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         int refcnt;
  60         Sym *syms;
  61         uint32_t *hashtab;
  62         uint32_t *ghashtab;
  63         int16_t *versym;
  64         char *strings;
  65         unsigned char *map;
  66         size_t map_len;
  67         dev_t dev;
  68         ino_t ino;
  69         signed char global;
  70         char relocated;
  71         char constructed;
  72         char kernel_mapped;
  73         struct dso **deps, *needed_by;
  74         char *rpath_orig, *rpath;
  75         void *tls_image;
  76         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  77         size_t relro_start, relro_end;
  78         void **new_dtv;
  79         unsigned char *new_tls;
  80         int new_dtv_idx, new_tls_idx;
  81         struct dso *fini_next;
  82         char *shortname;
  83         char buf[];
  84 };
  85
  86 struct symdef {
  87         Sym *sym;
  88         struct dso *dso;
  89 };
  90
  91 #include "reloc.h"
  92
  93 void __init_ssp(size_t *);
  94 int __init_tp(void *);
  95 void __init_libc(char **, char *);
  96
  97 const char *__libc_get_version(void);
  98
  99 static struct dso *head, *tail, *ldso, *fini_head;
 100 static char *env_path, *sys_path;
 101 static unsigned long long gencnt;
 102 static int ssp_used;
 103 static int runtime;
 104 static int ldd_mode;
 105 static int ldso_fail;
 106 static int noload;
 107 static jmp_buf *rtld_fail;
 108 static pthread_rwlock_t lock;
 109 static struct debug debug;
 110 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
 111 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 112 static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
 113
 114 struct debug *_dl_debug_addr = &debug;
 115
 116 #define AUX_CNT 38
 117 #define DYN_CNT 34
 118
 119 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 120 {
 121         memset(a, 0, cnt*sizeof(size_t));
 122         for (; v[0]; v+=2) if (v[0]<cnt) {
 123                 a[0] |= 1ULL<<v[0];
 124                 a[v[0]] = v[1];
 125         }
 126 }
 127
 128 static int search_vec(size_t *v, size_t *r, size_t key)
 129 {
 130         for (; v[0]!=key; v+=2)
 131                 if (!v[0]) return 0;
 132         *r = v[1];
 133         return 1;
 134 }
 135
 136 static uint32_t sysv_hash(const char *s0)
 137 {
 138         const unsigned char *s = (void *)s0;
 139         uint_fast32_t h = 0;
 140         while (*s) {
 141                 h = 16*h + *s++;
 142                 h ^= h>>24 & 0xf0;
 143         }
 144         return h & 0xfffffff;
 145 }
 146
 147 static uint32_t gnu_hash(const char *s0)
 148 {
 149         const unsigned char *s = (void *)s0;
 150         uint_fast32_t h = 5381;
 151         for (; *s; s++)
 152                 h = h*33 + *s;
 153         return h;
 154 }
 155
 156 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 157 {
 158         size_t i;
 159         Sym *syms = dso->syms;
 160         uint32_t *hashtab = dso->hashtab;
 161         char *strings = dso->strings;
 162         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 163                 if ((!dso->versym || dso->versym[i] >= 0)
 164                     && (!strcmp(s, strings+syms[i].st_name)))
 165                         return syms+i;
 166         }
 167         return 0;
 168 }
 169
 170 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 171 {
 172         Sym *syms = dso->syms;
 173         char *strings = dso->strings;
 174         uint32_t *hashtab = dso->ghashtab;
 175         uint32_t nbuckets = hashtab[0];
 176         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 177         uint32_t h2;
 178         uint32_t *hashval;
 179         uint32_t i = buckets[h1 % nbuckets];
 180
 181         if (!i) return 0;
 182
 183         hashval = buckets + nbuckets + (i - hashtab[1]);
 184
 185         for (h1 |= 1; ; i++) {
 186                 h2 = *hashval++;
 187                 if ((!dso->versym || dso->versym[i] >= 0)
 188                     && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
 189                         return syms+i;
 190                 if (h2 & 1) break;
 191         }
 192
 193         return 0;
 194 }
 195
 196 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 197 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 198
 199 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 200 {
 201         uint32_t h = 0, gh = 0;
 202         struct symdef def = {0};
 203         if (dso->ghashtab) {
 204                 gh = gnu_hash(s);
 205                 if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 206         } else {
 207                 h = sysv_hash(s);
 208                 if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 209         }
 210         for (; dso; dso=dso->next) {
 211                 Sym *sym;
 212                 if (!dso->global) continue;
 213                 if (dso->ghashtab) {
 214                         if (!gh) gh = gnu_hash(s);
 215                         sym = gnu_lookup(s, gh, dso);
 216                 } else {
 217                         if (!h) h = sysv_hash(s);
 218                         sym = sysv_lookup(s, h, dso);
 219                 }
 220                 if (!sym) continue;
 221                 if (!sym->st_shndx)
 222                         if (need_def || (sym->st_info&0xf) == STT_TLS)
 223                                 continue;
 224                 if (!sym->st_value)
 225                         if ((sym->st_info&0xf) != STT_TLS)
 226                                 continue;
 227                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 228                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 229
 230                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 231                 def.sym = sym;
 232                 def.dso = dso;
 233                 if (sym->st_info>>4 == STB_GLOBAL) break;
 234         }
 235         return def;
 236 }
 237
 238 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 239 {
 240         unsigned char *base = dso->base;
 241         Sym *syms = dso->syms;
 242         char *strings = dso->strings;
 243         Sym *sym;
 244         const char *name;
 245         void *ctx;
 246         int type;
 247         int sym_index;
 248         struct symdef def;
 249
 250         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 251                 type = R_TYPE(rel[1]);
 252                 sym_index = R_SYM(rel[1]);
 253                 if (sym_index) {
 254                         sym = syms + sym_index;
 255                         name = strings + sym->st_name;
 256                         ctx = IS_COPY(type) ? head->next : head;
 257                         def = find_sym(ctx, name, IS_PLT(type));
 258                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 259                             || sym->st_info>>4 != STB_WEAK)) {
 260                                 snprintf(errbuf, sizeof errbuf,
 261                                         "Error relocating %s: %s: symbol not found",
 262                                         dso->name, name);
