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 #if DL_FDPIC
  46         struct fdpic_loadmap *loadmap;
  47 #else
  48         unsigned char *base;
  49 #endif
  50         char *name;
  51         size_t *dynv;
  52         struct dso *next, *prev;
  53
  54         Phdr *phdr;
  55         int phnum;
  56         size_t phentsize;
  57         int refcnt;
  58         Sym *syms;
  59         uint32_t *hashtab;
  60         uint32_t *ghashtab;
  61         int16_t *versym;
  62         char *strings;
  63         unsigned char *map;
  64         size_t map_len;
  65         dev_t dev;
  66         ino_t ino;
  67         signed char global;
  68         char relocated;
  69         char constructed;
  70         char kernel_mapped;
  71         struct dso **deps, *needed_by;
  72         char *rpath_orig, *rpath;
  73         void *tls_image;
  74         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  75         size_t relro_start, relro_end;
  76         void **new_dtv;
  77         unsigned char *new_tls;
  78         volatile int new_dtv_idx, new_tls_idx;
  79         struct td_index *td_index;
  80         struct dso *fini_next;
  81         char *shortname;
  82 #if DL_FDPIC
  83         unsigned char *base;
  84 #else
  85         struct fdpic_loadmap *loadmap;
  86 #endif
  87         struct funcdesc {
  88                 void *addr;
  89                 size_t *got;
  90         } *funcdescs;
  91         size_t *got;
  92         char buf[];
  93 };
  94
  95 struct symdef {
  96         Sym *sym;
  97         struct dso *dso;
  98 };
  99
 100 int __init_tp(void *);
 101 void __init_libc(char **, char *);
 102
 103 const char *__libc_get_version(void);
 104
 105 static struct builtin_tls {
 106         char c;
 107         struct pthread pt;
 108         void *space[16];
 109 } builtin_tls[1];
 110 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
 111
 112 #define ADDEND_LIMIT 4096
 113 static size_t *saved_addends, *apply_addends_to;
 114
 115 static struct dso ldso;
 116 static struct dso *head, *tail, *fini_head;
 117 static char *env_path, *sys_path;
 118 static unsigned long long gencnt;
 119 static int runtime;
 120 static int ldd_mode;
 121 static int ldso_fail;
 122 static int noload;
 123 static jmp_buf *rtld_fail;
 124 static pthread_rwlock_t lock;
 125 static struct debug debug;
 126 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
 127 static size_t static_tls_cnt;
 128 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 129 static struct fdpic_loadmap *app_loadmap;
 130 static struct fdpic_dummy_loadmap app_dummy_loadmap;
 131
 132 struct debug *_dl_debug_addr = &debug;
 133
 134 static int dl_strcmp(const char *l, const char *r)
 135 {
 136         for (; *l==*r && *l; l++, r++);
 137         return *(unsigned char *)l - *(unsigned char *)r;
 138 }
 139 #define strcmp(l,r) dl_strcmp(l,r)
 140
 141 /* Compute load address for a virtual address in a given dso. */
 142 #ifdef DL_FDPIC
 143 static void *laddr(const struct dso *p, size_t v)
 144 {
 145         size_t j=0;
 146         if (!p->loadmap) return p->base + v;
 147         for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
 148         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 149 }
 150 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
 151         laddr(p, v), (p)->got })
 152 #else
 153 #define laddr(p, v) (void *)((p)->base + (v))
 154 #define fpaddr(p, v) ((void (*)())laddr(p, v))
 155 #endif
 156
 157 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 158 {
 159         size_t i;
 160         for (i=0; i<cnt; i++) a[i] = 0;
 161         for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
 162                 a[0] |= 1UL<<v[0];
 163                 a[v[0]] = v[1];
 164         }
 165 }
 166
 167 static int search_vec(size_t *v, size_t *r, size_t key)
 168 {
 169         for (; v[0]!=key; v+=2)
 170                 if (!v[0]) return 0;
 171         *r = v[1];
 172         return 1;
 173 }
 174
 175 static uint32_t sysv_hash(const char *s0)
 176 {
 177         const unsigned char *s = (void *)s0;
 178         uint_fast32_t h = 0;
 179         while (*s) {
 180                 h = 16*h + *s++;
 181                 h ^= h>>24 & 0xf0;
 182         }
 183         return h & 0xfffffff;
 184 }
 185
 186 static uint32_t gnu_hash(const char *s0)
 187 {
 188         const unsigned char *s = (void *)s0;
 189         uint_fast32_t h = 5381;
 190         for (; *s; s++)
 191                 h += h*32 + *s;
 192         return h;
 193 }
 194
 195 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 196 {
 197         size_t i;
 198         Sym *syms = dso->syms;
 199         uint32_t *hashtab = dso->hashtab;
 200         char *strings = dso->strings;
 201         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 202                 if ((!dso->versym || dso->versym[i] >= 0)
 203                     && (!strcmp(s, strings+syms[i].st_name)))
 204                         return syms+i;
 205         }
 206         return 0;
 207 }
 208
 209 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
 210 {
 211         uint32_t nbuckets = hashtab[0];
 212         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 213         uint32_t i = buckets[h1 % nbuckets];
 214
 215         if (!i) return 0;
 216
 217         uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
 218
 219         for (h1 |= 1; ; i++) {
 220                 uint32_t h2 = *hashval++;
 221                 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
 222                     && !strcmp(s, dso->strings + dso->syms[i].st_name))
 223                         return dso->syms+i;
 224                 if (h2 & 1) break;
 225         }
 226
 227         return 0;
 228 }
 229
 230 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
 231 {
 232         const size_t *bloomwords = (const void *)(hashtab+4);
 233         size_t f = bloomwords[fofs & (hashtab[2]-1)];
 234         if (!(f & fmask)) return 0;
 235
 236         f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
 237         if (!(f & 1)) return 0;
 238
 239         return gnu_lookup(h1, hashtab, dso, s);
 240 }
 241
 242 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 243 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 244
 245 #ifndef ARCH_SYM_REJECT_UND
 246 #define ARCH_SYM_REJECT_UND(s) 0
 247 #endif
 248
 249 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 250 {
 251         uint32_t h = 0, gh, gho, *ght;
 252         size_t ghm = 0;
 253         struct symdef def = {0};
 254         for (; dso; dso=dso->next) {
 255                 Sym *sym;
 256                 if (!dso->global) continue;
 257                 if ((ght = dso->ghashtab)) {
 258                         if (!ghm) {
 259                                 gh = gnu_hash(s);
 260                                 int maskbits = 8 * sizeof ghm;
 261                                 gho = gh / maskbits;
 262                                 ghm = 1ul << gh % maskbits;
 263                         }
 264                         sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
 265                 } else {
 266                         if (!h) h = sysv_hash(s);
 267                         sym = sysv_lookup(s, h, dso);
 268                 }
 269                 if (!sym) continue;
 270                 if (!sym->st_shndx)
 271                         if (need_def || (sym->st_info&0xf) == STT_TLS
 272                             || ARCH_SYM_REJECT_UND(sym))
 273                                 continue;
 274                 if (!sym->st_value)
 275                         if ((sym->st_info&0xf) != STT_TLS)
 276                                 continue;
 277                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 278                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 279
 280                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 281                 def.sym = sym;
 282                 def.dso = dso;
 283                 if (sym->st_info>>4 == STB_GLOBAL) break;
 284         }
 285         return def;
 286 }
 287
 288 __attribute__((__visibility__("hidden")))
 289 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
 290
 291 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 292 {
 293         unsigned char *base = dso->base;
 294         Sym *syms = dso->syms;
 295         char *strings = dso->strings;
 296         Sym *sym;
 297         const char *name;
 298         void *ctx;
 299         int type;
 300         int sym_index;
 301         struct symdef def;
 302         size_t *reloc_addr;
 303         size_t sym_val;
 304         size_t tls_val;
 305         size_t addend;
 306         int skip_relative = 0, reuse_addends = 0, save_slot = 0;
 307
 308         if (dso == &ldso) {
 309                 /* Only ldso's REL table needs addend saving/reuse. */
 310                 if (rel == apply_addends_to)
 311                         reuse_addends = 1;
 312                 skip_relative = 1;
 313         }
 314
 315         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 316                 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
 317                 type = R_TYPE(rel[1]);
 318                 if (type == REL_NONE) continue;
 319                 sym_index = R_SYM(rel[1]);
 320                 reloc_addr = laddr(dso, rel[0]);
 321                 if (sym_index) {
 322                         sym = syms + sym_index;
 323                         name = strings + sym->st_name;
 324                         ctx = type==REL_COPY ? head->next : head;
 325                         def = (sym->st_info&0xf) == STT_SECTION
 326                                 ? (struct symdef){ .dso = dso, .sym = sym }
 327                                 : find_sym(ctx, name, type==REL_PLT);
