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 struct dso **deps, *needed_by;
77 char *rpath_orig, *rpath;
79 size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
81 unsigned char *new_tls;
82 int new_dtv_idx, new_tls_idx;
83 struct dso *fini_next;
95 void __init_ssp(size_t *);
96 void *__install_initial_tls(void *);
97 void __init_libc(char **, char *);
99 static struct dso *head, *tail, *ldso, *fini_head;
100 static char *env_path, *sys_path;
101 static unsigned long long gencnt;
105 static int ldso_fail;
107 static jmp_buf *rtld_fail;
108 static pthread_rwlock_t lock;
109 static struct debug debug;
110 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
111 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
113 struct debug *_dl_debug_addr = &debug;
118 static void decode_vec(size_t *v, size_t *a, size_t cnt)
120 memset(a, 0, cnt*sizeof(size_t));
121 for (; v[0]; v+=2) if (v[0]<cnt) {
127 static int search_vec(size_t *v, size_t *r, size_t key)
129 for (; v[0]!=key; v+=2)
135 static uint32_t sysv_hash(const char *s0)
137 const unsigned char *s = (void *)s0;
143 return h & 0xfffffff;
146 static uint32_t gnu_hash(const char *s0)
148 const unsigned char *s = (void *)s0;
149 uint_fast32_t h = 5381;
155 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
158 Sym *syms = dso->syms;
159 uint32_t *hashtab = dso->hashtab;
160 char *strings = dso->strings;
161 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
162 if ((!dso->versym || dso->versym[i] >= 0)
163 && (!strcmp(s, strings+syms[i].st_name)))
169 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
171 Sym *syms = dso->syms;
172 char *strings = dso->strings;
173 uint32_t *hashtab = dso->ghashtab;
174 uint32_t nbuckets = hashtab[0];
175 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
178 uint32_t i = buckets[h1 % nbuckets];
182 hashval = buckets + nbuckets + (i - hashtab[1]);
184 for (h1 |= 1; ; i++) {
186 if ((!dso->versym || dso->versym[i] >= 0)
187 && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
195 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
196 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
198 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
200 uint32_t h = 0, gh = 0;
201 struct symdef def = {0};
204 if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
207 if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
209 for (; dso; dso=dso->next) {
211 if (!dso->global) continue;
213 if (!gh) gh = gnu_hash(s);
214 sym = gnu_lookup(s, gh, dso);
216 if (!h) h = sysv_hash(s);
217 sym = sysv_lookup(s, h, dso);
221 if (need_def || (sym->st_info&0xf) == STT_TLS)
224 if ((sym->st_info&0xf) != STT_TLS)
226 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
227 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
229 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
232 if (sym->st_info>>4 == STB_GLOBAL) break;
237 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
239 unsigned char *base = dso->base;
240 Sym *syms = dso->syms;
241 char *strings = dso->strings;
249 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
250 type = R_TYPE(rel[1]);
251 sym_index = R_SYM(rel[1]);
253 sym = syms + sym_index;
254 name = strings + sym->st_name;
255 ctx = IS_COPY(type) ? head->next : head;
256 def = find_sym(ctx, name, IS_PLT(type));
257 if (!def.sym && sym->st_info>>4 != STB_WEAK) {
258 snprintf(errbuf, sizeof errbuf,
259 "Error relocating %s: %s: symbol not found",
261 if (runtime) longjmp(*rtld_fail, 1);
262 dprintf(2, "%s\n", errbuf);
271 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
272 stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
273 def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
277 /* A huge hack: to make up for the wastefulness of shared libraries
278 * needing at least a page of dirty memory even if they have no global
279 * data, we reclaim the gaps at the beginning and end of writable maps
280 * and "donate" them to the heap by setting up minimal malloc
281 * structures and then freeing them. */
283 static void reclaim(unsigned char *base, size_t start, size_t end)
286 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
287 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
288 if (start>end || end-start < 4*sizeof(size_t)) return;
289 a = (size_t *)(base + start);
290 z = (size_t *)(base + end);
292 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
297 static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
299 for (; phcnt--; ph=(void *)((char *)ph+phent)) {
300 if (ph->p_type!=PT_LOAD) continue;
301 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
302 reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
303 reclaim(base, ph->p_vaddr+ph->p_memsz,
