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;
69 struct dso **deps, *needed_by;
70 char *rpath_orig, *rpath;
71 struct tls_module tls;
73 size_t relro_start, relro_end;
75 unsigned char *new_tls;
76 volatile int new_dtv_idx, new_tls_idx;
77 struct td_index *td_index;
78 struct dso *fini_next;
83 struct fdpic_loadmap *loadmap;
98 int __init_tp(void *);
99 void __init_libc(char **, char *);
100 void *__copy_tls(unsigned char *);
102 __attribute__((__visibility__("hidden")))
103 const char *__libc_get_version(void);
105 static struct builtin_tls {
110 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
112 #define ADDEND_LIMIT 4096
113 static size_t *saved_addends, *apply_addends_to;
115 static struct dso ldso;
116 static struct dso *head, *tail, *fini_head, *syms_tail;
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 Elf_Symndx *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->syms_next) {
266 if ((ght = dso->ghashtab)) {
269 int maskbits = 8 * sizeof ghm;
271 ghm = 1ul << gh % maskbits;
273 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
275 if (!h) h = sysv_hash(s);
276 sym = sysv_lookup(s, h, dso);
280 if (need_def || (sym->st_info&0xf) == STT_TLS
281 || ARCH_SYM_REJECT_UND(sym))
284 if ((sym->st_info&0xf) != STT_TLS)
286 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
287 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
295 __attribute__((__visibility__("hidden")))
296 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
298 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
300 unsigned char *base = dso->base;
301 Sym *syms = dso->syms;
302 char *strings = dso->strings;
313 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
316 /* Only ldso's REL table needs addend saving/reuse. */
317 if (rel == apply_addends_to)
322 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
323 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
324 type = R_TYPE(rel[1]);
325 if (type == REL_NONE) continue;
326 sym_index = R_SYM(rel[1]);
327 reloc_addr = laddr(dso, rel[0]);
329 sym = syms + sym_index;
330 name = strings + sym->st_name;
331 ctx = type==REL_COPY ? head->syms_next : head;
332 def = (sym->st_info&0xf) == STT_SECTION
333 ? (struct symdef){ .dso = dso, .sym = sym }
334 : find_sym(ctx, name, type==REL_PLT);
335 if (!def.sym && (sym->st_shndx != SHN_UNDEF
336 || sym->st_info>>4 != STB_WEAK)) {
337 error("Error relocating %s: %s: symbol not found",
339 if (runtime) longjmp(*rtld_fail, 1);
350 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
352 } else if (reuse_addends) {
353 /* Save original addend in stage 2 where the dso
354 * chain consists of just ldso; otherwise read back
355 * saved addend since the inline one was clobbered. */
357 saved_addends[save_slot] = *reloc_addr;
358 addend = saved_addends[save_slot++];
360 addend = *reloc_addr;
363 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
364 tls_val = def.sym ? def.sym->st_value : 0;
370 addend -= (size_t)reloc_addr;
374 *reloc_addr = sym_val + addend;
377 *reloc_addr = (size_t)base + addend;
380 if (sym) *reloc_addr = sym_val + addend;
381 else *reloc_addr = (size_t)base + addend;
384 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
387 *(uint32_t *)reloc_addr = sym_val + addend
388 - (size_t)reloc_addr;
391 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
392 + (def.sym - def.dso->syms)) : 0;
394 case REL_FUNCDESC_VAL:
395 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
396 else *reloc_addr = sym_val;
397 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
400 *reloc_addr = def.dso->tls_id;
403 *reloc_addr = tls_val + addend - DTP_OFFSET;
407 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
411 *reloc_addr = tls_val - def.dso->tls.offset + addend;
414 *reloc_addr = def.dso->tls.offset - tls_val + addend;
418 if (stride<3) addend = reloc_addr[1];
419 if (runtime && def.dso->tls_id >= static_tls_cnt) {
420 struct td_index *new = malloc(sizeof *new);
423 "Error relocating %s: cannot allocate TLSDESC for %s",
424 dso->name, sym ? name : "(local)" );
425 longjmp(*rtld_fail, 1);
427 new->next = dso->td_index;
429 new->args[0] = def.dso->tls_id;
430 new->args[1] = tls_val + addend;
431 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
432 reloc_addr[1] = (size_t)new;
434 reloc_addr[0] = (size_t)__tlsdesc_static;
436 reloc_addr[1] = tls_val + def.dso->tls.offset
439 reloc_addr[1] = tls_val - def.dso->tls.offset
445 error("Error relocating %s: unsupported relocation type %d",
447 if (runtime) longjmp(*rtld_fail, 1);
453 /* A huge hack: to make up for the wastefulness of shared libraries
454 * needing at least a page of dirty memory even if they have no global
455 * data, we reclaim the gaps at the beginning and end of writable maps
456 * and "donate" them to the heap by setting up minimal malloc
457 * structures and then freeing them. */
459 static void reclaim(struct dso *dso, size_t start, size_t end)
462 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
463 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
464 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
465 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
466 if (start>end || end-start < 4*sizeof(size_t)) return;
467 a = laddr(dso, start);
470 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
475 static void reclaim_gaps(struct dso *dso)
477 Phdr *ph = dso->phdr;
478 size_t phcnt = dso->phnum;
480 if (DL_FDPIC) return; // FIXME
481 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
482 if (ph->p_type!=PT_LOAD) continue;
483 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
484 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
485 reclaim(dso, ph->p_vaddr+ph->p_memsz,
486 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
490 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
492 static int no_map_fixed;
495 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
496 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
500 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
501 if (flags & MAP_ANONYMOUS) {
506 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
507 for (q=p; n; q+=r, off+=r, n-=r) {
509 if (r < 0 && errno != EINTR) return MAP_FAILED;
518 static void unmap_library(struct dso *dso)
522 for (i=0; i<dso->loadmap->nsegs; i++) {
523 if (!dso->loadmap->segs[i].p_memsz)
525 munmap((void *)dso->loadmap->segs[i].addr,
526 dso->loadmap->segs[i].p_memsz);
529 } else if (dso->map && dso->map_len) {
