2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Copyright 2012 John Marino <draco@marino.st>.
8 * Copyright 2014-2017 The FreeBSD Foundation
11 * Portions of this software were developed by Konstantin Belousov
12 * under sponsorship from the FreeBSD Foundation.
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 * Dynamic linker for ELF.
38 * John Polstra <jdp@polstra.com>.
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
44 #include <sys/param.h>
45 #include <sys/mount.h>
48 #include <sys/sysctl.h>
50 #include <sys/utsname.h>
51 #include <sys/ktrace.h>
68 #include "rtld_printf.h"
69 #include "rtld_utrace.h"
73 typedef void (*func_ptr_type)();
74 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
77 * Function declarations.
79 static const char *basename(const char *);
80 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
81 const Elf_Dyn **, const Elf_Dyn **);
82 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
84 static void digest_dynamic(Obj_Entry *, int);
85 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
86 static Obj_Entry *dlcheck(void *);
87 static int dlclose_locked(void *, RtldLockState *);
88 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
89 int lo_flags, int mode, RtldLockState *lockstate);
90 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
91 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
92 static bool donelist_check(DoneList *, const Obj_Entry *);
93 static void errmsg_restore(char *);
94 static char *errmsg_save(void);
95 static void *fill_search_info(const char *, size_t, void *);
96 static char *find_library(const char *, const Obj_Entry *, int *);
97 static const char *gethints(bool);
98 static void hold_object(Obj_Entry *);
99 static void unhold_object(Obj_Entry *);
100 static void init_dag(Obj_Entry *);
101 static void init_marker(Obj_Entry *);
102 static void init_pagesizes(Elf_Auxinfo **aux_info);
103 static void init_rtld(caddr_t, Elf_Auxinfo **);
104 static void initlist_add_neededs(Needed_Entry *, Objlist *);
105 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
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_enforce_relro(Obj_Entry *);
115 static Obj_Entry *obj_from_addr(const void *);
116 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
117 static void objlist_call_init(Objlist *, RtldLockState *);
118 static void objlist_clear(Objlist *);
119 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
120 static void objlist_init(Objlist *);
121 static void objlist_push_head(Objlist *, Obj_Entry *);
122 static void objlist_push_tail(Objlist *, Obj_Entry *);
123 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
124 static void objlist_remove(Objlist *, Obj_Entry *);
125 static int open_binary_fd(const char *argv0, bool search_in_path);
126 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp);
127 static int parse_integer(const char *);
128 static void *path_enumerate(const char *, path_enum_proc, void *);
129 static void print_usage(const char *argv0);
130 static void release_object(Obj_Entry *);
131 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
132 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
133 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
134 int flags, RtldLockState *lockstate);
135 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
137 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
138 int flags, RtldLockState *lockstate);
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 *, int *);
144 static char *search_library_pathfds(const char *, const char *, int *);
145 static const void **get_program_var_addr(const char *, RtldLockState *);
146 static void set_program_var(const char *, const void *);
147 static int symlook_default(SymLook *, const Obj_Entry *refobj);
148 static int symlook_global(SymLook *, DoneList *);
149 static void symlook_init_from_req(SymLook *, const SymLook *);
150 static int symlook_list(SymLook *, const Objlist *, DoneList *);
151 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
152 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
153 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
154 static void trace_loaded_objects(Obj_Entry *);
155 static void unlink_object(Obj_Entry *);
156 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
157 static void unref_dag(Obj_Entry *);
158 static void ref_dag(Obj_Entry *);
159 static char *origin_subst_one(Obj_Entry *, char *, const char *,
161 static char *origin_subst(Obj_Entry *, char *);
162 static bool obj_resolve_origin(Obj_Entry *obj);
163 static void preinit_main(void);
164 static int rtld_verify_versions(const Objlist *);
165 static int rtld_verify_object_versions(Obj_Entry *);
166 static void object_add_name(Obj_Entry *, const char *);
167 static int object_match_name(const Obj_Entry *, const char *);
168 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
169 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
170 struct dl_phdr_info *phdr_info);
171 static uint32_t gnu_hash(const char *);
172 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
173 const unsigned long);
175 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
176 void _r_debug_postinit(struct link_map *) __noinline __exported;
178 int __sys_openat(int, const char *, int, ...);
183 static char *error_message; /* Message for dlerror(), or NULL */
184 struct r_debug r_debug __exported; /* for GDB; */
185 static bool libmap_disable; /* Disable libmap */
186 static bool ld_loadfltr; /* Immediate filters processing */
187 static char *libmap_override; /* Maps to use in addition to libmap.conf */
188 static bool trust; /* False for setuid and setgid programs */
189 static bool dangerous_ld_env; /* True if environment variables have been
190 used to affect the libraries loaded */
191 bool ld_bind_not; /* Disable PLT update */
192 static char *ld_bind_now; /* Environment variable for immediate binding */
193 static char *ld_debug; /* Environment variable for debugging */
194 static char *ld_library_path; /* Environment variable for search path */
195 static char *ld_library_dirs; /* Environment variable for library descriptors */
196 static char *ld_preload; /* Environment variable for libraries to
198 static char *ld_elf_hints_path; /* Environment variable for alternative hints path */
199 static char *ld_tracing; /* Called from ldd to print libs */
200 static char *ld_utrace; /* Use utrace() to log events. */
201 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
202 static Obj_Entry *obj_main; /* The main program shared object */
203 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
204 static unsigned int obj_count; /* Number of objects in obj_list */
205 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
207 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
208 STAILQ_HEAD_INITIALIZER(list_global);
209 static Objlist list_main = /* Objects loaded at program startup */
210 STAILQ_HEAD_INITIALIZER(list_main);
211 static Objlist list_fini = /* Objects needing fini() calls */
212 STAILQ_HEAD_INITIALIZER(list_fini);
214 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
216 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
218 extern Elf_Dyn _DYNAMIC;
219 #pragma weak _DYNAMIC
221 int dlclose(void *) __exported;
222 char *dlerror(void) __exported;
223 void *dlopen(const char *, int) __exported;
224 void *fdlopen(int, int) __exported;
225 void *dlsym(void *, const char *) __exported;
226 dlfunc_t dlfunc(void *, const char *) __exported;
227 void *dlvsym(void *, const char *, const char *) __exported;
228 int dladdr(const void *, Dl_info *) __exported;
229 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
230 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
231 int dlinfo(void *, int , void *) __exported;
232 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
233 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
234 int _rtld_get_stack_prot(void) __exported;
235 int _rtld_is_dlopened(void *) __exported;
236 void _rtld_error(const char *, ...) __exported;
238 int npagesizes, osreldate;
241 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
242 static int max_stack_flags;
245 * Global declarations normally provided by crt1. The dynamic linker is
246 * not built with crt1, so we have to provide them ourselves.
252 * Used to pass argc, argv to init functions.
258 * Globals to control TLS allocation.
260 size_t tls_last_offset; /* Static TLS offset of last module */
261 size_t tls_last_size; /* Static TLS size of last module */
262 size_t tls_static_space; /* Static TLS space allocated */
263 size_t tls_static_max_align;
264 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
265 int tls_max_index = 1; /* Largest module index allocated */
267 bool ld_library_path_rpath = false;
270 * Globals for path names, and such
272 char *ld_elf_hints_default = _PATH_ELF_HINTS;
273 char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
274 char *ld_path_rtld = _PATH_RTLD;
275 char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
276 char *ld_env_prefix = LD_;
279 * Fill in a DoneList with an allocation large enough to hold all of
280 * the currently-loaded objects. Keep this as a macro since it calls
281 * alloca and we want that to occur within the scope of the caller.
283 #define donelist_init(dlp) \
284 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
285 assert((dlp)->objs != NULL), \
286 (dlp)->num_alloc = obj_count, \
289 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
290 if (ld_utrace != NULL) \
291 ld_utrace_log(e, h, mb, ms, r, n); \
295 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
296 int refcnt, const char *name)
298 struct utrace_rtld ut;
299 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
301 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
304 ut.mapbase = mapbase;
305 ut.mapsize = mapsize;
307 bzero(ut.name, sizeof(ut.name));
309 strlcpy(ut.name, name, sizeof(ut.name));
310 utrace(&ut, sizeof(ut));
313 #ifdef RTLD_VARIANT_ENV_NAMES
315 * construct the env variable based on the type of binary that's
318 static inline const char *
321 static char buffer[128];
323 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
324 strlcat(buffer, var, sizeof(buffer));
332 * Main entry point for dynamic linking. The first argument is the
333 * stack pointer. The stack is expected to be laid out as described
334 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
335 * Specifically, the stack pointer points to a word containing
336 * ARGC. Following that in the stack is a null-terminated sequence
337 * of pointers to argument strings. Then comes a null-terminated
338 * sequence of pointers to environment strings. Finally, there is a
339 * sequence of "auxiliary vector" entries.
341 * The second argument points to a place to store the dynamic linker's
342 * exit procedure pointer and the third to a place to store the main
345 * The return value is the main program's entry point.
348 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
350 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
351 Objlist_Entry *entry;
352 Obj_Entry *last_interposer, *obj, *preload_tail;
353 const Elf_Phdr *phdr;
355 RtldLockState lockstate;
358 char **argv, *argv0, **env, **envp, *kexecpath, *library_path_rpath;
360 char buf[MAXPATHLEN];
361 int argc, fd, i, phnum, rtld_argc;
362 bool dir_enable, explicit_fd, search_in_path;
365 * On entry, the dynamic linker itself has not been relocated yet.
366 * Be very careful not to reference any global data until after
367 * init_rtld has returned. It is OK to reference file-scope statics
368 * and string constants, and to call static and global functions.
371 /* Find the auxiliary vector on the stack. */
375 sp += argc + 1; /* Skip over arguments and NULL terminator */
377 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
379 aux = (Elf_Auxinfo *) sp;
381 /* Digest the auxiliary vector. */
382 for (i = 0; i < AT_COUNT; i++)
384 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
385 if (auxp->a_type < AT_COUNT)
386 aux_info[auxp->a_type] = auxp;
389 /* Initialize and relocate ourselves. */
390 assert(aux_info[AT_BASE] != NULL);
391 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
393 __progname = obj_rtld.path;
394 argv0 = argv[0] != NULL ? argv[0] : "(null)";
399 trust = !issetugid();
401 md_abi_variant_hook(aux_info);
404 if (aux_info[AT_EXECFD] != NULL) {
405 fd = aux_info[AT_EXECFD]->a_un.a_val;
407 assert(aux_info[AT_PHDR] != NULL);
408 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
409 if (phdr == obj_rtld.phdr) {
411 _rtld_error("Tainted process refusing to run binary %s",
415 dbg("opening main program in direct exec mode");
417 rtld_argc = parse_args(argv, argc, &search_in_path, &fd);
418 argv0 = argv[rtld_argc];
419 explicit_fd = (fd != -1);
421 fd = open_binary_fd(argv0, search_in_path);
422 if (fstat(fd, &st) == -1) {
423 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
424 explicit_fd ? "user-provided descriptor" : argv0,
425 rtld_strerror(errno));
430 * Rough emulation of the permission checks done by
431 * execve(2), only Unix DACs are checked, ACLs are
432 * ignored. Preserve the semantic of disabling owner
433 * to execute if owner x bit is cleared, even if
434 * others x bit is enabled.
435 * mmap(2) does not allow to mmap with PROT_EXEC if
436 * binary' file comes from noexec mount. We cannot
437 * set VV_TEXT on the binary.
440 if (st.st_uid == geteuid()) {
441 if ((st.st_mode & S_IXUSR) != 0)
443 } else if (st.st_gid == getegid()) {
444 if ((st.st_mode & S_IXGRP) != 0)
446 } else if ((st.st_mode & S_IXOTH) != 0) {
450 _rtld_error("No execute permission for binary %s",
456 * For direct exec mode, argv[0] is the interpreter
457 * name, we must remove it and shift arguments left
458 * before invoking binary main. Since stack layout
459 * places environment pointers and aux vectors right
460 * after the terminating NULL, we must shift
461 * environment and aux as well.
463 main_argc = argc - rtld_argc;
464 for (i = 0; i <= main_argc; i++)
465 argv[i] = argv[i + rtld_argc];
467 environ = env = envp = argv + main_argc + 1;
469 *envp = *(envp + rtld_argc);
471 } while (*envp != NULL);
472 aux = auxp = (Elf_Auxinfo *)envp;
473 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
474 for (;; auxp++, auxpf++) {
476 if (auxp->a_type == AT_NULL)
480 _rtld_error("No binary");
486 ld_bind_now = getenv(_LD("BIND_NOW"));
489 * If the process is tainted, then we un-set the dangerous environment
490 * variables. The process will be marked as tainted until setuid(2)
491 * is called. If any child process calls setuid(2) we do not want any
492 * future processes to honor the potentially un-safe variables.
