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 <stdint.h>
  11 #include <fcntl.h>
  12 #include <sys/stat.h>
  13 #include <errno.h>
  14 #include <limits.h>
  15 #include <elf.h>
  16 #include <setjmp.h>
  17 #include <pthread.h>
  18 #include <ctype.h>
  19 #include <dlfcn.h>
  20 #include "pthread_impl.h"
  21 #include "libc.h"
  22 #undef libc
  23
  24 static int errflag;
  25 static char errbuf[128];
  26
  27 #ifdef SHARED
  28
  29 #if ULONG_MAX == 0xffffffff
  30 typedef Elf32_Ehdr Ehdr;
  31 typedef Elf32_Phdr Phdr;
  32 typedef Elf32_Sym Sym;
  33 #define R_TYPE(x) ((x)&255)
  34 #define R_SYM(x) ((x)>>8)
  35 #else
  36 typedef Elf64_Ehdr Ehdr;
  37 typedef Elf64_Phdr Phdr;
  38 typedef Elf64_Sym Sym;
  39 #define R_TYPE(x) ((x)&0xffffffff)
  40 #define R_SYM(x) ((x)>>32)
  41 #endif
  42
  43 #define MAXP2(a,b) (-(-(a)&-(b)))
  44 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  45
  46 struct debug {
  47         int ver;
  48         void *head;
  49         void (*bp)(void);
  50         int state;
  51         void *base;
  52 };
  53
  54 struct dso {
  55         unsigned char *base;
  56         char *name;
  57         size_t *dynv;
  58         struct dso *next, *prev;
  59
  60         int refcnt;
  61         Sym *syms;
  62         uint32_t *hashtab;
  63         uint32_t *ghashtab;
  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         struct dso **deps;
  73         void *tls_image;
  74         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  75         void **new_dtv;
  76         unsigned char *new_tls;
  77         int new_dtv_idx, new_tls_idx;
  78         struct dso *fini_next;
  79         char *shortname;
  80         char buf[];
  81 };
  82
  83 struct symdef {
  84         Sym *sym;
  85         struct dso *dso;
  86 };
  87
  88 #include "reloc.h"
  89
  90 void __init_ssp(size_t *);
  91 void *__install_initial_tls(void *);
  92
  93 static struct dso *head, *tail, *libc, *fini_head;
  94 static char *env_path, *sys_path, *r_path;
  95 static int ssp_used;
  96 static int runtime;
  97 static int ldd_mode;
  98 static int ldso_fail;
  99 static jmp_buf rtld_fail;
 100 static pthread_rwlock_t lock;
 101 static struct debug debug;
 102 static size_t *auxv;
 103 static size_t tls_cnt, tls_offset, tls_start, tls_align = 4*sizeof(size_t);
 104 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 105
 106 struct debug *_dl_debug_addr = &debug;
 107
 108 #define AUX_CNT 38
 109 #define DYN_CNT 34
 110
 111 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 112 {
 113         memset(a, 0, cnt*sizeof(size_t));
 114         for (; v[0]; v+=2) if (v[0]<cnt) {
 115                 a[0] |= 1ULL<<v[0];
 116                 a[v[0]] = v[1];
 117         }
 118 }
 119
 120 static int search_vec(size_t *v, size_t *r, size_t key)
 121 {
 122         for (; v[0]!=key; v+=2)
 123                 if (!v[0]) return 0;
 124         *r = v[1];
 125         return 1;
 126 }
 127
 128 static uint32_t sysv_hash(const char *s0)
 129 {
 130         const unsigned char *s = (void *)s0;
 131         uint_fast32_t h = 0;
 132         while (*s) {
 133                 h = 16*h + *s++;
 134                 h ^= h>>24 & 0xf0;
 135         }
 136         return h & 0xfffffff;
 137 }
 138
 139 static uint32_t gnu_hash(const char *s0)
 140 {
 141         const unsigned char *s = (void *)s0;
 142         uint_fast32_t h = 5381;
 143         for (; *s; s++)
 144                 h = h*33 + *s;
 145         return h;
 146 }
 147
 148 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 149 {
 150         size_t i;
 151         Sym *syms = dso->syms;
 152         uint32_t *hashtab = dso->hashtab;
 153         char *strings = dso->strings;
 154         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 155                 if (!strcmp(s, strings+syms[i].st_name))
 156                         return syms+i;
 157         }
 158         return 0;
 159 }
 160
 161 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 162 {
 163         Sym *sym;
 164         char *strings;
 165         uint32_t *hashtab = dso->ghashtab;
 166         uint32_t nbuckets = hashtab[0];
 167         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 168         uint32_t h2;
 169         uint32_t *hashval;
 170         uint32_t n = buckets[h1 % nbuckets];
 171
 172         if (!n) return 0;
 173
 174         strings = dso->strings;
 175         sym = dso->syms + n;
 176         hashval = buckets + nbuckets + (n - hashtab[1]);
 177
 178         for (h1 |= 1; ; sym++) {
 179                 h2 = *hashval++;
 180                 if ((h1 == (h2|1)) && !strcmp(s, strings + sym->st_name))
 181                         return sym;
 182                 if (h2 & 1) break;
 183         }
 184
 185         return 0;
 186 }
 187
 188 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 189 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK)
 190
 191 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 192 {
 193         uint32_t h = 0, gh = 0;
 194         struct symdef def = {0};
 195         if (dso->ghashtab) {
 196                 gh = gnu_hash(s);
 197                 if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 198         } else {
 199                 h = sysv_hash(s);
 200                 if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 201         }
 202         for (; dso; dso=dso->next) {
 203                 Sym *sym;
 204                 if (!dso->global) continue;
 205                 if (dso->ghashtab) {
 206                         if (!gh) gh = gnu_hash(s);
 207                         sym = gnu_lookup(s, gh, dso);
 208                 } else {
 209                         if (!h) h = sysv_hash(s);
 210                         sym = sysv_lookup(s, h, dso);
 211                 }
 212                 if (!sym) continue;
