20 #include "pthread_impl.h"
24 static char errbuf[128];
28 #if ULONG_MAX == 0xffffffff
29 typedef Elf32_Ehdr Ehdr;
30 typedef Elf32_Phdr Phdr;
31 typedef Elf32_Sym Sym;
32 #define R_TYPE(x) ((x)&255)
33 #define R_SYM(x) ((x)>>8)
35 typedef Elf64_Ehdr Ehdr;
36 typedef Elf64_Phdr Phdr;
37 typedef Elf64_Sym Sym;
38 #define R_TYPE(x) ((x)&0xffffffff)
39 #define R_SYM(x) ((x)>>32)
42 #define MAXP2(a,b) (-(-(a)&-(b)))
43 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
55 struct td_index *next;
62 struct dso *next, *prev;
81 struct dso **deps, *needed_by;
82 char *rpath_orig, *rpath;
84 size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
85 size_t relro_start, relro_end;
87 unsigned char *new_tls;
88 int new_dtv_idx, new_tls_idx;
89 struct td_index *td_index;
90 struct dso *fini_next;
110 REL_TLS, /* everything past here is TLS */
120 int __init_tp(void *);
121 void __init_libc(char **, char *);
123 const char *__libc_get_version(void);
125 static struct dso *head, *tail, *ldso, *fini_head;
126 static char *env_path, *sys_path;
127 static unsigned long long gencnt;
130 static int ldso_fail;
132 static jmp_buf *rtld_fail;
133 static pthread_rwlock_t lock;
134 static struct debug debug;
135 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
136 static size_t static_tls_cnt;
137 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
138 static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
140 struct debug *_dl_debug_addr = &debug;
145 static void decode_vec(size_t *v, size_t *a, size_t cnt)
147 memset(a, 0, cnt*sizeof(size_t));
148 for (; v[0]; v+=2) if (v[0]<cnt) {
154 static int search_vec(size_t *v, size_t *r, size_t key)
156 for (; v[0]!=key; v+=2)
162 static void error(const char *fmt, ...)
166 vsnprintf(errbuf, sizeof errbuf, fmt, ap);
168 if (runtime) longjmp(*rtld_fail, 1);
169 dprintf(2, "%s\n", errbuf);
173 static uint32_t sysv_hash(const char *s0)
175 const unsigned char *s = (void *)s0;
181 return h & 0xfffffff;
184 static uint32_t gnu_hash(const char *s0)
186 const unsigned char *s = (void *)s0;
187 uint_fast32_t h = 5381;
193 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
196 Sym *syms = dso->syms;
197 uint32_t *hashtab = dso->hashtab;
198 char *strings = dso->strings;
199 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
200 if ((!dso->versym || dso->versym[i] >= 0)
201 && (!strcmp(s, strings+syms[i].st_name)))
207 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
209 Sym *syms = dso->syms;
210 char *strings = dso->strings;
211 uint32_t *hashtab = dso->ghashtab;
212 uint32_t nbuckets = hashtab[0];
213 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
216 uint32_t i = buckets[h1 % nbuckets];
220 hashval = buckets + nbuckets + (i - hashtab[1]);
222 for (h1 |= 1; ; i++) {
224 if ((!dso->versym || dso->versym[i] >= 0)
225 && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
233 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
234 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
236 #ifndef ARCH_SYM_REJECT_UND
237 #define ARCH_SYM_REJECT_UND(s) 0
240 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
242 uint32_t h = 0, gh = 0;
243 struct symdef def = {0};
244 for (; dso; dso=dso->next) {
246 if (!dso->global) continue;
248 if (!gh) gh = gnu_hash(s);
249 sym = gnu_lookup(s, gh, dso);
251 if (!h) h = sysv_hash(s);
252 sym = sysv_lookup(s, h, dso);
256 if (need_def || (sym->st_info&0xf) == STT_TLS
257 || ARCH_SYM_REJECT_UND(sym))
260 if ((sym->st_info&0xf) != STT_TLS)
262 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
263 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
265 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
268 if (sym->st_info>>4 == STB_GLOBAL) break;
273 #define NO_INLINE_ADDEND (1<<REL_COPY | 1<<REL_GOT | 1<<REL_PLT)
275 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
277 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
279 unsigned char *base = dso->base;
280 Sym *syms = dso->syms;
281 char *strings = dso->strings;
293 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
294 astype = R_TYPE(rel[1]);
295 if (!astype) continue;
296 type = remap_rel(astype);
298 error("Error relocating %s: unsupported relocation type %d",
302 sym_index = R_SYM(rel[1]);
303 reloc_addr = (void *)(base + rel[0]);
305 sym = syms + sym_index;
306 name = strings + sym->st_name;
307 ctx = type==REL_COPY ? head->next : head;
308 def = find_sym(ctx, name, type==REL_PLT);
