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

   1 #define _GNU_SOURCE
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6 #include <stdint.h>
   7 #include <elf.h>
   8 #include <sys/mman.h>
   9 #include <limits.h>
  10 #include <fcntl.h>
  11 #include <sys/stat.h>
  12 #include <errno.h>
  13 #include <link.h>
  14 #include <setjmp.h>
  15 #include <pthread.h>
  16 #include <ctype.h>
  17 #include <dlfcn.h>
  18 #include "pthread_impl.h"
  19 #include "libc.h"
  20
  21 static int errflag;
  22 static char errbuf[128];
  23
  24 #ifdef SHARED
  25
  26 #if ULONG_MAX == 0xffffffff
  27 typedef Elf32_Ehdr Ehdr;
  28 typedef Elf32_Phdr Phdr;
  29 typedef Elf32_Sym Sym;
  30 #define R_TYPE(x) ((x)&255)
  31 #define R_SYM(x) ((x)>>8)
  32 #else
  33 typedef Elf64_Ehdr Ehdr;
  34 typedef Elf64_Phdr Phdr;
  35 typedef Elf64_Sym Sym;
  36 #define R_TYPE(x) ((x)&0xffffffff)
  37 #define R_SYM(x) ((x)>>32)
  38 #endif
  39
  40 #define MAXP2(a,b) (-(-(a)&-(b)))
  41 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  42
  43 struct debug {
  44         int ver;
  45         void *head;
  46         void (*bp)(void);
  47         int state;
  48         void *base;
  49 };
  50
  51 struct dso {
  52         unsigned char *base;
  53         char *name;
  54         size_t *dynv;
  55         struct dso *next, *prev;
  56
  57         Phdr *phdr;
  58         int phnum;
  59         size_t phentsize;
  60         int refcnt;
  61         Sym *syms;
  62         uint32_t *hashtab;
  63         uint32_t *ghashtab;
  64         int16_t *versym;
  65         char *strings;
  66         unsigned char *map;
  67         size_t map_len;
  68         dev_t dev;
  69         ino_t ino;
  70         signed char global;
  71         char relocated;
  72         char constructed;
  73         char kernel_mapped;
  74         struct dso **deps, *needed_by;
  75         char *rpath_orig, *rpath;
  76         void *tls_image;
  77         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  78         size_t relro_start, relro_end;
  79         void **new_dtv;
  80         unsigned char *new_tls;
  81         int new_dtv_idx, new_tls_idx;
  82         struct dso *fini_next;
  83         char *shortname;
  84         char buf[];
  85 };
  86
  87 struct symdef {
  88         Sym *sym;
  89         struct dso *dso;
  90 };
  91
  92 #include "reloc.h"
  93
  94 void __init_ssp(size_t *);
  95 int __init_tp(void *);
  96 void __init_libc(char **, char *);
  97
  98 const char *__libc_get_version(void);
  99
 100 static struct dso *head, *tail, *ldso, *fini_head;
 101 static char *env_path, *sys_path;
 102 static unsigned long long gencnt;
 103 static int ssp_used;
 104 static int runtime;
 105 static int ldd_mode;
 106 static int ldso_fail;
 107 static int noload;
 108 static jmp_buf *rtld_fail;
 109 static pthread_rwlock_t lock;
 110 static struct debug debug;
 111 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
 112 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 113 static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
 114
 115 struct debug *_dl_debug_addr = &debug;
 116
 117 #define AUX_CNT 38
 118 #define DYN_CNT 34
 119
 120 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 121 {
 122         memset(a, 0, cnt*sizeof(size_t));
 123         for (; v[0]; v+=2) if (v[0]<cnt) {
 124                 a[0] |= 1ULL<<v[0];
 125                 a[v[0]] = v[1];
 126         }
 127 }
 128
 129 static int search_vec(size_t *v, size_t *r, size_t key)
 130 {
 131         for (; v[0]!=key; v+=2)
 132                 if (!v[0]) return 0;
 133         *r = v[1];
 134         return 1;
 135 }
 136
 137 static uint32_t sysv_hash(const char *s0)
 138 {
 139         const unsigned char *s = (void *)s0;
 140         uint_fast32_t h = 0;
 141         while (*s) {
 142                 h = 16*h + *s++;
 143                 h ^= h>>24 & 0xf0;
 144         }
 145         return h & 0xfffffff;
 146 }
 147
 148 static uint32_t gnu_hash(const char *s0)
 149 {
 150         const unsigned char *s = (void *)s0;
 151         uint_fast32_t h = 5381;
 152         for (; *s; s++)
 153                 h = h*33 + *s;
 154         return h;
 155 }
 156
 157 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 158 {
 159         size_t i;
 160         Sym *syms = dso->syms;
 161         uint32_t *hashtab = dso->hashtab;
 162         char *strings = dso->strings;
 163         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 164                 if ((!dso->versym || dso->versym[i] >= 0)
 165                     && (!strcmp(s, strings+syms[i].st_name)))
 166                         return syms+i;
 167         }
 168         return 0;
 169 }
 170
 171 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 172 {
 173         Sym *syms = dso->syms;
 174         char *strings = dso->strings;
 175         uint32_t *hashtab = dso->ghashtab;
 176         uint32_t nbuckets = hashtab[0];
 177         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 178         uint32_t h2;
 179         uint32_t *hashval;
 180         uint32_t i = buckets[h1 % nbuckets];
 181
 182         if (!i) return 0;
 183
 184         hashval = buckets + nbuckets + (i - hashtab[1]);
 185
 186         for (h1 |= 1; ; i++) {
 187                 h2 = *hashval++;
 188                 if ((!dso->versym || dso->versym[i] >= 0)
 189                     && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
 190                         return syms+i;
 191                 if (h2 & 1) break;
 192         }
 193
 194         return 0;
 195 }
 196
 197 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 198 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 199
 200 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 201 {
 202         uint32_t h = 0, gh = 0;
 203         struct symdef def = {0};
 204         if (dso->ghashtab) {
 205                 gh = gnu_hash(s);
 206                 if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 207         } else {
 208                 h = sysv_hash(s);
 209                 if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 210         }
 211         for (; dso; dso=dso->next) {
 212                 Sym *sym;
 213                 if (!dso->global) continue;
 214                 if (dso->ghashtab) {
 215                         if (!gh) gh = gnu_hash(s);
 216                         sym = gnu_lookup(s, gh, dso);
 217                 } else {
 218                         if (!h) h = sysv_hash(s);
 219                         sym = sysv_lookup(s, h, dso);
 220                 }
 221                 if (!sym) continue;
 222                 if (!sym->st_shndx)
 223                         if (need_def || (sym->st_info&0xf) == STT_TLS)
 224                                 continue;
 225                 if (!sym->st_value)
 226                         if ((sym->st_info&0xf) != STT_TLS)
 227                                 continue;
 228                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 229                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 230
 231                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 232                 def.sym = sym;
 233                 def.dso = dso;
 234                 if (sym->st_info>>4 == STB_GLOBAL) break;
 235         }
 236         return def;
 237 }
 238
 239 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 240 {
 241         unsigned char *base = dso->base;
 242         Sym *syms = dso->syms;
 243         char *strings = dso->strings;
