2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Copyright 2012 John Marino <draco@marino.st>.
8 * Copyright 2014-2017 The FreeBSD Foundation
11 * Portions of this software were developed by Konstantin Belousov
12 * under sponsorship from the FreeBSD Foundation.
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 * Dynamic linker for ELF.
38 * John Polstra <jdp@polstra.com>.
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
44 #include <sys/param.h>
45 #include <sys/mount.h>
48 #include <sys/sysctl.h>
50 #include <sys/utsname.h>
51 #include <sys/ktrace.h>
68 #include "rtld_printf.h"
69 #include "rtld_malloc.h"
70 #include "rtld_utrace.h"
74 typedef void (*func_ptr_type)(void);
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 /* Variables that cannot be static: */
79 extern struct r_debug r_debug; /* For GDB */
80 extern int _thread_autoinit_dummy_decl;
81 extern char* __progname;
82 extern void (*__cleanup)(void);
86 * Function declarations.
88 static const char *basename(const char *);
89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
90 const Elf_Dyn **, const Elf_Dyn **);
91 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
93 static void digest_dynamic(Obj_Entry *, int);
94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
95 static void distribute_static_tls(Objlist *, RtldLockState *);
96 static Obj_Entry *dlcheck(void *);
97 static int dlclose_locked(void *, RtldLockState *);
98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
99 int lo_flags, int mode, RtldLockState *lockstate);
100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
102 static bool donelist_check(DoneList *, const Obj_Entry *);
103 static void errmsg_restore(char *);
104 static char *errmsg_save(void);
105 static void *fill_search_info(const char *, size_t, void *);
106 static char *find_library(const char *, const Obj_Entry *, int *);
107 static const char *gethints(bool);
108 static void hold_object(Obj_Entry *);
109 static void unhold_object(Obj_Entry *);
110 static void init_dag(Obj_Entry *);
111 static void init_marker(Obj_Entry *);
112 static void init_pagesizes(Elf_Auxinfo **aux_info);
113 static void init_rtld(caddr_t, Elf_Auxinfo **);
114 static void initlist_add_neededs(Needed_Entry *, Objlist *);
115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
117 static void linkmap_add(Obj_Entry *);
118 static void linkmap_delete(Obj_Entry *);
119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
120 static void unload_filtees(Obj_Entry *, RtldLockState *);
121 static int load_needed_objects(Obj_Entry *, int);
122 static int load_preload_objects(void);
123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
124 static void map_stacks_exec(RtldLockState *);
125 static int obj_disable_relro(Obj_Entry *);
126 static int obj_enforce_relro(Obj_Entry *);
127 static Obj_Entry *obj_from_addr(const void *);
128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
129 static void objlist_call_init(Objlist *, RtldLockState *);
130 static void objlist_clear(Objlist *);
131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
132 static void objlist_init(Objlist *);
133 static void objlist_push_head(Objlist *, Obj_Entry *);
134 static void objlist_push_tail(Objlist *, Obj_Entry *);
135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
136 static void objlist_remove(Objlist *, Obj_Entry *);
137 static int open_binary_fd(const char *argv0, bool search_in_path);
138 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp);
139 static int parse_integer(const char *);
140 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
141 static void print_usage(const char *argv0);
142 static void release_object(Obj_Entry *);
143 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
144 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
145 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
146 int flags, RtldLockState *lockstate);
147 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
149 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
150 static int rtld_dirname(const char *, char *);
151 static int rtld_dirname_abs(const char *, char *);
152 static void *rtld_dlopen(const char *name, int fd, int mode);
153 static void rtld_exit(void);
154 static char *search_library_path(const char *, const char *, const char *,
156 static char *search_library_pathfds(const char *, const char *, int *);
157 static const void **get_program_var_addr(const char *, RtldLockState *);
158 static void set_program_var(const char *, const void *);
159 static int symlook_default(SymLook *, const Obj_Entry *refobj);
160 static int symlook_global(SymLook *, DoneList *);
161 static void symlook_init_from_req(SymLook *, const SymLook *);
162 static int symlook_list(SymLook *, const Objlist *, DoneList *);
163 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
164 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
165 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
166 static void trace_loaded_objects(Obj_Entry *);
167 static void unlink_object(Obj_Entry *);
168 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
169 static void unref_dag(Obj_Entry *);
170 static void ref_dag(Obj_Entry *);
171 static char *origin_subst_one(Obj_Entry *, char *, const char *,
173 static char *origin_subst(Obj_Entry *, const char *);
174 static bool obj_resolve_origin(Obj_Entry *obj);
175 static void preinit_main(void);
176 static int rtld_verify_versions(const Objlist *);
177 static int rtld_verify_object_versions(Obj_Entry *);
178 static void object_add_name(Obj_Entry *, const char *);
179 static int object_match_name(const Obj_Entry *, const char *);
180 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
181 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
182 struct dl_phdr_info *phdr_info);
183 static uint32_t gnu_hash(const char *);
184 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
185 const unsigned long);
187 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
188 void _r_debug_postinit(struct link_map *) __noinline __exported;
190 int __sys_openat(int, const char *, int, ...);
195 static char *error_message; /* Message for dlerror(), or NULL */
196 struct r_debug r_debug __exported; /* for GDB; */
197 static bool libmap_disable; /* Disable libmap */
198 static bool ld_loadfltr; /* Immediate filters processing */
199 static char *libmap_override; /* Maps to use in addition to libmap.conf */
200 static bool trust; /* False for setuid and setgid programs */
201 static bool dangerous_ld_env; /* True if environment variables have been
202 used to affect the libraries loaded */
203 bool ld_bind_not; /* Disable PLT update */
204 static char *ld_bind_now; /* Environment variable for immediate binding */
205 static char *ld_debug; /* Environment variable for debugging */
206 static char *ld_library_path; /* Environment variable for search path */
207 static char *ld_library_dirs; /* Environment variable for library descriptors */
208 static char *ld_preload; /* Environment variable for libraries to
210 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
211 static const char *ld_tracing; /* Called from ldd to print libs */
212 static char *ld_utrace; /* Use utrace() to log events. */
213 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
214 static Obj_Entry *obj_main; /* The main program shared object */
215 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
216 static unsigned int obj_count; /* Number of objects in obj_list */
217 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
219 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
220 STAILQ_HEAD_INITIALIZER(list_global);
221 static Objlist list_main = /* Objects loaded at program startup */
222 STAILQ_HEAD_INITIALIZER(list_main);
223 static Objlist list_fini = /* Objects needing fini() calls */
224 STAILQ_HEAD_INITIALIZER(list_fini);
226 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
228 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
230 extern Elf_Dyn _DYNAMIC;
231 #pragma weak _DYNAMIC
233 int dlclose(void *) __exported;
234 char *dlerror(void) __exported;
235 void *dlopen(const char *, int) __exported;
236 void *fdlopen(int, int) __exported;
237 void *dlsym(void *, const char *) __exported;
238 dlfunc_t dlfunc(void *, const char *) __exported;
239 void *dlvsym(void *, const char *, const char *) __exported;
240 int dladdr(const void *, Dl_info *) __exported;
241 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
242 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
243 int dlinfo(void *, int , void *) __exported;
244 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
245 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
246 int _rtld_get_stack_prot(void) __exported;
247 int _rtld_is_dlopened(void *) __exported;
248 void _rtld_error(const char *, ...) __exported;
250 /* Only here to fix -Wmissing-prototypes warnings */
251 int __getosreldate(void);
252 void __pthread_cxa_finalize(struct dl_phdr_info *a);
253 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
254 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
258 static int osreldate;
261 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
262 static int max_stack_flags;
265 * Global declarations normally provided by crt1. The dynamic linker is
266 * not built with crt1, so we have to provide them ourselves.
272 * Used to pass argc, argv to init functions.
278 * Globals to control TLS allocation.
280 size_t tls_last_offset; /* Static TLS offset of last module */
281 size_t tls_last_size; /* Static TLS size of last module */
282 size_t tls_static_space; /* Static TLS space allocated */
283 static size_t tls_static_max_align;
284 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
285 int tls_max_index = 1; /* Largest module index allocated */
287 static bool ld_library_path_rpath = false;
290 * Globals for path names, and such
292 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
293 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
294 const char *ld_path_rtld = _PATH_RTLD;
295 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
296 const char *ld_env_prefix = LD_;
299 * Fill in a DoneList with an allocation large enough to hold all of
300 * the currently-loaded objects. Keep this as a macro since it calls
301 * alloca and we want that to occur within the scope of the caller.
303 #define donelist_init(dlp) \
304 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
305 assert((dlp)->objs != NULL), \
306 (dlp)->num_alloc = obj_count, \
309 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
310 if (ld_utrace != NULL) \
311 ld_utrace_log(e, h, mb, ms, r, n); \
315 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
316 int refcnt, const char *name)
318 struct utrace_rtld ut;
319 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
321 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
324 ut.mapbase = mapbase;
325 ut.mapsize = mapsize;
327 bzero(ut.name, sizeof(ut.name));
329 strlcpy(ut.name, name, sizeof(ut.name));
330 utrace(&ut, sizeof(ut));
333 #ifdef RTLD_VARIANT_ENV_NAMES
335 * construct the env variable based on the type of binary that's
338 static inline const char *
341 static char buffer[128];
343 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
344 strlcat(buffer, var, sizeof(buffer));
352 * Main entry point for dynamic linking. The first argument is the
353 * stack pointer. The stack is expected to be laid out as described
354 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
355 * Specifically, the stack pointer points to a word containing
356 * ARGC. Following that in the stack is a null-terminated sequence
357 * of pointers to argument strings. Then comes a null-terminated
358 * sequence of pointers to environment strings. Finally, there is a
359 * sequence of "auxiliary vector" entries.
361 * The second argument points to a place to store the dynamic linker's
362 * exit procedure pointer and the third to a place to store the main
365 * The return value is the main program's entry point.
368 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
370 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
371 Objlist_Entry *entry;
372 Obj_Entry *last_interposer, *obj, *preload_tail;
373 const Elf_Phdr *phdr;
375 RtldLockState lockstate;
378 char **argv, **env, **envp, *kexecpath, *library_path_rpath;
381 char buf[MAXPATHLEN];
382 int argc, fd, i, phnum, rtld_argc;
383 bool dir_enable, explicit_fd, search_in_path;
386 * On entry, the dynamic linker itself has not been relocated yet.
387 * Be very careful not to reference any global data until after
388 * init_rtld has returned. It is OK to reference file-scope statics
389 * and string constants, and to call static and global functions.
392 /* Find the auxiliary vector on the stack. */
396 sp += argc + 1; /* Skip over arguments and NULL terminator */
398 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
400 aux = (Elf_Auxinfo *) sp;
402 /* Digest the auxiliary vector. */
403 for (i = 0; i < AT_COUNT; i++)
405 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
406 if (auxp->a_type < AT_COUNT)
407 aux_info[auxp->a_type] = auxp;
410 /* Initialize and relocate ourselves. */
411 assert(aux_info[AT_BASE] != NULL);
412 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
414 __progname = obj_rtld.path;
415 argv0 = argv[0] != NULL ? argv[0] : "(null)";
420 trust = !issetugid();
422 md_abi_variant_hook(aux_info);
425 if (aux_info[AT_EXECFD] != NULL) {
426 fd = aux_info[AT_EXECFD]->a_un.a_val;
428 assert(aux_info[AT_PHDR] != NULL);
429 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
430 if (phdr == obj_rtld.phdr) {
432 _rtld_error("Tainted process refusing to run binary %s",
436 dbg("opening main program in direct exec mode");
438 rtld_argc = parse_args(argv, argc, &search_in_path, &fd);
439 argv0 = argv[rtld_argc];
440 explicit_fd = (fd != -1);
442 fd = open_binary_fd(argv0, search_in_path);
443 if (fstat(fd, &st) == -1) {
444 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
445 explicit_fd ? "user-provided descriptor" : argv0,
446 rtld_strerror(errno));
451 * Rough emulation of the permission checks done by
452 * execve(2), only Unix DACs are checked, ACLs are
453 * ignored. Preserve the semantic of disabling owner
454 * to execute if owner x bit is cleared, even if
455 * others x bit is enabled.
456 * mmap(2) does not allow to mmap with PROT_EXEC if
457 * binary' file comes from noexec mount. We cannot
458 * set VV_TEXT on the binary.
461 if (st.st_uid == geteuid()) {
462 if ((st.st_mode & S_IXUSR) != 0)
464 } else if (st.st_gid == getegid()) {
465 if ((st.st_mode & S_IXGRP) != 0)
467 } else if ((st.st_mode & S_IXOTH) != 0) {
471 _rtld_error("No execute permission for binary %s",
477 * For direct exec mode, argv[0] is the interpreter
478 * name, we must remove it and shift arguments left
479 * before invoking binary main. Since stack layout
480 * places environment pointers and aux vectors right
481 * after the terminating NULL, we must shift
482 * environment and aux as well.
484 main_argc = argc - rtld_argc;
485 for (i = 0; i <= main_argc; i++)
486 argv[i] = argv[i + rtld_argc];
488 environ = env = envp = argv + main_argc + 1;
490 *envp = *(envp + rtld_argc);
492 } while (*envp != NULL);
493 aux = auxp = (Elf_Auxinfo *)envp;
494 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
495 for (;; auxp++, auxpf++) {
497 if (auxp->a_type == AT_NULL)
501 _rtld_error("No binary");
507 ld_bind_now = getenv(_LD("BIND_NOW"));
510 * If the process is tainted, then we un-set the dangerous environment
511 * variables. The process will be marked as tainted until setuid(2)
512 * is called. If any child process calls setuid(2) we do not want any
513 * future processes to honor the potentially un-safe variables.
