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;
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 int __init_tp(void *);
100 void __init_libc(char **, char *);
101 void *__copy_tls(unsigned char *);
103 __attribute__((__visibility__("hidden")))
104 const char *__libc_get_version(void);
106 static struct builtin_tls {
111 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
113 #define ADDEND_LIMIT 4096
114 static size_t *saved_addends, *apply_addends_to;
116 static struct dso ldso;
117 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
118 static char *env_path, *sys_path;
119 static unsigned long long gencnt;
122 static int ldso_fail;
124 static jmp_buf *rtld_fail;
125 static pthread_rwlock_t lock;
126 static struct debug debug;
127 static struct tls_module *tls_tail;
128 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
129 static size_t static_tls_cnt;
130 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
131 static struct fdpic_loadmap *app_loadmap;
132 static struct fdpic_dummy_loadmap app_dummy_loadmap;
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 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
162 laddr(p, v), (p)->got })
164 #define laddr(p, v) (void *)((p)->base + (v))
165 #define fpaddr(p, v) ((void (*)())laddr(p, v))
168 static void decode_vec(size_t *v, size_t *a, size_t cnt)
171 for (i=0; i<cnt; i++) a[i] = 0;
172 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
178 static int search_vec(size_t *v, size_t *r, size_t key)
180 for (; v[0]!=key; v+=2)
186 static uint32_t sysv_hash(const char *s0)
188 const unsigned char *s = (void *)s0;
194 return h & 0xfffffff;
197 static uint32_t gnu_hash(const char *s0)
199 const unsigned char *s = (void *)s0;
200 uint_fast32_t h = 5381;
206 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
209 Sym *syms = dso->syms;
210 Elf_Symndx *hashtab = dso->hashtab;
211 char *strings = dso->strings;
212 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
213 if ((!dso->versym || dso->versym[i] >= 0)
214 && (!strcmp(s, strings+syms[i].st_name)))
220 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
222 uint32_t nbuckets = hashtab[0];
223 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
224 uint32_t i = buckets[h1 % nbuckets];
228 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
230 for (h1 |= 1; ; i++) {
231 uint32_t h2 = *hashval++;
232 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
233 && !strcmp(s, dso->strings + dso->syms[i].st_name))
241 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
243 const size_t *bloomwords = (const void *)(hashtab+4);
244 size_t f = bloomwords[fofs & (hashtab[2]-1)];
245 if (!(f & fmask)) return 0;
247 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
248 if (!(f & 1)) return 0;
250 return gnu_lookup(h1, hashtab, dso, s);
253 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
254 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
256 #ifndef ARCH_SYM_REJECT_UND
257 #define ARCH_SYM_REJECT_UND(s) 0
260 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
262 uint32_t h = 0, gh, gho, *ght;
264 struct symdef def = {0};
265 for (; dso; dso=dso->syms_next) {
267 if ((ght = dso->ghashtab)) {
270 int maskbits = 8 * sizeof ghm;
272 ghm = 1ul << gh % maskbits;
274 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
276 if (!h) h = sysv_hash(s);
277 sym = sysv_lookup(s, h, dso);
281 if (need_def || (sym->st_info&0xf) == STT_TLS
282 || ARCH_SYM_REJECT_UND(sym))
285 if ((sym->st_info&0xf) != STT_TLS)
287 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
288 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
296 __attribute__((__visibility__("hidden")))
297 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
299 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
301 unsigned char *base = dso->base;
302 Sym *syms = dso->syms;
303 char *strings = dso->strings;
314 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
317 /* Only ldso's REL table needs addend saving/reuse. */
318 if (rel == apply_addends_to)
323 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
324 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
325 type = R_TYPE(rel[1]);
326 if (type == REL_NONE) continue;
327 reloc_addr = laddr(dso, rel[0]);
331 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
333 } else if (reuse_addends) {
334 /* Save original addend in stage 2 where the dso
335 * chain consists of just ldso; otherwise read back
336 * saved addend since the inline one was clobbered. */
338 saved_addends[save_slot] = *reloc_addr;
339 addend = saved_addends[save_slot++];
341 addend = *reloc_addr;
344 sym_index = R_SYM(rel[1]);
346 sym = syms + sym_index;
347 name = strings + sym->st_name;
348 ctx = type==REL_COPY ? head->syms_next : head;
349 def = (sym->st_info&0xf) == STT_SECTION
350 ? (struct symdef){ .dso = dso, .sym = sym }
351 : find_sym(ctx, name, type==REL_PLT);
352 if (!def.sym && (sym->st_shndx != SHN_UNDEF
353 || sym->st_info>>4 != STB_WEAK)) {
354 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