 328                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 329                             || sym->st_info>>4 != STB_WEAK)) {
 330                                 error("Error relocating %s: %s: symbol not found",
 331                                         dso->name, name);
 332                                 if (runtime) longjmp(*rtld_fail, 1);
 333                                 continue;
 334                         }
 335                 } else {
 336                         sym = 0;
 337                         def.sym = 0;
 338                         def.dso = dso;
 339                 }
 340
 341                 if (stride > 2) {
 342                         addend = rel[2];
 343                 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
 344                         addend = 0;
 345                 } else if (reuse_addends) {
 346                         /* Save original addend in stage 2 where the dso
 347                          * chain consists of just ldso; otherwise read back
 348                          * saved addend since the inline one was clobbered. */
 349                         if (head==&ldso)
 350                                 saved_addends[save_slot] = *reloc_addr;
 351                         addend = saved_addends[save_slot++];
 352                 } else {
 353                         addend = *reloc_addr;
 354                 }
 355
 356                 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
 357                 tls_val = def.sym ? def.sym->st_value : 0;
 358
 359                 switch(type) {
 360                 case REL_NONE:
 361                         break;
 362                 case REL_OFFSET:
 363                         addend -= (size_t)reloc_addr;
 364                 case REL_SYMBOLIC:
 365                 case REL_GOT:
 366                 case REL_PLT:
 367                         *reloc_addr = sym_val + addend;
 368                         break;
 369                 case REL_RELATIVE:
 370                         *reloc_addr = (size_t)base + addend;
 371                         break;
 372                 case REL_SYM_OR_REL:
 373                         if (sym) *reloc_addr = sym_val + addend;
 374                         else *reloc_addr = (size_t)base + addend;
 375                         break;
 376                 case REL_COPY:
 377                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 378                         break;
 379                 case REL_OFFSET32:
 380                         *(uint32_t *)reloc_addr = sym_val + addend
 381                                 - (size_t)reloc_addr;
 382                         break;
 383                 case REL_FUNCDESC:
 384                         *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
 385                                 + (def.sym - def.dso->syms)) : 0;
 386                         break;
 387                 case REL_FUNCDESC_VAL:
 388                         if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
 389                         else *reloc_addr = sym_val;
 390                         reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
 391                         break;
 392                 case REL_DTPMOD:
 393                         *reloc_addr = def.dso->tls_id;
 394                         break;
 395                 case REL_DTPOFF:
 396                         *reloc_addr = tls_val + addend - DTP_OFFSET;
 397                         break;
 398 #ifdef TLS_ABOVE_TP
 399                 case REL_TPOFF:
 400                         *reloc_addr = tls_val + def.dso->tls_offset + TPOFF_K + addend;
 401                         break;
 402 #else
 403                 case REL_TPOFF:
 404                         *reloc_addr = tls_val - def.dso->tls_offset + addend;
 405                         break;
 406                 case REL_TPOFF_NEG:
 407                         *reloc_addr = def.dso->tls_offset - tls_val + addend;
 408                         break;
 409 #endif
 410                 case REL_TLSDESC:
 411                         if (stride<3) addend = reloc_addr[1];
 412                         if (runtime && def.dso->tls_id >= static_tls_cnt) {
 413                                 struct td_index *new = malloc(sizeof *new);
 414                                 if (!new) {
 415                                         error(
 416                                         "Error relocating %s: cannot allocate TLSDESC for %s",
 417                                         dso->name, sym ? name : "(local)" );
 418                                         longjmp(*rtld_fail, 1);
 419                                 }
 420                                 new->next = dso->td_index;
 421                                 dso->td_index = new;
 422                                 new->args[0] = def.dso->tls_id;
 423                                 new->args[1] = tls_val + addend;
 424                                 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
 425                                 reloc_addr[1] = (size_t)new;
 426                         } else {
 427                                 reloc_addr[0] = (size_t)__tlsdesc_static;
 428 #ifdef TLS_ABOVE_TP
 429                                 reloc_addr[1] = tls_val + def.dso->tls_offset
 430                                         + TPOFF_K + addend;
 431 #else
 432                                 reloc_addr[1] = tls_val - def.dso->tls_offset
 433                                         + addend;
 434 #endif
 435                         }
 436                         break;
 437                 default:
 438                         error("Error relocating %s: unsupported relocation type %d",
 439                                 dso->name, type);
 440                         if (runtime) longjmp(*rtld_fail, 1);
 441                         continue;
 442                 }
 443         }
 444 }
 445
 446 /* A huge hack: to make up for the wastefulness of shared libraries
 447  * needing at least a page of dirty memory even if they have no global
 448  * data, we reclaim the gaps at the beginning and end of writable maps
 449  * and "donate" them to the heap by setting up minimal malloc
 450  * structures and then freeing them. */
 451
 452 static void reclaim(struct dso *dso, size_t start, size_t end)
 453 {
 454         size_t *a, *z;
 455         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 456         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 457         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 458         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 459         if (start>end || end-start < 4*sizeof(size_t)) return;
 460         a = laddr(dso, start);
 461         z = laddr(dso, end);
 462         a[-2] = 1;
 463         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 464         z[1] = 1;
 465         free(a);
 466 }
 467
 468 static void reclaim_gaps(struct dso *dso)
 469 {
 470         Phdr *ph = dso->phdr;
 471         size_t phcnt = dso->phnum;
 472
 473         if (DL_FDPIC) return; // FIXME
 474         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 475                 if (ph->p_type!=PT_LOAD) continue;
 476                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 477                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 478                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 479                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 480         }
 481 }
 482
 483 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
 484 {
 485         char *q = mmap(p, n, prot, flags, fd, off);
 486         if (q != MAP_FAILED || errno != EINVAL) return q;
 487         /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
 488         if (flags & MAP_ANONYMOUS) {
 489                 memset(p, 0, n);
 490                 return p;
 491         }
 492         ssize_t r;
 493         if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
 494         for (q=p; n; q+=r, off+=r, n-=r) {
 495                 r = read(fd, q, n);
 496                 if (r < 0 && errno != EINTR) return MAP_FAILED;
 497                 if (!r) {
 498                         memset(q, 0, n);
 499                         break;
 500                 }
 501         }
 502         return p;
 503 }
 504
 505 static void *map_library(int fd, struct dso *dso)
 506 {
 507         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 508         void *allocated_buf=0;
 509         size_t phsize;
 510         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 511         size_t this_min, this_max;
 512         off_t off_start;
 513         Ehdr *eh;
 514         Phdr *ph, *ph0;
 515         unsigned prot;
 516         unsigned char *map=MAP_FAILED, *base;
 517         size_t dyn=0;
 518         size_t tls_image=0;
 519         size_t i;
 520
 521         ssize_t l = read(fd, buf, sizeof buf);
 522         eh = buf;
 523         if (l<0) return 0;
 524         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 525                 goto noexec;
 526         phsize = eh->e_phentsize * eh->e_phnum;
 527         if (phsize > sizeof buf - sizeof *eh) {
 528                 allocated_buf = malloc(phsize);
 529                 if (!allocated_buf) return 0;
 530                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 531                 if (l < 0) goto error;
 532                 if (l != phsize) goto noexec;
 533                 ph = ph0 = allocated_buf;
 534         } else if (eh->e_phoff + phsize > l) {
 535                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 536                 if (l < 0) goto error;
 537                 if (l != phsize) goto noexec;
 538                 ph = ph0 = (void *)(buf + 1);
