2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
6 * Copyright 2014-2017 The FreeBSD Foundation
9 * Portions of this software were developed by Konstantin Belousov
10 * under sponsorship from the FreeBSD Foundation.
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 * Dynamic linker for ELF.
36 * John Polstra <jdp@polstra.com>.
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
42 #include <sys/param.h>
43 #include <sys/mount.h>
46 #include <sys/sysctl.h>
48 #include <sys/utsname.h>
49 #include <sys/ktrace.h>
66 #include "rtld_printf.h"
67 #include "rtld_utrace.h"
71 typedef void (*func_ptr_type)();
72 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
75 * Function declarations.
77 static const char *basename(const char *);
78 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
79 const Elf_Dyn **, const Elf_Dyn **);
80 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
82 static void digest_dynamic(Obj_Entry *, int);
83 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
84 static void distribute_static_tls(Objlist *, RtldLockState *);
85 static Obj_Entry *dlcheck(void *);
86 static int dlclose_locked(void *, RtldLockState *);
87 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
88 int lo_flags, int mode, RtldLockState *lockstate);
89 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
90 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
91 static bool donelist_check(DoneList *, const Obj_Entry *);
92 static void errmsg_restore(char *);
93 static char *errmsg_save(void);
94 static void *fill_search_info(const char *, size_t, void *);
95 static char *find_library(const char *, const Obj_Entry *, int *);
96 static const char *gethints(bool);
97 static void hold_object(Obj_Entry *);
98 static void unhold_object(Obj_Entry *);
99 static void init_dag(Obj_Entry *);
100 static void init_marker(Obj_Entry *);
101 static void init_pagesizes(Elf_Auxinfo **aux_info);
102 static void init_rtld(caddr_t, Elf_Auxinfo **);
103 static void initlist_add_neededs(Needed_Entry *, Objlist *);
104 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
105 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
106 static void linkmap_add(Obj_Entry *);
107 static void linkmap_delete(Obj_Entry *);
108 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
109 static void unload_filtees(Obj_Entry *, RtldLockState *);
110 static int load_needed_objects(Obj_Entry *, int);
111 static int load_preload_objects(void);
112 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
113 static void map_stacks_exec(RtldLockState *);
114 static int obj_disable_relro(Obj_Entry *);
115 static int obj_enforce_relro(Obj_Entry *);
116 static Obj_Entry *obj_from_addr(const void *);
117 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
118 static void objlist_call_init(Objlist *, RtldLockState *);
119 static void objlist_clear(Objlist *);
120 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
121 static void objlist_init(Objlist *);
122 static void objlist_push_head(Objlist *, Obj_Entry *);
123 static void objlist_push_tail(Objlist *, Obj_Entry *);
124 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
125 static void objlist_remove(Objlist *, Obj_Entry *);
126 static int open_binary_fd(const char *argv0, bool search_in_path);
127 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp);
128 static int parse_integer(const char *);
129 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
130 static void print_usage(const char *argv0);
131 static void release_object(Obj_Entry *);
132 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
133 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
134 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
135 int flags, RtldLockState *lockstate);
136 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
138 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
139 static int rtld_dirname(const char *, char *);
140 static int rtld_dirname_abs(const char *, char *);
141 static void *rtld_dlopen(const char *name, int fd, int mode);
142 static void rtld_exit(void);
143 static char *search_library_path(const char *, const char *, const char *,
145 static char *search_library_pathfds(const char *, const char *, int *);
146 static const void **get_program_var_addr(const char *, RtldLockState *);
147 static void set_program_var(const char *, const void *);
148 static int symlook_default(SymLook *, const Obj_Entry *refobj);
149 static int symlook_global(SymLook *, DoneList *);
150 static void symlook_init_from_req(SymLook *, const SymLook *);
151 static int symlook_list(SymLook *, const Objlist *, DoneList *);
152 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
153 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
154 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
155 static void trace_loaded_objects(Obj_Entry *);
156 static void unlink_object(Obj_Entry *);
157 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
158 static void unref_dag(Obj_Entry *);
159 static void ref_dag(Obj_Entry *);
160 static char *origin_subst_one(Obj_Entry *, char *, const char *,
162 static char *origin_subst(Obj_Entry *, char *);
163 static bool obj_resolve_origin(Obj_Entry *obj);
164 static void preinit_main(void);
165 static int rtld_verify_versions(const Objlist *);
166 static int rtld_verify_object_versions(Obj_Entry *);
167 static void object_add_name(Obj_Entry *, const char *);
168 static int object_match_name(const Obj_Entry *, const char *);
169 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
170 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
171 struct dl_phdr_info *phdr_info);
172 static uint32_t gnu_hash(const char *);
173 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
174 const unsigned long);
176 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
177 void _r_debug_postinit(struct link_map *) __noinline __exported;
179 int __sys_openat(int, const char *, int, ...);
184 static char *error_message; /* Message for dlerror(), or NULL */
185 struct r_debug r_debug __exported; /* for GDB; */
186 static bool libmap_disable; /* Disable libmap */
187 static bool ld_loadfltr; /* Immediate filters processing */
188 static char *libmap_override; /* Maps to use in addition to libmap.conf */
189 static bool trust; /* False for setuid and setgid programs */
190 static bool dangerous_ld_env; /* True if environment variables have been
191 used to affect the libraries loaded */
192 bool ld_bind_not; /* Disable PLT update */
193 static char *ld_bind_now; /* Environment variable for immediate binding */
194 static char *ld_debug; /* Environment variable for debugging */
195 static char *ld_library_path; /* Environment variable for search path */
196 static char *ld_library_dirs; /* Environment variable for library descriptors */
197 static char *ld_preload; /* Environment variable for libraries to
199 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
200 static char *ld_tracing; /* Called from ldd to print libs */
201 static char *ld_utrace; /* Use utrace() to log events. */
202 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
203 static Obj_Entry *obj_main; /* The main program shared object */
204 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
205 static unsigned int obj_count; /* Number of objects in obj_list */
206 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
208 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
209 STAILQ_HEAD_INITIALIZER(list_global);
210 static Objlist list_main = /* Objects loaded at program startup */
211 STAILQ_HEAD_INITIALIZER(list_main);
212 static Objlist list_fini = /* Objects needing fini() calls */
213 STAILQ_HEAD_INITIALIZER(list_fini);
215 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
217 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
219 extern Elf_Dyn _DYNAMIC;
220 #pragma weak _DYNAMIC
222 int dlclose(void *) __exported;
223 char *dlerror(void) __exported;
224 void *dlopen(const char *, int) __exported;
225 void *fdlopen(int, int) __exported;
226 void *dlsym(void *, const char *) __exported;
227 dlfunc_t dlfunc(void *, const char *) __exported;
228 void *dlvsym(void *, const char *, const char *) __exported;
229 int dladdr(const void *, Dl_info *) __exported;
230 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
231 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
232 int dlinfo(void *, int , void *) __exported;
233 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
234 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
235 int _rtld_get_stack_prot(void) __exported;
236 int _rtld_is_dlopened(void *) __exported;
237 void _rtld_error(const char *, ...) __exported;
239 int npagesizes, osreldate;
242 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
244 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
245 static int max_stack_flags;
248 * Global declarations normally provided by crt1. The dynamic linker is
249 * not built with crt1, so we have to provide them ourselves.
255 * Used to pass argc, argv to init functions.
261 * Globals to control TLS allocation.
263 size_t tls_last_offset; /* Static TLS offset of last module */
264 size_t tls_last_size; /* Static TLS size of last module */
265 size_t tls_static_space; /* Static TLS space allocated */
266 size_t tls_static_max_align;
267 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
268 int tls_max_index = 1; /* Largest module index allocated */
270 bool ld_library_path_rpath = false;
273 * Globals for path names, and such
275 char *ld_elf_hints_default = _PATH_ELF_HINTS;
276 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
277 char *ld_path_rtld = _PATH_RTLD;
278 char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
279 char *ld_env_prefix = LD_;
282 * Fill in a DoneList with an allocation large enough to hold all of
283 * the currently-loaded objects. Keep this as a macro since it calls
284 * alloca and we want that to occur within the scope of the caller.
286 #define donelist_init(dlp) \
287 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
288 assert((dlp)->objs != NULL), \
289 (dlp)->num_alloc = obj_count, \
292 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
293 if (ld_utrace != NULL) \
294 ld_utrace_log(e, h, mb, ms, r, n); \
298 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
299 int refcnt, const char *name)
301 struct utrace_rtld ut;
302 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
304 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
307 ut.mapbase = mapbase;
308 ut.mapsize = mapsize;
310 bzero(ut.name, sizeof(ut.name));
312 strlcpy(ut.name, name, sizeof(ut.name));
313 utrace(&ut, sizeof(ut));
316 #ifdef RTLD_VARIANT_ENV_NAMES
318 * construct the env variable based on the type of binary that's
321 static inline const char *
324 static char buffer[128];
326 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
327 strlcat(buffer, var, sizeof(buffer));
335 * Main entry point for dynamic linking. The first argument is the
336 * stack pointer. The stack is expected to be laid out as described
337 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
338 * Specifically, the stack pointer points to a word containing
339 * ARGC. Following that in the stack is a null-terminated sequence
340 * of pointers to argument strings. Then comes a null-terminated
341 * sequence of pointers to environment strings. Finally, there is a
342 * sequence of "auxiliary vector" entries.
344 * The second argument points to a place to store the dynamic linker's
345 * exit procedure pointer and the third to a place to store the main
348 * The return value is the main program's entry point.
351 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
353 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
354 Objlist_Entry *entry;
355 Obj_Entry *last_interposer, *obj, *preload_tail;
356 const Elf_Phdr *phdr;
358 RtldLockState lockstate;
361 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath;
363 char buf[MAXPATHLEN];
364 int argc, fd, i, mib[2], phnum, rtld_argc;
366 bool dir_enable, explicit_fd, search_in_path;
369 * On entry, the dynamic linker itself has not been relocated yet.
370 * Be very careful not to reference any global data until after
371 * init_rtld has returned. It is OK to reference file-scope statics
372 * and string constants, and to call static and global functions.
375 /* Find the auxiliary vector on the stack. */
379 sp += argc + 1; /* Skip over arguments and NULL terminator */
381 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
383 aux = (Elf_Auxinfo *) sp;
385 /* Digest the auxiliary vector. */
386 for (i = 0; i < AT_COUNT; i++)
388 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
389 if (auxp->a_type < AT_COUNT)
390 aux_info[auxp->a_type] = auxp;
393 /* Initialize and relocate ourselves. */
394 assert(aux_info[AT_BASE] != NULL);
395 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
397 __progname = obj_rtld.path;
398 argv0 = argv[0] != NULL ? argv[0] : "(null)";
403 if (aux_info[AT_CANARY] != NULL &&
404 aux_info[AT_CANARY]->a_un.a_ptr != NULL) {
405 i = aux_info[AT_CANARYLEN]->a_un.a_val;
406 if (i > sizeof(__stack_chk_guard))
407 i = sizeof(__stack_chk_guard);
408 memcpy(__stack_chk_guard, aux_info[AT_CANARY]->a_un.a_ptr, i);
413 len = sizeof(__stack_chk_guard);
414 if (sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
415 len != sizeof(__stack_chk_guard)) {
416 /* If sysctl was unsuccessful, use the "terminator canary". */
417 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
418 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
419 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
420 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
424 trust = !issetugid();
426 md_abi_variant_hook(aux_info);
429 if (aux_info[AT_EXECFD] != NULL) {
430 fd = aux_info[AT_EXECFD]->a_un.a_val;
432 assert(aux_info[AT_PHDR] != NULL);
433 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
434 if (phdr == obj_rtld.phdr) {
436 rtld_printf("Tainted process refusing to run binary %s\n",
440 dbg("opening main program in direct exec mode");
442 rtld_argc = parse_args(argv, argc, &search_in_path, &fd);
443 argv0 = argv[rtld_argc];
444 explicit_fd = (fd != -1);
446 fd = open_binary_fd(argv0, search_in_path);
447 if (fstat(fd, &st) == -1) {
448 _rtld_error("failed to fstat FD %d (%s): %s", fd,
449 explicit_fd ? "user-provided descriptor" : argv0,
450 rtld_strerror(errno));
455 * Rough emulation of the permission checks done by
456 * execve(2), only Unix DACs are checked, ACLs are
457 * ignored. Preserve the semantic of disabling owner
458 * to execute if owner x bit is cleared, even if
459 * others x bit is enabled.
460 * mmap(2) does not allow to mmap with PROT_EXEC if
461 * binary' file comes from noexec mount. We cannot
462 * set VV_TEXT on the binary.
465 if (st.st_uid == geteuid()) {
466 if ((st.st_mode & S_IXUSR) != 0)
468 } else if (st.st_gid == getegid()) {
469 if ((st.st_mode & S_IXGRP) != 0)
471 } else if ((st.st_mode & S_IXOTH) != 0) {
475 rtld_printf("No execute permission for binary %s\n",
481 * For direct exec mode, argv[0] is the interpreter
482 * name, we must remove it and shift arguments left
483 * before invoking binary main. Since stack layout
484 * places environment pointers and aux vectors right
485 * after the terminating NULL, we must shift
486 * environment and aux as well.
488 main_argc = argc - rtld_argc;
489 for (i = 0; i <= main_argc; i++)
490 argv[i] = argv[i + rtld_argc];
492 environ = env = envp = argv + main_argc + 1;
494 *envp = *(envp + rtld_argc);
496 } while (*envp != NULL);
497 aux = auxp = (Elf_Auxinfo *)envp;
498 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
499 for (;; auxp++, auxpf++) {
501 if (auxp->a_type == AT_NULL)
505 rtld_printf("no binary\n");
511 ld_bind_now = getenv(_LD("BIND_NOW"));
514 * If the process is tainted, then we un-set the dangerous environment
515 * variables. The process will be marked as tainted until setuid(2)
516 * is called. If any child process calls setuid(2) we do not want any
517 * future processes to honor the potentially un-safe variables.
