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

   1 #define _GNU_SOURCE
   2 #define SYSCALL_NO_TLS 1
   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 <semaphore.h>
  21 #include <sys/membarrier.h>
  22 #include "pthread_impl.h"
  23 #include "fork_impl.h"
  24 #include "dynlink.h"
  25
  26 static size_t ldso_page_size;
  27 #ifndef PAGE_SIZE
  28 #define PAGE_SIZE ldso_page_size
  29 #endif
  30
  31 #include "libc.h"
  32
  33 #define malloc __libc_malloc
  34 #define calloc __libc_calloc
  35 #define realloc __libc_realloc
  36 #define free __libc_free
  37
  38 static void error_impl(const char *, ...);
  39 static void error_noop(const char *, ...);
  40 static void (*error)(const char *, ...) = error_noop;
  41
  42 #define MAXP2(a,b) (-(-(a)&-(b)))
  43 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  44
  45 #define container_of(p,t,m) ((t*)((char *)(p)-offsetof(t,m)))
  46 #define countof(a) ((sizeof (a))/(sizeof (a)[0]))
  47
  48 struct debug {
  49         int ver;
  50         void *head;
  51         void (*bp)(void);
  52         int state;
  53         void *base;
  54 };
  55
  56 struct td_index {
  57         size_t args[2];
  58         struct td_index *next;
  59 };
  60
  61 struct dso {
  62 #if DL_FDPIC
  63         struct fdpic_loadmap *loadmap;
  64 #else
  65         unsigned char *base;
  66 #endif
  67         char *name;
  68         size_t *dynv;
  69         struct dso *next, *prev;
  70
  71         Phdr *phdr;
  72         int phnum;
  73         size_t phentsize;
  74         Sym *syms;
  75         Elf_Symndx *hashtab;
  76         uint32_t *ghashtab;
  77         int16_t *versym;
  78         char *strings;
  79         struct dso *syms_next, *lazy_next;
  80         size_t *lazy, lazy_cnt;
  81         unsigned char *map;
  82         size_t map_len;
  83         dev_t dev;
  84         ino_t ino;
  85         char relocated;
  86         char constructed;
  87         char kernel_mapped;
  88         char mark;
  89         char bfs_built;
  90         char runtime_loaded;
  91         struct dso **deps, *needed_by;
  92         size_t ndeps_direct;
  93         size_t next_dep;
  94         pthread_t ctor_visitor;
  95         char *rpath_orig, *rpath;
  96         struct tls_module tls;
  97         size_t tls_id;
  98         size_t relro_start, relro_end;
  99         uintptr_t *new_dtv;
 100         unsigned char *new_tls;
 101         struct td_index *td_index;
 102         struct dso *fini_next;
 103         char *shortname;
 104 #if DL_FDPIC
 105         unsigned char *base;
 106 #else
 107         struct fdpic_loadmap *loadmap;
 108 #endif
 109         struct funcdesc {
 110                 void *addr;
 111                 size_t *got;
 112         } *funcdescs;
 113         size_t *got;
 114         char buf[];
 115 };
 116
 117 struct symdef {
 118         Sym *sym;
 119         struct dso *dso;
 120 };
 121
 122 typedef void (*stage3_func)(size_t *, size_t *);
 123
 124 static struct builtin_tls {
 125         char c;
 126         struct pthread pt;
 127         void *space[16];
 128 } builtin_tls[1];
 129 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
 130
 131 #define ADDEND_LIMIT 4096
 132 static size_t *saved_addends, *apply_addends_to;
 133
 134 static struct dso ldso;
 135 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
 136 static char *env_path, *sys_path;
 137 static unsigned long long gencnt;
 138 static int runtime;
 139 static int ldd_mode;
 140 static int ldso_fail;
 141 static int noload;
 142 static int shutting_down;
 143 static jmp_buf *rtld_fail;
 144 static pthread_rwlock_t lock;
 145 static struct debug debug;
 146 static struct tls_module *tls_tail;
 147 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
 148 static size_t static_tls_cnt;
 149 static pthread_mutex_t init_fini_lock;
 150 static pthread_cond_t ctor_cond;
 151 static struct dso *builtin_deps[2];
 152 static struct dso *const no_deps[1];
 153 static struct dso *builtin_ctor_queue[4];
 154 static struct dso **main_ctor_queue;
 155 static struct fdpic_loadmap *app_loadmap;
 156 static struct fdpic_dummy_loadmap app_dummy_loadmap;
 157
 158 struct debug *_dl_debug_addr = &debug;
 159
 160 extern hidden int __malloc_replaced;
 161
 162 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
 163
 164 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
 165
 166 weak_alias(__init_array_start, __init_array_end);
 167 weak_alias(__fini_array_start, __fini_array_end);
 168
 169 static int dl_strcmp(const char *l, const char *r)
 170 {
 171         for (; *l==*r && *l; l++, r++);
 172         return *(unsigned char *)l - *(unsigned char *)r;
 173 }
 174 #define strcmp(l,r) dl_strcmp(l,r)
 175
 176 /* Compute load address for a virtual address in a given dso. */
 177 #if DL_FDPIC
 178 static void *laddr(const struct dso *p, size_t v)
 179 {
 180         size_t j=0;
 181         if (!p->loadmap) return p->base + v;
 182         for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
 183         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 184 }
 185 static void *laddr_pg(const struct dso *p, size_t v)
 186 {
 187         size_t j=0;
 188         size_t pgsz = PAGE_SIZE;
 189         if (!p->loadmap) return p->base + v;
 190         for (j=0; ; j++) {
 191                 size_t a = p->loadmap->segs[j].p_vaddr;
 192                 size_t b = a + p->loadmap->segs[j].p_memsz;
 193                 a &= -pgsz;
 194                 b += pgsz-1;
 195                 b &= -pgsz;
 196                 if (v-a<b-a) break;
 197         }
 198         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 199 }
 200 static void (*fdbarrier(void *p))()
 201 {
 202         void (*fd)();
 203         __asm__("" : "=r"(fd) : "0"(p));
 204         return fd;
 205 }
 206 #define fpaddr(p, v) fdbarrier((&(struct funcdesc){ \
 207         laddr(p, v), (p)->got }))
 208 #else
 209 #define laddr(p, v) (void *)((p)->base + (v))
 210 #define laddr_pg(p, v) laddr(p, v)
 211 #define fpaddr(p, v) ((void (*)())laddr(p, v))
 212 #endif
 213
 214 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 215 {
 216         size_t i;
 217         for (i=0; i<cnt; i++) a[i] = 0;
 218         for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
 219                 if (v[0] < 8*sizeof(long))
 220                         a[0] |= 1UL<<v[0];
 221                 a[v[0]] = v[1];
 222         }
 223 }
 224
 225 static int search_vec(size_t *v, size_t *r, size_t key)
 226 {
 227         for (; v[0]!=key; v+=2)
 228                 if (!v[0]) return 0;
 229         *r = v[1];
 230         return 1;
 231 }
 232
 233 static uint32_t sysv_hash(const char *s0)
 234 {
 235         const unsigned char *s = (void *)s0;
 236         uint_fast32_t h = 0;
 237         while (*s) {
 238                 h = 16*h + *s++;
 239                 h ^= h>>24 & 0xf0;
 240         }
 241         return h & 0xfffffff;
 242 }
 243
 244 static uint32_t gnu_hash(const char *s0)
 245 {
 246         const unsigned char *s = (void *)s0;
 247         uint_fast32_t h = 5381;
 248         for (; *s; s++)
 249                 h += h*32 + *s;
 250         return h;
 251 }
 252
 253 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 254 {
 255         size_t i;
 256         Sym *syms = dso->syms;
 257         Elf_Symndx *hashtab = dso->hashtab;
 258         char *strings = dso->strings;
 259         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 260                 if ((!dso->versym || dso->versym[i] >= 0)
 261                     && (!strcmp(s, strings+syms[i].st_name)))
 262                         return syms+i;
 263         }
 264         return 0;
 265 }
 266
 267 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
 268 {
 269         uint32_t nbuckets = hashtab[0];
 270         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 271         uint32_t i = buckets[h1 % nbuckets];
 272
 273         if (!i) return 0;
 274
 275         uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
 276
 277         for (h1 |= 1; ; i++) {
 278                 uint32_t h2 = *hashval++;
 279                 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
 280                     && !strcmp(s, dso->strings + dso->syms[i].st_name))
 281                         return dso->syms+i;
 282                 if (h2 & 1) break;
 283         }
 284
 285         return 0;
 286 }
 287
 288 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
 289 {
 290         const size_t *bloomwords = (const void *)(hashtab+4);
 291         size_t f = bloomwords[fofs & (hashtab[2]-1)];
 292         if (!(f & fmask)) return 0;
 293
 294         f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
 295         if (!(f & 1)) return 0;
 296
 297         return gnu_lookup(h1, hashtab, dso, s);
 298 }
 299
 300 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 301 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 302
 303 #ifndef ARCH_SYM_REJECT_UND
 304 #define ARCH_SYM_REJECT_UND(s) 0
 305 #endif
 306
 307 #if defined(__GNUC__)
 308 __attribute__((always_inline))
 309 #endif
 310 static inline struct symdef find_sym2(struct dso *dso, const char *s, int need_def, int use_deps)
 311 {
 312         uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
 313         size_t ghm = 1ul << gh % (8*sizeof(size_t));
 314         struct symdef def = {0};
 315         struct dso **deps = use_deps ? dso->deps : 0;
 316         for (; dso; dso=use_deps ? *deps++ : dso->syms_next) {
 317                 Sym *sym;
 318                 if ((ght = dso->ghashtab)) {
 319                         sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
 320                 } else {
 321                         if (!h) h = sysv_hash(s);
 322                         sym = sysv_lookup(s, h, dso);
 323                 }
 324                 if (!sym) continue;
 325                 if (!sym->st_shndx)
 326                         if (need_def || (sym->st_info&0xf) == STT_TLS
 327                             || ARCH_SYM_REJECT_UND(sym))
 328                                 continue;
 329                 if (!sym->st_value)
 330                         if ((sym->st_info&0xf) != STT_TLS)
 331                                 continue;
 332                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 333                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 334                 def.sym = sym;
 335                 def.dso = dso;
 336                 break;
 337         }
 338         return def;
 339 }
 340
 341 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 342 {
 343         return find_sym2(dso, s, need_def, 0);
 344 }
 345
 346 static struct symdef get_lfs64(const char *name)
 347 {
 348         const char *p;
 349         static const char lfs64_list[] =
 350                 "aio_cancel\0aio_error\0aio_fsync\0aio_read\0aio_return\0"
 351                 "aio_suspend\0aio_write\0alphasort\0creat\0fallocate\0"
 352                 "fgetpos\0fopen\0freopen\0fseeko\0fsetpos\0fstat\0"
 353                 "fstatat\0fstatfs\0fstatvfs\0ftello\0ftruncate\0ftw\0"
 354                 "getdents\0getrlimit\0glob\0globfree\0lio_listio\0"
 355                 "lockf\0lseek\0lstat\0mkostemp\0mkostemps\0mkstemp\0"
 356                 "mkstemps\0mmap\0nftw\0open\0openat\0posix_fadvise\0"
 357                 "posix_fallocate\0pread\0preadv\0prlimit\0pwrite\0"
 358                 "pwritev\0readdir\0scandir\0sendfile\0setrlimit\0"
 359                 "stat\0statfs\0statvfs\0tmpfile\0truncate\0versionsort\0"
 360                 "__fxstat\0__fxstatat\0__lxstat\0__xstat\0";
 361         size_t l;
 362         char buf[16];
 363         for (l=0; name[l]; l++) {
 364                 if (l >= sizeof buf) goto nomatch;
 365                 buf[l] = name[l];
 366         }
 367         if (!strcmp(name, "readdir64_r"))
 368                 return find_sym(&ldso, "readdir_r", 1);
 369         if (l<2 || name[l-2]!='6' || name[l-1]!='4')
 370                 goto nomatch;
 371         buf[l-=2] = 0;
 372         for (p=lfs64_list; *p; p++) {
 373                 if (!strcmp(buf, p)) return find_sym(&ldso, buf, 1);
 374                 while (*p) p++;
 375         }
 376 nomatch:
 377         return (struct symdef){ 0 };
 378 }
 379
 380 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 381 {
 382         unsigned char *base = dso->base;
 383         Sym *syms = dso->syms;
 384         char *strings = dso->strings;
 385         Sym *sym;
 386         const char *name;
 387         void *ctx;
 388         int type;
 389         int sym_index;
 390         struct symdef def;
 391         size_t *reloc_addr;
