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;
608 map = (void *)dso->loadmap->segs[0].addr;
612 addr_max += PAGE_SIZE-1;
613 addr_max &= -PAGE_SIZE;
614 addr_min &= -PAGE_SIZE;
615 off_start &= -PAGE_SIZE;
616 map_len = addr_max - addr_min + off_start;
617 /* The first time, we map too much, possibly even more than
618 * the length of the file. This is okay because we will not
619 * use the invalid part; we just need to reserve the right
620 * amount of virtual address space to map over later. */
621 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
622 if (map==MAP_FAILED) goto error;
624 dso->map_len = map_len;
625 /* If the loaded file is not relocatable and the requested address is
626 * not available, then the load operation must fail. */
627 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
631 base = map - addr_min;
634 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
635 if (ph->p_type != PT_LOAD) continue;
636 /* Check if the programs headers are in this load segment, and
637 * if so, record the address for use by dl_iterate_phdr. */
638 if (!dso->phdr && eh->e_phoff >= ph->p_offset
639 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
640 dso->phdr = (void *)(base + ph->p_vaddr
641 + (eh->e_phoff-ph->p_offset));
642 dso->phnum = eh->e_phnum;
643 dso->phentsize = eh->e_phentsize;
645 /* Reuse the existing mapping for the lowest-address LOAD */
646 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
647 this_min = ph->p_vaddr & -PAGE_SIZE;
648 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
649 off_start = ph->p_offset & -PAGE_SIZE;
650 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
651 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
652 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
653 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
655 if (ph->p_memsz > ph->p_filesz) {
656 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
657 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
658 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
659 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)
663 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
664 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
665 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
672 dso->dynv = laddr(dso, dyn);
673 if (dso->tls_size) dso->tls_image = laddr(dso, tls_image);
674 if (!runtime) reclaim_gaps(dso);
680 if (map!=MAP_FAILED) unmap_library(dso);
685 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
690 s += strspn(s, ":\n");
691 l = strcspn(s, ":\n");
692 if (l-1 >= INT_MAX) return -1;
693 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
694 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
702 /* Any negative value but -1 will inhibit
703 * futher path search. */
711 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
714 const char *s, *t, *origin;
716 if (p->rpath || !p->rpath_orig) return 0;
717 if (!strchr(p->rpath_orig, '$')) {
718 p->rpath = p->rpath_orig;
723 while ((t=strchr(s, '$'))) {
724 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
729 if (n > SSIZE_MAX/PATH_MAX) return 0;
731 if (p->kernel_mapped) {
732 /* $ORIGIN searches cannot be performed for the main program
733 * when it is suid/sgid/AT_SECURE. This is because the
734 * pathname is under the control of the caller of execve.
735 * For libraries, however, $ORIGIN can be processed safely
736 * since the library's pathname came from a trusted source
737 * (either system paths or a call to dlopen). */
740 l = readlink("/proc/self/exe", buf, buf_size);
741 if (l == -1) switch (errno) {
756 t = strrchr(origin, '/');
757 l = t ? t-origin : 0;
758 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
759 if (!p->rpath) return -1;
763 while ((t=strchr(s, '$'))) {
766 memcpy(d, origin, l);
768 /* It was determined previously that the '$' is followed
769 * either by "ORIGIN" or "{ORIGIN}". */
770 s = t + 7 + 2*(t[1]=='{');
776 static void decode_dyn(struct dso *p)
