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;
74 struct dso **deps, *needed_by;
75 char *rpath_orig, *rpath;
77 size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
78 size_t relro_start, relro_end;
80 unsigned char *new_tls;
81 int new_dtv_idx, new_tls_idx;
82 struct dso *fini_next;
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;
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};
202 for (; dso; dso=dso->next) {
204 if (!dso->global) continue;
206 if (!gh) gh = gnu_hash(s);
207 sym = gnu_lookup(s, gh, dso);
209 if (!h) h = sysv_hash(s);
210 sym = sysv_lookup(s, h, dso);
214 if (need_def || (sym->st_info&0xf) == STT_TLS)
217 if ((sym->st_info&0xf) != STT_TLS)
219 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
220 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
222 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
225 if (sym->st_info>>4 == STB_GLOBAL) break;
230 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
232 unsigned char *base = dso->base;
233 Sym *syms = dso->syms;
234 char *strings = dso->strings;
242 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
243 type = R_TYPE(rel[1]);
244 sym_index = R_SYM(rel[1]);
246 sym = syms + sym_index;
247 name = strings + sym->st_name;
248 ctx = IS_COPY(type) ? head->next : head;
249 def = find_sym(ctx, name, IS_PLT(type));
250 if (!def.sym && (sym->st_shndx != SHN_UNDEF
251 || sym->st_info>>4 != STB_WEAK)) {
252 snprintf(errbuf, sizeof errbuf,
253 "Error relocating %s: %s: symbol not found",
255 if (runtime) longjmp(*rtld_fail, 1);
256 dprintf(2, "%s\n", errbuf);
265 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
266 stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
267 def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
271 /* A huge hack: to make up for the wastefulness of shared libraries
272 * needing at least a page of dirty memory even if they have no global
273 * data, we reclaim the gaps at the beginning and end of writable maps
274 * and "donate" them to the heap by setting up minimal malloc
275 * structures and then freeing them. */
277 static void reclaim(struct dso *dso, size_t start, size_t end)
280 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
281 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
282 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
283 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
284 if (start>end || end-start < 4*sizeof(size_t)) return;
285 a = (size_t *)(dso->base + start);
286 z = (size_t *)(dso->base + end);
288 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
293 static void reclaim_gaps(struct dso *dso)
295 Phdr *ph = dso->phdr;
296 size_t phcnt = dso->phnum;
298 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
299 if (ph->p_type!=PT_LOAD) continue;
300 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
301 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
302 reclaim(dso, ph->p_vaddr+ph->p_memsz,
303 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
307 static void *map_library(int fd, struct dso *dso)
309 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
310 void *allocated_buf=0;
312 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
313 size_t this_min, this_max;
318 unsigned char *map=MAP_FAILED, *base;
323 ssize_t l = read(fd, buf, sizeof buf);
326 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
328 phsize = eh->e_phentsize * eh->e_phnum;
329 if (phsize > sizeof buf - sizeof *eh) {
330 allocated_buf = malloc(phsize);
331 if (!allocated_buf) return 0;
332 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
333 if (l < 0) goto error;
334 if (l != phsize) goto noexec;
335 ph = ph0 = allocated_buf;
336 } else if (eh->e_phoff + phsize > l) {
337 l = pread(fd, buf+1, phsize, eh->e_phoff);
338 if (l < 0) goto error;
339 if (l != phsize) goto noexec;
340 ph = ph0 = (void *)(buf + 1);
342 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
344 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
345 if (ph->p_type == PT_DYNAMIC) {
347 } else if (ph->p_type == PT_TLS) {
348 tls_image = ph->p_vaddr;
349 dso->tls_align = ph->p_align;
350 dso->tls_len = ph->p_filesz;
351 dso->tls_size = ph->p_memsz;
352 } else if (ph->p_type == PT_GNU_RELRO) {
353 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
354 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
356 if (ph->p_type != PT_LOAD) continue;
