2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 * Dynamic linker for ELF.
33 * John Polstra <jdp@polstra.com>.
37 #error "GCC is needed to compile this file"
40 #include <sys/param.h>
41 #include <sys/mount.h>
44 #include <sys/sysctl.h>
46 #include <sys/utsname.h>
47 #include <sys/ktrace.h>
48 #include <sys/resident.h>
51 #include <machine/tls.h>
66 #include "rtld_printf.h"
68 #define PATH_RTLD "/usr/libexec/ld-elf.so.2"
69 #define LD_ARY_CACHE 16
72 typedef void (*func_ptr_type)();
73 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
76 * Function declarations.
78 static const char *_getenv_ld(const char *id);
79 static void die(void) __dead2;
80 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
82 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *);
83 static void digest_dynamic(Obj_Entry *, int);
84 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
85 static Obj_Entry *dlcheck(void *);
86 static Obj_Entry *dlopen_object(const char *name, Obj_Entry *refobj,
87 int lo_flags, int mode);
88 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
89 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
90 static bool donelist_check(DoneList *, const Obj_Entry *);
91 static void errmsg_restore(char *);
92 static char *errmsg_save(void);
93 static void *fill_search_info(const char *, size_t, void *);
94 static char *find_library(const char *, const Obj_Entry *);
95 static const char *gethints(void);
96 static void init_dag(Obj_Entry *);
97 static void init_dag1(Obj_Entry *, Obj_Entry *, DoneList *);
98 static void init_rtld(caddr_t, Elf_Auxinfo **);
99 static void initlist_add_neededs(Needed_Entry *, Objlist *);
100 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
101 static bool is_exported(const Elf_Sym *);
102 static void linkmap_add(Obj_Entry *);
103 static void linkmap_delete(Obj_Entry *);
104 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
105 static void unload_filtees(Obj_Entry *);
106 static int load_needed_objects(Obj_Entry *, int);
107 static int load_preload_objects(void);
108 static Obj_Entry *load_object(const char *, const Obj_Entry *, int);
109 static void map_stacks_exec(RtldLockState *);
110 static Obj_Entry *obj_from_addr(const void *);
111 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
112 static void objlist_call_init(Objlist *, RtldLockState *);
113 static void objlist_clear(Objlist *);
114 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
115 static void objlist_init(Objlist *);
116 static void objlist_push_head(Objlist *, Obj_Entry *);
117 static void objlist_push_tail(Objlist *, Obj_Entry *);
118 static void objlist_remove(Objlist *, Obj_Entry *);
119 static void *path_enumerate(const char *, path_enum_proc, void *);
120 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, RtldLockState *);
121 static int rtld_dirname(const char *, char *);
122 static int rtld_dirname_abs(const char *, char *);
123 static void rtld_exit(void);
124 static char *search_library_path(const char *, const char *);
125 static const void **get_program_var_addr(const char *);
126 static void set_program_var(const char *, const void *);
127 static int symlook_default(SymLook *, const Obj_Entry *refobj);
128 static void symlook_init_from_req(SymLook *, const SymLook *);
129 static int symlook_list(SymLook *, const Objlist *, DoneList *);
130 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
131 static int symlook_obj1(SymLook *, const Obj_Entry *);
132 static void trace_loaded_objects(Obj_Entry *);
133 static void unlink_object(Obj_Entry *);
134 static void unload_object(Obj_Entry *);
135 static void unref_dag(Obj_Entry *);
136 static void ref_dag(Obj_Entry *);
137 static int origin_subst_one(char **, const char *, const char *,
138 const char *, char *);
139 static char *origin_subst(const char *, const char *);
140 static int rtld_verify_versions(const Objlist *);
141 static int rtld_verify_object_versions(Obj_Entry *);
142 static void object_add_name(Obj_Entry *, const char *);
143 static int object_match_name(const Obj_Entry *, const char *);
144 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
145 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
146 struct dl_phdr_info *phdr_info);
148 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
153 static char *error_message; /* Message for dlerror(), or NULL */
154 struct r_debug r_debug; /* for GDB; */
155 static bool libmap_disable; /* Disable libmap */
156 static bool ld_loadfltr; /* Immediate filters processing */
157 static char *libmap_override; /* Maps to use in addition to libmap.conf */
158 static bool trust; /* False for setuid and setgid programs */
159 static bool dangerous_ld_env; /* True if environment variables have been
160 used to affect the libraries loaded */
161 static const char *ld_bind_now; /* Environment variable for immediate binding */
162 static const char *ld_debug; /* Environment variable for debugging */
163 static const char *ld_library_path; /* Environment variable for search path */
164 static char *ld_preload; /* Environment variable for libraries to
166 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
167 static const char *ld_tracing; /* Called from ldd to print libs */
168 static const char *ld_utrace; /* Use utrace() to log events. */
169 static int (*rtld_functrace)( /* Optional function call tracing hook */
170 const char *caller_obj,
171 const char *callee_obj,
172 const char *callee_func,
174 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */
175 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
176 static Obj_Entry **obj_tail; /* Link field of last object in list */
177 static Obj_Entry **preload_tail;
178 static Obj_Entry *obj_main; /* The main program shared object */
179 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
180 static unsigned int obj_count; /* Number of objects in obj_list */
181 static unsigned int obj_loads; /* Number of objects in obj_list */
183 static int ld_resident; /* Non-zero if resident */
184 static const char *ld_ary[LD_ARY_CACHE];
186 static Objlist initlist;
188 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
189 STAILQ_HEAD_INITIALIZER(list_global);
190 static Objlist list_main = /* Objects loaded at program startup */
191 STAILQ_HEAD_INITIALIZER(list_main);
192 static Objlist list_fini = /* Objects needing fini() calls */
193 STAILQ_HEAD_INITIALIZER(list_fini);
195 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
197 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
199 extern Elf_Dyn _DYNAMIC;
200 #pragma weak _DYNAMIC
201 #ifndef RTLD_IS_DYNAMIC
202 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
205 #ifdef ENABLE_OSRELDATE
209 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
210 static int max_stack_flags;
213 * These are the functions the dynamic linker exports to application
214 * programs. They are the only symbols the dynamic linker is willing
215 * to export from itself.
217 static func_ptr_type exports[] = {
218 (func_ptr_type) &_rtld_error,
219 (func_ptr_type) &dlclose,
220 (func_ptr_type) &dlerror,
221 (func_ptr_type) &dlopen,
222 (func_ptr_type) &dlfunc,
223 (func_ptr_type) &dlsym,
224 (func_ptr_type) &dlvsym,
225 (func_ptr_type) &dladdr,
226 (func_ptr_type) &dlinfo,
227 (func_ptr_type) &dl_iterate_phdr,
229 (func_ptr_type) &___tls_get_addr,
231 (func_ptr_type) &__tls_get_addr,
232 (func_ptr_type) &__tls_get_addr_tcb,
233 (func_ptr_type) &_rtld_allocate_tls,
234 (func_ptr_type) &_rtld_free_tls,
235 (func_ptr_type) &_rtld_call_init,
236 (func_ptr_type) &_rtld_thread_init,
237 (func_ptr_type) &_rtld_addr_phdr,
238 (func_ptr_type) &_rtld_get_stack_prot,
243 * Global declarations normally provided by crt1. The dynamic linker is
244 * not built with crt1, so we have to provide them ourselves.
250 * Globals to control TLS allocation.
252 size_t tls_last_offset; /* Static TLS offset of last module */
253 size_t tls_last_size; /* Static TLS size of last module */
254 size_t tls_static_space; /* Static TLS space allocated */
255 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
256 int tls_max_index = 1; /* Largest module index allocated */
259 * Fill in a DoneList with an allocation large enough to hold all of
260 * the currently-loaded objects. Keep this as a macro since it calls
261 * alloca and we want that to occur within the scope of the caller.
263 #define donelist_init(dlp) \
264 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
265 assert((dlp)->objs != NULL), \
266 (dlp)->num_alloc = obj_count, \
269 #define UTRACE_DLOPEN_START 1
270 #define UTRACE_DLOPEN_STOP 2
271 #define UTRACE_DLCLOSE_START 3
272 #define UTRACE_DLCLOSE_STOP 4
273 #define UTRACE_LOAD_OBJECT 5
274 #define UTRACE_UNLOAD_OBJECT 6
275 #define UTRACE_ADD_RUNDEP 7
276 #define UTRACE_PRELOAD_FINISHED 8
277 #define UTRACE_INIT_CALL 9
278 #define UTRACE_FINI_CALL 10
281 char sig[4]; /* 'RTLD' */
284 void *mapbase; /* Used for 'parent' and 'init/fini' */
286 int refcnt; /* Used for 'mode' */
287 char name[MAXPATHLEN];
290 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
291 if (ld_utrace != NULL) \
292 ld_utrace_log(e, h, mb, ms, r, n); \
296 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
297 int refcnt, const char *name)
299 struct utrace_rtld ut;
307 ut.mapbase = mapbase;
308 ut.mapsize = mapsize;
310 bzero(ut.name, sizeof(ut.name));
312 strlcpy(ut.name, name, sizeof(ut.name));
313 utrace(&ut, sizeof(ut));
317 * Main entry point for dynamic linking. The first argument is the
318 * stack pointer. The stack is expected to be laid out as described
319 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
320 * Specifically, the stack pointer points to a word containing
321 * ARGC. Following that in the stack is a null-terminated sequence
322 * of pointers to argument strings. Then comes a null-terminated
323 * sequence of pointers to environment strings. Finally, there is a
324 * sequence of "auxiliary vector" entries.
326 * The second argument points to a place to store the dynamic linker's
327 * exit procedure pointer and the third to a place to store the main
330 * The return value is the main program's entry point.
333 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
335 Elf_Auxinfo *aux_info[AT_COUNT];
343 Objlist_Entry *entry;
346 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld
347 Obj_Entry **preload_tail;
349 from global to here. It will break the DWARF2 unwind scheme.
350 The system compilers were unaffected, but not gcc 4.6
354 * On entry, the dynamic linker itself has not been relocated yet.
355 * Be very careful not to reference any global data until after
356 * init_rtld has returned. It is OK to reference file-scope statics
357 * and string constants, and to call static and global functions.
360 /* Find the auxiliary vector on the stack. */
363 sp += argc + 1; /* Skip over arguments and NULL terminator */
367 * If we aren't already resident we have to dig out some more info.
368 * Note that auxinfo does not exist when we are resident.
