nsz Git - musl/blob - 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 #define container_of(p,t,m) ((t*)((char *)(p)-offsetof(t,m)))
  33
  34 struct debug {
  35         int ver;
  36         void *head;
  37         void (*bp)(void);
  38         int state;
  39         void *base;
  40 };
  41
  42 struct td_index {
  43         size_t args[2];
  44         struct td_index *next;
  45 };
  46
  47 struct dso {
  48 #if DL_FDPIC
  49         struct fdpic_loadmap *loadmap;
  50 #else
  51         unsigned char *base;
  52 #endif
  53         char *name;
  54         size_t *dynv;
  55         struct dso *next, *prev;
  56
  57         Phdr *phdr;
  58         int phnum;
  59         size_t phentsize;
  60         Sym *syms;
  61         Elf_Symndx *hashtab;
  62         uint32_t *ghashtab;
  63         int16_t *versym;
  64         char *strings;
  65         struct dso *syms_next, *lazy_next;
  66         size_t *lazy, lazy_cnt;
  67         unsigned char *map;
  68         size_t map_len;
  69         dev_t dev;
  70         ino_t ino;
  71         char relocated;
  72         char constructed;
  73         char kernel_mapped;
  74         struct dso **deps, *needed_by;
  75         char *rpath_orig, *rpath;
  76         struct tls_module tls;
  77         size_t tls_id;
  78         size_t relro_start, relro_end;
  79         uintptr_t *new_dtv;
  80         unsigned char *new_tls;
  81         volatile int new_dtv_idx, new_tls_idx;
  82         struct td_index *td_index;
  83         struct dso *fini_next;
  84         char *shortname;
  85 #if DL_FDPIC
  86         unsigned char *base;
  87 #else
  88         struct fdpic_loadmap *loadmap;
  89 #endif
  90         struct funcdesc {
  91                 void *addr;
  92                 size_t *got;
  93         } *funcdescs;
  94         size_t *got;
  95         char buf[];
  96 };
  97
  98 struct symdef {
  99         Sym *sym;
 100         struct dso *dso;
 101 };
 102
 103 static struct builtin_tls {
 104         char c;
 105         struct pthread pt;
 106         void *space[16];
 107 } builtin_tls[1];
 108 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
 109
 110 #define ADDEND_LIMIT 4096
 111 static size_t *saved_addends, *apply_addends_to;
 112
 113 static struct dso ldso;
 114 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
 115 static char *env_path, *sys_path;
 116 static unsigned long long gencnt;
 117 static int runtime;
 118 static int ldd_mode;
 119 static int ldso_fail;
 120 static int noload;
 121 static jmp_buf *rtld_fail;
 122 static pthread_rwlock_t lock;
 123 static struct debug debug;
 124 static struct tls_module *tls_tail;
 125 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
 126 static size_t static_tls_cnt;
 127 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 128 static struct fdpic_loadmap *app_loadmap;
 129 static struct fdpic_dummy_loadmap app_dummy_loadmap;
 130 static struct dso *const nodeps_dummy;
 131
 132 struct debug *_dl_debug_addr = &debug;
 133
 134 extern hidden int __malloc_replaced;
 135
 136 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
 137
 138 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
 139
 140 weak_alias(__init_array_start, __init_array_end);
 141 weak_alias(__fini_array_start, __fini_array_end);
 142
 143 static int dl_strcmp(const char *l, const char *r)
 144 {
 145         for (; *l==*r && *l; l++, r++);
 146         return *(unsigned char *)l - *(unsigned char *)r;
 147 }
 148 #define strcmp(l,r) dl_strcmp(l,r)
 149
 150 /* Compute load address for a virtual address in a given dso. */
 151 #if DL_FDPIC
 152 static void *laddr(const struct dso *p, size_t v)
 153 {
 154         size_t j=0;
 155         if (!p->loadmap) return p->base + v;
 156         for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
 157         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 158 }
 159 static void *laddr_pg(const struct dso *p, size_t v)
 160 {
 161         size_t j=0;
 162         size_t pgsz = PAGE_SIZE;
 163         if (!p->loadmap) return p->base + v;
 164         for (j=0; ; j++) {
 165                 size_t a = p->loadmap->segs[j].p_vaddr;
 166                 size_t b = a + p->loadmap->segs[j].p_memsz;
 167                 a &= -pgsz;
 168                 b += pgsz-1;
 169                 b &= -pgsz;
 170                 if (v-a<b-a) break;
 171         }
 172         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 173 }
 174 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
 175         laddr(p, v), (p)->got })
 176 #else
 177 #define laddr(p, v) (void *)((p)->base + (v))
 178 #define laddr_pg(p, v) laddr(p, v)
 179 #define fpaddr(p, v) ((void (*)())laddr(p, v))
 180 #endif
 181
 182 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 183 {
 184         size_t i;
 185         for (i=0; i<cnt; i++) a[i] = 0;
 186         for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
 187                 a[0] |= 1UL<<v[0];
 188                 a[v[0]] = v[1];
 189         }
 190 }
 191
 192 static int search_vec(size_t *v, size_t *r, size_t key)
 193 {
 194         for (; v[0]!=key; v+=2)
 195                 if (!v[0]) return 0;
 196         *r = v[1];
 197         return 1;
 198 }
 199
 200 static uint32_t sysv_hash(const char *s0)
 201 {
 202         const unsigned char *s = (void *)s0;
 203         uint_fast32_t h = 0;
 204         while (*s) {
 205                 h = 16*h + *s++;
 206                 h ^= h>>24 & 0xf0;
 207         }
 208         return h & 0xfffffff;
 209 }
 210
 211 static uint32_t gnu_hash(const char *s0)
 212 {
 213         const unsigned char *s = (void *)s0;
 214         uint_fast32_t h = 5381;
 215         for (; *s; s++)
 216                 h += h*32 + *s;
 217         return h;
 218 }
 219
 220 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 221 {
 222         size_t i;
 223         Sym *syms = dso->syms;
 224         Elf_Symndx *hashtab = dso->hashtab;
 225         char *strings = dso->strings;
 226         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 227                 if ((!dso->versym || dso->versym[i] >= 0)
 228                     && (!strcmp(s, strings+syms[i].st_name)))
 229                         return syms+i;
 230         }
 231         return 0;
 232 }
 233
 234 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
 235 {
 236         uint32_t nbuckets = hashtab[0];
 237         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 238         uint32_t i = buckets[h1 % nbuckets];
 239
 240         if (!i) return 0;
 241
 242         uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
 243
 244         for (h1 |= 1; ; i++) {
 245                 uint32_t h2 = *hashval++;
 246                 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
 247                     && !strcmp(s, dso->strings + dso->syms[i].st_name))
 248                         return dso->syms+i;
 249                 if (h2 & 1) break;
 250         }
 251
 252         return 0;
 253 }
 254
 255 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
 256 {
 257         const size_t *bloomwords = (const void *)(hashtab+4);
 258         size_t f = bloomwords[fofs & (hashtab[2]-1)];
 259         if (!(f & fmask)) return 0;
 260
 261         f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
 262         if (!(f & 1)) return 0;
 263
 264         return gnu_lookup(h1, hashtab, dso, s);
 265 }
 266
 267 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 268 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 269
 270 #ifndef ARCH_SYM_REJECT_UND
 271 #define ARCH_SYM_REJECT_UND(s) 0
 272 #endif
 273
 274 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 275 {
 276         uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
 277         size_t ghm = 1ul << gh % (8*sizeof(size_t));
 278         struct symdef def = {0};
 279         for (; dso; dso=dso->syms_next) {
 280                 Sym *sym;
 281                 if ((ght = dso->ghashtab)) {
 282                         sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
 283                 } else {
 284                         if (!h) h = sysv_hash(s);
 285                         sym = sysv_lookup(s, h, dso);
 286                 }
 287                 if (!sym) continue;
 288                 if (!sym->st_shndx)
 289                         if (need_def || (sym->st_info&0xf) == STT_TLS
 290                             || ARCH_SYM_REJECT_UND(sym))
 291                                 continue;
 292                 if (!sym->st_value)
 293                         if ((sym->st_info&0xf) != STT_TLS)
 294                                 continue;
 295                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 296                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 297                 def.sym = sym;
 298                 def.dso = dso;
 299                 break;
 300         }
 301         return def;
 302 }
 303
 304 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 305 {
 306         unsigned char *base = dso->base;
 307         Sym *syms = dso->syms;
 308         char *strings = dso->strings;
 309         Sym *sym;
 310         const char *name;
 311         void *ctx;
 312         int type;
 313         int sym_index;
 314         struct symdef def;
 315         size_t *reloc_addr;
 316         size_t sym_val;
 317         size_t tls_val;
 318         size_t addend;
 319         int skip_relative = 0, reuse_addends = 0, save_slot = 0;
 320
 321         if (dso == &ldso) {
 322                 /* Only ldso's REL table needs addend saving/reuse. */
 323                 if (rel == apply_addends_to)
 324                         reuse_addends = 1;
 325                 skip_relative = 1;
 326         }
 327
 328         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 329                 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
 330                 type = R_TYPE(rel[1]);
 331                 if (type == REL_NONE) continue;
 332                 reloc_addr = laddr(dso, rel[0]);
 333
 334                 if (stride > 2) {
 335                         addend = rel[2];
 336                 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
 337                         addend = 0;
 338                 } else if (reuse_addends) {
 339                         /* Save original addend in stage 2 where the dso
 340                          * chain consists of just ldso; otherwise read back
 341                          * saved addend since the inline one was clobbered. */
 342                         if (head==&ldso)
 343                                 saved_addends[save_slot] = *reloc_addr;
 344                         addend = saved_addends[save_slot++];
 345                 } else {
 346                         addend = *reloc_addr;
 347                 }
 348
 349                 sym_index = R_SYM(rel[1]);
 350                 if (sym_index) {
 351                         sym = syms + sym_index;
 352                         name = strings + sym->st_name;
 353                         ctx = type==REL_COPY ? head->syms_next : head;
 354                         def = (sym->st_info&0xf) == STT_SECTION
 355                                 ? (struct symdef){ .dso = dso, .sym = sym }
 356                                 : find_sym(ctx, name, type==REL_PLT);
 357                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 358                             || sym->st_info>>4 != STB_WEAK)) {
 359                                 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
 360                                         dso->lazy[3*dso->lazy_cnt+0] = rel[0];
 361                                         dso->lazy[3*dso->lazy_cnt+1] = rel[1];
 362                                         dso->lazy[3*dso->lazy_cnt+2] = addend;
 363                                         dso->lazy_cnt++;
 364                                         continue;
