nsz Git - musl/blob - ldso/dynlink.c

   1 #define _GNU_SOURCE
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <stdarg.h>
   5 #include <stddef.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <stdint.h>
   9 #include <elf.h>
  10 #include <sys/mman.h>
  11 #include <limits.h>
  12 #include <fcntl.h>
  13 #include <sys/stat.h>
  14 #include <errno.h>
  15 #include <link.h>
  16 #include <setjmp.h>
  17 #include <pthread.h>
  18 #include <ctype.h>
  19 #include <dlfcn.h>
  20 #include <semaphore.h>
  21 #include <sys/membarrier.h>
  22 #include "pthread_impl.h"
  23 #include "libc.h"
  24 #include "dynlink.h"
  25 #include "malloc_impl.h"
  26
  27 static void error(const char *, ...);
  28
  29 #define MAXP2(a,b) (-(-(a)&-(b)))
  30 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  31
  32 #define container_of(p,t,m) ((t*)((char *)(p)-offsetof(t,m)))
  33
  34 struct debug {
  35         int ver;
  36         void *head;
  37         void (*bp)(void);
  38         int state;
  39         void *base;
  40 };
  41
  42 struct td_index {
  43         size_t args[2];
  44         struct td_index *next;
  45 };
  46
  47 struct dso {
  48 #if DL_FDPIC
  49         struct fdpic_loadmap *loadmap;
  50 #else
  51         unsigned char *base;
  52 #endif
  53         char *name;
  54         size_t *dynv;
  55         struct dso *next, *prev;
  56
  57         Phdr *phdr;
  58         int phnum;
  59         size_t phentsize;
  60         Sym *syms;
  61         Elf_Symndx *hashtab;
  62         uint32_t *ghashtab;
  63         int16_t *versym;
  64         char *strings;
  65         struct dso *syms_next, *lazy_next;
  66         size_t *lazy, lazy_cnt;
  67         unsigned char *map;
  68         size_t map_len;
  69         dev_t dev;
  70         ino_t ino;
  71         char relocated;
  72         char constructed;
  73         char kernel_mapped;
  74         char mark;
  75         char bfs_built;
  76         char runtime_loaded;
  77         struct dso **deps, *needed_by;
  78         size_t ndeps_direct;
  79         char *rpath_orig, *rpath;
  80         struct tls_module tls;
  81         size_t tls_id;
  82         size_t relro_start, relro_end;
  83         uintptr_t *new_dtv;
  84         unsigned char *new_tls;
  85         volatile int new_dtv_idx, new_tls_idx;
  86         struct td_index *td_index;
  87         struct dso *fini_next;
  88         char *shortname;
  89 #if DL_FDPIC
  90         unsigned char *base;
  91 #else
  92         struct fdpic_loadmap *loadmap;
  93 #endif
  94         struct funcdesc {
  95                 void *addr;
  96                 size_t *got;
  97         } *funcdescs;
  98         size_t *got;
  99         char buf[];
 100 };
 101
 102 struct symdef {
 103         Sym *sym;
 104         struct dso *dso;
 105 };
 106
 107 static struct builtin_tls {
 108         char c;
 109         struct pthread pt;
 110         void *space[16];
 111 } builtin_tls[1];
 112 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
 113
 114 #define ADDEND_LIMIT 4096
 115 static size_t *saved_addends, *apply_addends_to;
 116
 117 static struct dso ldso;
 118 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
 119 static char *env_path, *sys_path;
 120 static unsigned long long gencnt;
 121 static int runtime;
 122 static int ldd_mode;
 123 static int ldso_fail;
 124 static int noload;
 125 static jmp_buf *rtld_fail;
 126 static pthread_rwlock_t lock;
 127 static struct debug debug;
 128 static struct tls_module *tls_tail;
 129 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
 130 static size_t static_tls_cnt;
 131 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 132 static struct fdpic_loadmap *app_loadmap;
 133 static struct fdpic_dummy_loadmap app_dummy_loadmap;
 134
 135 struct debug *_dl_debug_addr = &debug;
 136
 137 extern hidden int __malloc_replaced;
 138
 139 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
 140
 141 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
 142
 143 weak_alias(__init_array_start, __init_array_end);
 144 weak_alias(__fini_array_start, __fini_array_end);
 145
 146 static int dl_strcmp(const char *l, const char *r)
 147 {
 148         for (; *l==*r && *l; l++, r++);
 149         return *(unsigned char *)l - *(unsigned char *)r;
 150 }
 151 #define strcmp(l,r) dl_strcmp(l,r)
 152
 153 /* Compute load address for a virtual address in a given dso. */
 154 #if DL_FDPIC
 155 static void *laddr(const struct dso *p, size_t v)
 156 {
 157         size_t j=0;
 158         if (!p->loadmap) return p->base + v;
 159         for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
 160         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 161 }
 162 static void *laddr_pg(const struct dso *p, size_t v)
 163 {
 164         size_t j=0;
 165         size_t pgsz = PAGE_SIZE;
 166         if (!p->loadmap) return p->base + v;
 167         for (j=0; ; j++) {
 168                 size_t a = p->loadmap->segs[j].p_vaddr;
 169                 size_t b = a + p->loadmap->segs[j].p_memsz;
 170                 a &= -pgsz;
 171                 b += pgsz-1;
 172                 b &= -pgsz;
 173                 if (v-a<b-a) break;
 174         }
 175         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 176 }
 177 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
 178         laddr(p, v), (p)->got })
 179 #else
 180 #define laddr(p, v) (void *)((p)->base + (v))
 181 #define laddr_pg(p, v) laddr(p, v)
 182 #define fpaddr(p, v) ((void (*)())laddr(p, v))
 183 #endif
 184
 185 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 186 {
 187         size_t i;
 188         for (i=0; i<cnt; i++) a[i] = 0;
 189         for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
 190                 a[0] |= 1UL<<v[0];
 191                 a[v[0]] = v[1];
 192         }
 193 }
 194
 195 static int search_vec(size_t *v, size_t *r, size_t key)
 196 {
 197         for (; v[0]!=key; v+=2)
 198                 if (!v[0]) return 0;
 199         *r = v[1];
 200         return 1;
 201 }
 202
 203 static uint32_t sysv_hash(const char *s0)
 204 {
 205         const unsigned char *s = (void *)s0;
 206         uint_fast32_t h = 0;
 207         while (*s) {
 208                 h = 16*h + *s++;
 209                 h ^= h>>24 & 0xf0;
 210         }
 211         return h & 0xfffffff;
 212 }
 213
 214 static uint32_t gnu_hash(const char *s0)
 215 {
 216         const unsigned char *s = (void *)s0;
 217         uint_fast32_t h = 5381;
 218         for (; *s; s++)
 219                 h += h*32 + *s;
 220         return h;
 221 }
 222
 223 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 224 {
 225         size_t i;
 226         Sym *syms = dso->syms;
 227         Elf_Symndx *hashtab = dso->hashtab;
 228         char *strings = dso->strings;
 229         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 230                 if ((!dso->versym || dso->versym[i] >= 0)
 231                     && (!strcmp(s, strings+syms[i].st_name)))
 232                         return syms+i;
 233         }
 234         return 0;
 235 }
 236
 237 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
 238 {
 239         uint32_t nbuckets = hashtab[0];
 240         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 241         uint32_t i = buckets[h1 % nbuckets];
 242
 243         if (!i) return 0;
 244
 245         uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
 246
 247         for (h1 |= 1; ; i++) {
 248                 uint32_t h2 = *hashval++;
 249                 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
 250                     && !strcmp(s, dso->strings + dso->syms[i].st_name))
 251                         return dso->syms+i;
 252                 if (h2 & 1) break;
 253         }
 254
 255         return 0;
 256 }
 257
 258 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
 259 {
 260         const size_t *bloomwords = (const void *)(hashtab+4);
 261         size_t f = bloomwords[fofs & (hashtab[2]-1)];
 262         if (!(f & fmask)) return 0;
 263
 264         f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
 265         if (!(f & 1)) return 0;
 266
 267         return gnu_lookup(h1, hashtab, dso, s);
 268 }
 269
 270 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 271 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 272
 273 #ifndef ARCH_SYM_REJECT_UND
 274 #define ARCH_SYM_REJECT_UND(s) 0
 275 #endif
 276
 277 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 278 {
 279         uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
 280         size_t ghm = 1ul << gh % (8*sizeof(size_t));
 281         struct symdef def = {0};
 282         for (; dso; dso=dso->syms_next) {
 283                 Sym *sym;
 284                 if ((ght = dso->ghashtab)) {
 285                         sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
 286                 } else {
 287                         if (!h) h = sysv_hash(s);
 288                         sym = sysv_lookup(s, h, dso);
 289                 }
 290                 if (!sym) continue;
 291                 if (!sym->st_shndx)
 292                         if (need_def || (sym->st_info&0xf) == STT_TLS
 293                             || ARCH_SYM_REJECT_UND(sym))
 294                                 continue;
 295                 if (!sym->st_value)
 296                         if ((sym->st_info&0xf) != STT_TLS)
 297                                 continue;
 298                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 299                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 300                 def.sym = sym;
 301                 def.dso = dso;
 302                 break;
 303         }
 304         return def;
 305 }
 306
 307 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 308 {
 309         unsigned char *base = dso->base;
 310         Sym *syms = dso->syms;
 311         char *strings = dso->strings;
 312         Sym *sym;
 313         const char *name;
 314         void *ctx;
 315         int type;
 316         int sym_index;
 317         struct symdef def;
 318         size_t *reloc_addr;
 319         size_t sym_val;
 320         size_t tls_val;
 321         size_t addend;
 322         int skip_relative = 0, reuse_addends = 0, save_slot = 0;
 323
 324         if (dso == &ldso) {
 325                 /* Only ldso's REL table needs addend saving/reuse. */
 326                 if (rel == apply_addends_to)
 327                         reuse_addends = 1;
 328                 skip_relative = 1;
 329         }
 330
 331         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 332                 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
 333                 type = R_TYPE(rel[1]);
 334                 if (type == REL_NONE) continue;
 335                 reloc_addr = laddr(dso, rel[0]);
 336
 337                 if (stride > 2) {
 338                         addend = rel[2];
 339                 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
 340                         addend = 0;
 341                 } else if (reuse_addends) {
 342                         /* Save original addend in stage 2 where the dso
 343                          * chain consists of just ldso; otherwise read back
 344                          * saved addend since the inline one was clobbered. */
 345                         if (head==&ldso)
 346                                 saved_addends[save_slot] = *reloc_addr;
 347                         addend = saved_addends[save_slot++];
 348                 } else {
 349                         addend = *reloc_addr;
 350                 }
 351
 352                 sym_index = R_SYM(rel[1]);
 353                 if (sym_index) {
 354                         sym = syms + sym_index;
 355                         name = strings + sym->st_name;
 356                         ctx = type==REL_COPY ? head->syms_next : head;
 357                         def = (sym->st_info&0xf) == STT_SECTION
 358                                 ? (struct symdef){ .dso = dso, .sym = sym }
 359                                 : find_sym(ctx, name, type==REL_PLT);
 360                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 361                             || sym->st_info>>4 != STB_WEAK)) {
 362                                 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
