2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
6 * Copyright 2014-2017 The FreeBSD Foundation
9 * Portions of this software were developed by Konstantin Belousov
10 * under sponsorship from the FreeBSD Foundation.
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 * Dynamic linker for ELF.
36 * John Polstra <jdp@polstra.com>.
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
42 #include <sys/param.h>
43 #include <sys/mount.h>
46 #include <sys/sysctl.h>
48 #include <sys/utsname.h>
49 #include <sys/ktrace.h>
66 #include "rtld_printf.h"
67 #include "rtld_utrace.h"
71 typedef void (*func_ptr_type)();
72 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
75 * Function declarations.
77 static const char *basename(const char *);
78 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
79 const Elf_Dyn **, const Elf_Dyn **);
80 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
82 static void digest_dynamic(Obj_Entry *, int);
83 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
84 static Obj_Entry *dlcheck(void *);
85 static int dlclose_locked(void *, RtldLockState *);
86 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
87 int lo_flags, int mode, RtldLockState *lockstate);
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 *, int *);
95 static const char *gethints(bool);
96 static void hold_object(Obj_Entry *);
97 static void unhold_object(Obj_Entry *);
98 static void init_dag(Obj_Entry *);
99 static void init_marker(Obj_Entry *);
100 static void init_pagesizes(Elf_Auxinfo **aux_info);
101 static void init_rtld(caddr_t, Elf_Auxinfo **);
102 static void initlist_add_neededs(Needed_Entry *, Objlist *);
103 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
104 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
105 static void linkmap_add(Obj_Entry *);
106 static void linkmap_delete(Obj_Entry *);
107 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
108 static void unload_filtees(Obj_Entry *, RtldLockState *);
109 static int load_needed_objects(Obj_Entry *, int);
110 static int load_preload_objects(void);
111 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
112 static void map_stacks_exec(RtldLockState *);
113 static int obj_disable_relro(Obj_Entry *);
114 static int obj_enforce_relro(Obj_Entry *);
115 static Obj_Entry *obj_from_addr(const void *);
116 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
117 static void objlist_call_init(Objlist *, RtldLockState *);
118 static void objlist_clear(Objlist *);
119 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
120 static void objlist_init(Objlist *);
121 static void objlist_push_head(Objlist *, Obj_Entry *);
122 static void objlist_push_tail(Objlist *, Obj_Entry *);
123 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
124 static void objlist_remove(Objlist *, Obj_Entry *);
125 static int open_binary_fd(const char *argv0, bool search_in_path);
126 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp);
127 static int parse_integer(const char *);
128 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
129 static void print_usage(const char *argv0);
130 static void release_object(Obj_Entry *);
131 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
132 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
133 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
134 int flags, RtldLockState *lockstate);
135 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
137 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
138 static int rtld_dirname(const char *, char *);
139 static int rtld_dirname_abs(const char *, char *);
140 static void *rtld_dlopen(const char *name, int fd, int mode);
141 static void rtld_exit(void);
142 static char *search_library_path(const char *, const char *, const char *,
144 static char *search_library_pathfds(const char *, const char *, int *);
145 static const void **get_program_var_addr(const char *, RtldLockState *);
146 static void set_program_var(const char *, const void *);
147 static int symlook_default(SymLook *, const Obj_Entry *refobj);
148 static int symlook_global(SymLook *, DoneList *);
149 static void symlook_init_from_req(SymLook *, const SymLook *);
150 static int symlook_list(SymLook *, const Objlist *, DoneList *);
151 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
152 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
153 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
154 static void trace_loaded_objects(Obj_Entry *);
155 static void unlink_object(Obj_Entry *);
156 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
157 static void unref_dag(Obj_Entry *);
158 static void ref_dag(Obj_Entry *);
159 static char *origin_subst_one(Obj_Entry *, char *, const char *,
161 static char *origin_subst(Obj_Entry *, char *);
162 static bool obj_resolve_origin(Obj_Entry *obj);
163 static void preinit_main(void);
164 static int rtld_verify_versions(const Objlist *);
165 static int rtld_verify_object_versions(Obj_Entry *);
166 static void object_add_name(Obj_Entry *, const char *);
167 static int object_match_name(const Obj_Entry *, const char *);
168 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
169 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
170 struct dl_phdr_info *phdr_info);
171 static uint32_t gnu_hash(const char *);
172 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
173 const unsigned long);
175 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
176 void _r_debug_postinit(struct link_map *) __noinline __exported;
178 int __sys_openat(int, const char *, int, ...);
183 static char *error_message; /* Message for dlerror(), or NULL */
184 struct r_debug r_debug __exported; /* for GDB; */
185 static bool libmap_disable; /* Disable libmap */
186 static bool ld_loadfltr; /* Immediate filters processing */
187 static char *libmap_override; /* Maps to use in addition to libmap.conf */
188 static bool trust; /* False for setuid and setgid programs */
189 static bool dangerous_ld_env; /* True if environment variables have been
190 used to affect the libraries loaded */
191 bool ld_bind_not; /* Disable PLT update */
192 static char *ld_bind_now; /* Environment variable for immediate binding */
193 static char *ld_debug; /* Environment variable for debugging */
194 static char *ld_library_path; /* Environment variable for search path */
195 static char *ld_library_dirs; /* Environment variable for library descriptors */
196 static char *ld_preload; /* Environment variable for libraries to
198 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
199 static char *ld_tracing; /* Called from ldd to print libs */
200 static char *ld_utrace; /* Use utrace() to log events. */
201 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
202 static Obj_Entry *obj_main; /* The main program shared object */
203 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
204 static unsigned int obj_count; /* Number of objects in obj_list */
205 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
207 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
208 STAILQ_HEAD_INITIALIZER(list_global);
209 static Objlist list_main = /* Objects loaded at program startup */
210 STAILQ_HEAD_INITIALIZER(list_main);
211 static Objlist list_fini = /* Objects needing fini() calls */
212 STAILQ_HEAD_INITIALIZER(list_fini);
214 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
216 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
218 extern Elf_Dyn _DYNAMIC;
219 #pragma weak _DYNAMIC
221 int dlclose(void *) __exported;
222 char *dlerror(void) __exported;
223 void *dlopen(const char *, int) __exported;
224 void *fdlopen(int, int) __exported;
225 void *dlsym(void *, const char *) __exported;
226 dlfunc_t dlfunc(void *, const char *) __exported;
227 void *dlvsym(void *, const char *, const char *) __exported;
228 int dladdr(const void *, Dl_info *) __exported;
229 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
230 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
231 int dlinfo(void *, int , void *) __exported;
232 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
233 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
234 int _rtld_get_stack_prot(void) __exported;
235 int _rtld_is_dlopened(void *) __exported;
236 void _rtld_error(const char *, ...) __exported;
238 int npagesizes, osreldate;
241 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
243 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
244 static int max_stack_flags;
247 * Global declarations normally provided by crt1. The dynamic linker is
248 * not built with crt1, so we have to provide them ourselves.
254 * Used to pass argc, argv to init functions.
260 * Globals to control TLS allocation.
262 size_t tls_last_offset; /* Static TLS offset of last module */
263 size_t tls_last_size; /* Static TLS size of last module */
264 size_t tls_static_space; /* Static TLS space allocated */
265 size_t tls_static_max_align;
266 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
267 int tls_max_index = 1; /* Largest module index allocated */
269 bool ld_library_path_rpath = false;
272 * Globals for path names, and such
274 char *ld_elf_hints_default = _PATH_ELF_HINTS;
275 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
276 char *ld_path_rtld = _PATH_RTLD;
277 char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
278 char *ld_env_prefix = LD_;
281 * Fill in a DoneList with an allocation large enough to hold all of
282 * the currently-loaded objects. Keep this as a macro since it calls
283 * alloca and we want that to occur within the scope of the caller.
285 #define donelist_init(dlp) \
286 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
287 assert((dlp)->objs != NULL), \
288 (dlp)->num_alloc = obj_count, \
291 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
292 if (ld_utrace != NULL) \
293 ld_utrace_log(e, h, mb, ms, r, n); \
297 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
298 int refcnt, const char *name)
300 struct utrace_rtld ut;
301 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
303 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
306 ut.mapbase = mapbase;
307 ut.mapsize = mapsize;
309 bzero(ut.name, sizeof(ut.name));
311 strlcpy(ut.name, name, sizeof(ut.name));
312 utrace(&ut, sizeof(ut));
315 #ifdef RTLD_VARIANT_ENV_NAMES
317 * construct the env variable based on the type of binary that's
320 static inline const char *
323 static char buffer[128];
325 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
326 strlcat(buffer, var, sizeof(buffer));
334 * Main entry point for dynamic linking. The first argument is the
335 * stack pointer. The stack is expected to be laid out as described
336 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
337 * Specifically, the stack pointer points to a word containing
338 * ARGC. Following that in the stack is a null-terminated sequence
339 * of pointers to argument strings. Then comes a null-terminated
340 * sequence of pointers to environment strings. Finally, there is a
341 * sequence of "auxiliary vector" entries.
343 * The second argument points to a place to store the dynamic linker's
344 * exit procedure pointer and the third to a place to store the main
347 * The return value is the main program's entry point.
350 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
352 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
353 Objlist_Entry *entry;
354 Obj_Entry *last_interposer, *obj, *preload_tail;
355 const Elf_Phdr *phdr;
357 RtldLockState lockstate;
360 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath;
362 char buf[MAXPATHLEN];
363 int argc, fd, i, mib[2], phnum, rtld_argc;
365 bool dir_enable, explicit_fd, search_in_path;
368 * On entry, the dynamic linker itself has not been relocated yet.
369 * Be very careful not to reference any global data until after
370 * init_rtld has returned. It is OK to reference file-scope statics
371 * and string constants, and to call static and global functions.
374 /* Find the auxiliary vector on the stack. */
378 sp += argc + 1; /* Skip over arguments and NULL terminator */
380 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
382 aux = (Elf_Auxinfo *) sp;
384 /* Digest the auxiliary vector. */
385 for (i = 0; i < AT_COUNT; i++)
387 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
388 if (auxp->a_type < AT_COUNT)
389 aux_info[auxp->a_type] = auxp;
392 /* Initialize and relocate ourselves. */
393 assert(aux_info[AT_BASE] != NULL);
394 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
396 __progname = obj_rtld.path;
397 argv0 = argv[0] != NULL ? argv[0] : "(null)";
402 if (aux_info[AT_CANARY] != NULL &&
403 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
404 i = aux_info[AT_CANARYLEN]->a_un.a_val;
405 if (i > sizeof(__stack_chk_guard))
406 i = sizeof(__stack_chk_guard);
407 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
412 len = sizeof(__stack_chk_guard);
413 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
414 len != sizeof(__stack_chk_guard)) {
415 /* If sysctl was unsuccessful, use the "terminator canary". */
416 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
417 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
418 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
419 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
423 trust = !issetugid();
425 md_abi_variant_hook(aux_info);
428 if (aux_info[AT_EXECFD] != NULL) {
429 fd = aux_info[AT_EXECFD]->a_un.a_val;
431 assert(aux_info[AT_PHDR] != NULL);
432 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
433 if (phdr == obj_rtld.phdr) {
435 rtld_printf("Tainted process refusing to run binary %s\n",
439 dbg("opening main program in direct exec mode");
441 rtld_argc = parse_args(argv, argc, &search_in_path, &fd);
442 argv0 = argv[rtld_argc];
443 explicit_fd = (fd != -1);
445 fd = open_binary_fd(argv0, search_in_path);
446 if (fstat(fd, &st) == -1) {
447 _rtld_error("failed to fstat FD %d (%s): %s", fd,
448 explicit_fd ? "user-provided descriptor" : argv0,
449 rtld_strerror(errno));
454 * Rough emulation of the permission checks done by
455 * execve(2), only Unix DACs are checked, ACLs are
456 * ignored. Preserve the semantic of disabling owner
457 * to execute if owner x bit is cleared, even if
458 * others x bit is enabled.
459 * mmap(2) does not allow to mmap with PROT_EXEC if
460 * binary' file comes from noexec mount. We cannot
461 * set VV_TEXT on the binary.
464 if (st.st_uid == geteuid()) {
465 if ((st.st_mode & S_IXUSR) != 0)
467 } else if (st.st_gid == getegid()) {
468 if ((st.st_mode & S_IXGRP) != 0)
470 } else if ((st.st_mode & S_IXOTH) != 0) {
474 rtld_printf("No execute permission for binary %s\n",
480 * For direct exec mode, argv[0] is the interpreter
481 * name, we must remove it and shift arguments left
482 * before invoking binary main. Since stack layout
483 * places environment pointers and aux vectors right
484 * after the terminating NULL, we must shift
485 * environment and aux as well.
487 main_argc = argc - rtld_argc;
488 for (i = 0; i <= main_argc; i++)
489 argv[i] = argv[i + rtld_argc];
491 environ = env = envp = argv + main_argc + 1;
493 *envp = *(envp + rtld_argc);
495 } while (*envp != NULL);
496 aux = auxp = (Elf_Auxinfo *)envp;
497 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
498 for (;; auxp++, auxpf++) {
500 if (auxp->a_type == AT_NULL)
504 rtld_printf("no binary\n");
510 ld_bind_now = getenv(_LD("BIND_NOW"));
513 * If the process is tainted, then we un-set the dangerous environment
514 * variables. The process will be marked as tainted until setuid(2)
515 * is called. If any child process calls setuid(2) we do not want any
516 * future processes to honor the potentially un-safe variables.
