20 #include "pthread_impl.h"
24 static void error(const char *, ...);
28 #define MAXP2(a,b) (-(-(a)&-(b)))
29 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
41 struct td_index *next;
46 struct fdpic_loadmap *loadmap;
52 struct dso *next, *prev;
71 struct dso **deps, *needed_by;
72 char *rpath_orig, *rpath;
73 struct tls_module tls;
75 size_t relro_start, relro_end;
77 unsigned char *new_tls;
78 volatile int new_dtv_idx, new_tls_idx;
79 struct td_index *td_index;
80 struct dso *fini_next;
85 struct fdpic_loadmap *loadmap;
100 int __init_tp(void *);
101 void __init_libc(char **, char *);
102 void *__copy_tls(unsigned char *);
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;
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 static int dl_strcmp(const char *l, const char *r)
138 for (; *l==*r && *l; l++, r++);
139 return *(unsigned char *)l - *(unsigned char *)r;
141 #define strcmp(l,r) dl_strcmp(l,r)
143 /* Compute load address for a virtual address in a given dso. */
145 static void *laddr(const struct dso *p, size_t v)
148 if (!p->loadmap) return p->base + v;
149 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
150 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
152 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
153 laddr(p, v), (p)->got })
155 #define laddr(p, v) (void *)((p)->base + (v))
156 #define fpaddr(p, v) ((void (*)())laddr(p, v))
159 static void decode_vec(size_t *v, size_t *a, size_t cnt)
162 for (i=0; i<cnt; i++) a[i] = 0;
163 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
169 static int search_vec(size_t *v, size_t *r, size_t key)
171 for (; v[0]!=key; v+=2)
177 static uint32_t sysv_hash(const char *s0)
179 const unsigned char *s = (void *)s0;
185 return h & 0xfffffff;
188 static uint32_t gnu_hash(const char *s0)
190 const unsigned char *s = (void *)s0;
191 uint_fast32_t h = 5381;
197 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
200 Sym *syms = dso->syms;
201 uint32_t *hashtab = dso->hashtab;
202 char *strings = dso->strings;
203 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
204 if ((!dso->versym || dso->versym[i] >= 0)
205 && (!strcmp(s, strings+syms[i].st_name)))
211 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
213 uint32_t nbuckets = hashtab[0];
214 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
215 uint32_t i = buckets[h1 % nbuckets];
219 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
221 for (h1 |= 1; ; i++) {
222 uint32_t h2 = *hashval++;
223 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
224 && !strcmp(s, dso->strings + dso->syms[i].st_name))
232 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
234 const size_t *bloomwords = (const void *)(hashtab+4);
235 size_t f = bloomwords[fofs & (hashtab[2]-1)];
236 if (!(f & fmask)) return 0;
238 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
239 if (!(f & 1)) return 0;
241 return gnu_lookup(h1, hashtab, dso, s);
244 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
245 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
247 #ifndef ARCH_SYM_REJECT_UND
248 #define ARCH_SYM_REJECT_UND(s) 0
251 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
253 uint32_t h = 0, gh, gho, *ght;
255 struct symdef def = {0};
256 for (; dso; dso=dso->next) {
258 if (!dso->global) continue;
259 if ((ght = dso->ghashtab)) {
262 int maskbits = 8 * sizeof ghm;
264 ghm = 1ul << gh % maskbits;
266 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
268 if (!h) h = sysv_hash(s);
269 sym = sysv_lookup(s, h, dso);
273 if (need_def || (sym->st_info&0xf) == STT_TLS
274 || ARCH_SYM_REJECT_UND(sym))
277 if ((sym->st_info&0xf) != STT_TLS)
279 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
280 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
282 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
285 if (sym->st_info>>4 == STB_GLOBAL) break;
290 __attribute__((__visibility__("hidden")))
291 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
293 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
295 unsigned char *base = dso->base;
296 Sym *syms = dso->syms;
297 char *strings = dso->strings;
308 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
311 /* Only ldso's REL table needs addend saving/reuse. */
312 if (rel == apply_addends_to)
317 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
318 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
319 type = R_TYPE(rel[1]);
320 if (type == REL_NONE) continue;
321 sym_index = R_SYM(rel[1]);
322 reloc_addr = laddr(dso, rel[0]);
324 sym = syms + sym_index;
325 name = strings + sym->st_name;
326 ctx = type==REL_COPY ? head->next : head;
327 def = (sym->st_info&0xf) == STT_SECTION
328 ? (struct symdef){ .dso = dso, .sym = sym }
329 : find_sym(ctx, name, type==REL_PLT);
330 if (!def.sym && (sym->st_shndx != SHN_UNDEF
331 || sym->st_info>>4 != STB_WEAK)) {
332 error("Error relocating %s: %s: symbol not found",
334 if (runtime) longjmp(*rtld_fail, 1);
345 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
347 } else if (reuse_addends) {
348 /* Save original addend in stage 2 where the dso
349 * chain consists of just ldso; otherwise read back
350 * saved addend since the inline one was clobbered. */
352 saved_addends[save_slot] = *reloc_addr;
353 addend = saved_addends[save_slot++];
355 addend = *reloc_addr;
358 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
359 tls_val = def.sym ? def.sym->st_value : 0;
365 addend -= (size_t)reloc_addr;
369 *reloc_addr = sym_val + addend;
372 *reloc_addr = (size_t)base + addend;
