21 #include "pthread_impl.h"
25 static char errbuf[128];
29 #if ULONG_MAX == 0xffffffff
30 typedef Elf32_Ehdr Ehdr;
31 typedef Elf32_Phdr Phdr;
32 typedef Elf32_Sym Sym;
33 #define R_TYPE(x) ((x)&255)
34 #define R_SYM(x) ((x)>>8)
36 typedef Elf64_Ehdr Ehdr;
37 typedef Elf64_Phdr Phdr;
38 typedef Elf64_Sym Sym;
39 #define R_TYPE(x) ((x)&0xffffffff)
40 #define R_SYM(x) ((x)>>32)
43 #define MAXP2(a,b) (-(-(a)&-(b)))
44 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
58 struct dso *next, *prev;
76 size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
78 unsigned char *new_tls;
79 int new_dtv_idx, new_tls_idx;
80 struct dso *fini_next;
92 void __init_ssp(size_t *);
93 void *__install_initial_tls(void *);
94 void __init_libc(char **, char *);
96 static struct dso *head, *tail, *ldso, *fini_head;
97 static char *env_path, *sys_path, *r_path;
98 static unsigned long long gencnt;
102 static int ldso_fail;
104 static jmp_buf *rtld_fail;
105 static pthread_rwlock_t lock;
106 static struct debug debug;
107 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
108 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
110 struct debug *_dl_debug_addr = &debug;
115 static void decode_vec(size_t *v, size_t *a, size_t cnt)
117 memset(a, 0, cnt*sizeof(size_t));
118 for (; v[0]; v+=2) if (v[0]<cnt) {
124 static int search_vec(size_t *v, size_t *r, size_t key)
126 for (; v[0]!=key; v+=2)
132 static uint32_t sysv_hash(const char *s0)
134 const unsigned char *s = (void *)s0;
140 return h & 0xfffffff;
143 static uint32_t gnu_hash(const char *s0)
145 const unsigned char *s = (void *)s0;
146 uint_fast32_t h = 5381;
152 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
155 Sym *syms = dso->syms;
156 uint32_t *hashtab = dso->hashtab;
157 char *strings = dso->strings;
158 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
159 if (!strcmp(s, strings+syms[i].st_name))
165 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
169 uint32_t *hashtab = dso->ghashtab;
170 uint32_t nbuckets = hashtab[0];
171 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
174 uint32_t n = buckets[h1 % nbuckets];
178 strings = dso->strings;
180 hashval = buckets + nbuckets + (n - hashtab[1]);
182 for (h1 |= 1; ; sym++) {
184 if ((h1 == (h2|1)) && !strcmp(s, strings + sym->st_name))
192 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
193 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
195 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
197 uint32_t h = 0, gh = 0;
198 struct symdef def = {0};
201 if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
204 if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
206 for (; dso; dso=dso->next) {
208 if (!dso->global) continue;
210 if (!gh) gh = gnu_hash(s);
211 sym = gnu_lookup(s, gh, dso);
213 if (!h) h = sysv_hash(s);
214 sym = sysv_lookup(s, h, dso);
218 if (need_def || (sym->st_info&0xf) == STT_TLS)
221 if ((sym->st_info&0xf) != STT_TLS)
223 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
224 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
226 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
229 if (sym->st_info>>4 == STB_GLOBAL) break;
234 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
236 unsigned char *base = dso->base;
237 Sym *syms = dso->syms;
238 char *strings = dso->strings;
246 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
247 type = R_TYPE(rel[1]);
248 sym_index = R_SYM(rel[1]);
250 sym = syms + sym_index;
251 name = strings + sym->st_name;
252 ctx = IS_COPY(type) ? head->next : head;
253 def = find_sym(ctx, name, IS_PLT(type));
254 if (!def.sym && sym->st_info>>4 != STB_WEAK) {
255 snprintf(errbuf, sizeof errbuf,
256 "Error relocating %s: %s: symbol not found",
258 if (runtime) longjmp(*rtld_fail, 1);
259 dprintf(2, "%s\n", errbuf);
268 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
269 stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
270 def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
274 /* A huge hack: to make up for the wastefulness of shared libraries
275 * needing at least a page of dirty memory even if they have no global
276 * data, we reclaim the gaps at the beginning and end of writable maps
