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>.
37 #include <sys/param.h>
38 #include <sys/mount.h>
41 #include <sys/sysctl.h>
43 #include <sys/utsname.h>
44 #include <sys/ktrace.h>
60 #include "rtld_printf.h"
64 #define PATH_RTLD "/libexec/ld-elf.so.1"
66 #define PATH_RTLD "/libexec/ld-elf32.so.1"
70 typedef void (*func_ptr_type)();
71 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
74 * Function declarations.
76 static const char *basename(const char *);
77 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
78 const Elf_Dyn **, const Elf_Dyn **);
79 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
81 static void digest_dynamic(Obj_Entry *, int);
82 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
83 static Obj_Entry *dlcheck(void *);
84 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
85 int lo_flags, int mode, RtldLockState *lockstate);
86 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
87 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
88 static bool donelist_check(DoneList *, const Obj_Entry *);
89 static void errmsg_restore(char *);
90 static char *errmsg_save(void);
91 static void *fill_search_info(const char *, size_t, void *);
92 static char *find_library(const char *, const Obj_Entry *);
93 static const char *gethints(bool);
94 static void init_dag(Obj_Entry *);
95 static void init_pagesizes(Elf_Auxinfo **aux_info);
96 static void init_rtld(caddr_t, Elf_Auxinfo **);
97 static void initlist_add_neededs(Needed_Entry *, Objlist *);
98 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
99 static void linkmap_add(Obj_Entry *);
100 static void linkmap_delete(Obj_Entry *);
101 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
102 static void unload_filtees(Obj_Entry *);
103 static int load_needed_objects(Obj_Entry *, int);
104 static int load_preload_objects(void);
105 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
106 static void map_stacks_exec(RtldLockState *);
107 static Obj_Entry *obj_from_addr(const void *);
108 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
109 static void objlist_call_init(Objlist *, RtldLockState *);
110 static void objlist_clear(Objlist *);
111 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
112 static void objlist_init(Objlist *);
113 static void objlist_push_head(Objlist *, Obj_Entry *);
114 static void objlist_push_tail(Objlist *, Obj_Entry *);
115 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
116 static void objlist_remove(Objlist *, Obj_Entry *);
117 static void *path_enumerate(const char *, path_enum_proc, void *);
118 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
119 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
120 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
121 int flags, RtldLockState *lockstate);
122 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
124 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
125 int flags, RtldLockState *lockstate);
126 static int rtld_dirname(const char *, char *);
127 static int rtld_dirname_abs(const char *, char *);
128 static void *rtld_dlopen(const char *name, int fd, int mode);
129 static void rtld_exit(void);
130 static char *search_library_path(const char *, const char *);
131 static const void **get_program_var_addr(const char *, RtldLockState *);
132 static void set_program_var(const char *, const void *);
133 static int symlook_default(SymLook *, const Obj_Entry *refobj);
134 static int symlook_global(SymLook *, DoneList *);
135 static void symlook_init_from_req(SymLook *, const SymLook *);
136 static int symlook_list(SymLook *, const Objlist *, DoneList *);
137 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
138 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
139 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
140 static void trace_loaded_objects(Obj_Entry *);
141 static void unlink_object(Obj_Entry *);
142 static void unload_object(Obj_Entry *);
143 static void unref_dag(Obj_Entry *);
144 static void ref_dag(Obj_Entry *);
145 static char *origin_subst_one(Obj_Entry *, char *, const char *,
147 static char *origin_subst(Obj_Entry *, char *);
148 static bool obj_resolve_origin(Obj_Entry *obj);
149 static void preinit_main(void);
150 static int rtld_verify_versions(const Objlist *);
151 static int rtld_verify_object_versions(Obj_Entry *);
152 static void object_add_name(Obj_Entry *, const char *);
153 static int object_match_name(const Obj_Entry *, const char *);
154 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
155 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
156 struct dl_phdr_info *phdr_info);
157 static uint32_t gnu_hash(const char *);
158 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
159 const unsigned long);
161 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
162 void _r_debug_postinit(struct link_map *) __noinline __exported;
167 static char *error_message; /* Message for dlerror(), or NULL */
168 struct r_debug r_debug __exported; /* for GDB; */
169 static bool libmap_disable; /* Disable libmap */
170 static bool ld_loadfltr; /* Immediate filters processing */
171 static char *libmap_override; /* Maps to use in addition to libmap.conf */
172 static bool trust; /* False for setuid and setgid programs */
173 static bool dangerous_ld_env; /* True if environment variables have been
174 used to affect the libraries loaded */
175 static char *ld_bind_now; /* Environment variable for immediate binding */
176 static char *ld_debug; /* Environment variable for debugging */
177 static char *ld_library_path; /* Environment variable for search path */
178 static char *ld_preload; /* Environment variable for libraries to
180 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
181 static char *ld_tracing; /* Called from ldd to print libs */
182 static char *ld_utrace; /* Use utrace() to log events. */
183 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
184 static Obj_Entry **obj_tail; /* Link field of last object in list */
185 static Obj_Entry *obj_main; /* The main program shared object */
186 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
187 static unsigned int obj_count; /* Number of objects in obj_list */
188 static unsigned int obj_loads; /* Number of objects in obj_list */
190 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
191 STAILQ_HEAD_INITIALIZER(list_global);
192 static Objlist list_main = /* Objects loaded at program startup */
193 STAILQ_HEAD_INITIALIZER(list_main);
194 static Objlist list_fini = /* Objects needing fini() calls */
195 STAILQ_HEAD_INITIALIZER(list_fini);
197 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
199 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
201 extern Elf_Dyn _DYNAMIC;
202 #pragma weak _DYNAMIC
203 #ifndef RTLD_IS_DYNAMIC
204 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
207 int dlclose(void *) __exported;
208 char *dlerror(void) __exported;
209 void *dlopen(const char *, int) __exported;
210 void *fdlopen(int, int) __exported;
211 void *dlsym(void *, const char *) __exported;
212 dlfunc_t dlfunc(void *, const char *) __exported;
213 void *dlvsym(void *, const char *, const char *) __exported;
214 int dladdr(const void *, Dl_info *) __exported;
215 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
216 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
217 int dlinfo(void *, int , void *) __exported;
218 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
219 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
220 int _rtld_get_stack_prot(void) __exported;
221 int _rtld_is_dlopened(void *) __exported;
222 void _rtld_error(const char *, ...) __exported;
224 int npagesizes, osreldate;
227 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
229 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
230 static int max_stack_flags;
233 * Global declarations normally provided by crt1. The dynamic linker is
234 * not built with crt1, so we have to provide them ourselves.
240 * Used to pass argc, argv to init functions.
246 * Globals to control TLS allocation.
248 size_t tls_last_offset; /* Static TLS offset of last module */
249 size_t tls_last_size; /* Static TLS size of last module */
250 size_t tls_static_space; /* Static TLS space allocated */
251 size_t tls_static_max_align;
252 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
253 int tls_max_index = 1; /* Largest module index allocated */
255 bool ld_library_path_rpath = false;
258 * Fill in a DoneList with an allocation large enough to hold all of
259 * the currently-loaded objects. Keep this as a macro since it calls
260 * alloca and we want that to occur within the scope of the caller.
262 #define donelist_init(dlp) \
263 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
264 assert((dlp)->objs != NULL), \
265 (dlp)->num_alloc = obj_count, \
268 #define UTRACE_DLOPEN_START 1
269 #define UTRACE_DLOPEN_STOP 2
270 #define UTRACE_DLCLOSE_START 3
271 #define UTRACE_DLCLOSE_STOP 4
272 #define UTRACE_LOAD_OBJECT 5
273 #define UTRACE_UNLOAD_OBJECT 6
274 #define UTRACE_ADD_RUNDEP 7
275 #define UTRACE_PRELOAD_FINISHED 8
276 #define UTRACE_INIT_CALL 9
277 #define UTRACE_FINI_CALL 10
278 #define UTRACE_DLSYM_START 11
279 #define UTRACE_DLSYM_STOP 12
282 char sig[4]; /* 'RTLD' */
285 void *mapbase; /* Used for 'parent' and 'init/fini' */
287 int refcnt; /* Used for 'mode' */
288 char name[MAXPATHLEN];
291 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
292 if (ld_utrace != NULL) \
293 ld_utrace_log(e, h, mb, ms, r, n); \
297 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
298 int refcnt, const char *name)
300 struct utrace_rtld ut;
308 ut.mapbase = mapbase;
309 ut.mapsize = mapsize;
311 bzero(ut.name, sizeof(ut.name));
313 strlcpy(ut.name, name, sizeof(ut.name));
314 utrace(&ut, sizeof(ut));
318 * Main entry point for dynamic linking. The first argument is the
319 * stack pointer. The stack is expected to be laid out as described
320 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
321 * Specifically, the stack pointer points to a word containing
322 * ARGC. Following that in the stack is a null-terminated sequence
323 * of pointers to argument strings. Then comes a null-terminated
324 * sequence of pointers to environment strings. Finally, there is a
325 * sequence of "auxiliary vector" entries.
327 * The second argument points to a place to store the dynamic linker's
328 * exit procedure pointer and the third to a place to store the main
331 * The return value is the main program's entry point.
334 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
336 Elf_Auxinfo *aux_info[AT_COUNT];
344 Objlist_Entry *entry;
346 Obj_Entry **preload_tail;
347 Obj_Entry *last_interposer;
349 RtldLockState lockstate;
350 char *library_path_rpath;
355 * On entry, the dynamic linker itself has not been relocated yet.
356 * Be very careful not to reference any global data until after
357 * init_rtld has returned. It is OK to reference file-scope statics
358 * and string constants, and to call static and global functions.
361 /* Find the auxiliary vector on the stack. */
364 sp += argc + 1; /* Skip over arguments and NULL terminator */
366 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
368 aux = (Elf_Auxinfo *) sp;
370 /* Digest the auxiliary vector. */
371 for (i = 0; i < AT_COUNT; i++)
373 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
374 if (auxp->a_type < AT_COUNT)
375 aux_info[auxp->a_type] = auxp;
378 /* Initialize and relocate ourselves. */
379 assert(aux_info[AT_BASE] != NULL);
380 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
382 __progname = obj_rtld.path;
383 argv0 = argv[0] != NULL ? argv[0] : "(null)";
388 if (aux_info[AT_CANARY] != NULL &&
389 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
390 i = aux_info[AT_CANARYLEN]->a_un.a_val;
391 if (i > sizeof(__stack_chk_guard))
392 i = sizeof(__stack_chk_guard);
393 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
398 len = sizeof(__stack_chk_guard);
399 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
400 len != sizeof(__stack_chk_guard)) {
401 /* If sysctl was unsuccessful, use the "terminator canary". */
402 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
403 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
404 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
405 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
409 trust = !issetugid();
411 ld_bind_now = getenv(LD_ "BIND_NOW");
413 * If the process is tainted, then we un-set the dangerous environment
414 * variables. The process will be marked as tainted until setuid(2)
415 * is called. If any child process calls setuid(2) we do not want any
416 * future processes to honor the potentially un-safe variables.
