2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
6 * Copyright 2009-2013 Konstantin Belousov <kib@FreeBSD.ORG>.
7 * Copyright 2012 John Marino <draco@marino.st>.
8 * Copyright 2014-2017 The FreeBSD Foundation
11 * Portions of this software were developed by Konstantin Belousov
12 * under sponsorship from the FreeBSD Foundation.
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 * Dynamic linker for ELF.
38 * John Polstra <jdp@polstra.com>.
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
44 #include <sys/param.h>
45 #include <sys/mount.h>
48 #include <sys/sysctl.h>
50 #include <sys/utsname.h>
51 #include <sys/ktrace.h>
68 #include "rtld_printf.h"
69 #include "rtld_malloc.h"
70 #include "rtld_utrace.h"
74 typedef void (*func_ptr_type)(void);
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 /* Variables that cannot be static: */
79 extern struct r_debug r_debug; /* For GDB */
80 extern int _thread_autoinit_dummy_decl;
81 extern char* __progname;
82 extern void (*__cleanup)(void);
86 * Function declarations.
88 static const char *basename(const char *);
89 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
90 const Elf_Dyn **, const Elf_Dyn **);
91 static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
93 static bool digest_dynamic(Obj_Entry *, int);
94 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
95 static void distribute_static_tls(Objlist *, RtldLockState *);
96 static Obj_Entry *dlcheck(void *);
97 static int dlclose_locked(void *, RtldLockState *);
98 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
99 int lo_flags, int mode, RtldLockState *lockstate);
100 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
101 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
102 static bool donelist_check(DoneList *, const Obj_Entry *);
103 static void errmsg_restore(char *);
104 static char *errmsg_save(void);
105 static void *fill_search_info(const char *, size_t, void *);
106 static char *find_library(const char *, const Obj_Entry *, int *);
107 static const char *gethints(bool);
108 static void hold_object(Obj_Entry *);
109 static void unhold_object(Obj_Entry *);
110 static void init_dag(Obj_Entry *);
111 static void init_marker(Obj_Entry *);
112 static void init_pagesizes(Elf_Auxinfo **aux_info);
113 static void init_rtld(caddr_t, Elf_Auxinfo **);
114 static void initlist_add_neededs(Needed_Entry *, Objlist *);
115 static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *);
116 static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *);
117 static void linkmap_add(Obj_Entry *);
118 static void linkmap_delete(Obj_Entry *);
119 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
120 static void unload_filtees(Obj_Entry *, RtldLockState *);
121 static int load_needed_objects(Obj_Entry *, int);
122 static int load_preload_objects(void);
123 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
124 static void map_stacks_exec(RtldLockState *);
125 static int obj_disable_relro(Obj_Entry *);
126 static int obj_enforce_relro(Obj_Entry *);
127 static Obj_Entry *obj_from_addr(const void *);
128 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
129 static void objlist_call_init(Objlist *, RtldLockState *);
130 static void objlist_clear(Objlist *);
131 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
132 static void objlist_init(Objlist *);
133 static void objlist_push_head(Objlist *, Obj_Entry *);
134 static void objlist_push_tail(Objlist *, Obj_Entry *);
135 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
136 static void objlist_remove(Objlist *, Obj_Entry *);
137 static int open_binary_fd(const char *argv0, bool search_in_path,
138 const char **binpath_res);
139 static int parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
141 static int parse_integer(const char *);
142 static void *path_enumerate(const char *, path_enum_proc, const char *, void *);
143 static void print_usage(const char *argv0);
144 static void release_object(Obj_Entry *);
145 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
146 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
147 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
148 int flags, RtldLockState *lockstate);
149 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
151 static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *);
152 static int rtld_dirname(const char *, char *);
153 static int rtld_dirname_abs(const char *, char *);
154 static void *rtld_dlopen(const char *name, int fd, int mode);
155 static void rtld_exit(void);
156 static void rtld_nop_exit(void);
157 static char *search_library_path(const char *, const char *, const char *,
159 static char *search_library_pathfds(const char *, const char *, int *);
160 static const void **get_program_var_addr(const char *, RtldLockState *);
161 static void set_program_var(const char *, const void *);
162 static int symlook_default(SymLook *, const Obj_Entry *refobj);
163 static int symlook_global(SymLook *, DoneList *);
164 static void symlook_init_from_req(SymLook *, const SymLook *);
165 static int symlook_list(SymLook *, const Objlist *, DoneList *);
166 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
167 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
168 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
169 static void trace_loaded_objects(Obj_Entry *);
170 static void unlink_object(Obj_Entry *);
171 static void unload_object(Obj_Entry *, RtldLockState *lockstate);
172 static void unref_dag(Obj_Entry *);
173 static void ref_dag(Obj_Entry *);
174 static char *origin_subst_one(Obj_Entry *, char *, const char *,
176 static char *origin_subst(Obj_Entry *, const char *);
177 static bool obj_resolve_origin(Obj_Entry *obj);
178 static void preinit_main(void);
179 static int rtld_verify_versions(const Objlist *);
180 static int rtld_verify_object_versions(Obj_Entry *);
181 static void object_add_name(Obj_Entry *, const char *);
182 static int object_match_name(const Obj_Entry *, const char *);
183 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
184 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
185 struct dl_phdr_info *phdr_info);
186 static uint32_t gnu_hash(const char *);
187 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
188 const unsigned long);
190 void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported;
191 void _r_debug_postinit(struct link_map *) __noinline __exported;
193 int __sys_openat(int, const char *, int, ...);
198 static char *error_message; /* Message for dlerror(), or NULL */
199 struct r_debug r_debug __exported; /* for GDB; */
200 static bool libmap_disable; /* Disable libmap */
201 static bool ld_loadfltr; /* Immediate filters processing */
202 static char *libmap_override; /* Maps to use in addition to libmap.conf */
203 static bool trust; /* False for setuid and setgid programs */
204 static bool dangerous_ld_env; /* True if environment variables have been
205 used to affect the libraries loaded */
206 bool ld_bind_not; /* Disable PLT update */
207 static char *ld_bind_now; /* Environment variable for immediate binding */
208 static char *ld_debug; /* Environment variable for debugging */
209 static char *ld_library_path; /* Environment variable for search path */
210 static char *ld_library_dirs; /* Environment variable for library descriptors */
211 static char *ld_preload; /* Environment variable for libraries to
213 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
214 static const char *ld_tracing; /* Called from ldd to print libs */
215 static char *ld_utrace; /* Use utrace() to log events. */
216 static struct obj_entry_q obj_list; /* Queue of all loaded objects */
217 static Obj_Entry *obj_main; /* The main program shared object */
218 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
219 static unsigned int obj_count; /* Number of objects in obj_list */
220 static unsigned int obj_loads; /* Number of loads of objects (gen count) */
222 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
223 STAILQ_HEAD_INITIALIZER(list_global);
224 static Objlist list_main = /* Objects loaded at program startup */
225 STAILQ_HEAD_INITIALIZER(list_main);
226 static Objlist list_fini = /* Objects needing fini() calls */
227 STAILQ_HEAD_INITIALIZER(list_fini);
229 Elf_Sym sym_zero; /* For resolving undefined weak refs. */
231 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
233 extern Elf_Dyn _DYNAMIC;
234 #pragma weak _DYNAMIC
236 int dlclose(void *) __exported;
237 char *dlerror(void) __exported;
238 void *dlopen(const char *, int) __exported;
239 void *fdlopen(int, int) __exported;
240 void *dlsym(void *, const char *) __exported;
241 dlfunc_t dlfunc(void *, const char *) __exported;
242 void *dlvsym(void *, const char *, const char *) __exported;
243 int dladdr(const void *, Dl_info *) __exported;
244 void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *),
245 void (*)(void *), void (*)(void *), void (*)(void *)) __exported;
246 int dlinfo(void *, int , void *) __exported;
247 int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported;
248 int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported;
249 int _rtld_get_stack_prot(void) __exported;
250 int _rtld_is_dlopened(void *) __exported;
251 void _rtld_error(const char *, ...) __exported;
253 /* Only here to fix -Wmissing-prototypes warnings */
254 int __getosreldate(void);
255 void __pthread_cxa_finalize(struct dl_phdr_info *a);
256 func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp);
257 Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff);
261 static int osreldate;
264 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
265 static int max_stack_flags;
268 * Global declarations normally provided by crt1. The dynamic linker is
269 * not built with crt1, so we have to provide them ourselves.
275 * Used to pass argc, argv to init functions.
281 * Globals to control TLS allocation.
283 size_t tls_last_offset; /* Static TLS offset of last module */
284 size_t tls_last_size; /* Static TLS size of last module */
285 size_t tls_static_space; /* Static TLS space allocated */
286 static size_t tls_static_max_align;
287 Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */
288 int tls_max_index = 1; /* Largest module index allocated */
290 static bool ld_library_path_rpath = false;
293 * Globals for path names, and such
295 const char *ld_elf_hints_default = _PATH_ELF_HINTS;
296 const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF;
297 const char *ld_path_rtld = _PATH_RTLD;
298 const char *ld_standard_library_path = STANDARD_LIBRARY_PATH;
299 const char *ld_env_prefix = LD_;
301 static void (*rtld_exit_ptr)(void);
304 * Fill in a DoneList with an allocation large enough to hold all of
305 * the currently-loaded objects. Keep this as a macro since it calls
306 * alloca and we want that to occur within the scope of the caller.
308 #define donelist_init(dlp) \
309 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
310 assert((dlp)->objs != NULL), \
311 (dlp)->num_alloc = obj_count, \
314 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
315 if (ld_utrace != NULL) \
316 ld_utrace_log(e, h, mb, ms, r, n); \
320 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
321 int refcnt, const char *name)
323 struct utrace_rtld ut;
324 static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
326 memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
329 ut.mapbase = mapbase;
330 ut.mapsize = mapsize;
332 bzero(ut.name, sizeof(ut.name));
334 strlcpy(ut.name, name, sizeof(ut.name));
335 utrace(&ut, sizeof(ut));
338 #ifdef RTLD_VARIANT_ENV_NAMES
340 * construct the env variable based on the type of binary that's
343 static inline const char *
346 static char buffer[128];
348 strlcpy(buffer, ld_env_prefix, sizeof(buffer));
349 strlcat(buffer, var, sizeof(buffer));
357 * Main entry point for dynamic linking. The first argument is the
358 * stack pointer. The stack is expected to be laid out as described
359 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
360 * Specifically, the stack pointer points to a word containing
361 * ARGC. Following that in the stack is a null-terminated sequence
362 * of pointers to argument strings. Then comes a null-terminated
363 * sequence of pointers to environment strings. Finally, there is a
364 * sequence of "auxiliary vector" entries.
366 * The second argument points to a place to store the dynamic linker's
367 * exit procedure pointer and the third to a place to store the main
370 * The return value is the main program's entry point.
373 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
375 Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT];
376 Objlist_Entry *entry;
377 Obj_Entry *last_interposer, *obj, *preload_tail;
378 const Elf_Phdr *phdr;
380 RtldLockState lockstate;
383 char **argv, **env, **envp, *kexecpath, *library_path_rpath;
384 const char *argv0, *binpath;
386 char buf[MAXPATHLEN];
387 int argc, fd, i, phnum, rtld_argc;
388 bool dir_enable, explicit_fd, search_in_path;
391 * On entry, the dynamic linker itself has not been relocated yet.
392 * Be very careful not to reference any global data until after
393 * init_rtld has returned. It is OK to reference file-scope statics
394 * and string constants, and to call static and global functions.
397 /* Find the auxiliary vector on the stack. */
401 sp += argc + 1; /* Skip over arguments and NULL terminator */
403 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
405 aux = (Elf_Auxinfo *) sp;
407 /* Digest the auxiliary vector. */
408 for (i = 0; i < AT_COUNT; i++)
410 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
411 if (auxp->a_type < AT_COUNT)
412 aux_info[auxp->a_type] = auxp;
415 /* Initialize and relocate ourselves. */
416 assert(aux_info[AT_BASE] != NULL);
417 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
419 __progname = obj_rtld.path;
420 argv0 = argv[0] != NULL ? argv[0] : "(null)";
425 trust = !issetugid();
427 md_abi_variant_hook(aux_info);
430 if (aux_info[AT_EXECFD] != NULL) {
431 fd = aux_info[AT_EXECFD]->a_un.a_val;
433 assert(aux_info[AT_PHDR] != NULL);
434 phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr;
435 if (phdr == obj_rtld.phdr) {
437 _rtld_error("Tainted process refusing to run binary %s",
441 dbg("opening main program in direct exec mode");
443 rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0);
444 explicit_fd = (fd != -1);
447 fd = open_binary_fd(argv0, search_in_path, &binpath);
448 if (fstat(fd, &st) == -1) {
449 _rtld_error("Failed to fstat FD %d (%s): %s", fd,
450 explicit_fd ? "user-provided descriptor" : argv0,
451 rtld_strerror(errno));
456 * Rough emulation of the permission checks done by
457 * execve(2), only Unix DACs are checked, ACLs are
458 * ignored. Preserve the semantic of disabling owner
459 * to execute if owner x bit is cleared, even if
460 * others x bit is enabled.
461 * mmap(2) does not allow to mmap with PROT_EXEC if
462 * binary' file comes from noexec mount. We cannot
463 * set a text reference on the binary.
466 if (st.st_uid == geteuid()) {
467 if ((st.st_mode & S_IXUSR) != 0)
469 } else if (st.st_gid == getegid()) {
470 if ((st.st_mode & S_IXGRP) != 0)
472 } else if ((st.st_mode & S_IXOTH) != 0) {
476 _rtld_error("No execute permission for binary %s",
482 * For direct exec mode, argv[0] is the interpreter
483 * name, we must remove it and shift arguments left
484 * before invoking binary main. Since stack layout
485 * places environment pointers and aux vectors right
486 * after the terminating NULL, we must shift
487 * environment and aux as well.
489 main_argc = argc - rtld_argc;
490 for (i = 0; i <= main_argc; i++)
491 argv[i] = argv[i + rtld_argc];
493 environ = env = envp = argv + main_argc + 1;
495 *envp = *(envp + rtld_argc);
497 } while (*envp != NULL);
498 aux = auxp = (Elf_Auxinfo *)envp;
499 auxpf = (Elf_Auxinfo *)(envp + rtld_argc);
500 /* XXXKIB insert place for AT_EXECPATH if not present */
501 for (;; auxp++, auxpf++) {
503 if (auxp->a_type == AT_NULL)
507 /* Point AT_EXECPATH auxv and aux_info to the binary path. */
508 if (binpath == NULL) {
509 aux_info[AT_EXECPATH] = NULL;
511 if (aux_info[AT_EXECPATH] == NULL) {
512 aux_info[AT_EXECPATH] = xmalloc(sizeof(Elf_Auxinfo));
513 aux_info[AT_EXECPATH]->a_type = AT_EXECPATH;
515 aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *,
519 _rtld_error("No binary");
525 ld_bind_now = getenv(_LD("BIND_NOW"));
528 * If the process is tainted, then we un-set the dangerous environment
529 * variables. The process will be marked as tainted until setuid(2)
530 * is called. If any child process calls setuid(2) we do not want any
531 * future processes to honor the potentially un-safe variables.
