20 #include "pthread_impl.h"
24 static void error(const char *, ...);
26 #define MAXP2(a,b) (-(-(a)&-(b)))
27 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
39 struct td_index *next;
44 struct fdpic_loadmap *loadmap;
50 struct dso *next, *prev;
60 struct dso *syms_next, *lazy_next;
61 size_t *lazy, lazy_cnt;
69 struct dso **deps, *needed_by;
70 char *rpath_orig, *rpath;
71 struct tls_module tls;
73 size_t relro_start, relro_end;
75 unsigned char *new_tls;
76 volatile int new_dtv_idx, new_tls_idx;
77 struct td_index *td_index;
78 struct dso *fini_next;
83 struct fdpic_loadmap *loadmap;
98 int __init_tp(void *);
99 void __init_libc(char **, char *);
100 void *__copy_tls(unsigned char *);
102 __attribute__((__visibility__("hidden")))
103 const char *__libc_get_version(void);
105 static struct builtin_tls {
110 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
112 #define ADDEND_LIMIT 4096
113 static size_t *saved_addends, *apply_addends_to;
115 static struct dso ldso;
116 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
117 static char *env_path, *sys_path;
118 static unsigned long long gencnt;
121 static int ldso_fail;
123 static jmp_buf *rtld_fail;
124 static pthread_rwlock_t lock;
125 static struct debug debug;
126 static struct tls_module *tls_tail;
127 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
128 static size_t static_tls_cnt;
129 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
130 static struct fdpic_loadmap *app_loadmap;
131 static struct fdpic_dummy_loadmap app_dummy_loadmap;
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 = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
262 size_t ghm = 1ul << gh % (8*sizeof(size_t));
263 struct symdef def = {0};
264 for (; dso; dso=dso->syms_next) {
266 if ((ght = dso->ghashtab)) {
267 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
269 if (!h) h = sysv_hash(s);
270 sym = sysv_lookup(s, h, dso);
274 if (need_def || (sym->st_info&0xf) == STT_TLS
275 || ARCH_SYM_REJECT_UND(sym))
278 if ((sym->st_info&0xf) != STT_TLS)
280 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
281 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
289 __attribute__((__visibility__("hidden")))
290 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
292 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
294 unsigned char *base = dso->base;
295 Sym *syms = dso->syms;
296 char *strings = dso->strings;
307 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
310 /* Only ldso's REL table needs addend saving/reuse. */
311 if (rel == apply_addends_to)
316 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
317 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
318 type = R_TYPE(rel[1]);
319 if (type == REL_NONE) continue;
320 reloc_addr = laddr(dso, rel[0]);
324 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
326 } else if (reuse_addends) {
327 /* Save original addend in stage 2 where the dso
328 * chain consists of just ldso; otherwise read back
329 * saved addend since the inline one was clobbered. */
331 saved_addends[save_slot] = *reloc_addr;
332 addend = saved_addends[save_slot++];
334 addend = *reloc_addr;
337 sym_index = R_SYM(rel[1]);
339 sym = syms + sym_index;
340 name = strings + sym->st_name;
341 ctx = type==REL_COPY ? head->syms_next : head;
342 def = (sym->st_info&0xf) == STT_SECTION
343 ? (struct symdef){ .dso = dso, .sym = sym }
344 : find_sym(ctx, name, type==REL_PLT);
345 if (!def.sym && (sym->st_shndx != SHN_UNDEF
346 || sym->st_info>>4 != STB_WEAK)) {
347 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
348 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
349 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
350 dso->lazy[3*dso->lazy_cnt+2] = addend;
354 error("Error relocating %s: %s: symbol not found",
356 if (runtime) longjmp(*rtld_fail, 1);
365 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
366 tls_val = def.sym ? def.sym->st_value : 0;
372 addend -= (size_t)reloc_addr;
376 *reloc_addr = sym_val + addend;
379 *reloc_addr = (size_t)base + addend;
382 if (sym) *reloc_addr = sym_val + addend;
383 else *reloc_addr = (size_t)base + addend;
386 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
389 *(uint32_t *)reloc_addr = sym_val + addend
390 - (size_t)reloc_addr;
393 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
394 + (def.sym - def.dso->syms)) : 0;
396 case REL_FUNCDESC_VAL:
397 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
398 else *reloc_addr = sym_val;
399 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
402 *reloc_addr = def.dso->tls_id;
405 *reloc_addr = tls_val + addend - DTP_OFFSET;
409 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
413 *reloc_addr = tls_val - def.dso->tls.offset + addend;
416 *reloc_addr = def.dso->tls.offset - tls_val + addend;
420 if (stride<3) addend = reloc_addr[1];
421 if (runtime && def.dso->tls_id >= static_tls_cnt) {
422 struct td_index *new = malloc(sizeof *new);
425 "Error relocating %s: cannot allocate TLSDESC for %s",
426 dso->name, sym ? name : "(local)" );
427 longjmp(*rtld_fail, 1);
429 new->next = dso->td_index;
431 new->args[0] = def.dso->tls_id;
432 new->args[1] = tls_val + addend;
433 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
434 reloc_addr[1] = (size_t)new;
436 reloc_addr[0] = (size_t)__tlsdesc_static;
438 reloc_addr[1] = tls_val + def.dso->tls.offset
441 reloc_addr[1] = tls_val - def.dso->tls.offset
447 error("Error relocating %s: unsupported relocation type %d",
449 if (runtime) longjmp(*rtld_fail, 1);
