2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
38 #error "GCC is needed to compile this file"
41 #include <sys/param.h>
42 #include <sys/mount.h>
45 #include <sys/sysctl.h>
47 #include <sys/utsname.h>
48 #include <sys/ktrace.h>
49 #include <sys/resident.h>
52 #include <machine/tls.h>
67 #include "rtld_printf.h"
70 #define PATH_RTLD "/usr/libexec/ld-elf.so.2"
71 #define LD_ARY_CACHE 16
74 typedef void (*func_ptr_type)();
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 * Function declarations.
80 static const char *_getenv_ld(const char *id);
81 static void die(void) __dead2;
82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
83 const Elf_Dyn **, const Elf_Dyn **);
84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
86 static void digest_dynamic(Obj_Entry *, int);
87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
88 static Obj_Entry *dlcheck(void *);
89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
90 int lo_flags, int mode, RtldLockState *lockstate);
91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
93 static bool donelist_check(DoneList *, const Obj_Entry *);
94 static void errmsg_restore(char *);
95 static char *errmsg_save(void);
96 static void *fill_search_info(const char *, size_t, void *);
97 static char *find_library(const char *, const Obj_Entry *);
98 static const char *gethints(bool);
99 static void init_dag(Obj_Entry *);
100 static void init_rtld(caddr_t, Elf_Auxinfo **);
101 static void initlist_add_neededs(Needed_Entry *, Objlist *);
102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
103 static bool is_exported(const Elf_Sym *);
104 static void linkmap_add(Obj_Entry *);
105 static void linkmap_delete(Obj_Entry *);
106 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
107 static void unload_filtees(Obj_Entry *);
108 static int load_needed_objects(Obj_Entry *, int);
109 static int load_preload_objects(void);
110 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
111 static void map_stacks_exec(RtldLockState *);
112 static Obj_Entry *obj_from_addr(const void *);
113 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
114 static void objlist_call_init(Objlist *, RtldLockState *);
115 static void objlist_clear(Objlist *);
116 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
117 static void objlist_init(Objlist *);
118 static void objlist_push_head(Objlist *, Obj_Entry *);
119 static void objlist_push_tail(Objlist *, Obj_Entry *);
120 static void objlist_remove(Objlist *, Obj_Entry *);
121 static void *path_enumerate(const char *, path_enum_proc, void *);
122 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
123 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
124 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
125 int flags, RtldLockState *lockstate);
126 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
128 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
129 int flags, RtldLockState *lockstate);
130 static int rtld_dirname(const char *, char *);
131 static int rtld_dirname_abs(const char *, char *);
132 static void *rtld_dlopen(const char *name, int fd, int mode);
133 static void rtld_exit(void);
134 static char *search_library_path(const char *, const char *);
135 static const void **get_program_var_addr(const char *, RtldLockState *);
136 static void set_program_var(const char *, const void *);
137 static int symlook_default(SymLook *, const Obj_Entry *refobj);
138 static int symlook_global(SymLook *, DoneList *);
139 static void symlook_init_from_req(SymLook *, const SymLook *);
140 static int symlook_list(SymLook *, const Objlist *, DoneList *);
141 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
142 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
143 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
144 static void trace_loaded_objects(Obj_Entry *);
145 static void unlink_object(Obj_Entry *);
146 static void unload_object(Obj_Entry *);
147 static void unref_dag(Obj_Entry *);
148 static void ref_dag(Obj_Entry *);
149 static char *origin_subst_one(char *, const char *, const char *, bool);
150 static char *origin_subst(char *, const char *);
151 static void preinitialize_main_object (void);
152 static int rtld_verify_versions(const Objlist *);
153 static int rtld_verify_object_versions(Obj_Entry *);
154 static void object_add_name(Obj_Entry *, const char *);
155 static int object_match_name(const Obj_Entry *, const char *);
156 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
157 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
158 struct dl_phdr_info *phdr_info);
159 static uint_fast32_t gnu_hash (const char *);
160 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
161 const unsigned long);
163 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
168 static char *error_message; /* Message for dlerror(), or NULL */
169 struct r_debug r_debug; /* for GDB; */
170 static bool libmap_disable; /* Disable libmap */
171 static bool ld_loadfltr; /* Immediate filters processing */
172 static char *libmap_override; /* Maps to use in addition to libmap.conf */
173 static bool trust; /* False for setuid and setgid programs */
174 static bool dangerous_ld_env; /* True if environment variables have been
175 used to affect the libraries loaded */
176 static const char *ld_bind_now; /* Environment variable for immediate binding */
177 static const char *ld_debug; /* Environment variable for debugging */
178 static const char *ld_library_path; /* Environment variable for search path */
179 static char *ld_preload; /* Environment variable for libraries to
181 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
182 static const char *ld_tracing; /* Called from ldd to print libs */
183 static const char *ld_utrace; /* Use utrace() to log events. */
184 static int (*rtld_functrace)( /* Optional function call tracing hook */
185 const char *caller_obj,
186 const char *callee_obj,
187 const char *callee_func,
189 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */
190 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
191 static Obj_Entry **obj_tail; /* Link field of last object in list */
192 static Obj_Entry **preload_tail;
193 static Obj_Entry *obj_main; /* The main program shared object */
194 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
195 static unsigned int obj_count; /* Number of objects in obj_list */
196 static unsigned int obj_loads; /* Number of objects in obj_list */
198 static int ld_resident; /* Non-zero if resident */
199 static const char *ld_ary[LD_ARY_CACHE];
201 static Objlist initlist;
203 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
204 STAILQ_HEAD_INITIALIZER(list_global);
205 static Objlist list_main = /* Objects loaded at program startup */
206 STAILQ_HEAD_INITIALIZER(list_main);
207 static Objlist list_fini = /* Objects needing fini() calls */
208 STAILQ_HEAD_INITIALIZER(list_fini);
210 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
212 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
214 extern Elf_Dyn _DYNAMIC;
215 #pragma weak _DYNAMIC
216 #ifndef RTLD_IS_DYNAMIC
217 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
220 #ifdef ENABLE_OSRELDATE
224 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
225 static int max_stack_flags;
228 * These are the functions the dynamic linker exports to application
229 * programs. They are the only symbols the dynamic linker is willing
230 * to export from itself.
232 static func_ptr_type exports[] = {
233 (func_ptr_type) &_rtld_error,
234 (func_ptr_type) &dlclose,
235 (func_ptr_type) &dlerror,
236 (func_ptr_type) &dlopen,
237 (func_ptr_type) &fdlopen,
238 (func_ptr_type) &dlfunc,
239 (func_ptr_type) &dlsym,
240 (func_ptr_type) &dlvsym,
241 (func_ptr_type) &dladdr,
242 (func_ptr_type) &dlinfo,
243 (func_ptr_type) &dl_iterate_phdr,
245 (func_ptr_type) &___tls_get_addr,
247 (func_ptr_type) &__tls_get_addr,
248 (func_ptr_type) &__tls_get_addr_tcb,
249 (func_ptr_type) &_rtld_allocate_tls,
250 (func_ptr_type) &_rtld_free_tls,
251 (func_ptr_type) &_rtld_call_init,
252 (func_ptr_type) &_rtld_thread_init,
253 (func_ptr_type) &_rtld_addr_phdr,
254 (func_ptr_type) &_rtld_get_stack_prot,
259 * Global declarations normally provided by crt1. The dynamic linker is
260 * not built with crt1, so we have to provide them ourselves.
266 * Used to pass argc, argv to init functions.
272 * Globals to control TLS allocation.
274 size_t tls_last_offset; /* Static TLS offset of last module */
275 size_t tls_last_size; /* Static TLS size of last module */
276 size_t tls_static_space; /* Static TLS space allocated */
277 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
278 int tls_max_index = 1; /* Largest module index allocated */
281 * Fill in a DoneList with an allocation large enough to hold all of
282 * the currently-loaded objects. Keep this as a macro since it calls
283 * alloca and we want that to occur within the scope of the caller.
285 #define donelist_init(dlp) \
286 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
287 assert((dlp)->objs != NULL), \
288 (dlp)->num_alloc = obj_count, \
291 #define UTRACE_DLOPEN_START 1
292 #define UTRACE_DLOPEN_STOP 2
293 #define UTRACE_DLCLOSE_START 3
294 #define UTRACE_DLCLOSE_STOP 4
295 #define UTRACE_LOAD_OBJECT 5
296 #define UTRACE_UNLOAD_OBJECT 6
297 #define UTRACE_ADD_RUNDEP 7
298 #define UTRACE_PRELOAD_FINISHED 8
299 #define UTRACE_INIT_CALL 9
300 #define UTRACE_FINI_CALL 10
303 char sig[4]; /* 'RTLD' */
306 void *mapbase; /* Used for 'parent' and 'init/fini' */
308 int refcnt; /* Used for 'mode' */
309 char name[MAXPATHLEN];
312 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
313 if (ld_utrace != NULL) \
314 ld_utrace_log(e, h, mb, ms, r, n); \
318 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
319 int refcnt, const char *name)
321 struct utrace_rtld ut;
329 ut.mapbase = mapbase;
330 ut.mapsize = mapsize;
332 bzero(ut.name, sizeof(ut.name));
334 strlcpy(ut.name, name, sizeof(ut.name));
335 utrace(&ut, sizeof(ut));
339 * Main entry point for dynamic linking. The first argument is the
340 * stack pointer. The stack is expected to be laid out as described
341 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
342 * Specifically, the stack pointer points to a word containing
343 * ARGC. Following that in the stack is a null-terminated sequence
344 * of pointers to argument strings. Then comes a null-terminated
345 * sequence of pointers to environment strings. Finally, there is a
346 * sequence of "auxiliary vector" entries.
348 * The second argument points to a place to store the dynamic linker's
349 * exit procedure pointer and the third to a place to store the main
352 * The return value is the main program's entry point.
355 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
357 Elf_Auxinfo *aux_info[AT_COUNT];
365 Objlist_Entry *entry;
368 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld
369 Obj_Entry **preload_tail;
371 from global to here. It will break the DWARF2 unwind scheme.
372 The system compilers were unaffected, but not gcc 4.6
376 * On entry, the dynamic linker itself has not been relocated yet.
377 * Be very careful not to reference any global data until after
378 * init_rtld has returned. It is OK to reference file-scope statics
379 * and string constants, and to call static and global functions.
382 /* Find the auxiliary vector on the stack. */
385 sp += argc + 1; /* Skip over arguments and NULL terminator */
389 * If we aren't already resident we have to dig out some more info.
390 * Note that auxinfo does not exist when we are resident.
392 * I'm not sure about the ld_resident check. It seems to read zero
393 * prior to relocation, which is what we want. When running from a
394 * resident copy everything will be relocated so we are definitely
397 if (ld_resident == 0) {
398 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
400 aux = (Elf_Auxinfo *) sp;
402 /* Digest the auxiliary vector. */
403 for (i = 0; i < AT_COUNT; i++)
405 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
406 if (auxp->a_type < AT_COUNT)
407 aux_info[auxp->a_type] = auxp;
410 /* Initialize and relocate ourselves. */
411 assert(aux_info[AT_BASE] != NULL);
412 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
415 ld_index = 0; /* don't use old env cache in case we are resident */
416 __progname = obj_rtld.path;
417 argv0 = argv[0] != NULL ? argv[0] : "(null)";
422 trust = !issetugid();
424 ld_bind_now = _getenv_ld("LD_BIND_NOW");
426 * If the process is tainted, then we un-set the dangerous environment
427 * variables. The process will be marked as tainted until setuid(2)
428 * is called. If any child process calls setuid(2) we do not want any
429 * future processes to honor the potentially un-safe variables.
432 if ( unsetenv("LD_DEBUG")
433 || unsetenv("LD_PRELOAD")
434 || unsetenv("LD_LIBRARY_PATH")
435 || unsetenv("LD_ELF_HINTS_PATH")
436 || unsetenv("LD_LIBMAP")
437 || unsetenv("LD_LIBMAP_DISABLE")
438 || unsetenv("LD_LOADFLTR")
440 _rtld_error("environment corrupt; aborting");
444 ld_debug = _getenv_ld("LD_DEBUG");
445 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL;
446 libmap_override = (char *)_getenv_ld("LD_LIBMAP");
447 ld_library_path = _getenv_ld("LD_LIBRARY_PATH");
448 ld_preload = (char *)_getenv_ld("LD_PRELOAD");
449 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH");
450 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL;
451 dangerous_ld_env = (ld_library_path != NULL)
452 || (ld_preload != NULL)
453 || (ld_elf_hints_path != NULL)
455 || (libmap_override != NULL)
458 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS");
459 ld_utrace = _getenv_ld("LD_UTRACE");
461 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
462 ld_elf_hints_path = _PATH_ELF_HINTS;
464 if (ld_debug != NULL && *ld_debug != '\0')
466 dbg("%s is initialized, base address = %p", __progname,
467 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
468 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
469 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
471 dbg("initializing thread locks");
475 * If we are resident we can skip work that we have already done.
