20 #include "pthread_impl.h"
23 #include "malloc_impl.h"
25 static void error(const char *, ...);
27 #define MAXP2(a,b) (-(-(a)&-(b)))
28 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
40 struct td_index *next;
45 struct fdpic_loadmap *loadmap;
51 struct dso *next, *prev;
61 struct dso *syms_next, *lazy_next;
62 size_t *lazy, lazy_cnt;
70 struct dso **deps, *needed_by;
71 char *rpath_orig, *rpath;
72 struct tls_module tls;
74 size_t relro_start, relro_end;
76 unsigned char *new_tls;
77 volatile int new_dtv_idx, new_tls_idx;
78 struct td_index *td_index;
79 struct dso *fini_next;
84 struct fdpic_loadmap *loadmap;
99 static struct builtin_tls {
104 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
106 #define ADDEND_LIMIT 4096
107 static size_t *saved_addends, *apply_addends_to;
109 static struct dso ldso;
110 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
111 static char *env_path, *sys_path;
112 static unsigned long long gencnt;
115 static int ldso_fail;
117 static jmp_buf *rtld_fail;
118 static pthread_rwlock_t lock;
119 static struct debug debug;
120 static struct tls_module *tls_tail;
121 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
122 static size_t static_tls_cnt;
123 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
124 static struct fdpic_loadmap *app_loadmap;
125 static struct fdpic_dummy_loadmap app_dummy_loadmap;
126 static struct dso *const nodeps_dummy;
128 struct debug *_dl_debug_addr = &debug;
130 extern hidden int __malloc_replaced;
132 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
134 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
136 weak_alias(__init_array_start, __init_array_end);
137 weak_alias(__fini_array_start, __fini_array_end);
139 static int dl_strcmp(const char *l, const char *r)
141 for (; *l==*r && *l; l++, r++);
142 return *(unsigned char *)l - *(unsigned char *)r;
144 #define strcmp(l,r) dl_strcmp(l,r)
146 /* Compute load address for a virtual address in a given dso. */
148 static void *laddr(const struct dso *p, size_t v)
151 if (!p->loadmap) return p->base + v;
152 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
153 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
155 static void *laddr_pg(const struct dso *p, size_t v)
158 size_t pgsz = PAGE_SIZE;
159 if (!p->loadmap) return p->base + v;
161 size_t a = p->loadmap->segs[j].p_vaddr;
162 size_t b = a + p->loadmap->segs[j].p_memsz;
168 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
170 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
171 laddr(p, v), (p)->got })
173 #define laddr(p, v) (void *)((p)->base + (v))
174 #define laddr_pg(p, v) laddr(p, v)
175 #define fpaddr(p, v) ((void (*)())laddr(p, v))
178 static void decode_vec(size_t *v, size_t *a, size_t cnt)
181 for (i=0; i<cnt; i++) a[i] = 0;
182 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
188 static int search_vec(size_t *v, size_t *r, size_t key)
190 for (; v[0]!=key; v+=2)
196 static uint32_t sysv_hash(const char *s0)
198 const unsigned char *s = (void *)s0;
204 return h & 0xfffffff;
207 static uint32_t gnu_hash(const char *s0)
209 const unsigned char *s = (void *)s0;
210 uint_fast32_t h = 5381;
216 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
219 Sym *syms = dso->syms;
220 Elf_Symndx *hashtab = dso->hashtab;
221 char *strings = dso->strings;
222 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
223 if ((!dso->versym || dso->versym[i] >= 0)
224 && (!strcmp(s, strings+syms[i].st_name)))
230 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
232 uint32_t nbuckets = hashtab[0];
233 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
234 uint32_t i = buckets[h1 % nbuckets];
238 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
240 for (h1 |= 1; ; i++) {
241 uint32_t h2 = *hashval++;
242 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
243 && !strcmp(s, dso->strings + dso->syms[i].st_name))
251 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
253 const size_t *bloomwords = (const void *)(hashtab+4);
254 size_t f = bloomwords[fofs & (hashtab[2]-1)];
255 if (!(f & fmask)) return 0;
257 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
258 if (!(f & 1)) return 0;
260 return gnu_lookup(h1, hashtab, dso, s);
263 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
264 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
266 #ifndef ARCH_SYM_REJECT_UND
267 #define ARCH_SYM_REJECT_UND(s) 0
270 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
272 uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
273 size_t ghm = 1ul << gh % (8*sizeof(size_t));
274 struct symdef def = {0};
275 for (; dso; dso=dso->syms_next) {
277 if ((ght = dso->ghashtab)) {
278 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
280 if (!h) h = sysv_hash(s);
281 sym = sysv_lookup(s, h, dso);
285 if (need_def || (sym->st_info&0xf) == STT_TLS
286 || ARCH_SYM_REJECT_UND(sym))
289 if ((sym->st_info&0xf) != STT_TLS)
291 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
292 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
300 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
302 unsigned char *base = dso->base;
303 Sym *syms = dso->syms;
304 char *strings = dso->strings;
315 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
318 /* Only ldso's REL table needs addend saving/reuse. */
319 if (rel == apply_addends_to)
324 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
325 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
326 type = R_TYPE(rel[1]);
327 if (type == REL_NONE) continue;
328 reloc_addr = laddr(dso, rel[0]);
332 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
334 } else if (reuse_addends) {
335 /* Save original addend in stage 2 where the dso
336 * chain consists of just ldso; otherwise read back
337 * saved addend since the inline one was clobbered. */
339 saved_addends[save_slot] = *reloc_addr;
340 addend = saved_addends[save_slot++];
342 addend = *reloc_addr;
345 sym_index = R_SYM(rel[1]);
347 sym = syms + sym_index;
348 name = strings + sym->st_name;
349 ctx = type==REL_COPY ? head->syms_next : head;
350 def = (sym->st_info&0xf) == STT_SECTION
