src/ldso/dynlink.c

   1 #define _GNU_SOURCE
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <stdarg.h>
   5 #include <stddef.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <stdint.h>
   9 #include <elf.h>
  10 #include <sys/mman.h>
  11 #include <limits.h>
  12 #include <fcntl.h>
  13 #include <sys/stat.h>
  14 #include <errno.h>
  15 #include <link.h>
  16 #include <setjmp.h>
  17 #include <pthread.h>
  18 #include <ctype.h>
  19 #include <dlfcn.h>
  20 #include "pthread_impl.h"
  21 #include "libc.h"
  22 #include "dynlink.h"
  23
  24 static void error(const char *, ...);
  25
  26 #ifdef SHARED
  27
  28 #define MAXP2(a,b) (-(-(a)&-(b)))
  29 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  30
  31 struct debug {
  32         int ver;
  33         void *head;
  34         void (*bp)(void);
  35         int state;
  36         void *base;
  37 };
  38
  39 struct td_index {
  40         size_t args[2];
  41         struct td_index *next;
  42 };
  43
  44 struct dso {
  45         unsigned char *base;
  46         char *name;
  47         size_t *dynv;
  48         struct dso *next, *prev;
  49
  50         Phdr *phdr;
  51         int phnum;
  52         size_t phentsize;
  53         int refcnt;
  54         Sym *syms;
  55         uint32_t *hashtab;
  56         uint32_t *ghashtab;
  57         int16_t *versym;
  58         char *strings;
  59         unsigned char *map;
  60         size_t map_len;
  61         dev_t dev;
  62         ino_t ino;
  63         signed char global;
  64         char relocated;
  65         char constructed;
  66         char kernel_mapped;
  67         struct dso **deps, *needed_by;
  68         char *rpath_orig, *rpath;
  69         void *tls_image;
  70         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  71         size_t relro_start, relro_end;
  72         void **new_dtv;
  73         unsigned char *new_tls;
  74         volatile int new_dtv_idx, new_tls_idx;
  75         struct td_index *td_index;
  76         struct dso *fini_next;
  77         char *shortname;
  78         char buf[];
  79 };
  80
  81 struct symdef {
  82         Sym *sym;
  83         struct dso *dso;
  84 };
  85
  86 int __init_tp(void *);
  87 void __init_libc(char **, char *);
  88
  89 const char *__libc_get_version(void);
  90
  91 static struct builtin_tls {
  92         char c;
  93         struct pthread pt;
  94         void *space[16];
  95 } builtin_tls[1];
  96 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
  97
  98 #define ADDEND_LIMIT 4096
  99 static size_t *saved_addends, *apply_addends_to;
 100
 101 static struct dso ldso;
 102 static struct dso *head, *tail, *fini_head;
 103 static char *env_path, *sys_path;
 104 static unsigned long long gencnt;
 105 static int runtime;
 106 static int ldd_mode;
 107 static int ldso_fail;
 108 static int noload;
 109 static jmp_buf *rtld_fail;
 110 static pthread_rwlock_t lock;
 111 static struct debug debug;
 112 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
 113 static size_t static_tls_cnt;
 114 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 115
 116 struct debug *_dl_debug_addr = &debug;
 117
 118 static int dl_strcmp(const char *l, const char *r)
 119 {
 120         for (; *l==*r && *l; l++, r++);
 121         return *(unsigned char *)l - *(unsigned char *)r;
 122 }
 123 #define strcmp(l,r) dl_strcmp(l,r)
 124
 125 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 126 {
 127         size_t i;
 128         for (i=0; i<cnt; i++) a[i] = 0;
 129         for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
 130                 a[0] |= 1UL<<v[0];
 131                 a[v[0]] = v[1];
 132         }
 133 }
 134
 135 static int search_vec(size_t *v, size_t *r, size_t key)
 136 {
 137         for (; v[0]!=key; v+=2)
 138                 if (!v[0]) return 0;
 139         *r = v[1];
 140         return 1;
 141 }
 142
 143 static uint32_t sysv_hash(const char *s0)
 144 {
 145         const unsigned char *s = (void *)s0;
 146         uint_fast32_t h = 0;
 147         while (*s) {
 148                 h = 16*h + *s++;
 149                 h ^= h>>24 & 0xf0;
 150         }
 151         return h & 0xfffffff;
 152 }
 153
 154 static uint32_t gnu_hash(const char *s0)
 155 {
 156         const unsigned char *s = (void *)s0;
 157         uint_fast32_t h = 5381;
 158         for (; *s; s++)
 159                 h += h*32 + *s;
 160         return h;
 161 }
 162
 163 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 164 {
 165         size_t i;
 166         Sym *syms = dso->syms;
 167         uint32_t *hashtab = dso->hashtab;
 168         char *strings = dso->strings;
 169         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 170                 if ((!dso->versym || dso->versym[i] >= 0)
 171                     && (!strcmp(s, strings+syms[i].st_name)))
 172                         return syms+i;
 173         }
 174         return 0;
 175 }
 176
 177 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 178 {
 179         uint32_t *hashtab = dso->ghashtab;
 180         uint32_t nbuckets = hashtab[0];
 181         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 182         uint32_t i = buckets[h1 % nbuckets];
 183
 184         if (!i) return 0;
 185
 186         uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
 187
 188         for (h1 |= 1; ; i++) {
 189                 uint32_t h2 = *hashval++;
 190                 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
 191                     && !strcmp(s, dso->strings + dso->syms[i].st_name))
 192                         return dso->syms+i;
 193                 if (h2 & 1) break;
 194         }
 195
 196         return 0;
 197 }
 198
 199 static Sym *gnu_lookup_filtered(const char *s, uint32_t h1, struct dso *dso, uint32_t fofs, size_t fmask)
 200 {
 201         uint32_t *hashtab = dso->ghashtab;
 202         const size_t *bloomwords = (const void *)(hashtab+4);
 203         size_t f = bloomwords[fofs & (hashtab[2]-1)];
 204         if (!(f & fmask)) return 0;
 205
 206         f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
 207         if (!(f & 1)) return 0;
 208
 209         return gnu_lookup(s, h1, dso);
 210 }
 211
 212 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 213 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 214
 215 #ifndef ARCH_SYM_REJECT_UND
 216 #define ARCH_SYM_REJECT_UND(s) 0
 217 #endif
 218
 219 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 220 {
 221         uint32_t h = 0, gh, gho;
 222         size_t ghm = 0;
 223         struct symdef def = {0};
 224         for (; dso; dso=dso->next) {
 225                 Sym *sym;
 226                 if (!dso->global) continue;
 227                 if (dso->ghashtab) {
 228                         if (!ghm) {
 229                                 gh = gnu_hash(s);
 230                                 int maskbits = 8 * sizeof ghm;
 231                                 gho = gh / maskbits;
 232                                 ghm = 1ul << gh % maskbits;
 233                         }
 234                         sym = gnu_lookup_filtered(s, gh, dso, gho, ghm);
 235                 } else {
 236                         if (!h) h = sysv_hash(s);
 237                         sym = sysv_lookup(s, h, dso);
 238                 }
 239                 if (!sym) continue;
 240                 if (!sym->st_shndx)
 241                         if (need_def || (sym->st_info&0xf) == STT_TLS
 242                             || ARCH_SYM_REJECT_UND(sym))
 243                                 continue;
 244                 if (!sym->st_value)
 245                         if ((sym->st_info&0xf) != STT_TLS)
 246                                 continue;
 247                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 248                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 249
 250                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 251                 def.sym = sym;
 252                 def.dso = dso;
 253                 if (sym->st_info>>4 == STB_GLOBAL) break;
 254         }
 255         return def;
 256 }
 257
 258 __attribute__((__visibility__("hidden")))
 259 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
 260
 261 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 262 {
 263         unsigned char *base = dso->base;
 264         Sym *syms = dso->syms;
 265         char *strings = dso->strings;
 266         Sym *sym;
 267         const char *name;
 268         void *ctx;
 269         int type;
 270         int sym_index;
 271         struct symdef def;
 272         size_t *reloc_addr;
 273         size_t sym_val;
 274         size_t tls_val;
 275         size_t addend;