355 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
356 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
357 dso->lazy[3*dso->lazy_cnt+2] = addend;
361 error("Error relocating %s: %s: symbol not found",
363 if (runtime) longjmp(*rtld_fail, 1);
372 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
373 tls_val = def.sym ? def.sym->st_value : 0;
379 addend -= (size_t)reloc_addr;
383 *reloc_addr = sym_val + addend;
386 *reloc_addr = (size_t)base + addend;
389 if (sym) *reloc_addr = sym_val + addend;
390 else *reloc_addr = (size_t)base + addend;
393 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
396 *(uint32_t *)reloc_addr = sym_val + addend
397 - (size_t)reloc_addr;
400 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
401 + (def.sym - def.dso->syms)) : 0;
403 case REL_FUNCDESC_VAL:
404 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
405 else *reloc_addr = sym_val;
406 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
409 *reloc_addr = def.dso->tls_id;
412 *reloc_addr = tls_val + addend - DTP_OFFSET;
416 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
420 *reloc_addr = tls_val - def.dso->tls.offset + addend;
423 *reloc_addr = def.dso->tls.offset - tls_val + addend;
427 if (stride<3) addend = reloc_addr[1];
428 if (runtime && def.dso->tls_id >= static_tls_cnt) {
429 struct td_index *new = malloc(sizeof *new);
432 "Error relocating %s: cannot allocate TLSDESC for %s",
433 dso->name, sym ? name : "(local)" );
434 longjmp(*rtld_fail, 1);
436 new->next = dso->td_index;
438 new->args[0] = def.dso->tls_id;
439 new->args[1] = tls_val + addend;
440 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
441 reloc_addr[1] = (size_t)new;
443 reloc_addr[0] = (size_t)__tlsdesc_static;
445 reloc_addr[1] = tls_val + def.dso->tls.offset
448 reloc_addr[1] = tls_val - def.dso->tls.offset
454 error("Error relocating %s: unsupported relocation type %d",
456 if (runtime) longjmp(*rtld_fail, 1);
462 static void redo_lazy_relocs()
464 struct dso *p = lazy_head, *next;
468 size_t size = p->lazy_cnt*3*sizeof(size_t);
470 do_relocs(p, p->lazy, size, 3);
472 p->lazy_next = lazy_head;
482 /* A huge hack: to make up for the wastefulness of shared libraries
483 * needing at least a page of dirty memory even if they have no global
484 * data, we reclaim the gaps at the beginning and end of writable maps
485 * and "donate" them to the heap by setting up minimal malloc
486 * structures and then freeing them. */
488 static void reclaim(struct dso *dso, size_t start, size_t end)
491 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
492 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
493 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
494 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
495 if (start>end || end-start < 4*sizeof(size_t)) return;
496 a = laddr(dso, start);
499 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
504 static void reclaim_gaps(struct dso *dso)
506 Phdr *ph = dso->phdr;
507 size_t phcnt = dso->phnum;
509 if (DL_FDPIC) return; // FIXME
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 /* Reuse the existing mapping for the lowest-address LOAD */
705 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT)
707 this_min = ph->p_vaddr & -PAGE_SIZE;
708 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
709 off_start = ph->p_offset & -PAGE_SIZE;
710 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
711 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
712 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
713 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
715 if (ph->p_memsz > ph->p_filesz) {
716 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
717 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
718 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
719 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)
723 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
724 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
725 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
732 dso->dynv = laddr(dso, dyn);
733 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
734 if (!runtime) reclaim_gaps(dso);
740 if (map!=MAP_FAILED) unmap_library(dso);
745 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
750 s += strspn(s, ":\n");
751 l = strcspn(s, ":\n");
752 if (l-1 >= INT_MAX) return -1;
753 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
754 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
762 /* Any negative value but -1 will inhibit
763 * futher path search. */
771 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
774 const char *s, *t, *origin;
776 if (p->rpath || !p->rpath_orig) return 0;
777 if (!strchr(p->rpath_orig, '$')) {
778 p->rpath = p->rpath_orig;
783 while ((t=strchr(s, '$'))) {
784 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
789 if (n > SSIZE_MAX/PATH_MAX) return 0;
791 if (p->kernel_mapped) {
792 /* $ORIGIN searches cannot be performed for the main program
793 * when it is suid/sgid/AT_SECURE. This is because the
794 * pathname is under the control of the caller of execve.