516 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
517 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
518 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
519 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
520 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
521 _rtld_error("environment corrupt; aborting");
525 ld_debug = getenv(_LD("DEBUG"));
526 if (ld_bind_now == NULL)
527 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
528 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
529 libmap_override = getenv(_LD("LIBMAP"));
530 ld_library_path = getenv(_LD("LIBRARY_PATH"));
531 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
532 ld_preload = getenv(_LD("PRELOAD"));
533 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
534 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
535 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
536 if (library_path_rpath != NULL) {
537 if (library_path_rpath[0] == 'y' ||
538 library_path_rpath[0] == 'Y' ||
539 library_path_rpath[0] == '1')
540 ld_library_path_rpath = true;
542 ld_library_path_rpath = false;
544 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
545 (ld_library_path != NULL) || (ld_preload != NULL) ||
546 (ld_elf_hints_path != NULL) || ld_loadfltr;
547 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
548 ld_utrace = getenv(_LD("UTRACE"));
550 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
551 ld_elf_hints_path = ld_elf_hints_default;
553 if (ld_debug != NULL && *ld_debug != '\0')
555 dbg("%s is initialized, base address = %p", __progname,
556 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
557 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
558 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
560 dbg("initializing thread locks");
564 * Load the main program, or process its program header if it is
567 if (fd != -1) { /* Load the main program. */
568 dbg("loading main program");
569 obj_main = map_object(fd, argv0, NULL);
571 if (obj_main == NULL)
573 max_stack_flags = obj_main->stack_flags;
574 } else { /* Main program already loaded. */
575 dbg("processing main program's program header");
576 assert(aux_info[AT_PHDR] != NULL);
577 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
578 assert(aux_info[AT_PHNUM] != NULL);
579 phnum = aux_info[AT_PHNUM]->a_un.a_val;
580 assert(aux_info[AT_PHENT] != NULL);
581 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
582 assert(aux_info[AT_ENTRY] != NULL);
583 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
584 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
588 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
589 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
590 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
591 if (kexecpath[0] == '/')
592 obj_main->path = kexecpath;
593 else if (getcwd(buf, sizeof(buf)) == NULL ||
594 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
595 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
596 obj_main->path = xstrdup(argv0);
598 obj_main->path = xstrdup(buf);
600 dbg("No AT_EXECPATH or direct exec");
601 obj_main->path = xstrdup(argv0);
603 dbg("obj_main path %s", obj_main->path);
604 obj_main->mainprog = true;
606 if (aux_info[AT_STACKPROT] != NULL &&
607 aux_info[AT_STACKPROT]->a_un.a_val != 0)
608 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
612 * Get the actual dynamic linker pathname from the executable if
613 * possible. (It should always be possible.) That ensures that
614 * gdb will find the right dynamic linker even if a non-standard
617 if (obj_main->interp != NULL &&
618 strcmp(obj_main->interp, obj_rtld.path) != 0) {
620 obj_rtld.path = xstrdup(obj_main->interp);
621 __progname = obj_rtld.path;
625 digest_dynamic(obj_main, 0);
626 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
627 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
628 obj_main->dynsymcount);
630 linkmap_add(obj_main);
631 linkmap_add(&obj_rtld);
633 /* Link the main program into the list of objects. */
634 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
638 /* Initialize a fake symbol for resolving undefined weak references. */
639 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
640 sym_zero.st_shndx = SHN_UNDEF;
641 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
644 libmap_disable = (bool)lm_init(libmap_override);
646 dbg("loading LD_PRELOAD libraries");
647 if (load_preload_objects() == -1)
649 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
651 dbg("loading needed objects");
652 if (load_needed_objects(obj_main, 0) == -1)
655 /* Make a list of all objects loaded at startup. */
656 last_interposer = obj_main;
657 TAILQ_FOREACH(obj, &obj_list, next) {
660 if (obj->z_interpose && obj != obj_main) {
661 objlist_put_after(&list_main, last_interposer, obj);
662 last_interposer = obj;
664 objlist_push_tail(&list_main, obj);
669 dbg("checking for required versions");
670 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
673 if (ld_tracing) { /* We're done */
674 trace_loaded_objects(obj_main);
678 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
679 dump_relocations(obj_main);
684 * Processing tls relocations requires having the tls offsets
685 * initialized. Prepare offsets before starting initial
686 * relocation processing.
688 dbg("initializing initial thread local storage offsets");
689 STAILQ_FOREACH(entry, &list_main, link) {
691 * Allocate all the initial objects out of the static TLS
692 * block even if they didn't ask for it.
694 allocate_tls_offset(entry->obj);
697 if (relocate_objects(obj_main,
698 ld_bind_now != NULL && *ld_bind_now != '\0',
699 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
702 dbg("doing copy relocations");
703 if (do_copy_relocations(obj_main) == -1)
706 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
707 dump_relocations(obj_main);
714 * Setup TLS for main thread. This must be done after the
715 * relocations are processed, since tls initialization section
716 * might be the subject for relocations.
718 dbg("initializing initial thread local storage");
719 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
721 dbg("initializing key program variables");
722 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
723 set_program_var("environ", env);
724 set_program_var("__elf_aux_vector", aux);
726 /* Make a list of init functions to call. */
727 objlist_init(&initlist);
728 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
729 preload_tail, &initlist);
731 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
733 map_stacks_exec(NULL);
735 if (!obj_main->crt_no_init) {
737 * Make sure we don't call the main program's init and fini
738 * functions for binaries linked with old crt1 which calls
741 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
742 obj_main->preinit_array = obj_main->init_array =
743 obj_main->fini_array = (Elf_Addr)NULL;
747 * Execute MD initializers required before we call the objects'
752 wlock_acquire(rtld_bind_lock, &lockstate);
754 dbg("resolving ifuncs");
755 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
756 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
759 if (obj_main->crt_no_init)
761 objlist_call_init(&initlist, &lockstate);
762 _r_debug_postinit(&obj_main->linkmap);
763 objlist_clear(&initlist);
764 dbg("loading filtees");
765 TAILQ_FOREACH(obj, &obj_list, next) {
768 if (ld_loadfltr || obj->z_loadfltr)
769 load_filtees(obj, 0, &lockstate);
772 dbg("enforcing main obj relro");
773 if (obj_enforce_relro(obj_main) == -1)
776 lock_release(rtld_bind_lock, &lockstate);
778 dbg("transferring control to program entry point = %p", obj_main->entry);
780 /* Return the exit procedure and the program entry point. */
781 *exit_proc = rtld_exit;
783 return (func_ptr_type) obj_main->entry;
787 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
792 ptr = (void *)make_function_pointer(def, obj);
793 target = call_ifunc_resolver(ptr);
794 return ((void *)target);
798 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
799 * Changes to this function should be applied there as well.
802 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
806 const Obj_Entry *defobj;
809 RtldLockState lockstate;
811 rlock_acquire(rtld_bind_lock, &lockstate);
812 if (sigsetjmp(lockstate.env, 0) != 0)
813 lock_upgrade(rtld_bind_lock, &lockstate);
815 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
817 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
819 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
820 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
824 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
825 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
827 target = (Elf_Addr)(defobj->relocbase + def->st_value);
829 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
830 defobj->strtab + def->st_name, basename(obj->path),
831 (void *)target, basename(defobj->path));
834 * Write the new contents for the jmpslot. Note that depending on
835 * architecture, the value which we need to return back to the
836 * lazy binding trampoline may or may not be the target
837 * address. The value returned from reloc_jmpslot() is the value
838 * that the trampoline needs.
840 target = reloc_jmpslot(where, target, defobj, obj, rel);
841 lock_release(rtld_bind_lock, &lockstate);
846 * Error reporting function. Use it like printf. If formats the message
847 * into a buffer, and sets things up so that the next call to dlerror()
848 * will return the message.
851 _rtld_error(const char *fmt, ...)
853 static char buf[512];
857 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
860 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
864 * Return a dynamically-allocated copy of the current error message, if any.
869 return error_message == NULL ? NULL : xstrdup(error_message);
873 * Restore the current error message from a copy which was previously saved
874 * by errmsg_save(). The copy is freed.
877 errmsg_restore(char *saved_msg)
879 if (saved_msg == NULL)
880 error_message = NULL;
882 _rtld_error("%s", saved_msg);
888 basename(const char *name)
890 const char *p = strrchr(name, '/');
891 return p != NULL ? p + 1 : name;
894 static struct utsname uts;
897 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
898 const char *subst, bool may_free)
900 char *p, *p1, *res, *resp;
901 int subst_len, kw_len, subst_count, old_len, new_len;
906 * First, count the number of the keyword occurrences, to
907 * preallocate the final string.
909 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
916 * If the keyword is not found, just return.
918 * Return non-substituted string if resolution failed. We
919 * cannot do anything more reasonable, the failure mode of the
920 * caller is unresolved library anyway.
922 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
923 return (may_free ? real : xstrdup(real));
925 subst = obj->origin_path;
928 * There is indeed something to substitute. Calculate the
929 * length of the resulting string, and allocate it.
931 subst_len = strlen(subst);
932 old_len = strlen(real);
933 new_len = old_len + (subst_len - kw_len) * subst_count;
934 res = xmalloc(new_len + 1);
937 * Now, execute the substitution loop.
939 for (p = real, resp = res, *resp = '\0';;) {
942 /* Copy the prefix before keyword. */
943 memcpy(resp, p, p1 - p);
945 /* Keyword replacement. */
946 memcpy(resp, subst, subst_len);
954 /* Copy to the end of string and finish. */
962 origin_subst(Obj_Entry *obj, const char *real)
964 char *res1, *res2, *res3, *res4;
966 if (obj == NULL || !trust)
967 return (xstrdup(real));
968 if (uts.sysname[0] == '\0') {
969 if (uname(&uts) != 0) {
970 _rtld_error("utsname failed: %d", errno);
974 /* __DECONST is safe here since without may_free real is unchanged */
975 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL,
977 res2 = origin_subst_one(NULL, res1, "$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, _BASENAME_RTLD ": ");
991 rtld_fdputstr(STDERR_FILENO, msg);
992 rtld_fdputchar(STDERR_FILENO, '\n');
997 * Process a shared object's DYNAMIC section, and save the important
998 * information in its Obj_Entry structure.
1001 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1002 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1004 const Elf_Dyn *dynp;
1005 Needed_Entry **needed_tail = &obj->needed;
1006 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1007 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1008 const Elf_Hashelt *hashtab;
1009 const Elf32_Word *hashval;
1010 Elf32_Word bkt, nmaskwords;
1012 int plttype = DT_REL;
1016 *dyn_runpath = NULL;
1018 obj->bind_now = false;
1019 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
1020 switch (dynp->d_tag) {
1023 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1027 obj->relsize = dynp->d_un.d_val;
1031 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1035 obj->pltrel = (const Elf_Rel *)
1036 (obj->relocbase + dynp->d_un.d_ptr);
1040 obj->pltrelsize = dynp->d_un.d_val;
1044 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1048 obj->relasize = dynp->d_un.d_val;
1052 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1056 plttype = dynp->d_un.d_val;
1057 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1061 obj->symtab = (const Elf_Sym *)
1062 (obj->relocbase + dynp->d_un.d_ptr);
1066 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1070 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1074 obj->strsize = dynp->d_un.d_val;
1078 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1083 obj->verneednum = dynp->d_un.d_val;
1087 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1092 obj->verdefnum = dynp->d_un.d_val;
1096 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1102 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1104 obj->nbuckets = hashtab[0];
1105 obj->nchains = hashtab[1];
1106 obj->buckets = hashtab + 2;
1107 obj->chains = obj->buckets + obj->nbuckets;
1108 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1109 obj->buckets != NULL;
1115 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1117 obj->nbuckets_gnu = hashtab[0];
1118 obj->symndx_gnu = hashtab[1];
1119 nmaskwords = hashtab[2];
1120 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1121 obj->maskwords_bm_gnu = nmaskwords - 1;
1122 obj->shift2_gnu = hashtab[3];
1123 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1124 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1125 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1127 /* Number of bitmask words is required to be power of 2 */
1128 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1129 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1135 Needed_Entry *nep = NEW(Needed_Entry);
1136 nep->name = dynp->d_un.d_val;
1141 needed_tail = &nep->next;
1147 Needed_Entry *nep = NEW(Needed_Entry);
1148 nep->name = dynp->d_un.d_val;
1152 *needed_filtees_tail = nep;
1153 needed_filtees_tail = &nep->next;
1159 Needed_Entry *nep = NEW(Needed_Entry);
1160 nep->name = dynp->d_un.d_val;
1164 *needed_aux_filtees_tail = nep;
1165 needed_aux_filtees_tail = &nep->next;
1170 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1174 obj->textrel = true;
1178 obj->symbolic = true;
1183 * We have to wait until later to process this, because we
1184 * might not have gotten the address of the string table yet.
1194 *dyn_runpath = dynp;
1198 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1201 case DT_PREINIT_ARRAY:
1202 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1205 case DT_PREINIT_ARRAYSZ:
1206 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1210 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1213 case DT_INIT_ARRAYSZ:
1214 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1218 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1222 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1225 case DT_FINI_ARRAYSZ:
1226 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1230 * Don't process DT_DEBUG on MIPS as the dynamic section
1231 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1237 dbg("Filling in DT_DEBUG entry");
1238 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1243 if (dynp->d_un.d_val & DF_ORIGIN)
1244 obj->z_origin = true;
1245 if (dynp->d_un.d_val & DF_SYMBOLIC)
1246 obj->symbolic = true;
1247 if (dynp->d_un.d_val & DF_TEXTREL)
1248 obj->textrel = true;
1249 if (dynp->d_un.d_val & DF_BIND_NOW)
1250 obj->bind_now = true;
1251 if (dynp->d_un.d_val & DF_STATIC_TLS)
1252 obj->static_tls = true;
1255 case DT_MIPS_LOCAL_GOTNO:
1256 obj->local_gotno = dynp->d_un.d_val;
1259 case DT_MIPS_SYMTABNO:
1260 obj->symtabno = dynp->d_un.d_val;
1263 case DT_MIPS_GOTSYM:
1264 obj->gotsym = dynp->d_un.d_val;
1267 case DT_MIPS_RLD_MAP:
1268 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1271 case DT_MIPS_PLTGOT:
1272 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase +
1278 #ifdef __powerpc64__
1279 case DT_PPC64_GLINK:
1280 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1285 if (dynp->d_un.d_val & DF_1_NOOPEN)
1286 obj->z_noopen = true;
1287 if (dynp->d_un.d_val & DF_1_ORIGIN)
1288 obj->z_origin = true;
1289 if (dynp->d_un.d_val & DF_1_GLOBAL)
1290 obj->z_global = true;
1291 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1292 obj->bind_now = true;
1293 if (dynp->d_un.d_val & DF_1_NODELETE)
1294 obj->z_nodelete = true;
1295 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1296 obj->z_loadfltr = true;
1297 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1298 obj->z_interpose = true;
1299 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1300 obj->z_nodeflib = true;
1305 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1312 obj->traced = false;
1314 if (plttype == DT_RELA) {
1315 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1317 obj->pltrelasize = obj->pltrelsize;
1318 obj->pltrelsize = 0;
1321 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1322 if (obj->valid_hash_sysv)
1323 obj->dynsymcount = obj->nchains;
1324 else if (obj->valid_hash_gnu) {
1325 obj->dynsymcount = 0;
1326 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1327 if (obj->buckets_gnu[bkt] == 0)
1329 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1332 while ((*hashval++ & 1u) == 0);
1334 obj->dynsymcount += obj->symndx_gnu;
1339 obj_resolve_origin(Obj_Entry *obj)
1342 if (obj->origin_path != NULL)
1344 obj->origin_path = xmalloc(PATH_MAX);
1345 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1349 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1350 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1353 if (obj->z_origin && !obj_resolve_origin(obj))
1356 if (dyn_runpath != NULL) {
1357 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1358 obj->runpath = origin_subst(obj, obj->runpath);
1359 } else if (dyn_rpath != NULL) {
1360 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1361 obj->rpath = origin_subst(obj, obj->rpath);
1363 if (dyn_soname != NULL)
1364 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1368 digest_dynamic(Obj_Entry *obj, int early)
1370 const Elf_Dyn *dyn_rpath;
1371 const Elf_Dyn *dyn_soname;
1372 const Elf_Dyn *dyn_runpath;
1374 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1375 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1379 * Process a shared object's program header. This is used only for the
1380 * main program, when the kernel has already loaded the main program
1381 * into memory before calling the dynamic linker. It creates and
1382 * returns an Obj_Entry structure.
