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);
462 /* Track which names have been resolved
463 * and only report each one once. */
464 static unsigned reported;
465 unsigned mask = 1U<<(rp-reserved);
466 if (!(reported & mask)) {
468 dprintf(1, "\t%s => %s (%p)\n",
476 tail = ldso->next ? ldso->next : ldso;
482 if (strchr(name, '/')) {
484 fd = open(name, O_RDONLY|O_CLOEXEC);
486 /* Search for the name to see if it's already loaded */
487 for (p=head->next; p; p=p->next) {
488 if (p->shortname && !strcmp(p->shortname, name)) {
493 if (strlen(name) > NAME_MAX) return 0;
495 if (r_path) fd = path_open(name, r_path, buf, sizeof buf);
496 if (fd < 0 && env_path) fd = path_open(name, env_path, buf, sizeof buf);
501 if (ldso->name[0]=='/') {
503 for (s=t=z=ldso->name; *s; s++)
504 if (*s=='/') z=t, t=s;
505 prefix_len = z-ldso->name;
506 if (prefix_len < PATH_MAX)
513 char etc_ldso_path[prefix_len + 1
514 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
515 snprintf(etc_ldso_path, sizeof etc_ldso_path,
516 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
517 (int)prefix_len, prefix);
518 FILE *f = fopen(etc_ldso_path, "rbe");
520 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
527 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
528 fd = path_open(name, sys_path, buf, sizeof buf);
532 if (fd < 0) return 0;
533 if (fstat(fd, &st) < 0) {
537 for (p=head->next; p; p=p->next) {
538 if (p->dev == st.st_dev && p->ino == st.st_ino) {
539 /* If this library was previously loaded with a
540 * pathname but a search found the same inode,
541 * setup its shortname so it can be found by name. */
542 if (!p->shortname && pathname != name)
543 p->shortname = strrchr(p->name, '/')+1;
549 map = noload ? 0 : map_library(fd, &temp_dso);
553 /* Allocate storage for the new DSO. When there is TLS, this
554 * storage must include a reservation for all pre-existing
555 * threads to obtain copies of both the new TLS, and an
556 * extended DTV capable of storing an additional slot for
557 * the newly-loaded DSO. */
558 alloc_size = sizeof *p + strlen(pathname) + 1;
559 if (runtime && temp_dso.tls_image) {
560 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
561 + sizeof(void *) * (tls_cnt+3);
562 n_th = libc.threads_minus_1 + 1;
563 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
564 else alloc_size += n_th * per_th;
566 p = calloc(1, alloc_size);
568 munmap(map, temp_dso.map_len);
571 memcpy(p, &temp_dso, sizeof temp_dso);
577 strcpy(p->name, pathname);
578 /* Add a shortname only if name arg was not an explicit pathname. */
579 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
581 if (runtime && !__pthread_self_init()) {
582 munmap(map, p->map_len);
586 p->tls_id = ++tls_cnt;
587 tls_align = MAXP2(tls_align, p->tls_align);
589 p->tls_offset = tls_offset + ( (tls_align-1) &
590 -(tls_offset + (uintptr_t)p->tls_image) );
591 tls_offset += p->tls_size;
593 tls_offset += p->tls_size + p->tls_align - 1;
594 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
596 p->tls_offset = tls_offset;
598 p->new_dtv = (void *)(-sizeof(size_t) &
599 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
600 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
607 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
612 static void load_deps(struct dso *p)
615 struct dso ***deps = &p->deps, **tmp, *dep;
616 for (; p; p=p->next) {
617 for (i=0; p->dynv[i]; i+=2) {
618 if (p->dynv[i] != DT_RPATH) continue;
619 r_path = (void *)(p->strings + p->dynv[i+1]);
621 for (i=0; p->dynv[i]; i+=2) {
622 if (p->dynv[i] != DT_NEEDED) continue;
623 dep = load_library(p->strings + p->dynv[i+1]);
625 snprintf(errbuf, sizeof errbuf,
626 "Error loading shared library %s: %m (needed by %s)",
627 p->strings + p->dynv[i+1], p->name);
628 if (runtime) longjmp(*rtld_fail, 1);
629 dprintf(2, "%s\n", errbuf);
634 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
635 if (!tmp) longjmp(*rtld_fail, 1);
645 static void load_preload(char *s)
