20 #include "pthread_impl.h"
24 static void error(const char *, ...);
28 #define MAXP2(a,b) (-(-(a)&-(b)))
29 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
41 struct td_index *next;
46 struct fdpic_loadmap *loadmap;
52 struct dso *next, *prev;
71 struct dso **deps, *needed_by;
72 char *rpath_orig, *rpath;
74 size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
75 size_t relro_start, relro_end;
77 unsigned char *new_tls;
78 volatile int new_dtv_idx, new_tls_idx;
79 struct td_index *td_index;
80 struct dso *fini_next;
85 struct fdpic_loadmap *loadmap;
100 int __init_tp(void *);
101 void __init_libc(char **, char *);
103 const char *__libc_get_version(void);
105 static struct builtin_tls {
110 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
112 #define ADDEND_LIMIT 4096
113 static size_t *saved_addends, *apply_addends_to;
115 static struct dso ldso;
116 static struct dso *head, *tail, *fini_head;
117 static char *env_path, *sys_path;
118 static unsigned long long gencnt;
121 static int ldso_fail;
123 static jmp_buf *rtld_fail;
124 static pthread_rwlock_t lock;
125 static struct debug debug;
126 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
127 static size_t static_tls_cnt;
128 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
129 static struct fdpic_loadmap *app_loadmap;
130 static struct fdpic_dummy_loadmap app_dummy_loadmap;
132 struct debug *_dl_debug_addr = &debug;
134 static int dl_strcmp(const char *l, const char *r)
136 for (; *l==*r && *l; l++, r++);
137 return *(unsigned char *)l - *(unsigned char *)r;
139 #define strcmp(l,r) dl_strcmp(l,r)
141 /* Compute load address for a virtual address in a given dso. */
143 static void *laddr(const struct dso *p, size_t v)
146 if (!p->loadmap) return p->base + v;
147 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
148 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
150 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
151 laddr(p, v), (p)->got })
153 #define laddr(p, v) (void *)((p)->base + (v))
154 #define fpaddr(p, v) ((void (*)())laddr(p, v))
157 static void decode_vec(size_t *v, size_t *a, size_t cnt)
160 for (i=0; i<cnt; i++) a[i] = 0;
161 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
167 static int search_vec(size_t *v, size_t *r, size_t key)
169 for (; v[0]!=key; v+=2)
175 static uint32_t sysv_hash(const char *s0)
177 const unsigned char *s = (void *)s0;
183 return h & 0xfffffff;
186 static uint32_t gnu_hash(const char *s0)
188 const unsigned char *s = (void *)s0;
189 uint_fast32_t h = 5381;
195 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
198 Sym *syms = dso->syms;
199 uint32_t *hashtab = dso->hashtab;
200 char *strings = dso->strings;
201 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
202 if ((!dso->versym || dso->versym[i] >= 0)
203 && (!strcmp(s, strings+syms[i].st_name)))
209 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
211 uint32_t nbuckets = hashtab[0];
212 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
213 uint32_t i = buckets[h1 % nbuckets];
217 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
219 for (h1 |= 1; ; i++) {
220 uint32_t h2 = *hashval++;
221 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
222 && !strcmp(s, dso->strings + dso->syms[i].st_name))
230 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
232 const size_t *bloomwords = (const void *)(hashtab+4);
233 size_t f = bloomwords[fofs & (hashtab[2]-1)];
234 if (!(f & fmask)) return 0;
236 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
237 if (!(f & 1)) return 0;
239 return gnu_lookup(h1, hashtab, dso, s);
242 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
243 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
245 #ifndef ARCH_SYM_REJECT_UND
246 #define ARCH_SYM_REJECT_UND(s) 0
249 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
251 uint32_t h = 0, gh, gho, *ght;
253 struct symdef def = {0};
254 for (; dso; dso=dso->next) {
256 if (!dso->global) continue;
257 if ((ght = dso->ghashtab)) {
260 int maskbits = 8 * sizeof ghm;
262 ghm = 1ul << gh % maskbits;
264 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
266 if (!h) h = sysv_hash(s);
267 sym = sysv_lookup(s, h, dso);
271 if (need_def || (sym->st_info&0xf) == STT_TLS
272 || ARCH_SYM_REJECT_UND(sym))
275 if ((sym->st_info&0xf) != STT_TLS)
277 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
278 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
280 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
283 if (sym->st_info>>4 == STB_GLOBAL) break;
288 __attribute__((__visibility__("hidden")))
289 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
291 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
293 unsigned char *base = dso->base;
294 Sym *syms = dso->syms;
295 char *strings = dso->strings;
306 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
309 /* Only ldso's REL table needs addend saving/reuse. */
310 if (rel == apply_addends_to)
315 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
316 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
317 type = R_TYPE(rel[1]);
318 if (type == REL_NONE) continue;
319 sym_index = R_SYM(rel[1]);
320 reloc_addr = laddr(dso, rel[0]);
322 sym = syms + sym_index;
323 name = strings + sym->st_name;
324 ctx = type==REL_COPY ? head->next : head;
325 def = (sym->st_info&0xf) == STT_SECTION
326 ? (struct symdef){ .dso = dso, .sym = sym }
327 : find_sym(ctx, name, type==REL_PLT);
328 if (!def.sym && (sym->st_shndx != SHN_UNDEF
329 || sym->st_info>>4 != STB_WEAK)) {
330 error("Error relocating %s: %s: symbol not found",
332 if (runtime) longjmp(*rtld_fail, 1);
343 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
345 } else if (reuse_addends) {
