2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009, 2010, 2011 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 * Dynamic linker for ELF.
33 * John Polstra <jdp@polstra.com>.
37 #error "GCC is needed to compile this file"
40 #include <sys/param.h>
41 #include <sys/mount.h>
44 #include <sys/sysctl.h>
46 #include <sys/utsname.h>
47 #include <sys/ktrace.h>
63 #include "rtld_printf.h"
66 #define PATH_RTLD "/libexec/ld-elf.so.1"
68 #define PATH_RTLD "/libexec/ld-elf32.so.1"
72 typedef void (*func_ptr_type)();
73 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
76 * Function declarations.
78 static const char *basename(const char *);
79 static void die(void) __dead2;
80 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
82 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *);
83 static void digest_dynamic(Obj_Entry *, int);
84 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
85 static Obj_Entry *dlcheck(void *);
86 static Obj_Entry *dlopen_object(const char *name, Obj_Entry *refobj,
87 int lo_flags, int mode);
88 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
89 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
90 static bool donelist_check(DoneList *, const Obj_Entry *);
91 static void errmsg_restore(char *);
92 static char *errmsg_save(void);
93 static void *fill_search_info(const char *, size_t, void *);
94 static char *find_library(const char *, const Obj_Entry *);
95 static const char *gethints(void);
96 static void init_dag(Obj_Entry *);
97 static void init_rtld(caddr_t, Elf_Auxinfo **);
98 static void initlist_add_neededs(Needed_Entry *, Objlist *);
99 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
100 static void linkmap_add(Obj_Entry *);
101 static void linkmap_delete(Obj_Entry *);
102 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
103 static void unload_filtees(Obj_Entry *);
104 static int load_needed_objects(Obj_Entry *, int);
105 static int load_preload_objects(void);
106 static Obj_Entry *load_object(const char *, const Obj_Entry *, int);
107 static void map_stacks_exec(RtldLockState *);
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_remove(Objlist *, Obj_Entry *);
117 static void *path_enumerate(const char *, path_enum_proc, void *);
118 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, RtldLockState *);
119 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
120 RtldLockState *lockstate);
121 static int rtld_dirname(const char *, char *);
122 static int rtld_dirname_abs(const char *, char *);
123 static void rtld_exit(void);
124 static char *search_library_path(const char *, const char *);
125 static const void **get_program_var_addr(const char *, RtldLockState *);
126 static void set_program_var(const char *, const void *);
127 static int symlook_default(SymLook *, const Obj_Entry *refobj);
128 static int symlook_global(SymLook *, DoneList *);
129 static void symlook_init_from_req(SymLook *, const SymLook *);
130 static int symlook_list(SymLook *, const Objlist *, DoneList *);
131 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
132 static int symlook_obj1(SymLook *, const Obj_Entry *);
133 static void trace_loaded_objects(Obj_Entry *);
134 static void unlink_object(Obj_Entry *);
135 static void unload_object(Obj_Entry *);
136 static void unref_dag(Obj_Entry *);
137 static void ref_dag(Obj_Entry *);
138 static int origin_subst_one(char **, const char *, const char *,
139 const char *, char *);
140 static char *origin_subst(const char *, const char *);
141 static int rtld_verify_versions(const Objlist *);
142 static int rtld_verify_object_versions(Obj_Entry *);
143 static void object_add_name(Obj_Entry *, const char *);
144 static int object_match_name(const Obj_Entry *, const char *);
145 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
146 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
147 struct dl_phdr_info *phdr_info);
149 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
154 static char *error_message; /* Message for dlerror(), or NULL */
155 struct r_debug r_debug; /* for GDB; */
156 static bool libmap_disable; /* Disable libmap */
157 static bool ld_loadfltr; /* Immediate filters processing */
158 static char *libmap_override; /* Maps to use in addition to libmap.conf */
159 static bool trust; /* False for setuid and setgid programs */
160 static bool dangerous_ld_env; /* True if environment variables have been
161 used to affect the libraries loaded */
162 static char *ld_bind_now; /* Environment variable for immediate binding */
163 static char *ld_debug; /* Environment variable for debugging */
164 static char *ld_library_path; /* Environment variable for search path */
165 static char *ld_preload; /* Environment variable for libraries to
167 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
168 static char *ld_tracing; /* Called from ldd to print libs */
169 static char *ld_utrace; /* Use utrace() to log events. */
170 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
171 static Obj_Entry **obj_tail; /* Link field of last object in list */
172 static Obj_Entry *obj_main; /* The main program shared object */
173 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
174 static unsigned int obj_count; /* Number of objects in obj_list */
175 static unsigned int obj_loads; /* Number of objects in obj_list */
177 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
178 STAILQ_HEAD_INITIALIZER(list_global);
179 static Objlist list_main = /* Objects loaded at program startup */
180 STAILQ_HEAD_INITIALIZER(list_main);
181 static Objlist list_fini = /* Objects needing fini() calls */
182 STAILQ_HEAD_INITIALIZER(list_fini);
184 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
186 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
188 extern Elf_Dyn _DYNAMIC;
189 #pragma weak _DYNAMIC
190 #ifndef RTLD_IS_DYNAMIC
191 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
194 int osreldate, pagesize;
196 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
197 static int max_stack_flags;
200 * Global declarations normally provided by crt1. The dynamic linker is
201 * not built with crt1, so we have to provide them ourselves.
207 * Globals to control TLS allocation.
209 size_t tls_last_offset; /* Static TLS offset of last module */
210 size_t tls_last_size; /* Static TLS size of last module */
211 size_t tls_static_space; /* Static TLS space allocated */
212 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
213 int tls_max_index = 1; /* Largest module index allocated */
216 * Fill in a DoneList with an allocation large enough to hold all of
217 * the currently-loaded objects. Keep this as a macro since it calls
218 * alloca and we want that to occur within the scope of the caller.
220 #define donelist_init(dlp) \
221 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
222 assert((dlp)->objs != NULL), \
223 (dlp)->num_alloc = obj_count, \
226 #define UTRACE_DLOPEN_START 1
227 #define UTRACE_DLOPEN_STOP 2
228 #define UTRACE_DLCLOSE_START 3
229 #define UTRACE_DLCLOSE_STOP 4
230 #define UTRACE_LOAD_OBJECT 5
231 #define UTRACE_UNLOAD_OBJECT 6
232 #define UTRACE_ADD_RUNDEP 7
233 #define UTRACE_PRELOAD_FINISHED 8
234 #define UTRACE_INIT_CALL 9
235 #define UTRACE_FINI_CALL 10
238 char sig[4]; /* 'RTLD' */
241 void *mapbase; /* Used for 'parent' and 'init/fini' */
243 int refcnt; /* Used for 'mode' */
244 char name[MAXPATHLEN];
247 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
248 if (ld_utrace != NULL) \
249 ld_utrace_log(e, h, mb, ms, r, n); \
253 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
254 int refcnt, const char *name)
256 struct utrace_rtld ut;
264 ut.mapbase = mapbase;
265 ut.mapsize = mapsize;
267 bzero(ut.name, sizeof(ut.name));
269 strlcpy(ut.name, name, sizeof(ut.name));
270 utrace(&ut, sizeof(ut));
274 * Main entry point for dynamic linking. The first argument is the
275 * stack pointer. The stack is expected to be laid out as described
276 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
277 * Specifically, the stack pointer points to a word containing
278 * ARGC. Following that in the stack is a null-terminated sequence
279 * of pointers to argument strings. Then comes a null-terminated
280 * sequence of pointers to environment strings. Finally, there is a
281 * sequence of "auxiliary vector" entries.
283 * The second argument points to a place to store the dynamic linker's
284 * exit procedure pointer and the third to a place to store the main
287 * The return value is the main program's entry point.
290 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
292 Elf_Auxinfo *aux_info[AT_COUNT];
300 Objlist_Entry *entry;
302 Obj_Entry **preload_tail;
304 RtldLockState lockstate;
307 * On entry, the dynamic linker itself has not been relocated yet.
308 * Be very careful not to reference any global data until after
309 * init_rtld has returned. It is OK to reference file-scope statics
310 * and string constants, and to call static and global functions.
313 /* Find the auxiliary vector on the stack. */
316 sp += argc + 1; /* Skip over arguments and NULL terminator */
318 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
320 aux = (Elf_Auxinfo *) sp;
322 /* Digest the auxiliary vector. */
323 for (i = 0; i < AT_COUNT; i++)
325 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
326 if (auxp->a_type < AT_COUNT)
327 aux_info[auxp->a_type] = auxp;
330 /* Initialize and relocate ourselves. */
331 assert(aux_info[AT_BASE] != NULL);
332 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
334 __progname = obj_rtld.path;
335 argv0 = argv[0] != NULL ? argv[0] : "(null)";
338 trust = !issetugid();
340 ld_bind_now = getenv(LD_ "BIND_NOW");
342 * If the process is tainted, then we un-set the dangerous environment
343 * variables. The process will be marked as tainted until setuid(2)
344 * is called. If any child process calls setuid(2) we do not want any
345 * future processes to honor the potentially un-safe variables.
