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_utrace.h"
73 typedef void (*func_ptr_type)(void);
74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
77 /* Variables that cannot be static: */
78 extern struct r_debug r_debug; /* For GDB */
79 extern int _thread_autoinit_dummy_decl;
80 extern char* __progname;
81 extern void (*__cleanup)(void);
85 * Function declarations.
87 static const char *basename(const char *);
88 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
89 const Elf_Dyn **, const Elf_Dyn **);
90 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
92 static void digest_dynamic(Obj_Entry *, int);
93 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
94 static Obj_Entry *dlcheck(void *);
95 static int dlclose_locked(void *, RtldLockState *);
96 static Obj_Entry *dlopen_object(int, const char *name, int fd,
97 Obj_Entry *refobj, int lo_flags, int mode, RtldLockState *lockstate);
98 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
99 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
100 static bool donelist_check(DoneList *, const Obj_Entry *);
101 static void errmsg_restore(char *);
102 static char *errmsg_save(void);
103 static void *fill_search_info(const char *, size_t, void *);
104 static char *find_library(const char *, const Obj_Entry *, int *);
105 static const char *gethints(bool);
106 static void hold_object(Obj_Entry *);
107 static void unhold_object(Obj_Entry *);
108 static void init_dag(Obj_Entry *);
109 static void init_marker(Obj_Entry *);
110 static void init_pagesizes(Elf_Auxinfo **aux_info);
111 static void init_rtld(caddr_t, Elf_Auxinfo **);
112 static void initlist_add_neededs(Needed_Entry *, Objlist *);
113 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
114 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
115 static void linkmap_add(Obj_Entry *);
116 static void linkmap_delete(Obj_Entry *);
117 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
118 static void unload_filtees(Obj_Entry *, RtldLockState *);
119 static int load_needed_objects(Obj_Entry *, int);
120 static int load_preload_objects(void);
121 static Obj_Entry *load_object(int, const char *, int, const Obj_Entry *, int);
122 static void map_stacks_exec(RtldLockState *);
123 static int obj_disable_relro(Obj_Entry *);
124 static int obj_enforce_relro(Obj_Entry *);
125 static Obj_Entry *obj_from_addr(const void *);
126 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
127 static void objlist_call_init(Objlist *, RtldLockState *);
128 static void objlist_clear(Objlist *);
129 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
130 static void objlist_init(Objlist *);
131 static void objlist_push_head(Objlist *, Obj_Entry *);
132 static void objlist_push_tail(Objlist *, Obj_Entry *);
133 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
134 static void objlist_remove(Objlist *, Obj_Entry *);
135 static int open_binary_fd(const char *argv0, bool search_in_path);
136 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp);
137 static int parse_integer(const char *);
138 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
139 static void print_usage(const char *argv0);
140 static void release_object(Obj_Entry *);
141 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
142 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
143 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
144 int flags, RtldLockState *lockstate);
145 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
147 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
148 static int rtld_dirname(const char *, char *);
149 static int rtld_dirname_abs(const char *, char *);
150 static void *rtld_dlopen(int, const char *name, int fd, int mode);
151 static void rtld_exit(void);
152 static char *search_library_path(const char *, const char *, const char *,
154 static char *search_library_pathfds(const char *, const char *, int *);
155 static const void **get_program_var_addr(const char *, RtldLockState *);
156 static void set_program_var(const char *, const void *);
157 static int symlook_default(SymLook *, const Obj_Entry *refobj);
158 static int symlook_global(SymLook *, DoneList *);
159 static void symlook_init_from_req(SymLook *, const SymLook *);
160 static int symlook_list(SymLook *, const Objlist *, DoneList *);
161 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
162 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
163 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
164 static void trace_loaded_objects(Obj_Entry *);
165 static void unlink_object(Obj_Entry *);
166 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
167 static void unref_dag(Obj_Entry *);
168 static void ref_dag(Obj_Entry *);
169 static char *origin_subst_one(Obj_Entry *, char *, const char *,
171 static char *origin_subst(Obj_Entry *, const char *);
172 static bool obj_resolve_origin(Obj_Entry *obj);
173 static void preinit_main(void);
174 static int rtld_verify_versions(const Objlist *);
175 static int rtld_verify_object_versions(Obj_Entry *);
176 static void object_add_name(Obj_Entry *, const char *);
177 static int object_match_name(const Obj_Entry *, const char *);
178 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
179 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
180 struct dl_phdr_info *phdr_info);
181 static uint32_t gnu_hash(const char *);
182 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
183 const unsigned long);
185 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
186 void _r_debug_postinit(struct link_map *) __noinline __exported;
188 int __sys_openat(int, const char *, int, ...);
193 static char *error_message; /* Message for dlerror(), or NULL */
194 struct r_debug r_debug __exported; /* for GDB; */
195 static bool libmap_disable; /* Disable libmap */
196 static bool ld_loadfltr; /* Immediate filters processing */
197 static char *libmap_override; /* Maps to use in addition to libmap.conf */
198 static bool trust; /* False for setuid and setgid programs */
199 static bool dangerous_ld_env; /* True if environment variables have been
200 used to affect the libraries loaded */
201 bool ld_bind_not; /* Disable PLT update */
202 static char *ld_bind_now; /* Environment variable for immediate binding */
203 static char *ld_debug; /* Environment variable for debugging */
204 static char *ld_library_path; /* Environment variable for search path */
205 static char *ld_library_dirs; /* Environment variable for library descriptors */
206 static char *ld_preload; /* Environment variable for libraries to
208 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
209 static const char *ld_tracing; /* Called from ldd to print libs */
210 static char *ld_utrace; /* Use utrace() to log events. */
211 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
212 static Obj_Entry *obj_main; /* The main program shared object */
213 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
214 static unsigned int obj_count; /* Number of objects in obj_list */
215 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
217 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
218 STAILQ_HEAD_INITIALIZER(list_global);
219 static Objlist list_main = /* Objects loaded at program startup */
220 STAILQ_HEAD_INITIALIZER(list_main);
221 static Objlist list_fini = /* Objects needing fini() calls */
222 STAILQ_HEAD_INITIALIZER(list_fini);
224 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
226 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
228 extern Elf_Dyn _DYNAMIC;
229 #pragma weak _DYNAMIC
231 int dlclose(void *) __exported;
232 char *dlerror(void) __exported;
233 void *dlopen(const char *, int) __exported;
234 void *dlopenat(int, const char *, int) __exported;
235 void *fdlopen(int, int) __exported;
236 void *dlsym(void *, const char *) __exported;
237 dlfunc_t dlfunc(void *, const char *) __exported;
238 void *dlvsym(void *, const char *, const char *) __exported;
239 int dladdr(const void *, Dl_info *) __exported;
240 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
241 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
242 int dlinfo(void *, int , void *) __exported;
243 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
244 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
245 int _rtld_get_stack_prot(void) __exported;
246 int _rtld_is_dlopened(void *) __exported;
247 void _rtld_error(const char *, ...) __exported;
249 /* Only here to fix -Wmissing-prototypes warnings */
250 int __getosreldate(void);
251 void __pthread_cxa_finalize(struct dl_phdr_info *a);
252 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
253 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
257 static int osreldate;
260 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
261 static int max_stack_flags;
264 * Global declarations normally provided by crt1. The dynamic linker is
265 * not built with crt1, so we have to provide them ourselves.
271 * Used to pass argc, argv to init functions.
277 * Globals to control TLS allocation.
279 size_t tls_last_offset; /* Static TLS offset of last module */
280 size_t tls_last_size; /* Static TLS size of last module */
281 size_t tls_static_space; /* Static TLS space allocated */
282 static size_t tls_static_max_align;
283 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
284 int tls_max_index = 1; /* Largest module index allocated */
286 static bool ld_library_path_rpath = false;
289 * Globals for path names, and such
291 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
292 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
293 const char *ld_path_rtld = _PATH_RTLD;
294 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
295 const char *ld_env_prefix = LD_;
298 * Fill in a DoneList with an allocation large enough to hold all of
299 * the currently-loaded objects. Keep this as a macro since it calls
300 * alloca and we want that to occur within the scope of the caller.
302 #define donelist_init(dlp) \
303 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
304 assert((dlp)->objs != NULL), \
305 (dlp)->num_alloc = obj_count, \
308 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
309 if (ld_utrace != NULL) \
310 ld_utrace_log(e, h, mb, ms, r, n); \
314 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
315 int refcnt, const char *name)
317 struct utrace_rtld ut;
318 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
320 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
323 ut.mapbase = mapbase;
324 ut.mapsize = mapsize;
326 bzero(ut.name, sizeof(ut.name));
328 strlcpy(ut.name, name, sizeof(ut.name));
329 utrace(&ut, sizeof(ut));
332 #ifdef RTLD_VARIANT_ENV_NAMES
334 * construct the env variable based on the type of binary that's
337 static inline const char *
340 static char buffer[128];
342 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
343 strlcat(buffer, var, sizeof(buffer));
351 * Main entry point for dynamic linking. The first argument is the
352 * stack pointer. The stack is expected to be laid out as described
353 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
354 * Specifically, the stack pointer points to a word containing
355 * ARGC. Following that in the stack is a null-terminated sequence
356 * of pointers to argument strings. Then comes a null-terminated
357 * sequence of pointers to environment strings. Finally, there is a
358 * sequence of "auxiliary vector" entries.
360 * The second argument points to a place to store the dynamic linker's
361 * exit procedure pointer and the third to a place to store the main
364 * The return value is the main program's entry point.
367 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
369 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
370 Objlist_Entry *entry;
371 Obj_Entry *last_interposer, *obj, *preload_tail;
372 const Elf_Phdr *phdr;
374 RtldLockState lockstate;
377 char **argv, **env, **envp, *kexecpath, *library_path_rpath;
380 char buf[MAXPATHLEN];
381 int argc, fd, i, phnum, rtld_argc;
382 bool dir_enable, explicit_fd, search_in_path;
385 * On entry, the dynamic linker itself has not been relocated yet.
386 * Be very careful not to reference any global data until after
387 * init_rtld has returned. It is OK to reference file-scope statics
388 * and string constants, and to call static and global functions.
391 /* Find the auxiliary vector on the stack. */
395 sp += argc + 1; /* Skip over arguments and NULL terminator */
397 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
399 aux = (Elf_Auxinfo *) sp;
401 /* Digest the auxiliary vector. */
402 for (i = 0; i < AT_COUNT; i++)
404 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
405 if (auxp->a_type < AT_COUNT)
406 aux_info[auxp->a_type] = auxp;
409 /* Initialize and relocate ourselves. */
410 assert(aux_info[AT_BASE] != NULL);
411 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
413 __progname = obj_rtld.path;
414 argv0 = argv[0] != NULL ? argv[0] : "(null)";
419 trust = !issetugid();
421 md_abi_variant_hook(aux_info);
424 if (aux_info[AT_EXECFD] != NULL) {
425 fd = aux_info[AT_EXECFD]->a_un.a_val;
427 assert(aux_info[AT_PHDR] != NULL);
428 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
429 if (phdr == obj_rtld.phdr) {
431 _rtld_error("Tainted process refusing to run binary %s",
435 dbg("opening main program in direct exec mode");
437 rtld_argc = parse_args(argv, argc, &search_in_path, &fd);
438 argv0 = argv[rtld_argc];
439 explicit_fd = (fd != -1);
441 fd = open_binary_fd(argv0, search_in_path);
442 if (fstat(fd, &st) == -1) {
443 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
444 explicit_fd ? "user-provided descriptor" : argv0,
445 rtld_strerror(errno));
450 * Rough emulation of the permission checks done by
451 * execve(2), only Unix DACs are checked, ACLs are
452 * ignored. Preserve the semantic of disabling owner
453 * to execute if owner x bit is cleared, even if
454 * others x bit is enabled.
455 * mmap(2) does not allow to mmap with PROT_EXEC if
456 * binary' file comes from noexec mount. We cannot
457 * set VV_TEXT on the binary.
460 if (st.st_uid == geteuid()) {
461 if ((st.st_mode & S_IXUSR) != 0)
463 } else if (st.st_gid == getegid()) {
464 if ((st.st_mode & S_IXGRP) != 0)
466 } else if ((st.st_mode & S_IXOTH) != 0) {
470 _rtld_error("No execute permission for binary %s",
476 * For direct exec mode, argv[0] is the interpreter
477 * name, we must remove it and shift arguments left
478 * before invoking binary main. Since stack layout
479 * places environment pointers and aux vectors right
480 * after the terminating NULL, we must shift
481 * environment and aux as well.
483 main_argc = argc - rtld_argc;
484 for (i = 0; i <= main_argc; i++)
485 argv[i] = argv[i + rtld_argc];
487 environ = env = envp = argv + main_argc + 1;
489 *envp = *(envp + rtld_argc);
491 } while (*envp != NULL);
492 aux = auxp = (Elf_Auxinfo *)envp;
493 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
494 for (;; auxp++, auxpf++) {
496 if (auxp->a_type == AT_NULL)
500 _rtld_error("No binary");
506 ld_bind_now = getenv(_LD("BIND_NOW"));
509 * If the process is tainted, then we un-set the dangerous environment
510 * variables. The process will be marked as tainted until setuid(2)
511 * is called. If any child process calls setuid(2) we do not want any
512 * future processes to honor the potentially un-safe variables.