351 ? (struct symdef){ .dso = dso, .sym = sym }
352 : find_sym(ctx, name, type==REL_PLT);
353 if (!def.sym && (sym->st_shndx != SHN_UNDEF
354 || sym->st_info>>4 != STB_WEAK)) {
355 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
356 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
357 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
358 dso->lazy[3*dso->lazy_cnt+2] = addend;
362 error("Error relocating %s: %s: symbol not found",
364 if (runtime) longjmp(*rtld_fail, 1);
373 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
374 tls_val = def.sym ? def.sym->st_value : 0;
376 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
377 && runtime && def.dso->tls_id > static_tls_cnt) {
378 error("Error relocating %s: %s: initial-exec TLS "
379 "resolves to dynamic definition in %s",
380 dso->name, name, def.dso->name);
381 longjmp(*rtld_fail, 1);
388 addend -= (size_t)reloc_addr;
392 *reloc_addr = sym_val + addend;
395 *reloc_addr = (size_t)base + addend;
398 if (sym) *reloc_addr = sym_val + addend;
399 else *reloc_addr = (size_t)base + addend;
402 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
405 *(uint32_t *)reloc_addr = sym_val + addend
406 - (size_t)reloc_addr;
409 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
410 + (def.sym - def.dso->syms)) : 0;
412 case REL_FUNCDESC_VAL:
413 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
414 else *reloc_addr = sym_val;
415 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
418 *reloc_addr = def.dso->tls_id;
421 *reloc_addr = tls_val + addend - DTP_OFFSET;
425 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
429 *reloc_addr = tls_val - def.dso->tls.offset + addend;
432 *reloc_addr = def.dso->tls.offset - tls_val + addend;
436 if (stride<3) addend = reloc_addr[1];
437 if (runtime && def.dso->tls_id > static_tls_cnt) {
438 struct td_index *new = malloc(sizeof *new);
441 "Error relocating %s: cannot allocate TLSDESC for %s",
442 dso->name, sym ? name : "(local)" );
443 longjmp(*rtld_fail, 1);
445 new->next = dso->td_index;
447 new->args[0] = def.dso->tls_id;
448 new->args[1] = tls_val + addend - DTP_OFFSET;
449 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
450 reloc_addr[1] = (size_t)new;
452 reloc_addr[0] = (size_t)__tlsdesc_static;
454 reloc_addr[1] = tls_val + def.dso->tls.offset
457 reloc_addr[1] = tls_val - def.dso->tls.offset
461 #ifdef TLSDESC_BACKWARDS
462 /* Some archs (32-bit ARM at least) invert the order of
463 * the descriptor members. Fix them up here. */
464 size_t tmp = reloc_addr[0];
465 reloc_addr[0] = reloc_addr[1];
470 error("Error relocating %s: unsupported relocation type %d",
472 if (runtime) longjmp(*rtld_fail, 1);
478 static void redo_lazy_relocs()
480 struct dso *p = lazy_head, *next;
484 size_t size = p->lazy_cnt*3*sizeof(size_t);
486 do_relocs(p, p->lazy, size, 3);
488 p->lazy_next = lazy_head;
498 /* A huge hack: to make up for the wastefulness of shared libraries
499 * needing at least a page of dirty memory even if they have no global
500 * data, we reclaim the gaps at the beginning and end of writable maps
501 * and "donate" them to the heap. */
503 static void reclaim(struct dso *dso, size_t start, size_t end)
505 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
506 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
507 if (start >= end) return;
508 char *base = laddr_pg(dso, start);
509 __malloc_donate(base, base+(end-start));
512 static void reclaim_gaps(struct dso *dso)
514 Phdr *ph = dso->phdr;
515 size_t phcnt = dso->phnum;
517 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
518 if (ph->p_type!=PT_LOAD) continue;
519 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
520 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
521 reclaim(dso, ph->p_vaddr+ph->p_memsz,
522 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
526 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
528 static int no_map_fixed;
531 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
532 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
536 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
537 if (flags & MAP_ANONYMOUS) {
542 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
543 for (q=p; n; q+=r, off+=r, n-=r) {
545 if (r < 0 && errno != EINTR) return MAP_FAILED;
554 static void unmap_library(struct dso *dso)
558 for (i=0; i<dso->loadmap->nsegs; i++) {
559 if (!dso->loadmap->segs[i].p_memsz)
561 munmap((void *)dso->loadmap->segs[i].addr,
562 dso->loadmap->segs[i].p_memsz);
565 } else if (dso->map && dso->map_len) {
566 munmap(dso->map, dso->map_len);
570 static void *map_library(int fd, struct dso *dso)
572 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
573 void *allocated_buf=0;
575 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
576 size_t this_min, this_max;
582 unsigned char *map=MAP_FAILED, *base;
587 ssize_t l = read(fd, buf, sizeof buf);
590 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
592 phsize = eh->e_phentsize * eh->e_phnum;
593 if (phsize > sizeof buf - sizeof *eh) {
594 allocated_buf = malloc(phsize);
595 if (!allocated_buf) return 0;
596 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
597 if (l < 0) goto error;
598 if (l != phsize) goto noexec;
599 ph = ph0 = allocated_buf;
600 } else if (eh->e_phoff + phsize > l) {
601 l = pread(fd, buf+1, phsize, eh->e_phoff);
602 if (l < 0) goto error;
603 if (l != phsize) goto noexec;
604 ph = ph0 = (void *)(buf + 1);
606 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
608 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
609 if (ph->p_type == PT_DYNAMIC) {
611 } else if (ph->p_type == PT_TLS) {
612 tls_image = ph->p_vaddr;
613 dso->tls.align = ph->p_align;
614 dso->tls.len = ph->p_filesz;
615 dso->tls.size = ph->p_memsz;
616 } else if (ph->p_type == PT_GNU_RELRO) {
617 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
618 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
619 } else if (ph->p_type == PT_GNU_STACK) {
620 if (!runtime && ph->p_memsz > __default_stacksize) {
621 __default_stacksize =
622 ph->p_memsz < DEFAULT_STACK_MAX ?