520 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
521 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
522 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
523 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
524 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
525 _rtld_error("environment corrupt; aborting");
529 ld_debug = getenv(_LD("DEBUG"));
530 if (ld_bind_now == NULL)
531 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
532 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
533 libmap_override = getenv(_LD("LIBMAP"));
534 ld_library_path = getenv(_LD("LIBRARY_PATH"));
535 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
536 ld_preload = getenv(_LD("PRELOAD"));
537 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
538 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
539 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
540 if (library_path_rpath != NULL) {
541 if (library_path_rpath[0] == 'y' ||
542 library_path_rpath[0] == 'Y' ||
543 library_path_rpath[0] == '1')
544 ld_library_path_rpath = true;
546 ld_library_path_rpath = false;
548 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
549 (ld_library_path != NULL) || (ld_preload != NULL) ||
550 (ld_elf_hints_path != NULL) || ld_loadfltr;
551 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
552 ld_utrace = getenv(_LD("UTRACE"));
554 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
555 ld_elf_hints_path = ld_elf_hints_default;
557 if (ld_debug != NULL && *ld_debug != '\0')
559 dbg("%s is initialized, base address = %p", __progname,
560 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
561 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
562 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
564 dbg("initializing thread locks");
568 * Load the main program, or process its program header if it is
571 if (fd != -1) { /* Load the main program. */
572 dbg("loading main program");
573 obj_main = map_object(fd, argv0, NULL);
575 if (obj_main == NULL)
577 max_stack_flags = obj_main->stack_flags;
578 } else { /* Main program already loaded. */
579 dbg("processing main program's program header");
580 assert(aux_info[AT_PHDR] != NULL);
581 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
582 assert(aux_info[AT_PHNUM] != NULL);
583 phnum = aux_info[AT_PHNUM]->a_un.a_val;
584 assert(aux_info[AT_PHENT] != NULL);
585 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
586 assert(aux_info[AT_ENTRY] != NULL);
587 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
588 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
592 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
593 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
594 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
595 if (kexecpath[0] == '/')
596 obj_main->path = kexecpath;
597 else if (getcwd(buf, sizeof(buf)) == NULL ||
598 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
599 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
600 obj_main->path = xstrdup(argv0);
602 obj_main->path = xstrdup(buf);
604 dbg("No AT_EXECPATH or direct exec");
605 obj_main->path = xstrdup(argv0);
607 dbg("obj_main path %s", obj_main->path);
608 obj_main->mainprog = true;
610 if (aux_info[AT_STACKPROT] != NULL &&
611 aux_info[AT_STACKPROT]->a_un.a_val != 0)
612 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
616 * Get the actual dynamic linker pathname from the executable if
617 * possible. (It should always be possible.) That ensures that
618 * gdb will find the right dynamic linker even if a non-standard
621 if (obj_main->interp != NULL &&
622 strcmp(obj_main->interp, obj_rtld.path) != 0) {
624 obj_rtld.path = xstrdup(obj_main->interp);
625 __progname = obj_rtld.path;
629 digest_dynamic(obj_main, 0);
630 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
631 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
632 obj_main->dynsymcount);
634 linkmap_add(obj_main);
635 linkmap_add(&obj_rtld);
637 /* Link the main program into the list of objects. */
638 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
642 /* Initialize a fake symbol for resolving undefined weak references. */
643 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
644 sym_zero.st_shndx = SHN_UNDEF;
645 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
648 libmap_disable = (bool)lm_init(libmap_override);
650 dbg("loading LD_PRELOAD libraries");
651 if (load_preload_objects() == -1)
653 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
655 dbg("loading needed objects");
656 if (load_needed_objects(obj_main, 0) == -1)
659 /* Make a list of all objects loaded at startup. */
660 last_interposer = obj_main;
661 TAILQ_FOREACH(obj, &obj_list, next) {
664 if (obj->z_interpose && obj != obj_main) {
665 objlist_put_after(&list_main, last_interposer, obj);
666 last_interposer = obj;
668 objlist_push_tail(&list_main, obj);
673 dbg("checking for required versions");
674 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
677 if (ld_tracing) { /* We're done */
678 trace_loaded_objects(obj_main);
682 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
683 dump_relocations(obj_main);
688 * Processing tls relocations requires having the tls offsets
689 * initialized. Prepare offsets before starting initial
690 * relocation processing.
692 dbg("initializing initial thread local storage offsets");
693 STAILQ_FOREACH(entry, &list_main, link) {
695 * Allocate all the initial objects out of the static TLS
696 * block even if they didn't ask for it.
698 allocate_tls_offset(entry->obj);
701 if (relocate_objects(obj_main,
702 ld_bind_now != NULL && *ld_bind_now != '\0',
703 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
706 dbg("doing copy relocations");
707 if (do_copy_relocations(obj_main) == -1)
710 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
711 dump_relocations(obj_main);
718 * Setup TLS for main thread. This must be done after the
719 * relocations are processed, since tls initialization section
720 * might be the subject for relocations.
722 dbg("initializing initial thread local storage");
723 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
725 dbg("initializing key program variables");
726 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
727 set_program_var("environ", env);
728 set_program_var("__elf_aux_vector", aux);
730 /* Make a list of init functions to call. */
731 objlist_init(&initlist);
732 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
733 preload_tail, &initlist);
735 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
737 map_stacks_exec(NULL);
739 if (!obj_main->crt_no_init) {
741 * Make sure we don't call the main program's init and fini
742 * functions for binaries linked with old crt1 which calls
745 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
746 obj_main->preinit_array = obj_main->init_array =
747 obj_main->fini_array = (Elf_Addr)NULL;
751 * Execute MD initializers required before we call the objects'
756 wlock_acquire(rtld_bind_lock, &lockstate);
758 dbg("resolving ifuncs");
759 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
760 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
763 if (obj_main->crt_no_init)
765 objlist_call_init(&initlist, &lockstate);
766 _r_debug_postinit(&obj_main->linkmap);
767 objlist_clear(&initlist);
768 dbg("loading filtees");
769 TAILQ_FOREACH(obj, &obj_list, next) {
772 if (ld_loadfltr || obj->z_loadfltr)
773 load_filtees(obj, 0, &lockstate);
776 dbg("enforcing main obj relro");
777 if (obj_enforce_relro(obj_main) == -1)
780 lock_release(rtld_bind_lock, &lockstate);
782 dbg("transferring control to program entry point = %p", obj_main->entry);
784 /* Return the exit procedure and the program entry point. */
785 *exit_proc = rtld_exit;
787 return (func_ptr_type) obj_main->entry;
791 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
796 ptr = (void *)make_function_pointer(def, obj);
797 target = call_ifunc_resolver(ptr);
798 return ((void *)target);
802 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
803 * Changes to this function should be applied there as well.
806 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
810 const Obj_Entry *defobj;
813 RtldLockState lockstate;
815 rlock_acquire(rtld_bind_lock, &lockstate);
816 if (sigsetjmp(lockstate.env, 0) != 0)
817 lock_upgrade(rtld_bind_lock, &lockstate);
819 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
821 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
823 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
824 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
828 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
829 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
831 target = (Elf_Addr)(defobj->relocbase + def->st_value);
833 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
834 defobj->strtab + def->st_name, basename(obj->path),
835 (void *)target, basename(defobj->path));
838 * Write the new contents for the jmpslot. Note that depending on
839 * architecture, the value which we need to return back to the
840 * lazy binding trampoline may or may not be the target
841 * address. The value returned from reloc_jmpslot() is the value
842 * that the trampoline needs.
844 target = reloc_jmpslot(where, target, defobj, obj, rel);
845 lock_release(rtld_bind_lock, &lockstate);
850 * Error reporting function. Use it like printf. If formats the message
851 * into a buffer, and sets things up so that the next call to dlerror()
852 * will return the message.
855 _rtld_error(const char *fmt, ...)
857 static char buf[512];
861 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
867 * Return a dynamically-allocated copy of the current error message, if any.
872 return error_message == NULL ? NULL : xstrdup(error_message);
876 * Restore the current error message from a copy which was previously saved
877 * by errmsg_save(). The copy is freed.
880 errmsg_restore(char *saved_msg)
882 if (saved_msg == NULL)
883 error_message = NULL;
885 _rtld_error("%s", saved_msg);
891 basename(const char *name)
893 const char *p = strrchr(name, '/');
894 return p != NULL ? p + 1 : name;
897 static struct utsname uts;
900 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
901 const char *subst, bool may_free)
903 char *p, *p1, *res, *resp;
904 int subst_len, kw_len, subst_count, old_len, new_len;
909 * First, count the number of the keyword occurrences, to
910 * preallocate the final string.
912 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
919 * If the keyword is not found, just return.
921 * Return non-substituted string if resolution failed. We
922 * cannot do anything more reasonable, the failure mode of the
923 * caller is unresolved library anyway.
925 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
926 return (may_free ? real : xstrdup(real));
928 subst = obj->origin_path;
931 * There is indeed something to substitute. Calculate the
932 * length of the resulting string, and allocate it.
934 subst_len = strlen(subst);
935 old_len = strlen(real);
936 new_len = old_len + (subst_len - kw_len) * subst_count;
937 res = xmalloc(new_len + 1);
940 * Now, execute the substitution loop.
942 for (p = real, resp = res, *resp = '\0';;) {
945 /* Copy the prefix before keyword. */
946 memcpy(resp, p, p1 - p);
948 /* Keyword replacement. */
949 memcpy(resp, subst, subst_len);
957 /* Copy to the end of string and finish. */
965 origin_subst(Obj_Entry *obj, char *real)
967 char *res1, *res2, *res3, *res4;
969 if (obj == NULL || !trust)
970 return (xstrdup(real));
971 if (uts.sysname[0] == '\0') {
972 if (uname(&uts) != 0) {
973 _rtld_error("utsname failed: %d", errno);
977 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
978 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
979 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
980 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
987 const char *msg = dlerror();
991 rtld_fdputstr(STDERR_FILENO, msg);
992 rtld_fdputchar(STDERR_FILENO, '\n');
997 * Process a shared object's DYNAMIC section, and save the important
998 * information in its Obj_Entry structure.
1001 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1002 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1004 const Elf_Dyn *dynp;
1005 Needed_Entry **needed_tail = &obj->needed;
1006 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1007 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1008 const Elf_Hashelt *hashtab;
1009 const Elf32_Word *hashval;
1010 Elf32_Word bkt, nmaskwords;
1012 int plttype = DT_REL;
1016 *dyn_runpath = NULL;
1018 obj->bind_now = false;
1019 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
1020 switch (dynp->d_tag) {
1023 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
1027 obj->relsize = dynp->d_un.d_val;
1031 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1035 obj->pltrel = (const Elf_Rel *)
1036 (obj->relocbase + dynp->d_un.d_ptr);
1040 obj->pltrelsize = dynp->d_un.d_val;
1044 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
1048 obj->relasize = dynp->d_un.d_val;
1052 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1056 plttype = dynp->d_un.d_val;
1057 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1061 obj->symtab = (const Elf_Sym *)
1062 (obj->relocbase + dynp->d_un.d_ptr);
1066 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1070 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
1074 obj->strsize = dynp->d_un.d_val;
1078 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
1083 obj->verneednum = dynp->d_un.d_val;
1087 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1092 obj->verdefnum = dynp->d_un.d_val;
1096 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1102 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1104 obj->nbuckets = hashtab[0];
1105 obj->nchains = hashtab[1];
1106 obj->buckets = hashtab + 2;
1107 obj->chains = obj->buckets + obj->nbuckets;
1108 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1109 obj->buckets != NULL;
1115 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1117 obj->nbuckets_gnu = hashtab[0];
1118 obj->symndx_gnu = hashtab[1];
1119 nmaskwords = hashtab[2];
1120 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1121 obj->maskwords_bm_gnu = nmaskwords - 1;
1122 obj->shift2_gnu = hashtab[3];
1123 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1124 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1125 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1127 /* Number of bitmask words is required to be power of 2 */
1128 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1129 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1135 Needed_Entry *nep = NEW(Needed_Entry);
1136 nep->name = dynp->d_un.d_val;
1141 needed_tail = &nep->next;
1147 Needed_Entry *nep = NEW(Needed_Entry);
1148 nep->name = dynp->d_un.d_val;
1152 *needed_filtees_tail = nep;
1153 needed_filtees_tail = &nep->next;
1159 Needed_Entry *nep = NEW(Needed_Entry);
1160 nep->name = dynp->d_un.d_val;
1164 *needed_aux_filtees_tail = nep;
1165 needed_aux_filtees_tail = &nep->next;
1170 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1174 obj->textrel = true;
1178 obj->symbolic = true;
1183 * We have to wait until later to process this, because we
1184 * might not have gotten the address of the string table yet.
1194 *dyn_runpath = dynp;
1198 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1201 case DT_PREINIT_ARRAY:
1202 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1205 case DT_PREINIT_ARRAYSZ:
1206 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1210 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1213 case DT_INIT_ARRAYSZ:
1214 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1218 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1222 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1225 case DT_FINI_ARRAYSZ:
1226 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1230 * Don't process DT_DEBUG on MIPS as the dynamic section
1231 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1237 dbg("Filling in DT_DEBUG entry");
1238 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1243 if (dynp->d_un.d_val & DF_ORIGIN)
1244 obj->z_origin = true;
1245 if (dynp->d_un.d_val & DF_SYMBOLIC)
1246 obj->symbolic = true;
1247 if (dynp->d_un.d_val & DF_TEXTREL)
1248 obj->textrel = true;
1249 if (dynp->d_un.d_val & DF_BIND_NOW)
1250 obj->bind_now = true;
1251 if (dynp->d_un.d_val & DF_STATIC_TLS)
1252 obj->static_tls = true;
1255 case DT_MIPS_LOCAL_GOTNO:
1256 obj->local_gotno = dynp->d_un.d_val;
1259 case DT_MIPS_SYMTABNO:
1260 obj->symtabno = dynp->d_un.d_val;
1263 case DT_MIPS_GOTSYM:
1264 obj->gotsym = dynp->d_un.d_val;
1267 case DT_MIPS_RLD_MAP:
1268 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1272 #ifdef __powerpc64__
1273 case DT_PPC64_GLINK:
1274 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1279 if (dynp->d_un.d_val & DF_1_NOOPEN)
1280 obj->z_noopen = true;
1281 if (dynp->d_un.d_val & DF_1_ORIGIN)
1282 obj->z_origin = true;
1283 if (dynp->d_un.d_val & DF_1_GLOBAL)
1284 obj->z_global = true;
1285 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1286 obj->bind_now = true;
1287 if (dynp->d_un.d_val & DF_1_NODELETE)
1288 obj->z_nodelete = true;
1289 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1290 obj->z_loadfltr = true;
1291 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1292 obj->z_interpose = true;
1293 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1294 obj->z_nodeflib = true;
1299 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1306 obj->traced = false;
1308 if (plttype == DT_RELA) {
1309 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1311 obj->pltrelasize = obj->pltrelsize;
1312 obj->pltrelsize = 0;
1315 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1316 if (obj->valid_hash_sysv)
1317 obj->dynsymcount = obj->nchains;
1318 else if (obj->valid_hash_gnu) {
1319 obj->dynsymcount = 0;
1320 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1321 if (obj->buckets_gnu[bkt] == 0)
1323 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1326 while ((*hashval++ & 1u) == 0);
1328 obj->dynsymcount += obj->symndx_gnu;
1333 obj_resolve_origin(Obj_Entry *obj)
1336 if (obj->origin_path != NULL)
1338 obj->origin_path = xmalloc(PATH_MAX);
1339 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1343 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1344 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1347 if (obj->z_origin && !obj_resolve_origin(obj))
1350 if (dyn_runpath != NULL) {
1351 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1352 obj->runpath = origin_subst(obj, obj->runpath);
1353 } else if (dyn_rpath != NULL) {
1354 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1355 obj->rpath = origin_subst(obj, obj->rpath);
1357 if (dyn_soname != NULL)
1358 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1362 digest_dynamic(Obj_Entry *obj, int early)
1364 const Elf_Dyn *dyn_rpath;
1365 const Elf_Dyn *dyn_soname;
1366 const Elf_Dyn *dyn_runpath;
1368 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1369 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1373 * Process a shared object's program header. This is used only for the
1374 * main program, when the kernel has already loaded the main program
1375 * into memory before calling the dynamic linker. It creates and
1376 * returns an Obj_Entry structure.
