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;
1328 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1335 obj->traced = false;
1337 if (plttype == DT_RELA) {
1338 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1340 obj->pltrelasize = obj->pltrelsize;
1341 obj->pltrelsize = 0;
1344 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1345 if (obj->valid_hash_sysv)
1346 obj->dynsymcount = obj->nchains;
1347 else if (obj->valid_hash_gnu) {
1348 obj->dynsymcount = 0;
1349 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1350 if (obj->buckets_gnu[bkt] == 0)
1352 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1355 while ((*hashval++ & 1u) == 0);
1357 obj->dynsymcount += obj->symndx_gnu;
1360 if (obj->linkmap.l_refname != NULL)
1361 obj->linkmap.l_refname = obj->strtab + (unsigned long)obj->
1366 obj_resolve_origin(Obj_Entry *obj)
1369 if (obj->origin_path != NULL)
1371 obj->origin_path = xmalloc(PATH_MAX);
1372 return (rtld_dirname_abs(obj->path, obj->origin_path) != -1);
1376 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1377 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1380 if (obj->z_origin && !obj_resolve_origin(obj))
1383 if (dyn_runpath != NULL) {
1384 obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val;
1385 obj->runpath = origin_subst(obj, obj->runpath);
1386 } else if (dyn_rpath != NULL) {
1387 obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val;
1388 obj->rpath = origin_subst(obj, obj->rpath);
1390 if (dyn_soname != NULL)
1391 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1396 digest_dynamic(Obj_Entry *obj, int early)
1398 const Elf_Dyn *dyn_rpath;
1399 const Elf_Dyn *dyn_soname;
1400 const Elf_Dyn *dyn_runpath;
1402 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1403 return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath));
1407 * Process a shared object's program header. This is used only for the
1408 * main program, when the kernel has already loaded the main program
1409 * into memory before calling the dynamic linker. It creates and
1410 * returns an Obj_Entry structure.
1413 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1416 const Elf_Phdr *phlimit = phdr + phnum;
1418 Elf_Addr note_start, note_end;
1422 for (ph = phdr; ph < phlimit; ph++) {
1423 if (ph->p_type != PT_PHDR)
1427 obj->phsize = ph->p_memsz;
1428 obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr;
1432 obj->stack_flags = PF_X | PF_R | PF_W;
1434 for (ph = phdr; ph < phlimit; ph++) {
1435 switch (ph->p_type) {
1438 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1442 if (nsegs == 0) { /* First load segment */
1443 obj->vaddrbase = trunc_page(ph->p_vaddr);
1444 obj->mapbase = obj->vaddrbase + obj->relocbase;
1445 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1447 } else { /* Last load segment */
1448 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1455 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1460 obj->tlssize = ph->p_memsz;
1461 obj->tlsalign = ph->p_align;
1462 obj->tlsinitsize = ph->p_filesz;
1463 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1464 obj->tlspoffset = ph->p_offset;
1468 obj->stack_flags = ph->p_flags;
1472 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1473 obj->relro_size = round_page(ph->p_memsz);
1477 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1478 note_end = note_start + ph->p_filesz;
1479 digest_notes(obj, note_start, note_end);
1484 _rtld_error("%s: too few PT_LOAD segments", path);
1493 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1495 const Elf_Note *note;
1496 const char *note_name;
1499 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1500 note = (const Elf_Note *)((const char *)(note + 1) +
1501 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1502 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1503 if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) ||
1504 note->n_descsz != sizeof(int32_t))
1506 if (note->n_type != NT_FREEBSD_ABI_TAG &&
1507 note->n_type != NT_FREEBSD_FEATURE_CTL &&
1508 note->n_type != NT_FREEBSD_NOINIT_TAG)
1510 note_name = (const char *)(note + 1);
1511 if (strncmp(NOTE_FREEBSD_VENDOR, note_name,
1512 sizeof(NOTE_FREEBSD_VENDOR)) != 0)
1514 switch (note->n_type) {
1515 case NT_FREEBSD_ABI_TAG:
1516 /* FreeBSD osrel note */
1517 p = (uintptr_t)(note + 1);
1518 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1519 obj->osrel = *(const int32_t *)(p);
1520 dbg("note osrel %d", obj->osrel);
1522 case NT_FREEBSD_FEATURE_CTL:
1523 /* FreeBSD ABI feature control note */
1524 p = (uintptr_t)(note + 1);
1525 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1526 obj->fctl0 = *(const uint32_t *)(p);
1527 dbg("note fctl0 %#x", obj->fctl0);
1529 case NT_FREEBSD_NOINIT_TAG:
1530 /* FreeBSD 'crt does not call init' note */
1531 obj->crt_no_init = true;
1532 dbg("note crt_no_init");
1539 dlcheck(void *handle)
1543 TAILQ_FOREACH(obj, &obj_list, next) {
1544 if (obj == (Obj_Entry *) handle)
1548 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1549 _rtld_error("Invalid shared object handle %p", handle);
1556 * If the given object is already in the donelist, return true. Otherwise
1557 * add the object to the list and return false.
1560 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1564 for (i = 0; i < dlp->num_used; i++)
1565 if (dlp->objs[i] == obj)
1568 * Our donelist allocation should always be sufficient. But if
1569 * our threads locking isn't working properly, more shared objects
1570 * could have been loaded since we allocated the list. That should
1571 * never happen, but we'll handle it properly just in case it does.
1573 if (dlp->num_used < dlp->num_alloc)
1574 dlp->objs[dlp->num_used++] = obj;
1579 * Hash function for symbol table lookup. Don't even think about changing
1580 * this. It is specified by the System V ABI.
1583 elf_hash(const char *name)
1585 const unsigned char *p = (const unsigned char *) name;
1586 unsigned long h = 0;
1589 while (*p != '\0') {
1590 h = (h << 4) + *p++;
1591 if ((g = h & 0xf0000000) != 0)
1599 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1600 * unsigned in case it's implemented with a wider type.
1603 gnu_hash(const char *s)
1609 for (c = *s; c != '\0'; c = *++s)
1611 return (h & 0xffffffff);
1616 * Find the library with the given name, and return its full pathname.
1617 * The returned string is dynamically allocated. Generates an error
1618 * message and returns NULL if the library cannot be found.
1620 * If the second argument is non-NULL, then it refers to an already-
1621 * loaded shared object, whose library search path will be searched.
1623 * If a library is successfully located via LD_LIBRARY_PATH_FDS, its
1624 * descriptor (which is close-on-exec) will be passed out via the third
1627 * The search order is:
1628 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1629 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1631 * DT_RUNPATH in the referencing file
1632 * ldconfig hints (if -z nodefaultlib, filter out default library directories
1634 * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1636 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1639 find_library(const char *xname, const Obj_Entry *refobj, int *fdp)
1641 char *pathname, *refobj_path;
1643 bool nodeflib, objgiven;
1645 objgiven = refobj != NULL;
1647 if (libmap_disable || !objgiven ||
1648 (name = lm_find(refobj->path, xname)) == NULL)
1651 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
1652 if (name[0] != '/' && !trust) {
1653 _rtld_error("Absolute pathname required "
1654 "for shared object \"%s\"", name);
1657 return (origin_subst(__DECONST(Obj_Entry *, refobj),
1658 __DECONST(char *, name)));
1661 dbg(" Searching for \"%s\"", name);
1662 refobj_path = objgiven ? refobj->path : NULL;
1665 * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall
1666 * back to pre-conforming behaviour if user requested so with
1667 * LD_LIBRARY_PATH_RPATH environment variable and ignore -z
1670 if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) {
1671 pathname = search_library_path(name, ld_library_path,
1673 if (pathname != NULL)
1675 if (refobj != NULL) {
1676 pathname = search_library_path(name, refobj->rpath,
1678 if (pathname != NULL)
1681 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1682 if (pathname != NULL)
1684 pathname = search_library_path(name, gethints(false),
1686 if (pathname != NULL)
1688 pathname = search_library_path(name, ld_standard_library_path,
1690 if (pathname != NULL)
1693 nodeflib = objgiven ? refobj->z_nodeflib : false;
1695 pathname = search_library_path(name, refobj->rpath,
1697 if (pathname != NULL)
1700 if (objgiven && refobj->runpath == NULL && refobj != obj_main) {
1701 pathname = search_library_path(name, obj_main->rpath,
1703 if (pathname != NULL)
1706 pathname = search_library_path(name, ld_library_path,
1708 if (pathname != NULL)
1711 pathname = search_library_path(name, refobj->runpath,
1713 if (pathname != NULL)
1716 pathname = search_library_pathfds(name, ld_library_dirs, fdp);
1717 if (pathname != NULL)
1719 pathname = search_library_path(name, gethints(nodeflib),
1721 if (pathname != NULL)
1723 if (objgiven && !nodeflib) {
1724 pathname = search_library_path(name,
1725 ld_standard_library_path, refobj_path, fdp);
1726 if (pathname != NULL)
1731 if (objgiven && refobj->path != NULL) {
1732 _rtld_error("Shared object \"%s\" not found, "
1733 "required by \"%s\"", name, basename(refobj->path));
1735 _rtld_error("Shared object \"%s\" not found", name);
1741 * Given a symbol number in a referencing object, find the corresponding
1742 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1743 * no definition was found. Returns a pointer to the Obj_Entry of the
1744 * defining object via the reference parameter DEFOBJ_OUT.
1747 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1748 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1749 RtldLockState *lockstate)
1753 const Obj_Entry *defobj;
1754 const Ver_Entry *ve;
1760 * If we have already found this symbol, get the information from
1763 if (symnum >= refobj->dynsymcount)
1764 return NULL; /* Bad object */
1765 if (cache != NULL && cache[symnum].sym != NULL) {
1766 *defobj_out = cache[symnum].obj;
1767 return cache[symnum].sym;
1770 ref = refobj->symtab + symnum;
1771 name = refobj->strtab + ref->st_name;
1777 * We don't have to do a full scale lookup if the symbol is local.
1778 * We know it will bind to the instance in this load module; to
1779 * which we already have a pointer (ie ref). By not doing a lookup,
1780 * we not only improve performance, but it also avoids unresolvable
1781 * symbols when local symbols are not in the hash table. This has
1782 * been seen with the ia64 toolchain.
1784 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1785 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1786 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1789 symlook_init(&req, name);
1791 ve = req.ventry = fetch_ventry(refobj, symnum);
1792 req.lockstate = lockstate;
1793 res = symlook_default(&req, refobj);
1796 defobj = req.defobj_out;
1804 * If we found no definition and the reference is weak, treat the
1805 * symbol as having the value zero.
1807 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1813 *defobj_out = defobj;
1814 /* Record the information in the cache to avoid subsequent lookups. */
1815 if (cache != NULL) {
1816 cache[symnum].sym = def;
1817 cache[symnum].obj = defobj;
1820 if (refobj != &obj_rtld)
1821 _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name,
1822 ve != NULL ? "@" : "", ve != NULL ? ve->name : "");
1828 * Return the search path from the ldconfig hints file, reading it if
1829 * necessary. If nostdlib is true, then the default search paths are
1830 * not added to result.
1832 * Returns NULL if there are problems with the hints file,
1833 * or if the search path there is empty.
1836 gethints(bool nostdlib)
1838 static char *filtered_path;
1839 static const char *hints;
1840 static struct elfhints_hdr hdr;
1841 struct fill_search_info_args sargs, hargs;
1842 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1843 struct dl_serpath *SLPpath, *hintpath;
1845 struct stat hint_stat;
1846 unsigned int SLPndx, hintndx, fndx, fcount;
1852 /* First call, read the hints file */
1853 if (hints == NULL) {
1854 /* Keep from trying again in case the hints file is bad. */
1857 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1861 * Check of hdr.dirlistlen value against type limit
1862 * intends to pacify static analyzers. Further
1863 * paranoia leads to checks that dirlist is fully
1864 * contained in the file range.