 263                                 if (runtime) longjmp(*rtld_fail, 1);
 264                                 dprintf(2, "%s\n", errbuf);
 265                                 ldso_fail = 1;
 266                                 continue;
 267                         }
 268                 } else {
 269                         sym = 0;
 270                         def.sym = 0;
 271                         def.dso = 0;
 272                 }
 273                 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
 274                         stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
 275                         def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
 276         }
 277 }
 278
 279 /* A huge hack: to make up for the wastefulness of shared libraries
 280  * needing at least a page of dirty memory even if they have no global
 281  * data, we reclaim the gaps at the beginning and end of writable maps
 282  * and "donate" them to the heap by setting up minimal malloc
 283  * structures and then freeing them. */
 284
 285 static void reclaim(struct dso *dso, size_t start, size_t end)
 286 {
 287         size_t *a, *z;
 288         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 289         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 290         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 291         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 292         if (start>end || end-start < 4*sizeof(size_t)) return;
 293         a = (size_t *)(dso->base + start);
 294         z = (size_t *)(dso->base + end);
 295         a[-2] = 1;
 296         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 297         z[1] = 1;
 298         free(a);
 299 }
 300
 301 static void reclaim_gaps(struct dso *dso, Phdr *ph, size_t phent, size_t phcnt)
 302 {
 303         for (; phcnt--; ph=(void *)((char *)ph+phent)) {
 304                 if (ph->p_type!=PT_LOAD) continue;
 305                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 306                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 307                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 308                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 309         }
 310 }
 311
 312 static void *map_library(int fd, struct dso *dso)
 313 {
 314         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 315         void *allocated_buf=0;
 316         size_t phsize;
 317         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 318         size_t this_min, this_max;
 319         off_t off_start;
 320         Ehdr *eh;
 321         Phdr *ph, *ph0;
 322         unsigned prot;
 323         unsigned char *map=MAP_FAILED, *base;
 324         size_t dyn=0;
 325         size_t tls_image=0;
 326         size_t i;
 327
 328         ssize_t l = read(fd, buf, sizeof buf);
 329         eh = buf;
 330         if (l<0) return 0;
 331         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 332                 goto noexec;
 333         phsize = eh->e_phentsize * eh->e_phnum;
 334         if (phsize > sizeof buf - sizeof *eh) {
 335                 allocated_buf = malloc(phsize);
 336                 if (!allocated_buf) return 0;
 337                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 338                 if (l < 0) goto error;
 339                 if (l != phsize) goto noexec;
 340                 ph = ph0 = allocated_buf;
 341         } else if (eh->e_phoff + phsize > l) {
 342                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 343                 if (l < 0) goto error;
 344                 if (l != phsize) goto noexec;
 345                 ph = ph0 = (void *)(buf + 1);
 346         } else {
 347                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 348         }
 349         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 350                 if (ph->p_type == PT_DYNAMIC)
 351                         dyn = ph->p_vaddr;
 352                 else if (ph->p_type == PT_TLS) {
 353                         tls_image = ph->p_vaddr;
 354                         dso->tls_align = ph->p_align;
 355                         dso->tls_len = ph->p_filesz;
 356                         dso->tls_size = ph->p_memsz;
 357                 } else if (ph->p_type == PT_GNU_RELRO) {
 358                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 359                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 360                 }
 361                 if (ph->p_type != PT_LOAD) continue;
 362                 if (ph->p_vaddr < addr_min) {
 363                         addr_min = ph->p_vaddr;
 364                         off_start = ph->p_offset;
 365                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 366                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 367                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 368                 }
 369                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 370                         addr_max = ph->p_vaddr+ph->p_memsz;
 371                 }
 372         }
 373         if (!dyn) goto noexec;
 374         addr_max += PAGE_SIZE-1;
 375         addr_max &= -PAGE_SIZE;
 376         addr_min &= -PAGE_SIZE;
 377         off_start &= -PAGE_SIZE;
 378         map_len = addr_max - addr_min + off_start;
 379         /* The first time, we map too much, possibly even more than
 380          * the length of the file. This is okay because we will not
 381          * use the invalid part; we just need to reserve the right
 382          * amount of virtual address space to map over later. */
 383         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 384         if (map==MAP_FAILED) goto error;
 385         /* If the loaded file is not relocatable and the requested address is
 386          * not available, then the load operation must fail. */
 387         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 388                 errno = EBUSY;
 389                 goto error;
 390         }
 391         base = map - addr_min;
 392         dso->phdr = 0;
 393         dso->phnum = 0;
 394         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 395                 if (ph->p_type != PT_LOAD) continue;
 396                 /* Check if the programs headers are in this load segment, and
 397                  * if so, record the address for use by dl_iterate_phdr. */
 398                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 399                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 400                         dso->phdr = (void *)(base + ph->p_vaddr
 401                                 + (eh->e_phoff-ph->p_offset));
 402                         dso->phnum = eh->e_phnum;
 403                 }
 404                 /* Reuse the existing mapping for the lowest-address LOAD */
 405                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 406                 this_min = ph->p_vaddr & -PAGE_SIZE;
 407                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 408                 off_start = ph->p_offset & -PAGE_SIZE;