1379 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1382 const Elf_Phdr *phlimit = phdr + phnum;
1384 Elf_Addr note_start, note_end;
1388 for (ph = phdr; ph < phlimit; ph++) {
1389 if (ph->p_type != PT_PHDR)
1393 obj->phsize = ph->p_memsz;
1394 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1398 obj->stack_flags = PF_X | PF_R | PF_W;
1400 for (ph = phdr; ph < phlimit; ph++) {
1401 switch (ph->p_type) {
1404 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1408 if (nsegs == 0) { /* First load segment */
1409 obj->vaddrbase = trunc_page(ph->p_vaddr);
1410 obj->mapbase = obj->vaddrbase + obj->relocbase;
1411 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1413 } else { /* Last load segment */
1414 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1421 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1426 obj->tlssize = ph->p_memsz;
1427 obj->tlsalign = ph->p_align;
1428 obj->tlsinitsize = ph->p_filesz;
1429 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1433 obj->stack_flags = ph->p_flags;
1437 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1438 obj->relro_size = round_page(ph->p_memsz);
1442 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1443 note_end = note_start + ph->p_filesz;
1444 digest_notes(obj, note_start, note_end);
1449 _rtld_error("%s: too few PT_LOAD segments", path);
1458 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1460 const Elf_Note *note;
1461 const char *note_name;
1464 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1465 note = (const Elf_Note *)((const char *)(note + 1) +
1466 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1467 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1468 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1469 note->n_descsz != sizeof(int32_t))
1471 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1472 note->n_type != NT_FREEBSD_NOINIT_TAG)
1474 note_name = (const char *)(note + 1);
1475 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1476 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1478 switch (note->n_type) {
1479 case NT_FREEBSD_ABI_TAG:
1480 /* FreeBSD osrel note */
1481 p = (uintptr_t)(note + 1);
1482 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1483 obj->osrel = *(const int32_t *)(p);
1484 dbg("note osrel %d", obj->osrel);
1486 case NT_FREEBSD_NOINIT_TAG:
1487 /* FreeBSD 'crt does not call init' note */
1488 obj->crt_no_init = true;
1489 dbg("note crt_no_init");
1496 dlcheck(void *handle)
1500 TAILQ_FOREACH(obj, &obj_list, next) {
1501 if (obj == (Obj_Entry *) handle)
1505 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1506 _rtld_error("Invalid shared object handle %p", handle);
1513 * If the given object is already in the donelist, return true. Otherwise
1514 * add the object to the list and return false.
1517 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1521 for (i = 0; i < dlp->num_used; i++)
1522 if (dlp->objs[i] == obj)
1525 * Our donelist allocation should always be sufficient. But if
1526 * our threads locking isn't working properly, more shared objects
1527 * could have been loaded since we allocated the list. That should
1528 * never happen, but we'll handle it properly just in case it does.
1530 if (dlp->num_used < dlp->num_alloc)
1531 dlp->objs[dlp->num_used++] = obj;
1536 * Hash function for symbol table lookup. Don't even think about changing
1537 * this. It is specified by the System V ABI.
1540 elf_hash(const char *name)
1542 const unsigned char *p = (const unsigned char *) name;
1543 unsigned long h = 0;
1546 while (*p != '\0') {
1547 h = (h << 4) + *p++;
1548 if ((g = h & 0xf0000000) != 0)
1556 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1557 * unsigned in case it's implemented with a wider type.
1560 gnu_hash(const char *s)
1566 for (c = *s; c != '\0'; c = *++s)
1568 return (h & 0xffffffff);
1573 * Find the library with the given name, and return its full pathname.
1574 * The returned string is dynamically allocated. Generates an error
1575 * message and returns NULL if the library cannot be found.
1577 * If the second argument is non-NULL, then it refers to an already-
1578 * loaded shared object, whose library search path will be searched.
1580 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1581 * descriptor (which is close-on-exec) will be passed out via the third
1584 * The search order is:
1585 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1586 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1588 * DT_RUNPATH in the referencing file
1589 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1591 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1593 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1596 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1598 char *name, *pathname, *refobj_path;
1599 bool nodeflib, objgiven;
1601 objgiven = refobj != NULL;
1603 if (libmap_disable || !objgiven ||
1604 (name = lm_find(refobj->path, xname)) == NULL)
1605 name = (char *)xname;
1607 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1608 if (name[0] != '/' && !trust) {
1609 _rtld_error("Absolute pathname required "
1610 "for shared object \"%s\"", name);
1613 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1614 __DECONST(char *, name)));
1617 dbg(" Searching for \"%s\"", name);
1618 refobj_path = objgiven ? refobj->path : NULL;
1621 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1622 * back to pre-conforming behaviour if user requested so with
1623 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1626 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1627 pathname = search_library_path(name, ld_library_path,
1629 if (pathname != NULL)
1631 if (refobj != NULL) {
1632 pathname = search_library_path(name, refobj->rpath,
1634 if (pathname != NULL)
1637 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1638 if (pathname != NULL)
1640 pathname = search_library_path(name, gethints(false),
1642 if (pathname != NULL)
1644 pathname = search_library_path(name, ld_standard_library_path,
1646 if (pathname != NULL)
1649 nodeflib = objgiven ? refobj->z_nodeflib : false;
1651 pathname = search_library_path(name, refobj->rpath,
1653 if (pathname != NULL)
1656 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1657 pathname = search_library_path(name, obj_main->rpath,
1659 if (pathname != NULL)
1662 pathname = search_library_path(name, ld_library_path,
1664 if (pathname != NULL)
1667 pathname = search_library_path(name, refobj->runpath,
1669 if (pathname != NULL)
1672 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1673 if (pathname != NULL)
1675 pathname = search_library_path(name, gethints(nodeflib),
1677 if (pathname != NULL)
1679 if (objgiven && !nodeflib) {
1680 pathname = search_library_path(name,
1681 ld_standard_library_path, refobj_path, fdp);
1682 if (pathname != NULL)
1687 if (objgiven && refobj->path != NULL) {
1688 _rtld_error("Shared object \"%s\" not found, "
1689 "required by \"%s\"", name, basename(refobj->path));
1691 _rtld_error("Shared object \"%s\" not found", name);
1697 * Given a symbol number in a referencing object, find the corresponding
1698 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1699 * no definition was found. Returns a pointer to the Obj_Entry of the
1700 * defining object via the reference parameter DEFOBJ_OUT.
1703 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1704 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1705 RtldLockState *lockstate)
1709 const Obj_Entry *defobj;
1710 const Ver_Entry *ve;
1716 * If we have already found this symbol, get the information from
1719 if (symnum >= refobj->dynsymcount)
1720 return NULL; /* Bad object */
1721 if (cache != NULL && cache[symnum].sym != NULL) {
1722 *defobj_out = cache[symnum].obj;
1723 return cache[symnum].sym;
1726 ref = refobj->symtab + symnum;
1727 name = refobj->strtab + ref->st_name;
1733 * We don't have to do a full scale lookup if the symbol is local.
1734 * We know it will bind to the instance in this load module; to
1735 * which we already have a pointer (ie ref). By not doing a lookup,
1736 * we not only improve performance, but it also avoids unresolvable
1737 * symbols when local symbols are not in the hash table. This has
1738 * been seen with the ia64 toolchain.
1740 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1741 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1742 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1745 symlook_init(&req, name);
1747 ve = req.ventry = fetch_ventry(refobj, symnum);
1748 req.lockstate = lockstate;
1749 res = symlook_default(&req, refobj);
1752 defobj = req.defobj_out;
1760 * If we found no definition and the reference is weak, treat the
1761 * symbol as having the value zero.
1763 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1769 *defobj_out = defobj;
1770 /* Record the information in the cache to avoid subsequent lookups. */
1771 if (cache != NULL) {
1772 cache[symnum].sym = def;
1773 cache[symnum].obj = defobj;
1776 if (refobj != &obj_rtld)
1777 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1778 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1784 * Return the search path from the ldconfig hints file, reading it if
1785 * necessary. If nostdlib is true, then the default search paths are
1786 * not added to result.
1788 * Returns NULL if there are problems with the hints file,
1789 * or if the search path there is empty.
1792 gethints(bool nostdlib)
1794 static char *hints, *filtered_path;
1795 static struct elfhints_hdr hdr;
1796 struct fill_search_info_args sargs, hargs;
1797 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1798 struct dl_serpath *SLPpath, *hintpath;
1800 struct stat hint_stat;
1801 unsigned int SLPndx, hintndx, fndx, fcount;
1807 /* First call, read the hints file */
1808 if (hints == NULL) {
1809 /* Keep from trying again in case the hints file is bad. */
1812 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1816 * Check of hdr.dirlistlen value against type limit
1817 * intends to pacify static analyzers. Further
1818 * paranoia leads to checks that dirlist is fully
1819 * contained in the file range.
1821 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1822 hdr.magic != ELFHINTS_MAGIC ||
1823 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1824 fstat(fd, &hint_stat) == -1) {
1831 if (dl + hdr.dirlist < dl)
1834 if (dl + hdr.dirlistlen < dl)
1836 dl += hdr.dirlistlen;
1837 if (dl > hint_stat.st_size)
1839 p = xmalloc(hdr.dirlistlen + 1);
1840 if (pread(fd, p, hdr.dirlistlen + 1,
1841 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1842 p[hdr.dirlistlen] != '\0') {
1851 * If caller agreed to receive list which includes the default
1852 * paths, we are done. Otherwise, if we still did not
1853 * calculated filtered result, do it now.
1856 return (hints[0] != '\0' ? hints : NULL);
1857 if (filtered_path != NULL)
1861 * Obtain the list of all configured search paths, and the
1862 * list of the default paths.
1864 * First estimate the size of the results.
1866 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1868 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1871 sargs.request = RTLD_DI_SERINFOSIZE;
1872 sargs.serinfo = &smeta;
1873 hargs.request = RTLD_DI_SERINFOSIZE;
1874 hargs.serinfo = &hmeta;
1876 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1878 path_enumerate(hints, fill_search_info, NULL, &hargs);
1880 SLPinfo = xmalloc(smeta.dls_size);
1881 hintinfo = xmalloc(hmeta.dls_size);
1884 * Next fetch both sets of paths.
1886 sargs.request = RTLD_DI_SERINFO;
1887 sargs.serinfo = SLPinfo;
1888 sargs.serpath = &SLPinfo->dls_serpath[0];
1889 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1891 hargs.request = RTLD_DI_SERINFO;
1892 hargs.serinfo = hintinfo;
1893 hargs.serpath = &hintinfo->dls_serpath[0];
1894 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1896 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1898 path_enumerate(hints, fill_search_info, NULL, &hargs);
1901 * Now calculate the difference between two sets, by excluding
1902 * standard paths from the full set.
1906 filtered_path = xmalloc(hdr.dirlistlen + 1);
1907 hintpath = &hintinfo->dls_serpath[0];
1908 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1910 SLPpath = &SLPinfo->dls_serpath[0];
1912 * Check each standard path against current.
1914 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1915 /* matched, skip the path */
1916 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1924 * Not matched against any standard path, add the path
1925 * to result. Separate consequtive paths with ':'.
1928 filtered_path[fndx] = ':';
1932 flen = strlen(hintpath->dls_name);
1933 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1936 filtered_path[fndx] = '\0';
1942 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1946 init_dag(Obj_Entry *root)
1948 const Needed_Entry *needed;
1949 const Objlist_Entry *elm;
1952 if (root->dag_inited)
1954 donelist_init(&donelist);
1956 /* Root object belongs to own DAG. */
1957 objlist_push_tail(&root->dldags, root);
1958 objlist_push_tail(&root->dagmembers, root);
1959 donelist_check(&donelist, root);
1962 * Add dependencies of root object to DAG in breadth order
1963 * by exploiting the fact that each new object get added
1964 * to the tail of the dagmembers list.
1966 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1967 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1968 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1970 objlist_push_tail(&needed->obj->dldags, root);
1971 objlist_push_tail(&root->dagmembers, needed->obj);
1974 root->dag_inited = true;
1978 init_marker(Obj_Entry *marker)
1981 bzero(marker, sizeof(*marker));
1982 marker->marker = true;
1986 globallist_curr(const Obj_Entry *obj)
1993 return (__DECONST(Obj_Entry *, obj));
1994 obj = TAILQ_PREV(obj, obj_entry_q, next);
1999 globallist_next(const Obj_Entry *obj)
2003 obj = TAILQ_NEXT(obj, next);
2007 return (__DECONST(Obj_Entry *, obj));
2011 /* Prevent the object from being unmapped while the bind lock is dropped. */
2013 hold_object(Obj_Entry *obj)
2020 unhold_object(Obj_Entry *obj)
2023 assert(obj->holdcount > 0);
2024 if (--obj->holdcount == 0 && obj->unholdfree)
2025 release_object(obj);
2029 process_z(Obj_Entry *root)
2031 const Objlist_Entry *elm;
2035 * Walk over object DAG and process every dependent object
2036 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2037 * to grow their own DAG.