1866 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1867 hdr.magic != ELFHINTS_MAGIC ||
1868 hdr.version != 1 || hdr.dirlistlen > UINT_MAX / 2 ||
1869 fstat(fd, &hint_stat) == -1) {
1876 if (dl + hdr.dirlist < dl)
1879 if (dl + hdr.dirlistlen < dl)
1881 dl += hdr.dirlistlen;
1882 if (dl > hint_stat.st_size)
1884 p = xmalloc(hdr.dirlistlen + 1);
1885 if (pread(fd, p, hdr.dirlistlen + 1,
1886 hdr.strtab + hdr.dirlist) != (ssize_t)hdr.dirlistlen + 1 ||
1887 p[hdr.dirlistlen] != '\0') {
1896 * If caller agreed to receive list which includes the default
1897 * paths, we are done. Otherwise, if we still did not
1898 * calculated filtered result, do it now.
1901 return (hints[0] != '\0' ? hints : NULL);
1902 if (filtered_path != NULL)
1906 * Obtain the list of all configured search paths, and the
1907 * list of the default paths.
1909 * First estimate the size of the results.
1911 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1913 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1916 sargs.request = RTLD_DI_SERINFOSIZE;
1917 sargs.serinfo = &smeta;
1918 hargs.request = RTLD_DI_SERINFOSIZE;
1919 hargs.serinfo = &hmeta;
1921 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1923 path_enumerate(hints, fill_search_info, NULL, &hargs);
1925 SLPinfo = xmalloc(smeta.dls_size);
1926 hintinfo = xmalloc(hmeta.dls_size);
1929 * Next fetch both sets of paths.
1931 sargs.request = RTLD_DI_SERINFO;
1932 sargs.serinfo = SLPinfo;
1933 sargs.serpath = &SLPinfo->dls_serpath[0];
1934 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1936 hargs.request = RTLD_DI_SERINFO;
1937 hargs.serinfo = hintinfo;
1938 hargs.serpath = &hintinfo->dls_serpath[0];
1939 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1941 path_enumerate(ld_standard_library_path, fill_search_info, NULL,
1943 path_enumerate(hints, fill_search_info, NULL, &hargs);
1946 * Now calculate the difference between two sets, by excluding
1947 * standard paths from the full set.
1951 filtered_path = xmalloc(hdr.dirlistlen + 1);
1952 hintpath = &hintinfo->dls_serpath[0];
1953 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1955 SLPpath = &SLPinfo->dls_serpath[0];
1957 * Check each standard path against current.
1959 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1960 /* matched, skip the path */
1961 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1969 * Not matched against any standard path, add the path
1970 * to result. Separate consequtive paths with ':'.
1973 filtered_path[fndx] = ':';
1977 flen = strlen(hintpath->dls_name);
1978 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1981 filtered_path[fndx] = '\0';
1987 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1991 init_dag(Obj_Entry *root)
1993 const Needed_Entry *needed;
1994 const Objlist_Entry *elm;
1997 if (root->dag_inited)
1999 donelist_init(&donelist);
2001 /* Root object belongs to own DAG. */
2002 objlist_push_tail(&root->dldags, root);
2003 objlist_push_tail(&root->dagmembers, root);
2004 donelist_check(&donelist, root);
2007 * Add dependencies of root object to DAG in breadth order
2008 * by exploiting the fact that each new object get added
2009 * to the tail of the dagmembers list.
2011 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2012 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
2013 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
2015 objlist_push_tail(&needed->obj->dldags, root);
2016 objlist_push_tail(&root->dagmembers, needed->obj);
2019 root->dag_inited = true;
2023 init_marker(Obj_Entry *marker)
2026 bzero(marker, sizeof(*marker));
2027 marker->marker = true;
2031 globallist_curr(const Obj_Entry *obj)
2038 return (__DECONST(Obj_Entry *, obj));
2039 obj = TAILQ_PREV(obj, obj_entry_q, next);
2044 globallist_next(const Obj_Entry *obj)
2048 obj = TAILQ_NEXT(obj, next);
2052 return (__DECONST(Obj_Entry *, obj));
2056 /* Prevent the object from being unmapped while the bind lock is dropped. */
2058 hold_object(Obj_Entry *obj)
2065 unhold_object(Obj_Entry *obj)
2068 assert(obj->holdcount > 0);
2069 if (--obj->holdcount == 0 && obj->unholdfree)
2070 release_object(obj);
2074 process_z(Obj_Entry *root)
2076 const Objlist_Entry *elm;
2080 * Walk over object DAG and process every dependent object
2081 * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
2082 * to grow their own DAG.
2084 * For DF_1_GLOBAL, DAG is required for symbol lookups in
2085 * symlook_global() to work.
2087 * For DF_1_NODELETE, the DAG should have its reference upped.
2089 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2093 if (obj->z_nodelete && !obj->ref_nodel) {
2094 dbg("obj %s -z nodelete", obj->path);
2097 obj->ref_nodel = true;
2099 if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
2100 dbg("obj %s -z global", obj->path);
2101 objlist_push_tail(&list_global, obj);
2107 * Initialize the dynamic linker. The argument is the address at which
2108 * the dynamic linker has been mapped into memory. The primary task of
2109 * this function is to relocate the dynamic linker.
2112 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
2114 Obj_Entry objtmp; /* Temporary rtld object */
2115 const Elf_Ehdr *ehdr;
2116 const Elf_Dyn *dyn_rpath;
2117 const Elf_Dyn *dyn_soname;
2118 const Elf_Dyn *dyn_runpath;
2120 #ifdef RTLD_INIT_PAGESIZES_EARLY
2121 /* The page size is required by the dynamic memory allocator. */
2122 init_pagesizes(aux_info);
2126 * Conjure up an Obj_Entry structure for the dynamic linker.
2128 * The "path" member can't be initialized yet because string constants
2129 * cannot yet be accessed. Below we will set it correctly.
2131 memset(&objtmp, 0, sizeof(objtmp));
2134 objtmp.mapbase = mapbase;
2136 objtmp.relocbase = mapbase;
2139 objtmp.dynamic = rtld_dynamic(&objtmp);
2140 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
2141 assert(objtmp.needed == NULL);
2142 #if !defined(__mips__)
2143 /* MIPS has a bogus DT_TEXTREL. */
2144 assert(!objtmp.textrel);
2147 * Temporarily put the dynamic linker entry into the object list, so
2148 * that symbols can be found.
2150 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
2152 ehdr = (Elf_Ehdr *)mapbase;
2153 objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff);
2154 objtmp.phsize = ehdr->e_phnum * sizeof(objtmp.phdr[0]);
2156 /* Initialize the object list. */
2157 TAILQ_INIT(&obj_list);
2159 /* Now that non-local variables can be accesses, copy out obj_rtld. */
2160 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
2162 #ifndef RTLD_INIT_PAGESIZES_EARLY
2163 /* The page size is required by the dynamic memory allocator. */
2164 init_pagesizes(aux_info);
2167 if (aux_info[AT_OSRELDATE] != NULL)
2168 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
2170 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
2172 /* Replace the path with a dynamically allocated copy. */
2173 obj_rtld.path = xstrdup(ld_path_rtld);
2175 r_debug.r_brk = r_debug_state;
2176 r_debug.r_state = RT_CONSISTENT;
2180 * Retrieve the array of supported page sizes. The kernel provides the page
2181 * sizes in increasing order.
2184 init_pagesizes(Elf_Auxinfo **aux_info)
2186 static size_t psa[MAXPAGESIZES];
2190 if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] !=
2192 size = aux_info[AT_PAGESIZESLEN]->a_un.a_val;
2193 pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr;
2196 if (sysctlnametomib("hw.pagesizes", mib, &len) == 0)
2199 /* As a fallback, retrieve the base page size. */
2200 size = sizeof(psa[0]);
2201 if (aux_info[AT_PAGESZ] != NULL) {
2202 psa[0] = aux_info[AT_PAGESZ]->a_un.a_val;
2206 mib[1] = HW_PAGESIZE;
2210 if (sysctl(mib, len, psa, &size, NULL, 0) == -1) {
2211 _rtld_error("sysctl for hw.pagesize(s) failed");
2217 npagesizes = size / sizeof(pagesizes[0]);
2218 /* Discard any invalid entries at the end of the array. */
2219 while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0)
2224 * Add the init functions from a needed object list (and its recursive
2225 * needed objects) to "list". This is not used directly; it is a helper
2226 * function for initlist_add_objects(). The write lock must be held
2227 * when this function is called.
2230 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
2232 /* Recursively process the successor needed objects. */
2233 if (needed->next != NULL)
2234 initlist_add_neededs(needed->next, list);
2236 /* Process the current needed object. */
2237 if (needed->obj != NULL)
2238 initlist_add_objects(needed->obj, needed->obj, list);
2242 * Scan all of the DAGs rooted in the range of objects from "obj" to
2243 * "tail" and add their init functions to "list". This recurses over
2244 * the DAGs and ensure the proper init ordering such that each object's
2245 * needed libraries are initialized before the object itself. At the
2246 * same time, this function adds the objects to the global finalization
2247 * list "list_fini" in the opposite order. The write lock must be
2248 * held when this function is called.
2251 initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list)
2255 if (obj->init_scanned || obj->init_done)
2257 obj->init_scanned = true;
2259 /* Recursively process the successor objects. */
2260 nobj = globallist_next(obj);
2261 if (nobj != NULL && obj != tail)
2262 initlist_add_objects(nobj, tail, list);
2264 /* Recursively process the needed objects. */
2265 if (obj->needed != NULL)
2266 initlist_add_neededs(obj->needed, list);
2267 if (obj->needed_filtees != NULL)
2268 initlist_add_neededs(obj->needed_filtees, list);
2269 if (obj->needed_aux_filtees != NULL)
2270 initlist_add_neededs(obj->needed_aux_filtees, list);
2272 /* Add the object to the init list. */
2273 objlist_push_tail(list, obj);
2275 /* Add the object to the global fini list in the reverse order. */
2276 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
2277 && !obj->on_fini_list) {
2278 objlist_push_head(&list_fini, obj);
2279 obj->on_fini_list = true;
2284 #define FPTR_TARGET(f) ((Elf_Addr) (f))
2288 free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate)
2290 Needed_Entry *needed, *needed1;
2292 for (needed = n; needed != NULL; needed = needed->next) {
2293 if (needed->obj != NULL) {
2294 dlclose_locked(needed->obj, lockstate);
2298 for (needed = n; needed != NULL; needed = needed1) {
2299 needed1 = needed->next;
2305 unload_filtees(Obj_Entry *obj, RtldLockState *lockstate)
2308 free_needed_filtees(obj->needed_filtees, lockstate);
2309 obj->needed_filtees = NULL;
2310 free_needed_filtees(obj->needed_aux_filtees, lockstate);
2311 obj->needed_aux_filtees = NULL;
2312 obj->filtees_loaded = false;
2316 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
2317 RtldLockState *lockstate)
2320 for (; needed != NULL; needed = needed->next) {
2321 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
2322 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
2323 RTLD_LOCAL, lockstate);
2328 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2331 lock_restart_for_upgrade(lockstate);
2332 if (!obj->filtees_loaded) {
2333 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2334 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2335 obj->filtees_loaded = true;
2340 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2344 for (; needed != NULL; needed = needed->next) {
2345 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2346 flags & ~RTLD_LO_NOLOAD);
2347 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2354 * Given a shared object, traverse its list of needed objects, and load
2355 * each of them. Returns 0 on success. Generates an error message and
2356 * returns -1 on failure.
2359 load_needed_objects(Obj_Entry *first, int flags)
2363 for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
2366 if (process_needed(obj, obj->needed, flags) == -1)
2373 load_preload_objects(void)
2375 char *p = ld_preload;
2377 static const char delim[] = " \t:;";
2382 p += strspn(p, delim);
2383 while (*p != '\0') {
2384 size_t len = strcspn(p, delim);
2389 obj = load_object(p, -1, NULL, 0);
2391 return -1; /* XXX - cleanup */
2392 obj->z_interpose = true;
2395 p += strspn(p, delim);
2397 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2402 printable_path(const char *path)
2405 return (path == NULL ? "<unknown>" : path);
2409 * Load a shared object into memory, if it is not already loaded. The
2410 * object may be specified by name or by user-supplied file descriptor
2411 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2414 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2418 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2427 TAILQ_FOREACH(obj, &obj_list, next) {
2428 if (obj->marker || obj->doomed)
2430 if (object_match_name(obj, name))
2434 path = find_library(name, refobj, &fd);
2442 * search_library_pathfds() opens a fresh file descriptor for the
2443 * library, so there is no need to dup().