530 munmap(dso->map, dso->map_len);
534 static void *map_library(int fd, struct dso *dso)
536 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
537 void *allocated_buf=0;
539 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
540 size_t this_min, this_max;
546 unsigned char *map=MAP_FAILED, *base;
551 ssize_t l = read(fd, buf, sizeof buf);
554 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
556 phsize = eh->e_phentsize * eh->e_phnum;
557 if (phsize > sizeof buf - sizeof *eh) {
558 allocated_buf = malloc(phsize);
559 if (!allocated_buf) return 0;
560 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
561 if (l < 0) goto error;
562 if (l != phsize) goto noexec;
563 ph = ph0 = allocated_buf;
564 } else if (eh->e_phoff + phsize > l) {
565 l = pread(fd, buf+1, phsize, eh->e_phoff);
566 if (l < 0) goto error;
567 if (l != phsize) goto noexec;
568 ph = ph0 = (void *)(buf + 1);
570 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
572 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
573 if (ph->p_type == PT_DYNAMIC) {
575 } else if (ph->p_type == PT_TLS) {
576 tls_image = ph->p_vaddr;
577 dso->tls.align = ph->p_align;
578 dso->tls.len = ph->p_filesz;
579 dso->tls.size = ph->p_memsz;
580 } else if (ph->p_type == PT_GNU_RELRO) {
581 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
582 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
584 if (ph->p_type != PT_LOAD) continue;
586 if (ph->p_vaddr < addr_min) {
587 addr_min = ph->p_vaddr;
588 off_start = ph->p_offset;
589 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
590 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
591 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
593 if (ph->p_vaddr+ph->p_memsz > addr_max) {
594 addr_max = ph->p_vaddr+ph->p_memsz;
597 if (!dyn) goto noexec;
598 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
599 dso->loadmap = calloc(1, sizeof *dso->loadmap
600 + nsegs * sizeof *dso->loadmap->segs);
601 if (!dso->loadmap) goto error;
602 dso->loadmap->nsegs = nsegs;
603 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
604 if (ph->p_type != PT_LOAD) continue;
605 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
606 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
607 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
608 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
610 fd, ph->p_offset & -PAGE_SIZE);
611 if (map == MAP_FAILED) {
615 dso->loadmap->segs[i].addr = (size_t)map +
616 (ph->p_vaddr & PAGE_SIZE-1);
617 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
618 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
620 if (prot & PROT_WRITE) {
621 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
623 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
624 size_t pgend = brk + ph->p_memsz - ph->p_filesz
625 + PAGE_SIZE-1 & -PAGE_SIZE;
626 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
628 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
629 -1, off_start) == MAP_FAILED)
631 memset(map + brk, 0, pgbrk-brk);
634 map = (void *)dso->loadmap->segs[0].addr;
638 addr_max += PAGE_SIZE-1;
639 addr_max &= -PAGE_SIZE;
640 addr_min &= -PAGE_SIZE;
641 off_start &= -PAGE_SIZE;
642 map_len = addr_max - addr_min + off_start;
643 /* The first time, we map too much, possibly even more than
644 * the length of the file. This is okay because we will not
645 * use the invalid part; we just need to reserve the right
646 * amount of virtual address space to map over later. */
647 map = DL_NOMMU_SUPPORT
648 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
649 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
650 : mmap((void *)addr_min, map_len, prot,
651 MAP_PRIVATE, fd, off_start);
652 if (map==MAP_FAILED) goto error;
654 dso->map_len = map_len;
655 /* If the loaded file is not relocatable and the requested address is
656 * not available, then the load operation must fail. */
657 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
661 base = map - addr_min;
664 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
665 if (ph->p_type != PT_LOAD) continue;
666 /* Check if the programs headers are in this load segment, and
667 * if so, record the address for use by dl_iterate_phdr. */
668 if (!dso->phdr && eh->e_phoff >= ph->p_offset
669 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
670 dso->phdr = (void *)(base + ph->p_vaddr
671 + (eh->e_phoff-ph->p_offset));
672 dso->phnum = eh->e_phnum;
673 dso->phentsize = eh->e_phentsize;
675 /* Reuse the existing mapping for the lowest-address LOAD */
676 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT)
678 this_min = ph->p_vaddr & -PAGE_SIZE;
679 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
680 off_start = ph->p_offset & -PAGE_SIZE;
681 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
682 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
683 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
684 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
686 if (ph->p_memsz > ph->p_filesz) {
687 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
688 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
689 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
690 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)
694 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
695 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
696 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
703 dso->dynv = laddr(dso, dyn);
704 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
705 if (!runtime) reclaim_gaps(dso);
711 if (map!=MAP_FAILED) unmap_library(dso);
716 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
721 s += strspn(s, ":\n");
722 l = strcspn(s, ":\n");
723 if (l-1 >= INT_MAX) return -1;
724 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
725 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
733 /* Any negative value but -1 will inhibit
734 * futher path search. */
742 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
745 const char *s, *t, *origin;
747 if (p->rpath || !p->rpath_orig) return 0;
748 if (!strchr(p->rpath_orig, '$')) {
749 p->rpath = p->rpath_orig;
754 while ((t=strchr(s, '$'))) {
755 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
760 if (n > SSIZE_MAX/PATH_MAX) return 0;
762 if (p->kernel_mapped) {
763 /* $ORIGIN searches cannot be performed for the main program
764 * when it is suid/sgid/AT_SECURE. This is because the
765 * pathname is under the control of the caller of execve.