357 if (ph->p_vaddr < addr_min) {
358 addr_min = ph->p_vaddr;
359 off_start = ph->p_offset;
360 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
361 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
362 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
364 if (ph->p_vaddr+ph->p_memsz > addr_max) {
365 addr_max = ph->p_vaddr+ph->p_memsz;
368 if (!dyn) goto noexec;
369 addr_max += PAGE_SIZE-1;
370 addr_max &= -PAGE_SIZE;
371 addr_min &= -PAGE_SIZE;
372 off_start &= -PAGE_SIZE;
373 map_len = addr_max - addr_min + off_start;
374 /* The first time, we map too much, possibly even more than
375 * the length of the file. This is okay because we will not
376 * use the invalid part; we just need to reserve the right
377 * amount of virtual address space to map over later. */
378 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
379 if (map==MAP_FAILED) goto error;
380 /* If the loaded file is not relocatable and the requested address is
381 * not available, then the load operation must fail. */
382 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
386 base = map - addr_min;
389 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
390 if (ph->p_type != PT_LOAD) continue;
391 /* Check if the programs headers are in this load segment, and
392 * if so, record the address for use by dl_iterate_phdr. */
393 if (!dso->phdr && eh->e_phoff >= ph->p_offset
394 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
395 dso->phdr = (void *)(base + ph->p_vaddr
396 + (eh->e_phoff-ph->p_offset));
397 dso->phnum = eh->e_phnum;
398 dso->phentsize = eh->e_phentsize;
400 /* Reuse the existing mapping for the lowest-address LOAD */
401 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
402 this_min = ph->p_vaddr & -PAGE_SIZE;
403 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
404 off_start = ph->p_offset & -PAGE_SIZE;
405 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
406 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
407 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
408 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
410 if (ph->p_memsz > ph->p_filesz) {
411 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
412 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
413 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
414 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)
418 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
419 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
420 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
425 dso->map_len = map_len;
427 dso->dynv = (void *)(base+dyn);
428 if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
429 if (!runtime) reclaim_gaps(dso);
435 if (map!=MAP_FAILED) munmap(map, map_len);
440 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
445 s += strspn(s, ":\n");
446 l = strcspn(s, ":\n");
447 if (l-1 >= INT_MAX) return -1;
448 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
450 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
455 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
458 const char *s, *t, *origin;
460 if (p->rpath) return 0;
461 if (!p->rpath_orig) return -1;
462 if (!strchr(p->rpath_orig, '$')) {
463 p->rpath = p->rpath_orig;
468 while ((t=strchr(s, '$'))) {
469 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
474 if (n > SSIZE_MAX/PATH_MAX) return -1;
476 if (p->kernel_mapped) {
477 /* $ORIGIN searches cannot be performed for the main program
478 * when it is suid/sgid/AT_SECURE. This is because the
479 * pathname is under the control of the caller of execve.
480 * For libraries, however, $ORIGIN can be processed safely
481 * since the library's pathname came from a trusted source
482 * (either system paths or a call to dlopen). */
485 l = readlink("/proc/self/exe", buf, buf_size);
493 t = strrchr(origin, '/');
494 l = t ? t-origin : 0;
495 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
496 if (!p->rpath) return -1;
500 while ((t=strchr(s, '$'))) {
503 memcpy(d, origin, l);
505 /* It was determined previously that the '$' is followed
506 * either by "ORIGIN" or "{ORIGIN}". */
507 s = t + 7 + 2*(t[1]=='{');
513 static void decode_dyn(struct dso *p)
515 size_t dyn[DYN_CNT] = {0};
516 decode_vec(p->dynv, dyn, DYN_CNT);
517 p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
518 p->strings = (void *)(p->base + dyn[DT_STRTAB]);
