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         char mark;
  75         char bfs_built;
  76         struct dso **deps, *needed_by;
  77         size_t ndeps_direct;
  78         char *rpath_orig, *rpath;
  79         struct tls_module tls;
  80         size_t tls_id;
  81         size_t relro_start, relro_end;
  82         uintptr_t *new_dtv;
  83         unsigned char *new_tls;
  84         volatile int new_dtv_idx, new_tls_idx;
  85         struct td_index *td_index;
  86         struct dso *fini_next;
  87         char *shortname;
  88 #if DL_FDPIC
  89         unsigned char *base;
  90 #else
  91         struct fdpic_loadmap *loadmap;
  92 #endif
  93         struct funcdesc {
  94                 void *addr;
  95                 size_t *got;
  96         } *funcdescs;
  97         size_t *got;
  98         char buf[];
  99 };
 100
 101 struct symdef {
 102         Sym *sym;
 103         struct dso *dso;
 104 };
 105
 106 static struct builtin_tls {
 107         char c;
 108         struct pthread pt;
 109         void *space[16];
 110 } builtin_tls[1];
 111 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
 112
 113 #define ADDEND_LIMIT 4096
 114 static size_t *saved_addends, *apply_addends_to;
 115
 116 static struct dso ldso;
 117 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
 118 static char *env_path, *sys_path;
 119 static unsigned long long gencnt;
 120 static int runtime;
 121 static int ldd_mode;
 122 static int ldso_fail;
 123 static int noload;
 124 static jmp_buf *rtld_fail;
 125 static pthread_rwlock_t lock;
 126 static struct debug debug;
 127 static struct tls_module *tls_tail;
 128 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
 129 static size_t static_tls_cnt;
 130 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 131 static struct fdpic_loadmap *app_loadmap;
 132 static struct fdpic_dummy_loadmap app_dummy_loadmap;
 133
 134 struct debug *_dl_debug_addr = &debug;
 135
 136 extern hidden int __malloc_replaced;
 137
 138 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
 139
 140 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
 141
 142 weak_alias(__init_array_start, __init_array_end);
 143 weak_alias(__fini_array_start, __fini_array_end);
 144
 145 static int dl_strcmp(const char *l, const char *r)
 146 {
 147         for (; *l==*r && *l; l++, r++);
 148         return *(unsigned char *)l - *(unsigned char *)r;
 149 }
 150 #define strcmp(l,r) dl_strcmp(l,r)
 151
 152 /* Compute load address for a virtual address in a given dso. */
 153 #if DL_FDPIC
 154 static void *laddr(const struct dso *p, size_t v)
 155 {
 156         size_t j=0;
 157         if (!p->loadmap) return p->base + v;
 158         for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
 159         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 160 }
 161 static void *laddr_pg(const struct dso *p, size_t v)
 162 {
 163         size_t j=0;
 164         size_t pgsz = PAGE_SIZE;
 165         if (!p->loadmap) return p->base + v;
 166         for (j=0; ; j++) {
 167                 size_t a = p->loadmap->segs[j].p_vaddr;
 168                 size_t b = a + p->loadmap->segs[j].p_memsz;
 169                 a &= -pgsz;
 170                 b += pgsz-1;
 171                 b &= -pgsz;
 172                 if (v-a<b-a) break;
 173         }
 174         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 175 }
 176 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
 177         laddr(p, v), (p)->got })
 178 #else
 179 #define laddr(p, v) (void *)((p)->base + (v))
 180 #define laddr_pg(p, v) laddr(p, v)
 181 #define fpaddr(p, v) ((void (*)())laddr(p, v))
 182 #endif
 183
 184 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 185 {
 186         size_t i;
 187         for (i=0; i<cnt; i++) a[i] = 0;
 188         for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
 189                 a[0] |= 1UL<<v[0];
 190                 a[v[0]] = v[1];
 191         }
 192 }
 193
 194 static int search_vec(size_t *v, size_t *r, size_t key)
 195 {
 196         for (; v[0]!=key; v+=2)
 197                 if (!v[0]) return 0;
 198         *r = v[1];
 199         return 1;
 200 }
 201
 202 static uint32_t sysv_hash(const char *s0)
 203 {
 204         const unsigned char *s = (void *)s0;
 205         uint_fast32_t h = 0;
 206         while (*s) {
 207                 h = 16*h + *s++;
 208                 h ^= h>>24 & 0xf0;
 209         }
 210         return h & 0xfffffff;
 211 }
 212
 213 static uint32_t gnu_hash(const char *s0)
 214 {
 215         const unsigned char *s = (void *)s0;
 216         uint_fast32_t h = 5381;
 217         for (; *s; s++)
 218                 h += h*32 + *s;
 219         return h;
 220 }
 221
 222 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 223 {
 224         size_t i;
 225         Sym *syms = dso->syms;
 226         Elf_Symndx *hashtab = dso->hashtab;
 227         char *strings = dso->strings;
 228         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 229                 if ((!dso->versym || dso->versym[i] >= 0)
 230                     && (!strcmp(s, strings+syms[i].st_name)))
 231                         return syms+i;
 232         }
 233         return 0;
 234 }
 235
 236 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
 237 {
 238         uint32_t nbuckets = hashtab[0];
 239         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 240         uint32_t i = buckets[h1 % nbuckets];
 241
 242         if (!i) return 0;
 243
 244         uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
 245
 246         for (h1 |= 1; ; i++) {
 247                 uint32_t h2 = *hashval++;
 248                 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
 249                     && !strcmp(s, dso->strings + dso->syms[i].st_name))
 250                         return dso->syms+i;
 251                 if (h2 & 1) break;
 252         }
 253
 254         return 0;
 255 }
 256
 257 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
 258 {
 259         const size_t *bloomwords = (const void *)(hashtab+4);
 260         size_t f = bloomwords[fofs & (hashtab[2]-1)];
 261         if (!(f & fmask)) return 0;
 262
 263         f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
 264         if (!(f & 1)) return 0;
 265
 266         return gnu_lookup(h1, hashtab, dso, s);
 267 }
 268
 269 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 270 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 271
 272 #ifndef ARCH_SYM_REJECT_UND
 273 #define ARCH_SYM_REJECT_UND(s) 0
 274 #endif
 275
 276 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 277 {
 278         uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
 279         size_t ghm = 1ul << gh % (8*sizeof(size_t));
 280         struct symdef def = {0};
 281         for (; dso; dso=dso->syms_next) {
 282                 Sym *sym;
 283                 if ((ght = dso->ghashtab)) {
 284                         sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
 285                 } else {
 286                         if (!h) h = sysv_hash(s);
 287                         sym = sysv_lookup(s, h, dso);
 288                 }
 289                 if (!sym) continue;
 290                 if (!sym->st_shndx)
 291                         if (need_def || (sym->st_info&0xf) == STT_TLS
 292                             || ARCH_SYM_REJECT_UND(sym))
 293                                 continue;
 294                 if (!sym->st_value)
 295                         if ((sym->st_info&0xf) != STT_TLS)
 296                                 continue;
 297                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 298                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 299                 def.sym = sym;
 300                 def.dso = dso;
 301                 break;
 302         }
 303         return def;
 304 }
 305
 306 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 307 {
 308         unsigned char *base = dso->base;
 309         Sym *syms = dso->syms;
 310         char *strings = dso->strings;
 311         Sym *sym;
 312         const char *name;
 313         void *ctx;
 314         int type;
 315         int sym_index;
 316         struct symdef def;
 317         size_t *reloc_addr;
 318         size_t sym_val;
 319         size_t tls_val;
 320         size_t addend;
 321         int skip_relative = 0, reuse_addends = 0, save_slot = 0;
 322
 323         if (dso == &ldso) {
 324                 /* Only ldso's REL table needs addend saving/reuse. */
 325                 if (rel == apply_addends_to)
 326                         reuse_addends = 1;
 327                 skip_relative = 1;
 328         }
 329
 330         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 331                 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
 332                 type = R_TYPE(rel[1]);
 333                 if (type == REL_NONE) continue;
 334                 reloc_addr = laddr(dso, rel[0]);
 335
 336                 if (stride > 2) {
 337                         addend = rel[2];
 338                 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
 339                         addend = 0;
 340                 } else if (reuse_addends) {
 341                         /* Save original addend in stage 2 where the dso
 342                          * chain consists of just ldso; otherwise read back
 343                          * saved addend since the inline one was clobbered. */
 344                         if (head==&ldso)
 345                                 saved_addends[save_slot] = *reloc_addr;
 346                         addend = saved_addends[save_slot++];
 347                 } else {
 348                         addend = *reloc_addr;
 349                 }
 350
 351                 sym_index = R_SYM(rel[1]);
 352                 if (sym_index) {
 353                         sym = syms + sym_index;
 354                         name = strings + sym->st_name;
 355                         ctx = type==REL_COPY ? head->syms_next : head;
 356                         def = (sym->st_info&0xf) == STT_SECTION
 357                                 ? (struct symdef){ .dso = dso, .sym = sym }
 358                                 : find_sym(ctx, name, type==REL_PLT);
 359                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 360                             || sym->st_info>>4 != STB_WEAK)) {
 361                                 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
 362                                         dso->lazy[3*dso->lazy_cnt+0] = rel[0];
 363                                         dso->lazy[3*dso->lazy_cnt+1] = rel[1];
 364                                         dso->lazy[3*dso->lazy_cnt+2] = addend;
 365                                         dso->lazy_cnt++;
 366                                         continue;
 367                                 }
 368                                 error("Error relocating %s: %s: symbol not found",
 369                                         dso->name, name);
 370                                 if (runtime) longjmp(*rtld_fail, 1);
 371                                 continue;
 372                         }
 373                 } else {
 374                         sym = 0;
 375                         def.sym = 0;
 376                         def.dso = dso;
 377                 }
 378
