2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * Copyright 2009-2012 Konstantin Belousov <kib@FreeBSD.ORG>.
5 * Copyright 2012 John Marino <draco@marino.st>.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * Dynamic linker for ELF.
34 * John Polstra <jdp@polstra.com>.
38 #error "GCC is needed to compile this file"
41 #include <sys/param.h>
42 #include <sys/mount.h>
45 #include <sys/sysctl.h>
47 #include <sys/utsname.h>
48 #include <sys/ktrace.h>
49 #include <sys/resident.h>
52 #include <machine/tls.h>
67 #include "rtld_printf.h"
70 #define PATH_RTLD "/usr/libexec/ld-elf.so.2"
71 #define LD_ARY_CACHE 16
74 typedef void (*func_ptr_type)();
75 typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
78 * Function declarations.
80 static const char *_getenv_ld(const char *id);
81 static void die(void) __dead2;
82 static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **,
83 const Elf_Dyn **, const Elf_Dyn **);
84 static void digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *,
86 static void digest_dynamic(Obj_Entry *, int);
87 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
88 static Obj_Entry *dlcheck(void *);
89 static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj,
90 int lo_flags, int mode, RtldLockState *lockstate);
91 static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int);
92 static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
93 static bool donelist_check(DoneList *, const Obj_Entry *);
94 static void errmsg_restore(char *);
95 static char *errmsg_save(void);
96 static void *fill_search_info(const char *, size_t, void *);
97 static char *find_library(const char *, const Obj_Entry *);
98 static const char *gethints(bool);
99 static void init_dag(Obj_Entry *);
100 static void init_rtld(caddr_t, Elf_Auxinfo **);
101 static void initlist_add_neededs(Needed_Entry *, Objlist *);
102 static void initlist_add_objects(Obj_Entry *, Obj_Entry **, Objlist *);
103 static void linkmap_add(Obj_Entry *);
104 static void linkmap_delete(Obj_Entry *);
105 static void load_filtees(Obj_Entry *, int flags, RtldLockState *);
106 static void unload_filtees(Obj_Entry *);
107 static int load_needed_objects(Obj_Entry *, int);
108 static int load_preload_objects(void);
109 static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
110 static void map_stacks_exec(RtldLockState *);
111 static Obj_Entry *obj_from_addr(const void *);
112 static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
113 static void objlist_call_init(Objlist *, RtldLockState *);
114 static void objlist_clear(Objlist *);
115 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
116 static void objlist_init(Objlist *);
117 static void objlist_push_head(Objlist *, Obj_Entry *);
118 static void objlist_push_tail(Objlist *, Obj_Entry *);
119 static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
120 static void objlist_remove(Objlist *, Obj_Entry *);
121 static void *path_enumerate(const char *, path_enum_proc, void *);
122 static int relocate_object_dag(Obj_Entry *root, bool bind_now,
123 Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
124 static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
125 int flags, RtldLockState *lockstate);
126 static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
128 static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
129 int flags, RtldLockState *lockstate);
130 static int rtld_dirname(const char *, char *);
131 static int rtld_dirname_abs(const char *, char *);
132 static void *rtld_dlopen(const char *name, int fd, int mode);
133 static void rtld_exit(void);
134 static char *search_library_path(const char *, const char *);
135 static const void **get_program_var_addr(const char *, RtldLockState *);
136 static void set_program_var(const char *, const void *);
137 static int symlook_default(SymLook *, const Obj_Entry *refobj);
138 static int symlook_global(SymLook *, DoneList *);
139 static void symlook_init_from_req(SymLook *, const SymLook *);
140 static int symlook_list(SymLook *, const Objlist *, DoneList *);
141 static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *);
142 static int symlook_obj1_sysv(SymLook *, const Obj_Entry *);
143 static int symlook_obj1_gnu(SymLook *, const Obj_Entry *);
144 static void trace_loaded_objects(Obj_Entry *);
145 static void unlink_object(Obj_Entry *);
146 static void unload_object(Obj_Entry *);
147 static void unref_dag(Obj_Entry *);
148 static void ref_dag(Obj_Entry *);
149 static char *origin_subst_one(char *, const char *, const char *, bool);
150 static char *origin_subst(char *, const char *);
151 static void preinit_main(void);
152 static int rtld_verify_versions(const Objlist *);
153 static int rtld_verify_object_versions(Obj_Entry *);
154 static void object_add_name(Obj_Entry *, const char *);
155 static int object_match_name(const Obj_Entry *, const char *);
156 static void ld_utrace_log(int, void *, void *, size_t, int, const char *);
157 static void rtld_fill_dl_phdr_info(const Obj_Entry *obj,
158 struct dl_phdr_info *phdr_info);
159 static uint_fast32_t gnu_hash (const char *);
160 static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *,
161 const unsigned long);
163 void r_debug_state(struct r_debug *, struct link_map *) __noinline;
168 static char *error_message; /* Message for dlerror(), or NULL */
169 struct r_debug r_debug; /* for GDB; */
170 static bool libmap_disable; /* Disable libmap */
171 static bool ld_loadfltr; /* Immediate filters processing */
172 static char *libmap_override; /* Maps to use in addition to libmap.conf */
173 static bool trust; /* False for setuid and setgid programs */
174 static bool dangerous_ld_env; /* True if environment variables have been
175 used to affect the libraries loaded */
176 static const char *ld_bind_now; /* Environment variable for immediate binding */
177 static const char *ld_debug; /* Environment variable for debugging */
178 static const char *ld_library_path; /* Environment variable for search path */
179 static char *ld_preload; /* Environment variable for libraries to
181 static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */
182 static const char *ld_tracing; /* Called from ldd to print libs */
183 static const char *ld_utrace; /* Use utrace() to log events. */
184 static int (*rtld_functrace)( /* Optional function call tracing hook */
185 const char *caller_obj,
186 const char *callee_obj,
187 const char *callee_func,
189 static const Obj_Entry *rtld_functrace_obj; /* Object thereof */
190 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
191 static Obj_Entry **obj_tail; /* Link field of last object in list */
192 static Obj_Entry **preload_tail;
193 static Obj_Entry *obj_main; /* The main program shared object */
194 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
195 static unsigned int obj_count; /* Number of objects in obj_list */
196 static unsigned int obj_loads; /* Number of objects in obj_list */
198 static int ld_resident; /* Non-zero if resident */
199 static const char *ld_ary[LD_ARY_CACHE];
201 static Objlist initlist;
203 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
204 STAILQ_HEAD_INITIALIZER(list_global);
205 static Objlist list_main = /* Objects loaded at program startup */
206 STAILQ_HEAD_INITIALIZER(list_main);
207 static Objlist list_fini = /* Objects needing fini() calls */
208 STAILQ_HEAD_INITIALIZER(list_fini);
210 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
211 const char *__ld_sharedlib_base;
213 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
215 extern Elf_Dyn _DYNAMIC;
216 #pragma weak _DYNAMIC
217 #ifndef RTLD_IS_DYNAMIC
218 #define RTLD_IS_DYNAMIC() (&_DYNAMIC != NULL)
221 #ifdef ENABLE_OSRELDATE
225 static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC;
226 static int max_stack_flags;
229 * Global declarations normally provided by crt1. The dynamic linker is
230 * not built with crt1, so we have to provide them ourselves.
236 * Used to pass argc, argv to init functions.
242 * Globals to control TLS allocation.
244 size_t tls_last_offset; /* Static TLS offset of last module */
245 size_t tls_last_size; /* Static TLS size of last module */
246 size_t tls_static_space; /* Static TLS space allocated */
247 int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
248 int tls_max_index = 1; /* Largest module index allocated */
251 * Fill in a DoneList with an allocation large enough to hold all of
252 * the currently-loaded objects. Keep this as a macro since it calls
253 * alloca and we want that to occur within the scope of the caller.
255 #define donelist_init(dlp) \
256 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
257 assert((dlp)->objs != NULL), \
258 (dlp)->num_alloc = obj_count, \
261 #define UTRACE_DLOPEN_START 1
262 #define UTRACE_DLOPEN_STOP 2
263 #define UTRACE_DLCLOSE_START 3
264 #define UTRACE_DLCLOSE_STOP 4
265 #define UTRACE_LOAD_OBJECT 5
266 #define UTRACE_UNLOAD_OBJECT 6
267 #define UTRACE_ADD_RUNDEP 7
268 #define UTRACE_PRELOAD_FINISHED 8
269 #define UTRACE_INIT_CALL 9
270 #define UTRACE_FINI_CALL 10
273 char sig[4]; /* 'RTLD' */
276 void *mapbase; /* Used for 'parent' and 'init/fini' */
278 int refcnt; /* Used for 'mode' */
279 char name[MAXPATHLEN];
282 #define LD_UTRACE(e, h, mb, ms, r, n) do { \
283 if (ld_utrace != NULL) \
284 ld_utrace_log(e, h, mb, ms, r, n); \
288 ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize,
289 int refcnt, const char *name)
291 struct utrace_rtld ut;
299 ut.mapbase = mapbase;
300 ut.mapsize = mapsize;
302 bzero(ut.name, sizeof(ut.name));
304 strlcpy(ut.name, name, sizeof(ut.name));
305 utrace(&ut, sizeof(ut));
309 * Main entry point for dynamic linking. The first argument is the
310 * stack pointer. The stack is expected to be laid out as described
311 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
312 * Specifically, the stack pointer points to a word containing
313 * ARGC. Following that in the stack is a null-terminated sequence
314 * of pointers to argument strings. Then comes a null-terminated
315 * sequence of pointers to environment strings. Finally, there is a
316 * sequence of "auxiliary vector" entries.
318 * The second argument points to a place to store the dynamic linker's
319 * exit procedure pointer and the third to a place to store the main
322 * The return value is the main program's entry point.
325 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
327 Obj_Entry *last_interposer;
328 Elf_Auxinfo *aux_info[AT_COUNT];
336 Objlist_Entry *entry;
339 /* marino: DO NOT MOVE THESE VARIABLES TO _rtld
340 Obj_Entry **preload_tail;
342 from global to here. It will break the DWARF2 unwind scheme.
343 The system compilers were unaffected, but not gcc 4.6
347 * On entry, the dynamic linker itself has not been relocated yet.
348 * Be very careful not to reference any global data until after
349 * init_rtld has returned. It is OK to reference file-scope statics
350 * and string constants, and to call static and global functions.
353 /* Find the auxiliary vector on the stack. */
356 sp += argc + 1; /* Skip over arguments and NULL terminator */
360 * If we aren't already resident we have to dig out some more info.
361 * Note that auxinfo does not exist when we are resident.
363 * I'm not sure about the ld_resident check. It seems to read zero
364 * prior to relocation, which is what we want. When running from a
365 * resident copy everything will be relocated so we are definitely
368 if (ld_resident == 0) {
369 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
371 aux = (Elf_Auxinfo *) sp;
373 /* Digest the auxiliary vector. */
374 for (i = 0; i < AT_COUNT; i++)
376 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
377 if (auxp->a_type < AT_COUNT)
378 aux_info[auxp->a_type] = auxp;
381 /* Initialize and relocate ourselves. */
382 assert(aux_info[AT_BASE] != NULL);
383 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr, aux_info);
386 ld_index = 0; /* don't use old env cache in case we are resident */
387 __progname = obj_rtld.path;
388 argv0 = argv[0] != NULL ? argv[0] : "(null)";
393 trust = !issetugid();
395 ld_bind_now = _getenv_ld("LD_BIND_NOW");
397 * If the process is tainted, then we un-set the dangerous environment
398 * variables. The process will be marked as tainted until setuid(2)
399 * is called. If any child process calls setuid(2) we do not want any
400 * future processes to honor the potentially un-safe variables.
403 if ( unsetenv("LD_DEBUG")
404 || unsetenv("LD_PRELOAD")
405 || unsetenv("LD_LIBRARY_PATH")
406 || unsetenv("LD_ELF_HINTS_PATH")
407 || unsetenv("LD_LIBMAP")
408 || unsetenv("LD_LIBMAP_DISABLE")
409 || unsetenv("LD_LOADFLTR")
410 || unsetenv("LD_SHAREDLIB_BASE")
412 _rtld_error("environment corrupt; aborting");
416 __ld_sharedlib_base = _getenv_ld("LD_SHAREDLIB_BASE");
417 ld_debug = _getenv_ld("LD_DEBUG");
418 libmap_disable = _getenv_ld("LD_LIBMAP_DISABLE") != NULL;
419 libmap_override = (char *)_getenv_ld("LD_LIBMAP");
420 ld_library_path = _getenv_ld("LD_LIBRARY_PATH");
421 ld_preload = (char *)_getenv_ld("LD_PRELOAD");
422 ld_elf_hints_path = _getenv_ld("LD_ELF_HINTS_PATH");
423 ld_loadfltr = _getenv_ld("LD_LOADFLTR") != NULL;
424 dangerous_ld_env = (ld_library_path != NULL)
425 || (ld_preload != NULL)
426 || (ld_elf_hints_path != NULL)
428 || (libmap_override != NULL)
431 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS");
432 ld_utrace = _getenv_ld("LD_UTRACE");
434 if ((ld_elf_hints_path == NULL) || strlen(ld_elf_hints_path) == 0)
435 ld_elf_hints_path = _PATH_ELF_HINTS;
437 if (ld_debug != NULL && *ld_debug != '\0')
439 dbg("%s is initialized, base address = %p", __progname,
440 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
441 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
442 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
444 dbg("initializing thread locks");
448 * If we are resident we can skip work that we have already done.
449 * Note that the stack is reset and there is no Elf_Auxinfo
450 * when running from a resident image, and the static globals setup
451 * between here and resident_skip will have already been setup.