346 /* Save original addend in stage 2 where the dso
347 * chain consists of just ldso; otherwise read back
348 * saved addend since the inline one was clobbered. */
350 saved_addends[save_slot] = *reloc_addr;
351 addend = saved_addends[save_slot++];
353 addend = *reloc_addr;
356 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
357 tls_val = def.sym ? def.sym->st_value : 0;
363 addend -= (size_t)reloc_addr;
367 *reloc_addr = sym_val + addend;
370 *reloc_addr = (size_t)base + addend;
373 if (sym) *reloc_addr = sym_val + addend;
374 else *reloc_addr = (size_t)base + addend;
377 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
380 *(uint32_t *)reloc_addr = sym_val + addend
381 - (size_t)reloc_addr;
384 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
385 + (def.sym - def.dso->syms)) : 0;
387 case REL_FUNCDESC_VAL:
388 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
389 else *reloc_addr = sym_val;
390 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
393 *reloc_addr = def.dso->tls_id;
396 *reloc_addr = tls_val + addend - DTP_OFFSET;
400 *reloc_addr = tls_val + def.dso->tls_offset + TPOFF_K + addend;
404 *reloc_addr = tls_val - def.dso->tls_offset + addend;
407 *reloc_addr = def.dso->tls_offset - tls_val + addend;
411 if (stride<3) addend = reloc_addr[1];
412 if (runtime && def.dso->tls_id >= static_tls_cnt) {
413 struct td_index *new = malloc(sizeof *new);
416 "Error relocating %s: cannot allocate TLSDESC for %s",
417 dso->name, sym ? name : "(local)" );
418 longjmp(*rtld_fail, 1);
420 new->next = dso->td_index;
422 new->args[0] = def.dso->tls_id;
423 new->args[1] = tls_val + addend;
424 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
425 reloc_addr[1] = (size_t)new;
427 reloc_addr[0] = (size_t)__tlsdesc_static;
429 reloc_addr[1] = tls_val + def.dso->tls_offset
432 reloc_addr[1] = tls_val - def.dso->tls_offset
438 error("Error relocating %s: unsupported relocation type %d",
440 if (runtime) longjmp(*rtld_fail, 1);
446 /* A huge hack: to make up for the wastefulness of shared libraries
447 * needing at least a page of dirty memory even if they have no global
448 * data, we reclaim the gaps at the beginning and end of writable maps
449 * and "donate" them to the heap by setting up minimal malloc
450 * structures and then freeing them. */
452 static void reclaim(struct dso *dso, size_t start, size_t end)
455 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
456 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
457 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
458 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
459 if (start>end || end-start < 4*sizeof(size_t)) return;
460 a = laddr(dso, start);
463 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
468 static void reclaim_gaps(struct dso *dso)
470 Phdr *ph = dso->phdr;
471 size_t phcnt = dso->phnum;
473 if (DL_FDPIC) return; // FIXME
474 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
475 if (ph->p_type!=PT_LOAD) continue;
476 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
477 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
478 reclaim(dso, ph->p_vaddr+ph->p_memsz,
479 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
483 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
485 static int no_map_fixed;
488 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
489 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
493 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
494 if (flags & MAP_ANONYMOUS) {
499 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
500 for (q=p; n; q+=r, off+=r, n-=r) {
502 if (r < 0 && errno != EINTR) return MAP_FAILED;
511 static void unmap_library(struct dso *dso)
515 for (i=0; i<dso->loadmap->nsegs; i++) {
516 if (!dso->loadmap->segs[i].p_memsz)
518 munmap((void *)dso->loadmap->segs[i].addr,
519 dso->loadmap->segs[i].p_memsz);
522 } else if (dso->map && dso->map_len) {
523 munmap(dso->map, dso->map_len);
527 static void *map_library(int fd, struct dso *dso)
529 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
530 void *allocated_buf=0;
532 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
533 size_t this_min, this_max;
539 unsigned char *map=MAP_FAILED, *base;
544 ssize_t l = read(fd, buf, sizeof buf);
547 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
549 phsize = eh->e_phentsize * eh->e_phnum;
550 if (phsize > sizeof buf - sizeof *eh) {
551 allocated_buf = malloc(phsize);
552 if (!allocated_buf) return 0;
553 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
554 if (l < 0) goto error;
555 if (l != phsize) goto noexec;
556 ph = ph0 = allocated_buf;
557 } else if (eh->e_phoff + phsize > l) {
558 l = pread(fd, buf+1, phsize, eh->e_phoff);
559 if (l < 0) goto error;
560 if (l != phsize) goto noexec;
561 ph = ph0 = (void *)(buf + 1);
563 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
565 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
566 if (ph->p_type == PT_DYNAMIC) {
568 } else if (ph->p_type == PT_TLS) {
569 tls_image = ph->p_vaddr;
570 dso->tls_align = ph->p_align;
571 dso->tls_len = ph->p_filesz;
572 dso->tls_size = ph->p_memsz;
573 } else if (ph->p_type == PT_GNU_RELRO) {
574 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
575 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
577 if (ph->p_type != PT_LOAD) continue;
579 if (ph->p_vaddr < addr_min) {
580 addr_min = ph->p_vaddr;
581 off_start = ph->p_offset;
582 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
583 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
584 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
586 if (ph->p_vaddr+ph->p_memsz > addr_max) {
587 addr_max = ph->p_vaddr+ph->p_memsz;
590 if (!dyn) goto noexec;