519 if (dyn[0]&(1<<DT_HASH))
520 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
521 if (dyn[0]&(1<<DT_RPATH))
522 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
523 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
524 p->ghashtab = (void *)(p->base + *dyn);
525 if (search_vec(p->dynv, dyn, DT_VERSYM))
526 p->versym = (void *)(p->base + *dyn);
529 static struct dso *load_library(const char *name, struct dso *needed_by)
531 char buf[2*NAME_MAX+2];
532 const char *pathname;
534 struct dso *p, temp_dso = {0};
541 /* Catch and block attempts to reload the implementation itself */
542 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
543 static const char *rp, reserved[] =
544 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
545 char *z = strchr(name, '.');
548 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
551 /* Track which names have been resolved
552 * and only report each one once. */
553 static unsigned reported;
554 unsigned mask = 1U<<(rp-reserved);
555 if (!(reported & mask)) {
557 dprintf(1, "\t%s => %s (%p)\n",
566 if (!strcmp(name, ldso->name)) is_self = 1;
571 tail = ldso->next ? ldso->next : ldso;
575 if (strchr(name, '/')) {
577 fd = open(name, O_RDONLY|O_CLOEXEC);
579 /* Search for the name to see if it's already loaded */
580 for (p=head->next; p; p=p->next) {
581 if (p->shortname && !strcmp(p->shortname, name)) {
586 if (strlen(name) > NAME_MAX) return 0;
588 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
589 for (p=needed_by; fd < 0 && p; p=p->needed_by)
590 if (!fixup_rpath(p, buf, sizeof buf))
591 fd = path_open(name, p->rpath, buf, sizeof buf);
596 if (ldso->name[0]=='/') {
598 for (s=t=z=ldso->name; *s; s++)
599 if (*s=='/') z=t, t=s;
600 prefix_len = z-ldso->name;
601 if (prefix_len < PATH_MAX)
608 char etc_ldso_path[prefix_len + 1
609 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
610 snprintf(etc_ldso_path, sizeof etc_ldso_path,
611 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
612 (int)prefix_len, prefix);
613 FILE *f = fopen(etc_ldso_path, "rbe");
615 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
620 } else if (errno != ENOENT) {
624 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
625 fd = path_open(name, sys_path, buf, sizeof buf);
629 if (fd < 0) return 0;
630 if (fstat(fd, &st) < 0) {
634 for (p=head->next; p; p=p->next) {
635 if (p->dev == st.st_dev && p->ino == st.st_ino) {
636 /* If this library was previously loaded with a
637 * pathname but a search found the same inode,
638 * setup its shortname so it can be found by name. */
639 if (!p->shortname && pathname != name)
640 p->shortname = strrchr(p->name, '/')+1;
646 map = noload ? 0 : map_library(fd, &temp_dso);
650 /* Allocate storage for the new DSO. When there is TLS, this
651 * storage must include a reservation for all pre-existing
652 * threads to obtain copies of both the new TLS, and an
653 * extended DTV capable of storing an additional slot for
654 * the newly-loaded DSO. */
655 alloc_size = sizeof *p + strlen(pathname) + 1;
656 if (runtime && temp_dso.tls_image) {
657 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
658 + sizeof(void *) * (tls_cnt+3);
659 n_th = libc.threads_minus_1 + 1;
660 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
661 else alloc_size += n_th * per_th;
663 p = calloc(1, alloc_size);
665 munmap(map, temp_dso.map_len);
668 memcpy(p, &temp_dso, sizeof temp_dso);
673 p->needed_by = needed_by;
675 strcpy(p->name, pathname);
676 /* Add a shortname only if name arg was not an explicit pathname. */
677 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
679 if (runtime && !libc.has_thread_pointer) {
680 munmap(map, p->map_len);
685 p->tls_id = ++tls_cnt;
686 tls_align = MAXP2(tls_align, p->tls_align);
688 p->tls_offset = tls_offset + ( (tls_align-1) &
689 -(tls_offset + (uintptr_t)p->tls_image) );
690 tls_offset += p->tls_size;
692 tls_offset += p->tls_size + p->tls_align - 1;
693 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
695 p->tls_offset = tls_offset;
697 p->new_dtv = (void *)(-sizeof(size_t) &
698 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
699 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
706 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
711 static void load_deps(struct dso *p)
714 struct dso ***deps = &p->deps, **tmp, *dep;
715 for (; p; p=p->next) {
716 for (i=0; p->dynv[i]; i+=2) {