 409                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 410                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 411                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 412                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 413                         goto error;
 414                 if (ph->p_memsz > ph->p_filesz) {
 415                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 416                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 417                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 418                         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)
 419                                 goto error;
 420                 }
 421         }
 422         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 423                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 424                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 425                                 goto error;
 426                         break;
 427                 }
 428         dso->map = map;
 429         dso->map_len = map_len;
 430         dso->base = base;
 431         dso->dynv = (void *)(base+dyn);
 432         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 433         if (!runtime) reclaim_gaps(dso, ph0, eh->e_phentsize, eh->e_phnum);
 434         free(allocated_buf);
 435         return map;
 436 noexec:
 437         errno = ENOEXEC;
 438 error:
 439         if (map!=MAP_FAILED) munmap(map, map_len);
 440         free(allocated_buf);
 441         return 0;
 442 }
 443
 444 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 445 {
 446         size_t l;
 447         int fd;
 448         for (;;) {
 449                 s += strspn(s, ":\n");
 450                 l = strcspn(s, ":\n");
 451                 if (l-1 >= INT_MAX) return -1;
 452                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
 453                         continue;
 454                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 455                 s += l;
 456         }
 457 }
 458
 459 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 460 {
 461         size_t n, l;
 462         const char *s, *t, *origin;
 463         char *d;
 464         if (p->rpath) return 0;
 465         if (!p->rpath_orig) return -1;
 466         if (!strchr(p->rpath_orig, '$')) {
 467                 p->rpath = p->rpath_orig;
 468                 return 0;
 469         }
 470         n = 0;
 471         s = p->rpath_orig;
 472         while ((t=strchr(s, '$'))) {
 473                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 474                         return -1;
 475                 s = t+1;
 476                 n++;
 477         }
 478         if (n > SSIZE_MAX/PATH_MAX) return -1;
 479
 480         if (p->kernel_mapped) {
 481                 /* $ORIGIN searches cannot be performed for the main program
 482                  * when it is suid/sgid/AT_SECURE. This is because the
 483                  * pathname is under the control of the caller of execve.
 484                  * For libraries, however, $ORIGIN can be processed safely
 485                  * since the library's pathname came from a trusted source
 486                  * (either system paths or a call to dlopen). */
 487                 if (libc.secure)
 488                         return -1;
 489                 l = readlink("/proc/self/exe", buf, buf_size);
 490                 if (l >= buf_size)
 491                         return -1;
 492                 buf[l] = 0;
 493                 origin = buf;
 494         } else {
 495                 origin = p->name;
 496         }
 497         t = strrchr(origin, '/');
 498         l = t ? t-origin : 0;
 499         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 500         if (!p->rpath) return -1;
 501
 502         d = p->rpath;
 503         s = p->rpath_orig;
 504         while ((t=strchr(s, '$'))) {
 505                 memcpy(d, s, t-s);
 506                 d += t-s;
 507                 memcpy(d, origin, l);
 508                 d += l;
 509                 /* It was determined previously that the '$' is followed
 510                  * either by "ORIGIN" or "{ORIGIN}". */
 511                 s = t + 7 + 2*(t[1]=='{');
 512         }
 513         strcpy(d, s);
 514         return 0;
 515 }
 516
 517 static void decode_dyn(struct dso *p)
 518 {
 519         size_t dyn[DYN_CNT] = {0};
 520         decode_vec(p->dynv, dyn, DYN_CNT);
 521         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 522         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 523         if (dyn[0]&(1<<DT_HASH))
 524                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 525         if (dyn[0]&(1<<DT_RPATH))
 526                 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
 527         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 528                 p->ghashtab = (void *)(p->base + *dyn);
 529         if (search_vec(p->dynv, dyn, DT_VERSYM))
 530                 p->versym = (void *)(p->base + *dyn);
 531 }
 532
 533 static struct dso *load_library(const char *name, struct dso *needed_by)
 534 {
 535         char buf[2*NAME_MAX+2];
 536         const char *pathname;
 537         unsigned char *map;
 538         struct dso *p, temp_dso = {0};
 539         int fd;
 540         struct stat st;
 541         size_t alloc_size;
 542         int n_th = 0;
 543         int is_self = 0;
 544
 545         /* Catch and block attempts to reload the implementation itself */
 546         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 547                 static const char *rp, reserved[] =
 548                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 549                 char *z = strchr(name, '.');
 550                 if (z) {
 551                         size_t l = z-name;
 552                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 553                         if (*rp) {
 554                                 if (ldd_mode) {
 555                                         /* Track which names have been resolved
 556                                          * and only report each one once. */
 557                                         static unsigned reported;
 558                                         unsigned mask = 1U<<(rp-reserved);
 559                                         if (!(reported & mask)) {
 560                                                 reported |= mask;
 561                                                 dprintf(1, "\t%s => %s (%p)\n",
 562                                                         name, ldso->name,
 563                                                         ldso->base);
 564                                         }
 565                                 }
 566                                 is_self = 1;
 567                         }
 568                 }
 569         }
 570         if (!strcmp(name, ldso->name)) is_self = 1;
 571         if (is_self) {
 572                 if (!ldso->prev) {