591 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
592 dso->loadmap = calloc(1, sizeof *dso->loadmap
593 + nsegs * sizeof *dso->loadmap->segs);
594 if (!dso->loadmap) goto error;
595 dso->loadmap->nsegs = nsegs;
596 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
597 if (ph->p_type != PT_LOAD) continue;
598 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
599 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
600 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
601 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
602 prot, (prot&PROT_WRITE) ? MAP_PRIVATE : MAP_SHARED,
603 fd, ph->p_offset & -PAGE_SIZE);
604 if (map == MAP_FAILED) {
608 dso->loadmap->segs[i].addr = (size_t)map +
609 (ph->p_vaddr & PAGE_SIZE-1);
610 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
611 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
613 if (prot & PROT_WRITE) {
614 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
616 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
617 size_t pgend = brk + ph->p_memsz - ph->p_filesz
618 + PAGE_SIZE-1 & -PAGE_SIZE;
619 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
621 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
622 -1, off_start) == MAP_FAILED)
624 memset(map + brk, 0, pgbrk-brk);
627 map = (void *)dso->loadmap->segs[0].addr;
631 addr_max += PAGE_SIZE-1;
632 addr_max &= -PAGE_SIZE;
633 addr_min &= -PAGE_SIZE;
634 off_start &= -PAGE_SIZE;
635 map_len = addr_max - addr_min + off_start;
636 /* The first time, we map too much, possibly even more than
637 * the length of the file. This is okay because we will not
638 * use the invalid part; we just need to reserve the right
639 * amount of virtual address space to map over later. */
640 map = DL_NOMMU_SUPPORT
641 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
642 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
643 : mmap((void *)addr_min, map_len, prot,
644 MAP_PRIVATE, fd, off_start);
645 if (map==MAP_FAILED) goto error;
647 dso->map_len = map_len;
648 /* If the loaded file is not relocatable and the requested address is
649 * not available, then the load operation must fail. */
650 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
654 base = map - addr_min;
657 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
658 if (ph->p_type != PT_LOAD) continue;
659 /* Check if the programs headers are in this load segment, and
660 * if so, record the address for use by dl_iterate_phdr. */
661 if (!dso->phdr && eh->e_phoff >= ph->p_offset
662 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
663 dso->phdr = (void *)(base + ph->p_vaddr
664 + (eh->e_phoff-ph->p_offset));
665 dso->phnum = eh->e_phnum;
666 dso->phentsize = eh->e_phentsize;
668 /* Reuse the existing mapping for the lowest-address LOAD */
669 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT)
671 this_min = ph->p_vaddr & -PAGE_SIZE;
672 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
673 off_start = ph->p_offset & -PAGE_SIZE;
674 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
675 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
676 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
677 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
679 if (ph->p_memsz > ph->p_filesz) {
680 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
681 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
682 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
683 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)
687 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
688 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
689 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
696 dso->dynv = laddr(dso, dyn);
697 if (dso->tls_size) dso->tls_image = laddr(dso, tls_image);
698 if (!runtime) reclaim_gaps(dso);
704 if (map!=MAP_FAILED) unmap_library(dso);
709 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
714 s += strspn(s, ":\n");
715 l = strcspn(s, ":\n");
716 if (l-1 >= INT_MAX) return -1;
717 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
718 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
726 /* Any negative value but -1 will inhibit
727 * futher path search. */
735 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
738 const char *s, *t, *origin;
740 if (p->rpath || !p->rpath_orig) return 0;
741 if (!strchr(p->rpath_orig, '$')) {
742 p->rpath = p->rpath_orig;
747 while ((t=strchr(s, '$'))) {
748 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
753 if (n > SSIZE_MAX/PATH_MAX) return 0;
755 if (p->kernel_mapped) {
756 /* $ORIGIN searches cannot be performed for the main program
757 * when it is suid/sgid/AT_SECURE. This is because the
758 * pathname is under the control of the caller of execve.
759 * For libraries, however, $ORIGIN can be processed safely
760 * since the library's pathname came from a trusted source
761 * (either system paths or a call to dlopen). */
764 l = readlink("/proc/self/exe", buf, buf_size);
765 if (l == -1) switch (errno) {
780 t = strrchr(origin, '/');
781 l = t ? t-origin : 0;
782 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
783 if (!p->rpath) return -1;
787 while ((t=strchr(s, '$'))) {
790 memcpy(d, origin, l);
792 /* It was determined previously that the '$' is followed
793 * either by "ORIGIN" or "{ORIGIN}". */
794 s = t + 7 + 2*(t[1]=='{');
800 static void decode_dyn(struct dso *p)
803 decode_vec(p->dynv, dyn, DYN_CNT);
804 p->syms = laddr(p, dyn[DT_SYMTAB]);
805 p->strings = laddr(p, dyn[DT_STRTAB]);
806 if (dyn[0]&(1<<DT_HASH))
807 p->hashtab = laddr(p, dyn[DT_HASH]);
808 if (dyn[0]&(1<<DT_RPATH))
809 p->rpath_orig = p->strings + dyn[DT_RPATH];
810 if (dyn[0]&(1<<DT_RUNPATH))
811 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
