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;
69 struct dso **deps, *needed_by;
70 char *rpath_orig, *rpath;
71 struct tls_module tls;
73 size_t relro_start, relro_end;
75 unsigned char *new_tls;
76 volatile int new_dtv_idx, new_tls_idx;
77 struct td_index *td_index;
78 struct dso *fini_next;
83 struct fdpic_loadmap *loadmap;
98 int __init_tp(void *);
99 void __init_libc(char **, char *);
100 void *__copy_tls(unsigned char *);
102 __attribute__((__visibility__("hidden")))
103 const char *__libc_get_version(void);
105 static struct builtin_tls {
110 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
112 #define ADDEND_LIMIT 4096
113 static size_t *saved_addends, *apply_addends_to;
115 static struct dso ldso;
116 static struct dso *head, *tail, *fini_head;
117 static char *env_path, *sys_path;
118 static unsigned long long gencnt;
121 static int ldso_fail;
123 static jmp_buf *rtld_fail;
124 static pthread_rwlock_t lock;
125 static struct debug debug;
126 static struct tls_module *tls_tail;
127 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
128 static size_t static_tls_cnt;
129 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
130 static struct fdpic_loadmap *app_loadmap;
131 static struct fdpic_dummy_loadmap app_dummy_loadmap;
133 struct debug *_dl_debug_addr = &debug;
135 __attribute__((__visibility__("hidden")))
136 void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
138 __attribute__((__visibility__("hidden")))
139 extern void (*const __init_array_end)(void), (*const __fini_array_end)(void);
141 weak_alias(__init_array_start, __init_array_end);
142 weak_alias(__fini_array_start, __fini_array_end);
144 static int dl_strcmp(const char *l, const char *r)
146 for (; *l==*r && *l; l++, r++);
147 return *(unsigned char *)l - *(unsigned char *)r;
149 #define strcmp(l,r) dl_strcmp(l,r)
151 /* Compute load address for a virtual address in a given dso. */
153 static void *laddr(const struct dso *p, size_t v)
156 if (!p->loadmap) return p->base + v;
157 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
158 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
160 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
161 laddr(p, v), (p)->got })
163 #define laddr(p, v) (void *)((p)->base + (v))
164 #define fpaddr(p, v) ((void (*)())laddr(p, v))
167 static void decode_vec(size_t *v, size_t *a, size_t cnt)
170 for (i=0; i<cnt; i++) a[i] = 0;
171 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
177 static int search_vec(size_t *v, size_t *r, size_t key)
179 for (; v[0]!=key; v+=2)
185 static uint32_t sysv_hash(const char *s0)
187 const unsigned char *s = (void *)s0;
193 return h & 0xfffffff;
196 static uint32_t gnu_hash(const char *s0)
198 const unsigned char *s = (void *)s0;
199 uint_fast32_t h = 5381;
205 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
208 Sym *syms = dso->syms;
209 uint32_t *hashtab = dso->hashtab;
210 char *strings = dso->strings;
211 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
212 if ((!dso->versym || dso->versym[i] >= 0)
213 && (!strcmp(s, strings+syms[i].st_name)))
219 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
221 uint32_t nbuckets = hashtab[0];
222 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
223 uint32_t i = buckets[h1 % nbuckets];
227 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
229 for (h1 |= 1; ; i++) {
230 uint32_t h2 = *hashval++;
231 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
232 && !strcmp(s, dso->strings + dso->syms[i].st_name))
240 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
242 const size_t *bloomwords = (const void *)(hashtab+4);
243 size_t f = bloomwords[fofs & (hashtab[2]-1)];
244 if (!(f & fmask)) return 0;
246 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
247 if (!(f & 1)) return 0;
249 return gnu_lookup(h1, hashtab, dso, s);
252 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
253 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
255 #ifndef ARCH_SYM_REJECT_UND
256 #define ARCH_SYM_REJECT_UND(s) 0
259 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
261 uint32_t h = 0, gh, gho, *ght;
263 struct symdef def = {0};
264 for (; dso; dso=dso->next) {
266 if (!dso->global) continue;
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;
290 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
293 if (sym->st_info>>4 == STB_GLOBAL) break;
298 __attribute__((__visibility__("hidden")))
299 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
301 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
303 unsigned char *base = dso->base;
304 Sym *syms = dso->syms;
305 char *strings = dso->strings;
316 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
319 /* Only ldso's REL table needs addend saving/reuse. */
320 if (rel == apply_addends_to)
325 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
326 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
327 type = R_TYPE(rel[1]);
328 if (type == REL_NONE) continue;
329 sym_index = R_SYM(rel[1]);
330 reloc_addr = laddr(dso, rel[0]);
332 sym = syms + sym_index;
333 name = strings + sym->st_name;
334 ctx = type==REL_COPY ? head->next : head;
335 def = (sym->st_info&0xf) == STT_SECTION
336 ? (struct symdef){ .dso = dso, .sym = sym }
337 : find_sym(ctx, name, type==REL_PLT);
338 if (!def.sym && (sym->st_shndx != SHN_UNDEF
339 || sym->st_info>>4 != STB_WEAK)) {
340 error("Error relocating %s: %s: symbol not found",
342 if (runtime) longjmp(*rtld_fail, 1);