2039 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2040 * symlook_global() to work.
2042 * For DF_1_NODELETE, the DAG should have its reference upped.
2044 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2048 if (obj->z_nodelete && !obj->ref_nodel) {
2049 dbg("obj %s -z nodelete", obj->path);
2052 obj->ref_nodel = true;
2054 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2055 dbg("obj %s -z global", obj->path);
2056 objlist_push_tail(&list_global, obj);
2062 * Initialize the dynamic linker. The argument is the address at which
2063 * the dynamic linker has been mapped into memory. The primary task of
2064 * this function is to relocate the dynamic linker.
2067 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2069 Obj_Entry objtmp; /* Temporary rtld object */
2070 const Elf_Ehdr *ehdr;
2071 const Elf_Dyn *dyn_rpath;
2072 const Elf_Dyn *dyn_soname;
2073 const Elf_Dyn *dyn_runpath;
2075 #ifdef RTLD_INIT_PAGESIZES_EARLY
2076 /* The page size is required by the dynamic memory allocator. */
2077 init_pagesizes(aux_info);
2081 * Conjure up an Obj_Entry structure for the dynamic linker.
2083 * The "path" member can't be initialized yet because string constants
2084 * cannot yet be accessed. Below we will set it correctly.
2086 memset(&objtmp, 0, sizeof(objtmp));
2089 objtmp.mapbase = mapbase;
2091 objtmp.relocbase = mapbase;
2094 objtmp.dynamic = rtld_dynamic(&objtmp);
2095 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2096 assert(objtmp.needed == NULL);
2097 #if !defined(__mips__)
2098 /* MIPS has a bogus DT_TEXTREL. */
2099 assert(!objtmp.textrel);
2102 * Temporarily put the dynamic linker entry into the object list, so
2103 * that symbols can be found.
2105 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2107 ehdr = (Elf_Ehdr *)mapbase;
2108 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2109 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2111 /* Initialize the object list. */
2112 TAILQ_INIT(&obj_list);
2114 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2115 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2117 #ifndef RTLD_INIT_PAGESIZES_EARLY
2118 /* The page size is required by the dynamic memory allocator. */
2119 init_pagesizes(aux_info);
2122 if (aux_info[AT_OSRELDATE] != NULL)
2123 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2125 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2127 /* Replace the path with a dynamically allocated copy. */
2128 obj_rtld.path = xstrdup(ld_path_rtld);
2130 r_debug.r_brk = r_debug_state;
2131 r_debug.r_state = RT_CONSISTENT;
2135 * Retrieve the array of supported page sizes. The kernel provides the page
2136 * sizes in increasing order.
2139 init_pagesizes(Elf_Auxinfo **aux_info)
2141 static size_t psa[MAXPAGESIZES];
2145 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2147 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2148 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2151 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2154 /* As a fallback, retrieve the base page size. */
2155 size = sizeof(psa[0]);
2156 if (aux_info[AT_PAGESZ] != NULL) {
2157 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2161 mib[1] = HW_PAGESIZE;
2165 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2166 _rtld_error("sysctl for hw.pagesize(s) failed");
2172 npagesizes = size / sizeof(pagesizes[0]);
2173 /* Discard any invalid entries at the end of the array. */
2174 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2179 * Add the init functions from a needed object list (and its recursive
2180 * needed objects) to "list". This is not used directly; it is a helper
2181 * function for initlist_add_objects(). The write lock must be held
2182 * when this function is called.
2185 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2187 /* Recursively process the successor needed objects. */
2188 if (needed->next != NULL)
2189 initlist_add_neededs(needed->next, list);
2191 /* Process the current needed object. */
2192 if (needed->obj != NULL)
2193 initlist_add_objects(needed->obj, needed->obj, list);
2197 * Scan all of the DAGs rooted in the range of objects from "obj" to
2198 * "tail" and add their init functions to "list". This recurses over
2199 * the DAGs and ensure the proper init ordering such that each object's
2200 * needed libraries are initialized before the object itself. At the
2201 * same time, this function adds the objects to the global finalization
2202 * list "list_fini" in the opposite order. The write lock must be
2203 * held when this function is called.
2206 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2210 if (obj->init_scanned || obj->init_done)
2212 obj->init_scanned = true;
2214 /* Recursively process the successor objects. */
2215 nobj = globallist_next(obj);
2216 if (nobj != NULL && obj != tail)
2217 initlist_add_objects(nobj, tail, list);
2219 /* Recursively process the needed objects. */
2220 if (obj->needed != NULL)
2221 initlist_add_neededs(obj->needed, list);
2222 if (obj->needed_filtees != NULL)
2223 initlist_add_neededs(obj->needed_filtees, list);
2224 if (obj->needed_aux_filtees != NULL)
2225 initlist_add_neededs(obj->needed_aux_filtees, list);
2227 /* Add the object to the init list. */
2228 objlist_push_tail(list, obj);
2230 /* Add the object to the global fini list in the reverse order. */
2231 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2232 && !obj->on_fini_list) {
2233 objlist_push_head(&list_fini, obj);
2234 obj->on_fini_list = true;
2239 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2243 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2245 Needed_Entry *needed, *needed1;
2247 for (needed = n; needed != NULL; needed = needed->next) {
2248 if (needed->obj != NULL) {
2249 dlclose_locked(needed->obj, lockstate);
2253 for (needed = n; needed != NULL; needed = needed1) {
2254 needed1 = needed->next;
2260 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2263 free_needed_filtees(obj->needed_filtees, lockstate);
2264 obj->needed_filtees = NULL;
2265 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2266 obj->needed_aux_filtees = NULL;
2267 obj->filtees_loaded = false;
2271 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2272 RtldLockState *lockstate)
2275 for (; needed != NULL; needed = needed->next) {
2276 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2277 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2278 RTLD_LOCAL, lockstate);
2283 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2286 lock_restart_for_upgrade(lockstate);
2287 if (!obj->filtees_loaded) {
2288 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2289 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2290 obj->filtees_loaded = true;
2295 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2299 for (; needed != NULL; needed = needed->next) {
2300 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2301 flags & ~RTLD_LO_NOLOAD);
2302 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2309 * Given a shared object, traverse its list of needed objects, and load
2310 * each of them. Returns 0 on success. Generates an error message and
2311 * returns -1 on failure.
2314 load_needed_objects(Obj_Entry *first, int flags)
2318 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2321 if (process_needed(obj, obj->needed, flags) == -1)
2328 load_preload_objects(void)
2330 char *p = ld_preload;
2332 static const char delim[] = " \t:;";
2337 p += strspn(p, delim);
2338 while (*p != '\0') {
2339 size_t len = strcspn(p, delim);
2344 obj = load_object(p, -1, NULL, 0);
2346 return -1; /* XXX - cleanup */
2347 obj->z_interpose = true;
2350 p += strspn(p, delim);
2352 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2357 printable_path(const char *path)
2360 return (path == NULL ? "<unknown>" : path);
2364 * Load a shared object into memory, if it is not already loaded. The
2365 * object may be specified by name or by user-supplied file descriptor
2366 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2369 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2373 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2382 TAILQ_FOREACH(obj, &obj_list, next) {
2383 if (obj->marker || obj->doomed)
2385 if (object_match_name(obj, name))
2389 path = find_library(name, refobj, &fd);
2397 * search_library_pathfds() opens a fresh file descriptor for the
2398 * library, so there is no need to dup().
2400 } else if (fd_u == -1) {
2402 * If we didn't find a match by pathname, or the name is not
2403 * supplied, open the file and check again by device and inode.
2404 * This avoids false mismatches caused by multiple links or ".."
2407 * To avoid a race, we open the file and use fstat() rather than
2410 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2411 _rtld_error("Cannot open \"%s\"", path);
2416 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2418 _rtld_error("Cannot dup fd");
2423 if (fstat(fd, &sb) == -1) {
2424 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2429 TAILQ_FOREACH(obj, &obj_list, next) {
2430 if (obj->marker || obj->doomed)
2432 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2435 if (obj != NULL && name != NULL) {
2436 object_add_name(obj, name);
2441 if (flags & RTLD_LO_NOLOAD) {
2447 /* First use of this object, so we must map it in */
2448 obj = do_load_object(fd, name, path, &sb, flags);
2457 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2464 * but first, make sure that environment variables haven't been
2465 * used to circumvent the noexec flag on a filesystem.
2467 if (dangerous_ld_env) {
2468 if (fstatfs(fd, &fs) != 0) {
2469 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2472 if (fs.f_flags & MNT_NOEXEC) {
2473 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2477 dbg("loading \"%s\"", printable_path(path));
2478 obj = map_object(fd, printable_path(path), sbp);
2483 * If DT_SONAME is present in the object, digest_dynamic2 already
2484 * added it to the object names.
2487 object_add_name(obj, name);
2489 digest_dynamic(obj, 0);
2490 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2491 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2492 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2494 dbg("refusing to load non-loadable \"%s\"", obj->path);
2495 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2496 munmap(obj->mapbase, obj->mapsize);
2501 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2502 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2505 linkmap_add(obj); /* for GDB & dlinfo() */
2506 max_stack_flags |= obj->stack_flags;
2508 dbg(" %p .. %p: %s", obj->mapbase,
2509 obj->mapbase + obj->mapsize - 1, obj->path);
2511 dbg(" WARNING: %s has impure text", obj->path);
2512 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2519 obj_from_addr(const void *addr)
2523 TAILQ_FOREACH(obj, &obj_list, next) {
2526 if (addr < (void *) obj->mapbase)
2528 if (addr < (void *) (obj->mapbase + obj->mapsize))
2537 Elf_Addr *preinit_addr;
2540 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2541 if (preinit_addr == NULL)
2544 for (index = 0; index < obj_main->preinit_array_num; index++) {
2545 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2546 dbg("calling preinit function for %s at %p", obj_main->path,
2547 (void *)preinit_addr[index]);
2548 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2549 0, 0, obj_main->path);
2550 call_init_pointer(obj_main, preinit_addr[index]);
2556 * Call the finalization functions for each of the objects in "list"
2557 * belonging to the DAG of "root" and referenced once. If NULL "root"
2558 * is specified, every finalization function will be called regardless
2559 * of the reference count and the list elements won't be freed. All of
2560 * the objects are expected to have non-NULL fini functions.
2563 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2567 Elf_Addr *fini_addr;
2570 assert(root == NULL || root->refcount == 1);
2573 root->doomed = true;
2576 * Preserve the current error message since a fini function might
2577 * call into the dynamic linker and overwrite it.
2579 saved_msg = errmsg_save();
2581 STAILQ_FOREACH(elm, list, link) {
2582 if (root != NULL && (elm->obj->refcount != 1 ||
2583 objlist_find(&root->dagmembers, elm->obj) == NULL))
2585 /* Remove object from fini list to prevent recursive invocation. */
2586 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2587 /* Ensure that new references cannot be acquired. */
2588 elm->obj->doomed = true;
2590 hold_object(elm->obj);
2591 lock_release(rtld_bind_lock, lockstate);
2593 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2594 * When this happens, DT_FINI_ARRAY is processed first.
2596 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2597 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2598 for (index = elm->obj->fini_array_num - 1; index >= 0;
2600 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2601 dbg("calling fini function for %s at %p",
2602 elm->obj->path, (void *)fini_addr[index]);
2603 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2604 (void *)fini_addr[index], 0, 0, elm->obj->path);
2605 call_initfini_pointer(elm->obj, fini_addr[index]);
2609 if (elm->obj->fini != (Elf_Addr)NULL) {
2610 dbg("calling fini function for %s at %p", elm->obj->path,
2611 (void *)elm->obj->fini);
2612 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2613 0, 0, elm->obj->path);
2614 call_initfini_pointer(elm->obj, elm->obj->fini);
2616 wlock_acquire(rtld_bind_lock, lockstate);
2617 unhold_object(elm->obj);
2618 /* No need to free anything if process is going down. */
2622 * We must restart the list traversal after every fini call
2623 * because a dlclose() call from the fini function or from
2624 * another thread might have modified the reference counts.
2628 } while (elm != NULL);
2629 errmsg_restore(saved_msg);
2633 * Call the initialization functions for each of the objects in
2634 * "list". All of the objects are expected to have non-NULL init
2638 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2643 Elf_Addr *init_addr;
2647 * Clean init_scanned flag so that objects can be rechecked and
2648 * possibly initialized earlier if any of vectors called below
2649 * cause the change by using dlopen.
2651 TAILQ_FOREACH(obj, &obj_list, next) {
2654 obj->init_scanned = false;
2658 * Preserve the current error message since an init function might
2659 * call into the dynamic linker and overwrite it.
2661 saved_msg = errmsg_save();
2662 STAILQ_FOREACH(elm, list, link) {
2663 if (elm->obj->init_done) /* Initialized early. */
2666 * Race: other thread might try to use this object before current
2667 * one completes the initialization. Not much can be done here
2668 * without better locking.
2670 elm->obj->init_done = true;
2671 hold_object(elm->obj);
2672 lock_release(rtld_bind_lock, lockstate);
2675 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2676 * When this happens, DT_INIT is processed first.
