20 #include "pthread_impl.h"
25 static char errbuf[128];
29 #define MAXP2(a,b) (-(-(a)&-(b)))
30 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
42 struct td_index *next;
49 struct dso *next, *prev;
68 struct dso **deps, *needed_by;
69 char *rpath_orig, *rpath;
71 size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
72 size_t relro_start, relro_end;
74 unsigned char *new_tls;
75 volatile int new_dtv_idx, new_tls_idx;
76 struct td_index *td_index;
77 struct dso *fini_next;
78 int rel_early_relative, rel_update_got;
88 int __init_tp(void *);
89 void __init_libc(char **, char *);
91 const char *__libc_get_version(void);
93 static struct builtin_tls {
98 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
100 static struct dso ldso;
101 static struct dso *head, *tail, *fini_head;
102 static char *env_path, *sys_path;
103 static unsigned long long gencnt;
106 static int ldso_fail;
108 static jmp_buf *rtld_fail;
109 static pthread_rwlock_t lock;
110 static struct debug debug;
111 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
112 static size_t static_tls_cnt;
113 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
115 struct debug *_dl_debug_addr = &debug;
117 static int dl_strcmp(const char *l, const char *r)
119 for (; *l==*r && *l; l++, r++);
120 return *(unsigned char *)l - *(unsigned char *)r;
122 #define strcmp(l,r) dl_strcmp(l,r)
124 static void decode_vec(size_t *v, size_t *a, size_t cnt)
127 for (i=0; i<cnt; i++) a[i] = 0;
128 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
134 static int search_vec(size_t *v, size_t *r, size_t key)
136 for (; v[0]!=key; v+=2)
142 static void error(const char *fmt, ...)
146 vsnprintf(errbuf, sizeof errbuf, fmt, ap);
148 if (runtime) longjmp(*rtld_fail, 1);
149 dprintf(2, "%s\n", errbuf);
153 static uint32_t sysv_hash(const char *s0)
155 const unsigned char *s = (void *)s0;
161 return h & 0xfffffff;
164 static uint32_t gnu_hash(const char *s0)
166 const unsigned char *s = (void *)s0;
167 uint_fast32_t h = 5381;
173 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
176 Sym *syms = dso->syms;
177 uint32_t *hashtab = dso->hashtab;
178 char *strings = dso->strings;
179 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
180 if ((!dso->versym || dso->versym[i] >= 0)
181 && (!strcmp(s, strings+syms[i].st_name)))
187 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
189 Sym *syms = dso->syms;
190 char *strings = dso->strings;
191 uint32_t *hashtab = dso->ghashtab;
192 uint32_t nbuckets = hashtab[0];
193 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
196 uint32_t i = buckets[h1 % nbuckets];
200 hashval = buckets + nbuckets + (i - hashtab[1]);
202 for (h1 |= 1; ; i++) {
204 if ((!dso->versym || dso->versym[i] >= 0)
205 && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
213 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
214 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
216 #ifndef ARCH_SYM_REJECT_UND
217 #define ARCH_SYM_REJECT_UND(s) 0
220 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
222 uint32_t h = 0, gh = 0;
223 struct symdef def = {0};
224 for (; dso; dso=dso->next) {
226 if (!dso->global) continue;
228 if (!gh) gh = gnu_hash(s);
229 sym = gnu_lookup(s, gh, dso);
231 if (!h) h = sysv_hash(s);
232 sym = sysv_lookup(s, h, dso);
236 if (need_def || (sym->st_info&0xf) == STT_TLS
237 || ARCH_SYM_REJECT_UND(sym))
240 if ((sym->st_info&0xf) != STT_TLS)
242 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
243 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
245 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
248 if (sym->st_info>>4 == STB_GLOBAL) break;
253 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
255 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
257 unsigned char *base = dso->base;
258 Sym *syms = dso->syms;
259 char *strings = dso->strings;
271 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
272 if (dso->rel_early_relative && IS_RELATIVE(rel[1])) continue;
273 type = R_TYPE(rel[1]);
274 sym_index = R_SYM(rel[1]);
275 reloc_addr = (void *)(base + rel[0]);
277 sym = syms + sym_index;
278 name = strings + sym->st_name;
279 ctx = type==REL_COPY ? head->next : head;
280 def = find_sym(ctx, name, type==REL_PLT);
281 if (!def.sym && (sym->st_shndx != SHN_UNDEF
282 || sym->st_info>>4 != STB_WEAK)) {
283 error("Error relocating %s: %s: symbol not found",
293 int gotplt = (type == REL_GOT || type == REL_PLT);
294 if (dso->rel_update_got && !gotplt) continue;
296 addend = stride>2 ? rel[2]
297 : gotplt || type==REL_COPY ? 0
300 sym_val = def.sym ? (size_t)def.dso->base+def.sym->st_value : 0;