 573                         tail->next = ldso;
 574                         ldso->prev = tail;
 575                         tail = ldso->next ? ldso->next : ldso;
 576                 }
 577                 return ldso;
 578         }
 579         if (strchr(name, '/')) {
 580                 pathname = name;
 581                 fd = open(name, O_RDONLY|O_CLOEXEC);
 582         } else {
 583                 /* Search for the name to see if it's already loaded */
 584                 for (p=head->next; p; p=p->next) {
 585                         if (p->shortname && !strcmp(p->shortname, name)) {
 586                                 p->refcnt++;
 587                                 return p;
 588                         }
 589                 }
 590                 if (strlen(name) > NAME_MAX) return 0;
 591                 fd = -1;
 592                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 593                 for (p=needed_by; fd < 0 && p; p=p->needed_by)
 594                         if (!fixup_rpath(p, buf, sizeof buf))
 595                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 596                 if (fd < 0) {
 597                         if (!sys_path) {
 598                                 char *prefix = 0;
 599                                 size_t prefix_len;
 600                                 if (ldso->name[0]=='/') {
 601                                         char *s, *t, *z;
 602                                         for (s=t=z=ldso->name; *s; s++)
 603                                                 if (*s=='/') z=t, t=s;
 604                                         prefix_len = z-ldso->name;
 605                                         if (prefix_len < PATH_MAX)
 606                                                 prefix = ldso->name;
 607                                 }
 608                                 if (!prefix) {
 609                                         prefix = "";
 610                                         prefix_len = 0;
 611                                 }
 612                                 char etc_ldso_path[prefix_len + 1
 613                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 614                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 615                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 616                                         (int)prefix_len, prefix);
 617                                 FILE *f = fopen(etc_ldso_path, "rbe");
 618                                 if (f) {
 619                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 620                                                 free(sys_path);
 621                                                 sys_path = "";
 622                                         }
 623                                         fclose(f);
 624                                 } else if (errno != ENOENT) {
 625                                         sys_path = "";
 626                                 }
 627                         }
 628                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 629                         fd = path_open(name, sys_path, buf, sizeof buf);
 630                 }
 631                 pathname = buf;
 632         }
 633         if (fd < 0) return 0;
 634         if (fstat(fd, &st) < 0) {
 635                 close(fd);
 636                 return 0;
 637         }
 638         for (p=head->next; p; p=p->next) {
 639                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 640                         /* If this library was previously loaded with a
 641                          * pathname but a search found the same inode,
 642                          * setup its shortname so it can be found by name. */
 643                         if (!p->shortname && pathname != name)
 644                                 p->shortname = strrchr(p->name, '/')+1;
 645                         close(fd);
 646                         p->refcnt++;
 647                         return p;
 648                 }
 649         }
 650         map = noload ? 0 : map_library(fd, &temp_dso);
 651         close(fd);
 652         if (!map) return 0;
 653
 654         /* Allocate storage for the new DSO. When there is TLS, this
 655          * storage must include a reservation for all pre-existing
 656          * threads to obtain copies of both the new TLS, and an
 657          * extended DTV capable of storing an additional slot for
 658          * the newly-loaded DSO. */
 659         alloc_size = sizeof *p + strlen(pathname) + 1;
 660         if (runtime && temp_dso.tls_image) {
 661                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 662                         + sizeof(void *) * (tls_cnt+3);
 663                 n_th = libc.threads_minus_1 + 1;
 664                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 665                 else alloc_size += n_th * per_th;
 666         }
 667         p = calloc(1, alloc_size);
 668         if (!p) {
 669                 munmap(map, temp_dso.map_len);
 670                 return 0;
 671         }
 672         memcpy(p, &temp_dso, sizeof temp_dso);
 673         decode_dyn(p);
 674         p->dev = st.st_dev;
 675         p->ino = st.st_ino;
 676         p->refcnt = 1;
 677         p->needed_by = needed_by;
 678         p->name = p->buf;
 679         strcpy(p->name, pathname);
 680         /* Add a shortname only if name arg was not an explicit pathname. */
 681         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 682         if (p->tls_image) {
 683                 if (runtime && !libc.has_thread_pointer) {
 684                         munmap(map, p->map_len);
 685                         free(p);
 686                         errno = ENOSYS;
 687                         return 0;
 688                 }
 689                 p->tls_id = ++tls_cnt;
 690                 tls_align = MAXP2(tls_align, p->tls_align);
 691 #ifdef TLS_ABOVE_TP
 692                 p->tls_offset = tls_offset + ( (tls_align-1) &
 693                         -(tls_offset + (uintptr_t)p->tls_image) );
 694                 tls_offset += p->tls_size;
 695 #else
 696                 tls_offset += p->tls_size + p->tls_align - 1;
 697                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 698                         & (p->tls_align-1);
 699                 p->tls_offset = tls_offset;
 700 #endif
 701                 p->new_dtv = (void *)(-sizeof(size_t) &
 702                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 703                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 704         }
 705
 706         tail->next = p;
 707         p->prev = tail;
 708         tail = p;
 709
 710         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 711
 712         return p;
 713 }
 714
 715 static void load_deps(struct dso *p)
 716 {
 717         size_t i, ndeps=0;
 718         struct dso ***deps = &p->deps, **tmp, *dep;
 719         for (; p; p=p->next) {
 720                 for (i=0; p->dynv[i]; i+=2) {
 721                         if (p->dynv[i] != DT_NEEDED) continue;
