20 #include "pthread_impl.h"
24 static void error(const char *, ...);
26 #define MAXP2(a,b) (-(-(a)&-(b)))
27 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
39 struct td_index *next;
44 struct fdpic_loadmap *loadmap;
50 struct dso *next, *prev;
60 struct dso *syms_next, *lazy_next;
61 size_t *lazy, lazy_cnt;
69 struct dso **deps, *needed_by;
70 char *rpath_orig, *rpath;
71 struct tls_module tls;
73 size_t relro_start, relro_end;
75 unsigned char *new_tls;
76 volatile int new_dtv_idx, new_tls_idx;
77 struct td_index *td_index;
78 struct dso *fini_next;
83 struct fdpic_loadmap *loadmap;
98 int __init_tp(void *);
99 void __init_libc(char **, char *);
100 void *__copy_tls(unsigned char *);
102 __attribute__((__visibility__("hidden")))
103 const char *__libc_get_version(void);
105 static struct builtin_tls {
110 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
112 #define ADDEND_LIMIT 4096
113 static size_t *saved_addends, *apply_addends_to;
115 static struct dso ldso;
116 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
117 static char *env_path, *sys_path;
118 static unsigned long long gencnt;
121 static int ldso_fail;
123 static jmp_buf *rtld_fail;
124 static pthread_rwlock_t lock;
125 static struct debug debug;
126 static struct tls_module *tls_tail;
127 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
128 static size_t static_tls_cnt;
129 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
130 static struct fdpic_loadmap *app_loadmap;
131 static struct fdpic_dummy_loadmap app_dummy_loadmap;
132 static struct dso *const nodeps_dummy;
134 struct debug *_dl_debug_addr = &debug;
136 __attribute__((__visibility__("hidden")))
137 void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
139 __attribute__((__visibility__("hidden")))
140 extern void (*const __init_array_end)(void), (*const __fini_array_end)(void);
142 weak_alias(__init_array_start, __init_array_end);
143 weak_alias(__fini_array_start, __fini_array_end);
145 static int dl_strcmp(const char *l, const char *r)
147 for (; *l==*r && *l; l++, r++);
148 return *(unsigned char *)l - *(unsigned char *)r;
150 #define strcmp(l,r) dl_strcmp(l,r)
152 /* Compute load address for a virtual address in a given dso. */
154 static void *laddr(const struct dso *p, size_t v)
157 if (!p->loadmap) return p->base + v;
158 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
159 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
161 static void *laddr_pg(const struct dso *p, size_t v)
164 size_t pgsz = PAGE_SIZE;
165 if (!p->loadmap) return p->base + v;
167 size_t a = p->loadmap->segs[j].p_vaddr;
168 size_t b = a + p->loadmap->segs[j].p_memsz;
174 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
176 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
177 laddr(p, v), (p)->got })
179 #define laddr(p, v) (void *)((p)->base + (v))
180 #define laddr_pg(p, v) laddr(p, v)
181 #define fpaddr(p, v) ((void (*)())laddr(p, v))
184 static void decode_vec(size_t *v, size_t *a, size_t cnt)
187 for (i=0; i<cnt; i++) a[i] = 0;
188 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
194 static int search_vec(size_t *v, size_t *r, size_t key)
196 for (; v[0]!=key; v+=2)
202 static uint32_t sysv_hash(const char *s0)
204 const unsigned char *s = (void *)s0;
210 return h & 0xfffffff;
213 static uint32_t gnu_hash(const char *s0)
215 const unsigned char *s = (void *)s0;
216 uint_fast32_t h = 5381;
222 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
225 Sym *syms = dso->syms;
226 Elf_Symndx *hashtab = dso->hashtab;
227 char *strings = dso->strings;
228 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
229 if ((!dso->versym || dso->versym[i] >= 0)
230 && (!strcmp(s, strings+syms[i].st_name)))
236 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
238 uint32_t nbuckets = hashtab[0];
239 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
240 uint32_t i = buckets[h1 % nbuckets];
244 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
246 for (h1 |= 1; ; i++) {
247 uint32_t h2 = *hashval++;
248 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
249 && !strcmp(s, dso->strings + dso->syms[i].st_name))
257 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
259 const size_t *bloomwords = (const void *)(hashtab+4);
260 size_t f = bloomwords[fofs & (hashtab[2]-1)];
261 if (!(f & fmask)) return 0;
263 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
264 if (!(f & 1)) return 0;
266 return gnu_lookup(h1, hashtab, dso, s);
269 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
270 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
272 #ifndef ARCH_SYM_REJECT_UND
273 #define ARCH_SYM_REJECT_UND(s) 0
276 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
278 uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
279 size_t ghm = 1ul << gh % (8*sizeof(size_t));
280 struct symdef def = {0};
281 for (; dso; dso=dso->syms_next) {
283 if ((ght = dso->ghashtab)) {
284 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
286 if (!h) h = sysv_hash(s);
287 sym = sysv_lookup(s, h, dso);
291 if (need_def || (sym->st_info&0xf) == STT_TLS
292 || ARCH_SYM_REJECT_UND(sym))
295 if ((sym->st_info&0xf) != STT_TLS)
297 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
298 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
306 __attribute__((__visibility__("hidden")))
307 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
309 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
311 unsigned char *base = dso->base;
312 Sym *syms = dso->syms;
313 char *strings = dso->strings;
324 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
327 /* Only ldso's REL table needs addend saving/reuse. */
328 if (rel == apply_addends_to)
333 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
334 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
335 type = R_TYPE(rel[1]);
336 if (type == REL_NONE) continue;
337 reloc_addr = laddr(dso, rel[0]);
341 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
343 } else if (reuse_addends) {