515 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
516 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
517 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
518 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
519 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
520 _rtld_error("environment corrupt; aborting");
524 ld_debug = getenv(_LD("DEBUG"));
525 if (ld_bind_now == NULL)
526 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
527 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
528 libmap_override = getenv(_LD("LIBMAP"));
529 ld_library_path = getenv(_LD("LIBRARY_PATH"));
530 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
531 ld_preload = getenv(_LD("PRELOAD"));
532 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
533 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
534 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
535 if (library_path_rpath != NULL) {
536 if (library_path_rpath[0] == 'y' ||
537 library_path_rpath[0] == 'Y' ||
538 library_path_rpath[0] == '1')
539 ld_library_path_rpath = true;
541 ld_library_path_rpath = false;
543 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
544 (ld_library_path != NULL) || (ld_preload != NULL) ||
545 (ld_elf_hints_path != NULL) || ld_loadfltr;
546 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
547 ld_utrace = getenv(_LD("UTRACE"));
549 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
550 ld_elf_hints_path = ld_elf_hints_default;
552 if (ld_debug != NULL && *ld_debug != '\0')
554 dbg("%s is initialized, base address = %p", __progname,
555 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
556 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
557 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
559 dbg("initializing thread locks");
563 * Load the main program, or process its program header if it is
566 if (fd != -1) { /* Load the main program. */
567 dbg("loading main program");
568 obj_main = map_object(fd, argv0, NULL);
570 if (obj_main == NULL)
572 max_stack_flags = obj_main->stack_flags;
573 } else { /* Main program already loaded. */
574 dbg("processing main program's program header");
575 assert(aux_info[AT_PHDR] != NULL);
576 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
577 assert(aux_info[AT_PHNUM] != NULL);
578 phnum = aux_info[AT_PHNUM]->a_un.a_val;
579 assert(aux_info[AT_PHENT] != NULL);
580 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
581 assert(aux_info[AT_ENTRY] != NULL);
582 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
583 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
587 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
588 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
589 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
590 if (kexecpath[0] == '/')
591 obj_main->path = kexecpath;
592 else if (getcwd(buf, sizeof(buf)) == NULL ||
593 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
594 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
595 obj_main->path = xstrdup(argv0);
597 obj_main->path = xstrdup(buf);
599 dbg("No AT_EXECPATH or direct exec");
600 obj_main->path = xstrdup(argv0);
602 dbg("obj_main path %s", obj_main->path);
603 obj_main->mainprog = true;
605 if (aux_info[AT_STACKPROT] != NULL &&
606 aux_info[AT_STACKPROT]->a_un.a_val != 0)
607 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
611 * Get the actual dynamic linker pathname from the executable if
612 * possible. (It should always be possible.) That ensures that
613 * gdb will find the right dynamic linker even if a non-standard
616 if (obj_main->interp != NULL &&
617 strcmp(obj_main->interp, obj_rtld.path) != 0) {
619 obj_rtld.path = xstrdup(obj_main->interp);
620 __progname = obj_rtld.path;
624 digest_dynamic(obj_main, 0);
625 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
626 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
627 obj_main->dynsymcount);
629 linkmap_add(obj_main);
630 linkmap_add(&obj_rtld);
632 /* Link the main program into the list of objects. */
633 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
637 /* Initialize a fake symbol for resolving undefined weak references. */
638 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
639 sym_zero.st_shndx = SHN_UNDEF;
640 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
643 libmap_disable = (bool)lm_init(libmap_override);
645 dbg("loading LD_PRELOAD libraries");
646 if (load_preload_objects() == -1)
648 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
650 dbg("loading needed objects");
651 if (load_needed_objects(obj_main, 0) == -1)
654 /* Make a list of all objects loaded at startup. */
655 last_interposer = obj_main;
656 TAILQ_FOREACH(obj, &obj_list, next) {
659 if (obj->z_interpose && obj != obj_main) {
660 objlist_put_after(&list_main, last_interposer, obj);
661 last_interposer = obj;
663 objlist_push_tail(&list_main, obj);
668 dbg("checking for required versions");
669 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
672 if (ld_tracing) { /* We're done */
673 trace_loaded_objects(obj_main);
677 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
678 dump_relocations(obj_main);
683 * Processing tls relocations requires having the tls offsets
684 * initialized. Prepare offsets before starting initial
685 * relocation processing.
687 dbg("initializing initial thread local storage offsets");
688 STAILQ_FOREACH(entry, &list_main, link) {
690 * Allocate all the initial objects out of the static TLS
691 * block even if they didn't ask for it.
693 allocate_tls_offset(entry->obj);
696 if (relocate_objects(obj_main,
697 ld_bind_now != NULL && *ld_bind_now != '\0',
698 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
701 dbg("doing copy relocations");
702 if (do_copy_relocations(obj_main) == -1)
705 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
706 dump_relocations(obj_main);
713 * Setup TLS for main thread. This must be done after the
714 * relocations are processed, since tls initialization section
715 * might be the subject for relocations.
717 dbg("initializing initial thread local storage");
718 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
720 dbg("initializing key program variables");
721 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
722 set_program_var("environ", env);
723 set_program_var("__elf_aux_vector", aux);
725 /* Make a list of init functions to call. */
726 objlist_init(&initlist);
727 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
728 preload_tail, &initlist);
730 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
732 map_stacks_exec(NULL);
734 if (!obj_main->crt_no_init) {
736 * Make sure we don't call the main program's init and fini
737 * functions for binaries linked with old crt1 which calls
740 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
741 obj_main->preinit_array = obj_main->init_array =
742 obj_main->fini_array = (Elf_Addr)NULL;
746 * Execute MD initializers required before we call the objects'
751 wlock_acquire(rtld_bind_lock, &lockstate);
753 dbg("resolving ifuncs");
754 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
755 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
758 if (obj_main->crt_no_init)
760 objlist_call_init(&initlist, &lockstate);
761 _r_debug_postinit(&obj_main->linkmap);
762 objlist_clear(&initlist);
763 dbg("loading filtees");
764 TAILQ_FOREACH(obj, &obj_list, next) {
767 if (ld_loadfltr || obj->z_loadfltr)
768 load_filtees(obj, 0, &lockstate);
771 dbg("enforcing main obj relro");
772 if (obj_enforce_relro(obj_main) == -1)
775 lock_release(rtld_bind_lock, &lockstate);
777 dbg("transferring control to program entry point = %p", obj_main->entry);
779 /* Return the exit procedure and the program entry point. */
780 *exit_proc = rtld_exit;
782 return (func_ptr_type) obj_main->entry;
786 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
791 ptr = (void *)make_function_pointer(def, obj);
792 target = call_ifunc_resolver(ptr);
793 return ((void *)target);
797 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
798 * Changes to this function should be applied there as well.
801 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
805 const Obj_Entry *defobj;
808 RtldLockState lockstate;
810 rlock_acquire(rtld_bind_lock, &lockstate);
811 if (sigsetjmp(lockstate.env, 0) != 0)
812 lock_upgrade(rtld_bind_lock, &lockstate);
814 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
816 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
818 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
819 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
823 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
824 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
826 target = (Elf_Addr)(defobj->relocbase + def->st_value);
828 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
829 defobj->strtab + def->st_name, basename(obj->path),
830 (void *)target, basename(defobj->path));
833 * Write the new contents for the jmpslot. Note that depending on
834 * architecture, the value which we need to return back to the
835 * lazy binding trampoline may or may not be the target
836 * address. The value returned from reloc_jmpslot() is the value
837 * that the trampoline needs.
839 target = reloc_jmpslot(where, target, defobj, obj, rel);
840 lock_release(rtld_bind_lock, &lockstate);
845 * Error reporting function. Use it like printf. If formats the message
846 * into a buffer, and sets things up so that the next call to dlerror()
847 * will return the message.
850 _rtld_error(const char *fmt, ...)
852 static char buf[512];
856 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
859 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
863 * Return a dynamically-allocated copy of the current error message, if any.
868 return error_message == NULL ? NULL : xstrdup(error_message);
872 * Restore the current error message from a copy which was previously saved
873 * by errmsg_save(). The copy is freed.
876 errmsg_restore(char *saved_msg)
878 if (saved_msg == NULL)
879 error_message = NULL;
881 _rtld_error("%s", saved_msg);
887 basename(const char *name)
889 const char *p = strrchr(name, '/');
890 return p != NULL ? p + 1 : name;
893 static struct utsname uts;
896 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
897 const char *subst, bool may_free)
899 char *p, *p1, *res, *resp;
900 int subst_len, kw_len, subst_count, old_len, new_len;
905 * First, count the number of the keyword occurrences, to
906 * preallocate the final string.
908 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
915 * If the keyword is not found, just return.
917 * Return non-substituted string if resolution failed. We
918 * cannot do anything more reasonable, the failure mode of the
919 * caller is unresolved library anyway.
921 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
922 return (may_free ? real : xstrdup(real));
924 subst = obj->origin_path;
927 * There is indeed something to substitute. Calculate the
928 * length of the resulting string, and allocate it.
930 subst_len = strlen(subst);
931 old_len = strlen(real);
932 new_len = old_len + (subst_len - kw_len) * subst_count;
933 res = xmalloc(new_len + 1);
936 * Now, execute the substitution loop.
938 for (p = real, resp = res, *resp = '\0';;) {
941 /* Copy the prefix before keyword. */
942 memcpy(resp, p, p1 - p);
944 /* Keyword replacement. */
945 memcpy(resp, subst, subst_len);
953 /* Copy to the end of string and finish. */
961 origin_subst(Obj_Entry *obj, const char *real)
963 char *res1, *res2, *res3, *res4;
965 if (obj == NULL || !trust)
966 return (xstrdup(real));
967 if (uts.sysname[0] == '\0') {
968 if (uname(&uts) != 0) {
969 _rtld_error("utsname failed: %d", errno);
973 /* __DECONST is safe here since without may_free real is unchanged */
974 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL,
976 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
977 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
978 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
985 const char *msg = dlerror();
989 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
990 rtld_fdputstr(STDERR_FILENO, msg);
991 rtld_fdputchar(STDERR_FILENO, '\n');
996 * Process a shared object's DYNAMIC section, and save the important
997 * information in its Obj_Entry structure.
1000 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1001 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1003 const Elf_Dyn *dynp;
1004 Needed_Entry **needed_tail = &obj->needed;
1005 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1006 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1007 const Elf_Hashelt *hashtab;
1008 const Elf32_Word *hashval;
1009 Elf32_Word bkt, nmaskwords;
1011 int plttype = DT_REL;
1015 *dyn_runpath = NULL;
1017 obj->bind_now = false;
1018 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
1019 switch (dynp->d_tag) {
1022 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1026 obj->relsize = dynp->d_un.d_val;
1030 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1034 obj->pltrel = (const Elf_Rel *)
1035 (obj->relocbase + dynp->d_un.d_ptr);
1039 obj->pltrelsize = dynp->d_un.d_val;
1043 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1047 obj->relasize = dynp->d_un.d_val;
1051 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1055 plttype = dynp->d_un.d_val;
1056 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1060 obj->symtab = (const Elf_Sym *)
1061 (obj->relocbase + dynp->d_un.d_ptr);
1065 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1069 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1073 obj->strsize = dynp->d_un.d_val;
1077 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1082 obj->verneednum = dynp->d_un.d_val;
1086 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1091 obj->verdefnum = dynp->d_un.d_val;
1095 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1101 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1103 obj->nbuckets = hashtab[0];
1104 obj->nchains = hashtab[1];
1105 obj->buckets = hashtab + 2;
1106 obj->chains = obj->buckets + obj->nbuckets;
1107 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1108 obj->buckets != NULL;
1114 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1116 obj->nbuckets_gnu = hashtab[0];
1117 obj->symndx_gnu = hashtab[1];
1118 nmaskwords = hashtab[2];
1119 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1120 obj->maskwords_bm_gnu = nmaskwords - 1;
1121 obj->shift2_gnu = hashtab[3];
1122 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1123 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1124 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1126 /* Number of bitmask words is required to be power of 2 */
1127 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1128 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1134 Needed_Entry *nep = NEW(Needed_Entry);
1135 nep->name = dynp->d_un.d_val;
1140 needed_tail = &nep->next;
1146 Needed_Entry *nep = NEW(Needed_Entry);
1147 nep->name = dynp->d_un.d_val;
1151 *needed_filtees_tail = nep;
1152 needed_filtees_tail = &nep->next;
1158 Needed_Entry *nep = NEW(Needed_Entry);
1159 nep->name = dynp->d_un.d_val;
1163 *needed_aux_filtees_tail = nep;
1164 needed_aux_filtees_tail = &nep->next;
1169 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1173 obj->textrel = true;
1177 obj->symbolic = true;
1182 * We have to wait until later to process this, because we
1183 * might not have gotten the address of the string table yet.
1193 *dyn_runpath = dynp;
1197 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1200 case DT_PREINIT_ARRAY:
1201 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1204 case DT_PREINIT_ARRAYSZ:
1205 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1209 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1212 case DT_INIT_ARRAYSZ:
1213 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1217 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1221 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1224 case DT_FINI_ARRAYSZ:
1225 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1229 * Don't process DT_DEBUG on MIPS as the dynamic section
1230 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1236 dbg("Filling in DT_DEBUG entry");
1237 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1242 if (dynp->d_un.d_val & DF_ORIGIN)
1243 obj->z_origin = true;
1244 if (dynp->d_un.d_val & DF_SYMBOLIC)
1245 obj->symbolic = true;
1246 if (dynp->d_un.d_val & DF_TEXTREL)
1247 obj->textrel = true;
1248 if (dynp->d_un.d_val & DF_BIND_NOW)
1249 obj->bind_now = true;
1250 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1254 case DT_MIPS_LOCAL_GOTNO:
1255 obj->local_gotno = dynp->d_un.d_val;
1258 case DT_MIPS_SYMTABNO:
1259 obj->symtabno = dynp->d_un.d_val;
1262 case DT_MIPS_GOTSYM:
1263 obj->gotsym = dynp->d_un.d_val;
1266 case DT_MIPS_RLD_MAP:
1267 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1270 case DT_MIPS_RLD_MAP_REL:
1271 // The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map
1272 // section relative to the address of the tag itself.
1273 *((Elf_Addr *)(__DECONST(char*, dynp) + dynp->d_un.d_val)) =
1274 (Elf_Addr) &r_debug;
1277 case DT_MIPS_PLTGOT:
1278 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase +
1284 #ifdef __powerpc64__
1285 case DT_PPC64_GLINK:
1286 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1291 if (dynp->d_un.d_val & DF_1_NOOPEN)
1292 obj->z_noopen = true;
1293 if (dynp->d_un.d_val & DF_1_ORIGIN)
1294 obj->z_origin = true;
1295 if (dynp->d_un.d_val & DF_1_GLOBAL)
1296 obj->z_global = true;
1297 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1298 obj->bind_now = true;
1299 if (dynp->d_un.d_val & DF_1_NODELETE)
1300 obj->z_nodelete = true;
1301 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1302 obj->z_loadfltr = true;
1303 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1304 obj->z_interpose = true;
1305 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1306 obj->z_nodeflib = true;
1311 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1318 obj->traced = false;
1320 if (plttype == DT_RELA) {
1321 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1323 obj->pltrelasize = obj->pltrelsize;
1324 obj->pltrelsize = 0;
1327 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1328 if (obj->valid_hash_sysv)
1329 obj->dynsymcount = obj->nchains;
1330 else if (obj->valid_hash_gnu) {
1331 obj->dynsymcount = 0;
1332 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1333 if (obj->buckets_gnu[bkt] == 0)
1335 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1338 while ((*hashval++ & 1u) == 0);
1340 obj->dynsymcount += obj->symndx_gnu;
1345 obj_resolve_origin(Obj_Entry *obj)
1348 if (obj->origin_path != NULL)
1350 obj->origin_path = xmalloc(PATH_MAX);
1351 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1355 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1356 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1359 if (obj->z_origin && !obj_resolve_origin(obj))
1362 if (dyn_runpath != NULL) {
1363 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1364 obj->runpath = origin_subst(obj, obj->runpath);
1365 } else if (dyn_rpath != NULL) {
1366 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1367 obj->rpath = origin_subst(obj, obj->rpath);
1369 if (dyn_soname != NULL)
1370 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1374 digest_dynamic(Obj_Entry *obj, int early)
1376 const Elf_Dyn *dyn_rpath;
1377 const Elf_Dyn *dyn_soname;
1378 const Elf_Dyn *dyn_runpath;
1380 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1381 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1385 * Process a shared object's program header. This is used only for the
1386 * main program, when the kernel has already loaded the main program
1387 * into memory before calling the dynamic linker. It creates and
1388 * returns an Obj_Entry structure.
