2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
37 #include <sys/param.h>
38 #include <sys/mount.h>
41 #include <sys/sysctl.h>
43 #include <sys/utsname.h>
44 #include <sys/ktrace.h>
60 #include "rtld_printf.h"
64 #define PATH_RTLD "/libexec/ld-elf.so.1"
66 #define PATH_RTLD "/libexec/ld-elf32.so.1"
70 typedef void (*func_ptr_type)();
71 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
74 * Function declarations.
76 static const char *basename(const char *);
77 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
78 const Elf_Dyn **, const Elf_Dyn **);
79 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
81 static void digest_dynamic(Obj_Entry *, int);
82 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
83 static Obj_Entry *dlcheck(void *);
84 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
85 int lo_flags, int mode, RtldLockState *lockstate);
86 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
87 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
88 static bool donelist_check(DoneList *, const Obj_Entry *);
89 static void errmsg_restore(char *);
90 static char *errmsg_save(void);
91 static void *fill_search_info(const char *, size_t, void *);
92 static char *find_library(const char *, const Obj_Entry *);
93 static const char *gethints(bool);
94 static void init_dag(Obj_Entry *);
95 static void init_pagesizes(Elf_Auxinfo **aux_info);
96 static void init_rtld(caddr_t, Elf_Auxinfo **);
97 static void initlist_add_neededs(Needed_Entry *, Objlist *);
98 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
99 static void linkmap_add(Obj_Entry *);
100 static void linkmap_delete(Obj_Entry *);
101 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
102 static void unload_filtees(Obj_Entry *);
103 static int load_needed_objects(Obj_Entry *, int);
104 static int load_preload_objects(void);
105 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
106 static void map_stacks_exec(RtldLockState *);
107 static int obj_enforce_relro(Obj_Entry *);
108 static Obj_Entry *obj_from_addr(const void *);
109 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
110 static void objlist_call_init(Objlist *, RtldLockState *);
111 static void objlist_clear(Objlist *);
112 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
113 static void objlist_init(Objlist *);
114 static void objlist_push_head(Objlist *, Obj_Entry *);
115 static void objlist_push_tail(Objlist *, Obj_Entry *);
116 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
117 static void objlist_remove(Objlist *, Obj_Entry *);
118 static void *path_enumerate(const char *, path_enum_proc, void *);
119 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
120 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
121 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
122 int flags, RtldLockState *lockstate);
123 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
125 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
126 int flags, RtldLockState *lockstate);
127 static int rtld_dirname(const char *, char *);
128 static int rtld_dirname_abs(const char *, char *);
129 static void *rtld_dlopen(const char *name, int fd, int mode);
130 static void rtld_exit(void);
131 static char *search_library_path(const char *, const char *);
132 static const void **get_program_var_addr(const char *, RtldLockState *);
133 static void set_program_var(const char *, const void *);
134 static int symlook_default(SymLook *, const Obj_Entry *refobj);
135 static int symlook_global(SymLook *, DoneList *);
136 static void symlook_init_from_req(SymLook *, const SymLook *);
137 static int symlook_list(SymLook *, const Objlist *, DoneList *);
138 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
139 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
140 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
141 static void trace_loaded_objects(Obj_Entry *);
142 static void unlink_object(Obj_Entry *);
143 static void unload_object(Obj_Entry *);
144 static void unref_dag(Obj_Entry *);
145 static void ref_dag(Obj_Entry *);
146 static char *origin_subst_one(Obj_Entry *, char *, const char *,
148 static char *origin_subst(Obj_Entry *, char *);
149 static bool obj_resolve_origin(Obj_Entry *obj);
150 static void preinit_main(void);
151 static int rtld_verify_versions(const Objlist *);
152 static int rtld_verify_object_versions(Obj_Entry *);
153 static void object_add_name(Obj_Entry *, const char *);
154 static int object_match_name(const Obj_Entry *, const char *);
155 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
156 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
157 struct dl_phdr_info *phdr_info);
158 static uint32_t gnu_hash(const char *);
159 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
160 const unsigned long);
162 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
163 void _r_debug_postinit(struct link_map *) __noinline __exported;
168 static char *error_message; /* Message for dlerror(), or NULL */
169 struct r_debug r_debug __exported; /* 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 char *ld_bind_now; /* Environment variable for immediate binding */
177 static char *ld_debug; /* Environment variable for debugging */
178 static char *ld_library_path; /* Environment variable for search path */
179 static char *ld_preload; /* Environment variable for libraries to
181 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
182 static char *ld_tracing; /* Called from ldd to print libs */
183 static char *ld_utrace; /* Use utrace() to log events. */
184 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
185 static Obj_Entry *obj_main; /* The main program shared object */
186 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
187 static unsigned int obj_count; /* Number of objects in obj_list */
188 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
190 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
191 STAILQ_HEAD_INITIALIZER(list_global);
192 static Objlist list_main = /* Objects loaded at program startup */
193 STAILQ_HEAD_INITIALIZER(list_main);
194 static Objlist list_fini = /* Objects needing fini() calls */
195 STAILQ_HEAD_INITIALIZER(list_fini);
197 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
199 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
201 extern Elf_Dyn _DYNAMIC;
202 #pragma weak _DYNAMIC
203 #ifndef RTLD_IS_DYNAMIC
204 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
207 int dlclose(void *) __exported;
208 char *dlerror(void) __exported;
209 void *dlopen(const char *, int) __exported;
210 void *fdlopen(int, int) __exported;
211 void *dlsym(void *, const char *) __exported;
212 dlfunc_t dlfunc(void *, const char *) __exported;
213 void *dlvsym(void *, const char *, const char *) __exported;
214 int dladdr(const void *, Dl_info *) __exported;
215 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
216 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
217 int dlinfo(void *, int , void *) __exported;
218 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
219 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
220 int _rtld_get_stack_prot(void) __exported;
221 int _rtld_is_dlopened(void *) __exported;
222 void _rtld_error(const char *, ...) __exported;
224 int npagesizes, osreldate;
227 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
229 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
230 static int max_stack_flags;
233 * Global declarations normally provided by crt1. The dynamic linker is
234 * not built with crt1, so we have to provide them ourselves.
240 * Used to pass argc, argv to init functions.
246 * Globals to control TLS allocation.
248 size_t tls_last_offset; /* Static TLS offset of last module */
249 size_t tls_last_size; /* Static TLS size of last module */
250 size_t tls_static_space; /* Static TLS space allocated */
251 size_t tls_static_max_align;
252 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
253 int tls_max_index = 1; /* Largest module index allocated */
255 bool ld_library_path_rpath = false;
258 * Fill in a DoneList with an allocation large enough to hold all of
259 * the currently-loaded objects. Keep this as a macro since it calls
260 * alloca and we want that to occur within the scope of the caller.
262 #define donelist_init(dlp) \
263 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
264 assert((dlp)->objs != NULL), \
265 (dlp)->num_alloc = obj_count, \
268 #define UTRACE_DLOPEN_START 1
269 #define UTRACE_DLOPEN_STOP 2
270 #define UTRACE_DLCLOSE_START 3
271 #define UTRACE_DLCLOSE_STOP 4
272 #define UTRACE_LOAD_OBJECT 5
273 #define UTRACE_UNLOAD_OBJECT 6
274 #define UTRACE_ADD_RUNDEP 7
275 #define UTRACE_PRELOAD_FINISHED 8
276 #define UTRACE_INIT_CALL 9
277 #define UTRACE_FINI_CALL 10
278 #define UTRACE_DLSYM_START 11
279 #define UTRACE_DLSYM_STOP 12
282 char sig[4]; /* 'RTLD' */
285 void *mapbase; /* Used for 'parent' and 'init/fini' */
287 int refcnt; /* Used for 'mode' */
288 char name[MAXPATHLEN];
291 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
292 if (ld_utrace != NULL) \
293 ld_utrace_log(e, h, mb, ms, r, n); \
297 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
298 int refcnt, const char *name)
300 struct utrace_rtld ut;
308 ut.mapbase = mapbase;
309 ut.mapsize = mapsize;
311 bzero(ut.name, sizeof(ut.name));
313 strlcpy(ut.name, name, sizeof(ut.name));
314 utrace(&ut, sizeof(ut));
318 * Main entry point for dynamic linking. The first argument is the
319 * stack pointer. The stack is expected to be laid out as described
320 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
321 * Specifically, the stack pointer points to a word containing
322 * ARGC. Following that in the stack is a null-terminated sequence
323 * of pointers to argument strings. Then comes a null-terminated
324 * sequence of pointers to environment strings. Finally, there is a
325 * sequence of "auxiliary vector" entries.
327 * The second argument points to a place to store the dynamic linker's
328 * exit procedure pointer and the third to a place to store the main
331 * The return value is the main program's entry point.
334 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
336 Elf_Auxinfo *aux_info[AT_COUNT];
344 Objlist_Entry *entry;
346 Obj_Entry *preload_tail;
347 Obj_Entry *last_interposer;
349 RtldLockState lockstate;
350 char *library_path_rpath;
355 * On entry, the dynamic linker itself has not been relocated yet.
356 * Be very careful not to reference any global data until after
357 * init_rtld has returned. It is OK to reference file-scope statics
358 * and string constants, and to call static and global functions.
361 /* Find the auxiliary vector on the stack. */
364 sp += argc + 1; /* Skip over arguments and NULL terminator */
366 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
368 aux = (Elf_Auxinfo *) sp;
370 /* Digest the auxiliary vector. */
371 for (i = 0; i < AT_COUNT; i++)
373 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
374 if (auxp->a_type < AT_COUNT)
375 aux_info[auxp->a_type] = auxp;
378 /* Initialize and relocate ourselves. */
379 assert(aux_info[AT_BASE] != NULL);
380 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
382 __progname = obj_rtld.path;
383 argv0 = argv[0] != NULL ? argv[0] : "(null)";
388 if (aux_info[AT_CANARY] != NULL &&
389 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
390 i = aux_info[AT_CANARYLEN]->a_un.a_val;
391 if (i > sizeof(__stack_chk_guard))
392 i = sizeof(__stack_chk_guard);
393 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
398 len = sizeof(__stack_chk_guard);
399 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
400 len != sizeof(__stack_chk_guard)) {
401 /* If sysctl was unsuccessful, use the "terminator canary". */
402 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
403 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
404 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
405 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
409 trust = !issetugid();
411 ld_bind_now = getenv(LD_ "BIND_NOW");
413 * If the process is tainted, then we un-set the dangerous environment
414 * variables. The process will be marked as tainted until setuid(2)
415 * is called. If any child process calls setuid(2) we do not want any
416 * future processes to honor the potentially un-safe variables.
419 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
420 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
421 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
422 unsetenv(LD_ "LOADFLTR") || unsetenv(LD_ "LIBRARY_PATH_RPATH")) {
423 _rtld_error("environment corrupt; aborting");
427 ld_debug = getenv(LD_ "DEBUG");
428 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
429 libmap_override = getenv(LD_ "LIBMAP");
430 ld_library_path = getenv(LD_ "LIBRARY_PATH");
431 ld_preload = getenv(LD_ "PRELOAD");
432 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
433 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
434 library_path_rpath = getenv(LD_ "LIBRARY_PATH_RPATH");
435 if (library_path_rpath != NULL) {
436 if (library_path_rpath[0] == 'y' ||
437 library_path_rpath[0] == 'Y' ||
438 library_path_rpath[0] == '1')
439 ld_library_path_rpath = true;
441 ld_library_path_rpath = false;
443 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
444 (ld_library_path != NULL) || (ld_preload != NULL) ||
445 (ld_elf_hints_path != NULL) || ld_loadfltr;
446 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
447 ld_utrace = getenv(LD_ "UTRACE");
449 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
450 ld_elf_hints_path = _PATH_ELF_HINTS;
452 if (ld_debug != NULL && *ld_debug != '\0')
454 dbg("%s is initialized, base address = %p", __progname,
455 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
456 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
457 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
459 dbg("initializing thread locks");
463 * Load the main program, or process its program header if it is
466 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
467 int fd = aux_info[AT_EXECFD]->a_un.a_val;
468 dbg("loading main program");
469 obj_main = map_object(fd, argv0, NULL);
471 if (obj_main == NULL)
473 max_stack_flags = obj->stack_flags;
474 } else { /* Main program already loaded. */
475 const Elf_Phdr *phdr;
479 dbg("processing main program's program header");
480 assert(aux_info[AT_PHDR] != NULL);
481 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
482 assert(aux_info[AT_PHNUM] != NULL);
483 phnum = aux_info[AT_PHNUM]->a_un.a_val;
484 assert(aux_info[AT_PHENT] != NULL);
485 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
486 assert(aux_info[AT_ENTRY] != NULL);
487 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
488 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
492 if (aux_info[AT_EXECPATH] != 0) {
494 char buf[MAXPATHLEN];
496 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
497 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
498 if (kexecpath[0] == '/')
499 obj_main->path = kexecpath;
500 else if (getcwd(buf, sizeof(buf)) == NULL ||
501 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
502 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
503 obj_main->path = xstrdup(argv0);
505 obj_main->path = xstrdup(buf);
507 dbg("No AT_EXECPATH");
508 obj_main->path = xstrdup(argv0);
510 dbg("obj_main path %s", obj_main->path);
511 obj_main->mainprog = true;
513 if (aux_info[AT_STACKPROT] != NULL &&
514 aux_info[AT_STACKPROT]->a_un.a_val != 0)
515 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
519 * Get the actual dynamic linker pathname from the executable if
520 * possible. (It should always be possible.) That ensures that
521 * gdb will find the right dynamic linker even if a non-standard
524 if (obj_main->interp != NULL &&
525 strcmp(obj_main->interp, obj_rtld.path) != 0) {
527 obj_rtld.path = xstrdup(obj_main->interp);
528 __progname = obj_rtld.path;
532 digest_dynamic(obj_main, 0);
533 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
534 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
535 obj_main->dynsymcount);
537 linkmap_add(obj_main);
538 linkmap_add(&obj_rtld);
540 /* Link the main program into the list of objects. */
541 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
545 /* Initialize a fake symbol for resolving undefined weak references. */
546 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
547 sym_zero.st_shndx = SHN_UNDEF;
548 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
551 libmap_disable = (bool)lm_init(libmap_override);
553 dbg("loading LD_PRELOAD libraries");
554 if (load_preload_objects() == -1)
556 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
558 dbg("loading needed objects");
559 if (load_needed_objects(obj_main, 0) == -1)
562 /* Make a list of all objects loaded at startup. */
563 last_interposer = obj_main;
564 TAILQ_FOREACH(obj, &obj_list, next) {
567 if (obj->z_interpose && obj != obj_main) {
568 objlist_put_after(&list_main, last_interposer, obj);
569 last_interposer = obj;
571 objlist_push_tail(&list_main, obj);
576 dbg("checking for required versions");
577 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
580 if (ld_tracing) { /* We're done */
581 trace_loaded_objects(obj_main);
585 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
586 dump_relocations(obj_main);
591 * Processing tls relocations requires having the tls offsets
592 * initialized. Prepare offsets before starting initial
593 * relocation processing.