795 * For libraries, however, $ORIGIN can be processed safely
796 * since the library's pathname came from a trusted source
797 * (either system paths or a call to dlopen). */
800 l = readlink("/proc/self/exe", buf, buf_size);
801 if (l == -1) switch (errno) {
816 t = strrchr(origin, '/');
817 l = t ? t-origin : 0;
818 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
819 if (!p->rpath) return -1;
823 while ((t=strchr(s, '$'))) {
826 memcpy(d, origin, l);
828 /* It was determined previously that the '$' is followed
829 * either by "ORIGIN" or "{ORIGIN}". */
830 s = t + 7 + 2*(t[1]=='{');
836 static void decode_dyn(struct dso *p)
839 decode_vec(p->dynv, dyn, DYN_CNT);
840 p->syms = laddr(p, dyn[DT_SYMTAB]);
841 p->strings = laddr(p, dyn[DT_STRTAB]);
842 if (dyn[0]&(1<<DT_HASH))
843 p->hashtab = laddr(p, dyn[DT_HASH]);
844 if (dyn[0]&(1<<DT_RPATH))
845 p->rpath_orig = p->strings + dyn[DT_RPATH];
846 if (dyn[0]&(1<<DT_RUNPATH))
847 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
848 if (dyn[0]&(1<<DT_PLTGOT))
849 p->got = laddr(p, dyn[DT_PLTGOT]);
850 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
851 p->ghashtab = laddr(p, *dyn);
852 if (search_vec(p->dynv, dyn, DT_VERSYM))
853 p->versym = laddr(p, *dyn);
856 static size_t count_syms(struct dso *p)
858 if (p->hashtab) return p->hashtab[1];
861 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
863 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
864 if (buckets[i] > nsym)
868 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
870 while (!(*hashval++ & 1));
875 static void *dl_mmap(size_t n)
878 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
880 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
882 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
884 return p == MAP_FAILED ? 0 : p;
887 static void makefuncdescs(struct dso *p)
889 static int self_done;
890 size_t nsym = count_syms(p);
891 size_t i, size = nsym * sizeof(*p->funcdescs);
894 p->funcdescs = dl_mmap(size);
897 p->funcdescs = malloc(size);
900 if (!runtime) a_crash();
901 error("Error allocating function descriptors for %s", p->name);
902 longjmp(*rtld_fail, 1);
904 for (i=0; i<nsym; i++) {
905 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
906 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
907 p->funcdescs[i].got = p->got;
909 p->funcdescs[i].addr = 0;
910 p->funcdescs[i].got = 0;
915 static struct dso *load_library(const char *name, struct dso *needed_by)
917 char buf[2*NAME_MAX+2];
918 const char *pathname;
920 struct dso *p, temp_dso = {0};
932 /* Catch and block attempts to reload the implementation itself */
933 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
934 static const char reserved[] =
935 "c.pthread.rt.m.dl.util.xnet.";
936 const char *rp, *next;
937 for (rp=reserved; *rp; rp=next) {
938 next = strchr(rp, '.') + 1;
939 if (strncmp(name+3, rp, next-rp) == 0)
944 /* Track which names have been resolved
945 * and only report each one once. */
946 static unsigned reported;
947 unsigned mask = 1U<<(rp-reserved);
948 if (!(reported & mask)) {
950 dprintf(1, "\t%s => %s (%p)\n",
958 if (!strcmp(name, ldso.name)) is_self = 1;
967 if (strchr(name, '/')) {
969 fd = open(name, O_RDONLY|O_CLOEXEC);
971 /* Search for the name to see if it's already loaded */
972 for (p=head->next; p; p=p->next) {
973 if (p->shortname && !strcmp(p->shortname, name)) {
978 if (strlen(name) > NAME_MAX) return 0;
980 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
981 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
982 if (fixup_rpath(p, buf, sizeof buf) < 0)
983 fd = -2; /* Inhibit further search. */
985 fd = path_open(name, p->rpath, buf, sizeof buf);
991 if (ldso.name[0]=='/') {
993 for (s=t=z=ldso.name; *s; s++)
994 if (*s=='/') z=t, t=s;
995 prefix_len = z-ldso.name;
996 if (prefix_len < PATH_MAX)
1003 char etc_ldso_path[prefix_len + 1
1004 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1005 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1006 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1007 (int)prefix_len, prefix);
1008 FILE *f = fopen(etc_ldso_path, "rbe");
1010 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1015 } else if (errno != ENOENT) {
1019 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1020 fd = path_open(name, sys_path, buf, sizeof buf);
1024 if (fd < 0) return 0;
1025 if (fstat(fd, &st) < 0) {
1029 for (p=head->next; p; p=p->next) {
1030 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1031 /* If this library was previously loaded with a
1032 * pathname but a search found the same inode,
1033 * setup its shortname so it can be found by name. */
1034 if (!p->shortname && pathname != name)
1035 p->shortname = strrchr(p->name, '/')+1;
1041 map = noload ? 0 : map_library(fd, &temp_dso);
1045 /* Avoid the danger of getting two versions of libc mapped into the
1046 * same process when an absolute pathname was used. The symbols
1047 * checked are chosen to catch both musl and glibc, and to avoid
