20 #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)
55 struct dso *next, *prev;
71 size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
73 unsigned char *new_tls;
74 int new_dtv_idx, new_tls_idx;
86 void __init_ssp(size_t *);
87 void *__install_initial_tls(void *);
89 static struct dso *head, *tail, *libc;
90 static char *env_path, *sys_path, *r_path;
95 static jmp_buf rtld_fail;
96 static pthread_rwlock_t lock;
97 static struct debug debug;
99 static size_t tls_cnt, tls_size;
101 struct debug *_dl_debug_addr = &debug;
106 static void decode_vec(size_t *v, size_t *a, size_t cnt)
108 memset(a, 0, cnt*sizeof(size_t));
109 for (; v[0]; v+=2) if (v[0]<cnt) {
115 static int search_vec(size_t *v, size_t *r, size_t key)
117 for (; v[0]!=key; v+=2)
123 static uint32_t sysv_hash(const char *s0)
125 const unsigned char *s = (void *)s0;
131 return h & 0xfffffff;
134 static uint32_t gnu_hash(const char *s0)
136 const unsigned char *s = (void *)s0;
137 uint_fast32_t h = 5381;
143 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
146 Sym *syms = dso->syms;
147 uint32_t *hashtab = dso->hashtab;
148 char *strings = dso->strings;
149 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
150 if (!strcmp(s, strings+syms[i].st_name))
156 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
160 uint32_t *hashtab = dso->ghashtab;
161 uint32_t nbuckets = hashtab[0];
162 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
165 uint32_t n = buckets[h1 % nbuckets];
169 strings = dso->strings;
171 hashval = buckets + nbuckets + (n - hashtab[1]);
173 for (h1 |= 1; ; sym++) {
175 if ((h1 == (h2|1)) && !strcmp(s, strings + sym->st_name))
183 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
184 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK)
186 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
188 uint32_t h = 0, gh = 0;
189 struct symdef def = {0};
192 if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
195 if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
197 for (; dso; dso=dso->next) {
199 if (!dso->global) continue;
201 if (!gh) gh = gnu_hash(s);
202 sym = gnu_lookup(s, gh, dso);
204 if (!h) h = sysv_hash(s);
205 sym = sysv_lookup(s, h, dso);
207 if (sym && (!need_def || sym->st_shndx) && sym->st_value
208 && (1<<(sym->st_info&0xf) & OK_TYPES)
209 && (1<<(sym->st_info>>4) & OK_BINDS)) {
210 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
213 if (sym->st_info>>4 == STB_GLOBAL) break;
219 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
221 unsigned char *base = dso->base;
222 Sym *syms = dso->syms;
223 char *strings = dso->strings;
231 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
232 type = R_TYPE(rel[1]);
233 sym_index = R_SYM(rel[1]);
235 sym = syms + sym_index;
236 name = strings + sym->st_name;
237 ctx = IS_COPY(type) ? head->next : head;
238 def = find_sym(ctx, name, IS_PLT(type));
239 if (!def.sym && sym->st_info>>4 != STB_WEAK) {
240 snprintf(errbuf, sizeof errbuf,
241 "Error relocating %s: %s: symbol not found",
243 if (runtime) longjmp(rtld_fail, 1);
244 dprintf(2, "%s\n", errbuf);
253 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
254 stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
255 def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
259 /* A huge hack: to make up for the wastefulness of shared libraries
260 * needing at least a page of dirty memory even if they have no global
261 * data, we reclaim the gaps at the beginning and end of writable maps
262 * and "donate" them to the heap by setting up minimal malloc
263 * structures and then freeing them. */
265 static void reclaim(unsigned char *base, size_t start, size_t end)
268 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
269 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
270 if (start>end || end-start < 4*sizeof(size_t)) return;
271 a = (size_t *)(base + start);
272 z = (size_t *)(base + end);
274 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
279 static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
281 for (; phcnt--; ph=(void *)((char *)ph+phent)) {
282 if (ph->p_type!=PT_LOAD) continue;