301 tls_val = def.sym ? def.sym->st_value : 0;
307 addend -= (size_t)reloc_addr;
311 *reloc_addr = sym_val + addend;
314 *reloc_addr = (size_t)base + addend;
317 if (sym) *reloc_addr = sym_val + addend;
318 else *reloc_addr = (size_t)base + addend;
321 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
324 *(uint32_t *)reloc_addr = sym_val + addend
325 - (size_t)reloc_addr;
328 *reloc_addr = def.dso->tls_id;
331 *reloc_addr = tls_val + addend;
335 *reloc_addr = tls_val + def.dso->tls_offset + TPOFF_K + addend;
339 *reloc_addr = tls_val - def.dso->tls_offset + addend;
342 *reloc_addr = def.dso->tls_offset - tls_val + addend;
346 if (stride<3) addend = reloc_addr[1];
347 if (runtime && def.dso->tls_id >= static_tls_cnt) {
348 struct td_index *new = malloc(sizeof *new);
350 "Error relocating %s: cannot allocate TLSDESC for %s",
351 dso->name, sym ? name : "(local)" );
352 new->next = dso->td_index;
354 new->args[0] = def.dso->tls_id;
355 new->args[1] = tls_val + addend;
356 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
357 reloc_addr[1] = (size_t)new;
359 reloc_addr[0] = (size_t)__tlsdesc_static;
361 reloc_addr[1] = tls_val + def.dso->tls_offset
364 reloc_addr[1] = tls_val - def.dso->tls_offset
370 error("Error relocating %s: unsupported relocation type %d",
377 /* A huge hack: to make up for the wastefulness of shared libraries
378 * needing at least a page of dirty memory even if they have no global
379 * data, we reclaim the gaps at the beginning and end of writable maps
380 * and "donate" them to the heap by setting up minimal malloc
381 * structures and then freeing them. */
383 static void reclaim(struct dso *dso, size_t start, size_t end)
386 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
387 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
388 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
389 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
390 if (start>end || end-start < 4*sizeof(size_t)) return;
391 a = (size_t *)(dso->base + start);
392 z = (size_t *)(dso->base + end);
394 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
399 static void reclaim_gaps(struct dso *dso)
401 Phdr *ph = dso->phdr;
402 size_t phcnt = dso->phnum;
404 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
405 if (ph->p_type!=PT_LOAD) continue;
406 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
407 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
408 reclaim(dso, ph->p_vaddr+ph->p_memsz,
409 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
413 static void *map_library(int fd, struct dso *dso)
415 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
416 void *allocated_buf=0;
418 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
419 size_t this_min, this_max;
424 unsigned char *map=MAP_FAILED, *base;
429 ssize_t l = read(fd, buf, sizeof buf);
432 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
434 phsize = eh->e_phentsize * eh->e_phnum;
435 if (phsize > sizeof buf - sizeof *eh) {
436 allocated_buf = malloc(phsize);
437 if (!allocated_buf) return 0;
438 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
439 if (l < 0) goto error;
440 if (l != phsize) goto noexec;
441 ph = ph0 = allocated_buf;
442 } else if (eh->e_phoff + phsize > l) {
443 l = pread(fd, buf+1, phsize, eh->e_phoff);
444 if (l < 0) goto error;
445 if (l != phsize) goto noexec;
446 ph = ph0 = (void *)(buf + 1);
448 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
450 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
451 if (ph->p_type == PT_DYNAMIC) {
453 } else if (ph->p_type == PT_TLS) {
454 tls_image = ph->p_vaddr;
455 dso->tls_align = ph->p_align;
456 dso->tls_len = ph->p_filesz;
457 dso->tls_size = ph->p_memsz;
458 } else if (ph->p_type == PT_GNU_RELRO) {
459 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
460 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
462 if (ph->p_type != PT_LOAD) continue;
463 if (ph->p_vaddr < addr_min) {
464 addr_min = ph->p_vaddr;
465 off_start = ph->p_offset;
466 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
467 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
468 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
470 if (ph->p_vaddr+ph->p_memsz > addr_max) {
471 addr_max = ph->p_vaddr+ph->p_memsz;
474 if (!dyn) goto noexec;
475 addr_max += PAGE_SIZE-1;
476 addr_max &= -PAGE_SIZE;
477 addr_min &= -PAGE_SIZE;
478 off_start &= -PAGE_SIZE;
479 map_len = addr_max - addr_min + off_start;
480 /* The first time, we map too much, possibly even more than
481 * the length of the file. This is okay because we will not
