20 #include "pthread_impl.h"
24 static void error(const char *, ...);
28 #define MAXP2(a,b) (-(-(a)&-(b)))
29 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
41 struct td_index *next;
48 struct dso *next, *prev;
67 struct dso **deps, *needed_by;
68 char *rpath_orig, *rpath;
70 size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
71 size_t relro_start, relro_end;
73 unsigned char *new_tls;
74 volatile int new_dtv_idx, new_tls_idx;
75 struct td_index *td_index;
76 struct dso *fini_next;
86 int __init_tp(void *);
87 void __init_libc(char **, char *);
89 const char *__libc_get_version(void);
91 static struct builtin_tls {
96 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
98 #define ADDEND_LIMIT 4096
99 static size_t *saved_addends, *apply_addends_to;
101 static struct dso ldso;
102 static struct dso *head, *tail, *fini_head;
103 static char *env_path, *sys_path;
104 static unsigned long long gencnt;
107 static int ldso_fail;
109 static jmp_buf *rtld_fail;
110 static pthread_rwlock_t lock;
111 static struct debug debug;
112 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
113 static size_t static_tls_cnt;
114 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
116 struct debug *_dl_debug_addr = &debug;
118 static int dl_strcmp(const char *l, const char *r)
120 for (; *l==*r && *l; l++, r++);
121 return *(unsigned char *)l - *(unsigned char *)r;
123 #define strcmp(l,r) dl_strcmp(l,r)
125 static void decode_vec(size_t *v, size_t *a, size_t cnt)
128 for (i=0; i<cnt; i++) a[i] = 0;
129 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
135 static int search_vec(size_t *v, size_t *r, size_t key)
137 for (; v[0]!=key; v+=2)
143 static uint32_t sysv_hash(const char *s0)
145 const unsigned char *s = (void *)s0;
151 return h & 0xfffffff;
154 static uint32_t gnu_hash(const char *s0)
156 const unsigned char *s = (void *)s0;
157 uint_fast32_t h = 5381;
163 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
166 Sym *syms = dso->syms;
167 uint32_t *hashtab = dso->hashtab;
168 char *strings = dso->strings;
169 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
170 if ((!dso->versym || dso->versym[i] >= 0)
171 && (!strcmp(s, strings+syms[i].st_name)))
177 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
179 Sym *syms = dso->syms;
180 char *strings = dso->strings;
181 uint32_t *hashtab = dso->ghashtab;
182 uint32_t nbuckets = hashtab[0];
183 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
186 uint32_t i = buckets[h1 % nbuckets];
190 hashval = buckets + nbuckets + (i - hashtab[1]);
192 for (h1 |= 1; ; i++) {
194 if ((!dso->versym || dso->versym[i] >= 0)
195 && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
203 static Sym *gnu_lookup_filtered(const char *s, uint32_t h1, struct dso *dso, uint32_t fofs, size_t fmask)
205 uint32_t *hashtab = dso->ghashtab;
206 const size_t *bloomwords = (const void *)(hashtab+4);
207 size_t f = bloomwords[fofs & (hashtab[2]-1)];
208 if (!(f & fmask)) return 0;
210 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
211 if (!(f & 1)) return 0;
213 return gnu_lookup(s, h1, dso);
216 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
217 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
219 #ifndef ARCH_SYM_REJECT_UND
220 #define ARCH_SYM_REJECT_UND(s) 0
223 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
225 uint32_t h = 0, gh, gho;
227 struct symdef def = {0};
228 for (; dso; dso=dso->next) {
230 if (!dso->global) continue;
234 int maskbits = 8 * sizeof ghm;
236 ghm = 1ul << gh % maskbits;
238 sym = gnu_lookup_filtered(s, gh, dso, gho, ghm);
240 if (!h) h = sysv_hash(s);
241 sym = sysv_lookup(s, h, dso);
245 if (need_def || (sym->st_info&0xf) == STT_TLS
246 || ARCH_SYM_REJECT_UND(sym))
249 if ((sym->st_info&0xf) != STT_TLS)
251 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
252 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
254 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
257 if (sym->st_info>>4 == STB_GLOBAL) break;
262 __attribute__((__visibility__("hidden")))
263 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
265 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
267 unsigned char *base = dso->base;
268 Sym *syms = dso->syms;
269 char *strings = dso->strings;
280 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
283 /* Only ldso's REL table needs addend saving/reuse. */
284 if (rel == apply_addends_to)
289 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
290 if (skip_relative && IS_RELATIVE(rel[1])) continue;
291 type = R_TYPE(rel[1]);
292 if (type == REL_NONE) continue;
293 sym_index = R_SYM(rel[1]);
294 reloc_addr = (void *)(base + rel[0]);
296 sym = syms + sym_index;
297 name = strings + sym->st_name;
298 ctx = type==REL_COPY ? head->next : head;
299 def = find_sym(ctx, name, type==REL_PLT);
300 if (!def.sym && (sym->st_shndx != SHN_UNDEF
301 || sym->st_info>>4 != STB_WEAK)) {
302 error("Error relocating %s: %s: symbol not found",
304 if (runtime) longjmp(*rtld_fail, 1);
315 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