2445 } else if (fd_u == -1) {
2447 * If we didn't find a match by pathname, or the name is not
2448 * supplied, open the file and check again by device and inode.
2449 * This avoids false mismatches caused by multiple links or ".."
2452 * To avoid a race, we open the file and use fstat() rather than
2455 if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) {
2456 _rtld_error("Cannot open \"%s\"", path);
2461 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2463 _rtld_error("Cannot dup fd");
2468 if (fstat(fd, &sb) == -1) {
2469 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2474 TAILQ_FOREACH(obj, &obj_list, next) {
2475 if (obj->marker || obj->doomed)
2477 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2480 if (obj != NULL && name != NULL) {
2481 object_add_name(obj, name);
2486 if (flags & RTLD_LO_NOLOAD) {
2492 /* First use of this object, so we must map it in */
2493 obj = do_load_object(fd, name, path, &sb, flags);
2502 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2509 * but first, make sure that environment variables haven't been
2510 * used to circumvent the noexec flag on a filesystem.
2512 if (dangerous_ld_env) {
2513 if (fstatfs(fd, &fs) != 0) {
2514 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2517 if (fs.f_flags & MNT_NOEXEC) {
2518 _rtld_error("Cannot execute objects on %s", fs.f_mntonname);
2522 dbg("loading \"%s\"", printable_path(path));
2523 obj = map_object(fd, printable_path(path), sbp);
2528 * If DT_SONAME is present in the object, digest_dynamic2 already
2529 * added it to the object names.
2532 object_add_name(obj, name);
2534 if (!digest_dynamic(obj, 0))
2536 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2537 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2538 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2540 dbg("refusing to load non-loadable \"%s\"", obj->path);
2541 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2545 obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0;
2546 TAILQ_INSERT_TAIL(&obj_list, obj, next);
2549 linkmap_add(obj); /* for GDB & dlinfo() */
2550 max_stack_flags |= obj->stack_flags;
2552 dbg(" %p .. %p: %s", obj->mapbase,
2553 obj->mapbase + obj->mapsize - 1, obj->path);
2555 dbg(" WARNING: %s has impure text", obj->path);
2556 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2562 munmap(obj->mapbase, obj->mapsize);
2568 obj_from_addr(const void *addr)
2572 TAILQ_FOREACH(obj, &obj_list, next) {
2575 if (addr < (void *) obj->mapbase)
2577 if (addr < (void *)(obj->mapbase + obj->mapsize))
2586 Elf_Addr *preinit_addr;
2589 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2590 if (preinit_addr == NULL)
2593 for (index = 0; index < obj_main->preinit_array_num; index++) {
2594 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2595 dbg("calling preinit function for %s at %p", obj_main->path,
2596 (void *)preinit_addr[index]);
2597 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2598 0, 0, obj_main->path);
2599 call_init_pointer(obj_main, preinit_addr[index]);
2605 * Call the finalization functions for each of the objects in "list"
2606 * belonging to the DAG of "root" and referenced once. If NULL "root"
2607 * is specified, every finalization function will be called regardless
2608 * of the reference count and the list elements won't be freed. All of
2609 * the objects are expected to have non-NULL fini functions.
2612 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2616 Elf_Addr *fini_addr;
2619 assert(root == NULL || root->refcount == 1);
2622 root->doomed = true;
2625 * Preserve the current error message since a fini function might
2626 * call into the dynamic linker and overwrite it.
2628 saved_msg = errmsg_save();
2630 STAILQ_FOREACH(elm, list, link) {
2631 if (root != NULL && (elm->obj->refcount != 1 ||
2632 objlist_find(&root->dagmembers, elm->obj) == NULL))
2634 /* Remove object from fini list to prevent recursive invocation. */
2635 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2636 /* Ensure that new references cannot be acquired. */
2637 elm->obj->doomed = true;
2639 hold_object(elm->obj);
2640 lock_release(rtld_bind_lock, lockstate);
2642 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined.
2643 * When this happens, DT_FINI_ARRAY is processed first.
2645 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2646 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2647 for (index = elm->obj->fini_array_num - 1; index >= 0;
2649 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2650 dbg("calling fini function for %s at %p",
2651 elm->obj->path, (void *)fini_addr[index]);
2652 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2653 (void *)fini_addr[index], 0, 0, elm->obj->path);
2654 call_initfini_pointer(elm->obj, fini_addr[index]);
2658 if (elm->obj->fini != (Elf_Addr)NULL) {
2659 dbg("calling fini function for %s at %p", elm->obj->path,
2660 (void *)elm->obj->fini);
2661 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2662 0, 0, elm->obj->path);
2663 call_initfini_pointer(elm->obj, elm->obj->fini);
2665 wlock_acquire(rtld_bind_lock, lockstate);
2666 unhold_object(elm->obj);
2667 /* No need to free anything if process is going down. */
2671 * We must restart the list traversal after every fini call
2672 * because a dlclose() call from the fini function or from
2673 * another thread might have modified the reference counts.
2677 } while (elm != NULL);
2678 errmsg_restore(saved_msg);
2682 * Call the initialization functions for each of the objects in
2683 * "list". All of the objects are expected to have non-NULL init
2687 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2692 Elf_Addr *init_addr;
2693 void (*reg)(void (*)(void));
2697 * Clean init_scanned flag so that objects can be rechecked and
2698 * possibly initialized earlier if any of vectors called below
2699 * cause the change by using dlopen.
2701 TAILQ_FOREACH(obj, &obj_list, next) {
2704 obj->init_scanned = false;
2708 * Preserve the current error message since an init function might
2709 * call into the dynamic linker and overwrite it.
2711 saved_msg = errmsg_save();
2712 STAILQ_FOREACH(elm, list, link) {
2713 if (elm->obj->init_done) /* Initialized early. */
2716 * Race: other thread might try to use this object before current
2717 * one completes the initialization. Not much can be done here
2718 * without better locking.
2720 elm->obj->init_done = true;
2721 hold_object(elm->obj);
2723 if (elm->obj == obj_main && obj_main->crt_no_init) {
2724 reg = (void (*)(void (*)(void)))get_program_var_addr(
2725 "__libc_atexit", lockstate);
2727 lock_release(rtld_bind_lock, lockstate);
2730 rtld_exit_ptr = rtld_nop_exit;
2734 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined.
2735 * When this happens, DT_INIT is processed first.
2737 if (elm->obj->init != (Elf_Addr)NULL) {
2738 dbg("calling init function for %s at %p", elm->obj->path,
2739 (void *)elm->obj->init);
2740 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2741 0, 0, elm->obj->path);
2742 call_initfini_pointer(elm->obj, elm->obj->init);
2744 init_addr = (Elf_Addr *)elm->obj->init_array;
2745 if (init_addr != NULL) {
2746 for (index = 0; index < elm->obj->init_array_num; index++) {
2747 if (init_addr[index] != 0 && init_addr[index] != 1) {
2748 dbg("calling init function for %s at %p", elm->obj->path,
2749 (void *)init_addr[index]);
2750 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2751 (void *)init_addr[index], 0, 0, elm->obj->path);
2752 call_init_pointer(elm->obj, init_addr[index]);
2756 wlock_acquire(rtld_bind_lock, lockstate);
2757 unhold_object(elm->obj);
2759 errmsg_restore(saved_msg);
2763 objlist_clear(Objlist *list)
2767 while (!STAILQ_EMPTY(list)) {
2768 elm = STAILQ_FIRST(list);
2769 STAILQ_REMOVE_HEAD(list, link);
2774 static Objlist_Entry *
2775 objlist_find(Objlist *list, const Obj_Entry *obj)
2779 STAILQ_FOREACH(elm, list, link)
2780 if (elm->obj == obj)
2786 objlist_init(Objlist *list)
2792 objlist_push_head(Objlist *list, Obj_Entry *obj)
2796 elm = NEW(Objlist_Entry);
2798 STAILQ_INSERT_HEAD(list, elm, link);
2802 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2806 elm = NEW(Objlist_Entry);
2808 STAILQ_INSERT_TAIL(list, elm, link);
2812 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2814 Objlist_Entry *elm, *listelm;
2816 STAILQ_FOREACH(listelm, list, link) {
2817 if (listelm->obj == listobj)
2820 elm = NEW(Objlist_Entry);
2822 if (listelm != NULL)
2823 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2825 STAILQ_INSERT_TAIL(list, elm, link);
2829 objlist_remove(Objlist *list, Obj_Entry *obj)
2833 if ((elm = objlist_find(list, obj)) != NULL) {
2834 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2840 * Relocate dag rooted in the specified object.
2841 * Returns 0 on success, or -1 on failure.
2845 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2846 int flags, RtldLockState *lockstate)
2852 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2853 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2862 * Prepare for, or clean after, relocating an object marked with
2863 * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only
2864 * segments are remapped read-write. After relocations are done, the
2865 * segment's permissions are returned back to the modes specified in
2866 * the phdrs. If any relocation happened, or always for wired
2867 * program, COW is triggered.
2870 reloc_textrel_prot(Obj_Entry *obj, bool before)
2877 for (l = obj->phsize / sizeof(*ph), ph = obj->phdr; l > 0;
2879 if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0)
2881 base = obj->relocbase + trunc_page(ph->p_vaddr);
2882 sz = round_page(ph->p_vaddr + ph->p_filesz) -
2883 trunc_page(ph->p_vaddr);
2884 prot = convert_prot(ph->p_flags) | (before ? PROT_WRITE : 0);
2885 if (mprotect(base, sz, prot) == -1) {
2886 _rtld_error("%s: Cannot write-%sable text segment: %s",
2887 obj->path, before ? "en" : "dis",
2888 rtld_strerror(errno));
2896 * Relocate single object.
2897 * Returns 0 on success, or -1 on failure.
2900 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2901 int flags, RtldLockState *lockstate)
2906 obj->relocated = true;
2908 dbg("relocating \"%s\"", obj->path);
2910 if (obj->symtab == NULL || obj->strtab == NULL ||
2911 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2912 _rtld_error("%s: Shared object has no run-time symbol table",
2917 /* There are relocations to the write-protected text segment. */
2918 if (obj->textrel && reloc_textrel_prot(obj, true) != 0)
2921 /* Process the non-PLT non-IFUNC relocations. */
2922 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2925 /* Re-protected the text segment. */
2926 if (obj->textrel && reloc_textrel_prot(obj, false) != 0)
2929 /* Set the special PLT or GOT entries. */
2932 /* Process the PLT relocations. */
2933 if (reloc_plt(obj, flags, lockstate) == -1)
2935 /* Relocate the jump slots if we are doing immediate binding. */
2936 if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags,
2940 if (!obj->mainprog && obj_enforce_relro(obj) == -1)
2944 * Set up the magic number and version in the Obj_Entry. These
2945 * were checked in the crt1.o from the original ElfKit, so we
2946 * set them for backward compatibility.
2948 obj->magic = RTLD_MAGIC;
2949 obj->version = RTLD_VERSION;
2955 * Relocate newly-loaded shared objects. The argument is a pointer to
2956 * the Obj_Entry for the first such object. All objects from the first
2957 * to the end of the list of objects are relocated. Returns 0 on success,
2961 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2962 int flags, RtldLockState *lockstate)
2967 for (error = 0, obj = first; obj != NULL;
2968 obj = TAILQ_NEXT(obj, next)) {
2971 error = relocate_object(obj, bind_now, rtldobj, flags,
2980 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2981 * referencing STT_GNU_IFUNC symbols is postponed till the other
2982 * relocations are done. The indirect functions specified as
2983 * ifunc are allowed to call other symbols, so we need to have
2984 * objects relocated before asking for resolution from indirects.
2986 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2987 * instead of the usual lazy handling of PLT slots. It is
2988 * consistent with how GNU does it.