482 * use the invalid part; we just need to reserve the right
483 * amount of virtual address space to map over later. */
484 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
485 if (map==MAP_FAILED) goto error;
486 /* If the loaded file is not relocatable and the requested address is
487 * not available, then the load operation must fail. */
488 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
492 base = map - addr_min;
495 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
496 if (ph->p_type != PT_LOAD) continue;
497 /* Check if the programs headers are in this load segment, and
498 * if so, record the address for use by dl_iterate_phdr. */
499 if (!dso->phdr && eh->e_phoff >= ph->p_offset
500 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
501 dso->phdr = (void *)(base + ph->p_vaddr
502 + (eh->e_phoff-ph->p_offset));
503 dso->phnum = eh->e_phnum;
504 dso->phentsize = eh->e_phentsize;
506 /* Reuse the existing mapping for the lowest-address LOAD */
507 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
508 this_min = ph->p_vaddr & -PAGE_SIZE;
509 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
510 off_start = ph->p_offset & -PAGE_SIZE;
511 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
512 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
513 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
514 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
516 if (ph->p_memsz > ph->p_filesz) {
517 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
518 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
519 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
520 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)
524 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
525 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
526 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
531 dso->map_len = map_len;
533 dso->dynv = (void *)(base+dyn);
534 if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
535 if (!runtime) reclaim_gaps(dso);
541 if (map!=MAP_FAILED) munmap(map, map_len);
546 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
551 s += strspn(s, ":\n");
552 l = strcspn(s, ":\n");
553 if (l-1 >= INT_MAX) return -1;
554 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
555 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
563 /* Any negative value but -1 will inhibit
564 * futher path search. */
572 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
575 const char *s, *t, *origin;
577 if (p->rpath || !p->rpath_orig) return 0;
578 if (!strchr(p->rpath_orig, '$')) {
579 p->rpath = p->rpath_orig;
584 while ((t=strchr(s, '$'))) {
585 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
590 if (n > SSIZE_MAX/PATH_MAX) return 0;
592 if (p->kernel_mapped) {
593 /* $ORIGIN searches cannot be performed for the main program
594 * when it is suid/sgid/AT_SECURE. This is because the
595 * pathname is under the control of the caller of execve.
596 * For libraries, however, $ORIGIN can be processed safely
597 * since the library's pathname came from a trusted source
598 * (either system paths or a call to dlopen). */
601 l = readlink("/proc/self/exe", buf, buf_size);
602 if (l == -1) switch (errno) {
617 t = strrchr(origin, '/');
618 l = t ? t-origin : 0;
619 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
620 if (!p->rpath) return -1;
624 while ((t=strchr(s, '$'))) {
627 memcpy(d, origin, l);
629 /* It was determined previously that the '$' is followed
630 * either by "ORIGIN" or "{ORIGIN}". */
631 s = t + 7 + 2*(t[1]=='{');
637 static void decode_dyn(struct dso *p)
639 size_t dyn[DYN_CNT] = {0};
640 decode_vec(p->dynv, dyn, DYN_CNT);
641 p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
642 p->strings = (void *)(p->base + dyn[DT_STRTAB]);
643 if (dyn[0]&(1<<DT_HASH))
644 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
645 if (dyn[0]&(1<<DT_RPATH))
646 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
647 if (dyn[0]&(1<<DT_RUNPATH))
648 p->rpath_orig = (void *)(p->strings + dyn[DT_RUNPATH]);
649 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
650 p->ghashtab = (void *)(p->base + *dyn);
651 if (search_vec(p->dynv, dyn, DT_VERSYM))
652 p->versym = (void *)(p->base + *dyn);
655 static struct dso *load_library(const char *name, struct dso *needed_by)
657 char buf[2*NAME_MAX+2];
658 const char *pathname;
660 struct dso *p, temp_dso = {0};
672 /* Catch and block attempts to reload the implementation itself */
673 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
674 static const char *rp, reserved[] =