317 } else if (reuse_addends) {
318 /* Save original addend in stage 2 where the dso
319 * chain consists of just ldso; otherwise read back
320 * saved addend since the inline one was clobbered. */
322 saved_addends[save_slot] = *reloc_addr;
323 addend = saved_addends[save_slot++];
325 addend = *reloc_addr;
328 sym_val = def.sym ? (size_t)def.dso->base+def.sym->st_value : 0;
329 tls_val = def.sym ? def.sym->st_value : 0;
335 addend -= (size_t)reloc_addr;
339 *reloc_addr = sym_val + addend;
342 *reloc_addr = (size_t)base + addend;
345 if (sym) *reloc_addr = sym_val + addend;
346 else *reloc_addr = (size_t)base + addend;
349 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
352 *(uint32_t *)reloc_addr = sym_val + addend
353 - (size_t)reloc_addr;
356 *reloc_addr = def.dso->tls_id;
359 *reloc_addr = tls_val + addend - DTP_OFFSET;
363 *reloc_addr = tls_val + def.dso->tls_offset + TPOFF_K + addend;
367 *reloc_addr = tls_val - def.dso->tls_offset + addend;
370 *reloc_addr = def.dso->tls_offset - tls_val + addend;
374 if (stride<3) addend = reloc_addr[1];
375 if (runtime && def.dso->tls_id >= static_tls_cnt) {
376 struct td_index *new = malloc(sizeof *new);
379 "Error relocating %s: cannot allocate TLSDESC for %s",
380 dso->name, sym ? name : "(local)" );
381 longjmp(*rtld_fail, 1);
383 new->next = dso->td_index;
385 new->args[0] = def.dso->tls_id;
386 new->args[1] = tls_val + addend;
387 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
388 reloc_addr[1] = (size_t)new;
390 reloc_addr[0] = (size_t)__tlsdesc_static;
392 reloc_addr[1] = tls_val + def.dso->tls_offset
395 reloc_addr[1] = tls_val - def.dso->tls_offset
401 error("Error relocating %s: unsupported relocation type %d",
403 if (runtime) longjmp(*rtld_fail, 1);
409 /* A huge hack: to make up for the wastefulness of shared libraries
410 * needing at least a page of dirty memory even if they have no global
411 * data, we reclaim the gaps at the beginning and end of writable maps
412 * and "donate" them to the heap by setting up minimal malloc
413 * structures and then freeing them. */
415 static void reclaim(struct dso *dso, size_t start, size_t end)
418 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
419 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
420 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
421 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
422 if (start>end || end-start < 4*sizeof(size_t)) return;
423 a = (size_t *)(dso->base + start);
424 z = (size_t *)(dso->base + end);
426 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
431 static void reclaim_gaps(struct dso *dso)
433 Phdr *ph = dso->phdr;
434 size_t phcnt = dso->phnum;
436 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
437 if (ph->p_type!=PT_LOAD) continue;
438 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
439 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
440 reclaim(dso, ph->p_vaddr+ph->p_memsz,
441 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
445 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
447 char *q = mmap(p, n, prot, flags, fd, off);
448 if (q != MAP_FAILED || errno != EINVAL) return q;
449 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
450 if (flags & MAP_ANONYMOUS) {
455 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
456 for (q=p; n; q+=r, off+=r, n-=r) {
458 if (r < 0 && errno != EINTR) return MAP_FAILED;
467 static void *map_library(int fd, struct dso *dso)
469 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
470 void *allocated_buf=0;
472 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
473 size_t this_min, this_max;
478 unsigned char *map=MAP_FAILED, *base;
483 ssize_t l = read(fd, buf, sizeof buf);
486 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
488 phsize = eh->e_phentsize * eh->e_phnum;
489 if (phsize > sizeof buf - sizeof *eh) {
490 allocated_buf = malloc(phsize);
491 if (!allocated_buf) return 0;
492 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
493 if (l < 0) goto error;
494 if (l != phsize) goto noexec;
495 ph = ph0 = allocated_buf;
496 } else if (eh->e_phoff + phsize > l) {
497 l = pread(fd, buf+1, phsize, eh->e_phoff);
498 if (l < 0) goto error;
499 if (l != phsize) goto noexec;
500 ph = ph0 = (void *)(buf + 1);
502 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
504 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
505 if (ph->p_type == PT_DYNAMIC) {
507 } else if (ph->p_type == PT_TLS) {
508 tls_image = ph->p_vaddr;
509 dso->tls_align = ph->p_align;
510 dso->tls_len = ph->p_filesz;
511 dso->tls_size = ph->p_memsz;
512 } else if (ph->p_type == PT_GNU_RELRO) {
513 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
514 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
516 if (ph->p_type != PT_LOAD) continue;
517 if (ph->p_vaddr < addr_min) {
518 addr_min = ph->p_vaddr;
519 off_start = ph->p_offset;
520 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
521 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