1385 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1388 const Elf_Phdr *phlimit = phdr + phnum;
1390 Elf_Addr note_start, note_end;
1394 for (ph = phdr; ph < phlimit; ph++) {
1395 if (ph->p_type != PT_PHDR)
1399 obj->phsize = ph->p_memsz;
1400 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1404 obj->stack_flags = PF_X | PF_R | PF_W;
1406 for (ph = phdr; ph < phlimit; ph++) {
1407 switch (ph->p_type) {
1410 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1414 if (nsegs == 0) { /* First load segment */
1415 obj->vaddrbase = trunc_page(ph->p_vaddr);
1416 obj->mapbase = obj->vaddrbase + obj->relocbase;
1417 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1419 } else { /* Last load segment */
1420 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1427 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1432 obj->tlssize = ph->p_memsz;
1433 obj->tlsalign = ph->p_align;
1434 obj->tlsinitsize = ph->p_filesz;
1435 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1439 obj->stack_flags = ph->p_flags;
1443 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1444 obj->relro_size = round_page(ph->p_memsz);
1448 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1449 note_end = note_start + ph->p_filesz;
1450 digest_notes(obj, note_start, note_end);
1455 _rtld_error("%s: too few PT_LOAD segments", path);
1464 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1466 const Elf_Note *note;
1467 const char *note_name;
1470 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1471 note = (const Elf_Note *)((const char *)(note + 1) +
1472 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1473 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1474 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1475 note->n_descsz != sizeof(int32_t))
1477 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1478 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1479 note->n_type != NT_FREEBSD_NOINIT_TAG)
1481 note_name = (const char *)(note + 1);
1482 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1483 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1485 switch (note->n_type) {
1486 case NT_FREEBSD_ABI_TAG:
1487 /* FreeBSD osrel note */
1488 p = (uintptr_t)(note + 1);
1489 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1490 obj->osrel = *(const int32_t *)(p);
1491 dbg("note osrel %d", obj->osrel);
1493 case NT_FREEBSD_FEATURE_CTL:
1494 /* FreeBSD ABI feature control note */
1495 p = (uintptr_t)(note + 1);
1496 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1497 obj->fctl0 = *(const uint32_t *)(p);
1498 dbg("note fctl0 %#x", obj->fctl0);
1500 case NT_FREEBSD_NOINIT_TAG:
1501 /* FreeBSD 'crt does not call init' note */
1502 obj->crt_no_init = true;
1503 dbg("note crt_no_init");
1510 dlcheck(void *handle)
1514 TAILQ_FOREACH(obj, &obj_list, next) {
1515 if (obj == (Obj_Entry *) handle)
1519 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1520 _rtld_error("Invalid shared object handle %p", handle);
1527 * If the given object is already in the donelist, return true. Otherwise
1528 * add the object to the list and return false.
1531 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1535 for (i = 0; i < dlp->num_used; i++)
1536 if (dlp->objs[i] == obj)
1539 * Our donelist allocation should always be sufficient. But if
1540 * our threads locking isn't working properly, more shared objects
1541 * could have been loaded since we allocated the list. That should
1542 * never happen, but we'll handle it properly just in case it does.
1544 if (dlp->num_used < dlp->num_alloc)
1545 dlp->objs[dlp->num_used++] = obj;
1550 * Hash function for symbol table lookup. Don't even think about changing
1551 * this. It is specified by the System V ABI.
1554 elf_hash(const char *name)
1556 const unsigned char *p = (const unsigned char *) name;
1557 unsigned long h = 0;
1560 while (*p != '\0') {
1561 h = (h << 4) + *p++;
1562 if ((g = h & 0xf0000000) != 0)
1570 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1571 * unsigned in case it's implemented with a wider type.
1574 gnu_hash(const char *s)
1580 for (c = *s; c != '\0'; c = *++s)
1582 return (h & 0xffffffff);
1587 * Find the library with the given name, and return its full pathname.
1588 * The returned string is dynamically allocated. Generates an error
1589 * message and returns NULL if the library cannot be found.
1591 * If the second argument is non-NULL, then it refers to an already-
1592 * loaded shared object, whose library search path will be searched.
1594 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1595 * descriptor (which is close-on-exec) will be passed out via the third
1598 * The search order is:
1599 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1600 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1602 * DT_RUNPATH in the referencing file
1603 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1605 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1607 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1610 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1612 char *pathname, *refobj_path;
1614 bool nodeflib, objgiven;
1616 objgiven = refobj != NULL;
1618 if (libmap_disable || !objgiven ||
1619 (name = lm_find(refobj->path, xname)) == NULL)
1622 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1623 if (name[0] != '/' && !trust) {
1624 _rtld_error("Absolute pathname required "
1625 "for shared object \"%s\"", name);
1628 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1629 __DECONST(char *, name)));
1632 dbg(" Searching for \"%s\"", name);
1633 refobj_path = objgiven ? refobj->path : NULL;
1636 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1637 * back to pre-conforming behaviour if user requested so with
1638 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1641 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1642 pathname = search_library_path(name, ld_library_path,
1644 if (pathname != NULL)
1646 if (refobj != NULL) {
1647 pathname = search_library_path(name, refobj->rpath,
1649 if (pathname != NULL)
1652 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1653 if (pathname != NULL)
1655 pathname = search_library_path(name, gethints(false),
1657 if (pathname != NULL)
1659 pathname = search_library_path(name, ld_standard_library_path,
1661 if (pathname != NULL)
1664 nodeflib = objgiven ? refobj->z_nodeflib : false;
1666 pathname = search_library_path(name, refobj->rpath,
1668 if (pathname != NULL)
1671 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1672 pathname = search_library_path(name, obj_main->rpath,
1674 if (pathname != NULL)
1677 pathname = search_library_path(name, ld_library_path,
1679 if (pathname != NULL)
1682 pathname = search_library_path(name, refobj->runpath,
1684 if (pathname != NULL)
1687 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1688 if (pathname != NULL)
1690 pathname = search_library_path(name, gethints(nodeflib),
1692 if (pathname != NULL)
1694 if (objgiven && !nodeflib) {
1695 pathname = search_library_path(name,
1696 ld_standard_library_path, refobj_path, fdp);
1697 if (pathname != NULL)
1702 if (objgiven && refobj->path != NULL) {
1703 _rtld_error("Shared object \"%s\" not found, "
1704 "required by \"%s\"", name, basename(refobj->path));
1706 _rtld_error("Shared object \"%s\" not found", name);
1712 * Given a symbol number in a referencing object, find the corresponding
1713 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1714 * no definition was found. Returns a pointer to the Obj_Entry of the
1715 * defining object via the reference parameter DEFOBJ_OUT.
1718 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1719 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1720 RtldLockState *lockstate)
1724 const Obj_Entry *defobj;
1725 const Ver_Entry *ve;
1731 * If we have already found this symbol, get the information from
1734 if (symnum >= refobj->dynsymcount)
1735 return NULL; /* Bad object */
1736 if (cache != NULL && cache[symnum].sym != NULL) {
1737 *defobj_out = cache[symnum].obj;
1738 return cache[symnum].sym;
1741 ref = refobj->symtab + symnum;
1742 name = refobj->strtab + ref->st_name;
1748 * We don't have to do a full scale lookup if the symbol is local.
1749 * We know it will bind to the instance in this load module; to
1750 * which we already have a pointer (ie ref). By not doing a lookup,
1751 * we not only improve performance, but it also avoids unresolvable
1752 * symbols when local symbols are not in the hash table. This has
1753 * been seen with the ia64 toolchain.
1755 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1756 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1757 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1760 symlook_init(&req, name);
1762 ve = req.ventry = fetch_ventry(refobj, symnum);
1763 req.lockstate = lockstate;
1764 res = symlook_default(&req, refobj);
1767 defobj = req.defobj_out;
1775 * If we found no definition and the reference is weak, treat the
1776 * symbol as having the value zero.
1778 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1784 *defobj_out = defobj;
1785 /* Record the information in the cache to avoid subsequent lookups. */
1786 if (cache != NULL) {
1787 cache[symnum].sym = def;
1788 cache[symnum].obj = defobj;
1791 if (refobj != &obj_rtld)
1792 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1793 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1799 * Return the search path from the ldconfig hints file, reading it if
1800 * necessary. If nostdlib is true, then the default search paths are
1801 * not added to result.
1803 * Returns NULL if there are problems with the hints file,
1804 * or if the search path there is empty.
1807 gethints(bool nostdlib)
1809 static char *filtered_path;
1810 static const char *hints;
1811 static struct elfhints_hdr hdr;
1812 struct fill_search_info_args sargs, hargs;
1813 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1814 struct dl_serpath *SLPpath, *hintpath;
1816 struct stat hint_stat;
1817 unsigned int SLPndx, hintndx, fndx, fcount;
1823 /* First call, read the hints file */
1824 if (hints == NULL) {
1825 /* Keep from trying again in case the hints file is bad. */
1828 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1832 * Check of hdr.dirlistlen value against type limit
1833 * intends to pacify static analyzers. Further
1834 * paranoia leads to checks that dirlist is fully
1835 * contained in the file range.
1837 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1838 hdr.magic != ELFHINTS_MAGIC ||
1839 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1840 fstat(fd, &hint_stat) == -1) {
1847 if (dl + hdr.dirlist < dl)
1850 if (dl + hdr.dirlistlen < dl)
1852 dl += hdr.dirlistlen;
1853 if (dl > hint_stat.st_size)
1855 p = xmalloc(hdr.dirlistlen + 1);
1856 if (pread(fd, p, hdr.dirlistlen + 1,
1857 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1858 p[hdr.dirlistlen] != '\0') {
1867 * If caller agreed to receive list which includes the default
1868 * paths, we are done. Otherwise, if we still did not
1869 * calculated filtered result, do it now.
1872 return (hints[0] != '\0' ? hints : NULL);
1873 if (filtered_path != NULL)
1877 * Obtain the list of all configured search paths, and the
1878 * list of the default paths.
1880 * First estimate the size of the results.
1882 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1884 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1887 sargs.request = RTLD_DI_SERINFOSIZE;
1888 sargs.serinfo = &smeta;
1889 hargs.request = RTLD_DI_SERINFOSIZE;
1890 hargs.serinfo = &hmeta;
1892 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1894 path_enumerate(hints, fill_search_info, NULL, &hargs);
1896 SLPinfo = xmalloc(smeta.dls_size);
1897 hintinfo = xmalloc(hmeta.dls_size);
1900 * Next fetch both sets of paths.
1902 sargs.request = RTLD_DI_SERINFO;
1903 sargs.serinfo = SLPinfo;
1904 sargs.serpath = &SLPinfo->dls_serpath[0];
1905 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1907 hargs.request = RTLD_DI_SERINFO;
1908 hargs.serinfo = hintinfo;
1909 hargs.serpath = &hintinfo->dls_serpath[0];
1910 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1912 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1914 path_enumerate(hints, fill_search_info, NULL, &hargs);
1917 * Now calculate the difference between two sets, by excluding
1918 * standard paths from the full set.
1922 filtered_path = xmalloc(hdr.dirlistlen + 1);
1923 hintpath = &hintinfo->dls_serpath[0];
1924 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1926 SLPpath = &SLPinfo->dls_serpath[0];
1928 * Check each standard path against current.
1930 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1931 /* matched, skip the path */
1932 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1940 * Not matched against any standard path, add the path
1941 * to result. Separate consequtive paths with ':'.
1944 filtered_path[fndx] = ':';
1948 flen = strlen(hintpath->dls_name);
1949 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1952 filtered_path[fndx] = '\0';
1958 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1962 init_dag(Obj_Entry *root)
1964 const Needed_Entry *needed;
1965 const Objlist_Entry *elm;
1968 if (root->dag_inited)
1970 donelist_init(&donelist);
1972 /* Root object belongs to own DAG. */
1973 objlist_push_tail(&root->dldags, root);
1974 objlist_push_tail(&root->dagmembers, root);
1975 donelist_check(&donelist, root);
1978 * Add dependencies of root object to DAG in breadth order
1979 * by exploiting the fact that each new object get added
1980 * to the tail of the dagmembers list.
1982 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1983 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1984 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1986 objlist_push_tail(&needed->obj->dldags, root);
1987 objlist_push_tail(&root->dagmembers, needed->obj);
1990 root->dag_inited = true;
1994 init_marker(Obj_Entry *marker)
1997 bzero(marker, sizeof(*marker));
1998 marker->marker = true;
2002 globallist_curr(const Obj_Entry *obj)
2009 return (__DECONST(Obj_Entry *, obj));
2010 obj = TAILQ_PREV(obj, obj_entry_q, next);
2015 globallist_next(const Obj_Entry *obj)
2019 obj = TAILQ_NEXT(obj, next);
2023 return (__DECONST(Obj_Entry *, obj));
2027 /* Prevent the object from being unmapped while the bind lock is dropped. */
2029 hold_object(Obj_Entry *obj)
2036 unhold_object(Obj_Entry *obj)
2039 assert(obj->holdcount > 0);
2040 if (--obj->holdcount == 0 && obj->unholdfree)
2041 release_object(obj);
2045 process_z(Obj_Entry *root)
2047 const Objlist_Entry *elm;
2051 * Walk over object DAG and process every dependent object
2052 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2053 * to grow their own DAG.