2678 if (elm->obj->init != (Elf_Addr)NULL) {
2679 dbg("calling init function for %s at %p", elm->obj->path,
2680 (void *)elm->obj->init);
2681 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2682 0, 0, elm->obj->path);
2683 call_initfini_pointer(elm->obj, elm->obj->init);
2685 init_addr = (Elf_Addr *)elm->obj->init_array;
2686 if (init_addr != NULL) {
2687 for (index = 0; index < elm->obj->init_array_num; index++) {
2688 if (init_addr[index] != 0 && init_addr[index] != 1) {
2689 dbg("calling init function for %s at %p", elm->obj->path,
2690 (void *)init_addr[index]);
2691 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2692 (void *)init_addr[index], 0, 0, elm->obj->path);
2693 call_init_pointer(elm->obj, init_addr[index]);
2697 wlock_acquire(rtld_bind_lock, lockstate);
2698 unhold_object(elm->obj);
2700 errmsg_restore(saved_msg);
2704 objlist_clear(Objlist *list)
2708 while (!STAILQ_EMPTY(list)) {
2709 elm = STAILQ_FIRST(list);
2710 STAILQ_REMOVE_HEAD(list, link);
2715 static Objlist_Entry *
2716 objlist_find(Objlist *list, const Obj_Entry *obj)
2720 STAILQ_FOREACH(elm, list, link)
2721 if (elm->obj == obj)
2727 objlist_init(Objlist *list)
2733 objlist_push_head(Objlist *list, Obj_Entry *obj)
2737 elm = NEW(Objlist_Entry);
2739 STAILQ_INSERT_HEAD(list, elm, link);
2743 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2747 elm = NEW(Objlist_Entry);
2749 STAILQ_INSERT_TAIL(list, elm, link);
2753 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2755 Objlist_Entry *elm, *listelm;
2757 STAILQ_FOREACH(listelm, list, link) {
2758 if (listelm->obj == listobj)
2761 elm = NEW(Objlist_Entry);
2763 if (listelm != NULL)
2764 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2766 STAILQ_INSERT_TAIL(list, elm, link);
2770 objlist_remove(Objlist *list, Obj_Entry *obj)
2774 if ((elm = objlist_find(list, obj)) != NULL) {
2775 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2781 * Relocate dag rooted in the specified object.
2782 * Returns 0 on success, or -1 on failure.
2786 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2787 int flags, RtldLockState *lockstate)
2793 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2794 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2803 * Prepare for, or clean after, relocating an object marked with
2804 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2805 * segments are remapped read-write. After relocations are done, the
2806 * segment's permissions are returned back to the modes specified in
2807 * the phdrs. If any relocation happened, or always for wired
2808 * program, COW is triggered.
2811 reloc_textrel_prot(Obj_Entry *obj, bool before)
2818 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2820 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2822 base = obj->relocbase + trunc_page(ph->p_vaddr);
2823 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2824 trunc_page(ph->p_vaddr);
2825 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2826 if (mprotect(base, sz, prot) == -1) {
2827 _rtld_error("%s: Cannot write-%sable text segment: %s",
2828 obj->path, before ? "en" : "dis",
2829 rtld_strerror(errno));
2837 * Relocate single object.
2838 * Returns 0 on success, or -1 on failure.
2841 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2842 int flags, RtldLockState *lockstate)
2847 obj->relocated = true;
2849 dbg("relocating \"%s\"", obj->path);
2851 if (obj->symtab == NULL || obj->strtab == NULL ||
2852 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2853 _rtld_error("%s: Shared object has no run-time symbol table",
2858 /* There are relocations to the write-protected text segment. */
2859 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2862 /* Process the non-PLT non-IFUNC relocations. */
2863 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2866 /* Re-protected the text segment. */
2867 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2870 /* Set the special PLT or GOT entries. */
2873 /* Process the PLT relocations. */
2874 if (reloc_plt(obj) == -1)
2876 /* Relocate the jump slots if we are doing immediate binding. */
2877 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
2881 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2885 * Set up the magic number and version in the Obj_Entry. These
2886 * were checked in the crt1.o from the original ElfKit, so we
2887 * set them for backward compatibility.
2889 obj->magic = RTLD_MAGIC;
2890 obj->version = RTLD_VERSION;
2896 * Relocate newly-loaded shared objects. The argument is a pointer to
2897 * the Obj_Entry for the first such object. All objects from the first
2898 * to the end of the list of objects are relocated. Returns 0 on success,
2902 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2903 int flags, RtldLockState *lockstate)
2908 for (error = 0, obj = first; obj != NULL;
2909 obj = TAILQ_NEXT(obj, next)) {
2912 error = relocate_object(obj, bind_now, rtldobj, flags,
2921 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2922 * referencing STT_GNU_IFUNC symbols is postponed till the other
2923 * relocations are done. The indirect functions specified as
2924 * ifunc are allowed to call other symbols, so we need to have
2925 * objects relocated before asking for resolution from indirects.
2927 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2928 * instead of the usual lazy handling of PLT slots. It is
2929 * consistent with how GNU does it.
2932 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2933 RtldLockState *lockstate)
2936 if (obj->ifuncs_resolved)
2938 obj->ifuncs_resolved = true;
2939 if (!obj->irelative && !((obj->bind_now || bind_now) && obj->gnu_ifunc))
2941 if (obj_disable_relro(obj) == -1 ||
2942 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
2943 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2944 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
2945 obj_enforce_relro(obj) == -1)
2951 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2952 RtldLockState *lockstate)
2957 STAILQ_FOREACH(elm, list, link) {
2961 if (resolve_object_ifunc(obj, bind_now, flags,
2969 * Cleanup procedure. It will be called (by the atexit mechanism) just
2970 * before the process exits.
2975 RtldLockState lockstate;
2977 wlock_acquire(rtld_bind_lock, &lockstate);
2979 objlist_call_fini(&list_fini, NULL, &lockstate);
2980 /* No need to remove the items from the list, since we are exiting. */
2981 if (!libmap_disable)
2983 lock_release(rtld_bind_lock, &lockstate);
2987 * Iterate over a search path, translate each element, and invoke the
2988 * callback on the result.
2991 path_enumerate(const char *path, path_enum_proc callback,
2992 const char *refobj_path, void *arg)
2998 path += strspn(path, ":;");
2999 while (*path != '\0') {
3003 len = strcspn(path, ":;");
3004 trans = lm_findn(refobj_path, path, len);
3006 res = callback(trans, strlen(trans), arg);
3008 res = callback(path, len, arg);
3014 path += strspn(path, ":;");
3020 struct try_library_args {
3029 try_library_path(const char *dir, size_t dirlen, void *param)
3031 struct try_library_args *arg;
3035 if (*dir == '/' || trust) {
3038 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3041 pathname = arg->buffer;
3042 strncpy(pathname, dir, dirlen);
3043 pathname[dirlen] = '/';
3044 strcpy(pathname + dirlen + 1, arg->name);
3046 dbg(" Trying \"%s\"", pathname);
3047 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3049 dbg(" Opened \"%s\", fd %d", pathname, fd);
3050 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3051 strcpy(pathname, arg->buffer);
3055 dbg(" Failed to open \"%s\": %s",
3056 pathname, rtld_strerror(errno));
3063 search_library_path(const char *name, const char *path,
3064 const char *refobj_path, int *fdp)
3067 struct try_library_args arg;
3073 arg.namelen = strlen(name);
3074 arg.buffer = xmalloc(PATH_MAX);
3075 arg.buflen = PATH_MAX;
3078 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3088 * Finds the library with the given name using the directory descriptors
3089 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3091 * Returns a freshly-opened close-on-exec file descriptor for the library,
3092 * or -1 if the library cannot be found.
3095 search_library_pathfds(const char *name, const char *path, int *fdp)
3097 char *envcopy, *fdstr, *found, *last_token;
3101 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3103 /* Don't load from user-specified libdirs into setuid binaries. */
3107 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3111 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3112 if (name[0] == '/') {
3113 dbg("Absolute path (%s) passed to %s", name, __func__);
3118 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3119 * copy of the path, as strtok_r rewrites separator tokens
3123 envcopy = xstrdup(path);
3124 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3125 fdstr = strtok_r(NULL, ":", &last_token)) {
3126 dirfd = parse_integer(fdstr);
3128 _rtld_error("failed to parse directory FD: '%s'",
3132 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3135 len = strlen(fdstr) + strlen(name) + 3;
3136 found = xmalloc(len);
3137 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3138 _rtld_error("error generating '%d/%s'",
3142 dbg("open('%s') => %d", found, fd);
3153 dlclose(void *handle)
3155 RtldLockState lockstate;
3158 wlock_acquire(rtld_bind_lock, &lockstate);
3159 error = dlclose_locked(handle, &lockstate);
3160 lock_release(rtld_bind_lock, &lockstate);
3165 dlclose_locked(void *handle, RtldLockState *lockstate)
3169 root = dlcheck(handle);
3172 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3175 /* Unreference the object and its dependencies. */
3176 root->dl_refcount--;
3178 if (root->refcount == 1) {
3180 * The object will be no longer referenced, so we must unload it.
3181 * First, call the fini functions.
3183 objlist_call_fini(&list_fini, root, lockstate);
3187 /* Finish cleaning up the newly-unreferenced objects. */
3188 GDB_STATE(RT_DELETE,&root->linkmap);
3189 unload_object(root, lockstate);
3190 GDB_STATE(RT_CONSISTENT,NULL);
3194 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3201 char *msg = error_message;
3202 error_message = NULL;
3207 * This function is deprecated and has no effect.
3210 dllockinit(void *context,
3211 void *(*lock_create)(void *context),
3212 void (*rlock_acquire)(void *lock),
3213 void (*wlock_acquire)(void *lock),
3214 void (*lock_release)(void *lock),
3215 void (*lock_destroy)(void *lock),
3216 void (*context_destroy)(void *context))
3218 static void *cur_context;
3219 static void (*cur_context_destroy)(void *);
3221 /* Just destroy the context from the previous call, if necessary. */
3222 if (cur_context_destroy != NULL)
3223 cur_context_destroy(cur_context);
3224 cur_context = context;
3225 cur_context_destroy = context_destroy;
3229 dlopen(const char *name, int mode)
3232 return (rtld_dlopen(name, -1, mode));
3236 fdlopen(int fd, int mode)
3239 return (rtld_dlopen(NULL, fd, mode));
3243 rtld_dlopen(const char *name, int fd, int mode)
3245 RtldLockState lockstate;
3248 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3249 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3250 if (ld_tracing != NULL) {
3251 rlock_acquire(rtld_bind_lock, &lockstate);
3252 if (sigsetjmp(lockstate.env, 0) != 0)
3253 lock_upgrade(rtld_bind_lock, &lockstate);
3254 environ = (char **)*get_program_var_addr("environ", &lockstate);
3255 lock_release(rtld_bind_lock, &lockstate);
3257 lo_flags = RTLD_LO_DLOPEN;
3258 if (mode & RTLD_NODELETE)
3259 lo_flags |= RTLD_LO_NODELETE;
3260 if (mode & RTLD_NOLOAD)
3261 lo_flags |= RTLD_LO_NOLOAD;
3262 if (ld_tracing != NULL)
3263 lo_flags |= RTLD_LO_TRACE;
3265 return (dlopen_object(name, fd, obj_main, lo_flags,
3266 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3270 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3275 if (obj->refcount == 0)
3276 unload_object(obj, lockstate);
3280 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3281 int mode, RtldLockState *lockstate)
3283 Obj_Entry *old_obj_tail;
3286 RtldLockState mlockstate;
3289 objlist_init(&initlist);
3291 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3292 wlock_acquire(rtld_bind_lock, &mlockstate);
3293 lockstate = &mlockstate;
3295 GDB_STATE(RT_ADD,NULL);
3297 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3299 if (name == NULL && fd == -1) {
3303 obj = load_object(name, fd, refobj, lo_flags);
3308 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3309 objlist_push_tail(&list_global, obj);
3310 if (globallist_next(old_obj_tail) != NULL) {
3311 /* We loaded something new. */
3312 assert(globallist_next(old_obj_tail) == obj);
3314 if ((lo_flags & RTLD_LO_EARLY) == 0 && obj->static_tls &&
3315 !allocate_tls_offset(obj)) {
3316 _rtld_error("%s: No space available "
3317 "for static Thread Local Storage", obj->path);
3321 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3326 result = rtld_verify_versions(&obj->dagmembers);
3327 if (result != -1 && ld_tracing)
3329 if (result == -1 || relocate_object_dag(obj,
3330 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3331 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3333 dlopen_cleanup(obj, lockstate);
3335 } else if (lo_flags & RTLD_LO_EARLY) {
3337 * Do not call the init functions for early loaded
3338 * filtees. The image is still not initialized enough
3341 * Our object is found by the global object list and
3342 * will be ordered among all init calls done right
3343 * before transferring control to main.
3346 /* Make list of init functions to call. */
3347 initlist_add_objects(obj, obj, &initlist);
3350 * Process all no_delete or global objects here, given
3351 * them own DAGs to prevent their dependencies from being
3352 * unloaded. This has to be done after we have loaded all
3353 * of the dependencies, so that we do not miss any.
3359 * Bump the reference counts for objects on this DAG. If
3360 * this is the first dlopen() call for the object that was
3361 * already loaded as a dependency, initialize the dag
3367 if ((lo_flags & RTLD_LO_TRACE) != 0)
3370 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3371 obj->z_nodelete) && !obj->ref_nodel) {
3372 dbg("obj %s nodelete", obj->path);
3374 obj->z_nodelete = obj->ref_nodel = true;
3378 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3380 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3382 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3383 map_stacks_exec(lockstate);
3385 distribute_static_tls(&initlist, lockstate);
3388 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3389 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3391 objlist_clear(&initlist);
3392 dlopen_cleanup(obj, lockstate);
3393 if (lockstate == &mlockstate)
3394 lock_release(rtld_bind_lock, lockstate);
3398 if (!(lo_flags & RTLD_LO_EARLY)) {
3399 /* Call the init functions. */
3400 objlist_call_init(&initlist, lockstate);
3402 objlist_clear(&initlist);
3403 if (lockstate == &mlockstate)
3404 lock_release(rtld_bind_lock, lockstate);
3407 trace_loaded_objects(obj);
3408 if (lockstate == &mlockstate)
3409 lock_release(rtld_bind_lock, lockstate);
3414 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3418 const Obj_Entry *obj, *defobj;
3421 RtldLockState lockstate;
3428 symlook_init(&req, name);
3430 req.flags = flags | SYMLOOK_IN_PLT;
3431 req.lockstate = &lockstate;
3433 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3434 rlock_acquire(rtld_bind_lock, &lockstate);
3435 if (sigsetjmp(lockstate.env, 0) != 0)
3436 lock_upgrade(rtld_bind_lock, &lockstate);
3437 if (handle == NULL || handle == RTLD_NEXT ||
3438 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3440 if ((obj = obj_from_addr(retaddr)) == NULL) {
3441 _rtld_error("Cannot determine caller's shared object");
3442 lock_release(rtld_bind_lock, &lockstate);
3443 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3446 if (handle == NULL) { /* Just the caller's shared object. */
3447 res = symlook_obj(&req, obj);
3450 defobj = req.defobj_out;
3452 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3453 handle == RTLD_SELF) { /* ... caller included */
3454 if (handle == RTLD_NEXT)
3455 obj = globallist_next(obj);
3456 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3459 res = symlook_obj(&req, obj);
3462 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3464 defobj = req.defobj_out;
3465 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3471 * Search the dynamic linker itself, and possibly resolve the
3472 * symbol from there. This is how the application links to
3473 * dynamic linker services such as dlopen.