419 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
420 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
421 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
422 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
423 _rtld_error("environment corrupt; aborting");
427 ld_debug = getenv(LD_ "DEBUG");
428 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
429 libmap_override = getenv(LD_ "LIBMAP");
430 ld_library_path = getenv(LD_ "LIBRARY_PATH");
431 ld_preload = getenv(LD_ "PRELOAD");
432 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
433 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
434 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
435 if (library_path_rpath != NULL) {
436 if (library_path_rpath[0] == 'y' ||
437 library_path_rpath[0] == 'Y' ||
438 library_path_rpath[0] == '1')
439 ld_library_path_rpath = true;
441 ld_library_path_rpath = false;
443 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
444 (ld_library_path != NULL) || (ld_preload != NULL) ||
445 (ld_elf_hints_path != NULL) || ld_loadfltr;
446 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
447 ld_utrace = getenv(LD_ "UTRACE");
449 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
450 ld_elf_hints_path = _PATH_ELF_HINTS;
452 if (ld_debug != NULL && *ld_debug != '\0')
454 dbg("%s is initialized, base address = %p", __progname,
455 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
456 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
457 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
459 dbg("initializing thread locks");
463 * Load the main program, or process its program header if it is
466 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
467 int fd = aux_info[AT_EXECFD]->a_un.a_val;
468 dbg("loading main program");
469 obj_main = map_object(fd, argv0, NULL);
471 if (obj_main == NULL)
473 max_stack_flags = obj->stack_flags;
474 } else { /* Main program already loaded. */
475 const Elf_Phdr *phdr;
479 dbg("processing main program's program header");
480 assert(aux_info[AT_PHDR] != NULL);
481 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
482 assert(aux_info[AT_PHNUM] != NULL);
483 phnum = aux_info[AT_PHNUM]->a_un.a_val;
484 assert(aux_info[AT_PHENT] != NULL);
485 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
486 assert(aux_info[AT_ENTRY] != NULL);
487 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
488 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
492 if (aux_info[AT_EXECPATH] != 0) {
494 char buf[MAXPATHLEN];
496 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
497 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
498 if (kexecpath[0] == '/')
499 obj_main->path = kexecpath;
500 else if (getcwd(buf, sizeof(buf)) == NULL ||
501 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
502 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
503 obj_main->path = xstrdup(argv0);
505 obj_main->path = xstrdup(buf);
507 dbg("No AT_EXECPATH");
508 obj_main->path = xstrdup(argv0);
510 dbg("obj_main path %s", obj_main->path);
511 obj_main->mainprog = true;
513 if (aux_info[AT_STACKPROT] != NULL &&
514 aux_info[AT_STACKPROT]->a_un.a_val != 0)
515 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
519 * Get the actual dynamic linker pathname from the executable if
520 * possible. (It should always be possible.) That ensures that
521 * gdb will find the right dynamic linker even if a non-standard
524 if (obj_main->interp != NULL &&
525 strcmp(obj_main->interp, obj_rtld.path) != 0) {
527 obj_rtld.path = xstrdup(obj_main->interp);
528 __progname = obj_rtld.path;
532 digest_dynamic(obj_main, 0);
533 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
534 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
535 obj_main->dynsymcount);
537 linkmap_add(obj_main);
538 linkmap_add(&obj_rtld);
540 /* Link the main program into the list of objects. */
541 *obj_tail = obj_main;
542 obj_tail = &obj_main->next;
546 /* Initialize a fake symbol for resolving undefined weak references. */
547 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
548 sym_zero.st_shndx = SHN_UNDEF;
549 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
552 libmap_disable = (bool)lm_init(libmap_override);
554 dbg("loading LD_PRELOAD libraries");
555 if (load_preload_objects() == -1)
557 preload_tail = obj_tail;
559 dbg("loading needed objects");
560 if (load_needed_objects(obj_main, 0) == -1)
563 /* Make a list of all objects loaded at startup. */
564 last_interposer = obj_main;
565 for (obj = obj_list; obj != NULL; obj = obj->next) {
566 if (obj->z_interpose && obj != obj_main) {
567 objlist_put_after(&list_main, last_interposer, obj);
568 last_interposer = obj;
570 objlist_push_tail(&list_main, obj);
575 dbg("checking for required versions");
576 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
579 if (ld_tracing) { /* We're done */
580 trace_loaded_objects(obj_main);
584 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
585 dump_relocations(obj_main);
590 * Processing tls relocations requires having the tls offsets
591 * initialized. Prepare offsets before starting initial
592 * relocation processing.
594 dbg("initializing initial thread local storage offsets");
595 STAILQ_FOREACH(entry, &list_main, link) {
597 * Allocate all the initial objects out of the static TLS
598 * block even if they didn't ask for it.
600 allocate_tls_offset(entry->obj);
603 if (relocate_objects(obj_main,
604 ld_bind_now != NULL && *ld_bind_now != '\0',
605 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
608 dbg("doing copy relocations");
609 if (do_copy_relocations(obj_main) == -1)
612 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
613 dump_relocations(obj_main);
618 * Setup TLS for main thread. This must be done after the
619 * relocations are processed, since tls initialization section
620 * might be the subject for relocations.
622 dbg("initializing initial thread local storage");
623 allocate_initial_tls(obj_list);
625 dbg("initializing key program variables");
626 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
627 set_program_var("environ", env);
628 set_program_var("__elf_aux_vector", aux);
630 /* Make a list of init functions to call. */
631 objlist_init(&initlist);
632 initlist_add_objects(obj_list, preload_tail, &initlist);
634 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
636 map_stacks_exec(NULL);
638 dbg("resolving ifuncs");
639 if (resolve_objects_ifunc(obj_main,
640 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
644 if (!obj_main->crt_no_init) {
646 * Make sure we don't call the main program's init and fini
647 * functions for binaries linked with old crt1 which calls
650 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
651 obj_main->preinit_array = obj_main->init_array =
652 obj_main->fini_array = (Elf_Addr)NULL;
655 wlock_acquire(rtld_bind_lock, &lockstate);
656 if (obj_main->crt_no_init)
658 objlist_call_init(&initlist, &lockstate);
659 _r_debug_postinit(&obj_main->linkmap);
660 objlist_clear(&initlist);
661 dbg("loading filtees");
662 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
663 if (ld_loadfltr || obj->z_loadfltr)
664 load_filtees(obj, 0, &lockstate);
666 lock_release(rtld_bind_lock, &lockstate);
668 dbg("transferring control to program entry point = %p", obj_main->entry);
670 /* Return the exit procedure and the program entry point. */
671 *exit_proc = rtld_exit;
673 return (func_ptr_type) obj_main->entry;
677 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
682 ptr = (void *)make_function_pointer(def, obj);
683 target = ((Elf_Addr (*)(void))ptr)();
684 return ((void *)target);
688 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
692 const Obj_Entry *defobj;
695 RtldLockState lockstate;
697 rlock_acquire(rtld_bind_lock, &lockstate);
698 if (sigsetjmp(lockstate.env, 0) != 0)
699 lock_upgrade(rtld_bind_lock, &lockstate);
701 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
703 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
705 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
706 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
710 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
711 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
713 target = (Elf_Addr)(defobj->relocbase + def->st_value);
715 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
716 defobj->strtab + def->st_name, basename(obj->path),
717 (void *)target, basename(defobj->path));
720 * Write the new contents for the jmpslot. Note that depending on
721 * architecture, the value which we need to return back to the
722 * lazy binding trampoline may or may not be the target
723 * address. The value returned from reloc_jmpslot() is the value
724 * that the trampoline needs.
726 target = reloc_jmpslot(where, target, defobj, obj, rel);
727 lock_release(rtld_bind_lock, &lockstate);
732 * Error reporting function. Use it like printf. If formats the message
733 * into a buffer, and sets things up so that the next call to dlerror()
734 * will return the message.
737 _rtld_error(const char *fmt, ...)
739 static char buf[512];
743 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
749 * Return a dynamically-allocated copy of the current error message, if any.
754 return error_message == NULL ? NULL : xstrdup(error_message);
758 * Restore the current error message from a copy which was previously saved
759 * by errmsg_save(). The copy is freed.
762 errmsg_restore(char *saved_msg)
764 if (saved_msg == NULL)
765 error_message = NULL;
767 _rtld_error("%s", saved_msg);
773 basename(const char *name)
775 const char *p = strrchr(name, '/');
776 return p != NULL ? p + 1 : name;
779 static struct utsname uts;
782 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
783 const char *subst, bool may_free)
785 char *p, *p1, *res, *resp;
786 int subst_len, kw_len, subst_count, old_len, new_len;
791 * First, count the number of the keyword occurences, to
792 * preallocate the final string.
794 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
801 * If the keyword is not found, just return.
803 * Return non-substituted string if resolution failed. We
804 * cannot do anything more reasonable, the failure mode of the
805 * caller is unresolved library anyway.
807 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
808 return (may_free ? real : xstrdup(real));
810 subst = obj->origin_path;
813 * There is indeed something to substitute. Calculate the
814 * length of the resulting string, and allocate it.
816 subst_len = strlen(subst);
817 old_len = strlen(real);
818 new_len = old_len + (subst_len - kw_len) * subst_count;
819 res = xmalloc(new_len + 1);
822 * Now, execute the substitution loop.
824 for (p = real, resp = res, *resp = '\0';;) {
827 /* Copy the prefix before keyword. */
828 memcpy(resp, p, p1 - p);
830 /* Keyword replacement. */
831 memcpy(resp, subst, subst_len);
839 /* Copy to the end of string and finish. */
847 origin_subst(Obj_Entry *obj, char *real)
849 char *res1, *res2, *res3, *res4;
851 if (obj == NULL || !trust)
852 return (xstrdup(real));
853 if (uts.sysname[0] == '\0') {
854 if (uname(&uts) != 0) {
855 _rtld_error("utsname failed: %d", errno);
859 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
860 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
861 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
862 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
869 const char *msg = dlerror();
873 rtld_fdputstr(STDERR_FILENO, msg);
874 rtld_fdputchar(STDERR_FILENO, '\n');
879 * Process a shared object's DYNAMIC section, and save the important
880 * information in its Obj_Entry structure.
883 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
884 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
887 Needed_Entry **needed_tail = &obj->needed;
888 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
889 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
890 const Elf_Hashelt *hashtab;
891 const Elf32_Word *hashval;
892 Elf32_Word bkt, nmaskwords;
894 int plttype = DT_REL;
900 obj->bind_now = false;
901 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
902 switch (dynp->d_tag) {
905 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
909 obj->relsize = dynp->d_un.d_val;
913 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
917 obj->pltrel = (const Elf_Rel *)
918 (obj->relocbase + dynp->d_un.d_ptr);
922 obj->pltrelsize = dynp->d_un.d_val;
926 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
930 obj->relasize = dynp->d_un.d_val;
934 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
938 plttype = dynp->d_un.d_val;
939 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
943 obj->symtab = (const Elf_Sym *)
944 (obj->relocbase + dynp->d_un.d_ptr);
948 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
952 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
956 obj->strsize = dynp->d_un.d_val;
960 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
965 obj->verneednum = dynp->d_un.d_val;
969 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
974 obj->verdefnum = dynp->d_un.d_val;
978 obj->versyms = (const Elf_Versym *)(obj->relocbase +
984 hashtab = (const Elf_Hashelt *)(obj->relocbase +
986 obj->nbuckets = hashtab[0];
987 obj->nchains = hashtab[1];
988 obj->buckets = hashtab + 2;
989 obj->chains = obj->buckets + obj->nbuckets;
990 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
991 obj->buckets != NULL;
997 hashtab = (const Elf_Hashelt *)(obj->relocbase +
999 obj->nbuckets_gnu = hashtab[0];
1000 obj->symndx_gnu = hashtab[1];
1001 nmaskwords = hashtab[2];
1002 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1003 obj->maskwords_bm_gnu = nmaskwords - 1;
1004 obj->shift2_gnu = hashtab[3];
1005 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1006 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1007 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1009 /* Number of bitmask words is required to be power of 2 */
1010 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1011 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1017 Needed_Entry *nep = NEW(Needed_Entry);
1018 nep->name = dynp->d_un.d_val;
1023 needed_tail = &nep->next;
1029 Needed_Entry *nep = NEW(Needed_Entry);
1030 nep->name = dynp->d_un.d_val;
1034 *needed_filtees_tail = nep;
1035 needed_filtees_tail = &nep->next;
1041 Needed_Entry *nep = NEW(Needed_Entry);
1042 nep->name = dynp->d_un.d_val;
1046 *needed_aux_filtees_tail = nep;
1047 needed_aux_filtees_tail = &nep->next;
1052 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1056 obj->textrel = true;
1060 obj->symbolic = true;
1065 * We have to wait until later to process this, because we
1066 * might not have gotten the address of the string table yet.