476 * Note that the stack is reset and there is no Elf_Auxinfo
477 * when running from a resident image, and the static globals setup
478 * between here and resident_skip will have already been setup.
484 * Load the main program, or process its program header if it is
487 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
488 int fd = aux_info[AT_EXECFD]->a_un.a_val;
489 dbg("loading main program");
490 obj_main = map_object(fd, argv0, NULL);
492 if (obj_main == NULL)
494 max_stack_flags = obj->stack_flags;
495 } else { /* Main program already loaded. */
496 const Elf_Phdr *phdr;
500 dbg("processing main program's program header");
501 assert(aux_info[AT_PHDR] != NULL);
502 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
503 assert(aux_info[AT_PHNUM] != NULL);
504 phnum = aux_info[AT_PHNUM]->a_un.a_val;
505 assert(aux_info[AT_PHENT] != NULL);
506 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
507 assert(aux_info[AT_ENTRY] != NULL);
508 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
509 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
513 char buf[MAXPATHLEN];
514 if (aux_info[AT_EXECPATH] != NULL) {
517 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
518 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
519 if (kexecpath[0] == '/')
520 obj_main->path = kexecpath;
521 else if (getcwd(buf, sizeof(buf)) == NULL ||
522 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
523 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
524 obj_main->path = xstrdup(argv0);
526 obj_main->path = xstrdup(buf);
528 char resolved[MAXPATHLEN];
529 dbg("No AT_EXECPATH");
530 if (argv0[0] == '/') {
531 if (realpath(argv0, resolved) != NULL)
532 obj_main->path = xstrdup(resolved);
534 obj_main->path = xstrdup(argv0);
536 if (getcwd(buf, sizeof(buf)) != NULL
537 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf)
538 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf)
539 && access(buf, R_OK) == 0
540 && realpath(buf, resolved) != NULL)
541 obj_main->path = xstrdup(resolved);
543 obj_main->path = xstrdup(argv0);
546 dbg("obj_main path %s", obj_main->path);
547 obj_main->mainprog = true;
549 if (aux_info[AT_STACKPROT] != NULL &&
550 aux_info[AT_STACKPROT]->a_un.a_val != 0)
551 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
554 * Get the actual dynamic linker pathname from the executable if
555 * possible. (It should always be possible.) That ensures that
556 * gdb will find the right dynamic linker even if a non-standard
559 if (obj_main->interp != NULL &&
560 strcmp(obj_main->interp, obj_rtld.path) != 0) {
562 obj_rtld.path = xstrdup(obj_main->interp);
563 __progname = obj_rtld.path;
566 digest_dynamic(obj_main, 0);
567 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
568 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
569 obj_main->dynsymcount);
571 linkmap_add(obj_main);
572 linkmap_add(&obj_rtld);
574 /* Link the main program into the list of objects. */
575 *obj_tail = obj_main;
576 obj_tail = &obj_main->next;
580 /* Initialize a fake symbol for resolving undefined weak references. */
581 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
582 sym_zero.st_shndx = SHN_UNDEF;
583 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
586 libmap_disable = (bool)lm_init(libmap_override);
588 dbg("loading LD_PRELOAD libraries");
589 if (load_preload_objects() == -1)
591 preload_tail = obj_tail;
593 dbg("loading needed objects");
594 if (load_needed_objects(obj_main, 0) == -1)
597 /* Make a list of all objects loaded at startup. */
598 for (obj = obj_list; obj != NULL; obj = obj->next) {
599 objlist_push_tail(&list_main, obj);
603 dbg("checking for required versions");
604 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
609 if (ld_tracing) { /* We're done */
610 trace_loaded_objects(obj_main);
614 if (ld_resident) /* XXX clean this up! */
617 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) {
618 dump_relocations(obj_main);
622 /* setup TLS for main thread */
623 dbg("initializing initial thread local storage");
624 STAILQ_FOREACH(entry, &list_main, link) {
626 * Allocate all the initial objects out of the static TLS
627 * block even if they didn't ask for it.
629 allocate_tls_offset(entry->obj);
632 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
635 * Do not try to allocate the TLS here, let libc do it itself.
636 * (crt1 for the program will call _init_tls())
639 if (relocate_objects(obj_main,
640 ld_bind_now != NULL && *ld_bind_now != '\0',
641 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
644 dbg("doing copy relocations");
645 if (do_copy_relocations(obj_main) == -1)
650 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) {
651 if (exec_sys_unregister(-1) < 0) {
652 dbg("exec_sys_unregister failed %d\n", errno);
655 dbg("exec_sys_unregister success\n");
659 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) {
660 dump_relocations(obj_main);
664 dbg("initializing key program variables");
665 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
666 set_program_var("environ", env);
667 set_program_var("__elf_aux_vector", aux);
669 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) {
670 extern void resident_start(void);
672 if (exec_sys_register(resident_start) < 0) {
673 dbg("exec_sys_register failed %d\n", errno);
676 dbg("exec_sys_register success\n");
680 /* Make a list of init functions to call. */
681 objlist_init(&initlist);
682 initlist_add_objects(obj_list, preload_tail, &initlist);
684 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
686 map_stacks_exec(NULL);
688 dbg("resolving ifuncs");
689 if (resolve_objects_ifunc(obj_main,
690 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
695 * Do NOT call the initlist here, give libc a chance to set up
696 * the initial TLS segment. crt1 will then call _rtld_call_init().
699 dbg("transferring control to program entry point = %p", obj_main->entry);
701 /* Return the exit procedure and the program entry point. */
702 *exit_proc = rtld_exit;
704 return (func_ptr_type) obj_main->entry;
708 * Call the initialization list for dynamically loaded libraries.
709 * (called from crt1.c).
712 _rtld_call_init(void)
714 RtldLockState lockstate;
717 if (!obj_main->note_present && obj_main->valid_hash_gnu) {
719 * The use of a linker script with a PHDRS directive that does not include
720 * PT_NOTE will block the crt_no_init note. In this case we'll look for the
721 * recently added GNU hash dynamic tag which gets built by default. It is
722 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and
723 * a gnu hash tag. If gnu hash found, consider binary to use new crt code.
725 obj_main->crt_no_init = true;
726 dbg("Setting crt_no_init without presence of PT_NOTE header");
729 wlock_acquire(rtld_bind_lock, &lockstate);
730 if (obj_main->crt_no_init) {
731 preinitialize_main_object();
735 * Make sure we don't call the main program's init and fini functions
736 * for binaries linked with old crt1 which calls _init itself.
738 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
739 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL;
741 objlist_call_init(&initlist, &lockstate);
742 objlist_clear(&initlist);
743 dbg("loading filtees");
744 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
745 if (ld_loadfltr || obj->z_loadfltr)
746 load_filtees(obj, 0, &lockstate);
748 lock_release(rtld_bind_lock, &lockstate);
752 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
757 ptr = (void *)make_function_pointer(def, obj);
758 target = ((Elf_Addr (*)(void))ptr)();
759 return ((void *)target);
763 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack)
767 const Obj_Entry *defobj;
770 RtldLockState lockstate;
772 rlock_acquire(rtld_bind_lock, &lockstate);
773 if (sigsetjmp(lockstate.env, 0) != 0)
774 lock_upgrade(rtld_bind_lock, &lockstate);
776 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
778 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
780 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
781 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
785 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
786 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
788 target = (Elf_Addr)(defobj->relocbase + def->st_value);
790 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
791 defobj->strtab + def->st_name, basename(obj->path),
792 (void *)target, basename(defobj->path));
795 * If we have a function call tracing hook, and the
796 * hook would like to keep tracing this one function,
797 * prevent the relocation so we will wind up here
798 * the next time again.
800 * We don't want to functrace calls from the functracer
801 * to avoid recursive loops.
803 if (rtld_functrace != NULL && obj != rtld_functrace_obj) {
804 if (rtld_functrace(obj->path,
806 defobj->strtab + def->st_name,
808 lock_release(rtld_bind_lock, &lockstate);
814 * Write the new contents for the jmpslot. Note that depending on
815 * architecture, the value which we need to return back to the
816 * lazy binding trampoline may or may not be the target
817 * address. The value returned from reloc_jmpslot() is the value
818 * that the trampoline needs.
820 target = reloc_jmpslot(where, target, defobj, obj, rel);
821 lock_release(rtld_bind_lock, &lockstate);
826 * Error reporting function. Use it like printf. If formats the message
827 * into a buffer, and sets things up so that the next call to dlerror()
828 * will return the message.
831 _rtld_error(const char *fmt, ...)
833 static char buf[512];
837 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
843 * Return a dynamically-allocated copy of the current error message, if any.
848 return error_message == NULL ? NULL : xstrdup(error_message);
852 * Restore the current error message from a copy which was previously saved
853 * by errmsg_save(). The copy is freed.
856 errmsg_restore(char *saved_msg)
858 if (saved_msg == NULL)
859 error_message = NULL;
861 _rtld_error("%s", saved_msg);
867 basename(const char *name)
869 const char *p = strrchr(name, '/');
870 return p != NULL ? p + 1 : name;
873 static struct utsname uts;
876 origin_subst_one(char *real, const char *kw, const char *subst,
879 char *p, *p1, *res, *resp;
880 int subst_len, kw_len, subst_count, old_len, new_len;
885 * First, count the number of the keyword occurences, to
886 * preallocate the final string.
888 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
895 * If the keyword is not found, just return.
897 if (subst_count == 0)
898 return (may_free ? real : xstrdup(real));
901 * There is indeed something to substitute. Calculate the
902 * length of the resulting string, and allocate it.
904 subst_len = strlen(subst);
905 old_len = strlen(real);
906 new_len = old_len + (subst_len - kw_len) * subst_count;
907 res = xmalloc(new_len + 1);
910 * Now, execute the substitution loop.
912 for (p = real, resp = res, *resp = '\0';;) {
915 /* Copy the prefix before keyword. */
916 memcpy(resp, p, p1 - p);
918 /* Keyword replacement. */
919 memcpy(resp, subst, subst_len);
927 /* Copy to the end of string and finish. */
935 origin_subst(char *real, const char *origin_path)
937 char *res1, *res2, *res3, *res4;
939 if (uts.sysname[0] == '\0') {
940 if (uname(&uts) != 0) {
941 _rtld_error("utsname failed: %d", errno);
945 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
946 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
947 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
948 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
955 const char *msg = dlerror();
959 rtld_fdputstr(STDERR_FILENO, msg);
960 rtld_fdputchar(STDERR_FILENO, '\n');
965 * Process a shared object's DYNAMIC section, and save the important
966 * information in its Obj_Entry structure.
969 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
970 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
973 Needed_Entry **needed_tail = &obj->needed;
974 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
975 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
976 const Elf_Hashelt *hashtab;
977 const Elf32_Word *hashval;
978 Elf32_Word bkt, nmaskwords;
981 int plttype = DT_REL;
987 obj->bind_now = false;
988 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
989 switch (dynp->d_tag) {
992 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
996 obj->relsize = dynp->d_un.d_val;
1000 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1004 obj->pltrel = (const Elf_Rel *)
1005 (obj->relocbase + dynp->d_un.d_ptr);
1009 obj->pltrelsize = dynp->d_un.d_val;
1013 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
1017 obj->relasize = dynp->d_un.d_val;
1021 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1025 plttype = dynp->d_un.d_val;
1026 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1030 obj->symtab = (const Elf_Sym *)
1031 (obj->relocbase + dynp->d_un.d_ptr);
1035 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1039 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
1043 obj->strsize = dynp->d_un.d_val;
1047 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
1052 obj->verneednum = dynp->d_un.d_val;
1056 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1061 obj->verdefnum = dynp->d_un.d_val;
1065 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1071 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1073 obj->nbuckets = hashtab[0];
1074 obj->nchains = hashtab[1];
1075 obj->buckets = hashtab + 2;
1076 obj->chains = obj->buckets + obj->nbuckets;
1077 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1078 obj->buckets != NULL;
1084 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1086 obj->nbuckets_gnu = hashtab[0];
1087 obj->symndx_gnu = hashtab[1];
1088 nmaskwords = hashtab[2];
1089 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1090 /* Number of bitmask words is required to be power of 2 */
1091 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
1092 obj->maskwords_bm_gnu = nmaskwords - 1;
1093 obj->shift2_gnu = hashtab[3];
1094 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1095 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1096 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1098 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
1099 obj->buckets_gnu != NULL;
1105 Needed_Entry *nep = NEW(Needed_Entry);
1106 nep->name = dynp->d_un.d_val;
1111 needed_tail = &nep->next;
1117 Needed_Entry *nep = NEW(Needed_Entry);
1118 nep->name = dynp->d_un.d_val;
1122 *needed_filtees_tail = nep;
1123 needed_filtees_tail = &nep->next;
1129 Needed_Entry *nep = NEW(Needed_Entry);
1130 nep->name = dynp->d_un.d_val;
1134 *needed_aux_filtees_tail = nep;
1135 needed_aux_filtees_tail = &nep->next;
1140 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1144 obj->textrel = true;
1148 obj->symbolic = true;
1153 * We have to wait until later to process this, because we
1154 * might not have gotten the address of the string table yet.
