ldso/dynlink.c

   1 #define _GNU_SOURCE
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <stdarg.h>
   5 #include <stddef.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <stdint.h>
   9 #include <elf.h>
  10 #include <sys/mman.h>
  11 #include <limits.h>
  12 #include <fcntl.h>
  13 #include <sys/stat.h>
  14 #include <errno.h>
  15 #include <link.h>
  16 #include <setjmp.h>
  17 #include <pthread.h>
  18 #include <ctype.h>
  19 #include <dlfcn.h>
  20 #include <semaphore.h>
  21 #include <sys/membarrier.h>
  22 #include "pthread_impl.h"
  23 #include "libc.h"
  24 #include "dynlink.h"
  25 #include "malloc_impl.h"
  26
  27 static void error(const char *, ...);
  28
  29 #define MAXP2(a,b) (-(-(a)&-(b)))
  30 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  31
  32 struct debug {
  33         int ver;
  34         void *head;
  35         void (*bp)(void);
  36         int state;
  37         void *base;
  38 };
  39
  40 struct td_index {
  41         size_t args[2];
  42         struct td_index *next;
  43 };
  44
  45 struct dso {
  46 #if DL_FDPIC
  47         struct fdpic_loadmap *loadmap;
  48 #else
  49         unsigned char *base;
  50 #endif
  51         char *name;
  52         size_t *dynv;
  53         struct dso *next, *prev;
  54
  55         Phdr *phdr;
  56         int phnum;
  57         size_t phentsize;
  58         Sym *syms;
  59         Elf_Symndx *hashtab;
  60         uint32_t *ghashtab;
  61         int16_t *versym;
  62         char *strings;
  63         struct dso *syms_next, *lazy_next;
  64         size_t *lazy, lazy_cnt;
  65         unsigned char *map;
  66         size_t map_len;
  67         dev_t dev;
  68         ino_t ino;
  69         char relocated;
  70         char constructed;
  71         char kernel_mapped;
  72         struct dso **deps, *needed_by;
  73         char *rpath_orig, *rpath;
  74         struct tls_module tls;
  75         size_t tls_id;
  76         size_t relro_start, relro_end;
  77         uintptr_t *new_dtv;
  78         unsigned char *new_tls;
  79         volatile int new_dtv_idx, new_tls_idx;
  80         struct td_index *td_index;
  81         struct dso *fini_next;
  82         char *shortname;
  83 #if DL_FDPIC
  84         unsigned char *base;
  85 #else
  86         struct fdpic_loadmap *loadmap;
  87 #endif
  88         struct funcdesc {
  89                 void *addr;
  90                 size_t *got;
  91         } *funcdescs;
  92         size_t *got;
  93         char buf[];
  94 };
  95
  96 struct symdef {
  97         Sym *sym;
  98         struct dso *dso;
  99 };
 100
 101 static struct builtin_tls {
 102         char c;
 103         struct pthread pt;
 104         void *space[16];
 105 } builtin_tls[1];
 106 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
 107
 108 #define ADDEND_LIMIT 4096
 109 static size_t *saved_addends, *apply_addends_to;
 110
 111 static struct dso ldso;
 112 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
 113 static char *env_path, *sys_path;
 114 static unsigned long long gencnt;
 115 static int runtime;
 116 static int ldd_mode;
 117 static int ldso_fail;
 118 static int noload;
 119 static jmp_buf *rtld_fail;
 120 static pthread_rwlock_t lock;
 121 static struct debug debug;
 122 static struct tls_module *tls_tail;
 123 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
 124 static size_t static_tls_cnt;
 125 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 126 static struct fdpic_loadmap *app_loadmap;
 127 static struct fdpic_dummy_loadmap app_dummy_loadmap;
 128 static struct dso *const nodeps_dummy;
 129
 130 struct debug *_dl_debug_addr = &debug;
 131
 132 extern hidden int __malloc_replaced;
 133
 134 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
 135
 136 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
 137
 138 weak_alias(__init_array_start, __init_array_end);
 139 weak_alias(__fini_array_start, __fini_array_end);
 140
 141 static int dl_strcmp(const char *l, const char *r)
 142 {
 143         for (; *l==*r && *l; l++, r++);
 144         return *(unsigned char *)l - *(unsigned char *)r;
 145 }
 146 #define strcmp(l,r) dl_strcmp(l,r)
 147
 148 /* Compute load address for a virtual address in a given dso. */
 149 #if DL_FDPIC
 150 static void *laddr(const struct dso *p, size_t v)
 151 {
 152         size_t j=0;
 153         if (!p->loadmap) return p->base + v;
 154         for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
 155         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 156 }
 157 static void *laddr_pg(const struct dso *p, size_t v)
 158 {
 159         size_t j=0;
 160         size_t pgsz = PAGE_SIZE;
 161         if (!p->loadmap) return p->base + v;
 162         for (j=0; ; j++) {
 163                 size_t a = p->loadmap->segs[j].p_vaddr;
 164                 size_t b = a + p->loadmap->segs[j].p_memsz;
 165                 a &= -pgsz;
 166                 b += pgsz-1;
 167                 b &= -pgsz;
 168                 if (v-a<b-a) break;
 169         }
 170         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 171 }
 172 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
 173         laddr(p, v), (p)->got })
 174 #else
 175 #define laddr(p, v) (void *)((p)->base + (v))
 176 #define laddr_pg(p, v) laddr(p, v)
 177 #define fpaddr(p, v) ((void (*)())laddr(p, v))
 178 #endif
 179
 180 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 181 {
 182         size_t i;
 183         for (i=0; i<cnt; i++) a[i] = 0;
 184         for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
 185                 a[0] |= 1UL<<v[0];
 186                 a[v[0]] = v[1];
 187         }
 188 }
 189
 190 static int search_vec(size_t *v, size_t *r, size_t key)
 191 {
 192         for (; v[0]!=key; v+=2)
 193                 if (!v[0]) return 0;
 194         *r = v[1];
 195         return 1;
 196 }
 197
 198 static uint32_t sysv_hash(const char *s0)
 199 {
 200         const unsigned char *s = (void *)s0;
 201         uint_fast32_t h = 0;
 202         while (*s) {
 203                 h = 16*h + *s++;
 204                 h ^= h>>24 & 0xf0;
 205         }
 206         return h & 0xfffffff;
 207 }
 208
 209 static uint32_t gnu_hash(const char *s0)
 210 {
 211         const unsigned char *s = (void *)s0;
 212         uint_fast32_t h = 5381;
 213         for (; *s; s++)
 214                 h += h*32 + *s;
 215         return h;
 216 }
 217
 218 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 219 {
 220         size_t i;
 221         Sym *syms = dso->syms;
 222         Elf_Symndx *hashtab = dso->hashtab;
 223         char *strings = dso->strings;
 224         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 225                 if ((!dso->versym || dso->versym[i] >= 0)
 226                     && (!strcmp(s, strings+syms[i].st_name)))
 227                         return syms+i;
 228         }
 229         return 0;
 230 }
 231
 232 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
 233 {
 234         uint32_t nbuckets = hashtab[0];
 235         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 236         uint32_t i = buckets[h1 % nbuckets];
 237
 238         if (!i) return 0;
 239
 240         uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
 241
 242         for (h1 |= 1; ; i++) {
 243                 uint32_t h2 = *hashval++;
 244                 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
 245                     && !strcmp(s, dso->strings + dso->syms[i].st_name))
 246                         return dso->syms+i;
 247                 if (h2 & 1) break;
 248         }
 249
 250         return 0;
 251 }
 252
 253 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
 254 {
 255         const size_t *bloomwords = (const void *)(hashtab+4);
 256         size_t f = bloomwords[fofs & (hashtab[2]-1)];
 257         if (!(f & fmask)) return 0;
 258
 259         f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
 260         if (!(f & 1)) return 0;
 261
 262         return gnu_lookup(h1, hashtab, dso, s);
 263 }
 264
 265 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 266 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 267
 268 #ifndef ARCH_SYM_REJECT_UND
 269 #define ARCH_SYM_REJECT_UND(s) 0
 270 #endif
 271
 272 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 273 {
 274         uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
 275         size_t ghm = 1ul << gh % (8*sizeof(size_t));
 276         struct symdef def = {0};
 277         for (; dso; dso=dso->syms_next) {
 278                 Sym *sym;
 279                 if ((ght = dso->ghashtab)) {
 280                         sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
 281                 } else {
 282                         if (!h) h = sysv_hash(s);
 283                         sym = sysv_lookup(s, h, dso);
 284                 }
 285                 if (!sym) continue;
 286                 if (!sym->st_shndx)
 287                         if (need_def || (sym->st_info&0xf) == STT_TLS
 288                             || ARCH_SYM_REJECT_UND(sym))
 289                                 continue;
 290                 if (!sym->st_value)
 291                         if ((sym->st_info&0xf) != STT_TLS)
 292                                 continue;
 293                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 294                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 295                 def.sym = sym;
 296                 def.dso = dso;
 297                 break;
 298         }
 299         return def;
 300 }
 301
 302 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 303 {
 304         unsigned char *base = dso->base;
 305         Sym *syms = dso->syms;
 306         char *strings = dso->strings;
 307         Sym *sym;
 308         const char *name;
 309         void *ctx;
 310         int type;
 311         int sym_index;
 312         struct symdef def;
 313         size_t *reloc_addr;
 314         size_t sym_val;
 315         size_t tls_val;
 316         size_t addend;
 317         int skip_relative = 0, reuse_addends = 0, save_slot = 0;
 318
 319         if (dso == &ldso) {
 320                 /* Only ldso's REL table needs addend saving/reuse. */
 321                 if (rel == apply_addends_to)
 322                         reuse_addends = 1;
 323                 skip_relative = 1;
 324         }
 325
 326         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 327                 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
 328                 type = R_TYPE(rel[1]);
 329                 if (type == REL_NONE) continue;
 330                 reloc_addr = laddr(dso, rel[0]);
 331
 332                 if (stride > 2) {
 333                         addend = rel[2];
 334                 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
 335                         addend = 0;
 336                 } else if (reuse_addends) {
 337                         /* Save original addend in stage 2 where the dso
 338                          * chain consists of just ldso; otherwise read back
 339                          * saved addend since the inline one was clobbered. */
 340                         if (head==&ldso)
 341                                 saved_addends[save_slot] = *reloc_addr;
 342                         addend = saved_addends[save_slot++];
 343                 } else {
 344                         addend = *reloc_addr;
 345                 }
 346
 347                 sym_index = R_SYM(rel[1]);
 348                 if (sym_index) {
 349                         sym = syms + sym_index;
 350                         name = strings + sym->st_name;
 351                         ctx = type==REL_COPY ? head->syms_next : head;
 352                         def = (sym->st_info&0xf) == STT_SECTION
 353                                 ? (struct symdef){ .dso = dso, .sym = sym }
 354                                 : find_sym(ctx, name, type==REL_PLT);
 355                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 356                             || sym->st_info>>4 != STB_WEAK)) {
 357                                 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
 358                                         dso->lazy[3*dso->lazy_cnt+0] = rel[0];
