src/ldso/dynlink.c

   1 #define _GNU_SOURCE
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <stdarg.h>
   5 #include <stddef.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <stdint.h>
   9 #include <elf.h>
  10 #include <sys/mman.h>
  11 #include <limits.h>
  12 #include <fcntl.h>
  13 #include <sys/stat.h>
  14 #include <errno.h>
  15 #include <link.h>
  16 #include <setjmp.h>
  17 #include <pthread.h>
  18 #include <ctype.h>
  19 #include <dlfcn.h>
  20 #include "pthread_impl.h"
  21 #include "libc.h"
  22
  23 static int errflag;
  24 static char errbuf[128];
  25
  26 #ifdef SHARED
  27
  28 #if ULONG_MAX == 0xffffffff
  29 typedef Elf32_Ehdr Ehdr;
  30 typedef Elf32_Phdr Phdr;
  31 typedef Elf32_Sym Sym;
  32 #define R_TYPE(x) ((x)&255)
  33 #define R_SYM(x) ((x)>>8)
  34 #else
  35 typedef Elf64_Ehdr Ehdr;
  36 typedef Elf64_Phdr Phdr;
  37 typedef Elf64_Sym Sym;
  38 #define R_TYPE(x) ((x)&0xffffffff)
  39 #define R_SYM(x) ((x)>>32)
  40 #endif
  41
  42 #define MAXP2(a,b) (-(-(a)&-(b)))
  43 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  44
  45 struct debug {
  46         int ver;
  47         void *head;
  48         void (*bp)(void);
  49         int state;
  50         void *base;
  51 };
  52
  53 struct td_index {
  54         size_t args[2];
  55         struct td_index *next;
  56 };
  57
  58 struct dso {
  59         unsigned char *base;
  60         char *name;
  61         size_t *dynv;
  62         struct dso *next, *prev;
  63
  64         Phdr *phdr;
  65         int phnum;
  66         size_t phentsize;
  67         int refcnt;
  68         Sym *syms;
  69         uint32_t *hashtab;
  70         uint32_t *ghashtab;
  71         int16_t *versym;
  72         char *strings;
  73         unsigned char *map;
  74         size_t map_len;
  75         dev_t dev;
  76         ino_t ino;
  77         signed char global;
  78         char relocated;
  79         char constructed;
  80         char kernel_mapped;
  81         struct dso **deps, *needed_by;
  82         char *rpath_orig, *rpath;
  83         void *tls_image;
  84         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  85         size_t relro_start, relro_end;
  86         void **new_dtv;
  87         unsigned char *new_tls;
  88         int new_dtv_idx, new_tls_idx;
  89         struct td_index *td_index;
  90         struct dso *fini_next;
  91         char *shortname;
  92         char buf[];
  93 };
  94
  95 struct symdef {
  96         Sym *sym;
  97         struct dso *dso;
  98 };
  99
 100 enum {
 101         REL_ERR,
 102         REL_SYMBOLIC,
 103         REL_GOT,
 104         REL_PLT,
 105         REL_RELATIVE,
 106         REL_OFFSET,
 107         REL_OFFSET32,
 108         REL_COPY,
 109         REL_SYM_OR_REL,
 110         REL_TLS, /* everything past here is TLS */
 111         REL_DTPMOD,
 112         REL_DTPOFF,
 113         REL_TPOFF,
 114         REL_TPOFF_NEG,
 115         REL_TLSDESC,
 116 };
 117
 118 #include "reloc.h"
 119
 120 int __init_tp(void *);
 121 void __init_libc(char **, char *);
 122
 123 const char *__libc_get_version(void);
 124
 125 static struct dso *head, *tail, *ldso, *fini_head;
 126 static char *env_path, *sys_path;
 127 static unsigned long long gencnt;
 128 static int runtime;
 129 static int ldd_mode;
 130 static int ldso_fail;
 131 static int noload;
 132 static jmp_buf *rtld_fail;
 133 static pthread_rwlock_t lock;
 134 static struct debug debug;
 135 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
 136 static size_t static_tls_cnt;
 137 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 138 static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
 139
 140 struct debug *_dl_debug_addr = &debug;
 141
 142 #define AUX_CNT 38
 143 #define DYN_CNT 34
 144
 145 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 146 {
 147         memset(a, 0, cnt*sizeof(size_t));
 148         for (; v[0]; v+=2) if (v[0]<cnt) {
 149                 a[0] |= 1ULL<<v[0];
 150                 a[v[0]] = v[1];
 151         }
 152 }
 153
 154 static int search_vec(size_t *v, size_t *r, size_t key)
 155 {
 156         for (; v[0]!=key; v+=2)
 157                 if (!v[0]) return 0;
 158         *r = v[1];
 159         return 1;
 160 }
 161
 162 static void error(const char *fmt, ...)
 163 {
 164         va_list ap;
 165         va_start(ap, fmt);
 166         vsnprintf(errbuf, sizeof errbuf, fmt, ap);
 167         va_end(ap);
 168         if (runtime) longjmp(*rtld_fail, 1);
 169         dprintf(2, "%s\n", errbuf);
 170         ldso_fail = 1;
 171 }
 172
 173 static uint32_t sysv_hash(const char *s0)
 174 {
 175         const unsigned char *s = (void *)s0;
 176         uint_fast32_t h = 0;
 177         while (*s) {
 178                 h = 16*h + *s++;
 179                 h ^= h>>24 & 0xf0;
 180         }
 181         return h & 0xfffffff;
 182 }
 183
 184 static uint32_t gnu_hash(const char *s0)
 185 {
 186         const unsigned char *s = (void *)s0;
 187         uint_fast32_t h = 5381;
 188         for (; *s; s++)
 189                 h = h*33 + *s;
 190         return h;
 191 }
 192
 193 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 194 {
 195         size_t i;
 196         Sym *syms = dso->syms;
 197         uint32_t *hashtab = dso->hashtab;
 198         char *strings = dso->strings;
 199         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 200                 if ((!dso->versym || dso->versym[i] >= 0)
 201                     && (!strcmp(s, strings+syms[i].st_name)))
 202                         return syms+i;
 203         }
 204         return 0;
 205 }
 206
 207 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 208 {
 209         Sym *syms = dso->syms;
 210         char *strings = dso->strings;
 211         uint32_t *hashtab = dso->ghashtab;
 212         uint32_t nbuckets = hashtab[0];
 213         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 214         uint32_t h2;
 215         uint32_t *hashval;
 216         uint32_t i = buckets[h1 % nbuckets];
 217
 218         if (!i) return 0;
 219
 220         hashval = buckets + nbuckets + (i - hashtab[1]);
 221
 222         for (h1 |= 1; ; i++) {
 223                 h2 = *hashval++;
 224                 if ((!dso->versym || dso->versym[i] >= 0)
 225                     && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
 226                         return syms+i;
 227                 if (h2 & 1) break;
 228         }
 229
 230         return 0;
 231 }
 232
 233 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 234 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 235
 236 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 237 {
 238         uint32_t h = 0, gh = 0;
 239         struct symdef def = {0};
 240         for (; dso; dso=dso->next) {
 241                 Sym *sym;
 242                 if (!dso->global) continue;
 243                 if (dso->ghashtab) {
 244                         if (!gh) gh = gnu_hash(s);
 245                         sym = gnu_lookup(s, gh, dso);
 246                 } else {
 247                         if (!h) h = sysv_hash(s);
 248                         sym = sysv_lookup(s, h, dso);
 249                 }
 250                 if (!sym) continue;
 251                 if (!sym->st_shndx)
 252                         if (need_def || (sym->st_info&0xf) == STT_TLS)
 253                                 continue;
 254                 if (!sym->st_value)
 255                         if ((sym->st_info&0xf) != STT_TLS)
 256                                 continue;
 257                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 258                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 259
 260                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 261                 def.sym = sym;