812 if (dyn[0]&(1<<DT_PLTGOT))
813 p->got = laddr(p, dyn[DT_PLTGOT]);
814 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
815 p->ghashtab = laddr(p, *dyn);
816 if (search_vec(p->dynv, dyn, DT_VERSYM))
817 p->versym = laddr(p, *dyn);
820 static size_t count_syms(struct dso *p)
822 if (p->hashtab) return p->hashtab[1];
825 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
827 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
828 if (buckets[i] > nsym)
832 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
834 while (!(*hashval++ & 1));
839 static void *dl_mmap(size_t n)
842 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
844 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
846 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
848 return p == MAP_FAILED ? 0 : p;
851 static void makefuncdescs(struct dso *p)
853 static int self_done;
854 size_t nsym = count_syms(p);
855 size_t i, size = nsym * sizeof(*p->funcdescs);
858 p->funcdescs = dl_mmap(size);
861 p->funcdescs = malloc(size);
864 if (!runtime) a_crash();
865 error("Error allocating function descriptors for %s", p->name);
866 longjmp(*rtld_fail, 1);
868 for (i=0; i<nsym; i++) {
869 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
870 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
871 p->funcdescs[i].got = p->got;
873 p->funcdescs[i].addr = 0;
874 p->funcdescs[i].got = 0;
879 static struct dso *load_library(const char *name, struct dso *needed_by)
881 char buf[2*NAME_MAX+2];
882 const char *pathname;
884 struct dso *p, temp_dso = {0};
896 /* Catch and block attempts to reload the implementation itself */
897 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
898 static const char *rp, reserved[] =
899 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
900 char *z = strchr(name, '.');
903 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
906 /* Track which names have been resolved
907 * and only report each one once. */
908 static unsigned reported;
909 unsigned mask = 1U<<(rp-reserved);
910 if (!(reported & mask)) {
912 dprintf(1, "\t%s => %s (%p)\n",
921 if (!strcmp(name, ldso.name)) is_self = 1;
926 tail = ldso.next ? ldso.next : &ldso;
930 if (strchr(name, '/')) {
932 fd = open(name, O_RDONLY|O_CLOEXEC);
934 /* Search for the name to see if it's already loaded */
935 for (p=head->next; p; p=p->next) {
936 if (p->shortname && !strcmp(p->shortname, name)) {
941 if (strlen(name) > NAME_MAX) return 0;
943 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
944 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
945 if (fixup_rpath(p, buf, sizeof buf) < 0)
946 fd = -2; /* Inhibit further search. */
948 fd = path_open(name, p->rpath, buf, sizeof buf);
954 if (ldso.name[0]=='/') {
956 for (s=t=z=ldso.name; *s; s++)
957 if (*s=='/') z=t, t=s;
958 prefix_len = z-ldso.name;
959 if (prefix_len < PATH_MAX)
966 char etc_ldso_path[prefix_len + 1
967 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
968 snprintf(etc_ldso_path, sizeof etc_ldso_path,
969 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
970 (int)prefix_len, prefix);
971 FILE *f = fopen(etc_ldso_path, "rbe");
973 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
978 } else if (errno != ENOENT) {
982 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
983 fd = path_open(name, sys_path, buf, sizeof buf);
987 if (fd < 0) return 0;
988 if (fstat(fd, &st) < 0) {
992 for (p=head->next; p; p=p->next) {
993 if (p->dev == st.st_dev && p->ino == st.st_ino) {
994 /* If this library was previously loaded with a
995 * pathname but a search found the same inode,
996 * setup its shortname so it can be found by name. */
997 if (!p->shortname && pathname != name)
998 p->shortname = strrchr(p->name, '/')+1;
1004 map = noload ? 0 : map_library(fd, &temp_dso);
1008 /* Allocate storage for the new DSO. When there is TLS, this
1009 * storage must include a reservation for all pre-existing
1010 * threads to obtain copies of both the new TLS, and an
1011 * extended DTV capable of storing an additional slot for
1012 * the newly-loaded DSO. */
1013 alloc_size = sizeof *p + strlen(pathname) + 1;
1014 if (runtime && temp_dso.tls_image) {
1015 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
1016 + sizeof(void *) * (tls_cnt+3);
1017 n_th = libc.threads_minus_1 + 1;
1018 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1019 else alloc_size += n_th * per_th;
1021 p = calloc(1, alloc_size);
1023 unmap_library(&temp_dso);
1026 memcpy(p, &temp_dso, sizeof temp_dso);
1031 p->needed_by = needed_by;
1033 strcpy(p->name, pathname);
1034 /* Add a shortname only if name arg was not an explicit pathname. */
1035 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1037 p->tls_id = ++tls_cnt;
1038 tls_align = MAXP2(tls_align, p->tls_align);
1040 p->tls_offset = tls_offset + ( (tls_align-1) &
1041 -(tls_offset + (uintptr_t)p->tls_image) );
1042 tls_offset += p->tls_size;
1044 tls_offset += p->tls_size + p->tls_align - 1;
1045 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
1047 p->tls_offset = tls_offset;
1049 p->new_dtv = (void *)(-sizeof(size_t) &
1050 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1051 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1058 if (DL_FDPIC) makefuncdescs(p);
1060 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1065 static void load_deps(struct dso *p)
1068 struct dso ***deps = &p->deps, **tmp, *dep;
1069 for (; p; p=p->next) {
1070 for (i=0; p->dynv[i]; i+=2) {
1071 if (p->dynv[i] != DT_NEEDED) continue;
1072 dep = load_library(p->strings + p->dynv[i+1], p);
1074 error("Error loading shared library %s: %m (needed by %s)",
1075 p->strings + p->dynv[i+1], p->name);
1076 if (runtime) longjmp(*rtld_fail, 1);