595 dbg("initializing initial thread local storage offsets");
596 STAILQ_FOREACH(entry, &list_main, link) {
598 * Allocate all the initial objects out of the static TLS
599 * block even if they didn't ask for it.
601 allocate_tls_offset(entry->obj);
604 if (relocate_objects(obj_main,
605 ld_bind_now != NULL && *ld_bind_now != '\0',
606 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
609 dbg("doing copy relocations");
610 if (do_copy_relocations(obj_main) == -1)
613 dbg("enforcing main obj relro");
614 if (obj_enforce_relro(obj_main) == -1)
617 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
618 dump_relocations(obj_main);
623 * Setup TLS for main thread. This must be done after the
624 * relocations are processed, since tls initialization section
625 * might be the subject for relocations.
627 dbg("initializing initial thread local storage");
628 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
630 dbg("initializing key program variables");
631 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
632 set_program_var("environ", env);
633 set_program_var("__elf_aux_vector", aux);
635 /* Make a list of init functions to call. */
636 objlist_init(&initlist);
637 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
638 preload_tail, &initlist);
640 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
642 map_stacks_exec(NULL);
645 dbg("resolving ifuncs");
646 if (resolve_objects_ifunc(obj_main,
647 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
651 if (!obj_main->crt_no_init) {
653 * Make sure we don't call the main program's init and fini
654 * functions for binaries linked with old crt1 which calls
657 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
658 obj_main->preinit_array = obj_main->init_array =
659 obj_main->fini_array = (Elf_Addr)NULL;
662 wlock_acquire(rtld_bind_lock, &lockstate);
663 if (obj_main->crt_no_init)
665 objlist_call_init(&initlist, &lockstate);
666 _r_debug_postinit(&obj_main->linkmap);
667 objlist_clear(&initlist);
668 dbg("loading filtees");
669 TAILQ_FOREACH(obj, &obj_list, next) {
672 if (ld_loadfltr || obj->z_loadfltr)
673 load_filtees(obj, 0, &lockstate);
675 lock_release(rtld_bind_lock, &lockstate);
677 dbg("transferring control to program entry point = %p", obj_main->entry);
679 /* Return the exit procedure and the program entry point. */
680 *exit_proc = rtld_exit;
682 return (func_ptr_type) obj_main->entry;
686 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
691 ptr = (void *)make_function_pointer(def, obj);
692 target = call_ifunc_resolver(ptr);
693 return ((void *)target);
697 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
701 const Obj_Entry *defobj;
704 RtldLockState lockstate;
706 rlock_acquire(rtld_bind_lock, &lockstate);
707 if (sigsetjmp(lockstate.env, 0) != 0)
708 lock_upgrade(rtld_bind_lock, &lockstate);
710 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
712 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
714 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
715 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
719 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
720 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
722 target = (Elf_Addr)(defobj->relocbase + def->st_value);
724 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
725 defobj->strtab + def->st_name, basename(obj->path),
726 (void *)target, basename(defobj->path));
729 * Write the new contents for the jmpslot. Note that depending on
730 * architecture, the value which we need to return back to the
731 * lazy binding trampoline may or may not be the target
732 * address. The value returned from reloc_jmpslot() is the value
733 * that the trampoline needs.
735 target = reloc_jmpslot(where, target, defobj, obj, rel);
736 lock_release(rtld_bind_lock, &lockstate);
741 * Error reporting function. Use it like printf. If formats the message
742 * into a buffer, and sets things up so that the next call to dlerror()
743 * will return the message.
746 _rtld_error(const char *fmt, ...)
748 static char buf[512];
752 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
758 * Return a dynamically-allocated copy of the current error message, if any.
763 return error_message == NULL ? NULL : xstrdup(error_message);
767 * Restore the current error message from a copy which was previously saved
768 * by errmsg_save(). The copy is freed.
771 errmsg_restore(char *saved_msg)
773 if (saved_msg == NULL)
774 error_message = NULL;
776 _rtld_error("%s", saved_msg);
782 basename(const char *name)
784 const char *p = strrchr(name, '/');
785 return p != NULL ? p + 1 : name;
788 static struct utsname uts;
791 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
792 const char *subst, bool may_free)
794 char *p, *p1, *res, *resp;
795 int subst_len, kw_len, subst_count, old_len, new_len;
800 * First, count the number of the keyword occurences, to
801 * preallocate the final string.
803 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
810 * If the keyword is not found, just return.
812 * Return non-substituted string if resolution failed. We
813 * cannot do anything more reasonable, the failure mode of the
814 * caller is unresolved library anyway.
816 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
817 return (may_free ? real : xstrdup(real));
819 subst = obj->origin_path;
822 * There is indeed something to substitute. Calculate the
823 * length of the resulting string, and allocate it.
825 subst_len = strlen(subst);
826 old_len = strlen(real);
827 new_len = old_len + (subst_len - kw_len) * subst_count;
828 res = xmalloc(new_len + 1);
831 * Now, execute the substitution loop.
833 for (p = real, resp = res, *resp = '\0';;) {
836 /* Copy the prefix before keyword. */
837 memcpy(resp, p, p1 - p);
839 /* Keyword replacement. */
840 memcpy(resp, subst, subst_len);
848 /* Copy to the end of string and finish. */
856 origin_subst(Obj_Entry *obj, char *real)
858 char *res1, *res2, *res3, *res4;
860 if (obj == NULL || !trust)
861 return (xstrdup(real));
862 if (uts.sysname[0] == '\0') {
863 if (uname(&uts) != 0) {
864 _rtld_error("utsname failed: %d", errno);
868 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
869 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
870 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
871 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
878 const char *msg = dlerror();
882 rtld_fdputstr(STDERR_FILENO, msg);
883 rtld_fdputchar(STDERR_FILENO, '\n');
888 * Process a shared object's DYNAMIC section, and save the important
889 * information in its Obj_Entry structure.
892 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
893 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
896 Needed_Entry **needed_tail = &obj->needed;
897 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
898 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
899 const Elf_Hashelt *hashtab;
900 const Elf32_Word *hashval;
901 Elf32_Word bkt, nmaskwords;
903 int plttype = DT_REL;
909 obj->bind_now = false;
910 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
911 switch (dynp->d_tag) {
914 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
918 obj->relsize = dynp->d_un.d_val;
922 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
926 obj->pltrel = (const Elf_Rel *)
927 (obj->relocbase + dynp->d_un.d_ptr);
931 obj->pltrelsize = dynp->d_un.d_val;
935 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
939 obj->relasize = dynp->d_un.d_val;
943 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
947 plttype = dynp->d_un.d_val;
948 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
952 obj->symtab = (const Elf_Sym *)
953 (obj->relocbase + dynp->d_un.d_ptr);
957 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
961 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
965 obj->strsize = dynp->d_un.d_val;
969 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
974 obj->verneednum = dynp->d_un.d_val;
978 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
983 obj->verdefnum = dynp->d_un.d_val;
987 obj->versyms = (const Elf_Versym *)(obj->relocbase +
993 hashtab = (const Elf_Hashelt *)(obj->relocbase +
995 obj->nbuckets = hashtab[0];
996 obj->nchains = hashtab[1];
997 obj->buckets = hashtab + 2;
998 obj->chains = obj->buckets + obj->nbuckets;
999 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1000 obj->buckets != NULL;
1006 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1008 obj->nbuckets_gnu = hashtab[0];
1009 obj->symndx_gnu = hashtab[1];
1010 nmaskwords = hashtab[2];
1011 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1012 obj->maskwords_bm_gnu = nmaskwords - 1;
1013 obj->shift2_gnu = hashtab[3];
1014 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1015 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1016 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1018 /* Number of bitmask words is required to be power of 2 */
1019 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1020 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1026 Needed_Entry *nep = NEW(Needed_Entry);
1027 nep->name = dynp->d_un.d_val;
1032 needed_tail = &nep->next;
1038 Needed_Entry *nep = NEW(Needed_Entry);
1039 nep->name = dynp->d_un.d_val;
1043 *needed_filtees_tail = nep;
1044 needed_filtees_tail = &nep->next;
1050 Needed_Entry *nep = NEW(Needed_Entry);
1051 nep->name = dynp->d_un.d_val;
1055 *needed_aux_filtees_tail = nep;
1056 needed_aux_filtees_tail = &nep->next;
1061 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1065 obj->textrel = true;
1069 obj->symbolic = true;
1074 * We have to wait until later to process this, because we
1075 * might not have gotten the address of the string table yet.
1085 *dyn_runpath = dynp;
1089 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1092 case DT_PREINIT_ARRAY:
1093 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1096 case DT_PREINIT_ARRAYSZ:
1097 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1101 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1104 case DT_INIT_ARRAYSZ:
1105 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1109 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1113 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1116 case DT_FINI_ARRAYSZ:
1117 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1121 * Don't process DT_DEBUG on MIPS as the dynamic section
1122 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1128 dbg("Filling in DT_DEBUG entry");
1129 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1134 if (dynp->d_un.d_val & DF_ORIGIN)
1135 obj->z_origin = true;
1136 if (dynp->d_un.d_val & DF_SYMBOLIC)
1137 obj->symbolic = true;
1138 if (dynp->d_un.d_val & DF_TEXTREL)
1139 obj->textrel = true;
1140 if (dynp->d_un.d_val & DF_BIND_NOW)
1141 obj->bind_now = true;
1142 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1146 case DT_MIPS_LOCAL_GOTNO:
1147 obj->local_gotno = dynp->d_un.d_val;
1150 case DT_MIPS_SYMTABNO:
1151 obj->symtabno = dynp->d_un.d_val;
1154 case DT_MIPS_GOTSYM:
1155 obj->gotsym = dynp->d_un.d_val;
1158 case DT_MIPS_RLD_MAP:
1159 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1164 if (dynp->d_un.d_val & DF_1_NOOPEN)
1165 obj->z_noopen = true;
1166 if (dynp->d_un.d_val & DF_1_ORIGIN)
1167 obj->z_origin = true;
1168 if (dynp->d_un.d_val & DF_1_GLOBAL)
1169 obj->z_global = true;
1170 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1171 obj->bind_now = true;
1172 if (dynp->d_un.d_val & DF_1_NODELETE)
1173 obj->z_nodelete = true;
1174 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1175 obj->z_loadfltr = true;
1176 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1177 obj->z_interpose = true;
1178 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1179 obj->z_nodeflib = true;
1184 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1191 obj->traced = false;
1193 if (plttype == DT_RELA) {
1194 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1196 obj->pltrelasize = obj->pltrelsize;
1197 obj->pltrelsize = 0;
1200 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1201 if (obj->valid_hash_sysv)
1202 obj->dynsymcount = obj->nchains;
1203 else if (obj->valid_hash_gnu) {
1204 obj->dynsymcount = 0;
1205 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1206 if (obj->buckets_gnu[bkt] == 0)
1208 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1211 while ((*hashval++ & 1u) == 0);
1213 obj->dynsymcount += obj->symndx_gnu;
1218 obj_resolve_origin(Obj_Entry *obj)
1221 if (obj->origin_path != NULL)
1223 obj->origin_path = xmalloc(PATH_MAX);
1224 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1228 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1229 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1232 if (obj->z_origin && !obj_resolve_origin(obj))
1235 if (dyn_runpath != NULL) {
1236 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1237 obj->runpath = origin_subst(obj, obj->runpath);
1238 } else if (dyn_rpath != NULL) {
1239 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1240 obj->rpath = origin_subst(obj, obj->rpath);
1242 if (dyn_soname != NULL)
1243 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1247 digest_dynamic(Obj_Entry *obj, int early)
1249 const Elf_Dyn *dyn_rpath;
1250 const Elf_Dyn *dyn_soname;
1251 const Elf_Dyn *dyn_runpath;
1253 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1254 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1258 * Process a shared object's program header. This is used only for the
1259 * main program, when the kernel has already loaded the main program
1260 * into memory before calling the dynamic linker. It creates and
1261 * returns an Obj_Entry structure.