 359                                         dso->lazy[3*dso->lazy_cnt+1] = rel[1];
 360                                         dso->lazy[3*dso->lazy_cnt+2] = addend;
 361                                         dso->lazy_cnt++;
 362                                         continue;
 363                                 }
 364                                 error("Error relocating %s: %s: symbol not found",
 365                                         dso->name, name);
 366                                 if (runtime) longjmp(*rtld_fail, 1);
 367                                 continue;
 368                         }
 369                 } else {
 370                         sym = 0;
 371                         def.sym = 0;
 372                         def.dso = dso;
 373                 }
 374
 375                 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
 376                 tls_val = def.sym ? def.sym->st_value : 0;
 377
 378                 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
 379                     && runtime && def.dso->tls_id > static_tls_cnt) {
 380                         error("Error relocating %s: %s: initial-exec TLS "
 381                                 "resolves to dynamic definition in %s",
 382                                 dso->name, name, def.dso->name);
 383                         longjmp(*rtld_fail, 1);
 384                 }
 385
 386                 switch(type) {
 387                 case REL_NONE:
 388                         break;
 389                 case REL_OFFSET:
 390                         addend -= (size_t)reloc_addr;
 391                 case REL_SYMBOLIC:
 392                 case REL_GOT:
 393                 case REL_PLT:
 394                         *reloc_addr = sym_val + addend;
 395                         break;
 396                 case REL_RELATIVE:
 397                         *reloc_addr = (size_t)base + addend;
 398                         break;
 399                 case REL_SYM_OR_REL:
 400                         if (sym) *reloc_addr = sym_val + addend;
 401                         else *reloc_addr = (size_t)base + addend;
 402                         break;
 403                 case REL_COPY:
 404                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 405                         break;
 406                 case REL_OFFSET32:
 407                         *(uint32_t *)reloc_addr = sym_val + addend
 408                                 - (size_t)reloc_addr;
 409                         break;
 410                 case REL_FUNCDESC:
 411                         *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
 412                                 + (def.sym - def.dso->syms)) : 0;
 413                         break;
 414                 case REL_FUNCDESC_VAL:
 415                         if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
 416                         else *reloc_addr = sym_val;
 417                         reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
 418                         break;
 419                 case REL_DTPMOD:
 420                         *reloc_addr = def.dso->tls_id;
 421                         break;
 422                 case REL_DTPOFF:
 423                         *reloc_addr = tls_val + addend - DTP_OFFSET;
 424                         break;
 425 #ifdef TLS_ABOVE_TP
 426                 case REL_TPOFF:
 427                         *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
 428                         break;
 429 #else
 430                 case REL_TPOFF:
 431                         *reloc_addr = tls_val - def.dso->tls.offset + addend;
 432                         break;
 433                 case REL_TPOFF_NEG:
 434                         *reloc_addr = def.dso->tls.offset - tls_val + addend;
 435                         break;
 436 #endif
 437                 case REL_TLSDESC:
 438                         if (stride<3) addend = reloc_addr[1];
 439                         if (runtime && def.dso->tls_id > static_tls_cnt) {
 440                                 struct td_index *new = malloc(sizeof *new);
 441                                 if (!new) {
 442                                         error(
 443                                         "Error relocating %s: cannot allocate TLSDESC for %s",
 444                                         dso->name, sym ? name : "(local)" );
 445                                         longjmp(*rtld_fail, 1);
 446                                 }
 447                                 new->next = dso->td_index;
 448                                 dso->td_index = new;
 449                                 new->args[0] = def.dso->tls_id;
 450                                 new->args[1] = tls_val + addend - DTP_OFFSET;
 451                                 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
 452                                 reloc_addr[1] = (size_t)new;
 453                         } else {
 454                                 reloc_addr[0] = (size_t)__tlsdesc_static;
 455 #ifdef TLS_ABOVE_TP
 456                                 reloc_addr[1] = tls_val + def.dso->tls.offset
 457                                         + TPOFF_K + addend;
 458 #else
 459                                 reloc_addr[1] = tls_val - def.dso->tls.offset
 460                                         + addend;
 461 #endif
 462                         }
 463 #ifdef TLSDESC_BACKWARDS
 464                         /* Some archs (32-bit ARM at least) invert the order of
 465                          * the descriptor members. Fix them up here. */
 466                         size_t tmp = reloc_addr[0];
 467                         reloc_addr[0] = reloc_addr[1];
 468                         reloc_addr[1] = tmp;
 469 #endif
 470                         break;
 471                 default:
 472                         error("Error relocating %s: unsupported relocation type %d",
 473                                 dso->name, type);
 474                         if (runtime) longjmp(*rtld_fail, 1);
 475                         continue;
 476                 }
 477         }
 478 }
 479
 480 static void redo_lazy_relocs()
 481 {
 482         struct dso *p = lazy_head, *next;
 483         lazy_head = 0;
 484         for (; p; p=next) {
 485                 next = p->lazy_next;
 486                 size_t size = p->lazy_cnt*3*sizeof(size_t);
 487                 p->lazy_cnt = 0;
 488                 do_relocs(p, p->lazy, size, 3);
 489                 if (p->lazy_cnt) {
 490                         p->lazy_next = lazy_head;
 491                         lazy_head = p;
 492                 } else {
 493                         free(p->lazy);
 494                         p->lazy = 0;
 495                         p->lazy_next = 0;
 496                 }
 497         }
 498 }
 499
 500 /* A huge hack: to make up for the wastefulness of shared libraries
 501  * needing at least a page of dirty memory even if they have no global
 502  * data, we reclaim the gaps at the beginning and end of writable maps
 503  * and "donate" them to the heap. */
 504
 505 static void reclaim(struct dso *dso, size_t start, size_t end)
 506 {
 507         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 508         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 509         if (start >= end) return;
 510         char *base = laddr_pg(dso, start);
 511         __malloc_donate(base, base+(end-start));
 512 }
 513
 514 static void reclaim_gaps(struct dso *dso)
 515 {
 516         Phdr *ph = dso->phdr;
 517         size_t phcnt = dso->phnum;
 518
 519         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 520                 if (ph->p_type!=PT_LOAD) continue;
 521                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 522                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 523                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 524                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 525         }
 526 }
 527
 528 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
 529 {
 530         static int no_map_fixed;
 531         char *q;
 532         if (!no_map_fixed) {
 533                 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
 534                 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
 535                         return q;
 536                 no_map_fixed = 1;
 537         }
 538         /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
 539         if (flags & MAP_ANONYMOUS) {
 540                 memset(p, 0, n);
 541                 return p;
 542         }
 543         ssize_t r;
 544         if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
 545         for (q=p; n; q+=r, off+=r, n-=r) {
 546                 r = read(fd, q, n);
 547                 if (r < 0 && errno != EINTR) return MAP_FAILED;
 548                 if (!r) {
 549                         memset(q, 0, n);
 550                         break;
 551                 }
 552         }
 553         return p;
 554 }
 555
 556 static void unmap_library(struct dso *dso)
 557 {
 558         if (dso->loadmap) {
 559                 size_t i;
 560                 for (i=0; i<dso->loadmap->nsegs; i++) {
 561                         if (!dso->loadmap->segs[i].p_memsz)
 562                                 continue;
 563                         munmap((void *)dso->loadmap->segs[i].addr,
 564                                 dso->loadmap->segs[i].p_memsz);
 565                 }
 566                 free(dso->loadmap);
 567         } else if (dso->map && dso->map_len) {
 568                 munmap(dso->map, dso->map_len);
 569         }
 570 }
 571
 572 static void *map_library(int fd, struct dso *dso)
 573 {
 574         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 575         void *allocated_buf=0;
 576         size_t phsize;
 577         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 578         size_t this_min, this_max;
 579         size_t nsegs = 0;
 580         off_t off_start;
 581         Ehdr *eh;
 582         Phdr *ph, *ph0;
 583         unsigned prot;
 584         unsigned char *map=MAP_FAILED, *base;
 585         size_t dyn=0;
 586         size_t tls_image=0;
 587         size_t i;
 588
 589         ssize_t l = read(fd, buf, sizeof buf);
 590         eh = buf;
 591         if (l<0) return 0;
 592         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 593                 goto noexec;
 594         phsize = eh->e_phentsize * eh->e_phnum;
 595         if (phsize > sizeof buf - sizeof *eh) {
 596                 allocated_buf = malloc(phsize);
 597                 if (!allocated_buf) return 0;
 598                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 599                 if (l < 0) goto error;
 600                 if (l != phsize) goto noexec;
 601                 ph = ph0 = allocated_buf;
 602         } else if (eh->e_phoff + phsize > l) {
 603                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 604                 if (l < 0) goto error;
 605                 if (l != phsize) goto noexec;
 606                 ph = ph0 = (void *)(buf + 1);
 607         } else {
 608                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 609         }
 610         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 611                 if (ph->p_type == PT_DYNAMIC) {
 612                         dyn = ph->p_vaddr;
 613                 } else if (ph->p_type == PT_TLS) {
 614                         tls_image = ph->p_vaddr;
 615                         dso->tls.align = ph->p_align;
 616                         dso->tls.len = ph->p_filesz;
 617                         dso->tls.size = ph->p_memsz;
 618                 } else if (ph->p_type == PT_GNU_RELRO) {
 619                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 620                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 621                 } else if (ph->p_type == PT_GNU_STACK) {
 622                         if (!runtime && ph->p_memsz > __default_stacksize) {
 623                                 __default_stacksize =
 624                                         ph->p_memsz < DEFAULT_STACK_MAX ?
