objlist_push_tail(&root->dldags, root);
1766 objlist_push_tail(&root->dagmembers, root);
1767 donelist_check(&donelist, root);
1770 * Add dependencies of root object to DAG in breadth order
1771 * by exploiting the fact that each new object get added
1772 * to the tail of the dagmembers list.
1774 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1775 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1776 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1778 objlist_push_tail(&needed->obj->dldags, root);
1779 objlist_push_tail(&root->dagmembers, needed->obj);
1782 root->dag_inited = true;
1786 process_z(Obj_Entry *root)
1788 const Objlist_Entry *elm;
1792 * Walk over object DAG and process every dependent object
1793 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
1794 * to grow their own DAG.
1796 * For DF_1_GLOBAL, DAG is required for symbol lookups in
1797 * symlook_global() to work.
1799 * For DF_1_NODELETE, the DAG should have its reference upped.
1801 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1805 if (obj->z_nodelete && !obj->ref_nodel) {
1806 dbg("obj %s -z nodelete", obj->path);
1809 obj->ref_nodel = true;
1811 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
1812 dbg("obj %s -z global", obj->path);
1813 objlist_push_tail(&list_global, obj);
1819 * Initialize the dynamic linker. The argument is the address at which
1820 * the dynamic linker has been mapped into memory. The primary task of
1821 * this function is to relocate the dynamic linker.
1824 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1826 Obj_Entry objtmp; /* Temporary rtld object */
1827 const Elf_Dyn *dyn_rpath;
1828 const Elf_Dyn *dyn_soname;
1829 const Elf_Dyn *dyn_runpath;
1831 #ifdef RTLD_INIT_PAGESIZES_EARLY
1832 /* The page size is required by the dynamic memory allocator. */
1833 init_pagesizes(aux_info);
1837 * Conjure up an Obj_Entry structure for the dynamic linker.
1839 * The "path" member can't be initialized yet because string constants
1840 * cannot yet be accessed. Below we will set it correctly.
1842 memset(&objtmp, 0, sizeof(objtmp));
1845 objtmp.mapbase = mapbase;
1847 objtmp.relocbase = mapbase;
1849 if (RTLD_IS_DYNAMIC()) {
1850 objtmp.dynamic = rtld_dynamic(&objtmp);
1851 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1852 assert(objtmp.needed == NULL);
1853 #if !defined(__mips__)
1854 /* MIPS has a bogus DT_TEXTREL. */
1855 assert(!objtmp.textrel);
1859 * Temporarily put the dynamic linker entry into the object list, so
1860 * that symbols can be found.
1863 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1866 /* Initialize the object list. */
1867 obj_tail = &obj_list;
1869 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1870 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1872 #ifndef RTLD_INIT_PAGESIZES_EARLY
1873 /* The page size is required by the dynamic memory allocator. */
1874 init_pagesizes(aux_info);
1877 if (aux_info[AT_OSRELDATE] != NULL)
1878 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1880 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1882 /* Replace the path with a dynamically allocated copy. */
1883 obj_rtld.path = xstrdup(PATH_RTLD);
1885 r_debug.r_brk = r_debug_state;
1886 r_debug.r_state = RT_CONSISTENT;
1890 * Retrieve the array of supported page sizes. The kernel provides the page
1891 * sizes in increasing order.
1894 init_pagesizes(Elf_Auxinfo **aux_info)
1896 static size_t psa[MAXPAGESIZES];
1900 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1902 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1903 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1906 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1909 /* As a fallback, retrieve the base page size. */
1910 size = sizeof(psa[0]);
1911 if (aux_info[AT_PAGESZ] != NULL) {
1912 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1916 mib[1] = HW_PAGESIZE;
1920 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1921 _rtld_error("sysctl for hw.pagesize(s) failed");
1927 npagesizes = size / sizeof(pagesizes[0]);
1928 /* Discard any invalid entries at the end of the array. */
1929 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1934 * Add the init functions from a needed object list (and its recursive
1935 * needed objects) to "list". This is not used directly; it is a helper
1936 * function for initlist_add_objects(). The write lock must be held
1937 * when this function is called.
1940 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1942 /* Recursively process the successor needed objects. */
1943 if (needed->next != NULL)
1944 initlist_add_neededs(needed->next, list);
1946 /* Process the current needed object. */
1947 if (needed->obj != NULL)
1948 initlist_add_objects(needed->obj, &needed->obj->next, list);
1952 * Scan all of the DAGs rooted in the range of objects from "obj" to
1953 * "tail" and add their init functions to "list". This recurses over
1954 * the DAGs and ensure the proper init ordering such that each object's
1955 * needed libraries are initialized before the object itself. At the
1956 * same time, this function adds the objects to the global finalization
1957 * list "list_fini" in the opposite order. The write lock must be
1958 * held when this function is called.
1961 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1964 if (obj->init_scanned || obj->init_done)
1966 obj->init_scanned = true;
1968 /* Recursively process the successor objects. */
1969 if (&obj->next != tail)
1970 initlist_add_objects(obj->next, tail, list);
1972 /* Recursively process the needed objects. */
1973 if (obj->needed != NULL)
1974 initlist_add_neededs(obj->needed, list);
1975 if (obj->needed_filtees != NULL)
1976 initlist_add_neededs(obj->needed_filtees, list);
1977 if (obj->needed_aux_filtees != NULL)
1978 initlist_add_neededs(obj->needed_aux_filtees, list);
1980 /* Add the object to the init list. */
1981 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1982 obj->init_array != (Elf_Addr)NULL)
1983 objlist_push_tail(list, obj);
1985 /* Add the object to the global fini list in the reverse order. */
1986 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1987 && !obj->on_fini_list) {
1988 objlist_push_head(&list_fini, obj);
1989 obj->on_fini_list = true;
1994 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1998 free_needed_filtees(Needed_Entry *n)
2000 Needed_Entry *needed, *needed1;
2002 for (needed = n; needed != NULL; needed = needed->next) {
2003 if (needed->obj != NULL) {
2004 dlclose(needed->obj);
2008 for (needed = n; needed != NULL; needed = needed1) {
2009 needed1 = needed->next;
2015 unload_filtees(Obj_Entry *obj)
2018 free_needed_filtees(obj->needed_filtees);
2019 obj->needed_filtees = NULL;
2020 free_needed_filtees(obj->needed_aux_filtees);
2021 obj->needed_aux_filtees = NULL;
2022 obj->filtees_loaded = false;
2026 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2027 RtldLockState *lockstate)
2030 for (; needed != NULL; needed = needed->next) {
2031 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2032 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2033 RTLD_LOCAL, lockstate);
2038 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2041 lock_restart_for_upgrade(lockstate);
2042 if (!obj->filtees_loaded) {
2043 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2044 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2045 obj->filtees_loaded = true;
2050 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2054 for (; needed != NULL; needed = needed->next) {
2055 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2056 flags & ~RTLD_LO_NOLOAD);
2057 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2064 * Given a shared object, traverse its list of needed objects, and load
2065 * each of them. Returns 0 on success. Generates an error message and
2066 * returns -1 on failure.
2069 load_needed_objects(Obj_Entry *first, int flags)
2073 for (obj = first; obj != NULL; obj = obj->next) {
2074 if (process_needed(obj, obj->needed, flags) == -1)
2081 load_preload_objects(void)
2083 char *p = ld_preload;
2085 static const char delim[] = " \t:;";
2090 p += strspn(p, delim);
2091 while (*p != '\0') {
2092 size_t len = strcspn(p, delim);
2097 obj = load_object(p, -1, NULL, 0);
2099 return -1; /* XXX - cleanup */
2100 obj->z_interpose = true;
2103 p += strspn(p, delim);
2105 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2110 printable_path(const char *path)
2113 return (path == NULL ? "<unknown>" : path);
2117 * Load a shared object into memory, if it is not already loaded. The
2118 * object may be specified by name or by user-supplied file descriptor
2119 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2122 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2126 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2134 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2135 if (object_match_name(obj, name))
2139 path = find_library(name, refobj);
2146 * If we didn't find a match by pathname, or the name is not
2147 * supplied, open the file and check again by device and inode.
2148 * This avoids false mismatches caused by multiple links or ".."