283 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
284 reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
285 reclaim(base, ph->p_vaddr+ph->p_memsz,
286 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
290 static void *map_library(int fd, struct dso *dso)
292 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
294 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
295 size_t this_min, this_max;
300 unsigned char *map, *base;
305 ssize_t l = read(fd, buf, sizeof buf);
306 if (l<sizeof *eh) return 0;
308 phsize = eh->e_phentsize * eh->e_phnum;
309 if (phsize + sizeof *eh > l) return 0;
310 if (eh->e_phoff + phsize > l) {
311 l = pread(fd, buf+1, phsize, eh->e_phoff);
312 if (l != phsize) return 0;
313 eh->e_phoff = sizeof *eh;
315 ph = (void *)((char *)buf + eh->e_phoff);
316 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
317 if (ph->p_type == PT_DYNAMIC)
319 if (ph->p_type == PT_TLS) {
320 tls_image = ph->p_vaddr;
321 dso->tls_align = ph->p_align;
322 dso->tls_len = ph->p_filesz;
323 dso->tls_size = ph->p_memsz;
325 if (ph->p_type != PT_LOAD) continue;
326 if (ph->p_vaddr < addr_min) {
327 addr_min = ph->p_vaddr;
328 off_start = ph->p_offset;
329 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
330 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
331 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
333 if (ph->p_vaddr+ph->p_memsz > addr_max) {
334 addr_max = ph->p_vaddr+ph->p_memsz;
338 addr_max += PAGE_SIZE-1;
339 addr_max &= -PAGE_SIZE;
340 addr_min &= -PAGE_SIZE;
341 off_start &= -PAGE_SIZE;
342 map_len = addr_max - addr_min + off_start;
343 /* The first time, we map too much, possibly even more than
344 * the length of the file. This is okay because we will not
345 * use the invalid part; we just need to reserve the right
346 * amount of virtual address space to map over later. */
347 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
348 if (map==MAP_FAILED) return 0;
349 base = map - addr_min;
350 ph = (void *)((char *)buf + eh->e_phoff);
351 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
352 if (ph->p_type != PT_LOAD) continue;
353 /* Reuse the existing mapping for the lowest-address LOAD */
354 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
355 this_min = ph->p_vaddr & -PAGE_SIZE;
356 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
357 off_start = ph->p_offset & -PAGE_SIZE;
358 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
359 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
360 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
361 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
363 if (ph->p_memsz > ph->p_filesz) {
364 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
365 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
366 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
367 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)
371 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
372 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
373 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
377 if (!runtime) reclaim_gaps(base, (void *)((char *)buf + eh->e_phoff),
378 eh->e_phentsize, eh->e_phnum);
380 dso->map_len = map_len;
382 dso->dynv = (void *)(base+dyn);
383 if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
386 munmap(map, map_len);
390 static int path_open(const char *name, const char *search, char *buf, size_t buf_size)
392 const char *s=search, *z;
398 l = z ? z-s : strlen(s);
399 snprintf(buf, buf_size, "%.*s/%s", l, s, name);
400 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
405 static void decode_dyn(struct dso *p)
407 size_t dyn[DYN_CNT] = {0};
408 decode_vec(p->dynv, dyn, DYN_CNT);
409 p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
410 p->strings = (void *)(p->base + dyn[DT_STRTAB]);
411 if (dyn[0]&(1<<DT_HASH))
412 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
413 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
414 p->ghashtab = (void *)(p->base + *dyn);
417 static struct dso *load_library(const char *name)
419 char buf[2*NAME_MAX+2];
420 const char *pathname;