455 static void redo_lazy_relocs()
457 struct dso *p = lazy_head, *next;
461 size_t size = p->lazy_cnt*3*sizeof(size_t);
463 do_relocs(p, p->lazy, size, 3);
465 p->lazy_next = lazy_head;
475 /* A huge hack: to make up for the wastefulness of shared libraries
476 * needing at least a page of dirty memory even if they have no global
477 * data, we reclaim the gaps at the beginning and end of writable maps
478 * and "donate" them to the heap by setting up minimal malloc
479 * structures and then freeing them. */
481 static void reclaim(struct dso *dso, size_t start, size_t end)
484 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
485 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
486 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
487 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
488 if (start>end || end-start < 4*sizeof(size_t)) return;
489 a = laddr(dso, start);
492 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
497 static void reclaim_gaps(struct dso *dso)
499 Phdr *ph = dso->phdr;
500 size_t phcnt = dso->phnum;
502 if (DL_FDPIC) return; // FIXME
503 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
504 if (ph->p_type!=PT_LOAD) continue;
505 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
506 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
507 reclaim(dso, ph->p_vaddr+ph->p_memsz,
508 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
512 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
514 static int no_map_fixed;
517 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
518 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
522 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
523 if (flags & MAP_ANONYMOUS) {
528 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
529 for (q=p; n; q+=r, off+=r, n-=r) {
531 if (r < 0 && errno != EINTR) return MAP_FAILED;
540 static void unmap_library(struct dso *dso)
544 for (i=0; i<dso->loadmap->nsegs; i++) {
545 if (!dso->loadmap->segs[i].p_memsz)
547 munmap((void *)dso->loadmap->segs[i].addr,
548 dso->loadmap->segs[i].p_memsz);
551 } else if (dso->map && dso->map_len) {
552 munmap(dso->map, dso->map_len);
556 static void *map_library(int fd, struct dso *dso)
558 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
559 void *allocated_buf=0;
561 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
562 size_t this_min, this_max;
568 unsigned char *map=MAP_FAILED, *base;
573 ssize_t l = read(fd, buf, sizeof buf);
576 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
578 phsize = eh->e_phentsize * eh->e_phnum;
579 if (phsize > sizeof buf - sizeof *eh) {
580 allocated_buf = malloc(phsize);
581 if (!allocated_buf) return 0;
582 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
583 if (l < 0) goto error;
584 if (l != phsize) goto noexec;
585 ph = ph0 = allocated_buf;
586 } else if (eh->e_phoff + phsize > l) {
587 l = pread(fd, buf+1, phsize, eh->e_phoff);
588 if (l < 0) goto error;
589 if (l != phsize) goto noexec;
590 ph = ph0 = (void *)(buf + 1);
592 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
594 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
595 if (ph->p_type == PT_DYNAMIC) {
597 } else if (ph->p_type == PT_TLS) {
598 tls_image = ph->p_vaddr;
599 dso->tls.align = ph->p_align;
600 dso->tls.len = ph->p_filesz;
601 dso->tls.size = ph->p_memsz;
602 } else if (ph->p_type == PT_GNU_RELRO) {
603 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
604 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
606 if (ph->p_type != PT_LOAD) continue;
608 if (ph->p_vaddr < addr_min) {
609 addr_min = ph->p_vaddr;
610 off_start = ph->p_offset;
611 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
612 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
613 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
615 if (ph->p_vaddr+ph->p_memsz > addr_max) {
616 addr_max = ph->p_vaddr+ph->p_memsz;
619 if (!dyn) goto noexec;
620 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
621 dso->loadmap = calloc(1, sizeof *dso->loadmap
622 + nsegs * sizeof *dso->loadmap->segs);
623 if (!dso->loadmap) goto error;
624 dso->loadmap->nsegs = nsegs;
625 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
626 if (ph->p_type != PT_LOAD) continue;
627 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
628 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
629 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
630 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
632 fd, ph->p_offset & -PAGE_SIZE);
633 if (map == MAP_FAILED) {
637 dso->loadmap->segs[i].addr = (size_t)map +
638 (ph->p_vaddr & PAGE_SIZE-1);
639 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
640 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
642 if (prot & PROT_WRITE) {
643 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
645 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
646 size_t pgend = brk + ph->p_memsz - ph->p_filesz
647 + PAGE_SIZE-1 & -PAGE_SIZE;
648 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
650 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
651 -1, off_start) == MAP_FAILED)
653 memset(map + brk, 0, pgbrk-brk);
656 map = (void *)dso->loadmap->segs[0].addr;
660 addr_max += PAGE_SIZE-1;
661 addr_max &= -PAGE_SIZE;
662 addr_min &= -PAGE_SIZE;
663 off_start &= -PAGE_SIZE;
664 map_len = addr_max - addr_min + off_start;
665 /* The first time, we map too much, possibly even more than
666 * the length of the file. This is okay because we will not