522 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
524 if (ph->p_vaddr+ph->p_memsz > addr_max) {
525 addr_max = ph->p_vaddr+ph->p_memsz;
528 if (!dyn) goto noexec;
529 addr_max += PAGE_SIZE-1;
530 addr_max &= -PAGE_SIZE;
531 addr_min &= -PAGE_SIZE;
532 off_start &= -PAGE_SIZE;
533 map_len = addr_max - addr_min + off_start;
534 /* The first time, we map too much, possibly even more than
535 * the length of the file. This is okay because we will not
536 * use the invalid part; we just need to reserve the right
537 * amount of virtual address space to map over later. */
538 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
539 if (map==MAP_FAILED) goto error;
540 /* If the loaded file is not relocatable and the requested address is
541 * not available, then the load operation must fail. */
542 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
546 base = map - addr_min;
549 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
550 if (ph->p_type != PT_LOAD) continue;
551 /* Check if the programs headers are in this load segment, and
552 * if so, record the address for use by dl_iterate_phdr. */
553 if (!dso->phdr && eh->e_phoff >= ph->p_offset
554 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
555 dso->phdr = (void *)(base + ph->p_vaddr
556 + (eh->e_phoff-ph->p_offset));
557 dso->phnum = eh->e_phnum;
558 dso->phentsize = eh->e_phentsize;
560 /* Reuse the existing mapping for the lowest-address LOAD */
561 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
562 this_min = ph->p_vaddr & -PAGE_SIZE;
563 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
564 off_start = ph->p_offset & -PAGE_SIZE;
565 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
566 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
567 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
568 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
570 if (ph->p_memsz > ph->p_filesz) {
571 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
572 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
573 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
574 if (pgbrk-(size_t)base < this_max && mmap_fixed((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED)
578 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
579 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
580 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
586 dso->map_len = map_len;
588 dso->dynv = (void *)(base+dyn);
589 if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
590 if (!runtime) reclaim_gaps(dso);
596 if (map!=MAP_FAILED) munmap(map, map_len);
601 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
606 s += strspn(s, ":\n");
607 l = strcspn(s, ":\n");
608 if (l-1 >= INT_MAX) return -1;
609 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
610 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
618 /* Any negative value but -1 will inhibit
619 * futher path search. */
627 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
630 const char *s, *t, *origin;
632 if (p->rpath || !p->rpath_orig) return 0;
633 if (!strchr(p->rpath_orig, '$')) {
634 p->rpath = p->rpath_orig;
639 while ((t=strchr(s, '$'))) {
640 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
645 if (n > SSIZE_MAX/PATH_MAX) return 0;
647 if (p->kernel_mapped) {
648 /* $ORIGIN searches cannot be performed for the main program
649 * when it is suid/sgid/AT_SECURE. This is because the
650 * pathname is under the control of the caller of execve.
651 * For libraries, however, $ORIGIN can be processed safely
652 * since the library's pathname came from a trusted source
653 * (either system paths or a call to dlopen). */
656 l = readlink("/proc/self/exe", buf, buf_size);
657 if (l == -1) switch (errno) {
672 t = strrchr(origin, '/');
673 l = t ? t-origin : 0;
674 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
675 if (!p->rpath) return -1;
679 while ((t=strchr(s, '$'))) {
682 memcpy(d, origin, l);
684 /* It was determined previously that the '$' is followed
685 * either by "ORIGIN" or "{ORIGIN}". */
686 s = t + 7 + 2*(t[1]=='{');
692 static void decode_dyn(struct dso *p)
695 decode_vec(p->dynv, dyn, DYN_CNT);
696 p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
697 p->strings = (void *)(p->base + dyn[DT_STRTAB]);
698 if (dyn[0]&(1<<DT_HASH))
699 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
700 if (dyn[0]&(1<<DT_RPATH))
701 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
702 if (dyn[0]&(1<<DT_RUNPATH))
703 p->rpath_orig = (void *)(p->strings + dyn[DT_RUNPATH]);
704 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
705 p->ghashtab = (void *)(p->base + *dyn);
706 if (search_vec(p->dynv, dyn, DT_VERSYM))
707 p->versym = (void *)(p->base + *dyn);
710 static struct dso *load_library(const char *name, struct dso *needed_by)
712 char buf[2*NAME_MAX+2];
713 const char *pathname;
715 struct dso *p, temp_dso = {0};
727 /* Catch and block attempts to reload the implementation itself */
728 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
729 static const char *rp, reserved[] =