1391 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1394 const Elf_Phdr *phlimit = phdr + phnum;
1396 Elf_Addr note_start, note_end;
1400 for (ph = phdr; ph < phlimit; ph++) {
1401 if (ph->p_type != PT_PHDR)
1405 obj->phsize = ph->p_memsz;
1406 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1410 obj->stack_flags = PF_X | PF_R | PF_W;
1412 for (ph = phdr; ph < phlimit; ph++) {
1413 switch (ph->p_type) {
1416 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1420 if (nsegs == 0) { /* First load segment */
1421 obj->vaddrbase = trunc_page(ph->p_vaddr);
1422 obj->mapbase = obj->vaddrbase + obj->relocbase;
1423 } else { /* Last load segment */
1424 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1431 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1436 obj->tlssize = ph->p_memsz;
1437 obj->tlsalign = ph->p_align;
1438 obj->tlsinitsize = ph->p_filesz;
1439 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1443 obj->stack_flags = ph->p_flags;
1447 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1448 obj->relro_size = round_page(ph->p_memsz);
1452 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1453 note_end = note_start + ph->p_filesz;
1454 digest_notes(obj, note_start, note_end);
1459 _rtld_error("%s: too few PT_LOAD segments", path);
1468 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1470 const Elf_Note *note;
1471 const char *note_name;
1474 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1475 note = (const Elf_Note *)((const char *)(note + 1) +
1476 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1477 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1478 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1479 note->n_descsz != sizeof(int32_t))
1481 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1482 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1483 note->n_type != NT_FREEBSD_NOINIT_TAG)
1485 note_name = (const char *)(note + 1);
1486 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1487 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1489 switch (note->n_type) {
1490 case NT_FREEBSD_ABI_TAG:
1491 /* FreeBSD osrel note */
1492 p = (uintptr_t)(note + 1);
1493 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1494 obj->osrel = *(const int32_t *)(p);
1495 dbg("note osrel %d", obj->osrel);
1497 case NT_FREEBSD_FEATURE_CTL:
1498 /* FreeBSD ABI feature control note */
1499 p = (uintptr_t)(note + 1);
1500 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1501 obj->fctl0 = *(const uint32_t *)(p);
1502 dbg("note fctl0 %#x", obj->fctl0);
1504 case NT_FREEBSD_NOINIT_TAG:
1505 /* FreeBSD 'crt does not call init' note */
1506 obj->crt_no_init = true;
1507 dbg("note crt_no_init");
1514 dlcheck(void *handle)
1518 TAILQ_FOREACH(obj, &obj_list, next) {
1519 if (obj == (Obj_Entry *) handle)
1523 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1524 _rtld_error("Invalid shared object handle %p", handle);
1531 * If the given object is already in the donelist, return true. Otherwise
1532 * add the object to the list and return false.
1535 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1539 for (i = 0; i < dlp->num_used; i++)
1540 if (dlp->objs[i] == obj)
1543 * Our donelist allocation should always be sufficient. But if
1544 * our threads locking isn't working properly, more shared objects
1545 * could have been loaded since we allocated the list. That should
1546 * never happen, but we'll handle it properly just in case it does.
1548 if (dlp->num_used < dlp->num_alloc)
1549 dlp->objs[dlp->num_used++] = obj;
1554 * Hash function for symbol table lookup. Don't even think about changing
1555 * this. It is specified by the System V ABI.
1558 elf_hash(const char *name)
1560 const unsigned char *p = (const unsigned char *) name;
1561 unsigned long h = 0;
1564 while (*p != '\0') {
1565 h = (h << 4) + *p++;
1566 if ((g = h & 0xf0000000) != 0)
1574 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1575 * unsigned in case it's implemented with a wider type.
1578 gnu_hash(const char *s)
1584 for (c = *s; c != '\0'; c = *++s)
1586 return (h & 0xffffffff);
1591 * Find the library with the given name, and return its full pathname.
1592 * The returned string is dynamically allocated. Generates an error
1593 * message and returns NULL if the library cannot be found.
1595 * If the second argument is non-NULL, then it refers to an already-
1596 * loaded shared object, whose library search path will be searched.
1598 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1599 * descriptor (which is close-on-exec) will be passed out via the third
1602 * The search order is:
1603 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1604 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1606 * DT_RUNPATH in the referencing file
1607 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1609 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1611 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1614 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1616 char *pathname, *refobj_path;
1618 bool nodeflib, objgiven;
1620 objgiven = refobj != NULL;
1622 if (libmap_disable || !objgiven ||
1623 (name = lm_find(refobj->path, xname)) == NULL)
1626 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1627 if (name[0] != '/' && !trust) {
1628 _rtld_error("Absolute pathname required "
1629 "for shared object \"%s\"", name);
1632 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1633 __DECONST(char *, name)));
1636 dbg(" Searching for \"%s\"", name);
1637 refobj_path = objgiven ? refobj->path : NULL;
1640 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1641 * back to pre-conforming behaviour if user requested so with
1642 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1645 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1646 pathname = search_library_path(name, ld_library_path,
1648 if (pathname != NULL)
1650 if (refobj != NULL) {
1651 pathname = search_library_path(name, refobj->rpath,
1653 if (pathname != NULL)
1656 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1657 if (pathname != NULL)
1659 pathname = search_library_path(name, gethints(false),
1661 if (pathname != NULL)
1663 pathname = search_library_path(name, ld_standard_library_path,
1665 if (pathname != NULL)
1668 nodeflib = objgiven ? refobj->z_nodeflib : false;
1670 pathname = search_library_path(name, refobj->rpath,
1672 if (pathname != NULL)
1675 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1676 pathname = search_library_path(name, obj_main->rpath,
1678 if (pathname != NULL)
1681 pathname = search_library_path(name, ld_library_path,
1683 if (pathname != NULL)
1686 pathname = search_library_path(name, refobj->runpath,
1688 if (pathname != NULL)
1691 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1692 if (pathname != NULL)
1694 pathname = search_library_path(name, gethints(nodeflib),
1696 if (pathname != NULL)
1698 if (objgiven && !nodeflib) {
1699 pathname = search_library_path(name,
1700 ld_standard_library_path, refobj_path, fdp);
1701 if (pathname != NULL)
1706 if (objgiven && refobj->path != NULL) {
1707 _rtld_error("Shared object \"%s\" not found, "
1708 "required by \"%s\"", name, basename(refobj->path));
1710 _rtld_error("Shared object \"%s\" not found", name);
1716 * Given a symbol number in a referencing object, find the corresponding
1717 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1718 * no definition was found. Returns a pointer to the Obj_Entry of the
1719 * defining object via the reference parameter DEFOBJ_OUT.
1722 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1723 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1724 RtldLockState *lockstate)
1728 const Obj_Entry *defobj;
1729 const Ver_Entry *ve;
1735 * If we have already found this symbol, get the information from
1738 if (symnum >= refobj->dynsymcount)
1739 return NULL; /* Bad object */
1740 if (cache != NULL && cache[symnum].sym != NULL) {
1741 *defobj_out = cache[symnum].obj;
1742 return cache[symnum].sym;
1745 ref = refobj->symtab + symnum;
1746 name = refobj->strtab + ref->st_name;
1752 * We don't have to do a full scale lookup if the symbol is local.
1753 * We know it will bind to the instance in this load module; to
1754 * which we already have a pointer (ie ref). By not doing a lookup,
1755 * we not only improve performance, but it also avoids unresolvable
1756 * symbols when local symbols are not in the hash table. This has
1757 * been seen with the ia64 toolchain.
1759 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1760 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1761 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1764 symlook_init(&req, name);
1766 ve = req.ventry = fetch_ventry(refobj, symnum);
1767 req.lockstate = lockstate;
1768 res = symlook_default(&req, refobj);
1771 defobj = req.defobj_out;
1779 * If we found no definition and the reference is weak, treat the
1780 * symbol as having the value zero.
1782 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1788 *defobj_out = defobj;
1789 /* Record the information in the cache to avoid subsequent lookups. */
1790 if (cache != NULL) {
1791 cache[symnum].sym = def;
1792 cache[symnum].obj = defobj;
1795 if (refobj != &obj_rtld)
1796 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1797 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1803 * Return the search path from the ldconfig hints file, reading it if
1804 * necessary. If nostdlib is true, then the default search paths are
1805 * not added to result.
1807 * Returns NULL if there are problems with the hints file,
1808 * or if the search path there is empty.
1811 gethints(bool nostdlib)
1813 static char *filtered_path;
1814 static const char *hints;
1815 static struct elfhints_hdr hdr;
1816 struct fill_search_info_args sargs, hargs;
1817 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1818 struct dl_serpath *SLPpath, *hintpath;
1820 struct stat hint_stat;
1821 unsigned int SLPndx, hintndx, fndx, fcount;
1827 /* First call, read the hints file */
1828 if (hints == NULL) {
1829 /* Keep from trying again in case the hints file is bad. */
1832 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1836 * Check of hdr.dirlistlen value against type limit
1837 * intends to pacify static analyzers. Further
1838 * paranoia leads to checks that dirlist is fully
1839 * contained in the file range.
1841 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1842 hdr.magic != ELFHINTS_MAGIC ||
1843 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1844 fstat(fd, &hint_stat) == -1) {
1851 if (dl + hdr.dirlist < dl)
1854 if (dl + hdr.dirlistlen < dl)
1856 dl += hdr.dirlistlen;
1857 if (dl > hint_stat.st_size)
1859 p = xmalloc(hdr.dirlistlen + 1);
1860 if (pread(fd, p, hdr.dirlistlen + 1,
1861 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1862 p[hdr.dirlistlen] != '\0') {
1871 * If caller agreed to receive list which includes the default
1872 * paths, we are done. Otherwise, if we still did not
1873 * calculated filtered result, do it now.
1876 return (hints[0] != '\0' ? hints : NULL);
1877 if (filtered_path != NULL)
1881 * Obtain the list of all configured search paths, and the
1882 * list of the default paths.
1884 * First estimate the size of the results.
1886 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1888 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1891 sargs.request = RTLD_DI_SERINFOSIZE;
1892 sargs.serinfo = &smeta;
1893 hargs.request = RTLD_DI_SERINFOSIZE;
1894 hargs.serinfo = &hmeta;
1896 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1898 path_enumerate(hints, fill_search_info, NULL, &hargs);
1900 SLPinfo = xmalloc(smeta.dls_size);
1901 hintinfo = xmalloc(hmeta.dls_size);
1904 * Next fetch both sets of paths.
1906 sargs.request = RTLD_DI_SERINFO;
1907 sargs.serinfo = SLPinfo;
1908 sargs.serpath = &SLPinfo->dls_serpath[0];
1909 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1911 hargs.request = RTLD_DI_SERINFO;
1912 hargs.serinfo = hintinfo;
1913 hargs.serpath = &hintinfo->dls_serpath[0];
1914 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1916 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1918 path_enumerate(hints, fill_search_info, NULL, &hargs);
1921 * Now calculate the difference between two sets, by excluding
1922 * standard paths from the full set.
1926 filtered_path = xmalloc(hdr.dirlistlen + 1);
1927 hintpath = &hintinfo->dls_serpath[0];
1928 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1930 SLPpath = &SLPinfo->dls_serpath[0];
1932 * Check each standard path against current.
1934 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1935 /* matched, skip the path */
1936 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1944 * Not matched against any standard path, add the path
1945 * to result. Separate consequtive paths with ':'.
1948 filtered_path[fndx] = ':';
1952 flen = strlen(hintpath->dls_name);
1953 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1956 filtered_path[fndx] = '\0';
1962 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1966 init_dag(Obj_Entry *root)
1968 const Needed_Entry *needed;
1969 const Objlist_Entry *elm;
1972 if (root->dag_inited)
1974 donelist_init(&donelist);
1976 /* Root object belongs to own DAG. */
1977 objlist_push_tail(&root->dldags, root);
1978 objlist_push_tail(&root->dagmembers, root);
1979 donelist_check(&donelist, root);
1982 * Add dependencies of root object to DAG in breadth order
1983 * by exploiting the fact that each new object get added
1984 * to the tail of the dagmembers list.
1986 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1987 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1988 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1990 objlist_push_tail(&needed->obj->dldags, root);
1991 objlist_push_tail(&root->dagmembers, needed->obj);
1994 root->dag_inited = true;
1998 init_marker(Obj_Entry *marker)
2001 bzero(marker, sizeof(*marker));
2002 marker->marker = true;
2006 globallist_curr(const Obj_Entry *obj)
2013 return (__DECONST(Obj_Entry *, obj));
2014 obj = TAILQ_PREV(obj, obj_entry_q, next);
2019 globallist_next(const Obj_Entry *obj)
2023 obj = TAILQ_NEXT(obj, next);
2027 return (__DECONST(Obj_Entry *, obj));
2031 /* Prevent the object from being unmapped while the bind lock is dropped. */
2033 hold_object(Obj_Entry *obj)
2040 unhold_object(Obj_Entry *obj)
2043 assert(obj->holdcount > 0);
2044 if (--obj->holdcount == 0 && obj->unholdfree)
2045 release_object(obj);
2049 process_z(Obj_Entry *root)
2051 const Objlist_Entry *elm;
2055 * Walk over object DAG and process every dependent object
2056 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2057 * to grow their own DAG.
2059 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2060 * symlook_global() to work.
2062 * For DF_1_NODELETE, the DAG should have its reference upped.