277 * and "donate" them to the heap by setting up minimal malloc
278 * structures and then freeing them. */
280 static void reclaim(unsigned char *base, size_t start, size_t end)
283 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
284 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
285 if (start>end || end-start < 4*sizeof(size_t)) return;
286 a = (size_t *)(base + start);
287 z = (size_t *)(base + end);
289 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
294 static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
296 for (; phcnt--; ph=(void *)((char *)ph+phent)) {
297 if (ph->p_type!=PT_LOAD) continue;
298 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
299 reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
300 reclaim(base, ph->p_vaddr+ph->p_memsz,
301 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
305 static void *map_library(int fd, struct dso *dso)
307 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
309 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
310 size_t this_min, this_max;
315 unsigned char *map, *base;
320 ssize_t l = read(fd, buf, sizeof buf);
321 if (l<sizeof *eh) return 0;
323 phsize = eh->e_phentsize * eh->e_phnum;
324 if (phsize + sizeof *eh > l) return 0;
325 if (eh->e_phoff + phsize > l) {
326 l = pread(fd, buf+1, phsize, eh->e_phoff);
327 if (l != phsize) return 0;
328 ph = ph0 = (void *)(buf + 1);
330 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
332 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
333 if (ph->p_type == PT_DYNAMIC)
335 if (ph->p_type == PT_TLS) {
336 tls_image = ph->p_vaddr;
337 dso->tls_align = ph->p_align;
338 dso->tls_len = ph->p_filesz;
339 dso->tls_size = ph->p_memsz;
341 if (ph->p_type != PT_LOAD) continue;
342 if (ph->p_vaddr < addr_min) {
343 addr_min = ph->p_vaddr;
344 off_start = ph->p_offset;
345 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
346 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
347 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
349 if (ph->p_vaddr+ph->p_memsz > addr_max) {
350 addr_max = ph->p_vaddr+ph->p_memsz;
354 addr_max += PAGE_SIZE-1;
355 addr_max &= -PAGE_SIZE;
356 addr_min &= -PAGE_SIZE;
357 off_start &= -PAGE_SIZE;
358 map_len = addr_max - addr_min + off_start;
359 /* The first time, we map too much, possibly even more than
360 * the length of the file. This is okay because we will not
361 * use the invalid part; we just need to reserve the right
362 * amount of virtual address space to map over later. */
363 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
364 if (map==MAP_FAILED) return 0;
365 base = map - addr_min;
368 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
369 if (ph->p_type != PT_LOAD) continue;
370 /* Check if the programs headers are in this load segment, and
371 * if so, record the address for use by dl_iterate_phdr. */
372 if (!dso->phdr && eh->e_phoff >= ph->p_offset
373 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
374 dso->phdr = (void *)(base + ph->p_vaddr
375 + (eh->e_phoff-ph->p_offset));
376 dso->phnum = eh->e_phnum;
378 /* Reuse the existing mapping for the lowest-address LOAD */
379 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
380 this_min = ph->p_vaddr & -PAGE_SIZE;
381 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
382 off_start = ph->p_offset & -PAGE_SIZE;
383 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
384 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
385 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
386 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
388 if (ph->p_memsz > ph->p_filesz) {
389 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
390 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
391 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
392 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)
396 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
397 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
398 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
402 if (!runtime) reclaim_gaps(base, ph0, eh->e_phentsize, eh->e_phnum);
404 dso->map_len = map_len;