519 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
520 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
521 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
522 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
523 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
524 _rtld_error("environment corrupt; aborting");
528 ld_debug = getenv(_LD("DEBUG"));
529 if (ld_bind_now == NULL)
530 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
531 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
532 libmap_override = getenv(_LD("LIBMAP"));
533 ld_library_path = getenv(_LD("LIBRARY_PATH"));
534 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
535 ld_preload = getenv(_LD("PRELOAD"));
536 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
537 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
538 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
539 if (library_path_rpath != NULL) {
540 if (library_path_rpath[0] == 'y' ||
541 library_path_rpath[0] == 'Y' ||
542 library_path_rpath[0] == '1')
543 ld_library_path_rpath = true;
545 ld_library_path_rpath = false;
547 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
548 (ld_library_path != NULL) || (ld_preload != NULL) ||
549 (ld_elf_hints_path != NULL) || ld_loadfltr;
550 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
551 ld_utrace = getenv(_LD("UTRACE"));
553 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
554 ld_elf_hints_path = ld_elf_hints_default;
556 if (ld_debug != NULL && *ld_debug != '\0')
558 dbg("%s is initialized, base address = %p", __progname,
559 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
560 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
561 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
563 dbg("initializing thread locks");
567 * Load the main program, or process its program header if it is
570 if (fd != -1) { /* Load the main program. */
571 dbg("loading main program");
572 obj_main = map_object(fd, argv0, NULL);
574 if (obj_main == NULL)
576 max_stack_flags = obj_main->stack_flags;
577 } else { /* Main program already loaded. */
578 dbg("processing main program's program header");
579 assert(aux_info[AT_PHDR] != NULL);
580 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
581 assert(aux_info[AT_PHNUM] != NULL);
582 phnum = aux_info[AT_PHNUM]->a_un.a_val;
583 assert(aux_info[AT_PHENT] != NULL);
584 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
585 assert(aux_info[AT_ENTRY] != NULL);
586 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
587 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
591 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
592 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
593 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
594 if (kexecpath[0] == '/')
595 obj_main->path = kexecpath;
596 else if (getcwd(buf, sizeof(buf)) == NULL ||
597 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
598 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
599 obj_main->path = xstrdup(argv0);
601 obj_main->path = xstrdup(buf);
603 dbg("No AT_EXECPATH or direct exec");
604 obj_main->path = xstrdup(argv0);
606 dbg("obj_main path %s", obj_main->path);
607 obj_main->mainprog = true;
609 if (aux_info[AT_STACKPROT] != NULL &&
610 aux_info[AT_STACKPROT]->a_un.a_val != 0)
611 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
615 * Get the actual dynamic linker pathname from the executable if
616 * possible. (It should always be possible.) That ensures that
617 * gdb will find the right dynamic linker even if a non-standard
620 if (obj_main->interp != NULL &&
621 strcmp(obj_main->interp, obj_rtld.path) != 0) {
623 obj_rtld.path = xstrdup(obj_main->interp);
624 __progname = obj_rtld.path;
628 digest_dynamic(obj_main, 0);
629 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
630 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
631 obj_main->dynsymcount);
633 linkmap_add(obj_main);
634 linkmap_add(&obj_rtld);
636 /* Link the main program into the list of objects. */
637 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
641 /* Initialize a fake symbol for resolving undefined weak references. */
642 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
643 sym_zero.st_shndx = SHN_UNDEF;
644 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
647 libmap_disable = (bool)lm_init(libmap_override);
649 dbg("loading LD_PRELOAD libraries");
650 if (load_preload_objects() == -1)
652 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
654 dbg("loading needed objects");
655 if (load_needed_objects(obj_main, 0) == -1)
658 /* Make a list of all objects loaded at startup. */
659 last_interposer = obj_main;
660 TAILQ_FOREACH(obj, &obj_list, next) {
663 if (obj->z_interpose && obj != obj_main) {
664 objlist_put_after(&list_main, last_interposer, obj);
665 last_interposer = obj;
667 objlist_push_tail(&list_main, obj);
672 dbg("checking for required versions");
673 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
676 if (ld_tracing) { /* We're done */
677 trace_loaded_objects(obj_main);
681 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
682 dump_relocations(obj_main);
687 * Processing tls relocations requires having the tls offsets
688 * initialized. Prepare offsets before starting initial
689 * relocation processing.
691 dbg("initializing initial thread local storage offsets");
692 STAILQ_FOREACH(entry, &list_main, link) {
694 * Allocate all the initial objects out of the static TLS
695 * block even if they didn't ask for it.
697 allocate_tls_offset(entry->obj);
700 if (relocate_objects(obj_main,
701 ld_bind_now != NULL && *ld_bind_now != '\0',
702 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
705 dbg("doing copy relocations");
706 if (do_copy_relocations(obj_main) == -1)
709 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
710 dump_relocations(obj_main);
717 * Setup TLS for main thread. This must be done after the
718 * relocations are processed, since tls initialization section
719 * might be the subject for relocations.
721 dbg("initializing initial thread local storage");
722 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
724 dbg("initializing key program variables");
725 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
726 set_program_var("environ", env);
727 set_program_var("__elf_aux_vector", aux);
729 /* Make a list of init functions to call. */
730 objlist_init(&initlist);
731 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
732 preload_tail, &initlist);
734 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
736 map_stacks_exec(NULL);
738 if (!obj_main->crt_no_init) {
740 * Make sure we don't call the main program's init and fini
741 * functions for binaries linked with old crt1 which calls
744 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
745 obj_main->preinit_array = obj_main->init_array =
746 obj_main->fini_array = (Elf_Addr)NULL;
750 * Execute MD initializers required before we call the objects'
755 wlock_acquire(rtld_bind_lock, &lockstate);
757 dbg("resolving ifuncs");
758 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
759 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
762 if (obj_main->crt_no_init)
764 objlist_call_init(&initlist, &lockstate);
765 _r_debug_postinit(&obj_main->linkmap);
766 objlist_clear(&initlist);
767 dbg("loading filtees");
768 TAILQ_FOREACH(obj, &obj_list, next) {
771 if (ld_loadfltr || obj->z_loadfltr)
772 load_filtees(obj, 0, &lockstate);
775 dbg("enforcing main obj relro");
776 if (obj_enforce_relro(obj_main) == -1)
779 lock_release(rtld_bind_lock, &lockstate);
781 dbg("transferring control to program entry point = %p", obj_main->entry);
783 /* Return the exit procedure and the program entry point. */
784 *exit_proc = rtld_exit;
786 return (func_ptr_type) obj_main->entry;
790 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
795 ptr = (void *)make_function_pointer(def, obj);
796 target = call_ifunc_resolver(ptr);
797 return ((void *)target);
801 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
802 * Changes to this function should be applied there as well.
805 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
809 const Obj_Entry *defobj;
812 RtldLockState lockstate;
814 rlock_acquire(rtld_bind_lock, &lockstate);
815 if (sigsetjmp(lockstate.env, 0) != 0)
816 lock_upgrade(rtld_bind_lock, &lockstate);
818 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
820 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
822 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
823 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
827 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
828 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
830 target = (Elf_Addr)(defobj->relocbase + def->st_value);
832 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
833 defobj->strtab + def->st_name, basename(obj->path),
834 (void *)target, basename(defobj->path));
837 * Write the new contents for the jmpslot. Note that depending on
838 * architecture, the value which we need to return back to the
839 * lazy binding trampoline may or may not be the target
840 * address. The value returned from reloc_jmpslot() is the value
841 * that the trampoline needs.
843 target = reloc_jmpslot(where, target, defobj, obj, rel);
844 lock_release(rtld_bind_lock, &lockstate);
849 * Error reporting function. Use it like printf. If formats the message
850 * into a buffer, and sets things up so that the next call to dlerror()
851 * will return the message.
854 _rtld_error(const char *fmt, ...)
856 static char buf[512];
860 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
866 * Return a dynamically-allocated copy of the current error message, if any.
871 return error_message == NULL ? NULL : xstrdup(error_message);
875 * Restore the current error message from a copy which was previously saved
876 * by errmsg_save(). The copy is freed.
879 errmsg_restore(char *saved_msg)
881 if (saved_msg == NULL)
882 error_message = NULL;
884 _rtld_error("%s", saved_msg);
890 basename(const char *name)
892 const char *p = strrchr(name, '/');
893 return p != NULL ? p + 1 : name;
896 static struct utsname uts;
899 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
900 const char *subst, bool may_free)
902 char *p, *p1, *res, *resp;
903 int subst_len, kw_len, subst_count, old_len, new_len;
908 * First, count the number of the keyword occurrences, to
909 * preallocate the final string.
911 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
918 * If the keyword is not found, just return.
920 * Return non-substituted string if resolution failed. We
921 * cannot do anything more reasonable, the failure mode of the
922 * caller is unresolved library anyway.
924 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
925 return (may_free ? real : xstrdup(real));
927 subst = obj->origin_path;
930 * There is indeed something to substitute. Calculate the
931 * length of the resulting string, and allocate it.
933 subst_len = strlen(subst);
934 old_len = strlen(real);
935 new_len = old_len + (subst_len - kw_len) * subst_count;
936 res = xmalloc(new_len + 1);
939 * Now, execute the substitution loop.
941 for (p = real, resp = res, *resp = '\0';;) {
944 /* Copy the prefix before keyword. */
945 memcpy(resp, p, p1 - p);
947 /* Keyword replacement. */
948 memcpy(resp, subst, subst_len);
956 /* Copy to the end of string and finish. */
964 origin_subst(Obj_Entry *obj, char *real)
966 char *res1, *res2, *res3, *res4;
968 if (obj == NULL || !trust)
969 return (xstrdup(real));
970 if (uts.sysname[0] == '\0') {
971 if (uname(&uts) != 0) {
972 _rtld_error("utsname failed: %d", errno);
976 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
977 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
978 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
979 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
986 const char *msg = dlerror();
990 rtld_fdputstr(STDERR_FILENO, msg);
991 rtld_fdputchar(STDERR_FILENO, '\n');
996 * Process a shared object's DYNAMIC section, and save the important
997 * information in its Obj_Entry structure.
1000 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1001 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1003 const Elf_Dyn *dynp;
1004 Needed_Entry **needed_tail = &obj->needed;
1005 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1006 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1007 const Elf_Hashelt *hashtab;
1008 const Elf32_Word *hashval;
1009 Elf32_Word bkt, nmaskwords;
1011 int plttype = DT_REL;
1015 *dyn_runpath = NULL;
1017 obj->bind_now = false;
1018 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
1019 switch (dynp->d_tag) {
1022 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
1026 obj->relsize = dynp->d_un.d_val;
1030 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1034 obj->pltrel = (const Elf_Rel *)
1035 (obj->relocbase + dynp->d_un.d_ptr);
1039 obj->pltrelsize = dynp->d_un.d_val;
1043 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
1047 obj->relasize = dynp->d_un.d_val;
1051 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1055 plttype = dynp->d_un.d_val;
1056 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1060 obj->symtab = (const Elf_Sym *)
1061 (obj->relocbase + dynp->d_un.d_ptr);
1065 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1069 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
1073 obj->strsize = dynp->d_un.d_val;
1077 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
1082 obj->verneednum = dynp->d_un.d_val;
1086 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1091 obj->verdefnum = dynp->d_un.d_val;
1095 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1101 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1103 obj->nbuckets = hashtab[0];
1104 obj->nchains = hashtab[1];
1105 obj->buckets = hashtab + 2;
1106 obj->chains = obj->buckets + obj->nbuckets;
1107 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1108 obj->buckets != NULL;
1114 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1116 obj->nbuckets_gnu = hashtab[0];
1117 obj->symndx_gnu = hashtab[1];
1118 nmaskwords = hashtab[2];
1119 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1120 obj->maskwords_bm_gnu = nmaskwords - 1;
1121 obj->shift2_gnu = hashtab[3];
1122 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1123 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1124 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1126 /* Number of bitmask words is required to be power of 2 */
1127 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1128 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1134 Needed_Entry *nep = NEW(Needed_Entry);
1135 nep->name = dynp->d_un.d_val;
1140 needed_tail = &nep->next;
1146 Needed_Entry *nep = NEW(Needed_Entry);
1147 nep->name = dynp->d_un.d_val;
1151 *needed_filtees_tail = nep;
1152 needed_filtees_tail = &nep->next;
1158 Needed_Entry *nep = NEW(Needed_Entry);
1159 nep->name = dynp->d_un.d_val;
1163 *needed_aux_filtees_tail = nep;
1164 needed_aux_filtees_tail = &nep->next;
1169 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1173 obj->textrel = true;
1177 obj->symbolic = true;
1182 * We have to wait until later to process this, because we
1183 * might not have gotten the address of the string table yet.
1193 *dyn_runpath = dynp;
1197 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1200 case DT_PREINIT_ARRAY:
1201 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1204 case DT_PREINIT_ARRAYSZ:
1205 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1209 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1212 case DT_INIT_ARRAYSZ:
1213 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1217 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1221 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1224 case DT_FINI_ARRAYSZ:
1225 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1229 * Don't process DT_DEBUG on MIPS as the dynamic section
1230 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1236 dbg("Filling in DT_DEBUG entry");
1237 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1242 if (dynp->d_un.d_val & DF_ORIGIN)
1243 obj->z_origin = true;
1244 if (dynp->d_un.d_val & DF_SYMBOLIC)
1245 obj->symbolic = true;
1246 if (dynp->d_un.d_val & DF_TEXTREL)
1247 obj->textrel = true;
1248 if (dynp->d_un.d_val & DF_BIND_NOW)
1249 obj->bind_now = true;
1250 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1254 case DT_MIPS_LOCAL_GOTNO:
1255 obj->local_gotno = dynp->d_un.d_val;
1258 case DT_MIPS_SYMTABNO:
1259 obj->symtabno = dynp->d_un.d_val;
1262 case DT_MIPS_GOTSYM:
1263 obj->gotsym = dynp->d_un.d_val;
1266 case DT_MIPS_RLD_MAP:
1267 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1271 #ifdef __powerpc64__
1272 case DT_PPC64_GLINK:
1273 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1278 if (dynp->d_un.d_val & DF_1_NOOPEN)
1279 obj->z_noopen = true;
1280 if (dynp->d_un.d_val & DF_1_ORIGIN)
1281 obj->z_origin = true;
1282 if (dynp->d_un.d_val & DF_1_GLOBAL)
1283 obj->z_global = true;
1284 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1285 obj->bind_now = true;
1286 if (dynp->d_un.d_val & DF_1_NODELETE)
1287 obj->z_nodelete = true;
1288 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1289 obj->z_loadfltr = true;
1290 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1291 obj->z_interpose = true;
1292 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1293 obj->z_nodeflib = true;
1298 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1305 obj->traced = false;
1307 if (plttype == DT_RELA) {
1308 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1310 obj->pltrelasize = obj->pltrelsize;
1311 obj->pltrelsize = 0;
1314 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1315 if (obj->valid_hash_sysv)
1316 obj->dynsymcount = obj->nchains;
1317 else if (obj->valid_hash_gnu) {
1318 obj->dynsymcount = 0;
1319 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1320 if (obj->buckets_gnu[bkt] == 0)
1322 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1325 while ((*hashval++ & 1u) == 0);
1327 obj->dynsymcount += obj->symndx_gnu;
1332 obj_resolve_origin(Obj_Entry *obj)
1335 if (obj->origin_path != NULL)
1337 obj->origin_path = xmalloc(PATH_MAX);
1338 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1342 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1343 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1346 if (obj->z_origin && !obj_resolve_origin(obj))
1349 if (dyn_runpath != NULL) {
1350 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1351 obj->runpath = origin_subst(obj, obj->runpath);
1352 } else if (dyn_rpath != NULL) {
1353 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1354 obj->rpath = origin_subst(obj, obj->rpath);
1356 if (dyn_soname != NULL)
1357 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1361 digest_dynamic(Obj_Entry *obj, int early)
1363 const Elf_Dyn *dyn_rpath;
1364 const Elf_Dyn *dyn_soname;
1365 const Elf_Dyn *dyn_runpath;
1367 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1368 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1372 * Process a shared object's program header. This is used only for the
1373 * main program, when the kernel has already loaded the main program
1374 * into memory before calling the dynamic linker. It creates and
1375 * returns an Obj_Entry structure.