2064 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2068 if (obj->z_nodelete && !obj->ref_nodel) {
2069 dbg("obj %s -z nodelete", obj->path);
2072 obj->ref_nodel = true;
2074 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2075 dbg("obj %s -z global", obj->path);
2076 objlist_push_tail(&list_global, obj);
2082 * Initialize the dynamic linker. The argument is the address at which
2083 * the dynamic linker has been mapped into memory. The primary task of
2084 * this function is to relocate the dynamic linker.
2087 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2089 Obj_Entry objtmp; /* Temporary rtld object */
2090 const Elf_Ehdr *ehdr;
2091 const Elf_Dyn *dyn_rpath;
2092 const Elf_Dyn *dyn_soname;
2093 const Elf_Dyn *dyn_runpath;
2095 #ifdef RTLD_INIT_PAGESIZES_EARLY
2096 /* The page size is required by the dynamic memory allocator. */
2097 init_pagesizes(aux_info);
2101 * Conjure up an Obj_Entry structure for the dynamic linker.
2103 * The "path" member can't be initialized yet because string constants
2104 * cannot yet be accessed. Below we will set it correctly.
2106 memset(&objtmp, 0, sizeof(objtmp));
2109 objtmp.mapbase = mapbase;
2111 objtmp.relocbase = mapbase;
2114 objtmp.dynamic = rtld_dynamic(&objtmp);
2115 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2116 assert(objtmp.needed == NULL);
2117 #if !defined(__mips__)
2118 /* MIPS has a bogus DT_TEXTREL. */
2119 assert(!objtmp.textrel);
2122 * Temporarily put the dynamic linker entry into the object list, so
2123 * that symbols can be found.
2125 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2127 ehdr = (Elf_Ehdr *)mapbase;
2128 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2129 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2131 /* Initialize the object list. */
2132 TAILQ_INIT(&obj_list);
2134 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2135 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2137 #ifndef RTLD_INIT_PAGESIZES_EARLY
2138 /* The page size is required by the dynamic memory allocator. */
2139 init_pagesizes(aux_info);
2142 if (aux_info[AT_OSRELDATE] != NULL)
2143 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2145 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2147 /* Replace the path with a dynamically allocated copy. */
2148 obj_rtld.path = xstrdup(ld_path_rtld);
2150 r_debug.r_brk = r_debug_state;
2151 r_debug.r_state = RT_CONSISTENT;
2155 * Retrieve the array of supported page sizes. The kernel provides the page
2156 * sizes in increasing order.
2159 init_pagesizes(Elf_Auxinfo **aux_info)
2161 static size_t psa[MAXPAGESIZES];
2165 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2167 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2168 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2171 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2174 /* As a fallback, retrieve the base page size. */
2175 size = sizeof(psa[0]);
2176 if (aux_info[AT_PAGESZ] != NULL) {
2177 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2181 mib[1] = HW_PAGESIZE;
2185 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2186 _rtld_error("sysctl for hw.pagesize(s) failed");
2192 npagesizes = size / sizeof(pagesizes[0]);
2193 /* Discard any invalid entries at the end of the array. */
2194 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2199 * Add the init functions from a needed object list (and its recursive
2200 * needed objects) to "list". This is not used directly; it is a helper
2201 * function for initlist_add_objects(). The write lock must be held
2202 * when this function is called.
2205 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2207 /* Recursively process the successor needed objects. */
2208 if (needed->next != NULL)
2209 initlist_add_neededs(needed->next, list);
2211 /* Process the current needed object. */
2212 if (needed->obj != NULL)
2213 initlist_add_objects(needed->obj, needed->obj, list);
2217 * Scan all of the DAGs rooted in the range of objects from "obj" to
2218 * "tail" and add their init functions to "list". This recurses over
2219 * the DAGs and ensure the proper init ordering such that each object's
2220 * needed libraries are initialized before the object itself. At the
2221 * same time, this function adds the objects to the global finalization
2222 * list "list_fini" in the opposite order. The write lock must be
2223 * held when this function is called.
2226 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2230 if (obj->init_scanned || obj->init_done)
2232 obj->init_scanned = true;
2234 /* Recursively process the successor objects. */
2235 nobj = globallist_next(obj);
2236 if (nobj != NULL && obj != tail)
2237 initlist_add_objects(nobj, tail, list);
2239 /* Recursively process the needed objects. */
2240 if (obj->needed != NULL)
2241 initlist_add_neededs(obj->needed, list);
2242 if (obj->needed_filtees != NULL)
2243 initlist_add_neededs(obj->needed_filtees, list);
2244 if (obj->needed_aux_filtees != NULL)
2245 initlist_add_neededs(obj->needed_aux_filtees, list);
2247 /* Add the object to the init list. */
2248 objlist_push_tail(list, obj);
2250 /* Add the object to the global fini list in the reverse order. */
2251 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2252 && !obj->on_fini_list) {
2253 objlist_push_head(&list_fini, obj);
2254 obj->on_fini_list = true;
2259 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2263 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2265 Needed_Entry *needed, *needed1;
2267 for (needed = n; needed != NULL; needed = needed->next) {
2268 if (needed->obj != NULL) {
2269 dlclose_locked(needed->obj, lockstate);
2273 for (needed = n; needed != NULL; needed = needed1) {
2274 needed1 = needed->next;
2280 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2283 free_needed_filtees(obj->needed_filtees, lockstate);
2284 obj->needed_filtees = NULL;
2285 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2286 obj->needed_aux_filtees = NULL;
2287 obj->filtees_loaded = false;
2291 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2292 RtldLockState *lockstate)
2295 for (; needed != NULL; needed = needed->next) {
2296 needed->obj = dlopen_object(AT_FDCWD, obj->strtab + needed->name, -1,
2297 obj, flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2298 RTLD_LOCAL, lockstate);
2303 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2306 lock_restart_for_upgrade(lockstate);
2307 if (!obj->filtees_loaded) {
2308 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2309 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2310 obj->filtees_loaded = true;
2315 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2319 for (; needed != NULL; needed = needed->next) {
2320 obj1 = needed->obj = load_object(AT_FDCWD, obj->strtab + needed->name,
2321 -1, obj, flags & ~RTLD_LO_NOLOAD);
2322 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2329 * Given a shared object, traverse its list of needed objects, and load
2330 * each of them. Returns 0 on success. Generates an error message and
2331 * returns -1 on failure.
2334 load_needed_objects(Obj_Entry *first, int flags)
2338 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2341 if (process_needed(obj, obj->needed, flags) == -1)
2348 load_preload_objects(void)
2350 char *p = ld_preload;
2352 static const char delim[] = " \t:;";
2357 p += strspn(p, delim);
2358 while (*p != '\0') {
2359 size_t len = strcspn(p, delim);
2364 obj = load_object(AT_FDCWD, p, -1, NULL, 0);
2366 return -1; /* XXX - cleanup */
2367 obj->z_interpose = true;
2370 p += strspn(p, delim);
2372 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2377 printable_path(const char *path)
2380 return (path == NULL ? "<unknown>" : path);
2384 * Load a shared object into memory, if it is not already loaded. The
2385 * object may be specified by name or by user-supplied file descriptor
2386 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2389 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2393 load_object(int atfd, const char *name, int fd_u, const Obj_Entry *refobj,
2403 TAILQ_FOREACH(obj, &obj_list, next) {
2404 if (obj->marker || obj->doomed)
2406 if (object_match_name(obj, name))
2410 path = find_library(name, refobj, &fd);
2418 * search_library_pathfds() opens a fresh file descriptor for the
2419 * library, so there is no need to dup().
2421 } else if (fd_u == -1) {
2423 * If we didn't find a match by pathname, or the name is not
2424 * supplied, open the file and check again by device and inode.
2425 * This avoids false mismatches caused by multiple links or ".."
2428 * To avoid a race, we open the file and use fstat() rather than
2431 if ((fd = openat(atfd, path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2432 _rtld_error("Cannot open \"%s\"", path);
2437 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2439 _rtld_error("Cannot dup fd");
2444 if (fstat(fd, &sb) == -1) {
2445 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2450 TAILQ_FOREACH(obj, &obj_list, next) {
2451 if (obj->marker || obj->doomed)
2453 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2456 if (obj != NULL && name != NULL) {
2457 object_add_name(obj, name);
2462 if (flags & RTLD_LO_NOLOAD) {
2468 /* First use of this object, so we must map it in */
2469 obj = do_load_object(fd, name, path, &sb, flags);
2478 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2485 * but first, make sure that environment variables haven't been
2486 * used to circumvent the noexec flag on a filesystem.
2488 if (dangerous_ld_env) {
2489 if (fstatfs(fd, &fs) != 0) {
2490 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2493 if (fs.f_flags & MNT_NOEXEC) {
2494 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2498 dbg("loading \"%s\"", printable_path(path));
2499 obj = map_object(fd, printable_path(path), sbp);
2504 * If DT_SONAME is present in the object, digest_dynamic2 already
2505 * added it to the object names.
2508 object_add_name(obj, name);
2510 digest_dynamic(obj, 0);
2511 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2512 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2513 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2515 dbg("refusing to load non-loadable \"%s\"", obj->path);
2516 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2517 munmap(obj->mapbase, obj->mapsize);
2522 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2523 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2526 linkmap_add(obj); /* for GDB & dlinfo() */
2527 max_stack_flags |= obj->stack_flags;
2529 dbg(" %p .. %p: %s", obj->mapbase,
2530 obj->mapbase + obj->mapsize - 1, obj->path);
2532 dbg(" WARNING: %s has impure text", obj->path);
2533 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2540 obj_from_addr(const void *addr)
2544 TAILQ_FOREACH(obj, &obj_list, next) {
2547 if (addr < (void *) obj->mapbase)
2549 if (addr < (void *)(obj->mapbase + obj->mapsize))
2558 Elf_Addr *preinit_addr;
2561 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2562 if (preinit_addr == NULL)
2565 for (index = 0; index < obj_main->preinit_array_num; index++) {
2566 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2567 dbg("calling preinit function for %s at %p", obj_main->path,
2568 (void *)preinit_addr[index]);
2569 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2570 0, 0, obj_main->path);
2571 call_init_pointer(obj_main, preinit_addr[index]);
2577 * Call the finalization functions for each of the objects in "list"
2578 * belonging to the DAG of "root" and referenced once. If NULL "root"
2579 * is specified, every finalization function will be called regardless
2580 * of the reference count and the list elements won't be freed. All of
2581 * the objects are expected to have non-NULL fini functions.
2584 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2588 Elf_Addr *fini_addr;
2591 assert(root == NULL || root->refcount == 1);
2594 root->doomed = true;
2597 * Preserve the current error message since a fini function might
2598 * call into the dynamic linker and overwrite it.
2600 saved_msg = errmsg_save();
2602 STAILQ_FOREACH(elm, list, link) {
2603 if (root != NULL && (elm->obj->refcount != 1 ||
2604 objlist_find(&root->dagmembers, elm->obj) == NULL))
2606 /* Remove object from fini list to prevent recursive invocation. */
2607 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2608 /* Ensure that new references cannot be acquired. */
2609 elm->obj->doomed = true;
2611 hold_object(elm->obj);
2612 lock_release(rtld_bind_lock, lockstate);
2614 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2615 * When this happens, DT_FINI_ARRAY is processed first.
2617 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2618 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2619 for (index = elm->obj->fini_array_num - 1; index >= 0;
2621 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2622 dbg("calling fini function for %s at %p",
2623 elm->obj->path, (void *)fini_addr[index]);
2624 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2625 (void *)fini_addr[index], 0, 0, elm->obj->path);
2626 call_initfini_pointer(elm->obj, fini_addr[index]);
2630 if (elm->obj->fini != (Elf_Addr)NULL) {
2631 dbg("calling fini function for %s at %p", elm->obj->path,
2632 (void *)elm->obj->fini);
2633 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2634 0, 0, elm->obj->path);
2635 call_initfini_pointer(elm->obj, elm->obj->fini);
2637 wlock_acquire(rtld_bind_lock, lockstate);
2638 unhold_object(elm->obj);
2639 /* No need to free anything if process is going down. */
2643 * We must restart the list traversal after every fini call
2644 * because a dlclose() call from the fini function or from
2645 * another thread might have modified the reference counts.
2649 } while (elm != NULL);
2650 errmsg_restore(saved_msg);
2654 * Call the initialization functions for each of the objects in
2655 * "list". All of the objects are expected to have non-NULL init
2659 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2664 Elf_Addr *init_addr;
2668 * Clean init_scanned flag so that objects can be rechecked and
2669 * possibly initialized earlier if any of vectors called below
2670 * cause the change by using dlopen.
2672 TAILQ_FOREACH(obj, &obj_list, next) {
2675 obj->init_scanned = false;
2679 * Preserve the current error message since an init function might
2680 * call into the dynamic linker and overwrite it.
2682 saved_msg = errmsg_save();
2683 STAILQ_FOREACH(elm, list, link) {
2684 if (elm->obj->init_done) /* Initialized early. */
2687 * Race: other thread might try to use this object before current
2688 * one completes the initialization. Not much can be done here
2689 * without better locking.
2691 elm->obj->init_done = true;
2692 hold_object(elm->obj);
2693 lock_release(rtld_bind_lock, lockstate);
2696 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2697 * When this happens, DT_INIT is processed first.
2699 if (elm->obj->init != (Elf_Addr)NULL) {
2700 dbg("calling init function for %s at %p", elm->obj->path,
2701 (void *)elm->obj->init);
2702 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2703 0, 0, elm->obj->path);
2704 call_initfini_pointer(elm->obj, elm->obj->init);
2706 init_addr = (Elf_Addr *)elm->obj->init_array;
2707 if (init_addr != NULL) {
2708 for (index = 0; index < elm->obj->init_array_num; index++) {
2709 if (init_addr[index] != 0 && init_addr[index] != 1) {
2710 dbg("calling init function for %s at %p", elm->obj->path,
2711 (void *)init_addr[index]);
2712 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2713 (void *)init_addr[index], 0, 0, elm->obj->path);
2714 call_init_pointer(elm->obj, init_addr[index]);
2718 wlock_acquire(rtld_bind_lock, lockstate);
2719 unhold_object(elm->obj);
2721 errmsg_restore(saved_msg);
2725 objlist_clear(Objlist *list)
2729 while (!STAILQ_EMPTY(list)) {
2730 elm = STAILQ_FIRST(list);
2731 STAILQ_REMOVE_HEAD(list, link);
2736 static Objlist_Entry *
2737 objlist_find(Objlist *list, const Obj_Entry *obj)
2741 STAILQ_FOREACH(elm, list, link)
2742 if (elm->obj == obj)
2748 objlist_init(Objlist *list)
2754 objlist_push_head(Objlist *list, Obj_Entry *obj)
2758 elm = NEW(Objlist_Entry);
2760 STAILQ_INSERT_HEAD(list, elm, link);
2764 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2768 elm = NEW(Objlist_Entry);
2770 STAILQ_INSERT_TAIL(list, elm, link);
2774 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2776 Objlist_Entry *elm, *listelm;
2778 STAILQ_FOREACH(listelm, list, link) {
2779 if (listelm->obj == listobj)
2782 elm = NEW(Objlist_Entry);
2784 if (listelm != NULL)
2785 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2787 STAILQ_INSERT_TAIL(list, elm, link);
2791 objlist_remove(Objlist *list, Obj_Entry *obj)
2795 if ((elm = objlist_find(list, obj)) != NULL) {
2796 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2802 * Relocate dag rooted in the specified object.