 625                                         ph->p_memsz : DEFAULT_STACK_MAX;
 626                         }
 627                 }
 628                 if (ph->p_type != PT_LOAD) continue;
 629                 nsegs++;
 630                 if (ph->p_vaddr < addr_min) {
 631                         addr_min = ph->p_vaddr;
 632                         off_start = ph->p_offset;
 633                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 634                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 635                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 636                 }
 637                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 638                         addr_max = ph->p_vaddr+ph->p_memsz;
 639                 }
 640         }
 641         if (!dyn) goto noexec;
 642         if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
 643                 dso->loadmap = calloc(1, sizeof *dso->loadmap
 644                         + nsegs * sizeof *dso->loadmap->segs);
 645                 if (!dso->loadmap) goto error;
 646                 dso->loadmap->nsegs = nsegs;
 647                 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
 648                         if (ph->p_type != PT_LOAD) continue;
 649                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 650                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 651                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 652                         map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
 653                                 prot, MAP_PRIVATE,
 654                                 fd, ph->p_offset & -PAGE_SIZE);
 655                         if (map == MAP_FAILED) {
 656                                 unmap_library(dso);
 657                                 goto error;
 658                         }
 659                         dso->loadmap->segs[i].addr = (size_t)map +
 660                                 (ph->p_vaddr & PAGE_SIZE-1);
 661                         dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
 662                         dso->loadmap->segs[i].p_memsz = ph->p_memsz;
 663                         i++;
 664                         if (prot & PROT_WRITE) {
 665                                 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
 666                                         + ph->p_filesz;
 667                                 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
 668                                 size_t pgend = brk + ph->p_memsz - ph->p_filesz
 669                                         + PAGE_SIZE-1 & -PAGE_SIZE;
 670                                 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
 671                                         pgend-pgbrk, prot,
 672                                         MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
 673                                         -1, off_start) == MAP_FAILED)
 674                                         goto error;
 675                                 memset(map + brk, 0, pgbrk-brk);
 676                         }
 677                 }
 678                 map = (void *)dso->loadmap->segs[0].addr;
 679                 map_len = 0;
 680                 goto done_mapping;
 681         }
 682         addr_max += PAGE_SIZE-1;
 683         addr_max &= -PAGE_SIZE;
 684         addr_min &= -PAGE_SIZE;
 685         off_start &= -PAGE_SIZE;
 686         map_len = addr_max - addr_min + off_start;
 687         /* The first time, we map too much, possibly even more than
 688          * the length of the file. This is okay because we will not
 689          * use the invalid part; we just need to reserve the right
 690          * amount of virtual address space to map over later. */
 691         map = DL_NOMMU_SUPPORT
 692                 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
 693                         MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
 694                 : mmap((void *)addr_min, map_len, prot,
 695                         MAP_PRIVATE, fd, off_start);
 696         if (map==MAP_FAILED) goto error;
 697         dso->map = map;
 698         dso->map_len = map_len;
 699         /* If the loaded file is not relocatable and the requested address is
 700          * not available, then the load operation must fail. */
 701         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 702                 errno = EBUSY;
 703                 goto error;
 704         }
 705         base = map - addr_min;
 706         dso->phdr = 0;
 707         dso->phnum = 0;
 708         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 709                 if (ph->p_type != PT_LOAD) continue;
 710                 /* Check if the programs headers are in this load segment, and
 711                  * if so, record the address for use by dl_iterate_phdr. */
 712                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 713                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 714                         dso->phdr = (void *)(base + ph->p_vaddr
 715                                 + (eh->e_phoff-ph->p_offset));
 716                         dso->phnum = eh->e_phnum;
 717                         dso->phentsize = eh->e_phentsize;
 718                 }
 719                 this_min = ph->p_vaddr & -PAGE_SIZE;
 720                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 721                 off_start = ph->p_offset & -PAGE_SIZE;
 722                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 723                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 724                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 725                 /* Reuse the existing mapping for the lowest-address LOAD */
 726                 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
 727                         if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 728                                 goto error;
 729                 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
 730                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 731                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 732                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 733                         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)
 734                                 goto error;
 735                 }
 736         }
 737         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 738                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 739                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
 740                             && errno != ENOSYS)
 741                                 goto error;
 742                         break;
 743                 }
 744 done_mapping:
 745         dso->base = base;
 746         dso->dynv = laddr(dso, dyn);
 747         if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
 748         free(allocated_buf);
 749         return map;
 750 noexec:
 751         errno = ENOEXEC;
 752 error:
 753         if (map!=MAP_FAILED) unmap_library(dso);
 754         free(allocated_buf);
 755         return 0;
 756 }
 757
 758 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 759 {
 760         size_t l;
 761         int fd;
 762         for (;;) {
 763                 s += strspn(s, ":\n");
 764                 l = strcspn(s, ":\n");
 765                 if (l-1 >= INT_MAX) return -1;
 766                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
 767                         if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 768                         switch (errno) {
 769                         case ENOENT:
 770                         case ENOTDIR:
 771                         case EACCES:
 772                         case ENAMETOOLONG:
 773                                 break;
 774                         default:
 775                                 /* Any negative value but -1 will inhibit
 776                                  * futher path search. */
 777                                 return -2;
 778                         }
 779                 }
 780                 s += l;
 781         }
 782 }
 783
 784 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 785 {
 786         size_t n, l;
 787         const char *s, *t, *origin;
 788         char *d;
 789         if (p->rpath || !p->rpath_orig) return 0;
 790         if (!strchr(p->rpath_orig, '$')) {
 791                 p->rpath = p->rpath_orig;
 792                 return 0;
 793         }
 794         n = 0;
 795         s = p->rpath_orig;
 796         while ((t=strchr(s, '$'))) {
 797                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 798                         return 0;
 799                 s = t+1;
 800                 n++;
 801         }
 802         if (n > SSIZE_MAX/PATH_MAX) return 0;
 803
 804         if (p->kernel_mapped) {
 805                 /* $ORIGIN searches cannot be performed for the main program
 806                  * when it is suid/sgid/AT_SECURE. This is because the
 807                  * pathname is under the control of the caller of execve.