667 * use the invalid part; we just need to reserve the right
668 * amount of virtual address space to map over later. */
669 map = DL_NOMMU_SUPPORT
670 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
671 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
672 : mmap((void *)addr_min, map_len, prot,
673 MAP_PRIVATE, fd, off_start);
674 if (map==MAP_FAILED) goto error;
676 dso->map_len = map_len;
677 /* If the loaded file is not relocatable and the requested address is
678 * not available, then the load operation must fail. */
679 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
683 base = map - addr_min;
686 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
687 if (ph->p_type != PT_LOAD) continue;
688 /* Check if the programs headers are in this load segment, and
689 * if so, record the address for use by dl_iterate_phdr. */
690 if (!dso->phdr && eh->e_phoff >= ph->p_offset
691 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
692 dso->phdr = (void *)(base + ph->p_vaddr
693 + (eh->e_phoff-ph->p_offset));
694 dso->phnum = eh->e_phnum;
695 dso->phentsize = eh->e_phentsize;
697 /* Reuse the existing mapping for the lowest-address LOAD */
698 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT)
700 this_min = ph->p_vaddr & -PAGE_SIZE;
701 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
702 off_start = ph->p_offset & -PAGE_SIZE;
703 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
704 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
705 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
706 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
708 if (ph->p_memsz > ph->p_filesz) {
709 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
710 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
711 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
712 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)
716 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
717 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
718 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
725 dso->dynv = laddr(dso, dyn);
726 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
727 if (!runtime) reclaim_gaps(dso);
733 if (map!=MAP_FAILED) unmap_library(dso);
738 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
743 s += strspn(s, ":\n");
744 l = strcspn(s, ":\n");
745 if (l-1 >= INT_MAX) return -1;
746 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
747 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
755 /* Any negative value but -1 will inhibit
756 * futher path search. */
764 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
767 const char *s, *t, *origin;
769 if (p->rpath || !p->rpath_orig) return 0;
770 if (!strchr(p->rpath_orig, '$')) {
771 p->rpath = p->rpath_orig;
776 while ((t=strchr(s, '$'))) {
777 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
782 if (n > SSIZE_MAX/PATH_MAX) return 0;
784 if (p->kernel_mapped) {
785 /* $ORIGIN searches cannot be performed for the main program
786 * when it is suid/sgid/AT_SECURE. This is because the
787 * pathname is under the control of the caller of execve.
788 * For libraries, however, $ORIGIN can be processed safely
789 * since the library's pathname came from a trusted source
790 * (either system paths or a call to dlopen). */
793 l = readlink("/proc/self/exe", buf, buf_size);
794 if (l == -1) switch (errno) {
809 t = strrchr(origin, '/');
810 l = t ? t-origin : 0;
811 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
812 if (!p->rpath) return -1;
816 while ((t=strchr(s, '$'))) {
819 memcpy(d, origin, l);
821 /* It was determined previously that the '$' is followed
822 * either by "ORIGIN" or "{ORIGIN}". */
823 s = t + 7 + 2*(t[1]=='{');
829 static void decode_dyn(struct dso *p)
832 decode_vec(p->dynv, dyn, DYN_CNT);
833 p->syms = laddr(p, dyn[DT_SYMTAB]);
834 p->strings = laddr(p, dyn[DT_STRTAB]);
835 if (dyn[0]&(1<<DT_HASH))
836 p->hashtab = laddr(p, dyn[DT_HASH]);
837 if (dyn[0]&(1<<DT_RPATH))
838 p->rpath_orig = p->strings + dyn[DT_RPATH];
839 if (dyn[0]&(1<<DT_RUNPATH))
840 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
841 if (dyn[0]&(1<<DT_PLTGOT))
842 p->got = laddr(p, dyn[DT_PLTGOT]);
843 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
844 p->ghashtab = laddr(p, *dyn);
845 if (search_vec(p->dynv, dyn, DT_VERSYM))
846 p->versym = laddr(p, *dyn);
849 static size_t count_syms(struct dso *p)
851 if (p->hashtab) return p->hashtab[1];
854 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
856 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
857 if (buckets[i] > nsym)
861 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
863 while (!(*hashval++ & 1));
868 static void *dl_mmap(size_t n)
871 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
873 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
875 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
877 return p == MAP_FAILED ? 0 : p;
880 static void makefuncdescs(struct dso *p)
882 static int self_done;
883 size_t nsym = count_syms(p);
884 size_t i, size = nsym * sizeof(*p->funcdescs);
887 p->funcdescs = dl_mmap(size);
890 p->funcdescs = malloc(size);
893 if (!runtime) a_crash();
894 error("Error allocating function descriptors for %s", p->name);
895 longjmp(*rtld_fail, 1);
897 for (i=0; i<nsym; i++) {
898 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
899 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
900 p->funcdescs[i].got = p->got;
902 p->funcdescs[i].addr = 0;
903 p->funcdescs[i].got = 0;