348 if (unsetenv(LD_ "PRELOAD") || unsetenv(LD_ "LIBMAP") ||
349 unsetenv(LD_ "LIBRARY_PATH") || unsetenv(LD_ "LIBMAP_DISABLE") ||
350 unsetenv(LD_ "DEBUG") || unsetenv(LD_ "ELF_HINTS_PATH") ||
351 unsetenv(LD_ "LOADFLTR")) {
352 _rtld_error("environment corrupt; aborting");
356 ld_debug = getenv(LD_ "DEBUG");
357 libmap_disable = getenv(LD_ "LIBMAP_DISABLE") != NULL;
358 libmap_override = getenv(LD_ "LIBMAP");
359 ld_library_path = getenv(LD_ "LIBRARY_PATH");
360 ld_preload = getenv(LD_ "PRELOAD");
361 ld_elf_hints_path = getenv(LD_ "ELF_HINTS_PATH");
362 ld_loadfltr = getenv(LD_ "LOADFLTR") != NULL;
363 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
364 (ld_library_path != NULL) || (ld_preload != NULL) ||
365 (ld_elf_hints_path != NULL) || ld_loadfltr;
366 ld_tracing = getenv(LD_ "TRACE_LOADED_OBJECTS");
367 ld_utrace = getenv(LD_ "UTRACE");
369 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
370 ld_elf_hints_path = _PATH_ELF_HINTS;
372 if (ld_debug != NULL && *ld_debug != '\0')
374 dbg("%s is initialized, base address = %p", __progname,
375 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
376 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
377 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
379 dbg("initializing thread locks");
383 * Load the main program, or process its program header if it is
386 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
387 int fd = aux_info[AT_EXECFD]->a_un.a_val;
388 dbg("loading main program");
389 obj_main = map_object(fd, argv0, NULL);
391 if (obj_main == NULL)
393 max_stack_flags = obj->stack_flags;
394 } else { /* Main program already loaded. */
395 const Elf_Phdr *phdr;
399 dbg("processing main program's program header");
400 assert(aux_info[AT_PHDR] != NULL);
401 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
402 assert(aux_info[AT_PHNUM] != NULL);
403 phnum = aux_info[AT_PHNUM]->a_un.a_val;
404 assert(aux_info[AT_PHENT] != NULL);
405 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
406 assert(aux_info[AT_ENTRY] != NULL);
407 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
408 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
412 if (aux_info[AT_EXECPATH] != 0) {
414 char buf[MAXPATHLEN];
416 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
417 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
418 if (kexecpath[0] == '/')
419 obj_main->path = kexecpath;
420 else if (getcwd(buf, sizeof(buf)) == NULL ||
421 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
422 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
423 obj_main->path = xstrdup(argv0);
425 obj_main->path = xstrdup(buf);
427 dbg("No AT_EXECPATH");
428 obj_main->path = xstrdup(argv0);
430 dbg("obj_main path %s", obj_main->path);
431 obj_main->mainprog = true;
433 if (aux_info[AT_STACKPROT] != NULL &&
434 aux_info[AT_STACKPROT]->a_un.a_val != 0)
435 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
438 * Get the actual dynamic linker pathname from the executable if
439 * possible. (It should always be possible.) That ensures that
440 * gdb will find the right dynamic linker even if a non-standard
443 if (obj_main->interp != NULL &&
444 strcmp(obj_main->interp, obj_rtld.path) != 0) {
446 obj_rtld.path = xstrdup(obj_main->interp);
447 __progname = obj_rtld.path;
450 digest_dynamic(obj_main, 0);
452 linkmap_add(obj_main);
453 linkmap_add(&obj_rtld);
455 /* Link the main program into the list of objects. */
456 *obj_tail = obj_main;
457 obj_tail = &obj_main->next;
460 /* Make sure we don't call the main program's init and fini functions. */
461 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
463 /* Initialize a fake symbol for resolving undefined weak references. */
464 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
465 sym_zero.st_shndx = SHN_UNDEF;
466 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
469 libmap_disable = (bool)lm_init(libmap_override);
471 dbg("loading LD_PRELOAD libraries");
472 if (load_preload_objects() == -1)
474 preload_tail = obj_tail;
476 dbg("loading needed objects");
477 if (load_needed_objects(obj_main, 0) == -1)
480 /* Make a list of all objects loaded at startup. */
481 for (obj = obj_list; obj != NULL; obj = obj->next) {
482 objlist_push_tail(&list_main, obj);
486 dbg("checking for required versions");
487 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
490 if (ld_tracing) { /* We're done */
491 trace_loaded_objects(obj_main);
495 if (getenv(LD_ "DUMP_REL_PRE") != NULL) {
496 dump_relocations(obj_main);
501 * Processing tls relocations requires having the tls offsets
502 * initialized. Prepare offsets before starting initial
503 * relocation processing.
505 dbg("initializing initial thread local storage offsets");
506 STAILQ_FOREACH(entry, &list_main, link) {
508 * Allocate all the initial objects out of the static TLS
509 * block even if they didn't ask for it.
511 allocate_tls_offset(entry->obj);
514 if (relocate_objects(obj_main,
515 ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, NULL) == -1)
518 if (resolve_objects_ifunc(obj_main,
519 ld_bind_now != NULL && *ld_bind_now != '\0', NULL) == -1)
522 dbg("doing copy relocations");
523 if (do_copy_relocations(obj_main) == -1)
526 if (getenv(LD_ "DUMP_REL_POST") != NULL) {
527 dump_relocations(obj_main);
532 * Setup TLS for main thread. This must be done after the
533 * relocations are processed, since tls initialization section
534 * might be the subject for relocations.
536 dbg("initializing initial thread local storage");
537 allocate_initial_tls(obj_list);
539 dbg("initializing key program variables");
540 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
541 set_program_var("environ", env);
542 set_program_var("__elf_aux_vector", aux);
544 /* Make a list of init functions to call. */
545 objlist_init(&initlist);
546 initlist_add_objects(obj_list, preload_tail, &initlist);
548 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
550 map_stacks_exec(NULL);
552 wlock_acquire(rtld_bind_lock, &lockstate);
553 objlist_call_init(&initlist, &lockstate);
554 objlist_clear(&initlist);
555 dbg("loading filtees");
556 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
557 if (ld_loadfltr || obj->z_loadfltr)
558 load_filtees(obj, 0, &lockstate);
560 lock_release(rtld_bind_lock, &lockstate);
562 dbg("transferring control to program entry point = %p", obj_main->entry);
564 /* Return the exit procedure and the program entry point. */
565 *exit_proc = rtld_exit;
567 return (func_ptr_type) obj_main->entry;
571 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
576 ptr = (void *)make_function_pointer(def, obj);
577 target = ((Elf_Addr (*)(void))ptr)();
578 return ((void *)target);
582 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
586 const Obj_Entry *defobj;
589 RtldLockState lockstate;
591 rlock_acquire(rtld_bind_lock, &lockstate);
592 if (sigsetjmp(lockstate.env, 0) != 0)
593 lock_upgrade(rtld_bind_lock, &lockstate);
595 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
597 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
599 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
600 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
604 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
605 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
607 target = (Elf_Addr)(defobj->relocbase + def->st_value);
609 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
610 defobj->strtab + def->st_name, basename(obj->path),
611 (void *)target, basename(defobj->path));
614 * Write the new contents for the jmpslot. Note that depending on
615 * architecture, the value which we need to return back to the
616 * lazy binding trampoline may or may not be the target
617 * address. The value returned from reloc_jmpslot() is the value
618 * that the trampoline needs.
620 target = reloc_jmpslot(where, target, defobj, obj, rel);
621 lock_release(rtld_bind_lock, &lockstate);
626 * Error reporting function. Use it like printf. If formats the message
627 * into a buffer, and sets things up so that the next call to dlerror()
628 * will return the message.
631 _rtld_error(const char *fmt, ...)
633 static char buf[512];
637 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
643 * Return a dynamically-allocated copy of the current error message, if any.
648 return error_message == NULL ? NULL : xstrdup(error_message);
652 * Restore the current error message from a copy which was previously saved
653 * by errmsg_save(). The copy is freed.
656 errmsg_restore(char *saved_msg)
658 if (saved_msg == NULL)
659 error_message = NULL;
661 _rtld_error("%s", saved_msg);
667 basename(const char *name)
669 const char *p = strrchr(name, '/');
670 return p != NULL ? p + 1 : name;
673 static struct utsname uts;
676 origin_subst_one(char **res, const char *real, const char *kw, const char *subst,
686 subst_len = kw_len = 0;
690 if (subst_len == 0) {
691 subst_len = strlen(subst);
695 *res = xmalloc(PATH_MAX);
698 if ((res1 - *res) + subst_len + (p1 - p) >= PATH_MAX) {
699 _rtld_error("Substitution of %s in %s cannot be performed",
701 if (may_free != NULL)
706 memcpy(res1, p, p1 - p);
708 memcpy(res1, subst, subst_len);
713 if (may_free != NULL)
716 *res = xstrdup(real);
720 if (may_free != NULL)
722 if (strlcat(res1, p, PATH_MAX - (res1 - *res)) >= PATH_MAX) {
732 origin_subst(const char *real, const char *origin_path)
734 char *res1, *res2, *res3, *res4;
736 if (uts.sysname[0] == '\0') {
737 if (uname(&uts) != 0) {
738 _rtld_error("utsname failed: %d", errno);
742 if (!origin_subst_one(&res1, real, "$ORIGIN", origin_path, NULL) ||
743 !origin_subst_one(&res2, res1, "$OSNAME", uts.sysname, res1) ||
744 !origin_subst_one(&res3, res2, "$OSREL", uts.release, res2) ||
745 !origin_subst_one(&res4, res3, "$PLATFORM", uts.machine, res3))
753 const char *msg = dlerror();
757 rtld_fdputstr(STDERR_FILENO, msg);
762 * Process a shared object's DYNAMIC section, and save the important
763 * information in its Obj_Entry structure.
766 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
767 const Elf_Dyn **dyn_soname)
770 Needed_Entry **needed_tail = &obj->needed;
771 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
772 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
773 int plttype = DT_REL;
778 obj->bind_now = false;
779 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
780 switch (dynp->d_tag) {
783 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
787 obj->relsize = dynp->d_un.d_val;
791 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
795 obj->pltrel = (const Elf_Rel *)
796 (obj->relocbase + dynp->d_un.d_ptr);
800 obj->pltrelsize = dynp->d_un.d_val;
804 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
808 obj->relasize = dynp->d_un.d_val;
812 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
816 plttype = dynp->d_un.d_val;
817 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
821 obj->symtab = (const Elf_Sym *)
822 (obj->relocbase + dynp->d_un.d_ptr);
826 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
830 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
834 obj->strsize = dynp->d_un.d_val;
838 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
843 obj->verneednum = dynp->d_un.d_val;
847 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
852 obj->verdefnum = dynp->d_un.d_val;
856 obj->versyms = (const Elf_Versym *)(obj->relocbase +
862 const Elf_Hashelt *hashtab = (const Elf_Hashelt *)
863 (obj->relocbase + dynp->d_un.d_ptr);
864 obj->nbuckets = hashtab[0];
865 obj->nchains = hashtab[1];
866 obj->buckets = hashtab + 2;
867 obj->chains = obj->buckets + obj->nbuckets;
873 Needed_Entry *nep = NEW(Needed_Entry);
874 nep->name = dynp->d_un.d_val;
879 needed_tail = &nep->next;
885 Needed_Entry *nep = NEW(Needed_Entry);
886 nep->name = dynp->d_un.d_val;
890 *needed_filtees_tail = nep;
891 needed_filtees_tail = &nep->next;
897 Needed_Entry *nep = NEW(Needed_Entry);
898 nep->name = dynp->d_un.d_val;
902 *needed_aux_filtees_tail = nep;
903 needed_aux_filtees_tail = &nep->next;
908 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
916 obj->symbolic = true;
920 case DT_RUNPATH: /* XXX: process separately */
922 * We have to wait until later to process this, because we
923 * might not have gotten the address of the string table yet.