 392         size_t sym_val;
 393         size_t tls_val;
 394         size_t addend;
 395         int skip_relative = 0, reuse_addends = 0, save_slot = 0;
 396
 397         if (dso == &ldso) {
 398                 /* Only ldso's REL table needs addend saving/reuse. */
 399                 if (rel == apply_addends_to)
 400                         reuse_addends = 1;
 401                 skip_relative = 1;
 402         }
 403
 404         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 405                 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
 406                 type = R_TYPE(rel[1]);
 407                 if (type == REL_NONE) continue;
 408                 reloc_addr = laddr(dso, rel[0]);
 409
 410                 if (stride > 2) {
 411                         addend = rel[2];
 412                 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
 413                         addend = 0;
 414                 } else if (reuse_addends) {
 415                         /* Save original addend in stage 2 where the dso
 416                          * chain consists of just ldso; otherwise read back
 417                          * saved addend since the inline one was clobbered. */
 418                         if (head==&ldso)
 419                                 saved_addends[save_slot] = *reloc_addr;
 420                         addend = saved_addends[save_slot++];
 421                 } else {
 422                         addend = *reloc_addr;
 423                 }
 424
 425                 sym_index = R_SYM(rel[1]);
 426                 if (sym_index) {
 427                         sym = syms + sym_index;
 428                         name = strings + sym->st_name;
 429                         ctx = type==REL_COPY ? head->syms_next : head;
 430                         def = (sym->st_info>>4) == STB_LOCAL
 431                                 ? (struct symdef){ .dso = dso, .sym = sym }
 432                                 : find_sym(ctx, name, type==REL_PLT);
 433                         if (!def.sym) def = get_lfs64(name);
 434                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 435                             || sym->st_info>>4 != STB_WEAK)) {
 436                                 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
 437                                         dso->lazy[3*dso->lazy_cnt+0] = rel[0];
 438                                         dso->lazy[3*dso->lazy_cnt+1] = rel[1];
 439                                         dso->lazy[3*dso->lazy_cnt+2] = addend;
 440                                         dso->lazy_cnt++;
 441                                         continue;
 442                                 }
 443                                 error("Error relocating %s: %s: symbol not found",
 444                                         dso->name, name);
 445                                 if (runtime) longjmp(*rtld_fail, 1);
 446                                 continue;
 447                         }
 448                 } else {
 449                         sym = 0;
 450                         def.sym = 0;
 451                         def.dso = dso;
 452                 }
 453
 454                 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
 455                 tls_val = def.sym ? def.sym->st_value : 0;
 456
 457                 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
 458                     && def.dso->tls_id > static_tls_cnt) {
 459                         error("Error relocating %s: %s: initial-exec TLS "
 460                                 "resolves to dynamic definition in %s",
 461                                 dso->name, name, def.dso->name);
 462                         longjmp(*rtld_fail, 1);
 463                 }
 464
 465                 switch(type) {
 466                 case REL_OFFSET:
 467                         addend -= (size_t)reloc_addr;
 468                 case REL_SYMBOLIC:
 469                 case REL_GOT:
 470                 case REL_PLT:
 471                         *reloc_addr = sym_val + addend;
 472                         break;
 473                 case REL_USYMBOLIC:
 474                         memcpy(reloc_addr, &(size_t){sym_val + addend}, sizeof(size_t));
 475                         break;
 476                 case REL_RELATIVE:
 477                         *reloc_addr = (size_t)base + addend;
 478                         break;
 479                 case REL_SYM_OR_REL:
 480                         if (sym) *reloc_addr = sym_val + addend;
 481                         else *reloc_addr = (size_t)base + addend;
 482                         break;
 483                 case REL_COPY:
 484                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 485                         break;
 486                 case REL_OFFSET32:
 487                         *(uint32_t *)reloc_addr = sym_val + addend
 488                                 - (size_t)reloc_addr;
 489                         break;
 490                 case REL_FUNCDESC:
 491                         *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
 492                                 + (def.sym - def.dso->syms)) : 0;
 493                         break;
 494                 case REL_FUNCDESC_VAL:
 495                         if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
 496                         else *reloc_addr = sym_val;
 497                         reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
 498                         break;
 499                 case REL_DTPMOD:
 500                         *reloc_addr = def.dso->tls_id;
 501                         break;
 502                 case REL_DTPOFF:
 503                         *reloc_addr = tls_val + addend - DTP_OFFSET;
 504                         break;
 505 #ifdef TLS_ABOVE_TP
 506                 case REL_TPOFF:
 507                         *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
 508                         break;
 509 #else
 510                 case REL_TPOFF:
 511                         *reloc_addr = tls_val - def.dso->tls.offset + addend;
 512                         break;
 513                 case REL_TPOFF_NEG:
 514                         *reloc_addr = def.dso->tls.offset - tls_val + addend;
 515                         break;
 516 #endif
 517                 case REL_TLSDESC:
 518                         if (stride<3) addend = reloc_addr[1];
 519                         if (def.dso->tls_id > static_tls_cnt) {
 520                                 struct td_index *new = malloc(sizeof *new);
 521                                 if (!new) {
 522                                         error(
 523                                         "Error relocating %s: cannot allocate TLSDESC for %s",
 524                                         dso->name, sym ? name : "(local)" );
 525                                         longjmp(*rtld_fail, 1);
 526                                 }
 527                                 new->next = dso->td_index;
 528                                 dso->td_index = new;
 529                                 new->args[0] = def.dso->tls_id;
 530                                 new->args[1] = tls_val + addend - DTP_OFFSET;
 531                                 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
 532                                 reloc_addr[1] = (size_t)new;
 533                         } else {
 534                                 reloc_addr[0] = (size_t)__tlsdesc_static;
 535 #ifdef TLS_ABOVE_TP
 536                                 reloc_addr[1] = tls_val + def.dso->tls.offset
 537                                         + TPOFF_K + addend;
 538 #else
 539                                 reloc_addr[1] = tls_val - def.dso->tls.offset
 540                                         + addend;
 541 #endif
 542                         }
 543 #ifdef TLSDESC_BACKWARDS
 544                         /* Some archs (32-bit ARM at least) invert the order of
 545                          * the descriptor members. Fix them up here. */
 546                         size_t tmp = reloc_addr[0];
 547                         reloc_addr[0] = reloc_addr[1];
 548                         reloc_addr[1] = tmp;
 549 #endif
 550                         break;
 551                 default:
 552                         error("Error relocating %s: unsupported relocation type %d",
 553                                 dso->name, type);
 554                         if (runtime) longjmp(*rtld_fail, 1);
 555                         continue;
 556                 }
 557         }
 558 }
 559
 560 static void do_relr_relocs(struct dso *dso, size_t *relr, size_t relr_size)
 561 {
 562         if (dso == &ldso) return; /* self-relocation was done in _dlstart */
 563         unsigned char *base = dso->base;
 564         size_t *reloc_addr;
 565         for (; relr_size; relr++, relr_size-=sizeof(size_t))
 566                 if ((relr[0]&1) == 0) {
 567                         reloc_addr = laddr(dso, relr[0]);
 568                         *reloc_addr++ += (size_t)base;
 569                 } else {
 570                         int i = 0;
 571                         for (size_t bitmap=relr[0]; (bitmap>>=1); i++)
 572                                 if (bitmap&1)
 573                                         reloc_addr[i] += (size_t)base;
 574                         reloc_addr += 8*sizeof(size_t)-1;
 575                 }
 576 }
 577
 578 static void redo_lazy_relocs()
 579 {
 580         struct dso *p = lazy_head, *next;
 581         lazy_head = 0;
 582         for (; p; p=next) {
 583                 next = p->lazy_next;
 584                 size_t size = p->lazy_cnt*3*sizeof(size_t);
 585                 p->lazy_cnt = 0;
 586                 do_relocs(p, p->lazy, size, 3);
 587                 if (p->lazy_cnt) {
 588                         p->lazy_next = lazy_head;
 589                         lazy_head = p;
 590                 } else {
 591                         free(p->lazy);
 592                         p->lazy = 0;
 593                         p->lazy_next = 0;
 594                 }
 595         }
 596 }
 597
 598 /* A huge hack: to make up for the wastefulness of shared libraries
 599  * needing at least a page of dirty memory even if they have no global
 600  * data, we reclaim the gaps at the beginning and end of writable maps
 601  * and "donate" them to the heap. */
 602
 603 static void reclaim(struct dso *dso, size_t start, size_t end)
 604 {
 605         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 606         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 607         if (start >= end) return;
 608         char *base = laddr_pg(dso, start);
 609         __malloc_donate(base, base+(end-start));
 610 }
 611
 612 static void reclaim_gaps(struct dso *dso)
 613 {
 614         Phdr *ph = dso->phdr;
 615         size_t phcnt = dso->phnum;
 616
 617         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 618                 if (ph->p_type!=PT_LOAD) continue;
 619                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 620                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 621                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 622                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 623         }
 624 }
 625
 626 static ssize_t read_loop(int fd, void *p, size_t n)
 627 {
 628         for (size_t i=0; i<n; ) {
 629                 ssize_t l = read(fd, (char *)p+i, n-i);
 630                 if (l<0) {
 631                         if (errno==EINTR) continue;
 632                         else return -1;
 633                 }
 634                 if (l==0) return i;
 635                 i += l;
 636         }
 637         return n;
 638 }
 639
 640 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
 641 {
 642         static int no_map_fixed;
 643         char *q;
 644         if (!n) return p;
 645         if (!no_map_fixed) {
 646                 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
 647                 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
 648                         return q;
 649                 no_map_fixed = 1;
 650         }
 651         /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
 652         if (flags & MAP_ANONYMOUS) {
 653                 memset(p, 0, n);
 654                 return p;
 655         }
 656         ssize_t r;
 657         if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
 658         for (q=p; n; q+=r, off+=r, n-=r) {
 659                 r = read(fd, q, n);