 244         Sym *sym;
 245         const char *name;
 246         void *ctx;
 247         int type;
 248         int sym_index;
 249         struct symdef def;
 250
 251         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 252                 type = R_TYPE(rel[1]);
 253                 sym_index = R_SYM(rel[1]);
 254                 if (sym_index) {
 255                         sym = syms + sym_index;
 256                         name = strings + sym->st_name;
 257                         ctx = IS_COPY(type) ? head->next : head;
 258                         def = find_sym(ctx, name, IS_PLT(type));
 259                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 260                             || sym->st_info>>4 != STB_WEAK)) {
 261                                 snprintf(errbuf, sizeof errbuf,
 262                                         "Error relocating %s: %s: symbol not found",
 263                                         dso->name, name);
 264                                 if (runtime) longjmp(*rtld_fail, 1);
 265                                 dprintf(2, "%s\n", errbuf);
 266                                 ldso_fail = 1;
 267                                 continue;
 268                         }
 269                 } else {
 270                         sym = 0;
 271                         def.sym = 0;
 272                         def.dso = 0;
 273                 }
 274                 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
 275                         stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
 276                         def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
 277         }
 278 }
 279
 280 /* A huge hack: to make up for the wastefulness of shared libraries
 281  * needing at least a page of dirty memory even if they have no global
 282  * data, we reclaim the gaps at the beginning and end of writable maps
 283  * and "donate" them to the heap by setting up minimal malloc
 284  * structures and then freeing them. */
 285
 286 static void reclaim(struct dso *dso, size_t start, size_t end)
 287 {
 288         size_t *a, *z;
 289         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 290         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 291         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 292         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 293         if (start>end || end-start < 4*sizeof(size_t)) return;
 294         a = (size_t *)(dso->base + start);
 295         z = (size_t *)(dso->base + end);
 296         a[-2] = 1;
 297         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 298         z[1] = 1;
 299         free(a);
 300 }
 301
 302 static void reclaim_gaps(struct dso *dso)
 303 {
 304         Phdr *ph = dso->phdr;
 305         size_t phcnt = dso->phnum;
 306
 307         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 308                 if (ph->p_type!=PT_LOAD) continue;
 309                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 310                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 311                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 312                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 313         }
 314 }
 315
 316 static void *map_library(int fd, struct dso *dso)
 317 {
 318         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 319         void *allocated_buf=0;
 320         size_t phsize;
 321         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 322         size_t this_min, this_max;
 323         off_t off_start;
 324         Ehdr *eh;
 325         Phdr *ph, *ph0;
 326         unsigned prot;
 327         unsigned char *map=MAP_FAILED, *base;
 328         size_t dyn=0;
 329         size_t tls_image=0;
 330         size_t i;
 331
 332         ssize_t l = read(fd, buf, sizeof buf);
 333         eh = buf;
 334         if (l<0) return 0;
 335         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 336                 goto noexec;
 337         phsize = eh->e_phentsize * eh->e_phnum;
 338         if (phsize > sizeof buf - sizeof *eh) {
 339                 allocated_buf = malloc(phsize);
 340                 if (!allocated_buf) return 0;
 341                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 342                 if (l < 0) goto error;
 343                 if (l != phsize) goto noexec;
 344                 ph = ph0 = allocated_buf;
 345         } else if (eh->e_phoff + phsize > l) {
 346                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 347                 if (l < 0) goto error;
 348                 if (l != phsize) goto noexec;
 349                 ph = ph0 = (void *)(buf + 1);
 350         } else {
 351                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 352         }
 353         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 354                 if (ph->p_type == PT_DYNAMIC) {
 355                         dyn = ph->p_vaddr;
 356                 } else if (ph->p_type == PT_TLS) {
 357                         tls_image = ph->p_vaddr;
 358                         dso->tls_align = ph->p_align;
 359                         dso->tls_len = ph->p_filesz;
 360                         dso->tls_size = ph->p_memsz;
 361                 } else if (ph->p_type == PT_GNU_RELRO) {
 362                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 363                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 364                 }
 365                 if (ph->p_type != PT_LOAD) continue;
 366                 if (ph->p_vaddr < addr_min) {
 367                         addr_min = ph->p_vaddr;
 368                         off_start = ph->p_offset;
 369                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 370                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 371                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 372                 }
 373                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 374                         addr_max = ph->p_vaddr+ph->p_memsz;
 375                 }
 376         }
 377         if (!dyn) goto noexec;
 378         addr_max += PAGE_SIZE-1;
 379         addr_max &= -PAGE_SIZE;
 380         addr_min &= -PAGE_SIZE;
 381         off_start &= -PAGE_SIZE;
 382         map_len = addr_max - addr_min + off_start;
 383         /* The first time, we map too much, possibly even more than
 384          * the length of the file. This is okay because we will not
 385          * use the invalid part; we just need to reserve the right
 386          * amount of virtual address space to map over later. */
 387         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 388         if (map==MAP_FAILED) goto error;
 389         /* If the loaded file is not relocatable and the requested address is
 390          * not available, then the load operation must fail. */
 391         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 392                 errno = EBUSY;
 393                 goto error;
 394         }
 395         base = map - addr_min;
 396         dso->phdr = 0;
 397         dso->phnum = 0;
 398         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 399                 if (ph->p_type != PT_LOAD) continue;
 400                 /* Check if the programs headers are in this load segment, and
 401                  * if so, record the address for use by dl_iterate_phdr. */
