Simplify code by using IF_DRAIN.
[dragonfly.git] / libexec / rtld-elf / rtld.c
CommitLineData
984263bc
MD
1/*-
2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * Copyright 2003 Alexander Kabaev <kan@FreeBSD.ORG>.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 * $FreeBSD: src/libexec/rtld-elf/rtld.c,v 1.43.2.15 2003/02/20 20:42:46 kan Exp $
15c48f1a 27 * $DragonFly: src/libexec/rtld-elf/rtld.c,v 1.22 2005/04/27 11:59:11 joerg Exp $
984263bc
MD
28 */
29
30/*
31 * Dynamic linker for ELF.
32 *
33 * John Polstra <jdp@polstra.com>.
34 */
35
36#ifndef __GNUC__
37#error "GCC is needed to compile this file"
38#endif
39
40#include <sys/param.h>
41#include <sys/mman.h>
42#include <sys/stat.h>
8ca15ec8 43#include <sys/resident.h>
bc633d63 44#include <sys/tls.h>
984263bc 45
9e2ee207
JS
46#include <machine/tls.h>
47
984263bc
MD
48#include <dlfcn.h>
49#include <err.h>
50#include <errno.h>
51#include <fcntl.h>
52#include <stdarg.h>
53#include <stdio.h>
54#include <stdlib.h>
55#include <string.h>
56#include <unistd.h>
57
58#include "debug.h"
59#include "rtld.h"
60
984263bc 61#define PATH_RTLD "/usr/libexec/ld-elf.so.1"
8ca15ec8 62#define LD_ARY_CACHE 16
984263bc
MD
63
64/* Types. */
65typedef void (*func_ptr_type)();
66typedef void * (*path_enum_proc) (const char *path, size_t len, void *arg);
67
68/*
69 * This structure provides a reentrant way to keep a list of objects and
70 * check which ones have already been processed in some way.
71 */
72typedef struct Struct_DoneList {
73 const Obj_Entry **objs; /* Array of object pointers */
74 unsigned int num_alloc; /* Allocated size of the array */
75 unsigned int num_used; /* Number of array slots used */
76} DoneList;
77
78/*
79 * Function declarations.
80 */
984263bc
MD
81static void die(void);
82static void digest_dynamic(Obj_Entry *);
8ca15ec8 83static const char *_getenv_ld(const char *id);
984263bc
MD
84static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
85static Obj_Entry *dlcheck(void *);
86static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *);
87static bool donelist_check(DoneList *, const Obj_Entry *);
88static void errmsg_restore(char *);
89static char *errmsg_save(void);
90static void *fill_search_info(const char *, size_t, void *);
91static char *find_library(const char *, const Obj_Entry *);
b6a22d96 92static Obj_Entry *find_object(const char *);
2d6b58a8 93static Obj_Entry *find_object2(const char *, int *, struct stat *);
984263bc
MD
94static const char *gethints(void);
95static void init_dag(Obj_Entry *);
96static void init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *);
97static void init_rtld(caddr_t);
98static void initlist_add_neededs(Needed_Entry *needed, Objlist *list);
99static void initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail,
100 Objlist *list);
101static bool is_exported(const Elf_Sym *);
102static void linkmap_add(Obj_Entry *);
103static void linkmap_delete(Obj_Entry *);
104static int load_needed_objects(Obj_Entry *);
105static int load_preload_objects(void);
106static Obj_Entry *load_object(char *);
107static void lock_check(void);
108static Obj_Entry *obj_from_addr(const void *);
109static void objlist_call_fini(Objlist *);
110static void objlist_call_init(Objlist *);
111static void objlist_clear(Objlist *);
112static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
113static void objlist_init(Objlist *);
114static void objlist_push_head(Objlist *, Obj_Entry *);
115static void objlist_push_tail(Objlist *, Obj_Entry *);
116static void objlist_remove(Objlist *, Obj_Entry *);
117static void objlist_remove_unref(Objlist *);
118static void *path_enumerate(const char *, path_enum_proc, void *);
119static int relocate_objects(Obj_Entry *, bool);
120static int rtld_dirname(const char *, char *);
121static void rtld_exit(void);
122static char *search_library_path(const char *, const char *);
123static const void **get_program_var_addr(const char *name);
124static void set_program_var(const char *, const void *);
125static const Elf_Sym *symlook_default(const char *, unsigned long hash,
126 const Obj_Entry *refobj, const Obj_Entry **defobj_out, bool in_plt);
127static const Elf_Sym *symlook_list(const char *, unsigned long,
128 Objlist *, const Obj_Entry **, bool in_plt, DoneList *);
129static void trace_loaded_objects(Obj_Entry *obj);
130static void unlink_object(Obj_Entry *);
131static void unload_object(Obj_Entry *);
132static void unref_dag(Obj_Entry *);
133
134void r_debug_state(struct r_debug*, struct link_map*);
135
136/*
137 * Data declarations.
138 */
139static char *error_message; /* Message for dlerror(), or NULL */
140struct r_debug r_debug; /* for GDB; */
141static bool trust; /* False for setuid and setgid programs */
8ca15ec8
MD
142static const char *ld_bind_now; /* Environment variable for immediate binding */
143static const char *ld_debug; /* Environment variable for debugging */
144static const char *ld_library_path; /* Environment variable for search path */
984263bc
MD
145static char *ld_preload; /* Environment variable for libraries to
146 load first */
8ca15ec8 147static const char *ld_tracing; /* Called from ldd(1) to print libs */
984263bc
MD
148static Obj_Entry *obj_list; /* Head of linked list of shared objects */
149static Obj_Entry **obj_tail; /* Link field of last object in list */
8ca15ec8 150static Obj_Entry **preload_tail;
984263bc
MD
151static Obj_Entry *obj_main; /* The main program shared object */
152static Obj_Entry obj_rtld; /* The dynamic linker shared object */
153static unsigned int obj_count; /* Number of objects in obj_list */
33a8b578 154static int ld_resident; /* Non-zero if resident */
8ca15ec8
MD
155static const char *ld_ary[LD_ARY_CACHE];
156static int ld_index;
984263bc
MD
157
158static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
159 STAILQ_HEAD_INITIALIZER(list_global);
160static Objlist list_main = /* Objects loaded at program startup */
161 STAILQ_HEAD_INITIALIZER(list_main);
162static Objlist list_fini = /* Objects needing fini() calls */
163 STAILQ_HEAD_INITIALIZER(list_fini);
164
165static LockInfo lockinfo;
166
167static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
168
169#define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
170
171extern Elf_Dyn _DYNAMIC;
172#pragma weak _DYNAMIC
173
174/*
175 * These are the functions the dynamic linker exports to application
176 * programs. They are the only symbols the dynamic linker is willing
177 * to export from itself.
178 */
179static func_ptr_type exports[] = {
180 (func_ptr_type) &_rtld_error,
181 (func_ptr_type) &dlclose,
182 (func_ptr_type) &dlerror,
183 (func_ptr_type) &dlopen,
184 (func_ptr_type) &dlsym,
185 (func_ptr_type) &dladdr,
984263bc 186 (func_ptr_type) &dlinfo,
55b88cae
DX
187#ifdef __i386__
188 (func_ptr_type) &___tls_get_addr,
189#endif
190 (func_ptr_type) &__tls_get_addr,
191 (func_ptr_type) &_rtld_allocate_tls,
192 (func_ptr_type) &_rtld_free_tls,
984263bc
MD
193 NULL
194};
195
196/*
197 * Global declarations normally provided by crt1. The dynamic linker is
198 * not built with crt1, so we have to provide them ourselves.
199 */
200char *__progname;
201char **environ;
202
55b88cae
DX
203/*
204 * Globals to control TLS allocation.
205 */
206size_t tls_last_offset; /* Static TLS offset of last module */
207size_t tls_last_size; /* Static TLS size of last module */
208size_t tls_static_space; /* Static TLS space allocated */
209int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
210int tls_max_index = 1; /* Largest module index allocated */
211
984263bc
MD
212/*
213 * Fill in a DoneList with an allocation large enough to hold all of
214 * the currently-loaded objects. Keep this as a macro since it calls
215 * alloca and we want that to occur within the scope of the caller.
216 */
217#define donelist_init(dlp) \
218 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
219 assert((dlp)->objs != NULL), \
220 (dlp)->num_alloc = obj_count, \
221 (dlp)->num_used = 0)
222
223static __inline void
224rlock_acquire(void)
225{
226 lockinfo.rlock_acquire(lockinfo.thelock);
227 atomic_incr_int(&lockinfo.rcount);
228 lock_check();
229}
230
231static __inline void
232wlock_acquire(void)
233{
234 lockinfo.wlock_acquire(lockinfo.thelock);
235 atomic_incr_int(&lockinfo.wcount);
236 lock_check();
237}
238
239static __inline void
240rlock_release(void)
241{
242 atomic_decr_int(&lockinfo.rcount);
243 lockinfo.rlock_release(lockinfo.thelock);
244}
245
246static __inline void
247wlock_release(void)
248{
249 atomic_decr_int(&lockinfo.wcount);
250 lockinfo.wlock_release(lockinfo.thelock);
251}
252
253/*
254 * Main entry point for dynamic linking. The first argument is the
255 * stack pointer. The stack is expected to be laid out as described
256 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
257 * Specifically, the stack pointer points to a word containing
258 * ARGC. Following that in the stack is a null-terminated sequence
259 * of pointers to argument strings. Then comes a null-terminated
260 * sequence of pointers to environment strings. Finally, there is a
261 * sequence of "auxiliary vector" entries.
262 *
263 * The second argument points to a place to store the dynamic linker's
264 * exit procedure pointer and the third to a place to store the main
265 * program's object.
266 *
267 * The return value is the main program's entry point.
268 */
269func_ptr_type
270_rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
271{
272 Elf_Auxinfo *aux_info[AT_COUNT];
273 int i;
274 int argc;
275 char **argv;
276 char **env;
277 Elf_Auxinfo *aux;
278 Elf_Auxinfo *auxp;
279 const char *argv0;
55b88cae 280 Objlist_Entry *entry;
984263bc 281 Obj_Entry *obj;
984263bc
MD
282 Objlist initlist;
283
8ca15ec8
MD
284 ld_index = 0; /* don't use old env cache in case we are resident */
285
984263bc
MD
286 /*
287 * On entry, the dynamic linker itself has not been relocated yet.
288 * Be very careful not to reference any global data until after
289 * init_rtld has returned. It is OK to reference file-scope statics
290 * and string constants, and to call static and global functions.
291 */
292
293 /* Find the auxiliary vector on the stack. */
294 argc = *sp++;
295 argv = (char **) sp;
296 sp += argc + 1; /* Skip over arguments and NULL terminator */
297 env = (char **) sp;
984263bc 298
33a8b578
MD
299 /*
300 * If we aren't already resident we have to dig out some more info.
301 * Note that auxinfo does not exist when we are resident.