650 for ( ; *s && isspace(*s); s++);
651 for (z=s; *z && !isspace(*z); z++);
659 static void make_global(struct dso *p)
661 for (; p; p=p->next) p->global = 1;
664 static void reloc_all(struct dso *p)
666 size_t dyn[DYN_CNT] = {0};
667 for (; p; p=p->next) {
668 if (p->relocated) continue;
669 decode_vec(p->dynv, dyn, DYN_CNT);
670 #ifdef NEED_ARCH_RELOCS
671 do_arch_relocs(p, head);
673 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
674 2+(dyn[DT_PLTREL]==DT_RELA));
675 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
676 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
681 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
683 for (; cnt--; ph = (void *)((char *)ph + stride))
684 if (ph->p_type == PT_DYNAMIC)
689 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
691 size_t min_addr = -1, max_addr = 0;
692 for (; cnt--; ph = (void *)((char *)ph + stride)) {
693 if (ph->p_type != PT_LOAD) continue;
694 if (ph->p_vaddr < min_addr)
695 min_addr = ph->p_vaddr;
696 if (ph->p_vaddr+ph->p_memsz > max_addr)
697 max_addr = ph->p_vaddr+ph->p_memsz;
699 min_addr &= -PAGE_SIZE;
700 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
701 p->map = p->base + min_addr;
702 p->map_len = max_addr - min_addr;
705 static void do_fini()
708 size_t dyn[DYN_CNT] = {0};
709 for (p=fini_head; p; p=p->fini_next) {
710 if (!p->constructed) continue;
711 decode_vec(p->dynv, dyn, DYN_CNT);
712 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
713 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
714 size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
715 while (n--) ((void (*)(void))*--fn)();
717 #ifndef NO_LEGACY_INITFINI
718 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
719 ((void (*)(void))(p->base + dyn[DT_FINI]))();
724 static void do_init_fini(struct dso *p)
726 size_t dyn[DYN_CNT] = {0};
727 int need_locking = libc.threads_minus_1;
728 /* Allow recursive calls that arise when a library calls
729 * dlopen from one of its constructors, but block any
730 * other threads until all ctors have finished. */
731 if (need_locking) pthread_mutex_lock(&init_fini_lock);
732 for (; p; p=p->prev) {
733 if (p->constructed) continue;
735 decode_vec(p->dynv, dyn, DYN_CNT);
736 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
737 p->fini_next = fini_head;
740 #ifndef NO_LEGACY_INITFINI
741 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
742 ((void (*)(void))(p->base + dyn[DT_INIT]))();
744 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
745 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
746 size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
747 while (n--) ((void (*)(void))*fn++)();
749 if (!need_locking && libc.threads_minus_1) {
751 pthread_mutex_lock(&init_fini_lock);
754 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
757 void _dl_debug_state(void)
761 void *__copy_tls(unsigned char *mem)
766 if (!tls_cnt) return mem;
768 void **dtv = (void *)mem;
769 dtv[0] = (void *)tls_cnt;
772 mem += sizeof(void *) * (tls_cnt+1);
773 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
775 mem += sizeof(struct pthread);
777 for (p=head; p; p=p->next) {
778 if (!p->tls_id) continue;
779 dtv[p->tls_id] = mem + p->tls_offset;
780 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
783 mem += libc.tls_size - sizeof(struct pthread);
784 mem -= (uintptr_t)mem & (tls_align-1);
787 for (p=head; p; p=p->next) {
788 if (!p->tls_id) continue;
789 dtv[p->tls_id] = mem - p->tls_offset;
790 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
797 void *__tls_get_addr(size_t *v)
799 pthread_t self = __pthread_self();
800 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
801 return (char *)self->dtv[v[0]]+v[1];
803 /* Block signals to make accessing new TLS async-signal-safe */
805 pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
806 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
807 pthread_sigmask(SIG_SETMASK, &set, 0);
808 return (char *)self->dtv[v[0]]+v[1];