1076 *dyn_runpath = dynp;
1080 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1083 case DT_PREINIT_ARRAY:
1084 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1087 case DT_PREINIT_ARRAYSZ:
1088 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1092 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1095 case DT_INIT_ARRAYSZ:
1096 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1100 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1104 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1107 case DT_FINI_ARRAYSZ:
1108 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1112 * Don't process DT_DEBUG on MIPS as the dynamic section
1113 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1119 dbg("Filling in DT_DEBUG entry");
1120 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1125 if (dynp->d_un.d_val & DF_ORIGIN)
1126 obj->z_origin = true;
1127 if (dynp->d_un.d_val & DF_SYMBOLIC)
1128 obj->symbolic = true;
1129 if (dynp->d_un.d_val & DF_TEXTREL)
1130 obj->textrel = true;
1131 if (dynp->d_un.d_val & DF_BIND_NOW)
1132 obj->bind_now = true;
1133 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1137 case DT_MIPS_LOCAL_GOTNO:
1138 obj->local_gotno = dynp->d_un.d_val;
1141 case DT_MIPS_SYMTABNO:
1142 obj->symtabno = dynp->d_un.d_val;
1145 case DT_MIPS_GOTSYM:
1146 obj->gotsym = dynp->d_un.d_val;
1149 case DT_MIPS_RLD_MAP:
1150 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1155 if (dynp->d_un.d_val & DF_1_NOOPEN)
1156 obj->z_noopen = true;
1157 if (dynp->d_un.d_val & DF_1_ORIGIN)
1158 obj->z_origin = true;
1159 if (dynp->d_un.d_val & DF_1_GLOBAL)
1160 obj->z_global = true;
1161 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1162 obj->bind_now = true;
1163 if (dynp->d_un.d_val & DF_1_NODELETE)
1164 obj->z_nodelete = true;
1165 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1166 obj->z_loadfltr = true;
1167 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1168 obj->z_interpose = true;
1169 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1170 obj->z_nodeflib = true;
1175 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1182 obj->traced = false;
1184 if (plttype == DT_RELA) {
1185 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1187 obj->pltrelasize = obj->pltrelsize;
1188 obj->pltrelsize = 0;
1191 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1192 if (obj->valid_hash_sysv)
1193 obj->dynsymcount = obj->nchains;
1194 else if (obj->valid_hash_gnu) {
1195 obj->dynsymcount = 0;
1196 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1197 if (obj->buckets_gnu[bkt] == 0)
1199 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1202 while ((*hashval++ & 1u) == 0);
1204 obj->dynsymcount += obj->symndx_gnu;
1209 obj_resolve_origin(Obj_Entry *obj)
1212 if (obj->origin_path != NULL)
1214 obj->origin_path = xmalloc(PATH_MAX);
1215 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1219 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1220 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1223 if (obj->z_origin && !obj_resolve_origin(obj))
1226 if (dyn_runpath != NULL) {
1227 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1228 obj->runpath = origin_subst(obj, obj->runpath);
1229 } else if (dyn_rpath != NULL) {
1230 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1231 obj->rpath = origin_subst(obj, obj->rpath);
1233 if (dyn_soname != NULL)
1234 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1238 digest_dynamic(Obj_Entry *obj, int early)
1240 const Elf_Dyn *dyn_rpath;
1241 const Elf_Dyn *dyn_soname;
1242 const Elf_Dyn *dyn_runpath;
1244 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1245 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1249 * Process a shared object's program header. This is used only for the
1250 * main program, when the kernel has already loaded the main program
1251 * into memory before calling the dynamic linker. It creates and
1252 * returns an Obj_Entry structure.
1255 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1258 const Elf_Phdr *phlimit = phdr + phnum;
1260 Elf_Addr note_start, note_end;
1264 for (ph = phdr; ph < phlimit; ph++) {
1265 if (ph->p_type != PT_PHDR)
1269 obj->phsize = ph->p_memsz;
1270 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1274 obj->stack_flags = PF_X | PF_R | PF_W;
1276 for (ph = phdr; ph < phlimit; ph++) {
1277 switch (ph->p_type) {
1280 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1284 if (nsegs == 0) { /* First load segment */
1285 obj->vaddrbase = trunc_page(ph->p_vaddr);
1286 obj->mapbase = obj->vaddrbase + obj->relocbase;
1287 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1289 } else { /* Last load segment */
1290 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1297 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1302 obj->tlssize = ph->p_memsz;
1303 obj->tlsalign = ph->p_align;
1304 obj->tlsinitsize = ph->p_filesz;
1305 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1309 obj->stack_flags = ph->p_flags;
1313 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1314 obj->relro_size = round_page(ph->p_memsz);
1318 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1319 note_end = note_start + ph->p_filesz;
1320 digest_notes(obj, note_start, note_end);
1325 _rtld_error("%s: too few PT_LOAD segments", path);
1334 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1336 const Elf_Note *note;
1337 const char *note_name;
1340 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1341 note = (const Elf_Note *)((const char *)(note + 1) +
1342 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1343 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1344 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1345 note->n_descsz != sizeof(int32_t))
1347 if (note->n_type != ABI_NOTETYPE &&
1348 note->n_type != CRT_NOINIT_NOTETYPE)
1350 note_name = (const char *)(note + 1);
1351 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1352 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1354 switch (note->n_type) {
1356 /* FreeBSD osrel note */
1357 p = (uintptr_t)(note + 1);
1358 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1359 obj->osrel = *(const int32_t *)(p);
1360 dbg("note osrel %d", obj->osrel);
1362 case CRT_NOINIT_NOTETYPE:
1363 /* FreeBSD 'crt does not call init' note */
1364 obj->crt_no_init = true;
1365 dbg("note crt_no_init");
1372 dlcheck(void *handle)
1376 for (obj = obj_list; obj != NULL; obj = obj->next)
1377 if (obj == (Obj_Entry *) handle)
1380 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1381 _rtld_error("Invalid shared object handle %p", handle);
1388 * If the given object is already in the donelist, return true. Otherwise
1389 * add the object to the list and return false.
1392 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1396 for (i = 0; i < dlp->num_used; i++)
1397 if (dlp->objs[i] == obj)
1400 * Our donelist allocation should always be sufficient. But if
1401 * our threads locking isn't working properly, more shared objects
1402 * could have been loaded since we allocated the list. That should
1403 * never happen, but we'll handle it properly just in case it does.
1405 if (dlp->num_used < dlp->num_alloc)
1406 dlp->objs[dlp->num_used++] = obj;
1411 * Hash function for symbol table lookup. Don't even think about changing
1412 * this. It is specified by the System V ABI.
1415 elf_hash(const char *name)
1417 const unsigned char *p = (const unsigned char *) name;
1418 unsigned long h = 0;
1421 while (*p != '\0') {
1422 h = (h << 4) + *p++;
1423 if ((g = h & 0xf0000000) != 0)
1431 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1432 * unsigned in case it's implemented with a wider type.
1435 gnu_hash(const char *s)
1441 for (c = *s; c != '\0'; c = *++s)
1443 return (h & 0xffffffff);
1447 * Find the library with the given name, and return its full pathname.
1448 * The returned string is dynamically allocated. Generates an error
1449 * message and returns NULL if the library cannot be found.
1451 * If the second argument is non-NULL, then it refers to an already-
1452 * loaded shared object, whose library search path will be searched.
1454 * The search order is:
1455 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1456 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1458 * DT_RUNPATH in the referencing file
1459 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1461 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1463 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1466 find_library(const char *xname, const Obj_Entry *refobj)
1470 bool nodeflib, objgiven;
1472 objgiven = refobj != NULL;
1473 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1474 if (xname[0] != '/' && !trust) {
1475 _rtld_error("Absolute pathname required for shared object \"%s\"",
1479 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1480 __DECONST(char *, xname)));
1483 if (libmap_disable || !objgiven ||
1484 (name = lm_find(refobj->path, xname)) == NULL)
1485 name = (char *)xname;
1487 dbg(" Searching for \"%s\"", name);
1490 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1491 * back to pre-conforming behaviour if user requested so with
1492 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1495 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1496 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1498 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1499 (pathname = search_library_path(name, gethints(false))) != NULL ||
1500 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1503 nodeflib = objgiven ? refobj->z_nodeflib : false;
1505 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1506 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1507 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1508 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1510 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1511 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1512 (objgiven && !nodeflib &&
1513 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1517 if (objgiven && refobj->path != NULL) {
1518 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1519 name, basename(refobj->path));
1521 _rtld_error("Shared object \"%s\" not found", name);
1527 * Given a symbol number in a referencing object, find the corresponding
1528 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1529 * no definition was found. Returns a pointer to the Obj_Entry of the
1530 * defining object via the reference parameter DEFOBJ_OUT.
1533 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1534 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1535 RtldLockState *lockstate)
1539 const Obj_Entry *defobj;
1545 * If we have already found this symbol, get the information from
1548 if (symnum >= refobj->dynsymcount)
1549 return NULL; /* Bad object */
1550 if (cache != NULL && cache[symnum].sym != NULL) {
1551 *defobj_out = cache[symnum].obj;
1552 return cache[symnum].sym;
1555 ref = refobj->symtab + symnum;
1556 name = refobj->strtab + ref->st_name;
1561 * We don't have to do a full scale lookup if the symbol is local.
1562 * We know it will bind to the instance in this load module; to
1563 * which we already have a pointer (ie ref). By not doing a lookup,
1564 * we not only improve performance, but it also avoids unresolvable
1565 * symbols when local symbols are not in the hash table. This has
1566 * been seen with the ia64 toolchain.
1568 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1569 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1570 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1573 symlook_init(&req, name);
1575 req.ventry = fetch_ventry(refobj, symnum);
1576 req.lockstate = lockstate;
1577 res = symlook_default(&req, refobj);
1580 defobj = req.defobj_out;
1588 * If we found no definition and the reference is weak, treat the
1589 * symbol as having the value zero.
1591 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1597 *defobj_out = defobj;
1598 /* Record the information in the cache to avoid subsequent lookups. */
1599 if (cache != NULL) {
1600 cache[symnum].sym = def;
1601 cache[symnum].obj = defobj;
1604 if (refobj != &obj_rtld)
1605 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1611 * Return the search path from the ldconfig hints file, reading it if
1612 * necessary. If nostdlib is true, then the default search paths are
1613 * not added to result.
1615 * Returns NULL if there are problems with the hints file,
1616 * or if the search path there is empty.
1619 gethints(bool nostdlib)
1621 static char *hints, *filtered_path;
1622 struct elfhints_hdr hdr;
1623 struct fill_search_info_args sargs, hargs;
1624 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1625 struct dl_serpath *SLPpath, *hintpath;
1627 unsigned int SLPndx, hintndx, fndx, fcount;
1632 /* First call, read the hints file */
1633 if (hints == NULL) {
1634 /* Keep from trying again in case the hints file is bad. */
1637 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1639 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1640 hdr.magic != ELFHINTS_MAGIC ||
1645 p = xmalloc(hdr.dirlistlen + 1);
1646 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1647 read(fd, p, hdr.dirlistlen + 1) !=
1648 (ssize_t)hdr.dirlistlen + 1) {
1658 * If caller agreed to receive list which includes the default
1659 * paths, we are done. Otherwise, if we still did not
1660 * calculated filtered result, do it now.
1663 return (hints[0] != '\0' ? hints : NULL);
1664 if (filtered_path != NULL)
1668 * Obtain the list of all configured search paths, and the
1669 * list of the default paths.
1671 * First estimate the size of the results.
1673 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1675 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1678 sargs.request = RTLD_DI_SERINFOSIZE;
1679 sargs.serinfo = &smeta;
1680 hargs.request = RTLD_DI_SERINFOSIZE;
1681 hargs.serinfo = &hmeta;
1683 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1684 path_enumerate(p, fill_search_info, &hargs);
1686 SLPinfo = xmalloc(smeta.dls_size);
1687 hintinfo = xmalloc(hmeta.dls_size);
1690 * Next fetch both sets of paths.
1692 sargs.request = RTLD_DI_SERINFO;
1693 sargs.serinfo = SLPinfo;
1694 sargs.serpath = &SLPinfo->dls_serpath[0];
1695 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1697 hargs.request = RTLD_DI_SERINFO;
1698 hargs.serinfo = hintinfo;
1699 hargs.serpath = &hintinfo->dls_serpath[0];
1700 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1702 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1703 path_enumerate(p, fill_search_info, &hargs);
1706 * Now calculate the difference between two sets, by excluding
1707 * standard paths from the full set.
1711 filtered_path = xmalloc(hdr.dirlistlen + 1);
1712 hintpath = &hintinfo->dls_serpath[0];
1713 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1715 SLPpath = &SLPinfo->dls_serpath[0];
1717 * Check each standard path against current.
1719 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1720 /* matched, skip the path */
1721 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1729 * Not matched against any standard path, add the path
1730 * to result. Separate consequtive paths with ':'.
1733 filtered_path[fndx] = ':';
1737 flen = strlen(hintpath->dls_name);
1738 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1741 filtered_path[fndx] = '\0';
1747 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1751 init_dag(Obj_Entry *root)
1753 const Needed_Entry *needed;
1754 const Objlist_Entry *elm;
1757 if (root->dag_inited)
1759 donelist_init(&donelist);
1761 /* Root object belongs to own DAG. */
1762 objlist_push_tail(&root->dldags, root);
1763 objlist_push_tail(&root->dagmembers, root);
1764 donelist_check(&donelist, root);
1767 * Add dependencies of root object to DAG in breadth order
1768 * by exploiting the fact that each new object get added
1769 * to the tail of the dagmembers list.
1771 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1772 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1773 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1775 objlist_push_tail(&needed->obj->dldags, root);
1776 objlist_push_tail(&root->dagmembers, needed->obj);
1779 root->dag_inited = true;
1783 process_z(Obj_Entry *root)
1785 const Objlist_Entry *elm;
1789 * Walk over object DAG and process every dependent object
1790 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
1791 * to grow their own DAG.
1793 * For DF_1_GLOBAL, DAG is required for symbol lookups in
1794 * symlook_global() to work.