 276         int skip_relative = 0, reuse_addends = 0, save_slot = 0;
 277
 278         if (dso == &ldso) {
 279                 /* Only ldso's REL table needs addend saving/reuse. */
 280                 if (rel == apply_addends_to)
 281                         reuse_addends = 1;
 282                 skip_relative = 1;
 283         }
 284
 285         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 286                 if (skip_relative && IS_RELATIVE(rel[1])) continue;
 287                 type = R_TYPE(rel[1]);
 288                 if (type == REL_NONE) continue;
 289                 sym_index = R_SYM(rel[1]);
 290                 reloc_addr = (void *)(base + rel[0]);
 291                 if (sym_index) {
 292                         sym = syms + sym_index;
 293                         name = strings + sym->st_name;
 294                         ctx = type==REL_COPY ? head->next : head;
 295                         def = find_sym(ctx, name, type==REL_PLT);
 296                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 297                             || sym->st_info>>4 != STB_WEAK)) {
 298                                 error("Error relocating %s: %s: symbol not found",
 299                                         dso->name, name);
 300                                 if (runtime) longjmp(*rtld_fail, 1);
 301                                 continue;
 302                         }
 303                 } else {
 304                         sym = 0;
 305                         def.sym = 0;
 306                         def.dso = dso;
 307                 }
 308
 309                 if (stride > 2) {
 310                         addend = rel[2];
 311                 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
 312                         addend = 0;
 313                 } else if (reuse_addends) {
 314                         /* Save original addend in stage 2 where the dso
 315                          * chain consists of just ldso; otherwise read back
 316                          * saved addend since the inline one was clobbered. */
 317                         if (head==&ldso)
 318                                 saved_addends[save_slot] = *reloc_addr;
 319                         addend = saved_addends[save_slot++];
 320                 } else {
 321                         addend = *reloc_addr;
 322                 }
 323
 324                 sym_val = def.sym ? (size_t)def.dso->base+def.sym->st_value : 0;
 325                 tls_val = def.sym ? def.sym->st_value : 0;
 326
 327                 switch(type) {
 328                 case REL_NONE:
 329                         break;
 330                 case REL_OFFSET:
 331                         addend -= (size_t)reloc_addr;
 332                 case REL_SYMBOLIC:
 333                 case REL_GOT:
 334                 case REL_PLT:
 335                         *reloc_addr = sym_val + addend;
 336                         break;
 337                 case REL_RELATIVE:
 338                         *reloc_addr = (size_t)base + addend;
 339                         break;
 340                 case REL_SYM_OR_REL:
 341                         if (sym) *reloc_addr = sym_val + addend;
 342                         else *reloc_addr = (size_t)base + addend;
 343                         break;
 344                 case REL_COPY:
 345                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 346                         break;
 347                 case REL_OFFSET32:
 348                         *(uint32_t *)reloc_addr = sym_val + addend
 349                                 - (size_t)reloc_addr;
 350                         break;
 351                 case REL_DTPMOD:
 352                         *reloc_addr = def.dso->tls_id;
 353                         break;
 354                 case REL_DTPOFF:
 355                         *reloc_addr = tls_val + addend - DTP_OFFSET;
 356                         break;
 357 #ifdef TLS_ABOVE_TP
 358                 case REL_TPOFF:
 359                         *reloc_addr = tls_val + def.dso->tls_offset + TPOFF_K + addend;
 360                         break;
 361 #else
 362                 case REL_TPOFF:
 363                         *reloc_addr = tls_val - def.dso->tls_offset + addend;
 364                         break;
 365                 case REL_TPOFF_NEG:
 366                         *reloc_addr = def.dso->tls_offset - tls_val + addend;
 367                         break;
 368 #endif
 369                 case REL_TLSDESC:
 370                         if (stride<3) addend = reloc_addr[1];
 371                         if (runtime && def.dso->tls_id >= static_tls_cnt) {
 372                                 struct td_index *new = malloc(sizeof *new);
 373                                 if (!new) {
 374                                         error(
 375                                         "Error relocating %s: cannot allocate TLSDESC for %s",
 376                                         dso->name, sym ? name : "(local)" );
 377                                         longjmp(*rtld_fail, 1);
 378                                 }
 379                                 new->next = dso->td_index;
 380                                 dso->td_index = new;
 381                                 new->args[0] = def.dso->tls_id;
 382                                 new->args[1] = tls_val + addend;
 383                                 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
 384                                 reloc_addr[1] = (size_t)new;
 385                         } else {
 386                                 reloc_addr[0] = (size_t)__tlsdesc_static;
 387 #ifdef TLS_ABOVE_TP
 388                                 reloc_addr[1] = tls_val + def.dso->tls_offset
 389                                         + TPOFF_K + addend;
 390 #else
 391                                 reloc_addr[1] = tls_val - def.dso->tls_offset
 392                                         + addend;
 393 #endif
 394                         }
 395                         break;
 396                 default:
 397                         error("Error relocating %s: unsupported relocation type %d",
 398                                 dso->name, type);
 399                         if (runtime) longjmp(*rtld_fail, 1);
 400                         continue;
 401                 }
 402         }
 403 }
 404
 405 /* A huge hack: to make up for the wastefulness of shared libraries
 406  * needing at least a page of dirty memory even if they have no global
 407  * data, we reclaim the gaps at the beginning and end of writable maps
 408  * and "donate" them to the heap by setting up minimal malloc
 409  * structures and then freeing them. */
 410
 411 static void reclaim(struct dso *dso, size_t start, size_t end)
 412 {
 413         size_t *a, *z;
 414         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 415         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 416         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 417         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 418         if (start>end || end-start < 4*sizeof(size_t)) return;
 419         a = (size_t *)(dso->base + start);
 420         z = (size_t *)(dso->base + end);
 421         a[-2] = 1;
 422         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 423         z[1] = 1;
 424         free(a);
 425 }
 426
 427 static void reclaim_gaps(struct dso *dso)
 428 {
 429         Phdr *ph = dso->phdr;
 430         size_t phcnt = dso->phnum;
 431
 432         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 433                 if (ph->p_type!=PT_LOAD) continue;
 434                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 435                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 436                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 437                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 438         }
 439 }
 440
 441 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
 442 {
 443         char *q = mmap(p, n, prot, flags, fd, off);
 444         if (q != MAP_FAILED || errno != EINVAL) return q;
 445         /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
 446         if (flags & MAP_ANONYMOUS) {
 447                 memset(p, 0, n);
 448                 return p;
 449         }
 450         ssize_t r;
 451         if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
 452         for (q=p; n; q+=r, off+=r, n-=r) {
 453                 r = read(fd, q, n);
 454                 if (r < 0 && errno != EINTR) return MAP_FAILED;
 455                 if (!r) {
 456                         memset(q, 0, n);
 457                         break;