 365                                 }
 366                                 error("Error relocating %s: %s: symbol not found",
 367                                         dso->name, name);
 368                                 if (runtime) longjmp(*rtld_fail, 1);
 369                                 continue;
 370                         }
 371                 } else {
 372                         sym = 0;
 373                         def.sym = 0;
 374                         def.dso = dso;
 375                 }
 376
 377                 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
 378                 tls_val = def.sym ? def.sym->st_value : 0;
 379
 380                 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
 381                     && runtime && def.dso->tls_id > static_tls_cnt) {
 382                         error("Error relocating %s: %s: initial-exec TLS "
 383                                 "resolves to dynamic definition in %s",
 384                                 dso->name, name, def.dso->name);
 385                         longjmp(*rtld_fail, 1);
 386                 }
 387
 388                 switch(type) {
 389                 case REL_NONE:
 390                         break;
 391                 case REL_OFFSET:
 392                         addend -= (size_t)reloc_addr;
 393                 case REL_SYMBOLIC:
 394                 case REL_GOT:
 395                 case REL_PLT:
 396                         *reloc_addr = sym_val + addend;
 397                         break;
 398                 case REL_RELATIVE:
 399                         *reloc_addr = (size_t)base + addend;
 400                         break;
 401                 case REL_SYM_OR_REL:
 402                         if (sym) *reloc_addr = sym_val + addend;
 403                         else *reloc_addr = (size_t)base + addend;
 404                         break;
 405                 case REL_COPY:
 406                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 407                         break;
 408                 case REL_OFFSET32:
 409                         *(uint32_t *)reloc_addr = sym_val + addend
 410                                 - (size_t)reloc_addr;
 411                         break;
 412                 case REL_FUNCDESC:
 413                         *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
 414                                 + (def.sym - def.dso->syms)) : 0;
 415                         break;
 416                 case REL_FUNCDESC_VAL:
 417                         if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
 418                         else *reloc_addr = sym_val;
 419                         reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
 420                         break;
 421                 case REL_DTPMOD:
 422                         *reloc_addr = def.dso->tls_id;
 423                         break;
 424                 case REL_DTPOFF:
 425                         *reloc_addr = tls_val + addend - DTP_OFFSET;
 426                         break;
 427 #ifdef TLS_ABOVE_TP
 428                 case REL_TPOFF:
 429                         *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
 430                         break;
 431 #else
 432                 case REL_TPOFF:
 433                         *reloc_addr = tls_val - def.dso->tls.offset + addend;
 434                         break;
 435                 case REL_TPOFF_NEG:
 436                         *reloc_addr = def.dso->tls.offset - tls_val + addend;
 437                         break;
 438 #endif
 439                 case REL_TLSDESC:
 440                         if (stride<3) addend = reloc_addr[1];
 441                         if (runtime && def.dso->tls_id > static_tls_cnt) {
 442                                 struct td_index *new = malloc(sizeof *new);
 443                                 if (!new) {
 444                                         error(
 445                                         "Error relocating %s: cannot allocate TLSDESC for %s",
 446                                         dso->name, sym ? name : "(local)" );
 447                                         longjmp(*rtld_fail, 1);
 448                                 }
 449                                 new->next = dso->td_index;
 450                                 dso->td_index = new;
 451                                 new->args[0] = def.dso->tls_id;
 452                                 new->args[1] = tls_val + addend - DTP_OFFSET;
 453                                 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
 454                                 reloc_addr[1] = (size_t)new;
 455                         } else {
 456                                 reloc_addr[0] = (size_t)__tlsdesc_static;
 457 #ifdef TLS_ABOVE_TP
 458                                 reloc_addr[1] = tls_val + def.dso->tls.offset
 459                                         + TPOFF_K + addend;
 460 #else
 461                                 reloc_addr[1] = tls_val - def.dso->tls.offset
 462                                         + addend;
 463 #endif
 464                         }
 465 #ifdef TLSDESC_BACKWARDS
 466                         /* Some archs (32-bit ARM at least) invert the order of
 467                          * the descriptor members. Fix them up here. */
 468                         size_t tmp = reloc_addr[0];
 469                         reloc_addr[0] = reloc_addr[1];
 470                         reloc_addr[1] = tmp;
 471 #endif
 472                         break;
 473                 default:
 474                         error("Error relocating %s: unsupported relocation type %d",
 475                                 dso->name, type);
 476                         if (runtime) longjmp(*rtld_fail, 1);
 477                         continue;
 478                 }
 479         }
 480 }
 481
 482 static void redo_lazy_relocs()
 483 {
 484         struct dso *p = lazy_head, *next;
 485         lazy_head = 0;
 486         for (; p; p=next) {
 487                 next = p->lazy_next;
 488                 size_t size = p->lazy_cnt*3*sizeof(size_t);
 489                 p->lazy_cnt = 0;
 490                 do_relocs(p, p->lazy, size, 3);
 491                 if (p->lazy_cnt) {
 492                         p->lazy_next = lazy_head;
 493                         lazy_head = p;
 494                 } else {
 495                         free(p->lazy);
 496                         p->lazy = 0;
 497                         p->lazy_next = 0;
 498                 }
 499         }
 500 }
 501
 502 /* A huge hack: to make up for the wastefulness of shared libraries
 503  * needing at least a page of dirty memory even if they have no global
 504  * data, we reclaim the gaps at the beginning and end of writable maps
 505  * and "donate" them to the heap. */
 506
 507 static void reclaim(struct dso *dso, size_t start, size_t end)
 508 {
 509         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 510         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 511         if (start >= end) return;
 512         char *base = laddr_pg(dso, start);
 513         __malloc_donate(base, base+(end-start));
 514 }
 515
 516 static void reclaim_gaps(struct dso *dso)
 517 {
 518         Phdr *ph = dso->phdr;
 519         size_t phcnt = dso->phnum;
 520
 521         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 522                 if (ph->p_type!=PT_LOAD) continue;
 523                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 524                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 525                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 526                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 527         }
 528 }
 529
 530 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
 531 {
 532         static int no_map_fixed;
 533         char *q;
 534         if (!no_map_fixed) {
 535                 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
 536                 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
 537                         return q;
 538                 no_map_fixed = 1;
 539         }
 540         /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
 541         if (flags & MAP_ANONYMOUS) {
 542                 memset(p, 0, n);
 543                 return p;
 544         }
 545         ssize_t r;
 546         if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
 547         for (q=p; n; q+=r, off+=r, n-=r) {
 548                 r = read(fd, q, n);
 549                 if (r < 0 && errno != EINTR) return MAP_FAILED;
 550                 if (!r) {
 551                         memset(q, 0, n);
 552                         break;
 553                 }
 554         }
 555         return p;
 556 }
 557
 558 static void unmap_library(struct dso *dso)
 559 {
 560         if (dso->loadmap) {
 561                 size_t i;
 562                 for (i=0; i<dso->loadmap->nsegs; i++) {
 563                         if (!dso->loadmap->segs[i].p_memsz)
 564                                 continue;
 565                         munmap((void *)dso->loadmap->segs[i].addr,
 566                                 dso->loadmap->segs[i].p_memsz);
 567                 }
 568                 free(dso->loadmap);
 569         } else if (dso->map && dso->map_len) {
 570                 munmap(dso->map, dso->map_len);
 571         }
 572 }
 573
 574 static void *map_library(int fd, struct dso *dso)
 575 {
 576         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 577         void *allocated_buf=0;
 578         size_t phsize;
 579         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 580         size_t this_min, this_max;
 581         size_t nsegs = 0;
 582         off_t off_start;
 583         Ehdr *eh;
 584         Phdr *ph, *ph0;
 585         unsigned prot;
 586         unsigned char *map=MAP_FAILED, *base;
 587         size_t dyn=0;
 588         size_t tls_image=0;
 589         size_t i;
 590
 591         ssize_t l = read(fd, buf, sizeof buf);
 592         eh = buf;
 593         if (l<0) return 0;
 594         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 595                 goto noexec;
 596         phsize = eh->e_phentsize * eh->e_phnum;
 597         if (phsize > sizeof buf - sizeof *eh) {
 598                 allocated_buf = malloc(phsize);
 599                 if (!allocated_buf) return 0;
 600                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 601                 if (l < 0) goto error;
 602                 if (l != phsize) goto noexec;
 603                 ph = ph0 = allocated_buf;
 604         } else if (eh->e_phoff + phsize > l) {
 605                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 606                 if (l < 0) goto error;
 607                 if (l != phsize) goto noexec;
 608                 ph = ph0 = (void *)(buf + 1);
 609         } else {
 610                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 611         }
 612         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 613                 if (ph->p_type == PT_DYNAMIC) {
 614                         dyn = ph->p_vaddr;
 615                 } else if (ph->p_type == PT_TLS) {
 616                         tls_image = ph->p_vaddr;
 617                         dso->tls.align = ph->p_align;
 618                         dso->tls.len = ph->p_filesz;
 619                         dso->tls.size = ph->p_memsz;
 620                 } else if (ph->p_type == PT_GNU_RELRO) {
 621                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 622                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 623                 } else if (ph->p_type == PT_GNU_STACK) {
 624                         if (!runtime && ph->p_memsz > __default_stacksize) {
 625                                 __default_stacksize =
 626                                         ph->p_memsz < DEFAULT_STACK_MAX ?