811 /* This is safe without any locks held because, if the caller
812 * is able to request the Nth entry of the DTV, the DSO list
813 * must be valid at least that far out and it was synchronized
814 * at program startup or by an already-completed call to dlopen. */
816 for (p=head; p->tls_id != v[0]; p=p->next);
818 /* Get new DTV space from new DSO if needed */
819 if (v[0] > (size_t)self->dtv[0]) {
820 void **newdtv = p->new_dtv +
821 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
822 memcpy(newdtv, self->dtv,
823 ((size_t)self->dtv[0]+1) * sizeof(void *));
824 newdtv[0] = (void *)v[0];
828 /* Get new TLS memory from new DSO */
829 unsigned char *mem = p->new_tls +
830 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
831 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
832 self->dtv[v[0]] = mem;
833 memcpy(mem, p->tls_image, p->tls_len);
834 pthread_sigmask(SIG_SETMASK, &set, 0);
838 static void update_tls_size()
840 libc.tls_size = ALIGN(
841 (1+tls_cnt) * sizeof(void *) +
843 sizeof(struct pthread) +
848 void *__dynlink(int argc, char **argv)
850 size_t aux[AUX_CNT] = {0};
854 static struct dso builtin_dsos[3];
855 struct dso *const app = builtin_dsos+0;
856 struct dso *const lib = builtin_dsos+1;
857 struct dso *const vdso = builtin_dsos+2;
861 char **envp = argv+argc+1;
863 /* Find aux vector just past environ[] */
864 for (i=argc+1; argv[i]; i++)
865 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
866 env_path = argv[i]+16;
867 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
868 env_preload = argv[i]+11;
869 auxv = (void *)(argv+i+1);
871 decode_vec(auxv, aux, AUX_CNT);
873 /* Only trust user/env if kernel says we're not suid/sgid */
874 if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
875 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
880 /* If the dynamic linker was invoked as a program itself, AT_BASE
881 * will not be set. In that case, we assume the base address is
882 * the start of the page containing the PHDRs; I don't know any
883 * better approach... */
885 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
886 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
889 /* The dynamic linker load address is passed by the kernel
890 * in the AUX vector, so this is easy. */
891 lib->base = (void *)aux[AT_BASE];
892 lib->name = lib->shortname = "libc.so";
894 ehdr = (void *)lib->base;
895 lib->phnum = ehdr->e_phnum;
896 lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
897 find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
898 lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
899 ehdr->e_phnum, ehdr->e_phentsize));
903 size_t interp_off = 0;
904 size_t tls_image = 0;
905 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
906 app->phdr = phdr = (void *)aux[AT_PHDR];
907 app->phnum = aux[AT_PHNUM];
908 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
909 if (phdr->p_type == PT_PHDR)
910 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
911 else if (phdr->p_type == PT_INTERP)
912 interp_off = (size_t)phdr->p_vaddr;
913 else if (phdr->p_type == PT_TLS) {
914 tls_image = phdr->p_vaddr;
915 app->tls_len = phdr->p_filesz;
916 app->tls_size = phdr->p_memsz;
917 app->tls_align = phdr->p_align;
920 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
921 if (interp_off) lib->name = (char *)app->base + interp_off;
923 app->dynv = (void *)(app->base + find_dyn(
924 (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
925 find_map_range((void *)aux[AT_PHDR],
926 aux[AT_PHNUM], aux[AT_PHENT], app);
929 char *ldname = argv[0];
930 size_t l = strlen(ldname);
931 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
932 *argv++ = (void *)-1;
933 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
935 dprintf(2, "musl libc/dynamic program loader\n");
936 dprintf(2, "usage: %s pathname%s\n", ldname,
937 ldd_mode ? "" : " [args]");
940 fd = open(argv[0], O_RDONLY);
942 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