 213                 if (!sym->st_shndx)
 214                         if (need_def || (sym->st_info&0xf) == STT_TLS)
 215                                 continue;
 216                 if (!sym->st_value)
 217                         if ((sym->st_info&0xf) != STT_TLS)
 218                                 continue;
 219                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 220                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 221
 222                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 223                 def.sym = sym;
 224                 def.dso = dso;
 225                 if (sym->st_info>>4 == STB_GLOBAL) break;
 226         }
 227         return def;
 228 }
 229
 230 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 231 {
 232         unsigned char *base = dso->base;
 233         Sym *syms = dso->syms;
 234         char *strings = dso->strings;
 235         Sym *sym;
 236         const char *name;
 237         void *ctx;
 238         int type;
 239         int sym_index;
 240         struct symdef def;
 241
 242         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 243                 type = R_TYPE(rel[1]);
 244                 sym_index = R_SYM(rel[1]);
 245                 if (sym_index) {
 246                         sym = syms + sym_index;
 247                         name = strings + sym->st_name;
 248                         ctx = IS_COPY(type) ? head->next : head;
 249                         def = find_sym(ctx, name, IS_PLT(type));
 250                         if (!def.sym && sym->st_info>>4 != STB_WEAK) {
 251                                 snprintf(errbuf, sizeof errbuf,
 252                                         "Error relocating %s: %s: symbol not found",
 253                                         dso->name, name);
 254                                 if (runtime) longjmp(rtld_fail, 1);
 255                                 dprintf(2, "%s\n", errbuf);
 256                                 ldso_fail = 1;
 257                                 continue;
 258                         }
 259                 } else {
 260                         sym = 0;
 261                         def.sym = 0;
 262                         def.dso = 0;
 263                 }
 264                 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
 265                         stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
 266                         def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
 267         }
 268 }
 269
 270 /* A huge hack: to make up for the wastefulness of shared libraries
 271  * needing at least a page of dirty memory even if they have no global
 272  * data, we reclaim the gaps at the beginning and end of writable maps
 273  * and "donate" them to the heap by setting up minimal malloc
 274  * structures and then freeing them. */
 275
 276 static void reclaim(unsigned char *base, size_t start, size_t end)
 277 {
 278         size_t *a, *z;
 279         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 280         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 281         if (start>end || end-start < 4*sizeof(size_t)) return;
 282         a = (size_t *)(base + start);
 283         z = (size_t *)(base + end);
 284         a[-2] = 1;
 285         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 286         z[1] = 1;
 287         free(a);
 288 }
 289
 290 static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
 291 {
 292         for (; phcnt--; ph=(void *)((char *)ph+phent)) {
 293                 if (ph->p_type!=PT_LOAD) continue;
 294                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 295                 reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 296                 reclaim(base, ph->p_vaddr+ph->p_memsz,
 297                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 298         }
 299 }
 300
 301 static void *map_library(int fd, struct dso *dso)
 302 {
 303         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 304         size_t phsize;
 305         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 306         size_t this_min, this_max;
 307         off_t off_start;
 308         Ehdr *eh;
 309         Phdr *ph;
 310         unsigned prot;
 311         unsigned char *map, *base;
 312         size_t dyn;
 313         size_t tls_image=0;
 314         size_t i;
 315
 316         ssize_t l = read(fd, buf, sizeof buf);
 317         if (l<sizeof *eh) return 0;
 318         eh = buf;
 319         phsize = eh->e_phentsize * eh->e_phnum;
 320         if (phsize + sizeof *eh > l) return 0;
 321         if (eh->e_phoff + phsize > l) {
 322                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 323                 if (l != phsize) return 0;
 324                 eh->e_phoff = sizeof *eh;
 325         }
 326         ph = (void *)((char *)buf + eh->e_phoff);
 327         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 328                 if (ph->p_type == PT_DYNAMIC)
 329                         dyn = ph->p_vaddr;
 330                 if (ph->p_type == PT_TLS) {
 331                         tls_image = ph->p_vaddr;
 332                         dso->tls_align = ph->p_align;
 333                         dso->tls_len = ph->p_filesz;
 334                         dso->tls_size = ph->p_memsz;
 335                 }
 336                 if (ph->p_type != PT_LOAD) continue;
 337                 if (ph->p_vaddr < addr_min) {
 338                         addr_min = ph->p_vaddr;
 339                         off_start = ph->p_offset;
 340                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 341                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 342                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 343                 }
