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