304 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
308 static void *map_library(int fd, struct dso *dso)
310 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
311 void *allocated_buf=0;
313 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
314 size_t this_min, this_max;
319 unsigned char *map=MAP_FAILED, *base;
324 ssize_t l = read(fd, buf, sizeof buf);
327 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
329 phsize = eh->e_phentsize * eh->e_phnum;
330 if (phsize > sizeof buf - sizeof *eh) {
331 allocated_buf = malloc(phsize);
332 if (!allocated_buf) return 0;
333 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
334 if (l < 0) goto error;
335 if (l != phsize) goto noexec;
336 ph = ph0 = allocated_buf;
337 } else if (eh->e_phoff + phsize > l) {
338 l = pread(fd, buf+1, phsize, eh->e_phoff);
339 if (l < 0) goto error;
340 if (l != phsize) goto noexec;
341 ph = ph0 = (void *)(buf + 1);
343 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
345 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
346 if (ph->p_type == PT_DYNAMIC)
348 if (ph->p_type == PT_TLS) {
349 tls_image = ph->p_vaddr;
350 dso->tls_align = ph->p_align;
351 dso->tls_len = ph->p_filesz;
352 dso->tls_size = ph->p_memsz;
354 if (ph->p_type != PT_LOAD) continue;
355 if (ph->p_vaddr < addr_min) {
356 addr_min = ph->p_vaddr;
357 off_start = ph->p_offset;
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));
362 if (ph->p_vaddr+ph->p_memsz > addr_max) {
363 addr_max = ph->p_vaddr+ph->p_memsz;
366 if (!dyn) goto noexec;
367 addr_max += PAGE_SIZE-1;
368 addr_max &= -PAGE_SIZE;
369 addr_min &= -PAGE_SIZE;
370 off_start &= -PAGE_SIZE;
371 map_len = addr_max - addr_min + off_start;
372 /* The first time, we map too much, possibly even more than
373 * the length of the file. This is okay because we will not
374 * use the invalid part; we just need to reserve the right
375 * amount of virtual address space to map over later. */
376 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
377 if (map==MAP_FAILED) goto error;
378 /* If the loaded file is not relocatable and the requested address is
379 * not available, then the load operation must fail. */
380 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
384 base = map - addr_min;
387 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
388 if (ph->p_type != PT_LOAD) continue;
389 /* Check if the programs headers are in this load segment, and
390 * if so, record the address for use by dl_iterate_phdr. */
391 if (!dso->phdr && eh->e_phoff >= ph->p_offset
392 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
393 dso->phdr = (void *)(base + ph->p_vaddr
394 + (eh->e_phoff-ph->p_offset));
395 dso->phnum = eh->e_phnum;
397 /* Reuse the existing mapping for the lowest-address LOAD */
398 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
399 this_min = ph->p_vaddr & -PAGE_SIZE;
400 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
401 off_start = ph->p_offset & -PAGE_SIZE;
402 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
403 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
404 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
405 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
407 if (ph->p_memsz > ph->p_filesz) {
408 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
409 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
410 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
411 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)
415 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
416 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
417 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
421 if (!runtime) reclaim_gaps(base, ph0, eh->e_phentsize, eh->e_phnum);
423 dso->map_len = map_len;
425 dso->dynv = (void *)(base+dyn);
426 if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
432 if (map!=MAP_FAILED) munmap(map, map_len);
437 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
442 s += strspn(s, ":\n");
443 l = strcspn(s, ":\n");
444 if (l-1 >= INT_MAX) return -1;
445 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
447 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
452 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
455 const char *s, *t, *origin;
457 if (p->rpath) return 0;
458 if (!p->rpath_orig) return -1;
459 if (!strchr(p->rpath_orig, '$')) {
460 p->rpath = p->rpath_orig;
465 while ((t=strstr(s, "$ORIGIN")) || (t=strstr(s, "${ORIGIN}"))) {
469 if (n > SSIZE_MAX/PATH_MAX) return -1;
471 if (p->kernel_mapped) {
472 /* $ORIGIN searches cannot be performed for the main program
473 * when it is suid/sgid/AT_SECURE. This is because the
474 * pathname is under the control of the caller of execve.