 627                                         ph->p_memsz : DEFAULT_STACK_MAX;
 628                         }
 629                 }
 630                 if (ph->p_type != PT_LOAD) continue;
 631                 nsegs++;
 632                 if (ph->p_vaddr < addr_min) {
 633                         addr_min = ph->p_vaddr;
 634                         off_start = ph->p_offset;
 635                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 636                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 637                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 638                 }
 639                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 640                         addr_max = ph->p_vaddr+ph->p_memsz;
 641                 }
 642         }
 643         if (!dyn) goto noexec;
 644         if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
 645                 dso->loadmap = calloc(1, sizeof *dso->loadmap
 646                         + nsegs * sizeof *dso->loadmap->segs);
 647                 if (!dso->loadmap) goto error;
 648                 dso->loadmap->nsegs = nsegs;
 649                 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
 650                         if (ph->p_type != PT_LOAD) continue;
 651                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 652                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 653                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 654                         map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
 655                                 prot, MAP_PRIVATE,
 656                                 fd, ph->p_offset & -PAGE_SIZE);
 657                         if (map == MAP_FAILED) {
 658                                 unmap_library(dso);
 659                                 goto error;
 660                         }
 661                         dso->loadmap->segs[i].addr = (size_t)map +
 662                                 (ph->p_vaddr & PAGE_SIZE-1);
 663                         dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
 664                         dso->loadmap->segs[i].p_memsz = ph->p_memsz;
 665                         i++;
 666                         if (prot & PROT_WRITE) {
 667                                 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
 668                                         + ph->p_filesz;
 669                                 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
 670                                 size_t pgend = brk + ph->p_memsz - ph->p_filesz
 671                                         + PAGE_SIZE-1 & -PAGE_SIZE;
 672                                 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
 673                                         pgend-pgbrk, prot,
 674                                         MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
 675                                         -1, off_start) == MAP_FAILED)
 676                                         goto error;
 677                                 memset(map + brk, 0, pgbrk-brk);
 678                         }
 679                 }
 680                 map = (void *)dso->loadmap->segs[0].addr;
 681                 map_len = 0;
 682                 goto done_mapping;
 683         }
 684         addr_max += PAGE_SIZE-1;
 685         addr_max &= -PAGE_SIZE;
 686         addr_min &= -PAGE_SIZE;
 687         off_start &= -PAGE_SIZE;
 688         map_len = addr_max - addr_min + off_start;
 689         /* The first time, we map too much, possibly even more than
 690          * the length of the file. This is okay because we will not
 691          * use the invalid part; we just need to reserve the right
 692          * amount of virtual address space to map over later. */
 693         map = DL_NOMMU_SUPPORT
 694                 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
 695                         MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
 696                 : mmap((void *)addr_min, map_len, prot,
 697                         MAP_PRIVATE, fd, off_start);
 698         if (map==MAP_FAILED) goto error;
 699         dso->map = map;
 700         dso->map_len = map_len;
 701         /* If the loaded file is not relocatable and the requested address is
 702          * not available, then the load operation must fail. */
 703         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 704                 errno = EBUSY;
 705                 goto error;
 706         }
 707         base = map - addr_min;
 708         dso->phdr = 0;
 709         dso->phnum = 0;
 710         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 711                 if (ph->p_type != PT_LOAD) continue;
 712                 /* Check if the programs headers are in this load segment, and
 713                  * if so, record the address for use by dl_iterate_phdr. */
 714                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 715                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 716                         dso->phdr = (void *)(base + ph->p_vaddr
 717                                 + (eh->e_phoff-ph->p_offset));
 718                         dso->phnum = eh->e_phnum;
 719                         dso->phentsize = eh->e_phentsize;
 720                 }
 721                 this_min = ph->p_vaddr & -PAGE_SIZE;
 722                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 723                 off_start = ph->p_offset & -PAGE_SIZE;
 724                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 725                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 726                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 727                 /* Reuse the existing mapping for the lowest-address LOAD */
 728                 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
 729                         if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 730                                 goto error;
 731                 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
 732                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 733                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 734                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 735                         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)
 736                                 goto error;
 737                 }
 738         }
 739         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 740                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 741                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
 742                             && errno != ENOSYS)
 743                                 goto error;
 744                         break;
 745                 }
 746 done_mapping:
 747         dso->base = base;
 748         dso->dynv = laddr(dso, dyn);
 749         if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
 750         free(allocated_buf);
 751         return map;
 752 noexec:
 753         errno = ENOEXEC;
 754 error:
 755         if (map!=MAP_FAILED) unmap_library(dso);
 756         free(allocated_buf);
 757         return 0;
 758 }
 759
 760 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 761 {
 762         size_t l;
 763         int fd;
 764         for (;;) {
 765                 s += strspn(s, ":\n");
 766                 l = strcspn(s, ":\n");
 767                 if (l-1 >= INT_MAX) return -1;
 768                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
 769                         if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 770                         switch (errno) {
 771                         case ENOENT:
 772                         case ENOTDIR:
 773                         case EACCES:
 774                         case ENAMETOOLONG:
 775                                 break;
 776                         default:
 777                                 /* Any negative value but -1 will inhibit
 778                                  * futher path search. */
 779                                 return -2;
 780                         }
 781                 }
 782                 s += l;
 783         }
 784 }
 785
 786 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 787 {
 788         size_t n, l;
 789         const char *s, *t, *origin;
 790         char *d;
 791         if (p->rpath || !p->rpath_orig) return 0;
 792         if (!strchr(p->rpath_orig, '$')) {
 793                 p->rpath = p->rpath_orig;
 794                 return 0;
 795         }
 796         n = 0;
 797         s = p->rpath_orig;
 798         while ((t=strchr(s, '$'))) {
 799                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 800                         return 0;
 801                 s = t+1;
 802                 n++;
 803         }
 804         if (n > SSIZE_MAX/PATH_MAX) return 0;
 805
 806         if (p->kernel_mapped) {
 807                 /* $ORIGIN searches cannot be performed for the main program
 808                  * when it is suid/sgid/AT_SECURE. This is because the
 809                  * pathname is under the control of the caller of execve.