 363                                         dso->lazy[3*dso->lazy_cnt+0] = rel[0];
 364                                         dso->lazy[3*dso->lazy_cnt+1] = rel[1];
 365                                         dso->lazy[3*dso->lazy_cnt+2] = addend;
 366                                         dso->lazy_cnt++;
 367                                         continue;
 368                                 }
 369                                 error("Error relocating %s: %s: symbol not found",
 370                                         dso->name, name);
 371                                 if (runtime) longjmp(*rtld_fail, 1);
 372                                 continue;
 373                         }
 374                 } else {
 375                         sym = 0;
 376                         def.sym = 0;
 377                         def.dso = dso;
 378                 }
 379
 380                 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
 381                 tls_val = def.sym ? def.sym->st_value : 0;
 382
 383                 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
 384                     && runtime && def.dso->tls_id > static_tls_cnt) {
 385                         error("Error relocating %s: %s: initial-exec TLS "
 386                                 "resolves to dynamic definition in %s",
 387                                 dso->name, name, def.dso->name);
 388                         longjmp(*rtld_fail, 1);
 389                 }
 390
 391                 switch(type) {
 392                 case REL_NONE:
 393                         break;
 394                 case REL_OFFSET:
 395                         addend -= (size_t)reloc_addr;
 396                 case REL_SYMBOLIC:
 397                 case REL_GOT:
 398                 case REL_PLT:
 399                         *reloc_addr = sym_val + addend;
 400                         break;
 401                 case REL_RELATIVE:
 402                         *reloc_addr = (size_t)base + addend;
 403                         break;
 404                 case REL_SYM_OR_REL:
 405                         if (sym) *reloc_addr = sym_val + addend;
 406                         else *reloc_addr = (size_t)base + addend;
 407                         break;
 408                 case REL_COPY:
 409                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 410                         break;
 411                 case REL_OFFSET32:
 412                         *(uint32_t *)reloc_addr = sym_val + addend
 413                                 - (size_t)reloc_addr;
 414                         break;
 415                 case REL_FUNCDESC:
 416                         *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
 417                                 + (def.sym - def.dso->syms)) : 0;
 418                         break;
 419                 case REL_FUNCDESC_VAL:
 420                         if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
 421                         else *reloc_addr = sym_val;
 422                         reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
 423                         break;
 424                 case REL_DTPMOD:
 425                         *reloc_addr = def.dso->tls_id;
 426                         break;
 427                 case REL_DTPOFF:
 428                         *reloc_addr = tls_val + addend - DTP_OFFSET;
 429                         break;
 430 #ifdef TLS_ABOVE_TP
 431                 case REL_TPOFF:
 432                         *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
 433                         break;
 434 #else
 435                 case REL_TPOFF:
 436                         *reloc_addr = tls_val - def.dso->tls.offset + addend;
 437                         break;
 438                 case REL_TPOFF_NEG:
 439                         *reloc_addr = def.dso->tls.offset - tls_val + addend;
 440                         break;
 441 #endif
 442                 case REL_TLSDESC:
 443                         if (stride<3) addend = reloc_addr[1];
 444                         if (runtime && def.dso->tls_id > static_tls_cnt) {
 445                                 struct td_index *new = malloc(sizeof *new);
 446                                 if (!new) {
 447                                         error(
 448                                         "Error relocating %s: cannot allocate TLSDESC for %s",
 449                                         dso->name, sym ? name : "(local)" );
 450                                         longjmp(*rtld_fail, 1);
 451                                 }
 452                                 new->next = dso->td_index;
 453                                 dso->td_index = new;
 454                                 new->args[0] = def.dso->tls_id;
 455                                 new->args[1] = tls_val + addend - DTP_OFFSET;
 456                                 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
 457                                 reloc_addr[1] = (size_t)new;
 458                         } else {
 459                                 reloc_addr[0] = (size_t)__tlsdesc_static;
 460 #ifdef TLS_ABOVE_TP
 461                                 reloc_addr[1] = tls_val + def.dso->tls.offset
 462                                         + TPOFF_K + addend;
 463 #else
 464                                 reloc_addr[1] = tls_val - def.dso->tls.offset
 465                                         + addend;
 466 #endif
 467                         }
 468 #ifdef TLSDESC_BACKWARDS
 469                         /* Some archs (32-bit ARM at least) invert the order of
 470                          * the descriptor members. Fix them up here. */
 471                         size_t tmp = reloc_addr[0];
 472                         reloc_addr[0] = reloc_addr[1];
 473                         reloc_addr[1] = tmp;
 474 #endif
 475                         break;
 476                 default:
 477                         error("Error relocating %s: unsupported relocation type %d",
 478                                 dso->name, type);
 479                         if (runtime) longjmp(*rtld_fail, 1);
 480                         continue;
 481                 }
 482         }
 483 }
 484
 485 static void redo_lazy_relocs()
 486 {
 487         struct dso *p = lazy_head, *next;
 488         lazy_head = 0;
 489         for (; p; p=next) {
 490                 next = p->lazy_next;
 491                 size_t size = p->lazy_cnt*3*sizeof(size_t);
 492                 p->lazy_cnt = 0;
 493                 do_relocs(p, p->lazy, size, 3);
 494                 if (p->lazy_cnt) {
 495                         p->lazy_next = lazy_head;
 496                         lazy_head = p;
 497                 } else {
 498                         free(p->lazy);
 499                         p->lazy = 0;
 500                         p->lazy_next = 0;
 501                 }
 502         }
 503 }
 504
 505 /* A huge hack: to make up for the wastefulness of shared libraries
 506  * needing at least a page of dirty memory even if they have no global
 507  * data, we reclaim the gaps at the beginning and end of writable maps
 508  * and "donate" them to the heap. */
 509
 510 static void reclaim(struct dso *dso, size_t start, size_t end)
 511 {
 512         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 513         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 514         if (start >= end) return;
 515         char *base = laddr_pg(dso, start);
 516         __malloc_donate(base, base+(end-start));
 517 }
 518
 519 static void reclaim_gaps(struct dso *dso)
 520 {
 521         Phdr *ph = dso->phdr;
 522         size_t phcnt = dso->phnum;
 523
 524         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 525                 if (ph->p_type!=PT_LOAD) continue;
 526                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 527                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 528                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 529                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 530         }
 531 }
 532
 533 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
 534 {
 535         static int no_map_fixed;
 536         char *q;
 537         if (!no_map_fixed) {
 538                 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
 539                 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
 540                         return q;
 541                 no_map_fixed = 1;
 542         }
 543         /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
 544         if (flags & MAP_ANONYMOUS) {
 545                 memset(p, 0, n);
 546                 return p;
 547         }
 548         ssize_t r;
 549         if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
 550         for (q=p; n; q+=r, off+=r, n-=r) {
 551                 r = read(fd, q, n);
 552                 if (r < 0 && errno != EINTR) return MAP_FAILED;
 553                 if (!r) {
 554                         memset(q, 0, n);
 555                         break;
 556                 }
 557         }
 558         return p;
 559 }
 560
 561 static void unmap_library(struct dso *dso)
 562 {
 563         if (dso->loadmap) {
 564                 size_t i;
 565                 for (i=0; i<dso->loadmap->nsegs; i++) {
 566                         if (!dso->loadmap->segs[i].p_memsz)
 567                                 continue;
 568                         munmap((void *)dso->loadmap->segs[i].addr,
 569                                 dso->loadmap->segs[i].p_memsz);
 570                 }
 571                 free(dso->loadmap);
 572         } else if (dso->map && dso->map_len) {
 573                 munmap(dso->map, dso->map_len);
 574         }
 575 }
 576
 577 static void *map_library(int fd, struct dso *dso)
 578 {
 579         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 580         void *allocated_buf=0;
 581         size_t phsize;
 582         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 583         size_t this_min, this_max;
 584         size_t nsegs = 0;
 585         off_t off_start;
 586         Ehdr *eh;
 587         Phdr *ph, *ph0;
 588         unsigned prot;
 589         unsigned char *map=MAP_FAILED, *base;
 590         size_t dyn=0;
 591         size_t tls_image=0;
 592         size_t i;
 593
 594         ssize_t l = read(fd, buf, sizeof buf);
 595         eh = buf;
 596         if (l<0) return 0;
 597         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 598                 goto noexec;
 599         phsize = eh->e_phentsize * eh->e_phnum;
 600         if (phsize > sizeof buf - sizeof *eh) {
 601                 allocated_buf = malloc(phsize);
 602                 if (!allocated_buf) return 0;
 603                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 604                 if (l < 0) goto error;
 605                 if (l != phsize) goto noexec;
 606                 ph = ph0 = allocated_buf;
 607         } else if (eh->e_phoff + phsize > l) {
 608                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 609                 if (l < 0) goto error;
 610                 if (l != phsize) goto noexec;
 611                 ph = ph0 = (void *)(buf + 1);
 612         } else {
 613                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 614         }
 615         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 616                 if (ph->p_type == PT_DYNAMIC) {
 617                         dyn = ph->p_vaddr;
 618                 } else if (ph->p_type == PT_TLS) {
 619                         tls_image = ph->p_vaddr;
 620                         dso->tls.align = ph->p_align;
 621                         dso->tls.len = ph->p_filesz;
 622                         dso->tls.size = ph->p_memsz;
 623                 } else if (ph->p_type == PT_GNU_RELRO) {
 624                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 625                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 626                 } else if (ph->p_type == PT_GNU_STACK) {
 627                         if (!runtime && ph->p_memsz > __default_stacksize) {
 628                                 __default_stacksize =
 629                                         ph->p_memsz < DEFAULT_STACK_MAX ?