421 unsigned char *base, *map;
422 size_t dyno, map_len;
423 struct dso *p, temp_dso = {0};
429 /* Catch and block attempts to reload the implementation itself */
430 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
431 static const char *rp, reserved[] =
432 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
433 char *z = strchr(name, '.');
436 for (rp=reserved; *rp && memcmp(name+3, rp, l-3); rp+=strlen(rp)+1);
441 tail = libc->next ? libc->next : libc;
447 if (strchr(name, '/')) {
449 fd = open(name, O_RDONLY|O_CLOEXEC);
451 /* Search for the name to see if it's already loaded */
452 for (p=head->next; p; p=p->next) {
453 if (p->shortname && !strcmp(p->shortname, name)) {
458 if (strlen(name) > NAME_MAX) return 0;
460 if (r_path) fd = path_open(name, r_path, buf, sizeof buf);
461 if (fd < 0 && env_path) fd = path_open(name, env_path, buf, sizeof buf);
464 FILE *f = fopen(ETC_LDSO_PATH, "rbe");
466 if (getline(&sys_path, (size_t[1]){0}, f) > 0)
467 sys_path[strlen(sys_path)-1]=0;
471 if (sys_path) fd = path_open(name, sys_path, buf, sizeof buf);
472 else fd = path_open(name, "/lib:/usr/local/lib:/usr/lib", buf, sizeof buf);
476 if (fd < 0) return 0;
477 if (fstat(fd, &st) < 0) {
481 for (p=head->next; p; p=p->next) {
482 if (p->dev == st.st_dev && p->ino == st.st_ino) {
483 /* If this library was previously loaded with a
484 * pathname but a search found the same inode,
485 * setup its shortname so it can be found by name. */
486 if (!p->shortname && pathname != name)
487 p->shortname = strrchr(p->name, '/')+1;
493 map = map_library(fd, &temp_dso);
497 /* Allocate storage for the new DSO. When there is TLS, this
498 * storage must include a reservation for all pre-existing
499 * threads to obtain copies of both the new TLS, and an
500 * extended DTV capable of storing an additional slot for
501 * the newly-loaded DSO. */
502 alloc_size = sizeof *p + strlen(pathname) + 1;
503 if (runtime && temp_dso.tls_image) {
504 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
505 + sizeof(void *) * (tls_cnt+3);
506 n_th = __libc.threads_minus_1 + 1;
507 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
508 else alloc_size += n_th * per_th;
510 p = calloc(1, alloc_size);
512 munmap(map, map_len);
515 memcpy(p, &temp_dso, sizeof temp_dso);
521 strcpy(p->name, pathname);
522 /* Add a shortname only if name arg was not an explicit pathname. */
523 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
525 p->tls_id = ++tls_cnt;
526 tls_size += p->tls_size + p->tls_align + 8*sizeof(size_t) - 1
528 p->new_dtv = (void *)(-sizeof(size_t) &
529 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
530 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
537 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, base);
542 static void load_deps(struct dso *p)
545 struct dso ***deps = &p->deps, **tmp, *dep;
546 for (; p; p=p->next) {
547 for (i=0; p->dynv[i]; i+=2) {
548 if (p->dynv[i] != DT_RPATH) continue;
549 r_path = (void *)(p->strings + p->dynv[i+1]);
551 for (i=0; p->dynv[i]; i+=2) {
552 if (p->dynv[i] != DT_NEEDED) continue;
553 dep = load_library(p->strings + p->dynv[i+1]);
555 snprintf(errbuf, sizeof errbuf,
556 "Error loading shared library %s: %m (needed by %s)",
557 p->strings + p->dynv[i+1], p->name);
558 if (runtime) longjmp(rtld_fail, 1);
559 dprintf(2, "%s\n", errbuf);
564 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
565 if (!tmp) longjmp(rtld_fail, 1);
575 static void load_preload(char *s)
580 for ( ; *s && isspace(*s); s++);
581 for (z=s; *z && !isspace(*z); z++);
589 static void make_global(struct dso *p)
591 for (; p; p=p->next) p->global = 1;
594 static void reloc_all(struct dso *p)
596 size_t dyn[DYN_CNT] = {0};
597 for (; p; p=p->next) {
598 if (p->relocated) continue;
599 decode_vec(p->dynv, dyn, DYN_CNT);
600 #ifdef NEED_ARCH_RELOCS
601 do_arch_relocs(p, head);
603 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
604 2+(dyn[DT_PLTREL]==DT_RELA));
605 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
606 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
611 static void free_all(struct dso *p)