 660                 if (r < 0 && errno != EINTR) return MAP_FAILED;
 661                 if (!r) {
 662                         memset(q, 0, n);
 663                         break;
 664                 }
 665         }
 666         return p;
 667 }
 668
 669 static void unmap_library(struct dso *dso)
 670 {
 671         if (dso->loadmap) {
 672                 size_t i;
 673                 for (i=0; i<dso->loadmap->nsegs; i++) {
 674                         if (!dso->loadmap->segs[i].p_memsz)
 675                                 continue;
 676                         munmap((void *)dso->loadmap->segs[i].addr,
 677                                 dso->loadmap->segs[i].p_memsz);
 678                 }
 679                 free(dso->loadmap);
 680         } else if (dso->map && dso->map_len) {
 681                 munmap(dso->map, dso->map_len);
 682         }
 683 }
 684
 685 static void *map_library(int fd, struct dso *dso)
 686 {
 687         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 688         void *allocated_buf=0;
 689         size_t phsize;
 690         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 691         size_t this_min, this_max;
 692         size_t nsegs = 0;
 693         off_t off_start;
 694         Ehdr *eh;
 695         Phdr *ph, *ph0;
 696         unsigned prot;
 697         unsigned char *map=MAP_FAILED, *base;
 698         size_t dyn=0;
 699         size_t tls_image=0;
 700         size_t i;
 701
 702         ssize_t l = read(fd, buf, sizeof buf);
 703         eh = buf;
 704         if (l<0) return 0;
 705         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 706                 goto noexec;
 707         phsize = eh->e_phentsize * eh->e_phnum;
 708         if (phsize > sizeof buf - sizeof *eh) {
 709                 allocated_buf = malloc(phsize);
 710                 if (!allocated_buf) return 0;
 711                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 712                 if (l < 0) goto error;
 713                 if (l != phsize) goto noexec;
 714                 ph = ph0 = allocated_buf;
 715         } else if (eh->e_phoff + phsize > l) {
 716                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 717                 if (l < 0) goto error;
 718                 if (l != phsize) goto noexec;
 719                 ph = ph0 = (void *)(buf + 1);
 720         } else {
 721                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 722         }
 723         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 724                 if (ph->p_type == PT_DYNAMIC) {
 725                         dyn = ph->p_vaddr;
 726                 } else if (ph->p_type == PT_TLS) {
 727                         tls_image = ph->p_vaddr;
 728                         dso->tls.align = ph->p_align;
 729                         dso->tls.len = ph->p_filesz;
 730                         dso->tls.size = ph->p_memsz;
 731                 } else if (ph->p_type == PT_GNU_RELRO) {
 732                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 733                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 734                 } else if (ph->p_type == PT_GNU_STACK) {
 735                         if (!runtime && ph->p_memsz > __default_stacksize) {
 736                                 __default_stacksize =
 737                                         ph->p_memsz < DEFAULT_STACK_MAX ?
 738                                         ph->p_memsz : DEFAULT_STACK_MAX;
 739                         }
 740                 }
 741                 if (ph->p_type != PT_LOAD) continue;
 742                 nsegs++;
 743                 if (ph->p_vaddr < addr_min) {
 744                         addr_min = ph->p_vaddr;
 745                         off_start = ph->p_offset;
 746                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 747                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 748                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 749                 }
 750                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 751                         addr_max = ph->p_vaddr+ph->p_memsz;
 752                 }
 753         }
 754         if (!dyn) goto noexec;
 755         if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
 756                 dso->loadmap = calloc(1, sizeof *dso->loadmap
 757                         + nsegs * sizeof *dso->loadmap->segs);
 758                 if (!dso->loadmap) goto error;
 759                 dso->loadmap->nsegs = nsegs;
 760                 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
 761                         if (ph->p_type != PT_LOAD) continue;
 762                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 763                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 764                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 765                         map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
 766                                 prot, MAP_PRIVATE,
 767                                 fd, ph->p_offset & -PAGE_SIZE);
 768                         if (map == MAP_FAILED) {
 769                                 unmap_library(dso);
 770                                 goto error;
 771                         }
 772                         dso->loadmap->segs[i].addr = (size_t)map +
 773                                 (ph->p_vaddr & PAGE_SIZE-1);
 774                         dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
 775                         dso->loadmap->segs[i].p_memsz = ph->p_memsz;
 776                         i++;
 777                         if (prot & PROT_WRITE) {
 778                                 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
 779                                         + ph->p_filesz;
 780                                 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
 781                                 size_t pgend = brk + ph->p_memsz - ph->p_filesz
 782                                         + PAGE_SIZE-1 & -PAGE_SIZE;
 783                                 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
 784                                         pgend-pgbrk, prot,
 785                                         MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
 786                                         -1, off_start) == MAP_FAILED)
 787                                         goto error;
 788                                 memset(map + brk, 0, pgbrk-brk);
 789                         }
 790                 }
 791                 map = (void *)dso->loadmap->segs[0].addr;
 792                 map_len = 0;
 793                 goto done_mapping;
 794         }
 795         addr_max += PAGE_SIZE-1;
 796         addr_max &= -PAGE_SIZE;
 797         addr_min &= -PAGE_SIZE;
 798         off_start &= -PAGE_SIZE;
 799         map_len = addr_max - addr_min + off_start;
 800         /* The first time, we map too much, possibly even more than
 801          * the length of the file. This is okay because we will not
 802          * use the invalid part; we just need to reserve the right
 803          * amount of virtual address space to map over later. */
 804         map = DL_NOMMU_SUPPORT
 805                 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
 806                         MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
 807                 : mmap((void *)addr_min, map_len, prot,
 808                         MAP_PRIVATE, fd, off_start);
 809         if (map==MAP_FAILED) goto error;
 810         dso->map = map;
 811         dso->map_len = map_len;
 812         /* If the loaded file is not relocatable and the requested address is
 813          * not available, then the load operation must fail. */
 814         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 815                 errno = EBUSY;
 816                 goto error;
 817         }
 818         base = map - addr_min;
 819         dso->phdr = 0;
 820         dso->phnum = 0;
 821         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 822                 if (ph->p_type != PT_LOAD) continue;
 823                 /* Check if the programs headers are in this load segment, and
 824                  * if so, record the address for use by dl_iterate_phdr. */
 825                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 826                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 827                         dso->phdr = (void *)(base + ph->p_vaddr
 828                                 + (eh->e_phoff-ph->p_offset));
 829                         dso->phnum = eh->e_phnum;
 830                         dso->phentsize = eh->e_phentsize;
 831                 }
 832                 this_min = ph->p_vaddr & -PAGE_SIZE;
 833                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 834                 off_start = ph->p_offset & -PAGE_SIZE;
 835                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 836                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 837                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 838                 /* Reuse the existing mapping for the lowest-address LOAD */
 839                 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
 840                         if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 841                                 goto error;
 842                 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
 843                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 844                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 845                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 846                         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)
 847                                 goto error;
 848                 }
 849         }
 850         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 851                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 852                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
 853                             && errno != ENOSYS)
 854                                 goto error;
 855                         break;
 856                 }
 857 done_mapping:
 858         dso->base = base;
 859         dso->dynv = laddr(dso, dyn);
 860         if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
 861         free(allocated_buf);
 862         return map;
 863 noexec:
 864         errno = ENOEXEC;
 865 error:
 866         if (map!=MAP_FAILED) unmap_library(dso);
 867         free(allocated_buf);
 868         return 0;
 869 }
 870
 871 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 872 {
 873         size_t l;
 874         int fd;
 875         for (;;) {
 876                 s += strspn(s, ":\n");
 877                 l = strcspn(s, ":\n");
 878                 if (l-1 >= INT_MAX) return -1;
 879                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
 880                         if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 881                         switch (errno) {
 882                         case ENOENT:
 883                         case ENOTDIR:
 884                         case EACCES:
 885                         case ENAMETOOLONG:
 886                                 break;
 887                         default:
 888                                 /* Any negative value but -1 will inhibit
 889                                  * futher path search. */
 890                                 return -2;
 891                         }
 892                 }
 893                 s += l;
 894         }
 895 }
 896
 897 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 898 {
 899         size_t n, l;
 900         const char *s, *t, *origin;
 901         char *d;
 902         if (p->rpath || !p->rpath_orig) return 0;
 903         if (!strchr(p->rpath_orig, '$')) {
 904                 p->rpath = p->rpath_orig;
 905                 return 0;
 906         }
 907         n = 0;
 908         s = p->rpath_orig;
 909         while ((t=strchr(s, '$'))) {
 910                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 911                         return 0;
 912                 s = t+1;
 913                 n++;
 914         }
 915         if (n > SSIZE_MAX/PATH_MAX) return 0;
 916
 917         if (p->kernel_mapped) {
 918                 /* $ORIGIN searches cannot be performed for the main program
 919                  * when it is suid/sgid/AT_SECURE. This is because the
 920                  * pathname is under the control of the caller of execve.