 344                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 345                         addr_max = ph->p_vaddr+ph->p_memsz;
 346                 }
 347         }
 348         if (!dyn) return 0;
 349         addr_max += PAGE_SIZE-1;
 350         addr_max &= -PAGE_SIZE;
 351         addr_min &= -PAGE_SIZE;
 352         off_start &= -PAGE_SIZE;
 353         map_len = addr_max - addr_min + off_start;
 354         /* The first time, we map too much, possibly even more than
 355          * the length of the file. This is okay because we will not
 356          * use the invalid part; we just need to reserve the right
 357          * amount of virtual address space to map over later. */
 358         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 359         if (map==MAP_FAILED) return 0;
 360         base = map - addr_min;
 361         ph = (void *)((char *)buf + eh->e_phoff);
 362         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 363                 if (ph->p_type != PT_LOAD) continue;
 364                 /* Reuse the existing mapping for the lowest-address LOAD */
 365                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 366                 this_min = ph->p_vaddr & -PAGE_SIZE;
 367                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 368                 off_start = ph->p_offset & -PAGE_SIZE;
 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                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 373                         goto error;
 374                 if (ph->p_memsz > ph->p_filesz) {
 375                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 376                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 377                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 378                         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)
 379                                 goto error;
 380                 }
 381         }
 382         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 383                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 384                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 385                                 goto error;
 386                         break;
 387                 }
 388         if (!runtime) reclaim_gaps(base, (void *)((char *)buf + eh->e_phoff),
 389                 eh->e_phentsize, eh->e_phnum);
 390         dso->map = map;
 391         dso->map_len = map_len;
 392         dso->base = base;
 393         dso->dynv = (void *)(base+dyn);
 394         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 395         return map;
 396 error:
 397         munmap(map, map_len);
 398         return 0;
 399 }
 400
 401 static int path_open(const char *name, const char *search, char *buf, size_t buf_size)
 402 {
 403         const char *s=search, *z;
 404         int l, fd;
 405         for (;;) {
 406                 while (*s==':') s++;
 407                 if (!*s) return -1;
 408                 z = strchr(s, ':');
 409                 l = z ? z-s : strlen(s);
 410                 snprintf(buf, buf_size, "%.*s/%s", l, s, name);
 411                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 412                 s += l;
 413         }
 414 }
 415
 416 static void decode_dyn(struct dso *p)
 417 {
 418         size_t dyn[DYN_CNT] = {0};
 419         decode_vec(p->dynv, dyn, DYN_CNT);
 420         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 421         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 422         if (dyn[0]&(1<<DT_HASH))
 423                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 424         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 425                 p->ghashtab = (void *)(p->base + *dyn);
 426 }
 427
 428 static struct dso *load_library(const char *name)
 429 {
 430         char buf[2*NAME_MAX+2];
 431         const char *pathname;
 432         unsigned char *base, *map;
 433         size_t dyno, map_len;
 434         struct dso *p, temp_dso = {0};
 435         int fd;
 436         struct stat st;
 437         size_t alloc_size;
 438         int n_th = 0;
 439
 440         /* Catch and block attempts to reload the implementation itself */
 441         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 442                 static const char *rp, reserved[] =
 443                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 444                 char *z = strchr(name, '.');
 445                 if (z) {
 446                         size_t l = z-name;
 447                         for (rp=reserved; *rp && memcmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 448                         if (*rp) {
 449                                 if (!libc->prev) {
 450                                         tail->next = libc;
 451                                         libc->prev = tail;
 452                                         tail = libc->next ? libc->next : libc;
 453                                 }
 454                                 return libc;
 455                         }
 456                 }
 457         }
 458         if (strchr(name, '/')) {
 459                 pathname = name;
 460                 fd = open(name, O_RDONLY|O_CLOEXEC);
 461         } else {
 462                 /* Search for the name to see if it's already loaded */
 463                 for (p=head->next; p; p=p->next) {
 464                         if (p->shortname && !strcmp(p->shortname, name)) {
 465                                 p->refcnt++;
 466                                 return p;
 467                         }
 468                 }
 469                 if (strlen(name) > NAME_MAX) return 0;
 470                 fd = -1;
 471                 if (r_path) fd = path_open(name, r_path, buf, sizeof buf);
