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

   1 #define _GNU_SOURCE
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <stdarg.h>
   5 #include <string.h>
   6 #include <unistd.h>
   7 #include <stdint.h>
   8 #include <elf.h>
   9 #include <sys/mman.h>
  10 #include <limits.h>
  11 #include <fcntl.h>
  12 #include <sys/stat.h>
  13 #include <errno.h>
  14 #include <link.h>
  15 #include <setjmp.h>
  16 #include <pthread.h>
  17 #include <ctype.h>
  18 #include <dlfcn.h>
  19 #include "pthread_impl.h"
  20 #include "libc.h"
  21
  22 static int errflag;
  23 static char errbuf[128];
  24
  25 #ifdef SHARED
  26
  27 #if ULONG_MAX == 0xffffffff
  28 typedef Elf32_Ehdr Ehdr;
  29 typedef Elf32_Phdr Phdr;
  30 typedef Elf32_Sym Sym;
  31 #define R_TYPE(x) ((x)&255)
  32 #define R_SYM(x) ((x)>>8)
  33 #else
  34 typedef Elf64_Ehdr Ehdr;
  35 typedef Elf64_Phdr Phdr;
  36 typedef Elf64_Sym Sym;
  37 #define R_TYPE(x) ((x)&0xffffffff)
  38 #define R_SYM(x) ((x)>>32)
  39 #endif
  40
  41 #define MAXP2(a,b) (-(-(a)&-(b)))
  42 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  43
  44 struct debug {
  45         int ver;
  46         void *head;
  47         void (*bp)(void);
  48         int state;
  49         void *base;
  50 };
  51
  52 struct dso {
  53         unsigned char *base;
  54         char *name;
  55         size_t *dynv;
  56         struct dso *next, *prev;
  57
  58         Phdr *phdr;
  59         int phnum;
  60         size_t phentsize;
  61         int refcnt;
  62         Sym *syms;
  63         uint32_t *hashtab;
  64         uint32_t *ghashtab;
  65         int16_t *versym;
  66         char *strings;
  67         unsigned char *map;
  68         size_t map_len;
  69         dev_t dev;
  70         ino_t ino;
  71         signed char global;
  72         char relocated;
  73         char constructed;
  74         char kernel_mapped;
  75         struct dso **deps, *needed_by;
  76         char *rpath_orig, *rpath;
  77         void *tls_image;
  78         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  79         size_t relro_start, relro_end;
  80         void **new_dtv;
  81         unsigned char *new_tls;
  82         int new_dtv_idx, new_tls_idx;
  83         struct dso *fini_next;
  84         char *shortname;
  85         char buf[];
  86 };
  87
  88 struct symdef {
  89         Sym *sym;
  90         struct dso *dso;
  91 };
  92
  93 enum {
  94         REL_ERR,
  95         REL_SYMBOLIC,
  96         REL_GOT,
  97         REL_PLT,
  98         REL_RELATIVE,
  99         REL_OFFSET,
 100         REL_OFFSET32,
 101         REL_COPY,
 102         REL_SYM_OR_REL,
 103         REL_TLS, /* everything past here is TLS */
 104         REL_DTPMOD,
 105         REL_DTPOFF,
 106         REL_TPOFF,
 107         REL_TPOFF_NEG,
 108 };
 109
 110 #include "reloc.h"
 111
 112 int __init_tp(void *);
 113 void __init_libc(char **, char *);
 114
 115 const char *__libc_get_version(void);
 116
 117 static struct dso *head, *tail, *ldso, *fini_head;
 118 static char *env_path, *sys_path;
 119 static unsigned long long gencnt;
 120 static int runtime;
 121 static int ldd_mode;
 122 static int ldso_fail;
 123 static int noload;
 124 static jmp_buf *rtld_fail;
 125 static pthread_rwlock_t lock;
 126 static struct debug debug;
 127 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
 128 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 129 static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
 130
 131 struct debug *_dl_debug_addr = &debug;
 132
 133 #define AUX_CNT 38
 134 #define DYN_CNT 34
 135
 136 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 137 {
 138         memset(a, 0, cnt*sizeof(size_t));
 139         for (; v[0]; v+=2) if (v[0]<cnt) {
 140                 a[0] |= 1ULL<<v[0];
 141                 a[v[0]] = v[1];
 142         }
 143 }
 144
 145 static int search_vec(size_t *v, size_t *r, size_t key)
 146 {
 147         for (; v[0]!=key; v+=2)
 148                 if (!v[0]) return 0;
 149         *r = v[1];
 150         return 1;
 151 }
 152
 153 static void error(const char *fmt, ...)