675 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
676 char *z = strchr(name, '.');
679 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
682 /* Track which names have been resolved
683 * and only report each one once. */
684 static unsigned reported;
685 unsigned mask = 1U<<(rp-reserved);
686 if (!(reported & mask)) {
688 dprintf(1, "\t%s => %s (%p)\n",
697 if (!strcmp(name, ldso.name)) is_self = 1;
702 tail = ldso.next ? ldso.next : &ldso;
706 if (strchr(name, '/')) {
708 fd = open(name, O_RDONLY|O_CLOEXEC);
710 /* Search for the name to see if it's already loaded */
711 for (p=head->next; p; p=p->next) {
712 if (p->shortname && !strcmp(p->shortname, name)) {
717 if (strlen(name) > NAME_MAX) return 0;
719 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
720 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
721 if (fixup_rpath(p, buf, sizeof buf) < 0)
722 fd = -2; /* Inhibit further search. */
724 fd = path_open(name, p->rpath, buf, sizeof buf);
730 if (ldso.name[0]=='/') {
732 for (s=t=z=ldso.name; *s; s++)
733 if (*s=='/') z=t, t=s;
734 prefix_len = z-ldso.name;
735 if (prefix_len < PATH_MAX)
742 char etc_ldso_path[prefix_len + 1
743 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
744 snprintf(etc_ldso_path, sizeof etc_ldso_path,
745 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
746 (int)prefix_len, prefix);
747 FILE *f = fopen(etc_ldso_path, "rbe");
749 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
754 } else if (errno != ENOENT) {
758 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
759 fd = path_open(name, sys_path, buf, sizeof buf);
763 if (fd < 0) return 0;
764 if (fstat(fd, &st) < 0) {
768 for (p=head->next; p; p=p->next) {
769 if (p->dev == st.st_dev && p->ino == st.st_ino) {
770 /* If this library was previously loaded with a
771 * pathname but a search found the same inode,
772 * setup its shortname so it can be found by name. */
773 if (!p->shortname && pathname != name)
774 p->shortname = strrchr(p->name, '/')+1;
780 map = noload ? 0 : map_library(fd, &temp_dso);
784 /* Allocate storage for the new DSO. When there is TLS, this
785 * storage must include a reservation for all pre-existing
786 * threads to obtain copies of both the new TLS, and an
787 * extended DTV capable of storing an additional slot for
788 * the newly-loaded DSO. */
789 alloc_size = sizeof *p + strlen(pathname) + 1;
790 if (runtime && temp_dso.tls_image) {
791 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
792 + sizeof(void *) * (tls_cnt+3);
793 n_th = libc.threads_minus_1 + 1;
794 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
795 else alloc_size += n_th * per_th;
797 p = calloc(1, alloc_size);
799 munmap(map, temp_dso.map_len);
802 memcpy(p, &temp_dso, sizeof temp_dso);
807 p->needed_by = needed_by;
809 strcpy(p->name, pathname);
810 /* Add a shortname only if name arg was not an explicit pathname. */
811 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
813 if (runtime && !libc.has_thread_pointer) {
814 munmap(map, p->map_len);
819 p->tls_id = ++tls_cnt;
820 tls_align = MAXP2(tls_align, p->tls_align);
822 p->tls_offset = tls_offset + ( (tls_align-1) &
823 -(tls_offset + (uintptr_t)p->tls_image) );
824 tls_offset += p->tls_size;
826 tls_offset += p->tls_size + p->tls_align - 1;
827 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
829 p->tls_offset = tls_offset;
831 p->new_dtv = (void *)(-sizeof(size_t) &
832 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
833 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
840 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
845 static void load_deps(struct dso *p)
848 struct dso ***deps = &p->deps, **tmp, *dep;
849 for (; p; p=p->next) {
850 for (i=0; p->dynv[i]; i+=2) {
851 if (p->dynv[i] != DT_NEEDED) continue;
852 dep = load_library(p->strings + p->dynv[i+1], p);
854 error("Error loading shared library %s: %m (needed by %s)",
855 p->strings + p->dynv[i+1], p->name);
859 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
860 if (!tmp) longjmp(*rtld_fail, 1);
869 static void load_preload(char *s)
874 for ( ; *s && (isspace(*s) || *s==':'); s++);
875 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
883 static void make_global(struct dso *p)
885 for (; p; p=p->next) p->global = 1;
888 static void do_mips_relocs(struct dso *p, size_t *got)
891 unsigned char *base = p->base;
892 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
893 if (p->rel_early_relative) {
896 while (i--) *got++ += (size_t)base;
898 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
