2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
38 #error "GCC is needed to compile this file"
41 #include <sys/param.h>
42 #include <sys/mount.h>
45 #include <sys/sysctl.h>
47 #include <sys/utsname.h>
48 #include <sys/ktrace.h>
64 #include "rtld_printf.h"
68 #define PATH_RTLD "/libexec/ld-elf.so.1"
70 #define PATH_RTLD "/libexec/ld-elf32.so.1"
74 typedef void (*func_ptr_type)();
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 * Function declarations.
80 static const char *basename(const char *);
81 static void die(void) __dead2;
82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
83 const Elf_Dyn **, const Elf_Dyn **);
84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
86 static void digest_dynamic(Obj_Entry *, int);
87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
88 static Obj_Entry *dlcheck(void *);
89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
90 int lo_flags, int mode, RtldLockState *lockstate);
91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
93 static bool donelist_check(DoneList *, const Obj_Entry *);
94 static void errmsg_restore(char *);
95 static char *errmsg_save(void);
96 static void *fill_search_info(const char *, size_t, void *);
97 static char *find_library(const char *, const Obj_Entry *);
98 static const char *gethints(bool);
99 static void init_dag(Obj_Entry *);
100 static void init_pagesizes(Elf_Auxinfo **aux_info);
101 static void init_rtld(caddr_t, Elf_Auxinfo **);
102 static void initlist_add_neededs(Needed_Entry *, Objlist *);
103 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
104 static void linkmap_add(Obj_Entry *);
105 static void linkmap_delete(Obj_Entry *);
106 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
107 static void unload_filtees(Obj_Entry *);
108 static int load_needed_objects(Obj_Entry *, int);
109 static int load_preload_objects(void);
110 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
111 static void map_stacks_exec(RtldLockState *);
112 static Obj_Entry *obj_from_addr(const void *);
113 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
114 static void objlist_call_init(Objlist *, RtldLockState *);
115 static void objlist_clear(Objlist *);
116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
117 static void objlist_init(Objlist *);
118 static void objlist_push_head(Objlist *, Obj_Entry *);
119 static void objlist_push_tail(Objlist *, Obj_Entry *);
120 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
121 static void objlist_remove(Objlist *, Obj_Entry *);
122 static void *path_enumerate(const char *, path_enum_proc, void *);
123 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
124 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
125 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
126 int flags, RtldLockState *lockstate);
127 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
129 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
130 int flags, RtldLockState *lockstate);
131 static int rtld_dirname(const char *, char *);
132 static int rtld_dirname_abs(const char *, char *);
133 static void *rtld_dlopen(const char *name, int fd, int mode);
134 static void rtld_exit(void);
135 static char *search_library_path(const char *, const char *);
136 static const void **get_program_var_addr(const char *, RtldLockState *);
137 static void set_program_var(const char *, const void *);
138 static int symlook_default(SymLook *, const Obj_Entry *refobj);
139 static int symlook_global(SymLook *, DoneList *);
140 static void symlook_init_from_req(SymLook *, const SymLook *);
141 static int symlook_list(SymLook *, const Objlist *, DoneList *);
142 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
143 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
144 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
145 static void trace_loaded_objects(Obj_Entry *);
146 static void unlink_object(Obj_Entry *);
147 static void unload_object(Obj_Entry *);
148 static void unref_dag(Obj_Entry *);
149 static void ref_dag(Obj_Entry *);
150 static char *origin_subst_one(char *, const char *, const char *, bool);
151 static char *origin_subst(char *, const char *);
152 static void preinit_main(void);
153 static int rtld_verify_versions(const Objlist *);
154 static int rtld_verify_object_versions(Obj_Entry *);
155 static void object_add_name(Obj_Entry *, const char *);
156 static int object_match_name(const Obj_Entry *, const char *);
157 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
158 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
159 struct dl_phdr_info *phdr_info);
160 static uint32_t gnu_hash(const char *);
161 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
162 const unsigned long);
164 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
165 void _r_debug_postinit(struct link_map *) __noinline;
170 static char *error_message; /* Message for dlerror(), or NULL */
171 struct r_debug r_debug; /* for GDB; */
172 static bool libmap_disable; /* Disable libmap */
173 static bool ld_loadfltr; /* Immediate filters processing */
174 static char *libmap_override; /* Maps to use in addition to libmap.conf */
175 static bool trust; /* False for setuid and setgid programs */
176 static bool dangerous_ld_env; /* True if environment variables have been
177 used to affect the libraries loaded */
178 static char *ld_bind_now; /* Environment variable for immediate binding */
179 static char *ld_debug; /* Environment variable for debugging */
180 static char *ld_library_path; /* Environment variable for search path */
181 static char *ld_preload; /* Environment variable for libraries to
183 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
184 static char *ld_tracing; /* Called from ldd to print libs */
185 static char *ld_utrace; /* Use utrace() to log events. */
186 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
187 static Obj_Entry **obj_tail; /* Link field of last object in list */
188 static Obj_Entry *obj_main; /* The main program shared object */
189 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
190 static unsigned int obj_count; /* Number of objects in obj_list */
191 static unsigned int obj_loads; /* Number of objects in obj_list */
193 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
194 STAILQ_HEAD_INITIALIZER(list_global);
195 static Objlist list_main = /* Objects loaded at program startup */
196 STAILQ_HEAD_INITIALIZER(list_main);
197 static Objlist list_fini = /* Objects needing fini() calls */
198 STAILQ_HEAD_INITIALIZER(list_fini);
200 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
202 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
204 extern Elf_Dyn _DYNAMIC;
205 #pragma weak _DYNAMIC
206 #ifndef RTLD_IS_DYNAMIC
207 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
210 int npagesizes, osreldate;
213 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
215 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
216 static int max_stack_flags;
219 * Global declarations normally provided by crt1. The dynamic linker is
220 * not built with crt1, so we have to provide them ourselves.
226 * Used to pass argc, argv to init functions.
232 * Globals to control TLS allocation.
234 size_t tls_last_offset; /* Static TLS offset of last module */
235 size_t tls_last_size; /* Static TLS size of last module */
236 size_t tls_static_space; /* Static TLS space allocated */
237 size_t tls_static_max_align;
238 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
239 int tls_max_index = 1; /* Largest module index allocated */
241 bool ld_library_path_rpath = false;
244 * Fill in a DoneList with an allocation large enough to hold all of
245 * the currently-loaded objects. Keep this as a macro since it calls
246 * alloca and we want that to occur within the scope of the caller.
248 #define donelist_init(dlp) \
249 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
250 assert((dlp)->objs != NULL), \
251 (dlp)->num_alloc = obj_count, \
254 #define UTRACE_DLOPEN_START 1
255 #define UTRACE_DLOPEN_STOP 2
256 #define UTRACE_DLCLOSE_START 3
257 #define UTRACE_DLCLOSE_STOP 4
258 #define UTRACE_LOAD_OBJECT 5
259 #define UTRACE_UNLOAD_OBJECT 6
260 #define UTRACE_ADD_RUNDEP 7
261 #define UTRACE_PRELOAD_FINISHED 8
262 #define UTRACE_INIT_CALL 9
263 #define UTRACE_FINI_CALL 10
266 char sig[4]; /* 'RTLD' */
269 void *mapbase; /* Used for 'parent' and 'init/fini' */
271 int refcnt; /* Used for 'mode' */
272 char name[MAXPATHLEN];
275 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
276 if (ld_utrace != NULL) \
277 ld_utrace_log(e, h, mb, ms, r, n); \
281 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
282 int refcnt, const char *name)
284 struct utrace_rtld ut;
292 ut.mapbase = mapbase;
293 ut.mapsize = mapsize;
295 bzero(ut.name, sizeof(ut.name));
297 strlcpy(ut.name, name, sizeof(ut.name));
298 utrace(&ut, sizeof(ut));
302 * Main entry point for dynamic linking. The first argument is the
303 * stack pointer. The stack is expected to be laid out as described
304 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
305 * Specifically, the stack pointer points to a word containing
306 * ARGC. Following that in the stack is a null-terminated sequence
307 * of pointers to argument strings. Then comes a null-terminated
308 * sequence of pointers to environment strings. Finally, there is a
309 * sequence of "auxiliary vector" entries.
311 * The second argument points to a place to store the dynamic linker's
312 * exit procedure pointer and the third to a place to store the main
315 * The return value is the main program's entry point.
318 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
320 Elf_Auxinfo *aux_info[AT_COUNT];
328 Objlist_Entry *entry;
330 Obj_Entry **preload_tail;
331 Obj_Entry *last_interposer;
333 RtldLockState lockstate;
334 char *library_path_rpath;
339 * On entry, the dynamic linker itself has not been relocated yet.
340 * Be very careful not to reference any global data until after
341 * init_rtld has returned. It is OK to reference file-scope statics
342 * and string constants, and to call static and global functions.
345 /* Find the auxiliary vector on the stack. */
348 sp += argc + 1; /* Skip over arguments and NULL terminator */
350 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
352 aux = (Elf_Auxinfo *) sp;
354 /* Digest the auxiliary vector. */
355 for (i = 0; i < AT_COUNT; i++)
357 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
358 if (auxp->a_type < AT_COUNT)
359 aux_info[auxp->a_type] = auxp;
362 /* Initialize and relocate ourselves. */
363 assert(aux_info[AT_BASE] != NULL);
364 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
366 __progname = obj_rtld.path;
367 argv0 = argv[0] != NULL ? argv[0] : "(null)";
372 if (aux_info[AT_CANARY] != NULL &&
373 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
374 i = aux_info[AT_CANARYLEN]->a_un.a_val;
375 if (i > sizeof(__stack_chk_guard))
376 i = sizeof(__stack_chk_guard);
377 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
382 len = sizeof(__stack_chk_guard);
383 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
384 len != sizeof(__stack_chk_guard)) {
385 /* If sysctl was unsuccessful, use the "terminator canary". */
386 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
387 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
388 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
389 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
393 trust = !issetugid();
395 ld_bind_now = getenv(LD_ "BIND_NOW");
397 * If the process is tainted, then we un-set the dangerous environment
398 * variables. The process will be marked as tainted until setuid(2)
399 * is called. If any child process calls setuid(2) we do not want any
400 * future processes to honor the potentially un-safe variables.
403 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
404 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
405 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
406 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
407 _rtld_error("environment corrupt; aborting");
411 ld_debug = getenv(LD_ "DEBUG");
412 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
413 libmap_override = getenv(LD_ "LIBMAP");
414 ld_library_path = getenv(LD_ "LIBRARY_PATH");
415 ld_preload = getenv(LD_ "PRELOAD");
416 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
417 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
418 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
419 if (library_path_rpath != NULL) {
420 if (library_path_rpath[0] == 'y' ||
421 library_path_rpath[0] == 'Y' ||
422 library_path_rpath[0] == '1')
423 ld_library_path_rpath = true;
425 ld_library_path_rpath = false;
427 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
428 (ld_library_path != NULL) || (ld_preload != NULL) ||
429 (ld_elf_hints_path != NULL) || ld_loadfltr;
430 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
431 ld_utrace = getenv(LD_ "UTRACE");
433 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
434 ld_elf_hints_path = _PATH_ELF_HINTS;
436 if (ld_debug != NULL && *ld_debug != '\0')
438 dbg("%s is initialized, base address = %p", __progname,
439 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
440 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
441 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
443 dbg("initializing thread locks");
447 * Load the main program, or process its program header if it is
450 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
451 int fd = aux_info[AT_EXECFD]->a_un.a_val;
452 dbg("loading main program");
453 obj_main = map_object(fd, argv0, NULL);
455 if (obj_main == NULL)
457 max_stack_flags = obj->stack_flags;
458 } else { /* Main program already loaded. */
459 const Elf_Phdr *phdr;
463 dbg("processing main program's program header");
464 assert(aux_info[AT_PHDR] != NULL);
465 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
466 assert(aux_info[AT_PHNUM] != NULL);
467 phnum = aux_info[AT_PHNUM]->a_un.a_val;
468 assert(aux_info[AT_PHENT] != NULL);
469 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
470 assert(aux_info[AT_ENTRY] != NULL);
471 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
472 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
476 if (aux_info[AT_EXECPATH] != 0) {
478 char buf[MAXPATHLEN];
480 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
481 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
482 if (kexecpath[0] == '/')
483 obj_main->path = kexecpath;
484 else if (getcwd(buf, sizeof(buf)) == NULL ||
485 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
486 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
487 obj_main->path = xstrdup(argv0);
489 obj_main->path = xstrdup(buf);
491 dbg("No AT_EXECPATH");
492 obj_main->path = xstrdup(argv0);
494 dbg("obj_main path %s", obj_main->path);
495 obj_main->mainprog = true;
497 if (aux_info[AT_STACKPROT] != NULL &&
498 aux_info[AT_STACKPROT]->a_un.a_val != 0)
499 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
503 * Get the actual dynamic linker pathname from the executable if
504 * possible. (It should always be possible.) That ensures that
505 * gdb will find the right dynamic linker even if a non-standard
508 if (obj_main->interp != NULL &&
509 strcmp(obj_main->interp, obj_rtld.path) != 0) {
511 obj_rtld.path = xstrdup(obj_main->interp);
512 __progname = obj_rtld.path;
516 digest_dynamic(obj_main, 0);
517 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
518 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
519 obj_main->dynsymcount);
521 linkmap_add(obj_main);
522 linkmap_add(&obj_rtld);
524 /* Link the main program into the list of objects. */
525 *obj_tail = obj_main;
526 obj_tail = &obj_main->next;
530 /* Initialize a fake symbol for resolving undefined weak references. */
531 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
532 sym_zero.st_shndx = SHN_UNDEF;
533 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
536 libmap_disable = (bool)lm_init(libmap_override);
538 dbg("loading LD_PRELOAD libraries");
539 if (load_preload_objects() == -1)
541 preload_tail = obj_tail;
543 dbg("loading needed objects");
544 if (load_needed_objects(obj_main, 0) == -1)
547 /* Make a list of all objects loaded at startup. */
548 last_interposer = obj_main;
549 for (obj = obj_list; obj != NULL; obj = obj->next) {
550 if (obj->z_interpose && obj != obj_main) {
551 objlist_put_after(&list_main, last_interposer, obj);
552 last_interposer = obj;
554 objlist_push_tail(&list_main, obj);
559 dbg("checking for required versions");
560 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
563 if (ld_tracing) { /* We're done */
564 trace_loaded_objects(obj_main);
568 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
569 dump_relocations(obj_main);
574 * Processing tls relocations requires having the tls offsets
575 * initialized. Prepare offsets before starting initial
576 * relocation processing.