406 dso->dynv = (void *)(base+dyn);
407 if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
410 munmap(map, map_len);
414 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
419 s += strspn(s, ":\n");
420 l = strcspn(s, ":\n");
421 if (l-1 >= INT_MAX) return -1;
422 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
424 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
429 static void decode_dyn(struct dso *p)
431 size_t dyn[DYN_CNT] = {0};
432 decode_vec(p->dynv, dyn, DYN_CNT);
433 p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
434 p->strings = (void *)(p->base + dyn[DT_STRTAB]);
435 if (dyn[0]&(1<<DT_HASH))
436 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
437 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
438 p->ghashtab = (void *)(p->base + *dyn);
441 static struct dso *load_library(const char *name)
443 char buf[2*NAME_MAX+2];
444 const char *pathname;
446 struct dso *p, temp_dso = {0};
452 /* Catch and block attempts to reload the implementation itself */
453 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
454 static const char *rp, reserved[] =
455 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
456 char *z = strchr(name, '.');
459 for (rp=reserved; *rp && memcmp(name+3, rp, l-3); rp+=strlen(rp)+1);
464 tail = ldso->next ? ldso->next : ldso;
470 if (strchr(name, '/')) {
472 fd = open(name, O_RDONLY|O_CLOEXEC);
474 /* Search for the name to see if it's already loaded */
475 for (p=head->next; p; p=p->next) {
476 if (p->shortname && !strcmp(p->shortname, name)) {
481 if (strlen(name) > NAME_MAX) return 0;
483 if (r_path) fd = path_open(name, r_path, buf, sizeof buf);
484 if (fd < 0 && env_path) fd = path_open(name, env_path, buf, sizeof buf);
489 if (ldso->name[0]=='/') {
491 for (s=t=z=ldso->name; *s; s++)
492 if (*s=='/') z=t, t=s;
493 prefix_len = z-ldso->name;
494 if (prefix_len < PATH_MAX)
501 char etc_ldso_path[prefix_len + 1
502 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
503 snprintf(etc_ldso_path, sizeof etc_ldso_path,
504 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
505 (int)prefix_len, prefix);
506 FILE *f = fopen(etc_ldso_path, "rbe");
508 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
515 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
516 fd = path_open(name, sys_path, buf, sizeof buf);
520 if (fd < 0) return 0;
521 if (fstat(fd, &st) < 0) {
525 for (p=head->next; p; p=p->next) {
526 if (p->dev == st.st_dev && p->ino == st.st_ino) {
527 /* If this library was previously loaded with a
528 * pathname but a search found the same inode,
529 * setup its shortname so it can be found by name. */
530 if (!p->shortname && pathname != name)
531 p->shortname = strrchr(p->name, '/')+1;
537 map = noload ? 0 : map_library(fd, &temp_dso);
541 /* Allocate storage for the new DSO. When there is TLS, this
542 * storage must include a reservation for all pre-existing
543 * threads to obtain copies of both the new TLS, and an
544 * extended DTV capable of storing an additional slot for
545 * the newly-loaded DSO. */
546 alloc_size = sizeof *p + strlen(pathname) + 1;
547 if (runtime && temp_dso.tls_image) {
548 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
549 + sizeof(void *) * (tls_cnt+3);
550 n_th = libc.threads_minus_1 + 1;
551 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
552 else alloc_size += n_th * per_th;
554 p = calloc(1, alloc_size);
556 munmap(map, temp_dso.map_len);
559 memcpy(p, &temp_dso, sizeof temp_dso);
565 strcpy(p->name, pathname);
566 /* Add a shortname only if name arg was not an explicit pathname. */
567 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
569 if (runtime && !__pthread_self_init()) {
570 munmap(map, p->map_len);
574 p->tls_id = ++tls_cnt;
575 tls_align = MAXP2(tls_align, p->tls_align);
577 p->tls_offset = tls_offset + ( (tls_align-1) &
578 -(tls_offset + (uintptr_t)p->tls_image) );
579 tls_offset += p->tls_size;
581 tls_offset += p->tls_size + p->tls_align - 1;
582 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
584 p->tls_offset = tls_offset;
586 p->new_dtv = (void *)(-sizeof(size_t) &
587 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