 262                 def.dso = dso;
 263                 if (sym->st_info>>4 == STB_GLOBAL) break;
 264         }
 265         return def;
 266 }
 267
 268 #define NO_INLINE_ADDEND (1<<REL_COPY | 1<<REL_GOT | 1<<REL_PLT)
 269
 270 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
 271
 272 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 273 {
 274         unsigned char *base = dso->base;
 275         Sym *syms = dso->syms;
 276         char *strings = dso->strings;
 277         Sym *sym;
 278         const char *name;
 279         void *ctx;
 280         int astype, type;
 281         int sym_index;
 282         struct symdef def;
 283         size_t *reloc_addr;
 284         size_t sym_val;
 285         size_t tls_val;
 286         size_t addend;
 287
 288         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 289                 astype = R_TYPE(rel[1]);
 290                 if (!astype) continue;
 291                 type = remap_rel(astype);
 292                 if (!type) {
 293                         error(errbuf, sizeof errbuf,
 294                                 "Error relocating %s: unsupported relocation type %d",
 295                                 dso->name, astype);
 296                         continue;
 297                 }
 298                 sym_index = R_SYM(rel[1]);
 299                 reloc_addr = (void *)(base + rel[0]);
 300                 if (sym_index) {
 301                         sym = syms + sym_index;
 302                         name = strings + sym->st_name;
 303                         ctx = type==REL_COPY ? head->next : head;
 304                         def = find_sym(ctx, name, type==REL_PLT);
 305                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 306                             || sym->st_info>>4 != STB_WEAK)) {
 307                                 error(errbuf, sizeof errbuf,
 308                                         "Error relocating %s: %s: symbol not found",
 309                                         dso->name, name);
 310                                 continue;
 311                         }
 312                 } else {
 313                         sym = 0;
 314                         def.sym = 0;
 315                         def.dso = dso;
 316                 }
 317
 318                 addend = stride>2 ? rel[2]
 319                         : (1<<type & NO_INLINE_ADDEND) ? 0
 320                         : *reloc_addr;
 321
 322                 sym_val = def.sym ? (size_t)def.dso->base+def.sym->st_value : 0;
 323                 tls_val = def.sym ? def.sym->st_value : 0;
 324
 325                 switch(type) {
 326                 case REL_OFFSET:
 327                         addend -= (size_t)reloc_addr;
 328                 case REL_SYMBOLIC:
 329                 case REL_GOT:
 330                 case REL_PLT:
 331                         *reloc_addr = sym_val + addend;
 332                         break;
 333                 case REL_RELATIVE:
 334                         *reloc_addr = (size_t)base + addend;
 335                         break;
 336                 case REL_SYM_OR_REL:
 337                         if (sym) *reloc_addr = sym_val + addend;
 338                         else *reloc_addr = (size_t)base + addend;
 339                         break;
 340                 case REL_COPY:
 341                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 342                         break;
 343                 case REL_OFFSET32:
 344                         *(uint32_t *)reloc_addr = sym_val + addend
 345                                 - (size_t)reloc_addr;
 346                         break;
 347                 case REL_DTPMOD:
 348                         *reloc_addr = def.dso->tls_id;
 349                         break;
 350                 case REL_DTPOFF:
 351                         *reloc_addr = tls_val + addend;
 352                         break;
 353 #ifdef TLS_ABOVE_TP
 354                 case REL_TPOFF:
 355                         *reloc_addr = tls_val + def.dso->tls_offset + TPOFF_K + addend;
 356                         break;
 357 #else
 358                 case REL_TPOFF:
 359                         *reloc_addr = tls_val - def.dso->tls_offset + addend;
 360                         break;
 361                 case REL_TPOFF_NEG:
 362                         *reloc_addr = def.dso->tls_offset - tls_val + addend;
 363                         break;
 364 #endif
 365                 case REL_TLSDESC:
 366                         if (stride<3) addend = reloc_addr[1];
 367                         if (runtime && def.dso->tls_id >= static_tls_cnt) {
 368                                 struct td_index *new = malloc(sizeof *new);
 369                                 if (!new) error(errbuf, sizeof errbuf,
 370                                         "Error relocating %s: cannot allocate TLSDESC for %s",
 371                                         dso->name, sym ? name : "(local)" );
 372                                 new->next = dso->td_index;
 373                                 dso->td_index = new;
 374                                 new->args[0] = def.dso->tls_id;
 375                                 new->args[1] = tls_val + addend;
 376                                 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
 377                                 reloc_addr[1] = (size_t)new;
 378                         } else {
 379                                 reloc_addr[0] = (size_t)__tlsdesc_static;
 380 #ifdef TLS_ABOVE_TP
 381                                 reloc_addr[1] = tls_val + def.dso->tls_offset
 382                                         + TPOFF_K + addend;
 383 #else
 384                                 reloc_addr[1] = tls_val - def.dso->tls_offset
 385                                         + addend;
 386 #endif
 387                         }
 388                         break;
 389                 }
 390         }
 391 }
 392
 393 /* A huge hack: to make up for the wastefulness of shared libraries
 394  * needing at least a page of dirty memory even if they have no global
 395  * data, we reclaim the gaps at the beginning and end of writable maps
 396  * and "donate" them to the heap by setting up minimal malloc
 397  * structures and then freeing them. */
 398
 399 static void reclaim(struct dso *dso, size_t start, size_t end)
 400 {
 401         size_t *a, *z;
 402         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 403         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 404         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 405         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 406         if (start>end || end-start < 4*sizeof(size_t)) return;
 407         a = (size_t *)(dso->base + start);
 408         z = (size_t *)(dso->base + end);
 409         a[-2] = 1;
 410         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 411         z[1] = 1;
 412         free(a);
 413 }
 414
 415 static void reclaim_gaps(struct dso *dso)
 416 {
 417         Phdr *ph = dso->phdr;
 418         size_t phcnt = dso->phnum;
 419
 420         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 421                 if (ph->p_type!=PT_LOAD) continue;
 422                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 423                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 424                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 425                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 426         }
 427 }
 428
 429 static void *map_library(int fd, struct dso *dso)
 430 {
 431         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 432         void *allocated_buf=0;
 433         size_t phsize;