616 if (p->map && p!=libc && p!=head) free(p);
621 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
623 for (; cnt--; ph = (void *)((char *)ph + stride))
624 if (ph->p_type == PT_DYNAMIC)
629 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
631 size_t min_addr = -1, max_addr = 0;
632 for (; cnt--; ph = (void *)((char *)ph + stride)) {
633 if (ph->p_type != PT_LOAD) continue;
634 if (ph->p_vaddr < min_addr)
635 min_addr = ph->p_vaddr;
636 if (ph->p_vaddr+ph->p_memsz > max_addr)
637 max_addr = ph->p_vaddr+ph->p_memsz;
639 min_addr &= -PAGE_SIZE;
640 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
641 p->map = p->base + min_addr;
642 p->map_len = max_addr - min_addr;
645 static void do_init_fini(struct dso *p)
647 size_t dyn[DYN_CNT] = {0};
648 for (; p; p=p->prev) {
649 if (p->constructed) return;
650 decode_vec(p->dynv, dyn, DYN_CNT);
651 if (dyn[0] & (1<<DT_FINI))
652 atexit((void (*)(void))(p->base + dyn[DT_FINI]));
653 if (dyn[0] & (1<<DT_INIT))
654 ((void (*)(void))(p->base + dyn[DT_INIT]))();
659 void _dl_debug_state(void)
663 void *__copy_tls(unsigned char *mem)
666 void **dtv = (void *)mem;
667 dtv[0] = (void *)tls_cnt;
668 mem = (void *)(dtv + tls_cnt + 1);
669 for (p=tail; p; p=p->prev) {
670 if (!p->tls_id) continue;
671 mem += -p->tls_len & (4*sizeof(size_t)-1);
672 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
674 dtv[p->tls_id] = mem;
675 memcpy(mem, p->tls_image, p->tls_len);
678 ((pthread_t)mem)->dtv = dtv;
682 void *__tls_get_addr(size_t *v)
684 pthread_t self = __pthread_self();
685 if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
686 return (char *)self->dtv[v[0]]+v[1];
688 /* Block signals to make accessing new TLS async-signal-safe */
691 pthread_sigmask(SIG_BLOCK, &set, &set);
692 if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
693 pthread_sigmask(SIG_SETMASK, &set, 0);
694 return (char *)self->dtv[v[0]]+v[1];
697 /* This is safe without any locks held because, if the caller
698 * is able to request the Nth entry of the DTV, the DSO list
699 * must be valid at least that far out and it was synchronized
700 * at program startup or by an already-completed call to dlopen. */
702 for (p=head; p->tls_id != v[0]; p=p->next);
704 /* Get new DTV space from new DSO if needed */
705 if (!self->dtv || v[0] > (size_t)self->dtv[0]) {
706 void **newdtv = p->new_dtv +
707 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
708 if (self->dtv) memcpy(newdtv, self->dtv,
709 ((size_t)self->dtv[0]+1) * sizeof(void *));
710 newdtv[0] = (void *)v[0];
714 /* Get new TLS memory from new DSO */
715 unsigned char *mem = p->new_tls +
716 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
717 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
718 self->dtv[v[0]] = mem;
719 memcpy(mem, p->tls_image, p->tls_size);
720 pthread_sigmask(SIG_SETMASK, &set, 0);
724 void *__dynlink(int argc, char **argv)
726 size_t aux[AUX_CNT] = {0};
730 static struct dso builtin_dsos[3];
731 struct dso *const app = builtin_dsos+0;
732 struct dso *const lib = builtin_dsos+1;
733 struct dso *const vdso = builtin_dsos+2;
737 /* Find aux vector just past environ[] */
738 for (i=argc+1; argv[i]; i++)
739 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
740 env_path = argv[i]+16;
741 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
742 env_preload = argv[i]+11;
743 auxv = (void *)(argv+i+1);
745 decode_vec(auxv, aux, AUX_CNT);
747 /* Only trust user/env if kernel says we're not suid/sgid */
748 if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
749 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
754 /* If the dynamic linker was invoked as a program itself, AT_BASE
755 * will not be set. In that case, we assume the base address is
756 * the start of the page containing the PHDRs; I don't know any
757 * better approach... */
759 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
760 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
763 /* The dynamic linker load address is passed by the kernel
764 * in the AUX vector, so this is easy. */
765 lib->base = (void *)aux[AT_BASE];