 539         } else {
 540                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 541         }
 542         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 543                 if (ph->p_type == PT_DYNAMIC) {
 544                         dyn = ph->p_vaddr;
 545                 } else if (ph->p_type == PT_TLS) {
 546                         tls_image = ph->p_vaddr;
 547                         dso->tls_align = ph->p_align;
 548                         dso->tls_len = ph->p_filesz;
 549                         dso->tls_size = ph->p_memsz;
 550                 } else if (ph->p_type == PT_GNU_RELRO) {
 551                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 552                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 553                 }
 554                 if (ph->p_type != PT_LOAD) continue;
 555                 if (ph->p_vaddr < addr_min) {
 556                         addr_min = ph->p_vaddr;
 557                         off_start = ph->p_offset;
 558                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 559                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 560                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 561                 }
 562                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 563                         addr_max = ph->p_vaddr+ph->p_memsz;
 564                 }
 565         }
 566         if (!dyn) goto noexec;
 567         addr_max += PAGE_SIZE-1;
 568         addr_max &= -PAGE_SIZE;
 569         addr_min &= -PAGE_SIZE;
 570         off_start &= -PAGE_SIZE;
 571         map_len = addr_max - addr_min + off_start;
 572         /* The first time, we map too much, possibly even more than
 573          * the length of the file. This is okay because we will not
 574          * use the invalid part; we just need to reserve the right
 575          * amount of virtual address space to map over later. */
 576         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 577         if (map==MAP_FAILED) goto error;
 578         /* If the loaded file is not relocatable and the requested address is
 579          * not available, then the load operation must fail. */
 580         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 581                 errno = EBUSY;
 582                 goto error;
 583         }
 584         base = map - addr_min;
 585         dso->phdr = 0;
 586         dso->phnum = 0;
 587         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 588                 if (ph->p_type != PT_LOAD) continue;
 589                 /* Check if the programs headers are in this load segment, and
 590                  * if so, record the address for use by dl_iterate_phdr. */
 591                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 592                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 593                         dso->phdr = (void *)(base + ph->p_vaddr
 594                                 + (eh->e_phoff-ph->p_offset));
 595                         dso->phnum = eh->e_phnum;
 596                         dso->phentsize = eh->e_phentsize;
 597                 }
 598                 /* Reuse the existing mapping for the lowest-address LOAD */
 599                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 600                 this_min = ph->p_vaddr & -PAGE_SIZE;
 601                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 602                 off_start = ph->p_offset & -PAGE_SIZE;
 603                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 604                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 605                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 606                 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 607                         goto error;
 608                 if (ph->p_memsz > ph->p_filesz) {
 609                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 610                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 611                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 612                         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)
 613                                 goto error;
 614                 }
 615         }
 616         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 617                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 618                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
 619                             && errno != ENOSYS)
 620                                 goto error;
 621                         break;
 622                 }
 623         dso->map = map;
 624         dso->map_len = map_len;
 625         dso->base = base;
 626         dso->dynv = (void *)(base+dyn);
 627         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 628         if (!runtime) reclaim_gaps(dso);
 629         free(allocated_buf);
 630         return map;
 631 noexec:
 632         errno = ENOEXEC;
 633 error:
 634         if (map!=MAP_FAILED) munmap(map, map_len);
 635         free(allocated_buf);
 636         return 0;
 637 }
 638
 639 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 640 {
 641         size_t l;
 642         int fd;
 643         for (;;) {
 644                 s += strspn(s, ":\n");
 645                 l = strcspn(s, ":\n");
 646                 if (l-1 >= INT_MAX) return -1;
 647                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
 648                         if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 649                         switch (errno) {
 650                         case ENOENT:
 651                         case ENOTDIR:
 652                         case EACCES:
 653                         case ENAMETOOLONG:
 654                                 break;
 655                         default:
 656                                 /* Any negative value but -1 will inhibit
 657                                  * futher path search. */
 658                                 return -2;
 659                         }
 660                 }
 661                 s += l;
 662         }
 663 }
 664
 665 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 666 {
 667         size_t n, l;
 668         const char *s, *t, *origin;
 669         char *d;
 670         if (p->rpath || !p->rpath_orig) return 0;
 671         if (!strchr(p->rpath_orig, '$')) {
 672                 p->rpath = p->rpath_orig;
 673                 return 0;
 674         }
 675         n = 0;
 676         s = p->rpath_orig;
 677         while ((t=strchr(s, '$'))) {
 678                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 679                         return 0;
 680                 s = t+1;
 681                 n++;
 682         }
 683         if (n > SSIZE_MAX/PATH_MAX) return 0;
 684
 685         if (p->kernel_mapped) {
 686                 /* $ORIGIN searches cannot be performed for the main program
 687                  * when it is suid/sgid/AT_SECURE. This is because the
 688                  * pathname is under the control of the caller of execve.
 689                  * For libraries, however, $ORIGIN can be processed safely
 690                  * since the library's pathname came from a trusted source
 691                  * (either system paths or a call to dlopen). */
 692                 if (libc.secure)
 693                         return 0;
 694                 l = readlink("/proc/self/exe", buf, buf_size);
 695                 if (l == -1) switch (errno) {
 696                 case ENOENT:
 697                 case ENOTDIR:
 698                 case EACCES:
 699                         break;
 700                 default:
 701                         return -1;
 702                 }
 703                 if (l >= buf_size)
 704                         return 0;
 705                 buf[l] = 0;
 706                 origin = buf;
 707         } else {
 708                 origin = p->name;
 709         }
 710         t = strrchr(origin, '/');
 711         l = t ? t-origin : 0;
 712         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 713         if (!p->rpath) return -1;
 714
 715         d = p->rpath;
 716         s = p->rpath_orig;
 717         while ((t=strchr(s, '$'))) {
 718                 memcpy(d, s, t-s);
 719                 d += t-s;
 720                 memcpy(d, origin, l);
 721                 d += l;
 722                 /* It was determined previously that the '$' is followed
 723                  * either by "ORIGIN" or "{ORIGIN}". */
 724                 s = t + 7 + 2*(t[1]=='{');
 725         }
 726         strcpy(d, s);
 727         return 0;
 728 }
 729
 730 static void decode_dyn(struct dso *p)
 731 {
 732         size_t dyn[DYN_CNT];
 733         decode_vec(p->dynv, dyn, DYN_CNT);
 734         p->syms = laddr(p, dyn[DT_SYMTAB]);
 735         p->strings = laddr(p, dyn[DT_STRTAB]);
 736         if (dyn[0]&(1<<DT_HASH))
 737                 p->hashtab = laddr(p, dyn[DT_HASH]);
 738         if (dyn[0]&(1<<DT_RPATH))
 739                 p->rpath_orig = p->strings + dyn[DT_RPATH];
 740         if (dyn[0]&(1<<DT_RUNPATH))
 741                 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
 742         if (dyn[0]&(1<<DT_PLTGOT))
 743                 p->got = laddr(p, dyn[DT_PLTGOT]);
 744         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 745                 p->ghashtab = laddr(p, *dyn);
 746         if (search_vec(p->dynv, dyn, DT_VERSYM))
 747                 p->versym = laddr(p, *dyn);
 748 }
 749
 750 static size_t count_syms(struct dso *p)
 751 {
 752         if (p->hashtab) return p->hashtab[1];
 753
 754         size_t nsym, i;
 755         uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