 630                                         ph->p_memsz : DEFAULT_STACK_MAX;
 631                         }
 632                 }
 633                 if (ph->p_type != PT_LOAD) continue;
 634                 nsegs++;
 635                 if (ph->p_vaddr < addr_min) {
 636                         addr_min = ph->p_vaddr;
 637                         off_start = ph->p_offset;
 638                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 639                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 640                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 641                 }
 642                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 643                         addr_max = ph->p_vaddr+ph->p_memsz;
 644                 }
 645         }
 646         if (!dyn) goto noexec;
 647         if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
 648                 dso->loadmap = calloc(1, sizeof *dso->loadmap
 649                         + nsegs * sizeof *dso->loadmap->segs);
 650                 if (!dso->loadmap) goto error;
 651                 dso->loadmap->nsegs = nsegs;
 652                 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
 653                         if (ph->p_type != PT_LOAD) continue;
 654                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 655                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 656                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 657                         map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
 658                                 prot, MAP_PRIVATE,
 659                                 fd, ph->p_offset & -PAGE_SIZE);
 660                         if (map == MAP_FAILED) {
 661                                 unmap_library(dso);
 662                                 goto error;
 663                         }
 664                         dso->loadmap->segs[i].addr = (size_t)map +
 665                                 (ph->p_vaddr & PAGE_SIZE-1);
 666                         dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
 667                         dso->loadmap->segs[i].p_memsz = ph->p_memsz;
 668                         i++;
 669                         if (prot & PROT_WRITE) {
 670                                 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
 671                                         + ph->p_filesz;
 672                                 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
 673                                 size_t pgend = brk + ph->p_memsz - ph->p_filesz
 674                                         + PAGE_SIZE-1 & -PAGE_SIZE;
 675                                 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
 676                                         pgend-pgbrk, prot,
 677                                         MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
 678                                         -1, off_start) == MAP_FAILED)
 679                                         goto error;
 680                                 memset(map + brk, 0, pgbrk-brk);
 681                         }
 682                 }
 683                 map = (void *)dso->loadmap->segs[0].addr;
 684                 map_len = 0;
 685                 goto done_mapping;
 686         }
 687         addr_max += PAGE_SIZE-1;
 688         addr_max &= -PAGE_SIZE;
 689         addr_min &= -PAGE_SIZE;
 690         off_start &= -PAGE_SIZE;
 691         map_len = addr_max - addr_min + off_start;
 692         /* The first time, we map too much, possibly even more than
 693          * the length of the file. This is okay because we will not
 694          * use the invalid part; we just need to reserve the right
 695          * amount of virtual address space to map over later. */
 696         map = DL_NOMMU_SUPPORT
 697                 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
 698                         MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
 699                 : mmap((void *)addr_min, map_len, prot,
 700                         MAP_PRIVATE, fd, off_start);
 701         if (map==MAP_FAILED) goto error;
 702         dso->map = map;
 703         dso->map_len = map_len;
 704         /* If the loaded file is not relocatable and the requested address is
 705          * not available, then the load operation must fail. */
 706         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 707                 errno = EBUSY;
 708                 goto error;
 709         }
 710         base = map - addr_min;
 711         dso->phdr = 0;
 712         dso->phnum = 0;
 713         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 714                 if (ph->p_type != PT_LOAD) continue;
 715                 /* Check if the programs headers are in this load segment, and
 716                  * if so, record the address for use by dl_iterate_phdr. */
 717                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 718                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 719                         dso->phdr = (void *)(base + ph->p_vaddr
 720                                 + (eh->e_phoff-ph->p_offset));
 721                         dso->phnum = eh->e_phnum;
 722                         dso->phentsize = eh->e_phentsize;
 723                 }
 724                 this_min = ph->p_vaddr & -PAGE_SIZE;
 725                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 726                 off_start = ph->p_offset & -PAGE_SIZE;
 727                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 728                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 729                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 730                 /* Reuse the existing mapping for the lowest-address LOAD */
 731                 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
 732                         if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 733                                 goto error;
 734                 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
 735                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 736                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 737                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 738                         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)
 739                                 goto error;
 740                 }
 741         }
 742         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 743                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 744                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
 745                             && errno != ENOSYS)
 746                                 goto error;
 747                         break;
 748                 }
 749 done_mapping:
 750         dso->base = base;
 751         dso->dynv = laddr(dso, dyn);
 752         if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
 753         free(allocated_buf);
 754         return map;
 755 noexec:
 756         errno = ENOEXEC;
 757 error:
 758         if (map!=MAP_FAILED) unmap_library(dso);
 759         free(allocated_buf);
 760         return 0;
 761 }
 762
 763 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 764 {
 765         size_t l;
 766         int fd;
 767         for (;;) {
 768                 s += strspn(s, ":\n");
 769                 l = strcspn(s, ":\n");
 770                 if (l-1 >= INT_MAX) return -1;
 771                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
 772                         if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 773                         switch (errno) {
 774                         case ENOENT:
 775                         case ENOTDIR:
 776                         case EACCES:
 777                         case ENAMETOOLONG:
 778                                 break;
 779                         default:
 780                                 /* Any negative value but -1 will inhibit
 781                                  * futher path search. */
 782                                 return -2;
 783                         }
 784                 }
 785                 s += l;
 786         }
 787 }
 788
 789 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 790 {
 791         size_t n, l;
 792         const char *s, *t, *origin;
 793         char *d;
 794         if (p->rpath || !p->rpath_orig) return 0;
 795         if (!strchr(p->rpath_orig, '$')) {
 796                 p->rpath = p->rpath_orig;
 797                 return 0;
 798         }
 799         n = 0;
 800         s = p->rpath_orig;
 801         while ((t=strchr(s, '$'))) {
 802                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 803                         return 0;
 804                 s = t+1;
 805                 n++;
 806         }
 807         if (n > SSIZE_MAX/PATH_MAX) return 0;
 808
 809         if (p->kernel_mapped) {
 810                 /* $ORIGIN searches cannot be performed for the main program
 811                  * when it is suid/sgid/AT_SECURE. This is because the
 812                  * pathname is under the control of the caller of execve.
