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;
78 unsigned char *new_tls;
79 int new_dtv_idx, new_tls_idx;
80 struct dso *fini_next;
92 void __init_ssp(size_t *);
93 int __init_tp(void *);
94 void __init_libc(char **, char *);
96 const char *__libc_get_version(void);
98 static struct dso *head, *tail, *ldso, *fini_head;
99 static char *env_path, *sys_path;
100 static unsigned long long gencnt;
104 static int ldso_fail;
106 static jmp_buf *rtld_fail;
107 static pthread_rwlock_t lock;
108 static struct debug debug;
109 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
110 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
111 static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
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_shndx != SHN_UNDEF
258 || sym->st_info>>4 != STB_WEAK)) {
259 snprintf(errbuf, sizeof errbuf,
260 "Error relocating %s: %s: symbol not found",
262 if (runtime) longjmp(*rtld_fail, 1);
263 dprintf(2, "%s\n", errbuf);
272 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
273 stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
274 def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
278 /* A huge hack: to make up for the wastefulness of shared libraries
279 * needing at least a page of dirty memory even if they have no global
280 * data, we reclaim the gaps at the beginning and end of writable maps
281 * and "donate" them to the heap by setting up minimal malloc
282 * structures and then freeing them. */
284 static void reclaim(unsigned char *base, size_t start, size_t end)
287 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
288 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
289 if (start>end || end-start < 4*sizeof(size_t)) return;
290 a = (size_t *)(base + start);
291 z = (size_t *)(base + end);
293 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
298 static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
300 for (; phcnt--; ph=(void *)((char *)ph+phent)) {
301 if (ph->p_type!=PT_LOAD) continue;
302 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
303 reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
304 reclaim(base, ph->p_vaddr+ph->p_memsz,
305 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
309 static void *map_library(int fd, struct dso *dso)
311 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
312 void *allocated_buf=0;
314 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
315 size_t this_min, this_max;
320 unsigned char *map=MAP_FAILED, *base;
325 ssize_t l = read(fd, buf, sizeof buf);
328 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
330 phsize = eh->e_phentsize * eh->e_phnum;
331 if (phsize > sizeof buf - sizeof *eh) {
332 allocated_buf = malloc(phsize);
333 if (!allocated_buf) return 0;
334 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
335 if (l < 0) goto error;
336 if (l != phsize) goto noexec;
337 ph = ph0 = allocated_buf;
338 } else if (eh->e_phoff + phsize > l) {
339 l = pread(fd, buf+1, phsize, eh->e_phoff);
340 if (l < 0) goto error;
341 if (l != phsize) goto noexec;
342 ph = ph0 = (void *)(buf + 1);
344 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
346 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
347 if (ph->p_type == PT_DYNAMIC)
349 if (ph->p_type == PT_TLS) {
350 tls_image = ph->p_vaddr;
351 dso->tls_align = ph->p_align;
352 dso->tls_len = ph->p_filesz;
353 dso->tls_size = ph->p_memsz;
355 if (ph->p_type != PT_LOAD) continue;
356 if (ph->p_vaddr < addr_min) {
357 addr_min = ph->p_vaddr;
358 off_start = ph->p_offset;
359 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
360 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
361 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
363 if (ph->p_vaddr+ph->p_memsz > addr_max) {
364 addr_max = ph->p_vaddr+ph->p_memsz;
367 if (!dyn) goto noexec;
368 addr_max += PAGE_SIZE-1;
369 addr_max &= -PAGE_SIZE;
370 addr_min &= -PAGE_SIZE;
371 off_start &= -PAGE_SIZE;
372 map_len = addr_max - addr_min + off_start;
373 /* The first time, we map too much, possibly even more than
374 * the length of the file. This is okay because we will not
375 * use the invalid part; we just need to reserve the right
376 * amount of virtual address space to map over later. */