2803 * Returns 0 on success, or -1 on failure.
2807 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2808 int flags, RtldLockState *lockstate)
2814 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2815 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2824 * Prepare for, or clean after, relocating an object marked with
2825 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2826 * segments are remapped read-write. After relocations are done, the
2827 * segment's permissions are returned back to the modes specified in
2828 * the phdrs. If any relocation happened, or always for wired
2829 * program, COW is triggered.
2832 reloc_textrel_prot(Obj_Entry *obj, bool before)
2839 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2841 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2843 base = obj->relocbase + trunc_page(ph->p_vaddr);
2844 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2845 trunc_page(ph->p_vaddr);
2846 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2847 if (mprotect(base, sz, prot) == -1) {
2848 _rtld_error("%s: Cannot write-%sable text segment: %s",
2849 obj->path, before ? "en" : "dis",
2850 rtld_strerror(errno));
2858 * Relocate single object.
2859 * Returns 0 on success, or -1 on failure.
2862 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2863 int flags, RtldLockState *lockstate)
2868 obj->relocated = true;
2870 dbg("relocating \"%s\"", obj->path);
2872 if (obj->symtab == NULL || obj->strtab == NULL ||
2873 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2874 _rtld_error("%s: Shared object has no run-time symbol table",
2879 /* There are relocations to the write-protected text segment. */
2880 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2883 /* Process the non-PLT non-IFUNC relocations. */
2884 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2887 /* Re-protected the text segment. */
2888 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2891 /* Set the special PLT or GOT entries. */
2894 /* Process the PLT relocations. */
2895 if (reloc_plt(obj, flags, lockstate) == -1)
2897 /* Relocate the jump slots if we are doing immediate binding. */
2898 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
2903 * Process the non-PLT IFUNC relocations. The relocations are
2904 * processed in two phases, because IFUNC resolvers may
2905 * reference other symbols, which must be readily processed
2906 * before resolvers are called.
2908 if (obj->non_plt_gnu_ifunc &&
2909 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2912 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2916 * Set up the magic number and version in the Obj_Entry. These
2917 * were checked in the crt1.o from the original ElfKit, so we
2918 * set them for backward compatibility.
2920 obj->magic = RTLD_MAGIC;
2921 obj->version = RTLD_VERSION;
2927 * Relocate newly-loaded shared objects. The argument is a pointer to
2928 * the Obj_Entry for the first such object. All objects from the first
2929 * to the end of the list of objects are relocated. Returns 0 on success,
2933 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2934 int flags, RtldLockState *lockstate)
2939 for (error = 0, obj = first; obj != NULL;
2940 obj = TAILQ_NEXT(obj, next)) {
2943 error = relocate_object(obj, bind_now, rtldobj, flags,
2952 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2953 * referencing STT_GNU_IFUNC symbols is postponed till the other
2954 * relocations are done. The indirect functions specified as
2955 * ifunc are allowed to call other symbols, so we need to have
2956 * objects relocated before asking for resolution from indirects.
2958 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2959 * instead of the usual lazy handling of PLT slots. It is
2960 * consistent with how GNU does it.
2963 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2964 RtldLockState *lockstate)
2967 if (obj->ifuncs_resolved)
2969 obj->ifuncs_resolved = true;
2970 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2972 if ((obj->bind_now || bind_now) && obj->gnu_ifunc) {
2973 if (obj_disable_relro(obj) ||
2974 reloc_gnu_ifunc(obj, flags, lockstate) == -1 ||
2975 obj_enforce_relro(obj))
2982 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2983 RtldLockState *lockstate)
2988 STAILQ_FOREACH(elm, list, link) {
2992 if (resolve_object_ifunc(obj, bind_now, flags,
3000 * Cleanup procedure. It will be called (by the atexit mechanism) just
3001 * before the process exits.
3006 RtldLockState lockstate;
3008 wlock_acquire(rtld_bind_lock, &lockstate);
3010 objlist_call_fini(&list_fini, NULL, &lockstate);
3011 /* No need to remove the items from the list, since we are exiting. */
3012 if (!libmap_disable)
3014 lock_release(rtld_bind_lock, &lockstate);
3018 * Iterate over a search path, translate each element, and invoke the
3019 * callback on the result.
3022 path_enumerate(const char *path, path_enum_proc callback,
3023 const char *refobj_path, void *arg)
3029 path += strspn(path, ":;");
3030 while (*path != '\0') {
3034 len = strcspn(path, ":;");
3035 trans = lm_findn(refobj_path, path, len);
3037 res = callback(trans, strlen(trans), arg);
3039 res = callback(path, len, arg);
3045 path += strspn(path, ":;");
3051 struct try_library_args {
3060 try_library_path(const char *dir, size_t dirlen, void *param)
3062 struct try_library_args *arg;
3066 if (*dir == '/' || trust) {
3069 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3072 pathname = arg->buffer;
3073 strncpy(pathname, dir, dirlen);
3074 pathname[dirlen] = '/';
3075 strcpy(pathname + dirlen + 1, arg->name);
3077 dbg(" Trying \"%s\"", pathname);
3078 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3080 dbg(" Opened \"%s\", fd %d", pathname, fd);
3081 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3082 strcpy(pathname, arg->buffer);
3086 dbg(" Failed to open \"%s\": %s",
3087 pathname, rtld_strerror(errno));
3094 search_library_path(const char *name, const char *path,
3095 const char *refobj_path, int *fdp)
3098 struct try_library_args arg;
3104 arg.namelen = strlen(name);
3105 arg.buffer = xmalloc(PATH_MAX);
3106 arg.buflen = PATH_MAX;
3109 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3119 * Finds the library with the given name using the directory descriptors
3120 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3122 * Returns a freshly-opened close-on-exec file descriptor for the library,
3123 * or -1 if the library cannot be found.
3126 search_library_pathfds(const char *name, const char *path, int *fdp)
3128 char *envcopy, *fdstr, *found, *last_token;
3132 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3134 /* Don't load from user-specified libdirs into setuid binaries. */
3138 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3142 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3143 if (name[0] == '/') {
3144 dbg("Absolute path (%s) passed to %s", name, __func__);
3149 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3150 * copy of the path, as strtok_r rewrites separator tokens
3154 envcopy = xstrdup(path);
3155 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3156 fdstr = strtok_r(NULL, ":", &last_token)) {
3157 dirfd = parse_integer(fdstr);
3159 _rtld_error("failed to parse directory FD: '%s'",
3163 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3166 len = strlen(fdstr) + strlen(name) + 3;
3167 found = xmalloc(len);
3168 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3169 _rtld_error("error generating '%d/%s'",
3173 dbg("open('%s') => %d", found, fd);
3184 dlclose(void *handle)
3186 RtldLockState lockstate;
3189 wlock_acquire(rtld_bind_lock, &lockstate);
3190 error = dlclose_locked(handle, &lockstate);
3191 lock_release(rtld_bind_lock, &lockstate);
3196 dlclose_locked(void *handle, RtldLockState *lockstate)
3200 root = dlcheck(handle);
3203 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3206 /* Unreference the object and its dependencies. */
3207 root->dl_refcount--;
3209 if (root->refcount == 1) {
3211 * The object will be no longer referenced, so we must unload it.
3212 * First, call the fini functions.
3214 objlist_call_fini(&list_fini, root, lockstate);
3218 /* Finish cleaning up the newly-unreferenced objects. */
3219 GDB_STATE(RT_DELETE,&root->linkmap);
3220 unload_object(root, lockstate);
3221 GDB_STATE(RT_CONSISTENT,NULL);
3225 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3232 char *msg = error_message;
3233 error_message = NULL;
3238 * This function is deprecated and has no effect.
3241 dllockinit(void *context,
3242 void *(*_lock_create)(void *context) __unused,
3243 void (*_rlock_acquire)(void *lock) __unused,
3244 void (*_wlock_acquire)(void *lock) __unused,
3245 void (*_lock_release)(void *lock) __unused,
3246 void (*_lock_destroy)(void *lock) __unused,
3247 void (*context_destroy)(void *context))
3249 static void *cur_context;
3250 static void (*cur_context_destroy)(void *);
3252 /* Just destroy the context from the previous call, if necessary. */
3253 if (cur_context_destroy != NULL)
3254 cur_context_destroy(cur_context);
3255 cur_context = context;
3256 cur_context_destroy = context_destroy;
3260 dlopenat(int fd, const char *name, int mode)
3263 return (rtld_dlopen(fd, name, -1, mode));
3267 dlopen(const char *name, int mode)
3270 return (rtld_dlopen(AT_FDCWD, name, -1, mode));
3274 fdlopen(int fd, int mode)
3277 return (rtld_dlopen(AT_FDCWD, NULL, fd, mode));
3281 rtld_dlopen(int atfd, const char *name, int fd, int mode)
3283 RtldLockState lockstate;
3286 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3287 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3288 if (ld_tracing != NULL) {
3289 rlock_acquire(rtld_bind_lock, &lockstate);
3290 if (sigsetjmp(lockstate.env, 0) != 0)
3291 lock_upgrade(rtld_bind_lock, &lockstate);
3292 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3293 lock_release(rtld_bind_lock, &lockstate);
3295 lo_flags = RTLD_LO_DLOPEN;
3296 if (mode & RTLD_NODELETE)
3297 lo_flags |= RTLD_LO_NODELETE;
3298 if (mode & RTLD_NOLOAD)
3299 lo_flags |= RTLD_LO_NOLOAD;
3300 if (ld_tracing != NULL)
3301 lo_flags |= RTLD_LO_TRACE;
3303 return (dlopen_object(atfd, name, fd, obj_main, lo_flags,
3304 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3308 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3313 if (obj->refcount == 0)
3314 unload_object(obj, lockstate);
3318 dlopen_object(int atfd, const char *name, int fd, Obj_Entry *refobj,
3319 int lo_flags, int mode, RtldLockState *lockstate)
3321 Obj_Entry *old_obj_tail;
3324 RtldLockState mlockstate;
3327 objlist_init(&initlist);
3329 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3330 wlock_acquire(rtld_bind_lock, &mlockstate);
3331 lockstate = &mlockstate;
3333 GDB_STATE(RT_ADD,NULL);
3335 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3337 if (name == NULL && fd == -1) {
3341 obj = load_object(atfd, name, fd, refobj, lo_flags);
3346 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3347 objlist_push_tail(&list_global, obj);
3348 if (globallist_next(old_obj_tail) != NULL) {
3349 /* We loaded something new. */
3350 assert(globallist_next(old_obj_tail) == obj);
3351 result = load_needed_objects(obj,
3352 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3356 result = rtld_verify_versions(&obj->dagmembers);
3357 if (result != -1 && ld_tracing)
3359 if (result == -1 || relocate_object_dag(obj,
3360 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3361 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3363 dlopen_cleanup(obj, lockstate);
3365 } else if (lo_flags & RTLD_LO_EARLY) {
3367 * Do not call the init functions for early loaded
3368 * filtees. The image is still not initialized enough
3371 * Our object is found by the global object list and
3372 * will be ordered among all init calls done right
3373 * before transferring control to main.
3376 /* Make list of init functions to call. */
3377 initlist_add_objects(obj, obj, &initlist);
3380 * Process all no_delete or global objects here, given
3381 * them own DAGs to prevent their dependencies from being
3382 * unloaded. This has to be done after we have loaded all
3383 * of the dependencies, so that we do not miss any.
3389 * Bump the reference counts for objects on this DAG. If
3390 * this is the first dlopen() call for the object that was
3391 * already loaded as a dependency, initialize the dag
3397 if ((lo_flags & RTLD_LO_TRACE) != 0)
3400 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3401 obj->z_nodelete) && !obj->ref_nodel) {
3402 dbg("obj %s nodelete", obj->path);
3404 obj->z_nodelete = obj->ref_nodel = true;
3408 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3410 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3412 if (!(lo_flags & RTLD_LO_EARLY)) {
3413 map_stacks_exec(lockstate);
3416 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3417 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3419 objlist_clear(&initlist);
3420 dlopen_cleanup(obj, lockstate);
3421 if (lockstate == &mlockstate)
3422 lock_release(rtld_bind_lock, lockstate);
3426 if (!(lo_flags & RTLD_LO_EARLY)) {
3427 /* Call the init functions. */
3428 objlist_call_init(&initlist, lockstate);
3430 objlist_clear(&initlist);
3431 if (lockstate == &mlockstate)
3432 lock_release(rtld_bind_lock, lockstate);
3435 trace_loaded_objects(obj);
3436 if (lockstate == &mlockstate)
3437 lock_release(rtld_bind_lock, lockstate);
3442 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3446 const Obj_Entry *obj, *defobj;
3449 RtldLockState lockstate;
3456 symlook_init(&req, name);
3458 req.flags = flags | SYMLOOK_IN_PLT;
3459 req.lockstate = &lockstate;
3461 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3462 rlock_acquire(rtld_bind_lock, &lockstate);
3463 if (sigsetjmp(lockstate.env, 0) != 0)
3464 lock_upgrade(rtld_bind_lock, &lockstate);
3465 if (handle == NULL || handle == RTLD_NEXT ||
3466 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3468 if ((obj = obj_from_addr(retaddr)) == NULL) {
3469 _rtld_error("Cannot determine caller's shared object");
3470 lock_release(rtld_bind_lock, &lockstate);
3471 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3474 if (handle == NULL) { /* Just the caller's shared object. */
3475 res = symlook_obj(&req, obj);
3478 defobj = req.defobj_out;
3480 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3481 handle == RTLD_SELF) { /* ... caller included */
3482 if (handle == RTLD_NEXT)
3483 obj = globallist_next(obj);
3484 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3487 res = symlook_obj(&req, obj);
3490 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3492 defobj = req.defobj_out;
3493 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3499 * Search the dynamic linker itself, and possibly resolve the
3500 * symbol from there. This is how the application links to
3501 * dynamic linker services such as dlopen.