717 if (p->dynv[i] != DT_NEEDED) continue;
718 dep = load_library(p->strings + p->dynv[i+1], p);
720 snprintf(errbuf, sizeof errbuf,
721 "Error loading shared library %s: %m (needed by %s)",
722 p->strings + p->dynv[i+1], p->name);
723 if (runtime) longjmp(*rtld_fail, 1);
724 dprintf(2, "%s\n", errbuf);
729 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
730 if (!tmp) longjmp(*rtld_fail, 1);
739 static void load_preload(char *s)
744 for ( ; *s && isspace(*s); s++);
745 for (z=s; *z && !isspace(*z); z++);
753 static void make_global(struct dso *p)
755 for (; p; p=p->next) p->global = 1;
758 static void reloc_all(struct dso *p)
760 size_t dyn[DYN_CNT] = {0};
761 for (; p; p=p->next) {
762 if (p->relocated) continue;
763 decode_vec(p->dynv, dyn, DYN_CNT);
764 #ifdef NEED_ARCH_RELOCS
765 do_arch_relocs(p, head);
767 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
768 2+(dyn[DT_PLTREL]==DT_RELA));
769 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
770 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
772 if (p->relro_start != p->relro_end &&
773 mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) {
774 snprintf(errbuf, sizeof errbuf,
775 "Error relocating %s: RELRO protection failed: %m",
777 if (runtime) longjmp(*rtld_fail, 1);
778 dprintf(2, "%s\n", errbuf);
786 static void kernel_mapped_dso(struct dso *p)
788 size_t min_addr = -1, max_addr = 0, cnt;
790 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
791 if (ph->p_type == PT_DYNAMIC) {
792 p->dynv = (void *)(p->base + ph->p_vaddr);
793 } else if (ph->p_type == PT_GNU_RELRO) {
794 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
795 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
797 if (ph->p_type != PT_LOAD) continue;
798 if (ph->p_vaddr < min_addr)
799 min_addr = ph->p_vaddr;
800 if (ph->p_vaddr+ph->p_memsz > max_addr)
801 max_addr = ph->p_vaddr+ph->p_memsz;
803 min_addr &= -PAGE_SIZE;
804 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
805 p->map = p->base + min_addr;
806 p->map_len = max_addr - min_addr;
807 p->kernel_mapped = 1;
810 static void do_fini()
813 size_t dyn[DYN_CNT] = {0};
814 for (p=fini_head; p; p=p->fini_next) {
815 if (!p->constructed) continue;
816 decode_vec(p->dynv, dyn, DYN_CNT);
817 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
818 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
819 size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
820 while (n--) ((void (*)(void))*--fn)();
822 #ifndef NO_LEGACY_INITFINI
823 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
824 ((void (*)(void))(p->base + dyn[DT_FINI]))();
829 static void do_init_fini(struct dso *p)
831 size_t dyn[DYN_CNT] = {0};
832 int need_locking = libc.threads_minus_1;
833 /* Allow recursive calls that arise when a library calls
834 * dlopen from one of its constructors, but block any
835 * other threads until all ctors have finished. */
836 if (need_locking) pthread_mutex_lock(&init_fini_lock);
837 for (; p; p=p->prev) {
838 if (p->constructed) continue;
840 decode_vec(p->dynv, dyn, DYN_CNT);
841 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
842 p->fini_next = fini_head;
845 #ifndef NO_LEGACY_INITFINI
846 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
847 ((void (*)(void))(p->base + dyn[DT_INIT]))();
849 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
850 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
851 size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
852 while (n--) ((void (*)(void))*fn++)();
854 if (!need_locking && libc.threads_minus_1) {
856 pthread_mutex_lock(&init_fini_lock);
859 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
862 void _dl_debug_state(void)
868 pthread_t self = __pthread_self();
870 for (p=head; p; p=p->next) {
871 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
872 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
873 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
874 p->tls_size - p->tls_len);
875 if (p->tls_id == (size_t)self->dtv[0]) break;
879 void *__copy_tls(unsigned char *mem)
884 void **dtv = (void *)mem;
885 dtv[0] = (void *)tls_cnt;
887 td = (void *)(dtv+1);
893 mem += sizeof(void *) * (tls_cnt+1);
894 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
896 mem += sizeof(struct pthread);
898 for (p=head; p; p=p->next) {
899 if (!p->tls_id) continue;
900 dtv[p->tls_id] = mem + p->tls_offset;