377 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
378 if (map==MAP_FAILED) goto error;
379 /* If the loaded file is not relocatable and the requested address is
380 * not available, then the load operation must fail. */
381 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
385 base = map - addr_min;
388 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
389 if (ph->p_type != PT_LOAD) continue;
390 /* Check if the programs headers are in this load segment, and
391 * if so, record the address for use by dl_iterate_phdr. */
392 if (!dso->phdr && eh->e_phoff >= ph->p_offset
393 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
394 dso->phdr = (void *)(base + ph->p_vaddr
395 + (eh->e_phoff-ph->p_offset));
396 dso->phnum = eh->e_phnum;
398 /* Reuse the existing mapping for the lowest-address LOAD */
399 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
400 this_min = ph->p_vaddr & -PAGE_SIZE;
401 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
402 off_start = ph->p_offset & -PAGE_SIZE;
403 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
404 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
405 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
406 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
408 if (ph->p_memsz > ph->p_filesz) {
409 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
410 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
411 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
412 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)
416 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
417 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
418 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
422 if (!runtime) reclaim_gaps(base, ph0, eh->e_phentsize, eh->e_phnum);
424 dso->map_len = map_len;
426 dso->dynv = (void *)(base+dyn);
427 if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
433 if (map!=MAP_FAILED) munmap(map, map_len);
438 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
443 s += strspn(s, ":\n");
444 l = strcspn(s, ":\n");
445 if (l-1 >= INT_MAX) return -1;
446 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
448 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
453 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
456 const char *s, *t, *origin;
458 if (p->rpath) return 0;
459 if (!p->rpath_orig) return -1;
460 if (!strchr(p->rpath_orig, '$')) {
461 p->rpath = p->rpath_orig;
466 while ((t=strchr(s, '$'))) {
467 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
472 if (n > SSIZE_MAX/PATH_MAX) return -1;
474 if (p->kernel_mapped) {
475 /* $ORIGIN searches cannot be performed for the main program
476 * when it is suid/sgid/AT_SECURE. This is because the
477 * pathname is under the control of the caller of execve.
478 * For libraries, however, $ORIGIN can be processed safely
479 * since the library's pathname came from a trusted source
480 * (either system paths or a call to dlopen). */
483 l = readlink("/proc/self/exe", buf, buf_size);
491 t = strrchr(origin, '/');
492 l = t ? t-origin : 0;
493 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
494 if (!p->rpath) return -1;
498 while ((t=strchr(s, '$'))) {
501 memcpy(d, origin, l);
503 /* It was determined previously that the '$' is followed
504 * either by "ORIGIN" or "{ORIGIN}". */
505 s = t + 7 + 2*(t[1]=='{');
511 static void decode_dyn(struct dso *p)
513 size_t dyn[DYN_CNT] = {0};
514 decode_vec(p->dynv, dyn, DYN_CNT);
515 p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
516 p->strings = (void *)(p->base + dyn[DT_STRTAB]);
517 if (dyn[0]&(1<<DT_HASH))
518 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
519 if (dyn[0]&(1<<DT_RPATH))
520 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
521 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
522 p->ghashtab = (void *)(p->base + *dyn);
523 if (search_vec(p->dynv, dyn, DT_VERSYM))
524 p->versym = (void *)(p->base + *dyn);
527 static struct dso *load_library(const char *name, struct dso *needed_by)
529 char buf[2*NAME_MAX+2];
530 const char *pathname;
532 struct dso *p, temp_dso = {0};
539 /* Catch and block attempts to reload the implementation itself */
540 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