1264 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1267 const Elf_Phdr *phlimit = phdr + phnum;
1269 Elf_Addr note_start, note_end;
1273 for (ph = phdr; ph < phlimit; ph++) {
1274 if (ph->p_type != PT_PHDR)
1278 obj->phsize = ph->p_memsz;
1279 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1283 obj->stack_flags = PF_X | PF_R | PF_W;
1285 for (ph = phdr; ph < phlimit; ph++) {
1286 switch (ph->p_type) {
1289 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1293 if (nsegs == 0) { /* First load segment */
1294 obj->vaddrbase = trunc_page(ph->p_vaddr);
1295 obj->mapbase = obj->vaddrbase + obj->relocbase;
1296 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1298 } else { /* Last load segment */
1299 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1306 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1311 obj->tlssize = ph->p_memsz;
1312 obj->tlsalign = ph->p_align;
1313 obj->tlsinitsize = ph->p_filesz;
1314 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1318 obj->stack_flags = ph->p_flags;
1322 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1323 obj->relro_size = round_page(ph->p_memsz);
1327 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1328 note_end = note_start + ph->p_filesz;
1329 digest_notes(obj, note_start, note_end);
1334 _rtld_error("%s: too few PT_LOAD segments", path);
1343 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1345 const Elf_Note *note;
1346 const char *note_name;
1349 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1350 note = (const Elf_Note *)((const char *)(note + 1) +
1351 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1352 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1353 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1354 note->n_descsz != sizeof(int32_t))
1356 if (note->n_type != ABI_NOTETYPE &&
1357 note->n_type != CRT_NOINIT_NOTETYPE)
1359 note_name = (const char *)(note + 1);
1360 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1361 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1363 switch (note->n_type) {
1365 /* FreeBSD osrel note */
1366 p = (uintptr_t)(note + 1);
1367 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1368 obj->osrel = *(const int32_t *)(p);
1369 dbg("note osrel %d", obj->osrel);
1371 case CRT_NOINIT_NOTETYPE:
1372 /* FreeBSD 'crt does not call init' note */
1373 obj->crt_no_init = true;
1374 dbg("note crt_no_init");
1381 dlcheck(void *handle)
1385 TAILQ_FOREACH(obj, &obj_list, next) {
1386 if (obj == (Obj_Entry *) handle)
1390 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1391 _rtld_error("Invalid shared object handle %p", handle);
1398 * If the given object is already in the donelist, return true. Otherwise
1399 * add the object to the list and return false.
1402 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1406 for (i = 0; i < dlp->num_used; i++)
1407 if (dlp->objs[i] == obj)
1410 * Our donelist allocation should always be sufficient. But if
1411 * our threads locking isn't working properly, more shared objects
1412 * could have been loaded since we allocated the list. That should
1413 * never happen, but we'll handle it properly just in case it does.
1415 if (dlp->num_used < dlp->num_alloc)
1416 dlp->objs[dlp->num_used++] = obj;
1421 * Hash function for symbol table lookup. Don't even think about changing
1422 * this. It is specified by the System V ABI.
1425 elf_hash(const char *name)
1427 const unsigned char *p = (const unsigned char *) name;
1428 unsigned long h = 0;
1431 while (*p != '\0') {
1432 h = (h << 4) + *p++;
1433 if ((g = h & 0xf0000000) != 0)
1441 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1442 * unsigned in case it's implemented with a wider type.
1445 gnu_hash(const char *s)
1451 for (c = *s; c != '\0'; c = *++s)
1453 return (h & 0xffffffff);
1457 * Find the library with the given name, and return its full pathname.
1458 * The returned string is dynamically allocated. Generates an error
1459 * message and returns NULL if the library cannot be found.
1461 * If the second argument is non-NULL, then it refers to an already-
1462 * loaded shared object, whose library search path will be searched.
1464 * The search order is:
1465 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1466 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1468 * DT_RUNPATH in the referencing file
1469 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1471 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1473 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1476 find_library(const char *xname, const Obj_Entry *refobj)
1480 bool nodeflib, objgiven;
1482 objgiven = refobj != NULL;
1483 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1484 if (xname[0] != '/' && !trust) {
1485 _rtld_error("Absolute pathname required for shared object \"%s\"",
1489 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1490 __DECONST(char *, xname)));
1493 if (libmap_disable || !objgiven ||
1494 (name = lm_find(refobj->path, xname)) == NULL)
1495 name = (char *)xname;
1497 dbg(" Searching for \"%s\"", name);
1500 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1501 * back to pre-conforming behaviour if user requested so with
1502 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1505 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1506 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1508 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1509 (pathname = search_library_path(name, gethints(false))) != NULL ||
1510 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1513 nodeflib = objgiven ? refobj->z_nodeflib : false;
1515 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1516 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1517 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1518 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1520 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1521 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1522 (objgiven && !nodeflib &&
1523 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1527 if (objgiven && refobj->path != NULL) {
1528 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1529 name, basename(refobj->path));
1531 _rtld_error("Shared object \"%s\" not found", name);
1537 * Given a symbol number in a referencing object, find the corresponding
1538 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1539 * no definition was found. Returns a pointer to the Obj_Entry of the
1540 * defining object via the reference parameter DEFOBJ_OUT.
1543 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1544 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1545 RtldLockState *lockstate)
1549 const Obj_Entry *defobj;
1555 * If we have already found this symbol, get the information from
1558 if (symnum >= refobj->dynsymcount)
1559 return NULL; /* Bad object */
1560 if (cache != NULL && cache[symnum].sym != NULL) {
1561 *defobj_out = cache[symnum].obj;
1562 return cache[symnum].sym;
1565 ref = refobj->symtab + symnum;
1566 name = refobj->strtab + ref->st_name;
1571 * We don't have to do a full scale lookup if the symbol is local.
1572 * We know it will bind to the instance in this load module; to
1573 * which we already have a pointer (ie ref). By not doing a lookup,
1574 * we not only improve performance, but it also avoids unresolvable
1575 * symbols when local symbols are not in the hash table. This has
1576 * been seen with the ia64 toolchain.
1578 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1579 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1580 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1583 symlook_init(&req, name);
1585 req.ventry = fetch_ventry(refobj, symnum);
1586 req.lockstate = lockstate;
1587 res = symlook_default(&req, refobj);
1590 defobj = req.defobj_out;
1598 * If we found no definition and the reference is weak, treat the
1599 * symbol as having the value zero.
1601 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1607 *defobj_out = defobj;
1608 /* Record the information in the cache to avoid subsequent lookups. */
1609 if (cache != NULL) {
1610 cache[symnum].sym = def;
1611 cache[symnum].obj = defobj;
1614 if (refobj != &obj_rtld)
1615 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1621 * Return the search path from the ldconfig hints file, reading it if
1622 * necessary. If nostdlib is true, then the default search paths are
1623 * not added to result.
1625 * Returns NULL if there are problems with the hints file,
1626 * or if the search path there is empty.
1629 gethints(bool nostdlib)
1631 static char *hints, *filtered_path;
1632 static struct elfhints_hdr hdr;
1633 struct fill_search_info_args sargs, hargs;
1634 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1635 struct dl_serpath *SLPpath, *hintpath;
1637 struct stat hint_stat;
1638 unsigned int SLPndx, hintndx, fndx, fcount;
1644 /* First call, read the hints file */
1645 if (hints == NULL) {
1646 /* Keep from trying again in case the hints file is bad. */
1649 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1653 * Check of hdr.dirlistlen value against type limit
1654 * intends to pacify static analyzers. Further
1655 * paranoia leads to checks that dirlist is fully
1656 * contained in the file range.
1658 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1659 hdr.magic != ELFHINTS_MAGIC ||
1660 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1661 fstat(fd, &hint_stat) == -1) {
1668 if (dl + hdr.dirlist < dl)
1671 if (dl + hdr.dirlistlen < dl)
1673 dl += hdr.dirlistlen;
1674 if (dl > hint_stat.st_size)
1676 p = xmalloc(hdr.dirlistlen + 1);
1678 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1679 read(fd, p, hdr.dirlistlen + 1) !=
1680 (ssize_t)hdr.dirlistlen + 1 || p[hdr.dirlistlen] != '\0') {
1689 * If caller agreed to receive list which includes the default
1690 * paths, we are done. Otherwise, if we still did not
1691 * calculated filtered result, do it now.
1694 return (hints[0] != '\0' ? hints : NULL);
1695 if (filtered_path != NULL)
1699 * Obtain the list of all configured search paths, and the
1700 * list of the default paths.
1702 * First estimate the size of the results.
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(hints, fill_search_info, &hargs);
1717 SLPinfo = xmalloc(smeta.dls_size);
1718 hintinfo = xmalloc(hmeta.dls_size);
1721 * Next fetch both sets of paths.
1723 sargs.request = RTLD_DI_SERINFO;
1724 sargs.serinfo = SLPinfo;
1725 sargs.serpath = &SLPinfo->dls_serpath[0];
1726 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1728 hargs.request = RTLD_DI_SERINFO;
1729 hargs.serinfo = hintinfo;
1730 hargs.serpath = &hintinfo->dls_serpath[0];
1731 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1733 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1734 path_enumerate(hints, fill_search_info, &hargs);
1737 * Now calculate the difference between two sets, by excluding
1738 * standard paths from the full set.
1742 filtered_path = xmalloc(hdr.dirlistlen + 1);
1743 hintpath = &hintinfo->dls_serpath[0];
1744 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1746 SLPpath = &SLPinfo->dls_serpath[0];
1748 * Check each standard path against current.
1750 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1751 /* matched, skip the path */
1752 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1760 * Not matched against any standard path, add the path
1761 * to result. Separate consequtive paths with ':'.
1764 filtered_path[fndx] = ':';
1768 flen = strlen(hintpath->dls_name);
1769 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1772 filtered_path[fndx] = '\0';
1778 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1782 init_dag(Obj_Entry *root)
1784 const Needed_Entry *needed;
1785 const Objlist_Entry *elm;
1788 if (root->dag_inited)
1790 donelist_init(&donelist);
1792 /* Root object belongs to own DAG. */
1793 objlist_push_tail(&root->dldags, root);
1794 objlist_push_tail(&root->dagmembers, root);
1795 donelist_check(&donelist, root);
1798 * Add dependencies of root object to DAG in breadth order
1799 * by exploiting the fact that each new object get added
1800 * to the tail of the dagmembers list.
1802 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1803 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1804 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1806 objlist_push_tail(&needed->obj->dldags, root);
1807 objlist_push_tail(&root->dagmembers, needed->obj);
1810 root->dag_inited = true;
1814 globallist_curr(const Obj_Entry *obj)
1821 return (__DECONST(Obj_Entry *, obj));
1822 obj = TAILQ_PREV(obj, obj_entry_q, next);
1827 globallist_next(const Obj_Entry *obj)
1831 obj = TAILQ_NEXT(obj, next);
1835 return (__DECONST(Obj_Entry *, obj));
1840 process_z(Obj_Entry *root)
1842 const Objlist_Entry *elm;
1846 * Walk over object DAG and process every dependent object
1847 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
1848 * to grow their own DAG.
1850 * For DF_1_GLOBAL, DAG is required for symbol lookups in
1851 * symlook_global() to work.
1853 * For DF_1_NODELETE, the DAG should have its reference upped.
1855 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1859 if (obj->z_nodelete && !obj->ref_nodel) {
1860 dbg("obj %s -z nodelete", obj->path);
1863 obj->ref_nodel = true;
1865 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
1866 dbg("obj %s -z global", obj->path);
1867 objlist_push_tail(&list_global, obj);
1873 * Initialize the dynamic linker. The argument is the address at which
1874 * the dynamic linker has been mapped into memory. The primary task of
1875 * this function is to relocate the dynamic linker.