933 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
937 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
941 * Don't process DT_DEBUG on MIPS as the dynamic section
942 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
947 /* XXX - not implemented yet */
949 dbg("Filling in DT_DEBUG entry");
950 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
955 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
956 obj->z_origin = true;
957 if (dynp->d_un.d_val & DF_SYMBOLIC)
958 obj->symbolic = true;
959 if (dynp->d_un.d_val & DF_TEXTREL)
961 if (dynp->d_un.d_val & DF_BIND_NOW)
962 obj->bind_now = true;
963 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
967 case DT_MIPS_LOCAL_GOTNO:
968 obj->local_gotno = dynp->d_un.d_val;
971 case DT_MIPS_SYMTABNO:
972 obj->symtabno = dynp->d_un.d_val;
976 obj->gotsym = dynp->d_un.d_val;
979 case DT_MIPS_RLD_MAP:
982 dbg("Filling in DT_DEBUG entry");
983 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
989 if (dynp->d_un.d_val & DF_1_NOOPEN)
990 obj->z_noopen = true;
991 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
992 obj->z_origin = true;
993 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
995 if (dynp->d_un.d_val & DF_1_BIND_NOW)
996 obj->bind_now = true;
997 if (dynp->d_un.d_val & DF_1_NODELETE)
998 obj->z_nodelete = true;
999 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1000 obj->z_loadfltr = true;
1005 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1012 obj->traced = false;
1014 if (plttype == DT_RELA) {
1015 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1017 obj->pltrelasize = obj->pltrelsize;
1018 obj->pltrelsize = 0;
1023 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1024 const Elf_Dyn *dyn_soname)
1027 if (obj->z_origin && obj->origin_path == NULL) {
1028 obj->origin_path = xmalloc(PATH_MAX);
1029 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1033 if (dyn_rpath != NULL) {
1034 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1036 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1039 if (dyn_soname != NULL)
1040 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1044 digest_dynamic(Obj_Entry *obj, int early)
1046 const Elf_Dyn *dyn_rpath;
1047 const Elf_Dyn *dyn_soname;
1049 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname);
1050 digest_dynamic2(obj, dyn_rpath, dyn_soname);
1054 * Process a shared object's program header. This is used only for the
1055 * main program, when the kernel has already loaded the main program
1056 * into memory before calling the dynamic linker. It creates and
1057 * returns an Obj_Entry structure.
1060 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1063 const Elf_Phdr *phlimit = phdr + phnum;
1068 for (ph = phdr; ph < phlimit; ph++) {
1069 if (ph->p_type != PT_PHDR)
1073 obj->phsize = ph->p_memsz;
1074 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1078 obj->stack_flags = PF_X | PF_R | PF_W;
1080 for (ph = phdr; ph < phlimit; ph++) {
1081 switch (ph->p_type) {
1084 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1088 if (nsegs == 0) { /* First load segment */
1089 obj->vaddrbase = trunc_page(ph->p_vaddr);
1090 obj->mapbase = obj->vaddrbase + obj->relocbase;
1091 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1093 } else { /* Last load segment */
1094 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1101 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1106 obj->tlssize = ph->p_memsz;
1107 obj->tlsalign = ph->p_align;
1108 obj->tlsinitsize = ph->p_filesz;
1109 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1113 obj->stack_flags = ph->p_flags;
1118 _rtld_error("%s: too few PT_LOAD segments", path);
1127 dlcheck(void *handle)
1131 for (obj = obj_list; obj != NULL; obj = obj->next)
1132 if (obj == (Obj_Entry *) handle)
1135 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1136 _rtld_error("Invalid shared object handle %p", handle);
1143 * If the given object is already in the donelist, return true. Otherwise
1144 * add the object to the list and return false.
1147 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1151 for (i = 0; i < dlp->num_used; i++)
1152 if (dlp->objs[i] == obj)
1155 * Our donelist allocation should always be sufficient. But if
1156 * our threads locking isn't working properly, more shared objects
1157 * could have been loaded since we allocated the list. That should
1158 * never happen, but we'll handle it properly just in case it does.
1160 if (dlp->num_used < dlp->num_alloc)
1161 dlp->objs[dlp->num_used++] = obj;
1166 * Hash function for symbol table lookup. Don't even think about changing
1167 * this. It is specified by the System V ABI.
1170 elf_hash(const char *name)
1172 const unsigned char *p = (const unsigned char *) name;
1173 unsigned long h = 0;
1176 while (*p != '\0') {
1177 h = (h << 4) + *p++;
1178 if ((g = h & 0xf0000000) != 0)
1186 * Find the library with the given name, and return its full pathname.
1187 * The returned string is dynamically allocated. Generates an error
1188 * message and returns NULL if the library cannot be found.
1190 * If the second argument is non-NULL, then it refers to an already-
1191 * loaded shared object, whose library search path will be searched.
1193 * The search order is:
1195 * rpath in the referencing file
1200 find_library(const char *xname, const Obj_Entry *refobj)
1205 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1206 if (xname[0] != '/' && !trust) {
1207 _rtld_error("Absolute pathname required for shared object \"%s\"",
1211 if (refobj != NULL && refobj->z_origin)
1212 return origin_subst(xname, refobj->origin_path);
1214 return xstrdup(xname);
1217 if (libmap_disable || (refobj == NULL) ||
1218 (name = lm_find(refobj->path, xname)) == NULL)
1219 name = (char *)xname;
1221 dbg(" Searching for \"%s\"", name);
1223 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
1225 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1226 (pathname = search_library_path(name, gethints())) != NULL ||
1227 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
1230 if(refobj != NULL && refobj->path != NULL) {
1231 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1232 name, basename(refobj->path));
1234 _rtld_error("Shared object \"%s\" not found", name);
1240 * Given a symbol number in a referencing object, find the corresponding
1241 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1242 * no definition was found. Returns a pointer to the Obj_Entry of the
1243 * defining object via the reference parameter DEFOBJ_OUT.
1246 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1247 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1248 RtldLockState *lockstate)
1252 const Obj_Entry *defobj;
1258 * If we have already found this symbol, get the information from
1261 if (symnum >= refobj->nchains)
1262 return NULL; /* Bad object */
1263 if (cache != NULL && cache[symnum].sym != NULL) {
1264 *defobj_out = cache[symnum].obj;
1265 return cache[symnum].sym;
1268 ref = refobj->symtab + symnum;
1269 name = refobj->strtab + ref->st_name;
1274 * We don't have to do a full scale lookup if the symbol is local.
1275 * We know it will bind to the instance in this load module; to
1276 * which we already have a pointer (ie ref). By not doing a lookup,
1277 * we not only improve performance, but it also avoids unresolvable
1278 * symbols when local symbols are not in the hash table. This has
1279 * been seen with the ia64 toolchain.
1281 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1282 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1283 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1286 symlook_init(&req, name);
1288 req.ventry = fetch_ventry(refobj, symnum);
1289 req.lockstate = lockstate;
1290 res = symlook_default(&req, refobj);
1293 defobj = req.defobj_out;
1301 * If we found no definition and the reference is weak, treat the
1302 * symbol as having the value zero.
1304 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1310 *defobj_out = defobj;
1311 /* Record the information in the cache to avoid subsequent lookups. */
1312 if (cache != NULL) {
1313 cache[symnum].sym = def;
1314 cache[symnum].obj = defobj;
1317 if (refobj != &obj_rtld)
1318 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1324 * Return the search path from the ldconfig hints file, reading it if
1325 * necessary. Returns NULL if there are problems with the hints file,
1326 * or if the search path there is empty.
1333 if (hints == NULL) {
1335 struct elfhints_hdr hdr;
1338 /* Keep from trying again in case the hints file is bad. */
1341 if ((fd = open(ld_elf_hints_path, O_RDONLY)) == -1)
1343 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1344 hdr.magic != ELFHINTS_MAGIC ||
1349 p = xmalloc(hdr.dirlistlen + 1);
1350 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1351 read(fd, p, hdr.dirlistlen + 1) != (ssize_t)hdr.dirlistlen + 1) {
1359 return hints[0] != '\0' ? hints : NULL;
1363 init_dag(Obj_Entry *root)
1365 const Needed_Entry *needed;
1366 const Objlist_Entry *elm;
1369 if (root->dag_inited)
1371 donelist_init(&donelist);
1373 /* Root object belongs to own DAG. */
1374 objlist_push_tail(&root->dldags, root);
1375 objlist_push_tail(&root->dagmembers, root);
1376 donelist_check(&donelist, root);
1379 * Add dependencies of root object to DAG in breadth order
1380 * by exploiting the fact that each new object get added
1381 * to the tail of the dagmembers list.
1383 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1384 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1385 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1387 objlist_push_tail(&needed->obj->dldags, root);
1388 objlist_push_tail(&root->dagmembers, needed->obj);
1391 root->dag_inited = true;
1395 * Initialize the dynamic linker. The argument is the address at which
1396 * the dynamic linker has been mapped into memory. The primary task of
1397 * this function is to relocate the dynamic linker.
1400 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1402 Obj_Entry objtmp; /* Temporary rtld object */
1403 const Elf_Dyn *dyn_rpath;
1404 const Elf_Dyn *dyn_soname;
1407 * Conjure up an Obj_Entry structure for the dynamic linker.
1409 * The "path" member can't be initialized yet because string constants
1410 * cannot yet be accessed. Below we will set it correctly.
1412 memset(&objtmp, 0, sizeof(objtmp));
1415 objtmp.mapbase = mapbase;
1417 objtmp.relocbase = mapbase;
1419 if (RTLD_IS_DYNAMIC()) {
1420 objtmp.dynamic = rtld_dynamic(&objtmp);
1421 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname);
1422 assert(objtmp.needed == NULL);
1423 #if !defined(__mips__)
1424 /* MIPS has a bogus DT_TEXTREL. */
1425 assert(!objtmp.textrel);
1429 * Temporarily put the dynamic linker entry into the object list, so
1430 * that symbols can be found.
1433 relocate_objects(&objtmp, true, &objtmp, NULL);
1436 /* Initialize the object list. */
1437 obj_tail = &obj_list;
1439 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1440 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1442 if (aux_info[AT_PAGESZ] != NULL)
1443 pagesize = aux_info[AT_PAGESZ]->a_un.a_val;
1444 if (aux_info[AT_OSRELDATE] != NULL)
1445 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1447 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname);
1449 /* Replace the path with a dynamically allocated copy. */
1450 obj_rtld.path = xstrdup(PATH_RTLD);
1452 r_debug.r_brk = r_debug_state;
1453 r_debug.r_state = RT_CONSISTENT;
1457 * Add the init functions from a needed object list (and its recursive
1458 * needed objects) to "list". This is not used directly; it is a helper
1459 * function for initlist_add_objects(). The write lock must be held
1460 * when this function is called.
1463 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1465 /* Recursively process the successor needed objects. */
1466 if (needed->next != NULL)
1467 initlist_add_neededs(needed->next, list);
1469 /* Process the current needed object. */
1470 if (needed->obj != NULL)
1471 initlist_add_objects(needed->obj, &needed->obj->next, list);
1475 * Scan all of the DAGs rooted in the range of objects from "obj" to
1476 * "tail" and add their init functions to "list". This recurses over
1477 * the DAGs and ensure the proper init ordering such that each object's
1478 * needed libraries are initialized before the object itself. At the
1479 * same time, this function adds the objects to the global finalization
1480 * list "list_fini" in the opposite order. The write lock must be
1481 * held when this function is called.