344 /* Save original addend in stage 2 where the dso
345 * chain consists of just ldso; otherwise read back
346 * saved addend since the inline one was clobbered. */
348 saved_addends[save_slot] = *reloc_addr;
349 addend = saved_addends[save_slot++];
351 addend = *reloc_addr;
354 sym_index = R_SYM(rel[1]);
356 sym = syms + sym_index;
357 name = strings + sym->st_name;
358 ctx = type==REL_COPY ? head->syms_next : head;
359 def = (sym->st_info&0xf) == STT_SECTION
360 ? (struct symdef){ .dso = dso, .sym = sym }
361 : find_sym(ctx, name, type==REL_PLT);
362 if (!def.sym && (sym->st_shndx != SHN_UNDEF
363 || sym->st_info>>4 != STB_WEAK)) {
364 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
365 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
366 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
367 dso->lazy[3*dso->lazy_cnt+2] = addend;
371 error("Error relocating %s: %s: symbol not found",
373 if (runtime) longjmp(*rtld_fail, 1);
382 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
383 tls_val = def.sym ? def.sym->st_value : 0;
389 addend -= (size_t)reloc_addr;
393 *reloc_addr = sym_val + addend;
396 *reloc_addr = (size_t)base + addend;
399 if (sym) *reloc_addr = sym_val + addend;
400 else *reloc_addr = (size_t)base + addend;
403 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
406 *(uint32_t *)reloc_addr = sym_val + addend
407 - (size_t)reloc_addr;
410 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
411 + (def.sym - def.dso->syms)) : 0;
413 case REL_FUNCDESC_VAL:
414 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
415 else *reloc_addr = sym_val;
416 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
419 *reloc_addr = def.dso->tls_id;
422 *reloc_addr = tls_val + addend - DTP_OFFSET;
426 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
430 *reloc_addr = tls_val - def.dso->tls.offset + addend;
433 *reloc_addr = def.dso->tls.offset - tls_val + addend;
437 if (stride<3) addend = reloc_addr[1];
438 if (runtime && def.dso->tls_id >= static_tls_cnt) {
439 struct td_index *new = malloc(sizeof *new);
442 "Error relocating %s: cannot allocate TLSDESC for %s",
443 dso->name, sym ? name : "(local)" );
444 longjmp(*rtld_fail, 1);
446 new->next = dso->td_index;
448 new->args[0] = def.dso->tls_id;
449 new->args[1] = tls_val + addend;
450 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
451 reloc_addr[1] = (size_t)new;
453 reloc_addr[0] = (size_t)__tlsdesc_static;
455 reloc_addr[1] = tls_val + def.dso->tls.offset
458 reloc_addr[1] = tls_val - def.dso->tls.offset
464 error("Error relocating %s: unsupported relocation type %d",
466 if (runtime) longjmp(*rtld_fail, 1);
472 static void redo_lazy_relocs()
474 struct dso *p = lazy_head, *next;
478 size_t size = p->lazy_cnt*3*sizeof(size_t);
480 do_relocs(p, p->lazy, size, 3);
482 p->lazy_next = lazy_head;
492 /* A huge hack: to make up for the wastefulness of shared libraries
493 * needing at least a page of dirty memory even if they have no global
494 * data, we reclaim the gaps at the beginning and end of writable maps
495 * and "donate" them to the heap. */
497 static void reclaim(struct dso *dso, size_t start, size_t end)
499 void __malloc_donate(char *, char *);
500 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
501 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
502 if (start >= end) return;
503 char *base = laddr_pg(dso, start);
504 __malloc_donate(base, base+(end-start));
507 static void reclaim_gaps(struct dso *dso)
509 Phdr *ph = dso->phdr;
510 size_t phcnt = dso->phnum;
512 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
513 if (ph->p_type!=PT_LOAD) continue;
514 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
515 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
516 reclaim(dso, ph->p_vaddr+ph->p_memsz,
517 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
521 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
523 static int no_map_fixed;
526 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
527 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
531 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
532 if (flags & MAP_ANONYMOUS) {
537 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
538 for (q=p; n; q+=r, off+=r, n-=r) {
540 if (r < 0 && errno != EINTR) return MAP_FAILED;
549 static void unmap_library(struct dso *dso)
553 for (i=0; i<dso->loadmap->nsegs; i++) {
554 if (!dso->loadmap->segs[i].p_memsz)
556 munmap((void *)dso->loadmap->segs[i].addr,
557 dso->loadmap->segs[i].p_memsz);
560 } else if (dso->map && dso->map_len) {
561 munmap(dso->map, dso->map_len);
565 static void *map_library(int fd, struct dso *dso)
567 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
568 void *allocated_buf=0;
570 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
571 size_t this_min, this_max;
577 unsigned char *map=MAP_FAILED, *base;
582 ssize_t l = read(fd, buf, sizeof buf);
585 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
587 phsize = eh->e_phentsize * eh->e_phnum;
588 if (phsize > sizeof buf - sizeof *eh) {
589 allocated_buf = malloc(phsize);
590 if (!allocated_buf) return 0;
591 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
592 if (l < 0) goto error;
593 if (l != phsize) goto noexec;
594 ph = ph0 = allocated_buf;
595 } else if (eh->e_phoff + phsize > l) {
596 l = pread(fd, buf+1, phsize, eh->e_phoff);
597 if (l < 0) goto error;
598 if (l != phsize) goto noexec;
599 ph = ph0 = (void *)(buf + 1);
601 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
603 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
604 if (ph->p_type == PT_DYNAMIC) {
606 } else if (ph->p_type == PT_TLS) {
607 tls_image = ph->p_vaddr;
608 dso->tls.align = ph->p_align;
609 dso->tls.len = ph->p_filesz;
610 dso->tls.size = ph->p_memsz;
611 } else if (ph->p_type == PT_GNU_RELRO) {
612 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
613 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
615 if (ph->p_type != PT_LOAD) continue;