2151 * To avoid a race, we open the file and use fstat() rather than
2156 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2157 _rtld_error("Cannot open \"%s\"", path);
2162 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2164 _rtld_error("Cannot dup fd");
2169 if (fstat(fd, &sb) == -1) {
2170 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2175 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2176 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2178 if (obj != NULL && name != NULL) {
2179 object_add_name(obj, name);
2184 if (flags & RTLD_LO_NOLOAD) {
2190 /* First use of this object, so we must map it in */
2191 obj = do_load_object(fd, name, path, &sb, flags);
2200 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2207 * but first, make sure that environment variables haven't been
2208 * used to circumvent the noexec flag on a filesystem.
2210 if (dangerous_ld_env) {
2211 if (fstatfs(fd, &fs) != 0) {
2212 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2215 if (fs.f_flags & MNT_NOEXEC) {
2216 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2220 dbg("loading \"%s\"", printable_path(path));
2221 obj = map_object(fd, printable_path(path), sbp);
2226 * If DT_SONAME is present in the object, digest_dynamic2 already
2227 * added it to the object names.
2230 object_add_name(obj, name);
2232 digest_dynamic(obj, 0);
2233 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2234 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2235 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2237 dbg("refusing to load non-loadable \"%s\"", obj->path);
2238 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2239 munmap(obj->mapbase, obj->mapsize);
2244 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2246 obj_tail = &obj->next;
2249 linkmap_add(obj); /* for GDB & dlinfo() */
2250 max_stack_flags |= obj->stack_flags;
2252 dbg(" %p .. %p: %s", obj->mapbase,
2253 obj->mapbase + obj->mapsize - 1, obj->path);
2255 dbg(" WARNING: %s has impure text", obj->path);
2256 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2263 obj_from_addr(const void *addr)
2267 for (obj = obj_list; obj != NULL; obj = obj->next) {
2268 if (addr < (void *) obj->mapbase)
2270 if (addr < (void *) (obj->mapbase + obj->mapsize))
2279 Elf_Addr *preinit_addr;
2282 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2283 if (preinit_addr == NULL)
2286 for (index = 0; index < obj_main->preinit_array_num; index++) {
2287 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2288 dbg("calling preinit function for %s at %p", obj_main->path,
2289 (void *)preinit_addr[index]);
2290 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2291 0, 0, obj_main->path);
2292 call_init_pointer(obj_main, preinit_addr[index]);
2298 * Call the finalization functions for each of the objects in "list"
2299 * belonging to the DAG of "root" and referenced once. If NULL "root"
2300 * is specified, every finalization function will be called regardless
2301 * of the reference count and the list elements won't be freed. All of
2302 * the objects are expected to have non-NULL fini functions.
2305 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2309 Elf_Addr *fini_addr;
2312 assert(root == NULL || root->refcount == 1);
2315 * Preserve the current error message since a fini function might
2316 * call into the dynamic linker and overwrite it.
2318 saved_msg = errmsg_save();
2320 STAILQ_FOREACH(elm, list, link) {
2321 if (root != NULL && (elm->obj->refcount != 1 ||
2322 objlist_find(&root->dagmembers, elm->obj) == NULL))
2324 /* Remove object from fini list to prevent recursive invocation. */
2325 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2327 * XXX: If a dlopen() call references an object while the
2328 * fini function is in progress, we might end up trying to
2329 * unload the referenced object in dlclose() or the object
2330 * won't be unloaded although its fini function has been
2333 lock_release(rtld_bind_lock, lockstate);
2336 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2337 * When this happens, DT_FINI_ARRAY is processed first.
2339 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2340 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2341 for (index = elm->obj->fini_array_num - 1; index >= 0;
2343 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2344 dbg("calling fini function for %s at %p",
2345 elm->obj->path, (void *)fini_addr[index]);
2346 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2347 (void *)fini_addr[index], 0, 0, elm->obj->path);
2348 call_initfini_pointer(elm->obj, fini_addr[index]);
2352 if (elm->obj->fini != (Elf_Addr)NULL) {
2353 dbg("calling fini function for %s at %p", elm->obj->path,
2354 (void *)elm->obj->fini);
2355 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2356 0, 0, elm->obj->path);
2357 call_initfini_pointer(elm->obj, elm->obj->fini);
2359 wlock_acquire(rtld_bind_lock, lockstate);
2360 /* No need to free anything if process is going down. */
2364 * We must restart the list traversal after every fini call
2365 * because a dlclose() call from the fini function or from
2366 * another thread might have modified the reference counts.
2370 } while (elm != NULL);
2371 errmsg_restore(saved_msg);
2375 * Call the initialization functions for each of the objects in
2376 * "list". All of the objects are expected to have non-NULL init
2380 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2385 Elf_Addr *init_addr;
2389 * Clean init_scanned flag so that objects can be rechecked and
2390 * possibly initialized earlier if any of vectors called below
2391 * cause the change by using dlopen.
2393 for (obj = obj_list; obj != NULL; obj = obj->next)
2394 obj->init_scanned = false;
2397 * Preserve the current error message since an init function might
2398 * call into the dynamic linker and overwrite it.
2400 saved_msg = errmsg_save();
2401 STAILQ_FOREACH(elm, list, link) {
2402 if (elm->obj->init_done) /* Initialized early. */
2405 * Race: other thread might try to use this object before current
2406 * one completes the initilization. Not much can be done here
2407 * without better locking.
2409 elm->obj->init_done = true;
2410 lock_release(rtld_bind_lock, lockstate);
2413 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2414 * When this happens, DT_INIT is processed first.
2416 if (elm->obj->init != (Elf_Addr)NULL) {
2417 dbg("calling init function for %s at %p", elm->obj->path,
2418 (void *)elm->obj->init);
2419 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2420 0, 0, elm->obj->path);
2421 call_initfini_pointer(elm->obj, elm->obj->init);
2423 init_addr = (Elf_Addr *)elm->obj->init_array;
2424 if (init_addr != NULL) {
2425 for (index = 0; index < elm->obj->init_array_num; index++) {
2426 if (init_addr[index] != 0 && init_addr[index] != 1) {
2427 dbg("calling init function for %s at %p", elm->obj->path,
2428 (void *)init_addr[index]);
2429 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2430 (void *)init_addr[index], 0, 0, elm->obj->path);
2431 call_init_pointer(elm->obj, init_addr[index]);
2435 wlock_acquire(rtld_bind_lock, lockstate);
2437 errmsg_restore(saved_msg);
2441 objlist_clear(Objlist *list)
2445 while (!STAILQ_EMPTY(list)) {
2446 elm = STAILQ_FIRST(list);
2447 STAILQ_REMOVE_HEAD(list, link);
2452 static Objlist_Entry *
2453 objlist_find(Objlist *list, const Obj_Entry *obj)
2457 STAILQ_FOREACH(elm, list, link)
2458 if (elm->obj == obj)
2464 objlist_init(Objlist *list)
2470 objlist_push_head(Objlist *list, Obj_Entry *obj)
2474 elm = NEW(Objlist_Entry);
2476 STAILQ_INSERT_HEAD(list, elm, link);
2480 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2484 elm = NEW(Objlist_Entry);
2486 STAILQ_INSERT_TAIL(list, elm, link);
2490 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2492 Objlist_Entry *elm, *listelm;
2494 STAILQ_FOREACH(listelm, list, link) {
2495 if (listelm->obj == listobj)
2498 elm = NEW(Objlist_Entry);
2500 if (listelm != NULL)
2501 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2503 STAILQ_INSERT_TAIL(list, elm, link);
2507 objlist_remove(Objlist *list, Obj_Entry *obj)
2511 if ((elm = objlist_find(list, obj)) != NULL) {
2512 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2518 * Relocate dag rooted in the specified object.
2519 * Returns 0 on success, or -1 on failure.
2523 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2524 int flags, RtldLockState *lockstate)
2530 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2531 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2540 * Relocate single object.
2541 * Returns 0 on success, or -1 on failure.