1484 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1486 if (obj->init_scanned || obj->init_done)
1488 obj->init_scanned = true;
1490 /* Recursively process the successor objects. */
1491 if (&obj->next != tail)
1492 initlist_add_objects(obj->next, tail, list);
1494 /* Recursively process the needed objects. */
1495 if (obj->needed != NULL)
1496 initlist_add_neededs(obj->needed, list);
1498 /* Add the object to the init list. */
1499 if (obj->init != (Elf_Addr)NULL)
1500 objlist_push_tail(list, obj);
1502 /* Add the object to the global fini list in the reverse order. */
1503 if (obj->fini != (Elf_Addr)NULL && !obj->on_fini_list) {
1504 objlist_push_head(&list_fini, obj);
1505 obj->on_fini_list = true;
1510 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1514 free_needed_filtees(Needed_Entry *n)
1516 Needed_Entry *needed, *needed1;
1518 for (needed = n; needed != NULL; needed = needed->next) {
1519 if (needed->obj != NULL) {
1520 dlclose(needed->obj);
1524 for (needed = n; needed != NULL; needed = needed1) {
1525 needed1 = needed->next;
1531 unload_filtees(Obj_Entry *obj)
1534 free_needed_filtees(obj->needed_filtees);
1535 obj->needed_filtees = NULL;
1536 free_needed_filtees(obj->needed_aux_filtees);
1537 obj->needed_aux_filtees = NULL;
1538 obj->filtees_loaded = false;
1542 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags)
1545 for (; needed != NULL; needed = needed->next) {
1546 needed->obj = dlopen_object(obj->strtab + needed->name, obj,
1547 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1553 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
1556 lock_restart_for_upgrade(lockstate);
1557 if (!obj->filtees_loaded) {
1558 load_filtee1(obj, obj->needed_filtees, flags);
1559 load_filtee1(obj, obj->needed_aux_filtees, flags);
1560 obj->filtees_loaded = true;
1565 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
1569 for (; needed != NULL; needed = needed->next) {
1570 obj1 = needed->obj = load_object(obj->strtab + needed->name, obj,
1571 flags & ~RTLD_LO_NOLOAD);
1572 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
1574 if (obj1 != NULL && obj1->z_nodelete && !obj1->ref_nodel) {
1575 dbg("obj %s nodelete", obj1->path);
1578 obj1->ref_nodel = true;
1585 * Given a shared object, traverse its list of needed objects, and load
1586 * each of them. Returns 0 on success. Generates an error message and
1587 * returns -1 on failure.
1590 load_needed_objects(Obj_Entry *first, int flags)
1594 for (obj = first; obj != NULL; obj = obj->next) {
1595 if (process_needed(obj, obj->needed, flags) == -1)
1602 load_preload_objects(void)
1604 char *p = ld_preload;
1605 static const char delim[] = " \t:;";
1610 p += strspn(p, delim);
1611 while (*p != '\0') {
1612 size_t len = strcspn(p, delim);
1617 if (load_object(p, NULL, 0) == NULL)
1618 return -1; /* XXX - cleanup */
1621 p += strspn(p, delim);
1623 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
1628 * Load a shared object into memory, if it is not already loaded.
1630 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1634 load_object(const char *name, const Obj_Entry *refobj, int flags)
1641 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1642 if (object_match_name(obj, name))
1645 path = find_library(name, refobj);
1650 * If we didn't find a match by pathname, open the file and check
1651 * again by device and inode. This avoids false mismatches caused
1652 * by multiple links or ".." in pathnames.
1654 * To avoid a race, we open the file and use fstat() rather than
1657 if ((fd = open(path, O_RDONLY)) == -1) {
1658 _rtld_error("Cannot open \"%s\"", path);
1662 if (fstat(fd, &sb) == -1) {
1663 _rtld_error("Cannot fstat \"%s\"", path);
1668 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1669 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
1672 object_add_name(obj, name);
1677 if (flags & RTLD_LO_NOLOAD) {
1683 /* First use of this object, so we must map it in */
1684 obj = do_load_object(fd, name, path, &sb, flags);
1693 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
1700 * but first, make sure that environment variables haven't been
1701 * used to circumvent the noexec flag on a filesystem.
1703 if (dangerous_ld_env) {
1704 if (fstatfs(fd, &fs) != 0) {
1705 _rtld_error("Cannot fstatfs \"%s\"", path);
1708 if (fs.f_flags & MNT_NOEXEC) {
1709 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
1713 dbg("loading \"%s\"", path);
1714 obj = map_object(fd, path, sbp);
1718 object_add_name(obj, name);
1720 digest_dynamic(obj, 0);
1721 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
1723 dbg("refusing to load non-loadable \"%s\"", obj->path);
1724 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
1725 munmap(obj->mapbase, obj->mapsize);
1731 obj_tail = &obj->next;
1734 linkmap_add(obj); /* for GDB & dlinfo() */
1735 max_stack_flags |= obj->stack_flags;
1737 dbg(" %p .. %p: %s", obj->mapbase,
1738 obj->mapbase + obj->mapsize - 1, obj->path);
1740 dbg(" WARNING: %s has impure text", obj->path);
1741 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
1748 obj_from_addr(const void *addr)
1752 for (obj = obj_list; obj != NULL; obj = obj->next) {
1753 if (addr < (void *) obj->mapbase)
1755 if (addr < (void *) (obj->mapbase + obj->mapsize))
1762 * Call the finalization functions for each of the objects in "list"
1763 * belonging to the DAG of "root" and referenced once. If NULL "root"
1764 * is specified, every finalization function will be called regardless
1765 * of the reference count and the list elements won't be freed. All of
1766 * the objects are expected to have non-NULL fini functions.
1769 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
1774 assert(root == NULL || root->refcount == 1);
1777 * Preserve the current error message since a fini function might
1778 * call into the dynamic linker and overwrite it.
1780 saved_msg = errmsg_save();
1782 STAILQ_FOREACH(elm, list, link) {
1783 if (root != NULL && (elm->obj->refcount != 1 ||
1784 objlist_find(&root->dagmembers, elm->obj) == NULL))
1786 dbg("calling fini function for %s at %p", elm->obj->path,
1787 (void *)elm->obj->fini);
1788 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0,
1790 /* Remove object from fini list to prevent recursive invocation. */
1791 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1793 * XXX: If a dlopen() call references an object while the
1794 * fini function is in progress, we might end up trying to
1795 * unload the referenced object in dlclose() or the object
1796 * won't be unloaded although its fini function has been
1799 lock_release(rtld_bind_lock, lockstate);
1800 call_initfini_pointer(elm->obj, elm->obj->fini);
1801 wlock_acquire(rtld_bind_lock, lockstate);
1802 /* No need to free anything if process is going down. */
1806 * We must restart the list traversal after every fini call
1807 * because a dlclose() call from the fini function or from
1808 * another thread might have modified the reference counts.
1812 } while (elm != NULL);
1813 errmsg_restore(saved_msg);
1817 * Call the initialization functions for each of the objects in
1818 * "list". All of the objects are expected to have non-NULL init
1822 objlist_call_init(Objlist *list, RtldLockState *lockstate)
1829 * Clean init_scanned flag so that objects can be rechecked and
1830 * possibly initialized earlier if any of vectors called below
1831 * cause the change by using dlopen.
1833 for (obj = obj_list; obj != NULL; obj = obj->next)
1834 obj->init_scanned = false;
1837 * Preserve the current error message since an init function might
1838 * call into the dynamic linker and overwrite it.
1840 saved_msg = errmsg_save();
1841 STAILQ_FOREACH(elm, list, link) {
1842 if (elm->obj->init_done) /* Initialized early. */
1844 dbg("calling init function for %s at %p", elm->obj->path,
1845 (void *)elm->obj->init);
1846 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0,
1849 * Race: other thread might try to use this object before current
1850 * one completes the initilization. Not much can be done here
1851 * without better locking.
1853 elm->obj->init_done = true;
1854 lock_release(rtld_bind_lock, lockstate);
1855 call_initfini_pointer(elm->obj, elm->obj->init);
1856 wlock_acquire(rtld_bind_lock, lockstate);
1858 errmsg_restore(saved_msg);
1862 objlist_clear(Objlist *list)
1866 while (!STAILQ_EMPTY(list)) {
1867 elm = STAILQ_FIRST(list);
1868 STAILQ_REMOVE_HEAD(list, link);
1873 static Objlist_Entry *
1874 objlist_find(Objlist *list, const Obj_Entry *obj)
1878 STAILQ_FOREACH(elm, list, link)
1879 if (elm->obj == obj)
1885 objlist_init(Objlist *list)
1891 objlist_push_head(Objlist *list, Obj_Entry *obj)
1895 elm = NEW(Objlist_Entry);
1897 STAILQ_INSERT_HEAD(list, elm, link);
1901 objlist_push_tail(Objlist *list, Obj_Entry *obj)
1905 elm = NEW(Objlist_Entry);
1907 STAILQ_INSERT_TAIL(list, elm, link);
1911 objlist_remove(Objlist *list, Obj_Entry *obj)
1915 if ((elm = objlist_find(list, obj)) != NULL) {
1916 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1922 * Relocate newly-loaded shared objects. The argument is a pointer to
1923 * the Obj_Entry for the first such object. All objects from the first
1924 * to the end of the list of objects are relocated. Returns 0 on success,
1928 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
1929 RtldLockState *lockstate)
1933 for (obj = first; obj != NULL; obj = obj->next) {
1935 dbg("relocating \"%s\"", obj->path);
1936 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
1937 obj->symtab == NULL || obj->strtab == NULL) {
1938 _rtld_error("%s: Shared object has no run-time symbol table",
1944 /* There are relocations to the write-protected text segment. */
1945 if (mprotect(obj->mapbase, obj->textsize,
1946 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
1947 _rtld_error("%s: Cannot write-enable text segment: %s",
1948 obj->path, strerror(errno));
1953 /* Process the non-PLT relocations. */
1954 if (reloc_non_plt(obj, rtldobj, lockstate))
1957 if (obj->textrel) { /* Re-protected the text segment. */
1958 if (mprotect(obj->mapbase, obj->textsize,
1959 PROT_READ|PROT_EXEC) == -1) {
1960 _rtld_error("%s: Cannot write-protect text segment: %s",
1961 obj->path, strerror(errno));
1967 /* Set the special PLT or GOT entries. */
1970 /* Process the PLT relocations. */
1971 if (reloc_plt(obj) == -1)
1973 /* Relocate the jump slots if we are doing immediate binding. */
1974 if (obj->bind_now || bind_now)
1975 if (reloc_jmpslots(obj, lockstate) == -1)
1979 * Set up the magic number and version in the Obj_Entry. These
1980 * were checked in the crt1.o from the original ElfKit, so we
1981 * set them for backward compatibility.
1983 obj->magic = RTLD_MAGIC;
1984 obj->version = RTLD_VERSION;
1991 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
1992 * referencing STT_GNU_IFUNC symbols is postponed till the other
1993 * relocations are done. The indirect functions specified as
1994 * ifunc are allowed to call other symbols, so we need to have
1995 * objects relocated before asking for resolution from indirects.
1997 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
1998 * instead of the usual lazy handling of PLT slots. It is
1999 * consistent with how GNU does it.