 756         uint32_t *hashval;
 757         for (i = nsym = 0; i < p->ghashtab[0]; i++) {
 758                 if (buckets[i] > nsym)
 759                         nsym = buckets[i];
 760         }
 761         if (nsym) {
 762                 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
 763                 do nsym++;
 764                 while (!(*hashval++ & 1));
 765         }
 766         return nsym;
 767 }
 768
 769 static void *dl_mmap(size_t n)
 770 {
 771         void *p;
 772         int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
 773 #ifdef SYS_mmap2
 774         p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
 775 #else
 776         p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
 777 #endif
 778         return p == MAP_FAILED ? 0 : p;
 779 }
 780
 781 static void makefuncdescs(struct dso *p)
 782 {
 783         static int self_done;
 784         size_t nsym = count_syms(p);
 785         size_t i, size = nsym * sizeof(*p->funcdescs);
 786
 787         if (!self_done) {
 788                 p->funcdescs = dl_mmap(size);
 789                 self_done = 1;
 790         } else {
 791                 p->funcdescs = malloc(size);
 792         }
 793         if (!p->funcdescs) {
 794                 if (!runtime) a_crash();
 795                 error("Error allocating function descriptors for %s", p->name);
 796                 longjmp(*rtld_fail, 1);
 797         }
 798         for (i=0; i<nsym; i++) {
 799                 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
 800                         p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
 801                         p->funcdescs[i].got = p->got;
 802                 } else {
 803                         p->funcdescs[i].addr = 0;
 804                         p->funcdescs[i].got = 0;
 805                 }
 806         }
 807 }
 808
 809 static struct dso *load_library(const char *name, struct dso *needed_by)
 810 {
 811         char buf[2*NAME_MAX+2];
 812         const char *pathname;
 813         unsigned char *map;
 814         struct dso *p, temp_dso = {0};
 815         int fd;
 816         struct stat st;
 817         size_t alloc_size;
 818         int n_th = 0;
 819         int is_self = 0;
 820
 821         if (!*name) {
 822                 errno = EINVAL;
 823                 return 0;
 824         }
 825
 826         /* Catch and block attempts to reload the implementation itself */
 827         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 828                 static const char *rp, reserved[] =
 829                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 830                 char *z = strchr(name, '.');
 831                 if (z) {
 832                         size_t l = z-name;
 833                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 834                         if (*rp) {
 835                                 if (ldd_mode) {
 836                                         /* Track which names have been resolved
 837                                          * and only report each one once. */
 838                                         static unsigned reported;
 839                                         unsigned mask = 1U<<(rp-reserved);
 840                                         if (!(reported & mask)) {
 841                                                 reported |= mask;
 842                                                 dprintf(1, "\t%s => %s (%p)\n",
 843                                                         name, ldso.name,
 844                                                         ldso.base);
 845                                         }
 846                                 }
 847                                 is_self = 1;
 848                         }
 849                 }
 850         }
 851         if (!strcmp(name, ldso.name)) is_self = 1;
 852         if (is_self) {
 853                 if (!ldso.prev) {
 854                         tail->next = &ldso;
 855                         ldso.prev = tail;
 856                         tail = ldso.next ? ldso.next : &ldso;
 857                 }
 858                 return &ldso;
 859         }
 860         if (strchr(name, '/')) {
 861                 pathname = name;
 862                 fd = open(name, O_RDONLY|O_CLOEXEC);
 863         } else {
 864                 /* Search for the name to see if it's already loaded */
 865                 for (p=head->next; p; p=p->next) {
 866                         if (p->shortname && !strcmp(p->shortname, name)) {
 867                                 p->refcnt++;
 868                                 return p;
 869                         }
 870                 }
 871                 if (strlen(name) > NAME_MAX) return 0;
 872                 fd = -1;
 873                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 874                 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
 875                         if (fixup_rpath(p, buf, sizeof buf) < 0)
 876                                 fd = -2; /* Inhibit further search. */
 877                         if (p->rpath)
 878                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 879                 }
 880                 if (fd == -1) {
 881                         if (!sys_path) {
 882                                 char *prefix = 0;
 883                                 size_t prefix_len;
 884                                 if (ldso.name[0]=='/') {
 885                                         char *s, *t, *z;
 886                                         for (s=t=z=ldso.name; *s; s++)
 887                                                 if (*s=='/') z=t, t=s;
 888                                         prefix_len = z-ldso.name;
 889                                         if (prefix_len < PATH_MAX)
 890                                                 prefix = ldso.name;
 891                                 }
 892                                 if (!prefix) {
 893                                         prefix = "";
 894                                         prefix_len = 0;
 895                                 }
 896                                 char etc_ldso_path[prefix_len + 1
 897                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 898                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 899                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 900                                         (int)prefix_len, prefix);
 901                                 FILE *f = fopen(etc_ldso_path, "rbe");
 902                                 if (f) {
 903                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 904                                                 free(sys_path);
 905                                                 sys_path = "";
 906                                         }
 907                                         fclose(f);
 908                                 } else if (errno != ENOENT) {
 909                                         sys_path = "";
 910                                 }
 911                         }
 912                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 913                         fd = path_open(name, sys_path, buf, sizeof buf);
 914                 }
 915                 pathname = buf;
 916         }
 917         if (fd < 0) return 0;
 918         if (fstat(fd, &st) < 0) {
 919                 close(fd);
 920                 return 0;
 921         }
 922         for (p=head->next; p; p=p->next) {
 923                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 924                         /* If this library was previously loaded with a
 925                          * pathname but a search found the same inode,
 926                          * setup its shortname so it can be found by name. */
 927                         if (!p->shortname && pathname != name)
 928                                 p->shortname = strrchr(p->name, '/')+1;
 929                         close(fd);
 930                         p->refcnt++;
 931                         return p;
 932                 }
 933         }
 934         map = noload ? 0 : map_library(fd, &temp_dso);
 935         close(fd);
 936         if (!map) return 0;
 937
 938         /* Allocate storage for the new DSO. When there is TLS, this
 939          * storage must include a reservation for all pre-existing
 940          * threads to obtain copies of both the new TLS, and an
 941          * extended DTV capable of storing an additional slot for
 942          * the newly-loaded DSO. */
 943         alloc_size = sizeof *p + strlen(pathname) + 1;
 944         if (runtime && temp_dso.tls_image) {
 945                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 946                         + sizeof(void *) * (tls_cnt+3);
 947                 n_th = libc.threads_minus_1 + 1;
 948                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 949                 else alloc_size += n_th * per_th;
 950         }
 951         p = calloc(1, alloc_size);
 952         if (!p) {
 953                 munmap(map, temp_dso.map_len);
 954                 return 0;
 955         }
 956         memcpy(p, &temp_dso, sizeof temp_dso);
 957         decode_dyn(p);
 958         p->dev = st.st_dev;
 959         p->ino = st.st_ino;
 960         p->refcnt = 1;
 961         p->needed_by = needed_by;
 962         p->name = p->buf;
 963         strcpy(p->name, pathname);
 964         /* Add a shortname only if name arg was not an explicit pathname. */
 965         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 966         if (p->tls_image) {
 967                 p->tls_id = ++tls_cnt;
 968                 tls_align = MAXP2(tls_align, p->tls_align);
 969 #ifdef TLS_ABOVE_TP