 154 {
 155         va_list ap;
 156         va_start(ap, fmt);
 157         vsnprintf(errbuf, sizeof errbuf, fmt, ap);
 158         va_end(ap);
 159         if (runtime) longjmp(*rtld_fail, 1);
 160         dprintf(2, "%s\n", errbuf);
 161         ldso_fail = 1;
 162 }
 163
 164 static uint32_t sysv_hash(const char *s0)
 165 {
 166         const unsigned char *s = (void *)s0;
 167         uint_fast32_t h = 0;
 168         while (*s) {
 169                 h = 16*h + *s++;
 170                 h ^= h>>24 & 0xf0;
 171         }
 172         return h & 0xfffffff;
 173 }
 174
 175 static uint32_t gnu_hash(const char *s0)
 176 {
 177         const unsigned char *s = (void *)s0;
 178         uint_fast32_t h = 5381;
 179         for (; *s; s++)
 180                 h = h*33 + *s;
 181         return h;
 182 }
 183
 184 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 185 {
 186         size_t i;
 187         Sym *syms = dso->syms;
 188         uint32_t *hashtab = dso->hashtab;
 189         char *strings = dso->strings;
 190         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 191                 if ((!dso->versym || dso->versym[i] >= 0)
 192                     && (!strcmp(s, strings+syms[i].st_name)))
 193                         return syms+i;
 194         }
 195         return 0;
 196 }
 197
 198 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 199 {
 200         Sym *syms = dso->syms;
 201         char *strings = dso->strings;
 202         uint32_t *hashtab = dso->ghashtab;
 203         uint32_t nbuckets = hashtab[0];
 204         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 205         uint32_t h2;
 206         uint32_t *hashval;
 207         uint32_t i = buckets[h1 % nbuckets];
 208
 209         if (!i) return 0;
 210
 211         hashval = buckets + nbuckets + (i - hashtab[1]);
 212
 213         for (h1 |= 1; ; i++) {
 214                 h2 = *hashval++;
 215                 if ((!dso->versym || dso->versym[i] >= 0)
 216                     && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
 217                         return syms+i;
 218                 if (h2 & 1) break;
 219         }
 220
 221         return 0;
 222 }
 223
 224 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 225 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 226
 227 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 228 {
 229         uint32_t h = 0, gh = 0;
 230         struct symdef def = {0};
 231         for (; dso; dso=dso->next) {
 232                 Sym *sym;
 233                 if (!dso->global) continue;
 234                 if (dso->ghashtab) {
 235                         if (!gh) gh = gnu_hash(s);
 236                         sym = gnu_lookup(s, gh, dso);
 237                 } else {
 238                         if (!h) h = sysv_hash(s);
 239                         sym = sysv_lookup(s, h, dso);
 240                 }
 241                 if (!sym) continue;
 242                 if (!sym->st_shndx)
 243                         if (need_def || (sym->st_info&0xf) == STT_TLS)
 244                                 continue;
 245                 if (!sym->st_value)
 246                         if ((sym->st_info&0xf) != STT_TLS)
 247                                 continue;
 248                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 249                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 250
 251                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 252                 def.sym = sym;
 253                 def.dso = dso;
 254                 if (sym->st_info>>4 == STB_GLOBAL) break;
 255         }
 256         return def;
 257 }
 258
 259 #define NO_INLINE_ADDEND (1<<REL_COPY | 1<<REL_GOT | 1<<REL_PLT)
 260
 261 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 262 {
 263         unsigned char *base = dso->base;
 264         Sym *syms = dso->syms;
 265         char *strings = dso->strings;
 266         Sym *sym;
 267         const char *name;
 268         void *ctx;
 269         int astype, type;
 270         int sym_index;
 271         struct symdef def;
 272         size_t *reloc_addr;
 273         size_t sym_val;
 274         size_t tls_val;
 275         size_t addend;
 276
 277         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 278                 astype = R_TYPE(rel[1]);
 279                 if (!astype) continue;
 280                 type = remap_rel(astype);
 281                 if (!type) {
 282                         error(errbuf, sizeof errbuf,
 283                                 "Error relocating %s: unsupported relocation type %d",
 284                                 dso->name, astype);
 285                         continue;
 286                 }
 287                 sym_index = R_SYM(rel[1]);
 288                 reloc_addr = (void *)(base + rel[0]);
 289                 if (sym_index) {
 290                         sym = syms + sym_index;
 291                         name = strings + sym->st_name;
 292                         ctx = type==REL_COPY ? head->next : head;
 293                         def = find_sym(ctx, name, type==REL_PLT);
