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;
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
463 error("Error relocating %s: unsupported relocation type %d",
465 if (runtime) longjmp(*rtld_fail, 1);
471 static void redo_lazy_relocs()
473 struct dso *p = lazy_head, *next;
477 size_t size = p->lazy_cnt*3*sizeof(size_t);
479 do_relocs(p, p->lazy, size, 3);
481 p->lazy_next = lazy_head;
491 /* A huge hack: to make up for the wastefulness of shared libraries
492 * needing at least a page of dirty memory even if they have no global
493 * data, we reclaim the gaps at the beginning and end of writable maps
494 * and "donate" them to the heap. */
496 static void reclaim(struct dso *dso, size_t start, size_t end)
498 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
499 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
500 if (start >= end) return;
501 char *base = laddr_pg(dso, start);
502 __malloc_donate(base, base+(end-start));
505 static void reclaim_gaps(struct dso *dso)
507 Phdr *ph = dso->phdr;
508 size_t phcnt = dso->phnum;
510 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
511 if (ph->p_type!=PT_LOAD) continue;
512 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
513 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
514 reclaim(dso, ph->p_vaddr+ph->p_memsz,
515 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
519 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
521 static int no_map_fixed;
524 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
525 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
529 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
530 if (flags & MAP_ANONYMOUS) {
535 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
536 for (q=p; n; q+=r, off+=r, n-=r) {
538 if (r < 0 && errno != EINTR) return MAP_FAILED;
547 static void unmap_library(struct dso *dso)
551 for (i=0; i<dso->loadmap->nsegs; i++) {
552 if (!dso->loadmap->segs[i].p_memsz)
554 munmap((void *)dso->loadmap->segs[i].addr,
555 dso->loadmap->segs[i].p_memsz);
558 } else if (dso->map && dso->map_len) {
559 munmap(dso->map, dso->map_len);
563 static void *map_library(int fd, struct dso *dso)
565 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
566 void *allocated_buf=0;
568 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
569 size_t this_min, this_max;
575 unsigned char *map=MAP_FAILED, *base;
580 ssize_t l = read(fd, buf, sizeof buf);
583 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
585 phsize = eh->e_phentsize * eh->e_phnum;
586 if (phsize > sizeof buf - sizeof *eh) {
587 allocated_buf = malloc(phsize);
588 if (!allocated_buf) return 0;
589 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
590 if (l < 0) goto error;
591 if (l != phsize) goto noexec;
592 ph = ph0 = allocated_buf;
593 } else if (eh->e_phoff + phsize > l) {
594 l = pread(fd, buf+1, phsize, eh->e_phoff);
595 if (l < 0) goto error;
596 if (l != phsize) goto noexec;
597 ph = ph0 = (void *)(buf + 1);
599 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
601 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
602 if (ph->p_type == PT_DYNAMIC) {
604 } else if (ph->p_type == PT_TLS) {
605 tls_image = ph->p_vaddr;
606 dso->tls.align = ph->p_align;
607 dso->tls.len = ph->p_filesz;
608 dso->tls.size = ph->p_memsz;
609 } else if (ph->p_type == PT_GNU_RELRO) {
610 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
611 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
613 if (ph->p_type != PT_LOAD) continue;
615 if (ph->p_vaddr < addr_min) {
616 addr_min = ph->p_vaddr;
617 off_start = ph->p_offset;
618 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
619 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
620 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
622 if (ph->p_vaddr+ph->p_memsz > addr_max) {
623 addr_max = ph->p_vaddr+ph->p_memsz;
626 if (!dyn) goto noexec;
627 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
628 dso->loadmap = calloc(1, sizeof *dso->loadmap
629 + nsegs * sizeof *dso->loadmap->segs);
630 if (!dso->loadmap) goto error;
631 dso->loadmap->nsegs = nsegs;
632 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
633 if (ph->p_type != PT_LOAD) continue;
634 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
635 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
636 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
637 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
639 fd, ph->p_offset & -PAGE_SIZE);
640 if (map == MAP_FAILED) {
644 dso->loadmap->segs[i].addr = (size_t)map +
645 (ph->p_vaddr & PAGE_SIZE-1);
646 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
647 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
649 if (prot & PROT_WRITE) {
650 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
652 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
653 size_t pgend = brk + ph->p_memsz - ph->p_filesz
654 + PAGE_SIZE-1 & -PAGE_SIZE;
655 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
