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 char *q = mmap(p, n, prot, flags, fd, off);
486 if (q != MAP_FAILED || errno != EINVAL) return q;
487 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
488 if (flags & MAP_ANONYMOUS) {
493 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
494 for (q=p; n; q+=r, off+=r, n-=r) {
496 if (r < 0 && errno != EINTR) return MAP_FAILED;
505 static void unmap_library(struct dso *dso)
509 for (i=0; i<dso->loadmap->nsegs; i++) {
510 if (!dso->loadmap->segs[i].p_memsz)
512 munmap((void *)dso->loadmap->segs[i].addr,
513 dso->loadmap->segs[i].p_memsz);
516 } else if (dso->map && dso->map_len) {
517 munmap(dso->map, dso->map_len);
521 static void *map_library(int fd, struct dso *dso)
523 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
524 void *allocated_buf=0;
526 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
527 size_t this_min, this_max;
533 unsigned char *map=MAP_FAILED, *base;
538 ssize_t l = read(fd, buf, sizeof buf);
541 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
543 phsize = eh->e_phentsize * eh->e_phnum;
544 if (phsize > sizeof buf - sizeof *eh) {
545 allocated_buf = malloc(phsize);
546 if (!allocated_buf) return 0;
547 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
548 if (l < 0) goto error;
549 if (l != phsize) goto noexec;
550 ph = ph0 = allocated_buf;
551 } else if (eh->e_phoff + phsize > l) {
552 l = pread(fd, buf+1, phsize, eh->e_phoff);
553 if (l < 0) goto error;
554 if (l != phsize) goto noexec;
555 ph = ph0 = (void *)(buf + 1);
557 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
559 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
560 if (ph->p_type == PT_DYNAMIC) {
562 } else if (ph->p_type == PT_TLS) {
563 tls_image = ph->p_vaddr;
564 dso->tls_align = ph->p_align;
565 dso->tls_len = ph->p_filesz;
566 dso->tls_size = ph->p_memsz;
567 } else if (ph->p_type == PT_GNU_RELRO) {
568 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
569 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
571 if (ph->p_type != PT_LOAD) continue;
573 if (ph->p_vaddr < addr_min) {
574 addr_min = ph->p_vaddr;
575 off_start = ph->p_offset;
576 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
577 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
578 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
580 if (ph->p_vaddr+ph->p_memsz > addr_max) {
581 addr_max = ph->p_vaddr+ph->p_memsz;
584 if (!dyn) goto noexec;
585 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
586 dso->loadmap = calloc(1, sizeof *dso->loadmap
587 + nsegs * sizeof *dso->loadmap->segs);
588 if (!dso->loadmap) goto error;
589 dso->loadmap->nsegs = nsegs;
590 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
591 if (ph->p_type != PT_LOAD) continue;
592 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
593 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
594 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
595 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
596 prot, (prot&PROT_WRITE) ? MAP_PRIVATE : MAP_SHARED,
597 fd, ph->p_offset & -PAGE_SIZE);
598 if (map == MAP_FAILED) {
602 dso->loadmap->segs[i].addr = (size_t)map +
603 (ph->p_vaddr & PAGE_SIZE-1);
604 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
605 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
607 if (prot & PROT_WRITE) {
608 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
610 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
611 size_t pgend = brk + ph->p_memsz - ph->p_filesz
612 + PAGE_SIZE-1 & -PAGE_SIZE;
613 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
615 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
616 -1, off_start) == MAP_FAILED)
618 memset(map + brk, 0, pgbrk-brk);
621 map = (void *)dso->loadmap->segs[0].addr;
625 addr_max += PAGE_SIZE-1;
626 addr_max &= -PAGE_SIZE;
627 addr_min &= -PAGE_SIZE;
628 off_start &= -PAGE_SIZE;
629 map_len = addr_max - addr_min + off_start;
630 /* The first time, we map too much, possibly even more than
631 * the length of the file. This is okay because we will not
632 * use the invalid part; we just need to reserve the right
633 * amount of virtual address space to map over later. */
634 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
635 if (map==MAP_FAILED) goto error;
637 dso->map_len = map_len;
638 /* If the loaded file is not relocatable and the requested address is
639 * not available, then the load operation must fail. */
640 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
644 base = map - addr_min;
647 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
