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