3503 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3504 res = symlook_obj(&req, &obj_rtld);
3507 defobj = req.defobj_out;
3511 assert(handle == RTLD_DEFAULT);
3512 res = symlook_default(&req, obj);
3514 defobj = req.defobj_out;
3519 if ((obj = dlcheck(handle)) == NULL) {
3520 lock_release(rtld_bind_lock, &lockstate);
3521 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3525 donelist_init(&donelist);
3526 if (obj->mainprog) {
3527 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3528 res = symlook_global(&req, &donelist);
3531 defobj = req.defobj_out;
3534 * Search the dynamic linker itself, and possibly resolve the
3535 * symbol from there. This is how the application links to
3536 * dynamic linker services such as dlopen.
3538 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3539 res = symlook_obj(&req, &obj_rtld);
3542 defobj = req.defobj_out;
3547 /* Search the whole DAG rooted at the given object. */
3548 res = symlook_list(&req, &obj->dagmembers, &donelist);
3551 defobj = req.defobj_out;
3557 lock_release(rtld_bind_lock, &lockstate);
3560 * The value required by the caller is derived from the value
3561 * of the symbol. this is simply the relocated value of the
3564 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3565 sym = make_function_pointer(def, defobj);
3566 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3567 sym = rtld_resolve_ifunc(defobj, def);
3568 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3569 ti.ti_module = defobj->tlsindex;
3570 ti.ti_offset = def->st_value;
3571 sym = __tls_get_addr(&ti);
3573 sym = defobj->relocbase + def->st_value;
3574 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3578 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3579 ve != NULL ? ve->name : "");
3580 lock_release(rtld_bind_lock, &lockstate);
3581 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3586 dlsym(void *handle, const char *name)
3588 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3593 dlfunc(void *handle, const char *name)
3600 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3606 dlvsym(void *handle, const char *name, const char *version)
3610 ventry.name = version;
3612 ventry.hash = elf_hash(version);
3614 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3619 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3621 const Obj_Entry *obj;
3622 RtldLockState lockstate;
3624 rlock_acquire(rtld_bind_lock, &lockstate);
3625 obj = obj_from_addr(addr);
3627 _rtld_error("No shared object contains address");
3628 lock_release(rtld_bind_lock, &lockstate);
3631 rtld_fill_dl_phdr_info(obj, phdr_info);
3632 lock_release(rtld_bind_lock, &lockstate);
3637 dladdr(const void *addr, Dl_info *info)
3639 const Obj_Entry *obj;
3642 unsigned long symoffset;
3643 RtldLockState lockstate;
3645 rlock_acquire(rtld_bind_lock, &lockstate);
3646 obj = obj_from_addr(addr);
3648 _rtld_error("No shared object contains address");
3649 lock_release(rtld_bind_lock, &lockstate);
3652 info->dli_fname = obj->path;
3653 info->dli_fbase = obj->mapbase;
3654 info->dli_saddr = (void *)0;
3655 info->dli_sname = NULL;
3658 * Walk the symbol list looking for the symbol whose address is
3659 * closest to the address sent in.
3661 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3662 def = obj->symtab + symoffset;
3665 * For skip the symbol if st_shndx is either SHN_UNDEF or
3668 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3672 * If the symbol is greater than the specified address, or if it
3673 * is further away from addr than the current nearest symbol,
3676 symbol_addr = obj->relocbase + def->st_value;
3677 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3680 /* Update our idea of the nearest symbol. */
3681 info->dli_sname = obj->strtab + def->st_name;
3682 info->dli_saddr = symbol_addr;
3685 if (info->dli_saddr == addr)
3688 lock_release(rtld_bind_lock, &lockstate);
3693 dlinfo(void *handle, int request, void *p)
3695 const Obj_Entry *obj;
3696 RtldLockState lockstate;
3699 rlock_acquire(rtld_bind_lock, &lockstate);
3701 if (handle == NULL || handle == RTLD_SELF) {
3704 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3705 if ((obj = obj_from_addr(retaddr)) == NULL)
3706 _rtld_error("Cannot determine caller's shared object");
3708 obj = dlcheck(handle);
3711 lock_release(rtld_bind_lock, &lockstate);
3717 case RTLD_DI_LINKMAP:
3718 *((struct link_map const **)p) = &obj->linkmap;
3720 case RTLD_DI_ORIGIN:
3721 error = rtld_dirname(obj->path, p);
3724 case RTLD_DI_SERINFOSIZE:
3725 case RTLD_DI_SERINFO:
3726 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3730 _rtld_error("Invalid request %d passed to dlinfo()", request);
3734 lock_release(rtld_bind_lock, &lockstate);
3740 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3743 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3744 phdr_info->dlpi_name = obj->path;
3745 phdr_info->dlpi_phdr = obj->phdr;
3746 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3747 phdr_info->dlpi_tls_modid = obj->tlsindex;
3748 phdr_info->dlpi_tls_data = obj->tlsinit;
3749 phdr_info->dlpi_adds = obj_loads;
3750 phdr_info->dlpi_subs = obj_loads - obj_count;
3754 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3756 struct dl_phdr_info phdr_info;
3757 Obj_Entry *obj, marker;
3758 RtldLockState bind_lockstate, phdr_lockstate;
3761 init_marker(&marker);
3764 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3765 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3766 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3767 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3768 rtld_fill_dl_phdr_info(obj, &phdr_info);
3770 lock_release(rtld_bind_lock, &bind_lockstate);
3772 error = callback(&phdr_info, sizeof phdr_info, param);
3774 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3776 obj = globallist_next(&marker);
3777 TAILQ_REMOVE(&obj_list, &marker, next);
3779 lock_release(rtld_bind_lock, &bind_lockstate);
3780 lock_release(rtld_phdr_lock, &phdr_lockstate);
3786 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3787 lock_release(rtld_bind_lock, &bind_lockstate);
3788 error = callback(&phdr_info, sizeof(phdr_info), param);
3790 lock_release(rtld_phdr_lock, &phdr_lockstate);
3795 fill_search_info(const char *dir, size_t dirlen, void *param)
3797 struct fill_search_info_args *arg;
3801 if (arg->request == RTLD_DI_SERINFOSIZE) {
3802 arg->serinfo->dls_cnt ++;
3803 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3805 struct dl_serpath *s_entry;
3807 s_entry = arg->serpath;
3808 s_entry->dls_name = arg->strspace;
3809 s_entry->dls_flags = arg->flags;
3811 strncpy(arg->strspace, dir, dirlen);
3812 arg->strspace[dirlen] = '\0';
3814 arg->strspace += dirlen + 1;
3822 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3824 struct dl_serinfo _info;
3825 struct fill_search_info_args args;
3827 args.request = RTLD_DI_SERINFOSIZE;
3828 args.serinfo = &_info;
3830 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3833 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3834 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3835 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3836 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3837 if (!obj->z_nodeflib)
3838 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3841 if (request == RTLD_DI_SERINFOSIZE) {
3842 info->dls_size = _info.dls_size;
3843 info->dls_cnt = _info.dls_cnt;
3847 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3848 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3852 args.request = RTLD_DI_SERINFO;
3853 args.serinfo = info;
3854 args.serpath = &info->dls_serpath[0];
3855 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3857 args.flags = LA_SER_RUNPATH;
3858 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
3861 args.flags = LA_SER_LIBPATH;
3862 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
3865 args.flags = LA_SER_RUNPATH;
3866 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
3869 args.flags = LA_SER_CONFIG;
3870 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
3874 args.flags = LA_SER_DEFAULT;
3875 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
3876 fill_search_info, NULL, &args) != NULL)
3882 rtld_dirname(const char *path, char *bname)
3886 /* Empty or NULL string gets treated as "." */
3887 if (path == NULL || *path == '\0') {
3893 /* Strip trailing slashes */
3894 endp = path + strlen(path) - 1;
3895 while (endp > path && *endp == '/')
3898 /* Find the start of the dir */
3899 while (endp > path && *endp != '/')
3902 /* Either the dir is "/" or there are no slashes */
3904 bname[0] = *endp == '/' ? '/' : '.';
3910 } while (endp > path && *endp == '/');
3913 if (endp - path + 2 > PATH_MAX)
3915 _rtld_error("Filename is too long: %s", path);
3919 strncpy(bname, path, endp - path + 1);
3920 bname[endp - path + 1] = '\0';
3925 rtld_dirname_abs(const char *path, char *base)
3929 if (realpath(path, base) == NULL)
3931 dbg("%s -> %s", path, base);
3932 last = strrchr(base, '/');
3941 linkmap_add(Obj_Entry *obj)
3943 struct link_map *l = &obj->linkmap;
3944 struct link_map *prev;
3946 obj->linkmap.l_name = obj->path;
3947 obj->linkmap.l_addr = obj->mapbase;
3948 obj->linkmap.l_ld = obj->dynamic;
3950 /* GDB needs load offset on MIPS to use the symbols */
3951 obj->linkmap.l_offs = obj->relocbase;
3954 if (r_debug.r_map == NULL) {
3960 * Scan to the end of the list, but not past the entry for the
3961 * dynamic linker, which we want to keep at the very end.
3963 for (prev = r_debug.r_map;
3964 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3965 prev = prev->l_next)
3968 /* Link in the new entry. */
3970 l->l_next = prev->l_next;
3971 if (l->l_next != NULL)
3972 l->l_next->l_prev = l;
3977 linkmap_delete(Obj_Entry *obj)
3979 struct link_map *l = &obj->linkmap;
3981 if (l->l_prev == NULL) {
3982 if ((r_debug.r_map = l->l_next) != NULL)
3983 l->l_next->l_prev = NULL;
3987 if ((l->l_prev->l_next = l->l_next) != NULL)
3988 l->l_next->l_prev = l->l_prev;
3992 * Function for the debugger to set a breakpoint on to gain control.
3994 * The two parameters allow the debugger to easily find and determine
3995 * what the runtime loader is doing and to whom it is doing it.
3997 * When the loadhook trap is hit (r_debug_state, set at program
3998 * initialization), the arguments can be found on the stack:
4000 * +8 struct link_map *m
4001 * +4 struct r_debug *rd
4005 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4008 * The following is a hack to force the compiler to emit calls to
4009 * this function, even when optimizing. If the function is empty,
4010 * the compiler is not obliged to emit any code for calls to it,
4011 * even when marked __noinline. However, gdb depends on those
4014 __compiler_membar();
4018 * A function called after init routines have completed. This can be used to
4019 * break before a program's entry routine is called, and can be used when
4020 * main is not available in the symbol table.
4023 _r_debug_postinit(struct link_map *m __unused)
4026 /* See r_debug_state(). */
4027 __compiler_membar();
4031 release_object(Obj_Entry *obj)
4034 if (obj->holdcount > 0) {
4035 obj->unholdfree = true;
4038 munmap(obj->mapbase, obj->mapsize);
4039 linkmap_delete(obj);
4044 * Get address of the pointer variable in the main program.
4045 * Prefer non-weak symbol over the weak one.
4047 static const void **
4048 get_program_var_addr(const char *name, RtldLockState *lockstate)
4053 symlook_init(&req, name);
4054 req.lockstate = lockstate;
4055 donelist_init(&donelist);
4056 if (symlook_global(&req, &donelist) != 0)
4058 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4059 return ((const void **)make_function_pointer(req.sym_out,
4061 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4062 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4064 return ((const void **)(req.defobj_out->relocbase +
4065 req.sym_out->st_value));
4069 * Set a pointer variable in the main program to the given value. This
4070 * is used to set key variables such as "environ" before any of the
4071 * init functions are called.
4074 set_program_var(const char *name, const void *value)
4078 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4079 dbg("\"%s\": *%p <-- %p", name, addr, value);
4085 * Search the global objects, including dependencies and main object,
4086 * for the given symbol.
4089 symlook_global(SymLook *req, DoneList *donelist)
4092 const Objlist_Entry *elm;
4095 symlook_init_from_req(&req1, req);
4097 /* Search all objects loaded at program start up. */
4098 if (req->defobj_out == NULL ||
4099 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4100 res = symlook_list(&req1, &list_main, donelist);
4101 if (res == 0 && (req->defobj_out == NULL ||
4102 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4103 req->sym_out = req1.sym_out;
4104 req->defobj_out = req1.defobj_out;
4105 assert(req->defobj_out != NULL);
4109 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4110 STAILQ_FOREACH(elm, &list_global, link) {
4111 if (req->defobj_out != NULL &&
4112 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4114 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4115 if (res == 0 && (req->defobj_out == NULL ||
4116 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4117 req->sym_out = req1.sym_out;
4118 req->defobj_out = req1.defobj_out;
4119 assert(req->defobj_out != NULL);
4123 return (req->sym_out != NULL ? 0 : ESRCH);
4127 * Given a symbol name in a referencing object, find the corresponding
4128 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4129 * no definition was found. Returns a pointer to the Obj_Entry of the
4130 * defining object via the reference parameter DEFOBJ_OUT.
4133 symlook_default(SymLook *req, const Obj_Entry *refobj)
4136 const Objlist_Entry *elm;
4140 donelist_init(&donelist);
4141 symlook_init_from_req(&req1, req);
4144 * Look first in the referencing object if linked symbolically,
4145 * and similarly handle protected symbols.
4147 res = symlook_obj(&req1, refobj);
4148 if (res == 0 && (refobj->symbolic ||
4149 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4150 req->sym_out = req1.sym_out;
4151 req->defobj_out = req1.defobj_out;
4152 assert(req->defobj_out != NULL);
4154 if (refobj->symbolic || req->defobj_out != NULL)
4155 donelist_check(&donelist, refobj);
4157 symlook_global(req, &donelist);
4159 /* Search all dlopened DAGs containing the referencing object. */
4160 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4161 if (req->sym_out != NULL &&
4162 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4164 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4165 if (res == 0 && (req->sym_out == NULL ||
4166 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4167 req->sym_out = req1.sym_out;
4168 req->defobj_out = req1.defobj_out;
4169 assert(req->defobj_out != NULL);
4174 * Search the dynamic linker itself, and possibly resolve the
4175 * symbol from there. This is how the application links to
4176 * dynamic linker services such as dlopen.