 813                  * For libraries, however, $ORIGIN can be processed safely
 814                  * since the library's pathname came from a trusted source
 815                  * (either system paths or a call to dlopen). */
 816                 if (libc.secure)
 817                         return 0;
 818                 l = readlink("/proc/self/exe", buf, buf_size);
 819                 if (l == -1) switch (errno) {
 820                 case ENOENT:
 821                 case ENOTDIR:
 822                 case EACCES:
 823                         break;
 824                 default:
 825                         return -1;
 826                 }
 827                 if (l >= buf_size)
 828                         return 0;
 829                 buf[l] = 0;
 830                 origin = buf;
 831         } else {
 832                 origin = p->name;
 833         }
 834         t = strrchr(origin, '/');
 835         if (t) {
 836                 l = t-origin;
 837         } else {
 838                 /* Normally p->name will always be an absolute or relative
 839                  * pathname containing at least one '/' character, but in the
 840                  * case where ldso was invoked as a command to execute a
 841                  * program in the working directory, app.name may not. Fix. */
 842                 origin = ".";
 843                 l = 1;
 844         }
 845         /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
 846         if (libc.secure && *origin != '/')
 847                 return 0;
 848         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 849         if (!p->rpath) return -1;
 850
 851         d = p->rpath;
 852         s = p->rpath_orig;
 853         while ((t=strchr(s, '$'))) {
 854                 memcpy(d, s, t-s);
 855                 d += t-s;
 856                 memcpy(d, origin, l);
 857                 d += l;
 858                 /* It was determined previously that the '$' is followed
 859                  * either by "ORIGIN" or "{ORIGIN}". */
 860                 s = t + 7 + 2*(t[1]=='{');
 861         }
 862         strcpy(d, s);
 863         return 0;
 864 }
 865
 866 static void decode_dyn(struct dso *p)
 867 {
 868         size_t dyn[DYN_CNT];
 869         decode_vec(p->dynv, dyn, DYN_CNT);
 870         p->syms = laddr(p, dyn[DT_SYMTAB]);
 871         p->strings = laddr(p, dyn[DT_STRTAB]);
 872         if (dyn[0]&(1<<DT_HASH))
 873                 p->hashtab = laddr(p, dyn[DT_HASH]);
 874         if (dyn[0]&(1<<DT_RPATH))
 875                 p->rpath_orig = p->strings + dyn[DT_RPATH];
 876         if (dyn[0]&(1<<DT_RUNPATH))
 877                 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
 878         if (dyn[0]&(1<<DT_PLTGOT))
 879                 p->got = laddr(p, dyn[DT_PLTGOT]);
 880         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 881                 p->ghashtab = laddr(p, *dyn);
 882         if (search_vec(p->dynv, dyn, DT_VERSYM))
 883                 p->versym = laddr(p, *dyn);
 884 }
 885
 886 static size_t count_syms(struct dso *p)
 887 {
 888         if (p->hashtab) return p->hashtab[1];
 889
 890         size_t nsym, i;
 891         uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
 892         uint32_t *hashval;
 893         for (i = nsym = 0; i < p->ghashtab[0]; i++) {
 894                 if (buckets[i] > nsym)
 895                         nsym = buckets[i];
 896         }
 897         if (nsym) {
 898                 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
 899                 do nsym++;
 900                 while (!(*hashval++ & 1));
 901         }
 902         return nsym;
 903 }
 904
 905 static void *dl_mmap(size_t n)
 906 {
 907         void *p;
 908         int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
 909 #ifdef SYS_mmap2
 910         p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
 911 #else
 912         p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
 913 #endif
 914         return p == MAP_FAILED ? 0 : p;
 915 }
 916
 917 static void makefuncdescs(struct dso *p)
 918 {
 919         static int self_done;
 920         size_t nsym = count_syms(p);
 921         size_t i, size = nsym * sizeof(*p->funcdescs);
 922
 923         if (!self_done) {
 924                 p->funcdescs = dl_mmap(size);
 925                 self_done = 1;
 926         } else {
 927                 p->funcdescs = malloc(size);
 928         }
 929         if (!p->funcdescs) {
 930                 if (!runtime) a_crash();
 931                 error("Error allocating function descriptors for %s", p->name);
 932                 longjmp(*rtld_fail, 1);
 933         }
 934         for (i=0; i<nsym; i++) {
 935                 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
 936                         p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
 937                         p->funcdescs[i].got = p->got;
 938                 } else {
 939                         p->funcdescs[i].addr = 0;
 940                         p->funcdescs[i].got = 0;
 941                 }
 942         }
 943 }
 944
 945 static struct dso *load_library(const char *name, struct dso *needed_by)
 946 {
 947         char buf[2*NAME_MAX+2];
 948         const char *pathname;
 949         unsigned char *map;
 950         struct dso *p, temp_dso = {0};
 951         int fd;
 952         struct stat st;
 953         size_t alloc_size;
 954         int n_th = 0;
 955         int is_self = 0;
 956
 957         if (!*name) {
 958                 errno = EINVAL;
 959                 return 0;
 960         }
 961
 962         /* Catch and block attempts to reload the implementation itself */
 963         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 964                 static const char reserved[] =
 965                         "c.pthread.rt.m.dl.util.xnet.";
 966                 const char *rp, *next;
 967                 for (rp=reserved; *rp; rp=next) {
 968                         next = strchr(rp, '.') + 1;
 969                         if (strncmp(name+3, rp, next-rp) == 0)
 970                                 break;
 971                 }
 972                 if (*rp) {
 973                         if (ldd_mode) {
 974                                 /* Track which names have been resolved
 975                                  * and only report each one once. */
 976                                 static unsigned reported;
 977                                 unsigned mask = 1U<<(rp-reserved);
 978                                 if (!(reported & mask)) {
 979                                         reported |= mask;
 980                                         dprintf(1, "\t%s => %s (%p)\n",
 981                                                 name, ldso.name,
 982                                                 ldso.base);
 983                                 }
 984                         }
 985                         is_self = 1;
 986                 }
 987         }
 988         if (!strcmp(name, ldso.name)) is_self = 1;
 989         if (is_self) {
 990                 if (!ldso.prev) {
 991                         tail->next = &ldso;
 992                         ldso.prev = tail;
 993                         tail = &ldso;
 994                 }
 995                 return &ldso;
 996         }
 997         if (strchr(name, '/')) {
 998                 pathname = name;
 999                 fd = open(name, O_RDONLY|O_CLOEXEC);
1000         } else {
1001                 /* Search for the name to see if it's already loaded */
1002                 for (p=head->next; p; p=p->next) {
1003                         if (p->shortname && !strcmp(p->shortname, name)) {
1004                                 return p;
1005                         }
1006                 }
1007                 if (strlen(name) > NAME_MAX) return 0;
1008                 fd = -1;
1009                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1010                 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1011                         if (fixup_rpath(p, buf, sizeof buf) < 0)
1012                                 fd = -2; /* Inhibit further search. */
1013                         if (p->rpath)
1014                                 fd = path_open(name, p->rpath, buf, sizeof buf);
1015                 }
1016                 if (fd == -1) {
1017                         if (!sys_path) {
1018                                 char *prefix = 0;
1019                                 size_t prefix_len;
1020                                 if (ldso.name[0]=='/') {
1021                                         char *s, *t, *z;
1022                                         for (s=t=z=ldso.name; *s; s++)
1023                                                 if (*s=='/') z=t, t=s;
1024                                         prefix_len = z-ldso.name;
1025                                         if (prefix_len < PATH_MAX)
1026                                                 prefix = ldso.name;
1027                                 }
1028                                 if (!prefix) {
1029                                         prefix = "";
1030                                         prefix_len = 0;
1031                                 }
1032                                 char etc_ldso_path[prefix_len + 1
1033                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1034                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1035                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1036                                         (int)prefix_len, prefix);
1037                                 FILE *f = fopen(etc_ldso_path, "rbe");
1038                                 if (f) {
1039                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1040                                                 free(sys_path);
1041                                                 sys_path = "";
1042                                         }
1043                                         fclose(f);
1044                                 } else if (errno != ENOENT) {
1045                                         sys_path = "";
1046                                 }
1047                         }
1048                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1049                         fd = path_open(name, sys_path, buf, sizeof buf);
1050                 }
1051                 pathname = buf;
1052         }
1053         if (fd < 0) return 0;
1054         if (fstat(fd, &st) < 0) {
1055                 close(fd);
1056                 return 0;
1057         }
1058         for (p=head->next; p; p=p->next) {
1059                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1060                         /* If this library was previously loaded with a
1061                          * pathname but a search found the same inode,
1062                          * setup its shortname so it can be found by name. */
1063                         if (!p->shortname && pathname != name)
1064                                 p->shortname = strrchr(p->name, '/')+1;
1065                         close(fd);
1066                         return p;
1067                 }
1068         }
1069         map = noload ? 0 : map_library(fd, &temp_dso);
1070         close(fd);
1071         if (!map) return 0;
1072
1073         /* Avoid the danger of getting two versions of libc mapped into the
1074          * same process when an absolute pathname was used. The symbols
1075          * checked are chosen to catch both musl and glibc, and to avoid
1076          * false positives from interposition-hack libraries. */
1077         decode_dyn(&temp_dso);
1078         if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1079             find_sym(&temp_dso, "stdin", 1).sym) {
1080                 unmap_library(&temp_dso);
1081                 return load_library("libc.so", needed_by);
1082         }
1083         /* Past this point, if we haven't reached runtime yet, ldso has
1084          * committed either to use the mapped library or to abort execution.
1085          * Unmapping is not possible, so we can safely reclaim gaps. */
1086         if (!runtime) reclaim_gaps(&temp_dso);
1087
1088         /* Allocate storage for the new DSO. When there is TLS, this
1089          * storage must include a reservation for all pre-existing
1090          * threads to obtain copies of both the new TLS, and an
1091          * extended DTV capable of storing an additional slot for
1092          * the newly-loaded DSO. */
1093         alloc_size = sizeof *p + strlen(pathname) + 1;
1094         if (runtime && temp_dso.tls.image) {
1095                 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1096                         + sizeof(void *) * (tls_cnt+3);
1097                 n_th = libc.threads_minus_1 + 1;
1098                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1099                 else alloc_size += n_th * per_th;
1100         }
1101         p = calloc(1, alloc_size);
1102         if (!p) {
1103                 unmap_library(&temp_dso);
1104                 return 0;
1105         }
1106         memcpy(p, &temp_dso, sizeof temp_dso);
1107         p->dev = st.st_dev;
1108         p->ino = st.st_ino;
1109         p->needed_by = needed_by;
1110         p->name = p->buf;
1111         p->runtime_loaded = runtime;
1112         strcpy(p->name, pathname);
1113         /* Add a shortname only if name arg was not an explicit pathname. */
1114         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1115         if (p->tls.image) {
1116                 p->tls_id = ++tls_cnt;
1117                 tls_align = MAXP2(tls_align, p->tls.align);
1118 #ifdef TLS_ABOVE_TP
1119                 p->tls.offset = tls_offset + ( (tls_align-1) &
1120                         -(tls_offset + (uintptr_t)p->tls.image) );
1121                 tls_offset += p->tls.size;
1122 #else
1123                 tls_offset += p->tls.size + p->tls.align - 1;
1124                 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1125                         & (p->tls.align-1);
1126                 p->tls.offset = tls_offset;
1127 #endif
1128                 p->new_dtv = (void *)(-sizeof(size_t) &
1129                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1130                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1131                 if (tls_tail) tls_tail->next = &p->tls;
1132                 else libc.tls_head = &p->tls;
1133                 tls_tail = &p->tls;
1134         }
1135
1136         tail->next = p;
1137         p->prev = tail;
1138         tail = p;
1139
1140         if (DL_FDPIC) makefuncdescs(p);
1141
1142         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1143
1144         return p;
1145 }
1146
1147 static void load_direct_deps(struct dso *p)
1148 {
1149         size_t i, cnt=0;
1150         if (p->deps) return;
1151         /* For head, all preloads are direct pseudo-dependencies.