1378 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1381 const Elf_Phdr *phlimit = phdr + phnum;
1383 Elf_Addr note_start, note_end;
1387 for (ph = phdr; ph < phlimit; ph++) {
1388 if (ph->p_type != PT_PHDR)
1392 obj->phsize = ph->p_memsz;
1393 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1397 obj->stack_flags = PF_X | PF_R | PF_W;
1399 for (ph = phdr; ph < phlimit; ph++) {
1400 switch (ph->p_type) {
1403 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1407 if (nsegs == 0) { /* First load segment */
1408 obj->vaddrbase = trunc_page(ph->p_vaddr);
1409 obj->mapbase = obj->vaddrbase + obj->relocbase;
1410 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1412 } else { /* Last load segment */
1413 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1420 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1425 obj->tlssize = ph->p_memsz;
1426 obj->tlsalign = ph->p_align;
1427 obj->tlsinitsize = ph->p_filesz;
1428 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1432 obj->stack_flags = ph->p_flags;
1436 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1437 obj->relro_size = round_page(ph->p_memsz);
1441 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1442 note_end = note_start + ph->p_filesz;
1443 digest_notes(obj, note_start, note_end);
1448 _rtld_error("%s: too few PT_LOAD segments", path);
1457 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1459 const Elf_Note *note;
1460 const char *note_name;
1463 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1464 note = (const Elf_Note *)((const char *)(note + 1) +
1465 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1466 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1467 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1468 note->n_descsz != sizeof(int32_t))
1470 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1471 note->n_type != NT_FREEBSD_NOINIT_TAG)
1473 note_name = (const char *)(note + 1);
1474 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1475 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1477 switch (note->n_type) {
1478 case NT_FREEBSD_ABI_TAG:
1479 /* FreeBSD osrel note */
1480 p = (uintptr_t)(note + 1);
1481 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1482 obj->osrel = *(const int32_t *)(p);
1483 dbg("note osrel %d", obj->osrel);
1485 case NT_FREEBSD_NOINIT_TAG:
1486 /* FreeBSD 'crt does not call init' note */
1487 obj->crt_no_init = true;
1488 dbg("note crt_no_init");
1495 dlcheck(void *handle)
1499 TAILQ_FOREACH(obj, &obj_list, next) {
1500 if (obj == (Obj_Entry *) handle)
1504 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1505 _rtld_error("Invalid shared object handle %p", handle);
1512 * If the given object is already in the donelist, return true. Otherwise
1513 * add the object to the list and return false.
1516 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1520 for (i = 0; i < dlp->num_used; i++)
1521 if (dlp->objs[i] == obj)
1524 * Our donelist allocation should always be sufficient. But if
1525 * our threads locking isn't working properly, more shared objects
1526 * could have been loaded since we allocated the list. That should
1527 * never happen, but we'll handle it properly just in case it does.
1529 if (dlp->num_used < dlp->num_alloc)
1530 dlp->objs[dlp->num_used++] = obj;
1535 * Hash function for symbol table lookup. Don't even think about changing
1536 * this. It is specified by the System V ABI.
1539 elf_hash(const char *name)
1541 const unsigned char *p = (const unsigned char *) name;
1542 unsigned long h = 0;
1545 while (*p != '\0') {
1546 h = (h << 4) + *p++;
1547 if ((g = h & 0xf0000000) != 0)
1555 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1556 * unsigned in case it's implemented with a wider type.
1559 gnu_hash(const char *s)
1565 for (c = *s; c != '\0'; c = *++s)
1567 return (h & 0xffffffff);
1572 * Find the library with the given name, and return its full pathname.
1573 * The returned string is dynamically allocated. Generates an error
1574 * message and returns NULL if the library cannot be found.
1576 * If the second argument is non-NULL, then it refers to an already-
1577 * loaded shared object, whose library search path will be searched.
1579 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1580 * descriptor (which is close-on-exec) will be passed out via the third
1583 * The search order is:
1584 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1585 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1587 * DT_RUNPATH in the referencing file
1588 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1590 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1592 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1595 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1597 char *name, *pathname, *refobj_path;
1598 bool nodeflib, objgiven;
1600 objgiven = refobj != NULL;
1602 if (libmap_disable || !objgiven ||
1603 (name = lm_find(refobj->path, xname)) == NULL)
1604 name = (char *)xname;
1606 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1607 if (name[0] != '/' && !trust) {
1608 _rtld_error("Absolute pathname required "
1609 "for shared object \"%s\"", name);
1612 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1613 __DECONST(char *, name)));
1616 dbg(" Searching for \"%s\"", name);
1617 refobj_path = objgiven ? refobj->path : NULL;
1620 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1621 * back to pre-conforming behaviour if user requested so with
1622 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1625 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1626 pathname = search_library_path(name, ld_library_path,
1628 if (pathname != NULL)
1630 if (refobj != NULL) {
1631 pathname = search_library_path(name, refobj->rpath,
1633 if (pathname != NULL)
1636 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1637 if (pathname != NULL)
1639 pathname = search_library_path(name, gethints(false),
1641 if (pathname != NULL)
1643 pathname = search_library_path(name, ld_standard_library_path,
1645 if (pathname != NULL)
1648 nodeflib = objgiven ? refobj->z_nodeflib : false;
1650 pathname = search_library_path(name, refobj->rpath,
1652 if (pathname != NULL)
1655 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1656 pathname = search_library_path(name, obj_main->rpath,
1658 if (pathname != NULL)
1661 pathname = search_library_path(name, ld_library_path,
1663 if (pathname != NULL)
1666 pathname = search_library_path(name, refobj->runpath,
1668 if (pathname != NULL)
1671 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1672 if (pathname != NULL)
1674 pathname = search_library_path(name, gethints(nodeflib),
1676 if (pathname != NULL)
1678 if (objgiven && !nodeflib) {
1679 pathname = search_library_path(name,
1680 ld_standard_library_path, refobj_path, fdp);
1681 if (pathname != NULL)
1686 if (objgiven && refobj->path != NULL) {
1687 _rtld_error("Shared object \"%s\" not found, "
1688 "required by \"%s\"", name, basename(refobj->path));
1690 _rtld_error("Shared object \"%s\" not found", name);
1696 * Given a symbol number in a referencing object, find the corresponding
1697 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1698 * no definition was found. Returns a pointer to the Obj_Entry of the
1699 * defining object via the reference parameter DEFOBJ_OUT.
1702 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1703 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1704 RtldLockState *lockstate)
1708 const Obj_Entry *defobj;
1709 const Ver_Entry *ve;
1715 * If we have already found this symbol, get the information from
1718 if (symnum >= refobj->dynsymcount)
1719 return NULL; /* Bad object */
1720 if (cache != NULL && cache[symnum].sym != NULL) {
1721 *defobj_out = cache[symnum].obj;
1722 return cache[symnum].sym;
1725 ref = refobj->symtab + symnum;
1726 name = refobj->strtab + ref->st_name;
1732 * We don't have to do a full scale lookup if the symbol is local.
1733 * We know it will bind to the instance in this load module; to
1734 * which we already have a pointer (ie ref). By not doing a lookup,
1735 * we not only improve performance, but it also avoids unresolvable
1736 * symbols when local symbols are not in the hash table. This has
1737 * been seen with the ia64 toolchain.
1739 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1740 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1741 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1744 symlook_init(&req, name);
1746 ve = req.ventry = fetch_ventry(refobj, symnum);
1747 req.lockstate = lockstate;
1748 res = symlook_default(&req, refobj);
1751 defobj = req.defobj_out;
1759 * If we found no definition and the reference is weak, treat the
1760 * symbol as having the value zero.
1762 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1768 *defobj_out = defobj;
1769 /* Record the information in the cache to avoid subsequent lookups. */
1770 if (cache != NULL) {
1771 cache[symnum].sym = def;
1772 cache[symnum].obj = defobj;
1775 if (refobj != &obj_rtld)
1776 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1777 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1783 * Return the search path from the ldconfig hints file, reading it if
1784 * necessary. If nostdlib is true, then the default search paths are
1785 * not added to result.
1787 * Returns NULL if there are problems with the hints file,
1788 * or if the search path there is empty.
1791 gethints(bool nostdlib)
1793 static char *hints, *filtered_path;
1794 static struct elfhints_hdr hdr;
1795 struct fill_search_info_args sargs, hargs;
1796 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1797 struct dl_serpath *SLPpath, *hintpath;
1799 struct stat hint_stat;
1800 unsigned int SLPndx, hintndx, fndx, fcount;
1806 /* First call, read the hints file */
1807 if (hints == NULL) {
1808 /* Keep from trying again in case the hints file is bad. */
1811 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1815 * Check of hdr.dirlistlen value against type limit
1816 * intends to pacify static analyzers. Further
1817 * paranoia leads to checks that dirlist is fully
1818 * contained in the file range.
1820 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1821 hdr.magic != ELFHINTS_MAGIC ||
1822 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1823 fstat(fd, &hint_stat) == -1) {
1830 if (dl + hdr.dirlist < dl)
1833 if (dl + hdr.dirlistlen < dl)
1835 dl += hdr.dirlistlen;
1836 if (dl > hint_stat.st_size)
1838 p = xmalloc(hdr.dirlistlen + 1);
1839 if (pread(fd, p, hdr.dirlistlen + 1,
1840 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1841 p[hdr.dirlistlen] != '\0') {
1850 * If caller agreed to receive list which includes the default
1851 * paths, we are done. Otherwise, if we still did not
1852 * calculated filtered result, do it now.
1855 return (hints[0] != '\0' ? hints : NULL);
1856 if (filtered_path != NULL)
1860 * Obtain the list of all configured search paths, and the
1861 * list of the default paths.
1863 * First estimate the size of the results.
1865 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1867 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1870 sargs.request = RTLD_DI_SERINFOSIZE;
1871 sargs.serinfo = &smeta;
1872 hargs.request = RTLD_DI_SERINFOSIZE;
1873 hargs.serinfo = &hmeta;
1875 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1877 path_enumerate(hints, fill_search_info, NULL, &hargs);
1879 SLPinfo = xmalloc(smeta.dls_size);
1880 hintinfo = xmalloc(hmeta.dls_size);
1883 * Next fetch both sets of paths.
1885 sargs.request = RTLD_DI_SERINFO;
1886 sargs.serinfo = SLPinfo;
1887 sargs.serpath = &SLPinfo->dls_serpath[0];
1888 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1890 hargs.request = RTLD_DI_SERINFO;
1891 hargs.serinfo = hintinfo;
1892 hargs.serpath = &hintinfo->dls_serpath[0];
1893 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1895 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1897 path_enumerate(hints, fill_search_info, NULL, &hargs);
1900 * Now calculate the difference between two sets, by excluding
1901 * standard paths from the full set.
1905 filtered_path = xmalloc(hdr.dirlistlen + 1);
1906 hintpath = &hintinfo->dls_serpath[0];
1907 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1909 SLPpath = &SLPinfo->dls_serpath[0];
1911 * Check each standard path against current.
1913 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1914 /* matched, skip the path */
1915 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1923 * Not matched against any standard path, add the path
1924 * to result. Separate consequtive paths with ':'.
1927 filtered_path[fndx] = ':';
1931 flen = strlen(hintpath->dls_name);
1932 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1935 filtered_path[fndx] = '\0';
1941 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1945 init_dag(Obj_Entry *root)
1947 const Needed_Entry *needed;
1948 const Objlist_Entry *elm;
1951 if (root->dag_inited)
1953 donelist_init(&donelist);
1955 /* Root object belongs to own DAG. */
1956 objlist_push_tail(&root->dldags, root);
1957 objlist_push_tail(&root->dagmembers, root);
1958 donelist_check(&donelist, root);
1961 * Add dependencies of root object to DAG in breadth order
1962 * by exploiting the fact that each new object get added
1963 * to the tail of the dagmembers list.
1965 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1966 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1967 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1969 objlist_push_tail(&needed->obj->dldags, root);
1970 objlist_push_tail(&root->dagmembers, needed->obj);
1973 root->dag_inited = true;
1977 init_marker(Obj_Entry *marker)
1980 bzero(marker, sizeof(*marker));
1981 marker->marker = true;
1985 globallist_curr(const Obj_Entry *obj)
1992 return (__DECONST(Obj_Entry *, obj));
1993 obj = TAILQ_PREV(obj, obj_entry_q, next);
1998 globallist_next(const Obj_Entry *obj)
2002 obj = TAILQ_NEXT(obj, next);
2006 return (__DECONST(Obj_Entry *, obj));
2010 /* Prevent the object from being unmapped while the bind lock is dropped. */
2012 hold_object(Obj_Entry *obj)
2019 unhold_object(Obj_Entry *obj)
2022 assert(obj->holdcount > 0);
2023 if (--obj->holdcount == 0 && obj->unholdfree)
2024 release_object(obj);
2028 process_z(Obj_Entry *root)
2030 const Objlist_Entry *elm;
2034 * Walk over object DAG and process every dependent object
2035 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2036 * to grow their own DAG.