2002 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, RtldLockState *lockstate)
2004 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2006 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2007 reloc_gnu_ifunc(obj, lockstate) == -1)
2013 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, RtldLockState *lockstate)
2017 for (obj = first; obj != NULL; obj = obj->next) {
2018 if (resolve_object_ifunc(obj, bind_now, lockstate) == -1)
2025 initlist_objects_ifunc(Objlist *list, bool bind_now, RtldLockState *lockstate)
2029 STAILQ_FOREACH(elm, list, link) {
2030 if (resolve_object_ifunc(elm->obj, bind_now, lockstate) == -1)
2037 * Cleanup procedure. It will be called (by the atexit mechanism) just
2038 * before the process exits.
2043 RtldLockState lockstate;
2045 wlock_acquire(rtld_bind_lock, &lockstate);
2047 objlist_call_fini(&list_fini, NULL, &lockstate);
2048 /* No need to remove the items from the list, since we are exiting. */
2049 if (!libmap_disable)
2051 lock_release(rtld_bind_lock, &lockstate);
2055 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2063 path += strspn(path, ":;");
2064 while (*path != '\0') {
2068 len = strcspn(path, ":;");
2070 trans = lm_findn(NULL, path, len);
2072 res = callback(trans, strlen(trans), arg);
2075 res = callback(path, len, arg);
2081 path += strspn(path, ":;");
2087 struct try_library_args {
2095 try_library_path(const char *dir, size_t dirlen, void *param)
2097 struct try_library_args *arg;
2100 if (*dir == '/' || trust) {
2103 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2106 pathname = arg->buffer;
2107 strncpy(pathname, dir, dirlen);
2108 pathname[dirlen] = '/';
2109 strcpy(pathname + dirlen + 1, arg->name);
2111 dbg(" Trying \"%s\"", pathname);
2112 if (access(pathname, F_OK) == 0) { /* We found it */
2113 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2114 strcpy(pathname, arg->buffer);
2122 search_library_path(const char *name, const char *path)
2125 struct try_library_args arg;
2131 arg.namelen = strlen(name);
2132 arg.buffer = xmalloc(PATH_MAX);
2133 arg.buflen = PATH_MAX;
2135 p = path_enumerate(path, try_library_path, &arg);
2143 dlclose(void *handle)
2146 RtldLockState lockstate;
2148 wlock_acquire(rtld_bind_lock, &lockstate);
2149 root = dlcheck(handle);
2151 lock_release(rtld_bind_lock, &lockstate);
2154 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2157 /* Unreference the object and its dependencies. */
2158 root->dl_refcount--;
2160 if (root->refcount == 1) {
2162 * The object will be no longer referenced, so we must unload it.
2163 * First, call the fini functions.
2165 objlist_call_fini(&list_fini, root, &lockstate);
2169 /* Finish cleaning up the newly-unreferenced objects. */
2170 GDB_STATE(RT_DELETE,&root->linkmap);
2171 unload_object(root);
2172 GDB_STATE(RT_CONSISTENT,NULL);
2176 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2177 lock_release(rtld_bind_lock, &lockstate);
2184 char *msg = error_message;
2185 error_message = NULL;
2190 * This function is deprecated and has no effect.
2193 dllockinit(void *context,
2194 void *(*lock_create)(void *context),
2195 void (*rlock_acquire)(void *lock),
2196 void (*wlock_acquire)(void *lock),
2197 void (*lock_release)(void *lock),
2198 void (*lock_destroy)(void *lock),
2199 void (*context_destroy)(void *context))
2201 static void *cur_context;
2202 static void (*cur_context_destroy)(void *);
2204 /* Just destroy the context from the previous call, if necessary. */
2205 if (cur_context_destroy != NULL)
2206 cur_context_destroy(cur_context);
2207 cur_context = context;
2208 cur_context_destroy = context_destroy;
2212 dlopen(const char *name, int mode)
2214 RtldLockState lockstate;
2217 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2218 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2219 if (ld_tracing != NULL) {
2220 rlock_acquire(rtld_bind_lock, &lockstate);
2221 if (sigsetjmp(lockstate.env, 0) != 0)
2222 lock_upgrade(rtld_bind_lock, &lockstate);
2223 environ = (char **)*get_program_var_addr("environ", &lockstate);
2224 lock_release(rtld_bind_lock, &lockstate);
2226 lo_flags = RTLD_LO_DLOPEN;
2227 if (mode & RTLD_NODELETE)
2228 lo_flags |= RTLD_LO_NODELETE;
2229 if (mode & RTLD_NOLOAD)
2230 lo_flags |= RTLD_LO_NOLOAD;
2231 if (ld_tracing != NULL)
2232 lo_flags |= RTLD_LO_TRACE;
2234 return (dlopen_object(name, obj_main, lo_flags,
2235 mode & (RTLD_MODEMASK | RTLD_GLOBAL)));
2239 dlopen_cleanup(Obj_Entry *obj)
2244 if (obj->refcount == 0)
2249 dlopen_object(const char *name, Obj_Entry *refobj, int lo_flags, int mode)
2251 Obj_Entry **old_obj_tail;
2254 RtldLockState lockstate;
2257 objlist_init(&initlist);
2259 wlock_acquire(rtld_bind_lock, &lockstate);
2260 GDB_STATE(RT_ADD,NULL);
2262 old_obj_tail = obj_tail;
2268 obj = load_object(name, refobj, lo_flags);
2273 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2274 objlist_push_tail(&list_global, obj);
2275 if (*old_obj_tail != NULL) { /* We loaded something new. */
2276 assert(*old_obj_tail == obj);
2277 result = load_needed_objects(obj, lo_flags & RTLD_LO_DLOPEN);
2281 result = rtld_verify_versions(&obj->dagmembers);
2282 if (result != -1 && ld_tracing)
2284 if (result == -1 || (relocate_objects(obj, (mode & RTLD_MODEMASK)
2285 == RTLD_NOW, &obj_rtld, &lockstate)) == -1) {
2286 dlopen_cleanup(obj);
2289 /* Make list of init functions to call. */
2290 initlist_add_objects(obj, &obj->next, &initlist);
2295 * Bump the reference counts for objects on this DAG. If
2296 * this is the first dlopen() call for the object that was
2297 * already loaded as a dependency, initialize the dag
2303 if ((lo_flags & RTLD_LO_TRACE) != 0)
2306 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2307 obj->z_nodelete) && !obj->ref_nodel) {
2308 dbg("obj %s nodelete", obj->path);
2310 obj->z_nodelete = obj->ref_nodel = true;
2314 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2316 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2318 map_stacks_exec(&lockstate);
2320 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2321 &lockstate) == -1) {
2322 objlist_clear(&initlist);
2323 dlopen_cleanup(obj);
2324 lock_release(rtld_bind_lock, &lockstate);
2328 /* Call the init functions. */
2329 objlist_call_init(&initlist, &lockstate);
2330 objlist_clear(&initlist);
2331 lock_release(rtld_bind_lock, &lockstate);
2334 trace_loaded_objects(obj);
2335 lock_release(rtld_bind_lock, &lockstate);
2340 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
2344 const Obj_Entry *obj, *defobj;
2347 RtldLockState lockstate;
2352 symlook_init(&req, name);
2354 req.flags = flags | SYMLOOK_IN_PLT;
2355 req.lockstate = &lockstate;
2357 rlock_acquire(rtld_bind_lock, &lockstate);
2358 if (sigsetjmp(lockstate.env, 0) != 0)
2359 lock_upgrade(rtld_bind_lock, &lockstate);
2360 if (handle == NULL || handle == RTLD_NEXT ||
2361 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
2363 if ((obj = obj_from_addr(retaddr)) == NULL) {
2364 _rtld_error("Cannot determine caller's shared object");
2365 lock_release(rtld_bind_lock, &lockstate);
2368 if (handle == NULL) { /* Just the caller's shared object. */
2369 res = symlook_obj(&req, obj);
2372 defobj = req.defobj_out;
2374 } else if (handle == RTLD_NEXT || /* Objects after caller's */
2375 handle == RTLD_SELF) { /* ... caller included */
2376 if (handle == RTLD_NEXT)
2378 for (; obj != NULL; obj = obj->next) {
2379 res = symlook_obj(&req, obj);
2382 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
2384 defobj = req.defobj_out;
2385 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2391 * Search the dynamic linker itself, and possibly resolve the
2392 * symbol from there. This is how the application links to
2393 * dynamic linker services such as dlopen.
2395 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2396 res = symlook_obj(&req, &obj_rtld);
2399 defobj = req.defobj_out;
2403 assert(handle == RTLD_DEFAULT);
2404 res = symlook_default(&req, obj);
2406 defobj = req.defobj_out;
2411 if ((obj = dlcheck(handle)) == NULL) {
2412 lock_release(rtld_bind_lock, &lockstate);
2416 donelist_init(&donelist);
2417 if (obj->mainprog) {
2418 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
2419 res = symlook_global(&req, &donelist);
2422 defobj = req.defobj_out;
2425 * Search the dynamic linker itself, and possibly resolve the
2426 * symbol from there. This is how the application links to
2427 * dynamic linker services such as dlopen.
2429 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2430 res = symlook_obj(&req, &obj_rtld);
2433 defobj = req.defobj_out;
2438 /* Search the whole DAG rooted at the given object. */
2439 res = symlook_list(&req, &obj->dagmembers, &donelist);
2442 defobj = req.defobj_out;
2448 lock_release(rtld_bind_lock, &lockstate);
2451 * The value required by the caller is derived from the value
2452 * of the symbol. For the ia64 architecture, we need to
2453 * construct a function descriptor which the caller can use to
2454 * call the function with the right 'gp' value. For other
2455 * architectures and for non-functions, the value is simply
2456 * the relocated value of the symbol.
2458 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
2459 return (make_function_pointer(def, defobj));
2460 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
2461 return (rtld_resolve_ifunc(defobj, def));
2463 return (defobj->relocbase + def->st_value);
2466 _rtld_error("Undefined symbol \"%s\"", name);
2467 lock_release(rtld_bind_lock, &lockstate);
2472 dlsym(void *handle, const char *name)
2474 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
2479 dlfunc(void *handle, const char *name)
2486 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
2492 dlvsym(void *handle, const char *name, const char *version)
2496 ventry.name = version;
2498 ventry.hash = elf_hash(version);
2500 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
2505 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
2507 const Obj_Entry *obj;
2508 RtldLockState lockstate;
2510 rlock_acquire(rtld_bind_lock, &lockstate);
2511 obj = obj_from_addr(addr);
2513 _rtld_error("No shared object contains address");
2514 lock_release(rtld_bind_lock, &lockstate);
2517 rtld_fill_dl_phdr_info(obj, phdr_info);
2518 lock_release(rtld_bind_lock, &lockstate);
2523 dladdr(const void *addr, Dl_info *info)
2525 const Obj_Entry *obj;
2528 unsigned long symoffset;
2529 RtldLockState lockstate;
2531 rlock_acquire(rtld_bind_lock, &lockstate);
2532 obj = obj_from_addr(addr);
2534 _rtld_error("No shared object contains address");
2535 lock_release(rtld_bind_lock, &lockstate);
2538 info->dli_fname = obj->path;
2539 info->dli_fbase = obj->mapbase;
2540 info->dli_saddr = (void *)0;
2541 info->dli_sname = NULL;
2544 * Walk the symbol list looking for the symbol whose address is
2545 * closest to the address sent in.