3475 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3476 res = symlook_obj(&req, &obj_rtld);
3479 defobj = req.defobj_out;
3483 assert(handle == RTLD_DEFAULT);
3484 res = symlook_default(&req, obj);
3486 defobj = req.defobj_out;
3491 if ((obj = dlcheck(handle)) == NULL) {
3492 lock_release(rtld_bind_lock, &lockstate);
3493 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3497 donelist_init(&donelist);
3498 if (obj->mainprog) {
3499 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3500 res = symlook_global(&req, &donelist);
3503 defobj = req.defobj_out;
3506 * Search the dynamic linker itself, and possibly resolve the
3507 * symbol from there. This is how the application links to
3508 * dynamic linker services such as dlopen.
3510 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3511 res = symlook_obj(&req, &obj_rtld);
3514 defobj = req.defobj_out;
3519 /* Search the whole DAG rooted at the given object. */
3520 res = symlook_list(&req, &obj->dagmembers, &donelist);
3523 defobj = req.defobj_out;
3529 lock_release(rtld_bind_lock, &lockstate);
3532 * The value required by the caller is derived from the value
3533 * of the symbol. this is simply the relocated value of the
3536 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3537 sym = make_function_pointer(def, defobj);
3538 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3539 sym = rtld_resolve_ifunc(defobj, def);
3540 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3541 ti.ti_module = defobj->tlsindex;
3542 ti.ti_offset = def->st_value;
3543 sym = __tls_get_addr(&ti);
3545 sym = defobj->relocbase + def->st_value;
3546 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3550 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3551 ve != NULL ? ve->name : "");
3552 lock_release(rtld_bind_lock, &lockstate);
3553 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3558 dlsym(void *handle, const char *name)
3560 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3565 dlfunc(void *handle, const char *name)
3572 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3578 dlvsym(void *handle, const char *name, const char *version)
3582 ventry.name = version;
3584 ventry.hash = elf_hash(version);
3586 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3591 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3593 const Obj_Entry *obj;
3594 RtldLockState lockstate;
3596 rlock_acquire(rtld_bind_lock, &lockstate);
3597 obj = obj_from_addr(addr);
3599 _rtld_error("No shared object contains address");
3600 lock_release(rtld_bind_lock, &lockstate);
3603 rtld_fill_dl_phdr_info(obj, phdr_info);
3604 lock_release(rtld_bind_lock, &lockstate);
3609 dladdr(const void *addr, Dl_info *info)
3611 const Obj_Entry *obj;
3614 unsigned long symoffset;
3615 RtldLockState lockstate;
3617 rlock_acquire(rtld_bind_lock, &lockstate);
3618 obj = obj_from_addr(addr);
3620 _rtld_error("No shared object contains address");
3621 lock_release(rtld_bind_lock, &lockstate);
3624 info->dli_fname = obj->path;
3625 info->dli_fbase = obj->mapbase;
3626 info->dli_saddr = (void *)0;
3627 info->dli_sname = NULL;
3630 * Walk the symbol list looking for the symbol whose address is
3631 * closest to the address sent in.
3633 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3634 def = obj->symtab + symoffset;
3637 * For skip the symbol if st_shndx is either SHN_UNDEF or
3640 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3644 * If the symbol is greater than the specified address, or if it
3645 * is further away from addr than the current nearest symbol,
3648 symbol_addr = obj->relocbase + def->st_value;
3649 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3652 /* Update our idea of the nearest symbol. */
3653 info->dli_sname = obj->strtab + def->st_name;
3654 info->dli_saddr = symbol_addr;
3657 if (info->dli_saddr == addr)
3660 lock_release(rtld_bind_lock, &lockstate);
3665 dlinfo(void *handle, int request, void *p)
3667 const Obj_Entry *obj;
3668 RtldLockState lockstate;
3671 rlock_acquire(rtld_bind_lock, &lockstate);
3673 if (handle == NULL || handle == RTLD_SELF) {
3676 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3677 if ((obj = obj_from_addr(retaddr)) == NULL)
3678 _rtld_error("Cannot determine caller's shared object");
3680 obj = dlcheck(handle);
3683 lock_release(rtld_bind_lock, &lockstate);
3689 case RTLD_DI_LINKMAP:
3690 *((struct link_map const **)p) = &obj->linkmap;
3692 case RTLD_DI_ORIGIN:
3693 error = rtld_dirname(obj->path, p);
3696 case RTLD_DI_SERINFOSIZE:
3697 case RTLD_DI_SERINFO:
3698 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3702 _rtld_error("Invalid request %d passed to dlinfo()", request);
3706 lock_release(rtld_bind_lock, &lockstate);
3712 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3715 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3716 phdr_info->dlpi_name = obj->path;
3717 phdr_info->dlpi_phdr = obj->phdr;
3718 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3719 phdr_info->dlpi_tls_modid = obj->tlsindex;
3720 phdr_info->dlpi_tls_data = obj->tlsinit;
3721 phdr_info->dlpi_adds = obj_loads;
3722 phdr_info->dlpi_subs = obj_loads - obj_count;
3726 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3728 struct dl_phdr_info phdr_info;
3729 Obj_Entry *obj, marker;
3730 RtldLockState bind_lockstate, phdr_lockstate;
3733 init_marker(&marker);
3736 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3737 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3738 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3739 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3740 rtld_fill_dl_phdr_info(obj, &phdr_info);
3742 lock_release(rtld_bind_lock, &bind_lockstate);
3744 error = callback(&phdr_info, sizeof phdr_info, param);
3746 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3748 obj = globallist_next(&marker);
3749 TAILQ_REMOVE(&obj_list, &marker, next);
3751 lock_release(rtld_bind_lock, &bind_lockstate);
3752 lock_release(rtld_phdr_lock, &phdr_lockstate);
3758 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3759 lock_release(rtld_bind_lock, &bind_lockstate);
3760 error = callback(&phdr_info, sizeof(phdr_info), param);
3762 lock_release(rtld_phdr_lock, &phdr_lockstate);
3767 fill_search_info(const char *dir, size_t dirlen, void *param)
3769 struct fill_search_info_args *arg;
3773 if (arg->request == RTLD_DI_SERINFOSIZE) {
3774 arg->serinfo->dls_cnt ++;
3775 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3777 struct dl_serpath *s_entry;
3779 s_entry = arg->serpath;
3780 s_entry->dls_name = arg->strspace;
3781 s_entry->dls_flags = arg->flags;
3783 strncpy(arg->strspace, dir, dirlen);
3784 arg->strspace[dirlen] = '\0';
3786 arg->strspace += dirlen + 1;
3794 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3796 struct dl_serinfo _info;
3797 struct fill_search_info_args args;
3799 args.request = RTLD_DI_SERINFOSIZE;
3800 args.serinfo = &_info;
3802 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3805 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3806 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3807 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3808 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3809 if (!obj->z_nodeflib)
3810 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3813 if (request == RTLD_DI_SERINFOSIZE) {
3814 info->dls_size = _info.dls_size;
3815 info->dls_cnt = _info.dls_cnt;
3819 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3820 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3824 args.request = RTLD_DI_SERINFO;
3825 args.serinfo = info;
3826 args.serpath = &info->dls_serpath[0];
3827 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3829 args.flags = LA_SER_RUNPATH;
3830 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
3833 args.flags = LA_SER_LIBPATH;
3834 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
3837 args.flags = LA_SER_RUNPATH;
3838 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
3841 args.flags = LA_SER_CONFIG;
3842 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
3846 args.flags = LA_SER_DEFAULT;
3847 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
3848 fill_search_info, NULL, &args) != NULL)
3854 rtld_dirname(const char *path, char *bname)
3858 /* Empty or NULL string gets treated as "." */
3859 if (path == NULL || *path == '\0') {
3865 /* Strip trailing slashes */
3866 endp = path + strlen(path) - 1;
3867 while (endp > path && *endp == '/')
3870 /* Find the start of the dir */
3871 while (endp > path && *endp != '/')
3874 /* Either the dir is "/" or there are no slashes */
3876 bname[0] = *endp == '/' ? '/' : '.';
3882 } while (endp > path && *endp == '/');
3885 if (endp - path + 2 > PATH_MAX)
3887 _rtld_error("Filename is too long: %s", path);
3891 strncpy(bname, path, endp - path + 1);
3892 bname[endp - path + 1] = '\0';
3897 rtld_dirname_abs(const char *path, char *base)
3901 if (realpath(path, base) == NULL)
3903 dbg("%s -> %s", path, base);
3904 last = strrchr(base, '/');
3913 linkmap_add(Obj_Entry *obj)
3915 struct link_map *l = &obj->linkmap;
3916 struct link_map *prev;
3918 obj->linkmap.l_name = obj->path;
3919 obj->linkmap.l_addr = obj->mapbase;
3920 obj->linkmap.l_ld = obj->dynamic;
3922 /* GDB needs load offset on MIPS to use the symbols */
3923 obj->linkmap.l_offs = obj->relocbase;
3926 if (r_debug.r_map == NULL) {
3932 * Scan to the end of the list, but not past the entry for the
3933 * dynamic linker, which we want to keep at the very end.
3935 for (prev = r_debug.r_map;
3936 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3937 prev = prev->l_next)
3940 /* Link in the new entry. */
3942 l->l_next = prev->l_next;
3943 if (l->l_next != NULL)
3944 l->l_next->l_prev = l;
3949 linkmap_delete(Obj_Entry *obj)
3951 struct link_map *l = &obj->linkmap;
3953 if (l->l_prev == NULL) {
3954 if ((r_debug.r_map = l->l_next) != NULL)
3955 l->l_next->l_prev = NULL;
3959 if ((l->l_prev->l_next = l->l_next) != NULL)
3960 l->l_next->l_prev = l->l_prev;
3964 * Function for the debugger to set a breakpoint on to gain control.
3966 * The two parameters allow the debugger to easily find and determine
3967 * what the runtime loader is doing and to whom it is doing it.
3969 * When the loadhook trap is hit (r_debug_state, set at program
3970 * initialization), the arguments can be found on the stack:
3972 * +8 struct link_map *m
3973 * +4 struct r_debug *rd
3977 r_debug_state(struct r_debug* rd, struct link_map *m)
3980 * The following is a hack to force the compiler to emit calls to
3981 * this function, even when optimizing. If the function is empty,
3982 * the compiler is not obliged to emit any code for calls to it,
3983 * even when marked __noinline. However, gdb depends on those
3986 __compiler_membar();
3990 * A function called after init routines have completed. This can be used to
3991 * break before a program's entry routine is called, and can be used when
3992 * main is not available in the symbol table.
3995 _r_debug_postinit(struct link_map *m)
3998 /* See r_debug_state(). */
3999 __compiler_membar();
4003 release_object(Obj_Entry *obj)
4006 if (obj->holdcount > 0) {
4007 obj->unholdfree = true;
4010 munmap(obj->mapbase, obj->mapsize);
4011 linkmap_delete(obj);
4016 * Get address of the pointer variable in the main program.
4017 * Prefer non-weak symbol over the weak one.
4019 static const void **
4020 get_program_var_addr(const char *name, RtldLockState *lockstate)
4025 symlook_init(&req, name);
4026 req.lockstate = lockstate;
4027 donelist_init(&donelist);
4028 if (symlook_global(&req, &donelist) != 0)
4030 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4031 return ((const void **)make_function_pointer(req.sym_out,
4033 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4034 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4036 return ((const void **)(req.defobj_out->relocbase +
4037 req.sym_out->st_value));
4041 * Set a pointer variable in the main program to the given value. This
4042 * is used to set key variables such as "environ" before any of the
4043 * init functions are called.
4046 set_program_var(const char *name, const void *value)
4050 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4051 dbg("\"%s\": *%p <-- %p", name, addr, value);
4057 * Search the global objects, including dependencies and main object,
4058 * for the given symbol.
4061 symlook_global(SymLook *req, DoneList *donelist)
4064 const Objlist_Entry *elm;
4067 symlook_init_from_req(&req1, req);
4069 /* Search all objects loaded at program start up. */
4070 if (req->defobj_out == NULL ||
4071 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4072 res = symlook_list(&req1, &list_main, donelist);
4073 if (res == 0 && (req->defobj_out == NULL ||
4074 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4075 req->sym_out = req1.sym_out;
4076 req->defobj_out = req1.defobj_out;
4077 assert(req->defobj_out != NULL);
4081 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4082 STAILQ_FOREACH(elm, &list_global, link) {
4083 if (req->defobj_out != NULL &&
4084 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4086 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4087 if (res == 0 && (req->defobj_out == NULL ||
4088 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4089 req->sym_out = req1.sym_out;
4090 req->defobj_out = req1.defobj_out;
4091 assert(req->defobj_out != NULL);
4095 return (req->sym_out != NULL ? 0 : ESRCH);
4099 * Given a symbol name in a referencing object, find the corresponding
4100 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4101 * no definition was found. Returns a pointer to the Obj_Entry of the
4102 * defining object via the reference parameter DEFOBJ_OUT.
4105 symlook_default(SymLook *req, const Obj_Entry *refobj)
4108 const Objlist_Entry *elm;
4112 donelist_init(&donelist);
4113 symlook_init_from_req(&req1, req);
4116 * Look first in the referencing object if linked symbolically,
4117 * and similarly handle protected symbols.