899 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
900 Sym *sym = p->syms + j;
901 rel[0] = (unsigned char *)got - base;
902 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
903 rel[1] = sym-p->syms << 8 | R_MIPS_JUMP_SLOT;
904 do_relocs(p, rel, sizeof rel, 2);
908 static void reloc_all(struct dso *p)
910 size_t dyn[DYN_CNT] = {0};
911 for (; p; p=p->next) {
912 if (p->relocated) continue;
913 decode_vec(p->dynv, dyn, DYN_CNT);
914 if (NEED_MIPS_GOT_RELOCS)
915 do_mips_relocs(p, (void *)(p->base+dyn[DT_PLTGOT]));
916 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
917 2+(dyn[DT_PLTREL]==DT_RELA));
918 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
919 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
921 if (head != &ldso && p->relro_start != p->relro_end &&
922 mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) {
923 error("Error relocating %s: RELRO protection failed: %m",
931 static void kernel_mapped_dso(struct dso *p)
933 size_t min_addr = -1, max_addr = 0, cnt;
935 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
936 if (ph->p_type == PT_DYNAMIC) {
937 p->dynv = (void *)(p->base + ph->p_vaddr);
938 } else if (ph->p_type == PT_GNU_RELRO) {
939 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
940 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
942 if (ph->p_type != PT_LOAD) continue;
943 if (ph->p_vaddr < min_addr)
944 min_addr = ph->p_vaddr;
945 if (ph->p_vaddr+ph->p_memsz > max_addr)
946 max_addr = ph->p_vaddr+ph->p_memsz;
948 min_addr &= -PAGE_SIZE;
949 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
950 p->map = p->base + min_addr;
951 p->map_len = max_addr - min_addr;
952 p->kernel_mapped = 1;
955 static void do_fini()
958 size_t dyn[DYN_CNT] = {0};
959 for (p=fini_head; p; p=p->fini_next) {
960 if (!p->constructed) continue;
961 decode_vec(p->dynv, dyn, DYN_CNT);
962 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
963 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
964 size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
965 while (n--) ((void (*)(void))*--fn)();
967 #ifndef NO_LEGACY_INITFINI
968 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
969 ((void (*)(void))(p->base + dyn[DT_FINI]))();
974 static void do_init_fini(struct dso *p)
976 size_t dyn[DYN_CNT] = {0};
977 int need_locking = libc.threads_minus_1;
978 /* Allow recursive calls that arise when a library calls
979 * dlopen from one of its constructors, but block any
980 * other threads until all ctors have finished. */
981 if (need_locking) pthread_mutex_lock(&init_fini_lock);
982 for (; p; p=p->prev) {
983 if (p->constructed) continue;
985 decode_vec(p->dynv, dyn, DYN_CNT);
986 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
987 p->fini_next = fini_head;
990 #ifndef NO_LEGACY_INITFINI
991 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
992 ((void (*)(void))(p->base + dyn[DT_INIT]))();
994 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
995 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
996 size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
997 while (n--) ((void (*)(void))*fn++)();
999 if (!need_locking && libc.threads_minus_1) {
1001 pthread_mutex_lock(&init_fini_lock);
1004 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1007 void _dl_debug_state(void)
1013 pthread_t self = __pthread_self();
1015 for (p=head; p; p=p->next) {
1016 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
1017 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
1018 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
1019 p->tls_size - p->tls_len);
1020 if (p->tls_id == (size_t)self->dtv[0]) break;
1024 void *__copy_tls(unsigned char *mem)
1029 void **dtv = (void *)mem;
1030 dtv[0] = (void *)tls_cnt;
1032 td = (void *)(dtv+1);
1033 td->dtv = td->dtv_copy = dtv;
1038 mem += sizeof(void *) * (tls_cnt+1);
1039 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
1040 td = (pthread_t)mem;
1041 mem += sizeof(struct pthread);
1043 for (p=head; p; p=p->next) {
1044 if (!p->tls_id) continue;
1045 dtv[p->tls_id] = mem + p->tls_offset;
1046 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1049 mem += libc.tls_size - sizeof(struct pthread);
1050 mem -= (uintptr_t)mem & (tls_align-1);
1051 td = (pthread_t)mem;
1053 for (p=head; p; p=p->next) {
1054 if (!p->tls_id) continue;
1055 dtv[p->tls_id] = mem - p->tls_offset;
1056 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1059 td->dtv = td->dtv_copy = dtv;
1063 void *__tls_get_new(size_t *v)
1065 pthread_t self = __pthread_self();
1067 /* Block signals to make accessing new TLS async-signal-safe */