1152          * Count and include them now to avoid realloc later. */
1153         if (p==head) for (struct dso *q=p->next; q; q=q->next)
1154                 cnt++;
1155         for (i=0; p->dynv[i]; i+=2)
1156                 if (p->dynv[i] == DT_NEEDED) cnt++;
1157         p->deps = calloc(cnt+1, sizeof *p->deps);
1158         if (!p->deps) {
1159                 error("Error loading dependencies for %s", p->name);
1160                 if (runtime) longjmp(*rtld_fail, 1);
1161         }
1162         cnt=0;
1163         if (p==head) for (struct dso *q=p->next; q; q=q->next)
1164                 p->deps[cnt++] = q;
1165         for (i=0; p->dynv[i]; i+=2) {
1166                 if (p->dynv[i] != DT_NEEDED) continue;
1167                 struct dso *dep = load_library(p->strings + p->dynv[i+1], p);
1168                 if (!dep) {
1169                         error("Error loading shared library %s: %m (needed by %s)",
1170                                 p->strings + p->dynv[i+1], p->name);
1171                         if (runtime) longjmp(*rtld_fail, 1);
1172                         continue;
1173                 }
1174                 p->deps[cnt++] = dep;
1175         }
1176         p->deps[cnt] = 0;
1177         p->ndeps_direct = cnt;
1178 }
1179
1180 static void load_deps(struct dso *p)
1181 {
1182         if (p->deps) return;
1183         for (; p; p=p->next)
1184                 load_direct_deps(p);
1185 }
1186
1187 static void extend_bfs_deps(struct dso *p)
1188 {
1189         size_t i, j, cnt, ndeps_all;
1190         struct dso **tmp;
1191
1192         /* Can't use realloc if the original p->deps was allocated at
1193          * program entry and malloc has been replaced. */
1194         int no_realloc = __malloc_replaced && !p->runtime_loaded;
1195
1196         if (p->bfs_built) return;
1197         ndeps_all = p->ndeps_direct;
1198
1199         /* Mark existing (direct) deps so they won't be duplicated. */
1200         for (i=0; p->deps[i]; i++)
1201                 p->deps[i]->mark = 1;
1202
1203         /* For each dependency already in the list, copy its list of direct
1204          * dependencies to the list, excluding any items already in the
1205          * list. Note that the list this loop iterates over will grow during
1206          * the loop, but since duplicates are excluded, growth is bounded. */
1207         for (i=0; p->deps[i]; i++) {
1208                 struct dso *dep = p->deps[i];
1209                 for (j=cnt=0; j<dep->ndeps_direct; j++)
1210                         if (!dep->deps[j]->mark) cnt++;
1211                 tmp = no_realloc ?
1212                         malloc(sizeof(*tmp) * (ndeps_all+cnt+1)) :
1213                         realloc(p->deps, sizeof(*tmp) * (ndeps_all+cnt+1));
1214                 if (!tmp) {
1215                         error("Error recording dependencies for %s", p->name);
1216                         if (runtime) longjmp(*rtld_fail, 1);
1217                         continue;
1218                 }
1219                 if (no_realloc) {
1220                         memcpy(tmp, p->deps, sizeof(*tmp) * (ndeps_all+1));
1221                         no_realloc = 0;
1222                 }
1223                 p->deps = tmp;
1224                 for (j=0; j<dep->ndeps_direct; j++) {
1225                         if (dep->deps[j]->mark) continue;
1226                         dep->deps[j]->mark = 1;
1227                         p->deps[ndeps_all++] = dep->deps[j];
1228                 }
1229                 p->deps[ndeps_all] = 0;
1230         }
1231         p->bfs_built = 1;
1232         for (p=head; p; p=p->next)
1233                 p->mark = 0;
1234 }
1235
1236 static void load_preload(char *s)
1237 {
1238         int tmp;
1239         char *z;
1240         for (z=s; *z; s=z) {
1241                 for (   ; *s && (isspace(*s) || *s==':'); s++);
1242                 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1243                 tmp = *z;
1244                 *z = 0;
1245                 load_library(s, 0);
1246                 *z = tmp;
1247         }
1248 }
1249
1250 static void add_syms(struct dso *p)
1251 {
1252         if (!p->syms_next && syms_tail != p) {
1253                 syms_tail->syms_next = p;
1254                 syms_tail = p;
1255         }
1256 }
1257
1258 static void revert_syms(struct dso *old_tail)
1259 {
1260         struct dso *p, *next;
1261         /* Chop off the tail of the list of dsos that participate in
1262          * the global symbol table, reverting them to RTLD_LOCAL. */
1263         for (p=old_tail; p; p=next) {
1264                 next = p->syms_next;
1265                 p->syms_next = 0;
1266         }
1267         syms_tail = old_tail;
1268 }
1269
1270 static void do_mips_relocs(struct dso *p, size_t *got)
1271 {
1272         size_t i, j, rel[2];
1273         unsigned char *base = p->base;
1274         i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1275         if (p==&ldso) {
1276                 got += i;
1277         } else {
1278                 while (i--) *got++ += (size_t)base;
1279         }
1280         j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1281         i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1282         Sym *sym = p->syms + j;
1283         rel[0] = (unsigned char *)got - base;
1284         for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1285                 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1286                 do_relocs(p, rel, sizeof rel, 2);
1287         }
1288 }
1289
1290 static void reloc_all(struct dso *p)
1291 {
1292         size_t dyn[DYN_CNT];
1293         for (; p; p=p->next) {
1294                 if (p->relocated) continue;
1295                 decode_vec(p->dynv, dyn, DYN_CNT);
1296                 if (NEED_MIPS_GOT_RELOCS)
1297                         do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1298                 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1299                         2+(dyn[DT_PLTREL]==DT_RELA));
1300                 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1301                 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1302
1303                 if (head != &ldso && p->relro_start != p->relro_end &&
1304                     mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1305                     && errno != ENOSYS) {
1306                         error("Error relocating %s: RELRO protection failed: %m",
1307                                 p->name);
1308                         if (runtime) longjmp(*rtld_fail, 1);
1309                 }
1310
1311                 p->relocated = 1;
1312         }
1313 }
1314
1315 static void kernel_mapped_dso(struct dso *p)
1316 {
1317         size_t min_addr = -1, max_addr = 0, cnt;
1318         Phdr *ph = p->phdr;
1319         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1320                 if (ph->p_type == PT_DYNAMIC) {
1321                         p->dynv = laddr(p, ph->p_vaddr);
1322                 } else if (ph->p_type == PT_GNU_RELRO) {
1323                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1324                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1325                 } else if (ph->p_type == PT_GNU_STACK) {
1326                         if (!runtime && ph->p_memsz > __default_stacksize) {
1327                                 __default_stacksize =
1328                                         ph->p_memsz < DEFAULT_STACK_MAX ?