1878 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1880 Obj_Entry objtmp; /* Temporary rtld object */
1881 const Elf_Ehdr *ehdr;
1882 const Elf_Dyn *dyn_rpath;
1883 const Elf_Dyn *dyn_soname;
1884 const Elf_Dyn *dyn_runpath;
1886 #ifdef RTLD_INIT_PAGESIZES_EARLY
1887 /* The page size is required by the dynamic memory allocator. */
1888 init_pagesizes(aux_info);
1892 * Conjure up an Obj_Entry structure for the dynamic linker.
1894 * The "path" member can't be initialized yet because string constants
1895 * cannot yet be accessed. Below we will set it correctly.
1897 memset(&objtmp, 0, sizeof(objtmp));
1900 objtmp.mapbase = mapbase;
1902 objtmp.relocbase = mapbase;
1904 if (RTLD_IS_DYNAMIC()) {
1905 objtmp.dynamic = rtld_dynamic(&objtmp);
1906 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1907 assert(objtmp.needed == NULL);
1908 #if !defined(__mips__)
1909 /* MIPS has a bogus DT_TEXTREL. */
1910 assert(!objtmp.textrel);
1914 * Temporarily put the dynamic linker entry into the object list, so
1915 * that symbols can be found.
1918 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1920 ehdr = (Elf_Ehdr *)mapbase;
1921 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
1922 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
1924 /* Initialize the object list. */
1925 TAILQ_INIT(&obj_list);
1927 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1928 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1930 #ifndef RTLD_INIT_PAGESIZES_EARLY
1931 /* The page size is required by the dynamic memory allocator. */
1932 init_pagesizes(aux_info);
1935 if (aux_info[AT_OSRELDATE] != NULL)
1936 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1938 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1940 /* Replace the path with a dynamically allocated copy. */
1941 obj_rtld.path = xstrdup(PATH_RTLD);
1943 r_debug.r_brk = r_debug_state;
1944 r_debug.r_state = RT_CONSISTENT;
1948 * Retrieve the array of supported page sizes. The kernel provides the page
1949 * sizes in increasing order.
1952 init_pagesizes(Elf_Auxinfo **aux_info)
1954 static size_t psa[MAXPAGESIZES];
1958 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
1960 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
1961 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
1964 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
1967 /* As a fallback, retrieve the base page size. */
1968 size = sizeof(psa[0]);
1969 if (aux_info[AT_PAGESZ] != NULL) {
1970 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
1974 mib[1] = HW_PAGESIZE;
1978 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
1979 _rtld_error("sysctl for hw.pagesize(s) failed");
1985 npagesizes = size / sizeof(pagesizes[0]);
1986 /* Discard any invalid entries at the end of the array. */
1987 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
1992 * Add the init functions from a needed object list (and its recursive
1993 * needed objects) to "list". This is not used directly; it is a helper
1994 * function for initlist_add_objects(). The write lock must be held
1995 * when this function is called.
1998 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2000 /* Recursively process the successor needed objects. */
2001 if (needed->next != NULL)
2002 initlist_add_neededs(needed->next, list);
2004 /* Process the current needed object. */
2005 if (needed->obj != NULL)
2006 initlist_add_objects(needed->obj, needed->obj, list);
2010 * Scan all of the DAGs rooted in the range of objects from "obj" to
2011 * "tail" and add their init functions to "list". This recurses over
2012 * the DAGs and ensure the proper init ordering such that each object's
2013 * needed libraries are initialized before the object itself. At the
2014 * same time, this function adds the objects to the global finalization
2015 * list "list_fini" in the opposite order. The write lock must be
2016 * held when this function is called.
2019 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2023 if (obj->init_scanned || obj->init_done)
2025 obj->init_scanned = true;
2027 /* Recursively process the successor objects. */
2028 nobj = globallist_next(obj);
2029 if (nobj != NULL && obj != tail)
2030 initlist_add_objects(nobj, tail, list);
2032 /* Recursively process the needed objects. */
2033 if (obj->needed != NULL)
2034 initlist_add_neededs(obj->needed, list);
2035 if (obj->needed_filtees != NULL)
2036 initlist_add_neededs(obj->needed_filtees, list);
2037 if (obj->needed_aux_filtees != NULL)
2038 initlist_add_neededs(obj->needed_aux_filtees, list);
2040 /* Add the object to the init list. */
2041 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
2042 obj->init_array != (Elf_Addr)NULL)
2043 objlist_push_tail(list, obj);
2045 /* Add the object to the global fini list in the reverse order. */
2046 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2047 && !obj->on_fini_list) {
2048 objlist_push_head(&list_fini, obj);
2049 obj->on_fini_list = true;
2054 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2058 free_needed_filtees(Needed_Entry *n)
2060 Needed_Entry *needed, *needed1;
2062 for (needed = n; needed != NULL; needed = needed->next) {
2063 if (needed->obj != NULL) {
2064 dlclose(needed->obj);
2068 for (needed = n; needed != NULL; needed = needed1) {
2069 needed1 = needed->next;
2075 unload_filtees(Obj_Entry *obj)
2078 free_needed_filtees(obj->needed_filtees);
2079 obj->needed_filtees = NULL;
2080 free_needed_filtees(obj->needed_aux_filtees);
2081 obj->needed_aux_filtees = NULL;
2082 obj->filtees_loaded = false;
2086 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2087 RtldLockState *lockstate)
2090 for (; needed != NULL; needed = needed->next) {
2091 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2092 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2093 RTLD_LOCAL, lockstate);
2098 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2101 lock_restart_for_upgrade(lockstate);
2102 if (!obj->filtees_loaded) {
2103 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2104 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2105 obj->filtees_loaded = true;
2110 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2114 for (; needed != NULL; needed = needed->next) {
2115 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2116 flags & ~RTLD_LO_NOLOAD);
2117 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2124 * Given a shared object, traverse its list of needed objects, and load
2125 * each of them. Returns 0 on success. Generates an error message and
2126 * returns -1 on failure.
2129 load_needed_objects(Obj_Entry *first, int flags)
2133 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2136 if (process_needed(obj, obj->needed, flags) == -1)
2143 load_preload_objects(void)
2145 char *p = ld_preload;
2147 static const char delim[] = " \t:;";
2152 p += strspn(p, delim);
2153 while (*p != '\0') {
2154 size_t len = strcspn(p, delim);
2159 obj = load_object(p, -1, NULL, 0);
2161 return -1; /* XXX - cleanup */
2162 obj->z_interpose = true;
2165 p += strspn(p, delim);
2167 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2172 printable_path(const char *path)
2175 return (path == NULL ? "<unknown>" : path);
2179 * Load a shared object into memory, if it is not already loaded. The
2180 * object may be specified by name or by user-supplied file descriptor
2181 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2184 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2188 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2196 TAILQ_FOREACH(obj, &obj_list, next) {
2199 if (object_match_name(obj, name))
2203 path = find_library(name, refobj);
2210 * If we didn't find a match by pathname, or the name is not
2211 * supplied, open the file and check again by device and inode.
2212 * This avoids false mismatches caused by multiple links or ".."
2215 * To avoid a race, we open the file and use fstat() rather than
2220 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2221 _rtld_error("Cannot open \"%s\"", path);
2226 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2228 _rtld_error("Cannot dup fd");
2233 if (fstat(fd, &sb) == -1) {
2234 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2239 TAILQ_FOREACH(obj, &obj_list, next) {
2242 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2245 if (obj != NULL && name != NULL) {
2246 object_add_name(obj, name);
2251 if (flags & RTLD_LO_NOLOAD) {
2257 /* First use of this object, so we must map it in */
2258 obj = do_load_object(fd, name, path, &sb, flags);
2267 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2274 * but first, make sure that environment variables haven't been
2275 * used to circumvent the noexec flag on a filesystem.
2277 if (dangerous_ld_env) {
2278 if (fstatfs(fd, &fs) != 0) {
2279 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2282 if (fs.f_flags & MNT_NOEXEC) {
2283 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2287 dbg("loading \"%s\"", printable_path(path));
2288 obj = map_object(fd, printable_path(path), sbp);
2293 * If DT_SONAME is present in the object, digest_dynamic2 already
2294 * added it to the object names.
2297 object_add_name(obj, name);
2299 digest_dynamic(obj, 0);
2300 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2301 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2302 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2304 dbg("refusing to load non-loadable \"%s\"", obj->path);
2305 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2306 munmap(obj->mapbase, obj->mapsize);
2311 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2312 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2315 linkmap_add(obj); /* for GDB & dlinfo() */
2316 max_stack_flags |= obj->stack_flags;
2318 dbg(" %p .. %p: %s", obj->mapbase,
2319 obj->mapbase + obj->mapsize - 1, obj->path);
2321 dbg(" WARNING: %s has impure text", obj->path);
2322 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2329 obj_from_addr(const void *addr)
2333 TAILQ_FOREACH(obj, &obj_list, next) {
2336 if (addr < (void *) obj->mapbase)
2338 if (addr < (void *) (obj->mapbase + obj->mapsize))
2347 Elf_Addr *preinit_addr;
2350 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2351 if (preinit_addr == NULL)
2354 for (index = 0; index < obj_main->preinit_array_num; index++) {
2355 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2356 dbg("calling preinit function for %s at %p", obj_main->path,
2357 (void *)preinit_addr[index]);
2358 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2359 0, 0, obj_main->path);
2360 call_init_pointer(obj_main, preinit_addr[index]);
2366 * Call the finalization functions for each of the objects in "list"
2367 * belonging to the DAG of "root" and referenced once. If NULL "root"
2368 * is specified, every finalization function will be called regardless
2369 * of the reference count and the list elements won't be freed. All of
2370 * the objects are expected to have non-NULL fini functions.
2373 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2377 Elf_Addr *fini_addr;
2380 assert(root == NULL || root->refcount == 1);
2383 * Preserve the current error message since a fini function might
2384 * call into the dynamic linker and overwrite it.
2386 saved_msg = errmsg_save();
2388 STAILQ_FOREACH(elm, list, link) {
2389 if (root != NULL && (elm->obj->refcount != 1 ||
2390 objlist_find(&root->dagmembers, elm->obj) == NULL))
2392 /* Remove object from fini list to prevent recursive invocation. */
2393 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2395 * XXX: If a dlopen() call references an object while the
2396 * fini function is in progress, we might end up trying to
2397 * unload the referenced object in dlclose() or the object
2398 * won't be unloaded although its fini function has been
2401 lock_release(rtld_bind_lock, lockstate);
2404 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2405 * When this happens, DT_FINI_ARRAY is processed first.
2407 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2408 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2409 for (index = elm->obj->fini_array_num - 1; index >= 0;
2411 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2412 dbg("calling fini function for %s at %p",
2413 elm->obj->path, (void *)fini_addr[index]);
2414 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2415 (void *)fini_addr[index], 0, 0, elm->obj->path);
2416 call_initfini_pointer(elm->obj, fini_addr[index]);
2420 if (elm->obj->fini != (Elf_Addr)NULL) {
2421 dbg("calling fini function for %s at %p", elm->obj->path,
2422 (void *)elm->obj->fini);
2423 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2424 0, 0, elm->obj->path);
2425 call_initfini_pointer(elm->obj, elm->obj->fini);
2427 wlock_acquire(rtld_bind_lock, lockstate);
2428 /* No need to free anything if process is going down. */
2432 * We must restart the list traversal after every fini call
2433 * because a dlclose() call from the fini function or from
2434 * another thread might have modified the reference counts.
2438 } while (elm != NULL);
2439 errmsg_restore(saved_msg);
2443 * Call the initialization functions for each of the objects in
2444 * "list". All of the objects are expected to have non-NULL init
2448 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2453 Elf_Addr *init_addr;
2457 * Clean init_scanned flag so that objects can be rechecked and
2458 * possibly initialized earlier if any of vectors called below
2459 * cause the change by using dlopen.
2461 TAILQ_FOREACH(obj, &obj_list, next) {
2464 obj->init_scanned = false;
2468 * Preserve the current error message since an init function might
2469 * call into the dynamic linker and overwrite it.
2471 saved_msg = errmsg_save();
2472 STAILQ_FOREACH(elm, list, link) {
2473 if (elm->obj->init_done) /* Initialized early. */
2476 * Race: other thread might try to use this object before current
2477 * one completes the initialization. Not much can be done here
2478 * without better locking.
2480 elm->obj->init_done = true;
2481 lock_release(rtld_bind_lock, lockstate);
2484 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2485 * When this happens, DT_INIT is processed first.