353 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
355 } else if (reuse_addends) {
356 /* Save original addend in stage 2 where the dso
357 * chain consists of just ldso; otherwise read back
358 * saved addend since the inline one was clobbered. */
360 saved_addends[save_slot] = *reloc_addr;
361 addend = saved_addends[save_slot++];
363 addend = *reloc_addr;
366 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
367 tls_val = def.sym ? def.sym->st_value : 0;
373 addend -= (size_t)reloc_addr;
377 *reloc_addr = sym_val + addend;
380 *reloc_addr = (size_t)base + addend;
383 if (sym) *reloc_addr = sym_val + addend;
384 else *reloc_addr = (size_t)base + addend;
387 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
390 *(uint32_t *)reloc_addr = sym_val + addend
391 - (size_t)reloc_addr;
394 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
395 + (def.sym - def.dso->syms)) : 0;
397 case REL_FUNCDESC_VAL:
398 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
399 else *reloc_addr = sym_val;
400 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
403 *reloc_addr = def.dso->tls_id;
406 *reloc_addr = tls_val + addend - DTP_OFFSET;
410 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
414 *reloc_addr = tls_val - def.dso->tls.offset + addend;
417 *reloc_addr = def.dso->tls.offset - tls_val + addend;
421 if (stride<3) addend = reloc_addr[1];
422 if (runtime && def.dso->tls_id >= static_tls_cnt) {
423 struct td_index *new = malloc(sizeof *new);
426 "Error relocating %s: cannot allocate TLSDESC for %s",
427 dso->name, sym ? name : "(local)" );
428 longjmp(*rtld_fail, 1);
430 new->next = dso->td_index;
432 new->args[0] = def.dso->tls_id;
433 new->args[1] = tls_val + addend;
434 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
435 reloc_addr[1] = (size_t)new;
437 reloc_addr[0] = (size_t)__tlsdesc_static;
439 reloc_addr[1] = tls_val + def.dso->tls.offset
442 reloc_addr[1] = tls_val - def.dso->tls.offset
448 error("Error relocating %s: unsupported relocation type %d",
450 if (runtime) longjmp(*rtld_fail, 1);
456 /* A huge hack: to make up for the wastefulness of shared libraries
457 * needing at least a page of dirty memory even if they have no global
458 * data, we reclaim the gaps at the beginning and end of writable maps
459 * and "donate" them to the heap by setting up minimal malloc
460 * structures and then freeing them. */
462 static void reclaim(struct dso *dso, size_t start, size_t end)
465 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
466 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
467 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
468 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
469 if (start>end || end-start < 4*sizeof(size_t)) return;
470 a = laddr(dso, start);
473 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
478 static void reclaim_gaps(struct dso *dso)
480 Phdr *ph = dso->phdr;
481 size_t phcnt = dso->phnum;
483 if (DL_FDPIC) return; // FIXME
484 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
485 if (ph->p_type!=PT_LOAD) continue;
486 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
487 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
488 reclaim(dso, ph->p_vaddr+ph->p_memsz,
489 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
493 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
495 static int no_map_fixed;
498 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
499 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
503 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
504 if (flags & MAP_ANONYMOUS) {
509 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
510 for (q=p; n; q+=r, off+=r, n-=r) {
512 if (r < 0 && errno != EINTR) return MAP_FAILED;
521 static void unmap_library(struct dso *dso)
525 for (i=0; i<dso->loadmap->nsegs; i++) {
526 if (!dso->loadmap->segs[i].p_memsz)
528 munmap((void *)dso->loadmap->segs[i].addr,
529 dso->loadmap->segs[i].p_memsz);
532 } else if (dso->map && dso->map_len) {
533 munmap(dso->map, dso->map_len);
537 static void *map_library(int fd, struct dso *dso)
539 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
540 void *allocated_buf=0;
542 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
543 size_t this_min, this_max;
549 unsigned char *map=MAP_FAILED, *base;
554 ssize_t l = read(fd, buf, sizeof buf);
557 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
559 phsize = eh->e_phentsize * eh->e_phnum;
560 if (phsize > sizeof buf - sizeof *eh) {
561 allocated_buf = malloc(phsize);
562 if (!allocated_buf) return 0;
563 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
564 if (l < 0) goto error;
565 if (l != phsize) goto noexec;
566 ph = ph0 = allocated_buf;
567 } else if (eh->e_phoff + phsize > l) {
568 l = pread(fd, buf+1, phsize, eh->e_phoff);
569 if (l < 0) goto error;
570 if (l != phsize) goto noexec;
571 ph = ph0 = (void *)(buf + 1);
573 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
575 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
576 if (ph->p_type == PT_DYNAMIC) {
578 } else if (ph->p_type == PT_TLS) {
579 tls_image = ph->p_vaddr;
580 dso->tls.align = ph->p_align;
581 dso->tls.len = ph->p_filesz;
582 dso->tls.size = ph->p_memsz;
583 } else if (ph->p_type == PT_GNU_RELRO) {
584 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
585 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
587 if (ph->p_type != PT_LOAD) continue;
589 if (ph->p_vaddr < addr_min) {
590 addr_min = ph->p_vaddr;
591 off_start = ph->p_offset;