623 ph->p_memsz : DEFAULT_STACK_MAX;
626 if (ph->p_type != PT_LOAD) continue;
628 if (ph->p_vaddr < addr_min) {
629 addr_min = ph->p_vaddr;
630 off_start = ph->p_offset;
631 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
632 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
633 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
635 if (ph->p_vaddr+ph->p_memsz > addr_max) {
636 addr_max = ph->p_vaddr+ph->p_memsz;
639 if (!dyn) goto noexec;
640 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
641 dso->loadmap = calloc(1, sizeof *dso->loadmap
642 + nsegs * sizeof *dso->loadmap->segs);
643 if (!dso->loadmap) goto error;
644 dso->loadmap->nsegs = nsegs;
645 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
646 if (ph->p_type != PT_LOAD) continue;
647 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
648 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
649 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
650 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
652 fd, ph->p_offset & -PAGE_SIZE);
653 if (map == MAP_FAILED) {
657 dso->loadmap->segs[i].addr = (size_t)map +
658 (ph->p_vaddr & PAGE_SIZE-1);
659 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
660 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
662 if (prot & PROT_WRITE) {
663 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
665 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
666 size_t pgend = brk + ph->p_memsz - ph->p_filesz
667 + PAGE_SIZE-1 & -PAGE_SIZE;
668 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
670 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
671 -1, off_start) == MAP_FAILED)
673 memset(map + brk, 0, pgbrk-brk);
676 map = (void *)dso->loadmap->segs[0].addr;
680 addr_max += PAGE_SIZE-1;
681 addr_max &= -PAGE_SIZE;
682 addr_min &= -PAGE_SIZE;
683 off_start &= -PAGE_SIZE;
684 map_len = addr_max - addr_min + off_start;
685 /* The first time, we map too much, possibly even more than
686 * the length of the file. This is okay because we will not
687 * use the invalid part; we just need to reserve the right
688 * amount of virtual address space to map over later. */
689 map = DL_NOMMU_SUPPORT
690 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
691 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
692 : mmap((void *)addr_min, map_len, prot,
693 MAP_PRIVATE, fd, off_start);
694 if (map==MAP_FAILED) goto error;
696 dso->map_len = map_len;
697 /* If the loaded file is not relocatable and the requested address is
698 * not available, then the load operation must fail. */
699 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
703 base = map - addr_min;
706 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
707 if (ph->p_type != PT_LOAD) continue;
708 /* Check if the programs headers are in this load segment, and
709 * if so, record the address for use by dl_iterate_phdr. */
710 if (!dso->phdr && eh->e_phoff >= ph->p_offset
711 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
712 dso->phdr = (void *)(base + ph->p_vaddr
713 + (eh->e_phoff-ph->p_offset));
714 dso->phnum = eh->e_phnum;
715 dso->phentsize = eh->e_phentsize;
717 this_min = ph->p_vaddr & -PAGE_SIZE;
718 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
719 off_start = ph->p_offset & -PAGE_SIZE;
720 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
721 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
722 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
723 /* Reuse the existing mapping for the lowest-address LOAD */
724 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
725 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
727 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
728 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
729 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
730 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
731 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)
735 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
736 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
737 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
744 dso->dynv = laddr(dso, dyn);
745 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
751 if (map!=MAP_FAILED) unmap_library(dso);
756 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
761 s += strspn(s, ":\n");
762 l = strcspn(s, ":\n");
763 if (l-1 >= INT_MAX) return -1;
764 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
765 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
773 /* Any negative value but -1 will inhibit
774 * futher path search. */
782 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
785 const char *s, *t, *origin;
787 if (p->rpath || !p->rpath_orig) return 0;
788 if (!strchr(p->rpath_orig, '$')) {
789 p->rpath = p->rpath_orig;
794 while ((t=strchr(s, '$'))) {
795 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
800 if (n > SSIZE_MAX/PATH_MAX) return 0;
802 if (p->kernel_mapped) {
803 /* $ORIGIN searches cannot be performed for the main program
804 * when it is suid/sgid/AT_SECURE. This is because the
805 * pathname is under the control of the caller of execve.
806 * For libraries, however, $ORIGIN can be processed safely
807 * since the library's pathname came from a trusted source
808 * (either system paths or a call to dlopen). */
811 l = readlink("/proc/self/exe", buf, buf_size);
812 if (l == -1) switch (errno) {
827 t = strrchr(origin, '/');
831 /* Normally p->name will always be an absolute or relative
832 * pathname containing at least one '/' character, but in the
833 * case where ldso was invoked as a command to execute a
834 * program in the working directory, app.name may not. Fix. */
838 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
839 if (libc.secure && *origin != '/')
841 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
842 if (!p->rpath) return -1;
846 while ((t=strchr(s, '$'))) {
849 memcpy(d, origin, l);
851 /* It was determined previously that the '$' is followed
852 * either by "ORIGIN" or "{ORIGIN}". */
853 s = t + 7 + 2*(t[1]=='{');
859 static void decode_dyn(struct dso *p)
862 decode_vec(p->dynv, dyn, DYN_CNT);