 434         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 435         size_t this_min, this_max;
 436         off_t off_start;
 437         Ehdr *eh;
 438         Phdr *ph, *ph0;
 439         unsigned prot;
 440         unsigned char *map=MAP_FAILED, *base;
 441         size_t dyn=0;
 442         size_t tls_image=0;
 443         size_t i;
 444
 445         ssize_t l = read(fd, buf, sizeof buf);
 446         eh = buf;
 447         if (l<0) return 0;
 448         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 449                 goto noexec;
 450         phsize = eh->e_phentsize * eh->e_phnum;
 451         if (phsize > sizeof buf - sizeof *eh) {
 452                 allocated_buf = malloc(phsize);
 453                 if (!allocated_buf) return 0;
 454                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 455                 if (l < 0) goto error;
 456                 if (l != phsize) goto noexec;
 457                 ph = ph0 = allocated_buf;
 458         } else if (eh->e_phoff + phsize > l) {
 459                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 460                 if (l < 0) goto error;
 461                 if (l != phsize) goto noexec;
 462                 ph = ph0 = (void *)(buf + 1);
 463         } else {
 464                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 465         }
 466         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 467                 if (ph->p_type == PT_DYNAMIC) {
 468                         dyn = ph->p_vaddr;
 469                 } else if (ph->p_type == PT_TLS) {
 470                         tls_image = ph->p_vaddr;
 471                         dso->tls_align = ph->p_align;
 472                         dso->tls_len = ph->p_filesz;
 473                         dso->tls_size = ph->p_memsz;
 474                 } else if (ph->p_type == PT_GNU_RELRO) {
 475                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 476                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 477                 }
 478                 if (ph->p_type != PT_LOAD) continue;
 479                 if (ph->p_vaddr < addr_min) {
 480                         addr_min = ph->p_vaddr;
 481                         off_start = ph->p_offset;
 482                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 483                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 484                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 485                 }
 486                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 487                         addr_max = ph->p_vaddr+ph->p_memsz;
 488                 }
 489         }
 490         if (!dyn) goto noexec;
 491         addr_max += PAGE_SIZE-1;
 492         addr_max &= -PAGE_SIZE;
 493         addr_min &= -PAGE_SIZE;
 494         off_start &= -PAGE_SIZE;
 495         map_len = addr_max - addr_min + off_start;
 496         /* The first time, we map too much, possibly even more than
 497          * the length of the file. This is okay because we will not
 498          * use the invalid part; we just need to reserve the right
 499          * amount of virtual address space to map over later. */
 500         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 501         if (map==MAP_FAILED) goto error;
 502         /* If the loaded file is not relocatable and the requested address is
 503          * not available, then the load operation must fail. */
 504         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 505                 errno = EBUSY;
 506                 goto error;
 507         }
 508         base = map - addr_min;
 509         dso->phdr = 0;
 510         dso->phnum = 0;
 511         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 512                 if (ph->p_type != PT_LOAD) continue;
 513                 /* Check if the programs headers are in this load segment, and
 514                  * if so, record the address for use by dl_iterate_phdr. */
 515                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 516                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 517                         dso->phdr = (void *)(base + ph->p_vaddr
 518                                 + (eh->e_phoff-ph->p_offset));
 519                         dso->phnum = eh->e_phnum;
 520                         dso->phentsize = eh->e_phentsize;
 521                 }
 522                 /* Reuse the existing mapping for the lowest-address LOAD */
 523                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 524                 this_min = ph->p_vaddr & -PAGE_SIZE;
 525                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 526                 off_start = ph->p_offset & -PAGE_SIZE;
 527                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 528                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 529                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 530                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 531                         goto error;
 532                 if (ph->p_memsz > ph->p_filesz) {
 533                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 534                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 535                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 536                         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)
 537                                 goto error;
 538                 }
 539         }
 540         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 541                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 542                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 543                                 goto error;
 544                         break;
 545                 }
 546         dso->map = map;
 547         dso->map_len = map_len;
 548         dso->base = base;
 549         dso->dynv = (void *)(base+dyn);
 550         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 551         if (!runtime) reclaim_gaps(dso);
 552         free(allocated_buf);
 553         return map;
 554 noexec:
 555         errno = ENOEXEC;
 556 error:
 557         if (map!=MAP_FAILED) munmap(map, map_len);
 558         free(allocated_buf);
 559         return 0;
 560 }
 561
 562 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 563 {
 564         size_t l;
 565         int fd;
 566         for (;;) {
 567                 s += strspn(s, ":\n");
 568                 l = strcspn(s, ":\n");
 569                 if (l-1 >= INT_MAX) return -1;
 570                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
 571                         continue;
 572                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 573                 s += l;
 574         }
 575 }
 576
 577 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 578 {
 579         size_t n, l;
 580         const char *s, *t, *origin;
 581         char *d;
 582         if (p->rpath) return 0;
 583         if (!p->rpath_orig) return -1;
 584         if (!strchr(p->rpath_orig, '$')) {
 585                 p->rpath = p->rpath_orig;
 586                 return 0;
 587         }
 588         n = 0;
 589         s = p->rpath_orig;
 590         while ((t=strchr(s, '$'))) {
 591                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 592                         return -1;
 593                 s = t+1;
 594                 n++;
 595         }
 596         if (n > SSIZE_MAX/PATH_MAX) return -1;
 597
 598         if (p->kernel_mapped) {
 599                 /* $ORIGIN searches cannot be performed for the main program
 600                  * when it is suid/sgid/AT_SECURE. This is because the
 601                  * pathname is under the control of the caller of execve.