578 dbg("initializing initial thread local storage offsets");
579 STAILQ_FOREACH(entry, &list_main, link) {
581 * Allocate all the initial objects out of the static TLS
582 * block even if they didn't ask for it.
584 allocate_tls_offset(entry->obj);
587 if (relocate_objects(obj_main,
588 ld_bind_now != NULL && *ld_bind_now != '\0',
589 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
592 dbg("doing copy relocations");
593 if (do_copy_relocations(obj_main) == -1)
596 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
597 dump_relocations(obj_main);
602 * Setup TLS for main thread. This must be done after the
603 * relocations are processed, since tls initialization section
604 * might be the subject for relocations.
606 dbg("initializing initial thread local storage");
607 allocate_initial_tls(obj_list);
609 dbg("initializing key program variables");
610 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
611 set_program_var("environ", env);
612 set_program_var("__elf_aux_vector", aux);
614 /* Make a list of init functions to call. */
615 objlist_init(&initlist);
616 initlist_add_objects(obj_list, preload_tail, &initlist);
618 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
620 map_stacks_exec(NULL);
622 dbg("resolving ifuncs");
623 if (resolve_objects_ifunc(obj_main,
624 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
628 if (!obj_main->crt_no_init) {
630 * Make sure we don't call the main program's init and fini
631 * functions for binaries linked with old crt1 which calls
634 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
635 obj_main->preinit_array = obj_main->init_array =
636 obj_main->fini_array = (Elf_Addr)NULL;
639 wlock_acquire(rtld_bind_lock, &lockstate);
640 if (obj_main->crt_no_init)
642 objlist_call_init(&initlist, &lockstate);
643 _r_debug_postinit(&obj_main->linkmap);
644 objlist_clear(&initlist);
645 dbg("loading filtees");
646 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
647 if (ld_loadfltr || obj->z_loadfltr)
648 load_filtees(obj, 0, &lockstate);
650 lock_release(rtld_bind_lock, &lockstate);
652 dbg("transferring control to program entry point = %p", obj_main->entry);
654 /* Return the exit procedure and the program entry point. */
655 *exit_proc = rtld_exit;
657 return (func_ptr_type) obj_main->entry;
661 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
666 ptr = (void *)make_function_pointer(def, obj);
667 target = ((Elf_Addr (*)(void))ptr)();
668 return ((void *)target);
672 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
676 const Obj_Entry *defobj;
679 RtldLockState lockstate;
681 rlock_acquire(rtld_bind_lock, &lockstate);
682 if (sigsetjmp(lockstate.env, 0) != 0)
683 lock_upgrade(rtld_bind_lock, &lockstate);
685 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
687 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
689 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
690 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
694 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
695 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
697 target = (Elf_Addr)(defobj->relocbase + def->st_value);
699 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
700 defobj->strtab + def->st_name, basename(obj->path),
701 (void *)target, basename(defobj->path));
704 * Write the new contents for the jmpslot. Note that depending on
705 * architecture, the value which we need to return back to the
706 * lazy binding trampoline may or may not be the target
707 * address. The value returned from reloc_jmpslot() is the value
708 * that the trampoline needs.
710 target = reloc_jmpslot(where, target, defobj, obj, rel);
711 lock_release(rtld_bind_lock, &lockstate);
716 * Error reporting function. Use it like printf. If formats the message
717 * into a buffer, and sets things up so that the next call to dlerror()
718 * will return the message.
721 _rtld_error(const char *fmt, ...)
723 static char buf[512];
727 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
733 * Return a dynamically-allocated copy of the current error message, if any.
738 return error_message == NULL ? NULL : xstrdup(error_message);
742 * Restore the current error message from a copy which was previously saved
743 * by errmsg_save(). The copy is freed.
746 errmsg_restore(char *saved_msg)
748 if (saved_msg == NULL)
749 error_message = NULL;
751 _rtld_error("%s", saved_msg);
757 basename(const char *name)
759 const char *p = strrchr(name, '/');
760 return p != NULL ? p + 1 : name;
763 static struct utsname uts;
766 origin_subst_one(char *real, const char *kw, const char *subst,
769 char *p, *p1, *res, *resp;
770 int subst_len, kw_len, subst_count, old_len, new_len;
775 * First, count the number of the keyword occurences, to
776 * preallocate the final string.
778 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
785 * If the keyword is not found, just return.
787 if (subst_count == 0)
788 return (may_free ? real : xstrdup(real));
791 * There is indeed something to substitute. Calculate the
792 * length of the resulting string, and allocate it.
794 subst_len = strlen(subst);
795 old_len = strlen(real);
796 new_len = old_len + (subst_len - kw_len) * subst_count;
797 res = xmalloc(new_len + 1);
800 * Now, execute the substitution loop.
802 for (p = real, resp = res, *resp = '\0';;) {
805 /* Copy the prefix before keyword. */
806 memcpy(resp, p, p1 - p);
808 /* Keyword replacement. */
809 memcpy(resp, subst, subst_len);
817 /* Copy to the end of string and finish. */
825 origin_subst(char *real, const char *origin_path)
827 char *res1, *res2, *res3, *res4;
829 if (uts.sysname[0] == '\0') {
830 if (uname(&uts) != 0) {
831 _rtld_error("utsname failed: %d", errno);
835 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
836 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
837 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
838 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
845 const char *msg = dlerror();
849 rtld_fdputstr(STDERR_FILENO, msg);
850 rtld_fdputchar(STDERR_FILENO, '\n');
855 * Process a shared object's DYNAMIC section, and save the important
856 * information in its Obj_Entry structure.
859 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
860 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
863 Needed_Entry **needed_tail = &obj->needed;
864 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
865 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
866 const Elf_Hashelt *hashtab;
867 const Elf32_Word *hashval;
868 Elf32_Word bkt, nmaskwords;
870 int plttype = DT_REL;
876 obj->bind_now = false;
877 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
878 switch (dynp->d_tag) {
881 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
885 obj->relsize = dynp->d_un.d_val;
889 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
893 obj->pltrel = (const Elf_Rel *)
894 (obj->relocbase + dynp->d_un.d_ptr);
898 obj->pltrelsize = dynp->d_un.d_val;
902 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
906 obj->relasize = dynp->d_un.d_val;
910 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
914 plttype = dynp->d_un.d_val;
915 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
919 obj->symtab = (const Elf_Sym *)
920 (obj->relocbase + dynp->d_un.d_ptr);
924 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
928 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
932 obj->strsize = dynp->d_un.d_val;
936 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
941 obj->verneednum = dynp->d_un.d_val;
945 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
950 obj->verdefnum = dynp->d_un.d_val;
954 obj->versyms = (const Elf_Versym *)(obj->relocbase +
960 hashtab = (const Elf_Hashelt *)(obj->relocbase +
962 obj->nbuckets = hashtab[0];
963 obj->nchains = hashtab[1];
964 obj->buckets = hashtab + 2;
965 obj->chains = obj->buckets + obj->nbuckets;
966 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
967 obj->buckets != NULL;
973 hashtab = (const Elf_Hashelt *)(obj->relocbase +
975 obj->nbuckets_gnu = hashtab[0];
976 obj->symndx_gnu = hashtab[1];
977 nmaskwords = hashtab[2];
978 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
979 obj->maskwords_bm_gnu = nmaskwords - 1;
980 obj->shift2_gnu = hashtab[3];
981 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
982 obj->buckets_gnu = hashtab + 4 + bloom_size32;
983 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
985 /* Number of bitmask words is required to be power of 2 */
986 obj->valid_hash_gnu = powerof2(nmaskwords) &&
987 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
993 Needed_Entry *nep = NEW(Needed_Entry);
994 nep->name = dynp->d_un.d_val;
999 needed_tail = &nep->next;
1005 Needed_Entry *nep = NEW(Needed_Entry);
1006 nep->name = dynp->d_un.d_val;
1010 *needed_filtees_tail = nep;
1011 needed_filtees_tail = &nep->next;
1017 Needed_Entry *nep = NEW(Needed_Entry);
1018 nep->name = dynp->d_un.d_val;
1022 *needed_aux_filtees_tail = nep;
1023 needed_aux_filtees_tail = &nep->next;
1028 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1032 obj->textrel = true;
1036 obj->symbolic = true;
1041 * We have to wait until later to process this, because we
1042 * might not have gotten the address of the string table yet.
1052 *dyn_runpath = dynp;
1056 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1059 case DT_PREINIT_ARRAY:
1060 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1063 case DT_PREINIT_ARRAYSZ:
1064 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1068 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1071 case DT_INIT_ARRAYSZ:
1072 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1076 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1080 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1083 case DT_FINI_ARRAYSZ:
1084 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1088 * Don't process DT_DEBUG on MIPS as the dynamic section
1089 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1094 /* XXX - not implemented yet */
1096 dbg("Filling in DT_DEBUG entry");
1097 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1102 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1103 obj->z_origin = true;
1104 if (dynp->d_un.d_val & DF_SYMBOLIC)
1105 obj->symbolic = true;
1106 if (dynp->d_un.d_val & DF_TEXTREL)
1107 obj->textrel = true;
1108 if (dynp->d_un.d_val & DF_BIND_NOW)
1109 obj->bind_now = true;
1110 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1114 case DT_MIPS_LOCAL_GOTNO:
1115 obj->local_gotno = dynp->d_un.d_val;
1118 case DT_MIPS_SYMTABNO:
1119 obj->symtabno = dynp->d_un.d_val;
1122 case DT_MIPS_GOTSYM:
1123 obj->gotsym = dynp->d_un.d_val;
1126 case DT_MIPS_RLD_MAP:
1127 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1132 if (dynp->d_un.d_val & DF_1_NOOPEN)
1133 obj->z_noopen = true;
1134 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1135 obj->z_origin = true;
1136 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1138 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1139 obj->bind_now = true;
1140 if (dynp->d_un.d_val & DF_1_NODELETE)
1141 obj->z_nodelete = true;
1142 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1143 obj->z_loadfltr = true;
1144 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1145 obj->z_interpose = true;
1146 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1147 obj->z_nodeflib = true;
1152 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1159 obj->traced = false;
1161 if (plttype == DT_RELA) {
1162 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1164 obj->pltrelasize = obj->pltrelsize;
1165 obj->pltrelsize = 0;
1168 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1169 if (obj->valid_hash_sysv)
1170 obj->dynsymcount = obj->nchains;
1171 else if (obj->valid_hash_gnu) {
1172 obj->dynsymcount = 0;
1173 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1174 if (obj->buckets_gnu[bkt] == 0)
1176 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1179 while ((*hashval++ & 1u) == 0);
1181 obj->dynsymcount += obj->symndx_gnu;
1186 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1187 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1190 if (obj->z_origin && obj->origin_path == NULL) {
1191 obj->origin_path = xmalloc(PATH_MAX);
1192 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1196 if (dyn_runpath != NULL) {
1197 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1199 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1201 else if (dyn_rpath != NULL) {
1202 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1204 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1207 if (dyn_soname != NULL)
1208 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1212 digest_dynamic(Obj_Entry *obj, int early)
1214 const Elf_Dyn *dyn_rpath;
1215 const Elf_Dyn *dyn_soname;
1216 const Elf_Dyn *dyn_runpath;
1218 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1219 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1223 * Process a shared object's program header. This is used only for the
1224 * main program, when the kernel has already loaded the main program
1225 * into memory before calling the dynamic linker. It creates and
1226 * returns an Obj_Entry structure.