534 if (unsetenv(_LD("PRELOAD")) || unsetenv(_LD("LIBMAP")) ||
535 unsetenv(_LD("LIBRARY_PATH")) || unsetenv(_LD("LIBRARY_PATH_FDS")) ||
536 unsetenv(_LD("LIBMAP_DISABLE")) || unsetenv(_LD("BIND_NOT")) ||
537 unsetenv(_LD("DEBUG")) || unsetenv(_LD("ELF_HINTS_PATH")) ||
538 unsetenv(_LD("LOADFLTR")) || unsetenv(_LD("LIBRARY_PATH_RPATH"))) {
539 _rtld_error("environment corrupt; aborting");
543 ld_debug = getenv(_LD("DEBUG"));
544 if (ld_bind_now == NULL)
545 ld_bind_not = getenv(_LD("BIND_NOT")) != NULL;
546 libmap_disable = getenv(_LD("LIBMAP_DISABLE")) != NULL;
547 libmap_override = getenv(_LD("LIBMAP"));
548 ld_library_path = getenv(_LD("LIBRARY_PATH"));
549 ld_library_dirs = getenv(_LD("LIBRARY_PATH_FDS"));
550 ld_preload = getenv(_LD("PRELOAD"));
551 ld_elf_hints_path = getenv(_LD("ELF_HINTS_PATH"));
552 ld_loadfltr = getenv(_LD("LOADFLTR")) != NULL;
553 library_path_rpath = getenv(_LD("LIBRARY_PATH_RPATH"));
554 if (library_path_rpath != NULL) {
555 if (library_path_rpath[0] == 'y' ||
556 library_path_rpath[0] == 'Y' ||
557 library_path_rpath[0] == '1')
558 ld_library_path_rpath = true;
560 ld_library_path_rpath = false;
562 dangerous_ld_env = libmap_disable || (libmap_override != NULL) ||
563 (ld_library_path != NULL) || (ld_preload != NULL) ||
564 (ld_elf_hints_path != NULL) || ld_loadfltr;
565 ld_tracing = getenv(_LD("TRACE_LOADED_OBJECTS"));
566 ld_utrace = getenv(_LD("UTRACE"));
568 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
569 ld_elf_hints_path = ld_elf_hints_default;
571 if (ld_debug != NULL && *ld_debug != '\0')
573 dbg("%s is initialized, base address = %p", __progname,
574 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
575 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
576 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
578 dbg("initializing thread locks");
582 * Load the main program, or process its program header if it is
585 if (fd != -1) { /* Load the main program. */
586 dbg("loading main program");
587 obj_main = map_object(fd, argv0, NULL);
589 if (obj_main == NULL)
591 max_stack_flags = obj_main->stack_flags;
592 } else { /* Main program already loaded. */
593 dbg("processing main program's program header");
594 assert(aux_info[AT_PHDR] != NULL);
595 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
596 assert(aux_info[AT_PHNUM] != NULL);
597 phnum = aux_info[AT_PHNUM]->a_un.a_val;
598 assert(aux_info[AT_PHENT] != NULL);
599 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
600 assert(aux_info[AT_ENTRY] != NULL);
601 imgentry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
602 if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL)
606 if (aux_info[AT_EXECPATH] != NULL && fd == -1) {
607 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
608 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
609 if (kexecpath[0] == '/')
610 obj_main->path = kexecpath;
611 else if (getcwd(buf, sizeof(buf)) == NULL ||
612 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
613 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
614 obj_main->path = xstrdup(argv0);
616 obj_main->path = xstrdup(buf);
618 dbg("No AT_EXECPATH or direct exec");
619 obj_main->path = xstrdup(argv0);
621 dbg("obj_main path %s", obj_main->path);
622 obj_main->mainprog = true;
624 if (aux_info[AT_STACKPROT] != NULL &&
625 aux_info[AT_STACKPROT]->a_un.a_val != 0)
626 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
630 * Get the actual dynamic linker pathname from the executable if
631 * possible. (It should always be possible.) That ensures that
632 * gdb will find the right dynamic linker even if a non-standard
635 if (obj_main->interp != NULL &&
636 strcmp(obj_main->interp, obj_rtld.path) != 0) {
638 obj_rtld.path = xstrdup(obj_main->interp);
639 __progname = obj_rtld.path;
643 if (!digest_dynamic(obj_main, 0))
645 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
646 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
647 obj_main->dynsymcount);
649 linkmap_add(obj_main);
650 linkmap_add(&obj_rtld);
652 /* Link the main program into the list of objects. */
653 TAILQ_INSERT_HEAD(&obj_list, obj_main, next);
657 /* Initialize a fake symbol for resolving undefined weak references. */
658 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
659 sym_zero.st_shndx = SHN_UNDEF;
660 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
663 libmap_disable = (bool)lm_init(libmap_override);
665 dbg("loading LD_PRELOAD libraries");
666 if (load_preload_objects() == -1)
668 preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
670 dbg("loading needed objects");
671 if (load_needed_objects(obj_main, 0) == -1)
674 /* Make a list of all objects loaded at startup. */
675 last_interposer = obj_main;
676 TAILQ_FOREACH(obj, &obj_list, next) {
679 if (obj->z_interpose && obj != obj_main) {
680 objlist_put_after(&list_main, last_interposer, obj);
681 last_interposer = obj;
683 objlist_push_tail(&list_main, obj);
688 dbg("checking for required versions");
689 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
692 if (ld_tracing) { /* We're done */
693 trace_loaded_objects(obj_main);
697 if (getenv(_LD("DUMP_REL_PRE")) != NULL) {
698 dump_relocations(obj_main);
703 * Processing tls relocations requires having the tls offsets
704 * initialized. Prepare offsets before starting initial
705 * relocation processing.
707 dbg("initializing initial thread local storage offsets");
708 STAILQ_FOREACH(entry, &list_main, link) {
710 * Allocate all the initial objects out of the static TLS
711 * block even if they didn't ask for it.
713 allocate_tls_offset(entry->obj);
716 if (relocate_objects(obj_main,
717 ld_bind_now != NULL && *ld_bind_now != '\0',
718 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
721 dbg("doing copy relocations");
722 if (do_copy_relocations(obj_main) == -1)
725 if (getenv(_LD("DUMP_REL_POST")) != NULL) {
726 dump_relocations(obj_main);
733 * Setup TLS for main thread. This must be done after the
734 * relocations are processed, since tls initialization section
735 * might be the subject for relocations.
737 dbg("initializing initial thread local storage");
738 allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list)));
740 dbg("initializing key program variables");
741 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
742 set_program_var("environ", env);
743 set_program_var("__elf_aux_vector", aux);
745 /* Make a list of init functions to call. */
746 objlist_init(&initlist);
747 initlist_add_objects(globallist_curr(TAILQ_FIRST(&obj_list)),
748 preload_tail, &initlist);
750 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
752 map_stacks_exec(NULL);
754 if (!obj_main->crt_no_init) {
756 * Make sure we don't call the main program's init and fini
757 * functions for binaries linked with old crt1 which calls
760 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
761 obj_main->preinit_array = obj_main->init_array =
762 obj_main->fini_array = (Elf_Addr)NULL;
766 * Execute MD initializers required before we call the objects'
771 wlock_acquire(rtld_bind_lock, &lockstate);
773 dbg("resolving ifuncs");
774 if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL &&
775 *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1)
778 rtld_exit_ptr = rtld_exit;
779 if (obj_main->crt_no_init)
781 objlist_call_init(&initlist, &lockstate);
782 _r_debug_postinit(&obj_main->linkmap);
783 objlist_clear(&initlist);
784 dbg("loading filtees");
785 TAILQ_FOREACH(obj, &obj_list, next) {
788 if (ld_loadfltr || obj->z_loadfltr)
789 load_filtees(obj, 0, &lockstate);
792 dbg("enforcing main obj relro");
793 if (obj_enforce_relro(obj_main) == -1)
796 lock_release(rtld_bind_lock, &lockstate);
798 dbg("transferring control to program entry point = %p", obj_main->entry);
800 /* Return the exit procedure and the program entry point. */
801 *exit_proc = rtld_exit_ptr;
803 return (func_ptr_type) obj_main->entry;
807 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
812 ptr = (void *)make_function_pointer(def, obj);
813 target = call_ifunc_resolver(ptr);
814 return ((void *)target);
818 * NB: MIPS uses a private version of this function (_mips_rtld_bind).
819 * Changes to this function should be applied there as well.
822 _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
826 const Obj_Entry *defobj;
829 RtldLockState lockstate;
831 rlock_acquire(rtld_bind_lock, &lockstate);
832 if (sigsetjmp(lockstate.env, 0) != 0)
833 lock_upgrade(rtld_bind_lock, &lockstate);
835 rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff);
837 rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff);
839 where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
840 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT,
844 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
845 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
847 target = (Elf_Addr)(defobj->relocbase + def->st_value);
849 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
850 defobj->strtab + def->st_name, basename(obj->path),
851 (void *)target, basename(defobj->path));
854 * Write the new contents for the jmpslot. Note that depending on
855 * architecture, the value which we need to return back to the
856 * lazy binding trampoline may or may not be the target
857 * address. The value returned from reloc_jmpslot() is the value
858 * that the trampoline needs.
860 target = reloc_jmpslot(where, target, defobj, obj, rel);
861 lock_release(rtld_bind_lock, &lockstate);
866 * Error reporting function. Use it like printf. If formats the message
867 * into a buffer, and sets things up so that the next call to dlerror()
868 * will return the message.
871 _rtld_error(const char *fmt, ...)
873 static char buf[512];
877 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
880 LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, error_message);
884 * Return a dynamically-allocated copy of the current error message, if any.
889 return error_message == NULL ? NULL : xstrdup(error_message);
893 * Restore the current error message from a copy which was previously saved
894 * by errmsg_save(). The copy is freed.
897 errmsg_restore(char *saved_msg)
899 if (saved_msg == NULL)
900 error_message = NULL;
902 _rtld_error("%s", saved_msg);
908 basename(const char *name)
910 const char *p = strrchr(name, '/');
911 return p != NULL ? p + 1 : name;
914 static struct utsname uts;
917 origin_subst_one(Obj_Entry *obj, char *real, const char *kw,
918 const char *subst, bool may_free)
920 char *p, *p1, *res, *resp;
921 int subst_len, kw_len, subst_count, old_len, new_len;
926 * First, count the number of the keyword occurrences, to
927 * preallocate the final string.
929 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
936 * If the keyword is not found, just return.
938 * Return non-substituted string if resolution failed. We
939 * cannot do anything more reasonable, the failure mode of the
940 * caller is unresolved library anyway.
942 if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj)))
943 return (may_free ? real : xstrdup(real));
945 subst = obj->origin_path;
948 * There is indeed something to substitute. Calculate the
949 * length of the resulting string, and allocate it.
951 subst_len = strlen(subst);
952 old_len = strlen(real);
953 new_len = old_len + (subst_len - kw_len) * subst_count;
954 res = xmalloc(new_len + 1);
957 * Now, execute the substitution loop.
959 for (p = real, resp = res, *resp = '\0';;) {
962 /* Copy the prefix before keyword. */
963 memcpy(resp, p, p1 - p);
965 /* Keyword replacement. */
966 memcpy(resp, subst, subst_len);
974 /* Copy to the end of string and finish. */
982 origin_subst(Obj_Entry *obj, const char *real)
984 char *res1, *res2, *res3, *res4;
986 if (obj == NULL || !trust)
987 return (xstrdup(real));
988 if (uts.sysname[0] == '\0') {
989 if (uname(&uts) != 0) {
990 _rtld_error("utsname failed: %d", errno);
994 /* __DECONST is safe here since without may_free real is unchanged */
995 res1 = origin_subst_one(obj, __DECONST(char *, real), "$ORIGIN", NULL,
997 res2 = origin_subst_one(NULL, res1, "$OSNAME", uts.sysname, true);
998 res3 = origin_subst_one(NULL, res2, "$OSREL", uts.release, true);
999 res4 = origin_subst_one(NULL, res3, "$PLATFORM", uts.machine, true);
1006 const char *msg = dlerror();
1009 msg = "Fatal error";
1010 rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": ");
1011 rtld_fdputstr(STDERR_FILENO, msg);
1012 rtld_fdputchar(STDERR_FILENO, '\n');
1017 * Process a shared object's DYNAMIC section, and save the important
1018 * information in its Obj_Entry structure.
1021 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
1022 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
1024 const Elf_Dyn *dynp;
1025 Needed_Entry **needed_tail = &obj->needed;
1026 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
1027 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
1028 const Elf_Hashelt *hashtab;
1029 const Elf32_Word *hashval;
1030 Elf32_Word bkt, nmaskwords;
1032 int plttype = DT_REL;
1036 *dyn_runpath = NULL;
1038 obj->bind_now = false;
1039 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
1040 switch (dynp->d_tag) {
1043 obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr);
1047 obj->relsize = dynp->d_un.d_val;
1051 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
1055 obj->pltrel = (const Elf_Rel *)
1056 (obj->relocbase + dynp->d_un.d_ptr);
1060 obj->pltrelsize = dynp->d_un.d_val;
1064 obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr);
1068 obj->relasize = dynp->d_un.d_val;
1072 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1076 plttype = dynp->d_un.d_val;
1077 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1081 obj->symtab = (const Elf_Sym *)
1082 (obj->relocbase + dynp->d_un.d_ptr);
1086 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1090 obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr);
1094 obj->strsize = dynp->d_un.d_val;
1098 obj->verneed = (const Elf_Verneed *)(obj->relocbase +
1103 obj->verneednum = dynp->d_un.d_val;
1107 obj->verdef = (const Elf_Verdef *)(obj->relocbase +
1112 obj->verdefnum = dynp->d_un.d_val;
1116 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1122 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1124 obj->nbuckets = hashtab[0];
1125 obj->nchains = hashtab[1];
1126 obj->buckets = hashtab + 2;
1127 obj->chains = obj->buckets + obj->nbuckets;
1128 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1129 obj->buckets != NULL;
1135 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1137 obj->nbuckets_gnu = hashtab[0];
1138 obj->symndx_gnu = hashtab[1];
1139 nmaskwords = hashtab[2];
1140 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1141 obj->maskwords_bm_gnu = nmaskwords - 1;
1142 obj->shift2_gnu = hashtab[3];
1143 obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4);
1144 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1145 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1147 /* Number of bitmask words is required to be power of 2 */
1148 obj->valid_hash_gnu = powerof2(nmaskwords) &&
1149 obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL;
1155 Needed_Entry *nep = NEW(Needed_Entry);
1156 nep->name = dynp->d_un.d_val;
1161 needed_tail = &nep->next;
1167 Needed_Entry *nep = NEW(Needed_Entry);
1168 nep->name = dynp->d_un.d_val;
1172 *needed_filtees_tail = nep;
1173 needed_filtees_tail = &nep->next;
1175 if (obj->linkmap.l_refname == NULL)
1176 obj->linkmap.l_refname = (char *)dynp->d_un.d_val;
1182 Needed_Entry *nep = NEW(Needed_Entry);
1183 nep->name = dynp->d_un.d_val;
1187 *needed_aux_filtees_tail = nep;
1188 needed_aux_filtees_tail = &nep->next;
1193 obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr);
1197 obj->textrel = true;
1201 obj->symbolic = true;
1206 * We have to wait until later to process this, because we
1207 * might not have gotten the address of the string table yet.