2544 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2545 int flags, RtldLockState *lockstate)
2550 obj->relocated = true;
2552 dbg("relocating \"%s\"", obj->path);
2554 if (obj->symtab == NULL || obj->strtab == NULL ||
2555 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2556 _rtld_error("%s: Shared object has no run-time symbol table",
2562 /* There are relocations to the write-protected text segment. */
2563 if (mprotect(obj->mapbase, obj->textsize,
2564 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2565 _rtld_error("%s: Cannot write-enable text segment: %s",
2566 obj->path, rtld_strerror(errno));
2571 /* Process the non-PLT non-IFUNC relocations. */
2572 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2575 if (obj->textrel) { /* Re-protected the text segment. */
2576 if (mprotect(obj->mapbase, obj->textsize,
2577 PROT_READ|PROT_EXEC) == -1) {
2578 _rtld_error("%s: Cannot write-protect text segment: %s",
2579 obj->path, rtld_strerror(errno));
2584 /* Set the special PLT or GOT entries. */
2587 /* Process the PLT relocations. */
2588 if (reloc_plt(obj) == -1)
2590 /* Relocate the jump slots if we are doing immediate binding. */
2591 if (obj->bind_now || bind_now)
2592 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2596 * Process the non-PLT IFUNC relocations. The relocations are
2597 * processed in two phases, because IFUNC resolvers may
2598 * reference other symbols, which must be readily processed
2599 * before resolvers are called.
2601 if (obj->non_plt_gnu_ifunc &&
2602 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2605 if (obj->relro_size > 0) {
2606 if (mprotect(obj->relro_page, obj->relro_size,
2608 _rtld_error("%s: Cannot enforce relro protection: %s",
2609 obj->path, rtld_strerror(errno));
2615 * Set up the magic number and version in the Obj_Entry. These
2616 * were checked in the crt1.o from the original ElfKit, so we
2617 * set them for backward compatibility.
2619 obj->magic = RTLD_MAGIC;
2620 obj->version = RTLD_VERSION;
2626 * Relocate newly-loaded shared objects. The argument is a pointer to
2627 * the Obj_Entry for the first such object. All objects from the first
2628 * to the end of the list of objects are relocated. Returns 0 on success,
2632 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2633 int flags, RtldLockState *lockstate)
2638 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2639 error = relocate_object(obj, bind_now, rtldobj, flags,
2648 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2649 * referencing STT_GNU_IFUNC symbols is postponed till the other
2650 * relocations are done. The indirect functions specified as
2651 * ifunc are allowed to call other symbols, so we need to have
2652 * objects relocated before asking for resolution from indirects.
2654 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2655 * instead of the usual lazy handling of PLT slots. It is
2656 * consistent with how GNU does it.
2659 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2660 RtldLockState *lockstate)
2662 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2664 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2665 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2671 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2672 RtldLockState *lockstate)
2676 for (obj = first; obj != NULL; obj = obj->next) {
2677 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2684 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2685 RtldLockState *lockstate)
2689 STAILQ_FOREACH(elm, list, link) {
2690 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2698 * Cleanup procedure. It will be called (by the atexit mechanism) just
2699 * before the process exits.
2704 RtldLockState lockstate;
2706 wlock_acquire(rtld_bind_lock, &lockstate);
2708 objlist_call_fini(&list_fini, NULL, &lockstate);
2709 /* No need to remove the items from the list, since we are exiting. */
2710 if (!libmap_disable)
2712 lock_release(rtld_bind_lock, &lockstate);
2716 * Iterate over a search path, translate each element, and invoke the
2717 * callback on the result.
2720 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2726 path += strspn(path, ":;");
2727 while (*path != '\0') {
2731 len = strcspn(path, ":;");
2732 trans = lm_findn(NULL, path, len);
2734 res = callback(trans, strlen(trans), arg);
2736 res = callback(path, len, arg);
2742 path += strspn(path, ":;");
2748 struct try_library_args {
2756 try_library_path(const char *dir, size_t dirlen, void *param)
2758 struct try_library_args *arg;
2761 if (*dir == '/' || trust) {
2764 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2767 pathname = arg->buffer;
2768 strncpy(pathname, dir, dirlen);
2769 pathname[dirlen] = '/';
2770 strcpy(pathname + dirlen + 1, arg->name);
2772 dbg(" Trying \"%s\"", pathname);
2773 if (access(pathname, F_OK) == 0) { /* We found it */
2774 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2775 strcpy(pathname, arg->buffer);
2783 search_library_path(const char *name, const char *path)
2786 struct try_library_args arg;
2792 arg.namelen = strlen(name);
2793 arg.buffer = xmalloc(PATH_MAX);
2794 arg.buflen = PATH_MAX;
2796 p = path_enumerate(path, try_library_path, &arg);
2804 dlclose(void *handle)
2807 RtldLockState lockstate;
2809 wlock_acquire(rtld_bind_lock, &lockstate);
2810 root = dlcheck(handle);
2812 lock_release(rtld_bind_lock, &lockstate);
2815 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2818 /* Unreference the object and its dependencies. */
2819 root->dl_refcount--;
2821 if (root->refcount == 1) {
2823 * The object will be no longer referenced, so we must unload it.
2824 * First, call the fini functions.
2826 objlist_call_fini(&list_fini, root, &lockstate);
2830 /* Finish cleaning up the newly-unreferenced objects. */
2831 GDB_STATE(RT_DELETE,&root->linkmap);
2832 unload_object(root);
2833 GDB_STATE(RT_CONSISTENT,NULL);
2837 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2838 lock_release(rtld_bind_lock, &lockstate);
2845 char *msg = error_message;
2846 error_message = NULL;
2851 * This function is deprecated and has no effect.
2854 dllockinit(void *context,
2855 void *(*lock_create)(void *context),
2856 void (*rlock_acquire)(void *lock),
2857 void (*wlock_acquire)(void *lock),
2858 void (*lock_release)(void *lock),
2859 void (*lock_destroy)(void *lock),
2860 void (*context_destroy)(void *context))
2862 static void *cur_context;
2863 static void (*cur_context_destroy)(void *);
2865 /* Just destroy the context from the previous call, if necessary. */
2866 if (cur_context_destroy != NULL)
2867 cur_context_destroy(cur_context);
2868 cur_context = context;
2869 cur_context_destroy = context_destroy;
2873 dlopen(const char *name, int mode)
2876 return (rtld_dlopen(name, -1, mode));
2880 fdlopen(int fd, int mode)
2883 return (rtld_dlopen(NULL, fd, mode));
2887 rtld_dlopen(const char *name, int fd, int mode)
2889 RtldLockState lockstate;
2892 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2893 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2894 if (ld_tracing != NULL) {
2895 rlock_acquire(rtld_bind_lock, &lockstate);
2896 if (sigsetjmp(lockstate.env, 0) != 0)
2897 lock_upgrade(rtld_bind_lock, &lockstate);
2898 environ = (char **)*get_program_var_addr("environ", &lockstate);
2899 lock_release(rtld_bind_lock, &lockstate);
2901 lo_flags = RTLD_LO_DLOPEN;
2902 if (mode & RTLD_NODELETE)
2903 lo_flags |= RTLD_LO_NODELETE;
2904 if (mode & RTLD_NOLOAD)
2905 lo_flags |= RTLD_LO_NOLOAD;
2906 if (ld_tracing != NULL)
2907 lo_flags |= RTLD_LO_TRACE;
2909 return (dlopen_object(name, fd, obj_main, lo_flags,
2910 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2914 dlopen_cleanup(Obj_Entry *obj)
2919 if (obj->refcount == 0)
2924 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2925 int mode, RtldLockState *lockstate)
2927 Obj_Entry **old_obj_tail;
2930 RtldLockState mlockstate;
2933 objlist_init(&initlist);
2935 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2936 wlock_acquire(rtld_bind_lock, &mlockstate);
2937 lockstate = &mlockstate;
2939 GDB_STATE(RT_ADD,NULL);
2941 old_obj_tail = obj_tail;
2943 if (name == NULL && fd == -1) {
2947 obj = load_object(name, fd, refobj, lo_flags);
2952 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2953 objlist_push_tail(&list_global, obj);
2954 if (*old_obj_tail != NULL) { /* We loaded something new. */
2955 assert(*old_obj_tail == obj);
2956 result = load_needed_objects(obj,
2957 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2961 result = rtld_verify_versions(&obj->dagmembers);
2962 if (result != -1 && ld_tracing)
2964 if (result == -1 || relocate_object_dag(obj,
2965 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2966 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2968 dlopen_cleanup(obj);
2970 } else if (lo_flags & RTLD_LO_EARLY) {
2972 * Do not call the init functions for early loaded
2973 * filtees. The image is still not initialized enough
2976 * Our object is found by the global object list and
2977 * will be ordered among all init calls done right
2978 * before transferring control to main.