2038 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2039 * symlook_global() to work.
2041 * For DF_1_NODELETE, the DAG should have its reference upped.
2043 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2047 if (obj->z_nodelete && !obj->ref_nodel) {
2048 dbg("obj %s -z nodelete", obj->path);
2051 obj->ref_nodel = true;
2053 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2054 dbg("obj %s -z global", obj->path);
2055 objlist_push_tail(&list_global, obj);
2061 * Initialize the dynamic linker. The argument is the address at which
2062 * the dynamic linker has been mapped into memory. The primary task of
2063 * this function is to relocate the dynamic linker.
2066 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2068 Obj_Entry objtmp; /* Temporary rtld object */
2069 const Elf_Ehdr *ehdr;
2070 const Elf_Dyn *dyn_rpath;
2071 const Elf_Dyn *dyn_soname;
2072 const Elf_Dyn *dyn_runpath;
2074 #ifdef RTLD_INIT_PAGESIZES_EARLY
2075 /* The page size is required by the dynamic memory allocator. */
2076 init_pagesizes(aux_info);
2080 * Conjure up an Obj_Entry structure for the dynamic linker.
2082 * The "path" member can't be initialized yet because string constants
2083 * cannot yet be accessed. Below we will set it correctly.
2085 memset(&objtmp, 0, sizeof(objtmp));
2088 objtmp.mapbase = mapbase;
2090 objtmp.relocbase = mapbase;
2093 objtmp.dynamic = rtld_dynamic(&objtmp);
2094 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2095 assert(objtmp.needed == NULL);
2096 #if !defined(__mips__)
2097 /* MIPS has a bogus DT_TEXTREL. */
2098 assert(!objtmp.textrel);
2101 * Temporarily put the dynamic linker entry into the object list, so
2102 * that symbols can be found.
2104 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2106 ehdr = (Elf_Ehdr *)mapbase;
2107 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2108 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2110 /* Initialize the object list. */
2111 TAILQ_INIT(&obj_list);
2113 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2114 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2116 #ifndef RTLD_INIT_PAGESIZES_EARLY
2117 /* The page size is required by the dynamic memory allocator. */
2118 init_pagesizes(aux_info);
2121 if (aux_info[AT_OSRELDATE] != NULL)
2122 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2124 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2126 /* Replace the path with a dynamically allocated copy. */
2127 obj_rtld.path = xstrdup(ld_path_rtld);
2129 r_debug.r_brk = r_debug_state;
2130 r_debug.r_state = RT_CONSISTENT;
2134 * Retrieve the array of supported page sizes. The kernel provides the page
2135 * sizes in increasing order.
2138 init_pagesizes(Elf_Auxinfo **aux_info)
2140 static size_t psa[MAXPAGESIZES];
2144 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2146 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2147 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2150 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2153 /* As a fallback, retrieve the base page size. */
2154 size = sizeof(psa[0]);
2155 if (aux_info[AT_PAGESZ] != NULL) {
2156 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2160 mib[1] = HW_PAGESIZE;
2164 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2165 _rtld_error("sysctl for hw.pagesize(s) failed");
2171 npagesizes = size / sizeof(pagesizes[0]);
2172 /* Discard any invalid entries at the end of the array. */
2173 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2178 * Add the init functions from a needed object list (and its recursive
2179 * needed objects) to "list". This is not used directly; it is a helper
2180 * function for initlist_add_objects(). The write lock must be held
2181 * when this function is called.
2184 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2186 /* Recursively process the successor needed objects. */
2187 if (needed->next != NULL)
2188 initlist_add_neededs(needed->next, list);
2190 /* Process the current needed object. */
2191 if (needed->obj != NULL)
2192 initlist_add_objects(needed->obj, needed->obj, list);
2196 * Scan all of the DAGs rooted in the range of objects from "obj" to
2197 * "tail" and add their init functions to "list". This recurses over
2198 * the DAGs and ensure the proper init ordering such that each object's
2199 * needed libraries are initialized before the object itself. At the
2200 * same time, this function adds the objects to the global finalization
2201 * list "list_fini" in the opposite order. The write lock must be
2202 * held when this function is called.
2205 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2209 if (obj->init_scanned || obj->init_done)
2211 obj->init_scanned = true;
2213 /* Recursively process the successor objects. */
2214 nobj = globallist_next(obj);
2215 if (nobj != NULL && obj != tail)
2216 initlist_add_objects(nobj, tail, list);
2218 /* Recursively process the needed objects. */
2219 if (obj->needed != NULL)
2220 initlist_add_neededs(obj->needed, list);
2221 if (obj->needed_filtees != NULL)
2222 initlist_add_neededs(obj->needed_filtees, list);
2223 if (obj->needed_aux_filtees != NULL)
2224 initlist_add_neededs(obj->needed_aux_filtees, list);
2226 /* Add the object to the init list. */
2227 objlist_push_tail(list, obj);
2229 /* Add the object to the global fini list in the reverse order. */
2230 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2231 && !obj->on_fini_list) {
2232 objlist_push_head(&list_fini, obj);
2233 obj->on_fini_list = true;
2238 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2242 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2244 Needed_Entry *needed, *needed1;
2246 for (needed = n; needed != NULL; needed = needed->next) {
2247 if (needed->obj != NULL) {
2248 dlclose_locked(needed->obj, lockstate);
2252 for (needed = n; needed != NULL; needed = needed1) {
2253 needed1 = needed->next;
2259 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2262 free_needed_filtees(obj->needed_filtees, lockstate);
2263 obj->needed_filtees = NULL;
2264 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2265 obj->needed_aux_filtees = NULL;
2266 obj->filtees_loaded = false;
2270 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2271 RtldLockState *lockstate)
2274 for (; needed != NULL; needed = needed->next) {
2275 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2276 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2277 RTLD_LOCAL, lockstate);
2282 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2285 lock_restart_for_upgrade(lockstate);
2286 if (!obj->filtees_loaded) {
2287 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2288 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2289 obj->filtees_loaded = true;
2294 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2298 for (; needed != NULL; needed = needed->next) {
2299 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2300 flags & ~RTLD_LO_NOLOAD);
2301 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2308 * Given a shared object, traverse its list of needed objects, and load
2309 * each of them. Returns 0 on success. Generates an error message and
2310 * returns -1 on failure.
2313 load_needed_objects(Obj_Entry *first, int flags)
2317 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2320 if (process_needed(obj, obj->needed, flags) == -1)
2327 load_preload_objects(void)
2329 char *p = ld_preload;
2331 static const char delim[] = " \t:;";
2336 p += strspn(p, delim);
2337 while (*p != '\0') {
2338 size_t len = strcspn(p, delim);
2343 obj = load_object(p, -1, NULL, 0);
2345 return -1; /* XXX - cleanup */
2346 obj->z_interpose = true;
2349 p += strspn(p, delim);
2351 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2356 printable_path(const char *path)
2359 return (path == NULL ? "<unknown>" : path);
2363 * Load a shared object into memory, if it is not already loaded. The
2364 * object may be specified by name or by user-supplied file descriptor
2365 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2368 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2372 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2381 TAILQ_FOREACH(obj, &obj_list, next) {
2382 if (obj->marker || obj->doomed)
2384 if (object_match_name(obj, name))
2388 path = find_library(name, refobj, &fd);
2396 * search_library_pathfds() opens a fresh file descriptor for the
2397 * library, so there is no need to dup().
2399 } else if (fd_u == -1) {
2401 * If we didn't find a match by pathname, or the name is not
2402 * supplied, open the file and check again by device and inode.
2403 * This avoids false mismatches caused by multiple links or ".."
2406 * To avoid a race, we open the file and use fstat() rather than
2409 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2410 _rtld_error("Cannot open \"%s\"", path);
2415 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2417 _rtld_error("Cannot dup fd");
2422 if (fstat(fd, &sb) == -1) {
2423 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2428 TAILQ_FOREACH(obj, &obj_list, next) {
2429 if (obj->marker || obj->doomed)
2431 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2434 if (obj != NULL && name != NULL) {
2435 object_add_name(obj, name);
2440 if (flags & RTLD_LO_NOLOAD) {
2446 /* First use of this object, so we must map it in */
2447 obj = do_load_object(fd, name, path, &sb, flags);
2456 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2463 * but first, make sure that environment variables haven't been
2464 * used to circumvent the noexec flag on a filesystem.
2466 if (dangerous_ld_env) {
2467 if (fstatfs(fd, &fs) != 0) {
2468 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2471 if (fs.f_flags & MNT_NOEXEC) {
2472 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2476 dbg("loading \"%s\"", printable_path(path));
2477 obj = map_object(fd, printable_path(path), sbp);
2482 * If DT_SONAME is present in the object, digest_dynamic2 already
2483 * added it to the object names.
2486 object_add_name(obj, name);
2488 digest_dynamic(obj, 0);
2489 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2490 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2491 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2493 dbg("refusing to load non-loadable \"%s\"", obj->path);
2494 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2495 munmap(obj->mapbase, obj->mapsize);
2500 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2501 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2504 linkmap_add(obj); /* for GDB & dlinfo() */
2505 max_stack_flags |= obj->stack_flags;
2507 dbg(" %p .. %p: %s", obj->mapbase,
2508 obj->mapbase + obj->mapsize - 1, obj->path);
2510 dbg(" WARNING: %s has impure text", obj->path);
2511 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2518 obj_from_addr(const void *addr)
2522 TAILQ_FOREACH(obj, &obj_list, next) {
2525 if (addr < (void *) obj->mapbase)
2527 if (addr < (void *) (obj->mapbase + obj->mapsize))
2536 Elf_Addr *preinit_addr;
2539 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2540 if (preinit_addr == NULL)
2543 for (index = 0; index < obj_main->preinit_array_num; index++) {
2544 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2545 dbg("calling preinit function for %s at %p", obj_main->path,
2546 (void *)preinit_addr[index]);
2547 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2548 0, 0, obj_main->path);
2549 call_init_pointer(obj_main, preinit_addr[index]);
2555 * Call the finalization functions for each of the objects in "list"
2556 * belonging to the DAG of "root" and referenced once. If NULL "root"
2557 * is specified, every finalization function will be called regardless
2558 * of the reference count and the list elements won't be freed. All of
2559 * the objects are expected to have non-NULL fini functions.
2562 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2566 Elf_Addr *fini_addr;
2569 assert(root == NULL || root->refcount == 1);
2572 root->doomed = true;
2575 * Preserve the current error message since a fini function might
2576 * call into the dynamic linker and overwrite it.
2578 saved_msg = errmsg_save();
2580 STAILQ_FOREACH(elm, list, link) {
2581 if (root != NULL && (elm->obj->refcount != 1 ||
2582 objlist_find(&root->dagmembers, elm->obj) == NULL))
2584 /* Remove object from fini list to prevent recursive invocation. */
2585 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2586 /* Ensure that new references cannot be acquired. */
2587 elm->obj->doomed = true;
2589 hold_object(elm->obj);
2590 lock_release(rtld_bind_lock, lockstate);
2592 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2593 * When this happens, DT_FINI_ARRAY is processed first.
2595 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2596 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2597 for (index = elm->obj->fini_array_num - 1; index >= 0;
2599 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2600 dbg("calling fini function for %s at %p",
2601 elm->obj->path, (void *)fini_addr[index]);
2602 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2603 (void *)fini_addr[index], 0, 0, elm->obj->path);
2604 call_initfini_pointer(elm->obj, fini_addr[index]);
2608 if (elm->obj->fini != (Elf_Addr)NULL) {
2609 dbg("calling fini function for %s at %p", elm->obj->path,
2610 (void *)elm->obj->fini);
2611 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2612 0, 0, elm->obj->path);
2613 call_initfini_pointer(elm->obj, elm->obj->fini);
2615 wlock_acquire(rtld_bind_lock, lockstate);
2616 unhold_object(elm->obj);
2617 /* No need to free anything if process is going down. */
2621 * We must restart the list traversal after every fini call
2622 * because a dlclose() call from the fini function or from
2623 * another thread might have modified the reference counts.
2627 } while (elm != NULL);
2628 errmsg_restore(saved_msg);
2632 * Call the initialization functions for each of the objects in
2633 * "list". All of the objects are expected to have non-NULL init
2637 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2642 Elf_Addr *init_addr;
2646 * Clean init_scanned flag so that objects can be rechecked and
2647 * possibly initialized earlier if any of vectors called below
2648 * cause the change by using dlopen.
2650 TAILQ_FOREACH(obj, &obj_list, next) {
2653 obj->init_scanned = false;
2657 * Preserve the current error message since an init function might
2658 * call into the dynamic linker and overwrite it.
2660 saved_msg = errmsg_save();
2661 STAILQ_FOREACH(elm, list, link) {
2662 if (elm->obj->init_done) /* Initialized early. */
2665 * Race: other thread might try to use this object before current
2666 * one completes the initialization. Not much can be done here
2667 * without better locking.
2669 elm->obj->init_done = true;
2670 hold_object(elm->obj);
2671 lock_release(rtld_bind_lock, lockstate);
2674 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2675 * When this happens, DT_INIT is processed first.