 379                 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
 380                 tls_val = def.sym ? def.sym->st_value : 0;
 381
 382                 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
 383                     && runtime && def.dso->tls_id > static_tls_cnt) {
 384                         error("Error relocating %s: %s: initial-exec TLS "
 385                                 "resolves to dynamic definition in %s",
 386                                 dso->name, name, def.dso->name);
 387                         longjmp(*rtld_fail, 1);
 388                 }
 389
 390                 switch(type) {
 391                 case REL_NONE:
 392                         break;
 393                 case REL_OFFSET:
 394                         addend -= (size_t)reloc_addr;
 395                 case REL_SYMBOLIC:
 396                 case REL_GOT:
 397                 case REL_PLT:
 398                         *reloc_addr = sym_val + addend;
 399                         break;
 400                 case REL_RELATIVE:
 401                         *reloc_addr = (size_t)base + addend;
 402                         break;
 403                 case REL_SYM_OR_REL:
 404                         if (sym) *reloc_addr = sym_val + addend;
 405                         else *reloc_addr = (size_t)base + addend;
 406                         break;
 407                 case REL_COPY:
 408                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 409                         break;
 410                 case REL_OFFSET32:
 411                         *(uint32_t *)reloc_addr = sym_val + addend
 412                                 - (size_t)reloc_addr;
 413                         break;
 414                 case REL_FUNCDESC:
 415                         *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
 416                                 + (def.sym - def.dso->syms)) : 0;
 417                         break;
 418                 case REL_FUNCDESC_VAL:
 419                         if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
 420                         else *reloc_addr = sym_val;
 421                         reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
 422                         break;
 423                 case REL_DTPMOD:
 424                         *reloc_addr = def.dso->tls_id;
 425                         break;
 426                 case REL_DTPOFF:
 427                         *reloc_addr = tls_val + addend - DTP_OFFSET;
 428                         break;
 429 #ifdef TLS_ABOVE_TP
 430                 case REL_TPOFF:
 431                         *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
 432                         break;
 433 #else
 434                 case REL_TPOFF:
 435                         *reloc_addr = tls_val - def.dso->tls.offset + addend;
 436                         break;
 437                 case REL_TPOFF_NEG:
 438                         *reloc_addr = def.dso->tls.offset - tls_val + addend;
 439                         break;
 440 #endif
 441                 case REL_TLSDESC:
 442                         if (stride<3) addend = reloc_addr[1];
 443                         if (runtime && def.dso->tls_id > static_tls_cnt) {
 444                                 struct td_index *new = malloc(sizeof *new);
 445                                 if (!new) {
 446                                         error(
 447                                         "Error relocating %s: cannot allocate TLSDESC for %s",
 448                                         dso->name, sym ? name : "(local)" );
 449                                         longjmp(*rtld_fail, 1);
 450                                 }
 451                                 new->next = dso->td_index;
 452                                 dso->td_index = new;
 453                                 new->args[0] = def.dso->tls_id;
 454                                 new->args[1] = tls_val + addend - DTP_OFFSET;
 455                                 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
 456                                 reloc_addr[1] = (size_t)new;
 457                         } else {
 458                                 reloc_addr[0] = (size_t)__tlsdesc_static;
 459 #ifdef TLS_ABOVE_TP
 460                                 reloc_addr[1] = tls_val + def.dso->tls.offset
 461                                         + TPOFF_K + addend;
 462 #else
 463                                 reloc_addr[1] = tls_val - def.dso->tls.offset
 464                                         + addend;
 465 #endif
 466                         }
 467 #ifdef TLSDESC_BACKWARDS
 468                         /* Some archs (32-bit ARM at least) invert the order of
 469                          * the descriptor members. Fix them up here. */
 470                         size_t tmp = reloc_addr[0];
 471                         reloc_addr[0] = reloc_addr[1];
 472                         reloc_addr[1] = tmp;
 473 #endif
 474                         break;
 475                 default:
 476                         error("Error relocating %s: unsupported relocation type %d",
 477                                 dso->name, type);
 478                         if (runtime) longjmp(*rtld_fail, 1);
 479                         continue;
 480                 }
 481         }
 482 }
 483
 484 static void redo_lazy_relocs()
 485 {
 486         struct dso *p = lazy_head, *next;
 487         lazy_head = 0;
 488         for (; p; p=next) {
 489                 next = p->lazy_next;
 490                 size_t size = p->lazy_cnt*3*sizeof(size_t);
 491                 p->lazy_cnt = 0;
 492                 do_relocs(p, p->lazy, size, 3);
 493                 if (p->lazy_cnt) {
 494                         p->lazy_next = lazy_head;
 495                         lazy_head = p;
 496                 } else {
 497                         free(p->lazy);
 498                         p->lazy = 0;
 499                         p->lazy_next = 0;
 500                 }
 501         }
 502 }
 503
 504 /* A huge hack: to make up for the wastefulness of shared libraries
 505  * needing at least a page of dirty memory even if they have no global
 506  * data, we reclaim the gaps at the beginning and end of writable maps
 507  * and "donate" them to the heap. */
 508
 509 static void reclaim(struct dso *dso, size_t start, size_t end)
 510 {
 511         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 512         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 513         if (start >= end) return;
 514         char *base = laddr_pg(dso, start);
 515         __malloc_donate(base, base+(end-start));
 516 }
 517
 518 static void reclaim_gaps(struct dso *dso)
 519 {
 520         Phdr *ph = dso->phdr;
 521         size_t phcnt = dso->phnum;
 522
 523         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 524                 if (ph->p_type!=PT_LOAD) continue;
 525                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 526                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 527                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 528                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 529         }
 530 }
 531
 532 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
 533 {
 534         static int no_map_fixed;
 535         char *q;
 536         if (!no_map_fixed) {
 537                 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
 538                 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
 539                         return q;
 540                 no_map_fixed = 1;
 541         }
 542         /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
 543         if (flags & MAP_ANONYMOUS) {
 544                 memset(p, 0, n);
 545                 return p;
 546         }
 547         ssize_t r;
 548         if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
 549         for (q=p; n; q+=r, off+=r, n-=r) {
 550                 r = read(fd, q, n);
 551                 if (r < 0 && errno != EINTR) return MAP_FAILED;
 552                 if (!r) {
 553                         memset(q, 0, n);
 554                         break;
 555                 }
 556         }
 557         return p;
 558 }
 559
 560 static void unmap_library(struct dso *dso)
 561 {
 562         if (dso->loadmap) {
 563                 size_t i;
 564                 for (i=0; i<dso->loadmap->nsegs; i++) {
 565                         if (!dso->loadmap->segs[i].p_memsz)
 566                                 continue;
 567                         munmap((void *)dso->loadmap->segs[i].addr,
 568                                 dso->loadmap->segs[i].p_memsz);
 569                 }
 570                 free(dso->loadmap);
 571         } else if (dso->map && dso->map_len) {
 572                 munmap(dso->map, dso->map_len);
 573         }
 574 }
 575
 576 static void *map_library(int fd, struct dso *dso)
 577 {
 578         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 579         void *allocated_buf=0;
 580         size_t phsize;
 581         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 582         size_t this_min, this_max;
 583         size_t nsegs = 0;
 584         off_t off_start;
 585         Ehdr *eh;
 586         Phdr *ph, *ph0;
 587         unsigned prot;
 588         unsigned char *map=MAP_FAILED, *base;
 589         size_t dyn=0;
 590         size_t tls_image=0;
 591         size_t i;
 592
 593         ssize_t l = read(fd, buf, sizeof buf);
 594         eh = buf;
 595         if (l<0) return 0;
 596         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 597                 goto noexec;
 598         phsize = eh->e_phentsize * eh->e_phnum;
 599         if (phsize > sizeof buf - sizeof *eh) {
 600                 allocated_buf = malloc(phsize);
 601                 if (!allocated_buf) return 0;
 602                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 603                 if (l < 0) goto error;
 604                 if (l != phsize) goto noexec;
 605                 ph = ph0 = allocated_buf;
 606         } else if (eh->e_phoff + phsize > l) {
 607                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 608                 if (l < 0) goto error;
 609                 if (l != phsize) goto noexec;
 610                 ph = ph0 = (void *)(buf + 1);
 611         } else {
 612                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 613         }
 614         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 615                 if (ph->p_type == PT_DYNAMIC) {
 616                         dyn = ph->p_vaddr;
 617                 } else if (ph->p_type == PT_TLS) {
 618                         tls_image = ph->p_vaddr;
 619                         dso->tls.align = ph->p_align;
 620                         dso->tls.len = ph->p_filesz;
 621                         dso->tls.size = ph->p_memsz;
 622                 } else if (ph->p_type == PT_GNU_RELRO) {
 623                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 624                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 625                 } else if (ph->p_type == PT_GNU_STACK) {
 626                         if (!runtime && ph->p_memsz > __default_stacksize) {
 627                                 __default_stacksize =
 628                                         ph->p_memsz < DEFAULT_STACK_MAX ?