2991 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2992 RtldLockState *lockstate)
2995 if (obj->ifuncs_resolved)
2997 obj->ifuncs_resolved = true;
2998 if (!obj->irelative && !obj->irelative_nonplt &&
2999 !((obj->bind_now || bind_now) && obj->gnu_ifunc))
3001 if (obj_disable_relro(obj) == -1 ||
3002 (obj->irelative && reloc_iresolve(obj, lockstate) == -1) ||
3003 (obj->irelative_nonplt && reloc_iresolve_nonplt(obj,
3004 lockstate) == -1) ||
3005 ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
3006 reloc_gnu_ifunc(obj, flags, lockstate) == -1) ||
3007 obj_enforce_relro(obj) == -1)
3013 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
3014 RtldLockState *lockstate)
3019 STAILQ_FOREACH(elm, list, link) {
3023 if (resolve_object_ifunc(obj, bind_now, flags,
3031 * Cleanup procedure. It will be called (by the atexit mechanism) just
3032 * before the process exits.
3037 RtldLockState lockstate;
3039 wlock_acquire(rtld_bind_lock, &lockstate);
3041 objlist_call_fini(&list_fini, NULL, &lockstate);
3042 /* No need to remove the items from the list, since we are exiting. */
3043 if (!libmap_disable)
3045 lock_release(rtld_bind_lock, &lockstate);
3054 * Iterate over a search path, translate each element, and invoke the
3055 * callback on the result.
3058 path_enumerate(const char *path, path_enum_proc callback,
3059 const char *refobj_path, void *arg)
3065 path += strspn(path, ":;");
3066 while (*path != '\0') {
3070 len = strcspn(path, ":;");
3071 trans = lm_findn(refobj_path, path, len);
3073 res = callback(trans, strlen(trans), arg);
3075 res = callback(path, len, arg);
3081 path += strspn(path, ":;");
3087 struct try_library_args {
3096 try_library_path(const char *dir, size_t dirlen, void *param)
3098 struct try_library_args *arg;
3102 if (*dir == '/' || trust) {
3105 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
3108 pathname = arg->buffer;
3109 strncpy(pathname, dir, dirlen);
3110 pathname[dirlen] = '/';
3111 strcpy(pathname + dirlen + 1, arg->name);
3113 dbg(" Trying \"%s\"", pathname);
3114 fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY);
3116 dbg(" Opened \"%s\", fd %d", pathname, fd);
3117 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
3118 strcpy(pathname, arg->buffer);
3122 dbg(" Failed to open \"%s\": %s",
3123 pathname, rtld_strerror(errno));
3130 search_library_path(const char *name, const char *path,
3131 const char *refobj_path, int *fdp)
3134 struct try_library_args arg;
3140 arg.namelen = strlen(name);
3141 arg.buffer = xmalloc(PATH_MAX);
3142 arg.buflen = PATH_MAX;
3145 p = path_enumerate(path, try_library_path, refobj_path, &arg);
3155 * Finds the library with the given name using the directory descriptors
3156 * listed in the LD_LIBRARY_PATH_FDS environment variable.
3158 * Returns a freshly-opened close-on-exec file descriptor for the library,
3159 * or -1 if the library cannot be found.
3162 search_library_pathfds(const char *name, const char *path, int *fdp)
3164 char *envcopy, *fdstr, *found, *last_token;
3168 dbg("%s('%s', '%s', fdp)", __func__, name, path);
3170 /* Don't load from user-specified libdirs into setuid binaries. */
3174 /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */
3178 /* LD_LIBRARY_PATH_FDS only works with relative paths. */
3179 if (name[0] == '/') {
3180 dbg("Absolute path (%s) passed to %s", name, __func__);
3185 * Use strtok_r() to walk the FD:FD:FD list. This requires a local
3186 * copy of the path, as strtok_r rewrites separator tokens
3190 envcopy = xstrdup(path);
3191 for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL;
3192 fdstr = strtok_r(NULL, ":", &last_token)) {
3193 dirfd = parse_integer(fdstr);
3195 _rtld_error("failed to parse directory FD: '%s'",
3199 fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY);
3202 len = strlen(fdstr) + strlen(name) + 3;
3203 found = xmalloc(len);
3204 if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) {
3205 _rtld_error("error generating '%d/%s'",
3209 dbg("open('%s') => %d", found, fd);
3220 dlclose(void *handle)
3222 RtldLockState lockstate;
3225 wlock_acquire(rtld_bind_lock, &lockstate);
3226 error = dlclose_locked(handle, &lockstate);
3227 lock_release(rtld_bind_lock, &lockstate);
3232 dlclose_locked(void *handle, RtldLockState *lockstate)
3236 root = dlcheck(handle);
3239 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
3242 /* Unreference the object and its dependencies. */
3243 root->dl_refcount--;
3245 if (root->refcount == 1) {
3247 * The object will be no longer referenced, so we must unload it.
3248 * First, call the fini functions.
3250 objlist_call_fini(&list_fini, root, lockstate);
3254 /* Finish cleaning up the newly-unreferenced objects. */
3255 GDB_STATE(RT_DELETE,&root->linkmap);
3256 unload_object(root, lockstate);
3257 GDB_STATE(RT_CONSISTENT,NULL);
3261 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
3268 char *msg = error_message;
3269 error_message = NULL;
3274 * This function is deprecated and has no effect.
3277 dllockinit(void *context,
3278 void *(*_lock_create)(void *context) __unused,
3279 void (*_rlock_acquire)(void *lock) __unused,
3280 void (*_wlock_acquire)(void *lock) __unused,
3281 void (*_lock_release)(void *lock) __unused,
3282 void (*_lock_destroy)(void *lock) __unused,
3283 void (*context_destroy)(void *context))
3285 static void *cur_context;
3286 static void (*cur_context_destroy)(void *);
3288 /* Just destroy the context from the previous call, if necessary. */
3289 if (cur_context_destroy != NULL)
3290 cur_context_destroy(cur_context);
3291 cur_context = context;
3292 cur_context_destroy = context_destroy;
3296 dlopen(const char *name, int mode)
3299 return (rtld_dlopen(name, -1, mode));
3303 fdlopen(int fd, int mode)
3306 return (rtld_dlopen(NULL, fd, mode));
3310 rtld_dlopen(const char *name, int fd, int mode)
3312 RtldLockState lockstate;
3315 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
3316 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
3317 if (ld_tracing != NULL) {
3318 rlock_acquire(rtld_bind_lock, &lockstate);
3319 if (sigsetjmp(lockstate.env, 0) != 0)
3320 lock_upgrade(rtld_bind_lock, &lockstate);
3321 environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate));
3322 lock_release(rtld_bind_lock, &lockstate);
3324 lo_flags = RTLD_LO_DLOPEN;
3325 if (mode & RTLD_NODELETE)
3326 lo_flags |= RTLD_LO_NODELETE;
3327 if (mode & RTLD_NOLOAD)
3328 lo_flags |= RTLD_LO_NOLOAD;
3329 if (mode & RTLD_DEEPBIND)
3330 lo_flags |= RTLD_LO_DEEPBIND;
3331 if (ld_tracing != NULL)
3332 lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
3334 return (dlopen_object(name, fd, obj_main, lo_flags,
3335 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
3339 dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate)
3344 if (obj->refcount == 0)
3345 unload_object(obj, lockstate);
3349 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
3350 int mode, RtldLockState *lockstate)
3352 Obj_Entry *old_obj_tail;
3355 RtldLockState mlockstate;
3358 objlist_init(&initlist);
3360 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
3361 wlock_acquire(rtld_bind_lock, &mlockstate);
3362 lockstate = &mlockstate;
3364 GDB_STATE(RT_ADD,NULL);
3366 old_obj_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q));
3368 if (name == NULL && fd == -1) {
3372 obj = load_object(name, fd, refobj, lo_flags);
3377 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
3378 objlist_push_tail(&list_global, obj);
3379 if (globallist_next(old_obj_tail) != NULL) {
3380 /* We loaded something new. */
3381 assert(globallist_next(old_obj_tail) == obj);
3382 if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
3383 obj->symbolic = true;
3385 if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 &&
3386 obj->static_tls && !allocate_tls_offset(obj)) {
3387 _rtld_error("%s: No space available "
3388 "for static Thread Local Storage", obj->path);
3392 result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN |
3393 RTLD_LO_EARLY | RTLD_LO_IGNSTLS));
3397 result = rtld_verify_versions(&obj->dagmembers);
3398 if (result != -1 && ld_tracing)
3400 if (result == -1 || relocate_object_dag(obj,
3401 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
3402 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3404 dlopen_cleanup(obj, lockstate);
3406 } else if (lo_flags & RTLD_LO_EARLY) {
3408 * Do not call the init functions for early loaded
3409 * filtees. The image is still not initialized enough
3412 * Our object is found by the global object list and
3413 * will be ordered among all init calls done right
3414 * before transferring control to main.
3417 /* Make list of init functions to call. */
3418 initlist_add_objects(obj, obj, &initlist);
3421 * Process all no_delete or global objects here, given
3422 * them own DAGs to prevent their dependencies from being
3423 * unloaded. This has to be done after we have loaded all
3424 * of the dependencies, so that we do not miss any.
3430 * Bump the reference counts for objects on this DAG. If
3431 * this is the first dlopen() call for the object that was
3432 * already loaded as a dependency, initialize the dag
3438 if ((lo_flags & RTLD_LO_TRACE) != 0)
3441 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
3442 obj->z_nodelete) && !obj->ref_nodel) {
3443 dbg("obj %s nodelete", obj->path);
3445 obj->z_nodelete = obj->ref_nodel = true;
3449 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
3451 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
3453 if ((lo_flags & RTLD_LO_EARLY) == 0) {
3454 map_stacks_exec(lockstate);
3456 distribute_static_tls(&initlist, lockstate);
3459 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
3460 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
3462 objlist_clear(&initlist);
3463 dlopen_cleanup(obj, lockstate);
3464 if (lockstate == &mlockstate)
3465 lock_release(rtld_bind_lock, lockstate);
3469 if (!(lo_flags & RTLD_LO_EARLY)) {
3470 /* Call the init functions. */
3471 objlist_call_init(&initlist, lockstate);
3473 objlist_clear(&initlist);
3474 if (lockstate == &mlockstate)
3475 lock_release(rtld_bind_lock, lockstate);
3478 trace_loaded_objects(obj);
3479 if (lockstate == &mlockstate)
3480 lock_release(rtld_bind_lock, lockstate);
3485 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3489 const Obj_Entry *obj, *defobj;
3492 RtldLockState lockstate;
3499 symlook_init(&req, name);
3501 req.flags = flags | SYMLOOK_IN_PLT;
3502 req.lockstate = &lockstate;
3504 LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name);
3505 rlock_acquire(rtld_bind_lock, &lockstate);
3506 if (sigsetjmp(lockstate.env, 0) != 0)
3507 lock_upgrade(rtld_bind_lock, &lockstate);
3508 if (handle == NULL || handle == RTLD_NEXT ||
3509 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3511 if ((obj = obj_from_addr(retaddr)) == NULL) {
3512 _rtld_error("Cannot determine caller's shared object");
3513 lock_release(rtld_bind_lock, &lockstate);
3514 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3517 if (handle == NULL) { /* Just the caller's shared object. */
3518 res = symlook_obj(&req, obj);
3521 defobj = req.defobj_out;
3523 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3524 handle == RTLD_SELF) { /* ... caller included */
3525 if (handle == RTLD_NEXT)
3526 obj = globallist_next(obj);
3527 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
3530 res = symlook_obj(&req, obj);
3533 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3535 defobj = req.defobj_out;
3536 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3542 * Search the dynamic linker itself, and possibly resolve the
3543 * symbol from there. This is how the application links to
3544 * dynamic linker services such as dlopen.
3546 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3547 res = symlook_obj(&req, &obj_rtld);
3550 defobj = req.defobj_out;
3554 assert(handle == RTLD_DEFAULT);
3555 res = symlook_default(&req, obj);
3557 defobj = req.defobj_out;
3562 if ((obj = dlcheck(handle)) == NULL) {
3563 lock_release(rtld_bind_lock, &lockstate);
3564 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3568 donelist_init(&donelist);
3569 if (obj->mainprog) {
3570 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3571 res = symlook_global(&req, &donelist);
3574 defobj = req.defobj_out;
3577 * Search the dynamic linker itself, and possibly resolve the
3578 * symbol from there. This is how the application links to
3579 * dynamic linker services such as dlopen.