1164 *dyn_runpath = dynp;
1168 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1172 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1175 case DT_PREINIT_ARRAY:
1176 obj->preinit_array = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1180 obj->init_array = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1184 obj->fini_array = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1187 case DT_PREINIT_ARRAYSZ:
1188 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1191 case DT_INIT_ARRAYSZ:
1192 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1195 case DT_FINI_ARRAYSZ:
1196 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1200 /* XXX - not implemented yet */
1202 dbg("Filling in DT_DEBUG entry");
1203 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1207 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1208 obj->z_origin = true;
1209 if (dynp->d_un.d_val & DF_SYMBOLIC)
1210 obj->symbolic = true;
1211 if (dynp->d_un.d_val & DF_TEXTREL)
1212 obj->textrel = true;
1213 if (dynp->d_un.d_val & DF_BIND_NOW)
1214 obj->bind_now = true;
1215 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1220 if (dynp->d_un.d_val & DF_1_NOOPEN)
1221 obj->z_noopen = true;
1222 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1223 obj->z_origin = true;
1224 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1226 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1227 obj->bind_now = true;
1228 if (dynp->d_un.d_val & DF_1_NODELETE)
1229 obj->z_nodelete = true;
1230 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1231 obj->z_loadfltr = true;
1232 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1233 obj->z_nodeflib = true;
1238 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1245 obj->traced = false;
1247 if (plttype == DT_RELA) {
1248 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1250 obj->pltrelasize = obj->pltrelsize;
1251 obj->pltrelsize = 0;
1254 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1255 if (obj->valid_hash_sysv)
1256 obj->dynsymcount = obj->nchains;
1257 else if (obj->valid_hash_gnu) {
1258 obj->dynsymcount = 0;
1259 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1260 if (obj->buckets_gnu[bkt] == 0)
1262 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1265 while ((*hashval++ & 1u) == 0);
1267 obj->dynsymcount += obj->symndx_gnu;
1272 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1273 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1276 if (obj->z_origin && obj->origin_path == NULL) {
1277 obj->origin_path = xmalloc(PATH_MAX);
1278 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1282 if (dyn_runpath != NULL) {
1283 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1285 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1287 else if (dyn_rpath != NULL) {
1288 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1290 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1293 if (dyn_soname != NULL)
1294 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1298 digest_dynamic(Obj_Entry *obj, int early)
1300 const Elf_Dyn *dyn_rpath;
1301 const Elf_Dyn *dyn_soname;
1302 const Elf_Dyn *dyn_runpath;
1304 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1305 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1309 * Process a shared object's program header. This is used only for the
1310 * main program, when the kernel has already loaded the main program
1311 * into memory before calling the dynamic linker. It creates and
1312 * returns an Obj_Entry structure.
1315 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1318 const Elf_Phdr *phlimit = phdr + phnum;
1320 Elf_Addr note_start, note_end;
1324 for (ph = phdr; ph < phlimit; ph++) {
1325 if (ph->p_type != PT_PHDR)
1329 obj->phsize = ph->p_memsz;
1330 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1334 obj->stack_flags = PF_X | PF_R | PF_W;
1336 for (ph = phdr; ph < phlimit; ph++) {
1337 switch (ph->p_type) {
1340 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1344 if (nsegs == 0) { /* First load segment */
1345 obj->vaddrbase = trunc_page(ph->p_vaddr);
1346 obj->mapbase = obj->vaddrbase + obj->relocbase;
1347 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1349 } else { /* Last load segment */
1350 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1357 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1362 obj->tlssize = ph->p_memsz;
1363 obj->tlsalign = ph->p_align;
1364 obj->tlsinitsize = ph->p_filesz;
1365 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1369 obj->stack_flags = ph->p_flags;
1373 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1374 obj->relro_size = round_page(ph->p_memsz);
1378 obj->note_present = true;
1379 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1380 note_end = note_start + ph->p_filesz;
1381 digest_notes(obj, note_start, note_end);
1386 _rtld_error("%s: too few PT_LOAD segments", path);
1395 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1397 const Elf_Note *note;
1398 const char *note_name;
1401 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1402 note = (const Elf_Note *)((const char *)(note + 1) +
1403 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1404 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1405 if (note->n_namesz != sizeof(NOTE_VENDOR) ||
1406 note->n_descsz != sizeof(int32_t))
1408 if (note->n_type != ABI_NOTETYPE && note->n_type != CRT_NOINIT_NOTETYPE)
1410 note_name = (const char *)(note + 1);
1411 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0)
1413 switch (note->n_type) {
1415 /* DragonFly osrel note */
1416 p = (uintptr_t)(note + 1);
1417 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1418 obj->osrel = *(const int32_t *)(p);
1419 dbg("note osrel %d", obj->osrel);
1421 case CRT_NOINIT_NOTETYPE:
1422 /* DragonFly 'crt does not call init' note */
1423 obj->crt_no_init = true;
1424 dbg("note crt_no_init");
1431 dlcheck(void *handle)
1435 for (obj = obj_list; obj != NULL; obj = obj->next)
1436 if (obj == (Obj_Entry *) handle)
1439 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1440 _rtld_error("Invalid shared object handle %p", handle);
1447 * If the given object is already in the donelist, return true. Otherwise
1448 * add the object to the list and return false.
1451 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1455 for (i = 0; i < dlp->num_used; i++)
1456 if (dlp->objs[i] == obj)
1459 * Our donelist allocation should always be sufficient. But if
1460 * our threads locking isn't working properly, more shared objects
1461 * could have been loaded since we allocated the list. That should
1462 * never happen, but we'll handle it properly just in case it does.
1464 if (dlp->num_used < dlp->num_alloc)
1465 dlp->objs[dlp->num_used++] = obj;
1470 * Hash function for symbol table lookup. Don't even think about changing
1471 * this. It is specified by the System V ABI.
1474 elf_hash(const char *name)
1476 const unsigned char *p = (const unsigned char *) name;
1477 unsigned long h = 0;
1480 while (*p != '\0') {
1481 h = (h << 4) + *p++;
1482 if ((g = h & 0xf0000000) != 0)
1490 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1491 * unsigned in case it's implemented with a wider type.
1493 static uint_fast32_t
1494 gnu_hash (const char *s)
1496 uint_fast32_t h = 5381;
1497 for (unsigned char c = *s; c != '\0'; c = *++s)
1499 return h & 0xffffffff;
1503 * Find the library with the given name, and return its full pathname.
1504 * The returned string is dynamically allocated. Generates an error
1505 * message and returns NULL if the library cannot be found.
1507 * If the second argument is non-NULL, then it refers to an already-
1508 * loaded shared object, whose library search path will be searched.
1510 * The search order is:
1511 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1512 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1514 * DT_RUNPATH in the referencing file
1515 * ldconfig hints (if -z nodefaultlib, filter out /usr/lib from list)
1516 * /usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1518 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1521 find_library(const char *xname, const Obj_Entry *refobj)
1525 bool nodeflib, objgiven;
1527 objgiven = refobj != NULL;
1528 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1529 if (xname[0] != '/' && !trust) {
1530 _rtld_error("Absolute pathname required for shared object \"%s\"",
1534 if (objgiven && refobj->z_origin) {
1535 return (origin_subst(__DECONST(char *, xname),
1536 refobj->origin_path));
1538 return (xstrdup(xname));
1542 if (libmap_disable || !objgiven ||
1543 (name = lm_find(refobj->path, xname)) == NULL)
1544 name = (char *)xname;
1546 dbg(" Searching for \"%s\"", name);
1548 nodeflib = objgiven ? refobj->z_nodeflib : false;
1550 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1551 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1552 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1553 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1555 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1556 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1557 (objgiven && !nodeflib &&
1558 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1561 if (objgiven && refobj->path != NULL) {
1562 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1563 name, basename(refobj->path));
1565 _rtld_error("Shared object \"%s\" not found", name);
1571 * Given a symbol number in a referencing object, find the corresponding
1572 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1573 * no definition was found. Returns a pointer to the Obj_Entry of the
1574 * defining object via the reference parameter DEFOBJ_OUT.
1577 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1578 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1579 RtldLockState *lockstate)
1583 const Obj_Entry *defobj;
1589 * If we have already found this symbol, get the information from
1592 if (symnum >= refobj->dynsymcount)
1593 return NULL; /* Bad object */
1594 if (cache != NULL && cache[symnum].sym != NULL) {
1595 *defobj_out = cache[symnum].obj;
1596 return cache[symnum].sym;
1599 ref = refobj->symtab + symnum;
1600 name = refobj->strtab + ref->st_name;
1605 * We don't have to do a full scale lookup if the symbol is local.
1606 * We know it will bind to the instance in this load module; to
1607 * which we already have a pointer (ie ref). By not doing a lookup,
1608 * we not only improve performance, but it also avoids unresolvable
1609 * symbols when local symbols are not in the hash table.
1611 * This might occur for TLS module relocations, which simply use
1614 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1615 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1616 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1619 symlook_init(&req, name);
1621 req.ventry = fetch_ventry(refobj, symnum);
1622 req.lockstate = lockstate;
1623 res = symlook_default(&req, refobj);
1626 defobj = req.defobj_out;
1634 * If we found no definition and the reference is weak, treat the
1635 * symbol as having the value zero.
1637 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1643 *defobj_out = defobj;
1644 /* Record the information in the cache to avoid subsequent lookups. */
1645 if (cache != NULL) {
1646 cache[symnum].sym = def;
1647 cache[symnum].obj = defobj;
1650 if (refobj != &obj_rtld)
1651 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1657 * Return the search path from the ldconfig hints file, reading it if
1658 * necessary. Returns NULL if there are problems with the hints file,
1659 * or if the search path there is empty.
1660 * If DF_1_NODEFLIB flag set, omit STANDARD_LIBRARY_PATH directories
1663 gethints(bool nostdlib)
1665 static char *hints, *filtered_path;
1666 struct elfhints_hdr hdr;
1667 struct fill_search_info_args sargs, hargs;
1668 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1669 struct dl_serpath *SLPpath, *hintpath;
1671 unsigned int SLPndx, hintndx, fndx, fcount;
1676 if (hints == NULL) {
1677 /* Keep from trying again in case the hints file is bad. */
1680 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1682 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1683 hdr.magic != ELFHINTS_MAGIC || hdr.version != 1) {
1687 p = xmalloc(hdr.dirlistlen + 1);
1688 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1689 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1699 return (hints[0] != '\0' ? hints : NULL);
1701 if (filtered_path != NULL)
1704 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1706 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1709 sargs.request = RTLD_DI_SERINFOSIZE;
1710 sargs.serinfo = &smeta;
1711 hargs.request = RTLD_DI_SERINFOSIZE;
1712 hargs.serinfo = &hmeta;
1714 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1715 path_enumerate(p, fill_search_info, &hargs);
1717 SLPinfo = malloc(smeta.dls_size);
1718 hintinfo = malloc(hmeta.dls_size);
1720 sargs.request = RTLD_DI_SERINFO;
1721 sargs.serinfo = SLPinfo;
1722 sargs.serpath = &SLPinfo->dls_serpath[0];
1723 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1725 hargs.request = RTLD_DI_SERINFO;
1726 hargs.serinfo = hintinfo;
1727 hargs.serpath = &hintinfo->dls_serpath[0];
1728 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1730 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1731 path_enumerate(p, fill_search_info, &hargs);
1735 filtered_path = xmalloc(hdr.dirlistlen + 1);
1736 hintpath = &hintinfo->dls_serpath[0];
1737 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1739 SLPpath = &SLPinfo->dls_serpath[0];
1740 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1741 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1749 filtered_path[fndx] = ':';
1753 flen = strlen(hintpath->dls_name);
1754 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1757 filtered_path[fndx] = '\0';
1763 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1767 init_dag(Obj_Entry *root)
1769 const Needed_Entry *needed;
1770 const Objlist_Entry *elm;
1773 if (root->dag_inited)
1775 donelist_init(&donelist);
1777 /* Root object belongs to own DAG. */
1778 objlist_push_tail(&root->dldags, root);
1779 objlist_push_tail(&root->dagmembers, root);
1780 donelist_check(&donelist, root);
1783 * Add dependencies of root object to DAG in breadth order
1784 * by exploiting the fact that each new object get added
1785 * to the tail of the dagmembers list.