2055 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2056 * symlook_global() to work.
2058 * For DF_1_NODELETE, the DAG should have its reference upped.
2060 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2064 if (obj->z_nodelete && !obj->ref_nodel) {
2065 dbg("obj %s -z nodelete", obj->path);
2068 obj->ref_nodel = true;
2070 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2071 dbg("obj %s -z global", obj->path);
2072 objlist_push_tail(&list_global, obj);
2078 * Initialize the dynamic linker. The argument is the address at which
2079 * the dynamic linker has been mapped into memory. The primary task of
2080 * this function is to relocate the dynamic linker.
2083 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2085 Obj_Entry objtmp; /* Temporary rtld object */
2086 const Elf_Ehdr *ehdr;
2087 const Elf_Dyn *dyn_rpath;
2088 const Elf_Dyn *dyn_soname;
2089 const Elf_Dyn *dyn_runpath;
2091 #ifdef RTLD_INIT_PAGESIZES_EARLY
2092 /* The page size is required by the dynamic memory allocator. */
2093 init_pagesizes(aux_info);
2097 * Conjure up an Obj_Entry structure for the dynamic linker.
2099 * The "path" member can't be initialized yet because string constants
2100 * cannot yet be accessed. Below we will set it correctly.
2102 memset(&objtmp, 0, sizeof(objtmp));
2105 objtmp.mapbase = mapbase;
2107 objtmp.relocbase = mapbase;
2110 objtmp.dynamic = rtld_dynamic(&objtmp);
2111 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2112 assert(objtmp.needed == NULL);
2113 #if !defined(__mips__)
2114 /* MIPS has a bogus DT_TEXTREL. */
2115 assert(!objtmp.textrel);
2118 * Temporarily put the dynamic linker entry into the object list, so
2119 * that symbols can be found.
2121 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2123 ehdr = (Elf_Ehdr *)mapbase;
2124 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2125 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2127 /* Initialize the object list. */
2128 TAILQ_INIT(&obj_list);
2130 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2131 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2133 #ifndef RTLD_INIT_PAGESIZES_EARLY
2134 /* The page size is required by the dynamic memory allocator. */
2135 init_pagesizes(aux_info);
2138 if (aux_info[AT_OSRELDATE] != NULL)
2139 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2141 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2143 /* Replace the path with a dynamically allocated copy. */
2144 obj_rtld.path = xstrdup(ld_path_rtld);
2146 r_debug.r_brk = r_debug_state;
2147 r_debug.r_state = RT_CONSISTENT;
2151 * Retrieve the array of supported page sizes. The kernel provides the page
2152 * sizes in increasing order.
2155 init_pagesizes(Elf_Auxinfo **aux_info)
2157 static size_t psa[MAXPAGESIZES];
2161 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2163 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2164 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2167 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2170 /* As a fallback, retrieve the base page size. */
2171 size = sizeof(psa[0]);
2172 if (aux_info[AT_PAGESZ] != NULL) {
2173 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2177 mib[1] = HW_PAGESIZE;
2181 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2182 _rtld_error("sysctl for hw.pagesize(s) failed");
2188 npagesizes = size / sizeof(pagesizes[0]);
2189 /* Discard any invalid entries at the end of the array. */
2190 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2195 * Add the init functions from a needed object list (and its recursive
2196 * needed objects) to "list". This is not used directly; it is a helper
2197 * function for initlist_add_objects(). The write lock must be held
2198 * when this function is called.
2201 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2203 /* Recursively process the successor needed objects. */
2204 if (needed->next != NULL)
2205 initlist_add_neededs(needed->next, list);
2207 /* Process the current needed object. */
2208 if (needed->obj != NULL)
2209 initlist_add_objects(needed->obj, needed->obj, list);
2213 * Scan all of the DAGs rooted in the range of objects from "obj" to
2214 * "tail" and add their init functions to "list". This recurses over
2215 * the DAGs and ensure the proper init ordering such that each object's
2216 * needed libraries are initialized before the object itself. At the
2217 * same time, this function adds the objects to the global finalization
2218 * list "list_fini" in the opposite order. The write lock must be
2219 * held when this function is called.
2222 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2226 if (obj->init_scanned || obj->init_done)
2228 obj->init_scanned = true;
2230 /* Recursively process the successor objects. */
2231 nobj = globallist_next(obj);
2232 if (nobj != NULL && obj != tail)
2233 initlist_add_objects(nobj, tail, list);
2235 /* Recursively process the needed objects. */
2236 if (obj->needed != NULL)
2237 initlist_add_neededs(obj->needed, list);
2238 if (obj->needed_filtees != NULL)
2239 initlist_add_neededs(obj->needed_filtees, list);
2240 if (obj->needed_aux_filtees != NULL)
2241 initlist_add_neededs(obj->needed_aux_filtees, list);
2243 /* Add the object to the init list. */
2244 objlist_push_tail(list, obj);
2246 /* Add the object to the global fini list in the reverse order. */
2247 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2248 && !obj->on_fini_list) {
2249 objlist_push_head(&list_fini, obj);
2250 obj->on_fini_list = true;
2255 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2259 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2261 Needed_Entry *needed, *needed1;
2263 for (needed = n; needed != NULL; needed = needed->next) {
2264 if (needed->obj != NULL) {
2265 dlclose_locked(needed->obj, lockstate);
2269 for (needed = n; needed != NULL; needed = needed1) {
2270 needed1 = needed->next;
2276 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2279 free_needed_filtees(obj->needed_filtees, lockstate);
2280 obj->needed_filtees = NULL;
2281 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2282 obj->needed_aux_filtees = NULL;
2283 obj->filtees_loaded = false;
2287 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2288 RtldLockState *lockstate)
2291 for (; needed != NULL; needed = needed->next) {
2292 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2293 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2294 RTLD_LOCAL, lockstate);
2299 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2302 lock_restart_for_upgrade(lockstate);
2303 if (!obj->filtees_loaded) {
2304 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2305 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2306 obj->filtees_loaded = true;
2311 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2315 for (; needed != NULL; needed = needed->next) {
2316 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2317 flags & ~RTLD_LO_NOLOAD);
2318 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2325 * Given a shared object, traverse its list of needed objects, and load
2326 * each of them. Returns 0 on success. Generates an error message and
2327 * returns -1 on failure.
2330 load_needed_objects(Obj_Entry *first, int flags)
2334 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2337 if (process_needed(obj, obj->needed, flags) == -1)
2344 load_preload_objects(void)
2346 char *p = ld_preload;
2348 static const char delim[] = " \t:;";
2353 p += strspn(p, delim);
2354 while (*p != '\0') {
2355 size_t len = strcspn(p, delim);
2360 obj = load_object(p, -1, NULL, 0);
2362 return -1; /* XXX - cleanup */
2363 obj->z_interpose = true;
2366 p += strspn(p, delim);
2368 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2373 printable_path(const char *path)
2376 return (path == NULL ? "<unknown>" : path);
2380 * Load a shared object into memory, if it is not already loaded. The
2381 * object may be specified by name or by user-supplied file descriptor
2382 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2385 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2389 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2398 TAILQ_FOREACH(obj, &obj_list, next) {
2399 if (obj->marker || obj->doomed)
2401 if (object_match_name(obj, name))
2405 path = find_library(name, refobj, &fd);
2413 * search_library_pathfds() opens a fresh file descriptor for the
2414 * library, so there is no need to dup().
2416 } else if (fd_u == -1) {
2418 * If we didn't find a match by pathname, or the name is not
2419 * supplied, open the file and check again by device and inode.
2420 * This avoids false mismatches caused by multiple links or ".."
2423 * To avoid a race, we open the file and use fstat() rather than
2426 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2427 _rtld_error("Cannot open \"%s\"", path);
2432 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2434 _rtld_error("Cannot dup fd");
2439 if (fstat(fd, &sb) == -1) {
2440 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2445 TAILQ_FOREACH(obj, &obj_list, next) {
2446 if (obj->marker || obj->doomed)
2448 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2451 if (obj != NULL && name != NULL) {
2452 object_add_name(obj, name);
2457 if (flags & RTLD_LO_NOLOAD) {
2463 /* First use of this object, so we must map it in */
2464 obj = do_load_object(fd, name, path, &sb, flags);
2473 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2480 * but first, make sure that environment variables haven't been
2481 * used to circumvent the noexec flag on a filesystem.
2483 if (dangerous_ld_env) {
2484 if (fstatfs(fd, &fs) != 0) {
2485 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2488 if (fs.f_flags & MNT_NOEXEC) {
2489 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2493 dbg("loading \"%s\"", printable_path(path));
2494 obj = map_object(fd, printable_path(path), sbp);
2499 * If DT_SONAME is present in the object, digest_dynamic2 already
2500 * added it to the object names.
2503 object_add_name(obj, name);
2505 digest_dynamic(obj, 0);
2506 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2507 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2508 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2510 dbg("refusing to load non-loadable \"%s\"", obj->path);
2511 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2512 munmap(obj->mapbase, obj->mapsize);
2517 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2518 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2521 linkmap_add(obj); /* for GDB & dlinfo() */
2522 max_stack_flags |= obj->stack_flags;
2524 dbg(" %p .. %p: %s", obj->mapbase,
2525 obj->mapbase + obj->mapsize - 1, obj->path);
2527 dbg(" WARNING: %s has impure text", obj->path);
2528 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2535 obj_from_addr(const void *addr)
2539 TAILQ_FOREACH(obj, &obj_list, next) {
2542 if (addr < (void *) obj->mapbase)
2544 if (addr < (void *)(obj->mapbase + obj->mapsize))
2553 Elf_Addr *preinit_addr;
2556 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2557 if (preinit_addr == NULL)
2560 for (index = 0; index < obj_main->preinit_array_num; index++) {
2561 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2562 dbg("calling preinit function for %s at %p", obj_main->path,
2563 (void *)preinit_addr[index]);
2564 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2565 0, 0, obj_main->path);
2566 call_init_pointer(obj_main, preinit_addr[index]);
2572 * Call the finalization functions for each of the objects in "list"
2573 * belonging to the DAG of "root" and referenced once. If NULL "root"
2574 * is specified, every finalization function will be called regardless
2575 * of the reference count and the list elements won't be freed. All of
2576 * the objects are expected to have non-NULL fini functions.
2579 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2583 Elf_Addr *fini_addr;
2586 assert(root == NULL || root->refcount == 1);
2589 root->doomed = true;
2592 * Preserve the current error message since a fini function might
2593 * call into the dynamic linker and overwrite it.
2595 saved_msg = errmsg_save();
2597 STAILQ_FOREACH(elm, list, link) {
2598 if (root != NULL && (elm->obj->refcount != 1 ||
2599 objlist_find(&root->dagmembers, elm->obj) == NULL))
2601 /* Remove object from fini list to prevent recursive invocation. */
2602 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2603 /* Ensure that new references cannot be acquired. */
2604 elm->obj->doomed = true;
2606 hold_object(elm->obj);
2607 lock_release(rtld_bind_lock, lockstate);
2609 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2610 * When this happens, DT_FINI_ARRAY is processed first.
2612 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2613 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2614 for (index = elm->obj->fini_array_num - 1; index >= 0;
2616 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2617 dbg("calling fini function for %s at %p",
2618 elm->obj->path, (void *)fini_addr[index]);
2619 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2620 (void *)fini_addr[index], 0, 0, elm->obj->path);
2621 call_initfini_pointer(elm->obj, fini_addr[index]);
2625 if (elm->obj->fini != (Elf_Addr)NULL) {
2626 dbg("calling fini function for %s at %p", elm->obj->path,
2627 (void *)elm->obj->fini);
2628 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2629 0, 0, elm->obj->path);
2630 call_initfini_pointer(elm->obj, elm->obj->fini);
2632 wlock_acquire(rtld_bind_lock, lockstate);
2633 unhold_object(elm->obj);
2634 /* No need to free anything if process is going down. */
2638 * We must restart the list traversal after every fini call
2639 * because a dlclose() call from the fini function or from
2640 * another thread might have modified the reference counts.
2644 } while (elm != NULL);
2645 errmsg_restore(saved_msg);
2649 * Call the initialization functions for each of the objects in
2650 * "list". All of the objects are expected to have non-NULL init
2654 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2659 Elf_Addr *init_addr;
2663 * Clean init_scanned flag so that objects can be rechecked and
2664 * possibly initialized earlier if any of vectors called below
2665 * cause the change by using dlopen.
2667 TAILQ_FOREACH(obj, &obj_list, next) {
2670 obj->init_scanned = false;
2674 * Preserve the current error message since an init function might
2675 * call into the dynamic linker and overwrite it.
2677 saved_msg = errmsg_save();
2678 STAILQ_FOREACH(elm, list, link) {
2679 if (elm->obj->init_done) /* Initialized early. */
2682 * Race: other thread might try to use this object before current
2683 * one completes the initialization. Not much can be done here
2684 * without better locking.
2686 elm->obj->init_done = true;
2687 hold_object(elm->obj);
2688 lock_release(rtld_bind_lock, lockstate);
2691 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2692 * When this happens, DT_INIT is processed first.
2694 if (elm->obj->init != (Elf_Addr)NULL) {
2695 dbg("calling init function for %s at %p", elm->obj->path,
2696 (void *)elm->obj->init);
2697 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2698 0, 0, elm->obj->path);
2699 call_initfini_pointer(elm->obj, elm->obj->init);
2701 init_addr = (Elf_Addr *)elm->obj->init_array;
2702 if (init_addr != NULL) {
2703 for (index = 0; index < elm->obj->init_array_num; index++) {
2704 if (init_addr[index] != 0 && init_addr[index] != 1) {
2705 dbg("calling init function for %s at %p", elm->obj->path,
2706 (void *)init_addr[index]);
2707 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2708 (void *)init_addr[index], 0, 0, elm->obj->path);
2709 call_init_pointer(elm->obj, init_addr[index]);
2713 wlock_acquire(rtld_bind_lock, lockstate);
2714 unhold_object(elm->obj);
2716 errmsg_restore(saved_msg);
2720 objlist_clear(Objlist *list)
2724 while (!STAILQ_EMPTY(list)) {
2725 elm = STAILQ_FIRST(list);
2726 STAILQ_REMOVE_HEAD(list, link);
2731 static Objlist_Entry *
2732 objlist_find(Objlist *list, const Obj_Entry *obj)
2736 STAILQ_FOREACH(elm, list, link)
2737 if (elm->obj == obj)
2743 objlist_init(Objlist *list)
2749 objlist_push_head(Objlist *list, Obj_Entry *obj)
2753 elm = NEW(Objlist_Entry);
2755 STAILQ_INSERT_HEAD(list, elm, link);
2759 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2763 elm = NEW(Objlist_Entry);
2765 STAILQ_INSERT_TAIL(list, elm, link);
2769 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2771 Objlist_Entry *elm, *listelm;
2773 STAILQ_FOREACH(listelm, list, link) {
2774 if (listelm->obj == listobj)
2777 elm = NEW(Objlist_Entry);
2779 if (listelm != NULL)
2780 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2782 STAILQ_INSERT_TAIL(list, elm, link);
2786 objlist_remove(Objlist *list, Obj_Entry *obj)
2790 if ((elm = objlist_find(list, obj)) != NULL) {
2791 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2797 * Relocate dag rooted in the specified object.