1217 *dyn_runpath = dynp;
1221 obj->init = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1224 case DT_PREINIT_ARRAY:
1225 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1228 case DT_PREINIT_ARRAYSZ:
1229 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1233 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1236 case DT_INIT_ARRAYSZ:
1237 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1241 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1245 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1248 case DT_FINI_ARRAYSZ:
1249 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1253 * Don't process DT_DEBUG on MIPS as the dynamic section
1254 * is mapped read-only. DT_MIPS_RLD_MAP is used instead.
1260 dbg("Filling in DT_DEBUG entry");
1261 (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug;
1266 if (dynp->d_un.d_val & DF_ORIGIN)
1267 obj->z_origin = true;
1268 if (dynp->d_un.d_val & DF_SYMBOLIC)
1269 obj->symbolic = true;
1270 if (dynp->d_un.d_val & DF_TEXTREL)
1271 obj->textrel = true;
1272 if (dynp->d_un.d_val & DF_BIND_NOW)
1273 obj->bind_now = true;
1274 if (dynp->d_un.d_val & DF_STATIC_TLS)
1275 obj->static_tls = true;
1278 case DT_MIPS_LOCAL_GOTNO:
1279 obj->local_gotno = dynp->d_un.d_val;
1282 case DT_MIPS_SYMTABNO:
1283 obj->symtabno = dynp->d_un.d_val;
1286 case DT_MIPS_GOTSYM:
1287 obj->gotsym = dynp->d_un.d_val;
1290 case DT_MIPS_RLD_MAP:
1291 *((Elf_Addr *)(dynp->d_un.d_ptr)) = (Elf_Addr) &r_debug;
1294 case DT_MIPS_PLTGOT:
1295 obj->mips_pltgot = (Elf_Addr *)(obj->relocbase +
1301 #ifdef __powerpc64__
1302 case DT_PPC64_GLINK:
1303 obj->glink = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1308 if (dynp->d_un.d_val & DF_1_NOOPEN)
1309 obj->z_noopen = true;
1310 if (dynp->d_un.d_val & DF_1_ORIGIN)
1311 obj->z_origin = true;
1312 if (dynp->d_un.d_val & DF_1_GLOBAL)
1313 obj->z_global = true;
1314 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1315 obj->bind_now = true;
1316 if (dynp->d_un.d_val & DF_1_NODELETE)
1317 obj->z_nodelete = true;
1318 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1319 obj->z_loadfltr = true;
1320 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1321 obj->z_interpose = true;
1322 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1323 obj->z_nodeflib = true;
1324 if (dynp->d_un.d_val & DF_1_PIE)
1330 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1337 obj->traced = false;
1339 if (plttype == DT_RELA) {
1340 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1342 obj->pltrelasize = obj->pltrelsize;
1343 obj->pltrelsize = 0;
1346 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1347 if (obj->valid_hash_sysv)
1348 obj->dynsymcount = obj->nchains;
1349 else if (obj->valid_hash_gnu) {
1350 obj->dynsymcount = 0;
1351 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1352 if (obj->buckets_gnu[bkt] == 0)
1354 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1357 while ((*hashval++ & 1u) == 0);
1359 obj->dynsymcount += obj->symndx_gnu;
1362 if (obj->linkmap.l_refname != NULL)
1363 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj->
1368 obj_resolve_origin(Obj_Entry *obj)
1371 if (obj->origin_path != NULL)
1373 obj->origin_path = xmalloc(PATH_MAX);
1374 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1378 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1379 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1382 if (obj->z_origin && !obj_resolve_origin(obj))
1385 if (dyn_runpath != NULL) {
1386 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1387 obj->runpath = origin_subst(obj, obj->runpath);
1388 } else if (dyn_rpath != NULL) {
1389 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1390 obj->rpath = origin_subst(obj, obj->rpath);
1392 if (dyn_soname != NULL)
1393 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1398 digest_dynamic(Obj_Entry *obj, int early)
1400 const Elf_Dyn *dyn_rpath;
1401 const Elf_Dyn *dyn_soname;
1402 const Elf_Dyn *dyn_runpath;
1404 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1405 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1409 * Process a shared object's program header. This is used only for the
1410 * main program, when the kernel has already loaded the main program
1411 * into memory before calling the dynamic linker. It creates and
1412 * returns an Obj_Entry structure.
1415 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1418 const Elf_Phdr *phlimit = phdr + phnum;
1420 Elf_Addr note_start, note_end;
1424 for (ph = phdr; ph < phlimit; ph++) {
1425 if (ph->p_type != PT_PHDR)
1429 obj->phsize = ph->p_memsz;
1430 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1434 obj->stack_flags = PF_X | PF_R | PF_W;
1436 for (ph = phdr; ph < phlimit; ph++) {
1437 switch (ph->p_type) {
1440 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1444 if (nsegs == 0) { /* First load segment */
1445 obj->vaddrbase = trunc_page(ph->p_vaddr);
1446 obj->mapbase = obj->vaddrbase + obj->relocbase;
1447 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1449 } else { /* Last load segment */
1450 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1457 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1462 obj->tlssize = ph->p_memsz;
1463 obj->tlsalign = ph->p_align;
1464 obj->tlsinitsize = ph->p_filesz;
1465 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1466 obj->tlspoffset = ph->p_offset;
1470 obj->stack_flags = ph->p_flags;
1474 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1475 obj->relro_size = round_page(ph->p_memsz);
1479 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1480 note_end = note_start + ph->p_filesz;
1481 digest_notes(obj, note_start, note_end);
1486 _rtld_error("%s: too few PT_LOAD segments", path);
1495 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1497 const Elf_Note *note;
1498 const char *note_name;
1501 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1502 note = (const Elf_Note *)((const char *)(note + 1) +
1503 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1504 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1505 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1506 note->n_descsz != sizeof(int32_t))
1508 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1509 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1510 note->n_type != NT_FREEBSD_NOINIT_TAG)
1512 note_name = (const char *)(note + 1);
1513 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1514 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1516 switch (note->n_type) {
1517 case NT_FREEBSD_ABI_TAG:
1518 /* FreeBSD osrel note */
1519 p = (uintptr_t)(note + 1);
1520 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1521 obj->osrel = *(const int32_t *)(p);
1522 dbg("note osrel %d", obj->osrel);
1524 case NT_FREEBSD_FEATURE_CTL:
1525 /* FreeBSD ABI feature control note */
1526 p = (uintptr_t)(note + 1);
1527 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1528 obj->fctl0 = *(const uint32_t *)(p);
1529 dbg("note fctl0 %#x", obj->fctl0);
1531 case NT_FREEBSD_NOINIT_TAG:
1532 /* FreeBSD 'crt does not call init' note */
1533 obj->crt_no_init = true;
1534 dbg("note crt_no_init");
1541 dlcheck(void *handle)
1545 TAILQ_FOREACH(obj, &obj_list, next) {
1546 if (obj == (Obj_Entry *) handle)
1550 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1551 _rtld_error("Invalid shared object handle %p", handle);
1558 * If the given object is already in the donelist, return true. Otherwise
1559 * add the object to the list and return false.
1562 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1566 for (i = 0; i < dlp->num_used; i++)
1567 if (dlp->objs[i] == obj)
1570 * Our donelist allocation should always be sufficient. But if
1571 * our threads locking isn't working properly, more shared objects
1572 * could have been loaded since we allocated the list. That should
1573 * never happen, but we'll handle it properly just in case it does.
1575 if (dlp->num_used < dlp->num_alloc)
1576 dlp->objs[dlp->num_used++] = obj;
1581 * Hash function for symbol table lookup. Don't even think about changing
1582 * this. It is specified by the System V ABI.
1585 elf_hash(const char *name)
1587 const unsigned char *p = (const unsigned char *) name;
1588 unsigned long h = 0;
1591 while (*p != '\0') {
1592 h = (h << 4) + *p++;
1593 if ((g = h & 0xf0000000) != 0)
1601 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1602 * unsigned in case it's implemented with a wider type.
1605 gnu_hash(const char *s)
1611 for (c = *s; c != '\0'; c = *++s)
1613 return (h & 0xffffffff);
1618 * Find the library with the given name, and return its full pathname.
1619 * The returned string is dynamically allocated. Generates an error
1620 * message and returns NULL if the library cannot be found.
1622 * If the second argument is non-NULL, then it refers to an already-
1623 * loaded shared object, whose library search path will be searched.
1625 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1626 * descriptor (which is close-on-exec) will be passed out via the third
1629 * The search order is:
1630 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1631 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1633 * DT_RUNPATH in the referencing file
1634 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1636 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1638 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1641 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1643 char *pathname, *refobj_path;
1645 bool nodeflib, objgiven;
1647 objgiven = refobj != NULL;
1649 if (libmap_disable || !objgiven ||
1650 (name = lm_find(refobj->path, xname)) == NULL)
1653 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1654 if (name[0] != '/' && !trust) {
1655 _rtld_error("Absolute pathname required "
1656 "for shared object \"%s\"", name);
1659 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1660 __DECONST(char *, name)));
1663 dbg(" Searching for \"%s\"", name);
1664 refobj_path = objgiven ? refobj->path : NULL;
1667 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1668 * back to pre-conforming behaviour if user requested so with
1669 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1672 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1673 pathname = search_library_path(name, ld_library_path,
1675 if (pathname != NULL)
1677 if (refobj != NULL) {
1678 pathname = search_library_path(name, refobj->rpath,
1680 if (pathname != NULL)
1683 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1684 if (pathname != NULL)
1686 pathname = search_library_path(name, gethints(false),
1688 if (pathname != NULL)
1690 pathname = search_library_path(name, ld_standard_library_path,
1692 if (pathname != NULL)
1695 nodeflib = objgiven ? refobj->z_nodeflib : false;
1697 pathname = search_library_path(name, refobj->rpath,
1699 if (pathname != NULL)
1702 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1703 pathname = search_library_path(name, obj_main->rpath,
1705 if (pathname != NULL)
1708 pathname = search_library_path(name, ld_library_path,
1710 if (pathname != NULL)
1713 pathname = search_library_path(name, refobj->runpath,
1715 if (pathname != NULL)
1718 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1719 if (pathname != NULL)
1721 pathname = search_library_path(name, gethints(nodeflib),
1723 if (pathname != NULL)
1725 if (objgiven && !nodeflib) {
1726 pathname = search_library_path(name,
1727 ld_standard_library_path, refobj_path, fdp);
1728 if (pathname != NULL)
1733 if (objgiven && refobj->path != NULL) {
1734 _rtld_error("Shared object \"%s\" not found, "
1735 "required by \"%s\"", name, basename(refobj->path));
1737 _rtld_error("Shared object \"%s\" not found", name);
1743 * Given a symbol number in a referencing object, find the corresponding
1744 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1745 * no definition was found. Returns a pointer to the Obj_Entry of the
1746 * defining object via the reference parameter DEFOBJ_OUT.
1749 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1750 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1751 RtldLockState *lockstate)
1755 const Obj_Entry *defobj;
1756 const Ver_Entry *ve;
1762 * If we have already found this symbol, get the information from
1765 if (symnum >= refobj->dynsymcount)
1766 return NULL; /* Bad object */
1767 if (cache != NULL && cache[symnum].sym != NULL) {
1768 *defobj_out = cache[symnum].obj;
1769 return cache[symnum].sym;
1772 ref = refobj->symtab + symnum;
1773 name = refobj->strtab + ref->st_name;
1779 * We don't have to do a full scale lookup if the symbol is local.
1780 * We know it will bind to the instance in this load module; to
1781 * which we already have a pointer (ie ref). By not doing a lookup,
1782 * we not only improve performance, but it also avoids unresolvable
1783 * symbols when local symbols are not in the hash table. This has
1784 * been seen with the ia64 toolchain.
1786 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1787 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1788 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1791 symlook_init(&req, name);
1793 ve = req.ventry = fetch_ventry(refobj, symnum);
1794 req.lockstate = lockstate;
1795 res = symlook_default(&req, refobj);
1798 defobj = req.defobj_out;
1806 * If we found no definition and the reference is weak, treat the
1807 * symbol as having the value zero.
1809 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1815 *defobj_out = defobj;
1816 /* Record the information in the cache to avoid subsequent lookups. */
1817 if (cache != NULL) {
1818 cache[symnum].sym = def;
1819 cache[symnum].obj = defobj;
1822 if (refobj != &obj_rtld)
1823 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1824 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1830 * Return the search path from the ldconfig hints file, reading it if
1831 * necessary. If nostdlib is true, then the default search paths are
1832 * not added to result.
1834 * Returns NULL if there are problems with the hints file,
1835 * or if the search path there is empty.
1838 gethints(bool nostdlib)
1840 static char *filtered_path;
1841 static const char *hints;
1842 static struct elfhints_hdr hdr;
1843 struct fill_search_info_args sargs, hargs;
1844 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1845 struct dl_serpath *SLPpath, *hintpath;
1847 struct stat hint_stat;
1848 unsigned int SLPndx, hintndx, fndx, fcount;
1854 /* First call, read the hints file */
1855 if (hints == NULL) {
1856 /* Keep from trying again in case the hints file is bad. */
1859 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1863 * Check of hdr.dirlistlen value against type limit
1864 * intends to pacify static analyzers. Further
1865 * paranoia leads to checks that dirlist is fully
1866 * contained in the file range.
1868 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1869 hdr.magic != ELFHINTS_MAGIC ||
1870 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1871 fstat(fd, &hint_stat) == -1) {
1878 if (dl + hdr.dirlist < dl)
1881 if (dl + hdr.dirlistlen < dl)
1883 dl += hdr.dirlistlen;
1884 if (dl > hint_stat.st_size)
1886 p = xmalloc(hdr.dirlistlen + 1);
1887 if (pread(fd, p, hdr.dirlistlen + 1,
1888 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1889 p[hdr.dirlistlen] != '\0') {
1898 * If caller agreed to receive list which includes the default
1899 * paths, we are done. Otherwise, if we still did not
1900 * calculated filtered result, do it now.
1903 return (hints[0] != '\0' ? hints : NULL);
1904 if (filtered_path != NULL)
1908 * Obtain the list of all configured search paths, and the
1909 * list of the default paths.
1911 * First estimate the size of the results.
1913 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1915 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1918 sargs.request = RTLD_DI_SERINFOSIZE;
1919 sargs.serinfo = &smeta;
1920 hargs.request = RTLD_DI_SERINFOSIZE;
1921 hargs.serinfo = &hmeta;
1923 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1925 path_enumerate(hints, fill_search_info, NULL, &hargs);
1927 SLPinfo = xmalloc(smeta.dls_size);
1928 hintinfo = xmalloc(hmeta.dls_size);
1931 * Next fetch both sets of paths.
1933 sargs.request = RTLD_DI_SERINFO;
1934 sargs.serinfo = SLPinfo;
1935 sargs.serpath = &SLPinfo->dls_serpath[0];
1936 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1938 hargs.request = RTLD_DI_SERINFO;
1939 hargs.serinfo = hintinfo;
1940 hargs.serpath = &hintinfo->dls_serpath[0];
1941 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1943 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1945 path_enumerate(hints, fill_search_info, NULL, &hargs);
1948 * Now calculate the difference between two sets, by excluding
1949 * standard paths from the full set.