1787 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1788 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1789 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1791 objlist_push_tail(&needed->obj->dldags, root);
1792 objlist_push_tail(&root->dagmembers, needed->obj);
1795 root->dag_inited = true;
1799 process_nodelete(Obj_Entry *root)
1801 const Objlist_Entry *elm;
1804 * Walk over object DAG and process every dependent object that
1805 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1806 * which then should have its reference upped separately.
1808 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1809 if (elm->obj != NULL && elm->obj->z_nodelete &&
1810 !elm->obj->ref_nodel) {
1811 dbg("obj %s nodelete", elm->obj->path);
1814 elm->obj->ref_nodel = true;
1820 * Initialize the dynamic linker. The argument is the address at which
1821 * the dynamic linker has been mapped into memory. The primary task of
1822 * this function is to relocate the dynamic linker.
1825 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1827 Obj_Entry objtmp; /* Temporary rtld object */
1828 const Elf_Dyn *dyn_rpath;
1829 const Elf_Dyn *dyn_soname;
1830 const Elf_Dyn *dyn_runpath;
1833 * Conjure up an Obj_Entry structure for the dynamic linker.
1835 * The "path" member can't be initialized yet because string constants
1836 * cannot yet be accessed. Below we will set it correctly.
1838 memset(&objtmp, 0, sizeof(objtmp));
1841 objtmp.mapbase = mapbase;
1843 objtmp.relocbase = mapbase;
1845 if (RTLD_IS_DYNAMIC()) {
1846 objtmp.dynamic = rtld_dynamic(&objtmp);
1847 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1848 assert(objtmp.needed == NULL);
1849 assert(!objtmp.textrel);
1852 * Temporarily put the dynamic linker entry into the object list, so
1853 * that symbols can be found.
1856 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1859 /* Initialize the object list. */
1860 obj_tail = &obj_list;
1862 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1863 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1865 #ifdef ENABLE_OSRELDATE
1866 if (aux_info[AT_OSRELDATE] != NULL)
1867 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1870 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1872 /* Replace the path with a dynamically allocated copy. */
1873 obj_rtld.path = xstrdup(PATH_RTLD);
1875 r_debug.r_brk = r_debug_state;
1876 r_debug.r_state = RT_CONSISTENT;
1880 * Add the init functions from a needed object list (and its recursive
1881 * needed objects) to "list". This is not used directly; it is a helper
1882 * function for initlist_add_objects(). The write lock must be held
1883 * when this function is called.
1886 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1888 /* Recursively process the successor needed objects. */
1889 if (needed->next != NULL)
1890 initlist_add_neededs(needed->next, list);
1892 /* Process the current needed object. */
1893 if (needed->obj != NULL)
1894 initlist_add_objects(needed->obj, &needed->obj->next, list);
1898 * Scan all of the DAGs rooted in the range of objects from "obj" to
1899 * "tail" and add their init functions to "list". This recurses over
1900 * the DAGs and ensure the proper init ordering such that each object's
1901 * needed libraries are initialized before the object itself. At the
1902 * same time, this function adds the objects to the global finalization
1903 * list "list_fini" in the opposite order. The write lock must be
1904 * held when this function is called.
1907 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1910 if (obj->init_scanned || obj->init_done)
1912 obj->init_scanned = true;
1914 /* Recursively process the successor objects. */
1915 if (&obj->next != tail)
1916 initlist_add_objects(obj->next, tail, list);
1918 /* Recursively process the needed objects. */
1919 if (obj->needed != NULL)
1920 initlist_add_neededs(obj->needed, list);
1921 if (obj->needed_filtees != NULL)
1922 initlist_add_neededs(obj->needed_filtees, list);
1923 if (obj->needed_aux_filtees != NULL)
1924 initlist_add_neededs(obj->needed_aux_filtees, list);
1926 /* Add the object to the init list. */
1927 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1928 obj->init_array != (Elf_Addr)NULL)
1929 objlist_push_tail(list, obj);
1931 /* Add the object to the global fini list in the reverse order. */
1932 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1933 && !obj->on_fini_list) {
1934 objlist_push_head(&list_fini, obj);
1935 obj->on_fini_list = true;
1940 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1944 is_exported(const Elf_Sym *def)
1947 const func_ptr_type *p;
1949 value = (Elf_Addr)(obj_rtld.relocbase + def->st_value);
1950 for (p = exports; *p != NULL; p++)
1951 if (FPTR_TARGET(*p) == value)
1957 free_needed_filtees(Needed_Entry *n)
1959 Needed_Entry *needed, *needed1;
1961 for (needed = n; needed != NULL; needed = needed->next) {
1962 if (needed->obj != NULL) {
1963 dlclose(needed->obj);
1967 for (needed = n; needed != NULL; needed = needed1) {
1968 needed1 = needed->next;
1974 unload_filtees(Obj_Entry *obj)
1977 free_needed_filtees(obj->needed_filtees);
1978 obj->needed_filtees = NULL;
1979 free_needed_filtees(obj->needed_aux_filtees);
1980 obj->needed_aux_filtees = NULL;
1981 obj->filtees_loaded = false;
1985 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
1986 RtldLockState *lockstate)
1989 for (; needed != NULL; needed = needed->next) {
1990 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1991 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1992 RTLD_LOCAL, lockstate);
1997 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2000 lock_restart_for_upgrade(lockstate);
2001 if (!obj->filtees_loaded) {
2002 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2003 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2004 obj->filtees_loaded = true;
2009 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2013 for (; needed != NULL; needed = needed->next) {
2014 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2015 flags & ~RTLD_LO_NOLOAD);
2016 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2023 * Given a shared object, traverse its list of needed objects, and load
2024 * each of them. Returns 0 on success. Generates an error message and
2025 * returns -1 on failure.
2028 load_needed_objects(Obj_Entry *first, int flags)
2032 for (obj = first; obj != NULL; obj = obj->next) {
2033 if (process_needed(obj, obj->needed, flags) == -1)
2040 load_preload_objects(void)
2042 char *p = ld_preload;
2043 static const char delim[] = " \t:;";
2048 p += strspn(p, delim);
2049 while (*p != '\0') {
2050 size_t len = strcspn(p, delim);
2058 obj = load_object(p, -1, NULL, 0);
2060 return -1; /* XXX - cleanup */
2063 p += strspn(p, delim);
2065 /* Check for the magic tracing function */
2066 symlook_init(&req, RTLD_FUNCTRACE);
2067 res = symlook_obj(&req, obj);
2069 rtld_functrace = (void *)(req.defobj_out->relocbase +
2070 req.sym_out->st_value);
2071 rtld_functrace_obj = req.defobj_out;
2074 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2079 printable_path(const char *path)
2082 return (path == NULL ? "<unknown>" : path);
2086 * Load a shared object into memory, if it is not already loaded. The
2087 * object may be specified by name or by user-supplied file descriptor
2088 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2091 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2095 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2103 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2104 if (object_match_name(obj, name))
2108 path = find_library(name, refobj);
2115 * If we didn't find a match by pathname, or the name is not
2116 * supplied, open the file and check again by device and inode.
2117 * This avoids false mismatches caused by multiple links or ".."
2120 * To avoid a race, we open the file and use fstat() rather than
2125 if ((fd = open(path, O_RDONLY)) == -1) {
2126 _rtld_error("Cannot open \"%s\"", path);
2133 _rtld_error("Cannot dup fd");
2138 if (fstat(fd, &sb) == -1) {
2139 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2144 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2145 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2147 if (obj != NULL && name != NULL) {
2148 object_add_name(obj, name);
2153 if (flags & RTLD_LO_NOLOAD) {
2159 /* First use of this object, so we must map it in */
2160 obj = do_load_object(fd, name, path, &sb, flags);
2169 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2176 * but first, make sure that environment variables haven't been
2177 * used to circumvent the noexec flag on a filesystem.
2179 if (dangerous_ld_env) {
2180 if (fstatfs(fd, &fs) != 0) {
2181 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2184 if (fs.f_flags & MNT_NOEXEC) {
2185 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2189 dbg("loading \"%s\"", printable_path(path));
2190 obj = map_object(fd, printable_path(path), sbp);
2195 * If DT_SONAME is present in the object, digest_dynamic2 already
2196 * added it to the object names.
2199 object_add_name(obj, name);
2201 digest_dynamic(obj, 0);
2202 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2203 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2204 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2206 dbg("refusing to load non-loadable \"%s\"", obj->path);
2207 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2208 munmap(obj->mapbase, obj->mapsize);
2214 obj_tail = &obj->next;
2217 linkmap_add(obj); /* for GDB & dlinfo() */
2218 max_stack_flags |= obj->stack_flags;
2220 dbg(" %p .. %p: %s", obj->mapbase,
2221 obj->mapbase + obj->mapsize - 1, obj->path);
2223 dbg(" WARNING: %s has impure text", obj->path);
2224 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2231 obj_from_addr(const void *addr)
2235 for (obj = obj_list; obj != NULL; obj = obj->next) {
2236 if (addr < (void *) obj->mapbase)
2238 if (addr < (void *) (obj->mapbase + obj->mapsize))
2245 * Call the finalization functions for each of the objects in "list"
2246 * belonging to the DAG of "root" and referenced once. If NULL "root"
2247 * is specified, every finalization function will be called regardless
2248 * of the reference count and the list elements won't be freed. All of
2249 * the objects are expected to have non-NULL fini functions.
2252 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2256 Elf_Addr *fini_addr;
2259 assert(root == NULL || root->refcount == 1);
2262 * Preserve the current error message since a fini function might
2263 * call into the dynamic linker and overwrite it.
2265 saved_msg = errmsg_save();
2267 STAILQ_FOREACH(elm, list, link) {
2268 if (root != NULL && (elm->obj->refcount != 1 ||
2269 objlist_find(&root->dagmembers, elm->obj) == NULL))
2272 /* Remove object from fini list to prevent recursive invocation. */
2273 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2275 * XXX: If a dlopen() call references an object while the
2276 * fini function is in progress, we might end up trying to
2277 * unload the referenced object in dlclose() or the object
2278 * won't be unloaded although its fini function has been
2281 lock_release(rtld_bind_lock, lockstate);
2284 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. When this
2285 * happens, DT_FINI_ARRAY is processed first, and it is also processed
2286 * backwards. It is possible to encounter DT_FINI_ARRAY elements with
2287 * values of 0 or 1, but they need to be ignored.
2289 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2290 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2291 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) {
2292 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2293 dbg("calling fini array function for %s at %p",
2294 elm->obj->path, (void *)fini_addr[index]);
2295 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2296 (void *)fini_addr[index], 0, 0, elm->obj->path);
2297 call_initfini_pointer(elm->obj, fini_addr[index]);
2301 if (elm->obj->fini != (Elf_Addr)NULL) {
2302 dbg("calling fini function for %s at %p", elm->obj->path,
2303 (void *)elm->obj->fini);
2304 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2305 0, 0, elm->obj->path);
2306 call_initfini_pointer(elm->obj, elm->obj->fini);
2308 wlock_acquire(rtld_bind_lock, lockstate);
2309 /* No need to free anything if process is going down. */
2313 * We must restart the list traversal after every fini call
2314 * because a dlclose() call from the fini function or from
2315 * another thread might have modified the reference counts.
2319 } while (elm != NULL);
2320 errmsg_restore(saved_msg);
2324 * If the main program is defined with a .preinit_array section, call
2325 * each function in order. This must occur before the initialization
2326 * of any shared object or the main program.