495 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
496 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
497 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
498 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
499 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
500 _rtld_error("environment corrupt; aborting");
504 ld_debug = getenv(_LD("DEBUG"));
505 if (ld_bind_now == NULL)
506 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
507 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
508 libmap_override = getenv(_LD("LIBMAP"));
509 ld_library_path = getenv(_LD("LIBRARY_PATH"));
510 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
511 ld_preload = getenv(_LD("PRELOAD"));
512 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
513 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
514 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
515 if (library_path_rpath != NULL) {
516 if (library_path_rpath[0] == 'y' ||
517 library_path_rpath[0] == 'Y' ||
518 library_path_rpath[0] == '1')
519 ld_library_path_rpath = true;
521 ld_library_path_rpath = false;
523 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
524 (ld_library_path != NULL) || (ld_preload != NULL) ||
525 (ld_elf_hints_path != NULL) || ld_loadfltr;
526 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
527 ld_utrace = getenv(_LD("UTRACE"));
529 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
530 ld_elf_hints_path = ld_elf_hints_default;
532 if (ld_debug != NULL && *ld_debug != '\0')
534 dbg("%s is initialized, base address = %p", __progname,
535 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
536 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
537 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
539 dbg("initializing thread locks");
543 * Load the main program, or process its program header if it is
546 if (fd != -1) { /* Load the main program. */
547 dbg("loading main program");
548 obj_main = map_object(fd, argv0, NULL);
550 if (obj_main == NULL)
552 max_stack_flags = obj_main->stack_flags;
553 } else { /* Main program already loaded. */
554 dbg("processing main program's program header");
555 assert(aux_info[AT_PHDR] != NULL);
556 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
557 assert(aux_info[AT_PHNUM] != NULL);
558 phnum = aux_info[AT_PHNUM]->a_un.a_val;
559 assert(aux_info[AT_PHENT] != NULL);
560 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
561 assert(aux_info[AT_ENTRY] != NULL);
562 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
563 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
567 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
568 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
569 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
570 if (kexecpath[0] == '/')
571 obj_main->path = kexecpath;
572 else if (getcwd(buf, sizeof(buf)) == NULL ||
573 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
574 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
575 obj_main->path = xstrdup(argv0);
577 obj_main->path = xstrdup(buf);
579 dbg("No AT_EXECPATH or direct exec");
580 obj_main->path = xstrdup(argv0);
582 dbg("obj_main path %s", obj_main->path);
583 obj_main->mainprog = true;
585 if (aux_info[AT_STACKPROT] != NULL &&
586 aux_info[AT_STACKPROT]->a_un.a_val != 0)
587 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
591 * Get the actual dynamic linker pathname from the executable if
592 * possible. (It should always be possible.) That ensures that
593 * gdb will find the right dynamic linker even if a non-standard
596 if (obj_main->interp != NULL &&
597 strcmp(obj_main->interp, obj_rtld.path) != 0) {
599 obj_rtld.path = xstrdup(obj_main->interp);
600 __progname = obj_rtld.path;
604 digest_dynamic(obj_main, 0);
605 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
606 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
607 obj_main->dynsymcount);
609 linkmap_add(obj_main);
610 linkmap_add(&obj_rtld);
612 /* Link the main program into the list of objects. */
613 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
617 /* Initialize a fake symbol for resolving undefined weak references. */
618 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
619 sym_zero.st_shndx = SHN_UNDEF;
620 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
623 libmap_disable = (bool)lm_init(libmap_override);
625 dbg("loading LD_PRELOAD libraries");
626 if (load_preload_objects() == -1)
628 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
630 dbg("loading needed objects");
631 if (load_needed_objects(obj_main, 0) == -1)
634 /* Make a list of all objects loaded at startup. */
635 last_interposer = obj_main;
636 TAILQ_FOREACH(obj, &obj_list, next) {
639 if (obj->z_interpose && obj != obj_main) {
640 objlist_put_after(&list_main, last_interposer, obj);
641 last_interposer = obj;
643 objlist_push_tail(&list_main, obj);
648 dbg("checking for required versions");
649 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
652 if (ld_tracing) { /* We're done */
653 trace_loaded_objects(obj_main);
657 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
658 dump_relocations(obj_main);
663 * Processing tls relocations requires having the tls offsets
664 * initialized. Prepare offsets before starting initial
665 * relocation processing.
667 dbg("initializing initial thread local storage offsets");
668 STAILQ_FOREACH(entry, &list_main, link) {
670 * Allocate all the initial objects out of the static TLS
671 * block even if they didn't ask for it.
673 allocate_tls_offset(entry->obj);
676 if (relocate_objects(obj_main,
677 ld_bind_now != NULL && *ld_bind_now != '\0',
678 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
681 dbg("doing copy relocations");
682 if (do_copy_relocations(obj_main) == -1)
685 dbg("enforcing main obj relro");
686 if (obj_enforce_relro(obj_main) == -1)
689 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
690 dump_relocations(obj_main);
695 * Setup TLS for main thread. This must be done after the
696 * relocations are processed, since tls initialization section
697 * might be the subject for relocations.
699 dbg("initializing initial thread local storage");
700 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
702 dbg("initializing key program variables");
703 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
704 set_program_var("environ", env);
705 set_program_var("__elf_aux_vector", aux);
707 /* Make a list of init functions to call. */
708 objlist_init(&initlist);
709 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
710 preload_tail, &initlist);
712 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
714 map_stacks_exec(NULL);
717 dbg("resolving ifuncs");
718 if (resolve_objects_ifunc(obj_main,
719 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
723 if (!obj_main->crt_no_init) {
725 * Make sure we don't call the main program's init and fini
726 * functions for binaries linked with old crt1 which calls
729 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
730 obj_main->preinit_array = obj_main->init_array =
731 obj_main->fini_array = (Elf_Addr)NULL;
735 * Execute MD initializers required before we call the objects'
740 wlock_acquire(rtld_bind_lock, &lockstate);
741 if (obj_main->crt_no_init)
743 objlist_call_init(&initlist, &lockstate);
744 _r_debug_postinit(&obj_main->linkmap);
745 objlist_clear(&initlist);
746 dbg("loading filtees");
747 TAILQ_FOREACH(obj, &obj_list, next) {
750 if (ld_loadfltr || obj->z_loadfltr)
751 load_filtees(obj, 0, &lockstate);
753 lock_release(rtld_bind_lock, &lockstate);
755 dbg("transferring control to program entry point = %p", obj_main->entry);
757 /* Return the exit procedure and the program entry point. */
758 *exit_proc = rtld_exit;
760 return (func_ptr_type) obj_main->entry;
764 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
769 ptr = (void *)make_function_pointer(def, obj);
770 target = call_ifunc_resolver(ptr);
771 return ((void *)target);
775 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
776 * Changes to this function should be applied there as well.
779 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
783 const Obj_Entry *defobj;
786 RtldLockState lockstate;
788 rlock_acquire(rtld_bind_lock, &lockstate);
789 if (sigsetjmp(lockstate.env, 0) != 0)
790 lock_upgrade(rtld_bind_lock, &lockstate);
792 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
794 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
796 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
797 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
801 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
802 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
804 target = (Elf_Addr)(defobj->relocbase + def->st_value);
806 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
807 defobj->strtab + def->st_name, basename(obj->path),
808 (void *)target, basename(defobj->path));
811 * Write the new contents for the jmpslot. Note that depending on
812 * architecture, the value which we need to return back to the
813 * lazy binding trampoline may or may not be the target
814 * address. The value returned from reloc_jmpslot() is the value
815 * that the trampoline needs.
817 target = reloc_jmpslot(where, target, defobj, obj, rel);
818 lock_release(rtld_bind_lock, &lockstate);
823 * Error reporting function. Use it like printf. If formats the message
824 * into a buffer, and sets things up so that the next call to dlerror()
825 * will return the message.
828 _rtld_error(const char *fmt, ...)
830 static char buf[512];
834 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
837 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
841 * Return a dynamically-allocated copy of the current error message, if any.
846 return error_message == NULL ? NULL : xstrdup(error_message);
850 * Restore the current error message from a copy which was previously saved
851 * by errmsg_save(). The copy is freed.
854 errmsg_restore(char *saved_msg)
856 if (saved_msg == NULL)
857 error_message = NULL;
859 _rtld_error("%s", saved_msg);
865 basename(const char *name)
867 const char *p = strrchr(name, '/');
868 return p != NULL ? p + 1 : name;
871 static struct utsname uts;
874 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
875 const char *subst, bool may_free)
877 char *p, *p1, *res, *resp;
878 int subst_len, kw_len, subst_count, old_len, new_len;
883 * First, count the number of the keyword occurrences, to
884 * preallocate the final string.
886 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
893 * If the keyword is not found, just return.
895 * Return non-substituted string if resolution failed. We
896 * cannot do anything more reasonable, the failure mode of the
897 * caller is unresolved library anyway.
899 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
900 return (may_free ? real : xstrdup(real));
902 subst = obj->origin_path;
905 * There is indeed something to substitute. Calculate the
906 * length of the resulting string, and allocate it.
908 subst_len = strlen(subst);
909 old_len = strlen(real);
910 new_len = old_len + (subst_len - kw_len) * subst_count;
911 res = xmalloc(new_len + 1);
914 * Now, execute the substitution loop.
916 for (p = real, resp = res, *resp = '\0';;) {
919 /* Copy the prefix before keyword. */
920 memcpy(resp, p, p1 - p);
922 /* Keyword replacement. */
923 memcpy(resp, subst, subst_len);
931 /* Copy to the end of string and finish. */
939 origin_subst(Obj_Entry *obj, char *real)
941 char *res1, *res2, *res3, *res4;
943 if (obj == NULL || !trust)
944 return (xstrdup(real));
945 if (uts.sysname[0] == '\0') {
946 if (uname(&uts) != 0) {
947 _rtld_error("utsname failed: %d", errno);
951 res1 = origin_subst_one(obj, real, "$ORIGIN", NULL, false);
952 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
953 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
954 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
961 const char *msg = dlerror();
965 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
966 rtld_fdputstr(STDERR_FILENO, msg);
967 rtld_fdputchar(STDERR_FILENO, '\n');
972 * Process a shared object's DYNAMIC section, and save the important
973 * information in its Obj_Entry structure.
976 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
977 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
980 Needed_Entry **needed_tail = &obj->needed;
981 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
982 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
983 const Elf_Hashelt *hashtab;
984 const Elf32_Word *hashval;
985 Elf32_Word bkt, nmaskwords;
987 int plttype = DT_REL;
993 obj->bind_now = false;
994 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
995 switch (dynp->d_tag) {
998 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
1002 obj->relsize = dynp->d_un.d_val;
1006 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1010 obj->pltrel = (const Elf_Rel *)
1011 (obj->relocbase + dynp->d_un.d_ptr);
1015 obj->pltrelsize = dynp->d_un.d_val;
1019 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
1023 obj->relasize = dynp->d_un.d_val;
1027 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1031 plttype = dynp->d_un.d_val;
1032 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1036 obj->symtab = (const Elf_Sym *)
1037 (obj->relocbase + dynp->d_un.d_ptr);
1041 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1045 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
1049 obj->strsize = dynp->d_un.d_val;
1053 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
1058 obj->verneednum = dynp->d_un.d_val;
1062 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1067 obj->verdefnum = dynp->d_un.d_val;
1071 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1077 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1079 obj->nbuckets = hashtab[0];
1080 obj->nchains = hashtab[1];
1081 obj->buckets = hashtab + 2;
1082 obj->chains = obj->buckets + obj->nbuckets;
1083 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1084 obj->buckets != NULL;
1090 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1092 obj->nbuckets_gnu = hashtab[0];
1093 obj->symndx_gnu = hashtab[1];
1094 nmaskwords = hashtab[2];
1095 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1096 obj->maskwords_bm_gnu = nmaskwords - 1;
1097 obj->shift2_gnu = hashtab[3];
1098 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1099 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1100 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1102 /* Number of bitmask words is required to be power of 2 */
1103 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1104 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1110 Needed_Entry *nep = NEW(Needed_Entry);
1111 nep->name = dynp->d_un.d_val;
1116 needed_tail = &nep->next;
1122 Needed_Entry *nep = NEW(Needed_Entry);
1123 nep->name = dynp->d_un.d_val;
1127 *needed_filtees_tail = nep;
1128 needed_filtees_tail = &nep->next;
1134 Needed_Entry *nep = NEW(Needed_Entry);
1135 nep->name = dynp->d_un.d_val;
1139 *needed_aux_filtees_tail = nep;
1140 needed_aux_filtees_tail = &nep->next;
1145 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1149 obj->textrel = true;
1153 obj->symbolic = true;
1158 * We have to wait until later to process this, because we
1159 * might not have gotten the address of the string table yet.
1169 *dyn_runpath = dynp;
1173 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1176 case DT_PREINIT_ARRAY:
1177 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1180 case DT_PREINIT_ARRAYSZ:
1181 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1185 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1188 case DT_INIT_ARRAYSZ:
1189 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1193 obj->fini = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1197 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1200 case DT_FINI_ARRAYSZ:
1201 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1205 * Don't process DT_DEBUG on MIPS as the dynamic section
1206 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1212 dbg("Filling in DT_DEBUG entry");
1213 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1218 if (dynp->d_un.d_val & DF_ORIGIN)
1219 obj->z_origin = true;
1220 if (dynp->d_un.d_val & DF_SYMBOLIC)
1221 obj->symbolic = true;
1222 if (dynp->d_un.d_val & DF_TEXTREL)
1223 obj->textrel = true;
1224 if (dynp->d_un.d_val & DF_BIND_NOW)
1225 obj->bind_now = true;
1226 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1230 case DT_MIPS_LOCAL_GOTNO:
1231 obj->local_gotno = dynp->d_un.d_val;
1234 case DT_MIPS_SYMTABNO:
1235 obj->symtabno = dynp->d_un.d_val;
1238 case DT_MIPS_GOTSYM:
1239 obj->gotsym = dynp->d_un.d_val;
1242 case DT_MIPS_RLD_MAP:
1243 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1246 case DT_MIPS_PLTGOT:
1247 obj->mips_pltgot = (Elf_Addr *) (obj->relocbase +
1253 #ifdef __powerpc64__
1254 case DT_PPC64_GLINK:
1255 obj->glink = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1260 if (dynp->d_un.d_val & DF_1_NOOPEN)
1261 obj->z_noopen = true;
1262 if (dynp->d_un.d_val & DF_1_ORIGIN)
1263 obj->z_origin = true;
1264 if (dynp->d_un.d_val & DF_1_GLOBAL)
1265 obj->z_global = true;
1266 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1267 obj->bind_now = true;
1268 if (dynp->d_un.d_val & DF_1_NODELETE)
1269 obj->z_nodelete = true;
1270 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1271 obj->z_loadfltr = true;
1272 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1273 obj->z_interpose = true;
1274 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1275 obj->z_nodeflib = true;
1280 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1287 obj->traced = false;
1289 if (plttype == DT_RELA) {
1290 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1292 obj->pltrelasize = obj->pltrelsize;
1293 obj->pltrelsize = 0;
1296 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1297 if (obj->valid_hash_sysv)
1298 obj->dynsymcount = obj->nchains;
1299 else if (obj->valid_hash_gnu) {
1300 obj->dynsymcount = 0;
1301 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1302 if (obj->buckets_gnu[bkt] == 0)
1304 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1307 while ((*hashval++ & 1u) == 0);
1309 obj->dynsymcount += obj->symndx_gnu;
1314 obj_resolve_origin(Obj_Entry *obj)
1317 if (obj->origin_path != NULL)
1319 obj->origin_path = xmalloc(PATH_MAX);
1320 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1324 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1325 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1328 if (obj->z_origin && !obj_resolve_origin(obj))
1331 if (dyn_runpath != NULL) {
1332 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1333 obj->runpath = origin_subst(obj, obj->runpath);
1334 } else if (dyn_rpath != NULL) {
1335 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1336 obj->rpath = origin_subst(obj, obj->rpath);
1338 if (dyn_soname != NULL)
1339 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1343 digest_dynamic(Obj_Entry *obj, int early)
1345 const Elf_Dyn *dyn_rpath;
1346 const Elf_Dyn *dyn_soname;
1347 const Elf_Dyn *dyn_runpath;
1349 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1350 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1354 * Process a shared object's program header. This is used only for the
1355 * main program, when the kernel has already loaded the main program
1356 * into memory before calling the dynamic linker. It creates and
1357 * returns an Obj_Entry structure.