4119 res = symlook_obj(&req1, refobj);
4120 if (res == 0 && (refobj->symbolic ||
4121 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4122 req->sym_out = req1.sym_out;
4123 req->defobj_out = req1.defobj_out;
4124 assert(req->defobj_out != NULL);
4126 if (refobj->symbolic || req->defobj_out != NULL)
4127 donelist_check(&donelist, refobj);
4129 symlook_global(req, &donelist);
4131 /* Search all dlopened DAGs containing the referencing object. */
4132 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4133 if (req->sym_out != NULL &&
4134 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4136 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4137 if (res == 0 && (req->sym_out == NULL ||
4138 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4139 req->sym_out = req1.sym_out;
4140 req->defobj_out = req1.defobj_out;
4141 assert(req->defobj_out != NULL);
4146 * Search the dynamic linker itself, and possibly resolve the
4147 * symbol from there. This is how the application links to
4148 * dynamic linker services such as dlopen.
4150 if (req->sym_out == NULL ||
4151 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4152 res = symlook_obj(&req1, &obj_rtld);
4154 req->sym_out = req1.sym_out;
4155 req->defobj_out = req1.defobj_out;
4156 assert(req->defobj_out != NULL);
4160 return (req->sym_out != NULL ? 0 : ESRCH);
4164 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4167 const Obj_Entry *defobj;
4168 const Objlist_Entry *elm;
4174 STAILQ_FOREACH(elm, objlist, link) {
4175 if (donelist_check(dlp, elm->obj))
4177 symlook_init_from_req(&req1, req);
4178 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4179 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4181 defobj = req1.defobj_out;
4182 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4189 req->defobj_out = defobj;
4196 * Search the chain of DAGS cointed to by the given Needed_Entry
4197 * for a symbol of the given name. Each DAG is scanned completely
4198 * before advancing to the next one. Returns a pointer to the symbol,
4199 * or NULL if no definition was found.
4202 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4205 const Needed_Entry *n;
4206 const Obj_Entry *defobj;
4212 symlook_init_from_req(&req1, req);
4213 for (n = needed; n != NULL; n = n->next) {
4214 if (n->obj == NULL ||
4215 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4217 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4219 defobj = req1.defobj_out;
4220 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4226 req->defobj_out = defobj;
4233 * Search the symbol table of a single shared object for a symbol of
4234 * the given name and version, if requested. Returns a pointer to the
4235 * symbol, or NULL if no definition was found. If the object is
4236 * filter, return filtered symbol from filtee.
4238 * The symbol's hash value is passed in for efficiency reasons; that
4239 * eliminates many recomputations of the hash value.
4242 symlook_obj(SymLook *req, const Obj_Entry *obj)
4246 int flags, res, mres;
4249 * If there is at least one valid hash at this point, we prefer to
4250 * use the faster GNU version if available.
4252 if (obj->valid_hash_gnu)
4253 mres = symlook_obj1_gnu(req, obj);
4254 else if (obj->valid_hash_sysv)
4255 mres = symlook_obj1_sysv(req, obj);
4260 if (obj->needed_filtees != NULL) {
4261 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4262 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4263 donelist_init(&donelist);
4264 symlook_init_from_req(&req1, req);
4265 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4267 req->sym_out = req1.sym_out;
4268 req->defobj_out = req1.defobj_out;
4272 if (obj->needed_aux_filtees != NULL) {
4273 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4274 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4275 donelist_init(&donelist);
4276 symlook_init_from_req(&req1, req);
4277 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4279 req->sym_out = req1.sym_out;
4280 req->defobj_out = req1.defobj_out;
4288 /* Symbol match routine common to both hash functions */
4290 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4291 const unsigned long symnum)
4294 const Elf_Sym *symp;
4297 symp = obj->symtab + symnum;
4298 strp = obj->strtab + symp->st_name;
4300 switch (ELF_ST_TYPE(symp->st_info)) {
4306 if (symp->st_value == 0)
4310 if (symp->st_shndx != SHN_UNDEF)
4313 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4314 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4321 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4324 if (req->ventry == NULL) {
4325 if (obj->versyms != NULL) {
4326 verndx = VER_NDX(obj->versyms[symnum]);
4327 if (verndx > obj->vernum) {
4329 "%s: symbol %s references wrong version %d",
4330 obj->path, obj->strtab + symnum, verndx);
4334 * If we are not called from dlsym (i.e. this
4335 * is a normal relocation from unversioned
4336 * binary), accept the symbol immediately if
4337 * it happens to have first version after this
4338 * shared object became versioned. Otherwise,
4339 * if symbol is versioned and not hidden,
4340 * remember it. If it is the only symbol with
4341 * this name exported by the shared object, it
4342 * will be returned as a match by the calling
4343 * function. If symbol is global (verndx < 2)
4344 * accept it unconditionally.
4346 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4347 verndx == VER_NDX_GIVEN) {
4348 result->sym_out = symp;
4351 else if (verndx >= VER_NDX_GIVEN) {
4352 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4354 if (result->vsymp == NULL)
4355 result->vsymp = symp;
4361 result->sym_out = symp;
4364 if (obj->versyms == NULL) {
4365 if (object_match_name(obj, req->ventry->name)) {
4366 _rtld_error("%s: object %s should provide version %s "
4367 "for symbol %s", obj_rtld.path, obj->path,
4368 req->ventry->name, obj->strtab + symnum);
4372 verndx = VER_NDX(obj->versyms[symnum]);
4373 if (verndx > obj->vernum) {
4374 _rtld_error("%s: symbol %s references wrong version %d",
4375 obj->path, obj->strtab + symnum, verndx);
4378 if (obj->vertab[verndx].hash != req->ventry->hash ||
4379 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4381 * Version does not match. Look if this is a
4382 * global symbol and if it is not hidden. If
4383 * global symbol (verndx < 2) is available,
4384 * use it. Do not return symbol if we are
4385 * called by dlvsym, because dlvsym looks for
4386 * a specific version and default one is not
4387 * what dlvsym wants.
4389 if ((req->flags & SYMLOOK_DLSYM) ||
4390 (verndx >= VER_NDX_GIVEN) ||
4391 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4395 result->sym_out = symp;
4400 * Search for symbol using SysV hash function.
4401 * obj->buckets is known not to be NULL at this point; the test for this was
4402 * performed with the obj->valid_hash_sysv assignment.
4405 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4407 unsigned long symnum;
4408 Sym_Match_Result matchres;
4410 matchres.sym_out = NULL;
4411 matchres.vsymp = NULL;
4412 matchres.vcount = 0;
4414 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4415 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4416 if (symnum >= obj->nchains)
4417 return (ESRCH); /* Bad object */
4419 if (matched_symbol(req, obj, &matchres, symnum)) {
4420 req->sym_out = matchres.sym_out;
4421 req->defobj_out = obj;
4425 if (matchres.vcount == 1) {
4426 req->sym_out = matchres.vsymp;
4427 req->defobj_out = obj;
4433 /* Search for symbol using GNU hash function */
4435 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4437 Elf_Addr bloom_word;
4438 const Elf32_Word *hashval;
4440 Sym_Match_Result matchres;
4441 unsigned int h1, h2;
4442 unsigned long symnum;
4444 matchres.sym_out = NULL;
4445 matchres.vsymp = NULL;
4446 matchres.vcount = 0;
4448 /* Pick right bitmask word from Bloom filter array */
4449 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4450 obj->maskwords_bm_gnu];
4452 /* Calculate modulus word size of gnu hash and its derivative */
4453 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4454 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4456 /* Filter out the "definitely not in set" queries */
4457 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4460 /* Locate hash chain and corresponding value element*/
4461 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4464 hashval = &obj->chain_zero_gnu[bucket];
4466 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4467 symnum = hashval - obj->chain_zero_gnu;
4468 if (matched_symbol(req, obj, &matchres, symnum)) {
4469 req->sym_out = matchres.sym_out;
4470 req->defobj_out = obj;
4474 } while ((*hashval++ & 1) == 0);
4475 if (matchres.vcount == 1) {
4476 req->sym_out = matchres.vsymp;
4477 req->defobj_out = obj;
4484 trace_loaded_objects(Obj_Entry *obj)
4486 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4489 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4492 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4493 fmt1 = "\t%o => %p (%x)\n";
4495 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4496 fmt2 = "\t%o (%x)\n";
4498 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4500 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4501 Needed_Entry *needed;
4507 if (list_containers && obj->needed != NULL)
4508 rtld_printf("%s:\n", obj->path);
4509 for (needed = obj->needed; needed; needed = needed->next) {
4510 if (needed->obj != NULL) {
4511 if (needed->obj->traced && !list_containers)
4513 needed->obj->traced = true;
4514 path = needed->obj->path;
4518 name = (char *)obj->strtab + needed->name;
4519 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4521 fmt = is_lib ? fmt1 : fmt2;
4522 while ((c = *fmt++) != '\0') {
4548 rtld_putstr(main_local);
4551 rtld_putstr(obj_main->path);
4558 rtld_printf("%d", sodp->sod_major);
4561 rtld_printf("%d", sodp->sod_minor);
4568 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4581 * Unload a dlopened object and its dependencies from memory and from
4582 * our data structures. It is assumed that the DAG rooted in the
4583 * object has already been unreferenced, and that the object has a
4584 * reference count of 0.
4587 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4589 Obj_Entry marker, *obj, *next;
4591 assert(root->refcount == 0);
4594 * Pass over the DAG removing unreferenced objects from
4595 * appropriate lists.
4597 unlink_object(root);
4599 /* Unmap all objects that are no longer referenced. */
4600 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4601 next = TAILQ_NEXT(obj, next);
4602 if (obj->marker || obj->refcount != 0)
4604 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4605 obj->mapsize, 0, obj->path);
4606 dbg("unloading \"%s\"", obj->path);
4608 * Unlink the object now to prevent new references from
4609 * being acquired while the bind lock is dropped in
4610 * recursive dlclose() invocations.
4612 TAILQ_REMOVE(&obj_list, obj, next);
4615 if (obj->filtees_loaded) {
4617 init_marker(&marker);
4618 TAILQ_INSERT_BEFORE(next, &marker, next);
4619 unload_filtees(obj, lockstate);
4620 next = TAILQ_NEXT(&marker, next);
4621 TAILQ_REMOVE(&obj_list, &marker, next);
4623 unload_filtees(obj, lockstate);
4625 release_object(obj);
4630 unlink_object(Obj_Entry *root)
4634 if (root->refcount == 0) {
4635 /* Remove the object from the RTLD_GLOBAL list. */
4636 objlist_remove(&list_global, root);
4638 /* Remove the object from all objects' DAG lists. */
4639 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4640 objlist_remove(&elm->obj->dldags, root);
4641 if (elm->obj != root)
4642 unlink_object(elm->obj);
4648 ref_dag(Obj_Entry *root)
4652 assert(root->dag_inited);
4653 STAILQ_FOREACH(elm, &root->dagmembers, link)
4654 elm->obj->refcount++;
4658 unref_dag(Obj_Entry *root)
4662 assert(root->dag_inited);
4663 STAILQ_FOREACH(elm, &root->dagmembers, link)
4664 elm->obj->refcount--;
4668 * Common code for MD __tls_get_addr().
4670 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4672 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4674 Elf_Addr *newdtv, *dtv;
4675 RtldLockState lockstate;
4679 /* Check dtv generation in case new modules have arrived */
4680 if (dtv[0] != tls_dtv_generation) {
4681 wlock_acquire(rtld_bind_lock, &lockstate);
4682 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4684 if (to_copy > tls_max_index)
4685 to_copy = tls_max_index;
4686 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4687 newdtv[0] = tls_dtv_generation;
4688 newdtv[1] = tls_max_index;
4690 lock_release(rtld_bind_lock, &lockstate);
4691 dtv = *dtvp = newdtv;
4694 /* Dynamically allocate module TLS if necessary */
4695 if (dtv[index + 1] == 0) {
4696 /* Signal safe, wlock will block out signals. */
4697 wlock_acquire(rtld_bind_lock, &lockstate);
4698 if (!dtv[index + 1])
4699 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4700 lock_release(rtld_bind_lock, &lockstate);
4702 return ((void *)(dtv[index + 1] + offset));
4706 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4711 /* Check dtv generation in case new modules have arrived */
4712 if (__predict_true(dtv[0] == tls_dtv_generation &&
4713 dtv[index + 1] != 0))
4714 return ((void *)(dtv[index + 1] + offset));
4715 return (tls_get_addr_slow(dtvp, index, offset));
4718 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4719 defined(__powerpc__) || defined(__riscv__)
4722 * Allocate Static TLS using the Variant I method.
4725 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4734 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4737 assert(tcbsize >= TLS_TCB_SIZE);
4738 tcb = xcalloc(1, tls_static_space - TLS_TCB_SIZE + tcbsize);
4739 tls = (Elf_Addr **)(tcb + tcbsize - TLS_TCB_SIZE);
4741 if (oldtcb != NULL) {
4742 memcpy(tls, oldtcb, tls_static_space);
4745 /* Adjust the DTV. */
4747 for (i = 0; i < dtv[1]; i++) {
4748 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4749 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4750 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tls;
4754 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4756 dtv[0] = tls_dtv_generation;
4757 dtv[1] = tls_max_index;
4759 for (obj = globallist_curr(objs); obj != NULL;
4760 obj = globallist_next(obj)) {
4761 if (obj->tlsoffset > 0) {
4762 addr = (Elf_Addr)tls + obj->tlsoffset;
4763 if (obj->tlsinitsize > 0)
4764 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4765 if (obj->tlssize > obj->tlsinitsize)
4766 memset((void*) (addr + obj->tlsinitsize), 0,
4767 obj->tlssize - obj->tlsinitsize);
4768 dtv[obj->tlsindex + 1] = addr;
4777 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4780 Elf_Addr tlsstart, tlsend;
4783 assert(tcbsize >= TLS_TCB_SIZE);
4785 tlsstart = (Elf_Addr)tcb + tcbsize - TLS_TCB_SIZE;
4786 tlsend = tlsstart + tls_static_space;
4788 dtv = *(Elf_Addr **)tlsstart;
4790 for (i = 0; i < dtvsize; i++) {
4791 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4792 free((void*)dtv[i+2]);
4801 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4804 * Allocate Static TLS using the Variant II method.
4807 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4810 size_t size, ralign;
4812 Elf_Addr *dtv, *olddtv;
4813 Elf_Addr segbase, oldsegbase, addr;
4817 if (tls_static_max_align > ralign)
4818 ralign = tls_static_max_align;
4819 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4821 assert(tcbsize >= 2*sizeof(Elf_Addr));
4822 tls = malloc_aligned(size, ralign);
4823 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4825 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4826 ((Elf_Addr*)segbase)[0] = segbase;
4827 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4829 dtv[0] = tls_dtv_generation;
4830 dtv[1] = tls_max_index;
4834 * Copy the static TLS block over whole.