588 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
595 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
600 static void load_deps(struct dso *p)
603 struct dso ***deps = &p->deps, **tmp, *dep;
604 for (; p; p=p->next) {
605 for (i=0; p->dynv[i]; i+=2) {
606 if (p->dynv[i] != DT_RPATH) continue;
607 r_path = (void *)(p->strings + p->dynv[i+1]);
609 for (i=0; p->dynv[i]; i+=2) {
610 if (p->dynv[i] != DT_NEEDED) continue;
611 dep = load_library(p->strings + p->dynv[i+1]);
613 snprintf(errbuf, sizeof errbuf,
614 "Error loading shared library %s: %m (needed by %s)",
615 p->strings + p->dynv[i+1], p->name);
616 if (runtime) longjmp(*rtld_fail, 1);
617 dprintf(2, "%s\n", errbuf);
622 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
623 if (!tmp) longjmp(*rtld_fail, 1);
633 static void load_preload(char *s)
638 for ( ; *s && isspace(*s); s++);
639 for (z=s; *z && !isspace(*z); z++);
647 static void make_global(struct dso *p)
649 for (; p; p=p->next) p->global = 1;
652 static void reloc_all(struct dso *p)
654 size_t dyn[DYN_CNT] = {0};
655 for (; p; p=p->next) {
656 if (p->relocated) continue;
657 decode_vec(p->dynv, dyn, DYN_CNT);
658 #ifdef NEED_ARCH_RELOCS
659 do_arch_relocs(p, head);
661 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
662 2+(dyn[DT_PLTREL]==DT_RELA));
663 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
664 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
669 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
671 for (; cnt--; ph = (void *)((char *)ph + stride))
672 if (ph->p_type == PT_DYNAMIC)
677 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
679 size_t min_addr = -1, max_addr = 0;
680 for (; cnt--; ph = (void *)((char *)ph + stride)) {
681 if (ph->p_type != PT_LOAD) continue;
682 if (ph->p_vaddr < min_addr)
683 min_addr = ph->p_vaddr;
684 if (ph->p_vaddr+ph->p_memsz > max_addr)
685 max_addr = ph->p_vaddr+ph->p_memsz;
687 min_addr &= -PAGE_SIZE;
688 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
689 p->map = p->base + min_addr;
690 p->map_len = max_addr - min_addr;
693 static void do_fini()
696 size_t dyn[DYN_CNT] = {0};
697 for (p=fini_head; p; p=p->fini_next) {
698 if (!p->constructed) continue;
699 decode_vec(p->dynv, dyn, DYN_CNT);
700 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
701 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
702 size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
703 while (n--) ((void (*)(void))*--fn)();
705 #ifndef NO_LEGACY_INITFINI
706 if (dyn[0] & (1<<DT_FINI))
707 ((void (*)(void))(p->base + dyn[DT_FINI]))();
712 static void do_init_fini(struct dso *p)
714 size_t dyn[DYN_CNT] = {0};
715 int need_locking = libc.threads_minus_1;
716 /* Allow recursive calls that arise when a library calls
717 * dlopen from one of its constructors, but block any
718 * other threads until all ctors have finished. */
719 if (need_locking) pthread_mutex_lock(&init_fini_lock);
720 for (; p; p=p->prev) {
721 if (p->constructed) continue;
723 decode_vec(p->dynv, dyn, DYN_CNT);
724 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
725 p->fini_next = fini_head;
728 #ifndef NO_LEGACY_INITFINI
729 if (dyn[0] & (1<<DT_INIT))
730 ((void (*)(void))(p->base + dyn[DT_INIT]))();
732 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
733 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
734 size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
735 while (n--) ((void (*)(void))*fn++)();
737 if (!need_locking && libc.threads_minus_1) {
739 pthread_mutex_lock(&init_fini_lock);
742 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
745 void _dl_debug_state(void)
749 void *__copy_tls(unsigned char *mem)
754 if (!tls_cnt) return mem;
756 void **dtv = (void *)mem;
757 dtv[0] = (void *)tls_cnt;
760 mem += sizeof(void *) * (tls_cnt+1);
761 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
763 mem += sizeof(struct pthread);
765 for (p=head; p; p=p->next) {
766 if (!p->tls_id) continue;
767 dtv[p->tls_id] = mem + p->tls_offset;
768 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
771 mem += libc.tls_size - sizeof(struct pthread);
772 mem -= (uintptr_t)mem & (tls_align-1);