657 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
658 -1, off_start) == MAP_FAILED)
660 memset(map + brk, 0, pgbrk-brk);
663 map = (void *)dso->loadmap->segs[0].addr;
667 addr_max += PAGE_SIZE-1;
668 addr_max &= -PAGE_SIZE;
669 addr_min &= -PAGE_SIZE;
670 off_start &= -PAGE_SIZE;
671 map_len = addr_max - addr_min + off_start;
672 /* The first time, we map too much, possibly even more than
673 * the length of the file. This is okay because we will not
674 * use the invalid part; we just need to reserve the right
675 * amount of virtual address space to map over later. */
676 map = DL_NOMMU_SUPPORT
677 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
678 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
679 : mmap((void *)addr_min, map_len, prot,
680 MAP_PRIVATE, fd, off_start);
681 if (map==MAP_FAILED) goto error;
683 dso->map_len = map_len;
684 /* If the loaded file is not relocatable and the requested address is
685 * not available, then the load operation must fail. */
686 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
690 base = map - addr_min;
693 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
694 if (ph->p_type != PT_LOAD) continue;
695 /* Check if the programs headers are in this load segment, and
696 * if so, record the address for use by dl_iterate_phdr. */
697 if (!dso->phdr && eh->e_phoff >= ph->p_offset
698 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
699 dso->phdr = (void *)(base + ph->p_vaddr
700 + (eh->e_phoff-ph->p_offset));
701 dso->phnum = eh->e_phnum;
702 dso->phentsize = eh->e_phentsize;
704 this_min = ph->p_vaddr & -PAGE_SIZE;
705 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
706 off_start = ph->p_offset & -PAGE_SIZE;
707 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
708 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
709 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
710 /* Reuse the existing mapping for the lowest-address LOAD */
711 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
712 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
714 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
715 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
716 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
717 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
718 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)
722 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
723 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
724 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
731 dso->dynv = laddr(dso, dyn);
732 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
738 if (map!=MAP_FAILED) unmap_library(dso);
743 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
748 s += strspn(s, ":\n");
749 l = strcspn(s, ":\n");
750 if (l-1 >= INT_MAX) return -1;
751 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
752 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
760 /* Any negative value but -1 will inhibit
761 * futher path search. */
769 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
772 const char *s, *t, *origin;
774 if (p->rpath || !p->rpath_orig) return 0;
775 if (!strchr(p->rpath_orig, '$')) {
776 p->rpath = p->rpath_orig;
781 while ((t=strchr(s, '$'))) {
782 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
787 if (n > SSIZE_MAX/PATH_MAX) return 0;
789 if (p->kernel_mapped) {
790 /* $ORIGIN searches cannot be performed for the main program
791 * when it is suid/sgid/AT_SECURE. This is because the
792 * pathname is under the control of the caller of execve.
793 * For libraries, however, $ORIGIN can be processed safely
794 * since the library's pathname came from a trusted source
795 * (either system paths or a call to dlopen). */
798 l = readlink("/proc/self/exe", buf, buf_size);
799 if (l == -1) switch (errno) {
814 t = strrchr(origin, '/');
818 /* Normally p->name will always be an absolute or relative
819 * pathname containing at least one '/' character, but in the
820 * case where ldso was invoked as a command to execute a
821 * program in the working directory, app.name may not. Fix. */
825 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
826 if (libc.secure && *origin != '/')
828 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
829 if (!p->rpath) return -1;
833 while ((t=strchr(s, '$'))) {
836 memcpy(d, origin, l);
838 /* It was determined previously that the '$' is followed
839 * either by "ORIGIN" or "{ORIGIN}". */
840 s = t + 7 + 2*(t[1]=='{');
846 static void decode_dyn(struct dso *p)
849 decode_vec(p->dynv, dyn, DYN_CNT);
850 p->syms = laddr(p, dyn[DT_SYMTAB]);
851 p->strings = laddr(p, dyn[DT_STRTAB]);
852 if (dyn[0]&(1<<DT_HASH))
853 p->hashtab = laddr(p, dyn[DT_HASH]);
854 if (dyn[0]&(1<<DT_RPATH))
855 p->rpath_orig = p->strings + dyn[DT_RPATH];
856 if (dyn[0]&(1<<DT_RUNPATH))
857 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
858 if (dyn[0]&(1<<DT_PLTGOT))
859 p->got = laddr(p, dyn[DT_PLTGOT]);
860 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