1048 * false positives from interposition-hack libraries. */
1049 decode_dyn(&temp_dso);
1050 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1051 find_sym(&temp_dso, "stdin", 1).sym) {
1052 unmap_library(&temp_dso);
1053 return load_library("libc.so", needed_by);
1056 /* Allocate storage for the new DSO. When there is TLS, this
1057 * storage must include a reservation for all pre-existing
1058 * threads to obtain copies of both the new TLS, and an
1059 * extended DTV capable of storing an additional slot for
1060 * the newly-loaded DSO. */
1061 alloc_size = sizeof *p + strlen(pathname) + 1;
1062 if (runtime && temp_dso.tls.image) {
1063 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1064 + sizeof(void *) * (tls_cnt+3);
1065 n_th = libc.threads_minus_1 + 1;
1066 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1067 else alloc_size += n_th * per_th;
1069 p = calloc(1, alloc_size);
1071 unmap_library(&temp_dso);
1074 memcpy(p, &temp_dso, sizeof temp_dso);
1078 p->needed_by = needed_by;
1080 strcpy(p->name, pathname);
1081 /* Add a shortname only if name arg was not an explicit pathname. */
1082 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1084 p->tls_id = ++tls_cnt;
1085 tls_align = MAXP2(tls_align, p->tls.align);
1087 p->tls.offset = tls_offset + ( (tls_align-1) &
1088 -(tls_offset + (uintptr_t)p->tls.image) );
1089 tls_offset += p->tls.size;
1091 tls_offset += p->tls.size + p->tls.align - 1;
1092 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1094 p->tls.offset = tls_offset;
1096 p->new_dtv = (void *)(-sizeof(size_t) &
1097 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1098 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1099 if (tls_tail) tls_tail->next = &p->tls;
1100 else libc.tls_head = &p->tls;
1108 if (DL_FDPIC) makefuncdescs(p);
1110 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1115 static void load_deps(struct dso *p)
1118 struct dso ***deps = &p->deps, **tmp, *dep;
1119 for (; p; p=p->next) {
1120 for (i=0; p->dynv[i]; i+=2) {
1121 if (p->dynv[i] != DT_NEEDED) continue;
1122 dep = load_library(p->strings + p->dynv[i+1], p);
1124 error("Error loading shared library %s: %m (needed by %s)",
1125 p->strings + p->dynv[i+1], p->name);
1126 if (runtime) longjmp(*rtld_fail, 1);
1130 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1131 if (!tmp) longjmp(*rtld_fail, 1);
1140 static void load_preload(char *s)
1144 for (z=s; *z; s=z) {
1145 for ( ; *s && (isspace(*s) || *s==':'); s++);
1146 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1154 static void add_syms(struct dso *p)
1156 if (!p->syms_next && syms_tail != p) {
1157 syms_tail->syms_next = p;
1162 static void revert_syms(struct dso *old_tail)
1164 struct dso *p, *next;
1165 /* Chop off the tail of the list of dsos that participate in
1166 * the global symbol table, reverting them to RTLD_LOCAL. */
1167 for (p=old_tail; p; p=next) {
1168 next = p->syms_next;
1171 syms_tail = old_tail;
1174 static void do_mips_relocs(struct dso *p, size_t *got)
1176 size_t i, j, rel[2];
1177 unsigned char *base = p->base;
1178 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1182 while (i--) *got++ += (size_t)base;
1184 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1185 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1186 Sym *sym = p->syms + j;
1187 rel[0] = (unsigned char *)got - base;
1188 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1189 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1190 do_relocs(p, rel, sizeof rel, 2);
1194 static void reloc_all(struct dso *p)
1196 size_t dyn[DYN_CNT];
1197 for (; p; p=p->next) {
1198 if (p->relocated) continue;
1199 decode_vec(p->dynv, dyn, DYN_CNT);
1200 if (NEED_MIPS_GOT_RELOCS)
1201 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1202 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1203 2+(dyn[DT_PLTREL]==DT_RELA));
1204 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1205 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1207 if (head != &ldso && p->relro_start != p->relro_end &&
1208 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1209 && errno != ENOSYS) {
1210 error("Error relocating %s: RELRO protection failed: %m",
1212 if (runtime) longjmp(*rtld_fail, 1);
1219 static void kernel_mapped_dso(struct dso *p)
1221 size_t min_addr = -1, max_addr = 0, cnt;
1223 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1224 if (ph->p_type == PT_DYNAMIC) {
1225 p->dynv = laddr(p, ph->p_vaddr);
1226 } else if (ph->p_type == PT_GNU_RELRO) {
1227 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1228 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1230 if (ph->p_type != PT_LOAD) continue;
1231 if (ph->p_vaddr < min_addr)
1232 min_addr = ph->p_vaddr;
1233 if (ph->p_vaddr+ph->p_memsz > max_addr)
1234 max_addr = ph->p_vaddr+ph->p_memsz;
1236 min_addr &= -PAGE_SIZE;
1237 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1238 p->map = p->base + min_addr;
1239 p->map_len = max_addr - min_addr;