592 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
593 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
594 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
596 if (ph->p_vaddr+ph->p_memsz > addr_max) {
597 addr_max = ph->p_vaddr+ph->p_memsz;
600 if (!dyn) goto noexec;
601 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
602 dso->loadmap = calloc(1, sizeof *dso->loadmap
603 + nsegs * sizeof *dso->loadmap->segs);
604 if (!dso->loadmap) goto error;
605 dso->loadmap->nsegs = nsegs;
606 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
607 if (ph->p_type != PT_LOAD) continue;
608 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
609 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
610 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
611 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
613 fd, ph->p_offset & -PAGE_SIZE);
614 if (map == MAP_FAILED) {
618 dso->loadmap->segs[i].addr = (size_t)map +
619 (ph->p_vaddr & PAGE_SIZE-1);
620 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
621 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
623 if (prot & PROT_WRITE) {
624 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
626 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
627 size_t pgend = brk + ph->p_memsz - ph->p_filesz
628 + PAGE_SIZE-1 & -PAGE_SIZE;
629 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
631 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
632 -1, off_start) == MAP_FAILED)
634 memset(map + brk, 0, pgbrk-brk);
637 map = (void *)dso->loadmap->segs[0].addr;
641 addr_max += PAGE_SIZE-1;
642 addr_max &= -PAGE_SIZE;
643 addr_min &= -PAGE_SIZE;
644 off_start &= -PAGE_SIZE;
645 map_len = addr_max - addr_min + off_start;
646 /* The first time, we map too much, possibly even more than
647 * the length of the file. This is okay because we will not
648 * use the invalid part; we just need to reserve the right
649 * amount of virtual address space to map over later. */
650 map = DL_NOMMU_SUPPORT
651 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
652 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
653 : mmap((void *)addr_min, map_len, prot,
654 MAP_PRIVATE, fd, off_start);
655 if (map==MAP_FAILED) goto error;
657 dso->map_len = map_len;
658 /* If the loaded file is not relocatable and the requested address is
659 * not available, then the load operation must fail. */
660 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
664 base = map - addr_min;
667 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
668 if (ph->p_type != PT_LOAD) continue;
669 /* Check if the programs headers are in this load segment, and
670 * if so, record the address for use by dl_iterate_phdr. */
671 if (!dso->phdr && eh->e_phoff >= ph->p_offset
672 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
673 dso->phdr = (void *)(base + ph->p_vaddr
674 + (eh->e_phoff-ph->p_offset));
675 dso->phnum = eh->e_phnum;
676 dso->phentsize = eh->e_phentsize;
678 /* Reuse the existing mapping for the lowest-address LOAD */
679 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT)
681 this_min = ph->p_vaddr & -PAGE_SIZE;
682 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
683 off_start = ph->p_offset & -PAGE_SIZE;
684 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
685 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
686 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
687 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
689 if (ph->p_memsz > ph->p_filesz) {
690 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
691 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
692 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
693 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)
697 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
698 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
699 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
706 dso->dynv = laddr(dso, dyn);
707 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
708 if (!runtime) reclaim_gaps(dso);
714 if (map!=MAP_FAILED) unmap_library(dso);
719 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
724 s += strspn(s, ":\n");
725 l = strcspn(s, ":\n");
726 if (l-1 >= INT_MAX) return -1;
727 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
728 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
736 /* Any negative value but -1 will inhibit
737 * futher path search. */
745 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
748 const char *s, *t, *origin;
750 if (p->rpath || !p->rpath_orig) return 0;
751 if (!strchr(p->rpath_orig, '$')) {
752 p->rpath = p->rpath_orig;
757 while ((t=strchr(s, '$'))) {
758 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
763 if (n > SSIZE_MAX/PATH_MAX) return 0;
765 if (p->kernel_mapped) {
766 /* $ORIGIN searches cannot be performed for the main program
767 * when it is suid/sgid/AT_SECURE. This is because the
768 * pathname is under the control of the caller of execve.
769 * For libraries, however, $ORIGIN can be processed safely
770 * since the library's pathname came from a trusted source
771 * (either system paths or a call to dlopen). */
774 l = readlink("/proc/self/exe", buf, buf_size);
775 if (l == -1) switch (errno) {
790 t = strrchr(origin, '/');
791 l = t ? t-origin : 0;
792 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
793 if (!p->rpath) return -1;
797 while ((t=strchr(s, '$'))) {
800 memcpy(d, origin, l);
802 /* It was determined previously that the '$' is followed