766 * For libraries, however, $ORIGIN can be processed safely
767 * since the library's pathname came from a trusted source
768 * (either system paths or a call to dlopen). */
771 l = readlink("/proc/self/exe", buf, buf_size);
772 if (l == -1) switch (errno) {
787 t = strrchr(origin, '/');
788 l = t ? t-origin : 0;
789 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
790 if (!p->rpath) return -1;
794 while ((t=strchr(s, '$'))) {
797 memcpy(d, origin, l);
799 /* It was determined previously that the '$' is followed
800 * either by "ORIGIN" or "{ORIGIN}". */
801 s = t + 7 + 2*(t[1]=='{');
807 static void decode_dyn(struct dso *p)
810 decode_vec(p->dynv, dyn, DYN_CNT);
811 p->syms = laddr(p, dyn[DT_SYMTAB]);
812 p->strings = laddr(p, dyn[DT_STRTAB]);
813 if (dyn[0]&(1<<DT_HASH))
814 p->hashtab = laddr(p, dyn[DT_HASH]);
815 if (dyn[0]&(1<<DT_RPATH))
816 p->rpath_orig = p->strings + dyn[DT_RPATH];
817 if (dyn[0]&(1<<DT_RUNPATH))
818 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
819 if (dyn[0]&(1<<DT_PLTGOT))
820 p->got = laddr(p, dyn[DT_PLTGOT]);
821 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
822 p->ghashtab = laddr(p, *dyn);
823 if (search_vec(p->dynv, dyn, DT_VERSYM))
824 p->versym = laddr(p, *dyn);
827 static size_t count_syms(struct dso *p)
829 if (p->hashtab) return p->hashtab[1];
832 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
834 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
835 if (buckets[i] > nsym)
839 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
841 while (!(*hashval++ & 1));
846 static void *dl_mmap(size_t n)
849 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
851 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
853 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
855 return p == MAP_FAILED ? 0 : p;
858 static void makefuncdescs(struct dso *p)
860 static int self_done;
861 size_t nsym = count_syms(p);
862 size_t i, size = nsym * sizeof(*p->funcdescs);
865 p->funcdescs = dl_mmap(size);
868 p->funcdescs = malloc(size);
871 if (!runtime) a_crash();
872 error("Error allocating function descriptors for %s", p->name);
873 longjmp(*rtld_fail, 1);
875 for (i=0; i<nsym; i++) {
876 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
877 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
878 p->funcdescs[i].got = p->got;
880 p->funcdescs[i].addr = 0;
881 p->funcdescs[i].got = 0;
886 static struct dso *load_library(const char *name, struct dso *needed_by)
888 char buf[2*NAME_MAX+2];
889 const char *pathname;
891 struct dso *p, temp_dso = {0};
903 /* Catch and block attempts to reload the implementation itself */
904 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
905 static const char reserved[] =
906 "c.pthread.rt.m.dl.util.xnet.";
907 const char *rp, *next;
908 for (rp=reserved; *rp; rp=next) {
909 next = strchr(rp, '.') + 1;
910 if (strncmp(name+3, rp, next-rp) == 0)
915 /* Track which names have been resolved
916 * and only report each one once. */
917 static unsigned reported;
918 unsigned mask = 1U<<(rp-reserved);
919 if (!(reported & mask)) {
921 dprintf(1, "\t%s => %s (%p)\n",
929 if (!strcmp(name, ldso.name)) is_self = 1;
938 if (strchr(name, '/')) {
940 fd = open(name, O_RDONLY|O_CLOEXEC);
942 /* Search for the name to see if it's already loaded */
943 for (p=head->next; p; p=p->next) {
944 if (p->shortname && !strcmp(p->shortname, name)) {
949 if (strlen(name) > NAME_MAX) return 0;
951 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
952 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
953 if (fixup_rpath(p, buf, sizeof buf) < 0)
954 fd = -2; /* Inhibit further search. */
956 fd = path_open(name, p->rpath, buf, sizeof buf);
962 if (ldso.name[0]=='/') {
964 for (s=t=z=ldso.name; *s; s++)
965 if (*s=='/') z=t, t=s;
966 prefix_len = z-ldso.name;
967 if (prefix_len < PATH_MAX)
974 char etc_ldso_path[prefix_len + 1
975 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
976 snprintf(etc_ldso_path, sizeof etc_ldso_path,
977 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
978 (int)prefix_len, prefix);
979 FILE *f = fopen(etc_ldso_path, "rbe");
981 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
986 } else if (errno != ENOENT) {
990 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
991 fd = path_open(name, sys_path, buf, sizeof buf);
995 if (fd < 0) return 0;
996 if (fstat(fd, &st) < 0) {
1000 for (p=head->next; p; p=p->next) {
1001 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1002 /* If this library was previously loaded with a
1003 * pathname but a search found the same inode,
1004 * setup its shortname so it can be found by name. */
1005 if (!p->shortname && pathname != name)
1006 p->shortname = strrchr(p->name, '/')+1;