3581 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3582 res = symlook_obj(&req, &obj_rtld);
3585 defobj = req.defobj_out;
3590 /* Search the whole DAG rooted at the given object. */
3591 res = symlook_list(&req, &obj->dagmembers, &donelist);
3594 defobj = req.defobj_out;
3600 lock_release(rtld_bind_lock, &lockstate);
3603 * The value required by the caller is derived from the value
3604 * of the symbol. this is simply the relocated value of the
3607 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3608 sym = make_function_pointer(def, defobj);
3609 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3610 sym = rtld_resolve_ifunc(defobj, def);
3611 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3612 ti.ti_module = defobj->tlsindex;
3613 ti.ti_offset = def->st_value;
3614 sym = __tls_get_addr(&ti);
3616 sym = defobj->relocbase + def->st_value;
3617 LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name);
3621 _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "",
3622 ve != NULL ? ve->name : "");
3623 lock_release(rtld_bind_lock, &lockstate);
3624 LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name);
3629 dlsym(void *handle, const char *name)
3631 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3636 dlfunc(void *handle, const char *name)
3643 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3649 dlvsym(void *handle, const char *name, const char *version)
3653 ventry.name = version;
3655 ventry.hash = elf_hash(version);
3657 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3662 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3664 const Obj_Entry *obj;
3665 RtldLockState lockstate;
3667 rlock_acquire(rtld_bind_lock, &lockstate);
3668 obj = obj_from_addr(addr);
3670 _rtld_error("No shared object contains address");
3671 lock_release(rtld_bind_lock, &lockstate);
3674 rtld_fill_dl_phdr_info(obj, phdr_info);
3675 lock_release(rtld_bind_lock, &lockstate);
3680 dladdr(const void *addr, Dl_info *info)
3682 const Obj_Entry *obj;
3685 unsigned long symoffset;
3686 RtldLockState lockstate;
3688 rlock_acquire(rtld_bind_lock, &lockstate);
3689 obj = obj_from_addr(addr);
3691 _rtld_error("No shared object contains address");
3692 lock_release(rtld_bind_lock, &lockstate);
3695 info->dli_fname = obj->path;
3696 info->dli_fbase = obj->mapbase;
3697 info->dli_saddr = (void *)0;
3698 info->dli_sname = NULL;
3701 * Walk the symbol list looking for the symbol whose address is
3702 * closest to the address sent in.
3704 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3705 def = obj->symtab + symoffset;
3708 * For skip the symbol if st_shndx is either SHN_UNDEF or
3711 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3715 * If the symbol is greater than the specified address, or if it
3716 * is further away from addr than the current nearest symbol,
3719 symbol_addr = obj->relocbase + def->st_value;
3720 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3723 /* Update our idea of the nearest symbol. */
3724 info->dli_sname = obj->strtab + def->st_name;
3725 info->dli_saddr = symbol_addr;
3728 if (info->dli_saddr == addr)
3731 lock_release(rtld_bind_lock, &lockstate);
3736 dlinfo(void *handle, int request, void *p)
3738 const Obj_Entry *obj;
3739 RtldLockState lockstate;
3742 rlock_acquire(rtld_bind_lock, &lockstate);
3744 if (handle == NULL || handle == RTLD_SELF) {
3747 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3748 if ((obj = obj_from_addr(retaddr)) == NULL)
3749 _rtld_error("Cannot determine caller's shared object");
3751 obj = dlcheck(handle);
3754 lock_release(rtld_bind_lock, &lockstate);
3760 case RTLD_DI_LINKMAP:
3761 *((struct link_map const **)p) = &obj->linkmap;
3763 case RTLD_DI_ORIGIN:
3764 error = rtld_dirname(obj->path, p);
3767 case RTLD_DI_SERINFOSIZE:
3768 case RTLD_DI_SERINFO:
3769 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3773 _rtld_error("Invalid request %d passed to dlinfo()", request);
3777 lock_release(rtld_bind_lock, &lockstate);
3783 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3786 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3787 phdr_info->dlpi_name = obj->path;
3788 phdr_info->dlpi_phdr = obj->phdr;
3789 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3790 phdr_info->dlpi_tls_modid = obj->tlsindex;
3791 phdr_info->dlpi_tls_data = obj->tlsinit;
3792 phdr_info->dlpi_adds = obj_loads;
3793 phdr_info->dlpi_subs = obj_loads - obj_count;
3797 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3799 struct dl_phdr_info phdr_info;
3800 Obj_Entry *obj, marker;
3801 RtldLockState bind_lockstate, phdr_lockstate;
3804 init_marker(&marker);
3807 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3808 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3809 for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) {
3810 TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next);
3811 rtld_fill_dl_phdr_info(obj, &phdr_info);
3813 lock_release(rtld_bind_lock, &bind_lockstate);
3815 error = callback(&phdr_info, sizeof phdr_info, param);
3817 wlock_acquire(rtld_bind_lock, &bind_lockstate);
3819 obj = globallist_next(&marker);
3820 TAILQ_REMOVE(&obj_list, &marker, next);
3822 lock_release(rtld_bind_lock, &bind_lockstate);
3823 lock_release(rtld_phdr_lock, &phdr_lockstate);
3829 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3830 lock_release(rtld_bind_lock, &bind_lockstate);
3831 error = callback(&phdr_info, sizeof(phdr_info), param);
3833 lock_release(rtld_phdr_lock, &phdr_lockstate);
3838 fill_search_info(const char *dir, size_t dirlen, void *param)
3840 struct fill_search_info_args *arg;
3844 if (arg->request == RTLD_DI_SERINFOSIZE) {
3845 arg->serinfo->dls_cnt ++;
3846 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3848 struct dl_serpath *s_entry;
3850 s_entry = arg->serpath;
3851 s_entry->dls_name = arg->strspace;
3852 s_entry->dls_flags = arg->flags;
3854 strncpy(arg->strspace, dir, dirlen);
3855 arg->strspace[dirlen] = '\0';
3857 arg->strspace += dirlen + 1;
3865 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3867 struct dl_serinfo _info;
3868 struct fill_search_info_args args;
3870 args.request = RTLD_DI_SERINFOSIZE;
3871 args.serinfo = &_info;
3873 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3876 path_enumerate(obj->rpath, fill_search_info, NULL, &args);
3877 path_enumerate(ld_library_path, fill_search_info, NULL, &args);
3878 path_enumerate(obj->runpath, fill_search_info, NULL, &args);
3879 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args);
3880 if (!obj->z_nodeflib)
3881 path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args);
3884 if (request == RTLD_DI_SERINFOSIZE) {
3885 info->dls_size = _info.dls_size;
3886 info->dls_cnt = _info.dls_cnt;
3890 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3891 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3895 args.request = RTLD_DI_SERINFO;
3896 args.serinfo = info;
3897 args.serpath = &info->dls_serpath[0];
3898 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3900 args.flags = LA_SER_RUNPATH;
3901 if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL)
3904 args.flags = LA_SER_LIBPATH;
3905 if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL)
3908 args.flags = LA_SER_RUNPATH;
3909 if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL)
3912 args.flags = LA_SER_CONFIG;
3913 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args)
3917 args.flags = LA_SER_DEFAULT;
3918 if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path,
3919 fill_search_info, NULL, &args) != NULL)
3925 rtld_dirname(const char *path, char *bname)
3929 /* Empty or NULL string gets treated as "." */
3930 if (path == NULL || *path == '\0') {
3936 /* Strip trailing slashes */
3937 endp = path + strlen(path) - 1;
3938 while (endp > path && *endp == '/')
3941 /* Find the start of the dir */
3942 while (endp > path && *endp != '/')
3945 /* Either the dir is "/" or there are no slashes */
3947 bname[0] = *endp == '/' ? '/' : '.';
3953 } while (endp > path && *endp == '/');
3956 if (endp - path + 2 > PATH_MAX)
3958 _rtld_error("Filename is too long: %s", path);
3962 strncpy(bname, path, endp - path + 1);
3963 bname[endp - path + 1] = '\0';
3968 rtld_dirname_abs(const char *path, char *base)
3972 if (realpath(path, base) == NULL) {
3973 _rtld_error("realpath \"%s\" failed (%s)", path,
3974 rtld_strerror(errno));
3977 dbg("%s -> %s", path, base);
3978 last = strrchr(base, '/');
3980 _rtld_error("non-abs result from realpath \"%s\"", path);
3989 linkmap_add(Obj_Entry *obj)
3991 struct link_map *l, *prev;
3994 l->l_name = obj->path;
3995 l->l_base = obj->mapbase;
3996 l->l_ld = obj->dynamic;
3997 l->l_addr = obj->relocbase;
3999 if (r_debug.r_map == NULL) {
4005 * Scan to the end of the list, but not past the entry for the
4006 * dynamic linker, which we want to keep at the very end.
4008 for (prev = r_debug.r_map;
4009 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
4010 prev = prev->l_next)
4013 /* Link in the new entry. */
4015 l->l_next = prev->l_next;
4016 if (l->l_next != NULL)
4017 l->l_next->l_prev = l;
4022 linkmap_delete(Obj_Entry *obj)
4027 if (l->l_prev == NULL) {
4028 if ((r_debug.r_map = l->l_next) != NULL)
4029 l->l_next->l_prev = NULL;
4033 if ((l->l_prev->l_next = l->l_next) != NULL)
4034 l->l_next->l_prev = l->l_prev;
4038 * Function for the debugger to set a breakpoint on to gain control.
4040 * The two parameters allow the debugger to easily find and determine
4041 * what the runtime loader is doing and to whom it is doing it.
4043 * When the loadhook trap is hit (r_debug_state, set at program
4044 * initialization), the arguments can be found on the stack:
4046 * +8 struct link_map *m
4047 * +4 struct r_debug *rd
4051 r_debug_state(struct r_debug* rd __unused, struct link_map *m __unused)
4054 * The following is a hack to force the compiler to emit calls to
4055 * this function, even when optimizing. If the function is empty,
4056 * the compiler is not obliged to emit any code for calls to it,
4057 * even when marked __noinline. However, gdb depends on those
4060 __compiler_membar();
4064 * A function called after init routines have completed. This can be used to
4065 * break before a program's entry routine is called, and can be used when
4066 * main is not available in the symbol table.
4069 _r_debug_postinit(struct link_map *m __unused)
4072 /* See r_debug_state(). */
4073 __compiler_membar();
4077 release_object(Obj_Entry *obj)
4080 if (obj->holdcount > 0) {
4081 obj->unholdfree = true;
4084 munmap(obj->mapbase, obj->mapsize);
4085 linkmap_delete(obj);
4090 * Get address of the pointer variable in the main program.
4091 * Prefer non-weak symbol over the weak one.
4093 static const void **
4094 get_program_var_addr(const char *name, RtldLockState *lockstate)
4099 symlook_init(&req, name);
4100 req.lockstate = lockstate;
4101 donelist_init(&donelist);
4102 if (symlook_global(&req, &donelist) != 0)
4104 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
4105 return ((const void **)make_function_pointer(req.sym_out,
4107 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
4108 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
4110 return ((const void **)(req.defobj_out->relocbase +
4111 req.sym_out->st_value));
4115 * Set a pointer variable in the main program to the given value. This
4116 * is used to set key variables such as "environ" before any of the
4117 * init functions are called.
4120 set_program_var(const char *name, const void *value)
4124 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
4125 dbg("\"%s\": *%p <-- %p", name, addr, value);
4131 * Search the global objects, including dependencies and main object,
4132 * for the given symbol.
4135 symlook_global(SymLook *req, DoneList *donelist)
4138 const Objlist_Entry *elm;
4141 symlook_init_from_req(&req1, req);
4143 /* Search all objects loaded at program start up. */
4144 if (req->defobj_out == NULL ||
4145 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4146 res = symlook_list(&req1, &list_main, donelist);
4147 if (res == 0 && (req->defobj_out == NULL ||
4148 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4149 req->sym_out = req1.sym_out;
4150 req->defobj_out = req1.defobj_out;
4151 assert(req->defobj_out != NULL);
4155 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
4156 STAILQ_FOREACH(elm, &list_global, link) {
4157 if (req->defobj_out != NULL &&
4158 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4160 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
4161 if (res == 0 && (req->defobj_out == NULL ||
4162 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4163 req->sym_out = req1.sym_out;
4164 req->defobj_out = req1.defobj_out;
4165 assert(req->defobj_out != NULL);
4169 return (req->sym_out != NULL ? 0 : ESRCH);
4173 * Given a symbol name in a referencing object, find the corresponding
4174 * definition of the symbol. Returns a pointer to the symbol, or NULL if
4175 * no definition was found. Returns a pointer to the Obj_Entry of the
4176 * defining object via the reference parameter DEFOBJ_OUT.