 602                  * For libraries, however, $ORIGIN can be processed safely
 603                  * since the library's pathname came from a trusted source
 604                  * (either system paths or a call to dlopen). */
 605                 if (libc.secure)
 606                         return -1;
 607                 l = readlink("/proc/self/exe", buf, buf_size);
 608                 if (l >= buf_size)
 609                         return -1;
 610                 buf[l] = 0;
 611                 origin = buf;
 612         } else {
 613                 origin = p->name;
 614         }
 615         t = strrchr(origin, '/');
 616         l = t ? t-origin : 0;
 617         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 618         if (!p->rpath) return -1;
 619
 620         d = p->rpath;
 621         s = p->rpath_orig;
 622         while ((t=strchr(s, '$'))) {
 623                 memcpy(d, s, t-s);
 624                 d += t-s;
 625                 memcpy(d, origin, l);
 626                 d += l;
 627                 /* It was determined previously that the '$' is followed
 628                  * either by "ORIGIN" or "{ORIGIN}". */
 629                 s = t + 7 + 2*(t[1]=='{');
 630         }
 631         strcpy(d, s);
 632         return 0;
 633 }
 634
 635 static void decode_dyn(struct dso *p)
 636 {
 637         size_t dyn[DYN_CNT] = {0};
 638         decode_vec(p->dynv, dyn, DYN_CNT);
 639         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 640         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 641         if (dyn[0]&(1<<DT_HASH))
 642                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 643         if (dyn[0]&(1<<DT_RPATH))
 644                 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
 645         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 646                 p->ghashtab = (void *)(p->base + *dyn);
 647         if (search_vec(p->dynv, dyn, DT_VERSYM))
 648                 p->versym = (void *)(p->base + *dyn);
 649 }
 650
 651 static struct dso *load_library(const char *name, struct dso *needed_by)
 652 {
 653         char buf[2*NAME_MAX+2];
 654         const char *pathname;
 655         unsigned char *map;
 656         struct dso *p, temp_dso = {0};
 657         int fd;
 658         struct stat st;
 659         size_t alloc_size;
 660         int n_th = 0;
 661         int is_self = 0;
 662
 663         /* Catch and block attempts to reload the implementation itself */
 664         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 665                 static const char *rp, reserved[] =
 666                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 667                 char *z = strchr(name, '.');
 668                 if (z) {
 669                         size_t l = z-name;
 670                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 671                         if (*rp) {
 672                                 if (ldd_mode) {
 673                                         /* Track which names have been resolved
 674                                          * and only report each one once. */
 675                                         static unsigned reported;
 676                                         unsigned mask = 1U<<(rp-reserved);
 677                                         if (!(reported & mask)) {
 678                                                 reported |= mask;
 679                                                 dprintf(1, "\t%s => %s (%p)\n",
 680                                                         name, ldso->name,
 681                                                         ldso->base);
 682                                         }
 683                                 }
 684                                 is_self = 1;
 685                         }
 686                 }
 687         }
 688         if (!strcmp(name, ldso->name)) is_self = 1;
 689         if (is_self) {
 690                 if (!ldso->prev) {
 691                         tail->next = ldso;
 692                         ldso->prev = tail;
 693                         tail = ldso->next ? ldso->next : ldso;
 694                 }
 695                 return ldso;
 696         }
 697         if (strchr(name, '/')) {
 698                 pathname = name;
 699                 fd = open(name, O_RDONLY|O_CLOEXEC);
 700         } else {
 701                 /* Search for the name to see if it's already loaded */
 702                 for (p=head->next; p; p=p->next) {
 703                         if (p->shortname && !strcmp(p->shortname, name)) {
 704                                 p->refcnt++;
 705                                 return p;
 706                         }
 707                 }
 708                 if (strlen(name) > NAME_MAX) return 0;
 709                 fd = -1;
 710                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 711                 for (p=needed_by; fd < 0 && p; p=p->needed_by)
 712                         if (!fixup_rpath(p, buf, sizeof buf))
 713                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 714                 if (fd < 0) {
 715                         if (!sys_path) {
 716                                 char *prefix = 0;
 717                                 size_t prefix_len;
 718                                 if (ldso->name[0]=='/') {
 719                                         char *s, *t, *z;
 720                                         for (s=t=z=ldso->name; *s; s++)
 721                                                 if (*s=='/') z=t, t=s;
 722                                         prefix_len = z-ldso->name;
 723                                         if (prefix_len < PATH_MAX)
 724                                                 prefix = ldso->name;
 725                                 }
 726                                 if (!prefix) {
 727                                         prefix = "";
 728                                         prefix_len = 0;
 729                                 }
 730                                 char etc_ldso_path[prefix_len + 1
 731                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 732                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 733                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 734                                         (int)prefix_len, prefix);
 735                                 FILE *f = fopen(etc_ldso_path, "rbe");
 736                                 if (f) {
 737                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 738                                                 free(sys_path);
 739                                                 sys_path = "";
 740                                         }
 741                                         fclose(f);
 742                                 } else if (errno != ENOENT) {
 743                                         sys_path = "";
 744                                 }
 745                         }
 746                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 747                         fd = path_open(name, sys_path, buf, sizeof buf);
 748                 }
 749                 pathname = buf;
 750         }
 751         if (fd < 0) return 0;
 752         if (fstat(fd, &st) < 0) {
 753                 close(fd);
 754                 return 0;
 755         }
 756         for (p=head->next; p; p=p->next) {
 757                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 758                         /* If this library was previously loaded with a
 759                          * pathname but a search found the same inode,
 760                          * setup its shortname so it can be found by name. */
 761                         if (!p->shortname && pathname != name)
 762                                 p->shortname = strrchr(p->name, '/')+1;
 763                         close(fd);
 764                         p->refcnt++;
 765                         return p;
 766                 }
 767         }
 768         map = noload ? 0 : map_library(fd, &temp_dso);
 769         close(fd);
 770         if (!map) return 0;
 771
 772         /* Allocate storage for the new DSO. When there is TLS, this
 773          * storage must include a reservation for all pre-existing
 774          * threads to obtain copies of both the new TLS, and an
 775          * extended DTV capable of storing an additional slot for
 776          * the newly-loaded DSO. */
 777         alloc_size = sizeof *p + strlen(pathname) + 1;
 778         if (runtime && temp_dso.tls_image) {