730 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
731 char *z = strchr(name, '.');
734 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
737 /* Track which names have been resolved
738 * and only report each one once. */
739 static unsigned reported;
740 unsigned mask = 1U<<(rp-reserved);
741 if (!(reported & mask)) {
743 dprintf(1, "\t%s => %s (%p)\n",
752 if (!strcmp(name, ldso.name)) is_self = 1;
757 tail = ldso.next ? ldso.next : &ldso;
761 if (strchr(name, '/')) {
763 fd = open(name, O_RDONLY|O_CLOEXEC);
765 /* Search for the name to see if it's already loaded */
766 for (p=head->next; p; p=p->next) {
767 if (p->shortname && !strcmp(p->shortname, name)) {
772 if (strlen(name) > NAME_MAX) return 0;
774 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
775 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
776 if (fixup_rpath(p, buf, sizeof buf) < 0)
777 fd = -2; /* Inhibit further search. */
779 fd = path_open(name, p->rpath, buf, sizeof buf);
785 if (ldso.name[0]=='/') {
787 for (s=t=z=ldso.name; *s; s++)
788 if (*s=='/') z=t, t=s;
789 prefix_len = z-ldso.name;
790 if (prefix_len < PATH_MAX)
797 char etc_ldso_path[prefix_len + 1
798 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
799 snprintf(etc_ldso_path, sizeof etc_ldso_path,
800 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
801 (int)prefix_len, prefix);
802 FILE *f = fopen(etc_ldso_path, "rbe");
804 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
809 } else if (errno != ENOENT) {
813 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
814 fd = path_open(name, sys_path, buf, sizeof buf);
818 if (fd < 0) return 0;
819 if (fstat(fd, &st) < 0) {
823 for (p=head->next; p; p=p->next) {
824 if (p->dev == st.st_dev && p->ino == st.st_ino) {
825 /* If this library was previously loaded with a
826 * pathname but a search found the same inode,
827 * setup its shortname so it can be found by name. */
828 if (!p->shortname && pathname != name)
829 p->shortname = strrchr(p->name, '/')+1;
835 map = noload ? 0 : map_library(fd, &temp_dso);
839 /* Allocate storage for the new DSO. When there is TLS, this
840 * storage must include a reservation for all pre-existing
841 * threads to obtain copies of both the new TLS, and an
842 * extended DTV capable of storing an additional slot for
843 * the newly-loaded DSO. */
844 alloc_size = sizeof *p + strlen(pathname) + 1;
845 if (runtime && temp_dso.tls_image) {
846 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
847 + sizeof(void *) * (tls_cnt+3);
848 n_th = libc.threads_minus_1 + 1;
849 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
850 else alloc_size += n_th * per_th;
852 p = calloc(1, alloc_size);
854 munmap(map, temp_dso.map_len);
857 memcpy(p, &temp_dso, sizeof temp_dso);
862 p->needed_by = needed_by;
864 strcpy(p->name, pathname);
865 /* Add a shortname only if name arg was not an explicit pathname. */
866 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
868 p->tls_id = ++tls_cnt;
869 tls_align = MAXP2(tls_align, p->tls_align);
871 p->tls_offset = tls_offset + ( (tls_align-1) &
872 -(tls_offset + (uintptr_t)p->tls_image) );
873 tls_offset += p->tls_size;
875 tls_offset += p->tls_size + p->tls_align - 1;
876 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
878 p->tls_offset = tls_offset;
880 p->new_dtv = (void *)(-sizeof(size_t) &
881 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
882 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
889 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
894 static void load_deps(struct dso *p)
897 struct dso ***deps = &p->deps, **tmp, *dep;
898 for (; p; p=p->next) {
899 for (i=0; p->dynv[i]; i+=2) {
900 if (p->dynv[i] != DT_NEEDED) continue;
901 dep = load_library(p->strings + p->dynv[i+1], p);
903 error("Error loading shared library %s: %m (needed by %s)",
904 p->strings + p->dynv[i+1], p->name);
905 if (runtime) longjmp(*rtld_fail, 1);
909 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
910 if (!tmp) longjmp(*rtld_fail, 1);
919 static void load_preload(char *s)
924 for ( ; *s && (isspace(*s) || *s==':'); s++);
925 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
933 static void make_global(struct dso *p)
935 for (; p; p=p->next) p->global = 1;
938 static void do_mips_relocs(struct dso *p, size_t *got)
941 unsigned char *base = p->base;
942 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
946 while (i--) *got++ += (size_t)base;
948 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
949 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
950 Sym *sym = p->syms + j;
951 rel[0] = (unsigned char *)got - base;
952 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
953 rel[1] = sym-p->syms << 8 | R_MIPS_JUMP_SLOT;
954 do_relocs(p, rel, sizeof rel, 2);
958 static void reloc_all(struct dso *p)
961 for (; p; p=p->next) {
962 if (p->relocated) continue;
963 decode_vec(p->dynv, dyn, DYN_CNT);
964 if (NEED_MIPS_GOT_RELOCS)
965 do_mips_relocs(p, (void *)(p->base+dyn[DT_PLTGOT]));