 810                  * For libraries, however, $ORIGIN can be processed safely
 811                  * since the library's pathname came from a trusted source
 812                  * (either system paths or a call to dlopen). */
 813                 if (libc.secure)
 814                         return 0;
 815                 l = readlink("/proc/self/exe", buf, buf_size);
 816                 if (l == -1) switch (errno) {
 817                 case ENOENT:
 818                 case ENOTDIR:
 819                 case EACCES:
 820                         break;
 821                 default:
 822                         return -1;
 823                 }
 824                 if (l >= buf_size)
 825                         return 0;
 826                 buf[l] = 0;
 827                 origin = buf;
 828         } else {
 829                 origin = p->name;
 830         }
 831         t = strrchr(origin, '/');
 832         if (t) {
 833                 l = t-origin;
 834         } else {
 835                 /* Normally p->name will always be an absolute or relative
 836                  * pathname containing at least one '/' character, but in the
 837                  * case where ldso was invoked as a command to execute a
 838                  * program in the working directory, app.name may not. Fix. */
 839                 origin = ".";
 840                 l = 1;
 841         }
 842         /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
 843         if (libc.secure && *origin != '/')
 844                 return 0;
 845         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 846         if (!p->rpath) return -1;
 847
 848         d = p->rpath;
 849         s = p->rpath_orig;
 850         while ((t=strchr(s, '$'))) {
 851                 memcpy(d, s, t-s);
 852                 d += t-s;
 853                 memcpy(d, origin, l);
 854                 d += l;
 855                 /* It was determined previously that the '$' is followed
 856                  * either by "ORIGIN" or "{ORIGIN}". */
 857                 s = t + 7 + 2*(t[1]=='{');
 858         }
 859         strcpy(d, s);
 860         return 0;
 861 }
 862
 863 static void decode_dyn(struct dso *p)
 864 {
 865         size_t dyn[DYN_CNT];
 866         decode_vec(p->dynv, dyn, DYN_CNT);
 867         p->syms = laddr(p, dyn[DT_SYMTAB]);
 868         p->strings = laddr(p, dyn[DT_STRTAB]);
 869         if (dyn[0]&(1<<DT_HASH))
 870                 p->hashtab = laddr(p, dyn[DT_HASH]);
 871         if (dyn[0]&(1<<DT_RPATH))
 872                 p->rpath_orig = p->strings + dyn[DT_RPATH];
 873         if (dyn[0]&(1<<DT_RUNPATH))
 874                 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
 875         if (dyn[0]&(1<<DT_PLTGOT))
 876                 p->got = laddr(p, dyn[DT_PLTGOT]);
 877         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 878                 p->ghashtab = laddr(p, *dyn);
 879         if (search_vec(p->dynv, dyn, DT_VERSYM))
 880                 p->versym = laddr(p, *dyn);
 881 }
 882
 883 static size_t count_syms(struct dso *p)
 884 {
 885         if (p->hashtab) return p->hashtab[1];
 886
 887         size_t nsym, i;
 888         uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
 889         uint32_t *hashval;
 890         for (i = nsym = 0; i < p->ghashtab[0]; i++) {
 891                 if (buckets[i] > nsym)
 892                         nsym = buckets[i];
 893         }
 894         if (nsym) {
 895                 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
 896                 do nsym++;
 897                 while (!(*hashval++ & 1));
 898         }
 899         return nsym;
 900 }
 901
 902 static void *dl_mmap(size_t n)
 903 {
 904         void *p;
 905         int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
 906 #ifdef SYS_mmap2
 907         p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
 908 #else
 909         p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
 910 #endif
 911         return p == MAP_FAILED ? 0 : p;
 912 }
 913
 914 static void makefuncdescs(struct dso *p)
 915 {
 916         static int self_done;
 917         size_t nsym = count_syms(p);
 918         size_t i, size = nsym * sizeof(*p->funcdescs);
 919
 920         if (!self_done) {
 921                 p->funcdescs = dl_mmap(size);
 922                 self_done = 1;
 923         } else {
 924                 p->funcdescs = malloc(size);
 925         }
 926         if (!p->funcdescs) {
 927                 if (!runtime) a_crash();
 928                 error("Error allocating function descriptors for %s", p->name);
 929                 longjmp(*rtld_fail, 1);
 930         }
 931         for (i=0; i<nsym; i++) {
 932                 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
 933                         p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
 934                         p->funcdescs[i].got = p->got;
 935                 } else {
 936                         p->funcdescs[i].addr = 0;
 937                         p->funcdescs[i].got = 0;
 938                 }
 939         }
 940 }
 941
 942 static struct dso *load_library(const char *name, struct dso *needed_by)
 943 {
 944         char buf[2*NAME_MAX+2];
 945         const char *pathname;
 946         unsigned char *map;
 947         struct dso *p, temp_dso = {0};
 948         int fd;
 949         struct stat st;
 950         size_t alloc_size;
 951         int n_th = 0;
 952         int is_self = 0;
 953
 954         if (!*name) {
 955                 errno = EINVAL;
 956                 return 0;
 957         }
 958
 959         /* Catch and block attempts to reload the implementation itself */
 960         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 961                 static const char reserved[] =
 962                         "c.pthread.rt.m.dl.util.xnet.";
 963                 const char *rp, *next;
 964                 for (rp=reserved; *rp; rp=next) {
 965                         next = strchr(rp, '.') + 1;
 966                         if (strncmp(name+3, rp, next-rp) == 0)
 967                                 break;
 968                 }
 969                 if (*rp) {
 970                         if (ldd_mode) {
 971                                 /* Track which names have been resolved
 972                                  * and only report each one once. */
 973                                 static unsigned reported;
 974                                 unsigned mask = 1U<<(rp-reserved);
 975                                 if (!(reported & mask)) {
 976                                         reported |= mask;
 977                                         dprintf(1, "\t%s => %s (%p)\n",
 978                                                 name, ldso.name,
 979                                                 ldso.base);
 980                                 }
 981                         }
 982                         is_self = 1;
 983                 }
 984         }
 985         if (!strcmp(name, ldso.name)) is_self = 1;
 986         if (is_self) {
 987                 if (!ldso.prev) {
 988                         tail->next = &ldso;
 989                         ldso.prev = tail;
 990                         tail = &ldso;
 991                 }
 992                 return &ldso;
 993         }
 994         if (strchr(name, '/')) {
 995                 pathname = name;
 996                 fd = open(name, O_RDONLY|O_CLOEXEC);
 997         } else {
 998                 /* Search for the name to see if it's already loaded */
 999                 for (p=head->next; p; p=p->next) {
1000                         if (p->shortname && !strcmp(p->shortname, name)) {
1001                                 return p;
1002                         }
1003                 }
1004                 if (strlen(name) > NAME_MAX) return 0;
1005                 fd = -1;
1006                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1007                 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1008                         if (fixup_rpath(p, buf, sizeof buf) < 0)
1009                                 fd = -2; /* Inhibit further search. */
1010                         if (p->rpath)
1011                                 fd = path_open(name, p->rpath, buf, sizeof buf);
1012                 }
1013                 if (fd == -1) {
1014                         if (!sys_path) {
1015                                 char *prefix = 0;
1016                                 size_t prefix_len;
1017                                 if (ldso.name[0]=='/') {
1018                                         char *s, *t, *z;
1019                                         for (s=t=z=ldso.name; *s; s++)
1020                                                 if (*s=='/') z=t, t=s;
1021                                         prefix_len = z-ldso.name;
1022                                         if (prefix_len < PATH_MAX)
1023                                                 prefix = ldso.name;
1024                                 }
1025                                 if (!prefix) {
1026                                         prefix = "";
1027                                         prefix_len = 0;
1028                                 }
1029                                 char etc_ldso_path[prefix_len + 1
1030                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1031                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1032                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1033                                         (int)prefix_len, prefix);
1034                                 FILE *f = fopen(etc_ldso_path, "rbe");
1035                                 if (f) {
1036                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1037                                                 free(sys_path);
1038                                                 sys_path = "";
1039                                         }
1040                                         fclose(f);
1041                                 } else if (errno != ENOENT) {
1042                                         sys_path = "";
1043                                 }
1044                         }
1045                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1046                         fd = path_open(name, sys_path, buf, sizeof buf);
1047                 }
1048                 pathname = buf;
1049         }
1050         if (fd < 0) return 0;
1051         if (fstat(fd, &st) < 0) {
1052                 close(fd);
1053                 return 0;
1054         }
1055         for (p=head->next; p; p=p->next) {
1056                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1057                         /* If this library was previously loaded with a
1058                          * pathname but a search found the same inode,
1059                          * setup its shortname so it can be found by name. */
1060                         if (!p->shortname && pathname != name)
1061                                 p->shortname = strrchr(p->name, '/')+1;
1062                         close(fd);
1063                         return p;
1064                 }
1065         }
1066         map = noload ? 0 : map_library(fd, &temp_dso);
1067         close(fd);
1068         if (!map) return 0;
1069
1070         /* Avoid the danger of getting two versions of libc mapped into the
1071          * same process when an absolute pathname was used. The symbols
1072          * checked are chosen to catch both musl and glibc, and to avoid
1073          * false positives from interposition-hack libraries. */
1074         decode_dyn(&temp_dso);
1075         if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1076             find_sym(&temp_dso, "stdin", 1).sym) {
1077                 unmap_library(&temp_dso);
1078                 return load_library("libc.so", needed_by);
1079         }
1080         /* Past this point, if we haven't reached runtime yet, ldso has
1081          * committed either to use the mapped library or to abort execution.