370 * I'm not sure about the ld_resident check. It seems to read zero
371 * prior to relocation, which is what we want. When running from a
372 * resident copy everything will be relocated so we are definitely
375 if (ld_resident == 0) {
376 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
378 aux = (Elf_Auxinfo *) sp;
380 /* Digest the auxiliary vector. */
381 for (i = 0; i < AT_COUNT; i++)
383 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
384 if (auxp->a_type < AT_COUNT)
385 aux_info[auxp->a_type] = auxp;
388 /* Initialize and relocate ourselves. */
389 assert(aux_info[AT_BASE] != NULL);
390 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
393 ld_index = 0; /* don't use old env cache in case we are resident */
394 __progname = obj_rtld.path;
395 argv0 = argv[0] != NULL ? argv[0] : "(null)";
398 trust = !issetugid();
400 ld_bind_now = _getenv_ld("LD_BIND_NOW");
402 * If the process is tainted, then we un-set the dangerous environment
403 * variables. The process will be marked as tainted until setuid(2)
404 * is called. If any child process calls setuid(2) we do not want any
405 * future processes to honor the potentially un-safe variables.
408 if ( unsetenv("LD_DEBUG")
409 || unsetenv("LD_PRELOAD")
410 || unsetenv("LD_LIBRARY_PATH")
411 || unsetenv("LD_ELF_HINTS_PATH")
412 || unsetenv("LD_LIBMAP")
413 || unsetenv("LD_LIBMAP_DISABLE")
414 || unsetenv("LD_LOADFLTR")
416 _rtld_error("environment corrupt; aborting");
420 ld_debug = _getenv_ld("LD_DEBUG");
421 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL;
422 libmap_override = (char *)_getenv_ld("LD_LIBMAP");
423 ld_library_path = _getenv_ld("LD_LIBRARY_PATH");
424 ld_preload = (char *)_getenv_ld("LD_PRELOAD");
425 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH");
426 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL;
427 dangerous_ld_env = (ld_library_path != NULL)
428 || (ld_preload != NULL)
429 || (ld_elf_hints_path != NULL)
431 || (libmap_override != NULL)
434 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS");
435 ld_utrace = _getenv_ld("LD_UTRACE");
437 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
438 ld_elf_hints_path = _PATH_ELF_HINTS;
440 if (ld_debug != NULL && *ld_debug != '\0')
442 dbg("%s is initialized, base address = %p", __progname,
443 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
444 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
445 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
447 dbg("initializing thread locks");
451 * If we are resident we can skip work that we have already done.
452 * Note that the stack is reset and there is no Elf_Auxinfo
453 * when running from a resident image, and the static globals setup
454 * between here and resident_skip will have already been setup.
460 * Load the main program, or process its program header if it is
463 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
464 int fd = aux_info[AT_EXECFD]->a_un.a_val;
465 dbg("loading main program");
466 obj_main = map_object(fd, argv0, NULL);
468 if (obj_main == NULL)
470 max_stack_flags = obj->stack_flags;
471 } else { /* Main program already loaded. */
472 const Elf_Phdr *phdr;
476 dbg("processing main program's program header");
477 assert(aux_info[AT_PHDR] != NULL);
478 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
479 assert(aux_info[AT_PHNUM] != NULL);
480 phnum = aux_info[AT_PHNUM]->a_un.a_val;
481 assert(aux_info[AT_PHENT] != NULL);
482 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
483 assert(aux_info[AT_ENTRY] != NULL);
484 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
485 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
489 char buf[MAXPATHLEN];
490 if (aux_info[AT_EXECPATH] != 0) {
493 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
494 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
495 if (kexecpath[0] == '/')
496 obj_main->path = kexecpath;
497 else if (getcwd(buf, sizeof(buf)) == NULL ||
498 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
499 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
500 obj_main->path = xstrdup(argv0);
502 obj_main->path = xstrdup(buf);
504 char resolved[MAXPATHLEN];
505 dbg("No AT_EXECPATH");
506 if (argv0[0] == '/') {
507 if (realpath(argv0, resolved) != NULL)
508 obj_main->path = xstrdup(resolved);
510 obj_main->path = xstrdup(argv0);
512 if (getcwd(buf, sizeof(buf)) != NULL
513 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf)
514 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf)
515 && access(buf, R_OK) == 0
516 && realpath(buf, resolved) != NULL)
517 obj_main->path = xstrdup(resolved);
519 obj_main->path = xstrdup(argv0);
522 dbg("obj_main path %s", obj_main->path);
523 obj_main->mainprog = true;
525 if (aux_info[AT_STACKPROT] != NULL &&
526 aux_info[AT_STACKPROT]->a_un.a_val != 0)
527 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
530 * Get the actual dynamic linker pathname from the executable if
531 * possible. (It should always be possible.) That ensures that
532 * gdb will find the right dynamic linker even if a non-standard
535 if (obj_main->interp != NULL &&
536 strcmp(obj_main->interp, obj_rtld.path) != 0) {
538 obj_rtld.path = xstrdup(obj_main->interp);
539 __progname = obj_rtld.path;
542 digest_dynamic(obj_main, 0);
544 linkmap_add(obj_main);
545 linkmap_add(&obj_rtld);
547 /* Link the main program into the list of objects. */
548 *obj_tail = obj_main;
549 obj_tail = &obj_main->next;
552 /* Make sure we don't call the main program's init and fini functions. */
553 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
555 /* Initialize a fake symbol for resolving undefined weak references. */
556 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
557 sym_zero.st_shndx = SHN_UNDEF;
558 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
561 libmap_disable = (bool)lm_init(libmap_override);
563 dbg("loading LD_PRELOAD libraries");
564 if (load_preload_objects() == -1)
566 preload_tail = obj_tail;
568 dbg("loading needed objects");
569 if (load_needed_objects(obj_main, 0) == -1)
572 /* Make a list of all objects loaded at startup. */
573 for (obj = obj_list; obj != NULL; obj = obj->next) {
574 objlist_push_tail(&list_main, obj);
578 dbg("checking for required versions");
579 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
584 if (ld_tracing) { /* We're done */
585 trace_loaded_objects(obj_main);
589 if (ld_resident) /* XXX clean this up! */
592 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) {
593 dump_relocations(obj_main);
597 /* setup TLS for main thread */
598 dbg("initializing initial thread local storage");
599 STAILQ_FOREACH(entry, &list_main, link) {
601 * Allocate all the initial objects out of the static TLS
602 * block even if they didn't ask for it.
604 allocate_tls_offset(entry->obj);
607 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
610 * Do not try to allocate the TLS here, let libc do it itself.
611 * (crt1 for the program will call _init_tls())
614 if (relocate_objects(obj_main,
615 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, NULL) == -1)
618 dbg("doing copy relocations");
619 if (do_copy_relocations(obj_main) == -1)
624 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) {
625 if (exec_sys_unregister(-1) < 0) {
626 dbg("exec_sys_unregister failed %d\n", errno);
629 dbg("exec_sys_unregister success\n");
633 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) {
634 dump_relocations(obj_main);
638 dbg("initializing key program variables");
639 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
640 set_program_var("environ", env);
641 set_program_var("__elf_aux_vector", aux);
643 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) {
644 extern void resident_start(void);
646 if (exec_sys_register(resident_start) < 0) {
647 dbg("exec_sys_register failed %d\n", errno);
650 dbg("exec_sys_register success\n");
654 /* Make a list of init functions to call. */
655 objlist_init(&initlist);
656 initlist_add_objects(obj_list, preload_tail, &initlist);
658 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
660 map_stacks_exec(NULL);
663 * Do NOT call the initlist here, give libc a chance to set up
664 * the initial TLS segment. crt1 will then call _rtld_call_init().
667 dbg("transferring control to program entry point = %p", obj_main->entry);
669 /* Return the exit procedure and the program entry point. */
670 *exit_proc = rtld_exit;
672 return (func_ptr_type) obj_main->entry;
676 * Call the initialization list for dynamically loaded libraries.
677 * (called from crt1.c).
680 _rtld_call_init(void)
682 RtldLockState lockstate;
685 wlock_acquire(rtld_bind_lock, &lockstate);
686 objlist_call_init(&initlist, &lockstate);
687 objlist_clear(&initlist);
688 dbg("loading filtees");
689 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
690 if (ld_loadfltr || obj->z_loadfltr)
691 load_filtees(obj, 0, &lockstate);
693 lock_release(rtld_bind_lock, &lockstate);
697 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack)
701 const Obj_Entry *defobj;
704 RtldLockState lockstate;
706 rlock_acquire(rtld_bind_lock, &lockstate);
707 if (sigsetjmp(lockstate.env, 0) != 0)
708 lock_upgrade(rtld_bind_lock, &lockstate);
710 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
712 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
714 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
715 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
720 target = (Elf_Addr)(defobj->relocbase + def->st_value);
722 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
723 defobj->strtab + def->st_name, basename(obj->path),
724 (void *)target, basename(defobj->path));
727 * If we have a function call tracing hook, and the
728 * hook would like to keep tracing this one function,
729 * prevent the relocation so we will wind up here
730 * the next time again.
732 * We don't want to functrace calls from the functracer
733 * to avoid recursive loops.
735 if (rtld_functrace != NULL && obj != rtld_functrace_obj) {
736 if (rtld_functrace(obj->path,
738 defobj->strtab + def->st_name,
740 lock_release(rtld_bind_lock, &lockstate);
745 * Write the new contents for the jmpslot. Note that depending on
746 * architecture, the value which we need to return back to the
747 * lazy binding trampoline may or may not be the target
748 * address. The value returned from reloc_jmpslot() is the value
749 * that the trampoline needs.
751 target = reloc_jmpslot(where, target, defobj, obj, rel);
752 lock_release(rtld_bind_lock, &lockstate);
757 * Error reporting function. Use it like printf. If formats the message
758 * into a buffer, and sets things up so that the next call to dlerror()
759 * will return the message.
762 _rtld_error(const char *fmt, ...)
764 static char buf[512];
768 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
774 * Return a dynamically-allocated copy of the current error message, if any.
779 return error_message == NULL ? NULL : xstrdup(error_message);
783 * Restore the current error message from a copy which was previously saved
784 * by errmsg_save(). The copy is freed.
787 errmsg_restore(char *saved_msg)
789 if (saved_msg == NULL)
790 error_message = NULL;
792 _rtld_error("%s", saved_msg);
798 basename(const char *name)
800 const char *p = strrchr(name, '/');
801 return p != NULL ? p + 1 : name;
804 static struct utsname uts;
807 origin_subst_one(char **res, const char *real, const char *kw, const char *subst,
817 subst_len = kw_len = 0;
821 if (subst_len == 0) {
822 subst_len = strlen(subst);
826 *res = xmalloc(PATH_MAX);
829 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) {
830 _rtld_error("Substitution of %s in %s cannot be performed",
832 if (may_free != NULL)
837 memcpy(res1, p, p1 - p);
839 memcpy(res1, subst, subst_len);
844 if (may_free != NULL)
847 *res = xstrdup(real);
851 if (may_free != NULL)
853 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) {
863 origin_subst(const char *real, const char *origin_path)
865 char *res1, *res2, *res3, *res4;
867 if (uts.sysname[0] == '\0') {
868 if (uname(&uts) != 0) {
869 _rtld_error("utsname failed: %d", errno);
873 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) ||
874 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) ||
875 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) ||
876 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3))
884 const char *msg = dlerror();
888 rtld_fdputstr(STDERR_FILENO, msg);
893 * Process a shared object's DYNAMIC section, and save the important
894 * information in its Obj_Entry structure.