2487 if (elm->obj->init != (Elf_Addr)NULL) {
2488 dbg("calling init function for %s at %p", elm->obj->path,
2489 (void *)elm->obj->init);
2490 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2491 0, 0, elm->obj->path);
2492 call_initfini_pointer(elm->obj, elm->obj->init);
2494 init_addr = (Elf_Addr *)elm->obj->init_array;
2495 if (init_addr != NULL) {
2496 for (index = 0; index < elm->obj->init_array_num; index++) {
2497 if (init_addr[index] != 0 && init_addr[index] != 1) {
2498 dbg("calling init function for %s at %p", elm->obj->path,
2499 (void *)init_addr[index]);
2500 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2501 (void *)init_addr[index], 0, 0, elm->obj->path);
2502 call_init_pointer(elm->obj, init_addr[index]);
2506 wlock_acquire(rtld_bind_lock, lockstate);
2508 errmsg_restore(saved_msg);
2512 objlist_clear(Objlist *list)
2516 while (!STAILQ_EMPTY(list)) {
2517 elm = STAILQ_FIRST(list);
2518 STAILQ_REMOVE_HEAD(list, link);
2523 static Objlist_Entry *
2524 objlist_find(Objlist *list, const Obj_Entry *obj)
2528 STAILQ_FOREACH(elm, list, link)
2529 if (elm->obj == obj)
2535 objlist_init(Objlist *list)
2541 objlist_push_head(Objlist *list, Obj_Entry *obj)
2545 elm = NEW(Objlist_Entry);
2547 STAILQ_INSERT_HEAD(list, elm, link);
2551 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2555 elm = NEW(Objlist_Entry);
2557 STAILQ_INSERT_TAIL(list, elm, link);
2561 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2563 Objlist_Entry *elm, *listelm;
2565 STAILQ_FOREACH(listelm, list, link) {
2566 if (listelm->obj == listobj)
2569 elm = NEW(Objlist_Entry);
2571 if (listelm != NULL)
2572 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2574 STAILQ_INSERT_TAIL(list, elm, link);
2578 objlist_remove(Objlist *list, Obj_Entry *obj)
2582 if ((elm = objlist_find(list, obj)) != NULL) {
2583 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2589 * Relocate dag rooted in the specified object.
2590 * Returns 0 on success, or -1 on failure.
2594 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2595 int flags, RtldLockState *lockstate)
2601 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2602 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2611 * Prepare for, or clean after, relocating an object marked with
2612 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2613 * segments are remapped read-write. After relocations are done, the
2614 * segment's permissions are returned back to the modes specified in
2615 * the phdrs. If any relocation happened, or always for wired
2616 * program, COW is triggered.
2619 reloc_textrel_prot(Obj_Entry *obj, bool before)
2626 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2628 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2630 base = obj->relocbase + trunc_page(ph->p_vaddr);
2631 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2632 trunc_page(ph->p_vaddr);
2633 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2634 if (mprotect(base, sz, prot) == -1) {
2635 _rtld_error("%s: Cannot write-%sable text segment: %s",
2636 obj->path, before ? "en" : "dis",
2637 rtld_strerror(errno));
2645 * Relocate single object.
2646 * Returns 0 on success, or -1 on failure.
2649 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2650 int flags, RtldLockState *lockstate)
2655 obj->relocated = true;
2657 dbg("relocating \"%s\"", obj->path);
2659 if (obj->symtab == NULL || obj->strtab == NULL ||
2660 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2661 _rtld_error("%s: Shared object has no run-time symbol table",
2666 /* There are relocations to the write-protected text segment. */
2667 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2670 /* Process the non-PLT non-IFUNC relocations. */
2671 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2674 /* Re-protected the text segment. */
2675 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2678 /* Set the special PLT or GOT entries. */
2681 /* Process the PLT relocations. */
2682 if (reloc_plt(obj) == -1)
2684 /* Relocate the jump slots if we are doing immediate binding. */
2685 if (obj->bind_now || bind_now)
2686 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2690 * Process the non-PLT IFUNC relocations. The relocations are
2691 * processed in two phases, because IFUNC resolvers may
2692 * reference other symbols, which must be readily processed
2693 * before resolvers are called.
2695 if (obj->non_plt_gnu_ifunc &&
2696 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2699 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2703 * Set up the magic number and version in the Obj_Entry. These
2704 * were checked in the crt1.o from the original ElfKit, so we
2705 * set them for backward compatibility.
2707 obj->magic = RTLD_MAGIC;
2708 obj->version = RTLD_VERSION;
2714 * Relocate newly-loaded shared objects. The argument is a pointer to
2715 * the Obj_Entry for the first such object. All objects from the first
2716 * to the end of the list of objects are relocated. Returns 0 on success,
2720 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2721 int flags, RtldLockState *lockstate)
2726 for (error = 0, obj = first; obj != NULL;
2727 obj = TAILQ_NEXT(obj, next)) {
2730 error = relocate_object(obj, bind_now, rtldobj, flags,
2739 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2740 * referencing STT_GNU_IFUNC symbols is postponed till the other
2741 * relocations are done. The indirect functions specified as
2742 * ifunc are allowed to call other symbols, so we need to have
2743 * objects relocated before asking for resolution from indirects.
2745 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2746 * instead of the usual lazy handling of PLT slots. It is
2747 * consistent with how GNU does it.
2750 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2751 RtldLockState *lockstate)
2753 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2755 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2756 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2762 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2763 RtldLockState *lockstate)
2767 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2770 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2777 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2778 RtldLockState *lockstate)
2782 STAILQ_FOREACH(elm, list, link) {
2783 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2791 * Cleanup procedure. It will be called (by the atexit mechanism) just
2792 * before the process exits.
2797 RtldLockState lockstate;
2799 wlock_acquire(rtld_bind_lock, &lockstate);
2801 objlist_call_fini(&list_fini, NULL, &lockstate);
2802 /* No need to remove the items from the list, since we are exiting. */
2803 if (!libmap_disable)
2805 lock_release(rtld_bind_lock, &lockstate);
2809 * Iterate over a search path, translate each element, and invoke the
2810 * callback on the result.
2813 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2819 path += strspn(path, ":;");
2820 while (*path != '\0') {
2824 len = strcspn(path, ":;");
2825 trans = lm_findn(NULL, path, len);
2827 res = callback(trans, strlen(trans), arg);
2829 res = callback(path, len, arg);
2835 path += strspn(path, ":;");
2841 struct try_library_args {
2849 try_library_path(const char *dir, size_t dirlen, void *param)
2851 struct try_library_args *arg;
2854 if (*dir == '/' || trust) {
2857 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2860 pathname = arg->buffer;
2861 strncpy(pathname, dir, dirlen);
2862 pathname[dirlen] = '/';
2863 strcpy(pathname + dirlen + 1, arg->name);
2865 dbg(" Trying \"%s\"", pathname);
2866 if (access(pathname, F_OK) == 0) { /* We found it */
2867 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2868 strcpy(pathname, arg->buffer);
2876 search_library_path(const char *name, const char *path)
2879 struct try_library_args arg;
2885 arg.namelen = strlen(name);
2886 arg.buffer = xmalloc(PATH_MAX);
2887 arg.buflen = PATH_MAX;
2889 p = path_enumerate(path, try_library_path, &arg);
2897 dlclose(void *handle)
2900 RtldLockState lockstate;
2902 wlock_acquire(rtld_bind_lock, &lockstate);
2903 root = dlcheck(handle);
2905 lock_release(rtld_bind_lock, &lockstate);
2908 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2911 /* Unreference the object and its dependencies. */
2912 root->dl_refcount--;
2914 if (root->refcount == 1) {
2916 * The object will be no longer referenced, so we must unload it.
2917 * First, call the fini functions.
2919 objlist_call_fini(&list_fini, root, &lockstate);
2923 /* Finish cleaning up the newly-unreferenced objects. */
2924 GDB_STATE(RT_DELETE,&root->linkmap);
2925 unload_object(root);
2926 GDB_STATE(RT_CONSISTENT,NULL);
2930 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2931 lock_release(rtld_bind_lock, &lockstate);
2938 char *msg = error_message;
2939 error_message = NULL;
2944 * This function is deprecated and has no effect.
2947 dllockinit(void *context,
2948 void *(*lock_create)(void *context),
2949 void (*rlock_acquire)(void *lock),
2950 void (*wlock_acquire)(void *lock),
2951 void (*lock_release)(void *lock),
2952 void (*lock_destroy)(void *lock),
2953 void (*context_destroy)(void *context))
2955 static void *cur_context;
2956 static void (*cur_context_destroy)(void *);
2958 /* Just destroy the context from the previous call, if necessary. */
2959 if (cur_context_destroy != NULL)
2960 cur_context_destroy(cur_context);
2961 cur_context = context;
2962 cur_context_destroy = context_destroy;
2966 dlopen(const char *name, int mode)
2969 return (rtld_dlopen(name, -1, mode));
2973 fdlopen(int fd, int mode)
2976 return (rtld_dlopen(NULL, fd, mode));
2980 rtld_dlopen(const char *name, int fd, int mode)
2982 RtldLockState lockstate;
2985 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2986 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2987 if (ld_tracing != NULL) {
2988 rlock_acquire(rtld_bind_lock, &lockstate);
2989 if (sigsetjmp(lockstate.env, 0) != 0)
2990 lock_upgrade(rtld_bind_lock, &lockstate);
2991 environ = (char **)*get_program_var_addr("environ", &lockstate);
2992 lock_release(rtld_bind_lock, &lockstate);
2994 lo_flags = RTLD_LO_DLOPEN;
2995 if (mode & RTLD_NODELETE)
2996 lo_flags |= RTLD_LO_NODELETE;
2997 if (mode & RTLD_NOLOAD)
2998 lo_flags |= RTLD_LO_NOLOAD;
2999 if (ld_tracing != NULL)
3000 lo_flags |= RTLD_LO_TRACE;
3002 return (dlopen_object(name, fd, obj_main, lo_flags,
3003 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3007 dlopen_cleanup(Obj_Entry *obj)
3012 if (obj->refcount == 0)
3017 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3018 int mode, RtldLockState *lockstate)
3020 Obj_Entry *old_obj_tail;
3023 RtldLockState mlockstate;
3026 objlist_init(&initlist);
3028 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3029 wlock_acquire(rtld_bind_lock, &mlockstate);
3030 lockstate = &mlockstate;
3032 GDB_STATE(RT_ADD,NULL);
3034 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3036 if (name == NULL && fd == -1) {
3040 obj = load_object(name, fd, refobj, lo_flags);
3045 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3046 objlist_push_tail(&list_global, obj);
3047 if (globallist_next(old_obj_tail) != NULL) {
3048 /* We loaded something new. */
3049 assert(globallist_next(old_obj_tail) == obj);
3050 result = load_needed_objects(obj,
3051 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3055 result = rtld_verify_versions(&obj->dagmembers);
3056 if (result != -1 && ld_tracing)
3058 if (result == -1 || relocate_object_dag(obj,
3059 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3060 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3062 dlopen_cleanup(obj);
3064 } else if (lo_flags & RTLD_LO_EARLY) {
3066 * Do not call the init functions for early loaded
3067 * filtees. The image is still not initialized enough
3070 * Our object is found by the global object list and
3071 * will be ordered among all init calls done right
3072 * before transferring control to main.
3075 /* Make list of init functions to call. */
3076 initlist_add_objects(obj, obj, &initlist);
3079 * Process all no_delete or global objects here, given
3080 * them own DAGs to prevent their dependencies from being
3081 * unloaded. This has to be done after we have loaded all
3082 * of the dependencies, so that we do not miss any.
3088 * Bump the reference counts for objects on this DAG. If
3089 * this is the first dlopen() call for the object that was
3090 * already loaded as a dependency, initialize the dag
3096 if ((lo_flags & RTLD_LO_TRACE) != 0)
3099 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3100 obj->z_nodelete) && !obj->ref_nodel) {
3101 dbg("obj %s nodelete", obj->path);
3103 obj->z_nodelete = obj->ref_nodel = true;
3107 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3109 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3111 if (!(lo_flags & RTLD_LO_EARLY)) {
3112 map_stacks_exec(lockstate);
3115 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3116 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3118 objlist_clear(&initlist);
3119 dlopen_cleanup(obj);
3120 if (lockstate == &mlockstate)
3121 lock_release(rtld_bind_lock, lockstate);
3125 if (!(lo_flags & RTLD_LO_EARLY)) {
3126 /* Call the init functions. */
3127 objlist_call_init(&initlist, lockstate);
3129 objlist_clear(&initlist);
3130 if (lockstate == &mlockstate)
3131 lock_release(rtld_bind_lock, lockstate);
3134 trace_loaded_objects(obj);
3135 if (lockstate == &mlockstate)
3136 lock_release(rtld_bind_lock, lockstate);
3141 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3145 const Obj_Entry *obj, *defobj;
3148 RtldLockState lockstate;
3157 symlook_init(&req, name);
3159 req.flags = flags | SYMLOOK_IN_PLT;
3160 req.lockstate = &lockstate;
3162 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3163 rlock_acquire(rtld_bind_lock, &lockstate);
3164 if (sigsetjmp(lockstate.env, 0) != 0)
3165 lock_upgrade(rtld_bind_lock, &lockstate);
3166 if (handle == NULL || handle == RTLD_NEXT ||
3167 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3169 if ((obj = obj_from_addr(retaddr)) == NULL) {
3170 _rtld_error("Cannot determine caller's shared object");
3171 lock_release(rtld_bind_lock, &lockstate);
3172 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3175 if (handle == NULL) { /* Just the caller's shared object. */
3176 res = symlook_obj(&req, obj);
3179 defobj = req.defobj_out;
3181 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3182 handle == RTLD_SELF) { /* ... caller included */
3183 if (handle == RTLD_NEXT)
3184 obj = globallist_next(obj);
3185 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3188 res = symlook_obj(&req, obj);
3191 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3193 defobj = req.defobj_out;
3194 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3200 * Search the dynamic linker itself, and possibly resolve the
3201 * symbol from there. This is how the application links to
3202 * dynamic linker services such as dlopen.