475 * For libraries, however, $ORIGIN can be processed safely
476 * since the library's pathname came from a trusted source
477 * (either system paths or a call to dlopen). */
480 if (readlink("/proc/self/exe", buf, buf_size) >= buf_size)
486 t = strrchr(origin, '/');
487 l = t ? t-origin : 0;
488 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
489 if (!p->rpath) return -1;
493 while ((t=strstr(s, "$ORIGIN")) || (t=strstr(s, "${ORIGIN}"))) {
496 memcpy(d, origin, l);
498 s = t + 7 + 2*(t[1]=='{');
504 static void decode_dyn(struct dso *p)
506 size_t dyn[DYN_CNT] = {0};
507 decode_vec(p->dynv, dyn, DYN_CNT);
508 p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
509 p->strings = (void *)(p->base + dyn[DT_STRTAB]);
510 if (dyn[0]&(1<<DT_HASH))
511 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
512 if (dyn[0]&(1<<DT_RPATH))
513 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
514 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
515 p->ghashtab = (void *)(p->base + *dyn);
516 if (search_vec(p->dynv, dyn, DT_VERSYM))
517 p->versym = (void *)(p->base + *dyn);
520 static struct dso *load_library(const char *name, struct dso *needed_by)
522 char buf[2*NAME_MAX+2];
523 const char *pathname;
525 struct dso *p, temp_dso = {0};
532 /* Catch and block attempts to reload the implementation itself */
533 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
534 static const char *rp, reserved[] =
535 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
536 char *z = strchr(name, '.');
539 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
542 /* Track which names have been resolved
543 * and only report each one once. */
544 static unsigned reported;
545 unsigned mask = 1U<<(rp-reserved);
546 if (!(reported & mask)) {
548 dprintf(1, "\t%s => %s (%p)\n",
557 if (!strcmp(name, ldso->name)) is_self = 1;
562 tail = ldso->next ? ldso->next : ldso;
566 if (strchr(name, '/')) {
568 fd = open(name, O_RDONLY|O_CLOEXEC);
570 /* Search for the name to see if it's already loaded */
571 for (p=head->next; p; p=p->next) {
572 if (p->shortname && !strcmp(p->shortname, name)) {
577 if (strlen(name) > NAME_MAX) return 0;
579 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
580 for (p=needed_by; fd < 0 && p; p=p->needed_by)
581 if (!fixup_rpath(p, buf, sizeof buf))
582 fd = path_open(name, p->rpath, buf, sizeof buf);
587 if (ldso->name[0]=='/') {
589 for (s=t=z=ldso->name; *s; s++)
590 if (*s=='/') z=t, t=s;
591 prefix_len = z-ldso->name;
592 if (prefix_len < PATH_MAX)
599 char etc_ldso_path[prefix_len + 1
600 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
601 snprintf(etc_ldso_path, sizeof etc_ldso_path,
602 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
603 (int)prefix_len, prefix);
604 FILE *f = fopen(etc_ldso_path, "rbe");
606 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
613 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
614 fd = path_open(name, sys_path, buf, sizeof buf);
618 if (fd < 0) return 0;
619 if (fstat(fd, &st) < 0) {
623 for (p=head->next; p; p=p->next) {
624 if (p->dev == st.st_dev && p->ino == st.st_ino) {
625 /* If this library was previously loaded with a
626 * pathname but a search found the same inode,
627 * setup its shortname so it can be found by name. */
628 if (!p->shortname && pathname != name)
629 p->shortname = strrchr(p->name, '/')+1;
635 map = noload ? 0 : map_library(fd, &temp_dso);
639 /* Allocate storage for the new DSO. When there is TLS, this
640 * storage must include a reservation for all pre-existing
641 * threads to obtain copies of both the new TLS, and an