 722                         dep = load_library(p->strings + p->dynv[i+1], p);
 723                         if (!dep) {
 724                                 snprintf(errbuf, sizeof errbuf,
 725                                         "Error loading shared library %s: %m (needed by %s)",
 726                                         p->strings + p->dynv[i+1], p->name);
 727                                 if (runtime) longjmp(*rtld_fail, 1);
 728                                 dprintf(2, "%s\n", errbuf);
 729                                 ldso_fail = 1;
 730                                 continue;
 731                         }
 732                         if (runtime) {
 733                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 734                                 if (!tmp) longjmp(*rtld_fail, 1);
 735                                 tmp[ndeps++] = dep;
 736                                 tmp[ndeps] = 0;
 737                                 *deps = tmp;
 738                         }
 739                 }
 740         }
 741 }
 742
 743 static void load_preload(char *s)
 744 {
 745         int tmp;
 746         char *z;
 747         for (z=s; *z; s=z) {
 748                 for (   ; *s && isspace(*s); s++);
 749                 for (z=s; *z && !isspace(*z); z++);
 750                 tmp = *z;
 751                 *z = 0;
 752                 load_library(s, 0);
 753                 *z = tmp;
 754         }
 755 }
 756
 757 static void make_global(struct dso *p)
 758 {
 759         for (; p; p=p->next) p->global = 1;
 760 }
 761
 762 static void reloc_all(struct dso *p)
 763 {
 764         size_t dyn[DYN_CNT] = {0};
 765         for (; p; p=p->next) {
 766                 if (p->relocated) continue;
 767                 decode_vec(p->dynv, dyn, DYN_CNT);
 768 #ifdef NEED_ARCH_RELOCS
 769                 do_arch_relocs(p, head);
 770 #endif
 771                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 772                         2+(dyn[DT_PLTREL]==DT_RELA));
 773                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 774                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 775
 776                 if (p->relro_start != p->relro_end &&
 777                     mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) {
 778                         snprintf(errbuf, sizeof errbuf,
 779                                 "Error relocating %s: RELRO protection failed",
 780                                 p->name);
 781                         if (runtime) longjmp(*rtld_fail, 1);
 782                         dprintf(2, "%s\n", errbuf);
 783                         ldso_fail = 1;
 784                 }
 785
 786                 p->relocated = 1;
 787         }
 788 }
 789
 790 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
 791 {
 792         for (; cnt--; ph = (void *)((char *)ph + stride))
 793                 if (ph->p_type == PT_DYNAMIC)
 794                         return ph->p_vaddr;
 795         return 0;
 796 }
 797
 798 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
 799 {
 800         size_t min_addr = -1, max_addr = 0;
 801         for (; cnt--; ph = (void *)((char *)ph + stride)) {
 802                 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 }
 817
 818 static void do_fini()
 819 {
 820         struct dso *p;
 821         size_t dyn[DYN_CNT] = {0};
 822         for (p=fini_head; p; p=p->fini_next) {
 823                 if (!p->constructed) continue;
 824                 decode_vec(p->dynv, dyn, DYN_CNT);
 825                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
 826                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
 827                         size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
 828                         while (n--) ((void (*)(void))*--fn)();
 829                 }
 830 #ifndef NO_LEGACY_INITFINI
 831                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
 832                         ((void (*)(void))(p->base + dyn[DT_FINI]))();
 833 #endif
 834         }
 835 }
 836
 837 static void do_init_fini(struct dso *p)
 838 {
 839         size_t dyn[DYN_CNT] = {0};
 840         int need_locking = libc.threads_minus_1;
 841         /* Allow recursive calls that arise when a library calls
 842          * dlopen from one of its constructors, but block any
 843          * other threads until all ctors have finished. */
 844         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 845         for (; p; p=p->prev) {
 846                 if (p->constructed) continue;
 847                 p->constructed = 1;
 848                 decode_vec(p->dynv, dyn, DYN_CNT);
 849                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
 850                         p->fini_next = fini_head;
 851                         fini_head = p;
 852                 }
 853 #ifndef NO_LEGACY_INITFINI
 854                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
 855                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 856 #endif
 857                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
 858                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
 859                         size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
 860                         while (n--) ((void (*)(void))*fn++)();
 861                 }
 862                 if (!need_locking && libc.threads_minus_1) {
 863                         need_locking = 1;
 864                         pthread_mutex_lock(&init_fini_lock);
 865                 }
 866         }
 867         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 868 }
 869
 870 void _dl_debug_state(void)
 871 {
 872 }
 873
 874 void __reset_tls()
 875 {
 876         pthread_t self = __pthread_self();
 877         struct dso *p;
 878         for (p=head; p; p=p->next) {
 879                 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
 880                 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
 881                 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
 882                         p->tls_size - p->tls_len);
 883                 if (p->tls_id == (size_t)self->dtv[0]) break;
 884         }
 885 }
 886
 887 void *__copy_tls(unsigned char *mem)
 888 {
 889         pthread_t td;
 890         struct dso *p;
 891
 892         void **dtv = (void *)mem;
 893         dtv[0] = (void *)tls_cnt;
 894         if (!tls_cnt) {
 895                 td = (void *)(dtv+1);
 896                 td->dtv = dtv;
 897                 return td;
 898         }
 899
 900 #ifdef TLS_ABOVE_TP
 901         mem += sizeof(void *) * (tls_cnt+1);
 902         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
 903         td = (pthread_t)mem;
 904         mem += sizeof(struct pthread);
 905
 906         for (p=head; p; p=p->next) {
 907                 if (!p->tls_id) continue;
 908                 dtv[p->tls_id] = mem + p->tls_offset;
 909                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 910         }
 911 #else