541 static const char *rp, reserved[] =
542 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
543 char *z = strchr(name, '.');
546 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
549 /* Track which names have been resolved
550 * and only report each one once. */
551 static unsigned reported;
552 unsigned mask = 1U<<(rp-reserved);
553 if (!(reported & mask)) {
555 dprintf(1, "\t%s => %s (%p)\n",
564 if (!strcmp(name, ldso->name)) is_self = 1;
569 tail = ldso->next ? ldso->next : ldso;
573 if (strchr(name, '/')) {
575 fd = open(name, O_RDONLY|O_CLOEXEC);
577 /* Search for the name to see if it's already loaded */
578 for (p=head->next; p; p=p->next) {
579 if (p->shortname && !strcmp(p->shortname, name)) {
584 if (strlen(name) > NAME_MAX) return 0;
586 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
587 for (p=needed_by; fd < 0 && p; p=p->needed_by)
588 if (!fixup_rpath(p, buf, sizeof buf))
589 fd = path_open(name, p->rpath, buf, sizeof buf);
594 if (ldso->name[0]=='/') {
596 for (s=t=z=ldso->name; *s; s++)
597 if (*s=='/') z=t, t=s;
598 prefix_len = z-ldso->name;
599 if (prefix_len < PATH_MAX)
606 char etc_ldso_path[prefix_len + 1
607 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
608 snprintf(etc_ldso_path, sizeof etc_ldso_path,
609 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
610 (int)prefix_len, prefix);
611 FILE *f = fopen(etc_ldso_path, "rbe");
613 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
618 } else if (errno != ENOENT) {
622 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
623 fd = path_open(name, sys_path, buf, sizeof buf);
627 if (fd < 0) return 0;
628 if (fstat(fd, &st) < 0) {
632 for (p=head->next; p; p=p->next) {
633 if (p->dev == st.st_dev && p->ino == st.st_ino) {
634 /* If this library was previously loaded with a
635 * pathname but a search found the same inode,
636 * setup its shortname so it can be found by name. */
637 if (!p->shortname && pathname != name)
638 p->shortname = strrchr(p->name, '/')+1;
644 map = noload ? 0 : map_library(fd, &temp_dso);
648 /* Allocate storage for the new DSO. When there is TLS, this
649 * storage must include a reservation for all pre-existing
650 * threads to obtain copies of both the new TLS, and an
651 * extended DTV capable of storing an additional slot for
652 * the newly-loaded DSO. */
653 alloc_size = sizeof *p + strlen(pathname) + 1;
654 if (runtime && temp_dso.tls_image) {
655 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
656 + sizeof(void *) * (tls_cnt+3);
657 n_th = libc.threads_minus_1 + 1;
658 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
659 else alloc_size += n_th * per_th;
661 p = calloc(1, alloc_size);
663 munmap(map, temp_dso.map_len);
666 memcpy(p, &temp_dso, sizeof temp_dso);
671 p->needed_by = needed_by;
673 strcpy(p->name, pathname);
674 /* Add a shortname only if name arg was not an explicit pathname. */
675 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
677 if (runtime && !libc.has_thread_pointer) {
678 munmap(map, p->map_len);
683 p->tls_id = ++tls_cnt;
684 tls_align = MAXP2(tls_align, p->tls_align);
686 p->tls_offset = tls_offset + ( (tls_align-1) &
687 -(tls_offset + (uintptr_t)p->tls_image) );
688 tls_offset += p->tls_size;
690 tls_offset += p->tls_size + p->tls_align - 1;
691 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
693 p->tls_offset = tls_offset;
695 p->new_dtv = (void *)(-sizeof(size_t) &
696 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
697 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
704 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
709 static void load_deps(struct dso *p)
712 struct dso ***deps = &p->deps, **tmp, *dep;
713 for (; p; p=p->next) {
714 for (i=0; p->dynv[i]; i+=2) {
715 if (p->dynv[i] != DT_NEEDED) continue;
716 dep = load_library(p->strings + p->dynv[i+1], p);
718 snprintf(errbuf, sizeof errbuf,
719 "Error loading shared library %s: %m (needed by %s)",
720 p->strings + p->dynv[i+1], p->name);
721 if (runtime) longjmp(*rtld_fail, 1);
722 dprintf(2, "%s\n", errbuf);
727 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
728 if (!tmp) longjmp(*rtld_fail, 1);
737 static void load_preload(char *s)
742 for ( ; *s && isspace(*s); s++);