775 for (p=head; p; p=p->next) {
776 if (!p->tls_id) continue;
777 dtv[p->tls_id] = mem - p->tls_offset;
778 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
785 void *__tls_get_addr(size_t *v)
787 pthread_t self = __pthread_self();
788 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
789 return (char *)self->dtv[v[0]]+v[1];
791 /* Block signals to make accessing new TLS async-signal-safe */
793 pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
794 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
795 pthread_sigmask(SIG_SETMASK, &set, 0);
796 return (char *)self->dtv[v[0]]+v[1];
799 /* This is safe without any locks held because, if the caller
800 * is able to request the Nth entry of the DTV, the DSO list
801 * must be valid at least that far out and it was synchronized
802 * at program startup or by an already-completed call to dlopen. */
804 for (p=head; p->tls_id != v[0]; p=p->next);
806 /* Get new DTV space from new DSO if needed */
807 if (v[0] > (size_t)self->dtv[0]) {
808 void **newdtv = p->new_dtv +
809 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
810 memcpy(newdtv, self->dtv,
811 ((size_t)self->dtv[0]+1) * sizeof(void *));
812 newdtv[0] = (void *)v[0];
816 /* Get new TLS memory from new DSO */
817 unsigned char *mem = p->new_tls +
818 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
819 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
820 self->dtv[v[0]] = mem;
821 memcpy(mem, p->tls_image, p->tls_len);
822 pthread_sigmask(SIG_SETMASK, &set, 0);
826 static void update_tls_size()
828 libc.tls_size = ALIGN(
829 (1+tls_cnt) * sizeof(void *) +
831 sizeof(struct pthread) +
836 void *__dynlink(int argc, char **argv)
838 size_t aux[AUX_CNT] = {0};
842 static struct dso builtin_dsos[3];
843 struct dso *const app = builtin_dsos+0;
844 struct dso *const lib = builtin_dsos+1;
845 struct dso *const vdso = builtin_dsos+2;
849 char **envp = argv+argc+1;
851 /* Find aux vector just past environ[] */
852 for (i=argc+1; argv[i]; i++)
853 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
854 env_path = argv[i]+16;
855 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
856 env_preload = argv[i]+11;
857 auxv = (void *)(argv+i+1);
859 decode_vec(auxv, aux, AUX_CNT);
861 /* Only trust user/env if kernel says we're not suid/sgid */
862 if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
863 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
868 /* If the dynamic linker was invoked as a program itself, AT_BASE
869 * will not be set. In that case, we assume the base address is
870 * the start of the page containing the PHDRs; I don't know any
871 * better approach... */
873 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
874 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
877 /* The dynamic linker load address is passed by the kernel
878 * in the AUX vector, so this is easy. */
879 lib->base = (void *)aux[AT_BASE];
880 lib->name = lib->shortname = "libc.so";
882 ehdr = (void *)lib->base;
883 lib->phnum = ehdr->e_phnum;
884 lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
885 find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
886 lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
887 ehdr->e_phnum, ehdr->e_phentsize));
891 size_t interp_off = 0;
892 size_t tls_image = 0;
893 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
894 app->phdr = phdr = (void *)aux[AT_PHDR];
895 app->phnum = aux[AT_PHNUM];
896 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
897 if (phdr->p_type == PT_PHDR)
898 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
899 else if (phdr->p_type == PT_INTERP)
900 interp_off = (size_t)phdr->p_vaddr;
901 else if (phdr->p_type == PT_TLS) {
902 tls_image = phdr->p_vaddr;
903 app->tls_len = phdr->p_filesz;
904 app->tls_size = phdr->p_memsz;
905 app->tls_align = phdr->p_align;
908 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
909 if (interp_off) lib->name = (char *)app->base + interp_off;
911 app->dynv = (void *)(app->base + find_dyn(
912 (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
913 find_map_range((void *)aux[AT_PHDR],
914 aux[AT_PHNUM], aux[AT_PHENT], app);
917 char *ldname = argv[0];