861 p->ghashtab = laddr(p, *dyn);
862 if (search_vec(p->dynv, dyn, DT_VERSYM))
863 p->versym = laddr(p, *dyn);
866 static size_t count_syms(struct dso *p)
868 if (p->hashtab) return p->hashtab[1];
871 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
873 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
874 if (buckets[i] > nsym)
878 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
880 while (!(*hashval++ & 1));
885 static void *dl_mmap(size_t n)
888 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
890 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
892 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
894 return p == MAP_FAILED ? 0 : p;
897 static void makefuncdescs(struct dso *p)
899 static int self_done;
900 size_t nsym = count_syms(p);
901 size_t i, size = nsym * sizeof(*p->funcdescs);
904 p->funcdescs = dl_mmap(size);
907 p->funcdescs = malloc(size);
910 if (!runtime) a_crash();
911 error("Error allocating function descriptors for %s", p->name);
912 longjmp(*rtld_fail, 1);
914 for (i=0; i<nsym; i++) {
915 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
916 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
917 p->funcdescs[i].got = p->got;
919 p->funcdescs[i].addr = 0;
920 p->funcdescs[i].got = 0;
925 static struct dso *load_library(const char *name, struct dso *needed_by)
927 char buf[2*NAME_MAX+2];
928 const char *pathname;
930 struct dso *p, temp_dso = {0};
942 /* Catch and block attempts to reload the implementation itself */
943 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
944 static const char reserved[] =
945 "c.pthread.rt.m.dl.util.xnet.";
946 const char *rp, *next;
947 for (rp=reserved; *rp; rp=next) {
948 next = strchr(rp, '.') + 1;
949 if (strncmp(name+3, rp, next-rp) == 0)
954 /* Track which names have been resolved
955 * and only report each one once. */
956 static unsigned reported;
957 unsigned mask = 1U<<(rp-reserved);
958 if (!(reported & mask)) {
960 dprintf(1, "\t%s => %s (%p)\n",
968 if (!strcmp(name, ldso.name)) is_self = 1;
977 if (strchr(name, '/')) {
979 fd = open(name, O_RDONLY|O_CLOEXEC);
981 /* Search for the name to see if it's already loaded */
982 for (p=head->next; p; p=p->next) {
983 if (p->shortname && !strcmp(p->shortname, name)) {
987 if (strlen(name) > NAME_MAX) return 0;
989 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
990 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
991 if (fixup_rpath(p, buf, sizeof buf) < 0)
992 fd = -2; /* Inhibit further search. */
994 fd = path_open(name, p->rpath, buf, sizeof buf);
1000 if (ldso.name[0]=='/') {
1002 for (s=t=z=ldso.name; *s; s++)
1003 if (*s=='/') z=t, t=s;
1004 prefix_len = z-ldso.name;
1005 if (prefix_len < PATH_MAX)
1012 char etc_ldso_path[prefix_len + 1
1013 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1014 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1015 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1016 (int)prefix_len, prefix);
1017 FILE *f = fopen(etc_ldso_path, "rbe");
1019 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1024 } else if (errno != ENOENT) {
1028 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1029 fd = path_open(name, sys_path, buf, sizeof buf);
1033 if (fd < 0) return 0;
1034 if (fstat(fd, &st) < 0) {
1038 for (p=head->next; p; p=p->next) {
1039 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1040 /* If this library was previously loaded with a
1041 * pathname but a search found the same inode,
1042 * setup its shortname so it can be found by name. */
1043 if (!p->shortname && pathname != name)
1044 p->shortname = strrchr(p->name, '/')+1;
1049 map = noload ? 0 : map_library(fd, &temp_dso);
1053 /* Avoid the danger of getting two versions of libc mapped into the
1054 * same process when an absolute pathname was used. The symbols
1055 * checked are chosen to catch both musl and glibc, and to avoid
1056 * false positives from interposition-hack libraries. */
1057 decode_dyn(&temp_dso);
1058 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1059 find_sym(&temp_dso, "stdin", 1).sym) {
1060 unmap_library(&temp_dso);
1061 return load_library("libc.so", needed_by);
1063 /* Past this point, if we haven't reached runtime yet, ldso has
1064 * committed either to use the mapped library or to abort execution.
1065 * Unmapping is not possible, so we can safely reclaim gaps. */
1066 if (!runtime) reclaim_gaps(&temp_dso);
1068 /* Allocate storage for the new DSO. When there is TLS, this
1069 * storage must include a reservation for all pre-existing
1070 * threads to obtain copies of both the new TLS, and an
1071 * extended DTV capable of storing an additional slot for
1072 * the newly-loaded DSO. */
1073 alloc_size = sizeof *p + strlen(pathname) + 1;
1074 if (runtime && temp_dso.tls.image) {
1075 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1076 + sizeof(void *) * (tls_cnt+3);
1077 n_th = libc.threads_minus_1 + 1;
1078 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1079 else alloc_size += n_th * per_th;