901 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
904 mem += libc.tls_size - sizeof(struct pthread);
905 mem -= (uintptr_t)mem & (tls_align-1);
908 for (p=head; p; p=p->next) {
909 if (!p->tls_id) continue;
910 dtv[p->tls_id] = mem - p->tls_offset;
911 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
918 void *__tls_get_addr(size_t *v)
920 pthread_t self = __pthread_self();
921 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
922 return (char *)self->dtv[v[0]]+v[1];
924 /* Block signals to make accessing new TLS async-signal-safe */
926 pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
927 if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
928 pthread_sigmask(SIG_SETMASK, &set, 0);
929 return (char *)self->dtv[v[0]]+v[1];
932 /* This is safe without any locks held because, if the caller
933 * is able to request the Nth entry of the DTV, the DSO list
934 * must be valid at least that far out and it was synchronized
935 * at program startup or by an already-completed call to dlopen. */
937 for (p=head; p->tls_id != v[0]; p=p->next);
939 /* Get new DTV space from new DSO if needed */
940 if (v[0] > (size_t)self->dtv[0]) {
941 void **newdtv = p->new_dtv +
942 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
943 memcpy(newdtv, self->dtv,
944 ((size_t)self->dtv[0]+1) * sizeof(void *));
945 newdtv[0] = (void *)v[0];
949 /* Get new TLS memory from new DSO */
950 unsigned char *mem = p->new_tls +
951 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
952 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
953 self->dtv[v[0]] = mem;
954 memcpy(mem, p->tls_image, p->tls_len);
955 pthread_sigmask(SIG_SETMASK, &set, 0);
959 static void update_tls_size()
961 libc.tls_size = ALIGN(
962 (1+tls_cnt) * sizeof(void *) +
964 sizeof(struct pthread) +
969 void *__dynlink(int argc, char **argv)
971 size_t aux[AUX_CNT] = {0};
975 static struct dso builtin_dsos[3];
976 struct dso *const app = builtin_dsos+0;
977 struct dso *const lib = builtin_dsos+1;
978 struct dso *const vdso = builtin_dsos+2;
982 char **envp = argv+argc+1;
985 /* Find aux vector just past environ[] */
986 for (i=argc+1; argv[i]; i++)
987 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
988 env_path = argv[i]+16;
989 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
990 env_preload = argv[i]+11;
991 auxv = (void *)(argv+i+1);
993 decode_vec(auxv, aux, AUX_CNT);
995 /* Only trust user/env if kernel says we're not suid/sgid */
996 if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
997 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
1002 libc.page_size = aux[AT_PAGESZ];
1004 /* If the dynamic linker was invoked as a program itself, AT_BASE
1005 * will not be set. In that case, we assume the base address is
1006 * the start of the page containing the PHDRs; I don't know any
1007 * better approach... */
1008 if (!aux[AT_BASE]) {
1009 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
1010 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
1013 /* The dynamic linker load address is passed by the kernel
1014 * in the AUX vector, so this is easy. */
1015 lib->base = (void *)aux[AT_BASE];
1016 lib->name = lib->shortname = "libc.so";
1018 ehdr = (void *)lib->base;
1019 lib->phnum = ehdr->e_phnum;
1020 lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1021 lib->phentsize = ehdr->e_phentsize;
1022 kernel_mapped_dso(lib);
1026 size_t interp_off = 0;
1027 size_t tls_image = 0;
1028 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1029 app->phdr = phdr = (void *)aux[AT_PHDR];
1030 app->phnum = aux[AT_PHNUM];
1031 app->phentsize = aux[AT_PHENT];
1032 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1033 if (phdr->p_type == PT_PHDR)
1034 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1035 else if (phdr->p_type == PT_INTERP)
1036 interp_off = (size_t)phdr->p_vaddr;
1037 else if (phdr->p_type == PT_TLS) {
1038 tls_image = phdr->p_vaddr;
1039 app->tls_len = phdr->p_filesz;
1040 app->tls_size = phdr->p_memsz;
1041 app->tls_align = phdr->p_align;
1044 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1045 if (interp_off) lib->name = (char *)app->base + interp_off;
1046 if ((aux[0] & (1UL<<AT_EXECFN))
1047 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1048 app->name = (char *)aux[AT_EXECFN];
1050 app->name = argv[0];
1051 kernel_mapped_dso(app);
1054 char *ldname = argv[0];