1953 filtered_path = xmalloc(hdr.dirlistlen + 1);
1954 hintpath = &hintinfo->dls_serpath[0];
1955 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1957 SLPpath = &SLPinfo->dls_serpath[0];
1959 * Check each standard path against current.
1961 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1962 /* matched, skip the path */
1963 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1971 * Not matched against any standard path, add the path
1972 * to result. Separate consequtive paths with ':'.
1975 filtered_path[fndx] = ':';
1979 flen = strlen(hintpath->dls_name);
1980 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1983 filtered_path[fndx] = '\0';
1989 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1993 init_dag(Obj_Entry *root)
1995 const Needed_Entry *needed;
1996 const Objlist_Entry *elm;
1999 if (root->dag_inited)
2001 donelist_init(&donelist);
2003 /* Root object belongs to own DAG. */
2004 objlist_push_tail(&root->dldags, root);
2005 objlist_push_tail(&root->dagmembers, root);
2006 donelist_check(&donelist, root);
2009 * Add dependencies of root object to DAG in breadth order
2010 * by exploiting the fact that each new object get added
2011 * to the tail of the dagmembers list.
2013 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2014 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
2015 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
2017 objlist_push_tail(&needed->obj->dldags, root);
2018 objlist_push_tail(&root->dagmembers, needed->obj);
2021 root->dag_inited = true;
2025 init_marker(Obj_Entry *marker)
2028 bzero(marker, sizeof(*marker));
2029 marker->marker = true;
2033 globallist_curr(const Obj_Entry *obj)
2040 return (__DECONST(Obj_Entry *, obj));
2041 obj = TAILQ_PREV(obj, obj_entry_q, next);
2046 globallist_next(const Obj_Entry *obj)
2050 obj = TAILQ_NEXT(obj, next);
2054 return (__DECONST(Obj_Entry *, obj));
2058 /* Prevent the object from being unmapped while the bind lock is dropped. */
2060 hold_object(Obj_Entry *obj)
2067 unhold_object(Obj_Entry *obj)
2070 assert(obj->holdcount > 0);
2071 if (--obj->holdcount == 0 && obj->unholdfree)
2072 release_object(obj);
2076 process_z(Obj_Entry *root)
2078 const Objlist_Entry *elm;
2082 * Walk over object DAG and process every dependent object
2083 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2084 * to grow their own DAG.
2086 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2087 * symlook_global() to work.
2089 * For DF_1_NODELETE, the DAG should have its reference upped.
2091 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2095 if (obj->z_nodelete && !obj->ref_nodel) {
2096 dbg("obj %s -z nodelete", obj->path);
2099 obj->ref_nodel = true;
2101 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2102 dbg("obj %s -z global", obj->path);
2103 objlist_push_tail(&list_global, obj);
2109 * Initialize the dynamic linker. The argument is the address at which
2110 * the dynamic linker has been mapped into memory. The primary task of
2111 * this function is to relocate the dynamic linker.
2114 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2116 Obj_Entry objtmp; /* Temporary rtld object */
2117 const Elf_Ehdr *ehdr;
2118 const Elf_Dyn *dyn_rpath;
2119 const Elf_Dyn *dyn_soname;
2120 const Elf_Dyn *dyn_runpath;
2122 #ifdef RTLD_INIT_PAGESIZES_EARLY
2123 /* The page size is required by the dynamic memory allocator. */
2124 init_pagesizes(aux_info);
2128 * Conjure up an Obj_Entry structure for the dynamic linker.
2130 * The "path" member can't be initialized yet because string constants
2131 * cannot yet be accessed. Below we will set it correctly.
2133 memset(&objtmp, 0, sizeof(objtmp));
2136 objtmp.mapbase = mapbase;
2138 objtmp.relocbase = mapbase;
2141 objtmp.dynamic = rtld_dynamic(&objtmp);
2142 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2143 assert(objtmp.needed == NULL);
2144 #if !defined(__mips__)
2145 /* MIPS has a bogus DT_TEXTREL. */
2146 assert(!objtmp.textrel);
2149 * Temporarily put the dynamic linker entry into the object list, so
2150 * that symbols can be found.
2152 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2154 ehdr = (Elf_Ehdr *)mapbase;
2155 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2156 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2158 /* Initialize the object list. */
2159 TAILQ_INIT(&obj_list);
2161 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2162 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2164 #ifndef RTLD_INIT_PAGESIZES_EARLY
2165 /* The page size is required by the dynamic memory allocator. */
2166 init_pagesizes(aux_info);
2169 if (aux_info[AT_OSRELDATE] != NULL)
2170 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2172 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2174 /* Replace the path with a dynamically allocated copy. */
2175 obj_rtld.path = xstrdup(ld_path_rtld);
2177 r_debug.r_brk = r_debug_state;
2178 r_debug.r_state = RT_CONSISTENT;
2182 * Retrieve the array of supported page sizes. The kernel provides the page
2183 * sizes in increasing order.
2186 init_pagesizes(Elf_Auxinfo **aux_info)
2188 static size_t psa[MAXPAGESIZES];
2192 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2194 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2195 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2198 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2201 /* As a fallback, retrieve the base page size. */
2202 size = sizeof(psa[0]);
2203 if (aux_info[AT_PAGESZ] != NULL) {
2204 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2208 mib[1] = HW_PAGESIZE;
2212 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2213 _rtld_error("sysctl for hw.pagesize(s) failed");
2219 npagesizes = size / sizeof(pagesizes[0]);
2220 /* Discard any invalid entries at the end of the array. */
2221 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2226 * Add the init functions from a needed object list (and its recursive
2227 * needed objects) to "list". This is not used directly; it is a helper
2228 * function for initlist_add_objects(). The write lock must be held
2229 * when this function is called.
2232 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2234 /* Recursively process the successor needed objects. */
2235 if (needed->next != NULL)
2236 initlist_add_neededs(needed->next, list);
2238 /* Process the current needed object. */
2239 if (needed->obj != NULL)
2240 initlist_add_objects(needed->obj, needed->obj, list);
2244 * Scan all of the DAGs rooted in the range of objects from "obj" to
2245 * "tail" and add their init functions to "list". This recurses over
2246 * the DAGs and ensure the proper init ordering such that each object's
2247 * needed libraries are initialized before the object itself. At the
2248 * same time, this function adds the objects to the global finalization
2249 * list "list_fini" in the opposite order. The write lock must be
2250 * held when this function is called.
2253 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2257 if (obj->init_scanned || obj->init_done)
2259 obj->init_scanned = true;
2261 /* Recursively process the successor objects. */
2262 nobj = globallist_next(obj);
2263 if (nobj != NULL && obj != tail)
2264 initlist_add_objects(nobj, tail, list);
2266 /* Recursively process the needed objects. */
2267 if (obj->needed != NULL)
2268 initlist_add_neededs(obj->needed, list);
2269 if (obj->needed_filtees != NULL)
2270 initlist_add_neededs(obj->needed_filtees, list);
2271 if (obj->needed_aux_filtees != NULL)
2272 initlist_add_neededs(obj->needed_aux_filtees, list);
2274 /* Add the object to the init list. */
2275 objlist_push_tail(list, obj);
2277 /* Add the object to the global fini list in the reverse order. */
2278 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2279 && !obj->on_fini_list) {
2280 objlist_push_head(&list_fini, obj);
2281 obj->on_fini_list = true;
2286 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2290 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2292 Needed_Entry *needed, *needed1;
2294 for (needed = n; needed != NULL; needed = needed->next) {
2295 if (needed->obj != NULL) {
2296 dlclose_locked(needed->obj, lockstate);
2300 for (needed = n; needed != NULL; needed = needed1) {
2301 needed1 = needed->next;
2307 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2310 free_needed_filtees(obj->needed_filtees, lockstate);
2311 obj->needed_filtees = NULL;
2312 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2313 obj->needed_aux_filtees = NULL;
2314 obj->filtees_loaded = false;
2318 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2319 RtldLockState *lockstate)
2322 for (; needed != NULL; needed = needed->next) {
2323 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2324 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2325 RTLD_LOCAL, lockstate);
2330 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2333 lock_restart_for_upgrade(lockstate);
2334 if (!obj->filtees_loaded) {
2335 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2336 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2337 obj->filtees_loaded = true;
2342 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2346 for (; needed != NULL; needed = needed->next) {
2347 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2348 flags & ~RTLD_LO_NOLOAD);
2349 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2356 * Given a shared object, traverse its list of needed objects, and load
2357 * each of them. Returns 0 on success. Generates an error message and
2358 * returns -1 on failure.
2361 load_needed_objects(Obj_Entry *first, int flags)
2365 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2368 if (process_needed(obj, obj->needed, flags) == -1)
2375 load_preload_objects(void)
2377 char *p = ld_preload;
2379 static const char delim[] = " \t:;";
2384 p += strspn(p, delim);
2385 while (*p != '\0') {
2386 size_t len = strcspn(p, delim);
2391 obj = load_object(p, -1, NULL, 0);
2393 return -1; /* XXX - cleanup */
2394 obj->z_interpose = true;
2397 p += strspn(p, delim);
2399 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2404 printable_path(const char *path)
2407 return (path == NULL ? "<unknown>" : path);
2411 * Load a shared object into memory, if it is not already loaded. The
2412 * object may be specified by name or by user-supplied file descriptor
2413 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2416 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2420 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2429 TAILQ_FOREACH(obj, &obj_list, next) {
2430 if (obj->marker || obj->doomed)
2432 if (object_match_name(obj, name))
2436 path = find_library(name, refobj, &fd);
2444 * search_library_pathfds() opens a fresh file descriptor for the
2445 * library, so there is no need to dup().
2447 } else if (fd_u == -1) {
2449 * If we didn't find a match by pathname, or the name is not
2450 * supplied, open the file and check again by device and inode.
2451 * This avoids false mismatches caused by multiple links or ".."
2454 * To avoid a race, we open the file and use fstat() rather than
2457 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2458 _rtld_error("Cannot open \"%s\"", path);
2463 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2465 _rtld_error("Cannot dup fd");
2470 if (fstat(fd, &sb) == -1) {
2471 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2476 TAILQ_FOREACH(obj, &obj_list, next) {
2477 if (obj->marker || obj->doomed)
2479 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2482 if (obj != NULL && name != NULL) {
2483 object_add_name(obj, name);
2488 if (flags & RTLD_LO_NOLOAD) {
2494 /* First use of this object, so we must map it in */
2495 obj = do_load_object(fd, name, path, &sb, flags);
2504 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2511 * but first, make sure that environment variables haven't been
2512 * used to circumvent the noexec flag on a filesystem.
2514 if (dangerous_ld_env) {
2515 if (fstatfs(fd, &fs) != 0) {
2516 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2519 if (fs.f_flags & MNT_NOEXEC) {
2520 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2524 dbg("loading \"%s\"", printable_path(path));
2525 obj = map_object(fd, printable_path(path), sbp);
2530 * If DT_SONAME is present in the object, digest_dynamic2 already
2531 * added it to the object names.
2534 object_add_name(obj, name);
2536 if (!digest_dynamic(obj, 0))
2539 _rtld_error("Cannot load PIE binary %s as DSO", obj->path);
2542 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2543 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2544 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2546 dbg("refusing to load non-loadable \"%s\"", obj->path);
2547 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2551 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2552 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2555 linkmap_add(obj); /* for GDB & dlinfo() */
2556 max_stack_flags |= obj->stack_flags;
2558 dbg(" %p .. %p: %s", obj->mapbase,
2559 obj->mapbase + obj->mapsize - 1, obj->path);
2561 dbg(" WARNING: %s has impure text", obj->path);
2562 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2568 munmap(obj->mapbase, obj->mapsize);
2574 obj_from_addr(const void *addr)
2578 TAILQ_FOREACH(obj, &obj_list, next) {
2581 if (addr < (void *) obj->mapbase)
2583 if (addr < (void *)(obj->mapbase + obj->mapsize))
2592 Elf_Addr *preinit_addr;
2595 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2596 if (preinit_addr == NULL)
2599 for (index = 0; index < obj_main->preinit_array_num; index++) {
2600 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2601 dbg("calling preinit function for %s at %p", obj_main->path,
2602 (void *)preinit_addr[index]);
2603 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2604 0, 0, obj_main->path);
2605 call_init_pointer(obj_main, preinit_addr[index]);
2611 * Call the finalization functions for each of the objects in "list"
2612 * belonging to the DAG of "root" and referenced once. If NULL "root"
2613 * is specified, every finalization function will be called regardless
2614 * of the reference count and the list elements won't be freed. All of
2615 * the objects are expected to have non-NULL fini functions.
2618 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2622 Elf_Addr *fini_addr;
2625 assert(root == NULL || root->refcount == 1);
2628 root->doomed = true;
2631 * Preserve the current error message since a fini function might
2632 * call into the dynamic linker and overwrite it.
2634 saved_msg = errmsg_save();
2636 STAILQ_FOREACH(elm, list, link) {
2637 if (root != NULL && (elm->obj->refcount != 1 ||
2638 objlist_find(&root->dagmembers, elm->obj) == NULL))
2640 /* Remove object from fini list to prevent recursive invocation. */
2641 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2642 /* Ensure that new references cannot be acquired. */
2643 elm->obj->doomed = true;
2645 hold_object(elm->obj);
2646 lock_release(rtld_bind_lock, lockstate);
2648 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2649 * When this happens, DT_FINI_ARRAY is processed first.
2651 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2652 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2653 for (index = elm->obj->fini_array_num - 1; index >= 0;
2655 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2656 dbg("calling fini function for %s at %p",
2657 elm->obj->path, (void *)fini_addr[index]);
2658 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2659 (void *)fini_addr[index], 0, 0, elm->obj->path);
2660 call_initfini_pointer(elm->obj, fini_addr[index]);
2664 if (elm->obj->fini != (Elf_Addr)NULL) {
2665 dbg("calling fini function for %s at %p", elm->obj->path,
2666 (void *)elm->obj->fini);
2667 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2668 0, 0, elm->obj->path);
2669 call_initfini_pointer(elm->obj, elm->obj->fini);
2671 wlock_acquire(rtld_bind_lock, lockstate);
2672 unhold_object(elm->obj);
2673 /* No need to free anything if process is going down. */
2677 * We must restart the list traversal after every fini call
2678 * because a dlclose() call from the fini function or from
2679 * another thread might have modified the reference counts.
2683 } while (elm != NULL);
2684 errmsg_restore(saved_msg);
2688 * Call the initialization functions for each of the objects in
2689 * "list". All of the objects are expected to have non-NULL init
2693 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2698 Elf_Addr *init_addr;
2699 void (*reg)(void (*)(void));
2703 * Clean init_scanned flag so that objects can be rechecked and
2704 * possibly initialized earlier if any of vectors called below
2705 * cause the change by using dlopen.
2707 TAILQ_FOREACH(obj, &obj_list, next) {
2710 obj->init_scanned = false;
2714 * Preserve the current error message since an init function might
2715 * call into the dynamic linker and overwrite it.
2717 saved_msg = errmsg_save();
2718 STAILQ_FOREACH(elm, list, link) {
2719 if (elm->obj->init_done) /* Initialized early. */
2722 * Race: other thread might try to use this object before current
2723 * one completes the initialization. Not much can be done here
2724 * without better locking.