1240 p->kernel_mapped = 1;
1243 void __libc_exit_fini()
1246 size_t dyn[DYN_CNT];
1247 for (p=fini_head; p; p=p->fini_next) {
1248 if (!p->constructed) continue;
1249 decode_vec(p->dynv, dyn, DYN_CNT);
1250 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1251 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1252 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1253 while (n--) ((void (*)(void))*--fn)();
1255 #ifndef NO_LEGACY_INITFINI
1256 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1257 fpaddr(p, dyn[DT_FINI])();
1262 static void do_init_fini(struct dso *p)
1264 size_t dyn[DYN_CNT];
1265 int need_locking = libc.threads_minus_1;
1266 /* Allow recursive calls that arise when a library calls
1267 * dlopen from one of its constructors, but block any
1268 * other threads until all ctors have finished. */
1269 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1270 for (; p; p=p->prev) {
1271 if (p->constructed) continue;
1273 decode_vec(p->dynv, dyn, DYN_CNT);
1274 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1275 p->fini_next = fini_head;
1278 #ifndef NO_LEGACY_INITFINI
1279 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1280 fpaddr(p, dyn[DT_INIT])();
1282 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1283 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1284 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1285 while (n--) ((void (*)(void))*fn++)();
1287 if (!need_locking && libc.threads_minus_1) {
1289 pthread_mutex_lock(&init_fini_lock);
1292 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1295 void __libc_start_init(void)
1300 static void dl_debug_state(void)
1304 weak_alias(dl_debug_state, _dl_debug_state);
1306 void __init_tls(size_t *auxv)
1310 __attribute__((__visibility__("hidden")))
1311 void *__tls_get_new(tls_mod_off_t *v)
1313 pthread_t self = __pthread_self();
1315 /* Block signals to make accessing new TLS async-signal-safe */
1317 __block_all_sigs(&set);
1318 if (v[0]<=(size_t)self->dtv[0]) {
1319 __restore_sigs(&set);
1320 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1323 /* This is safe without any locks held because, if the caller
1324 * is able to request the Nth entry of the DTV, the DSO list
1325 * must be valid at least that far out and it was synchronized
1326 * at program startup or by an already-completed call to dlopen. */
1328 for (p=head; p->tls_id != v[0]; p=p->next);
1330 /* Get new DTV space from new DSO if needed */
1331 if (v[0] > (size_t)self->dtv[0]) {
1332 void **newdtv = p->new_dtv +
1333 (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
1334 memcpy(newdtv, self->dtv,
1335 ((size_t)self->dtv[0]+1) * sizeof(void *));
1336 newdtv[0] = (void *)v[0];
1337 self->dtv = self->dtv_copy = newdtv;
1340 /* Get new TLS memory from all new DSOs up to the requested one */
1342 for (p=head; ; p=p->next) {
1343 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1344 mem = p->new_tls + (p->tls.size + p->tls.align)
1345 * a_fetch_add(&p->new_tls_idx,1);
1346 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1348 self->dtv[p->tls_id] = mem;
1349 memcpy(mem, p->tls.image, p->tls.len);
1350 if (p->tls_id == v[0]) break;
1352 __restore_sigs(&set);
1353 return mem + v[1] + DTP_OFFSET;
1356 static void update_tls_size()
1358 libc.tls_cnt = tls_cnt;
1359 libc.tls_align = tls_align;
1360 libc.tls_size = ALIGN(
1361 (1+tls_cnt) * sizeof(void *) +
1363 sizeof(struct pthread) +
1368 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1369 * following stage 2 and stage 3 functions via primitive symbolic lookup
1370 * since it does not have access to their addresses to begin with. */
1372 /* Stage 2 of the dynamic linker is called after relative relocations
1373 * have been processed. It can make function calls to static functions
1374 * and access string literals and static data, but cannot use extern
1375 * symbols. Its job is to perform symbolic relocations on the dynamic
1376 * linker itself, but some of the relocations performed may need to be
1377 * replaced later due to copy relocations in the main program. */
1379 __attribute__((__visibility__("hidden")))
1380 void __dls2(unsigned char *base, size_t *sp)
1383 void *p1 = (void *)sp[-2];
1384 void *p2 = (void *)sp[-1];
1386 size_t *auxv, aux[AUX_CNT];
1387 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1388 decode_vec(auxv, aux, AUX_CNT);
1389 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1390 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1392 app_loadmap = p2 ? p1 : 0;
1393 ldso.loadmap = p2 ? p2 : p1;
1394 ldso.base = laddr(&ldso, 0);
1398 Ehdr *ehdr = (void *)ldso.base;
1399 ldso.name = ldso.shortname = "libc.so";
1400 ldso.phnum = ehdr->e_phnum;
1401 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1402 ldso.phentsize = ehdr->e_phentsize;
1403 kernel_mapped_dso(&ldso);
1406 if (DL_FDPIC) makefuncdescs(&ldso);
1408 /* Prepare storage for to save clobbered REL addends so they
1409 * can be reused in stage 3. There should be very few. If