648 if (ph->p_type != PT_LOAD) continue;
649 /* Check if the programs headers are in this load segment, and
650 * if so, record the address for use by dl_iterate_phdr. */
651 if (!dso->phdr && eh->e_phoff >= ph->p_offset
652 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
653 dso->phdr = (void *)(base + ph->p_vaddr
654 + (eh->e_phoff-ph->p_offset));
655 dso->phnum = eh->e_phnum;
656 dso->phentsize = eh->e_phentsize;
658 /* Reuse the existing mapping for the lowest-address LOAD */
659 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
660 this_min = ph->p_vaddr & -PAGE_SIZE;
661 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
662 off_start = ph->p_offset & -PAGE_SIZE;
663 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
664 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
665 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
666 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
668 if (ph->p_memsz > ph->p_filesz) {
669 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
670 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
671 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
672 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)
676 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
677 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
678 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
685 dso->dynv = laddr(dso, dyn);
686 if (dso->tls_size) dso->tls_image = laddr(dso, tls_image);
687 if (!runtime) reclaim_gaps(dso);
693 if (map!=MAP_FAILED) unmap_library(dso);
698 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
703 s += strspn(s, ":\n");
704 l = strcspn(s, ":\n");
705 if (l-1 >= INT_MAX) return -1;
706 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
707 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
715 /* Any negative value but -1 will inhibit
716 * futher path search. */
724 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
727 const char *s, *t, *origin;
729 if (p->rpath || !p->rpath_orig) return 0;
730 if (!strchr(p->rpath_orig, '$')) {
731 p->rpath = p->rpath_orig;
736 while ((t=strchr(s, '$'))) {
737 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
742 if (n > SSIZE_MAX/PATH_MAX) return 0;
744 if (p->kernel_mapped) {
745 /* $ORIGIN searches cannot be performed for the main program
746 * when it is suid/sgid/AT_SECURE. This is because the
747 * pathname is under the control of the caller of execve.
748 * For libraries, however, $ORIGIN can be processed safely
749 * since the library's pathname came from a trusted source
750 * (either system paths or a call to dlopen). */
753 l = readlink("/proc/self/exe", buf, buf_size);
754 if (l == -1) switch (errno) {
769 t = strrchr(origin, '/');
770 l = t ? t-origin : 0;
771 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
772 if (!p->rpath) return -1;
776 while ((t=strchr(s, '$'))) {
779 memcpy(d, origin, l);
781 /* It was determined previously that the '$' is followed
782 * either by "ORIGIN" or "{ORIGIN}". */
783 s = t + 7 + 2*(t[1]=='{');
789 static void decode_dyn(struct dso *p)
792 decode_vec(p->dynv, dyn, DYN_CNT);
793 p->syms = laddr(p, dyn[DT_SYMTAB]);
794 p->strings = laddr(p, dyn[DT_STRTAB]);
795 if (dyn[0]&(1<<DT_HASH))
796 p->hashtab = laddr(p, dyn[DT_HASH]);
797 if (dyn[0]&(1<<DT_RPATH))
798 p->rpath_orig = p->strings + dyn[DT_RPATH];
799 if (dyn[0]&(1<<DT_RUNPATH))
800 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
801 if (dyn[0]&(1<<DT_PLTGOT))
802 p->got = laddr(p, dyn[DT_PLTGOT]);
803 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
804 p->ghashtab = laddr(p, *dyn);
805 if (search_vec(p->dynv, dyn, DT_VERSYM))
806 p->versym = laddr(p, *dyn);
809 static size_t count_syms(struct dso *p)
811 if (p->hashtab) return p->hashtab[1];
814 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
816 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
817 if (buckets[i] > nsym)
821 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
823 while (!(*hashval++ & 1));
828 static void *dl_mmap(size_t n)
831 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
833 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
835 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
837 return p == MAP_FAILED ? 0 : p;
840 static void makefuncdescs(struct dso *p)
842 static int self_done;
843 size_t nsym = count_syms(p);
844 size_t i, size = nsym * sizeof(*p->funcdescs);
847 p->funcdescs = dl_mmap(size);
850 p->funcdescs = malloc(size);
853 if (!runtime) a_crash();
854 error("Error allocating function descriptors for %s", p->name);
