18 #include "pthread_impl.h"
22 static char errbuf[128];
26 #if ULONG_MAX == 0xffffffff
27 typedef Elf32_Ehdr Ehdr;
28 typedef Elf32_Phdr Phdr;
29 typedef Elf32_Sym Sym;
30 #define R_TYPE(x) ((x)&255)
31 #define R_SYM(x) ((x)>>8)
33 typedef Elf64_Ehdr Ehdr;
34 typedef Elf64_Phdr Phdr;
35 typedef Elf64_Sym Sym;
36 #define R_TYPE(x) ((x)&0xffffffff)
37 #define R_SYM(x) ((x)>>32)
40 #define MAXP2(a,b) (-(-(a)&-(b)))
41 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
55 struct dso *next, *prev;
73 struct dso **deps, *needed_by;
74 char *rpath_orig, *rpath;
76 size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
77 size_t relro_start, relro_end;
79 unsigned char *new_tls;
80 int new_dtv_idx, new_tls_idx;
81 struct dso *fini_next;
93 void __init_ssp(size_t *);
94 int __init_tp(void *);
95 void __init_libc(char **, char *);
97 const char *__libc_get_version(void);
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 };
112 static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
114 struct debug *_dl_debug_addr = &debug;
119 static void decode_vec(size_t *v, size_t *a, size_t cnt)
121 memset(a, 0, cnt*sizeof(size_t));
122 for (; v[0]; v+=2) if (v[0]<cnt) {
128 static int search_vec(size_t *v, size_t *r, size_t key)
130 for (; v[0]!=key; v+=2)
136 static uint32_t sysv_hash(const char *s0)
138 const unsigned char *s = (void *)s0;
144 return h & 0xfffffff;
147 static uint32_t gnu_hash(const char *s0)
149 const unsigned char *s = (void *)s0;
150 uint_fast32_t h = 5381;
156 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
159 Sym *syms = dso->syms;
160 uint32_t *hashtab = dso->hashtab;
161 char *strings = dso->strings;
162 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
163 if ((!dso->versym || dso->versym[i] >= 0)
164 && (!strcmp(s, strings+syms[i].st_name)))
170 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
172 Sym *syms = dso->syms;
173 char *strings = dso->strings;
174 uint32_t *hashtab = dso->ghashtab;
175 uint32_t nbuckets = hashtab[0];
176 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
179 uint32_t i = buckets[h1 % nbuckets];
183 hashval = buckets + nbuckets + (i - hashtab[1]);
185 for (h1 |= 1; ; i++) {
187 if ((!dso->versym || dso->versym[i] >= 0)
188 && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
196 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
197 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
199 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
201 uint32_t h = 0, gh = 0;
202 struct symdef def = {0};
205 if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
208 if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
210 for (; dso; dso=dso->next) {
212 if (!dso->global) continue;
214 if (!gh) gh = gnu_hash(s);
215 sym = gnu_lookup(s, gh, dso);
217 if (!h) h = sysv_hash(s);
218 sym = sysv_lookup(s, h, dso);
222 if (need_def || (sym->st_info&0xf) == STT_TLS)
225 if ((sym->st_info&0xf) != STT_TLS)
227 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
228 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
230 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
233 if (sym->st_info>>4 == STB_GLOBAL) break;
238 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
240 unsigned char *base = dso->base;
241 Sym *syms = dso->syms;
242 char *strings = dso->strings;
250 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
251 type = R_TYPE(rel[1]);
252 sym_index = R_SYM(rel[1]);
254 sym = syms + sym_index;
255 name = strings + sym->st_name;
256 ctx = IS_COPY(type) ? head->next : head;
257 def = find_sym(ctx, name, IS_PLT(type));
258 if (!def.sym && (sym->st_shndx != SHN_UNDEF
259 || sym->st_info>>4 != STB_WEAK)) {
260 snprintf(errbuf, sizeof errbuf,
261 "Error relocating %s: %s: symbol not found",
263 if (runtime) longjmp(*rtld_fail, 1);
264 dprintf(2, "%s\n", errbuf);
273 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
274 stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
275 def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
279 /* A huge hack: to make up for the wastefulness of shared libraries
280 * needing at least a page of dirty memory even if they have no global
281 * data, we reclaim the gaps at the beginning and end of writable maps
282 * and "donate" them to the heap by setting up minimal malloc
283 * structures and then freeing them. */
285 static void reclaim(struct dso *dso, size_t start, size_t end)
288 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
289 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
290 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
291 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
292 if (start>end || end-start < 4*sizeof(size_t)) return;
293 a = (size_t *)(dso->base + start);
294 z = (size_t *)(dso->base + end);
296 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
301 static void reclaim_gaps(struct dso *dso, Phdr *ph, size_t phent, size_t phcnt)
303 for (; phcnt--; ph=(void *)((char *)ph+phent)) {
304 if (ph->p_type!=PT_LOAD) continue;
305 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
306 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