779 decode_vec(p->dynv, dyn, DYN_CNT);
780 p->syms = laddr(p, dyn[DT_SYMTAB]);
781 p->strings = laddr(p, dyn[DT_STRTAB]);
782 if (dyn[0]&(1<<DT_HASH))
783 p->hashtab = laddr(p, dyn[DT_HASH]);
784 if (dyn[0]&(1<<DT_RPATH))
785 p->rpath_orig = p->strings + dyn[DT_RPATH];
786 if (dyn[0]&(1<<DT_RUNPATH))
787 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
788 if (dyn[0]&(1<<DT_PLTGOT))
789 p->got = laddr(p, dyn[DT_PLTGOT]);
790 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
791 p->ghashtab = laddr(p, *dyn);
792 if (search_vec(p->dynv, dyn, DT_VERSYM))
793 p->versym = laddr(p, *dyn);
796 static size_t count_syms(struct dso *p)
798 if (p->hashtab) return p->hashtab[1];
801 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
803 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
804 if (buckets[i] > nsym)
808 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
810 while (!(*hashval++ & 1));
815 static void *dl_mmap(size_t n)
818 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
820 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
822 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
824 return p == MAP_FAILED ? 0 : p;
827 static void makefuncdescs(struct dso *p)
829 static int self_done;
830 size_t nsym = count_syms(p);
831 size_t i, size = nsym * sizeof(*p->funcdescs);
834 p->funcdescs = dl_mmap(size);
837 p->funcdescs = malloc(size);
840 if (!runtime) a_crash();
841 error("Error allocating function descriptors for %s", p->name);
842 longjmp(*rtld_fail, 1);
844 for (i=0; i<nsym; i++) {
845 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
846 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
847 p->funcdescs[i].got = p->got;
849 p->funcdescs[i].addr = 0;
850 p->funcdescs[i].got = 0;
855 static struct dso *load_library(const char *name, struct dso *needed_by)
857 char buf[2*NAME_MAX+2];
858 const char *pathname;
860 struct dso *p, temp_dso = {0};
872 /* Catch and block attempts to reload the implementation itself */
873 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
874 static const char *rp, reserved[] =
875 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
876 char *z = strchr(name, '.');
879 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
882 /* Track which names have been resolved
883 * and only report each one once. */
884 static unsigned reported;
885 unsigned mask = 1U<<(rp-reserved);
886 if (!(reported & mask)) {
888 dprintf(1, "\t%s => %s (%p)\n",
897 if (!strcmp(name, ldso.name)) is_self = 1;
902 tail = ldso.next ? ldso.next : &ldso;
906 if (strchr(name, '/')) {
908 fd = open(name, O_RDONLY|O_CLOEXEC);
910 /* Search for the name to see if it's already loaded */
911 for (p=head->next; p; p=p->next) {
912 if (p->shortname && !strcmp(p->shortname, name)) {
917 if (strlen(name) > NAME_MAX) return 0;
919 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
920 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
921 if (fixup_rpath(p, buf, sizeof buf) < 0)
922 fd = -2; /* Inhibit further search. */
924 fd = path_open(name, p->rpath, buf, sizeof buf);
930 if (ldso.name[0]=='/') {
932 for (s=t=z=ldso.name; *s; s++)
933 if (*s=='/') z=t, t=s;
934 prefix_len = z-ldso.name;
935 if (prefix_len < PATH_MAX)
942 char etc_ldso_path[prefix_len + 1
943 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
944 snprintf(etc_ldso_path, sizeof etc_ldso_path,
945 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
946 (int)prefix_len, prefix);
947 FILE *f = fopen(etc_ldso_path, "rbe");
949 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
954 } else if (errno != ENOENT) {
958 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
959 fd = path_open(name, sys_path, buf, sizeof buf);
963 if (fd < 0) return 0;
964 if (fstat(fd, &st) < 0) {
968 for (p=head->next; p; p=p->next) {
969 if (p->dev == st.st_dev && p->ino == st.st_ino) {
970 /* If this library was previously loaded with a
971 * pathname but a search found the same inode,