 458                 }
 459         }
 460         return p;
 461 }
 462
 463 static void *map_library(int fd, struct dso *dso)
 464 {
 465         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 466         void *allocated_buf=0;
 467         size_t phsize;
 468         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 469         size_t this_min, this_max;
 470         off_t off_start;
 471         Ehdr *eh;
 472         Phdr *ph, *ph0;
 473         unsigned prot;
 474         unsigned char *map=MAP_FAILED, *base;
 475         size_t dyn=0;
 476         size_t tls_image=0;
 477         size_t i;
 478
 479         ssize_t l = read(fd, buf, sizeof buf);
 480         eh = buf;
 481         if (l<0) return 0;
 482         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 483                 goto noexec;
 484         phsize = eh->e_phentsize * eh->e_phnum;
 485         if (phsize > sizeof buf - sizeof *eh) {
 486                 allocated_buf = malloc(phsize);
 487                 if (!allocated_buf) return 0;
 488                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 489                 if (l < 0) goto error;
 490                 if (l != phsize) goto noexec;
 491                 ph = ph0 = allocated_buf;
 492         } else if (eh->e_phoff + phsize > l) {
 493                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 494                 if (l < 0) goto error;
 495                 if (l != phsize) goto noexec;
 496                 ph = ph0 = (void *)(buf + 1);
 497         } else {
 498                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 499         }
 500         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 501                 if (ph->p_type == PT_DYNAMIC) {
 502                         dyn = ph->p_vaddr;
 503                 } else if (ph->p_type == PT_TLS) {
 504                         tls_image = ph->p_vaddr;
 505                         dso->tls_align = ph->p_align;
 506                         dso->tls_len = ph->p_filesz;
 507                         dso->tls_size = ph->p_memsz;
 508                 } else if (ph->p_type == PT_GNU_RELRO) {
 509                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 510                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 511                 }
 512                 if (ph->p_type != PT_LOAD) continue;
 513                 if (ph->p_vaddr < addr_min) {
 514                         addr_min = ph->p_vaddr;
 515                         off_start = ph->p_offset;
 516                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 517                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 518                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 519                 }
 520                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 521                         addr_max = ph->p_vaddr+ph->p_memsz;
 522                 }
 523         }
 524         if (!dyn) goto noexec;
 525         addr_max += PAGE_SIZE-1;
 526         addr_max &= -PAGE_SIZE;
 527         addr_min &= -PAGE_SIZE;
 528         off_start &= -PAGE_SIZE;
 529         map_len = addr_max - addr_min + off_start;
 530         /* The first time, we map too much, possibly even more than
 531          * the length of the file. This is okay because we will not
 532          * use the invalid part; we just need to reserve the right
 533          * amount of virtual address space to map over later. */
 534         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 535         if (map==MAP_FAILED) goto error;
 536         /* If the loaded file is not relocatable and the requested address is
 537          * not available, then the load operation must fail. */
 538         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 539                 errno = EBUSY;
 540                 goto error;
 541         }
 542         base = map - addr_min;
 543         dso->phdr = 0;
 544         dso->phnum = 0;
 545         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 546                 if (ph->p_type != PT_LOAD) continue;
 547                 /* Check if the programs headers are in this load segment, and
 548                  * if so, record the address for use by dl_iterate_phdr. */
 549                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 550                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 551                         dso->phdr = (void *)(base + ph->p_vaddr
 552                                 + (eh->e_phoff-ph->p_offset));
 553                         dso->phnum = eh->e_phnum;
 554                         dso->phentsize = eh->e_phentsize;
 555                 }
 556                 /* Reuse the existing mapping for the lowest-address LOAD */
 557                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 558                 this_min = ph->p_vaddr & -PAGE_SIZE;
 559                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 560                 off_start = ph->p_offset & -PAGE_SIZE;
 561                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 562                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 563                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 564                 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 565                         goto error;
 566                 if (ph->p_memsz > ph->p_filesz) {
 567                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 568                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 569                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 570                         if (pgbrk-(size_t)base < this_max && mmap_fixed((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED)
 571                                 goto error;
 572                 }
 573         }
 574         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 575                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 576                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
 577                             && errno != ENOSYS)
 578                                 goto error;
 579                         break;
 580                 }
 581         dso->map = map;
 582         dso->map_len = map_len;
 583         dso->base = base;
 584         dso->dynv = (void *)(base+dyn);
 585         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 586         if (!runtime) reclaim_gaps(dso);
 587         free(allocated_buf);
 588         return map;
 589 noexec:
 590         errno = ENOEXEC;
 591 error:
 592         if (map!=MAP_FAILED) munmap(map, map_len);
 593         free(allocated_buf);
 594         return 0;
 595 }
 596
 597 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 598 {
 599         size_t l;
 600         int fd;
 601         for (;;) {
 602                 s += strspn(s, ":\n");
 603                 l = strcspn(s, ":\n");
 604                 if (l-1 >= INT_MAX) return -1;
 605                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
 606                         if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 607                         switch (errno) {
 608                         case ENOENT:
 609                         case ENOTDIR:
 610                         case EACCES:
 611                         case ENAMETOOLONG:
 612                                 break;
 613                         default:
 614                                 /* Any negative value but -1 will inhibit
 615                                  * futher path search. */
 616                                 return -2;
 617                         }
 618                 }
 619                 s += l;
 620         }
 621 }
 622
 623 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 624 {
 625         size_t n, l;
 626         const char *s, *t, *origin;
 627         char *d;
 628         if (p->rpath || !p->rpath_orig) return 0;
 629         if (!strchr(p->rpath_orig, '$')) {
 630                 p->rpath = p->rpath_orig;
 631                 return 0;
 632         }
 633         n = 0;
 634         s = p->rpath_orig;
 635         while ((t=strchr(s, '$'))) {
 636                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 637                         return 0;
 638                 s = t+1;
 639                 n++;
 640         }
 641         if (n > SSIZE_MAX/PATH_MAX) return 0;
 642
 643         if (p->kernel_mapped) {
 644                 /* $ORIGIN searches cannot be performed for the main program
 645                  * when it is suid/sgid/AT_SECURE. This is because the
 646                  * pathname is under the control of the caller of execve.