 402                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 403                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 404                         dso->phdr = (void *)(base + ph->p_vaddr
 405                                 + (eh->e_phoff-ph->p_offset));
 406                         dso->phnum = eh->e_phnum;
 407                         dso->phentsize = eh->e_phentsize;
 408                 }
 409                 /* Reuse the existing mapping for the lowest-address LOAD */
 410                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 411                 this_min = ph->p_vaddr & -PAGE_SIZE;
 412                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 413                 off_start = ph->p_offset & -PAGE_SIZE;
 414                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 415                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 416                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 417                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 418                         goto error;
 419                 if (ph->p_memsz > ph->p_filesz) {
 420                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 421                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 422                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 423                         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)
 424                                 goto error;
 425                 }
 426         }
 427         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 428                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 429                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 430                                 goto error;
 431                         break;
 432                 }
 433         dso->map = map;
 434         dso->map_len = map_len;
 435         dso->base = base;
 436         dso->dynv = (void *)(base+dyn);
 437         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 438         if (!runtime) reclaim_gaps(dso);
 439         free(allocated_buf);
 440         return map;
 441 noexec:
 442         errno = ENOEXEC;
 443 error:
 444         if (map!=MAP_FAILED) munmap(map, map_len);
 445         free(allocated_buf);
 446         return 0;
 447 }
 448
 449 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 450 {
 451         size_t l;
 452         int fd;
 453         for (;;) {
 454                 s += strspn(s, ":\n");
 455                 l = strcspn(s, ":\n");
 456                 if (l-1 >= INT_MAX) return -1;
 457                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
 458                         continue;
 459                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 460                 s += l;
 461         }
 462 }
 463
 464 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 465 {
 466         size_t n, l;
 467         const char *s, *t, *origin;
 468         char *d;
 469         if (p->rpath) return 0;
 470         if (!p->rpath_orig) return -1;
 471         if (!strchr(p->rpath_orig, '$')) {
 472                 p->rpath = p->rpath_orig;
 473                 return 0;
 474         }
 475         n = 0;
 476         s = p->rpath_orig;
 477         while ((t=strchr(s, '$'))) {
 478                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 479                         return -1;
 480                 s = t+1;
 481                 n++;
 482         }
 483         if (n > SSIZE_MAX/PATH_MAX) return -1;
 484
 485         if (p->kernel_mapped) {
 486                 /* $ORIGIN searches cannot be performed for the main program
 487                  * when it is suid/sgid/AT_SECURE. This is because the
 488                  * pathname is under the control of the caller of execve.
 489                  * For libraries, however, $ORIGIN can be processed safely
 490                  * since the library's pathname came from a trusted source
 491                  * (either system paths or a call to dlopen). */
 492                 if (libc.secure)
 493                         return -1;
 494                 l = readlink("/proc/self/exe", buf, buf_size);
 495                 if (l >= buf_size)
 496                         return -1;
 497                 buf[l] = 0;
 498                 origin = buf;
 499         } else {
 500                 origin = p->name;
 501         }
 502         t = strrchr(origin, '/');
 503         l = t ? t-origin : 0;
 504         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 505         if (!p->rpath) return -1;
 506
 507         d = p->rpath;
 508         s = p->rpath_orig;
 509         while ((t=strchr(s, '$'))) {
 510                 memcpy(d, s, t-s);
 511                 d += t-s;
 512                 memcpy(d, origin, l);
 513                 d += l;
 514                 /* It was determined previously that the '$' is followed
 515                  * either by "ORIGIN" or "{ORIGIN}". */
 516                 s = t + 7 + 2*(t[1]=='{');
 517         }
 518         strcpy(d, s);
 519         return 0;
 520 }
 521
 522 static void decode_dyn(struct dso *p)
 523 {
 524         size_t dyn[DYN_CNT] = {0};
 525         decode_vec(p->dynv, dyn, DYN_CNT);
 526         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 527         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 528         if (dyn[0]&(1<<DT_HASH))
 529                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 530         if (dyn[0]&(1<<DT_RPATH))
 531                 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
 532         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 533                 p->ghashtab = (void *)(p->base + *dyn);
 534         if (search_vec(p->dynv, dyn, DT_VERSYM))
 535                 p->versym = (void *)(p->base + *dyn);
 536 }
 537
 538 static struct dso *load_library(const char *name, struct dso *needed_by)
 539 {
 540         char buf[2*NAME_MAX+2];
 541         const char *pathname;
 542         unsigned char *map;
 543         struct dso *p, temp_dso = {0};
 544         int fd;
 545         struct stat st;
 546         size_t alloc_size;
 547         int n_th = 0;
 548         int is_self = 0;
 549
 550         /* Catch and block attempts to reload the implementation itself */
 551         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 552                 static const char *rp, reserved[] =
 553                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 554                 char *z = strchr(name, '.');
 555                 if (z) {
 556                         size_t l = z-name;
 557                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 558                         if (*rp) {
 559                                 if (ldd_mode) {
 560                                         /* Track which names have been resolved
 561                                          * and only report each one once. */
 562                                         static unsigned reported;
 563                                         unsigned mask = 1U<<(rp-reserved);
 564                                         if (!(reported & mask)) {
 565                                                 reported |= mask;
 566                                                 dprintf(1, "\t%s => %s (%p)\n",
 567                                                         name, ldso->name,
 568                                                         ldso->base);