897 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
898 const Elf_Dyn **dyn_soname)
901 Needed_Entry **needed_tail = &obj->needed;
902 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
903 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
904 int plttype = DT_REL;
909 obj->bind_now = false;
910 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
911 switch (dynp->d_tag) {
914 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
918 obj->relsize = dynp->d_un.d_val;
922 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
926 obj->pltrel = (const Elf_Rel *)
927 (obj->relocbase + dynp->d_un.d_ptr);
931 obj->pltrelsize = dynp->d_un.d_val;
935 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
939 obj->relasize = dynp->d_un.d_val;
943 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
947 plttype = dynp->d_un.d_val;
948 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
952 obj->symtab = (const Elf_Sym *)
953 (obj->relocbase + dynp->d_un.d_ptr);
957 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
961 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
965 obj->strsize = dynp->d_un.d_val;
969 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
974 obj->verneednum = dynp->d_un.d_val;
978 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
983 obj->verdefnum = dynp->d_un.d_val;
987 obj->versyms = (const Elf_Versym *)(obj->relocbase +
993 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
994 (obj->relocbase + dynp->d_un.d_ptr);
995 obj->nbuckets = hashtab[0];
996 obj->nchains = hashtab[1];
997 obj->buckets = hashtab + 2;
998 obj->chains = obj->buckets + obj->nbuckets;
1004 Needed_Entry *nep = NEW(Needed_Entry);
1005 nep->name = dynp->d_un.d_val;
1010 needed_tail = &nep->next;
1016 Needed_Entry *nep = NEW(Needed_Entry);
1017 nep->name = dynp->d_un.d_val;
1021 *needed_filtees_tail = nep;
1022 needed_filtees_tail = &nep->next;
1028 Needed_Entry *nep = NEW(Needed_Entry);
1029 nep->name = dynp->d_un.d_val;
1033 *needed_aux_filtees_tail = nep;
1034 needed_aux_filtees_tail = &nep->next;
1039 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1043 obj->textrel = true;
1047 obj->symbolic = true;
1051 case DT_RUNPATH: /* XXX: process separately */
1053 * We have to wait until later to process this, because we
1054 * might not have gotten the address of the string table yet.
1064 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1068 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1072 /* XXX - not implemented yet */
1074 dbg("Filling in DT_DEBUG entry");
1075 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1079 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1080 obj->z_origin = true;
1081 if (dynp->d_un.d_val & DF_SYMBOLIC)
1082 obj->symbolic = true;
1083 if (dynp->d_un.d_val & DF_TEXTREL)
1084 obj->textrel = true;
1085 if (dynp->d_un.d_val & DF_BIND_NOW)
1086 obj->bind_now = true;
1087 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1092 if (dynp->d_un.d_val & DF_1_NOOPEN)
1093 obj->z_noopen = true;
1094 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1095 obj->z_origin = true;
1096 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1098 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1099 obj->bind_now = true;
1100 if (dynp->d_un.d_val & DF_1_NODELETE)
1101 obj->z_nodelete = true;
1102 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1103 obj->z_loadfltr = true;
1108 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1115 obj->traced = false;
1117 if (plttype == DT_RELA) {
1118 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1120 obj->pltrelasize = obj->pltrelsize;
1121 obj->pltrelsize = 0;
1126 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1127 const Elf_Dyn *dyn_soname)
1130 if (obj->z_origin && obj->origin_path == NULL) {
1131 obj->origin_path = xmalloc(PATH_MAX);
1132 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1136 if (dyn_rpath != NULL) {
1137 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1139 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1142 if (dyn_soname != NULL)
1143 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1147 digest_dynamic(Obj_Entry *obj, int early)
1149 const Elf_Dyn *dyn_rpath;
1150 const Elf_Dyn *dyn_soname;
1152 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname);
1153 digest_dynamic2(obj, dyn_rpath, dyn_soname);
1157 * Process a shared object's program header. This is used only for the
1158 * main program, when the kernel has already loaded the main program
1159 * into memory before calling the dynamic linker. It creates and
1160 * returns an Obj_Entry structure.
1163 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1166 const Elf_Phdr *phlimit = phdr + phnum;
1171 for (ph = phdr; ph < phlimit; ph++) {
1172 if (ph->p_type != PT_PHDR)
1176 obj->phsize = ph->p_memsz;
1177 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1181 obj->stack_flags = PF_X | PF_R | PF_W;
1183 for (ph = phdr; ph < phlimit; ph++) {
1184 switch (ph->p_type) {
1187 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1191 if (nsegs == 0) { /* First load segment */
1192 obj->vaddrbase = trunc_page(ph->p_vaddr);
1193 obj->mapbase = obj->vaddrbase + obj->relocbase;
1194 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1196 } else { /* Last load segment */
1197 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1204 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1209 obj->tlssize = ph->p_memsz;
1210 obj->tlsalign = ph->p_align;
1211 obj->tlsinitsize = ph->p_filesz;
1212 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1216 obj->stack_flags = ph->p_flags;
1220 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1221 obj->relro_size = round_page(ph->p_memsz);
1226 _rtld_error("%s: too few PT_LOAD segments", path);
1235 dlcheck(void *handle)
1239 for (obj = obj_list; obj != NULL; obj = obj->next)
1240 if (obj == (Obj_Entry *) handle)
1243 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1244 _rtld_error("Invalid shared object handle %p", handle);
1251 * If the given object is already in the donelist, return true. Otherwise
1252 * add the object to the list and return false.
1255 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1259 for (i = 0; i < dlp->num_used; i++)
1260 if (dlp->objs[i] == obj)
1263 * Our donelist allocation should always be sufficient. But if
1264 * our threads locking isn't working properly, more shared objects
1265 * could have been loaded since we allocated the list. That should
1266 * never happen, but we'll handle it properly just in case it does.
1268 if (dlp->num_used < dlp->num_alloc)
1269 dlp->objs[dlp->num_used++] = obj;
1274 * Hash function for symbol table lookup. Don't even think about changing
1275 * this. It is specified by the System V ABI.
1278 elf_hash(const char *name)
1280 const unsigned char *p = (const unsigned char *) name;
1281 unsigned long h = 0;
1284 while (*p != '\0') {
1285 h = (h << 4) + *p++;
1286 if ((g = h & 0xf0000000) != 0)
1294 * Find the library with the given name, and return its full pathname.
1295 * The returned string is dynamically allocated. Generates an error
1296 * message and returns NULL if the library cannot be found.
1298 * If the second argument is non-NULL, then it refers to an already-
1299 * loaded shared object, whose library search path will be searched.
1301 * The search order is:
1303 * rpath in the referencing file
1308 find_library(const char *xname, const Obj_Entry *refobj)
1313 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1314 if (xname[0] != '/' && !trust) {
1315 _rtld_error("Absolute pathname required for shared object \"%s\"",
1319 if (refobj != NULL && refobj->z_origin)
1320 return origin_subst(xname, refobj->origin_path);
1322 return xstrdup(xname);
1325 if (libmap_disable || (refobj == NULL) ||
1326 (name = lm_find(refobj->path, xname)) == NULL)
1327 name = (char *)xname;
1329 dbg(" Searching for \"%s\"", name);
1331 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1333 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1334 (pathname = search_library_path(name, gethints())) != NULL ||
1335 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1338 if(refobj != NULL && refobj->path != NULL) {
1339 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1340 name, basename(refobj->path));
1342 _rtld_error("Shared object \"%s\" not found", name);
1348 * Given a symbol number in a referencing object, find the corresponding
1349 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1350 * no definition was found. Returns a pointer to the Obj_Entry of the
1351 * defining object via the reference parameter DEFOBJ_OUT.
1354 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1355 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1356 RtldLockState *lockstate)
1360 const Obj_Entry *defobj;
1366 * If we have already found this symbol, get the information from
1369 if (symnum >= refobj->nchains)
1370 return NULL; /* Bad object */
1371 if (cache != NULL && cache[symnum].sym != NULL) {
1372 *defobj_out = cache[symnum].obj;
1373 return cache[symnum].sym;
1376 ref = refobj->symtab + symnum;
1377 name = refobj->strtab + ref->st_name;
1382 * We don't have to do a full scale lookup if the symbol is local.
1383 * We know it will bind to the instance in this load module; to
1384 * which we already have a pointer (ie ref). By not doing a lookup,
1385 * we not only improve performance, but it also avoids unresolvable
1386 * symbols when local symbols are not in the hash table.
1388 * This might occur for TLS module relocations, which simply use
1391 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1392 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1393 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1396 symlook_init(&req, name);
1398 req.ventry = fetch_ventry(refobj, symnum);
1399 req.lockstate = lockstate;
1400 res = symlook_default(&req, refobj);
1403 defobj = req.defobj_out;
1411 * If we found no definition and the reference is weak, treat the
1412 * symbol as having the value zero.
1414 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1420 *defobj_out = defobj;
1421 /* Record the information in the cache to avoid subsequent lookups. */
1422 if (cache != NULL) {
1423 cache[symnum].sym = def;
1424 cache[symnum].obj = defobj;
1427 if (refobj != &obj_rtld)
1428 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1434 * Return the search path from the ldconfig hints file, reading it if
1435 * necessary. Returns NULL if there are problems with the hints file,
1436 * or if the search path there is empty.
1443 if (hints == NULL) {
1445 struct elfhints_hdr hdr;
1448 /* Keep from trying again in case the hints file is bad. */
1451 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1453 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1454 hdr.magic != ELFHINTS_MAGIC ||
1459 p = xmalloc(hdr.dirlistlen + 1);
1460 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1461 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1469 return hints[0] != '\0' ? hints : NULL;
1473 init_dag(Obj_Entry *root)
1477 if (root->dag_inited)
1479 donelist_init(&donelist);
1480 init_dag1(root, root, &donelist);
1481 root->dag_inited = true;
1485 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp)
1487 const Needed_Entry *needed;
1489 if (donelist_check(dlp, obj))
1492 objlist_push_tail(&obj->dldags, root);
1493 objlist_push_tail(&root->dagmembers, obj);
1494 for (needed = obj->needed; needed != NULL; needed = needed->next)
1495 if (needed->obj != NULL)
1496 init_dag1(root, needed->obj, dlp);
1500 * Initialize the dynamic linker. The argument is the address at which
1501 * the dynamic linker has been mapped into memory. The primary task of
1502 * this function is to relocate the dynamic linker.