908 static struct dso *load_library(const char *name, struct dso *needed_by)
910 char buf[2*NAME_MAX+2];
911 const char *pathname;
913 struct dso *p, temp_dso = {0};
925 /* Catch and block attempts to reload the implementation itself */
926 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
927 static const char reserved[] =
928 "c.pthread.rt.m.dl.util.xnet.";
929 const char *rp, *next;
930 for (rp=reserved; *rp; rp=next) {
931 next = strchr(rp, '.') + 1;
932 if (strncmp(name+3, rp, next-rp) == 0)
937 /* Track which names have been resolved
938 * and only report each one once. */
939 static unsigned reported;
940 unsigned mask = 1U<<(rp-reserved);
941 if (!(reported & mask)) {
943 dprintf(1, "\t%s => %s (%p)\n",
951 if (!strcmp(name, ldso.name)) is_self = 1;
960 if (strchr(name, '/')) {
962 fd = open(name, O_RDONLY|O_CLOEXEC);
964 /* Search for the name to see if it's already loaded */
965 for (p=head->next; p; p=p->next) {
966 if (p->shortname && !strcmp(p->shortname, name)) {
970 if (strlen(name) > NAME_MAX) return 0;
972 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
973 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
974 if (fixup_rpath(p, buf, sizeof buf) < 0)
975 fd = -2; /* Inhibit further search. */
977 fd = path_open(name, p->rpath, buf, sizeof buf);
983 if (ldso.name[0]=='/') {
985 for (s=t=z=ldso.name; *s; s++)
986 if (*s=='/') z=t, t=s;
987 prefix_len = z-ldso.name;
988 if (prefix_len < PATH_MAX)
995 char etc_ldso_path[prefix_len + 1
996 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
997 snprintf(etc_ldso_path, sizeof etc_ldso_path,
998 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
999 (int)prefix_len, prefix);
1000 FILE *f = fopen(etc_ldso_path, "rbe");
1002 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1007 } else if (errno != ENOENT) {
1011 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1012 fd = path_open(name, sys_path, buf, sizeof buf);
1016 if (fd < 0) return 0;
1017 if (fstat(fd, &st) < 0) {
1021 for (p=head->next; p; p=p->next) {
1022 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1023 /* If this library was previously loaded with a
1024 * pathname but a search found the same inode,
1025 * setup its shortname so it can be found by name. */
1026 if (!p->shortname && pathname != name)
1027 p->shortname = strrchr(p->name, '/')+1;
1032 map = noload ? 0 : map_library(fd, &temp_dso);
1036 /* Avoid the danger of getting two versions of libc mapped into the
1037 * same process when an absolute pathname was used. The symbols
1038 * checked are chosen to catch both musl and glibc, and to avoid
1039 * false positives from interposition-hack libraries. */
1040 decode_dyn(&temp_dso);
1041 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1042 find_sym(&temp_dso, "stdin", 1).sym) {
1043 unmap_library(&temp_dso);
1044 return load_library("libc.so", needed_by);
1047 /* Allocate storage for the new DSO. When there is TLS, this
1048 * storage must include a reservation for all pre-existing
1049 * threads to obtain copies of both the new TLS, and an
1050 * extended DTV capable of storing an additional slot for
1051 * the newly-loaded DSO. */
1052 alloc_size = sizeof *p + strlen(pathname) + 1;
1053 if (runtime && temp_dso.tls.image) {
1054 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1055 + sizeof(void *) * (tls_cnt+3);
1056 n_th = libc.threads_minus_1 + 1;
1057 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1058 else alloc_size += n_th * per_th;
1060 p = calloc(1, alloc_size);
1062 unmap_library(&temp_dso);
1065 memcpy(p, &temp_dso, sizeof temp_dso);
1068 p->needed_by = needed_by;
1070 strcpy(p->name, pathname);
1071 /* Add a shortname only if name arg was not an explicit pathname. */
1072 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1074 p->tls_id = ++tls_cnt;
1075 tls_align = MAXP2(tls_align, p->tls.align);
1077 p->tls.offset = tls_offset + ( (tls_align-1) &
1078 -(tls_offset + (uintptr_t)p->tls.image) );
1079 tls_offset += p->tls.size;
1081 tls_offset += p->tls.size + p->tls.align - 1;
1082 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1084 p->tls.offset = tls_offset;
1086 p->new_dtv = (void *)(-sizeof(size_t) &
1087 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1088 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1089 if (tls_tail) tls_tail->next = &p->tls;
1090 else libc.tls_head = &p->tls;
1098 if (DL_FDPIC) makefuncdescs(p);
1100 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1105 static void load_deps(struct dso *p)
1108 struct dso ***deps = &p->deps, **tmp, *dep;
1109 for (; p; p=p->next) {
1110 for (i=0; p->dynv[i]; i+=2) {
1111 if (p->dynv[i] != DT_NEEDED) continue;
1112 dep = load_library(p->strings + p->dynv[i+1], p);
1114 error("Error loading shared library %s: %m (needed by %s)",
1115 p->strings + p->dynv[i+1], p->name);
1116 if (runtime) longjmp(*rtld_fail, 1);
1120 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1121 if (!tmp) longjmp(*rtld_fail, 1);
1130 static void load_preload(char *s)
1134 for (z=s; *z; s=z) {
1135 for ( ; *s && (isspace(*s) || *s==':'); s++);
1136 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1144 static void add_syms(struct dso *p)
1146 if (!p->syms_next && syms_tail != p) {
1147 syms_tail->syms_next = p;
1152 static void revert_syms(struct dso *old_tail)
1154 struct dso *p, *next;
1155 /* Chop off the tail of the list of dsos that participate in
1156 * the global symbol table, reverting them to RTLD_LOCAL. */
1157 for (p=old_tail; p; p=next) {
1158 next = p->syms_next;