 921                  * For libraries, however, $ORIGIN can be processed safely
 922                  * since the library's pathname came from a trusted source
 923                  * (either system paths or a call to dlopen). */
 924                 if (libc.secure)
 925                         return 0;
 926                 l = readlink("/proc/self/exe", buf, buf_size);
 927                 if (l == -1) switch (errno) {
 928                 case ENOENT:
 929                 case ENOTDIR:
 930                 case EACCES:
 931                         return 0;
 932                 default:
 933                         return -1;
 934                 }
 935                 if (l >= buf_size)
 936                         return 0;
 937                 buf[l] = 0;
 938                 origin = buf;
 939         } else {
 940                 origin = p->name;
 941         }
 942         t = strrchr(origin, '/');
 943         if (t) {
 944                 l = t-origin;
 945         } else {
 946                 /* Normally p->name will always be an absolute or relative
 947                  * pathname containing at least one '/' character, but in the
 948                  * case where ldso was invoked as a command to execute a
 949                  * program in the working directory, app.name may not. Fix. */
 950                 origin = ".";
 951                 l = 1;
 952         }
 953         /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
 954         if (libc.secure && *origin != '/')
 955                 return 0;
 956         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 957         if (!p->rpath) return -1;
 958
 959         d = p->rpath;
 960         s = p->rpath_orig;
 961         while ((t=strchr(s, '$'))) {
 962                 memcpy(d, s, t-s);
 963                 d += t-s;
 964                 memcpy(d, origin, l);
 965                 d += l;
 966                 /* It was determined previously that the '$' is followed
 967                  * either by "ORIGIN" or "{ORIGIN}". */
 968                 s = t + 7 + 2*(t[1]=='{');
 969         }
 970         strcpy(d, s);
 971         return 0;
 972 }
 973
 974 static void decode_dyn(struct dso *p)
 975 {
 976         size_t dyn[DYN_CNT];
 977         decode_vec(p->dynv, dyn, DYN_CNT);
 978         p->syms = laddr(p, dyn[DT_SYMTAB]);
 979         p->strings = laddr(p, dyn[DT_STRTAB]);
 980         if (dyn[0]&(1<<DT_HASH))
 981                 p->hashtab = laddr(p, dyn[DT_HASH]);
 982         if (dyn[0]&(1<<DT_RPATH))
 983                 p->rpath_orig = p->strings + dyn[DT_RPATH];
 984         if (dyn[0]&(1<<DT_RUNPATH))
 985                 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
 986         if (dyn[0]&(1<<DT_PLTGOT))
 987                 p->got = laddr(p, dyn[DT_PLTGOT]);
 988         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 989                 p->ghashtab = laddr(p, *dyn);
 990         if (search_vec(p->dynv, dyn, DT_VERSYM))
 991                 p->versym = laddr(p, *dyn);
 992 }
 993
 994 static size_t count_syms(struct dso *p)
 995 {
 996         if (p->hashtab) return p->hashtab[1];
 997
 998         size_t nsym, i;
 999         uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1000         uint32_t *hashval;
1001         for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1002                 if (buckets[i] > nsym)
1003                         nsym = buckets[i];
1004         }
1005         if (nsym) {
1006                 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
1007                 do nsym++;
1008                 while (!(*hashval++ & 1));
1009         }
1010         return nsym;
1011 }
1012
1013 static void *dl_mmap(size_t n)
1014 {
1015         void *p;
1016         int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
1017 #ifdef SYS_mmap2
1018         p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
1019 #else
1020         p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
1021 #endif
1022         return (unsigned long)p > -4096UL ? 0 : p;
1023 }
1024
1025 static void makefuncdescs(struct dso *p)
1026 {
1027         static int self_done;
1028         size_t nsym = count_syms(p);
1029         size_t i, size = nsym * sizeof(*p->funcdescs);
1030
1031         if (!self_done) {
1032                 p->funcdescs = dl_mmap(size);
1033                 self_done = 1;
1034         } else {
1035                 p->funcdescs = malloc(size);
1036         }
1037         if (!p->funcdescs) {
1038                 if (!runtime) a_crash();
1039                 error("Error allocating function descriptors for %s", p->name);
1040                 longjmp(*rtld_fail, 1);
1041         }
1042         for (i=0; i<nsym; i++) {
1043                 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
1044                         p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
1045                         p->funcdescs[i].got = p->got;
1046                 } else {
1047                         p->funcdescs[i].addr = 0;
1048                         p->funcdescs[i].got = 0;
1049                 }
1050         }
1051 }
1052
1053 static struct dso *load_library(const char *name, struct dso *needed_by)
1054 {
1055         char buf[2*NAME_MAX+2];
1056         const char *pathname;
1057         unsigned char *map;
1058         struct dso *p, temp_dso = {0};
1059         int fd;
1060         struct stat st;
1061         size_t alloc_size;
1062         int n_th = 0;
1063         int is_self = 0;
1064
1065         if (!*name) {
1066                 errno = EINVAL;
1067                 return 0;
1068         }
1069
1070         /* Catch and block attempts to reload the implementation itself */
1071         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
1072                 static const char reserved[] =
1073                         "c.pthread.rt.m.dl.util.xnet.";
1074                 const char *rp, *next;
1075                 for (rp=reserved; *rp; rp=next) {
1076                         next = strchr(rp, '.') + 1;
1077                         if (strncmp(name+3, rp, next-rp) == 0)
1078                                 break;
1079                 }
1080                 if (*rp) {
1081                         if (ldd_mode) {
1082                                 /* Track which names have been resolved
1083                                  * and only report each one once. */
1084                                 static unsigned reported;
1085                                 unsigned mask = 1U<<(rp-reserved);
1086                                 if (!(reported & mask)) {
1087                                         reported |= mask;
1088                                         dprintf(1, "\t%s => %s (%p)\n",
1089                                                 name, ldso.name,
1090                                                 ldso.base);
1091                                 }
1092                         }
1093                         is_self = 1;
1094                 }
1095         }
1096         if (!strcmp(name, ldso.name)) is_self = 1;
1097         if (is_self) {
1098                 if (!ldso.prev) {
1099                         tail->next = &ldso;
1100                         ldso.prev = tail;
1101                         tail = &ldso;
1102                 }
1103                 return &ldso;
1104         }
1105         if (strchr(name, '/')) {
1106                 pathname = name;
1107                 fd = open(name, O_RDONLY|O_CLOEXEC);
1108         } else {
1109                 /* Search for the name to see if it's already loaded */
1110                 for (p=head->next; p; p=p->next) {
1111                         if (p->shortname && !strcmp(p->shortname, name)) {
1112                                 return p;
1113                         }
1114                 }
1115                 if (strlen(name) > NAME_MAX) return 0;
1116                 fd = -1;
1117                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1118                 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1119                         if (fixup_rpath(p, buf, sizeof buf) < 0)
1120                                 fd = -2; /* Inhibit further search. */
1121                         if (p->rpath)
1122                                 fd = path_open(name, p->rpath, buf, sizeof buf);
1123                 }
1124                 if (fd == -1) {
1125                         if (!sys_path) {
1126                                 char *prefix = 0;
1127                                 size_t prefix_len;
1128                                 if (ldso.name[0]=='/') {
1129                                         char *s, *t, *z;
1130                                         for (s=t=z=ldso.name; *s; s++)
1131                                                 if (*s=='/') z=t, t=s;
1132                                         prefix_len = z-ldso.name;
1133                                         if (prefix_len < PATH_MAX)
1134                                                 prefix = ldso.name;
1135                                 }
1136                                 if (!prefix) {
1137                                         prefix = "";
1138                                         prefix_len = 0;
1139                                 }
1140                                 char etc_ldso_path[prefix_len + 1
1141                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1142                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1143                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1144                                         (int)prefix_len, prefix);
1145                                 fd = open(etc_ldso_path, O_RDONLY|O_CLOEXEC);
1146                                 if (fd>=0) {
1147                                         size_t n = 0;
1148                                         if (!fstat(fd, &st)) n = st.st_size;
1149                                         if ((sys_path = malloc(n+1)))
1150                                                 sys_path[n] = 0;
1151                                         if (!sys_path || read_loop(fd, sys_path, n)<0) {
1152                                                 free(sys_path);
1153                                                 sys_path = "";
1154                                         }
1155                                         close(fd);
1156                                 } else if (errno != ENOENT) {
1157                                         sys_path = "";
1158                                 }
1159                         }
1160                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1161                         fd = path_open(name, sys_path, buf, sizeof buf);
1162                 }
1163                 pathname = buf;
1164         }
1165         if (fd < 0) return 0;
1166         if (fstat(fd, &st) < 0) {
1167                 close(fd);
1168                 return 0;
1169         }
1170         for (p=head->next; p; p=p->next) {
1171                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1172                         /* If this library was previously loaded with a
1173                          * pathname but a search found the same inode,
1174                          * setup its shortname so it can be found by name. */
1175                         if (!p->shortname && pathname != name)
1176                                 p->shortname = strrchr(p->name, '/')+1;
1177                         close(fd);
1178                         return p;
1179                 }
1180         }
1181         map = noload ? 0 : map_library(fd, &temp_dso);
1182         close(fd);
1183         if (!map) return 0;
1184
1185         /* Avoid the danger of getting two versions of libc mapped into the
1186          * same process when an absolute pathname was used. The symbols
1187          * checked are chosen to catch both musl and glibc, and to avoid
1188          * false positives from interposition-hack libraries. */
1189         decode_dyn(&temp_dso);
1190         if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1191             find_sym(&temp_dso, "stdin", 1).sym) {
1192                 unmap_library(&temp_dso);
1193                 return load_library("libc.so", needed_by);
1194         }
1195         /* Past this point, if we haven't reached runtime yet, ldso has
1196          * committed either to use the mapped library or to abort execution.
1197          * Unmapping is not possible, so we can safely reclaim gaps. */
1198         if (!runtime) reclaim_gaps(&temp_dso);
1199
1200         /* Allocate storage for the new DSO. When there is TLS, this
1201          * storage must include a reservation for all pre-existing
1202          * threads to obtain copies of both the new TLS, and an
1203          * extended DTV capable of storing an additional slot for
1204          * the newly-loaded DSO. */
1205         alloc_size = sizeof *p + strlen(pathname) + 1;
1206         if (runtime && temp_dso.tls.image) {
1207                 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1208                         + sizeof(void *) * (tls_cnt+3);
1209                 n_th = libc.threads_minus_1 + 1;
1210                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1211                 else alloc_size += n_th * per_th;
1212         }
1213         p = calloc(1, alloc_size);
1214         if (!p) {
1215                 unmap_library(&temp_dso);
1216                 return 0;
1217         }
1218         memcpy(p, &temp_dso, sizeof temp_dso);
1219         p->dev = st.st_dev;
1220         p->ino = st.st_ino;
1221         p->needed_by = needed_by;
1222         p->name = p->buf;
1223         p->runtime_loaded = runtime;
1224         strcpy(p->name, pathname);
1225         /* Add a shortname only if name arg was not an explicit pathname. */
1226         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1227         if (p->tls.image) {
1228                 p->tls_id = ++tls_cnt;
1229                 tls_align = MAXP2(tls_align, p->tls.align);
1230 #ifdef TLS_ABOVE_TP
1231                 p->tls.offset = tls_offset + ( (p->tls.align-1) &
1232                         (-tls_offset + (uintptr_t)p->tls.image) );
1233                 tls_offset = p->tls.offset + p->tls.size;
1234 #else
1235                 tls_offset += p->tls.size + p->tls.align - 1;
1236                 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1237                         & (p->tls.align-1);
1238                 p->tls.offset = tls_offset;
1239 #endif
1240                 p->new_dtv = (void *)(-sizeof(size_t) &
1241                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1242                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1243                 if (tls_tail) tls_tail->next = &p->tls;
1244                 else libc.tls_head = &p->tls;
1245                 tls_tail = &p->tls;
1246         }
1247
1248         tail->next = p;
1249         p->prev = tail;
1250         tail = p;
1251
1252         if (DL_FDPIC) makefuncdescs(p);
1253
1254         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1255
1256         return p;
1257 }
1258
1259 static void load_direct_deps(struct dso *p)
1260 {
1261         size_t i, cnt=0;
1262
1263         if (p->deps) return;
1264         /* For head, all preloads are direct pseudo-dependencies.