2547 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
2548 def = obj->symtab + symoffset;
2551 * For skip the symbol if st_shndx is either SHN_UNDEF or
2554 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
2558 * If the symbol is greater than the specified address, or if it
2559 * is further away from addr than the current nearest symbol,
2562 symbol_addr = obj->relocbase + def->st_value;
2563 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
2566 /* Update our idea of the nearest symbol. */
2567 info->dli_sname = obj->strtab + def->st_name;
2568 info->dli_saddr = symbol_addr;
2571 if (info->dli_saddr == addr)
2574 lock_release(rtld_bind_lock, &lockstate);
2579 dlinfo(void *handle, int request, void *p)
2581 const Obj_Entry *obj;
2582 RtldLockState lockstate;
2585 rlock_acquire(rtld_bind_lock, &lockstate);
2587 if (handle == NULL || handle == RTLD_SELF) {
2590 retaddr = __builtin_return_address(0); /* __GNUC__ only */
2591 if ((obj = obj_from_addr(retaddr)) == NULL)
2592 _rtld_error("Cannot determine caller's shared object");
2594 obj = dlcheck(handle);
2597 lock_release(rtld_bind_lock, &lockstate);
2603 case RTLD_DI_LINKMAP:
2604 *((struct link_map const **)p) = &obj->linkmap;
2606 case RTLD_DI_ORIGIN:
2607 error = rtld_dirname(obj->path, p);
2610 case RTLD_DI_SERINFOSIZE:
2611 case RTLD_DI_SERINFO:
2612 error = do_search_info(obj, request, (struct dl_serinfo *)p);
2616 _rtld_error("Invalid request %d passed to dlinfo()", request);
2620 lock_release(rtld_bind_lock, &lockstate);
2626 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
2629 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
2630 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
2631 STAILQ_FIRST(&obj->names)->name : obj->path;
2632 phdr_info->dlpi_phdr = obj->phdr;
2633 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
2634 phdr_info->dlpi_tls_modid = obj->tlsindex;
2635 phdr_info->dlpi_tls_data = obj->tlsinit;
2636 phdr_info->dlpi_adds = obj_loads;
2637 phdr_info->dlpi_subs = obj_loads - obj_count;
2641 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
2643 struct dl_phdr_info phdr_info;
2644 const Obj_Entry *obj;
2645 RtldLockState bind_lockstate, phdr_lockstate;
2648 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
2649 rlock_acquire(rtld_bind_lock, &bind_lockstate);
2653 for (obj = obj_list; obj != NULL; obj = obj->next) {
2654 rtld_fill_dl_phdr_info(obj, &phdr_info);
2655 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
2659 lock_release(rtld_bind_lock, &bind_lockstate);
2660 lock_release(rtld_phdr_lock, &phdr_lockstate);
2665 struct fill_search_info_args {
2668 Dl_serinfo *serinfo;
2669 Dl_serpath *serpath;
2674 fill_search_info(const char *dir, size_t dirlen, void *param)
2676 struct fill_search_info_args *arg;
2680 if (arg->request == RTLD_DI_SERINFOSIZE) {
2681 arg->serinfo->dls_cnt ++;
2682 arg->serinfo->dls_size += sizeof(Dl_serpath) + dirlen + 1;
2684 struct dl_serpath *s_entry;
2686 s_entry = arg->serpath;
2687 s_entry->dls_name = arg->strspace;
2688 s_entry->dls_flags = arg->flags;
2690 strncpy(arg->strspace, dir, dirlen);
2691 arg->strspace[dirlen] = '\0';
2693 arg->strspace += dirlen + 1;
2701 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2703 struct dl_serinfo _info;
2704 struct fill_search_info_args args;
2706 args.request = RTLD_DI_SERINFOSIZE;
2707 args.serinfo = &_info;
2709 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2712 path_enumerate(ld_library_path, fill_search_info, &args);
2713 path_enumerate(obj->rpath, fill_search_info, &args);
2714 path_enumerate(gethints(), fill_search_info, &args);
2715 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
2718 if (request == RTLD_DI_SERINFOSIZE) {
2719 info->dls_size = _info.dls_size;
2720 info->dls_cnt = _info.dls_cnt;
2724 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
2725 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
2729 args.request = RTLD_DI_SERINFO;
2730 args.serinfo = info;
2731 args.serpath = &info->dls_serpath[0];
2732 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
2734 args.flags = LA_SER_LIBPATH;
2735 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
2738 args.flags = LA_SER_RUNPATH;
2739 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
2742 args.flags = LA_SER_CONFIG;
2743 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
2746 args.flags = LA_SER_DEFAULT;
2747 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
2753 rtld_dirname(const char *path, char *bname)
2757 /* Empty or NULL string gets treated as "." */
2758 if (path == NULL || *path == '\0') {
2764 /* Strip trailing slashes */
2765 endp = path + strlen(path) - 1;
2766 while (endp > path && *endp == '/')
2769 /* Find the start of the dir */
2770 while (endp > path && *endp != '/')
2773 /* Either the dir is "/" or there are no slashes */
2775 bname[0] = *endp == '/' ? '/' : '.';
2781 } while (endp > path && *endp == '/');
2784 if (endp - path + 2 > PATH_MAX)
2786 _rtld_error("Filename is too long: %s", path);
2790 strncpy(bname, path, endp - path + 1);
2791 bname[endp - path + 1] = '\0';
2796 rtld_dirname_abs(const char *path, char *base)
2798 char base_rel[PATH_MAX];
2800 if (rtld_dirname(path, base) == -1)
2804 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
2805 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
2806 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
2808 strcpy(base, base_rel);
2813 linkmap_add(Obj_Entry *obj)
2815 struct link_map *l = &obj->linkmap;
2816 struct link_map *prev;
2818 obj->linkmap.l_name = obj->path;
2819 obj->linkmap.l_addr = obj->mapbase;
2820 obj->linkmap.l_ld = obj->dynamic;
2822 /* GDB needs load offset on MIPS to use the symbols */
2823 obj->linkmap.l_offs = obj->relocbase;
2826 if (r_debug.r_map == NULL) {
2832 * Scan to the end of the list, but not past the entry for the
2833 * dynamic linker, which we want to keep at the very end.
2835 for (prev = r_debug.r_map;
2836 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
2837 prev = prev->l_next)
2840 /* Link in the new entry. */
2842 l->l_next = prev->l_next;
2843 if (l->l_next != NULL)
2844 l->l_next->l_prev = l;
2849 linkmap_delete(Obj_Entry *obj)
2851 struct link_map *l = &obj->linkmap;
2853 if (l->l_prev == NULL) {
2854 if ((r_debug.r_map = l->l_next) != NULL)
2855 l->l_next->l_prev = NULL;
2859 if ((l->l_prev->l_next = l->l_next) != NULL)
2860 l->l_next->l_prev = l->l_prev;
2864 * Function for the debugger to set a breakpoint on to gain control.
2866 * The two parameters allow the debugger to easily find and determine
2867 * what the runtime loader is doing and to whom it is doing it.
2869 * When the loadhook trap is hit (r_debug_state, set at program
2870 * initialization), the arguments can be found on the stack:
2872 * +8 struct link_map *m
2873 * +4 struct r_debug *rd
2877 r_debug_state(struct r_debug* rd, struct link_map *m)
2880 * The following is a hack to force the compiler to emit calls to
2881 * this function, even when optimizing. If the function is empty,
2882 * the compiler is not obliged to emit any code for calls to it,
2883 * even when marked __noinline. However, gdb depends on those
2886 __asm __volatile("" : : : "memory");
2890 * Get address of the pointer variable in the main program.
2891 * Prefer non-weak symbol over the weak one.
2893 static const void **
2894 get_program_var_addr(const char *name, RtldLockState *lockstate)
2899 symlook_init(&req, name);
2900 req.lockstate = lockstate;
2901 donelist_init(&donelist);
2902 if (symlook_global(&req, &donelist) != 0)
2904 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
2905 return ((const void **)make_function_pointer(req.sym_out,
2907 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
2908 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
2910 return ((const void **)(req.defobj_out->relocbase +
2911 req.sym_out->st_value));
2915 * Set a pointer variable in the main program to the given value. This
2916 * is used to set key variables such as "environ" before any of the
2917 * init functions are called.
2920 set_program_var(const char *name, const void *value)
2924 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
2925 dbg("\"%s\": *%p <-- %p", name, addr, value);
2931 * Search the global objects, including dependencies and main object,
2932 * for the given symbol.
2935 symlook_global(SymLook *req, DoneList *donelist)
2938 const Objlist_Entry *elm;
2941 symlook_init_from_req(&req1, req);
2943 /* Search all objects loaded at program start up. */
2944 if (req->defobj_out == NULL ||
2945 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
2946 res = symlook_list(&req1, &list_main, donelist);
2947 if (res == 0 && (req->defobj_out == NULL ||
2948 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
2949 req->sym_out = req1.sym_out;
2950 req->defobj_out = req1.defobj_out;
2951 assert(req->defobj_out != NULL);
2955 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
2956 STAILQ_FOREACH(elm, &list_global, link) {
2957 if (req->defobj_out != NULL &&
2958 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
2960 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
2961 if (res == 0 && (req->defobj_out == NULL ||
2962 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
2963 req->sym_out = req1.sym_out;
2964 req->defobj_out = req1.defobj_out;
2965 assert(req->defobj_out != NULL);
2969 return (req->sym_out != NULL ? 0 : ESRCH);
2973 * Given a symbol name in a referencing object, find the corresponding
2974 * definition of the symbol. Returns a pointer to the symbol, or NULL if
2975 * no definition was found. Returns a pointer to the Obj_Entry of the
2976 * defining object via the reference parameter DEFOBJ_OUT.
2979 symlook_default(SymLook *req, const Obj_Entry *refobj)
2982 const Objlist_Entry *elm;
2986 donelist_init(&donelist);
2987 symlook_init_from_req(&req1, req);
2989 /* Look first in the referencing object if linked symbolically. */
2990 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
2991 res = symlook_obj(&req1, refobj);
2993 req->sym_out = req1.sym_out;
2994 req->defobj_out = req1.defobj_out;
2995 assert(req->defobj_out != NULL);
2999 symlook_global(req, &donelist);
3001 /* Search all dlopened DAGs containing the referencing object. */
3002 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3003 if (req->sym_out != NULL &&
3004 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3006 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3007 if (res == 0 && (req->sym_out == NULL ||
3008 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3009 req->sym_out = req1.sym_out;
3010 req->defobj_out = req1.defobj_out;
3011 assert(req->defobj_out != NULL);
3016 * Search the dynamic linker itself, and possibly resolve the
3017 * symbol from there. This is how the application links to
3018 * dynamic linker services such as dlopen.