 629                                         ph->p_memsz : DEFAULT_STACK_MAX;
 630                         }
 631                 }
 632                 if (ph->p_type != PT_LOAD) continue;
 633                 nsegs++;
 634                 if (ph->p_vaddr < addr_min) {
 635                         addr_min = ph->p_vaddr;
 636                         off_start = ph->p_offset;
 637                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 638                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 639                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 640                 }
 641                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 642                         addr_max = ph->p_vaddr+ph->p_memsz;
 643                 }
 644         }
 645         if (!dyn) goto noexec;
 646         if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
 647                 dso->loadmap = calloc(1, sizeof *dso->loadmap
 648                         + nsegs * sizeof *dso->loadmap->segs);
 649                 if (!dso->loadmap) goto error;
 650                 dso->loadmap->nsegs = nsegs;
 651                 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
 652                         if (ph->p_type != PT_LOAD) continue;
 653                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 654                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 655                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 656                         map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
 657                                 prot, MAP_PRIVATE,
 658                                 fd, ph->p_offset & -PAGE_SIZE);
 659                         if (map == MAP_FAILED) {
 660                                 unmap_library(dso);
 661                                 goto error;
 662                         }
 663                         dso->loadmap->segs[i].addr = (size_t)map +
 664                                 (ph->p_vaddr & PAGE_SIZE-1);
 665                         dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
 666                         dso->loadmap->segs[i].p_memsz = ph->p_memsz;
 667                         i++;
 668                         if (prot & PROT_WRITE) {
 669                                 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
 670                                         + ph->p_filesz;
 671                                 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
 672                                 size_t pgend = brk + ph->p_memsz - ph->p_filesz
 673                                         + PAGE_SIZE-1 & -PAGE_SIZE;
 674                                 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
 675                                         pgend-pgbrk, prot,
 676                                         MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
 677                                         -1, off_start) == MAP_FAILED)
 678                                         goto error;
 679                                 memset(map + brk, 0, pgbrk-brk);
 680                         }
 681                 }
 682                 map = (void *)dso->loadmap->segs[0].addr;
 683                 map_len = 0;
 684                 goto done_mapping;
 685         }
 686         addr_max += PAGE_SIZE-1;
 687         addr_max &= -PAGE_SIZE;
 688         addr_min &= -PAGE_SIZE;
 689         off_start &= -PAGE_SIZE;
 690         map_len = addr_max - addr_min + off_start;
 691         /* The first time, we map too much, possibly even more than
 692          * the length of the file. This is okay because we will not
 693          * use the invalid part; we just need to reserve the right
 694          * amount of virtual address space to map over later. */
 695         map = DL_NOMMU_SUPPORT
 696                 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
 697                         MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
 698                 : mmap((void *)addr_min, map_len, prot,
 699                         MAP_PRIVATE, fd, off_start);
 700         if (map==MAP_FAILED) goto error;
 701         dso->map = map;
 702         dso->map_len = map_len;
 703         /* If the loaded file is not relocatable and the requested address is
 704          * not available, then the load operation must fail. */
 705         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 706                 errno = EBUSY;
 707                 goto error;
 708         }
 709         base = map - addr_min;
 710         dso->phdr = 0;
 711         dso->phnum = 0;
 712         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 713                 if (ph->p_type != PT_LOAD) continue;
 714                 /* Check if the programs headers are in this load segment, and
 715                  * if so, record the address for use by dl_iterate_phdr. */
 716                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 717                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 718                         dso->phdr = (void *)(base + ph->p_vaddr
 719                                 + (eh->e_phoff-ph->p_offset));
 720                         dso->phnum = eh->e_phnum;
 721                         dso->phentsize = eh->e_phentsize;
 722                 }
 723                 this_min = ph->p_vaddr & -PAGE_SIZE;
 724                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 725                 off_start = ph->p_offset & -PAGE_SIZE;
 726                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 727                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 728                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 729                 /* Reuse the existing mapping for the lowest-address LOAD */
 730                 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
 731                         if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 732                                 goto error;
 733                 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
 734                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 735                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 736                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 737                         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)
 738                                 goto error;
 739                 }
 740         }
 741         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 742                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 743                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
 744                             && errno != ENOSYS)
 745                                 goto error;
 746                         break;
 747                 }
 748 done_mapping:
 749         dso->base = base;
 750         dso->dynv = laddr(dso, dyn);
 751         if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
 752         free(allocated_buf);
 753         return map;
 754 noexec:
 755         errno = ENOEXEC;
 756 error:
 757         if (map!=MAP_FAILED) unmap_library(dso);
 758         free(allocated_buf);
 759         return 0;
 760 }
 761
 762 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 763 {
 764         size_t l;
 765         int fd;
 766         for (;;) {
 767                 s += strspn(s, ":\n");
 768                 l = strcspn(s, ":\n");
 769                 if (l-1 >= INT_MAX) return -1;
 770                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
 771                         if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 772                         switch (errno) {
 773                         case ENOENT:
 774                         case ENOTDIR:
 775                         case EACCES:
 776                         case ENAMETOOLONG:
 777                                 break;
 778                         default:
 779                                 /* Any negative value but -1 will inhibit
 780                                  * futher path search. */
 781                                 return -2;
 782                         }
 783                 }
 784                 s += l;
 785         }
 786 }
 787
 788 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 789 {
 790         size_t n, l;
 791         const char *s, *t, *origin;
 792         char *d;
 793         if (p->rpath || !p->rpath_orig) return 0;
 794         if (!strchr(p->rpath_orig, '$')) {
 795                 p->rpath = p->rpath_orig;
 796                 return 0;
 797         }
 798         n = 0;
 799         s = p->rpath_orig;
 800         while ((t=strchr(s, '$'))) {
 801                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 802                         return 0;
 803                 s = t+1;
 804                 n++;
 805         }
 806         if (n > SSIZE_MAX/PATH_MAX) return 0;
 807
 808         if (p->kernel_mapped) {
 809                 /* $ORIGIN searches cannot be performed for the main program
 810                  * when it is suid/sgid/AT_SECURE. This is because the
 811                  * pathname is under the control of the caller of execve.