2798 * Returns 0 on success, or -1 on failure.
2802 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2803 int flags, RtldLockState *lockstate)
2809 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2810 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2819 * Prepare for, or clean after, relocating an object marked with
2820 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2821 * segments are remapped read-write. After relocations are done, the
2822 * segment's permissions are returned back to the modes specified in
2823 * the phdrs. If any relocation happened, or always for wired
2824 * program, COW is triggered.
2827 reloc_textrel_prot(Obj_Entry *obj, bool before)
2834 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2836 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2838 base = obj->relocbase + trunc_page(ph->p_vaddr);
2839 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2840 trunc_page(ph->p_vaddr);
2841 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2842 if (mprotect(base, sz, prot) == -1) {
2843 _rtld_error("%s: Cannot write-%sable text segment: %s",
2844 obj->path, before ? "en" : "dis",
2845 rtld_strerror(errno));
2853 * Relocate single object.
2854 * Returns 0 on success, or -1 on failure.
2857 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2858 int flags, RtldLockState *lockstate)
2863 obj->relocated = true;
2865 dbg("relocating \"%s\"", obj->path);
2867 if (obj->symtab == NULL || obj->strtab == NULL ||
2868 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2869 _rtld_error("%s: Shared object has no run-time symbol table",
2874 /* There are relocations to the write-protected text segment. */
2875 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2878 /* Process the non-PLT non-IFUNC relocations. */
2879 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2882 /* Re-protected the text segment. */
2883 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2886 /* Set the special PLT or GOT entries. */
2889 /* Process the PLT relocations. */
2890 if (reloc_plt(obj, flags, lockstate) == -1)
2892 /* Relocate the jump slots if we are doing immediate binding. */
2893 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
2897 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2901 * Set up the magic number and version in the Obj_Entry. These
2902 * were checked in the crt1.o from the original ElfKit, so we
2903 * set them for backward compatibility.
2905 obj->magic = RTLD_MAGIC;
2906 obj->version = RTLD_VERSION;
2912 * Relocate newly-loaded shared objects. The argument is a pointer to
2913 * the Obj_Entry for the first such object. All objects from the first
2914 * to the end of the list of objects are relocated. Returns 0 on success,
2918 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2919 int flags, RtldLockState *lockstate)
2924 for (error = 0, obj = first; obj != NULL;
2925 obj = TAILQ_NEXT(obj, next)) {
2928 error = relocate_object(obj, bind_now, rtldobj, flags,
2937 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2938 * referencing STT_GNU_IFUNC symbols is postponed till the other
2939 * relocations are done. The indirect functions specified as
2940 * ifunc are allowed to call other symbols, so we need to have
2941 * objects relocated before asking for resolution from indirects.
2943 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2944 * instead of the usual lazy handling of PLT slots. It is
2945 * consistent with how GNU does it.
2948 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2949 RtldLockState *lockstate)
2952 if (obj->ifuncs_resolved)
2954 obj->ifuncs_resolved = true;
2955 if (!obj->irelative && !((obj->bind_now || bind_now) && obj->gnu_ifunc))
2957 if (obj_disable_relro(obj) == -1 ||
2958 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
2959 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2960 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
2961 obj_enforce_relro(obj) == -1)
2967 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2968 RtldLockState *lockstate)
2973 STAILQ_FOREACH(elm, list, link) {
2977 if (resolve_object_ifunc(obj, bind_now, flags,
2985 * Cleanup procedure. It will be called (by the atexit mechanism) just
2986 * before the process exits.
2991 RtldLockState lockstate;
2993 wlock_acquire(rtld_bind_lock, &lockstate);
2995 objlist_call_fini(&list_fini, NULL, &lockstate);
2996 /* No need to remove the items from the list, since we are exiting. */
2997 if (!libmap_disable)
2999 lock_release(rtld_bind_lock, &lockstate);
3003 * Iterate over a search path, translate each element, and invoke the
3004 * callback on the result.
3007 path_enumerate(const char *path, path_enum_proc callback,
3008 const char *refobj_path, void *arg)
3014 path += strspn(path, ":;");
3015 while (*path != '\0') {
3019 len = strcspn(path, ":;");
3020 trans = lm_findn(refobj_path, path, len);
3022 res = callback(trans, strlen(trans), arg);
3024 res = callback(path, len, arg);
3030 path += strspn(path, ":;");
3036 struct try_library_args {
3045 try_library_path(const char *dir, size_t dirlen, void *param)
3047 struct try_library_args *arg;
3051 if (*dir == '/' || trust) {
3054 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3057 pathname = arg->buffer;
3058 strncpy(pathname, dir, dirlen);
3059 pathname[dirlen] = '/';
3060 strcpy(pathname + dirlen + 1, arg->name);
3062 dbg(" Trying \"%s\"", pathname);
3063 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3065 dbg(" Opened \"%s\", fd %d", pathname, fd);
3066 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3067 strcpy(pathname, arg->buffer);
3071 dbg(" Failed to open \"%s\": %s",
3072 pathname, rtld_strerror(errno));
3079 search_library_path(const char *name, const char *path,
3080 const char *refobj_path, int *fdp)
3083 struct try_library_args arg;
3089 arg.namelen = strlen(name);
3090 arg.buffer = xmalloc(PATH_MAX);
3091 arg.buflen = PATH_MAX;
3094 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3104 * Finds the library with the given name using the directory descriptors
3105 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3107 * Returns a freshly-opened close-on-exec file descriptor for the library,
3108 * or -1 if the library cannot be found.
3111 search_library_pathfds(const char *name, const char *path, int *fdp)
3113 char *envcopy, *fdstr, *found, *last_token;
3117 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3119 /* Don't load from user-specified libdirs into setuid binaries. */
3123 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3127 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3128 if (name[0] == '/') {
3129 dbg("Absolute path (%s) passed to %s", name, __func__);
3134 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3135 * copy of the path, as strtok_r rewrites separator tokens
3139 envcopy = xstrdup(path);
3140 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3141 fdstr = strtok_r(NULL, ":", &last_token)) {
3142 dirfd = parse_integer(fdstr);
3144 _rtld_error("failed to parse directory FD: '%s'",
3148 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3151 len = strlen(fdstr) + strlen(name) + 3;
3152 found = xmalloc(len);
3153 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3154 _rtld_error("error generating '%d/%s'",
3158 dbg("open('%s') => %d", found, fd);
3169 dlclose(void *handle)
3171 RtldLockState lockstate;
3174 wlock_acquire(rtld_bind_lock, &lockstate);
3175 error = dlclose_locked(handle, &lockstate);
3176 lock_release(rtld_bind_lock, &lockstate);
3181 dlclose_locked(void *handle, RtldLockState *lockstate)
3185 root = dlcheck(handle);
3188 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3191 /* Unreference the object and its dependencies. */
3192 root->dl_refcount--;
3194 if (root->refcount == 1) {
3196 * The object will be no longer referenced, so we must unload it.
3197 * First, call the fini functions.
3199 objlist_call_fini(&list_fini, root, lockstate);
3203 /* Finish cleaning up the newly-unreferenced objects. */
3204 GDB_STATE(RT_DELETE,&root->linkmap);
3205 unload_object(root, lockstate);
3206 GDB_STATE(RT_CONSISTENT,NULL);
3210 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3217 char *msg = error_message;
3218 error_message = NULL;
3223 * This function is deprecated and has no effect.
3226 dllockinit(void *context,
3227 void *(*_lock_create)(void *context) __unused,
3228 void (*_rlock_acquire)(void *lock) __unused,
3229 void (*_wlock_acquire)(void *lock) __unused,
3230 void (*_lock_release)(void *lock) __unused,
3231 void (*_lock_destroy)(void *lock) __unused,
3232 void (*context_destroy)(void *context))
3234 static void *cur_context;
3235 static void (*cur_context_destroy)(void *);
3237 /* Just destroy the context from the previous call, if necessary. */
3238 if (cur_context_destroy != NULL)
3239 cur_context_destroy(cur_context);
3240 cur_context = context;
3241 cur_context_destroy = context_destroy;
3245 dlopen(const char *name, int mode)
3248 return (rtld_dlopen(name, -1, mode));
3252 fdlopen(int fd, int mode)
3255 return (rtld_dlopen(NULL, fd, mode));
3259 rtld_dlopen(const char *name, int fd, int mode)
3261 RtldLockState lockstate;
3264 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3265 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3266 if (ld_tracing != NULL) {
3267 rlock_acquire(rtld_bind_lock, &lockstate);
3268 if (sigsetjmp(lockstate.env, 0) != 0)
3269 lock_upgrade(rtld_bind_lock, &lockstate);
3270 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3271 lock_release(rtld_bind_lock, &lockstate);
3273 lo_flags = RTLD_LO_DLOPEN;
3274 if (mode & RTLD_NODELETE)
3275 lo_flags |= RTLD_LO_NODELETE;
3276 if (mode & RTLD_NOLOAD)
3277 lo_flags |= RTLD_LO_NOLOAD;
3278 if (ld_tracing != NULL)
3279 lo_flags |= RTLD_LO_TRACE;
3281 return (dlopen_object(name, fd, obj_main, lo_flags,
3282 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3286 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3291 if (obj->refcount == 0)
3292 unload_object(obj, lockstate);
3296 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3297 int mode, RtldLockState *lockstate)
3299 Obj_Entry *old_obj_tail;
3302 RtldLockState mlockstate;
3305 objlist_init(&initlist);
3307 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3308 wlock_acquire(rtld_bind_lock, &mlockstate);
3309 lockstate = &mlockstate;
3311 GDB_STATE(RT_ADD,NULL);
3313 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3315 if (name == NULL && fd == -1) {
3319 obj = load_object(name, fd, refobj, lo_flags);
3324 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3325 objlist_push_tail(&list_global, obj);
3326 if (globallist_next(old_obj_tail) != NULL) {
3327 /* We loaded something new. */
3328 assert(globallist_next(old_obj_tail) == obj);
3330 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls &&
3331 !allocate_tls_offset(obj)) {
3332 _rtld_error("%s: No space available "
3333 "for static Thread Local Storage", obj->path);
3337 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3342 result = rtld_verify_versions(&obj->dagmembers);
3343 if (result != -1 && ld_tracing)
3345 if (result == -1 || relocate_object_dag(obj,
3346 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3347 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3349 dlopen_cleanup(obj, lockstate);
3351 } else if (lo_flags & RTLD_LO_EARLY) {
3353 * Do not call the init functions for early loaded
3354 * filtees. The image is still not initialized enough
3357 * Our object is found by the global object list and
3358 * will be ordered among all init calls done right
3359 * before transferring control to main.
3362 /* Make list of init functions to call. */
3363 initlist_add_objects(obj, obj, &initlist);
3366 * Process all no_delete or global objects here, given
3367 * them own DAGs to prevent their dependencies from being
3368 * unloaded. This has to be done after we have loaded all
3369 * of the dependencies, so that we do not miss any.
3375 * Bump the reference counts for objects on this DAG. If
3376 * this is the first dlopen() call for the object that was
3377 * already loaded as a dependency, initialize the dag
3383 if ((lo_flags & RTLD_LO_TRACE) != 0)
3386 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3387 obj->z_nodelete) && !obj->ref_nodel) {
3388 dbg("obj %s nodelete", obj->path);
3390 obj->z_nodelete = obj->ref_nodel = true;
3394 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3396 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3398 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3399 map_stacks_exec(lockstate);
3401 distribute_static_tls(&initlist, lockstate);
3404 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3405 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3407 objlist_clear(&initlist);
3408 dlopen_cleanup(obj, lockstate);
3409 if (lockstate == &mlockstate)
3410 lock_release(rtld_bind_lock, lockstate);
3414 if (!(lo_flags & RTLD_LO_EARLY)) {
3415 /* Call the init functions. */
3416 objlist_call_init(&initlist, lockstate);
3418 objlist_clear(&initlist);
3419 if (lockstate == &mlockstate)
3420 lock_release(rtld_bind_lock, lockstate);
3423 trace_loaded_objects(obj);
3424 if (lockstate == &mlockstate)
3425 lock_release(rtld_bind_lock, lockstate);
3430 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3434 const Obj_Entry *obj, *defobj;
3437 RtldLockState lockstate;
3444 symlook_init(&req, name);
3446 req.flags = flags | SYMLOOK_IN_PLT;
3447 req.lockstate = &lockstate;
3449 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3450 rlock_acquire(rtld_bind_lock, &lockstate);
3451 if (sigsetjmp(lockstate.env, 0) != 0)
3452 lock_upgrade(rtld_bind_lock, &lockstate);
3453 if (handle == NULL || handle == RTLD_NEXT ||
3454 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3456 if ((obj = obj_from_addr(retaddr)) == NULL) {
3457 _rtld_error("Cannot determine caller's shared object");
3458 lock_release(rtld_bind_lock, &lockstate);
3459 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3462 if (handle == NULL) { /* Just the caller's shared object. */
3463 res = symlook_obj(&req, obj);
3466 defobj = req.defobj_out;
3468 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3469 handle == RTLD_SELF) { /* ... caller included */
3470 if (handle == RTLD_NEXT)
3471 obj = globallist_next(obj);
3472 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3475 res = symlook_obj(&req, obj);
3478 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3480 defobj = req.defobj_out;
3481 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3487 * Search the dynamic linker itself, and possibly resolve the
3488 * symbol from there. This is how the application links to
3489 * dynamic linker services such as dlopen.