457 * Load the main program, or process its program header if it is
460 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
461 int fd = aux_info[AT_EXECFD]->a_un.a_val;
462 dbg("loading main program");
463 obj_main = map_object(fd, argv0, NULL);
465 if (obj_main == NULL)
467 max_stack_flags = obj->stack_flags;
468 } else { /* Main program already loaded. */
469 const Elf_Phdr *phdr;
473 dbg("processing main program's program header");
474 assert(aux_info[AT_PHDR] != NULL);
475 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
476 assert(aux_info[AT_PHNUM] != NULL);
477 phnum = aux_info[AT_PHNUM]->a_un.a_val;
478 assert(aux_info[AT_PHENT] != NULL);
479 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
480 assert(aux_info[AT_ENTRY] != NULL);
481 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
482 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
486 char buf[MAXPATHLEN];
487 if (aux_info[AT_EXECPATH] != NULL) {
490 kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr;
491 dbg("AT_EXECPATH %p %s", kexecpath, kexecpath);
492 if (kexecpath[0] == '/')
493 obj_main->path = kexecpath;
494 else if (getcwd(buf, sizeof(buf)) == NULL ||
495 strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) ||
496 strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf))
497 obj_main->path = xstrdup(argv0);
499 obj_main->path = xstrdup(buf);
501 char resolved[MAXPATHLEN];
502 dbg("No AT_EXECPATH");
503 if (argv0[0] == '/') {
504 if (realpath(argv0, resolved) != NULL)
505 obj_main->path = xstrdup(resolved);
507 obj_main->path = xstrdup(argv0);
509 if (getcwd(buf, sizeof(buf)) != NULL
510 && strlcat(buf, "/", sizeof(buf)) < sizeof(buf)
511 && strlcat(buf, argv0, sizeof (buf)) < sizeof(buf)
512 && access(buf, R_OK) == 0
513 && realpath(buf, resolved) != NULL)
514 obj_main->path = xstrdup(resolved);
516 obj_main->path = xstrdup(argv0);
519 dbg("obj_main path %s", obj_main->path);
520 obj_main->mainprog = true;
522 if (aux_info[AT_STACKPROT] != NULL &&
523 aux_info[AT_STACKPROT]->a_un.a_val != 0)
524 stack_prot = aux_info[AT_STACKPROT]->a_un.a_val;
527 * Get the actual dynamic linker pathname from the executable if
528 * possible. (It should always be possible.) That ensures that
529 * gdb will find the right dynamic linker even if a non-standard
532 if (obj_main->interp != NULL &&
533 strcmp(obj_main->interp, obj_rtld.path) != 0) {
535 obj_rtld.path = xstrdup(obj_main->interp);
536 __progname = obj_rtld.path;
539 digest_dynamic(obj_main, 0);
540 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d",
541 obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu,
542 obj_main->dynsymcount);
544 linkmap_add(obj_main);
545 linkmap_add(&obj_rtld);
547 /* Link the main program into the list of objects. */
548 *obj_tail = obj_main;
549 obj_tail = &obj_main->next;
553 /* Initialize a fake symbol for resolving undefined weak references. */
554 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
555 sym_zero.st_shndx = SHN_UNDEF;
556 sym_zero.st_value = -(uintptr_t)obj_main->relocbase;
559 libmap_disable = (bool)lm_init(libmap_override);
561 dbg("loading LD_PRELOAD libraries");
562 if (load_preload_objects() == -1)
564 preload_tail = obj_tail;
566 dbg("loading needed objects");
567 if (load_needed_objects(obj_main, 0) == -1)
570 /* Make a list of all objects loaded at startup. */
571 last_interposer = obj_main;
572 for (obj = obj_list; obj != NULL; obj = obj->next) {
573 if (obj->z_interpose && obj != obj_main) {
574 objlist_put_after(&list_main, last_interposer, obj);
575 last_interposer = obj;
577 objlist_push_tail(&list_main, obj);
582 dbg("checking for required versions");
583 if (rtld_verify_versions(&list_main) == -1 && !ld_tracing)
588 if (ld_tracing) { /* We're done */
589 trace_loaded_objects(obj_main);
593 if (ld_resident) /* XXX clean this up! */
596 if (_getenv_ld("LD_DUMP_REL_PRE") != NULL) {
597 dump_relocations(obj_main);
601 /* setup TLS for main thread */
602 dbg("initializing initial thread local storage");
603 STAILQ_FOREACH(entry, &list_main, link) {
605 * Allocate all the initial objects out of the static TLS
606 * block even if they didn't ask for it.
608 allocate_tls_offset(entry->obj);
611 tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA;
614 * Do not try to allocate the TLS here, let libc do it itself.
615 * (crt1 for the program will call _init_tls())
618 if (relocate_objects(obj_main,
619 ld_bind_now != NULL && *ld_bind_now != '\0',
620 &obj_rtld, SYMLOOK_EARLY, NULL) == -1)
623 dbg("doing copy relocations");
624 if (do_copy_relocations(obj_main) == -1)
629 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) {
630 if (exec_sys_unregister(-1) < 0) {
631 dbg("exec_sys_unregister failed %d\n", errno);
634 dbg("exec_sys_unregister success\n");
638 if (_getenv_ld("LD_DUMP_REL_POST") != NULL) {
639 dump_relocations(obj_main);
643 dbg("initializing key program variables");
644 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
645 set_program_var("environ", env);
646 set_program_var("__elf_aux_vector", aux);
648 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) {
649 extern void resident_start(void);
651 if (exec_sys_register(resident_start) < 0) {
652 dbg("exec_sys_register failed %d\n", errno);
655 dbg("exec_sys_register success\n");
659 /* Make a list of init functions to call. */
660 objlist_init(&initlist);
661 initlist_add_objects(obj_list, preload_tail, &initlist);
663 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
665 map_stacks_exec(NULL);
667 dbg("resolving ifuncs");
668 if (resolve_objects_ifunc(obj_main,
669 ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY,
674 * Do NOT call the initlist here, give libc a chance to set up
675 * the initial TLS segment. crt1 will then call _rtld_call_init().
678 dbg("transferring control to program entry point = %p", obj_main->entry);
680 /* Return the exit procedure and the program entry point. */
681 *exit_proc = rtld_exit;
683 return (func_ptr_type) obj_main->entry;
687 * Call the initialization list for dynamically loaded libraries.
688 * (called from crt1.c).
691 _rtld_call_init(void)
693 RtldLockState lockstate;
696 if (!obj_main->note_present && obj_main->valid_hash_gnu) {
698 * The use of a linker script with a PHDRS directive that does not include
699 * PT_NOTE will block the crt_no_init note. In this case we'll look for the
700 * recently added GNU hash dynamic tag which gets built by default. It is
701 * extremely unlikely to find a pre-3.1 binary without a PT_NOTE header and
702 * a gnu hash tag. If gnu hash found, consider binary to use new crt code.
704 obj_main->crt_no_init = true;
705 dbg("Setting crt_no_init without presence of PT_NOTE header");
708 wlock_acquire(rtld_bind_lock, &lockstate);
709 if (obj_main->crt_no_init)
713 * Make sure we don't call the main program's init and fini functions
714 * for binaries linked with old crt1 which calls _init itself.
716 obj_main->init = obj_main->fini = (Elf_Addr)NULL;
717 obj_main->init_array = obj_main->fini_array = (Elf_Addr)NULL;
719 objlist_call_init(&initlist, &lockstate);
720 objlist_clear(&initlist);
721 dbg("loading filtees");
722 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
723 if (ld_loadfltr || obj->z_loadfltr)
724 load_filtees(obj, 0, &lockstate);
726 lock_release(rtld_bind_lock, &lockstate);
730 rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def)
735 ptr = (void *)make_function_pointer(def, obj);
736 target = ((Elf_Addr (*)(void))ptr)();
737 return ((void *)target);
741 _rtld_bind(Obj_Entry *obj, Elf_Size reloff, void *stack)
745 const Obj_Entry *defobj;
748 RtldLockState lockstate;
750 rlock_acquire(rtld_bind_lock, &lockstate);
751 if (sigsetjmp(lockstate.env, 0) != 0)
752 lock_upgrade(rtld_bind_lock, &lockstate);
754 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
756 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
758 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
759 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL,
763 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
764 target = (Elf_Addr)rtld_resolve_ifunc(defobj, def);
766 target = (Elf_Addr)(defobj->relocbase + def->st_value);
768 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
769 defobj->strtab + def->st_name, basename(obj->path),
770 (void *)target, basename(defobj->path));
773 * If we have a function call tracing hook, and the
774 * hook would like to keep tracing this one function,
775 * prevent the relocation so we will wind up here
776 * the next time again.
778 * We don't want to functrace calls from the functracer
779 * to avoid recursive loops.
781 if (rtld_functrace != NULL && obj != rtld_functrace_obj) {
782 if (rtld_functrace(obj->path,
784 defobj->strtab + def->st_name,
786 lock_release(rtld_bind_lock, &lockstate);
792 * Write the new contents for the jmpslot. Note that depending on
793 * architecture, the value which we need to return back to the
794 * lazy binding trampoline may or may not be the target
795 * address. The value returned from reloc_jmpslot() is the value
796 * that the trampoline needs.
798 target = reloc_jmpslot(where, target, defobj, obj, rel);
799 lock_release(rtld_bind_lock, &lockstate);
804 * Error reporting function. Use it like printf. If formats the message
805 * into a buffer, and sets things up so that the next call to dlerror()
806 * will return the message.
809 _rtld_error(const char *fmt, ...)
811 static char buf[512];
815 rtld_vsnprintf(buf, sizeof buf, fmt, ap);
821 * Return a dynamically-allocated copy of the current error message, if any.
826 return error_message == NULL ? NULL : xstrdup(error_message);
830 * Restore the current error message from a copy which was previously saved
831 * by errmsg_save(). The copy is freed.
834 errmsg_restore(char *saved_msg)
836 if (saved_msg == NULL)
837 error_message = NULL;
839 _rtld_error("%s", saved_msg);
845 basename(const char *name)
847 const char *p = strrchr(name, '/');
848 return p != NULL ? p + 1 : name;
851 static struct utsname uts;
854 origin_subst_one(char *real, const char *kw, const char *subst,
857 char *p, *p1, *res, *resp;
858 int subst_len, kw_len, subst_count, old_len, new_len;
863 * First, count the number of the keyword occurences, to
864 * preallocate the final string.
866 for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) {
873 * If the keyword is not found, just return.
875 if (subst_count == 0)
876 return (may_free ? real : xstrdup(real));
879 * There is indeed something to substitute. Calculate the
880 * length of the resulting string, and allocate it.
882 subst_len = strlen(subst);
883 old_len = strlen(real);
884 new_len = old_len + (subst_len - kw_len) * subst_count;
885 res = xmalloc(new_len + 1);
888 * Now, execute the substitution loop.
890 for (p = real, resp = res, *resp = '\0';;) {
893 /* Copy the prefix before keyword. */
894 memcpy(resp, p, p1 - p);
896 /* Keyword replacement. */
897 memcpy(resp, subst, subst_len);
905 /* Copy to the end of string and finish. */
913 origin_subst(char *real, const char *origin_path)
915 char *res1, *res2, *res3, *res4;
917 if (uts.sysname[0] == '\0') {
918 if (uname(&uts) != 0) {
919 _rtld_error("utsname failed: %d", errno);
923 res1 = origin_subst_one(real, "$ORIGIN", origin_path, false);
924 res2 = origin_subst_one(res1, "$OSNAME", uts.sysname, true);
925 res3 = origin_subst_one(res2, "$OSREL", uts.release, true);
926 res4 = origin_subst_one(res3, "$PLATFORM", uts.machine, true);
933 const char *msg = dlerror();
937 rtld_fdputstr(STDERR_FILENO, msg);
938 rtld_fdputchar(STDERR_FILENO, '\n');
943 * Process a shared object's DYNAMIC section, and save the important
944 * information in its Obj_Entry structure.
947 digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
948 const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath)
951 Needed_Entry **needed_tail = &obj->needed;
952 Needed_Entry **needed_filtees_tail = &obj->needed_filtees;
953 Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees;
954 const Elf_Hashelt *hashtab;
955 const Elf32_Word *hashval;
956 Elf32_Word bkt, nmaskwords;
959 int plttype = DT_REL;
965 obj->bind_now = false;
966 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
967 switch (dynp->d_tag) {
970 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
974 obj->relsize = dynp->d_un.d_val;
978 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
982 obj->pltrel = (const Elf_Rel *)
983 (obj->relocbase + dynp->d_un.d_ptr);
987 obj->pltrelsize = dynp->d_un.d_val;
991 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
995 obj->relasize = dynp->d_un.d_val;
999 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
1003 plttype = dynp->d_un.d_val;
1004 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
1008 obj->symtab = (const Elf_Sym *)
1009 (obj->relocbase + dynp->d_un.d_ptr);
1013 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
1017 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
1021 obj->strsize = dynp->d_un.d_val;
1025 obj->verneed = (const Elf_Verneed *) (obj->relocbase +
1030 obj->verneednum = dynp->d_un.d_val;
1034 obj->verdef = (const Elf_Verdef *) (obj->relocbase +
1039 obj->verdefnum = dynp->d_un.d_val;
1043 obj->versyms = (const Elf_Versym *)(obj->relocbase +
1049 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1051 obj->nbuckets = hashtab[0];
1052 obj->nchains = hashtab[1];
1053 obj->buckets = hashtab + 2;
1054 obj->chains = obj->buckets + obj->nbuckets;
1055 obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 &&
1056 obj->buckets != NULL;
1062 hashtab = (const Elf_Hashelt *)(obj->relocbase +
1064 obj->nbuckets_gnu = hashtab[0];
1065 obj->symndx_gnu = hashtab[1];
1066 nmaskwords = hashtab[2];
1067 bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords;
1068 /* Number of bitmask words is required to be power of 2 */
1069 nmw_power2 = ((nmaskwords & (nmaskwords - 1)) == 0);
1070 obj->maskwords_bm_gnu = nmaskwords - 1;
1071 obj->shift2_gnu = hashtab[3];
1072 obj->bloom_gnu = (Elf_Addr *) (hashtab + 4);
1073 obj->buckets_gnu = hashtab + 4 + bloom_size32;
1074 obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu -
1076 obj->valid_hash_gnu = nmw_power2 && obj->nbuckets_gnu > 0 &&
1077 obj->buckets_gnu != NULL;
1083 Needed_Entry *nep = NEW(Needed_Entry);
1084 nep->name = dynp->d_un.d_val;
1089 needed_tail = &nep->next;
1095 Needed_Entry *nep = NEW(Needed_Entry);
1096 nep->name = dynp->d_un.d_val;
1100 *needed_filtees_tail = nep;
1101 needed_filtees_tail = &nep->next;
1107 Needed_Entry *nep = NEW(Needed_Entry);
1108 nep->name = dynp->d_un.d_val;
1112 *needed_aux_filtees_tail = nep;
1113 needed_aux_filtees_tail = &nep->next;
1118 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
1122 obj->textrel = true;
1126 obj->symbolic = true;
1131 * We have to wait until later to process this, because we
1132 * might not have gotten the address of the string table yet.
