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

   1 #define _GNU_SOURCE
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6 #include <stdint.h>
   7 #include <elf.h>
   8 #include <sys/mman.h>
   9 #include <limits.h>
  10 #include <fcntl.h>
  11 #include <sys/stat.h>
  12 #include <errno.h>
  13 #include <link.h>
  14 #include <setjmp.h>
  15 #include <pthread.h>
  16 #include <ctype.h>
  17 #include <dlfcn.h>
  18 #include "pthread_impl.h"
  19 #include "libc.h"
  20
  21 static int errflag;
  22 static char errbuf[128];
  23
  24 #ifdef SHARED
  25
  26 #if ULONG_MAX == 0xffffffff
  27 typedef Elf32_Ehdr Ehdr;
  28 typedef Elf32_Phdr Phdr;
  29 typedef Elf32_Sym Sym;
  30 #define R_TYPE(x) ((x)&255)
  31 #define R_SYM(x) ((x)>>8)
  32 #else
  33 typedef Elf64_Ehdr Ehdr;
  34 typedef Elf64_Phdr Phdr;
  35 typedef Elf64_Sym Sym;
  36 #define R_TYPE(x) ((x)&0xffffffff)
  37 #define R_SYM(x) ((x)>>32)
  38 #endif
  39
  40 #define MAXP2(a,b) (-(-(a)&-(b)))
  41 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  42
  43 struct debug {
  44         int ver;
  45         void *head;
  46         void (*bp)(void);
  47         int state;
  48         void *base;
  49 };
  50
  51 struct dso {
  52         unsigned char *base;
  53         char *name;
  54         size_t *dynv;
  55         struct dso *next, *prev;
  56
  57         Phdr *phdr;
  58         int phnum;
  59         size_t phentsize;
  60         int refcnt;
  61         Sym *syms;
  62         uint32_t *hashtab;
  63         uint32_t *ghashtab;
  64         int16_t *versym;
  65         char *strings;
  66         unsigned char *map;
  67         size_t map_len;
  68         dev_t dev;
  69         ino_t ino;
  70         signed char global;
  71         char relocated;
  72         char constructed;
  73         char kernel_mapped;
  74         struct dso **deps, *needed_by;
  75         char *rpath_orig, *rpath;
  76         void *tls_image;
  77         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  78         size_t relro_start, relro_end;
  79         void **new_dtv;
  80         unsigned char *new_tls;
  81         int new_dtv_idx, new_tls_idx;
  82         struct dso *fini_next;
  83         char *shortname;
  84         char buf[];
  85 };
  86
  87 struct symdef {
  88         Sym *sym;
  89         struct dso *dso;
  90 };
  91
  92 enum {
  93         REL_ERR,
  94         REL_SYMBOLIC,
  95         REL_GOT,
  96         REL_PLT,
  97         REL_RELATIVE,
  98         REL_OFFSET,
  99         REL_OFFSET32,
 100         REL_COPY,
 101         REL_SYM_OR_REL,
 102         REL_TLS, /* everything past here is TLS */
 103         REL_DTPMOD,
 104         REL_DTPOFF,
 105         REL_TPOFF,
 106         REL_TPOFF_NEG,
 107 };
 108
 109 #include "reloc.h"
 110
 111 int __init_tp(void *);
 112 void __init_libc(char **, char *);
 113
 114 const char *__libc_get_version(void);
 115
 116 static struct dso *head, *tail, *ldso, *fini_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 size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
 127 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 128 static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
 129
 130 struct debug *_dl_debug_addr = &debug;
 131
 132 #define AUX_CNT 38
 133 #define DYN_CNT 34
 134
 135 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 136 {
 137         memset(a, 0, cnt*sizeof(size_t));
 138         for (; v[0]; v+=2) if (v[0]<cnt) {
 139                 a[0] |= 1ULL<<v[0];
 140                 a[v[0]] = v[1];
 141         }
 142 }
 143
 144 static int search_vec(size_t *v, size_t *r, size_t key)
 145 {
 146         for (; v[0]!=key; v+=2)
 147                 if (!v[0]) return 0;
 148         *r = v[1];
 149         return 1;
 150 }
 151
 152 static uint32_t sysv_hash(const char *s0)
 153 {
 154         const unsigned char *s = (void *)s0;
 155         uint_fast32_t h = 0;
 156         while (*s) {
 157                 h = 16*h + *s++;
 158                 h ^= h>>24 & 0xf0;
 159         }
 160         return h & 0xfffffff;
 161 }
 162
 163 static uint32_t gnu_hash(const char *s0)
 164 {
 165         const unsigned char *s = (void *)s0;
 166         uint_fast32_t h = 5381;
 167         for (; *s; s++)
 168                 h = h*33 + *s;
 169         return h;
 170 }
 171
 172 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 173 {
 174         size_t i;
 175         Sym *syms = dso->syms;
 176         uint32_t *hashtab = dso->hashtab;
 177         char *strings = dso->strings;
 178         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 179                 if ((!dso->versym || dso->versym[i] >= 0)
 180                     && (!strcmp(s, strings+syms[i].st_name)))
 181                         return syms+i;
 182         }
 183         return 0;
 184 }
 185
 186 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 187 {
 188         Sym *syms = dso->syms;
 189         char *strings = dso->strings;
 190         uint32_t *hashtab = dso->ghashtab;
 191         uint32_t nbuckets = hashtab[0];
 192         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 193         uint32_t h2;
 194         uint32_t *hashval;
 195         uint32_t i = buckets[h1 % nbuckets];
 196
 197         if (!i) return 0;
 198
 199         hashval = buckets + nbuckets + (i - hashtab[1]);
 200
 201         for (h1 |= 1; ; i++) {
 202                 h2 = *hashval++;
 203                 if ((!dso->versym || dso->versym[i] >= 0)
 204                     && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
 205                         return syms+i;
 206                 if (h2 & 1) break;
 207         }
 208
 209         return 0;
 210 }
 211
 212 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 213 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 214
 215 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 216 {
 217         uint32_t h = 0, gh = 0;
 218         struct symdef def = {0};
 219         for (; dso; dso=dso->next) {
 220                 Sym *sym;
 221                 if (!dso->global) continue;
 222                 if (dso->ghashtab) {
 223                         if (!gh) gh = gnu_hash(s);
 224                         sym = gnu_lookup(s, gh, dso);
 225                 } else {
 226                         if (!h) h = sysv_hash(s);
 227                         sym = sysv_lookup(s, h, dso);
 228                 }
 229                 if (!sym) continue;
 230                 if (!sym->st_shndx)
 231                         if (need_def || (sym->st_info&0xf) == STT_TLS)
 232                                 continue;
 233                 if (!sym->st_value)
 234                         if ((sym->st_info&0xf) != STT_TLS)
 235                                 continue;
 236                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 237                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 238
 239                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 240                 def.sym = sym;
 241                 def.dso = dso;
 242                 if (sym->st_info>>4 == STB_GLOBAL) break;
 243         }
 244         return def;
 245 }
 246