1505 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1507 Obj_Entry objtmp; /* Temporary rtld object */
1508 const Elf_Dyn *dyn_rpath;
1509 const Elf_Dyn *dyn_soname;
1512 * Conjure up an Obj_Entry structure for the dynamic linker.
1514 * The "path" member can't be initialized yet because string constants
1515 * cannot yet be accessed. Below we will set it correctly.
1517 memset(&objtmp, 0, sizeof(objtmp));
1520 objtmp.mapbase = mapbase;
1522 objtmp.relocbase = mapbase;
1524 if (RTLD_IS_DYNAMIC()) {
1525 objtmp.dynamic = rtld_dynamic(&objtmp);
1526 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname);
1527 assert(objtmp.needed == NULL);
1528 assert(!objtmp.textrel);
1531 * Temporarily put the dynamic linker entry into the object list, so
1532 * that symbols can be found.
1535 relocate_objects(&objtmp, true, &objtmp, NULL);
1538 /* Initialize the object list. */
1539 obj_tail = &obj_list;
1541 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1542 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1544 #ifdef ENABLE_OSRELDATE
1545 if (aux_info[AT_OSRELDATE] != NULL)
1546 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1549 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname);
1551 /* Replace the path with a dynamically allocated copy. */
1552 obj_rtld.path = xstrdup(PATH_RTLD);
1554 r_debug.r_brk = r_debug_state;
1555 r_debug.r_state = RT_CONSISTENT;
1559 * Add the init functions from a needed object list (and its recursive
1560 * needed objects) to "list". This is not used directly; it is a helper
1561 * function for initlist_add_objects(). The write lock must be held
1562 * when this function is called.
1565 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1567 /* Recursively process the successor needed objects. */
1568 if (needed->next != NULL)
1569 initlist_add_neededs(needed->next, list);
1571 /* Process the current needed object. */
1572 if (needed->obj != NULL)
1573 initlist_add_objects(needed->obj, &needed->obj->next, list);
1577 * Scan all of the DAGs rooted in the range of objects from "obj" to
1578 * "tail" and add their init functions to "list". This recurses over
1579 * the DAGs and ensure the proper init ordering such that each object's
1580 * needed libraries are initialized before the object itself. At the
1581 * same time, this function adds the objects to the global finalization
1582 * list "list_fini" in the opposite order. The write lock must be
1583 * held when this function is called.
1586 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1588 if (obj->init_scanned || obj->init_done)
1590 obj->init_scanned = true;
1592 /* Recursively process the successor objects. */
1593 if (&obj->next != tail)
1594 initlist_add_objects(obj->next, tail, list);
1596 /* Recursively process the needed objects. */
1597 if (obj->needed != NULL)
1598 initlist_add_neededs(obj->needed, list);
1600 /* Add the object to the init list. */
1601 if (obj->init != (Elf_Addr)NULL)
1602 objlist_push_tail(list, obj);
1604 /* Add the object to the global fini list in the reverse order. */
1605 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) {
1606 objlist_push_head(&list_fini, obj);
1607 obj->on_fini_list = true;
1612 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1616 is_exported(const Elf_Sym *def)
1619 const func_ptr_type *p;
1621 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value);
1622 for (p = exports; *p != NULL; p++)
1623 if (FPTR_TARGET(*p) == value)
1629 free_needed_filtees(Needed_Entry *n)
1631 Needed_Entry *needed, *needed1;
1633 for (needed = n; needed != NULL; needed = needed->next) {
1634 if (needed->obj != NULL) {
1635 dlclose(needed->obj);
1639 for (needed = n; needed != NULL; needed = needed1) {
1640 needed1 = needed->next;
1646 unload_filtees(Obj_Entry *obj)
1649 free_needed_filtees(obj->needed_filtees);
1650 obj->needed_filtees = NULL;
1651 free_needed_filtees(obj->needed_aux_filtees);
1652 obj->needed_aux_filtees = NULL;
1653 obj->filtees_loaded = false;
1657 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags)
1660 for (; needed != NULL; needed = needed->next) {
1661 needed->obj = dlopen_object(obj->strtab + needed->name, obj,
1662 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1668 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1671 lock_restart_for_upgrade(lockstate);
1672 if (!obj->filtees_loaded) {
1673 load_filtee1(obj, obj->needed_filtees, flags);
1674 load_filtee1(obj, obj->needed_aux_filtees, flags);
1675 obj->filtees_loaded = true;
1680 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1684 for (; needed != NULL; needed = needed->next) {
1685 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj,
1686 flags & ~RTLD_LO_NOLOAD);
1687 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1689 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
1690 dbg("obj %s nodelete", obj1->path);
1693 obj1->ref_nodel = true;
1700 * Given a shared object, traverse its list of needed objects, and load
1701 * each of them. Returns 0 on success. Generates an error message and
1702 * returns -1 on failure.
1705 load_needed_objects(Obj_Entry *first, int flags)
1709 for (obj = first; obj != NULL; obj = obj->next) {
1710 if (process_needed(obj, obj->needed, flags) == -1)
1717 load_preload_objects(void)
1719 char *p = ld_preload;
1720 static const char delim[] = " \t:;";
1725 p += strspn(p, delim);
1726 while (*p != '\0') {
1727 size_t len = strcspn(p, delim);
1735 obj = load_object(p, NULL, 0);
1737 return -1; /* XXX - cleanup */
1740 p += strspn(p, delim);
1742 /* Check for the magic tracing function */
1743 symlook_init(&req, RTLD_FUNCTRACE);
1744 res = symlook_obj(&req, obj);
1746 rtld_functrace = (void *)(req.defobj_out->relocbase +
1747 req.sym_out->st_value);
1748 rtld_functrace_obj = req.defobj_out;
1751 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
1756 * Load a shared object into memory, if it is not already loaded.
1758 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1762 load_object(const char *name, const Obj_Entry *refobj, int flags)
1769 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1770 if (object_match_name(obj, name))
1773 path = find_library(name, refobj);
1778 * If we didn't find a match by pathname, open the file and check
1779 * again by device and inode. This avoids false mismatches caused
1780 * by multiple links or ".." in pathnames.
1782 * To avoid a race, we open the file and use fstat() rather than
1785 if ((fd = open(path, O_RDONLY)) == -1) {
1786 _rtld_error("Cannot open \"%s\"", path);
1790 if (fstat(fd, &sb) == -1) {
1791 _rtld_error("Cannot fstat \"%s\"", path);
1796 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1797 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
1800 object_add_name(obj, name);
1805 if (flags & RTLD_LO_NOLOAD) {
1811 /* First use of this object, so we must map it in */
1812 obj = do_load_object(fd, name, path, &sb, flags);
1821 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
1828 * but first, make sure that environment variables haven't been
1829 * used to circumvent the noexec flag on a filesystem.
1831 if (dangerous_ld_env) {
1832 if (fstatfs(fd, &fs) != 0) {
1833 _rtld_error("Cannot fstatfs \"%s\"", path);
1836 if (fs.f_flags & MNT_NOEXEC) {
1837 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
1841 dbg("loading \"%s\"", path);
1842 obj = map_object(fd, path, sbp);
1846 object_add_name(obj, name);
1848 digest_dynamic(obj, 0);
1849 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
1851 dbg("refusing to load non-loadable \"%s\"", obj->path);
1852 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
1853 munmap(obj->mapbase, obj->mapsize);
1859 obj_tail = &obj->next;
1862 linkmap_add(obj); /* for GDB & dlinfo() */
1863 max_stack_flags |= obj->stack_flags;
1865 dbg(" %p .. %p: %s", obj->mapbase,
1866 obj->mapbase + obj->mapsize - 1, obj->path);
1868 dbg(" WARNING: %s has impure text", obj->path);
1869 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
1876 obj_from_addr(const void *addr)
1880 for (obj = obj_list; obj != NULL; obj = obj->next) {
1881 if (addr < (void *) obj->mapbase)
1883 if (addr < (void *) (obj->mapbase + obj->mapsize))
1890 * Call the finalization functions for each of the objects in "list"
1891 * belonging to the DAG of "root" and referenced once. If NULL "root"
1892 * is specified, every finalization function will be called regardless
1893 * of the reference count and the list elements won't be freed. All of
1894 * the objects are expected to have non-NULL fini functions.
1897 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
1902 assert(root == NULL || root->refcount == 1);
1905 * Preserve the current error message since a fini function might
1906 * call into the dynamic linker and overwrite it.
1908 saved_msg = errmsg_save();
1910 STAILQ_FOREACH(elm, list, link) {
1911 if (root != NULL && (elm->obj->refcount != 1 ||
1912 objlist_find(&root->dagmembers, elm->obj) == NULL))
1914 dbg("calling fini function for %s at %p", elm->obj->path,
1915 (void *)elm->obj->fini);
1916 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0,
1918 /* Remove object from fini list to prevent recursive invocation. */
1919 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1921 * XXX: If a dlopen() call references an object while the
1922 * fini function is in progress, we might end up trying to
1923 * unload the referenced object in dlclose() or the object
1924 * won't be unloaded although its fini function has been
1927 lock_release(rtld_bind_lock, lockstate);
1928 call_initfini_pointer(elm->obj, elm->obj->fini);
1929 wlock_acquire(rtld_bind_lock, lockstate);
1930 /* No need to free anything if process is going down. */
1934 * We must restart the list traversal after every fini call
1935 * because a dlclose() call from the fini function or from
1936 * another thread might have modified the reference counts.
1940 } while (elm != NULL);
1941 errmsg_restore(saved_msg);
1945 * Call the initialization functions for each of the objects in
1946 * "list". All of the objects are expected to have non-NULL init
1950 objlist_call_init(Objlist *list, RtldLockState *lockstate)
1957 * Clean init_scanned flag so that objects can be rechecked and
1958 * possibly initialized earlier if any of vectors called below
1959 * cause the change by using dlopen.
1961 for (obj = obj_list; obj != NULL; obj = obj->next)
1962 obj->init_scanned = false;
1965 * Preserve the current error message since an init function might
1966 * call into the dynamic linker and overwrite it.
1968 saved_msg = errmsg_save();
1969 STAILQ_FOREACH(elm, list, link) {
1970 if (elm->obj->init_done) /* Initialized early. */
1972 dbg("calling init function for %s at %p", elm->obj->path,
1973 (void *)elm->obj->init);
1974 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0,
1977 * Race: other thread might try to use this object before current
1978 * one completes the initilization. Not much can be done here
1979 * without better locking.