1142 *dyn_runpath = dynp;
1146 obj->init = (Elf_Addr) (obj->relocbase + dynp->d_un.d_ptr);
1150 obj->fini = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1153 case DT_PREINIT_ARRAY:
1154 obj->preinit_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1158 obj->init_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1162 obj->fini_array = (Elf_Addr)(obj->relocbase + dynp->d_un.d_ptr);
1165 case DT_PREINIT_ARRAYSZ:
1166 obj->preinit_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1169 case DT_INIT_ARRAYSZ:
1170 obj->init_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1173 case DT_FINI_ARRAYSZ:
1174 obj->fini_array_num = dynp->d_un.d_val / sizeof(Elf_Addr);
1178 /* XXX - not implemented yet */
1180 dbg("Filling in DT_DEBUG entry");
1181 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
1185 if ((dynp->d_un.d_val & DF_ORIGIN) && trust)
1186 obj->z_origin = true;
1187 if (dynp->d_un.d_val & DF_SYMBOLIC)
1188 obj->symbolic = true;
1189 if (dynp->d_un.d_val & DF_TEXTREL)
1190 obj->textrel = true;
1191 if (dynp->d_un.d_val & DF_BIND_NOW)
1192 obj->bind_now = true;
1193 /*if (dynp->d_un.d_val & DF_STATIC_TLS)
1198 if (dynp->d_un.d_val & DF_1_NOOPEN)
1199 obj->z_noopen = true;
1200 if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
1201 obj->z_origin = true;
1202 /*if (dynp->d_un.d_val & DF_1_GLOBAL)
1204 if (dynp->d_un.d_val & DF_1_BIND_NOW)
1205 obj->bind_now = true;
1206 if (dynp->d_un.d_val & DF_1_NODELETE)
1207 obj->z_nodelete = true;
1208 if (dynp->d_un.d_val & DF_1_LOADFLTR)
1209 obj->z_loadfltr = true;
1210 if (dynp->d_un.d_val & DF_1_INTERPOSE)
1211 obj->z_interpose = true;
1212 if (dynp->d_un.d_val & DF_1_NODEFLIB)
1213 obj->z_nodeflib = true;
1218 dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag,
1225 obj->traced = false;
1227 if (plttype == DT_RELA) {
1228 obj->pltrela = (const Elf_Rela *) obj->pltrel;
1230 obj->pltrelasize = obj->pltrelsize;
1231 obj->pltrelsize = 0;
1234 /* Determine size of dynsym table (equal to nchains of sysv hash) */
1235 if (obj->valid_hash_sysv)
1236 obj->dynsymcount = obj->nchains;
1237 else if (obj->valid_hash_gnu) {
1238 obj->dynsymcount = 0;
1239 for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) {
1240 if (obj->buckets_gnu[bkt] == 0)
1242 hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]];
1245 while ((*hashval++ & 1u) == 0);
1247 obj->dynsymcount += obj->symndx_gnu;
1252 digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath,
1253 const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath)
1256 if (obj->z_origin && obj->origin_path == NULL) {
1257 obj->origin_path = xmalloc(PATH_MAX);
1258 if (rtld_dirname_abs(obj->path, obj->origin_path) == -1)
1262 if (dyn_runpath != NULL) {
1263 obj->runpath = (char *)obj->strtab + dyn_runpath->d_un.d_val;
1265 obj->runpath = origin_subst(obj->runpath, obj->origin_path);
1267 else if (dyn_rpath != NULL) {
1268 obj->rpath = (char *)obj->strtab + dyn_rpath->d_un.d_val;
1270 obj->rpath = origin_subst(obj->rpath, obj->origin_path);
1273 if (dyn_soname != NULL)
1274 object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val);
1278 digest_dynamic(Obj_Entry *obj, int early)
1280 const Elf_Dyn *dyn_rpath;
1281 const Elf_Dyn *dyn_soname;
1282 const Elf_Dyn *dyn_runpath;
1284 digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath);
1285 digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath);
1289 * Process a shared object's program header. This is used only for the
1290 * main program, when the kernel has already loaded the main program
1291 * into memory before calling the dynamic linker. It creates and
1292 * returns an Obj_Entry structure.
1295 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
1298 const Elf_Phdr *phlimit = phdr + phnum;
1300 Elf_Addr note_start, note_end;
1304 for (ph = phdr; ph < phlimit; ph++) {
1305 if (ph->p_type != PT_PHDR)
1309 obj->phsize = ph->p_memsz;
1310 obj->relocbase = (caddr_t)phdr - ph->p_vaddr;
1314 obj->stack_flags = PF_X | PF_R | PF_W;
1316 for (ph = phdr; ph < phlimit; ph++) {
1317 switch (ph->p_type) {
1320 obj->interp = (const char *)(ph->p_vaddr + obj->relocbase);
1324 if (nsegs == 0) { /* First load segment */
1325 obj->vaddrbase = trunc_page(ph->p_vaddr);
1326 obj->mapbase = obj->vaddrbase + obj->relocbase;
1327 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
1329 } else { /* Last load segment */
1330 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
1337 obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase);
1342 obj->tlssize = ph->p_memsz;
1343 obj->tlsalign = ph->p_align;
1344 obj->tlsinitsize = ph->p_filesz;
1345 obj->tlsinit = (void*)(ph->p_vaddr + obj->relocbase);
1349 obj->stack_flags = ph->p_flags;
1353 obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr);
1354 obj->relro_size = round_page(ph->p_memsz);
1358 obj->note_present = true;
1359 note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr;
1360 note_end = note_start + ph->p_filesz;
1361 digest_notes(obj, note_start, note_end);
1366 _rtld_error("%s: too few PT_LOAD segments", path);
1375 digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end)
1377 const Elf_Note *note;
1378 const char *note_name;
1381 for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end;
1382 note = (const Elf_Note *)((const char *)(note + 1) +
1383 roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
1384 roundup2(note->n_descsz, sizeof(Elf32_Addr)))) {
1385 if (note->n_namesz != sizeof(NOTE_VENDOR) ||
1386 note->n_descsz != sizeof(int32_t))
1388 if (note->n_type != ABI_NOTETYPE &&
1389 note->n_type != CRT_NOINIT_NOTETYPE)
1391 note_name = (const char *)(note + 1);
1392 if (strncmp(NOTE_VENDOR, note_name, sizeof(NOTE_VENDOR)) != 0)
1394 switch (note->n_type) {
1396 /* DragonFly osrel note */
1397 p = (uintptr_t)(note + 1);
1398 p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
1399 obj->osrel = *(const int32_t *)(p);
1400 dbg("note osrel %d", obj->osrel);
1402 case CRT_NOINIT_NOTETYPE:
1403 /* DragonFly 'crt does not call init' note */
1404 obj->crt_no_init = true;
1405 dbg("note crt_no_init");
1412 dlcheck(void *handle)
1416 for (obj = obj_list; obj != NULL; obj = obj->next)
1417 if (obj == (Obj_Entry *) handle)
1420 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
1421 _rtld_error("Invalid shared object handle %p", handle);
1428 * If the given object is already in the donelist, return true. Otherwise
1429 * add the object to the list and return false.
1432 donelist_check(DoneList *dlp, const Obj_Entry *obj)
1436 for (i = 0; i < dlp->num_used; i++)
1437 if (dlp->objs[i] == obj)
1440 * Our donelist allocation should always be sufficient. But if
1441 * our threads locking isn't working properly, more shared objects
1442 * could have been loaded since we allocated the list. That should
1443 * never happen, but we'll handle it properly just in case it does.
1445 if (dlp->num_used < dlp->num_alloc)
1446 dlp->objs[dlp->num_used++] = obj;
1451 * Hash function for symbol table lookup. Don't even think about changing
1452 * this. It is specified by the System V ABI.
1455 elf_hash(const char *name)
1457 const unsigned char *p = (const unsigned char *) name;
1458 unsigned long h = 0;
1461 while (*p != '\0') {
1462 h = (h << 4) + *p++;
1463 if ((g = h & 0xf0000000) != 0)
1471 * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits
1472 * unsigned in case it's implemented with a wider type.
1474 static uint_fast32_t
1475 gnu_hash(const char *s)
1481 for (c = *s; c != '\0'; c = *++s)
1483 return (h & 0xffffffff);
1487 * Find the library with the given name, and return its full pathname.
1488 * The returned string is dynamically allocated. Generates an error
1489 * message and returns NULL if the library cannot be found.
1491 * If the second argument is non-NULL, then it refers to an already-
1492 * loaded shared object, whose library search path will be searched.
1494 * The search order is:
1495 * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1)
1496 * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1)
1498 * DT_RUNPATH in the referencing file
1499 * ldconfig hints (if -z nodefaultlib, filter out /usr/lib from list)
1500 * /usr/lib _unless_ the referencing file is linked with -z nodefaultlib
1502 * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined.
1505 find_library(const char *xname, const Obj_Entry *refobj)
1509 bool nodeflib, objgiven;
1511 objgiven = refobj != NULL;
1512 if (strchr(xname, '/') != NULL) { /* Hard coded pathname */
1513 if (xname[0] != '/' && !trust) {
1514 _rtld_error("Absolute pathname required for shared object \"%s\"",
1518 if (objgiven && refobj->z_origin) {
1519 return (origin_subst(__DECONST(char *, xname),
1520 refobj->origin_path));
1522 return (xstrdup(xname));
1526 if (libmap_disable || !objgiven ||
1527 (name = lm_find(refobj->path, xname)) == NULL)
1528 name = (char *)xname;
1530 dbg(" Searching for \"%s\"", name);
1532 nodeflib = objgiven ? refobj->z_nodeflib : false;
1534 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
1535 (objgiven && refobj->runpath == NULL && refobj != obj_main &&
1536 (pathname = search_library_path(name, obj_main->rpath)) != NULL) ||
1537 (pathname = search_library_path(name, ld_library_path)) != NULL ||
1539 (pathname = search_library_path(name, refobj->runpath)) != NULL) ||
1540 (pathname = search_library_path(name, gethints(nodeflib))) != NULL ||
1541 (objgiven && !nodeflib &&
1542 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL))
1545 if (objgiven && refobj->path != NULL) {
1546 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
1547 name, basename(refobj->path));
1549 _rtld_error("Shared object \"%s\" not found", name);
1555 * Given a symbol number in a referencing object, find the corresponding
1556 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1557 * no definition was found. Returns a pointer to the Obj_Entry of the
1558 * defining object via the reference parameter DEFOBJ_OUT.
1561 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
1562 const Obj_Entry **defobj_out, int flags, SymCache *cache,
1563 RtldLockState *lockstate)
1567 const Obj_Entry *defobj;
1573 * If we have already found this symbol, get the information from
1576 if (symnum >= refobj->dynsymcount)
1577 return NULL; /* Bad object */
1578 if (cache != NULL && cache[symnum].sym != NULL) {
1579 *defobj_out = cache[symnum].obj;
1580 return cache[symnum].sym;
1583 ref = refobj->symtab + symnum;
1584 name = refobj->strtab + ref->st_name;
1589 * We don't have to do a full scale lookup if the symbol is local.
1590 * We know it will bind to the instance in this load module; to
1591 * which we already have a pointer (ie ref). By not doing a lookup,
1592 * we not only improve performance, but it also avoids unresolvable
1593 * symbols when local symbols are not in the hash table.
1595 * This might occur for TLS module relocations, which simply use
1598 if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) {
1599 if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) {
1600 _rtld_error("%s: Bogus symbol table entry %lu", refobj->path,
1603 symlook_init(&req, name);
1605 req.ventry = fetch_ventry(refobj, symnum);
1606 req.lockstate = lockstate;
1607 res = symlook_default(&req, refobj);
1610 defobj = req.defobj_out;
1618 * If we found no definition and the reference is weak, treat the
1619 * symbol as having the value zero.
1621 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
1627 *defobj_out = defobj;
1628 /* Record the information in the cache to avoid subsequent lookups. */
1629 if (cache != NULL) {
1630 cache[symnum].sym = def;
1631 cache[symnum].obj = defobj;
1634 if (refobj != &obj_rtld)
1635 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
1641 * Return the search path from the ldconfig hints file, reading it if
1642 * necessary. If nostdlib is true, then the default search paths are
1643 * not added to result.
1645 * Returns NULL if there are problems with the hints file,
1646 * or if the search path there is empty.
1649 gethints(bool nostdlib)
1651 static char *hints, *filtered_path;
1652 struct elfhints_hdr hdr;
1653 struct fill_search_info_args sargs, hargs;
1654 struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo;
1655 struct dl_serpath *SLPpath, *hintpath;
1657 unsigned int SLPndx, hintndx, fndx, fcount;
1662 /* First call, read the hints file */
1663 if (hints == NULL) {
1664 /* Keep from trying again in case the hints file is bad. */
1667 if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1)
1669 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1670 hdr.magic != ELFHINTS_MAGIC ||
1675 p = xmalloc(hdr.dirlistlen + 1);
1676 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1677 read(fd, p, hdr.dirlistlen + 1) !=
1678 (ssize_t)hdr.dirlistlen + 1) {
1688 * If caller agreed to receive list which includes the default
1689 * paths, we are done. Otherwise, if we still have not
1690 * calculated filtered result, do it now.
1693 return (hints[0] != '\0' ? hints : NULL);
1694 if (filtered_path != NULL)
1698 * Obtain the list of all configured search paths, and the
1699 * list of the default paths.
1701 * First estimate the size of the results.
1703 smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1705 hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
1708 sargs.request = RTLD_DI_SERINFOSIZE;
1709 sargs.serinfo = &smeta;
1710 hargs.request = RTLD_DI_SERINFOSIZE;
1711 hargs.serinfo = &hmeta;
1713 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1714 path_enumerate(p, fill_search_info, &hargs);
1716 SLPinfo = xmalloc(smeta.dls_size);
1717 hintinfo = xmalloc(hmeta.dls_size);
1720 * Next fetch both sets of paths.
1722 sargs.request = RTLD_DI_SERINFO;
1723 sargs.serinfo = SLPinfo;
1724 sargs.serpath = &SLPinfo->dls_serpath[0];
1725 sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt];
1727 hargs.request = RTLD_DI_SERINFO;
1728 hargs.serinfo = hintinfo;
1729 hargs.serpath = &hintinfo->dls_serpath[0];
1730 hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt];
1732 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &sargs);
1733 path_enumerate(p, fill_search_info, &hargs);
1736 * Now calculate the difference between two sets, by excluding
1737 * standard paths from the full set.