855 longjmp(*rtld_fail, 1);
857 for (i=0; i<nsym; i++) {
858 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
859 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
860 p->funcdescs[i].got = p->got;
862 p->funcdescs[i].addr = 0;
863 p->funcdescs[i].got = 0;
868 static struct dso *load_library(const char *name, struct dso *needed_by)
870 char buf[2*NAME_MAX+2];
871 const char *pathname;
873 struct dso *p, temp_dso = {0};
885 /* Catch and block attempts to reload the implementation itself */
886 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
887 static const char *rp, reserved[] =
888 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
889 char *z = strchr(name, '.');
892 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
895 /* Track which names have been resolved
896 * and only report each one once. */
897 static unsigned reported;
898 unsigned mask = 1U<<(rp-reserved);
899 if (!(reported & mask)) {
901 dprintf(1, "\t%s => %s (%p)\n",
910 if (!strcmp(name, ldso.name)) is_self = 1;
915 tail = ldso.next ? ldso.next : &ldso;
919 if (strchr(name, '/')) {
921 fd = open(name, O_RDONLY|O_CLOEXEC);
923 /* Search for the name to see if it's already loaded */
924 for (p=head->next; p; p=p->next) {
925 if (p->shortname && !strcmp(p->shortname, name)) {
930 if (strlen(name) > NAME_MAX) return 0;
932 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
933 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
934 if (fixup_rpath(p, buf, sizeof buf) < 0)
935 fd = -2; /* Inhibit further search. */
937 fd = path_open(name, p->rpath, buf, sizeof buf);
943 if (ldso.name[0]=='/') {
945 for (s=t=z=ldso.name; *s; s++)
946 if (*s=='/') z=t, t=s;
947 prefix_len = z-ldso.name;
948 if (prefix_len < PATH_MAX)
955 char etc_ldso_path[prefix_len + 1
956 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
957 snprintf(etc_ldso_path, sizeof etc_ldso_path,
958 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
959 (int)prefix_len, prefix);
960 FILE *f = fopen(etc_ldso_path, "rbe");
962 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
967 } else if (errno != ENOENT) {
971 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
972 fd = path_open(name, sys_path, buf, sizeof buf);
976 if (fd < 0) return 0;
977 if (fstat(fd, &st) < 0) {
981 for (p=head->next; p; p=p->next) {
982 if (p->dev == st.st_dev && p->ino == st.st_ino) {
983 /* If this library was previously loaded with a
984 * pathname but a search found the same inode,
985 * setup its shortname so it can be found by name. */
986 if (!p->shortname && pathname != name)
987 p->shortname = strrchr(p->name, '/')+1;
993 map = noload ? 0 : map_library(fd, &temp_dso);
997 /* Allocate storage for the new DSO. When there is TLS, this
998 * storage must include a reservation for all pre-existing
999 * threads to obtain copies of both the new TLS, and an
1000 * extended DTV capable of storing an additional slot for
1001 * the newly-loaded DSO. */
1002 alloc_size = sizeof *p + strlen(pathname) + 1;
1003 if (runtime && temp_dso.tls_image) {
1004 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
1005 + sizeof(void *) * (tls_cnt+3);
1006 n_th = libc.threads_minus_1 + 1;
1007 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1008 else alloc_size += n_th * per_th;
1010 p = calloc(1, alloc_size);
1012 unmap_library(&temp_dso);
1015 memcpy(p, &temp_dso, sizeof temp_dso);
1020 p->needed_by = needed_by;
1022 strcpy(p->name, pathname);
1023 /* Add a shortname only if name arg was not an explicit pathname. */
1024 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1026 p->tls_id = ++tls_cnt;
1027 tls_align = MAXP2(tls_align, p->tls_align);
1029 p->tls_offset = tls_offset + ( (tls_align-1) &
1030 -(tls_offset + (uintptr_t)p->tls_image) );
1031 tls_offset += p->tls_size;
1033 tls_offset += p->tls_size + p->tls_align - 1;
1034 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
1036 p->tls_offset = tls_offset;
1038 p->new_dtv = (void *)(-sizeof(size_t) &
1039 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1040 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1047 if (DL_FDPIC) makefuncdescs(p);
1049 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1054 static void load_deps(struct dso *p)
1057 struct dso ***deps = &p->deps, **tmp, *dep;
1058 for (; p; p=p->next) {
1059 for (i=0; p->dynv[i]; i+=2) {
1060 if (p->dynv[i] != DT_NEEDED) continue;
1061 dep = load_library(p->strings + p->dynv[i+1], p);
1063 error("Error loading shared library %s: %m (needed by %s)",
1064 p->strings + p->dynv[i+1], p->name);
1065 if (runtime) longjmp(*rtld_fail, 1);