 912         mem += libc.tls_size - sizeof(struct pthread);
 913         mem -= (uintptr_t)mem & (tls_align-1);
 914         td = (pthread_t)mem;
 915
 916         for (p=head; p; p=p->next) {
 917                 if (!p->tls_id) continue;
 918                 dtv[p->tls_id] = mem - p->tls_offset;
 919                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 920         }
 921 #endif
 922         td->dtv = dtv;
 923         return td;
 924 }
 925
 926 void *__tls_get_addr(size_t *v)
 927 {
 928         pthread_t self = __pthread_self();
 929         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
 930                 return (char *)self->dtv[v[0]]+v[1];
 931
 932         /* Block signals to make accessing new TLS async-signal-safe */
 933         sigset_t set;
 934         pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
 935         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
 936                 pthread_sigmask(SIG_SETMASK, &set, 0);
 937                 return (char *)self->dtv[v[0]]+v[1];
 938         }
 939
 940         /* This is safe without any locks held because, if the caller
 941          * is able to request the Nth entry of the DTV, the DSO list
 942          * must be valid at least that far out and it was synchronized
 943          * at program startup or by an already-completed call to dlopen. */
 944         struct dso *p;
 945         for (p=head; p->tls_id != v[0]; p=p->next);
 946
 947         /* Get new DTV space from new DSO if needed */
 948         if (v[0] > (size_t)self->dtv[0]) {
 949                 void **newdtv = p->new_dtv +
 950                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
 951                 memcpy(newdtv, self->dtv,
 952                         ((size_t)self->dtv[0]+1) * sizeof(void *));
 953                 newdtv[0] = (void *)v[0];
 954                 self->dtv = newdtv;
 955         }
 956
 957         /* Get new TLS memory from new DSO */
 958         unsigned char *mem = p->new_tls +
 959                 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
 960         mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
 961         self->dtv[v[0]] = mem;
 962         memcpy(mem, p->tls_image, p->tls_len);
 963         pthread_sigmask(SIG_SETMASK, &set, 0);
 964         return mem + v[1];
 965 }
 966
 967 static void update_tls_size()
 968 {
 969         libc.tls_size = ALIGN(
 970                 (1+tls_cnt) * sizeof(void *) +
 971                 tls_offset +
 972                 sizeof(struct pthread) +
 973                 tls_align * 2,
 974         tls_align);
 975 }
 976
 977 void *__dynlink(int argc, char **argv)
 978 {
 979         size_t aux[AUX_CNT] = {0};
 980         size_t i;
 981         Phdr *phdr;
 982         Ehdr *ehdr;
 983         static struct dso builtin_dsos[3];
 984         struct dso *const app = builtin_dsos+0;
 985         struct dso *const lib = builtin_dsos+1;
 986         struct dso *const vdso = builtin_dsos+2;
 987         char *env_preload=0;
 988         size_t vdso_base;
 989         size_t *auxv;
 990         char **envp = argv+argc+1;
 991         void *initial_tls;
 992
 993         /* Find aux vector just past environ[] */
 994         for (i=argc+1; argv[i]; i++)
 995                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
 996                         env_path = argv[i]+16;
 997                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
 998                         env_preload = argv[i]+11;
 999         auxv = (void *)(argv+i+1);
1000
1001         decode_vec(auxv, aux, AUX_CNT);
1002
1003         /* Only trust user/env if kernel says we're not suid/sgid */
1004         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1005           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
1006                 env_path = 0;
1007                 env_preload = 0;
1008                 libc.secure = 1;
1009         }
1010         libc.page_size = aux[AT_PAGESZ];
1011
1012         /* If the dynamic linker was invoked as a program itself, AT_BASE
1013          * will not be set. In that case, we assume the base address is
1014          * the start of the page containing the PHDRs; I don't know any
1015          * better approach... */
1016         if (!aux[AT_BASE]) {
1017                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
1018                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
1019         }
1020
1021         /* The dynamic linker load address is passed by the kernel
1022          * in the AUX vector, so this is easy. */
1023         lib->base = (void *)aux[AT_BASE];
1024         lib->name = lib->shortname = "libc.so";
1025         lib->global = 1;
1026         lib->kernel_mapped = 1;
1027         ehdr = (void *)lib->base;
1028         lib->phnum = ehdr->e_phnum;
1029         lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1030         find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
1031         lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
1032                 ehdr->e_phnum, ehdr->e_phentsize));
1033         decode_dyn(lib);
1034
1035         if (aux[AT_PHDR]) {
1036                 size_t interp_off = 0;
1037                 size_t tls_image = 0;
1038                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1039                 app->phdr = phdr = (void *)aux[AT_PHDR];
1040                 app->phnum = aux[AT_PHNUM];
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                 app->kernel_mapped = 1;
1061                 app->dynv = (void *)(app->base + find_dyn(
1062                         (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
1063                 find_map_range((void *)aux[AT_PHDR],
1064                         aux[AT_PHNUM], aux[AT_PHENT], app);
1065         } else {
1066                 int fd;
1067                 char *ldname = argv[0];
1068                 size_t l = strlen(ldname);
1069                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1070                 *argv++ = (void *)-1;
1071                 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
1072                 if (!argv[0]) {
1073                         dprintf(2, "musl libc\n"
1074                                 "Version %s\n"
1075                                 "Dynamic Program Loader\n"
1076                                 "Usage: %s [--] pathname%s\n",
1077                                 __libc_get_version(), ldname,
1078                                 ldd_mode ? "" : " [args]");
1079                         _exit(1);
1080                 }
1081                 fd = open(argv[0], O_RDONLY);
1082                 if (fd < 0) {
1083                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1084                         _exit(1);
1085                 }
1086                 runtime = 1;
1087                 ehdr = (void *)map_library(fd, app);
1088                 if (!ehdr) {
1089                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1090                         _exit(1);
1091                 }
1092                 runtime = 0;
1093                 close(fd);