309 if (!def.sym && (sym->st_shndx != SHN_UNDEF
310 || sym->st_info>>4 != STB_WEAK)) {
311 error("Error relocating %s: %s: symbol not found",
321 addend = stride>2 ? rel[2]
322 : (1<<type & NO_INLINE_ADDEND) ? 0
325 sym_val = def.sym ? (size_t)def.dso->base+def.sym->st_value : 0;
326 tls_val = def.sym ? def.sym->st_value : 0;
330 addend -= (size_t)reloc_addr;
334 *reloc_addr = sym_val + addend;
337 *reloc_addr = (size_t)base + addend;
340 if (sym) *reloc_addr = sym_val + addend;
341 else *reloc_addr = (size_t)base + addend;
344 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
347 *(uint32_t *)reloc_addr = sym_val + addend
348 - (size_t)reloc_addr;
351 *reloc_addr = def.dso->tls_id;
354 *reloc_addr = tls_val + addend;
358 *reloc_addr = tls_val + def.dso->tls_offset + TPOFF_K + addend;
362 *reloc_addr = tls_val - def.dso->tls_offset + addend;
365 *reloc_addr = def.dso->tls_offset - tls_val + addend;
369 if (stride<3) addend = reloc_addr[1];
370 if (runtime && def.dso->tls_id >= static_tls_cnt) {
371 struct td_index *new = malloc(sizeof *new);
373 "Error relocating %s: cannot allocate TLSDESC for %s",
374 dso->name, sym ? name : "(local)" );
375 new->next = dso->td_index;
377 new->args[0] = def.dso->tls_id;
378 new->args[1] = tls_val + addend;
379 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
380 reloc_addr[1] = (size_t)new;
382 reloc_addr[0] = (size_t)__tlsdesc_static;
384 reloc_addr[1] = tls_val + def.dso->tls_offset
387 reloc_addr[1] = tls_val - def.dso->tls_offset
396 /* A huge hack: to make up for the wastefulness of shared libraries
397 * needing at least a page of dirty memory even if they have no global
398 * data, we reclaim the gaps at the beginning and end of writable maps
399 * and "donate" them to the heap by setting up minimal malloc
400 * structures and then freeing them. */
402 static void reclaim(struct dso *dso, size_t start, size_t end)
405 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
406 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
407 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
408 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
409 if (start>end || end-start < 4*sizeof(size_t)) return;
410 a = (size_t *)(dso->base + start);
411 z = (size_t *)(dso->base + end);
413 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
418 static void reclaim_gaps(struct dso *dso)
420 Phdr *ph = dso->phdr;
421 size_t phcnt = dso->phnum;
423 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
424 if (ph->p_type!=PT_LOAD) continue;
425 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
426 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
427 reclaim(dso, ph->p_vaddr+ph->p_memsz,
428 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
432 static void *map_library(int fd, struct dso *dso)
434 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
435 void *allocated_buf=0;
437 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
438 size_t this_min, this_max;
443 unsigned char *map=MAP_FAILED, *base;
448 ssize_t l = read(fd, buf, sizeof buf);
451 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
453 phsize = eh->e_phentsize * eh->e_phnum;
454 if (phsize > sizeof buf - sizeof *eh) {
455 allocated_buf = malloc(phsize);
456 if (!allocated_buf) return 0;
457 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
458 if (l < 0) goto error;
459 if (l != phsize) goto noexec;
460 ph = ph0 = allocated_buf;
461 } else if (eh->e_phoff + phsize > l) {
462 l = pread(fd, buf+1, phsize, eh->e_phoff);
463 if (l < 0) goto error;
464 if (l != phsize) goto noexec;
465 ph = ph0 = (void *)(buf + 1);
467 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
469 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
470 if (ph->p_type == PT_DYNAMIC) {
472 } else if (ph->p_type == PT_TLS) {
473 tls_image = ph->p_vaddr;
474 dso->tls_align = ph->p_align;
475 dso->tls_len = ph->p_filesz;
476 dso->tls_size = ph->p_memsz;
477 } else if (ph->p_type == PT_GNU_RELRO) {
478 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
479 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
481 if (ph->p_type != PT_LOAD) continue;
482 if (ph->p_vaddr < addr_min) {
483 addr_min = ph->p_vaddr;
484 off_start = ph->p_offset;
485 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
486 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
487 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