 569                                         }
 570                                 }
 571                                 is_self = 1;
 572                         }
 573                 }
 574         }
 575         if (!strcmp(name, ldso->name)) is_self = 1;
 576         if (is_self) {
 577                 if (!ldso->prev) {
 578                         tail->next = ldso;
 579                         ldso->prev = tail;
 580                         tail = ldso->next ? ldso->next : ldso;
 581                 }
 582                 return ldso;
 583         }
 584         if (strchr(name, '/')) {
 585                 pathname = name;
 586                 fd = open(name, O_RDONLY|O_CLOEXEC);
 587         } else {
 588                 /* Search for the name to see if it's already loaded */
 589                 for (p=head->next; p; p=p->next) {
 590                         if (p->shortname && !strcmp(p->shortname, name)) {
 591                                 p->refcnt++;
 592                                 return p;
 593                         }
 594                 }
 595                 if (strlen(name) > NAME_MAX) return 0;
 596                 fd = -1;
 597                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 598                 for (p=needed_by; fd < 0 && p; p=p->needed_by)
 599                         if (!fixup_rpath(p, buf, sizeof buf))
 600                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 601                 if (fd < 0) {
 602                         if (!sys_path) {
 603                                 char *prefix = 0;
 604                                 size_t prefix_len;
 605                                 if (ldso->name[0]=='/') {
 606                                         char *s, *t, *z;
 607                                         for (s=t=z=ldso->name; *s; s++)
 608                                                 if (*s=='/') z=t, t=s;
 609                                         prefix_len = z-ldso->name;
 610                                         if (prefix_len < PATH_MAX)
 611                                                 prefix = ldso->name;
 612                                 }
 613                                 if (!prefix) {
 614                                         prefix = "";
 615                                         prefix_len = 0;
 616                                 }
 617                                 char etc_ldso_path[prefix_len + 1
 618                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 619                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 620                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 621                                         (int)prefix_len, prefix);
 622                                 FILE *f = fopen(etc_ldso_path, "rbe");
 623                                 if (f) {
 624                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 625                                                 free(sys_path);
 626                                                 sys_path = "";
 627                                         }
 628                                         fclose(f);
 629                                 } else if (errno != ENOENT) {
 630                                         sys_path = "";
 631                                 }
 632                         }
 633                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 634                         fd = path_open(name, sys_path, buf, sizeof buf);
 635                 }
 636                 pathname = buf;
 637         }
 638         if (fd < 0) return 0;
 639         if (fstat(fd, &st) < 0) {
 640                 close(fd);
 641                 return 0;
 642         }
 643         for (p=head->next; p; p=p->next) {
 644                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 645                         /* If this library was previously loaded with a
 646                          * pathname but a search found the same inode,
 647                          * setup its shortname so it can be found by name. */
 648                         if (!p->shortname && pathname != name)
 649                                 p->shortname = strrchr(p->name, '/')+1;
 650                         close(fd);
 651                         p->refcnt++;
 652                         return p;
 653                 }
 654         }
 655         map = noload ? 0 : map_library(fd, &temp_dso);
 656         close(fd);
 657         if (!map) return 0;
 658
 659         /* Allocate storage for the new DSO. When there is TLS, this
 660          * storage must include a reservation for all pre-existing
 661          * threads to obtain copies of both the new TLS, and an
 662          * extended DTV capable of storing an additional slot for
 663          * the newly-loaded DSO. */
 664         alloc_size = sizeof *p + strlen(pathname) + 1;
 665         if (runtime && temp_dso.tls_image) {
 666                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 667                         + sizeof(void *) * (tls_cnt+3);
 668                 n_th = libc.threads_minus_1 + 1;
 669                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 670                 else alloc_size += n_th * per_th;
 671         }
 672         p = calloc(1, alloc_size);
 673         if (!p) {
 674                 munmap(map, temp_dso.map_len);
 675                 return 0;
 676         }
 677         memcpy(p, &temp_dso, sizeof temp_dso);
 678         decode_dyn(p);
 679         p->dev = st.st_dev;
 680         p->ino = st.st_ino;
 681         p->refcnt = 1;
 682         p->needed_by = needed_by;
 683         p->name = p->buf;
 684         strcpy(p->name, pathname);
 685         /* Add a shortname only if name arg was not an explicit pathname. */
 686         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 687         if (p->tls_image) {
 688                 if (runtime && !libc.has_thread_pointer) {
 689                         munmap(map, p->map_len);
 690                         free(p);
 691                         errno = ENOSYS;
 692                         return 0;
 693                 }
 694                 p->tls_id = ++tls_cnt;
 695                 tls_align = MAXP2(tls_align, p->tls_align);
 696 #ifdef TLS_ABOVE_TP
 697                 p->tls_offset = tls_offset + ( (tls_align-1) &
 698                         -(tls_offset + (uintptr_t)p->tls_image) );
 699                 tls_offset += p->tls_size;
 700 #else
 701                 tls_offset += p->tls_size + p->tls_align - 1;
 702                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 703                         & (p->tls_align-1);
 704                 p->tls_offset = tls_offset;
 705 #endif
 706                 p->new_dtv = (void *)(-sizeof(size_t) &
 707                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 708                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 709         }
 710
 711         tail->next = p;
 712         p->prev = tail;
 713         tail = p;
 714
 715         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 716
 717         return p;
 718 }
 719
 720 static void load_deps(struct dso *p)
 721 {
 722         size_t i, ndeps=0;
 723         struct dso ***deps = &p->deps, **tmp, *dep;
 724         for (; p; p=p->next) {
 725                 for (i=0; p->dynv[i]; i+=2) {
 726                         if (p->dynv[i] != DT_NEEDED) continue;
 727                         dep = load_library(p->strings + p->dynv[i+1], p);