766 lib->name = lib->shortname = "libc.so";
768 ehdr = (void *)lib->base;
769 find_map_range((void *)(aux[AT_BASE]+ehdr->e_phoff),
770 ehdr->e_phnum, ehdr->e_phentsize, lib);
771 lib->dynv = (void *)(lib->base + find_dyn(
772 (void *)(aux[AT_BASE]+ehdr->e_phoff),
773 ehdr->e_phnum, ehdr->e_phentsize));
777 size_t interp_off = 0;
778 size_t tls_image = 0;
779 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
780 phdr = (void *)aux[AT_PHDR];
781 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
782 if (phdr->p_type == PT_PHDR)
783 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
784 else if (phdr->p_type == PT_INTERP)
785 interp_off = (size_t)phdr->p_vaddr;
786 else if (phdr->p_type == PT_TLS) {
787 tls_image = phdr->p_vaddr;
788 app->tls_len = phdr->p_filesz;
789 app->tls_size = phdr->p_memsz;
790 app->tls_align = phdr->p_align;
793 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
794 if (interp_off) lib->name = (char *)app->base + interp_off;
796 app->dynv = (void *)(app->base + find_dyn(
797 (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
798 find_map_range((void *)aux[AT_PHDR],
799 aux[AT_PHNUM], aux[AT_PHENT], app);
802 char *ldname = argv[0];
803 size_t dyno, l = strlen(ldname);
804 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
805 *argv++ = (void *)-1;
806 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
808 dprintf(2, "musl libc/dynamic program loader\n");
809 dprintf(2, "usage: %s pathname%s\n", ldname,
810 ldd_mode ? "" : " [args]");
813 fd = open(argv[0], O_RDONLY);
815 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
819 ehdr = (void *)map_library(fd, app);
821 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
828 aux[AT_ENTRY] = ehdr->e_entry;
831 app->tls_id = ++tls_cnt;
832 tls_size += app->tls_size+app->tls_align + 8*sizeof(size_t)-1
836 app->constructed = 1;
839 /* Attach to vdso, if provided by the kernel */
840 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
841 ehdr = (void *)vdso_base;
842 phdr = (void *)(vdso_base + ehdr->e_phoff);
843 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
844 if (phdr->p_type == PT_DYNAMIC)
845 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
846 if (phdr->p_type == PT_LOAD)
847 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
849 vdso->name = vdso->shortname = "linux-gate.so.1";
856 /* Initial dso chain consists only of the app. We temporarily
857 * append the dynamic linker/libc so we can relocate it, then
858 * restore the initial chain in preparation for loading third
859 * party libraries (preload/needed). */
866 /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
868 /* Donate unused parts of app and library mapping to malloc */
869 reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
870 ehdr = (void *)lib->base;
871 reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
872 ehdr->e_phentsize, ehdr->e_phnum);
874 /* Load preload/needed libraries, add their symbols to the global
875 * namespace, and perform all remaining relocations. The main
876 * program must be relocated LAST since it may contain copy
877 * relocations which depend on libraries' relocations. */
878 if (env_preload) load_preload(env_preload);
882 /* Make an initial pass setting up TLS before performing relocs.
883 * This provides the TP-based offset of each DSO's TLS for
884 * use in TP-relative relocations. After relocations, we need
885 * to copy the TLS images again in case they had relocs. */
886 tls_size += sizeof(struct pthread) + 4*sizeof(size_t);
887 __libc.tls_size = tls_size;
890 void *mem = mmap(0, __libc.tls_size, PROT_READ|PROT_WRITE,
891 MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
892 if (mem==MAP_FAILED ||
893 !__install_initial_tls(__copy_tls(mem))) {
894 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
898 for (p=head; p; p=p->next) {
899 if (!p->tls_id) continue;
900 p->tls_offset = (char *)__pthread_self()
901 - (char *)__pthread_self()->dtv[p->tls_id];
905 reloc_all(app->next);
908 /* The initial DTV is located at the base of the memory
909 * allocated for TLS. Repeat copying TLS to pick up relocs. */