1265          * Count and include them now to avoid realloc later. */
1266         if (p==head) for (struct dso *q=p->next; q; q=q->next)
1267                 cnt++;
1268         for (i=0; p->dynv[i]; i+=2)
1269                 if (p->dynv[i] == DT_NEEDED) cnt++;
1270         /* Use builtin buffer for apps with no external deps, to
1271          * preserve property of no runtime failure paths. */
1272         p->deps = (p==head && cnt<2) ? builtin_deps :
1273                 calloc(cnt+1, sizeof *p->deps);
1274         if (!p->deps) {
1275                 error("Error loading dependencies for %s", p->name);
1276                 if (runtime) longjmp(*rtld_fail, 1);
1277         }
1278         cnt=0;
1279         if (p==head) for (struct dso *q=p->next; q; q=q->next)
1280                 p->deps[cnt++] = q;
1281         for (i=0; p->dynv[i]; i+=2) {
1282                 if (p->dynv[i] != DT_NEEDED) continue;
1283                 struct dso *dep = load_library(p->strings + p->dynv[i+1], p);
1284                 if (!dep) {
1285                         error("Error loading shared library %s: %m (needed by %s)",
1286                                 p->strings + p->dynv[i+1], p->name);
1287                         if (runtime) longjmp(*rtld_fail, 1);
1288                         continue;
1289                 }
1290                 p->deps[cnt++] = dep;
1291         }
1292         p->deps[cnt] = 0;
1293         p->ndeps_direct = cnt;
1294 }
1295
1296 static void load_deps(struct dso *p)
1297 {
1298         if (p->deps) return;
1299         for (; p; p=p->next)
1300                 load_direct_deps(p);
1301 }
1302
1303 static void extend_bfs_deps(struct dso *p)
1304 {
1305         size_t i, j, cnt, ndeps_all;
1306         struct dso **tmp;
1307
1308         /* Can't use realloc if the original p->deps was allocated at
1309          * program entry and malloc has been replaced, or if it's
1310          * the builtin non-allocated trivial main program deps array. */
1311         int no_realloc = (__malloc_replaced && !p->runtime_loaded)
1312                 || p->deps == builtin_deps;
1313
1314         if (p->bfs_built) return;
1315         ndeps_all = p->ndeps_direct;
1316
1317         /* Mark existing (direct) deps so they won't be duplicated. */
1318         for (i=0; p->deps[i]; i++)
1319                 p->deps[i]->mark = 1;
1320
1321         /* For each dependency already in the list, copy its list of direct
1322          * dependencies to the list, excluding any items already in the
1323          * list. Note that the list this loop iterates over will grow during
1324          * the loop, but since duplicates are excluded, growth is bounded. */
1325         for (i=0; p->deps[i]; i++) {
1326                 struct dso *dep = p->deps[i];
1327                 for (j=cnt=0; j<dep->ndeps_direct; j++)
1328                         if (!dep->deps[j]->mark) cnt++;
1329                 tmp = no_realloc ?
1330                         malloc(sizeof(*tmp) * (ndeps_all+cnt+1)) :
1331                         realloc(p->deps, sizeof(*tmp) * (ndeps_all+cnt+1));
1332                 if (!tmp) {
1333                         error("Error recording dependencies for %s", p->name);
1334                         if (runtime) longjmp(*rtld_fail, 1);
1335                         continue;
1336                 }
1337                 if (no_realloc) {
1338                         memcpy(tmp, p->deps, sizeof(*tmp) * (ndeps_all+1));
1339                         no_realloc = 0;
1340                 }
1341                 p->deps = tmp;
1342                 for (j=0; j<dep->ndeps_direct; j++) {
1343                         if (dep->deps[j]->mark) continue;
1344                         dep->deps[j]->mark = 1;
1345                         p->deps[ndeps_all++] = dep->deps[j];
1346                 }
1347                 p->deps[ndeps_all] = 0;
1348         }
1349         p->bfs_built = 1;
1350         for (p=head; p; p=p->next)
1351                 p->mark = 0;
1352 }
1353
1354 static void load_preload(char *s)
1355 {
1356         int tmp;
1357         char *z;
1358         for (z=s; *z; s=z) {
1359                 for (   ; *s && (isspace(*s) || *s==':'); s++);
1360                 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1361                 tmp = *z;
1362                 *z = 0;
1363                 load_library(s, 0);
1364                 *z = tmp;
1365         }
1366 }
1367
1368 static void add_syms(struct dso *p)
1369 {
1370         if (!p->syms_next && syms_tail != p) {
1371                 syms_tail->syms_next = p;
1372                 syms_tail = p;
1373         }
1374 }
1375
1376 static void revert_syms(struct dso *old_tail)
1377 {
1378         struct dso *p, *next;
1379         /* Chop off the tail of the list of dsos that participate in
1380          * the global symbol table, reverting them to RTLD_LOCAL. */
1381         for (p=old_tail; p; p=next) {
1382                 next = p->syms_next;
1383                 p->syms_next = 0;
1384         }
1385         syms_tail = old_tail;
1386 }
1387
1388 static void do_mips_relocs(struct dso *p, size_t *got)
1389 {
1390         size_t i, j, rel[2];
1391         unsigned char *base = p->base;
1392         i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1393         if (p==&ldso) {
1394                 got += i;
1395         } else {
1396                 while (i--) *got++ += (size_t)base;
1397         }
1398         j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1399         i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1400         Sym *sym = p->syms + j;
1401         rel[0] = (unsigned char *)got - base;
1402         for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1403                 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1404                 do_relocs(p, rel, sizeof rel, 2);
1405         }
1406 }
1407
1408 static void reloc_all(struct dso *p)
1409 {
1410         size_t dyn[DYN_CNT];
1411         for (; p; p=p->next) {
1412                 if (p->relocated) continue;
1413                 decode_vec(p->dynv, dyn, DYN_CNT);
1414                 if (NEED_MIPS_GOT_RELOCS)
1415                         do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1416                 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1417                         2+(dyn[DT_PLTREL]==DT_RELA));
1418                 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1419                 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1420                 if (!DL_FDPIC)
1421                         do_relr_relocs(p, laddr(p, dyn[DT_RELR]), dyn[DT_RELRSZ]);
1422
1423                 if (head != &ldso && p->relro_start != p->relro_end) {
1424                         long ret = __syscall(SYS_mprotect, laddr(p, p->relro_start),
1425                                 p->relro_end-p->relro_start, PROT_READ);
1426                         if (ret != 0 && ret != -ENOSYS) {
1427                                 error("Error relocating %s: RELRO protection failed: %m",
1428                                         p->name);
1429                                 if (runtime) longjmp(*rtld_fail, 1);
1430                         }
1431                 }
1432
1433                 p->relocated = 1;
1434         }
1435 }
1436
1437 static void kernel_mapped_dso(struct dso *p)
1438 {
1439         size_t min_addr = -1, max_addr = 0, cnt;
1440         Phdr *ph = p->phdr;
1441         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1442                 if (ph->p_type == PT_DYNAMIC) {
1443                         p->dynv = laddr(p, ph->p_vaddr);
1444                 } else if (ph->p_type == PT_GNU_RELRO) {
1445                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1446                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1447                 } else if (ph->p_type == PT_GNU_STACK) {
1448                         if (!runtime && ph->p_memsz > __default_stacksize) {
1449                                 __default_stacksize =
1450                                         ph->p_memsz < DEFAULT_STACK_MAX ?
1451                                         ph->p_memsz : DEFAULT_STACK_MAX;
1452                         }
1453                 }
1454                 if (ph->p_type != PT_LOAD) continue;
1455                 if (ph->p_vaddr < min_addr)
1456                         min_addr = ph->p_vaddr;
1457                 if (ph->p_vaddr+ph->p_memsz > max_addr)
1458                         max_addr = ph->p_vaddr+ph->p_memsz;
1459         }
1460         min_addr &= -PAGE_SIZE;
1461         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1462         p->map = p->base + min_addr;
1463         p->map_len = max_addr - min_addr;
1464         p->kernel_mapped = 1;
1465 }
1466
1467 void __libc_exit_fini()
1468 {
1469         struct dso *p;
1470         size_t dyn[DYN_CNT];
1471         pthread_t self = __pthread_self();
1472
1473         /* Take both locks before setting shutting_down, so that
1474          * either lock is sufficient to read its value. The lock
1475          * order matches that in dlopen to avoid deadlock. */
1476         pthread_rwlock_wrlock(&lock);
1477         pthread_mutex_lock(&init_fini_lock);
1478         shutting_down = 1;
1479         pthread_rwlock_unlock(&lock);
1480         for (p=fini_head; p; p=p->fini_next) {
1481                 while (p->ctor_visitor && p->ctor_visitor!=self)
1482                         pthread_cond_wait(&ctor_cond, &init_fini_lock);
1483                 if (!p->constructed) continue;
1484                 decode_vec(p->dynv, dyn, DYN_CNT);
1485                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1486                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1487                         size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1488                         while (n--) ((void (*)(void))*--fn)();
1489                 }
1490 #ifndef NO_LEGACY_INITFINI
1491                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1492                         fpaddr(p, dyn[DT_FINI])();
1493 #endif
1494         }
1495 }
1496
1497 void __ldso_atfork(int who)
1498 {
1499         if (who<0) {
1500                 pthread_rwlock_wrlock(&lock);
1501                 pthread_mutex_lock(&init_fini_lock);
1502         } else {
1503                 pthread_mutex_unlock(&init_fini_lock);
1504                 pthread_rwlock_unlock(&lock);
1505         }
1506 }
1507
1508 static struct dso **queue_ctors(struct dso *dso)
1509 {
1510         size_t cnt, qpos, spos, i;
1511         struct dso *p, **queue, **stack;
1512
1513         if (ldd_mode) return 0;
1514
1515         /* Bound on queue size is the total number of indirect deps.