972 * setup its shortname so it can be found by name. */
973 if (!p->shortname && pathname != name)
974 p->shortname = strrchr(p->name, '/')+1;
980 map = noload ? 0 : map_library(fd, &temp_dso);
984 /* Allocate storage for the new DSO. When there is TLS, this
985 * storage must include a reservation for all pre-existing
986 * threads to obtain copies of both the new TLS, and an
987 * extended DTV capable of storing an additional slot for
988 * the newly-loaded DSO. */
989 alloc_size = sizeof *p + strlen(pathname) + 1;
990 if (runtime && temp_dso.tls_image) {
991 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
992 + sizeof(void *) * (tls_cnt+3);
993 n_th = libc.threads_minus_1 + 1;
994 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
995 else alloc_size += n_th * per_th;
997 p = calloc(1, alloc_size);
999 unmap_library(&temp_dso);
1002 memcpy(p, &temp_dso, sizeof temp_dso);
1007 p->needed_by = needed_by;
1009 strcpy(p->name, pathname);
1010 /* Add a shortname only if name arg was not an explicit pathname. */
1011 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1013 p->tls_id = ++tls_cnt;
1014 tls_align = MAXP2(tls_align, p->tls_align);
1016 p->tls_offset = tls_offset + ( (tls_align-1) &
1017 -(tls_offset + (uintptr_t)p->tls_image) );
1018 tls_offset += p->tls_size;
1020 tls_offset += p->tls_size + p->tls_align - 1;
1021 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
1023 p->tls_offset = tls_offset;
1025 p->new_dtv = (void *)(-sizeof(size_t) &
1026 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1027 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1034 if (DL_FDPIC) makefuncdescs(p);
1036 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1041 static void load_deps(struct dso *p)
1044 struct dso ***deps = &p->deps, **tmp, *dep;
1045 for (; p; p=p->next) {
1046 for (i=0; p->dynv[i]; i+=2) {
1047 if (p->dynv[i] != DT_NEEDED) continue;
1048 dep = load_library(p->strings + p->dynv[i+1], p);
1050 error("Error loading shared library %s: %m (needed by %s)",
1051 p->strings + p->dynv[i+1], p->name);
1052 if (runtime) longjmp(*rtld_fail, 1);
1056 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1057 if (!tmp) longjmp(*rtld_fail, 1);
1066 static void load_preload(char *s)
1070 for (z=s; *z; s=z) {
1071 for ( ; *s && (isspace(*s) || *s==':'); s++);
1072 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1080 static void make_global(struct dso *p)
1082 for (; p; p=p->next) p->global = 1;
1085 static void do_mips_relocs(struct dso *p, size_t *got)
1087 size_t i, j, rel[2];
1088 unsigned char *base = p->base;
1089 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1093 while (i--) *got++ += (size_t)base;
1095 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1096 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1097 Sym *sym = p->syms + j;
1098 rel[0] = (unsigned char *)got - base;
1099 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1100 rel[1] = sym-p->syms << 8 | R_MIPS_JUMP_SLOT;
1101 do_relocs(p, rel, sizeof rel, 2);
1105 static void reloc_all(struct dso *p)
1107 size_t dyn[DYN_CNT];
1108 for (; p; p=p->next) {
1109 if (p->relocated) continue;
1110 decode_vec(p->dynv, dyn, DYN_CNT);
1111 if (NEED_MIPS_GOT_RELOCS)
1112 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1113 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1114 2+(dyn[DT_PLTREL]==DT_RELA));
1115 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1116 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1118 if (head != &ldso && p->relro_start != p->relro_end &&
1119 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1120 && errno != ENOSYS) {
1121 error("Error relocating %s: RELRO protection failed: %m",
1123 if (runtime) longjmp(*rtld_fail, 1);
1130 static void kernel_mapped_dso(struct dso *p)
1132 size_t min_addr = -1, max_addr = 0, cnt;
1134 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1135 if (ph->p_type == PT_DYNAMIC) {
1136 p->dynv = laddr(p, ph->p_vaddr);
1137 } else if (ph->p_type == PT_GNU_RELRO) {