2329 preinitialize_main_object (void)
2331 Elf_Addr *preinit_addr;
2334 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2335 if (preinit_addr == NULL)
2338 for (index = 0; index < obj_main->preinit_array_num; index++) {
2339 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2340 dbg("calling preinit function for %s at %p", obj_main->path,
2341 (void *)preinit_addr[index]);
2342 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2343 0, 0, obj_main->path);
2344 call_init_pointer(obj_main, preinit_addr[index]);
2350 * Call the initialization functions for each of the objects in
2351 * "list". All of the objects are expected to have non-NULL init
2355 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2360 Elf_Addr *init_addr;
2364 * Clean init_scanned flag so that objects can be rechecked and
2365 * possibly initialized earlier if any of vectors called below
2366 * cause the change by using dlopen.
2368 for (obj = obj_list; obj != NULL; obj = obj->next)
2369 obj->init_scanned = false;
2372 * Preserve the current error message since an init function might
2373 * call into the dynamic linker and overwrite it.
2375 saved_msg = errmsg_save();
2376 STAILQ_FOREACH(elm, list, link) {
2377 if (elm->obj->init_done) /* Initialized early. */
2381 * Race: other thread might try to use this object before current
2382 * one completes the initilization. Not much can be done here
2383 * without better locking.
2385 elm->obj->init_done = true;
2386 lock_release(rtld_bind_lock, lockstate);
2389 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. When
2390 * this happens, DT_INIT is processed first. It is possible to
2391 * encounter DT_INIT_ARRAY elements with values of 0 or 1, but they
2392 * need to be ignored.
2394 if (elm->obj->init != (Elf_Addr)NULL) {
2395 dbg("calling init function for %s at %p", elm->obj->path,
2396 (void *)elm->obj->init);
2397 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2398 0, 0, elm->obj->path);
2399 call_initfini_pointer(elm->obj, elm->obj->init);
2401 init_addr = (Elf_Addr *)elm->obj->init_array;
2402 if (init_addr != NULL) {
2403 for (index = 0; index < elm->obj->init_array_num; index++) {
2404 if (init_addr[index] != 0 && init_addr[index] != 1) {
2405 dbg("calling init array function for %s at %p", elm->obj->path,
2406 (void *)init_addr[index]);
2407 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2408 (void *)init_addr[index], 0, 0, elm->obj->path);
2409 call_init_pointer(elm->obj, init_addr[index]);
2413 wlock_acquire(rtld_bind_lock, lockstate);
2415 errmsg_restore(saved_msg);
2419 objlist_clear(Objlist *list)
2423 while (!STAILQ_EMPTY(list)) {
2424 elm = STAILQ_FIRST(list);
2425 STAILQ_REMOVE_HEAD(list, link);
2430 static Objlist_Entry *
2431 objlist_find(Objlist *list, const Obj_Entry *obj)
2435 STAILQ_FOREACH(elm, list, link)
2436 if (elm->obj == obj)
2442 objlist_init(Objlist *list)
2448 objlist_push_head(Objlist *list, Obj_Entry *obj)
2452 elm = NEW(Objlist_Entry);
2454 STAILQ_INSERT_HEAD(list, elm, link);
2458 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2462 elm = NEW(Objlist_Entry);
2464 STAILQ_INSERT_TAIL(list, elm, link);
2468 objlist_remove(Objlist *list, Obj_Entry *obj)
2472 if ((elm = objlist_find(list, obj)) != NULL) {
2473 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2479 * Relocate dag rooted in the specified object.
2480 * Returns 0 on success, or -1 on failure.
2484 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2485 int flags, RtldLockState *lockstate)
2491 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2492 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2501 * Relocate single object.
2502 * Returns 0 on success, or -1 on failure.
2506 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2507 int flags, RtldLockState *lockstate)
2511 obj->relocated = true;
2513 dbg("relocating \"%s\"", obj->path);
2515 if (obj->symtab == NULL || obj->strtab == NULL ||
2516 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2517 _rtld_error("%s: Shared object has no run-time symbol table",
2523 /* There are relocations to the write-protected text segment. */
2524 if (mprotect(obj->mapbase, obj->textsize,
2525 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2526 _rtld_error("%s: Cannot write-enable text segment: %s",
2527 obj->path, rtld_strerror(errno));
2532 /* Process the non-PLT relocations. */
2533 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2537 * Reprotect the text segment. Make sure it is included in the
2538 * core dump since we modified it. This unfortunately causes the
2539 * entire text segment to core-out but we don't have much of a
2540 * choice. We could try to only reenable core dumps on pages
2541 * in which relocations occured but that is likely most of the text
2542 * pages anyway, and even that would not work because the rest of
2543 * the text pages would wind up as a read-only OBJT_DEFAULT object
2544 * (created due to our modifications) backed by the original OBJT_VNODE
2545 * object, and the ELF coredump code is currently only able to dump
2546 * vnode records for pure vnode-backed mappings, not vnode backings
2547 * to memory objects.
2550 madvise(obj->mapbase, obj->textsize, MADV_CORE);
2551 if (mprotect(obj->mapbase, obj->textsize,
2552 PROT_READ|PROT_EXEC) == -1) {
2553 _rtld_error("%s: Cannot write-protect text segment: %s",
2554 obj->path, rtld_strerror(errno));
2560 /* Set the special PLT or GOT entries. */
2563 /* Process the PLT relocations. */
2564 if (reloc_plt(obj) == -1)
2566 /* Relocate the jump slots if we are doing immediate binding. */
2567 if (obj->bind_now || bind_now)
2568 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2572 * Set up the magic number and version in the Obj_Entry. These
2573 * were checked in the crt1.o from the original ElfKit, so we
2574 * set them for backward compatibility.
2576 obj->magic = RTLD_MAGIC;
2577 obj->version = RTLD_VERSION;
2580 * Set relocated data to read-only status if protection specified
2583 if (obj->relro_size) {
2584 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
2585 _rtld_error("%s: Cannot enforce relro relocation: %s",
2586 obj->path, rtld_strerror(errno));
2594 * Relocate newly-loaded shared objects. The argument is a pointer to
2595 * the Obj_Entry for the first such object. All objects from the first
2596 * to the end of the list of objects are relocated. Returns 0 on success,
2600 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2601 int flags, RtldLockState *lockstate)
2606 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2607 error = relocate_object(obj, bind_now, rtldobj, flags,
2616 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2617 * referencing STT_GNU_IFUNC symbols is postponed till the other
2618 * relocations are done. The indirect functions specified as
2619 * ifunc are allowed to call other symbols, so we need to have
2620 * objects relocated before asking for resolution from indirects.
2622 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2623 * instead of the usual lazy handling of PLT slots. It is
2624 * consistent with how GNU does it.
2627 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2628 RtldLockState *lockstate)
2630 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2632 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2633 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2639 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2640 RtldLockState *lockstate)
2644 for (obj = first; obj != NULL; obj = obj->next) {
2645 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2652 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2653 RtldLockState *lockstate)
2657 STAILQ_FOREACH(elm, list, link) {
2658 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2666 * Cleanup procedure. It will be called (by the atexit mechanism) just
2667 * before the process exits.
2672 RtldLockState lockstate;
2674 wlock_acquire(rtld_bind_lock, &lockstate);
2676 objlist_call_fini(&list_fini, NULL, &lockstate);
2677 /* No need to remove the items from the list, since we are exiting. */
2678 if (!libmap_disable)
2680 lock_release(rtld_bind_lock, &lockstate);
2684 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2689 path += strspn(path, ":;");
2690 while (*path != '\0') {
2694 len = strcspn(path, ":;");
2695 res = callback(path, len, arg);
2701 path += strspn(path, ":;");
2707 struct try_library_args {
2715 try_library_path(const char *dir, size_t dirlen, void *param)
2717 struct try_library_args *arg;
2720 if (*dir == '/' || trust) {
2723 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2726 pathname = arg->buffer;
2727 strncpy(pathname, dir, dirlen);
2728 pathname[dirlen] = '/';
2729 strcpy(pathname + dirlen + 1, arg->name);
2731 dbg(" Trying \"%s\"", pathname);
2732 if (access(pathname, F_OK) == 0) { /* We found it */
2733 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2734 strcpy(pathname, arg->buffer);
2742 search_library_path(const char *name, const char *path)
2745 struct try_library_args arg;
2751 arg.namelen = strlen(name);
2752 arg.buffer = xmalloc(PATH_MAX);
2753 arg.buflen = PATH_MAX;
2755 p = path_enumerate(path, try_library_path, &arg);
2763 dlclose(void *handle)
2766 RtldLockState lockstate;
2768 wlock_acquire(rtld_bind_lock, &lockstate);
2769 root = dlcheck(handle);
2771 lock_release(rtld_bind_lock, &lockstate);
2774 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2777 /* Unreference the object and its dependencies. */
2778 root->dl_refcount--;
2780 if (root->refcount == 1) {
2782 * The object will be no longer referenced, so we must unload it.
2783 * First, call the fini functions.
2785 objlist_call_fini(&list_fini, root, &lockstate);
2789 /* Finish cleaning up the newly-unreferenced objects. */
2790 GDB_STATE(RT_DELETE,&root->linkmap);
2791 unload_object(root);
2792 GDB_STATE(RT_CONSISTENT,NULL);
2796 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2797 lock_release(rtld_bind_lock, &lockstate);
2804 char *msg = error_message;
2805 error_message = NULL;
2810 dlopen(const char *name, int mode)
2813 return (rtld_dlopen(name, -1, mode));
2817 fdlopen(int fd, int mode)
2820 return (rtld_dlopen(NULL, fd, mode));
2824 rtld_dlopen(const char *name, int fd, int mode)
2826 RtldLockState lockstate;
2829 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2830 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2831 if (ld_tracing != NULL) {
2832 rlock_acquire(rtld_bind_lock, &lockstate);
2833 if (sigsetjmp(lockstate.env, 0) != 0)
2834 lock_upgrade(rtld_bind_lock, &lockstate);
2835 environ = (char **)*get_program_var_addr("environ", &lockstate);
2836 lock_release(rtld_bind_lock, &lockstate);
2838 lo_flags = RTLD_LO_DLOPEN;
2839 if (mode & RTLD_NODELETE)
2840 lo_flags |= RTLD_LO_NODELETE;
2841 if (mode & RTLD_NOLOAD)
2842 lo_flags |= RTLD_LO_NOLOAD;
2843 if (ld_tracing != NULL)
2844 lo_flags |= RTLD_LO_TRACE;
2846 return (dlopen_object(name, fd, obj_main, lo_flags,
2847 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2851 dlopen_cleanup(Obj_Entry *obj)
2856 if (obj->refcount == 0)
2861 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2862 int mode, RtldLockState *lockstate)
2864 Obj_Entry **old_obj_tail;
2867 RtldLockState mlockstate;
2870 objlist_init(&initlist);
2872 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2873 wlock_acquire(rtld_bind_lock, &mlockstate);
2874 lockstate = &mlockstate;
2876 GDB_STATE(RT_ADD,NULL);
2878 old_obj_tail = obj_tail;
2880 if (name == NULL && fd == -1) {
2884 obj = load_object(name, fd, refobj, lo_flags);
2889 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2890 objlist_push_tail(&list_global, obj);
2891 if (*old_obj_tail != NULL) { /* We loaded something new. */
2892 assert(*old_obj_tail == obj);
2893 result = load_needed_objects(obj,
2894 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2898 result = rtld_verify_versions(&obj->dagmembers);
2899 if (result != -1 && ld_tracing)
2901 if (result == -1 || relocate_object_dag(obj,
2902 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2903 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2905 dlopen_cleanup(obj);
2907 } else if (lo_flags & RTLD_LO_EARLY) {
2909 * Do not call the init functions for early loaded
2910 * filtees. The image is still not initialized enough
2913 * Our object is found by the global object list and
2914 * will be ordered among all init calls done right
2915 * before transferring control to main.
2918 /* Make list of init functions to call. */
2919 initlist_add_objects(obj, &obj->next, &initlist);
2922 * Process all no_delete objects here, given them own
2923 * DAGs to prevent their dependencies from being unloaded.
2924 * This has to be done after we have loaded all of the
2925 * dependencies, so that we do not miss any.