1741 filtered_path = xmalloc(hdr.dirlistlen + 1);
1742 hintpath = &hintinfo->dls_serpath[0];
1743 for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) {
1745 SLPpath = &SLPinfo->dls_serpath[0];
1747 * Check each standard path against current.
1749 for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) {
1750 /* matched, skip the path */
1751 if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) {
1759 * Not matched against any standard path, add the path
1760 * to result. Separate consecutive paths with ':'.
1763 filtered_path[fndx] = ':';
1767 flen = strlen(hintpath->dls_name);
1768 strncpy((filtered_path + fndx), hintpath->dls_name, flen);
1771 filtered_path[fndx] = '\0';
1777 return (filtered_path[0] != '\0' ? filtered_path : NULL);
1781 init_dag(Obj_Entry *root)
1783 const Needed_Entry *needed;
1784 const Objlist_Entry *elm;
1787 if (root->dag_inited)
1789 donelist_init(&donelist);
1791 /* Root object belongs to own DAG. */
1792 objlist_push_tail(&root->dldags, root);
1793 objlist_push_tail(&root->dagmembers, root);
1794 donelist_check(&donelist, root);
1797 * Add dependencies of root object to DAG in breadth order
1798 * by exploiting the fact that each new object get added
1799 * to the tail of the dagmembers list.
1801 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1802 for (needed = elm->obj->needed; needed != NULL; needed = needed->next) {
1803 if (needed->obj == NULL || donelist_check(&donelist, needed->obj))
1805 objlist_push_tail(&needed->obj->dldags, root);
1806 objlist_push_tail(&root->dagmembers, needed->obj);
1809 root->dag_inited = true;
1813 process_nodelete(Obj_Entry *root)
1815 const Objlist_Entry *elm;
1818 * Walk over object DAG and process every dependent object that
1819 * is marked as DF_1_NODELETE. They need to grow their own DAG,
1820 * which then should have its reference upped separately.
1822 STAILQ_FOREACH(elm, &root->dagmembers, link) {
1823 if (elm->obj != NULL && elm->obj->z_nodelete &&
1824 !elm->obj->ref_nodel) {
1825 dbg("obj %s nodelete", elm->obj->path);
1828 elm->obj->ref_nodel = true;
1834 * Initialize the dynamic linker. The argument is the address at which
1835 * the dynamic linker has been mapped into memory. The primary task of
1836 * this function is to relocate the dynamic linker.
1839 init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info)
1841 Obj_Entry objtmp; /* Temporary rtld object */
1842 const Elf_Dyn *dyn_rpath;
1843 const Elf_Dyn *dyn_soname;
1844 const Elf_Dyn *dyn_runpath;
1847 * Conjure up an Obj_Entry structure for the dynamic linker.
1849 * The "path" member can't be initialized yet because string constants
1850 * cannot yet be accessed. Below we will set it correctly.
1852 memset(&objtmp, 0, sizeof(objtmp));
1855 objtmp.mapbase = mapbase;
1857 objtmp.relocbase = mapbase;
1859 if (RTLD_IS_DYNAMIC()) {
1860 objtmp.dynamic = rtld_dynamic(&objtmp);
1861 digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath);
1862 assert(objtmp.needed == NULL);
1863 assert(!objtmp.textrel);
1866 * Temporarily put the dynamic linker entry into the object list, so
1867 * that symbols can be found.
1870 relocate_objects(&objtmp, true, &objtmp, 0, NULL);
1873 /* Initialize the object list. */
1874 obj_tail = &obj_list;
1876 /* Now that non-local variables can be accesses, copy out obj_rtld. */
1877 memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld));
1879 #ifdef ENABLE_OSRELDATE
1880 if (aux_info[AT_OSRELDATE] != NULL)
1881 osreldate = aux_info[AT_OSRELDATE]->a_un.a_val;
1884 digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath);
1886 /* Replace the path with a dynamically allocated copy. */
1887 obj_rtld.path = xstrdup(PATH_RTLD);
1889 r_debug.r_brk = r_debug_state;
1890 r_debug.r_state = RT_CONSISTENT;
1894 * Add the init functions from a needed object list (and its recursive
1895 * needed objects) to "list". This is not used directly; it is a helper
1896 * function for initlist_add_objects(). The write lock must be held
1897 * when this function is called.
1900 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1902 /* Recursively process the successor needed objects. */
1903 if (needed->next != NULL)
1904 initlist_add_neededs(needed->next, list);
1906 /* Process the current needed object. */
1907 if (needed->obj != NULL)
1908 initlist_add_objects(needed->obj, &needed->obj->next, list);
1912 * Scan all of the DAGs rooted in the range of objects from "obj" to
1913 * "tail" and add their init functions to "list". This recurses over
1914 * the DAGs and ensure the proper init ordering such that each object's
1915 * needed libraries are initialized before the object itself. At the
1916 * same time, this function adds the objects to the global finalization
1917 * list "list_fini" in the opposite order. The write lock must be
1918 * held when this function is called.
1921 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1924 if (obj->init_scanned || obj->init_done)
1926 obj->init_scanned = true;
1928 /* Recursively process the successor objects. */
1929 if (&obj->next != tail)
1930 initlist_add_objects(obj->next, tail, list);
1932 /* Recursively process the needed objects. */
1933 if (obj->needed != NULL)
1934 initlist_add_neededs(obj->needed, list);
1935 if (obj->needed_filtees != NULL)
1936 initlist_add_neededs(obj->needed_filtees, list);
1937 if (obj->needed_aux_filtees != NULL)
1938 initlist_add_neededs(obj->needed_aux_filtees, list);
1940 /* Add the object to the init list. */
1941 if (obj->preinit_array != (Elf_Addr)NULL || obj->init != (Elf_Addr)NULL ||
1942 obj->init_array != (Elf_Addr)NULL)
1943 objlist_push_tail(list, obj);
1945 /* Add the object to the global fini list in the reverse order. */
1946 if ((obj->fini != (Elf_Addr)NULL || obj->fini_array != (Elf_Addr)NULL)
1947 && !obj->on_fini_list) {
1948 objlist_push_head(&list_fini, obj);
1949 obj->on_fini_list = true;
1954 #define FPTR_TARGET(f) ((Elf_Addr) (f))
1958 free_needed_filtees(Needed_Entry *n)
1960 Needed_Entry *needed, *needed1;
1962 for (needed = n; needed != NULL; needed = needed->next) {
1963 if (needed->obj != NULL) {
1964 dlclose(needed->obj);
1968 for (needed = n; needed != NULL; needed = needed1) {
1969 needed1 = needed->next;
1975 unload_filtees(Obj_Entry *obj)
1978 free_needed_filtees(obj->needed_filtees);
1979 obj->needed_filtees = NULL;
1980 free_needed_filtees(obj->needed_aux_filtees);
1981 obj->needed_aux_filtees = NULL;
1982 obj->filtees_loaded = false;
1986 load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags,
1987 RtldLockState *lockstate)
1990 for (; needed != NULL; needed = needed->next) {
1991 needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj,
1992 flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) |
1993 RTLD_LOCAL, lockstate);
1998 load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate)
2001 lock_restart_for_upgrade(lockstate);
2002 if (!obj->filtees_loaded) {
2003 load_filtee1(obj, obj->needed_filtees, flags, lockstate);
2004 load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate);
2005 obj->filtees_loaded = true;
2010 process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags)
2014 for (; needed != NULL; needed = needed->next) {
2015 obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj,
2016 flags & ~RTLD_LO_NOLOAD);
2017 if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0)
2024 * Given a shared object, traverse its list of needed objects, and load
2025 * each of them. Returns 0 on success. Generates an error message and
2026 * returns -1 on failure.
2029 load_needed_objects(Obj_Entry *first, int flags)
2033 for (obj = first; obj != NULL; obj = obj->next) {
2034 if (process_needed(obj, obj->needed, flags) == -1)
2041 load_preload_objects(void)
2043 char *p = ld_preload;
2045 static const char delim[] = " \t:;";
2050 p += strspn(p, delim);
2051 while (*p != '\0') {
2052 size_t len = strcspn(p, delim);
2059 obj = load_object(p, -1, NULL, 0);
2061 return -1; /* XXX - cleanup */
2062 obj->z_interpose = true;
2065 p += strspn(p, delim);
2067 /* Check for the magic tracing function */
2068 symlook_init(&req, RTLD_FUNCTRACE);
2069 res = symlook_obj(&req, obj);
2071 rtld_functrace = (void *)(req.defobj_out->relocbase +
2072 req.sym_out->st_value);
2073 rtld_functrace_obj = req.defobj_out;
2076 LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL);
2081 printable_path(const char *path)
2084 return (path == NULL ? "<unknown>" : path);
2088 * Load a shared object into memory, if it is not already loaded. The
2089 * object may be specified by name or by user-supplied file descriptor
2090 * fd_u. In the later case, the fd_u descriptor is not closed, but its
2093 * Returns a pointer to the Obj_Entry for the object. Returns NULL
2097 load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags)
2105 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
2106 if (object_match_name(obj, name))
2110 path = find_library(name, refobj);
2117 * If we didn't find a match by pathname, or the name is not
2118 * supplied, open the file and check again by device and inode.
2119 * This avoids false mismatches caused by multiple links or ".."
2122 * To avoid a race, we open the file and use fstat() rather than
2127 if ((fd = open(path, O_RDONLY | O_CLOEXEC)) == -1) {
2128 _rtld_error("Cannot open \"%s\"", path);
2133 fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0);
2136 * Temporary, remove at 3.6 branch
2137 * User might not have latest kernel installed
2138 * so fall back to old command for a while
2141 if (fd == -1 || (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)) {
2142 _rtld_error("Cannot dup fd");
2148 if (fstat(fd, &sb) == -1) {
2149 _rtld_error("Cannot fstat \"%s\"", printable_path(path));
2154 for (obj = obj_list->next; obj != NULL; obj = obj->next)
2155 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev)
2157 if (obj != NULL && name != NULL) {
2158 object_add_name(obj, name);
2163 if (flags & RTLD_LO_NOLOAD) {
2169 /* First use of this object, so we must map it in */
2170 obj = do_load_object(fd, name, path, &sb, flags);
2179 do_load_object(int fd, const char *name, char *path, struct stat *sbp,
2186 * but first, make sure that environment variables haven't been
2187 * used to circumvent the noexec flag on a filesystem.
2189 if (dangerous_ld_env) {
2190 if (fstatfs(fd, &fs) != 0) {
2191 _rtld_error("Cannot fstatfs \"%s\"", printable_path(path));
2194 if (fs.f_flags & MNT_NOEXEC) {
2195 _rtld_error("Cannot execute objects on %s\n", fs.f_mntonname);
2199 dbg("loading \"%s\"", printable_path(path));
2200 obj = map_object(fd, printable_path(path), sbp);
2205 * If DT_SONAME is present in the object, digest_dynamic2 already
2206 * added it to the object names.
2209 object_add_name(obj, name);
2211 digest_dynamic(obj, 0);
2212 dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
2213 obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
2214 if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
2216 dbg("refusing to load non-loadable \"%s\"", obj->path);
2217 _rtld_error("Cannot dlopen non-loadable %s", obj->path);
2218 munmap(obj->mapbase, obj->mapsize);
2224 obj_tail = &obj->next;
2227 linkmap_add(obj); /* for GDB & dlinfo() */
2228 max_stack_flags |= obj->stack_flags;
2230 dbg(" %p .. %p: %s", obj->mapbase,
2231 obj->mapbase + obj->mapsize - 1, obj->path);
2233 dbg(" WARNING: %s has impure text", obj->path);
2234 LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
2241 obj_from_addr(const void *addr)
2245 for (obj = obj_list; obj != NULL; obj = obj->next) {
2246 if (addr < (void *) obj->mapbase)
2248 if (addr < (void *) (obj->mapbase + obj->mapsize))
2255 * If the main program is defined with a .preinit_array section, call
2256 * each function in order. This must occur before the initialization
2257 * of any shared object or the main program.
2262 Elf_Addr *preinit_addr;
2265 preinit_addr = (Elf_Addr *)obj_main->preinit_array;
2266 if (preinit_addr == NULL)
2269 for (index = 0; index < obj_main->preinit_array_num; index++) {
2270 if (preinit_addr[index] != 0 && preinit_addr[index] != 1) {
2271 dbg("calling preinit function for %s at %p", obj_main->path,
2272 (void *)preinit_addr[index]);
2273 LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index],
2274 0, 0, obj_main->path);
2275 call_init_pointer(obj_main, preinit_addr[index]);
2281 * Call the finalization functions for each of the objects in "list"
2282 * belonging to the DAG of "root" and referenced once. If NULL "root"
2283 * is specified, every finalization function will be called regardless
2284 * of the reference count and the list elements won't be freed. All of
2285 * the objects are expected to have non-NULL fini functions.
2288 objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate)
2292 Elf_Addr *fini_addr;
2295 assert(root == NULL || root->refcount == 1);
2298 * Preserve the current error message since a fini function might
2299 * call into the dynamic linker and overwrite it.
2301 saved_msg = errmsg_save();
2303 STAILQ_FOREACH(elm, list, link) {
2304 if (root != NULL && (elm->obj->refcount != 1 ||
2305 objlist_find(&root->dagmembers, elm->obj) == NULL))
2308 /* Remove object from fini list to prevent recursive invocation. */
2309 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2311 * XXX: If a dlopen() call references an object while the
2312 * fini function is in progress, we might end up trying to
2313 * unload the referenced object in dlclose() or the object
2314 * won't be unloaded although its fini function has been
2317 lock_release(rtld_bind_lock, lockstate);
2320 * It is legal to have both DT_FINI and DT_FINI_ARRAY defined. When this
2321 * happens, DT_FINI_ARRAY is processed first, and it is also processed
2322 * backwards. It is possible to encounter DT_FINI_ARRAY elements with
2323 * values of 0 or 1, but they need to be ignored.