617 if (ph->p_vaddr < addr_min) {
618 addr_min = ph->p_vaddr;
619 off_start = ph->p_offset;
620 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
621 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
622 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
624 if (ph->p_vaddr+ph->p_memsz > addr_max) {
625 addr_max = ph->p_vaddr+ph->p_memsz;
628 if (!dyn) goto noexec;
629 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
630 dso->loadmap = calloc(1, sizeof *dso->loadmap
631 + nsegs * sizeof *dso->loadmap->segs);
632 if (!dso->loadmap) goto error;
633 dso->loadmap->nsegs = nsegs;
634 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
635 if (ph->p_type != PT_LOAD) continue;
636 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
637 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
638 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
639 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
641 fd, ph->p_offset & -PAGE_SIZE);
642 if (map == MAP_FAILED) {
646 dso->loadmap->segs[i].addr = (size_t)map +
647 (ph->p_vaddr & PAGE_SIZE-1);
648 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
649 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
651 if (prot & PROT_WRITE) {
652 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
654 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
655 size_t pgend = brk + ph->p_memsz - ph->p_filesz
656 + PAGE_SIZE-1 & -PAGE_SIZE;
657 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
659 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
660 -1, off_start) == MAP_FAILED)
662 memset(map + brk, 0, pgbrk-brk);
665 map = (void *)dso->loadmap->segs[0].addr;
669 addr_max += PAGE_SIZE-1;
670 addr_max &= -PAGE_SIZE;
671 addr_min &= -PAGE_SIZE;
672 off_start &= -PAGE_SIZE;
673 map_len = addr_max - addr_min + off_start;
674 /* The first time, we map too much, possibly even more than
675 * the length of the file. This is okay because we will not
676 * use the invalid part; we just need to reserve the right
677 * amount of virtual address space to map over later. */
678 map = DL_NOMMU_SUPPORT
679 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
680 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
681 : mmap((void *)addr_min, map_len, prot,
682 MAP_PRIVATE, fd, off_start);
683 if (map==MAP_FAILED) goto error;
685 dso->map_len = map_len;
686 /* If the loaded file is not relocatable and the requested address is
687 * not available, then the load operation must fail. */
688 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
692 base = map - addr_min;
695 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
696 if (ph->p_type != PT_LOAD) continue;
697 /* Check if the programs headers are in this load segment, and
698 * if so, record the address for use by dl_iterate_phdr. */
699 if (!dso->phdr && eh->e_phoff >= ph->p_offset
700 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
701 dso->phdr = (void *)(base + ph->p_vaddr
702 + (eh->e_phoff-ph->p_offset));
703 dso->phnum = eh->e_phnum;
704 dso->phentsize = eh->e_phentsize;
706 /* Reuse the existing mapping for the lowest-address LOAD */
707 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT)
709 this_min = ph->p_vaddr & -PAGE_SIZE;
710 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
711 off_start = ph->p_offset & -PAGE_SIZE;
712 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
713 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
714 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
715 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
717 if (ph->p_memsz > ph->p_filesz) {
718 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
719 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
720 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
721 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)
725 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
726 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
727 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
734 dso->dynv = laddr(dso, dyn);
735 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
741 if (map!=MAP_FAILED) unmap_library(dso);
746 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
751 s += strspn(s, ":\n");
752 l = strcspn(s, ":\n");
753 if (l-1 >= INT_MAX) return -1;
754 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
755 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
763 /* Any negative value but -1 will inhibit
764 * futher path search. */
772 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
775 const char *s, *t, *origin;
777 if (p->rpath || !p->rpath_orig) return 0;
778 if (!strchr(p->rpath_orig, '$')) {
779 p->rpath = p->rpath_orig;
784 while ((t=strchr(s, '$'))) {
785 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
790 if (n > SSIZE_MAX/PATH_MAX) return 0;
792 if (p->kernel_mapped) {
793 /* $ORIGIN searches cannot be performed for the main program
794 * when it is suid/sgid/AT_SECURE. This is because the
795 * pathname is under the control of the caller of execve.
796 * For libraries, however, $ORIGIN can be processed safely
797 * since the library's pathname came from a trusted source
798 * (either system paths or a call to dlopen). */
801 l = readlink("/proc/self/exe", buf, buf_size);
802 if (l == -1) switch (errno) {
817 t = strrchr(origin, '/');
821 /* Normally p->name will always be an absolute or relative
822 * pathname containing at least one '/' character, but in the
823 * case where ldso was invoked as a command to execute a
824 * program in the working directory, app.name may not. Fix. */
828 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
829 if (libc.secure && *origin != '/')
831 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
832 if (!p->rpath) return -1;
836 while ((t=strchr(s, '$'))) {
839 memcpy(d, origin, l);
841 /* It was determined previously that the '$' is followed
842 * either by "ORIGIN" or "{ORIGIN}". */
843 s = t + 7 + 2*(t[1]=='{');
849 static void decode_dyn(struct dso *p)