803 * either by "ORIGIN" or "{ORIGIN}". */
804 s = t + 7 + 2*(t[1]=='{');
810 static void decode_dyn(struct dso *p)
813 decode_vec(p->dynv, dyn, DYN_CNT);
814 p->syms = laddr(p, dyn[DT_SYMTAB]);
815 p->strings = laddr(p, dyn[DT_STRTAB]);
816 if (dyn[0]&(1<<DT_HASH))
817 p->hashtab = laddr(p, dyn[DT_HASH]);
818 if (dyn[0]&(1<<DT_RPATH))
819 p->rpath_orig = p->strings + dyn[DT_RPATH];
820 if (dyn[0]&(1<<DT_RUNPATH))
821 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
822 if (dyn[0]&(1<<DT_PLTGOT))
823 p->got = laddr(p, dyn[DT_PLTGOT]);
824 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
825 p->ghashtab = laddr(p, *dyn);
826 if (search_vec(p->dynv, dyn, DT_VERSYM))
827 p->versym = laddr(p, *dyn);
830 static size_t count_syms(struct dso *p)
832 if (p->hashtab) return p->hashtab[1];
835 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
837 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
838 if (buckets[i] > nsym)
842 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
844 while (!(*hashval++ & 1));
849 static void *dl_mmap(size_t n)
852 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
854 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
856 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
858 return p == MAP_FAILED ? 0 : p;
861 static void makefuncdescs(struct dso *p)
863 static int self_done;
864 size_t nsym = count_syms(p);
865 size_t i, size = nsym * sizeof(*p->funcdescs);
868 p->funcdescs = dl_mmap(size);
871 p->funcdescs = malloc(size);
874 if (!runtime) a_crash();
875 error("Error allocating function descriptors for %s", p->name);
876 longjmp(*rtld_fail, 1);
878 for (i=0; i<nsym; i++) {
879 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
880 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
881 p->funcdescs[i].got = p->got;
883 p->funcdescs[i].addr = 0;
884 p->funcdescs[i].got = 0;
889 static struct dso *load_library(const char *name, struct dso *needed_by)
891 char buf[2*NAME_MAX+2];
892 const char *pathname;
894 struct dso *p, temp_dso = {0};
906 /* Catch and block attempts to reload the implementation itself */
907 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
908 static const char *rp, reserved[] =
909 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
910 char *z = strchr(name, '.');
913 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
916 /* Track which names have been resolved
917 * and only report each one once. */
918 static unsigned reported;
919 unsigned mask = 1U<<(rp-reserved);
920 if (!(reported & mask)) {
922 dprintf(1, "\t%s => %s (%p)\n",
931 if (!strcmp(name, ldso.name)) is_self = 1;
936 tail = ldso.next ? ldso.next : &ldso;
940 if (strchr(name, '/')) {
942 fd = open(name, O_RDONLY|O_CLOEXEC);
944 /* Search for the name to see if it's already loaded */
945 for (p=head->next; p; p=p->next) {
946 if (p->shortname && !strcmp(p->shortname, name)) {
951 if (strlen(name) > NAME_MAX) return 0;
953 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
954 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
955 if (fixup_rpath(p, buf, sizeof buf) < 0)
956 fd = -2; /* Inhibit further search. */
958 fd = path_open(name, p->rpath, buf, sizeof buf);
964 if (ldso.name[0]=='/') {
966 for (s=t=z=ldso.name; *s; s++)
967 if (*s=='/') z=t, t=s;
968 prefix_len = z-ldso.name;
969 if (prefix_len < PATH_MAX)
976 char etc_ldso_path[prefix_len + 1
977 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
978 snprintf(etc_ldso_path, sizeof etc_ldso_path,
979 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
980 (int)prefix_len, prefix);
981 FILE *f = fopen(etc_ldso_path, "rbe");
983 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
988 } else if (errno != ENOENT) {
992 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
993 fd = path_open(name, sys_path, buf, sizeof buf);
997 if (fd < 0) return 0;
998 if (fstat(fd, &st) < 0) {
1002 for (p=head->next; p; p=p->next) {
1003 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1004 /* If this library was previously loaded with a
1005 * pathname but a search found the same inode,
1006 * setup its shortname so it can be found by name. */
1007 if (!p->shortname && pathname != name)
1008 p->shortname = strrchr(p->name, '/')+1;
1014 map = noload ? 0 : map_library(fd, &temp_dso);
1018 /* Allocate storage for the new DSO. When there is TLS, this
1019 * storage must include a reservation for all pre-existing
1020 * threads to obtain copies of both the new TLS, and an
1021 * extended DTV capable of storing an additional slot for
1022 * the newly-loaded DSO. */
1023 alloc_size = sizeof *p + strlen(pathname) + 1;
1024 if (runtime && temp_dso.tls.image) {
1025 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1026 + sizeof(void *) * (tls_cnt+3);
1027 n_th = libc.threads_minus_1 + 1;
1028 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1029 else alloc_size += n_th * per_th;
1031 p = calloc(1, alloc_size);
1033 unmap_library(&temp_dso);
1036 memcpy(p, &temp_dso, sizeof temp_dso);
1041 p->needed_by = needed_by;
1043 strcpy(p->name, pathname);
1044 /* Add a shortname only if name arg was not an explicit pathname. */
1045 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1047 p->tls_id = ++tls_cnt;
1048 tls_align = MAXP2(tls_align, p->tls.align);
1050 p->tls.offset = tls_offset + ( (tls_align-1) &
1051 -(tls_offset + (uintptr_t)p->tls.image) );
1052 tls_offset += p->tls.size;
1054 tls_offset += p->tls.size + p->tls.align - 1;