1082          * Unmapping is not possible, so we can safely reclaim gaps. */
1083         if (!runtime) reclaim_gaps(&temp_dso);
1084
1085         /* Allocate storage for the new DSO. When there is TLS, this
1086          * storage must include a reservation for all pre-existing
1087          * threads to obtain copies of both the new TLS, and an
1088          * extended DTV capable of storing an additional slot for
1089          * the newly-loaded DSO. */
1090         alloc_size = sizeof *p + strlen(pathname) + 1;
1091         if (runtime && temp_dso.tls.image) {
1092                 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1093                         + sizeof(void *) * (tls_cnt+3);
1094                 n_th = libc.threads_minus_1 + 1;
1095                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1096                 else alloc_size += n_th * per_th;
1097         }
1098         p = calloc(1, alloc_size);
1099         if (!p) {
1100                 unmap_library(&temp_dso);
1101                 return 0;
1102         }
1103         memcpy(p, &temp_dso, sizeof temp_dso);
1104         p->dev = st.st_dev;
1105         p->ino = st.st_ino;
1106         p->needed_by = needed_by;
1107         p->name = p->buf;
1108         strcpy(p->name, pathname);
1109         /* Add a shortname only if name arg was not an explicit pathname. */
1110         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1111         if (p->tls.image) {
1112                 p->tls_id = ++tls_cnt;
1113                 tls_align = MAXP2(tls_align, p->tls.align);
1114 #ifdef TLS_ABOVE_TP
1115                 p->tls.offset = tls_offset + ( (tls_align-1) &
1116                         -(tls_offset + (uintptr_t)p->tls.image) );
1117                 tls_offset += p->tls.size;
1118 #else
1119                 tls_offset += p->tls.size + p->tls.align - 1;
1120                 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1121                         & (p->tls.align-1);
1122                 p->tls.offset = tls_offset;
1123 #endif
1124                 p->new_dtv = (void *)(-sizeof(size_t) &
1125                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1126                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1127                 if (tls_tail) tls_tail->next = &p->tls;
1128                 else libc.tls_head = &p->tls;
1129                 tls_tail = &p->tls;
1130         }
1131
1132         tail->next = p;
1133         p->prev = tail;
1134         tail = p;
1135
1136         if (DL_FDPIC) makefuncdescs(p);
1137
1138         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1139
1140         return p;
1141 }
1142
1143 static void load_deps(struct dso *p)
1144 {
1145         size_t i, ndeps=0;
1146         struct dso ***deps = &p->deps, **tmp, *dep;
1147         for (; p; p=p->next) {
1148                 for (i=0; p->dynv[i]; i+=2) {
1149                         if (p->dynv[i] != DT_NEEDED) continue;
1150                         dep = load_library(p->strings + p->dynv[i+1], p);
1151                         if (!dep) {
1152                                 error("Error loading shared library %s: %m (needed by %s)",
1153                                         p->strings + p->dynv[i+1], p->name);
1154                                 if (runtime) longjmp(*rtld_fail, 1);
1155                                 continue;
1156                         }
1157                         if (runtime) {
1158                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1159                                 if (!tmp) longjmp(*rtld_fail, 1);
1160                                 tmp[ndeps++] = dep;
1161                                 tmp[ndeps] = 0;
1162                                 *deps = tmp;
1163                         }
1164                 }
1165         }
1166         if (!*deps) *deps = (struct dso **)&nodeps_dummy;
1167 }
1168
1169 static void load_preload(char *s)
1170 {
1171         int tmp;
1172         char *z;
1173         for (z=s; *z; s=z) {
1174                 for (   ; *s && (isspace(*s) || *s==':'); s++);
1175                 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1176                 tmp = *z;
1177                 *z = 0;
1178                 load_library(s, 0);
1179                 *z = tmp;
1180         }
1181 }
1182
1183 static void add_syms(struct dso *p)
1184 {
1185         if (!p->syms_next && syms_tail != p) {
1186                 syms_tail->syms_next = p;
1187                 syms_tail = p;
1188         }
1189 }
1190
1191 static void revert_syms(struct dso *old_tail)
1192 {
1193         struct dso *p, *next;
1194         /* Chop off the tail of the list of dsos that participate in
1195          * the global symbol table, reverting them to RTLD_LOCAL. */
1196         for (p=old_tail; p; p=next) {
1197                 next = p->syms_next;
1198                 p->syms_next = 0;
1199         }
1200         syms_tail = old_tail;
1201 }
1202
1203 static void do_mips_relocs(struct dso *p, size_t *got)
1204 {
1205         size_t i, j, rel[2];
1206         unsigned char *base = p->base;
1207         i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1208         if (p==&ldso) {
1209                 got += i;
1210         } else {
1211                 while (i--) *got++ += (size_t)base;
1212         }
1213         j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1214         i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1215         Sym *sym = p->syms + j;
1216         rel[0] = (unsigned char *)got - base;
1217         for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1218                 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1219                 do_relocs(p, rel, sizeof rel, 2);
1220         }
1221 }
1222
1223 static void reloc_all(struct dso *p)
1224 {
1225         size_t dyn[DYN_CNT];
1226         for (; p; p=p->next) {
1227                 if (p->relocated) continue;
1228                 decode_vec(p->dynv, dyn, DYN_CNT);
1229                 if (NEED_MIPS_GOT_RELOCS)
1230                         do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1231                 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1232                         2+(dyn[DT_PLTREL]==DT_RELA));
1233                 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1234                 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1235
1236                 if (head != &ldso && p->relro_start != p->relro_end &&
1237                     mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1238                     && errno != ENOSYS) {
1239                         error("Error relocating %s: RELRO protection failed: %m",
1240                                 p->name);
1241                         if (runtime) longjmp(*rtld_fail, 1);
1242                 }
1243
1244                 p->relocated = 1;
1245         }
1246 }
1247
1248 static void kernel_mapped_dso(struct dso *p)
1249 {
1250         size_t min_addr = -1, max_addr = 0, cnt;
1251         Phdr *ph = p->phdr;
1252         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1253                 if (ph->p_type == PT_DYNAMIC) {
1254                         p->dynv = laddr(p, ph->p_vaddr);
1255                 } else if (ph->p_type == PT_GNU_RELRO) {
1256                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1257                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1258                 } else if (ph->p_type == PT_GNU_STACK) {
1259                         if (!runtime && ph->p_memsz > __default_stacksize) {
1260                                 __default_stacksize =
1261                                         ph->p_memsz < DEFAULT_STACK_MAX ?
1262                                         ph->p_memsz : DEFAULT_STACK_MAX;
1263                         }
1264                 }
1265                 if (ph->p_type != PT_LOAD) continue;
1266                 if (ph->p_vaddr < min_addr)
1267                         min_addr = ph->p_vaddr;
1268                 if (ph->p_vaddr+ph->p_memsz > max_addr)
1269                         max_addr = ph->p_vaddr+ph->p_memsz;
1270         }
1271         min_addr &= -PAGE_SIZE;
1272         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1273         p->map = p->base + min_addr;
1274         p->map_len = max_addr - min_addr;
1275         p->kernel_mapped = 1;
1276 }
1277
1278 void __libc_exit_fini()
1279 {
1280         struct dso *p;
1281         size_t dyn[DYN_CNT];
1282         for (p=fini_head; p; p=p->fini_next) {
1283                 if (!p->constructed) continue;
1284                 decode_vec(p->dynv, dyn, DYN_CNT);
1285                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1286                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1287                         size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1288                         while (n--) ((void (*)(void))*--fn)();
1289                 }
1290 #ifndef NO_LEGACY_INITFINI
1291                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1292                         fpaddr(p, dyn[DT_FINI])();
1293 #endif
1294         }
1295 }
1296
1297 static void do_init_fini(struct dso *p)
1298 {
1299         size_t dyn[DYN_CNT];
1300         int need_locking = libc.threads_minus_1;
1301         /* Allow recursive calls that arise when a library calls
1302          * dlopen from one of its constructors, but block any
1303          * other threads until all ctors have finished. */
1304         if (need_locking) pthread_mutex_lock(&init_fini_lock);
1305         for (; p; p=p->prev) {
1306                 if (p->constructed) continue;
1307                 p->constructed = 1;
1308                 decode_vec(p->dynv, dyn, DYN_CNT);
1309                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1310                         p->fini_next = fini_head;
1311                         fini_head = p;
1312                 }
1313 #ifndef NO_LEGACY_INITFINI
1314                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1315                         fpaddr(p, dyn[DT_INIT])();
1316 #endif
1317                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1318                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1319                         size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1320                         while (n--) ((void (*)(void))*fn++)();
1321                 }
1322                 if (!need_locking && libc.threads_minus_1) {
1323                         need_locking = 1;
1324                         pthread_mutex_lock(&init_fini_lock);
1325                 }
1326         }
1327         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1328 }
1329
1330 void __libc_start_init(void)
1331 {
1332         do_init_fini(tail);
1333 }
1334
1335 static void dl_debug_state(void)
1336 {
1337 }
1338
1339 weak_alias(dl_debug_state, _dl_debug_state);
1340
1341 void __init_tls(size_t *auxv)
1342 {
1343 }
1344
1345 static void update_tls_size()
1346 {
1347         libc.tls_cnt = tls_cnt;
1348         libc.tls_align = tls_align;
1349         libc.tls_size = ALIGN(
1350                 (1+tls_cnt) * sizeof(void *) +
1351                 tls_offset +