1360 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1363 const Elf_Phdr *phlimit = phdr + phnum;
1365 Elf_Addr note_start, note_end;
1369 for (ph = phdr; ph < phlimit; ph++) {
1370 if (ph->p_type != PT_PHDR)
1374 obj->phsize = ph->p_memsz;
1375 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1379 obj->stack_flags = PF_X | PF_R | PF_W;
1381 for (ph = phdr; ph < phlimit; ph++) {
1382 switch (ph->p_type) {
1385 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1389 if (nsegs == 0) { /* First load segment */
1390 obj->vaddrbase = trunc_page(ph->p_vaddr);
1391 obj->mapbase = obj->vaddrbase + obj->relocbase;
1392 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1394 } else { /* Last load segment */
1395 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1402 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1407 obj->tlssize = ph->p_memsz;
1408 obj->tlsalign = ph->p_align;
1409 obj->tlsinitsize = ph->p_filesz;
1410 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1414 obj->stack_flags = ph->p_flags;
1418 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1419 obj->relro_size = round_page(ph->p_memsz);
1423 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1424 note_end = note_start + ph->p_filesz;
1425 digest_notes(obj, note_start, note_end);
1430 _rtld_error("%s: too few PT_LOAD segments", path);
1439 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1441 const Elf_Note *note;
1442 const char *note_name;
1445 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1446 note = (const Elf_Note *)((const char *)(note + 1) +
1447 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1448 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1449 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1450 note->n_descsz != sizeof(int32_t))
1452 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1453 note->n_type != NT_FREEBSD_NOINIT_TAG)
1455 note_name = (const char *)(note + 1);
1456 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1457 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1459 switch (note->n_type) {
1460 case NT_FREEBSD_ABI_TAG:
1461 /* FreeBSD osrel note */
1462 p = (uintptr_t)(note + 1);
1463 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1464 obj->osrel = *(const int32_t *)(p);
1465 dbg("note osrel %d", obj->osrel);
1467 case NT_FREEBSD_NOINIT_TAG:
1468 /* FreeBSD 'crt does not call init' note */
1469 obj->crt_no_init = true;
1470 dbg("note crt_no_init");
1477 dlcheck(void *handle)
1481 TAILQ_FOREACH(obj, &obj_list, next) {
1482 if (obj == (Obj_Entry *) handle)
1486 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1487 _rtld_error("Invalid shared object handle %p", handle);
1494 * If the given object is already in the donelist, return true. Otherwise
1495 * add the object to the list and return false.
1498 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1502 for (i = 0; i < dlp->num_used; i++)
1503 if (dlp->objs[i] == obj)
1506 * Our donelist allocation should always be sufficient. But if
1507 * our threads locking isn't working properly, more shared objects
1508 * could have been loaded since we allocated the list. That should
1509 * never happen, but we'll handle it properly just in case it does.
1511 if (dlp->num_used < dlp->num_alloc)
1512 dlp->objs[dlp->num_used++] = obj;
1517 * Hash function for symbol table lookup. Don't even think about changing
1518 * this. It is specified by the System V ABI.
1521 elf_hash(const char *name)
1523 const unsigned char *p = (const unsigned char *) name;
1524 unsigned long h = 0;
1527 while (*p != '\0') {
1528 h = (h << 4) + *p++;
1529 if ((g = h & 0xf0000000) != 0)
1537 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1538 * unsigned in case it's implemented with a wider type.
1541 gnu_hash(const char *s)
1547 for (c = *s; c != '\0'; c = *++s)
1549 return (h & 0xffffffff);
1554 * Find the library with the given name, and return its full pathname.
1555 * The returned string is dynamically allocated. Generates an error
1556 * message and returns NULL if the library cannot be found.
1558 * If the second argument is non-NULL, then it refers to an already-
1559 * loaded shared object, whose library search path will be searched.
1561 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1562 * descriptor (which is close-on-exec) will be passed out via the third
1565 * The search order is:
1566 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1567 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1569 * DT_RUNPATH in the referencing file
1570 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1572 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1574 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1577 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1581 bool nodeflib, objgiven;
1583 objgiven = refobj != NULL;
1585 if (libmap_disable || !objgiven ||
1586 (name = lm_find(refobj->path, xname)) == NULL)
1587 name = (char *)xname;
1589 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1590 if (name[0] != '/' && !trust) {
1591 _rtld_error("Absolute pathname required "
1592 "for shared object \"%s\"", name);
1595 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1596 __DECONST(char *, name)));
1599 dbg(" Searching for \"%s\"", name);
1602 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1603 * back to pre-conforming behaviour if user requested so with
1604 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1607 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1608 pathname = search_library_path(name, ld_library_path, fdp);
1609 if (pathname != NULL)
1611 if (refobj != NULL) {
1612 pathname = search_library_path(name, refobj->rpath, fdp);
1613 if (pathname != NULL)
1616 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1617 if (pathname != NULL)
1619 pathname = search_library_path(name, gethints(false), fdp);
1620 if (pathname != NULL)
1622 pathname = search_library_path(name, ld_standard_library_path, fdp);
1623 if (pathname != NULL)
1626 nodeflib = objgiven ? refobj->z_nodeflib : false;
1628 pathname = search_library_path(name, refobj->rpath, fdp);
1629 if (pathname != NULL)
1632 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1633 pathname = search_library_path(name, obj_main->rpath, fdp);
1634 if (pathname != NULL)
1637 pathname = search_library_path(name, ld_library_path, fdp);
1638 if (pathname != NULL)
1641 pathname = search_library_path(name, refobj->runpath, fdp);
1642 if (pathname != NULL)
1645 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1646 if (pathname != NULL)
1648 pathname = search_library_path(name, gethints(nodeflib), fdp);
1649 if (pathname != NULL)
1651 if (objgiven && !nodeflib) {
1652 pathname = search_library_path(name,
1653 ld_standard_library_path, fdp);
1654 if (pathname != NULL)
1659 if (objgiven && refobj->path != NULL) {
1660 _rtld_error("Shared object \"%s\" not found, "
1661 "required by \"%s\"", name, basename(refobj->path));
1663 _rtld_error("Shared object \"%s\" not found", name);
1669 * Given a symbol number in a referencing object, find the corresponding
1670 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1671 * no definition was found. Returns a pointer to the Obj_Entry of the
1672 * defining object via the reference parameter DEFOBJ_OUT.
1675 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1676 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1677 RtldLockState *lockstate)
1681 const Obj_Entry *defobj;
1682 const Ver_Entry *ve;
1688 * If we have already found this symbol, get the information from
1691 if (symnum >= refobj->dynsymcount)
1692 return NULL; /* Bad object */
1693 if (cache != NULL && cache[symnum].sym != NULL) {
1694 *defobj_out = cache[symnum].obj;
1695 return cache[symnum].sym;
1698 ref = refobj->symtab + symnum;
1699 name = refobj->strtab + ref->st_name;
1705 * We don't have to do a full scale lookup if the symbol is local.
1706 * We know it will bind to the instance in this load module; to
1707 * which we already have a pointer (ie ref). By not doing a lookup,
1708 * we not only improve performance, but it also avoids unresolvable
1709 * symbols when local symbols are not in the hash table. This has
1710 * been seen with the ia64 toolchain.
1712 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1713 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1714 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1717 symlook_init(&req, name);
1719 ve = req.ventry = fetch_ventry(refobj, symnum);
1720 req.lockstate = lockstate;
1721 res = symlook_default(&req, refobj);
1724 defobj = req.defobj_out;
1732 * If we found no definition and the reference is weak, treat the
1733 * symbol as having the value zero.
1735 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1741 *defobj_out = defobj;
1742 /* Record the information in the cache to avoid subsequent lookups. */
1743 if (cache != NULL) {
1744 cache[symnum].sym = def;
1745 cache[symnum].obj = defobj;
1748 if (refobj != &obj_rtld)
1749 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1750 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1756 * Return the search path from the ldconfig hints file, reading it if
1757 * necessary. If nostdlib is true, then the default search paths are
1758 * not added to result.
1760 * Returns NULL if there are problems with the hints file,
1761 * or if the search path there is empty.
1764 gethints(bool nostdlib)
1766 static char *hints, *filtered_path;
1767 static struct elfhints_hdr hdr;
1768 struct fill_search_info_args sargs, hargs;
1769 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1770 struct dl_serpath *SLPpath, *hintpath;
1772 struct stat hint_stat;
1773 unsigned int SLPndx, hintndx, fndx, fcount;
1779 /* First call, read the hints file */
1780 if (hints == NULL) {
1781 /* Keep from trying again in case the hints file is bad. */
1784 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1788 * Check of hdr.dirlistlen value against type limit
1789 * intends to pacify static analyzers. Further
1790 * paranoia leads to checks that dirlist is fully
1791 * contained in the file range.
1793 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1794 hdr.magic != ELFHINTS_MAGIC ||
1795 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1796 fstat(fd, &hint_stat) == -1) {
1803 if (dl + hdr.dirlist < dl)
1806 if (dl + hdr.dirlistlen < dl)
1808 dl += hdr.dirlistlen;
1809 if (dl > hint_stat.st_size)
1811 p = xmalloc(hdr.dirlistlen + 1);
1812 if (pread(fd, p, hdr.dirlistlen + 1,
1813 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1814 p[hdr.dirlistlen] != '\0') {
1823 * If caller agreed to receive list which includes the default
1824 * paths, we are done. Otherwise, if we still did not
1825 * calculated filtered result, do it now.
1828 return (hints[0] != '\0' ? hints : NULL);
1829 if (filtered_path != NULL)
1833 * Obtain the list of all configured search paths, and the
1834 * list of the default paths.
1836 * First estimate the size of the results.
1838 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1840 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1843 sargs.request = RTLD_DI_SERINFOSIZE;
1844 sargs.serinfo = &smeta;
1845 hargs.request = RTLD_DI_SERINFOSIZE;
1846 hargs.serinfo = &hmeta;
1848 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1849 path_enumerate(hints, fill_search_info, &hargs);
1851 SLPinfo = xmalloc(smeta.dls_size);
1852 hintinfo = xmalloc(hmeta.dls_size);
1855 * Next fetch both sets of paths.
1857 sargs.request = RTLD_DI_SERINFO;
1858 sargs.serinfo = SLPinfo;
1859 sargs.serpath = &SLPinfo->dls_serpath[0];
1860 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1862 hargs.request = RTLD_DI_SERINFO;
1863 hargs.serinfo = hintinfo;
1864 hargs.serpath = &hintinfo->dls_serpath[0];
1865 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1867 path_enumerate(ld_standard_library_path, fill_search_info, &sargs);
1868 path_enumerate(hints, fill_search_info, &hargs);
1871 * Now calculate the difference between two sets, by excluding
1872 * standard paths from the full set.
1876 filtered_path = xmalloc(hdr.dirlistlen + 1);
1877 hintpath = &hintinfo->dls_serpath[0];
1878 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1880 SLPpath = &SLPinfo->dls_serpath[0];
1882 * Check each standard path against current.
1884 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1885 /* matched, skip the path */
1886 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1894 * Not matched against any standard path, add the path
1895 * to result. Separate consequtive paths with ':'.
1898 filtered_path[fndx] = ':';
1902 flen = strlen(hintpath->dls_name);
1903 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1906 filtered_path[fndx] = '\0';
1912 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1916 init_dag(Obj_Entry *root)
1918 const Needed_Entry *needed;
1919 const Objlist_Entry *elm;
1922 if (root->dag_inited)
1924 donelist_init(&donelist);
1926 /* Root object belongs to own DAG. */
1927 objlist_push_tail(&root->dldags, root);
1928 objlist_push_tail(&root->dagmembers, root);
1929 donelist_check(&donelist, root);
1932 * Add dependencies of root object to DAG in breadth order
1933 * by exploiting the fact that each new object get added
1934 * to the tail of the dagmembers list.
1936 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1937 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1938 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1940 objlist_push_tail(&needed->obj->dldags, root);
1941 objlist_push_tail(&root->dagmembers, needed->obj);
1944 root->dag_inited = true;
1948 init_marker(Obj_Entry *marker)
1951 bzero(marker, sizeof(*marker));
1952 marker->marker = true;
1956 globallist_curr(const Obj_Entry *obj)
1963 return (__DECONST(Obj_Entry *, obj));
1964 obj = TAILQ_PREV(obj, obj_entry_q, next);
1969 globallist_next(const Obj_Entry *obj)
1973 obj = TAILQ_NEXT(obj, next);
1977 return (__DECONST(Obj_Entry *, obj));
1981 /* Prevent the object from being unmapped while the bind lock is dropped. */
1983 hold_object(Obj_Entry *obj)
1990 unhold_object(Obj_Entry *obj)
1993 assert(obj->holdcount > 0);
1994 if (--obj->holdcount == 0 && obj->unholdfree)
1995 release_object(obj);
1999 process_z(Obj_Entry *root)
2001 const Objlist_Entry *elm;
2005 * Walk over object DAG and process every dependent object
2006 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2007 * to grow their own DAG.
2009 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2010 * symlook_global() to work.
2012 * For DF_1_NODELETE, the DAG should have its reference upped.
2014 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2018 if (obj->z_nodelete && !obj->ref_nodel) {
2019 dbg("obj %s -z nodelete", obj->path);
2022 obj->ref_nodel = true;
2024 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2025 dbg("obj %s -z global", obj->path);
2026 objlist_push_tail(&list_global, obj);
2032 * Initialize the dynamic linker. The argument is the address at which
2033 * the dynamic linker has been mapped into memory. The primary task of
2034 * this function is to relocate the dynamic linker.