946 ehdr = (void *)map_library(fd, app);
948 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
955 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
956 /* Find the name that would have been used for the dynamic
957 * linker had ldd not taken its place. */
959 for (i=0; i<app->phnum; i++) {
960 if (app->phdr[i].p_type == PT_INTERP)
961 lib->name = (void *)(app->base
962 + app->phdr[i].p_vaddr);
964 dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
968 app->tls_id = tls_cnt = 1;
971 tls_offset = app->tls_size
972 + ( -((uintptr_t)app->tls_image + app->tls_size)
973 & (app->tls_align-1) );
975 tls_offset = app->tls_offset = app->tls_size
976 + ( -((uintptr_t)app->tls_image + app->tls_size)
977 & (app->tls_align-1) );
979 tls_align = MAXP2(tls_align, app->tls_align);
984 /* Attach to vdso, if provided by the kernel */
985 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
986 ehdr = (void *)vdso_base;
987 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
988 vdso->phnum = ehdr->e_phnum;
989 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
990 if (phdr->p_type == PT_DYNAMIC)
991 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
992 if (phdr->p_type == PT_LOAD)
993 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
996 vdso->shortname = "linux-gate.so.1";
1003 /* Initial dso chain consists only of the app. We temporarily
1004 * append the dynamic linker/libc so we can relocate it, then
1005 * restore the initial chain in preparation for loading third
1006 * party libraries (preload/needed). */
1013 /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1015 /* Donate unused parts of app and library mapping to malloc */
1016 reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
1017 ehdr = (void *)lib->base;
1018 reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
1019 ehdr->e_phentsize, ehdr->e_phnum);
1021 /* Load preload/needed libraries, add their symbols to the global
1022 * namespace, and perform all remaining relocations. The main
1023 * program must be relocated LAST since it may contain copy
1024 * relocations which depend on libraries' relocations. */
1025 if (env_preload) load_preload(env_preload);
1029 reloc_all(app->next);
1034 void *mem = mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
1035 MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
1036 if (mem==MAP_FAILED ||
1037 !__install_initial_tls(__copy_tls(mem))) {
1038 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1039 argv[0], libc.tls_size);
1044 if (ldso_fail) _exit(127);
1045 if (ldd_mode) _exit(0);
1047 /* Switch to runtime mode: any further failures in the dynamic
1048 * linker are a reportable failure rather than a fatal startup
1049 * error. If the dynamic loader (dlopen) will not be used, free
1050 * all memory used by the dynamic linker. */
1053 #ifndef DYNAMIC_IS_RO
1054 for (i=0; app->dynv[i]; i+=2)
1055 if (app->dynv[i]==DT_DEBUG)
1056 app->dynv[i+1] = (size_t)&debug;
1059 debug.bp = _dl_debug_state;
1061 debug.base = lib->base;
1065 if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1066 __init_libc(envp, argv[0]);
1071 return (void *)aux[AT_ENTRY];
1074 void *dlopen(const char *file, int mode)
1076 struct dso *volatile p, *orig_tail, *next;
1077 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1082 if (!file) return head;
1084 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1085 pthread_rwlock_wrlock(&lock);
1089 orig_tls_cnt = tls_cnt;
1090 orig_tls_offset = tls_offset;
1091 orig_tls_align = tls_align;
1093 noload = mode & RTLD_NOLOAD;
1096 if (setjmp(*rtld_fail)) {
1097 /* Clean up anything new that was (partially) loaded */
1098 if (p && p->deps) for (i=0; p->deps[i]; i++)
1099 if (p->deps[i]->global < 0)
1100 p->deps[i]->global = 0;
1101 for (p=orig_tail->next; p; p=next) {
1103 munmap(p->map, p->map_len);
1107 tls_cnt = orig_tls_cnt;
1108 tls_offset = orig_tls_offset;
1109 tls_align = orig_tls_align;
1115 } else p = load_library(file);
1118 snprintf(errbuf, sizeof errbuf, noload ?