489 if (ph->p_vaddr+ph->p_memsz > addr_max) {
490 addr_max = ph->p_vaddr+ph->p_memsz;
493 if (!dyn) goto noexec;
494 addr_max += PAGE_SIZE-1;
495 addr_max &= -PAGE_SIZE;
496 addr_min &= -PAGE_SIZE;
497 off_start &= -PAGE_SIZE;
498 map_len = addr_max - addr_min + off_start;
499 /* The first time, we map too much, possibly even more than
500 * the length of the file. This is okay because we will not
501 * use the invalid part; we just need to reserve the right
502 * amount of virtual address space to map over later. */
503 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
504 if (map==MAP_FAILED) goto error;
505 /* If the loaded file is not relocatable and the requested address is
506 * not available, then the load operation must fail. */
507 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
511 base = map - addr_min;
514 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
515 if (ph->p_type != PT_LOAD) continue;
516 /* Check if the programs headers are in this load segment, and
517 * if so, record the address for use by dl_iterate_phdr. */
518 if (!dso->phdr && eh->e_phoff >= ph->p_offset
519 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
520 dso->phdr = (void *)(base + ph->p_vaddr
521 + (eh->e_phoff-ph->p_offset));
522 dso->phnum = eh->e_phnum;
523 dso->phentsize = eh->e_phentsize;
525 /* Reuse the existing mapping for the lowest-address LOAD */
526 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
527 this_min = ph->p_vaddr & -PAGE_SIZE;
528 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
529 off_start = ph->p_offset & -PAGE_SIZE;
530 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
531 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
532 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
533 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
535 if (ph->p_memsz > ph->p_filesz) {
536 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
537 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
538 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
539 if (pgbrk-(size_t)base < this_max && mmap((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED)
543 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
544 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
545 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
550 dso->map_len = map_len;
552 dso->dynv = (void *)(base+dyn);
553 if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
554 if (!runtime) reclaim_gaps(dso);
560 if (map!=MAP_FAILED) munmap(map, map_len);
565 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
570 s += strspn(s, ":\n");
571 l = strcspn(s, ":\n");
572 if (l-1 >= INT_MAX) return -1;
573 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
575 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
580 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
583 const char *s, *t, *origin;
585 if (p->rpath) return 0;
586 if (!p->rpath_orig) return -1;
587 if (!strchr(p->rpath_orig, '$')) {
588 p->rpath = p->rpath_orig;
593 while ((t=strchr(s, '$'))) {
594 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
599 if (n > SSIZE_MAX/PATH_MAX) return -1;
601 if (p->kernel_mapped) {
602 /* $ORIGIN searches cannot be performed for the main program
603 * when it is suid/sgid/AT_SECURE. This is because the
604 * pathname is under the control of the caller of execve.
605 * For libraries, however, $ORIGIN can be processed safely
606 * since the library's pathname came from a trusted source
607 * (either system paths or a call to dlopen). */
610 l = readlink("/proc/self/exe", buf, buf_size);
618 t = strrchr(origin, '/');
619 l = t ? t-origin : 0;
620 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
621 if (!p->rpath) return -1;
625 while ((t=strchr(s, '$'))) {
628 memcpy(d, origin, l);
630 /* It was determined previously that the '$' is followed
631 * either by "ORIGIN" or "{ORIGIN}". */
632 s = t + 7 + 2*(t[1]=='{');
638 static void decode_dyn(struct dso *p)
640 size_t dyn[DYN_CNT] = {0};
641 decode_vec(p->dynv, dyn, DYN_CNT);
642 p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
643 p->strings = (void *)(p->base + dyn[DT_STRTAB]);
644 if (dyn[0]&(1<<DT_HASH))
645 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
646 if (dyn[0]&(1<<DT_RPATH))
647 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
648 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
649 p->ghashtab = (void *)(p->base + *dyn);