 970                 p->tls_offset = tls_offset + ( (tls_align-1) &
 971                         -(tls_offset + (uintptr_t)p->tls_image) );
 972                 tls_offset += p->tls_size;
 973 #else
 974                 tls_offset += p->tls_size + p->tls_align - 1;
 975                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 976                         & (p->tls_align-1);
 977                 p->tls_offset = tls_offset;
 978 #endif
 979                 p->new_dtv = (void *)(-sizeof(size_t) &
 980                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 981                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 982         }
 983
 984         tail->next = p;
 985         p->prev = tail;
 986         tail = p;
 987
 988         if (DL_FDPIC) makefuncdescs(p);
 989
 990         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 991
 992         return p;
 993 }
 994
 995 static void load_deps(struct dso *p)
 996 {
 997         size_t i, ndeps=0;
 998         struct dso ***deps = &p->deps, **tmp, *dep;
 999         for (; p; p=p->next) {
1000                 for (i=0; p->dynv[i]; i+=2) {
1001                         if (p->dynv[i] != DT_NEEDED) continue;
1002                         dep = load_library(p->strings + p->dynv[i+1], p);
1003                         if (!dep) {
1004                                 error("Error loading shared library %s: %m (needed by %s)",
1005                                         p->strings + p->dynv[i+1], p->name);
1006                                 if (runtime) longjmp(*rtld_fail, 1);
1007                                 continue;
1008                         }
1009                         if (runtime) {
1010                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1011                                 if (!tmp) longjmp(*rtld_fail, 1);
1012                                 tmp[ndeps++] = dep;
1013                                 tmp[ndeps] = 0;
1014                                 *deps = tmp;
1015                         }
1016                 }
1017         }
1018 }
1019
1020 static void load_preload(char *s)
1021 {
1022         int tmp;
1023         char *z;
1024         for (z=s; *z; s=z) {
1025                 for (   ; *s && (isspace(*s) || *s==':'); s++);
1026                 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1027                 tmp = *z;
1028                 *z = 0;
1029                 load_library(s, 0);
1030                 *z = tmp;
1031         }
1032 }
1033
1034 static void make_global(struct dso *p)
1035 {
1036         for (; p; p=p->next) p->global = 1;
1037 }
1038
1039 static void do_mips_relocs(struct dso *p, size_t *got)
1040 {
1041         size_t i, j, rel[2];
1042         unsigned char *base = p->base;
1043         i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1044         if (p==&ldso) {
1045                 got += i;
1046         } else {
1047                 while (i--) *got++ += (size_t)base;
1048         }
1049         j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1050         i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1051         Sym *sym = p->syms + j;
1052         rel[0] = (unsigned char *)got - base;
1053         for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1054                 rel[1] = sym-p->syms << 8 | R_MIPS_JUMP_SLOT;
1055                 do_relocs(p, rel, sizeof rel, 2);
1056         }
1057 }
1058
1059 static void reloc_all(struct dso *p)
1060 {
1061         size_t dyn[DYN_CNT];
1062         for (; p; p=p->next) {
1063                 if (p->relocated) continue;
1064                 decode_vec(p->dynv, dyn, DYN_CNT);
1065                 if (NEED_MIPS_GOT_RELOCS)
1066                         do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1067                 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1068                         2+(dyn[DT_PLTREL]==DT_RELA));
1069                 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1070                 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1071
1072                 if (head != &ldso && p->relro_start != p->relro_end &&
1073                     mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1074                     && errno != ENOSYS) {
1075                         error("Error relocating %s: RELRO protection failed: %m",
1076                                 p->name);
1077                         if (runtime) longjmp(*rtld_fail, 1);
1078                 }
1079
1080                 p->relocated = 1;
1081         }
1082 }
1083
1084 static void kernel_mapped_dso(struct dso *p)
1085 {
1086         size_t min_addr = -1, max_addr = 0, cnt;
1087         Phdr *ph = p->phdr;
1088         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1089                 if (ph->p_type == PT_DYNAMIC) {
1090                         p->dynv = laddr(p, ph->p_vaddr);
1091                 } else if (ph->p_type == PT_GNU_RELRO) {
1092                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1093                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1094                 }
1095                 if (ph->p_type != PT_LOAD) continue;
1096                 if (ph->p_vaddr < min_addr)
1097                         min_addr = ph->p_vaddr;
1098                 if (ph->p_vaddr+ph->p_memsz > max_addr)
1099                         max_addr = ph->p_vaddr+ph->p_memsz;
1100         }
1101         min_addr &= -PAGE_SIZE;
1102         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1103         p->map = p->base + min_addr;
1104         p->map_len = max_addr - min_addr;
1105         p->kernel_mapped = 1;
1106 }
1107
1108 static void do_fini()
1109 {
1110         struct dso *p;
1111         size_t dyn[DYN_CNT];
1112         for (p=fini_head; p; p=p->fini_next) {
1113                 if (!p->constructed) continue;
1114                 decode_vec(p->dynv, dyn, DYN_CNT);
1115                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1116                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1117                         size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1118                         while (n--) ((void (*)(void))*--fn)();
1119                 }
1120 #ifndef NO_LEGACY_INITFINI
1121                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1122                         fpaddr(p, dyn[DT_FINI])();
1123 #endif
1124         }
1125 }
1126
1127 static void do_init_fini(struct dso *p)
1128 {
1129         size_t dyn[DYN_CNT];
1130         int need_locking = libc.threads_minus_1;
1131         /* Allow recursive calls that arise when a library calls
1132          * dlopen from one of its constructors, but block any
1133          * other threads until all ctors have finished. */
1134         if (need_locking) pthread_mutex_lock(&init_fini_lock);
1135         for (; p; p=p->prev) {
1136                 if (p->constructed) continue;
1137                 p->constructed = 1;
1138                 decode_vec(p->dynv, dyn, DYN_CNT);
1139                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1140                         p->fini_next = fini_head;
1141                         fini_head = p;
1142                 }
1143 #ifndef NO_LEGACY_INITFINI
1144                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1145                         fpaddr(p, dyn[DT_INIT])();
1146 #endif
1147                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1148                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1149                         size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1150                         while (n--) ((void (*)(void))*fn++)();
1151                 }
1152                 if (!need_locking && libc.threads_minus_1) {
1153                         need_locking = 1;
1154                         pthread_mutex_lock(&init_fini_lock);
1155                 }
1156         }
1157         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1158 }
1159
1160 static void dl_debug_state(void)
1161 {
1162 }
1163
1164 weak_alias(dl_debug_state, _dl_debug_state);
1165
1166 void __reset_tls()
1167 {
1168         pthread_t self = __pthread_self();
1169         struct dso *p;
1170         for (p=head; p; p=p->next) {
1171                 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
1172                 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
1173                 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
1174                         p->tls_size - p->tls_len);
1175                 if (p->tls_id == (size_t)self->dtv[0]) break;
1176         }
1177 }
1178
1179 void *__copy_tls(unsigned char *mem)
1180 {
1181         pthread_t td;
1182         struct dso *p;
1183         void **dtv;
1184
1185 #ifdef TLS_ABOVE_TP
1186         dtv = (void **)(mem + libc.tls_size) - (tls_cnt + 1);
1187
1188         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
1189         td = (pthread_t)mem;
1190         mem += sizeof(struct pthread);
1191
1192         for (p=head; p; p=p->next) {
1193                 if (!p->tls_id) continue;
1194                 dtv[p->tls_id] = mem + p->tls_offset;
1195                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1196         }
1197 #else
1198         dtv = (void **)mem;
1199
1200         mem += libc.tls_size - sizeof(struct pthread);
1201         mem -= (uintptr_t)mem & (tls_align-1);
1202         td = (pthread_t)mem;
1203
1204         for (p=head; p; p=p->next) {
1205                 if (!p->tls_id) continue;
1206                 dtv[p->tls_id] = mem - p->tls_offset;
1207                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1208         }
1209 #endif
1210         dtv[0] = (void *)tls_cnt;
1211         td->dtv = td->dtv_copy = dtv;
1212         return td;