1119 "Library %s is not already loaded" :
1120 "Error loading shared library %s: %m",
1126 /* First load handling */
1129 if (p->deps) for (i=0; p->deps[i]; i++)
1130 if (!p->deps[i]->global)
1131 p->deps[i]->global = -1;
1132 if (!p->global) p->global = -1;
1134 if (p->deps) for (i=0; p->deps[i]; i++)
1135 if (p->deps[i]->global < 0)
1136 p->deps[i]->global = 0;
1137 if (p->global < 0) p->global = 0;
1140 if (mode & RTLD_GLOBAL) {
1141 if (p->deps) for (i=0; p->deps[i]; i++)
1142 p->deps[i]->global = 1;
1148 if (ssp_used) __init_ssp(libc.auxv);
1155 pthread_rwlock_unlock(&lock);
1156 if (p) do_init_fini(orig_tail);
1157 pthread_setcancelstate(cs, 0);
1161 static int invalid_dso_handle(void *h)
1164 for (p=head; p; p=p->next) if (h==p) return 0;
1165 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1170 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1173 uint32_t h = 0, gh = 0;
1175 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1176 if (p == RTLD_DEFAULT) {
1178 } else if (p == RTLD_NEXT) {
1179 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1183 struct symdef def = find_sym(p, s, 0);
1184 if (!def.sym) goto failed;
1185 if ((def.sym->st_info&0xf) == STT_TLS)
1186 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1187 return def.dso->base + def.sym->st_value;
1189 if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1193 sym = gnu_lookup(s, gh, p);
1196 sym = sysv_lookup(s, h, p);
1198 if (sym && (sym->st_info&0xf) == STT_TLS)
1199 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1200 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1201 return p->base + sym->st_value;
1202 if (p->deps) for (i=0; p->deps[i]; i++) {
1203 if (p->deps[i]->ghashtab) {
1204 if (!gh) gh = gnu_hash(s);
1205 sym = gnu_lookup(s, gh, p->deps[i]);
1207 if (!h) h = sysv_hash(s);
1208 sym = sysv_lookup(s, h, p->deps[i]);
1210 if (sym && (sym->st_info&0xf) == STT_TLS)
1211 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1212 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1213 return p->deps[i]->base + sym->st_value;
1217 snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1221 int __dladdr(void *addr, Dl_info *info)
1231 pthread_rwlock_rdlock(&lock);
1232 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1233 pthread_rwlock_unlock(&lock);
1238 strings = p->strings;
1240 nsym = p->hashtab[1];
1244 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1245 sym += p->ghashtab[1];
1246 for (i = 0; i < p->ghashtab[0]; i++) {
1247 if (buckets[i] > nsym)
1251 nsym -= p->ghashtab[1];
1252 hashval = buckets + p->ghashtab[0] + nsym;
1254 while (!(*hashval++ & 1));
1258 for (; nsym; nsym--, sym++) {
1260 && (1<<(sym->st_info&0xf) & OK_TYPES)
1261 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1262 void *symaddr = p->base + sym->st_value;
1263 if (symaddr > addr || symaddr < best)
1266 bestname = strings + sym->st_name;
1267 if (addr == symaddr)
1272 if (!best) return 0;
1274 info->dli_fname = p->name;
1275 info->dli_fbase = p->base;
1276 info->dli_sname = bestname;
1277 info->dli_saddr = best;
1282 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1285 pthread_rwlock_rdlock(&lock);
1286 res = do_dlsym(p, s, ra);
1287 pthread_rwlock_unlock(&lock);
1291 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1293 struct dso *current;
1294 struct dl_phdr_info info;
1296 for(current = head; current;) {
1297 info.dlpi_addr = (uintptr_t)current->base;
1298 info.dlpi_name = current->name;
1299 info.dlpi_phdr = current->phdr;
1300 info.dlpi_phnum = current->phnum;
1301 info.dlpi_adds = gencnt;
1303 info.dlpi_tls_modid = current->tls_id;
1304 info.dlpi_tls_data = current->tls_image;
1306 ret = (callback)(&info, sizeof (info), data);
1308 if (ret != 0) break;
1310 pthread_rwlock_rdlock(&lock);
1311 current = current->next;
1312 pthread_rwlock_unlock(&lock);
1317 static int invalid_dso_handle(void *h)
1319 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1323 void *dlopen(const char *file, int mode)
1327 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1331 int __dladdr (void *addr, Dl_info *info)
1337 int __dlinfo(void *dso, int req, void *res)
1339 if (invalid_dso_handle(dso)) return -1;
1340 if (req != RTLD_DI_LINKMAP) {
1341 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1345 *(struct link_map **)res = dso;
1351 if (!errflag) return 0;
1356 int dlclose(void *p)
1358 return invalid_dso_handle(p);