375 if (sym) *reloc_addr = sym_val + addend;
376 else *reloc_addr = (size_t)base + addend;
379 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
382 *(uint32_t *)reloc_addr = sym_val + addend
383 - (size_t)reloc_addr;
386 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
387 + (def.sym - def.dso->syms)) : 0;
389 case REL_FUNCDESC_VAL:
390 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
391 else *reloc_addr = sym_val;
392 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
395 *reloc_addr = def.dso->tls_id;
398 *reloc_addr = tls_val + addend - DTP_OFFSET;
402 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
406 *reloc_addr = tls_val - def.dso->tls.offset + addend;
409 *reloc_addr = def.dso->tls.offset - tls_val + addend;
413 if (stride<3) addend = reloc_addr[1];
414 if (runtime && def.dso->tls_id >= static_tls_cnt) {
415 struct td_index *new = malloc(sizeof *new);
418 "Error relocating %s: cannot allocate TLSDESC for %s",
419 dso->name, sym ? name : "(local)" );
420 longjmp(*rtld_fail, 1);
422 new->next = dso->td_index;
424 new->args[0] = def.dso->tls_id;
425 new->args[1] = tls_val + addend;
426 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
427 reloc_addr[1] = (size_t)new;
429 reloc_addr[0] = (size_t)__tlsdesc_static;
431 reloc_addr[1] = tls_val + def.dso->tls.offset
434 reloc_addr[1] = tls_val - def.dso->tls.offset
440 error("Error relocating %s: unsupported relocation type %d",
442 if (runtime) longjmp(*rtld_fail, 1);
448 /* A huge hack: to make up for the wastefulness of shared libraries
449 * needing at least a page of dirty memory even if they have no global
450 * data, we reclaim the gaps at the beginning and end of writable maps
451 * and "donate" them to the heap by setting up minimal malloc
452 * structures and then freeing them. */
454 static void reclaim(struct dso *dso, size_t start, size_t end)
457 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
458 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
459 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
460 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
461 if (start>end || end-start < 4*sizeof(size_t)) return;
462 a = laddr(dso, start);
465 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
470 static void reclaim_gaps(struct dso *dso)
472 Phdr *ph = dso->phdr;
473 size_t phcnt = dso->phnum;
475 if (DL_FDPIC) return; // FIXME
476 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
477 if (ph->p_type!=PT_LOAD) continue;
478 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
479 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
480 reclaim(dso, ph->p_vaddr+ph->p_memsz,
481 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
485 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
487 static int no_map_fixed;
490 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
491 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
495 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
496 if (flags & MAP_ANONYMOUS) {
501 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
502 for (q=p; n; q+=r, off+=r, n-=r) {
504 if (r < 0 && errno != EINTR) return MAP_FAILED;
513 static void unmap_library(struct dso *dso)
517 for (i=0; i<dso->loadmap->nsegs; i++) {
518 if (!dso->loadmap->segs[i].p_memsz)
520 munmap((void *)dso->loadmap->segs[i].addr,
521 dso->loadmap->segs[i].p_memsz);
524 } else if (dso->map && dso->map_len) {
525 munmap(dso->map, dso->map_len);
529 static void *map_library(int fd, struct dso *dso)
531 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
532 void *allocated_buf=0;
534 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
535 size_t this_min, this_max;
541 unsigned char *map=MAP_FAILED, *base;
546 ssize_t l = read(fd, buf, sizeof buf);
549 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
551 phsize = eh->e_phentsize * eh->e_phnum;
552 if (phsize > sizeof buf - sizeof *eh) {
553 allocated_buf = malloc(phsize);
554 if (!allocated_buf) return 0;
555 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
556 if (l < 0) goto error;
557 if (l != phsize) goto noexec;
558 ph = ph0 = allocated_buf;
559 } else if (eh->e_phoff + phsize > l) {
560 l = pread(fd, buf+1, phsize, eh->e_phoff);
561 if (l < 0) goto error;
562 if (l != phsize) goto noexec;
563 ph = ph0 = (void *)(buf + 1);
565 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
567 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
568 if (ph->p_type == PT_DYNAMIC) {
570 } else if (ph->p_type == PT_TLS) {
571 tls_image = ph->p_vaddr;
572 dso->tls.align = ph->p_align;
573 dso->tls.len = ph->p_filesz;
574 dso->tls.size = ph->p_memsz;
575 } else if (ph->p_type == PT_GNU_RELRO) {
576 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
577 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
579 if (ph->p_type != PT_LOAD) continue;
581 if (ph->p_vaddr < addr_min) {
582 addr_min = ph->p_vaddr;
583 off_start = ph->p_offset;
584 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
585 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
586 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
588 if (ph->p_vaddr+ph->p_memsz > addr_max) {
589 addr_max = ph->p_vaddr+ph->p_memsz;
592 if (!dyn) goto noexec;
593 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
594 dso->loadmap = calloc(1, sizeof *dso->loadmap
595 + nsegs * sizeof *dso->loadmap->segs);
596 if (!dso->loadmap) goto error;
597 dso->loadmap->nsegs = nsegs;
598 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
599 if (ph->p_type != PT_LOAD) continue;
