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