 472                 if (fd < 0 && env_path) fd = path_open(name, env_path, buf, sizeof buf);
 473                 if (fd < 0) {
 474                         if (!sys_path) {
 475                                 FILE *f = fopen(ETC_LDSO_PATH, "rbe");
 476                                 if (f) {
 477                                         if (getline(&sys_path, (size_t[1]){0}, f) > 0)
 478                                                 sys_path[strlen(sys_path)-1]=0;
 479                                         fclose(f);
 480                                 }
 481                         }
 482                         if (sys_path) fd = path_open(name, sys_path, buf, sizeof buf);
 483                         else fd = path_open(name, "/lib:/usr/local/lib:/usr/lib", buf, sizeof buf);
 484                 }
 485                 pathname = buf;
 486         }
 487         if (fd < 0) return 0;
 488         if (fstat(fd, &st) < 0) {
 489                 close(fd);
 490                 return 0;
 491         }
 492         for (p=head->next; p; p=p->next) {
 493                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 494                         /* If this library was previously loaded with a
 495                          * pathname but a search found the same inode,
 496                          * setup its shortname so it can be found by name. */
 497                         if (!p->shortname && pathname != name)
 498                                 p->shortname = strrchr(p->name, '/')+1;
 499                         close(fd);
 500                         p->refcnt++;
 501                         return p;
 502                 }
 503         }
 504         map = map_library(fd, &temp_dso);
 505         close(fd);
 506         if (!map) return 0;
 507
 508         /* Allocate storage for the new DSO. When there is TLS, this
 509          * storage must include a reservation for all pre-existing
 510          * threads to obtain copies of both the new TLS, and an
 511          * extended DTV capable of storing an additional slot for
 512          * the newly-loaded DSO. */
 513         alloc_size = sizeof *p + strlen(pathname) + 1;
 514         if (runtime && temp_dso.tls_image) {
 515                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 516                         + sizeof(void *) * (tls_cnt+3);
 517                 n_th = __libc.threads_minus_1 + 1;
 518                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 519                 else alloc_size += n_th * per_th;
 520         }
 521         p = calloc(1, alloc_size);
 522         if (!p) {
 523                 munmap(map, map_len);
 524                 return 0;
 525         }
 526         memcpy(p, &temp_dso, sizeof temp_dso);
 527         decode_dyn(p);
 528         p->dev = st.st_dev;
 529         p->ino = st.st_ino;
 530         p->refcnt = 1;
 531         p->name = p->buf;
 532         strcpy(p->name, pathname);
 533         /* Add a shortname only if name arg was not an explicit pathname. */
 534         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 535         if (p->tls_image) {
 536                 if (runtime && !__pthread_self_init()) {
 537                         free(p);
 538                         munmap(map, map_len);
 539                         return 0;
 540                 }
 541                 p->tls_id = ++tls_cnt;
 542                 tls_align = MAXP2(tls_align, p->tls_align);
 543                 tls_offset += p->tls_size + p->tls_align - 1;
 544                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 545                         & (p->tls_align-1);
 546                 p->tls_offset = tls_offset;
 547                 p->new_dtv = (void *)(-sizeof(size_t) &
 548                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 549                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 550         }
 551
 552         tail->next = p;
 553         p->prev = tail;
 554         tail = p;
 555
 556         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, base);
 557
 558         return p;
 559 }
 560
 561 static void load_deps(struct dso *p)
 562 {
 563         size_t i, ndeps=0;
 564         struct dso ***deps = &p->deps, **tmp, *dep;
 565         for (; p; p=p->next) {
 566                 for (i=0; p->dynv[i]; i+=2) {
 567                         if (p->dynv[i] != DT_RPATH) continue;
 568                         r_path = (void *)(p->strings + p->dynv[i+1]);
 569                 }
 570                 for (i=0; p->dynv[i]; i+=2) {
 571                         if (p->dynv[i] != DT_NEEDED) continue;
 572                         dep = load_library(p->strings + p->dynv[i+1]);
 573                         if (!dep) {
 574                                 snprintf(errbuf, sizeof errbuf,
 575                                         "Error loading shared library %s: %m (needed by %s)",
 576                                         p->strings + p->dynv[i+1], p->name);
 577                                 if (runtime) longjmp(rtld_fail, 1);
 578                                 dprintf(2, "%s\n", errbuf);
 579                                 ldso_fail = 1;
 580                                 continue;
 581                         }
 582                         if (runtime) {
 583                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 584                                 if (!tmp) longjmp(rtld_fail, 1);
 585                                 tmp[ndeps++] = dep;
 586                                 tmp[ndeps] = 0;
 587                                 *deps = tmp;
 588                         }
 589                 }
 590                 r_path = 0;
 591         }
 592 }
 593
 594 static void load_preload(char *s)
 595 {
 596         int tmp;
 597         char *z;
 598         for (z=s; *z; s=z) {