966 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
967 2+(dyn[DT_PLTREL]==DT_RELA));
968 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
969 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
971 if (head != &ldso && p->relro_start != p->relro_end &&
972 mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ)
973 && errno != ENOSYS) {
974 error("Error relocating %s: RELRO protection failed: %m",
976 if (runtime) longjmp(*rtld_fail, 1);
983 static void kernel_mapped_dso(struct dso *p)
985 size_t min_addr = -1, max_addr = 0, cnt;
987 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
988 if (ph->p_type == PT_DYNAMIC) {
989 p->dynv = (void *)(p->base + ph->p_vaddr);
990 } else if (ph->p_type == PT_GNU_RELRO) {
991 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
992 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
994 if (ph->p_type != PT_LOAD) continue;
995 if (ph->p_vaddr < min_addr)
996 min_addr = ph->p_vaddr;
997 if (ph->p_vaddr+ph->p_memsz > max_addr)
998 max_addr = ph->p_vaddr+ph->p_memsz;
1000 min_addr &= -PAGE_SIZE;
1001 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1002 p->map = p->base + min_addr;
1003 p->map_len = max_addr - min_addr;
1004 p->kernel_mapped = 1;
1007 static void do_fini()
1010 size_t dyn[DYN_CNT];
1011 for (p=fini_head; p; p=p->fini_next) {
1012 if (!p->constructed) continue;
1013 decode_vec(p->dynv, dyn, DYN_CNT);
1014 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1015 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1016 size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
1017 while (n--) ((void (*)(void))*--fn)();
1019 #ifndef NO_LEGACY_INITFINI
1020 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1021 ((void (*)(void))(p->base + dyn[DT_FINI]))();
1026 static void do_init_fini(struct dso *p)
1028 size_t dyn[DYN_CNT];
1029 int need_locking = libc.threads_minus_1;
1030 /* Allow recursive calls that arise when a library calls
1031 * dlopen from one of its constructors, but block any
1032 * other threads until all ctors have finished. */
1033 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1034 for (; p; p=p->prev) {
1035 if (p->constructed) continue;
1037 decode_vec(p->dynv, dyn, DYN_CNT);
1038 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1039 p->fini_next = fini_head;
1042 #ifndef NO_LEGACY_INITFINI
1043 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1044 ((void (*)(void))(p->base + dyn[DT_INIT]))();
1046 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1047 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1048 size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
1049 while (n--) ((void (*)(void))*fn++)();
1051 if (!need_locking && libc.threads_minus_1) {
1053 pthread_mutex_lock(&init_fini_lock);
1056 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1059 static void dl_debug_state(void)
1063 weak_alias(dl_debug_state, _dl_debug_state);
1067 pthread_t self = __pthread_self();
1069 for (p=head; p; p=p->next) {
1070 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
1071 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
1072 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
1073 p->tls_size - p->tls_len);
1074 if (p->tls_id == (size_t)self->dtv[0]) break;
1078 void *__copy_tls(unsigned char *mem)
1085 dtv = (void **)(mem + libc.tls_size) - (tls_cnt + 1);
1087 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
1088 td = (pthread_t)mem;
1089 mem += sizeof(struct pthread);
1091 for (p=head; p; p=p->next) {
1092 if (!p->tls_id) continue;
1093 dtv[p->tls_id] = mem + p->tls_offset;
1094 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1099 mem += libc.tls_size - sizeof(struct pthread);
1100 mem -= (uintptr_t)mem & (tls_align-1);
1101 td = (pthread_t)mem;
1103 for (p=head; p; p=p->next) {
1104 if (!p->tls_id) continue;
1105 dtv[p->tls_id] = mem - p->tls_offset;
1106 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1109 dtv[0] = (void *)tls_cnt;
1110 td->dtv = td->dtv_copy = dtv;
1114 __attribute__((__visibility__("hidden")))
1115 void *__tls_get_new(size_t *v)
1117 pthread_t self = __pthread_self();
1119 /* Block signals to make accessing new TLS async-signal-safe */
1121 __block_all_sigs(&set);
1122 if (v[0]<=(size_t)self->dtv[0]) {
1123 __restore_sigs(&set);
1124 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1127 /* This is safe without any locks held because, if the caller
1128 * is able to request the Nth entry of the DTV, the DSO list
1129 * must be valid at least that far out and it was synchronized
1130 * at program startup or by an already-completed call to dlopen. */
1132 for (p=head; p->tls_id != v[0]; p=p->next);
1134 /* Get new DTV space from new DSO if needed */
1135 if (v[0] > (size_t)self->dtv[0]) {
1136 void **newdtv = p->new_dtv +
1137 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1138 memcpy(newdtv, self->dtv,
1139 ((size_t)self->dtv[0]+1) * sizeof(void *));
1140 newdtv[0] = (void *)v[0];
1141 self->dtv = self->dtv_copy = newdtv;
1144 /* Get new TLS memory from all new DSOs up to the requested one */