1410 * something goes wrong and there are a huge number, abort
1411 * instead of risking stack overflow. */
1412 size_t dyn[DYN_CNT];
1413 decode_vec(ldso.dynv, dyn, DYN_CNT);
1414 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1415 size_t rel_size = dyn[DT_RELSZ];
1416 size_t symbolic_rel_cnt = 0;
1417 apply_addends_to = rel;
1418 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1419 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1420 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1421 size_t addends[symbolic_rel_cnt+1];
1422 saved_addends = addends;
1429 /* Call dynamic linker stage-3, __dls3, looking it up
1430 * symbolically as a barrier against moving the address
1431 * load across the above relocation processing. */
1432 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1433 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1434 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1437 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1438 * fully functional. Its job is to load (if not already loaded) and
1439 * process dependencies and relocations for the main application and
1440 * transfer control to its entry point. */
1442 _Noreturn void __dls3(size_t *sp)
1444 static struct dso app, vdso;
1445 size_t aux[AUX_CNT], *auxv;
1447 char *env_preload=0;
1450 char **argv = (void *)(sp+1);
1451 char **argv_orig = argv;
1452 char **envp = argv+argc+1;
1454 /* Find aux vector just past environ[] and use it to initialize
1455 * global data that may be needed before we can make syscalls. */
1457 for (i=argc+1; argv[i]; i++);
1458 libc.auxv = auxv = (void *)(argv+i+1);
1459 decode_vec(auxv, aux, AUX_CNT);
1460 __hwcap = aux[AT_HWCAP];
1461 libc.page_size = aux[AT_PAGESZ];
1462 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1463 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1465 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1466 * use during dynamic linking. If possible it will also serve as the
1467 * thread pointer at runtime. */
1468 libc.tls_size = sizeof builtin_tls;
1469 libc.tls_align = tls_align;
1470 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1474 /* Only trust user/env if kernel says we're not suid/sgid */
1476 env_path = getenv("LD_LIBRARY_PATH");
1477 env_preload = getenv("LD_PRELOAD");
1480 /* If the main program was already loaded by the kernel,
1481 * AT_PHDR will point to some location other than the dynamic
1482 * linker's program headers. */
1483 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1484 size_t interp_off = 0;
1485 size_t tls_image = 0;
1486 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1487 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1488 app.phnum = aux[AT_PHNUM];
1489 app.phentsize = aux[AT_PHENT];
1490 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1491 if (phdr->p_type == PT_PHDR)
1492 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1493 else if (phdr->p_type == PT_INTERP)
1494 interp_off = (size_t)phdr->p_vaddr;
1495 else if (phdr->p_type == PT_TLS) {
1496 tls_image = phdr->p_vaddr;
1497 app.tls.len = phdr->p_filesz;
1498 app.tls.size = phdr->p_memsz;
1499 app.tls.align = phdr->p_align;
1502 if (DL_FDPIC) app.loadmap = app_loadmap;
1503 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1504 if (interp_off) ldso.name = laddr(&app, interp_off);
1505 if ((aux[0] & (1UL<<AT_EXECFN))
1506 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1507 app.name = (char *)aux[AT_EXECFN];
1510 kernel_mapped_dso(&app);
1513 char *ldname = argv[0];
1514 size_t l = strlen(ldname);
1515 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1517 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1518 char *opt = argv[0]+2;
1519 *argv++ = (void *)-1;
1522 } else if (!memcmp(opt, "list", 5)) {
1524 } else if (!memcmp(opt, "library-path", 12)) {
1525 if (opt[12]=='=') env_path = opt+13;
1526 else if (opt[12]) *argv = 0;
1527 else if (*argv) env_path = *argv++;
1528 } else if (!memcmp(opt, "preload", 7)) {
1529 if (opt[7]=='=') env_preload = opt+8;
1530 else if (opt[7]) *argv = 0;
1531 else if (*argv) env_preload = *argv++;
1536 argv[-1] = (void *)(argc - (argv-argv_orig));
1538 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1540 "Dynamic Program Loader\n"
1541 "Usage: %s [options] [--] pathname%s\n",
1542 __libc_get_version(), ldname,
1543 ldd_mode ? "" : " [args]");
1546 fd = open(argv[0], O_RDONLY);
1548 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1552 Ehdr *ehdr = (void *)map_library(fd, &app);
1554 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1561 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1562 /* Find the name that would have been used for the dynamic
1563 * linker had ldd not taken its place. */
1565 for (i=0; i<app.phnum; i++) {
1566 if (app.phdr[i].p_type == PT_INTERP)
1567 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1569 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1573 libc.tls_head = tls_tail = &app.tls;
1574 app.tls_id = tls_cnt = 1;