2981 /* Make list of init functions to call. */
2982 initlist_add_objects(obj, &obj->next, &initlist);
2985 * Process all no_delete or global objects here, given
2986 * them own DAGs to prevent their dependencies from being
2987 * unloaded. This has to be done after we have loaded all
2988 * of the dependencies, so that we do not miss any.
2994 * Bump the reference counts for objects on this DAG. If
2995 * this is the first dlopen() call for the object that was
2996 * already loaded as a dependency, initialize the dag
3002 if ((lo_flags & RTLD_LO_TRACE) != 0)
3005 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3006 obj->z_nodelete) && !obj->ref_nodel) {
3007 dbg("obj %s nodelete", obj->path);
3009 obj->z_nodelete = obj->ref_nodel = true;
3013 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3015 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3017 if (!(lo_flags & RTLD_LO_EARLY)) {
3018 map_stacks_exec(lockstate);
3021 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3022 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3024 objlist_clear(&initlist);
3025 dlopen_cleanup(obj);
3026 if (lockstate == &mlockstate)
3027 lock_release(rtld_bind_lock, lockstate);
3031 if (!(lo_flags & RTLD_LO_EARLY)) {
3032 /* Call the init functions. */
3033 objlist_call_init(&initlist, lockstate);
3035 objlist_clear(&initlist);
3036 if (lockstate == &mlockstate)
3037 lock_release(rtld_bind_lock, lockstate);
3040 trace_loaded_objects(obj);
3041 if (lockstate == &mlockstate)
3042 lock_release(rtld_bind_lock, lockstate);
3047 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3051 const Obj_Entry *obj, *defobj;
3054 RtldLockState lockstate;
3062 symlook_init(&req, name);
3064 req.flags = flags | SYMLOOK_IN_PLT;
3065 req.lockstate = &lockstate;
3067 rlock_acquire(rtld_bind_lock, &lockstate);
3068 if (sigsetjmp(lockstate.env, 0) != 0)
3069 lock_upgrade(rtld_bind_lock, &lockstate);
3070 if (handle == NULL || handle == RTLD_NEXT ||
3071 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3073 if ((obj = obj_from_addr(retaddr)) == NULL) {
3074 _rtld_error("Cannot determine caller's shared object");
3075 lock_release(rtld_bind_lock, &lockstate);
3078 if (handle == NULL) { /* Just the caller's shared object. */
3079 res = symlook_obj(&req, obj);
3082 defobj = req.defobj_out;
3084 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3085 handle == RTLD_SELF) { /* ... caller included */
3086 if (handle == RTLD_NEXT)
3088 for (; obj != NULL; obj = obj->next) {
3089 res = symlook_obj(&req, obj);
3092 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3094 defobj = req.defobj_out;
3095 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3101 * Search the dynamic linker itself, and possibly resolve the
3102 * symbol from there. This is how the application links to
3103 * dynamic linker services such as dlopen.
3105 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3106 res = symlook_obj(&req, &obj_rtld);
3109 defobj = req.defobj_out;
3113 assert(handle == RTLD_DEFAULT);
3114 res = symlook_default(&req, obj);
3116 defobj = req.defobj_out;
3121 if ((obj = dlcheck(handle)) == NULL) {
3122 lock_release(rtld_bind_lock, &lockstate);
3126 donelist_init(&donelist);
3127 if (obj->mainprog) {
3128 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3129 res = symlook_global(&req, &donelist);
3132 defobj = req.defobj_out;
3135 * Search the dynamic linker itself, and possibly resolve the
3136 * symbol from there. This is how the application links to
3137 * dynamic linker services such as dlopen.
3139 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3140 res = symlook_obj(&req, &obj_rtld);
3143 defobj = req.defobj_out;
3148 /* Search the whole DAG rooted at the given object. */
3149 res = symlook_list(&req, &obj->dagmembers, &donelist);
3152 defobj = req.defobj_out;
3158 lock_release(rtld_bind_lock, &lockstate);
3161 * The value required by the caller is derived from the value
3162 * of the symbol. For the ia64 architecture, we need to
3163 * construct a function descriptor which the caller can use to
3164 * call the function with the right 'gp' value. For other
3165 * architectures and for non-functions, the value is simply
3166 * the relocated value of the symbol.
3168 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3169 return (make_function_pointer(def, defobj));
3170 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3171 return (rtld_resolve_ifunc(defobj, def));
3172 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3174 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3176 ti.ti_module = defobj->tlsindex;
3177 ti.ti_offset = def->st_value;
3178 return (__tls_get_addr(&ti));
3181 return (defobj->relocbase + def->st_value);
3184 _rtld_error("Undefined symbol \"%s\"", name);
3185 lock_release(rtld_bind_lock, &lockstate);
3190 dlsym(void *handle, const char *name)
3192 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3197 dlfunc(void *handle, const char *name)
3204 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3210 dlvsym(void *handle, const char *name, const char *version)
3214 ventry.name = version;
3216 ventry.hash = elf_hash(version);
3218 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3223 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3225 const Obj_Entry *obj;
3226 RtldLockState lockstate;
3228 rlock_acquire(rtld_bind_lock, &lockstate);
3229 obj = obj_from_addr(addr);
3231 _rtld_error("No shared object contains address");
3232 lock_release(rtld_bind_lock, &lockstate);
3235 rtld_fill_dl_phdr_info(obj, phdr_info);
3236 lock_release(rtld_bind_lock, &lockstate);
3241 dladdr(const void *addr, Dl_info *info)
3243 const Obj_Entry *obj;
3246 unsigned long symoffset;
3247 RtldLockState lockstate;
3249 rlock_acquire(rtld_bind_lock, &lockstate);
3250 obj = obj_from_addr(addr);
3252 _rtld_error("No shared object contains address");
3253 lock_release(rtld_bind_lock, &lockstate);
3256 info->dli_fname = obj->path;
3257 info->dli_fbase = obj->mapbase;
3258 info->dli_saddr = (void *)0;
3259 info->dli_sname = NULL;
3262 * Walk the symbol list looking for the symbol whose address is
3263 * closest to the address sent in.