 247 #define NO_INLINE_ADDEND (1<<REL_COPY | 1<<REL_GOT | 1<<REL_PLT)
 248
 249 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 250 {
 251         unsigned char *base = dso->base;
 252         Sym *syms = dso->syms;
 253         char *strings = dso->strings;
 254         Sym *sym;
 255         const char *name;
 256         void *ctx;
 257         int astype, type;
 258         int sym_index;
 259         struct symdef def;
 260         size_t *reloc_addr;
 261         size_t sym_val;
 262         size_t tls_val;
 263         size_t addend;
 264
 265         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 266                 astype = R_TYPE(rel[1]);
 267                 if (!astype) continue;
 268                 type = remap_rel(astype);
 269                 if (!type) {
 270                         snprintf(errbuf, sizeof errbuf,
 271                                 "Error relocating %s: unsupported relocation type %d",
 272                                 dso->name, astype);
 273                         if (runtime) longjmp(*rtld_fail, 1);
 274                         dprintf(2, "%s\n", errbuf);
 275                         ldso_fail = 1;
 276                         continue;
 277                 }
 278                 sym_index = R_SYM(rel[1]);
 279                 reloc_addr = (void *)(base + rel[0]);
 280                 if (sym_index) {
 281                         sym = syms + sym_index;
 282                         name = strings + sym->st_name;
 283                         ctx = type==REL_COPY ? head->next : head;
 284                         def = find_sym(ctx, name, type==REL_PLT);
 285                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 286                             || sym->st_info>>4 != STB_WEAK)) {
 287                                 snprintf(errbuf, sizeof errbuf,
 288                                         "Error relocating %s: %s: symbol not found",
 289                                         dso->name, name);
 290                                 if (runtime) longjmp(*rtld_fail, 1);
 291                                 dprintf(2, "%s\n", errbuf);
 292                                 ldso_fail = 1;
 293                                 continue;
 294                         }
 295                 } else {
 296                         sym = 0;
 297                         def.sym = 0;
 298                         def.dso = dso;
 299                 }
 300
 301                 addend = stride>2 ? rel[2]
 302                         : (1<<type & NO_INLINE_ADDEND) ? 0
 303                         : *reloc_addr;
 304
 305                 sym_val = def.sym ? (size_t)def.dso->base+def.sym->st_value : 0;
 306                 tls_val = def.sym ? def.sym->st_value : 0;
 307
 308                 switch(type) {
 309                 case REL_OFFSET:
 310                         addend -= (size_t)reloc_addr;
 311                 case REL_SYMBOLIC:
 312                 case REL_GOT:
 313                 case REL_PLT:
 314                         *reloc_addr = sym_val + addend;
 315                         break;
 316                 case REL_RELATIVE:
 317                         *reloc_addr = (size_t)base + addend;
 318                         break;
 319                 case REL_SYM_OR_REL:
 320                         if (sym) *reloc_addr = sym_val + addend;
 321                         else *reloc_addr = (size_t)base + addend;
 322                         break;
 323                 case REL_COPY:
 324                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 325                         break;
 326                 case REL_OFFSET32:
 327                         *(uint32_t *)reloc_addr = sym_val + addend
 328                                 - (size_t)reloc_addr;
 329                         break;
 330                 case REL_DTPMOD:
 331                         *reloc_addr = def.dso->tls_id;
 332                         break;
 333                 case REL_DTPOFF:
 334                         *reloc_addr = tls_val + addend;
 335                         break;
 336 #ifdef TLS_ABOVE_TP
 337                 case REL_TPOFF:
 338                         *reloc_addr = tls_val + def.dso->tls_offset + TPOFF_K + addend;
 339                         break;
 340 #else
 341                 case REL_TPOFF:
 342                         *reloc_addr = tls_val - def.dso->tls_offset + addend;
 343                         break;
 344                 case REL_TPOFF_NEG:
 345                         *reloc_addr = def.dso->tls_offset - tls_val + addend;
 346                         break;
 347 #endif
 348                 }
 349         }
 350 }
 351
 352 /* A huge hack: to make up for the wastefulness of shared libraries
 353  * needing at least a page of dirty memory even if they have no global
 354  * data, we reclaim the gaps at the beginning and end of writable maps
 355  * and "donate" them to the heap by setting up minimal malloc
 356  * structures and then freeing them. */
 357
 358 static void reclaim(struct dso *dso, size_t start, size_t end)
 359 {
 360         size_t *a, *z;
 361         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 362         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 363         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 364         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 365         if (start>end || end-start < 4*sizeof(size_t)) return;
 366         a = (size_t *)(dso->base + start);
 367         z = (size_t *)(dso->base + end);
 368         a[-2] = 1;
 369         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 370         z[1] = 1;
 371         free(a);
 372 }
 373
 374 static void reclaim_gaps(struct dso *dso)
 375 {
 376         Phdr *ph = dso->phdr;
 377         size_t phcnt = dso->phnum;
 378
 379         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 380                 if (ph->p_type!=PT_LOAD) continue;
 381                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 382                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 383                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 384                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 385         }
 386 }
 387
 388 static void *map_library(int fd, struct dso *dso)
 389 {
 390         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 391         void *allocated_buf=0;
 392         size_t phsize;
 393         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 394         size_t this_min, this_max;
 395         off_t off_start;
 396         Ehdr *eh;
 397         Phdr *ph, *ph0;
 398         unsigned prot;
 399         unsigned char *map=MAP_FAILED, *base;
 400         size_t dyn=0;
 401         size_t tls_image=0;
 402         size_t i;
 403
 404         ssize_t l = read(fd, buf, sizeof buf);
 405         eh = buf;
 406         if (l<0) return 0;
 407         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 408                 goto noexec;
 409         phsize = eh->e_phentsize * eh->e_phnum;
 410         if (phsize > sizeof buf - sizeof *eh) {
 411                 allocated_buf = malloc(phsize);