600 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
601 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
602 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
603 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
604 prot, (prot&PROT_WRITE) ? MAP_PRIVATE : MAP_SHARED,
605 fd, ph->p_offset & -PAGE_SIZE);
606 if (map == MAP_FAILED) {
610 dso->loadmap->segs[i].addr = (size_t)map +
611 (ph->p_vaddr & PAGE_SIZE-1);
612 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
613 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
615 if (prot & PROT_WRITE) {
616 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
618 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
619 size_t pgend = brk + ph->p_memsz - ph->p_filesz
620 + PAGE_SIZE-1 & -PAGE_SIZE;
621 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
623 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
624 -1, off_start) == MAP_FAILED)
626 memset(map + brk, 0, pgbrk-brk);
629 map = (void *)dso->loadmap->segs[0].addr;
633 addr_max += PAGE_SIZE-1;
634 addr_max &= -PAGE_SIZE;
635 addr_min &= -PAGE_SIZE;
636 off_start &= -PAGE_SIZE;
637 map_len = addr_max - addr_min + off_start;
638 /* The first time, we map too much, possibly even more than
639 * the length of the file. This is okay because we will not
640 * use the invalid part; we just need to reserve the right
641 * amount of virtual address space to map over later. */
642 map = DL_NOMMU_SUPPORT
643 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
644 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
645 : mmap((void *)addr_min, map_len, prot,
646 MAP_PRIVATE, fd, off_start);
647 if (map==MAP_FAILED) goto error;
649 dso->map_len = map_len;
650 /* If the loaded file is not relocatable and the requested address is
651 * not available, then the load operation must fail. */
652 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
656 base = map - addr_min;
659 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
660 if (ph->p_type != PT_LOAD) continue;
661 /* Check if the programs headers are in this load segment, and
662 * if so, record the address for use by dl_iterate_phdr. */
663 if (!dso->phdr && eh->e_phoff >= ph->p_offset
664 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
665 dso->phdr = (void *)(base + ph->p_vaddr
666 + (eh->e_phoff-ph->p_offset));
667 dso->phnum = eh->e_phnum;
668 dso->phentsize = eh->e_phentsize;
670 /* Reuse the existing mapping for the lowest-address LOAD */
671 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT)
673 this_min = ph->p_vaddr & -PAGE_SIZE;
674 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
675 off_start = ph->p_offset & -PAGE_SIZE;
676 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
677 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
678 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
679 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
681 if (ph->p_memsz > ph->p_filesz) {
682 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
683 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
684 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
685 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)
689 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
690 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
691 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
698 dso->dynv = laddr(dso, dyn);
699 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
700 if (!runtime) reclaim_gaps(dso);
706 if (map!=MAP_FAILED) unmap_library(dso);
711 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
716 s += strspn(s, ":\n");
717 l = strcspn(s, ":\n");
718 if (l-1 >= INT_MAX) return -1;
719 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
720 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
728 /* Any negative value but -1 will inhibit
729 * futher path search. */
737 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
740 const char *s, *t, *origin;
742 if (p->rpath || !p->rpath_orig) return 0;
743 if (!strchr(p->rpath_orig, '$')) {
744 p->rpath = p->rpath_orig;
749 while ((t=strchr(s, '$'))) {
750 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
755 if (n > SSIZE_MAX/PATH_MAX) return 0;
757 if (p->kernel_mapped) {
758 /* $ORIGIN searches cannot be performed for the main program
759 * when it is suid/sgid/AT_SECURE. This is because the
760 * pathname is under the control of the caller of execve.
761 * For libraries, however, $ORIGIN can be processed safely
762 * since the library's pathname came from a trusted source
763 * (either system paths or a call to dlopen). */
766 l = readlink("/proc/self/exe", buf, buf_size);
767 if (l == -1) switch (errno) {
782 t = strrchr(origin, '/');
783 l = t ? t-origin : 0;
784 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
785 if (!p->rpath) return -1;
789 while ((t=strchr(s, '$'))) {
792 memcpy(d, origin, l);
794 /* It was determined previously that the '$' is followed
795 * either by "ORIGIN" or "{ORIGIN}". */
796 s = t + 7 + 2*(t[1]=='{');
802 static void decode_dyn(struct dso *p)
805 decode_vec(p->dynv, dyn, DYN_CNT);
806 p->syms = laddr(p, dyn[DT_SYMTAB]);
807 p->strings = laddr(p, dyn[DT_STRTAB]);
808 if (dyn[0]&(1<<DT_HASH))
809 p->hashtab = laddr(p, dyn[DT_HASH]);
810 if (dyn[0]&(1<<DT_RPATH))
811 p->rpath_orig = p->strings + dyn[DT_RPATH];
812 if (dyn[0]&(1<<DT_RUNPATH))
813 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
814 if (dyn[0]&(1<<DT_PLTGOT))
815 p->got = laddr(p, dyn[DT_PLTGOT]);
816 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
817 p->ghashtab = laddr(p, *dyn);