2928 process_nodelete(obj);
2931 * Bump the reference counts for objects on this DAG. If
2932 * this is the first dlopen() call for the object that was
2933 * already loaded as a dependency, initialize the dag
2939 if ((lo_flags & RTLD_LO_TRACE) != 0)
2942 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2943 obj->z_nodelete) && !obj->ref_nodel) {
2944 dbg("obj %s nodelete", obj->path);
2946 obj->z_nodelete = obj->ref_nodel = true;
2950 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2952 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2954 if (!(lo_flags & RTLD_LO_EARLY)) {
2955 map_stacks_exec(lockstate);
2958 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2959 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2961 objlist_clear(&initlist);
2962 dlopen_cleanup(obj);
2963 if (lockstate == &mlockstate)
2964 lock_release(rtld_bind_lock, lockstate);
2968 if (!(lo_flags & RTLD_LO_EARLY)) {
2969 /* Call the init functions. */
2970 objlist_call_init(&initlist, lockstate);
2972 objlist_clear(&initlist);
2973 if (lockstate == &mlockstate)
2974 lock_release(rtld_bind_lock, lockstate);
2977 trace_loaded_objects(obj);
2978 if (lockstate == &mlockstate)
2979 lock_release(rtld_bind_lock, lockstate);
2984 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2988 const Obj_Entry *obj, *defobj;
2991 RtldLockState lockstate;
2996 symlook_init(&req, name);
2998 req.flags = flags | SYMLOOK_IN_PLT;
2999 req.lockstate = &lockstate;
3001 rlock_acquire(rtld_bind_lock, &lockstate);
3002 if (sigsetjmp(lockstate.env, 0) != 0)
3003 lock_upgrade(rtld_bind_lock, &lockstate);
3004 if (handle == NULL || handle == RTLD_NEXT ||
3005 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3007 if ((obj = obj_from_addr(retaddr)) == NULL) {
3008 _rtld_error("Cannot determine caller's shared object");
3009 lock_release(rtld_bind_lock, &lockstate);
3012 if (handle == NULL) { /* Just the caller's shared object. */
3013 res = symlook_obj(&req, obj);
3016 defobj = req.defobj_out;
3018 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3019 handle == RTLD_SELF) { /* ... caller included */
3020 if (handle == RTLD_NEXT)
3022 for (; obj != NULL; obj = obj->next) {
3023 res = symlook_obj(&req, obj);
3026 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3028 defobj = req.defobj_out;
3029 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3035 * Search the dynamic linker itself, and possibly resolve the
3036 * symbol from there. This is how the application links to
3037 * dynamic linker services such as dlopen.
3039 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3040 res = symlook_obj(&req, &obj_rtld);
3041 if (res == 0 && is_exported(req.sym_out)) {
3043 defobj = req.defobj_out;
3047 assert(handle == RTLD_DEFAULT);
3048 res = symlook_default(&req, obj);
3050 defobj = req.defobj_out;
3055 if ((obj = dlcheck(handle)) == NULL) {
3056 lock_release(rtld_bind_lock, &lockstate);
3060 donelist_init(&donelist);
3061 if (obj->mainprog) {
3062 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3063 res = symlook_global(&req, &donelist);
3066 defobj = req.defobj_out;
3069 * Search the dynamic linker itself, and possibly resolve the
3070 * symbol from there. This is how the application links to
3071 * dynamic linker services such as dlopen.
3073 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3074 res = symlook_obj(&req, &obj_rtld);
3077 defobj = req.defobj_out;
3082 /* Search the whole DAG rooted at the given object. */
3083 res = symlook_list(&req, &obj->dagmembers, &donelist);
3086 defobj = req.defobj_out;
3092 lock_release(rtld_bind_lock, &lockstate);
3095 * The value required by the caller is derived from the value
3096 * of the symbol. For the ia64 architecture, we need to
3097 * construct a function descriptor which the caller can use to
3098 * call the function with the right 'gp' value. For other
3099 * architectures and for non-functions, the value is simply
3100 * the relocated value of the symbol.
3102 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3103 return (make_function_pointer(def, defobj));
3104 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3105 return (rtld_resolve_ifunc(defobj, def));
3106 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3108 ti.ti_module = defobj->tlsindex;
3109 ti.ti_offset = def->st_value;
3110 return (__tls_get_addr(&ti));
3112 return (defobj->relocbase + def->st_value);
3115 _rtld_error("Undefined symbol \"%s\"", name);
3116 lock_release(rtld_bind_lock, &lockstate);
3121 dlsym(void *handle, const char *name)
3123 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3128 dlfunc(void *handle, const char *name)
3135 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3141 dlvsym(void *handle, const char *name, const char *version)
3145 ventry.name = version;
3147 ventry.hash = elf_hash(version);
3149 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3154 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3156 const Obj_Entry *obj;
3157 RtldLockState lockstate;
3159 rlock_acquire(rtld_bind_lock, &lockstate);
3160 obj = obj_from_addr(addr);
3162 _rtld_error("No shared object contains address");
3163 lock_release(rtld_bind_lock, &lockstate);
3166 rtld_fill_dl_phdr_info(obj, phdr_info);
3167 lock_release(rtld_bind_lock, &lockstate);
3172 dladdr(const void *addr, Dl_info *info)
3174 const Obj_Entry *obj;
3177 unsigned long symoffset;
3178 RtldLockState lockstate;
3180 rlock_acquire(rtld_bind_lock, &lockstate);
3181 obj = obj_from_addr(addr);
3183 _rtld_error("No shared object contains address");
3184 lock_release(rtld_bind_lock, &lockstate);
3187 info->dli_fname = obj->path;
3188 info->dli_fbase = obj->mapbase;
3189 info->dli_saddr = NULL;
3190 info->dli_sname = NULL;
3193 * Walk the symbol list looking for the symbol whose address is
3194 * closest to the address sent in.
3196 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3197 def = obj->symtab + symoffset;
3200 * For skip the symbol if st_shndx is either SHN_UNDEF or
3203 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3207 * If the symbol is greater than the specified address, or if it
3208 * is further away from addr than the current nearest symbol,
3211 symbol_addr = obj->relocbase + def->st_value;
3212 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3215 /* Update our idea of the nearest symbol. */
3216 info->dli_sname = obj->strtab + def->st_name;
3217 info->dli_saddr = symbol_addr;
3220 if (info->dli_saddr == addr)
3223 lock_release(rtld_bind_lock, &lockstate);
3228 dlinfo(void *handle, int request, void *p)
3230 const Obj_Entry *obj;
3231 RtldLockState lockstate;
3234 rlock_acquire(rtld_bind_lock, &lockstate);
3236 if (handle == NULL || handle == RTLD_SELF) {
3239 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3240 if ((obj = obj_from_addr(retaddr)) == NULL)
3241 _rtld_error("Cannot determine caller's shared object");
3243 obj = dlcheck(handle);
3246 lock_release(rtld_bind_lock, &lockstate);
3252 case RTLD_DI_LINKMAP:
3253 *((struct link_map const **)p) = &obj->linkmap;
3255 case RTLD_DI_ORIGIN:
3256 error = rtld_dirname(obj->path, p);
3259 case RTLD_DI_SERINFOSIZE:
3260 case RTLD_DI_SERINFO:
3261 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3265 _rtld_error("Invalid request %d passed to dlinfo()", request);
3269 lock_release(rtld_bind_lock, &lockstate);
3275 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3278 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3279 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
3280 STAILQ_FIRST(&obj->names)->name : obj->path;
3281 phdr_info->dlpi_phdr = obj->phdr;
3282 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3283 phdr_info->dlpi_tls_modid = obj->tlsindex;
3284 phdr_info->dlpi_tls_data = obj->tlsinit;
3285 phdr_info->dlpi_adds = obj_loads;
3286 phdr_info->dlpi_subs = obj_loads - obj_count;
3290 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3292 struct dl_phdr_info phdr_info;
3293 const Obj_Entry *obj;
3294 RtldLockState bind_lockstate, phdr_lockstate;
3297 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3298 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3302 for (obj = obj_list; obj != NULL; obj = obj->next) {
3303 rtld_fill_dl_phdr_info(obj, &phdr_info);
3304 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3308 lock_release(rtld_bind_lock, &bind_lockstate);
3309 lock_release(rtld_phdr_lock, &phdr_lockstate);
3315 fill_search_info(const char *dir, size_t dirlen, void *param)
3317 struct fill_search_info_args *arg;
3321 if (arg->request == RTLD_DI_SERINFOSIZE) {
3322 arg->serinfo->dls_cnt ++;
3323 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3325 struct dl_serpath *s_entry;
3327 s_entry = arg->serpath;
3328 s_entry->dls_name = arg->strspace;
3329 s_entry->dls_flags = arg->flags;
3331 strncpy(arg->strspace, dir, dirlen);
3332 arg->strspace[dirlen] = '\0';
3334 arg->strspace += dirlen + 1;
3342 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3344 struct dl_serinfo _info;
3345 struct fill_search_info_args args;
3347 args.request = RTLD_DI_SERINFOSIZE;
3348 args.serinfo = &_info;
3350 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3353 path_enumerate(obj->rpath, fill_search_info, &args);
3354 path_enumerate(ld_library_path, fill_search_info, &args);
3355 path_enumerate(obj->runpath, fill_search_info, &args);
3356 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3357 if (!obj->z_nodeflib)
3358 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3361 if (request == RTLD_DI_SERINFOSIZE) {
3362 info->dls_size = _info.dls_size;
3363 info->dls_cnt = _info.dls_cnt;
3367 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3368 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3372 args.request = RTLD_DI_SERINFO;
3373 args.serinfo = info;
3374 args.serpath = &info->dls_serpath[0];
3375 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3377 args.flags = LA_SER_RUNPATH;
3378 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3381 args.flags = LA_SER_LIBPATH;
3382 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3385 args.flags = LA_SER_RUNPATH;
3386 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3389 args.flags = LA_SER_CONFIG;
3390 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3394 args.flags = LA_SER_DEFAULT;
3395 if (!obj->z_nodeflib &&
3396 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3402 rtld_dirname(const char *path, char *bname)
3406 /* Empty or NULL string gets treated as "." */
3407 if (path == NULL || *path == '\0') {
3413 /* Strip trailing slashes */
3414 endp = path + strlen(path) - 1;
3415 while (endp > path && *endp == '/')
3418 /* Find the start of the dir */
3419 while (endp > path && *endp != '/')
3422 /* Either the dir is "/" or there are no slashes */
3424 bname[0] = *endp == '/' ? '/' : '.';
3430 } while (endp > path && *endp == '/');
3433 if (endp - path + 2 > PATH_MAX)
3435 _rtld_error("Filename is too long: %s", path);
3439 strncpy(bname, path, endp - path + 1);
3440 bname[endp - path + 1] = '\0';
3445 rtld_dirname_abs(const char *path, char *base)
3447 char base_rel[PATH_MAX];
3449 if (rtld_dirname(path, base) == -1)
3453 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3454 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3455 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3457 strcpy(base, base_rel);
3462 linkmap_add(Obj_Entry *obj)
3464 struct link_map *l = &obj->linkmap;
3465 struct link_map *prev;
3467 obj->linkmap.l_name = obj->path;
3468 obj->linkmap.l_addr = obj->mapbase;
3469 obj->linkmap.l_ld = obj->dynamic;
3471 /* GDB needs load offset on MIPS to use the symbols */
3472 obj->linkmap.l_offs = obj->relocbase;
3475 if (r_debug.r_map == NULL) {
3481 * Scan to the end of the list, but not past the entry for the
3482 * dynamic linker, which we want to keep at the very end.
3484 for (prev = r_debug.r_map;
3485 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3486 prev = prev->l_next)
3489 /* Link in the new entry. */
3491 l->l_next = prev->l_next;
3492 if (l->l_next != NULL)
3493 l->l_next->l_prev = l;
3498 linkmap_delete(Obj_Entry *obj)
3500 struct link_map *l = &obj->linkmap;
3502 if (l->l_prev == NULL) {
3503 if ((r_debug.r_map = l->l_next) != NULL)
3504 l->l_next->l_prev = NULL;
3508 if ((l->l_prev->l_next = l->l_next) != NULL)
3509 l->l_next->l_prev = l->l_prev;
3513 * Function for the debugger to set a breakpoint on to gain control.
3515 * The two parameters allow the debugger to easily find and determine
3516 * what the runtime loader is doing and to whom it is doing it.
3518 * When the loadhook trap is hit (r_debug_state, set at program
3519 * initialization), the arguments can be found on the stack:
3521 * +8 struct link_map *m
3522 * +4 struct r_debug *rd
3526 r_debug_state(struct r_debug* rd, struct link_map *m)
3529 * The following is a hack to force the compiler to emit calls to
3530 * this function, even when optimizing. If the function is empty,
3531 * the compiler is not obliged to emit any code for calls to it,
3532 * even when marked __noinline. However, gdb depends on those
3535 __asm __volatile("" : : : "memory");
3539 * Get address of the pointer variable in the main program.
3540 * Prefer non-weak symbol over the weak one.