2037 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2039 Obj_Entry objtmp; /* Temporary rtld object */
2040 const Elf_Ehdr *ehdr;
2041 const Elf_Dyn *dyn_rpath;
2042 const Elf_Dyn *dyn_soname;
2043 const Elf_Dyn *dyn_runpath;
2045 #ifdef RTLD_INIT_PAGESIZES_EARLY
2046 /* The page size is required by the dynamic memory allocator. */
2047 init_pagesizes(aux_info);
2051 * Conjure up an Obj_Entry structure for the dynamic linker.
2053 * The "path" member can't be initialized yet because string constants
2054 * cannot yet be accessed. Below we will set it correctly.
2056 memset(&objtmp, 0, sizeof(objtmp));
2059 objtmp.mapbase = mapbase;
2061 objtmp.relocbase = mapbase;
2064 objtmp.dynamic = rtld_dynamic(&objtmp);
2065 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2066 assert(objtmp.needed == NULL);
2067 #if !defined(__mips__)
2068 /* MIPS has a bogus DT_TEXTREL. */
2069 assert(!objtmp.textrel);
2072 * Temporarily put the dynamic linker entry into the object list, so
2073 * that symbols can be found.
2075 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2077 ehdr = (Elf_Ehdr *)mapbase;
2078 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2079 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2081 /* Initialize the object list. */
2082 TAILQ_INIT(&obj_list);
2084 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2085 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2087 #ifndef RTLD_INIT_PAGESIZES_EARLY
2088 /* The page size is required by the dynamic memory allocator. */
2089 init_pagesizes(aux_info);
2092 if (aux_info[AT_OSRELDATE] != NULL)
2093 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2095 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2097 /* Replace the path with a dynamically allocated copy. */
2098 obj_rtld.path = xstrdup(ld_path_rtld);
2100 r_debug.r_brk = r_debug_state;
2101 r_debug.r_state = RT_CONSISTENT;
2105 * Retrieve the array of supported page sizes. The kernel provides the page
2106 * sizes in increasing order.
2109 init_pagesizes(Elf_Auxinfo **aux_info)
2111 static size_t psa[MAXPAGESIZES];
2115 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2117 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2118 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2121 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2124 /* As a fallback, retrieve the base page size. */
2125 size = sizeof(psa[0]);
2126 if (aux_info[AT_PAGESZ] != NULL) {
2127 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2131 mib[1] = HW_PAGESIZE;
2135 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2136 _rtld_error("sysctl for hw.pagesize(s) failed");
2142 npagesizes = size / sizeof(pagesizes[0]);
2143 /* Discard any invalid entries at the end of the array. */
2144 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2149 * Add the init functions from a needed object list (and its recursive
2150 * needed objects) to "list". This is not used directly; it is a helper
2151 * function for initlist_add_objects(). The write lock must be held
2152 * when this function is called.
2155 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2157 /* Recursively process the successor needed objects. */
2158 if (needed->next != NULL)
2159 initlist_add_neededs(needed->next, list);
2161 /* Process the current needed object. */
2162 if (needed->obj != NULL)
2163 initlist_add_objects(needed->obj, needed->obj, list);
2167 * Scan all of the DAGs rooted in the range of objects from "obj" to
2168 * "tail" and add their init functions to "list". This recurses over
2169 * the DAGs and ensure the proper init ordering such that each object's
2170 * needed libraries are initialized before the object itself. At the
2171 * same time, this function adds the objects to the global finalization
2172 * list "list_fini" in the opposite order. The write lock must be
2173 * held when this function is called.
2176 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2180 if (obj->init_scanned || obj->init_done)
2182 obj->init_scanned = true;
2184 /* Recursively process the successor objects. */
2185 nobj = globallist_next(obj);
2186 if (nobj != NULL && obj != tail)
2187 initlist_add_objects(nobj, tail, list);
2189 /* Recursively process the needed objects. */
2190 if (obj->needed != NULL)
2191 initlist_add_neededs(obj->needed, list);
2192 if (obj->needed_filtees != NULL)
2193 initlist_add_neededs(obj->needed_filtees, list);
2194 if (obj->needed_aux_filtees != NULL)
2195 initlist_add_neededs(obj->needed_aux_filtees, list);
2197 /* Add the object to the init list. */
2198 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
2199 obj->init_array != (Elf_Addr)NULL)
2200 objlist_push_tail(list, obj);
2202 /* Add the object to the global fini list in the reverse order. */
2203 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2204 && !obj->on_fini_list) {
2205 objlist_push_head(&list_fini, obj);
2206 obj->on_fini_list = true;
2211 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2215 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2217 Needed_Entry *needed, *needed1;
2219 for (needed = n; needed != NULL; needed = needed->next) {
2220 if (needed->obj != NULL) {
2221 dlclose_locked(needed->obj, lockstate);
2225 for (needed = n; needed != NULL; needed = needed1) {
2226 needed1 = needed->next;
2232 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2235 free_needed_filtees(obj->needed_filtees, lockstate);
2236 obj->needed_filtees = NULL;
2237 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2238 obj->needed_aux_filtees = NULL;
2239 obj->filtees_loaded = false;
2243 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2244 RtldLockState *lockstate)
2247 for (; needed != NULL; needed = needed->next) {
2248 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2249 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2250 RTLD_LOCAL, lockstate);
2255 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2258 lock_restart_for_upgrade(lockstate);
2259 if (!obj->filtees_loaded) {
2260 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2261 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2262 obj->filtees_loaded = true;
2267 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2271 for (; needed != NULL; needed = needed->next) {
2272 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2273 flags & ~RTLD_LO_NOLOAD);
2274 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2281 * Given a shared object, traverse its list of needed objects, and load
2282 * each of them. Returns 0 on success. Generates an error message and
2283 * returns -1 on failure.
2286 load_needed_objects(Obj_Entry *first, int flags)
2290 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2293 if (process_needed(obj, obj->needed, flags) == -1)
2300 load_preload_objects(void)
2302 char *p = ld_preload;
2304 static const char delim[] = " \t:;";
2309 p += strspn(p, delim);
2310 while (*p != '\0') {
2311 size_t len = strcspn(p, delim);
2316 obj = load_object(p, -1, NULL, 0);
2318 return -1; /* XXX - cleanup */
2319 obj->z_interpose = true;
2322 p += strspn(p, delim);
2324 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2329 printable_path(const char *path)
2332 return (path == NULL ? "<unknown>" : path);
2336 * Load a shared object into memory, if it is not already loaded. The
2337 * object may be specified by name or by user-supplied file descriptor
2338 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2341 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2345 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2354 TAILQ_FOREACH(obj, &obj_list, next) {
2355 if (obj->marker || obj->doomed)
2357 if (object_match_name(obj, name))
2361 path = find_library(name, refobj, &fd);
2369 * search_library_pathfds() opens a fresh file descriptor for the
2370 * library, so there is no need to dup().
2372 } else if (fd_u == -1) {
2374 * If we didn't find a match by pathname, or the name is not
2375 * supplied, open the file and check again by device and inode.
2376 * This avoids false mismatches caused by multiple links or ".."
2379 * To avoid a race, we open the file and use fstat() rather than
2382 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2383 _rtld_error("Cannot open \"%s\"", path);
2388 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2390 _rtld_error("Cannot dup fd");
2395 if (fstat(fd, &sb) == -1) {
2396 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2401 TAILQ_FOREACH(obj, &obj_list, next) {
2402 if (obj->marker || obj->doomed)
2404 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2407 if (obj != NULL && name != NULL) {
2408 object_add_name(obj, name);
2413 if (flags & RTLD_LO_NOLOAD) {
2419 /* First use of this object, so we must map it in */
2420 obj = do_load_object(fd, name, path, &sb, flags);
2429 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2436 * but first, make sure that environment variables haven't been
2437 * used to circumvent the noexec flag on a filesystem.
2439 if (dangerous_ld_env) {
2440 if (fstatfs(fd, &fs) != 0) {
2441 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2444 if (fs.f_flags & MNT_NOEXEC) {
2445 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2449 dbg("loading \"%s\"", printable_path(path));
2450 obj = map_object(fd, printable_path(path), sbp);
2455 * If DT_SONAME is present in the object, digest_dynamic2 already
2456 * added it to the object names.
2459 object_add_name(obj, name);
2461 digest_dynamic(obj, 0);
2462 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2463 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2464 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2466 dbg("refusing to load non-loadable \"%s\"", obj->path);
2467 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2468 munmap(obj->mapbase, obj->mapsize);
2473 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2474 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2477 linkmap_add(obj); /* for GDB & dlinfo() */
2478 max_stack_flags |= obj->stack_flags;
2480 dbg(" %p .. %p: %s", obj->mapbase,
2481 obj->mapbase + obj->mapsize - 1, obj->path);
2483 dbg(" WARNING: %s has impure text", obj->path);
2484 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2491 obj_from_addr(const void *addr)
2495 TAILQ_FOREACH(obj, &obj_list, next) {
2498 if (addr < (void *) obj->mapbase)
2500 if (addr < (void *) (obj->mapbase + obj->mapsize))
2509 Elf_Addr *preinit_addr;
2512 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2513 if (preinit_addr == NULL)
2516 for (index = 0; index < obj_main->preinit_array_num; index++) {
2517 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2518 dbg("calling preinit function for %s at %p", obj_main->path,
2519 (void *)preinit_addr[index]);
2520 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2521 0, 0, obj_main->path);
2522 call_init_pointer(obj_main, preinit_addr[index]);
2528 * Call the finalization functions for each of the objects in "list"
2529 * belonging to the DAG of "root" and referenced once. If NULL "root"
2530 * is specified, every finalization function will be called regardless
2531 * of the reference count and the list elements won't be freed. All of
2532 * the objects are expected to have non-NULL fini functions.
2535 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2539 Elf_Addr *fini_addr;
2542 assert(root == NULL || root->refcount == 1);
2545 root->doomed = true;
2548 * Preserve the current error message since a fini function might
2549 * call into the dynamic linker and overwrite it.
2551 saved_msg = errmsg_save();
2553 STAILQ_FOREACH(elm, list, link) {
2554 if (root != NULL && (elm->obj->refcount != 1 ||
2555 objlist_find(&root->dagmembers, elm->obj) == NULL))
2557 /* Remove object from fini list to prevent recursive invocation. */
2558 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2559 /* Ensure that new references cannot be acquired. */
2560 elm->obj->doomed = true;
2562 hold_object(elm->obj);
2563 lock_release(rtld_bind_lock, lockstate);
2565 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2566 * When this happens, DT_FINI_ARRAY is processed first.
2568 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2569 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2570 for (index = elm->obj->fini_array_num - 1; index >= 0;
2572 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2573 dbg("calling fini function for %s at %p",
2574 elm->obj->path, (void *)fini_addr[index]);
2575 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2576 (void *)fini_addr[index], 0, 0, elm->obj->path);
2577 call_initfini_pointer(elm->obj, fini_addr[index]);
2581 if (elm->obj->fini != (Elf_Addr)NULL) {
2582 dbg("calling fini function for %s at %p", elm->obj->path,
2583 (void *)elm->obj->fini);
2584 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2585 0, 0, elm->obj->path);
2586 call_initfini_pointer(elm->obj, elm->obj->fini);
2588 wlock_acquire(rtld_bind_lock, lockstate);
2589 unhold_object(elm->obj);
2590 /* No need to free anything if process is going down. */
2594 * We must restart the list traversal after every fini call
2595 * because a dlclose() call from the fini function or from
2596 * another thread might have modified the reference counts.
2600 } while (elm != NULL);
2601 errmsg_restore(saved_msg);
2605 * Call the initialization functions for each of the objects in
2606 * "list". All of the objects are expected to have non-NULL init
2610 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2615 Elf_Addr *init_addr;
2619 * Clean init_scanned flag so that objects can be rechecked and
2620 * possibly initialized earlier if any of vectors called below
2621 * cause the change by using dlopen.
2623 TAILQ_FOREACH(obj, &obj_list, next) {
2626 obj->init_scanned = false;
2630 * Preserve the current error message since an init function might
2631 * call into the dynamic linker and overwrite it.
2633 saved_msg = errmsg_save();
2634 STAILQ_FOREACH(elm, list, link) {
2635 if (elm->obj->init_done) /* Initialized early. */
2638 * Race: other thread might try to use this object before current
2639 * one completes the initialization. Not much can be done here
2640 * without better locking.
2642 elm->obj->init_done = true;
2643 hold_object(elm->obj);
2644 lock_release(rtld_bind_lock, lockstate);
2647 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2648 * When this happens, DT_INIT is processed first.
2650 if (elm->obj->init != (Elf_Addr)NULL) {
2651 dbg("calling init function for %s at %p", elm->obj->path,
2652 (void *)elm->obj->init);
2653 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2654 0, 0, elm->obj->path);
2655 call_initfini_pointer(elm->obj, elm->obj->init);
2657 init_addr = (Elf_Addr *)elm->obj->init_array;
2658 if (init_addr != NULL) {
2659 for (index = 0; index < elm->obj->init_array_num; index++) {
2660 if (init_addr[index] != 0 && init_addr[index] != 1) {
2661 dbg("calling init function for %s at %p", elm->obj->path,
2662 (void *)init_addr[index]);
2663 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2664 (void *)init_addr[index], 0, 0, elm->obj->path);
2665 call_init_pointer(elm->obj, init_addr[index]);
2669 wlock_acquire(rtld_bind_lock, lockstate);
2670 unhold_object(elm->obj);
2672 errmsg_restore(saved_msg);
2676 objlist_clear(Objlist *list)
2680 while (!STAILQ_EMPTY(list)) {
2681 elm = STAILQ_FIRST(list);
2682 STAILQ_REMOVE_HEAD(list, link);
2687 static Objlist_Entry *
2688 objlist_find(Objlist *list, const Obj_Entry *obj)
2692 STAILQ_FOREACH(elm, list, link)
2693 if (elm->obj == obj)
2699 objlist_init(Objlist *list)
2705 objlist_push_head(Objlist *list, Obj_Entry *obj)
2709 elm = NEW(Objlist_Entry);
2711 STAILQ_INSERT_HEAD(list, elm, link);
2715 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2719 elm = NEW(Objlist_Entry);
2721 STAILQ_INSERT_TAIL(list, elm, link);
2725 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2727 Objlist_Entry *elm, *listelm;
2729 STAILQ_FOREACH(listelm, list, link) {
2730 if (listelm->obj == listobj)
2733 elm = NEW(Objlist_Entry);
2735 if (listelm != NULL)
2736 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2738 STAILQ_INSERT_TAIL(list, elm, link);
2742 objlist_remove(Objlist *list, Obj_Entry *obj)
2746 if ((elm = objlist_find(list, obj)) != NULL) {
2747 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2753 * Relocate dag rooted in the specified object.