818 if (search_vec(p->dynv, dyn, DT_VERSYM))
819 p->versym = laddr(p, *dyn);
822 static size_t count_syms(struct dso *p)
824 if (p->hashtab) return p->hashtab[1];
827 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
829 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
830 if (buckets[i] > nsym)
834 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
836 while (!(*hashval++ & 1));
841 static void *dl_mmap(size_t n)
844 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
846 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
848 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
850 return p == MAP_FAILED ? 0 : p;
853 static void makefuncdescs(struct dso *p)
855 static int self_done;
856 size_t nsym = count_syms(p);
857 size_t i, size = nsym * sizeof(*p->funcdescs);
860 p->funcdescs = dl_mmap(size);
863 p->funcdescs = malloc(size);
866 if (!runtime) a_crash();
867 error("Error allocating function descriptors for %s", p->name);
868 longjmp(*rtld_fail, 1);
870 for (i=0; i<nsym; i++) {
871 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
872 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
873 p->funcdescs[i].got = p->got;
875 p->funcdescs[i].addr = 0;
876 p->funcdescs[i].got = 0;
881 static struct dso *load_library(const char *name, struct dso *needed_by)
883 char buf[2*NAME_MAX+2];
884 const char *pathname;
886 struct dso *p, temp_dso = {0};
898 /* Catch and block attempts to reload the implementation itself */
899 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
900 static const char *rp, reserved[] =
901 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
902 char *z = strchr(name, '.');
905 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
908 /* Track which names have been resolved
909 * and only report each one once. */
910 static unsigned reported;
911 unsigned mask = 1U<<(rp-reserved);
912 if (!(reported & mask)) {
914 dprintf(1, "\t%s => %s (%p)\n",
923 if (!strcmp(name, ldso.name)) is_self = 1;
928 tail = ldso.next ? ldso.next : &ldso;
932 if (strchr(name, '/')) {
934 fd = open(name, O_RDONLY|O_CLOEXEC);
936 /* Search for the name to see if it's already loaded */
937 for (p=head->next; p; p=p->next) {
938 if (p->shortname && !strcmp(p->shortname, name)) {
943 if (strlen(name) > NAME_MAX) return 0;
945 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
946 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
947 if (fixup_rpath(p, buf, sizeof buf) < 0)
948 fd = -2; /* Inhibit further search. */
950 fd = path_open(name, p->rpath, buf, sizeof buf);
956 if (ldso.name[0]=='/') {
958 for (s=t=z=ldso.name; *s; s++)
959 if (*s=='/') z=t, t=s;
960 prefix_len = z-ldso.name;
961 if (prefix_len < PATH_MAX)
968 char etc_ldso_path[prefix_len + 1
969 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
970 snprintf(etc_ldso_path, sizeof etc_ldso_path,
971 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
972 (int)prefix_len, prefix);
973 FILE *f = fopen(etc_ldso_path, "rbe");
975 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
980 } else if (errno != ENOENT) {
984 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
985 fd = path_open(name, sys_path, buf, sizeof buf);
989 if (fd < 0) return 0;
990 if (fstat(fd, &st) < 0) {
994 for (p=head->next; p; p=p->next) {
995 if (p->dev == st.st_dev && p->ino == st.st_ino) {
996 /* If this library was previously loaded with a
997 * pathname but a search found the same inode,
998 * setup its shortname so it can be found by name. */
999 if (!p->shortname && pathname != name)
1000 p->shortname = strrchr(p->name, '/')+1;
1006 map = noload ? 0 : map_library(fd, &temp_dso);
1010 /* Allocate storage for the new DSO. When there is TLS, this
1011 * storage must include a reservation for all pre-existing
1012 * threads to obtain copies of both the new TLS, and an
1013 * extended DTV capable of storing an additional slot for
1014 * the newly-loaded DSO. */
1015 alloc_size = sizeof *p + strlen(pathname) + 1;
1016 if (runtime && temp_dso.tls.image) {
1017 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1018 + sizeof(void *) * (tls_cnt+3);
1019 n_th = libc.threads_minus_1 + 1;
1020 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1021 else alloc_size += n_th * per_th;
1023 p = calloc(1, alloc_size);
1025 unmap_library(&temp_dso);
1028 memcpy(p, &temp_dso, sizeof temp_dso);
1033 p->needed_by = needed_by;
1035 strcpy(p->name, pathname);
1036 /* Add a shortname only if name arg was not an explicit pathname. */
1037 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1039 p->tls_id = ++tls_cnt;
1040 tls_align = MAXP2(tls_align, p->tls.align);
1042 p->tls.offset = tls_offset + ( (tls_align-1) &
1043 -(tls_offset + (uintptr_t)p->tls.image) );
1044 tls_offset += p->tls.size;
1046 tls_offset += p->tls.size + p->tls.align - 1;
1047 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1049 p->tls.offset = tls_offset;
1051 p->new_dtv = (void *)(-sizeof(size_t) &
1052 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1053 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1054 if (tls_tail) tls_tail->next = &p->tls;
1055 else libc.tls_head = &p->tls;
1063 if (DL_FDPIC) makefuncdescs(p);
1065 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1070 static void load_deps(struct dso *p)
1073 struct dso ***deps = &p->deps, **tmp, *dep;
1074 for (; p; p=p->next) {
1075 for (i=0; p->dynv[i]; i+=2) {
1076 if (p->dynv[i] != DT_NEEDED) continue;
1077 dep = load_library(p->strings + p->dynv[i+1], p);
1079 error("Error loading shared library %s: %m (needed by %s)",