1229 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1232 const Elf_Phdr *phlimit = phdr + phnum;
1234 Elf_Addr note_start, note_end;
1238 for (ph = phdr; ph < phlimit; ph++) {
1239 if (ph->p_type != PT_PHDR)
1243 obj->phsize = ph->p_memsz;
1244 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1248 obj->stack_flags = PF_X | PF_R | PF_W;
1250 for (ph = phdr; ph < phlimit; ph++) {
1251 switch (ph->p_type) {
1254 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1258 if (nsegs == 0) { /* First load segment */
1259 obj->vaddrbase = trunc_page(ph->p_vaddr);
1260 obj->mapbase = obj->vaddrbase + obj->relocbase;
1261 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1263 } else { /* Last load segment */
1264 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1271 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1276 obj->tlssize = ph->p_memsz;
1277 obj->tlsalign = ph->p_align;
1278 obj->tlsinitsize = ph->p_filesz;
1279 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1283 obj->stack_flags = ph->p_flags;
1287 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1288 obj->relro_size = round_page(ph->p_memsz);
1292 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1293 note_end = note_start + ph->p_filesz;
1294 digest_notes(obj, note_start, note_end);
1299 _rtld_error("%s: too few PT_LOAD segments", path);
1308 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1310 const Elf_Note *note;
1311 const char *note_name;
1314 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1315 note = (const Elf_Note *)((const char *)(note + 1) +
1316 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1317 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1318 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1319 note->n_descsz != sizeof(int32_t))
1321 if (note->n_type != ABI_NOTETYPE &&
1322 note->n_type != CRT_NOINIT_NOTETYPE)
1324 note_name = (const char *)(note + 1);
1325 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1326 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1328 switch (note->n_type) {
1330 /* FreeBSD osrel note */
1331 p = (uintptr_t)(note + 1);
1332 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1333 obj->osrel = *(const int32_t *)(p);
1334 dbg("note osrel %d", obj->osrel);
1336 case CRT_NOINIT_NOTETYPE:
1337 /* FreeBSD 'crt does not call init' note */
1338 obj->crt_no_init = true;
1339 dbg("note crt_no_init");
1346 dlcheck(void *handle)
1350 for (obj = obj_list; obj != NULL; obj = obj->next)
1351 if (obj == (Obj_Entry *) handle)
1354 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1355 _rtld_error("Invalid shared object handle %p", handle);
1362 * If the given object is already in the donelist, return true. Otherwise
1363 * add the object to the list and return false.
1366 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1370 for (i = 0; i < dlp->num_used; i++)
1371 if (dlp->objs[i] == obj)
1374 * Our donelist allocation should always be sufficient. But if
1375 * our threads locking isn't working properly, more shared objects
1376 * could have been loaded since we allocated the list. That should
1377 * never happen, but we'll handle it properly just in case it does.
1379 if (dlp->num_used < dlp->num_alloc)
1380 dlp->objs[dlp->num_used++] = obj;
1385 * Hash function for symbol table lookup. Don't even think about changing
1386 * this. It is specified by the System V ABI.
1389 elf_hash(const char *name)
1391 const unsigned char *p = (const unsigned char *) name;
1392 unsigned long h = 0;
1395 while (*p != '\0') {
1396 h = (h << 4) + *p++;
1397 if ((g = h & 0xf0000000) != 0)
1405 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1406 * unsigned in case it's implemented with a wider type.
1409 gnu_hash(const char *s)
1415 for (c = *s; c != '\0'; c = *++s)
1417 return (h & 0xffffffff);
1421 * Find the library with the given name, and return its full pathname.
1422 * The returned string is dynamically allocated. Generates an error
1423 * message and returns NULL if the library cannot be found.
1425 * If the second argument is non-NULL, then it refers to an already-
1426 * loaded shared object, whose library search path will be searched.
1428 * The search order is:
1429 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1430 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1432 * DT_RUNPATH in the referencing file
1433 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1435 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1437 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1440 find_library(const char *xname, const Obj_Entry *refobj)
1444 bool nodeflib, objgiven;
1446 objgiven = refobj != NULL;
1447 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1448 if (xname[0] != '/' && !trust) {
1449 _rtld_error("Absolute pathname required for shared object \"%s\"",
1453 if (objgiven && refobj->z_origin) {
1454 return (origin_subst(__DECONST(char *, xname),
1455 refobj->origin_path));
1457 return (xstrdup(xname));
1461 if (libmap_disable || !objgiven ||
1462 (name = lm_find(refobj->path, xname)) == NULL)
1463 name = (char *)xname;
1465 dbg(" Searching for \"%s\"", name);
1468 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1469 * back to pre-conforming behaviour if user requested so with
1470 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1473 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1474 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1476 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1477 (pathname = search_library_path(name, gethints(false))) != NULL ||
1478 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1481 nodeflib = objgiven ? refobj->z_nodeflib : false;
1483 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1484 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1485 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1486 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1488 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1489 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1490 (objgiven && !nodeflib &&
1491 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1495 if (objgiven && refobj->path != NULL) {
1496 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1497 name, basename(refobj->path));
1499 _rtld_error("Shared object \"%s\" not found", name);
1505 * Given a symbol number in a referencing object, find the corresponding
1506 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1507 * no definition was found. Returns a pointer to the Obj_Entry of the
1508 * defining object via the reference parameter DEFOBJ_OUT.
1511 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1512 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1513 RtldLockState *lockstate)
1517 const Obj_Entry *defobj;
1523 * If we have already found this symbol, get the information from
1526 if (symnum >= refobj->dynsymcount)
1527 return NULL; /* Bad object */
1528 if (cache != NULL && cache[symnum].sym != NULL) {
1529 *defobj_out = cache[symnum].obj;
1530 return cache[symnum].sym;
1533 ref = refobj->symtab + symnum;
1534 name = refobj->strtab + ref->st_name;
1539 * We don't have to do a full scale lookup if the symbol is local.
1540 * We know it will bind to the instance in this load module; to
1541 * which we already have a pointer (ie ref). By not doing a lookup,
1542 * we not only improve performance, but it also avoids unresolvable
1543 * symbols when local symbols are not in the hash table. This has
1544 * been seen with the ia64 toolchain.
1546 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1547 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1548 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1551 symlook_init(&req, name);
1553 req.ventry = fetch_ventry(refobj, symnum);
1554 req.lockstate = lockstate;
1555 res = symlook_default(&req, refobj);
1558 defobj = req.defobj_out;
1566 * If we found no definition and the reference is weak, treat the
1567 * symbol as having the value zero.
1569 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1575 *defobj_out = defobj;
1576 /* Record the information in the cache to avoid subsequent lookups. */
1577 if (cache != NULL) {
1578 cache[symnum].sym = def;
1579 cache[symnum].obj = defobj;
1582 if (refobj != &obj_rtld)
1583 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1589 * Return the search path from the ldconfig hints file, reading it if
1590 * necessary. If nostdlib is true, then the default search paths are
1591 * not added to result.
1593 * Returns NULL if there are problems with the hints file,
1594 * or if the search path there is empty.
1597 gethints(bool nostdlib)
1599 static char *hints, *filtered_path;
1600 struct elfhints_hdr hdr;
1601 struct fill_search_info_args sargs, hargs;
1602 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1603 struct dl_serpath *SLPpath, *hintpath;
1605 unsigned int SLPndx, hintndx, fndx, fcount;
1610 /* First call, read the hints file */
1611 if (hints == NULL) {
1612 /* Keep from trying again in case the hints file is bad. */
1615 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1617 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1618 hdr.magic != ELFHINTS_MAGIC ||
1623 p = xmalloc(hdr.dirlistlen + 1);
1624 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1625 read(fd, p, hdr.dirlistlen + 1) !=
1626 (ssize_t)hdr.dirlistlen + 1) {
1636 * If caller agreed to receive list which includes the default
1637 * paths, we are done. Otherwise, if we still did not
1638 * calculated filtered result, do it now.
1641 return (hints[0] != '\0' ? hints : NULL);
1642 if (filtered_path != NULL)
1646 * Obtain the list of all configured search paths, and the
1647 * list of the default paths.
1649 * First estimate the size of the results.
1651 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1653 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1656 sargs.request = RTLD_DI_SERINFOSIZE;
1657 sargs.serinfo = &smeta;
1658 hargs.request = RTLD_DI_SERINFOSIZE;
1659 hargs.serinfo = &hmeta;
1661 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1662 path_enumerate(p, fill_search_info, &hargs);
1664 SLPinfo = xmalloc(smeta.dls_size);
1665 hintinfo = xmalloc(hmeta.dls_size);
1668 * Next fetch both sets of paths.
1670 sargs.request = RTLD_DI_SERINFO;
1671 sargs.serinfo = SLPinfo;
1672 sargs.serpath = &SLPinfo->dls_serpath[0];
1673 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1675 hargs.request = RTLD_DI_SERINFO;
1676 hargs.serinfo = hintinfo;
1677 hargs.serpath = &hintinfo->dls_serpath[0];
1678 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1680 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1681 path_enumerate(p, fill_search_info, &hargs);
1684 * Now calculate the difference between two sets, by excluding
1685 * standard paths from the full set.
1689 filtered_path = xmalloc(hdr.dirlistlen + 1);
1690 hintpath = &hintinfo->dls_serpath[0];
1691 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1693 SLPpath = &SLPinfo->dls_serpath[0];
1695 * Check each standard path against current.
1697 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1698 /* matched, skip the path */
1699 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1707 * Not matched against any standard path, add the path
1708 * to result. Separate consequtive paths with ':'.
1711 filtered_path[fndx] = ':';
1715 flen = strlen(hintpath->dls_name);
1716 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1719 filtered_path[fndx] = '\0';
1725 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1729 init_dag(Obj_Entry *root)
1731 const Needed_Entry *needed;
1732 const Objlist_Entry *elm;
1735 if (root->dag_inited)
1737 donelist_init(&donelist);
1739 /* Root object belongs to own DAG. */
1740 objlist_push_tail(&root->dldags, root);
1741 objlist_push_tail(&root->dagmembers, root);
1742 donelist_check(&donelist, root);
1745 * Add dependencies of root object to DAG in breadth order
1746 * by exploiting the fact that each new object get added
1747 * to the tail of the dagmembers list.
1749 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1750 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1751 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1753 objlist_push_tail(&needed->obj->dldags, root);
1754 objlist_push_tail(&root->dagmembers, needed->obj);
1757 root->dag_inited = true;
1761 process_nodelete(Obj_Entry *root)
1763 const Objlist_Entry *elm;
1766 * Walk over object DAG and process every dependent object that
1767 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1768 * which then should have its reference upped separately.
1770 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1771 if (elm->obj != NULL && elm->obj->z_nodelete &&
1772 !elm->obj->ref_nodel) {
1773 dbg("obj %s nodelete", elm->obj->path);
1776 elm->obj->ref_nodel = true;
1781 * Initialize the dynamic linker. The argument is the address at which
1782 * the dynamic linker has been mapped into memory. The primary task of
1783 * this function is to relocate the dynamic linker.
1786 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1788 Obj_Entry objtmp; /* Temporary rtld object */
1789 const Elf_Dyn *dyn_rpath;
1790 const Elf_Dyn *dyn_soname;
1791 const Elf_Dyn *dyn_runpath;
1794 * Conjure up an Obj_Entry structure for the dynamic linker.
1796 * The "path" member can't be initialized yet because string constants
1797 * cannot yet be accessed. Below we will set it correctly.