2754 * Returns 0 on success, or -1 on failure.
2758 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2759 int flags, RtldLockState *lockstate)
2765 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2766 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2775 * Prepare for, or clean after, relocating an object marked with
2776 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2777 * segments are remapped read-write. After relocations are done, the
2778 * segment's permissions are returned back to the modes specified in
2779 * the phdrs. If any relocation happened, or always for wired
2780 * program, COW is triggered.
2783 reloc_textrel_prot(Obj_Entry *obj, bool before)
2790 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2792 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2794 base = obj->relocbase + trunc_page(ph->p_vaddr);
2795 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2796 trunc_page(ph->p_vaddr);
2797 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2798 if (mprotect(base, sz, prot) == -1) {
2799 _rtld_error("%s: Cannot write-%sable text segment: %s",
2800 obj->path, before ? "en" : "dis",
2801 rtld_strerror(errno));
2809 * Relocate single object.
2810 * Returns 0 on success, or -1 on failure.
2813 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2814 int flags, RtldLockState *lockstate)
2819 obj->relocated = true;
2821 dbg("relocating \"%s\"", obj->path);
2823 if (obj->symtab == NULL || obj->strtab == NULL ||
2824 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2825 _rtld_error("%s: Shared object has no run-time symbol table",
2830 /* There are relocations to the write-protected text segment. */
2831 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2834 /* Process the non-PLT non-IFUNC relocations. */
2835 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2838 /* Re-protected the text segment. */
2839 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2842 /* Set the special PLT or GOT entries. */
2845 /* Process the PLT relocations. */
2846 if (reloc_plt(obj) == -1)
2848 /* Relocate the jump slots if we are doing immediate binding. */
2849 if (obj->bind_now || bind_now)
2850 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2854 * Process the non-PLT IFUNC relocations. The relocations are
2855 * processed in two phases, because IFUNC resolvers may
2856 * reference other symbols, which must be readily processed
2857 * before resolvers are called.
2859 if (obj->non_plt_gnu_ifunc &&
2860 reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
2863 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2867 * Set up the magic number and version in the Obj_Entry. These
2868 * were checked in the crt1.o from the original ElfKit, so we
2869 * set them for backward compatibility.
2871 obj->magic = RTLD_MAGIC;
2872 obj->version = RTLD_VERSION;
2878 * Relocate newly-loaded shared objects. The argument is a pointer to
2879 * the Obj_Entry for the first such object. All objects from the first
2880 * to the end of the list of objects are relocated. Returns 0 on success,
2884 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2885 int flags, RtldLockState *lockstate)
2890 for (error = 0, obj = first; obj != NULL;
2891 obj = TAILQ_NEXT(obj, next)) {
2894 error = relocate_object(obj, bind_now, rtldobj, flags,
2903 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2904 * referencing STT_GNU_IFUNC symbols is postponed till the other
2905 * relocations are done. The indirect functions specified as
2906 * ifunc are allowed to call other symbols, so we need to have
2907 * objects relocated before asking for resolution from indirects.
2909 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2910 * instead of the usual lazy handling of PLT slots. It is
2911 * consistent with how GNU does it.
2914 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2915 RtldLockState *lockstate)
2917 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2919 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2920 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2926 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2927 RtldLockState *lockstate)
2931 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2934 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2941 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2942 RtldLockState *lockstate)
2946 STAILQ_FOREACH(elm, list, link) {
2947 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2955 * Cleanup procedure. It will be called (by the atexit mechanism) just
2956 * before the process exits.
2961 RtldLockState lockstate;
2963 wlock_acquire(rtld_bind_lock, &lockstate);
2965 objlist_call_fini(&list_fini, NULL, &lockstate);
2966 /* No need to remove the items from the list, since we are exiting. */
2967 if (!libmap_disable)
2969 lock_release(rtld_bind_lock, &lockstate);
2973 * Iterate over a search path, translate each element, and invoke the
2974 * callback on the result.
2977 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2983 path += strspn(path, ":;");
2984 while (*path != '\0') {
2988 len = strcspn(path, ":;");
2989 trans = lm_findn(NULL, path, len);
2991 res = callback(trans, strlen(trans), arg);
2993 res = callback(path, len, arg);
2999 path += strspn(path, ":;");
3005 struct try_library_args {
3014 try_library_path(const char *dir, size_t dirlen, void *param)
3016 struct try_library_args *arg;
3020 if (*dir == '/' || trust) {
3023 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3026 pathname = arg->buffer;
3027 strncpy(pathname, dir, dirlen);
3028 pathname[dirlen] = '/';
3029 strcpy(pathname + dirlen + 1, arg->name);
3031 dbg(" Trying \"%s\"", pathname);
3032 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3034 dbg(" Opened \"%s\", fd %d", pathname, fd);
3035 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3036 strcpy(pathname, arg->buffer);
3040 dbg(" Failed to open \"%s\": %s",
3041 pathname, rtld_strerror(errno));
3048 search_library_path(const char *name, const char *path, int *fdp)
3051 struct try_library_args arg;
3057 arg.namelen = strlen(name);
3058 arg.buffer = xmalloc(PATH_MAX);
3059 arg.buflen = PATH_MAX;
3062 p = path_enumerate(path, try_library_path, &arg);
3072 * Finds the library with the given name using the directory descriptors
3073 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3075 * Returns a freshly-opened close-on-exec file descriptor for the library,
3076 * or -1 if the library cannot be found.
3079 search_library_pathfds(const char *name, const char *path, int *fdp)
3081 char *envcopy, *fdstr, *found, *last_token;
3085 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3087 /* Don't load from user-specified libdirs into setuid binaries. */
3091 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3095 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3096 if (name[0] == '/') {
3097 dbg("Absolute path (%s) passed to %s", name, __func__);
3102 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3103 * copy of the path, as strtok_r rewrites separator tokens
3107 envcopy = xstrdup(path);
3108 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3109 fdstr = strtok_r(NULL, ":", &last_token)) {
3110 dirfd = parse_integer(fdstr);
3112 _rtld_error("failed to parse directory FD: '%s'",
3116 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3119 len = strlen(fdstr) + strlen(name) + 3;
3120 found = xmalloc(len);
3121 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3122 _rtld_error("error generating '%d/%s'",
3126 dbg("open('%s') => %d", found, fd);
3137 dlclose(void *handle)
3139 RtldLockState lockstate;
3142 wlock_acquire(rtld_bind_lock, &lockstate);
3143 error = dlclose_locked(handle, &lockstate);
3144 lock_release(rtld_bind_lock, &lockstate);
3149 dlclose_locked(void *handle, RtldLockState *lockstate)
3153 root = dlcheck(handle);
3156 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3159 /* Unreference the object and its dependencies. */
3160 root->dl_refcount--;
3162 if (root->refcount == 1) {
3164 * The object will be no longer referenced, so we must unload it.
3165 * First, call the fini functions.
3167 objlist_call_fini(&list_fini, root, lockstate);
3171 /* Finish cleaning up the newly-unreferenced objects. */
3172 GDB_STATE(RT_DELETE,&root->linkmap);
3173 unload_object(root, lockstate);
3174 GDB_STATE(RT_CONSISTENT,NULL);
3178 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3185 char *msg = error_message;
3186 error_message = NULL;
3191 * This function is deprecated and has no effect.
3194 dllockinit(void *context,
3195 void *(*lock_create)(void *context),
3196 void (*rlock_acquire)(void *lock),
3197 void (*wlock_acquire)(void *lock),
3198 void (*lock_release)(void *lock),
3199 void (*lock_destroy)(void *lock),
3200 void (*context_destroy)(void *context))
3202 static void *cur_context;
3203 static void (*cur_context_destroy)(void *);
3205 /* Just destroy the context from the previous call, if necessary. */
3206 if (cur_context_destroy != NULL)
3207 cur_context_destroy(cur_context);
3208 cur_context = context;
3209 cur_context_destroy = context_destroy;
3213 dlopen(const char *name, int mode)
3216 return (rtld_dlopen(name, -1, mode));
3220 fdlopen(int fd, int mode)
3223 return (rtld_dlopen(NULL, fd, mode));
3227 rtld_dlopen(const char *name, int fd, int mode)
3229 RtldLockState lockstate;
3232 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3233 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3234 if (ld_tracing != NULL) {
3235 rlock_acquire(rtld_bind_lock, &lockstate);
3236 if (sigsetjmp(lockstate.env, 0) != 0)
3237 lock_upgrade(rtld_bind_lock, &lockstate);
3238 environ = (char **)*get_program_var_addr("environ", &lockstate);
3239 lock_release(rtld_bind_lock, &lockstate);
3241 lo_flags = RTLD_LO_DLOPEN;
3242 if (mode & RTLD_NODELETE)
3243 lo_flags |= RTLD_LO_NODELETE;
3244 if (mode & RTLD_NOLOAD)
3245 lo_flags |= RTLD_LO_NOLOAD;
3246 if (ld_tracing != NULL)
3247 lo_flags |= RTLD_LO_TRACE;
3249 return (dlopen_object(name, fd, obj_main, lo_flags,
3250 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3254 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3259 if (obj->refcount == 0)
3260 unload_object(obj, lockstate);
3264 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3265 int mode, RtldLockState *lockstate)
3267 Obj_Entry *old_obj_tail;
3270 RtldLockState mlockstate;
3273 objlist_init(&initlist);
3275 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3276 wlock_acquire(rtld_bind_lock, &mlockstate);
3277 lockstate = &mlockstate;
3279 GDB_STATE(RT_ADD,NULL);
3281 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3283 if (name == NULL && fd == -1) {
3287 obj = load_object(name, fd, refobj, lo_flags);
3292 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3293 objlist_push_tail(&list_global, obj);
3294 if (globallist_next(old_obj_tail) != NULL) {
3295 /* We loaded something new. */
3296 assert(globallist_next(old_obj_tail) == obj);
3297 result = load_needed_objects(obj,
3298 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
3302 result = rtld_verify_versions(&obj->dagmembers);
3303 if (result != -1 && ld_tracing)
3305 if (result == -1 || relocate_object_dag(obj,
3306 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3307 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3309 dlopen_cleanup(obj, lockstate);
3311 } else if (lo_flags & RTLD_LO_EARLY) {
3313 * Do not call the init functions for early loaded
3314 * filtees. The image is still not initialized enough
3317 * Our object is found by the global object list and
3318 * will be ordered among all init calls done right
3319 * before transferring control to main.
3322 /* Make list of init functions to call. */
3323 initlist_add_objects(obj, obj, &initlist);
3326 * Process all no_delete or global objects here, given
3327 * them own DAGs to prevent their dependencies from being
3328 * unloaded. This has to be done after we have loaded all
3329 * of the dependencies, so that we do not miss any.
3335 * Bump the reference counts for objects on this DAG. If
3336 * this is the first dlopen() call for the object that was
3337 * already loaded as a dependency, initialize the dag
3343 if ((lo_flags & RTLD_LO_TRACE) != 0)
3346 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3347 obj->z_nodelete) && !obj->ref_nodel) {
3348 dbg("obj %s nodelete", obj->path);
3350 obj->z_nodelete = obj->ref_nodel = true;
3354 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3356 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3358 if (!(lo_flags & RTLD_LO_EARLY)) {
3359 map_stacks_exec(lockstate);
3362 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3363 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3365 objlist_clear(&initlist);
3366 dlopen_cleanup(obj, lockstate);
3367 if (lockstate == &mlockstate)
3368 lock_release(rtld_bind_lock, lockstate);
3372 if (!(lo_flags & RTLD_LO_EARLY)) {
3373 /* Call the init functions. */
3374 objlist_call_init(&initlist, lockstate);
3376 objlist_clear(&initlist);
3377 if (lockstate == &mlockstate)
3378 lock_release(rtld_bind_lock, lockstate);
3381 trace_loaded_objects(obj);
3382 if (lockstate == &mlockstate)
3383 lock_release(rtld_bind_lock, lockstate);
3388 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3392 const Obj_Entry *obj, *defobj;
3395 RtldLockState lockstate;
3402 symlook_init(&req, name);
3404 req.flags = flags | SYMLOOK_IN_PLT;
3405 req.lockstate = &lockstate;
3407 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3408 rlock_acquire(rtld_bind_lock, &lockstate);
3409 if (sigsetjmp(lockstate.env, 0) != 0)
3410 lock_upgrade(rtld_bind_lock, &lockstate);
3411 if (handle == NULL || handle == RTLD_NEXT ||
3412 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3414 if ((obj = obj_from_addr(retaddr)) == NULL) {
3415 _rtld_error("Cannot determine caller's shared object");
3416 lock_release(rtld_bind_lock, &lockstate);
3417 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3420 if (handle == NULL) { /* Just the caller's shared object. */
3421 res = symlook_obj(&req, obj);
3424 defobj = req.defobj_out;
3426 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3427 handle == RTLD_SELF) { /* ... caller included */
3428 if (handle == RTLD_NEXT)
3429 obj = globallist_next(obj);
3430 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3433 res = symlook_obj(&req, obj);
3436 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3438 defobj = req.defobj_out;
3439 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3445 * Search the dynamic linker itself, and possibly resolve the
3446 * symbol from there. This is how the application links to
3447 * dynamic linker services such as dlopen.
3449 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3450 res = symlook_obj(&req, &obj_rtld);
3453 defobj = req.defobj_out;
3457 assert(handle == RTLD_DEFAULT);
3458 res = symlook_default(&req, obj);
3460 defobj = req.defobj_out;
3465 if ((obj = dlcheck(handle)) == NULL) {
3466 lock_release(rtld_bind_lock, &lockstate);
3467 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3471 donelist_init(&donelist);
3472 if (obj->mainprog) {
3473 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3474 res = symlook_global(&req, &donelist);
3477 defobj = req.defobj_out;
3480 * Search the dynamic linker itself, and possibly resolve the
3481 * symbol from there. This is how the application links to
3482 * dynamic linker services such as dlopen.