4178 if (req->sym_out == NULL ||
4179 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4180 res = symlook_obj(&req1, &obj_rtld);
4182 req->sym_out = req1.sym_out;
4183 req->defobj_out = req1.defobj_out;
4184 assert(req->defobj_out != NULL);
4188 return (req->sym_out != NULL ? 0 : ESRCH);
4192 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4195 const Obj_Entry *defobj;
4196 const Objlist_Entry *elm;
4202 STAILQ_FOREACH(elm, objlist, link) {
4203 if (donelist_check(dlp, elm->obj))
4205 symlook_init_from_req(&req1, req);
4206 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4207 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4209 defobj = req1.defobj_out;
4210 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4217 req->defobj_out = defobj;
4224 * Search the chain of DAGS cointed to by the given Needed_Entry
4225 * for a symbol of the given name. Each DAG is scanned completely
4226 * before advancing to the next one. Returns a pointer to the symbol,
4227 * or NULL if no definition was found.
4230 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4233 const Needed_Entry *n;
4234 const Obj_Entry *defobj;
4240 symlook_init_from_req(&req1, req);
4241 for (n = needed; n != NULL; n = n->next) {
4242 if (n->obj == NULL ||
4243 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4245 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4247 defobj = req1.defobj_out;
4248 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4254 req->defobj_out = defobj;
4261 * Search the symbol table of a single shared object for a symbol of
4262 * the given name and version, if requested. Returns a pointer to the
4263 * symbol, or NULL if no definition was found. If the object is
4264 * filter, return filtered symbol from filtee.
4266 * The symbol's hash value is passed in for efficiency reasons; that
4267 * eliminates many recomputations of the hash value.
4270 symlook_obj(SymLook *req, const Obj_Entry *obj)
4274 int flags, res, mres;
4277 * If there is at least one valid hash at this point, we prefer to
4278 * use the faster GNU version if available.
4280 if (obj->valid_hash_gnu)
4281 mres = symlook_obj1_gnu(req, obj);
4282 else if (obj->valid_hash_sysv)
4283 mres = symlook_obj1_sysv(req, obj);
4288 if (obj->needed_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_filtees, &donelist);
4295 req->sym_out = req1.sym_out;
4296 req->defobj_out = req1.defobj_out;
4300 if (obj->needed_aux_filtees != NULL) {
4301 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4302 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4303 donelist_init(&donelist);
4304 symlook_init_from_req(&req1, req);
4305 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4307 req->sym_out = req1.sym_out;
4308 req->defobj_out = req1.defobj_out;
4316 /* Symbol match routine common to both hash functions */
4318 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4319 const unsigned long symnum)
4322 const Elf_Sym *symp;
4325 symp = obj->symtab + symnum;
4326 strp = obj->strtab + symp->st_name;
4328 switch (ELF_ST_TYPE(symp->st_info)) {
4334 if (symp->st_value == 0)
4338 if (symp->st_shndx != SHN_UNDEF)
4341 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4342 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4349 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4352 if (req->ventry == NULL) {
4353 if (obj->versyms != NULL) {
4354 verndx = VER_NDX(obj->versyms[symnum]);
4355 if (verndx > obj->vernum) {
4357 "%s: symbol %s references wrong version %d",
4358 obj->path, obj->strtab + symnum, verndx);
4362 * If we are not called from dlsym (i.e. this
4363 * is a normal relocation from unversioned
4364 * binary), accept the symbol immediately if
4365 * it happens to have first version after this
4366 * shared object became versioned. Otherwise,
4367 * if symbol is versioned and not hidden,
4368 * remember it. If it is the only symbol with
4369 * this name exported by the shared object, it
4370 * will be returned as a match by the calling
4371 * function. If symbol is global (verndx < 2)
4372 * accept it unconditionally.
4374 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4375 verndx == VER_NDX_GIVEN) {
4376 result->sym_out = symp;
4379 else if (verndx >= VER_NDX_GIVEN) {
4380 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4382 if (result->vsymp == NULL)
4383 result->vsymp = symp;
4389 result->sym_out = symp;
4392 if (obj->versyms == NULL) {
4393 if (object_match_name(obj, req->ventry->name)) {
4394 _rtld_error("%s: object %s should provide version %s "
4395 "for symbol %s", obj_rtld.path, obj->path,
4396 req->ventry->name, obj->strtab + symnum);
4400 verndx = VER_NDX(obj->versyms[symnum]);
4401 if (verndx > obj->vernum) {
4402 _rtld_error("%s: symbol %s references wrong version %d",
4403 obj->path, obj->strtab + symnum, verndx);
4406 if (obj->vertab[verndx].hash != req->ventry->hash ||
4407 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4409 * Version does not match. Look if this is a
4410 * global symbol and if it is not hidden. If
4411 * global symbol (verndx < 2) is available,
4412 * use it. Do not return symbol if we are
4413 * called by dlvsym, because dlvsym looks for
4414 * a specific version and default one is not
4415 * what dlvsym wants.
4417 if ((req->flags & SYMLOOK_DLSYM) ||
4418 (verndx >= VER_NDX_GIVEN) ||
4419 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4423 result->sym_out = symp;
4428 * Search for symbol using SysV hash function.
4429 * obj->buckets is known not to be NULL at this point; the test for this was
4430 * performed with the obj->valid_hash_sysv assignment.
4433 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4435 unsigned long symnum;
4436 Sym_Match_Result matchres;
4438 matchres.sym_out = NULL;
4439 matchres.vsymp = NULL;
4440 matchres.vcount = 0;
4442 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4443 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4444 if (symnum >= obj->nchains)
4445 return (ESRCH); /* Bad object */
4447 if (matched_symbol(req, obj, &matchres, symnum)) {
4448 req->sym_out = matchres.sym_out;
4449 req->defobj_out = obj;
4453 if (matchres.vcount == 1) {
4454 req->sym_out = matchres.vsymp;
4455 req->defobj_out = obj;
4461 /* Search for symbol using GNU hash function */
4463 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4465 Elf_Addr bloom_word;
4466 const Elf32_Word *hashval;
4468 Sym_Match_Result matchres;
4469 unsigned int h1, h2;
4470 unsigned long symnum;
4472 matchres.sym_out = NULL;
4473 matchres.vsymp = NULL;
4474 matchres.vcount = 0;
4476 /* Pick right bitmask word from Bloom filter array */
4477 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4478 obj->maskwords_bm_gnu];
4480 /* Calculate modulus word size of gnu hash and its derivative */
4481 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4482 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4484 /* Filter out the "definitely not in set" queries */
4485 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4488 /* Locate hash chain and corresponding value element*/
4489 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4492 hashval = &obj->chain_zero_gnu[bucket];
4494 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4495 symnum = hashval - obj->chain_zero_gnu;
4496 if (matched_symbol(req, obj, &matchres, symnum)) {
4497 req->sym_out = matchres.sym_out;
4498 req->defobj_out = obj;
4502 } while ((*hashval++ & 1) == 0);
4503 if (matchres.vcount == 1) {
4504 req->sym_out = matchres.vsymp;
4505 req->defobj_out = obj;
4512 trace_loaded_objects(Obj_Entry *obj)
4514 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4517 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4520 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4521 fmt1 = "\t%o => %p (%x)\n";
4523 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4524 fmt2 = "\t%o (%x)\n";
4526 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4528 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4529 Needed_Entry *needed;
4530 const char *name, *path;
4535 if (list_containers && obj->needed != NULL)
4536 rtld_printf("%s:\n", obj->path);
4537 for (needed = obj->needed; needed; needed = needed->next) {
4538 if (needed->obj != NULL) {
4539 if (needed->obj->traced && !list_containers)
4541 needed->obj->traced = true;
4542 path = needed->obj->path;
4546 name = obj->strtab + needed->name;
4547 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4549 fmt = is_lib ? fmt1 : fmt2;
4550 while ((c = *fmt++) != '\0') {
4576 rtld_putstr(main_local);
4579 rtld_putstr(obj_main->path);
4586 rtld_printf("%d", sodp->sod_major);
4589 rtld_printf("%d", sodp->sod_minor);
4596 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4609 * Unload a dlopened object and its dependencies from memory and from
4610 * our data structures. It is assumed that the DAG rooted in the
4611 * object has already been unreferenced, and that the object has a
4612 * reference count of 0.
4615 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4617 Obj_Entry marker, *obj, *next;
4619 assert(root->refcount == 0);
4622 * Pass over the DAG removing unreferenced objects from
4623 * appropriate lists.
4625 unlink_object(root);
4627 /* Unmap all objects that are no longer referenced. */
4628 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4629 next = TAILQ_NEXT(obj, next);
4630 if (obj->marker || obj->refcount != 0)
4632 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4633 obj->mapsize, 0, obj->path);
4634 dbg("unloading \"%s\"", obj->path);
4636 * Unlink the object now to prevent new references from
4637 * being acquired while the bind lock is dropped in
4638 * recursive dlclose() invocations.
4640 TAILQ_REMOVE(&obj_list, obj, next);
4643 if (obj->filtees_loaded) {
4645 init_marker(&marker);
4646 TAILQ_INSERT_BEFORE(next, &marker, next);
4647 unload_filtees(obj, lockstate);
4648 next = TAILQ_NEXT(&marker, next);
4649 TAILQ_REMOVE(&obj_list, &marker, next);
4651 unload_filtees(obj, lockstate);
4653 release_object(obj);
4658 unlink_object(Obj_Entry *root)
4662 if (root->refcount == 0) {
4663 /* Remove the object from the RTLD_GLOBAL list. */
4664 objlist_remove(&list_global, root);
4666 /* Remove the object from all objects' DAG lists. */
4667 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4668 objlist_remove(&elm->obj->dldags, root);
4669 if (elm->obj != root)
4670 unlink_object(elm->obj);
4676 ref_dag(Obj_Entry *root)
4680 assert(root->dag_inited);
4681 STAILQ_FOREACH(elm, &root->dagmembers, link)
4682 elm->obj->refcount++;
4686 unref_dag(Obj_Entry *root)
4690 assert(root->dag_inited);
4691 STAILQ_FOREACH(elm, &root->dagmembers, link)
4692 elm->obj->refcount--;
4696 * Common code for MD __tls_get_addr().
4698 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4700 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4702 Elf_Addr *newdtv, *dtv;
4703 RtldLockState lockstate;
4707 /* Check dtv generation in case new modules have arrived */
4708 if (dtv[0] != tls_dtv_generation) {
4709 wlock_acquire(rtld_bind_lock, &lockstate);
4710 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4712 if (to_copy > tls_max_index)
4713 to_copy = tls_max_index;
4714 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4715 newdtv[0] = tls_dtv_generation;
4716 newdtv[1] = tls_max_index;
4718 lock_release(rtld_bind_lock, &lockstate);
4719 dtv = *dtvp = newdtv;
4722 /* Dynamically allocate module TLS if necessary */
4723 if (dtv[index + 1] == 0) {
4724 /* Signal safe, wlock will block out signals. */
4725 wlock_acquire(rtld_bind_lock, &lockstate);
4726 if (!dtv[index + 1])
4727 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4728 lock_release(rtld_bind_lock, &lockstate);
4730 return ((void *)(dtv[index + 1] + offset));
4734 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4739 /* Check dtv generation in case new modules have arrived */
4740 if (__predict_true(dtv[0] == tls_dtv_generation &&
4741 dtv[index + 1] != 0))
4742 return ((void *)(dtv[index + 1] + offset));
4743 return (tls_get_addr_slow(dtvp, index, offset));
4746 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4747 defined(__powerpc__) || defined(__riscv)
4750 * Return pointer to allocated TLS block
4753 get_tls_block_ptr(void *tcb, size_t tcbsize)
4755 size_t extra_size, post_size, pre_size, tls_block_size;
4756 size_t tls_init_align;
4758 tls_init_align = MAX(obj_main->tlsalign, 1);
4760 /* Compute fragments sizes. */
4761 extra_size = tcbsize - TLS_TCB_SIZE;
4762 post_size = calculate_tls_post_size(tls_init_align);
4763 tls_block_size = tcbsize + post_size;
4764 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4766 return ((char *)tcb - pre_size - extra_size);
4770 * Allocate Static TLS using the Variant I method.
4772 * For details on the layout, see lib/libc/gen/tls.c.
4774 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4775 * it is based on tls_last_offset, and TLS offsets here are really TCB
4776 * offsets, whereas libc's tls_static_space is just the executable's static
4780 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4784 Elf_Addr *dtv, **tcb;
4787 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4788 size_t tls_init_align;
4790 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4793 assert(tcbsize >= TLS_TCB_SIZE);
4794 maxalign = MAX(tcbalign, tls_static_max_align);
4795 tls_init_align = MAX(obj_main->tlsalign, 1);
4797 /* Compute fragmets sizes. */
4798 extra_size = tcbsize - TLS_TCB_SIZE;
4799 post_size = calculate_tls_post_size(tls_init_align);
4800 tls_block_size = tcbsize + post_size;
4801 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4802 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4804 /* Allocate whole TLS block */
4805 tls_block = malloc_aligned(tls_block_size, maxalign);
4806 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4808 if (oldtcb != NULL) {
4809 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4811 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4813 /* Adjust the DTV. */
4815 for (i = 0; i < dtv[1]; i++) {
4816 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4817 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4818 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4822 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4824 dtv[0] = tls_dtv_generation;
4825 dtv[1] = tls_max_index;
4827 for (obj = globallist_curr(objs); obj != NULL;
4828 obj = globallist_next(obj)) {
4829 if (obj->tlsoffset > 0) {
4830 addr = (Elf_Addr)tcb + obj->tlsoffset;
4831 if (obj->tlsinitsize > 0)
4832 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4833 if (obj->tlssize > obj->tlsinitsize)
4834 memset((void*)(addr + obj->tlsinitsize), 0,
4835 obj->tlssize - obj->tlsinitsize);
4836 dtv[obj->tlsindex + 1] = addr;
4845 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
4848 Elf_Addr tlsstart, tlsend;
4850 size_t dtvsize, i, tls_init_align;
4852 assert(tcbsize >= TLS_TCB_SIZE);
4853 tls_init_align = MAX(obj_main->tlsalign, 1);
4855 /* Compute fragments sizes. */
4856 post_size = calculate_tls_post_size(tls_init_align);
4858 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
4859 tlsend = (Elf_Addr)tcb + tls_static_space;
4861 dtv = *(Elf_Addr **)tcb;
4863 for (i = 0; i < dtvsize; i++) {
4864 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4865 free((void*)dtv[i+2]);
4869 free_aligned(get_tls_block_ptr(tcb, tcbsize));
4874 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4877 * Allocate Static TLS using the Variant II method.