2325 fini_addr = (Elf_Addr *)elm->obj->fini_array;
2326 if (fini_addr != NULL && elm->obj->fini_array_num > 0) {
2327 for (index = elm->obj->fini_array_num - 1; index >= 0; index--) {
2328 if (fini_addr[index] != 0 && fini_addr[index] != 1) {
2329 dbg("calling fini array function for %s at %p",
2330 elm->obj->path, (void *)fini_addr[index]);
2331 LD_UTRACE(UTRACE_FINI_CALL, elm->obj,
2332 (void *)fini_addr[index], 0, 0, elm->obj->path);
2333 call_initfini_pointer(elm->obj, fini_addr[index]);
2337 if (elm->obj->fini != (Elf_Addr)NULL) {
2338 dbg("calling fini function for %s at %p", elm->obj->path,
2339 (void *)elm->obj->fini);
2340 LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini,
2341 0, 0, elm->obj->path);
2342 call_initfini_pointer(elm->obj, elm->obj->fini);
2344 wlock_acquire(rtld_bind_lock, lockstate);
2345 /* No need to free anything if process is going down. */
2349 * We must restart the list traversal after every fini call
2350 * because a dlclose() call from the fini function or from
2351 * another thread might have modified the reference counts.
2355 } while (elm != NULL);
2356 errmsg_restore(saved_msg);
2360 * Call the initialization functions for each of the objects in
2361 * "list". All of the objects are expected to have non-NULL init
2365 objlist_call_init(Objlist *list, RtldLockState *lockstate)
2370 Elf_Addr *init_addr;
2374 * Clean init_scanned flag so that objects can be rechecked and
2375 * possibly initialized earlier if any of vectors called below
2376 * cause the change by using dlopen.
2378 for (obj = obj_list; obj != NULL; obj = obj->next)
2379 obj->init_scanned = false;
2382 * Preserve the current error message since an init function might
2383 * call into the dynamic linker and overwrite it.
2385 saved_msg = errmsg_save();
2386 STAILQ_FOREACH(elm, list, link) {
2387 if (elm->obj->init_done) /* Initialized early. */
2391 * Race: other thread might try to use this object before current
2392 * one completes the initilization. Not much can be done here
2393 * without better locking.
2395 elm->obj->init_done = true;
2396 lock_release(rtld_bind_lock, lockstate);
2399 * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. When
2400 * this happens, DT_INIT is processed first. It is possible to
2401 * encounter DT_INIT_ARRAY elements with values of 0 or 1, but they
2402 * need to be ignored.
2404 if (elm->obj->init != (Elf_Addr)NULL) {
2405 dbg("calling init function for %s at %p", elm->obj->path,
2406 (void *)elm->obj->init);
2407 LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init,
2408 0, 0, elm->obj->path);
2409 call_initfini_pointer(elm->obj, elm->obj->init);
2411 init_addr = (Elf_Addr *)elm->obj->init_array;
2412 if (init_addr != NULL) {
2413 for (index = 0; index < elm->obj->init_array_num; index++) {
2414 if (init_addr[index] != 0 && init_addr[index] != 1) {
2415 dbg("calling init array function for %s at %p", elm->obj->path,
2416 (void *)init_addr[index]);
2417 LD_UTRACE(UTRACE_INIT_CALL, elm->obj,
2418 (void *)init_addr[index], 0, 0, elm->obj->path);
2419 call_init_pointer(elm->obj, init_addr[index]);
2423 wlock_acquire(rtld_bind_lock, lockstate);
2425 errmsg_restore(saved_msg);
2429 objlist_clear(Objlist *list)
2433 while (!STAILQ_EMPTY(list)) {
2434 elm = STAILQ_FIRST(list);
2435 STAILQ_REMOVE_HEAD(list, link);
2440 static Objlist_Entry *
2441 objlist_find(Objlist *list, const Obj_Entry *obj)
2445 STAILQ_FOREACH(elm, list, link)
2446 if (elm->obj == obj)
2452 objlist_init(Objlist *list)
2458 objlist_push_head(Objlist *list, Obj_Entry *obj)
2462 elm = NEW(Objlist_Entry);
2464 STAILQ_INSERT_HEAD(list, elm, link);
2468 objlist_push_tail(Objlist *list, Obj_Entry *obj)
2472 elm = NEW(Objlist_Entry);
2474 STAILQ_INSERT_TAIL(list, elm, link);
2478 objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
2480 Objlist_Entry *elm, *listelm;
2482 STAILQ_FOREACH(listelm, list, link) {
2483 if (listelm->obj == listobj)
2486 elm = NEW(Objlist_Entry);
2488 if (listelm != NULL)
2489 STAILQ_INSERT_AFTER(list, listelm, elm, link);
2491 STAILQ_INSERT_TAIL(list, elm, link);
2495 objlist_remove(Objlist *list, Obj_Entry *obj)
2499 if ((elm = objlist_find(list, obj)) != NULL) {
2500 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
2506 * Relocate dag rooted in the specified object.
2507 * Returns 0 on success, or -1 on failure.
2511 relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj,
2512 int flags, RtldLockState *lockstate)
2518 STAILQ_FOREACH(elm, &root->dagmembers, link) {
2519 error = relocate_object(elm->obj, bind_now, rtldobj, flags,
2528 * Relocate single object.
2529 * Returns 0 on success, or -1 on failure.
2532 relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
2533 int flags, RtldLockState *lockstate)
2538 obj->relocated = true;
2540 dbg("relocating \"%s\"", obj->path);
2542 if (obj->symtab == NULL || obj->strtab == NULL ||
2543 !(obj->valid_hash_sysv || obj->valid_hash_gnu)) {
2544 _rtld_error("%s: Shared object has no run-time symbol table",
2550 /* There are relocations to the write-protected text segment. */
2551 if (mprotect(obj->mapbase, obj->textsize,
2552 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
2553 _rtld_error("%s: Cannot write-enable text segment: %s",
2554 obj->path, rtld_strerror(errno));
2559 /* Process the non-PLT relocations. */
2560 if (reloc_non_plt(obj, rtldobj, flags, lockstate))
2564 * Reprotect the text segment. Make sure it is included in the
2565 * core dump since we modified it. This unfortunately causes the
2566 * entire text segment to core-out but we don't have much of a
2567 * choice. We could try to only reenable core dumps on pages
2568 * in which relocations occured but that is likely most of the text
2569 * pages anyway, and even that would not work because the rest of
2570 * the text pages would wind up as a read-only OBJT_DEFAULT object
2571 * (created due to our modifications) backed by the original OBJT_VNODE
2572 * object, and the ELF coredump code is currently only able to dump
2573 * vnode records for pure vnode-backed mappings, not vnode backings
2574 * to memory objects.
2577 madvise(obj->mapbase, obj->textsize, MADV_CORE);
2578 if (mprotect(obj->mapbase, obj->textsize,
2579 PROT_READ|PROT_EXEC) == -1) {
2580 _rtld_error("%s: Cannot write-protect text segment: %s",
2581 obj->path, rtld_strerror(errno));
2587 /* Set the special PLT or GOT entries. */
2590 /* Process the PLT relocations. */
2591 if (reloc_plt(obj) == -1)
2593 /* Relocate the jump slots if we are doing immediate binding. */
2594 if (obj->bind_now || bind_now)
2595 if (reloc_jmpslots(obj, flags, lockstate) == -1)
2599 * Set up the magic number and version in the Obj_Entry. These
2600 * were checked in the crt1.o from the original ElfKit, so we
2601 * set them for backward compatibility.
2603 obj->magic = RTLD_MAGIC;
2604 obj->version = RTLD_VERSION;
2607 * Set relocated data to read-only status if protection specified
2610 if (obj->relro_size) {
2611 if (mprotect(obj->relro_page, obj->relro_size, PROT_READ) == -1) {
2612 _rtld_error("%s: Cannot enforce relro relocation: %s",
2613 obj->path, rtld_strerror(errno));
2621 * Relocate newly-loaded shared objects. The argument is a pointer to
2622 * the Obj_Entry for the first such object. All objects from the first
2623 * to the end of the list of objects are relocated. Returns 0 on success,
2627 relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj,
2628 int flags, RtldLockState *lockstate)
2633 for (error = 0, obj = first; obj != NULL; obj = obj->next) {
2634 error = relocate_object(obj, bind_now, rtldobj, flags,
2643 * The handling of R_MACHINE_IRELATIVE relocations and jumpslots
2644 * referencing STT_GNU_IFUNC symbols is postponed till the other
2645 * relocations are done. The indirect functions specified as
2646 * ifunc are allowed to call other symbols, so we need to have
2647 * objects relocated before asking for resolution from indirects.
2649 * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion,
2650 * instead of the usual lazy handling of PLT slots. It is
2651 * consistent with how GNU does it.
2654 resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags,
2655 RtldLockState *lockstate)
2657 if (obj->irelative && reloc_iresolve(obj, lockstate) == -1)
2659 if ((obj->bind_now || bind_now) && obj->gnu_ifunc &&
2660 reloc_gnu_ifunc(obj, flags, lockstate) == -1)
2666 resolve_objects_ifunc(Obj_Entry *first, bool bind_now, int flags,
2667 RtldLockState *lockstate)
2671 for (obj = first; obj != NULL; obj = obj->next) {
2672 if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1)
2679 initlist_objects_ifunc(Objlist *list, bool bind_now, int flags,
2680 RtldLockState *lockstate)
2684 STAILQ_FOREACH(elm, list, link) {
2685 if (resolve_object_ifunc(elm->obj, bind_now, flags,
2693 * Cleanup procedure. It will be called (by the atexit mechanism) just
2694 * before the process exits.
2699 RtldLockState lockstate;
2701 wlock_acquire(rtld_bind_lock, &lockstate);
2703 objlist_call_fini(&list_fini, NULL, &lockstate);
2704 /* No need to remove the items from the list, since we are exiting. */
2705 if (!libmap_disable)
2707 lock_release(rtld_bind_lock, &lockstate);
2711 * Iterate over a search path, translate each element, and invoke the
2712 * callback on the result.
2715 path_enumerate(const char *path, path_enum_proc callback, void *arg)
2721 path += strspn(path, ":;");
2722 while (*path != '\0') {
2726 len = strcspn(path, ":;");
2727 trans = lm_findn(NULL, path, len);
2729 res = callback(trans, strlen(trans), arg);
2731 res = callback(path, len, arg);
2737 path += strspn(path, ":;");
2743 struct try_library_args {
2751 try_library_path(const char *dir, size_t dirlen, void *param)
2753 struct try_library_args *arg;
2756 if (*dir == '/' || trust) {
2759 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
2762 pathname = arg->buffer;
2763 strncpy(pathname, dir, dirlen);
2764 pathname[dirlen] = '/';
2765 strcpy(pathname + dirlen + 1, arg->name);
2767 dbg(" Trying \"%s\"", pathname);
2768 if (access(pathname, F_OK) == 0) { /* We found it */
2769 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
2770 strcpy(pathname, arg->buffer);
2778 search_library_path(const char *name, const char *path)
2781 struct try_library_args arg;
2787 arg.namelen = strlen(name);
2788 arg.buffer = xmalloc(PATH_MAX);
2789 arg.buflen = PATH_MAX;
2791 p = path_enumerate(path, try_library_path, &arg);
2799 dlclose(void *handle)
2802 RtldLockState lockstate;
2804 wlock_acquire(rtld_bind_lock, &lockstate);
2805 root = dlcheck(handle);
2807 lock_release(rtld_bind_lock, &lockstate);
2810 LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount,
2813 /* Unreference the object and its dependencies. */
2814 root->dl_refcount--;
2816 if (root->refcount == 1) {
2818 * The object will be no longer referenced, so we must unload it.
2819 * First, call the fini functions.
2821 objlist_call_fini(&list_fini, root, &lockstate);
2825 /* Finish cleaning up the newly-unreferenced objects. */
2826 GDB_STATE(RT_DELETE,&root->linkmap);
2827 unload_object(root);
2828 GDB_STATE(RT_CONSISTENT,NULL);
2832 LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL);
2833 lock_release(rtld_bind_lock, &lockstate);
2840 char *msg = error_message;
2841 error_message = NULL;
2846 dlopen(const char *name, int mode)
2849 return (rtld_dlopen(name, -1, mode));
2853 fdlopen(int fd, int mode)
2856 return (rtld_dlopen(NULL, fd, mode));
2860 rtld_dlopen(const char *name, int fd, int mode)
2862 RtldLockState lockstate;
2865 LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name);
2866 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
2867 if (ld_tracing != NULL) {
2868 rlock_acquire(rtld_bind_lock, &lockstate);
2869 if (sigsetjmp(lockstate.env, 0) != 0)
2870 lock_upgrade(rtld_bind_lock, &lockstate);
2871 environ = (char **)*get_program_var_addr("environ", &lockstate);
2872 lock_release(rtld_bind_lock, &lockstate);
2874 lo_flags = RTLD_LO_DLOPEN;
2875 if (mode & RTLD_NODELETE)
2876 lo_flags |= RTLD_LO_NODELETE;
2877 if (mode & RTLD_NOLOAD)
2878 lo_flags |= RTLD_LO_NOLOAD;
2879 if (ld_tracing != NULL)
2880 lo_flags |= RTLD_LO_TRACE;
2882 return (dlopen_object(name, fd, obj_main, lo_flags,
2883 mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL));
2887 dlopen_cleanup(Obj_Entry *obj)
2892 if (obj->refcount == 0)
2897 dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
2898 int mode, RtldLockState *lockstate)
2900 Obj_Entry **old_obj_tail;
2903 RtldLockState mlockstate;
2906 objlist_init(&initlist);
2908 if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) {
2909 wlock_acquire(rtld_bind_lock, &mlockstate);
2910 lockstate = &mlockstate;
2912 GDB_STATE(RT_ADD,NULL);
2914 old_obj_tail = obj_tail;
2916 if (name == NULL && fd == -1) {
2920 obj = load_object(name, fd, refobj, lo_flags);
2925 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
2926 objlist_push_tail(&list_global, obj);
2927 if (*old_obj_tail != NULL) { /* We loaded something new. */
2928 assert(*old_obj_tail == obj);
2929 result = load_needed_objects(obj,
2930 lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY));
2934 result = rtld_verify_versions(&obj->dagmembers);
2935 if (result != -1 && ld_tracing)
2937 if (result == -1 || relocate_object_dag(obj,
2938 (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld,
2939 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2941 dlopen_cleanup(obj);
2943 } else if (lo_flags & RTLD_LO_EARLY) {
2945 * Do not call the init functions for early loaded
2946 * filtees. The image is still not initialized enough
2949 * Our object is found by the global object list and
2950 * will be ordered among all init calls done right
2951 * before transferring control to main.
2954 /* Make list of init functions to call. */
2955 initlist_add_objects(obj, &obj->next, &initlist);
2958 * Process all no_delete objects here, given them own
2959 * DAGs to prevent their dependencies from being unloaded.
2960 * This has to be done after we have loaded all of the
2961 * dependencies, so that we do not miss any.