 808                  * For libraries, however, $ORIGIN can be processed safely
 809                  * since the library's pathname came from a trusted source
 810                  * (either system paths or a call to dlopen). */
 811                 if (libc.secure)
 812                         return 0;
 813                 l = readlink("/proc/self/exe", buf, buf_size);
 814                 if (l == -1) switch (errno) {
 815                 case ENOENT:
 816                 case ENOTDIR:
 817                 case EACCES:
 818                         break;
 819                 default:
 820                         return -1;
 821                 }
 822                 if (l >= buf_size)
 823                         return 0;
 824                 buf[l] = 0;
 825                 origin = buf;
 826         } else {
 827                 origin = p->name;
 828         }
 829         t = strrchr(origin, '/');
 830         if (t) {
 831                 l = t-origin;
 832         } else {
 833                 /* Normally p->name will always be an absolute or relative
 834                  * pathname containing at least one '/' character, but in the
 835                  * case where ldso was invoked as a command to execute a
 836                  * program in the working directory, app.name may not. Fix. */
 837                 origin = ".";
 838                 l = 1;
 839         }
 840         /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
 841         if (libc.secure && *origin != '/')
 842                 return 0;
 843         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 844         if (!p->rpath) return -1;
 845
 846         d = p->rpath;
 847         s = p->rpath_orig;
 848         while ((t=strchr(s, '$'))) {
 849                 memcpy(d, s, t-s);
 850                 d += t-s;
 851                 memcpy(d, origin, l);
 852                 d += l;
 853                 /* It was determined previously that the '$' is followed
 854                  * either by "ORIGIN" or "{ORIGIN}". */
 855                 s = t + 7 + 2*(t[1]=='{');
 856         }
 857         strcpy(d, s);
 858         return 0;
 859 }
 860
 861 static void decode_dyn(struct dso *p)
 862 {
 863         size_t dyn[DYN_CNT];
 864         decode_vec(p->dynv, dyn, DYN_CNT);
 865         p->syms = laddr(p, dyn[DT_SYMTAB]);
 866         p->strings = laddr(p, dyn[DT_STRTAB]);
 867         if (dyn[0]&(1<<DT_HASH))
 868                 p->hashtab = laddr(p, dyn[DT_HASH]);
 869         if (dyn[0]&(1<<DT_RPATH))
 870                 p->rpath_orig = p->strings + dyn[DT_RPATH];
 871         if (dyn[0]&(1<<DT_RUNPATH))
 872                 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
 873         if (dyn[0]&(1<<DT_PLTGOT))
 874                 p->got = laddr(p, dyn[DT_PLTGOT]);
 875         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 876                 p->ghashtab = laddr(p, *dyn);
 877         if (search_vec(p->dynv, dyn, DT_VERSYM))
 878                 p->versym = laddr(p, *dyn);
 879 }
 880
 881 static size_t count_syms(struct dso *p)
 882 {
 883         if (p->hashtab) return p->hashtab[1];
 884
 885         size_t nsym, i;
 886         uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
 887         uint32_t *hashval;
 888         for (i = nsym = 0; i < p->ghashtab[0]; i++) {
 889                 if (buckets[i] > nsym)
 890                         nsym = buckets[i];
 891         }
 892         if (nsym) {
 893                 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
 894                 do nsym++;
 895                 while (!(*hashval++ & 1));
 896         }
 897         return nsym;
 898 }
 899
 900 static void *dl_mmap(size_t n)
 901 {
 902         void *p;
 903         int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
 904 #ifdef SYS_mmap2
 905         p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
 906 #else
 907         p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
 908 #endif
 909         return p == MAP_FAILED ? 0 : p;
 910 }
 911
 912 static void makefuncdescs(struct dso *p)
 913 {
 914         static int self_done;
 915         size_t nsym = count_syms(p);
 916         size_t i, size = nsym * sizeof(*p->funcdescs);
 917
 918         if (!self_done) {
 919                 p->funcdescs = dl_mmap(size);
 920                 self_done = 1;
 921         } else {
 922                 p->funcdescs = malloc(size);
 923         }
 924         if (!p->funcdescs) {
 925                 if (!runtime) a_crash();
 926                 error("Error allocating function descriptors for %s", p->name);
 927                 longjmp(*rtld_fail, 1);
 928         }
 929         for (i=0; i<nsym; i++) {
 930                 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
 931                         p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
 932                         p->funcdescs[i].got = p->got;
 933                 } else {
 934                         p->funcdescs[i].addr = 0;
 935                         p->funcdescs[i].got = 0;
 936                 }
 937         }
 938 }
 939
 940 static struct dso *load_library(const char *name, struct dso *needed_by)
 941 {
 942         char buf[2*NAME_MAX+2];
 943         const char *pathname;
 944         unsigned char *map;
 945         struct dso *p, temp_dso = {0};
 946         int fd;
 947         struct stat st;
 948         size_t alloc_size;
 949         int n_th = 0;
 950         int is_self = 0;
 951
 952         if (!*name) {
 953                 errno = EINVAL;
 954                 return 0;
 955         }
 956
 957         /* Catch and block attempts to reload the implementation itself */
 958         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 959                 static const char reserved[] =
 960                         "c.pthread.rt.m.dl.util.xnet.";
 961                 const char *rp, *next;
 962                 for (rp=reserved; *rp; rp=next) {
 963                         next = strchr(rp, '.') + 1;
 964                         if (strncmp(name+3, rp, next-rp) == 0)
 965                                 break;
 966                 }
 967                 if (*rp) {
 968                         if (ldd_mode) {
 969                                 /* Track which names have been resolved
 970                                  * and only report each one once. */
 971                                 static unsigned reported;
 972                                 unsigned mask = 1U<<(rp-reserved);
 973                                 if (!(reported & mask)) {
 974                                         reported |= mask;
 975                                         dprintf(1, "\t%s => %s (%p)\n",
 976                                                 name, ldso.name,
 977                                                 ldso.base);
 978                                 }
 979                         }
 980                         is_self = 1;
 981                 }
 982         }
 983         if (!strcmp(name, ldso.name)) is_self = 1;
 984         if (is_self) {
 985                 if (!ldso.prev) {
 986                         tail->next = &ldso;
 987                         ldso.prev = tail;
 988                         tail = &ldso;
 989                 }
 990                 return &ldso;
 991         }
 992         if (strchr(name, '/')) {
 993                 pathname = name;
 994                 fd = open(name, O_RDONLY|O_CLOEXEC);
 995         } else {
 996                 /* Search for the name to see if it's already loaded */
 997                 for (p=head->next; p; p=p->next) {
 998                         if (p->shortname && !strcmp(p->shortname, name)) {
 999                                 return p;
1000                         }
1001                 }
1002                 if (strlen(name) > NAME_MAX) return 0;
1003                 fd = -1;
1004                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1005                 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1006                         if (fixup_rpath(p, buf, sizeof buf) < 0)
1007                                 fd = -2; /* Inhibit further search. */
1008                         if (p->rpath)
1009                                 fd = path_open(name, p->rpath, buf, sizeof buf);
1010                 }
1011                 if (fd == -1) {
1012                         if (!sys_path) {
1013                                 char *prefix = 0;
1014                                 size_t prefix_len;
1015                                 if (ldso.name[0]=='/') {
1016                                         char *s, *t, *z;
1017                                         for (s=t=z=ldso.name; *s; s++)
1018                                                 if (*s=='/') z=t, t=s;
1019                                         prefix_len = z-ldso.name;
1020                                         if (prefix_len < PATH_MAX)
1021                                                 prefix = ldso.name;
1022                                 }
1023                                 if (!prefix) {
1024                                         prefix = "";
1025                                         prefix_len = 0;
1026                                 }
1027                                 char etc_ldso_path[prefix_len + 1
1028                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1029                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1030                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1031                                         (int)prefix_len, prefix);
1032                                 FILE *f = fopen(etc_ldso_path, "rbe");
1033                                 if (f) {
1034                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1035                                                 free(sys_path);
1036                                                 sys_path = "";
1037                                         }
1038                                         fclose(f);
1039                                 } else if (errno != ENOENT) {
1040                                         sys_path = "";
1041                                 }
1042                         }
1043                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1044                         fd = path_open(name, sys_path, buf, sizeof buf);
1045                 }
1046                 pathname = buf;
1047         }
1048         if (fd < 0) return 0;
1049         if (fstat(fd, &st) < 0) {
1050                 close(fd);
1051                 return 0;
1052         }
1053         for (p=head->next; p; p=p->next) {
1054                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1055                         /* If this library was previously loaded with a
1056                          * pathname but a search found the same inode,
1057                          * setup its shortname so it can be found by name. */
1058                         if (!p->shortname && pathname != name)
1059                                 p->shortname = strrchr(p->name, '/')+1;
1060                         close(fd);
1061                         return p;
1062                 }
1063         }
1064         map = noload ? 0 : map_library(fd, &temp_dso);
1065         close(fd);
1066         if (!map) return 0;
1067
1068         /* Avoid the danger of getting two versions of libc mapped into the
1069          * same process when an absolute pathname was used. The symbols
1070          * checked are chosen to catch both musl and glibc, and to avoid
1071          * false positives from interposition-hack libraries. */
1072         decode_dyn(&temp_dso);
1073         if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1074             find_sym(&temp_dso, "stdin", 1).sym) {
1075                 unmap_library(&temp_dso);
1076                 return load_library("libc.so", needed_by);
1077         }
1078         /* Past this point, if we haven't reached runtime yet, ldso has
1079          * committed either to use the mapped library or to abort execution.