1080 p->strings + p->dynv[i+1], p->name);
1081 if (runtime) longjmp(*rtld_fail, 1);
1085 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1086 if (!tmp) longjmp(*rtld_fail, 1);
1095 static void load_preload(char *s)
1099 for (z=s; *z; s=z) {
1100 for ( ; *s && (isspace(*s) || *s==':'); s++);
1101 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1109 static void make_global(struct dso *p)
1111 for (; p; p=p->next) p->global = 1;
1114 static void do_mips_relocs(struct dso *p, size_t *got)
1116 size_t i, j, rel[2];
1117 unsigned char *base = p->base;
1118 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1122 while (i--) *got++ += (size_t)base;
1124 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1125 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1126 Sym *sym = p->syms + j;
1127 rel[0] = (unsigned char *)got - base;
1128 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1129 rel[1] = sym-p->syms << 8 | R_MIPS_JUMP_SLOT;
1130 do_relocs(p, rel, sizeof rel, 2);
1134 static void reloc_all(struct dso *p)
1136 size_t dyn[DYN_CNT];
1137 for (; p; p=p->next) {
1138 if (p->relocated) continue;
1139 decode_vec(p->dynv, dyn, DYN_CNT);
1140 if (NEED_MIPS_GOT_RELOCS)
1141 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1142 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1143 2+(dyn[DT_PLTREL]==DT_RELA));
1144 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1145 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1147 if (head != &ldso && p->relro_start != p->relro_end &&
1148 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1149 && errno != ENOSYS) {
1150 error("Error relocating %s: RELRO protection failed: %m",
1152 if (runtime) longjmp(*rtld_fail, 1);
1159 static void kernel_mapped_dso(struct dso *p)
1161 size_t min_addr = -1, max_addr = 0, cnt;
1163 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1164 if (ph->p_type == PT_DYNAMIC) {
1165 p->dynv = laddr(p, ph->p_vaddr);
1166 } else if (ph->p_type == PT_GNU_RELRO) {
1167 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1168 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1170 if (ph->p_type != PT_LOAD) continue;
1171 if (ph->p_vaddr < min_addr)
1172 min_addr = ph->p_vaddr;
1173 if (ph->p_vaddr+ph->p_memsz > max_addr)
1174 max_addr = ph->p_vaddr+ph->p_memsz;
1176 min_addr &= -PAGE_SIZE;
1177 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1178 p->map = p->base + min_addr;
1179 p->map_len = max_addr - min_addr;
1180 p->kernel_mapped = 1;
1183 void __libc_exit_fini()
1186 size_t dyn[DYN_CNT];
1187 for (p=fini_head; p; p=p->fini_next) {
1188 if (!p->constructed) continue;
1189 decode_vec(p->dynv, dyn, DYN_CNT);
1190 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1191 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1192 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1193 while (n--) ((void (*)(void))*--fn)();
1195 #ifndef NO_LEGACY_INITFINI
1196 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1197 fpaddr(p, dyn[DT_FINI])();
1202 static void do_init_fini(struct dso *p)
1204 size_t dyn[DYN_CNT];
1205 int need_locking = libc.threads_minus_1;
1206 /* Allow recursive calls that arise when a library calls
1207 * dlopen from one of its constructors, but block any
1208 * other threads until all ctors have finished. */
1209 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1210 for (; p; p=p->prev) {
1211 if (p->constructed) continue;
1213 decode_vec(p->dynv, dyn, DYN_CNT);
1214 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1215 p->fini_next = fini_head;
1218 #ifndef NO_LEGACY_INITFINI
1219 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1220 fpaddr(p, dyn[DT_INIT])();
1222 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1223 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1224 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1225 while (n--) ((void (*)(void))*fn++)();
1227 if (!need_locking && libc.threads_minus_1) {
1229 pthread_mutex_lock(&init_fini_lock);
1232 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1235 void __libc_start_init(void)
1240 static void dl_debug_state(void)
1244 weak_alias(dl_debug_state, _dl_debug_state);
1246 void __init_tls(size_t *auxv)
1250 __attribute__((__visibility__("hidden")))
1251 void *__tls_get_new(size_t *v)
1253 pthread_t self = __pthread_self();
1255 /* Block signals to make accessing new TLS async-signal-safe */
1257 __block_all_sigs(&set);
1258 if (v[0]<=(size_t)self->dtv[0]) {
1259 __restore_sigs(&set);
1260 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1263 /* This is safe without any locks held because, if the caller
1264 * is able to request the Nth entry of the DTV, the DSO list
1265 * must be valid at least that far out and it was synchronized
1266 * at program startup or by an already-completed call to dlopen. */
1268 for (p=head; p->tls_id != v[0]; p=p->next);
1270 /* Get new DTV space from new DSO if needed */
1271 if (v[0] > (size_t)self->dtv[0]) {
1272 void **newdtv = p->new_dtv +
1273 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1274 memcpy(newdtv, self->dtv,
1275 ((size_t)self->dtv[0]+1) * sizeof(void *));
1276 newdtv[0] = (void *)v[0];
1277 self->dtv = self->dtv_copy = newdtv;
1280 /* Get new TLS memory from all new DSOs up to the requested one */
1282 for (p=head; ; p=p->next) {
1283 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1284 mem = p->new_tls + (p->tls.size + p->tls.align)
1285 * a_fetch_add(&p->new_tls_idx,1);
1286 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1288 self->dtv[p->tls_id] = mem;