2964 process_nodelete(obj);
2967 * Bump the reference counts for objects on this DAG. If
2968 * this is the first dlopen() call for the object that was
2969 * already loaded as a dependency, initialize the dag
2975 if ((lo_flags & RTLD_LO_TRACE) != 0)
2978 if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 ||
2979 obj->z_nodelete) && !obj->ref_nodel) {
2980 dbg("obj %s nodelete", obj->path);
2982 obj->z_nodelete = obj->ref_nodel = true;
2986 LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0,
2988 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
2990 if (!(lo_flags & RTLD_LO_EARLY)) {
2991 map_stacks_exec(lockstate);
2994 if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW,
2995 (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0,
2997 objlist_clear(&initlist);
2998 dlopen_cleanup(obj);
2999 if (lockstate == &mlockstate)
3000 lock_release(rtld_bind_lock, lockstate);
3004 if (!(lo_flags & RTLD_LO_EARLY)) {
3005 /* Call the init functions. */
3006 objlist_call_init(&initlist, lockstate);
3008 objlist_clear(&initlist);
3009 if (lockstate == &mlockstate)
3010 lock_release(rtld_bind_lock, lockstate);
3013 trace_loaded_objects(obj);
3014 if (lockstate == &mlockstate)
3015 lock_release(rtld_bind_lock, lockstate);
3020 do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
3024 const Obj_Entry *obj, *defobj;
3027 RtldLockState lockstate;
3033 symlook_init(&req, name);
3035 req.flags = flags | SYMLOOK_IN_PLT;
3036 req.lockstate = &lockstate;
3038 rlock_acquire(rtld_bind_lock, &lockstate);
3039 if (sigsetjmp(lockstate.env, 0) != 0)
3040 lock_upgrade(rtld_bind_lock, &lockstate);
3041 if (handle == NULL || handle == RTLD_NEXT ||
3042 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
3044 if ((obj = obj_from_addr(retaddr)) == NULL) {
3045 _rtld_error("Cannot determine caller's shared object");
3046 lock_release(rtld_bind_lock, &lockstate);
3049 if (handle == NULL) { /* Just the caller's shared object. */
3050 res = symlook_obj(&req, obj);
3053 defobj = req.defobj_out;
3055 } else if (handle == RTLD_NEXT || /* Objects after caller's */
3056 handle == RTLD_SELF) { /* ... caller included */
3057 if (handle == RTLD_NEXT)
3059 for (; obj != NULL; obj = obj->next) {
3060 res = symlook_obj(&req, obj);
3063 ELF_ST_BIND(req.sym_out->st_info) != STB_WEAK) {
3065 defobj = req.defobj_out;
3066 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3072 * Search the dynamic linker itself, and possibly resolve the
3073 * symbol from there. This is how the application links to
3074 * dynamic linker services such as dlopen.
3076 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3077 res = symlook_obj(&req, &obj_rtld);
3080 defobj = req.defobj_out;
3084 assert(handle == RTLD_DEFAULT);
3085 res = symlook_default(&req, obj);
3087 defobj = req.defobj_out;
3092 if ((obj = dlcheck(handle)) == NULL) {
3093 lock_release(rtld_bind_lock, &lockstate);
3097 donelist_init(&donelist);
3098 if (obj->mainprog) {
3099 /* Handle obtained by dlopen(NULL, ...) implies global scope. */
3100 res = symlook_global(&req, &donelist);
3103 defobj = req.defobj_out;
3106 * Search the dynamic linker itself, and possibly resolve the
3107 * symbol from there. This is how the application links to
3108 * dynamic linker services such as dlopen.
3110 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
3111 res = symlook_obj(&req, &obj_rtld);
3114 defobj = req.defobj_out;
3119 /* Search the whole DAG rooted at the given object. */
3120 res = symlook_list(&req, &obj->dagmembers, &donelist);
3123 defobj = req.defobj_out;
3129 lock_release(rtld_bind_lock, &lockstate);
3132 * The value required by the caller is derived from the value
3133 * of the symbol. For the ia64 architecture, we need to
3134 * construct a function descriptor which the caller can use to
3135 * call the function with the right 'gp' value. For other
3136 * architectures and for non-functions, the value is simply
3137 * the relocated value of the symbol.
3139 if (ELF_ST_TYPE(def->st_info) == STT_FUNC)
3140 return (make_function_pointer(def, defobj));
3141 else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC)
3142 return (rtld_resolve_ifunc(defobj, def));
3143 else if (ELF_ST_TYPE(def->st_info) == STT_TLS) {
3144 ti.ti_module = defobj->tlsindex;
3145 ti.ti_offset = def->st_value;
3146 return (__tls_get_addr(&ti));
3148 return (defobj->relocbase + def->st_value);
3151 _rtld_error("Undefined symbol \"%s\"", name);
3152 lock_release(rtld_bind_lock, &lockstate);
3157 dlsym(void *handle, const char *name)
3159 return do_dlsym(handle, name, __builtin_return_address(0), NULL,
3164 dlfunc(void *handle, const char *name)
3171 rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
3177 dlvsym(void *handle, const char *name, const char *version)
3181 ventry.name = version;
3183 ventry.hash = elf_hash(version);
3185 return do_dlsym(handle, name, __builtin_return_address(0), &ventry,
3190 _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info)
3192 const Obj_Entry *obj;
3193 RtldLockState lockstate;
3195 rlock_acquire(rtld_bind_lock, &lockstate);
3196 obj = obj_from_addr(addr);
3198 _rtld_error("No shared object contains address");
3199 lock_release(rtld_bind_lock, &lockstate);
3202 rtld_fill_dl_phdr_info(obj, phdr_info);
3203 lock_release(rtld_bind_lock, &lockstate);
3208 dladdr(const void *addr, Dl_info *info)
3210 const Obj_Entry *obj;
3213 unsigned long symoffset;
3214 RtldLockState lockstate;
3216 rlock_acquire(rtld_bind_lock, &lockstate);
3217 obj = obj_from_addr(addr);
3219 _rtld_error("No shared object contains address");
3220 lock_release(rtld_bind_lock, &lockstate);
3223 info->dli_fname = obj->path;
3224 info->dli_fbase = obj->mapbase;
3225 info->dli_saddr = NULL;
3226 info->dli_sname = NULL;
3229 * Walk the symbol list looking for the symbol whose address is
3230 * closest to the address sent in.
3232 for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) {
3233 def = obj->symtab + symoffset;
3236 * For skip the symbol if st_shndx is either SHN_UNDEF or
3239 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
3243 * If the symbol is greater than the specified address, or if it
3244 * is further away from addr than the current nearest symbol,
3247 symbol_addr = obj->relocbase + def->st_value;
3248 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
3251 /* Update our idea of the nearest symbol. */
3252 info->dli_sname = obj->strtab + def->st_name;
3253 info->dli_saddr = symbol_addr;
3256 if (info->dli_saddr == addr)
3259 lock_release(rtld_bind_lock, &lockstate);
3264 dlinfo(void *handle, int request, void *p)
3266 const Obj_Entry *obj;
3267 RtldLockState lockstate;
3270 rlock_acquire(rtld_bind_lock, &lockstate);
3272 if (handle == NULL || handle == RTLD_SELF) {
3275 retaddr = __builtin_return_address(0); /* __GNUC__ only */
3276 if ((obj = obj_from_addr(retaddr)) == NULL)
3277 _rtld_error("Cannot determine caller's shared object");
3279 obj = dlcheck(handle);
3282 lock_release(rtld_bind_lock, &lockstate);
3288 case RTLD_DI_LINKMAP:
3289 *((struct link_map const **)p) = &obj->linkmap;
3291 case RTLD_DI_ORIGIN:
3292 error = rtld_dirname(obj->path, p);
3295 case RTLD_DI_SERINFOSIZE:
3296 case RTLD_DI_SERINFO:
3297 error = do_search_info(obj, request, (struct dl_serinfo *)p);
3301 _rtld_error("Invalid request %d passed to dlinfo()", request);
3305 lock_release(rtld_bind_lock, &lockstate);
3311 rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info)
3314 phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase;
3315 phdr_info->dlpi_name = STAILQ_FIRST(&obj->names) ?
3316 STAILQ_FIRST(&obj->names)->name : obj->path;
3317 phdr_info->dlpi_phdr = obj->phdr;
3318 phdr_info->dlpi_phnum = obj->phsize / sizeof(obj->phdr[0]);
3319 phdr_info->dlpi_tls_modid = obj->tlsindex;
3320 phdr_info->dlpi_tls_data = obj->tlsinit;
3321 phdr_info->dlpi_adds = obj_loads;
3322 phdr_info->dlpi_subs = obj_loads - obj_count;
3326 dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param)
3328 struct dl_phdr_info phdr_info;
3329 const Obj_Entry *obj;
3330 RtldLockState bind_lockstate, phdr_lockstate;
3333 wlock_acquire(rtld_phdr_lock, &phdr_lockstate);
3334 rlock_acquire(rtld_bind_lock, &bind_lockstate);
3338 for (obj = obj_list; obj != NULL; obj = obj->next) {
3339 rtld_fill_dl_phdr_info(obj, &phdr_info);
3340 if ((error = callback(&phdr_info, sizeof phdr_info, param)) != 0)
3345 rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info);
3346 error = callback(&phdr_info, sizeof(phdr_info), param);
3349 lock_release(rtld_bind_lock, &bind_lockstate);
3350 lock_release(rtld_phdr_lock, &phdr_lockstate);
3356 fill_search_info(const char *dir, size_t dirlen, void *param)
3358 struct fill_search_info_args *arg;
3362 if (arg->request == RTLD_DI_SERINFOSIZE) {
3363 arg->serinfo->dls_cnt ++;
3364 arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1;
3366 struct dl_serpath *s_entry;
3368 s_entry = arg->serpath;
3369 s_entry->dls_name = arg->strspace;
3370 s_entry->dls_flags = arg->flags;
3372 strncpy(arg->strspace, dir, dirlen);
3373 arg->strspace[dirlen] = '\0';
3375 arg->strspace += dirlen + 1;
3383 do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
3385 struct dl_serinfo _info;
3386 struct fill_search_info_args args;
3388 args.request = RTLD_DI_SERINFOSIZE;
3389 args.serinfo = &_info;
3391 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
3394 path_enumerate(obj->rpath, fill_search_info, &args);
3395 path_enumerate(ld_library_path, fill_search_info, &args);
3396 path_enumerate(obj->runpath, fill_search_info, &args);
3397 path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args);
3398 if (!obj->z_nodeflib)
3399 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
3402 if (request == RTLD_DI_SERINFOSIZE) {
3403 info->dls_size = _info.dls_size;
3404 info->dls_cnt = _info.dls_cnt;
3408 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
3409 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
3413 args.request = RTLD_DI_SERINFO;
3414 args.serinfo = info;
3415 args.serpath = &info->dls_serpath[0];
3416 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
3418 args.flags = LA_SER_RUNPATH;
3419 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
3422 args.flags = LA_SER_LIBPATH;
3423 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
3426 args.flags = LA_SER_RUNPATH;
3427 if (path_enumerate(obj->runpath, fill_search_info, &args) != NULL)
3430 args.flags = LA_SER_CONFIG;
3431 if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, &args)
3435 args.flags = LA_SER_DEFAULT;
3436 if (!obj->z_nodeflib &&
3437 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
3443 rtld_dirname(const char *path, char *bname)
3447 /* Empty or NULL string gets treated as "." */
3448 if (path == NULL || *path == '\0') {
3454 /* Strip trailing slashes */
3455 endp = path + strlen(path) - 1;
3456 while (endp > path && *endp == '/')
3459 /* Find the start of the dir */
3460 while (endp > path && *endp != '/')
3463 /* Either the dir is "/" or there are no slashes */
3465 bname[0] = *endp == '/' ? '/' : '.';
3471 } while (endp > path && *endp == '/');
3474 if (endp - path + 2 > PATH_MAX)
3476 _rtld_error("Filename is too long: %s", path);
3480 strncpy(bname, path, endp - path + 1);
3481 bname[endp - path + 1] = '\0';
3486 rtld_dirname_abs(const char *path, char *base)
3488 char base_rel[PATH_MAX];
3490 if (rtld_dirname(path, base) == -1)
3494 if (getcwd(base_rel, sizeof(base_rel)) == NULL ||
3495 strlcat(base_rel, "/", sizeof(base_rel)) >= sizeof(base_rel) ||
3496 strlcat(base_rel, base, sizeof(base_rel)) >= sizeof(base_rel))
3498 strcpy(base, base_rel);
3503 linkmap_add(Obj_Entry *obj)
3505 struct link_map *l = &obj->linkmap;
3506 struct link_map *prev;
3508 obj->linkmap.l_name = obj->path;
3509 obj->linkmap.l_addr = obj->mapbase;
3510 obj->linkmap.l_ld = obj->dynamic;
3512 /* GDB needs load offset on MIPS to use the symbols */
3513 obj->linkmap.l_offs = obj->relocbase;
3516 if (r_debug.r_map == NULL) {
3522 * Scan to the end of the list, but not past the entry for the
3523 * dynamic linker, which we want to keep at the very end.
3525 for (prev = r_debug.r_map;
3526 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
3527 prev = prev->l_next)
3530 /* Link in the new entry. */
3532 l->l_next = prev->l_next;
3533 if (l->l_next != NULL)
3534 l->l_next->l_prev = l;
3539 linkmap_delete(Obj_Entry *obj)
3541 struct link_map *l = &obj->linkmap;
3543 if (l->l_prev == NULL) {
3544 if ((r_debug.r_map = l->l_next) != NULL)
3545 l->l_next->l_prev = NULL;
3549 if ((l->l_prev->l_next = l->l_next) != NULL)
3550 l->l_next->l_prev = l->l_prev;
3554 * Function for the debugger to set a breakpoint on to gain control.
3556 * The two parameters allow the debugger to easily find and determine
3557 * what the runtime loader is doing and to whom it is doing it.
3559 * When the loadhook trap is hit (r_debug_state, set at program
3560 * initialization), the arguments can be found on the stack:
3562 * +8 struct link_map *m
3563 * +4 struct r_debug *rd
3567 r_debug_state(struct r_debug* rd, struct link_map *m)
3570 * The following is a hack to force the compiler to emit calls to
3571 * this function, even when optimizing. If the function is empty,
3572 * the compiler is not obliged to emit any code for calls to it,
3573 * even when marked __noinline. However, gdb depends on those
3576 __asm __volatile("" : : : "memory");
3580 * Get address of the pointer variable in the main program.