4179 symlook_default(SymLook *req, const Obj_Entry *refobj)
4182 const Objlist_Entry *elm;
4186 donelist_init(&donelist);
4187 symlook_init_from_req(&req1, req);
4190 * Look first in the referencing object if linked symbolically,
4191 * and similarly handle protected symbols.
4193 res = symlook_obj(&req1, refobj);
4194 if (res == 0 && (refobj->symbolic ||
4195 ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED)) {
4196 req->sym_out = req1.sym_out;
4197 req->defobj_out = req1.defobj_out;
4198 assert(req->defobj_out != NULL);
4200 if (refobj->symbolic || req->defobj_out != NULL)
4201 donelist_check(&donelist, refobj);
4203 symlook_global(req, &donelist);
4205 /* Search all dlopened DAGs containing the referencing object. */
4206 STAILQ_FOREACH(elm, &refobj->dldags, link) {
4207 if (req->sym_out != NULL &&
4208 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
4210 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
4211 if (res == 0 && (req->sym_out == NULL ||
4212 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
4213 req->sym_out = req1.sym_out;
4214 req->defobj_out = req1.defobj_out;
4215 assert(req->defobj_out != NULL);
4220 * Search the dynamic linker itself, and possibly resolve the
4221 * symbol from there. This is how the application links to
4222 * dynamic linker services such as dlopen.
4224 if (req->sym_out == NULL ||
4225 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
4226 res = symlook_obj(&req1, &obj_rtld);
4228 req->sym_out = req1.sym_out;
4229 req->defobj_out = req1.defobj_out;
4230 assert(req->defobj_out != NULL);
4234 return (req->sym_out != NULL ? 0 : ESRCH);
4238 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
4241 const Obj_Entry *defobj;
4242 const Objlist_Entry *elm;
4248 STAILQ_FOREACH(elm, objlist, link) {
4249 if (donelist_check(dlp, elm->obj))
4251 symlook_init_from_req(&req1, req);
4252 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
4253 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4255 defobj = req1.defobj_out;
4256 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4263 req->defobj_out = defobj;
4270 * Search the chain of DAGS cointed to by the given Needed_Entry
4271 * for a symbol of the given name. Each DAG is scanned completely
4272 * before advancing to the next one. Returns a pointer to the symbol,
4273 * or NULL if no definition was found.
4276 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
4279 const Needed_Entry *n;
4280 const Obj_Entry *defobj;
4286 symlook_init_from_req(&req1, req);
4287 for (n = needed; n != NULL; n = n->next) {
4288 if (n->obj == NULL ||
4289 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
4291 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
4293 defobj = req1.defobj_out;
4294 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
4300 req->defobj_out = defobj;
4307 * Search the symbol table of a single shared object for a symbol of
4308 * the given name and version, if requested. Returns a pointer to the
4309 * symbol, or NULL if no definition was found. If the object is
4310 * filter, return filtered symbol from filtee.
4312 * The symbol's hash value is passed in for efficiency reasons; that
4313 * eliminates many recomputations of the hash value.
4316 symlook_obj(SymLook *req, const Obj_Entry *obj)
4320 int flags, res, mres;
4323 * If there is at least one valid hash at this point, we prefer to
4324 * use the faster GNU version if available.
4326 if (obj->valid_hash_gnu)
4327 mres = symlook_obj1_gnu(req, obj);
4328 else if (obj->valid_hash_sysv)
4329 mres = symlook_obj1_sysv(req, obj);
4334 if (obj->needed_filtees != NULL) {
4335 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4336 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4337 donelist_init(&donelist);
4338 symlook_init_from_req(&req1, req);
4339 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
4341 req->sym_out = req1.sym_out;
4342 req->defobj_out = req1.defobj_out;
4346 if (obj->needed_aux_filtees != NULL) {
4347 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
4348 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
4349 donelist_init(&donelist);
4350 symlook_init_from_req(&req1, req);
4351 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
4353 req->sym_out = req1.sym_out;
4354 req->defobj_out = req1.defobj_out;
4362 /* Symbol match routine common to both hash functions */
4364 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
4365 const unsigned long symnum)
4368 const Elf_Sym *symp;
4371 symp = obj->symtab + symnum;
4372 strp = obj->strtab + symp->st_name;
4374 switch (ELF_ST_TYPE(symp->st_info)) {
4380 if (symp->st_value == 0)
4384 if (symp->st_shndx != SHN_UNDEF)
4387 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
4388 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
4395 if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0)
4398 if (req->ventry == NULL) {
4399 if (obj->versyms != NULL) {
4400 verndx = VER_NDX(obj->versyms[symnum]);
4401 if (verndx > obj->vernum) {
4403 "%s: symbol %s references wrong version %d",
4404 obj->path, obj->strtab + symnum, verndx);
4408 * If we are not called from dlsym (i.e. this
4409 * is a normal relocation from unversioned
4410 * binary), accept the symbol immediately if
4411 * it happens to have first version after this
4412 * shared object became versioned. Otherwise,
4413 * if symbol is versioned and not hidden,
4414 * remember it. If it is the only symbol with
4415 * this name exported by the shared object, it
4416 * will be returned as a match by the calling
4417 * function. If symbol is global (verndx < 2)
4418 * accept it unconditionally.
4420 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
4421 verndx == VER_NDX_GIVEN) {
4422 result->sym_out = symp;
4425 else if (verndx >= VER_NDX_GIVEN) {
4426 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
4428 if (result->vsymp == NULL)
4429 result->vsymp = symp;
4435 result->sym_out = symp;
4438 if (obj->versyms == NULL) {
4439 if (object_match_name(obj, req->ventry->name)) {
4440 _rtld_error("%s: object %s should provide version %s "
4441 "for symbol %s", obj_rtld.path, obj->path,
4442 req->ventry->name, obj->strtab + symnum);
4446 verndx = VER_NDX(obj->versyms[symnum]);
4447 if (verndx > obj->vernum) {
4448 _rtld_error("%s: symbol %s references wrong version %d",
4449 obj->path, obj->strtab + symnum, verndx);
4452 if (obj->vertab[verndx].hash != req->ventry->hash ||
4453 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
4455 * Version does not match. Look if this is a
4456 * global symbol and if it is not hidden. If
4457 * global symbol (verndx < 2) is available,
4458 * use it. Do not return symbol if we are
4459 * called by dlvsym, because dlvsym looks for
4460 * a specific version and default one is not
4461 * what dlvsym wants.
4463 if ((req->flags & SYMLOOK_DLSYM) ||
4464 (verndx >= VER_NDX_GIVEN) ||
4465 (obj->versyms[symnum] & VER_NDX_HIDDEN))
4469 result->sym_out = symp;
4474 * Search for symbol using SysV hash function.
4475 * obj->buckets is known not to be NULL at this point; the test for this was
4476 * performed with the obj->valid_hash_sysv assignment.
4479 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
4481 unsigned long symnum;
4482 Sym_Match_Result matchres;
4484 matchres.sym_out = NULL;
4485 matchres.vsymp = NULL;
4486 matchres.vcount = 0;
4488 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4489 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4490 if (symnum >= obj->nchains)
4491 return (ESRCH); /* Bad object */
4493 if (matched_symbol(req, obj, &matchres, symnum)) {
4494 req->sym_out = matchres.sym_out;
4495 req->defobj_out = obj;
4499 if (matchres.vcount == 1) {
4500 req->sym_out = matchres.vsymp;
4501 req->defobj_out = obj;
4507 /* Search for symbol using GNU hash function */
4509 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4511 Elf_Addr bloom_word;
4512 const Elf32_Word *hashval;
4514 Sym_Match_Result matchres;
4515 unsigned int h1, h2;
4516 unsigned long symnum;
4518 matchres.sym_out = NULL;
4519 matchres.vsymp = NULL;
4520 matchres.vcount = 0;
4522 /* Pick right bitmask word from Bloom filter array */
4523 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4524 obj->maskwords_bm_gnu];
4526 /* Calculate modulus word size of gnu hash and its derivative */
4527 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4528 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4530 /* Filter out the "definitely not in set" queries */
4531 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4534 /* Locate hash chain and corresponding value element*/
4535 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4538 hashval = &obj->chain_zero_gnu[bucket];
4540 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4541 symnum = hashval - obj->chain_zero_gnu;
4542 if (matched_symbol(req, obj, &matchres, symnum)) {
4543 req->sym_out = matchres.sym_out;
4544 req->defobj_out = obj;
4548 } while ((*hashval++ & 1) == 0);
4549 if (matchres.vcount == 1) {
4550 req->sym_out = matchres.vsymp;
4551 req->defobj_out = obj;
4558 trace_loaded_objects(Obj_Entry *obj)
4560 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4563 if ((main_local = getenv(_LD("TRACE_LOADED_OBJECTS_PROGNAME"))) == NULL)
4566 if ((fmt1 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT1"))) == NULL)
4567 fmt1 = "\t%o => %p (%x)\n";
4569 if ((fmt2 = getenv(_LD("TRACE_LOADED_OBJECTS_FMT2"))) == NULL)
4570 fmt2 = "\t%o (%x)\n";
4572 list_containers = getenv(_LD("TRACE_LOADED_OBJECTS_ALL"));
4574 for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4575 Needed_Entry *needed;
4576 const char *name, *path;
4581 if (list_containers && obj->needed != NULL)
4582 rtld_printf("%s:\n", obj->path);
4583 for (needed = obj->needed; needed; needed = needed->next) {
4584 if (needed->obj != NULL) {
4585 if (needed->obj->traced && !list_containers)
4587 needed->obj->traced = true;
4588 path = needed->obj->path;
4592 name = obj->strtab + needed->name;
4593 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4595 fmt = is_lib ? fmt1 : fmt2;
4596 while ((c = *fmt++) != '\0') {
4622 rtld_putstr(main_local);
4625 rtld_putstr(obj_main->path);
4632 rtld_printf("%d", sodp->sod_major);
4635 rtld_printf("%d", sodp->sod_minor);
4642 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4655 * Unload a dlopened object and its dependencies from memory and from
4656 * our data structures. It is assumed that the DAG rooted in the
4657 * object has already been unreferenced, and that the object has a
4658 * reference count of 0.
4661 unload_object(Obj_Entry *root, RtldLockState *lockstate)
4663 Obj_Entry marker, *obj, *next;
4665 assert(root->refcount == 0);
4668 * Pass over the DAG removing unreferenced objects from
4669 * appropriate lists.
4671 unlink_object(root);
4673 /* Unmap all objects that are no longer referenced. */
4674 for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) {
4675 next = TAILQ_NEXT(obj, next);
4676 if (obj->marker || obj->refcount != 0)
4678 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase,
4679 obj->mapsize, 0, obj->path);
4680 dbg("unloading \"%s\"", obj->path);
4682 * Unlink the object now to prevent new references from
4683 * being acquired while the bind lock is dropped in
4684 * recursive dlclose() invocations.
4686 TAILQ_REMOVE(&obj_list, obj, next);
4689 if (obj->filtees_loaded) {
4691 init_marker(&marker);
4692 TAILQ_INSERT_BEFORE(next, &marker, next);
4693 unload_filtees(obj, lockstate);
4694 next = TAILQ_NEXT(&marker, next);
4695 TAILQ_REMOVE(&obj_list, &marker, next);
4697 unload_filtees(obj, lockstate);
4699 release_object(obj);
4704 unlink_object(Obj_Entry *root)
4708 if (root->refcount == 0) {
4709 /* Remove the object from the RTLD_GLOBAL list. */
4710 objlist_remove(&list_global, root);
4712 /* Remove the object from all objects' DAG lists. */
4713 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4714 objlist_remove(&elm->obj->dldags, root);
4715 if (elm->obj != root)
4716 unlink_object(elm->obj);
4722 ref_dag(Obj_Entry *root)
4726 assert(root->dag_inited);
4727 STAILQ_FOREACH(elm, &root->dagmembers, link)
4728 elm->obj->refcount++;
4732 unref_dag(Obj_Entry *root)
4736 assert(root->dag_inited);
4737 STAILQ_FOREACH(elm, &root->dagmembers, link)
4738 elm->obj->refcount--;
4742 * Common code for MD __tls_get_addr().