1161 syms_tail = old_tail;
1164 static void do_mips_relocs(struct dso *p, size_t *got)
1166 size_t i, j, rel[2];
1167 unsigned char *base = p->base;
1168 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1172 while (i--) *got++ += (size_t)base;
1174 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1175 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1176 Sym *sym = p->syms + j;
1177 rel[0] = (unsigned char *)got - base;
1178 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1179 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1180 do_relocs(p, rel, sizeof rel, 2);
1184 static void reloc_all(struct dso *p)
1186 size_t dyn[DYN_CNT];
1187 for (; p; p=p->next) {
1188 if (p->relocated) continue;
1189 decode_vec(p->dynv, dyn, DYN_CNT);
1190 if (NEED_MIPS_GOT_RELOCS)
1191 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1192 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1193 2+(dyn[DT_PLTREL]==DT_RELA));
1194 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1195 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1197 if (head != &ldso && p->relro_start != p->relro_end &&
1198 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1199 && errno != ENOSYS) {
1200 error("Error relocating %s: RELRO protection failed: %m",
1202 if (runtime) longjmp(*rtld_fail, 1);
1209 static void kernel_mapped_dso(struct dso *p)
1211 size_t min_addr = -1, max_addr = 0, cnt;
1213 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1214 if (ph->p_type == PT_DYNAMIC) {
1215 p->dynv = laddr(p, ph->p_vaddr);
1216 } else if (ph->p_type == PT_GNU_RELRO) {
1217 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1218 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1220 if (ph->p_type != PT_LOAD) continue;
1221 if (ph->p_vaddr < min_addr)
1222 min_addr = ph->p_vaddr;
1223 if (ph->p_vaddr+ph->p_memsz > max_addr)
1224 max_addr = ph->p_vaddr+ph->p_memsz;
1226 min_addr &= -PAGE_SIZE;
1227 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1228 p->map = p->base + min_addr;
1229 p->map_len = max_addr - min_addr;
1230 p->kernel_mapped = 1;
1233 void __libc_exit_fini()
1236 size_t dyn[DYN_CNT];
1237 for (p=fini_head; p; p=p->fini_next) {
1238 if (!p->constructed) continue;
1239 decode_vec(p->dynv, dyn, DYN_CNT);
1240 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1241 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1242 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1243 while (n--) ((void (*)(void))*--fn)();
1245 #ifndef NO_LEGACY_INITFINI
1246 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1247 fpaddr(p, dyn[DT_FINI])();
1252 static void do_init_fini(struct dso *p)
1254 size_t dyn[DYN_CNT];
1255 int need_locking = libc.threads_minus_1;
1256 /* Allow recursive calls that arise when a library calls
1257 * dlopen from one of its constructors, but block any
1258 * other threads until all ctors have finished. */
1259 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1260 for (; p; p=p->prev) {
1261 if (p->constructed) continue;
1263 decode_vec(p->dynv, dyn, DYN_CNT);
1264 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1265 p->fini_next = fini_head;
1268 #ifndef NO_LEGACY_INITFINI
1269 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1270 fpaddr(p, dyn[DT_INIT])();
1272 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1273 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1274 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1275 while (n--) ((void (*)(void))*fn++)();
1277 if (!need_locking && libc.threads_minus_1) {
1279 pthread_mutex_lock(&init_fini_lock);
1282 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1285 void __libc_start_init(void)
1290 static void dl_debug_state(void)
1294 weak_alias(dl_debug_state, _dl_debug_state);
1296 void __init_tls(size_t *auxv)
1300 __attribute__((__visibility__("hidden")))
1301 void *__tls_get_new(tls_mod_off_t *v)
1303 pthread_t self = __pthread_self();
1305 /* Block signals to make accessing new TLS async-signal-safe */
1307 __block_all_sigs(&set);
1308 if (v[0]<=(size_t)self->dtv[0]) {
1309 __restore_sigs(&set);
1310 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1313 /* This is safe without any locks held because, if the caller
1314 * is able to request the Nth entry of the DTV, the DSO list
1315 * must be valid at least that far out and it was synchronized
1316 * at program startup or by an already-completed call to dlopen. */
1318 for (p=head; p->tls_id != v[0]; p=p->next);
1320 /* Get new DTV space from new DSO if needed */
1321 if (v[0] > (size_t)self->dtv[0]) {
1322 void **newdtv = p->new_dtv +
1323 (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
1324 memcpy(newdtv, self->dtv,
1325 ((size_t)self->dtv[0]+1) * sizeof(void *));
1326 newdtv[0] = (void *)v[0];
1327 self->dtv = self->dtv_copy = newdtv;
1330 /* Get new TLS memory from all new DSOs up to the requested one */
1332 for (p=head; ; p=p->next) {
1333 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1334 mem = p->new_tls + (p->tls.size + p->tls.align)
1335 * a_fetch_add(&p->new_tls_idx,1);
1336 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1338 self->dtv[p->tls_id] = mem;
1339 memcpy(mem, p->tls.image, p->tls.len);
1340 if (p->tls_id == v[0]) break;
1342 __restore_sigs(&set);
1343 return mem + v[1] + DTP_OFFSET;
1346 static void update_tls_size()
1348 libc.tls_cnt = tls_cnt;
1349 libc.tls_align = tls_align;
1350 libc.tls_size = ALIGN(
1351 (1+tls_cnt) * sizeof(void *) +
1353 sizeof(struct pthread) +