1080          * Unmapping is not possible, so we can safely reclaim gaps. */
1081         if (!runtime) reclaim_gaps(&temp_dso);
1082
1083         /* Allocate storage for the new DSO. When there is TLS, this
1084          * storage must include a reservation for all pre-existing
1085          * threads to obtain copies of both the new TLS, and an
1086          * extended DTV capable of storing an additional slot for
1087          * the newly-loaded DSO. */
1088         alloc_size = sizeof *p + strlen(pathname) + 1;
1089         if (runtime && temp_dso.tls.image) {
1090                 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1091                         + sizeof(void *) * (tls_cnt+3);
1092                 n_th = libc.threads_minus_1 + 1;
1093                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1094                 else alloc_size += n_th * per_th;
1095         }
1096         p = calloc(1, alloc_size);
1097         if (!p) {
1098                 unmap_library(&temp_dso);
1099                 return 0;
1100         }
1101         memcpy(p, &temp_dso, sizeof temp_dso);
1102         p->dev = st.st_dev;
1103         p->ino = st.st_ino;
1104         p->needed_by = needed_by;
1105         p->name = p->buf;
1106         strcpy(p->name, pathname);
1107         /* Add a shortname only if name arg was not an explicit pathname. */
1108         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1109         if (p->tls.image) {
1110                 p->tls_id = ++tls_cnt;
1111                 tls_align = MAXP2(tls_align, p->tls.align);
1112 #ifdef TLS_ABOVE_TP
1113                 p->tls.offset = tls_offset + ( (tls_align-1) &
1114                         -(tls_offset + (uintptr_t)p->tls.image) );
1115                 tls_offset += p->tls.size;
1116 #else
1117                 tls_offset += p->tls.size + p->tls.align - 1;
1118                 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1119                         & (p->tls.align-1);
1120                 p->tls.offset = tls_offset;
1121 #endif
1122                 p->new_dtv = (void *)(-sizeof(size_t) &
1123                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1124                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1125                 if (tls_tail) tls_tail->next = &p->tls;
1126                 else libc.tls_head = &p->tls;
1127                 tls_tail = &p->tls;
1128         }
1129
1130         tail->next = p;
1131         p->prev = tail;
1132         tail = p;
1133
1134         if (DL_FDPIC) makefuncdescs(p);
1135
1136         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1137
1138         return p;
1139 }
1140
1141 static void load_deps(struct dso *p)
1142 {
1143         size_t i, ndeps=0;
1144         struct dso ***deps = &p->deps, **tmp, *dep;
1145         for (; p; p=p->next) {
1146                 for (i=0; p->dynv[i]; i+=2) {
1147                         if (p->dynv[i] != DT_NEEDED) continue;
1148                         dep = load_library(p->strings + p->dynv[i+1], p);
1149                         if (!dep) {
1150                                 error("Error loading shared library %s: %m (needed by %s)",
1151                                         p->strings + p->dynv[i+1], p->name);
1152                                 if (runtime) longjmp(*rtld_fail, 1);
1153                                 continue;
1154                         }
1155                         if (runtime) {
1156                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1157                                 if (!tmp) longjmp(*rtld_fail, 1);
1158                                 tmp[ndeps++] = dep;
1159                                 tmp[ndeps] = 0;
1160                                 *deps = tmp;
1161                         }
1162                 }
1163         }
1164         if (!*deps) *deps = (struct dso **)&nodeps_dummy;
1165 }
1166
1167 static void load_preload(char *s)
1168 {
1169         int tmp;
1170         char *z;
1171         for (z=s; *z; s=z) {
1172                 for (   ; *s && (isspace(*s) || *s==':'); s++);
1173                 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1174                 tmp = *z;
1175                 *z = 0;
1176                 load_library(s, 0);
1177                 *z = tmp;
1178         }
1179 }
1180
1181 static void add_syms(struct dso *p)
1182 {
1183         if (!p->syms_next && syms_tail != p) {
1184                 syms_tail->syms_next = p;
1185                 syms_tail = p;
1186         }
1187 }
1188
1189 static void revert_syms(struct dso *old_tail)
1190 {
1191         struct dso *p, *next;
1192         /* Chop off the tail of the list of dsos that participate in
1193          * the global symbol table, reverting them to RTLD_LOCAL. */
1194         for (p=old_tail; p; p=next) {
1195                 next = p->syms_next;
1196                 p->syms_next = 0;
1197         }
1198         syms_tail = old_tail;
1199 }
1200
1201 static void do_mips_relocs(struct dso *p, size_t *got)
1202 {
1203         size_t i, j, rel[2];
1204         unsigned char *base = p->base;
1205         i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1206         if (p==&ldso) {
1207                 got += i;
1208         } else {
1209                 while (i--) *got++ += (size_t)base;
1210         }
1211         j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1212         i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1213         Sym *sym = p->syms + j;
1214         rel[0] = (unsigned char *)got - base;
1215         for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1216                 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1217                 do_relocs(p, rel, sizeof rel, 2);
1218         }
1219 }
1220
1221 static void reloc_all(struct dso *p)
1222 {
1223         size_t dyn[DYN_CNT];
1224         for (; p; p=p->next) {
1225                 if (p->relocated) continue;
1226                 decode_vec(p->dynv, dyn, DYN_CNT);
1227                 if (NEED_MIPS_GOT_RELOCS)
1228                         do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1229                 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1230                         2+(dyn[DT_PLTREL]==DT_RELA));
1231                 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1232                 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1233
1234                 if (head != &ldso && p->relro_start != p->relro_end &&
1235                     mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1236                     && errno != ENOSYS) {
1237                         error("Error relocating %s: RELRO protection failed: %m",
1238                                 p->name);
1239                         if (runtime) longjmp(*rtld_fail, 1);
1240                 }
1241
1242                 p->relocated = 1;
1243         }
1244 }
1245
1246 static void kernel_mapped_dso(struct dso *p)
1247 {
1248         size_t min_addr = -1, max_addr = 0, cnt;
1249         Phdr *ph = p->phdr;
1250         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1251                 if (ph->p_type == PT_DYNAMIC) {
1252                         p->dynv = laddr(p, ph->p_vaddr);
1253                 } else if (ph->p_type == PT_GNU_RELRO) {
1254                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1255                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1256                 } else if (ph->p_type == PT_GNU_STACK) {
1257                         if (!runtime && ph->p_memsz > __default_stacksize) {
1258                                 __default_stacksize =
1259                                         ph->p_memsz < DEFAULT_STACK_MAX ?
1260                                         ph->p_memsz : DEFAULT_STACK_MAX;
1261                         }
1262                 }
1263                 if (ph->p_type != PT_LOAD) continue;
1264                 if (ph->p_vaddr < min_addr)
1265                         min_addr = ph->p_vaddr;
1266                 if (ph->p_vaddr+ph->p_memsz > max_addr)
1267                         max_addr = ph->p_vaddr+ph->p_memsz;
1268         }
1269         min_addr &= -PAGE_SIZE;
1270         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1271         p->map = p->base + min_addr;
1272         p->map_len = max_addr - min_addr;
1273         p->kernel_mapped = 1;
1274 }
1275
1276 void __libc_exit_fini()
1277 {
1278         struct dso *p;
1279         size_t dyn[DYN_CNT];
1280         for (p=fini_head; p; p=p->fini_next) {
1281                 if (!p->constructed) continue;
1282                 decode_vec(p->dynv, dyn, DYN_CNT);
1283                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1284                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1285                         size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1286                         while (n--) ((void (*)(void))*--fn)();
1287                 }
1288 #ifndef NO_LEGACY_INITFINI
1289                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1290                         fpaddr(p, dyn[DT_FINI])();
1291 #endif
1292         }
1293 }
1294
1295 static void do_init_fini(struct dso *p)
1296 {
1297         size_t dyn[DYN_CNT];
1298         int need_locking = libc.threads_minus_1;
1299         /* Allow recursive calls that arise when a library calls
1300          * dlopen from one of its constructors, but block any
1301          * other threads until all ctors have finished. */
1302         if (need_locking) pthread_mutex_lock(&init_fini_lock);
1303         for (; p; p=p->prev) {
1304                 if (p->constructed) continue;
1305                 p->constructed = 1;
1306                 decode_vec(p->dynv, dyn, DYN_CNT);
1307                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1308                         p->fini_next = fini_head;
1309                         fini_head = p;
1310                 }
1311 #ifndef NO_LEGACY_INITFINI
1312                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1313                         fpaddr(p, dyn[DT_INIT])();
1314 #endif
1315                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1316                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1317                         size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1318                         while (n--) ((void (*)(void))*fn++)();
1319                 }
1320                 if (!need_locking && libc.threads_minus_1) {
1321                         need_locking = 1;
1322                         pthread_mutex_lock(&init_fini_lock);
1323                 }
1324         }
1325         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1326 }
1327
1328 void __libc_start_init(void)
1329 {
1330         do_init_fini(tail);
1331 }
1332
1333 static void dl_debug_state(void)
1334 {
1335 }
1336
1337 weak_alias(dl_debug_state, _dl_debug_state);
1338
1339 void __init_tls(size_t *auxv)
1340 {
1341 }
1342
1343 static void update_tls_size()
1344 {
1345         libc.tls_cnt = tls_cnt;
1346         libc.tls_align = tls_align;
1347         libc.tls_size = ALIGN(
1348                 (1+tls_cnt) * sizeof(void *) +