642 * extended DTV capable of storing an additional slot for
643 * the newly-loaded DSO. */
644 alloc_size = sizeof *p + strlen(pathname) + 1;
645 if (runtime && temp_dso.tls_image) {
646 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
647 + sizeof(void *) * (tls_cnt+3);
648 n_th = libc.threads_minus_1 + 1;
649 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
650 else alloc_size += n_th * per_th;
652 p = calloc(1, alloc_size);
654 munmap(map, temp_dso.map_len);
657 memcpy(p, &temp_dso, sizeof temp_dso);
662 p->needed_by = needed_by;
664 strcpy(p->name, pathname);
665 /* Add a shortname only if name arg was not an explicit pathname. */
666 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
668 if (runtime && !__pthread_self_init()) {
669 munmap(map, p->map_len);
673 p->tls_id = ++tls_cnt;
674 tls_align = MAXP2(tls_align, p->tls_align);
676 p->tls_offset = tls_offset + ( (tls_align-1) &
677 -(tls_offset + (uintptr_t)p->tls_image) );
678 tls_offset += p->tls_size;
680 tls_offset += p->tls_size + p->tls_align - 1;
681 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
683 p->tls_offset = tls_offset;
685 p->new_dtv = (void *)(-sizeof(size_t) &
686 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
687 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
694 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
699 static void load_deps(struct dso *p)
702 struct dso ***deps = &p->deps, **tmp, *dep;
703 for (; p; p=p->next) {
704 for (i=0; p->dynv[i]; i+=2) {
705 if (p->dynv[i] != DT_NEEDED) continue;
706 dep = load_library(p->strings + p->dynv[i+1], p);
708 snprintf(errbuf, sizeof errbuf,
709 "Error loading shared library %s: %m (needed by %s)",
710 p->strings + p->dynv[i+1], p->name);
711 if (runtime) longjmp(*rtld_fail, 1);
712 dprintf(2, "%s\n", errbuf);
717 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
718 if (!tmp) longjmp(*rtld_fail, 1);
727 static void load_preload(char *s)
732 for ( ; *s && isspace(*s); s++);
733 for (z=s; *z && !isspace(*z); z++);
741 static void make_global(struct dso *p)
743 for (; p; p=p->next) p->global = 1;
746 static void reloc_all(struct dso *p)
748 size_t dyn[DYN_CNT] = {0};
749 for (; p; p=p->next) {
750 if (p->relocated) continue;
751 decode_vec(p->dynv, dyn, DYN_CNT);
752 #ifdef NEED_ARCH_RELOCS
753 do_arch_relocs(p, head);
755 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
756 2+(dyn[DT_PLTREL]==DT_RELA));
757 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
758 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
763 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
765 for (; cnt--; ph = (void *)((char *)ph + stride))
766 if (ph->p_type == PT_DYNAMIC)
771 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
773 size_t min_addr = -1, max_addr = 0;
774 for (; cnt--; ph = (void *)((char *)ph + stride)) {
775 if (ph->p_type != PT_LOAD) continue;
776 if (ph->p_vaddr < min_addr)
777 min_addr = ph->p_vaddr;
778 if (ph->p_vaddr+ph->p_memsz > max_addr)
779 max_addr = ph->p_vaddr+ph->p_memsz;
781 min_addr &= -PAGE_SIZE;
782 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
783 p->map = p->base + min_addr;
784 p->map_len = max_addr - min_addr;
787 static void do_fini()
790 size_t dyn[DYN_CNT] = {0};
791 for (p=fini_head; p; p=p->fini_next) {
792 if (!p->constructed) continue;
793 decode_vec(p->dynv, dyn, DYN_CNT);
794 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
795 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
796 size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
797 while (n--) ((void (*)(void))*--fn)();
799 #ifndef NO_LEGACY_INITFINI