743 for (z=s; *z && !isspace(*z); z++);
751 static void make_global(struct dso *p)
753 for (; p; p=p->next) p->global = 1;
756 static void reloc_all(struct dso *p)
758 size_t dyn[DYN_CNT] = {0};
759 for (; p; p=p->next) {
760 if (p->relocated) continue;
761 decode_vec(p->dynv, dyn, DYN_CNT);
762 #ifdef NEED_ARCH_RELOCS
763 do_arch_relocs(p, head);
765 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
766 2+(dyn[DT_PLTREL]==DT_RELA));
767 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
768 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
773 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
775 for (; cnt--; ph = (void *)((char *)ph + stride))
776 if (ph->p_type == PT_DYNAMIC)
781 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
783 size_t min_addr = -1, max_addr = 0;
784 for (; cnt--; ph = (void *)((char *)ph + stride)) {
785 if (ph->p_type != PT_LOAD) continue;
786 if (ph->p_vaddr < min_addr)
787 min_addr = ph->p_vaddr;
788 if (ph->p_vaddr+ph->p_memsz > max_addr)
789 max_addr = ph->p_vaddr+ph->p_memsz;
791 min_addr &= -PAGE_SIZE;
792 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
793 p->map = p->base + min_addr;
794 p->map_len = max_addr - min_addr;
797 static void do_fini()
800 size_t dyn[DYN_CNT] = {0};
801 for (p=fini_head; p; p=p->fini_next) {
802 if (!p->constructed) continue;
803 decode_vec(p->dynv, dyn, DYN_CNT);
804 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
805 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
806 size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
807 while (n--) ((void (*)(void))*--fn)();
809 #ifndef NO_LEGACY_INITFINI
810 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
811 ((void (*)(void))(p->base + dyn[DT_FINI]))();
816 static void do_init_fini(struct dso *p)
818 size_t dyn[DYN_CNT] = {0};
819 int need_locking = libc.threads_minus_1;
820 /* Allow recursive calls that arise when a library calls
821 * dlopen from one of its constructors, but block any
822 * other threads until all ctors have finished. */
823 if (need_locking) pthread_mutex_lock(&init_fini_lock);
824 for (; p; p=p->prev) {
825 if (p->constructed) continue;
827 decode_vec(p->dynv, dyn, DYN_CNT);
828 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
829 p->fini_next = fini_head;
832 #ifndef NO_LEGACY_INITFINI
833 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
834 ((void (*)(void))(p->base + dyn[DT_INIT]))();
836 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
837 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
838 size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
839 while (n--) ((void (*)(void))*fn++)();
841 if (!need_locking && libc.threads_minus_1) {
843 pthread_mutex_lock(&init_fini_lock);
846 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
849 void _dl_debug_state(void)
855 pthread_t self = __pthread_self();
857 for (p=head; p; p=p->next) {
858 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
859 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
860 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
861 p->tls_size - p->tls_len);
862 if (p->tls_id == (size_t)self->dtv[0]) break;
866 void *__copy_tls(unsigned char *mem)
871 void **dtv = (void *)mem;
872 dtv[0] = (void *)tls_cnt;
874 td = (void *)(dtv+1);
880 mem += sizeof(void *) * (tls_cnt+1);
881 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
883 mem += sizeof(struct pthread);
885 for (p=head; p; p=p->next) {
886 if (!p->tls_id) continue;
887 dtv[p->tls_id] = mem + p->tls_offset;
888 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
891 mem += libc.tls_size - sizeof(struct pthread);
892 mem -= (uintptr_t)mem & (tls_align-1);
895 for (p=head; p; p=p->next) {
896 if (!p->tls_id) continue;
897 dtv[p->tls_id] = mem - p->tls_offset;
898 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
905 void *__tls_get_addr(size_t *v)
907 pthread_t self = __pthread_self();
908 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
909 return (char *)self->dtv[v[0]]+v[1];
911 /* Block signals to make accessing new TLS async-signal-safe */
913 pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
914 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
915 pthread_sigmask(SIG_SETMASK, &set, 0);