1138 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1139 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1141 if (ph->p_type != PT_LOAD) continue;
1142 if (ph->p_vaddr < min_addr)
1143 min_addr = ph->p_vaddr;
1144 if (ph->p_vaddr+ph->p_memsz > max_addr)
1145 max_addr = ph->p_vaddr+ph->p_memsz;
1147 min_addr &= -PAGE_SIZE;
1148 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1149 p->map = p->base + min_addr;
1150 p->map_len = max_addr - min_addr;
1151 p->kernel_mapped = 1;
1154 static void do_fini()
1157 size_t dyn[DYN_CNT];
1158 for (p=fini_head; p; p=p->fini_next) {
1159 if (!p->constructed) continue;
1160 decode_vec(p->dynv, dyn, DYN_CNT);
1161 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1162 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1163 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1164 while (n--) ((void (*)(void))*--fn)();
1166 #ifndef NO_LEGACY_INITFINI
1167 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1168 fpaddr(p, dyn[DT_FINI])();
1173 static void do_init_fini(struct dso *p)
1175 size_t dyn[DYN_CNT];
1176 int need_locking = libc.threads_minus_1;
1177 /* Allow recursive calls that arise when a library calls
1178 * dlopen from one of its constructors, but block any
1179 * other threads until all ctors have finished. */
1180 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1181 for (; p; p=p->prev) {
1182 if (p->constructed) continue;
1184 decode_vec(p->dynv, dyn, DYN_CNT);
1185 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1186 p->fini_next = fini_head;
1189 #ifndef NO_LEGACY_INITFINI
1190 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1191 fpaddr(p, dyn[DT_INIT])();
1193 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1194 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1195 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1196 while (n--) ((void (*)(void))*fn++)();
1198 if (!need_locking && libc.threads_minus_1) {
1200 pthread_mutex_lock(&init_fini_lock);
1203 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1206 static void dl_debug_state(void)
1210 weak_alias(dl_debug_state, _dl_debug_state);
1214 pthread_t self = __pthread_self();
1216 for (p=head; p; p=p->next) {
1217 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
1218 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
1219 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
1220 p->tls_size - p->tls_len);
1221 if (p->tls_id == (size_t)self->dtv[0]) break;
1225 void *__copy_tls(unsigned char *mem)
1232 dtv = (void **)(mem + libc.tls_size) - (tls_cnt + 1);
1234 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
1235 td = (pthread_t)mem;
1236 mem += sizeof(struct pthread);
1238 for (p=head; p; p=p->next) {
1239 if (!p->tls_id) continue;
1240 dtv[p->tls_id] = mem + p->tls_offset;
1241 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1246 mem += libc.tls_size - sizeof(struct pthread);
1247 mem -= (uintptr_t)mem & (tls_align-1);
1248 td = (pthread_t)mem;
1250 for (p=head; p; p=p->next) {
1251 if (!p->tls_id) continue;
1252 dtv[p->tls_id] = mem - p->tls_offset;
1253 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1256 dtv[0] = (void *)tls_cnt;
1257 td->dtv = td->dtv_copy = dtv;
1261 __attribute__((__visibility__("hidden")))
1262 void *__tls_get_new(size_t *v)
1264 pthread_t self = __pthread_self();
1266 /* Block signals to make accessing new TLS async-signal-safe */
1268 __block_all_sigs(&set);
1269 if (v[0]<=(size_t)self->dtv[0]) {
1270 __restore_sigs(&set);
1271 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1274 /* This is safe without any locks held because, if the caller
1275 * is able to request the Nth entry of the DTV, the DSO list
1276 * must be valid at least that far out and it was synchronized
1277 * at program startup or by an already-completed call to dlopen. */
1279 for (p=head; p->tls_id != v[0]; p=p->next);
1281 /* Get new DTV space from new DSO if needed */
1282 if (v[0] > (size_t)self->dtv[0]) {