1799 memset(&objtmp, 0, sizeof(objtmp));
1802 objtmp.mapbase = mapbase;
1804 objtmp.relocbase = mapbase;
1806 if (RTLD_IS_DYNAMIC()) {
1807 objtmp.dynamic = rtld_dynamic(&objtmp);
1808 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1809 assert(objtmp.needed == NULL);
1810 #if !defined(__mips__)
1811 /* MIPS has a bogus DT_TEXTREL. */
1812 assert(!objtmp.textrel);
1816 * Temporarily put the dynamic linker entry into the object list, so
1817 * that symbols can be found.
1820 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1823 /* Initialize the object list. */
1824 obj_tail = &obj_list;
1826 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1827 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1829 /* The page size is required by the dynamic memory allocator. */
1830 init_pagesizes(aux_info);
1832 if (aux_info[AT_OSRELDATE] != NULL)
1833 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1835 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1837 /* Replace the path with a dynamically allocated copy. */
1838 obj_rtld.path = xstrdup(PATH_RTLD);
1840 r_debug.r_brk = r_debug_state;
1841 r_debug.r_state = RT_CONSISTENT;
1845 * Retrieve the array of supported page sizes. The kernel provides the page
1846 * sizes in increasing order.
1849 init_pagesizes(Elf_Auxinfo **aux_info)
1851 static size_t psa[MAXPAGESIZES];
1855 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1857 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1858 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1861 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1864 /* As a fallback, retrieve the base page size. */
1865 size = sizeof(psa[0]);
1866 if (aux_info[AT_PAGESZ] != NULL) {
1867 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1871 mib[1] = HW_PAGESIZE;
1875 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1876 _rtld_error("sysctl for hw.pagesize(s) failed");
1882 npagesizes = size / sizeof(pagesizes[0]);
1883 /* Discard any invalid entries at the end of the array. */
1884 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1889 * Add the init functions from a needed object list (and its recursive
1890 * needed objects) to "list". This is not used directly; it is a helper
1891 * function for initlist_add_objects(). The write lock must be held
1892 * when this function is called.
1895 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1897 /* Recursively process the successor needed objects. */
1898 if (needed->next != NULL)
1899 initlist_add_neededs(needed->next, list);
1901 /* Process the current needed object. */
1902 if (needed->obj != NULL)
1903 initlist_add_objects(needed->obj, &needed->obj->next, list);
1907 * Scan all of the DAGs rooted in the range of objects from "obj" to
1908 * "tail" and add their init functions to "list". This recurses over
1909 * the DAGs and ensure the proper init ordering such that each object's
1910 * needed libraries are initialized before the object itself. At the
1911 * same time, this function adds the objects to the global finalization
1912 * list "list_fini" in the opposite order. The write lock must be
1913 * held when this function is called.
1916 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1919 if (obj->init_scanned || obj->init_done)
1921 obj->init_scanned = true;
1923 /* Recursively process the successor objects. */
1924 if (&obj->next != tail)
1925 initlist_add_objects(obj->next, tail, list);
1927 /* Recursively process the needed objects. */
1928 if (obj->needed != NULL)
1929 initlist_add_neededs(obj->needed, list);
1930 if (obj->needed_filtees != NULL)
1931 initlist_add_neededs(obj->needed_filtees, list);
1932 if (obj->needed_aux_filtees != NULL)
1933 initlist_add_neededs(obj->needed_aux_filtees, list);
1935 /* Add the object to the init list. */
1936 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1937 obj->init_array != (Elf_Addr)NULL)
1938 objlist_push_tail(list, obj);
1940 /* Add the object to the global fini list in the reverse order. */
1941 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1942 && !obj->on_fini_list) {
1943 objlist_push_head(&list_fini, obj);
1944 obj->on_fini_list = true;
1949 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1953 free_needed_filtees(Needed_Entry *n)
1955 Needed_Entry *needed, *needed1;
1957 for (needed = n; needed != NULL; needed = needed->next) {
1958 if (needed->obj != NULL) {
1959 dlclose(needed->obj);
1963 for (needed = n; needed != NULL; needed = needed1) {
1964 needed1 = needed->next;
1970 unload_filtees(Obj_Entry *obj)
1973 free_needed_filtees(obj->needed_filtees);
1974 obj->needed_filtees = NULL;
1975 free_needed_filtees(obj->needed_aux_filtees);
1976 obj->needed_aux_filtees = NULL;
1977 obj->filtees_loaded = false;
1981 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
1982 RtldLockState *lockstate)
1985 for (; needed != NULL; needed = needed->next) {
1986 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1987 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1988 RTLD_LOCAL, lockstate);
1993 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1996 lock_restart_for_upgrade(lockstate);
1997 if (!obj->filtees_loaded) {
1998 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
1999 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2000 obj->filtees_loaded = true;
2005 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2009 for (; needed != NULL; needed = needed->next) {
2010 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2011 flags & ~RTLD_LO_NOLOAD);
2012 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2019 * Given a shared object, traverse its list of needed objects, and load
2020 * each of them. Returns 0 on success. Generates an error message and
2021 * returns -1 on failure.
2024 load_needed_objects(Obj_Entry *first, int flags)
2028 for (obj = first; obj != NULL; obj = obj->next) {
2029 if (process_needed(obj, obj->needed, flags) == -1)
2036 load_preload_objects(void)
2038 char *p = ld_preload;
2040 static const char delim[] = " \t:;";
2045 p += strspn(p, delim);
2046 while (*p != '\0') {
2047 size_t len = strcspn(p, delim);
2052 obj = load_object(p, -1, NULL, 0);
2054 return -1; /* XXX - cleanup */
2055 obj->z_interpose = true;
2058 p += strspn(p, delim);
2060 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2065 printable_path(const char *path)
2068 return (path == NULL ? "<unknown>" : path);
2072 * Load a shared object into memory, if it is not already loaded. The
2073 * object may be specified by name or by user-supplied file descriptor
2074 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2077 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2081 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2089 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2090 if (object_match_name(obj, name))
2094 path = find_library(name, refobj);
2101 * If we didn't find a match by pathname, or the name is not
2102 * supplied, open the file and check again by device and inode.
2103 * This avoids false mismatches caused by multiple links or ".."
2106 * To avoid a race, we open the file and use fstat() rather than
2111 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2112 _rtld_error("Cannot open \"%s\"", path);
2117 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2119 _rtld_error("Cannot dup fd");
2124 if (fstat(fd, &sb) == -1) {
2125 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2130 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2131 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2133 if (obj != NULL && name != NULL) {
2134 object_add_name(obj, name);
2139 if (flags & RTLD_LO_NOLOAD) {
2145 /* First use of this object, so we must map it in */
2146 obj = do_load_object(fd, name, path, &sb, flags);
2155 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2162 * but first, make sure that environment variables haven't been
2163 * used to circumvent the noexec flag on a filesystem.
2165 if (dangerous_ld_env) {
2166 if (fstatfs(fd, &fs) != 0) {
2167 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2170 if (fs.f_flags & MNT_NOEXEC) {
2171 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2175 dbg("loading \"%s\"", printable_path(path));
2176 obj = map_object(fd, printable_path(path), sbp);
2181 * If DT_SONAME is present in the object, digest_dynamic2 already
2182 * added it to the object names.
2185 object_add_name(obj, name);
2187 digest_dynamic(obj, 0);
2188 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2189 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2190 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2192 dbg("refusing to load non-loadable \"%s\"", obj->path);
2193 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2194 munmap(obj->mapbase, obj->mapsize);
2199 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2201 obj_tail = &obj->next;
2204 linkmap_add(obj); /* for GDB & dlinfo() */
2205 max_stack_flags |= obj->stack_flags;
2207 dbg(" %p .. %p: %s", obj->mapbase,
2208 obj->mapbase + obj->mapsize - 1, obj->path);
2210 dbg(" WARNING: %s has impure text", obj->path);
2211 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2218 obj_from_addr(const void *addr)
2222 for (obj = obj_list; obj != NULL; obj = obj->next) {
2223 if (addr < (void *) obj->mapbase)
2225 if (addr < (void *) (obj->mapbase + obj->mapsize))
2234 Elf_Addr *preinit_addr;
2237 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2238 if (preinit_addr == NULL)
2241 for (index = 0; index < obj_main->preinit_array_num; index++) {
2242 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2243 dbg("calling preinit function for %s at %p", obj_main->path,
2244 (void *)preinit_addr[index]);
2245 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2246 0, 0, obj_main->path);
2247 call_init_pointer(obj_main, preinit_addr[index]);
2253 * Call the finalization functions for each of the objects in "list"
2254 * belonging to the DAG of "root" and referenced once. If NULL "root"
2255 * is specified, every finalization function will be called regardless
2256 * of the reference count and the list elements won't be freed. All of
2257 * the objects are expected to have non-NULL fini functions.
2260 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2264 Elf_Addr *fini_addr;
2267 assert(root == NULL || root->refcount == 1);
2270 * Preserve the current error message since a fini function might
2271 * call into the dynamic linker and overwrite it.
2273 saved_msg = errmsg_save();
2275 STAILQ_FOREACH(elm, list, link) {
2276 if (root != NULL && (elm->obj->refcount != 1 ||
2277 objlist_find(&root->dagmembers, elm->obj) == NULL))
2279 /* Remove object from fini list to prevent recursive invocation. */
2280 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2282 * XXX: If a dlopen() call references an object while the
2283 * fini function is in progress, we might end up trying to
2284 * unload the referenced object in dlclose() or the object
2285 * won't be unloaded although its fini function has been
2288 lock_release(rtld_bind_lock, lockstate);
2291 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2292 * When this happens, DT_FINI_ARRAY is processed first.
2294 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2295 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2296 for (index = elm->obj->fini_array_num - 1; index >= 0;
2298 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2299 dbg("calling fini function for %s at %p",
2300 elm->obj->path, (void *)fini_addr[index]);
2301 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2302 (void *)fini_addr[index], 0, 0, elm->obj->path);
2303 call_initfini_pointer(elm->obj, fini_addr[index]);
2307 if (elm->obj->fini != (Elf_Addr)NULL) {
2308 dbg("calling fini function for %s at %p", elm->obj->path,
2309 (void *)elm->obj->fini);
2310 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2311 0, 0, elm->obj->path);
2312 call_initfini_pointer(elm->obj, elm->obj->fini);
2314 wlock_acquire(rtld_bind_lock, lockstate);
2315 /* No need to free anything if process is going down. */
2319 * We must restart the list traversal after every fini call
2320 * because a dlclose() call from the fini function or from
2321 * another thread might have modified the reference counts.
2325 } while (elm != NULL);
2326 errmsg_restore(saved_msg);
2330 * Call the initialization functions for each of the objects in
2331 * "list". All of the objects are expected to have non-NULL init
2335 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2340 Elf_Addr *init_addr;
2344 * Clean init_scanned flag so that objects can be rechecked and
2345 * possibly initialized earlier if any of vectors called below
2346 * cause the change by using dlopen.
2348 for (obj = obj_list; obj != NULL; obj = obj->next)
2349 obj->init_scanned = false;
2352 * Preserve the current error message since an init function might
2353 * call into the dynamic linker and overwrite it.
2355 saved_msg = errmsg_save();
2356 STAILQ_FOREACH(elm, list, link) {
2357 if (elm->obj->init_done) /* Initialized early. */
2360 * Race: other thread might try to use this object before current
2361 * one completes the initilization. Not much can be done here
2362 * without better locking.
2364 elm->obj->init_done = true;
2365 lock_release(rtld_bind_lock, lockstate);
2368 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2369 * When this happens, DT_INIT is processed first.
2371 if (elm->obj->init != (Elf_Addr)NULL) {
2372 dbg("calling init function for %s at %p", elm->obj->path,
2373 (void *)elm->obj->init);
2374 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2375 0, 0, elm->obj->path);
2376 call_initfini_pointer(elm->obj, elm->obj->init);
2378 init_addr = (Elf_Addr *)elm->obj->init_array;
2379 if (init_addr != NULL) {
2380 for (index = 0; index < elm->obj->init_array_num; index++) {
2381 if (init_addr[index] != 0 && init_addr[index] != 1) {
2382 dbg("calling init function for %s at %p", elm->obj->path,
2383 (void *)init_addr[index]);
2384 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2385 (void *)init_addr[index], 0, 0, elm->obj->path);
2386 call_init_pointer(elm->obj, init_addr[index]);
2390 wlock_acquire(rtld_bind_lock, lockstate);
2392 errmsg_restore(saved_msg);
2396 objlist_clear(Objlist *list)
2400 while (!STAILQ_EMPTY(list)) {
2401 elm = STAILQ_FIRST(list);
2402 STAILQ_REMOVE_HEAD(list, link);
2407 static Objlist_Entry *
2408 objlist_find(Objlist *list, const Obj_Entry *obj)
2412 STAILQ_FOREACH(elm, list, link)
2413 if (elm->obj == obj)
2419 objlist_init(Objlist *list)
2425 objlist_push_head(Objlist *list, Obj_Entry *obj)
2429 elm = NEW(Objlist_Entry);
2431 STAILQ_INSERT_HEAD(list, elm, link);
2435 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2439 elm = NEW(Objlist_Entry);
2441 STAILQ_INSERT_TAIL(list, elm, link);
2445 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2447 Objlist_Entry *elm, *listelm;
2449 STAILQ_FOREACH(listelm, list, link) {
2450 if (listelm->obj == listobj)
2453 elm = NEW(Objlist_Entry);
2455 if (listelm != NULL)
2456 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2458 STAILQ_INSERT_TAIL(list, elm, link);
2462 objlist_remove(Objlist *list, Obj_Entry *obj)
2466 if ((elm = objlist_find(list, obj)) != NULL) {
2467 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2473 * Relocate dag rooted in the specified object.