307 reclaim(dso, ph->p_vaddr+ph->p_memsz,
308 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
312 static void *map_library(int fd, struct dso *dso)
314 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
315 void *allocated_buf=0;
317 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
318 size_t this_min, this_max;
323 unsigned char *map=MAP_FAILED, *base;
328 ssize_t l = read(fd, buf, sizeof buf);
331 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
333 phsize = eh->e_phentsize * eh->e_phnum;
334 if (phsize > sizeof buf - sizeof *eh) {
335 allocated_buf = malloc(phsize);
336 if (!allocated_buf) return 0;
337 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
338 if (l < 0) goto error;
339 if (l != phsize) goto noexec;
340 ph = ph0 = allocated_buf;
341 } else if (eh->e_phoff + phsize > l) {
342 l = pread(fd, buf+1, phsize, eh->e_phoff);
343 if (l < 0) goto error;
344 if (l != phsize) goto noexec;
345 ph = ph0 = (void *)(buf + 1);
347 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
349 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
350 if (ph->p_type == PT_DYNAMIC)
352 else if (ph->p_type == PT_TLS) {
353 tls_image = ph->p_vaddr;
354 dso->tls_align = ph->p_align;
355 dso->tls_len = ph->p_filesz;
356 dso->tls_size = ph->p_memsz;
357 } else if (ph->p_type == PT_GNU_RELRO) {
358 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
359 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
361 if (ph->p_type != PT_LOAD) continue;
362 if (ph->p_vaddr < addr_min) {
363 addr_min = ph->p_vaddr;
364 off_start = ph->p_offset;
365 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
366 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
367 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
369 if (ph->p_vaddr+ph->p_memsz > addr_max) {
370 addr_max = ph->p_vaddr+ph->p_memsz;
373 if (!dyn) goto noexec;
374 addr_max += PAGE_SIZE-1;
375 addr_max &= -PAGE_SIZE;
376 addr_min &= -PAGE_SIZE;
377 off_start &= -PAGE_SIZE;
378 map_len = addr_max - addr_min + off_start;
379 /* The first time, we map too much, possibly even more than
380 * the length of the file. This is okay because we will not
381 * use the invalid part; we just need to reserve the right
382 * amount of virtual address space to map over later. */
383 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
384 if (map==MAP_FAILED) goto error;
385 /* If the loaded file is not relocatable and the requested address is
386 * not available, then the load operation must fail. */
387 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
391 base = map - addr_min;
394 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
395 if (ph->p_type != PT_LOAD) continue;
396 /* Check if the programs headers are in this load segment, and
397 * if so, record the address for use by dl_iterate_phdr. */
398 if (!dso->phdr && eh->e_phoff >= ph->p_offset
399 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
400 dso->phdr = (void *)(base + ph->p_vaddr
401 + (eh->e_phoff-ph->p_offset));
402 dso->phnum = eh->e_phnum;
404 /* Reuse the existing mapping for the lowest-address LOAD */
405 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
406 this_min = ph->p_vaddr & -PAGE_SIZE;
407 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
408 off_start = ph->p_offset & -PAGE_SIZE;
409 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
410 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
411 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
412 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
414 if (ph->p_memsz > ph->p_filesz) {
415 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
416 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
417 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
418 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)
422 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
423 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
424 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
429 dso->map_len = map_len;
431 dso->dynv = (void *)(base+dyn);
432 if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
433 if (!runtime) reclaim_gaps(dso, ph0, eh->e_phentsize, eh->e_phnum);
439 if (map!=MAP_FAILED) munmap(map, map_len);
444 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
449 s += strspn(s, ":\n");
450 l = strcspn(s, ":\n");
451 if (l-1 >= INT_MAX) return -1;
452 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
454 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
459 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
462 const char *s, *t, *origin;
464 if (p->rpath) return 0;
465 if (!p->rpath_orig) return -1;
466 if (!strchr(p->rpath_orig, '$')) {
467 p->rpath = p->rpath_orig;
472 while ((t=strchr(s, '$'))) {
473 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
478 if (n > SSIZE_MAX/PATH_MAX) return -1;
480 if (p->kernel_mapped) {
481 /* $ORIGIN searches cannot be performed for the main program
482 * when it is suid/sgid/AT_SECURE. This is because the
483 * pathname is under the control of the caller of execve.