918 size_t l = strlen(ldname);
919 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
920 *argv++ = (void *)-1;
921 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
923 dprintf(2, "musl libc/dynamic program loader\n");
924 dprintf(2, "usage: %s pathname%s\n", ldname,
925 ldd_mode ? "" : " [args]");
928 fd = open(argv[0], O_RDONLY);
930 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
934 ehdr = (void *)map_library(fd, app);
936 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
943 app->phnum = ehdr->e_phnum;
944 app->phdr = (void *)(app->base + ehdr->e_phoff);
945 aux[AT_ENTRY] = ehdr->e_entry;
948 app->tls_id = tls_cnt = 1;
951 tls_offset = app->tls_size
952 + ( -((uintptr_t)app->tls_image + app->tls_size)
953 & (app->tls_align-1) );
955 tls_offset = app->tls_offset = app->tls_size
956 + ( -((uintptr_t)app->tls_image + app->tls_size)
957 & (app->tls_align-1) );
959 tls_align = MAXP2(tls_align, app->tls_align);
964 /* Attach to vdso, if provided by the kernel */
965 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
966 ehdr = (void *)vdso_base;
967 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
968 vdso->phnum = ehdr->e_phnum;
969 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
970 if (phdr->p_type == PT_DYNAMIC)
971 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
972 if (phdr->p_type == PT_LOAD)
973 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
976 vdso->shortname = "linux-gate.so.1";
983 /* Initial dso chain consists only of the app. We temporarily
984 * append the dynamic linker/libc so we can relocate it, then
985 * restore the initial chain in preparation for loading third
986 * party libraries (preload/needed). */
993 /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
995 /* Donate unused parts of app and library mapping to malloc */
996 reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
997 ehdr = (void *)lib->base;
998 reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
999 ehdr->e_phentsize, ehdr->e_phnum);
1001 /* Load preload/needed libraries, add their symbols to the global
1002 * namespace, and perform all remaining relocations. The main
1003 * program must be relocated LAST since it may contain copy
1004 * relocations which depend on libraries' relocations. */
1005 if (env_preload) load_preload(env_preload);
1009 reloc_all(app->next);
1014 void *mem = mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
1015 MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
1016 if (mem==MAP_FAILED ||
1017 !__install_initial_tls(__copy_tls(mem))) {
1018 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1019 argv[0], libc.tls_size);
1024 if (ldso_fail) _exit(127);
1025 if (ldd_mode) _exit(0);
1027 /* Switch to runtime mode: any further failures in the dynamic
1028 * linker are a reportable failure rather than a fatal startup
1029 * error. If the dynamic loader (dlopen) will not be used, free
1030 * all memory used by the dynamic linker. */
1033 #ifndef DYNAMIC_IS_RO
1034 for (i=0; app->dynv[i]; i+=2)
1035 if (app->dynv[i]==DT_DEBUG)
1036 app->dynv[i+1] = (size_t)&debug;
1039 debug.bp = _dl_debug_state;
1041 debug.base = lib->base;
1045 if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1046 __init_libc(envp, argv[0]);
1051 return (void *)aux[AT_ENTRY];
1054 void *dlopen(const char *file, int mode)
1056 struct dso *volatile p, *orig_tail, *next;
1057 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1062 if (!file) return head;
1064 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1065 pthread_rwlock_wrlock(&lock);
1069 orig_tls_cnt = tls_cnt;
1070 orig_tls_offset = tls_offset;
1071 orig_tls_align = tls_align;
1073 noload = mode & RTLD_NOLOAD;
1076 if (setjmp(*rtld_fail)) {
1077 /* Clean up anything new that was (partially) loaded */
1078 if (p && p->deps) for (i=0; p->deps[i]; i++)
1079 if (p->deps[i]->global < 0)
1080 p->deps[i]->global = 0;
1081 for (p=orig_tail->next; p; p=next) {
1083 munmap(p->map, p->map_len);
1087 tls_cnt = orig_tls_cnt;
1088 tls_offset = orig_tls_offset;
1089 tls_align = orig_tls_align;
1095 } else p = load_library(file);
1098 snprintf(errbuf, sizeof errbuf, noload ?