 412                 if (!allocated_buf) return 0;
 413                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 414                 if (l < 0) goto error;
 415                 if (l != phsize) goto noexec;
 416                 ph = ph0 = allocated_buf;
 417         } else if (eh->e_phoff + phsize > l) {
 418                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 419                 if (l < 0) goto error;
 420                 if (l != phsize) goto noexec;
 421                 ph = ph0 = (void *)(buf + 1);
 422         } else {
 423                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 424         }
 425         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 426                 if (ph->p_type == PT_DYNAMIC) {
 427                         dyn = ph->p_vaddr;
 428                 } else if (ph->p_type == PT_TLS) {
 429                         tls_image = ph->p_vaddr;
 430                         dso->tls_align = ph->p_align;
 431                         dso->tls_len = ph->p_filesz;
 432                         dso->tls_size = ph->p_memsz;
 433                 } else if (ph->p_type == PT_GNU_RELRO) {
 434                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 435                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 436                 }
 437                 if (ph->p_type != PT_LOAD) continue;
 438                 if (ph->p_vaddr < addr_min) {
 439                         addr_min = ph->p_vaddr;
 440                         off_start = ph->p_offset;
 441                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 442                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 443                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 444                 }
 445                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 446                         addr_max = ph->p_vaddr+ph->p_memsz;
 447                 }
 448         }
 449         if (!dyn) goto noexec;
 450         addr_max += PAGE_SIZE-1;
 451         addr_max &= -PAGE_SIZE;
 452         addr_min &= -PAGE_SIZE;
 453         off_start &= -PAGE_SIZE;
 454         map_len = addr_max - addr_min + off_start;
 455         /* The first time, we map too much, possibly even more than
 456          * the length of the file. This is okay because we will not
 457          * use the invalid part; we just need to reserve the right
 458          * amount of virtual address space to map over later. */
 459         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 460         if (map==MAP_FAILED) goto error;
 461         /* If the loaded file is not relocatable and the requested address is
 462          * not available, then the load operation must fail. */
 463         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 464                 errno = EBUSY;
 465                 goto error;
 466         }
 467         base = map - addr_min;
 468         dso->phdr = 0;
 469         dso->phnum = 0;
 470         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 471                 if (ph->p_type != PT_LOAD) continue;
 472                 /* Check if the programs headers are in this load segment, and
 473                  * if so, record the address for use by dl_iterate_phdr. */
 474                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 475                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 476                         dso->phdr = (void *)(base + ph->p_vaddr
 477                                 + (eh->e_phoff-ph->p_offset));
 478                         dso->phnum = eh->e_phnum;
 479                         dso->phentsize = eh->e_phentsize;
 480                 }
 481                 /* Reuse the existing mapping for the lowest-address LOAD */
 482                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 483                 this_min = ph->p_vaddr & -PAGE_SIZE;
 484                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 485                 off_start = ph->p_offset & -PAGE_SIZE;
 486                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 487                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 488                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 489                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 490                         goto error;
 491                 if (ph->p_memsz > ph->p_filesz) {
 492                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 493                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 494                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 495                         if (pgbrk-(size_t)base < this_max && mmap((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED)
 496                                 goto error;
 497                 }
 498         }
 499         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 500                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 501                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 502                                 goto error;
 503                         break;
 504                 }
 505         dso->map = map;
 506         dso->map_len = map_len;
 507         dso->base = base;
 508         dso->dynv = (void *)(base+dyn);
 509         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 510         if (!runtime) reclaim_gaps(dso);
 511         free(allocated_buf);
 512         return map;
 513 noexec:
 514         errno = ENOEXEC;
 515 error:
 516         if (map!=MAP_FAILED) munmap(map, map_len);
 517         free(allocated_buf);
 518         return 0;
 519 }
 520
 521 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 522 {
 523         size_t l;
 524         int fd;
 525         for (;;) {
 526                 s += strspn(s, ":\n");
 527                 l = strcspn(s, ":\n");
 528                 if (l-1 >= INT_MAX) return -1;
 529                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
 530                         continue;
 531                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 532                 s += l;
 533         }
 534 }
 535
 536 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 537 {
 538         size_t n, l;
 539         const char *s, *t, *origin;
 540         char *d;
 541         if (p->rpath) return 0;
 542         if (!p->rpath_orig) return -1;
 543         if (!strchr(p->rpath_orig, '$')) {
 544                 p->rpath = p->rpath_orig;
 545                 return 0;
 546         }
 547         n = 0;
 548         s = p->rpath_orig;
 549         while ((t=strchr(s, '$'))) {
 550                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 551                         return -1;
 552                 s = t+1;
 553                 n++;
 554         }
 555         if (n > SSIZE_MAX/PATH_MAX) return -1;
 556
 557         if (p->kernel_mapped) {
 558                 /* $ORIGIN searches cannot be performed for the main program
 559                  * when it is suid/sgid/AT_SECURE. This is because the
 560                  * pathname is under the control of the caller of execve.