1069 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1070 if (!tmp) longjmp(*rtld_fail, 1);
1079 static void load_preload(char *s)
1083 for (z=s; *z; s=z) {
1084 for ( ; *s && (isspace(*s) || *s==':'); s++);
1085 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1093 static void make_global(struct dso *p)
1095 for (; p; p=p->next) p->global = 1;
1098 static void do_mips_relocs(struct dso *p, size_t *got)
1100 size_t i, j, rel[2];
1101 unsigned char *base = p->base;
1102 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1106 while (i--) *got++ += (size_t)base;
1108 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1109 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1110 Sym *sym = p->syms + j;
1111 rel[0] = (unsigned char *)got - base;
1112 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1113 rel[1] = sym-p->syms << 8 | R_MIPS_JUMP_SLOT;
1114 do_relocs(p, rel, sizeof rel, 2);
1118 static void reloc_all(struct dso *p)
1120 size_t dyn[DYN_CNT];
1121 for (; p; p=p->next) {
1122 if (p->relocated) continue;
1123 decode_vec(p->dynv, dyn, DYN_CNT);
1124 if (NEED_MIPS_GOT_RELOCS)
1125 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1126 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1127 2+(dyn[DT_PLTREL]==DT_RELA));
1128 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1129 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1131 if (head != &ldso && p->relro_start != p->relro_end &&
1132 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1133 && errno != ENOSYS) {
1134 error("Error relocating %s: RELRO protection failed: %m",
1136 if (runtime) longjmp(*rtld_fail, 1);
1143 static void kernel_mapped_dso(struct dso *p)
1145 size_t min_addr = -1, max_addr = 0, cnt;
1147 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1148 if (ph->p_type == PT_DYNAMIC) {
1149 p->dynv = laddr(p, ph->p_vaddr);
1150 } else if (ph->p_type == PT_GNU_RELRO) {
1151 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1152 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1154 if (ph->p_type != PT_LOAD) continue;
1155 if (ph->p_vaddr < min_addr)
1156 min_addr = ph->p_vaddr;
1157 if (ph->p_vaddr+ph->p_memsz > max_addr)
1158 max_addr = ph->p_vaddr+ph->p_memsz;
1160 min_addr &= -PAGE_SIZE;
1161 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1162 p->map = p->base + min_addr;
1163 p->map_len = max_addr - min_addr;
1164 p->kernel_mapped = 1;
1167 static void do_fini()
1170 size_t dyn[DYN_CNT];
1171 for (p=fini_head; p; p=p->fini_next) {
1172 if (!p->constructed) continue;
1173 decode_vec(p->dynv, dyn, DYN_CNT);
1174 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1175 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1176 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1177 while (n--) ((void (*)(void))*--fn)();
1179 #ifndef NO_LEGACY_INITFINI
1180 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1181 fpaddr(p, dyn[DT_FINI])();
1186 static void do_init_fini(struct dso *p)
1188 size_t dyn[DYN_CNT];
1189 int need_locking = libc.threads_minus_1;
1190 /* Allow recursive calls that arise when a library calls
1191 * dlopen from one of its constructors, but block any
1192 * other threads until all ctors have finished. */
1193 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1194 for (; p; p=p->prev) {
1195 if (p->constructed) continue;
1197 decode_vec(p->dynv, dyn, DYN_CNT);
1198 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1199 p->fini_next = fini_head;
1202 #ifndef NO_LEGACY_INITFINI
1203 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1204 fpaddr(p, dyn[DT_INIT])();
1206 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1207 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1208 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1209 while (n--) ((void (*)(void))*fn++)();
1211 if (!need_locking && libc.threads_minus_1) {
1213 pthread_mutex_lock(&init_fini_lock);
1216 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1219 void __libc_start_init(void)
1224 static void dl_debug_state(void)
1228 weak_alias(dl_debug_state, _dl_debug_state);
1232 pthread_t self = __pthread_self();
1234 for (p=head; p; p=p->next) {
1235 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
1236 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
1237 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
1238 p->tls_size - p->tls_len);
1239 if (p->tls_id == (size_t)self->dtv[0]) break;
1243 void *__copy_tls(unsigned char *mem)
1250 dtv = (void **)(mem + libc.tls_size) - (tls_cnt + 1);
1252 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