 812                  * For libraries, however, $ORIGIN can be processed safely
 813                  * since the library's pathname came from a trusted source
 814                  * (either system paths or a call to dlopen). */
 815                 if (libc.secure)
 816                         return 0;
 817                 l = readlink("/proc/self/exe", buf, buf_size);
 818                 if (l == -1) switch (errno) {
 819                 case ENOENT:
 820                 case ENOTDIR:
 821                 case EACCES:
 822                         break;
 823                 default:
 824                         return -1;
 825                 }
 826                 if (l >= buf_size)
 827                         return 0;
 828                 buf[l] = 0;
 829                 origin = buf;
 830         } else {
 831                 origin = p->name;
 832         }
 833         t = strrchr(origin, '/');
 834         if (t) {
 835                 l = t-origin;
 836         } else {
 837                 /* Normally p->name will always be an absolute or relative
 838                  * pathname containing at least one '/' character, but in the
 839                  * case where ldso was invoked as a command to execute a
 840                  * program in the working directory, app.name may not. Fix. */
 841                 origin = ".";
 842                 l = 1;
 843         }
 844         /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
 845         if (libc.secure && *origin != '/')
 846                 return 0;
 847         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 848         if (!p->rpath) return -1;
 849
 850         d = p->rpath;
 851         s = p->rpath_orig;
 852         while ((t=strchr(s, '$'))) {
 853                 memcpy(d, s, t-s);
 854                 d += t-s;
 855                 memcpy(d, origin, l);
 856                 d += l;
 857                 /* It was determined previously that the '$' is followed
 858                  * either by "ORIGIN" or "{ORIGIN}". */
 859                 s = t + 7 + 2*(t[1]=='{');
 860         }
 861         strcpy(d, s);
 862         return 0;
 863 }
 864
 865 static void decode_dyn(struct dso *p)
 866 {
 867         size_t dyn[DYN_CNT];
 868         decode_vec(p->dynv, dyn, DYN_CNT);
 869         p->syms = laddr(p, dyn[DT_SYMTAB]);
 870         p->strings = laddr(p, dyn[DT_STRTAB]);
 871         if (dyn[0]&(1<<DT_HASH))
 872                 p->hashtab = laddr(p, dyn[DT_HASH]);
 873         if (dyn[0]&(1<<DT_RPATH))
 874                 p->rpath_orig = p->strings + dyn[DT_RPATH];
 875         if (dyn[0]&(1<<DT_RUNPATH))
 876                 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
 877         if (dyn[0]&(1<<DT_PLTGOT))
 878                 p->got = laddr(p, dyn[DT_PLTGOT]);
 879         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 880                 p->ghashtab = laddr(p, *dyn);
 881         if (search_vec(p->dynv, dyn, DT_VERSYM))
 882                 p->versym = laddr(p, *dyn);
 883 }
 884
 885 static size_t count_syms(struct dso *p)
 886 {
 887         if (p->hashtab) return p->hashtab[1];
 888
 889         size_t nsym, i;
 890         uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
 891         uint32_t *hashval;
 892         for (i = nsym = 0; i < p->ghashtab[0]; i++) {
 893                 if (buckets[i] > nsym)
 894                         nsym = buckets[i];
 895         }
 896         if (nsym) {
 897                 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
 898                 do nsym++;
 899                 while (!(*hashval++ & 1));
 900         }
 901         return nsym;
 902 }
 903
 904 static void *dl_mmap(size_t n)
 905 {
 906         void *p;
 907         int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
 908 #ifdef SYS_mmap2
 909         p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
 910 #else
 911         p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
 912 #endif
 913         return p == MAP_FAILED ? 0 : p;
 914 }
 915
 916 static void makefuncdescs(struct dso *p)
 917 {
 918         static int self_done;
 919         size_t nsym = count_syms(p);
 920         size_t i, size = nsym * sizeof(*p->funcdescs);
 921
 922         if (!self_done) {
 923                 p->funcdescs = dl_mmap(size);
 924                 self_done = 1;
 925         } else {
 926                 p->funcdescs = malloc(size);
 927         }
 928         if (!p->funcdescs) {
 929                 if (!runtime) a_crash();
 930                 error("Error allocating function descriptors for %s", p->name);
 931                 longjmp(*rtld_fail, 1);
 932         }
 933         for (i=0; i<nsym; i++) {
 934                 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
 935                         p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
 936                         p->funcdescs[i].got = p->got;
 937                 } else {
 938                         p->funcdescs[i].addr = 0;
 939                         p->funcdescs[i].got = 0;
 940                 }
 941         }
 942 }
 943
 944 static struct dso *load_library(const char *name, struct dso *needed_by)
 945 {
 946         char buf[2*NAME_MAX+2];
 947         const char *pathname;
 948         unsigned char *map;
 949         struct dso *p, temp_dso = {0};
 950         int fd;
 951         struct stat st;
 952         size_t alloc_size;
 953         int n_th = 0;
 954         int is_self = 0;
 955
 956         if (!*name) {
 957                 errno = EINVAL;
 958                 return 0;
 959         }
 960
 961         /* Catch and block attempts to reload the implementation itself */
 962         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 963                 static const char reserved[] =
 964                         "c.pthread.rt.m.dl.util.xnet.";
 965                 const char *rp, *next;
 966                 for (rp=reserved; *rp; rp=next) {
 967                         next = strchr(rp, '.') + 1;
 968                         if (strncmp(name+3, rp, next-rp) == 0)
 969                                 break;
 970                 }
 971                 if (*rp) {
 972                         if (ldd_mode) {
 973                                 /* Track which names have been resolved
 974                                  * and only report each one once. */
 975                                 static unsigned reported;
 976                                 unsigned mask = 1U<<(rp-reserved);
 977                                 if (!(reported & mask)) {
 978                                         reported |= mask;
 979                                         dprintf(1, "\t%s => %s (%p)\n",
 980                                                 name, ldso.name,
 981                                                 ldso.base);
 982                                 }
 983                         }
 984                         is_self = 1;
 985                 }
 986         }
 987         if (!strcmp(name, ldso.name)) is_self = 1;
 988         if (is_self) {
 989                 if (!ldso.prev) {
 990                         tail->next = &ldso;
 991                         ldso.prev = tail;
 992                         tail = &ldso;
 993                 }
 994                 return &ldso;
 995         }
 996         if (strchr(name, '/')) {
 997                 pathname = name;
 998                 fd = open(name, O_RDONLY|O_CLOEXEC);
 999         } else {
1000                 /* Search for the name to see if it's already loaded */
1001                 for (p=head->next; p; p=p->next) {
1002                         if (p->shortname && !strcmp(p->shortname, name)) {
1003                                 return p;
1004                         }
1005                 }
1006                 if (strlen(name) > NAME_MAX) return 0;
1007                 fd = -1;
1008                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1009                 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1010                         if (fixup_rpath(p, buf, sizeof buf) < 0)
1011                                 fd = -2; /* Inhibit further search. */
1012                         if (p->rpath)
1013                                 fd = path_open(name, p->rpath, buf, sizeof buf);
1014                 }
1015                 if (fd == -1) {
1016                         if (!sys_path) {
1017                                 char *prefix = 0;
1018                                 size_t prefix_len;
1019                                 if (ldso.name[0]=='/') {
1020                                         char *s, *t, *z;
1021                                         for (s=t=z=ldso.name; *s; s++)
1022                                                 if (*s=='/') z=t, t=s;
1023                                         prefix_len = z-ldso.name;
1024                                         if (prefix_len < PATH_MAX)
1025                                                 prefix = ldso.name;
1026                                 }
1027                                 if (!prefix) {
1028                                         prefix = "";
1029                                         prefix_len = 0;
1030                                 }
1031                                 char etc_ldso_path[prefix_len + 1
1032                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1033                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1034                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1035                                         (int)prefix_len, prefix);
1036                                 FILE *f = fopen(etc_ldso_path, "rbe");
1037                                 if (f) {
1038                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1039                                                 free(sys_path);
1040                                                 sys_path = "";
1041                                         }
1042                                         fclose(f);
1043                                 } else if (errno != ENOENT) {
1044                                         sys_path = "";
1045                                 }
1046                         }
1047                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1048                         fd = path_open(name, sys_path, buf, sizeof buf);
1049                 }
1050                 pathname = buf;
1051         }
1052         if (fd < 0) return 0;
1053         if (fstat(fd, &st) < 0) {
1054                 close(fd);
1055                 return 0;
1056         }
1057         for (p=head->next; p; p=p->next) {
1058                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1059                         /* If this library was previously loaded with a
1060                          * pathname but a search found the same inode,
1061                          * setup its shortname so it can be found by name. */
1062                         if (!p->shortname && pathname != name)
1063                                 p->shortname = strrchr(p->name, '/')+1;
1064                         close(fd);
1065                         return p;
1066                 }
1067         }
1068         map = noload ? 0 : map_library(fd, &temp_dso);
1069         close(fd);
1070         if (!map) return 0;
1071
1072         /* Avoid the danger of getting two versions of libc mapped into the
1073          * same process when an absolute pathname was used. The symbols
1074          * checked are chosen to catch both musl and glibc, and to avoid
1075          * false positives from interposition-hack libraries. */
1076         decode_dyn(&temp_dso);
1077         if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1078             find_sym(&temp_dso, "stdin", 1).sym) {
1079                 unmap_library(&temp_dso);
1080                 return load_library("libc.so", needed_by);
1081         }
1082         /* Past this point, if we haven't reached runtime yet, ldso has
1083          * committed either to use the mapped library or to abort execution.