1352                 sizeof(struct pthread) +
1353                 tls_align * 2,
1354         tls_align);
1355 }
1356
1357 static void install_new_tls(void)
1358 {
1359         sigset_t set;
1360         pthread_t self = __pthread_self(), td;
1361         struct dso *dtv_provider = container_of(tls_tail, struct dso, tls);
1362         uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv;
1363         struct dso *p;
1364         size_t i, j;
1365         size_t old_cnt = self->dtv[0];
1366
1367         __block_app_sigs(&set);
1368         __tl_lock();
1369         /* Copy existing dtv contents from all existing threads. */
1370         for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1371                 memcpy(newdtv+i, td->dtv,
1372                         (old_cnt+1)*sizeof(uintptr_t));
1373                 newdtv[i][0] = tls_cnt;
1374         }
1375         /* Install new dtls into the enlarged, uninstalled dtv copies. */
1376         for (p=head; ; p=p->next) {
1377                 if (p->tls_id <= old_cnt) continue;
1378                 unsigned char *mem = p->new_tls;
1379                 for (j=0; j<i; j++) {
1380                         unsigned char *new = mem;
1381                         new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1382                                 & (p->tls.align-1);
1383                         memcpy(new, p->tls.image, p->tls.len);
1384                         newdtv[j][p->tls_id] =
1385                                 (uintptr_t)new + DTP_OFFSET;
1386                         mem += p->tls.size + p->tls.align;
1387                 }
1388                 if (p->tls_id == tls_cnt) break;
1389         }
1390
1391         /* Broadcast barrier to ensure contents of new dtv is visible
1392          * if the new dtv pointer is. The __membarrier function has a
1393          * fallback emulation using signals for kernels that lack the
1394          * feature at the syscall level. */
1395
1396         __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1397
1398         /* Install new dtv for each thread. */
1399         for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1400                 td->dtv = td->dtv_copy = newdtv[j];
1401         }
1402
1403         __tl_unlock();
1404         __restore_sigs(&set);
1405 }
1406
1407 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1408  * following stage 2 and stage 3 functions via primitive symbolic lookup
1409  * since it does not have access to their addresses to begin with. */
1410
1411 /* Stage 2 of the dynamic linker is called after relative relocations
1412  * have been processed. It can make function calls to static functions
1413  * and access string literals and static data, but cannot use extern
1414  * symbols. Its job is to perform symbolic relocations on the dynamic
1415  * linker itself, but some of the relocations performed may need to be
1416  * replaced later due to copy relocations in the main program. */
1417
1418 hidden void __dls2(unsigned char *base, size_t *sp)
1419 {
1420         if (DL_FDPIC) {
1421                 void *p1 = (void *)sp[-2];
1422                 void *p2 = (void *)sp[-1];
1423                 if (!p1) {
1424                         size_t *auxv, aux[AUX_CNT];
1425                         for (auxv=sp+1+*sp+1; *auxv; auxv++);
1426                         auxv++;
1427                         decode_vec(auxv, aux, AUX_CNT);
1428                         if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1429                         else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1430                 }
1431                 app_loadmap = p2 ? p1 : 0;
1432                 ldso.loadmap = p2 ? p2 : p1;
1433                 ldso.base = laddr(&ldso, 0);
1434         } else {
1435                 ldso.base = base;
1436         }
1437         Ehdr *ehdr = (void *)ldso.base;
1438         ldso.name = ldso.shortname = "libc.so";
1439         ldso.phnum = ehdr->e_phnum;
1440         ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1441         ldso.phentsize = ehdr->e_phentsize;
1442         kernel_mapped_dso(&ldso);
1443         decode_dyn(&ldso);
1444
1445         if (DL_FDPIC) makefuncdescs(&ldso);
1446
1447         /* Prepare storage for to save clobbered REL addends so they
1448          * can be reused in stage 3. There should be very few. If
1449          * something goes wrong and there are a huge number, abort
1450          * instead of risking stack overflow. */
1451         size_t dyn[DYN_CNT];
1452         decode_vec(ldso.dynv, dyn, DYN_CNT);
1453         size_t *rel = laddr(&ldso, dyn[DT_REL]);
1454         size_t rel_size = dyn[DT_RELSZ];
1455         size_t symbolic_rel_cnt = 0;
1456         apply_addends_to = rel;
1457         for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1458                 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1459         if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1460         size_t addends[symbolic_rel_cnt+1];
1461         saved_addends = addends;
1462
1463         head = &ldso;
1464         reloc_all(&ldso);
1465
1466         ldso.relocated = 0;
1467
1468         /* Call dynamic linker stage-2b, __dls2b, looking it up
1469          * symbolically as a barrier against moving the address
1470          * load across the above relocation processing. */
1471         struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1472         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp);
1473         else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp);
1474 }
1475
1476 /* Stage 2b sets up a valid thread pointer, which requires relocations
1477  * completed in stage 2, and on which stage 3 is permitted to depend.
1478  * This is done as a separate stage, with symbolic lookup as a barrier,
1479  * so that loads of the thread pointer and &errno can be pure/const and
1480  * thereby hoistable. */
1481
1482 _Noreturn void __dls2b(size_t *sp)
1483 {
1484         /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1485          * use during dynamic linking. If possible it will also serve as the
1486          * thread pointer at runtime. */
1487         libc.tls_size = sizeof builtin_tls;
1488         libc.tls_align = tls_align;
1489         if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1490                 a_crash();
1491         }
1492
1493         struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1494         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1495         else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1496 }
1497
1498 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1499  * fully functional. Its job is to load (if not already loaded) and
1500  * process dependencies and relocations for the main application and
1501  * transfer control to its entry point. */
1502
1503 _Noreturn void __dls3(size_t *sp)
1504 {
1505         static struct dso app, vdso;
1506         size_t aux[AUX_CNT], *auxv;
1507         size_t i;
1508         char *env_preload=0;
1509         char *replace_argv0=0;
1510         size_t vdso_base;
1511         int argc = *sp;
1512         char **argv = (void *)(sp+1);
1513         char **argv_orig = argv;
1514         char **envp = argv+argc+1;
1515
1516         /* Find aux vector just past environ[] and use it to initialize
1517          * global data that may be needed before we can make syscalls. */
1518         __environ = envp;
1519         for (i=argc+1; argv[i]; i++);
1520         libc.auxv = auxv = (void *)(argv+i+1);
1521         decode_vec(auxv, aux, AUX_CNT);
1522         __hwcap = aux[AT_HWCAP];
1523         libc.page_size = aux[AT_PAGESZ];
1524         libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1525                 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1526
1527         /* Only trust user/env if kernel says we're not suid/sgid */
1528         if (!libc.secure) {
1529                 env_path = getenv("LD_LIBRARY_PATH");
1530                 env_preload = getenv("LD_PRELOAD");
1531         }
1532
1533         /* If the main program was already loaded by the kernel,
1534          * AT_PHDR will point to some location other than the dynamic
1535          * linker's program headers. */
1536         if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1537                 size_t interp_off = 0;
1538                 size_t tls_image = 0;
1539                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1540                 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1541                 app.phnum = aux[AT_PHNUM];
1542                 app.phentsize = aux[AT_PHENT];
1543                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1544                         if (phdr->p_type == PT_PHDR)
1545                                 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1546                         else if (phdr->p_type == PT_INTERP)
1547                                 interp_off = (size_t)phdr->p_vaddr;
1548                         else if (phdr->p_type == PT_TLS) {
1549                                 tls_image = phdr->p_vaddr;
1550                                 app.tls.len = phdr->p_filesz;
1551                                 app.tls.size = phdr->p_memsz;
1552                                 app.tls.align = phdr->p_align;
1553                         }
1554                 }
1555                 if (DL_FDPIC) app.loadmap = app_loadmap;
1556                 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1557                 if (interp_off) ldso.name = laddr(&app, interp_off);
1558                 if ((aux[0] & (1UL<<AT_EXECFN))
1559                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1560                         app.name = (char *)aux[AT_EXECFN];
1561                 else
1562                         app.name = argv[0];
1563                 kernel_mapped_dso(&app);
1564         } else {
1565                 int fd;
1566                 char *ldname = argv[0];
1567                 size_t l = strlen(ldname);
1568                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1569                 argv++;
1570                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1571                         char *opt = argv[0]+2;
1572                         *argv++ = (void *)-1;
1573                         if (!*opt) {
1574                                 break;
1575                         } else if (!memcmp(opt, "list", 5)) {
1576                                 ldd_mode = 1;
1577                         } else if (!memcmp(opt, "library-path", 12)) {
1578                                 if (opt[12]=='=') env_path = opt+13;
1579                                 else if (opt[12]) *argv = 0;
1580                                 else if (*argv) env_path = *argv++;
1581                         } else if (!memcmp(opt, "preload", 7)) {
1582                                 if (opt[7]=='=') env_preload = opt+8;
1583                                 else if (opt[7]) *argv = 0;
1584                                 else if (*argv) env_preload = *argv++;
1585                         } else if (!memcmp(opt, "argv0", 5)) {
1586                                 if (opt[5]=='=') replace_argv0 = opt+6;