1012 map = noload ? 0 : map_library(fd, &temp_dso);
1016 /* Allocate storage for the new DSO. When there is TLS, this
1017 * storage must include a reservation for all pre-existing
1018 * threads to obtain copies of both the new TLS, and an
1019 * extended DTV capable of storing an additional slot for
1020 * the newly-loaded DSO. */
1021 alloc_size = sizeof *p + strlen(pathname) + 1;
1022 if (runtime && temp_dso.tls.image) {
1023 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1024 + sizeof(void *) * (tls_cnt+3);
1025 n_th = libc.threads_minus_1 + 1;
1026 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1027 else alloc_size += n_th * per_th;
1029 p = calloc(1, alloc_size);
1031 unmap_library(&temp_dso);
1034 memcpy(p, &temp_dso, sizeof temp_dso);
1039 p->needed_by = needed_by;
1041 strcpy(p->name, pathname);
1042 /* Add a shortname only if name arg was not an explicit pathname. */
1043 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1045 p->tls_id = ++tls_cnt;
1046 tls_align = MAXP2(tls_align, p->tls.align);
1048 p->tls.offset = tls_offset + ( (tls_align-1) &
1049 -(tls_offset + (uintptr_t)p->tls.image) );
1050 tls_offset += p->tls.size;
1052 tls_offset += p->tls.size + p->tls.align - 1;
1053 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1055 p->tls.offset = tls_offset;
1057 p->new_dtv = (void *)(-sizeof(size_t) &
1058 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1059 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1060 if (tls_tail) tls_tail->next = &p->tls;
1061 else libc.tls_head = &p->tls;
1069 if (DL_FDPIC) makefuncdescs(p);
1071 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1076 static void load_deps(struct dso *p)
1079 struct dso ***deps = &p->deps, **tmp, *dep;
1080 for (; p; p=p->next) {
1081 for (i=0; p->dynv[i]; i+=2) {
1082 if (p->dynv[i] != DT_NEEDED) continue;
1083 dep = load_library(p->strings + p->dynv[i+1], p);
1085 error("Error loading shared library %s: %m (needed by %s)",
1086 p->strings + p->dynv[i+1], p->name);
1087 if (runtime) longjmp(*rtld_fail, 1);
1091 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1092 if (!tmp) longjmp(*rtld_fail, 1);
1101 static void load_preload(char *s)
1105 for (z=s; *z; s=z) {
1106 for ( ; *s && (isspace(*s) || *s==':'); s++);
1107 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1115 static void add_syms(struct dso *p)
1117 if (!p->syms_next && syms_tail != p) {
1118 syms_tail->syms_next = p;
1123 static void revert_syms(struct dso *old_tail)
1125 struct dso *p, *next;
1126 /* Chop off the tail of the list of dsos that participate in
1127 * the global symbol table, reverting them to RTLD_LOCAL. */
1128 for (p=old_tail; p; p=next) {
1129 next = p->syms_next;
1132 syms_tail = old_tail;
1135 static void do_mips_relocs(struct dso *p, size_t *got)
1137 size_t i, j, rel[2];
1138 unsigned char *base = p->base;
1139 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1143 while (i--) *got++ += (size_t)base;
1145 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1146 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1147 Sym *sym = p->syms + j;
1148 rel[0] = (unsigned char *)got - base;
1149 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1150 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1151 do_relocs(p, rel, sizeof rel, 2);
1155 static void reloc_all(struct dso *p)
1157 size_t dyn[DYN_CNT];
1158 for (; p; p=p->next) {
1159 if (p->relocated) continue;
1160 decode_vec(p->dynv, dyn, DYN_CNT);
1161 if (NEED_MIPS_GOT_RELOCS)
1162 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1163 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1164 2+(dyn[DT_PLTREL]==DT_RELA));
1165 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1166 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1168 if (head != &ldso && p->relro_start != p->relro_end &&
1169 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1170 && errno != ENOSYS) {
1171 error("Error relocating %s: RELRO protection failed: %m",
1173 if (runtime) longjmp(*rtld_fail, 1);
1180 static void kernel_mapped_dso(struct dso *p)
1182 size_t min_addr = -1, max_addr = 0, cnt;
1184 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1185 if (ph->p_type == PT_DYNAMIC) {
1186 p->dynv = laddr(p, ph->p_vaddr);
1187 } else if (ph->p_type == PT_GNU_RELRO) {
1188 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1189 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1191 if (ph->p_type != PT_LOAD) continue;
1192 if (ph->p_vaddr < min_addr)
1193 min_addr = ph->p_vaddr;
1194 if (ph->p_vaddr+ph->p_memsz > max_addr)
1195 max_addr = ph->p_vaddr+ph->p_memsz;
1197 min_addr &= -PAGE_SIZE;
1198 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1199 p->map = p->base + min_addr;
1200 p->map_len = max_addr - min_addr;