1358 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1359 * following stage 2 and stage 3 functions via primitive symbolic lookup
1360 * since it does not have access to their addresses to begin with. */
1362 /* Stage 2 of the dynamic linker is called after relative relocations
1363 * have been processed. It can make function calls to static functions
1364 * and access string literals and static data, but cannot use extern
1365 * symbols. Its job is to perform symbolic relocations on the dynamic
1366 * linker itself, but some of the relocations performed may need to be
1367 * replaced later due to copy relocations in the main program. */
1369 __attribute__((__visibility__("hidden")))
1370 void __dls2(unsigned char *base, size_t *sp)
1373 void *p1 = (void *)sp[-2];
1374 void *p2 = (void *)sp[-1];
1376 size_t *auxv, aux[AUX_CNT];
1377 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1378 decode_vec(auxv, aux, AUX_CNT);
1379 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1380 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1382 app_loadmap = p2 ? p1 : 0;
1383 ldso.loadmap = p2 ? p2 : p1;
1384 ldso.base = laddr(&ldso, 0);
1388 Ehdr *ehdr = (void *)ldso.base;
1389 ldso.name = ldso.shortname = "libc.so";
1390 ldso.phnum = ehdr->e_phnum;
1391 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1392 ldso.phentsize = ehdr->e_phentsize;
1393 kernel_mapped_dso(&ldso);
1396 if (DL_FDPIC) makefuncdescs(&ldso);
1398 /* Prepare storage for to save clobbered REL addends so they
1399 * can be reused in stage 3. There should be very few. If
1400 * something goes wrong and there are a huge number, abort
1401 * instead of risking stack overflow. */
1402 size_t dyn[DYN_CNT];
1403 decode_vec(ldso.dynv, dyn, DYN_CNT);
1404 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1405 size_t rel_size = dyn[DT_RELSZ];
1406 size_t symbolic_rel_cnt = 0;
1407 apply_addends_to = rel;
1408 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1409 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1410 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1411 size_t addends[symbolic_rel_cnt+1];
1412 saved_addends = addends;
1419 /* Call dynamic linker stage-3, __dls3, looking it up
1420 * symbolically as a barrier against moving the address
1421 * load across the above relocation processing. */
1422 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1423 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1424 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1427 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1428 * fully functional. Its job is to load (if not already loaded) and
1429 * process dependencies and relocations for the main application and
1430 * transfer control to its entry point. */
1432 _Noreturn void __dls3(size_t *sp)
1434 static struct dso app, vdso;
1435 size_t aux[AUX_CNT], *auxv;
1437 char *env_preload=0;
1440 char **argv = (void *)(sp+1);
1441 char **argv_orig = argv;
1442 char **envp = argv+argc+1;
1444 /* Find aux vector just past environ[] and use it to initialize
1445 * global data that may be needed before we can make syscalls. */
1447 for (i=argc+1; argv[i]; i++);
1448 libc.auxv = auxv = (void *)(argv+i+1);
1449 decode_vec(auxv, aux, AUX_CNT);
1450 __hwcap = aux[AT_HWCAP];
1451 libc.page_size = aux[AT_PAGESZ];
1452 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1453 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1455 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1456 * use during dynamic linking. If possible it will also serve as the
1457 * thread pointer at runtime. */
1458 libc.tls_size = sizeof builtin_tls;
1459 libc.tls_align = tls_align;
1460 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1464 /* Only trust user/env if kernel says we're not suid/sgid */
1466 env_path = getenv("LD_LIBRARY_PATH");
1467 env_preload = getenv("LD_PRELOAD");
1470 /* If the main program was already loaded by the kernel,
1471 * AT_PHDR will point to some location other than the dynamic
1472 * linker's program headers. */
1473 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1474 size_t interp_off = 0;
1475 size_t tls_image = 0;
1476 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1477 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1478 app.phnum = aux[AT_PHNUM];
1479 app.phentsize = aux[AT_PHENT];
1480 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1481 if (phdr->p_type == PT_PHDR)
1482 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1483 else if (phdr->p_type == PT_INTERP)
1484 interp_off = (size_t)phdr->p_vaddr;
1485 else if (phdr->p_type == PT_TLS) {
1486 tls_image = phdr->p_vaddr;
1487 app.tls.len = phdr->p_filesz;
1488 app.tls.size = phdr->p_memsz;
1489 app.tls.align = phdr->p_align;
1492 if (DL_FDPIC) app.loadmap = app_loadmap;
1493 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1494 if (interp_off) ldso.name = laddr(&app, interp_off);
1495 if ((aux[0] & (1UL<<AT_EXECFN))
1496 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1497 app.name = (char *)aux[AT_EXECFN];
1500 kernel_mapped_dso(&app);
1503 char *ldname = argv[0];
1504 size_t l = strlen(ldname);
1505 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1507 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1508 char *opt = argv[0]+2;
1509 *argv++ = (void *)-1;
1512 } else if (!memcmp(opt, "list", 5)) {
1514 } else if (!memcmp(opt, "library-path", 12)) {
1515 if (opt[12]=='=') env_path = opt+13;
1516 else if (opt[12]) *argv = 0;
1517 else if (*argv) env_path = *argv++;
1518 } else if (!memcmp(opt, "preload", 7)) {