1587                                 else if (opt[5]) *argv = 0;
1588                                 else if (*argv) replace_argv0 = *argv++;
1589                         } else {
1590                                 argv[0] = 0;
1591                         }
1592                 }
1593                 argv[-1] = (void *)(argc - (argv-argv_orig));
1594                 if (!argv[0]) {
1595                         dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1596                                 "Version %s\n"
1597                                 "Dynamic Program Loader\n"
1598                                 "Usage: %s [options] [--] pathname%s\n",
1599                                 __libc_version, ldname,
1600                                 ldd_mode ? "" : " [args]");
1601                         _exit(1);
1602                 }
1603                 fd = open(argv[0], O_RDONLY);
1604                 if (fd < 0) {
1605                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1606                         _exit(1);
1607                 }
1608                 Ehdr *ehdr = (void *)map_library(fd, &app);
1609                 if (!ehdr) {
1610                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1611                         _exit(1);
1612                 }
1613                 close(fd);
1614                 ldso.name = ldname;
1615                 app.name = argv[0];
1616                 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1617                 /* Find the name that would have been used for the dynamic
1618                  * linker had ldd not taken its place. */
1619                 if (ldd_mode) {
1620                         for (i=0; i<app.phnum; i++) {
1621                                 if (app.phdr[i].p_type == PT_INTERP)
1622                                         ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1623                         }
1624                         dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1625                 }
1626         }
1627         if (app.tls.size) {
1628                 libc.tls_head = tls_tail = &app.tls;
1629                 app.tls_id = tls_cnt = 1;
1630 #ifdef TLS_ABOVE_TP
1631                 app.tls.offset = GAP_ABOVE_TP;
1632                 app.tls.offset += -GAP_ABOVE_TP & (app.tls.align-1);
1633                 tls_offset = app.tls.offset + app.tls.size
1634                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1635                         & (app.tls.align-1) );
1636 #else
1637                 tls_offset = app.tls.offset = app.tls.size
1638                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1639                         & (app.tls.align-1) );
1640 #endif
1641                 tls_align = MAXP2(tls_align, app.tls.align);
1642         }
1643         decode_dyn(&app);
1644         if (DL_FDPIC) {
1645                 makefuncdescs(&app);
1646                 if (!app.loadmap) {
1647                         app.loadmap = (void *)&app_dummy_loadmap;
1648                         app.loadmap->nsegs = 1;
1649                         app.loadmap->segs[0].addr = (size_t)app.map;
1650                         app.loadmap->segs[0].p_vaddr = (size_t)app.map
1651                                 - (size_t)app.base;
1652                         app.loadmap->segs[0].p_memsz = app.map_len;
1653                 }
1654                 argv[-3] = (void *)app.loadmap;
1655         }
1656
1657         /* Initial dso chain consists only of the app. */
1658         head = tail = syms_tail = &app;
1659
1660         /* Donate unused parts of app and library mapping to malloc */
1661         reclaim_gaps(&app);
1662         reclaim_gaps(&ldso);
1663
1664         /* Load preload/needed libraries, add symbols to global namespace. */
1665         if (env_preload) load_preload(env_preload);
1666         load_deps(&app);
1667         for (struct dso *p=head; p; p=p->next)
1668                 add_syms(p);
1669
1670         /* Attach to vdso, if provided by the kernel, last so that it does
1671          * not become part of the global namespace.  */
1672         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1673                 Ehdr *ehdr = (void *)vdso_base;
1674                 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1675                 vdso.phnum = ehdr->e_phnum;
1676                 vdso.phentsize = ehdr->e_phentsize;
1677                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1678                         if (phdr->p_type == PT_DYNAMIC)
1679                                 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1680                         if (phdr->p_type == PT_LOAD)
1681                                 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1682                 }
1683                 vdso.name = "";
1684                 vdso.shortname = "linux-gate.so.1";
1685                 vdso.relocated = 1;
1686                 decode_dyn(&vdso);
1687                 vdso.prev = tail;
1688                 tail->next = &vdso;
1689                 tail = &vdso;
1690         }
1691
1692         for (i=0; app.dynv[i]; i+=2) {
1693                 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1694                         app.dynv[i+1] = (size_t)&debug;
1695                 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1696                         size_t *ptr = (size_t *) app.dynv[i+1];
1697                         *ptr = (size_t)&debug;
1698                 }
1699         }
1700
1701         /* The main program must be relocated LAST since it may contin
1702          * copy relocations which depend on libraries' relocations. */
1703         reloc_all(app.next);
1704         reloc_all(&app);
1705
1706         update_tls_size();
1707         if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1708                 void *initial_tls = calloc(libc.tls_size, 1);
1709                 if (!initial_tls) {
1710                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1711                                 argv[0], libc.tls_size);
1712                         _exit(127);
1713                 }
1714                 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1715                         a_crash();
1716                 }
1717         } else {
1718                 size_t tmp_tls_size = libc.tls_size;
1719                 pthread_t self = __pthread_self();
1720                 /* Temporarily set the tls size to the full size of
1721                  * builtin_tls so that __copy_tls will use the same layout
1722                  * as it did for before. Then check, just to be safe. */
1723                 libc.tls_size = sizeof builtin_tls;
1724                 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1725                 libc.tls_size = tmp_tls_size;
1726         }
1727         static_tls_cnt = tls_cnt;
1728
1729         if (ldso_fail) _exit(127);
1730         if (ldd_mode) _exit(0);
1731
1732         /* Determine if malloc was interposed by a replacement implementation
1733          * so that calloc and the memalign family can harden against the
1734          * possibility of incomplete replacement. */
1735         if (find_sym(head, "malloc", 1).dso != &ldso)
1736                 __malloc_replaced = 1;
1737
1738         /* Switch to runtime mode: any further failures in the dynamic
1739          * linker are a reportable failure rather than a fatal startup
1740          * error. */
1741         runtime = 1;
1742
1743         debug.ver = 1;
1744         debug.bp = dl_debug_state;
1745         debug.head = head;
1746         debug.base = ldso.base;
1747         debug.state = 0;
1748         _dl_debug_state();
1749
1750         if (replace_argv0) argv[0] = replace_argv0;
1751
1752         errno = 0;
1753
1754         CRTJMP((void *)aux[AT_ENTRY], argv-1);
1755         for(;;);
1756 }
1757
1758 static void prepare_lazy(struct dso *p)
1759 {
1760         size_t dyn[DYN_CNT], n, flags1=0;
1761         decode_vec(p->dynv, dyn, DYN_CNT);
1762         search_vec(p->dynv, &flags1, DT_FLAGS_1);
1763         if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1764                 return;
1765         n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1766         if (NEED_MIPS_GOT_RELOCS) {
1767                 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1768                 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1769                 n += i-j;
1770         }
1771         p->lazy = calloc(n, 3*sizeof(size_t));
1772         if (!p->lazy) {
1773                 error("Error preparing lazy relocation for %s: %m", p->name);
1774                 longjmp(*rtld_fail, 1);
1775         }
1776         p->lazy_next = lazy_head;
1777         lazy_head = p;
1778 }
1779
1780 void *dlopen(const char *file, int mode)
1781 {
1782         struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1783         struct tls_module *orig_tls_tail;
1784         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1785         size_t i;
1786         int cs;
1787         jmp_buf jb;
1788
1789         if (!file) return head;
1790
1791         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1792         pthread_rwlock_wrlock(&lock);
1793         __inhibit_ptc();
1794
1795         p = 0;
1796         orig_tls_tail = tls_tail;
1797         orig_tls_cnt = tls_cnt;
1798         orig_tls_offset = tls_offset;
1799         orig_tls_align = tls_align;
1800         orig_lazy_head = lazy_head;
1801         orig_syms_tail = syms_tail;
1802         orig_tail = tail;
1803         noload = mode & RTLD_NOLOAD;
1804
1805         rtld_fail = &jb;
1806         if (setjmp(*rtld_fail)) {
1807                 /* Clean up anything new that was (partially) loaded */
1808                 revert_syms(orig_syms_tail);
1809                 for (p=orig_tail->next; p; p=next) {
1810                         next = p->next;
1811                         while (p->td_index) {
1812                                 void *tmp = p->td_index->next;
1813                                 free(p->td_index);
1814                                 p->td_index = tmp;
1815                         }
1816                         free(p->funcdescs);
1817                         if (p->rpath != p->rpath_orig)
1818                                 free(p->rpath);
1819                         if (p->deps != &nodeps_dummy)
1820                                 free(p->deps);
1821                         unmap_library(p);
1822                         free(p);
1823                 }
1824                 if (!orig_tls_tail) libc.tls_head = 0;
1825                 tls_tail = orig_tls_tail;
1826                 if (tls_tail) tls_tail->next = 0;
1827                 tls_cnt = orig_tls_cnt;
1828                 tls_offset = orig_tls_offset;
1829                 tls_align = orig_tls_align;
1830                 lazy_head = orig_lazy_head;
1831                 tail = orig_tail;
1832                 tail->next = 0;
1833                 p = 0;
1834                 goto end;
1835         } else p = load_library(file, head);
1836
1837         if (!p) {
1838                 error(noload ?