650 if (search_vec(p->dynv, dyn, DT_VERSYM))
651 p->versym = (void *)(p->base + *dyn);
654 static struct dso *load_library(const char *name, struct dso *needed_by)
656 char buf[2*NAME_MAX+2];
657 const char *pathname;
659 struct dso *p, temp_dso = {0};
666 /* Catch and block attempts to reload the implementation itself */
667 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
668 static const char *rp, reserved[] =
669 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
670 char *z = strchr(name, '.');
673 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
676 /* Track which names have been resolved
677 * and only report each one once. */
678 static unsigned reported;
679 unsigned mask = 1U<<(rp-reserved);
680 if (!(reported & mask)) {
682 dprintf(1, "\t%s => %s (%p)\n",
691 if (!strcmp(name, ldso->name)) is_self = 1;
696 tail = ldso->next ? ldso->next : ldso;
700 if (strchr(name, '/')) {
702 fd = open(name, O_RDONLY|O_CLOEXEC);
704 /* Search for the name to see if it's already loaded */
705 for (p=head->next; p; p=p->next) {
706 if (p->shortname && !strcmp(p->shortname, name)) {
711 if (strlen(name) > NAME_MAX) return 0;
713 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
714 for (p=needed_by; fd < 0 && p; p=p->needed_by)
715 if (!fixup_rpath(p, buf, sizeof buf))
716 fd = path_open(name, p->rpath, buf, sizeof buf);
721 if (ldso->name[0]=='/') {
723 for (s=t=z=ldso->name; *s; s++)
724 if (*s=='/') z=t, t=s;
725 prefix_len = z-ldso->name;
726 if (prefix_len < PATH_MAX)
733 char etc_ldso_path[prefix_len + 1
734 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
735 snprintf(etc_ldso_path, sizeof etc_ldso_path,
736 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
737 (int)prefix_len, prefix);
738 FILE *f = fopen(etc_ldso_path, "rbe");
740 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
745 } else if (errno != ENOENT) {
749 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
750 fd = path_open(name, sys_path, buf, sizeof buf);
754 if (fd < 0) return 0;
755 if (fstat(fd, &st) < 0) {
759 for (p=head->next; p; p=p->next) {
760 if (p->dev == st.st_dev && p->ino == st.st_ino) {
761 /* If this library was previously loaded with a
762 * pathname but a search found the same inode,
763 * setup its shortname so it can be found by name. */
764 if (!p->shortname && pathname != name)
765 p->shortname = strrchr(p->name, '/')+1;
771 map = noload ? 0 : map_library(fd, &temp_dso);
775 /* Allocate storage for the new DSO. When there is TLS, this
776 * storage must include a reservation for all pre-existing
777 * threads to obtain copies of both the new TLS, and an
778 * extended DTV capable of storing an additional slot for
779 * the newly-loaded DSO. */
780 alloc_size = sizeof *p + strlen(pathname) + 1;
781 if (runtime && temp_dso.tls_image) {
782 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
783 + sizeof(void *) * (tls_cnt+3);
784 n_th = libc.threads_minus_1 + 1;
785 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
786 else alloc_size += n_th * per_th;
788 p = calloc(1, alloc_size);
790 munmap(map, temp_dso.map_len);
793 memcpy(p, &temp_dso, sizeof temp_dso);
798 p->needed_by = needed_by;
800 strcpy(p->name, pathname);
801 /* Add a shortname only if name arg was not an explicit pathname. */
802 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
804 if (runtime && !libc.has_thread_pointer) {
805 munmap(map, p->map_len);
810 p->tls_id = ++tls_cnt;
811 tls_align = MAXP2(tls_align, p->tls_align);
813 p->tls_offset = tls_offset + ( (tls_align-1) &
814 -(tls_offset + (uintptr_t)p->tls_image) );
815 tls_offset += p->tls_size;
817 tls_offset += p->tls_size + p->tls_align - 1;
818 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
820 p->tls_offset = tls_offset;
822 p->new_dtv = (void *)(-sizeof(size_t) &
823 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
824 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
831 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
836 static void load_deps(struct dso *p)
839 struct dso ***deps = &p->deps, **tmp, *dep;
840 for (; p; p=p->next) {
841 for (i=0; p->dynv[i]; i+=2) {
842 if (p->dynv[i] != DT_NEEDED) continue;
843 dep = load_library(p->strings + p->dynv[i+1], p);
845 error("Error loading shared library %s: %m (needed by %s)",
846 p->strings + p->dynv[i+1], p->name);
850 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
851 if (!tmp) longjmp(*rtld_fail, 1);
860 static void load_preload(char *s)