1253 td = (pthread_t)mem;
1254 mem += sizeof(struct pthread);
1256 for (p=head; p; p=p->next) {
1257 if (!p->tls_id) continue;
1258 dtv[p->tls_id] = mem + p->tls_offset;
1259 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1264 mem += libc.tls_size - sizeof(struct pthread);
1265 mem -= (uintptr_t)mem & (tls_align-1);
1266 td = (pthread_t)mem;
1268 for (p=head; p; p=p->next) {
1269 if (!p->tls_id) continue;
1270 dtv[p->tls_id] = mem - p->tls_offset;
1271 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1274 dtv[0] = (void *)tls_cnt;
1275 td->dtv = td->dtv_copy = dtv;
1279 __attribute__((__visibility__("hidden")))
1280 void *__tls_get_new(size_t *v)
1282 pthread_t self = __pthread_self();
1284 /* Block signals to make accessing new TLS async-signal-safe */
1286 __block_all_sigs(&set);
1287 if (v[0]<=(size_t)self->dtv[0]) {
1288 __restore_sigs(&set);
1289 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1292 /* This is safe without any locks held because, if the caller
1293 * is able to request the Nth entry of the DTV, the DSO list
1294 * must be valid at least that far out and it was synchronized
1295 * at program startup or by an already-completed call to dlopen. */
1297 for (p=head; p->tls_id != v[0]; p=p->next);
1299 /* Get new DTV space from new DSO if needed */
1300 if (v[0] > (size_t)self->dtv[0]) {
1301 void **newdtv = p->new_dtv +
1302 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1303 memcpy(newdtv, self->dtv,
1304 ((size_t)self->dtv[0]+1) * sizeof(void *));
1305 newdtv[0] = (void *)v[0];
1306 self->dtv = self->dtv_copy = newdtv;
1309 /* Get new TLS memory from all new DSOs up to the requested one */
1311 for (p=head; ; p=p->next) {
1312 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1313 mem = p->new_tls + (p->tls_size + p->tls_align)
1314 * a_fetch_add(&p->new_tls_idx,1);
1315 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
1317 self->dtv[p->tls_id] = mem;
1318 memcpy(mem, p->tls_image, p->tls_len);
1319 if (p->tls_id == v[0]) break;
1321 __restore_sigs(&set);
1322 return mem + v[1] + DTP_OFFSET;
1325 static void update_tls_size()
1327 libc.tls_size = ALIGN(
1328 (1+tls_cnt) * sizeof(void *) +
1330 sizeof(struct pthread) +
1335 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1336 * following stage 2 and stage 3 functions via primitive symbolic lookup
1337 * since it does not have access to their addresses to begin with. */
1339 /* Stage 2 of the dynamic linker is called after relative relocations
1340 * have been processed. It can make function calls to static functions
1341 * and access string literals and static data, but cannot use extern
1342 * symbols. Its job is to perform symbolic relocations on the dynamic
1343 * linker itself, but some of the relocations performed may need to be
1344 * replaced later due to copy relocations in the main program. */
1346 __attribute__((__visibility__("hidden")))
1347 void __dls2(unsigned char *base, size_t *sp)
1350 void *p1 = (void *)sp[-2];
1351 void *p2 = (void *)sp[-1];
1353 size_t *auxv, aux[AUX_CNT];
1354 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1355 decode_vec(auxv, aux, AUX_CNT);
1356 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1357 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1359 app_loadmap = p2 ? p1 : 0;
1360 ldso.loadmap = p2 ? p2 : p1;
1361 ldso.base = laddr(&ldso, 0);
1365 Ehdr *ehdr = (void *)ldso.base;
1366 ldso.name = ldso.shortname = "libc.so";
1368 ldso.phnum = ehdr->e_phnum;
1369 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1370 ldso.phentsize = ehdr->e_phentsize;
1371 kernel_mapped_dso(&ldso);
1374 if (DL_FDPIC) makefuncdescs(&ldso);
1376 /* Prepare storage for to save clobbered REL addends so they
1377 * can be reused in stage 3. There should be very few. If
1378 * something goes wrong and there are a huge number, abort
1379 * instead of risking stack overflow. */
1380 size_t dyn[DYN_CNT];
1381 decode_vec(ldso.dynv, dyn, DYN_CNT);
1382 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1383 size_t rel_size = dyn[DT_RELSZ];
1384 size_t symbolic_rel_cnt = 0;
1385 apply_addends_to = rel;
1386 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1387 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1388 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1389 size_t addends[symbolic_rel_cnt+1];
1390 saved_addends = addends;
1397 /* Call dynamic linker stage-3, __dls3, looking it up
1398 * symbolically as a barrier against moving the address
1399 * load across the above relocation processing. */