1516          * If a bfs deps list was built, we can use it. Otherwise,
1517          * bound by the total number of DSOs, which is always safe and
1518          * is reasonable we use it (for main app at startup). */
1519         if (dso->bfs_built) {
1520                 for (cnt=0; dso->deps[cnt]; cnt++)
1521                         dso->deps[cnt]->mark = 0;
1522                 cnt++; /* self, not included in deps */
1523         } else {
1524                 for (cnt=0, p=head; p; cnt++, p=p->next)
1525                         p->mark = 0;
1526         }
1527         cnt++; /* termination slot */
1528         if (dso==head && cnt <= countof(builtin_ctor_queue))
1529                 queue = builtin_ctor_queue;
1530         else
1531                 queue = calloc(cnt, sizeof *queue);
1532
1533         if (!queue) {
1534                 error("Error allocating constructor queue: %m\n");
1535                 if (runtime) longjmp(*rtld_fail, 1);
1536                 return 0;
1537         }
1538
1539         /* Opposite ends of the allocated buffer serve as an output queue
1540          * and a working stack. Setup initial stack with just the argument
1541          * dso and initial queue empty... */
1542         stack = queue;
1543         qpos = 0;
1544         spos = cnt;
1545         stack[--spos] = dso;
1546         dso->next_dep = 0;
1547         dso->mark = 1;
1548
1549         /* Then perform pseudo-DFS sort, but ignoring circular deps. */
1550         while (spos<cnt) {
1551                 p = stack[spos++];
1552                 while (p->next_dep < p->ndeps_direct) {
1553                         if (p->deps[p->next_dep]->mark) {
1554                                 p->next_dep++;
1555                         } else {
1556                                 stack[--spos] = p;
1557                                 p = p->deps[p->next_dep];
1558                                 p->next_dep = 0;
1559                                 p->mark = 1;
1560                         }
1561                 }
1562                 queue[qpos++] = p;
1563         }
1564         queue[qpos] = 0;
1565         for (i=0; i<qpos; i++) queue[i]->mark = 0;
1566         for (i=0; i<qpos; i++)
1567                 if (queue[i]->ctor_visitor && queue[i]->ctor_visitor->tid < 0) {
1568                         error("State of %s is inconsistent due to multithreaded fork\n",
1569                                 queue[i]->name);
1570                         free(queue);
1571                         if (runtime) longjmp(*rtld_fail, 1);
1572                 }
1573
1574         return queue;
1575 }
1576
1577 static void do_init_fini(struct dso **queue)
1578 {
1579         struct dso *p;
1580         size_t dyn[DYN_CNT], i;
1581         pthread_t self = __pthread_self();
1582
1583         pthread_mutex_lock(&init_fini_lock);
1584         for (i=0; (p=queue[i]); i++) {
1585                 while ((p->ctor_visitor && p->ctor_visitor!=self) || shutting_down)
1586                         pthread_cond_wait(&ctor_cond, &init_fini_lock);
1587                 if (p->ctor_visitor || p->constructed)
1588                         continue;
1589                 p->ctor_visitor = self;
1590
1591                 decode_vec(p->dynv, dyn, DYN_CNT);
1592                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1593                         p->fini_next = fini_head;
1594                         fini_head = p;
1595                 }
1596
1597                 pthread_mutex_unlock(&init_fini_lock);
1598
1599 #ifndef NO_LEGACY_INITFINI
1600                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1601                         fpaddr(p, dyn[DT_INIT])();
1602 #endif
1603                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1604                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1605                         size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1606                         while (n--) ((void (*)(void))*fn++)();
1607                 }
1608
1609                 pthread_mutex_lock(&init_fini_lock);
1610                 p->ctor_visitor = 0;
1611                 p->constructed = 1;
1612                 pthread_cond_broadcast(&ctor_cond);
1613         }
1614         pthread_mutex_unlock(&init_fini_lock);
1615 }
1616
1617 void __libc_start_init(void)
1618 {
1619         do_init_fini(main_ctor_queue);
1620         if (!__malloc_replaced && main_ctor_queue != builtin_ctor_queue)
1621                 free(main_ctor_queue);
1622         main_ctor_queue = 0;
1623 }
1624
1625 static void dl_debug_state(void)
1626 {
1627 }
1628
1629 weak_alias(dl_debug_state, _dl_debug_state);
1630
1631 void __init_tls(size_t *auxv)
1632 {
1633 }
1634
1635 static void update_tls_size()
1636 {
1637         libc.tls_cnt = tls_cnt;
1638         libc.tls_align = tls_align;
1639         libc.tls_size = ALIGN(
1640                 (1+tls_cnt) * sizeof(void *) +
1641                 tls_offset +
1642                 sizeof(struct pthread) +
1643                 tls_align * 2,
1644         tls_align);
1645 }
1646
1647 static void install_new_tls(void)
1648 {
1649         sigset_t set;
1650         pthread_t self = __pthread_self(), td;
1651         struct dso *dtv_provider = container_of(tls_tail, struct dso, tls);
1652         uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv;
1653         struct dso *p;
1654         size_t i, j;
1655         size_t old_cnt = self->dtv[0];
1656
1657         __block_app_sigs(&set);
1658         __tl_lock();
1659         /* Copy existing dtv contents from all existing threads. */
1660         for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1661                 memcpy(newdtv+i, td->dtv,
1662                         (old_cnt+1)*sizeof(uintptr_t));
1663                 newdtv[i][0] = tls_cnt;
1664         }
1665         /* Install new dtls into the enlarged, uninstalled dtv copies. */
1666         for (p=head; ; p=p->next) {
1667                 if (p->tls_id <= old_cnt) continue;
1668                 unsigned char *mem = p->new_tls;
1669                 for (j=0; j<i; j++) {
1670                         unsigned char *new = mem;
1671                         new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1672                                 & (p->tls.align-1);
1673                         memcpy(new, p->tls.image, p->tls.len);
1674                         newdtv[j][p->tls_id] =
1675                                 (uintptr_t)new + DTP_OFFSET;
1676                         mem += p->tls.size + p->tls.align;
1677                 }
1678                 if (p->tls_id == tls_cnt) break;
1679         }
1680
1681         /* Broadcast barrier to ensure contents of new dtv is visible
1682          * if the new dtv pointer is. The __membarrier function has a
1683          * fallback emulation using signals for kernels that lack the
1684          * feature at the syscall level. */
1685
1686         __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1687
1688         /* Install new dtv for each thread. */
1689         for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1690                 td->dtv = newdtv[j];
1691         }
1692
1693         __tl_unlock();
1694         __restore_sigs(&set);
1695 }
1696
1697 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1698  * following stage 2 and stage 3 functions via primitive symbolic lookup
1699  * since it does not have access to their addresses to begin with. */
1700
1701 /* Stage 2 of the dynamic linker is called after relative relocations
1702  * have been processed. It can make function calls to static functions
1703  * and access string literals and static data, but cannot use extern
1704  * symbols. Its job is to perform symbolic relocations on the dynamic
1705  * linker itself, but some of the relocations performed may need to be
1706  * replaced later due to copy relocations in the main program. */
1707
1708 hidden void __dls2(unsigned char *base, size_t *sp)
1709 {
1710         size_t *auxv;
1711         for (auxv=sp+1+*sp+1; *auxv; auxv++);
1712         auxv++;
1713         if (DL_FDPIC) {
1714                 void *p1 = (void *)sp[-2];
1715                 void *p2 = (void *)sp[-1];
1716                 if (!p1) {
1717                         size_t aux[AUX_CNT];
1718                         decode_vec(auxv, aux, AUX_CNT);
1719                         if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1720                         else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1721                 }
1722                 app_loadmap = p2 ? p1 : 0;
1723                 ldso.loadmap = p2 ? p2 : p1;
1724                 ldso.base = laddr(&ldso, 0);
1725         } else {
1726                 ldso.base = base;
1727         }
1728         Ehdr *ehdr = (void *)ldso.base;
1729         ldso.name = ldso.shortname = "libc.so";
1730         ldso.phnum = ehdr->e_phnum;
1731         ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1732         ldso.phentsize = ehdr->e_phentsize;
1733         search_vec(auxv, &ldso_page_size, AT_PAGESZ);
1734         kernel_mapped_dso(&ldso);
1735         decode_dyn(&ldso);
1736
1737         if (DL_FDPIC) makefuncdescs(&ldso);
1738
1739         /* Prepare storage for to save clobbered REL addends so they
1740          * can be reused in stage 3. There should be very few. If
1741          * something goes wrong and there are a huge number, abort
1742          * instead of risking stack overflow. */
1743         size_t dyn[DYN_CNT];
1744         decode_vec(ldso.dynv, dyn, DYN_CNT);
1745         size_t *rel = laddr(&ldso, dyn[DT_REL]);
1746         size_t rel_size = dyn[DT_RELSZ];
1747         size_t symbolic_rel_cnt = 0;
1748         apply_addends_to = rel;
1749         for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1750                 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1751         if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1752         size_t addends[symbolic_rel_cnt+1];
1753         saved_addends = addends;
1754
1755         head = &ldso;
1756         reloc_all(&ldso);
1757
1758         ldso.relocated = 0;
1759
1760         /* Call dynamic linker stage-2b, __dls2b, looking it up
1761          * symbolically as a barrier against moving the address
1762          * load across the above relocation processing. */
1763         struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1764         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp, auxv);
1765         else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp, auxv);
1766 }
1767
1768 /* Stage 2b sets up a valid thread pointer, which requires relocations
1769  * completed in stage 2, and on which stage 3 is permitted to depend.