1055 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1057 p->tls.offset = tls_offset;
1059 p->new_dtv = (void *)(-sizeof(size_t) &
1060 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1061 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1062 if (tls_tail) tls_tail->next = &p->tls;
1063 else libc.tls_head = &p->tls;
1071 if (DL_FDPIC) makefuncdescs(p);
1073 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1078 static void load_deps(struct dso *p)
1081 struct dso ***deps = &p->deps, **tmp, *dep;
1082 for (; p; p=p->next) {
1083 for (i=0; p->dynv[i]; i+=2) {
1084 if (p->dynv[i] != DT_NEEDED) continue;
1085 dep = load_library(p->strings + p->dynv[i+1], p);
1087 error("Error loading shared library %s: %m (needed by %s)",
1088 p->strings + p->dynv[i+1], p->name);
1089 if (runtime) longjmp(*rtld_fail, 1);
1093 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1094 if (!tmp) longjmp(*rtld_fail, 1);
1103 static void load_preload(char *s)
1107 for (z=s; *z; s=z) {
1108 for ( ; *s && (isspace(*s) || *s==':'); s++);
1109 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1117 static void make_global(struct dso *p)
1119 for (; p; p=p->next) p->global = 1;
1122 static void do_mips_relocs(struct dso *p, size_t *got)
1124 size_t i, j, rel[2];
1125 unsigned char *base = p->base;
1126 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1130 while (i--) *got++ += (size_t)base;
1132 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1133 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1134 Sym *sym = p->syms + j;
1135 rel[0] = (unsigned char *)got - base;
1136 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1137 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1138 do_relocs(p, rel, sizeof rel, 2);
1142 static void reloc_all(struct dso *p)
1144 size_t dyn[DYN_CNT];
1145 for (; p; p=p->next) {
1146 if (p->relocated) continue;
1147 decode_vec(p->dynv, dyn, DYN_CNT);
1148 if (NEED_MIPS_GOT_RELOCS)
1149 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1150 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1151 2+(dyn[DT_PLTREL]==DT_RELA));
1152 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1153 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1155 if (head != &ldso && p->relro_start != p->relro_end &&
1156 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1157 && errno != ENOSYS) {
1158 error("Error relocating %s: RELRO protection failed: %m",
1160 if (runtime) longjmp(*rtld_fail, 1);
1167 static void kernel_mapped_dso(struct dso *p)
1169 size_t min_addr = -1, max_addr = 0, cnt;
1171 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1172 if (ph->p_type == PT_DYNAMIC) {
1173 p->dynv = laddr(p, ph->p_vaddr);
1174 } else if (ph->p_type == PT_GNU_RELRO) {
1175 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1176 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1178 if (ph->p_type != PT_LOAD) continue;
1179 if (ph->p_vaddr < min_addr)
1180 min_addr = ph->p_vaddr;
1181 if (ph->p_vaddr+ph->p_memsz > max_addr)
1182 max_addr = ph->p_vaddr+ph->p_memsz;
1184 min_addr &= -PAGE_SIZE;
1185 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1186 p->map = p->base + min_addr;
1187 p->map_len = max_addr - min_addr;
1188 p->kernel_mapped = 1;
1191 void __libc_exit_fini()
1194 size_t dyn[DYN_CNT];
1195 for (p=fini_head; p; p=p->fini_next) {
1196 if (!p->constructed) continue;
1197 decode_vec(p->dynv, dyn, DYN_CNT);
1198 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1199 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1200 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1201 while (n--) ((void (*)(void))*--fn)();
1203 #ifndef NO_LEGACY_INITFINI
1204 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1205 fpaddr(p, dyn[DT_FINI])();
1210 static void do_init_fini(struct dso *p)
1212 size_t dyn[DYN_CNT];
1213 int need_locking = libc.threads_minus_1;
1214 /* Allow recursive calls that arise when a library calls
1215 * dlopen from one of its constructors, but block any
1216 * other threads until all ctors have finished. */
1217 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1218 for (; p; p=p->prev) {
1219 if (p->constructed) continue;
1221 decode_vec(p->dynv, dyn, DYN_CNT);
1222 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1223 p->fini_next = fini_head;
1226 #ifndef NO_LEGACY_INITFINI
1227 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1228 fpaddr(p, dyn[DT_INIT])();
1230 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1231 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1232 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1233 while (n--) ((void (*)(void))*fn++)();
1235 if (!need_locking && libc.threads_minus_1) {
1237 pthread_mutex_lock(&init_fini_lock);
1240 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1243 void __libc_start_init(void)
1248 static void dl_debug_state(void)
1252 weak_alias(dl_debug_state, _dl_debug_state);
1254 void __init_tls(size_t *auxv)
1258 __attribute__((__visibility__("hidden")))
1259 void *__tls_get_new(size_t *v)
1261 pthread_t self = __pthread_self();
1263 /* Block signals to make accessing new TLS async-signal-safe */
1265 __block_all_sigs(&set);
1266 if (v[0]<=(size_t)self->dtv[0]) {
1267 __restore_sigs(&set);
1268 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1271 /* This is safe without any locks held because, if the caller
1272 * is able to request the Nth entry of the DTV, the DSO list
1273 * must be valid at least that far out and it was synchronized