1080 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1081 if (!tmp) longjmp(*rtld_fail, 1);
1090 static void load_preload(char *s)
1094 for (z=s; *z; s=z) {
1095 for ( ; *s && (isspace(*s) || *s==':'); s++);
1096 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1104 static void make_global(struct dso *p)
1106 for (; p; p=p->next) p->global = 1;
1109 static void do_mips_relocs(struct dso *p, size_t *got)
1111 size_t i, j, rel[2];
1112 unsigned char *base = p->base;
1113 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1117 while (i--) *got++ += (size_t)base;
1119 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1120 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1121 Sym *sym = p->syms + j;
1122 rel[0] = (unsigned char *)got - base;
1123 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1124 rel[1] = sym-p->syms << 8 | R_MIPS_JUMP_SLOT;
1125 do_relocs(p, rel, sizeof rel, 2);
1129 static void reloc_all(struct dso *p)
1131 size_t dyn[DYN_CNT];
1132 for (; p; p=p->next) {
1133 if (p->relocated) continue;
1134 decode_vec(p->dynv, dyn, DYN_CNT);
1135 if (NEED_MIPS_GOT_RELOCS)
1136 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1137 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1138 2+(dyn[DT_PLTREL]==DT_RELA));
1139 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1140 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1142 if (head != &ldso && p->relro_start != p->relro_end &&
1143 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1144 && errno != ENOSYS) {
1145 error("Error relocating %s: RELRO protection failed: %m",
1147 if (runtime) longjmp(*rtld_fail, 1);
1154 static void kernel_mapped_dso(struct dso *p)
1156 size_t min_addr = -1, max_addr = 0, cnt;
1158 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1159 if (ph->p_type == PT_DYNAMIC) {
1160 p->dynv = laddr(p, ph->p_vaddr);
1161 } else if (ph->p_type == PT_GNU_RELRO) {
1162 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1163 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1165 if (ph->p_type != PT_LOAD) continue;
1166 if (ph->p_vaddr < min_addr)
1167 min_addr = ph->p_vaddr;
1168 if (ph->p_vaddr+ph->p_memsz > max_addr)
1169 max_addr = ph->p_vaddr+ph->p_memsz;
1171 min_addr &= -PAGE_SIZE;
1172 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1173 p->map = p->base + min_addr;
1174 p->map_len = max_addr - min_addr;
1175 p->kernel_mapped = 1;
1178 static void do_fini()
1181 size_t dyn[DYN_CNT];
1182 for (p=fini_head; p; p=p->fini_next) {
1183 if (!p->constructed) continue;
1184 decode_vec(p->dynv, dyn, DYN_CNT);
1185 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1186 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1187 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1188 while (n--) ((void (*)(void))*--fn)();
1190 #ifndef NO_LEGACY_INITFINI
1191 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1192 fpaddr(p, dyn[DT_FINI])();
1197 static void do_init_fini(struct dso *p)
1199 size_t dyn[DYN_CNT];
1200 int need_locking = libc.threads_minus_1;
1201 /* Allow recursive calls that arise when a library calls
1202 * dlopen from one of its constructors, but block any
1203 * other threads until all ctors have finished. */
1204 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1205 for (; p; p=p->prev) {
1206 if (p->constructed) continue;
1208 decode_vec(p->dynv, dyn, DYN_CNT);
1209 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1210 p->fini_next = fini_head;
1213 #ifndef NO_LEGACY_INITFINI
1214 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1215 fpaddr(p, dyn[DT_INIT])();
1217 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1218 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1219 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1220 while (n--) ((void (*)(void))*fn++)();
1222 if (!need_locking && libc.threads_minus_1) {
1224 pthread_mutex_lock(&init_fini_lock);
1227 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1230 void __libc_start_init(void)
1235 static void dl_debug_state(void)
1239 weak_alias(dl_debug_state, _dl_debug_state);
1243 pthread_t self = __pthread_self();
1245 for (p=head; p; p=p->next) {
1246 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
1247 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
1248 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
1249 p->tls_size - p->tls_len);
1250 if (p->tls_id == (size_t)self->dtv[0]) break;
1254 void *__copy_tls(unsigned char *mem)
1261 dtv = (void **)(mem + libc.tls_size) - (tls_cnt + 1);
1263 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
1264 td = (pthread_t)mem;
1265 mem += sizeof(struct pthread);
1267 for (p=head; p; p=p->next) {
1268 if (!p->tls_id) continue;
1269 dtv[p->tls_id] = mem + p->tls_offset;
1270 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1275 mem += libc.tls_size - sizeof(struct pthread);
1276 mem -= (uintptr_t)mem & (tls_align-1);
1277 td = (pthread_t)mem;
1279 for (p=head; p; p=p->next) {
1280 if (!p->tls_id) continue;
1281 dtv[p->tls_id] = mem - p->tls_offset;
1282 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1285 dtv[0] = (void *)tls_cnt;
1286 td->dtv = td->dtv_copy = dtv;
1290 __attribute__((__visibility__("hidden")))
1291 void *__tls_get_new(size_t *v)
1293 pthread_t self = __pthread_self();
1295 /* Block signals to make accessing new TLS async-signal-safe */
1297 __block_all_sigs(&set);
1298 if (v[0]<=(size_t)self->dtv[0]) {
1299 __restore_sigs(&set);
1300 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1303 /* This is safe without any locks held because, if the caller
1304 * is able to request the Nth entry of the DTV, the DSO list
1305 * must be valid at least that far out and it was synchronized