 779                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 780                         + sizeof(void *) * (tls_cnt+3);
 781                 n_th = libc.threads_minus_1 + 1;
 782                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 783                 else alloc_size += n_th * per_th;
 784         }
 785         p = calloc(1, alloc_size);
 786         if (!p) {
 787                 munmap(map, temp_dso.map_len);
 788                 return 0;
 789         }
 790         memcpy(p, &temp_dso, sizeof temp_dso);
 791         decode_dyn(p);
 792         p->dev = st.st_dev;
 793         p->ino = st.st_ino;
 794         p->refcnt = 1;
 795         p->needed_by = needed_by;
 796         p->name = p->buf;
 797         strcpy(p->name, pathname);
 798         /* Add a shortname only if name arg was not an explicit pathname. */
 799         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 800         if (p->tls_image) {
 801                 if (runtime && !libc.has_thread_pointer) {
 802                         munmap(map, p->map_len);
 803                         free(p);
 804                         errno = ENOSYS;
 805                         return 0;
 806                 }
 807                 p->tls_id = ++tls_cnt;
 808                 tls_align = MAXP2(tls_align, p->tls_align);
 809 #ifdef TLS_ABOVE_TP
 810                 p->tls_offset = tls_offset + ( (tls_align-1) &
 811                         -(tls_offset + (uintptr_t)p->tls_image) );
 812                 tls_offset += p->tls_size;
 813 #else
 814                 tls_offset += p->tls_size + p->tls_align - 1;
 815                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 816                         & (p->tls_align-1);
 817                 p->tls_offset = tls_offset;
 818 #endif
 819                 p->new_dtv = (void *)(-sizeof(size_t) &
 820                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 821                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 822         }
 823
 824         tail->next = p;
 825         p->prev = tail;
 826         tail = p;
 827
 828         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 829
 830         return p;
 831 }
 832
 833 static void load_deps(struct dso *p)
 834 {
 835         size_t i, ndeps=0;
 836         struct dso ***deps = &p->deps, **tmp, *dep;
 837         for (; p; p=p->next) {
 838                 for (i=0; p->dynv[i]; i+=2) {
 839                         if (p->dynv[i] != DT_NEEDED) continue;
 840                         dep = load_library(p->strings + p->dynv[i+1], p);
 841                         if (!dep) {
 842                                 error(errbuf, sizeof errbuf,
 843                                         "Error loading shared library %s: %m (needed by %s)",
 844                                         p->strings + p->dynv[i+1], p->name);
 845                                 continue;
 846                         }
 847                         if (runtime) {
 848                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 849                                 if (!tmp) longjmp(*rtld_fail, 1);
 850                                 tmp[ndeps++] = dep;
 851                                 tmp[ndeps] = 0;
 852                                 *deps = tmp;
 853                         }
 854                 }
 855         }
 856 }
 857
 858 static void load_preload(char *s)
 859 {
 860         int tmp;
 861         char *z;
 862         for (z=s; *z; s=z) {
 863                 for (   ; *s && isspace(*s); s++);
 864                 for (z=s; *z && !isspace(*z); z++);
 865                 tmp = *z;
 866                 *z = 0;
 867                 load_library(s, 0);
 868                 *z = tmp;
 869         }
 870 }
 871
 872 static void make_global(struct dso *p)
 873 {
 874         for (; p; p=p->next) p->global = 1;
 875 }
 876
 877 static void reloc_all(struct dso *p)
 878 {
 879         size_t dyn[DYN_CNT] = {0};
 880         for (; p; p=p->next) {
 881                 if (p->relocated) continue;
 882                 decode_vec(p->dynv, dyn, DYN_CNT);
 883 #ifdef NEED_ARCH_RELOCS
 884                 do_arch_relocs(p, head);
 885 #endif
 886                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 887                         2+(dyn[DT_PLTREL]==DT_RELA));
 888                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 889                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 890
 891                 if (p->relro_start != p->relro_end &&
 892                     mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) {
 893                         error(errbuf, sizeof errbuf,
 894                                 "Error relocating %s: RELRO protection failed: %m",
 895                                 p->name);
 896                 }
 897
 898                 p->relocated = 1;
 899         }
 900 }
 901
 902 static void kernel_mapped_dso(struct dso *p)
 903 {
 904         size_t min_addr = -1, max_addr = 0, cnt;
 905         Phdr *ph = p->phdr;
 906         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
 907                 if (ph->p_type == PT_DYNAMIC) {
 908                         p->dynv = (void *)(p->base + ph->p_vaddr);
 909                 } else if (ph->p_type == PT_GNU_RELRO) {
 910                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
 911                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 912                 }
 913                 if (ph->p_type != PT_LOAD) continue;
 914                 if (ph->p_vaddr < min_addr)
 915                         min_addr = ph->p_vaddr;
 916                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 917                         max_addr = ph->p_vaddr+ph->p_memsz;
 918         }
 919         min_addr &= -PAGE_SIZE;
 920         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 921         p->map = p->base + min_addr;
 922         p->map_len = max_addr - min_addr;
 923         p->kernel_mapped = 1;
 924 }
 925
 926 static void do_fini()
 927 {
 928         struct dso *p;
 929         size_t dyn[DYN_CNT] = {0};
 930         for (p=fini_head; p; p=p->fini_next) {
 931                 if (!p->constructed) continue;
 932                 decode_vec(p->dynv, dyn, DYN_CNT);
 933                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
 934                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
 935                         size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
 936                         while (n--) ((void (*)(void))*--fn)();
 937                 }
 938 #ifndef NO_LEGACY_INITFINI
 939                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
 940                         ((void (*)(void))(p->base + dyn[DT_FINI]))();
 941 #endif
 942         }
 943 }
 944
 945 static void do_init_fini(struct dso *p)
 946 {
 947         size_t dyn[DYN_CNT] = {0};
 948         int need_locking = libc.threads_minus_1;
 949         /* Allow recursive calls that arise when a library calls
 950          * dlopen from one of its constructors, but block any
 951          * other threads until all ctors have finished. */
 952         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 953         for (; p; p=p->prev) {
 954                 if (p->constructed) continue;
 955                 p->constructed = 1;
 956                 decode_vec(p->dynv, dyn, DYN_CNT);
 957                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
 958                         p->fini_next = fini_head;
 959                         fini_head = p;
 960                 }
 961 #ifndef NO_LEGACY_INITFINI
 962                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
 963                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 964 #endif
 965                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
 966                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
 967                         size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
 968                         while (n--) ((void (*)(void))*fn++)();
 969                 }
 970                 if (!need_locking && libc.threads_minus_1) {
 971                         need_locking = 1;
 972                         pthread_mutex_lock(&init_fini_lock);
 973                 }
 974         }
 975         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 976 }
 977
 978 void _dl_debug_state(void)
 979 {
 980 }
 981
 982 void __reset_tls()
 983 {
 984         pthread_t self = __pthread_self();
 985         struct dso *p;
 986         for (p=head; p; p=p->next) {
 987                 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
 988                 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