3204 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3205 res = symlook_obj(&req, &obj_rtld);
3208 defobj = req.defobj_out;
3212 assert(handle == RTLD_DEFAULT);
3213 res = symlook_default(&req, obj);
3215 defobj = req.defobj_out;
3220 if ((obj = dlcheck(handle)) == NULL) {
3221 lock_release(rtld_bind_lock, &lockstate);
3222 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3226 donelist_init(&donelist);
3227 if (obj->mainprog) {
3228 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3229 res = symlook_global(&req, &donelist);
3232 defobj = req.defobj_out;
3235 * Search the dynamic linker itself, and possibly resolve the
3236 * symbol from there. This is how the application links to
3237 * dynamic linker services such as dlopen.
3239 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3240 res = symlook_obj(&req, &obj_rtld);
3243 defobj = req.defobj_out;
3248 /* Search the whole DAG rooted at the given object. */
3249 res = symlook_list(&req, &obj->dagmembers, &donelist);
3252 defobj = req.defobj_out;
3258 lock_release(rtld_bind_lock, &lockstate);
3261 * The value required by the caller is derived from the value
3262 * of the symbol. For the ia64 architecture, we need to
3263 * construct a function descriptor which the caller can use to
3264 * call the function with the right 'gp' value. For other
3265 * architectures and for non-functions, the value is simply
3266 * the relocated value of the symbol.
3268 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3269 sym = make_function_pointer(def, defobj);
3270 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3271 sym = rtld_resolve_ifunc(defobj, def);
3272 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3274 return (__tls_get_addr(defobj->tlsindex, def->st_value));
3276 ti.ti_module = defobj->tlsindex;
3277 ti.ti_offset = def->st_value;
3278 sym = __tls_get_addr(&ti);
3281 sym = defobj->relocbase + def->st_value;
3282 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3286 _rtld_error("Undefined symbol \"%s\"", name);
3287 lock_release(rtld_bind_lock, &lockstate);
3288 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3293 dlsym(void *handle, const char *name)
3295 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3300 dlfunc(void *handle, const char *name)
3307 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3313 dlvsym(void *handle, const char *name, const char *version)
3317 ventry.name = version;
3319 ventry.hash = elf_hash(version);
3321 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3326 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3328 const Obj_Entry *obj;
3329 RtldLockState lockstate;
3331 rlock_acquire(rtld_bind_lock, &lockstate);
3332 obj = obj_from_addr(addr);
3334 _rtld_error("No shared object contains address");
3335 lock_release(rtld_bind_lock, &lockstate);
3338 rtld_fill_dl_phdr_info(obj, phdr_info);
3339 lock_release(rtld_bind_lock, &lockstate);
3344 dladdr(const void *addr, Dl_info *info)
3346 const Obj_Entry *obj;
3349 unsigned long symoffset;
3350 RtldLockState lockstate;
3352 rlock_acquire(rtld_bind_lock, &lockstate);
3353 obj = obj_from_addr(addr);
3355 _rtld_error("No shared object contains address");
3356 lock_release(rtld_bind_lock, &lockstate);
3359 info->dli_fname = obj->path;
3360 info->dli_fbase = obj->mapbase;
3361 info->dli_saddr = (void *)0;
3362 info->dli_sname = NULL;
3365 * Walk the symbol list looking for the symbol whose address is
3366 * closest to the address sent in.
3368 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3369 def = obj->symtab + symoffset;
3372 * For skip the symbol if st_shndx is either SHN_UNDEF or
3375 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3379 * If the symbol is greater than the specified address, or if it
3380 * is further away from addr than the current nearest symbol,
3383 symbol_addr = obj->relocbase + def->st_value;
3384 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3387 /* Update our idea of the nearest symbol. */
3388 info->dli_sname = obj->strtab + def->st_name;
3389 info->dli_saddr = symbol_addr;
3392 if (info->dli_saddr == addr)
3395 lock_release(rtld_bind_lock, &lockstate);
3400 dlinfo(void *handle, int request, void *p)
3402 const Obj_Entry *obj;
3403 RtldLockState lockstate;
3406 rlock_acquire(rtld_bind_lock, &lockstate);
3408 if (handle == NULL || handle == RTLD_SELF) {
3411 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3412 if ((obj = obj_from_addr(retaddr)) == NULL)
3413 _rtld_error("Cannot determine caller's shared object");
3415 obj = dlcheck(handle);
3418 lock_release(rtld_bind_lock, &lockstate);
3424 case RTLD_DI_LINKMAP:
3425 *((struct link_map const **)p) = &obj->linkmap;
3427 case RTLD_DI_ORIGIN:
3428 error = rtld_dirname(obj->path, p);
3431 case RTLD_DI_SERINFOSIZE:
3432 case RTLD_DI_SERINFO:
3433 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3437 _rtld_error("Invalid request %d passed to dlinfo()", request);
3441 lock_release(rtld_bind_lock, &lockstate);
3447 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3450 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3451 phdr_info->dlpi_name = obj->path;
3452 phdr_info->dlpi_phdr = obj->phdr;
3453 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3454 phdr_info->dlpi_tls_modid = obj->tlsindex;
3455 phdr_info->dlpi_tls_data = obj->tlsinit;
3456 phdr_info->dlpi_adds = obj_loads;
3457 phdr_info->dlpi_subs = obj_loads - obj_count;
3461 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3463 struct dl_phdr_info phdr_info;
3464 Obj_Entry *obj, marker;
3465 RtldLockState bind_lockstate, phdr_lockstate;
3468 bzero(&marker, sizeof(marker));
3469 marker.marker = true;
3472 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3473 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3474 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3475 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3476 rtld_fill_dl_phdr_info(obj, &phdr_info);
3477 lock_release(rtld_bind_lock, &bind_lockstate);
3479 error = callback(&phdr_info, sizeof phdr_info, param);
3481 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3482 obj = globallist_next(&marker);
3483 TAILQ_REMOVE(&obj_list, &marker, next);
3485 lock_release(rtld_bind_lock, &bind_lockstate);
3486 lock_release(rtld_phdr_lock, &phdr_lockstate);
3492 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3493 lock_release(rtld_bind_lock, &bind_lockstate);
3494 error = callback(&phdr_info, sizeof(phdr_info), param);
3496 lock_release(rtld_phdr_lock, &phdr_lockstate);
3501 fill_search_info(const char *dir, size_t dirlen, void *param)
3503 struct fill_search_info_args *arg;
3507 if (arg->request == RTLD_DI_SERINFOSIZE) {
3508 arg->serinfo->dls_cnt ++;
3509 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3511 struct dl_serpath *s_entry;
3513 s_entry = arg->serpath;
3514 s_entry->dls_name = arg->strspace;
3515 s_entry->dls_flags = arg->flags;
3517 strncpy(arg->strspace, dir, dirlen);
3518 arg->strspace[dirlen] = '\0';
3520 arg->strspace += dirlen + 1;
3528 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3530 struct dl_serinfo _info;
3531 struct fill_search_info_args args;
3533 args.request = RTLD_DI_SERINFOSIZE;
3534 args.serinfo = &_info;
3536 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3539 path_enumerate(obj->rpath, fill_search_info, &args);
3540 path_enumerate(ld_library_path, fill_search_info, &args);
3541 path_enumerate(obj->runpath, fill_search_info, &args);
3542 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3543 if (!obj->z_nodeflib)
3544 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3547 if (request == RTLD_DI_SERINFOSIZE) {
3548 info->dls_size = _info.dls_size;
3549 info->dls_cnt = _info.dls_cnt;
3553 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3554 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3558 args.request = RTLD_DI_SERINFO;
3559 args.serinfo = info;
3560 args.serpath = &info->dls_serpath[0];
3561 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3563 args.flags = LA_SER_RUNPATH;
3564 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3567 args.flags = LA_SER_LIBPATH;
3568 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3571 args.flags = LA_SER_RUNPATH;
3572 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3575 args.flags = LA_SER_CONFIG;
3576 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3580 args.flags = LA_SER_DEFAULT;
3581 if (!obj->z_nodeflib &&
3582 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3588 rtld_dirname(const char *path, char *bname)
3592 /* Empty or NULL string gets treated as "." */
3593 if (path == NULL || *path == '\0') {
3599 /* Strip trailing slashes */
3600 endp = path + strlen(path) - 1;
3601 while (endp > path && *endp == '/')
3604 /* Find the start of the dir */
3605 while (endp > path && *endp != '/')
3608 /* Either the dir is "/" or there are no slashes */
3610 bname[0] = *endp == '/' ? '/' : '.';
3616 } while (endp > path && *endp == '/');
3619 if (endp - path + 2 > PATH_MAX)
3621 _rtld_error("Filename is too long: %s", path);
3625 strncpy(bname, path, endp - path + 1);
3626 bname[endp - path + 1] = '\0';
3631 rtld_dirname_abs(const char *path, char *base)
3635 if (realpath(path, base) == NULL)
3637 dbg("%s -> %s", path, base);
3638 last = strrchr(base, '/');
3647 linkmap_add(Obj_Entry *obj)
3649 struct link_map *l = &obj->linkmap;
3650 struct link_map *prev;
3652 obj->linkmap.l_name = obj->path;
3653 obj->linkmap.l_addr = obj->mapbase;
3654 obj->linkmap.l_ld = obj->dynamic;
3656 /* GDB needs load offset on MIPS to use the symbols */
3657 obj->linkmap.l_offs = obj->relocbase;
3660 if (r_debug.r_map == NULL) {
3666 * Scan to the end of the list, but not past the entry for the
3667 * dynamic linker, which we want to keep at the very end.
3669 for (prev = r_debug.r_map;
3670 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3671 prev = prev->l_next)
3674 /* Link in the new entry. */
3676 l->l_next = prev->l_next;
3677 if (l->l_next != NULL)
3678 l->l_next->l_prev = l;
3683 linkmap_delete(Obj_Entry *obj)
3685 struct link_map *l = &obj->linkmap;
3687 if (l->l_prev == NULL) {
3688 if ((r_debug.r_map = l->l_next) != NULL)
3689 l->l_next->l_prev = NULL;
3693 if ((l->l_prev->l_next = l->l_next) != NULL)
3694 l->l_next->l_prev = l->l_prev;
3698 * Function for the debugger to set a breakpoint on to gain control.
3700 * The two parameters allow the debugger to easily find and determine
3701 * what the runtime loader is doing and to whom it is doing it.
3703 * When the loadhook trap is hit (r_debug_state, set at program
3704 * initialization), the arguments can be found on the stack:
3706 * +8 struct link_map *m
3707 * +4 struct r_debug *rd
3711 r_debug_state(struct r_debug* rd, struct link_map *m)
3714 * The following is a hack to force the compiler to emit calls to
3715 * this function, even when optimizing. If the function is empty,
3716 * the compiler is not obliged to emit any code for calls to it,
3717 * even when marked __noinline. However, gdb depends on those
3720 __compiler_membar();
3724 * A function called after init routines have completed. This can be used to
3725 * break before a program's entry routine is called, and can be used when
3726 * main is not available in the symbol table.
3729 _r_debug_postinit(struct link_map *m)
3732 /* See r_debug_state(). */
3733 __compiler_membar();
3737 * Get address of the pointer variable in the main program.
3738 * Prefer non-weak symbol over the weak one.
3740 static const void **
3741 get_program_var_addr(const char *name, RtldLockState *lockstate)
3746 symlook_init(&req, name);
3747 req.lockstate = lockstate;
3748 donelist_init(&donelist);
3749 if (symlook_global(&req, &donelist) != 0)
3751 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3752 return ((const void **)make_function_pointer(req.sym_out,
3754 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3755 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3757 return ((const void **)(req.defobj_out->relocbase +
3758 req.sym_out->st_value));
3762 * Set a pointer variable in the main program to the given value. This
3763 * is used to set key variables such as "environ" before any of the
3764 * init functions are called.
3767 set_program_var(const char *name, const void *value)
3771 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3772 dbg("\"%s\": *%p <-- %p", name, addr, value);
3778 * Search the global objects, including dependencies and main object,
3779 * for the given symbol.