852 decode_vec(p->dynv, dyn, DYN_CNT);
853 p->syms = laddr(p, dyn[DT_SYMTAB]);
854 p->strings = laddr(p, dyn[DT_STRTAB]);
855 if (dyn[0]&(1<<DT_HASH))
856 p->hashtab = laddr(p, dyn[DT_HASH]);
857 if (dyn[0]&(1<<DT_RPATH))
858 p->rpath_orig = p->strings + dyn[DT_RPATH];
859 if (dyn[0]&(1<<DT_RUNPATH))
860 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
861 if (dyn[0]&(1<<DT_PLTGOT))
862 p->got = laddr(p, dyn[DT_PLTGOT]);
863 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
864 p->ghashtab = laddr(p, *dyn);
865 if (search_vec(p->dynv, dyn, DT_VERSYM))
866 p->versym = laddr(p, *dyn);
869 static size_t count_syms(struct dso *p)
871 if (p->hashtab) return p->hashtab[1];
874 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
876 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
877 if (buckets[i] > nsym)
881 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
883 while (!(*hashval++ & 1));
888 static void *dl_mmap(size_t n)
891 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
893 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
895 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
897 return p == MAP_FAILED ? 0 : p;
900 static void makefuncdescs(struct dso *p)
902 static int self_done;
903 size_t nsym = count_syms(p);
904 size_t i, size = nsym * sizeof(*p->funcdescs);
907 p->funcdescs = dl_mmap(size);
910 p->funcdescs = malloc(size);
913 if (!runtime) a_crash();
914 error("Error allocating function descriptors for %s", p->name);
915 longjmp(*rtld_fail, 1);
917 for (i=0; i<nsym; i++) {
918 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
919 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
920 p->funcdescs[i].got = p->got;
922 p->funcdescs[i].addr = 0;
923 p->funcdescs[i].got = 0;
928 static struct dso *load_library(const char *name, struct dso *needed_by)
930 char buf[2*NAME_MAX+2];
931 const char *pathname;
933 struct dso *p, temp_dso = {0};
945 /* Catch and block attempts to reload the implementation itself */
946 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
947 static const char reserved[] =
948 "c.pthread.rt.m.dl.util.xnet.";
949 const char *rp, *next;
950 for (rp=reserved; *rp; rp=next) {
951 next = strchr(rp, '.') + 1;
952 if (strncmp(name+3, rp, next-rp) == 0)
957 /* Track which names have been resolved
958 * and only report each one once. */
959 static unsigned reported;
960 unsigned mask = 1U<<(rp-reserved);
961 if (!(reported & mask)) {
963 dprintf(1, "\t%s => %s (%p)\n",
971 if (!strcmp(name, ldso.name)) is_self = 1;
980 if (strchr(name, '/')) {
982 fd = open(name, O_RDONLY|O_CLOEXEC);
984 /* Search for the name to see if it's already loaded */
985 for (p=head->next; p; p=p->next) {
986 if (p->shortname && !strcmp(p->shortname, name)) {
990 if (strlen(name) > NAME_MAX) return 0;
992 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
993 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
994 if (fixup_rpath(p, buf, sizeof buf) < 0)
995 fd = -2; /* Inhibit further search. */
997 fd = path_open(name, p->rpath, buf, sizeof buf);
1003 if (ldso.name[0]=='/') {
1005 for (s=t=z=ldso.name; *s; s++)
1006 if (*s=='/') z=t, t=s;
1007 prefix_len = z-ldso.name;
1008 if (prefix_len < PATH_MAX)
1015 char etc_ldso_path[prefix_len + 1
1016 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1017 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1018 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1019 (int)prefix_len, prefix);
1020 FILE *f = fopen(etc_ldso_path, "rbe");
1022 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1027 } else if (errno != ENOENT) {
1031 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1032 fd = path_open(name, sys_path, buf, sizeof buf);
1036 if (fd < 0) return 0;
1037 if (fstat(fd, &st) < 0) {
1041 for (p=head->next; p; p=p->next) {
1042 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1043 /* If this library was previously loaded with a
1044 * pathname but a search found the same inode,
1045 * setup its shortname so it can be found by name. */
1046 if (!p->shortname && pathname != name)
1047 p->shortname = strrchr(p->name, '/')+1;
1052 map = noload ? 0 : map_library(fd, &temp_dso);
1056 /* Avoid the danger of getting two versions of libc mapped into the
1057 * same process when an absolute pathname was used. The symbols
1058 * checked are chosen to catch both musl and glibc, and to avoid
1059 * false positives from interposition-hack libraries. */
1060 decode_dyn(&temp_dso);
1061 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1062 find_sym(&temp_dso, "stdin", 1).sym) {
1063 unmap_library(&temp_dso);
1064 return load_library("libc.so", needed_by);
1066 /* Past this point, if we haven't reached runtime yet, ldso has
1067 * committed either to use the mapped library or to abort execution.
1068 * Unmapping is not possible, so we can safely reclaim gaps. */
1069 if (!runtime) reclaim_gaps(&temp_dso);
1071 /* Allocate storage for the new DSO. When there is TLS, this
1072 * storage must include a reservation for all pre-existing
1073 * threads to obtain copies of both the new TLS, and an
1074 * extended DTV capable of storing an additional slot for
1075 * the newly-loaded DSO. */
1076 alloc_size = sizeof *p + strlen(pathname) + 1;
1077 if (runtime && temp_dso.tls.image) {
1078 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1079 + sizeof(void *) * (tls_cnt+3);
1080 n_th = libc.threads_minus_1 + 1;
1081 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1082 else alloc_size += n_th * per_th;
1084 p = calloc(1, alloc_size);
1086 unmap_library(&temp_dso);
1089 memcpy(p, &temp_dso, sizeof temp_dso);
1092 p->needed_by = needed_by;
1094 strcpy(p->name, pathname);
1095 /* Add a shortname only if name arg was not an explicit pathname. */
1096 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1098 p->tls_id = ++tls_cnt;
1099 tls_align = MAXP2(tls_align, p->tls.align);
1101 p->tls.offset = tls_offset + ( (tls_align-1) &
1102 -(tls_offset + (uintptr_t)p->tls.image) );
1103 tls_offset += p->tls.size;