863 p->syms = laddr(p, dyn[DT_SYMTAB]);
864 p->strings = laddr(p, dyn[DT_STRTAB]);
865 if (dyn[0]&(1<<DT_HASH))
866 p->hashtab = laddr(p, dyn[DT_HASH]);
867 if (dyn[0]&(1<<DT_RPATH))
868 p->rpath_orig = p->strings + dyn[DT_RPATH];
869 if (dyn[0]&(1<<DT_RUNPATH))
870 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
871 if (dyn[0]&(1<<DT_PLTGOT))
872 p->got = laddr(p, dyn[DT_PLTGOT]);
873 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
874 p->ghashtab = laddr(p, *dyn);
875 if (search_vec(p->dynv, dyn, DT_VERSYM))
876 p->versym = laddr(p, *dyn);
879 static size_t count_syms(struct dso *p)
881 if (p->hashtab) return p->hashtab[1];
884 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
886 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
887 if (buckets[i] > nsym)
891 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
893 while (!(*hashval++ & 1));
898 static void *dl_mmap(size_t n)
901 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
903 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
905 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
907 return p == MAP_FAILED ? 0 : p;
910 static void makefuncdescs(struct dso *p)
912 static int self_done;
913 size_t nsym = count_syms(p);
914 size_t i, size = nsym * sizeof(*p->funcdescs);
917 p->funcdescs = dl_mmap(size);
920 p->funcdescs = malloc(size);
923 if (!runtime) a_crash();
924 error("Error allocating function descriptors for %s", p->name);
925 longjmp(*rtld_fail, 1);
927 for (i=0; i<nsym; i++) {
928 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
929 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
930 p->funcdescs[i].got = p->got;
932 p->funcdescs[i].addr = 0;
933 p->funcdescs[i].got = 0;
938 static struct dso *load_library(const char *name, struct dso *needed_by)
940 char buf[2*NAME_MAX+2];
941 const char *pathname;
943 struct dso *p, temp_dso = {0};
955 /* Catch and block attempts to reload the implementation itself */
956 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
957 static const char reserved[] =
958 "c.pthread.rt.m.dl.util.xnet.";
959 const char *rp, *next;
960 for (rp=reserved; *rp; rp=next) {
961 next = strchr(rp, '.') + 1;
962 if (strncmp(name+3, rp, next-rp) == 0)
967 /* Track which names have been resolved
968 * and only report each one once. */
969 static unsigned reported;
970 unsigned mask = 1U<<(rp-reserved);
971 if (!(reported & mask)) {
973 dprintf(1, "\t%s => %s (%p)\n",
981 if (!strcmp(name, ldso.name)) is_self = 1;
990 if (strchr(name, '/')) {
992 fd = open(name, O_RDONLY|O_CLOEXEC);
994 /* Search for the name to see if it's already loaded */
995 for (p=head->next; p; p=p->next) {
996 if (p->shortname && !strcmp(p->shortname, name)) {
1000 if (strlen(name) > NAME_MAX) return 0;
1002 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1003 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1004 if (fixup_rpath(p, buf, sizeof buf) < 0)
1005 fd = -2; /* Inhibit further search. */
1007 fd = path_open(name, p->rpath, buf, sizeof buf);
1013 if (ldso.name[0]=='/') {
1015 for (s=t=z=ldso.name; *s; s++)
1016 if (*s=='/') z=t, t=s;
1017 prefix_len = z-ldso.name;
1018 if (prefix_len < PATH_MAX)
1025 char etc_ldso_path[prefix_len + 1
1026 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1027 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1028 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1029 (int)prefix_len, prefix);
1030 FILE *f = fopen(etc_ldso_path, "rbe");
1032 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1037 } else if (errno != ENOENT) {
1041 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1042 fd = path_open(name, sys_path, buf, sizeof buf);
1046 if (fd < 0) return 0;
1047 if (fstat(fd, &st) < 0) {
1051 for (p=head->next; p; p=p->next) {
1052 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1053 /* If this library was previously loaded with a
1054 * pathname but a search found the same inode,
1055 * setup its shortname so it can be found by name. */
1056 if (!p->shortname && pathname != name)
1057 p->shortname = strrchr(p->name, '/')+1;
1062 map = noload ? 0 : map_library(fd, &temp_dso);
1066 /* Avoid the danger of getting two versions of libc mapped into the
1067 * same process when an absolute pathname was used. The symbols
1068 * checked are chosen to catch both musl and glibc, and to avoid
1069 * false positives from interposition-hack libraries. */
1070 decode_dyn(&temp_dso);
1071 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1072 find_sym(&temp_dso, "stdin", 1).sym) {
1073 unmap_library(&temp_dso);
1074 return load_library("libc.so", needed_by);
1076 /* Past this point, if we haven't reached runtime yet, ldso has
1077 * committed either to use the mapped library or to abort execution.
1078 * Unmapping is not possible, so we can safely reclaim gaps. */
1079 if (!runtime) reclaim_gaps(&temp_dso);
1081 /* Allocate storage for the new DSO. When there is TLS, this
1082 * storage must include a reservation for all pre-existing
1083 * threads to obtain copies of both the new TLS, and an
1084 * extended DTV capable of storing an additional slot for
1085 * the newly-loaded DSO. */
1086 alloc_size = sizeof *p + strlen(pathname) + 1;
1087 if (runtime && temp_dso.tls.image) {
1088 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1089 + sizeof(void *) * (tls_cnt+3);
1090 n_th = libc.threads_minus_1 + 1;
1091 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1092 else alloc_size += n_th * per_th;
1094 p = calloc(1, alloc_size);
1096 unmap_library(&temp_dso);
1099 memcpy(p, &temp_dso, sizeof temp_dso);
1102 p->needed_by = needed_by;
1104 strcpy(p->name, pathname);
1105 /* Add a shortname only if name arg was not an explicit pathname. */
1106 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1108 p->tls_id = ++tls_cnt;
1109 tls_align = MAXP2(tls_align, p->tls.align);
1111 p->tls.offset = tls_offset + ( (tls_align-1) &
1112 -(tls_offset + (uintptr_t)p->tls.image) );
1113 tls_offset += p->tls.size;
1115 tls_offset += p->tls.size + p->tls.align - 1;
1116 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1118 p->tls.offset = tls_offset;