3491 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3492 res = symlook_obj(&req, &obj_rtld);
3495 defobj = req.defobj_out;
3499 assert(handle == RTLD_DEFAULT);
3500 res = symlook_default(&req, obj);
3502 defobj = req.defobj_out;
3507 if ((obj = dlcheck(handle)) == NULL) {
3508 lock_release(rtld_bind_lock, &lockstate);
3509 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3513 donelist_init(&donelist);
3514 if (obj->mainprog) {
3515 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3516 res = symlook_global(&req, &donelist);
3519 defobj = req.defobj_out;
3522 * Search the dynamic linker itself, and possibly resolve the
3523 * symbol from there. This is how the application links to
3524 * dynamic linker services such as dlopen.
3526 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3527 res = symlook_obj(&req, &obj_rtld);
3530 defobj = req.defobj_out;
3535 /* Search the whole DAG rooted at the given object. */
3536 res = symlook_list(&req, &obj->dagmembers, &donelist);
3539 defobj = req.defobj_out;
3545 lock_release(rtld_bind_lock, &lockstate);
3548 * The value required by the caller is derived from the value
3549 * of the symbol. this is simply the relocated value of the
3552 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3553 sym = make_function_pointer(def, defobj);
3554 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3555 sym = rtld_resolve_ifunc(defobj, def);
3556 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3557 ti.ti_module = defobj->tlsindex;
3558 ti.ti_offset = def->st_value;
3559 sym = __tls_get_addr(&ti);
3561 sym = defobj->relocbase + def->st_value;
3562 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3566 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3567 ve != NULL ? ve->name : "");
3568 lock_release(rtld_bind_lock, &lockstate);
3569 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3574 dlsym(void *handle, const char *name)
3576 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3581 dlfunc(void *handle, const char *name)
3588 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3594 dlvsym(void *handle, const char *name, const char *version)
3598 ventry.name = version;
3600 ventry.hash = elf_hash(version);
3602 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3607 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3609 const Obj_Entry *obj;
3610 RtldLockState lockstate;
3612 rlock_acquire(rtld_bind_lock, &lockstate);
3613 obj = obj_from_addr(addr);
3615 _rtld_error("No shared object contains address");
3616 lock_release(rtld_bind_lock, &lockstate);
3619 rtld_fill_dl_phdr_info(obj, phdr_info);
3620 lock_release(rtld_bind_lock, &lockstate);
3625 dladdr(const void *addr, Dl_info *info)
3627 const Obj_Entry *obj;
3630 unsigned long symoffset;
3631 RtldLockState lockstate;
3633 rlock_acquire(rtld_bind_lock, &lockstate);
3634 obj = obj_from_addr(addr);
3636 _rtld_error("No shared object contains address");
3637 lock_release(rtld_bind_lock, &lockstate);
3640 info->dli_fname = obj->path;
3641 info->dli_fbase = obj->mapbase;
3642 info->dli_saddr = (void *)0;
3643 info->dli_sname = NULL;
3646 * Walk the symbol list looking for the symbol whose address is
3647 * closest to the address sent in.
3649 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3650 def = obj->symtab + symoffset;
3653 * For skip the symbol if st_shndx is either SHN_UNDEF or
3656 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3660 * If the symbol is greater than the specified address, or if it
3661 * is further away from addr than the current nearest symbol,
3664 symbol_addr = obj->relocbase + def->st_value;
3665 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3668 /* Update our idea of the nearest symbol. */
3669 info->dli_sname = obj->strtab + def->st_name;
3670 info->dli_saddr = symbol_addr;
3673 if (info->dli_saddr == addr)
3676 lock_release(rtld_bind_lock, &lockstate);
3681 dlinfo(void *handle, int request, void *p)
3683 const Obj_Entry *obj;
3684 RtldLockState lockstate;
3687 rlock_acquire(rtld_bind_lock, &lockstate);
3689 if (handle == NULL || handle == RTLD_SELF) {
3692 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3693 if ((obj = obj_from_addr(retaddr)) == NULL)
3694 _rtld_error("Cannot determine caller's shared object");
3696 obj = dlcheck(handle);
3699 lock_release(rtld_bind_lock, &lockstate);
3705 case RTLD_DI_LINKMAP:
3706 *((struct link_map const **)p) = &obj->linkmap;
3708 case RTLD_DI_ORIGIN:
3709 error = rtld_dirname(obj->path, p);
3712 case RTLD_DI_SERINFOSIZE:
3713 case RTLD_DI_SERINFO:
3714 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3718 _rtld_error("Invalid request %d passed to dlinfo()", request);
3722 lock_release(rtld_bind_lock, &lockstate);
3728 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3731 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3732 phdr_info->dlpi_name = obj->path;
3733 phdr_info->dlpi_phdr = obj->phdr;
3734 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3735 phdr_info->dlpi_tls_modid = obj->tlsindex;
3736 phdr_info->dlpi_tls_data = obj->tlsinit;
3737 phdr_info->dlpi_adds = obj_loads;
3738 phdr_info->dlpi_subs = obj_loads - obj_count;
3742 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3744 struct dl_phdr_info phdr_info;
3745 Obj_Entry *obj, marker;
3746 RtldLockState bind_lockstate, phdr_lockstate;
3749 init_marker(&marker);
3752 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3753 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3754 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3755 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3756 rtld_fill_dl_phdr_info(obj, &phdr_info);
3758 lock_release(rtld_bind_lock, &bind_lockstate);
3760 error = callback(&phdr_info, sizeof phdr_info, param);
3762 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3764 obj = globallist_next(&marker);
3765 TAILQ_REMOVE(&obj_list, &marker, next);
3767 lock_release(rtld_bind_lock, &bind_lockstate);
3768 lock_release(rtld_phdr_lock, &phdr_lockstate);
3774 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3775 lock_release(rtld_bind_lock, &bind_lockstate);
3776 error = callback(&phdr_info, sizeof(phdr_info), param);
3778 lock_release(rtld_phdr_lock, &phdr_lockstate);
3783 fill_search_info(const char *dir, size_t dirlen, void *param)
3785 struct fill_search_info_args *arg;
3789 if (arg->request == RTLD_DI_SERINFOSIZE) {
3790 arg->serinfo->dls_cnt ++;
3791 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3793 struct dl_serpath *s_entry;
3795 s_entry = arg->serpath;
3796 s_entry->dls_name = arg->strspace;
3797 s_entry->dls_flags = arg->flags;
3799 strncpy(arg->strspace, dir, dirlen);
3800 arg->strspace[dirlen] = '\0';
3802 arg->strspace += dirlen + 1;
3810 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3812 struct dl_serinfo _info;
3813 struct fill_search_info_args args;
3815 args.request = RTLD_DI_SERINFOSIZE;
3816 args.serinfo = &_info;
3818 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3821 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3822 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3823 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3824 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3825 if (!obj->z_nodeflib)
3826 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3829 if (request == RTLD_DI_SERINFOSIZE) {
3830 info->dls_size = _info.dls_size;
3831 info->dls_cnt = _info.dls_cnt;
3835 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3836 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3840 args.request = RTLD_DI_SERINFO;
3841 args.serinfo = info;
3842 args.serpath = &info->dls_serpath[0];
3843 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3845 args.flags = LA_SER_RUNPATH;
3846 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
3849 args.flags = LA_SER_LIBPATH;
3850 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
3853 args.flags = LA_SER_RUNPATH;
3854 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
3857 args.flags = LA_SER_CONFIG;
3858 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
3862 args.flags = LA_SER_DEFAULT;
3863 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
3864 fill_search_info, NULL, &args) != NULL)
3870 rtld_dirname(const char *path, char *bname)
3874 /* Empty or NULL string gets treated as "." */
3875 if (path == NULL || *path == '\0') {
3881 /* Strip trailing slashes */
3882 endp = path + strlen(path) - 1;
3883 while (endp > path && *endp == '/')
3886 /* Find the start of the dir */
3887 while (endp > path && *endp != '/')
3890 /* Either the dir is "/" or there are no slashes */
3892 bname[0] = *endp == '/' ? '/' : '.';
3898 } while (endp > path && *endp == '/');
3901 if (endp - path + 2 > PATH_MAX)
3903 _rtld_error("Filename is too long: %s", path);
3907 strncpy(bname, path, endp - path + 1);
3908 bname[endp - path + 1] = '\0';
3913 rtld_dirname_abs(const char *path, char *base)
3917 if (realpath(path, base) == NULL)
3919 dbg("%s -> %s", path, base);
3920 last = strrchr(base, '/');
3929 linkmap_add(Obj_Entry *obj)
3931 struct link_map *l = &obj->linkmap;
3932 struct link_map *prev;
3934 obj->linkmap.l_name = obj->path;
3935 obj->linkmap.l_addr = obj->mapbase;
3936 obj->linkmap.l_ld = obj->dynamic;
3938 /* GDB needs load offset on MIPS to use the symbols */
3939 obj->linkmap.l_offs = obj->relocbase;
3942 if (r_debug.r_map == NULL) {
3948 * Scan to the end of the list, but not past the entry for the
3949 * dynamic linker, which we want to keep at the very end.
3951 for (prev = r_debug.r_map;
3952 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3953 prev = prev->l_next)
3956 /* Link in the new entry. */
3958 l->l_next = prev->l_next;
3959 if (l->l_next != NULL)
3960 l->l_next->l_prev = l;
3965 linkmap_delete(Obj_Entry *obj)
3967 struct link_map *l = &obj->linkmap;
3969 if (l->l_prev == NULL) {
3970 if ((r_debug.r_map = l->l_next) != NULL)
3971 l->l_next->l_prev = NULL;
3975 if ((l->l_prev->l_next = l->l_next) != NULL)
3976 l->l_next->l_prev = l->l_prev;
3980 * Function for the debugger to set a breakpoint on to gain control.
3982 * The two parameters allow the debugger to easily find and determine
3983 * what the runtime loader is doing and to whom it is doing it.
3985 * When the loadhook trap is hit (r_debug_state, set at program
3986 * initialization), the arguments can be found on the stack:
3988 * +8 struct link_map *m
3989 * +4 struct r_debug *rd
3993 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
3996 * The following is a hack to force the compiler to emit calls to
3997 * this function, even when optimizing. If the function is empty,
3998 * the compiler is not obliged to emit any code for calls to it,
3999 * even when marked __noinline. However, gdb depends on those
4002 __compiler_membar();
4006 * A function called after init routines have completed. This can be used to
4007 * break before a program's entry routine is called, and can be used when
4008 * main is not available in the symbol table.
4011 _r_debug_postinit(struct link_map *m __unused)
4014 /* See r_debug_state(). */
4015 __compiler_membar();
4019 release_object(Obj_Entry *obj)
4022 if (obj->holdcount > 0) {
4023 obj->unholdfree = true;
4026 munmap(obj->mapbase, obj->mapsize);
4027 linkmap_delete(obj);
4032 * Get address of the pointer variable in the main program.
4033 * Prefer non-weak symbol over the weak one.
4035 static const void **
4036 get_program_var_addr(const char *name, RtldLockState *lockstate)
4041 symlook_init(&req, name);
4042 req.lockstate = lockstate;
4043 donelist_init(&donelist);
4044 if (symlook_global(&req, &donelist) != 0)
4046 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4047 return ((const void **)make_function_pointer(req.sym_out,
4049 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4050 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4052 return ((const void **)(req.defobj_out->relocbase +
4053 req.sym_out->st_value));
4057 * Set a pointer variable in the main program to the given value. This
4058 * is used to set key variables such as "environ" before any of the
4059 * init functions are called.
4062 set_program_var(const char *name, const void *value)
4066 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4067 dbg("\"%s\": *%p <-- %p", name, addr, value);
4073 * Search the global objects, including dependencies and main object,
4074 * for the given symbol.
4077 symlook_global(SymLook *req, DoneList *donelist)
4080 const Objlist_Entry *elm;
4083 symlook_init_from_req(&req1, req);
4085 /* Search all objects loaded at program start up. */
4086 if (req->defobj_out == NULL ||
4087 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4088 res = symlook_list(&req1, &list_main, donelist);
4089 if (res == 0 && (req->defobj_out == NULL ||
4090 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4091 req->sym_out = req1.sym_out;
4092 req->defobj_out = req1.defobj_out;
4093 assert(req->defobj_out != NULL);
4097 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4098 STAILQ_FOREACH(elm, &list_global, link) {
4099 if (req->defobj_out != NULL &&
4100 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4102 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4103 if (res == 0 && (req->defobj_out == NULL ||
4104 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4105 req->sym_out = req1.sym_out;
4106 req->defobj_out = req1.defobj_out;
4107 assert(req->defobj_out != NULL);
4111 return (req->sym_out != NULL ? 0 : ESRCH);
4115 * Given a symbol name in a referencing object, find the corresponding
4116 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4117 * no definition was found. Returns a pointer to the Obj_Entry of the
4118 * defining object via the reference parameter DEFOBJ_OUT.
4121 symlook_default(SymLook *req, const Obj_Entry *refobj)
4124 const Objlist_Entry *elm;
4128 donelist_init(&donelist);
4129 symlook_init_from_req(&req1, req);
4132 * Look first in the referencing object if linked symbolically,
4133 * and similarly handle protected symbols.
4135 res = symlook_obj(&req1, refobj);
4136 if (res == 0 && (refobj->symbolic ||
4137 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4138 req->sym_out = req1.sym_out;
4139 req->defobj_out = req1.defobj_out;
4140 assert(req->defobj_out != NULL);
4142 if (refobj->symbolic || req->defobj_out != NULL)
4143 donelist_check(&donelist, refobj);
4145 symlook_global(req, &donelist);
4147 /* Search all dlopened DAGs containing the referencing object. */
4148 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4149 if (req->sym_out != NULL &&
4150 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4152 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4153 if (res == 0 && (req->sym_out == NULL ||
4154 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4155 req->sym_out = req1.sym_out;
4156 req->defobj_out = req1.defobj_out;
4157 assert(req->defobj_out != NULL);
4162 * Search the dynamic linker itself, and possibly resolve the
4163 * symbol from there. This is how the application links to
4164 * dynamic linker services such as dlopen.
4166 if (req->sym_out == NULL ||
4167 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4168 res = symlook_obj(&req1, &obj_rtld);
4170 req->sym_out = req1.sym_out;
4171 req->defobj_out = req1.defobj_out;
4172 assert(req->defobj_out != NULL);
4176 return (req->sym_out != NULL ? 0 : ESRCH);
4180 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4183 const Obj_Entry *defobj;
4184 const Objlist_Entry *elm;
4190 STAILQ_FOREACH(elm, objlist, link) {
4191 if (donelist_check(dlp, elm->obj))
4193 symlook_init_from_req(&req1, req);
4194 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4195 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4197 defobj = req1.defobj_out;
4198 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4205 req->defobj_out = defobj;
4212 * Search the chain of DAGS cointed to by the given Needed_Entry
4213 * for a symbol of the given name. Each DAG is scanned completely
4214 * before advancing to the next one. Returns a pointer to the symbol,
4215 * or NULL if no definition was found.