1981 elm->obj->init_done = true;
1982 lock_release(rtld_bind_lock, lockstate);
1983 call_initfini_pointer(elm->obj, elm->obj->init);
1984 wlock_acquire(rtld_bind_lock, lockstate);
1986 errmsg_restore(saved_msg);
1990 objlist_clear(Objlist *list)
1994 while (!STAILQ_EMPTY(list)) {
1995 elm = STAILQ_FIRST(list);
1996 STAILQ_REMOVE_HEAD(list, link);
2001 static Objlist_Entry *
2002 objlist_find(Objlist *list, const Obj_Entry *obj)
2006 STAILQ_FOREACH(elm, list, link)
2007 if (elm->obj == obj)
2013 objlist_init(Objlist *list)
2019 objlist_push_head(Objlist *list, Obj_Entry *obj)
2023 elm = NEW(Objlist_Entry);
2025 STAILQ_INSERT_HEAD(list, elm, link);
2029 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2033 elm = NEW(Objlist_Entry);
2035 STAILQ_INSERT_TAIL(list, elm, link);
2039 objlist_remove(Objlist *list, Obj_Entry *obj)
2043 if ((elm = objlist_find(list, obj)) != NULL) {
2044 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2050 * Relocate newly-loaded shared objects. The argument is a pointer to
2051 * the Obj_Entry for the first such object. All objects from the first
2052 * to the end of the list of objects are relocated. Returns 0 on success,
2056 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2057 RtldLockState *lockstate)
2061 for (obj = first; obj != NULL; obj = obj->next) {
2063 dbg("relocating \"%s\"", obj->path);
2064 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
2065 obj->symtab == NULL || obj->strtab == NULL) {
2066 _rtld_error("%s: Shared object has no run-time symbol table",
2072 /* There are relocations to the write-protected text segment. */
2073 if (mprotect(obj->mapbase, obj->textsize,
2074 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2075 _rtld_error("%s: Cannot write-enable text segment: %s",
2076 obj->path, strerror(errno));
2081 /* Process the non-PLT relocations. */
2082 if (reloc_non_plt(obj, rtldobj, lockstate))
2086 * Reprotect the text segment. Make sure it is included in the
2087 * core dump since we modified it. This unfortunately causes the
2088 * entire text segment to core-out but we don't have much of a
2089 * choice. We could try to only reenable core dumps on pages
2090 * in which relocations occured but that is likely most of the text
2091 * pages anyway, and even that would not work because the rest of
2092 * the text pages would wind up as a read-only OBJT_DEFAULT object
2093 * (created due to our modifications) backed by the original OBJT_VNODE
2094 * object, and the ELF coredump code is currently only able to dump
2095 * vnode records for pure vnode-backed mappings, not vnode backings
2096 * to memory objects.
2099 madvise(obj->mapbase, obj->textsize, MADV_CORE);
2100 if (mprotect(obj->mapbase, obj->textsize,
2101 PROT_READ|PROT_EXEC) == -1) {
2102 _rtld_error("%s: Cannot write-protect text segment: %s",
2103 obj->path, strerror(errno));
2108 /* Process the PLT relocations. */
2109 if (reloc_plt(obj) == -1)
2111 /* Relocate the jump slots if we are doing immediate binding. */
2112 if (obj->bind_now || bind_now)
2113 if (reloc_jmpslots(obj, lockstate) == -1)
2116 /* Set the special PLT or GOT entries. */
2120 * Set up the magic number and version in the Obj_Entry. These
2121 * were checked in the crt1.o from the original ElfKit, so we
2122 * set them for backward compatibility.
2124 obj->magic = RTLD_MAGIC;
2125 obj->version = RTLD_VERSION;
2128 * Set relocated data to read-only status if protection specified
2131 if (obj->relro_size) {
2132 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
2133 _rtld_error("%s: Cannot enforce relro relocation: %s",
2134 obj->path, strerror(errno));
2144 * Cleanup procedure. It will be called (by the atexit mechanism) just
2145 * before the process exits.
2150 RtldLockState lockstate;
2152 wlock_acquire(rtld_bind_lock, &lockstate);
2154 objlist_call_fini(&list_fini, NULL, &lockstate);
2155 /* No need to remove the items from the list, since we are exiting. */
2156 if (!libmap_disable)
2158 lock_release(rtld_bind_lock, &lockstate);
2162 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2167 path += strspn(path, ":;");
2168 while (*path != '\0') {
2172 len = strcspn(path, ":;");
2173 res = callback(path, len, arg);
2179 path += strspn(path, ":;");
2185 struct try_library_args {
2193 try_library_path(const char *dir, size_t dirlen, void *param)
2195 struct try_library_args *arg;
2198 if (*dir == '/' || trust) {
2201 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2204 pathname = arg->buffer;
2205 strncpy(pathname, dir, dirlen);
2206 pathname[dirlen] = '/';
2207 strcpy(pathname + dirlen + 1, arg->name);
2209 dbg(" Trying \"%s\"", pathname);
2210 if (access(pathname, F_OK) == 0) { /* We found it */
2211 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2212 strcpy(pathname, arg->buffer);
2220 search_library_path(const char *name, const char *path)
2223 struct try_library_args arg;
2229 arg.namelen = strlen(name);
2230 arg.buffer = xmalloc(PATH_MAX);
2231 arg.buflen = PATH_MAX;
2233 p = path_enumerate(path, try_library_path, &arg);
2241 dlclose(void *handle)
2244 RtldLockState lockstate;
2246 wlock_acquire(rtld_bind_lock, &lockstate);
2247 root = dlcheck(handle);
2249 lock_release(rtld_bind_lock, &lockstate);
2252 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2255 /* Unreference the object and its dependencies. */
2256 root->dl_refcount--;
2258 if (root->refcount == 1) {
2260 * The object will be no longer referenced, so we must unload it.
2261 * First, call the fini functions.
2263 objlist_call_fini(&list_fini, root, &lockstate);
2267 /* Finish cleaning up the newly-unreferenced objects. */
2268 GDB_STATE(RT_DELETE,&root->linkmap);
2269 unload_object(root);
2270 GDB_STATE(RT_CONSISTENT,NULL);
2274 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2275 lock_release(rtld_bind_lock, &lockstate);
2282 char *msg = error_message;
2283 error_message = NULL;
2288 dlopen(const char *name, int mode)
2292 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2293 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2294 if (ld_tracing != NULL)
2295 environ = (char **)*get_program_var_addr("environ");
2296 lo_flags = RTLD_LO_DLOPEN;
2297 if (mode & RTLD_NODELETE)
2298 lo_flags |= RTLD_LO_NODELETE;
2299 if (mode & RTLD_NOLOAD)
2300 lo_flags |= RTLD_LO_NOLOAD;
2301 if (ld_tracing != NULL)
2302 lo_flags |= RTLD_LO_TRACE;
2304 return (dlopen_object(name, obj_main, lo_flags,
2305 mode & (RTLD_MODEMASK | RTLD_GLOBAL)));
2309 dlopen_object(const char *name, Obj_Entry *refobj, int lo_flags, int mode)
2311 Obj_Entry **old_obj_tail;
2314 RtldLockState lockstate;
2317 objlist_init(&initlist);
2319 wlock_acquire(rtld_bind_lock, &lockstate);
2320 GDB_STATE(RT_ADD,NULL);
2322 old_obj_tail = obj_tail;
2328 obj = load_object(name, refobj, lo_flags);
2333 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2334 objlist_push_tail(&list_global, obj);
2335 if (*old_obj_tail != NULL) { /* We loaded something new. */
2336 assert(*old_obj_tail == obj);
2337 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN);
2341 result = rtld_verify_versions(&obj->dagmembers);
2342 if (result != -1 && ld_tracing)
2344 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK)
2345 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) {
2348 if (obj->refcount == 0)
2352 /* Make list of init functions to call. */
2353 initlist_add_objects(obj, &obj->next, &initlist);
2358 * Bump the reference counts for objects on this DAG. If
2359 * this is the first dlopen() call for the object that was
2360 * already loaded as a dependency, initialize the dag
2366 if ((lo_flags & RTLD_LO_TRACE) != 0)
2369 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2370 obj->z_nodelete) && !obj->ref_nodel) {
2371 dbg("obj %s nodelete", obj->path);
2373 obj->z_nodelete = obj->ref_nodel = true;
2377 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2379 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2381 map_stacks_exec(&lockstate);
2383 /* Call the init functions. */
2384 objlist_call_init(&initlist, &lockstate);
2385 objlist_clear(&initlist);
2386 lock_release(rtld_bind_lock, &lockstate);
2389 trace_loaded_objects(obj);
2390 lock_release(rtld_bind_lock, &lockstate);
2395 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2399 const Obj_Entry *obj, *defobj;
2402 RtldLockState lockstate;
2407 symlook_init(&req, name);
2409 req.flags = flags | SYMLOOK_IN_PLT;
2410 req.lockstate = &lockstate;
2412 rlock_acquire(rtld_bind_lock, &lockstate);
2413 if (sigsetjmp(lockstate.env, 0) != 0)
2414 lock_upgrade(rtld_bind_lock, &lockstate);
2415 if (handle == NULL || handle == RTLD_NEXT ||
2416 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2418 if ((obj = obj_from_addr(retaddr)) == NULL) {
2419 _rtld_error("Cannot determine caller's shared object");
2420 lock_release(rtld_bind_lock, &lockstate);
2423 if (handle == NULL) { /* Just the caller's shared object. */
2424 res = symlook_obj(&req, obj);
2427 defobj = req.defobj_out;
2429 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2430 handle == RTLD_SELF) { /* ... caller included */
2431 if (handle == RTLD_NEXT)
2433 for (; obj != NULL; obj = obj->next) {
2434 res = symlook_obj(&req, obj);
2437 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2439 defobj = req.defobj_out;
2440 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2446 * Search the dynamic linker itself, and possibly resolve the
2447 * symbol from there. This is how the application links to
2448 * dynamic linker services such as dlopen.
2450 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2451 res = symlook_obj(&req, &obj_rtld);
2452 if (res == 0 && is_exported(req.sym_out)) {
2454 defobj = req.defobj_out;
2458 assert(handle == RTLD_DEFAULT);
2459 res = symlook_default(&req, obj);
2461 defobj = req.defobj_out;
2466 if ((obj = dlcheck(handle)) == NULL) {
2467 lock_release(rtld_bind_lock, &lockstate);
2471 donelist_init(&donelist);
2472 if (obj->mainprog) {
2473 /* Search main program and all libraries loaded by it. */
2474 res = symlook_list(&req, &list_main, &donelist);
2477 defobj = req.defobj_out;
2480 * We do not distinguish between 'main' object and
2481 * global scope. If symbol is not defined by objects
2482 * loaded at startup, continue search among
2483 * dynamically loaded objects with RTLD_GLOBAL scope.
2485 res = symlook_list(&req, &list_global, &donelist);
2488 defobj = req.defobj_out;
2494 /* Search the whole DAG rooted at the given object. */
2496 fake.obj = (Obj_Entry *)obj;
2498 res = symlook_needed(&req, &fake, &donelist);
2501 defobj = req.defobj_out;
2507 lock_release(rtld_bind_lock, &lockstate);
2510 * The value required by the caller is derived from the value
2511 * of the symbol. For the ia64 architecture, we need to
2512 * construct a function descriptor which the caller can use to
2513 * call the function with the right 'gp' value. For other
2514 * architectures and for non-functions, the value is simply
2515 * the relocated value of the symbol.