1213 }
1214
1215 __attribute__((__visibility__("hidden")))
1216 void *__tls_get_new(size_t *v)
1217 {
1218         pthread_t self = __pthread_self();
1219
1220         /* Block signals to make accessing new TLS async-signal-safe */
1221         sigset_t set;
1222         __block_all_sigs(&set);
1223         if (v[0]<=(size_t)self->dtv[0]) {
1224                 __restore_sigs(&set);
1225                 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1226         }
1227
1228         /* This is safe without any locks held because, if the caller
1229          * is able to request the Nth entry of the DTV, the DSO list
1230          * must be valid at least that far out and it was synchronized
1231          * at program startup or by an already-completed call to dlopen. */
1232         struct dso *p;
1233         for (p=head; p->tls_id != v[0]; p=p->next);
1234
1235         /* Get new DTV space from new DSO if needed */
1236         if (v[0] > (size_t)self->dtv[0]) {
1237                 void **newdtv = p->new_dtv +
1238                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1239                 memcpy(newdtv, self->dtv,
1240                         ((size_t)self->dtv[0]+1) * sizeof(void *));
1241                 newdtv[0] = (void *)v[0];
1242                 self->dtv = self->dtv_copy = newdtv;
1243         }
1244
1245         /* Get new TLS memory from all new DSOs up to the requested one */
1246         unsigned char *mem;
1247         for (p=head; ; p=p->next) {
1248                 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1249                 mem = p->new_tls + (p->tls_size + p->tls_align)
1250                         * a_fetch_add(&p->new_tls_idx,1);
1251                 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
1252                         & (p->tls_align-1);
1253                 self->dtv[p->tls_id] = mem;
1254                 memcpy(mem, p->tls_image, p->tls_len);
1255                 if (p->tls_id == v[0]) break;
1256         }
1257         __restore_sigs(&set);
1258         return mem + v[1] + DTP_OFFSET;
1259 }
1260
1261 static void update_tls_size()
1262 {
1263         libc.tls_size = ALIGN(
1264                 (1+tls_cnt) * sizeof(void *) +
1265                 tls_offset +
1266                 sizeof(struct pthread) +
1267                 tls_align * 2,
1268         tls_align);
1269 }
1270
1271 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1272  * following stage 2 and stage 3 functions via primitive symbolic lookup
1273  * since it does not have access to their addresses to begin with. */
1274
1275 /* Stage 2 of the dynamic linker is called after relative relocations
1276  * have been processed. It can make function calls to static functions
1277  * and access string literals and static data, but cannot use extern
1278  * symbols. Its job is to perform symbolic relocations on the dynamic
1279  * linker itself, but some of the relocations performed may need to be
1280  * replaced later due to copy relocations in the main program. */
1281
1282 void __dls2(unsigned char *base, size_t *sp)
1283 {
1284         if (DL_FDPIC) {
1285                 void *p1 = (void *)sp[-2];
1286                 void *p2 = (void *)sp[-1];
1287                 if (!p1) {
1288                         size_t *auxv, aux[AUX_CNT];
1289                         for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1290                         decode_vec(auxv, aux, AUX_CNT);
1291                         if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1292                         else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1293                 }
1294                 app_loadmap = p2 ? p1 : 0;
1295                 ldso.loadmap = p2 ? p2 : p1;
1296                 ldso.base = laddr(&ldso, 0);
1297         } else {
1298                 ldso.base = base;
1299         }
1300         Ehdr *ehdr = (void *)ldso.base;
1301         ldso.name = ldso.shortname = "libc.so";
1302         ldso.global = 1;
1303         ldso.phnum = ehdr->e_phnum;
1304         ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1305         ldso.phentsize = ehdr->e_phentsize;
1306         kernel_mapped_dso(&ldso);
1307         decode_dyn(&ldso);
1308
1309         if (DL_FDPIC) makefuncdescs(&ldso);
1310
1311         /* Prepare storage for to save clobbered REL addends so they
1312          * can be reused in stage 3. There should be very few. If
1313          * something goes wrong and there are a huge number, abort
1314          * instead of risking stack overflow. */
1315         size_t dyn[DYN_CNT];
1316         decode_vec(ldso.dynv, dyn, DYN_CNT);
1317         size_t *rel = laddr(&ldso, dyn[DT_REL]);
1318         size_t rel_size = dyn[DT_RELSZ];
1319         size_t symbolic_rel_cnt = 0;
1320         apply_addends_to = rel;
1321         for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1322                 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1323         if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1324         size_t addends[symbolic_rel_cnt+1];
1325         saved_addends = addends;
1326
1327         head = &ldso;
1328         reloc_all(&ldso);
1329
1330         ldso.relocated = 0;
1331
1332         /* Call dynamic linker stage-3, __dls3, looking it up
1333          * symbolically as a barrier against moving the address
1334          * load across the above relocation processing. */
1335         struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1336         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1337         else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1338 }
1339
1340 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1341  * fully functional. Its job is to load (if not already loaded) and
1342  * process dependencies and relocations for the main application and
1343  * transfer control to its entry point. */
1344
1345 _Noreturn void __dls3(size_t *sp)
1346 {
1347         static struct dso app, vdso;
1348         size_t aux[AUX_CNT], *auxv;
1349         size_t i;
1350         char *env_preload=0;
1351         size_t vdso_base;
1352         int argc = *sp;
1353         char **argv = (void *)(sp+1);
1354         char **argv_orig = argv;
1355         char **envp = argv+argc+1;
1356
1357         /* Find aux vector just past environ[] and use it to initialize
1358          * global data that may be needed before we can make syscalls. */
1359         __environ = envp;
1360         for (i=argc+1; argv[i]; i++);
1361         libc.auxv = auxv = (void *)(argv+i+1);
1362         decode_vec(auxv, aux, AUX_CNT);
1363         __hwcap = aux[AT_HWCAP];
1364         libc.page_size = aux[AT_PAGESZ];
1365         libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1366                 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1367
1368         /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1369          * use during dynamic linking. If possible it will also serve as the
1370          * thread pointer at runtime. */
1371         libc.tls_size = sizeof builtin_tls;
1372         if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1373                 a_crash();
1374         }
1375
1376         /* Only trust user/env if kernel says we're not suid/sgid */
1377         if (!libc.secure) {
1378                 env_path = getenv("LD_LIBRARY_PATH");
1379                 env_preload = getenv("LD_PRELOAD");
1380         }
1381
1382         /* If the main program was already loaded by the kernel,
1383          * AT_PHDR will point to some location other than the dynamic
1384          * linker's program headers. */
1385         if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1386                 size_t interp_off = 0;
1387                 size_t tls_image = 0;
1388                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1389                 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1390                 app.phnum = aux[AT_PHNUM];
1391                 app.phentsize = aux[AT_PHENT];
1392                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1393                         if (phdr->p_type == PT_PHDR)
1394                                 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1395                         else if (phdr->p_type == PT_INTERP)
1396                                 interp_off = (size_t)phdr->p_vaddr;
1397                         else if (phdr->p_type == PT_TLS) {
1398                                 tls_image = phdr->p_vaddr;
1399                                 app.tls_len = phdr->p_filesz;
1400                                 app.tls_size = phdr->p_memsz;
1401                                 app.tls_align = phdr->p_align;
1402                         }
1403                 }
1404                 if (DL_FDPIC) app.loadmap = app_loadmap;
1405                 if (app.tls_size) app.tls_image = laddr(&app, tls_image);
1406                 if (interp_off) ldso.name = laddr(&app, interp_off);
1407                 if ((aux[0] & (1UL<<AT_EXECFN))
1408                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1409                         app.name = (char *)aux[AT_EXECFN];
1410                 else
1411                         app.name = argv[0];
1412                 kernel_mapped_dso(&app);
1413         } else {
1414                 int fd;
1415                 char *ldname = argv[0];
1416                 size_t l = strlen(ldname);
1417                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1418                 argv++;
1419                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1420                         char *opt = argv[0]+2;
1421                         *argv++ = (void *)-1;
1422                         if (!*opt) {
1423                                 break;