1069 __block_all_sigs(&set);
1070 if (v[0]<=(size_t)self->dtv[0]) {
1071 __restore_sigs(&set);
1072 return (char *)self->dtv[v[0]]+v[1];
1075 /* This is safe without any locks held because, if the caller
1076 * is able to request the Nth entry of the DTV, the DSO list
1077 * must be valid at least that far out and it was synchronized
1078 * at program startup or by an already-completed call to dlopen. */
1080 for (p=head; p->tls_id != v[0]; p=p->next);
1082 /* Get new DTV space from new DSO if needed */
1083 if (v[0] > (size_t)self->dtv[0]) {
1084 void **newdtv = p->new_dtv +
1085 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1086 memcpy(newdtv, self->dtv,
1087 ((size_t)self->dtv[0]+1) * sizeof(void *));
1088 newdtv[0] = (void *)v[0];
1089 self->dtv = self->dtv_copy = newdtv;
1092 /* Get new TLS memory from all new DSOs up to the requested one */
1094 for (p=head; ; p=p->next) {
1095 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1096 mem = p->new_tls + (p->tls_size + p->tls_align)
1097 * a_fetch_add(&p->new_tls_idx,1);
1098 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
1100 self->dtv[p->tls_id] = mem;
1101 memcpy(mem, p->tls_image, p->tls_len);
1102 if (p->tls_id == v[0]) break;
1104 __restore_sigs(&set);
1108 static void update_tls_size()
1110 libc.tls_size = ALIGN(
1111 (1+tls_cnt) * sizeof(void *) +
1113 sizeof(struct pthread) +
1118 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1119 * following stage 2 and stage 3 functions via primitive symbolic lookup
1120 * since it does not have access to their addresses to begin with. */
1122 /* Stage 2 of the dynamic linker is called after relative relocations
1123 * have been processed. It can make function calls to static functions
1124 * and access string literals and static data, but cannot use extern
1125 * symbols. Its job is to perform symbolic relocations on the dynamic
1126 * linker itself, but some of the relocations performed may need to be
1127 * replaced later due to copy relocations in the main program. */
1129 void __dls2(unsigned char *base)
1131 Ehdr *ehdr = (void *)base;
1133 ldso.name = ldso.shortname = "libc.so";
1135 ldso.phnum = ehdr->e_phnum;
1136 ldso.phdr = (void *)(base + ehdr->e_phoff);
1137 ldso.phentsize = ehdr->e_phentsize;
1138 ldso.rel_early_relative = 1;
1139 kernel_mapped_dso(&ldso);
1146 ldso.rel_update_got = 1;
1149 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1150 * fully functional. Its job is to load (if not already loaded) and
1151 * process dependencies and relocations for the main application and
1152 * transfer control to its entry point. */
1154 _Noreturn void __dls3(size_t *sp)
1156 static struct dso app, vdso;
1157 size_t aux[AUX_CNT] = {0}, *auxv;
1159 char *env_preload=0;
1162 char **argv = (void *)(sp+1);
1163 char **argv_orig = argv;
1164 char **envp = argv+argc+1;
1167 /* Find aux vector just past environ[] */
1168 for (i=argc+1; argv[i]; i++)
1169 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
1170 env_path = argv[i]+16;
1171 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
1172 env_preload = argv[i]+11;
1173 auxv = (void *)(argv+i+1);
1175 decode_vec(auxv, aux, AUX_CNT);
1177 /* Only trust user/env if kernel says we're not suid/sgid */
1178 if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1179 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
1184 libc.page_size = aux[AT_PAGESZ];
1187 /* If the main program was already loaded by the kernel,
1188 * AT_PHDR will point to some location other than the dynamic
1189 * linker's program headers. */
1190 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1191 size_t interp_off = 0;
1192 size_t tls_image = 0;
1193 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1194 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1195 app.phnum = aux[AT_PHNUM];
1196 app.phentsize = aux[AT_PHENT];
1197 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1198 if (phdr->p_type == PT_PHDR)
1199 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1200 else if (phdr->p_type == PT_INTERP)
1201 interp_off = (size_t)phdr->p_vaddr;
1202 else if (phdr->p_type == PT_TLS) {
1203 tls_image = phdr->p_vaddr;
1204 app.tls_len = phdr->p_filesz;
1205 app.tls_size = phdr->p_memsz;
1206 app.tls_align = phdr->p_align;
1209 if (app.tls_size) app.tls_image = (char *)app.base + tls_image;
1210 if (interp_off) ldso.name = (char *)app.base + interp_off;
1211 if ((aux[0] & (1UL<<AT_EXECFN))
1212 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1213 app.name = (char *)aux[AT_EXECFN];
1216 kernel_mapped_dso(&app);