2677 if (elm->obj->init != (Elf_Addr)NULL) {
2678 dbg("calling init function for %s at %p", elm->obj->path,
2679 (void *)elm->obj->init);
2680 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2681 0, 0, elm->obj->path);
2682 call_initfini_pointer(elm->obj, elm->obj->init);
2684 init_addr = (Elf_Addr *)elm->obj->init_array;
2685 if (init_addr != NULL) {
2686 for (index = 0; index < elm->obj->init_array_num; index++) {
2687 if (init_addr[index] != 0 && init_addr[index] != 1) {
2688 dbg("calling init function for %s at %p", elm->obj->path,
2689 (void *)init_addr[index]);
2690 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2691 (void *)init_addr[index], 0, 0, elm->obj->path);
2692 call_init_pointer(elm->obj, init_addr[index]);
2696 wlock_acquire(rtld_bind_lock, lockstate);
2697 unhold_object(elm->obj);
2699 errmsg_restore(saved_msg);
2703 objlist_clear(Objlist *list)
2707 while (!STAILQ_EMPTY(list)) {
2708 elm = STAILQ_FIRST(list);
2709 STAILQ_REMOVE_HEAD(list, link);
2714 static Objlist_Entry *
2715 objlist_find(Objlist *list, const Obj_Entry *obj)
2719 STAILQ_FOREACH(elm, list, link)
2720 if (elm->obj == obj)
2726 objlist_init(Objlist *list)
2732 objlist_push_head(Objlist *list, Obj_Entry *obj)
2736 elm = NEW(Objlist_Entry);
2738 STAILQ_INSERT_HEAD(list, elm, link);
2742 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2746 elm = NEW(Objlist_Entry);
2748 STAILQ_INSERT_TAIL(list, elm, link);
2752 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2754 Objlist_Entry *elm, *listelm;
2756 STAILQ_FOREACH(listelm, list, link) {
2757 if (listelm->obj == listobj)
2760 elm = NEW(Objlist_Entry);
2762 if (listelm != NULL)
2763 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2765 STAILQ_INSERT_TAIL(list, elm, link);
2769 objlist_remove(Objlist *list, Obj_Entry *obj)
2773 if ((elm = objlist_find(list, obj)) != NULL) {
2774 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2780 * Relocate dag rooted in the specified object.
2781 * Returns 0 on success, or -1 on failure.
2785 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2786 int flags, RtldLockState *lockstate)
2792 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2793 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2802 * Prepare for, or clean after, relocating an object marked with
2803 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2804 * segments are remapped read-write. After relocations are done, the
2805 * segment's permissions are returned back to the modes specified in
2806 * the phdrs. If any relocation happened, or always for wired
2807 * program, COW is triggered.
2810 reloc_textrel_prot(Obj_Entry *obj, bool before)
2817 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2819 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2821 base = obj->relocbase + trunc_page(ph->p_vaddr);
2822 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2823 trunc_page(ph->p_vaddr);
2824 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2825 if (mprotect(base, sz, prot) == -1) {
2826 _rtld_error("%s: Cannot write-%sable text segment: %s",
2827 obj->path, before ? "en" : "dis",
2828 rtld_strerror(errno));
2836 * Relocate single object.
2837 * Returns 0 on success, or -1 on failure.
2840 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2841 int flags, RtldLockState *lockstate)
2846 obj->relocated = true;
2848 dbg("relocating \"%s\"", obj->path);
2850 if (obj->symtab == NULL || obj->strtab == NULL ||
2851 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2852 _rtld_error("%s: Shared object has no run-time symbol table",
2857 /* There are relocations to the write-protected text segment. */
2858 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2861 /* Process the non-PLT non-IFUNC relocations. */
2862 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2865 /* Re-protected the text segment. */
2866 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2869 /* Set the special PLT or GOT entries. */
2872 /* Process the PLT relocations. */
2873 if (reloc_plt(obj) == -1)
2875 /* Relocate the jump slots if we are doing immediate binding. */
2876 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
2880 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2884 * Set up the magic number and version in the Obj_Entry. These
2885 * were checked in the crt1.o from the original ElfKit, so we
2886 * set them for backward compatibility.
2888 obj->magic = RTLD_MAGIC;
2889 obj->version = RTLD_VERSION;
2895 * Relocate newly-loaded shared objects. The argument is a pointer to
2896 * the Obj_Entry for the first such object. All objects from the first
2897 * to the end of the list of objects are relocated. Returns 0 on success,
2901 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2902 int flags, RtldLockState *lockstate)
2907 for (error = 0, obj = first; obj != NULL;
2908 obj = TAILQ_NEXT(obj, next)) {
2911 error = relocate_object(obj, bind_now, rtldobj, flags,
2920 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2921 * referencing STT_GNU_IFUNC symbols is postponed till the other
2922 * relocations are done. The indirect functions specified as
2923 * ifunc are allowed to call other symbols, so we need to have
2924 * objects relocated before asking for resolution from indirects.
2926 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2927 * instead of the usual lazy handling of PLT slots. It is
2928 * consistent with how GNU does it.
2931 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2932 RtldLockState *lockstate)
2935 if (obj->ifuncs_resolved)
2937 obj->ifuncs_resolved = true;
2938 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2940 if ((obj->bind_now || bind_now) && obj->gnu_ifunc) {
2941 if (obj_disable_relro(obj) ||
2942 reloc_gnu_ifunc(obj, flags, lockstate) == -1 ||
2943 obj_enforce_relro(obj))
2950 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2951 RtldLockState *lockstate)
2956 STAILQ_FOREACH(elm, list, link) {
2960 if (resolve_object_ifunc(obj, bind_now, flags,
2968 * Cleanup procedure. It will be called (by the atexit mechanism) just
2969 * before the process exits.
2974 RtldLockState lockstate;
2976 wlock_acquire(rtld_bind_lock, &lockstate);
2978 objlist_call_fini(&list_fini, NULL, &lockstate);
2979 /* No need to remove the items from the list, since we are exiting. */
2980 if (!libmap_disable)
2982 lock_release(rtld_bind_lock, &lockstate);
2986 * Iterate over a search path, translate each element, and invoke the
2987 * callback on the result.
2990 path_enumerate(const char *path, path_enum_proc callback,
2991 const char *refobj_path, void *arg)
2997 path += strspn(path, ":;");
2998 while (*path != '\0') {
3002 len = strcspn(path, ":;");
3003 trans = lm_findn(refobj_path, path, len);
3005 res = callback(trans, strlen(trans), arg);
3007 res = callback(path, len, arg);
3013 path += strspn(path, ":;");
3019 struct try_library_args {
3028 try_library_path(const char *dir, size_t dirlen, void *param)
3030 struct try_library_args *arg;
3034 if (*dir == '/' || trust) {
3037 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3040 pathname = arg->buffer;
3041 strncpy(pathname, dir, dirlen);
3042 pathname[dirlen] = '/';
3043 strcpy(pathname + dirlen + 1, arg->name);
3045 dbg(" Trying \"%s\"", pathname);
3046 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3048 dbg(" Opened \"%s\", fd %d", pathname, fd);
3049 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3050 strcpy(pathname, arg->buffer);
3054 dbg(" Failed to open \"%s\": %s",
3055 pathname, rtld_strerror(errno));
3062 search_library_path(const char *name, const char *path,
3063 const char *refobj_path, int *fdp)
3066 struct try_library_args arg;
3072 arg.namelen = strlen(name);
3073 arg.buffer = xmalloc(PATH_MAX);
3074 arg.buflen = PATH_MAX;
3077 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3087 * Finds the library with the given name using the directory descriptors
3088 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3090 * Returns a freshly-opened close-on-exec file descriptor for the library,
3091 * or -1 if the library cannot be found.
3094 search_library_pathfds(const char *name, const char *path, int *fdp)
3096 char *envcopy, *fdstr, *found, *last_token;
3100 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3102 /* Don't load from user-specified libdirs into setuid binaries. */
3106 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3110 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3111 if (name[0] == '/') {
3112 dbg("Absolute path (%s) passed to %s", name, __func__);
3117 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3118 * copy of the path, as strtok_r rewrites separator tokens
3122 envcopy = xstrdup(path);
3123 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3124 fdstr = strtok_r(NULL, ":", &last_token)) {
3125 dirfd = parse_integer(fdstr);
3127 _rtld_error("failed to parse directory FD: '%s'",
3131 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3134 len = strlen(fdstr) + strlen(name) + 3;
3135 found = xmalloc(len);
3136 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3137 _rtld_error("error generating '%d/%s'",
3141 dbg("open('%s') => %d", found, fd);
3152 dlclose(void *handle)
3154 RtldLockState lockstate;
3157 wlock_acquire(rtld_bind_lock, &lockstate);
3158 error = dlclose_locked(handle, &lockstate);
3159 lock_release(rtld_bind_lock, &lockstate);
3164 dlclose_locked(void *handle, RtldLockState *lockstate)
3168 root = dlcheck(handle);
3171 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3174 /* Unreference the object and its dependencies. */
3175 root->dl_refcount--;
3177 if (root->refcount == 1) {
3179 * The object will be no longer referenced, so we must unload it.
3180 * First, call the fini functions.
3182 objlist_call_fini(&list_fini, root, lockstate);
3186 /* Finish cleaning up the newly-unreferenced objects. */
3187 GDB_STATE(RT_DELETE,&root->linkmap);
3188 unload_object(root, lockstate);
3189 GDB_STATE(RT_CONSISTENT,NULL);
3193 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3200 char *msg = error_message;
3201 error_message = NULL;
3206 * This function is deprecated and has no effect.
3209 dllockinit(void *context,
3210 void *(*lock_create)(void *context),
3211 void (*rlock_acquire)(void *lock),
3212 void (*wlock_acquire)(void *lock),
3213 void (*lock_release)(void *lock),
3214 void (*lock_destroy)(void *lock),
3215 void (*context_destroy)(void *context))
3217 static void *cur_context;
3218 static void (*cur_context_destroy)(void *);
3220 /* Just destroy the context from the previous call, if necessary. */
3221 if (cur_context_destroy != NULL)
3222 cur_context_destroy(cur_context);
3223 cur_context = context;
3224 cur_context_destroy = context_destroy;
3228 dlopen(const char *name, int mode)
3231 return (rtld_dlopen(name, -1, mode));
3235 fdlopen(int fd, int mode)
3238 return (rtld_dlopen(NULL, fd, mode));
3242 rtld_dlopen(const char *name, int fd, int mode)
3244 RtldLockState lockstate;
3247 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3248 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3249 if (ld_tracing != NULL) {
3250 rlock_acquire(rtld_bind_lock, &lockstate);
3251 if (sigsetjmp(lockstate.env, 0) != 0)
3252 lock_upgrade(rtld_bind_lock, &lockstate);
3253 environ = (char **)*get_program_var_addr("environ", &lockstate);
3254 lock_release(rtld_bind_lock, &lockstate);
3256 lo_flags = RTLD_LO_DLOPEN;
3257 if (mode & RTLD_NODELETE)
3258 lo_flags |= RTLD_LO_NODELETE;
3259 if (mode & RTLD_NOLOAD)
3260 lo_flags |= RTLD_LO_NOLOAD;
3261 if (ld_tracing != NULL)
3262 lo_flags |= RTLD_LO_TRACE;
3264 return (dlopen_object(name, fd, obj_main, lo_flags,
3265 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3269 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3274 if (obj->refcount == 0)
3275 unload_object(obj, lockstate);
3279 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3280 int mode, RtldLockState *lockstate)
3282 Obj_Entry *old_obj_tail;
3285 RtldLockState mlockstate;
3288 objlist_init(&initlist);
3290 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3291 wlock_acquire(rtld_bind_lock, &mlockstate);
3292 lockstate = &mlockstate;
3294 GDB_STATE(RT_ADD,NULL);
3296 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3298 if (name == NULL && fd == -1) {
3302 obj = load_object(name, fd, refobj, lo_flags);
3307 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3308 objlist_push_tail(&list_global, obj);
3309 if (globallist_next(old_obj_tail) != NULL) {
3310 /* We loaded something new. */
3311 assert(globallist_next(old_obj_tail) == obj);
3312 result = load_needed_objects(obj,
3313 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3317 result = rtld_verify_versions(&obj->dagmembers);
3318 if (result != -1 && ld_tracing)
3320 if (result == -1 || relocate_object_dag(obj,
3321 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3322 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3324 dlopen_cleanup(obj, lockstate);
3326 } else if (lo_flags & RTLD_LO_EARLY) {
3328 * Do not call the init functions for early loaded
3329 * filtees. The image is still not initialized enough
3332 * Our object is found by the global object list and
3333 * will be ordered among all init calls done right
3334 * before transferring control to main.
3337 /* Make list of init functions to call. */
3338 initlist_add_objects(obj, obj, &initlist);
3341 * Process all no_delete or global objects here, given
3342 * them own DAGs to prevent their dependencies from being
3343 * unloaded. This has to be done after we have loaded all
3344 * of the dependencies, so that we do not miss any.
3350 * Bump the reference counts for objects on this DAG. If
3351 * this is the first dlopen() call for the object that was
3352 * already loaded as a dependency, initialize the dag
3358 if ((lo_flags & RTLD_LO_TRACE) != 0)
3361 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3362 obj->z_nodelete) && !obj->ref_nodel) {
3363 dbg("obj %s nodelete", obj->path);
3365 obj->z_nodelete = obj->ref_nodel = true;
3369 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3371 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3373 if (!(lo_flags & RTLD_LO_EARLY)) {
3374 map_stacks_exec(lockstate);
3377 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3378 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3380 objlist_clear(&initlist);
3381 dlopen_cleanup(obj, lockstate);
3382 if (lockstate == &mlockstate)
3383 lock_release(rtld_bind_lock, lockstate);
3387 if (!(lo_flags & RTLD_LO_EARLY)) {
3388 /* Call the init functions. */
3389 objlist_call_init(&initlist, lockstate);
3391 objlist_clear(&initlist);
3392 if (lockstate == &mlockstate)
3393 lock_release(rtld_bind_lock, lockstate);
3396 trace_loaded_objects(obj);
3397 if (lockstate == &mlockstate)
3398 lock_release(rtld_bind_lock, lockstate);
3403 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3407 const Obj_Entry *obj, *defobj;
3410 RtldLockState lockstate;
3417 symlook_init(&req, name);
3419 req.flags = flags | SYMLOOK_IN_PLT;
3420 req.lockstate = &lockstate;
3422 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3423 rlock_acquire(rtld_bind_lock, &lockstate);
3424 if (sigsetjmp(lockstate.env, 0) != 0)
3425 lock_upgrade(rtld_bind_lock, &lockstate);
3426 if (handle == NULL || handle == RTLD_NEXT ||
3427 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3429 if ((obj = obj_from_addr(retaddr)) == NULL) {
3430 _rtld_error("Cannot determine caller's shared object");
3431 lock_release(rtld_bind_lock, &lockstate);
3432 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3435 if (handle == NULL) { /* Just the caller's shared object. */
3436 res = symlook_obj(&req, obj);
3439 defobj = req.defobj_out;
3441 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3442 handle == RTLD_SELF) { /* ... caller included */
3443 if (handle == RTLD_NEXT)
3444 obj = globallist_next(obj);
3445 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3448 res = symlook_obj(&req, obj);
3451 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3453 defobj = req.defobj_out;
3454 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3460 * Search the dynamic linker itself, and possibly resolve the
3461 * symbol from there. This is how the application links to
3462 * dynamic linker services such as dlopen.