1120 p->new_dtv = (void *)(-sizeof(size_t) &
1121 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1122 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1123 if (tls_tail) tls_tail->next = &p->tls;
1124 else libc.tls_head = &p->tls;
1132 if (DL_FDPIC) makefuncdescs(p);
1134 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1139 static void load_deps(struct dso *p)
1142 struct dso ***deps = &p->deps, **tmp, *dep;
1143 for (; p; p=p->next) {
1144 for (i=0; p->dynv[i]; i+=2) {
1145 if (p->dynv[i] != DT_NEEDED) continue;
1146 dep = load_library(p->strings + p->dynv[i+1], p);
1148 error("Error loading shared library %s: %m (needed by %s)",
1149 p->strings + p->dynv[i+1], p->name);
1150 if (runtime) longjmp(*rtld_fail, 1);
1154 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1155 if (!tmp) longjmp(*rtld_fail, 1);
1162 if (!*deps) *deps = (struct dso **)&nodeps_dummy;
1165 static void load_preload(char *s)
1169 for (z=s; *z; s=z) {
1170 for ( ; *s && (isspace(*s) || *s==':'); s++);
1171 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1179 static void add_syms(struct dso *p)
1181 if (!p->syms_next && syms_tail != p) {
1182 syms_tail->syms_next = p;
1187 static void revert_syms(struct dso *old_tail)
1189 struct dso *p, *next;
1190 /* Chop off the tail of the list of dsos that participate in
1191 * the global symbol table, reverting them to RTLD_LOCAL. */
1192 for (p=old_tail; p; p=next) {
1193 next = p->syms_next;
1196 syms_tail = old_tail;
1199 static void do_mips_relocs(struct dso *p, size_t *got)
1201 size_t i, j, rel[2];
1202 unsigned char *base = p->base;
1203 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1207 while (i--) *got++ += (size_t)base;
1209 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1210 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1211 Sym *sym = p->syms + j;
1212 rel[0] = (unsigned char *)got - base;
1213 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1214 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1215 do_relocs(p, rel, sizeof rel, 2);
1219 static void reloc_all(struct dso *p)
1221 size_t dyn[DYN_CNT];
1222 for (; p; p=p->next) {
1223 if (p->relocated) continue;
1224 decode_vec(p->dynv, dyn, DYN_CNT);
1225 if (NEED_MIPS_GOT_RELOCS)
1226 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1227 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1228 2+(dyn[DT_PLTREL]==DT_RELA));
1229 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1230 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1232 if (head != &ldso && p->relro_start != p->relro_end &&
1233 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1234 && errno != ENOSYS) {
1235 error("Error relocating %s: RELRO protection failed: %m",
1237 if (runtime) longjmp(*rtld_fail, 1);
1244 static void kernel_mapped_dso(struct dso *p)
1246 size_t min_addr = -1, max_addr = 0, cnt;
1248 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1249 if (ph->p_type == PT_DYNAMIC) {
1250 p->dynv = laddr(p, ph->p_vaddr);
1251 } else if (ph->p_type == PT_GNU_RELRO) {
1252 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1253 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1254 } else if (ph->p_type == PT_GNU_STACK) {
1255 if (!runtime && ph->p_memsz > __default_stacksize) {
1256 __default_stacksize =
1257 ph->p_memsz < DEFAULT_STACK_MAX ?
1258 ph->p_memsz : DEFAULT_STACK_MAX;
1261 if (ph->p_type != PT_LOAD) continue;
1262 if (ph->p_vaddr < min_addr)
1263 min_addr = ph->p_vaddr;
1264 if (ph->p_vaddr+ph->p_memsz > max_addr)
1265 max_addr = ph->p_vaddr+ph->p_memsz;
1267 min_addr &= -PAGE_SIZE;
1268 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1269 p->map = p->base + min_addr;
1270 p->map_len = max_addr - min_addr;
1271 p->kernel_mapped = 1;
1274 void __libc_exit_fini()
1277 size_t dyn[DYN_CNT];
1278 for (p=fini_head; p; p=p->fini_next) {
1279 if (!p->constructed) continue;
1280 decode_vec(p->dynv, dyn, DYN_CNT);
1281 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1282 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1283 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1284 while (n--) ((void (*)(void))*--fn)();
1286 #ifndef NO_LEGACY_INITFINI
1287 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1288 fpaddr(p, dyn[DT_FINI])();
1293 static void do_init_fini(struct dso *p)
1295 size_t dyn[DYN_CNT];
1296 int need_locking = libc.threads_minus_1;
1297 /* Allow recursive calls that arise when a library calls
1298 * dlopen from one of its constructors, but block any
1299 * other threads until all ctors have finished. */
1300 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1301 for (; p; p=p->prev) {
1302 if (p->constructed) continue;
1304 decode_vec(p->dynv, dyn, DYN_CNT);
1305 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1306 p->fini_next = fini_head;
1309 #ifndef NO_LEGACY_INITFINI
1310 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1311 fpaddr(p, dyn[DT_INIT])();
1313 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1314 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1315 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1316 while (n--) ((void (*)(void))*fn++)();
1318 if (!need_locking && libc.threads_minus_1) {
1320 pthread_mutex_lock(&init_fini_lock);
1323 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1326 void __libc_start_init(void)
1331 static void dl_debug_state(void)
1335 weak_alias(dl_debug_state, _dl_debug_state);
1337 void __init_tls(size_t *auxv)
1341 hidden void *__tls_get_new(tls_mod_off_t *v)
1343 pthread_t self = __pthread_self();
1345 /* Block signals to make accessing new TLS async-signal-safe */
1347 __block_all_sigs(&set);
1348 if (v[0] <= self->dtv[0]) {
1349 __restore_sigs(&set);
1350 return (void *)(self->dtv[v[0]] + v[1]);
1353 /* This is safe without any locks held because, if the caller
1354 * is able to request the Nth entry of the DTV, the DSO list
1355 * must be valid at least that far out and it was synchronized
1356 * at program startup or by an already-completed call to dlopen. */
1358 for (p=head; p->tls_id != v[0]; p=p->next);
1360 /* Get new DTV space from new DSO */