865 for ( ; *s && isspace(*s); s++);
866 for (z=s; *z && !isspace(*z); z++);
874 static void make_global(struct dso *p)
876 for (; p; p=p->next) p->global = 1;
879 static void reloc_all(struct dso *p)
881 size_t dyn[DYN_CNT] = {0};
882 for (; p; p=p->next) {
883 if (p->relocated) continue;
884 decode_vec(p->dynv, dyn, DYN_CNT);
885 #ifdef NEED_ARCH_RELOCS
886 do_arch_relocs(p, head);
888 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
889 2+(dyn[DT_PLTREL]==DT_RELA));
890 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
891 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
893 if (p->relro_start != p->relro_end &&
894 mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) {
895 error("Error relocating %s: RELRO protection failed: %m",
903 static void kernel_mapped_dso(struct dso *p)
905 size_t min_addr = -1, max_addr = 0, cnt;
907 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
908 if (ph->p_type == PT_DYNAMIC) {
909 p->dynv = (void *)(p->base + ph->p_vaddr);
910 } else if (ph->p_type == PT_GNU_RELRO) {
911 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
912 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
914 if (ph->p_type != PT_LOAD) continue;
915 if (ph->p_vaddr < min_addr)
916 min_addr = ph->p_vaddr;
917 if (ph->p_vaddr+ph->p_memsz > max_addr)
918 max_addr = ph->p_vaddr+ph->p_memsz;
920 min_addr &= -PAGE_SIZE;
921 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
922 p->map = p->base + min_addr;
923 p->map_len = max_addr - min_addr;
924 p->kernel_mapped = 1;
927 static void do_fini()
930 size_t dyn[DYN_CNT] = {0};
931 for (p=fini_head; p; p=p->fini_next) {
932 if (!p->constructed) continue;
933 decode_vec(p->dynv, dyn, DYN_CNT);
934 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
935 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
936 size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
937 while (n--) ((void (*)(void))*--fn)();
939 #ifndef NO_LEGACY_INITFINI
940 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
941 ((void (*)(void))(p->base + dyn[DT_FINI]))();
946 static void do_init_fini(struct dso *p)
948 size_t dyn[DYN_CNT] = {0};
949 int need_locking = libc.threads_minus_1;
950 /* Allow recursive calls that arise when a library calls
951 * dlopen from one of its constructors, but block any
952 * other threads until all ctors have finished. */
953 if (need_locking) pthread_mutex_lock(&init_fini_lock);
954 for (; p; p=p->prev) {
955 if (p->constructed) continue;
957 decode_vec(p->dynv, dyn, DYN_CNT);
958 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
959 p->fini_next = fini_head;
962 #ifndef NO_LEGACY_INITFINI
963 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
964 ((void (*)(void))(p->base + dyn[DT_INIT]))();
966 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
967 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
968 size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
969 while (n--) ((void (*)(void))*fn++)();
971 if (!need_locking && libc.threads_minus_1) {
973 pthread_mutex_lock(&init_fini_lock);
976 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
979 void _dl_debug_state(void)
985 pthread_t self = __pthread_self();
987 for (p=head; p; p=p->next) {
988 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
989 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
990 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
991 p->tls_size - p->tls_len);
992 if (p->tls_id == (size_t)self->dtv[0]) break;
996 void *__copy_tls(unsigned char *mem)
1001 void **dtv = (void *)mem;
1002 dtv[0] = (void *)tls_cnt;
1004 td = (void *)(dtv+1);
1010 mem += sizeof(void *) * (tls_cnt+1);
1011 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
1012 td = (pthread_t)mem;
1013 mem += sizeof(struct pthread);
1015 for (p=head; p; p=p->next) {
1016 if (!p->tls_id) continue;
1017 dtv[p->tls_id] = mem + p->tls_offset;
1018 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1021 mem += libc.tls_size - sizeof(struct pthread);
1022 mem -= (uintptr_t)mem & (tls_align-1);
1023 td = (pthread_t)mem;
1025 for (p=head; p; p=p->next) {
1026 if (!p->tls_id) continue;
1027 dtv[p->tls_id] = mem - p->tls_offset;
1028 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1035 void *__tls_get_new(size_t *v)
1037 pthread_t self = __pthread_self();
1039 /* Block signals to make accessing new TLS async-signal-safe */
1041 __block_all_sigs(&set);