3464 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3465 res = symlook_obj(&req, &obj_rtld);
3468 defobj = req.defobj_out;
3472 assert(handle == RTLD_DEFAULT);
3473 res = symlook_default(&req, obj);
3475 defobj = req.defobj_out;
3480 if ((obj = dlcheck(handle)) == NULL) {
3481 lock_release(rtld_bind_lock, &lockstate);
3482 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3486 donelist_init(&donelist);
3487 if (obj->mainprog) {
3488 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3489 res = symlook_global(&req, &donelist);
3492 defobj = req.defobj_out;
3495 * Search the dynamic linker itself, and possibly resolve the
3496 * symbol from there. This is how the application links to
3497 * dynamic linker services such as dlopen.
3499 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3500 res = symlook_obj(&req, &obj_rtld);
3503 defobj = req.defobj_out;
3508 /* Search the whole DAG rooted at the given object. */
3509 res = symlook_list(&req, &obj->dagmembers, &donelist);
3512 defobj = req.defobj_out;
3518 lock_release(rtld_bind_lock, &lockstate);
3521 * The value required by the caller is derived from the value
3522 * of the symbol. this is simply the relocated value of the
3525 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3526 sym = make_function_pointer(def, defobj);
3527 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3528 sym = rtld_resolve_ifunc(defobj, def);
3529 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3530 ti.ti_module = defobj->tlsindex;
3531 ti.ti_offset = def->st_value;
3532 sym = __tls_get_addr(&ti);
3534 sym = defobj->relocbase + def->st_value;
3535 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3539 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3540 ve != NULL ? ve->name : "");
3541 lock_release(rtld_bind_lock, &lockstate);
3542 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3547 dlsym(void *handle, const char *name)
3549 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3554 dlfunc(void *handle, const char *name)
3561 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3567 dlvsym(void *handle, const char *name, const char *version)
3571 ventry.name = version;
3573 ventry.hash = elf_hash(version);
3575 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3580 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3582 const Obj_Entry *obj;
3583 RtldLockState lockstate;
3585 rlock_acquire(rtld_bind_lock, &lockstate);
3586 obj = obj_from_addr(addr);
3588 _rtld_error("No shared object contains address");
3589 lock_release(rtld_bind_lock, &lockstate);
3592 rtld_fill_dl_phdr_info(obj, phdr_info);
3593 lock_release(rtld_bind_lock, &lockstate);
3598 dladdr(const void *addr, Dl_info *info)
3600 const Obj_Entry *obj;
3603 unsigned long symoffset;
3604 RtldLockState lockstate;
3606 rlock_acquire(rtld_bind_lock, &lockstate);
3607 obj = obj_from_addr(addr);
3609 _rtld_error("No shared object contains address");
3610 lock_release(rtld_bind_lock, &lockstate);
3613 info->dli_fname = obj->path;
3614 info->dli_fbase = obj->mapbase;
3615 info->dli_saddr = (void *)0;
3616 info->dli_sname = NULL;
3619 * Walk the symbol list looking for the symbol whose address is
3620 * closest to the address sent in.
3622 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3623 def = obj->symtab + symoffset;
3626 * For skip the symbol if st_shndx is either SHN_UNDEF or
3629 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3633 * If the symbol is greater than the specified address, or if it
3634 * is further away from addr than the current nearest symbol,
3637 symbol_addr = obj->relocbase + def->st_value;
3638 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3641 /* Update our idea of the nearest symbol. */
3642 info->dli_sname = obj->strtab + def->st_name;
3643 info->dli_saddr = symbol_addr;
3646 if (info->dli_saddr == addr)
3649 lock_release(rtld_bind_lock, &lockstate);
3654 dlinfo(void *handle, int request, void *p)
3656 const Obj_Entry *obj;
3657 RtldLockState lockstate;
3660 rlock_acquire(rtld_bind_lock, &lockstate);
3662 if (handle == NULL || handle == RTLD_SELF) {
3665 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3666 if ((obj = obj_from_addr(retaddr)) == NULL)
3667 _rtld_error("Cannot determine caller's shared object");
3669 obj = dlcheck(handle);
3672 lock_release(rtld_bind_lock, &lockstate);
3678 case RTLD_DI_LINKMAP:
3679 *((struct link_map const **)p) = &obj->linkmap;
3681 case RTLD_DI_ORIGIN:
3682 error = rtld_dirname(obj->path, p);
3685 case RTLD_DI_SERINFOSIZE:
3686 case RTLD_DI_SERINFO:
3687 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3691 _rtld_error("Invalid request %d passed to dlinfo()", request);
3695 lock_release(rtld_bind_lock, &lockstate);
3701 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3704 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3705 phdr_info->dlpi_name = obj->path;
3706 phdr_info->dlpi_phdr = obj->phdr;
3707 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3708 phdr_info->dlpi_tls_modid = obj->tlsindex;
3709 phdr_info->dlpi_tls_data = obj->tlsinit;
3710 phdr_info->dlpi_adds = obj_loads;
3711 phdr_info->dlpi_subs = obj_loads - obj_count;
3715 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3717 struct dl_phdr_info phdr_info;
3718 Obj_Entry *obj, marker;
3719 RtldLockState bind_lockstate, phdr_lockstate;
3722 init_marker(&marker);
3725 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3726 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3727 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3728 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3729 rtld_fill_dl_phdr_info(obj, &phdr_info);
3731 lock_release(rtld_bind_lock, &bind_lockstate);
3733 error = callback(&phdr_info, sizeof phdr_info, param);
3735 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3737 obj = globallist_next(&marker);
3738 TAILQ_REMOVE(&obj_list, &marker, next);
3740 lock_release(rtld_bind_lock, &bind_lockstate);
3741 lock_release(rtld_phdr_lock, &phdr_lockstate);
3747 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3748 lock_release(rtld_bind_lock, &bind_lockstate);
3749 error = callback(&phdr_info, sizeof(phdr_info), param);
3751 lock_release(rtld_phdr_lock, &phdr_lockstate);
3756 fill_search_info(const char *dir, size_t dirlen, void *param)
3758 struct fill_search_info_args *arg;
3762 if (arg->request == RTLD_DI_SERINFOSIZE) {
3763 arg->serinfo->dls_cnt ++;
3764 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3766 struct dl_serpath *s_entry;
3768 s_entry = arg->serpath;
3769 s_entry->dls_name = arg->strspace;
3770 s_entry->dls_flags = arg->flags;
3772 strncpy(arg->strspace, dir, dirlen);
3773 arg->strspace[dirlen] = '\0';
3775 arg->strspace += dirlen + 1;
3783 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3785 struct dl_serinfo _info;
3786 struct fill_search_info_args args;
3788 args.request = RTLD_DI_SERINFOSIZE;
3789 args.serinfo = &_info;
3791 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3794 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3795 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3796 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3797 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3798 if (!obj->z_nodeflib)
3799 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3802 if (request == RTLD_DI_SERINFOSIZE) {
3803 info->dls_size = _info.dls_size;
3804 info->dls_cnt = _info.dls_cnt;
3808 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3809 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3813 args.request = RTLD_DI_SERINFO;
3814 args.serinfo = info;
3815 args.serpath = &info->dls_serpath[0];
3816 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3818 args.flags = LA_SER_RUNPATH;
3819 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
3822 args.flags = LA_SER_LIBPATH;
3823 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
3826 args.flags = LA_SER_RUNPATH;
3827 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
3830 args.flags = LA_SER_CONFIG;
3831 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
3835 args.flags = LA_SER_DEFAULT;
3836 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
3837 fill_search_info, NULL, &args) != NULL)
3843 rtld_dirname(const char *path, char *bname)
3847 /* Empty or NULL string gets treated as "." */
3848 if (path == NULL || *path == '\0') {
3854 /* Strip trailing slashes */
3855 endp = path + strlen(path) - 1;
3856 while (endp > path && *endp == '/')
3859 /* Find the start of the dir */
3860 while (endp > path && *endp != '/')
3863 /* Either the dir is "/" or there are no slashes */
3865 bname[0] = *endp == '/' ? '/' : '.';
3871 } while (endp > path && *endp == '/');
3874 if (endp - path + 2 > PATH_MAX)
3876 _rtld_error("Filename is too long: %s", path);
3880 strncpy(bname, path, endp - path + 1);
3881 bname[endp - path + 1] = '\0';
3886 rtld_dirname_abs(const char *path, char *base)
3890 if (realpath(path, base) == NULL)
3892 dbg("%s -> %s", path, base);
3893 last = strrchr(base, '/');
3902 linkmap_add(Obj_Entry *obj)
3904 struct link_map *l = &obj->linkmap;
3905 struct link_map *prev;
3907 obj->linkmap.l_name = obj->path;
3908 obj->linkmap.l_addr = obj->mapbase;
3909 obj->linkmap.l_ld = obj->dynamic;
3911 /* GDB needs load offset on MIPS to use the symbols */
3912 obj->linkmap.l_offs = obj->relocbase;
3915 if (r_debug.r_map == NULL) {
3921 * Scan to the end of the list, but not past the entry for the
3922 * dynamic linker, which we want to keep at the very end.
3924 for (prev = r_debug.r_map;
3925 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3926 prev = prev->l_next)
3929 /* Link in the new entry. */
3931 l->l_next = prev->l_next;
3932 if (l->l_next != NULL)
3933 l->l_next->l_prev = l;
3938 linkmap_delete(Obj_Entry *obj)
3940 struct link_map *l = &obj->linkmap;
3942 if (l->l_prev == NULL) {
3943 if ((r_debug.r_map = l->l_next) != NULL)
3944 l->l_next->l_prev = NULL;
3948 if ((l->l_prev->l_next = l->l_next) != NULL)
3949 l->l_next->l_prev = l->l_prev;
3953 * Function for the debugger to set a breakpoint on to gain control.
3955 * The two parameters allow the debugger to easily find and determine
3956 * what the runtime loader is doing and to whom it is doing it.
3958 * When the loadhook trap is hit (r_debug_state, set at program
3959 * initialization), the arguments can be found on the stack:
3961 * +8 struct link_map *m
3962 * +4 struct r_debug *rd
3966 r_debug_state(struct r_debug* rd, struct link_map *m)
3969 * The following is a hack to force the compiler to emit calls to
3970 * this function, even when optimizing. If the function is empty,
3971 * the compiler is not obliged to emit any code for calls to it,
3972 * even when marked __noinline. However, gdb depends on those
3975 __compiler_membar();
3979 * A function called after init routines have completed. This can be used to
3980 * break before a program's entry routine is called, and can be used when
3981 * main is not available in the symbol table.
3984 _r_debug_postinit(struct link_map *m)
3987 /* See r_debug_state(). */
3988 __compiler_membar();
3992 release_object(Obj_Entry *obj)
3995 if (obj->holdcount > 0) {
3996 obj->unholdfree = true;
3999 munmap(obj->mapbase, obj->mapsize);
4000 linkmap_delete(obj);
4005 * Get address of the pointer variable in the main program.
4006 * Prefer non-weak symbol over the weak one.
4008 static const void **
4009 get_program_var_addr(const char *name, RtldLockState *lockstate)
4014 symlook_init(&req, name);
4015 req.lockstate = lockstate;
4016 donelist_init(&donelist);
4017 if (symlook_global(&req, &donelist) != 0)
4019 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4020 return ((const void **)make_function_pointer(req.sym_out,
4022 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4023 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4025 return ((const void **)(req.defobj_out->relocbase +
4026 req.sym_out->st_value));
4030 * Set a pointer variable in the main program to the given value. This
4031 * is used to set key variables such as "environ" before any of the
4032 * init functions are called.
4035 set_program_var(const char *name, const void *value)
4039 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4040 dbg("\"%s\": *%p <-- %p", name, addr, value);
4046 * Search the global objects, including dependencies and main object,
4047 * for the given symbol.
4050 symlook_global(SymLook *req, DoneList *donelist)
4053 const Objlist_Entry *elm;
4056 symlook_init_from_req(&req1, req);
4058 /* Search all objects loaded at program start up. */
4059 if (req->defobj_out == NULL ||
4060 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4061 res = symlook_list(&req1, &list_main, donelist);
4062 if (res == 0 && (req->defobj_out == NULL ||
4063 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4064 req->sym_out = req1.sym_out;
4065 req->defobj_out = req1.defobj_out;
4066 assert(req->defobj_out != NULL);
4070 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4071 STAILQ_FOREACH(elm, &list_global, link) {
4072 if (req->defobj_out != NULL &&
4073 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4075 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4076 if (res == 0 && (req->defobj_out == NULL ||
4077 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4078 req->sym_out = req1.sym_out;
4079 req->defobj_out = req1.defobj_out;
4080 assert(req->defobj_out != NULL);
4084 return (req->sym_out != NULL ? 0 : ESRCH);
4088 * Given a symbol name in a referencing object, find the corresponding
4089 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4090 * no definition was found. Returns a pointer to the Obj_Entry of the
4091 * defining object via the reference parameter DEFOBJ_OUT.
4094 symlook_default(SymLook *req, const Obj_Entry *refobj)
4097 const Objlist_Entry *elm;
4101 donelist_init(&donelist);
4102 symlook_init_from_req(&req1, req);
4105 * Look first in the referencing object if linked symbolically,
4106 * and similarly handle protected symbols.