 647                  * For libraries, however, $ORIGIN can be processed safely
 648                  * since the library's pathname came from a trusted source
 649                  * (either system paths or a call to dlopen). */
 650                 if (libc.secure)
 651                         return 0;
 652                 l = readlink("/proc/self/exe", buf, buf_size);
 653                 if (l == -1) switch (errno) {
 654                 case ENOENT:
 655                 case ENOTDIR:
 656                 case EACCES:
 657                         break;
 658                 default:
 659                         return -1;
 660                 }
 661                 if (l >= buf_size)
 662                         return 0;
 663                 buf[l] = 0;
 664                 origin = buf;
 665         } else {
 666                 origin = p->name;
 667         }
 668         t = strrchr(origin, '/');
 669         l = t ? t-origin : 0;
 670         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 671         if (!p->rpath) return -1;
 672
 673         d = p->rpath;
 674         s = p->rpath_orig;
 675         while ((t=strchr(s, '$'))) {
 676                 memcpy(d, s, t-s);
 677                 d += t-s;
 678                 memcpy(d, origin, l);
 679                 d += l;
 680                 /* It was determined previously that the '$' is followed
 681                  * either by "ORIGIN" or "{ORIGIN}". */
 682                 s = t + 7 + 2*(t[1]=='{');
 683         }
 684         strcpy(d, s);
 685         return 0;
 686 }
 687
 688 static void decode_dyn(struct dso *p)
 689 {
 690         size_t dyn[DYN_CNT];
 691         decode_vec(p->dynv, dyn, DYN_CNT);
 692         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 693         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 694         if (dyn[0]&(1<<DT_HASH))
 695                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 696         if (dyn[0]&(1<<DT_RPATH))
 697                 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
 698         if (dyn[0]&(1<<DT_RUNPATH))
 699                 p->rpath_orig = (void *)(p->strings + dyn[DT_RUNPATH]);
 700         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 701                 p->ghashtab = (void *)(p->base + *dyn);
 702         if (search_vec(p->dynv, dyn, DT_VERSYM))
 703                 p->versym = (void *)(p->base + *dyn);
 704 }
 705
 706 static struct dso *load_library(const char *name, struct dso *needed_by)
 707 {
 708         char buf[2*NAME_MAX+2];
 709         const char *pathname;
 710         unsigned char *map;
 711         struct dso *p, temp_dso = {0};
 712         int fd;
 713         struct stat st;
 714         size_t alloc_size;
 715         int n_th = 0;
 716         int is_self = 0;
 717
 718         if (!*name) {
 719                 errno = EINVAL;
 720                 return 0;
 721         }
 722
 723         /* Catch and block attempts to reload the implementation itself */
 724         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 725                 static const char *rp, reserved[] =
 726                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 727                 char *z = strchr(name, '.');
 728                 if (z) {
 729                         size_t l = z-name;
 730                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 731                         if (*rp) {
 732                                 if (ldd_mode) {
 733                                         /* Track which names have been resolved
 734                                          * and only report each one once. */
 735                                         static unsigned reported;
 736                                         unsigned mask = 1U<<(rp-reserved);
 737                                         if (!(reported & mask)) {
 738                                                 reported |= mask;
 739                                                 dprintf(1, "\t%s => %s (%p)\n",
 740                                                         name, ldso.name,
 741                                                         ldso.base);
 742                                         }
 743                                 }
 744                                 is_self = 1;
 745                         }
 746                 }
 747         }
 748         if (!strcmp(name, ldso.name)) is_self = 1;
 749         if (is_self) {
 750                 if (!ldso.prev) {
 751                         tail->next = &ldso;
 752                         ldso.prev = tail;
 753                         tail = ldso.next ? ldso.next : &ldso;
 754                 }
 755                 return &ldso;
 756         }
 757         if (strchr(name, '/')) {
 758                 pathname = name;
 759                 fd = open(name, O_RDONLY|O_CLOEXEC);
 760         } else {
 761                 /* Search for the name to see if it's already loaded */
 762                 for (p=head->next; p; p=p->next) {
 763                         if (p->shortname && !strcmp(p->shortname, name)) {
 764                                 p->refcnt++;
 765                                 return p;
 766                         }
 767                 }
 768                 if (strlen(name) > NAME_MAX) return 0;
 769                 fd = -1;
 770                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 771                 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
 772                         if (fixup_rpath(p, buf, sizeof buf) < 0)
 773                                 fd = -2; /* Inhibit further search. */
 774                         if (p->rpath)
 775                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 776                 }
 777                 if (fd == -1) {
 778                         if (!sys_path) {
 779                                 char *prefix = 0;
 780                                 size_t prefix_len;
 781                                 if (ldso.name[0]=='/') {
 782                                         char *s, *t, *z;
 783                                         for (s=t=z=ldso.name; *s; s++)
 784                                                 if (*s=='/') z=t, t=s;
 785                                         prefix_len = z-ldso.name;
 786                                         if (prefix_len < PATH_MAX)
 787                                                 prefix = ldso.name;
 788                                 }
 789                                 if (!prefix) {
 790                                         prefix = "";
 791                                         prefix_len = 0;
 792                                 }
 793                                 char etc_ldso_path[prefix_len + 1
 794                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 795                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 796                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 797                                         (int)prefix_len, prefix);
 798                                 FILE *f = fopen(etc_ldso_path, "rbe");
 799                                 if (f) {
 800                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 801                                                 free(sys_path);
 802                                                 sys_path = "";
 803                                         }
 804                                         fclose(f);
 805                                 } else if (errno != ENOENT) {
 806                                         sys_path = "";
 807                                 }
 808                         }
 809                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 810                         fd = path_open(name, sys_path, buf, sizeof buf);
 811                 }
 812                 pathname = buf;
 813         }
 814         if (fd < 0) return 0;
 815         if (fstat(fd, &st) < 0) {
 816                 close(fd);
 817                 return 0;
 818         }
 819         for (p=head->next; p; p=p->next) {
 820                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 821                         /* If this library was previously loaded with a
 822                          * pathname but a search found the same inode,
 823                          * setup its shortname so it can be found by name. */
 824                         if (!p->shortname && pathname != name)
 825                                 p->shortname = strrchr(p->name, '/')+1;
 826                         close(fd);
 827                         p->refcnt++;
 828                         return p;
 829                 }
 830         }
 831         map = noload ? 0 : map_library(fd, &temp_dso);
 832         close(fd);
 833         if (!map) return 0;
 834
 835         /* Allocate storage for the new DSO. When there is TLS, this
 836          * storage must include a reservation for all pre-existing
 837          * threads to obtain copies of both the new TLS, and an
 838          * extended DTV capable of storing an additional slot for
 839          * the newly-loaded DSO. */
 840         alloc_size = sizeof *p + strlen(pathname) + 1;
 841         if (runtime && temp_dso.tls_image) {
 842                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 843                         + sizeof(void *) * (tls_cnt+3);
 844                 n_th = libc.threads_minus_1 + 1;
 845                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 846                 else alloc_size += n_th * per_th;