1577 tls_offset = app.tls.size
1578 + ( -((uintptr_t)app.tls.image + app.tls.size)
1579 & (app.tls.align-1) );
1581 tls_offset = app.tls.offset = app.tls.size
1582 + ( -((uintptr_t)app.tls.image + app.tls.size)
1583 & (app.tls.align-1) );
1585 tls_align = MAXP2(tls_align, app.tls.align);
1589 makefuncdescs(&app);
1591 app.loadmap = (void *)&app_dummy_loadmap;
1592 app.loadmap->nsegs = 1;
1593 app.loadmap->segs[0].addr = (size_t)app.map;
1594 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1596 app.loadmap->segs[0].p_memsz = app.map_len;
1598 argv[-3] = (void *)app.loadmap;
1601 /* Initial dso chain consists only of the app. */
1602 head = tail = syms_tail = &app;
1604 /* Donate unused parts of app and library mapping to malloc */
1606 reclaim_gaps(&ldso);
1608 /* Load preload/needed libraries, add symbols to global namespace. */
1609 if (env_preload) load_preload(env_preload);
1611 for (struct dso *p=head; p; p=p->next)
1614 /* Attach to vdso, if provided by the kernel, last so that it does
1615 * not become part of the global namespace. */
1616 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1617 Ehdr *ehdr = (void *)vdso_base;
1618 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1619 vdso.phnum = ehdr->e_phnum;
1620 vdso.phentsize = ehdr->e_phentsize;
1621 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1622 if (phdr->p_type == PT_DYNAMIC)
1623 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1624 if (phdr->p_type == PT_LOAD)
1625 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1628 vdso.shortname = "linux-gate.so.1";
1636 for (i=0; app.dynv[i]; i+=2) {
1637 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1638 app.dynv[i+1] = (size_t)&debug;
1639 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1640 size_t *ptr = (size_t *) app.dynv[i+1];
1641 *ptr = (size_t)&debug;
1645 /* The main program must be relocated LAST since it may contin
1646 * copy relocations which depend on libraries' relocations. */
1647 reloc_all(app.next);
1651 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1652 void *initial_tls = calloc(libc.tls_size, 1);
1654 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1655 argv[0], libc.tls_size);
1658 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1662 size_t tmp_tls_size = libc.tls_size;
1663 pthread_t self = __pthread_self();
1664 /* Temporarily set the tls size to the full size of
1665 * builtin_tls so that __copy_tls will use the same layout
1666 * as it did for before. Then check, just to be safe. */
1667 libc.tls_size = sizeof builtin_tls;
1668 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1669 libc.tls_size = tmp_tls_size;
1671 static_tls_cnt = tls_cnt;
1673 if (ldso_fail) _exit(127);
1674 if (ldd_mode) _exit(0);
1676 /* Switch to runtime mode: any further failures in the dynamic
1677 * linker are a reportable failure rather than a fatal startup
1682 debug.bp = dl_debug_state;
1684 debug.base = ldso.base;
1690 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1694 static void prepare_lazy(struct dso *p)
1696 size_t dyn[DYN_CNT], n, flags1=0;
1697 decode_vec(p->dynv, dyn, DYN_CNT);
1698 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1699 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1701 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1702 if (NEED_MIPS_GOT_RELOCS) {
1703 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1704 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1707 p->lazy = calloc(n, 3*sizeof(size_t));
1709 error("Error preparing lazy relocation for %s: %m", p->name);
1710 longjmp(*rtld_fail, 1);
1712 p->lazy_next = lazy_head;
1716 void *dlopen(const char *file, int mode)
1718 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1719 struct tls_module *orig_tls_tail;
1720 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1725 if (!file) return head;
1727 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1728 pthread_rwlock_wrlock(&lock);
1732 orig_tls_tail = tls_tail;
1733 orig_tls_cnt = tls_cnt;
1734 orig_tls_offset = tls_offset;
1735 orig_tls_align = tls_align;
1736 orig_lazy_head = lazy_head;
1737 orig_syms_tail = syms_tail;
1739 noload = mode & RTLD_NOLOAD;
1742 if (setjmp(*rtld_fail)) {
1743 /* Clean up anything new that was (partially) loaded */
1744 revert_syms(orig_syms_tail);
1745 for (p=orig_tail->next; p; p=next) {
1747 while (p->td_index) {
1748 void *tmp = p->td_index->next;
1753 if (p->rpath != p->rpath_orig)
1759 if (!orig_tls_tail) libc.tls_head = 0;
1760 tls_tail = orig_tls_tail;
1761 if (tls_tail) tls_tail->next = 0;
1762 tls_cnt = orig_tls_cnt;
1763 tls_offset = orig_tls_offset;
1764 tls_align = orig_tls_align;
1765 lazy_head = orig_lazy_head;
1770 } else p = load_library(file, head);
1774 "Library %s is not already loaded" :
1775 "Error loading shared library %s: %m",
1780 /* First load handling */
1781 if (!p->relocated) {
1783 if ((mode & RTLD_LAZY)) {
1785 if (p->deps) for (i=0; p->deps[i]; i++)
1786 if (!p->deps[i]->relocated)
1787 prepare_lazy(p->deps[i]);