3484 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3485 res = symlook_obj(&req, &obj_rtld);
3488 defobj = req.defobj_out;
3493 /* Search the whole DAG rooted at the given object. */
3494 res = symlook_list(&req, &obj->dagmembers, &donelist);
3497 defobj = req.defobj_out;
3503 lock_release(rtld_bind_lock, &lockstate);
3506 * The value required by the caller is derived from the value
3507 * of the symbol. this is simply the relocated value of the
3510 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3511 sym = make_function_pointer(def, defobj);
3512 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3513 sym = rtld_resolve_ifunc(defobj, def);
3514 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3515 ti.ti_module = defobj->tlsindex;
3516 ti.ti_offset = def->st_value;
3517 sym = __tls_get_addr(&ti);
3519 sym = defobj->relocbase + def->st_value;
3520 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3524 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3525 ve != NULL ? ve->name : "");
3526 lock_release(rtld_bind_lock, &lockstate);
3527 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3532 dlsym(void *handle, const char *name)
3534 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3539 dlfunc(void *handle, const char *name)
3546 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3552 dlvsym(void *handle, const char *name, const char *version)
3556 ventry.name = version;
3558 ventry.hash = elf_hash(version);
3560 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3565 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3567 const Obj_Entry *obj;
3568 RtldLockState lockstate;
3570 rlock_acquire(rtld_bind_lock, &lockstate);
3571 obj = obj_from_addr(addr);
3573 _rtld_error("No shared object contains address");
3574 lock_release(rtld_bind_lock, &lockstate);
3577 rtld_fill_dl_phdr_info(obj, phdr_info);
3578 lock_release(rtld_bind_lock, &lockstate);
3583 dladdr(const void *addr, Dl_info *info)
3585 const Obj_Entry *obj;
3588 unsigned long symoffset;
3589 RtldLockState lockstate;
3591 rlock_acquire(rtld_bind_lock, &lockstate);
3592 obj = obj_from_addr(addr);
3594 _rtld_error("No shared object contains address");
3595 lock_release(rtld_bind_lock, &lockstate);
3598 info->dli_fname = obj->path;
3599 info->dli_fbase = obj->mapbase;
3600 info->dli_saddr = (void *)0;
3601 info->dli_sname = NULL;
3604 * Walk the symbol list looking for the symbol whose address is
3605 * closest to the address sent in.
3607 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3608 def = obj->symtab + symoffset;
3611 * For skip the symbol if st_shndx is either SHN_UNDEF or
3614 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3618 * If the symbol is greater than the specified address, or if it
3619 * is further away from addr than the current nearest symbol,
3622 symbol_addr = obj->relocbase + def->st_value;
3623 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3626 /* Update our idea of the nearest symbol. */
3627 info->dli_sname = obj->strtab + def->st_name;
3628 info->dli_saddr = symbol_addr;
3631 if (info->dli_saddr == addr)
3634 lock_release(rtld_bind_lock, &lockstate);
3639 dlinfo(void *handle, int request, void *p)
3641 const Obj_Entry *obj;
3642 RtldLockState lockstate;
3645 rlock_acquire(rtld_bind_lock, &lockstate);
3647 if (handle == NULL || handle == RTLD_SELF) {
3650 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3651 if ((obj = obj_from_addr(retaddr)) == NULL)
3652 _rtld_error("Cannot determine caller's shared object");
3654 obj = dlcheck(handle);
3657 lock_release(rtld_bind_lock, &lockstate);
3663 case RTLD_DI_LINKMAP:
3664 *((struct link_map const **)p) = &obj->linkmap;
3666 case RTLD_DI_ORIGIN:
3667 error = rtld_dirname(obj->path, p);
3670 case RTLD_DI_SERINFOSIZE:
3671 case RTLD_DI_SERINFO:
3672 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3676 _rtld_error("Invalid request %d passed to dlinfo()", request);
3680 lock_release(rtld_bind_lock, &lockstate);
3686 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3689 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3690 phdr_info->dlpi_name = obj->path;
3691 phdr_info->dlpi_phdr = obj->phdr;
3692 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3693 phdr_info->dlpi_tls_modid = obj->tlsindex;
3694 phdr_info->dlpi_tls_data = obj->tlsinit;
3695 phdr_info->dlpi_adds = obj_loads;
3696 phdr_info->dlpi_subs = obj_loads - obj_count;
3700 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3702 struct dl_phdr_info phdr_info;
3703 Obj_Entry *obj, marker;
3704 RtldLockState bind_lockstate, phdr_lockstate;
3707 init_marker(&marker);
3710 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3711 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3712 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3713 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3714 rtld_fill_dl_phdr_info(obj, &phdr_info);
3716 lock_release(rtld_bind_lock, &bind_lockstate);
3718 error = callback(&phdr_info, sizeof phdr_info, param);
3720 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3722 obj = globallist_next(&marker);
3723 TAILQ_REMOVE(&obj_list, &marker, next);
3725 lock_release(rtld_bind_lock, &bind_lockstate);
3726 lock_release(rtld_phdr_lock, &phdr_lockstate);
3732 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3733 lock_release(rtld_bind_lock, &bind_lockstate);
3734 error = callback(&phdr_info, sizeof(phdr_info), param);
3736 lock_release(rtld_phdr_lock, &phdr_lockstate);
3741 fill_search_info(const char *dir, size_t dirlen, void *param)
3743 struct fill_search_info_args *arg;
3747 if (arg->request == RTLD_DI_SERINFOSIZE) {
3748 arg->serinfo->dls_cnt ++;
3749 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3751 struct dl_serpath *s_entry;
3753 s_entry = arg->serpath;
3754 s_entry->dls_name = arg->strspace;
3755 s_entry->dls_flags = arg->flags;
3757 strncpy(arg->strspace, dir, dirlen);
3758 arg->strspace[dirlen] = '\0';
3760 arg->strspace += dirlen + 1;
3768 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3770 struct dl_serinfo _info;
3771 struct fill_search_info_args args;
3773 args.request = RTLD_DI_SERINFOSIZE;
3774 args.serinfo = &_info;
3776 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3779 path_enumerate(obj->rpath, fill_search_info, &args);
3780 path_enumerate(ld_library_path, fill_search_info, &args);
3781 path_enumerate(obj->runpath, fill_search_info, &args);
3782 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3783 if (!obj->z_nodeflib)
3784 path_enumerate(ld_standard_library_path, fill_search_info, &args);
3787 if (request == RTLD_DI_SERINFOSIZE) {
3788 info->dls_size = _info.dls_size;
3789 info->dls_cnt = _info.dls_cnt;
3793 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3794 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3798 args.request = RTLD_DI_SERINFO;
3799 args.serinfo = info;
3800 args.serpath = &info->dls_serpath[0];
3801 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3803 args.flags = LA_SER_RUNPATH;
3804 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3807 args.flags = LA_SER_LIBPATH;
3808 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3811 args.flags = LA_SER_RUNPATH;
3812 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3815 args.flags = LA_SER_CONFIG;
3816 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3820 args.flags = LA_SER_DEFAULT;
3821 if (!obj->z_nodeflib &&
3822 path_enumerate(ld_standard_library_path, fill_search_info, &args) != NULL)
3828 rtld_dirname(const char *path, char *bname)
3832 /* Empty or NULL string gets treated as "." */
3833 if (path == NULL || *path == '\0') {
3839 /* Strip trailing slashes */
3840 endp = path + strlen(path) - 1;
3841 while (endp > path && *endp == '/')
3844 /* Find the start of the dir */
3845 while (endp > path && *endp != '/')
3848 /* Either the dir is "/" or there are no slashes */
3850 bname[0] = *endp == '/' ? '/' : '.';
3856 } while (endp > path && *endp == '/');
3859 if (endp - path + 2 > PATH_MAX)
3861 _rtld_error("Filename is too long: %s", path);
3865 strncpy(bname, path, endp - path + 1);
3866 bname[endp - path + 1] = '\0';
3871 rtld_dirname_abs(const char *path, char *base)
3875 if (realpath(path, base) == NULL)
3877 dbg("%s -> %s", path, base);
3878 last = strrchr(base, '/');
3887 linkmap_add(Obj_Entry *obj)
3889 struct link_map *l = &obj->linkmap;
3890 struct link_map *prev;
3892 obj->linkmap.l_name = obj->path;
3893 obj->linkmap.l_addr = obj->mapbase;
3894 obj->linkmap.l_ld = obj->dynamic;
3896 /* GDB needs load offset on MIPS to use the symbols */
3897 obj->linkmap.l_offs = obj->relocbase;
3900 if (r_debug.r_map == NULL) {
3906 * Scan to the end of the list, but not past the entry for the
3907 * dynamic linker, which we want to keep at the very end.
3909 for (prev = r_debug.r_map;
3910 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3911 prev = prev->l_next)
3914 /* Link in the new entry. */
3916 l->l_next = prev->l_next;
3917 if (l->l_next != NULL)
3918 l->l_next->l_prev = l;
3923 linkmap_delete(Obj_Entry *obj)
3925 struct link_map *l = &obj->linkmap;
3927 if (l->l_prev == NULL) {
3928 if ((r_debug.r_map = l->l_next) != NULL)
3929 l->l_next->l_prev = NULL;
3933 if ((l->l_prev->l_next = l->l_next) != NULL)
3934 l->l_next->l_prev = l->l_prev;
3938 * Function for the debugger to set a breakpoint on to gain control.
3940 * The two parameters allow the debugger to easily find and determine
3941 * what the runtime loader is doing and to whom it is doing it.
3943 * When the loadhook trap is hit (r_debug_state, set at program
3944 * initialization), the arguments can be found on the stack:
3946 * +8 struct link_map *m
3947 * +4 struct r_debug *rd
3951 r_debug_state(struct r_debug* rd, struct link_map *m)
3954 * The following is a hack to force the compiler to emit calls to
3955 * this function, even when optimizing. If the function is empty,
3956 * the compiler is not obliged to emit any code for calls to it,
3957 * even when marked __noinline. However, gdb depends on those
3960 __compiler_membar();
3964 * A function called after init routines have completed. This can be used to
3965 * break before a program's entry routine is called, and can be used when
3966 * main is not available in the symbol table.
3969 _r_debug_postinit(struct link_map *m)
3972 /* See r_debug_state(). */
3973 __compiler_membar();
3977 release_object(Obj_Entry *obj)
3980 if (obj->holdcount > 0) {
3981 obj->unholdfree = true;
3984 munmap(obj->mapbase, obj->mapsize);
3985 linkmap_delete(obj);
3990 * Get address of the pointer variable in the main program.
3991 * Prefer non-weak symbol over the weak one.
3993 static const void **
3994 get_program_var_addr(const char *name, RtldLockState *lockstate)
3999 symlook_init(&req, name);
4000 req.lockstate = lockstate;
4001 donelist_init(&donelist);
4002 if (symlook_global(&req, &donelist) != 0)
4004 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4005 return ((const void **)make_function_pointer(req.sym_out,
4007 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4008 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4010 return ((const void **)(req.defobj_out->relocbase +
4011 req.sym_out->st_value));
4015 * Set a pointer variable in the main program to the given value. This
4016 * is used to set key variables such as "environ" before any of the
4017 * init functions are called.
4020 set_program_var(const char *name, const void *value)
4024 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4025 dbg("\"%s\": *%p <-- %p", name, addr, value);
4031 * Search the global objects, including dependencies and main object,
4032 * for the given symbol.
4035 symlook_global(SymLook *req, DoneList *donelist)
4038 const Objlist_Entry *elm;
4041 symlook_init_from_req(&req1, req);
4043 /* Search all objects loaded at program start up. */
4044 if (req->defobj_out == NULL ||
4045 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4046 res = symlook_list(&req1, &list_main, donelist);
4047 if (res == 0 && (req->defobj_out == NULL ||
4048 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4049 req->sym_out = req1.sym_out;
4050 req->defobj_out = req1.defobj_out;
4051 assert(req->defobj_out != NULL);
4055 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4056 STAILQ_FOREACH(elm, &list_global, link) {
4057 if (req->defobj_out != NULL &&
4058 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4060 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4061 if (res == 0 && (req->defobj_out == NULL ||
4062 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4063 req->sym_out = req1.sym_out;
4064 req->defobj_out = req1.defobj_out;
4065 assert(req->defobj_out != NULL);
4069 return (req->sym_out != NULL ? 0 : ESRCH);
4073 * Given a symbol name in a referencing object, find the corresponding
4074 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4075 * no definition was found. Returns a pointer to the Obj_Entry of the
4076 * defining object via the reference parameter DEFOBJ_OUT.
4079 symlook_default(SymLook *req, const Obj_Entry *refobj)
4082 const Objlist_Entry *elm;
4086 donelist_init(&donelist);
4087 symlook_init_from_req(&req1, req);
4090 * Look first in the referencing object if linked symbolically,
4091 * and similarly handle protected symbols.
4093 res = symlook_obj(&req1, refobj);
4094 if (res == 0 && (refobj->symbolic ||
4095 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4096 req->sym_out = req1.sym_out;
4097 req->defobj_out = req1.defobj_out;
4098 assert(req->defobj_out != NULL);
4100 if (refobj->symbolic || req->defobj_out != NULL)
4101 donelist_check(&donelist, refobj);
4103 symlook_global(req, &donelist);
4105 /* Search all dlopened DAGs containing the referencing object. */
4106 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4107 if (req->sym_out != NULL &&
4108 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4110 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4111 if (res == 0 && (req->sym_out == NULL ||
4112 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4113 req->sym_out = req1.sym_out;
4114 req->defobj_out = req1.defobj_out;
4115 assert(req->defobj_out != NULL);
4120 * Search the dynamic linker itself, and possibly resolve the
4121 * symbol from there. This is how the application links to
4122 * dynamic linker services such as dlopen.