1084          * Unmapping is not possible, so we can safely reclaim gaps. */
1085         if (!runtime) reclaim_gaps(&temp_dso);
1086
1087         /* Allocate storage for the new DSO. When there is TLS, this
1088          * storage must include a reservation for all pre-existing
1089          * threads to obtain copies of both the new TLS, and an
1090          * extended DTV capable of storing an additional slot for
1091          * the newly-loaded DSO. */
1092         alloc_size = sizeof *p + strlen(pathname) + 1;
1093         if (runtime && temp_dso.tls.image) {
1094                 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1095                         + sizeof(void *) * (tls_cnt+3);
1096                 n_th = libc.threads_minus_1 + 1;
1097                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1098                 else alloc_size += n_th * per_th;
1099         }
1100         p = calloc(1, alloc_size);
1101         if (!p) {
1102                 unmap_library(&temp_dso);
1103                 return 0;
1104         }
1105         memcpy(p, &temp_dso, sizeof temp_dso);
1106         p->dev = st.st_dev;
1107         p->ino = st.st_ino;
1108         p->needed_by = needed_by;
1109         p->name = p->buf;
1110         strcpy(p->name, pathname);
1111         /* Add a shortname only if name arg was not an explicit pathname. */
1112         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1113         if (p->tls.image) {
1114                 p->tls_id = ++tls_cnt;
1115                 tls_align = MAXP2(tls_align, p->tls.align);
1116 #ifdef TLS_ABOVE_TP
1117                 p->tls.offset = tls_offset + ( (tls_align-1) &
1118                         -(tls_offset + (uintptr_t)p->tls.image) );
1119                 tls_offset += p->tls.size;
1120 #else
1121                 tls_offset += p->tls.size + p->tls.align - 1;
1122                 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1123                         & (p->tls.align-1);
1124                 p->tls.offset = tls_offset;
1125 #endif
1126                 p->new_dtv = (void *)(-sizeof(size_t) &
1127                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1128                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1129                 if (tls_tail) tls_tail->next = &p->tls;
1130                 else libc.tls_head = &p->tls;
1131                 tls_tail = &p->tls;
1132         }
1133
1134         tail->next = p;
1135         p->prev = tail;
1136         tail = p;
1137
1138         if (DL_FDPIC) makefuncdescs(p);
1139
1140         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1141
1142         return p;
1143 }
1144
1145 static void load_direct_deps(struct dso *p)
1146 {
1147         size_t i, cnt;
1148         if (p->deps) return;
1149         for (i=cnt=0; p->dynv[i]; i+=2)
1150                 if (p->dynv[i] == DT_NEEDED) cnt++;
1151         p->deps = calloc(cnt+1, sizeof *p->deps);
1152         if (!p->deps) {
1153                 error("Error loading dependencies for %s", p->name);
1154                 if (runtime) longjmp(*rtld_fail, 1);
1155         }
1156         for (i=cnt=0; p->dynv[i]; i+=2) {
1157                 if (p->dynv[i] != DT_NEEDED) continue;
1158                 struct dso *dep = load_library(p->strings + p->dynv[i+1], p);
1159                 if (!dep) {
1160                         error("Error loading shared library %s: %m (needed by %s)",
1161                                 p->strings + p->dynv[i+1], p->name);
1162                         if (runtime) longjmp(*rtld_fail, 1);
1163                         continue;
1164                 }
1165                 p->deps[cnt++] = dep;
1166                 p->deps[cnt] = 0;
1167         }
1168         p->ndeps_direct = cnt;
1169 }
1170
1171 static void load_deps(struct dso *p)
1172 {
1173         if (p->deps) return;
1174         for (; p; p=p->next)
1175                 load_direct_deps(p);
1176 }
1177
1178 static void extend_bfs_deps(struct dso *p)
1179 {
1180         size_t i, j, cnt, ndeps_all;
1181         struct dso **tmp;
1182
1183         if (p->bfs_built) return;
1184         ndeps_all = p->ndeps_direct;
1185
1186         /* Mark existing (direct) deps so they won't be duplicated. */
1187         for (i=0; p->deps[i]; i++)
1188                 p->deps[i]->mark = 1;
1189
1190         /* For each dependency already in the list, copy its list of direct
1191          * dependencies to the list, excluding any items already in the
1192          * list. Note that the list this loop iterates over will grow during
1193          * the loop, but since duplicates are excluded, growth is bounded. */
1194         for (i=0; p->deps[i]; i++) {
1195                 struct dso *dep = p->deps[i];
1196                 for (j=cnt=0; j<dep->ndeps_direct; j++)
1197                         if (!dep->deps[j]->mark) cnt++;
1198                 tmp = realloc(p->deps, sizeof(*p->deps) * (ndeps_all+cnt+1));
1199                 if (!tmp) {
1200                         error("Error recording dependencies for %s", p->name);
1201                         if (runtime) longjmp(*rtld_fail, 1);
1202                         continue;
1203                 }
1204                 p->deps = tmp;
1205                 for (j=0; j<dep->ndeps_direct; j++) {
1206                         if (dep->deps[j]->mark) continue;
1207                         dep->deps[j]->mark = 1;
1208                         p->deps[ndeps_all++] = dep->deps[j];
1209                 }
1210                 p->deps[ndeps_all] = 0;
1211         }
1212         p->bfs_built = 1;
1213         for (p=head; p; p=p->next)
1214                 p->mark = 0;
1215 }
1216
1217 static void load_preload(char *s)
1218 {
1219         int tmp;
1220         char *z;
1221         for (z=s; *z; s=z) {
1222                 for (   ; *s && (isspace(*s) || *s==':'); s++);
1223                 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1224                 tmp = *z;
1225                 *z = 0;
1226                 load_library(s, 0);
1227                 *z = tmp;
1228         }
1229 }
1230
1231 static void add_syms(struct dso *p)
1232 {
1233         if (!p->syms_next && syms_tail != p) {
1234                 syms_tail->syms_next = p;
1235                 syms_tail = p;
1236         }
1237 }
1238
1239 static void revert_syms(struct dso *old_tail)
1240 {
1241         struct dso *p, *next;
1242         /* Chop off the tail of the list of dsos that participate in
1243          * the global symbol table, reverting them to RTLD_LOCAL. */
1244         for (p=old_tail; p; p=next) {
1245                 next = p->syms_next;
1246                 p->syms_next = 0;
1247         }
1248         syms_tail = old_tail;
1249 }
1250
1251 static void do_mips_relocs(struct dso *p, size_t *got)
1252 {
1253         size_t i, j, rel[2];
1254         unsigned char *base = p->base;
1255         i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1256         if (p==&ldso) {
1257                 got += i;
1258         } else {
1259                 while (i--) *got++ += (size_t)base;
1260         }
1261         j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1262         i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1263         Sym *sym = p->syms + j;
1264         rel[0] = (unsigned char *)got - base;
1265         for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1266                 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1267                 do_relocs(p, rel, sizeof rel, 2);
1268         }
1269 }
1270
1271 static void reloc_all(struct dso *p)
1272 {
1273         size_t dyn[DYN_CNT];
1274         for (; p; p=p->next) {
1275                 if (p->relocated) continue;
1276                 decode_vec(p->dynv, dyn, DYN_CNT);
1277                 if (NEED_MIPS_GOT_RELOCS)
1278                         do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1279                 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1280                         2+(dyn[DT_PLTREL]==DT_RELA));
1281                 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1282                 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1283
1284                 if (head != &ldso && p->relro_start != p->relro_end &&
1285                     mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1286                     && errno != ENOSYS) {
1287                         error("Error relocating %s: RELRO protection failed: %m",
1288                                 p->name);
1289                         if (runtime) longjmp(*rtld_fail, 1);
1290                 }
1291
1292                 p->relocated = 1;
1293         }
1294 }
1295
1296 static void kernel_mapped_dso(struct dso *p)
1297 {
1298         size_t min_addr = -1, max_addr = 0, cnt;
1299         Phdr *ph = p->phdr;
1300         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1301                 if (ph->p_type == PT_DYNAMIC) {
1302                         p->dynv = laddr(p, ph->p_vaddr);
1303                 } else if (ph->p_type == PT_GNU_RELRO) {
1304                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1305                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1306                 } else if (ph->p_type == PT_GNU_STACK) {
1307                         if (!runtime && ph->p_memsz > __default_stacksize) {
1308                                 __default_stacksize =
1309                                         ph->p_memsz < DEFAULT_STACK_MAX ?
1310                                         ph->p_memsz : DEFAULT_STACK_MAX;
1311                         }
1312                 }
1313                 if (ph->p_type != PT_LOAD) continue;
1314                 if (ph->p_vaddr < min_addr)
1315                         min_addr = ph->p_vaddr;
1316                 if (ph->p_vaddr+ph->p_memsz > max_addr)
1317                         max_addr = ph->p_vaddr+ph->p_memsz;
1318         }
1319         min_addr &= -PAGE_SIZE;
1320         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1321         p->map = p->base + min_addr;
1322         p->map_len = max_addr - min_addr;
1323         p->kernel_mapped = 1;
1324 }
1325
1326 void __libc_exit_fini()
1327 {
1328         struct dso *p;
1329         size_t dyn[DYN_CNT];
1330         for (p=fini_head; p; p=p->fini_next) {
1331                 if (!p->constructed) continue;
1332                 decode_vec(p->dynv, dyn, DYN_CNT);
1333                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1334                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1335                         size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1336                         while (n--) ((void (*)(void))*--fn)();
1337                 }
1338 #ifndef NO_LEGACY_INITFINI
1339                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1340                         fpaddr(p, dyn[DT_FINI])();
1341 #endif
1342         }
1343 }
1344
1345 static void do_init_fini(struct dso *p)
1346 {
1347         size_t dyn[DYN_CNT];
1348         int need_locking = libc.threads_minus_1;
1349         /* Allow recursive calls that arise when a library calls
1350          * dlopen from one of its constructors, but block any
1351          * other threads until all ctors have finished. */
1352         if (need_locking) pthread_mutex_lock(&init_fini_lock);
1353         for (; p; p=p->prev) {
1354                 if (p->constructed) continue;
1355                 p->constructed = 1;
1356                 decode_vec(p->dynv, dyn, DYN_CNT);
1357                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1358                         p->fini_next = fini_head;
1359                         fini_head = p;
1360                 }
1361 #ifndef NO_LEGACY_INITFINI