 599                 for (   ; *s && isspace(*s); s++);
 600                 for (z=s; *z && !isspace(*z); z++);
 601                 tmp = *z;
 602                 *z = 0;
 603                 load_library(s);
 604                 *z = tmp;
 605         }
 606 }
 607
 608 static void make_global(struct dso *p)
 609 {
 610         for (; p; p=p->next) p->global = 1;
 611 }
 612
 613 static void reloc_all(struct dso *p)
 614 {
 615         size_t dyn[DYN_CNT] = {0};
 616         for (; p; p=p->next) {
 617                 if (p->relocated) continue;
 618                 decode_vec(p->dynv, dyn, DYN_CNT);
 619 #ifdef NEED_ARCH_RELOCS
 620                 do_arch_relocs(p, head);
 621 #endif
 622                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 623                         2+(dyn[DT_PLTREL]==DT_RELA));
 624                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 625                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 626                 p->relocated = 1;
 627         }
 628 }
 629
 630 static void free_all(struct dso *p)
 631 {
 632         struct dso *n;
 633         while (p) {
 634                 n = p->next;
 635                 if (p->map && p!=libc && p!=head) free(p);
 636                 p = n;
 637         }
 638 }
 639
 640 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
 641 {
 642         for (; cnt--; ph = (void *)((char *)ph + stride))
 643                 if (ph->p_type == PT_DYNAMIC)
 644                         return ph->p_vaddr;
 645         return 0;
 646 }
 647
 648 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
 649 {
 650         size_t min_addr = -1, max_addr = 0;
 651         for (; cnt--; ph = (void *)((char *)ph + stride)) {
 652                 if (ph->p_type != PT_LOAD) continue;
 653                 if (ph->p_vaddr < min_addr)
 654                         min_addr = ph->p_vaddr;
 655                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 656                         max_addr = ph->p_vaddr+ph->p_memsz;
 657         }
 658         min_addr &= -PAGE_SIZE;
 659         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 660         p->map = p->base + min_addr;
 661         p->map_len = max_addr - min_addr;
 662 }
 663
 664 static void do_fini()
 665 {
 666         struct dso *p;
 667         size_t dyn[DYN_CNT] = {0};
 668         for (p=fini_head; p; p=p->fini_next) {
 669                 if (!p->constructed) continue;
 670                 decode_vec(p->dynv, dyn, DYN_CNT);
 671                 ((void (*)(void))(p->base + dyn[DT_FINI]))();
 672         }
 673 }
 674
 675 static void do_init_fini(struct dso *p)
 676 {
 677         size_t dyn[DYN_CNT] = {0};
 678         int need_locking = __libc.threads_minus_1;
 679         /* Allow recursive calls that arise when a library calls
 680          * dlopen from one of its constructors, but block any
 681          * other threads until all ctors have finished. */
 682         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 683         for (; p; p=p->prev) {
 684                 if (p->constructed) continue;
 685                 p->constructed = 1;
 686                 decode_vec(p->dynv, dyn, DYN_CNT);
 687                 if (dyn[0] & (1<<DT_FINI)) {
 688                         p->fini_next = fini_head;
 689                         fini_head = p;
 690                 }
 691                 if (dyn[0] & (1<<DT_INIT))
 692                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 693         }
 694         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 695 }
 696
 697 void _dl_debug_state(void)
 698 {
 699 }
 700
 701 void *__copy_tls(unsigned char *mem)
 702 {
 703         pthread_t td;
 704         struct dso *p;
 705
 706         if (!tls_cnt) return mem;
 707
 708         void **dtv = (void *)mem;
 709         dtv[0] = (void *)tls_cnt;
 710
 711         mem += __libc.tls_size - sizeof(struct pthread);
 712         mem -= (uintptr_t)mem & (tls_align-1);
 713         mem -= tls_start;
 714         td = (pthread_t)mem;
 715
 716         for (p=head; p; p=p->next) {
 717                 if (!p->tls_id) continue;
 718                 dtv[p->tls_id] = mem - p->tls_offset;
 719                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 720         }
 721         td->dtv = dtv;
 722         return td;
 723 }
 724
 725 void *__tls_get_addr(size_t *v)
 726 {
 727         pthread_t self = __pthread_self();
 728         if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
 729                 return (char *)self->dtv[v[0]]+v[1];
 730
 731         /* Block signals to make accessing new TLS async-signal-safe */
 732         sigset_t set;
 733         pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
 734         if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
 735                 pthread_sigmask(SIG_SETMASK, &set, 0);
 736                 return (char *)self->dtv[v[0]]+v[1];
 737         }
 738
 739         /* This is safe without any locks held because, if the caller
 740          * is able to request the Nth entry of the DTV, the DSO list
 741          * must be valid at least that far out and it was synchronized
 742          * at program startup or by an already-completed call to dlopen. */
 743         struct dso *p;
 744         for (p=head; p->tls_id != v[0]; p=p->next);
 745
 746         /* Get new DTV space from new DSO if needed */
 747         if (!self->dtv || v[0] > (size_t)self->dtv[0]) {
 748                 void **newdtv = p->new_dtv +
 749                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
 750                 if (self->dtv) memcpy(newdtv, self->dtv,
 751                         ((size_t)self->dtv[0]+1) * sizeof(void *));
 752                 newdtv[0] = (void *)v[0];
 753                 self->dtv = newdtv;
 754         }