1424                         } else if (!memcmp(opt, "list", 5)) {
1425                                 ldd_mode = 1;
1426                         } else if (!memcmp(opt, "library-path", 12)) {
1427                                 if (opt[12]=='=') env_path = opt+13;
1428                                 else if (opt[12]) *argv = 0;
1429                                 else if (*argv) env_path = *argv++;
1430                         } else if (!memcmp(opt, "preload", 7)) {
1431                                 if (opt[7]=='=') env_preload = opt+8;
1432                                 else if (opt[7]) *argv = 0;
1433                                 else if (*argv) env_preload = *argv++;
1434                         } else {
1435                                 argv[0] = 0;
1436                         }
1437                 }
1438                 argv[-1] = (void *)(argc - (argv-argv_orig));
1439                 if (!argv[0]) {
1440                         dprintf(2, "musl libc\n"
1441                                 "Version %s\n"
1442                                 "Dynamic Program Loader\n"
1443                                 "Usage: %s [options] [--] pathname%s\n",
1444                                 __libc_get_version(), ldname,
1445                                 ldd_mode ? "" : " [args]");
1446                         _exit(1);
1447                 }
1448                 fd = open(argv[0], O_RDONLY);
1449                 if (fd < 0) {
1450                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1451                         _exit(1);
1452                 }
1453                 runtime = 1;
1454                 Ehdr *ehdr = (void *)map_library(fd, &app);
1455                 if (!ehdr) {
1456                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1457                         _exit(1);
1458                 }
1459                 runtime = 0;
1460                 close(fd);
1461                 ldso.name = ldname;
1462                 app.name = argv[0];
1463                 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1464                 /* Find the name that would have been used for the dynamic
1465                  * linker had ldd not taken its place. */
1466                 if (ldd_mode) {
1467                         for (i=0; i<app.phnum; i++) {
1468                                 if (app.phdr[i].p_type == PT_INTERP)
1469                                         ldso.name = (void *)(app.base
1470                                                 + app.phdr[i].p_vaddr);
1471                         }
1472                         dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1473                 }
1474         }
1475         if (app.tls_size) {
1476                 app.tls_id = tls_cnt = 1;
1477 #ifdef TLS_ABOVE_TP
1478                 app.tls_offset = 0;
1479                 tls_offset = app.tls_size
1480                         + ( -((uintptr_t)app.tls_image + app.tls_size)
1481                         & (app.tls_align-1) );
1482 #else
1483                 tls_offset = app.tls_offset = app.tls_size
1484                         + ( -((uintptr_t)app.tls_image + app.tls_size)
1485                         & (app.tls_align-1) );
1486 #endif
1487                 tls_align = MAXP2(tls_align, app.tls_align);
1488         }
1489         app.global = 1;
1490         decode_dyn(&app);
1491         if (DL_FDPIC) {
1492                 makefuncdescs(&app);
1493                 if (!app.loadmap) {
1494                         app.loadmap = (void *)&app_dummy_loadmap;
1495                         app.loadmap->nsegs = 1;
1496                         app.loadmap->segs[0].addr = (size_t)app.base;
1497                         app.loadmap->segs[0].p_memsz = -1;
1498                 }
1499                 argv[-3] = (void *)app.loadmap;
1500         }
1501
1502         /* Attach to vdso, if provided by the kernel */
1503         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1504                 Ehdr *ehdr = (void *)vdso_base;
1505                 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1506                 vdso.phnum = ehdr->e_phnum;
1507                 vdso.phentsize = ehdr->e_phentsize;
1508                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1509                         if (phdr->p_type == PT_DYNAMIC)
1510                                 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1511                         if (phdr->p_type == PT_LOAD)
1512                                 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1513                 }
1514                 vdso.name = "";
1515                 vdso.shortname = "linux-gate.so.1";
1516                 vdso.global = 1;
1517                 vdso.relocated = 1;
1518                 decode_dyn(&vdso);
1519                 vdso.prev = &ldso;
1520                 ldso.next = &vdso;
1521         }
1522
1523         /* Initial dso chain consists only of the app. */
1524         head = tail = &app;
1525
1526         /* Donate unused parts of app and library mapping to malloc */
1527         reclaim_gaps(&app);
1528         reclaim_gaps(&ldso);
1529
1530         /* Load preload/needed libraries, add their symbols to the global
1531          * namespace, and perform all remaining relocations. */
1532         if (env_preload) load_preload(env_preload);
1533         load_deps(&app);
1534         make_global(&app);
1535
1536 #ifndef DYNAMIC_IS_RO
1537         for (i=0; app.dynv[i]; i+=2)
1538                 if (app.dynv[i]==DT_DEBUG)
1539                         app.dynv[i+1] = (size_t)&debug;
1540 #endif
1541
1542         /* The main program must be relocated LAST since it may contin
1543          * copy relocations which depend on libraries' relocations. */
1544         reloc_all(app.next);
1545         reloc_all(&app);
1546
1547         update_tls_size();
1548         if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1549                 void *initial_tls = calloc(libc.tls_size, 1);
1550                 if (!initial_tls) {
1551                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1552                                 argv[0], libc.tls_size);
1553                         _exit(127);
1554                 }
1555                 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1556                         a_crash();
1557                 }
1558         } else {
1559                 size_t tmp_tls_size = libc.tls_size;
1560                 pthread_t self = __pthread_self();
1561                 /* Temporarily set the tls size to the full size of
1562                  * builtin_tls so that __copy_tls will use the same layout
1563                  * as it did for before. Then check, just to be safe. */
1564                 libc.tls_size = sizeof builtin_tls;
1565                 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1566                 libc.tls_size = tmp_tls_size;
1567         }
1568         static_tls_cnt = tls_cnt;
1569
1570         if (ldso_fail) _exit(127);
1571         if (ldd_mode) _exit(0);
1572
1573         /* Switch to runtime mode: any further failures in the dynamic
1574          * linker are a reportable failure rather than a fatal startup
1575          * error. */
1576         runtime = 1;
1577
1578         debug.ver = 1;
1579         debug.bp = dl_debug_state;
1580         debug.head = head;
1581         debug.base = ldso.base;
1582         debug.state = 0;
1583         _dl_debug_state();
1584
1585         __init_libc(envp, argv[0]);
1586         atexit(do_fini);
1587         errno = 0;
1588         do_init_fini(tail);
1589
1590         CRTJMP((void *)aux[AT_ENTRY], argv-1);
1591         for(;;);
1592 }
1593
1594 void *dlopen(const char *file, int mode)
1595 {
1596         struct dso *volatile p, *orig_tail, *next;
1597         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1598         size_t i;
1599         int cs;
1600         jmp_buf jb;
1601
1602         if (!file) return head;
1603
1604         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1605         pthread_rwlock_wrlock(&lock);
1606         __inhibit_ptc();
1607
1608         p = 0;
1609         orig_tls_cnt = tls_cnt;
1610         orig_tls_offset = tls_offset;
1611         orig_tls_align = tls_align;
1612         orig_tail = tail;
1613         noload = mode & RTLD_NOLOAD;
1614
1615         rtld_fail = &jb;
1616         if (setjmp(*rtld_fail)) {
1617                 /* Clean up anything new that was (partially) loaded */
1618                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1619                         if (p->deps[i]->global < 0)
1620                                 p->deps[i]->global = 0;
1621                 for (p=orig_tail->next; p; p=next) {
1622                         next = p->next;
1623                         munmap(p->map, p->map_len);
1624                         while (p->td_index) {
1625                                 void *tmp = p->td_index->next;
1626                                 free(p->td_index);
1627                                 p->td_index = tmp;
1628                         }
1629                         if (p->funcdescs)
1630                                 free(p->funcdescs);
1631                         if (p->rpath != p->rpath_orig)
1632                                 free(p->rpath);
1633                         free(p->deps);
1634                         free(p);
1635                 }
1636                 tls_cnt = orig_tls_cnt;
1637                 tls_offset = orig_tls_offset;
1638                 tls_align = orig_tls_align;
1639                 tail = orig_tail;
1640                 tail->next = 0;
1641                 p = 0;
1642                 goto end;
1643         } else p = load_library(file, head);
1644
1645         if (!p) {
1646                 error(noload ?