 989                 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
 990                         p->tls_size - p->tls_len);
 991                 if (p->tls_id == (size_t)self->dtv[0]) break;
 992         }
 993 }
 994
 995 void *__copy_tls(unsigned char *mem)
 996 {
 997         pthread_t td;
 998         struct dso *p;
 999
1000         void **dtv = (void *)mem;
1001         dtv[0] = (void *)tls_cnt;
1002         if (!tls_cnt) {
1003                 td = (void *)(dtv+1);
1004                 td->dtv = dtv;
1005                 return td;
1006         }
1007
1008 #ifdef TLS_ABOVE_TP
1009         mem += sizeof(void *) * (tls_cnt+1);
1010         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
1011         td = (pthread_t)mem;
1012         mem += sizeof(struct pthread);
1013
1014         for (p=head; p; p=p->next) {
1015                 if (!p->tls_id) continue;
1016                 dtv[p->tls_id] = mem + p->tls_offset;
1017                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1018         }
1019 #else
1020         mem += libc.tls_size - sizeof(struct pthread);
1021         mem -= (uintptr_t)mem & (tls_align-1);
1022         td = (pthread_t)mem;
1023
1024         for (p=head; p; p=p->next) {
1025                 if (!p->tls_id) continue;
1026                 dtv[p->tls_id] = mem - p->tls_offset;
1027                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1028         }
1029 #endif
1030         td->dtv = dtv;
1031         return td;
1032 }
1033
1034 void *__tls_get_new(size_t *v)
1035 {
1036         pthread_t self = __pthread_self();
1037
1038         /* Block signals to make accessing new TLS async-signal-safe */
1039         sigset_t set;
1040         __block_all_sigs(&set);
1041         if (v[0]<=(size_t)self->dtv[0]) {
1042                 __restore_sigs(&set);
1043                 return (char *)self->dtv[v[0]]+v[1];
1044         }
1045
1046         /* This is safe without any locks held because, if the caller
1047          * is able to request the Nth entry of the DTV, the DSO list
1048          * must be valid at least that far out and it was synchronized
1049          * at program startup or by an already-completed call to dlopen. */
1050         struct dso *p;
1051         for (p=head; p->tls_id != v[0]; p=p->next);
1052
1053         /* Get new DTV space from new DSO if needed */
1054         if (v[0] > (size_t)self->dtv[0]) {
1055                 void **newdtv = p->new_dtv +
1056                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1057                 memcpy(newdtv, self->dtv,
1058                         ((size_t)self->dtv[0]+1) * sizeof(void *));
1059                 newdtv[0] = (void *)v[0];
1060                 self->dtv = newdtv;
1061         }
1062
1063         /* Get new TLS memory from all new DSOs up to the requested one */
1064         unsigned char *mem;
1065         for (p=head; ; p=p->next) {
1066                 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1067                 mem = p->new_tls + (p->tls_size + p->tls_align)
1068                         * a_fetch_add(&p->new_tls_idx,1);
1069                 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
1070                         & (p->tls_align-1);
1071                 self->dtv[p->tls_id] = mem;
1072                 memcpy(mem, p->tls_image, p->tls_len);
1073                 if (p->tls_id == v[0]) break;
1074         }
1075         __restore_sigs(&set);
1076         return mem + v[1];
1077 }
1078
1079 static void update_tls_size()
1080 {
1081         libc.tls_size = ALIGN(
1082                 (1+tls_cnt) * sizeof(void *) +
1083                 tls_offset +
1084                 sizeof(struct pthread) +
1085                 tls_align * 2,
1086         tls_align);
1087 }
1088
1089 void *__dynlink(int argc, char **argv)
1090 {
1091         size_t aux[AUX_CNT] = {0};
1092         size_t i;
1093         Phdr *phdr;
1094         Ehdr *ehdr;
1095         static struct dso builtin_dsos[3];
1096         struct dso *const app = builtin_dsos+0;
1097         struct dso *const lib = builtin_dsos+1;
1098         struct dso *const vdso = builtin_dsos+2;
1099         char *env_preload=0;
1100         size_t vdso_base;
1101         size_t *auxv;
1102         char **envp = argv+argc+1;
1103         void *initial_tls;
1104
1105         /* Find aux vector just past environ[] */
1106         for (i=argc+1; argv[i]; i++)
1107                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
1108                         env_path = argv[i]+16;
1109                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
1110                         env_preload = argv[i]+11;
1111         auxv = (void *)(argv+i+1);
1112
1113         decode_vec(auxv, aux, AUX_CNT);
1114
1115         /* Only trust user/env if kernel says we're not suid/sgid */
1116         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1117           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
1118                 env_path = 0;
1119                 env_preload = 0;
1120                 libc.secure = 1;
1121         }
1122         libc.page_size = aux[AT_PAGESZ];
1123
1124         /* If the dynamic linker was invoked as a program itself, AT_BASE
1125          * will not be set. In that case, we assume the base address is
1126          * the start of the page containing the PHDRs; I don't know any
1127          * better approach... */
1128         if (!aux[AT_BASE]) {
1129                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
1130                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
1131         }
1132
1133         /* The dynamic linker load address is passed by the kernel
1134          * in the AUX vector, so this is easy. */
1135         lib->base = (void *)aux[AT_BASE];
1136         lib->name = lib->shortname = "libc.so";
1137         lib->global = 1;
1138         ehdr = (void *)lib->base;
1139         lib->phnum = ehdr->e_phnum;
1140         lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1141         lib->phentsize = ehdr->e_phentsize;
1142         kernel_mapped_dso(lib);
1143         decode_dyn(lib);
1144
1145         if (aux[AT_PHDR]) {
1146                 size_t interp_off = 0;
1147                 size_t tls_image = 0;
1148                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1149                 app->phdr = phdr = (void *)aux[AT_PHDR];
1150                 app->phnum = aux[AT_PHNUM];
1151                 app->phentsize = aux[AT_PHENT];
1152                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1153                         if (phdr->p_type == PT_PHDR)
1154                                 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1155                         else if (phdr->p_type == PT_INTERP)
1156                                 interp_off = (size_t)phdr->p_vaddr;
1157                         else if (phdr->p_type == PT_TLS) {
1158                                 tls_image = phdr->p_vaddr;
1159                                 app->tls_len = phdr->p_filesz;
1160                                 app->tls_size = phdr->p_memsz;
1161                                 app->tls_align = phdr->p_align;
1162                         }
1163                 }
1164                 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1165                 if (interp_off) lib->name = (char *)app->base + interp_off;
1166                 if ((aux[0] & (1UL<<AT_EXECFN))
1167                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1168                         app->name = (char *)aux[AT_EXECFN];
1169                 else
1170                         app->name = argv[0];
1171                 kernel_mapped_dso(app);
1172         } else {
1173                 int fd;
1174                 char *ldname = argv[0];
1175                 size_t l = strlen(ldname);
1176                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1177                 *argv++ = (void *)-1;
1178                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1179                         char *opt = argv[0]+2;
1180                         *argv++ = (void *)-1;
1181                         if (!*opt) {
1182                                 break;
1183                         } else if (!memcmp(opt, "list", 5)) {
1184                                 ldd_mode = 1;
1185                         } else if (!memcmp(opt, "library-path", 12)) {
1186                                 if (opt[12]=='=') env_path = opt+13;
1187                                 else if (opt[12]) *argv = 0;
1188                                 else if (*argv) env_path = *argv++;
1189                         } else if (!memcmp(opt, "preload", 7)) {