 294                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 295                             || sym->st_info>>4 != STB_WEAK)) {
 296                                 error(errbuf, sizeof errbuf,
 297                                         "Error relocating %s: %s: symbol not found",
 298                                         dso->name, name);
 299                                 continue;
 300                         }
 301                 } else {
 302                         sym = 0;
 303                         def.sym = 0;
 304                         def.dso = dso;
 305                 }
 306
 307                 addend = stride>2 ? rel[2]
 308                         : (1<<type & NO_INLINE_ADDEND) ? 0
 309                         : *reloc_addr;
 310
 311                 sym_val = def.sym ? (size_t)def.dso->base+def.sym->st_value : 0;
 312                 tls_val = def.sym ? def.sym->st_value : 0;
 313
 314                 switch(type) {
 315                 case REL_OFFSET:
 316                         addend -= (size_t)reloc_addr;
 317                 case REL_SYMBOLIC:
 318                 case REL_GOT:
 319                 case REL_PLT:
 320                         *reloc_addr = sym_val + addend;
 321                         break;
 322                 case REL_RELATIVE:
 323                         *reloc_addr = (size_t)base + addend;
 324                         break;
 325                 case REL_SYM_OR_REL:
 326                         if (sym) *reloc_addr = sym_val + addend;
 327                         else *reloc_addr = (size_t)base + addend;
 328                         break;
 329                 case REL_COPY:
 330                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 331                         break;
 332                 case REL_OFFSET32:
 333                         *(uint32_t *)reloc_addr = sym_val + addend
 334                                 - (size_t)reloc_addr;
 335                         break;
 336                 case REL_DTPMOD:
 337                         *reloc_addr = def.dso->tls_id;
 338                         break;
 339                 case REL_DTPOFF:
 340                         *reloc_addr = tls_val + addend;
 341                         break;
 342 #ifdef TLS_ABOVE_TP
 343                 case REL_TPOFF:
 344                         *reloc_addr = tls_val + def.dso->tls_offset + TPOFF_K + addend;
 345                         break;
 346 #else
 347                 case REL_TPOFF:
 348                         *reloc_addr = tls_val - def.dso->tls_offset + addend;
 349                         break;
 350                 case REL_TPOFF_NEG:
 351                         *reloc_addr = def.dso->tls_offset - tls_val + addend;
 352                         break;
 353 #endif
 354                 }
 355         }
 356 }
 357
 358 /* A huge hack: to make up for the wastefulness of shared libraries
 359  * needing at least a page of dirty memory even if they have no global
 360  * data, we reclaim the gaps at the beginning and end of writable maps
 361  * and "donate" them to the heap by setting up minimal malloc
 362  * structures and then freeing them. */
 363
 364 static void reclaim(struct dso *dso, size_t start, size_t end)
 365 {
 366         size_t *a, *z;
 367         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 368         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 369         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 370         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 371         if (start>end || end-start < 4*sizeof(size_t)) return;
 372         a = (size_t *)(dso->base + start);
 373         z = (size_t *)(dso->base + end);
 374         a[-2] = 1;
 375         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 376         z[1] = 1;
 377         free(a);
 378 }
 379
 380 static void reclaim_gaps(struct dso *dso)
 381 {
 382         Phdr *ph = dso->phdr;
 383         size_t phcnt = dso->phnum;
 384
 385         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 386                 if (ph->p_type!=PT_LOAD) continue;
 387                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 388                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 389                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 390                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 391         }
 392 }
 393
 394 static void *map_library(int fd, struct dso *dso)
 395 {
 396         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 397         void *allocated_buf=0;
 398         size_t phsize;
 399         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 400         size_t this_min, this_max;
 401         off_t off_start;
 402         Ehdr *eh;
 403         Phdr *ph, *ph0;
 404         unsigned prot;
 405         unsigned char *map=MAP_FAILED, *base;
 406         size_t dyn=0;
 407         size_t tls_image=0;
 408         size_t i;
 409
 410         ssize_t l = read(fd, buf, sizeof buf);
 411         eh = buf;
 412         if (l<0) return 0;
 413         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 414                 goto noexec;
 415         phsize = eh->e_phentsize * eh->e_phnum;