1055 size_t l = strlen(ldname);
1056 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1057 *argv++ = (void *)-1;
1058 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
1060 dprintf(2, "musl libc\n"
1062 "Dynamic Program Loader\n"
1063 "Usage: %s [--] pathname%s\n",
1064 __libc_get_version(), ldname,
1065 ldd_mode ? "" : " [args]");
1068 fd = open(argv[0], O_RDONLY);
1070 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1074 ehdr = (void *)map_library(fd, app);
1076 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1082 app->name = argv[0];
1083 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1084 /* Find the name that would have been used for the dynamic
1085 * linker had ldd not taken its place. */
1087 for (i=0; i<app->phnum; i++) {
1088 if (app->phdr[i].p_type == PT_INTERP)
1089 lib->name = (void *)(app->base
1090 + app->phdr[i].p_vaddr);
1092 dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1095 if (app->tls_size) {
1096 app->tls_id = tls_cnt = 1;
1098 app->tls_offset = 0;
1099 tls_offset = app->tls_size
1100 + ( -((uintptr_t)app->tls_image + app->tls_size)
1101 & (app->tls_align-1) );
1103 tls_offset = app->tls_offset = app->tls_size
1104 + ( -((uintptr_t)app->tls_image + app->tls_size)
1105 & (app->tls_align-1) );
1107 tls_align = MAXP2(tls_align, app->tls_align);
1112 /* Attach to vdso, if provided by the kernel */
1113 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1114 ehdr = (void *)vdso_base;
1115 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1116 vdso->phnum = ehdr->e_phnum;
1117 vdso->phentsize = ehdr->e_phentsize;
1118 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1119 if (phdr->p_type == PT_DYNAMIC)
1120 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1121 if (phdr->p_type == PT_LOAD)
1122 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1125 vdso->shortname = "linux-gate.so.1";
1132 /* Initial dso chain consists only of the app. We temporarily
1133 * append the dynamic linker/libc so we can relocate it, then
1134 * restore the initial chain in preparation for loading third
1135 * party libraries (preload/needed). */
1142 /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1144 /* Donate unused parts of app and library mapping to malloc */
1148 /* Load preload/needed libraries, add their symbols to the global
1149 * namespace, and perform all remaining relocations. The main
1150 * program must be relocated LAST since it may contain copy
1151 * relocations which depend on libraries' relocations. */
1152 if (env_preload) load_preload(env_preload);
1156 #ifndef DYNAMIC_IS_RO
1157 for (i=0; app->dynv[i]; i+=2)
1158 if (app->dynv[i]==DT_DEBUG)
1159 app->dynv[i+1] = (size_t)&debug;
1162 reloc_all(app->next);
1166 if (libc.tls_size > sizeof builtin_tls) {
1167 initial_tls = calloc(libc.tls_size, 1);
1169 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1170 argv[0], libc.tls_size);
1174 initial_tls = builtin_tls;
1176 if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
1177 dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
1181 if (ldso_fail) _exit(127);
1182 if (ldd_mode) _exit(0);
1184 /* Switch to runtime mode: any further failures in the dynamic
1185 * linker are a reportable failure rather than a fatal startup
1186 * error. If the dynamic loader (dlopen) will not be used, free
1187 * all memory used by the dynamic linker. */
1191 debug.bp = _dl_debug_state;
1193 debug.base = lib->base;
1197 __init_libc(envp, argv[0]);
1202 return (void *)aux[AT_ENTRY];
1205 void *dlopen(const char *file, int mode)
1207 struct dso *volatile p, *orig_tail, *next;
1208 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1213 if (!file) return head;
1215 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1216 pthread_rwlock_wrlock(&lock);
1220 orig_tls_cnt = tls_cnt;
1221 orig_tls_offset = tls_offset;
1222 orig_tls_align = tls_align;
1224 noload = mode & RTLD_NOLOAD;
1227 if (setjmp(*rtld_fail)) {
1228 /* Clean up anything new that was (partially) loaded */
1229 if (p && p->deps) for (i=0; p->deps[i]; i++)
1230 if (p->deps[i]->global < 0)
1231 p->deps[i]->global = 0;
1232 for (p=orig_tail->next; p; p=next) {
1234 munmap(p->map, p->map_len);
1238 tls_cnt = orig_tls_cnt;
1239 tls_offset = orig_tls_offset;
1240 tls_align = orig_tls_align;
1246 } else p = load_library(file, head);
1249 snprintf(errbuf, sizeof errbuf, noload ?