1796 * For DF_1_NODELETE, the DAG should have its reference upped.
1798 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1802 if (obj->z_nodelete && !obj->ref_nodel) {
1803 dbg("obj %s -z nodelete", obj->path);
1806 obj->ref_nodel = true;
1808 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
1809 dbg("obj %s -z global", obj->path);
1810 objlist_push_tail(&list_global, obj);
1816 * Initialize the dynamic linker. The argument is the address at which
1817 * the dynamic linker has been mapped into memory. The primary task of
1818 * this function is to relocate the dynamic linker.
1821 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1823 Obj_Entry objtmp; /* Temporary rtld object */
1824 const Elf_Dyn *dyn_rpath;
1825 const Elf_Dyn *dyn_soname;
1826 const Elf_Dyn *dyn_runpath;
1828 #ifdef RTLD_INIT_PAGESIZES_EARLY
1829 /* The page size is required by the dynamic memory allocator. */
1830 init_pagesizes(aux_info);
1834 * Conjure up an Obj_Entry structure for the dynamic linker.
1836 * The "path" member can't be initialized yet because string constants
1837 * cannot yet be accessed. Below we will set it correctly.
1839 memset(&objtmp, 0, sizeof(objtmp));
1842 objtmp.mapbase = mapbase;
1844 objtmp.relocbase = mapbase;
1846 if (RTLD_IS_DYNAMIC()) {
1847 objtmp.dynamic = rtld_dynamic(&objtmp);
1848 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1849 assert(objtmp.needed == NULL);
1850 #if !defined(__mips__)
1851 /* MIPS has a bogus DT_TEXTREL. */
1852 assert(!objtmp.textrel);
1856 * Temporarily put the dynamic linker entry into the object list, so
1857 * that symbols can be found.
1860 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1863 /* Initialize the object list. */
1864 obj_tail = &obj_list;
1866 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1867 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1869 #ifndef RTLD_INIT_PAGESIZES_EARLY
1870 /* The page size is required by the dynamic memory allocator. */
1871 init_pagesizes(aux_info);
1874 if (aux_info[AT_OSRELDATE] != NULL)
1875 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1877 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1879 /* Replace the path with a dynamically allocated copy. */
1880 obj_rtld.path = xstrdup(PATH_RTLD);
1882 r_debug.r_brk = r_debug_state;
1883 r_debug.r_state = RT_CONSISTENT;
1887 * Retrieve the array of supported page sizes. The kernel provides the page
1888 * sizes in increasing order.
1891 init_pagesizes(Elf_Auxinfo **aux_info)
1893 static size_t psa[MAXPAGESIZES];
1897 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1899 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1900 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1903 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1906 /* As a fallback, retrieve the base page size. */
1907 size = sizeof(psa[0]);
1908 if (aux_info[AT_PAGESZ] != NULL) {
1909 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1913 mib[1] = HW_PAGESIZE;
1917 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1918 _rtld_error("sysctl for hw.pagesize(s) failed");
1924 npagesizes = size / sizeof(pagesizes[0]);
1925 /* Discard any invalid entries at the end of the array. */
1926 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1931 * Add the init functions from a needed object list (and its recursive
1932 * needed objects) to "list". This is not used directly; it is a helper
1933 * function for initlist_add_objects(). The write lock must be held
1934 * when this function is called.
1937 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1939 /* Recursively process the successor needed objects. */
1940 if (needed->next != NULL)
1941 initlist_add_neededs(needed->next, list);
1943 /* Process the current needed object. */
1944 if (needed->obj != NULL)
1945 initlist_add_objects(needed->obj, &needed->obj->next, list);
1949 * Scan all of the DAGs rooted in the range of objects from "obj" to
1950 * "tail" and add their init functions to "list". This recurses over
1951 * the DAGs and ensure the proper init ordering such that each object's
1952 * needed libraries are initialized before the object itself. At the
1953 * same time, this function adds the objects to the global finalization
1954 * list "list_fini" in the opposite order. The write lock must be
1955 * held when this function is called.
1958 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1961 if (obj->init_scanned || obj->init_done)
1963 obj->init_scanned = true;
1965 /* Recursively process the successor objects. */
1966 if (&obj->next != tail)
1967 initlist_add_objects(obj->next, tail, list);
1969 /* Recursively process the needed objects. */
1970 if (obj->needed != NULL)
1971 initlist_add_neededs(obj->needed, list);
1972 if (obj->needed_filtees != NULL)
1973 initlist_add_neededs(obj->needed_filtees, list);
1974 if (obj->needed_aux_filtees != NULL)
1975 initlist_add_neededs(obj->needed_aux_filtees, list);
1977 /* Add the object to the init list. */
1978 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1979 obj->init_array != (Elf_Addr)NULL)
1980 objlist_push_tail(list, obj);
1982 /* Add the object to the global fini list in the reverse order. */
1983 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1984 && !obj->on_fini_list) {
1985 objlist_push_head(&list_fini, obj);
1986 obj->on_fini_list = true;
1991 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1995 free_needed_filtees(Needed_Entry *n)
1997 Needed_Entry *needed, *needed1;
1999 for (needed = n; needed != NULL; needed = needed->next) {
2000 if (needed->obj != NULL) {
2001 dlclose(needed->obj);
2005 for (needed = n; needed != NULL; needed = needed1) {
2006 needed1 = needed->next;
2012 unload_filtees(Obj_Entry *obj)
2015 free_needed_filtees(obj->needed_filtees);
2016 obj->needed_filtees = NULL;
2017 free_needed_filtees(obj->needed_aux_filtees);
2018 obj->needed_aux_filtees = NULL;
2019 obj->filtees_loaded = false;
2023 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2024 RtldLockState *lockstate)
2027 for (; needed != NULL; needed = needed->next) {
2028 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2029 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2030 RTLD_LOCAL, lockstate);
2035 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2038 lock_restart_for_upgrade(lockstate);
2039 if (!obj->filtees_loaded) {
2040 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2041 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2042 obj->filtees_loaded = true;
2047 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2051 for (; needed != NULL; needed = needed->next) {
2052 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2053 flags & ~RTLD_LO_NOLOAD);
2054 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2061 * Given a shared object, traverse its list of needed objects, and load
2062 * each of them. Returns 0 on success. Generates an error message and
2063 * returns -1 on failure.
2066 load_needed_objects(Obj_Entry *first, int flags)
2070 for (obj = first; obj != NULL; obj = obj->next) {
2071 if (process_needed(obj, obj->needed, flags) == -1)
2078 load_preload_objects(void)
2080 char *p = ld_preload;
2082 static const char delim[] = " \t:;";
2087 p += strspn(p, delim);
2088 while (*p != '\0') {
2089 size_t len = strcspn(p, delim);
2094 obj = load_object(p, -1, NULL, 0);
2096 return -1; /* XXX - cleanup */
2097 obj->z_interpose = true;
2100 p += strspn(p, delim);
2102 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2107 printable_path(const char *path)
2110 return (path == NULL ? "<unknown>" : path);
2114 * Load a shared object into memory, if it is not already loaded. The
2115 * object may be specified by name or by user-supplied file descriptor
2116 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2119 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2123 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2131 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2132 if (object_match_name(obj, name))
2136 path = find_library(name, refobj);
2143 * If we didn't find a match by pathname, or the name is not
2144 * supplied, open the file and check again by device and inode.
2145 * This avoids false mismatches caused by multiple links or ".."
2148 * To avoid a race, we open the file and use fstat() rather than
2153 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2154 _rtld_error("Cannot open \"%s\"", path);
2159 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2161 _rtld_error("Cannot dup fd");
2166 if (fstat(fd, &sb) == -1) {
2167 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2172 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2173 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2175 if (obj != NULL && name != NULL) {
2176 object_add_name(obj, name);
2181 if (flags & RTLD_LO_NOLOAD) {
2187 /* First use of this object, so we must map it in */
2188 obj = do_load_object(fd, name, path, &sb, flags);
2197 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2204 * but first, make sure that environment variables haven't been
2205 * used to circumvent the noexec flag on a filesystem.
2207 if (dangerous_ld_env) {
2208 if (fstatfs(fd, &fs) != 0) {
2209 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2212 if (fs.f_flags & MNT_NOEXEC) {
2213 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2217 dbg("loading \"%s\"", printable_path(path));
2218 obj = map_object(fd, printable_path(path), sbp);
2223 * If DT_SONAME is present in the object, digest_dynamic2 already
2224 * added it to the object names.
2227 object_add_name(obj, name);
2229 digest_dynamic(obj, 0);
2230 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2231 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2232 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2234 dbg("refusing to load non-loadable \"%s\"", obj->path);
2235 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2236 munmap(obj->mapbase, obj->mapsize);
2241 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2243 obj_tail = &obj->next;
2246 linkmap_add(obj); /* for GDB & dlinfo() */
2247 max_stack_flags |= obj->stack_flags;
2249 dbg(" %p .. %p: %s", obj->mapbase,
2250 obj->mapbase + obj->mapsize - 1, obj->path);
2252 dbg(" WARNING: %s has impure text", obj->path);
2253 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2260 obj_from_addr(const void *addr)
2264 for (obj = obj_list; obj != NULL; obj = obj->next) {
2265 if (addr < (void *) obj->mapbase)
2267 if (addr < (void *) (obj->mapbase + obj->mapsize))
2276 Elf_Addr *preinit_addr;
2279 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2280 if (preinit_addr == NULL)
2283 for (index = 0; index < obj_main->preinit_array_num; index++) {
2284 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2285 dbg("calling preinit function for %s at %p", obj_main->path,
2286 (void *)preinit_addr[index]);
2287 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2288 0, 0, obj_main->path);
2289 call_init_pointer(obj_main, preinit_addr[index]);
2295 * Call the finalization functions for each of the objects in "list"
2296 * belonging to the DAG of "root" and referenced once. If NULL "root"
2297 * is specified, every finalization function will be called regardless
2298 * of the reference count and the list elements won't be freed. All of
2299 * the objects are expected to have non-NULL fini functions.
2302 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2306 Elf_Addr *fini_addr;
2309 assert(root == NULL || root->refcount == 1);
2312 * Preserve the current error message since a fini function might
2313 * call into the dynamic linker and overwrite it.
2315 saved_msg = errmsg_save();
2317 STAILQ_FOREACH(elm, list, link) {
2318 if (root != NULL && (elm->obj->refcount != 1 ||
2319 objlist_find(&root->dagmembers, elm->obj) == NULL))
2321 /* Remove object from fini list to prevent recursive invocation. */
2322 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2324 * XXX: If a dlopen() call references an object while the
2325 * fini function is in progress, we might end up trying to
2326 * unload the referenced object in dlclose() or the object
2327 * won't be unloaded although its fini function has been
2330 lock_release(rtld_bind_lock, lockstate);
2333 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2334 * When this happens, DT_FINI_ARRAY is processed first.
2336 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2337 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2338 for (index = elm->obj->fini_array_num - 1; index >= 0;
2340 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2341 dbg("calling fini function for %s at %p",
2342 elm->obj->path, (void *)fini_addr[index]);
2343 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2344 (void *)fini_addr[index], 0, 0, elm->obj->path);
2345 call_initfini_pointer(elm->obj, fini_addr[index]);
2349 if (elm->obj->fini != (Elf_Addr)NULL) {
2350 dbg("calling fini function for %s at %p", elm->obj->path,
2351 (void *)elm->obj->fini);
2352 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2353 0, 0, elm->obj->path);
2354 call_initfini_pointer(elm->obj, elm->obj->fini);
2356 wlock_acquire(rtld_bind_lock, lockstate);
2357 /* No need to free anything if process is going down. */
2361 * We must restart the list traversal after every fini call
2362 * because a dlclose() call from the fini function or from
2363 * another thread might have modified the reference counts.
2367 } while (elm != NULL);
2368 errmsg_restore(saved_msg);
2372 * Call the initialization functions for each of the objects in
2373 * "list". All of the objects are expected to have non-NULL init
2377 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2382 Elf_Addr *init_addr;
2386 * Clean init_scanned flag so that objects can be rechecked and
2387 * possibly initialized earlier if any of vectors called below
2388 * cause the change by using dlopen.
2390 for (obj = obj_list; obj != NULL; obj = obj->next)
2391 obj->init_scanned = false;
2394 * Preserve the current error message since an init function might
2395 * call into the dynamic linker and overwrite it.
2397 saved_msg = errmsg_save();
2398 STAILQ_FOREACH(elm, list, link) {
2399 if (elm->obj->init_done) /* Initialized early. */
2402 * Race: other thread might try to use this object before current
2403 * one completes the initilization. Not much can be done here
2404 * without better locking.
