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