1201 p->kernel_mapped = 1;
1204 void __libc_exit_fini()
1207 size_t dyn[DYN_CNT];
1208 for (p=fini_head; p; p=p->fini_next) {
1209 if (!p->constructed) continue;
1210 decode_vec(p->dynv, dyn, DYN_CNT);
1211 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1212 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1213 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1214 while (n--) ((void (*)(void))*--fn)();
1216 #ifndef NO_LEGACY_INITFINI
1217 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1218 fpaddr(p, dyn[DT_FINI])();
1223 static void do_init_fini(struct dso *p)
1225 size_t dyn[DYN_CNT];
1226 int need_locking = libc.threads_minus_1;
1227 /* Allow recursive calls that arise when a library calls
1228 * dlopen from one of its constructors, but block any
1229 * other threads until all ctors have finished. */
1230 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1231 for (; p; p=p->prev) {
1232 if (p->constructed) continue;
1234 decode_vec(p->dynv, dyn, DYN_CNT);
1235 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1236 p->fini_next = fini_head;
1239 #ifndef NO_LEGACY_INITFINI
1240 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1241 fpaddr(p, dyn[DT_INIT])();
1243 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1244 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1245 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1246 while (n--) ((void (*)(void))*fn++)();
1248 if (!need_locking && libc.threads_minus_1) {
1250 pthread_mutex_lock(&init_fini_lock);
1253 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1256 void __libc_start_init(void)
1261 static void dl_debug_state(void)
1265 weak_alias(dl_debug_state, _dl_debug_state);
1267 void __init_tls(size_t *auxv)
1271 __attribute__((__visibility__("hidden")))
1272 void *__tls_get_new(tls_mod_off_t *v)
1274 pthread_t self = __pthread_self();
1276 /* Block signals to make accessing new TLS async-signal-safe */
1278 __block_all_sigs(&set);
1279 if (v[0]<=(size_t)self->dtv[0]) {
1280 __restore_sigs(&set);
1281 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1284 /* This is safe without any locks held because, if the caller
1285 * is able to request the Nth entry of the DTV, the DSO list
1286 * must be valid at least that far out and it was synchronized
1287 * at program startup or by an already-completed call to dlopen. */
1289 for (p=head; p->tls_id != v[0]; p=p->next);
1291 /* Get new DTV space from new DSO if needed */
1292 if (v[0] > (size_t)self->dtv[0]) {
1293 void **newdtv = p->new_dtv +
1294 (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
1295 memcpy(newdtv, self->dtv,
1296 ((size_t)self->dtv[0]+1) * sizeof(void *));
1297 newdtv[0] = (void *)v[0];
1298 self->dtv = self->dtv_copy = newdtv;
1301 /* Get new TLS memory from all new DSOs up to the requested one */
1303 for (p=head; ; p=p->next) {
1304 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1305 mem = p->new_tls + (p->tls.size + p->tls.align)
1306 * a_fetch_add(&p->new_tls_idx,1);
1307 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1309 self->dtv[p->tls_id] = mem;
1310 memcpy(mem, p->tls.image, p->tls.len);
1311 if (p->tls_id == v[0]) break;
1313 __restore_sigs(&set);
1314 return mem + v[1] + DTP_OFFSET;
1317 static void update_tls_size()
1319 libc.tls_cnt = tls_cnt;
1320 libc.tls_align = tls_align;
1321 libc.tls_size = ALIGN(
1322 (1+tls_cnt) * sizeof(void *) +
1324 sizeof(struct pthread) +
1329 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1330 * following stage 2 and stage 3 functions via primitive symbolic lookup
1331 * since it does not have access to their addresses to begin with. */
1333 /* Stage 2 of the dynamic linker is called after relative relocations
1334 * have been processed. It can make function calls to static functions
1335 * and access string literals and static data, but cannot use extern
1336 * symbols. Its job is to perform symbolic relocations on the dynamic
1337 * linker itself, but some of the relocations performed may need to be
1338 * replaced later due to copy relocations in the main program. */
1340 __attribute__((__visibility__("hidden")))
1341 void __dls2(unsigned char *base, size_t *sp)
1344 void *p1 = (void *)sp[-2];
1345 void *p2 = (void *)sp[-1];
1347 size_t *auxv, aux[AUX_CNT];
1348 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1349 decode_vec(auxv, aux, AUX_CNT);
1350 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1351 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1353 app_loadmap = p2 ? p1 : 0;
1354 ldso.loadmap = p2 ? p2 : p1;
1355 ldso.base = laddr(&ldso, 0);
1359 Ehdr *ehdr = (void *)ldso.base;
1360 ldso.name = ldso.shortname = "libc.so";
1361 ldso.phnum = ehdr->e_phnum;