3265 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3266 def = obj->symtab + symoffset;
3269 * For skip the symbol if st_shndx is either SHN_UNDEF or
3272 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3276 * If the symbol is greater than the specified address, or if it
3277 * is further away from addr than the current nearest symbol,
3280 symbol_addr = obj->relocbase + def->st_value;
3281 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3284 /* Update our idea of the nearest symbol. */
3285 info->dli_sname = obj->strtab + def->st_name;
3286 info->dli_saddr = symbol_addr;
3289 if (info->dli_saddr == addr)
3292 lock_release(rtld_bind_lock, &lockstate);
3297 dlinfo(void *handle, int request, void *p)
3299 const Obj_Entry *obj;
3300 RtldLockState lockstate;
3303 rlock_acquire(rtld_bind_lock, &lockstate);
3305 if (handle == NULL || handle == RTLD_SELF) {
3308 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3309 if ((obj = obj_from_addr(retaddr)) == NULL)
3310 _rtld_error("Cannot determine caller's shared object");
3312 obj = dlcheck(handle);
3315 lock_release(rtld_bind_lock, &lockstate);
3321 case RTLD_DI_LINKMAP:
3322 *((struct link_map const **)p) = &obj->linkmap;
3324 case RTLD_DI_ORIGIN:
3325 error = rtld_dirname(obj->path, p);
3328 case RTLD_DI_SERINFOSIZE:
3329 case RTLD_DI_SERINFO:
3330 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3334 _rtld_error("Invalid request %d passed to dlinfo()", request);
3338 lock_release(rtld_bind_lock, &lockstate);
3344 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3347 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3348 phdr_info->dlpi_name = obj->path;
3349 phdr_info->dlpi_phdr = obj->phdr;
3350 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3351 phdr_info->dlpi_tls_modid = obj->tlsindex;
3352 phdr_info->dlpi_tls_data = obj->tlsinit;
3353 phdr_info->dlpi_adds = obj_loads;
3354 phdr_info->dlpi_subs = obj_loads - obj_count;
3358 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3360 struct dl_phdr_info phdr_info;
3361 const Obj_Entry *obj;
3362 RtldLockState bind_lockstate, phdr_lockstate;
3365 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3366 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3370 for (obj = obj_list; obj != NULL; obj = obj->next) {
3371 rtld_fill_dl_phdr_info(obj, &phdr_info);
3372 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3376 lock_release(rtld_bind_lock, &bind_lockstate);
3377 lock_release(rtld_phdr_lock, &phdr_lockstate);
3383 fill_search_info(const char *dir, size_t dirlen, void *param)
3385 struct fill_search_info_args *arg;
3389 if (arg->request == RTLD_DI_SERINFOSIZE) {
3390 arg->serinfo->dls_cnt ++;
3391 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3393 struct dl_serpath *s_entry;
3395 s_entry = arg->serpath;
3396 s_entry->dls_name = arg->strspace;
3397 s_entry->dls_flags = arg->flags;
3399 strncpy(arg->strspace, dir, dirlen);
3400 arg->strspace[dirlen] = '\0';
3402 arg->strspace += dirlen + 1;
3410 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3412 struct dl_serinfo _info;
3413 struct fill_search_info_args args;
3415 args.request = RTLD_DI_SERINFOSIZE;
3416 args.serinfo = &_info;
3418 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3421 path_enumerate(obj->rpath, fill_search_info, &args);
3422 path_enumerate(ld_library_path, fill_search_info, &args);
3423 path_enumerate(obj->runpath, fill_search_info, &args);
3424 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3425 if (!obj->z_nodeflib)
3426 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3429 if (request == RTLD_DI_SERINFOSIZE) {
3430 info->dls_size = _info.dls_size;
3431 info->dls_cnt = _info.dls_cnt;
3435 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3436 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3440 args.request = RTLD_DI_SERINFO;
3441 args.serinfo = info;
3442 args.serpath = &info->dls_serpath[0];
3443 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3445 args.flags = LA_SER_RUNPATH;
3446 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3449 args.flags = LA_SER_LIBPATH;
3450 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3453 args.flags = LA_SER_RUNPATH;
3454 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3457 args.flags = LA_SER_CONFIG;
3458 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3462 args.flags = LA_SER_DEFAULT;
3463 if (!obj->z_nodeflib &&
3464 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3470 rtld_dirname(const char *path, char *bname)
3474 /* Empty or NULL string gets treated as "." */
3475 if (path == NULL || *path == '\0') {
3481 /* Strip trailing slashes */
3482 endp = path + strlen(path) - 1;
3483 while (endp > path && *endp == '/')
3486 /* Find the start of the dir */
3487 while (endp > path && *endp != '/')
3490 /* Either the dir is "/" or there are no slashes */
3492 bname[0] = *endp == '/' ? '/' : '.';
3498 } while (endp > path && *endp == '/');
3501 if (endp - path + 2 > PATH_MAX)
3503 _rtld_error("Filename is too long: %s", path);
3507 strncpy(bname, path, endp - path + 1);
3508 bname[endp - path + 1] = '\0';
3513 rtld_dirname_abs(const char *path, char *base)
3517 if (realpath(path, base) == NULL)
3519 dbg("%s -> %s", path, base);
3520 last = strrchr(base, '/');
3529 linkmap_add(Obj_Entry *obj)
3531 struct link_map *l = &obj->linkmap;
3532 struct link_map *prev;
3534 obj->linkmap.l_name = obj->path;
3535 obj->linkmap.l_addr = obj->mapbase;
3536 obj->linkmap.l_ld = obj->dynamic;
3538 /* GDB needs load offset on MIPS to use the symbols */
3539 obj->linkmap.l_offs = obj->relocbase;
3542 if (r_debug.r_map == NULL) {
3548 * Scan to the end of the list, but not past the entry for the
3549 * dynamic linker, which we want to keep at the very end.
3551 for (prev = r_debug.r_map;
3552 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3553 prev = prev->l_next)
3556 /* Link in the new entry. */
3558 l->l_next = prev->l_next;
3559 if (l->l_next != NULL)
3560 l->l_next->l_prev = l;
3565 linkmap_delete(Obj_Entry *obj)
3567 struct link_map *l = &obj->linkmap;
3569 if (l->l_prev == NULL) {
3570 if ((r_debug.r_map = l->l_next) != NULL)
3571 l->l_next->l_prev = NULL;
3575 if ((l->l_prev->l_next = l->l_next) != NULL)
3576 l->l_next->l_prev = l->l_prev;
3580 * Function for the debugger to set a breakpoint on to gain control.
3582 * The two parameters allow the debugger to easily find and determine
3583 * what the runtime loader is doing and to whom it is doing it.
3585 * When the loadhook trap is hit (r_debug_state, set at program
3586 * initialization), the arguments can be found on the stack:
3588 * +8 struct link_map *m
3589 * +4 struct r_debug *rd
3593 r_debug_state(struct r_debug* rd, struct link_map *m)
3596 * The following is a hack to force the compiler to emit calls to
3597 * this function, even when optimizing. If the function is empty,
3598 * the compiler is not obliged to emit any code for calls to it,
3599 * even when marked __noinline. However, gdb depends on those
3602 __compiler_membar();
3606 * A function called after init routines have completed. This can be used to
3607 * break before a program's entry routine is called, and can be used when
3608 * main is not available in the symbol table.
3611 _r_debug_postinit(struct link_map *m)
3614 /* See r_debug_state(). */
3615 __compiler_membar();
3619 * Get address of the pointer variable in the main program.
3620 * Prefer non-weak symbol over the weak one.
3622 static const void **
3623 get_program_var_addr(const char *name, RtldLockState *lockstate)
3628 symlook_init(&req, name);
3629 req.lockstate = lockstate;
3630 donelist_init(&donelist);
3631 if (symlook_global(&req, &donelist) != 0)
3633 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3634 return ((const void **)make_function_pointer(req.sym_out,
3636 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3637 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3639 return ((const void **)(req.defobj_out->relocbase +
3640 req.sym_out->st_value));
3644 * Set a pointer variable in the main program to the given value. This
3645 * is used to set key variables such as "environ" before any of the
3646 * init functions are called.
3649 set_program_var(const char *name, const void *value)
3653 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3654 dbg("\"%s\": *%p <-- %p", name, addr, value);
3660 * Search the global objects, including dependencies and main object,
3661 * for the given symbol.
3664 symlook_global(SymLook *req, DoneList *donelist)
3667 const Objlist_Entry *elm;
3670 symlook_init_from_req(&req1, req);
3672 /* Search all objects loaded at program start up. */
3673 if (req->defobj_out == NULL ||
3674 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3675 res = symlook_list(&req1, &list_main, donelist);
3676 if (res == 0 && (req->defobj_out == NULL ||
3677 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3678 req->sym_out = req1.sym_out;
3679 req->defobj_out = req1.defobj_out;
3680 assert(req->defobj_out != NULL);
3684 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3685 STAILQ_FOREACH(elm, &list_global, link) {
3686 if (req->defobj_out != NULL &&
3687 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3689 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3690 if (res == 0 && (req->defobj_out == NULL ||
3691 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3692 req->sym_out = req1.sym_out;
3693 req->defobj_out = req1.defobj_out;
3694 assert(req->defobj_out != NULL);
3698 return (req->sym_out != NULL ? 0 : ESRCH);
3702 * Given a symbol name in a referencing object, find the corresponding
3703 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3704 * no definition was found. Returns a pointer to the Obj_Entry of the
3705 * defining object via the reference parameter DEFOBJ_OUT.