1146 for (p=head; ; p=p->next) {
1147 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1148 mem = p->new_tls + (p->tls_size + p->tls_align)
1149 * a_fetch_add(&p->new_tls_idx,1);
1150 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
1152 self->dtv[p->tls_id] = mem;
1153 memcpy(mem, p->tls_image, p->tls_len);
1154 if (p->tls_id == v[0]) break;
1156 __restore_sigs(&set);
1157 return mem + v[1] + DTP_OFFSET;
1160 static void update_tls_size()
1162 libc.tls_size = ALIGN(
1163 (1+tls_cnt) * sizeof(void *) +
1165 sizeof(struct pthread) +
1170 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1171 * following stage 2 and stage 3 functions via primitive symbolic lookup
1172 * since it does not have access to their addresses to begin with. */
1174 /* Stage 2 of the dynamic linker is called after relative relocations
1175 * have been processed. It can make function calls to static functions
1176 * and access string literals and static data, but cannot use extern
1177 * symbols. Its job is to perform symbolic relocations on the dynamic
1178 * linker itself, but some of the relocations performed may need to be
1179 * replaced later due to copy relocations in the main program. */
1181 void __dls2(unsigned char *base, size_t *sp)
1183 Ehdr *ehdr = (void *)base;
1185 ldso.name = ldso.shortname = "libc.so";
1187 ldso.phnum = ehdr->e_phnum;
1188 ldso.phdr = (void *)(base + ehdr->e_phoff);
1189 ldso.phentsize = ehdr->e_phentsize;
1190 kernel_mapped_dso(&ldso);
1193 /* Prepare storage for to save clobbered REL addends so they
1194 * can be reused in stage 3. There should be very few. If
1195 * something goes wrong and there are a huge number, abort
1196 * instead of risking stack overflow. */
1197 size_t dyn[DYN_CNT];
1198 decode_vec(ldso.dynv, dyn, DYN_CNT);
1199 size_t *rel = (void *)(base+dyn[DT_REL]);
1200 size_t rel_size = dyn[DT_RELSZ];
1201 size_t symbolic_rel_cnt = 0;
1202 apply_addends_to = rel;
1203 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1204 if (!IS_RELATIVE(rel[1])) symbolic_rel_cnt++;
1205 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1206 size_t addends[symbolic_rel_cnt+1];
1207 saved_addends = addends;
1214 /* Call dynamic linker stage-3, __dls3, looking it up
1215 * symbolically as a barrier against moving the address
1216 * load across the above relocation processing. */
1217 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1218 ((stage3_func)(ldso.base+dls3_def.sym->st_value))(sp);
1221 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1222 * fully functional. Its job is to load (if not already loaded) and
1223 * process dependencies and relocations for the main application and
1224 * transfer control to its entry point. */
1226 _Noreturn void __dls3(size_t *sp)
1228 static struct dso app, vdso;
1229 size_t aux[AUX_CNT], *auxv;
1231 char *env_preload=0;
1234 char **argv = (void *)(sp+1);
1235 char **argv_orig = argv;
1236 char **envp = argv+argc+1;
1238 /* Find aux vector just past environ[] and use it to initialize
1239 * global data that may be needed before we can make syscalls. */
1241 for (i=argc+1; argv[i]; i++);
1242 libc.auxv = auxv = (void *)(argv+i+1);
1243 decode_vec(auxv, aux, AUX_CNT);
1244 __hwcap = aux[AT_HWCAP];
1245 libc.page_size = aux[AT_PAGESZ];
1246 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1247 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1249 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1250 * use during dynamic linking. If possible it will also serve as the
1251 * thread pointer at runtime. */
1252 libc.tls_size = sizeof builtin_tls;
1253 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1257 /* Only trust user/env if kernel says we're not suid/sgid */
1259 env_path = getenv("LD_LIBRARY_PATH");
1260 env_preload = getenv("LD_PRELOAD");
1263 /* If the main program was already loaded by the kernel,
1264 * AT_PHDR will point to some location other than the dynamic
1265 * linker's program headers. */
1266 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1267 size_t interp_off = 0;
1268 size_t tls_image = 0;
1269 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1270 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1271 app.phnum = aux[AT_PHNUM];
1272 app.phentsize = aux[AT_PHENT];
1273 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1274 if (phdr->p_type == PT_PHDR)
1275 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1276 else if (phdr->p_type == PT_INTERP)
1277 interp_off = (size_t)phdr->p_vaddr;
1278 else if (phdr->p_type == PT_TLS) {
1279 tls_image = phdr->p_vaddr;
1280 app.tls_len = phdr->p_filesz;
1281 app.tls_size = phdr->p_memsz;
1282 app.tls_align = phdr->p_align;
1285 if (app.tls_size) app.tls_image = (char *)app.base + tls_image;
1286 if (interp_off) ldso.name = (char *)app.base + interp_off;
1287 if ((aux[0] & (1UL<<AT_EXECFN))
1288 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1289 app.name = (char *)aux[AT_EXECFN];
1292 kernel_mapped_dso(&app);
1295 char *ldname = argv[0];