3020 if (req->sym_out == NULL ||
3021 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3022 res = symlook_obj(&req1, &obj_rtld);
3024 req->sym_out = req1.sym_out;
3025 req->defobj_out = req1.defobj_out;
3026 assert(req->defobj_out != NULL);
3030 return (req->sym_out != NULL ? 0 : ESRCH);
3034 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3037 const Obj_Entry *defobj;
3038 const Objlist_Entry *elm;
3044 STAILQ_FOREACH(elm, objlist, link) {
3045 if (donelist_check(dlp, elm->obj))
3047 symlook_init_from_req(&req1, req);
3048 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3049 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3051 defobj = req1.defobj_out;
3052 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3059 req->defobj_out = defobj;
3066 * Search the chain of DAGS cointed to by the given Needed_Entry
3067 * for a symbol of the given name. Each DAG is scanned completely
3068 * before advancing to the next one. Returns a pointer to the symbol,
3069 * or NULL if no definition was found.
3072 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3075 const Needed_Entry *n;
3076 const Obj_Entry *defobj;
3082 symlook_init_from_req(&req1, req);
3083 for (n = needed; n != NULL; n = n->next) {
3084 if (n->obj == NULL ||
3085 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3087 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3089 defobj = req1.defobj_out;
3090 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3096 req->defobj_out = defobj;
3103 * Search the symbol table of a single shared object for a symbol of
3104 * the given name and version, if requested. Returns a pointer to the
3105 * symbol, or NULL if no definition was found. If the object is
3106 * filter, return filtered symbol from filtee.
3108 * The symbol's hash value is passed in for efficiency reasons; that
3109 * eliminates many recomputations of the hash value.
3112 symlook_obj(SymLook *req, const Obj_Entry *obj)
3118 mres = symlook_obj1(req, obj);
3120 if (obj->needed_filtees != NULL) {
3121 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3122 donelist_init(&donelist);
3123 symlook_init_from_req(&req1, req);
3124 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3126 req->sym_out = req1.sym_out;
3127 req->defobj_out = req1.defobj_out;
3131 if (obj->needed_aux_filtees != NULL) {
3132 load_filtees(__DECONST(Obj_Entry *, obj), 0, req->lockstate);
3133 donelist_init(&donelist);
3134 symlook_init_from_req(&req1, req);
3135 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3137 req->sym_out = req1.sym_out;
3138 req->defobj_out = req1.defobj_out;
3147 symlook_obj1(SymLook *req, const Obj_Entry *obj)
3149 unsigned long symnum;
3150 const Elf_Sym *vsymp;
3154 if (obj->buckets == NULL)
3159 symnum = obj->buckets[req->hash % obj->nbuckets];
3161 for (; symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
3162 const Elf_Sym *symp;
3165 if (symnum >= obj->nchains)
3166 return (ESRCH); /* Bad object */
3168 symp = obj->symtab + symnum;
3169 strp = obj->strtab + symp->st_name;
3171 switch (ELF_ST_TYPE(symp->st_info)) {
3176 if (symp->st_value == 0)
3180 if (symp->st_shndx != SHN_UNDEF)
3183 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3184 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3191 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
3194 if (req->ventry == NULL) {
3195 if (obj->versyms != NULL) {
3196 verndx = VER_NDX(obj->versyms[symnum]);
3197 if (verndx > obj->vernum) {
3198 _rtld_error("%s: symbol %s references wrong version %d",
3199 obj->path, obj->strtab + symnum, verndx);
3203 * If we are not called from dlsym (i.e. this is a normal
3204 * relocation from unversioned binary), accept the symbol
3205 * immediately if it happens to have first version after
3206 * this shared object became versioned. Otherwise, if
3207 * symbol is versioned and not hidden, remember it. If it
3208 * is the only symbol with this name exported by the
3209 * shared object, it will be returned as a match at the
3210 * end of the function. If symbol is global (verndx < 2)
3211 * accept it unconditionally.
3213 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3214 verndx == VER_NDX_GIVEN) {
3215 req->sym_out = symp;
3216 req->defobj_out = obj;
3219 else if (verndx >= VER_NDX_GIVEN) {
3220 if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) {
3228 req->sym_out = symp;
3229 req->defobj_out = obj;
3232 if (obj->versyms == NULL) {
3233 if (object_match_name(obj, req->ventry->name)) {
3234 _rtld_error("%s: object %s should provide version %s for "
3235 "symbol %s", obj_rtld.path, obj->path,
3236 req->ventry->name, obj->strtab + symnum);
3240 verndx = VER_NDX(obj->versyms[symnum]);
3241 if (verndx > obj->vernum) {
3242 _rtld_error("%s: symbol %s references wrong version %d",
3243 obj->path, obj->strtab + symnum, verndx);
3246 if (obj->vertab[verndx].hash != req->ventry->hash ||
3247 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3249 * Version does not match. Look if this is a global symbol
3250 * and if it is not hidden. If global symbol (verndx < 2)
3251 * is available, use it. Do not return symbol if we are
3252 * called by dlvsym, because dlvsym looks for a specific
3253 * version and default one is not what dlvsym wants.
3255 if ((req->flags & SYMLOOK_DLSYM) ||
3256 (obj->versyms[symnum] & VER_NDX_HIDDEN) ||
3257 (verndx >= VER_NDX_GIVEN))
3261 req->sym_out = symp;
3262 req->defobj_out = obj;
3267 req->sym_out = vsymp;
3268 req->defobj_out = obj;
3275 trace_loaded_objects(Obj_Entry *obj)
3277 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
3280 if ((main_local = getenv(LD_ "TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
3283 if ((fmt1 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT1")) == NULL)
3284 fmt1 = "\t%o => %p (%x)\n";
3286 if ((fmt2 = getenv(LD_ "TRACE_LOADED_OBJECTS_FMT2")) == NULL)
3287 fmt2 = "\t%o (%x)\n";
3289 list_containers = getenv(LD_ "TRACE_LOADED_OBJECTS_ALL");
3291 for (; obj; obj = obj->next) {
3292 Needed_Entry *needed;
3296 if (list_containers && obj->needed != NULL)
3297 rtld_printf("%s:\n", obj->path);
3298 for (needed = obj->needed; needed; needed = needed->next) {
3299 if (needed->obj != NULL) {
3300 if (needed->obj->traced && !list_containers)
3302 needed->obj->traced = true;
3303 path = needed->obj->path;
3307 name = (char *)obj->strtab + needed->name;
3308 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
3310 fmt = is_lib ? fmt1 : fmt2;
3311 while ((c = *fmt++) != '\0') {
3337 rtld_putstr(main_local);
3340 rtld_putstr(obj_main->path);
3347 rtld_printf("%d", sodp->sod_major);
3350 rtld_printf("%d", sodp->sod_minor);
3357 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
3370 * Unload a dlopened object and its dependencies from memory and from
3371 * our data structures. It is assumed that the DAG rooted in the
3372 * object has already been unreferenced, and that the object has a
3373 * reference count of 0.
3376 unload_object(Obj_Entry *root)
3381 assert(root->refcount == 0);
3384 * Pass over the DAG removing unreferenced objects from
3385 * appropriate lists.
3387 unlink_object(root);
3389 /* Unmap all objects that are no longer referenced. */
3390 linkp = &obj_list->next;
3391 while ((obj = *linkp) != NULL) {
3392 if (obj->refcount == 0) {
3393 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
3395 dbg("unloading \"%s\"", obj->path);
3396 unload_filtees(root);
3397 munmap(obj->mapbase, obj->mapsize);
3398 linkmap_delete(obj);
3409 unlink_object(Obj_Entry *root)
3413 if (root->refcount == 0) {
3414 /* Remove the object from the RTLD_GLOBAL list. */
3415 objlist_remove(&list_global, root);
3417 /* Remove the object from all objects' DAG lists. */
3418 STAILQ_FOREACH(elm, &root->dagmembers, link) {
3419 objlist_remove(&elm->obj->dldags, root);
3420 if (elm->obj != root)
3421 unlink_object(elm->obj);
3427 ref_dag(Obj_Entry *root)
3431 assert(root->dag_inited);
3432 STAILQ_FOREACH(elm, &root->dagmembers, link)
3433 elm->obj->refcount++;
3437 unref_dag(Obj_Entry *root)
3441 assert(root->dag_inited);
3442 STAILQ_FOREACH(elm, &root->dagmembers, link)
3443 elm->obj->refcount--;
3447 * Common code for MD __tls_get_addr().
3450 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
3452 Elf_Addr* dtv = *dtvp;
3453 RtldLockState lockstate;
3455 /* Check dtv generation in case new modules have arrived */
3456 if (dtv[0] != tls_dtv_generation) {
3460 wlock_acquire(rtld_bind_lock, &lockstate);
3461 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3463 if (to_copy > tls_max_index)
3464 to_copy = tls_max_index;
3465 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
3466 newdtv[0] = tls_dtv_generation;
3467 newdtv[1] = tls_max_index;
3469 lock_release(rtld_bind_lock, &lockstate);
3470 dtv = *dtvp = newdtv;
3473 /* Dynamically allocate module TLS if necessary */
3474 if (!dtv[index + 1]) {
3475 /* Signal safe, wlock will block out signals. */
3476 wlock_acquire(rtld_bind_lock, &lockstate);
3477 if (!dtv[index + 1])
3478 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
3479 lock_release(rtld_bind_lock, &lockstate);
3481 return (void*) (dtv[index + 1] + offset);
3484 /* XXX not sure what variants to use for arm. */
3486 #if defined(__ia64__) || defined(__powerpc__)
3489 * Allocate Static TLS using the Variant I method.
3492 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
3501 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
3504 assert(tcbsize >= TLS_TCB_SIZE);
3505 tcb = calloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
3506 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
3508 if (oldtcb != NULL) {
3509 memcpy(tls, oldtcb, tls_static_space);
3512 /* Adjust the DTV. */
3514 for (i = 0; i < dtv[1]; i++) {
3515 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
3516 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
3517 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
3521 dtv = calloc(tls_max_index + 2, sizeof(Elf_Addr));
3523 dtv[0] = tls_dtv_generation;
3524 dtv[1] = tls_max_index;
3526 for (obj = objs; obj; obj = obj->next) {
3527 if (obj->tlsoffset > 0) {
3528 addr = (Elf_Addr)tls + obj->tlsoffset;
3529 if (obj->tlsinitsize > 0)
3530 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3531 if (obj->tlssize > obj->tlsinitsize)
3532 memset((void*) (addr + obj->tlsinitsize), 0,
3533 obj->tlssize - obj->tlsinitsize);
3534 dtv[obj->tlsindex + 1] = addr;
3543 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
3546 Elf_Addr tlsstart, tlsend;
3549 assert(tcbsize >= TLS_TCB_SIZE);
3551 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
3552 tlsend = tlsstart + tls_static_space;
3554 dtv = *(Elf_Addr **)tlsstart;
3556 for (i = 0; i < dtvsize; i++) {
3557 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
3558 free((void*)dtv[i+2]);
3567 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) || \
3568 defined(__arm__) || defined(__mips__)
3571 * Allocate Static TLS using the Variant II method.