1042 if (v[0]<=(size_t)self->dtv[0]) {
1043 __restore_sigs(&set);
1044 return (char *)self->dtv[v[0]]+v[1];
1047 /* This is safe without any locks held because, if the caller
1048 * is able to request the Nth entry of the DTV, the DSO list
1049 * must be valid at least that far out and it was synchronized
1050 * at program startup or by an already-completed call to dlopen. */
1052 for (p=head; p->tls_id != v[0]; p=p->next);
1054 /* Get new DTV space from new DSO if needed */
1055 if (v[0] > (size_t)self->dtv[0]) {
1056 void **newdtv = p->new_dtv +
1057 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1058 memcpy(newdtv, self->dtv,
1059 ((size_t)self->dtv[0]+1) * sizeof(void *));
1060 newdtv[0] = (void *)v[0];
1064 /* Get new TLS memory from all new DSOs up to the requested one */
1066 for (p=head; ; p=p->next) {
1067 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1068 mem = p->new_tls + (p->tls_size + p->tls_align)
1069 * a_fetch_add(&p->new_tls_idx,1);
1070 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
1072 self->dtv[p->tls_id] = mem;
1073 memcpy(mem, p->tls_image, p->tls_len);
1074 if (p->tls_id == v[0]) break;
1076 __restore_sigs(&set);
1080 static void update_tls_size()
1082 libc.tls_size = ALIGN(
1083 (1+tls_cnt) * sizeof(void *) +
1085 sizeof(struct pthread) +
1090 void *__dynlink(int argc, char **argv)
1092 size_t aux[AUX_CNT] = {0};
1096 static struct dso builtin_dsos[3];
1097 struct dso *const app = builtin_dsos+0;
1098 struct dso *const lib = builtin_dsos+1;
1099 struct dso *const vdso = builtin_dsos+2;
1100 char *env_preload=0;
1103 char **envp = argv+argc+1;
1106 /* Find aux vector just past environ[] */
1107 for (i=argc+1; argv[i]; i++)
1108 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
1109 env_path = argv[i]+16;
1110 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
1111 env_preload = argv[i]+11;
1112 auxv = (void *)(argv+i+1);
1114 decode_vec(auxv, aux, AUX_CNT);
1116 /* Only trust user/env if kernel says we're not suid/sgid */
1117 if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1118 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
1123 libc.page_size = aux[AT_PAGESZ];
1125 /* If the dynamic linker was invoked as a program itself, AT_BASE
1126 * will not be set. In that case, we assume the base address is
1127 * the start of the page containing the PHDRs; I don't know any
1128 * better approach... */
1129 if (!aux[AT_BASE]) {
1130 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
1131 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
1134 /* The dynamic linker load address is passed by the kernel
1135 * in the AUX vector, so this is easy. */
1136 lib->base = (void *)aux[AT_BASE];
1137 lib->name = lib->shortname = "libc.so";
1139 ehdr = (void *)lib->base;
1140 lib->phnum = ehdr->e_phnum;
1141 lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1142 lib->phentsize = ehdr->e_phentsize;
1143 kernel_mapped_dso(lib);
1147 size_t interp_off = 0;
1148 size_t tls_image = 0;
1149 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1150 app->phdr = phdr = (void *)aux[AT_PHDR];
1151 app->phnum = aux[AT_PHNUM];
1152 app->phentsize = aux[AT_PHENT];
1153 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1154 if (phdr->p_type == PT_PHDR)
1155 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1156 else if (phdr->p_type == PT_INTERP)
1157 interp_off = (size_t)phdr->p_vaddr;
1158 else if (phdr->p_type == PT_TLS) {
1159 tls_image = phdr->p_vaddr;
1160 app->tls_len = phdr->p_filesz;
1161 app->tls_size = phdr->p_memsz;
1162 app->tls_align = phdr->p_align;
1165 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1166 if (interp_off) lib->name = (char *)app->base + interp_off;
1167 if ((aux[0] & (1UL<<AT_EXECFN))
1168 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1169 app->name = (char *)aux[AT_EXECFN];
1171 app->name = argv[0];
1172 kernel_mapped_dso(app);
1175 char *ldname = argv[0];
1176 size_t l = strlen(ldname);
1177 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1178 *argv++ = (void *)-1;
1179 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1180 char *opt = argv[0]+2;
1181 *argv++ = (void *)-1;
1184 } else if (!memcmp(opt, "list", 5)) {
1186 } else if (!memcmp(opt, "library-path", 12)) {
1187 if (opt[12]=='=') env_path = opt+13;
1188 else if (opt[12]) *argv = 0;
1189 else if (*argv) env_path = *argv++;
1190 } else if (!memcmp(opt, "preload", 7)) {
1191 if (opt[7]=='=') env_preload = opt+8;