1283 void **newdtv = p->new_dtv +
1284 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1285 memcpy(newdtv, self->dtv,
1286 ((size_t)self->dtv[0]+1) * sizeof(void *));
1287 newdtv[0] = (void *)v[0];
1288 self->dtv = self->dtv_copy = newdtv;
1291 /* Get new TLS memory from all new DSOs up to the requested one */
1293 for (p=head; ; p=p->next) {
1294 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1295 mem = p->new_tls + (p->tls_size + p->tls_align)
1296 * a_fetch_add(&p->new_tls_idx,1);
1297 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
1299 self->dtv[p->tls_id] = mem;
1300 memcpy(mem, p->tls_image, p->tls_len);
1301 if (p->tls_id == v[0]) break;
1303 __restore_sigs(&set);
1304 return mem + v[1] + DTP_OFFSET;
1307 static void update_tls_size()
1309 libc.tls_size = ALIGN(
1310 (1+tls_cnt) * sizeof(void *) +
1312 sizeof(struct pthread) +
1317 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1318 * following stage 2 and stage 3 functions via primitive symbolic lookup
1319 * since it does not have access to their addresses to begin with. */
1321 /* Stage 2 of the dynamic linker is called after relative relocations
1322 * have been processed. It can make function calls to static functions
1323 * and access string literals and static data, but cannot use extern
1324 * symbols. Its job is to perform symbolic relocations on the dynamic
1325 * linker itself, but some of the relocations performed may need to be
1326 * replaced later due to copy relocations in the main program. */
1328 void __dls2(unsigned char *base, size_t *sp)
1331 void *p1 = (void *)sp[-2];
1332 void *p2 = (void *)sp[-1];
1334 size_t *auxv, aux[AUX_CNT];
1335 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1336 decode_vec(auxv, aux, AUX_CNT);
1337 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1338 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1340 app_loadmap = p2 ? p1 : 0;
1341 ldso.loadmap = p2 ? p2 : p1;
1342 ldso.base = laddr(&ldso, 0);
1346 Ehdr *ehdr = (void *)ldso.base;
1347 ldso.name = ldso.shortname = "libc.so";
1349 ldso.phnum = ehdr->e_phnum;
1350 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1351 ldso.phentsize = ehdr->e_phentsize;
1352 kernel_mapped_dso(&ldso);
1355 if (DL_FDPIC) makefuncdescs(&ldso);
1357 /* Prepare storage for to save clobbered REL addends so they
1358 * can be reused in stage 3. There should be very few. If
1359 * something goes wrong and there are a huge number, abort
1360 * instead of risking stack overflow. */
1361 size_t dyn[DYN_CNT];
1362 decode_vec(ldso.dynv, dyn, DYN_CNT);
1363 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1364 size_t rel_size = dyn[DT_RELSZ];
1365 size_t symbolic_rel_cnt = 0;
1366 apply_addends_to = rel;
1367 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1368 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1369 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1370 size_t addends[symbolic_rel_cnt+1];
1371 saved_addends = addends;
1378 /* Call dynamic linker stage-3, __dls3, looking it up
1379 * symbolically as a barrier against moving the address
1380 * load across the above relocation processing. */
1381 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1382 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1383 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1386 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1387 * fully functional. Its job is to load (if not already loaded) and
1388 * process dependencies and relocations for the main application and
1389 * transfer control to its entry point. */
1391 _Noreturn void __dls3(size_t *sp)
1393 static struct dso app, vdso;
1394 size_t aux[AUX_CNT], *auxv;
1396 char *env_preload=0;
1399 char **argv = (void *)(sp+1);
1400 char **argv_orig = argv;
1401 char **envp = argv+argc+1;
1403 /* Find aux vector just past environ[] and use it to initialize
1404 * global data that may be needed before we can make syscalls. */
1406 for (i=argc+1; argv[i]; i++);