1306 * at program startup or by an already-completed call to dlopen. */
1308 for (p=head; p->tls_id != v[0]; p=p->next);
1310 /* Get new DTV space from new DSO if needed */
1311 if (v[0] > (size_t)self->dtv[0]) {
1312 void **newdtv = p->new_dtv +
1313 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1314 memcpy(newdtv, self->dtv,
1315 ((size_t)self->dtv[0]+1) * sizeof(void *));
1316 newdtv[0] = (void *)v[0];
1317 self->dtv = self->dtv_copy = newdtv;
1320 /* Get new TLS memory from all new DSOs up to the requested one */
1322 for (p=head; ; p=p->next) {
1323 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1324 mem = p->new_tls + (p->tls_size + p->tls_align)
1325 * a_fetch_add(&p->new_tls_idx,1);
1326 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
1328 self->dtv[p->tls_id] = mem;
1329 memcpy(mem, p->tls_image, p->tls_len);
1330 if (p->tls_id == v[0]) break;
1332 __restore_sigs(&set);
1333 return mem + v[1] + DTP_OFFSET;
1336 static void update_tls_size()
1338 libc.tls_size = ALIGN(
1339 (1+tls_cnt) * sizeof(void *) +
1341 sizeof(struct pthread) +
1346 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1347 * following stage 2 and stage 3 functions via primitive symbolic lookup
1348 * since it does not have access to their addresses to begin with. */
1350 /* Stage 2 of the dynamic linker is called after relative relocations
1351 * have been processed. It can make function calls to static functions
1352 * and access string literals and static data, but cannot use extern
1353 * symbols. Its job is to perform symbolic relocations on the dynamic
1354 * linker itself, but some of the relocations performed may need to be
1355 * replaced later due to copy relocations in the main program. */
1357 __attribute__((__visibility__("hidden")))
1358 void __dls2(unsigned char *base, size_t *sp)
1361 void *p1 = (void *)sp[-2];
1362 void *p2 = (void *)sp[-1];
1364 size_t *auxv, aux[AUX_CNT];
1365 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1366 decode_vec(auxv, aux, AUX_CNT);
1367 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1368 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1370 app_loadmap = p2 ? p1 : 0;
1371 ldso.loadmap = p2 ? p2 : p1;
1372 ldso.base = laddr(&ldso, 0);
1376 Ehdr *ehdr = (void *)ldso.base;
1377 ldso.name = ldso.shortname = "libc.so";
1379 ldso.phnum = ehdr->e_phnum;
1380 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1381 ldso.phentsize = ehdr->e_phentsize;
1382 kernel_mapped_dso(&ldso);
1385 if (DL_FDPIC) makefuncdescs(&ldso);
1387 /* Prepare storage for to save clobbered REL addends so they
1388 * can be reused in stage 3. There should be very few. If
1389 * something goes wrong and there are a huge number, abort
1390 * instead of risking stack overflow. */
1391 size_t dyn[DYN_CNT];
1392 decode_vec(ldso.dynv, dyn, DYN_CNT);
1393 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1394 size_t rel_size = dyn[DT_RELSZ];
1395 size_t symbolic_rel_cnt = 0;
1396 apply_addends_to = rel;
1397 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1398 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1399 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1400 size_t addends[symbolic_rel_cnt+1];
1401 saved_addends = addends;
1408 /* Call dynamic linker stage-3, __dls3, looking it up
1409 * symbolically as a barrier against moving the address
1410 * load across the above relocation processing. */
1411 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1412 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1413 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1416 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1417 * fully functional. Its job is to load (if not already loaded) and
1418 * process dependencies and relocations for the main application and
1419 * transfer control to its entry point. */
1421 _Noreturn void __dls3(size_t *sp)
1423 static struct dso app, vdso;
1424 size_t aux[AUX_CNT], *auxv;
1426 char *env_preload=0;
1429 char **argv = (void *)(sp+1);
1430 char **argv_orig = argv;
1431 char **envp = argv+argc+1;
1433 /* Find aux vector just past environ[] and use it to initialize
1434 * global data that may be needed before we can make syscalls. */
1436 for (i=argc+1; argv[i]; i++);
1437 libc.auxv = auxv = (void *)(argv+i+1);
1438 decode_vec(auxv, aux, AUX_CNT);
1439 __hwcap = aux[AT_HWCAP];
1440 libc.page_size = aux[AT_PAGESZ];
1441 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1442 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1444 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1445 * use during dynamic linking. If possible it will also serve as the
1446 * thread pointer at runtime. */
1447 libc.tls_size = sizeof builtin_tls;
1448 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1452 /* Only trust user/env if kernel says we're not suid/sgid */
1454 env_path = getenv("LD_LIBRARY_PATH");
1455 env_preload = getenv("LD_PRELOAD");
1458 /* If the main program was already loaded by the kernel,
1459 * AT_PHDR will point to some location other than the dynamic
1460 * linker's program headers. */
1461 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1462 size_t interp_off = 0;
1463 size_t tls_image = 0;
1464 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1465 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1466 app.phnum = aux[AT_PHNUM];
1467 app.phentsize = aux[AT_PHENT];
1468 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1469 if (phdr->p_type == PT_PHDR)
1470 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1471 else if (phdr->p_type == PT_INTERP)
1472 interp_off = (size_t)phdr->p_vaddr;
1473 else if (phdr->p_type == PT_TLS) {
1474 tls_image = phdr->p_vaddr;
1475 app.tls_len = phdr->p_filesz;
1476 app.tls_size = phdr->p_memsz;