2474 * Returns 0 on success, or -1 on failure.
2478 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2479 int flags, RtldLockState *lockstate)
2485 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2486 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2495 * Relocate single object.
2496 * Returns 0 on success, or -1 on failure.
2499 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2500 int flags, RtldLockState *lockstate)
2505 obj->relocated = true;
2507 dbg("relocating \"%s\"", obj->path);
2509 if (obj->symtab == NULL || obj->strtab == NULL ||
2510 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2511 _rtld_error("%s: Shared object has no run-time symbol table",
2517 /* There are relocations to the write-protected text segment. */
2518 if (mprotect(obj->mapbase, obj->textsize,
2519 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2520 _rtld_error("%s: Cannot write-enable text segment: %s",
2521 obj->path, rtld_strerror(errno));
2526 /* Process the non-PLT non-IFUNC relocations. */
2527 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2530 if (obj->textrel) { /* Re-protected the text segment. */
2531 if (mprotect(obj->mapbase, obj->textsize,
2532 PROT_READ|PROT_EXEC) == -1) {
2533 _rtld_error("%s: Cannot write-protect text segment: %s",
2534 obj->path, rtld_strerror(errno));
2539 /* Set the special PLT or GOT entries. */
2542 /* Process the PLT relocations. */
2543 if (reloc_plt(obj) == -1)
2545 /* Relocate the jump slots if we are doing immediate binding. */
2546 if (obj->bind_now || bind_now)
2547 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2551 * Process the non-PLT IFUNC relocations. The relocations are
2552 * processed in two phases, because IFUNC resolvers may
2553 * reference other symbols, which must be readily processed
2554 * before resolvers are called.
2556 if (obj->non_plt_gnu_ifunc &&
2557 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2560 if (obj->relro_size > 0) {
2561 if (mprotect(obj->relro_page, obj->relro_size,
2563 _rtld_error("%s: Cannot enforce relro protection: %s",
2564 obj->path, rtld_strerror(errno));
2570 * Set up the magic number and version in the Obj_Entry. These
2571 * were checked in the crt1.o from the original ElfKit, so we
2572 * set them for backward compatibility.
2574 obj->magic = RTLD_MAGIC;
2575 obj->version = RTLD_VERSION;
2581 * Relocate newly-loaded shared objects. The argument is a pointer to
2582 * the Obj_Entry for the first such object. All objects from the first
2583 * to the end of the list of objects are relocated. Returns 0 on success,
2587 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2588 int flags, RtldLockState *lockstate)
2593 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2594 error = relocate_object(obj, bind_now, rtldobj, flags,
2603 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2604 * referencing STT_GNU_IFUNC symbols is postponed till the other
2605 * relocations are done. The indirect functions specified as
2606 * ifunc are allowed to call other symbols, so we need to have
2607 * objects relocated before asking for resolution from indirects.
2609 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2610 * instead of the usual lazy handling of PLT slots. It is
2611 * consistent with how GNU does it.
2614 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2615 RtldLockState *lockstate)
2617 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2619 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2620 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2626 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2627 RtldLockState *lockstate)
2631 for (obj = first; obj != NULL; obj = obj->next) {
2632 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2639 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2640 RtldLockState *lockstate)
2644 STAILQ_FOREACH(elm, list, link) {
2645 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2653 * Cleanup procedure. It will be called (by the atexit mechanism) just
2654 * before the process exits.
2659 RtldLockState lockstate;
2661 wlock_acquire(rtld_bind_lock, &lockstate);
2663 objlist_call_fini(&list_fini, NULL, &lockstate);
2664 /* No need to remove the items from the list, since we are exiting. */
2665 if (!libmap_disable)
2667 lock_release(rtld_bind_lock, &lockstate);
2671 * Iterate over a search path, translate each element, and invoke the
2672 * callback on the result.
2675 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2681 path += strspn(path, ":;");
2682 while (*path != '\0') {
2686 len = strcspn(path, ":;");
2687 trans = lm_findn(NULL, path, len);
2689 res = callback(trans, strlen(trans), arg);
2691 res = callback(path, len, arg);
2697 path += strspn(path, ":;");
2703 struct try_library_args {
2711 try_library_path(const char *dir, size_t dirlen, void *param)
2713 struct try_library_args *arg;
2716 if (*dir == '/' || trust) {
2719 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2722 pathname = arg->buffer;
2723 strncpy(pathname, dir, dirlen);
2724 pathname[dirlen] = '/';
2725 strcpy(pathname + dirlen + 1, arg->name);
2727 dbg(" Trying \"%s\"", pathname);
2728 if (access(pathname, F_OK) == 0) { /* We found it */
2729 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2730 strcpy(pathname, arg->buffer);
2738 search_library_path(const char *name, const char *path)
2741 struct try_library_args arg;
2747 arg.namelen = strlen(name);
2748 arg.buffer = xmalloc(PATH_MAX);
2749 arg.buflen = PATH_MAX;
2751 p = path_enumerate(path, try_library_path, &arg);
2759 dlclose(void *handle)
2762 RtldLockState lockstate;
2764 wlock_acquire(rtld_bind_lock, &lockstate);
2765 root = dlcheck(handle);
2767 lock_release(rtld_bind_lock, &lockstate);
2770 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2773 /* Unreference the object and its dependencies. */
2774 root->dl_refcount--;
2776 if (root->refcount == 1) {
2778 * The object will be no longer referenced, so we must unload it.
2779 * First, call the fini functions.
2781 objlist_call_fini(&list_fini, root, &lockstate);
2785 /* Finish cleaning up the newly-unreferenced objects. */
2786 GDB_STATE(RT_DELETE,&root->linkmap);
2787 unload_object(root);
2788 GDB_STATE(RT_CONSISTENT,NULL);
2792 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2793 lock_release(rtld_bind_lock, &lockstate);
2800 char *msg = error_message;
2801 error_message = NULL;
2806 * This function is deprecated and has no effect.
2809 dllockinit(void *context,
2810 void *(*lock_create)(void *context),
2811 void (*rlock_acquire)(void *lock),
2812 void (*wlock_acquire)(void *lock),
2813 void (*lock_release)(void *lock),
2814 void (*lock_destroy)(void *lock),
2815 void (*context_destroy)(void *context))
2817 static void *cur_context;
2818 static void (*cur_context_destroy)(void *);
2820 /* Just destroy the context from the previous call, if necessary. */
2821 if (cur_context_destroy != NULL)
2822 cur_context_destroy(cur_context);
2823 cur_context = context;
2824 cur_context_destroy = context_destroy;
2828 dlopen(const char *name, int mode)
2831 return (rtld_dlopen(name, -1, mode));
2835 fdlopen(int fd, int mode)
2838 return (rtld_dlopen(NULL, fd, mode));
2842 rtld_dlopen(const char *name, int fd, int mode)
2844 RtldLockState lockstate;
2847 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2848 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2849 if (ld_tracing != NULL) {
2850 rlock_acquire(rtld_bind_lock, &lockstate);
2851 if (sigsetjmp(lockstate.env, 0) != 0)
2852 lock_upgrade(rtld_bind_lock, &lockstate);
2853 environ = (char **)*get_program_var_addr("environ", &lockstate);
2854 lock_release(rtld_bind_lock, &lockstate);
2856 lo_flags = RTLD_LO_DLOPEN;
2857 if (mode & RTLD_NODELETE)
2858 lo_flags |= RTLD_LO_NODELETE;
2859 if (mode & RTLD_NOLOAD)
2860 lo_flags |= RTLD_LO_NOLOAD;
2861 if (ld_tracing != NULL)
2862 lo_flags |= RTLD_LO_TRACE;
2864 return (dlopen_object(name, fd, obj_main, lo_flags,
2865 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2869 dlopen_cleanup(Obj_Entry *obj)
2874 if (obj->refcount == 0)
2879 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2880 int mode, RtldLockState *lockstate)
2882 Obj_Entry **old_obj_tail;
2885 RtldLockState mlockstate;
2888 objlist_init(&initlist);
2890 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2891 wlock_acquire(rtld_bind_lock, &mlockstate);
2892 lockstate = &mlockstate;
2894 GDB_STATE(RT_ADD,NULL);
2896 old_obj_tail = obj_tail;
2898 if (name == NULL && fd == -1) {
2902 obj = load_object(name, fd, refobj, lo_flags);
2907 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2908 objlist_push_tail(&list_global, obj);
2909 if (*old_obj_tail != NULL) { /* We loaded something new. */
2910 assert(*old_obj_tail == obj);
2911 result = load_needed_objects(obj,
2912 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2916 result = rtld_verify_versions(&obj->dagmembers);
2917 if (result != -1 && ld_tracing)
2919 if (result == -1 || relocate_object_dag(obj,
2920 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2921 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2923 dlopen_cleanup(obj);
2925 } else if (lo_flags & RTLD_LO_EARLY) {
2927 * Do not call the init functions for early loaded
2928 * filtees. The image is still not initialized enough
2931 * Our object is found by the global object list and
2932 * will be ordered among all init calls done right
2933 * before transferring control to main.
2936 /* Make list of init functions to call. */
2937 initlist_add_objects(obj, &obj->next, &initlist);
2940 * Process all no_delete objects here, given them own
2941 * DAGs to prevent their dependencies from being unloaded.
2942 * This has to be done after we have loaded all of the
2943 * dependencies, so that we do not miss any.
2946 process_nodelete(obj);
2949 * Bump the reference counts for objects on this DAG. If
2950 * this is the first dlopen() call for the object that was
2951 * already loaded as a dependency, initialize the dag
2957 if ((lo_flags & RTLD_LO_TRACE) != 0)
2960 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2961 obj->z_nodelete) && !obj->ref_nodel) {
2962 dbg("obj %s nodelete", obj->path);
2964 obj->z_nodelete = obj->ref_nodel = true;
2968 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2970 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2972 if (!(lo_flags & RTLD_LO_EARLY)) {
2973 map_stacks_exec(lockstate);
2976 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2977 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2979 objlist_clear(&initlist);
2980 dlopen_cleanup(obj);
2981 if (lockstate == &mlockstate)
2982 lock_release(rtld_bind_lock, lockstate);
2986 if (!(lo_flags & RTLD_LO_EARLY)) {
2987 /* Call the init functions. */
2988 objlist_call_init(&initlist, lockstate);
2990 objlist_clear(&initlist);
2991 if (lockstate == &mlockstate)
2992 lock_release(rtld_bind_lock, lockstate);
2995 trace_loaded_objects(obj);
2996 if (lockstate == &mlockstate)
2997 lock_release(rtld_bind_lock, lockstate);
3002 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3006 const Obj_Entry *obj, *defobj;
3009 RtldLockState lockstate;
3017 symlook_init(&req, name);
3019 req.flags = flags | SYMLOOK_IN_PLT;
3020 req.lockstate = &lockstate;
3022 rlock_acquire(rtld_bind_lock, &lockstate);
3023 if (sigsetjmp(lockstate.env, 0) != 0)
3024 lock_upgrade(rtld_bind_lock, &lockstate);
3025 if (handle == NULL || handle == RTLD_NEXT ||
3026 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3028 if ((obj = obj_from_addr(retaddr)) == NULL) {
3029 _rtld_error("Cannot determine caller's shared object");
3030 lock_release(rtld_bind_lock, &lockstate);
3033 if (handle == NULL) { /* Just the caller's shared object. */
3034 res = symlook_obj(&req, obj);
3037 defobj = req.defobj_out;
3039 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3040 handle == RTLD_SELF) { /* ... caller included */
3041 if (handle == RTLD_NEXT)
3043 for (; obj != NULL; obj = obj->next) {
3044 res = symlook_obj(&req, obj);
3047 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3049 defobj = req.defobj_out;
3050 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3056 * Search the dynamic linker itself, and possibly resolve the
3057 * symbol from there. This is how the application links to
3058 * dynamic linker services such as dlopen.