1329                                         ph->p_memsz : DEFAULT_STACK_MAX;
1330                         }
1331                 }
1332                 if (ph->p_type != PT_LOAD) continue;
1333                 if (ph->p_vaddr < min_addr)
1334                         min_addr = ph->p_vaddr;
1335                 if (ph->p_vaddr+ph->p_memsz > max_addr)
1336                         max_addr = ph->p_vaddr+ph->p_memsz;
1337         }
1338         min_addr &= -PAGE_SIZE;
1339         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1340         p->map = p->base + min_addr;
1341         p->map_len = max_addr - min_addr;
1342         p->kernel_mapped = 1;
1343 }
1344
1345 void __libc_exit_fini()
1346 {
1347         struct dso *p;
1348         size_t dyn[DYN_CNT];
1349         for (p=fini_head; p; p=p->fini_next) {
1350                 if (!p->constructed) continue;
1351                 decode_vec(p->dynv, dyn, DYN_CNT);
1352                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1353                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1354                         size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1355                         while (n--) ((void (*)(void))*--fn)();
1356                 }
1357 #ifndef NO_LEGACY_INITFINI
1358                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1359                         fpaddr(p, dyn[DT_FINI])();
1360 #endif
1361         }
1362 }
1363
1364 static void do_init_fini(struct dso *p)
1365 {
1366         size_t dyn[DYN_CNT];
1367         int need_locking = libc.threads_minus_1;
1368         /* Allow recursive calls that arise when a library calls
1369          * dlopen from one of its constructors, but block any
1370          * other threads until all ctors have finished. */
1371         if (need_locking) pthread_mutex_lock(&init_fini_lock);
1372         for (; p; p=p->prev) {
1373                 if (p->constructed) continue;
1374                 p->constructed = 1;
1375                 decode_vec(p->dynv, dyn, DYN_CNT);
1376                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1377                         p->fini_next = fini_head;
1378                         fini_head = p;
1379                 }
1380 #ifndef NO_LEGACY_INITFINI
1381                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1382                         fpaddr(p, dyn[DT_INIT])();
1383 #endif
1384                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1385                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1386                         size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1387                         while (n--) ((void (*)(void))*fn++)();
1388                 }
1389                 if (!need_locking && libc.threads_minus_1) {
1390                         need_locking = 1;
1391                         pthread_mutex_lock(&init_fini_lock);
1392                 }
1393         }
1394         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1395 }
1396
1397 void __libc_start_init(void)
1398 {
1399         do_init_fini(tail);
1400 }
1401
1402 static void dl_debug_state(void)
1403 {
1404 }
1405
1406 weak_alias(dl_debug_state, _dl_debug_state);
1407
1408 void __init_tls(size_t *auxv)
1409 {
1410 }
1411
1412 static void update_tls_size()
1413 {
1414         libc.tls_cnt = tls_cnt;
1415         libc.tls_align = tls_align;
1416         libc.tls_size = ALIGN(
1417                 (1+tls_cnt) * sizeof(void *) +
1418                 tls_offset +
1419                 sizeof(struct pthread) +
1420                 tls_align * 2,
1421         tls_align);
1422 }
1423
1424 static void install_new_tls(void)
1425 {
1426         sigset_t set;
1427         pthread_t self = __pthread_self(), td;
1428         struct dso *dtv_provider = container_of(tls_tail, struct dso, tls);
1429         uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv;
1430         struct dso *p;
1431         size_t i, j;
1432         size_t old_cnt = self->dtv[0];
1433
1434         __block_app_sigs(&set);
1435         __tl_lock();
1436         /* Copy existing dtv contents from all existing threads. */
1437         for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1438                 memcpy(newdtv+i, td->dtv,
1439                         (old_cnt+1)*sizeof(uintptr_t));
1440                 newdtv[i][0] = tls_cnt;
1441         }
1442         /* Install new dtls into the enlarged, uninstalled dtv copies. */
1443         for (p=head; ; p=p->next) {
1444                 if (p->tls_id <= old_cnt) continue;
1445                 unsigned char *mem = p->new_tls;
1446                 for (j=0; j<i; j++) {
1447                         unsigned char *new = mem;
1448                         new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1449                                 & (p->tls.align-1);
1450                         memcpy(new, p->tls.image, p->tls.len);
1451                         newdtv[j][p->tls_id] =
1452                                 (uintptr_t)new + DTP_OFFSET;
1453                         mem += p->tls.size + p->tls.align;
1454                 }
1455                 if (p->tls_id == tls_cnt) break;
1456         }
1457
1458         /* Broadcast barrier to ensure contents of new dtv is visible
1459          * if the new dtv pointer is. The __membarrier function has a
1460          * fallback emulation using signals for kernels that lack the
1461          * feature at the syscall level. */
1462
1463         __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1464
1465         /* Install new dtv for each thread. */
1466         for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1467                 td->dtv = td->dtv_copy = newdtv[j];
1468         }
1469
1470         __tl_unlock();
1471         __restore_sigs(&set);
1472 }
1473
1474 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1475  * following stage 2 and stage 3 functions via primitive symbolic lookup
1476  * since it does not have access to their addresses to begin with. */
1477
1478 /* Stage 2 of the dynamic linker is called after relative relocations
1479  * have been processed. It can make function calls to static functions
1480  * and access string literals and static data, but cannot use extern
1481  * symbols. Its job is to perform symbolic relocations on the dynamic
1482  * linker itself, but some of the relocations performed may need to be
1483  * replaced later due to copy relocations in the main program. */
1484
1485 hidden void __dls2(unsigned char *base, size_t *sp)
1486 {
1487         if (DL_FDPIC) {
1488                 void *p1 = (void *)sp[-2];
1489                 void *p2 = (void *)sp[-1];
1490                 if (!p1) {
1491                         size_t *auxv, aux[AUX_CNT];
1492                         for (auxv=sp+1+*sp+1; *auxv; auxv++);
1493                         auxv++;
1494                         decode_vec(auxv, aux, AUX_CNT);
1495                         if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1496                         else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1497                 }
1498                 app_loadmap = p2 ? p1 : 0;
1499                 ldso.loadmap = p2 ? p2 : p1;
1500                 ldso.base = laddr(&ldso, 0);
1501         } else {
1502                 ldso.base = base;
1503         }
1504         Ehdr *ehdr = (void *)ldso.base;
1505         ldso.name = ldso.shortname = "libc.so";
1506         ldso.phnum = ehdr->e_phnum;
1507         ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1508         ldso.phentsize = ehdr->e_phentsize;
1509         kernel_mapped_dso(&ldso);
1510         decode_dyn(&ldso);
1511
1512         if (DL_FDPIC) makefuncdescs(&ldso);
1513
1514         /* Prepare storage for to save clobbered REL addends so they
1515          * can be reused in stage 3. There should be very few. If
1516          * something goes wrong and there are a huge number, abort
1517          * instead of risking stack overflow. */
1518         size_t dyn[DYN_CNT];
1519         decode_vec(ldso.dynv, dyn, DYN_CNT);
1520         size_t *rel = laddr(&ldso, dyn[DT_REL]);
1521         size_t rel_size = dyn[DT_RELSZ];
1522         size_t symbolic_rel_cnt = 0;
1523         apply_addends_to = rel;
1524         for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1525                 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1526         if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1527         size_t addends[symbolic_rel_cnt+1];
1528         saved_addends = addends;
1529
1530         head = &ldso;
1531         reloc_all(&ldso);
1532
1533         ldso.relocated = 0;
1534
1535         /* Call dynamic linker stage-2b, __dls2b, looking it up
1536          * symbolically as a barrier against moving the address
1537          * load across the above relocation processing. */
1538         struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1539         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp);
1540         else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp);
1541 }
1542
1543 /* Stage 2b sets up a valid thread pointer, which requires relocations
1544  * completed in stage 2, and on which stage 3 is permitted to depend.
1545  * This is done as a separate stage, with symbolic lookup as a barrier,
1546  * so that loads of the thread pointer and &errno can be pure/const and
1547  * thereby hoistable. */
1548
1549 _Noreturn void __dls2b(size_t *sp)
1550 {
1551         /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1552          * use during dynamic linking. If possible it will also serve as the
1553          * thread pointer at runtime. */
1554         libc.tls_size = sizeof builtin_tls;
1555         libc.tls_align = tls_align;
1556         if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1557                 a_crash();
1558         }
1559
1560         struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1561         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1562         else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1563 }
1564
1565 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1566  * fully functional. Its job is to load (if not already loaded) and
1567  * process dependencies and relocations for the main application and
1568  * transfer control to its entry point. */
1569
1570 _Noreturn void __dls3(size_t *sp)
1571 {
1572         static struct dso app, vdso;
1573         size_t aux[AUX_CNT], *auxv;
1574         size_t i;
1575         char *env_preload=0;
1576         char *replace_argv0=0;
1577         size_t vdso_base;
1578         int argc = *sp;
1579         char **argv = (void *)(sp+1);
1580         char **argv_orig = argv;
1581         char **envp = argv+argc+1;
1582
1583         /* Find aux vector just past environ[] and use it to initialize
1584          * global data that may be needed before we can make syscalls. */
1585         __environ = envp;
1586         for (i=argc+1; argv[i]; i++);
1587         libc.auxv = auxv = (void *)(argv+i+1);
1588         decode_vec(auxv, aux, AUX_CNT);
1589         __hwcap = aux[AT_HWCAP];
1590         libc.page_size = aux[AT_PAGESZ];
1591         libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1592                 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1593
1594         /* Only trust user/env if kernel says we're not suid/sgid */
1595         if (!libc.secure) {
1596                 env_path = getenv("LD_LIBRARY_PATH");
1597                 env_preload = getenv("LD_PRELOAD");
1598         }
1599
1600         /* If the main program was already loaded by the kernel,
1601          * AT_PHDR will point to some location other than the dynamic
1602          * linker's program headers. */
1603         if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1604                 size_t interp_off = 0;
1605                 size_t tls_image = 0;
1606                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1607                 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1608                 app.phnum = aux[AT_PHNUM];
1609                 app.phentsize = aux[AT_PHENT];
1610                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1611                         if (phdr->p_type == PT_PHDR)
1612                                 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1613                         else if (phdr->p_type == PT_INTERP)
1614                                 interp_off = (size_t)phdr->p_vaddr;
1615                         else if (phdr->p_type == PT_TLS) {
1616                                 tls_image = phdr->p_vaddr;
1617                                 app.tls.len = phdr->p_filesz;
1618                                 app.tls.size = phdr->p_memsz;
1619                                 app.tls.align = phdr->p_align;
1620                         }
1621                 }
1622                 if (DL_FDPIC) app.loadmap = app_loadmap;