1289 memcpy(mem, p->tls.image, p->tls.len);
1290 if (p->tls_id == v[0]) break;
1292 __restore_sigs(&set);
1293 return mem + v[1] + DTP_OFFSET;
1296 static void update_tls_size()
1298 libc.tls_cnt = tls_cnt;
1299 libc.tls_align = tls_align;
1300 libc.tls_size = ALIGN(
1301 (1+tls_cnt) * sizeof(void *) +
1303 sizeof(struct pthread) +
1308 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1309 * following stage 2 and stage 3 functions via primitive symbolic lookup
1310 * since it does not have access to their addresses to begin with. */
1312 /* Stage 2 of the dynamic linker is called after relative relocations
1313 * have been processed. It can make function calls to static functions
1314 * and access string literals and static data, but cannot use extern
1315 * symbols. Its job is to perform symbolic relocations on the dynamic
1316 * linker itself, but some of the relocations performed may need to be
1317 * replaced later due to copy relocations in the main program. */
1319 __attribute__((__visibility__("hidden")))
1320 void __dls2(unsigned char *base, size_t *sp)
1323 void *p1 = (void *)sp[-2];
1324 void *p2 = (void *)sp[-1];
1326 size_t *auxv, aux[AUX_CNT];
1327 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1328 decode_vec(auxv, aux, AUX_CNT);
1329 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1330 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1332 app_loadmap = p2 ? p1 : 0;
1333 ldso.loadmap = p2 ? p2 : p1;
1334 ldso.base = laddr(&ldso, 0);
1338 Ehdr *ehdr = (void *)ldso.base;
1339 ldso.name = ldso.shortname = "libc.so";
1341 ldso.phnum = ehdr->e_phnum;
1342 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1343 ldso.phentsize = ehdr->e_phentsize;
1344 kernel_mapped_dso(&ldso);
1347 if (DL_FDPIC) makefuncdescs(&ldso);
1349 /* Prepare storage for to save clobbered REL addends so they
1350 * can be reused in stage 3. There should be very few. If
1351 * something goes wrong and there are a huge number, abort
1352 * instead of risking stack overflow. */
1353 size_t dyn[DYN_CNT];
1354 decode_vec(ldso.dynv, dyn, DYN_CNT);
1355 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1356 size_t rel_size = dyn[DT_RELSZ];
1357 size_t symbolic_rel_cnt = 0;
1358 apply_addends_to = rel;
1359 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1360 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1361 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1362 size_t addends[symbolic_rel_cnt+1];
1363 saved_addends = addends;
1370 /* Call dynamic linker stage-3, __dls3, looking it up
1371 * symbolically as a barrier against moving the address
1372 * load across the above relocation processing. */
1373 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1374 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1375 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1378 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1379 * fully functional. Its job is to load (if not already loaded) and
1380 * process dependencies and relocations for the main application and
1381 * transfer control to its entry point. */
1383 _Noreturn void __dls3(size_t *sp)
1385 static struct dso app, vdso;
1386 size_t aux[AUX_CNT], *auxv;
1388 char *env_preload=0;
1391 char **argv = (void *)(sp+1);
1392 char **argv_orig = argv;
1393 char **envp = argv+argc+1;
1395 /* Find aux vector just past environ[] and use it to initialize
1396 * global data that may be needed before we can make syscalls. */
1398 for (i=argc+1; argv[i]; i++);
1399 libc.auxv = auxv = (void *)(argv+i+1);
1400 decode_vec(auxv, aux, AUX_CNT);
1401 __hwcap = aux[AT_HWCAP];
1402 libc.page_size = aux[AT_PAGESZ];
1403 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1404 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1406 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1407 * use during dynamic linking. If possible it will also serve as the
1408 * thread pointer at runtime. */
1409 libc.tls_size = sizeof builtin_tls;
1410 libc.tls_align = tls_align;
1411 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1415 /* Only trust user/env if kernel says we're not suid/sgid */
1417 env_path = getenv("LD_LIBRARY_PATH");
1418 env_preload = getenv("LD_PRELOAD");
1421 /* If the main program was already loaded by the kernel,
1422 * AT_PHDR will point to some location other than the dynamic
1423 * linker's program headers. */
1424 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1425 size_t interp_off = 0;
1426 size_t tls_image = 0;
1427 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1428 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1429 app.phnum = aux[AT_PHNUM];
1430 app.phentsize = aux[AT_PHENT];
1431 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1432 if (phdr->p_type == PT_PHDR)
1433 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1434 else if (phdr->p_type == PT_INTERP)
1435 interp_off = (size_t)phdr->p_vaddr;
1436 else if (phdr->p_type == PT_TLS) {
1437 tls_image = phdr->p_vaddr;
1438 app.tls.len = phdr->p_filesz;
1439 app.tls.size = phdr->p_memsz;
1440 app.tls.align = phdr->p_align;
1443 if (DL_FDPIC) app.loadmap = app_loadmap;
1444 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1445 if (interp_off) ldso.name = laddr(&app, interp_off);
1446 if ((aux[0] & (1UL<<AT_EXECFN))
1447 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1448 app.name = (char *)aux[AT_EXECFN];
1451 kernel_mapped_dso(&app);
1454 char *ldname = argv[0];
1455 size_t l = strlen(ldname);