 847         }
 848         p = calloc(1, alloc_size);
 849         if (!p) {
 850                 munmap(map, temp_dso.map_len);
 851                 return 0;
 852         }
 853         memcpy(p, &temp_dso, sizeof temp_dso);
 854         decode_dyn(p);
 855         p->dev = st.st_dev;
 856         p->ino = st.st_ino;
 857         p->refcnt = 1;
 858         p->needed_by = needed_by;
 859         p->name = p->buf;
 860         strcpy(p->name, pathname);
 861         /* Add a shortname only if name arg was not an explicit pathname. */
 862         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 863         if (p->tls_image) {
 864                 p->tls_id = ++tls_cnt;
 865                 tls_align = MAXP2(tls_align, p->tls_align);
 866 #ifdef TLS_ABOVE_TP
 867                 p->tls_offset = tls_offset + ( (tls_align-1) &
 868                         -(tls_offset + (uintptr_t)p->tls_image) );
 869                 tls_offset += p->tls_size;
 870 #else
 871                 tls_offset += p->tls_size + p->tls_align - 1;
 872                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 873                         & (p->tls_align-1);
 874                 p->tls_offset = tls_offset;
 875 #endif
 876                 p->new_dtv = (void *)(-sizeof(size_t) &
 877                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 878                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 879         }
 880
 881         tail->next = p;
 882         p->prev = tail;
 883         tail = p;
 884
 885         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 886
 887         return p;
 888 }
 889
 890 static void load_deps(struct dso *p)
 891 {
 892         size_t i, ndeps=0;
 893         struct dso ***deps = &p->deps, **tmp, *dep;
 894         for (; p; p=p->next) {
 895                 for (i=0; p->dynv[i]; i+=2) {
 896                         if (p->dynv[i] != DT_NEEDED) continue;
 897                         dep = load_library(p->strings + p->dynv[i+1], p);
 898                         if (!dep) {
 899                                 error("Error loading shared library %s: %m (needed by %s)",
 900                                         p->strings + p->dynv[i+1], p->name);
 901                                 if (runtime) longjmp(*rtld_fail, 1);
 902                                 continue;
 903                         }
 904                         if (runtime) {
 905                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 906                                 if (!tmp) longjmp(*rtld_fail, 1);
 907                                 tmp[ndeps++] = dep;
 908                                 tmp[ndeps] = 0;
 909                                 *deps = tmp;
 910                         }
 911                 }
 912         }
 913 }
 914
 915 static void load_preload(char *s)
 916 {
 917         int tmp;
 918         char *z;
 919         for (z=s; *z; s=z) {
 920                 for (   ; *s && (isspace(*s) || *s==':'); s++);
 921                 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
 922                 tmp = *z;
 923                 *z = 0;
 924                 load_library(s, 0);
 925                 *z = tmp;
 926         }
 927 }
 928
 929 static void make_global(struct dso *p)
 930 {
 931         for (; p; p=p->next) p->global = 1;
 932 }
 933
 934 static void do_mips_relocs(struct dso *p, size_t *got)
 935 {
 936         size_t i, j, rel[2];
 937         unsigned char *base = p->base;
 938         i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
 939         if (p==&ldso) {
 940                 got += i;
 941         } else {
 942                 while (i--) *got++ += (size_t)base;
 943         }
 944         j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
 945         i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
 946         Sym *sym = p->syms + j;
 947         rel[0] = (unsigned char *)got - base;
 948         for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
 949                 rel[1] = sym-p->syms << 8 | R_MIPS_JUMP_SLOT;
 950                 do_relocs(p, rel, sizeof rel, 2);
 951         }
 952 }
 953
 954 static void reloc_all(struct dso *p)
 955 {
 956         size_t dyn[DYN_CNT];
 957         for (; p; p=p->next) {
 958                 if (p->relocated) continue;
 959                 decode_vec(p->dynv, dyn, DYN_CNT);
 960                 if (NEED_MIPS_GOT_RELOCS)
 961                         do_mips_relocs(p, (void *)(p->base+dyn[DT_PLTGOT]));
 962                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 963                         2+(dyn[DT_PLTREL]==DT_RELA));
 964                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 965                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 966
 967                 if (head != &ldso && p->relro_start != p->relro_end &&
 968                     mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ)
 969                     && errno != ENOSYS) {
 970                         error("Error relocating %s: RELRO protection failed: %m",
 971                                 p->name);
 972                         if (runtime) longjmp(*rtld_fail, 1);
 973                 }
 974
 975                 p->relocated = 1;
 976         }
 977 }
 978
 979 static void kernel_mapped_dso(struct dso *p)
 980 {
 981         size_t min_addr = -1, max_addr = 0, cnt;
 982         Phdr *ph = p->phdr;
 983         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
 984                 if (ph->p_type == PT_DYNAMIC) {
 985                         p->dynv = (void *)(p->base + ph->p_vaddr);
 986                 } else if (ph->p_type == PT_GNU_RELRO) {
 987                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
 988                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 989                 }
 990                 if (ph->p_type != PT_LOAD) continue;
 991                 if (ph->p_vaddr < min_addr)
 992                         min_addr = ph->p_vaddr;
 993                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 994                         max_addr = ph->p_vaddr+ph->p_memsz;
 995         }
 996         min_addr &= -PAGE_SIZE;
 997         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 998         p->map = p->base + min_addr;
 999         p->map_len = max_addr - min_addr;
1000         p->kernel_mapped = 1;
1001 }
1002
1003 static void do_fini()
1004 {
1005         struct dso *p;
1006         size_t dyn[DYN_CNT];
1007         for (p=fini_head; p; p=p->fini_next) {
1008                 if (!p->constructed) continue;
1009                 decode_vec(p->dynv, dyn, DYN_CNT);
1010                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1011                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1012                         size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
1013                         while (n--) ((void (*)(void))*--fn)();
1014                 }
1015 #ifndef NO_LEGACY_INITFINI
1016                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1017                         ((void (*)(void))(p->base + dyn[DT_FINI]))();
1018 #endif
1019         }
1020 }
1021
1022 static void do_init_fini(struct dso *p)
1023 {
1024         size_t dyn[DYN_CNT];
1025         int need_locking = libc.threads_minus_1;
1026         /* Allow recursive calls that arise when a library calls
1027          * dlopen from one of its constructors, but block any
1028          * other threads until all ctors have finished. */
1029         if (need_locking) pthread_mutex_lock(&init_fini_lock);
1030         for (; p; p=p->prev) {
1031                 if (p->constructed) continue;
1032                 p->constructed = 1;
1033                 decode_vec(p->dynv, dyn, DYN_CNT);
1034                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1035                         p->fini_next = fini_head;
1036                         fini_head = p;
1037                 }
1038 #ifndef NO_LEGACY_INITFINI
1039                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1040                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
1041 #endif
1042                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1043                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1044                         size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
1045                         while (n--) ((void (*)(void))*fn++)();
1046                 }
1047                 if (!need_locking && libc.threads_minus_1) {
1048                         need_locking = 1;
1049                         pthread_mutex_lock(&init_fini_lock);
1050                 }
1051         }
1052         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1053 }
1054
1055 static void dl_debug_state(void)
1056 {
1057 }
1058
1059 weak_alias(dl_debug_state, _dl_debug_state);
1060
1061 void __reset_tls()
1062 {
1063         pthread_t self = __pthread_self();
1064         struct dso *p;
1065         for (p=head; p; p=p->next) {
1066                 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
1067                 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
1068                 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
1069                         p->tls_size - p->tls_len);
1070                 if (p->tls_id == (size_t)self->dtv[0]) break;
1071         }
1072 }
1073
1074 void *__copy_tls(unsigned char *mem)
1075 {
1076         pthread_t td;
1077         struct dso *p;
1078         void **dtv;