1094                 lib->name = ldname;
1095                 app->name = argv[0];
1096                 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1097                 /* Find the name that would have been used for the dynamic
1098                  * linker had ldd not taken its place. */
1099                 if (ldd_mode) {
1100                         for (i=0; i<app->phnum; i++) {
1101                                 if (app->phdr[i].p_type == PT_INTERP)
1102                                         lib->name = (void *)(app->base
1103                                                 + app->phdr[i].p_vaddr);
1104                         }
1105                         dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1106                 }
1107         }
1108         if (app->tls_size) {
1109                 app->tls_id = tls_cnt = 1;
1110 #ifdef TLS_ABOVE_TP
1111                 app->tls_offset = 0;
1112                 tls_offset = app->tls_size
1113                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1114                         & (app->tls_align-1) );
1115 #else
1116                 tls_offset = app->tls_offset = app->tls_size
1117                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1118                         & (app->tls_align-1) );
1119 #endif
1120                 tls_align = MAXP2(tls_align, app->tls_align);
1121         }
1122         app->global = 1;
1123         decode_dyn(app);
1124
1125         /* Attach to vdso, if provided by the kernel */
1126         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1127                 ehdr = (void *)vdso_base;
1128                 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1129                 vdso->phnum = ehdr->e_phnum;
1130                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1131                         if (phdr->p_type == PT_DYNAMIC)
1132                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1133                         if (phdr->p_type == PT_LOAD)
1134                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1135                 }
1136                 vdso->name = "";
1137                 vdso->shortname = "linux-gate.so.1";
1138                 vdso->global = 1;
1139                 decode_dyn(vdso);
1140                 vdso->prev = lib;
1141                 lib->next = vdso;
1142         }
1143
1144         /* Initial dso chain consists only of the app. We temporarily
1145          * append the dynamic linker/libc so we can relocate it, then
1146          * restore the initial chain in preparation for loading third
1147          * party libraries (preload/needed). */
1148         head = tail = app;
1149         ldso = lib;
1150         app->next = lib;
1151         reloc_all(lib);
1152         app->next = 0;
1153
1154         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1155
1156         /* Donate unused parts of app and library mapping to malloc */
1157         reclaim_gaps(app, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
1158         ehdr = (void *)lib->base;
1159         reclaim_gaps(lib, (void *)(lib->base+ehdr->e_phoff),
1160                 ehdr->e_phentsize, ehdr->e_phnum);
1161
1162         /* Load preload/needed libraries, add their symbols to the global
1163          * namespace, and perform all remaining relocations. The main
1164          * program must be relocated LAST since it may contain copy
1165          * relocations which depend on libraries' relocations. */
1166         if (env_preload) load_preload(env_preload);
1167         load_deps(app);
1168         make_global(app);
1169
1170 #ifndef DYNAMIC_IS_RO
1171         for (i=0; app->dynv[i]; i+=2)
1172                 if (app->dynv[i]==DT_DEBUG)
1173                         app->dynv[i+1] = (size_t)&debug;
1174 #endif
1175
1176         reloc_all(app->next);
1177         reloc_all(app);
1178
1179         update_tls_size();
1180         if (libc.tls_size > sizeof builtin_tls) {
1181                 initial_tls = calloc(libc.tls_size, 1);
1182                 if (!initial_tls) {
1183                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1184                                 argv[0], libc.tls_size);
1185                         _exit(127);
1186                 }
1187         } else {
1188                 initial_tls = builtin_tls;
1189         }
1190         if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
1191                 dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
1192                 _exit(127);
1193         }
1194
1195         if (ldso_fail) _exit(127);
1196         if (ldd_mode) _exit(0);
1197
1198         /* Switch to runtime mode: any further failures in the dynamic
1199          * linker are a reportable failure rather than a fatal startup
1200          * error. If the dynamic loader (dlopen) will not be used, free
1201          * all memory used by the dynamic linker. */
1202         runtime = 1;
1203
1204         debug.ver = 1;
1205         debug.bp = _dl_debug_state;
1206         debug.head = head;
1207         debug.base = lib->base;
1208         debug.state = 0;
1209         _dl_debug_state();
1210
1211         if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1212         __init_libc(envp, argv[0]);
1213         atexit(do_fini);
1214         errno = 0;
1215         do_init_fini(tail);
1216
1217         return (void *)aux[AT_ENTRY];
1218 }
1219
1220 void *dlopen(const char *file, int mode)
1221 {
1222         struct dso *volatile p, *orig_tail, *next;
1223         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1224         size_t i;
1225         int cs;
1226         jmp_buf jb;
1227
1228         if (!file) return head;
1229
1230         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1231         pthread_rwlock_wrlock(&lock);
1232         __inhibit_ptc();
1233
1234         p = 0;
1235         orig_tls_cnt = tls_cnt;
1236         orig_tls_offset = tls_offset;
1237         orig_tls_align = tls_align;
1238         orig_tail = tail;
1239         noload = mode & RTLD_NOLOAD;
1240
1241         rtld_fail = &jb;
1242         if (setjmp(*rtld_fail)) {
1243                 /* Clean up anything new that was (partially) loaded */
1244                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1245                         if (p->deps[i]->global < 0)
1246                                 p->deps[i]->global = 0;
1247                 for (p=orig_tail->next; p; p=next) {
1248                         next = p->next;
1249                         munmap(p->map, p->map_len);
1250                         free(p->deps);
1251                         free(p);
1252                 }
1253                 tls_cnt = orig_tls_cnt;
1254                 tls_offset = orig_tls_offset;
1255                 tls_align = orig_tls_align;
1256                 tail = orig_tail;
1257                 tail->next = 0;
1258                 p = 0;
1259                 errflag = 1;
1260                 goto end;
1261         } else p = load_library(file, head);
1262
1263         if (!p) {
1264                 snprintf(errbuf, sizeof errbuf, noload ?