 755
 756         /* Get new TLS memory from new DSO */
 757         unsigned char *mem = p->new_tls +
 758                 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
 759         mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
 760         self->dtv[v[0]] = mem;
 761         memcpy(mem, p->tls_image, p->tls_len);
 762         pthread_sigmask(SIG_SETMASK, &set, 0);
 763         return mem + v[1];
 764 }
 765
 766 static void update_tls_size()
 767 {
 768         size_t below_tp = (1+tls_cnt) * sizeof(void *) + tls_offset;
 769         size_t above_tp = sizeof(struct pthread) + tls_start + tls_align;
 770         __libc.tls_size = ALIGN(below_tp + above_tp, tls_align);
 771 }
 772
 773 void *__dynlink(int argc, char **argv)
 774 {
 775         size_t aux[AUX_CNT] = {0};
 776         size_t i;
 777         Phdr *phdr;
 778         Ehdr *ehdr;
 779         static struct dso builtin_dsos[3];
 780         struct dso *const app = builtin_dsos+0;
 781         struct dso *const lib = builtin_dsos+1;
 782         struct dso *const vdso = builtin_dsos+2;
 783         char *env_preload=0;
 784         size_t vdso_base;
 785
 786         /* Find aux vector just past environ[] */
 787         for (i=argc+1; argv[i]; i++)
 788                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
 789                         env_path = argv[i]+16;
 790                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
 791                         env_preload = argv[i]+11;
 792         auxv = (void *)(argv+i+1);
 793
 794         decode_vec(auxv, aux, AUX_CNT);
 795
 796         /* Only trust user/env if kernel says we're not suid/sgid */
 797         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
 798           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
 799                 env_path = 0;
 800                 env_preload = 0;
 801         }
 802
 803         /* If the dynamic linker was invoked as a program itself, AT_BASE
 804          * will not be set. In that case, we assume the base address is
 805          * the start of the page containing the PHDRs; I don't know any
 806          * better approach... */
 807         if (!aux[AT_BASE]) {
 808                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
 809                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
 810         }
 811
 812         /* The dynamic linker load address is passed by the kernel
 813          * in the AUX vector, so this is easy. */
 814         lib->base = (void *)aux[AT_BASE];
 815         lib->name = lib->shortname = "libc.so";
 816         lib->global = 1;
 817         ehdr = (void *)lib->base;
 818         find_map_range((void *)(aux[AT_BASE]+ehdr->e_phoff),
 819                 ehdr->e_phnum, ehdr->e_phentsize, lib);
 820         lib->dynv = (void *)(lib->base + find_dyn(
 821                 (void *)(aux[AT_BASE]+ehdr->e_phoff),
 822                 ehdr->e_phnum, ehdr->e_phentsize));
 823         decode_dyn(lib);
 824
 825         if (aux[AT_PHDR]) {
 826                 size_t interp_off = 0;
 827                 size_t tls_image = 0;
 828                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
 829                 phdr = (void *)aux[AT_PHDR];
 830                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
 831                         if (phdr->p_type == PT_PHDR)
 832                                 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
 833                         else if (phdr->p_type == PT_INTERP)
 834                                 interp_off = (size_t)phdr->p_vaddr;
 835                         else if (phdr->p_type == PT_TLS) {
 836                                 tls_image = phdr->p_vaddr;
 837                                 app->tls_len = phdr->p_filesz;
 838                                 app->tls_size = phdr->p_memsz;
 839                                 app->tls_align = phdr->p_align;
 840                         }
 841                 }
 842                 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
 843                 if (interp_off) lib->name = (char *)app->base + interp_off;
 844                 app->name = argv[0];
 845                 app->dynv = (void *)(app->base + find_dyn(
 846                         (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
 847                 find_map_range((void *)aux[AT_PHDR],
 848                         aux[AT_PHNUM], aux[AT_PHENT], app);
 849         } else {
 850                 int fd;
 851                 char *ldname = argv[0];
 852                 size_t dyno, l = strlen(ldname);
 853                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
 854                 *argv++ = (void *)-1;
 855                 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
 856                 if (!argv[0]) {
 857                         dprintf(2, "musl libc/dynamic program loader\n");
 858                         dprintf(2, "usage: %s pathname%s\n", ldname,
 859                                 ldd_mode ? "" : " [args]");
 860                         _exit(1);
 861                 }
 862                 fd = open(argv[0], O_RDONLY);
 863                 if (fd < 0) {
 864                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
 865                         _exit(1);
 866                 }
 867                 runtime = 1;
 868                 ehdr = (void *)map_library(fd, app);
 869                 if (!ehdr) {
 870                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
 871                         _exit(1);
 872                 }
 873                 runtime = 0;
 874                 close(fd);
 875                 lib->name = ldname;
 876                 app->name = argv[0];
 877                 aux[AT_ENTRY] = ehdr->e_entry;
 878         }
 879         if (app->tls_size) {