1647                         "Library %s is not already loaded" :
1648                         "Error loading shared library %s: %m",
1649                         file);
1650                 goto end;
1651         }
1652
1653         /* First load handling */
1654         if (!p->deps) {
1655                 load_deps(p);
1656                 if (p->deps) for (i=0; p->deps[i]; i++)
1657                         if (!p->deps[i]->global)
1658                                 p->deps[i]->global = -1;
1659                 if (!p->global) p->global = -1;
1660                 reloc_all(p);
1661                 if (p->deps) for (i=0; p->deps[i]; i++)
1662                         if (p->deps[i]->global < 0)
1663                                 p->deps[i]->global = 0;
1664                 if (p->global < 0) p->global = 0;
1665         }
1666
1667         if (mode & RTLD_GLOBAL) {
1668                 if (p->deps) for (i=0; p->deps[i]; i++)
1669                         p->deps[i]->global = 1;
1670                 p->global = 1;
1671         }
1672
1673         update_tls_size();
1674         _dl_debug_state();
1675         orig_tail = tail;
1676 end:
1677         __release_ptc();
1678         if (p) gencnt++;
1679         pthread_rwlock_unlock(&lock);
1680         if (p) do_init_fini(orig_tail);
1681         pthread_setcancelstate(cs, 0);
1682         return p;
1683 }
1684
1685 static int invalid_dso_handle(void *h)
1686 {
1687         struct dso *p;
1688         for (p=head; p; p=p->next) if (h==p) return 0;
1689         error("Invalid library handle %p", (void *)h);
1690         return 1;
1691 }
1692
1693 void *__tls_get_addr(size_t *);
1694
1695 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1696 {
1697         size_t i;
1698         uint32_t h = 0, gh = 0, *ght;
1699         Sym *sym;
1700         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1701                 if (p == RTLD_DEFAULT) {
1702                         p = head;
1703                 } else if (p == RTLD_NEXT) {
1704                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1705                         if (!p) p=head;
1706                         p = p->next;
1707                 }
1708                 struct symdef def = find_sym(p, s, 0);
1709                 if (!def.sym) goto failed;
1710                 if ((def.sym->st_info&0xf) == STT_TLS)
1711                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1712                 return laddr(def.dso, def.sym->st_value);
1713         }
1714         if (invalid_dso_handle(p))
1715                 return 0;
1716         if ((ght = p->ghashtab)) {
1717                 gh = gnu_hash(s);
1718                 sym = gnu_lookup(gh, ght, p, s);
1719         } else {
1720                 h = sysv_hash(s);
1721                 sym = sysv_lookup(s, h, p);
1722         }
1723         if (sym && (sym->st_info&0xf) == STT_TLS)
1724                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1725         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1726                 return laddr(p, sym->st_value);
1727         if (p->deps) for (i=0; p->deps[i]; i++) {
1728                 if ((ght = p->deps[i]->ghashtab)) {
1729                         if (!gh) gh = gnu_hash(s);
1730                         sym = gnu_lookup(gh, ght, p->deps[i], s);
1731                 } else {
1732                         if (!h) h = sysv_hash(s);
1733                         sym = sysv_lookup(s, h, p->deps[i]);
1734                 }
1735                 if (sym && (sym->st_info&0xf) == STT_TLS)
1736                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1737                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1738                         return laddr(p->deps[i], sym->st_value);
1739         }
1740 failed:
1741         error("Symbol not found: %s", s);
1742         return 0;
1743 }
1744
1745 int __dladdr(const void *addr, Dl_info *info)
1746 {
1747         struct dso *p;
1748         Sym *sym;
1749         uint32_t nsym;
1750         char *strings;
1751         void *best = 0;
1752         char *bestname;
1753
1754         pthread_rwlock_rdlock(&lock);
1755         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1756         pthread_rwlock_unlock(&lock);
1757
1758         if (!p) return 0;
1759
1760         sym = p->syms;
1761         strings = p->strings;
1762         nsym = count_syms(p);
1763
1764         for (; nsym; nsym--, sym++) {
1765                 if (sym->st_value
1766                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1767                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1768                         void *symaddr = laddr(p, sym->st_value);
1769                         if (symaddr > addr || symaddr < best)
1770                                 continue;
1771                         best = symaddr;
1772                         bestname = strings + sym->st_name;
1773                         if (addr == symaddr)
1774                                 break;
1775                 }
1776         }
1777
1778         if (!best) return 0;
1779
1780         info->dli_fname = p->name;
1781         info->dli_fbase = p->base;
1782         info->dli_sname = bestname;
1783         info->dli_saddr = best;
1784
1785         return 1;
1786 }
1787
1788 __attribute__((__visibility__("hidden")))
1789 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1790 {
1791         void *res;
1792         pthread_rwlock_rdlock(&lock);
1793         res = do_dlsym(p, s, ra);
1794         pthread_rwlock_unlock(&lock);
1795         return res;
1796 }
1797
1798 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1799 {
1800         struct dso *current;
1801         struct dl_phdr_info info;
1802         int ret = 0;
1803         for(current = head; current;) {
1804                 info.dlpi_addr      = (uintptr_t)current->base;
1805                 info.dlpi_name      = current->name;
1806                 info.dlpi_phdr      = current->phdr;
1807                 info.dlpi_phnum     = current->phnum;
1808                 info.dlpi_adds      = gencnt;
1809                 info.dlpi_subs      = 0;
1810                 info.dlpi_tls_modid = current->tls_id;
1811                 info.dlpi_tls_data  = current->tls_image;
1812
1813                 ret = (callback)(&info, sizeof (info), data);
1814
1815                 if (ret != 0) break;
1816
1817                 pthread_rwlock_rdlock(&lock);
1818                 current = current->next;
1819                 pthread_rwlock_unlock(&lock);
1820         }
1821         return ret;
1822 }
1823 #else
1824 static int invalid_dso_handle(void *h)
1825 {
1826         error("Invalid library handle %p", (void *)h);
1827         return 1;
1828 }
1829 void *dlopen(const char *file, int mode)
1830 {
1831         error("Dynamic loading not supported");
1832         return 0;
1833 }
1834 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1835 {
1836         error("Symbol not found: %s", s);
1837         return 0;
1838 }
1839 int __dladdr (const void *addr, Dl_info *info)
1840 {
1841         return 0;
1842 }
1843 #endif
1844
1845 int __dlinfo(void *dso, int req, void *res)
1846 {
1847         if (invalid_dso_handle(dso)) return -1;
1848         if (req != RTLD_DI_LINKMAP) {
1849                 error("Unsupported request %d", req);
1850                 return -1;
1851         }
1852         *(struct link_map **)res = dso;
1853         return 0;
1854 }
1855
1856 char *dlerror()
1857 {
1858         pthread_t self = __pthread_self();
1859         if (!self->dlerror_flag) return 0;
1860         self->dlerror_flag = 0;
1861         char *s = self->dlerror_buf;
1862         if (s == (void *)-1)
1863                 return "Dynamic linker failed to allocate memory for error message";
1864         else
1865                 return s;
1866 }
1867
1868 int dlclose(void *p)
1869 {
1870         return invalid_dso_handle(p);
1871 }
1872
1873 void __dl_thread_cleanup(void)
1874 {
1875         pthread_t self = __pthread_self();
1876         if (self->dlerror_buf != (void *)-1)
1877                 free(self->dlerror_buf);
1878 }
1879
1880 static void error(const char *fmt, ...)
1881 {
1882         va_list ap;
1883         va_start(ap, fmt);
1884 #ifdef SHARED
1885         if (!runtime) {
1886                 vdprintf(2, fmt, ap);
1887                 dprintf(2, "\n");
1888                 ldso_fail = 1;
1889                 va_end(ap);
1890                 return;
1891         }
1892 #endif
1893         pthread_t self = __pthread_self();
1894         if (self->dlerror_buf != (void *)-1)
1895                 free(self->dlerror_buf);
1896         size_t len = vsnprintf(0, 0, fmt, ap);
1897         va_end(ap);
1898         char *buf = malloc(len+1);
1899         if (buf) {
1900                 va_start(ap, fmt);
1901                 vsnprintf(buf, len+1, fmt, ap);
1902                 va_end(ap);
1903         } else {
1904                 buf = (void *)-1;
1905         }
1906         self->dlerror_buf = buf;
1907         self->dlerror_flag = 1;
1908 }