302 */
303 if (ld_resident == 0) {
304 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
305 ;
306 aux = (Elf_Auxinfo *) sp;
307
308 /* Digest the auxiliary vector. */
309 for (i = 0; i < AT_COUNT; i++)
310 aux_info[i] = NULL;
311 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
312 if (auxp->a_type < AT_COUNT)
313 aux_info[auxp->a_type] = auxp;
314 }
315
316 /* Initialize and relocate ourselves. */
317 assert(aux_info[AT_BASE] != NULL);
318 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
319 }
984263bc
MD
320
321 __progname = obj_rtld.path;
322 argv0 = argv[0] != NULL ? argv[0] : "(null)";
323 environ = env;
324
8ca15ec8 325 trust = (geteuid() == getuid()) && (getegid() == getgid());
984263bc 326
8ca15ec8 327 ld_bind_now = _getenv_ld("LD_BIND_NOW");
984263bc 328 if (trust) {
8ca15ec8
MD
329 ld_debug = _getenv_ld("LD_DEBUG");
330 ld_library_path = _getenv_ld("LD_LIBRARY_PATH");
331 ld_preload = (char *)_getenv_ld("LD_PRELOAD");
984263bc 332 }
8ca15ec8 333 ld_tracing = _getenv_ld("LD_TRACE_LOADED_OBJECTS");
984263bc
MD
334
335 if (ld_debug != NULL && *ld_debug != '\0')
336 debug = 1;
337 dbg("%s is initialized, base address = %p", __progname,
338 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
339 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
340 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
341
33a8b578
MD
342 /*
343 * If we are resident we can skip work that we have already done.
344 * Note that the stack is reset and there is no Elf_Auxinfo
345 * when running from a resident image, and the static globals setup
346 * between here and resident_skip will have already been setup.
347 */
8ca15ec8 348 if (ld_resident)
33a8b578 349 goto resident_skip1;
33a8b578 350
984263bc
MD
351 /*
352 * Load the main program, or process its program header if it is
353 * already loaded.
354 */
355 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
356 int fd = aux_info[AT_EXECFD]->a_un.a_val;
357 dbg("loading main program");
358 obj_main = map_object(fd, argv0, NULL);
359 close(fd);
360 if (obj_main == NULL)
361 die();
362 } else { /* Main program already loaded. */
363 const Elf_Phdr *phdr;
364 int phnum;
365 caddr_t entry;
366
367 dbg("processing main program's program header");
368 assert(aux_info[AT_PHDR] != NULL);
369 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
370 assert(aux_info[AT_PHNUM] != NULL);
371 phnum = aux_info[AT_PHNUM]->a_un.a_val;
372 assert(aux_info[AT_PHENT] != NULL);
373 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
374 assert(aux_info[AT_ENTRY] != NULL);
375 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
376 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
377 die();
378 }
379
380 obj_main->path = xstrdup(argv0);
381 obj_main->mainprog = true;
382
383 /*
384 * Get the actual dynamic linker pathname from the executable if
385 * possible. (It should always be possible.) That ensures that
386 * gdb will find the right dynamic linker even if a non-standard
387 * one is being used.
388 */
389 if (obj_main->interp != NULL &&
390 strcmp(obj_main->interp, obj_rtld.path) != 0) {
391 free(obj_rtld.path);
392 obj_rtld.path = xstrdup(obj_main->interp);
b7b05c9f 393 __progname = obj_rtld.path;
984263bc
MD
394 }
395
396 digest_dynamic(obj_main);
397
398 linkmap_add(obj_main);
399 linkmap_add(&obj_rtld);
400
401 /* Link the main program into the list of objects. */
402 *obj_tail = obj_main;
403 obj_tail = &obj_main->next;
404 obj_count++;
405 obj_main->refcount++;
406 /* Make sure we don't call the main program's init and fini functions. */
407 obj_main->init = obj_main->fini = NULL;
408
409 /* Initialize a fake symbol for resolving undefined weak references. */
410 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
411 sym_zero.st_shndx = SHN_ABS;
412
413 dbg("loading LD_PRELOAD libraries");
414 if (load_preload_objects() == -1)
415 die();
416 preload_tail = obj_tail;
417
418 dbg("loading needed objects");
419 if (load_needed_objects(obj_main) == -1)
420 die();
421
422 /* Make a list of all objects loaded at startup. */
423 for (obj = obj_list; obj != NULL; obj = obj->next)
424 objlist_push_tail(&list_main, obj);
425
33a8b578
MD
426resident_skip1:
427
984263bc
MD
428 if (ld_tracing) { /* We're done */
429 trace_loaded_objects(obj_main);
430 exit(0);
431 }
432
33a8b578
MD
433 if (ld_resident) /* XXX clean this up! */
434 goto resident_skip2;
435
4a8d9350
JS
436 if (getenv("LD_DUMP_REL_PRE") != NULL) {
437 dump_relocations(obj_main);
438 exit (0);
439 }
440
55b88cae
DX
441 /* setup TLS for main thread */
442 dbg("initializing initial thread local storage");
443 STAILQ_FOREACH(entry, &list_main, link) {
444 /*
445 * Allocate all the initial objects out of the static TLS
446 * block even if they didn't ask for it.
447 */
448 allocate_tls_offset(entry->obj);
449 }
450 allocate_initial_tls(obj_list);
451
6192271e
MD
452 if (relocate_objects(obj_main,
453 ld_bind_now != NULL && *ld_bind_now != '\0') == -1)
454 die();
984263bc 455
6192271e
MD
456 dbg("doing copy relocations");
457 if (do_copy_relocations(obj_main) == -1)
458 die();
1c76efe5 459
33a8b578
MD
460resident_skip2:
461
8ca15ec8 462 if (_getenv_ld("LD_RESIDENT_UNREGISTER_NOW")) {
33a8b578
MD
463 if (exec_sys_unregister(-1) < 0) {
464 dbg("exec_sys_unregister failed %d\n", errno);
465 exit(errno);
466 }
467 dbg("exec_sys_unregister success\n");
468 exit(0);
469 }
984263bc 470
4a8d9350
JS
471 if (getenv("LD_DUMP_REL_POST") != NULL) {
472 dump_relocations(obj_main);
473 exit (0);
474 }
475
984263bc
MD
476 dbg("initializing key program variables");
477 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
478 set_program_var("environ", env);
479
8ca15ec8
MD
480 if (_getenv_ld("LD_RESIDENT_REGISTER_NOW")) {
481 extern void resident_start(void);
482 ld_resident = 1;
483 if (exec_sys_register(resident_start) < 0) {
484 dbg("exec_sys_register failed %d\n", errno);
485 exit(errno);
486 }
487 dbg("exec_sys_register success\n");
488 exit(0);
489 }
490
984263bc
MD
491 dbg("initializing thread locks");
492 lockdflt_init(&lockinfo);
493 lockinfo.thelock = lockinfo.lock_create(lockinfo.context);
494
495 /* Make a list of init functions to call. */
496 objlist_init(&initlist);
497 initlist_add_objects(obj_list, preload_tail, &initlist);
498
499 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
500
501 objlist_call_init(&initlist);
502 wlock_acquire();
503 objlist_clear(&initlist);
504 wlock_release();
505
8ca15ec8
MD
506
507
984263bc
MD
508 dbg("transferring control to program entry point = %p", obj_main->entry);
509
510 /* Return the exit procedure and the program entry point. */
511 *exit_proc = rtld_exit;
512 *objp = obj_main;
513 return (func_ptr_type) obj_main->entry;
514}
515
516Elf_Addr
517_rtld_bind(Obj_Entry *obj, Elf_Word reloff)
518{
519 const Elf_Rel *rel;
520 const Elf_Sym *def;
521 const Obj_Entry *defobj;
522 Elf_Addr *where;
523 Elf_Addr target;
524
525 rlock_acquire();
526 if (obj->pltrel)
527 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
528 else
529 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
530
531 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
532 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true, NULL);
533 if (def == NULL)
534 die();
535
536 target = (Elf_Addr)(defobj->relocbase + def->st_value);
537
538 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
539 defobj->strtab + def->st_name, basename(obj->path),
540 (void *)target, basename(defobj->path));
541
542 reloc_jmpslot(where, target);
543 rlock_release();
544 return target;
545}
546
547/*
548 * Error reporting function. Use it like printf. If formats the message
549 * into a buffer, and sets things up so that the next call to dlerror()
550 * will return the message.
551 */
552void
553_rtld_error(const char *fmt, ...)
554{
555 static char buf[512];
556 va_list ap;
557
558 va_start(ap, fmt);
559 vsnprintf(buf, sizeof buf, fmt, ap);
560 error_message = buf;
561 va_end(ap);
562}
563
564/*
565 * Return a dynamically-allocated copy of the current error message, if any.
566 */
567static char *
568errmsg_save(void)
569{
570 return error_message == NULL ? NULL : xstrdup(error_message);
571}
572
573/*
574 * Restore the current error message from a copy which was previously saved
575 * by errmsg_save(). The copy is freed.
576 */
577static void
578errmsg_restore(char *saved_msg)
579{
580 if (saved_msg == NULL)
581 error_message = NULL;
582 else {
583 _rtld_error("%s", saved_msg);
584 free(saved_msg);
585 }
586}
587
1c76efe5 588const char *
984263bc
MD
589basename(const char *name)
590{
591 const char *p = strrchr(name, '/');
592 return p != NULL ? p + 1 : name;
593}
594
595static void
596die(void)
597{
598 const char *msg = dlerror();
599
600 if (msg == NULL)
601 msg = "Fatal error";
602 errx(1, "%s", msg);
603}
604
605/*
606 * Process a shared object's DYNAMIC section, and save the important
607 * information in its Obj_Entry structure.
608 */
609static void
610digest_dynamic(Obj_Entry *obj)
611{
612 const Elf_Dyn *dynp;
613 Needed_Entry **needed_tail = &obj->needed;
614 const Elf_Dyn *dyn_rpath = NULL;
615 int plttype = DT_REL;
616
617 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
618 switch (dynp->d_tag) {
619
620 case DT_REL:
621 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
622 break;
623
624 case DT_RELSZ:
625 obj->relsize = dynp->d_un.d_val;
626 break;
627
628 case DT_RELENT:
629 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
630 break;
631
632 case DT_JMPREL:
633 obj->pltrel = (const Elf_Rel *)
634 (obj->relocbase + dynp->d_un.d_ptr);
635 break;
636
637 case DT_PLTRELSZ:
638 obj->pltrelsize = dynp->d_un.d_val;
639 break;
640
641 case DT_RELA:
642 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
643 break;
644
645 case DT_RELASZ:
646 obj->relasize = dynp->d_un.d_val;
647 break;
648
649 case DT_RELAENT:
650 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
651 break;
652
653 case DT_PLTREL:
654 plttype = dynp->d_un.d_val;
655 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
656 break;
657
658 case DT_SYMTAB:
659 obj->symtab = (const Elf_Sym *)
660 (obj->relocbase + dynp->d_un.d_ptr);
661 break;
662
663 case DT_SYMENT:
664 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
665 break;
666
667 case DT_STRTAB:
668 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
669 break;
670
671 case DT_STRSZ:
672 obj->strsize = dynp->d_un.d_val;
673 break;
674
675 case DT_HASH:
676 {
677 const Elf_Addr *hashtab = (const Elf_Addr *)
678 (obj->relocbase + dynp->d_un.d_ptr);
679 obj->nbuckets = hashtab[0];
680 obj->nchains = hashtab[1];
681 obj->buckets = hashtab + 2;
682 obj->chains = obj->buckets + obj->nbuckets;
683 }
684 break;
685
686 case DT_NEEDED:
687 if (!obj->rtld) {
688 Needed_Entry *nep = NEW(Needed_Entry);
689 nep->name = dynp->d_un.d_val;
690 nep->obj = NULL;
691 nep->next = NULL;
692
693 *needed_tail = nep;
694 needed_tail = &nep->next;
695 }
696 break;
697
698 case DT_PLTGOT:
699 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
700 break;
701
702 case DT_TEXTREL:
703 obj->textrel = true;
704 break;
705
706 case DT_SYMBOLIC:
707 obj->symbolic = true;
708 break;
709
710 case DT_RPATH:
167f7029 711 case DT_RUNPATH: /* XXX: process separately */
984263bc
MD
712 /*
713 * We have to wait until later to process this, because we
714 * might not have gotten the address of the string table yet.