3708 symlook_default(SymLook *req, const Obj_Entry *refobj)
3711 const Objlist_Entry *elm;
3715 donelist_init(&donelist);
3716 symlook_init_from_req(&req1, req);
3718 /* Look first in the referencing object if linked symbolically. */
3719 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3720 res = symlook_obj(&req1, refobj);
3722 req->sym_out = req1.sym_out;
3723 req->defobj_out = req1.defobj_out;
3724 assert(req->defobj_out != NULL);
3728 symlook_global(req, &donelist);
3730 /* Search all dlopened DAGs containing the referencing object. */
3731 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3732 if (req->sym_out != NULL &&
3733 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3735 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3736 if (res == 0 && (req->sym_out == NULL ||
3737 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3738 req->sym_out = req1.sym_out;
3739 req->defobj_out = req1.defobj_out;
3740 assert(req->defobj_out != NULL);
3745 * Search the dynamic linker itself, and possibly resolve the
3746 * symbol from there. This is how the application links to
3747 * dynamic linker services such as dlopen.
3749 if (req->sym_out == NULL ||
3750 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3751 res = symlook_obj(&req1, &obj_rtld);
3753 req->sym_out = req1.sym_out;
3754 req->defobj_out = req1.defobj_out;
3755 assert(req->defobj_out != NULL);
3759 return (req->sym_out != NULL ? 0 : ESRCH);
3763 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3766 const Obj_Entry *defobj;
3767 const Objlist_Entry *elm;
3773 STAILQ_FOREACH(elm, objlist, link) {
3774 if (donelist_check(dlp, elm->obj))
3776 symlook_init_from_req(&req1, req);
3777 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3778 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3780 defobj = req1.defobj_out;
3781 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3788 req->defobj_out = defobj;
3795 * Search the chain of DAGS cointed to by the given Needed_Entry
3796 * for a symbol of the given name. Each DAG is scanned completely
3797 * before advancing to the next one. Returns a pointer to the symbol,
3798 * or NULL if no definition was found.
3801 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3804 const Needed_Entry *n;
3805 const Obj_Entry *defobj;
3811 symlook_init_from_req(&req1, req);
3812 for (n = needed; n != NULL; n = n->next) {
3813 if (n->obj == NULL ||
3814 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3816 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3818 defobj = req1.defobj_out;
3819 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3825 req->defobj_out = defobj;
3832 * Search the symbol table of a single shared object for a symbol of
3833 * the given name and version, if requested. Returns a pointer to the
3834 * symbol, or NULL if no definition was found. If the object is
3835 * filter, return filtered symbol from filtee.
3837 * The symbol's hash value is passed in for efficiency reasons; that
3838 * eliminates many recomputations of the hash value.
3841 symlook_obj(SymLook *req, const Obj_Entry *obj)
3845 int flags, res, mres;
3848 * If there is at least one valid hash at this point, we prefer to
3849 * use the faster GNU version if available.
3851 if (obj->valid_hash_gnu)
3852 mres = symlook_obj1_gnu(req, obj);
3853 else if (obj->valid_hash_sysv)
3854 mres = symlook_obj1_sysv(req, obj);
3859 if (obj->needed_filtees != NULL) {
3860 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3861 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3862 donelist_init(&donelist);
3863 symlook_init_from_req(&req1, req);
3864 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3866 req->sym_out = req1.sym_out;
3867 req->defobj_out = req1.defobj_out;
3871 if (obj->needed_aux_filtees != NULL) {
3872 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3873 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3874 donelist_init(&donelist);
3875 symlook_init_from_req(&req1, req);
3876 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3878 req->sym_out = req1.sym_out;
3879 req->defobj_out = req1.defobj_out;
3887 /* Symbol match routine common to both hash functions */
3889 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3890 const unsigned long symnum)
3893 const Elf_Sym *symp;
3896 symp = obj->symtab + symnum;
3897 strp = obj->strtab + symp->st_name;
3899 switch (ELF_ST_TYPE(symp->st_info)) {
3905 if (symp->st_value == 0)
3909 if (symp->st_shndx != SHN_UNDEF)
3912 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3913 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3920 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3923 if (req->ventry == NULL) {
3924 if (obj->versyms != NULL) {
3925 verndx = VER_NDX(obj->versyms[symnum]);
3926 if (verndx > obj->vernum) {
3928 "%s: symbol %s references wrong version %d",
3929 obj->path, obj->strtab + symnum, verndx);
3933 * If we are not called from dlsym (i.e. this
3934 * is a normal relocation from unversioned
3935 * binary), accept the symbol immediately if
3936 * it happens to have first version after this
3937 * shared object became versioned. Otherwise,
3938 * if symbol is versioned and not hidden,
3939 * remember it. If it is the only symbol with
3940 * this name exported by the shared object, it
3941 * will be returned as a match by the calling
3942 * function. If symbol is global (verndx < 2)
3943 * accept it unconditionally.
3945 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3946 verndx == VER_NDX_GIVEN) {
3947 result->sym_out = symp;
3950 else if (verndx >= VER_NDX_GIVEN) {
3951 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3953 if (result->vsymp == NULL)
3954 result->vsymp = symp;
3960 result->sym_out = symp;
3963 if (obj->versyms == NULL) {
3964 if (object_match_name(obj, req->ventry->name)) {
3965 _rtld_error("%s: object %s should provide version %s "
3966 "for symbol %s", obj_rtld.path, obj->path,
3967 req->ventry->name, obj->strtab + symnum);
3971 verndx = VER_NDX(obj->versyms[symnum]);
3972 if (verndx > obj->vernum) {
3973 _rtld_error("%s: symbol %s references wrong version %d",
3974 obj->path, obj->strtab + symnum, verndx);
3977 if (obj->vertab[verndx].hash != req->ventry->hash ||
3978 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3980 * Version does not match. Look if this is a
3981 * global symbol and if it is not hidden. If
3982 * global symbol (verndx < 2) is available,
3983 * use it. Do not return symbol if we are
3984 * called by dlvsym, because dlvsym looks for
3985 * a specific version and default one is not
3986 * what dlvsym wants.
3988 if ((req->flags & SYMLOOK_DLSYM) ||
3989 (verndx >= VER_NDX_GIVEN) ||
3990 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3994 result->sym_out = symp;
3999 * Search for symbol using SysV hash function.
4000 * obj->buckets is known not to be NULL at this point; the test for this was
4001 * performed with the obj->valid_hash_sysv assignment.
4004 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4006 unsigned long symnum;
4007 Sym_Match_Result matchres;
4009 matchres.sym_out = NULL;
4010 matchres.vsymp = NULL;
4011 matchres.vcount = 0;
4013 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4014 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4015 if (symnum >= obj->nchains)
4016 return (ESRCH); /* Bad object */
4018 if (matched_symbol(req, obj, &matchres, symnum)) {
4019 req->sym_out = matchres.sym_out;
4020 req->defobj_out = obj;
4024 if (matchres.vcount == 1) {
4025 req->sym_out = matchres.vsymp;
4026 req->defobj_out = obj;
4032 /* Search for symbol using GNU hash function */
4034 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4036 Elf_Addr bloom_word;
4037 const Elf32_Word *hashval;
4039 Sym_Match_Result matchres;
4040 unsigned int h1, h2;
4041 unsigned long symnum;
4043 matchres.sym_out = NULL;
4044 matchres.vsymp = NULL;
4045 matchres.vcount = 0;
4047 /* Pick right bitmask word from Bloom filter array */
4048 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4049 obj->maskwords_bm_gnu];
4051 /* Calculate modulus word size of gnu hash and its derivative */
4052 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4053 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4055 /* Filter out the "definitely not in set" queries */
4056 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4059 /* Locate hash chain and corresponding value element*/
4060 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4063 hashval = &obj->chain_zero_gnu[bucket];
4065 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4066 symnum = hashval - obj->chain_zero_gnu;
4067 if (matched_symbol(req, obj, &matchres, symnum)) {
4068 req->sym_out = matchres.sym_out;
4069 req->defobj_out = obj;
4073 } while ((*hashval++ & 1) == 0);
4074 if (matchres.vcount == 1) {
4075 req->sym_out = matchres.vsymp;
4076 req->defobj_out = obj;
4083 trace_loaded_objects(Obj_Entry *obj)
4085 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4088 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4091 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4092 fmt1 = "\t%o => %p (%x)\n";
4094 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4095 fmt2 = "\t%o (%x)\n";
4097 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4099 for (; obj; obj = obj->next) {
4100 Needed_Entry *needed;
4104 if (list_containers && obj->needed != NULL)
4105 rtld_printf("%s:\n", obj->path);
4106 for (needed = obj->needed; needed; needed = needed->next) {
4107 if (needed->obj != NULL) {
4108 if (needed->obj->traced && !list_containers)
4110 needed->obj->traced = true;
4111 path = needed->obj->path;
4115 name = (char *)obj->strtab + needed->name;
4116 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4118 fmt = is_lib ? fmt1 : fmt2;
4119 while ((c = *fmt++) != '\0') {
4145 rtld_putstr(main_local);
4148 rtld_putstr(obj_main->path);
4155 rtld_printf("%d", sodp->sod_major);
4158 rtld_printf("%d", sodp->sod_minor);
4165 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4178 * Unload a dlopened object and its dependencies from memory and from
4179 * our data structures. It is assumed that the DAG rooted in the
4180 * object has already been unreferenced, and that the object has a
4181 * reference count of 0.