1250 "Library %s is not already loaded" :
1251 "Error loading shared library %s: %m",
1257 /* First load handling */
1260 if (p->deps) for (i=0; p->deps[i]; i++)
1261 if (!p->deps[i]->global)
1262 p->deps[i]->global = -1;
1263 if (!p->global) p->global = -1;
1265 if (p->deps) for (i=0; p->deps[i]; i++)
1266 if (p->deps[i]->global < 0)
1267 p->deps[i]->global = 0;
1268 if (p->global < 0) p->global = 0;
1271 if (mode & RTLD_GLOBAL) {
1272 if (p->deps) for (i=0; p->deps[i]; i++)
1273 p->deps[i]->global = 1;
1283 pthread_rwlock_unlock(&lock);
1284 if (p) do_init_fini(orig_tail);
1285 pthread_setcancelstate(cs, 0);
1289 static int invalid_dso_handle(void *h)
1292 for (p=head; p; p=p->next) if (h==p) return 0;
1293 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1298 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1301 uint32_t h = 0, gh = 0;
1303 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1304 if (p == RTLD_DEFAULT) {
1306 } else if (p == RTLD_NEXT) {
1307 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1311 struct symdef def = find_sym(p, s, 0);
1312 if (!def.sym) goto failed;
1313 if ((def.sym->st_info&0xf) == STT_TLS)
1314 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1315 return def.dso->base + def.sym->st_value;
1317 if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1321 sym = gnu_lookup(s, gh, p);
1324 sym = sysv_lookup(s, h, p);
1326 if (sym && (sym->st_info&0xf) == STT_TLS)
1327 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1328 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1329 return p->base + sym->st_value;
1330 if (p->deps) for (i=0; p->deps[i]; i++) {
1331 if (p->deps[i]->ghashtab) {
1332 if (!gh) gh = gnu_hash(s);
1333 sym = gnu_lookup(s, gh, p->deps[i]);
1335 if (!h) h = sysv_hash(s);
1336 sym = sysv_lookup(s, h, p->deps[i]);
1338 if (sym && (sym->st_info&0xf) == STT_TLS)
1339 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1340 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1341 return p->deps[i]->base + sym->st_value;
1345 snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1349 int __dladdr(const void *addr, Dl_info *info)
1359 pthread_rwlock_rdlock(&lock);
1360 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1361 pthread_rwlock_unlock(&lock);
1366 strings = p->strings;
1368 nsym = p->hashtab[1];
1372 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1373 sym += p->ghashtab[1];
1374 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1375 if (buckets[i] > nsym)
1379 nsym -= p->ghashtab[1];
1380 hashval = buckets + p->ghashtab[0] + nsym;
1382 while (!(*hashval++ & 1));
1386 for (; nsym; nsym--, sym++) {
1388 && (1<<(sym->st_info&0xf) & OK_TYPES)
1389 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1390 void *symaddr = p->base + sym->st_value;
1391 if (symaddr > addr || symaddr < best)
1394 bestname = strings + sym->st_name;
1395 if (addr == symaddr)
1400 if (!best) return 0;
1402 info->dli_fname = p->name;
1403 info->dli_fbase = p->base;
1404 info->dli_sname = bestname;
1405 info->dli_saddr = best;
1410 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1413 pthread_rwlock_rdlock(&lock);
1414 res = do_dlsym(p, s, ra);
1415 pthread_rwlock_unlock(&lock);
1419 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1421 struct dso *current;
1422 struct dl_phdr_info info;
1424 for(current = head; current;) {
1425 info.dlpi_addr = (uintptr_t)current->base;
1426 info.dlpi_name = current->name;
1427 info.dlpi_phdr = current->phdr;
1428 info.dlpi_phnum = current->phnum;
1429 info.dlpi_adds = gencnt;
1431 info.dlpi_tls_modid = current->tls_id;
1432 info.dlpi_tls_data = current->tls_image;
1434 ret = (callback)(&info, sizeof (info), data);
1436 if (ret != 0) break;
1438 pthread_rwlock_rdlock(&lock);
1439 current = current->next;
1440 pthread_rwlock_unlock(&lock);
1445 static int invalid_dso_handle(void *h)
1447 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1451 void *dlopen(const char *file, int mode)
1455 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1459 int __dladdr (const void *addr, Dl_info *info)
1465 int __dlinfo(void *dso, int req, void *res)
1467 if (invalid_dso_handle(dso)) return -1;
1468 if (req != RTLD_DI_LINKMAP) {
1469 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1473 *(struct link_map **)res = dso;
1479 if (!errflag) return 0;
1484 int dlclose(void *p)
1486 return invalid_dso_handle(p);