2726 elm->obj->init_done = true;
2727 hold_object(elm->obj);
2729 if (elm->obj == obj_main && obj_main->crt_no_init) {
2730 reg = (void (*)(void (*)(void)))get_program_var_addr(
2731 "__libc_atexit", lockstate);
2733 lock_release(rtld_bind_lock, lockstate);
2736 rtld_exit_ptr = rtld_nop_exit;
2740 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2741 * When this happens, DT_INIT is processed first.
2743 if (elm->obj->init != (Elf_Addr)NULL) {
2744 dbg("calling init function for %s at %p", elm->obj->path,
2745 (void *)elm->obj->init);
2746 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2747 0, 0, elm->obj->path);
2748 call_initfini_pointer(elm->obj, elm->obj->init);
2750 init_addr = (Elf_Addr *)elm->obj->init_array;
2751 if (init_addr != NULL) {
2752 for (index = 0; index < elm->obj->init_array_num; index++) {
2753 if (init_addr[index] != 0 && init_addr[index] != 1) {
2754 dbg("calling init function for %s at %p", elm->obj->path,
2755 (void *)init_addr[index]);
2756 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2757 (void *)init_addr[index], 0, 0, elm->obj->path);
2758 call_init_pointer(elm->obj, init_addr[index]);
2762 wlock_acquire(rtld_bind_lock, lockstate);
2763 unhold_object(elm->obj);
2765 errmsg_restore(saved_msg);
2769 objlist_clear(Objlist *list)
2773 while (!STAILQ_EMPTY(list)) {
2774 elm = STAILQ_FIRST(list);
2775 STAILQ_REMOVE_HEAD(list, link);
2780 static Objlist_Entry *
2781 objlist_find(Objlist *list, const Obj_Entry *obj)
2785 STAILQ_FOREACH(elm, list, link)
2786 if (elm->obj == obj)
2792 objlist_init(Objlist *list)
2798 objlist_push_head(Objlist *list, Obj_Entry *obj)
2802 elm = NEW(Objlist_Entry);
2804 STAILQ_INSERT_HEAD(list, elm, link);
2808 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2812 elm = NEW(Objlist_Entry);
2814 STAILQ_INSERT_TAIL(list, elm, link);
2818 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2820 Objlist_Entry *elm, *listelm;
2822 STAILQ_FOREACH(listelm, list, link) {
2823 if (listelm->obj == listobj)
2826 elm = NEW(Objlist_Entry);
2828 if (listelm != NULL)
2829 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2831 STAILQ_INSERT_TAIL(list, elm, link);
2835 objlist_remove(Objlist *list, Obj_Entry *obj)
2839 if ((elm = objlist_find(list, obj)) != NULL) {
2840 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2846 * Relocate dag rooted in the specified object.
2847 * Returns 0 on success, or -1 on failure.
2851 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2852 int flags, RtldLockState *lockstate)
2858 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2859 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2868 * Prepare for, or clean after, relocating an object marked with
2869 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2870 * segments are remapped read-write. After relocations are done, the
2871 * segment's permissions are returned back to the modes specified in
2872 * the phdrs. If any relocation happened, or always for wired
2873 * program, COW is triggered.
2876 reloc_textrel_prot(Obj_Entry *obj, bool before)
2883 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2885 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2887 base = obj->relocbase + trunc_page(ph->p_vaddr);
2888 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2889 trunc_page(ph->p_vaddr);
2890 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2891 if (mprotect(base, sz, prot) == -1) {
2892 _rtld_error("%s: Cannot write-%sable text segment: %s",
2893 obj->path, before ? "en" : "dis",
2894 rtld_strerror(errno));
2902 * Relocate single object.
2903 * Returns 0 on success, or -1 on failure.
2906 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2907 int flags, RtldLockState *lockstate)
2912 obj->relocated = true;
2914 dbg("relocating \"%s\"", obj->path);
2916 if (obj->symtab == NULL || obj->strtab == NULL ||
2917 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2918 _rtld_error("%s: Shared object has no run-time symbol table",
2923 /* There are relocations to the write-protected text segment. */
2924 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2927 /* Process the non-PLT non-IFUNC relocations. */
2928 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2931 /* Re-protected the text segment. */
2932 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2935 /* Set the special PLT or GOT entries. */
2938 /* Process the PLT relocations. */
2939 if (reloc_plt(obj, flags, lockstate) == -1)
2941 /* Relocate the jump slots if we are doing immediate binding. */
2942 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
2946 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2950 * Set up the magic number and version in the Obj_Entry. These
2951 * were checked in the crt1.o from the original ElfKit, so we
2952 * set them for backward compatibility.
2954 obj->magic = RTLD_MAGIC;
2955 obj->version = RTLD_VERSION;
2961 * Relocate newly-loaded shared objects. The argument is a pointer to
2962 * the Obj_Entry for the first such object. All objects from the first
2963 * to the end of the list of objects are relocated. Returns 0 on success,
2967 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2968 int flags, RtldLockState *lockstate)
2973 for (error = 0, obj = first; obj != NULL;
2974 obj = TAILQ_NEXT(obj, next)) {
2977 error = relocate_object(obj, bind_now, rtldobj, flags,
2986 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2987 * referencing STT_GNU_IFUNC symbols is postponed till the other
2988 * relocations are done. The indirect functions specified as
2989 * ifunc are allowed to call other symbols, so we need to have
2990 * objects relocated before asking for resolution from indirects.
2992 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2993 * instead of the usual lazy handling of PLT slots. It is
2994 * consistent with how GNU does it.
2997 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2998 RtldLockState *lockstate)
3001 if (obj->ifuncs_resolved)
3003 obj->ifuncs_resolved = true;
3004 if (!obj->irelative && !obj->irelative_nonplt &&
3005 !((obj->bind_now || bind_now) && obj->gnu_ifunc))
3007 if (obj_disable_relro(obj) == -1 ||
3008 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3009 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj,
3010 lockstate) == -1) ||
3011 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3012 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3013 obj_enforce_relro(obj) == -1)
3019 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3020 RtldLockState *lockstate)
3025 STAILQ_FOREACH(elm, list, link) {
3029 if (resolve_object_ifunc(obj, bind_now, flags,
3037 * Cleanup procedure. It will be called (by the atexit mechanism) just
3038 * before the process exits.
3043 RtldLockState lockstate;
3045 wlock_acquire(rtld_bind_lock, &lockstate);
3047 objlist_call_fini(&list_fini, NULL, &lockstate);
3048 /* No need to remove the items from the list, since we are exiting. */
3049 if (!libmap_disable)
3051 lock_release(rtld_bind_lock, &lockstate);
3060 * Iterate over a search path, translate each element, and invoke the
3061 * callback on the result.
3064 path_enumerate(const char *path, path_enum_proc callback,
3065 const char *refobj_path, void *arg)
3071 path += strspn(path, ":;");
3072 while (*path != '\0') {
3076 len = strcspn(path, ":;");
3077 trans = lm_findn(refobj_path, path, len);
3079 res = callback(trans, strlen(trans), arg);
3081 res = callback(path, len, arg);
3087 path += strspn(path, ":;");
3093 struct try_library_args {
3102 try_library_path(const char *dir, size_t dirlen, void *param)
3104 struct try_library_args *arg;
3108 if (*dir == '/' || trust) {
3111 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3114 pathname = arg->buffer;
3115 strncpy(pathname, dir, dirlen);
3116 pathname[dirlen] = '/';
3117 strcpy(pathname + dirlen + 1, arg->name);
3119 dbg(" Trying \"%s\"", pathname);
3120 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3122 dbg(" Opened \"%s\", fd %d", pathname, fd);
3123 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3124 strcpy(pathname, arg->buffer);
3128 dbg(" Failed to open \"%s\": %s",
3129 pathname, rtld_strerror(errno));
3136 search_library_path(const char *name, const char *path,
3137 const char *refobj_path, int *fdp)
3140 struct try_library_args arg;
3146 arg.namelen = strlen(name);
3147 arg.buffer = xmalloc(PATH_MAX);
3148 arg.buflen = PATH_MAX;
3151 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3161 * Finds the library with the given name using the directory descriptors
3162 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3164 * Returns a freshly-opened close-on-exec file descriptor for the library,
3165 * or -1 if the library cannot be found.
3168 search_library_pathfds(const char *name, const char *path, int *fdp)
3170 char *envcopy, *fdstr, *found, *last_token;
3174 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3176 /* Don't load from user-specified libdirs into setuid binaries. */
3180 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3184 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3185 if (name[0] == '/') {
3186 dbg("Absolute path (%s) passed to %s", name, __func__);
3191 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3192 * copy of the path, as strtok_r rewrites separator tokens
3196 envcopy = xstrdup(path);
3197 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3198 fdstr = strtok_r(NULL, ":", &last_token)) {
3199 dirfd = parse_integer(fdstr);
3201 _rtld_error("failed to parse directory FD: '%s'",
3205 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3208 len = strlen(fdstr) + strlen(name) + 3;
3209 found = xmalloc(len);
3210 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3211 _rtld_error("error generating '%d/%s'",
3215 dbg("open('%s') => %d", found, fd);
3226 dlclose(void *handle)
3228 RtldLockState lockstate;
3231 wlock_acquire(rtld_bind_lock, &lockstate);
3232 error = dlclose_locked(handle, &lockstate);
3233 lock_release(rtld_bind_lock, &lockstate);
3238 dlclose_locked(void *handle, RtldLockState *lockstate)
3242 root = dlcheck(handle);
3245 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3248 /* Unreference the object and its dependencies. */
3249 root->dl_refcount--;
3251 if (root->refcount == 1) {
3253 * The object will be no longer referenced, so we must unload it.
3254 * First, call the fini functions.
3256 objlist_call_fini(&list_fini, root, lockstate);
3260 /* Finish cleaning up the newly-unreferenced objects. */
3261 GDB_STATE(RT_DELETE,&root->linkmap);
3262 unload_object(root, lockstate);
3263 GDB_STATE(RT_CONSISTENT,NULL);
3267 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3274 char *msg = error_message;
3275 error_message = NULL;
3280 * This function is deprecated and has no effect.
3283 dllockinit(void *context,
3284 void *(*_lock_create)(void *context) __unused,
3285 void (*_rlock_acquire)(void *lock) __unused,
3286 void (*_wlock_acquire)(void *lock) __unused,
3287 void (*_lock_release)(void *lock) __unused,
3288 void (*_lock_destroy)(void *lock) __unused,
3289 void (*context_destroy)(void *context))
3291 static void *cur_context;
3292 static void (*cur_context_destroy)(void *);
3294 /* Just destroy the context from the previous call, if necessary. */
3295 if (cur_context_destroy != NULL)
3296 cur_context_destroy(cur_context);
3297 cur_context = context;
3298 cur_context_destroy = context_destroy;
3302 dlopen(const char *name, int mode)
3305 return (rtld_dlopen(name, -1, mode));
3309 fdlopen(int fd, int mode)
3312 return (rtld_dlopen(NULL, fd, mode));
3316 rtld_dlopen(const char *name, int fd, int mode)
3318 RtldLockState lockstate;
3321 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3322 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3323 if (ld_tracing != NULL) {
3324 rlock_acquire(rtld_bind_lock, &lockstate);
3325 if (sigsetjmp(lockstate.env, 0) != 0)
3326 lock_upgrade(rtld_bind_lock, &lockstate);
3327 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3328 lock_release(rtld_bind_lock, &lockstate);
3330 lo_flags = RTLD_LO_DLOPEN;
3331 if (mode & RTLD_NODELETE)
3332 lo_flags |= RTLD_LO_NODELETE;
3333 if (mode & RTLD_NOLOAD)
3334 lo_flags |= RTLD_LO_NOLOAD;
3335 if (mode & RTLD_DEEPBIND)
3336 lo_flags |= RTLD_LO_DEEPBIND;
3337 if (ld_tracing != NULL)
3338 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3340 return (dlopen_object(name, fd, obj_main, lo_flags,
3341 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3345 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3350 if (obj->refcount == 0)
3351 unload_object(obj, lockstate);
3355 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3356 int mode, RtldLockState *lockstate)
3358 Obj_Entry *old_obj_tail;
3361 RtldLockState mlockstate;
3364 objlist_init(&initlist);
3366 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3367 wlock_acquire(rtld_bind_lock, &mlockstate);
3368 lockstate = &mlockstate;
3370 GDB_STATE(RT_ADD,NULL);
3372 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3374 if (name == NULL && fd == -1) {
3378 obj = load_object(name, fd, refobj, lo_flags);
3383 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3384 objlist_push_tail(&list_global, obj);
3385 if (globallist_next(old_obj_tail) != NULL) {
3386 /* We loaded something new. */
3387 assert(globallist_next(old_obj_tail) == obj);
3388 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
3389 obj->symbolic = true;
3391 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 &&
3392 obj->static_tls && !allocate_tls_offset(obj)) {
3393 _rtld_error("%s: No space available "
3394 "for static Thread Local Storage", obj->path);
3398 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3399 RTLD_LO_EARLY | RTLD_LO_IGNSTLS));
3403 result = rtld_verify_versions(&obj->dagmembers);
3404 if (result != -1 && ld_tracing)
3406 if (result == -1 || relocate_object_dag(obj,
3407 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3408 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3410 dlopen_cleanup(obj, lockstate);
3412 } else if (lo_flags & RTLD_LO_EARLY) {
3414 * Do not call the init functions for early loaded
3415 * filtees. The image is still not initialized enough
3418 * Our object is found by the global object list and
3419 * will be ordered among all init calls done right
3420 * before transferring control to main.
3423 /* Make list of init functions to call. */
3424 initlist_add_objects(obj, obj, &initlist);
3427 * Process all no_delete or global objects here, given
3428 * them own DAGs to prevent their dependencies from being
3429 * unloaded. This has to be done after we have loaded all
3430 * of the dependencies, so that we do not miss any.
3436 * Bump the reference counts for objects on this DAG. If
3437 * this is the first dlopen() call for the object that was
3438 * already loaded as a dependency, initialize the dag
3444 if ((lo_flags & RTLD_LO_TRACE) != 0)
3447 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3448 obj->z_nodelete) && !obj->ref_nodel) {
3449 dbg("obj %s nodelete", obj->path);
3451 obj->z_nodelete = obj->ref_nodel = true;
3455 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3457 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3459 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3460 map_stacks_exec(lockstate);
3462 distribute_static_tls(&initlist, lockstate);
3465 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3466 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3468 objlist_clear(&initlist);
3469 dlopen_cleanup(obj, lockstate);
3470 if (lockstate == &mlockstate)
3471 lock_release(rtld_bind_lock, lockstate);
3475 if (!(lo_flags & RTLD_LO_EARLY)) {
3476 /* Call the init functions. */
3477 objlist_call_init(&initlist, lockstate);
3479 objlist_clear(&initlist);
3480 if (lockstate == &mlockstate)
3481 lock_release(rtld_bind_lock, lockstate);
3484 trace_loaded_objects(obj);
3485 if (lockstate == &mlockstate)
3486 lock_release(rtld_bind_lock, lockstate);
3491 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3495 const Obj_Entry *obj, *defobj;
3498 RtldLockState lockstate;
3505 symlook_init(&req, name);
3507 req.flags = flags | SYMLOOK_IN_PLT;
3508 req.lockstate = &lockstate;
3510 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3511 rlock_acquire(rtld_bind_lock, &lockstate);
3512 if (sigsetjmp(lockstate.env, 0) != 0)
3513 lock_upgrade(rtld_bind_lock, &lockstate);
3514 if (handle == NULL || handle == RTLD_NEXT ||
3515 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3517 if ((obj = obj_from_addr(retaddr)) == NULL) {
3518 _rtld_error("Cannot determine caller's shared object");
3519 lock_release(rtld_bind_lock, &lockstate);
3520 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3523 if (handle == NULL) { /* Just the caller's shared object. */
3524 res = symlook_obj(&req, obj);
3527 defobj = req.defobj_out;
3529 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3530 handle == RTLD_SELF) { /* ... caller included */
3531 if (handle == RTLD_NEXT)
3532 obj = globallist_next(obj);
3533 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3536 res = symlook_obj(&req, obj);
3539 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3541 defobj = req.defobj_out;
3542 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3548 * Search the dynamic linker itself, and possibly resolve the
3549 * symbol from there. This is how the application links to
3550 * dynamic linker services such as dlopen.