3060 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3061 res = symlook_obj(&req, &obj_rtld);
3064 defobj = req.defobj_out;
3068 assert(handle == RTLD_DEFAULT);
3069 res = symlook_default(&req, obj);
3071 defobj = req.defobj_out;
3076 if ((obj = dlcheck(handle)) == NULL) {
3077 lock_release(rtld_bind_lock, &lockstate);
3081 donelist_init(&donelist);
3082 if (obj->mainprog) {
3083 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3084 res = symlook_global(&req, &donelist);
3087 defobj = req.defobj_out;
3090 * Search the dynamic linker itself, and possibly resolve the
3091 * symbol from there. This is how the application links to
3092 * dynamic linker services such as dlopen.
3094 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3095 res = symlook_obj(&req, &obj_rtld);
3098 defobj = req.defobj_out;
3103 /* Search the whole DAG rooted at the given object. */
3104 res = symlook_list(&req, &obj->dagmembers, &donelist);
3107 defobj = req.defobj_out;
3113 lock_release(rtld_bind_lock, &lockstate);
3116 * The value required by the caller is derived from the value
3117 * of the symbol. For the ia64 architecture, we need to
3118 * construct a function descriptor which the caller can use to
3119 * call the function with the right 'gp' value. For other
3120 * architectures and for non-functions, the value is simply
3121 * the relocated value of the symbol.
3123 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3124 return (make_function_pointer(def, defobj));
3125 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3126 return (rtld_resolve_ifunc(defobj, def));
3127 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3129 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3131 ti.ti_module = defobj->tlsindex;
3132 ti.ti_offset = def->st_value;
3133 return (__tls_get_addr(&ti));
3136 return (defobj->relocbase + def->st_value);
3139 _rtld_error("Undefined symbol \"%s\"", name);
3140 lock_release(rtld_bind_lock, &lockstate);
3145 dlsym(void *handle, const char *name)
3147 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3152 dlfunc(void *handle, const char *name)
3159 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3165 dlvsym(void *handle, const char *name, const char *version)
3169 ventry.name = version;
3171 ventry.hash = elf_hash(version);
3173 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3178 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3180 const Obj_Entry *obj;
3181 RtldLockState lockstate;
3183 rlock_acquire(rtld_bind_lock, &lockstate);
3184 obj = obj_from_addr(addr);
3186 _rtld_error("No shared object contains address");
3187 lock_release(rtld_bind_lock, &lockstate);
3190 rtld_fill_dl_phdr_info(obj, phdr_info);
3191 lock_release(rtld_bind_lock, &lockstate);
3196 dladdr(const void *addr, Dl_info *info)
3198 const Obj_Entry *obj;
3201 unsigned long symoffset;
3202 RtldLockState lockstate;
3204 rlock_acquire(rtld_bind_lock, &lockstate);
3205 obj = obj_from_addr(addr);
3207 _rtld_error("No shared object contains address");
3208 lock_release(rtld_bind_lock, &lockstate);
3211 info->dli_fname = obj->path;
3212 info->dli_fbase = obj->mapbase;
3213 info->dli_saddr = (void *)0;
3214 info->dli_sname = NULL;
3217 * Walk the symbol list looking for the symbol whose address is
3218 * closest to the address sent in.
3220 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3221 def = obj->symtab + symoffset;
3224 * For skip the symbol if st_shndx is either SHN_UNDEF or
3227 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3231 * If the symbol is greater than the specified address, or if it
3232 * is further away from addr than the current nearest symbol,
3235 symbol_addr = obj->relocbase + def->st_value;
3236 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3239 /* Update our idea of the nearest symbol. */
3240 info->dli_sname = obj->strtab + def->st_name;
3241 info->dli_saddr = symbol_addr;
3244 if (info->dli_saddr == addr)
3247 lock_release(rtld_bind_lock, &lockstate);
3252 dlinfo(void *handle, int request, void *p)
3254 const Obj_Entry *obj;
3255 RtldLockState lockstate;
3258 rlock_acquire(rtld_bind_lock, &lockstate);
3260 if (handle == NULL || handle == RTLD_SELF) {
3263 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3264 if ((obj = obj_from_addr(retaddr)) == NULL)
3265 _rtld_error("Cannot determine caller's shared object");
3267 obj = dlcheck(handle);
3270 lock_release(rtld_bind_lock, &lockstate);
3276 case RTLD_DI_LINKMAP:
3277 *((struct link_map const **)p) = &obj->linkmap;
3279 case RTLD_DI_ORIGIN:
3280 error = rtld_dirname(obj->path, p);
3283 case RTLD_DI_SERINFOSIZE:
3284 case RTLD_DI_SERINFO:
3285 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3289 _rtld_error("Invalid request %d passed to dlinfo()", request);
3293 lock_release(rtld_bind_lock, &lockstate);
3299 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3302 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3303 phdr_info->dlpi_name = obj->path;
3304 phdr_info->dlpi_phdr = obj->phdr;
3305 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3306 phdr_info->dlpi_tls_modid = obj->tlsindex;
3307 phdr_info->dlpi_tls_data = obj->tlsinit;
3308 phdr_info->dlpi_adds = obj_loads;
3309 phdr_info->dlpi_subs = obj_loads - obj_count;
3313 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3315 struct dl_phdr_info phdr_info;
3316 const Obj_Entry *obj;
3317 RtldLockState bind_lockstate, phdr_lockstate;
3320 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3321 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3325 for (obj = obj_list; obj != NULL; obj = obj->next) {
3326 rtld_fill_dl_phdr_info(obj, &phdr_info);
3327 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3331 lock_release(rtld_bind_lock, &bind_lockstate);
3332 lock_release(rtld_phdr_lock, &phdr_lockstate);
3338 fill_search_info(const char *dir, size_t dirlen, void *param)
3340 struct fill_search_info_args *arg;
3344 if (arg->request == RTLD_DI_SERINFOSIZE) {
3345 arg->serinfo->dls_cnt ++;
3346 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3348 struct dl_serpath *s_entry;
3350 s_entry = arg->serpath;
3351 s_entry->dls_name = arg->strspace;
3352 s_entry->dls_flags = arg->flags;
3354 strncpy(arg->strspace, dir, dirlen);
3355 arg->strspace[dirlen] = '\0';
3357 arg->strspace += dirlen + 1;
3365 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3367 struct dl_serinfo _info;
3368 struct fill_search_info_args args;
3370 args.request = RTLD_DI_SERINFOSIZE;
3371 args.serinfo = &_info;
3373 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3376 path_enumerate(obj->rpath, fill_search_info, &args);
3377 path_enumerate(ld_library_path, fill_search_info, &args);
3378 path_enumerate(obj->runpath, fill_search_info, &args);
3379 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3380 if (!obj->z_nodeflib)
3381 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3384 if (request == RTLD_DI_SERINFOSIZE) {
3385 info->dls_size = _info.dls_size;
3386 info->dls_cnt = _info.dls_cnt;
3390 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3391 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3395 args.request = RTLD_DI_SERINFO;
3396 args.serinfo = info;
3397 args.serpath = &info->dls_serpath[0];
3398 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3400 args.flags = LA_SER_RUNPATH;
3401 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3404 args.flags = LA_SER_LIBPATH;
3405 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3408 args.flags = LA_SER_RUNPATH;
3409 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3412 args.flags = LA_SER_CONFIG;
3413 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3417 args.flags = LA_SER_DEFAULT;
3418 if (!obj->z_nodeflib &&
3419 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3425 rtld_dirname(const char *path, char *bname)
3429 /* Empty or NULL string gets treated as "." */
3430 if (path == NULL || *path == '\0') {
3436 /* Strip trailing slashes */
3437 endp = path + strlen(path) - 1;
3438 while (endp > path && *endp == '/')
3441 /* Find the start of the dir */
3442 while (endp > path && *endp != '/')
3445 /* Either the dir is "/" or there are no slashes */
3447 bname[0] = *endp == '/' ? '/' : '.';
3453 } while (endp > path && *endp == '/');
3456 if (endp - path + 2 > PATH_MAX)
3458 _rtld_error("Filename is too long: %s", path);
3462 strncpy(bname, path, endp - path + 1);
3463 bname[endp - path + 1] = '\0';
3468 rtld_dirname_abs(const char *path, char *base)
3472 if (realpath(path, base) == NULL)
3474 dbg("%s -> %s", path, base);
3475 last = strrchr(base, '/');
3484 linkmap_add(Obj_Entry *obj)
3486 struct link_map *l = &obj->linkmap;
3487 struct link_map *prev;
3489 obj->linkmap.l_name = obj->path;
3490 obj->linkmap.l_addr = obj->mapbase;
3491 obj->linkmap.l_ld = obj->dynamic;
3493 /* GDB needs load offset on MIPS to use the symbols */
3494 obj->linkmap.l_offs = obj->relocbase;
3497 if (r_debug.r_map == NULL) {
3503 * Scan to the end of the list, but not past the entry for the
3504 * dynamic linker, which we want to keep at the very end.
3506 for (prev = r_debug.r_map;
3507 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3508 prev = prev->l_next)
3511 /* Link in the new entry. */
3513 l->l_next = prev->l_next;
3514 if (l->l_next != NULL)
3515 l->l_next->l_prev = l;
3520 linkmap_delete(Obj_Entry *obj)
3522 struct link_map *l = &obj->linkmap;
3524 if (l->l_prev == NULL) {
3525 if ((r_debug.r_map = l->l_next) != NULL)
3526 l->l_next->l_prev = NULL;
3530 if ((l->l_prev->l_next = l->l_next) != NULL)
3531 l->l_next->l_prev = l->l_prev;
3535 * Function for the debugger to set a breakpoint on to gain control.
3537 * The two parameters allow the debugger to easily find and determine
3538 * what the runtime loader is doing and to whom it is doing it.
3540 * When the loadhook trap is hit (r_debug_state, set at program
3541 * initialization), the arguments can be found on the stack:
3543 * +8 struct link_map *m
3544 * +4 struct r_debug *rd
3548 r_debug_state(struct r_debug* rd, struct link_map *m)
3551 * The following is a hack to force the compiler to emit calls to
3552 * this function, even when optimizing. If the function is empty,
3553 * the compiler is not obliged to emit any code for calls to it,
3554 * even when marked __noinline. However, gdb depends on those
3557 __compiler_membar();
3561 * A function called after init routines have completed. This can be used to
3562 * break before a program's entry routine is called, and can be used when
3563 * main is not available in the symbol table.
3566 _r_debug_postinit(struct link_map *m)
3569 /* See r_debug_state(). */
3570 __compiler_membar();
3574 * Get address of the pointer variable in the main program.
3575 * Prefer non-weak symbol over the weak one.
3577 static const void **
3578 get_program_var_addr(const char *name, RtldLockState *lockstate)
3583 symlook_init(&req, name);
3584 req.lockstate = lockstate;
3585 donelist_init(&donelist);
3586 if (symlook_global(&req, &donelist) != 0)
3588 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3589 return ((const void **)make_function_pointer(req.sym_out,
3591 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3592 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3594 return ((const void **)(req.defobj_out->relocbase +
3595 req.sym_out->st_value));
3599 * Set a pointer variable in the main program to the given value. This
3600 * is used to set key variables such as "environ" before any of the
3601 * init functions are called.
3604 set_program_var(const char *name, const void *value)
3608 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3609 dbg("\"%s\": *%p <-- %p", name, addr, value);
3615 * Search the global objects, including dependencies and main object,
3616 * for the given symbol.
3619 symlook_global(SymLook *req, DoneList *donelist)
3622 const Objlist_Entry *elm;
3625 symlook_init_from_req(&req1, req);
3627 /* Search all objects loaded at program start up. */
3628 if (req->defobj_out == NULL ||
3629 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3630 res = symlook_list(&req1, &list_main, donelist);
3631 if (res == 0 && (req->defobj_out == NULL ||
3632 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3633 req->sym_out = req1.sym_out;
3634 req->defobj_out = req1.defobj_out;
3635 assert(req->defobj_out != NULL);
3639 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3640 STAILQ_FOREACH(elm, &list_global, link) {
3641 if (req->defobj_out != NULL &&
3642 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3644 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3645 if (res == 0 && (req->defobj_out == NULL ||
3646 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3647 req->sym_out = req1.sym_out;
3648 req->defobj_out = req1.defobj_out;
3649 assert(req->defobj_out != NULL);
3653 return (req->sym_out != NULL ? 0 : ESRCH);
3657 * Given a symbol name in a referencing object, find the corresponding
3658 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3659 * no definition was found. Returns a pointer to the Obj_Entry of the
3660 * defining object via the reference parameter DEFOBJ_OUT.