1081 p = calloc(1, alloc_size);
1083 unmap_library(&temp_dso);
1086 memcpy(p, &temp_dso, sizeof temp_dso);
1089 p->needed_by = needed_by;
1091 strcpy(p->name, pathname);
1092 /* Add a shortname only if name arg was not an explicit pathname. */
1093 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1095 p->tls_id = ++tls_cnt;
1096 tls_align = MAXP2(tls_align, p->tls.align);
1098 p->tls.offset = tls_offset + ( (tls_align-1) &
1099 -(tls_offset + (uintptr_t)p->tls.image) );
1100 tls_offset += p->tls.size;
1102 tls_offset += p->tls.size + p->tls.align - 1;
1103 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1105 p->tls.offset = tls_offset;
1107 p->new_dtv = (void *)(-sizeof(size_t) &
1108 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1109 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1110 if (tls_tail) tls_tail->next = &p->tls;
1111 else libc.tls_head = &p->tls;
1119 if (DL_FDPIC) makefuncdescs(p);
1121 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1126 static void load_deps(struct dso *p)
1129 struct dso ***deps = &p->deps, **tmp, *dep;
1130 for (; p; p=p->next) {
1131 for (i=0; p->dynv[i]; i+=2) {
1132 if (p->dynv[i] != DT_NEEDED) continue;
1133 dep = load_library(p->strings + p->dynv[i+1], p);
1135 error("Error loading shared library %s: %m (needed by %s)",
1136 p->strings + p->dynv[i+1], p->name);
1137 if (runtime) longjmp(*rtld_fail, 1);
1141 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1142 if (!tmp) longjmp(*rtld_fail, 1);
1149 if (!*deps) *deps = (struct dso **)&nodeps_dummy;
1152 static void load_preload(char *s)
1156 for (z=s; *z; s=z) {
1157 for ( ; *s && (isspace(*s) || *s==':'); s++);
1158 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1166 static void add_syms(struct dso *p)
1168 if (!p->syms_next && syms_tail != p) {
1169 syms_tail->syms_next = p;
1174 static void revert_syms(struct dso *old_tail)
1176 struct dso *p, *next;
1177 /* Chop off the tail of the list of dsos that participate in
1178 * the global symbol table, reverting them to RTLD_LOCAL. */
1179 for (p=old_tail; p; p=next) {
1180 next = p->syms_next;
1183 syms_tail = old_tail;
1186 static void do_mips_relocs(struct dso *p, size_t *got)
1188 size_t i, j, rel[2];
1189 unsigned char *base = p->base;
1190 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1194 while (i--) *got++ += (size_t)base;
1196 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1197 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1198 Sym *sym = p->syms + j;
1199 rel[0] = (unsigned char *)got - base;
1200 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1201 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1202 do_relocs(p, rel, sizeof rel, 2);
1206 static void reloc_all(struct dso *p)
1208 size_t dyn[DYN_CNT];
1209 for (; p; p=p->next) {
1210 if (p->relocated) continue;
1211 decode_vec(p->dynv, dyn, DYN_CNT);
1212 if (NEED_MIPS_GOT_RELOCS)
1213 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1214 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1215 2+(dyn[DT_PLTREL]==DT_RELA));
1216 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1217 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1219 if (head != &ldso && p->relro_start != p->relro_end &&
1220 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1221 && errno != ENOSYS) {
1222 error("Error relocating %s: RELRO protection failed: %m",
1224 if (runtime) longjmp(*rtld_fail, 1);
1231 static void kernel_mapped_dso(struct dso *p)
1233 size_t min_addr = -1, max_addr = 0, cnt;
1235 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1236 if (ph->p_type == PT_DYNAMIC) {
1237 p->dynv = laddr(p, ph->p_vaddr);
1238 } else if (ph->p_type == PT_GNU_RELRO) {
1239 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1240 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1242 if (ph->p_type != PT_LOAD) continue;
1243 if (ph->p_vaddr < min_addr)
1244 min_addr = ph->p_vaddr;
1245 if (ph->p_vaddr+ph->p_memsz > max_addr)
1246 max_addr = ph->p_vaddr+ph->p_memsz;
1248 min_addr &= -PAGE_SIZE;
1249 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1250 p->map = p->base + min_addr;
1251 p->map_len = max_addr - min_addr;
1252 p->kernel_mapped = 1;
1255 void __libc_exit_fini()
1258 size_t dyn[DYN_CNT];
1259 for (p=fini_head; p; p=p->fini_next) {
1260 if (!p->constructed) continue;
1261 decode_vec(p->dynv, dyn, DYN_CNT);
1262 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1263 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1264 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1265 while (n--) ((void (*)(void))*--fn)();
1267 #ifndef NO_LEGACY_INITFINI
1268 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1269 fpaddr(p, dyn[DT_FINI])();
1274 static void do_init_fini(struct dso *p)
1276 size_t dyn[DYN_CNT];
1277 int need_locking = libc.threads_minus_1;
1278 /* Allow recursive calls that arise when a library calls
1279 * dlopen from one of its constructors, but block any
1280 * other threads until all ctors have finished. */