916 return (char *)self->dtv[v[0]]+v[1];
919 /* This is safe without any locks held because, if the caller
920 * is able to request the Nth entry of the DTV, the DSO list
921 * must be valid at least that far out and it was synchronized
922 * at program startup or by an already-completed call to dlopen. */
924 for (p=head; p->tls_id != v[0]; p=p->next);
926 /* Get new DTV space from new DSO if needed */
927 if (v[0] > (size_t)self->dtv[0]) {
928 void **newdtv = p->new_dtv +
929 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
930 memcpy(newdtv, self->dtv,
931 ((size_t)self->dtv[0]+1) * sizeof(void *));
932 newdtv[0] = (void *)v[0];
936 /* Get new TLS memory from new DSO */
937 unsigned char *mem = p->new_tls +
938 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
939 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
940 self->dtv[v[0]] = mem;
941 memcpy(mem, p->tls_image, p->tls_len);
942 pthread_sigmask(SIG_SETMASK, &set, 0);
946 static void update_tls_size()
948 libc.tls_size = ALIGN(
949 (1+tls_cnt) * sizeof(void *) +
951 sizeof(struct pthread) +
956 void *__dynlink(int argc, char **argv)
958 size_t aux[AUX_CNT] = {0};
962 static struct dso builtin_dsos[3];
963 struct dso *const app = builtin_dsos+0;
964 struct dso *const lib = builtin_dsos+1;
965 struct dso *const vdso = builtin_dsos+2;
969 char **envp = argv+argc+1;
972 /* Find aux vector just past environ[] */
973 for (i=argc+1; argv[i]; i++)
974 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
975 env_path = argv[i]+16;
976 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
977 env_preload = argv[i]+11;
978 auxv = (void *)(argv+i+1);
980 decode_vec(auxv, aux, AUX_CNT);
982 /* Only trust user/env if kernel says we're not suid/sgid */
983 if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
984 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
989 libc.page_size = aux[AT_PAGESZ];
991 /* If the dynamic linker was invoked as a program itself, AT_BASE
992 * will not be set. In that case, we assume the base address is
993 * the start of the page containing the PHDRs; I don't know any
994 * better approach... */
996 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
997 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
1000 /* The dynamic linker load address is passed by the kernel
1001 * in the AUX vector, so this is easy. */
1002 lib->base = (void *)aux[AT_BASE];
1003 lib->name = lib->shortname = "libc.so";
1005 lib->kernel_mapped = 1;
1006 ehdr = (void *)lib->base;
1007 lib->phnum = ehdr->e_phnum;
1008 lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1009 find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
1010 lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
1011 ehdr->e_phnum, ehdr->e_phentsize));
1015 size_t interp_off = 0;
1016 size_t tls_image = 0;
1017 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1018 app->phdr = phdr = (void *)aux[AT_PHDR];
1019 app->phnum = aux[AT_PHNUM];
1020 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1021 if (phdr->p_type == PT_PHDR)
1022 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1023 else if (phdr->p_type == PT_INTERP)
1024 interp_off = (size_t)phdr->p_vaddr;
1025 else if (phdr->p_type == PT_TLS) {
1026 tls_image = phdr->p_vaddr;
1027 app->tls_len = phdr->p_filesz;
1028 app->tls_size = phdr->p_memsz;
1029 app->tls_align = phdr->p_align;
1032 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1033 if (interp_off) lib->name = (char *)app->base + interp_off;
1034 if ((aux[0] & (1UL<<AT_EXECFN))
1035 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1036 app->name = (char *)aux[AT_EXECFN];
1038 app->name = argv[0];
1039 app->kernel_mapped = 1;
1040 app->dynv = (void *)(app->base + find_dyn(
1041 (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
1042 find_map_range((void *)aux[AT_PHDR],
1043 aux[AT_PHNUM], aux[AT_PHENT], app);
1046 char *ldname = argv[0];
1047 size_t l = strlen(ldname);
1048 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1049 *argv++ = (void *)-1;
1050 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
1052 dprintf(2, "musl libc\n"
1054 "Dynamic Program Loader\n"
1055 "Usage: %s [--] pathname%s\n",
1056 __libc_get_version(), ldname,
1057 ldd_mode ? "" : " [args]");