1456 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1458 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1459 char *opt = argv[0]+2;
1460 *argv++ = (void *)-1;
1463 } else if (!memcmp(opt, "list", 5)) {
1465 } else if (!memcmp(opt, "library-path", 12)) {
1466 if (opt[12]=='=') env_path = opt+13;
1467 else if (opt[12]) *argv = 0;
1468 else if (*argv) env_path = *argv++;
1469 } else if (!memcmp(opt, "preload", 7)) {
1470 if (opt[7]=='=') env_preload = opt+8;
1471 else if (opt[7]) *argv = 0;
1472 else if (*argv) env_preload = *argv++;
1477 argv[-1] = (void *)(argc - (argv-argv_orig));
1479 dprintf(2, "musl libc\n"
1481 "Dynamic Program Loader\n"
1482 "Usage: %s [options] [--] pathname%s\n",
1483 __libc_get_version(), ldname,
1484 ldd_mode ? "" : " [args]");
1487 fd = open(argv[0], O_RDONLY);
1489 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1493 Ehdr *ehdr = (void *)map_library(fd, &app);
1495 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1502 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1503 /* Find the name that would have been used for the dynamic
1504 * linker had ldd not taken its place. */
1506 for (i=0; i<app.phnum; i++) {
1507 if (app.phdr[i].p_type == PT_INTERP)
1508 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1510 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1514 libc.tls_head = &app.tls;
1515 app.tls_id = tls_cnt = 1;
1518 tls_offset = app.tls.size
1519 + ( -((uintptr_t)app.tls.image + app.tls.size)
1520 & (app.tls.align-1) );
1522 tls_offset = app.tls.offset = app.tls.size
1523 + ( -((uintptr_t)app.tls.image + app.tls.size)
1524 & (app.tls.align-1) );
1526 tls_align = MAXP2(tls_align, app.tls.align);
1531 makefuncdescs(&app);
1533 app.loadmap = (void *)&app_dummy_loadmap;
1534 app.loadmap->nsegs = 1;
1535 app.loadmap->segs[0].addr = (size_t)app.map;
1536 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1538 app.loadmap->segs[0].p_memsz = app.map_len;
1540 argv[-3] = (void *)app.loadmap;
1543 /* Attach to vdso, if provided by the kernel */
1544 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1545 Ehdr *ehdr = (void *)vdso_base;
1546 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1547 vdso.phnum = ehdr->e_phnum;
1548 vdso.phentsize = ehdr->e_phentsize;
1549 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1550 if (phdr->p_type == PT_DYNAMIC)
1551 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1552 if (phdr->p_type == PT_LOAD)
1553 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1556 vdso.shortname = "linux-gate.so.1";
1564 /* Initial dso chain consists only of the app. */
1567 /* Donate unused parts of app and library mapping to malloc */
1569 reclaim_gaps(&ldso);
1571 /* Load preload/needed libraries, add their symbols to the global
1572 * namespace, and perform all remaining relocations. */
1573 if (env_preload) load_preload(env_preload);
1577 #ifndef DYNAMIC_IS_RO
1578 for (i=0; app.dynv[i]; i+=2)
1579 if (app.dynv[i]==DT_DEBUG)
1580 app.dynv[i+1] = (size_t)&debug;
1583 /* The main program must be relocated LAST since it may contin
1584 * copy relocations which depend on libraries' relocations. */
1585 reloc_all(app.next);
1589 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1590 void *initial_tls = calloc(libc.tls_size, 1);
1592 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1593 argv[0], libc.tls_size);
1596 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1600 size_t tmp_tls_size = libc.tls_size;
1601 pthread_t self = __pthread_self();
1602 /* Temporarily set the tls size to the full size of
1603 * builtin_tls so that __copy_tls will use the same layout
1604 * as it did for before. Then check, just to be safe. */
1605 libc.tls_size = sizeof builtin_tls;
1606 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1607 libc.tls_size = tmp_tls_size;
1609 static_tls_cnt = tls_cnt;
1611 if (ldso_fail) _exit(127);
1612 if (ldd_mode) _exit(0);
1614 /* Switch to runtime mode: any further failures in the dynamic
1615 * linker are a reportable failure rather than a fatal startup
1620 debug.bp = dl_debug_state;
1622 debug.base = ldso.base;
1628 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1632 void *dlopen(const char *file, int mode)
1634 struct dso *volatile p, *orig_tail, *next;
1635 struct tls_module *orig_tls_tail;
1636 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1641 if (!file) return head;
1643 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1644 pthread_rwlock_wrlock(&lock);
1648 orig_tls_tail = tls_tail;
1649 orig_tls_cnt = tls_cnt;
1650 orig_tls_offset = tls_offset;
1651 orig_tls_align = tls_align;
1653 noload = mode & RTLD_NOLOAD;
1656 if (setjmp(*rtld_fail)) {
1657 /* Clean up anything new that was (partially) loaded */
1658 if (p && p->deps) for (i=0; p->deps[i]; i++)
1659 if (p->deps[i]->global < 0)
1660 p->deps[i]->global = 0;
1661 for (p=orig_tail->next; p; p=next) {
1663 while (p->td_index) {
1664 void *tmp = p->td_index->next;
1669 if (p->rpath != p->rpath_orig)
1675 if (!orig_tls_tail) libc.tls_head = 0;
1676 tls_tail = orig_tls_tail;
1677 tls_cnt = orig_tls_cnt;
1678 tls_offset = orig_tls_offset;
1679 tls_align = orig_tls_align;
1684 } else p = load_library(file, head);
1688 "Library %s is not already loaded" :
1689 "Error loading shared library %s: %m",
1694 /* First load handling */
1697 if (p->deps) for (i=0; p->deps[i]; i++)
1698 if (!p->deps[i]->global)
1699 p->deps[i]->global = -1;
1700 if (!p->global) p->global = -1;
1702 if (p->deps) for (i=0; p->deps[i]; i++)
1703 if (p->deps[i]->global < 0)
1704 p->deps[i]->global = 0;