1281 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1282 for (; p; p=p->prev) {
1283 if (p->constructed) continue;
1285 decode_vec(p->dynv, dyn, DYN_CNT);
1286 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1287 p->fini_next = fini_head;
1290 #ifndef NO_LEGACY_INITFINI
1291 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1292 fpaddr(p, dyn[DT_INIT])();
1294 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1295 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1296 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1297 while (n--) ((void (*)(void))*fn++)();
1299 if (!need_locking && libc.threads_minus_1) {
1301 pthread_mutex_lock(&init_fini_lock);
1304 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1307 void __libc_start_init(void)
1312 static void dl_debug_state(void)
1316 weak_alias(dl_debug_state, _dl_debug_state);
1318 void __init_tls(size_t *auxv)
1322 hidden void *__tls_get_new(tls_mod_off_t *v)
1324 pthread_t self = __pthread_self();
1326 /* Block signals to make accessing new TLS async-signal-safe */
1328 __block_all_sigs(&set);
1329 if (v[0]<=(size_t)self->dtv[0]) {
1330 __restore_sigs(&set);
1331 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1334 /* This is safe without any locks held because, if the caller
1335 * is able to request the Nth entry of the DTV, the DSO list
1336 * must be valid at least that far out and it was synchronized
1337 * at program startup or by an already-completed call to dlopen. */
1339 for (p=head; p->tls_id != v[0]; p=p->next);
1341 /* Get new DTV space from new DSO if needed */
1342 if (v[0] > (size_t)self->dtv[0]) {
1343 void **newdtv = p->new_dtv +
1344 (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
1345 memcpy(newdtv, self->dtv,
1346 ((size_t)self->dtv[0]+1) * sizeof(void *));
1347 newdtv[0] = (void *)v[0];
1348 self->dtv = self->dtv_copy = newdtv;
1351 /* Get new TLS memory from all new DSOs up to the requested one */
1353 for (p=head; ; p=p->next) {
1354 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1355 mem = p->new_tls + (p->tls.size + p->tls.align)
1356 * a_fetch_add(&p->new_tls_idx,1);
1357 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1359 self->dtv[p->tls_id] = mem;
1360 memcpy(mem, p->tls.image, p->tls.len);
1361 if (p->tls_id == v[0]) break;
1363 __restore_sigs(&set);
1364 return mem + v[1] + DTP_OFFSET;
1367 static void update_tls_size()
1369 libc.tls_cnt = tls_cnt;
1370 libc.tls_align = tls_align;
1371 libc.tls_size = ALIGN(
1372 (1+tls_cnt) * sizeof(void *) +
1374 sizeof(struct pthread) +
1379 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1380 * following stage 2 and stage 3 functions via primitive symbolic lookup
1381 * since it does not have access to their addresses to begin with. */
1383 /* Stage 2 of the dynamic linker is called after relative relocations
1384 * have been processed. It can make function calls to static functions
1385 * and access string literals and static data, but cannot use extern
1386 * symbols. Its job is to perform symbolic relocations on the dynamic
1387 * linker itself, but some of the relocations performed may need to be
1388 * replaced later due to copy relocations in the main program. */
1390 hidden void __dls2(unsigned char *base, size_t *sp)
1393 void *p1 = (void *)sp[-2];
1394 void *p2 = (void *)sp[-1];
1396 size_t *auxv, aux[AUX_CNT];
1397 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1398 decode_vec(auxv, aux, AUX_CNT);
1399 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1400 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1402 app_loadmap = p2 ? p1 : 0;
1403 ldso.loadmap = p2 ? p2 : p1;
1404 ldso.base = laddr(&ldso, 0);
1408 Ehdr *ehdr = (void *)ldso.base;
1409 ldso.name = ldso.shortname = "libc.so";
1410 ldso.phnum = ehdr->e_phnum;
1411 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1412 ldso.phentsize = ehdr->e_phentsize;
1413 kernel_mapped_dso(&ldso);
1416 if (DL_FDPIC) makefuncdescs(&ldso);
1418 /* Prepare storage for to save clobbered REL addends so they
1419 * can be reused in stage 3. There should be very few. If
1420 * something goes wrong and there are a huge number, abort
1421 * instead of risking stack overflow. */
1422 size_t dyn[DYN_CNT];
1423 decode_vec(ldso.dynv, dyn, DYN_CNT);
1424 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1425 size_t rel_size = dyn[DT_RELSZ];
1426 size_t symbolic_rel_cnt = 0;
1427 apply_addends_to = rel;
1428 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1429 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1430 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1431 size_t addends[symbolic_rel_cnt+1];
1432 saved_addends = addends;
1439 /* Call dynamic linker stage-3, __dls3, looking it up
1440 * symbolically as a barrier against moving the address
1441 * load across the above relocation processing. */