3581 * Prefer non-weak symbol over the weak one.
3583 static const void **
3584 get_program_var_addr(const char *name, RtldLockState *lockstate)
3589 symlook_init(&req, name);
3590 req.lockstate = lockstate;
3591 donelist_init(&donelist);
3592 if (symlook_global(&req, &donelist) != 0)
3594 if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC)
3595 return ((const void **)make_function_pointer(req.sym_out,
3597 else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC)
3598 return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out));
3600 return ((const void **)(req.defobj_out->relocbase +
3601 req.sym_out->st_value));
3605 * Set a pointer variable in the main program to the given value. This
3606 * is used to set key variables such as "environ" before any of the
3607 * init functions are called.
3610 set_program_var(const char *name, const void *value)
3614 if ((addr = get_program_var_addr(name, NULL)) != NULL) {
3615 dbg("\"%s\": *%p <-- %p", name, addr, value);
3621 * Search the global objects, including dependencies and main object,
3622 * for the given symbol.
3625 symlook_global(SymLook *req, DoneList *donelist)
3628 const Objlist_Entry *elm;
3631 symlook_init_from_req(&req1, req);
3633 /* Search all objects loaded at program start up. */
3634 if (req->defobj_out == NULL ||
3635 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3636 res = symlook_list(&req1, &list_main, donelist);
3637 if (res == 0 && (req->defobj_out == NULL ||
3638 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3639 req->sym_out = req1.sym_out;
3640 req->defobj_out = req1.defobj_out;
3641 assert(req->defobj_out != NULL);
3645 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
3646 STAILQ_FOREACH(elm, &list_global, link) {
3647 if (req->defobj_out != NULL &&
3648 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3650 res = symlook_list(&req1, &elm->obj->dagmembers, donelist);
3651 if (res == 0 && (req->defobj_out == NULL ||
3652 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3653 req->sym_out = req1.sym_out;
3654 req->defobj_out = req1.defobj_out;
3655 assert(req->defobj_out != NULL);
3659 return (req->sym_out != NULL ? 0 : ESRCH);
3663 * This is a special version of getenv which is far more efficient
3664 * at finding LD_ environment vars.
3668 _getenv_ld(const char *id)
3672 int idlen = strlen(id);
3674 if (ld_index == LD_ARY_CACHE)
3676 if (ld_index == 0) {
3677 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) {
3678 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_')
3685 for (i = ld_index - 1; i >= 0; --i) {
3686 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=')
3687 return(ld_ary[i] + idlen + 1);
3693 * Given a symbol name in a referencing object, find the corresponding
3694 * definition of the symbol. Returns a pointer to the symbol, or NULL if
3695 * no definition was found. Returns a pointer to the Obj_Entry of the
3696 * defining object via the reference parameter DEFOBJ_OUT.
3699 symlook_default(SymLook *req, const Obj_Entry *refobj)
3702 const Objlist_Entry *elm;
3706 donelist_init(&donelist);
3707 symlook_init_from_req(&req1, req);
3709 /* Look first in the referencing object if linked symbolically. */
3710 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
3711 res = symlook_obj(&req1, refobj);
3713 req->sym_out = req1.sym_out;
3714 req->defobj_out = req1.defobj_out;
3715 assert(req->defobj_out != NULL);
3719 symlook_global(req, &donelist);
3721 /* Search all dlopened DAGs containing the referencing object. */
3722 STAILQ_FOREACH(elm, &refobj->dldags, link) {
3723 if (req->sym_out != NULL &&
3724 ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)
3726 res = symlook_list(&req1, &elm->obj->dagmembers, &donelist);
3727 if (res == 0 && (req->sym_out == NULL ||
3728 ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) {
3729 req->sym_out = req1.sym_out;
3730 req->defobj_out = req1.defobj_out;
3731 assert(req->defobj_out != NULL);
3736 * Search the dynamic linker itself, and possibly resolve the
3737 * symbol from there. This is how the application links to
3738 * dynamic linker services such as dlopen.
3740 if (req->sym_out == NULL ||
3741 ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) {
3742 res = symlook_obj(&req1, &obj_rtld);
3744 req->sym_out = req1.sym_out;
3745 req->defobj_out = req1.defobj_out;
3746 assert(req->defobj_out != NULL);
3750 return (req->sym_out != NULL ? 0 : ESRCH);
3754 symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp)
3757 const Obj_Entry *defobj;
3758 const Objlist_Entry *elm;
3764 STAILQ_FOREACH(elm, objlist, link) {
3765 if (donelist_check(dlp, elm->obj))
3767 symlook_init_from_req(&req1, req);
3768 if ((res = symlook_obj(&req1, elm->obj)) == 0) {
3769 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3771 defobj = req1.defobj_out;
3772 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3779 req->defobj_out = defobj;
3786 * Search the chain of DAGS cointed to by the given Needed_Entry
3787 * for a symbol of the given name. Each DAG is scanned completely
3788 * before advancing to the next one. Returns a pointer to the symbol,
3789 * or NULL if no definition was found.
3792 symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp)
3795 const Needed_Entry *n;
3796 const Obj_Entry *defobj;
3802 symlook_init_from_req(&req1, req);
3803 for (n = needed; n != NULL; n = n->next) {
3804 if (n->obj == NULL ||
3805 (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0)
3807 if (def == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK) {
3809 defobj = req1.defobj_out;
3810 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
3816 req->defobj_out = defobj;
3823 * Search the symbol table of a single shared object for a symbol of
3824 * the given name and version, if requested. Returns a pointer to the
3825 * symbol, or NULL if no definition was found. If the object is
3826 * filter, return filtered symbol from filtee.
3828 * The symbol's hash value is passed in for efficiency reasons; that
3829 * eliminates many recomputations of the hash value.
3832 symlook_obj(SymLook *req, const Obj_Entry *obj)
3836 int flags, res, mres;
3839 * If there is at least one valid hash at this point, we prefer to
3840 * use the faster GNU version if available.
3842 if (obj->valid_hash_gnu)
3843 mres = symlook_obj1_gnu(req, obj);
3844 else if (obj->valid_hash_sysv)
3845 mres = symlook_obj1_sysv(req, obj);
3850 if (obj->needed_filtees != NULL) {
3851 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3852 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3853 donelist_init(&donelist);
3854 symlook_init_from_req(&req1, req);
3855 res = symlook_needed(&req1, obj->needed_filtees, &donelist);
3857 req->sym_out = req1.sym_out;
3858 req->defobj_out = req1.defobj_out;
3862 if (obj->needed_aux_filtees != NULL) {
3863 flags = (req->flags & SYMLOOK_EARLY) ? RTLD_LO_EARLY : 0;
3864 load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate);
3865 donelist_init(&donelist);
3866 symlook_init_from_req(&req1, req);
3867 res = symlook_needed(&req1, obj->needed_aux_filtees, &donelist);
3869 req->sym_out = req1.sym_out;
3870 req->defobj_out = req1.defobj_out;
3878 /* Symbol match routine common to both hash functions */
3880 matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result,
3881 const unsigned long symnum)
3884 const Elf_Sym *symp;
3887 symp = obj->symtab + symnum;
3888 strp = obj->strtab + symp->st_name;
3890 switch (ELF_ST_TYPE(symp->st_info)) {
3896 if (symp->st_value == 0)
3900 if (symp->st_shndx != SHN_UNDEF)
3902 else if (((req->flags & SYMLOOK_IN_PLT) == 0) &&
3903 (ELF_ST_TYPE(symp->st_info) == STT_FUNC))
3909 if (strcmp(req->name, strp) != 0)
3912 if (req->ventry == NULL) {
3913 if (obj->versyms != NULL) {
3914 verndx = VER_NDX(obj->versyms[symnum]);
3915 if (verndx > obj->vernum) {
3917 "%s: symbol %s references wrong version %d",
3918 obj->path, obj->strtab + symnum, verndx);
3922 * If we are not called from dlsym (i.e. this
3923 * is a normal relocation from unversioned
3924 * binary), accept the symbol immediately if
3925 * it happens to have first version after this
3926 * shared object became versioned. Otherwise,
3927 * if symbol is versioned and not hidden,
3928 * remember it. If it is the only symbol with
3929 * this name exported by the shared object, it
3930 * will be returned as a match by the calling
3931 * function. If symbol is global (verndx < 2)
3932 * accept it unconditionally.
3934 if ((req->flags & SYMLOOK_DLSYM) == 0 &&
3935 verndx == VER_NDX_GIVEN) {
3936 result->sym_out = symp;
3939 else if (verndx >= VER_NDX_GIVEN) {
3940 if ((obj->versyms[symnum] & VER_NDX_HIDDEN)
3942 if (result->vsymp == NULL)
3943 result->vsymp = symp;
3949 result->sym_out = symp;
3952 if (obj->versyms == NULL) {
3953 if (object_match_name(obj, req->ventry->name)) {
3954 _rtld_error("%s: object %s should provide version %s "
3955 "for symbol %s", obj_rtld.path, obj->path,
3956 req->ventry->name, obj->strtab + symnum);
3960 verndx = VER_NDX(obj->versyms[symnum]);
3961 if (verndx > obj->vernum) {
3962 _rtld_error("%s: symbol %s references wrong version %d",
3963 obj->path, obj->strtab + symnum, verndx);
3966 if (obj->vertab[verndx].hash != req->ventry->hash ||
3967 strcmp(obj->vertab[verndx].name, req->ventry->name)) {
3969 * Version does not match. Look if this is a
3970 * global symbol and if it is not hidden. If
3971 * global symbol (verndx < 2) is available,
3972 * use it. Do not return symbol if we are
3973 * called by dlvsym, because dlvsym looks for
3974 * a specific version and default one is not
3975 * what dlvsym wants.
3977 if ((req->flags & SYMLOOK_DLSYM) ||
3978 (verndx >= VER_NDX_GIVEN) ||
3979 (obj->versyms[symnum] & VER_NDX_HIDDEN))
3983 result->sym_out = symp;
3988 * Search for symbol using SysV hash function.
3989 * obj->buckets is known not to be NULL at this point; the test for this was
3990 * performed with the obj->valid_hash_sysv assignment.
3993 symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj)
3995 unsigned long symnum;
3996 Sym_Match_Result matchres;
3998 matchres.sym_out = NULL;
3999 matchres.vsymp = NULL;
4000 matchres.vcount = 0;
4002 for (symnum = obj->buckets[req->hash % obj->nbuckets];
4003 symnum != STN_UNDEF; symnum = obj->chains[symnum]) {
4004 if (symnum >= obj->nchains)
4005 return (ESRCH); /* Bad object */
4007 if (matched_symbol(req, obj, &matchres, symnum)) {
4008 req->sym_out = matchres.sym_out;
4009 req->defobj_out = obj;
4013 if (matchres.vcount == 1) {
4014 req->sym_out = matchres.vsymp;
4015 req->defobj_out = obj;
4021 /* Search for symbol using GNU hash function */
4023 symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj)
4025 Elf_Addr bloom_word;
4026 const Elf32_Word *hashval;
4028 Sym_Match_Result matchres;
4029 unsigned int h1, h2;
4030 unsigned long symnum;
4032 matchres.sym_out = NULL;
4033 matchres.vsymp = NULL;
4034 matchres.vcount = 0;
4036 /* Pick right bitmask word from Bloom filter array */
4037 bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) &
4038 obj->maskwords_bm_gnu];
4040 /* Calculate modulus word size of gnu hash and its derivative */
4041 h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1);
4042 h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1));
4044 /* Filter out the "definitely not in set" queries */
4045 if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0)
4048 /* Locate hash chain and corresponding value element*/
4049 bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu];
4052 hashval = &obj->chain_zero_gnu[bucket];
4054 if (((*hashval ^ req->hash_gnu) >> 1) == 0) {
4055 symnum = hashval - obj->chain_zero_gnu;
4056 if (matched_symbol(req, obj, &matchres, symnum)) {
4057 req->sym_out = matchres.sym_out;
4058 req->defobj_out = obj;
4062 } while ((*hashval++ & 1) == 0);
4063 if (matchres.vcount == 1) {
4064 req->sym_out = matchres.vsymp;
4065 req->defobj_out = obj;
4072 trace_loaded_objects(Obj_Entry *obj)
4074 const char *fmt1, *fmt2, *fmt, *main_local, *list_containers;
4077 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
4080 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
4081 fmt1 = "\t%o => %p (%x)\n";
4083 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
4084 fmt2 = "\t%o (%x)\n";
4086 list_containers = _getenv_ld("LD_TRACE_LOADED_OBJECTS_ALL");
4088 for (; obj; obj = obj->next) {
4089 Needed_Entry *needed;
4093 if (list_containers && obj->needed != NULL)
4094 rtld_printf("%s:\n", obj->path);
4095 for (needed = obj->needed; needed; needed = needed->next) {
4096 if (needed->obj != NULL) {
4097 if (needed->obj->traced && !list_containers)
4099 needed->obj->traced = true;
4100 path = needed->obj->path;
4104 name = (char *)obj->strtab + needed->name;
4105 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
4107 fmt = is_lib ? fmt1 : fmt2;
4108 while ((c = *fmt++) != '\0') {
4134 rtld_putstr(main_local);
4137 rtld_putstr(obj_main->path);
4146 rtld_printf("%p", needed->obj ? needed->obj->mapbase :
4159 * Unload a dlopened object and its dependencies from memory and from
4160 * our data structures. It is assumed that the DAG rooted in the
4161 * object has already been unreferenced, and that the object has a
4162 * reference count of 0.
4165 unload_object(Obj_Entry *root)
4170 assert(root->refcount == 0);
4173 * Pass over the DAG removing unreferenced objects from
4174 * appropriate lists.
4176 unlink_object(root);
4178 /* Unmap all objects that are no longer referenced. */
4179 linkp = &obj_list->next;
4180 while ((obj = *linkp) != NULL) {
4181 if (obj->refcount == 0) {
4182 LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0,
4184 dbg("unloading \"%s\"", obj->path);
4185 unload_filtees(root);
4186 munmap(obj->mapbase, obj->mapsize);
4187 linkmap_delete(obj);
4198 unlink_object(Obj_Entry *root)
4202 if (root->refcount == 0) {
4203 /* Remove the object from the RTLD_GLOBAL list. */
4204 objlist_remove(&list_global, root);
4206 /* Remove the object from all objects' DAG lists. */
4207 STAILQ_FOREACH(elm, &root->dagmembers, link) {
4208 objlist_remove(&elm->obj->dldags, root);
4209 if (elm->obj != root)
4210 unlink_object(elm->obj);
4216 ref_dag(Obj_Entry *root)
4220 assert(root->dag_inited);
4221 STAILQ_FOREACH(elm, &root->dagmembers, link)
4222 elm->obj->refcount++;
4226 unref_dag(Obj_Entry *root)
4230 assert(root->dag_inited);
4231 STAILQ_FOREACH(elm, &root->dagmembers, link)
4232 elm->obj->refcount--;
4236 * Common code for MD __tls_get_addr().