715 */
716 dyn_rpath = dynp;
717 break;
718
719 case DT_SONAME:
720 /* Not used by the dynamic linker. */
721 break;
722
723 case DT_INIT:
724 obj->init = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr);
725 break;
726
727 case DT_FINI:
728 obj->fini = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr);
729 break;
730
731 case DT_DEBUG:
732 /* XXX - not implemented yet */
733 dbg("Filling in DT_DEBUG entry");
734 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
735 break;
736
167f7029
JS
737 case DT_FLAGS:
738 if (dynp->d_un.d_val & DF_ORIGIN) {
739 obj->origin_path = xmalloc(PATH_MAX);
740 if (rtld_dirname(obj->path, obj->origin_path) == -1)
741 die();
742 }
743 if (dynp->d_un.d_val & DF_SYMBOLIC)
744 obj->symbolic = true;
745 if (dynp->d_un.d_val & DF_TEXTREL)
746 obj->textrel = true;
747 if (dynp->d_un.d_val & DF_BIND_NOW)
748 obj->bind_now = true;
749 if (dynp->d_un.d_val & DF_STATIC_TLS)
750 ;
751 break;
752
984263bc
MD
753 default:
754 dbg("Ignoring d_tag %d = %#x", dynp->d_tag, dynp->d_tag);
755 break;
756 }
757 }
758
759 obj->traced = false;
760
761 if (plttype == DT_RELA) {
762 obj->pltrela = (const Elf_Rela *) obj->pltrel;
763 obj->pltrel = NULL;
764 obj->pltrelasize = obj->pltrelsize;
765 obj->pltrelsize = 0;
766 }
767
768 if (dyn_rpath != NULL)
769 obj->rpath = obj->strtab + dyn_rpath->d_un.d_val;
770}
771
772/*
773 * Process a shared object's program header. This is used only for the
774 * main program, when the kernel has already loaded the main program
775 * into memory before calling the dynamic linker. It creates and
776 * returns an Obj_Entry structure.
777 */
778static Obj_Entry *
779digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
780{
781 Obj_Entry *obj;
782 const Elf_Phdr *phlimit = phdr + phnum;
783 const Elf_Phdr *ph;
784 int nsegs = 0;
785
786 obj = obj_new();
787 for (ph = phdr; ph < phlimit; ph++) {
788 switch (ph->p_type) {
789
790 case PT_PHDR:
791 if ((const Elf_Phdr *)ph->p_vaddr != phdr) {
792 _rtld_error("%s: invalid PT_PHDR", path);
793 return NULL;
794 }
795 obj->phdr = (const Elf_Phdr *) ph->p_vaddr;
796 obj->phsize = ph->p_memsz;
797 break;
798
799 case PT_INTERP:
800 obj->interp = (const char *) ph->p_vaddr;
801 break;
802
803 case PT_LOAD:
804 if (nsegs == 0) { /* First load segment */
805 obj->vaddrbase = trunc_page(ph->p_vaddr);
806 obj->mapbase = (caddr_t) obj->vaddrbase;
807 obj->relocbase = obj->mapbase - obj->vaddrbase;
808 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
809 obj->vaddrbase;
810 } else { /* Last load segment */
811 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
812 obj->vaddrbase;
813 }
814 nsegs++;
815 break;
816
817 case PT_DYNAMIC:
818 obj->dynamic = (const Elf_Dyn *) ph->p_vaddr;
819 break;
55b88cae
DX
820
821 case PT_TLS:
822 obj->tlsindex = 1;
823 obj->tlssize = ph->p_memsz;
824 obj->tlsalign = ph->p_align;
825 obj->tlsinitsize = ph->p_filesz;
826 obj->tlsinit = (void*) ph->p_vaddr;
827 break;
984263bc
MD
828 }
829 }
830 if (nsegs < 1) {
831 _rtld_error("%s: too few PT_LOAD segments", path);
832 return NULL;
833 }
834
835 obj->entry = entry;
836 return obj;
837}
838
839static Obj_Entry *
840dlcheck(void *handle)
841{
842 Obj_Entry *obj;
843
844 for (obj = obj_list; obj != NULL; obj = obj->next)
845 if (obj == (Obj_Entry *) handle)
846 break;
847
848 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
849 _rtld_error("Invalid shared object handle %p", handle);
850 return NULL;
851 }
852 return obj;
853}
854
855/*
856 * If the given object is already in the donelist, return true. Otherwise
857 * add the object to the list and return false.
858 */
859static bool
860donelist_check(DoneList *dlp, const Obj_Entry *obj)
861{
862 unsigned int i;
863
864 for (i = 0; i < dlp->num_used; i++)
865 if (dlp->objs[i] == obj)
866 return true;
867 /*
868 * Our donelist allocation should always be sufficient. But if
869 * our threads locking isn't working properly, more shared objects
870 * could have been loaded since we allocated the list. That should
871 * never happen, but we'll handle it properly just in case it does.
872 */
873 if (dlp->num_used < dlp->num_alloc)
874 dlp->objs[dlp->num_used++] = obj;
875 return false;
876}
877
878/*
879 * Hash function for symbol table lookup. Don't even think about changing
880 * this. It is specified by the System V ABI.
881 */
882unsigned long
883elf_hash(const char *name)
884{
885 const unsigned char *p = (const unsigned char *) name;
886 unsigned long h = 0;
887 unsigned long g;
888
889 while (*p != '\0') {
890 h = (h << 4) + *p++;
891 if ((g = h & 0xf0000000) != 0)
892 h ^= g >> 24;
893 h &= ~g;
894 }
895 return h;
896}
897
898/*
899 * Find the library with the given name, and return its full pathname.
900 * The returned string is dynamically allocated. Generates an error
901 * message and returns NULL if the library cannot be found.
902 *
903 * If the second argument is non-NULL, then it refers to an already-
904 * loaded shared object, whose library search path will be searched.
905 *
906 * The search order is:
984263bc 907 * LD_LIBRARY_PATH
4e390e27 908 * rpath in the referencing file
984263bc
MD
909 * ldconfig hints
910 * /usr/lib
911 */
912static char *
913find_library(const char *name, const Obj_Entry *refobj)
914{
915 char *pathname;
916
917 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
918 if (name[0] != '/' && !trust) {
919 _rtld_error("Absolute pathname required for shared object \"%s\"",
920 name);
921 return NULL;
922 }
923 return xstrdup(name);
924 }
925
926 dbg(" Searching for \"%s\"", name);
927
928 if ((pathname = search_library_path(name, ld_library_path)) != NULL ||
929 (refobj != NULL &&
930 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
931 (pathname = search_library_path(name, gethints())) != NULL ||
932 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
933 return pathname;
934
446c0d3a
JS
935 if(refobj != NULL && refobj->path != NULL) {
936 _rtld_error("Shared object \"%s\" not found, required by \"%s\"",
937 name, basename(refobj->path));
938 } else {
939 _rtld_error("Shared object \"%s\" not found", name);
940 }
984263bc
MD
941 return NULL;
942}
943
944/*
945 * Given a symbol number in a referencing object, find the corresponding
946 * definition of the symbol. Returns a pointer to the symbol, or NULL if
947 * no definition was found. Returns a pointer to the Obj_Entry of the
948 * defining object via the reference parameter DEFOBJ_OUT.
949 */
950const Elf_Sym *
951find_symdef(unsigned long symnum, const Obj_Entry *refobj,
952 const Obj_Entry **defobj_out, bool in_plt, SymCache *cache)
953{
954 const Elf_Sym *ref;
955 const Elf_Sym *def;
956 const Obj_Entry *defobj;
957 const char *name;
958 unsigned long hash;
959
960 /*
961 * If we have already found this symbol, get the information from
962 * the cache.
963 */
964 if (symnum >= refobj->nchains)
965 return NULL; /* Bad object */
966 if (cache != NULL && cache[symnum].sym != NULL) {
967 *defobj_out = cache[symnum].obj;
968 return cache[symnum].sym;
969 }
970
971 ref = refobj->symtab + symnum;
972 name = refobj->strtab + ref->st_name;
973 hash = elf_hash(name);
974 defobj = NULL;
975
976 def = symlook_default(name, hash, refobj, &defobj, in_plt);
977
978 /*
979 * If we found no definition and the reference is weak, treat the
980 * symbol as having the value zero.
981 */
982 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
983 def = &sym_zero;
984 defobj = obj_main;
985 }
986
987 if (def != NULL) {
988 *defobj_out = defobj;
989 /* Record the information in the cache to avoid subsequent lookups. */
990 if (cache != NULL) {
991 cache[symnum].sym = def;
992 cache[symnum].obj = defobj;
993 }
994 } else
995 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
996 return def;
997}
998
999/*
1000 * Return the search path from the ldconfig hints file, reading it if
1001 * necessary. Returns NULL if there are problems with the hints file,
1002 * or if the search path there is empty.
1003 */
1004static const char *
1005gethints(void)
1006{
1007 static char *hints;
1008
1009 if (hints == NULL) {
1010 int fd;
1011 struct elfhints_hdr hdr;
1012 char *p;
1013
1014 /* Keep from trying again in case the hints file is bad. */
1015 hints = "";
1016
1017 if ((fd = open(_PATH_ELF_HINTS, O_RDONLY)) == -1)
1018 return NULL;
1019 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
1020 hdr.magic != ELFHINTS_MAGIC ||
1021 hdr.version != 1) {
1022 close(fd);
1023 return NULL;
1024 }
1025 p = xmalloc(hdr.dirlistlen + 1);
1026 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
1027 read(fd, p, hdr.dirlistlen + 1) != hdr.dirlistlen + 1) {
1028 free(p);
1029 close(fd);
1030 return NULL;
1031 }
1032 hints = p;
1033 close(fd);
1034 }
1035 return hints[0] != '\0' ? hints : NULL;
1036}
1037
1038static void
1039init_dag(Obj_Entry *root)
1040{
1041 DoneList donelist;
1042
1043 donelist_init(&donelist);
1044 init_dag1(root, root, &donelist);
1045}
1046
1047static void
1048init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp)
1049{
1050 const Needed_Entry *needed;
1051
1052 if (donelist_check(dlp, obj))
1053 return;
1054 objlist_push_tail(&obj->dldags, root);
1055 objlist_push_tail(&root->dagmembers, obj);
1056 for (needed = obj->needed; needed != NULL; needed = needed->next)
1057 if (needed->obj != NULL)
1058 init_dag1(root, needed->obj, dlp);
1059}
1060
1061/*
1062 * Initialize the dynamic linker. The argument is the address at which
1063 * the dynamic linker has been mapped into memory. The primary task of
1064 * this function is to relocate the dynamic linker.