1079
1080 #ifdef TLS_ABOVE_TP
1081         dtv = (void **)(mem + libc.tls_size) - (tls_cnt + 1);
1082
1083         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
1084         td = (pthread_t)mem;
1085         mem += sizeof(struct pthread);
1086
1087         for (p=head; p; p=p->next) {
1088                 if (!p->tls_id) continue;
1089                 dtv[p->tls_id] = mem + p->tls_offset;
1090                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1091         }
1092 #else
1093         dtv = (void **)mem;
1094
1095         mem += libc.tls_size - sizeof(struct pthread);
1096         mem -= (uintptr_t)mem & (tls_align-1);
1097         td = (pthread_t)mem;
1098
1099         for (p=head; p; p=p->next) {
1100                 if (!p->tls_id) continue;
1101                 dtv[p->tls_id] = mem - p->tls_offset;
1102                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1103         }
1104 #endif
1105         dtv[0] = (void *)tls_cnt;
1106         td->dtv = td->dtv_copy = dtv;
1107         return td;
1108 }
1109
1110 __attribute__((__visibility__("hidden")))
1111 void *__tls_get_new(size_t *v)
1112 {
1113         pthread_t self = __pthread_self();
1114
1115         /* Block signals to make accessing new TLS async-signal-safe */
1116         sigset_t set;
1117         __block_all_sigs(&set);
1118         if (v[0]<=(size_t)self->dtv[0]) {
1119                 __restore_sigs(&set);
1120                 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1121         }
1122
1123         /* This is safe without any locks held because, if the caller
1124          * is able to request the Nth entry of the DTV, the DSO list
1125          * must be valid at least that far out and it was synchronized
1126          * at program startup or by an already-completed call to dlopen. */
1127         struct dso *p;
1128         for (p=head; p->tls_id != v[0]; p=p->next);
1129
1130         /* Get new DTV space from new DSO if needed */
1131         if (v[0] > (size_t)self->dtv[0]) {
1132                 void **newdtv = p->new_dtv +
1133                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1134                 memcpy(newdtv, self->dtv,
1135                         ((size_t)self->dtv[0]+1) * sizeof(void *));
1136                 newdtv[0] = (void *)v[0];
1137                 self->dtv = self->dtv_copy = newdtv;
1138         }
1139
1140         /* Get new TLS memory from all new DSOs up to the requested one */
1141         unsigned char *mem;
1142         for (p=head; ; p=p->next) {
1143                 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1144                 mem = p->new_tls + (p->tls_size + p->tls_align)
1145                         * a_fetch_add(&p->new_tls_idx,1);
1146                 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
1147                         & (p->tls_align-1);
1148                 self->dtv[p->tls_id] = mem;
1149                 memcpy(mem, p->tls_image, p->tls_len);
1150                 if (p->tls_id == v[0]) break;
1151         }
1152         __restore_sigs(&set);
1153         return mem + v[1] + DTP_OFFSET;
1154 }
1155
1156 static void update_tls_size()
1157 {
1158         libc.tls_size = ALIGN(
1159                 (1+tls_cnt) * sizeof(void *) +
1160                 tls_offset +
1161                 sizeof(struct pthread) +
1162                 tls_align * 2,
1163         tls_align);
1164 }
1165
1166 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1167  * following stage 2 and stage 3 functions via primitive symbolic lookup
1168  * since it does not have access to their addresses to begin with. */
1169
1170 /* Stage 2 of the dynamic linker is called after relative relocations
1171  * have been processed. It can make function calls to static functions
1172  * and access string literals and static data, but cannot use extern
1173  * symbols. Its job is to perform symbolic relocations on the dynamic
1174  * linker itself, but some of the relocations performed may need to be
1175  * replaced later due to copy relocations in the main program. */
1176
1177 void __dls2(unsigned char *base, size_t *sp)
1178 {
1179         Ehdr *ehdr = (void *)base;
1180         ldso.base = base;
1181         ldso.name = ldso.shortname = "libc.so";
1182         ldso.global = 1;
1183         ldso.phnum = ehdr->e_phnum;
1184         ldso.phdr = (void *)(base + ehdr->e_phoff);
1185         ldso.phentsize = ehdr->e_phentsize;
1186         kernel_mapped_dso(&ldso);
1187         decode_dyn(&ldso);
1188
1189         /* Prepare storage for to save clobbered REL addends so they
1190          * can be reused in stage 3. There should be very few. If
1191          * something goes wrong and there are a huge number, abort
1192          * instead of risking stack overflow. */
1193         size_t dyn[DYN_CNT];
1194         decode_vec(ldso.dynv, dyn, DYN_CNT);
1195         size_t *rel = (void *)(base+dyn[DT_REL]);
1196         size_t rel_size = dyn[DT_RELSZ];
1197         size_t symbolic_rel_cnt = 0;
1198         apply_addends_to = rel;
1199         for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1200                 if (!IS_RELATIVE(rel[1])) symbolic_rel_cnt++;
1201         if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1202         size_t addends[symbolic_rel_cnt+1];
1203         saved_addends = addends;
1204
1205         head = &ldso;
1206         reloc_all(&ldso);
1207
1208         ldso.relocated = 0;
1209
1210         /* Call dynamic linker stage-3, __dls3, looking it up
1211          * symbolically as a barrier against moving the address
1212          * load across the above relocation processing. */
1213         struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1214         ((stage3_func)(ldso.base+dls3_def.sym->st_value))(sp);
1215 }
1216
1217 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1218  * fully functional. Its job is to load (if not already loaded) and
1219  * process dependencies and relocations for the main application and
1220  * transfer control to its entry point. */
1221
1222 _Noreturn void __dls3(size_t *sp)
1223 {
1224         static struct dso app, vdso;
1225         size_t aux[AUX_CNT], *auxv;
1226         size_t i;
1227         char *env_preload=0;
1228         size_t vdso_base;
1229         int argc = *sp;
1230         char **argv = (void *)(sp+1);
1231         char **argv_orig = argv;
1232         char **envp = argv+argc+1;
1233
1234         /* Find aux vector just past environ[] and use it to initialize
1235          * global data that may be needed before we can make syscalls. */
1236         __environ = envp;
1237         for (i=argc+1; argv[i]; i++);
1238         libc.auxv = auxv = (void *)(argv+i+1);
1239         decode_vec(auxv, aux, AUX_CNT);
1240         __hwcap = aux[AT_HWCAP];
1241         libc.page_size = aux[AT_PAGESZ];
1242         libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1243                 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1244
1245         /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1246          * use during dynamic linking. If possible it will also serve as the
1247          * thread pointer at runtime. */
1248         libc.tls_size = sizeof builtin_tls;
1249         if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1250                 a_crash();
1251         }
1252
1253         /* Only trust user/env if kernel says we're not suid/sgid */
1254         if (!libc.secure) {
1255                 env_path = getenv("LD_LIBRARY_PATH");
1256                 env_preload = getenv("LD_PRELOAD");
1257         }
1258
1259         /* If the main program was already loaded by the kernel,
1260          * AT_PHDR will point to some location other than the dynamic
1261          * linker's program headers. */
1262         if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1263                 size_t interp_off = 0;
1264                 size_t tls_image = 0;
1265                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1266                 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1267                 app.phnum = aux[AT_PHNUM];
1268                 app.phentsize = aux[AT_PHENT];
1269                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1270                         if (phdr->p_type == PT_PHDR)
1271                                 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1272                         else if (phdr->p_type == PT_INTERP)
1273                                 interp_off = (size_t)phdr->p_vaddr;
1274                         else if (phdr->p_type == PT_TLS) {
1275                                 tls_image = phdr->p_vaddr;
1276                                 app.tls_len = phdr->p_filesz;
1277                                 app.tls_size = phdr->p_memsz;
1278                                 app.tls_align = phdr->p_align;
1279                         }
1280                 }
1281                 if (app.tls_size) app.tls_image = (char *)app.base + tls_image;
1282                 if (interp_off) ldso.name = (char *)app.base + interp_off;
1283                 if ((aux[0] & (1UL<<AT_EXECFN))
1284                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1285                         app.name = (char *)aux[AT_EXECFN];
1286                 else
1287                         app.name = argv[0];
1288                 kernel_mapped_dso(&app);
1289         } else {
1290                 int fd;
1291                 char *ldname = argv[0];
1292                 size_t l = strlen(ldname);