1477 app.tls_align = phdr->p_align;
1480 if (DL_FDPIC) app.loadmap = app_loadmap;
1481 if (app.tls_size) app.tls_image = laddr(&app, tls_image);
1482 if (interp_off) ldso.name = laddr(&app, interp_off);
1483 if ((aux[0] & (1UL<<AT_EXECFN))
1484 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1485 app.name = (char *)aux[AT_EXECFN];
1488 kernel_mapped_dso(&app);
1491 char *ldname = argv[0];
1492 size_t l = strlen(ldname);
1493 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1495 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1496 char *opt = argv[0]+2;
1497 *argv++ = (void *)-1;
1500 } else if (!memcmp(opt, "list", 5)) {
1502 } else if (!memcmp(opt, "library-path", 12)) {
1503 if (opt[12]=='=') env_path = opt+13;
1504 else if (opt[12]) *argv = 0;
1505 else if (*argv) env_path = *argv++;
1506 } else if (!memcmp(opt, "preload", 7)) {
1507 if (opt[7]=='=') env_preload = opt+8;
1508 else if (opt[7]) *argv = 0;
1509 else if (*argv) env_preload = *argv++;
1514 argv[-1] = (void *)(argc - (argv-argv_orig));
1516 dprintf(2, "musl libc\n"
1518 "Dynamic Program Loader\n"
1519 "Usage: %s [options] [--] pathname%s\n",
1520 __libc_get_version(), ldname,
1521 ldd_mode ? "" : " [args]");
1524 fd = open(argv[0], O_RDONLY);
1526 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1530 Ehdr *ehdr = (void *)map_library(fd, &app);
1532 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1539 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1540 /* Find the name that would have been used for the dynamic
1541 * linker had ldd not taken its place. */
1543 for (i=0; i<app.phnum; i++) {
1544 if (app.phdr[i].p_type == PT_INTERP)
1545 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1547 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1551 app.tls_id = tls_cnt = 1;
1554 tls_offset = app.tls_size
1555 + ( -((uintptr_t)app.tls_image + app.tls_size)
1556 & (app.tls_align-1) );
1558 tls_offset = app.tls_offset = app.tls_size
1559 + ( -((uintptr_t)app.tls_image + app.tls_size)
1560 & (app.tls_align-1) );
1562 tls_align = MAXP2(tls_align, app.tls_align);
1567 makefuncdescs(&app);
1569 app.loadmap = (void *)&app_dummy_loadmap;
1570 app.loadmap->nsegs = 1;
1571 app.loadmap->segs[0].addr = (size_t)app.map;
1572 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1574 app.loadmap->segs[0].p_memsz = app.map_len;
1576 argv[-3] = (void *)app.loadmap;
1579 /* Attach to vdso, if provided by the kernel */
1580 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1581 Ehdr *ehdr = (void *)vdso_base;
1582 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1583 vdso.phnum = ehdr->e_phnum;
1584 vdso.phentsize = ehdr->e_phentsize;
1585 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1586 if (phdr->p_type == PT_DYNAMIC)
1587 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1588 if (phdr->p_type == PT_LOAD)
1589 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1592 vdso.shortname = "linux-gate.so.1";
1600 /* Initial dso chain consists only of the app. */
1603 /* Donate unused parts of app and library mapping to malloc */
1605 reclaim_gaps(&ldso);
1607 /* Load preload/needed libraries, add their symbols to the global
1608 * namespace, and perform all remaining relocations. */
1609 if (env_preload) load_preload(env_preload);
1613 #ifndef DYNAMIC_IS_RO
1614 for (i=0; app.dynv[i]; i+=2)
1615 if (app.dynv[i]==DT_DEBUG)
1616 app.dynv[i+1] = (size_t)&debug;
1619 /* The main program must be relocated LAST since it may contin
1620 * copy relocations which depend on libraries' relocations. */
1621 reloc_all(app.next);
1625 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1626 void *initial_tls = calloc(libc.tls_size, 1);
1628 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1629 argv[0], libc.tls_size);
1632 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1636 size_t tmp_tls_size = libc.tls_size;
1637 pthread_t self = __pthread_self();
1638 /* Temporarily set the tls size to the full size of
1639 * builtin_tls so that __copy_tls will use the same layout
1640 * as it did for before. Then check, just to be safe. */
1641 libc.tls_size = sizeof builtin_tls;
1642 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1643 libc.tls_size = tmp_tls_size;
1645 static_tls_cnt = tls_cnt;
1647 if (ldso_fail) _exit(127);
1648 if (ldd_mode) _exit(0);
1650 /* Switch to runtime mode: any further failures in the dynamic
1651 * linker are a reportable failure rather than a fatal startup
1656 debug.bp = dl_debug_state;
1658 debug.base = ldso.base;
1662 __init_libc(envp, argv[0]);
1666 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1670 void *dlopen(const char *file, int mode)
1672 struct dso *volatile p, *orig_tail, *next;
1673 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1678 if (!file) return head;
1680 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1681 pthread_rwlock_wrlock(&lock);
1685 orig_tls_cnt = tls_cnt;
1686 orig_tls_offset = tls_offset;
1687 orig_tls_align = tls_align;
1689 noload = mode & RTLD_NOLOAD;
1692 if (setjmp(*rtld_fail)) {
1693 /* Clean up anything new that was (partially) loaded */
1694 if (p && p->deps) for (i=0; p->deps[i]; i++)
1695 if (p->deps[i]->global < 0)
1696 p->deps[i]->global = 0;
1697 for (p=orig_tail->next; p; p=next) {
1699 while (p->td_index) {
1700 void *tmp = p->td_index->next;
1705 if (p->rpath != p->rpath_orig)
1711 tls_cnt = orig_tls_cnt;
1712 tls_offset = orig_tls_offset;
1713 tls_align = orig_tls_align;
1718 } else p = load_library(file, head);
1722 "Library %s is not already loaded" :
1723 "Error loading shared library %s: %m",
1728 /* First load handling */
1731 if (p->deps) for (i=0; p->deps[i]; i++)
1732 if (!p->deps[i]->global)
1733 p->deps[i]->global = -1;