2517 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
2518 return (make_function_pointer(def, defobj));
2520 return (defobj->relocbase + def->st_value);
2523 _rtld_error("Undefined symbol \"%s\"", name);
2524 lock_release(rtld_bind_lock, &lockstate);
2529 dlsym(void *handle, const char *name)
2531 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2536 dlfunc(void *handle, const char *name)
2543 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
2549 dlvsym(void *handle, const char *name, const char *version)
2553 ventry.name = version;
2555 ventry.hash = elf_hash(version);
2557 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2562 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
2564 const Obj_Entry *obj;
2565 RtldLockState lockstate;
2567 rlock_acquire(rtld_bind_lock, &lockstate);
2568 obj = obj_from_addr(addr);
2570 _rtld_error("No shared object contains address");
2571 lock_release(rtld_bind_lock, &lockstate);
2574 rtld_fill_dl_phdr_info(obj, phdr_info);
2575 lock_release(rtld_bind_lock, &lockstate);
2580 dladdr(const void *addr, Dl_info *info)
2582 const Obj_Entry *obj;
2585 unsigned long symoffset;
2586 RtldLockState lockstate;
2588 rlock_acquire(rtld_bind_lock, &lockstate);
2589 obj = obj_from_addr(addr);
2591 _rtld_error("No shared object contains address");
2592 lock_release(rtld_bind_lock, &lockstate);
2595 info->dli_fname = obj->path;
2596 info->dli_fbase = obj->mapbase;
2597 info->dli_saddr = NULL;
2598 info->dli_sname = NULL;
2601 * Walk the symbol list looking for the symbol whose address is
2602 * closest to the address sent in.
2604 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
2605 def = obj->symtab + symoffset;
2608 * For skip the symbol if st_shndx is either SHN_UNDEF or
2611 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2615 * If the symbol is greater than the specified address, or if it
2616 * is further away from addr than the current nearest symbol,
2619 symbol_addr = obj->relocbase + def->st_value;
2620 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2623 /* Update our idea of the nearest symbol. */
2624 info->dli_sname = obj->strtab + def->st_name;
2625 info->dli_saddr = symbol_addr;
2628 if (info->dli_saddr == addr)
2631 lock_release(rtld_bind_lock, &lockstate);
2636 dlinfo(void *handle, int request, void *p)
2638 const Obj_Entry *obj;
2639 RtldLockState lockstate;
2642 rlock_acquire(rtld_bind_lock, &lockstate);
2644 if (handle == NULL || handle == RTLD_SELF) {
2647 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2648 if ((obj = obj_from_addr(retaddr)) == NULL)
2649 _rtld_error("Cannot determine caller's shared object");
2651 obj = dlcheck(handle);
2654 lock_release(rtld_bind_lock, &lockstate);
2660 case RTLD_DI_LINKMAP:
2661 *((struct link_map const **)p) = &obj->linkmap;
2663 case RTLD_DI_ORIGIN:
2664 error = rtld_dirname(obj->path, p);
2667 case RTLD_DI_SERINFOSIZE:
2668 case RTLD_DI_SERINFO:
2669 error = do_search_info(obj, request, (struct dl_serinfo *)p);
2673 _rtld_error("Invalid request %d passed to dlinfo()", request);
2677 lock_release(rtld_bind_lock, &lockstate);
2683 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
2686 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
2687 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
2688 STAILQ_FIRST(&obj->names)->name : obj->path;
2689 phdr_info->dlpi_phdr = obj->phdr;
2690 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
2691 phdr_info->dlpi_tls_modid = obj->tlsindex;
2692 phdr_info->dlpi_tls_data = obj->tlsinit;
2693 phdr_info->dlpi_adds = obj_loads;
2694 phdr_info->dlpi_subs = obj_loads - obj_count;
2698 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
2700 struct dl_phdr_info phdr_info;
2701 const Obj_Entry *obj;
2702 RtldLockState bind_lockstate, phdr_lockstate;
2705 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
2706 rlock_acquire(rtld_bind_lock, &bind_lockstate);
2710 for (obj = obj_list; obj != NULL; obj = obj->next) {
2711 rtld_fill_dl_phdr_info(obj, &phdr_info);
2712 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
2716 lock_release(rtld_bind_lock, &bind_lockstate);
2717 lock_release(rtld_phdr_lock, &phdr_lockstate);
2722 struct fill_search_info_args {
2725 Dl_serinfo *serinfo;
2726 Dl_serpath *serpath;
2731 fill_search_info(const char *dir, size_t dirlen, void *param)
2733 struct fill_search_info_args *arg;
2737 if (arg->request == RTLD_DI_SERINFOSIZE) {
2738 arg->serinfo->dls_cnt ++;
2739 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
2741 struct dl_serpath *s_entry;
2743 s_entry = arg->serpath;
2744 s_entry->dls_name = arg->strspace;
2745 s_entry->dls_flags = arg->flags;
2747 strncpy(arg->strspace, dir, dirlen);
2748 arg->strspace[dirlen] = '\0';
2750 arg->strspace += dirlen + 1;
2758 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2760 struct dl_serinfo _info;
2761 struct fill_search_info_args args;
2763 args.request = RTLD_DI_SERINFOSIZE;
2764 args.serinfo = &_info;
2766 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2769 path_enumerate(ld_library_path, fill_search_info, &args);
2770 path_enumerate(obj->rpath, fill_search_info, &args);
2771 path_enumerate(gethints(), fill_search_info, &args);
2772 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
2775 if (request == RTLD_DI_SERINFOSIZE) {
2776 info->dls_size = _info.dls_size;
2777 info->dls_cnt = _info.dls_cnt;
2781 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
2782 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
2786 args.request = RTLD_DI_SERINFO;
2787 args.serinfo = info;
2788 args.serpath = &info->dls_serpath[0];
2789 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
2791 args.flags = LA_SER_LIBPATH;
2792 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
2795 args.flags = LA_SER_RUNPATH;
2796 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
2799 args.flags = LA_SER_CONFIG;
2800 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
2803 args.flags = LA_SER_DEFAULT;
2804 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
2810 rtld_dirname(const char *path, char *bname)
2814 /* Empty or NULL string gets treated as "." */
2815 if (path == NULL || *path == '\0') {
2821 /* Strip trailing slashes */
2822 endp = path + strlen(path) - 1;
2823 while (endp > path && *endp == '/')
2826 /* Find the start of the dir */
2827 while (endp > path && *endp != '/')
2830 /* Either the dir is "/" or there are no slashes */
2832 bname[0] = *endp == '/' ? '/' : '.';
2838 } while (endp > path && *endp == '/');
2841 if (endp - path + 2 > PATH_MAX)
2843 _rtld_error("Filename is too long: %s", path);
2847 strncpy(bname, path, endp - path + 1);
2848 bname[endp - path + 1] = '\0';
2853 rtld_dirname_abs(const char *path, char *base)
2855 char base_rel[PATH_MAX];
2857 if (rtld_dirname(path, base) == -1)
2861 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
2862 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
2863 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
2865 strcpy(base, base_rel);
2870 linkmap_add(Obj_Entry *obj)
2872 struct link_map *l = &obj->linkmap;
2873 struct link_map *prev;
2875 obj->linkmap.l_name = obj->path;
2876 obj->linkmap.l_addr = obj->mapbase;
2877 obj->linkmap.l_ld = obj->dynamic;
2879 /* GDB needs load offset on MIPS to use the symbols */
2880 obj->linkmap.l_offs = obj->relocbase;
2883 if (r_debug.r_map == NULL) {
2889 * Scan to the end of the list, but not past the entry for the
2890 * dynamic linker, which we want to keep at the very end.
2892 for (prev = r_debug.r_map;
2893 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
2894 prev = prev->l_next)
2897 /* Link in the new entry. */
2899 l->l_next = prev->l_next;
2900 if (l->l_next != NULL)
2901 l->l_next->l_prev = l;
2906 linkmap_delete(Obj_Entry *obj)
2908 struct link_map *l = &obj->linkmap;
2910 if (l->l_prev == NULL) {
2911 if ((r_debug.r_map = l->l_next) != NULL)
2912 l->l_next->l_prev = NULL;
2916 if ((l->l_prev->l_next = l->l_next) != NULL)
2917 l->l_next->l_prev = l->l_prev;
2921 * Function for the debugger to set a breakpoint on to gain control.
2923 * The two parameters allow the debugger to easily find and determine
2924 * what the runtime loader is doing and to whom it is doing it.
2926 * When the loadhook trap is hit (r_debug_state, set at program
2927 * initialization), the arguments can be found on the stack:
2929 * +8 struct link_map *m
2930 * +4 struct r_debug *rd
2934 r_debug_state(struct r_debug* rd, struct link_map *m)
2937 * The following is a hack to force the compiler to emit calls to
2938 * this function, even when optimizing. If the function is empty,
2939 * the compiler is not obliged to emit any code for calls to it,
2940 * even when marked __noinline. However, gdb depends on those
2943 __asm __volatile("" : : : "memory");
2947 * Get address of the pointer variable in the main program.
2949 static const void **
2950 get_program_var_addr(const char *name)
2952 const Obj_Entry *obj;
2955 symlook_init(&req, name);
2956 for (obj = obj_main; obj != NULL; obj = obj->next) {
2957 if (symlook_obj(&req, obj) == 0) {
2958 return ((const void **)(req.defobj_out->relocbase +
2959 req.sym_out->st_value));
2966 * Set a pointer variable in the main program to the given value. This
2967 * is used to set key variables such as "environ" before any of the
2968 * init functions are called.
2971 set_program_var(const char *name, const void *value)
2975 if ((addr = get_program_var_addr(name)) != NULL) {
2976 dbg("\"%s\": *%p <-- %p", name, addr, value);
2982 * This is a special version of getenv which is far more efficient
2983 * at finding LD_ environment vars.
2987 _getenv_ld(const char *id)
2991 int idlen = strlen(id);
2993 if (ld_index == LD_ARY_CACHE)
2995 if (ld_index == 0) {
2996 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) {
2997 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_')
3004 for (i = ld_index - 1; i >= 0; --i) {
3005 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=')
3006 return(ld_ary[i] + idlen + 1);
3012 * Given a symbol name in a referencing object, find the corresponding
3013 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3014 * no definition was found. Returns a pointer to the Obj_Entry of the
3015 * defining object via the reference parameter DEFOBJ_OUT.