1105 tls_offset += p->tls.size + p->tls.align - 1;
1106 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1108 p->tls.offset = tls_offset;
1110 p->new_dtv = (void *)(-sizeof(size_t) &
1111 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1112 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1113 if (tls_tail) tls_tail->next = &p->tls;
1114 else libc.tls_head = &p->tls;
1122 if (DL_FDPIC) makefuncdescs(p);
1124 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1129 static void load_deps(struct dso *p)
1132 struct dso ***deps = &p->deps, **tmp, *dep;
1133 for (; p; p=p->next) {
1134 for (i=0; p->dynv[i]; i+=2) {
1135 if (p->dynv[i] != DT_NEEDED) continue;
1136 dep = load_library(p->strings + p->dynv[i+1], p);
1138 error("Error loading shared library %s: %m (needed by %s)",
1139 p->strings + p->dynv[i+1], p->name);
1140 if (runtime) longjmp(*rtld_fail, 1);
1144 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1145 if (!tmp) longjmp(*rtld_fail, 1);
1152 if (!*deps) *deps = (struct dso **)&nodeps_dummy;
1155 static void load_preload(char *s)
1159 for (z=s; *z; s=z) {
1160 for ( ; *s && (isspace(*s) || *s==':'); s++);
1161 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1169 static void add_syms(struct dso *p)
1171 if (!p->syms_next && syms_tail != p) {
1172 syms_tail->syms_next = p;
1177 static void revert_syms(struct dso *old_tail)
1179 struct dso *p, *next;
1180 /* Chop off the tail of the list of dsos that participate in
1181 * the global symbol table, reverting them to RTLD_LOCAL. */
1182 for (p=old_tail; p; p=next) {
1183 next = p->syms_next;
1186 syms_tail = old_tail;
1189 static void do_mips_relocs(struct dso *p, size_t *got)
1191 size_t i, j, rel[2];
1192 unsigned char *base = p->base;
1193 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1197 while (i--) *got++ += (size_t)base;
1199 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1200 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1201 Sym *sym = p->syms + j;
1202 rel[0] = (unsigned char *)got - base;
1203 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1204 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1205 do_relocs(p, rel, sizeof rel, 2);
1209 static void reloc_all(struct dso *p)
1211 size_t dyn[DYN_CNT];
1212 for (; p; p=p->next) {
1213 if (p->relocated) continue;
1214 decode_vec(p->dynv, dyn, DYN_CNT);
1215 if (NEED_MIPS_GOT_RELOCS)
1216 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1217 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1218 2+(dyn[DT_PLTREL]==DT_RELA));
1219 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1220 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1222 if (head != &ldso && p->relro_start != p->relro_end &&
1223 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1224 && errno != ENOSYS) {
1225 error("Error relocating %s: RELRO protection failed: %m",
1227 if (runtime) longjmp(*rtld_fail, 1);
1234 static void kernel_mapped_dso(struct dso *p)
1236 size_t min_addr = -1, max_addr = 0, cnt;
1238 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1239 if (ph->p_type == PT_DYNAMIC) {
1240 p->dynv = laddr(p, ph->p_vaddr);
1241 } else if (ph->p_type == PT_GNU_RELRO) {
1242 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1243 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1245 if (ph->p_type != PT_LOAD) continue;
1246 if (ph->p_vaddr < min_addr)
1247 min_addr = ph->p_vaddr;
1248 if (ph->p_vaddr+ph->p_memsz > max_addr)
1249 max_addr = ph->p_vaddr+ph->p_memsz;
1251 min_addr &= -PAGE_SIZE;
1252 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1253 p->map = p->base + min_addr;
1254 p->map_len = max_addr - min_addr;
1255 p->kernel_mapped = 1;
1258 void __libc_exit_fini()
1261 size_t dyn[DYN_CNT];
1262 for (p=fini_head; p; p=p->fini_next) {
1263 if (!p->constructed) continue;
1264 decode_vec(p->dynv, dyn, DYN_CNT);
1265 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1266 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1267 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1268 while (n--) ((void (*)(void))*--fn)();
1270 #ifndef NO_LEGACY_INITFINI
1271 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1272 fpaddr(p, dyn[DT_FINI])();
1277 static void do_init_fini(struct dso *p)
1279 size_t dyn[DYN_CNT];
1280 int need_locking = libc.threads_minus_1;
1281 /* Allow recursive calls that arise when a library calls
1282 * dlopen from one of its constructors, but block any
1283 * other threads until all ctors have finished. */
1284 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1285 for (; p; p=p->prev) {
1286 if (p->constructed) continue;
1288 decode_vec(p->dynv, dyn, DYN_CNT);
1289 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1290 p->fini_next = fini_head;
1293 #ifndef NO_LEGACY_INITFINI
1294 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1295 fpaddr(p, dyn[DT_INIT])();
1297 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1298 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1299 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1300 while (n--) ((void (*)(void))*fn++)();
1302 if (!need_locking && libc.threads_minus_1) {
1304 pthread_mutex_lock(&init_fini_lock);
1307 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1310 void __libc_start_init(void)
1315 static void dl_debug_state(void)
1319 weak_alias(dl_debug_state, _dl_debug_state);
1321 void __init_tls(size_t *auxv)
1325 __attribute__((__visibility__("hidden")))
1326 void *__tls_get_new(tls_mod_off_t *v)
1328 pthread_t self = __pthread_self();
1330 /* Block signals to make accessing new TLS async-signal-safe */
1332 __block_all_sigs(&set);
1333 if (v[0]<=(size_t)self->dtv[0]) {
1334 __restore_sigs(&set);
1335 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1338 /* This is safe without any locks held because, if the caller
1339 * is able to request the Nth entry of the DTV, the DSO list
1340 * must be valid at least that far out and it was synchronized
1341 * at program startup or by an already-completed call to dlopen. */