 561                  * For libraries, however, $ORIGIN can be processed safely
 562                  * since the library's pathname came from a trusted source
 563                  * (either system paths or a call to dlopen). */
 564                 if (libc.secure)
 565                         return -1;
 566                 l = readlink("/proc/self/exe", buf, buf_size);
 567                 if (l >= buf_size)
 568                         return -1;
 569                 buf[l] = 0;
 570                 origin = buf;
 571         } else {
 572                 origin = p->name;
 573         }
 574         t = strrchr(origin, '/');
 575         l = t ? t-origin : 0;
 576         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 577         if (!p->rpath) return -1;
 578
 579         d = p->rpath;
 580         s = p->rpath_orig;
 581         while ((t=strchr(s, '$'))) {
 582                 memcpy(d, s, t-s);
 583                 d += t-s;
 584                 memcpy(d, origin, l);
 585                 d += l;
 586                 /* It was determined previously that the '$' is followed
 587                  * either by "ORIGIN" or "{ORIGIN}". */
 588                 s = t + 7 + 2*(t[1]=='{');
 589         }
 590         strcpy(d, s);
 591         return 0;
 592 }
 593
 594 static void decode_dyn(struct dso *p)
 595 {
 596         size_t dyn[DYN_CNT] = {0};
 597         decode_vec(p->dynv, dyn, DYN_CNT);
 598         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 599         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 600         if (dyn[0]&(1<<DT_HASH))
 601                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 602         if (dyn[0]&(1<<DT_RPATH))
 603                 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
 604         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 605                 p->ghashtab = (void *)(p->base + *dyn);
 606         if (search_vec(p->dynv, dyn, DT_VERSYM))
 607                 p->versym = (void *)(p->base + *dyn);
 608 }
 609
 610 static struct dso *load_library(const char *name, struct dso *needed_by)
 611 {
 612         char buf[2*NAME_MAX+2];
 613         const char *pathname;
 614         unsigned char *map;
 615         struct dso *p, temp_dso = {0};
 616         int fd;
 617         struct stat st;
 618         size_t alloc_size;
 619         int n_th = 0;
 620         int is_self = 0;
 621
 622         /* Catch and block attempts to reload the implementation itself */
 623         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 624                 static const char *rp, reserved[] =
 625                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 626                 char *z = strchr(name, '.');
 627                 if (z) {
 628                         size_t l = z-name;
 629                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 630                         if (*rp) {
 631                                 if (ldd_mode) {
 632                                         /* Track which names have been resolved
 633                                          * and only report each one once. */
 634                                         static unsigned reported;
 635                                         unsigned mask = 1U<<(rp-reserved);
 636                                         if (!(reported & mask)) {
 637                                                 reported |= mask;
 638                                                 dprintf(1, "\t%s => %s (%p)\n",
 639                                                         name, ldso->name,
 640                                                         ldso->base);
 641                                         }
 642                                 }
 643                                 is_self = 1;
 644                         }
 645                 }
 646         }
 647         if (!strcmp(name, ldso->name)) is_self = 1;
 648         if (is_self) {
 649                 if (!ldso->prev) {
 650                         tail->next = ldso;
 651                         ldso->prev = tail;
 652                         tail = ldso->next ? ldso->next : ldso;
 653                 }
 654                 return ldso;
 655         }
 656         if (strchr(name, '/')) {
 657                 pathname = name;
 658                 fd = open(name, O_RDONLY|O_CLOEXEC);
 659         } else {
 660                 /* Search for the name to see if it's already loaded */
 661                 for (p=head->next; p; p=p->next) {
 662                         if (p->shortname && !strcmp(p->shortname, name)) {
 663                                 p->refcnt++;
 664                                 return p;
 665                         }
 666                 }
 667                 if (strlen(name) > NAME_MAX) return 0;
 668                 fd = -1;
 669                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 670                 for (p=needed_by; fd < 0 && p; p=p->needed_by)
 671                         if (!fixup_rpath(p, buf, sizeof buf))
 672                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 673                 if (fd < 0) {
 674                         if (!sys_path) {
 675                                 char *prefix = 0;
 676                                 size_t prefix_len;
 677                                 if (ldso->name[0]=='/') {
 678                                         char *s, *t, *z;
 679                                         for (s=t=z=ldso->name; *s; s++)
 680                                                 if (*s=='/') z=t, t=s;
 681                                         prefix_len = z-ldso->name;
 682                                         if (prefix_len < PATH_MAX)
 683                                                 prefix = ldso->name;
 684                                 }
 685                                 if (!prefix) {
 686                                         prefix = "";
 687                                         prefix_len = 0;
 688                                 }
 689                                 char etc_ldso_path[prefix_len + 1
 690                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 691                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 692                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 693                                         (int)prefix_len, prefix);
 694                                 FILE *f = fopen(etc_ldso_path, "rbe");
 695                                 if (f) {
 696                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 697                                                 free(sys_path);
 698                                                 sys_path = "";
 699                                         }
 700                                         fclose(f);
 701                                 } else if (errno != ENOENT) {
 702                                         sys_path = "";
 703                                 }
 704                         }
 705                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 706                         fd = path_open(name, sys_path, buf, sizeof buf);
 707                 }
 708                 pathname = buf;
 709         }
 710         if (fd < 0) return 0;
 711         if (fstat(fd, &st) < 0) {
 712                 close(fd);
 713                 return 0;
 714         }
 715         for (p=head->next; p; p=p->next) {
 716                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 717                         /* If this library was previously loaded with a
 718                          * pathname but a search found the same inode,
 719                          * setup its shortname so it can be found by name. */
 720                         if (!p->shortname && pathname != name)
 721                                 p->shortname = strrchr(p->name, '/')+1;
 722                         close(fd);
 723                         p->refcnt++;
 724                         return p;
 725                 }
 726         }
 727         map = noload ? 0 : map_library(fd, &temp_dso);
 728         close(fd);
 729         if (!map) return 0;
 730
 731         /* Allocate storage for the new DSO. When there is TLS, this
 732          * storage must include a reservation for all pre-existing
 733          * threads to obtain copies of both the new TLS, and an
 734          * extended DTV capable of storing an additional slot for
 735          * the newly-loaded DSO. */
 736         alloc_size = sizeof *p + strlen(pathname) + 1;
 737         if (runtime && temp_dso.tls_image) {