1362 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1363 ldso.phentsize = ehdr->e_phentsize;
1364 kernel_mapped_dso(&ldso);
1367 if (DL_FDPIC) makefuncdescs(&ldso);
1369 /* Prepare storage for to save clobbered REL addends so they
1370 * can be reused in stage 3. There should be very few. If
1371 * something goes wrong and there are a huge number, abort
1372 * instead of risking stack overflow. */
1373 size_t dyn[DYN_CNT];
1374 decode_vec(ldso.dynv, dyn, DYN_CNT);
1375 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1376 size_t rel_size = dyn[DT_RELSZ];
1377 size_t symbolic_rel_cnt = 0;
1378 apply_addends_to = rel;
1379 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1380 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1381 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1382 size_t addends[symbolic_rel_cnt+1];
1383 saved_addends = addends;
1390 /* Call dynamic linker stage-3, __dls3, looking it up
1391 * symbolically as a barrier against moving the address
1392 * load across the above relocation processing. */
1393 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1394 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1395 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1398 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1399 * fully functional. Its job is to load (if not already loaded) and
1400 * process dependencies and relocations for the main application and
1401 * transfer control to its entry point. */
1403 _Noreturn void __dls3(size_t *sp)
1405 static struct dso app, vdso;
1406 size_t aux[AUX_CNT], *auxv;
1408 char *env_preload=0;
1411 char **argv = (void *)(sp+1);
1412 char **argv_orig = argv;
1413 char **envp = argv+argc+1;
1415 /* Find aux vector just past environ[] and use it to initialize
1416 * global data that may be needed before we can make syscalls. */
1418 for (i=argc+1; argv[i]; i++);
1419 libc.auxv = auxv = (void *)(argv+i+1);
1420 decode_vec(auxv, aux, AUX_CNT);
1421 __hwcap = aux[AT_HWCAP];
1422 libc.page_size = aux[AT_PAGESZ];
1423 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1424 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1426 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1427 * use during dynamic linking. If possible it will also serve as the
1428 * thread pointer at runtime. */
1429 libc.tls_size = sizeof builtin_tls;
1430 libc.tls_align = tls_align;
1431 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1435 /* Only trust user/env if kernel says we're not suid/sgid */
1437 env_path = getenv("LD_LIBRARY_PATH");
1438 env_preload = getenv("LD_PRELOAD");
1441 /* If the main program was already loaded by the kernel,
1442 * AT_PHDR will point to some location other than the dynamic
1443 * linker's program headers. */
1444 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1445 size_t interp_off = 0;
1446 size_t tls_image = 0;
1447 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1448 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1449 app.phnum = aux[AT_PHNUM];
1450 app.phentsize = aux[AT_PHENT];
1451 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1452 if (phdr->p_type == PT_PHDR)
1453 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1454 else if (phdr->p_type == PT_INTERP)
1455 interp_off = (size_t)phdr->p_vaddr;
1456 else if (phdr->p_type == PT_TLS) {
1457 tls_image = phdr->p_vaddr;
1458 app.tls.len = phdr->p_filesz;
1459 app.tls.size = phdr->p_memsz;
1460 app.tls.align = phdr->p_align;
1463 if (DL_FDPIC) app.loadmap = app_loadmap;
1464 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1465 if (interp_off) ldso.name = laddr(&app, interp_off);
1466 if ((aux[0] & (1UL<<AT_EXECFN))
1467 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1468 app.name = (char *)aux[AT_EXECFN];
1471 kernel_mapped_dso(&app);
1474 char *ldname = argv[0];
1475 size_t l = strlen(ldname);
1476 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1478 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1479 char *opt = argv[0]+2;
1480 *argv++ = (void *)-1;
1483 } else if (!memcmp(opt, "list", 5)) {
1485 } else if (!memcmp(opt, "library-path", 12)) {
1486 if (opt[12]=='=') env_path = opt+13;
1487 else if (opt[12]) *argv = 0;
1488 else if (*argv) env_path = *argv++;
1489 } else if (!memcmp(opt, "preload", 7)) {
1490 if (opt[7]=='=') env_preload = opt+8;
1491 else if (opt[7]) *argv = 0;
1492 else if (*argv) env_preload = *argv++;
1497 argv[-1] = (void *)(argc - (argv-argv_orig));
1499 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1501 "Dynamic Program Loader\n"
1502 "Usage: %s [options] [--] pathname%s\n",
1503 __libc_get_version(), ldname,
1504 ldd_mode ? "" : " [args]");
1507 fd = open(argv[0], O_RDONLY);
1509 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1513 Ehdr *ehdr = (void *)map_library(fd, &app);