 728                         if (!dep) {
 729                                 snprintf(errbuf, sizeof errbuf,
 730                                         "Error loading shared library %s: %m (needed by %s)",
 731                                         p->strings + p->dynv[i+1], p->name);
 732                                 if (runtime) longjmp(*rtld_fail, 1);
 733                                 dprintf(2, "%s\n", errbuf);
 734                                 ldso_fail = 1;
 735                                 continue;
 736                         }
 737                         if (runtime) {
 738                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 739                                 if (!tmp) longjmp(*rtld_fail, 1);
 740                                 tmp[ndeps++] = dep;
 741                                 tmp[ndeps] = 0;
 742                                 *deps = tmp;
 743                         }
 744                 }
 745         }
 746 }
 747
 748 static void load_preload(char *s)
 749 {
 750         int tmp;
 751         char *z;
 752         for (z=s; *z; s=z) {
 753                 for (   ; *s && isspace(*s); s++);
 754                 for (z=s; *z && !isspace(*z); z++);
 755                 tmp = *z;
 756                 *z = 0;
 757                 load_library(s, 0);
 758                 *z = tmp;
 759         }
 760 }
 761
 762 static void make_global(struct dso *p)
 763 {
 764         for (; p; p=p->next) p->global = 1;
 765 }
 766
 767 static void reloc_all(struct dso *p)
 768 {
 769         size_t dyn[DYN_CNT] = {0};
 770         for (; p; p=p->next) {
 771                 if (p->relocated) continue;
 772                 decode_vec(p->dynv, dyn, DYN_CNT);
 773 #ifdef NEED_ARCH_RELOCS
 774                 do_arch_relocs(p, head);
 775 #endif
 776                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 777                         2+(dyn[DT_PLTREL]==DT_RELA));
 778                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 779                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 780
 781                 if (p->relro_start != p->relro_end &&
 782                     mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) {
 783                         snprintf(errbuf, sizeof errbuf,
 784                                 "Error relocating %s: RELRO protection failed: %m",
 785                                 p->name);
 786                         if (runtime) longjmp(*rtld_fail, 1);
 787                         dprintf(2, "%s\n", errbuf);
 788                         ldso_fail = 1;
 789                 }
 790
 791                 p->relocated = 1;
 792         }
 793 }
 794
 795 static void kernel_mapped_dso(struct dso *p)
 796 {
 797         size_t min_addr = -1, max_addr = 0, cnt;
 798         Phdr *ph = p->phdr;
 799         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
 800                 if (ph->p_type == PT_DYNAMIC) {
 801                         p->dynv = (void *)(p->base + ph->p_vaddr);
 802                 } else if (ph->p_type == PT_GNU_RELRO) {
 803                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
 804                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 805                 }
 806                 if (ph->p_type != PT_LOAD) continue;
 807                 if (ph->p_vaddr < min_addr)
 808                         min_addr = ph->p_vaddr;
 809                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 810                         max_addr = ph->p_vaddr+ph->p_memsz;
 811         }
 812         min_addr &= -PAGE_SIZE;
 813         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 814         p->map = p->base + min_addr;
 815         p->map_len = max_addr - min_addr;
 816         p->kernel_mapped = 1;
 817 }
 818
 819 static void do_fini()
 820 {
 821         struct dso *p;
 822         size_t dyn[DYN_CNT] = {0};
 823         for (p=fini_head; p; p=p->fini_next) {
 824                 if (!p->constructed) continue;
 825                 decode_vec(p->dynv, dyn, DYN_CNT);
 826                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
 827                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
 828                         size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
 829                         while (n--) ((void (*)(void))*--fn)();
 830                 }
 831 #ifndef NO_LEGACY_INITFINI
 832                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
 833                         ((void (*)(void))(p->base + dyn[DT_FINI]))();
 834 #endif
 835         }
 836 }
 837
 838 static void do_init_fini(struct dso *p)
 839 {
 840         size_t dyn[DYN_CNT] = {0};
 841         int need_locking = libc.threads_minus_1;
 842         /* Allow recursive calls that arise when a library calls
 843          * dlopen from one of its constructors, but block any
 844          * other threads until all ctors have finished. */
 845         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 846         for (; p; p=p->prev) {
 847                 if (p->constructed) continue;
 848                 p->constructed = 1;
 849                 decode_vec(p->dynv, dyn, DYN_CNT);
 850                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
 851                         p->fini_next = fini_head;
 852                         fini_head = p;
 853                 }
 854 #ifndef NO_LEGACY_INITFINI
 855                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
 856                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 857 #endif
 858                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
 859                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
 860                         size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
 861                         while (n--) ((void (*)(void))*fn++)();
 862                 }
 863                 if (!need_locking && libc.threads_minus_1) {
 864                         need_locking = 1;
 865                         pthread_mutex_lock(&init_fini_lock);
 866                 }
 867         }
 868         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 869 }
 870
 871 void _dl_debug_state(void)
 872 {
 873 }
 874
 875 void __reset_tls()
 876 {
 877         pthread_t self = __pthread_self();
 878         struct dso *p;
 879         for (p=head; p; p=p->next) {
 880                 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
 881                 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
 882                 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
 883                         p->tls_size - p->tls_len);
 884                 if (p->tls_id == (size_t)self->dtv[0]) break;
 885         }
 886 }
 887
 888 void *__copy_tls(unsigned char *mem)
 889 {
 890         pthread_t td;
 891         struct dso *p;
 892
 893         void **dtv = (void *)mem;
 894         dtv[0] = (void *)tls_cnt;
 895         if (!tls_cnt) {
 896                 td = (void *)(dtv+1);
 897                 td->dtv = dtv;
 898                 return td;
 899         }
 900
 901 #ifdef TLS_ABOVE_TP
 902         mem += sizeof(void *) * (tls_cnt+1);
 903         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
 904         td = (pthread_t)mem;
 905         mem += sizeof(struct pthread);
 906
 907         for (p=head; p; p=p->next) {
 908                 if (!p->tls_id) continue;
 909                 dtv[p->tls_id] = mem + p->tls_offset;