 738                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 739                         + sizeof(void *) * (tls_cnt+3);
 740                 n_th = libc.threads_minus_1 + 1;
 741                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 742                 else alloc_size += n_th * per_th;
 743         }
 744         p = calloc(1, alloc_size);
 745         if (!p) {
 746                 munmap(map, temp_dso.map_len);
 747                 return 0;
 748         }
 749         memcpy(p, &temp_dso, sizeof temp_dso);
 750         decode_dyn(p);
 751         p->dev = st.st_dev;
 752         p->ino = st.st_ino;
 753         p->refcnt = 1;
 754         p->needed_by = needed_by;
 755         p->name = p->buf;
 756         strcpy(p->name, pathname);
 757         /* Add a shortname only if name arg was not an explicit pathname. */
 758         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 759         if (p->tls_image) {
 760                 if (runtime && !libc.has_thread_pointer) {
 761                         munmap(map, p->map_len);
 762                         free(p);
 763                         errno = ENOSYS;
 764                         return 0;
 765                 }
 766                 p->tls_id = ++tls_cnt;
 767                 tls_align = MAXP2(tls_align, p->tls_align);
 768 #ifdef TLS_ABOVE_TP
 769                 p->tls_offset = tls_offset + ( (tls_align-1) &
 770                         -(tls_offset + (uintptr_t)p->tls_image) );
 771                 tls_offset += p->tls_size;
 772 #else
 773                 tls_offset += p->tls_size + p->tls_align - 1;
 774                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 775                         & (p->tls_align-1);
 776                 p->tls_offset = tls_offset;
 777 #endif
 778                 p->new_dtv = (void *)(-sizeof(size_t) &
 779                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 780                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 781         }
 782
 783         tail->next = p;
 784         p->prev = tail;
 785         tail = p;
 786
 787         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 788
 789         return p;
 790 }
 791
 792 static void load_deps(struct dso *p)
 793 {
 794         size_t i, ndeps=0;
 795         struct dso ***deps = &p->deps, **tmp, *dep;
 796         for (; p; p=p->next) {
 797                 for (i=0; p->dynv[i]; i+=2) {
 798                         if (p->dynv[i] != DT_NEEDED) continue;
 799                         dep = load_library(p->strings + p->dynv[i+1], p);
 800                         if (!dep) {
 801                                 snprintf(errbuf, sizeof errbuf,
 802                                         "Error loading shared library %s: %m (needed by %s)",
 803                                         p->strings + p->dynv[i+1], p->name);
 804                                 if (runtime) longjmp(*rtld_fail, 1);
 805                                 dprintf(2, "%s\n", errbuf);
 806                                 ldso_fail = 1;
 807                                 continue;
 808                         }
 809                         if (runtime) {
 810                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 811                                 if (!tmp) longjmp(*rtld_fail, 1);
 812                                 tmp[ndeps++] = dep;
 813                                 tmp[ndeps] = 0;
 814                                 *deps = tmp;
 815                         }
 816                 }
 817         }
 818 }
 819
 820 static void load_preload(char *s)
 821 {
 822         int tmp;
 823         char *z;
 824         for (z=s; *z; s=z) {
 825                 for (   ; *s && isspace(*s); s++);
 826                 for (z=s; *z && !isspace(*z); z++);
 827                 tmp = *z;
 828                 *z = 0;
 829                 load_library(s, 0);
 830                 *z = tmp;
 831         }
 832 }
 833
 834 static void make_global(struct dso *p)
 835 {
 836         for (; p; p=p->next) p->global = 1;
 837 }
 838
 839 static void reloc_all(struct dso *p)
 840 {
 841         size_t dyn[DYN_CNT] = {0};
 842         for (; p; p=p->next) {
 843                 if (p->relocated) continue;
 844                 decode_vec(p->dynv, dyn, DYN_CNT);
 845 #ifdef NEED_ARCH_RELOCS
 846                 do_arch_relocs(p, head);
 847 #endif
 848                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 849                         2+(dyn[DT_PLTREL]==DT_RELA));
 850                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 851                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 852
 853                 if (p->relro_start != p->relro_end &&
 854                     mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) {
 855                         snprintf(errbuf, sizeof errbuf,
 856                                 "Error relocating %s: RELRO protection failed: %m",
 857                                 p->name);
 858                         if (runtime) longjmp(*rtld_fail, 1);
 859                         dprintf(2, "%s\n", errbuf);
 860                         ldso_fail = 1;
 861                 }
 862
 863                 p->relocated = 1;
 864         }
 865 }
 866
 867 static void kernel_mapped_dso(struct dso *p)
 868 {
 869         size_t min_addr = -1, max_addr = 0, cnt;
 870         Phdr *ph = p->phdr;
 871         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
 872                 if (ph->p_type == PT_DYNAMIC) {
 873                         p->dynv = (void *)(p->base + ph->p_vaddr);
 874                 } else if (ph->p_type == PT_GNU_RELRO) {
 875                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
 876                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 877                 }
 878                 if (ph->p_type != PT_LOAD) continue;
 879                 if (ph->p_vaddr < min_addr)
 880                         min_addr = ph->p_vaddr;
 881                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 882                         max_addr = ph->p_vaddr+ph->p_memsz;
 883         }
 884         min_addr &= -PAGE_SIZE;
 885         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 886         p->map = p->base + min_addr;
 887         p->map_len = max_addr - min_addr;
 888         p->kernel_mapped = 1;
 889 }
 890
 891 static void do_fini()
 892 {
 893         struct dso *p;
 894         size_t dyn[DYN_CNT] = {0};
 895         for (p=fini_head; p; p=p->fini_next) {
 896                 if (!p->constructed) continue;
 897                 decode_vec(p->dynv, dyn, DYN_CNT);
 898                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
 899                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
 900                         size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
 901                         while (n--) ((void (*)(void))*--fn)();
 902                 }
 903 #ifndef NO_LEGACY_INITFINI
 904                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
 905                         ((void (*)(void))(p->base + dyn[DT_FINI]))();
 906 #endif
 907         }
 908 }
 909
 910 static void do_init_fini(struct dso *p)
 911 {
 912         size_t dyn[DYN_CNT] = {0};
 913         int need_locking = libc.threads_minus_1;
 914         /* Allow recursive calls that arise when a library calls
 915          * dlopen from one of its constructors, but block any
 916          * other threads until all ctors have finished. */
 917         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 918         for (; p; p=p->prev) {
 919                 if (p->constructed) continue;
 920                 p->constructed = 1;
 921                 decode_vec(p->dynv, dyn, DYN_CNT);
 922                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
 923                         p->fini_next = fini_head;
 924                         fini_head = p;
 925                 }
 926 #ifndef NO_LEGACY_INITFINI
 927                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
 928                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 929 #endif
 930                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
 931                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
 932                         size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
 933                         while (n--) ((void (*)(void))*fn++)();
 934                 }
 935                 if (!need_locking && libc.threads_minus_1) {
 936                         need_locking = 1;
 937                         pthread_mutex_lock(&init_fini_lock);
 938                 }
 939         }