1349                 tls_offset +
1350                 sizeof(struct pthread) +
1351                 tls_align * 2,
1352         tls_align);
1353 }
1354
1355 static void install_new_tls(void)
1356 {
1357         sigset_t set;
1358         pthread_t self = __pthread_self(), td;
1359         uintptr_t (*newdtv)[tls_cnt+1] = (void *)tail->new_dtv;
1360         struct dso *p;
1361         size_t i, j;
1362         size_t old_cnt = self->dtv[0];
1363
1364         __block_app_sigs(&set);
1365         __tl_lock();
1366         /* Copy existing dtv contents from all existing threads. */
1367         for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1368                 memcpy(newdtv+i, td->dtv,
1369                         (old_cnt+1)*sizeof(uintptr_t));
1370                 newdtv[i][0] = tls_cnt;
1371         }
1372         /* Install new dtls into the enlarged, uninstalled dtv copies. */
1373         for (p=head; ; p=p->next) {
1374                 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1375                 unsigned char *mem = p->new_tls;
1376                 for (j=0; j<i; j++) {
1377                         unsigned char *new = mem;
1378                         new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1379                                 & (p->tls.align-1);
1380                         memcpy(new, p->tls.image, p->tls.len);
1381                         newdtv[j][p->tls_id] =
1382                                 (uintptr_t)new + DTP_OFFSET;
1383                         mem += p->tls.size + p->tls.align;
1384                 }
1385                 if (p->tls_id == tls_cnt) break;
1386         }
1387
1388         /* Broadcast barrier to ensure contents of new dtv is visible
1389          * if the new dtv pointer is. The __membarrier function has a
1390          * fallback emulation using signals for kernels that lack the
1391          * feature at the syscall level. */
1392
1393         __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1394
1395         /* Install new dtv for each thread. */
1396         for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1397                 td->dtv = td->dtv_copy = newdtv[j];
1398         }
1399
1400         __tl_unlock();
1401         __restore_sigs(&set);
1402 }
1403
1404 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1405  * following stage 2 and stage 3 functions via primitive symbolic lookup
1406  * since it does not have access to their addresses to begin with. */
1407
1408 /* Stage 2 of the dynamic linker is called after relative relocations
1409  * have been processed. It can make function calls to static functions
1410  * and access string literals and static data, but cannot use extern
1411  * symbols. Its job is to perform symbolic relocations on the dynamic
1412  * linker itself, but some of the relocations performed may need to be
1413  * replaced later due to copy relocations in the main program. */
1414
1415 hidden void __dls2(unsigned char *base, size_t *sp)
1416 {
1417         if (DL_FDPIC) {
1418                 void *p1 = (void *)sp[-2];
1419                 void *p2 = (void *)sp[-1];
1420                 if (!p1) {
1421                         size_t *auxv, aux[AUX_CNT];
1422                         for (auxv=sp+1+*sp+1; *auxv; auxv++);
1423                         auxv++;
1424                         decode_vec(auxv, aux, AUX_CNT);
1425                         if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1426                         else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1427                 }
1428                 app_loadmap = p2 ? p1 : 0;
1429                 ldso.loadmap = p2 ? p2 : p1;
1430                 ldso.base = laddr(&ldso, 0);
1431         } else {
1432                 ldso.base = base;
1433         }
1434         Ehdr *ehdr = (void *)ldso.base;
1435         ldso.name = ldso.shortname = "libc.so";
1436         ldso.phnum = ehdr->e_phnum;
1437         ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1438         ldso.phentsize = ehdr->e_phentsize;
1439         kernel_mapped_dso(&ldso);
1440         decode_dyn(&ldso);
1441
1442         if (DL_FDPIC) makefuncdescs(&ldso);
1443
1444         /* Prepare storage for to save clobbered REL addends so they
1445          * can be reused in stage 3. There should be very few. If
1446          * something goes wrong and there are a huge number, abort
1447          * instead of risking stack overflow. */
1448         size_t dyn[DYN_CNT];
1449         decode_vec(ldso.dynv, dyn, DYN_CNT);
1450         size_t *rel = laddr(&ldso, dyn[DT_REL]);
1451         size_t rel_size = dyn[DT_RELSZ];
1452         size_t symbolic_rel_cnt = 0;
1453         apply_addends_to = rel;
1454         for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1455                 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1456         if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1457         size_t addends[symbolic_rel_cnt+1];
1458         saved_addends = addends;
1459
1460         head = &ldso;
1461         reloc_all(&ldso);
1462
1463         ldso.relocated = 0;
1464
1465         /* Call dynamic linker stage-2b, __dls2b, looking it up
1466          * symbolically as a barrier against moving the address
1467          * load across the above relocation processing. */
1468         struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1469         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp);
1470         else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp);
1471 }
1472
1473 /* Stage 2b sets up a valid thread pointer, which requires relocations
1474  * completed in stage 2, and on which stage 3 is permitted to depend.
1475  * This is done as a separate stage, with symbolic lookup as a barrier,
1476  * so that loads of the thread pointer and &errno can be pure/const and
1477  * thereby hoistable. */
1478
1479 _Noreturn void __dls2b(size_t *sp)
1480 {
1481         /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1482          * use during dynamic linking. If possible it will also serve as the
1483          * thread pointer at runtime. */
1484         libc.tls_size = sizeof builtin_tls;
1485         libc.tls_align = tls_align;
1486         if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1487                 a_crash();
1488         }
1489
1490         struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1491         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1492         else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1493 }
1494
1495 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1496  * fully functional. Its job is to load (if not already loaded) and
1497  * process dependencies and relocations for the main application and
1498  * transfer control to its entry point. */
1499
1500 _Noreturn void __dls3(size_t *sp)
1501 {
1502         static struct dso app, vdso;
1503         size_t aux[AUX_CNT], *auxv;
1504         size_t i;
1505         char *env_preload=0;
1506         char *replace_argv0=0;
1507         size_t vdso_base;
1508         int argc = *sp;
1509         char **argv = (void *)(sp+1);
1510         char **argv_orig = argv;
1511         char **envp = argv+argc+1;
1512
1513         /* Find aux vector just past environ[] and use it to initialize
1514          * global data that may be needed before we can make syscalls. */
1515         __environ = envp;
1516         for (i=argc+1; argv[i]; i++);
1517         libc.auxv = auxv = (void *)(argv+i+1);
1518         decode_vec(auxv, aux, AUX_CNT);
1519         __hwcap = aux[AT_HWCAP];
1520         libc.page_size = aux[AT_PAGESZ];
1521         libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1522                 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1523
1524         /* Only trust user/env if kernel says we're not suid/sgid */
1525         if (!libc.secure) {
1526                 env_path = getenv("LD_LIBRARY_PATH");
1527                 env_preload = getenv("LD_PRELOAD");
1528         }
1529
1530         /* If the main program was already loaded by the kernel,
1531          * AT_PHDR will point to some location other than the dynamic
1532          * linker's program headers. */
1533         if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1534                 size_t interp_off = 0;
1535                 size_t tls_image = 0;
1536                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1537                 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1538                 app.phnum = aux[AT_PHNUM];
1539                 app.phentsize = aux[AT_PHENT];
1540                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1541                         if (phdr->p_type == PT_PHDR)
1542                                 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1543                         else if (phdr->p_type == PT_INTERP)
1544                                 interp_off = (size_t)phdr->p_vaddr;
1545                         else if (phdr->p_type == PT_TLS) {
1546                                 tls_image = phdr->p_vaddr;
1547                                 app.tls.len = phdr->p_filesz;
1548                                 app.tls.size = phdr->p_memsz;
1549                                 app.tls.align = phdr->p_align;
1550                         }
1551                 }
1552                 if (DL_FDPIC) app.loadmap = app_loadmap;
1553                 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1554                 if (interp_off) ldso.name = laddr(&app, interp_off);
1555                 if ((aux[0] & (1UL<<AT_EXECFN))
1556                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1557                         app.name = (char *)aux[AT_EXECFN];
1558                 else
1559                         app.name = argv[0];
1560                 kernel_mapped_dso(&app);
1561         } else {
1562                 int fd;
1563                 char *ldname = argv[0];
1564                 size_t l = strlen(ldname);
1565                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1566                 argv++;
1567                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1568                         char *opt = argv[0]+2;
1569                         *argv++ = (void *)-1;
1570                         if (!*opt) {
1571                                 break;
1572                         } else if (!memcmp(opt, "list", 5)) {
1573                                 ldd_mode = 1;
1574                         } else if (!memcmp(opt, "library-path", 12)) {
1575                                 if (opt[12]=='=') env_path = opt+13;
1576                                 else if (opt[12]) *argv = 0;
1577                                 else if (*argv) env_path = *argv++;
1578                         } else if (!memcmp(opt, "preload", 7)) {
1579                                 if (opt[7]=='=') env_preload = opt+8;
1580                                 else if (opt[7]) *argv = 0;
1581                                 else if (*argv) env_preload = *argv++;
1582                         } else if (!memcmp(opt, "argv0", 5)) {
1583                                 if (opt[5]=='=') replace_argv0 = opt+6;