484 * For libraries, however, $ORIGIN can be processed safely
485 * since the library's pathname came from a trusted source
486 * (either system paths or a call to dlopen). */
489 l = readlink("/proc/self/exe", buf, buf_size);
497 t = strrchr(origin, '/');
498 l = t ? t-origin : 0;
499 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
500 if (!p->rpath) return -1;
504 while ((t=strchr(s, '$'))) {
507 memcpy(d, origin, l);
509 /* It was determined previously that the '$' is followed
510 * either by "ORIGIN" or "{ORIGIN}". */
511 s = t + 7 + 2*(t[1]=='{');
517 static void decode_dyn(struct dso *p)
519 size_t dyn[DYN_CNT] = {0};
520 decode_vec(p->dynv, dyn, DYN_CNT);
521 p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
522 p->strings = (void *)(p->base + dyn[DT_STRTAB]);
523 if (dyn[0]&(1<<DT_HASH))
524 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
525 if (dyn[0]&(1<<DT_RPATH))
526 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
527 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
528 p->ghashtab = (void *)(p->base + *dyn);
529 if (search_vec(p->dynv, dyn, DT_VERSYM))
530 p->versym = (void *)(p->base + *dyn);
533 static struct dso *load_library(const char *name, struct dso *needed_by)
535 char buf[2*NAME_MAX+2];
536 const char *pathname;
538 struct dso *p, temp_dso = {0};
545 /* Catch and block attempts to reload the implementation itself */
546 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
547 static const char *rp, reserved[] =
548 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
549 char *z = strchr(name, '.');
552 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
555 /* Track which names have been resolved
556 * and only report each one once. */
557 static unsigned reported;
558 unsigned mask = 1U<<(rp-reserved);
559 if (!(reported & mask)) {
561 dprintf(1, "\t%s => %s (%p)\n",
570 if (!strcmp(name, ldso->name)) is_self = 1;
575 tail = ldso->next ? ldso->next : ldso;
579 if (strchr(name, '/')) {
581 fd = open(name, O_RDONLY|O_CLOEXEC);
583 /* Search for the name to see if it's already loaded */
584 for (p=head->next; p; p=p->next) {
585 if (p->shortname && !strcmp(p->shortname, name)) {
590 if (strlen(name) > NAME_MAX) return 0;
592 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
593 for (p=needed_by; fd < 0 && p; p=p->needed_by)
594 if (!fixup_rpath(p, buf, sizeof buf))
595 fd = path_open(name, p->rpath, buf, sizeof buf);
600 if (ldso->name[0]=='/') {
602 for (s=t=z=ldso->name; *s; s++)
603 if (*s=='/') z=t, t=s;
604 prefix_len = z-ldso->name;
605 if (prefix_len < PATH_MAX)
612 char etc_ldso_path[prefix_len + 1
613 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
614 snprintf(etc_ldso_path, sizeof etc_ldso_path,
615 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
616 (int)prefix_len, prefix);
617 FILE *f = fopen(etc_ldso_path, "rbe");
619 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
624 } else if (errno != ENOENT) {
628 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
629 fd = path_open(name, sys_path, buf, sizeof buf);
633 if (fd < 0) return 0;
634 if (fstat(fd, &st) < 0) {
638 for (p=head->next; p; p=p->next) {
639 if (p->dev == st.st_dev && p->ino == st.st_ino) {
640 /* If this library was previously loaded with a
641 * pathname but a search found the same inode,
642 * setup its shortname so it can be found by name. */
643 if (!p->shortname && pathname != name)
644 p->shortname = strrchr(p->name, '/')+1;
650 map = noload ? 0 : map_library(fd, &temp_dso);
654 /* Allocate storage for the new DSO. When there is TLS, this
655 * storage must include a reservation for all pre-existing
656 * threads to obtain copies of both the new TLS, and an
657 * extended DTV capable of storing an additional slot for
658 * the newly-loaded DSO. */