1274 * at program startup or by an already-completed call to dlopen. */
1276 for (p=head; p->tls_id != v[0]; p=p->next);
1278 /* Get new DTV space from new DSO if needed */
1279 if (v[0] > (size_t)self->dtv[0]) {
1280 void **newdtv = p->new_dtv +
1281 (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
1282 memcpy(newdtv, self->dtv,
1283 ((size_t)self->dtv[0]+1) * sizeof(void *));
1284 newdtv[0] = (void *)v[0];
1285 self->dtv = self->dtv_copy = newdtv;
1288 /* Get new TLS memory from all new DSOs up to the requested one */
1290 for (p=head; ; p=p->next) {
1291 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1292 mem = p->new_tls + (p->tls.size + p->tls.align)
1293 * a_fetch_add(&p->new_tls_idx,1);
1294 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1296 self->dtv[p->tls_id] = mem;
1297 memcpy(mem, p->tls.image, p->tls.len);
1298 if (p->tls_id == v[0]) break;
1300 __restore_sigs(&set);
1301 return mem + v[1] + DTP_OFFSET;
1304 static void update_tls_size()
1306 libc.tls_cnt = tls_cnt;
1307 libc.tls_align = tls_align;
1308 libc.tls_size = ALIGN(
1309 (1+tls_cnt) * sizeof(void *) +
1311 sizeof(struct pthread) +
1316 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1317 * following stage 2 and stage 3 functions via primitive symbolic lookup
1318 * since it does not have access to their addresses to begin with. */
1320 /* Stage 2 of the dynamic linker is called after relative relocations
1321 * have been processed. It can make function calls to static functions
1322 * and access string literals and static data, but cannot use extern
1323 * symbols. Its job is to perform symbolic relocations on the dynamic
1324 * linker itself, but some of the relocations performed may need to be
1325 * replaced later due to copy relocations in the main program. */
1327 __attribute__((__visibility__("hidden")))
1328 void __dls2(unsigned char *base, size_t *sp)
1331 void *p1 = (void *)sp[-2];
1332 void *p2 = (void *)sp[-1];
1334 size_t *auxv, aux[AUX_CNT];
1335 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1336 decode_vec(auxv, aux, AUX_CNT);
1337 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1338 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1340 app_loadmap = p2 ? p1 : 0;
1341 ldso.loadmap = p2 ? p2 : p1;
1342 ldso.base = laddr(&ldso, 0);
1346 Ehdr *ehdr = (void *)ldso.base;
1347 ldso.name = ldso.shortname = "libc.so";
1349 ldso.phnum = ehdr->e_phnum;
1350 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1351 ldso.phentsize = ehdr->e_phentsize;
1352 kernel_mapped_dso(&ldso);
1355 if (DL_FDPIC) makefuncdescs(&ldso);
1357 /* Prepare storage for to save clobbered REL addends so they
1358 * can be reused in stage 3. There should be very few. If
1359 * something goes wrong and there are a huge number, abort
1360 * instead of risking stack overflow. */
1361 size_t dyn[DYN_CNT];
1362 decode_vec(ldso.dynv, dyn, DYN_CNT);
1363 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1364 size_t rel_size = dyn[DT_RELSZ];
1365 size_t symbolic_rel_cnt = 0;
1366 apply_addends_to = rel;
1367 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1368 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1369 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1370 size_t addends[symbolic_rel_cnt+1];
1371 saved_addends = addends;
1378 /* Call dynamic linker stage-3, __dls3, looking it up
1379 * symbolically as a barrier against moving the address
1380 * load across the above relocation processing. */
1381 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1382 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1383 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1386 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1387 * fully functional. Its job is to load (if not already loaded) and
1388 * process dependencies and relocations for the main application and
1389 * transfer control to its entry point. */
1391 _Noreturn void __dls3(size_t *sp)
1393 static struct dso app, vdso;
1394 size_t aux[AUX_CNT], *auxv;
1396 char *env_preload=0;
1399 char **argv = (void *)(sp+1);
1400 char **argv_orig = argv;
1401 char **envp = argv+argc+1;
1403 /* Find aux vector just past environ[] and use it to initialize
1404 * global data that may be needed before we can make syscalls. */
1406 for (i=argc+1; argv[i]; i++);
1407 libc.auxv = auxv = (void *)(argv+i+1);
1408 decode_vec(auxv, aux, AUX_CNT);
1409 __hwcap = aux[AT_HWCAP];
1410 libc.page_size = aux[AT_PAGESZ];
1411 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1412 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1414 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1415 * use during dynamic linking. If possible it will also serve as the
1416 * thread pointer at runtime. */
1417 libc.tls_size = sizeof builtin_tls;
1418 libc.tls_align = tls_align;
1419 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1423 /* Only trust user/env if kernel says we're not suid/sgid */
1425 env_path = getenv("LD_LIBRARY_PATH");
1426 env_preload = getenv("LD_PRELOAD");
1429 /* If the main program was already loaded by the kernel,
1430 * AT_PHDR will point to some location other than the dynamic
1431 * linker's program headers. */
1432 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1433 size_t interp_off = 0;
1434 size_t tls_image = 0;
1435 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1436 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1437 app.phnum = aux[AT_PHNUM];
1438 app.phentsize = aux[AT_PHENT];