1361 uintptr_t *newdtv = p->new_dtv +
1362 (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
1363 memcpy(newdtv, self->dtv, (self->dtv[0]+1) * sizeof(uintptr_t));
1365 self->dtv = self->dtv_copy = newdtv;
1367 /* Get new TLS memory from all new DSOs up to the requested one */
1369 for (p=head; ; p=p->next) {
1370 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1371 mem = p->new_tls + (p->tls.size + p->tls.align)
1372 * a_fetch_add(&p->new_tls_idx,1);
1373 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1375 self->dtv[p->tls_id] = (uintptr_t)mem + DTP_OFFSET;
1376 memcpy(mem, p->tls.image, p->tls.len);
1377 if (p->tls_id == v[0]) break;
1379 __restore_sigs(&set);
1380 return mem + v[1] + DTP_OFFSET;
1383 static void update_tls_size()
1385 libc.tls_cnt = tls_cnt;
1386 libc.tls_align = tls_align;
1387 libc.tls_size = ALIGN(
1388 (1+tls_cnt) * sizeof(void *) +
1390 sizeof(struct pthread) +
1395 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1396 * following stage 2 and stage 3 functions via primitive symbolic lookup
1397 * since it does not have access to their addresses to begin with. */
1399 /* Stage 2 of the dynamic linker is called after relative relocations
1400 * have been processed. It can make function calls to static functions
1401 * and access string literals and static data, but cannot use extern
1402 * symbols. Its job is to perform symbolic relocations on the dynamic
1403 * linker itself, but some of the relocations performed may need to be
1404 * replaced later due to copy relocations in the main program. */
1406 hidden void __dls2(unsigned char *base, size_t *sp)
1409 void *p1 = (void *)sp[-2];
1410 void *p2 = (void *)sp[-1];
1412 size_t *auxv, aux[AUX_CNT];
1413 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1414 decode_vec(auxv, aux, AUX_CNT);
1415 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1416 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1418 app_loadmap = p2 ? p1 : 0;
1419 ldso.loadmap = p2 ? p2 : p1;
1420 ldso.base = laddr(&ldso, 0);
1424 Ehdr *ehdr = (void *)ldso.base;
1425 ldso.name = ldso.shortname = "libc.so";
1426 ldso.phnum = ehdr->e_phnum;
1427 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1428 ldso.phentsize = ehdr->e_phentsize;
1429 kernel_mapped_dso(&ldso);
1432 if (DL_FDPIC) makefuncdescs(&ldso);
1434 /* Prepare storage for to save clobbered REL addends so they
1435 * can be reused in stage 3. There should be very few. If
1436 * something goes wrong and there are a huge number, abort
1437 * instead of risking stack overflow. */
1438 size_t dyn[DYN_CNT];
1439 decode_vec(ldso.dynv, dyn, DYN_CNT);
1440 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1441 size_t rel_size = dyn[DT_RELSZ];
1442 size_t symbolic_rel_cnt = 0;
1443 apply_addends_to = rel;
1444 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1445 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1446 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1447 size_t addends[symbolic_rel_cnt+1];
1448 saved_addends = addends;
1455 /* Call dynamic linker stage-3, __dls3, looking it up
1456 * symbolically as a barrier against moving the address
1457 * load across the above relocation processing. */
1458 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1459 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1460 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1463 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1464 * fully functional. Its job is to load (if not already loaded) and
1465 * process dependencies and relocations for the main application and
1466 * transfer control to its entry point. */
1468 _Noreturn void __dls3(size_t *sp)
1470 static struct dso app, vdso;
1471 size_t aux[AUX_CNT], *auxv;
1473 char *env_preload=0;
1474 char *replace_argv0=0;
1477 char **argv = (void *)(sp+1);
1478 char **argv_orig = argv;
1479 char **envp = argv+argc+1;
1481 /* Find aux vector just past environ[] and use it to initialize
1482 * global data that may be needed before we can make syscalls. */
1484 for (i=argc+1; argv[i]; i++);
1485 libc.auxv = auxv = (void *)(argv+i+1);
1486 decode_vec(auxv, aux, AUX_CNT);
1487 __hwcap = aux[AT_HWCAP];
1488 libc.page_size = aux[AT_PAGESZ];
1489 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1490 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1492 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1493 * use during dynamic linking. If possible it will also serve as the
1494 * thread pointer at runtime. */
1495 libc.tls_size = sizeof builtin_tls;
1496 libc.tls_align = tls_align;
1497 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1501 /* Only trust user/env if kernel says we're not suid/sgid */
1503 env_path = getenv("LD_LIBRARY_PATH");
1504 env_preload = getenv("LD_PRELOAD");
1507 /* If the main program was already loaded by the kernel,
1508 * AT_PHDR will point to some location other than the dynamic
1509 * linker's program headers. */
1510 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1511 size_t interp_off = 0;
1512 size_t tls_image = 0;
1513 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1514 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1515 app.phnum = aux[AT_PHNUM];
1516 app.phentsize = aux[AT_PHENT];
1517 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1518 if (phdr->p_type == PT_PHDR)
1519 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1520 else if (phdr->p_type == PT_INTERP)
1521 interp_off = (size_t)phdr->p_vaddr;
1522 else if (phdr->p_type == PT_TLS) {
1523 tls_image = phdr->p_vaddr;
1524 app.tls.len = phdr->p_filesz;
1525 app.tls.size = phdr->p_memsz;
1526 app.tls.align = phdr->p_align;
1529 if (DL_FDPIC) app.loadmap = app_loadmap;
1530 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1531 if (interp_off) ldso.name = laddr(&app, interp_off);
1532 if ((aux[0] & (1UL<<AT_EXECFN))
1533 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1534 app.name = (char *)aux[AT_EXECFN];
1537 kernel_mapped_dso(&app);
1540 char *ldname = argv[0];
1541 size_t l = strlen(ldname);
1542 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1544 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1545 char *opt = argv[0]+2;