4744 static void *tls_get_addr_slow(Elf_Addr **, int, size_t) __noinline;
4746 tls_get_addr_slow(Elf_Addr **dtvp, int index, size_t offset)
4748 Elf_Addr *newdtv, *dtv;
4749 RtldLockState lockstate;
4753 /* Check dtv generation in case new modules have arrived */
4754 if (dtv[0] != tls_dtv_generation) {
4755 wlock_acquire(rtld_bind_lock, &lockstate);
4756 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4758 if (to_copy > tls_max_index)
4759 to_copy = tls_max_index;
4760 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4761 newdtv[0] = tls_dtv_generation;
4762 newdtv[1] = tls_max_index;
4764 lock_release(rtld_bind_lock, &lockstate);
4765 dtv = *dtvp = newdtv;
4768 /* Dynamically allocate module TLS if necessary */
4769 if (dtv[index + 1] == 0) {
4770 /* Signal safe, wlock will block out signals. */
4771 wlock_acquire(rtld_bind_lock, &lockstate);
4772 if (!dtv[index + 1])
4773 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4774 lock_release(rtld_bind_lock, &lockstate);
4776 return ((void *)(dtv[index + 1] + offset));
4780 tls_get_addr_common(Elf_Addr **dtvp, int index, size_t offset)
4785 /* Check dtv generation in case new modules have arrived */
4786 if (__predict_true(dtv[0] == tls_dtv_generation &&
4787 dtv[index + 1] != 0))
4788 return ((void *)(dtv[index + 1] + offset));
4789 return (tls_get_addr_slow(dtvp, index, offset));
4792 #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \
4793 defined(__powerpc__) || defined(__riscv)
4796 * Return pointer to allocated TLS block
4799 get_tls_block_ptr(void *tcb, size_t tcbsize)
4801 size_t extra_size, post_size, pre_size, tls_block_size;
4802 size_t tls_init_align;
4804 tls_init_align = MAX(obj_main->tlsalign, 1);
4806 /* Compute fragments sizes. */
4807 extra_size = tcbsize - TLS_TCB_SIZE;
4808 post_size = calculate_tls_post_size(tls_init_align);
4809 tls_block_size = tcbsize + post_size;
4810 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4812 return ((char *)tcb - pre_size - extra_size);
4816 * Allocate Static TLS using the Variant I method.
4818 * For details on the layout, see lib/libc/gen/tls.c.
4820 * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as
4821 * it is based on tls_last_offset, and TLS offsets here are really TCB
4822 * offsets, whereas libc's tls_static_space is just the executable's static
4826 allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign)
4830 Elf_Addr *dtv, **tcb;
4833 size_t extra_size, maxalign, post_size, pre_size, tls_block_size;
4834 size_t tls_init_align, tls_init_offset;
4836 if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE)
4839 assert(tcbsize >= TLS_TCB_SIZE);
4840 maxalign = MAX(tcbalign, tls_static_max_align);
4841 tls_init_align = MAX(obj_main->tlsalign, 1);
4843 /* Compute fragmets sizes. */
4844 extra_size = tcbsize - TLS_TCB_SIZE;
4845 post_size = calculate_tls_post_size(tls_init_align);
4846 tls_block_size = tcbsize + post_size;
4847 pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size;
4848 tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size;
4850 /* Allocate whole TLS block */
4851 tls_block = malloc_aligned(tls_block_size, maxalign, 0);
4852 tcb = (Elf_Addr **)(tls_block + pre_size + extra_size);
4854 if (oldtcb != NULL) {
4855 memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize),
4857 free_aligned(get_tls_block_ptr(oldtcb, tcbsize));
4859 /* Adjust the DTV. */
4861 for (i = 0; i < dtv[1]; i++) {
4862 if (dtv[i+2] >= (Elf_Addr)oldtcb &&
4863 dtv[i+2] < (Elf_Addr)oldtcb + tls_static_space) {
4864 dtv[i+2] = dtv[i+2] - (Elf_Addr)oldtcb + (Elf_Addr)tcb;
4868 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4870 dtv[0] = tls_dtv_generation;
4871 dtv[1] = tls_max_index;
4873 for (obj = globallist_curr(objs); obj != NULL;
4874 obj = globallist_next(obj)) {
4875 if (obj->tlsoffset == 0)
4877 tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1);
4878 addr = (Elf_Addr)tcb + obj->tlsoffset;
4879 if (tls_init_offset > 0)
4880 memset((void *)addr, 0, tls_init_offset);
4881 if (obj->tlsinitsize > 0) {
4882 memcpy((void *)(addr + tls_init_offset), obj->tlsinit,
4885 if (obj->tlssize > obj->tlsinitsize) {
4886 memset((void *)(addr + tls_init_offset + obj->tlsinitsize),
4887 0, obj->tlssize - obj->tlsinitsize - tls_init_offset);
4889 dtv[obj->tlsindex + 1] = addr;
4897 free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused)
4900 Elf_Addr tlsstart, tlsend;
4902 size_t dtvsize, i, tls_init_align;
4904 assert(tcbsize >= TLS_TCB_SIZE);
4905 tls_init_align = MAX(obj_main->tlsalign, 1);
4907 /* Compute fragments sizes. */
4908 post_size = calculate_tls_post_size(tls_init_align);
4910 tlsstart = (Elf_Addr)tcb + TLS_TCB_SIZE + post_size;
4911 tlsend = (Elf_Addr)tcb + tls_static_space;
4913 dtv = *(Elf_Addr **)tcb;
4915 for (i = 0; i < dtvsize; i++) {
4916 if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] >= tlsend)) {
4917 free((void*)dtv[i+2]);
4921 free_aligned(get_tls_block_ptr(tcb, tcbsize));
4926 #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__)
4929 * Allocate Static TLS using the Variant II method.
4932 allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
4935 size_t size, ralign;
4937 Elf_Addr *dtv, *olddtv;
4938 Elf_Addr segbase, oldsegbase, addr;
4942 if (tls_static_max_align > ralign)
4943 ralign = tls_static_max_align;
4944 size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign);
4946 assert(tcbsize >= 2*sizeof(Elf_Addr));
4947 tls = malloc_aligned(size, ralign, 0 /* XXX */);
4948 dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4950 segbase = (Elf_Addr)(tls + roundup(tls_static_space, ralign));
4951 ((Elf_Addr*)segbase)[0] = segbase;
4952 ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
4954 dtv[0] = tls_dtv_generation;
4955 dtv[1] = tls_max_index;
4959 * Copy the static TLS block over whole.
4961 oldsegbase = (Elf_Addr) oldtls;
4962 memcpy((void *)(segbase - tls_static_space),
4963 (const void *)(oldsegbase - tls_static_space),
4967 * If any dynamic TLS blocks have been created tls_get_addr(),
4970 olddtv = ((Elf_Addr**)oldsegbase)[1];
4971 for (i = 0; i < olddtv[1]; i++) {
4972 if (olddtv[i+2] < oldsegbase - size || olddtv[i+2] > oldsegbase) {
4973 dtv[i+2] = olddtv[i+2];
4979 * We assume that this block was the one we created with
4980 * allocate_initial_tls().
4982 free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr));
4984 for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) {
4985 if (obj->marker || obj->tlsoffset == 0)
4987 addr = segbase - obj->tlsoffset;
4988 memset((void*)(addr + obj->tlsinitsize),
4989 0, obj->tlssize - obj->tlsinitsize);
4991 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4992 obj->static_tls_copied = true;
4994 dtv[obj->tlsindex + 1] = addr;
4998 return (void*) segbase;
5002 free_tls(void *tls, size_t tcbsize __unused, size_t tcbalign)
5005 size_t size, ralign;
5007 Elf_Addr tlsstart, tlsend;
5010 * Figure out the size of the initial TLS block so that we can
5011 * find stuff which ___tls_get_addr() allocated dynamically.
5014 if (tls_static_max_align > ralign)
5015 ralign = tls_static_max_align;
5016 size = roundup(tls_static_space, ralign);
5018 dtv = ((Elf_Addr**)tls)[1];
5020 tlsend = (Elf_Addr) tls;
5021 tlsstart = tlsend - size;
5022 for (i = 0; i < dtvsize; i++) {
5023 if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
5024 free_aligned((void *)dtv[i + 2]);
5028 free_aligned((void *)tlsstart);
5035 * Allocate TLS block for module with given index.
5038 allocate_module_tls(int index)
5043 TAILQ_FOREACH(obj, &obj_list, next) {
5046 if (obj->tlsindex == index)
5050 _rtld_error("Can't find module with TLS index %d", index);
5054 p = malloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset);
5055 memcpy(p, obj->tlsinit, obj->tlsinitsize);
5056 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
5061 allocate_tls_offset(Obj_Entry *obj)
5068 if (obj->tlssize == 0) {
5069 obj->tls_done = true;
5073 if (tls_last_offset == 0)
5074 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign,
5077 off = calculate_tls_offset(tls_last_offset, tls_last_size,
5078 obj->tlssize, obj->tlsalign, obj->tlspoffset);
5081 * If we have already fixed the size of the static TLS block, we
5082 * must stay within that size. When allocating the static TLS, we
5083 * leave a small amount of space spare to be used for dynamically
5084 * loading modules which use static TLS.
5086 if (tls_static_space != 0) {
5087 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
5089 } else if (obj->tlsalign > tls_static_max_align) {
5090 tls_static_max_align = obj->tlsalign;
5093 tls_last_offset = obj->tlsoffset = off;
5094 tls_last_size = obj->tlssize;
5095 obj->tls_done = true;
5101 free_tls_offset(Obj_Entry *obj)
5105 * If we were the last thing to allocate out of the static TLS
5106 * block, we give our space back to the 'allocator'. This is a
5107 * simplistic workaround to allow libGL.so.1 to be loaded and
5108 * unloaded multiple times.
5110 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
5111 == calculate_tls_end(tls_last_offset, tls_last_size)) {
5112 tls_last_offset -= obj->tlssize;
5118 _rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign)
5121 RtldLockState lockstate;
5123 wlock_acquire(rtld_bind_lock, &lockstate);
5124 ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtls,
5126 lock_release(rtld_bind_lock, &lockstate);
5131 _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign)
5133 RtldLockState lockstate;
5135 wlock_acquire(rtld_bind_lock, &lockstate);
5136 free_tls(tcb, tcbsize, tcbalign);
5137 lock_release(rtld_bind_lock, &lockstate);
5141 object_add_name(Obj_Entry *obj, const char *name)
5147 entry = malloc(sizeof(Name_Entry) + len);
5149 if (entry != NULL) {
5150 strcpy(entry->name, name);
5151 STAILQ_INSERT_TAIL(&obj->names, entry, link);
5156 object_match_name(const Obj_Entry *obj, const char *name)
5160 STAILQ_FOREACH(entry, &obj->names, link) {
5161 if (strcmp(name, entry->name) == 0)
5168 locate_dependency(const Obj_Entry *obj, const char *name)
5170 const Objlist_Entry *entry;
5171 const Needed_Entry *needed;
5173 STAILQ_FOREACH(entry, &list_main, link) {
5174 if (object_match_name(entry->obj, name))
5178 for (needed = obj->needed; needed != NULL; needed = needed->next) {
5179 if (strcmp(obj->strtab + needed->name, name) == 0 ||
5180 (needed->obj != NULL && object_match_name(needed->obj, name))) {
5182 * If there is DT_NEEDED for the name we are looking for,
5183 * we are all set. Note that object might not be found if
5184 * dependency was not loaded yet, so the function can
5185 * return NULL here. This is expected and handled
5186 * properly by the caller.