1584                                 else if (opt[5]) *argv = 0;
1585                                 else if (*argv) replace_argv0 = *argv++;
1586                         } else {
1587                                 argv[0] = 0;
1588                         }
1589                 }
1590                 argv[-1] = (void *)(argc - (argv-argv_orig));
1591                 if (!argv[0]) {
1592                         dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1593                                 "Version %s\n"
1594                                 "Dynamic Program Loader\n"
1595                                 "Usage: %s [options] [--] pathname%s\n",
1596                                 __libc_version, ldname,
1597                                 ldd_mode ? "" : " [args]");
1598                         _exit(1);
1599                 }
1600                 fd = open(argv[0], O_RDONLY);
1601                 if (fd < 0) {
1602                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1603                         _exit(1);
1604                 }
1605                 Ehdr *ehdr = (void *)map_library(fd, &app);
1606                 if (!ehdr) {
1607                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1608                         _exit(1);
1609                 }
1610                 close(fd);
1611                 ldso.name = ldname;
1612                 app.name = argv[0];
1613                 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1614                 /* Find the name that would have been used for the dynamic
1615                  * linker had ldd not taken its place. */
1616                 if (ldd_mode) {
1617                         for (i=0; i<app.phnum; i++) {
1618                                 if (app.phdr[i].p_type == PT_INTERP)
1619                                         ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1620                         }
1621                         dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1622                 }
1623         }
1624         if (app.tls.size) {
1625                 libc.tls_head = tls_tail = &app.tls;
1626                 app.tls_id = tls_cnt = 1;
1627 #ifdef TLS_ABOVE_TP
1628                 app.tls.offset = GAP_ABOVE_TP;
1629                 app.tls.offset += -GAP_ABOVE_TP & (app.tls.align-1);
1630                 tls_offset = app.tls.offset + app.tls.size
1631                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1632                         & (app.tls.align-1) );
1633 #else
1634                 tls_offset = app.tls.offset = app.tls.size
1635                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1636                         & (app.tls.align-1) );
1637 #endif
1638                 tls_align = MAXP2(tls_align, app.tls.align);
1639         }
1640         decode_dyn(&app);
1641         if (DL_FDPIC) {
1642                 makefuncdescs(&app);
1643                 if (!app.loadmap) {
1644                         app.loadmap = (void *)&app_dummy_loadmap;
1645                         app.loadmap->nsegs = 1;
1646                         app.loadmap->segs[0].addr = (size_t)app.map;
1647                         app.loadmap->segs[0].p_vaddr = (size_t)app.map
1648                                 - (size_t)app.base;
1649                         app.loadmap->segs[0].p_memsz = app.map_len;
1650                 }
1651                 argv[-3] = (void *)app.loadmap;
1652         }
1653
1654         /* Initial dso chain consists only of the app. */
1655         head = tail = syms_tail = &app;
1656
1657         /* Donate unused parts of app and library mapping to malloc */
1658         reclaim_gaps(&app);
1659         reclaim_gaps(&ldso);
1660
1661         /* Load preload/needed libraries, add symbols to global namespace. */
1662         if (env_preload) load_preload(env_preload);
1663         load_deps(&app);
1664         for (struct dso *p=head; p; p=p->next)
1665                 add_syms(p);
1666
1667         /* Attach to vdso, if provided by the kernel, last so that it does
1668          * not become part of the global namespace.  */
1669         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1670                 Ehdr *ehdr = (void *)vdso_base;
1671                 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1672                 vdso.phnum = ehdr->e_phnum;
1673                 vdso.phentsize = ehdr->e_phentsize;
1674                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1675                         if (phdr->p_type == PT_DYNAMIC)
1676                                 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1677                         if (phdr->p_type == PT_LOAD)
1678                                 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1679                 }
1680                 vdso.name = "";
1681                 vdso.shortname = "linux-gate.so.1";
1682                 vdso.relocated = 1;
1683                 decode_dyn(&vdso);
1684                 vdso.prev = tail;
1685                 tail->next = &vdso;
1686                 tail = &vdso;
1687         }
1688
1689         for (i=0; app.dynv[i]; i+=2) {
1690                 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1691                         app.dynv[i+1] = (size_t)&debug;
1692                 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1693                         size_t *ptr = (size_t *) app.dynv[i+1];
1694                         *ptr = (size_t)&debug;
1695                 }
1696         }
1697
1698         /* The main program must be relocated LAST since it may contin
1699          * copy relocations which depend on libraries' relocations. */
1700         reloc_all(app.next);
1701         reloc_all(&app);
1702
1703         update_tls_size();
1704         if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1705                 void *initial_tls = calloc(libc.tls_size, 1);
1706                 if (!initial_tls) {
1707                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1708                                 argv[0], libc.tls_size);
1709                         _exit(127);
1710                 }
1711                 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1712                         a_crash();
1713                 }
1714         } else {
1715                 size_t tmp_tls_size = libc.tls_size;
1716                 pthread_t self = __pthread_self();
1717                 /* Temporarily set the tls size to the full size of
1718                  * builtin_tls so that __copy_tls will use the same layout
1719                  * as it did for before. Then check, just to be safe. */
1720                 libc.tls_size = sizeof builtin_tls;
1721                 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1722                 libc.tls_size = tmp_tls_size;
1723         }
1724         static_tls_cnt = tls_cnt;
1725
1726         if (ldso_fail) _exit(127);
1727         if (ldd_mode) _exit(0);
1728
1729         /* Determine if malloc was interposed by a replacement implementation
1730          * so that calloc and the memalign family can harden against the
1731          * possibility of incomplete replacement. */
1732         if (find_sym(head, "malloc", 1).dso != &ldso)
1733                 __malloc_replaced = 1;
1734
1735         /* Switch to runtime mode: any further failures in the dynamic
1736          * linker are a reportable failure rather than a fatal startup
1737          * error. */
1738         runtime = 1;
1739
1740         debug.ver = 1;
1741         debug.bp = dl_debug_state;
1742         debug.head = head;
1743         debug.base = ldso.base;
1744         debug.state = 0;
1745         _dl_debug_state();
1746
1747         if (replace_argv0) argv[0] = replace_argv0;
1748
1749         errno = 0;
1750
1751         CRTJMP((void *)aux[AT_ENTRY], argv-1);
1752         for(;;);
1753 }
1754
1755 static void prepare_lazy(struct dso *p)
1756 {
1757         size_t dyn[DYN_CNT], n, flags1=0;
1758         decode_vec(p->dynv, dyn, DYN_CNT);
1759         search_vec(p->dynv, &flags1, DT_FLAGS_1);
1760         if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1761                 return;
1762         n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1763         if (NEED_MIPS_GOT_RELOCS) {
1764                 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1765                 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1766                 n += i-j;
1767         }
1768         p->lazy = calloc(n, 3*sizeof(size_t));
1769         if (!p->lazy) {
1770                 error("Error preparing lazy relocation for %s: %m", p->name);
1771                 longjmp(*rtld_fail, 1);
1772         }
1773         p->lazy_next = lazy_head;
1774         lazy_head = p;
1775 }
1776
1777 void *dlopen(const char *file, int mode)
1778 {
1779         struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1780         struct tls_module *orig_tls_tail;
1781         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1782         size_t i;
1783         int cs;
1784         jmp_buf jb;
1785
1786         if (!file) return head;
1787
1788         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1789         pthread_rwlock_wrlock(&lock);
1790         __inhibit_ptc();
1791
1792         p = 0;
1793         orig_tls_tail = tls_tail;
1794         orig_tls_cnt = tls_cnt;
1795         orig_tls_offset = tls_offset;
1796         orig_tls_align = tls_align;
1797         orig_lazy_head = lazy_head;
1798         orig_syms_tail = syms_tail;
1799         orig_tail = tail;
1800         noload = mode & RTLD_NOLOAD;
1801
1802         rtld_fail = &jb;
1803         if (setjmp(*rtld_fail)) {
1804                 /* Clean up anything new that was (partially) loaded */
1805                 revert_syms(orig_syms_tail);
1806                 for (p=orig_tail->next; p; p=next) {
1807                         next = p->next;
1808                         while (p->td_index) {
1809                                 void *tmp = p->td_index->next;
1810                                 free(p->td_index);
1811                                 p->td_index = tmp;
1812                         }
1813                         free(p->funcdescs);
1814                         if (p->rpath != p->rpath_orig)
1815                                 free(p->rpath);
1816                         if (p->deps != &nodeps_dummy)
1817                                 free(p->deps);
1818                         unmap_library(p);
1819                         free(p);
1820                 }
1821                 if (!orig_tls_tail) libc.tls_head = 0;
1822                 tls_tail = orig_tls_tail;
1823                 if (tls_tail) tls_tail->next = 0;
1824                 tls_cnt = orig_tls_cnt;
1825                 tls_offset = orig_tls_offset;
1826                 tls_align = orig_tls_align;
1827                 lazy_head = orig_lazy_head;
1828                 tail = orig_tail;
1829                 tail->next = 0;
1830                 p = 0;
1831                 goto end;
1832         } else p = load_library(file, head);
1833
1834         if (!p) {
1835                 error(noload ?