1546 *argv++ = (void *)-1;
1549 } else if (!memcmp(opt, "list", 5)) {
1551 } else if (!memcmp(opt, "library-path", 12)) {
1552 if (opt[12]=='=') env_path = opt+13;
1553 else if (opt[12]) *argv = 0;
1554 else if (*argv) env_path = *argv++;
1555 } else if (!memcmp(opt, "preload", 7)) {
1556 if (opt[7]=='=') env_preload = opt+8;
1557 else if (opt[7]) *argv = 0;
1558 else if (*argv) env_preload = *argv++;
1559 } else if (!memcmp(opt, "argv0", 5)) {
1560 if (opt[5]=='=') replace_argv0 = opt+6;
1561 else if (opt[5]) *argv = 0;
1562 else if (*argv) replace_argv0 = *argv++;
1567 argv[-1] = (void *)(argc - (argv-argv_orig));
1569 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1571 "Dynamic Program Loader\n"
1572 "Usage: %s [options] [--] pathname%s\n",
1573 __libc_version, ldname,
1574 ldd_mode ? "" : " [args]");
1577 fd = open(argv[0], O_RDONLY);
1579 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1582 Ehdr *ehdr = (void *)map_library(fd, &app);
1584 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1590 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1591 /* Find the name that would have been used for the dynamic
1592 * linker had ldd not taken its place. */
1594 for (i=0; i<app.phnum; i++) {
1595 if (app.phdr[i].p_type == PT_INTERP)
1596 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1598 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1602 libc.tls_head = tls_tail = &app.tls;
1603 app.tls_id = tls_cnt = 1;
1605 app.tls.offset = GAP_ABOVE_TP;
1606 app.tls.offset += -GAP_ABOVE_TP & (app.tls.align-1);
1607 tls_offset = app.tls.offset + app.tls.size
1608 + ( -((uintptr_t)app.tls.image + app.tls.size)
1609 & (app.tls.align-1) );
1611 tls_offset = app.tls.offset = app.tls.size
1612 + ( -((uintptr_t)app.tls.image + app.tls.size)
1613 & (app.tls.align-1) );
1615 tls_align = MAXP2(tls_align, app.tls.align);
1619 makefuncdescs(&app);
1621 app.loadmap = (void *)&app_dummy_loadmap;
1622 app.loadmap->nsegs = 1;
1623 app.loadmap->segs[0].addr = (size_t)app.map;
1624 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1626 app.loadmap->segs[0].p_memsz = app.map_len;
1628 argv[-3] = (void *)app.loadmap;
1631 /* Initial dso chain consists only of the app. */
1632 head = tail = syms_tail = &app;
1634 /* Donate unused parts of app and library mapping to malloc */
1636 reclaim_gaps(&ldso);
1638 /* Load preload/needed libraries, add symbols to global namespace. */
1639 if (env_preload) load_preload(env_preload);
1641 for (struct dso *p=head; p; p=p->next)
1644 /* Attach to vdso, if provided by the kernel, last so that it does
1645 * not become part of the global namespace. */
1646 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1647 Ehdr *ehdr = (void *)vdso_base;
1648 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1649 vdso.phnum = ehdr->e_phnum;
1650 vdso.phentsize = ehdr->e_phentsize;
1651 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1652 if (phdr->p_type == PT_DYNAMIC)
1653 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1654 if (phdr->p_type == PT_LOAD)
1655 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1658 vdso.shortname = "linux-gate.so.1";
1666 for (i=0; app.dynv[i]; i+=2) {
1667 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1668 app.dynv[i+1] = (size_t)&debug;
1669 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1670 size_t *ptr = (size_t *) app.dynv[i+1];
1671 *ptr = (size_t)&debug;
1675 /* The main program must be relocated LAST since it may contin
1676 * copy relocations which depend on libraries' relocations. */
1677 reloc_all(app.next);
1681 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1682 void *initial_tls = calloc(libc.tls_size, 1);
1684 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1685 argv[0], libc.tls_size);
1688 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1692 size_t tmp_tls_size = libc.tls_size;
1693 pthread_t self = __pthread_self();
1694 /* Temporarily set the tls size to the full size of
1695 * builtin_tls so that __copy_tls will use the same layout
1696 * as it did for before. Then check, just to be safe. */
1697 libc.tls_size = sizeof builtin_tls;
1698 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1699 libc.tls_size = tmp_tls_size;
1701 static_tls_cnt = tls_cnt;
1703 if (ldso_fail) _exit(127);
1704 if (ldd_mode) _exit(0);
1706 /* Determine if malloc was interposed by a replacement implementation
1707 * so that calloc and the memalign family can harden against the
1708 * possibility of incomplete replacement. */
1709 if (find_sym(head, "malloc", 1).dso != &ldso)
1710 __malloc_replaced = 1;
1712 /* Switch to runtime mode: any further failures in the dynamic
1713 * linker are a reportable failure rather than a fatal startup
1718 debug.bp = dl_debug_state;
1720 debug.base = ldso.base;
1724 if (replace_argv0) argv[0] = replace_argv0;
1728 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1732 static void prepare_lazy(struct dso *p)
1734 size_t dyn[DYN_CNT], n, flags1=0;
1735 decode_vec(p->dynv, dyn, DYN_CNT);
1736 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1737 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1739 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1740 if (NEED_MIPS_GOT_RELOCS) {
1741 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1742 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1745 p->lazy = calloc(n, 3*sizeof(size_t));
1747 error("Error preparing lazy relocation for %s: %m", p->name);
1748 longjmp(*rtld_fail, 1);
1750 p->lazy_next = lazy_head;
1754 void *dlopen(const char *file, int mode)
1756 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1757 struct tls_module *orig_tls_tail;
1758 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1763 if (!file) return head;
1765 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1766 pthread_rwlock_wrlock(&lock);
1770 orig_tls_tail = tls_tail;
1771 orig_tls_cnt = tls_cnt;
1772 orig_tls_offset = tls_offset;
1773 orig_tls_align = tls_align;
1774 orig_lazy_head = lazy_head;
1775 orig_syms_tail = syms_tail;
1777 noload = mode & RTLD_NOLOAD;