3552 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3553 res = symlook_obj(&req, &obj_rtld);
3556 defobj = req.defobj_out;
3560 assert(handle == RTLD_DEFAULT);
3561 res = symlook_default(&req, obj);
3563 defobj = req.defobj_out;
3568 if ((obj = dlcheck(handle)) == NULL) {
3569 lock_release(rtld_bind_lock, &lockstate);
3570 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3574 donelist_init(&donelist);
3575 if (obj->mainprog) {
3576 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3577 res = symlook_global(&req, &donelist);
3580 defobj = req.defobj_out;
3583 * Search the dynamic linker itself, and possibly resolve the
3584 * symbol from there. This is how the application links to
3585 * dynamic linker services such as dlopen.
3587 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3588 res = symlook_obj(&req, &obj_rtld);
3591 defobj = req.defobj_out;
3596 /* Search the whole DAG rooted at the given object. */
3597 res = symlook_list(&req, &obj->dagmembers, &donelist);
3600 defobj = req.defobj_out;
3606 lock_release(rtld_bind_lock, &lockstate);
3609 * The value required by the caller is derived from the value
3610 * of the symbol. this is simply the relocated value of the
3613 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3614 sym = make_function_pointer(def, defobj);
3615 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3616 sym = rtld_resolve_ifunc(defobj, def);
3617 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3618 ti.ti_module = defobj->tlsindex;
3619 ti.ti_offset = def->st_value;
3620 sym = __tls_get_addr(&ti);
3622 sym = defobj->relocbase + def->st_value;
3623 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3627 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3628 ve != NULL ? ve->name : "");
3629 lock_release(rtld_bind_lock, &lockstate);
3630 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3635 dlsym(void *handle, const char *name)
3637 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3642 dlfunc(void *handle, const char *name)
3649 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3655 dlvsym(void *handle, const char *name, const char *version)
3659 ventry.name = version;
3661 ventry.hash = elf_hash(version);
3663 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3668 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3670 const Obj_Entry *obj;
3671 RtldLockState lockstate;
3673 rlock_acquire(rtld_bind_lock, &lockstate);
3674 obj = obj_from_addr(addr);
3676 _rtld_error("No shared object contains address");
3677 lock_release(rtld_bind_lock, &lockstate);
3680 rtld_fill_dl_phdr_info(obj, phdr_info);
3681 lock_release(rtld_bind_lock, &lockstate);
3686 dladdr(const void *addr, Dl_info *info)
3688 const Obj_Entry *obj;
3691 unsigned long symoffset;
3692 RtldLockState lockstate;
3694 rlock_acquire(rtld_bind_lock, &lockstate);
3695 obj = obj_from_addr(addr);
3697 _rtld_error("No shared object contains address");
3698 lock_release(rtld_bind_lock, &lockstate);
3701 info->dli_fname = obj->path;
3702 info->dli_fbase = obj->mapbase;
3703 info->dli_saddr = (void *)0;
3704 info->dli_sname = NULL;
3707 * Walk the symbol list looking for the symbol whose address is
3708 * closest to the address sent in.
3710 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3711 def = obj->symtab + symoffset;
3714 * For skip the symbol if st_shndx is either SHN_UNDEF or
3717 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3721 * If the symbol is greater than the specified address, or if it
3722 * is further away from addr than the current nearest symbol,
3725 symbol_addr = obj->relocbase + def->st_value;
3726 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3729 /* Update our idea of the nearest symbol. */
3730 info->dli_sname = obj->strtab + def->st_name;
3731 info->dli_saddr = symbol_addr;
3734 if (info->dli_saddr == addr)
3737 lock_release(rtld_bind_lock, &lockstate);
3742 dlinfo(void *handle, int request, void *p)
3744 const Obj_Entry *obj;
3745 RtldLockState lockstate;
3748 rlock_acquire(rtld_bind_lock, &lockstate);
3750 if (handle == NULL || handle == RTLD_SELF) {
3753 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3754 if ((obj = obj_from_addr(retaddr)) == NULL)
3755 _rtld_error("Cannot determine caller's shared object");
3757 obj = dlcheck(handle);
3760 lock_release(rtld_bind_lock, &lockstate);
3766 case RTLD_DI_LINKMAP:
3767 *((struct link_map const **)p) = &obj->linkmap;
3769 case RTLD_DI_ORIGIN:
3770 error = rtld_dirname(obj->path, p);
3773 case RTLD_DI_SERINFOSIZE:
3774 case RTLD_DI_SERINFO:
3775 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3779 _rtld_error("Invalid request %d passed to dlinfo()", request);
3783 lock_release(rtld_bind_lock, &lockstate);
3789 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3792 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3793 phdr_info->dlpi_name = obj->path;
3794 phdr_info->dlpi_phdr = obj->phdr;
3795 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3796 phdr_info->dlpi_tls_modid = obj->tlsindex;
3797 phdr_info->dlpi_tls_data = obj->tlsinit;
3798 phdr_info->dlpi_adds = obj_loads;
3799 phdr_info->dlpi_subs = obj_loads - obj_count;
3803 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3805 struct dl_phdr_info phdr_info;
3806 Obj_Entry *obj, marker;
3807 RtldLockState bind_lockstate, phdr_lockstate;
3810 init_marker(&marker);
3813 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3814 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3815 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3816 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3817 rtld_fill_dl_phdr_info(obj, &phdr_info);
3819 lock_release(rtld_bind_lock, &bind_lockstate);
3821 error = callback(&phdr_info, sizeof phdr_info, param);
3823 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3825 obj = globallist_next(&marker);
3826 TAILQ_REMOVE(&obj_list, &marker, next);
3828 lock_release(rtld_bind_lock, &bind_lockstate);
3829 lock_release(rtld_phdr_lock, &phdr_lockstate);
3835 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3836 lock_release(rtld_bind_lock, &bind_lockstate);
3837 error = callback(&phdr_info, sizeof(phdr_info), param);
3839 lock_release(rtld_phdr_lock, &phdr_lockstate);
3844 fill_search_info(const char *dir, size_t dirlen, void *param)
3846 struct fill_search_info_args *arg;
3850 if (arg->request == RTLD_DI_SERINFOSIZE) {
3851 arg->serinfo->dls_cnt ++;
3852 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3854 struct dl_serpath *s_entry;
3856 s_entry = arg->serpath;
3857 s_entry->dls_name = arg->strspace;
3858 s_entry->dls_flags = arg->flags;
3860 strncpy(arg->strspace, dir, dirlen);
3861 arg->strspace[dirlen] = '\0';
3863 arg->strspace += dirlen + 1;
3871 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3873 struct dl_serinfo _info;
3874 struct fill_search_info_args args;
3876 args.request = RTLD_DI_SERINFOSIZE;
3877 args.serinfo = &_info;
3879 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3882 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3883 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3884 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3885 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3886 if (!obj->z_nodeflib)
3887 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3890 if (request == RTLD_DI_SERINFOSIZE) {
3891 info->dls_size = _info.dls_size;
3892 info->dls_cnt = _info.dls_cnt;
3896 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3897 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3901 args.request = RTLD_DI_SERINFO;
3902 args.serinfo = info;
3903 args.serpath = &info->dls_serpath[0];
3904 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3906 args.flags = LA_SER_RUNPATH;
3907 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
3910 args.flags = LA_SER_LIBPATH;
3911 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
3914 args.flags = LA_SER_RUNPATH;
3915 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
3918 args.flags = LA_SER_CONFIG;
3919 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
3923 args.flags = LA_SER_DEFAULT;
3924 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
3925 fill_search_info, NULL, &args) != NULL)
3931 rtld_dirname(const char *path, char *bname)
3935 /* Empty or NULL string gets treated as "." */
3936 if (path == NULL || *path == '\0') {
3942 /* Strip trailing slashes */
3943 endp = path + strlen(path) - 1;
3944 while (endp > path && *endp == '/')
3947 /* Find the start of the dir */
3948 while (endp > path && *endp != '/')
3951 /* Either the dir is "/" or there are no slashes */
3953 bname[0] = *endp == '/' ? '/' : '.';
3959 } while (endp > path && *endp == '/');
3962 if (endp - path + 2 > PATH_MAX)
3964 _rtld_error("Filename is too long: %s", path);
3968 strncpy(bname, path, endp - path + 1);
3969 bname[endp - path + 1] = '\0';
3974 rtld_dirname_abs(const char *path, char *base)
3978 if (realpath(path, base) == NULL) {
3979 _rtld_error("realpath \"%s\" failed (%s)", path,
3980 rtld_strerror(errno));
3983 dbg("%s -> %s", path, base);
3984 last = strrchr(base, '/');
3986 _rtld_error("non-abs result from realpath \"%s\"", path);
3995 linkmap_add(Obj_Entry *obj)
3997 struct link_map *l, *prev;
4000 l->l_name = obj->path;
4001 l->l_base = obj->mapbase;
4002 l->l_ld = obj->dynamic;
4003 l->l_addr = obj->relocbase;
4005 if (r_debug.r_map == NULL) {
4011 * Scan to the end of the list, but not past the entry for the
4012 * dynamic linker, which we want to keep at the very end.
4014 for (prev = r_debug.r_map;
4015 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4016 prev = prev->l_next)
4019 /* Link in the new entry. */
4021 l->l_next = prev->l_next;
4022 if (l->l_next != NULL)
4023 l->l_next->l_prev = l;
4028 linkmap_delete(Obj_Entry *obj)
4033 if (l->l_prev == NULL) {
4034 if ((r_debug.r_map = l->l_next) != NULL)
4035 l->l_next->l_prev = NULL;
4039 if ((l->l_prev->l_next = l->l_next) != NULL)
4040 l->l_next->l_prev = l->l_prev;
4044 * Function for the debugger to set a breakpoint on to gain control.
4046 * The two parameters allow the debugger to easily find and determine
4047 * what the runtime loader is doing and to whom it is doing it.
4049 * When the loadhook trap is hit (r_debug_state, set at program
4050 * initialization), the arguments can be found on the stack:
4052 * +8 struct link_map *m
4053 * +4 struct r_debug *rd
4057 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4060 * The following is a hack to force the compiler to emit calls to
4061 * this function, even when optimizing. If the function is empty,
4062 * the compiler is not obliged to emit any code for calls to it,
4063 * even when marked __noinline. However, gdb depends on those
4066 __compiler_membar();
4070 * A function called after init routines have completed. This can be used to
4071 * break before a program's entry routine is called, and can be used when
4072 * main is not available in the symbol table.
4075 _r_debug_postinit(struct link_map *m __unused)
4078 /* See r_debug_state(). */
4079 __compiler_membar();
4083 release_object(Obj_Entry *obj)
4086 if (obj->holdcount > 0) {
4087 obj->unholdfree = true;
4090 munmap(obj->mapbase, obj->mapsize);
4091 linkmap_delete(obj);
4096 * Get address of the pointer variable in the main program.
4097 * Prefer non-weak symbol over the weak one.
4099 static const void **
4100 get_program_var_addr(const char *name, RtldLockState *lockstate)
4105 symlook_init(&req, name);
4106 req.lockstate = lockstate;
4107 donelist_init(&donelist);
4108 if (symlook_global(&req, &donelist) != 0)
4110 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4111 return ((const void **)make_function_pointer(req.sym_out,
4113 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4114 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4116 return ((const void **)(req.defobj_out->relocbase +
4117 req.sym_out->st_value));
4121 * Set a pointer variable in the main program to the given value. This
4122 * is used to set key variables such as "environ" before any of the
4123 * init functions are called.
4126 set_program_var(const char *name, const void *value)
4130 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4131 dbg("\"%s\": *%p <-- %p", name, addr, value);
4137 * Search the global objects, including dependencies and main object,
4138 * for the given symbol.
4141 symlook_global(SymLook *req, DoneList *donelist)
4144 const Objlist_Entry *elm;
4147 symlook_init_from_req(&req1, req);
4149 /* Search all objects loaded at program start up. */
4150 if (req->defobj_out == NULL ||
4151 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4152 res = symlook_list(&req1, &list_main, donelist);
4153 if (res == 0 && (req->defobj_out == NULL ||
4154 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4155 req->sym_out = req1.sym_out;
4156 req->defobj_out = req1.defobj_out;
4157 assert(req->defobj_out != NULL);
4161 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4162 STAILQ_FOREACH(elm, &list_global, link) {
4163 if (req->defobj_out != NULL &&
4164 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4166 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4167 if (res == 0 && (req->defobj_out == NULL ||
4168 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4169 req->sym_out = req1.sym_out;
4170 req->defobj_out = req1.defobj_out;
4171 assert(req->defobj_out != NULL);
4175 return (req->sym_out != NULL ? 0 : ESRCH);
4179 * Given a symbol name in a referencing object, find the corresponding
4180 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4181 * no definition was found. Returns a pointer to the Obj_Entry of the
4182 * defining object via the reference parameter DEFOBJ_OUT.
4185 symlook_default(SymLook *req, const Obj_Entry *refobj)
4188 const Objlist_Entry *elm;
4192 donelist_init(&donelist);
4193 symlook_init_from_req(&req1, req);
4196 * Look first in the referencing object if linked symbolically,
4197 * and similarly handle protected symbols.
4199 res = symlook_obj(&req1, refobj);
4200 if (res == 0 && (refobj->symbolic ||
4201 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4202 req->sym_out = req1.sym_out;
4203 req->defobj_out = req1.defobj_out;
4204 assert(req->defobj_out != NULL);
4206 if (refobj->symbolic || req->defobj_out != NULL)
4207 donelist_check(&donelist, refobj);
4209 symlook_global(req, &donelist);
4211 /* Search all dlopened DAGs containing the referencing object. */
4212 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4213 if (req->sym_out != NULL &&
4214 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4216 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4217 if (res == 0 && (req->sym_out == NULL ||
4218 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4219 req->sym_out = req1.sym_out;
4220 req->defobj_out = req1.defobj_out;
4221 assert(req->defobj_out != NULL);
4226 * Search the dynamic linker itself, and possibly resolve the
4227 * symbol from there. This is how the application links to
4228 * dynamic linker services such as dlopen.