1407 libc.auxv = auxv = (void *)(argv+i+1);
1408 decode_vec(auxv, aux, AUX_CNT);
1409 __hwcap = aux[AT_HWCAP];
1410 libc.page_size = aux[AT_PAGESZ];
1411 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1412 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1414 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1415 * use during dynamic linking. If possible it will also serve as the
1416 * thread pointer at runtime. */
1417 libc.tls_size = sizeof builtin_tls;
1418 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1422 /* Only trust user/env if kernel says we're not suid/sgid */
1424 env_path = getenv("LD_LIBRARY_PATH");
1425 env_preload = getenv("LD_PRELOAD");
1428 /* If the main program was already loaded by the kernel,
1429 * AT_PHDR will point to some location other than the dynamic
1430 * linker's program headers. */
1431 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1432 size_t interp_off = 0;
1433 size_t tls_image = 0;
1434 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1435 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1436 app.phnum = aux[AT_PHNUM];
1437 app.phentsize = aux[AT_PHENT];
1438 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1439 if (phdr->p_type == PT_PHDR)
1440 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1441 else if (phdr->p_type == PT_INTERP)
1442 interp_off = (size_t)phdr->p_vaddr;
1443 else if (phdr->p_type == PT_TLS) {
1444 tls_image = phdr->p_vaddr;
1445 app.tls_len = phdr->p_filesz;
1446 app.tls_size = phdr->p_memsz;
1447 app.tls_align = phdr->p_align;
1450 if (DL_FDPIC) app.loadmap = app_loadmap;
1451 if (app.tls_size) app.tls_image = laddr(&app, tls_image);
1452 if (interp_off) ldso.name = laddr(&app, interp_off);
1453 if ((aux[0] & (1UL<<AT_EXECFN))
1454 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1455 app.name = (char *)aux[AT_EXECFN];
1458 kernel_mapped_dso(&app);
1461 char *ldname = argv[0];
1462 size_t l = strlen(ldname);
1463 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1465 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1466 char *opt = argv[0]+2;
1467 *argv++ = (void *)-1;
1470 } else if (!memcmp(opt, "list", 5)) {
1472 } else if (!memcmp(opt, "library-path", 12)) {
1473 if (opt[12]=='=') env_path = opt+13;
1474 else if (opt[12]) *argv = 0;
1475 else if (*argv) env_path = *argv++;
1476 } else if (!memcmp(opt, "preload", 7)) {
1477 if (opt[7]=='=') env_preload = opt+8;
1478 else if (opt[7]) *argv = 0;
1479 else if (*argv) env_preload = *argv++;
1484 argv[-1] = (void *)(argc - (argv-argv_orig));
1486 dprintf(2, "musl libc\n"
1488 "Dynamic Program Loader\n"
1489 "Usage: %s [options] [--] pathname%s\n",
1490 __libc_get_version(), ldname,
1491 ldd_mode ? "" : " [args]");
1494 fd = open(argv[0], O_RDONLY);
1496 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1500 Ehdr *ehdr = (void *)map_library(fd, &app);
1502 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1509 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1510 /* Find the name that would have been used for the dynamic
1511 * linker had ldd not taken its place. */
1513 for (i=0; i<app.phnum; i++) {
1514 if (app.phdr[i].p_type == PT_INTERP)
1515 ldso.name = (void *)(app.base
1516 + app.phdr[i].p_vaddr);
1518 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1522 app.tls_id = tls_cnt = 1;
1525 tls_offset = app.tls_size
1526 + ( -((uintptr_t)app.tls_image + app.tls_size)
1527 & (app.tls_align-1) );
1529 tls_offset = app.tls_offset = app.tls_size
1530 + ( -((uintptr_t)app.tls_image + app.tls_size)
1531 & (app.tls_align-1) );
1533 tls_align = MAXP2(tls_align, app.tls_align);
1538 makefuncdescs(&app);
1540 app.loadmap = (void *)&app_dummy_loadmap;
1541 app.loadmap->nsegs = 1;
1542 app.loadmap->segs[0].addr = (size_t)app.base;
1543 app.loadmap->segs[0].p_memsz = -1;
1545 argv[-3] = (void *)app.loadmap;
1548 /* Attach to vdso, if provided by the kernel */
1549 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1550 Ehdr *ehdr = (void *)vdso_base;