1705 if (p->global < 0) p->global = 0;
1708 if (mode & RTLD_GLOBAL) {
1709 if (p->deps) for (i=0; p->deps[i]; i++)
1710 p->deps[i]->global = 1;
1720 pthread_rwlock_unlock(&lock);
1721 if (p) do_init_fini(orig_tail);
1722 pthread_setcancelstate(cs, 0);
1726 static int invalid_dso_handle(void *h)
1729 for (p=head; p; p=p->next) if (h==p) return 0;
1730 error("Invalid library handle %p", (void *)h);
1734 static void *addr2dso(size_t a)
1738 if (DL_FDPIC) for (p=head; p; p=p->next) {
1740 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1743 for (p=head; p; p=p->next) {
1744 if (DL_FDPIC && p->loadmap) {
1745 for (i=0; i<p->loadmap->nsegs; i++) {
1746 if (a-p->loadmap->segs[i].p_vaddr
1747 < p->loadmap->segs[i].p_memsz)
1751 if (a-(size_t)p->map < p->map_len)
1758 void *__tls_get_addr(size_t *);
1760 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1763 uint32_t h = 0, gh = 0, *ght;
1765 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1766 if (p == RTLD_DEFAULT) {
1768 } else if (p == RTLD_NEXT) {
1769 p = addr2dso((size_t)ra);
1773 struct symdef def = find_sym(p, s, 0);
1774 if (!def.sym) goto failed;
1775 if ((def.sym->st_info&0xf) == STT_TLS)
1776 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1777 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1778 return def.dso->funcdescs + (def.sym - def.dso->syms);
1779 return laddr(def.dso, def.sym->st_value);
1781 if (invalid_dso_handle(p))
1783 if ((ght = p->ghashtab)) {
1785 sym = gnu_lookup(gh, ght, p, s);
1788 sym = sysv_lookup(s, h, p);
1790 if (sym && (sym->st_info&0xf) == STT_TLS)
1791 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1792 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1793 return p->funcdescs + (sym - p->syms);
1794 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1795 return laddr(p, sym->st_value);
1796 if (p->deps) for (i=0; p->deps[i]; i++) {
1797 if ((ght = p->deps[i]->ghashtab)) {
1798 if (!gh) gh = gnu_hash(s);
1799 sym = gnu_lookup(gh, ght, p->deps[i], s);
1801 if (!h) h = sysv_hash(s);
1802 sym = sysv_lookup(s, h, p->deps[i]);
1804 if (sym && (sym->st_info&0xf) == STT_TLS)
1805 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1806 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1807 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1808 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1809 return laddr(p->deps[i], sym->st_value);
1812 error("Symbol not found: %s", s);
1816 int __dladdr(const void *addr, Dl_info *info)
1824 pthread_rwlock_rdlock(&lock);
1825 p = addr2dso((size_t)addr);
1826 pthread_rwlock_unlock(&lock);
1831 strings = p->strings;
1832 nsym = count_syms(p);
1835 size_t idx = ((size_t)addr-(size_t)p->funcdescs)
1836 / sizeof(*p->funcdescs);
1837 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1838 best = p->funcdescs + idx;
1839 bestsym = sym + idx;
1843 if (!best) for (; nsym; nsym--, sym++) {
1845 && (1<<(sym->st_info&0xf) & OK_TYPES)
1846 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1847 void *symaddr = laddr(p, sym->st_value);
1848 if (symaddr > addr || symaddr < best)
1852 if (addr == symaddr)
1857 if (!best) return 0;
1859 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
1860 best = p->funcdescs + (bestsym - p->syms);
1862 info->dli_fname = p->name;
1863 info->dli_fbase = p->base;
1864 info->dli_sname = strings + bestsym->st_name;
1865 info->dli_saddr = best;
1870 __attribute__((__visibility__("hidden")))
1871 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1874 pthread_rwlock_rdlock(&lock);
1875 res = do_dlsym(p, s, ra);
1876 pthread_rwlock_unlock(&lock);
1880 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1882 struct dso *current;
1883 struct dl_phdr_info info;
1885 for(current = head; current;) {
1886 info.dlpi_addr = (uintptr_t)current->base;
1887 info.dlpi_name = current->name;
1888 info.dlpi_phdr = current->phdr;
1889 info.dlpi_phnum = current->phnum;
1890 info.dlpi_adds = gencnt;
1892 info.dlpi_tls_modid = current->tls_id;
1893 info.dlpi_tls_data = current->tls.image;
1895 ret = (callback)(&info, sizeof (info), data);
1897 if (ret != 0) break;
1899 pthread_rwlock_rdlock(&lock);
1900 current = current->next;
1901 pthread_rwlock_unlock(&lock);
1906 static int invalid_dso_handle(void *h)
1908 error("Invalid library handle %p", (void *)h);
1911 void *dlopen(const char *file, int mode)
1913 error("Dynamic loading not supported");
1916 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1918 error("Symbol not found: %s", s);
1921 int __dladdr (const void *addr, Dl_info *info)
1927 int __dlinfo(void *dso, int req, void *res)
1929 if (invalid_dso_handle(dso)) return -1;
1930 if (req != RTLD_DI_LINKMAP) {
1931 error("Unsupported request %d", req);
1934 *(struct link_map **)res = dso;
1940 pthread_t self = __pthread_self();
1941 if (!self->dlerror_flag) return 0;
1942 self->dlerror_flag = 0;
1943 char *s = self->dlerror_buf;
1944 if (s == (void *)-1)
1945 return "Dynamic linker failed to allocate memory for error message";
1950 int dlclose(void *p)
1952 return invalid_dso_handle(p);
1955 void __dl_thread_cleanup(void)
1957 pthread_t self = __pthread_self();
1958 if (self->dlerror_buf != (void *)-1)
1959 free(self->dlerror_buf);
1962 static void error(const char *fmt, ...)
1968 vdprintf(2, fmt, ap);
1975 pthread_t self = __pthread_self();
1976 if (self->dlerror_buf != (void *)-1)
1977 free(self->dlerror_buf);
1978 size_t len = vsnprintf(0, 0, fmt, ap);
1980 char *buf = malloc(len+1);
1983 vsnprintf(buf, len+1, fmt, ap);
1988 self->dlerror_buf = buf;
1989 self->dlerror_flag = 1;