4230 if (req->sym_out == NULL ||
4231 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4232 res = symlook_obj(&req1, &obj_rtld);
4234 req->sym_out = req1.sym_out;
4235 req->defobj_out = req1.defobj_out;
4236 assert(req->defobj_out != NULL);
4240 return (req->sym_out != NULL ? 0 : ESRCH);
4244 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4247 const Obj_Entry *defobj;
4248 const Objlist_Entry *elm;
4254 STAILQ_FOREACH(elm, objlist, link) {
4255 if (donelist_check(dlp, elm->obj))
4257 symlook_init_from_req(&req1, req);
4258 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4259 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4261 defobj = req1.defobj_out;
4262 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4269 req->defobj_out = defobj;
4276 * Search the chain of DAGS cointed to by the given Needed_Entry
4277 * for a symbol of the given name. Each DAG is scanned completely
4278 * before advancing to the next one. Returns a pointer to the symbol,
4279 * or NULL if no definition was found.
4282 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4285 const Needed_Entry *n;
4286 const Obj_Entry *defobj;
4292 symlook_init_from_req(&req1, req);
4293 for (n = needed; n != NULL; n = n->next) {
4294 if (n->obj == NULL ||
4295 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4297 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4299 defobj = req1.defobj_out;
4300 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4306 req->defobj_out = defobj;
4313 * Search the symbol table of a single shared object for a symbol of
4314 * the given name and version, if requested. Returns a pointer to the
4315 * symbol, or NULL if no definition was found. If the object is
4316 * filter, return filtered symbol from filtee.
4318 * The symbol's hash value is passed in for efficiency reasons; that
4319 * eliminates many recomputations of the hash value.
4322 symlook_obj(SymLook *req, const Obj_Entry *obj)
4326 int flags, res, mres;
4329 * If there is at least one valid hash at this point, we prefer to
4330 * use the faster GNU version if available.
4332 if (obj->valid_hash_gnu)
4333 mres = symlook_obj1_gnu(req, obj);
4334 else if (obj->valid_hash_sysv)
4335 mres = symlook_obj1_sysv(req, obj);
4340 if (obj->needed_filtees != NULL) {
4341 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4342 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4343 donelist_init(&donelist);
4344 symlook_init_from_req(&req1, req);
4345 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4347 req->sym_out = req1.sym_out;
4348 req->defobj_out = req1.defobj_out;
4352 if (obj->needed_aux_filtees != NULL) {
4353 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4354 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4355 donelist_init(&donelist);
4356 symlook_init_from_req(&req1, req);
4357 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4359 req->sym_out = req1.sym_out;
4360 req->defobj_out = req1.defobj_out;
4368 /* Symbol match routine common to both hash functions */
4370 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4371 const unsigned long symnum)
4374 const Elf_Sym *symp;
4377 symp = obj->symtab + symnum;
4378 strp = obj->strtab + symp->st_name;
4380 switch (ELF_ST_TYPE(symp->st_info)) {
4386 if (symp->st_value == 0)
4390 if (symp->st_shndx != SHN_UNDEF)
4393 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4394 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4401 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4404 if (req->ventry == NULL) {
4405 if (obj->versyms != NULL) {
4406 verndx = VER_NDX(obj->versyms[symnum]);
4407 if (verndx > obj->vernum) {
4409 "%s: symbol %s references wrong version %d",
4410 obj->path, obj->strtab + symnum, verndx);
4414 * If we are not called from dlsym (i.e. this
4415 * is a normal relocation from unversioned
4416 * binary), accept the symbol immediately if
4417 * it happens to have first version after this
4418 * shared object became versioned. Otherwise,
4419 * if symbol is versioned and not hidden,
4420 * remember it. If it is the only symbol with
4421 * this name exported by the shared object, it
4422 * will be returned as a match by the calling
4423 * function. If symbol is global (verndx < 2)
4424 * accept it unconditionally.
4426 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4427 verndx == VER_NDX_GIVEN) {
4428 result->sym_out = symp;
4431 else if (verndx >= VER_NDX_GIVEN) {
4432 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4434 if (result->vsymp == NULL)
4435 result->vsymp = symp;
4441 result->sym_out = symp;
4444 if (obj->versyms == NULL) {
4445 if (object_match_name(obj, req->ventry->name)) {
4446 _rtld_error("%s: object %s should provide version %s "
4447 "for symbol %s", obj_rtld.path, obj->path,
4448 req->ventry->name, obj->strtab + symnum);
4452 verndx = VER_NDX(obj->versyms[symnum]);
4453 if (verndx > obj->vernum) {
4454 _rtld_error("%s: symbol %s references wrong version %d",
4455 obj->path, obj->strtab + symnum, verndx);
4458 if (obj->vertab[verndx].hash != req->ventry->hash ||
4459 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4461 * Version does not match. Look if this is a
4462 * global symbol and if it is not hidden. If
4463 * global symbol (verndx < 2) is available,
4464 * use it. Do not return symbol if we are
4465 * called by dlvsym, because dlvsym looks for
4466 * a specific version and default one is not
4467 * what dlvsym wants.
4469 if ((req->flags & SYMLOOK_DLSYM) ||
4470 (verndx >= VER_NDX_GIVEN) ||
4471 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4475 result->sym_out = symp;
4480 * Search for symbol using SysV hash function.
4481 * obj->buckets is known not to be NULL at this point; the test for this was
4482 * performed with the obj->valid_hash_sysv assignment.
4485 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4487 unsigned long symnum;
4488 Sym_Match_Result matchres;
4490 matchres.sym_out = NULL;
4491 matchres.vsymp = NULL;
4492 matchres.vcount = 0;
4494 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4495 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4496 if (symnum >= obj->nchains)
4497 return (ESRCH); /* Bad object */
4499 if (matched_symbol(req, obj, &matchres, symnum)) {
4500 req->sym_out = matchres.sym_out;
4501 req->defobj_out = obj;
4505 if (matchres.vcount == 1) {
4506 req->sym_out = matchres.vsymp;
4507 req->defobj_out = obj;
4513 /* Search for symbol using GNU hash function */
4515 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4517 Elf_Addr bloom_word;
4518 const Elf32_Word *hashval;
4520 Sym_Match_Result matchres;
4521 unsigned int h1, h2;
4522 unsigned long symnum;
4524 matchres.sym_out = NULL;
4525 matchres.vsymp = NULL;
4526 matchres.vcount = 0;
4528 /* Pick right bitmask word from Bloom filter array */
4529 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4530 obj->maskwords_bm_gnu];
4532 /* Calculate modulus word size of gnu hash and its derivative */
4533 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4534 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4536 /* Filter out the "definitely not in set" queries */
4537 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4540 /* Locate hash chain and corresponding value element*/
4541 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4544 hashval = &obj->chain_zero_gnu[bucket];
4546 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4547 symnum = hashval - obj->chain_zero_gnu;
4548 if (matched_symbol(req, obj, &matchres, symnum)) {
4549 req->sym_out = matchres.sym_out;
4550 req->defobj_out = obj;
4554 } while ((*hashval++ & 1) == 0);
4555 if (matchres.vcount == 1) {
4556 req->sym_out = matchres.vsymp;
4557 req->defobj_out = obj;
4564 trace_loaded_objects(Obj_Entry *obj)
4566 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4569 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4572 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4573 fmt1 = "\t%o => %p (%x)\n";
4575 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4576 fmt2 = "\t%o (%x)\n";
4578 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4580 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4581 Needed_Entry *needed;
4582 const char *name, *path;
4587 if (list_containers && obj->needed != NULL)
4588 rtld_printf("%s:\n", obj->path);
4589 for (needed = obj->needed; needed; needed = needed->next) {
4590 if (needed->obj != NULL) {
4591 if (needed->obj->traced && !list_containers)
4593 needed->obj->traced = true;
4594 path = needed->obj->path;
4598 name = obj->strtab + needed->name;
4599 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4601 fmt = is_lib ? fmt1 : fmt2;
4602 while ((c = *fmt++) != '\0') {
4628 rtld_putstr(main_local);
4631 rtld_putstr(obj_main->path);
4638 rtld_printf("%d", sodp->sod_major);
4641 rtld_printf("%d", sodp->sod_minor);
4648 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4661 * Unload a dlopened object and its dependencies from memory and from
4662 * our data structures. It is assumed that the DAG rooted in the
4663 * object has already been unreferenced, and that the object has a
4664 * reference count of 0.
4667 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4669 Obj_Entry marker, *obj, *next;
4671 assert(root->refcount == 0);
4674 * Pass over the DAG removing unreferenced objects from
4675 * appropriate lists.
4677 unlink_object(root);
4679 /* Unmap all objects that are no longer referenced. */
4680 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4681 next = TAILQ_NEXT(obj, next);
4682 if (obj->marker || obj->refcount != 0)
4684 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4685 obj->mapsize, 0, obj->path);
4686 dbg("unloading \"%s\"", obj->path);
4688 * Unlink the object now to prevent new references from
4689 * being acquired while the bind lock is dropped in
4690 * recursive dlclose() invocations.
4692 TAILQ_REMOVE(&obj_list, obj, next);
4695 if (obj->filtees_loaded) {
4697 init_marker(&marker);
4698 TAILQ_INSERT_BEFORE(next, &marker, next);
4699 unload_filtees(obj, lockstate);
4700 next = TAILQ_NEXT(&marker, next);
4701 TAILQ_REMOVE(&obj_list, &marker, next);
4703 unload_filtees(obj, lockstate);
4705 release_object(obj);
4710 unlink_object(Obj_Entry *root)
4714 if (root->refcount == 0) {
4715 /* Remove the object from the RTLD_GLOBAL list. */
4716 objlist_remove(&list_global, root);
4718 /* Remove the object from all objects' DAG lists. */
4719 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4720 objlist_remove(&elm->obj->dldags, root);
4721 if (elm->obj != root)
4722 unlink_object(elm->obj);
4728 ref_dag(Obj_Entry *root)
4732 assert(root->dag_inited);
4733 STAILQ_FOREACH(elm, &root->dagmembers, link)
4734 elm->obj->refcount++;
4738 unref_dag(Obj_Entry *root)
4742 assert(root->dag_inited);
4743 STAILQ_FOREACH(elm, &root->dagmembers, link)
4744 elm->obj->refcount--;
4748 * Common code for MD __tls_get_addr().
4750 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4752 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4754 Elf_Addr *newdtv, *dtv;
4755 RtldLockState lockstate;
4759 /* Check dtv generation in case new modules have arrived */
4760 if (dtv[0] != tls_dtv_generation) {
4761 wlock_acquire(rtld_bind_lock, &lockstate);
4762 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4764 if (to_copy > tls_max_index)
4765 to_copy = tls_max_index;
4766 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4767 newdtv[0] = tls_dtv_generation;
4768 newdtv[1] = tls_max_index;
4770 lock_release(rtld_bind_lock, &lockstate);
4771 dtv = *dtvp = newdtv;
4774 /* Dynamically allocate module TLS if necessary */
4775 if (dtv[index + 1] == 0) {
4776 /* Signal safe, wlock will block out signals. */
4777 wlock_acquire(rtld_bind_lock, &lockstate);
4778 if (!dtv[index + 1])
4779 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4780 lock_release(rtld_bind_lock, &lockstate);
4782 return ((void *)(dtv[index + 1] + offset));
4786 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4791 /* Check dtv generation in case new modules have arrived */
4792 if (__predict_true(dtv[0] == tls_dtv_generation &&
4793 dtv[index + 1] != 0))
4794 return ((void *)(dtv[index + 1] + offset));
4795 return (tls_get_addr_slow(dtvp, index, offset));
4798 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4799 defined(__powerpc__) || defined(__riscv)
4802 * Return pointer to allocated TLS block
4805 get_tls_block_ptr(void *tcb, size_t tcbsize)
4807 size_t extra_size, post_size, pre_size, tls_block_size;
4808 size_t tls_init_align;
4810 tls_init_align = MAX(obj_main->tlsalign, 1);
4812 /* Compute fragments sizes. */
4813 extra_size = tcbsize - TLS_TCB_SIZE;
4814 post_size = calculate_tls_post_size(tls_init_align);
4815 tls_block_size = tcbsize + post_size;
4816 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4818 return ((char *)tcb - pre_size - extra_size);
4822 * Allocate Static TLS using the Variant I method.
4824 * For details on the layout, see lib/libc/gen/tls.c.
4826 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4827 * it is based on tls_last_offset, and TLS offsets here are really TCB
4828 * offsets, whereas libc's tls_static_space is just the executable's static
4832 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4836 Elf_Addr *dtv, **tcb;
4839 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4840 size_t tls_init_align, tls_init_offset;
4842 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4845 assert(tcbsize >= TLS_TCB_SIZE);
4846 maxalign = MAX(tcbalign, tls_static_max_align);
4847 tls_init_align = MAX(obj_main->tlsalign, 1);
4849 /* Compute fragmets sizes. */
4850 extra_size = tcbsize - TLS_TCB_SIZE;
4851 post_size = calculate_tls_post_size(tls_init_align);
4852 tls_block_size = tcbsize + post_size;
4853 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4854 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4856 /* Allocate whole TLS block */
4857 tls_block = malloc_aligned(tls_block_size, maxalign, 0);
4858 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4860 if (oldtcb != NULL) {
4861 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4863 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4865 /* Adjust the DTV. */
4867 for (i = 0; i < dtv[1]; i++) {
4868 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4869 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4870 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4874 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4876 dtv[0] = tls_dtv_generation;
4877 dtv[1] = tls_max_index;
4879 for (obj = globallist_curr(objs); obj != NULL;
4880 obj = globallist_next(obj)) {
4881 if (obj->tlsoffset == 0)
4883 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
4884 addr = (Elf_Addr)tcb + obj->tlsoffset;
4885 if (tls_init_offset > 0)
4886 memset((void *)addr, 0, tls_init_offset);
4887 if (obj->tlsinitsize > 0) {
4888 memcpy((void *)(addr + tls_init_offset), obj->tlsinit,
4891 if (obj->tlssize > obj->tlsinitsize) {
4892 memset((void *)(addr + tls_init_offset + obj->tlsinitsize),
4893 0, obj->tlssize - obj->tlsinitsize - tls_init_offset);
4895 dtv[obj->tlsindex + 1] = addr;
4903 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
4906 Elf_Addr tlsstart, tlsend;
4908 size_t dtvsize, i, tls_init_align;
4910 assert(tcbsize >= TLS_TCB_SIZE);
4911 tls_init_align = MAX(obj_main->tlsalign, 1);
4913 /* Compute fragments sizes. */
4914 post_size = calculate_tls_post_size(tls_init_align);
4916 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
4917 tlsend = (Elf_Addr)tcb + tls_static_space;
4919 dtv = *(Elf_Addr **)tcb;
4921 for (i = 0; i < dtvsize; i++) {
4922 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4923 free((void*)dtv[i+2]);
4927 free_aligned(get_tls_block_ptr(tcb, tcbsize));
4932 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4935 * Allocate Static TLS using the Variant II method.
4938 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4941 size_t size, ralign;
4943 Elf_Addr *dtv, *olddtv;
4944 Elf_Addr segbase, oldsegbase, addr;
4948 if (tls_static_max_align > ralign)
4949 ralign = tls_static_max_align;
4950 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
4952 assert(tcbsize >= 2*sizeof(Elf_Addr));
4953 tls = malloc_aligned(size, ralign, 0 /* XXX */);
4954 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4956 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign));
4957 ((Elf_Addr*)segbase)[0] = segbase;
4958 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4960 dtv[0] = tls_dtv_generation;
4961 dtv[1] = tls_max_index;
4965 * Copy the static TLS block over whole.