1343 for (p=head; p->tls_id != v[0]; p=p->next);
1345 /* Get new DTV space from new DSO if needed */
1346 if (v[0] > (size_t)self->dtv[0]) {
1347 void **newdtv = p->new_dtv +
1348 (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
1349 memcpy(newdtv, self->dtv,
1350 ((size_t)self->dtv[0]+1) * sizeof(void *));
1351 newdtv[0] = (void *)v[0];
1352 self->dtv = self->dtv_copy = newdtv;
1355 /* Get new TLS memory from all new DSOs up to the requested one */
1357 for (p=head; ; p=p->next) {
1358 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1359 mem = p->new_tls + (p->tls.size + p->tls.align)
1360 * a_fetch_add(&p->new_tls_idx,1);
1361 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1363 self->dtv[p->tls_id] = mem;
1364 memcpy(mem, p->tls.image, p->tls.len);
1365 if (p->tls_id == v[0]) break;
1367 __restore_sigs(&set);
1368 return mem + v[1] + DTP_OFFSET;
1371 static void update_tls_size()
1373 libc.tls_cnt = tls_cnt;
1374 libc.tls_align = tls_align;
1375 libc.tls_size = ALIGN(
1376 (1+tls_cnt) * sizeof(void *) +
1378 sizeof(struct pthread) +
1383 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1384 * following stage 2 and stage 3 functions via primitive symbolic lookup
1385 * since it does not have access to their addresses to begin with. */
1387 /* Stage 2 of the dynamic linker is called after relative relocations
1388 * have been processed. It can make function calls to static functions
1389 * and access string literals and static data, but cannot use extern
1390 * symbols. Its job is to perform symbolic relocations on the dynamic
1391 * linker itself, but some of the relocations performed may need to be
1392 * replaced later due to copy relocations in the main program. */
1394 __attribute__((__visibility__("hidden")))
1395 void __dls2(unsigned char *base, size_t *sp)
1398 void *p1 = (void *)sp[-2];
1399 void *p2 = (void *)sp[-1];
1401 size_t *auxv, aux[AUX_CNT];
1402 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1403 decode_vec(auxv, aux, AUX_CNT);
1404 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1405 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1407 app_loadmap = p2 ? p1 : 0;
1408 ldso.loadmap = p2 ? p2 : p1;
1409 ldso.base = laddr(&ldso, 0);
1413 Ehdr *ehdr = (void *)ldso.base;
1414 ldso.name = ldso.shortname = "libc.so";
1415 ldso.phnum = ehdr->e_phnum;
1416 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1417 ldso.phentsize = ehdr->e_phentsize;
1418 kernel_mapped_dso(&ldso);
1421 if (DL_FDPIC) makefuncdescs(&ldso);
1423 /* Prepare storage for to save clobbered REL addends so they
1424 * can be reused in stage 3. There should be very few. If
1425 * something goes wrong and there are a huge number, abort
1426 * instead of risking stack overflow. */
1427 size_t dyn[DYN_CNT];
1428 decode_vec(ldso.dynv, dyn, DYN_CNT);
1429 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1430 size_t rel_size = dyn[DT_RELSZ];
1431 size_t symbolic_rel_cnt = 0;
1432 apply_addends_to = rel;
1433 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1434 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1435 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1436 size_t addends[symbolic_rel_cnt+1];
1437 saved_addends = addends;
1444 /* Call dynamic linker stage-3, __dls3, looking it up
1445 * symbolically as a barrier against moving the address
1446 * load across the above relocation processing. */
1447 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1448 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1449 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1452 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1453 * fully functional. Its job is to load (if not already loaded) and
1454 * process dependencies and relocations for the main application and
1455 * transfer control to its entry point. */
1457 _Noreturn void __dls3(size_t *sp)
1459 static struct dso app, vdso;
1460 size_t aux[AUX_CNT], *auxv;
1462 char *env_preload=0;
1463 char *replace_argv0=0;
1466 char **argv = (void *)(sp+1);
1467 char **argv_orig = argv;
1468 char **envp = argv+argc+1;
1470 /* Find aux vector just past environ[] and use it to initialize
1471 * global data that may be needed before we can make syscalls. */
1473 for (i=argc+1; argv[i]; i++);
1474 libc.auxv = auxv = (void *)(argv+i+1);
1475 decode_vec(auxv, aux, AUX_CNT);
1476 __hwcap = aux[AT_HWCAP];
1477 libc.page_size = aux[AT_PAGESZ];
1478 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1479 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1481 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1482 * use during dynamic linking. If possible it will also serve as the
1483 * thread pointer at runtime. */
1484 libc.tls_size = sizeof builtin_tls;
1485 libc.tls_align = tls_align;
1486 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1490 /* Only trust user/env if kernel says we're not suid/sgid */
1492 env_path = getenv("LD_LIBRARY_PATH");
1493 env_preload = getenv("LD_PRELOAD");
1496 /* If the main program was already loaded by the kernel,
1497 * AT_PHDR will point to some location other than the dynamic
1498 * linker's program headers. */
1499 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1500 size_t interp_off = 0;
1501 size_t tls_image = 0;
1502 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1503 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1504 app.phnum = aux[AT_PHNUM];
1505 app.phentsize = aux[AT_PHENT];
1506 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1507 if (phdr->p_type == PT_PHDR)
1508 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1509 else if (phdr->p_type == PT_INTERP)
1510 interp_off = (size_t)phdr->p_vaddr;
1511 else if (phdr->p_type == PT_TLS) {
1512 tls_image = phdr->p_vaddr;
1513 app.tls.len = phdr->p_filesz;
1514 app.tls.size = phdr->p_memsz;
1515 app.tls.align = phdr->p_align;
1518 if (DL_FDPIC) app.loadmap = app_loadmap;
1519 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1520 if (interp_off) ldso.name = laddr(&app, interp_off);