1065 */
1066static void
1067init_rtld(caddr_t mapbase)
1068{
1069 /*
1070 * Conjure up an Obj_Entry structure for the dynamic linker.
1071 *
1072 * The "path" member is supposed to be dynamically-allocated, but we
1073 * aren't yet initialized sufficiently to do that. Below we will
1074 * replace the static version with a dynamically-allocated copy.
1075 */
1076 obj_rtld.path = PATH_RTLD;
1077 obj_rtld.rtld = true;
1078 obj_rtld.mapbase = mapbase;
1079#ifdef PIC
1080 obj_rtld.relocbase = mapbase;
1081#endif
1082 if (&_DYNAMIC != 0) {
1083 obj_rtld.dynamic = rtld_dynamic(&obj_rtld);
1084 digest_dynamic(&obj_rtld);
1085 assert(obj_rtld.needed == NULL);
1086 assert(!obj_rtld.textrel);
1087
1088 /*
1089 * Temporarily put the dynamic linker entry into the object list, so
1090 * that symbols can be found.
1091 */
1092 obj_list = &obj_rtld;
1093 obj_tail = &obj_rtld.next;
1094 obj_count = 1;
1095
1096 relocate_objects(&obj_rtld, true);
1097 }
1098
1099 /* Make the object list empty again. */
1100 obj_list = NULL;
1101 obj_tail = &obj_list;
1102 obj_count = 0;
1103
1104 /* Replace the path with a dynamically allocated copy. */
1105 obj_rtld.path = xstrdup(obj_rtld.path);
1106
1107 r_debug.r_brk = r_debug_state;
1108 r_debug.r_state = RT_CONSISTENT;
1109}
1110
1111/*
1112 * Add the init functions from a needed object list (and its recursive
1113 * needed objects) to "list". This is not used directly; it is a helper
1114 * function for initlist_add_objects(). The write lock must be held
1115 * when this function is called.
1116 */
1117static void
1118initlist_add_neededs(Needed_Entry *needed, Objlist *list)
1119{
1120 /* Recursively process the successor needed objects. */
1121 if (needed->next != NULL)
1122 initlist_add_neededs(needed->next, list);
1123
1124 /* Process the current needed object. */
1125 if (needed->obj != NULL)
1126 initlist_add_objects(needed->obj, &needed->obj->next, list);
1127}
1128
1129/*
1130 * Scan all of the DAGs rooted in the range of objects from "obj" to
1131 * "tail" and add their init functions to "list". This recurses over
1132 * the DAGs and ensure the proper init ordering such that each object's
1133 * needed libraries are initialized before the object itself. At the
1134 * same time, this function adds the objects to the global finalization
1135 * list "list_fini" in the opposite order. The write lock must be
1136 * held when this function is called.
1137 */
1138static void
1139initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
1140{
1141 if (obj->init_done)
1142 return;
1143 obj->init_done = true;
1144
1145 /* Recursively process the successor objects. */
1146 if (&obj->next != tail)
1147 initlist_add_objects(obj->next, tail, list);
1148
1149 /* Recursively process the needed objects. */
1150 if (obj->needed != NULL)
1151 initlist_add_neededs(obj->needed, list);
1152
1153 /* Add the object to the init list. */
1154 if (obj->init != NULL)
1155 objlist_push_tail(list, obj);
1156
1157 /* Add the object to the global fini list in the reverse order. */
1158 if (obj->fini != NULL)
1159 objlist_push_head(&list_fini, obj);
1160}
1161
1162static bool
1163is_exported(const Elf_Sym *def)
1164{
1165 func_ptr_type value;
1166 const func_ptr_type *p;
1167
1168 value = (func_ptr_type)(obj_rtld.relocbase + def->st_value);
1169 for (p = exports; *p != NULL; p++)
1170 if (*p == value)
1171 return true;
1172 return false;
1173}
1174
1175/*
1176 * Given a shared object, traverse its list of needed objects, and load
1177 * each of them. Returns 0 on success. Generates an error message and
1178 * returns -1 on failure.
1179 */
1180static int
1181load_needed_objects(Obj_Entry *first)
1182{
1183 Obj_Entry *obj;
1184
1185 for (obj = first; obj != NULL; obj = obj->next) {
1186 Needed_Entry *needed;
1187
1188 for (needed = obj->needed; needed != NULL; needed = needed->next) {
1189 const char *name = obj->strtab + needed->name;
1190 char *path = find_library(name, obj);
1191
1192 needed->obj = NULL;
1193 if (path == NULL && !ld_tracing)
1194 return -1;
1195
1196 if (path) {
1197 needed->obj = load_object(path);
1198 if (needed->obj == NULL && !ld_tracing)
1199 return -1; /* XXX - cleanup */
1200 }
1201 }
1202 }
1203
1204 return 0;
1205}
1206
1207static int
1208load_preload_objects(void)
1209{
1210 char *p = ld_preload;
1211 static const char delim[] = " \t:;";
1212
1213 if (p == NULL)
1214 return NULL;
1215
1216 p += strspn(p, delim);
1217 while (*p != '\0') {
1218 size_t len = strcspn(p, delim);
1219 char *path;
1220 char savech;
1221
1222 savech = p[len];
1223 p[len] = '\0';
1224 if ((path = find_library(p, NULL)) == NULL)
1225 return -1;
1226 if (load_object(path) == NULL)
1227 return -1; /* XXX - cleanup */
1228 p[len] = savech;
1229 p += len;
1230 p += strspn(p, delim);
1231 }
1232 return 0;
1233}
1234
b6a22d96 1235/*
2d6b58a8 1236 * Returns a pointer to the Obj_Entry for the object with the given path.
b6a22d96
JS
1237 * Returns NULL if no matching object was found.
1238 */
1239static Obj_Entry *
1240find_object(const char *path)
1241{
1242 Obj_Entry *obj;
1243
1244 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
1245 if (strcmp(obj->path, path) == 0)
1246 return(obj);
1247 }
1248 return(NULL);
1249}
1250
2d6b58a8
JS
1251/*
1252 * Returns a pointer to the Obj_Entry for the object matching device and
1253 * inode of the given path. If no matching object was found, the descriptor
1254 * is returned in fd.
1255 * Returns with obj == NULL && fd == -1 on error.
1256 */
1257static Obj_Entry *
1258find_object2(const char *path, int *fd, struct stat *sb)
1259{
1260 Obj_Entry *obj;
1261
1262 if ((*fd = open(path, O_RDONLY)) == -1) {
1263 _rtld_error("Cannot open \"%s\"", path);
1264 return(NULL);
1265 }
1266
1267 if (fstat(*fd, sb) == -1) {
1268 _rtld_error("Cannot fstat \"%s\"", path);
1269 close(*fd);
1270 *fd = -1;
1271 return NULL;
1272 }
1273
1274 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
1275 if (obj->ino == sb->st_ino && obj->dev == sb->st_dev) {
1276 close(*fd);
1277 break;
1278 }
1279 }
1280
1281 return(obj);
1282}
1283
984263bc
MD
1284/*
1285 * Load a shared object into memory, if it is not already loaded. The
1286 * argument must be a string allocated on the heap. This function assumes
1287 * responsibility for freeing it when necessary.
1288 *
1289 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1290 * on failure.
1291 */
1292static Obj_Entry *
1293load_object(char *path)
1294{
1295 Obj_Entry *obj;
1296 int fd = -1;
1297 struct stat sb;
1298
b6a22d96 1299 obj = find_object(path);
2d6b58a8 1300 if (obj != NULL) {
588c673f 1301 obj->refcount++;
2d6b58a8
JS
1302 free(path);
1303 return(obj);
1304 }
984263bc 1305
2d6b58a8 1306 obj = find_object2(path, &fd, &sb);
588c673f
JS
1307 if (obj != NULL) {
1308 obj->refcount++;
2d6b58a8
JS
1309 free(path);
1310 return(obj);
588c673f
JS
1311 } else if (fd == -1) {
1312 free(path);
1313 return(NULL);
984263bc
MD
1314 }
1315
2d6b58a8
JS
1316 dbg("loading \"%s\"", path);
1317 obj = map_object(fd, path, &sb);
1318 close(fd);
1319 if (obj == NULL) {
1320 free(path);
1321 return NULL;
1322 }
984263bc 1323
2d6b58a8
JS
1324 obj->path = path;
1325 digest_dynamic(obj);
984263bc 1326
2d6b58a8
JS
1327 *obj_tail = obj;
1328 obj_tail = &obj->next;
1329 obj_count++;
1330 linkmap_add(obj); /* for GDB & dlinfo() */
984263bc 1331
2d6b58a8
JS
1332 dbg(" %p .. %p: %s", obj->mapbase, obj->mapbase + obj->mapsize - 1,
1333 obj->path);
1334 if (obj->textrel)
1335 dbg(" WARNING: %s has impure text", obj->path);
984263bc
MD
1336
1337 obj->refcount++;
1338 return obj;
1339}
1340
1341/*
1342 * Check for locking violations and die if one is found.
1343 */
1344static void
1345lock_check(void)
1346{
1347 int rcount, wcount;
1348
1349 rcount = lockinfo.rcount;
1350 wcount = lockinfo.wcount;
1351 assert(rcount >= 0);
1352 assert(wcount >= 0);
1353 if (wcount > 1 || (wcount != 0 && rcount != 0)) {
1354 _rtld_error("Application locking error: %d readers and %d writers"
1355 " in dynamic linker. See DLLOCKINIT(3) in manual pages.",
1356 rcount, wcount);
1357 die();
1358 }
1359}
1360
1361static Obj_Entry *
1362obj_from_addr(const void *addr)
1363{
984263bc
MD
1364 Obj_Entry *obj;
1365
984263bc 1366 for (obj = obj_list; obj != NULL; obj = obj->next) {
984263bc
MD
1367 if (addr < (void *) obj->mapbase)
1368 continue;
c6873e56 1369 if (addr < (void *) (obj->mapbase + obj->mapsize))
984263bc
MD
1370 return obj;
1371 }
1372 return NULL;
1373}
1374
1375/*
1376 * Call the finalization functions for each of the objects in "list"
1377 * which are unreferenced. All of the objects are expected to have
1378 * non-NULL fini functions.
1379 */
1380static void
1381objlist_call_fini(Objlist *list)
1382{
1383 Objlist_Entry *elm;
1384 char *saved_msg;
1385
1386 /*
1387 * Preserve the current error message since a fini function might
1388 * call into the dynamic linker and overwrite it.
1389 */
1390 saved_msg = errmsg_save();
1391 STAILQ_FOREACH(elm, list, link) {
1392 if (elm->obj->refcount == 0) {
1393 dbg("calling fini function for %s", elm->obj->path);
1394 (*elm->obj->fini)();
1395 }
1396 }
1397 errmsg_restore(saved_msg);
1398}
1399
1400/*
1401 * Call the initialization functions for each of the objects in
1402 * "list". All of the objects are expected to have non-NULL init
1403 * functions.
1404 */
1405static void
1406objlist_call_init(Objlist *list)
1407{
1408 Objlist_Entry *elm;
1409 char *saved_msg;
1410
1411 /*
1412 * Preserve the current error message since an init function might
1413 * call into the dynamic linker and overwrite it.