1296 size_t l = strlen(ldname);
1297 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1299 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1300 char *opt = argv[0]+2;
1301 *argv++ = (void *)-1;
1304 } else if (!memcmp(opt, "list", 5)) {
1306 } else if (!memcmp(opt, "library-path", 12)) {
1307 if (opt[12]=='=') env_path = opt+13;
1308 else if (opt[12]) *argv = 0;
1309 else if (*argv) env_path = *argv++;
1310 } else if (!memcmp(opt, "preload", 7)) {
1311 if (opt[7]=='=') env_preload = opt+8;
1312 else if (opt[7]) *argv = 0;
1313 else if (*argv) env_preload = *argv++;
1318 argv[-1] = (void *)(argc - (argv-argv_orig));
1320 dprintf(2, "musl libc\n"
1322 "Dynamic Program Loader\n"
1323 "Usage: %s [options] [--] pathname%s\n",
1324 __libc_get_version(), ldname,
1325 ldd_mode ? "" : " [args]");
1328 fd = open(argv[0], O_RDONLY);
1330 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1334 Ehdr *ehdr = (void *)map_library(fd, &app);
1336 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1343 aux[AT_ENTRY] = (size_t)app.base + ehdr->e_entry;
1344 /* Find the name that would have been used for the dynamic
1345 * linker had ldd not taken its place. */
1347 for (i=0; i<app.phnum; i++) {
1348 if (app.phdr[i].p_type == PT_INTERP)
1349 ldso.name = (void *)(app.base
1350 + app.phdr[i].p_vaddr);
1352 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1356 app.tls_id = tls_cnt = 1;
1359 tls_offset = app.tls_size
1360 + ( -((uintptr_t)app.tls_image + app.tls_size)
1361 & (app.tls_align-1) );
1363 tls_offset = app.tls_offset = app.tls_size
1364 + ( -((uintptr_t)app.tls_image + app.tls_size)
1365 & (app.tls_align-1) );
1367 tls_align = MAXP2(tls_align, app.tls_align);
1372 /* Attach to vdso, if provided by the kernel */
1373 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1374 Ehdr *ehdr = (void *)vdso_base;
1375 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1376 vdso.phnum = ehdr->e_phnum;
1377 vdso.phentsize = ehdr->e_phentsize;
1378 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1379 if (phdr->p_type == PT_DYNAMIC)
1380 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1381 if (phdr->p_type == PT_LOAD)
1382 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1385 vdso.shortname = "linux-gate.so.1";
1393 /* Initial dso chain consists only of the app. */
1396 /* Donate unused parts of app and library mapping to malloc */
1398 reclaim_gaps(&ldso);
1400 /* Load preload/needed libraries, add their symbols to the global
1401 * namespace, and perform all remaining relocations. */
1402 if (env_preload) load_preload(env_preload);
1406 #ifndef DYNAMIC_IS_RO
1407 for (i=0; app.dynv[i]; i+=2)
1408 if (app.dynv[i]==DT_DEBUG)
1409 app.dynv[i+1] = (size_t)&debug;
1412 /* The main program must be relocated LAST since it may contin
1413 * copy relocations which depend on libraries' relocations. */
1414 reloc_all(app.next);
1418 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1419 void *initial_tls = calloc(libc.tls_size, 1);
1421 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1422 argv[0], libc.tls_size);
1425 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1429 size_t tmp_tls_size = libc.tls_size;
1430 pthread_t self = __pthread_self();
1431 /* Temporarily set the tls size to the full size of
1432 * builtin_tls so that __copy_tls will use the same layout
1433 * as it did for before. Then check, just to be safe. */
1434 libc.tls_size = sizeof builtin_tls;
1435 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1436 libc.tls_size = tmp_tls_size;
1438 static_tls_cnt = tls_cnt;
1440 if (ldso_fail) _exit(127);
1441 if (ldd_mode) _exit(0);
1443 /* Switch to runtime mode: any further failures in the dynamic
1444 * linker are a reportable failure rather than a fatal startup
1449 debug.bp = dl_debug_state;
1451 debug.base = ldso.base;
1455 __init_libc(envp, argv[0]);
1460 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1464 void *dlopen(const char *file, int mode)
1466 struct dso *volatile p, *orig_tail, *next;
1467 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1472 if (!file) return head;
1474 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1475 pthread_rwlock_wrlock(&lock);
1479 orig_tls_cnt = tls_cnt;
1480 orig_tls_offset = tls_offset;
1481 orig_tls_align = tls_align;
1483 noload = mode & RTLD_NOLOAD;
1486 if (setjmp(*rtld_fail)) {
1487 /* Clean up anything new that was (partially) loaded */
1488 if (p && p->deps) for (i=0; p->deps[i]; i++)
1489 if (p->deps[i]->global < 0)
1490 p->deps[i]->global = 0;
1491 for (p=orig_tail->next; p; p=next) {
1493 munmap(p->map, p->map_len);
1494 while (p->td_index) {
1495 void *tmp = p->td_index->next;
1499 if (p->rpath != p->rpath_orig)
1504 tls_cnt = orig_tls_cnt;
1505 tls_offset = orig_tls_offset;
1506 tls_align = orig_tls_align;
1511 } else p = load_library(file, head);
1515 "Library %s is not already loaded" :
1516 "Error loading shared library %s: %m",
1521 /* First load handling */
1524 if (p->deps) for (i=0; p->deps[i]; i++)
1525 if (!p->deps[i]->global)