3663 symlook_default(SymLook *req, const Obj_Entry *refobj)
3666 const Objlist_Entry *elm;
3670 donelist_init(&donelist);
3671 symlook_init_from_req(&req1, req);
3673 /* Look first in the referencing object if linked symbolically. */
3674 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3675 res = symlook_obj(&req1, refobj);
3677 req->sym_out = req1.sym_out;
3678 req->defobj_out = req1.defobj_out;
3679 assert(req->defobj_out != NULL);
3683 symlook_global(req, &donelist);
3685 /* Search all dlopened DAGs containing the referencing object. */
3686 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3687 if (req->sym_out != NULL &&
3688 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3690 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3691 if (res == 0 && (req->sym_out == NULL ||
3692 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3693 req->sym_out = req1.sym_out;
3694 req->defobj_out = req1.defobj_out;
3695 assert(req->defobj_out != NULL);
3700 * Search the dynamic linker itself, and possibly resolve the
3701 * symbol from there. This is how the application links to
3702 * dynamic linker services such as dlopen.
3704 if (req->sym_out == NULL ||
3705 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3706 res = symlook_obj(&req1, &obj_rtld);
3708 req->sym_out = req1.sym_out;
3709 req->defobj_out = req1.defobj_out;
3710 assert(req->defobj_out != NULL);
3714 return (req->sym_out != NULL ? 0 : ESRCH);
3718 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3721 const Obj_Entry *defobj;
3722 const Objlist_Entry *elm;
3728 STAILQ_FOREACH(elm, objlist, link) {
3729 if (donelist_check(dlp, elm->obj))
3731 symlook_init_from_req(&req1, req);
3732 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3733 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3735 defobj = req1.defobj_out;
3736 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3743 req->defobj_out = defobj;
3750 * Search the chain of DAGS cointed to by the given Needed_Entry
3751 * for a symbol of the given name. Each DAG is scanned completely
3752 * before advancing to the next one. Returns a pointer to the symbol,
3753 * or NULL if no definition was found.
3756 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3759 const Needed_Entry *n;
3760 const Obj_Entry *defobj;
3766 symlook_init_from_req(&req1, req);
3767 for (n = needed; n != NULL; n = n->next) {
3768 if (n->obj == NULL ||
3769 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3771 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3773 defobj = req1.defobj_out;
3774 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3780 req->defobj_out = defobj;
3787 * Search the symbol table of a single shared object for a symbol of
3788 * the given name and version, if requested. Returns a pointer to the
3789 * symbol, or NULL if no definition was found. If the object is
3790 * filter, return filtered symbol from filtee.
3792 * The symbol's hash value is passed in for efficiency reasons; that
3793 * eliminates many recomputations of the hash value.
3796 symlook_obj(SymLook *req, const Obj_Entry *obj)
3800 int flags, res, mres;
3803 * If there is at least one valid hash at this point, we prefer to
3804 * use the faster GNU version if available.
3806 if (obj->valid_hash_gnu)
3807 mres = symlook_obj1_gnu(req, obj);
3808 else if (obj->valid_hash_sysv)
3809 mres = symlook_obj1_sysv(req, obj);
3814 if (obj->needed_filtees != NULL) {
3815 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3816 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3817 donelist_init(&donelist);
3818 symlook_init_from_req(&req1, req);
3819 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3821 req->sym_out = req1.sym_out;
3822 req->defobj_out = req1.defobj_out;
3826 if (obj->needed_aux_filtees != NULL) {
3827 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3828 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3829 donelist_init(&donelist);
3830 symlook_init_from_req(&req1, req);
3831 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3833 req->sym_out = req1.sym_out;
3834 req->defobj_out = req1.defobj_out;
3842 /* Symbol match routine common to both hash functions */
3844 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3845 const unsigned long symnum)
3848 const Elf_Sym *symp;
3851 symp = obj->symtab + symnum;
3852 strp = obj->strtab + symp->st_name;
3854 switch (ELF_ST_TYPE(symp->st_info)) {
3860 if (symp->st_value == 0)
3864 if (symp->st_shndx != SHN_UNDEF)
3867 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3868 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3875 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3878 if (req->ventry == NULL) {
3879 if (obj->versyms != NULL) {
3880 verndx = VER_NDX(obj->versyms[symnum]);
3881 if (verndx > obj->vernum) {
3883 "%s: symbol %s references wrong version %d",
3884 obj->path, obj->strtab + symnum, verndx);
3888 * If we are not called from dlsym (i.e. this
3889 * is a normal relocation from unversioned
3890 * binary), accept the symbol immediately if
3891 * it happens to have first version after this
3892 * shared object became versioned. Otherwise,
3893 * if symbol is versioned and not hidden,
3894 * remember it. If it is the only symbol with
3895 * this name exported by the shared object, it
3896 * will be returned as a match by the calling
3897 * function. If symbol is global (verndx < 2)
3898 * accept it unconditionally.
3900 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3901 verndx == VER_NDX_GIVEN) {
3902 result->sym_out = symp;
3905 else if (verndx >= VER_NDX_GIVEN) {
3906 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3908 if (result->vsymp == NULL)
3909 result->vsymp = symp;
3915 result->sym_out = symp;
3918 if (obj->versyms == NULL) {
3919 if (object_match_name(obj, req->ventry->name)) {
3920 _rtld_error("%s: object %s should provide version %s "
3921 "for symbol %s", obj_rtld.path, obj->path,
3922 req->ventry->name, obj->strtab + symnum);
3926 verndx = VER_NDX(obj->versyms[symnum]);
3927 if (verndx > obj->vernum) {
3928 _rtld_error("%s: symbol %s references wrong version %d",
3929 obj->path, obj->strtab + symnum, verndx);
3932 if (obj->vertab[verndx].hash != req->ventry->hash ||
3933 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3935 * Version does not match. Look if this is a
3936 * global symbol and if it is not hidden. If
3937 * global symbol (verndx < 2) is available,
3938 * use it. Do not return symbol if we are
3939 * called by dlvsym, because dlvsym looks for
3940 * a specific version and default one is not
3941 * what dlvsym wants.
3943 if ((req->flags & SYMLOOK_DLSYM) ||
3944 (verndx >= VER_NDX_GIVEN) ||
3945 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3949 result->sym_out = symp;
3954 * Search for symbol using SysV hash function.
3955 * obj->buckets is known not to be NULL at this point; the test for this was
3956 * performed with the obj->valid_hash_sysv assignment.
3959 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
3961 unsigned long symnum;
3962 Sym_Match_Result matchres;
3964 matchres.sym_out = NULL;
3965 matchres.vsymp = NULL;
3966 matchres.vcount = 0;
3968 for (symnum = obj->buckets[req->hash % obj->nbuckets];
3969 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3970 if (symnum >= obj->nchains)
3971 return (ESRCH); /* Bad object */
3973 if (matched_symbol(req, obj, &matchres, symnum)) {
3974 req->sym_out = matchres.sym_out;
3975 req->defobj_out = obj;
3979 if (matchres.vcount == 1) {
3980 req->sym_out = matchres.vsymp;
3981 req->defobj_out = obj;
3987 /* Search for symbol using GNU hash function */
3989 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
3991 Elf_Addr bloom_word;
3992 const Elf32_Word *hashval;
3994 Sym_Match_Result matchres;
3995 unsigned int h1, h2;
3996 unsigned long symnum;
3998 matchres.sym_out = NULL;
3999 matchres.vsymp = NULL;
4000 matchres.vcount = 0;
4002 /* Pick right bitmask word from Bloom filter array */
4003 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4004 obj->maskwords_bm_gnu];
4006 /* Calculate modulus word size of gnu hash and its derivative */
4007 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4008 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4010 /* Filter out the "definitely not in set" queries */
4011 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4014 /* Locate hash chain and corresponding value element*/
4015 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4018 hashval = &obj->chain_zero_gnu[bucket];
4020 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4021 symnum = hashval - obj->chain_zero_gnu;
4022 if (matched_symbol(req, obj, &matchres, symnum)) {
4023 req->sym_out = matchres.sym_out;
4024 req->defobj_out = obj;
4028 } while ((*hashval++ & 1) == 0);
4029 if (matchres.vcount == 1) {
4030 req->sym_out = matchres.vsymp;
4031 req->defobj_out = obj;
4038 trace_loaded_objects(Obj_Entry *obj)
4040 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4043 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4046 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4047 fmt1 = "\t%o => %p (%x)\n";
4049 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4050 fmt2 = "\t%o (%x)\n";
4052 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4054 for (; obj; obj = obj->next) {
4055 Needed_Entry *needed;
4059 if (list_containers && obj->needed != NULL)
4060 rtld_printf("%s:\n", obj->path);
4061 for (needed = obj->needed; needed; needed = needed->next) {
4062 if (needed->obj != NULL) {
4063 if (needed->obj->traced && !list_containers)
4065 needed->obj->traced = true;
4066 path = needed->obj->path;
4070 name = (char *)obj->strtab + needed->name;
4071 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4073 fmt = is_lib ? fmt1 : fmt2;
4074 while ((c = *fmt++) != '\0') {
4100 rtld_putstr(main_local);
4103 rtld_putstr(obj_main->path);
4110 rtld_printf("%d", sodp->sod_major);
4113 rtld_printf("%d", sodp->sod_minor);
4120 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4133 * Unload a dlopened object and its dependencies from memory and from
4134 * our data structures. It is assumed that the DAG rooted in the
4135 * object has already been unreferenced, and that the object has a
4136 * reference count of 0.
4139 unload_object(Obj_Entry *root)
4144 assert(root->refcount == 0);
4147 * Pass over the DAG removing unreferenced objects from
4148 * appropriate lists.
4150 unlink_object(root);
4152 /* Unmap all objects that are no longer referenced. */
4153 linkp = &obj_list->next;
4154 while ((obj = *linkp) != NULL) {
4155 if (obj->refcount == 0) {
4156 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4158 dbg("unloading \"%s\"", obj->path);
4159 unload_filtees(root);
4160 munmap(obj->mapbase, obj->mapsize);
4161 linkmap_delete(obj);
4172 unlink_object(Obj_Entry *root)
4176 if (root->refcount == 0) {
4177 /* Remove the object from the RTLD_GLOBAL list. */
4178 objlist_remove(&list_global, root);
4180 /* Remove the object from all objects' DAG lists. */
4181 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4182 objlist_remove(&elm->obj->dldags, root);
4183 if (elm->obj != root)
4184 unlink_object(elm->obj);
4190 ref_dag(Obj_Entry *root)
4194 assert(root->dag_inited);
4195 STAILQ_FOREACH(elm, &root->dagmembers, link)
4196 elm->obj->refcount++;
4200 unref_dag(Obj_Entry *root)
4204 assert(root->dag_inited);
4205 STAILQ_FOREACH(elm, &root->dagmembers, link)
4206 elm->obj->refcount--;
4210 * Common code for MD __tls_get_addr().
4212 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4214 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4216 Elf_Addr *newdtv, *dtv;
4217 RtldLockState lockstate;
4221 /* Check dtv generation in case new modules have arrived */
4222 if (dtv[0] != tls_dtv_generation) {
4223 wlock_acquire(rtld_bind_lock, &lockstate);
4224 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4226 if (to_copy > tls_max_index)
4227 to_copy = tls_max_index;
4228 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4229 newdtv[0] = tls_dtv_generation;
4230 newdtv[1] = tls_max_index;
4232 lock_release(rtld_bind_lock, &lockstate);
4233 dtv = *dtvp = newdtv;
4236 /* Dynamically allocate module TLS if necessary */
4237 if (dtv[index + 1] == 0) {
4238 /* Signal safe, wlock will block out signals. */
4239 wlock_acquire(rtld_bind_lock, &lockstate);
4240 if (!dtv[index + 1])
4241 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4242 lock_release(rtld_bind_lock, &lockstate);
4244 return ((void *)(dtv[index + 1] + offset));
4248 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4253 /* Check dtv generation in case new modules have arrived */
4254 if (__predict_true(dtv[0] == tls_dtv_generation &&
4255 dtv[index + 1] != 0))
4256 return ((void *)(dtv[index + 1] + offset));
4257 return (tls_get_addr_slow(dtvp, index, offset));
4260 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__)
4263 * Allocate Static TLS using the Variant I method.