1219 char *ldname = argv[0];
1220 size_t l = strlen(ldname);
1221 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1223 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1224 char *opt = argv[0]+2;
1225 *argv++ = (void *)-1;
1228 } else if (!memcmp(opt, "list", 5)) {
1230 } else if (!memcmp(opt, "library-path", 12)) {
1231 if (opt[12]=='=') env_path = opt+13;
1232 else if (opt[12]) *argv = 0;
1233 else if (*argv) env_path = *argv++;
1234 } else if (!memcmp(opt, "preload", 7)) {
1235 if (opt[7]=='=') env_preload = opt+8;
1236 else if (opt[7]) *argv = 0;
1237 else if (*argv) env_preload = *argv++;
1242 argv[-1] = (void *)(argc - (argv-argv_orig));
1244 dprintf(2, "musl libc\n"
1246 "Dynamic Program Loader\n"
1247 "Usage: %s [options] [--] pathname%s\n",
1248 __libc_get_version(), ldname,
1249 ldd_mode ? "" : " [args]");
1252 fd = open(argv[0], O_RDONLY);
1254 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1258 Ehdr *ehdr = (void *)map_library(fd, &app);
1260 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1267 aux[AT_ENTRY] = (size_t)app.base + ehdr->e_entry;
1268 /* Find the name that would have been used for the dynamic
1269 * linker had ldd not taken its place. */
1271 for (i=0; i<app.phnum; i++) {
1272 if (app.phdr[i].p_type == PT_INTERP)
1273 ldso.name = (void *)(app.base
1274 + app.phdr[i].p_vaddr);
1276 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1280 app.tls_id = tls_cnt = 1;
1283 tls_offset = app.tls_size
1284 + ( -((uintptr_t)app.tls_image + app.tls_size)
1285 & (app.tls_align-1) );
1287 tls_offset = app.tls_offset = app.tls_size
1288 + ( -((uintptr_t)app.tls_image + app.tls_size)
1289 & (app.tls_align-1) );
1291 tls_align = MAXP2(tls_align, app.tls_align);
1296 /* Attach to vdso, if provided by the kernel */
1297 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1298 Ehdr *ehdr = (void *)vdso_base;
1299 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1300 vdso.phnum = ehdr->e_phnum;
1301 vdso.phentsize = ehdr->e_phentsize;
1302 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1303 if (phdr->p_type == PT_DYNAMIC)
1304 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1305 if (phdr->p_type == PT_LOAD)
1306 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1309 vdso.shortname = "linux-gate.so.1";
1317 /* Initial dso chain consists only of the app. */
1320 /* Donate unused parts of app and library mapping to malloc */
1322 reclaim_gaps(&ldso);
1324 /* Load preload/needed libraries, add their symbols to the global
1325 * namespace, and perform all remaining relocations. */
1326 if (env_preload) load_preload(env_preload);
1330 #ifndef DYNAMIC_IS_RO
1331 for (i=0; app.dynv[i]; i+=2)
1332 if (app.dynv[i]==DT_DEBUG)
1333 app.dynv[i+1] = (size_t)&debug;
1336 /* The main program must be relocated LAST since it may contin
1337 * copy relocations which depend on libraries' relocations. */
1338 reloc_all(app.next);
1342 if (libc.tls_size > sizeof builtin_tls) {
1343 initial_tls = calloc(libc.tls_size, 1);
1345 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1346 argv[0], libc.tls_size);
1350 initial_tls = builtin_tls;
1352 if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
1353 dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
1356 static_tls_cnt = tls_cnt;
1358 if (ldso_fail) _exit(127);
1359 if (ldd_mode) _exit(0);
1361 /* Switch to runtime mode: any further failures in the dynamic
1362 * linker are a reportable failure rather than a fatal startup
1367 debug.bp = _dl_debug_state;
1369 debug.base = ldso.base;
1373 __init_libc(envp, argv[0]);
1378 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1382 void *dlopen(const char *file, int mode)
1384 struct dso *volatile p, *orig_tail, *next;
1385 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1390 if (!file) return head;
1392 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1393 pthread_rwlock_wrlock(&lock);
1397 orig_tls_cnt = tls_cnt;
1398 orig_tls_offset = tls_offset;
1399 orig_tls_align = tls_align;
1401 noload = mode & RTLD_NOLOAD;
1404 if (setjmp(*rtld_fail)) {
1405 /* Clean up anything new that was (partially) loaded */
1406 if (p && p->deps) for (i=0; p->deps[i]; i++)
1407 if (p->deps[i]->global < 0)
1408 p->deps[i]->global = 0;
1409 for (p=orig_tail->next; p; p=next) {
1411 munmap(p->map, p->map_len);
1412 while (p->td_index) {
1413 void *tmp = p->td_index->next;
1417 if (p->rpath != p->rpath_orig)
1422 tls_cnt = orig_tls_cnt;
1423 tls_offset = orig_tls_offset;
1424 tls_align = orig_tls_align;
1430 } else p = load_library(file, head);
1433 snprintf(errbuf, sizeof errbuf, noload ?