1734 if (!p->global) p->global = -1;
1736 if (p->deps) for (i=0; p->deps[i]; i++)
1737 if (p->deps[i]->global < 0)
1738 p->deps[i]->global = 0;
1739 if (p->global < 0) p->global = 0;
1742 if (mode & RTLD_GLOBAL) {
1743 if (p->deps) for (i=0; p->deps[i]; i++)
1744 p->deps[i]->global = 1;
1754 pthread_rwlock_unlock(&lock);
1755 if (p) do_init_fini(orig_tail);
1756 pthread_setcancelstate(cs, 0);
1760 static int invalid_dso_handle(void *h)
1763 for (p=head; p; p=p->next) if (h==p) return 0;
1764 error("Invalid library handle %p", (void *)h);
1768 static void *addr2dso(size_t a)
1772 if (DL_FDPIC) for (p=head; p; p=p->next) {
1774 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1777 for (p=head; p; p=p->next) {
1778 if (DL_FDPIC && p->loadmap) {
1779 for (i=0; i<p->loadmap->nsegs; i++) {
1780 if (a-p->loadmap->segs[i].p_vaddr
1781 < p->loadmap->segs[i].p_memsz)
1785 if (a-(size_t)p->map < p->map_len)
1792 void *__tls_get_addr(size_t *);
1794 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1797 uint32_t h = 0, gh = 0, *ght;
1799 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1800 if (p == RTLD_DEFAULT) {
1802 } else if (p == RTLD_NEXT) {
1803 p = addr2dso((size_t)ra);
1807 struct symdef def = find_sym(p, s, 0);
1808 if (!def.sym) goto failed;
1809 if ((def.sym->st_info&0xf) == STT_TLS)
1810 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1811 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1812 return def.dso->funcdescs + (def.sym - def.dso->syms);
1813 return laddr(def.dso, def.sym->st_value);
1815 if (invalid_dso_handle(p))
1817 if ((ght = p->ghashtab)) {
1819 sym = gnu_lookup(gh, ght, p, s);
1822 sym = sysv_lookup(s, h, p);
1824 if (sym && (sym->st_info&0xf) == STT_TLS)
1825 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1826 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1827 return p->funcdescs + (sym - p->syms);
1828 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1829 return laddr(p, sym->st_value);
1830 if (p->deps) for (i=0; p->deps[i]; i++) {
1831 if ((ght = p->deps[i]->ghashtab)) {
1832 if (!gh) gh = gnu_hash(s);
1833 sym = gnu_lookup(gh, ght, p->deps[i], s);
1835 if (!h) h = sysv_hash(s);
1836 sym = sysv_lookup(s, h, p->deps[i]);
1838 if (sym && (sym->st_info&0xf) == STT_TLS)
1839 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1840 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1841 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1842 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1843 return laddr(p->deps[i], sym->st_value);
1846 error("Symbol not found: %s", s);
1850 int __dladdr(const void *addr, Dl_info *info)
1858 pthread_rwlock_rdlock(&lock);
1859 p = addr2dso((size_t)addr);
1860 pthread_rwlock_unlock(&lock);
1865 strings = p->strings;
1866 nsym = count_syms(p);
1869 size_t idx = ((size_t)addr-(size_t)p->funcdescs)
1870 / sizeof(*p->funcdescs);
1871 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1872 best = p->funcdescs + idx;
1873 bestsym = sym + idx;
1877 if (!best) for (; nsym; nsym--, sym++) {
1879 && (1<<(sym->st_info&0xf) & OK_TYPES)
1880 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1881 void *symaddr = laddr(p, sym->st_value);
1882 if (symaddr > addr || symaddr < best)
1886 if (addr == symaddr)
1891 if (!best) return 0;
1893 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
1894 best = p->funcdescs + (bestsym - p->syms);
1896 info->dli_fname = p->name;
1897 info->dli_fbase = p->base;
1898 info->dli_sname = strings + bestsym->st_name;
1899 info->dli_saddr = best;
1904 __attribute__((__visibility__("hidden")))
1905 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1908 pthread_rwlock_rdlock(&lock);
1909 res = do_dlsym(p, s, ra);
1910 pthread_rwlock_unlock(&lock);
1914 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1916 struct dso *current;
1917 struct dl_phdr_info info;
1919 for(current = head; current;) {
1920 info.dlpi_addr = (uintptr_t)current->base;
1921 info.dlpi_name = current->name;
1922 info.dlpi_phdr = current->phdr;
1923 info.dlpi_phnum = current->phnum;
1924 info.dlpi_adds = gencnt;
1926 info.dlpi_tls_modid = current->tls_id;
1927 info.dlpi_tls_data = current->tls_image;
1929 ret = (callback)(&info, sizeof (info), data);
1931 if (ret != 0) break;
1933 pthread_rwlock_rdlock(&lock);
1934 current = current->next;
1935 pthread_rwlock_unlock(&lock);
1940 static int invalid_dso_handle(void *h)
1942 error("Invalid library handle %p", (void *)h);
1945 void *dlopen(const char *file, int mode)
1947 error("Dynamic loading not supported");
1950 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1952 error("Symbol not found: %s", s);
1955 int __dladdr (const void *addr, Dl_info *info)
1961 int __dlinfo(void *dso, int req, void *res)
1963 if (invalid_dso_handle(dso)) return -1;
1964 if (req != RTLD_DI_LINKMAP) {
1965 error("Unsupported request %d", req);
1968 *(struct link_map **)res = dso;
1974 pthread_t self = __pthread_self();
1975 if (!self->dlerror_flag) return 0;
1976 self->dlerror_flag = 0;
1977 char *s = self->dlerror_buf;
1978 if (s == (void *)-1)
1979 return "Dynamic linker failed to allocate memory for error message";
1984 int dlclose(void *p)
1986 return invalid_dso_handle(p);
1989 void __dl_thread_cleanup(void)
1991 pthread_t self = __pthread_self();
1992 if (self->dlerror_buf != (void *)-1)
1993 free(self->dlerror_buf);
1996 static void error(const char *fmt, ...)
2002 vdprintf(2, fmt, ap);
2009 pthread_t self = __pthread_self();
2010 if (self->dlerror_buf != (void *)-1)
2011 free(self->dlerror_buf);
2012 size_t len = vsnprintf(0, 0, fmt, ap);
2014 char *buf = malloc(len+1);
2017 vsnprintf(buf, len+1, fmt, ap);
2022 self->dlerror_buf = buf;
2023 self->dlerror_flag = 1;