1362                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1363                         fpaddr(p, dyn[DT_INIT])();
1364 #endif
1365                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1366                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1367                         size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1368                         while (n--) ((void (*)(void))*fn++)();
1369                 }
1370                 if (!need_locking && libc.threads_minus_1) {
1371                         need_locking = 1;
1372                         pthread_mutex_lock(&init_fini_lock);
1373                 }
1374         }
1375         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1376 }
1377
1378 void __libc_start_init(void)
1379 {
1380         do_init_fini(tail);
1381 }
1382
1383 static void dl_debug_state(void)
1384 {
1385 }
1386
1387 weak_alias(dl_debug_state, _dl_debug_state);
1388
1389 void __init_tls(size_t *auxv)
1390 {
1391 }
1392
1393 static void update_tls_size()
1394 {
1395         libc.tls_cnt = tls_cnt;
1396         libc.tls_align = tls_align;
1397         libc.tls_size = ALIGN(
1398                 (1+tls_cnt) * sizeof(void *) +
1399                 tls_offset +
1400                 sizeof(struct pthread) +
1401                 tls_align * 2,
1402         tls_align);
1403 }
1404
1405 static void install_new_tls(void)
1406 {
1407         sigset_t set;
1408         pthread_t self = __pthread_self(), td;
1409         struct dso *dtv_provider = container_of(tls_tail, struct dso, tls);
1410         uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv;
1411         struct dso *p;
1412         size_t i, j;
1413         size_t old_cnt = self->dtv[0];
1414
1415         __block_app_sigs(&set);
1416         __tl_lock();
1417         /* Copy existing dtv contents from all existing threads. */
1418         for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1419                 memcpy(newdtv+i, td->dtv,
1420                         (old_cnt+1)*sizeof(uintptr_t));
1421                 newdtv[i][0] = tls_cnt;
1422         }
1423         /* Install new dtls into the enlarged, uninstalled dtv copies. */
1424         for (p=head; ; p=p->next) {
1425                 if (p->tls_id <= old_cnt) continue;
1426                 unsigned char *mem = p->new_tls;
1427                 for (j=0; j<i; j++) {
1428                         unsigned char *new = mem;
1429                         new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1430                                 & (p->tls.align-1);
1431                         memcpy(new, p->tls.image, p->tls.len);
1432                         newdtv[j][p->tls_id] =
1433                                 (uintptr_t)new + DTP_OFFSET;
1434                         mem += p->tls.size + p->tls.align;
1435                 }
1436                 if (p->tls_id == tls_cnt) break;
1437         }
1438
1439         /* Broadcast barrier to ensure contents of new dtv is visible
1440          * if the new dtv pointer is. The __membarrier function has a
1441          * fallback emulation using signals for kernels that lack the
1442          * feature at the syscall level. */
1443
1444         __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1445
1446         /* Install new dtv for each thread. */
1447         for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1448                 td->dtv = td->dtv_copy = newdtv[j];
1449         }
1450
1451         __tl_unlock();
1452         __restore_sigs(&set);
1453 }
1454
1455 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1456  * following stage 2 and stage 3 functions via primitive symbolic lookup
1457  * since it does not have access to their addresses to begin with. */
1458
1459 /* Stage 2 of the dynamic linker is called after relative relocations
1460  * have been processed. It can make function calls to static functions
1461  * and access string literals and static data, but cannot use extern
1462  * symbols. Its job is to perform symbolic relocations on the dynamic
1463  * linker itself, but some of the relocations performed may need to be
1464  * replaced later due to copy relocations in the main program. */
1465
1466 hidden void __dls2(unsigned char *base, size_t *sp)
1467 {
1468         if (DL_FDPIC) {
1469                 void *p1 = (void *)sp[-2];
1470                 void *p2 = (void *)sp[-1];
1471                 if (!p1) {
1472                         size_t *auxv, aux[AUX_CNT];
1473                         for (auxv=sp+1+*sp+1; *auxv; auxv++);
1474                         auxv++;
1475                         decode_vec(auxv, aux, AUX_CNT);
1476                         if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1477                         else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1478                 }
1479                 app_loadmap = p2 ? p1 : 0;
1480                 ldso.loadmap = p2 ? p2 : p1;
1481                 ldso.base = laddr(&ldso, 0);
1482         } else {
1483                 ldso.base = base;
1484         }
1485         Ehdr *ehdr = (void *)ldso.base;
1486         ldso.name = ldso.shortname = "libc.so";
1487         ldso.phnum = ehdr->e_phnum;
1488         ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1489         ldso.phentsize = ehdr->e_phentsize;
1490         kernel_mapped_dso(&ldso);
1491         decode_dyn(&ldso);
1492
1493         if (DL_FDPIC) makefuncdescs(&ldso);
1494
1495         /* Prepare storage for to save clobbered REL addends so they
1496          * can be reused in stage 3. There should be very few. If
1497          * something goes wrong and there are a huge number, abort
1498          * instead of risking stack overflow. */
1499         size_t dyn[DYN_CNT];
1500         decode_vec(ldso.dynv, dyn, DYN_CNT);
1501         size_t *rel = laddr(&ldso, dyn[DT_REL]);
1502         size_t rel_size = dyn[DT_RELSZ];
1503         size_t symbolic_rel_cnt = 0;
1504         apply_addends_to = rel;
1505         for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1506                 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1507         if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1508         size_t addends[symbolic_rel_cnt+1];
1509         saved_addends = addends;
1510
1511         head = &ldso;
1512         reloc_all(&ldso);
1513
1514         ldso.relocated = 0;
1515
1516         /* Call dynamic linker stage-2b, __dls2b, looking it up
1517          * symbolically as a barrier against moving the address
1518          * load across the above relocation processing. */
1519         struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1520         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp);
1521         else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp);
1522 }
1523
1524 /* Stage 2b sets up a valid thread pointer, which requires relocations
1525  * completed in stage 2, and on which stage 3 is permitted to depend.
1526  * This is done as a separate stage, with symbolic lookup as a barrier,
1527  * so that loads of the thread pointer and &errno can be pure/const and
1528  * thereby hoistable. */
1529
1530 _Noreturn void __dls2b(size_t *sp)
1531 {
1532         /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1533          * use during dynamic linking. If possible it will also serve as the
1534          * thread pointer at runtime. */
1535         libc.tls_size = sizeof builtin_tls;
1536         libc.tls_align = tls_align;
1537         if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1538                 a_crash();
1539         }
1540
1541         struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1542         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1543         else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1544 }
1545
1546 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1547  * fully functional. Its job is to load (if not already loaded) and
1548  * process dependencies and relocations for the main application and
1549  * transfer control to its entry point. */
1550
1551 _Noreturn void __dls3(size_t *sp)
1552 {
1553         static struct dso app, vdso;
1554         size_t aux[AUX_CNT], *auxv;
1555         size_t i;
1556         char *env_preload=0;
1557         char *replace_argv0=0;
1558         size_t vdso_base;
1559         int argc = *sp;
1560         char **argv = (void *)(sp+1);
1561         char **argv_orig = argv;
1562         char **envp = argv+argc+1;
1563
1564         /* Find aux vector just past environ[] and use it to initialize
1565          * global data that may be needed before we can make syscalls. */
1566         __environ = envp;
1567         for (i=argc+1; argv[i]; i++);
1568         libc.auxv = auxv = (void *)(argv+i+1);
1569         decode_vec(auxv, aux, AUX_CNT);
1570         __hwcap = aux[AT_HWCAP];
1571         libc.page_size = aux[AT_PAGESZ];
1572         libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1573                 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1574
1575         /* Only trust user/env if kernel says we're not suid/sgid */
1576         if (!libc.secure) {
1577                 env_path = getenv("LD_LIBRARY_PATH");
1578                 env_preload = getenv("LD_PRELOAD");
1579         }
1580
1581         /* If the main program was already loaded by the kernel,
1582          * AT_PHDR will point to some location other than the dynamic
1583          * linker's program headers. */
1584         if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1585                 size_t interp_off = 0;
1586                 size_t tls_image = 0;
1587                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1588                 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1589                 app.phnum = aux[AT_PHNUM];
1590                 app.phentsize = aux[AT_PHENT];
1591                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1592                         if (phdr->p_type == PT_PHDR)
1593                                 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1594                         else if (phdr->p_type == PT_INTERP)
1595                                 interp_off = (size_t)phdr->p_vaddr;
1596                         else if (phdr->p_type == PT_TLS) {
1597                                 tls_image = phdr->p_vaddr;
1598                                 app.tls.len = phdr->p_filesz;
1599                                 app.tls.size = phdr->p_memsz;
1600                                 app.tls.align = phdr->p_align;
1601                         }
1602                 }
1603                 if (DL_FDPIC) app.loadmap = app_loadmap;
1604                 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1605                 if (interp_off) ldso.name = laddr(&app, interp_off);
1606                 if ((aux[0] & (1UL<<AT_EXECFN))
1607                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1608                         app.name = (char *)aux[AT_EXECFN];
1609                 else
1610                         app.name = argv[0];
1611                 kernel_mapped_dso(&app);
1612         } else {
1613                 int fd;
1614                 char *ldname = argv[0];
1615                 size_t l = strlen(ldname);
1616                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1617                 argv++;
1618                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1619                         char *opt = argv[0]+2;
1620                         *argv++ = (void *)-1;
1621                         if (!*opt) {
1622                                 break;
1623                         } else if (!memcmp(opt, "list", 5)) {
1624                                 ldd_mode = 1;
1625                         } else if (!memcmp(opt, "library-path", 12)) {