1521 if ((aux[0] & (1UL<<AT_EXECFN))
1522 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1523 app.name = (char *)aux[AT_EXECFN];
1526 kernel_mapped_dso(&app);
1529 char *ldname = argv[0];
1530 size_t l = strlen(ldname);
1531 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1533 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1534 char *opt = argv[0]+2;
1535 *argv++ = (void *)-1;
1538 } else if (!memcmp(opt, "list", 5)) {
1540 } else if (!memcmp(opt, "library-path", 12)) {
1541 if (opt[12]=='=') env_path = opt+13;
1542 else if (opt[12]) *argv = 0;
1543 else if (*argv) env_path = *argv++;
1544 } else if (!memcmp(opt, "preload", 7)) {
1545 if (opt[7]=='=') env_preload = opt+8;
1546 else if (opt[7]) *argv = 0;
1547 else if (*argv) env_preload = *argv++;
1548 } else if (!memcmp(opt, "argv0", 5)) {
1549 if (opt[5]=='=') replace_argv0 = opt+6;
1550 else if (opt[5]) *argv = 0;
1551 else if (*argv) replace_argv0 = *argv++;
1556 argv[-1] = (void *)(argc - (argv-argv_orig));
1558 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1560 "Dynamic Program Loader\n"
1561 "Usage: %s [options] [--] pathname%s\n",
1562 __libc_get_version(), ldname,
1563 ldd_mode ? "" : " [args]");
1566 fd = open(argv[0], O_RDONLY);
1568 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1571 Ehdr *ehdr = (void *)map_library(fd, &app);
1573 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1579 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1580 /* Find the name that would have been used for the dynamic
1581 * linker had ldd not taken its place. */
1583 for (i=0; i<app.phnum; i++) {
1584 if (app.phdr[i].p_type == PT_INTERP)
1585 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1587 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1591 libc.tls_head = tls_tail = &app.tls;
1592 app.tls_id = tls_cnt = 1;
1595 tls_offset = app.tls.size
1596 + ( -((uintptr_t)app.tls.image + app.tls.size)
1597 & (app.tls.align-1) );
1599 tls_offset = app.tls.offset = app.tls.size
1600 + ( -((uintptr_t)app.tls.image + app.tls.size)
1601 & (app.tls.align-1) );
1603 tls_align = MAXP2(tls_align, app.tls.align);
1607 makefuncdescs(&app);
1609 app.loadmap = (void *)&app_dummy_loadmap;
1610 app.loadmap->nsegs = 1;
1611 app.loadmap->segs[0].addr = (size_t)app.map;
1612 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1614 app.loadmap->segs[0].p_memsz = app.map_len;
1616 argv[-3] = (void *)app.loadmap;
1619 /* Initial dso chain consists only of the app. */
1620 head = tail = syms_tail = &app;
1622 /* Donate unused parts of app and library mapping to malloc */
1624 reclaim_gaps(&ldso);
1626 /* Load preload/needed libraries, add symbols to global namespace. */
1627 if (env_preload) load_preload(env_preload);
1629 for (struct dso *p=head; p; p=p->next)
1632 /* Attach to vdso, if provided by the kernel, last so that it does
1633 * not become part of the global namespace. */
1634 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1635 Ehdr *ehdr = (void *)vdso_base;
1636 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1637 vdso.phnum = ehdr->e_phnum;
1638 vdso.phentsize = ehdr->e_phentsize;
1639 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1640 if (phdr->p_type == PT_DYNAMIC)
1641 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1642 if (phdr->p_type == PT_LOAD)
1643 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1646 vdso.shortname = "linux-gate.so.1";
1654 for (i=0; app.dynv[i]; i+=2) {
1655 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1656 app.dynv[i+1] = (size_t)&debug;
1657 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1658 size_t *ptr = (size_t *) app.dynv[i+1];
1659 *ptr = (size_t)&debug;
1663 /* The main program must be relocated LAST since it may contin
1664 * copy relocations which depend on libraries' relocations. */
1665 reloc_all(app.next);
1669 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1670 void *initial_tls = calloc(libc.tls_size, 1);
1672 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1673 argv[0], libc.tls_size);
1676 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1680 size_t tmp_tls_size = libc.tls_size;
1681 pthread_t self = __pthread_self();
1682 /* Temporarily set the tls size to the full size of
1683 * builtin_tls so that __copy_tls will use the same layout
1684 * as it did for before. Then check, just to be safe. */
1685 libc.tls_size = sizeof builtin_tls;
1686 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1687 libc.tls_size = tmp_tls_size;
1689 static_tls_cnt = tls_cnt;
1691 if (ldso_fail) _exit(127);
1692 if (ldd_mode) _exit(0);
1694 /* Switch to runtime mode: any further failures in the dynamic
1695 * linker are a reportable failure rather than a fatal startup
1700 debug.bp = dl_debug_state;
1702 debug.base = ldso.base;
1706 if (replace_argv0) argv[0] = replace_argv0;
1710 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1714 static void prepare_lazy(struct dso *p)
1716 size_t dyn[DYN_CNT], n, flags1=0;
1717 decode_vec(p->dynv, dyn, DYN_CNT);
1718 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1719 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1721 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1722 if (NEED_MIPS_GOT_RELOCS) {
1723 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1724 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1727 p->lazy = calloc(n, 3*sizeof(size_t));
1729 error("Error preparing lazy relocation for %s: %m", p->name);
1730 longjmp(*rtld_fail, 1);
1732 p->lazy_next = lazy_head;
1736 void *dlopen(const char *file, int mode)
1738 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1739 struct tls_module *orig_tls_tail;
1740 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1745 if (!file) return head;
1747 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1748 pthread_rwlock_wrlock(&lock);
1752 orig_tls_tail = tls_tail;
1753 orig_tls_cnt = tls_cnt;
1754 orig_tls_offset = tls_offset;
1755 orig_tls_align = tls_align;