 940         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 941 }
 942
 943 void _dl_debug_state(void)
 944 {
 945 }
 946
 947 void __reset_tls()
 948 {
 949         pthread_t self = __pthread_self();
 950         struct dso *p;
 951         for (p=head; p; p=p->next) {
 952                 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
 953                 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
 954                 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
 955                         p->tls_size - p->tls_len);
 956                 if (p->tls_id == (size_t)self->dtv[0]) break;
 957         }
 958 }
 959
 960 void *__copy_tls(unsigned char *mem)
 961 {
 962         pthread_t td;
 963         struct dso *p;
 964
 965         void **dtv = (void *)mem;
 966         dtv[0] = (void *)tls_cnt;
 967         if (!tls_cnt) {
 968                 td = (void *)(dtv+1);
 969                 td->dtv = dtv;
 970                 return td;
 971         }
 972
 973 #ifdef TLS_ABOVE_TP
 974         mem += sizeof(void *) * (tls_cnt+1);
 975         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
 976         td = (pthread_t)mem;
 977         mem += sizeof(struct pthread);
 978
 979         for (p=head; p; p=p->next) {
 980                 if (!p->tls_id) continue;
 981                 dtv[p->tls_id] = mem + p->tls_offset;
 982                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 983         }
 984 #else
 985         mem += libc.tls_size - sizeof(struct pthread);
 986         mem -= (uintptr_t)mem & (tls_align-1);
 987         td = (pthread_t)mem;
 988
 989         for (p=head; p; p=p->next) {
 990                 if (!p->tls_id) continue;
 991                 dtv[p->tls_id] = mem - p->tls_offset;
 992                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 993         }
 994 #endif
 995         td->dtv = dtv;
 996         return td;
 997 }
 998
 999 void *__tls_get_addr(size_t *v)
1000 {
1001         pthread_t self = __pthread_self();
1002         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
1003                 return (char *)self->dtv[v[0]]+v[1];
1004
1005         /* Block signals to make accessing new TLS async-signal-safe */
1006         sigset_t set;
1007         pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
1008         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
1009                 pthread_sigmask(SIG_SETMASK, &set, 0);
1010                 return (char *)self->dtv[v[0]]+v[1];
1011         }
1012
1013         /* This is safe without any locks held because, if the caller
1014          * is able to request the Nth entry of the DTV, the DSO list
1015          * must be valid at least that far out and it was synchronized
1016          * at program startup or by an already-completed call to dlopen. */
1017         struct dso *p;
1018         for (p=head; p->tls_id != v[0]; p=p->next);
1019
1020         /* Get new DTV space from new DSO if needed */
1021         if (v[0] > (size_t)self->dtv[0]) {
1022                 void **newdtv = p->new_dtv +
1023                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1024                 memcpy(newdtv, self->dtv,
1025                         ((size_t)self->dtv[0]+1) * sizeof(void *));
1026                 newdtv[0] = (void *)v[0];
1027                 self->dtv = newdtv;
1028         }
1029
1030         /* Get new TLS memory from new DSO */
1031         unsigned char *mem = p->new_tls +
1032                 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
1033         mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
1034         self->dtv[v[0]] = mem;
1035         memcpy(mem, p->tls_image, p->tls_len);
1036         pthread_sigmask(SIG_SETMASK, &set, 0);
1037         return mem + v[1];
1038 }
1039
1040 static void update_tls_size()
1041 {
1042         libc.tls_size = ALIGN(
1043                 (1+tls_cnt) * sizeof(void *) +
1044                 tls_offset +
1045                 sizeof(struct pthread) +
1046                 tls_align * 2,
1047         tls_align);
1048 }
1049
1050 void *__dynlink(int argc, char **argv)
1051 {
1052         size_t aux[AUX_CNT] = {0};
1053         size_t i;
1054         Phdr *phdr;
1055         Ehdr *ehdr;
1056         static struct dso builtin_dsos[3];
1057         struct dso *const app = builtin_dsos+0;
1058         struct dso *const lib = builtin_dsos+1;
1059         struct dso *const vdso = builtin_dsos+2;
1060         char *env_preload=0;
1061         size_t vdso_base;
1062         size_t *auxv;
1063         char **envp = argv+argc+1;
1064         void *initial_tls;
1065
1066         /* Find aux vector just past environ[] */
1067         for (i=argc+1; argv[i]; i++)
1068                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
1069                         env_path = argv[i]+16;
1070                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
1071                         env_preload = argv[i]+11;
1072         auxv = (void *)(argv+i+1);
1073
1074         decode_vec(auxv, aux, AUX_CNT);
1075
1076         /* Only trust user/env if kernel says we're not suid/sgid */
1077         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1078           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
1079                 env_path = 0;
1080                 env_preload = 0;
1081                 libc.secure = 1;
1082         }
1083         libc.page_size = aux[AT_PAGESZ];
1084
1085         /* If the dynamic linker was invoked as a program itself, AT_BASE
1086          * will not be set. In that case, we assume the base address is
1087          * the start of the page containing the PHDRs; I don't know any
1088          * better approach... */
1089         if (!aux[AT_BASE]) {
1090                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
1091                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
1092         }
1093
1094         /* The dynamic linker load address is passed by the kernel
1095          * in the AUX vector, so this is easy. */
1096         lib->base = (void *)aux[AT_BASE];
1097         lib->name = lib->shortname = "libc.so";
1098         lib->global = 1;
1099         ehdr = (void *)lib->base;
1100         lib->phnum = ehdr->e_phnum;
1101         lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1102         lib->phentsize = ehdr->e_phentsize;
1103         kernel_mapped_dso(lib);
1104         decode_dyn(lib);
1105
1106         if (aux[AT_PHDR]) {
1107                 size_t interp_off = 0;
1108                 size_t tls_image = 0;
1109                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1110                 app->phdr = phdr = (void *)aux[AT_PHDR];
1111                 app->phnum = aux[AT_PHNUM];
1112                 app->phentsize = aux[AT_PHENT];
1113                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1114                         if (phdr->p_type == PT_PHDR)
1115                                 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1116                         else if (phdr->p_type == PT_INTERP)
1117                                 interp_off = (size_t)phdr->p_vaddr;
1118                         else if (phdr->p_type == PT_TLS) {
1119                                 tls_image = phdr->p_vaddr;
1120                                 app->tls_len = phdr->p_filesz;
1121                                 app->tls_size = phdr->p_memsz;
1122                                 app->tls_align = phdr->p_align;
1123                         }
1124                 }
1125                 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1126                 if (interp_off) lib->name = (char *)app->base + interp_off;
1127                 if ((aux[0] & (1UL<<AT_EXECFN))
1128                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1129                         app->name = (char *)aux[AT_EXECFN];
1130                 else
1131                         app->name = argv[0];
1132                 kernel_mapped_dso(app);
1133         } else {
1134                 int fd;
1135                 char *ldname = argv[0];
1136                 size_t l = strlen(ldname);
1137                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1138                 *argv++ = (void *)-1;
1139                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1140                         char *opt = argv[0]+2;
1141                         *argv++ = (void *)-1;
1142                         if (!*opt) {
1143                                 break;
1144                         } else if (!memcmp(opt, "list", 5)) {
1145                                 ldd_mode = 1;
1146                         } else if (!memcmp(opt, "library-path", 12)) {