 880                 app->tls_id = tls_cnt = 1;
 881                 tls_offset = app->tls_offset = app->tls_size;
 882                 tls_start = -((uintptr_t)app->tls_image + app->tls_size)
 883                         & (app->tls_align-1);
 884                 tls_align = MAXP2(tls_align, app->tls_align);
 885         }
 886         app->global = 1;
 887         app->constructed = 1;
 888         decode_dyn(app);
 889
 890         /* Attach to vdso, if provided by the kernel */
 891         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
 892                 ehdr = (void *)vdso_base;
 893                 phdr = (void *)(vdso_base + ehdr->e_phoff);
 894                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
 895                         if (phdr->p_type == PT_DYNAMIC)
 896                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
 897                         if (phdr->p_type == PT_LOAD)
 898                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
 899                 }
 900                 vdso->name = vdso->shortname = "linux-gate.so.1";
 901                 vdso->global = 1;
 902                 decode_dyn(vdso);
 903                 vdso->prev = lib;
 904                 lib->next = vdso;
 905         }
 906
 907         /* Initial dso chain consists only of the app. We temporarily
 908          * append the dynamic linker/libc so we can relocate it, then
 909          * restore the initial chain in preparation for loading third
 910          * party libraries (preload/needed). */
 911         head = tail = app;
 912         libc = lib;
 913         app->next = lib;
 914         reloc_all(lib);
 915         app->next = 0;
 916
 917         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
 918
 919         /* Donate unused parts of app and library mapping to malloc */
 920         reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
 921         ehdr = (void *)lib->base;
 922         reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
 923                 ehdr->e_phentsize, ehdr->e_phnum);
 924
 925         /* Load preload/needed libraries, add their symbols to the global
 926          * namespace, and perform all remaining relocations. The main
 927          * program must be relocated LAST since it may contain copy
 928          * relocations which depend on libraries' relocations. */
 929         if (env_preload) load_preload(env_preload);
 930         load_deps(app);
 931         make_global(app);
 932
 933         reloc_all(app->next);
 934         reloc_all(app);
 935
 936         update_tls_size();
 937         if (tls_cnt) {
 938                 struct dso *p;
 939                 void *mem = mmap(0, __libc.tls_size, PROT_READ|PROT_WRITE,
 940                         MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
 941                 if (mem==MAP_FAILED ||
 942                     !__install_initial_tls(__copy_tls(mem))) {
 943                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
 944                                 argv[0], __libc.tls_size);
 945                         _exit(127);
 946                 }
 947         }
 948
 949         if (ldso_fail) _exit(127);
 950         if (ldd_mode) _exit(0);
 951
 952         /* Switch to runtime mode: any further failures in the dynamic
 953          * linker are a reportable failure rather than a fatal startup
 954          * error. If the dynamic loader (dlopen) will not be used, free
 955          * all memory used by the dynamic linker. */
 956         runtime = 1;
 957
 958 #ifndef DYNAMIC_IS_RO
 959         for (i=0; app->dynv[i]; i+=2)
 960                 if (app->dynv[i]==DT_DEBUG)
 961                         app->dynv[i+1] = (size_t)&debug;
 962 #endif
 963         debug.ver = 1;
 964         debug.bp = _dl_debug_state;
 965         debug.head = head;
 966         debug.base = lib->base;
 967         debug.state = 0;
 968         _dl_debug_state();
 969
 970         if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
 971
 972         atexit(do_fini);
 973         do_init_fini(tail);
 974
 975         errno = 0;
 976         return (void *)aux[AT_ENTRY];
 977 }
 978
 979 void *dlopen(const char *file, int mode)
 980 {
 981         struct dso *volatile p, *orig_tail, *next;
 982         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
 983         size_t i;
 984         int cs;
 985
 986         if (!file) return head;
 987
 988         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
 989         pthread_rwlock_wrlock(&lock);
 990         __inhibit_ptc();
 991
 992         p = 0;
 993         orig_tls_cnt = tls_cnt;
 994         orig_tls_offset = tls_offset;
 995         orig_tls_align = tls_align;
 996         orig_tail = tail;
 997
 998         if (setjmp(rtld_fail)) {
 999                 /* Clean up anything new that was (partially) loaded */
1000                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1001                         if (p->deps[i]->global < 0)
1002                                 p->deps[i]->global = 0;
1003                 for (p=orig_tail->next; p; p=next) {
1004                         next = p->next;
1005                         munmap(p->map, p->map_len);
1006                         free(p->deps);
1007                         free(p);
1008                 }
1009                 tls_cnt = orig_tls_cnt;
1010                 tls_offset = orig_tls_offset;
1011                 tls_align = orig_tls_align;
1012                 tail = orig_tail;
1013                 tail->next = 0;
1014                 p = 0;
1015                 errflag = 1;
1016                 goto end;
1017         } else p = load_library(file);
1018
1019         if (!p) {
1020                 snprintf(errbuf, sizeof errbuf,
1021                         "Error loading shared library %s: %m", file);