4239 tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset)
4241 Elf_Addr* dtv = *dtvp;
4242 RtldLockState lockstate;
4244 /* Check dtv generation in case new modules have arrived */
4245 if (dtv[0] != tls_dtv_generation) {
4249 wlock_acquire(rtld_bind_lock, &lockstate);
4250 newdtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
4252 if (to_copy > tls_max_index)
4253 to_copy = tls_max_index;
4254 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
4255 newdtv[0] = tls_dtv_generation;
4256 newdtv[1] = tls_max_index;
4258 lock_release(rtld_bind_lock, &lockstate);
4259 dtv = *dtvp = newdtv;
4262 /* Dynamically allocate module TLS if necessary */
4263 if (!dtv[index + 1]) {
4264 /* Signal safe, wlock will block out signals. */
4265 wlock_acquire(rtld_bind_lock, &lockstate);
4266 if (!dtv[index + 1])
4267 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
4268 lock_release(rtld_bind_lock, &lockstate);
4270 return (void*) (dtv[index + 1] + offset);
4273 #if defined(RTLD_STATIC_TLS_VARIANT_II)
4276 * Allocate the static TLS area. Return a pointer to the TCB. The
4277 * static area is based on negative offsets relative to the tcb.
4279 * The TCB contains an errno pointer for the system call layer, but because
4280 * we are the RTLD we really have no idea how the caller was compiled so
4281 * the information has to be passed in. errno can either be:
4283 * type 0 errno is a simple non-TLS global pointer.
4284 * (special case for e.g. libc_rtld)
4285 * type 1 errno accessed by GOT entry (dynamically linked programs)
4286 * type 2 errno accessed by %gs:OFFSET (statically linked programs)
4289 allocate_tls(Obj_Entry *objs)
4294 struct tls_tcb *tcb;
4299 * Allocate the new TCB. static TLS storage is placed just before the
4300 * TCB to support the %gs:OFFSET (negative offset) model.
4302 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
4303 ~RTLD_STATIC_TLS_ALIGN_MASK;
4304 tcb = malloc(data_size + sizeof(*tcb));
4305 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */
4307 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr);
4308 dtv = malloc(dtv_size);
4309 bzero(dtv, dtv_size);
4311 #ifdef RTLD_TCB_HAS_SELF_POINTER
4312 tcb->tcb_self = tcb;
4315 tcb->tcb_pthread = NULL;
4317 dtv[0] = tls_dtv_generation;
4318 dtv[1] = tls_max_index;
4320 for (obj = objs; obj; obj = obj->next) {
4321 if (obj->tlsoffset) {
4322 addr = (Elf_Addr)tcb - obj->tlsoffset;
4323 memset((void *)(addr + obj->tlsinitsize),
4324 0, obj->tlssize - obj->tlsinitsize);
4326 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
4327 dtv[obj->tlsindex + 1] = addr;
4334 free_tls(struct tls_tcb *tcb)
4338 Elf_Addr tls_start, tls_end;
4341 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
4342 ~RTLD_STATIC_TLS_ALIGN_MASK;
4346 tls_end = (Elf_Addr)tcb;
4347 tls_start = (Elf_Addr)tcb - data_size;
4348 for (i = 0; i < dtv_size; i++) {
4349 if (dtv[i+2] != 0 && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) {
4350 free((void *)dtv[i+2]);
4354 free((void*) tls_start);
4358 #error "Unsupported TLS layout"
4362 * Allocate TLS block for module with given index.
4365 allocate_module_tls(int index)
4370 for (obj = obj_list; obj; obj = obj->next) {
4371 if (obj->tlsindex == index)
4375 _rtld_error("Can't find module with TLS index %d", index);
4379 p = malloc(obj->tlssize);
4381 _rtld_error("Cannot allocate TLS block for index %d", index);
4384 memcpy(p, obj->tlsinit, obj->tlsinitsize);
4385 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
4391 allocate_tls_offset(Obj_Entry *obj)
4398 if (obj->tlssize == 0) {
4399 obj->tls_done = true;
4403 if (obj->tlsindex == 1)
4404 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
4406 off = calculate_tls_offset(tls_last_offset, tls_last_size,
4407 obj->tlssize, obj->tlsalign);
4410 * If we have already fixed the size of the static TLS block, we
4411 * must stay within that size. When allocating the static TLS, we
4412 * leave a small amount of space spare to be used for dynamically
4413 * loading modules which use static TLS.
4415 if (tls_static_space) {
4416 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
4420 tls_last_offset = obj->tlsoffset = off;
4421 tls_last_size = obj->tlssize;
4422 obj->tls_done = true;
4428 free_tls_offset(Obj_Entry *obj)
4430 #ifdef RTLD_STATIC_TLS_VARIANT_II
4432 * If we were the last thing to allocate out of the static TLS
4433 * block, we give our space back to the 'allocator'. This is a
4434 * simplistic workaround to allow libGL.so.1 to be loaded and
4435 * unloaded multiple times. We only handle the Variant II
4436 * mechanism for now - this really needs a proper allocator.
4438 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
4439 == calculate_tls_end(tls_last_offset, tls_last_size)) {
4440 tls_last_offset -= obj->tlssize;
4447 _rtld_allocate_tls(void)
4449 struct tls_tcb *new_tcb;
4450 RtldLockState lockstate;
4452 wlock_acquire(rtld_bind_lock, &lockstate);
4453 new_tcb = allocate_tls(obj_list);
4454 lock_release(rtld_bind_lock, &lockstate);
4459 _rtld_free_tls(struct tls_tcb *tcb)
4461 RtldLockState lockstate;
4463 wlock_acquire(rtld_bind_lock, &lockstate);
4465 lock_release(rtld_bind_lock, &lockstate);
4469 object_add_name(Obj_Entry *obj, const char *name)
4475 entry = malloc(sizeof(Name_Entry) + len);
4477 if (entry != NULL) {
4478 strcpy(entry->name, name);
4479 STAILQ_INSERT_TAIL(&obj->names, entry, link);
4484 object_match_name(const Obj_Entry *obj, const char *name)
4488 STAILQ_FOREACH(entry, &obj->names, link) {
4489 if (strcmp(name, entry->name) == 0)
4496 locate_dependency(const Obj_Entry *obj, const char *name)
4498 const Objlist_Entry *entry;
4499 const Needed_Entry *needed;
4501 STAILQ_FOREACH(entry, &list_main, link) {
4502 if (object_match_name(entry->obj, name))
4506 for (needed = obj->needed; needed != NULL; needed = needed->next) {
4507 if (strcmp(obj->strtab + needed->name, name) == 0 ||
4508 (needed->obj != NULL && object_match_name(needed->obj, name))) {
4510 * If there is DT_NEEDED for the name we are looking for,
4511 * we are all set. Note that object might not be found if
4512 * dependency was not loaded yet, so the function can
4513 * return NULL here. This is expected and handled
4514 * properly by the caller.
4516 return (needed->obj);
4519 _rtld_error("%s: Unexpected inconsistency: dependency %s not found",
4525 check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj,
4526 const Elf_Vernaux *vna)
4528 const Elf_Verdef *vd;
4529 const char *vername;
4531 vername = refobj->strtab + vna->vna_name;
4532 vd = depobj->verdef;
4534 _rtld_error("%s: version %s required by %s not defined",
4535 depobj->path, vername, refobj->path);
4539 if (vd->vd_version != VER_DEF_CURRENT) {
4540 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4541 depobj->path, vd->vd_version);
4544 if (vna->vna_hash == vd->vd_hash) {
4545 const Elf_Verdaux *aux = (const Elf_Verdaux *)
4546 ((char *)vd + vd->vd_aux);
4547 if (strcmp(vername, depobj->strtab + aux->vda_name) == 0)
4550 if (vd->vd_next == 0)
4552 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4554 if (vna->vna_flags & VER_FLG_WEAK)
4556 _rtld_error("%s: version %s required by %s not found",
4557 depobj->path, vername, refobj->path);
4562 rtld_verify_object_versions(Obj_Entry *obj)
4564 const Elf_Verneed *vn;
4565 const Elf_Verdef *vd;
4566 const Elf_Verdaux *vda;
4567 const Elf_Vernaux *vna;
4568 const Obj_Entry *depobj;
4569 int maxvernum, vernum;
4571 if (obj->ver_checked)
4573 obj->ver_checked = true;
4577 * Walk over defined and required version records and figure out
4578 * max index used by any of them. Do very basic sanity checking
4582 while (vn != NULL) {
4583 if (vn->vn_version != VER_NEED_CURRENT) {
4584 _rtld_error("%s: Unsupported version %d of Elf_Verneed entry",
4585 obj->path, vn->vn_version);
4588 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4590 vernum = VER_NEED_IDX(vna->vna_other);
4591 if (vernum > maxvernum)
4593 if (vna->vna_next == 0)
4595 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4597 if (vn->vn_next == 0)
4599 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4603 while (vd != NULL) {
4604 if (vd->vd_version != VER_DEF_CURRENT) {
4605 _rtld_error("%s: Unsupported version %d of Elf_Verdef entry",
4606 obj->path, vd->vd_version);
4609 vernum = VER_DEF_IDX(vd->vd_ndx);
4610 if (vernum > maxvernum)
4612 if (vd->vd_next == 0)
4614 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4621 * Store version information in array indexable by version index.
4622 * Verify that object version requirements are satisfied along the
4625 obj->vernum = maxvernum + 1;
4626 obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry));
4629 while (vd != NULL) {
4630 if ((vd->vd_flags & VER_FLG_BASE) == 0) {
4631 vernum = VER_DEF_IDX(vd->vd_ndx);
4632 assert(vernum <= maxvernum);
4633 vda = (const Elf_Verdaux *)((char *)vd + vd->vd_aux);
4634 obj->vertab[vernum].hash = vd->vd_hash;
4635 obj->vertab[vernum].name = obj->strtab + vda->vda_name;
4636 obj->vertab[vernum].file = NULL;
4637 obj->vertab[vernum].flags = 0;
4639 if (vd->vd_next == 0)
4641 vd = (const Elf_Verdef *) ((char *)vd + vd->vd_next);
4645 while (vn != NULL) {
4646 depobj = locate_dependency(obj, obj->strtab + vn->vn_file);
4649 vna = (const Elf_Vernaux *) ((char *)vn + vn->vn_aux);
4651 if (check_object_provided_version(obj, depobj, vna))
4653 vernum = VER_NEED_IDX(vna->vna_other);
4654 assert(vernum <= maxvernum);
4655 obj->vertab[vernum].hash = vna->vna_hash;
4656 obj->vertab[vernum].name = obj->strtab + vna->vna_name;
4657 obj->vertab[vernum].file = obj->strtab + vn->vn_file;
4658 obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) ?
4659 VER_INFO_HIDDEN : 0;
4660 if (vna->vna_next == 0)
4662 vna = (const Elf_Vernaux *) ((char *)vna + vna->vna_next);
4664 if (vn->vn_next == 0)
4666 vn = (const Elf_Verneed *) ((char *)vn + vn->vn_next);
4672 rtld_verify_versions(const Objlist *objlist)
4674 Objlist_Entry *entry;
4678 STAILQ_FOREACH(entry, objlist, link) {
4680 * Skip dummy objects or objects that have their version requirements
4683 if (entry->obj->strtab == NULL || entry->obj->vertab != NULL)
4685 if (rtld_verify_object_versions(entry->obj) == -1) {
4687 if (ld_tracing == NULL)
4691 if (rc == 0 || ld_tracing != NULL)
4692 rc = rtld_verify_object_versions(&obj_rtld);
4697 fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
4702 vernum = VER_NDX(obj->versyms[symnum]);
4703 if (vernum >= obj->vernum) {
4704 _rtld_error("%s: symbol %s has wrong verneed value %d",
4705 obj->path, obj->strtab + symnum, vernum);
4706 } else if (obj->vertab[vernum].hash != 0) {
4707 return &obj->vertab[vernum];
4714 _rtld_get_stack_prot(void)
4717 return (stack_prot);
4721 map_stacks_exec(RtldLockState *lockstate)
4725 * Stack protection must be implemented in the kernel before the dynamic
4726 * linker can handle PT_GNU_STACK sections.
4727 * The following is the FreeBSD implementation of map_stacks_exec()
4728 * void (*thr_map_stacks_exec)(void);
4730 * if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0)
4732 * thr_map_stacks_exec = (void (*)(void))(uintptr_t)
4733 * get_program_var_addr("__pthread_map_stacks_exec", lockstate);
4734 * if (thr_map_stacks_exec != NULL) {
4735 * stack_prot |= PROT_EXEC;
4736 * thr_map_stacks_exec();
4742 symlook_init(SymLook *dst, const char *name)
4745 bzero(dst, sizeof(*dst));
4747 dst->hash = elf_hash(name);
4748 dst->hash_gnu = gnu_hash(name);
4752 symlook_init_from_req(SymLook *dst, const SymLook *src)
4755 dst->name = src->name;
4756 dst->hash = src->hash;
4757 dst->hash_gnu = src->hash_gnu;
4758 dst->ventry = src->ventry;
4759 dst->flags = src->flags;
4760 dst->defobj_out = NULL;
4761 dst->sym_out = NULL;
4762 dst->lockstate = src->lockstate;
4765 #ifdef ENABLE_OSRELDATE
4767 * Overrides for libc_pic-provided functions.
4771 __getosreldate(void)
4781 oid[1] = KERN_OSRELDATE;
4783 len = sizeof(osrel);
4784 error = sysctl(oid, 2, &osrel, &len, NULL, 0);
4785 if (error == 0 && osrel > 0 && len == sizeof(osrel))
4792 * No unresolved symbols for rtld.
4795 __pthread_cxa_finalize(struct dl_phdr_info *a)
4800 rtld_strerror(int errnum)
4803 if (errnum < 0 || errnum >= sys_nerr)
4804 return ("Unknown error");
4805 return (sys_errlist[errnum]);