1626                                 if (opt[12]=='=') env_path = opt+13;
1627                                 else if (opt[12]) *argv = 0;
1628                                 else if (*argv) env_path = *argv++;
1629                         } else if (!memcmp(opt, "preload", 7)) {
1630                                 if (opt[7]=='=') env_preload = opt+8;
1631                                 else if (opt[7]) *argv = 0;
1632                                 else if (*argv) env_preload = *argv++;
1633                         } else if (!memcmp(opt, "argv0", 5)) {
1634                                 if (opt[5]=='=') replace_argv0 = opt+6;
1635                                 else if (opt[5]) *argv = 0;
1636                                 else if (*argv) replace_argv0 = *argv++;
1637                         } else {
1638                                 argv[0] = 0;
1639                         }
1640                 }
1641                 argv[-1] = (void *)(argc - (argv-argv_orig));
1642                 if (!argv[0]) {
1643                         dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1644                                 "Version %s\n"
1645                                 "Dynamic Program Loader\n"
1646                                 "Usage: %s [options] [--] pathname%s\n",
1647                                 __libc_version, ldname,
1648                                 ldd_mode ? "" : " [args]");
1649                         _exit(1);
1650                 }
1651                 fd = open(argv[0], O_RDONLY);
1652                 if (fd < 0) {
1653                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1654                         _exit(1);
1655                 }
1656                 Ehdr *ehdr = (void *)map_library(fd, &app);
1657                 if (!ehdr) {
1658                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1659                         _exit(1);
1660                 }
1661                 close(fd);
1662                 ldso.name = ldname;
1663                 app.name = argv[0];
1664                 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1665                 /* Find the name that would have been used for the dynamic
1666                  * linker had ldd not taken its place. */
1667                 if (ldd_mode) {
1668                         for (i=0; i<app.phnum; i++) {
1669                                 if (app.phdr[i].p_type == PT_INTERP)
1670                                         ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1671                         }
1672                         dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1673                 }
1674         }
1675         if (app.tls.size) {
1676                 libc.tls_head = tls_tail = &app.tls;
1677                 app.tls_id = tls_cnt = 1;
1678 #ifdef TLS_ABOVE_TP
1679                 app.tls.offset = GAP_ABOVE_TP;
1680                 app.tls.offset += -GAP_ABOVE_TP & (app.tls.align-1);
1681                 tls_offset = app.tls.offset + app.tls.size
1682                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1683                         & (app.tls.align-1) );
1684 #else
1685                 tls_offset = app.tls.offset = app.tls.size
1686                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1687                         & (app.tls.align-1) );
1688 #endif
1689                 tls_align = MAXP2(tls_align, app.tls.align);
1690         }
1691         decode_dyn(&app);
1692         if (DL_FDPIC) {
1693                 makefuncdescs(&app);
1694                 if (!app.loadmap) {
1695                         app.loadmap = (void *)&app_dummy_loadmap;
1696                         app.loadmap->nsegs = 1;
1697                         app.loadmap->segs[0].addr = (size_t)app.map;
1698                         app.loadmap->segs[0].p_vaddr = (size_t)app.map
1699                                 - (size_t)app.base;
1700                         app.loadmap->segs[0].p_memsz = app.map_len;
1701                 }
1702                 argv[-3] = (void *)app.loadmap;
1703         }
1704
1705         /* Initial dso chain consists only of the app. */
1706         head = tail = syms_tail = &app;
1707
1708         /* Donate unused parts of app and library mapping to malloc */
1709         reclaim_gaps(&app);
1710         reclaim_gaps(&ldso);
1711
1712         /* Load preload/needed libraries, add symbols to global namespace. */
1713         if (env_preload) load_preload(env_preload);
1714         load_deps(&app);
1715         for (struct dso *p=head; p; p=p->next)
1716                 add_syms(p);
1717
1718         /* Attach to vdso, if provided by the kernel, last so that it does
1719          * not become part of the global namespace.  */
1720         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1721                 Ehdr *ehdr = (void *)vdso_base;
1722                 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1723                 vdso.phnum = ehdr->e_phnum;
1724                 vdso.phentsize = ehdr->e_phentsize;
1725                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1726                         if (phdr->p_type == PT_DYNAMIC)
1727                                 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1728                         if (phdr->p_type == PT_LOAD)
1729                                 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1730                 }
1731                 vdso.name = "";
1732                 vdso.shortname = "linux-gate.so.1";
1733                 vdso.relocated = 1;
1734                 decode_dyn(&vdso);
1735                 vdso.prev = tail;
1736                 tail->next = &vdso;
1737                 tail = &vdso;
1738         }
1739
1740         for (i=0; app.dynv[i]; i+=2) {
1741                 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1742                         app.dynv[i+1] = (size_t)&debug;
1743                 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1744                         size_t *ptr = (size_t *) app.dynv[i+1];
1745                         *ptr = (size_t)&debug;
1746                 }
1747         }
1748
1749         /* The main program must be relocated LAST since it may contin
1750          * copy relocations which depend on libraries' relocations. */
1751         reloc_all(app.next);
1752         reloc_all(&app);
1753
1754         update_tls_size();
1755         if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1756                 void *initial_tls = calloc(libc.tls_size, 1);
1757                 if (!initial_tls) {
1758                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1759                                 argv[0], libc.tls_size);
1760                         _exit(127);
1761                 }
1762                 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1763                         a_crash();
1764                 }
1765         } else {
1766                 size_t tmp_tls_size = libc.tls_size;
1767                 pthread_t self = __pthread_self();
1768                 /* Temporarily set the tls size to the full size of
1769                  * builtin_tls so that __copy_tls will use the same layout
1770                  * as it did for before. Then check, just to be safe. */
1771                 libc.tls_size = sizeof builtin_tls;
1772                 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1773                 libc.tls_size = tmp_tls_size;
1774         }
1775         static_tls_cnt = tls_cnt;
1776
1777         if (ldso_fail) _exit(127);
1778         if (ldd_mode) _exit(0);
1779
1780         /* Determine if malloc was interposed by a replacement implementation
1781          * so that calloc and the memalign family can harden against the
1782          * possibility of incomplete replacement. */
1783         if (find_sym(head, "malloc", 1).dso != &ldso)
1784                 __malloc_replaced = 1;
1785
1786         /* Switch to runtime mode: any further failures in the dynamic
1787          * linker are a reportable failure rather than a fatal startup
1788          * error. */
1789         runtime = 1;
1790
1791         debug.ver = 1;
1792         debug.bp = dl_debug_state;
1793         debug.head = head;
1794         debug.base = ldso.base;
1795         debug.state = 0;
1796         _dl_debug_state();
1797
1798         if (replace_argv0) argv[0] = replace_argv0;
1799
1800         errno = 0;
1801
1802         CRTJMP((void *)aux[AT_ENTRY], argv-1);
1803         for(;;);
1804 }
1805
1806 static void prepare_lazy(struct dso *p)
1807 {
1808         size_t dyn[DYN_CNT], n, flags1=0;
1809         decode_vec(p->dynv, dyn, DYN_CNT);
1810         search_vec(p->dynv, &flags1, DT_FLAGS_1);
1811         if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1812                 return;
1813         n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1814         if (NEED_MIPS_GOT_RELOCS) {
1815                 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1816                 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1817                 n += i-j;
1818         }
1819         p->lazy = calloc(n, 3*sizeof(size_t));
1820         if (!p->lazy) {
1821                 error("Error preparing lazy relocation for %s: %m", p->name);
1822                 longjmp(*rtld_fail, 1);
1823         }
1824         p->lazy_next = lazy_head;
1825         lazy_head = p;
1826 }
1827
1828 void *dlopen(const char *file, int mode)
1829 {
1830         struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1831         struct tls_module *orig_tls_tail;
1832         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1833         size_t i;
1834         int cs;
1835         jmp_buf jb;
1836
1837         if (!file) return head;
1838
1839         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1840         pthread_rwlock_wrlock(&lock);
1841         __inhibit_ptc();
1842
1843         p = 0;
1844         orig_tls_tail = tls_tail;
1845         orig_tls_cnt = tls_cnt;
1846         orig_tls_offset = tls_offset;
1847         orig_tls_align = tls_align;
1848         orig_lazy_head = lazy_head;
1849         orig_syms_tail = syms_tail;
1850         orig_tail = tail;
1851         noload = mode & RTLD_NOLOAD;
1852
1853         rtld_fail = &jb;
1854         if (setjmp(*rtld_fail)) {
1855                 /* Clean up anything new that was (partially) loaded */
1856                 revert_syms(orig_syms_tail);
1857                 for (p=orig_tail->next; p; p=next) {
1858                         next = p->next;
1859                         while (p->td_index) {
1860                                 void *tmp = p->td_index->next;
1861                                 free(p->td_index);
1862                                 p->td_index = tmp;
1863                         }
1864                         free(p->funcdescs);
1865                         if (p->rpath != p->rpath_orig)
1866                                 free(p->rpath);
1867                         free(p->deps);
1868                         unmap_library(p);
1869                         free(p);
1870                 }
1871                 if (!orig_tls_tail) libc.tls_head = 0;
1872                 tls_tail = orig_tls_tail;
1873                 if (tls_tail) tls_tail->next = 0;
1874                 tls_cnt = orig_tls_cnt;
1875                 tls_offset = orig_tls_offset;
1876                 tls_align = orig_tls_align;
1877                 lazy_head = orig_lazy_head;
1878                 tail = orig_tail;
1879                 tail->next = 0;
1880                 p = 0;
1881                 goto end;
1882         } else p = load_library(file, head);
1883
1884         if (!p) {
1885                 error(noload ?