1551 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1552 vdso.phnum = ehdr->e_phnum;
1553 vdso.phentsize = ehdr->e_phentsize;
1554 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1555 if (phdr->p_type == PT_DYNAMIC)
1556 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1557 if (phdr->p_type == PT_LOAD)
1558 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1561 vdso.shortname = "linux-gate.so.1";
1569 /* Initial dso chain consists only of the app. */
1572 /* Donate unused parts of app and library mapping to malloc */
1574 reclaim_gaps(&ldso);
1576 /* Load preload/needed libraries, add their symbols to the global
1577 * namespace, and perform all remaining relocations. */
1578 if (env_preload) load_preload(env_preload);
1582 #ifndef DYNAMIC_IS_RO
1583 for (i=0; app.dynv[i]; i+=2)
1584 if (app.dynv[i]==DT_DEBUG)
1585 app.dynv[i+1] = (size_t)&debug;
1588 /* The main program must be relocated LAST since it may contin
1589 * copy relocations which depend on libraries' relocations. */
1590 reloc_all(app.next);
1594 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1595 void *initial_tls = calloc(libc.tls_size, 1);
1597 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1598 argv[0], libc.tls_size);
1601 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1605 size_t tmp_tls_size = libc.tls_size;
1606 pthread_t self = __pthread_self();
1607 /* Temporarily set the tls size to the full size of
1608 * builtin_tls so that __copy_tls will use the same layout
1609 * as it did for before. Then check, just to be safe. */
1610 libc.tls_size = sizeof builtin_tls;
1611 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1612 libc.tls_size = tmp_tls_size;
1614 static_tls_cnt = tls_cnt;
1616 if (ldso_fail) _exit(127);
1617 if (ldd_mode) _exit(0);
1619 /* Switch to runtime mode: any further failures in the dynamic
1620 * linker are a reportable failure rather than a fatal startup
1625 debug.bp = dl_debug_state;
1627 debug.base = ldso.base;
1631 __init_libc(envp, argv[0]);
1636 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1640 void *dlopen(const char *file, int mode)
1642 struct dso *volatile p, *orig_tail, *next;
1643 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1648 if (!file) return head;
1650 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1651 pthread_rwlock_wrlock(&lock);
1655 orig_tls_cnt = tls_cnt;
1656 orig_tls_offset = tls_offset;
1657 orig_tls_align = tls_align;
1659 noload = mode & RTLD_NOLOAD;
1662 if (setjmp(*rtld_fail)) {
1663 /* Clean up anything new that was (partially) loaded */
1664 if (p && p->deps) for (i=0; p->deps[i]; i++)
1665 if (p->deps[i]->global < 0)
1666 p->deps[i]->global = 0;
1667 for (p=orig_tail->next; p; p=next) {
1669 while (p->td_index) {
1670 void *tmp = p->td_index->next;
1675 if (p->rpath != p->rpath_orig)
1681 tls_cnt = orig_tls_cnt;
1682 tls_offset = orig_tls_offset;
1683 tls_align = orig_tls_align;
1688 } else p = load_library(file, head);
1692 "Library %s is not already loaded" :
1693 "Error loading shared library %s: %m",
1698 /* First load handling */
1701 if (p->deps) for (i=0; p->deps[i]; i++)
1702 if (!p->deps[i]->global)
1703 p->deps[i]->global = -1;
1704 if (!p->global) p->global = -1;
1706 if (p->deps) for (i=0; p->deps[i]; i++)
1707 if (p->deps[i]->global < 0)
1708 p->deps[i]->global = 0;
1709 if (p->global < 0) p->global = 0;
1712 if (mode & RTLD_GLOBAL) {
1713 if (p->deps) for (i=0; p->deps[i]; i++)
1714 p->deps[i]->global = 1;
1724 pthread_rwlock_unlock(&lock);
1725 if (p) do_init_fini(orig_tail);
1726 pthread_setcancelstate(cs, 0);
1730 static int invalid_dso_handle(void *h)
1733 for (p=head; p; p=p->next) if (h==p) return 0;
1734 error("Invalid library handle %p", (void *)h);
1738 void *__tls_get_addr(size_t *);
1740 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1743 uint32_t h = 0, gh = 0, *ght;
1745 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1746 if (p == RTLD_DEFAULT) {