1022                 errflag = 1;
1023                 goto end;
1024         }
1025
1026         /* First load handling */
1027         if (!p->deps) {
1028                 load_deps(p);
1029                 if (p->deps) for (i=0; p->deps[i]; i++)
1030                         if (!p->deps[i]->global)
1031                                 p->deps[i]->global = -1;
1032                 if (!p->global) p->global = -1;
1033                 reloc_all(p);
1034                 if (p->deps) for (i=0; p->deps[i]; i++)
1035                         if (p->deps[i]->global < 0)
1036                                 p->deps[i]->global = 0;
1037                 if (p->global < 0) p->global = 0;
1038         }
1039
1040         if (mode & RTLD_GLOBAL) {
1041                 if (p->deps) for (i=0; p->deps[i]; i++)
1042                         p->deps[i]->global = 1;
1043                 p->global = 1;
1044         }
1045
1046         update_tls_size();
1047
1048         if (ssp_used) __init_ssp(auxv);
1049
1050         _dl_debug_state();
1051         orig_tail = tail;
1052 end:
1053         __release_ptc();
1054         pthread_rwlock_unlock(&lock);
1055         if (p) do_init_fini(orig_tail);
1056         pthread_setcancelstate(cs, 0);
1057         return p;
1058 }
1059
1060 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1061 {
1062         size_t i;
1063         uint32_t h = 0, gh = 0;
1064         Sym *sym;
1065         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1066                 if (p == RTLD_NEXT) {
1067                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1068                         if (!p) p=head;
1069                 }
1070                 struct symdef def = find_sym(p->next, s, 0);
1071                 if (!def.sym) goto failed;
1072                 return def.dso->base + def.sym->st_value;
1073         }
1074         if (p->ghashtab) {
1075                 gh = gnu_hash(s);
1076                 sym = gnu_lookup(s, gh, p);
1077         } else {
1078                 h = sysv_hash(s);
1079                 sym = sysv_lookup(s, h, p);
1080         }
1081         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1082                 return p->base + sym->st_value;
1083         if (p->deps) for (i=0; p->deps[i]; i++) {
1084                 if (p->deps[i]->ghashtab) {
1085                         if (!gh) gh = gnu_hash(s);
1086                         sym = gnu_lookup(s, gh, p->deps[i]);
1087                 } else {
1088                         if (!h) h = sysv_hash(s);
1089                         sym = sysv_lookup(s, h, p->deps[i]);
1090                 }
1091                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1092                         return p->deps[i]->base + sym->st_value;
1093         }
1094 failed:
1095         errflag = 1;
1096         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1097         return 0;
1098 }
1099
1100 int __dladdr(void *addr, Dl_info *info)
1101 {
1102         struct dso *p;
1103         Sym *sym;
1104         uint32_t nsym;
1105         char *strings;
1106         size_t i;
1107         void *best = 0;
1108         char *bestname;
1109
1110         pthread_rwlock_rdlock(&lock);
1111         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1112         pthread_rwlock_unlock(&lock);
1113
1114         if (!p) return 0;
1115
1116         sym = p->syms;
1117         strings = p->strings;
1118         if (p->hashtab) {
1119                 nsym = p->hashtab[1];
1120         } else {
1121                 uint32_t *buckets;
1122                 uint32_t *hashval;
1123                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1124                 sym += p->ghashtab[1];
1125                 for (i = 0; i < p->ghashtab[0]; i++) {
1126                         if (buckets[i] > nsym)
1127                                 nsym = buckets[i];
1128                 }
1129                 if (nsym) {
1130                         nsym -= p->ghashtab[1];
1131                         hashval = buckets + p->ghashtab[0] + nsym;
1132                         do nsym++;
1133                         while (!(*hashval++ & 1));
1134                 }
1135         }
1136
1137         for (; nsym; nsym--, sym++) {
1138                 if (sym->st_shndx && sym->st_value
1139                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1140                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1141                         void *symaddr = p->base + sym->st_value;
1142                         if (symaddr > addr || symaddr < best)
1143                                 continue;
1144                         best = symaddr;
1145                         bestname = strings + sym->st_name;
1146                         if (addr == symaddr)
1147                                 break;
1148                 }
1149         }
1150
1151         if (!best) return 0;
1152
1153         info->dli_fname = p->name;
1154         info->dli_fbase = p->base;
1155         info->dli_sname = bestname;
1156         info->dli_saddr = best;
1157
1158         return 1;
1159 }
1160
1161 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1162 {
1163         void *res;
1164         pthread_rwlock_rdlock(&lock);
1165         res = do_dlsym(p, s, ra);
1166         pthread_rwlock_unlock(&lock);
1167         return res;
1168 }
1169 #else
1170 void *dlopen(const char *file, int mode)
1171 {
1172         return 0;
1173 }
1174 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1175 {
1176         return 0;
1177 }
1178 int __dladdr (void *addr, Dl_info *info)
1179 {
1180         return 0;
1181 }
1182 #endif
1183
1184 char *dlerror()
1185 {
1186         if (!errflag) return 0;
1187         errflag = 0;
1188         return errbuf;
1189 }
1190
1191 int dlclose(void *p)
1192 {
1193         return 0;
1194 }