 910                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 911         }
 912 #else
 913         mem += libc.tls_size - sizeof(struct pthread);
 914         mem -= (uintptr_t)mem & (tls_align-1);
 915         td = (pthread_t)mem;
 916
 917         for (p=head; p; p=p->next) {
 918                 if (!p->tls_id) continue;
 919                 dtv[p->tls_id] = mem - p->tls_offset;
 920                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 921         }
 922 #endif
 923         td->dtv = dtv;
 924         return td;
 925 }
 926
 927 void *__tls_get_addr(size_t *v)
 928 {
 929         pthread_t self = __pthread_self();
 930         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
 931                 return (char *)self->dtv[v[0]]+v[1];
 932
 933         /* Block signals to make accessing new TLS async-signal-safe */
 934         sigset_t set;
 935         pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
 936         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
 937                 pthread_sigmask(SIG_SETMASK, &set, 0);
 938                 return (char *)self->dtv[v[0]]+v[1];
 939         }
 940
 941         /* This is safe without any locks held because, if the caller
 942          * is able to request the Nth entry of the DTV, the DSO list
 943          * must be valid at least that far out and it was synchronized
 944          * at program startup or by an already-completed call to dlopen. */
 945         struct dso *p;
 946         for (p=head; p->tls_id != v[0]; p=p->next);
 947
 948         /* Get new DTV space from new DSO if needed */
 949         if (v[0] > (size_t)self->dtv[0]) {
 950                 void **newdtv = p->new_dtv +
 951                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
 952                 memcpy(newdtv, self->dtv,
 953                         ((size_t)self->dtv[0]+1) * sizeof(void *));
 954                 newdtv[0] = (void *)v[0];
 955                 self->dtv = newdtv;
 956         }
 957
 958         /* Get new TLS memory from new DSO */
 959         unsigned char *mem = p->new_tls +
 960                 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
 961         mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
 962         self->dtv[v[0]] = mem;
 963         memcpy(mem, p->tls_image, p->tls_len);
 964         pthread_sigmask(SIG_SETMASK, &set, 0);
 965         return mem + v[1];
 966 }
 967
 968 static void update_tls_size()
 969 {
 970         libc.tls_size = ALIGN(
 971                 (1+tls_cnt) * sizeof(void *) +
 972                 tls_offset +
 973                 sizeof(struct pthread) +
 974                 tls_align * 2,
 975         tls_align);
 976 }
 977
 978 void *__dynlink(int argc, char **argv)
 979 {
 980         size_t aux[AUX_CNT] = {0};
 981         size_t i;
 982         Phdr *phdr;
 983         Ehdr *ehdr;
 984         static struct dso builtin_dsos[3];
 985         struct dso *const app = builtin_dsos+0;
 986         struct dso *const lib = builtin_dsos+1;
 987         struct dso *const vdso = builtin_dsos+2;
 988         char *env_preload=0;
 989         size_t vdso_base;
 990         size_t *auxv;
 991         char **envp = argv+argc+1;
 992         void *initial_tls;
 993
 994         /* Find aux vector just past environ[] */
 995         for (i=argc+1; argv[i]; i++)
 996                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
 997                         env_path = argv[i]+16;
 998                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
 999                         env_preload = argv[i]+11;
1000         auxv = (void *)(argv+i+1);
1001
1002         decode_vec(auxv, aux, AUX_CNT);
1003
1004         /* Only trust user/env if kernel says we're not suid/sgid */
1005         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1006           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
1007                 env_path = 0;
1008                 env_preload = 0;
1009                 libc.secure = 1;
1010         }
1011         libc.page_size = aux[AT_PAGESZ];
1012
1013         /* If the dynamic linker was invoked as a program itself, AT_BASE
1014          * will not be set. In that case, we assume the base address is
1015          * the start of the page containing the PHDRs; I don't know any
1016          * better approach... */
1017         if (!aux[AT_BASE]) {
1018                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
1019                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
1020         }
1021
1022         /* The dynamic linker load address is passed by the kernel
1023          * in the AUX vector, so this is easy. */
1024         lib->base = (void *)aux[AT_BASE];
1025         lib->name = lib->shortname = "libc.so";
1026         lib->global = 1;
1027         ehdr = (void *)lib->base;
1028         lib->phnum = ehdr->e_phnum;
1029         lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1030         lib->phentsize = ehdr->e_phentsize;
1031         kernel_mapped_dso(lib);
1032         decode_dyn(lib);
1033
1034         if (aux[AT_PHDR]) {
1035                 size_t interp_off = 0;
1036                 size_t tls_image = 0;
1037                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1038                 app->phdr = phdr = (void *)aux[AT_PHDR];
1039                 app->phnum = aux[AT_PHNUM];
1040                 app->phentsize = aux[AT_PHENT];
1041                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1042                         if (phdr->p_type == PT_PHDR)
1043                                 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1044                         else if (phdr->p_type == PT_INTERP)
1045                                 interp_off = (size_t)phdr->p_vaddr;
1046                         else if (phdr->p_type == PT_TLS) {
1047                                 tls_image = phdr->p_vaddr;
1048                                 app->tls_len = phdr->p_filesz;
1049                                 app->tls_size = phdr->p_memsz;
1050                                 app->tls_align = phdr->p_align;
1051                         }
1052                 }
1053                 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1054                 if (interp_off) lib->name = (char *)app->base + interp_off;
1055                 if ((aux[0] & (1UL<<AT_EXECFN))
1056                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1057                         app->name = (char *)aux[AT_EXECFN];
1058                 else
1059                         app->name = argv[0];
1060                 kernel_mapped_dso(app);
1061         } else {
1062                 int fd;
1063                 char *ldname = argv[0];
1064                 size_t l = strlen(ldname);
1065                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1066                 *argv++ = (void *)-1;
1067                 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
1068                 if (!argv[0]) {
1069                         dprintf(2, "musl libc\n"
1070                                 "Version %s\n"
1071                                 "Dynamic Program Loader\n"
1072                                 "Usage: %s [--] pathname%s\n",
1073                                 __libc_get_version(), ldname,
1074                                 ldd_mode ? "" : " [args]");
1075                         _exit(1);
1076                 }
1077                 fd = open(argv[0], O_RDONLY);