1442 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1443 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1444 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1447 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1448 * fully functional. Its job is to load (if not already loaded) and
1449 * process dependencies and relocations for the main application and
1450 * transfer control to its entry point. */
1452 _Noreturn void __dls3(size_t *sp)
1454 static struct dso app, vdso;
1455 size_t aux[AUX_CNT], *auxv;
1457 char *env_preload=0;
1458 char *replace_argv0=0;
1461 char **argv = (void *)(sp+1);
1462 char **argv_orig = argv;
1463 char **envp = argv+argc+1;
1465 /* Find aux vector just past environ[] and use it to initialize
1466 * global data that may be needed before we can make syscalls. */
1468 for (i=argc+1; argv[i]; i++);
1469 libc.auxv = auxv = (void *)(argv+i+1);
1470 decode_vec(auxv, aux, AUX_CNT);
1471 __hwcap = aux[AT_HWCAP];
1472 libc.page_size = aux[AT_PAGESZ];
1473 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1474 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1476 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1477 * use during dynamic linking. If possible it will also serve as the
1478 * thread pointer at runtime. */
1479 libc.tls_size = sizeof builtin_tls;
1480 libc.tls_align = tls_align;
1481 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1485 /* Only trust user/env if kernel says we're not suid/sgid */
1487 env_path = getenv("LD_LIBRARY_PATH");
1488 env_preload = getenv("LD_PRELOAD");
1491 /* If the main program was already loaded by the kernel,
1492 * AT_PHDR will point to some location other than the dynamic
1493 * linker's program headers. */
1494 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1495 size_t interp_off = 0;
1496 size_t tls_image = 0;
1497 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1498 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1499 app.phnum = aux[AT_PHNUM];
1500 app.phentsize = aux[AT_PHENT];
1501 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1502 if (phdr->p_type == PT_PHDR)
1503 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1504 else if (phdr->p_type == PT_INTERP)
1505 interp_off = (size_t)phdr->p_vaddr;
1506 else if (phdr->p_type == PT_TLS) {
1507 tls_image = phdr->p_vaddr;
1508 app.tls.len = phdr->p_filesz;
1509 app.tls.size = phdr->p_memsz;
1510 app.tls.align = phdr->p_align;
1513 if (DL_FDPIC) app.loadmap = app_loadmap;
1514 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1515 if (interp_off) ldso.name = laddr(&app, interp_off);
1516 if ((aux[0] & (1UL<<AT_EXECFN))
1517 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1518 app.name = (char *)aux[AT_EXECFN];
1521 kernel_mapped_dso(&app);
1524 char *ldname = argv[0];
1525 size_t l = strlen(ldname);
1526 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1528 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1529 char *opt = argv[0]+2;
1530 *argv++ = (void *)-1;
1533 } else if (!memcmp(opt, "list", 5)) {
1535 } else if (!memcmp(opt, "library-path", 12)) {
1536 if (opt[12]=='=') env_path = opt+13;
1537 else if (opt[12]) *argv = 0;
1538 else if (*argv) env_path = *argv++;
1539 } else if (!memcmp(opt, "preload", 7)) {
1540 if (opt[7]=='=') env_preload = opt+8;
1541 else if (opt[7]) *argv = 0;
1542 else if (*argv) env_preload = *argv++;
1543 } else if (!memcmp(opt, "argv0", 5)) {
1544 if (opt[5]=='=') replace_argv0 = opt+6;
1545 else if (opt[5]) *argv = 0;
1546 else if (*argv) replace_argv0 = *argv++;
1551 argv[-1] = (void *)(argc - (argv-argv_orig));
1553 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1555 "Dynamic Program Loader\n"
1556 "Usage: %s [options] [--] pathname%s\n",
1557 __libc_version, ldname,
1558 ldd_mode ? "" : " [args]");
1561 fd = open(argv[0], O_RDONLY);
1563 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1566 Ehdr *ehdr = (void *)map_library(fd, &app);
1568 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1574 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1575 /* Find the name that would have been used for the dynamic
1576 * linker had ldd not taken its place. */
1578 for (i=0; i<app.phnum; i++) {
1579 if (app.phdr[i].p_type == PT_INTERP)
1580 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1582 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1586 libc.tls_head = tls_tail = &app.tls;
1587 app.tls_id = tls_cnt = 1;
1589 app.tls.offset = GAP_ABOVE_TP;
1590 app.tls.offset += -GAP_ABOVE_TP & (app.tls.align-1);
1591 tls_offset = app.tls.offset + app.tls.size
1592 + ( -((uintptr_t)app.tls.image + app.tls.size)
1593 & (app.tls.align-1) );
1595 tls_offset = app.tls.offset = app.tls.size
1596 + ( -((uintptr_t)app.tls.image + app.tls.size)
1597 & (app.tls.align-1) );
1599 tls_align = MAXP2(tls_align, app.tls.align);
1603 makefuncdescs(&app);
1605 app.loadmap = (void *)&app_dummy_loadmap;
1606 app.loadmap->nsegs = 1;
1607 app.loadmap->segs[0].addr = (size_t)app.map;
1608 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1610 app.loadmap->segs[0].p_memsz = app.map_len;
1612 argv[-3] = (void *)app.loadmap;