1265                         "Library %s is not already loaded" :
1266                         "Error loading shared library %s: %m",
1267                         file);
1268                 errflag = 1;
1269                 goto end;
1270         }
1271
1272         /* First load handling */
1273         if (!p->deps) {
1274                 load_deps(p);
1275                 if (p->deps) for (i=0; p->deps[i]; i++)
1276                         if (!p->deps[i]->global)
1277                                 p->deps[i]->global = -1;
1278                 if (!p->global) p->global = -1;
1279                 reloc_all(p);
1280                 if (p->deps) for (i=0; p->deps[i]; i++)
1281                         if (p->deps[i]->global < 0)
1282                                 p->deps[i]->global = 0;
1283                 if (p->global < 0) p->global = 0;
1284         }
1285
1286         if (mode & RTLD_GLOBAL) {
1287                 if (p->deps) for (i=0; p->deps[i]; i++)
1288                         p->deps[i]->global = 1;
1289                 p->global = 1;
1290         }
1291
1292         update_tls_size();
1293
1294         if (ssp_used) __init_ssp(libc.auxv);
1295
1296         _dl_debug_state();
1297         orig_tail = tail;
1298 end:
1299         __release_ptc();
1300         if (p) gencnt++;
1301         pthread_rwlock_unlock(&lock);
1302         if (p) do_init_fini(orig_tail);
1303         pthread_setcancelstate(cs, 0);
1304         return p;
1305 }
1306
1307 static int invalid_dso_handle(void *h)
1308 {
1309         struct dso *p;
1310         for (p=head; p; p=p->next) if (h==p) return 0;
1311         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1312         errflag = 1;
1313         return 1;
1314 }
1315
1316 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1317 {
1318         size_t i;
1319         uint32_t h = 0, gh = 0;
1320         Sym *sym;
1321         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1322                 if (p == RTLD_DEFAULT) {
1323                         p = head;
1324                 } else if (p == RTLD_NEXT) {
1325                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1326                         if (!p) p=head;
1327                         p = p->next;
1328                 }
1329                 struct symdef def = find_sym(p, s, 0);
1330                 if (!def.sym) goto failed;
1331                 if ((def.sym->st_info&0xf) == STT_TLS)
1332                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1333                 return def.dso->base + def.sym->st_value;
1334         }
1335         if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1336                 return 0;
1337         if (p->ghashtab) {
1338                 gh = gnu_hash(s);
1339                 sym = gnu_lookup(s, gh, p);
1340         } else {
1341                 h = sysv_hash(s);
1342                 sym = sysv_lookup(s, h, p);
1343         }
1344         if (sym && (sym->st_info&0xf) == STT_TLS)
1345                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1346         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1347                 return p->base + sym->st_value;
1348         if (p->deps) for (i=0; p->deps[i]; i++) {
1349                 if (p->deps[i]->ghashtab) {
1350                         if (!gh) gh = gnu_hash(s);
1351                         sym = gnu_lookup(s, gh, p->deps[i]);
1352                 } else {
1353                         if (!h) h = sysv_hash(s);
1354                         sym = sysv_lookup(s, h, p->deps[i]);
1355                 }
1356                 if (sym && (sym->st_info&0xf) == STT_TLS)
1357                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1358                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1359                         return p->deps[i]->base + sym->st_value;
1360         }
1361 failed:
1362         errflag = 1;
1363         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1364         return 0;
1365 }
1366
1367 int __dladdr(const void *addr, Dl_info *info)
1368 {
1369         struct dso *p;
1370         Sym *sym;
1371         uint32_t nsym;
1372         char *strings;
1373         size_t i;
1374         void *best = 0;
1375         char *bestname;
1376
1377         pthread_rwlock_rdlock(&lock);
1378         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1379         pthread_rwlock_unlock(&lock);
1380
1381         if (!p) return 0;
1382
1383         sym = p->syms;
1384         strings = p->strings;
1385         if (p->hashtab) {
1386                 nsym = p->hashtab[1];
1387         } else {
1388                 uint32_t *buckets;
1389                 uint32_t *hashval;
1390                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1391                 sym += p->ghashtab[1];
1392                 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1393                         if (buckets[i] > nsym)
1394                                 nsym = buckets[i];
1395                 }
1396                 if (nsym) {
1397                         nsym -= p->ghashtab[1];
1398                         hashval = buckets + p->ghashtab[0] + nsym;
1399                         do nsym++;
1400                         while (!(*hashval++ & 1));
1401                 }
1402         }
1403
1404         for (; nsym; nsym--, sym++) {
1405                 if (sym->st_value
1406                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1407                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1408                         void *symaddr = p->base + sym->st_value;
1409                         if (symaddr > addr || symaddr < best)
1410                                 continue;
1411                         best = symaddr;
1412                         bestname = strings + sym->st_name;
1413                         if (addr == symaddr)
1414                                 break;
1415                 }
1416         }
1417
1418         if (!best) return 0;
1419
1420         info->dli_fname = p->name;
1421         info->dli_fbase = p->base;
1422         info->dli_sname = bestname;
1423         info->dli_saddr = best;
1424
1425         return 1;
1426 }
1427
1428 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1429 {
1430         void *res;
1431         pthread_rwlock_rdlock(&lock);
1432         res = do_dlsym(p, s, ra);
1433         pthread_rwlock_unlock(&lock);
1434         return res;
1435 }
1436
1437 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1438 {
1439         struct dso *current;
1440         struct dl_phdr_info info;
1441         int ret = 0;
1442         for(current = head; current;) {
1443                 info.dlpi_addr      = (uintptr_t)current->base;
1444                 info.dlpi_name      = current->name;
1445                 info.dlpi_phdr      = current->phdr;
1446                 info.dlpi_phnum     = current->phnum;
1447                 info.dlpi_adds      = gencnt;
1448                 info.dlpi_subs      = 0;
1449                 info.dlpi_tls_modid = current->tls_id;
1450                 info.dlpi_tls_data  = current->tls_image;
1451
1452                 ret = (callback)(&info, sizeof (info), data);
1453
1454                 if (ret != 0) break;
1455
1456                 pthread_rwlock_rdlock(&lock);
1457                 current = current->next;
1458                 pthread_rwlock_unlock(&lock);
1459         }
1460         return ret;
1461 }
1462 #else
1463 static int invalid_dso_handle(void *h)
1464 {
1465         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1466         errflag = 1;
1467         return 1;
1468 }
1469 void *dlopen(const char *file, int mode)
1470 {
1471         return 0;
1472 }
1473 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1474 {
1475         return 0;
1476 }
1477 int __dladdr (const void *addr, Dl_info *info)
1478 {
1479         return 0;
1480 }
1481 #endif
1482
1483 int __dlinfo(void *dso, int req, void *res)
1484 {
1485         if (invalid_dso_handle(dso)) return -1;
1486         if (req != RTLD_DI_LINKMAP) {
1487                 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1488                 errflag = 1;
1489                 return -1;
1490         }
1491         *(struct link_map **)res = dso;
1492         return 0;
1493 }
1494
1495 char *dlerror()
1496 {
1497         if (!errflag) return 0;
1498         errflag = 0;
1499         return errbuf;
1500 }
1501
1502 int dlclose(void *p)
1503 {
1504         return invalid_dso_handle(p);
1505 }