910 if (tls_cnt) __copy_tls((void *)__pthread_self()->dtv);
912 if (ldso_fail) _exit(127);
913 if (ldd_mode) _exit(0);
915 /* Switch to runtime mode: any further failures in the dynamic
916 * linker are a reportable failure rather than a fatal startup
917 * error. If the dynamic loader (dlopen) will not be used, free
918 * all memory used by the dynamic linker. */
921 #ifndef DYNAMIC_IS_RO
922 for (i=0; app->dynv[i]; i+=2)
923 if (app->dynv[i]==DT_DEBUG)
924 app->dynv[i+1] = (size_t)&debug;
927 debug.bp = _dl_debug_state;
929 debug.base = lib->base;
933 if (ssp_used) __init_ssp(auxv);
938 return (void *)aux[AT_ENTRY];
941 void *dlopen(const char *file, int mode)
943 struct dso *volatile p, *orig_tail, *next;
948 if (!file) return head;
950 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
951 pthread_rwlock_wrlock(&lock);
955 orig_tls_cnt = tls_cnt;
958 if (setjmp(rtld_fail)) {
959 /* Clean up anything new that was (partially) loaded */
960 if (p && p->deps) for (i=0; p->deps[i]; i++)
961 if (p->deps[i]->global < 0)
962 p->deps[i]->global = 0;
963 for (p=orig_tail->next; p; p=next) {
965 munmap(p->map, p->map_len);
969 tls_cnt = orig_tls_cnt;
970 tls_size = __libc.tls_size;
976 } else p = load_library(file);
979 snprintf(errbuf, sizeof errbuf,
980 "Error loading shared library %s: %m", file);
985 /* First load handling */
988 if (p->deps) for (i=0; p->deps[i]; i++)
989 if (!p->deps[i]->global)
990 p->deps[i]->global = -1;
991 if (!p->global) p->global = -1;
993 if (p->deps) for (i=0; p->deps[i]; i++)
994 if (p->deps[i]->global < 0)
995 p->deps[i]->global = 0;
996 if (p->global < 0) p->global = 0;
999 if (mode & RTLD_GLOBAL) {
1000 if (p->deps) for (i=0; p->deps[i]; i++)
1001 p->deps[i]->global = 1;
1005 __libc.tls_size = tls_size;
1007 if (ssp_used) __init_ssp(auxv);
1014 pthread_rwlock_unlock(&lock);
1015 pthread_setcancelstate(cs, 0);
1019 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1022 uint32_t h = 0, gh = 0;
1024 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1025 if (p == RTLD_NEXT) {
1026 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1029 struct symdef def = find_sym(p->next, s, 0);
1030 if (!def.sym) goto failed;
1031 return def.dso->base + def.sym->st_value;
1035 sym = gnu_lookup(s, gh, p);
1038 sym = sysv_lookup(s, h, p);
1040 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1041 return p->base + sym->st_value;
1042 if (p->deps) for (i=0; p->deps[i]; i++) {
1043 if (p->deps[i]->ghashtab) {
1044 if (!gh) gh = gnu_hash(s);
1045 sym = gnu_lookup(s, gh, p->deps[i]);
1047 if (!h) h = sysv_hash(s);
1048 sym = sysv_lookup(s, h, p->deps[i]);
1050 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1051 return p->deps[i]->base + sym->st_value;
1055 snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1059 int __dladdr(void *addr, Dl_info *info)
1069 pthread_rwlock_rdlock(&lock);
1070 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1071 pthread_rwlock_unlock(&lock);
1076 strings = p->strings;
1078 nsym = p->hashtab[1];
1082 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1083 sym += p->ghashtab[1];
1084 for (i = 0; i < p->ghashtab[0]; i++) {
1085 if (buckets[i] > nsym)
1089 nsym -= p->ghashtab[1];
1090 hashval = buckets + p->ghashtab[0] + nsym;
1092 while (!(*hashval++ & 1));
1096 for (; nsym; nsym--, sym++) {
1097 if (sym->st_shndx && sym->st_value
1098 && (1<<(sym->st_info&0xf) & OK_TYPES)
1099 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1100 void *symaddr = p->base + sym->st_value;
1101 if (symaddr > addr || symaddr < best)
1104 bestname = strings + sym->st_name;
1105 if (addr == symaddr)
1110 if (!best) return 0;
1112 info->dli_fname = p->name;
1113 info->dli_fbase = p->base;
1114 info->dli_sname = bestname;
1115 info->dli_saddr = best;
1120 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1123 pthread_rwlock_rdlock(&lock);
1124 res = do_dlsym(p, s, ra);
1125 pthread_rwlock_unlock(&lock);
1129 void *dlopen(const char *file, int mode)
1133 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1137 int __dladdr (void *addr, Dl_info *info)
1145 if (!errflag) return 0;
1150 int dlclose(void *p)