4967 oldsegbase = (Elf_Addr) oldtls;
4968 memcpy((void *)(segbase - tls_static_space),
4969 (const void *)(oldsegbase - tls_static_space),
4973 * If any dynamic TLS blocks have been created tls_get_addr(),
4976 olddtv = ((Elf_Addr**)oldsegbase)[1];
4977 for (i = 0; i < olddtv[1]; i++) {
4978 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4979 dtv[i+2] = olddtv[i+2];
4985 * We assume that this block was the one we created with
4986 * allocate_initial_tls().
4988 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4990 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4991 if (obj->marker || obj->tlsoffset == 0)
4993 addr = segbase - obj->tlsoffset;
4994 memset((void*)(addr + obj->tlsinitsize),
4995 0, obj->tlssize - obj->tlsinitsize);
4997 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4998 obj->static_tls_copied = true;
5000 dtv[obj->tlsindex + 1] = addr;
5004 return (void*) segbase;
5008 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
5011 size_t size, ralign;
5013 Elf_Addr tlsstart, tlsend;
5016 * Figure out the size of the initial TLS block so that we can
5017 * find stuff which ___tls_get_addr() allocated dynamically.
5020 if (tls_static_max_align > ralign)
5021 ralign = tls_static_max_align;
5022 size = roundup(tls_static_space, ralign);
5024 dtv = ((Elf_Addr**)tls)[1];
5026 tlsend = (Elf_Addr) tls;
5027 tlsstart = tlsend - size;
5028 for (i = 0; i < dtvsize; i++) {
5029 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
5030 free_aligned((void *)dtv[i + 2]);
5034 free_aligned((void *)tlsstart);
5041 * Allocate TLS block for module with given index.
5044 allocate_module_tls(int index)
5049 TAILQ_FOREACH(obj, &obj_list, next) {
5052 if (obj->tlsindex == index)
5056 _rtld_error("Can't find module with TLS index %d", index);
5060 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5061 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5062 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5067 allocate_tls_offset(Obj_Entry *obj)
5074 if (obj->tlssize == 0) {
5075 obj->tls_done = true;
5079 if (tls_last_offset == 0)
5080 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign,
5083 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5084 obj->tlssize, obj->tlsalign, obj->tlspoffset);
5087 * If we have already fixed the size of the static TLS block, we
5088 * must stay within that size. When allocating the static TLS, we
5089 * leave a small amount of space spare to be used for dynamically
5090 * loading modules which use static TLS.
5092 if (tls_static_space != 0) {
5093 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5095 } else if (obj->tlsalign > tls_static_max_align) {
5096 tls_static_max_align = obj->tlsalign;
5099 tls_last_offset = obj->tlsoffset = off;
5100 tls_last_size = obj->tlssize;
5101 obj->tls_done = true;
5107 free_tls_offset(Obj_Entry *obj)
5111 * If we were the last thing to allocate out of the static TLS
5112 * block, we give our space back to the 'allocator'. This is a
5113 * simplistic workaround to allow libGL.so.1 to be loaded and
5114 * unloaded multiple times.
5116 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5117 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5118 tls_last_offset -= obj->tlssize;
5124 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5127 RtldLockState lockstate;
5129 wlock_acquire(rtld_bind_lock, &lockstate);
5130 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5132 lock_release(rtld_bind_lock, &lockstate);
5137 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5139 RtldLockState lockstate;
5141 wlock_acquire(rtld_bind_lock, &lockstate);
5142 free_tls(tcb, tcbsize, tcbalign);
5143 lock_release(rtld_bind_lock, &lockstate);
5147 object_add_name(Obj_Entry *obj, const char *name)
5153 entry = malloc(sizeof(Name_Entry) + len);
5155 if (entry != NULL) {
5156 strcpy(entry->name, name);
5157 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5162 object_match_name(const Obj_Entry *obj, const char *name)
5166 STAILQ_FOREACH(entry, &obj->names, link) {
5167 if (strcmp(name, entry->name) == 0)
5174 locate_dependency(const Obj_Entry *obj, const char *name)
5176 const Objlist_Entry *entry;
5177 const Needed_Entry *needed;
5179 STAILQ_FOREACH(entry, &list_main, link) {
5180 if (object_match_name(entry->obj, name))
5184 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5185 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5186 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5188 * If there is DT_NEEDED for the name we are looking for,
5189 * we are all set. Note that object might not be found if
5190 * dependency was not loaded yet, so the function can
5191 * return NULL here. This is expected and handled
5192 * properly by the caller.
5194 return (needed->obj);
5197 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5203 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5204 const Elf_Vernaux *vna)
5206 const Elf_Verdef *vd;
5207 const char *vername;
5209 vername = refobj->strtab + vna->vna_name;
5210 vd = depobj->verdef;
5212 _rtld_error("%s: version %s required by %s not defined",
5213 depobj->path, vername, refobj->path);
5217 if (vd->vd_version != VER_DEF_CURRENT) {
5218 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5219 depobj->path, vd->vd_version);
5222 if (vna->vna_hash == vd->vd_hash) {
5223 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5224 ((const char *)vd + vd->vd_aux);
5225 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5228 if (vd->vd_next == 0)
5230 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5232 if (vna->vna_flags & VER_FLG_WEAK)
5234 _rtld_error("%s: version %s required by %s not found",
5235 depobj->path, vername, refobj->path);
5240 rtld_verify_object_versions(Obj_Entry *obj)
5242 const Elf_Verneed *vn;
5243 const Elf_Verdef *vd;
5244 const Elf_Verdaux *vda;
5245 const Elf_Vernaux *vna;
5246 const Obj_Entry *depobj;
5247 int maxvernum, vernum;
5249 if (obj->ver_checked)
5251 obj->ver_checked = true;
5255 * Walk over defined and required version records and figure out
5256 * max index used by any of them. Do very basic sanity checking
5260 while (vn != NULL) {
5261 if (vn->vn_version != VER_NEED_CURRENT) {
5262 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5263 obj->path, vn->vn_version);
5266 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5268 vernum = VER_NEED_IDX(vna->vna_other);
5269 if (vernum > maxvernum)
5271 if (vna->vna_next == 0)
5273 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5275 if (vn->vn_next == 0)
5277 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5281 while (vd != NULL) {
5282 if (vd->vd_version != VER_DEF_CURRENT) {
5283 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5284 obj->path, vd->vd_version);
5287 vernum = VER_DEF_IDX(vd->vd_ndx);
5288 if (vernum > maxvernum)
5290 if (vd->vd_next == 0)
5292 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5299 * Store version information in array indexable by version index.
5300 * Verify that object version requirements are satisfied along the
5303 obj->vernum = maxvernum + 1;
5304 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5307 while (vd != NULL) {
5308 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5309 vernum = VER_DEF_IDX(vd->vd_ndx);
5310 assert(vernum <= maxvernum);
5311 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5312 obj->vertab[vernum].hash = vd->vd_hash;
5313 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5314 obj->vertab[vernum].file = NULL;
5315 obj->vertab[vernum].flags = 0;
5317 if (vd->vd_next == 0)
5319 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5323 while (vn != NULL) {
5324 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5327 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5329 if (check_object_provided_version(obj, depobj, vna))
5331 vernum = VER_NEED_IDX(vna->vna_other);
5332 assert(vernum <= maxvernum);
5333 obj->vertab[vernum].hash = vna->vna_hash;
5334 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5335 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5336 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5337 VER_INFO_HIDDEN : 0;
5338 if (vna->vna_next == 0)
5340 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5342 if (vn->vn_next == 0)
5344 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5350 rtld_verify_versions(const Objlist *objlist)
5352 Objlist_Entry *entry;
5356 STAILQ_FOREACH(entry, objlist, link) {
5358 * Skip dummy objects or objects that have their version requirements
5361 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5363 if (rtld_verify_object_versions(entry->obj) == -1) {
5365 if (ld_tracing == NULL)
5369 if (rc == 0 || ld_tracing != NULL)
5370 rc = rtld_verify_object_versions(&obj_rtld);
5375 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5380 vernum = VER_NDX(obj->versyms[symnum]);
5381 if (vernum >= obj->vernum) {
5382 _rtld_error("%s: symbol %s has wrong verneed value %d",
5383 obj->path, obj->strtab + symnum, vernum);
5384 } else if (obj->vertab[vernum].hash != 0) {
5385 return &obj->vertab[vernum];
5392 _rtld_get_stack_prot(void)
5395 return (stack_prot);
5399 _rtld_is_dlopened(void *arg)
5402 RtldLockState lockstate;
5405 rlock_acquire(rtld_bind_lock, &lockstate);
5408 obj = obj_from_addr(arg);
5410 _rtld_error("No shared object contains address");
5411 lock_release(rtld_bind_lock, &lockstate);
5414 res = obj->dlopened ? 1 : 0;
5415 lock_release(rtld_bind_lock, &lockstate);
5420 obj_remap_relro(Obj_Entry *obj, int prot)
5423 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5425 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5426 obj->path, prot, rtld_strerror(errno));
5433 obj_disable_relro(Obj_Entry *obj)
5436 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5440 obj_enforce_relro(Obj_Entry *obj)
5443 return (obj_remap_relro(obj, PROT_READ));
5447 map_stacks_exec(RtldLockState *lockstate)
5449 void (*thr_map_stacks_exec)(void);
5451 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5453 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5454 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5455 if (thr_map_stacks_exec != NULL) {
5456 stack_prot |= PROT_EXEC;
5457 thr_map_stacks_exec();
5462 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5466 void (*distrib)(size_t, void *, size_t, size_t);
5468 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5469 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5470 if (distrib == NULL)
5472 STAILQ_FOREACH(elm, list, link) {
5474 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5476 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5478 obj->static_tls_copied = true;
5483 symlook_init(SymLook *dst, const char *name)
5486 bzero(dst, sizeof(*dst));
5488 dst->hash = elf_hash(name);
5489 dst->hash_gnu = gnu_hash(name);
5493 symlook_init_from_req(SymLook *dst, const SymLook *src)
5496 dst->name = src->name;
5497 dst->hash = src->hash;
5498 dst->hash_gnu = src->hash_gnu;
5499 dst->ventry = src->ventry;
5500 dst->flags = src->flags;
5501 dst->defobj_out = NULL;
5502 dst->sym_out = NULL;
5503 dst->lockstate = src->lockstate;
5507 open_binary_fd(const char *argv0, bool search_in_path,
5508 const char **binpath_res)
5510 char *binpath, *pathenv, *pe, *res1;
5516 if (search_in_path && strchr(argv0, '/') == NULL) {
5517 binpath = xmalloc(PATH_MAX);
5518 pathenv = getenv("PATH");
5519 if (pathenv == NULL) {
5520 _rtld_error("-p and no PATH environment variable");
5523 pathenv = strdup(pathenv);
5524 if (pathenv == NULL) {
5525 _rtld_error("Cannot allocate memory");
5530 while ((pe = strsep(&pathenv, ":")) != NULL) {
5531 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
5533 if (binpath[0] != '\0' &&
5534 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
5536 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
5538 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5539 if (fd != -1 || errno != ENOENT) {
5546 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5551 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5554 if (res != NULL && res[0] != '/') {
5555 res1 = xmalloc(PATH_MAX);
5556 if (realpath(res, res1) != NULL) {
5558 free(__DECONST(char *, res));
5569 * Parse a set of command-line arguments.
5572 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
5578 int arglen, fd, i, j, mib[2];
5580 bool seen_b, seen_f;
5582 dbg("Parsing command-line arguments");
5585 seen_b = seen_f = false;
5587 for (i = 1; i < argc; i++ ) {
5589 dbg("argv[%d]: '%s'", i, arg);
5592 * rtld arguments end with an explicit "--" or with the first
5593 * non-prefixed argument.
5595 if (strcmp(arg, "--") == 0) {
5603 * All other arguments are single-character options that can
5604 * be combined, so we need to search through `arg` for them.
5606 arglen = strlen(arg);
5607 for (j = 1; j < arglen; j++) {
5610 print_usage(argv[0]);
5612 } else if (opt == 'b') {
5614 _rtld_error("Both -b and -f specified");
5621 } else if (opt == 'f') {
5623 _rtld_error("Both -b and -f specified");
5628 * -f XX can be used to specify a
5629 * descriptor for the binary named at
5630 * the command line (i.e., the later
5631 * argument will specify the process
5632 * name but the descriptor is what
5633 * will actually be executed).
5635 * -f must be the last option in, e.g., -abcf.
5637 if (j != arglen - 1) {
5638 _rtld_error("Invalid options: %s", arg);
5642 fd = parse_integer(argv[i]);
5645 "Invalid file descriptor: '%s'",
5652 } else if (opt == 'p') {
5654 } else if (opt == 'v') {
5657 mib[1] = HW_MACHINE;
5658 sz = sizeof(machine);
5659 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
5661 "FreeBSD ld-elf.so.1 %s\n"
5662 "FreeBSD_version %d\n"
5663 "Default lib path %s\n"
5668 __FreeBSD_version, ld_standard_library_path,
5669 ld_env_prefix, ld_elf_hints_default,
5670 ld_path_libmap_conf);
5673 _rtld_error("Invalid argument: '%s'", arg);
5674 print_usage(argv[0]);
5686 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5689 parse_integer(const char *str)
5691 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5698 for (c = *str; c != '\0'; c = *++str) {
5699 if (c < '0' || c > '9')
5706 /* Make sure we actually parsed something. */
5713 print_usage(const char *argv0)
5717 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n"
5720 " -h Display this help message\n"
5721 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
5722 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5723 " -p Search in PATH for named binary\n"
5724 " -v Display identification information\n"
5725 " -- End of RTLD options\n"
5726 " <binary> Name of process to execute\n"
5727 " <args> Arguments to the executed process\n", argv0);
5731 * Overrides for libc_pic-provided functions.
5735 __getosreldate(void)
5745 oid[1] = KERN_OSRELDATE;
5747 len = sizeof(osrel);
5748 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5749 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5761 void (*__cleanup)(void);
5762 int __isthreaded = 0;
5763 int _thread_autoinit_dummy_decl = 1;
5766 * No unresolved symbols for rtld.
5769 __pthread_cxa_finalize(struct dl_phdr_info *a __unused)
5774 rtld_strerror(int errnum)
5777 if (errnum < 0 || errnum >= sys_nerr)
5778 return ("Unknown error");
5779 return (sys_errlist[errnum]);
5783 * No ifunc relocations.
5786 memset(void *dest, int c, size_t len)
5790 for (i = 0; i < len; i++)
5791 ((char *)dest)[i] = c;
5796 bzero(void *dest, size_t len)
5800 for (i = 0; i < len; i++)
5801 ((char *)dest)[i] = 0;
5806 malloc(size_t nbytes)
5809 return (__crt_malloc(nbytes));
5813 calloc(size_t num, size_t size)
5816 return (__crt_calloc(num, size));
5827 realloc(void *cp, size_t nbytes)
5830 return (__crt_realloc(cp, nbytes));
5833 extern int _rtld_version__FreeBSD_version __exported;
5834 int _rtld_version__FreeBSD_version = __FreeBSD_version;
5836 extern char _rtld_version_laddr_offset __exported;
5837 char _rtld_version_laddr_offset;