3018 symlook_default(SymLook *req, const Obj_Entry *refobj)
3022 const Obj_Entry *defobj;
3023 const Objlist_Entry *elm;
3028 donelist_init(&donelist);
3029 symlook_init_from_req(&req1, req);
3031 /* Look first in the referencing object if linked symbolically. */
3032 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3033 res = symlook_obj(&req1, refobj);
3036 defobj = req1.defobj_out;
3037 assert(defobj != NULL);
3041 /* Search all objects loaded at program start up. */
3042 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3043 res = symlook_list(&req1, &list_main, &donelist);
3045 (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3047 defobj = req1.defobj_out;
3048 assert(defobj != NULL);
3052 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3053 STAILQ_FOREACH(elm, &list_global, link) {
3054 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
3056 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3058 (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3060 defobj = req1.defobj_out;
3061 assert(defobj != NULL);
3065 /* Search all dlopened DAGs containing the referencing object. */
3066 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3067 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
3069 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3071 (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3073 defobj = req1.defobj_out;
3074 assert(defobj != NULL);
3079 * Search the dynamic linker itself, and possibly resolve the
3080 * symbol from there. This is how the application links to
3081 * dynamic linker services such as dlopen. Only the values listed
3082 * in the "exports" array can be resolved from the dynamic linker.
3084 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3085 res = symlook_obj(&req1, &obj_rtld);
3086 if (res == 0 && is_exported(req1.sym_out)) {
3088 defobj = req1.defobj_out;
3089 assert(defobj != NULL);
3094 assert(defobj != NULL);
3095 req->defobj_out = defobj;
3103 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3106 const Obj_Entry *defobj;
3107 const Objlist_Entry *elm;
3113 STAILQ_FOREACH(elm, objlist, link) {
3114 if (donelist_check(dlp, elm->obj))
3116 symlook_init_from_req(&req1, req);
3117 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3118 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3120 defobj = req1.defobj_out;
3121 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3128 req->defobj_out = defobj;
3135 * Search the symbol table of a shared object and all objects needed
3136 * by it for a symbol of the given name. Search order is
3137 * breadth-first. Returns a pointer to the symbol, or NULL if no
3138 * definition was found.
3141 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3143 const Elf_Sym *def, *def_w;
3144 const Needed_Entry *n;
3145 const Obj_Entry *defobj, *defobj1;
3151 symlook_init_from_req(&req1, req);
3152 for (n = needed; n != NULL; n = n->next) {
3153 if (n->obj == NULL || donelist_check(dlp, n->obj) ||
3154 (res = symlook_obj(&req1, n->obj)) != 0)
3157 defobj = req1.defobj_out;
3158 if (ELF_ST_BIND(def->st_info) != STB_WEAK) {
3159 req->defobj_out = defobj;
3165 * There we come when either symbol definition is not found in
3166 * directly needed objects, or found symbol is weak.
3168 for (n = needed; n != NULL; n = n->next) {
3171 res = symlook_needed(&req1, n->obj->needed, dlp);
3174 def_w = req1.sym_out;
3175 defobj1 = req1.defobj_out;
3176 if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) {
3180 if (ELF_ST_BIND(def_w->st_info) != STB_WEAK)
3185 req->defobj_out = defobj;
3192 * Search the symbol table of a single shared object for a symbol of
3193 * the given name and version, if requested. Returns a pointer to the
3194 * symbol, or NULL if no definition was found. If the object is
3195 * filter, return filtered symbol from filtee.
3197 * The symbol's hash value is passed in for efficiency reasons; that
3198 * eliminates many recomputations of the hash value.
3201 symlook_obj(SymLook *req, const Obj_Entry *obj)
3207 mres = symlook_obj1(req, obj);
3209 if (obj->needed_filtees != NULL) {
3210 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3211 donelist_init(&donelist);
3212 symlook_init_from_req(&req1, req);
3213 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3215 req->sym_out = req1.sym_out;
3216 req->defobj_out = req1.defobj_out;
3220 if (obj->needed_aux_filtees != NULL) {
3221 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3222 donelist_init(&donelist);
3223 symlook_init_from_req(&req1, req);
3224 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3226 req->sym_out = req1.sym_out;
3227 req->defobj_out = req1.defobj_out;
3236 symlook_obj1(SymLook *req, const Obj_Entry *obj)
3238 unsigned long symnum;
3239 const Elf_Sym *vsymp;
3243 if (obj->buckets == NULL)
3248 symnum = obj->buckets[req->hash % obj->nbuckets];
3250 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3251 const Elf_Sym *symp;
3254 if (symnum >= obj->nchains)
3255 return (ESRCH); /* Bad object */
3257 symp = obj->symtab + symnum;
3258 strp = obj->strtab + symp->st_name;
3260 switch (ELF_ST_TYPE(symp->st_info)) {
3264 if (symp->st_value == 0)
3268 if (symp->st_shndx != SHN_UNDEF)
3270 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3271 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3277 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3280 if (req->ventry == NULL) {
3281 if (obj->versyms != NULL) {
3282 verndx = VER_NDX(obj->versyms[symnum]);
3283 if (verndx > obj->vernum) {
3284 _rtld_error("%s: symbol %s references wrong version %d",
3285 obj->path, obj->strtab + symnum, verndx);
3289 * If we are not called from dlsym (i.e. this is a normal
3290 * relocation from unversioned binary), accept the symbol
3291 * immediately if it happens to have first version after
3292 * this shared object became versioned. Otherwise, if
3293 * symbol is versioned and not hidden, remember it. If it
3294 * is the only symbol with this name exported by the
3295 * shared object, it will be returned as a match at the
3296 * end of the function. If symbol is global (verndx < 2)
3297 * accept it unconditionally.
3299 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3300 verndx == VER_NDX_GIVEN) {
3301 req->sym_out = symp;
3302 req->defobj_out = obj;
3305 else if (verndx >= VER_NDX_GIVEN) {
3306 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
3314 req->sym_out = symp;
3315 req->defobj_out = obj;
3318 if (obj->versyms == NULL) {
3319 if (object_match_name(obj, req->ventry->name)) {
3320 _rtld_error("%s: object %s should provide version %s for "
3321 "symbol %s", obj_rtld.path, obj->path,
3322 req->ventry->name, obj->strtab + symnum);
3326 verndx = VER_NDX(obj->versyms[symnum]);
3327 if (verndx > obj->vernum) {
3328 _rtld_error("%s: symbol %s references wrong version %d",
3329 obj->path, obj->strtab + symnum, verndx);
3332 if (obj->vertab[verndx].hash != req->ventry->hash ||
3333 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3335 * Version does not match. Look if this is a global symbol
3336 * and if it is not hidden. If global symbol (verndx < 2)
3337 * is available, use it. Do not return symbol if we are
3338 * called by dlvsym, because dlvsym looks for a specific
3339 * version and default one is not what dlvsym wants.
3341 if ((req->flags & SYMLOOK_DLSYM) ||
3342 (obj->versyms[symnum] & VER_NDX_HIDDEN) ||
3343 (verndx >= VER_NDX_GIVEN))
3347 req->sym_out = symp;
3348 req->defobj_out = obj;
3353 req->sym_out = vsymp;
3354 req->defobj_out = obj;
3361 trace_loaded_objects(Obj_Entry *obj)
3363 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3366 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3369 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3370 fmt1 = "\t%o => %p (%x)\n";
3372 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3373 fmt2 = "\t%o (%x)\n";
3375 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL");
3377 for (; obj; obj = obj->next) {
3378 Needed_Entry *needed;
3382 if (list_containers && obj->needed != NULL)
3383 rtld_printf("%s:\n", obj->path);
3384 for (needed = obj->needed; needed; needed = needed->next) {
3385 if (needed->obj != NULL) {
3386 if (needed->obj->traced && !list_containers)
3388 needed->obj->traced = true;
3389 path = needed->obj->path;
3393 name = (char *)obj->strtab + needed->name;
3394 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3396 fmt = is_lib ? fmt1 : fmt2;
3397 while ((c = *fmt++) != '\0') {
3423 rtld_putstr(main_local);
3426 rtld_putstr(obj_main->path);
3435 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
3448 * Unload a dlopened object and its dependencies from memory and from
3449 * our data structures. It is assumed that the DAG rooted in the
3450 * object has already been unreferenced, and that the object has a
3451 * reference count of 0.
3454 unload_object(Obj_Entry *root)
3459 assert(root->refcount == 0);
3462 * Pass over the DAG removing unreferenced objects from
3463 * appropriate lists.
3465 unlink_object(root);
3467 /* Unmap all objects that are no longer referenced. */
3468 linkp = &obj_list->next;
3469 while ((obj = *linkp) != NULL) {
3470 if (obj->refcount == 0) {
3471 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3473 dbg("unloading \"%s\"", obj->path);
3474 unload_filtees(root);
3475 munmap(obj->mapbase, obj->mapsize);
3476 linkmap_delete(obj);
3487 unlink_object(Obj_Entry *root)
3491 if (root->refcount == 0) {
3492 /* Remove the object from the RTLD_GLOBAL list. */
3493 objlist_remove(&list_global, root);
3495 /* Remove the object from all objects' DAG lists. */
3496 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3497 objlist_remove(&elm->obj->dldags, root);
3498 if (elm->obj != root)
3499 unlink_object(elm->obj);
3505 ref_dag(Obj_Entry *root)
3509 assert(root->dag_inited);
3510 STAILQ_FOREACH(elm, &root->dagmembers, link)
3511 elm->obj->refcount++;
3515 unref_dag(Obj_Entry *root)
3519 assert(root->dag_inited);
3520 STAILQ_FOREACH(elm, &root->dagmembers, link)
3521 elm->obj->refcount--;
3525 * Common code for MD __tls_get_addr().
3528 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
3530 Elf_Addr* dtv = *dtvp;
3531 RtldLockState lockstate;
3533 /* Check dtv generation in case new modules have arrived */
3534 if (dtv[0] != tls_dtv_generation) {
3538 wlock_acquire(rtld_bind_lock, &lockstate);
3539 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3541 if (to_copy > tls_max_index)
3542 to_copy = tls_max_index;
3543 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
3544 newdtv[0] = tls_dtv_generation;
3545 newdtv[1] = tls_max_index;
3547 lock_release(rtld_bind_lock, &lockstate);
3548 dtv = *dtvp = newdtv;
3551 /* Dynamically allocate module TLS if necessary */
3552 if (!dtv[index + 1]) {
3553 /* Signal safe, wlock will block out signals. */
3554 wlock_acquire(rtld_bind_lock, &lockstate);
3555 if (!dtv[index + 1])
3556 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
3557 lock_release(rtld_bind_lock, &lockstate);
3559 return (void*) (dtv[index + 1] + offset);
3562 #if defined(RTLD_STATIC_TLS_VARIANT_II)
3565 * Allocate the static TLS area. Return a pointer to the TCB. The
3566 * static area is based on negative offsets relative to the tcb.
3568 * The TCB contains an errno pointer for the system call layer, but because
3569 * we are the RTLD we really have no idea how the caller was compiled so
3570 * the information has to be passed in. errno can either be:
3572 * type 0 errno is a simple non-TLS global pointer.