4124 if (req->sym_out == NULL ||
4125 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4126 res = symlook_obj(&req1, &obj_rtld);
4128 req->sym_out = req1.sym_out;
4129 req->defobj_out = req1.defobj_out;
4130 assert(req->defobj_out != NULL);
4134 return (req->sym_out != NULL ? 0 : ESRCH);
4138 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4141 const Obj_Entry *defobj;
4142 const Objlist_Entry *elm;
4148 STAILQ_FOREACH(elm, objlist, link) {
4149 if (donelist_check(dlp, elm->obj))
4151 symlook_init_from_req(&req1, req);
4152 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4153 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4155 defobj = req1.defobj_out;
4156 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4163 req->defobj_out = defobj;
4170 * Search the chain of DAGS cointed to by the given Needed_Entry
4171 * for a symbol of the given name. Each DAG is scanned completely
4172 * before advancing to the next one. Returns a pointer to the symbol,
4173 * or NULL if no definition was found.
4176 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4179 const Needed_Entry *n;
4180 const Obj_Entry *defobj;
4186 symlook_init_from_req(&req1, req);
4187 for (n = needed; n != NULL; n = n->next) {
4188 if (n->obj == NULL ||
4189 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4191 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4193 defobj = req1.defobj_out;
4194 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4200 req->defobj_out = defobj;
4207 * Search the symbol table of a single shared object for a symbol of
4208 * the given name and version, if requested. Returns a pointer to the
4209 * symbol, or NULL if no definition was found. If the object is
4210 * filter, return filtered symbol from filtee.
4212 * The symbol's hash value is passed in for efficiency reasons; that
4213 * eliminates many recomputations of the hash value.
4216 symlook_obj(SymLook *req, const Obj_Entry *obj)
4220 int flags, res, mres;
4223 * If there is at least one valid hash at this point, we prefer to
4224 * use the faster GNU version if available.
4226 if (obj->valid_hash_gnu)
4227 mres = symlook_obj1_gnu(req, obj);
4228 else if (obj->valid_hash_sysv)
4229 mres = symlook_obj1_sysv(req, obj);
4234 if (obj->needed_filtees != NULL) {
4235 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4236 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4237 donelist_init(&donelist);
4238 symlook_init_from_req(&req1, req);
4239 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4241 req->sym_out = req1.sym_out;
4242 req->defobj_out = req1.defobj_out;
4246 if (obj->needed_aux_filtees != NULL) {
4247 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4248 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4249 donelist_init(&donelist);
4250 symlook_init_from_req(&req1, req);
4251 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4253 req->sym_out = req1.sym_out;
4254 req->defobj_out = req1.defobj_out;
4262 /* Symbol match routine common to both hash functions */
4264 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4265 const unsigned long symnum)
4268 const Elf_Sym *symp;
4271 symp = obj->symtab + symnum;
4272 strp = obj->strtab + symp->st_name;
4274 switch (ELF_ST_TYPE(symp->st_info)) {
4280 if (symp->st_value == 0)
4284 if (symp->st_shndx != SHN_UNDEF)
4287 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4288 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4295 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4298 if (req->ventry == NULL) {
4299 if (obj->versyms != NULL) {
4300 verndx = VER_NDX(obj->versyms[symnum]);
4301 if (verndx > obj->vernum) {
4303 "%s: symbol %s references wrong version %d",
4304 obj->path, obj->strtab + symnum, verndx);
4308 * If we are not called from dlsym (i.e. this
4309 * is a normal relocation from unversioned
4310 * binary), accept the symbol immediately if
4311 * it happens to have first version after this
4312 * shared object became versioned. Otherwise,
4313 * if symbol is versioned and not hidden,
4314 * remember it. If it is the only symbol with
4315 * this name exported by the shared object, it
4316 * will be returned as a match by the calling
4317 * function. If symbol is global (verndx < 2)
4318 * accept it unconditionally.
4320 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4321 verndx == VER_NDX_GIVEN) {
4322 result->sym_out = symp;
4325 else if (verndx >= VER_NDX_GIVEN) {
4326 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4328 if (result->vsymp == NULL)
4329 result->vsymp = symp;
4335 result->sym_out = symp;
4338 if (obj->versyms == NULL) {
4339 if (object_match_name(obj, req->ventry->name)) {
4340 _rtld_error("%s: object %s should provide version %s "
4341 "for symbol %s", obj_rtld.path, obj->path,
4342 req->ventry->name, obj->strtab + symnum);
4346 verndx = VER_NDX(obj->versyms[symnum]);
4347 if (verndx > obj->vernum) {
4348 _rtld_error("%s: symbol %s references wrong version %d",
4349 obj->path, obj->strtab + symnum, verndx);
4352 if (obj->vertab[verndx].hash != req->ventry->hash ||
4353 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4355 * Version does not match. Look if this is a
4356 * global symbol and if it is not hidden. If
4357 * global symbol (verndx < 2) is available,
4358 * use it. Do not return symbol if we are
4359 * called by dlvsym, because dlvsym looks for
4360 * a specific version and default one is not
4361 * what dlvsym wants.
4363 if ((req->flags & SYMLOOK_DLSYM) ||
4364 (verndx >= VER_NDX_GIVEN) ||
4365 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4369 result->sym_out = symp;
4374 * Search for symbol using SysV hash function.
4375 * obj->buckets is known not to be NULL at this point; the test for this was
4376 * performed with the obj->valid_hash_sysv assignment.
4379 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4381 unsigned long symnum;
4382 Sym_Match_Result matchres;
4384 matchres.sym_out = NULL;
4385 matchres.vsymp = NULL;
4386 matchres.vcount = 0;
4388 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4389 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4390 if (symnum >= obj->nchains)
4391 return (ESRCH); /* Bad object */
4393 if (matched_symbol(req, obj, &matchres, symnum)) {
4394 req->sym_out = matchres.sym_out;
4395 req->defobj_out = obj;
4399 if (matchres.vcount == 1) {
4400 req->sym_out = matchres.vsymp;
4401 req->defobj_out = obj;
4407 /* Search for symbol using GNU hash function */
4409 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4411 Elf_Addr bloom_word;
4412 const Elf32_Word *hashval;
4414 Sym_Match_Result matchres;
4415 unsigned int h1, h2;
4416 unsigned long symnum;
4418 matchres.sym_out = NULL;
4419 matchres.vsymp = NULL;
4420 matchres.vcount = 0;
4422 /* Pick right bitmask word from Bloom filter array */
4423 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4424 obj->maskwords_bm_gnu];
4426 /* Calculate modulus word size of gnu hash and its derivative */
4427 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4428 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4430 /* Filter out the "definitely not in set" queries */
4431 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4434 /* Locate hash chain and corresponding value element*/
4435 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4438 hashval = &obj->chain_zero_gnu[bucket];
4440 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4441 symnum = hashval - obj->chain_zero_gnu;
4442 if (matched_symbol(req, obj, &matchres, symnum)) {
4443 req->sym_out = matchres.sym_out;
4444 req->defobj_out = obj;
4448 } while ((*hashval++ & 1) == 0);
4449 if (matchres.vcount == 1) {
4450 req->sym_out = matchres.vsymp;
4451 req->defobj_out = obj;
4458 trace_loaded_objects(Obj_Entry *obj)
4460 char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4463 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4466 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4467 fmt1 = "\t%o => %p (%x)\n";
4469 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4470 fmt2 = "\t%o (%x)\n";
4472 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4474 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4475 Needed_Entry *needed;
4481 if (list_containers && obj->needed != NULL)
4482 rtld_printf("%s:\n", obj->path);
4483 for (needed = obj->needed; needed; needed = needed->next) {
4484 if (needed->obj != NULL) {
4485 if (needed->obj->traced && !list_containers)
4487 needed->obj->traced = true;
4488 path = needed->obj->path;
4492 name = (char *)obj->strtab + needed->name;
4493 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4495 fmt = is_lib ? fmt1 : fmt2;
4496 while ((c = *fmt++) != '\0') {
4522 rtld_putstr(main_local);
4525 rtld_putstr(obj_main->path);
4532 rtld_printf("%d", sodp->sod_major);
4535 rtld_printf("%d", sodp->sod_minor);
4542 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4555 * Unload a dlopened object and its dependencies from memory and from
4556 * our data structures. It is assumed that the DAG rooted in the
4557 * object has already been unreferenced, and that the object has a
4558 * reference count of 0.
4561 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4563 Obj_Entry marker, *obj, *next;
4565 assert(root->refcount == 0);
4568 * Pass over the DAG removing unreferenced objects from
4569 * appropriate lists.
4571 unlink_object(root);
4573 /* Unmap all objects that are no longer referenced. */
4574 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4575 next = TAILQ_NEXT(obj, next);
4576 if (obj->marker || obj->refcount != 0)
4578 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4579 obj->mapsize, 0, obj->path);
4580 dbg("unloading \"%s\"", obj->path);
4582 * Unlink the object now to prevent new references from
4583 * being acquired while the bind lock is dropped in
4584 * recursive dlclose() invocations.
4586 TAILQ_REMOVE(&obj_list, obj, next);
4589 if (obj->filtees_loaded) {
4591 init_marker(&marker);
4592 TAILQ_INSERT_BEFORE(next, &marker, next);
4593 unload_filtees(obj, lockstate);
4594 next = TAILQ_NEXT(&marker, next);
4595 TAILQ_REMOVE(&obj_list, &marker, next);
4597 unload_filtees(obj, lockstate);
4599 release_object(obj);
4604 unlink_object(Obj_Entry *root)
4608 if (root->refcount == 0) {
4609 /* Remove the object from the RTLD_GLOBAL list. */
4610 objlist_remove(&list_global, root);
4612 /* Remove the object from all objects' DAG lists. */
4613 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4614 objlist_remove(&elm->obj->dldags, root);
4615 if (elm->obj != root)
4616 unlink_object(elm->obj);
4622 ref_dag(Obj_Entry *root)
4626 assert(root->dag_inited);
4627 STAILQ_FOREACH(elm, &root->dagmembers, link)
4628 elm->obj->refcount++;
4632 unref_dag(Obj_Entry *root)
4636 assert(root->dag_inited);
4637 STAILQ_FOREACH(elm, &root->dagmembers, link)
4638 elm->obj->refcount--;
4642 * Common code for MD __tls_get_addr().
4644 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4646 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4648 Elf_Addr *newdtv, *dtv;
4649 RtldLockState lockstate;
4653 /* Check dtv generation in case new modules have arrived */
4654 if (dtv[0] != tls_dtv_generation) {
4655 wlock_acquire(rtld_bind_lock, &lockstate);
4656 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4658 if (to_copy > tls_max_index)
4659 to_copy = tls_max_index;
4660 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4661 newdtv[0] = tls_dtv_generation;
4662 newdtv[1] = tls_max_index;
4664 lock_release(rtld_bind_lock, &lockstate);
4665 dtv = *dtvp = newdtv;
4668 /* Dynamically allocate module TLS if necessary */
4669 if (dtv[index + 1] == 0) {
4670 /* Signal safe, wlock will block out signals. */
4671 wlock_acquire(rtld_bind_lock, &lockstate);
4672 if (!dtv[index + 1])
4673 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4674 lock_release(rtld_bind_lock, &lockstate);
4676 return ((void *)(dtv[index + 1] + offset));
4680 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4685 /* Check dtv generation in case new modules have arrived */
4686 if (__predict_true(dtv[0] == tls_dtv_generation &&
4687 dtv[index + 1] != 0))
4688 return ((void *)(dtv[index + 1] + offset));
4689 return (tls_get_addr_slow(dtvp, index, offset));
4692 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4693 defined(__powerpc__) || defined(__riscv)
4696 * Return pointer to allocated TLS block
4699 get_tls_block_ptr(void *tcb, size_t tcbsize)
4701 size_t extra_size, post_size, pre_size, tls_block_size;
4702 size_t tls_init_align;
4704 tls_init_align = MAX(obj_main->tlsalign, 1);
4706 /* Compute fragments sizes. */
4707 extra_size = tcbsize - TLS_TCB_SIZE;
4708 post_size = calculate_tls_post_size(tls_init_align);
4709 tls_block_size = tcbsize + post_size;
4710 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4712 return ((char *)tcb - pre_size - extra_size);
4716 * Allocate Static TLS using the Variant I method.
4718 * For details on the layout, see lib/libc/gen/tls.c.
4720 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4721 * it is based on tls_last_offset, and TLS offsets here are really TCB
4722 * offsets, whereas libc's tls_static_space is just the executable's static
4726 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4730 Elf_Addr *dtv, **tcb;
4733 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4734 size_t tls_init_align;
4736 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4739 assert(tcbsize >= TLS_TCB_SIZE);
4740 maxalign = MAX(tcbalign, tls_static_max_align);
4741 tls_init_align = MAX(obj_main->tlsalign, 1);
4743 /* Compute fragmets sizes. */
4744 extra_size = tcbsize - TLS_TCB_SIZE;
4745 post_size = calculate_tls_post_size(tls_init_align);
4746 tls_block_size = tcbsize + post_size;
4747 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4748 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4750 /* Allocate whole TLS block */
4751 tls_block = malloc_aligned(tls_block_size, maxalign);
4752 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4754 if (oldtcb != NULL) {
4755 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4757 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4759 /* Adjust the DTV. */
4761 for (i = 0; i < dtv[1]; i++) {
4762 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4763 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4764 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4768 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4770 dtv[0] = tls_dtv_generation;
4771 dtv[1] = tls_max_index;
4773 for (obj = globallist_curr(objs); obj != NULL;
4774 obj = globallist_next(obj)) {
4775 if (obj->tlsoffset > 0) {
4776 addr = (Elf_Addr)tcb + obj->tlsoffset;
4777 if (obj->tlsinitsize > 0)
4778 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4779 if (obj->tlssize > obj->tlsinitsize)
4780 memset((void*) (addr + obj->tlsinitsize), 0,
4781 obj->tlssize - obj->tlsinitsize);
4782 dtv[obj->tlsindex + 1] = addr;
4791 free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
4794 Elf_Addr tlsstart, tlsend;
4796 size_t dtvsize, i, tls_init_align;
4798 assert(tcbsize >= TLS_TCB_SIZE);
4799 tls_init_align = MAX(obj_main->tlsalign, 1);
4801 /* Compute fragments sizes. */
4802 post_size = calculate_tls_post_size(tls_init_align);
4804 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
4805 tlsend = (Elf_Addr)tcb + tls_static_space;
4807 dtv = *(Elf_Addr **)tcb;
4809 for (i = 0; i < dtvsize; i++) {
4810 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4811 free((void*)dtv[i+2]);
4815 free_aligned(get_tls_block_ptr(tcb, tcbsize));
4820 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4823 * Allocate Static TLS using the Variant II method.