1414 */
1415 saved_msg = errmsg_save();
1416 STAILQ_FOREACH(elm, list, link) {
1417 dbg("calling init function for %s", elm->obj->path);
1418 (*elm->obj->init)();
1419 }
1420 errmsg_restore(saved_msg);
1421}
1422
1423static void
1424objlist_clear(Objlist *list)
1425{
1426 Objlist_Entry *elm;
1427
1428 while (!STAILQ_EMPTY(list)) {
1429 elm = STAILQ_FIRST(list);
1430 STAILQ_REMOVE_HEAD(list, link);
1431 free(elm);
1432 }
1433}
1434
1435static Objlist_Entry *
1436objlist_find(Objlist *list, const Obj_Entry *obj)
1437{
1438 Objlist_Entry *elm;
1439
1440 STAILQ_FOREACH(elm, list, link)
1441 if (elm->obj == obj)
1442 return elm;
1443 return NULL;
1444}
1445
1446static void
1447objlist_init(Objlist *list)
1448{
1449 STAILQ_INIT(list);
1450}
1451
1452static void
1453objlist_push_head(Objlist *list, Obj_Entry *obj)
1454{
1455 Objlist_Entry *elm;
1456
1457 elm = NEW(Objlist_Entry);
1458 elm->obj = obj;
1459 STAILQ_INSERT_HEAD(list, elm, link);
1460}
1461
1462static void
1463objlist_push_tail(Objlist *list, Obj_Entry *obj)
1464{
1465 Objlist_Entry *elm;
1466
1467 elm = NEW(Objlist_Entry);
1468 elm->obj = obj;
1469 STAILQ_INSERT_TAIL(list, elm, link);
1470}
1471
1472static void
1473objlist_remove(Objlist *list, Obj_Entry *obj)
1474{
1475 Objlist_Entry *elm;
1476
1477 if ((elm = objlist_find(list, obj)) != NULL) {
1478 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1479 free(elm);
1480 }
1481}
1482
1483/*
1484 * Remove all of the unreferenced objects from "list".
1485 */
1486static void
1487objlist_remove_unref(Objlist *list)
1488{
1489 Objlist newlist;
1490 Objlist_Entry *elm;
1491
1492 STAILQ_INIT(&newlist);
1493 while (!STAILQ_EMPTY(list)) {
1494 elm = STAILQ_FIRST(list);
1495 STAILQ_REMOVE_HEAD(list, link);
1496 if (elm->obj->refcount == 0)
1497 free(elm);
1498 else
1499 STAILQ_INSERT_TAIL(&newlist, elm, link);
1500 }
1501 *list = newlist;
1502}
1503
1504/*
1505 * Relocate newly-loaded shared objects. The argument is a pointer to
1506 * the Obj_Entry for the first such object. All objects from the first
1507 * to the end of the list of objects are relocated. Returns 0 on success,
1508 * or -1 on failure.
1509 */
1510static int
1511relocate_objects(Obj_Entry *first, bool bind_now)
1512{
1513 Obj_Entry *obj;
1514
1515 for (obj = first; obj != NULL; obj = obj->next) {
1516 if (obj != &obj_rtld)
1517 dbg("relocating \"%s\"", obj->path);
1518 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
1519 obj->symtab == NULL || obj->strtab == NULL) {
1520 _rtld_error("%s: Shared object has no run-time symbol table",
1521 obj->path);
1522 return -1;
1523 }
1524
1525 if (obj->textrel) {
1526 /* There are relocations to the write-protected text segment. */
1527 if (mprotect(obj->mapbase, obj->textsize,
1528 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
1529 _rtld_error("%s: Cannot write-enable text segment: %s",
1530 obj->path, strerror(errno));
1531 return -1;
1532 }
1533 }
1534
1535 /* Process the non-PLT relocations. */
1536 if (reloc_non_plt(obj, &obj_rtld))
1537 return -1;
1538
4b89341e
MD
1539 /*
1540 * Reprotect the text segment. Make sure it is included in the
1541 * core dump since we modified it. This unfortunately causes the
1542 * entire text segment to core-out but we don't have much of a
1543 * choice. We could try to only reenable core dumps on pages
1544 * in which relocations occured but that is likely most of the text
1545 * pages anyway, and even that would not work because the rest of
1546 * the text pages would wind up as a read-only OBJT_DEFAULT object
1547 * (created due to our modifications) backed by the original OBJT_VNODE
1548 * object, and the ELF coredump code is currently only able to dump
1549 * vnode records for pure vnode-backed mappings, not vnode backings
1550 * to memory objects.
1551 */
1552 if (obj->textrel) {
1553 madvise(obj->mapbase, obj->textsize, MADV_CORE);
984263bc
MD
1554 if (mprotect(obj->mapbase, obj->textsize,
1555 PROT_READ|PROT_EXEC) == -1) {
1556 _rtld_error("%s: Cannot write-protect text segment: %s",
1557 obj->path, strerror(errno));
1558 return -1;
1559 }
1560 }
1561
1562 /* Process the PLT relocations. */
1563 if (reloc_plt(obj) == -1)
1564 return -1;
1565 /* Relocate the jump slots if we are doing immediate binding. */
167f7029 1566 if (obj->bind_now || bind_now)
984263bc
MD
1567 if (reloc_jmpslots(obj) == -1)
1568 return -1;
1569
1570
1571 /*
1572 * Set up the magic number and version in the Obj_Entry. These
1573 * were checked in the crt1.o from the original ElfKit, so we
1574 * set them for backward compatibility.
1575 */
1576 obj->magic = RTLD_MAGIC;
1577 obj->version = RTLD_VERSION;
1578
1579 /* Set the special PLT or GOT entries. */
1580 init_pltgot(obj);
1581 }
1582
1583 return 0;
1584}
1585
1586/*
1587 * Cleanup procedure. It will be called (by the atexit mechanism) just
1588 * before the process exits.
1589 */
1590static void
1591rtld_exit(void)
1592{
1593 Obj_Entry *obj;
1594
1595 dbg("rtld_exit()");
1596 /* Clear all the reference counts so the fini functions will be called. */
1597 for (obj = obj_list; obj != NULL; obj = obj->next)
1598 obj->refcount = 0;
1599 objlist_call_fini(&list_fini);
1600 /* No need to remove the items from the list, since we are exiting. */
1601}
1602
1603static void *
1604path_enumerate(const char *path, path_enum_proc callback, void *arg)
1605{
1606 if (path == NULL)
1607 return (NULL);
1608
1609 path += strspn(path, ":;");
1610 while (*path != '\0') {
1611 size_t len;
1612 char *res;
1613
1614 len = strcspn(path, ":;");
1615 res = callback(path, len, arg);
1616
1617 if (res != NULL)
1618 return (res);
1619
1620 path += len;
1621 path += strspn(path, ":;");
1622 }
1623
1624 return (NULL);
1625}
1626
1627struct try_library_args {
1628 const char *name;
1629 size_t namelen;
1630 char *buffer;
1631 size_t buflen;
1632};
1633
1634static void *
1635try_library_path(const char *dir, size_t dirlen, void *param)
1636{
1637 struct try_library_args *arg;
1638
1639 arg = param;
1640 if (*dir == '/' || trust) {
1641 char *pathname;
1642
1643 if (dirlen + 1 + arg->namelen + 1 > arg->buflen)
1644 return (NULL);
1645
1646 pathname = arg->buffer;
1647 strncpy(pathname, dir, dirlen);
1648 pathname[dirlen] = '/';
1649 strcpy(pathname + dirlen + 1, arg->name);
1650
1651 dbg(" Trying \"%s\"", pathname);
1652 if (access(pathname, F_OK) == 0) { /* We found it */
1653 pathname = xmalloc(dirlen + 1 + arg->namelen + 1);
1654 strcpy(pathname, arg->buffer);
1655 return (pathname);
1656 }
1657 }
1658 return (NULL);
1659}
1660
1661static char *
1662search_library_path(const char *name, const char *path)
1663{
1664 char *p;
1665 struct try_library_args arg;
1666
1667 if (path == NULL)
1668 return NULL;
1669
1670 arg.name = name;
1671 arg.namelen = strlen(name);
1672 arg.buffer = xmalloc(PATH_MAX);
1673 arg.buflen = PATH_MAX;
1674
1675 p = path_enumerate(path, try_library_path, &arg);
1676
1677 free(arg.buffer);
1678
1679 return (p);
1680}
1681
1682int
1683dlclose(void *handle)
1684{
1685 Obj_Entry *root;
1686
1687 wlock_acquire();
1688 root = dlcheck(handle);
1689 if (root == NULL) {
1690 wlock_release();
1691 return -1;
1692 }
1693
1694 /* Unreference the object and its dependencies. */
1695 root->dl_refcount--;
1696 unref_dag(root);
1697
1698 if (root->refcount == 0) {
1699 /*
1700 * The object is no longer referenced, so we must unload it.
1701 * First, call the fini functions with no locks held.