659 alloc_size = sizeof *p + strlen(pathname) + 1;
660 if (runtime && temp_dso.tls_image) {
661 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
662 + sizeof(void *) * (tls_cnt+3);
663 n_th = libc.threads_minus_1 + 1;
664 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
665 else alloc_size += n_th * per_th;
667 p = calloc(1, alloc_size);
669 munmap(map, temp_dso.map_len);
672 memcpy(p, &temp_dso, sizeof temp_dso);
677 p->needed_by = needed_by;
679 strcpy(p->name, pathname);
680 /* Add a shortname only if name arg was not an explicit pathname. */
681 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
683 if (runtime && !libc.has_thread_pointer) {
684 munmap(map, p->map_len);
689 p->tls_id = ++tls_cnt;
690 tls_align = MAXP2(tls_align, p->tls_align);
692 p->tls_offset = tls_offset + ( (tls_align-1) &
693 -(tls_offset + (uintptr_t)p->tls_image) );
694 tls_offset += p->tls_size;
696 tls_offset += p->tls_size + p->tls_align - 1;
697 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
699 p->tls_offset = tls_offset;
701 p->new_dtv = (void *)(-sizeof(size_t) &
702 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
703 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
710 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
715 static void load_deps(struct dso *p)
718 struct dso ***deps = &p->deps, **tmp, *dep;
719 for (; p; p=p->next) {
720 for (i=0; p->dynv[i]; i+=2) {
721 if (p->dynv[i] != DT_NEEDED) continue;
722 dep = load_library(p->strings + p->dynv[i+1], p);
724 snprintf(errbuf, sizeof errbuf,
725 "Error loading shared library %s: %m (needed by %s)",
726 p->strings + p->dynv[i+1], p->name);
727 if (runtime) longjmp(*rtld_fail, 1);
728 dprintf(2, "%s\n", errbuf);
733 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
734 if (!tmp) longjmp(*rtld_fail, 1);
743 static void load_preload(char *s)
748 for ( ; *s && isspace(*s); s++);
749 for (z=s; *z && !isspace(*z); z++);
757 static void make_global(struct dso *p)
759 for (; p; p=p->next) p->global = 1;
762 static void reloc_all(struct dso *p)
764 size_t dyn[DYN_CNT] = {0};
765 for (; p; p=p->next) {
766 if (p->relocated) continue;
767 decode_vec(p->dynv, dyn, DYN_CNT);
768 #ifdef NEED_ARCH_RELOCS
769 do_arch_relocs(p, head);
771 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
772 2+(dyn[DT_PLTREL]==DT_RELA));
773 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
774 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
776 if (p->relro_start != p->relro_end &&
777 mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) {
778 snprintf(errbuf, sizeof errbuf,
779 "Error relocating %s: RELRO protection failed",
781 if (runtime) longjmp(*rtld_fail, 1);
782 dprintf(2, "%s\n", errbuf);
790 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
792 for (; cnt--; ph = (void *)((char *)ph + stride))
793 if (ph->p_type == PT_DYNAMIC)
798 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
800 size_t min_addr = -1, max_addr = 0;
801 for (; cnt--; ph = (void *)((char *)ph + stride)) {
802 if (ph->p_type == PT_GNU_RELRO) {
803 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
804 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
806 if (ph->p_type != PT_LOAD) continue;
807 if (ph->p_vaddr < min_addr)
808 min_addr = ph->p_vaddr;
809 if (ph->p_vaddr+ph->p_memsz > max_addr)
810 max_addr = ph->p_vaddr+ph->p_memsz;
812 min_addr &= -PAGE_SIZE;
813 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
814 p->map = p->base + min_addr;
815 p->map_len = max_addr - min_addr;
818 static void do_fini()
821 size_t dyn[DYN_CNT] = {0};
822 for (p=fini_head; p; p=p->fini_next) {
823 if (!p->constructed) continue;
824 decode_vec(p->dynv, dyn, DYN_CNT);
825 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