1623                 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1624                 if (interp_off) ldso.name = laddr(&app, interp_off);
1625                 if ((aux[0] & (1UL<<AT_EXECFN))
1626                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1627                         app.name = (char *)aux[AT_EXECFN];
1628                 else
1629                         app.name = argv[0];
1630                 kernel_mapped_dso(&app);
1631         } else {
1632                 int fd;
1633                 char *ldname = argv[0];
1634                 size_t l = strlen(ldname);
1635                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1636                 argv++;
1637                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1638                         char *opt = argv[0]+2;
1639                         *argv++ = (void *)-1;
1640                         if (!*opt) {
1641                                 break;
1642                         } else if (!memcmp(opt, "list", 5)) {
1643                                 ldd_mode = 1;
1644                         } else if (!memcmp(opt, "library-path", 12)) {
1645                                 if (opt[12]=='=') env_path = opt+13;
1646                                 else if (opt[12]) *argv = 0;
1647                                 else if (*argv) env_path = *argv++;
1648                         } else if (!memcmp(opt, "preload", 7)) {
1649                                 if (opt[7]=='=') env_preload = opt+8;
1650                                 else if (opt[7]) *argv = 0;
1651                                 else if (*argv) env_preload = *argv++;
1652                         } else if (!memcmp(opt, "argv0", 5)) {
1653                                 if (opt[5]=='=') replace_argv0 = opt+6;
1654                                 else if (opt[5]) *argv = 0;
1655                                 else if (*argv) replace_argv0 = *argv++;
1656                         } else {
1657                                 argv[0] = 0;
1658                         }
1659                 }
1660                 argv[-1] = (void *)(argc - (argv-argv_orig));
1661                 if (!argv[0]) {
1662                         dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1663                                 "Version %s\n"
1664                                 "Dynamic Program Loader\n"
1665                                 "Usage: %s [options] [--] pathname%s\n",
1666                                 __libc_version, ldname,
1667                                 ldd_mode ? "" : " [args]");
1668                         _exit(1);
1669                 }
1670                 fd = open(argv[0], O_RDONLY);
1671                 if (fd < 0) {
1672                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1673                         _exit(1);
1674                 }
1675                 Ehdr *ehdr = (void *)map_library(fd, &app);
1676                 if (!ehdr) {
1677                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1678                         _exit(1);
1679                 }
1680                 close(fd);
1681                 ldso.name = ldname;
1682                 app.name = argv[0];
1683                 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1684                 /* Find the name that would have been used for the dynamic
1685                  * linker had ldd not taken its place. */
1686                 if (ldd_mode) {
1687                         for (i=0; i<app.phnum; i++) {
1688                                 if (app.phdr[i].p_type == PT_INTERP)
1689                                         ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1690                         }
1691                         dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1692                 }
1693         }
1694         if (app.tls.size) {
1695                 libc.tls_head = tls_tail = &app.tls;
1696                 app.tls_id = tls_cnt = 1;
1697 #ifdef TLS_ABOVE_TP
1698                 app.tls.offset = GAP_ABOVE_TP;
1699                 app.tls.offset += -GAP_ABOVE_TP & (app.tls.align-1);
1700                 tls_offset = app.tls.offset + app.tls.size
1701                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1702                         & (app.tls.align-1) );
1703 #else
1704                 tls_offset = app.tls.offset = app.tls.size
1705                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1706                         & (app.tls.align-1) );
1707 #endif
1708                 tls_align = MAXP2(tls_align, app.tls.align);
1709         }
1710         decode_dyn(&app);
1711         if (DL_FDPIC) {
1712                 makefuncdescs(&app);
1713                 if (!app.loadmap) {
1714                         app.loadmap = (void *)&app_dummy_loadmap;
1715                         app.loadmap->nsegs = 1;
1716                         app.loadmap->segs[0].addr = (size_t)app.map;
1717                         app.loadmap->segs[0].p_vaddr = (size_t)app.map
1718                                 - (size_t)app.base;
1719                         app.loadmap->segs[0].p_memsz = app.map_len;
1720                 }
1721                 argv[-3] = (void *)app.loadmap;
1722         }
1723
1724         /* Initial dso chain consists only of the app. */
1725         head = tail = syms_tail = &app;
1726
1727         /* Donate unused parts of app and library mapping to malloc */
1728         reclaim_gaps(&app);
1729         reclaim_gaps(&ldso);
1730
1731         /* Load preload/needed libraries, add symbols to global namespace. */
1732         if (env_preload) load_preload(env_preload);
1733         load_deps(&app);
1734         for (struct dso *p=head; p; p=p->next)
1735                 add_syms(p);
1736
1737         /* Attach to vdso, if provided by the kernel, last so that it does
1738          * not become part of the global namespace.  */
1739         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1740                 Ehdr *ehdr = (void *)vdso_base;
1741                 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1742                 vdso.phnum = ehdr->e_phnum;
1743                 vdso.phentsize = ehdr->e_phentsize;
1744                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1745                         if (phdr->p_type == PT_DYNAMIC)
1746                                 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1747                         if (phdr->p_type == PT_LOAD)
1748                                 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1749                 }
1750                 vdso.name = "";
1751                 vdso.shortname = "linux-gate.so.1";
1752                 vdso.relocated = 1;
1753                 decode_dyn(&vdso);
1754                 vdso.prev = tail;
1755                 tail->next = &vdso;
1756                 tail = &vdso;
1757         }
1758
1759         for (i=0; app.dynv[i]; i+=2) {
1760                 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1761                         app.dynv[i+1] = (size_t)&debug;
1762                 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1763                         size_t *ptr = (size_t *) app.dynv[i+1];
1764                         *ptr = (size_t)&debug;
1765                 }
1766         }
1767
1768         /* The main program must be relocated LAST since it may contin
1769          * copy relocations which depend on libraries' relocations. */
1770         reloc_all(app.next);
1771         reloc_all(&app);
1772
1773         update_tls_size();
1774         if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1775                 void *initial_tls = calloc(libc.tls_size, 1);
1776                 if (!initial_tls) {
1777                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1778                                 argv[0], libc.tls_size);
1779                         _exit(127);
1780                 }
1781                 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1782                         a_crash();
1783                 }
1784         } else {
1785                 size_t tmp_tls_size = libc.tls_size;
1786                 pthread_t self = __pthread_self();
1787                 /* Temporarily set the tls size to the full size of
1788                  * builtin_tls so that __copy_tls will use the same layout
1789                  * as it did for before. Then check, just to be safe. */
1790                 libc.tls_size = sizeof builtin_tls;
1791                 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1792                 libc.tls_size = tmp_tls_size;
1793         }
1794         static_tls_cnt = tls_cnt;
1795
1796         if (ldso_fail) _exit(127);
1797         if (ldd_mode) _exit(0);
1798
1799         /* Determine if malloc was interposed by a replacement implementation
1800          * so that calloc and the memalign family can harden against the
1801          * possibility of incomplete replacement. */
1802         if (find_sym(head, "malloc", 1).dso != &ldso)
1803                 __malloc_replaced = 1;
1804
1805         /* Switch to runtime mode: any further failures in the dynamic
1806          * linker are a reportable failure rather than a fatal startup
1807          * error. */
1808         runtime = 1;
1809
1810         debug.ver = 1;
1811         debug.bp = dl_debug_state;
1812         debug.head = head;
1813         debug.base = ldso.base;
1814         debug.state = 0;
1815         _dl_debug_state();
1816
1817         if (replace_argv0) argv[0] = replace_argv0;
1818
1819         errno = 0;
1820
1821         CRTJMP((void *)aux[AT_ENTRY], argv-1);
1822         for(;;);
1823 }
1824
1825 static void prepare_lazy(struct dso *p)
1826 {
1827         size_t dyn[DYN_CNT], n, flags1=0;
1828         decode_vec(p->dynv, dyn, DYN_CNT);
1829         search_vec(p->dynv, &flags1, DT_FLAGS_1);
1830         if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1831                 return;
1832         n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1833         if (NEED_MIPS_GOT_RELOCS) {
1834                 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1835                 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1836                 n += i-j;
1837         }
1838         p->lazy = calloc(n, 3*sizeof(size_t));
1839         if (!p->lazy) {
1840                 error("Error preparing lazy relocation for %s: %m", p->name);
1841                 longjmp(*rtld_fail, 1);
1842         }
1843         p->lazy_next = lazy_head;
1844         lazy_head = p;
1845 }
1846
1847 void *dlopen(const char *file, int mode)
1848 {
1849         struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1850         struct tls_module *orig_tls_tail;
1851         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1852         size_t i;
1853         int cs;
1854         jmp_buf jb;
1855
1856         if (!file) return head;
1857
1858         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1859         pthread_rwlock_wrlock(&lock);
1860         __inhibit_ptc();
1861
1862         p = 0;
1863         orig_tls_tail = tls_tail;
1864         orig_tls_cnt = tls_cnt;
1865         orig_tls_offset = tls_offset;
1866         orig_tls_align = tls_align;
1867         orig_lazy_head = lazy_head;
1868         orig_syms_tail = syms_tail;
1869         orig_tail = tail;
1870         noload = mode & RTLD_NOLOAD;
1871
1872         rtld_fail = &jb;
1873         if (setjmp(*rtld_fail)) {
1874                 /* Clean up anything new that was (partially) loaded */
1875                 revert_syms(orig_syms_tail);
1876                 for (p=orig_tail->next; p; p=next) {
1877                         next = p->next;
1878                         while (p->td_index) {
1879                                 void *tmp = p->td_index->next;
1880                                 free(p->td_index);
1881                                 p->td_index = tmp;
1882                         }
1883                         free(p->funcdescs);
1884                         if (p->rpath != p->rpath_orig)
1885                                 free(p->rpath);
1886                         free(p->deps);
1887                         unmap_library(p);
1888                         free(p);
1889                 }
1890                 if (!orig_tls_tail) libc.tls_head = 0;
1891                 tls_tail = orig_tls_tail;
1892                 if (tls_tail) tls_tail->next = 0;
1893                 tls_cnt = orig_tls_cnt;
1894                 tls_offset = orig_tls_offset;
1895                 tls_align = orig_tls_align;
1896                 lazy_head = orig_lazy_head;
1897                 tail = orig_tail;
1898                 tail->next = 0;
1899                 p = 0;
1900                 goto end;
1901         } else p = load_library(file, head);
1902
1903         if (!p) {
1904                 error(noload ?