2406 elm->obj->init_done = true;
2407 lock_release(rtld_bind_lock, lockstate);
2410 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2411 * When this happens, DT_INIT is processed first.
2413 if (elm->obj->init != (Elf_Addr)NULL) {
2414 dbg("calling init function for %s at %p", elm->obj->path,
2415 (void *)elm->obj->init);
2416 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2417 0, 0, elm->obj->path);
2418 call_initfini_pointer(elm->obj, elm->obj->init);
2420 init_addr = (Elf_Addr *)elm->obj->init_array;
2421 if (init_addr != NULL) {
2422 for (index = 0; index < elm->obj->init_array_num; index++) {
2423 if (init_addr[index] != 0 && init_addr[index] != 1) {
2424 dbg("calling init function for %s at %p", elm->obj->path,
2425 (void *)init_addr[index]);
2426 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2427 (void *)init_addr[index], 0, 0, elm->obj->path);
2428 call_init_pointer(elm->obj, init_addr[index]);
2432 wlock_acquire(rtld_bind_lock, lockstate);
2434 errmsg_restore(saved_msg);
2438 objlist_clear(Objlist *list)
2442 while (!STAILQ_EMPTY(list)) {
2443 elm = STAILQ_FIRST(list);
2444 STAILQ_REMOVE_HEAD(list, link);
2449 static Objlist_Entry *
2450 objlist_find(Objlist *list, const Obj_Entry *obj)
2454 STAILQ_FOREACH(elm, list, link)
2455 if (elm->obj == obj)
2461 objlist_init(Objlist *list)
2467 objlist_push_head(Objlist *list, Obj_Entry *obj)
2471 elm = NEW(Objlist_Entry);
2473 STAILQ_INSERT_HEAD(list, elm, link);
2477 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2481 elm = NEW(Objlist_Entry);
2483 STAILQ_INSERT_TAIL(list, elm, link);
2487 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2489 Objlist_Entry *elm, *listelm;
2491 STAILQ_FOREACH(listelm, list, link) {
2492 if (listelm->obj == listobj)
2495 elm = NEW(Objlist_Entry);
2497 if (listelm != NULL)
2498 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2500 STAILQ_INSERT_TAIL(list, elm, link);
2504 objlist_remove(Objlist *list, Obj_Entry *obj)
2508 if ((elm = objlist_find(list, obj)) != NULL) {
2509 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2515 * Relocate dag rooted in the specified object.
2516 * Returns 0 on success, or -1 on failure.
2520 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2521 int flags, RtldLockState *lockstate)
2527 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2528 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2537 * Relocate single object.
2538 * Returns 0 on success, or -1 on failure.
2541 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2542 int flags, RtldLockState *lockstate)
2547 obj->relocated = true;
2549 dbg("relocating \"%s\"", obj->path);
2551 if (obj->symtab == NULL || obj->strtab == NULL ||
2552 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2553 _rtld_error("%s: Shared object has no run-time symbol table",
2559 /* There are relocations to the write-protected text segment. */
2560 if (mprotect(obj->mapbase, obj->textsize,
2561 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2562 _rtld_error("%s: Cannot write-enable text segment: %s",
2563 obj->path, rtld_strerror(errno));
2568 /* Process the non-PLT non-IFUNC relocations. */
2569 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2572 if (obj->textrel) { /* Re-protected the text segment. */
2573 if (mprotect(obj->mapbase, obj->textsize,
2574 PROT_READ|PROT_EXEC) == -1) {
2575 _rtld_error("%s: Cannot write-protect text segment: %s",
2576 obj->path, rtld_strerror(errno));
2581 /* Set the special PLT or GOT entries. */
2584 /* Process the PLT relocations. */
2585 if (reloc_plt(obj) == -1)
2587 /* Relocate the jump slots if we are doing immediate binding. */
2588 if (obj->bind_now || bind_now)
2589 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2593 * Process the non-PLT IFUNC relocations. The relocations are
2594 * processed in two phases, because IFUNC resolvers may
2595 * reference other symbols, which must be readily processed
2596 * before resolvers are called.
2598 if (obj->non_plt_gnu_ifunc &&
2599 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2602 if (obj->relro_size > 0) {
2603 if (mprotect(obj->relro_page, obj->relro_size,
2605 _rtld_error("%s: Cannot enforce relro protection: %s",
2606 obj->path, rtld_strerror(errno));
2612 * Set up the magic number and version in the Obj_Entry. These
2613 * were checked in the crt1.o from the original ElfKit, so we
2614 * set them for backward compatibility.
2616 obj->magic = RTLD_MAGIC;
2617 obj->version = RTLD_VERSION;
2623 * Relocate newly-loaded shared objects. The argument is a pointer to
2624 * the Obj_Entry for the first such object. All objects from the first
2625 * to the end of the list of objects are relocated. Returns 0 on success,
2629 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2630 int flags, RtldLockState *lockstate)
2635 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2636 error = relocate_object(obj, bind_now, rtldobj, flags,
2645 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2646 * referencing STT_GNU_IFUNC symbols is postponed till the other
2647 * relocations are done. The indirect functions specified as
2648 * ifunc are allowed to call other symbols, so we need to have
2649 * objects relocated before asking for resolution from indirects.
2651 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2652 * instead of the usual lazy handling of PLT slots. It is
2653 * consistent with how GNU does it.
2656 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2657 RtldLockState *lockstate)
2659 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2661 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2662 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2668 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2669 RtldLockState *lockstate)
2673 for (obj = first; obj != NULL; obj = obj->next) {
2674 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2681 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2682 RtldLockState *lockstate)
2686 STAILQ_FOREACH(elm, list, link) {
2687 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2695 * Cleanup procedure. It will be called (by the atexit mechanism) just
2696 * before the process exits.
2701 RtldLockState lockstate;
2703 wlock_acquire(rtld_bind_lock, &lockstate);
2705 objlist_call_fini(&list_fini, NULL, &lockstate);
2706 /* No need to remove the items from the list, since we are exiting. */
2707 if (!libmap_disable)
2709 lock_release(rtld_bind_lock, &lockstate);
2713 * Iterate over a search path, translate each element, and invoke the
2714 * callback on the result.
2717 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2723 path += strspn(path, ":;");
2724 while (*path != '\0') {
2728 len = strcspn(path, ":;");
2729 trans = lm_findn(NULL, path, len);
2731 res = callback(trans, strlen(trans), arg);
2733 res = callback(path, len, arg);
2739 path += strspn(path, ":;");
2745 struct try_library_args {
2753 try_library_path(const char *dir, size_t dirlen, void *param)
2755 struct try_library_args *arg;
2758 if (*dir == '/' || trust) {
2761 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2764 pathname = arg->buffer;
2765 strncpy(pathname, dir, dirlen);
2766 pathname[dirlen] = '/';
2767 strcpy(pathname + dirlen + 1, arg->name);
2769 dbg(" Trying \"%s\"", pathname);
2770 if (access(pathname, F_OK) == 0) { /* We found it */
2771 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2772 strcpy(pathname, arg->buffer);
2780 search_library_path(const char *name, const char *path)
2783 struct try_library_args arg;
2789 arg.namelen = strlen(name);
2790 arg.buffer = xmalloc(PATH_MAX);
2791 arg.buflen = PATH_MAX;
2793 p = path_enumerate(path, try_library_path, &arg);
2801 dlclose(void *handle)
2804 RtldLockState lockstate;
2806 wlock_acquire(rtld_bind_lock, &lockstate);
2807 root = dlcheck(handle);
2809 lock_release(rtld_bind_lock, &lockstate);
2812 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2815 /* Unreference the object and its dependencies. */
2816 root->dl_refcount--;
2818 if (root->refcount == 1) {
2820 * The object will be no longer referenced, so we must unload it.
2821 * First, call the fini functions.
2823 objlist_call_fini(&list_fini, root, &lockstate);
2827 /* Finish cleaning up the newly-unreferenced objects. */
2828 GDB_STATE(RT_DELETE,&root->linkmap);
2829 unload_object(root);
2830 GDB_STATE(RT_CONSISTENT,NULL);
2834 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2835 lock_release(rtld_bind_lock, &lockstate);
2842 char *msg = error_message;
2843 error_message = NULL;
2848 * This function is deprecated and has no effect.
2851 dllockinit(void *context,
2852 void *(*lock_create)(void *context),
2853 void (*rlock_acquire)(void *lock),
2854 void (*wlock_acquire)(void *lock),
2855 void (*lock_release)(void *lock),
2856 void (*lock_destroy)(void *lock),
2857 void (*context_destroy)(void *context))
2859 static void *cur_context;
2860 static void (*cur_context_destroy)(void *);
2862 /* Just destroy the context from the previous call, if necessary. */
2863 if (cur_context_destroy != NULL)
2864 cur_context_destroy(cur_context);
2865 cur_context = context;
2866 cur_context_destroy = context_destroy;
2870 dlopen(const char *name, int mode)
2873 return (rtld_dlopen(name, -1, mode));
2877 fdlopen(int fd, int mode)
2880 return (rtld_dlopen(NULL, fd, mode));
2884 rtld_dlopen(const char *name, int fd, int mode)
2886 RtldLockState lockstate;
2889 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2890 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2891 if (ld_tracing != NULL) {
2892 rlock_acquire(rtld_bind_lock, &lockstate);
2893 if (sigsetjmp(lockstate.env, 0) != 0)
2894 lock_upgrade(rtld_bind_lock, &lockstate);
2895 environ = (char **)*get_program_var_addr("environ", &lockstate);
2896 lock_release(rtld_bind_lock, &lockstate);
2898 lo_flags = RTLD_LO_DLOPEN;
2899 if (mode & RTLD_NODELETE)
2900 lo_flags |= RTLD_LO_NODELETE;
2901 if (mode & RTLD_NOLOAD)
2902 lo_flags |= RTLD_LO_NOLOAD;
2903 if (ld_tracing != NULL)
2904 lo_flags |= RTLD_LO_TRACE;
2906 return (dlopen_object(name, fd, obj_main, lo_flags,
2907 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2911 dlopen_cleanup(Obj_Entry *obj)
2916 if (obj->refcount == 0)
2921 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2922 int mode, RtldLockState *lockstate)
2924 Obj_Entry **old_obj_tail;
2927 RtldLockState mlockstate;
2930 objlist_init(&initlist);
2932 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2933 wlock_acquire(rtld_bind_lock, &mlockstate);
2934 lockstate = &mlockstate;
2936 GDB_STATE(RT_ADD,NULL);
2938 old_obj_tail = obj_tail;
2940 if (name == NULL && fd == -1) {
2944 obj = load_object(name, fd, refobj, lo_flags);
2949 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2950 objlist_push_tail(&list_global, obj);
2951 if (*old_obj_tail != NULL) { /* We loaded something new. */
2952 assert(*old_obj_tail == obj);
2953 result = load_needed_objects(obj,
2954 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2958 result = rtld_verify_versions(&obj->dagmembers);
2959 if (result != -1 && ld_tracing)
2961 if (result == -1 || relocate_object_dag(obj,
2962 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2963 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2965 dlopen_cleanup(obj);
2967 } else if (lo_flags & RTLD_LO_EARLY) {
2969 * Do not call the init functions for early loaded
2970 * filtees. The image is still not initialized enough
2973 * Our object is found by the global object list and
2974 * will be ordered among all init calls done right
2975 * before transferring control to main.
2978 /* Make list of init functions to call. */
2979 initlist_add_objects(obj, &obj->next, &initlist);
2982 * Process all no_delete or global objects here, given
2983 * them own DAGs to prevent their dependencies from being
2984 * unloaded. This has to be done after we have loaded all
2985 * of the dependencies, so that we do not miss any.