3782 symlook_global(SymLook *req, DoneList *donelist)
3785 const Objlist_Entry *elm;
3788 symlook_init_from_req(&req1, req);
3790 /* Search all objects loaded at program start up. */
3791 if (req->defobj_out == NULL ||
3792 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3793 res = symlook_list(&req1, &list_main, donelist);
3794 if (res == 0 && (req->defobj_out == NULL ||
3795 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3796 req->sym_out = req1.sym_out;
3797 req->defobj_out = req1.defobj_out;
3798 assert(req->defobj_out != NULL);
3802 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3803 STAILQ_FOREACH(elm, &list_global, link) {
3804 if (req->defobj_out != NULL &&
3805 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3807 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3808 if (res == 0 && (req->defobj_out == NULL ||
3809 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3810 req->sym_out = req1.sym_out;
3811 req->defobj_out = req1.defobj_out;
3812 assert(req->defobj_out != NULL);
3816 return (req->sym_out != NULL ? 0 : ESRCH);
3820 * Given a symbol name in a referencing object, find the corresponding
3821 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3822 * no definition was found. Returns a pointer to the Obj_Entry of the
3823 * defining object via the reference parameter DEFOBJ_OUT.
3826 symlook_default(SymLook *req, const Obj_Entry *refobj)
3829 const Objlist_Entry *elm;
3833 donelist_init(&donelist);
3834 symlook_init_from_req(&req1, req);
3837 * Look first in the referencing object if linked symbolically,
3838 * and similarly handle protected symbols.
3840 res = symlook_obj(&req1, refobj);
3841 if (res == 0 && (refobj->symbolic ||
3842 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
3843 req->sym_out = req1.sym_out;
3844 req->defobj_out = req1.defobj_out;
3845 assert(req->defobj_out != NULL);
3847 if (refobj->symbolic || req->defobj_out != NULL)
3848 donelist_check(&donelist, refobj);
3850 symlook_global(req, &donelist);
3852 /* Search all dlopened DAGs containing the referencing object. */
3853 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3854 if (req->sym_out != NULL &&
3855 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3857 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3858 if (res == 0 && (req->sym_out == NULL ||
3859 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3860 req->sym_out = req1.sym_out;
3861 req->defobj_out = req1.defobj_out;
3862 assert(req->defobj_out != NULL);
3867 * Search the dynamic linker itself, and possibly resolve the
3868 * symbol from there. This is how the application links to
3869 * dynamic linker services such as dlopen.
3871 if (req->sym_out == NULL ||
3872 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3873 res = symlook_obj(&req1, &obj_rtld);
3875 req->sym_out = req1.sym_out;
3876 req->defobj_out = req1.defobj_out;
3877 assert(req->defobj_out != NULL);
3881 return (req->sym_out != NULL ? 0 : ESRCH);
3885 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3888 const Obj_Entry *defobj;
3889 const Objlist_Entry *elm;
3895 STAILQ_FOREACH(elm, objlist, link) {
3896 if (donelist_check(dlp, elm->obj))
3898 symlook_init_from_req(&req1, req);
3899 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3900 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3902 defobj = req1.defobj_out;
3903 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3910 req->defobj_out = defobj;
3917 * Search the chain of DAGS cointed to by the given Needed_Entry
3918 * for a symbol of the given name. Each DAG is scanned completely
3919 * before advancing to the next one. Returns a pointer to the symbol,
3920 * or NULL if no definition was found.
3923 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3926 const Needed_Entry *n;
3927 const Obj_Entry *defobj;
3933 symlook_init_from_req(&req1, req);
3934 for (n = needed; n != NULL; n = n->next) {
3935 if (n->obj == NULL ||
3936 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3938 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3940 defobj = req1.defobj_out;
3941 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3947 req->defobj_out = defobj;
3954 * Search the symbol table of a single shared object for a symbol of
3955 * the given name and version, if requested. Returns a pointer to the
3956 * symbol, or NULL if no definition was found. If the object is
3957 * filter, return filtered symbol from filtee.
3959 * The symbol's hash value is passed in for efficiency reasons; that
3960 * eliminates many recomputations of the hash value.
3963 symlook_obj(SymLook *req, const Obj_Entry *obj)
3967 int flags, res, mres;
3970 * If there is at least one valid hash at this point, we prefer to
3971 * use the faster GNU version if available.
3973 if (obj->valid_hash_gnu)
3974 mres = symlook_obj1_gnu(req, obj);
3975 else if (obj->valid_hash_sysv)
3976 mres = symlook_obj1_sysv(req, obj);
3981 if (obj->needed_filtees != NULL) {
3982 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3983 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3984 donelist_init(&donelist);
3985 symlook_init_from_req(&req1, req);
3986 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3988 req->sym_out = req1.sym_out;
3989 req->defobj_out = req1.defobj_out;
3993 if (obj->needed_aux_filtees != NULL) {
3994 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3995 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3996 donelist_init(&donelist);
3997 symlook_init_from_req(&req1, req);
3998 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4000 req->sym_out = req1.sym_out;
4001 req->defobj_out = req1.defobj_out;
4009 /* Symbol match routine common to both hash functions */
4011 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4012 const unsigned long symnum)
4015 const Elf_Sym *symp;
4018 symp = obj->symtab + symnum;
4019 strp = obj->strtab + symp->st_name;
4021 switch (ELF_ST_TYPE(symp->st_info)) {
4027 if (symp->st_value == 0)
4031 if (symp->st_shndx != SHN_UNDEF)
4034 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4035 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4042 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4045 if (req->ventry == NULL) {
4046 if (obj->versyms != NULL) {
4047 verndx = VER_NDX(obj->versyms[symnum]);
4048 if (verndx > obj->vernum) {
4050 "%s: symbol %s references wrong version %d",
4051 obj->path, obj->strtab + symnum, verndx);
4055 * If we are not called from dlsym (i.e. this
4056 * is a normal relocation from unversioned
4057 * binary), accept the symbol immediately if
4058 * it happens to have first version after this
4059 * shared object became versioned. Otherwise,
4060 * if symbol is versioned and not hidden,
4061 * remember it. If it is the only symbol with
4062 * this name exported by the shared object, it
4063 * will be returned as a match by the calling
4064 * function. If symbol is global (verndx < 2)
4065 * accept it unconditionally.
4067 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4068 verndx == VER_NDX_GIVEN) {
4069 result->sym_out = symp;
4072 else if (verndx >= VER_NDX_GIVEN) {
4073 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4075 if (result->vsymp == NULL)
4076 result->vsymp = symp;
4082 result->sym_out = symp;
4085 if (obj->versyms == NULL) {
4086 if (object_match_name(obj, req->ventry->name)) {
4087 _rtld_error("%s: object %s should provide version %s "
4088 "for symbol %s", obj_rtld.path, obj->path,
4089 req->ventry->name, obj->strtab + symnum);
4093 verndx = VER_NDX(obj->versyms[symnum]);
4094 if (verndx > obj->vernum) {
4095 _rtld_error("%s: symbol %s references wrong version %d",
4096 obj->path, obj->strtab + symnum, verndx);
4099 if (obj->vertab[verndx].hash != req->ventry->hash ||
4100 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4102 * Version does not match. Look if this is a
4103 * global symbol and if it is not hidden. If
4104 * global symbol (verndx < 2) is available,
4105 * use it. Do not return symbol if we are
4106 * called by dlvsym, because dlvsym looks for
4107 * a specific version and default one is not
4108 * what dlvsym wants.
4110 if ((req->flags & SYMLOOK_DLSYM) ||
4111 (verndx >= VER_NDX_GIVEN) ||
4112 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4116 result->sym_out = symp;
4121 * Search for symbol using SysV hash function.
4122 * obj->buckets is known not to be NULL at this point; the test for this was
4123 * performed with the obj->valid_hash_sysv assignment.
4126 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4128 unsigned long symnum;
4129 Sym_Match_Result matchres;
4131 matchres.sym_out = NULL;
4132 matchres.vsymp = NULL;
4133 matchres.vcount = 0;
4135 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4136 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4137 if (symnum >= obj->nchains)
4138 return (ESRCH); /* Bad object */
4140 if (matched_symbol(req, obj, &matchres, symnum)) {
4141 req->sym_out = matchres.sym_out;
4142 req->defobj_out = obj;
4146 if (matchres.vcount == 1) {
4147 req->sym_out = matchres.vsymp;
4148 req->defobj_out = obj;
4154 /* Search for symbol using GNU hash function */
4156 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4158 Elf_Addr bloom_word;
4159 const Elf32_Word *hashval;
4161 Sym_Match_Result matchres;
4162 unsigned int h1, h2;
4163 unsigned long symnum;
4165 matchres.sym_out = NULL;
4166 matchres.vsymp = NULL;
4167 matchres.vcount = 0;
4169 /* Pick right bitmask word from Bloom filter array */
4170 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4171 obj->maskwords_bm_gnu];
4173 /* Calculate modulus word size of gnu hash and its derivative */
4174 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4175 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4177 /* Filter out the "definitely not in set" queries */
4178 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4181 /* Locate hash chain and corresponding value element*/
4182 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4185 hashval = &obj->chain_zero_gnu[bucket];
4187 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4188 symnum = hashval - obj->chain_zero_gnu;
4189 if (matched_symbol(req, obj, &matchres, symnum)) {
4190 req->sym_out = matchres.sym_out;
4191 req->defobj_out = obj;
4195 } while ((*hashval++ & 1) == 0);
4196 if (matchres.vcount == 1) {
4197 req->sym_out = matchres.vsymp;
4198 req->defobj_out = obj;
4205 trace_loaded_objects(Obj_Entry *obj)
4207 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4210 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4213 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4214 fmt1 = "\t%o => %p (%x)\n";
4216 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4217 fmt2 = "\t%o (%x)\n";
4219 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
4221 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4222 Needed_Entry *needed;
4228 if (list_containers && obj->needed != NULL)
4229 rtld_printf("%s:\n", obj->path);
4230 for (needed = obj->needed; needed; needed = needed->next) {
4231 if (needed->obj != NULL) {
4232 if (needed->obj->traced && !list_containers)
4234 needed->obj->traced = true;
4235 path = needed->obj->path;
4239 name = (char *)obj->strtab + needed->name;
4240 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4242 fmt = is_lib ? fmt1 : fmt2;
4243 while ((c = *fmt++) != '\0') {
4269 rtld_putstr(main_local);
4272 rtld_putstr(obj_main->path);
4279 rtld_printf("%d", sodp->sod_major);
4282 rtld_printf("%d", sodp->sod_minor);
4289 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4302 * Unload a dlopened object and its dependencies from memory and from
4303 * our data structures. It is assumed that the DAG rooted in the
4304 * object has already been unreferenced, and that the object has a
4305 * reference count of 0.
4308 unload_object(Obj_Entry *root)
4310 Obj_Entry *obj, *obj1;
4312 assert(root->refcount == 0);
4315 * Pass over the DAG removing unreferenced objects from
4316 * appropriate lists.
4318 unlink_object(root);
4320 /* Unmap all objects that are no longer referenced. */
4321 TAILQ_FOREACH_SAFE(obj, &obj_list, next, obj1) {
4322 if (obj->marker || obj->refcount != 0)
4324 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4325 obj->mapsize, 0, obj->path);
4326 dbg("unloading \"%s\"", obj->path);
4327 unload_filtees(root);
4328 munmap(obj->mapbase, obj->mapsize);
4329 linkmap_delete(obj);
4330 TAILQ_REMOVE(&obj_list, obj, next);
4337 unlink_object(Obj_Entry *root)
4341 if (root->refcount == 0) {
4342 /* Remove the object from the RTLD_GLOBAL list. */
4343 objlist_remove(&list_global, root);
4345 /* Remove the object from all objects' DAG lists. */
4346 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4347 objlist_remove(&elm->obj->dldags, root);
4348 if (elm->obj != root)
4349 unlink_object(elm->obj);
4355 ref_dag(Obj_Entry *root)
4359 assert(root->dag_inited);
4360 STAILQ_FOREACH(elm, &root->dagmembers, link)
4361 elm->obj->refcount++;
4365 unref_dag(Obj_Entry *root)
4369 assert(root->dag_inited);
4370 STAILQ_FOREACH(elm, &root->dagmembers, link)
4371 elm->obj->refcount--;
4375 * Common code for MD __tls_get_addr().
4377 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4379 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4381 Elf_Addr *newdtv, *dtv;
4382 RtldLockState lockstate;
4386 /* Check dtv generation in case new modules have arrived */
4387 if (dtv[0] != tls_dtv_generation) {
4388 wlock_acquire(rtld_bind_lock, &lockstate);
4389 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4391 if (to_copy > tls_max_index)
4392 to_copy = tls_max_index;
4393 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4394 newdtv[0] = tls_dtv_generation;
4395 newdtv[1] = tls_max_index;
4397 lock_release(rtld_bind_lock, &lockstate);
4398 dtv = *dtvp = newdtv;
4401 /* Dynamically allocate module TLS if necessary */
4402 if (dtv[index + 1] == 0) {
4403 /* Signal safe, wlock will block out signals. */
4404 wlock_acquire(rtld_bind_lock, &lockstate);
4405 if (!dtv[index + 1])
4406 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4407 lock_release(rtld_bind_lock, &lockstate);
4409 return ((void *)(dtv[index + 1] + offset));
4413 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4418 /* Check dtv generation in case new modules have arrived */
4419 if (__predict_true(dtv[0] == tls_dtv_generation &&
4420 dtv[index + 1] != 0))
4421 return ((void *)(dtv[index + 1] + offset));
4422 return (tls_get_addr_slow(dtvp, index, offset));
4425 #if defined(__arm__) || defined(__ia64__) || defined(__mips__) || defined(__powerpc__)
4428 * Allocate Static TLS using the Variant I method.