1060 fd = open(argv[0], O_RDONLY);
1062 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1066 ehdr = (void *)map_library(fd, app);
1068 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1074 app->name = argv[0];
1075 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1076 /* Find the name that would have been used for the dynamic
1077 * linker had ldd not taken its place. */
1079 for (i=0; i<app->phnum; i++) {
1080 if (app->phdr[i].p_type == PT_INTERP)
1081 lib->name = (void *)(app->base
1082 + app->phdr[i].p_vaddr);
1084 dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1087 if (app->tls_size) {
1088 app->tls_id = tls_cnt = 1;
1090 app->tls_offset = 0;
1091 tls_offset = app->tls_size
1092 + ( -((uintptr_t)app->tls_image + app->tls_size)
1093 & (app->tls_align-1) );
1095 tls_offset = app->tls_offset = app->tls_size
1096 + ( -((uintptr_t)app->tls_image + app->tls_size)
1097 & (app->tls_align-1) );
1099 tls_align = MAXP2(tls_align, app->tls_align);
1104 /* Attach to vdso, if provided by the kernel */
1105 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1106 ehdr = (void *)vdso_base;
1107 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1108 vdso->phnum = ehdr->e_phnum;
1109 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1110 if (phdr->p_type == PT_DYNAMIC)
1111 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1112 if (phdr->p_type == PT_LOAD)
1113 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1116 vdso->shortname = "linux-gate.so.1";
1123 /* Initial dso chain consists only of the app. We temporarily
1124 * append the dynamic linker/libc so we can relocate it, then
1125 * restore the initial chain in preparation for loading third
1126 * party libraries (preload/needed). */
1133 /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1135 /* Donate unused parts of app and library mapping to malloc */
1136 reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
1137 ehdr = (void *)lib->base;
1138 reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
1139 ehdr->e_phentsize, ehdr->e_phnum);
1141 /* Load preload/needed libraries, add their symbols to the global
1142 * namespace, and perform all remaining relocations. The main
1143 * program must be relocated LAST since it may contain copy
1144 * relocations which depend on libraries' relocations. */
1145 if (env_preload) load_preload(env_preload);
1149 reloc_all(app->next);
1153 if (libc.tls_size > sizeof builtin_tls) {
1154 initial_tls = calloc(libc.tls_size, 1);
1156 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1157 argv[0], libc.tls_size);
1161 initial_tls = builtin_tls;
1163 if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
1164 dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
1168 if (ldso_fail) _exit(127);
1169 if (ldd_mode) _exit(0);
1171 /* Switch to runtime mode: any further failures in the dynamic
1172 * linker are a reportable failure rather than a fatal startup
1173 * error. If the dynamic loader (dlopen) will not be used, free
1174 * all memory used by the dynamic linker. */
1177 #ifndef DYNAMIC_IS_RO
1178 for (i=0; app->dynv[i]; i+=2)
1179 if (app->dynv[i]==DT_DEBUG)
1180 app->dynv[i+1] = (size_t)&debug;
1183 debug.bp = _dl_debug_state;
1185 debug.base = lib->base;
1189 if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1190 __init_libc(envp, argv[0]);
1195 return (void *)aux[AT_ENTRY];
1198 void *dlopen(const char *file, int mode)
1200 struct dso *volatile p, *orig_tail, *next;
1201 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1206 if (!file) return head;
1208 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1209 pthread_rwlock_wrlock(&lock);
1213 orig_tls_cnt = tls_cnt;
1214 orig_tls_offset = tls_offset;
1215 orig_tls_align = tls_align;
1217 noload = mode & RTLD_NOLOAD;
1220 if (setjmp(*rtld_fail)) {
1221 /* Clean up anything new that was (partially) loaded */
1222 if (p && p->deps) for (i=0; p->deps[i]; i++)
1223 if (p->deps[i]->global < 0)
1224 p->deps[i]->global = 0;
1225 for (p=orig_tail->next; p; p=next) {
1227 munmap(p->map, p->map_len);
1231 tls_cnt = orig_tls_cnt;
1232 tls_offset = orig_tls_offset;
1233 tls_align = orig_tls_align;
1239 } else p = load_library(file, head);
1242 snprintf(errbuf, sizeof errbuf, noload ?