4836 oldsegbase = (Elf_Addr) oldtls;
4837 memcpy((void *)(segbase - tls_static_space),
4838 (const void *)(oldsegbase - tls_static_space),
4842 * If any dynamic TLS blocks have been created tls_get_addr(),
4845 olddtv = ((Elf_Addr**)oldsegbase)[1];
4846 for (i = 0; i < olddtv[1]; i++) {
4847 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4848 dtv[i+2] = olddtv[i+2];
4854 * We assume that this block was the one we created with
4855 * allocate_initial_tls().
4857 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4859 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4860 if (obj->marker || obj->tlsoffset == 0)
4862 addr = segbase - obj->tlsoffset;
4863 memset((void*) (addr + obj->tlsinitsize),
4864 0, obj->tlssize - obj->tlsinitsize);
4866 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4867 obj->static_tls_copied = true;
4869 dtv[obj->tlsindex + 1] = addr;
4873 return (void*) segbase;
4877 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4880 size_t size, ralign;
4882 Elf_Addr tlsstart, tlsend;
4885 * Figure out the size of the initial TLS block so that we can
4886 * find stuff which ___tls_get_addr() allocated dynamically.
4889 if (tls_static_max_align > ralign)
4890 ralign = tls_static_max_align;
4891 size = round(tls_static_space, ralign);
4893 dtv = ((Elf_Addr**)tls)[1];
4895 tlsend = (Elf_Addr) tls;
4896 tlsstart = tlsend - size;
4897 for (i = 0; i < dtvsize; i++) {
4898 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4899 free_aligned((void *)dtv[i + 2]);
4903 free_aligned((void *)tlsstart);
4910 * Allocate TLS block for module with given index.
4913 allocate_module_tls(int index)
4918 TAILQ_FOREACH(obj, &obj_list, next) {
4921 if (obj->tlsindex == index)
4925 _rtld_error("Can't find module with TLS index %d", index);
4929 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4930 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4931 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4937 allocate_tls_offset(Obj_Entry *obj)
4944 if (obj->tlssize == 0) {
4945 obj->tls_done = true;
4949 if (tls_last_offset == 0)
4950 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4952 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4953 obj->tlssize, obj->tlsalign);
4956 * If we have already fixed the size of the static TLS block, we
4957 * must stay within that size. When allocating the static TLS, we
4958 * leave a small amount of space spare to be used for dynamically
4959 * loading modules which use static TLS.
4961 if (tls_static_space != 0) {
4962 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4964 } else if (obj->tlsalign > tls_static_max_align) {
4965 tls_static_max_align = obj->tlsalign;
4968 tls_last_offset = obj->tlsoffset = off;
4969 tls_last_size = obj->tlssize;
4970 obj->tls_done = true;
4976 free_tls_offset(Obj_Entry *obj)
4980 * If we were the last thing to allocate out of the static TLS
4981 * block, we give our space back to the 'allocator'. This is a
4982 * simplistic workaround to allow libGL.so.1 to be loaded and
4983 * unloaded multiple times.
4985 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4986 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4987 tls_last_offset -= obj->tlssize;
4993 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
4996 RtldLockState lockstate;
4998 wlock_acquire(rtld_bind_lock, &lockstate);
4999 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5001 lock_release(rtld_bind_lock, &lockstate);
5006 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5008 RtldLockState lockstate;
5010 wlock_acquire(rtld_bind_lock, &lockstate);
5011 free_tls(tcb, tcbsize, tcbalign);
5012 lock_release(rtld_bind_lock, &lockstate);
5016 object_add_name(Obj_Entry *obj, const char *name)
5022 entry = malloc(sizeof(Name_Entry) + len);
5024 if (entry != NULL) {
5025 strcpy(entry->name, name);
5026 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5031 object_match_name(const Obj_Entry *obj, const char *name)
5035 STAILQ_FOREACH(entry, &obj->names, link) {
5036 if (strcmp(name, entry->name) == 0)
5043 locate_dependency(const Obj_Entry *obj, const char *name)
5045 const Objlist_Entry *entry;
5046 const Needed_Entry *needed;
5048 STAILQ_FOREACH(entry, &list_main, link) {
5049 if (object_match_name(entry->obj, name))
5053 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5054 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5055 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5057 * If there is DT_NEEDED for the name we are looking for,
5058 * we are all set. Note that object might not be found if
5059 * dependency was not loaded yet, so the function can
5060 * return NULL here. This is expected and handled
5061 * properly by the caller.
5063 return (needed->obj);
5066 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5072 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5073 const Elf_Vernaux *vna)
5075 const Elf_Verdef *vd;
5076 const char *vername;
5078 vername = refobj->strtab + vna->vna_name;
5079 vd = depobj->verdef;
5081 _rtld_error("%s: version %s required by %s not defined",
5082 depobj->path, vername, refobj->path);
5086 if (vd->vd_version != VER_DEF_CURRENT) {
5087 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5088 depobj->path, vd->vd_version);
5091 if (vna->vna_hash == vd->vd_hash) {
5092 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5093 ((char *)vd + vd->vd_aux);
5094 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5097 if (vd->vd_next == 0)
5099 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5101 if (vna->vna_flags & VER_FLG_WEAK)
5103 _rtld_error("%s: version %s required by %s not found",
5104 depobj->path, vername, refobj->path);
5109 rtld_verify_object_versions(Obj_Entry *obj)
5111 const Elf_Verneed *vn;
5112 const Elf_Verdef *vd;
5113 const Elf_Verdaux *vda;
5114 const Elf_Vernaux *vna;
5115 const Obj_Entry *depobj;
5116 int maxvernum, vernum;
5118 if (obj->ver_checked)
5120 obj->ver_checked = true;
5124 * Walk over defined and required version records and figure out
5125 * max index used by any of them. Do very basic sanity checking
5129 while (vn != NULL) {
5130 if (vn->vn_version != VER_NEED_CURRENT) {
5131 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5132 obj->path, vn->vn_version);
5135 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
5137 vernum = VER_NEED_IDX(vna->vna_other);
5138 if (vernum > maxvernum)
5140 if (vna->vna_next == 0)
5142 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
5144 if (vn->vn_next == 0)
5146 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
5150 while (vd != NULL) {
5151 if (vd->vd_version != VER_DEF_CURRENT) {
5152 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5153 obj->path, vd->vd_version);
5156 vernum = VER_DEF_IDX(vd->vd_ndx);
5157 if (vernum > maxvernum)
5159 if (vd->vd_next == 0)
5161 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5168 * Store version information in array indexable by version index.
5169 * Verify that object version requirements are satisfied along the
5172 obj->vernum = maxvernum + 1;
5173 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5176 while (vd != NULL) {
5177 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5178 vernum = VER_DEF_IDX(vd->vd_ndx);
5179 assert(vernum <= maxvernum);
5180 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
5181 obj->vertab[vernum].hash = vd->vd_hash;
5182 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5183 obj->vertab[vernum].file = NULL;
5184 obj->vertab[vernum].flags = 0;
5186 if (vd->vd_next == 0)
5188 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5192 while (vn != NULL) {
5193 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5196 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
5198 if (check_object_provided_version(obj, depobj, vna))
5200 vernum = VER_NEED_IDX(vna->vna_other);
5201 assert(vernum <= maxvernum);
5202 obj->vertab[vernum].hash = vna->vna_hash;
5203 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5204 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5205 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5206 VER_INFO_HIDDEN : 0;
5207 if (vna->vna_next == 0)
5209 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
5211 if (vn->vn_next == 0)
5213 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
5219 rtld_verify_versions(const Objlist *objlist)
5221 Objlist_Entry *entry;
5225 STAILQ_FOREACH(entry, objlist, link) {
5227 * Skip dummy objects or objects that have their version requirements
5230 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5232 if (rtld_verify_object_versions(entry->obj) == -1) {
5234 if (ld_tracing == NULL)
5238 if (rc == 0 || ld_tracing != NULL)
5239 rc = rtld_verify_object_versions(&obj_rtld);
5244 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5249 vernum = VER_NDX(obj->versyms[symnum]);
5250 if (vernum >= obj->vernum) {
5251 _rtld_error("%s: symbol %s has wrong verneed value %d",
5252 obj->path, obj->strtab + symnum, vernum);
5253 } else if (obj->vertab[vernum].hash != 0) {
5254 return &obj->vertab[vernum];
5261 _rtld_get_stack_prot(void)
5264 return (stack_prot);
5268 _rtld_is_dlopened(void *arg)
5271 RtldLockState lockstate;
5274 rlock_acquire(rtld_bind_lock, &lockstate);
5277 obj = obj_from_addr(arg);
5279 _rtld_error("No shared object contains address");
5280 lock_release(rtld_bind_lock, &lockstate);
5283 res = obj->dlopened ? 1 : 0;
5284 lock_release(rtld_bind_lock, &lockstate);
5289 obj_remap_relro(Obj_Entry *obj, int prot)
5292 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5294 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5295 obj->path, prot, rtld_strerror(errno));
5302 obj_disable_relro(Obj_Entry *obj)
5305 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5309 obj_enforce_relro(Obj_Entry *obj)
5312 return (obj_remap_relro(obj, PROT_READ));
5316 map_stacks_exec(RtldLockState *lockstate)
5318 void (*thr_map_stacks_exec)(void);
5320 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5322 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5323 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5324 if (thr_map_stacks_exec != NULL) {
5325 stack_prot |= PROT_EXEC;
5326 thr_map_stacks_exec();
5331 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5335 void (*distrib)(size_t, void *, size_t, size_t);
5337 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5338 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5339 if (distrib == NULL)
5341 STAILQ_FOREACH(elm, list, link) {
5343 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5345 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5347 obj->static_tls_copied = true;
5352 symlook_init(SymLook *dst, const char *name)
5355 bzero(dst, sizeof(*dst));
5357 dst->hash = elf_hash(name);
5358 dst->hash_gnu = gnu_hash(name);
5362 symlook_init_from_req(SymLook *dst, const SymLook *src)
5365 dst->name = src->name;
5366 dst->hash = src->hash;
5367 dst->hash_gnu = src->hash_gnu;
5368 dst->ventry = src->ventry;
5369 dst->flags = src->flags;
5370 dst->defobj_out = NULL;
5371 dst->sym_out = NULL;
5372 dst->lockstate = src->lockstate;
5376 open_binary_fd(const char *argv0, bool search_in_path)
5378 char *pathenv, *pe, binpath[PATH_MAX];
5381 if (search_in_path && strchr(argv0, '/') == NULL) {
5382 pathenv = getenv("PATH");
5383 if (pathenv == NULL) {
5384 rtld_printf("-p and no PATH environment variable\n");
5387 pathenv = strdup(pathenv);
5388 if (pathenv == NULL) {
5389 rtld_printf("Cannot allocate memory\n");
5394 while ((pe = strsep(&pathenv, ":")) != NULL) {
5395 if (strlcpy(binpath, pe, sizeof(binpath)) >=
5398 if (binpath[0] != '\0' &&
5399 strlcat(binpath, "/", sizeof(binpath)) >=
5402 if (strlcat(binpath, argv0, sizeof(binpath)) >=
5405 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5406 if (fd != -1 || errno != ENOENT)
5411 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5415 rtld_printf("Opening %s: %s\n", argv0,
5416 rtld_strerror(errno));
5423 * Parse a set of command-line arguments.
5426 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp)
5429 int fd, i, j, arglen;
5432 dbg("Parsing command-line arguments");
5436 for (i = 1; i < argc; i++ ) {
5438 dbg("argv[%d]: '%s'", i, arg);
5441 * rtld arguments end with an explicit "--" or with the first
5442 * non-prefixed argument.
5444 if (strcmp(arg, "--") == 0) {
5452 * All other arguments are single-character options that can
5453 * be combined, so we need to search through `arg` for them.
5455 arglen = strlen(arg);
5456 for (j = 1; j < arglen; j++) {
5459 print_usage(argv[0]);
5461 } else if (opt == 'f') {
5463 * -f XX can be used to specify a descriptor for the
5464 * binary named at the command line (i.e., the later
5465 * argument will specify the process name but the
5466 * descriptor is what will actually be executed)
5468 if (j != arglen - 1) {
5469 /* -f must be the last option in, e.g., -abcf */
5470 _rtld_error("invalid options: %s", arg);
5474 fd = parse_integer(argv[i]);
5476 _rtld_error("invalid file descriptor: '%s'",
5482 } else if (opt == 'p') {
5485 rtld_printf("invalid argument: '%s'\n", arg);
5486 print_usage(argv[0]);
5496 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5499 parse_integer(const char *str)
5501 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5508 for (c = *str; c != '\0'; c = *++str) {
5509 if (c < '0' || c > '9')
5516 /* Make sure we actually parsed something. */
5523 print_usage(const char *argv0)
5526 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n"
5529 " -h Display this help message\n"
5530 " -p Search in PATH for named binary\n"
5531 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5532 " -- End of RTLD options\n"
5533 " <binary> Name of process to execute\n"
5534 " <args> Arguments to the executed process\n", argv0);
5538 * Overrides for libc_pic-provided functions.
5542 __getosreldate(void)
5552 oid[1] = KERN_OSRELDATE;
5554 len = sizeof(osrel);
5555 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5556 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5568 void (*__cleanup)(void);
5569 int __isthreaded = 0;
5570 int _thread_autoinit_dummy_decl = 1;
5573 * No unresolved symbols for rtld.
5576 __pthread_cxa_finalize(struct dl_phdr_info *a)
5581 __stack_chk_fail(void)
5584 _rtld_error("stack overflow detected; terminated");
5587 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);
5593 _rtld_error("buffer overflow detected; terminated");
5598 rtld_strerror(int errnum)
5601 if (errnum < 0 || errnum >= sys_nerr)
5602 return ("Unknown error");
5603 return (sys_errlist[errnum]);
5607 * No ifunc relocations.
5610 memset(void *dest, int c, size_t len)
5614 for (i = 0; i < len; i++)
5615 ((char *)dest)[i] = c;
5620 bzero(void *dest, size_t len)
5624 for (i = 0; i < len; i++)
5625 ((char *)dest)[i] = 0;