1515 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1522 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1523 /* Find the name that would have been used for the dynamic
1524 * linker had ldd not taken its place. */
1526 for (i=0; i<app.phnum; i++) {
1527 if (app.phdr[i].p_type == PT_INTERP)
1528 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1530 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1534 libc.tls_head = tls_tail = &app.tls;
1535 app.tls_id = tls_cnt = 1;
1538 tls_offset = app.tls.size
1539 + ( -((uintptr_t)app.tls.image + app.tls.size)
1540 & (app.tls.align-1) );
1542 tls_offset = app.tls.offset = app.tls.size
1543 + ( -((uintptr_t)app.tls.image + app.tls.size)
1544 & (app.tls.align-1) );
1546 tls_align = MAXP2(tls_align, app.tls.align);
1550 makefuncdescs(&app);
1552 app.loadmap = (void *)&app_dummy_loadmap;
1553 app.loadmap->nsegs = 1;
1554 app.loadmap->segs[0].addr = (size_t)app.map;
1555 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1557 app.loadmap->segs[0].p_memsz = app.map_len;
1559 argv[-3] = (void *)app.loadmap;
1562 /* Initial dso chain consists only of the app. */
1563 head = tail = syms_tail = &app;
1565 /* Donate unused parts of app and library mapping to malloc */
1567 reclaim_gaps(&ldso);
1569 /* Load preload/needed libraries, add symbols to global namespace. */
1570 if (env_preload) load_preload(env_preload);
1572 for (struct dso *p=head; p; p=p->next)
1575 /* Attach to vdso, if provided by the kernel, last so that it does
1576 * not become part of the global namespace. */
1577 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1578 Ehdr *ehdr = (void *)vdso_base;
1579 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1580 vdso.phnum = ehdr->e_phnum;
1581 vdso.phentsize = ehdr->e_phentsize;
1582 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1583 if (phdr->p_type == PT_DYNAMIC)
1584 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1585 if (phdr->p_type == PT_LOAD)
1586 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1589 vdso.shortname = "linux-gate.so.1";
1597 for (i=0; app.dynv[i]; i+=2) {
1598 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1599 app.dynv[i+1] = (size_t)&debug;
1600 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1601 size_t *ptr = (size_t *) app.dynv[i+1];
1602 *ptr = (size_t)&debug;
1606 /* The main program must be relocated LAST since it may contin
1607 * copy relocations which depend on libraries' relocations. */
1608 reloc_all(app.next);
1612 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1613 void *initial_tls = calloc(libc.tls_size, 1);
1615 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1616 argv[0], libc.tls_size);
1619 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1623 size_t tmp_tls_size = libc.tls_size;
1624 pthread_t self = __pthread_self();
1625 /* Temporarily set the tls size to the full size of
1626 * builtin_tls so that __copy_tls will use the same layout
1627 * as it did for before. Then check, just to be safe. */
1628 libc.tls_size = sizeof builtin_tls;
1629 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1630 libc.tls_size = tmp_tls_size;
1632 static_tls_cnt = tls_cnt;
1634 if (ldso_fail) _exit(127);
1635 if (ldd_mode) _exit(0);
1637 /* Switch to runtime mode: any further failures in the dynamic
1638 * linker are a reportable failure rather than a fatal startup
1643 debug.bp = dl_debug_state;
1645 debug.base = ldso.base;
1651 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1655 void *dlopen(const char *file, int mode)
1657 struct dso *volatile p, *orig_tail, *orig_syms_tail, *next;
1658 struct tls_module *orig_tls_tail;
1659 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1664 if (!file) return head;
1666 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1667 pthread_rwlock_wrlock(&lock);
1671 orig_tls_tail = tls_tail;
1672 orig_tls_cnt = tls_cnt;
1673 orig_tls_offset = tls_offset;
1674 orig_tls_align = tls_align;
1675 orig_syms_tail = syms_tail;
1677 noload = mode & RTLD_NOLOAD;
1680 if (setjmp(*rtld_fail)) {
1681 /* Clean up anything new that was (partially) loaded */
1682 revert_syms(orig_syms_tail);
1683 for (p=orig_tail->next; p; p=next) {
1685 while (p->td_index) {
1686 void *tmp = p->td_index->next;
1691 if (p->rpath != p->rpath_orig)
1697 if (!orig_tls_tail) libc.tls_head = 0;
1698 tls_tail = orig_tls_tail;
1699 if (tls_tail) tls_tail->next = 0;
1700 tls_cnt = orig_tls_cnt;
1701 tls_offset = orig_tls_offset;
1702 tls_align = orig_tls_align;
1707 } else p = load_library(file, head);
1711 "Library %s is not already loaded" :
1712 "Error loading shared library %s: %m",
1717 /* First load handling */
1718 if (!p->relocated) {
1720 /* Make new symbols global, at least temporarily, so we can do