1243 "Library %s is not already loaded" :
1244 "Error loading shared library %s: %m",
1250 /* First load handling */
1253 if (p->deps) for (i=0; p->deps[i]; i++)
1254 if (!p->deps[i]->global)
1255 p->deps[i]->global = -1;
1256 if (!p->global) p->global = -1;
1258 if (p->deps) for (i=0; p->deps[i]; i++)
1259 if (p->deps[i]->global < 0)
1260 p->deps[i]->global = 0;
1261 if (p->global < 0) p->global = 0;
1264 if (mode & RTLD_GLOBAL) {
1265 if (p->deps) for (i=0; p->deps[i]; i++)
1266 p->deps[i]->global = 1;
1272 if (ssp_used) __init_ssp(libc.auxv);
1279 pthread_rwlock_unlock(&lock);
1280 if (p) do_init_fini(orig_tail);
1281 pthread_setcancelstate(cs, 0);
1285 static int invalid_dso_handle(void *h)
1288 for (p=head; p; p=p->next) if (h==p) return 0;
1289 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1294 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1297 uint32_t h = 0, gh = 0;
1299 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1300 if (p == RTLD_DEFAULT) {
1302 } else if (p == RTLD_NEXT) {
1303 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1307 struct symdef def = find_sym(p, s, 0);
1308 if (!def.sym) goto failed;
1309 if ((def.sym->st_info&0xf) == STT_TLS)
1310 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1311 return def.dso->base + def.sym->st_value;
1313 if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1317 sym = gnu_lookup(s, gh, p);
1320 sym = sysv_lookup(s, h, p);
1322 if (sym && (sym->st_info&0xf) == STT_TLS)
1323 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1324 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1325 return p->base + sym->st_value;
1326 if (p->deps) for (i=0; p->deps[i]; i++) {
1327 if (p->deps[i]->ghashtab) {
1328 if (!gh) gh = gnu_hash(s);
1329 sym = gnu_lookup(s, gh, p->deps[i]);
1331 if (!h) h = sysv_hash(s);
1332 sym = sysv_lookup(s, h, p->deps[i]);
1334 if (sym && (sym->st_info&0xf) == STT_TLS)
1335 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1336 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1337 return p->deps[i]->base + sym->st_value;
1341 snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1345 int __dladdr(const void *addr, Dl_info *info)
1355 pthread_rwlock_rdlock(&lock);
1356 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1357 pthread_rwlock_unlock(&lock);
1362 strings = p->strings;
1364 nsym = p->hashtab[1];
1368 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1369 sym += p->ghashtab[1];
1370 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1371 if (buckets[i] > nsym)
1375 nsym -= p->ghashtab[1];
1376 hashval = buckets + p->ghashtab[0] + nsym;
1378 while (!(*hashval++ & 1));
1382 for (; nsym; nsym--, sym++) {
1384 && (1<<(sym->st_info&0xf) & OK_TYPES)
1385 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1386 void *symaddr = p->base + sym->st_value;
1387 if (symaddr > addr || symaddr < best)
1390 bestname = strings + sym->st_name;
1391 if (addr == symaddr)
1396 if (!best) return 0;
1398 info->dli_fname = p->name;
1399 info->dli_fbase = p->base;
1400 info->dli_sname = bestname;
1401 info->dli_saddr = best;
1406 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1409 pthread_rwlock_rdlock(&lock);
1410 res = do_dlsym(p, s, ra);
1411 pthread_rwlock_unlock(&lock);
1415 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1417 struct dso *current;
1418 struct dl_phdr_info info;
1420 for(current = head; current;) {
1421 info.dlpi_addr = (uintptr_t)current->base;
1422 info.dlpi_name = current->name;
1423 info.dlpi_phdr = current->phdr;
1424 info.dlpi_phnum = current->phnum;
1425 info.dlpi_adds = gencnt;
1427 info.dlpi_tls_modid = current->tls_id;
1428 info.dlpi_tls_data = current->tls_image;
1430 ret = (callback)(&info, sizeof (info), data);
1432 if (ret != 0) break;
1434 pthread_rwlock_rdlock(&lock);
1435 current = current->next;
1436 pthread_rwlock_unlock(&lock);
1441 static int invalid_dso_handle(void *h)
1443 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1447 void *dlopen(const char *file, int mode)
1451 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1455 int __dladdr (const void *addr, Dl_info *info)
1461 int __dlinfo(void *dso, int req, void *res)
1463 if (invalid_dso_handle(dso)) return -1;
1464 if (req != RTLD_DI_LINKMAP) {
1465 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1469 *(struct link_map **)res = dso;
1475 if (!errflag) return 0;
1480 int dlclose(void *p)
1482 return invalid_dso_handle(p);