826 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
827 size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
828 while (n--) ((void (*)(void))*--fn)();
830 #ifndef NO_LEGACY_INITFINI
831 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
832 ((void (*)(void))(p->base + dyn[DT_FINI]))();
837 static void do_init_fini(struct dso *p)
839 size_t dyn[DYN_CNT] = {0};
840 int need_locking = libc.threads_minus_1;
841 /* Allow recursive calls that arise when a library calls
842 * dlopen from one of its constructors, but block any
843 * other threads until all ctors have finished. */
844 if (need_locking) pthread_mutex_lock(&init_fini_lock);
845 for (; p; p=p->prev) {
846 if (p->constructed) continue;
848 decode_vec(p->dynv, dyn, DYN_CNT);
849 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
850 p->fini_next = fini_head;
853 #ifndef NO_LEGACY_INITFINI
854 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
855 ((void (*)(void))(p->base + dyn[DT_INIT]))();
857 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
858 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
859 size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
860 while (n--) ((void (*)(void))*fn++)();
862 if (!need_locking && libc.threads_minus_1) {
864 pthread_mutex_lock(&init_fini_lock);
867 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
870 void _dl_debug_state(void)
876 pthread_t self = __pthread_self();
878 for (p=head; p; p=p->next) {
879 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
880 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
881 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
882 p->tls_size - p->tls_len);
883 if (p->tls_id == (size_t)self->dtv[0]) break;
887 void *__copy_tls(unsigned char *mem)
892 void **dtv = (void *)mem;
893 dtv[0] = (void *)tls_cnt;
895 td = (void *)(dtv+1);
901 mem += sizeof(void *) * (tls_cnt+1);
902 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
904 mem += sizeof(struct pthread);
906 for (p=head; p; p=p->next) {
907 if (!p->tls_id) continue;
908 dtv[p->tls_id] = mem + p->tls_offset;
909 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
912 mem += libc.tls_size - sizeof(struct pthread);
913 mem -= (uintptr_t)mem & (tls_align-1);
916 for (p=head; p; p=p->next) {
917 if (!p->tls_id) continue;
918 dtv[p->tls_id] = mem - p->tls_offset;
919 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
926 void *__tls_get_addr(size_t *v)
928 pthread_t self = __pthread_self();
929 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
930 return (char *)self->dtv[v[0]]+v[1];
932 /* Block signals to make accessing new TLS async-signal-safe */
934 pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
935 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
936 pthread_sigmask(SIG_SETMASK, &set, 0);
937 return (char *)self->dtv[v[0]]+v[1];
940 /* This is safe without any locks held because, if the caller
941 * is able to request the Nth entry of the DTV, the DSO list
942 * must be valid at least that far out and it was synchronized
943 * at program startup or by an already-completed call to dlopen. */
945 for (p=head; p->tls_id != v[0]; p=p->next);
947 /* Get new DTV space from new DSO if needed */
948 if (v[0] > (size_t)self->dtv[0]) {
949 void **newdtv = p->new_dtv +
950 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
951 memcpy(newdtv, self->dtv,
952 ((size_t)self->dtv[0]+1) * sizeof(void *));
953 newdtv[0] = (void *)v[0];
957 /* Get new TLS memory from new DSO */
958 unsigned char *mem = p->new_tls +
959 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
960 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
961 self->dtv[v[0]] = mem;
962 memcpy(mem, p->tls_image, p->tls_len);
963 pthread_sigmask(SIG_SETMASK, &set, 0);
967 static void update_tls_size()