4184 unload_object(Obj_Entry *root)
4189 assert(root->refcount == 0);
4192 * Pass over the DAG removing unreferenced objects from
4193 * appropriate lists.
4195 unlink_object(root);
4197 /* Unmap all objects that are no longer referenced. */
4198 linkp = &obj_list->next;
4199 while ((obj = *linkp) != NULL) {
4200 if (obj->refcount == 0) {
4201 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4203 dbg("unloading \"%s\"", obj->path);
4204 unload_filtees(root);
4205 munmap(obj->mapbase, obj->mapsize);
4206 linkmap_delete(obj);
4217 unlink_object(Obj_Entry *root)
4221 if (root->refcount == 0) {
4222 /* Remove the object from the RTLD_GLOBAL list. */
4223 objlist_remove(&list_global, root);
4225 /* Remove the object from all objects' DAG lists. */
4226 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4227 objlist_remove(&elm->obj->dldags, root);
4228 if (elm->obj != root)
4229 unlink_object(elm->obj);
4235 ref_dag(Obj_Entry *root)
4239 assert(root->dag_inited);
4240 STAILQ_FOREACH(elm, &root->dagmembers, link)
4241 elm->obj->refcount++;
4245 unref_dag(Obj_Entry *root)
4249 assert(root->dag_inited);
4250 STAILQ_FOREACH(elm, &root->dagmembers, link)
4251 elm->obj->refcount--;
4255 * Common code for MD __tls_get_addr().
4257 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4259 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4261 Elf_Addr *newdtv, *dtv;
4262 RtldLockState lockstate;
4266 /* Check dtv generation in case new modules have arrived */
4267 if (dtv[0] != tls_dtv_generation) {
4268 wlock_acquire(rtld_bind_lock, &lockstate);
4269 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4271 if (to_copy > tls_max_index)
4272 to_copy = tls_max_index;
4273 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4274 newdtv[0] = tls_dtv_generation;
4275 newdtv[1] = tls_max_index;
4277 lock_release(rtld_bind_lock, &lockstate);
4278 dtv = *dtvp = newdtv;
4281 /* Dynamically allocate module TLS if necessary */
4282 if (dtv[index + 1] == 0) {
4283 /* Signal safe, wlock will block out signals. */
4284 wlock_acquire(rtld_bind_lock, &lockstate);
4285 if (!dtv[index + 1])
4286 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4287 lock_release(rtld_bind_lock, &lockstate);
4289 return ((void *)(dtv[index + 1] + offset));
4293 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4298 /* Check dtv generation in case new modules have arrived */
4299 if (__predict_true(dtv[0] == tls_dtv_generation &&
4300 dtv[index + 1] != 0))
4301 return ((void *)(dtv[index + 1] + offset));
4302 return (tls_get_addr_slow(dtvp, index, offset));
4305 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__)
4308 * Allocate Static TLS using the Variant I method.
4311 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4320 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4323 assert(tcbsize >= TLS_TCB_SIZE);
4324 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4325 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4327 if (oldtcb != NULL) {
4328 memcpy(tls, oldtcb, tls_static_space);
4331 /* Adjust the DTV. */
4333 for (i = 0; i < dtv[1]; i++) {
4334 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4335 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4336 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4340 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4342 dtv[0] = tls_dtv_generation;
4343 dtv[1] = tls_max_index;
4345 for (obj = objs; obj; obj = obj->next) {
4346 if (obj->tlsoffset > 0) {
4347 addr = (Elf_Addr)tls + obj->tlsoffset;
4348 if (obj->tlsinitsize > 0)
4349 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4350 if (obj->tlssize > obj->tlsinitsize)
4351 memset((void*) (addr + obj->tlsinitsize), 0,
4352 obj->tlssize - obj->tlsinitsize);
4353 dtv[obj->tlsindex + 1] = addr;
4362 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4365 Elf_Addr tlsstart, tlsend;
4368 assert(tcbsize >= TLS_TCB_SIZE);
4370 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4371 tlsend = tlsstart + tls_static_space;
4373 dtv = *(Elf_Addr **)tlsstart;
4375 for (i = 0; i < dtvsize; i++) {
4376 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4377 free((void*)dtv[i+2]);
4386 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4389 * Allocate Static TLS using the Variant II method.
4392 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4395 size_t size, ralign;
4397 Elf_Addr *dtv, *olddtv;
4398 Elf_Addr segbase, oldsegbase, addr;
4402 if (tls_static_max_align > ralign)
4403 ralign = tls_static_max_align;
4404 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4406 assert(tcbsize >= 2*sizeof(Elf_Addr));
4407 tls = malloc_aligned(size, ralign);
4408 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4410 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4411 ((Elf_Addr*)segbase)[0] = segbase;
4412 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4414 dtv[0] = tls_dtv_generation;
4415 dtv[1] = tls_max_index;
4419 * Copy the static TLS block over whole.
4421 oldsegbase = (Elf_Addr) oldtls;
4422 memcpy((void *)(segbase - tls_static_space),
4423 (const void *)(oldsegbase - tls_static_space),
4427 * If any dynamic TLS blocks have been created tls_get_addr(),
4430 olddtv = ((Elf_Addr**)oldsegbase)[1];
4431 for (i = 0; i < olddtv[1]; i++) {
4432 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4433 dtv[i+2] = olddtv[i+2];
4439 * We assume that this block was the one we created with
4440 * allocate_initial_tls().
4442 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4444 for (obj = objs; obj; obj = obj->next) {
4445 if (obj->tlsoffset) {
4446 addr = segbase - obj->tlsoffset;
4447 memset((void*) (addr + obj->tlsinitsize),
4448 0, obj->tlssize - obj->tlsinitsize);
4450 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4451 dtv[obj->tlsindex + 1] = addr;
4456 return (void*) segbase;
4460 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4463 size_t size, ralign;
4465 Elf_Addr tlsstart, tlsend;
4468 * Figure out the size of the initial TLS block so that we can
4469 * find stuff which ___tls_get_addr() allocated dynamically.
4472 if (tls_static_max_align > ralign)
4473 ralign = tls_static_max_align;
4474 size = round(tls_static_space, ralign);
4476 dtv = ((Elf_Addr**)tls)[1];
4478 tlsend = (Elf_Addr) tls;
4479 tlsstart = tlsend - size;
4480 for (i = 0; i < dtvsize; i++) {
4481 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4482 free_aligned((void *)dtv[i + 2]);
4486 free_aligned((void *)tlsstart);
4493 * Allocate TLS block for module with given index.
4496 allocate_module_tls(int index)
4501 for (obj = obj_list; obj; obj = obj->next) {
4502 if (obj->tlsindex == index)
4506 _rtld_error("Can't find module with TLS index %d", index);
4510 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4511 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4512 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4518 allocate_tls_offset(Obj_Entry *obj)
4525 if (obj->tlssize == 0) {
4526 obj->tls_done = true;
4530 if (obj->tlsindex == 1)
4531 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4533 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4534 obj->tlssize, obj->tlsalign);
4537 * If we have already fixed the size of the static TLS block, we
4538 * must stay within that size. When allocating the static TLS, we
4539 * leave a small amount of space spare to be used for dynamically
4540 * loading modules which use static TLS.