1190                                 if (opt[7]=='=') env_preload = opt+8;
1191                                 else if (opt[7]) *argv = 0;
1192                                 else if (*argv) env_preload = *argv++;
1193                         } else {
1194                                 argv[0] = 0;
1195                         }
1196                         argv[-1] = (void *)-1;
1197                 }
1198                 if (!argv[0]) {
1199                         dprintf(2, "musl libc\n"
1200                                 "Version %s\n"
1201                                 "Dynamic Program Loader\n"
1202                                 "Usage: %s [options] [--] pathname%s\n",
1203                                 __libc_get_version(), ldname,
1204                                 ldd_mode ? "" : " [args]");
1205                         _exit(1);
1206                 }
1207                 fd = open(argv[0], O_RDONLY);
1208                 if (fd < 0) {
1209                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1210                         _exit(1);
1211                 }
1212                 runtime = 1;
1213                 ehdr = (void *)map_library(fd, app);
1214                 if (!ehdr) {
1215                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1216                         _exit(1);
1217                 }
1218                 runtime = 0;
1219                 close(fd);
1220                 lib->name = ldname;
1221                 app->name = argv[0];
1222                 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1223                 /* Find the name that would have been used for the dynamic
1224                  * linker had ldd not taken its place. */
1225                 if (ldd_mode) {
1226                         for (i=0; i<app->phnum; i++) {
1227                                 if (app->phdr[i].p_type == PT_INTERP)
1228                                         lib->name = (void *)(app->base
1229                                                 + app->phdr[i].p_vaddr);
1230                         }
1231                         dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1232                 }
1233         }
1234         if (app->tls_size) {
1235                 app->tls_id = tls_cnt = 1;
1236 #ifdef TLS_ABOVE_TP
1237                 app->tls_offset = 0;
1238                 tls_offset = app->tls_size
1239                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1240                         & (app->tls_align-1) );
1241 #else
1242                 tls_offset = app->tls_offset = app->tls_size
1243                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1244                         & (app->tls_align-1) );
1245 #endif
1246                 tls_align = MAXP2(tls_align, app->tls_align);
1247         }
1248         app->global = 1;
1249         decode_dyn(app);
1250
1251         /* Attach to vdso, if provided by the kernel */
1252         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1253                 ehdr = (void *)vdso_base;
1254                 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1255                 vdso->phnum = ehdr->e_phnum;
1256                 vdso->phentsize = ehdr->e_phentsize;
1257                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1258                         if (phdr->p_type == PT_DYNAMIC)
1259                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1260                         if (phdr->p_type == PT_LOAD)
1261                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1262                 }
1263                 vdso->name = "";
1264                 vdso->shortname = "linux-gate.so.1";
1265                 vdso->global = 1;
1266                 decode_dyn(vdso);
1267                 vdso->prev = lib;
1268                 lib->next = vdso;
1269         }
1270
1271         /* Initial dso chain consists only of the app. We temporarily
1272          * append the dynamic linker/libc so we can relocate it, then
1273          * restore the initial chain in preparation for loading third
1274          * party libraries (preload/needed). */
1275         head = tail = app;
1276         ldso = lib;
1277         app->next = lib;
1278         reloc_all(lib);
1279         app->next = 0;
1280
1281         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1282
1283         /* Donate unused parts of app and library mapping to malloc */
1284         reclaim_gaps(app);
1285         reclaim_gaps(lib);
1286
1287         /* Load preload/needed libraries, add their symbols to the global
1288          * namespace, and perform all remaining relocations. The main
1289          * program must be relocated LAST since it may contain copy
1290          * relocations which depend on libraries' relocations. */
1291         if (env_preload) load_preload(env_preload);
1292         load_deps(app);
1293         make_global(app);
1294
1295 #ifndef DYNAMIC_IS_RO
1296         for (i=0; app->dynv[i]; i+=2)
1297                 if (app->dynv[i]==DT_DEBUG)
1298                         app->dynv[i+1] = (size_t)&debug;
1299 #endif
1300
1301         reloc_all(app->next);
1302         reloc_all(app);
1303
1304         update_tls_size();
1305         if (libc.tls_size > sizeof builtin_tls) {
1306                 initial_tls = calloc(libc.tls_size, 1);
1307                 if (!initial_tls) {
1308                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1309                                 argv[0], libc.tls_size);
1310                         _exit(127);
1311                 }
1312         } else {
1313                 initial_tls = builtin_tls;
1314         }
1315         if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
1316                 dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
1317                 _exit(127);
1318         }
1319         static_tls_cnt = tls_cnt;
1320
1321         if (ldso_fail) _exit(127);
1322         if (ldd_mode) _exit(0);
1323
1324         /* Switch to runtime mode: any further failures in the dynamic
1325          * linker are a reportable failure rather than a fatal startup
1326          * error. If the dynamic loader (dlopen) will not be used, free
1327          * all memory used by the dynamic linker. */
1328         runtime = 1;
1329
1330         debug.ver = 1;
1331         debug.bp = _dl_debug_state;
1332         debug.head = head;
1333         debug.base = lib->base;
1334         debug.state = 0;
1335         _dl_debug_state();
1336
1337         __init_libc(envp, argv[0]);
1338         atexit(do_fini);
1339         errno = 0;
1340         do_init_fini(tail);
1341
1342         return (void *)aux[AT_ENTRY];
1343 }
1344
1345 void *dlopen(const char *file, int mode)
1346 {
1347         struct dso *volatile p, *orig_tail, *next;
1348         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1349         size_t i;
1350         int cs;
1351         jmp_buf jb;
1352
1353         if (!file) return head;
1354
1355         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1356         pthread_rwlock_wrlock(&lock);
1357         __inhibit_ptc();
1358
1359         p = 0;
1360         orig_tls_cnt = tls_cnt;
1361         orig_tls_offset = tls_offset;
1362         orig_tls_align = tls_align;
1363         orig_tail = tail;
1364         noload = mode & RTLD_NOLOAD;
1365
1366         rtld_fail = &jb;
1367         if (setjmp(*rtld_fail)) {
1368                 /* Clean up anything new that was (partially) loaded */
1369                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1370                         if (p->deps[i]->global < 0)
1371                                 p->deps[i]->global = 0;
1372                 for (p=orig_tail->next; p; p=next) {
1373                         next = p->next;
1374                         munmap(p->map, p->map_len);
1375                         while (p->td_index) {
1376                                 void *tmp = p->td_index->next;
1377                                 free(p->td_index);
1378                                 p->td_index = tmp;
1379                         }
1380                         free(p->deps);
1381                         free(p);
1382                 }
1383                 tls_cnt = orig_tls_cnt;
1384                 tls_offset = orig_tls_offset;
1385                 tls_align = orig_tls_align;
1386                 tail = orig_tail;
1387                 tail->next = 0;
1388                 p = 0;
1389                 errflag = 1;
1390                 goto end;
1391         } else p = load_library(file, head);
1392
1393         if (!p) {
1394                 snprintf(errbuf, sizeof errbuf, noload ?