1615 /* Initial dso chain consists only of the app. */
1616 head = tail = syms_tail = &app;
1618 /* Donate unused parts of app and library mapping to malloc */
1620 reclaim_gaps(&ldso);
1622 /* Load preload/needed libraries, add symbols to global namespace. */
1623 if (env_preload) load_preload(env_preload);
1625 for (struct dso *p=head; p; p=p->next)
1628 /* Attach to vdso, if provided by the kernel, last so that it does
1629 * not become part of the global namespace. */
1630 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1631 Ehdr *ehdr = (void *)vdso_base;
1632 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1633 vdso.phnum = ehdr->e_phnum;
1634 vdso.phentsize = ehdr->e_phentsize;
1635 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1636 if (phdr->p_type == PT_DYNAMIC)
1637 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1638 if (phdr->p_type == PT_LOAD)
1639 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1642 vdso.shortname = "linux-gate.so.1";
1650 for (i=0; app.dynv[i]; i+=2) {
1651 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1652 app.dynv[i+1] = (size_t)&debug;
1653 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1654 size_t *ptr = (size_t *) app.dynv[i+1];
1655 *ptr = (size_t)&debug;
1659 /* The main program must be relocated LAST since it may contin
1660 * copy relocations which depend on libraries' relocations. */
1661 reloc_all(app.next);
1665 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1666 void *initial_tls = calloc(libc.tls_size, 1);
1668 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1669 argv[0], libc.tls_size);
1672 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1676 size_t tmp_tls_size = libc.tls_size;
1677 pthread_t self = __pthread_self();
1678 /* Temporarily set the tls size to the full size of
1679 * builtin_tls so that __copy_tls will use the same layout
1680 * as it did for before. Then check, just to be safe. */
1681 libc.tls_size = sizeof builtin_tls;
1682 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1683 libc.tls_size = tmp_tls_size;
1685 static_tls_cnt = tls_cnt;
1687 if (ldso_fail) _exit(127);
1688 if (ldd_mode) _exit(0);
1690 /* Determine if malloc was interposed by a replacement implementation
1691 * so that calloc and the memalign family can harden against the
1692 * possibility of incomplete replacement. */
1693 if (find_sym(head, "malloc", 1).dso != &ldso)
1694 __malloc_replaced = 1;
1696 /* Switch to runtime mode: any further failures in the dynamic
1697 * linker are a reportable failure rather than a fatal startup
1702 debug.bp = dl_debug_state;
1704 debug.base = ldso.base;
1708 if (replace_argv0) argv[0] = replace_argv0;
1712 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1716 static void prepare_lazy(struct dso *p)
1718 size_t dyn[DYN_CNT], n, flags1=0;
1719 decode_vec(p->dynv, dyn, DYN_CNT);
1720 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1721 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1723 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1724 if (NEED_MIPS_GOT_RELOCS) {
1725 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1726 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1729 p->lazy = calloc(n, 3*sizeof(size_t));
1731 error("Error preparing lazy relocation for %s: %m", p->name);
1732 longjmp(*rtld_fail, 1);
1734 p->lazy_next = lazy_head;
1738 void *dlopen(const char *file, int mode)
1740 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1741 struct tls_module *orig_tls_tail;
1742 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1747 if (!file) return head;
1749 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1750 pthread_rwlock_wrlock(&lock);
1754 orig_tls_tail = tls_tail;
1755 orig_tls_cnt = tls_cnt;
1756 orig_tls_offset = tls_offset;
1757 orig_tls_align = tls_align;
1758 orig_lazy_head = lazy_head;
1759 orig_syms_tail = syms_tail;
1761 noload = mode & RTLD_NOLOAD;
1764 if (setjmp(*rtld_fail)) {
1765 /* Clean up anything new that was (partially) loaded */
1766 revert_syms(orig_syms_tail);
1767 for (p=orig_tail->next; p; p=next) {
1769 while (p->td_index) {
1770 void *tmp = p->td_index->next;
1775 if (p->rpath != p->rpath_orig)
1777 if (p->deps != &nodeps_dummy)
1782 if (!orig_tls_tail) libc.tls_head = 0;
1783 tls_tail = orig_tls_tail;
1784 if (tls_tail) tls_tail->next = 0;
1785 tls_cnt = orig_tls_cnt;
1786 tls_offset = orig_tls_offset;
1787 tls_align = orig_tls_align;
1788 lazy_head = orig_lazy_head;
1793 } else p = load_library(file, head);
1797 "Library %s is not already loaded" :
1798 "Error loading shared library %s: %m",
1803 /* First load handling */
1804 int first_load = !p->deps;
1807 if (!p->relocated && (mode & RTLD_LAZY)) {
1809 for (i=0; p->deps[i]; i++)
1810 if (!p->deps[i]->relocated)
1811 prepare_lazy(p->deps[i]);
1814 if (first_load || (mode & RTLD_GLOBAL)) {
1815 /* Make new symbols global, at least temporarily, so we can do
1816 * relocations. If not RTLD_GLOBAL, this is reverted below. */
1818 for (i=0; p->deps[i]; i++)