4542 if (tls_static_space != 0) {
4543 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4545 } else if (obj->tlsalign > tls_static_max_align) {
4546 tls_static_max_align = obj->tlsalign;
4549 tls_last_offset = obj->tlsoffset = off;
4550 tls_last_size = obj->tlssize;
4551 obj->tls_done = true;
4557 free_tls_offset(Obj_Entry *obj)
4561 * If we were the last thing to allocate out of the static TLS
4562 * block, we give our space back to the 'allocator'. This is a
4563 * simplistic workaround to allow libGL.so.1 to be loaded and
4564 * unloaded multiple times.
4566 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4567 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4568 tls_last_offset -= obj->tlssize;
4574 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4577 RtldLockState lockstate;
4579 wlock_acquire(rtld_bind_lock, &lockstate);
4580 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4581 lock_release(rtld_bind_lock, &lockstate);
4586 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4588 RtldLockState lockstate;
4590 wlock_acquire(rtld_bind_lock, &lockstate);
4591 free_tls(tcb, tcbsize, tcbalign);
4592 lock_release(rtld_bind_lock, &lockstate);
4596 object_add_name(Obj_Entry *obj, const char *name)
4602 entry = malloc(sizeof(Name_Entry) + len);
4604 if (entry != NULL) {
4605 strcpy(entry->name, name);
4606 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4611 object_match_name(const Obj_Entry *obj, const char *name)
4615 STAILQ_FOREACH(entry, &obj->names, link) {
4616 if (strcmp(name, entry->name) == 0)
4623 locate_dependency(const Obj_Entry *obj, const char *name)
4625 const Objlist_Entry *entry;
4626 const Needed_Entry *needed;
4628 STAILQ_FOREACH(entry, &list_main, link) {
4629 if (object_match_name(entry->obj, name))
4633 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4634 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4635 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4637 * If there is DT_NEEDED for the name we are looking for,
4638 * we are all set. Note that object might not be found if
4639 * dependency was not loaded yet, so the function can
4640 * return NULL here. This is expected and handled
4641 * properly by the caller.
4643 return (needed->obj);
4646 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4652 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4653 const Elf_Vernaux *vna)
4655 const Elf_Verdef *vd;
4656 const char *vername;
4658 vername = refobj->strtab + vna->vna_name;
4659 vd = depobj->verdef;
4661 _rtld_error("%s: version %s required by %s not defined",
4662 depobj->path, vername, refobj->path);
4666 if (vd->vd_version != VER_DEF_CURRENT) {
4667 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4668 depobj->path, vd->vd_version);
4671 if (vna->vna_hash == vd->vd_hash) {
4672 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4673 ((char *)vd + vd->vd_aux);
4674 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4677 if (vd->vd_next == 0)
4679 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4681 if (vna->vna_flags & VER_FLG_WEAK)
4683 _rtld_error("%s: version %s required by %s not found",
4684 depobj->path, vername, refobj->path);
4689 rtld_verify_object_versions(Obj_Entry *obj)
4691 const Elf_Verneed *vn;
4692 const Elf_Verdef *vd;
4693 const Elf_Verdaux *vda;
4694 const Elf_Vernaux *vna;
4695 const Obj_Entry *depobj;
4696 int maxvernum, vernum;
4698 if (obj->ver_checked)
4700 obj->ver_checked = true;
4704 * Walk over defined and required version records and figure out
4705 * max index used by any of them. Do very basic sanity checking
4709 while (vn != NULL) {
4710 if (vn->vn_version != VER_NEED_CURRENT) {
4711 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4712 obj->path, vn->vn_version);
4715 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4717 vernum = VER_NEED_IDX(vna->vna_other);
4718 if (vernum > maxvernum)
4720 if (vna->vna_next == 0)
4722 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4724 if (vn->vn_next == 0)
4726 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4730 while (vd != NULL) {
4731 if (vd->vd_version != VER_DEF_CURRENT) {
4732 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4733 obj->path, vd->vd_version);
4736 vernum = VER_DEF_IDX(vd->vd_ndx);
4737 if (vernum > maxvernum)
4739 if (vd->vd_next == 0)
4741 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4748 * Store version information in array indexable by version index.
4749 * Verify that object version requirements are satisfied along the
4752 obj->vernum = maxvernum + 1;
4753 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4756 while (vd != NULL) {
4757 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4758 vernum = VER_DEF_IDX(vd->vd_ndx);
4759 assert(vernum <= maxvernum);
4760 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4761 obj->vertab[vernum].hash = vd->vd_hash;
4762 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4763 obj->vertab[vernum].file = NULL;
4764 obj->vertab[vernum].flags = 0;
4766 if (vd->vd_next == 0)
4768 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4772 while (vn != NULL) {
4773 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4776 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4778 if (check_object_provided_version(obj, depobj, vna))
4780 vernum = VER_NEED_IDX(vna->vna_other);
4781 assert(vernum <= maxvernum);
4782 obj->vertab[vernum].hash = vna->vna_hash;
4783 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4784 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4785 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4786 VER_INFO_HIDDEN : 0;
4787 if (vna->vna_next == 0)
4789 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4791 if (vn->vn_next == 0)
4793 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4799 rtld_verify_versions(const Objlist *objlist)
4801 Objlist_Entry *entry;
4805 STAILQ_FOREACH(entry, objlist, link) {
4807 * Skip dummy objects or objects that have their version requirements
4810 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4812 if (rtld_verify_object_versions(entry->obj) == -1) {
4814 if (ld_tracing == NULL)
4818 if (rc == 0 || ld_tracing != NULL)
4819 rc = rtld_verify_object_versions(&obj_rtld);
4824 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4829 vernum = VER_NDX(obj->versyms[symnum]);
4830 if (vernum >= obj->vernum) {
4831 _rtld_error("%s: symbol %s has wrong verneed value %d",
4832 obj->path, obj->strtab + symnum, vernum);
4833 } else if (obj->vertab[vernum].hash != 0) {
4834 return &obj->vertab[vernum];
4841 _rtld_get_stack_prot(void)
4844 return (stack_prot);
4848 _rtld_is_dlopened(void *arg)
4851 RtldLockState lockstate;
4854 rlock_acquire(rtld_bind_lock, &lockstate);
4857 obj = obj_from_addr(arg);
4859 _rtld_error("No shared object contains address");
4860 lock_release(rtld_bind_lock, &lockstate);
4863 res = obj->dlopened ? 1 : 0;
4864 lock_release(rtld_bind_lock, &lockstate);
4869 map_stacks_exec(RtldLockState *lockstate)
4871 void (*thr_map_stacks_exec)(void);
4873 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4875 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4876 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4877 if (thr_map_stacks_exec != NULL) {
4878 stack_prot |= PROT_EXEC;
4879 thr_map_stacks_exec();
4884 symlook_init(SymLook *dst, const char *name)
4887 bzero(dst, sizeof(*dst));
4889 dst->hash = elf_hash(name);
4890 dst->hash_gnu = gnu_hash(name);
4894 symlook_init_from_req(SymLook *dst, const SymLook *src)
4897 dst->name = src->name;
4898 dst->hash = src->hash;
4899 dst->hash_gnu = src->hash_gnu;
4900 dst->ventry = src->ventry;
4901 dst->flags = src->flags;
4902 dst->defobj_out = NULL;
4903 dst->sym_out = NULL;
4904 dst->lockstate = src->lockstate;
4908 * Overrides for libc_pic-provided functions.
4912 __getosreldate(void)
4922 oid[1] = KERN_OSRELDATE;
4924 len = sizeof(osrel);
4925 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4926 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4938 void (*__cleanup)(void);
4939 int __isthreaded = 0;
4940 int _thread_autoinit_dummy_decl = 1;
4943 * No unresolved symbols for rtld.
4946 __pthread_cxa_finalize(struct dl_phdr_info *a)
4951 __stack_chk_fail(void)
4954 _rtld_error("stack overflow detected; terminated");
4957 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
4963 _rtld_error("buffer overflow detected; terminated");
4968 rtld_strerror(int errnum)
4971 if (errnum < 0 || errnum >= sys_nerr)
4972 return ("Unknown error");
4973 return (sys_errlist[errnum]);