3574 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
3579 Elf_Addr *dtv, *olddtv;
3580 Elf_Addr segbase, oldsegbase, addr;
3583 size = round(tls_static_space, tcbalign);
3585 assert(tcbsize >= 2*sizeof(Elf_Addr));
3586 tls = calloc(1, size + tcbsize);
3587 dtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
3589 segbase = (Elf_Addr)(tls + size);
3590 ((Elf_Addr*)segbase)[0] = segbase;
3591 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
3593 dtv[0] = tls_dtv_generation;
3594 dtv[1] = tls_max_index;
3598 * Copy the static TLS block over whole.
3600 oldsegbase = (Elf_Addr) oldtls;
3601 memcpy((void *)(segbase - tls_static_space),
3602 (const void *)(oldsegbase - tls_static_space),
3606 * If any dynamic TLS blocks have been created tls_get_addr(),
3609 olddtv = ((Elf_Addr**)oldsegbase)[1];
3610 for (i = 0; i < olddtv[1]; i++) {
3611 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
3612 dtv[i+2] = olddtv[i+2];
3618 * We assume that this block was the one we created with
3619 * allocate_initial_tls().
3621 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
3623 for (obj = objs; obj; obj = obj->next) {
3624 if (obj->tlsoffset) {
3625 addr = segbase - obj->tlsoffset;
3626 memset((void*) (addr + obj->tlsinitsize),
3627 0, obj->tlssize - obj->tlsinitsize);
3629 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
3630 dtv[obj->tlsindex + 1] = addr;
3635 return (void*) segbase;
3639 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
3644 Elf_Addr tlsstart, tlsend;
3647 * Figure out the size of the initial TLS block so that we can
3648 * find stuff which ___tls_get_addr() allocated dynamically.
3650 size = round(tls_static_space, tcbalign);
3652 dtv = ((Elf_Addr**)tls)[1];
3654 tlsend = (Elf_Addr) tls;
3655 tlsstart = tlsend - size;
3656 for (i = 0; i < dtvsize; i++) {
3657 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
3658 free((void*) dtv[i+2]);
3662 free((void*) tlsstart);
3669 * Allocate TLS block for module with given index.
3672 allocate_module_tls(int index)
3677 for (obj = obj_list; obj; obj = obj->next) {
3678 if (obj->tlsindex == index)
3682 _rtld_error("Can't find module with TLS index %d", index);
3686 p = malloc(obj->tlssize);
3688 _rtld_error("Cannot allocate TLS block for index %d", index);
3691 memcpy(p, obj->tlsinit, obj->tlsinitsize);
3692 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
3698 allocate_tls_offset(Obj_Entry *obj)
3705 if (obj->tlssize == 0) {
3706 obj->tls_done = true;
3710 if (obj->tlsindex == 1)
3711 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
3713 off = calculate_tls_offset(tls_last_offset, tls_last_size,
3714 obj->tlssize, obj->tlsalign);
3717 * If we have already fixed the size of the static TLS block, we
3718 * must stay within that size. When allocating the static TLS, we
3719 * leave a small amount of space spare to be used for dynamically
3720 * loading modules which use static TLS.
3722 if (tls_static_space) {
3723 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
3727 tls_last_offset = obj->tlsoffset = off;
3728 tls_last_size = obj->tlssize;
3729 obj->tls_done = true;
3735 free_tls_offset(Obj_Entry *obj)
3739 * If we were the last thing to allocate out of the static TLS
3740 * block, we give our space back to the 'allocator'. This is a
3741 * simplistic workaround to allow libGL.so.1 to be loaded and
3742 * unloaded multiple times.
3744 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
3745 == calculate_tls_end(tls_last_offset, tls_last_size)) {
3746 tls_last_offset -= obj->tlssize;
3752 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
3755 RtldLockState lockstate;
3757 wlock_acquire(rtld_bind_lock, &lockstate);
3758 ret = allocate_tls(obj_list, oldtls, tcbsize, tcbalign);
3759 lock_release(rtld_bind_lock, &lockstate);
3764 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
3766 RtldLockState lockstate;
3768 wlock_acquire(rtld_bind_lock, &lockstate);
3769 free_tls(tcb, tcbsize, tcbalign);
3770 lock_release(rtld_bind_lock, &lockstate);
3774 object_add_name(Obj_Entry *obj, const char *name)
3780 entry = malloc(sizeof(Name_Entry) + len);
3782 if (entry != NULL) {
3783 strcpy(entry->name, name);
3784 STAILQ_INSERT_TAIL(&obj->names, entry, link);
3789 object_match_name(const Obj_Entry *obj, const char *name)
3793 STAILQ_FOREACH(entry, &obj->names, link) {
3794 if (strcmp(name, entry->name) == 0)
3801 locate_dependency(const Obj_Entry *obj, const char *name)
3803 const Objlist_Entry *entry;
3804 const Needed_Entry *needed;
3806 STAILQ_FOREACH(entry, &list_main, link) {
3807 if (object_match_name(entry->obj, name))
3811 for (needed = obj->needed; needed != NULL; needed = needed->next) {
3812 if (strcmp(obj->strtab + needed->name, name) == 0 ||
3813 (needed->obj != NULL && object_match_name(needed->obj, name))) {
3815 * If there is DT_NEEDED for the name we are looking for,
3816 * we are all set. Note that object might not be found if
3817 * dependency was not loaded yet, so the function can
3818 * return NULL here. This is expected and handled
3819 * properly by the caller.
3821 return (needed->obj);
3824 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
3830 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
3831 const Elf_Vernaux *vna)
3833 const Elf_Verdef *vd;
3834 const char *vername;
3836 vername = refobj->strtab + vna->vna_name;
3837 vd = depobj->verdef;
3839 _rtld_error("%s: version %s required by %s not defined",
3840 depobj->path, vername, refobj->path);
3844 if (vd->vd_version != VER_DEF_CURRENT) {
3845 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3846 depobj->path, vd->vd_version);
3849 if (vna->vna_hash == vd->vd_hash) {
3850 const Elf_Verdaux *aux = (const Elf_Verdaux *)
3851 ((char *)vd + vd->vd_aux);
3852 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
3855 if (vd->vd_next == 0)
3857 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3859 if (vna->vna_flags & VER_FLG_WEAK)
3861 _rtld_error("%s: version %s required by %s not found",
3862 depobj->path, vername, refobj->path);
3867 rtld_verify_object_versions(Obj_Entry *obj)
3869 const Elf_Verneed *vn;
3870 const Elf_Verdef *vd;
3871 const Elf_Verdaux *vda;
3872 const Elf_Vernaux *vna;
3873 const Obj_Entry *depobj;
3874 int maxvernum, vernum;
3878 * Walk over defined and required version records and figure out
3879 * max index used by any of them. Do very basic sanity checking
3883 while (vn != NULL) {
3884 if (vn->vn_version != VER_NEED_CURRENT) {
3885 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
3886 obj->path, vn->vn_version);
3889 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3891 vernum = VER_NEED_IDX(vna->vna_other);
3892 if (vernum > maxvernum)
3894 if (vna->vna_next == 0)
3896 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3898 if (vn->vn_next == 0)
3900 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3904 while (vd != NULL) {
3905 if (vd->vd_version != VER_DEF_CURRENT) {
3906 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
3907 obj->path, vd->vd_version);
3910 vernum = VER_DEF_IDX(vd->vd_ndx);
3911 if (vernum > maxvernum)
3913 if (vd->vd_next == 0)
3915 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3922 * Store version information in array indexable by version index.
3923 * Verify that object version requirements are satisfied along the
3926 obj->vernum = maxvernum + 1;
3927 obj->vertab = calloc(obj->vernum, sizeof(Ver_Entry));
3930 while (vd != NULL) {
3931 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
3932 vernum = VER_DEF_IDX(vd->vd_ndx);
3933 assert(vernum <= maxvernum);
3934 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
3935 obj->vertab[vernum].hash = vd->vd_hash;
3936 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
3937 obj->vertab[vernum].file = NULL;
3938 obj->vertab[vernum].flags = 0;
3940 if (vd->vd_next == 0)
3942 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
3946 while (vn != NULL) {
3947 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
3950 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
3952 if (check_object_provided_version(obj, depobj, vna))
3954 vernum = VER_NEED_IDX(vna->vna_other);
3955 assert(vernum <= maxvernum);
3956 obj->vertab[vernum].hash = vna->vna_hash;
3957 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
3958 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
3959 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
3960 VER_INFO_HIDDEN : 0;
3961 if (vna->vna_next == 0)
3963 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
3965 if (vn->vn_next == 0)
3967 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
3973 rtld_verify_versions(const Objlist *objlist)
3975 Objlist_Entry *entry;
3979 STAILQ_FOREACH(entry, objlist, link) {
3981 * Skip dummy objects or objects that have their version requirements
3984 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
3986 if (rtld_verify_object_versions(entry->obj) == -1) {
3988 if (ld_tracing == NULL)
3992 if (rc == 0 || ld_tracing != NULL)
3993 rc = rtld_verify_object_versions(&obj_rtld);
3998 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4003 vernum = VER_NDX(obj->versyms[symnum]);
4004 if (vernum >= obj->vernum) {
4005 _rtld_error("%s: symbol %s has wrong verneed value %d",
4006 obj->path, obj->strtab + symnum, vernum);
4007 } else if (obj->vertab[vernum].hash != 0) {
4008 return &obj->vertab[vernum];
4015 _rtld_get_stack_prot(void)
4018 return (stack_prot);
4022 map_stacks_exec(RtldLockState *lockstate)
4024 void (*thr_map_stacks_exec)(void);
4026 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4028 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4029 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4030 if (thr_map_stacks_exec != NULL) {
4031 stack_prot |= PROT_EXEC;
4032 thr_map_stacks_exec();
4037 symlook_init(SymLook *dst, const char *name)
4040 bzero(dst, sizeof(*dst));
4042 dst->hash = elf_hash(name);
4046 symlook_init_from_req(SymLook *dst, const SymLook *src)
4049 dst->name = src->name;
4050 dst->hash = src->hash;
4051 dst->ventry = src->ventry;
4052 dst->flags = src->flags;
4053 dst->defobj_out = NULL;
4054 dst->sym_out = NULL;
4055 dst->lockstate = src->lockstate;
4059 * Overrides for libc_pic-provided functions.
4063 __getosreldate(void)
4073 oid[1] = KERN_OSRELDATE;
4075 len = sizeof(osrel);
4076 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4077 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4083 * No unresolved symbols for rtld.
4086 __pthread_cxa_finalize(struct dl_phdr_info *a)