1078                 if (fd < 0) {
1079                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1080                         _exit(1);
1081                 }
1082                 runtime = 1;
1083                 ehdr = (void *)map_library(fd, app);
1084                 if (!ehdr) {
1085                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1086                         _exit(1);
1087                 }
1088                 runtime = 0;
1089                 close(fd);
1090                 lib->name = ldname;
1091                 app->name = argv[0];
1092                 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1093                 /* Find the name that would have been used for the dynamic
1094                  * linker had ldd not taken its place. */
1095                 if (ldd_mode) {
1096                         for (i=0; i<app->phnum; i++) {
1097                                 if (app->phdr[i].p_type == PT_INTERP)
1098                                         lib->name = (void *)(app->base
1099                                                 + app->phdr[i].p_vaddr);
1100                         }
1101                         dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1102                 }
1103         }
1104         if (app->tls_size) {
1105                 app->tls_id = tls_cnt = 1;
1106 #ifdef TLS_ABOVE_TP
1107                 app->tls_offset = 0;
1108                 tls_offset = app->tls_size
1109                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1110                         & (app->tls_align-1) );
1111 #else
1112                 tls_offset = app->tls_offset = app->tls_size
1113                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1114                         & (app->tls_align-1) );
1115 #endif
1116                 tls_align = MAXP2(tls_align, app->tls_align);
1117         }
1118         app->global = 1;
1119         decode_dyn(app);
1120
1121         /* Attach to vdso, if provided by the kernel */
1122         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1123                 ehdr = (void *)vdso_base;
1124                 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1125                 vdso->phnum = ehdr->e_phnum;
1126                 vdso->phentsize = ehdr->e_phentsize;
1127                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1128                         if (phdr->p_type == PT_DYNAMIC)
1129                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1130                         if (phdr->p_type == PT_LOAD)
1131                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1132                 }
1133                 vdso->name = "";
1134                 vdso->shortname = "linux-gate.so.1";
1135                 vdso->global = 1;
1136                 decode_dyn(vdso);
1137                 vdso->prev = lib;
1138                 lib->next = vdso;
1139         }
1140
1141         /* Initial dso chain consists only of the app. We temporarily
1142          * append the dynamic linker/libc so we can relocate it, then
1143          * restore the initial chain in preparation for loading third
1144          * party libraries (preload/needed). */
1145         head = tail = app;
1146         ldso = lib;
1147         app->next = lib;
1148         reloc_all(lib);
1149         app->next = 0;
1150
1151         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1152
1153         /* Donate unused parts of app and library mapping to malloc */
1154         reclaim_gaps(app);
1155         reclaim_gaps(lib);
1156
1157         /* Load preload/needed libraries, add their symbols to the global
1158          * namespace, and perform all remaining relocations. The main
1159          * program must be relocated LAST since it may contain copy
1160          * relocations which depend on libraries' relocations. */
1161         if (env_preload) load_preload(env_preload);
1162         load_deps(app);
1163         make_global(app);
1164
1165 #ifndef DYNAMIC_IS_RO
1166         for (i=0; app->dynv[i]; i+=2)
1167                 if (app->dynv[i]==DT_DEBUG)
1168                         app->dynv[i+1] = (size_t)&debug;
1169 #endif
1170
1171         reloc_all(app->next);
1172         reloc_all(app);
1173
1174         update_tls_size();
1175         if (libc.tls_size > sizeof builtin_tls) {
1176                 initial_tls = calloc(libc.tls_size, 1);
1177                 if (!initial_tls) {
1178                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1179                                 argv[0], libc.tls_size);
1180                         _exit(127);
1181                 }
1182         } else {
1183                 initial_tls = builtin_tls;
1184         }
1185         if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
1186                 dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
1187                 _exit(127);
1188         }
1189
1190         if (ldso_fail) _exit(127);
1191         if (ldd_mode) _exit(0);
1192
1193         /* Switch to runtime mode: any further failures in the dynamic
1194          * linker are a reportable failure rather than a fatal startup
1195          * error. If the dynamic loader (dlopen) will not be used, free
1196          * all memory used by the dynamic linker. */
1197         runtime = 1;
1198
1199         debug.ver = 1;
1200         debug.bp = _dl_debug_state;
1201         debug.head = head;
1202         debug.base = lib->base;
1203         debug.state = 0;
1204         _dl_debug_state();
1205
1206         if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1207         __init_libc(envp, argv[0]);
1208         atexit(do_fini);
1209         errno = 0;
1210         do_init_fini(tail);
1211
1212         return (void *)aux[AT_ENTRY];
1213 }
1214
1215 void *dlopen(const char *file, int mode)
1216 {
1217         struct dso *volatile p, *orig_tail, *next;
1218         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1219         size_t i;
1220         int cs;
1221         jmp_buf jb;
1222
1223         if (!file) return head;
1224
1225         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1226         pthread_rwlock_wrlock(&lock);
1227         __inhibit_ptc();
1228
1229         p = 0;
1230         orig_tls_cnt = tls_cnt;
1231         orig_tls_offset = tls_offset;
1232         orig_tls_align = tls_align;
1233         orig_tail = tail;
1234         noload = mode & RTLD_NOLOAD;
1235
1236         rtld_fail = &jb;
1237         if (setjmp(*rtld_fail)) {
1238                 /* Clean up anything new that was (partially) loaded */
1239                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1240                         if (p->deps[i]->global < 0)
1241                                 p->deps[i]->global = 0;
1242                 for (p=orig_tail->next; p; p=next) {
1243                         next = p->next;
1244                         munmap(p->map, p->map_len);
1245                         free(p->deps);
1246                         free(p);
1247                 }
1248                 tls_cnt = orig_tls_cnt;
1249                 tls_offset = orig_tls_offset;
1250                 tls_align = orig_tls_align;
1251                 tail = orig_tail;
1252                 tail->next = 0;
1253                 p = 0;
1254                 errflag = 1;
1255                 goto end;
1256         } else p = load_library(file, head);
1257
1258         if (!p) {
1259                 snprintf(errbuf, sizeof errbuf, noload ?