1789 /* Make new symbols global, at least temporarily, so we can do
1790 * relocations. If not RTLD_GLOBAL, this is reverted below. */
1792 if (p->deps) for (i=0; p->deps[i]; i++)
1793 add_syms(p->deps[i]);
1797 /* If RTLD_GLOBAL was not specified, undo any new additions
1798 * to the global symbol table. This is a nop if the library was
1799 * previously loaded and already global. */
1800 if (!(mode & RTLD_GLOBAL))
1801 revert_syms(orig_syms_tail);
1803 /* Processing of deferred lazy relocations must not happen until
1804 * the new libraries are committed; otherwise we could end up with
1805 * relocations resolved to symbol definitions that get removed. */
1814 pthread_rwlock_unlock(&lock);
1815 if (p) do_init_fini(orig_tail);
1816 pthread_setcancelstate(cs, 0);
1820 __attribute__((__visibility__("hidden")))
1821 int __dl_invalid_handle(void *h)
1824 for (p=head; p; p=p->next) if (h==p) return 0;
1825 error("Invalid library handle %p", (void *)h);
1829 static void *addr2dso(size_t a)
1833 if (DL_FDPIC) for (p=head; p; p=p->next) {
1835 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1838 for (p=head; p; p=p->next) {
1839 if (DL_FDPIC && p->loadmap) {
1840 for (i=0; i<p->loadmap->nsegs; i++) {
1841 if (a-p->loadmap->segs[i].p_vaddr
1842 < p->loadmap->segs[i].p_memsz)
1846 if (a-(size_t)p->map < p->map_len)
1853 void *__tls_get_addr(tls_mod_off_t *);
1855 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1858 uint32_t h = 0, gh = 0, *ght;
1860 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1861 if (p == RTLD_DEFAULT) {
1863 } else if (p == RTLD_NEXT) {
1864 p = addr2dso((size_t)ra);
1868 struct symdef def = find_sym(p, s, 0);
1869 if (!def.sym) goto failed;
1870 if ((def.sym->st_info&0xf) == STT_TLS)
1871 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value});
1872 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1873 return def.dso->funcdescs + (def.sym - def.dso->syms);
1874 return laddr(def.dso, def.sym->st_value);
1876 if (__dl_invalid_handle(p))
1878 if ((ght = p->ghashtab)) {
1880 sym = gnu_lookup(gh, ght, p, s);
1883 sym = sysv_lookup(s, h, p);
1885 if (sym && (sym->st_info&0xf) == STT_TLS)
1886 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value});
1887 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1888 return p->funcdescs + (sym - p->syms);
1889 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1890 return laddr(p, sym->st_value);
1891 if (p->deps) for (i=0; p->deps[i]; i++) {
1892 if ((ght = p->deps[i]->ghashtab)) {
1893 if (!gh) gh = gnu_hash(s);
1894 sym = gnu_lookup(gh, ght, p->deps[i], s);
1896 if (!h) h = sysv_hash(s);
1897 sym = sysv_lookup(s, h, p->deps[i]);
1899 if (sym && (sym->st_info&0xf) == STT_TLS)
1900 return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value});
1901 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1902 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1903 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1904 return laddr(p->deps[i], sym->st_value);
1907 error("Symbol not found: %s", s);
1911 int dladdr(const void *addr, Dl_info *info)
1919 pthread_rwlock_rdlock(&lock);
1920 p = addr2dso((size_t)addr);
1921 pthread_rwlock_unlock(&lock);
1926 strings = p->strings;
1927 nsym = count_syms(p);
1930 size_t idx = ((size_t)addr-(size_t)p->funcdescs)
1931 / sizeof(*p->funcdescs);
1932 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1933 best = p->funcdescs + idx;
1934 bestsym = sym + idx;
1938 if (!best) for (; nsym; nsym--, sym++) {
1940 && (1<<(sym->st_info&0xf) & OK_TYPES)
1941 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1942 void *symaddr = laddr(p, sym->st_value);
1943 if (symaddr > addr || symaddr < best)
1947 if (addr == symaddr)
1952 if (!best) return 0;
1954 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
1955 best = p->funcdescs + (bestsym - p->syms);
1957 info->dli_fname = p->name;
1958 info->dli_fbase = p->base;
1959 info->dli_sname = strings + bestsym->st_name;
1960 info->dli_saddr = best;
1965 __attribute__((__visibility__("hidden")))
1966 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1969 pthread_rwlock_rdlock(&lock);
1970 res = do_dlsym(p, s, ra);
1971 pthread_rwlock_unlock(&lock);
1975 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1977 struct dso *current;
1978 struct dl_phdr_info info;
1980 for(current = head; current;) {
1981 info.dlpi_addr = (uintptr_t)current->base;
1982 info.dlpi_name = current->name;
1983 info.dlpi_phdr = current->phdr;
1984 info.dlpi_phnum = current->phnum;
1985 info.dlpi_adds = gencnt;
1987 info.dlpi_tls_modid = current->tls_id;
1988 info.dlpi_tls_data = current->tls.image;
1990 ret = (callback)(&info, sizeof (info), data);
1992 if (ret != 0) break;
1994 pthread_rwlock_rdlock(&lock);
1995 current = current->next;
1996 pthread_rwlock_unlock(&lock);
2001 __attribute__((__visibility__("hidden")))
2002 void __dl_vseterr(const char *, va_list);
2004 static void error(const char *fmt, ...)
2009 vdprintf(2, fmt, ap);
2015 __dl_vseterr(fmt, ap);