1434 "Library %s is not already loaded" :
1435 "Error loading shared library %s: %m",
1441 /* First load handling */
1444 if (p->deps) for (i=0; p->deps[i]; i++)
1445 if (!p->deps[i]->global)
1446 p->deps[i]->global = -1;
1447 if (!p->global) p->global = -1;
1449 if (p->deps) for (i=0; p->deps[i]; i++)
1450 if (p->deps[i]->global < 0)
1451 p->deps[i]->global = 0;
1452 if (p->global < 0) p->global = 0;
1455 if (mode & RTLD_GLOBAL) {
1456 if (p->deps) for (i=0; p->deps[i]; i++)
1457 p->deps[i]->global = 1;
1467 pthread_rwlock_unlock(&lock);
1468 if (p) do_init_fini(orig_tail);
1469 pthread_setcancelstate(cs, 0);
1473 static int invalid_dso_handle(void *h)
1476 for (p=head; p; p=p->next) if (h==p) return 0;
1477 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1482 void *__tls_get_addr(size_t *);
1484 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1487 uint32_t h = 0, gh = 0;
1489 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1490 if (p == RTLD_DEFAULT) {
1492 } else if (p == RTLD_NEXT) {
1493 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1497 struct symdef def = find_sym(p, s, 0);
1498 if (!def.sym) goto failed;
1499 if ((def.sym->st_info&0xf) == STT_TLS)
1500 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1501 return def.dso->base + def.sym->st_value;
1503 if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1507 sym = gnu_lookup(s, gh, p);
1510 sym = sysv_lookup(s, h, p);
1512 if (sym && (sym->st_info&0xf) == STT_TLS)
1513 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1514 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1515 return p->base + sym->st_value;
1516 if (p->deps) for (i=0; p->deps[i]; i++) {
1517 if (p->deps[i]->ghashtab) {
1518 if (!gh) gh = gnu_hash(s);
1519 sym = gnu_lookup(s, gh, p->deps[i]);
1521 if (!h) h = sysv_hash(s);
1522 sym = sysv_lookup(s, h, p->deps[i]);
1524 if (sym && (sym->st_info&0xf) == STT_TLS)
1525 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1526 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1527 return p->deps[i]->base + sym->st_value;
1531 snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1535 int __dladdr(const void *addr, Dl_info *info)
1545 pthread_rwlock_rdlock(&lock);
1546 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1547 pthread_rwlock_unlock(&lock);
1552 strings = p->strings;
1554 nsym = p->hashtab[1];
1558 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1559 sym += p->ghashtab[1];
1560 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1561 if (buckets[i] > nsym)
1565 nsym -= p->ghashtab[1];
1566 hashval = buckets + p->ghashtab[0] + nsym;
1568 while (!(*hashval++ & 1));
1572 for (; nsym; nsym--, sym++) {
1574 && (1<<(sym->st_info&0xf) & OK_TYPES)
1575 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1576 void *symaddr = p->base + sym->st_value;
1577 if (symaddr > addr || symaddr < best)
1580 bestname = strings + sym->st_name;
1581 if (addr == symaddr)
1586 if (!best) return 0;
1588 info->dli_fname = p->name;
1589 info->dli_fbase = p->base;
1590 info->dli_sname = bestname;
1591 info->dli_saddr = best;
1596 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1599 pthread_rwlock_rdlock(&lock);
1600 res = do_dlsym(p, s, ra);
1601 pthread_rwlock_unlock(&lock);
1605 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1607 struct dso *current;
1608 struct dl_phdr_info info;
1610 for(current = head; current;) {
1611 info.dlpi_addr = (uintptr_t)current->base;
1612 info.dlpi_name = current->name;
1613 info.dlpi_phdr = current->phdr;
1614 info.dlpi_phnum = current->phnum;
1615 info.dlpi_adds = gencnt;
1617 info.dlpi_tls_modid = current->tls_id;
1618 info.dlpi_tls_data = current->tls_image;
1620 ret = (callback)(&info, sizeof (info), data);
1622 if (ret != 0) break;
1624 pthread_rwlock_rdlock(&lock);
1625 current = current->next;
1626 pthread_rwlock_unlock(&lock);
1631 static int invalid_dso_handle(void *h)
1633 snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1637 void *dlopen(const char *file, int mode)
1639 strcpy(errbuf, "Dynamic loading not supported");
1643 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1646 snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1649 int __dladdr (const void *addr, Dl_info *info)
1655 int __dlinfo(void *dso, int req, void *res)
1657 if (invalid_dso_handle(dso)) return -1;
1658 if (req != RTLD_DI_LINKMAP) {
1659 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1663 *(struct link_map **)res = dso;
1669 if (!errflag) return 0;
1674 int dlclose(void *p)
1676 return invalid_dso_handle(p);