1905                         "Library %s is not already loaded" :
1906                         "Error loading shared library %s: %m",
1907                         file);
1908                 goto end;
1909         }
1910
1911         /* First load handling */
1912         load_deps(p);
1913         extend_bfs_deps(p);
1914         if (!p->relocated && (mode & RTLD_LAZY)) {
1915                 prepare_lazy(p);
1916                 for (i=0; p->deps[i]; i++)
1917                         if (!p->deps[i]->relocated)
1918                                 prepare_lazy(p->deps[i]);
1919         }
1920         if (!p->relocated || (mode & RTLD_GLOBAL)) {
1921                 /* Make new symbols global, at least temporarily, so we can do
1922                  * relocations. If not RTLD_GLOBAL, this is reverted below. */
1923                 add_syms(p);
1924                 for (i=0; p->deps[i]; i++)
1925                         add_syms(p->deps[i]);
1926         }
1927         if (!p->relocated) {
1928                 reloc_all(p);
1929         }
1930
1931         /* If RTLD_GLOBAL was not specified, undo any new additions
1932          * to the global symbol table. This is a nop if the library was
1933          * previously loaded and already global. */
1934         if (!(mode & RTLD_GLOBAL))
1935                 revert_syms(orig_syms_tail);
1936
1937         /* Processing of deferred lazy relocations must not happen until
1938          * the new libraries are committed; otherwise we could end up with
1939          * relocations resolved to symbol definitions that get removed. */
1940         redo_lazy_relocs();
1941
1942         update_tls_size();
1943         if (tls_cnt != orig_tls_cnt)
1944                 install_new_tls();
1945         _dl_debug_state();
1946         orig_tail = tail;
1947 end:
1948         __release_ptc();
1949         if (p) gencnt++;
1950         pthread_rwlock_unlock(&lock);
1951         if (p) do_init_fini(orig_tail);
1952         pthread_setcancelstate(cs, 0);
1953         return p;
1954 }
1955
1956 hidden int __dl_invalid_handle(void *h)
1957 {
1958         struct dso *p;
1959         for (p=head; p; p=p->next) if (h==p) return 0;
1960         error("Invalid library handle %p", (void *)h);
1961         return 1;
1962 }
1963
1964 static void *addr2dso(size_t a)
1965 {
1966         struct dso *p;
1967         size_t i;
1968         if (DL_FDPIC) for (p=head; p; p=p->next) {
1969                 i = count_syms(p);
1970                 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1971                         return p;
1972         }
1973         for (p=head; p; p=p->next) {
1974                 if (DL_FDPIC && p->loadmap) {
1975                         for (i=0; i<p->loadmap->nsegs; i++) {
1976                                 if (a-p->loadmap->segs[i].p_vaddr
1977                                     < p->loadmap->segs[i].p_memsz)
1978                                         return p;
1979                         }
1980                 } else {
1981                         Phdr *ph = p->phdr;
1982                         size_t phcnt = p->phnum;
1983                         size_t entsz = p->phentsize;
1984                         size_t base = (size_t)p->base;
1985                         for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
1986                                 if (ph->p_type != PT_LOAD) continue;
1987                                 if (a-base-ph->p_vaddr < ph->p_memsz)
1988                                         return p;
1989                         }
1990                         if (a-(size_t)p->map < p->map_len)
1991                                 return 0;
1992                 }
1993         }
1994         return 0;
1995 }
1996
1997 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1998 {
1999         size_t i;
2000         uint32_t h = 0, gh = 0, *ght;
2001         Sym *sym;
2002         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
2003                 if (p == RTLD_DEFAULT) {
2004                         p = head;
2005                 } else if (p == RTLD_NEXT) {
2006                         p = addr2dso((size_t)ra);
2007                         if (!p) p=head;
2008                         p = p->next;
2009                 }
2010                 struct symdef def = find_sym(p, s, 0);
2011                 if (!def.sym) goto failed;
2012                 if ((def.sym->st_info&0xf) == STT_TLS)
2013                         return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
2014                 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
2015                         return def.dso->funcdescs + (def.sym - def.dso->syms);
2016                 return laddr(def.dso, def.sym->st_value);
2017         }
2018         if (__dl_invalid_handle(p))
2019                 return 0;
2020         if ((ght = p->ghashtab)) {
2021                 gh = gnu_hash(s);
2022                 sym = gnu_lookup(gh, ght, p, s);
2023         } else {
2024                 h = sysv_hash(s);
2025                 sym = sysv_lookup(s, h, p);
2026         }
2027         if (sym && (sym->st_info&0xf) == STT_TLS)
2028                 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value-DTP_OFFSET});
2029         if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
2030                 return p->funcdescs + (sym - p->syms);
2031         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
2032                 return laddr(p, sym->st_value);
2033         for (i=0; p->deps[i]; i++) {
2034                 if ((ght = p->deps[i]->ghashtab)) {
2035                         if (!gh) gh = gnu_hash(s);
2036                         sym = gnu_lookup(gh, ght, p->deps[i], s);
2037                 } else {
2038                         if (!h) h = sysv_hash(s);
2039                         sym = sysv_lookup(s, h, p->deps[i]);
2040                 }
2041                 if (sym && (sym->st_info&0xf) == STT_TLS)
2042                         return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value-DTP_OFFSET});
2043                 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
2044                         return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
2045                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
2046                         return laddr(p->deps[i], sym->st_value);
2047         }
2048 failed:
2049         error("Symbol not found: %s", s);
2050         return 0;
2051 }
2052
2053 int dladdr(const void *addr_arg, Dl_info *info)
2054 {
2055         size_t addr = (size_t)addr_arg;
2056         struct dso *p;
2057         Sym *sym, *bestsym;
2058         uint32_t nsym;
2059         char *strings;
2060         size_t best = 0;
2061         size_t besterr = -1;
2062
2063         pthread_rwlock_rdlock(&lock);
2064         p = addr2dso(addr);
2065         pthread_rwlock_unlock(&lock);
2066
2067         if (!p) return 0;
2068
2069         sym = p->syms;
2070         strings = p->strings;
2071         nsym = count_syms(p);
2072
2073         if (DL_FDPIC) {
2074                 size_t idx = (addr-(size_t)p->funcdescs)
2075                         / sizeof(*p->funcdescs);
2076                 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2077                         best = (size_t)(p->funcdescs + idx);
2078                         bestsym = sym + idx;
2079                         besterr = 0;
2080                 }
2081         }
2082
2083         if (!best) for (; nsym; nsym--, sym++) {
2084                 if (sym->st_value
2085                  && (1<<(sym->st_info&0xf) & OK_TYPES)
2086                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
2087                         size_t symaddr = (size_t)laddr(p, sym->st_value);
2088                         if (symaddr > addr || symaddr <= best)
2089                                 continue;
2090                         best = symaddr;
2091                         bestsym = sym;
2092                         besterr = addr - symaddr;
2093                         if (addr == symaddr)
2094                                 break;
2095                 }
2096         }
2097
2098         if (bestsym && besterr > bestsym->st_size-1) {
2099                 best = 0;
2100                 bestsym = 0;
2101         }
2102
2103         info->dli_fname = p->name;
2104         info->dli_fbase = p->map;
2105
2106         if (!best) {
2107                 info->dli_sname = 0;
2108                 info->dli_saddr = 0;
2109                 return 1;
2110         }
2111
2112         if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2113                 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2114         info->dli_sname = strings + bestsym->st_name;
2115         info->dli_saddr = (void *)best;
2116
2117         return 1;
2118 }
2119
2120 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2121 {
2122         void *res;
2123         pthread_rwlock_rdlock(&lock);
2124         res = do_dlsym(p, s, ra);
2125         pthread_rwlock_unlock(&lock);
2126         return res;
2127 }
2128
2129 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2130 {
2131         struct dso *current;
2132         struct dl_phdr_info info;
2133         int ret = 0;
2134         for(current = head; current;) {
2135                 info.dlpi_addr      = (uintptr_t)current->base;
2136                 info.dlpi_name      = current->name;
2137                 info.dlpi_phdr      = current->phdr;
2138                 info.dlpi_phnum     = current->phnum;
2139                 info.dlpi_adds      = gencnt;
2140                 info.dlpi_subs      = 0;
2141                 info.dlpi_tls_modid = current->tls_id;
2142                 info.dlpi_tls_data  = current->tls.image;
2143
2144                 ret = (callback)(&info, sizeof (info), data);
2145
2146                 if (ret != 0) break;
2147
2148                 pthread_rwlock_rdlock(&lock);
2149                 current = current->next;
2150                 pthread_rwlock_unlock(&lock);
2151         }
2152         return ret;
2153 }
2154
2155 static void error(const char *fmt, ...)
2156 {
2157         va_list ap;
2158         va_start(ap, fmt);
2159         if (!runtime) {
2160                 vdprintf(2, fmt, ap);
2161                 dprintf(2, "\n");
2162                 ldso_fail = 1;
2163                 va_end(ap);
2164                 return;
2165         }
2166         __dl_vseterr(fmt, ap);
2167         va_end(ap);
2168 }