4108 res = symlook_obj(&req1, refobj);
4109 if (res == 0 && (refobj->symbolic ||
4110 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4111 req->sym_out = req1.sym_out;
4112 req->defobj_out = req1.defobj_out;
4113 assert(req->defobj_out != NULL);
4115 if (refobj->symbolic || req->defobj_out != NULL)
4116 donelist_check(&donelist, refobj);
4118 symlook_global(req, &donelist);
4120 /* Search all dlopened DAGs containing the referencing object. */
4121 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4122 if (req->sym_out != NULL &&
4123 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4125 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4126 if (res == 0 && (req->sym_out == NULL ||
4127 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4128 req->sym_out = req1.sym_out;
4129 req->defobj_out = req1.defobj_out;
4130 assert(req->defobj_out != NULL);
4135 * Search the dynamic linker itself, and possibly resolve the
4136 * symbol from there. This is how the application links to
4137 * dynamic linker services such as dlopen.
4139 if (req->sym_out == NULL ||
4140 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4141 res = symlook_obj(&req1, &obj_rtld);
4143 req->sym_out = req1.sym_out;
4144 req->defobj_out = req1.defobj_out;
4145 assert(req->defobj_out != NULL);
4149 return (req->sym_out != NULL ? 0 : ESRCH);
4153 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4156 const Obj_Entry *defobj;
4157 const Objlist_Entry *elm;
4163 STAILQ_FOREACH(elm, objlist, link) {
4164 if (donelist_check(dlp, elm->obj))
4166 symlook_init_from_req(&req1, req);
4167 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4168 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4170 defobj = req1.defobj_out;
4171 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4178 req->defobj_out = defobj;
4185 * Search the chain of DAGS cointed to by the given Needed_Entry
4186 * for a symbol of the given name. Each DAG is scanned completely
4187 * before advancing to the next one. Returns a pointer to the symbol,
4188 * or NULL if no definition was found.
4191 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4194 const Needed_Entry *n;
4195 const Obj_Entry *defobj;
4201 symlook_init_from_req(&req1, req);
4202 for (n = needed; n != NULL; n = n->next) {
4203 if (n->obj == NULL ||
4204 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4206 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4208 defobj = req1.defobj_out;
4209 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4215 req->defobj_out = defobj;
4222 * Search the symbol table of a single shared object for a symbol of
4223 * the given name and version, if requested. Returns a pointer to the
4224 * symbol, or NULL if no definition was found. If the object is
4225 * filter, return filtered symbol from filtee.
4227 * The symbol's hash value is passed in for efficiency reasons; that
4228 * eliminates many recomputations of the hash value.
4231 symlook_obj(SymLook *req, const Obj_Entry *obj)
4235 int flags, res, mres;
4238 * If there is at least one valid hash at this point, we prefer to
4239 * use the faster GNU version if available.
4241 if (obj->valid_hash_gnu)
4242 mres = symlook_obj1_gnu(req, obj);
4243 else if (obj->valid_hash_sysv)
4244 mres = symlook_obj1_sysv(req, obj);
4249 if (obj->needed_filtees != NULL) {
4250 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4251 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4252 donelist_init(&donelist);
4253 symlook_init_from_req(&req1, req);
4254 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4256 req->sym_out = req1.sym_out;
4257 req->defobj_out = req1.defobj_out;
4261 if (obj->needed_aux_filtees != NULL) {
4262 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4263 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4264 donelist_init(&donelist);
4265 symlook_init_from_req(&req1, req);
4266 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4268 req->sym_out = req1.sym_out;
4269 req->defobj_out = req1.defobj_out;
4277 /* Symbol match routine common to both hash functions */
4279 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4280 const unsigned long symnum)
4283 const Elf_Sym *symp;
4286 symp = obj->symtab + symnum;
4287 strp = obj->strtab + symp->st_name;
4289 switch (ELF_ST_TYPE(symp->st_info)) {
4295 if (symp->st_value == 0)
4299 if (symp->st_shndx != SHN_UNDEF)
4302 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4303 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4310 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4313 if (req->ventry == NULL) {
4314 if (obj->versyms != NULL) {
4315 verndx = VER_NDX(obj->versyms[symnum]);
4316 if (verndx > obj->vernum) {
4318 "%s: symbol %s references wrong version %d",
4319 obj->path, obj->strtab + symnum, verndx);
4323 * If we are not called from dlsym (i.e. this
4324 * is a normal relocation from unversioned
4325 * binary), accept the symbol immediately if
4326 * it happens to have first version after this
4327 * shared object became versioned. Otherwise,
4328 * if symbol is versioned and not hidden,
4329 * remember it. If it is the only symbol with
4330 * this name exported by the shared object, it
4331 * will be returned as a match by the calling
4332 * function. If symbol is global (verndx < 2)
4333 * accept it unconditionally.
4335 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4336 verndx == VER_NDX_GIVEN) {
4337 result->sym_out = symp;
4340 else if (verndx >= VER_NDX_GIVEN) {
4341 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4343 if (result->vsymp == NULL)
4344 result->vsymp = symp;
4350 result->sym_out = symp;
4353 if (obj->versyms == NULL) {
4354 if (object_match_name(obj, req->ventry->name)) {
4355 _rtld_error("%s: object %s should provide version %s "
4356 "for symbol %s", obj_rtld.path, obj->path,
4357 req->ventry->name, obj->strtab + symnum);
4361 verndx = VER_NDX(obj->versyms[symnum]);
4362 if (verndx > obj->vernum) {
4363 _rtld_error("%s: symbol %s references wrong version %d",
4364 obj->path, obj->strtab + symnum, verndx);
4367 if (obj->vertab[verndx].hash != req->ventry->hash ||
4368 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4370 * Version does not match. Look if this is a
4371 * global symbol and if it is not hidden. If
4372 * global symbol (verndx < 2) is available,
4373 * use it. Do not return symbol if we are
4374 * called by dlvsym, because dlvsym looks for
4375 * a specific version and default one is not
4376 * what dlvsym wants.
4378 if ((req->flags & SYMLOOK_DLSYM) ||
4379 (verndx >= VER_NDX_GIVEN) ||
4380 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4384 result->sym_out = symp;
4389 * Search for symbol using SysV hash function.
4390 * obj->buckets is known not to be NULL at this point; the test for this was
4391 * performed with the obj->valid_hash_sysv assignment.
4394 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4396 unsigned long symnum;
4397 Sym_Match_Result matchres;
4399 matchres.sym_out = NULL;
4400 matchres.vsymp = NULL;
4401 matchres.vcount = 0;
4403 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4404 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4405 if (symnum >= obj->nchains)
4406 return (ESRCH); /* Bad object */
4408 if (matched_symbol(req, obj, &matchres, symnum)) {
4409 req->sym_out = matchres.sym_out;
4410 req->defobj_out = obj;
4414 if (matchres.vcount == 1) {
4415 req->sym_out = matchres.vsymp;
4416 req->defobj_out = obj;
4422 /* Search for symbol using GNU hash function */
4424 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4426 Elf_Addr bloom_word;
4427 const Elf32_Word *hashval;
4429 Sym_Match_Result matchres;
4430 unsigned int h1, h2;
4431 unsigned long symnum;
4433 matchres.sym_out = NULL;
4434 matchres.vsymp = NULL;
4435 matchres.vcount = 0;
4437 /* Pick right bitmask word from Bloom filter array */
4438 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4439 obj->maskwords_bm_gnu];
4441 /* Calculate modulus word size of gnu hash and its derivative */
4442 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4443 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4445 /* Filter out the "definitely not in set" queries */
4446 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4449 /* Locate hash chain and corresponding value element*/
4450 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4453 hashval = &obj->chain_zero_gnu[bucket];
4455 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4456 symnum = hashval - obj->chain_zero_gnu;
4457 if (matched_symbol(req, obj, &matchres, symnum)) {
4458 req->sym_out = matchres.sym_out;
4459 req->defobj_out = obj;
4463 } while ((*hashval++ & 1) == 0);
4464 if (matchres.vcount == 1) {
4465 req->sym_out = matchres.vsymp;
4466 req->defobj_out = obj;
4473 trace_loaded_objects(Obj_Entry *obj)
4475 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4478 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4481 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4482 fmt1 = "\t%o => %p (%x)\n";
4484 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4485 fmt2 = "\t%o (%x)\n";
4487 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4489 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4490 Needed_Entry *needed;
4496 if (list_containers && obj->needed != NULL)
4497 rtld_printf("%s:\n", obj->path);
4498 for (needed = obj->needed; needed; needed = needed->next) {
4499 if (needed->obj != NULL) {
4500 if (needed->obj->traced && !list_containers)
4502 needed->obj->traced = true;
4503 path = needed->obj->path;
4507 name = (char *)obj->strtab + needed->name;
4508 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4510 fmt = is_lib ? fmt1 : fmt2;
4511 while ((c = *fmt++) != '\0') {
4537 rtld_putstr(main_local);
4540 rtld_putstr(obj_main->path);
4547 rtld_printf("%d", sodp->sod_major);
4550 rtld_printf("%d", sodp->sod_minor);
4557 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4570 * Unload a dlopened object and its dependencies from memory and from
4571 * our data structures. It is assumed that the DAG rooted in the
4572 * object has already been unreferenced, and that the object has a
4573 * reference count of 0.
4576 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4578 Obj_Entry marker, *obj, *next;
4580 assert(root->refcount == 0);
4583 * Pass over the DAG removing unreferenced objects from
4584 * appropriate lists.
4586 unlink_object(root);
4588 /* Unmap all objects that are no longer referenced. */
4589 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4590 next = TAILQ_NEXT(obj, next);
4591 if (obj->marker || obj->refcount != 0)
4593 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4594 obj->mapsize, 0, obj->path);
4595 dbg("unloading \"%s\"", obj->path);
4597 * Unlink the object now to prevent new references from
4598 * being acquired while the bind lock is dropped in
4599 * recursive dlclose() invocations.
4601 TAILQ_REMOVE(&obj_list, obj, next);
4604 if (obj->filtees_loaded) {
4606 init_marker(&marker);
4607 TAILQ_INSERT_BEFORE(next, &marker, next);
4608 unload_filtees(obj, lockstate);
4609 next = TAILQ_NEXT(&marker, next);
4610 TAILQ_REMOVE(&obj_list, &marker, next);
4612 unload_filtees(obj, lockstate);
4614 release_object(obj);
4619 unlink_object(Obj_Entry *root)
4623 if (root->refcount == 0) {
4624 /* Remove the object from the RTLD_GLOBAL list. */
4625 objlist_remove(&list_global, root);
4627 /* Remove the object from all objects' DAG lists. */
4628 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4629 objlist_remove(&elm->obj->dldags, root);
4630 if (elm->obj != root)
4631 unlink_object(elm->obj);
4637 ref_dag(Obj_Entry *root)
4641 assert(root->dag_inited);
4642 STAILQ_FOREACH(elm, &root->dagmembers, link)
4643 elm->obj->refcount++;
4647 unref_dag(Obj_Entry *root)
4651 assert(root->dag_inited);
4652 STAILQ_FOREACH(elm, &root->dagmembers, link)
4653 elm->obj->refcount--;
4657 * Common code for MD __tls_get_addr().
4659 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4661 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4663 Elf_Addr *newdtv, *dtv;
4664 RtldLockState lockstate;
4668 /* Check dtv generation in case new modules have arrived */
4669 if (dtv[0] != tls_dtv_generation) {
4670 wlock_acquire(rtld_bind_lock, &lockstate);
4671 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4673 if (to_copy > tls_max_index)
4674 to_copy = tls_max_index;
4675 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4676 newdtv[0] = tls_dtv_generation;
4677 newdtv[1] = tls_max_index;
4679 lock_release(rtld_bind_lock, &lockstate);
4680 dtv = *dtvp = newdtv;
4683 /* Dynamically allocate module TLS if necessary */
4684 if (dtv[index + 1] == 0) {
4685 /* Signal safe, wlock will block out signals. */
4686 wlock_acquire(rtld_bind_lock, &lockstate);
4687 if (!dtv[index + 1])
4688 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4689 lock_release(rtld_bind_lock, &lockstate);
4691 return ((void *)(dtv[index + 1] + offset));
4695 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4700 /* Check dtv generation in case new modules have arrived */
4701 if (__predict_true(dtv[0] == tls_dtv_generation &&
4702 dtv[index + 1] != 0))
4703 return ((void *)(dtv[index + 1] + offset));
4704 return (tls_get_addr_slow(dtvp, index, offset));
4707 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4708 defined(__powerpc__) || defined(__riscv__)
4711 * Allocate Static TLS using the Variant I method.
4714 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4723 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4726 assert(tcbsize >= TLS_TCB_SIZE);
4727 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4728 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4730 if (oldtcb != NULL) {
4731 memcpy(tls, oldtcb, tls_static_space);
4734 /* Adjust the DTV. */
4736 for (i = 0; i < dtv[1]; i++) {
4737 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4738 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4739 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4743 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4745 dtv[0] = tls_dtv_generation;
4746 dtv[1] = tls_max_index;
4748 for (obj = globallist_curr(objs); obj != NULL;
4749 obj = globallist_next(obj)) {
4750 if (obj->tlsoffset > 0) {
4751 addr = (Elf_Addr)tls + obj->tlsoffset;
4752 if (obj->tlsinitsize > 0)
4753 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4754 if (obj->tlssize > obj->tlsinitsize)
4755 memset((void*) (addr + obj->tlsinitsize), 0,
4756 obj->tlssize - obj->tlsinitsize);
4757 dtv[obj->tlsindex + 1] = addr;
4766 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4769 Elf_Addr tlsstart, tlsend;
4772 assert(tcbsize >= TLS_TCB_SIZE);
4774 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4775 tlsend = tlsstart + tls_static_space;
4777 dtv = *(Elf_Addr **)tlsstart;
4779 for (i = 0; i < dtvsize; i++) {
4780 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4781 free((void*)dtv[i+2]);
4790 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4793 * Allocate Static TLS using the Variant II method.