1293                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1294                 argv++;
1295                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1296                         char *opt = argv[0]+2;
1297                         *argv++ = (void *)-1;
1298                         if (!*opt) {
1299                                 break;
1300                         } else if (!memcmp(opt, "list", 5)) {
1301                                 ldd_mode = 1;
1302                         } else if (!memcmp(opt, "library-path", 12)) {
1303                                 if (opt[12]=='=') env_path = opt+13;
1304                                 else if (opt[12]) *argv = 0;
1305                                 else if (*argv) env_path = *argv++;
1306                         } else if (!memcmp(opt, "preload", 7)) {
1307                                 if (opt[7]=='=') env_preload = opt+8;
1308                                 else if (opt[7]) *argv = 0;
1309                                 else if (*argv) env_preload = *argv++;
1310                         } else {
1311                                 argv[0] = 0;
1312                         }
1313                 }
1314                 argv[-1] = (void *)(argc - (argv-argv_orig));
1315                 if (!argv[0]) {
1316                         dprintf(2, "musl libc\n"
1317                                 "Version %s\n"
1318                                 "Dynamic Program Loader\n"
1319                                 "Usage: %s [options] [--] pathname%s\n",
1320                                 __libc_get_version(), ldname,
1321                                 ldd_mode ? "" : " [args]");
1322                         _exit(1);
1323                 }
1324                 fd = open(argv[0], O_RDONLY);
1325                 if (fd < 0) {
1326                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1327                         _exit(1);
1328                 }
1329                 runtime = 1;
1330                 Ehdr *ehdr = (void *)map_library(fd, &app);
1331                 if (!ehdr) {
1332                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1333                         _exit(1);
1334                 }
1335                 runtime = 0;
1336                 close(fd);
1337                 ldso.name = ldname;
1338                 app.name = argv[0];
1339                 aux[AT_ENTRY] = (size_t)app.base + ehdr->e_entry;
1340                 /* Find the name that would have been used for the dynamic
1341                  * linker had ldd not taken its place. */
1342                 if (ldd_mode) {
1343                         for (i=0; i<app.phnum; i++) {
1344                                 if (app.phdr[i].p_type == PT_INTERP)
1345                                         ldso.name = (void *)(app.base
1346                                                 + app.phdr[i].p_vaddr);
1347                         }
1348                         dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1349                 }
1350         }
1351         if (app.tls_size) {
1352                 app.tls_id = tls_cnt = 1;
1353 #ifdef TLS_ABOVE_TP
1354                 app.tls_offset = 0;
1355                 tls_offset = app.tls_size
1356                         + ( -((uintptr_t)app.tls_image + app.tls_size)
1357                         & (app.tls_align-1) );
1358 #else
1359                 tls_offset = app.tls_offset = app.tls_size
1360                         + ( -((uintptr_t)app.tls_image + app.tls_size)
1361                         & (app.tls_align-1) );
1362 #endif
1363                 tls_align = MAXP2(tls_align, app.tls_align);
1364         }
1365         app.global = 1;
1366         decode_dyn(&app);
1367
1368         /* Attach to vdso, if provided by the kernel */
1369         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1370                 Ehdr *ehdr = (void *)vdso_base;
1371                 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1372                 vdso.phnum = ehdr->e_phnum;
1373                 vdso.phentsize = ehdr->e_phentsize;
1374                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1375                         if (phdr->p_type == PT_DYNAMIC)
1376                                 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1377                         if (phdr->p_type == PT_LOAD)
1378                                 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1379                 }
1380                 vdso.name = "";
1381                 vdso.shortname = "linux-gate.so.1";
1382                 vdso.global = 1;
1383                 vdso.relocated = 1;
1384                 decode_dyn(&vdso);
1385                 vdso.prev = &ldso;
1386                 ldso.next = &vdso;
1387         }
1388
1389         /* Initial dso chain consists only of the app. */
1390         head = tail = &app;
1391
1392         /* Donate unused parts of app and library mapping to malloc */
1393         reclaim_gaps(&app);
1394         reclaim_gaps(&ldso);
1395
1396         /* Load preload/needed libraries, add their symbols to the global
1397          * namespace, and perform all remaining relocations. */
1398         if (env_preload) load_preload(env_preload);
1399         load_deps(&app);
1400         make_global(&app);
1401
1402 #ifndef DYNAMIC_IS_RO
1403         for (i=0; app.dynv[i]; i+=2)
1404                 if (app.dynv[i]==DT_DEBUG)
1405                         app.dynv[i+1] = (size_t)&debug;
1406 #endif
1407
1408         /* The main program must be relocated LAST since it may contin
1409          * copy relocations which depend on libraries' relocations. */
1410         reloc_all(app.next);
1411         reloc_all(&app);
1412
1413         update_tls_size();
1414         if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1415                 void *initial_tls = calloc(libc.tls_size, 1);
1416                 if (!initial_tls) {
1417                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1418                                 argv[0], libc.tls_size);
1419                         _exit(127);
1420                 }
1421                 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1422                         a_crash();
1423                 }
1424         } else {
1425                 size_t tmp_tls_size = libc.tls_size;
1426                 pthread_t self = __pthread_self();
1427                 /* Temporarily set the tls size to the full size of
1428                  * builtin_tls so that __copy_tls will use the same layout
1429                  * as it did for before. Then check, just to be safe. */
1430                 libc.tls_size = sizeof builtin_tls;
1431                 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1432                 libc.tls_size = tmp_tls_size;
1433         }
1434         static_tls_cnt = tls_cnt;
1435
1436         if (ldso_fail) _exit(127);
1437         if (ldd_mode) _exit(0);
1438
1439         /* Switch to runtime mode: any further failures in the dynamic
1440          * linker are a reportable failure rather than a fatal startup
1441          * error. */
1442         runtime = 1;
1443
1444         debug.ver = 1;
1445         debug.bp = dl_debug_state;
1446         debug.head = head;
1447         debug.base = ldso.base;
1448         debug.state = 0;
1449         _dl_debug_state();
1450
1451         __init_libc(envp, argv[0]);
1452         atexit(do_fini);
1453         errno = 0;
1454         do_init_fini(tail);
1455
1456         CRTJMP((void *)aux[AT_ENTRY], argv-1);
1457         for(;;);
1458 }
1459
1460 void *dlopen(const char *file, int mode)
1461 {
1462         struct dso *volatile p, *orig_tail, *next;
1463         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1464         size_t i;
1465         int cs;
1466         jmp_buf jb;
1467
1468         if (!file) return head;
1469
1470         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1471         pthread_rwlock_wrlock(&lock);
1472         __inhibit_ptc();
1473
1474         p = 0;
1475         orig_tls_cnt = tls_cnt;
1476         orig_tls_offset = tls_offset;
1477         orig_tls_align = tls_align;
1478         orig_tail = tail;
1479         noload = mode & RTLD_NOLOAD;
1480
1481         rtld_fail = &jb;
1482         if (setjmp(*rtld_fail)) {
1483                 /* Clean up anything new that was (partially) loaded */
1484                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1485                         if (p->deps[i]->global < 0)
1486                                 p->deps[i]->global = 0;
1487                 for (p=orig_tail->next; p; p=next) {
1488                         next = p->next;
1489                         munmap(p->map, p->map_len);
1490                         while (p->td_index) {
1491                                 void *tmp = p->td_index->next;
1492                                 free(p->td_index);
1493                                 p->td_index = tmp;
1494                         }
1495                         if (p->rpath != p->rpath_orig)
1496                                 free(p->rpath);
1497                         free(p->deps);
1498                         free(p);
1499                 }
1500                 tls_cnt = orig_tls_cnt;
1501                 tls_offset = orig_tls_offset;
1502                 tls_align = orig_tls_align;
1503                 tail = orig_tail;
1504                 tail->next = 0;
1505                 p = 0;
1506                 goto end;
1507         } else p = load_library(file, head);
1508
1509         if (!p) {
1510                 error(noload ?