800 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
801 ((void (*)(void))(p->base + dyn[DT_FINI]))();
806 static void do_init_fini(struct dso *p)
808 size_t dyn[DYN_CNT] = {0};
809 int need_locking = libc.threads_minus_1;
810 /* Allow recursive calls that arise when a library calls
811 * dlopen from one of its constructors, but block any
812 * other threads until all ctors have finished. */
813 if (need_locking) pthread_mutex_lock(&init_fini_lock);
814 for (; p; p=p->prev) {
815 if (p->constructed) continue;
817 decode_vec(p->dynv, dyn, DYN_CNT);
818 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
819 p->fini_next = fini_head;
822 #ifndef NO_LEGACY_INITFINI
823 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
824 ((void (*)(void))(p->base + dyn[DT_INIT]))();
826 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
827 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
828 size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
829 while (n--) ((void (*)(void))*fn++)();
831 if (!need_locking && libc.threads_minus_1) {
833 pthread_mutex_lock(&init_fini_lock);
836 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
839 void _dl_debug_state(void)
845 pthread_t self = __pthread_self();
847 for (p=head; p; p=p->next) {
848 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
849 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
850 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
851 p->tls_size - p->tls_len);
852 if (p->tls_id == (size_t)self->dtv[0]) break;
856 void *__copy_tls(unsigned char *mem)
861 if (!tls_cnt) return mem;
863 void **dtv = (void *)mem;
864 dtv[0] = (void *)tls_cnt;
867 mem += sizeof(void *) * (tls_cnt+1);
868 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
870 mem += sizeof(struct pthread);
872 for (p=head; p; p=p->next) {
873 if (!p->tls_id) continue;
874 dtv[p->tls_id] = mem + p->tls_offset;
875 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
878 mem += libc.tls_size - sizeof(struct pthread);
879 mem -= (uintptr_t)mem & (tls_align-1);
882 for (p=head; p; p=p->next) {
883 if (!p->tls_id) continue;
884 dtv[p->tls_id] = mem - p->tls_offset;
885 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
892 void *__tls_get_addr(size_t *v)
894 pthread_t self = __pthread_self();
895 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
896 return (char *)self->dtv[v[0]]+v[1];
898 /* Block signals to make accessing new TLS async-signal-safe */
900 pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
901 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
902 pthread_sigmask(SIG_SETMASK, &set, 0);
903 return (char *)self->dtv[v[0]]+v[1];
906 /* This is safe without any locks held because, if the caller
907 * is able to request the Nth entry of the DTV, the DSO list
908 * must be valid at least that far out and it was synchronized
909 * at program startup or by an already-completed call to dlopen. */
911 for (p=head; p->tls_id != v[0]; p=p->next);
913 /* Get new DTV space from new DSO if needed */
914 if (v[0] > (size_t)self->dtv[0]) {
915 void **newdtv = p->new_dtv +
916 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
917 memcpy(newdtv, self->dtv,
918 ((size_t)self->dtv[0]+1) * sizeof(void *));
919 newdtv[0] = (void *)v[0];
923 /* Get new TLS memory from new DSO */
924 unsigned char *mem = p->new_tls +
925 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
926 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
927 self->dtv[v[0]] = mem;
928 memcpy(mem, p->tls_image, p->tls_len);
929 pthread_sigmask(SIG_SETMASK, &set, 0);
933 static void update_tls_size()
935 libc.tls_size = ALIGN(