969 libc.tls_size = ALIGN(
970 (1+tls_cnt) * sizeof(void *) +
972 sizeof(struct pthread) +
977 void *__dynlink(int argc, char **argv)
979 size_t aux[AUX_CNT] = {0};
983 static struct dso builtin_dsos[3];
984 struct dso *const app = builtin_dsos+0;
985 struct dso *const lib = builtin_dsos+1;
986 struct dso *const vdso = builtin_dsos+2;
990 char **envp = argv+argc+1;
993 /* Find aux vector just past environ[] */
994 for (i=argc+1; argv[i]; i++)
995 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
996 env_path = argv[i]+16;
997 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
998 env_preload = argv[i]+11;
999 auxv = (void *)(argv+i+1);
1001 decode_vec(auxv, aux, AUX_CNT);
1003 /* Only trust user/env if kernel says we're not suid/sgid */
1004 if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1005 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
1010 libc.page_size = aux[AT_PAGESZ];
1012 /* If the dynamic linker was invoked as a program itself, AT_BASE
1013 * will not be set. In that case, we assume the base address is
1014 * the start of the page containing the PHDRs; I don't know any
1015 * better approach... */
1016 if (!aux[AT_BASE]) {
1017 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
1018 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
1021 /* The dynamic linker load address is passed by the kernel
1022 * in the AUX vector, so this is easy. */
1023 lib->base = (void *)aux[AT_BASE];
1024 lib->name = lib->shortname = "libc.so";
1026 lib->kernel_mapped = 1;
1027 ehdr = (void *)lib->base;
1028 lib->phnum = ehdr->e_phnum;
1029 lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1030 find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
1031 lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
1032 ehdr->e_phnum, ehdr->e_phentsize));
1036 size_t interp_off = 0;
1037 size_t tls_image = 0;
1038 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1039 app->phdr = phdr = (void *)aux[AT_PHDR];
1040 app->phnum = aux[AT_PHNUM];
1041 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1042 if (phdr->p_type == PT_PHDR)
1043 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1044 else if (phdr->p_type == PT_INTERP)
1045 interp_off = (size_t)phdr->p_vaddr;
1046 else if (phdr->p_type == PT_TLS) {
1047 tls_image = phdr->p_vaddr;
1048 app->tls_len = phdr->p_filesz;
1049 app->tls_size = phdr->p_memsz;
1050 app->tls_align = phdr->p_align;
1053 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1054 if (interp_off) lib->name = (char *)app->base + interp_off;
1055 if ((aux[0] & (1UL<<AT_EXECFN))
1056 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1057 app->name = (char *)aux[AT_EXECFN];
1059 app->name = argv[0];
1060 app->kernel_mapped = 1;
1061 app->dynv = (void *)(app->base + find_dyn(
1062 (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
1063 find_map_range((void *)aux[AT_PHDR],
1064 aux[AT_PHNUM], aux[AT_PHENT], app);
1067 char *ldname = argv[0];
1068 size_t l = strlen(ldname);
1069 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1070 *argv++ = (void *)-1;
1071 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
1073 dprintf(2, "musl libc\n"
1075 "Dynamic Program Loader\n"
1076 "Usage: %s [--] pathname%s\n",
1077 __libc_get_version(), ldname,
1078 ldd_mode ? "" : " [args]");
1081 fd = open(argv[0], O_RDONLY);
1083 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1087 ehdr = (void *)map_library(fd, app);
1089 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1095 app->name = argv[0];
1096 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1097 /* Find the name that would have been used for the dynamic
1098 * linker had ldd not taken its place. */
1100 for (i=0; i<app->phnum; i++) {
1101 if (app->phdr[i].p_type == PT_INTERP)