 416         if (phsize > sizeof buf - sizeof *eh) {
 417                 allocated_buf = malloc(phsize);
 418                 if (!allocated_buf) return 0;
 419                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 420                 if (l < 0) goto error;
 421                 if (l != phsize) goto noexec;
 422                 ph = ph0 = allocated_buf;
 423         } else if (eh->e_phoff + phsize > l) {
 424                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 425                 if (l < 0) goto error;
 426                 if (l != phsize) goto noexec;
 427                 ph = ph0 = (void *)(buf + 1);
 428         } else {
 429                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 430         }
 431         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 432                 if (ph->p_type == PT_DYNAMIC) {
 433                         dyn = ph->p_vaddr;
 434                 } else if (ph->p_type == PT_TLS) {
 435                         tls_image = ph->p_vaddr;
 436                         dso->tls_align = ph->p_align;
 437                         dso->tls_len = ph->p_filesz;
 438                         dso->tls_size = ph->p_memsz;
 439                 } else if (ph->p_type == PT_GNU_RELRO) {
 440                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 441                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 442                 }
 443                 if (ph->p_type != PT_LOAD) continue;
 444                 if (ph->p_vaddr < addr_min) {
 445                         addr_min = ph->p_vaddr;
 446                         off_start = ph->p_offset;
 447                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 448                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 449                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 450                 }
 451                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 452                         addr_max = ph->p_vaddr+ph->p_memsz;
 453                 }
 454         }
 455         if (!dyn) goto noexec;
 456         addr_max += PAGE_SIZE-1;
 457         addr_max &= -PAGE_SIZE;
 458         addr_min &= -PAGE_SIZE;
 459         off_start &= -PAGE_SIZE;
 460         map_len = addr_max - addr_min + off_start;
 461         /* The first time, we map too much, possibly even more than
 462          * the length of the file. This is okay because we will not
 463          * use the invalid part; we just need to reserve the right
 464          * amount of virtual address space to map over later. */
 465         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 466         if (map==MAP_FAILED) goto error;
 467         /* If the loaded file is not relocatable and the requested address is
 468          * not available, then the load operation must fail. */
 469         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 470                 errno = EBUSY;
 471                 goto error;
 472         }
 473         base = map - addr_min;
 474         dso->phdr = 0;
 475         dso->phnum = 0;
 476         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 477                 if (ph->p_type != PT_LOAD) continue;
 478                 /* Check if the programs headers are in this load segment, and
 479                  * if so, record the address for use by dl_iterate_phdr. */
 480                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 481                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 482                         dso->phdr = (void *)(base + ph->p_vaddr
 483                                 + (eh->e_phoff-ph->p_offset));
 484                         dso->phnum = eh->e_phnum;
 485                         dso->phentsize = eh->e_phentsize;
 486                 }
 487                 /* Reuse the existing mapping for the lowest-address LOAD */
 488                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 489                 this_min = ph->p_vaddr & -PAGE_SIZE;
 490                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 491                 off_start = ph->p_offset & -PAGE_SIZE;
 492                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 493                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 494                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 495                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 496                         goto error;
 497                 if (ph->p_memsz > ph->p_filesz) {
 498                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 499                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 500                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 501                         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)
 502                                 goto error;
 503                 }
 504         }
 505         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 506                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 507                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 508                                 goto error;