936 (1+tls_cnt) * sizeof(void *) +
938 sizeof(struct pthread) +
943 void *__dynlink(int argc, char **argv)
945 size_t aux[AUX_CNT] = {0};
949 static struct dso builtin_dsos[3];
950 struct dso *const app = builtin_dsos+0;
951 struct dso *const lib = builtin_dsos+1;
952 struct dso *const vdso = builtin_dsos+2;
956 char **envp = argv+argc+1;
958 /* Find aux vector just past environ[] */
959 for (i=argc+1; argv[i]; i++)
960 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
961 env_path = argv[i]+16;
962 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
963 env_preload = argv[i]+11;
964 auxv = (void *)(argv+i+1);
966 decode_vec(auxv, aux, AUX_CNT);
968 /* Only trust user/env if kernel says we're not suid/sgid */
969 if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
970 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
976 /* If the dynamic linker was invoked as a program itself, AT_BASE
977 * will not be set. In that case, we assume the base address is
978 * the start of the page containing the PHDRs; I don't know any
979 * better approach... */
981 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
982 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
985 /* The dynamic linker load address is passed by the kernel
986 * in the AUX vector, so this is easy. */
987 lib->base = (void *)aux[AT_BASE];
988 lib->name = lib->shortname = "libc.so";
990 lib->kernel_mapped = 1;
991 ehdr = (void *)lib->base;
992 lib->phnum = ehdr->e_phnum;
993 lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
994 find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
995 lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
996 ehdr->e_phnum, ehdr->e_phentsize));
1000 size_t interp_off = 0;
1001 size_t tls_image = 0;
1002 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1003 app->phdr = phdr = (void *)aux[AT_PHDR];
1004 app->phnum = aux[AT_PHNUM];
1005 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1006 if (phdr->p_type == PT_PHDR)
1007 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1008 else if (phdr->p_type == PT_INTERP)
1009 interp_off = (size_t)phdr->p_vaddr;
1010 else if (phdr->p_type == PT_TLS) {
1011 tls_image = phdr->p_vaddr;
1012 app->tls_len = phdr->p_filesz;
1013 app->tls_size = phdr->p_memsz;
1014 app->tls_align = phdr->p_align;
1017 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1018 if (interp_off) lib->name = (char *)app->base + interp_off;
1019 app->name = argv[0];
1020 app->kernel_mapped = 1;
1021 app->dynv = (void *)(app->base + find_dyn(
1022 (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
1023 find_map_range((void *)aux[AT_PHDR],
1024 aux[AT_PHNUM], aux[AT_PHENT], app);
1027 char *ldname = argv[0];
1028 size_t l = strlen(ldname);
1029 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1030 *argv++ = (void *)-1;
1031 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
1033 dprintf(2, "musl libc/dynamic program loader\n");
1034 dprintf(2, "usage: %s pathname%s\n", ldname,
1035 ldd_mode ? "" : " [args]");
1038 fd = open(argv[0], O_RDONLY);
1040 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1044 ehdr = (void *)map_library(fd, app);
1046 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1052 app->name = argv[0];
1053 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1054 /* Find the name that would have been used for the dynamic
1055 * linker had ldd not taken its place. */
1057 for (i=0; i<app->phnum; i++) {
1058 if (app->phdr[i].p_type == PT_INTERP)
1059 lib->name = (void *)(app->base
1060 + app->phdr[i].p_vaddr);
1062 dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1065 if (app->tls_size) {