1886                         "Library %s is not already loaded" :
1887                         "Error loading shared library %s: %m",
1888                         file);
1889                 goto end;
1890         }
1891
1892         /* First load handling */
1893         load_deps(p);
1894         extend_bfs_deps(p);
1895         if (!p->relocated && (mode & RTLD_LAZY)) {
1896                 prepare_lazy(p);
1897                 for (i=0; p->deps[i]; i++)
1898                         if (!p->deps[i]->relocated)
1899                                 prepare_lazy(p->deps[i]);
1900         }
1901         if (!p->relocated || (mode & RTLD_GLOBAL)) {
1902                 /* Make new symbols global, at least temporarily, so we can do
1903                  * relocations. If not RTLD_GLOBAL, this is reverted below. */
1904                 add_syms(p);
1905                 for (i=0; p->deps[i]; i++)
1906                         add_syms(p->deps[i]);
1907         }
1908         if (!p->relocated) {
1909                 reloc_all(p);
1910         }
1911
1912         /* If RTLD_GLOBAL was not specified, undo any new additions
1913          * to the global symbol table. This is a nop if the library was
1914          * previously loaded and already global. */
1915         if (!(mode & RTLD_GLOBAL))
1916                 revert_syms(orig_syms_tail);
1917
1918         /* Processing of deferred lazy relocations must not happen until
1919          * the new libraries are committed; otherwise we could end up with
1920          * relocations resolved to symbol definitions that get removed. */
1921         redo_lazy_relocs();
1922
1923         update_tls_size();
1924         if (tls_cnt != orig_tls_cnt)
1925                 install_new_tls();
1926         _dl_debug_state();
1927         orig_tail = tail;
1928 end:
1929         __release_ptc();
1930         if (p) gencnt++;
1931         pthread_rwlock_unlock(&lock);
1932         if (p) do_init_fini(orig_tail);
1933         pthread_setcancelstate(cs, 0);
1934         return p;
1935 }
1936
1937 hidden int __dl_invalid_handle(void *h)
1938 {
1939         struct dso *p;
1940         for (p=head; p; p=p->next) if (h==p) return 0;
1941         error("Invalid library handle %p", (void *)h);
1942         return 1;
1943 }
1944
1945 static void *addr2dso(size_t a)
1946 {
1947         struct dso *p;
1948         size_t i;
1949         if (DL_FDPIC) for (p=head; p; p=p->next) {
1950                 i = count_syms(p);
1951                 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1952                         return p;
1953         }
1954         for (p=head; p; p=p->next) {
1955                 if (DL_FDPIC && p->loadmap) {
1956                         for (i=0; i<p->loadmap->nsegs; i++) {
1957                                 if (a-p->loadmap->segs[i].p_vaddr
1958                                     < p->loadmap->segs[i].p_memsz)
1959                                         return p;
1960                         }
1961                 } else {
1962                         Phdr *ph = p->phdr;
1963                         size_t phcnt = p->phnum;
1964                         size_t entsz = p->phentsize;
1965                         size_t base = (size_t)p->base;
1966                         for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
1967                                 if (ph->p_type != PT_LOAD) continue;
1968                                 if (a-base-ph->p_vaddr < ph->p_memsz)
1969                                         return p;
1970                         }
1971                         if (a-(size_t)p->map < p->map_len)
1972                                 return 0;
1973                 }
1974         }
1975         return 0;
1976 }
1977
1978 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1979 {
1980         size_t i;
1981         uint32_t h = 0, gh = 0, *ght;
1982         Sym *sym;
1983         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1984                 if (p == RTLD_DEFAULT) {
1985                         p = head;
1986                 } else if (p == RTLD_NEXT) {
1987                         p = addr2dso((size_t)ra);
1988                         if (!p) p=head;
1989                         p = p->next;
1990                 }
1991                 struct symdef def = find_sym(p, s, 0);
1992                 if (!def.sym) goto failed;
1993                 if ((def.sym->st_info&0xf) == STT_TLS)
1994                         return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
1995                 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1996                         return def.dso->funcdescs + (def.sym - def.dso->syms);
1997                 return laddr(def.dso, def.sym->st_value);
1998         }
1999         if (__dl_invalid_handle(p))
2000                 return 0;
2001         if ((ght = p->ghashtab)) {
2002                 gh = gnu_hash(s);
2003                 sym = gnu_lookup(gh, ght, p, s);
2004         } else {
2005                 h = sysv_hash(s);
2006                 sym = sysv_lookup(s, h, p);
2007         }
2008         if (sym && (sym->st_info&0xf) == STT_TLS)
2009                 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value-DTP_OFFSET});
2010         if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
2011                 return p->funcdescs + (sym - p->syms);
2012         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
2013                 return laddr(p, sym->st_value);
2014         for (i=0; p->deps[i]; i++) {
2015                 if ((ght = p->deps[i]->ghashtab)) {
2016                         if (!gh) gh = gnu_hash(s);
2017                         sym = gnu_lookup(gh, ght, p->deps[i], s);
2018                 } else {
2019                         if (!h) h = sysv_hash(s);
2020                         sym = sysv_lookup(s, h, p->deps[i]);
2021                 }
2022                 if (sym && (sym->st_info&0xf) == STT_TLS)
2023                         return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value-DTP_OFFSET});
2024                 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
2025                         return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
2026                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
2027                         return laddr(p->deps[i], sym->st_value);
2028         }
2029 failed:
2030         error("Symbol not found: %s", s);
2031         return 0;
2032 }
2033
2034 int dladdr(const void *addr_arg, Dl_info *info)
2035 {
2036         size_t addr = (size_t)addr_arg;
2037         struct dso *p;
2038         Sym *sym, *bestsym;
2039         uint32_t nsym;
2040         char *strings;
2041         size_t best = 0;
2042         size_t besterr = -1;
2043
2044         pthread_rwlock_rdlock(&lock);
2045         p = addr2dso(addr);
2046         pthread_rwlock_unlock(&lock);
2047
2048         if (!p) return 0;
2049
2050         sym = p->syms;
2051         strings = p->strings;
2052         nsym = count_syms(p);
2053
2054         if (DL_FDPIC) {
2055                 size_t idx = (addr-(size_t)p->funcdescs)
2056                         / sizeof(*p->funcdescs);
2057                 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2058                         best = (size_t)(p->funcdescs + idx);
2059                         bestsym = sym + idx;
2060                         besterr = 0;
2061                 }
2062         }
2063
2064         if (!best) for (; nsym; nsym--, sym++) {
2065                 if (sym->st_value
2066                  && (1<<(sym->st_info&0xf) & OK_TYPES)
2067                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
2068                         size_t symaddr = (size_t)laddr(p, sym->st_value);
2069                         if (symaddr > addr || symaddr <= best)
2070                                 continue;
2071                         best = symaddr;
2072                         bestsym = sym;
2073                         besterr = addr - symaddr;
2074                         if (addr == symaddr)
2075                                 break;
2076                 }
2077         }
2078
2079         if (bestsym && besterr > bestsym->st_size-1) {
2080                 best = 0;
2081                 bestsym = 0;
2082         }
2083
2084         info->dli_fname = p->name;
2085         info->dli_fbase = p->map;
2086
2087         if (!best) {
2088                 info->dli_sname = 0;
2089                 info->dli_saddr = 0;
2090                 return 1;
2091         }
2092
2093         if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2094                 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2095         info->dli_sname = strings + bestsym->st_name;
2096         info->dli_saddr = (void *)best;
2097
2098         return 1;
2099 }
2100
2101 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2102 {
2103         void *res;
2104         pthread_rwlock_rdlock(&lock);
2105         res = do_dlsym(p, s, ra);
2106         pthread_rwlock_unlock(&lock);
2107         return res;
2108 }
2109
2110 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2111 {
2112         struct dso *current;
2113         struct dl_phdr_info info;
2114         int ret = 0;
2115         for(current = head; current;) {
2116                 info.dlpi_addr      = (uintptr_t)current->base;
2117                 info.dlpi_name      = current->name;
2118                 info.dlpi_phdr      = current->phdr;
2119                 info.dlpi_phnum     = current->phnum;
2120                 info.dlpi_adds      = gencnt;
2121                 info.dlpi_subs      = 0;
2122                 info.dlpi_tls_modid = current->tls_id;
2123                 info.dlpi_tls_data  = current->tls.image;
2124
2125                 ret = (callback)(&info, sizeof (info), data);
2126
2127                 if (ret != 0) break;
2128
2129                 pthread_rwlock_rdlock(&lock);
2130                 current = current->next;
2131                 pthread_rwlock_unlock(&lock);
2132         }
2133         return ret;
2134 }
2135
2136 static void error(const char *fmt, ...)
2137 {
2138         va_list ap;
2139         va_start(ap, fmt);
2140         if (!runtime) {
2141                 vdprintf(2, fmt, ap);
2142                 dprintf(2, "\n");
2143                 ldso_fail = 1;
2144                 va_end(ap);
2145                 return;
2146         }
2147         __dl_vseterr(fmt, ap);
2148         va_end(ap);
2149 }