1780 if (setjmp(*rtld_fail)) {
1781 /* Clean up anything new that was (partially) loaded */
1782 revert_syms(orig_syms_tail);
1783 for (p=orig_tail->next; p; p=next) {
1785 while (p->td_index) {
1786 void *tmp = p->td_index->next;
1791 if (p->rpath != p->rpath_orig)
1793 if (p->deps != &nodeps_dummy)
1798 if (!orig_tls_tail) libc.tls_head = 0;
1799 tls_tail = orig_tls_tail;
1800 if (tls_tail) tls_tail->next = 0;
1801 tls_cnt = orig_tls_cnt;
1802 tls_offset = orig_tls_offset;
1803 tls_align = orig_tls_align;
1804 lazy_head = orig_lazy_head;
1809 } else p = load_library(file, head);
1813 "Library %s is not already loaded" :
1814 "Error loading shared library %s: %m",
1819 /* First load handling */
1820 int first_load = !p->deps;
1823 if (!p->relocated && (mode & RTLD_LAZY)) {
1825 for (i=0; p->deps[i]; i++)
1826 if (!p->deps[i]->relocated)
1827 prepare_lazy(p->deps[i]);
1830 if (first_load || (mode & RTLD_GLOBAL)) {
1831 /* Make new symbols global, at least temporarily, so we can do
1832 * relocations. If not RTLD_GLOBAL, this is reverted below. */
1834 for (i=0; p->deps[i]; i++)
1835 add_syms(p->deps[i]);
1841 /* If RTLD_GLOBAL was not specified, undo any new additions
1842 * to the global symbol table. This is a nop if the library was
1843 * previously loaded and already global. */
1844 if (!(mode & RTLD_GLOBAL))
1845 revert_syms(orig_syms_tail);
1847 /* Processing of deferred lazy relocations must not happen until
1848 * the new libraries are committed; otherwise we could end up with
1849 * relocations resolved to symbol definitions that get removed. */
1858 pthread_rwlock_unlock(&lock);
1859 if (p) do_init_fini(orig_tail);
1860 pthread_setcancelstate(cs, 0);
1864 hidden int __dl_invalid_handle(void *h)
1867 for (p=head; p; p=p->next) if (h==p) return 0;
1868 error("Invalid library handle %p", (void *)h);
1872 static void *addr2dso(size_t a)
1876 if (DL_FDPIC) for (p=head; p; p=p->next) {
1878 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1881 for (p=head; p; p=p->next) {
1882 if (DL_FDPIC && p->loadmap) {
1883 for (i=0; i<p->loadmap->nsegs; i++) {
1884 if (a-p->loadmap->segs[i].p_vaddr
1885 < p->loadmap->segs[i].p_memsz)
1890 size_t phcnt = p->phnum;
1891 size_t entsz = p->phentsize;
1892 size_t base = (size_t)p->base;
1893 for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
1894 if (ph->p_type != PT_LOAD) continue;
1895 if (a-base-ph->p_vaddr < ph->p_memsz)
1898 if (a-(size_t)p->map < p->map_len)
1905 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1908 uint32_t h = 0, gh = 0, *ght;
1910 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1911 if (p == RTLD_DEFAULT) {
1913 } else if (p == RTLD_NEXT) {
1914 p = addr2dso((size_t)ra);
1918 struct symdef def = find_sym(p, s, 0);
1919 if (!def.sym) goto failed;
1920 if ((def.sym->st_info&0xf) == STT_TLS)
1921 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value});
1922 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1923 return def.dso->funcdescs + (def.sym - def.dso->syms);
1924 return laddr(def.dso, def.sym->st_value);
1926 if (__dl_invalid_handle(p))
1928 if ((ght = p->ghashtab)) {
1930 sym = gnu_lookup(gh, ght, p, s);
1933 sym = sysv_lookup(s, h, p);
1935 if (sym && (sym->st_info&0xf) == STT_TLS)
1936 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value});
1937 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1938 return p->funcdescs + (sym - p->syms);
1939 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1940 return laddr(p, sym->st_value);
1941 for (i=0; p->deps[i]; i++) {
1942 if ((ght = p->deps[i]->ghashtab)) {
1943 if (!gh) gh = gnu_hash(s);
1944 sym = gnu_lookup(gh, ght, p->deps[i], s);
1946 if (!h) h = sysv_hash(s);
1947 sym = sysv_lookup(s, h, p->deps[i]);
1949 if (sym && (sym->st_info&0xf) == STT_TLS)
1950 return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value});
1951 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1952 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1953 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1954 return laddr(p->deps[i], sym->st_value);
1957 error("Symbol not found: %s", s);
1961 int dladdr(const void *addr_arg, Dl_info *info)
1963 size_t addr = (size_t)addr_arg;
1969 size_t besterr = -1;
1971 pthread_rwlock_rdlock(&lock);
1973 pthread_rwlock_unlock(&lock);
1978 strings = p->strings;
1979 nsym = count_syms(p);
1982 size_t idx = (addr-(size_t)p->funcdescs)
1983 / sizeof(*p->funcdescs);
1984 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1985 best = (size_t)(p->funcdescs + idx);
1986 bestsym = sym + idx;
1991 if (!best) for (; nsym; nsym--, sym++) {
1993 && (1<<(sym->st_info&0xf) & OK_TYPES)
1994 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1995 size_t symaddr = (size_t)laddr(p, sym->st_value);
1996 if (symaddr > addr || symaddr <= best)
2000 besterr = addr - symaddr;
2001 if (addr == symaddr)
2006 if (bestsym && besterr > bestsym->st_size-1) {
2011 info->dli_fname = p->name;
2012 info->dli_fbase = p->map;
2015 info->dli_sname = 0;
2016 info->dli_saddr = 0;
2020 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2021 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2022 info->dli_sname = strings + bestsym->st_name;
2023 info->dli_saddr = (void *)best;
2028 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2031 pthread_rwlock_rdlock(&lock);
2032 res = do_dlsym(p, s, ra);
2033 pthread_rwlock_unlock(&lock);
2037 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2039 struct dso *current;
2040 struct dl_phdr_info info;
2042 for(current = head; current;) {
2043 info.dlpi_addr = (uintptr_t)current->base;
2044 info.dlpi_name = current->name;
2045 info.dlpi_phdr = current->phdr;
2046 info.dlpi_phnum = current->phnum;
2047 info.dlpi_adds = gencnt;
2049 info.dlpi_tls_modid = current->tls_id;
2050 info.dlpi_tls_data = current->tls.image;
2052 ret = (callback)(&info, sizeof (info), data);
2054 if (ret != 0) break;
2056 pthread_rwlock_rdlock(&lock);
2057 current = current->next;
2058 pthread_rwlock_unlock(&lock);
2063 static void error(const char *fmt, ...)
2068 vdprintf(2, fmt, ap);
2074 __dl_vseterr(fmt, ap);