 509                         break;
 510                 }
 511         dso->map = map;
 512         dso->map_len = map_len;
 513         dso->base = base;
 514         dso->dynv = (void *)(base+dyn);
 515         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 516         if (!runtime) reclaim_gaps(dso);
 517         free(allocated_buf);
 518         return map;
 519 noexec:
 520         errno = ENOEXEC;
 521 error:
 522         if (map!=MAP_FAILED) munmap(map, map_len);
 523         free(allocated_buf);
 524         return 0;
 525 }
 526
 527 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 528 {
 529         size_t l;
 530         int fd;
 531         for (;;) {
 532                 s += strspn(s, ":\n");
 533                 l = strcspn(s, ":\n");
 534                 if (l-1 >= INT_MAX) return -1;
 535                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
 536                         continue;
 537                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 538                 s += l;
 539         }
 540 }
 541
 542 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 543 {
 544         size_t n, l;
 545         const char *s, *t, *origin;
 546         char *d;
 547         if (p->rpath) return 0;
 548         if (!p->rpath_orig) return -1;
 549         if (!strchr(p->rpath_orig, '$')) {
 550                 p->rpath = p->rpath_orig;
 551                 return 0;
 552         }
 553         n = 0;
 554         s = p->rpath_orig;
 555         while ((t=strchr(s, '$'))) {
 556                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 557                         return -1;
 558                 s = t+1;
 559                 n++;
 560         }
 561         if (n > SSIZE_MAX/PATH_MAX) return -1;
 562
 563         if (p->kernel_mapped) {
 564                 /* $ORIGIN searches cannot be performed for the main program
 565                  * when it is suid/sgid/AT_SECURE. This is because the
 566                  * pathname is under the control of the caller of execve.
 567                  * For libraries, however, $ORIGIN can be processed safely
 568                  * since the library's pathname came from a trusted source
 569                  * (either system paths or a call to dlopen). */
 570                 if (libc.secure)
 571                         return -1;
 572                 l = readlink("/proc/self/exe", buf, buf_size);
 573                 if (l >= buf_size)
 574                         return -1;
 575                 buf[l] = 0;
 576                 origin = buf;
 577         } else {
 578                 origin = p->name;
 579         }
 580         t = strrchr(origin, '/');
 581         l = t ? t-origin : 0;
 582         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 583         if (!p->rpath) return -1;
 584
 585         d = p->rpath;
 586         s = p->rpath_orig;
 587         while ((t=strchr(s, '$'))) {
 588                 memcpy(d, s, t-s);
 589                 d += t-s;
 590                 memcpy(d, origin, l);
 591                 d += l;
 592                 /* It was determined previously that the '$' is followed
 593                  * either by "ORIGIN" or "{ORIGIN}". */
 594                 s = t + 7 + 2*(t[1]=='{');
 595         }
 596         strcpy(d, s);
 597         return 0;
 598 }
 599
 600 static void decode_dyn(struct dso *p)
 601 {
 602         size_t dyn[DYN_CNT] = {0};
 603         decode_vec(p->dynv, dyn, DYN_CNT);
 604         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 605         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 606         if (dyn[0]&(1<<DT_HASH))
 607                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 608         if (dyn[0]&(1<<DT_RPATH))
 609                 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
 610         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 611                 p->ghashtab = (void *)(p->base + *dyn);
 612         if (search_vec(p->dynv, dyn, DT_VERSYM))
 613                 p->versym = (void *)(p->base + *dyn);
 614 }
 615
 616 static struct dso *load_library(const char *name, struct dso *needed_by)
 617 {
 618         char buf[2*NAME_MAX+2];
 619         const char *pathname;
 620         unsigned char *map;
 621         struct dso *p, temp_dso = {0};
 622         int fd;
 623         struct stat st;
 624         size_t alloc_size;
 625         int n_th = 0;
 626         int is_self = 0;
 627
 628         /* Catch and block attempts to reload the implementation itself */
 629         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 630                 static const char *rp, reserved[] =
 631                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 632                 char *z = strchr(name, '.');
 633                 if (z) {
 634                         size_t l = z-name;
 635                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 636                         if (*rp) {
 637                                 if (ldd_mode) {
 638                                         /* Track which names have been resolved
 639                                          * and only report each one once. */