1702 */
1703 wlock_release();
1704 objlist_call_fini(&list_fini);
1705 wlock_acquire();
1706 objlist_remove_unref(&list_fini);
1707
1708 /* Finish cleaning up the newly-unreferenced objects. */
1709 GDB_STATE(RT_DELETE,&root->linkmap);
1710 unload_object(root);
1711 GDB_STATE(RT_CONSISTENT,NULL);
1712 }
1713 wlock_release();
1714 return 0;
1715}
1716
1717const char *
1718dlerror(void)
1719{
1720 char *msg = error_message;
1721 error_message = NULL;
1722 return msg;
1723}
1724
984263bc
MD
1725void *
1726dlopen(const char *name, int mode)
1727{
1728 Obj_Entry **old_obj_tail;
1729 Obj_Entry *obj;
1730 Objlist initlist;
1731 int result;
1732
1733 ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1";
1734 if (ld_tracing != NULL)
1735 environ = (char **)*get_program_var_addr("environ");
1736
1737 objlist_init(&initlist);
1738
1739 wlock_acquire();
1740 GDB_STATE(RT_ADD,NULL);
1741
1742 old_obj_tail = obj_tail;
1743 obj = NULL;
1744 if (name == NULL) {
1745 obj = obj_main;
1746 obj->refcount++;
1747 } else {
1748 char *path = find_library(name, obj_main);
1749 if (path != NULL)
1750 obj = load_object(path);
1751 }
1752
1753 if (obj) {
1754 obj->dl_refcount++;
8ca15ec8 1755 if ((mode & RTLD_GLOBAL) && objlist_find(&list_global, obj) == NULL)
984263bc
MD
1756 objlist_push_tail(&list_global, obj);
1757 mode &= RTLD_MODEMASK;
1758 if (*old_obj_tail != NULL) { /* We loaded something new. */
1759 assert(*old_obj_tail == obj);
1760
1761 result = load_needed_objects(obj);
1762 if (result != -1 && ld_tracing)
1763 goto trace;
1764
1765 if (result == -1 ||
1766 (init_dag(obj), relocate_objects(obj, mode == RTLD_NOW)) == -1) {
1767 obj->dl_refcount--;
1768 unref_dag(obj);
1769 if (obj->refcount == 0)
1770 unload_object(obj);
1771 obj = NULL;
1772 } else {
1773 /* Make list of init functions to call. */
1774 initlist_add_objects(obj, &obj->next, &initlist);
1775 }
1776 } else if (ld_tracing)
1777 goto trace;
1778 }
1779
1780 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
1781
1782 /* Call the init functions with no locks held. */
1783 wlock_release();
1784 objlist_call_init(&initlist);
1785 wlock_acquire();
1786 objlist_clear(&initlist);
1787 wlock_release();
1788 return obj;
1789trace:
1790 trace_loaded_objects(obj);
1791 wlock_release();
1792 exit(0);
1793}
1794
1795void *
1796dlsym(void *handle, const char *name)
1797{
1798 const Obj_Entry *obj;
1799 unsigned long hash;
1800 const Elf_Sym *def;
1801 const Obj_Entry *defobj;
1802
1803 hash = elf_hash(name);
1804 def = NULL;
1805 defobj = NULL;
1806
1807 rlock_acquire();
1808 if (handle == NULL || handle == RTLD_NEXT ||
1809 handle == RTLD_DEFAULT || handle == RTLD_SELF) {
1810 void *retaddr;
1811
1812 retaddr = __builtin_return_address(0); /* __GNUC__ only */
1813 if ((obj = obj_from_addr(retaddr)) == NULL) {
1814 _rtld_error("Cannot determine caller's shared object");
1815 rlock_release();
1816 return NULL;
1817 }
1818 if (handle == NULL) { /* Just the caller's shared object. */
1819 def = symlook_obj(name, hash, obj, true);
1820 defobj = obj;
1821 } else if (handle == RTLD_NEXT || /* Objects after caller's */
1822 handle == RTLD_SELF) { /* ... caller included */
1823 if (handle == RTLD_NEXT)
1824 obj = obj->next;
1825 for (; obj != NULL; obj = obj->next) {
1826 if ((def = symlook_obj(name, hash, obj, true)) != NULL) {
1827 defobj = obj;
1828 break;
1829 }
1830 }
1831 } else {
1832 assert(handle == RTLD_DEFAULT);
1833 def = symlook_default(name, hash, obj, &defobj, true);
1834 }
1835 } else {
1836 if ((obj = dlcheck(handle)) == NULL) {
1837 rlock_release();
1838 return NULL;
1839 }
1840
1841 if (obj->mainprog) {
1842 DoneList donelist;
1843
1844 /* Search main program and all libraries loaded by it. */
1845 donelist_init(&donelist);
1846 def = symlook_list(name, hash, &list_main, &defobj, true,
1847 &donelist);
1848 } else {
1849 /*
1850 * XXX - This isn't correct. The search should include the whole
1851 * DAG rooted at the given object.
1852 */
1853 def = symlook_obj(name, hash, obj, true);
1854 defobj = obj;
1855 }
1856 }
1857
1858 if (def != NULL) {
1859 rlock_release();
1860 return defobj->relocbase + def->st_value;
1861 }
1862
1863 _rtld_error("Undefined symbol \"%s\"", name);
1864 rlock_release();
1865 return NULL;
1866}
1867
1868int
1869dladdr(const void *addr, Dl_info *info)
1870{
1871 const Obj_Entry *obj;
1872 const Elf_Sym *def;
1873 void *symbol_addr;
1874 unsigned long symoffset;
1875
1876 rlock_acquire();
1877 obj = obj_from_addr(addr);
1878 if (obj == NULL) {
1879 _rtld_error("No shared object contains address");
1880 rlock_release();
1881 return 0;
1882 }
1883 info->dli_fname = obj->path;
1884 info->dli_fbase = obj->mapbase;
1885 info->dli_saddr = (void *)0;
1886 info->dli_sname = NULL;
1887
1888 /*
1889 * Walk the symbol list looking for the symbol whose address is
1890 * closest to the address sent in.
1891 */
1892 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
1893 def = obj->symtab + symoffset;
1894
1895 /*
1896 * For skip the symbol if st_shndx is either SHN_UNDEF or
1897 * SHN_COMMON.
1898 */
1899 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
1900 continue;
1901
1902 /*
1903 * If the symbol is greater than the specified address, or if it
1904 * is further away from addr than the current nearest symbol,
1905 * then reject it.
1906 */
1907 symbol_addr = obj->relocbase + def->st_value;
1908 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
1909 continue;
1910
1911 /* Update our idea of the nearest symbol. */
1912 info->dli_sname = obj->strtab + def->st_name;
1913 info->dli_saddr = symbol_addr;
1914
1915 /* Exact match? */
1916 if (info->dli_saddr == addr)
1917 break;
1918 }
1919 rlock_release();
1920 return 1;
1921}
1922
1923int
1924dlinfo(void *handle, int request, void *p)
1925{
1926 const Obj_Entry *obj;
1927 int error;
1928
1929 rlock_acquire();
1930
1931 if (handle == NULL || handle == RTLD_SELF) {
1932 void *retaddr;
1933
1934 retaddr = __builtin_return_address(0); /* __GNUC__ only */
1935 if ((obj = obj_from_addr(retaddr)) == NULL)
1936 _rtld_error("Cannot determine caller's shared object");
1937 } else
1938 obj = dlcheck(handle);
1939
1940 if (obj == NULL) {
1941 rlock_release();
1942 return (-1);
1943 }
1944
1945 error = 0;
1946 switch (request) {
1947 case RTLD_DI_LINKMAP:
1948 *((struct link_map const **)p) = &obj->linkmap;
1949 break;
1950 case RTLD_DI_ORIGIN:
1951 error = rtld_dirname(obj->path, p);
1952 break;
1953
1954 case RTLD_DI_SERINFOSIZE:
1955 case RTLD_DI_SERINFO:
1956 error = do_search_info(obj, request, (struct dl_serinfo *)p);
1957 break;
1958
1959 default:
1960 _rtld_error("Invalid request %d passed to dlinfo()", request);
1961 error = -1;
1962 }
1963
1964 rlock_release();
1965
1966 return (error);
1967}
1968
1969struct fill_search_info_args {
1970 int request;
1971 unsigned int flags;
1972 Dl_serinfo *serinfo;
1973 Dl_serpath *serpath;
1974 char *strspace;
1975};
1976
1977static void *
1978fill_search_info(const char *dir, size_t dirlen, void *param)
1979{
1980 struct fill_search_info_args *arg;
1981
1982 arg = param;
1983
1984 if (arg->request == RTLD_DI_SERINFOSIZE) {
1985 arg->serinfo->dls_cnt ++;
1986 arg->serinfo->dls_size += dirlen + 1;
1987 } else {
1988 struct dl_serpath *s_entry;
1989
1990 s_entry = arg->serpath;
1991 s_entry->dls_name = arg->strspace;
1992 s_entry->dls_flags = arg->flags;
1993
1994 strncpy(arg->strspace, dir, dirlen);
1995 arg->strspace[dirlen] = '\0';
1996
1997 arg->strspace += dirlen + 1;
1998 arg->serpath++;
1999 }
2000
2001 return (NULL);
2002}
2003
2004static int
2005do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info)
2006{
2007 struct dl_serinfo _info;
2008 struct fill_search_info_args args;
2009
2010 args.request = RTLD_DI_SERINFOSIZE;
2011 args.serinfo = &_info;
2012
2013 _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath);
2014 _info.dls_cnt = 0;
2015
2016 path_enumerate(ld_library_path, fill_search_info, &args);
2017 path_enumerate(obj->rpath, fill_search_info, &args);
2018 path_enumerate(gethints(), fill_search_info, &args);
2019 path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args);
2020
2021
2022 if (request == RTLD_DI_SERINFOSIZE) {
2023 info->dls_size = _info.dls_size;
2024 info->dls_cnt = _info.dls_cnt;
2025 return (0);
2026 }
2027
2028 if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) {
2029 _rtld_error("Uninitialized Dl_serinfo struct passed to dlinfo()");
2030 return (-1);
2031 }
2032
2033 args.request = RTLD_DI_SERINFO;
2034 args.serinfo = info;
2035 args.serpath = &info->dls_serpath[0];
2036 args.strspace = (char *)&info->dls_serpath[_info.dls_cnt];
2037
2038 args.flags = LA_SER_LIBPATH;
2039 if (path_enumerate(ld_library_path, fill_search_info, &args) != NULL)
2040 return (-1);
2041
2042 args.flags = LA_SER_RUNPATH;
2043 if (path_enumerate(obj->rpath, fill_search_info, &args) != NULL)
2044 return (-1);
2045
2046 args.flags = LA_SER_CONFIG;
2047 if (path_enumerate(gethints(), fill_search_info, &args) != NULL)
2048 return (-1);
2049
2050 args.flags = LA_SER_DEFAULT;
2051 if (path_enumerate(STANDARD_LIBRARY_PATH, fill_search_info, &args) != NULL)
2052 return (-1);
2053 return (0);
2054}
2055
2056static int
2057rtld_dirname(const char *path, char *bname)
2058{
2059 const char *endp;
2060
2061 /* Empty or NULL string gets treated as "." */
2062 if (path == NULL || *path == '\0') {
2063 bname[0] = '.';
2064 bname[1] = '\0';
2065 return (0);
2066 }
2067
2068 /* Strip trailing slashes */
2069 endp = path + strlen(path) - 1;
2070 while (endp > path && *endp == '/')
2071 endp--;
2072
2073 /* Find the start of the dir */
2074 while (endp > path && *endp != '/')
2075 endp--;
2076
2077 /* Either the dir is "/" or there are no slashes */
2078 if (endp == path) {
2079 bname[0] = *endp == '/' ? '/' : '.';
2080 bname[1] = '\0';
2081 return (0);
2082 } else {
2083 do {
2084 endp--;
2085 } while (endp > path && *endp == '/');
2086 }
2087
2088 if (endp - path + 2 > PATH_MAX)
2089 {
2090 _rtld_error("Filename is too long: %s", path);
2091 return(-1);
2092 }
2093
2094 strncpy(bname, path, endp - path + 1);
2095 bname[endp - path + 1] = '\0';
2096 return (0);
2097}
2098
2099static void
2100linkmap_add(Obj_Entry *obj)
2101{
2102 struct link_map *l = &obj->linkmap;
2103 struct link_map *prev;
2104
2105 obj->linkmap.l_name = obj->path;
2106 obj->linkmap.l_addr = obj->mapbase;
2107 obj->linkmap.l_ld = obj->dynamic;
2108#ifdef __mips__
2109 /* GDB needs load offset on MIPS to use the symbols */
2110 obj->linkmap.l_offs = obj->relocbase;
2111#endif
2112
2113 if (r_debug.r_map == NULL) {
2114 r_debug.r_map = l;
2115 return;
2116 }
2117
2118 /*
2119 * Scan to the end of the list, but not past the entry for the
2120 * dynamic linker, which we want to keep at the very end.