1260                         "Library %s is not already loaded" :
1261                         "Error loading shared library %s: %m",
1262                         file);
1263                 errflag = 1;
1264                 goto end;
1265         }
1266
1267         /* First load handling */
1268         if (!p->deps) {
1269                 load_deps(p);
1270                 if (p->deps) for (i=0; p->deps[i]; i++)
1271                         if (!p->deps[i]->global)
1272                                 p->deps[i]->global = -1;
1273                 if (!p->global) p->global = -1;
1274                 reloc_all(p);
1275                 if (p->deps) for (i=0; p->deps[i]; i++)
1276                         if (p->deps[i]->global < 0)
1277                                 p->deps[i]->global = 0;
1278                 if (p->global < 0) p->global = 0;
1279         }
1280
1281         if (mode & RTLD_GLOBAL) {
1282                 if (p->deps) for (i=0; p->deps[i]; i++)
1283                         p->deps[i]->global = 1;
1284                 p->global = 1;
1285         }
1286
1287         update_tls_size();
1288
1289         if (ssp_used) __init_ssp(libc.auxv);
1290
1291         _dl_debug_state();
1292         orig_tail = tail;
1293 end:
1294         __release_ptc();
1295         if (p) gencnt++;
1296         pthread_rwlock_unlock(&lock);
1297         if (p) do_init_fini(orig_tail);
1298         pthread_setcancelstate(cs, 0);
1299         return p;
1300 }
1301
1302 static int invalid_dso_handle(void *h)
1303 {
1304         struct dso *p;
1305         for (p=head; p; p=p->next) if (h==p) return 0;
1306         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1307         errflag = 1;
1308         return 1;
1309 }
1310
1311 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1312 {
1313         size_t i;
1314         uint32_t h = 0, gh = 0;
1315         Sym *sym;
1316         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1317                 if (p == RTLD_DEFAULT) {
1318                         p = head;
1319                 } else if (p == RTLD_NEXT) {
1320                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1321                         if (!p) p=head;
1322                         p = p->next;
1323                 }
1324                 struct symdef def = find_sym(p, s, 0);
1325                 if (!def.sym) goto failed;
1326                 if ((def.sym->st_info&0xf) == STT_TLS)
1327                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1328                 return def.dso->base + def.sym->st_value;
1329         }
1330         if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1331                 return 0;
1332         if (p->ghashtab) {
1333                 gh = gnu_hash(s);
1334                 sym = gnu_lookup(s, gh, p);
1335         } else {
1336                 h = sysv_hash(s);
1337                 sym = sysv_lookup(s, h, p);
1338         }
1339         if (sym && (sym->st_info&0xf) == STT_TLS)
1340                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1341         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1342                 return p->base + sym->st_value;
1343         if (p->deps) for (i=0; p->deps[i]; i++) {
1344                 if (p->deps[i]->ghashtab) {
1345                         if (!gh) gh = gnu_hash(s);
1346                         sym = gnu_lookup(s, gh, p->deps[i]);
1347                 } else {
1348                         if (!h) h = sysv_hash(s);
1349                         sym = sysv_lookup(s, h, p->deps[i]);
1350                 }
1351                 if (sym && (sym->st_info&0xf) == STT_TLS)
1352                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1353                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1354                         return p->deps[i]->base + sym->st_value;
1355         }
1356 failed:
1357         errflag = 1;
1358         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1359         return 0;
1360 }
1361
1362 int __dladdr(const void *addr, Dl_info *info)
1363 {
1364         struct dso *p;
1365         Sym *sym;
1366         uint32_t nsym;
1367         char *strings;
1368         size_t i;
1369         void *best = 0;
1370         char *bestname;
1371
1372         pthread_rwlock_rdlock(&lock);
1373         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1374         pthread_rwlock_unlock(&lock);
1375
1376         if (!p) return 0;
1377
1378         sym = p->syms;
1379         strings = p->strings;
1380         if (p->hashtab) {
1381                 nsym = p->hashtab[1];
1382         } else {
1383                 uint32_t *buckets;
1384                 uint32_t *hashval;
1385                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1386                 sym += p->ghashtab[1];
1387                 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1388                         if (buckets[i] > nsym)
1389                                 nsym = buckets[i];
1390                 }
1391                 if (nsym) {
1392                         nsym -= p->ghashtab[1];
1393                         hashval = buckets + p->ghashtab[0] + nsym;
1394                         do nsym++;
1395                         while (!(*hashval++ & 1));
1396                 }
1397         }
1398
1399         for (; nsym; nsym--, sym++) {
1400                 if (sym->st_value
1401                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1402                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1403                         void *symaddr = p->base + sym->st_value;
1404                         if (symaddr > addr || symaddr < best)
1405                                 continue;
1406                         best = symaddr;
1407                         bestname = strings + sym->st_name;
1408                         if (addr == symaddr)
1409                                 break;
1410                 }
1411         }
1412
1413         if (!best) return 0;
1414
1415         info->dli_fname = p->name;
1416         info->dli_fbase = p->base;
1417         info->dli_sname = bestname;
1418         info->dli_saddr = best;
1419
1420         return 1;
1421 }
1422
1423 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1424 {
1425         void *res;
1426         pthread_rwlock_rdlock(&lock);
1427         res = do_dlsym(p, s, ra);
1428         pthread_rwlock_unlock(&lock);
1429         return res;
1430 }
1431
1432 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1433 {
1434         struct dso *current;
1435         struct dl_phdr_info info;
1436         int ret = 0;
1437         for(current = head; current;) {
1438                 info.dlpi_addr      = (uintptr_t)current->base;
1439                 info.dlpi_name      = current->name;
1440                 info.dlpi_phdr      = current->phdr;
1441                 info.dlpi_phnum     = current->phnum;
1442                 info.dlpi_adds      = gencnt;
1443                 info.dlpi_subs      = 0;
1444                 info.dlpi_tls_modid = current->tls_id;
1445                 info.dlpi_tls_data  = current->tls_image;
1446
1447                 ret = (callback)(&info, sizeof (info), data);
1448
1449                 if (ret != 0) break;
1450
1451                 pthread_rwlock_rdlock(&lock);
1452                 current = current->next;
1453                 pthread_rwlock_unlock(&lock);
1454         }
1455         return ret;
1456 }
1457 #else
1458 static int invalid_dso_handle(void *h)
1459 {
1460         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1461         errflag = 1;
1462         return 1;
1463 }
1464 void *dlopen(const char *file, int mode)
1465 {
1466         return 0;
1467 }
1468 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1469 {
1470         return 0;
1471 }
1472 int __dladdr (const void *addr, Dl_info *info)
1473 {
1474         return 0;
1475 }
1476 #endif
1477
1478 int __dlinfo(void *dso, int req, void *res)
1479 {
1480         if (invalid_dso_handle(dso)) return -1;
1481         if (req != RTLD_DI_LINKMAP) {
1482                 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1483                 errflag = 1;
1484                 return -1;
1485         }
1486         *(struct link_map **)res = dso;
1487         return 0;
1488 }
1489
1490 char *dlerror()
1491 {
1492         if (!errflag) return 0;
1493         errflag = 0;
1494         return errbuf;
1495 }
1496
1497 int dlclose(void *p)
1498 {
1499         return invalid_dso_handle(p);
1500 }