1519 if (opt[7]=='=') env_preload = opt+8;
1520 else if (opt[7]) *argv = 0;
1521 else if (*argv) env_preload = *argv++;
1526 argv[-1] = (void *)(argc - (argv-argv_orig));
1528 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1530 "Dynamic Program Loader\n"
1531 "Usage: %s [options] [--] pathname%s\n",
1532 __libc_get_version(), ldname,
1533 ldd_mode ? "" : " [args]");
1536 fd = open(argv[0], O_RDONLY);
1538 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1542 Ehdr *ehdr = (void *)map_library(fd, &app);
1544 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1551 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1552 /* Find the name that would have been used for the dynamic
1553 * linker had ldd not taken its place. */
1555 for (i=0; i<app.phnum; i++) {
1556 if (app.phdr[i].p_type == PT_INTERP)
1557 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1559 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1563 libc.tls_head = tls_tail = &app.tls;
1564 app.tls_id = tls_cnt = 1;
1567 tls_offset = app.tls.size
1568 + ( -((uintptr_t)app.tls.image + app.tls.size)
1569 & (app.tls.align-1) );
1571 tls_offset = app.tls.offset = app.tls.size
1572 + ( -((uintptr_t)app.tls.image + app.tls.size)
1573 & (app.tls.align-1) );
1575 tls_align = MAXP2(tls_align, app.tls.align);
1579 makefuncdescs(&app);
1581 app.loadmap = (void *)&app_dummy_loadmap;
1582 app.loadmap->nsegs = 1;
1583 app.loadmap->segs[0].addr = (size_t)app.map;
1584 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1586 app.loadmap->segs[0].p_memsz = app.map_len;
1588 argv[-3] = (void *)app.loadmap;
1591 /* Initial dso chain consists only of the app. */
1592 head = tail = syms_tail = &app;
1594 /* Donate unused parts of app and library mapping to malloc */
1596 reclaim_gaps(&ldso);
1598 /* Load preload/needed libraries, add symbols to global namespace. */
1599 if (env_preload) load_preload(env_preload);
1601 for (struct dso *p=head; p; p=p->next)
1604 /* Attach to vdso, if provided by the kernel, last so that it does
1605 * not become part of the global namespace. */
1606 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1607 Ehdr *ehdr = (void *)vdso_base;
1608 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1609 vdso.phnum = ehdr->e_phnum;
1610 vdso.phentsize = ehdr->e_phentsize;
1611 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1612 if (phdr->p_type == PT_DYNAMIC)
1613 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1614 if (phdr->p_type == PT_LOAD)
1615 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1618 vdso.shortname = "linux-gate.so.1";
1626 for (i=0; app.dynv[i]; i+=2) {
1627 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1628 app.dynv[i+1] = (size_t)&debug;
1629 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1630 size_t *ptr = (size_t *) app.dynv[i+1];
1631 *ptr = (size_t)&debug;
1635 /* The main program must be relocated LAST since it may contin
1636 * copy relocations which depend on libraries' relocations. */
1637 reloc_all(app.next);
1641 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1642 void *initial_tls = calloc(libc.tls_size, 1);
1644 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1645 argv[0], libc.tls_size);
1648 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1652 size_t tmp_tls_size = libc.tls_size;
1653 pthread_t self = __pthread_self();
1654 /* Temporarily set the tls size to the full size of
1655 * builtin_tls so that __copy_tls will use the same layout
1656 * as it did for before. Then check, just to be safe. */
1657 libc.tls_size = sizeof builtin_tls;
1658 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1659 libc.tls_size = tmp_tls_size;
1661 static_tls_cnt = tls_cnt;
1663 if (ldso_fail) _exit(127);
1664 if (ldd_mode) _exit(0);
1666 /* Switch to runtime mode: any further failures in the dynamic
1667 * linker are a reportable failure rather than a fatal startup
1672 debug.bp = dl_debug_state;
1674 debug.base = ldso.base;
1680 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1684 static void prepare_lazy(struct dso *p)
1686 size_t dyn[DYN_CNT], n, flags1=0;
1687 decode_vec(p->dynv, dyn, DYN_CNT);
1688 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1689 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1691 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1692 if (NEED_MIPS_GOT_RELOCS) {
1693 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1694 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1697 p->lazy = calloc(n, 3*sizeof(size_t));
1699 error("Error preparing lazy relocation for %s: %m", p->name);
1700 longjmp(*rtld_fail, 1);
1702 p->lazy_next = lazy_head;
1706 void *dlopen(const char *file, int mode)
1708 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1709 struct tls_module *orig_tls_tail;
1710 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1715 if (!file) return head;
1717 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1718 pthread_rwlock_wrlock(&lock);
1722 orig_tls_tail = tls_tail;
1723 orig_tls_cnt = tls_cnt;
1724 orig_tls_offset = tls_offset;
1725 orig_tls_align = tls_align;
1726 orig_lazy_head = lazy_head;
1727 orig_syms_tail = syms_tail;
1729 noload = mode & RTLD_NOLOAD;
1732 if (setjmp(*rtld_fail)) {
1733 /* Clean up anything new that was (partially) loaded */
1734 revert_syms(orig_syms_tail);
1735 for (p=orig_tail->next; p; p=next) {
1737 while (p->td_index) {
1738 void *tmp = p->td_index->next;
1743 if (p->rpath != p->rpath_orig)
1749 if (!orig_tls_tail) libc.tls_head = 0;