1147                                 if (opt[12]=='=') env_path = opt+13;
1148                                 else if (opt[12]) *argv = 0;
1149                                 else if (*argv) env_path = *argv++;
1150                         } else if (!memcmp(opt, "preload", 7)) {
1151                                 if (opt[7]=='=') env_preload = opt+8;
1152                                 else if (opt[7]) *argv = 0;
1153                                 else if (*argv) env_preload = *argv++;
1154                         } else {
1155                                 argv[0] = 0;
1156                         }
1157                         argv[-1] = (void *)-1;
1158                 }
1159                 if (!argv[0]) {
1160                         dprintf(2, "musl libc\n"
1161                                 "Version %s\n"
1162                                 "Dynamic Program Loader\n"
1163                                 "Usage: %s [options] [--] pathname%s\n",
1164                                 __libc_get_version(), ldname,
1165                                 ldd_mode ? "" : " [args]");
1166                         _exit(1);
1167                 }
1168                 fd = open(argv[0], O_RDONLY);
1169                 if (fd < 0) {
1170                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1171                         _exit(1);
1172                 }
1173                 runtime = 1;
1174                 ehdr = (void *)map_library(fd, app);
1175                 if (!ehdr) {
1176                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1177                         _exit(1);
1178                 }
1179                 runtime = 0;
1180                 close(fd);
1181                 lib->name = ldname;
1182                 app->name = argv[0];
1183                 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1184                 /* Find the name that would have been used for the dynamic
1185                  * linker had ldd not taken its place. */
1186                 if (ldd_mode) {
1187                         for (i=0; i<app->phnum; i++) {
1188                                 if (app->phdr[i].p_type == PT_INTERP)
1189                                         lib->name = (void *)(app->base
1190                                                 + app->phdr[i].p_vaddr);
1191                         }
1192                         dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1193                 }
1194         }
1195         if (app->tls_size) {
1196                 app->tls_id = tls_cnt = 1;
1197 #ifdef TLS_ABOVE_TP
1198                 app->tls_offset = 0;
1199                 tls_offset = app->tls_size
1200                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1201                         & (app->tls_align-1) );
1202 #else
1203                 tls_offset = app->tls_offset = app->tls_size
1204                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1205                         & (app->tls_align-1) );
1206 #endif
1207                 tls_align = MAXP2(tls_align, app->tls_align);
1208         }
1209         app->global = 1;
1210         decode_dyn(app);
1211
1212         /* Attach to vdso, if provided by the kernel */
1213         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1214                 ehdr = (void *)vdso_base;
1215                 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1216                 vdso->phnum = ehdr->e_phnum;
1217                 vdso->phentsize = ehdr->e_phentsize;
1218                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1219                         if (phdr->p_type == PT_DYNAMIC)
1220                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1221                         if (phdr->p_type == PT_LOAD)
1222                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1223                 }
1224                 vdso->name = "";
1225                 vdso->shortname = "linux-gate.so.1";
1226                 vdso->global = 1;
1227                 decode_dyn(vdso);
1228                 vdso->prev = lib;
1229                 lib->next = vdso;
1230         }
1231
1232         /* Initial dso chain consists only of the app. We temporarily
1233          * append the dynamic linker/libc so we can relocate it, then
1234          * restore the initial chain in preparation for loading third
1235          * party libraries (preload/needed). */
1236         head = tail = app;
1237         ldso = lib;
1238         app->next = lib;
1239         reloc_all(lib);
1240         app->next = 0;
1241
1242         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1243
1244         /* Donate unused parts of app and library mapping to malloc */
1245         reclaim_gaps(app);
1246         reclaim_gaps(lib);
1247
1248         /* Load preload/needed libraries, add their symbols to the global
1249          * namespace, and perform all remaining relocations. The main
1250          * program must be relocated LAST since it may contain copy
1251          * relocations which depend on libraries' relocations. */
1252         if (env_preload) load_preload(env_preload);
1253         load_deps(app);
1254         make_global(app);
1255
1256 #ifndef DYNAMIC_IS_RO
1257         for (i=0; app->dynv[i]; i+=2)
1258                 if (app->dynv[i]==DT_DEBUG)
1259                         app->dynv[i+1] = (size_t)&debug;
1260 #endif
1261
1262         reloc_all(app->next);
1263         reloc_all(app);
1264
1265         update_tls_size();
1266         if (libc.tls_size > sizeof builtin_tls) {
1267                 initial_tls = calloc(libc.tls_size, 1);
1268                 if (!initial_tls) {
1269                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1270                                 argv[0], libc.tls_size);
1271                         _exit(127);
1272                 }
1273         } else {
1274                 initial_tls = builtin_tls;
1275         }
1276         if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
1277                 dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
1278                 _exit(127);
1279         }
1280
1281         if (ldso_fail) _exit(127);
1282         if (ldd_mode) _exit(0);
1283
1284         /* Switch to runtime mode: any further failures in the dynamic
1285          * linker are a reportable failure rather than a fatal startup
1286          * error. If the dynamic loader (dlopen) will not be used, free
1287          * all memory used by the dynamic linker. */
1288         runtime = 1;
1289
1290         debug.ver = 1;
1291         debug.bp = _dl_debug_state;
1292         debug.head = head;
1293         debug.base = lib->base;
1294         debug.state = 0;
1295         _dl_debug_state();
1296
1297         __init_libc(envp, argv[0]);
1298         atexit(do_fini);
1299         errno = 0;
1300         do_init_fini(tail);
1301
1302         return (void *)aux[AT_ENTRY];
1303 }
1304
1305 void *dlopen(const char *file, int mode)
1306 {
1307         struct dso *volatile p, *orig_tail, *next;
1308         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1309         size_t i;
1310         int cs;
1311         jmp_buf jb;
1312
1313         if (!file) return head;
1314
1315         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1316         pthread_rwlock_wrlock(&lock);
1317         __inhibit_ptc();
1318
1319         p = 0;
1320         orig_tls_cnt = tls_cnt;
1321         orig_tls_offset = tls_offset;
1322         orig_tls_align = tls_align;
1323         orig_tail = tail;
1324         noload = mode & RTLD_NOLOAD;
1325
1326         rtld_fail = &jb;
1327         if (setjmp(*rtld_fail)) {
1328                 /* Clean up anything new that was (partially) loaded */
1329                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1330                         if (p->deps[i]->global < 0)
1331                                 p->deps[i]->global = 0;
1332                 for (p=orig_tail->next; p; p=next) {
1333                         next = p->next;
1334                         munmap(p->map, p->map_len);
1335                         free(p->deps);
1336                         free(p);
1337                 }
1338                 tls_cnt = orig_tls_cnt;
1339                 tls_offset = orig_tls_offset;
1340                 tls_align = orig_tls_align;
1341                 tail = orig_tail;
1342                 tail->next = 0;
1343                 p = 0;
1344                 errflag = 1;
1345                 goto end;
1346         } else p = load_library(file, head);
1347
1348         if (!p) {
1349                 snprintf(errbuf, sizeof errbuf, noload ?