4266 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4275 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4278 assert(tcbsize >= TLS_TCB_SIZE);
4279 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4280 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4282 if (oldtcb != NULL) {
4283 memcpy(tls, oldtcb, tls_static_space);
4286 /* Adjust the DTV. */
4288 for (i = 0; i < dtv[1]; i++) {
4289 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4290 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4291 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4295 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4297 dtv[0] = tls_dtv_generation;
4298 dtv[1] = tls_max_index;
4300 for (obj = objs; obj; obj = obj->next) {
4301 if (obj->tlsoffset > 0) {
4302 addr = (Elf_Addr)tls + obj->tlsoffset;
4303 if (obj->tlsinitsize > 0)
4304 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4305 if (obj->tlssize > obj->tlsinitsize)
4306 memset((void*) (addr + obj->tlsinitsize), 0,
4307 obj->tlssize - obj->tlsinitsize);
4308 dtv[obj->tlsindex + 1] = addr;
4317 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4320 Elf_Addr tlsstart, tlsend;
4323 assert(tcbsize >= TLS_TCB_SIZE);
4325 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4326 tlsend = tlsstart + tls_static_space;
4328 dtv = *(Elf_Addr **)tlsstart;
4330 for (i = 0; i < dtvsize; i++) {
4331 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4332 free((void*)dtv[i+2]);
4341 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4344 * Allocate Static TLS using the Variant II method.
4347 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4350 size_t size, ralign;
4352 Elf_Addr *dtv, *olddtv;
4353 Elf_Addr segbase, oldsegbase, addr;
4357 if (tls_static_max_align > ralign)
4358 ralign = tls_static_max_align;
4359 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4361 assert(tcbsize >= 2*sizeof(Elf_Addr));
4362 tls = malloc_aligned(size, ralign);
4363 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4365 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4366 ((Elf_Addr*)segbase)[0] = segbase;
4367 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4369 dtv[0] = tls_dtv_generation;
4370 dtv[1] = tls_max_index;
4374 * Copy the static TLS block over whole.
4376 oldsegbase = (Elf_Addr) oldtls;
4377 memcpy((void *)(segbase - tls_static_space),
4378 (const void *)(oldsegbase - tls_static_space),
4382 * If any dynamic TLS blocks have been created tls_get_addr(),
4385 olddtv = ((Elf_Addr**)oldsegbase)[1];
4386 for (i = 0; i < olddtv[1]; i++) {
4387 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4388 dtv[i+2] = olddtv[i+2];
4394 * We assume that this block was the one we created with
4395 * allocate_initial_tls().
4397 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4399 for (obj = objs; obj; obj = obj->next) {
4400 if (obj->tlsoffset) {
4401 addr = segbase - obj->tlsoffset;
4402 memset((void*) (addr + obj->tlsinitsize),
4403 0, obj->tlssize - obj->tlsinitsize);
4405 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4406 dtv[obj->tlsindex + 1] = addr;
4411 return (void*) segbase;
4415 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4418 size_t size, ralign;
4420 Elf_Addr tlsstart, tlsend;
4423 * Figure out the size of the initial TLS block so that we can
4424 * find stuff which ___tls_get_addr() allocated dynamically.
4427 if (tls_static_max_align > ralign)
4428 ralign = tls_static_max_align;
4429 size = round(tls_static_space, ralign);
4431 dtv = ((Elf_Addr**)tls)[1];
4433 tlsend = (Elf_Addr) tls;
4434 tlsstart = tlsend - size;
4435 for (i = 0; i < dtvsize; i++) {
4436 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4437 free_aligned((void *)dtv[i + 2]);
4441 free_aligned((void *)tlsstart);
4448 * Allocate TLS block for module with given index.
4451 allocate_module_tls(int index)
4456 for (obj = obj_list; obj; obj = obj->next) {
4457 if (obj->tlsindex == index)
4461 _rtld_error("Can't find module with TLS index %d", index);
4465 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4466 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4467 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4473 allocate_tls_offset(Obj_Entry *obj)
4480 if (obj->tlssize == 0) {
4481 obj->tls_done = true;
4485 if (obj->tlsindex == 1)
4486 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4488 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4489 obj->tlssize, obj->tlsalign);
4492 * If we have already fixed the size of the static TLS block, we
4493 * must stay within that size. When allocating the static TLS, we
4494 * leave a small amount of space spare to be used for dynamically
4495 * loading modules which use static TLS.
4497 if (tls_static_space != 0) {
4498 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4500 } else if (obj->tlsalign > tls_static_max_align) {
4501 tls_static_max_align = obj->tlsalign;
4504 tls_last_offset = obj->tlsoffset = off;
4505 tls_last_size = obj->tlssize;
4506 obj->tls_done = true;
4512 free_tls_offset(Obj_Entry *obj)
4516 * If we were the last thing to allocate out of the static TLS
4517 * block, we give our space back to the 'allocator'. This is a
4518 * simplistic workaround to allow libGL.so.1 to be loaded and
4519 * unloaded multiple times.
4521 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4522 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4523 tls_last_offset -= obj->tlssize;
4529 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4532 RtldLockState lockstate;
4534 wlock_acquire(rtld_bind_lock, &lockstate);
4535 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
4536 lock_release(rtld_bind_lock, &lockstate);
4541 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4543 RtldLockState lockstate;
4545 wlock_acquire(rtld_bind_lock, &lockstate);
4546 free_tls(tcb, tcbsize, tcbalign);
4547 lock_release(rtld_bind_lock, &lockstate);
4551 object_add_name(Obj_Entry *obj, const char *name)
4557 entry = malloc(sizeof(Name_Entry) + len);
4559 if (entry != NULL) {
4560 strcpy(entry->name, name);
4561 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4566 object_match_name(const Obj_Entry *obj, const char *name)
4570 STAILQ_FOREACH(entry, &obj->names, link) {
4571 if (strcmp(name, entry->name) == 0)
4578 locate_dependency(const Obj_Entry *obj, const char *name)
4580 const Objlist_Entry *entry;
4581 const Needed_Entry *needed;
4583 STAILQ_FOREACH(entry, &list_main, link) {
4584 if (object_match_name(entry->obj, name))
4588 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4589 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4590 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4592 * If there is DT_NEEDED for the name we are looking for,
4593 * we are all set. Note that object might not be found if
4594 * dependency was not loaded yet, so the function can
4595 * return NULL here. This is expected and handled
4596 * properly by the caller.
4598 return (needed->obj);
4601 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4607 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4608 const Elf_Vernaux *vna)
4610 const Elf_Verdef *vd;
4611 const char *vername;
4613 vername = refobj->strtab + vna->vna_name;
4614 vd = depobj->verdef;
4616 _rtld_error("%s: version %s required by %s not defined",
4617 depobj->path, vername, refobj->path);
4621 if (vd->vd_version != VER_DEF_CURRENT) {
4622 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4623 depobj->path, vd->vd_version);
4626 if (vna->vna_hash == vd->vd_hash) {
4627 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4628 ((char *)vd + vd->vd_aux);
4629 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4632 if (vd->vd_next == 0)
4634 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4636 if (vna->vna_flags & VER_FLG_WEAK)
4638 _rtld_error("%s: version %s required by %s not found",
4639 depobj->path, vername, refobj->path);
4644 rtld_verify_object_versions(Obj_Entry *obj)
4646 const Elf_Verneed *vn;
4647 const Elf_Verdef *vd;
4648 const Elf_Verdaux *vda;
4649 const Elf_Vernaux *vna;
4650 const Obj_Entry *depobj;
4651 int maxvernum, vernum;
4653 if (obj->ver_checked)
4655 obj->ver_checked = true;
4659 * Walk over defined and required version records and figure out
4660 * max index used by any of them. Do very basic sanity checking
4664 while (vn != NULL) {
4665 if (vn->vn_version != VER_NEED_CURRENT) {
4666 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4667 obj->path, vn->vn_version);
4670 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4672 vernum = VER_NEED_IDX(vna->vna_other);
4673 if (vernum > maxvernum)
4675 if (vna->vna_next == 0)
4677 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4679 if (vn->vn_next == 0)
4681 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4685 while (vd != NULL) {
4686 if (vd->vd_version != VER_DEF_CURRENT) {
4687 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4688 obj->path, vd->vd_version);
4691 vernum = VER_DEF_IDX(vd->vd_ndx);
4692 if (vernum > maxvernum)
4694 if (vd->vd_next == 0)
4696 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4703 * Store version information in array indexable by version index.
4704 * Verify that object version requirements are satisfied along the
4707 obj->vernum = maxvernum + 1;
4708 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4711 while (vd != NULL) {
4712 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4713 vernum = VER_DEF_IDX(vd->vd_ndx);
4714 assert(vernum <= maxvernum);
4715 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4716 obj->vertab[vernum].hash = vd->vd_hash;
4717 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4718 obj->vertab[vernum].file = NULL;
4719 obj->vertab[vernum].flags = 0;
4721 if (vd->vd_next == 0)
4723 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4727 while (vn != NULL) {
4728 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4731 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4733 if (check_object_provided_version(obj, depobj, vna))
4735 vernum = VER_NEED_IDX(vna->vna_other);
4736 assert(vernum <= maxvernum);
4737 obj->vertab[vernum].hash = vna->vna_hash;
4738 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4739 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4740 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4741 VER_INFO_HIDDEN : 0;
4742 if (vna->vna_next == 0)
4744 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4746 if (vn->vn_next == 0)
4748 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4754 rtld_verify_versions(const Objlist *objlist)
4756 Objlist_Entry *entry;
4760 STAILQ_FOREACH(entry, objlist, link) {
4762 * Skip dummy objects or objects that have their version requirements
4765 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4767 if (rtld_verify_object_versions(entry->obj) == -1) {
4769 if (ld_tracing == NULL)
4773 if (rc == 0 || ld_tracing != NULL)
4774 rc = rtld_verify_object_versions(&obj_rtld);
4779 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4784 vernum = VER_NDX(obj->versyms[symnum]);
4785 if (vernum >= obj->vernum) {
4786 _rtld_error("%s: symbol %s has wrong verneed value %d",
4787 obj->path, obj->strtab + symnum, vernum);
4788 } else if (obj->vertab[vernum].hash != 0) {
4789 return &obj->vertab[vernum];
4796 _rtld_get_stack_prot(void)
4799 return (stack_prot);
4803 _rtld_is_dlopened(void *arg)
4806 RtldLockState lockstate;
4809 rlock_acquire(rtld_bind_lock, &lockstate);
4812 obj = obj_from_addr(arg);
4814 _rtld_error("No shared object contains address");
4815 lock_release(rtld_bind_lock, &lockstate);
4818 res = obj->dlopened ? 1 : 0;
4819 lock_release(rtld_bind_lock, &lockstate);
4824 map_stacks_exec(RtldLockState *lockstate)
4826 void (*thr_map_stacks_exec)(void);
4828 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4830 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4831 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4832 if (thr_map_stacks_exec != NULL) {
4833 stack_prot |= PROT_EXEC;
4834 thr_map_stacks_exec();
4839 symlook_init(SymLook *dst, const char *name)
4842 bzero(dst, sizeof(*dst));
4844 dst->hash = elf_hash(name);
4845 dst->hash_gnu = gnu_hash(name);
4849 symlook_init_from_req(SymLook *dst, const SymLook *src)
4852 dst->name = src->name;
4853 dst->hash = src->hash;
4854 dst->hash_gnu = src->hash_gnu;
4855 dst->ventry = src->ventry;
4856 dst->flags = src->flags;
4857 dst->defobj_out = NULL;
4858 dst->sym_out = NULL;
4859 dst->lockstate = src->lockstate;
4863 * Overrides for libc_pic-provided functions.
4867 __getosreldate(void)
4877 oid[1] = KERN_OSRELDATE;
4879 len = sizeof(osrel);
4880 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4881 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4893 void (*__cleanup)(void);
4894 int __isthreaded = 0;
4895 int _thread_autoinit_dummy_decl = 1;
4898 * No unresolved symbols for rtld.
4901 __pthread_cxa_finalize(struct dl_phdr_info *a)
4906 __stack_chk_fail(void)
4909 _rtld_error("stack overflow detected; terminated");
4912 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
4918 _rtld_error("buffer overflow detected; terminated");
4923 rtld_strerror(int errnum)
4926 if (errnum < 0 || errnum >= sys_nerr)
4927 return ("Unknown error");
4928 return (sys_errlist[errnum]);