5188 return (needed->obj);
5191 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
5197 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
5198 const Elf_Vernaux *vna)
5200 const Elf_Verdef *vd;
5201 const char *vername;
5203 vername = refobj->strtab + vna->vna_name;
5204 vd = depobj->verdef;
5206 _rtld_error("%s: version %s required by %s not defined",
5207 depobj->path, vername, refobj->path);
5211 if (vd->vd_version != VER_DEF_CURRENT) {
5212 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5213 depobj->path, vd->vd_version);
5216 if (vna->vna_hash == vd->vd_hash) {
5217 const Elf_Verdaux *aux = (const Elf_Verdaux *)
5218 ((const char *)vd + vd->vd_aux);
5219 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
5222 if (vd->vd_next == 0)
5224 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5226 if (vna->vna_flags & VER_FLG_WEAK)
5228 _rtld_error("%s: version %s required by %s not found",
5229 depobj->path, vername, refobj->path);
5234 rtld_verify_object_versions(Obj_Entry *obj)
5236 const Elf_Verneed *vn;
5237 const Elf_Verdef *vd;
5238 const Elf_Verdaux *vda;
5239 const Elf_Vernaux *vna;
5240 const Obj_Entry *depobj;
5241 int maxvernum, vernum;
5243 if (obj->ver_checked)
5245 obj->ver_checked = true;
5249 * Walk over defined and required version records and figure out
5250 * max index used by any of them. Do very basic sanity checking
5254 while (vn != NULL) {
5255 if (vn->vn_version != VER_NEED_CURRENT) {
5256 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
5257 obj->path, vn->vn_version);
5260 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5262 vernum = VER_NEED_IDX(vna->vna_other);
5263 if (vernum > maxvernum)
5265 if (vna->vna_next == 0)
5267 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5269 if (vn->vn_next == 0)
5271 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5275 while (vd != NULL) {
5276 if (vd->vd_version != VER_DEF_CURRENT) {
5277 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
5278 obj->path, vd->vd_version);
5281 vernum = VER_DEF_IDX(vd->vd_ndx);
5282 if (vernum > maxvernum)
5284 if (vd->vd_next == 0)
5286 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5293 * Store version information in array indexable by version index.
5294 * Verify that object version requirements are satisfied along the
5297 obj->vernum = maxvernum + 1;
5298 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
5301 while (vd != NULL) {
5302 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
5303 vernum = VER_DEF_IDX(vd->vd_ndx);
5304 assert(vernum <= maxvernum);
5305 vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux);
5306 obj->vertab[vernum].hash = vd->vd_hash;
5307 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
5308 obj->vertab[vernum].file = NULL;
5309 obj->vertab[vernum].flags = 0;
5311 if (vd->vd_next == 0)
5313 vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next);
5317 while (vn != NULL) {
5318 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
5321 vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux);
5323 if (check_object_provided_version(obj, depobj, vna))
5325 vernum = VER_NEED_IDX(vna->vna_other);
5326 assert(vernum <= maxvernum);
5327 obj->vertab[vernum].hash = vna->vna_hash;
5328 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
5329 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
5330 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
5331 VER_INFO_HIDDEN : 0;
5332 if (vna->vna_next == 0)
5334 vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next);
5336 if (vn->vn_next == 0)
5338 vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next);
5344 rtld_verify_versions(const Objlist *objlist)
5346 Objlist_Entry *entry;
5350 STAILQ_FOREACH(entry, objlist, link) {
5352 * Skip dummy objects or objects that have their version requirements
5355 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
5357 if (rtld_verify_object_versions(entry->obj) == -1) {
5359 if (ld_tracing == NULL)
5363 if (rc == 0 || ld_tracing != NULL)
5364 rc = rtld_verify_object_versions(&obj_rtld);
5369 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
5374 vernum = VER_NDX(obj->versyms[symnum]);
5375 if (vernum >= obj->vernum) {
5376 _rtld_error("%s: symbol %s has wrong verneed value %d",
5377 obj->path, obj->strtab + symnum, vernum);
5378 } else if (obj->vertab[vernum].hash != 0) {
5379 return &obj->vertab[vernum];
5386 _rtld_get_stack_prot(void)
5389 return (stack_prot);
5393 _rtld_is_dlopened(void *arg)
5396 RtldLockState lockstate;
5399 rlock_acquire(rtld_bind_lock, &lockstate);
5402 obj = obj_from_addr(arg);
5404 _rtld_error("No shared object contains address");
5405 lock_release(rtld_bind_lock, &lockstate);
5408 res = obj->dlopened ? 1 : 0;
5409 lock_release(rtld_bind_lock, &lockstate);
5414 obj_remap_relro(Obj_Entry *obj, int prot)
5417 if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
5419 _rtld_error("%s: Cannot set relro protection to %#x: %s",
5420 obj->path, prot, rtld_strerror(errno));
5427 obj_disable_relro(Obj_Entry *obj)
5430 return (obj_remap_relro(obj, PROT_READ | PROT_WRITE));
5434 obj_enforce_relro(Obj_Entry *obj)
5437 return (obj_remap_relro(obj, PROT_READ));
5441 map_stacks_exec(RtldLockState *lockstate)
5443 void (*thr_map_stacks_exec)(void);
5445 if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
5447 thr_map_stacks_exec = (void (*)(void))(uintptr_t)
5448 get_program_var_addr("__pthread_map_stacks_exec", lockstate);
5449 if (thr_map_stacks_exec != NULL) {
5450 stack_prot |= PROT_EXEC;
5451 thr_map_stacks_exec();
5456 distribute_static_tls(Objlist *list, RtldLockState *lockstate)
5460 void (*distrib)(size_t, void *, size_t, size_t);
5462 distrib = (void (*)(size_t, void *, size_t, size_t))(uintptr_t)
5463 get_program_var_addr("__pthread_distribute_static_tls", lockstate);
5464 if (distrib == NULL)
5466 STAILQ_FOREACH(elm, list, link) {
5468 if (obj->marker || !obj->tls_done || obj->static_tls_copied)
5470 distrib(obj->tlsoffset, obj->tlsinit, obj->tlsinitsize,
5472 obj->static_tls_copied = true;
5477 symlook_init(SymLook *dst, const char *name)
5480 bzero(dst, sizeof(*dst));
5482 dst->hash = elf_hash(name);
5483 dst->hash_gnu = gnu_hash(name);
5487 symlook_init_from_req(SymLook *dst, const SymLook *src)
5490 dst->name = src->name;
5491 dst->hash = src->hash;
5492 dst->hash_gnu = src->hash_gnu;
5493 dst->ventry = src->ventry;
5494 dst->flags = src->flags;
5495 dst->defobj_out = NULL;
5496 dst->sym_out = NULL;
5497 dst->lockstate = src->lockstate;
5501 open_binary_fd(const char *argv0, bool search_in_path,
5502 const char **binpath_res)
5504 char *binpath, *pathenv, *pe, *res1;
5510 if (search_in_path && strchr(argv0, '/') == NULL) {
5511 binpath = xmalloc(PATH_MAX);
5512 pathenv = getenv("PATH");
5513 if (pathenv == NULL) {
5514 _rtld_error("-p and no PATH environment variable");
5517 pathenv = strdup(pathenv);
5518 if (pathenv == NULL) {
5519 _rtld_error("Cannot allocate memory");
5524 while ((pe = strsep(&pathenv, ":")) != NULL) {
5525 if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX)
5527 if (binpath[0] != '\0' &&
5528 strlcat(binpath, "/", PATH_MAX) >= PATH_MAX)
5530 if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX)
5532 fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY);
5533 if (fd != -1 || errno != ENOENT) {
5540 fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY);
5545 _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno));
5548 if (res != NULL && res[0] != '/') {
5549 res1 = xmalloc(PATH_MAX);
5550 if (realpath(res, res1) != NULL) {
5552 free(__DECONST(char *, res));
5563 * Parse a set of command-line arguments.
5566 parse_args(char* argv[], int argc, bool *use_pathp, int *fdp,
5572 int arglen, fd, i, j, mib[2];
5574 bool seen_b, seen_f;
5576 dbg("Parsing command-line arguments");
5579 seen_b = seen_f = false;
5581 for (i = 1; i < argc; i++ ) {
5583 dbg("argv[%d]: '%s'", i, arg);
5586 * rtld arguments end with an explicit "--" or with the first
5587 * non-prefixed argument.
5589 if (strcmp(arg, "--") == 0) {
5597 * All other arguments are single-character options that can
5598 * be combined, so we need to search through `arg` for them.
5600 arglen = strlen(arg);
5601 for (j = 1; j < arglen; j++) {
5604 print_usage(argv[0]);
5606 } else if (opt == 'b') {
5608 _rtld_error("Both -b and -f specified");
5615 } else if (opt == 'f') {
5617 _rtld_error("Both -b and -f specified");
5622 * -f XX can be used to specify a
5623 * descriptor for the binary named at
5624 * the command line (i.e., the later
5625 * argument will specify the process
5626 * name but the descriptor is what
5627 * will actually be executed).
5629 * -f must be the last option in, e.g., -abcf.
5631 if (j != arglen - 1) {
5632 _rtld_error("Invalid options: %s", arg);
5636 fd = parse_integer(argv[i]);
5639 "Invalid file descriptor: '%s'",
5646 } else if (opt == 'p') {
5648 } else if (opt == 'v') {
5651 mib[1] = HW_MACHINE;
5652 sz = sizeof(machine);
5653 sysctl(mib, nitems(mib), machine, &sz, NULL, 0);
5655 "FreeBSD ld-elf.so.1 %s\n"
5656 "FreeBSD_version %d\n"
5657 "Default lib path %s\n"
5662 __FreeBSD_version, ld_standard_library_path,
5663 ld_env_prefix, ld_elf_hints_default,
5664 ld_path_libmap_conf);
5667 _rtld_error("Invalid argument: '%s'", arg);
5668 print_usage(argv[0]);
5680 * Parse a file descriptor number without pulling in more of libc (e.g. atoi).
5683 parse_integer(const char *str)
5685 static const int RADIX = 10; /* XXXJA: possibly support hex? */
5692 for (c = *str; c != '\0'; c = *++str) {
5693 if (c < '0' || c > '9')
5700 /* Make sure we actually parsed something. */
5707 print_usage(const char *argv0)
5711 "Usage: %s [-h] [-b <exe>] [-f <FD>] [-p] [--] <binary> [<args>]\n"
5714 " -h Display this help message\n"
5715 " -b <exe> Execute <exe> instead of <binary>, arg0 is <binary>\n"
5716 " -f <FD> Execute <FD> instead of searching for <binary>\n"
5717 " -p Search in PATH for named binary\n"
5718 " -v Display identification information\n"
5719 " -- End of RTLD options\n"
5720 " <binary> Name of process to execute\n"
5721 " <args> Arguments to the executed process\n", argv0);
5725 * Overrides for libc_pic-provided functions.
5729 __getosreldate(void)
5739 oid[1] = KERN_OSRELDATE;
5741 len = sizeof(osrel);
5742 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
5743 if (error == 0 && osrel > 0 && len == sizeof(osrel))
5755 void (*__cleanup)(void);
5756 int __isthreaded = 0;
5757 int _thread_autoinit_dummy_decl = 1;
5760 * No unresolved symbols for rtld.
5763 __pthread_cxa_finalize(struct dl_phdr_info *a __unused)
5768 rtld_strerror(int errnum)
5771 if (errnum < 0 || errnum >= sys_nerr)
5772 return ("Unknown error");
5773 return (sys_errlist[errnum]);
5777 * No ifunc relocations.
5780 memset(void *dest, int c, size_t len)
5784 for (i = 0; i < len; i++)
5785 ((char *)dest)[i] = c;
5790 bzero(void *dest, size_t len)
5794 for (i = 0; i < len; i++)
5795 ((char *)dest)[i] = 0;
5800 malloc(size_t nbytes)
5803 return (__crt_malloc(nbytes));
5807 calloc(size_t num, size_t size)
5810 return (__crt_calloc(num, size));
5821 realloc(void *cp, size_t nbytes)
5824 return (__crt_realloc(cp, nbytes));
5827 extern int _rtld_version__FreeBSD_version __exported;
5828 int _rtld_version__FreeBSD_version = __FreeBSD_version;
5830 extern char _rtld_version_laddr_offset __exported;
5831 char _rtld_version_laddr_offset;