 640                                         static unsigned reported;
 641                                         unsigned mask = 1U<<(rp-reserved);
 642                                         if (!(reported & mask)) {
 643                                                 reported |= mask;
 644                                                 dprintf(1, "\t%s => %s (%p)\n",
 645                                                         name, ldso->name,
 646                                                         ldso->base);
 647                                         }
 648                                 }
 649                                 is_self = 1;
 650                         }
 651                 }
 652         }
 653         if (!strcmp(name, ldso->name)) is_self = 1;
 654         if (is_self) {
 655                 if (!ldso->prev) {
 656                         tail->next = ldso;
 657                         ldso->prev = tail;
 658                         tail = ldso->next ? ldso->next : ldso;
 659                 }
 660                 return ldso;
 661         }
 662         if (strchr(name, '/')) {
 663                 pathname = name;
 664                 fd = open(name, O_RDONLY|O_CLOEXEC);
 665         } else {
 666                 /* Search for the name to see if it's already loaded */
 667                 for (p=head->next; p; p=p->next) {
 668                         if (p->shortname && !strcmp(p->shortname, name)) {
 669                                 p->refcnt++;
 670                                 return p;
 671                         }
 672                 }
 673                 if (strlen(name) > NAME_MAX) return 0;
 674                 fd = -1;
 675                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 676                 for (p=needed_by; fd < 0 && p; p=p->needed_by)
 677                         if (!fixup_rpath(p, buf, sizeof buf))
 678                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 679                 if (fd < 0) {
 680                         if (!sys_path) {
 681                                 char *prefix = 0;
 682                                 size_t prefix_len;
 683                                 if (ldso->name[0]=='/') {
 684                                         char *s, *t, *z;
 685                                         for (s=t=z=ldso->name; *s; s++)
 686                                                 if (*s=='/') z=t, t=s;
 687                                         prefix_len = z-ldso->name;
 688                                         if (prefix_len < PATH_MAX)
 689                                                 prefix = ldso->name;
 690                                 }
 691                                 if (!prefix) {
 692                                         prefix = "";
 693                                         prefix_len = 0;
 694                                 }
 695                                 char etc_ldso_path[prefix_len + 1
 696                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 697                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 698                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 699                                         (int)prefix_len, prefix);
 700                                 FILE *f = fopen(etc_ldso_path, "rbe");
 701                                 if (f) {
 702                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 703                                                 free(sys_path);
 704                                                 sys_path = "";
 705                                         }
 706                                         fclose(f);
 707                                 } else if (errno != ENOENT) {
 708                                         sys_path = "";
 709                                 }
 710                         }
 711                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 712                         fd = path_open(name, sys_path, buf, sizeof buf);
 713                 }
 714                 pathname = buf;
 715         }
 716         if (fd < 0) return 0;
 717         if (fstat(fd, &st) < 0) {
 718                 close(fd);
 719                 return 0;
 720         }
 721         for (p=head->next; p; p=p->next) {
 722                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 723                         /* If this library was previously loaded with a
 724                          * pathname but a search found the same inode,
 725                          * setup its shortname so it can be found by name. */
 726                         if (!p->shortname && pathname != name)
 727                                 p->shortname = strrchr(p->name, '/')+1;
 728                         close(fd);
 729                         p->refcnt++;
 730                         return p;
 731                 }
 732         }
 733         map = noload ? 0 : map_library(fd, &temp_dso);
 734         close(fd);
 735         if (!map) return 0;
 736
 737         /* Allocate storage for the new DSO. When there is TLS, this
 738          * storage must include a reservation for all pre-existing