1721 * relocations. If not RTLD_GLOBAL, this is reverted below. */
1723 if (p->deps) for (i=0; p->deps[i]; i++)
1724 add_syms(p->deps[i]);
1728 /* If RTLD_GLOBAL was not specified, undo any new additions
1729 * to the global symbol table. This is a nop if the library was
1730 * previously loaded and already global. */
1731 if (!(mode & RTLD_GLOBAL))
1732 revert_syms(orig_syms_tail);
1740 pthread_rwlock_unlock(&lock);
1741 if (p) do_init_fini(orig_tail);
1742 pthread_setcancelstate(cs, 0);
1746 __attribute__((__visibility__("hidden")))
1747 int __dl_invalid_handle(void *h)
1750 for (p=head; p; p=p->next) if (h==p) return 0;
1751 error("Invalid library handle %p", (void *)h);
1755 static void *addr2dso(size_t a)
1759 if (DL_FDPIC) for (p=head; p; p=p->next) {
1761 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1764 for (p=head; p; p=p->next) {
1765 if (DL_FDPIC && p->loadmap) {
1766 for (i=0; i<p->loadmap->nsegs; i++) {
1767 if (a-p->loadmap->segs[i].p_vaddr
1768 < p->loadmap->segs[i].p_memsz)
1772 if (a-(size_t)p->map < p->map_len)
1779 void *__tls_get_addr(tls_mod_off_t *);
1781 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1784 uint32_t h = 0, gh = 0, *ght;
1786 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1787 if (p == RTLD_DEFAULT) {
1789 } else if (p == RTLD_NEXT) {
1790 p = addr2dso((size_t)ra);
1794 struct symdef def = find_sym(p, s, 0);
1795 if (!def.sym) goto failed;
1796 if ((def.sym->st_info&0xf) == STT_TLS)
1797 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value});
1798 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1799 return def.dso->funcdescs + (def.sym - def.dso->syms);
1800 return laddr(def.dso, def.sym->st_value);
1802 if (__dl_invalid_handle(p))
1804 if ((ght = p->ghashtab)) {
1806 sym = gnu_lookup(gh, ght, p, s);
1809 sym = sysv_lookup(s, h, p);
1811 if (sym && (sym->st_info&0xf) == STT_TLS)
1812 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value});
1813 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1814 return p->funcdescs + (sym - p->syms);
1815 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1816 return laddr(p, sym->st_value);
1817 if (p->deps) for (i=0; p->deps[i]; i++) {
1818 if ((ght = p->deps[i]->ghashtab)) {
1819 if (!gh) gh = gnu_hash(s);
1820 sym = gnu_lookup(gh, ght, p->deps[i], s);
1822 if (!h) h = sysv_hash(s);
1823 sym = sysv_lookup(s, h, p->deps[i]);
1825 if (sym && (sym->st_info&0xf) == STT_TLS)
1826 return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value});
1827 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1828 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1829 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1830 return laddr(p->deps[i], sym->st_value);
1833 error("Symbol not found: %s", s);
1837 int dladdr(const void *addr, Dl_info *info)
1845 pthread_rwlock_rdlock(&lock);
1846 p = addr2dso((size_t)addr);
1847 pthread_rwlock_unlock(&lock);
1852 strings = p->strings;
1853 nsym = count_syms(p);
1856 size_t idx = ((size_t)addr-(size_t)p->funcdescs)
1857 / sizeof(*p->funcdescs);
1858 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1859 best = p->funcdescs + idx;
1860 bestsym = sym + idx;
1864 if (!best) for (; nsym; nsym--, sym++) {
1866 && (1<<(sym->st_info&0xf) & OK_TYPES)
1867 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1868 void *symaddr = laddr(p, sym->st_value);
1869 if (symaddr > addr || symaddr < best)
1873 if (addr == symaddr)
1878 if (!best) return 0;
1880 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
1881 best = p->funcdescs + (bestsym - p->syms);
1883 info->dli_fname = p->name;
1884 info->dli_fbase = p->base;
1885 info->dli_sname = strings + bestsym->st_name;
1886 info->dli_saddr = best;
1891 __attribute__((__visibility__("hidden")))
1892 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1895 pthread_rwlock_rdlock(&lock);
1896 res = do_dlsym(p, s, ra);
1897 pthread_rwlock_unlock(&lock);
1901 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1903 struct dso *current;
1904 struct dl_phdr_info info;
1906 for(current = head; current;) {
1907 info.dlpi_addr = (uintptr_t)current->base;
1908 info.dlpi_name = current->name;
1909 info.dlpi_phdr = current->phdr;
1910 info.dlpi_phnum = current->phnum;
1911 info.dlpi_adds = gencnt;
1913 info.dlpi_tls_modid = current->tls_id;
1914 info.dlpi_tls_data = current->tls.image;
1916 ret = (callback)(&info, sizeof (info), data);
1918 if (ret != 0) break;
1920 pthread_rwlock_rdlock(&lock);
1921 current = current->next;
1922 pthread_rwlock_unlock(&lock);
1927 __attribute__((__visibility__("hidden")))
1928 void __dl_vseterr(const char *, va_list);
1930 static void error(const char *fmt, ...)
1935 vdprintf(2, fmt, ap);
1941 __dl_vseterr(fmt, ap);