1748 } else if (p == RTLD_NEXT) {
1749 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1753 struct symdef def = find_sym(p, s, 0);
1754 if (!def.sym) goto failed;
1755 if ((def.sym->st_info&0xf) == STT_TLS)
1756 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1757 return laddr(def.dso, def.sym->st_value);
1759 if (invalid_dso_handle(p))
1761 if ((ght = p->ghashtab)) {
1763 sym = gnu_lookup(gh, ght, p, s);
1766 sym = sysv_lookup(s, h, p);
1768 if (sym && (sym->st_info&0xf) == STT_TLS)
1769 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1770 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1771 return laddr(p, sym->st_value);
1772 if (p->deps) for (i=0; p->deps[i]; i++) {
1773 if ((ght = p->deps[i]->ghashtab)) {
1774 if (!gh) gh = gnu_hash(s);
1775 sym = gnu_lookup(gh, ght, p->deps[i], s);
1777 if (!h) h = sysv_hash(s);
1778 sym = sysv_lookup(s, h, p->deps[i]);
1780 if (sym && (sym->st_info&0xf) == STT_TLS)
1781 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1782 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1783 return laddr(p->deps[i], sym->st_value);
1786 error("Symbol not found: %s", s);
1790 int __dladdr(const void *addr, Dl_info *info)
1799 pthread_rwlock_rdlock(&lock);
1800 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1801 pthread_rwlock_unlock(&lock);
1806 strings = p->strings;
1807 nsym = count_syms(p);
1809 for (; nsym; nsym--, sym++) {
1811 && (1<<(sym->st_info&0xf) & OK_TYPES)
1812 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1813 void *symaddr = laddr(p, sym->st_value);
1814 if (symaddr > addr || symaddr < best)
1817 bestname = strings + sym->st_name;
1818 if (addr == symaddr)
1823 if (!best) return 0;
1825 info->dli_fname = p->name;
1826 info->dli_fbase = p->base;
1827 info->dli_sname = bestname;
1828 info->dli_saddr = best;
1833 __attribute__((__visibility__("hidden")))
1834 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1837 pthread_rwlock_rdlock(&lock);
1838 res = do_dlsym(p, s, ra);
1839 pthread_rwlock_unlock(&lock);
1843 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1845 struct dso *current;
1846 struct dl_phdr_info info;
1848 for(current = head; current;) {
1849 info.dlpi_addr = (uintptr_t)current->base;
1850 info.dlpi_name = current->name;
1851 info.dlpi_phdr = current->phdr;
1852 info.dlpi_phnum = current->phnum;
1853 info.dlpi_adds = gencnt;
1855 info.dlpi_tls_modid = current->tls_id;
1856 info.dlpi_tls_data = current->tls_image;
1858 ret = (callback)(&info, sizeof (info), data);
1860 if (ret != 0) break;
1862 pthread_rwlock_rdlock(&lock);
1863 current = current->next;
1864 pthread_rwlock_unlock(&lock);
1869 static int invalid_dso_handle(void *h)
1871 error("Invalid library handle %p", (void *)h);
1874 void *dlopen(const char *file, int mode)
1876 error("Dynamic loading not supported");
1879 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1881 error("Symbol not found: %s", s);
1884 int __dladdr (const void *addr, Dl_info *info)
1890 int __dlinfo(void *dso, int req, void *res)
1892 if (invalid_dso_handle(dso)) return -1;
1893 if (req != RTLD_DI_LINKMAP) {
1894 error("Unsupported request %d", req);
1897 *(struct link_map **)res = dso;
1903 pthread_t self = __pthread_self();
1904 if (!self->dlerror_flag) return 0;
1905 self->dlerror_flag = 0;
1906 char *s = self->dlerror_buf;
1907 if (s == (void *)-1)
1908 return "Dynamic linker failed to allocate memory for error message";
1913 int dlclose(void *p)
1915 return invalid_dso_handle(p);
1918 void __dl_thread_cleanup(void)
1920 pthread_t self = __pthread_self();
1921 if (self->dlerror_buf != (void *)-1)
1922 free(self->dlerror_buf);
1925 static void error(const char *fmt, ...)
1931 vdprintf(2, fmt, ap);
1938 pthread_t self = __pthread_self();
1939 if (self->dlerror_buf != (void *)-1)
1940 free(self->dlerror_buf);
1941 size_t len = vsnprintf(0, 0, fmt, ap);
1943 char *buf = malloc(len+1);
1946 vsnprintf(buf, len+1, fmt, ap);
1951 self->dlerror_buf = buf;
1952 self->dlerror_flag = 1;