1750 tls_tail = orig_tls_tail;
1751 if (tls_tail) tls_tail->next = 0;
1752 tls_cnt = orig_tls_cnt;
1753 tls_offset = orig_tls_offset;
1754 tls_align = orig_tls_align;
1755 lazy_head = orig_lazy_head;
1760 } else p = load_library(file, head);
1764 "Library %s is not already loaded" :
1765 "Error loading shared library %s: %m",
1770 /* First load handling */
1773 if (!p->relocated && (mode & RTLD_LAZY)) {
1775 if (p->deps) for (i=0; p->deps[i]; i++)
1776 if (!p->deps[i]->relocated)
1777 prepare_lazy(p->deps[i]);
1779 /* Make new symbols global, at least temporarily, so we can do
1780 * relocations. If not RTLD_GLOBAL, this is reverted below. */
1782 if (p->deps) for (i=0; p->deps[i]; i++)
1783 add_syms(p->deps[i]);
1787 /* If RTLD_GLOBAL was not specified, undo any new additions
1788 * to the global symbol table. This is a nop if the library was
1789 * previously loaded and already global. */
1790 if (!(mode & RTLD_GLOBAL))
1791 revert_syms(orig_syms_tail);
1793 /* Processing of deferred lazy relocations must not happen until
1794 * the new libraries are committed; otherwise we could end up with
1795 * relocations resolved to symbol definitions that get removed. */
1804 pthread_rwlock_unlock(&lock);
1805 if (p) do_init_fini(orig_tail);
1806 pthread_setcancelstate(cs, 0);
1810 __attribute__((__visibility__("hidden")))
1811 int __dl_invalid_handle(void *h)
1814 for (p=head; p; p=p->next) if (h==p) return 0;
1815 error("Invalid library handle %p", (void *)h);
1819 static void *addr2dso(size_t a)
1823 if (DL_FDPIC) for (p=head; p; p=p->next) {
1825 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1828 for (p=head; p; p=p->next) {
1829 if (DL_FDPIC && p->loadmap) {
1830 for (i=0; i<p->loadmap->nsegs; i++) {
1831 if (a-p->loadmap->segs[i].p_vaddr
1832 < p->loadmap->segs[i].p_memsz)
1836 if (a-(size_t)p->map < p->map_len)
1843 void *__tls_get_addr(tls_mod_off_t *);
1845 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1848 uint32_t h = 0, gh = 0, *ght;
1850 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1851 if (p == RTLD_DEFAULT) {
1853 } else if (p == RTLD_NEXT) {
1854 p = addr2dso((size_t)ra);
1858 struct symdef def = find_sym(p, s, 0);
1859 if (!def.sym) goto failed;
1860 if ((def.sym->st_info&0xf) == STT_TLS)
1861 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value});
1862 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1863 return def.dso->funcdescs + (def.sym - def.dso->syms);
1864 return laddr(def.dso, def.sym->st_value);
1866 if (__dl_invalid_handle(p))
1868 if ((ght = p->ghashtab)) {
1870 sym = gnu_lookup(gh, ght, p, s);
1873 sym = sysv_lookup(s, h, p);
1875 if (sym && (sym->st_info&0xf) == STT_TLS)
1876 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value});
1877 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1878 return p->funcdescs + (sym - p->syms);
1879 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1880 return laddr(p, sym->st_value);
1881 if (p->deps) for (i=0; p->deps[i]; i++) {
1882 if ((ght = p->deps[i]->ghashtab)) {
1883 if (!gh) gh = gnu_hash(s);
1884 sym = gnu_lookup(gh, ght, p->deps[i], s);
1886 if (!h) h = sysv_hash(s);
1887 sym = sysv_lookup(s, h, p->deps[i]);
1889 if (sym && (sym->st_info&0xf) == STT_TLS)
1890 return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value});
1891 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1892 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1893 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1894 return laddr(p->deps[i], sym->st_value);
1897 error("Symbol not found: %s", s);
1901 int dladdr(const void *addr, Dl_info *info)
1909 pthread_rwlock_rdlock(&lock);
1910 p = addr2dso((size_t)addr);
1911 pthread_rwlock_unlock(&lock);
1916 strings = p->strings;
1917 nsym = count_syms(p);
1920 size_t idx = ((size_t)addr-(size_t)p->funcdescs)
1921 / sizeof(*p->funcdescs);
1922 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1923 best = p->funcdescs + idx;
1924 bestsym = sym + idx;
1928 if (!best) for (; nsym; nsym--, sym++) {
1930 && (1<<(sym->st_info&0xf) & OK_TYPES)
1931 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1932 void *symaddr = laddr(p, sym->st_value);
1933 if (symaddr > addr || symaddr < best)
1937 if (addr == symaddr)
1942 if (!best) return 0;
1944 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
1945 best = p->funcdescs + (bestsym - p->syms);
1947 info->dli_fname = p->name;
1948 info->dli_fbase = p->base;
1949 info->dli_sname = strings + bestsym->st_name;
1950 info->dli_saddr = best;
1955 __attribute__((__visibility__("hidden")))
1956 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1959 pthread_rwlock_rdlock(&lock);
1960 res = do_dlsym(p, s, ra);
1961 pthread_rwlock_unlock(&lock);
1965 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1967 struct dso *current;
1968 struct dl_phdr_info info;
1970 for(current = head; current;) {
1971 info.dlpi_addr = (uintptr_t)current->base;
1972 info.dlpi_name = current->name;
1973 info.dlpi_phdr = current->phdr;
1974 info.dlpi_phnum = current->phnum;
1975 info.dlpi_adds = gencnt;
1977 info.dlpi_tls_modid = current->tls_id;
1978 info.dlpi_tls_data = current->tls.image;
1980 ret = (callback)(&info, sizeof (info), data);
1982 if (ret != 0) break;
1984 pthread_rwlock_rdlock(&lock);
1985 current = current->next;
1986 pthread_rwlock_unlock(&lock);
1991 __attribute__((__visibility__("hidden")))
1992 void __dl_vseterr(const char *, va_list);
1994 static void error(const char *fmt, ...)
1999 vdprintf(2, fmt, ap);
2005 __dl_vseterr(fmt, ap);