4796 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4799 size_t size, ralign;
4801 Elf_Addr *dtv, *olddtv;
4802 Elf_Addr segbase, oldsegbase, addr;
4806 if (tls_static_max_align > ralign)
4807 ralign = tls_static_max_align;
4808 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4810 assert(tcbsize >= 2*sizeof(Elf_Addr));
4811 tls = malloc_aligned(size, ralign);
4812 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4814 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4815 ((Elf_Addr*)segbase)[0] = segbase;
4816 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4818 dtv[0] = tls_dtv_generation;
4819 dtv[1] = tls_max_index;
4823 * Copy the static TLS block over whole.
4825 oldsegbase = (Elf_Addr) oldtls;
4826 memcpy((void *)(segbase - tls_static_space),
4827 (const void *)(oldsegbase - tls_static_space),
4831 * If any dynamic TLS blocks have been created tls_get_addr(),
4834 olddtv = ((Elf_Addr**)oldsegbase)[1];
4835 for (i = 0; i < olddtv[1]; i++) {
4836 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4837 dtv[i+2] = olddtv[i+2];
4843 * We assume that this block was the one we created with
4844 * allocate_initial_tls().
4846 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4848 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4849 if (obj->marker || obj->tlsoffset == 0)
4851 addr = segbase - obj->tlsoffset;
4852 memset((void*) (addr + obj->tlsinitsize),
4853 0, obj->tlssize - obj->tlsinitsize);
4855 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4856 dtv[obj->tlsindex + 1] = addr;
4860 return (void*) segbase;
4864 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4867 size_t size, ralign;
4869 Elf_Addr tlsstart, tlsend;
4872 * Figure out the size of the initial TLS block so that we can
4873 * find stuff which ___tls_get_addr() allocated dynamically.
4876 if (tls_static_max_align > ralign)
4877 ralign = tls_static_max_align;
4878 size = round(tls_static_space, ralign);
4880 dtv = ((Elf_Addr**)tls)[1];
4882 tlsend = (Elf_Addr) tls;
4883 tlsstart = tlsend - size;
4884 for (i = 0; i < dtvsize; i++) {
4885 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4886 free_aligned((void *)dtv[i + 2]);
4890 free_aligned((void *)tlsstart);
4897 * Allocate TLS block for module with given index.
4900 allocate_module_tls(int index)
4905 TAILQ_FOREACH(obj, &obj_list, next) {
4908 if (obj->tlsindex == index)
4912 _rtld_error("Can't find module with TLS index %d", index);
4916 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4917 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4918 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4924 allocate_tls_offset(Obj_Entry *obj)
4931 if (obj->tlssize == 0) {
4932 obj->tls_done = true;
4936 if (tls_last_offset == 0)
4937 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4939 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4940 obj->tlssize, obj->tlsalign);
4943 * If we have already fixed the size of the static TLS block, we
4944 * must stay within that size. When allocating the static TLS, we
4945 * leave a small amount of space spare to be used for dynamically
4946 * loading modules which use static TLS.
4948 if (tls_static_space != 0) {
4949 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4951 } else if (obj->tlsalign > tls_static_max_align) {
4952 tls_static_max_align = obj->tlsalign;
4955 tls_last_offset = obj->tlsoffset = off;
4956 tls_last_size = obj->tlssize;
4957 obj->tls_done = true;
4963 free_tls_offset(Obj_Entry *obj)
4967 * If we were the last thing to allocate out of the static TLS
4968 * block, we give our space back to the 'allocator'. This is a
4969 * simplistic workaround to allow libGL.so.1 to be loaded and
4970 * unloaded multiple times.
4972 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4973 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4974 tls_last_offset -= obj->tlssize;
4980 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4983 RtldLockState lockstate;
4985 wlock_acquire(rtld_bind_lock, &lockstate);
4986 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
4988 lock_release(rtld_bind_lock, &lockstate);
4993 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4995 RtldLockState lockstate;
4997 wlock_acquire(rtld_bind_lock, &lockstate);
4998 free_tls(tcb, tcbsize, tcbalign);
4999 lock_release(rtld_bind_lock, &lockstate);
5003 object_add_name(Obj_Entry *obj, const char *name)
5009 entry = malloc(sizeof(Name_Entry) + len);
5011 if (entry != NULL) {
5012 strcpy(entry->name, name);
5013 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5018 object_match_name(const Obj_Entry *obj, const char *name)
5022 STAILQ_FOREACH(entry, &obj->names, link) {
5023 if (strcmp(name, entry->name) == 0)
5030 locate_dependency(const Obj_Entry *obj, const char *name)
5032 const Objlist_Entry *entry;
5033 const Needed_Entry *needed;
5035 STAILQ_FOREACH(entry, &list_main, link) {
5036 if (object_match_name(entry->obj, name))
5040 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5041 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5042 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5044 * If there is DT_NEEDED for the name we are looking for,
5045 * we are all set. Note that object might not be found if
5046 * dependency was not loaded yet, so the function can
5047 * return NULL here. This is expected and handled
5048 * properly by the caller.
5050 return (needed->obj);
5053 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5059 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5060 const Elf_Vernaux *vna)
5062 const Elf_Verdef *vd;
5063 const char *vername;
5065 vername = refobj->strtab + vna->vna_name;
5066 vd = depobj->verdef;
5068 _rtld_error("%s: version %s required by %s not defined",
5069 depobj->path, vername, refobj->path);
5073 if (vd->vd_version != VER_DEF_CURRENT) {
5074 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5075 depobj->path, vd->vd_version);
5078 if (vna->vna_hash == vd->vd_hash) {
5079 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5080 ((char *)vd + vd->vd_aux);
5081 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5084 if (vd->vd_next == 0)
5086 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5088 if (vna->vna_flags & VER_FLG_WEAK)
5090 _rtld_error("%s: version %s required by %s not found",
5091 depobj->path, vername, refobj->path);
5096 rtld_verify_object_versions(Obj_Entry *obj)
5098 const Elf_Verneed *vn;
5099 const Elf_Verdef *vd;
5100 const Elf_Verdaux *vda;
5101 const Elf_Vernaux *vna;
5102 const Obj_Entry *depobj;
5103 int maxvernum, vernum;
5105 if (obj->ver_checked)
5107 obj->ver_checked = true;
5111 * Walk over defined and required version records and figure out
5112 * max index used by any of them. Do very basic sanity checking
5116 while (vn != NULL) {
5117 if (vn->vn_version != VER_NEED_CURRENT) {
5118 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5119 obj->path, vn->vn_version);
5122 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
5124 vernum = VER_NEED_IDX(vna->vna_other);
5125 if (vernum > maxvernum)
5127 if (vna->vna_next == 0)
5129 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
5131 if (vn->vn_next == 0)
5133 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
5137 while (vd != NULL) {
5138 if (vd->vd_version != VER_DEF_CURRENT) {
5139 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5140 obj->path, vd->vd_version);
5143 vernum = VER_DEF_IDX(vd->vd_ndx);
5144 if (vernum > maxvernum)
5146 if (vd->vd_next == 0)
5148 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5155 * Store version information in array indexable by version index.
5156 * Verify that object version requirements are satisfied along the
5159 obj->vernum = maxvernum + 1;
5160 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5163 while (vd != NULL) {
5164 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5165 vernum = VER_DEF_IDX(vd->vd_ndx);
5166 assert(vernum <= maxvernum);
5167 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
5168 obj->vertab[vernum].hash = vd->vd_hash;
5169 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5170 obj->vertab[vernum].file = NULL;
5171 obj->vertab[vernum].flags = 0;
5173 if (vd->vd_next == 0)
5175 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5179 while (vn != NULL) {
5180 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5183 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
5185 if (check_object_provided_version(obj, depobj, vna))
5187 vernum = VER_NEED_IDX(vna->vna_other);
5188 assert(vernum <= maxvernum);
5189 obj->vertab[vernum].hash = vna->vna_hash;
5190 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5191 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5192 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5193 VER_INFO_HIDDEN : 0;
5194 if (vna->vna_next == 0)
5196 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
5198 if (vn->vn_next == 0)
5200 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
5206 rtld_verify_versions(const Objlist *objlist)
5208 Objlist_Entry *entry;
5212 STAILQ_FOREACH(entry, objlist, link) {
5214 * Skip dummy objects or objects that have their version requirements
5217 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5219 if (rtld_verify_object_versions(entry->obj) == -1) {
5221 if (ld_tracing == NULL)
5225 if (rc == 0 || ld_tracing != NULL)
5226 rc = rtld_verify_object_versions(&obj_rtld);
5231 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5236 vernum = VER_NDX(obj->versyms[symnum]);
5237 if (vernum >= obj->vernum) {
5238 _rtld_error("%s: symbol %s has wrong verneed value %d",
5239 obj->path, obj->strtab + symnum, vernum);
5240 } else if (obj->vertab[vernum].hash != 0) {
5241 return &obj->vertab[vernum];
5248 _rtld_get_stack_prot(void)
5251 return (stack_prot);
5255 _rtld_is_dlopened(void *arg)
5258 RtldLockState lockstate;
5261 rlock_acquire(rtld_bind_lock, &lockstate);
5264 obj = obj_from_addr(arg);
5266 _rtld_error("No shared object contains address");
5267 lock_release(rtld_bind_lock, &lockstate);
5270 res = obj->dlopened ? 1 : 0;
5271 lock_release(rtld_bind_lock, &lockstate);
5276 obj_remap_relro(Obj_Entry *obj, int prot)
5279 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5281 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5282 obj->path, prot, rtld_strerror(errno));
5289 obj_disable_relro(Obj_Entry *obj)
5292 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5296 obj_enforce_relro(Obj_Entry *obj)
5299 return (obj_remap_relro(obj, PROT_READ));
5303 map_stacks_exec(RtldLockState *lockstate)
5305 void (*thr_map_stacks_exec)(void);
5307 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5309 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5310 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5311 if (thr_map_stacks_exec != NULL) {
5312 stack_prot |= PROT_EXEC;
5313 thr_map_stacks_exec();
5318 symlook_init(SymLook *dst, const char *name)
5321 bzero(dst, sizeof(*dst));
5323 dst->hash = elf_hash(name);
5324 dst->hash_gnu = gnu_hash(name);
5328 symlook_init_from_req(SymLook *dst, const SymLook *src)
5331 dst->name = src->name;
5332 dst->hash = src->hash;
5333 dst->hash_gnu = src->hash_gnu;
5334 dst->ventry = src->ventry;
5335 dst->flags = src->flags;
5336 dst->defobj_out = NULL;
5337 dst->sym_out = NULL;
5338 dst->lockstate = src->lockstate;
5342 open_binary_fd(const char *argv0, bool search_in_path)
5344 char *pathenv, *pe, binpath[PATH_MAX];
5347 if (search_in_path && strchr(argv0, '/') == NULL) {
5348 pathenv = getenv("PATH");
5349 if (pathenv == NULL) {
5350 rtld_printf("-p and no PATH environment variable\n");
5353 pathenv = strdup(pathenv);
5354 if (pathenv == NULL) {
5355 rtld_printf("Cannot allocate memory\n");
5360 while ((pe = strsep(&pathenv, ":")) != NULL) {
5361 if (strlcpy(binpath, pe, sizeof(binpath)) >=
5364 if (binpath[0] != '\0' &&
5365 strlcat(binpath, "/", sizeof(binpath)) >=
5368 if (strlcat(binpath, argv0, sizeof(binpath)) >=
5371 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5372 if (fd != -1 || errno != ENOENT)
5377 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5381 rtld_printf("Opening %s: %s\n", argv0,
5382 rtld_strerror(errno));
5389 * Parse a set of command-line arguments.
5392 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp)
5395 int fd, i, j, arglen;
5398 dbg("Parsing command-line arguments");
5402 for (i = 1; i < argc; i++ ) {
5404 dbg("argv[%d]: '%s'", i, arg);
5407 * rtld arguments end with an explicit "--" or with the first
5408 * non-prefixed argument.
5410 if (strcmp(arg, "--") == 0) {
5418 * All other arguments are single-character options that can
5419 * be combined, so we need to search through `arg` for them.
5421 arglen = strlen(arg);
5422 for (j = 1; j < arglen; j++) {
5425 print_usage(argv[0]);
5427 } else if (opt == 'f') {
5429 * -f XX can be used to specify a descriptor for the
5430 * binary named at the command line (i.e., the later
5431 * argument will specify the process name but the
5432 * descriptor is what will actually be executed)
5434 if (j != arglen - 1) {
5435 /* -f must be the last option in, e.g., -abcf */
5436 _rtld_error("invalid options: %s", arg);
5440 fd = parse_integer(argv[i]);
5442 _rtld_error("invalid file descriptor: '%s'",
5448 } else if (opt == 'p') {
5451 rtld_printf("invalid argument: '%s'\n", arg);
5452 print_usage(argv[0]);
5462 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5465 parse_integer(const char *str)
5467 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5474 for (c = *str; c != '\0'; c = *++str) {
5475 if (c < '0' || c > '9')
5482 /* Make sure we actually parsed something. */
5489 print_usage(const char *argv0)
5492 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n"
5495 " -h Display this help message\n"
5496 " -p Search in PATH for named binary\n"
5497 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5498 " -- End of RTLD options\n"
5499 " <binary> Name of process to execute\n"
5500 " <args> Arguments to the executed process\n", argv0);
5504 * Overrides for libc_pic-provided functions.
5508 __getosreldate(void)
5518 oid[1] = KERN_OSRELDATE;
5520 len = sizeof(osrel);
5521 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5522 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5534 void (*__cleanup)(void);
5535 int __isthreaded = 0;
5536 int _thread_autoinit_dummy_decl = 1;
5539 * No unresolved symbols for rtld.
5542 __pthread_cxa_finalize(struct dl_phdr_info *a)
5547 __stack_chk_fail(void)
5550 _rtld_error("stack overflow detected; terminated");
5553 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5559 _rtld_error("buffer overflow detected; terminated");
5564 rtld_strerror(int errnum)
5567 if (errnum < 0 || errnum >= sys_nerr)
5568 return ("Unknown error");
5569 return (sys_errlist[errnum]);
5573 * No ifunc relocations.
5576 memset(void *dest, int c, size_t len)
5580 for (i = 0; i < len; i++)
5581 ((char *)dest)[i] = c;
5586 bzero(void *dest, size_t len)
5590 for (i = 0; i < len; i++)
5591 ((char *)dest)[i] = 0;