1099 "Library %s is not already loaded" :
1100 "Error loading shared library %s: %m",
1106 /* First load handling */
1109 if (p->deps) for (i=0; p->deps[i]; i++)
1110 if (!p->deps[i]->global)
1111 p->deps[i]->global = -1;
1112 if (!p->global) p->global = -1;
1114 if (p->deps) for (i=0; p->deps[i]; i++)
1115 if (p->deps[i]->global < 0)
1116 p->deps[i]->global = 0;
1117 if (p->global < 0) p->global = 0;
1120 if (mode & RTLD_GLOBAL) {
1121 if (p->deps) for (i=0; p->deps[i]; i++)
1122 p->deps[i]->global = 1;
1128 if (ssp_used) __init_ssp(libc.auxv);
1135 pthread_rwlock_unlock(&lock);
1136 if (p) do_init_fini(orig_tail);
1137 pthread_setcancelstate(cs, 0);
1141 static int invalid_dso_handle(void *h)
1144 for (p=head; p; p=p->next) if (h==p) return 0;
1145 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1150 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1153 uint32_t h = 0, gh = 0;
1155 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1156 if (p == RTLD_DEFAULT) {
1158 } else if (p == RTLD_NEXT) {
1159 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1163 struct symdef def = find_sym(p, s, 0);
1164 if (!def.sym) goto failed;
1165 if ((def.sym->st_info&0xf) == STT_TLS)
1166 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1167 return def.dso->base + def.sym->st_value;
1169 if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1173 sym = gnu_lookup(s, gh, p);
1176 sym = sysv_lookup(s, h, p);
1178 if (sym && (sym->st_info&0xf) == STT_TLS)
1179 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1180 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1181 return p->base + sym->st_value;
1182 if (p->deps) for (i=0; p->deps[i]; i++) {
1183 if (p->deps[i]->ghashtab) {
1184 if (!gh) gh = gnu_hash(s);
1185 sym = gnu_lookup(s, gh, p->deps[i]);
1187 if (!h) h = sysv_hash(s);
1188 sym = sysv_lookup(s, h, p->deps[i]);
1190 if (sym && (sym->st_info&0xf) == STT_TLS)
1191 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1192 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1193 return p->deps[i]->base + sym->st_value;
1197 snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1201 int __dladdr(void *addr, Dl_info *info)
1211 pthread_rwlock_rdlock(&lock);
1212 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1213 pthread_rwlock_unlock(&lock);
1218 strings = p->strings;
1220 nsym = p->hashtab[1];
1224 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1225 sym += p->ghashtab[1];
1226 for (i = 0; i < p->ghashtab[0]; i++) {
1227 if (buckets[i] > nsym)
1231 nsym -= p->ghashtab[1];
1232 hashval = buckets + p->ghashtab[0] + nsym;
1234 while (!(*hashval++ & 1));
1238 for (; nsym; nsym--, sym++) {
1240 && (1<<(sym->st_info&0xf) & OK_TYPES)
1241 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1242 void *symaddr = p->base + sym->st_value;
1243 if (symaddr > addr || symaddr < best)
1246 bestname = strings + sym->st_name;
1247 if (addr == symaddr)
1252 if (!best) return 0;
1254 info->dli_fname = p->name;
1255 info->dli_fbase = p->base;
1256 info->dli_sname = bestname;
1257 info->dli_saddr = best;
1262 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1265 pthread_rwlock_rdlock(&lock);
1266 res = do_dlsym(p, s, ra);
1267 pthread_rwlock_unlock(&lock);
1271 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1273 struct dso *current;
1274 struct dl_phdr_info info;
1276 for(current = head; current;) {
1277 info.dlpi_addr = (uintptr_t)current->base;
1278 info.dlpi_name = current->name;
1279 info.dlpi_phdr = current->phdr;
1280 info.dlpi_phnum = current->phnum;
1281 info.dlpi_adds = gencnt;
1283 info.dlpi_tls_modid = current->tls_id;
1284 info.dlpi_tls_data = current->tls_image;
1286 ret = (callback)(&info, sizeof (info), data);
1288 if (ret != 0) break;
1290 pthread_rwlock_rdlock(&lock);
1291 current = current->next;
1292 pthread_rwlock_unlock(&lock);
1297 static int invalid_dso_handle(void *h)
1299 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1303 void *dlopen(const char *file, int mode)
1307 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1311 int __dladdr (void *addr, Dl_info *info)
1317 int __dlinfo(void *dso, int req, void *res)
1319 if (invalid_dso_handle(dso)) return -1;
1320 if (req != RTLD_DI_LINKMAP) {
1321 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1325 *(struct link_map **)res = dso;
1331 if (!errflag) return 0;
1336 int dlclose(void *p)
1338 return invalid_dso_handle(p);