1526 p->deps[i]->global = -1;
1527 if (!p->global) p->global = -1;
1529 if (p->deps) for (i=0; p->deps[i]; i++)
1530 if (p->deps[i]->global < 0)
1531 p->deps[i]->global = 0;
1532 if (p->global < 0) p->global = 0;
1535 if (mode & RTLD_GLOBAL) {
1536 if (p->deps) for (i=0; p->deps[i]; i++)
1537 p->deps[i]->global = 1;
1547 pthread_rwlock_unlock(&lock);
1548 if (p) do_init_fini(orig_tail);
1549 pthread_setcancelstate(cs, 0);
1553 static int invalid_dso_handle(void *h)
1556 for (p=head; p; p=p->next) if (h==p) return 0;
1557 error("Invalid library handle %p", (void *)h);
1561 void *__tls_get_addr(size_t *);
1563 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1566 uint32_t h = 0, gh = 0;
1568 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1569 if (p == RTLD_DEFAULT) {
1571 } else if (p == RTLD_NEXT) {
1572 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1576 struct symdef def = find_sym(p, s, 0);
1577 if (!def.sym) goto failed;
1578 if ((def.sym->st_info&0xf) == STT_TLS)
1579 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1580 return def.dso->base + def.sym->st_value;
1582 if (invalid_dso_handle(p))
1586 sym = gnu_lookup(s, gh, p);
1589 sym = sysv_lookup(s, h, p);
1591 if (sym && (sym->st_info&0xf) == STT_TLS)
1592 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1593 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1594 return p->base + sym->st_value;
1595 if (p->deps) for (i=0; p->deps[i]; i++) {
1596 if (p->deps[i]->ghashtab) {
1597 if (!gh) gh = gnu_hash(s);
1598 sym = gnu_lookup(s, gh, p->deps[i]);
1600 if (!h) h = sysv_hash(s);
1601 sym = sysv_lookup(s, h, p->deps[i]);
1603 if (sym && (sym->st_info&0xf) == STT_TLS)
1604 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1605 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1606 return p->deps[i]->base + sym->st_value;
1609 error("Symbol not found: %s", s);
1613 int __dladdr(const void *addr, Dl_info *info)
1623 pthread_rwlock_rdlock(&lock);
1624 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1625 pthread_rwlock_unlock(&lock);
1630 strings = p->strings;
1632 nsym = p->hashtab[1];
1636 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1637 sym += p->ghashtab[1];
1638 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1639 if (buckets[i] > nsym)
1643 nsym -= p->ghashtab[1];
1644 hashval = buckets + p->ghashtab[0] + nsym;
1646 while (!(*hashval++ & 1));
1650 for (; nsym; nsym--, sym++) {
1652 && (1<<(sym->st_info&0xf) & OK_TYPES)
1653 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1654 void *symaddr = p->base + sym->st_value;
1655 if (symaddr > addr || symaddr < best)
1658 bestname = strings + sym->st_name;
1659 if (addr == symaddr)
1664 if (!best) return 0;
1666 info->dli_fname = p->name;
1667 info->dli_fbase = p->base;
1668 info->dli_sname = bestname;
1669 info->dli_saddr = best;
1674 __attribute__((__visibility__("hidden")))
1675 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1678 pthread_rwlock_rdlock(&lock);
1679 res = do_dlsym(p, s, ra);
1680 pthread_rwlock_unlock(&lock);
1684 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1686 struct dso *current;
1687 struct dl_phdr_info info;
1689 for(current = head; current;) {
1690 info.dlpi_addr = (uintptr_t)current->base;
1691 info.dlpi_name = current->name;
1692 info.dlpi_phdr = current->phdr;
1693 info.dlpi_phnum = current->phnum;
1694 info.dlpi_adds = gencnt;
1696 info.dlpi_tls_modid = current->tls_id;
1697 info.dlpi_tls_data = current->tls_image;
1699 ret = (callback)(&info, sizeof (info), data);
1701 if (ret != 0) break;
1703 pthread_rwlock_rdlock(&lock);
1704 current = current->next;
1705 pthread_rwlock_unlock(&lock);
1710 static int invalid_dso_handle(void *h)
1712 error("Invalid library handle %p", (void *)h);
1715 void *dlopen(const char *file, int mode)
1717 error("Dynamic loading not supported");
1720 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1722 error("Symbol not found: %s", s);
1725 int __dladdr (const void *addr, Dl_info *info)
1731 int __dlinfo(void *dso, int req, void *res)
1733 if (invalid_dso_handle(dso)) return -1;
1734 if (req != RTLD_DI_LINKMAP) {
1735 error("Unsupported request %d", req);
1738 *(struct link_map **)res = dso;
1744 pthread_t self = __pthread_self();
1745 if (!self->dlerror_flag) return 0;
1746 self->dlerror_flag = 0;
1747 char *s = self->dlerror_buf;
1748 if (s == (void *)-1)
1749 return "Dynamic linker failed to allocate memory for error message";
1754 int dlclose(void *p)
1756 return invalid_dso_handle(p);
1759 void __dl_thread_cleanup(void)
1761 pthread_t self = __pthread_self();
1762 if (self->dlerror_buf != (void *)-1)
1763 free(self->dlerror_buf);
1766 static void error(const char *fmt, ...)
1772 vdprintf(2, fmt, ap);
1779 pthread_t self = __pthread_self();
1780 if (self->dlerror_buf != (void *)-1)
1781 free(self->dlerror_buf);
1782 size_t len = vsnprintf(0, 0, fmt, ap);
1784 char *buf = malloc(len+1);
1787 vsnprintf(buf, len+1, fmt, ap);
1792 self->dlerror_buf = buf;
1793 self->dlerror_flag = 1;