3573 * (special case for e.g. libc_rtld)
3574 * type 1 errno accessed by GOT entry (dynamically linked programs)
3575 * type 2 errno accessed by %gs:OFFSET (statically linked programs)
3578 allocate_tls(Obj_Entry *objs)
3583 struct tls_tcb *tcb;
3588 * Allocate the new TCB. static TLS storage is placed just before the
3589 * TCB to support the %gs:OFFSET (negative offset) model.
3591 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
3592 ~RTLD_STATIC_TLS_ALIGN_MASK;
3593 tcb = malloc(data_size + sizeof(*tcb));
3594 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */
3596 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr);
3597 dtv = malloc(dtv_size);
3598 bzero(dtv, dtv_size);
3600 #ifdef RTLD_TCB_HAS_SELF_POINTER
3601 tcb->tcb_self = tcb;
3604 tcb->tcb_pthread = NULL;
3606 dtv[0] = tls_dtv_generation;
3607 dtv[1] = tls_max_index;
3609 for (obj = objs; obj; obj = obj->next) {
3610 if (obj->tlsoffset) {
3611 addr = (Elf_Addr)tcb - obj->tlsoffset;
3612 memset((void *)(addr + obj->tlsinitsize),
3613 0, obj->tlssize - obj->tlsinitsize);
3615 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3616 dtv[obj->tlsindex + 1] = addr;
3623 free_tls(struct tls_tcb *tcb)
3627 Elf_Addr tls_start, tls_end;
3630 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
3631 ~RTLD_STATIC_TLS_ALIGN_MASK;
3635 tls_end = (Elf_Addr)tcb;
3636 tls_start = (Elf_Addr)tcb - data_size;
3637 for (i = 0; i < dtv_size; i++) {
3638 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) {
3639 free((void *)dtv[i+2]);
3643 free((void*) tls_start);
3647 #error "Unsupported TLS layout"
3651 * Allocate TLS block for module with given index.
3654 allocate_module_tls(int index)
3659 for (obj = obj_list; obj; obj = obj->next) {
3660 if (obj->tlsindex == index)
3664 _rtld_error("Can't find module with TLS index %d", index);
3668 p = malloc(obj->tlssize);
3670 _rtld_error("Cannot allocate TLS block for index %d", index);
3673 memcpy(p, obj->tlsinit, obj->tlsinitsize);
3674 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
3680 allocate_tls_offset(Obj_Entry *obj)
3687 if (obj->tlssize == 0) {
3688 obj->tls_done = true;
3692 if (obj->tlsindex == 1)
3693 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
3695 off = calculate_tls_offset(tls_last_offset, tls_last_size,
3696 obj->tlssize, obj->tlsalign);
3699 * If we have already fixed the size of the static TLS block, we
3700 * must stay within that size. When allocating the static TLS, we
3701 * leave a small amount of space spare to be used for dynamically
3702 * loading modules which use static TLS.
3704 if (tls_static_space) {
3705 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
3709 tls_last_offset = obj->tlsoffset = off;
3710 tls_last_size = obj->tlssize;
3711 obj->tls_done = true;
3717 free_tls_offset(Obj_Entry *obj)
3719 #ifdef RTLD_STATIC_TLS_VARIANT_II
3721 * If we were the last thing to allocate out of the static TLS
3722 * block, we give our space back to the 'allocator'. This is a
3723 * simplistic workaround to allow libGL.so.1 to be loaded and
3724 * unloaded multiple times. We only handle the Variant II
3725 * mechanism for now - this really needs a proper allocator.
3727 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
3728 == calculate_tls_end(tls_last_offset, tls_last_size)) {
3729 tls_last_offset -= obj->tlssize;
3736 _rtld_allocate_tls(void)
3738 struct tls_tcb *new_tcb;
3739 RtldLockState lockstate;
3741 wlock_acquire(rtld_bind_lock, &lockstate);
3742 new_tcb = allocate_tls(obj_list);
3743 lock_release(rtld_bind_lock, &lockstate);
3748 _rtld_free_tls(struct tls_tcb *tcb)
3750 RtldLockState lockstate;
3752 wlock_acquire(rtld_bind_lock, &lockstate);
3754 lock_release(rtld_bind_lock, &lockstate);
3758 object_add_name(Obj_Entry *obj, const char *name)
3764 entry = malloc(sizeof(Name_Entry) + len);
3766 if (entry != NULL) {
3767 strcpy(entry->name, name);
3768 STAILQ_INSERT_TAIL(&obj->names, entry, link);
3773 object_match_name(const Obj_Entry *obj, const char *name)
3777 STAILQ_FOREACH(entry, &obj->names, link) {
3778 if (strcmp(name, entry->name) == 0)
3785 locate_dependency(const Obj_Entry *obj, const char *name)
3787 const Objlist_Entry *entry;
3788 const Needed_Entry *needed;
3790 STAILQ_FOREACH(entry, &list_main, link) {
3791 if (object_match_name(entry->obj, name))
3795 for (needed = obj->needed; needed != NULL; needed = needed->next) {
3796 if (strcmp(obj->strtab + needed->name, name) == 0 ||
3797 (needed->obj != NULL && object_match_name(needed->obj, name))) {
3799 * If there is DT_NEEDED for the name we are looking for,
3800 * we are all set. Note that object might not be found if
3801 * dependency was not loaded yet, so the function can
3802 * return NULL here. This is expected and handled
3803 * properly by the caller.
3805 return (needed->obj);
3808 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
3814 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
3815 const Elf_Vernaux *vna)
3817 const Elf_Verdef *vd;
3818 const char *vername;
3820 vername = refobj->strtab + vna->vna_name;
3821 vd = depobj->verdef;
3823 _rtld_error("%s: version %s required by %s not defined",
3824 depobj->path, vername, refobj->path);
3828 if (vd->vd_version != VER_DEF_CURRENT) {
3829 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3830 depobj->path, vd->vd_version);
3833 if (vna->vna_hash == vd->vd_hash) {
3834 const Elf_Verdaux *aux = (const Elf_Verdaux *)
3835 ((char *)vd + vd->vd_aux);
3836 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
3839 if (vd->vd_next == 0)
3841 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3843 if (vna->vna_flags & VER_FLG_WEAK)
3845 _rtld_error("%s: version %s required by %s not found",
3846 depobj->path, vername, refobj->path);
3851 rtld_verify_object_versions(Obj_Entry *obj)
3853 const Elf_Verneed *vn;
3854 const Elf_Verdef *vd;
3855 const Elf_Verdaux *vda;
3856 const Elf_Vernaux *vna;
3857 const Obj_Entry *depobj;
3858 int maxvernum, vernum;
3862 * Walk over defined and required version records and figure out
3863 * max index used by any of them. Do very basic sanity checking
3867 while (vn != NULL) {
3868 if (vn->vn_version != VER_NEED_CURRENT) {
3869 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
3870 obj->path, vn->vn_version);
3873 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3875 vernum = VER_NEED_IDX(vna->vna_other);
3876 if (vernum > maxvernum)
3878 if (vna->vna_next == 0)
3880 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3882 if (vn->vn_next == 0)
3884 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3888 while (vd != NULL) {
3889 if (vd->vd_version != VER_DEF_CURRENT) {
3890 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3891 obj->path, vd->vd_version);
3894 vernum = VER_DEF_IDX(vd->vd_ndx);
3895 if (vernum > maxvernum)
3897 if (vd->vd_next == 0)
3899 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3906 * Store version information in array indexable by version index.
3907 * Verify that object version requirements are satisfied along the
3910 obj->vernum = maxvernum + 1;
3911 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry));
3914 while (vd != NULL) {
3915 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
3916 vernum = VER_DEF_IDX(vd->vd_ndx);
3917 assert(vernum <= maxvernum);
3918 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
3919 obj->vertab[vernum].hash = vd->vd_hash;
3920 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
3921 obj->vertab[vernum].file = NULL;
3922 obj->vertab[vernum].flags = 0;
3924 if (vd->vd_next == 0)
3926 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3930 while (vn != NULL) {
3931 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
3934 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3936 if (check_object_provided_version(obj, depobj, vna))
3938 vernum = VER_NEED_IDX(vna->vna_other);
3939 assert(vernum <= maxvernum);
3940 obj->vertab[vernum].hash = vna->vna_hash;
3941 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
3942 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
3943 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
3944 VER_INFO_HIDDEN : 0;
3945 if (vna->vna_next == 0)
3947 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3949 if (vn->vn_next == 0)
3951 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3957 rtld_verify_versions(const Objlist *objlist)
3959 Objlist_Entry *entry;
3963 STAILQ_FOREACH(entry, objlist, link) {
3965 * Skip dummy objects or objects that have their version requirements
3968 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
3970 if (rtld_verify_object_versions(entry->obj) == -1) {
3972 if (ld_tracing == NULL)
3976 if (rc == 0 || ld_tracing != NULL)
3977 rc = rtld_verify_object_versions(&obj_rtld);
3982 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
3987 vernum = VER_NDX(obj->versyms[symnum]);
3988 if (vernum >= obj->vernum) {
3989 _rtld_error("%s: symbol %s has wrong verneed value %d",
3990 obj->path, obj->strtab + symnum, vernum);
3991 } else if (obj->vertab[vernum].hash != 0) {
3992 return &obj->vertab[vernum];
3999 _rtld_get_stack_prot(void)
4002 return (stack_prot);
4006 map_stacks_exec(RtldLockState *lockstate)
4010 * Stack protection must be implemented in the kernel before the dynamic
4011 * linker can handle PT_GNU_STACK sections.
4012 * The following is the FreeBSD implementation of map_stacks_exec()
4013 * void (*thr_map_stacks_exec)(void);
4015 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4017 * thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4018 * get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4019 * if (thr_map_stacks_exec != NULL) {
4020 * stack_prot |= PROT_EXEC;
4021 * thr_map_stacks_exec();
4027 symlook_init(SymLook *dst, const char *name)
4030 bzero(dst, sizeof(*dst));
4032 dst->hash = elf_hash(name);
4036 symlook_init_from_req(SymLook *dst, const SymLook *src)
4039 dst->name = src->name;
4040 dst->hash = src->hash;
4041 dst->ventry = src->ventry;
4042 dst->flags = src->flags;
4043 dst->defobj_out = NULL;
4044 dst->sym_out = NULL;
4045 dst->lockstate = src->lockstate;
4048 #ifdef ENABLE_OSRELDATE
4050 * Overrides for libc_pic-provided functions.
4054 __getosreldate(void)
4064 oid[1] = KERN_OSRELDATE;
4066 len = sizeof(osrel);
4067 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4068 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4075 * No unresolved symbols for rtld.
4078 __pthread_cxa_finalize(struct dl_phdr_info *a)