1439 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1440 if (phdr->p_type == PT_PHDR)
1441 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1442 else if (phdr->p_type == PT_INTERP)
1443 interp_off = (size_t)phdr->p_vaddr;
1444 else if (phdr->p_type == PT_TLS) {
1445 tls_image = phdr->p_vaddr;
1446 app.tls.len = phdr->p_filesz;
1447 app.tls.size = phdr->p_memsz;
1448 app.tls.align = phdr->p_align;
1451 if (DL_FDPIC) app.loadmap = app_loadmap;
1452 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1453 if (interp_off) ldso.name = laddr(&app, interp_off);
1454 if ((aux[0] & (1UL<<AT_EXECFN))
1455 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1456 app.name = (char *)aux[AT_EXECFN];
1459 kernel_mapped_dso(&app);
1462 char *ldname = argv[0];
1463 size_t l = strlen(ldname);
1464 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1466 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1467 char *opt = argv[0]+2;
1468 *argv++ = (void *)-1;
1471 } else if (!memcmp(opt, "list", 5)) {
1473 } else if (!memcmp(opt, "library-path", 12)) {
1474 if (opt[12]=='=') env_path = opt+13;
1475 else if (opt[12]) *argv = 0;
1476 else if (*argv) env_path = *argv++;
1477 } else if (!memcmp(opt, "preload", 7)) {
1478 if (opt[7]=='=') env_preload = opt+8;
1479 else if (opt[7]) *argv = 0;
1480 else if (*argv) env_preload = *argv++;
1485 argv[-1] = (void *)(argc - (argv-argv_orig));
1487 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1489 "Dynamic Program Loader\n"
1490 "Usage: %s [options] [--] pathname%s\n",
1491 __libc_get_version(), ldname,
1492 ldd_mode ? "" : " [args]");
1495 fd = open(argv[0], O_RDONLY);
1497 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1501 Ehdr *ehdr = (void *)map_library(fd, &app);
1503 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1510 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1511 /* Find the name that would have been used for the dynamic
1512 * linker had ldd not taken its place. */
1514 for (i=0; i<app.phnum; i++) {
1515 if (app.phdr[i].p_type == PT_INTERP)
1516 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1518 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1522 libc.tls_head = tls_tail = &app.tls;
1523 app.tls_id = tls_cnt = 1;
1526 tls_offset = app.tls.size
1527 + ( -((uintptr_t)app.tls.image + app.tls.size)
1528 & (app.tls.align-1) );
1530 tls_offset = app.tls.offset = app.tls.size
1531 + ( -((uintptr_t)app.tls.image + app.tls.size)
1532 & (app.tls.align-1) );
1534 tls_align = MAXP2(tls_align, app.tls.align);
1539 makefuncdescs(&app);
1541 app.loadmap = (void *)&app_dummy_loadmap;
1542 app.loadmap->nsegs = 1;
1543 app.loadmap->segs[0].addr = (size_t)app.map;
1544 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1546 app.loadmap->segs[0].p_memsz = app.map_len;
1548 argv[-3] = (void *)app.loadmap;
1551 /* Attach to vdso, if provided by the kernel */
1552 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1553 Ehdr *ehdr = (void *)vdso_base;
1554 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1555 vdso.phnum = ehdr->e_phnum;
1556 vdso.phentsize = ehdr->e_phentsize;
1557 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1558 if (phdr->p_type == PT_DYNAMIC)
1559 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1560 if (phdr->p_type == PT_LOAD)
1561 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1564 vdso.shortname = "linux-gate.so.1";
1572 /* Initial dso chain consists only of the app. */
1575 /* Donate unused parts of app and library mapping to malloc */
1577 reclaim_gaps(&ldso);
1579 /* Load preload/needed libraries, add their symbols to the global
1580 * namespace, and perform all remaining relocations. */
1581 if (env_preload) load_preload(env_preload);
1585 for (i=0; app.dynv[i]; i+=2) {
1586 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1587 app.dynv[i+1] = (size_t)&debug;
1588 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1589 size_t *ptr = (size_t *) app.dynv[i+1];
1590 *ptr = (size_t)&debug;
1594 /* The main program must be relocated LAST since it may contin
1595 * copy relocations which depend on libraries' relocations. */
1596 reloc_all(app.next);
1600 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1601 void *initial_tls = calloc(libc.tls_size, 1);
1603 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1604 argv[0], libc.tls_size);
1607 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1611 size_t tmp_tls_size = libc.tls_size;
1612 pthread_t self = __pthread_self();
1613 /* Temporarily set the tls size to the full size of
1614 * builtin_tls so that __copy_tls will use the same layout
1615 * as it did for before. Then check, just to be safe. */
1616 libc.tls_size = sizeof builtin_tls;
1617 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1618 libc.tls_size = tmp_tls_size;
1620 static_tls_cnt = tls_cnt;
1622 if (ldso_fail) _exit(127);
1623 if (ldd_mode) _exit(0);
1625 /* Switch to runtime mode: any further failures in the dynamic
1626 * linker are a reportable failure rather than a fatal startup
1631 debug.bp = dl_debug_state;
1633 debug.base = ldso.base;
1639 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1643 void *dlopen(const char *file, int mode)
1645 struct dso *volatile p, *orig_tail, *next;
1646 struct tls_module *orig_tls_tail;
1647 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1652 if (!file) return head;
1654 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1655 pthread_rwlock_wrlock(&lock);
1659 orig_tls_tail = tls_tail;
1660 orig_tls_cnt = tls_cnt;