3542 static const void **
3543 get_program_var_addr(const char *name, RtldLockState *lockstate)
3548 symlook_init(&req, name);
3549 req.lockstate = lockstate;
3550 donelist_init(&donelist);
3551 if (symlook_global(&req, &donelist) != 0)
3553 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3554 return ((const void **)make_function_pointer(req.sym_out,
3556 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3557 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3559 return ((const void **)(req.defobj_out->relocbase + req.sym_out->st_value));
3563 * Set a pointer variable in the main program to the given value. This
3564 * is used to set key variables such as "environ" before any of the
3565 * init functions are called.
3568 set_program_var(const char *name, const void *value)
3572 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3573 dbg("\"%s\": *%p <-- %p", name, addr, value);
3579 * Search the global objects, including dependencies and main object,
3580 * for the given symbol.
3583 symlook_global(SymLook *req, DoneList *donelist)
3586 const Objlist_Entry *elm;
3589 symlook_init_from_req(&req1, req);
3591 /* Search all objects loaded at program start up. */
3592 if (req->defobj_out == NULL ||
3593 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3594 res = symlook_list(&req1, &list_main, donelist);
3595 if (res == 0 && (req->defobj_out == NULL ||
3596 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3597 req->sym_out = req1.sym_out;
3598 req->defobj_out = req1.defobj_out;
3599 assert(req->defobj_out != NULL);
3603 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3604 STAILQ_FOREACH(elm, &list_global, link) {
3605 if (req->defobj_out != NULL &&
3606 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3608 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3609 if (res == 0 && (req->defobj_out == NULL ||
3610 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3611 req->sym_out = req1.sym_out;
3612 req->defobj_out = req1.defobj_out;
3613 assert(req->defobj_out != NULL);
3617 return (req->sym_out != NULL ? 0 : ESRCH);
3621 * This is a special version of getenv which is far more efficient
3622 * at finding LD_ environment vars.
3626 _getenv_ld(const char *id)
3630 int idlen = strlen(id);
3632 if (ld_index == LD_ARY_CACHE)
3634 if (ld_index == 0) {
3635 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) {
3636 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_')
3643 for (i = ld_index - 1; i >= 0; --i) {
3644 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=')
3645 return(ld_ary[i] + idlen + 1);
3651 * Given a symbol name in a referencing object, find the corresponding
3652 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3653 * no definition was found. Returns a pointer to the Obj_Entry of the
3654 * defining object via the reference parameter DEFOBJ_OUT.
3657 symlook_default(SymLook *req, const Obj_Entry *refobj)
3660 const Objlist_Entry *elm;
3664 donelist_init(&donelist);
3665 symlook_init_from_req(&req1, req);
3667 /* Look first in the referencing object if linked symbolically. */
3668 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3669 res = symlook_obj(&req1, refobj);
3671 req->sym_out = req1.sym_out;
3672 req->defobj_out = req1.defobj_out;
3673 assert(req->defobj_out != NULL);
3677 symlook_global(req, &donelist);
3679 /* Search all dlopened DAGs containing the referencing object. */
3680 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3681 if (req->sym_out != NULL &&
3682 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3684 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3685 if (res == 0 && (req->sym_out == NULL ||
3686 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3687 req->sym_out = req1.sym_out;
3688 req->defobj_out = req1.defobj_out;
3689 assert(req->defobj_out != NULL);
3694 * Search the dynamic linker itself, and possibly resolve the
3695 * symbol from there. This is how the application links to
3696 * dynamic linker services such as dlopen. Only the values listed
3697 * in the "exports" array can be resolved from the dynamic linker.
3699 if (req->sym_out == NULL ||
3700 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3701 res = symlook_obj(&req1, &obj_rtld);
3702 if (res == 0 && is_exported(req1.sym_out)) {
3703 req->sym_out = req1.sym_out;
3704 req->defobj_out = req1.defobj_out;
3705 assert(req->defobj_out != NULL);
3709 return (req->sym_out != NULL ? 0 : ESRCH);
3713 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3716 const Obj_Entry *defobj;
3717 const Objlist_Entry *elm;
3723 STAILQ_FOREACH(elm, objlist, link) {
3724 if (donelist_check(dlp, elm->obj))
3726 symlook_init_from_req(&req1, req);
3727 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3728 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3730 defobj = req1.defobj_out;
3731 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3738 req->defobj_out = defobj;
3745 * Search the chain of DAGS cointed to by the given Needed_Entry
3746 * for a symbol of the given name. Each DAG is scanned completely
3747 * before advancing to the next one. Returns a pointer to the symbol,
3748 * or NULL if no definition was found.
3751 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3754 const Needed_Entry *n;
3755 const Obj_Entry *defobj;
3761 symlook_init_from_req(&req1, req);
3762 for (n = needed; n != NULL; n = n->next) {
3763 if (n->obj == NULL ||
3764 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3766 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3768 defobj = req1.defobj_out;
3769 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3775 req->defobj_out = defobj;
3782 * Search the symbol table of a single shared object for a symbol of
3783 * the given name and version, if requested. Returns a pointer to the
3784 * symbol, or NULL if no definition was found. If the object is
3785 * filter, return filtered symbol from filtee.
3787 * The symbol's hash value is passed in for efficiency reasons; that
3788 * eliminates many recomputations of the hash value.
3791 symlook_obj(SymLook *req, const Obj_Entry *obj)
3795 int flags, res, mres;
3798 * If there is at least one valid hash at this point, we prefer to
3799 * use the faster GNU version if available.
3801 if (obj->valid_hash_gnu)
3802 mres = symlook_obj1_gnu(req, obj);
3803 else if (obj->valid_hash_sysv)
3804 mres = symlook_obj1_sysv(req, obj);
3809 if (obj->needed_filtees != NULL) {
3810 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3811 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3812 donelist_init(&donelist);
3813 symlook_init_from_req(&req1, req);
3814 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3816 req->sym_out = req1.sym_out;
3817 req->defobj_out = req1.defobj_out;
3821 if (obj->needed_aux_filtees != NULL) {
3822 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3823 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3824 donelist_init(&donelist);
3825 symlook_init_from_req(&req1, req);
3826 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3828 req->sym_out = req1.sym_out;
3829 req->defobj_out = req1.defobj_out;
3837 /* Symbol match routine common to both hash functions */
3839 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3840 const unsigned long symnum)
3843 const Elf_Sym *symp;
3846 symp = obj->symtab + symnum;
3847 strp = obj->strtab + symp->st_name;
3849 switch (ELF_ST_TYPE(symp->st_info)) {
3855 if (symp->st_value == 0)
3859 if (symp->st_shndx != SHN_UNDEF)
3861 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3862 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3868 if (strcmp(req->name, strp) != 0)
3871 if (req->ventry == NULL) {
3872 if (obj->versyms != NULL) {
3873 verndx = VER_NDX(obj->versyms[symnum]);
3874 if (verndx > obj->vernum) {
3876 "%s: symbol %s references wrong version %d",
3877 obj->path, obj->strtab + symnum, verndx);
3881 * If we are not called from dlsym (i.e. this
3882 * is a normal relocation from unversioned
3883 * binary), accept the symbol immediately if
3884 * it happens to have first version after this
3885 * shared object became versioned. Otherwise,
3886 * if symbol is versioned and not hidden,
3887 * remember it. If it is the only symbol with
3888 * this name exported by the shared object, it
3889 * will be returned as a match by the calling
3890 * function. If symbol is global (verndx < 2)
3891 * accept it unconditionally.
3893 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3894 verndx == VER_NDX_GIVEN) {
3895 result->sym_out = symp;
3898 else if (verndx >= VER_NDX_GIVEN) {
3899 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3901 if (result->vsymp == NULL)
3902 result->vsymp = symp;
3908 result->sym_out = symp;
3911 if (obj->versyms == NULL) {
3912 if (object_match_name(obj, req->ventry->name)) {
3913 _rtld_error("%s: object %s should provide version %s "
3914 "for symbol %s", obj_rtld.path, obj->path,
3915 req->ventry->name, obj->strtab + symnum);
3919 verndx = VER_NDX(obj->versyms[symnum]);
3920 if (verndx > obj->vernum) {
3921 _rtld_error("%s: symbol %s references wrong version %d",
3922 obj->path, obj->strtab + symnum, verndx);
3925 if (obj->vertab[verndx].hash != req->ventry->hash ||
3926 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3928 * Version does not match. Look if this is a
3929 * global symbol and if it is not hidden. If
3930 * global symbol (verndx < 2) is available,
3931 * use it. Do not return symbol if we are
3932 * called by dlvsym, because dlvsym looks for
3933 * a specific version and default one is not
3934 * what dlvsym wants.
3936 if ((req->flags & SYMLOOK_DLSYM) ||
3937 (verndx >= VER_NDX_GIVEN) ||
3938 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3942 result->sym_out = symp;
3947 * Search for symbol using SysV hash function.
3948 * obj->buckets is known not to be NULL at this point; the test for this was
3949 * performed with the obj->valid_hash_sysv assignment.
3952 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
3954 unsigned long symnum;
3955 Sym_Match_Result matchres;
3957 matchres.sym_out = NULL;
3958 matchres.vsymp = NULL;
3959 matchres.vcount = 0;
3961 for (symnum = obj->buckets[req->hash % obj->nbuckets];
3962 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3963 if (symnum >= obj->nchains)
3964 return (ESRCH); /* Bad object */
3966 if (matched_symbol(req, obj, &matchres, symnum)) {
3967 req->sym_out = matchres.sym_out;
3968 req->defobj_out = obj;
3972 if (matchres.vcount == 1) {
3973 req->sym_out = matchres.vsymp;
3974 req->defobj_out = obj;
3980 /* Search for symbol using GNU hash function */
3982 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
3984 Elf_Addr bloom_word;
3985 const Elf32_Word *hashval;
3987 Sym_Match_Result matchres;
3988 unsigned int h1, h2;
3989 unsigned long symnum;
3991 matchres.sym_out = NULL;
3992 matchres.vsymp = NULL;
3993 matchres.vcount = 0;
3995 /* Pick right bitmask word from Bloom filter array */
3996 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
3997 obj->maskwords_bm_gnu];
3999 /* Calculate modulus word size of gnu hash and its derivative */
4000 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4001 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4003 /* Filter out the "definitely not in set" queries */
4004 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4007 /* Locate hash chain and corresponding value element*/
4008 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4011 hashval = &obj->chain_zero_gnu[bucket];
4013 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4014 symnum = hashval - obj->chain_zero_gnu;
4015 if (matched_symbol(req, obj, &matchres, symnum)) {
4016 req->sym_out = matchres.sym_out;
4017 req->defobj_out = obj;
4021 } while ((*hashval++ & 1) == 0);
4022 if (matchres.vcount == 1) {
4023 req->sym_out = matchres.vsymp;
4024 req->defobj_out = obj;
4031 trace_loaded_objects(Obj_Entry *obj)
4033 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4036 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4039 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4040 fmt1 = "\t%o => %p (%x)\n";
4042 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4043 fmt2 = "\t%o (%x)\n";
4045 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL");
4047 for (; obj; obj = obj->next) {
4048 Needed_Entry *needed;
4052 if (list_containers && obj->needed != NULL)
4053 rtld_printf("%s:\n", obj->path);
4054 for (needed = obj->needed; needed; needed = needed->next) {
4055 if (needed->obj != NULL) {
4056 if (needed->obj->traced && !list_containers)
4058 needed->obj->traced = true;
4059 path = needed->obj->path;
4063 name = (char *)obj->strtab + needed->name;
4064 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4066 fmt = is_lib ? fmt1 : fmt2;
4067 while ((c = *fmt++) != '\0') {
4093 rtld_putstr(main_local);
4096 rtld_putstr(obj_main->path);
4105 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4118 * Unload a dlopened object and its dependencies from memory and from
4119 * our data structures. It is assumed that the DAG rooted in the
4120 * object has already been unreferenced, and that the object has a
4121 * reference count of 0.
4124 unload_object(Obj_Entry *root)
4129 assert(root->refcount == 0);
4132 * Pass over the DAG removing unreferenced objects from
4133 * appropriate lists.