1511                         "Library %s is not already loaded" :
1512                         "Error loading shared library %s: %m",
1513                         file);
1514                 goto end;
1515         }
1516
1517         /* First load handling */
1518         if (!p->deps) {
1519                 load_deps(p);
1520                 if (p->deps) for (i=0; p->deps[i]; i++)
1521                         if (!p->deps[i]->global)
1522                                 p->deps[i]->global = -1;
1523                 if (!p->global) p->global = -1;
1524                 reloc_all(p);
1525                 if (p->deps) for (i=0; p->deps[i]; i++)
1526                         if (p->deps[i]->global < 0)
1527                                 p->deps[i]->global = 0;
1528                 if (p->global < 0) p->global = 0;
1529         }
1530
1531         if (mode & RTLD_GLOBAL) {
1532                 if (p->deps) for (i=0; p->deps[i]; i++)
1533                         p->deps[i]->global = 1;
1534                 p->global = 1;
1535         }
1536
1537         update_tls_size();
1538         _dl_debug_state();
1539         orig_tail = tail;
1540 end:
1541         __release_ptc();
1542         if (p) gencnt++;
1543         pthread_rwlock_unlock(&lock);
1544         if (p) do_init_fini(orig_tail);
1545         pthread_setcancelstate(cs, 0);
1546         return p;
1547 }
1548
1549 static int invalid_dso_handle(void *h)
1550 {
1551         struct dso *p;
1552         for (p=head; p; p=p->next) if (h==p) return 0;
1553         error("Invalid library handle %p", (void *)h);
1554         return 1;
1555 }
1556
1557 void *__tls_get_addr(size_t *);
1558
1559 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1560 {
1561         size_t i;
1562         uint32_t h = 0, gh = 0;
1563         Sym *sym;
1564         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1565                 if (p == RTLD_DEFAULT) {
1566                         p = head;
1567                 } else if (p == RTLD_NEXT) {
1568                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1569                         if (!p) p=head;
1570                         p = p->next;
1571                 }
1572                 struct symdef def = find_sym(p, s, 0);
1573                 if (!def.sym) goto failed;
1574                 if ((def.sym->st_info&0xf) == STT_TLS)
1575                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1576                 return def.dso->base + def.sym->st_value;
1577         }
1578         if (invalid_dso_handle(p))
1579                 return 0;
1580         if (p->ghashtab) {
1581                 gh = gnu_hash(s);
1582                 sym = gnu_lookup(s, gh, p);
1583         } else {
1584                 h = sysv_hash(s);
1585                 sym = sysv_lookup(s, h, p);
1586         }
1587         if (sym && (sym->st_info&0xf) == STT_TLS)
1588                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1589         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1590                 return p->base + sym->st_value;
1591         if (p->deps) for (i=0; p->deps[i]; i++) {
1592                 if (p->deps[i]->ghashtab) {
1593                         if (!gh) gh = gnu_hash(s);
1594                         sym = gnu_lookup(s, gh, p->deps[i]);
1595                 } else {
1596                         if (!h) h = sysv_hash(s);
1597                         sym = sysv_lookup(s, h, p->deps[i]);
1598                 }
1599                 if (sym && (sym->st_info&0xf) == STT_TLS)
1600                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1601                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1602                         return p->deps[i]->base + sym->st_value;
1603         }
1604 failed:
1605         error("Symbol not found: %s", s);
1606         return 0;
1607 }
1608
1609 int __dladdr(const void *addr, Dl_info *info)
1610 {
1611         struct dso *p;
1612         Sym *sym;
1613         uint32_t nsym;
1614         char *strings;
1615         size_t i;
1616         void *best = 0;
1617         char *bestname;
1618
1619         pthread_rwlock_rdlock(&lock);
1620         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1621         pthread_rwlock_unlock(&lock);
1622
1623         if (!p) return 0;
1624
1625         sym = p->syms;
1626         strings = p->strings;
1627         if (p->hashtab) {
1628                 nsym = p->hashtab[1];
1629         } else {
1630                 uint32_t *buckets;
1631                 uint32_t *hashval;
1632                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1633                 sym += p->ghashtab[1];
1634                 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1635                         if (buckets[i] > nsym)
1636                                 nsym = buckets[i];
1637                 }
1638                 if (nsym) {
1639                         nsym -= p->ghashtab[1];
1640                         hashval = buckets + p->ghashtab[0] + nsym;
1641                         do nsym++;
1642                         while (!(*hashval++ & 1));
1643                 }
1644         }
1645
1646         for (; nsym; nsym--, sym++) {
1647                 if (sym->st_value
1648                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1649                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1650                         void *symaddr = p->base + sym->st_value;
1651                         if (symaddr > addr || symaddr < best)
1652                                 continue;
1653                         best = symaddr;
1654                         bestname = strings + sym->st_name;
1655                         if (addr == symaddr)
1656                                 break;
1657                 }
1658         }
1659
1660         if (!best) return 0;
1661
1662         info->dli_fname = p->name;
1663         info->dli_fbase = p->base;
1664         info->dli_sname = bestname;
1665         info->dli_saddr = best;
1666
1667         return 1;
1668 }
1669
1670 __attribute__((__visibility__("hidden")))
1671 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1672 {
1673         void *res;
1674         pthread_rwlock_rdlock(&lock);
1675         res = do_dlsym(p, s, ra);
1676         pthread_rwlock_unlock(&lock);
1677         return res;
1678 }
1679
1680 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1681 {
1682         struct dso *current;
1683         struct dl_phdr_info info;
1684         int ret = 0;
1685         for(current = head; current;) {
1686                 info.dlpi_addr      = (uintptr_t)current->base;
1687                 info.dlpi_name      = current->name;
1688                 info.dlpi_phdr      = current->phdr;
1689                 info.dlpi_phnum     = current->phnum;
1690                 info.dlpi_adds      = gencnt;
1691                 info.dlpi_subs      = 0;
1692                 info.dlpi_tls_modid = current->tls_id;
1693                 info.dlpi_tls_data  = current->tls_image;
1694
1695                 ret = (callback)(&info, sizeof (info), data);
1696
1697                 if (ret != 0) break;
1698
1699                 pthread_rwlock_rdlock(&lock);
1700                 current = current->next;
1701                 pthread_rwlock_unlock(&lock);
1702         }
1703         return ret;
1704 }
1705 #else
1706 static int invalid_dso_handle(void *h)
1707 {
1708         error("Invalid library handle %p", (void *)h);
1709         return 1;
1710 }
1711 void *dlopen(const char *file, int mode)
1712 {
1713         error("Dynamic loading not supported");
1714         return 0;
1715 }
1716 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1717 {
1718         error("Symbol not found: %s", s);
1719         return 0;
1720 }
1721 int __dladdr (const void *addr, Dl_info *info)
1722 {
1723         return 0;
1724 }
1725 #endif
1726
1727 int __dlinfo(void *dso, int req, void *res)
1728 {
1729         if (invalid_dso_handle(dso)) return -1;
1730         if (req != RTLD_DI_LINKMAP) {
1731                 error("Unsupported request %d", req);
1732                 return -1;
1733         }
1734         *(struct link_map **)res = dso;
1735         return 0;
1736 }
1737
1738 char *dlerror()
1739 {
1740         pthread_t self = __pthread_self();
1741         if (!self->dlerror_flag) return 0;
1742         self->dlerror_flag = 0;
1743         char *s = self->dlerror_buf;
1744         if (s == (void *)-1)
1745                 return "Dynamic linker failed to allocate memory for error message";
1746         else
1747                 return s;
1748 }
1749
1750 int dlclose(void *p)
1751 {
1752         return invalid_dso_handle(p);
1753 }
1754
1755 void __dl_thread_cleanup(void)
1756 {
1757         pthread_t self = __pthread_self();
1758         if (self->dlerror_buf != (void *)-1)
1759                 free(self->dlerror_buf);
1760 }
1761
1762 static void error(const char *fmt, ...)
1763 {
1764         va_list ap;
1765         va_start(ap, fmt);
1766 #ifdef SHARED
1767         if (!runtime) {
1768                 vdprintf(2, fmt, ap);
1769                 dprintf(2, "\n");
1770                 ldso_fail = 1;
1771                 va_end(ap);
1772                 return;
1773         }
1774 #endif
1775         pthread_t self = __pthread_self();
1776         if (self->dlerror_buf != (void *)-1)
1777                 free(self->dlerror_buf);
1778         size_t len = vsnprintf(0, 0, fmt, ap);
1779         va_end(ap);
1780         char *buf = malloc(len+1);
1781         if (buf) {
1782                 va_start(ap, fmt);
1783                 vsnprintf(buf, len+1, fmt, ap);
1784                 va_end(ap);
1785         } else {
1786                 buf = (void *)-1;
1787         }
1788         self->dlerror_buf = buf;
1789         self->dlerror_flag = 1;
1790 }