1102 lib->name = (void *)(app->base
1103 + app->phdr[i].p_vaddr);
1105 dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1108 if (app->tls_size) {
1109 app->tls_id = tls_cnt = 1;
1111 app->tls_offset = 0;
1112 tls_offset = app->tls_size
1113 + ( -((uintptr_t)app->tls_image + app->tls_size)
1114 & (app->tls_align-1) );
1116 tls_offset = app->tls_offset = app->tls_size
1117 + ( -((uintptr_t)app->tls_image + app->tls_size)
1118 & (app->tls_align-1) );
1120 tls_align = MAXP2(tls_align, app->tls_align);
1125 /* Attach to vdso, if provided by the kernel */
1126 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1127 ehdr = (void *)vdso_base;
1128 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1129 vdso->phnum = ehdr->e_phnum;
1130 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1131 if (phdr->p_type == PT_DYNAMIC)
1132 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1133 if (phdr->p_type == PT_LOAD)
1134 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1137 vdso->shortname = "linux-gate.so.1";
1144 /* Initial dso chain consists only of the app. We temporarily
1145 * append the dynamic linker/libc so we can relocate it, then
1146 * restore the initial chain in preparation for loading third
1147 * party libraries (preload/needed). */
1154 /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1156 /* Donate unused parts of app and library mapping to malloc */
1157 reclaim_gaps(app, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
1158 ehdr = (void *)lib->base;
1159 reclaim_gaps(lib, (void *)(lib->base+ehdr->e_phoff),
1160 ehdr->e_phentsize, ehdr->e_phnum);
1162 /* Load preload/needed libraries, add their symbols to the global
1163 * namespace, and perform all remaining relocations. The main
1164 * program must be relocated LAST since it may contain copy
1165 * relocations which depend on libraries' relocations. */
1166 if (env_preload) load_preload(env_preload);
1170 #ifndef DYNAMIC_IS_RO
1171 for (i=0; app->dynv[i]; i+=2)
1172 if (app->dynv[i]==DT_DEBUG)
1173 app->dynv[i+1] = (size_t)&debug;
1176 reloc_all(app->next);
1180 if (libc.tls_size > sizeof builtin_tls) {
1181 initial_tls = calloc(libc.tls_size, 1);
1183 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1184 argv[0], libc.tls_size);
1188 initial_tls = builtin_tls;
1190 if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
1191 dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
1195 if (ldso_fail) _exit(127);
1196 if (ldd_mode) _exit(0);
1198 /* Switch to runtime mode: any further failures in the dynamic
1199 * linker are a reportable failure rather than a fatal startup
1200 * error. If the dynamic loader (dlopen) will not be used, free
1201 * all memory used by the dynamic linker. */
1205 debug.bp = _dl_debug_state;
1207 debug.base = lib->base;
1211 if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1212 __init_libc(envp, argv[0]);
1217 return (void *)aux[AT_ENTRY];
1220 void *dlopen(const char *file, int mode)
1222 struct dso *volatile p, *orig_tail, *next;
1223 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1228 if (!file) return head;
1230 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1231 pthread_rwlock_wrlock(&lock);
1235 orig_tls_cnt = tls_cnt;
1236 orig_tls_offset = tls_offset;
1237 orig_tls_align = tls_align;
1239 noload = mode & RTLD_NOLOAD;
1242 if (setjmp(*rtld_fail)) {
1243 /* Clean up anything new that was (partially) loaded */
1244 if (p && p->deps) for (i=0; p->deps[i]; i++)
1245 if (p->deps[i]->global < 0)
1246 p->deps[i]->global = 0;
1247 for (p=orig_tail->next; p; p=next) {
1249 munmap(p->map, p->map_len);
1253 tls_cnt = orig_tls_cnt;
1254 tls_offset = orig_tls_offset;
1255 tls_align = orig_tls_align;
1261 } else p = load_library(file, head);
1264 snprintf(errbuf, sizeof errbuf, noload ?