1839                         "Library %s is not already loaded" :
1840                         "Error loading shared library %s: %m",
1841                         file);
1842                 goto end;
1843         }
1844
1845         /* First load handling */
1846         int first_load = !p->deps;
1847         if (first_load) {
1848                 load_deps(p);
1849                 if (!p->relocated && (mode & RTLD_LAZY)) {
1850                         prepare_lazy(p);
1851                         for (i=0; p->deps[i]; i++)
1852                                 if (!p->deps[i]->relocated)
1853                                         prepare_lazy(p->deps[i]);
1854                 }
1855         }
1856         if (first_load || (mode & RTLD_GLOBAL)) {
1857                 /* Make new symbols global, at least temporarily, so we can do
1858                  * relocations. If not RTLD_GLOBAL, this is reverted below. */
1859                 add_syms(p);
1860                 for (i=0; p->deps[i]; i++)
1861                         add_syms(p->deps[i]);
1862         }
1863         if (first_load) {
1864                 reloc_all(p);
1865         }
1866
1867         /* If RTLD_GLOBAL was not specified, undo any new additions
1868          * to the global symbol table. This is a nop if the library was
1869          * previously loaded and already global. */
1870         if (!(mode & RTLD_GLOBAL))
1871                 revert_syms(orig_syms_tail);
1872
1873         /* Processing of deferred lazy relocations must not happen until
1874          * the new libraries are committed; otherwise we could end up with
1875          * relocations resolved to symbol definitions that get removed. */
1876         redo_lazy_relocs();
1877
1878         update_tls_size();
1879         if (tls_cnt != orig_tls_cnt)
1880                 install_new_tls();
1881         _dl_debug_state();
1882         orig_tail = tail;
1883 end:
1884         __release_ptc();
1885         if (p) gencnt++;
1886         pthread_rwlock_unlock(&lock);
1887         if (p) do_init_fini(orig_tail);
1888         pthread_setcancelstate(cs, 0);
1889         return p;
1890 }
1891
1892 hidden int __dl_invalid_handle(void *h)
1893 {
1894         struct dso *p;
1895         for (p=head; p; p=p->next) if (h==p) return 0;
1896         error("Invalid library handle %p", (void *)h);
1897         return 1;
1898 }
1899
1900 static void *addr2dso(size_t a)
1901 {
1902         struct dso *p;
1903         size_t i;
1904         if (DL_FDPIC) for (p=head; p; p=p->next) {
1905                 i = count_syms(p);
1906                 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1907                         return p;
1908         }
1909         for (p=head; p; p=p->next) {
1910                 if (DL_FDPIC && p->loadmap) {
1911                         for (i=0; i<p->loadmap->nsegs; i++) {
1912                                 if (a-p->loadmap->segs[i].p_vaddr
1913                                     < p->loadmap->segs[i].p_memsz)
1914                                         return p;
1915                         }
1916                 } else {
1917                         Phdr *ph = p->phdr;
1918                         size_t phcnt = p->phnum;
1919                         size_t entsz = p->phentsize;
1920                         size_t base = (size_t)p->base;
1921                         for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
1922                                 if (ph->p_type != PT_LOAD) continue;
1923                                 if (a-base-ph->p_vaddr < ph->p_memsz)
1924                                         return p;
1925                         }
1926                         if (a-(size_t)p->map < p->map_len)
1927                                 return 0;
1928                 }
1929         }
1930         return 0;
1931 }
1932
1933 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1934 {
1935         size_t i;
1936         uint32_t h = 0, gh = 0, *ght;
1937         Sym *sym;
1938         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1939                 if (p == RTLD_DEFAULT) {
1940                         p = head;
1941                 } else if (p == RTLD_NEXT) {
1942                         p = addr2dso((size_t)ra);
1943                         if (!p) p=head;
1944                         p = p->next;
1945                 }
1946                 struct symdef def = find_sym(p, s, 0);
1947                 if (!def.sym) goto failed;
1948                 if ((def.sym->st_info&0xf) == STT_TLS)
1949                         return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
1950                 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1951                         return def.dso->funcdescs + (def.sym - def.dso->syms);
1952                 return laddr(def.dso, def.sym->st_value);
1953         }
1954         if (__dl_invalid_handle(p))
1955                 return 0;
1956         if ((ght = p->ghashtab)) {
1957                 gh = gnu_hash(s);
1958                 sym = gnu_lookup(gh, ght, p, s);
1959         } else {
1960                 h = sysv_hash(s);
1961                 sym = sysv_lookup(s, h, p);
1962         }
1963         if (sym && (sym->st_info&0xf) == STT_TLS)
1964                 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value-DTP_OFFSET});
1965         if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1966                 return p->funcdescs + (sym - p->syms);
1967         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1968                 return laddr(p, sym->st_value);
1969         for (i=0; p->deps[i]; i++) {
1970                 if ((ght = p->deps[i]->ghashtab)) {
1971                         if (!gh) gh = gnu_hash(s);
1972                         sym = gnu_lookup(gh, ght, p->deps[i], s);
1973                 } else {
1974                         if (!h) h = sysv_hash(s);
1975                         sym = sysv_lookup(s, h, p->deps[i]);
1976                 }
1977                 if (sym && (sym->st_info&0xf) == STT_TLS)
1978                         return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value-DTP_OFFSET});
1979                 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1980                         return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1981                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1982                         return laddr(p->deps[i], sym->st_value);
1983         }
1984 failed:
1985         error("Symbol not found: %s", s);
1986         return 0;
1987 }
1988
1989 int dladdr(const void *addr_arg, Dl_info *info)
1990 {
1991         size_t addr = (size_t)addr_arg;
1992         struct dso *p;
1993         Sym *sym, *bestsym;
1994         uint32_t nsym;
1995         char *strings;
1996         size_t best = 0;
1997         size_t besterr = -1;
1998
1999         pthread_rwlock_rdlock(&lock);
2000         p = addr2dso(addr);
2001         pthread_rwlock_unlock(&lock);
2002
2003         if (!p) return 0;
2004
2005         sym = p->syms;
2006         strings = p->strings;
2007         nsym = count_syms(p);
2008
2009         if (DL_FDPIC) {
2010                 size_t idx = (addr-(size_t)p->funcdescs)
2011                         / sizeof(*p->funcdescs);
2012                 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2013                         best = (size_t)(p->funcdescs + idx);
2014                         bestsym = sym + idx;
2015                         besterr = 0;
2016                 }
2017         }
2018
2019         if (!best) for (; nsym; nsym--, sym++) {
2020                 if (sym->st_value
2021                  && (1<<(sym->st_info&0xf) & OK_TYPES)
2022                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
2023                         size_t symaddr = (size_t)laddr(p, sym->st_value);
2024                         if (symaddr > addr || symaddr <= best)
2025                                 continue;
2026                         best = symaddr;
2027                         bestsym = sym;
2028                         besterr = addr - symaddr;
2029                         if (addr == symaddr)
2030                                 break;
2031                 }
2032         }
2033
2034         if (bestsym && besterr > bestsym->st_size-1) {
2035                 best = 0;
2036                 bestsym = 0;
2037         }
2038
2039         info->dli_fname = p->name;
2040         info->dli_fbase = p->map;
2041
2042         if (!best) {
2043                 info->dli_sname = 0;
2044                 info->dli_saddr = 0;
2045                 return 1;
2046         }
2047
2048         if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2049                 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2050         info->dli_sname = strings + bestsym->st_name;
2051         info->dli_saddr = (void *)best;
2052
2053         return 1;
2054 }
2055
2056 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2057 {
2058         void *res;
2059         pthread_rwlock_rdlock(&lock);
2060         res = do_dlsym(p, s, ra);
2061         pthread_rwlock_unlock(&lock);
2062         return res;
2063 }
2064
2065 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2066 {
2067         struct dso *current;
2068         struct dl_phdr_info info;
2069         int ret = 0;
2070         for(current = head; current;) {
2071                 info.dlpi_addr      = (uintptr_t)current->base;
2072                 info.dlpi_name      = current->name;
2073                 info.dlpi_phdr      = current->phdr;
2074                 info.dlpi_phnum     = current->phnum;
2075                 info.dlpi_adds      = gencnt;
2076                 info.dlpi_subs      = 0;
2077                 info.dlpi_tls_modid = current->tls_id;
2078                 info.dlpi_tls_data  = current->tls.image;
2079
2080                 ret = (callback)(&info, sizeof (info), data);
2081
2082                 if (ret != 0) break;
2083
2084                 pthread_rwlock_rdlock(&lock);
2085                 current = current->next;
2086                 pthread_rwlock_unlock(&lock);
2087         }
2088         return ret;
2089 }
2090
2091 static void error(const char *fmt, ...)
2092 {
2093         va_list ap;
2094         va_start(ap, fmt);
2095         if (!runtime) {
2096                 vdprintf(2, fmt, ap);
2097                 dprintf(2, "\n");
2098                 ldso_fail = 1;
2099                 va_end(ap);
2100                 return;
2101         }
2102         __dl_vseterr(fmt, ap);
2103         va_end(ap);
2104 }