2991 * Bump the reference counts for objects on this DAG. If
2992 * this is the first dlopen() call for the object that was
2993 * already loaded as a dependency, initialize the dag
2999 if ((lo_flags & RTLD_LO_TRACE) != 0)
3002 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3003 obj->z_nodelete) && !obj->ref_nodel) {
3004 dbg("obj %s nodelete", obj->path);
3006 obj->z_nodelete = obj->ref_nodel = true;
3010 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3012 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3014 if (!(lo_flags & RTLD_LO_EARLY)) {
3015 map_stacks_exec(lockstate);
3018 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3019 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3021 objlist_clear(&initlist);
3022 dlopen_cleanup(obj);
3023 if (lockstate == &mlockstate)
3024 lock_release(rtld_bind_lock, lockstate);
3028 if (!(lo_flags & RTLD_LO_EARLY)) {
3029 /* Call the init functions. */
3030 objlist_call_init(&initlist, lockstate);
3032 objlist_clear(&initlist);
3033 if (lockstate == &mlockstate)
3034 lock_release(rtld_bind_lock, lockstate);
3037 trace_loaded_objects(obj);
3038 if (lockstate == &mlockstate)
3039 lock_release(rtld_bind_lock, lockstate);
3044 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3048 const Obj_Entry *obj, *defobj;
3051 RtldLockState lockstate;
3060 symlook_init(&req, name);
3062 req.flags = flags | SYMLOOK_IN_PLT;
3063 req.lockstate = &lockstate;
3065 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3066 rlock_acquire(rtld_bind_lock, &lockstate);
3067 if (sigsetjmp(lockstate.env, 0) != 0)
3068 lock_upgrade(rtld_bind_lock, &lockstate);
3069 if (handle == NULL || handle == RTLD_NEXT ||
3070 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3072 if ((obj = obj_from_addr(retaddr)) == NULL) {
3073 _rtld_error("Cannot determine caller's shared object");
3074 lock_release(rtld_bind_lock, &lockstate);
3075 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
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);
3123 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3127 donelist_init(&donelist);
3128 if (obj->mainprog) {
3129 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3130 res = symlook_global(&req, &donelist);
3133 defobj = req.defobj_out;
3136 * Search the dynamic linker itself, and possibly resolve the
3137 * symbol from there. This is how the application links to
3138 * dynamic linker services such as dlopen.
3140 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3141 res = symlook_obj(&req, &obj_rtld);
3144 defobj = req.defobj_out;
3149 /* Search the whole DAG rooted at the given object. */
3150 res = symlook_list(&req, &obj->dagmembers, &donelist);
3153 defobj = req.defobj_out;
3159 lock_release(rtld_bind_lock, &lockstate);
3162 * The value required by the caller is derived from the value
3163 * of the symbol. For the ia64 architecture, we need to
3164 * construct a function descriptor which the caller can use to
3165 * call the function with the right 'gp' value. For other
3166 * architectures and for non-functions, the value is simply
3167 * the relocated value of the symbol.
3169 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3170 sym = make_function_pointer(def, defobj);
3171 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3172 sym = rtld_resolve_ifunc(defobj, def);
3173 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3175 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3177 ti.ti_module = defobj->tlsindex;
3178 ti.ti_offset = def->st_value;
3179 sym = __tls_get_addr(&ti);
3182 sym = defobj->relocbase + def->st_value;
3183 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3187 _rtld_error("Undefined symbol \"%s\"", name);
3188 lock_release(rtld_bind_lock, &lockstate);
3189 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3194 dlsym(void *handle, const char *name)
3196 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3201 dlfunc(void *handle, const char *name)
3208 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3214 dlvsym(void *handle, const char *name, const char *version)
3218 ventry.name = version;
3220 ventry.hash = elf_hash(version);
3222 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3227 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3229 const Obj_Entry *obj;
3230 RtldLockState lockstate;
3232 rlock_acquire(rtld_bind_lock, &lockstate);
3233 obj = obj_from_addr(addr);
3235 _rtld_error("No shared object contains address");
3236 lock_release(rtld_bind_lock, &lockstate);
3239 rtld_fill_dl_phdr_info(obj, phdr_info);
3240 lock_release(rtld_bind_lock, &lockstate);
3245 dladdr(const void *addr, Dl_info *info)
3247 const Obj_Entry *obj;
3250 unsigned long symoffset;
3251 RtldLockState lockstate;
3253 rlock_acquire(rtld_bind_lock, &lockstate);
3254 obj = obj_from_addr(addr);
3256 _rtld_error("No shared object contains address");
3257 lock_release(rtld_bind_lock, &lockstate);
3260 info->dli_fname = obj->path;
3261 info->dli_fbase = obj->mapbase;
3262 info->dli_saddr = (void *)0;
3263 info->dli_sname = NULL;
3266 * Walk the symbol list looking for the symbol whose address is
3267 * closest to the address sent in.
3269 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3270 def = obj->symtab + symoffset;
3273 * For skip the symbol if st_shndx is either SHN_UNDEF or
3276 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3280 * If the symbol is greater than the specified address, or if it
3281 * is further away from addr than the current nearest symbol,
3284 symbol_addr = obj->relocbase + def->st_value;
3285 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3288 /* Update our idea of the nearest symbol. */
3289 info->dli_sname = obj->strtab + def->st_name;
3290 info->dli_saddr = symbol_addr;
3293 if (info->dli_saddr == addr)
3296 lock_release(rtld_bind_lock, &lockstate);
3301 dlinfo(void *handle, int request, void *p)
3303 const Obj_Entry *obj;
3304 RtldLockState lockstate;
3307 rlock_acquire(rtld_bind_lock, &lockstate);
3309 if (handle == NULL || handle == RTLD_SELF) {
3312 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3313 if ((obj = obj_from_addr(retaddr)) == NULL)
3314 _rtld_error("Cannot determine caller's shared object");
3316 obj = dlcheck(handle);
3319 lock_release(rtld_bind_lock, &lockstate);
3325 case RTLD_DI_LINKMAP:
3326 *((struct link_map const **)p) = &obj->linkmap;
3328 case RTLD_DI_ORIGIN:
3329 error = rtld_dirname(obj->path, p);
3332 case RTLD_DI_SERINFOSIZE:
3333 case RTLD_DI_SERINFO:
3334 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3338 _rtld_error("Invalid request %d passed to dlinfo()", request);
3342 lock_release(rtld_bind_lock, &lockstate);
3348 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3351 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3352 phdr_info->dlpi_name = obj->path;
3353 phdr_info->dlpi_phdr = obj->phdr;
3354 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3355 phdr_info->dlpi_tls_modid = obj->tlsindex;
3356 phdr_info->dlpi_tls_data = obj->tlsinit;
3357 phdr_info->dlpi_adds = obj_loads;
3358 phdr_info->dlpi_subs = obj_loads - obj_count;
3362 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3364 struct dl_phdr_info phdr_info;
3365 const Obj_Entry *obj;
3366 RtldLockState bind_lockstate, phdr_lockstate;
3369 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3370 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3374 for (obj = obj_list; obj != NULL; obj = obj->next) {
3375 rtld_fill_dl_phdr_info(obj, &phdr_info);
3376 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3380 lock_release(rtld_bind_lock, &bind_lockstate);
3381 lock_release(rtld_phdr_lock, &phdr_lockstate);
3387 fill_search_info(const char *dir, size_t dirlen, void *param)
3389 struct fill_search_info_args *arg;
3393 if (arg->request == RTLD_DI_SERINFOSIZE) {
3394 arg->serinfo->dls_cnt ++;
3395 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3397 struct dl_serpath *s_entry;
3399 s_entry = arg->serpath;
3400 s_entry->dls_name = arg->strspace;
3401 s_entry->dls_flags = arg->flags;
3403 strncpy(arg->strspace, dir, dirlen);
3404 arg->strspace[dirlen] = '\0';
3406 arg->strspace += dirlen + 1;
3414 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3416 struct dl_serinfo _info;
3417 struct fill_search_info_args args;
3419 args.request = RTLD_DI_SERINFOSIZE;
3420 args.serinfo = &_info;
3422 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3425 path_enumerate(obj->rpath, fill_search_info, &args);
3426 path_enumerate(ld_library_path, fill_search_info, &args);
3427 path_enumerate(obj->runpath, fill_search_info, &args);
3428 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3429 if (!obj->z_nodeflib)
3430 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3433 if (request == RTLD_DI_SERINFOSIZE) {
3434 info->dls_size = _info.dls_size;
3435 info->dls_cnt = _info.dls_cnt;
3439 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3440 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3444 args.request = RTLD_DI_SERINFO;
3445 args.serinfo = info;
3446 args.serpath = &info->dls_serpath[0];
3447 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3449 args.flags = LA_SER_RUNPATH;
3450 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3453 args.flags = LA_SER_LIBPATH;
3454 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3457 args.flags = LA_SER_RUNPATH;
3458 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3461 args.flags = LA_SER_CONFIG;
3462 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3466 args.flags = LA_SER_DEFAULT;
3467 if (!obj->z_nodeflib &&
3468 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3474 rtld_dirname(const char *path, char *bname)
3478 /* Empty or NULL string gets treated as "." */
3479 if (path == NULL || *path == '\0') {
3485 /* Strip trailing slashes */
3486 endp = path + strlen(path) - 1;
3487 while (endp > path && *endp == '/')
3490 /* Find the start of the dir */
3491 while (endp > path && *endp != '/')
3494 /* Either the dir is "/" or there are no slashes */
3496 bname[0] = *endp == '/' ? '/' : '.';
3502 } while (endp > path && *endp == '/');
3505 if (endp - path + 2 > PATH_MAX)
3507 _rtld_error("Filename is too long: %s", path);
3511 strncpy(bname, path, endp - path + 1);
3512 bname[endp - path + 1] = '\0';
3517 rtld_dirname_abs(const char *path, char *base)
3521 if (realpath(path, base) == NULL)
3523 dbg("%s -> %s", path, base);
3524 last = strrchr(base, '/');
3533 linkmap_add(Obj_Entry *obj)
3535 struct link_map *l = &obj->linkmap;
3536 struct link_map *prev;
3538 obj->linkmap.l_name = obj->path;
3539 obj->linkmap.l_addr = obj->mapbase;
3540 obj->linkmap.l_ld = obj->dynamic;
3542 /* GDB needs load offset on MIPS to use the symbols */
3543 obj->linkmap.l_offs = obj->relocbase;
3546 if (r_debug.r_map == NULL) {
3552 * Scan to the end of the list, but not past the entry for the
3553 * dynamic linker, which we want to keep at the very end.
3555 for (prev = r_debug.r_map;
3556 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3557 prev = prev->l_next)
3560 /* Link in the new entry. */
3562 l->l_next = prev->l_next;
3563 if (l->l_next != NULL)
3564 l->l_next->l_prev = l;
3569 linkmap_delete(Obj_Entry *obj)
3571 struct link_map *l = &obj->linkmap;
3573 if (l->l_prev == NULL) {
3574 if ((r_debug.r_map = l->l_next) != NULL)
3575 l->l_next->l_prev = NULL;
3579 if ((l->l_prev->l_next = l->l_next) != NULL)
3580 l->l_next->l_prev = l->l_prev;
3584 * Function for the debugger to set a breakpoint on to gain control.
3586 * The two parameters allow the debugger to easily find and determine
3587 * what the runtime loader is doing and to whom it is doing it.
3589 * When the loadhook trap is hit (r_debug_state, set at program
3590 * initialization), the arguments can be found on the stack:
3592 * +8 struct link_map *m
3593 * +4 struct r_debug *rd
3597 r_debug_state(struct r_debug* rd, struct link_map *m)
3600 * The following is a hack to force the compiler to emit calls to
3601 * this function, even when optimizing. If the function is empty,
3602 * the compiler is not obliged to emit any code for calls to it,
3603 * even when marked __noinline. However, gdb depends on those
3606 __compiler_membar();
3610 * A function called after init routines have completed. This can be used to
3611 * break before a program's entry routine is called, and can be used when
3612 * main is not available in the symbol table.
3615 _r_debug_postinit(struct link_map *m)
3618 /* See r_debug_state(). */
3619 __compiler_membar();
3623 * Get address of the pointer variable in the main program.
3624 * Prefer non-weak symbol over the weak one.
3626 static const void **
3627 get_program_var_addr(const char *name, RtldLockState *lockstate)
3632 symlook_init(&req, name);
3633 req.lockstate = lockstate;
3634 donelist_init(&donelist);
3635 if (symlook_global(&req, &donelist) != 0)
3637 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3638 return ((const void **)make_function_pointer(req.sym_out,
3640 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3641 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3643 return ((const void **)(req.defobj_out->relocbase +
3644 req.sym_out->st_value));
3648 * Set a pointer variable in the main program to the given value. This
3649 * is used to set key variables such as "environ" before any of the
3650 * init functions are called.
3653 set_program_var(const char *name, const void *value)
3657 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3658 dbg("\"%s\": *%p <-- %p", name, addr, value);
3664 * Search the global objects, including dependencies and main object,
3665 * for the given symbol.