4826 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4829 size_t size, ralign;
4831 Elf_Addr *dtv, *olddtv;
4832 Elf_Addr segbase, oldsegbase, addr;
4836 if (tls_static_max_align > ralign)
4837 ralign = tls_static_max_align;
4838 size = round(tls_static_space, ralign) + round(tcbsize, ralign);
4840 assert(tcbsize >= 2*sizeof(Elf_Addr));
4841 tls = malloc_aligned(size, ralign);
4842 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4844 segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
4845 ((Elf_Addr*)segbase)[0] = segbase;
4846 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4848 dtv[0] = tls_dtv_generation;
4849 dtv[1] = tls_max_index;
4853 * Copy the static TLS block over whole.
4855 oldsegbase = (Elf_Addr) oldtls;
4856 memcpy((void *)(segbase - tls_static_space),
4857 (const void *)(oldsegbase - tls_static_space),
4861 * If any dynamic TLS blocks have been created tls_get_addr(),
4864 olddtv = ((Elf_Addr**)oldsegbase)[1];
4865 for (i = 0; i < olddtv[1]; i++) {
4866 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4867 dtv[i+2] = olddtv[i+2];
4873 * We assume that this block was the one we created with
4874 * allocate_initial_tls().
4876 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4878 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4879 if (obj->marker || obj->tlsoffset == 0)
4881 addr = segbase - obj->tlsoffset;
4882 memset((void*) (addr + obj->tlsinitsize),
4883 0, obj->tlssize - obj->tlsinitsize);
4885 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4886 dtv[obj->tlsindex + 1] = addr;
4890 return (void*) segbase;
4894 free_tls(void *tls, size_t tcbsize, size_t tcbalign)
4897 size_t size, ralign;
4899 Elf_Addr tlsstart, tlsend;
4902 * Figure out the size of the initial TLS block so that we can
4903 * find stuff which ___tls_get_addr() allocated dynamically.
4906 if (tls_static_max_align > ralign)
4907 ralign = tls_static_max_align;
4908 size = round(tls_static_space, ralign);
4910 dtv = ((Elf_Addr**)tls)[1];
4912 tlsend = (Elf_Addr) tls;
4913 tlsstart = tlsend - size;
4914 for (i = 0; i < dtvsize; i++) {
4915 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
4916 free_aligned((void *)dtv[i + 2]);
4920 free_aligned((void *)tlsstart);
4927 * Allocate TLS block for module with given index.
4930 allocate_module_tls(int index)
4935 TAILQ_FOREACH(obj, &obj_list, next) {
4938 if (obj->tlsindex == index)
4942 _rtld_error("Can't find module with TLS index %d", index);
4946 p = malloc_aligned(obj->tlssize, obj->tlsalign);
4947 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4948 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4954 allocate_tls_offset(Obj_Entry *obj)
4961 if (obj->tlssize == 0) {
4962 obj->tls_done = true;
4966 if (tls_last_offset == 0)
4967 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4969 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4970 obj->tlssize, obj->tlsalign);
4973 * If we have already fixed the size of the static TLS block, we
4974 * must stay within that size. When allocating the static TLS, we
4975 * leave a small amount of space spare to be used for dynamically
4976 * loading modules which use static TLS.
4978 if (tls_static_space != 0) {
4979 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4981 } else if (obj->tlsalign > tls_static_max_align) {
4982 tls_static_max_align = obj->tlsalign;
4985 tls_last_offset = obj->tlsoffset = off;
4986 tls_last_size = obj->tlssize;
4987 obj->tls_done = true;
4993 free_tls_offset(Obj_Entry *obj)
4997 * If we were the last thing to allocate out of the static TLS
4998 * block, we give our space back to the 'allocator'. This is a
4999 * simplistic workaround to allow libGL.so.1 to be loaded and
5000 * unloaded multiple times.
5002 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5003 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5004 tls_last_offset -= obj->tlssize;
5010 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5013 RtldLockState lockstate;
5015 wlock_acquire(rtld_bind_lock, &lockstate);
5016 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5018 lock_release(rtld_bind_lock, &lockstate);
5023 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5025 RtldLockState lockstate;
5027 wlock_acquire(rtld_bind_lock, &lockstate);
5028 free_tls(tcb, tcbsize, tcbalign);
5029 lock_release(rtld_bind_lock, &lockstate);
5033 object_add_name(Obj_Entry *obj, const char *name)
5039 entry = malloc(sizeof(Name_Entry) + len);
5041 if (entry != NULL) {
5042 strcpy(entry->name, name);
5043 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5048 object_match_name(const Obj_Entry *obj, const char *name)
5052 STAILQ_FOREACH(entry, &obj->names, link) {
5053 if (strcmp(name, entry->name) == 0)
5060 locate_dependency(const Obj_Entry *obj, const char *name)
5062 const Objlist_Entry *entry;
5063 const Needed_Entry *needed;
5065 STAILQ_FOREACH(entry, &list_main, link) {
5066 if (object_match_name(entry->obj, name))
5070 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5071 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5072 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5074 * If there is DT_NEEDED for the name we are looking for,
5075 * we are all set. Note that object might not be found if
5076 * dependency was not loaded yet, so the function can
5077 * return NULL here. This is expected and handled
5078 * properly by the caller.
5080 return (needed->obj);
5083 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5089 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5090 const Elf_Vernaux *vna)
5092 const Elf_Verdef *vd;
5093 const char *vername;
5095 vername = refobj->strtab + vna->vna_name;
5096 vd = depobj->verdef;
5098 _rtld_error("%s: version %s required by %s not defined",
5099 depobj->path, vername, refobj->path);
5103 if (vd->vd_version != VER_DEF_CURRENT) {
5104 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5105 depobj->path, vd->vd_version);
5108 if (vna->vna_hash == vd->vd_hash) {
5109 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5110 ((char *)vd + vd->vd_aux);
5111 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5114 if (vd->vd_next == 0)
5116 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5118 if (vna->vna_flags & VER_FLG_WEAK)
5120 _rtld_error("%s: version %s required by %s not found",
5121 depobj->path, vername, refobj->path);
5126 rtld_verify_object_versions(Obj_Entry *obj)
5128 const Elf_Verneed *vn;
5129 const Elf_Verdef *vd;
5130 const Elf_Verdaux *vda;
5131 const Elf_Vernaux *vna;
5132 const Obj_Entry *depobj;
5133 int maxvernum, vernum;
5135 if (obj->ver_checked)
5137 obj->ver_checked = true;
5141 * Walk over defined and required version records and figure out
5142 * max index used by any of them. Do very basic sanity checking
5146 while (vn != NULL) {
5147 if (vn->vn_version != VER_NEED_CURRENT) {
5148 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5149 obj->path, vn->vn_version);
5152 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
5154 vernum = VER_NEED_IDX(vna->vna_other);
5155 if (vernum > maxvernum)
5157 if (vna->vna_next == 0)
5159 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
5161 if (vn->vn_next == 0)
5163 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
5167 while (vd != NULL) {
5168 if (vd->vd_version != VER_DEF_CURRENT) {
5169 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5170 obj->path, vd->vd_version);
5173 vernum = VER_DEF_IDX(vd->vd_ndx);
5174 if (vernum > maxvernum)
5176 if (vd->vd_next == 0)
5178 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5185 * Store version information in array indexable by version index.
5186 * Verify that object version requirements are satisfied along the
5189 obj->vernum = maxvernum + 1;
5190 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5193 while (vd != NULL) {
5194 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5195 vernum = VER_DEF_IDX(vd->vd_ndx);
5196 assert(vernum <= maxvernum);
5197 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
5198 obj->vertab[vernum].hash = vd->vd_hash;
5199 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5200 obj->vertab[vernum].file = NULL;
5201 obj->vertab[vernum].flags = 0;
5203 if (vd->vd_next == 0)
5205 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
5209 while (vn != NULL) {
5210 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5213 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
5215 if (check_object_provided_version(obj, depobj, vna))
5217 vernum = VER_NEED_IDX(vna->vna_other);
5218 assert(vernum <= maxvernum);
5219 obj->vertab[vernum].hash = vna->vna_hash;
5220 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5221 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5222 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5223 VER_INFO_HIDDEN : 0;
5224 if (vna->vna_next == 0)
5226 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
5228 if (vn->vn_next == 0)
5230 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
5236 rtld_verify_versions(const Objlist *objlist)
5238 Objlist_Entry *entry;
5242 STAILQ_FOREACH(entry, objlist, link) {
5244 * Skip dummy objects or objects that have their version requirements
5247 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5249 if (rtld_verify_object_versions(entry->obj) == -1) {
5251 if (ld_tracing == NULL)
5255 if (rc == 0 || ld_tracing != NULL)
5256 rc = rtld_verify_object_versions(&obj_rtld);
5261 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5266 vernum = VER_NDX(obj->versyms[symnum]);
5267 if (vernum >= obj->vernum) {
5268 _rtld_error("%s: symbol %s has wrong verneed value %d",
5269 obj->path, obj->strtab + symnum, vernum);
5270 } else if (obj->vertab[vernum].hash != 0) {
5271 return &obj->vertab[vernum];
5278 _rtld_get_stack_prot(void)
5281 return (stack_prot);
5285 _rtld_is_dlopened(void *arg)
5288 RtldLockState lockstate;
5291 rlock_acquire(rtld_bind_lock, &lockstate);
5294 obj = obj_from_addr(arg);
5296 _rtld_error("No shared object contains address");
5297 lock_release(rtld_bind_lock, &lockstate);
5300 res = obj->dlopened ? 1 : 0;
5301 lock_release(rtld_bind_lock, &lockstate);
5306 obj_enforce_relro(Obj_Entry *obj)
5309 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5311 _rtld_error("%s: Cannot enforce relro protection: %s",
5312 obj->path, rtld_strerror(errno));
5319 map_stacks_exec(RtldLockState *lockstate)
5321 void (*thr_map_stacks_exec)(void);
5323 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5325 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5326 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5327 if (thr_map_stacks_exec != NULL) {
5328 stack_prot |= PROT_EXEC;
5329 thr_map_stacks_exec();
5334 symlook_init(SymLook *dst, const char *name)
5337 bzero(dst, sizeof(*dst));
5339 dst->hash = elf_hash(name);
5340 dst->hash_gnu = gnu_hash(name);
5344 symlook_init_from_req(SymLook *dst, const SymLook *src)
5347 dst->name = src->name;
5348 dst->hash = src->hash;
5349 dst->hash_gnu = src->hash_gnu;
5350 dst->ventry = src->ventry;
5351 dst->flags = src->flags;
5352 dst->defobj_out = NULL;
5353 dst->sym_out = NULL;
5354 dst->lockstate = src->lockstate;
5358 open_binary_fd(const char *argv0, bool search_in_path)
5360 char *pathenv, *pe, binpath[PATH_MAX];
5363 if (search_in_path && strchr(argv0, '/') == NULL) {
5364 pathenv = getenv("PATH");
5365 if (pathenv == NULL) {
5366 _rtld_error("-p and no PATH environment variable");
5369 pathenv = strdup(pathenv);
5370 if (pathenv == NULL) {
5371 _rtld_error("Cannot allocate memory");
5376 while ((pe = strsep(&pathenv, ":")) != NULL) {
5377 if (strlcpy(binpath, pe, sizeof(binpath)) >=
5380 if (binpath[0] != '\0' &&
5381 strlcat(binpath, "/", sizeof(binpath)) >=
5384 if (strlcat(binpath, argv0, sizeof(binpath)) >=
5387 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5388 if (fd != -1 || errno != ENOENT)
5393 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5397 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5404 * Parse a set of command-line arguments.
5407 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp)
5410 int fd, i, j, arglen;
5413 dbg("Parsing command-line arguments");
5417 for (i = 1; i < argc; i++ ) {
5419 dbg("argv[%d]: '%s'", i, arg);
5422 * rtld arguments end with an explicit "--" or with the first
5423 * non-prefixed argument.
5425 if (strcmp(arg, "--") == 0) {
5433 * All other arguments are single-character options that can
5434 * be combined, so we need to search through `arg` for them.
5436 arglen = strlen(arg);
5437 for (j = 1; j < arglen; j++) {
5440 print_usage(argv[0]);
5442 } else if (opt == 'f') {
5444 * -f XX can be used to specify a descriptor for the
5445 * binary named at the command line (i.e., the later
5446 * argument will specify the process name but the
5447 * descriptor is what will actually be executed)
5449 if (j != arglen - 1) {
5450 /* -f must be the last option in, e.g., -abcf */
5451 _rtld_error("Invalid options: %s", arg);
5455 fd = parse_integer(argv[i]);
5457 _rtld_error("Invalid file descriptor: '%s'",
5463 } else if (opt == 'p') {
5466 _rtld_error("Invalid argument: '%s'", arg);
5467 print_usage(argv[0]);
5477 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5480 parse_integer(const char *str)
5482 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5489 for (c = *str; c != '\0'; c = *++str) {
5490 if (c < '0' || c > '9')
5497 /* Make sure we actually parsed something. */
5504 print_usage(const char *argv0)
5507 rtld_printf("Usage: %s [-h] [-f <FD>] [--] <binary> [<args>]\n"
5510 " -h Display this help message\n"
5511 " -p Search in PATH for named binary\n"
5512 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5513 " -- End of RTLD options\n"
5514 " <binary> Name of process to execute\n"
5515 " <args> Arguments to the executed process\n", argv0);
5519 * Overrides for libc_pic-provided functions.
5523 __getosreldate(void)
5533 oid[1] = KERN_OSRELDATE;
5535 len = sizeof(osrel);
5536 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5537 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5549 void (*__cleanup)(void);
5550 int __isthreaded = 0;
5551 int _thread_autoinit_dummy_decl = 1;
5554 * No unresolved symbols for rtld.
5557 __pthread_cxa_finalize(struct dl_phdr_info *a)
5562 rtld_strerror(int errnum)
5565 if (errnum < 0 || errnum >= sys_nerr)
5566 return ("Unknown error");
5567 return (sys_errlist[errnum]);