4880 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4883 size_t size, ralign;
4885 Elf_Addr *dtv, *olddtv;
4886 Elf_Addr segbase, oldsegbase, addr;
4890 if (tls_static_max_align > ralign)
4891 ralign = tls_static_max_align;
4892 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4894 assert(tcbsize >= 2*sizeof(Elf_Addr));
4895 tls = malloc_aligned(size, ralign);
4896 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4898 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4899 ((Elf_Addr*)segbase)[0] = segbase;
4900 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4902 dtv[0] = tls_dtv_generation;
4903 dtv[1] = tls_max_index;
4907 * Copy the static TLS block over whole.
4909 oldsegbase = (Elf_Addr) oldtls;
4910 memcpy((void *)(segbase - tls_static_space),
4911 (const void *)(oldsegbase - tls_static_space),
4915 * If any dynamic TLS blocks have been created tls_get_addr(),
4918 olddtv = ((Elf_Addr**)oldsegbase)[1];
4919 for (i = 0; i < olddtv[1]; i++) {
4920 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4921 dtv[i+2] = olddtv[i+2];
4927 * We assume that this block was the one we created with
4928 * allocate_initial_tls().
4930 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4932 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4933 if (obj->marker || obj->tlsoffset == 0)
4935 addr = segbase - obj->tlsoffset;
4936 memset((void*)(addr + obj->tlsinitsize),
4937 0, obj->tlssize - obj->tlsinitsize);
4939 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4940 dtv[obj->tlsindex + 1] = addr;
4944 return (void*) segbase;
4948 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
4951 size_t size, ralign;
4953 Elf_Addr tlsstart, tlsend;
4956 * Figure out the size of the initial TLS block so that we can
4957 * find stuff which ___tls_get_addr() allocated dynamically.
4960 if (tls_static_max_align > ralign)
4961 ralign = tls_static_max_align;
4962 size = round(tls_static_space, ralign);
4964 dtv = ((Elf_Addr**)tls)[1];
4966 tlsend = (Elf_Addr) tls;
4967 tlsstart = tlsend - size;
4968 for (i = 0; i < dtvsize; i++) {
4969 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4970 free_aligned((void *)dtv[i + 2]);
4974 free_aligned((void *)tlsstart);
4981 * Allocate TLS block for module with given index.
4984 allocate_module_tls(int index)
4989 TAILQ_FOREACH(obj, &obj_list, next) {
4992 if (obj->tlsindex == index)
4996 _rtld_error("Can't find module with TLS index %d", index);
5000 p = malloc_aligned(obj->tlssize, obj->tlsalign);
5001 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5002 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5008 allocate_tls_offset(Obj_Entry *obj)
5015 if (obj->tlssize == 0) {
5016 obj->tls_done = true;
5020 if (tls_last_offset == 0)
5021 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
5023 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5024 obj->tlssize, obj->tlsalign);
5027 * If we have already fixed the size of the static TLS block, we
5028 * must stay within that size. When allocating the static TLS, we
5029 * leave a small amount of space spare to be used for dynamically
5030 * loading modules which use static TLS.
5032 if (tls_static_space != 0) {
5033 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5035 } else if (obj->tlsalign > tls_static_max_align) {
5036 tls_static_max_align = obj->tlsalign;
5039 tls_last_offset = obj->tlsoffset = off;
5040 tls_last_size = obj->tlssize;
5041 obj->tls_done = true;
5047 free_tls_offset(Obj_Entry *obj)
5051 * If we were the last thing to allocate out of the static TLS
5052 * block, we give our space back to the 'allocator'. This is a
5053 * simplistic workaround to allow libGL.so.1 to be loaded and
5054 * unloaded multiple times.
5056 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5057 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5058 tls_last_offset -= obj->tlssize;
5064 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5067 RtldLockState lockstate;
5069 wlock_acquire(rtld_bind_lock, &lockstate);
5070 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5072 lock_release(rtld_bind_lock, &lockstate);
5077 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5079 RtldLockState lockstate;
5081 wlock_acquire(rtld_bind_lock, &lockstate);
5082 free_tls(tcb, tcbsize, tcbalign);
5083 lock_release(rtld_bind_lock, &lockstate);
5087 object_add_name(Obj_Entry *obj, const char *name)
5093 entry = malloc(sizeof(Name_Entry) + len);
5095 if (entry != NULL) {
5096 strcpy(entry->name, name);
5097 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5102 object_match_name(const Obj_Entry *obj, const char *name)
5106 STAILQ_FOREACH(entry, &obj->names, link) {
5107 if (strcmp(name, entry->name) == 0)
5114 locate_dependency(const Obj_Entry *obj, const char *name)
5116 const Objlist_Entry *entry;
5117 const Needed_Entry *needed;
5119 STAILQ_FOREACH(entry, &list_main, link) {
5120 if (object_match_name(entry->obj, name))
5124 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5125 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5126 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5128 * If there is DT_NEEDED for the name we are looking for,
5129 * we are all set. Note that object might not be found if
5130 * dependency was not loaded yet, so the function can
5131 * return NULL here. This is expected and handled
5132 * properly by the caller.
5134 return (needed->obj);
5137 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5143 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5144 const Elf_Vernaux *vna)
5146 const Elf_Verdef *vd;
5147 const char *vername;
5149 vername = refobj->strtab + vna->vna_name;
5150 vd = depobj->verdef;
5152 _rtld_error("%s: version %s required by %s not defined",
5153 depobj->path, vername, refobj->path);
5157 if (vd->vd_version != VER_DEF_CURRENT) {
5158 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5159 depobj->path, vd->vd_version);
5162 if (vna->vna_hash == vd->vd_hash) {
5163 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5164 ((const char *)vd + vd->vd_aux);
5165 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5168 if (vd->vd_next == 0)
5170 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5172 if (vna->vna_flags & VER_FLG_WEAK)
5174 _rtld_error("%s: version %s required by %s not found",
5175 depobj->path, vername, refobj->path);
5180 rtld_verify_object_versions(Obj_Entry *obj)
5182 const Elf_Verneed *vn;
5183 const Elf_Verdef *vd;
5184 const Elf_Verdaux *vda;
5185 const Elf_Vernaux *vna;
5186 const Obj_Entry *depobj;
5187 int maxvernum, vernum;
5189 if (obj->ver_checked)
5191 obj->ver_checked = true;
5195 * Walk over defined and required version records and figure out
5196 * max index used by any of them. Do very basic sanity checking
5200 while (vn != NULL) {
5201 if (vn->vn_version != VER_NEED_CURRENT) {
5202 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5203 obj->path, vn->vn_version);
5206 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5208 vernum = VER_NEED_IDX(vna->vna_other);
5209 if (vernum > maxvernum)
5211 if (vna->vna_next == 0)
5213 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5215 if (vn->vn_next == 0)
5217 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5221 while (vd != NULL) {
5222 if (vd->vd_version != VER_DEF_CURRENT) {
5223 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5224 obj->path, vd->vd_version);
5227 vernum = VER_DEF_IDX(vd->vd_ndx);
5228 if (vernum > maxvernum)
5230 if (vd->vd_next == 0)
5232 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5239 * Store version information in array indexable by version index.
5240 * Verify that object version requirements are satisfied along the
5243 obj->vernum = maxvernum + 1;
5244 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5247 while (vd != NULL) {
5248 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5249 vernum = VER_DEF_IDX(vd->vd_ndx);
5250 assert(vernum <= maxvernum);
5251 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5252 obj->vertab[vernum].hash = vd->vd_hash;
5253 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5254 obj->vertab[vernum].file = NULL;
5255 obj->vertab[vernum].flags = 0;
5257 if (vd->vd_next == 0)
5259 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5263 while (vn != NULL) {
5264 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5267 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5269 if (check_object_provided_version(obj, depobj, vna))
5271 vernum = VER_NEED_IDX(vna->vna_other);
5272 assert(vernum <= maxvernum);
5273 obj->vertab[vernum].hash = vna->vna_hash;
5274 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5275 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5276 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5277 VER_INFO_HIDDEN : 0;
5278 if (vna->vna_next == 0)
5280 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5282 if (vn->vn_next == 0)
5284 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5290 rtld_verify_versions(const Objlist *objlist)
5292 Objlist_Entry *entry;
5296 STAILQ_FOREACH(entry, objlist, link) {
5298 * Skip dummy objects or objects that have their version requirements
5301 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5303 if (rtld_verify_object_versions(entry->obj) == -1) {
5305 if (ld_tracing == NULL)
5309 if (rc == 0 || ld_tracing != NULL)
5310 rc = rtld_verify_object_versions(&obj_rtld);
5315 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5320 vernum = VER_NDX(obj->versyms[symnum]);
5321 if (vernum >= obj->vernum) {
5322 _rtld_error("%s: symbol %s has wrong verneed value %d",
5323 obj->path, obj->strtab + symnum, vernum);
5324 } else if (obj->vertab[vernum].hash != 0) {
5325 return &obj->vertab[vernum];
5332 _rtld_get_stack_prot(void)
5335 return (stack_prot);
5339 _rtld_is_dlopened(void *arg)
5342 RtldLockState lockstate;
5345 rlock_acquire(rtld_bind_lock, &lockstate);
5348 obj = obj_from_addr(arg);
5350 _rtld_error("No shared object contains address");
5351 lock_release(rtld_bind_lock, &lockstate);
5354 res = obj->dlopened ? 1 : 0;
5355 lock_release(rtld_bind_lock, &lockstate);
5360 obj_remap_relro(Obj_Entry *obj, int prot)
5363 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5365 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5366 obj->path, prot, rtld_strerror(errno));
5373 obj_disable_relro(Obj_Entry *obj)
5376 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5380 obj_enforce_relro(Obj_Entry *obj)
5383 return (obj_remap_relro(obj, PROT_READ));
5387 map_stacks_exec(RtldLockState *lockstate)
5389 void (*thr_map_stacks_exec)(void);
5391 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5393 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5394 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5395 if (thr_map_stacks_exec != NULL) {
5396 stack_prot |= PROT_EXEC;
5397 thr_map_stacks_exec();
5402 symlook_init(SymLook *dst, const char *name)
5405 bzero(dst, sizeof(*dst));
5407 dst->hash = elf_hash(name);
5408 dst->hash_gnu = gnu_hash(name);
5412 symlook_init_from_req(SymLook *dst, const SymLook *src)
5415 dst->name = src->name;
5416 dst->hash = src->hash;
5417 dst->hash_gnu = src->hash_gnu;
5418 dst->ventry = src->ventry;
5419 dst->flags = src->flags;
5420 dst->defobj_out = NULL;
5421 dst->sym_out = NULL;
5422 dst->lockstate = src->lockstate;
5426 open_binary_fd(const char *argv0, bool search_in_path)
5428 char *pathenv, *pe, binpath[PATH_MAX];
5431 if (search_in_path && strchr(argv0, '/') == NULL) {
5432 pathenv = getenv("PATH");
5433 if (pathenv == NULL) {
5434 _rtld_error("-p and no PATH environment variable");
5437 pathenv = strdup(pathenv);
5438 if (pathenv == NULL) {
5439 _rtld_error("Cannot allocate memory");
5444 while ((pe = strsep(&pathenv, ":")) != NULL) {
5445 if (strlcpy(binpath, pe, sizeof(binpath)) >=
5448 if (binpath[0] != '\0' &&
5449 strlcat(binpath, "/", sizeof(binpath)) >=
5452 if (strlcat(binpath, argv0, sizeof(binpath)) >=
5455 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5456 if (fd != -1 || errno != ENOENT)
5461 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5465 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5472 * Parse a set of command-line arguments.
5475 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp)
5478 int fd, i, j, arglen;
5481 dbg("Parsing command-line arguments");
5485 for (i = 1; i < argc; i++ ) {
5487 dbg("argv[%d]: '%s'", i, arg);
5490 * rtld arguments end with an explicit "--" or with the first
5491 * non-prefixed argument.
5493 if (strcmp(arg, "--") == 0) {
5501 * All other arguments are single-character options that can
5502 * be combined, so we need to search through `arg` for them.
5504 arglen = strlen(arg);
5505 for (j = 1; j < arglen; j++) {
5508 print_usage(argv[0]);
5510 } else if (opt == 'f') {
5512 * -f XX can be used to specify a descriptor for the
5513 * binary named at the command line (i.e., the later
5514 * argument will specify the process name but the
5515 * descriptor is what will actually be executed)
5517 if (j != arglen - 1) {
5518 /* -f must be the last option in, e.g., -abcf */
5519 _rtld_error("Invalid options: %s", arg);
5523 fd = parse_integer(argv[i]);
5525 _rtld_error("Invalid file descriptor: '%s'",
5531 } else if (opt == 'p') {
5534 _rtld_error("Invalid argument: '%s'", arg);
5535 print_usage(argv[0]);
5545 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5548 parse_integer(const char *str)
5550 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5557 for (c = *str; c != '\0'; c = *++str) {
5558 if (c < '0' || c > '9')
5565 /* Make sure we actually parsed something. */
5572 print_usage(const char *argv0)
5575 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n"
5578 " -h Display this help message\n"
5579 " -p Search in PATH for named binary\n"
5580 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5581 " -- End of RTLD options\n"
5582 " <binary> Name of process to execute\n"
5583 " <args> Arguments to the executed process\n", argv0);
5587 * Overrides for libc_pic-provided functions.
5591 __getosreldate(void)
5601 oid[1] = KERN_OSRELDATE;
5603 len = sizeof(osrel);
5604 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5605 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5617 void (*__cleanup)(void);
5618 int __isthreaded = 0;
5619 int _thread_autoinit_dummy_decl = 1;
5622 * No unresolved symbols for rtld.
5625 __pthread_cxa_finalize(struct dl_phdr_info *a __unused)
5630 rtld_strerror(int errnum)
5633 if (errnum < 0 || errnum >= sys_nerr)
5634 return ("Unknown error");
5635 return (sys_errlist[errnum]);
5639 * No ifunc relocations.
5642 memset(void *dest, int c, size_t len)
5646 for (i = 0; i < len; i++)
5647 ((char *)dest)[i] = c;
5652 bzero(void *dest, size_t len)
5656 for (i = 0; i < len; i++)
5657 ((char *)dest)[i] = 0;