1770  * This is done as a separate stage, with symbolic lookup as a barrier,
1771  * so that loads of the thread pointer and &errno can be pure/const and
1772  * thereby hoistable. */
1773
1774 void __dls2b(size_t *sp, size_t *auxv)
1775 {
1776         /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1777          * use during dynamic linking. If possible it will also serve as the
1778          * thread pointer at runtime. */
1779         search_vec(auxv, &__hwcap, AT_HWCAP);
1780         libc.auxv = auxv;
1781         libc.tls_size = sizeof builtin_tls;
1782         libc.tls_align = tls_align;
1783         if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1784                 a_crash();
1785         }
1786
1787         struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1788         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp, auxv);
1789         else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp, auxv);
1790 }
1791
1792 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1793  * fully functional. Its job is to load (if not already loaded) and
1794  * process dependencies and relocations for the main application and
1795  * transfer control to its entry point. */
1796
1797 void __dls3(size_t *sp, size_t *auxv)
1798 {
1799         static struct dso app, vdso;
1800         size_t aux[AUX_CNT];
1801         size_t i;
1802         char *env_preload=0;
1803         char *replace_argv0=0;
1804         size_t vdso_base;
1805         int argc = *sp;
1806         char **argv = (void *)(sp+1);
1807         char **argv_orig = argv;
1808         char **envp = argv+argc+1;
1809
1810         /* Find aux vector just past environ[] and use it to initialize
1811          * global data that may be needed before we can make syscalls. */
1812         __environ = envp;
1813         decode_vec(auxv, aux, AUX_CNT);
1814         search_vec(auxv, &__sysinfo, AT_SYSINFO);
1815         __pthread_self()->sysinfo = __sysinfo;
1816         libc.page_size = aux[AT_PAGESZ];
1817         libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1818                 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1819
1820         /* Only trust user/env if kernel says we're not suid/sgid */
1821         if (!libc.secure) {
1822                 env_path = getenv("LD_LIBRARY_PATH");
1823                 env_preload = getenv("LD_PRELOAD");
1824         }
1825
1826         /* Activate error handler function */
1827         error = error_impl;
1828
1829         /* If the main program was already loaded by the kernel,
1830          * AT_PHDR will point to some location other than the dynamic
1831          * linker's program headers. */
1832         if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1833                 size_t interp_off = 0;
1834                 size_t tls_image = 0;
1835                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1836                 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1837                 app.phnum = aux[AT_PHNUM];
1838                 app.phentsize = aux[AT_PHENT];
1839                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1840                         if (phdr->p_type == PT_PHDR)
1841                                 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1842                         else if (phdr->p_type == PT_INTERP)
1843                                 interp_off = (size_t)phdr->p_vaddr;
1844                         else if (phdr->p_type == PT_TLS) {
1845                                 tls_image = phdr->p_vaddr;
1846                                 app.tls.len = phdr->p_filesz;
1847                                 app.tls.size = phdr->p_memsz;
1848                                 app.tls.align = phdr->p_align;
1849                         }
1850                 }
1851                 if (DL_FDPIC) app.loadmap = app_loadmap;
1852                 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1853                 if (interp_off) ldso.name = laddr(&app, interp_off);
1854                 if ((aux[0] & (1UL<<AT_EXECFN))
1855                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1856                         app.name = (char *)aux[AT_EXECFN];
1857                 else
1858                         app.name = argv[0];
1859                 kernel_mapped_dso(&app);
1860         } else {
1861                 int fd;
1862                 char *ldname = argv[0];
1863                 size_t l = strlen(ldname);
1864                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1865                 argv++;
1866                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1867                         char *opt = argv[0]+2;
1868                         *argv++ = (void *)-1;
1869                         if (!*opt) {
1870                                 break;
1871                         } else if (!memcmp(opt, "list", 5)) {
1872                                 ldd_mode = 1;
1873                         } else if (!memcmp(opt, "library-path", 12)) {
1874                                 if (opt[12]=='=') env_path = opt+13;
1875                                 else if (opt[12]) *argv = 0;
1876                                 else if (*argv) env_path = *argv++;
1877                         } else if (!memcmp(opt, "preload", 7)) {
1878                                 if (opt[7]=='=') env_preload = opt+8;
1879                                 else if (opt[7]) *argv = 0;
1880                                 else if (*argv) env_preload = *argv++;
1881                         } else if (!memcmp(opt, "argv0", 5)) {
1882                                 if (opt[5]=='=') replace_argv0 = opt+6;
1883                                 else if (opt[5]) *argv = 0;
1884                                 else if (*argv) replace_argv0 = *argv++;
1885                         } else {
1886                                 argv[0] = 0;
1887                         }
1888                 }
1889                 argv[-1] = (void *)(argc - (argv-argv_orig));
1890                 if (!argv[0]) {
1891                         dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1892                                 "Version %s\n"
1893                                 "Dynamic Program Loader\n"
1894                                 "Usage: %s [options] [--] pathname%s\n",
1895                                 __libc_version, ldname,
1896                                 ldd_mode ? "" : " [args]");
1897                         _exit(1);
1898                 }
1899                 fd = open(argv[0], O_RDONLY);
1900                 if (fd < 0) {
1901                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1902                         _exit(1);
1903                 }
1904                 Ehdr *ehdr = map_library(fd, &app);
1905                 if (!ehdr) {
1906                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1907                         _exit(1);
1908                 }
1909                 close(fd);
1910                 ldso.name = ldname;
1911                 app.name = argv[0];
1912                 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1913                 /* Find the name that would have been used for the dynamic
1914                  * linker had ldd not taken its place. */
1915                 if (ldd_mode) {
1916                         for (i=0; i<app.phnum; i++) {
1917                                 if (app.phdr[i].p_type == PT_INTERP)
1918                                         ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1919                         }
1920                         dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1921                 }
1922         }
1923         if (app.tls.size) {
1924                 libc.tls_head = tls_tail = &app.tls;
1925                 app.tls_id = tls_cnt = 1;
1926 #ifdef TLS_ABOVE_TP
1927                 app.tls.offset = GAP_ABOVE_TP;
1928                 app.tls.offset += (-GAP_ABOVE_TP + (uintptr_t)app.tls.image)
1929                         & (app.tls.align-1);
1930                 tls_offset = app.tls.offset + app.tls.size;
1931 #else
1932                 tls_offset = app.tls.offset = app.tls.size
1933                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1934                         & (app.tls.align-1) );
1935 #endif
1936                 tls_align = MAXP2(tls_align, app.tls.align);
1937         }
1938         decode_dyn(&app);
1939         if (DL_FDPIC) {
1940                 makefuncdescs(&app);
1941                 if (!app.loadmap) {
1942                         app.loadmap = (void *)&app_dummy_loadmap;
1943                         app.loadmap->nsegs = 1;
1944                         app.loadmap->segs[0].addr = (size_t)app.map;
1945                         app.loadmap->segs[0].p_vaddr = (size_t)app.map
1946                                 - (size_t)app.base;
1947                         app.loadmap->segs[0].p_memsz = app.map_len;
1948                 }
1949                 argv[-3] = (void *)app.loadmap;
1950         }
1951
1952         /* Initial dso chain consists only of the app. */
1953         head = tail = syms_tail = &app;
1954
1955         /* Donate unused parts of app and library mapping to malloc */
1956         reclaim_gaps(&app);
1957         reclaim_gaps(&ldso);
1958
1959         /* Load preload/needed libraries, add symbols to global namespace. */
1960         ldso.deps = (struct dso **)no_deps;
1961         if (env_preload) load_preload(env_preload);
1962         load_deps(&app);
1963         for (struct dso *p=head; p; p=p->next)
1964                 add_syms(p);
1965
1966         /* Attach to vdso, if provided by the kernel, last so that it does
1967          * not become part of the global namespace.  */
1968         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1969                 Ehdr *ehdr = (void *)vdso_base;
1970                 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1971                 vdso.phnum = ehdr->e_phnum;
1972                 vdso.phentsize = ehdr->e_phentsize;
1973                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1974                         if (phdr->p_type == PT_DYNAMIC)
1975                                 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1976                         if (phdr->p_type == PT_LOAD)
1977                                 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1978                 }
1979                 vdso.name = "";
1980                 vdso.shortname = "linux-gate.so.1";
1981                 vdso.relocated = 1;
1982                 vdso.deps = (struct dso **)no_deps;
1983                 decode_dyn(&vdso);
1984                 vdso.prev = tail;
1985                 tail->next = &vdso;
1986                 tail = &vdso;
1987         }
1988
1989         for (i=0; app.dynv[i]; i+=2) {
1990                 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1991                         app.dynv[i+1] = (size_t)&debug;
1992                 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1993                         size_t *ptr = (size_t *) app.dynv[i+1];
1994                         *ptr = (size_t)&debug;
1995                 }
1996                 if (app.dynv[i]==DT_DEBUG_INDIRECT_REL) {
1997                         size_t *ptr = (size_t *)((size_t)&app.dynv[i] + app.dynv[i+1]);
1998                         *ptr = (size_t)&debug;
1999                 }
2000         }
2001
2002         /* This must be done before final relocations, since it calls
2003          * malloc, which may be provided by the application. Calling any
2004          * application code prior to the jump to its entry point is not
2005          * valid in our model and does not work with FDPIC, where there
2006          * are additional relocation-like fixups that only the entry point
2007          * code can see to perform. */
2008         main_ctor_queue = queue_ctors(&app);
2009
2010         /* Initial TLS must also be allocated before final relocations
2011          * might result in calloc being a call to application code. */
2012         update_tls_size();
2013         void *initial_tls = builtin_tls;
2014         if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
2015                 initial_tls = calloc(libc.tls_size, 1);
2016                 if (!initial_tls) {
2017                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
2018                                 argv[0], libc.tls_size);
2019                         _exit(127);
2020                 }
2021         }
2022         static_tls_cnt = tls_cnt;
2023
2024         /* The main program must be relocated LAST since it may contain
2025          * copy relocations which depend on libraries' relocations. */
2026         reloc_all(app.next);
2027         reloc_all(&app);
2028
2029         /* Actual copying to new TLS needs to happen after relocations,
2030          * since the TLS images might have contained relocated addresses. */
2031         if (initial_tls != builtin_tls) {
2032                 if (__init_tp(__copy_tls(initial_tls)) < 0) {
2033                         a_crash();
2034                 }
2035         } else {
2036                 size_t tmp_tls_size = libc.tls_size;
2037                 pthread_t self = __pthread_self();
2038                 /* Temporarily set the tls size to the full size of
2039                  * builtin_tls so that __copy_tls will use the same layout
2040                  * as it did for before. Then check, just to be safe. */
2041                 libc.tls_size = sizeof builtin_tls;
2042                 if (__copy_tls((void*)builtin_tls) != self) a_crash();
2043                 libc.tls_size = tmp_tls_size;
2044         }
2045
2046         if (ldso_fail) _exit(127);
2047         if (ldd_mode) _exit(0);
2048
2049         /* Determine if malloc was interposed by a replacement implementation
2050          * so that calloc and the memalign family can harden against the
2051          * possibility of incomplete replacement. */
2052         if (find_sym(head, "malloc", 1).dso != &ldso)
2053                 __malloc_replaced = 1;
2054         if (find_sym(head, "aligned_alloc", 1).dso != &ldso)
2055                 __aligned_alloc_replaced = 1;
2056
2057         /* Switch to runtime mode: any further failures in the dynamic
2058          * linker are a reportable failure rather than a fatal startup
2059          * error. */
2060         runtime = 1;
2061
2062         debug.ver = 1;
2063         debug.bp = dl_debug_state;
2064         debug.head = head;
2065         debug.base = ldso.base;
2066         debug.state = RT_CONSISTENT;
2067         _dl_debug_state();
2068
2069         if (replace_argv0) argv[0] = replace_argv0;
2070
2071         errno = 0;
2072
2073         CRTJMP((void *)aux[AT_ENTRY], argv-1);
2074         for(;;);
2075 }
2076
2077 static void prepare_lazy(struct dso *p)
2078 {
2079         size_t dyn[DYN_CNT], n, flags1=0;
2080         decode_vec(p->dynv, dyn, DYN_CNT);
2081         search_vec(p->dynv, &flags1, DT_FLAGS_1);
2082         if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
2083                 return;
2084         n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
2085         if (NEED_MIPS_GOT_RELOCS) {
2086                 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
2087                 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
2088                 n += i-j;
2089         }
2090         p->lazy = calloc(n, 3*sizeof(size_t));
2091         if (!p->lazy) {
2092                 error("Error preparing lazy relocation for %s: %m", p->name);
2093                 longjmp(*rtld_fail, 1);
2094         }
2095         p->lazy_next = lazy_head;
2096         lazy_head = p;
2097 }
2098
2099 void *dlopen(const char *file, int mode)
2100 {
2101         struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
2102         struct tls_module *orig_tls_tail;
2103         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
2104         size_t i;
2105         int cs;
2106         jmp_buf jb;
2107         struct dso **volatile ctor_queue = 0;
2108
2109         if (!file) return head;
2110
2111         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
2112         pthread_rwlock_wrlock(&lock);
2113         __inhibit_ptc();
2114
2115         debug.state = RT_ADD;
2116         _dl_debug_state();
2117
2118         p = 0;
2119         if (shutting_down) {
2120                 error("Cannot dlopen while program is exiting.");
2121                 goto end;
2122         }
2123         orig_tls_tail = tls_tail;
2124         orig_tls_cnt = tls_cnt;
2125         orig_tls_offset = tls_offset;
2126         orig_tls_align = tls_align;
2127         orig_lazy_head = lazy_head;
2128         orig_syms_tail = syms_tail;
2129         orig_tail = tail;
2130         noload = mode & RTLD_NOLOAD;
2131
2132         rtld_fail = &jb;
2133         if (setjmp(*rtld_fail)) {
2134                 /* Clean up anything new that was (partially) loaded */
2135                 revert_syms(orig_syms_tail);
2136                 for (p=orig_tail->next; p; p=next) {
2137                         next = p->next;
2138                         while (p->td_index) {
2139                                 void *tmp = p->td_index->next;
2140                                 free(p->td_index);
2141                                 p->td_index = tmp;
2142                         }
2143                         free(p->funcdescs);
2144                         if (p->rpath != p->rpath_orig)
2145                                 free(p->rpath);
2146                         free(p->deps);
2147                         unmap_library(p);
2148                         free(p);
2149                 }
2150                 free(ctor_queue);
2151                 ctor_queue = 0;
2152                 if (!orig_tls_tail) libc.tls_head = 0;
2153                 tls_tail = orig_tls_tail;
2154                 if (tls_tail) tls_tail->next = 0;
2155                 tls_cnt = orig_tls_cnt;
2156                 tls_offset = orig_tls_offset;
2157                 tls_align = orig_tls_align;
2158                 lazy_head = orig_lazy_head;
2159                 tail = orig_tail;
2160                 tail->next = 0;
2161                 p = 0;
2162                 goto end;
2163         } else p = load_library(file, head);
2164
2165         if (!p) {
2166                 error(noload ?