4218 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4221 const Needed_Entry *n;
4222 const Obj_Entry *defobj;
4228 symlook_init_from_req(&req1, req);
4229 for (n = needed; n != NULL; n = n->next) {
4230 if (n->obj == NULL ||
4231 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4233 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4235 defobj = req1.defobj_out;
4236 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4242 req->defobj_out = defobj;
4249 * Search the symbol table of a single shared object for a symbol of
4250 * the given name and version, if requested. Returns a pointer to the
4251 * symbol, or NULL if no definition was found. If the object is
4252 * filter, return filtered symbol from filtee.
4254 * The symbol's hash value is passed in for efficiency reasons; that
4255 * eliminates many recomputations of the hash value.
4258 symlook_obj(SymLook *req, const Obj_Entry *obj)
4262 int flags, res, mres;
4265 * If there is at least one valid hash at this point, we prefer to
4266 * use the faster GNU version if available.
4268 if (obj->valid_hash_gnu)
4269 mres = symlook_obj1_gnu(req, obj);
4270 else if (obj->valid_hash_sysv)
4271 mres = symlook_obj1_sysv(req, obj);
4276 if (obj->needed_filtees != NULL) {
4277 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4278 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4279 donelist_init(&donelist);
4280 symlook_init_from_req(&req1, req);
4281 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4283 req->sym_out = req1.sym_out;
4284 req->defobj_out = req1.defobj_out;
4288 if (obj->needed_aux_filtees != NULL) {
4289 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4290 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4291 donelist_init(&donelist);
4292 symlook_init_from_req(&req1, req);
4293 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4295 req->sym_out = req1.sym_out;
4296 req->defobj_out = req1.defobj_out;
4304 /* Symbol match routine common to both hash functions */
4306 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4307 const unsigned long symnum)
4310 const Elf_Sym *symp;
4313 symp = obj->symtab + symnum;
4314 strp = obj->strtab + symp->st_name;
4316 switch (ELF_ST_TYPE(symp->st_info)) {
4322 if (symp->st_value == 0)
4326 if (symp->st_shndx != SHN_UNDEF)
4329 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4330 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4337 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4340 if (req->ventry == NULL) {
4341 if (obj->versyms != NULL) {
4342 verndx = VER_NDX(obj->versyms[symnum]);
4343 if (verndx > obj->vernum) {
4345 "%s: symbol %s references wrong version %d",
4346 obj->path, obj->strtab + symnum, verndx);
4350 * If we are not called from dlsym (i.e. this
4351 * is a normal relocation from unversioned
4352 * binary), accept the symbol immediately if
4353 * it happens to have first version after this
4354 * shared object became versioned. Otherwise,
4355 * if symbol is versioned and not hidden,
4356 * remember it. If it is the only symbol with
4357 * this name exported by the shared object, it
4358 * will be returned as a match by the calling
4359 * function. If symbol is global (verndx < 2)
4360 * accept it unconditionally.
4362 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4363 verndx == VER_NDX_GIVEN) {
4364 result->sym_out = symp;
4367 else if (verndx >= VER_NDX_GIVEN) {
4368 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4370 if (result->vsymp == NULL)
4371 result->vsymp = symp;
4377 result->sym_out = symp;
4380 if (obj->versyms == NULL) {
4381 if (object_match_name(obj, req->ventry->name)) {
4382 _rtld_error("%s: object %s should provide version %s "
4383 "for symbol %s", obj_rtld.path, obj->path,
4384 req->ventry->name, obj->strtab + symnum);
4388 verndx = VER_NDX(obj->versyms[symnum]);
4389 if (verndx > obj->vernum) {
4390 _rtld_error("%s: symbol %s references wrong version %d",
4391 obj->path, obj->strtab + symnum, verndx);
4394 if (obj->vertab[verndx].hash != req->ventry->hash ||
4395 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4397 * Version does not match. Look if this is a
4398 * global symbol and if it is not hidden. If
4399 * global symbol (verndx < 2) is available,
4400 * use it. Do not return symbol if we are
4401 * called by dlvsym, because dlvsym looks for
4402 * a specific version and default one is not
4403 * what dlvsym wants.
4405 if ((req->flags & SYMLOOK_DLSYM) ||
4406 (verndx >= VER_NDX_GIVEN) ||
4407 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4411 result->sym_out = symp;
4416 * Search for symbol using SysV hash function.
4417 * obj->buckets is known not to be NULL at this point; the test for this was
4418 * performed with the obj->valid_hash_sysv assignment.
4421 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4423 unsigned long symnum;
4424 Sym_Match_Result matchres;
4426 matchres.sym_out = NULL;
4427 matchres.vsymp = NULL;
4428 matchres.vcount = 0;
4430 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4431 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4432 if (symnum >= obj->nchains)
4433 return (ESRCH); /* Bad object */
4435 if (matched_symbol(req, obj, &matchres, symnum)) {
4436 req->sym_out = matchres.sym_out;
4437 req->defobj_out = obj;
4441 if (matchres.vcount == 1) {
4442 req->sym_out = matchres.vsymp;
4443 req->defobj_out = obj;
4449 /* Search for symbol using GNU hash function */
4451 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4453 Elf_Addr bloom_word;
4454 const Elf32_Word *hashval;
4456 Sym_Match_Result matchres;
4457 unsigned int h1, h2;
4458 unsigned long symnum;
4460 matchres.sym_out = NULL;
4461 matchres.vsymp = NULL;
4462 matchres.vcount = 0;
4464 /* Pick right bitmask word from Bloom filter array */
4465 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4466 obj->maskwords_bm_gnu];
4468 /* Calculate modulus word size of gnu hash and its derivative */
4469 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4470 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4472 /* Filter out the "definitely not in set" queries */
4473 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4476 /* Locate hash chain and corresponding value element*/
4477 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4480 hashval = &obj->chain_zero_gnu[bucket];
4482 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4483 symnum = hashval - obj->chain_zero_gnu;
4484 if (matched_symbol(req, obj, &matchres, symnum)) {
4485 req->sym_out = matchres.sym_out;
4486 req->defobj_out = obj;
4490 } while ((*hashval++ & 1) == 0);
4491 if (matchres.vcount == 1) {
4492 req->sym_out = matchres.vsymp;
4493 req->defobj_out = obj;
4500 trace_loaded_objects(Obj_Entry *obj)
4502 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4505 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4508 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4509 fmt1 = "\t%o => %p (%x)\n";
4511 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4512 fmt2 = "\t%o (%x)\n";
4514 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4516 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4517 Needed_Entry *needed;
4518 const char *name, *path;
4523 if (list_containers && obj->needed != NULL)
4524 rtld_printf("%s:\n", obj->path);
4525 for (needed = obj->needed; needed; needed = needed->next) {
4526 if (needed->obj != NULL) {
4527 if (needed->obj->traced && !list_containers)
4529 needed->obj->traced = true;
4530 path = needed->obj->path;
4534 name = obj->strtab + needed->name;
4535 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4537 fmt = is_lib ? fmt1 : fmt2;
4538 while ((c = *fmt++) != '\0') {
4564 rtld_putstr(main_local);
4567 rtld_putstr(obj_main->path);
4574 rtld_printf("%d", sodp->sod_major);
4577 rtld_printf("%d", sodp->sod_minor);
4584 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4597 * Unload a dlopened object and its dependencies from memory and from
4598 * our data structures. It is assumed that the DAG rooted in the
4599 * object has already been unreferenced, and that the object has a
4600 * reference count of 0.
4603 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4605 Obj_Entry marker, *obj, *next;
4607 assert(root->refcount == 0);
4610 * Pass over the DAG removing unreferenced objects from
4611 * appropriate lists.
4613 unlink_object(root);
4615 /* Unmap all objects that are no longer referenced. */
4616 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4617 next = TAILQ_NEXT(obj, next);
4618 if (obj->marker || obj->refcount != 0)
4620 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4621 obj->mapsize, 0, obj->path);
4622 dbg("unloading \"%s\"", obj->path);
4624 * Unlink the object now to prevent new references from
4625 * being acquired while the bind lock is dropped in
4626 * recursive dlclose() invocations.
4628 TAILQ_REMOVE(&obj_list, obj, next);
4631 if (obj->filtees_loaded) {
4633 init_marker(&marker);
4634 TAILQ_INSERT_BEFORE(next, &marker, next);
4635 unload_filtees(obj, lockstate);
4636 next = TAILQ_NEXT(&marker, next);
4637 TAILQ_REMOVE(&obj_list, &marker, next);
4639 unload_filtees(obj, lockstate);
4641 release_object(obj);
4646 unlink_object(Obj_Entry *root)
4650 if (root->refcount == 0) {
4651 /* Remove the object from the RTLD_GLOBAL list. */
4652 objlist_remove(&list_global, root);
4654 /* Remove the object from all objects' DAG lists. */
4655 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4656 objlist_remove(&elm->obj->dldags, root);
4657 if (elm->obj != root)
4658 unlink_object(elm->obj);
4664 ref_dag(Obj_Entry *root)
4668 assert(root->dag_inited);
4669 STAILQ_FOREACH(elm, &root->dagmembers, link)
4670 elm->obj->refcount++;
4674 unref_dag(Obj_Entry *root)
4678 assert(root->dag_inited);
4679 STAILQ_FOREACH(elm, &root->dagmembers, link)
4680 elm->obj->refcount--;
4684 * Common code for MD __tls_get_addr().
4686 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4688 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4690 Elf_Addr *newdtv, *dtv;
4691 RtldLockState lockstate;
4695 /* Check dtv generation in case new modules have arrived */
4696 if (dtv[0] != tls_dtv_generation) {
4697 wlock_acquire(rtld_bind_lock, &lockstate);
4698 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4700 if (to_copy > tls_max_index)
4701 to_copy = tls_max_index;
4702 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4703 newdtv[0] = tls_dtv_generation;
4704 newdtv[1] = tls_max_index;
4706 lock_release(rtld_bind_lock, &lockstate);
4707 dtv = *dtvp = newdtv;
4710 /* Dynamically allocate module TLS if necessary */
4711 if (dtv[index + 1] == 0) {
4712 /* Signal safe, wlock will block out signals. */
4713 wlock_acquire(rtld_bind_lock, &lockstate);
4714 if (!dtv[index + 1])
4715 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4716 lock_release(rtld_bind_lock, &lockstate);
4718 return ((void *)(dtv[index + 1] + offset));
4722 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4727 /* Check dtv generation in case new modules have arrived */
4728 if (__predict_true(dtv[0] == tls_dtv_generation &&
4729 dtv[index + 1] != 0))
4730 return ((void *)(dtv[index + 1] + offset));
4731 return (tls_get_addr_slow(dtvp, index, offset));
4734 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4735 defined(__powerpc__) || defined(__riscv)
4738 * Return pointer to allocated TLS block
4741 get_tls_block_ptr(void *tcb, size_t tcbsize)
4743 size_t extra_size, post_size, pre_size, tls_block_size;
4744 size_t tls_init_align;
4746 tls_init_align = MAX(obj_main->tlsalign, 1);
4748 /* Compute fragments sizes. */
4749 extra_size = tcbsize - TLS_TCB_SIZE;
4750 post_size = calculate_tls_post_size(tls_init_align);
4751 tls_block_size = tcbsize + post_size;
4752 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4754 return ((char *)tcb - pre_size - extra_size);
4758 * Allocate Static TLS using the Variant I method.
4760 * For details on the layout, see lib/libc/gen/tls.c.
4762 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4763 * it is based on tls_last_offset, and TLS offsets here are really TCB
4764 * offsets, whereas libc's tls_static_space is just the executable's static
4768 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4772 Elf_Addr *dtv, **tcb;
4775 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4776 size_t tls_init_align;
4778 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4781 assert(tcbsize >= TLS_TCB_SIZE);
4782 maxalign = MAX(tcbalign, tls_static_max_align);
4783 tls_init_align = MAX(obj_main->tlsalign, 1);
4785 /* Compute fragmets sizes. */
4786 extra_size = tcbsize - TLS_TCB_SIZE;
4787 post_size = calculate_tls_post_size(tls_init_align);
4788 tls_block_size = tcbsize + post_size;
4789 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4790 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4792 /* Allocate whole TLS block */
4793 tls_block = malloc_aligned(tls_block_size, maxalign);
4794 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4796 if (oldtcb != NULL) {
4797 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4799 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4801 /* Adjust the DTV. */
4803 for (i = 0; i < dtv[1]; i++) {
4804 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4805 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4806 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4810 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4812 dtv[0] = tls_dtv_generation;
4813 dtv[1] = tls_max_index;
4815 for (obj = globallist_curr(objs); obj != NULL;
4816 obj = globallist_next(obj)) {
4817 if (obj->tlsoffset > 0) {
4818 addr = (Elf_Addr)tcb + obj->tlsoffset;
4819 if (obj->tlsinitsize > 0)
4820 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4821 if (obj->tlssize > obj->tlsinitsize)
4822 memset((void*)(addr + obj->tlsinitsize), 0,
4823 obj->tlssize - obj->tlsinitsize);
4824 dtv[obj->tlsindex + 1] = addr;
4833 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
4836 Elf_Addr tlsstart, tlsend;
4838 size_t dtvsize, i, tls_init_align;
4840 assert(tcbsize >= TLS_TCB_SIZE);
4841 tls_init_align = MAX(obj_main->tlsalign, 1);
4843 /* Compute fragments sizes. */
4844 post_size = calculate_tls_post_size(tls_init_align);
4846 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
4847 tlsend = (Elf_Addr)tcb + tls_static_space;
4849 dtv = *(Elf_Addr **)tcb;
4851 for (i = 0; i < dtvsize; i++) {
4852 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4853 free((void*)dtv[i+2]);
4857 free_aligned(get_tls_block_ptr(tcb, tcbsize));
4862 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4865 * Allocate Static TLS using the Variant II method.