1066 app->tls_id = tls_cnt = 1;
1068 app->tls_offset = 0;
1069 tls_offset = app->tls_size
1070 + ( -((uintptr_t)app->tls_image + app->tls_size)
1071 & (app->tls_align-1) );
1073 tls_offset = app->tls_offset = app->tls_size
1074 + ( -((uintptr_t)app->tls_image + app->tls_size)
1075 & (app->tls_align-1) );
1077 tls_align = MAXP2(tls_align, app->tls_align);
1082 /* Attach to vdso, if provided by the kernel */
1083 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1084 ehdr = (void *)vdso_base;
1085 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1086 vdso->phnum = ehdr->e_phnum;
1087 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1088 if (phdr->p_type == PT_DYNAMIC)
1089 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1090 if (phdr->p_type == PT_LOAD)
1091 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1094 vdso->shortname = "linux-gate.so.1";
1101 /* Initial dso chain consists only of the app. We temporarily
1102 * append the dynamic linker/libc so we can relocate it, then
1103 * restore the initial chain in preparation for loading third
1104 * party libraries (preload/needed). */
1111 /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1113 /* Donate unused parts of app and library mapping to malloc */
1114 reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
1115 ehdr = (void *)lib->base;
1116 reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
1117 ehdr->e_phentsize, ehdr->e_phnum);
1119 /* Load preload/needed libraries, add their symbols to the global
1120 * namespace, and perform all remaining relocations. The main
1121 * program must be relocated LAST since it may contain copy
1122 * relocations which depend on libraries' relocations. */
1123 if (env_preload) load_preload(env_preload);
1127 reloc_all(app->next);
1132 void *mem = mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
1133 MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
1134 if (mem==MAP_FAILED ||
1135 !__install_initial_tls(__copy_tls(mem))) {
1136 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1137 argv[0], libc.tls_size);
1142 if (ldso_fail) _exit(127);
1143 if (ldd_mode) _exit(0);
1145 /* Switch to runtime mode: any further failures in the dynamic
1146 * linker are a reportable failure rather than a fatal startup
1147 * error. If the dynamic loader (dlopen) will not be used, free
1148 * all memory used by the dynamic linker. */
1151 #ifndef DYNAMIC_IS_RO
1152 for (i=0; app->dynv[i]; i+=2)
1153 if (app->dynv[i]==DT_DEBUG)
1154 app->dynv[i+1] = (size_t)&debug;
1157 debug.bp = _dl_debug_state;
1159 debug.base = lib->base;
1163 if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1164 __init_libc(envp, argv[0]);
1169 return (void *)aux[AT_ENTRY];
1172 void *dlopen(const char *file, int mode)
1174 struct dso *volatile p, *orig_tail, *next;
1175 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1180 if (!file) return head;
1182 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1183 pthread_rwlock_wrlock(&lock);
1187 orig_tls_cnt = tls_cnt;
1188 orig_tls_offset = tls_offset;
1189 orig_tls_align = tls_align;
1191 noload = mode & RTLD_NOLOAD;
1194 if (setjmp(*rtld_fail)) {
1195 /* Clean up anything new that was (partially) loaded */
1196 if (p && p->deps) for (i=0; p->deps[i]; i++)
1197 if (p->deps[i]->global < 0)
1198 p->deps[i]->global = 0;
1199 for (p=orig_tail->next; p; p=next) {
1201 munmap(p->map, p->map_len);
1205 tls_cnt = orig_tls_cnt;
1206 tls_offset = orig_tls_offset;
1207 tls_align = orig_tls_align;
1213 } else p = load_library(file, 0);
1216 snprintf(errbuf, sizeof errbuf, noload ?