1756 orig_lazy_head = lazy_head;
1757 orig_syms_tail = syms_tail;
1759 noload = mode & RTLD_NOLOAD;
1762 if (setjmp(*rtld_fail)) {
1763 /* Clean up anything new that was (partially) loaded */
1764 revert_syms(orig_syms_tail);
1765 for (p=orig_tail->next; p; p=next) {
1767 while (p->td_index) {
1768 void *tmp = p->td_index->next;
1773 if (p->rpath != p->rpath_orig)
1775 if (p->deps != &nodeps_dummy)
1780 if (!orig_tls_tail) libc.tls_head = 0;
1781 tls_tail = orig_tls_tail;
1782 if (tls_tail) tls_tail->next = 0;
1783 tls_cnt = orig_tls_cnt;
1784 tls_offset = orig_tls_offset;
1785 tls_align = orig_tls_align;
1786 lazy_head = orig_lazy_head;
1791 } else p = load_library(file, head);
1795 "Library %s is not already loaded" :
1796 "Error loading shared library %s: %m",
1801 /* First load handling */
1802 int first_load = !p->deps;
1805 if (!p->relocated && (mode & RTLD_LAZY)) {
1807 for (i=0; p->deps[i]; i++)
1808 if (!p->deps[i]->relocated)
1809 prepare_lazy(p->deps[i]);
1812 if (first_load || (mode & RTLD_GLOBAL)) {
1813 /* Make new symbols global, at least temporarily, so we can do
1814 * relocations. If not RTLD_GLOBAL, this is reverted below. */
1816 for (i=0; p->deps[i]; i++)
1817 add_syms(p->deps[i]);
1823 /* If RTLD_GLOBAL was not specified, undo any new additions
1824 * to the global symbol table. This is a nop if the library was
1825 * previously loaded and already global. */
1826 if (!(mode & RTLD_GLOBAL))
1827 revert_syms(orig_syms_tail);
1829 /* Processing of deferred lazy relocations must not happen until
1830 * the new libraries are committed; otherwise we could end up with
1831 * relocations resolved to symbol definitions that get removed. */
1840 pthread_rwlock_unlock(&lock);
1841 if (p) do_init_fini(orig_tail);
1842 pthread_setcancelstate(cs, 0);
1846 __attribute__((__visibility__("hidden")))
1847 int __dl_invalid_handle(void *h)
1850 for (p=head; p; p=p->next) if (h==p) return 0;
1851 error("Invalid library handle %p", (void *)h);
1855 static void *addr2dso(size_t a)
1859 if (DL_FDPIC) for (p=head; p; p=p->next) {
1861 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1864 for (p=head; p; p=p->next) {
1865 if (DL_FDPIC && p->loadmap) {
1866 for (i=0; i<p->loadmap->nsegs; i++) {
1867 if (a-p->loadmap->segs[i].p_vaddr
1868 < p->loadmap->segs[i].p_memsz)
1872 if (a-(size_t)p->map < p->map_len)
1879 void *__tls_get_addr(tls_mod_off_t *);
1881 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1884 uint32_t h = 0, gh = 0, *ght;
1886 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1887 if (p == RTLD_DEFAULT) {
1889 } else if (p == RTLD_NEXT) {
1890 p = addr2dso((size_t)ra);
1894 struct symdef def = find_sym(p, s, 0);
1895 if (!def.sym) goto failed;
1896 if ((def.sym->st_info&0xf) == STT_TLS)
1897 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value});
1898 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1899 return def.dso->funcdescs + (def.sym - def.dso->syms);
1900 return laddr(def.dso, def.sym->st_value);
1902 if (__dl_invalid_handle(p))
1904 if ((ght = p->ghashtab)) {
1906 sym = gnu_lookup(gh, ght, p, s);
1909 sym = sysv_lookup(s, h, p);
1911 if (sym && (sym->st_info&0xf) == STT_TLS)
1912 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value});
1913 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1914 return p->funcdescs + (sym - p->syms);
1915 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1916 return laddr(p, sym->st_value);
1917 for (i=0; p->deps[i]; i++) {
1918 if ((ght = p->deps[i]->ghashtab)) {
1919 if (!gh) gh = gnu_hash(s);
1920 sym = gnu_lookup(gh, ght, p->deps[i], s);
1922 if (!h) h = sysv_hash(s);
1923 sym = sysv_lookup(s, h, p->deps[i]);
1925 if (sym && (sym->st_info&0xf) == STT_TLS)
1926 return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value});
1927 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1928 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1929 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1930 return laddr(p->deps[i], sym->st_value);
1933 error("Symbol not found: %s", s);
1937 int dladdr(const void *addr, Dl_info *info)
1945 pthread_rwlock_rdlock(&lock);
1946 p = addr2dso((size_t)addr);
1947 pthread_rwlock_unlock(&lock);
1952 strings = p->strings;
1953 nsym = count_syms(p);
1956 size_t idx = ((size_t)addr-(size_t)p->funcdescs)
1957 / sizeof(*p->funcdescs);
1958 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1959 best = p->funcdescs + idx;
1960 bestsym = sym + idx;
1964 if (!best) for (; nsym; nsym--, sym++) {
1966 && (1<<(sym->st_info&0xf) & OK_TYPES)
1967 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1968 void *symaddr = laddr(p, sym->st_value);
1969 if (symaddr > addr || symaddr < best)
1973 if (addr == symaddr)
1978 if (!best) return 0;
1980 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
1981 best = p->funcdescs + (bestsym - p->syms);
1983 info->dli_fname = p->name;
1984 info->dli_fbase = p->map;
1985 info->dli_sname = strings + bestsym->st_name;
1986 info->dli_saddr = best;
1991 __attribute__((__visibility__("hidden")))
1992 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1995 pthread_rwlock_rdlock(&lock);
1996 res = do_dlsym(p, s, ra);
1997 pthread_rwlock_unlock(&lock);
2001 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2003 struct dso *current;
2004 struct dl_phdr_info info;
2006 for(current = head; current;) {
2007 info.dlpi_addr = (uintptr_t)current->base;
2008 info.dlpi_name = current->name;
2009 info.dlpi_phdr = current->phdr;
2010 info.dlpi_phnum = current->phnum;
2011 info.dlpi_adds = gencnt;
2013 info.dlpi_tls_modid = current->tls_id;
2014 info.dlpi_tls_data = current->tls.image;
2016 ret = (callback)(&info, sizeof (info), data);
2018 if (ret != 0) break;
2020 pthread_rwlock_rdlock(&lock);
2021 current = current->next;
2022 pthread_rwlock_unlock(&lock);
2027 __attribute__((__visibility__("hidden")))
2028 void __dl_vseterr(const char *, va_list);
2030 static void error(const char *fmt, ...)
2035 vdprintf(2, fmt, ap);
2041 __dl_vseterr(fmt, ap);