2121 */
2122 for (prev = r_debug.r_map;
2123 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
2124 prev = prev->l_next)
2125 ;
2126
2127 /* Link in the new entry. */
2128 l->l_prev = prev;
2129 l->l_next = prev->l_next;
2130 if (l->l_next != NULL)
2131 l->l_next->l_prev = l;
2132 prev->l_next = l;
2133}
2134
2135static void
2136linkmap_delete(Obj_Entry *obj)
2137{
2138 struct link_map *l = &obj->linkmap;
2139
2140 if (l->l_prev == NULL) {
2141 if ((r_debug.r_map = l->l_next) != NULL)
2142 l->l_next->l_prev = NULL;
2143 return;
2144 }
2145
2146 if ((l->l_prev->l_next = l->l_next) != NULL)
2147 l->l_next->l_prev = l->l_prev;
2148}
2149
2150/*
2151 * Function for the debugger to set a breakpoint on to gain control.
2152 *
2153 * The two parameters allow the debugger to easily find and determine
2154 * what the runtime loader is doing and to whom it is doing it.
2155 *
2156 * When the loadhook trap is hit (r_debug_state, set at program
2157 * initialization), the arguments can be found on the stack:
2158 *
2159 * +8 struct link_map *m
2160 * +4 struct r_debug *rd
2161 * +0 RetAddr
2162 */
2163void
2164r_debug_state(struct r_debug* rd, struct link_map *m)
2165{
2166}
2167
2168/*
2169 * Get address of the pointer variable in the main program.
2170 */
2171static const void **
2172get_program_var_addr(const char *name)
2173{
2174 const Obj_Entry *obj;
2175 unsigned long hash;
2176
2177 hash = elf_hash(name);
2178 for (obj = obj_main; obj != NULL; obj = obj->next) {
2179 const Elf_Sym *def;
2180
2181 if ((def = symlook_obj(name, hash, obj, false)) != NULL) {
2182 const void **addr;
2183
2184 addr = (const void **)(obj->relocbase + def->st_value);
2185 return addr;
2186 }
2187 }
2188 return NULL;
2189}
2190
2191/*
2192 * Set a pointer variable in the main program to the given value. This
2193 * is used to set key variables such as "environ" before any of the
2194 * init functions are called.
2195 */
2196static void
2197set_program_var(const char *name, const void *value)
2198{
2199 const void **addr;
2200
2201 if ((addr = get_program_var_addr(name)) != NULL) {
2202 dbg("\"%s\": *%p <-- %p", name, addr, value);
2203 *addr = value;
2204 }
2205}
2206
8ca15ec8
MD
2207/*
2208 * This is a special version of getenv which is far more efficient
2209 * at finding LD_ environment vars.
2210 */
2211static
2212const char *
2213_getenv_ld(const char *id)
2214{
2215 const char *envp;
2216 int i, j;
2217 int idlen = strlen(id);
2218
2219 if (ld_index == LD_ARY_CACHE)
2220 return(getenv(id));
2221 if (ld_index == 0) {
2222 for (i = j = 0; (envp = environ[i]) != NULL && j < LD_ARY_CACHE; ++i) {
2223 if (envp[0] == 'L' && envp[1] == 'D' && envp[2] == '_')
2224 ld_ary[j++] = envp;
2225 }
2226 if (j == 0)
2227 ld_ary[j++] = "";
2228 ld_index = j;
2229 }
2230 for (i = ld_index - 1; i >= 0; --i) {
2231 if (strncmp(ld_ary[i], id, idlen) == 0 && ld_ary[i][idlen] == '=')
2232 return(ld_ary[i] + idlen + 1);
2233 }
2234 return(NULL);
2235}
2236
984263bc
MD
2237/*
2238 * Given a symbol name in a referencing object, find the corresponding
2239 * definition of the symbol. Returns a pointer to the symbol, or NULL if
2240 * no definition was found. Returns a pointer to the Obj_Entry of the
2241 * defining object via the reference parameter DEFOBJ_OUT.
2242 */
2243static const Elf_Sym *
2244symlook_default(const char *name, unsigned long hash,
2245 const Obj_Entry *refobj, const Obj_Entry **defobj_out, bool in_plt)
2246{
2247 DoneList donelist;
2248 const Elf_Sym *def;
2249 const Elf_Sym *symp;
2250 const Obj_Entry *obj;
2251 const Obj_Entry *defobj;
2252 const Objlist_Entry *elm;
2253 def = NULL;
2254 defobj = NULL;
2255 donelist_init(&donelist);
2256
2257 /* Look first in the referencing object if linked symbolically. */
2258 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
2259 symp = symlook_obj(name, hash, refobj, in_plt);
2260 if (symp != NULL) {
2261 def = symp;
2262 defobj = refobj;
2263 }
2264 }
2265
2266 /* Search all objects loaded at program start up. */
2267 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2268 symp = symlook_list(name, hash, &list_main, &obj, in_plt, &donelist);
2269 if (symp != NULL &&
2270 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2271 def = symp;
2272 defobj = obj;
2273 }
2274 }
2275
2276 /* Search all DAGs whose roots are RTLD_GLOBAL objects. */
2277 STAILQ_FOREACH(elm, &list_global, link) {
2278 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
2279 break;
2280 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, in_plt,
2281 &donelist);
2282 if (symp != NULL &&
2283 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2284 def = symp;
2285 defobj = obj;
2286 }
2287 }
2288
2289 /* Search all dlopened DAGs containing the referencing object. */
2290 STAILQ_FOREACH(elm, &refobj->dldags, link) {
2291 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
2292 break;
2293 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, in_plt,
2294 &donelist);
2295 if (symp != NULL &&
2296 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
2297 def = symp;
2298 defobj = obj;
2299 }
2300 }
2301
2302 /*
2303 * Search the dynamic linker itself, and possibly resolve the
2304 * symbol from there. This is how the application links to
2305 * dynamic linker services such as dlopen. Only the values listed
2306 * in the "exports" array can be resolved from the dynamic linker.
2307 */
2308 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
2309 symp = symlook_obj(name, hash, &obj_rtld, in_plt);
2310 if (symp != NULL && is_exported(symp)) {
2311 def = symp;
2312 defobj = &obj_rtld;
2313 }
2314 }
2315
2316 if (def != NULL)
2317 *defobj_out = defobj;
2318 return def;
2319}
2320
2321static const Elf_Sym *
2322symlook_list(const char *name, unsigned long hash, Objlist *objlist,
2323 const Obj_Entry **defobj_out, bool in_plt, DoneList *dlp)
2324{
2325 const Elf_Sym *symp;
2326 const Elf_Sym *def;
2327 const Obj_Entry *defobj;
2328 const Objlist_Entry *elm;
2329
2330 def = NULL;
2331 defobj = NULL;
2332 STAILQ_FOREACH(elm, objlist, link) {
2333 if (donelist_check(dlp, elm->obj))
2334 continue;
2335 if ((symp = symlook_obj(name, hash, elm->obj, in_plt)) != NULL) {
2336 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) {
2337 def = symp;
2338 defobj = elm->obj;
2339 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
2340 break;
2341 }
2342 }
2343 }
2344 if (def != NULL)
2345 *defobj_out = defobj;
2346 return def;
2347}
2348
2349/*
2350 * Search the symbol table of a single shared object for a symbol of
2351 * the given name. Returns a pointer to the symbol, or NULL if no
2352 * definition was found.
2353 *
2354 * The symbol's hash value is passed in for efficiency reasons; that
2355 * eliminates many recomputations of the hash value.
2356 */
2357const Elf_Sym *
2358symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj,
2359 bool in_plt)
2360{
2361 if (obj->buckets != NULL) {
2362 unsigned long symnum = obj->buckets[hash % obj->nbuckets];
2363
2364 while (symnum != STN_UNDEF) {
2365 const Elf_Sym *symp;
2366 const char *strp;
2367
2368 if (symnum >= obj->nchains)
2369 return NULL; /* Bad object */
2370 symp = obj->symtab + symnum;
2371 strp = obj->strtab + symp->st_name;
2372
2373 if (name[0] == strp[0] && strcmp(name, strp) == 0)
2374 return symp->st_shndx != SHN_UNDEF ||
2375 (!in_plt && symp->st_value != 0 &&
2376 ELF_ST_TYPE(symp->st_info) == STT_FUNC) ? symp : NULL;
2377
2378 symnum = obj->chains[symnum];
2379 }
2380 }
2381 return NULL;
2382}
2383
2384static void
2385trace_loaded_objects(Obj_Entry *obj)
2386{
8ca15ec8 2387 const char *fmt1, *fmt2, *fmt, *main_local;
984263bc
MD
2388 int c;
2389
8ca15ec8 2390 if ((main_local = _getenv_ld("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
984263bc
MD
2391 main_local = "";
2392
8ca15ec8 2393 if ((fmt1 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
984263bc
MD
2394 fmt1 = "\t%o => %p (%x)\n";
2395
8ca15ec8 2396 if ((fmt2 = _getenv_ld("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
984263bc
MD
2397 fmt2 = "\t%o (%x)\n";
2398
2399 for (; obj; obj = obj->next) {
2400 Needed_Entry *needed;
2401 char *name, *path;
2402 bool is_lib;
2403
2404 for (needed = obj->needed; needed; needed = needed->next) {
2405 if (needed->obj != NULL) {
2406 if (needed->obj->traced)
2407 continue;
2408 needed->obj->traced = true;
2409 path = needed->obj->path;
2410 } else
2411 path = "not found";
2412
2413 name = (char *)obj->strtab + needed->name;
2414 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
2415
2416 fmt = is_lib ? fmt1 : fmt2;
2417 while ((c = *fmt++) != '\0') {
2418 switch (c) {
2419 default:
2420 putchar(c);
2421 continue;
2422 case '\\':
2423 switch (c = *fmt) {
2424 case '\0':
2425 continue;
2426 case 'n':
2427 putchar('\n');
2428 break;
2429 case 't':
2430 putchar('\t');
2431 break;
2432 }
2433 break;
2434 case '%':
2435 switch (c = *fmt) {
2436 case '\0':
2437 continue;
2438 case '%':
2439 default:
2440 putchar(c);
2441 break;
2442 case 'A':
2443 printf("%s", main_local);
2444 break;
2445 case 'a':
2446 printf("%s", obj_main->path);
2447 break;
2448 case 'o':
2449 printf("%s", name);
2450 break;
2451#if 0
2452 case 'm':
2453 printf("%d", sodp->sod_major);
2454 break;
2455 case 'n':
2456 printf("%d", sodp->sod_minor);
2457 break;
2458#endif
2459 case 'p':
2460 printf("%s", path);
2461 break;
2462 case 'x':
2463 printf("%p", needed->obj ? needed->obj->mapbase : 0);
2464 break;
2465 }
2466 break;
2467 }
2468 ++fmt;
2469 }
2470 }
2471 }
2472}
2473
2474/*
2475 * Unload a dlopened object and its dependencies from memory and from
2476 * our data structures. It is assumed that the DAG rooted in the
2477 * object has already been unreferenced, and that the object has a
2478 * reference count of 0.
2479 */
2480static void
2481unload_object(Obj_Entry *root)
2482{
2483 Obj_Entry *obj;
2484 Obj_Entry **linkp;
2485
2486 assert(root->refcount == 0);
2487
2488 /*
2489 * Pass over the DAG removing unreferenced objects from
2490 * appropriate lists.