1217 "Library %s is not already loaded" :
1218 "Error loading shared library %s: %m",
1224 /* First load handling */
1227 if (p->deps) for (i=0; p->deps[i]; i++)
1228 if (!p->deps[i]->global)
1229 p->deps[i]->global = -1;
1230 if (!p->global) p->global = -1;
1232 if (p->deps) for (i=0; p->deps[i]; i++)
1233 if (p->deps[i]->global < 0)
1234 p->deps[i]->global = 0;
1235 if (p->global < 0) p->global = 0;
1238 if (mode & RTLD_GLOBAL) {
1239 if (p->deps) for (i=0; p->deps[i]; i++)
1240 p->deps[i]->global = 1;
1246 if (ssp_used) __init_ssp(libc.auxv);
1253 pthread_rwlock_unlock(&lock);
1254 if (p) do_init_fini(orig_tail);
1255 pthread_setcancelstate(cs, 0);
1259 static int invalid_dso_handle(void *h)
1262 for (p=head; p; p=p->next) if (h==p) return 0;
1263 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1268 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1271 uint32_t h = 0, gh = 0;
1273 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1274 if (p == RTLD_DEFAULT) {
1276 } else if (p == RTLD_NEXT) {
1277 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1281 struct symdef def = find_sym(p, s, 0);
1282 if (!def.sym) goto failed;
1283 if ((def.sym->st_info&0xf) == STT_TLS)
1284 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1285 return def.dso->base + def.sym->st_value;
1287 if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1291 sym = gnu_lookup(s, gh, p);
1294 sym = sysv_lookup(s, h, p);
1296 if (sym && (sym->st_info&0xf) == STT_TLS)
1297 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1298 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1299 return p->base + sym->st_value;
1300 if (p->deps) for (i=0; p->deps[i]; i++) {
1301 if (p->deps[i]->ghashtab) {
1302 if (!gh) gh = gnu_hash(s);
1303 sym = gnu_lookup(s, gh, p->deps[i]);
1305 if (!h) h = sysv_hash(s);
1306 sym = sysv_lookup(s, h, p->deps[i]);
1308 if (sym && (sym->st_info&0xf) == STT_TLS)
1309 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1310 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1311 return p->deps[i]->base + sym->st_value;
1315 snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1319 int __dladdr(void *addr, Dl_info *info)
1329 pthread_rwlock_rdlock(&lock);
1330 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1331 pthread_rwlock_unlock(&lock);
1336 strings = p->strings;
1338 nsym = p->hashtab[1];
1342 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1343 sym += p->ghashtab[1];
1344 for (i = 0; i < p->ghashtab[0]; i++) {
1345 if (buckets[i] > nsym)
1349 nsym -= p->ghashtab[1];
1350 hashval = buckets + p->ghashtab[0] + nsym;
1352 while (!(*hashval++ & 1));
1356 for (; nsym; nsym--, sym++) {
1358 && (1<<(sym->st_info&0xf) & OK_TYPES)
1359 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1360 void *symaddr = p->base + sym->st_value;
1361 if (symaddr > addr || symaddr < best)
1364 bestname = strings + sym->st_name;
1365 if (addr == symaddr)
1370 if (!best) return 0;
1372 info->dli_fname = p->name;
1373 info->dli_fbase = p->base;
1374 info->dli_sname = bestname;
1375 info->dli_saddr = best;
1380 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1383 pthread_rwlock_rdlock(&lock);
1384 res = do_dlsym(p, s, ra);
1385 pthread_rwlock_unlock(&lock);
1389 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1391 struct dso *current;
1392 struct dl_phdr_info info;
1394 for(current = head; current;) {
1395 info.dlpi_addr = (uintptr_t)current->base;
1396 info.dlpi_name = current->name;
1397 info.dlpi_phdr = current->phdr;
1398 info.dlpi_phnum = current->phnum;
1399 info.dlpi_adds = gencnt;
1401 info.dlpi_tls_modid = current->tls_id;
1402 info.dlpi_tls_data = current->tls_image;
1404 ret = (callback)(&info, sizeof (info), data);
1406 if (ret != 0) break;
1408 pthread_rwlock_rdlock(&lock);
1409 current = current->next;
1410 pthread_rwlock_unlock(&lock);
1415 static int invalid_dso_handle(void *h)
1417 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1421 void *dlopen(const char *file, int mode)
1425 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1429 int __dladdr (void *addr, Dl_info *info)
1435 int __dlinfo(void *dso, int req, void *res)
1437 if (invalid_dso_handle(dso)) return -1;
1438 if (req != RTLD_DI_LINKMAP) {
1439 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1443 *(struct link_map **)res = dso;
1449 if (!errflag) return 0;
1454 int dlclose(void *p)
1456 return invalid_dso_handle(p);