3668 symlook_global(SymLook *req, DoneList *donelist)
3671 const Objlist_Entry *elm;
3674 symlook_init_from_req(&req1, req);
3676 /* Search all objects loaded at program start up. */
3677 if (req->defobj_out == NULL ||
3678 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3679 res = symlook_list(&req1, &list_main, donelist);
3680 if (res == 0 && (req->defobj_out == NULL ||
3681 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3682 req->sym_out = req1.sym_out;
3683 req->defobj_out = req1.defobj_out;
3684 assert(req->defobj_out != NULL);
3688 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3689 STAILQ_FOREACH(elm, &list_global, link) {
3690 if (req->defobj_out != NULL &&
3691 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3693 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3694 if (res == 0 && (req->defobj_out == NULL ||
3695 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3696 req->sym_out = req1.sym_out;
3697 req->defobj_out = req1.defobj_out;
3698 assert(req->defobj_out != NULL);
3702 return (req->sym_out != NULL ? 0 : ESRCH);
3706 * Given a symbol name in a referencing object, find the corresponding
3707 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3708 * no definition was found. Returns a pointer to the Obj_Entry of the
3709 * defining object via the reference parameter DEFOBJ_OUT.
3712 symlook_default(SymLook *req, const Obj_Entry *refobj)
3715 const Objlist_Entry *elm;
3719 donelist_init(&donelist);
3720 symlook_init_from_req(&req1, req);
3722 /* Look first in the referencing object if linked symbolically. */
3723 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3724 res = symlook_obj(&req1, refobj);
3726 req->sym_out = req1.sym_out;
3727 req->defobj_out = req1.defobj_out;
3728 assert(req->defobj_out != NULL);
3732 symlook_global(req, &donelist);
3734 /* Search all dlopened DAGs containing the referencing object. */
3735 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3736 if (req->sym_out != NULL &&
3737 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3739 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3740 if (res == 0 && (req->sym_out == NULL ||
3741 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3742 req->sym_out = req1.sym_out;
3743 req->defobj_out = req1.defobj_out;
3744 assert(req->defobj_out != NULL);
3749 * Search the dynamic linker itself, and possibly resolve the
3750 * symbol from there. This is how the application links to
3751 * dynamic linker services such as dlopen.
3753 if (req->sym_out == NULL ||
3754 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3755 res = symlook_obj(&req1, &obj_rtld);
3757 req->sym_out = req1.sym_out;
3758 req->defobj_out = req1.defobj_out;
3759 assert(req->defobj_out != NULL);
3763 return (req->sym_out != NULL ? 0 : ESRCH);
3767 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3770 const Obj_Entry *defobj;
3771 const Objlist_Entry *elm;
3777 STAILQ_FOREACH(elm, objlist, link) {
3778 if (donelist_check(dlp, elm->obj))
3780 symlook_init_from_req(&req1, req);
3781 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3782 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3784 defobj = req1.defobj_out;
3785 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3792 req->defobj_out = defobj;
3799 * Search the chain of DAGS cointed to by the given Needed_Entry
3800 * for a symbol of the given name. Each DAG is scanned completely
3801 * before advancing to the next one. Returns a pointer to the symbol,
3802 * or NULL if no definition was found.
3805 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3808 const Needed_Entry *n;
3809 const Obj_Entry *defobj;
3815 symlook_init_from_req(&req1, req);
3816 for (n = needed; n != NULL; n = n->next) {
3817 if (n->obj == NULL ||
3818 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3820 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3822 defobj = req1.defobj_out;
3823 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3829 req->defobj_out = defobj;
3836 * Search the symbol table of a single shared object for a symbol of
3837 * the given name and version, if requested. Returns a pointer to the
3838 * symbol, or NULL if no definition was found. If the object is
3839 * filter, return filtered symbol from filtee.
3841 * The symbol's hash value is passed in for efficiency reasons; that
3842 * eliminates many recomputations of the hash value.
3845 symlook_obj(SymLook *req, const Obj_Entry *obj)
3849 int flags, res, mres;
3852 * If there is at least one valid hash at this point, we prefer to
3853 * use the faster GNU version if available.
3855 if (obj->valid_hash_gnu)
3856 mres = symlook_obj1_gnu(req, obj);
3857 else if (obj->valid_hash_sysv)
3858 mres = symlook_obj1_sysv(req, obj);
3863 if (obj->needed_filtees != NULL) {
3864 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3865 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3866 donelist_init(&donelist);
3867 symlook_init_from_req(&req1, req);
3868 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3870 req->sym_out = req1.sym_out;
3871 req->defobj_out = req1.defobj_out;
3875 if (obj->needed_aux_filtees != NULL) {
3876 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3877 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3878 donelist_init(&donelist);
3879 symlook_init_from_req(&req1, req);
3880 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3882 req->sym_out = req1.sym_out;
3883 req->defobj_out = req1.defobj_out;
3891 /* Symbol match routine common to both hash functions */
3893 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3894 const unsigned long symnum)
3897 const Elf_Sym *symp;
3900 symp = obj->symtab + symnum;
3901 strp = obj->strtab + symp->st_name;
3903 switch (ELF_ST_TYPE(symp->st_info)) {
3909 if (symp->st_value == 0)
3913 if (symp->st_shndx != SHN_UNDEF)
3916 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3917 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3924 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3927 if (req->ventry == NULL) {
3928 if (obj->versyms != NULL) {
3929 verndx = VER_NDX(obj->versyms[symnum]);
3930 if (verndx > obj->vernum) {
3932 "%s: symbol %s references wrong version %d",
3933 obj->path, obj->strtab + symnum, verndx);
3937 * If we are not called from dlsym (i.e. this
3938 * is a normal relocation from unversioned
3939 * binary), accept the symbol immediately if
3940 * it happens to have first version after this
3941 * shared object became versioned. Otherwise,
3942 * if symbol is versioned and not hidden,
3943 * remember it. If it is the only symbol with
3944 * this name exported by the shared object, it
3945 * will be returned as a match by the calling
3946 * function. If symbol is global (verndx < 2)
3947 * accept it unconditionally.
3949 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3950 verndx == VER_NDX_GIVEN) {
3951 result->sym_out = symp;
3954 else if (verndx >= VER_NDX_GIVEN) {
3955 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3957 if (result->vsymp == NULL)
3958 result->vsymp = symp;
3964 result->sym_out = symp;
3967 if (obj->versyms == NULL) {
3968 if (object_match_name(obj, req->ventry->name)) {
3969 _rtld_error("%s: object %s should provide version %s "
3970 "for symbol %s", obj_rtld.path, obj->path,
3971 req->ventry->name, obj->strtab + symnum);
3975 verndx = VER_NDX(obj->versyms[symnum]);
3976 if (verndx > obj->vernum) {
3977 _rtld_error("%s: symbol %s references wrong version %d",
3978 obj->path, obj->strtab + symnum, verndx);
3981 if (obj->vertab[verndx].hash != req->ventry->hash ||
3982 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3984 * Version does not match. Look if this is a
3985 * global symbol and if it is not hidden. If
3986 * global symbol (verndx < 2) is available,
3987 * use it. Do not return symbol if we are
3988 * called by dlvsym, because dlvsym looks for
3989 * a specific version and default one is not
3990 * what dlvsym wants.
3992 if ((req->flags & SYMLOOK_DLSYM) ||
3993 (verndx >= VER_NDX_GIVEN) ||
3994 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3998 result->sym_out = symp;
4003 * Search for symbol using SysV hash function.
4004 * obj->buckets is known not to be NULL at this point; the test for this was
4005 * performed with the obj->valid_hash_sysv assignment.
4008 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4010 unsigned long symnum;
4011 Sym_Match_Result matchres;
4013 matchres.sym_out = NULL;
4014 matchres.vsymp = NULL;
4015 matchres.vcount = 0;
4017 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4018 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4019 if (symnum >= obj->nchains)
4020 return (ESRCH); /* Bad object */
4022 if (matched_symbol(req, obj, &matchres, symnum)) {
4023 req->sym_out = matchres.sym_out;
4024 req->defobj_out = obj;
4028 if (matchres.vcount == 1) {
4029 req->sym_out = matchres.vsymp;
4030 req->defobj_out = obj;
4036 /* Search for symbol using GNU hash function */
4038 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4040 Elf_Addr bloom_word;
4041 const Elf32_Word *hashval;
4043 Sym_Match_Result matchres;
4044 unsigned int h1, h2;
4045 unsigned long symnum;
4047 matchres.sym_out = NULL;
4048 matchres.vsymp = NULL;
4049 matchres.vcount = 0;
4051 /* Pick right bitmask word from Bloom filter array */
4052 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4053 obj->maskwords_bm_gnu];
4055 /* Calculate modulus word size of gnu hash and its derivative */
4056 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4057 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4059 /* Filter out the "definitely not in set" queries */
4060 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4063 /* Locate hash chain and corresponding value element*/
4064 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4067 hashval = &obj->chain_zero_gnu[bucket];
4069 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4070 symnum = hashval - obj->chain_zero_gnu;
4071 if (matched_symbol(req, obj, &matchres, symnum)) {
4072 req->sym_out = matchres.sym_out;
4073 req->defobj_out = obj;
4077 } while ((*hashval++ & 1) == 0);
4078 if (matchres.vcount == 1) {
4079 req->sym_out = matchres.vsymp;
4080 req->defobj_out = obj;
4087 trace_loaded_objects(Obj_Entry *obj)
4089 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4092 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4095 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4096 fmt1 = "\t%o => %p (%x)\n";
4098 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4099 fmt2 = "\t%o (%x)\n";
4101 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4103 for (; obj; obj = obj->next) {
4104 Needed_Entry *needed;
4108 if (list_containers && obj->needed != NULL)
4109 rtld_printf("%s:\n", obj->path);
4110 for (needed = obj->needed; needed; needed = needed->next) {
4111 if (needed->obj != NULL) {
4112 if (needed->obj->traced && !list_containers)
4114 needed->obj->traced = true;
4115 path = needed->obj->path;
4119 name = (char *)obj->strtab + needed->name;
4120 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4122 fmt = is_lib ? fmt1 : fmt2;
4123 while ((c = *fmt++) != '\0') {
4149 rtld_putstr(main_local);
4152 rtld_putstr(obj_main->path);
4159 rtld_printf("%d", sodp->sod_major);
4162 rtld_printf("%d", sodp->sod_minor);
4169 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4182 * Unload a dlopened object and its dependencies from memory and from
4183 * our data structures. It is assumed that the DAG rooted in the
4184 * object has already been unreferenced, and that the object has a
4185 * reference count of 0.
4188 unload_object(Obj_Entry *root)
4193 assert(root->refcount == 0);
4196 * Pass over the DAG removing unreferenced objects from
4197 * appropriate lists.
4199 unlink_object(root);
4201 /* Unmap all objects that are no longer referenced. */
4202 linkp = &obj_list->next;
4203 while ((obj = *linkp) != NULL) {
4204 if (obj->refcount == 0) {
4205 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4207 dbg("unloading \"%s\"", obj->path);
4208 unload_filtees(root);
4209 munmap(obj->mapbase, obj->mapsize);
4210 linkmap_delete(obj);
4221 unlink_object(Obj_Entry *root)
4225 if (root->refcount == 0) {
4226 /* Remove the object from the RTLD_GLOBAL list. */
4227 objlist_remove(&list_global, root);
4229 /* Remove the object from all objects' DAG lists. */
4230 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4231 objlist_remove(&elm->obj->dldags, root);
4232 if (elm->obj != root)
4233 unlink_object(elm->obj);
4239 ref_dag(Obj_Entry *root)
4243 assert(root->dag_inited);
4244 STAILQ_FOREACH(elm, &root->dagmembers, link)
4245 elm->obj->refcount++;
4249 unref_dag(Obj_Entry *root)
4253 assert(root->dag_inited);
4254 STAILQ_FOREACH(elm, &root->dagmembers, link)
4255 elm->obj->refcount--;
4259 * Common code for MD __tls_get_addr().
4261 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4263 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4265 Elf_Addr *newdtv, *dtv;
4266 RtldLockState lockstate;
4270 /* Check dtv generation in case new modules have arrived */
4271 if (dtv[0] != tls_dtv_generation) {
4272 wlock_acquire(rtld_bind_lock, &lockstate);
4273 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4275 if (to_copy > tls_max_index)
4276 to_copy = tls_max_index;
4277 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4278 newdtv[0] = tls_dtv_generation;
4279 newdtv[1] = tls_max_index;
4281 lock_release(rtld_bind_lock, &lockstate);
4282 dtv = *dtvp = newdtv;
4285 /* Dynamically allocate module TLS if necessary */
4286 if (dtv[index + 1] == 0) {
4287 /* Signal safe, wlock will block out signals. */
4288 wlock_acquire(rtld_bind_lock, &lockstate);
4289 if (!dtv[index + 1])
4290 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4291 lock_release(rtld_bind_lock, &lockstate);
4293 return ((void *)(dtv[index + 1] + offset));
4297 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4302 /* Check dtv generation in case new modules have arrived */
4303 if (__predict_true(dtv[0] == tls_dtv_generation &&
4304 dtv[index + 1] != 0))
4305 return ((void *)(dtv[index + 1] + offset));
4306 return (tls_get_addr_slow(dtvp, index, offset));
4309 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__)
4312 * Allocate Static TLS using the Variant I method.