1400 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1401 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1402 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1405 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1406 * fully functional. Its job is to load (if not already loaded) and
1407 * process dependencies and relocations for the main application and
1408 * transfer control to its entry point. */
1410 _Noreturn void __dls3(size_t *sp)
1412 static struct dso app, vdso;
1413 size_t aux[AUX_CNT], *auxv;
1415 char *env_preload=0;
1418 char **argv = (void *)(sp+1);
1419 char **argv_orig = argv;
1420 char **envp = argv+argc+1;
1422 /* Find aux vector just past environ[] and use it to initialize
1423 * global data that may be needed before we can make syscalls. */
1425 for (i=argc+1; argv[i]; i++);
1426 libc.auxv = auxv = (void *)(argv+i+1);
1427 decode_vec(auxv, aux, AUX_CNT);
1428 __hwcap = aux[AT_HWCAP];
1429 libc.page_size = aux[AT_PAGESZ];
1430 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1431 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1433 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1434 * use during dynamic linking. If possible it will also serve as the
1435 * thread pointer at runtime. */
1436 libc.tls_size = sizeof builtin_tls;
1437 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1441 /* Only trust user/env if kernel says we're not suid/sgid */
1443 env_path = getenv("LD_LIBRARY_PATH");
1444 env_preload = getenv("LD_PRELOAD");
1447 /* If the main program was already loaded by the kernel,
1448 * AT_PHDR will point to some location other than the dynamic
1449 * linker's program headers. */
1450 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1451 size_t interp_off = 0;
1452 size_t tls_image = 0;
1453 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1454 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1455 app.phnum = aux[AT_PHNUM];
1456 app.phentsize = aux[AT_PHENT];
1457 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1458 if (phdr->p_type == PT_PHDR)
1459 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1460 else if (phdr->p_type == PT_INTERP)
1461 interp_off = (size_t)phdr->p_vaddr;
1462 else if (phdr->p_type == PT_TLS) {
1463 tls_image = phdr->p_vaddr;
1464 app.tls_len = phdr->p_filesz;
1465 app.tls_size = phdr->p_memsz;
1466 app.tls_align = phdr->p_align;
1469 if (DL_FDPIC) app.loadmap = app_loadmap;
1470 if (app.tls_size) app.tls_image = laddr(&app, tls_image);
1471 if (interp_off) ldso.name = laddr(&app, interp_off);
1472 if ((aux[0] & (1UL<<AT_EXECFN))
1473 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1474 app.name = (char *)aux[AT_EXECFN];
1477 kernel_mapped_dso(&app);
1480 char *ldname = argv[0];
1481 size_t l = strlen(ldname);
1482 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1484 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1485 char *opt = argv[0]+2;
1486 *argv++ = (void *)-1;
1489 } else if (!memcmp(opt, "list", 5)) {
1491 } else if (!memcmp(opt, "library-path", 12)) {
1492 if (opt[12]=='=') env_path = opt+13;
1493 else if (opt[12]) *argv = 0;
1494 else if (*argv) env_path = *argv++;
1495 } else if (!memcmp(opt, "preload", 7)) {
1496 if (opt[7]=='=') env_preload = opt+8;
1497 else if (opt[7]) *argv = 0;
1498 else if (*argv) env_preload = *argv++;
1503 argv[-1] = (void *)(argc - (argv-argv_orig));
1505 dprintf(2, "musl libc\n"
1507 "Dynamic Program Loader\n"
1508 "Usage: %s [options] [--] pathname%s\n",
1509 __libc_get_version(), ldname,
1510 ldd_mode ? "" : " [args]");
1513 fd = open(argv[0], O_RDONLY);
1515 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1519 Ehdr *ehdr = (void *)map_library(fd, &app);
1521 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1528 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1529 /* Find the name that would have been used for the dynamic
1530 * linker had ldd not taken its place. */
1532 for (i=0; i<app.phnum; i++) {
1533 if (app.phdr[i].p_type == PT_INTERP)
1534 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1536 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1540 app.tls_id = tls_cnt = 1;
1543 tls_offset = app.tls_size
1544 + ( -((uintptr_t)app.tls_image + app.tls_size)
1545 & (app.tls_align-1) );
1547 tls_offset = app.tls_offset = app.tls_size
1548 + ( -((uintptr_t)app.tls_image + app.tls_size)
1549 & (app.tls_align-1) );
1551 tls_align = MAXP2(tls_align, app.tls_align);
1556 makefuncdescs(&app);
1558 app.loadmap = (void *)&app_dummy_loadmap;
1559 app.loadmap->nsegs = 1;
1560 app.loadmap->segs[0].addr = (size_t)app.map;