2491 */
2492 unlink_object(root);
2493
2494 /* Unmap all objects that are no longer referenced. */
2495 linkp = &obj_list->next;
2496 while ((obj = *linkp) != NULL) {
2497 if (obj->refcount == 0) {
2498 dbg("unloading \"%s\"", obj->path);
2499 munmap(obj->mapbase, obj->mapsize);
2500 linkmap_delete(obj);
2501 *linkp = obj->next;
2502 obj_count--;
2503 obj_free(obj);
2504 } else
2505 linkp = &obj->next;
2506 }
2507 obj_tail = linkp;
2508}
2509
2510static void
2511unlink_object(Obj_Entry *root)
2512{
2513 const Needed_Entry *needed;
2514 Objlist_Entry *elm;
2515
2516 if (root->refcount == 0) {
2517 /* Remove the object from the RTLD_GLOBAL list. */
2518 objlist_remove(&list_global, root);
2519
2520 /* Remove the object from all objects' DAG lists. */
2521 STAILQ_FOREACH(elm, &root->dagmembers , link)
2522 objlist_remove(&elm->obj->dldags, root);
2523 }
2524
2525 for (needed = root->needed; needed != NULL; needed = needed->next)
2526 if (needed->obj != NULL)
2527 unlink_object(needed->obj);
2528}
2529
2530static void
2531unref_dag(Obj_Entry *root)
2532{
2533 const Needed_Entry *needed;
2534
2535 if (root->refcount == 0)
2536 return;
2537 root->refcount--;
2538 if (root->refcount == 0)
2539 for (needed = root->needed; needed != NULL; needed = needed->next)
2540 if (needed->obj != NULL)
2541 unref_dag(needed->obj);
2542}
55b88cae
DX
2543
2544/*
2545 * Common code for MD __tls_get_addr().
2546 */
2547void *
bc633d63 2548tls_get_addr_common(void **dtvp, int index, size_t offset)
55b88cae
DX
2549{
2550 Elf_Addr* dtv = *dtvp;
2551
2552 /* Check dtv generation in case new modules have arrived */
2553 if (dtv[0] != tls_dtv_generation) {
2554 Elf_Addr* newdtv;
2555 int to_copy;
2556
2557 wlock_acquire();
2558
2559 newdtv = calloc(1, (tls_max_index + 2) * sizeof(Elf_Addr));
2560 to_copy = dtv[1];
2561 if (to_copy > tls_max_index)
2562 to_copy = tls_max_index;
2563 memcpy(&newdtv[2], &dtv[2], to_copy * sizeof(Elf_Addr));
2564 newdtv[0] = tls_dtv_generation;
2565 newdtv[1] = tls_max_index;
2566 free(dtv);
bc633d63 2567 *dtvp = newdtv;
55b88cae
DX
2568
2569 wlock_release();
55b88cae
DX
2570 }
2571
2572 /* Dynamically allocate module TLS if necessary */
2573 if (!dtv[index + 1]) {
2574 /* XXX
2575 * here we should avoid to be re-entered by signal handler
2576 * code, I assume wlock_acquire will masked all signals,
2577 * otherwise there is race and dead lock thread itself.
2578 */
2579 wlock_acquire();
2580 if (!dtv[index + 1])
2581 dtv[index + 1] = (Elf_Addr)allocate_module_tls(index);
2582 wlock_release();
2583 }
2584
2585 return (void*) (dtv[index + 1] + offset);
2586}
2587
9e2ee207 2588#if defined(RTLD_STATIC_TLS_VARIANT_II)
55b88cae
DX
2589
2590/*
bc633d63
MD
2591 * Allocate the static TLS area. Return a pointer to the TCB. The
2592 * static area is based on negative offsets relative to the tcb.
55b88cae 2593 */
bc633d63 2594struct tls_tcb *
f20fd431 2595allocate_tls(Obj_Entry *objs, struct tls_tcb *old_tcb)
55b88cae
DX
2596{
2597 Obj_Entry *obj;
bc633d63 2598 size_t data_size;
bc633d63
MD
2599 size_t dtv_size;
2600 struct tls_tcb *tcb;
2601 Elf_Addr *dtv, *old_dtv;
2602 Elf_Addr addr;
55b88cae
DX
2603 int i;
2604
bc633d63
MD
2605 /*
2606 * Allocate the new TCB. static TLS storage is placed just before the
2607 * TCB to support the %gs:OFFSET (negative offset) model.
2608 */
bc633d63
MD
2609 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
2610 ~RTLD_STATIC_TLS_ALIGN_MASK;
f20fd431 2611 tcb = malloc(data_size + sizeof(*tcb));
bc633d63 2612 tcb = (void *)((char *)tcb + data_size); /* actual tcb location */
55b88cae 2613
bc633d63
MD
2614 dtv_size = (tls_max_index + 2) * sizeof(Elf_Addr);
2615 dtv = malloc(dtv_size);
2616 bzero(dtv, dtv_size);
55b88cae 2617
9e2ee207
JS
2618#ifdef RTLD_TCB_HAS_SELF_POINTER
2619 tcb->tcb_self = tcb;
2620#endif
2621 tcb->tcb_dtv = dtv;
2622 tcb->tcb_pthread = NULL;
55b88cae
DX
2623
2624 dtv[0] = tls_dtv_generation;
2625 dtv[1] = tls_max_index;
2626
bc633d63
MD
2627 /*
2628 * If a template tcb is supplied, copy the TLS storage from the template
2629 * to the new tcb, otherwise create a pristine data set.
2630 */
2631 if (old_tcb) {
55b88cae
DX
2632 /*
2633 * Copy the static TLS block over whole.
2634 */
bc633d63 2635 memcpy((char *)tcb - data_size, (char *)old_tcb - data_size, data_size);
55b88cae
DX
2636
2637 /*
2638 * If any dynamic TLS blocks have been created tls_get_addr(),
2639 * move them over.
2640 */
9e2ee207 2641 old_dtv = old_tcb->tcb_dtv;
bc633d63
MD
2642 for (i = 0; i < old_dtv[1]; i++) {
2643 if (old_dtv[i+2] < (Elf_Addr)((char *)old_tcb - data_size) ||
2644 old_dtv[i+2] >= (Elf_Addr)((char *)old_tcb)
2645 ) {
2646 dtv[i + 2] = old_dtv[i + 2];
2647 old_dtv[i + 2] = 0;
55b88cae
DX
2648 }
2649 }
f20fd431 2650 free_tls(old_tcb);
55b88cae
DX
2651 } else {
2652 for (obj = objs; obj; obj = obj->next) {
2653 if (obj->tlsoffset) {
bc633d63
MD
2654 addr = (Elf_Addr)tcb - obj->tlsoffset;
2655 memset((void *)(addr + obj->tlsinitsize),
55b88cae
DX
2656 0, obj->tlssize - obj->tlsinitsize);
2657 if (obj->tlsinit)
2658 memcpy((void*) addr, obj->tlsinit, obj->tlsinitsize);
2659 dtv[obj->tlsindex + 1] = addr;
55b88cae
DX
2660 }
2661 }
2662 }
bc633d63 2663 return(tcb);
55b88cae
DX
2664}
2665
2666void
f20fd431 2667free_tls(struct tls_tcb *tcb)
bc633d63
MD
2668{
2669 Elf_Addr *dtv;
2670 int dtv_size, i;
2671 Elf_Addr tls_start, tls_end;
2672 size_t data_size;
2673
2674 data_size = (tls_static_space + RTLD_STATIC_TLS_ALIGN_MASK) &
2675 ~RTLD_STATIC_TLS_ALIGN_MASK;
9e2ee207 2676 dtv = tcb->tcb_dtv;
bc633d63
MD
2677 dtv_size = dtv[1];
2678 tls_end = (Elf_Addr)tcb;
2679 tls_start = (Elf_Addr)tcb - data_size;
2680 for (i = 0; i < dtv_size; i++) {
2681 if (dtv[i+2] != NULL && (dtv[i+2] < tls_start || dtv[i+2] > tls_end)) {
2682 free((void *)dtv[i+2]);
55b88cae
DX
2683 }
2684 }
bc633d63 2685 free((void *)tls_start);
55b88cae
DX
2686}
2687
9e2ee207
JS
2688#else
2689#error "Unsupported TLS layout"
55b88cae
DX
2690#endif
2691
2692/*
2693 * Allocate TLS block for module with given index.
2694 */
2695void *
2696allocate_module_tls(int index)
2697{
2698 Obj_Entry* obj;
2699 char* p;
2700
2701 for (obj = obj_list; obj; obj = obj->next) {
2702 if (obj->tlsindex == index)
2703 break;
2704 }
2705 if (!obj) {
2706 _rtld_error("Can't find module with TLS index %d", index);
2707 die();
2708 }
2709
2710 p = malloc(obj->tlssize);
2711 memcpy(p, obj->tlsinit, obj->tlsinitsize);
2712 memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
2713
2714 return p;
2715}
2716
2717bool
2718allocate_tls_offset(Obj_Entry *obj)
2719{
2720 size_t off;
2721
2722 if (obj->tls_done)
2723 return true;
2724
2725 if (obj->tlssize == 0) {
2726 obj->tls_done = true;
2727 return true;
2728 }
2729
2730 if (obj->tlsindex == 1)
2731 off = calculate_first_tls_offset(obj->tlssize, obj->tlsalign);
2732 else
2733 off = calculate_tls_offset(tls_last_offset, tls_last_size,
2734 obj->tlssize, obj->tlsalign);
2735
2736 /*
2737 * If we have already fixed the size of the static TLS block, we
2738 * must stay within that size. When allocating the static TLS, we
2739 * leave a small amount of space spare to be used for dynamically
2740 * loading modules which use static TLS.
2741 */
2742 if (tls_static_space) {
2743 if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
2744 return false;
2745 }
2746
2747 tls_last_offset = obj->tlsoffset = off;
2748 tls_last_size = obj->tlssize;
2749 obj->tls_done = true;
2750
2751 return true;
2752}
2753
2754void
2755free_tls_offset(Obj_Entry *obj)
2756{
9e2ee207 2757#ifdef RTLD_STATIC_TLS_VARIANT_II
55b88cae
DX
2758 /*
2759 * If we were the last thing to allocate out of the static TLS
2760 * block, we give our space back to the 'allocator'. This is a
2761 * simplistic workaround to allow libGL.so.1 to be loaded and
2762 * unloaded multiple times. We only handle the Variant II
2763 * mechanism for now - this really needs a proper allocator.
2764 */
2765 if (calculate_tls_end(obj->tlsoffset, obj->tlssize)
2766 == calculate_tls_end(tls_last_offset, tls_last_size)) {
2767 tls_last_offset -= obj->tlssize;
2768 tls_last_size = 0;
2769 }
2770#endif
2771}
2772
bc633d63 2773struct tls_tcb *
f20fd431 2774_rtld_allocate_tls(struct tls_tcb *old_tcb)
55b88cae 2775{
bc633d63 2776 struct tls_tcb *new_tcb;
55b88cae
DX
2777
2778 wlock_acquire();
f20fd431 2779 new_tcb = allocate_tls(obj_list, old_tcb);
55b88cae
DX
2780 wlock_release();
2781
bc633d63 2782 return (new_tcb);
55b88cae
DX
2783}
2784
2785void
f20fd431 2786_rtld_free_tls(struct tls_tcb *tcb)
55b88cae
DX
2787{
2788 wlock_acquire();
f20fd431 2789 free_tls(tcb);
55b88cae
DX
2790 wlock_release();
2791}
bc633d63 2792