1192 else if (opt[7]) *argv = 0;
1193 else if (*argv) env_preload = *argv++;
1197 argv[-1] = (void *)-1;
1200 dprintf(2, "musl libc\n"
1202 "Dynamic Program Loader\n"
1203 "Usage: %s [options] [--] pathname%s\n",
1204 __libc_get_version(), ldname,
1205 ldd_mode ? "" : " [args]");
1208 fd = open(argv[0], O_RDONLY);
1210 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1214 ehdr = (void *)map_library(fd, app);
1216 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1222 app->name = argv[0];
1223 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1224 /* Find the name that would have been used for the dynamic
1225 * linker had ldd not taken its place. */
1227 for (i=0; i<app->phnum; i++) {
1228 if (app->phdr[i].p_type == PT_INTERP)
1229 lib->name = (void *)(app->base
1230 + app->phdr[i].p_vaddr);
1232 dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1235 if (app->tls_size) {
1236 app->tls_id = tls_cnt = 1;
1238 app->tls_offset = 0;
1239 tls_offset = app->tls_size
1240 + ( -((uintptr_t)app->tls_image + app->tls_size)
1241 & (app->tls_align-1) );
1243 tls_offset = app->tls_offset = app->tls_size
1244 + ( -((uintptr_t)app->tls_image + app->tls_size)
1245 & (app->tls_align-1) );
1247 tls_align = MAXP2(tls_align, app->tls_align);
1252 /* Attach to vdso, if provided by the kernel */
1253 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1254 ehdr = (void *)vdso_base;
1255 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1256 vdso->phnum = ehdr->e_phnum;
1257 vdso->phentsize = ehdr->e_phentsize;
1258 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1259 if (phdr->p_type == PT_DYNAMIC)
1260 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1261 if (phdr->p_type == PT_LOAD)
1262 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1265 vdso->shortname = "linux-gate.so.1";
1272 /* Initial dso chain consists only of the app. We temporarily
1273 * append the dynamic linker/libc so we can relocate it, then
1274 * restore the initial chain in preparation for loading third
1275 * party libraries (preload/needed). */
1282 /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1284 /* Donate unused parts of app and library mapping to malloc */
1288 /* Load preload/needed libraries, add their symbols to the global
1289 * namespace, and perform all remaining relocations. The main
1290 * program must be relocated LAST since it may contain copy
1291 * relocations which depend on libraries' relocations. */
1292 if (env_preload) load_preload(env_preload);
1296 #ifndef DYNAMIC_IS_RO
1297 for (i=0; app->dynv[i]; i+=2)
1298 if (app->dynv[i]==DT_DEBUG)
1299 app->dynv[i+1] = (size_t)&debug;
1302 reloc_all(app->next);
1306 if (libc.tls_size > sizeof builtin_tls) {
1307 initial_tls = calloc(libc.tls_size, 1);
1309 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1310 argv[0], libc.tls_size);
1314 initial_tls = builtin_tls;
1316 if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
1317 dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
1320 static_tls_cnt = tls_cnt;
1322 if (ldso_fail) _exit(127);
1323 if (ldd_mode) _exit(0);
1325 /* Switch to runtime mode: any further failures in the dynamic
1326 * linker are a reportable failure rather than a fatal startup
1327 * error. If the dynamic loader (dlopen) will not be used, free
1328 * all memory used by the dynamic linker. */
1332 debug.bp = _dl_debug_state;
1334 debug.base = lib->base;
1338 __init_libc(envp, argv[0]);
1343 return (void *)aux[AT_ENTRY];
1346 void *dlopen(const char *file, int mode)
1348 struct dso *volatile p, *orig_tail, *next;
1349 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1354 if (!file) return head;
1356 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1357 pthread_rwlock_wrlock(&lock);
1361 orig_tls_cnt = tls_cnt;
1362 orig_tls_offset = tls_offset;
1363 orig_tls_align = tls_align;
1365 noload = mode & RTLD_NOLOAD;
1368 if (setjmp(*rtld_fail)) {
1369 /* Clean up anything new that was (partially) loaded */
1370 if (p && p->deps) for (i=0; p->deps[i]; i++)
1371 if (p->deps[i]->global < 0)
1372 p->deps[i]->global = 0;
1373 for (p=orig_tail->next; p; p=next) {
1375 munmap(p->map, p->map_len);
1376 while (p->td_index) {
1377 void *tmp = p->td_index->next;
1384 tls_cnt = orig_tls_cnt;
1385 tls_offset = orig_tls_offset;
1386 tls_align = orig_tls_align;
1392 } else p = load_library(file, head);
1395 snprintf(errbuf, sizeof errbuf, noload ?