 739          * threads to obtain copies of both the new TLS, and an
 740          * extended DTV capable of storing an additional slot for
 741          * the newly-loaded DSO. */
 742         alloc_size = sizeof *p + strlen(pathname) + 1;
 743         if (runtime && temp_dso.tls_image) {
 744                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 745                         + sizeof(void *) * (tls_cnt+3);
 746                 n_th = libc.threads_minus_1 + 1;
 747                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 748                 else alloc_size += n_th * per_th;
 749         }
 750         p = calloc(1, alloc_size);
 751         if (!p) {
 752                 munmap(map, temp_dso.map_len);
 753                 return 0;
 754         }
 755         memcpy(p, &temp_dso, sizeof temp_dso);
 756         decode_dyn(p);
 757         p->dev = st.st_dev;
 758         p->ino = st.st_ino;
 759         p->refcnt = 1;
 760         p->needed_by = needed_by;
 761         p->name = p->buf;
 762         strcpy(p->name, pathname);
 763         /* Add a shortname only if name arg was not an explicit pathname. */
 764         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 765         if (p->tls_image) {
 766                 if (runtime && !libc.has_thread_pointer) {
 767                         munmap(map, p->map_len);
 768                         free(p);
 769                         errno = ENOSYS;
 770                         return 0;
 771                 }
 772                 p->tls_id = ++tls_cnt;
 773                 tls_align = MAXP2(tls_align, p->tls_align);
 774 #ifdef TLS_ABOVE_TP
 775                 p->tls_offset = tls_offset + ( (tls_align-1) &
 776                         -(tls_offset + (uintptr_t)p->tls_image) );
 777                 tls_offset += p->tls_size;
 778 #else
 779                 tls_offset += p->tls_size + p->tls_align - 1;
 780                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 781                         & (p->tls_align-1);
 782                 p->tls_offset = tls_offset;
 783 #endif
 784                 p->new_dtv = (void *)(-sizeof(size_t) &
 785                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 786                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 787         }
 788
 789         tail->next = p;
 790         p->prev = tail;
 791         tail = p;
 792
 793         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 794
 795         return p;
 796 }
 797
 798 static void load_deps(struct dso *p)
 799 {
 800         size_t i, ndeps=0;
 801         struct dso ***deps = &p->deps, **tmp, *dep;
 802         for (; p; p=p->next) {
 803                 for (i=0; p->dynv[i]; i+=2) {
 804                         if (p->dynv[i] != DT_NEEDED) continue;
 805                         dep = load_library(p->strings + p->dynv[i+1], p);
 806                         if (!dep) {
 807                                 error(errbuf, sizeof errbuf,
 808                                         "Error loading shared library %s: %m (needed by %s)",
 809                                         p->strings + p->dynv[i+1], p->name);
 810                                 continue;
 811                         }
 812                         if (runtime) {
 813                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 814                                 if (!tmp) longjmp(*rtld_fail, 1);
 815                                 tmp[ndeps++] = dep;
 816                                 tmp[ndeps] = 0;
 817                                 *deps = tmp;
 818                         }
 819                 }
 820         }
 821 }
 822
 823 static void load_preload(char *s)
 824 {
 825         int tmp;
 826         char *z;
 827         for (z=s; *z; s=z) {
 828                 for (   ; *s && isspace(*s); s++);
 829                 for (z=s; *z && !isspace(*z); z++);
 830                 tmp = *z;
 831                 *z = 0;
 832                 load_library(s, 0);
 833                 *z = tmp;
 834         }
 835 }
 836
 837 static void make_global(struct dso *p)
 838 {
 839         for (; p; p=p->next) p->global = 1;
 840 }
 841
 842 static void reloc_all(struct dso *p)
 843 {
 844         size_t dyn[DYN_CNT] = {0};
 845         for (; p; p=p->next) {
 846                 if (p->relocated) continue;
 847                 decode_vec(p->dynv, dyn, DYN_CNT);
 848 #ifdef NEED_ARCH_RELOCS
 849                 do_arch_relocs(p, head);
 850 #endif
 851                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 852                         2+(dyn[DT_PLTREL]==DT_RELA));
 853                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 854                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 855
 856                 if (p->relro_start != p->relro_end &&
 857                     mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) {
 858                         error(errbuf, sizeof errbuf,
 859                                 "Error relocating %s: RELRO protection failed: %m",
 860                                 p->name);
 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 }