1661 orig_tls_offset = tls_offset;
1662 orig_tls_align = tls_align;
1664 noload = mode & RTLD_NOLOAD;
1667 if (setjmp(*rtld_fail)) {
1668 /* Clean up anything new that was (partially) loaded */
1669 if (p && p->deps) for (i=0; p->deps[i]; i++)
1670 if (p->deps[i]->global < 0)
1671 p->deps[i]->global = 0;
1672 for (p=orig_tail->next; p; p=next) {
1674 while (p->td_index) {
1675 void *tmp = p->td_index->next;
1680 if (p->rpath != p->rpath_orig)
1686 if (!orig_tls_tail) libc.tls_head = 0;
1687 tls_tail = orig_tls_tail;
1688 tls_cnt = orig_tls_cnt;
1689 tls_offset = orig_tls_offset;
1690 tls_align = orig_tls_align;
1695 } else p = load_library(file, head);
1699 "Library %s is not already loaded" :
1700 "Error loading shared library %s: %m",
1705 /* First load handling */
1708 if (p->deps) for (i=0; p->deps[i]; i++)
1709 if (!p->deps[i]->global)
1710 p->deps[i]->global = -1;
1711 if (!p->global) p->global = -1;
1713 if (p->deps) for (i=0; p->deps[i]; i++)
1714 if (p->deps[i]->global < 0)
1715 p->deps[i]->global = 0;
1716 if (p->global < 0) p->global = 0;
1719 if (mode & RTLD_GLOBAL) {
1720 if (p->deps) for (i=0; p->deps[i]; i++)
1721 p->deps[i]->global = 1;
1731 pthread_rwlock_unlock(&lock);
1732 if (p) do_init_fini(orig_tail);
1733 pthread_setcancelstate(cs, 0);
1737 __attribute__((__visibility__("hidden")))
1738 int __dl_invalid_handle(void *h)
1741 for (p=head; p; p=p->next) if (h==p) return 0;
1742 error("Invalid library handle %p", (void *)h);
1746 static void *addr2dso(size_t a)
1750 if (DL_FDPIC) for (p=head; p; p=p->next) {
1752 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1755 for (p=head; p; p=p->next) {
1756 if (DL_FDPIC && p->loadmap) {
1757 for (i=0; i<p->loadmap->nsegs; i++) {
1758 if (a-p->loadmap->segs[i].p_vaddr
1759 < p->loadmap->segs[i].p_memsz)
1763 if (a-(size_t)p->map < p->map_len)
1770 void *__tls_get_addr(size_t *);
1772 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1775 uint32_t h = 0, gh = 0, *ght;
1777 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1778 if (p == RTLD_DEFAULT) {
1780 } else if (p == RTLD_NEXT) {
1781 p = addr2dso((size_t)ra);
1785 struct symdef def = find_sym(p, s, 0);
1786 if (!def.sym) goto failed;
1787 if ((def.sym->st_info&0xf) == STT_TLS)
1788 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1789 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1790 return def.dso->funcdescs + (def.sym - def.dso->syms);
1791 return laddr(def.dso, def.sym->st_value);
1793 if (__dl_invalid_handle(p))
1795 if ((ght = p->ghashtab)) {
1797 sym = gnu_lookup(gh, ght, p, s);
1800 sym = sysv_lookup(s, h, p);
1802 if (sym && (sym->st_info&0xf) == STT_TLS)
1803 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1804 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1805 return p->funcdescs + (sym - p->syms);
1806 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1807 return laddr(p, sym->st_value);
1808 if (p->deps) for (i=0; p->deps[i]; i++) {
1809 if ((ght = p->deps[i]->ghashtab)) {
1810 if (!gh) gh = gnu_hash(s);
1811 sym = gnu_lookup(gh, ght, p->deps[i], s);
1813 if (!h) h = sysv_hash(s);
1814 sym = sysv_lookup(s, h, p->deps[i]);
1816 if (sym && (sym->st_info&0xf) == STT_TLS)
1817 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1818 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1819 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1820 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1821 return laddr(p->deps[i], sym->st_value);
1824 error("Symbol not found: %s", s);
1828 int dladdr(const void *addr, Dl_info *info)
1836 pthread_rwlock_rdlock(&lock);
1837 p = addr2dso((size_t)addr);
1838 pthread_rwlock_unlock(&lock);
1843 strings = p->strings;
1844 nsym = count_syms(p);
1847 size_t idx = ((size_t)addr-(size_t)p->funcdescs)
1848 / sizeof(*p->funcdescs);
1849 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1850 best = p->funcdescs + idx;
1851 bestsym = sym + idx;
1855 if (!best) for (; nsym; nsym--, sym++) {
1857 && (1<<(sym->st_info&0xf) & OK_TYPES)
1858 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1859 void *symaddr = laddr(p, sym->st_value);
1860 if (symaddr > addr || symaddr < best)
1864 if (addr == symaddr)
1869 if (!best) return 0;
1871 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
1872 best = p->funcdescs + (bestsym - p->syms);
1874 info->dli_fname = p->name;
1875 info->dli_fbase = p->base;
1876 info->dli_sname = strings + bestsym->st_name;
1877 info->dli_saddr = best;
1882 __attribute__((__visibility__("hidden")))
1883 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1886 pthread_rwlock_rdlock(&lock);
1887 res = do_dlsym(p, s, ra);
1888 pthread_rwlock_unlock(&lock);
1892 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1894 struct dso *current;
1895 struct dl_phdr_info info;
1897 for(current = head; current;) {
1898 info.dlpi_addr = (uintptr_t)current->base;
1899 info.dlpi_name = current->name;
1900 info.dlpi_phdr = current->phdr;
1901 info.dlpi_phnum = current->phnum;
1902 info.dlpi_adds = gencnt;
1904 info.dlpi_tls_modid = current->tls_id;
1905 info.dlpi_tls_data = current->tls.image;
1907 ret = (callback)(&info, sizeof (info), data);
1909 if (ret != 0) break;
1911 pthread_rwlock_rdlock(&lock);
1912 current = current->next;
1913 pthread_rwlock_unlock(&lock);
1918 __attribute__((__visibility__("hidden")))
1919 void __dl_vseterr(const char *, va_list);
1921 static void error(const char *fmt, ...)
1926 vdprintf(2, fmt, ap);
1932 __dl_vseterr(fmt, ap);