1396 "Library %s is not already loaded" :
1397 "Error loading shared library %s: %m",
1403 /* First load handling */
1406 if (p->deps) for (i=0; p->deps[i]; i++)
1407 if (!p->deps[i]->global)
1408 p->deps[i]->global = -1;
1409 if (!p->global) p->global = -1;
1411 if (p->deps) for (i=0; p->deps[i]; i++)
1412 if (p->deps[i]->global < 0)
1413 p->deps[i]->global = 0;
1414 if (p->global < 0) p->global = 0;
1417 if (mode & RTLD_GLOBAL) {
1418 if (p->deps) for (i=0; p->deps[i]; i++)
1419 p->deps[i]->global = 1;
1429 pthread_rwlock_unlock(&lock);
1430 if (p) do_init_fini(orig_tail);
1431 pthread_setcancelstate(cs, 0);
1435 static int invalid_dso_handle(void *h)
1438 for (p=head; p; p=p->next) if (h==p) return 0;
1439 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1444 void *__tls_get_addr(size_t *);
1446 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1449 uint32_t h = 0, gh = 0;
1451 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1452 if (p == RTLD_DEFAULT) {
1454 } else if (p == RTLD_NEXT) {
1455 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1459 struct symdef def = find_sym(p, s, 0);
1460 if (!def.sym) goto failed;
1461 if ((def.sym->st_info&0xf) == STT_TLS)
1462 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1463 return def.dso->base + def.sym->st_value;
1465 if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1469 sym = gnu_lookup(s, gh, p);
1472 sym = sysv_lookup(s, h, p);
1474 if (sym && (sym->st_info&0xf) == STT_TLS)
1475 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1476 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1477 return p->base + sym->st_value;
1478 if (p->deps) for (i=0; p->deps[i]; i++) {
1479 if (p->deps[i]->ghashtab) {
1480 if (!gh) gh = gnu_hash(s);
1481 sym = gnu_lookup(s, gh, p->deps[i]);
1483 if (!h) h = sysv_hash(s);
1484 sym = sysv_lookup(s, h, p->deps[i]);
1486 if (sym && (sym->st_info&0xf) == STT_TLS)
1487 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1488 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1489 return p->deps[i]->base + sym->st_value;
1493 snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1497 int __dladdr(const void *addr, Dl_info *info)
1507 pthread_rwlock_rdlock(&lock);
1508 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1509 pthread_rwlock_unlock(&lock);
1514 strings = p->strings;
1516 nsym = p->hashtab[1];
1520 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1521 sym += p->ghashtab[1];
1522 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1523 if (buckets[i] > nsym)
1527 nsym -= p->ghashtab[1];
1528 hashval = buckets + p->ghashtab[0] + nsym;
1530 while (!(*hashval++ & 1));
1534 for (; nsym; nsym--, sym++) {
1536 && (1<<(sym->st_info&0xf) & OK_TYPES)
1537 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1538 void *symaddr = p->base + sym->st_value;
1539 if (symaddr > addr || symaddr < best)
1542 bestname = strings + sym->st_name;
1543 if (addr == symaddr)
1548 if (!best) return 0;
1550 info->dli_fname = p->name;
1551 info->dli_fbase = p->base;
1552 info->dli_sname = bestname;
1553 info->dli_saddr = best;
1558 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1561 pthread_rwlock_rdlock(&lock);
1562 res = do_dlsym(p, s, ra);
1563 pthread_rwlock_unlock(&lock);
1567 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1569 struct dso *current;
1570 struct dl_phdr_info info;
1572 for(current = head; current;) {
1573 info.dlpi_addr = (uintptr_t)current->base;
1574 info.dlpi_name = current->name;
1575 info.dlpi_phdr = current->phdr;
1576 info.dlpi_phnum = current->phnum;
1577 info.dlpi_adds = gencnt;
1579 info.dlpi_tls_modid = current->tls_id;
1580 info.dlpi_tls_data = current->tls_image;
1582 ret = (callback)(&info, sizeof (info), data);
1584 if (ret != 0) break;
1586 pthread_rwlock_rdlock(&lock);
1587 current = current->next;
1588 pthread_rwlock_unlock(&lock);
1593 static int invalid_dso_handle(void *h)
1595 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1599 void *dlopen(const char *file, int mode)
1603 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1607 int __dladdr (const void *addr, Dl_info *info)
1613 int __dlinfo(void *dso, int req, void *res)
1615 if (invalid_dso_handle(dso)) return -1;
1616 if (req != RTLD_DI_LINKMAP) {
1617 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1621 *(struct link_map **)res = dso;
1627 if (!errflag) return 0;
1632 int dlclose(void *p)
1634 return invalid_dso_handle(p);