1395                         "Library %s is not already loaded" :
1396                         "Error loading shared library %s: %m",
1397                         file);
1398                 errflag = 1;
1399                 goto end;
1400         }
1401
1402         /* First load handling */
1403         if (!p->deps) {
1404                 load_deps(p);
1405                 if (p->deps) for (i=0; p->deps[i]; i++)
1406                         if (!p->deps[i]->global)
1407                                 p->deps[i]->global = -1;
1408                 if (!p->global) p->global = -1;
1409                 reloc_all(p);
1410                 if (p->deps) for (i=0; p->deps[i]; i++)
1411                         if (p->deps[i]->global < 0)
1412                                 p->deps[i]->global = 0;
1413                 if (p->global < 0) p->global = 0;
1414         }
1415
1416         if (mode & RTLD_GLOBAL) {
1417                 if (p->deps) for (i=0; p->deps[i]; i++)
1418                         p->deps[i]->global = 1;
1419                 p->global = 1;
1420         }
1421
1422         update_tls_size();
1423         _dl_debug_state();
1424         orig_tail = tail;
1425 end:
1426         __release_ptc();
1427         if (p) gencnt++;
1428         pthread_rwlock_unlock(&lock);
1429         if (p) do_init_fini(orig_tail);
1430         pthread_setcancelstate(cs, 0);
1431         return p;
1432 }
1433
1434 static int invalid_dso_handle(void *h)
1435 {
1436         struct dso *p;
1437         for (p=head; p; p=p->next) if (h==p) return 0;
1438         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1439         errflag = 1;
1440         return 1;
1441 }
1442
1443 void *__tls_get_addr(size_t *);
1444
1445 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1446 {
1447         size_t i;
1448         uint32_t h = 0, gh = 0;
1449         Sym *sym;
1450         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1451                 if (p == RTLD_DEFAULT) {
1452                         p = head;
1453                 } else if (p == RTLD_NEXT) {
1454                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1455                         if (!p) p=head;
1456                         p = p->next;
1457                 }
1458                 struct symdef def = find_sym(p, s, 0);
1459                 if (!def.sym) goto failed;
1460                 if ((def.sym->st_info&0xf) == STT_TLS)
1461                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1462                 return def.dso->base + def.sym->st_value;
1463         }
1464         if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1465                 return 0;
1466         if (p->ghashtab) {
1467                 gh = gnu_hash(s);
1468                 sym = gnu_lookup(s, gh, p);
1469         } else {
1470                 h = sysv_hash(s);
1471                 sym = sysv_lookup(s, h, p);
1472         }
1473         if (sym && (sym->st_info&0xf) == STT_TLS)
1474                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1475         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1476                 return p->base + sym->st_value;
1477         if (p->deps) for (i=0; p->deps[i]; i++) {
1478                 if (p->deps[i]->ghashtab) {
1479                         if (!gh) gh = gnu_hash(s);
1480                         sym = gnu_lookup(s, gh, p->deps[i]);
1481                 } else {
1482                         if (!h) h = sysv_hash(s);
1483                         sym = sysv_lookup(s, h, p->deps[i]);
1484                 }
1485                 if (sym && (sym->st_info&0xf) == STT_TLS)
1486                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1487                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1488                         return p->deps[i]->base + sym->st_value;
1489         }
1490 failed:
1491         errflag = 1;
1492         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1493         return 0;
1494 }
1495
1496 int __dladdr(const void *addr, Dl_info *info)
1497 {
1498         struct dso *p;
1499         Sym *sym;
1500         uint32_t nsym;
1501         char *strings;
1502         size_t i;
1503         void *best = 0;
1504         char *bestname;
1505
1506         pthread_rwlock_rdlock(&lock);
1507         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1508         pthread_rwlock_unlock(&lock);
1509
1510         if (!p) return 0;
1511
1512         sym = p->syms;
1513         strings = p->strings;
1514         if (p->hashtab) {
1515                 nsym = p->hashtab[1];
1516         } else {
1517                 uint32_t *buckets;
1518                 uint32_t *hashval;
1519                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1520                 sym += p->ghashtab[1];
1521                 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1522                         if (buckets[i] > nsym)
1523                                 nsym = buckets[i];
1524                 }
1525                 if (nsym) {
1526                         nsym -= p->ghashtab[1];
1527                         hashval = buckets + p->ghashtab[0] + nsym;
1528                         do nsym++;
1529                         while (!(*hashval++ & 1));
1530                 }
1531         }
1532
1533         for (; nsym; nsym--, sym++) {
1534                 if (sym->st_value
1535                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1536                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1537                         void *symaddr = p->base + sym->st_value;
1538                         if (symaddr > addr || symaddr < best)
1539                                 continue;
1540                         best = symaddr;
1541                         bestname = strings + sym->st_name;
1542                         if (addr == symaddr)
1543                                 break;
1544                 }
1545         }
1546
1547         if (!best) return 0;
1548
1549         info->dli_fname = p->name;
1550         info->dli_fbase = p->base;
1551         info->dli_sname = bestname;
1552         info->dli_saddr = best;
1553
1554         return 1;
1555 }
1556
1557 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1558 {
1559         void *res;
1560         pthread_rwlock_rdlock(&lock);
1561         res = do_dlsym(p, s, ra);
1562         pthread_rwlock_unlock(&lock);
1563         return res;
1564 }
1565
1566 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1567 {
1568         struct dso *current;
1569         struct dl_phdr_info info;
1570         int ret = 0;
1571         for(current = head; current;) {
1572                 info.dlpi_addr      = (uintptr_t)current->base;
1573                 info.dlpi_name      = current->name;
1574                 info.dlpi_phdr      = current->phdr;
1575                 info.dlpi_phnum     = current->phnum;
1576                 info.dlpi_adds      = gencnt;
1577                 info.dlpi_subs      = 0;
1578                 info.dlpi_tls_modid = current->tls_id;
1579                 info.dlpi_tls_data  = current->tls_image;
1580
1581                 ret = (callback)(&info, sizeof (info), data);
1582
1583                 if (ret != 0) break;
1584
1585                 pthread_rwlock_rdlock(&lock);
1586                 current = current->next;
1587                 pthread_rwlock_unlock(&lock);
1588         }
1589         return ret;
1590 }
1591 #else
1592 static int invalid_dso_handle(void *h)
1593 {
1594         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1595         errflag = 1;
1596         return 1;
1597 }
1598 void *dlopen(const char *file, int mode)
1599 {
1600         return 0;
1601 }
1602 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1603 {
1604         return 0;
1605 }
1606 int __dladdr (const void *addr, Dl_info *info)
1607 {
1608         return 0;
1609 }
1610 #endif
1611
1612 int __dlinfo(void *dso, int req, void *res)
1613 {
1614         if (invalid_dso_handle(dso)) return -1;
1615         if (req != RTLD_DI_LINKMAP) {
1616                 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1617                 errflag = 1;
1618                 return -1;
1619         }
1620         *(struct link_map **)res = dso;
1621         return 0;
1622 }
1623
1624 char *dlerror()
1625 {
1626         if (!errflag) return 0;
1627         errflag = 0;
1628         return errbuf;
1629 }
1630
1631 int dlclose(void *p)
1632 {
1633         return invalid_dso_handle(p);
1634 }