1265 "Library %s is not already loaded" :
1266 "Error loading shared library %s: %m",
1272 /* First load handling */
1275 if (p->deps) for (i=0; p->deps[i]; i++)
1276 if (!p->deps[i]->global)
1277 p->deps[i]->global = -1;
1278 if (!p->global) p->global = -1;
1280 if (p->deps) for (i=0; p->deps[i]; i++)
1281 if (p->deps[i]->global < 0)
1282 p->deps[i]->global = 0;
1283 if (p->global < 0) p->global = 0;
1286 if (mode & RTLD_GLOBAL) {
1287 if (p->deps) for (i=0; p->deps[i]; i++)
1288 p->deps[i]->global = 1;
1294 if (ssp_used) __init_ssp(libc.auxv);
1301 pthread_rwlock_unlock(&lock);
1302 if (p) do_init_fini(orig_tail);
1303 pthread_setcancelstate(cs, 0);
1307 static int invalid_dso_handle(void *h)
1310 for (p=head; p; p=p->next) if (h==p) return 0;
1311 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1316 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1319 uint32_t h = 0, gh = 0;
1321 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1322 if (p == RTLD_DEFAULT) {
1324 } else if (p == RTLD_NEXT) {
1325 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1329 struct symdef def = find_sym(p, s, 0);
1330 if (!def.sym) goto failed;
1331 if ((def.sym->st_info&0xf) == STT_TLS)
1332 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1333 return def.dso->base + def.sym->st_value;
1335 if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1339 sym = gnu_lookup(s, gh, p);
1342 sym = sysv_lookup(s, h, p);
1344 if (sym && (sym->st_info&0xf) == STT_TLS)
1345 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1346 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1347 return p->base + sym->st_value;
1348 if (p->deps) for (i=0; p->deps[i]; i++) {
1349 if (p->deps[i]->ghashtab) {
1350 if (!gh) gh = gnu_hash(s);
1351 sym = gnu_lookup(s, gh, p->deps[i]);
1353 if (!h) h = sysv_hash(s);
1354 sym = sysv_lookup(s, h, p->deps[i]);
1356 if (sym && (sym->st_info&0xf) == STT_TLS)
1357 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1358 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1359 return p->deps[i]->base + sym->st_value;
1363 snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1367 int __dladdr(const void *addr, Dl_info *info)
1377 pthread_rwlock_rdlock(&lock);
1378 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1379 pthread_rwlock_unlock(&lock);
1384 strings = p->strings;
1386 nsym = p->hashtab[1];
1390 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1391 sym += p->ghashtab[1];
1392 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1393 if (buckets[i] > nsym)
1397 nsym -= p->ghashtab[1];
1398 hashval = buckets + p->ghashtab[0] + nsym;
1400 while (!(*hashval++ & 1));
1404 for (; nsym; nsym--, sym++) {
1406 && (1<<(sym->st_info&0xf) & OK_TYPES)
1407 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1408 void *symaddr = p->base + sym->st_value;
1409 if (symaddr > addr || symaddr < best)
1412 bestname = strings + sym->st_name;
1413 if (addr == symaddr)
1418 if (!best) return 0;
1420 info->dli_fname = p->name;
1421 info->dli_fbase = p->base;
1422 info->dli_sname = bestname;
1423 info->dli_saddr = best;
1428 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1431 pthread_rwlock_rdlock(&lock);
1432 res = do_dlsym(p, s, ra);
1433 pthread_rwlock_unlock(&lock);
1437 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1439 struct dso *current;
1440 struct dl_phdr_info info;
1442 for(current = head; current;) {
1443 info.dlpi_addr = (uintptr_t)current->base;
1444 info.dlpi_name = current->name;
1445 info.dlpi_phdr = current->phdr;
1446 info.dlpi_phnum = current->phnum;
1447 info.dlpi_adds = gencnt;
1449 info.dlpi_tls_modid = current->tls_id;
1450 info.dlpi_tls_data = current->tls_image;
1452 ret = (callback)(&info, sizeof (info), data);
1454 if (ret != 0) break;
1456 pthread_rwlock_rdlock(&lock);
1457 current = current->next;
1458 pthread_rwlock_unlock(&lock);
1463 static int invalid_dso_handle(void *h)
1465 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1469 void *dlopen(const char *file, int mode)
1473 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1477 int __dladdr (const void *addr, Dl_info *info)
1483 int __dlinfo(void *dso, int req, void *res)
1485 if (invalid_dso_handle(dso)) return -1;
1486 if (req != RTLD_DI_LINKMAP) {
1487 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1491 *(struct link_map **)res = dso;
1497 if (!errflag) return 0;
1502 int dlclose(void *p)
1504 return invalid_dso_handle(p);