4135 unlink_object(root);
4137 /* Unmap all objects that are no longer referenced. */
4138 linkp = &obj_list->next;
4139 while ((obj = *linkp) != NULL) {
4140 if (obj->refcount == 0) {
4141 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4143 dbg("unloading \"%s\"", obj->path);
4144 unload_filtees(root);
4145 munmap(obj->mapbase, obj->mapsize);
4146 linkmap_delete(obj);
4157 unlink_object(Obj_Entry *root)
4161 if (root->refcount == 0) {
4162 /* Remove the object from the RTLD_GLOBAL list. */
4163 objlist_remove(&list_global, root);
4165 /* Remove the object from all objects' DAG lists. */
4166 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4167 objlist_remove(&elm->obj->dldags, root);
4168 if (elm->obj != root)
4169 unlink_object(elm->obj);
4175 ref_dag(Obj_Entry *root)
4179 assert(root->dag_inited);
4180 STAILQ_FOREACH(elm, &root->dagmembers, link)
4181 elm->obj->refcount++;
4185 unref_dag(Obj_Entry *root)
4189 assert(root->dag_inited);
4190 STAILQ_FOREACH(elm, &root->dagmembers, link)
4191 elm->obj->refcount--;
4195 * Common code for MD __tls_get_addr().
4198 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
4200 Elf_Addr* dtv = *dtvp;
4201 RtldLockState lockstate;
4203 /* Check dtv generation in case new modules have arrived */
4204 if (dtv[0] != tls_dtv_generation) {
4208 wlock_acquire(rtld_bind_lock, &lockstate);
4209 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4211 if (to_copy > tls_max_index)
4212 to_copy = tls_max_index;
4213 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4214 newdtv[0] = tls_dtv_generation;
4215 newdtv[1] = tls_max_index;
4217 lock_release(rtld_bind_lock, &lockstate);
4218 dtv = *dtvp = newdtv;
4221 /* Dynamically allocate module TLS if necessary */
4222 if (!dtv[index + 1]) {
4223 /* Signal safe, wlock will block out signals. */
4224 wlock_acquire(rtld_bind_lock, &lockstate);
4225 if (!dtv[index + 1])
4226 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4227 lock_release(rtld_bind_lock, &lockstate);
4229 return (void*) (dtv[index + 1] + offset);
4232 #if defined(RTLD_STATIC_TLS_VARIANT_II)
4235 * Allocate the static TLS area. Return a pointer to the TCB. The
4236 * static area is based on negative offsets relative to the tcb.
4238 * The TCB contains an errno pointer for the system call layer, but because
4239 * we are the RTLD we really have no idea how the caller was compiled so
4240 * the information has to be passed in. errno can either be:
4242 * type 0 errno is a simple non-TLS global pointer.
4243 * (special case for e.g. libc_rtld)
4244 * type 1 errno accessed by GOT entry (dynamically linked programs)
4245 * type 2 errno accessed by %gs:OFFSET (statically linked programs)
4248 allocate_tls(Obj_Entry *objs)
4253 struct tls_tcb *tcb;
4258 * Allocate the new TCB. static TLS storage is placed just before the
4259 * TCB to support the %gs:OFFSET (negative offset) model.
4261 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
4262 ~RTLD_STATIC_TLS_ALIGN_MASK;
4263 tcb = malloc(data_size + sizeof(*tcb));
4264 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */
4266 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr);
4267 dtv = malloc(dtv_size);
4268 bzero(dtv, dtv_size);
4270 #ifdef RTLD_TCB_HAS_SELF_POINTER
4271 tcb->tcb_self = tcb;
4274 tcb->tcb_pthread = NULL;
4276 dtv[0] = tls_dtv_generation;
4277 dtv[1] = tls_max_index;
4279 for (obj = objs; obj; obj = obj->next) {
4280 if (obj->tlsoffset) {
4281 addr = (Elf_Addr)tcb - obj->tlsoffset;
4282 memset((void *)(addr + obj->tlsinitsize),
4283 0, obj->tlssize - obj->tlsinitsize);
4285 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4286 dtv[obj->tlsindex + 1] = addr;
4293 free_tls(struct tls_tcb *tcb)
4297 Elf_Addr tls_start, tls_end;
4300 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
4301 ~RTLD_STATIC_TLS_ALIGN_MASK;
4305 tls_end = (Elf_Addr)tcb;
4306 tls_start = (Elf_Addr)tcb - data_size;
4307 for (i = 0; i < dtv_size; i++) {
4308 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) {
4309 free((void *)dtv[i+2]);
4313 free((void*) tls_start);
4317 #error "Unsupported TLS layout"
4321 * Allocate TLS block for module with given index.
4324 allocate_module_tls(int index)
4329 for (obj = obj_list; obj; obj = obj->next) {
4330 if (obj->tlsindex == index)
4334 _rtld_error("Can't find module with TLS index %d", index);
4338 p = malloc(obj->tlssize);
4340 _rtld_error("Cannot allocate TLS block for index %d", index);
4343 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4344 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4350 allocate_tls_offset(Obj_Entry *obj)
4357 if (obj->tlssize == 0) {
4358 obj->tls_done = true;
4362 if (obj->tlsindex == 1)
4363 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4365 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4366 obj->tlssize, obj->tlsalign);
4369 * If we have already fixed the size of the static TLS block, we
4370 * must stay within that size. When allocating the static TLS, we
4371 * leave a small amount of space spare to be used for dynamically
4372 * loading modules which use static TLS.
4374 if (tls_static_space) {
4375 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4379 tls_last_offset = obj->tlsoffset = off;
4380 tls_last_size = obj->tlssize;
4381 obj->tls_done = true;
4387 free_tls_offset(Obj_Entry *obj)
4389 #ifdef RTLD_STATIC_TLS_VARIANT_II
4391 * If we were the last thing to allocate out of the static TLS
4392 * block, we give our space back to the 'allocator'. This is a
4393 * simplistic workaround to allow libGL.so.1 to be loaded and
4394 * unloaded multiple times. We only handle the Variant II
4395 * mechanism for now - this really needs a proper allocator.
4397 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4398 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4399 tls_last_offset -= obj->tlssize;
4406 _rtld_allocate_tls(void)
4408 struct tls_tcb *new_tcb;
4409 RtldLockState lockstate;
4411 wlock_acquire(rtld_bind_lock, &lockstate);
4412 new_tcb = allocate_tls(obj_list);
4413 lock_release(rtld_bind_lock, &lockstate);
4418 _rtld_free_tls(struct tls_tcb *tcb)
4420 RtldLockState lockstate;
4422 wlock_acquire(rtld_bind_lock, &lockstate);
4424 lock_release(rtld_bind_lock, &lockstate);
4428 object_add_name(Obj_Entry *obj, const char *name)
4434 entry = malloc(sizeof(Name_Entry) + len);
4436 if (entry != NULL) {
4437 strcpy(entry->name, name);
4438 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4443 object_match_name(const Obj_Entry *obj, const char *name)
4447 STAILQ_FOREACH(entry, &obj->names, link) {
4448 if (strcmp(name, entry->name) == 0)
4455 locate_dependency(const Obj_Entry *obj, const char *name)
4457 const Objlist_Entry *entry;
4458 const Needed_Entry *needed;
4460 STAILQ_FOREACH(entry, &list_main, link) {
4461 if (object_match_name(entry->obj, name))
4465 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4466 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4467 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4469 * If there is DT_NEEDED for the name we are looking for,
4470 * we are all set. Note that object might not be found if
4471 * dependency was not loaded yet, so the function can
4472 * return NULL here. This is expected and handled
4473 * properly by the caller.
4475 return (needed->obj);
4478 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4484 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4485 const Elf_Vernaux *vna)
4487 const Elf_Verdef *vd;
4488 const char *vername;
4490 vername = refobj->strtab + vna->vna_name;
4491 vd = depobj->verdef;
4493 _rtld_error("%s: version %s required by %s not defined",
4494 depobj->path, vername, refobj->path);
4498 if (vd->vd_version != VER_DEF_CURRENT) {
4499 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4500 depobj->path, vd->vd_version);
4503 if (vna->vna_hash == vd->vd_hash) {
4504 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4505 ((char *)vd + vd->vd_aux);
4506 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4509 if (vd->vd_next == 0)
4511 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4513 if (vna->vna_flags & VER_FLG_WEAK)
4515 _rtld_error("%s: version %s required by %s not found",
4516 depobj->path, vername, refobj->path);
4521 rtld_verify_object_versions(Obj_Entry *obj)
4523 const Elf_Verneed *vn;
4524 const Elf_Verdef *vd;
4525 const Elf_Verdaux *vda;
4526 const Elf_Vernaux *vna;
4527 const Obj_Entry *depobj;
4528 int maxvernum, vernum;
4530 if (obj->ver_checked)
4532 obj->ver_checked = true;
4536 * Walk over defined and required version records and figure out
4537 * max index used by any of them. Do very basic sanity checking
4541 while (vn != NULL) {
4542 if (vn->vn_version != VER_NEED_CURRENT) {
4543 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4544 obj->path, vn->vn_version);
4547 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4549 vernum = VER_NEED_IDX(vna->vna_other);
4550 if (vernum > maxvernum)
4552 if (vna->vna_next == 0)
4554 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4556 if (vn->vn_next == 0)
4558 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4562 while (vd != NULL) {
4563 if (vd->vd_version != VER_DEF_CURRENT) {
4564 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4565 obj->path, vd->vd_version);
4568 vernum = VER_DEF_IDX(vd->vd_ndx);
4569 if (vernum > maxvernum)
4571 if (vd->vd_next == 0)
4573 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4580 * Store version information in array indexable by version index.
4581 * Verify that object version requirements are satisfied along the
4584 obj->vernum = maxvernum + 1;
4585 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4588 while (vd != NULL) {
4589 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4590 vernum = VER_DEF_IDX(vd->vd_ndx);
4591 assert(vernum <= maxvernum);
4592 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4593 obj->vertab[vernum].hash = vd->vd_hash;
4594 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4595 obj->vertab[vernum].file = NULL;
4596 obj->vertab[vernum].flags = 0;
4598 if (vd->vd_next == 0)
4600 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4604 while (vn != NULL) {
4605 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4608 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4610 if (check_object_provided_version(obj, depobj, vna))
4612 vernum = VER_NEED_IDX(vna->vna_other);
4613 assert(vernum <= maxvernum);
4614 obj->vertab[vernum].hash = vna->vna_hash;
4615 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4616 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4617 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4618 VER_INFO_HIDDEN : 0;
4619 if (vna->vna_next == 0)
4621 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4623 if (vn->vn_next == 0)
4625 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4631 rtld_verify_versions(const Objlist *objlist)
4633 Objlist_Entry *entry;
4637 STAILQ_FOREACH(entry, objlist, link) {
4639 * Skip dummy objects or objects that have their version requirements
4642 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4644 if (rtld_verify_object_versions(entry->obj) == -1) {
4646 if (ld_tracing == NULL)
4650 if (rc == 0 || ld_tracing != NULL)
4651 rc = rtld_verify_object_versions(&obj_rtld);
4656 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4661 vernum = VER_NDX(obj->versyms[symnum]);
4662 if (vernum >= obj->vernum) {
4663 _rtld_error("%s: symbol %s has wrong verneed value %d",
4664 obj->path, obj->strtab + symnum, vernum);
4665 } else if (obj->vertab[vernum].hash != 0) {
4666 return &obj->vertab[vernum];
4673 _rtld_get_stack_prot(void)
4676 return (stack_prot);
4680 map_stacks_exec(RtldLockState *lockstate)
4684 * Stack protection must be implemented in the kernel before the dynamic
4685 * linker can handle PT_GNU_STACK sections.
4686 * The following is the FreeBSD implementation of map_stacks_exec()
4687 * void (*thr_map_stacks_exec)(void);
4689 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4691 * thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4692 * get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4693 * if (thr_map_stacks_exec != NULL) {
4694 * stack_prot |= PROT_EXEC;
4695 * thr_map_stacks_exec();
4701 symlook_init(SymLook *dst, const char *name)
4704 bzero(dst, sizeof(*dst));
4706 dst->hash = elf_hash(name);
4707 dst->hash_gnu = gnu_hash(name);
4711 symlook_init_from_req(SymLook *dst, const SymLook *src)
4714 dst->name = src->name;
4715 dst->hash = src->hash;
4716 dst->hash_gnu = src->hash_gnu;
4717 dst->ventry = src->ventry;
4718 dst->flags = src->flags;
4719 dst->defobj_out = NULL;
4720 dst->sym_out = NULL;
4721 dst->lockstate = src->lockstate;
4724 #ifdef ENABLE_OSRELDATE
4726 * Overrides for libc_pic-provided functions.
4730 __getosreldate(void)
4740 oid[1] = KERN_OSRELDATE;
4742 len = sizeof(osrel);
4743 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4744 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4751 * No unresolved symbols for rtld.
4754 __pthread_cxa_finalize(struct dl_phdr_info *a)
4759 rtld_strerror(int errnum)
4762 if (errnum < 0 || errnum >= sys_nerr)
4763 return ("Unknown error");
4764 return (sys_errlist[errnum]);