4868 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4871 size_t size, ralign;
4873 Elf_Addr *dtv, *olddtv;
4874 Elf_Addr segbase, oldsegbase, addr;
4878 if (tls_static_max_align > ralign)
4879 ralign = tls_static_max_align;
4880 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4882 assert(tcbsize >= 2*sizeof(Elf_Addr));
4883 tls = malloc_aligned(size, ralign);
4884 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4886 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4887 ((Elf_Addr*)segbase)[0] = segbase;
4888 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4890 dtv[0] = tls_dtv_generation;
4891 dtv[1] = tls_max_index;
4895 * Copy the static TLS block over whole.
4897 oldsegbase = (Elf_Addr) oldtls;
4898 memcpy((void *)(segbase - tls_static_space),
4899 (const void *)(oldsegbase - tls_static_space),
4903 * If any dynamic TLS blocks have been created tls_get_addr(),
4906 olddtv = ((Elf_Addr**)oldsegbase)[1];
4907 for (i = 0; i < olddtv[1]; i++) {
4908 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4909 dtv[i+2] = olddtv[i+2];
4915 * We assume that this block was the one we created with
4916 * allocate_initial_tls().
4918 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4920 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4921 if (obj->marker || obj->tlsoffset == 0)
4923 addr = segbase - obj->tlsoffset;
4924 memset((void*)(addr + obj->tlsinitsize),
4925 0, obj->tlssize - obj->tlsinitsize);
4927 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4928 obj->static_tls_copied = true;
4930 dtv[obj->tlsindex + 1] = addr;
4934 return (void*) segbase;
4938 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
4941 size_t size, ralign;
4943 Elf_Addr tlsstart, tlsend;
4946 * Figure out the size of the initial TLS block so that we can
4947 * find stuff which ___tls_get_addr() allocated dynamically.
4950 if (tls_static_max_align > ralign)
4951 ralign = tls_static_max_align;
4952 size = round(tls_static_space, ralign);
4954 dtv = ((Elf_Addr**)tls)[1];
4956 tlsend = (Elf_Addr) tls;
4957 tlsstart = tlsend - size;
4958 for (i = 0; i < dtvsize; i++) {
4959 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4960 free_aligned((void *)dtv[i + 2]);
4964 free_aligned((void *)tlsstart);
4971 * Allocate TLS block for module with given index.
4974 allocate_module_tls(int index)
4979 TAILQ_FOREACH(obj, &obj_list, next) {
4982 if (obj->tlsindex == index)
4986 _rtld_error("Can't find module with TLS index %d", index);
4990 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4991 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4992 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4998 allocate_tls_offset(Obj_Entry *obj)
5005 if (obj->tlssize == 0) {
5006 obj->tls_done = true;
5010 if (tls_last_offset == 0)
5011 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
5013 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5014 obj->tlssize, obj->tlsalign);
5017 * If we have already fixed the size of the static TLS block, we
5018 * must stay within that size. When allocating the static TLS, we
5019 * leave a small amount of space spare to be used for dynamically
5020 * loading modules which use static TLS.
5022 if (tls_static_space != 0) {
5023 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5025 } else if (obj->tlsalign > tls_static_max_align) {
5026 tls_static_max_align = obj->tlsalign;
5029 tls_last_offset = obj->tlsoffset = off;
5030 tls_last_size = obj->tlssize;
5031 obj->tls_done = true;
5037 free_tls_offset(Obj_Entry *obj)
5041 * If we were the last thing to allocate out of the static TLS
5042 * block, we give our space back to the 'allocator'. This is a
5043 * simplistic workaround to allow libGL.so.1 to be loaded and
5044 * unloaded multiple times.
5046 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5047 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5048 tls_last_offset -= obj->tlssize;
5054 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5057 RtldLockState lockstate;
5059 wlock_acquire(rtld_bind_lock, &lockstate);
5060 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5062 lock_release(rtld_bind_lock, &lockstate);
5067 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5069 RtldLockState lockstate;
5071 wlock_acquire(rtld_bind_lock, &lockstate);
5072 free_tls(tcb, tcbsize, tcbalign);
5073 lock_release(rtld_bind_lock, &lockstate);
5077 object_add_name(Obj_Entry *obj, const char *name)
5083 entry = malloc(sizeof(Name_Entry) + len);
5085 if (entry != NULL) {
5086 strcpy(entry->name, name);
5087 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5092 object_match_name(const Obj_Entry *obj, const char *name)
5096 STAILQ_FOREACH(entry, &obj->names, link) {
5097 if (strcmp(name, entry->name) == 0)
5104 locate_dependency(const Obj_Entry *obj, const char *name)
5106 const Objlist_Entry *entry;
5107 const Needed_Entry *needed;
5109 STAILQ_FOREACH(entry, &list_main, link) {
5110 if (object_match_name(entry->obj, name))
5114 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5115 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5116 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5118 * If there is DT_NEEDED for the name we are looking for,
5119 * we are all set. Note that object might not be found if
5120 * dependency was not loaded yet, so the function can
5121 * return NULL here. This is expected and handled
5122 * properly by the caller.
5124 return (needed->obj);
5127 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5133 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5134 const Elf_Vernaux *vna)
5136 const Elf_Verdef *vd;
5137 const char *vername;
5139 vername = refobj->strtab + vna->vna_name;
5140 vd = depobj->verdef;
5142 _rtld_error("%s: version %s required by %s not defined",
5143 depobj->path, vername, refobj->path);
5147 if (vd->vd_version != VER_DEF_CURRENT) {
5148 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5149 depobj->path, vd->vd_version);
5152 if (vna->vna_hash == vd->vd_hash) {
5153 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5154 ((const char *)vd + vd->vd_aux);
5155 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5158 if (vd->vd_next == 0)
5160 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5162 if (vna->vna_flags & VER_FLG_WEAK)
5164 _rtld_error("%s: version %s required by %s not found",
5165 depobj->path, vername, refobj->path);
5170 rtld_verify_object_versions(Obj_Entry *obj)
5172 const Elf_Verneed *vn;
5173 const Elf_Verdef *vd;
5174 const Elf_Verdaux *vda;
5175 const Elf_Vernaux *vna;
5176 const Obj_Entry *depobj;
5177 int maxvernum, vernum;
5179 if (obj->ver_checked)
5181 obj->ver_checked = true;
5185 * Walk over defined and required version records and figure out
5186 * max index used by any of them. Do very basic sanity checking
5190 while (vn != NULL) {
5191 if (vn->vn_version != VER_NEED_CURRENT) {
5192 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5193 obj->path, vn->vn_version);
5196 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5198 vernum = VER_NEED_IDX(vna->vna_other);
5199 if (vernum > maxvernum)
5201 if (vna->vna_next == 0)
5203 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5205 if (vn->vn_next == 0)
5207 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5211 while (vd != NULL) {
5212 if (vd->vd_version != VER_DEF_CURRENT) {
5213 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5214 obj->path, vd->vd_version);
5217 vernum = VER_DEF_IDX(vd->vd_ndx);
5218 if (vernum > maxvernum)
5220 if (vd->vd_next == 0)
5222 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5229 * Store version information in array indexable by version index.
5230 * Verify that object version requirements are satisfied along the
5233 obj->vernum = maxvernum + 1;
5234 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5237 while (vd != NULL) {
5238 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5239 vernum = VER_DEF_IDX(vd->vd_ndx);
5240 assert(vernum <= maxvernum);
5241 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5242 obj->vertab[vernum].hash = vd->vd_hash;
5243 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5244 obj->vertab[vernum].file = NULL;
5245 obj->vertab[vernum].flags = 0;
5247 if (vd->vd_next == 0)
5249 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5253 while (vn != NULL) {
5254 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5257 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5259 if (check_object_provided_version(obj, depobj, vna))
5261 vernum = VER_NEED_IDX(vna->vna_other);
5262 assert(vernum <= maxvernum);
5263 obj->vertab[vernum].hash = vna->vna_hash;
5264 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5265 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5266 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5267 VER_INFO_HIDDEN : 0;
5268 if (vna->vna_next == 0)
5270 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5272 if (vn->vn_next == 0)
5274 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5280 rtld_verify_versions(const Objlist *objlist)
5282 Objlist_Entry *entry;
5286 STAILQ_FOREACH(entry, objlist, link) {
5288 * Skip dummy objects or objects that have their version requirements
5291 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5293 if (rtld_verify_object_versions(entry->obj) == -1) {
5295 if (ld_tracing == NULL)
5299 if (rc == 0 || ld_tracing != NULL)
5300 rc = rtld_verify_object_versions(&obj_rtld);
5305 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5310 vernum = VER_NDX(obj->versyms[symnum]);
5311 if (vernum >= obj->vernum) {
5312 _rtld_error("%s: symbol %s has wrong verneed value %d",
5313 obj->path, obj->strtab + symnum, vernum);
5314 } else if (obj->vertab[vernum].hash != 0) {
5315 return &obj->vertab[vernum];
5322 _rtld_get_stack_prot(void)
5325 return (stack_prot);
5329 _rtld_is_dlopened(void *arg)
5332 RtldLockState lockstate;
5335 rlock_acquire(rtld_bind_lock, &lockstate);
5338 obj = obj_from_addr(arg);
5340 _rtld_error("No shared object contains address");
5341 lock_release(rtld_bind_lock, &lockstate);
5344 res = obj->dlopened ? 1 : 0;
5345 lock_release(rtld_bind_lock, &lockstate);
5350 obj_remap_relro(Obj_Entry *obj, int prot)
5353 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5355 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5356 obj->path, prot, rtld_strerror(errno));
5363 obj_disable_relro(Obj_Entry *obj)
5366 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5370 obj_enforce_relro(Obj_Entry *obj)
5373 return (obj_remap_relro(obj, PROT_READ));
5377 map_stacks_exec(RtldLockState *lockstate)
5379 void (*thr_map_stacks_exec)(void);
5381 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5383 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5384 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5385 if (thr_map_stacks_exec != NULL) {
5386 stack_prot |= PROT_EXEC;
5387 thr_map_stacks_exec();
5392 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5396 void (*distrib)(size_t, void *, size_t, size_t);
5398 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5399 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5400 if (distrib == NULL)
5402 STAILQ_FOREACH(elm, list, link) {
5404 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5406 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5408 obj->static_tls_copied = true;
5413 symlook_init(SymLook *dst, const char *name)
5416 bzero(dst, sizeof(*dst));
5418 dst->hash = elf_hash(name);
5419 dst->hash_gnu = gnu_hash(name);
5423 symlook_init_from_req(SymLook *dst, const SymLook *src)
5426 dst->name = src->name;
5427 dst->hash = src->hash;
5428 dst->hash_gnu = src->hash_gnu;
5429 dst->ventry = src->ventry;
5430 dst->flags = src->flags;
5431 dst->defobj_out = NULL;
5432 dst->sym_out = NULL;
5433 dst->lockstate = src->lockstate;
5437 open_binary_fd(const char *argv0, bool search_in_path)
5439 char *pathenv, *pe, binpath[PATH_MAX];
5442 if (search_in_path && strchr(argv0, '/') == NULL) {
5443 pathenv = getenv("PATH");
5444 if (pathenv == NULL) {
5445 _rtld_error("-p and no PATH environment variable");
5448 pathenv = strdup(pathenv);
5449 if (pathenv == NULL) {
5450 _rtld_error("Cannot allocate memory");
5455 while ((pe = strsep(&pathenv, ":")) != NULL) {
5456 if (strlcpy(binpath, pe, sizeof(binpath)) >=
5459 if (binpath[0] != '\0' &&
5460 strlcat(binpath, "/", sizeof(binpath)) >=
5463 if (strlcat(binpath, argv0, sizeof(binpath)) >=
5466 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5467 if (fd != -1 || errno != ENOENT)
5472 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5476 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5483 * Parse a set of command-line arguments.
5486 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp)
5489 int fd, i, j, arglen;
5492 dbg("Parsing command-line arguments");
5496 for (i = 1; i < argc; i++ ) {
5498 dbg("argv[%d]: '%s'", i, arg);
5501 * rtld arguments end with an explicit "--" or with the first
5502 * non-prefixed argument.
5504 if (strcmp(arg, "--") == 0) {
5512 * All other arguments are single-character options that can
5513 * be combined, so we need to search through `arg` for them.
5515 arglen = strlen(arg);
5516 for (j = 1; j < arglen; j++) {
5519 print_usage(argv[0]);
5521 } else if (opt == 'f') {
5523 * -f XX can be used to specify a descriptor for the
5524 * binary named at the command line (i.e., the later
5525 * argument will specify the process name but the
5526 * descriptor is what will actually be executed)
5528 if (j != arglen - 1) {
5529 /* -f must be the last option in, e.g., -abcf */
5530 _rtld_error("Invalid options: %s", arg);
5534 fd = parse_integer(argv[i]);
5536 _rtld_error("Invalid file descriptor: '%s'",
5542 } else if (opt == 'p') {
5545 _rtld_error("Invalid argument: '%s'", arg);
5546 print_usage(argv[0]);
5556 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5559 parse_integer(const char *str)
5561 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5568 for (c = *str; c != '\0'; c = *++str) {
5569 if (c < '0' || c > '9')
5576 /* Make sure we actually parsed something. */
5583 print_usage(const char *argv0)
5586 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n"
5589 " -h Display this help message\n"
5590 " -p Search in PATH for named binary\n"
5591 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5592 " -- End of RTLD options\n"
5593 " <binary> Name of process to execute\n"
5594 " <args> Arguments to the executed process\n", argv0);
5598 * Overrides for libc_pic-provided functions.
5602 __getosreldate(void)
5612 oid[1] = KERN_OSRELDATE;
5614 len = sizeof(osrel);
5615 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5616 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5628 void (*__cleanup)(void);
5629 int __isthreaded = 0;
5630 int _thread_autoinit_dummy_decl = 1;
5633 * No unresolved symbols for rtld.
5636 __pthread_cxa_finalize(struct dl_phdr_info *a __unused)
5641 rtld_strerror(int errnum)
5644 if (errnum < 0 || errnum >= sys_nerr)
5645 return ("Unknown error");
5646 return (sys_errlist[errnum]);
5650 * No ifunc relocations.
5653 memset(void *dest, int c, size_t len)
5657 for (i = 0; i < len; i++)
5658 ((char *)dest)[i] = c;
5663 bzero(void *dest, size_t len)
5667 for (i = 0; i < len; i++)
5668 ((char *)dest)[i] = 0;
5673 malloc(size_t nbytes)
5676 return (__crt_malloc(nbytes));
5680 calloc(size_t num, size_t size)
5683 return (__crt_calloc(num, size));
5694 realloc(void *cp, size_t nbytes)
5697 return (__crt_realloc(cp, nbytes));