1836                         "Library %s is not already loaded" :
1837                         "Error loading shared library %s: %m",
1838                         file);
1839                 goto end;
1840         }
1841
1842         /* First load handling */
1843         int first_load = !p->deps;
1844         if (first_load) {
1845                 load_deps(p);
1846                 if (!p->relocated && (mode & RTLD_LAZY)) {
1847                         prepare_lazy(p);
1848                         for (i=0; p->deps[i]; i++)
1849                                 if (!p->deps[i]->relocated)
1850                                         prepare_lazy(p->deps[i]);
1851                 }
1852         }
1853         if (first_load || (mode & RTLD_GLOBAL)) {
1854                 /* Make new symbols global, at least temporarily, so we can do
1855                  * relocations. If not RTLD_GLOBAL, this is reverted below. */
1856                 add_syms(p);
1857                 for (i=0; p->deps[i]; i++)
1858                         add_syms(p->deps[i]);
1859         }
1860         if (first_load) {
1861                 reloc_all(p);
1862         }
1863
1864         /* If RTLD_GLOBAL was not specified, undo any new additions
1865          * to the global symbol table. This is a nop if the library was
1866          * previously loaded and already global. */
1867         if (!(mode & RTLD_GLOBAL))
1868                 revert_syms(orig_syms_tail);
1869
1870         /* Processing of deferred lazy relocations must not happen until
1871          * the new libraries are committed; otherwise we could end up with
1872          * relocations resolved to symbol definitions that get removed. */
1873         redo_lazy_relocs();
1874
1875         update_tls_size();
1876         if (tls_cnt != orig_tls_cnt)
1877                 install_new_tls();
1878         _dl_debug_state();
1879         orig_tail = tail;
1880 end:
1881         __release_ptc();
1882         if (p) gencnt++;
1883         pthread_rwlock_unlock(&lock);
1884         if (p) do_init_fini(orig_tail);
1885         pthread_setcancelstate(cs, 0);
1886         return p;
1887 }
1888
1889 hidden int __dl_invalid_handle(void *h)
1890 {
1891         struct dso *p;
1892         for (p=head; p; p=p->next) if (h==p) return 0;
1893         error("Invalid library handle %p", (void *)h);
1894         return 1;
1895 }
1896
1897 static void *addr2dso(size_t a)
1898 {
1899         struct dso *p;
1900         size_t i;
1901         if (DL_FDPIC) for (p=head; p; p=p->next) {
1902                 i = count_syms(p);
1903                 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1904                         return p;
1905         }
1906         for (p=head; p; p=p->next) {
1907                 if (DL_FDPIC && p->loadmap) {
1908                         for (i=0; i<p->loadmap->nsegs; i++) {
1909                                 if (a-p->loadmap->segs[i].p_vaddr
1910                                     < p->loadmap->segs[i].p_memsz)
1911                                         return p;
1912                         }
1913                 } else {
1914                         Phdr *ph = p->phdr;
1915                         size_t phcnt = p->phnum;
1916                         size_t entsz = p->phentsize;
1917                         size_t base = (size_t)p->base;
1918                         for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
1919                                 if (ph->p_type != PT_LOAD) continue;
1920                                 if (a-base-ph->p_vaddr < ph->p_memsz)
1921                                         return p;
1922                         }
1923                         if (a-(size_t)p->map < p->map_len)
1924                                 return 0;
1925                 }
1926         }
1927         return 0;
1928 }
1929
1930 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1931 {
1932         size_t i;
1933         uint32_t h = 0, gh = 0, *ght;
1934         Sym *sym;
1935         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1936                 if (p == RTLD_DEFAULT) {
1937                         p = head;
1938                 } else if (p == RTLD_NEXT) {
1939                         p = addr2dso((size_t)ra);
1940                         if (!p) p=head;
1941                         p = p->next;
1942                 }
1943                 struct symdef def = find_sym(p, s, 0);
1944                 if (!def.sym) goto failed;
1945                 if ((def.sym->st_info&0xf) == STT_TLS)
1946                         return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
1947                 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1948                         return def.dso->funcdescs + (def.sym - def.dso->syms);
1949                 return laddr(def.dso, def.sym->st_value);
1950         }
1951         if (__dl_invalid_handle(p))
1952                 return 0;
1953         if ((ght = p->ghashtab)) {
1954                 gh = gnu_hash(s);
1955                 sym = gnu_lookup(gh, ght, p, s);
1956         } else {
1957                 h = sysv_hash(s);
1958                 sym = sysv_lookup(s, h, p);
1959         }
1960         if (sym && (sym->st_info&0xf) == STT_TLS)
1961                 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value-DTP_OFFSET});
1962         if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1963                 return p->funcdescs + (sym - p->syms);
1964         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1965                 return laddr(p, sym->st_value);
1966         for (i=0; p->deps[i]; i++) {
1967                 if ((ght = p->deps[i]->ghashtab)) {
1968                         if (!gh) gh = gnu_hash(s);
1969                         sym = gnu_lookup(gh, ght, p->deps[i], s);
1970                 } else {
1971                         if (!h) h = sysv_hash(s);
1972                         sym = sysv_lookup(s, h, p->deps[i]);
1973                 }
1974                 if (sym && (sym->st_info&0xf) == STT_TLS)
1975                         return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value-DTP_OFFSET});
1976                 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1977                         return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1978                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1979                         return laddr(p->deps[i], sym->st_value);
1980         }
1981 failed:
1982         error("Symbol not found: %s", s);
1983         return 0;
1984 }
1985
1986 int dladdr(const void *addr_arg, Dl_info *info)
1987 {
1988         size_t addr = (size_t)addr_arg;
1989         struct dso *p;
1990         Sym *sym, *bestsym;
1991         uint32_t nsym;
1992         char *strings;
1993         size_t best = 0;
1994         size_t besterr = -1;
1995
1996         pthread_rwlock_rdlock(&lock);
1997         p = addr2dso(addr);
1998         pthread_rwlock_unlock(&lock);
1999
2000         if (!p) return 0;
2001
2002         sym = p->syms;
2003         strings = p->strings;
2004         nsym = count_syms(p);
2005
2006         if (DL_FDPIC) {
2007                 size_t idx = (addr-(size_t)p->funcdescs)
2008                         / sizeof(*p->funcdescs);
2009                 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2010                         best = (size_t)(p->funcdescs + idx);
2011                         bestsym = sym + idx;
2012                         besterr = 0;
2013                 }
2014         }
2015
2016         if (!best) for (; nsym; nsym--, sym++) {
2017                 if (sym->st_value
2018                  && (1<<(sym->st_info&0xf) & OK_TYPES)
2019                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
2020                         size_t symaddr = (size_t)laddr(p, sym->st_value);
2021                         if (symaddr > addr || symaddr <= best)
2022                                 continue;
2023                         best = symaddr;
2024                         bestsym = sym;
2025                         besterr = addr - symaddr;
2026                         if (addr == symaddr)
2027                                 break;
2028                 }
2029         }
2030
2031         if (bestsym && besterr > bestsym->st_size-1) {
2032                 best = 0;
2033                 bestsym = 0;
2034         }
2035
2036         info->dli_fname = p->name;
2037         info->dli_fbase = p->map;
2038
2039         if (!best) {
2040                 info->dli_sname = 0;
2041                 info->dli_saddr = 0;
2042                 return 1;
2043         }
2044
2045         if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2046                 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2047         info->dli_sname = strings + bestsym->st_name;
2048         info->dli_saddr = (void *)best;
2049
2050         return 1;
2051 }
2052
2053 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2054 {
2055         void *res;
2056         pthread_rwlock_rdlock(&lock);
2057         res = do_dlsym(p, s, ra);
2058         pthread_rwlock_unlock(&lock);
2059         return res;
2060 }
2061
2062 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2063 {
2064         struct dso *current;
2065         struct dl_phdr_info info;
2066         int ret = 0;
2067         for(current = head; current;) {
2068                 info.dlpi_addr      = (uintptr_t)current->base;
2069                 info.dlpi_name      = current->name;
2070                 info.dlpi_phdr      = current->phdr;
2071                 info.dlpi_phnum     = current->phnum;
2072                 info.dlpi_adds      = gencnt;
2073                 info.dlpi_subs      = 0;
2074                 info.dlpi_tls_modid = current->tls_id;
2075                 info.dlpi_tls_data  = current->tls.image;
2076
2077                 ret = (callback)(&info, sizeof (info), data);
2078
2079                 if (ret != 0) break;
2080
2081                 pthread_rwlock_rdlock(&lock);
2082                 current = current->next;
2083                 pthread_rwlock_unlock(&lock);
2084         }
2085         return ret;
2086 }
2087
2088 static void error(const char *fmt, ...)
2089 {
2090         va_list ap;
2091         va_start(ap, fmt);
2092         if (!runtime) {
2093                 vdprintf(2, fmt, ap);
2094                 dprintf(2, "\n");
2095                 ldso_fail = 1;
2096                 va_end(ap);
2097                 return;
2098         }
2099         __dl_vseterr(fmt, ap);
2100         va_end(ap);
2101 }