1350                         "Library %s is not already loaded" :
1351                         "Error loading shared library %s: %m",
1352                         file);
1353                 errflag = 1;
1354                 goto end;
1355         }
1356
1357         /* First load handling */
1358         if (!p->deps) {
1359                 load_deps(p);
1360                 if (p->deps) for (i=0; p->deps[i]; i++)
1361                         if (!p->deps[i]->global)
1362                                 p->deps[i]->global = -1;
1363                 if (!p->global) p->global = -1;
1364                 reloc_all(p);
1365                 if (p->deps) for (i=0; p->deps[i]; i++)
1366                         if (p->deps[i]->global < 0)
1367                                 p->deps[i]->global = 0;
1368                 if (p->global < 0) p->global = 0;
1369         }
1370
1371         if (mode & RTLD_GLOBAL) {
1372                 if (p->deps) for (i=0; p->deps[i]; i++)
1373                         p->deps[i]->global = 1;
1374                 p->global = 1;
1375         }
1376
1377         update_tls_size();
1378         _dl_debug_state();
1379         orig_tail = tail;
1380 end:
1381         __release_ptc();
1382         if (p) gencnt++;
1383         pthread_rwlock_unlock(&lock);
1384         if (p) do_init_fini(orig_tail);
1385         pthread_setcancelstate(cs, 0);
1386         return p;
1387 }
1388
1389 static int invalid_dso_handle(void *h)
1390 {
1391         struct dso *p;
1392         for (p=head; p; p=p->next) if (h==p) return 0;
1393         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1394         errflag = 1;
1395         return 1;
1396 }
1397
1398 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1399 {
1400         size_t i;
1401         uint32_t h = 0, gh = 0;
1402         Sym *sym;
1403         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1404                 if (p == RTLD_DEFAULT) {
1405                         p = head;
1406                 } else if (p == RTLD_NEXT) {
1407                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1408                         if (!p) p=head;
1409                         p = p->next;
1410                 }
1411                 struct symdef def = find_sym(p, s, 0);
1412                 if (!def.sym) goto failed;
1413                 if ((def.sym->st_info&0xf) == STT_TLS)
1414                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1415                 return def.dso->base + def.sym->st_value;
1416         }
1417         if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1418                 return 0;
1419         if (p->ghashtab) {
1420                 gh = gnu_hash(s);
1421                 sym = gnu_lookup(s, gh, p);
1422         } else {
1423                 h = sysv_hash(s);
1424                 sym = sysv_lookup(s, h, p);
1425         }
1426         if (sym && (sym->st_info&0xf) == STT_TLS)
1427                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1428         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1429                 return p->base + sym->st_value;
1430         if (p->deps) for (i=0; p->deps[i]; i++) {
1431                 if (p->deps[i]->ghashtab) {
1432                         if (!gh) gh = gnu_hash(s);
1433                         sym = gnu_lookup(s, gh, p->deps[i]);
1434                 } else {
1435                         if (!h) h = sysv_hash(s);
1436                         sym = sysv_lookup(s, h, p->deps[i]);
1437                 }
1438                 if (sym && (sym->st_info&0xf) == STT_TLS)
1439                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1440                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1441                         return p->deps[i]->base + sym->st_value;
1442         }
1443 failed:
1444         errflag = 1;
1445         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1446         return 0;
1447 }
1448
1449 int __dladdr(const void *addr, Dl_info *info)
1450 {
1451         struct dso *p;
1452         Sym *sym;
1453         uint32_t nsym;
1454         char *strings;
1455         size_t i;
1456         void *best = 0;
1457         char *bestname;
1458
1459         pthread_rwlock_rdlock(&lock);
1460         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1461         pthread_rwlock_unlock(&lock);
1462
1463         if (!p) return 0;
1464
1465         sym = p->syms;
1466         strings = p->strings;
1467         if (p->hashtab) {
1468                 nsym = p->hashtab[1];
1469         } else {
1470                 uint32_t *buckets;
1471                 uint32_t *hashval;
1472                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1473                 sym += p->ghashtab[1];
1474                 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1475                         if (buckets[i] > nsym)
1476                                 nsym = buckets[i];
1477                 }
1478                 if (nsym) {
1479                         nsym -= p->ghashtab[1];
1480                         hashval = buckets + p->ghashtab[0] + nsym;
1481                         do nsym++;
1482                         while (!(*hashval++ & 1));
1483                 }
1484         }
1485
1486         for (; nsym; nsym--, sym++) {
1487                 if (sym->st_value
1488                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1489                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1490                         void *symaddr = p->base + sym->st_value;
1491                         if (symaddr > addr || symaddr < best)
1492                                 continue;
1493                         best = symaddr;
1494                         bestname = strings + sym->st_name;
1495                         if (addr == symaddr)
1496                                 break;
1497                 }
1498         }
1499
1500         if (!best) return 0;
1501
1502         info->dli_fname = p->name;
1503         info->dli_fbase = p->base;
1504         info->dli_sname = bestname;
1505         info->dli_saddr = best;
1506
1507         return 1;
1508 }
1509
1510 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1511 {
1512         void *res;
1513         pthread_rwlock_rdlock(&lock);
1514         res = do_dlsym(p, s, ra);
1515         pthread_rwlock_unlock(&lock);
1516         return res;
1517 }
1518
1519 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1520 {
1521         struct dso *current;
1522         struct dl_phdr_info info;
1523         int ret = 0;
1524         for(current = head; current;) {
1525                 info.dlpi_addr      = (uintptr_t)current->base;
1526                 info.dlpi_name      = current->name;
1527                 info.dlpi_phdr      = current->phdr;
1528                 info.dlpi_phnum     = current->phnum;
1529                 info.dlpi_adds      = gencnt;
1530                 info.dlpi_subs      = 0;
1531                 info.dlpi_tls_modid = current->tls_id;
1532                 info.dlpi_tls_data  = current->tls_image;
1533
1534                 ret = (callback)(&info, sizeof (info), data);
1535
1536                 if (ret != 0) break;
1537
1538                 pthread_rwlock_rdlock(&lock);
1539                 current = current->next;
1540                 pthread_rwlock_unlock(&lock);
1541         }
1542         return ret;
1543 }
1544 #else
1545 static int invalid_dso_handle(void *h)
1546 {
1547         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1548         errflag = 1;
1549         return 1;
1550 }
1551 void *dlopen(const char *file, int mode)
1552 {
1553         return 0;
1554 }
1555 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1556 {
1557         return 0;
1558 }
1559 int __dladdr (const void *addr, Dl_info *info)
1560 {
1561         return 0;
1562 }
1563 #endif
1564
1565 int __dlinfo(void *dso, int req, void *res)
1566 {
1567         if (invalid_dso_handle(dso)) return -1;
1568         if (req != RTLD_DI_LINKMAP) {
1569                 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1570                 errflag = 1;
1571                 return -1;
1572         }
1573         *(struct link_map **)res = dso;
1574         return 0;
1575 }
1576
1577 char *dlerror()
1578 {
1579         if (!errflag) return 0;
1580         errflag = 0;
1581         return errbuf;
1582 }
1583
1584 int dlclose(void *p)
1585 {
1586         return invalid_dso_handle(p);
1587 }