1819 add_syms(p->deps[i]);
1825 /* If RTLD_GLOBAL was not specified, undo any new additions
1826 * to the global symbol table. This is a nop if the library was
1827 * previously loaded and already global. */
1828 if (!(mode & RTLD_GLOBAL))
1829 revert_syms(orig_syms_tail);
1831 /* Processing of deferred lazy relocations must not happen until
1832 * the new libraries are committed; otherwise we could end up with
1833 * relocations resolved to symbol definitions that get removed. */
1842 pthread_rwlock_unlock(&lock);
1843 if (p) do_init_fini(orig_tail);
1844 pthread_setcancelstate(cs, 0);
1848 hidden int __dl_invalid_handle(void *h)
1851 for (p=head; p; p=p->next) if (h==p) return 0;
1852 error("Invalid library handle %p", (void *)h);
1856 static void *addr2dso(size_t a)
1860 if (DL_FDPIC) for (p=head; p; p=p->next) {
1862 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1865 for (p=head; p; p=p->next) {
1866 if (DL_FDPIC && p->loadmap) {
1867 for (i=0; i<p->loadmap->nsegs; i++) {
1868 if (a-p->loadmap->segs[i].p_vaddr
1869 < p->loadmap->segs[i].p_memsz)
1874 size_t phcnt = p->phnum;
1875 size_t entsz = p->phentsize;
1876 size_t base = (size_t)p->base;
1877 for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
1878 if (ph->p_type != PT_LOAD) continue;
1879 if (a-base-ph->p_vaddr < ph->p_memsz)
1882 if (a-(size_t)p->map < p->map_len)
1889 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1892 uint32_t h = 0, gh = 0, *ght;
1894 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1895 if (p == RTLD_DEFAULT) {
1897 } else if (p == RTLD_NEXT) {
1898 p = addr2dso((size_t)ra);
1902 struct symdef def = find_sym(p, s, 0);
1903 if (!def.sym) goto failed;
1904 if ((def.sym->st_info&0xf) == STT_TLS)
1905 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value});
1906 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1907 return def.dso->funcdescs + (def.sym - def.dso->syms);
1908 return laddr(def.dso, def.sym->st_value);
1910 if (__dl_invalid_handle(p))
1912 if ((ght = p->ghashtab)) {
1914 sym = gnu_lookup(gh, ght, p, s);
1917 sym = sysv_lookup(s, h, p);
1919 if (sym && (sym->st_info&0xf) == STT_TLS)
1920 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value});
1921 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1922 return p->funcdescs + (sym - p->syms);
1923 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1924 return laddr(p, sym->st_value);
1925 for (i=0; p->deps[i]; i++) {
1926 if ((ght = p->deps[i]->ghashtab)) {
1927 if (!gh) gh = gnu_hash(s);
1928 sym = gnu_lookup(gh, ght, p->deps[i], s);
1930 if (!h) h = sysv_hash(s);
1931 sym = sysv_lookup(s, h, p->deps[i]);
1933 if (sym && (sym->st_info&0xf) == STT_TLS)
1934 return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value});
1935 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1936 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1937 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1938 return laddr(p->deps[i], sym->st_value);
1941 error("Symbol not found: %s", s);
1945 int dladdr(const void *addr_arg, Dl_info *info)
1947 size_t addr = (size_t)addr_arg;
1953 size_t besterr = -1;
1955 pthread_rwlock_rdlock(&lock);
1957 pthread_rwlock_unlock(&lock);
1962 strings = p->strings;
1963 nsym = count_syms(p);
1966 size_t idx = (addr-(size_t)p->funcdescs)
1967 / sizeof(*p->funcdescs);
1968 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1969 best = (size_t)(p->funcdescs + idx);
1970 bestsym = sym + idx;
1975 if (!best) for (; nsym; nsym--, sym++) {
1977 && (1<<(sym->st_info&0xf) & OK_TYPES)
1978 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1979 size_t symaddr = (size_t)laddr(p, sym->st_value);
1980 if (symaddr > addr || symaddr <= best)
1984 besterr = addr - symaddr;
1985 if (addr == symaddr)
1990 if (bestsym && besterr > bestsym->st_size-1) {
1995 info->dli_fname = p->name;
1996 info->dli_fbase = p->map;
1999 info->dli_sname = 0;
2000 info->dli_saddr = 0;
2004 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2005 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2006 info->dli_sname = strings + bestsym->st_name;
2007 info->dli_saddr = (void *)best;
2012 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2015 pthread_rwlock_rdlock(&lock);
2016 res = do_dlsym(p, s, ra);
2017 pthread_rwlock_unlock(&lock);
2021 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2023 struct dso *current;
2024 struct dl_phdr_info info;
2026 for(current = head; current;) {
2027 info.dlpi_addr = (uintptr_t)current->base;
2028 info.dlpi_name = current->name;
2029 info.dlpi_phdr = current->phdr;
2030 info.dlpi_phnum = current->phnum;
2031 info.dlpi_adds = gencnt;
2033 info.dlpi_tls_modid = current->tls_id;
2034 info.dlpi_tls_data = current->tls.image;
2036 ret = (callback)(&info, sizeof (info), data);
2038 if (ret != 0) break;
2040 pthread_rwlock_rdlock(&lock);
2041 current = current->next;
2042 pthread_rwlock_unlock(&lock);
2047 static void error(const char *fmt, ...)
2052 vdprintf(2, fmt, ap);
2058 __dl_vseterr(fmt, ap);