1561 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1563 app.loadmap->segs[0].p_memsz = app.map_len;
1565 argv[-3] = (void *)app.loadmap;
1568 /* Attach to vdso, if provided by the kernel */
1569 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1570 Ehdr *ehdr = (void *)vdso_base;
1571 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1572 vdso.phnum = ehdr->e_phnum;
1573 vdso.phentsize = ehdr->e_phentsize;
1574 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1575 if (phdr->p_type == PT_DYNAMIC)
1576 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1577 if (phdr->p_type == PT_LOAD)
1578 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1581 vdso.shortname = "linux-gate.so.1";
1589 /* Initial dso chain consists only of the app. */
1592 /* Donate unused parts of app and library mapping to malloc */
1594 reclaim_gaps(&ldso);
1596 /* Load preload/needed libraries, add their symbols to the global
1597 * namespace, and perform all remaining relocations. */
1598 if (env_preload) load_preload(env_preload);
1602 #ifndef DYNAMIC_IS_RO
1603 for (i=0; app.dynv[i]; i+=2)
1604 if (app.dynv[i]==DT_DEBUG)
1605 app.dynv[i+1] = (size_t)&debug;
1608 /* The main program must be relocated LAST since it may contin
1609 * copy relocations which depend on libraries' relocations. */
1610 reloc_all(app.next);
1614 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1615 void *initial_tls = calloc(libc.tls_size, 1);
1617 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1618 argv[0], libc.tls_size);
1621 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1625 size_t tmp_tls_size = libc.tls_size;
1626 pthread_t self = __pthread_self();
1627 /* Temporarily set the tls size to the full size of
1628 * builtin_tls so that __copy_tls will use the same layout
1629 * as it did for before. Then check, just to be safe. */
1630 libc.tls_size = sizeof builtin_tls;
1631 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1632 libc.tls_size = tmp_tls_size;
1634 static_tls_cnt = tls_cnt;
1636 if (ldso_fail) _exit(127);
1637 if (ldd_mode) _exit(0);
1639 /* Switch to runtime mode: any further failures in the dynamic
1640 * linker are a reportable failure rather than a fatal startup
1645 debug.bp = dl_debug_state;
1647 debug.base = ldso.base;
1651 __init_libc(envp, argv[0]);
1655 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1659 void *dlopen(const char *file, int mode)
1661 struct dso *volatile p, *orig_tail, *next;
1662 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1667 if (!file) return head;
1669 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1670 pthread_rwlock_wrlock(&lock);
1674 orig_tls_cnt = tls_cnt;
1675 orig_tls_offset = tls_offset;
1676 orig_tls_align = tls_align;
1678 noload = mode & RTLD_NOLOAD;
1681 if (setjmp(*rtld_fail)) {
1682 /* Clean up anything new that was (partially) loaded */
1683 if (p && p->deps) for (i=0; p->deps[i]; i++)
1684 if (p->deps[i]->global < 0)
1685 p->deps[i]->global = 0;
1686 for (p=orig_tail->next; p; p=next) {
1688 while (p->td_index) {
1689 void *tmp = p->td_index->next;
1694 if (p->rpath != p->rpath_orig)
1700 tls_cnt = orig_tls_cnt;
1701 tls_offset = orig_tls_offset;
1702 tls_align = orig_tls_align;
1707 } else p = load_library(file, head);
1711 "Library %s is not already loaded" :
1712 "Error loading shared library %s: %m",
1717 /* First load handling */
1720 if (p->deps) for (i=0; p->deps[i]; i++)
1721 if (!p->deps[i]->global)
1722 p->deps[i]->global = -1;
1723 if (!p->global) p->global = -1;
1725 if (p->deps) for (i=0; p->deps[i]; i++)
1726 if (p->deps[i]->global < 0)
1727 p->deps[i]->global = 0;
1728 if (p->global < 0) p->global = 0;
1731 if (mode & RTLD_GLOBAL) {
1732 if (p->deps) for (i=0; p->deps[i]; i++)
1733 p->deps[i]->global = 1;
1743 pthread_rwlock_unlock(&lock);
1744 if (p) do_init_fini(orig_tail);
1745 pthread_setcancelstate(cs, 0);
1749 static int invalid_dso_handle(void *h)
1752 for (p=head; p; p=p->next) if (h==p) return 0;
1753 error("Invalid library handle %p", (void *)h);
1757 static void *addr2dso(size_t a)
1761 if (DL_FDPIC) for (p=head; p; p=p->next) {
1763 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1766 for (p=head; p; p=p->next) {
1767 if (DL_FDPIC && p->loadmap) {
1768 for (i=0; i<p->loadmap->nsegs; i++) {
1769 if (a-p->loadmap->segs[i].p_vaddr
1770 < p->loadmap->segs[i].p_memsz)
1774 if (a-(size_t)p->map < p->map_len)
1781 void *__tls_get_addr(size_t *);
1783 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1786 uint32_t h = 0, gh = 0, *ght;
1788 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1789 if (p == RTLD_DEFAULT) {