4431 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4440 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4443 assert(tcbsize >= TLS_TCB_SIZE);
4444 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4445 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4447 if (oldtcb != NULL) {
4448 memcpy(tls, oldtcb, tls_static_space);
4451 /* Adjust the DTV. */
4453 for (i = 0; i < dtv[1]; i++) {
4454 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4455 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4456 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4460 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4462 dtv[0] = tls_dtv_generation;
4463 dtv[1] = tls_max_index;
4465 for (obj = globallist_curr(objs); obj != NULL;
4466 obj = globallist_next(obj)) {
4467 if (obj->tlsoffset > 0) {
4468 addr = (Elf_Addr)tls + obj->tlsoffset;
4469 if (obj->tlsinitsize > 0)
4470 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4471 if (obj->tlssize > obj->tlsinitsize)
4472 memset((void*) (addr + obj->tlsinitsize), 0,
4473 obj->tlssize - obj->tlsinitsize);
4474 dtv[obj->tlsindex + 1] = addr;
4483 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4486 Elf_Addr tlsstart, tlsend;
4489 assert(tcbsize >= TLS_TCB_SIZE);
4491 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4492 tlsend = tlsstart + tls_static_space;
4494 dtv = *(Elf_Addr **)tlsstart;
4496 for (i = 0; i < dtvsize; i++) {
4497 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4498 free((void*)dtv[i+2]);
4507 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4510 * Allocate Static TLS using the Variant II method.
4513 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4516 size_t size, ralign;
4518 Elf_Addr *dtv, *olddtv;
4519 Elf_Addr segbase, oldsegbase, addr;
4523 if (tls_static_max_align > ralign)
4524 ralign = tls_static_max_align;
4525 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4527 assert(tcbsize >= 2*sizeof(Elf_Addr));
4528 tls = malloc_aligned(size, ralign);
4529 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4531 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4532 ((Elf_Addr*)segbase)[0] = segbase;
4533 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4535 dtv[0] = tls_dtv_generation;
4536 dtv[1] = tls_max_index;
4540 * Copy the static TLS block over whole.
4542 oldsegbase = (Elf_Addr) oldtls;
4543 memcpy((void *)(segbase - tls_static_space),
4544 (const void *)(oldsegbase - tls_static_space),
4548 * If any dynamic TLS blocks have been created tls_get_addr(),
4551 olddtv = ((Elf_Addr**)oldsegbase)[1];
4552 for (i = 0; i < olddtv[1]; i++) {
4553 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4554 dtv[i+2] = olddtv[i+2];
4560 * We assume that this block was the one we created with
4561 * allocate_initial_tls().
4563 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4565 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4566 if (obj->marker || obj->tlsoffset == 0)
4568 addr = segbase - obj->tlsoffset;
4569 memset((void*) (addr + obj->tlsinitsize),
4570 0, obj->tlssize - obj->tlsinitsize);
4572 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4573 dtv[obj->tlsindex + 1] = addr;
4577 return (void*) segbase;
4581 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4584 size_t size, ralign;
4586 Elf_Addr tlsstart, tlsend;
4589 * Figure out the size of the initial TLS block so that we can
4590 * find stuff which ___tls_get_addr() allocated dynamically.
4593 if (tls_static_max_align > ralign)
4594 ralign = tls_static_max_align;
4595 size = round(tls_static_space, ralign);
4597 dtv = ((Elf_Addr**)tls)[1];
4599 tlsend = (Elf_Addr) tls;
4600 tlsstart = tlsend - size;
4601 for (i = 0; i < dtvsize; i++) {
4602 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4603 free_aligned((void *)dtv[i + 2]);
4607 free_aligned((void *)tlsstart);
4614 * Allocate TLS block for module with given index.
4617 allocate_module_tls(int index)
4622 TAILQ_FOREACH(obj, &obj_list, next) {
4625 if (obj->tlsindex == index)
4629 _rtld_error("Can't find module with TLS index %d", index);
4633 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4634 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4635 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4641 allocate_tls_offset(Obj_Entry *obj)
4648 if (obj->tlssize == 0) {
4649 obj->tls_done = true;
4653 if (tls_last_offset == 0)
4654 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4656 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4657 obj->tlssize, obj->tlsalign);
4660 * If we have already fixed the size of the static TLS block, we
4661 * must stay within that size. When allocating the static TLS, we
4662 * leave a small amount of space spare to be used for dynamically
4663 * loading modules which use static TLS.
4665 if (tls_static_space != 0) {
4666 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4668 } else if (obj->tlsalign > tls_static_max_align) {
4669 tls_static_max_align = obj->tlsalign;
4672 tls_last_offset = obj->tlsoffset = off;
4673 tls_last_size = obj->tlssize;
4674 obj->tls_done = true;
4680 free_tls_offset(Obj_Entry *obj)
4684 * If we were the last thing to allocate out of the static TLS
4685 * block, we give our space back to the 'allocator'. This is a
4686 * simplistic workaround to allow libGL.so.1 to be loaded and
4687 * unloaded multiple times.
4689 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4690 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4691 tls_last_offset -= obj->tlssize;
4697 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4700 RtldLockState lockstate;
4702 wlock_acquire(rtld_bind_lock, &lockstate);
4703 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
4705 lock_release(rtld_bind_lock, &lockstate);
4710 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4712 RtldLockState lockstate;
4714 wlock_acquire(rtld_bind_lock, &lockstate);
4715 free_tls(tcb, tcbsize, tcbalign);
4716 lock_release(rtld_bind_lock, &lockstate);
4720 object_add_name(Obj_Entry *obj, const char *name)
4726 entry = malloc(sizeof(Name_Entry) + len);
4728 if (entry != NULL) {
4729 strcpy(entry->name, name);
4730 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4735 object_match_name(const Obj_Entry *obj, const char *name)
4739 STAILQ_FOREACH(entry, &obj->names, link) {
4740 if (strcmp(name, entry->name) == 0)
4747 locate_dependency(const Obj_Entry *obj, const char *name)
4749 const Objlist_Entry *entry;
4750 const Needed_Entry *needed;
4752 STAILQ_FOREACH(entry, &list_main, link) {
4753 if (object_match_name(entry->obj, name))
4757 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4758 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4759 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4761 * If there is DT_NEEDED for the name we are looking for,
4762 * we are all set. Note that object might not be found if
4763 * dependency was not loaded yet, so the function can
4764 * return NULL here. This is expected and handled
4765 * properly by the caller.
4767 return (needed->obj);
4770 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4776 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4777 const Elf_Vernaux *vna)
4779 const Elf_Verdef *vd;
4780 const char *vername;
4782 vername = refobj->strtab + vna->vna_name;
4783 vd = depobj->verdef;
4785 _rtld_error("%s: version %s required by %s not defined",
4786 depobj->path, vername, refobj->path);
4790 if (vd->vd_version != VER_DEF_CURRENT) {
4791 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4792 depobj->path, vd->vd_version);
4795 if (vna->vna_hash == vd->vd_hash) {
4796 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4797 ((char *)vd + vd->vd_aux);
4798 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4801 if (vd->vd_next == 0)
4803 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4805 if (vna->vna_flags & VER_FLG_WEAK)
4807 _rtld_error("%s: version %s required by %s not found",
4808 depobj->path, vername, refobj->path);
4813 rtld_verify_object_versions(Obj_Entry *obj)
4815 const Elf_Verneed *vn;
4816 const Elf_Verdef *vd;
4817 const Elf_Verdaux *vda;
4818 const Elf_Vernaux *vna;
4819 const Obj_Entry *depobj;
4820 int maxvernum, vernum;
4822 if (obj->ver_checked)
4824 obj->ver_checked = true;
4828 * Walk over defined and required version records and figure out
4829 * max index used by any of them. Do very basic sanity checking
4833 while (vn != NULL) {
4834 if (vn->vn_version != VER_NEED_CURRENT) {
4835 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4836 obj->path, vn->vn_version);
4839 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4841 vernum = VER_NEED_IDX(vna->vna_other);
4842 if (vernum > maxvernum)
4844 if (vna->vna_next == 0)
4846 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4848 if (vn->vn_next == 0)
4850 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4854 while (vd != NULL) {
4855 if (vd->vd_version != VER_DEF_CURRENT) {
4856 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4857 obj->path, vd->vd_version);
4860 vernum = VER_DEF_IDX(vd->vd_ndx);
4861 if (vernum > maxvernum)
4863 if (vd->vd_next == 0)
4865 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4872 * Store version information in array indexable by version index.
4873 * Verify that object version requirements are satisfied along the
4876 obj->vernum = maxvernum + 1;
4877 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4880 while (vd != NULL) {
4881 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4882 vernum = VER_DEF_IDX(vd->vd_ndx);
4883 assert(vernum <= maxvernum);
4884 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4885 obj->vertab[vernum].hash = vd->vd_hash;
4886 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4887 obj->vertab[vernum].file = NULL;
4888 obj->vertab[vernum].flags = 0;
4890 if (vd->vd_next == 0)
4892 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4896 while (vn != NULL) {
4897 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4900 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4902 if (check_object_provided_version(obj, depobj, vna))
4904 vernum = VER_NEED_IDX(vna->vna_other);
4905 assert(vernum <= maxvernum);
4906 obj->vertab[vernum].hash = vna->vna_hash;
4907 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4908 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4909 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4910 VER_INFO_HIDDEN : 0;
4911 if (vna->vna_next == 0)
4913 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4915 if (vn->vn_next == 0)
4917 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4923 rtld_verify_versions(const Objlist *objlist)
4925 Objlist_Entry *entry;
4929 STAILQ_FOREACH(entry, objlist, link) {
4931 * Skip dummy objects or objects that have their version requirements
4934 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4936 if (rtld_verify_object_versions(entry->obj) == -1) {
4938 if (ld_tracing == NULL)
4942 if (rc == 0 || ld_tracing != NULL)
4943 rc = rtld_verify_object_versions(&obj_rtld);
4948 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4953 vernum = VER_NDX(obj->versyms[symnum]);
4954 if (vernum >= obj->vernum) {
4955 _rtld_error("%s: symbol %s has wrong verneed value %d",
4956 obj->path, obj->strtab + symnum, vernum);
4957 } else if (obj->vertab[vernum].hash != 0) {
4958 return &obj->vertab[vernum];
4965 _rtld_get_stack_prot(void)
4968 return (stack_prot);
4972 _rtld_is_dlopened(void *arg)
4975 RtldLockState lockstate;
4978 rlock_acquire(rtld_bind_lock, &lockstate);
4981 obj = obj_from_addr(arg);
4983 _rtld_error("No shared object contains address");
4984 lock_release(rtld_bind_lock, &lockstate);
4987 res = obj->dlopened ? 1 : 0;
4988 lock_release(rtld_bind_lock, &lockstate);
4993 obj_enforce_relro(Obj_Entry *obj)
4996 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
4998 _rtld_error("%s: Cannot enforce relro protection: %s",
4999 obj->path, rtld_strerror(errno));
5006 map_stacks_exec(RtldLockState *lockstate)
5008 void (*thr_map_stacks_exec)(void);
5010 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5012 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5013 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5014 if (thr_map_stacks_exec != NULL) {
5015 stack_prot |= PROT_EXEC;
5016 thr_map_stacks_exec();
5021 symlook_init(SymLook *dst, const char *name)
5024 bzero(dst, sizeof(*dst));
5026 dst->hash = elf_hash(name);
5027 dst->hash_gnu = gnu_hash(name);
5031 symlook_init_from_req(SymLook *dst, const SymLook *src)
5034 dst->name = src->name;
5035 dst->hash = src->hash;
5036 dst->hash_gnu = src->hash_gnu;
5037 dst->ventry = src->ventry;
5038 dst->flags = src->flags;
5039 dst->defobj_out = NULL;
5040 dst->sym_out = NULL;
5041 dst->lockstate = src->lockstate;
5045 * Overrides for libc_pic-provided functions.
5049 __getosreldate(void)
5059 oid[1] = KERN_OSRELDATE;
5061 len = sizeof(osrel);
5062 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5063 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5075 void (*__cleanup)(void);
5076 int __isthreaded = 0;
5077 int _thread_autoinit_dummy_decl = 1;
5080 * No unresolved symbols for rtld.
5083 __pthread_cxa_finalize(struct dl_phdr_info *a)
5088 __stack_chk_fail(void)
5091 _rtld_error("stack overflow detected; terminated");
5094 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5100 _rtld_error("buffer overflow detected; terminated");
5105 rtld_strerror(int errnum)
5108 if (errnum < 0 || errnum >= sys_nerr)
5109 return ("Unknown error");
5110 return (sys_errlist[errnum]);