4315 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4324 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4327 assert(tcbsize >= TLS_TCB_SIZE);
4328 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4329 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4331 if (oldtcb != NULL) {
4332 memcpy(tls, oldtcb, tls_static_space);
4335 /* Adjust the DTV. */
4337 for (i = 0; i < dtv[1]; i++) {
4338 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4339 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4340 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4344 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4346 dtv[0] = tls_dtv_generation;
4347 dtv[1] = tls_max_index;
4349 for (obj = objs; obj; obj = obj->next) {
4350 if (obj->tlsoffset > 0) {
4351 addr = (Elf_Addr)tls + obj->tlsoffset;
4352 if (obj->tlsinitsize > 0)
4353 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4354 if (obj->tlssize > obj->tlsinitsize)
4355 memset((void*) (addr + obj->tlsinitsize), 0,
4356 obj->tlssize - obj->tlsinitsize);
4357 dtv[obj->tlsindex + 1] = addr;
4366 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4369 Elf_Addr tlsstart, tlsend;
4372 assert(tcbsize >= TLS_TCB_SIZE);
4374 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4375 tlsend = tlsstart + tls_static_space;
4377 dtv = *(Elf_Addr **)tlsstart;
4379 for (i = 0; i < dtvsize; i++) {
4380 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4381 free((void*)dtv[i+2]);
4390 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4393 * Allocate Static TLS using the Variant II method.
4396 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4399 size_t size, ralign;
4401 Elf_Addr *dtv, *olddtv;
4402 Elf_Addr segbase, oldsegbase, addr;
4406 if (tls_static_max_align > ralign)
4407 ralign = tls_static_max_align;
4408 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4410 assert(tcbsize >= 2*sizeof(Elf_Addr));
4411 tls = malloc_aligned(size, ralign);
4412 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4414 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4415 ((Elf_Addr*)segbase)[0] = segbase;
4416 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4418 dtv[0] = tls_dtv_generation;
4419 dtv[1] = tls_max_index;
4423 * Copy the static TLS block over whole.
4425 oldsegbase = (Elf_Addr) oldtls;
4426 memcpy((void *)(segbase - tls_static_space),
4427 (const void *)(oldsegbase - tls_static_space),
4431 * If any dynamic TLS blocks have been created tls_get_addr(),
4434 olddtv = ((Elf_Addr**)oldsegbase)[1];
4435 for (i = 0; i < olddtv[1]; i++) {
4436 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4437 dtv[i+2] = olddtv[i+2];
4443 * We assume that this block was the one we created with
4444 * allocate_initial_tls().
4446 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4448 for (obj = objs; obj; obj = obj->next) {
4449 if (obj->tlsoffset) {
4450 addr = segbase - obj->tlsoffset;
4451 memset((void*) (addr + obj->tlsinitsize),
4452 0, obj->tlssize - obj->tlsinitsize);
4454 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4455 dtv[obj->tlsindex + 1] = addr;
4460 return (void*) segbase;
4464 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4467 size_t size, ralign;
4469 Elf_Addr tlsstart, tlsend;
4472 * Figure out the size of the initial TLS block so that we can
4473 * find stuff which ___tls_get_addr() allocated dynamically.
4476 if (tls_static_max_align > ralign)
4477 ralign = tls_static_max_align;
4478 size = round(tls_static_space, ralign);
4480 dtv = ((Elf_Addr**)tls)[1];
4482 tlsend = (Elf_Addr) tls;
4483 tlsstart = tlsend - size;
4484 for (i = 0; i < dtvsize; i++) {
4485 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4486 free_aligned((void *)dtv[i + 2]);
4490 free_aligned((void *)tlsstart);
4497 * Allocate TLS block for module with given index.
4500 allocate_module_tls(int index)
4505 for (obj = obj_list; obj; obj = obj->next) {
4506 if (obj->tlsindex == index)
4510 _rtld_error("Can't find module with TLS index %d", index);
4514 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4515 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4516 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4522 allocate_tls_offset(Obj_Entry *obj)
4529 if (obj->tlssize == 0) {
4530 obj->tls_done = true;
4534 if (tls_last_offset == 0)
4535 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4537 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4538 obj->tlssize, obj->tlsalign);
4541 * If we have already fixed the size of the static TLS block, we
4542 * must stay within that size. When allocating the static TLS, we
4543 * leave a small amount of space spare to be used for dynamically
4544 * loading modules which use static TLS.
4546 if (tls_static_space != 0) {
4547 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4549 } else if (obj->tlsalign > tls_static_max_align) {
4550 tls_static_max_align = obj->tlsalign;
4553 tls_last_offset = obj->tlsoffset = off;
4554 tls_last_size = obj->tlssize;
4555 obj->tls_done = true;
4561 free_tls_offset(Obj_Entry *obj)
4565 * If we were the last thing to allocate out of the static TLS
4566 * block, we give our space back to the 'allocator'. This is a
4567 * simplistic workaround to allow libGL.so.1 to be loaded and
4568 * unloaded multiple times.
4570 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4571 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4572 tls_last_offset -= obj->tlssize;
4578 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4581 RtldLockState lockstate;
4583 wlock_acquire(rtld_bind_lock, &lockstate);
4584 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4585 lock_release(rtld_bind_lock, &lockstate);
4590 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4592 RtldLockState lockstate;
4594 wlock_acquire(rtld_bind_lock, &lockstate);
4595 free_tls(tcb, tcbsize, tcbalign);
4596 lock_release(rtld_bind_lock, &lockstate);
4600 object_add_name(Obj_Entry *obj, const char *name)
4606 entry = malloc(sizeof(Name_Entry) + len);
4608 if (entry != NULL) {
4609 strcpy(entry->name, name);
4610 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4615 object_match_name(const Obj_Entry *obj, const char *name)
4619 STAILQ_FOREACH(entry, &obj->names, link) {
4620 if (strcmp(name, entry->name) == 0)
4627 locate_dependency(const Obj_Entry *obj, const char *name)
4629 const Objlist_Entry *entry;
4630 const Needed_Entry *needed;
4632 STAILQ_FOREACH(entry, &list_main, link) {
4633 if (object_match_name(entry->obj, name))
4637 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4638 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4639 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4641 * If there is DT_NEEDED for the name we are looking for,
4642 * we are all set. Note that object might not be found if
4643 * dependency was not loaded yet, so the function can
4644 * return NULL here. This is expected and handled
4645 * properly by the caller.
4647 return (needed->obj);
4650 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4656 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4657 const Elf_Vernaux *vna)
4659 const Elf_Verdef *vd;
4660 const char *vername;
4662 vername = refobj->strtab + vna->vna_name;
4663 vd = depobj->verdef;
4665 _rtld_error("%s: version %s required by %s not defined",
4666 depobj->path, vername, refobj->path);
4670 if (vd->vd_version != VER_DEF_CURRENT) {
4671 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4672 depobj->path, vd->vd_version);
4675 if (vna->vna_hash == vd->vd_hash) {
4676 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4677 ((char *)vd + vd->vd_aux);
4678 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4681 if (vd->vd_next == 0)
4683 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4685 if (vna->vna_flags & VER_FLG_WEAK)
4687 _rtld_error("%s: version %s required by %s not found",
4688 depobj->path, vername, refobj->path);
4693 rtld_verify_object_versions(Obj_Entry *obj)
4695 const Elf_Verneed *vn;
4696 const Elf_Verdef *vd;
4697 const Elf_Verdaux *vda;
4698 const Elf_Vernaux *vna;
4699 const Obj_Entry *depobj;
4700 int maxvernum, vernum;
4702 if (obj->ver_checked)
4704 obj->ver_checked = true;
4708 * Walk over defined and required version records and figure out
4709 * max index used by any of them. Do very basic sanity checking
4713 while (vn != NULL) {
4714 if (vn->vn_version != VER_NEED_CURRENT) {
4715 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4716 obj->path, vn->vn_version);
4719 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4721 vernum = VER_NEED_IDX(vna->vna_other);
4722 if (vernum > maxvernum)
4724 if (vna->vna_next == 0)
4726 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4728 if (vn->vn_next == 0)
4730 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4734 while (vd != NULL) {
4735 if (vd->vd_version != VER_DEF_CURRENT) {
4736 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4737 obj->path, vd->vd_version);
4740 vernum = VER_DEF_IDX(vd->vd_ndx);
4741 if (vernum > maxvernum)
4743 if (vd->vd_next == 0)
4745 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4752 * Store version information in array indexable by version index.
4753 * Verify that object version requirements are satisfied along the
4756 obj->vernum = maxvernum + 1;
4757 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4760 while (vd != NULL) {
4761 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4762 vernum = VER_DEF_IDX(vd->vd_ndx);
4763 assert(vernum <= maxvernum);
4764 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4765 obj->vertab[vernum].hash = vd->vd_hash;
4766 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4767 obj->vertab[vernum].file = NULL;
4768 obj->vertab[vernum].flags = 0;
4770 if (vd->vd_next == 0)
4772 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4776 while (vn != NULL) {
4777 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4780 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4782 if (check_object_provided_version(obj, depobj, vna))
4784 vernum = VER_NEED_IDX(vna->vna_other);
4785 assert(vernum <= maxvernum);
4786 obj->vertab[vernum].hash = vna->vna_hash;
4787 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4788 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4789 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4790 VER_INFO_HIDDEN : 0;
4791 if (vna->vna_next == 0)
4793 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4795 if (vn->vn_next == 0)
4797 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4803 rtld_verify_versions(const Objlist *objlist)
4805 Objlist_Entry *entry;
4809 STAILQ_FOREACH(entry, objlist, link) {
4811 * Skip dummy objects or objects that have their version requirements
4814 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4816 if (rtld_verify_object_versions(entry->obj) == -1) {
4818 if (ld_tracing == NULL)
4822 if (rc == 0 || ld_tracing != NULL)
4823 rc = rtld_verify_object_versions(&obj_rtld);
4828 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4833 vernum = VER_NDX(obj->versyms[symnum]);
4834 if (vernum >= obj->vernum) {
4835 _rtld_error("%s: symbol %s has wrong verneed value %d",
4836 obj->path, obj->strtab + symnum, vernum);
4837 } else if (obj->vertab[vernum].hash != 0) {
4838 return &obj->vertab[vernum];
4845 _rtld_get_stack_prot(void)
4848 return (stack_prot);
4852 _rtld_is_dlopened(void *arg)
4855 RtldLockState lockstate;
4858 rlock_acquire(rtld_bind_lock, &lockstate);
4861 obj = obj_from_addr(arg);
4863 _rtld_error("No shared object contains address");
4864 lock_release(rtld_bind_lock, &lockstate);
4867 res = obj->dlopened ? 1 : 0;
4868 lock_release(rtld_bind_lock, &lockstate);
4873 map_stacks_exec(RtldLockState *lockstate)
4875 void (*thr_map_stacks_exec)(void);
4877 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4879 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4880 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4881 if (thr_map_stacks_exec != NULL) {
4882 stack_prot |= PROT_EXEC;
4883 thr_map_stacks_exec();
4888 symlook_init(SymLook *dst, const char *name)
4891 bzero(dst, sizeof(*dst));
4893 dst->hash = elf_hash(name);
4894 dst->hash_gnu = gnu_hash(name);
4898 symlook_init_from_req(SymLook *dst, const SymLook *src)
4901 dst->name = src->name;
4902 dst->hash = src->hash;
4903 dst->hash_gnu = src->hash_gnu;
4904 dst->ventry = src->ventry;
4905 dst->flags = src->flags;
4906 dst->defobj_out = NULL;
4907 dst->sym_out = NULL;
4908 dst->lockstate = src->lockstate;
4912 * Overrides for libc_pic-provided functions.
4916 __getosreldate(void)
4926 oid[1] = KERN_OSRELDATE;
4928 len = sizeof(osrel);
4929 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4930 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4942 void (*__cleanup)(void);
4943 int __isthreaded = 0;
4944 int _thread_autoinit_dummy_decl = 1;
4947 * No unresolved symbols for rtld.
4950 __pthread_cxa_finalize(struct dl_phdr_info *a)
4955 __stack_chk_fail(void)
4958 _rtld_error("stack overflow detected; terminated");
4961 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
4967 _rtld_error("buffer overflow detected; terminated");
4972 rtld_strerror(int errnum)
4975 if (errnum < 0 || errnum >= sys_nerr)
4976 return ("Unknown error");
4977 return (sys_errlist[errnum]);