1791 } else if (p == RTLD_NEXT) {
1792 p = addr2dso((size_t)ra);
1796 struct symdef def = find_sym(p, s, 0);
1797 if (!def.sym) goto failed;
1798 if ((def.sym->st_info&0xf) == STT_TLS)
1799 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1800 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1801 return def.dso->funcdescs + (def.sym - def.dso->syms);
1802 return laddr(def.dso, def.sym->st_value);
1804 if (invalid_dso_handle(p))
1806 if ((ght = p->ghashtab)) {
1808 sym = gnu_lookup(gh, ght, p, s);
1811 sym = sysv_lookup(s, h, p);
1813 if (sym && (sym->st_info&0xf) == STT_TLS)
1814 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1815 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1816 return p->funcdescs + (sym - p->syms);
1817 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1818 return laddr(p, sym->st_value);
1819 if (p->deps) for (i=0; p->deps[i]; i++) {
1820 if ((ght = p->deps[i]->ghashtab)) {
1821 if (!gh) gh = gnu_hash(s);
1822 sym = gnu_lookup(gh, ght, p->deps[i], s);
1824 if (!h) h = sysv_hash(s);
1825 sym = sysv_lookup(s, h, p->deps[i]);
1827 if (sym && (sym->st_info&0xf) == STT_TLS)
1828 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1829 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1830 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1831 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1832 return laddr(p->deps[i], sym->st_value);
1835 error("Symbol not found: %s", s);
1839 int __dladdr(const void *addr, Dl_info *info)
1847 pthread_rwlock_rdlock(&lock);
1848 p = addr2dso((size_t)addr);
1849 pthread_rwlock_unlock(&lock);
1854 strings = p->strings;
1855 nsym = count_syms(p);
1858 size_t idx = ((size_t)addr-(size_t)p->funcdescs)
1859 / sizeof(*p->funcdescs);
1860 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1861 best = p->funcdescs + idx;
1862 bestsym = sym + idx;
1866 if (!best) for (; nsym; nsym--, sym++) {
1868 && (1<<(sym->st_info&0xf) & OK_TYPES)
1869 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1870 void *symaddr = laddr(p, sym->st_value);
1871 if (symaddr > addr || symaddr < best)
1875 if (addr == symaddr)
1880 if (!best) return 0;
1882 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
1883 best = p->funcdescs + (bestsym - p->syms);
1885 info->dli_fname = p->name;
1886 info->dli_fbase = p->base;
1887 info->dli_sname = strings + bestsym->st_name;
1888 info->dli_saddr = best;
1893 __attribute__((__visibility__("hidden")))
1894 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1897 pthread_rwlock_rdlock(&lock);
1898 res = do_dlsym(p, s, ra);
1899 pthread_rwlock_unlock(&lock);
1903 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1905 struct dso *current;
1906 struct dl_phdr_info info;
1908 for(current = head; current;) {
1909 info.dlpi_addr = (uintptr_t)current->base;
1910 info.dlpi_name = current->name;
1911 info.dlpi_phdr = current->phdr;
1912 info.dlpi_phnum = current->phnum;
1913 info.dlpi_adds = gencnt;
1915 info.dlpi_tls_modid = current->tls_id;
1916 info.dlpi_tls_data = current->tls_image;
1918 ret = (callback)(&info, sizeof (info), data);
1920 if (ret != 0) break;
1922 pthread_rwlock_rdlock(&lock);
1923 current = current->next;
1924 pthread_rwlock_unlock(&lock);
1929 static int invalid_dso_handle(void *h)
1931 error("Invalid library handle %p", (void *)h);
1934 void *dlopen(const char *file, int mode)
1936 error("Dynamic loading not supported");
1939 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1941 error("Symbol not found: %s", s);
1944 int __dladdr (const void *addr, Dl_info *info)
1950 int __dlinfo(void *dso, int req, void *res)
1952 if (invalid_dso_handle(dso)) return -1;
1953 if (req != RTLD_DI_LINKMAP) {
1954 error("Unsupported request %d", req);
1957 *(struct link_map **)res = dso;
1963 pthread_t self = __pthread_self();
1964 if (!self->dlerror_flag) return 0;
1965 self->dlerror_flag = 0;
1966 char *s = self->dlerror_buf;
1967 if (s == (void *)-1)
1968 return "Dynamic linker failed to allocate memory for error message";
1973 int dlclose(void *p)
1975 return invalid_dso_handle(p);
1978 void __dl_thread_cleanup(void)
1980 pthread_t self = __pthread_self();
1981 if (self->dlerror_buf != (void *)-1)
1982 free(self->dlerror_buf);
1985 static void error(const char *fmt, ...)
1991 vdprintf(2, fmt, ap);
1998 pthread_t self = __pthread_self();
1999 if (self->dlerror_buf != (void *)-1)
2000 free(self->dlerror_buf);
2001 size_t len = vsnprintf(0, 0, fmt, ap);
2003 char *buf = malloc(len+1);
2006 vsnprintf(buf, len+1, fmt, ap);
2011 self->dlerror_buf = buf;
2012 self->dlerror_flag = 1;