2167                         "Library %s is not already loaded" :
2168                         "Error loading shared library %s: %m",
2169                         file);
2170                 goto end;
2171         }
2172
2173         /* First load handling */
2174         load_deps(p);
2175         extend_bfs_deps(p);
2176         pthread_mutex_lock(&init_fini_lock);
2177         int constructed = p->constructed;
2178         pthread_mutex_unlock(&init_fini_lock);
2179         if (!constructed) ctor_queue = queue_ctors(p);
2180         if (!p->relocated && (mode & RTLD_LAZY)) {
2181                 prepare_lazy(p);
2182                 for (i=0; p->deps[i]; i++)
2183                         if (!p->deps[i]->relocated)
2184                                 prepare_lazy(p->deps[i]);
2185         }
2186         if (!p->relocated || (mode & RTLD_GLOBAL)) {
2187                 /* Make new symbols global, at least temporarily, so we can do
2188                  * relocations. If not RTLD_GLOBAL, this is reverted below. */
2189                 add_syms(p);
2190                 for (i=0; p->deps[i]; i++)
2191                         add_syms(p->deps[i]);
2192         }
2193         if (!p->relocated) {
2194                 reloc_all(p);
2195         }
2196
2197         /* If RTLD_GLOBAL was not specified, undo any new additions
2198          * to the global symbol table. This is a nop if the library was
2199          * previously loaded and already global. */
2200         if (!(mode & RTLD_GLOBAL))
2201                 revert_syms(orig_syms_tail);
2202
2203         /* Processing of deferred lazy relocations must not happen until
2204          * the new libraries are committed; otherwise we could end up with
2205          * relocations resolved to symbol definitions that get removed. */
2206         redo_lazy_relocs();
2207
2208         update_tls_size();
2209         if (tls_cnt != orig_tls_cnt)
2210                 install_new_tls();
2211         orig_tail = tail;
2212 end:
2213         debug.state = RT_CONSISTENT;
2214         _dl_debug_state();
2215         __release_ptc();
2216         if (p) gencnt++;
2217         pthread_rwlock_unlock(&lock);
2218         if (ctor_queue) {
2219                 do_init_fini(ctor_queue);
2220                 free(ctor_queue);
2221         }
2222         pthread_setcancelstate(cs, 0);
2223         return p;
2224 }
2225
2226 hidden int __dl_invalid_handle(void *h)
2227 {
2228         struct dso *p;
2229         for (p=head; p; p=p->next) if (h==p) return 0;
2230         error("Invalid library handle %p", (void *)h);
2231         return 1;
2232 }
2233
2234 static void *addr2dso(size_t a)
2235 {
2236         struct dso *p;
2237         size_t i;
2238         if (DL_FDPIC) for (p=head; p; p=p->next) {
2239                 i = count_syms(p);
2240                 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
2241                         return p;
2242         }
2243         for (p=head; p; p=p->next) {
2244                 if (DL_FDPIC && p->loadmap) {
2245                         for (i=0; i<p->loadmap->nsegs; i++) {
2246                                 if (a-p->loadmap->segs[i].p_vaddr
2247                                     < p->loadmap->segs[i].p_memsz)
2248                                         return p;
2249                         }
2250                 } else {
2251                         Phdr *ph = p->phdr;
2252                         size_t phcnt = p->phnum;
2253                         size_t entsz = p->phentsize;
2254                         size_t base = (size_t)p->base;
2255                         for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
2256                                 if (ph->p_type != PT_LOAD) continue;
2257                                 if (a-base-ph->p_vaddr < ph->p_memsz)
2258                                         return p;
2259                         }
2260                         if (a-(size_t)p->map < p->map_len)
2261                                 return 0;
2262                 }
2263         }
2264         return 0;
2265 }
2266
2267 static void *do_dlsym(struct dso *p, const char *s, void *ra)
2268 {
2269         int use_deps = 0;
2270         if (p == head || p == RTLD_DEFAULT) {
2271                 p = head;
2272         } else if (p == RTLD_NEXT) {
2273                 p = addr2dso((size_t)ra);
2274                 if (!p) p=head;
2275                 p = p->next;
2276         } else if (__dl_invalid_handle(p)) {
2277                 return 0;
2278         } else
2279                 use_deps = 1;
2280         struct symdef def = find_sym2(p, s, 0, use_deps);
2281         if (!def.sym) {
2282                 error("Symbol not found: %s", s);
2283                 return 0;
2284         }
2285         if ((def.sym->st_info&0xf) == STT_TLS)
2286                 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
2287         if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
2288                 return def.dso->funcdescs + (def.sym - def.dso->syms);
2289         return laddr(def.dso, def.sym->st_value);
2290 }
2291
2292 int dladdr(const void *addr_arg, Dl_info *info)
2293 {
2294         size_t addr = (size_t)addr_arg;
2295         struct dso *p;
2296         Sym *sym, *bestsym;
2297         uint32_t nsym;
2298         char *strings;
2299         size_t best = 0;
2300         size_t besterr = -1;
2301
2302         pthread_rwlock_rdlock(&lock);
2303         p = addr2dso(addr);
2304         pthread_rwlock_unlock(&lock);
2305
2306         if (!p) return 0;
2307
2308         sym = p->syms;
2309         strings = p->strings;
2310         nsym = count_syms(p);
2311
2312         if (DL_FDPIC) {
2313                 size_t idx = (addr-(size_t)p->funcdescs)
2314                         / sizeof(*p->funcdescs);
2315                 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2316                         best = (size_t)(p->funcdescs + idx);
2317                         bestsym = sym + idx;
2318                         besterr = 0;
2319                 }
2320         }
2321
2322         if (!best) for (; nsym; nsym--, sym++) {
2323                 if (sym->st_value
2324                  && (1<<(sym->st_info&0xf) & OK_TYPES)
2325                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
2326                         size_t symaddr = (size_t)laddr(p, sym->st_value);
2327                         if (symaddr > addr || symaddr <= best)
2328                                 continue;
2329                         best = symaddr;
2330                         bestsym = sym;
2331                         besterr = addr - symaddr;
2332                         if (addr == symaddr)
2333                                 break;
2334                 }
2335         }
2336
2337         if (best && besterr > bestsym->st_size-1) {
2338                 best = 0;
2339                 bestsym = 0;
2340         }
2341
2342         info->dli_fname = p->name;
2343         info->dli_fbase = p->map;
2344
2345         if (!best) {
2346                 info->dli_sname = 0;
2347                 info->dli_saddr = 0;
2348                 return 1;
2349         }
2350
2351         if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2352                 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2353         info->dli_sname = strings + bestsym->st_name;
2354         info->dli_saddr = (void *)best;
2355
2356         return 1;
2357 }
2358
2359 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2360 {
2361         void *res;
2362         pthread_rwlock_rdlock(&lock);
2363         res = do_dlsym(p, s, ra);
2364         pthread_rwlock_unlock(&lock);
2365         return res;
2366 }
2367
2368 hidden void *__dlsym_redir_time64(void *restrict p, const char *restrict s, void *restrict ra)
2369 {
2370 #if _REDIR_TIME64
2371         const char *suffix, *suffix2 = "";
2372         char redir[36];
2373
2374         /* Map the symbol name to a time64 version of itself according to the
2375          * pattern used for naming the redirected time64 symbols. */
2376         size_t l = strnlen(s, sizeof redir);
2377         if (l<4 || l==sizeof redir) goto no_redir;
2378         if (s[l-2]=='_' && s[l-1]=='r') {
2379                 l -= 2;
2380                 suffix2 = s+l;
2381         }
2382         if (l<4) goto no_redir;
2383         if (!strcmp(s+l-4, "time")) suffix = "64";
2384         else suffix = "_time64";
2385
2386         /* Use the presence of the remapped symbol name in libc to determine
2387          * whether it's one that requires time64 redirection; replace if so. */
2388         snprintf(redir, sizeof redir, "__%.*s%s%s", (int)l, s, suffix, suffix2);
2389         if (find_sym(&ldso, redir, 1).sym) s = redir;
2390 no_redir:
2391 #endif
2392         return __dlsym(p, s, ra);
2393 }
2394
2395 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2396 {
2397         struct dso *current;
2398         struct dl_phdr_info info;
2399         int ret = 0;
2400         for(current = head; current;) {
2401                 info.dlpi_addr      = (uintptr_t)current->base;
2402                 info.dlpi_name      = current->name;
2403                 info.dlpi_phdr      = current->phdr;
2404                 info.dlpi_phnum     = current->phnum;
2405                 info.dlpi_adds      = gencnt;
2406                 info.dlpi_subs      = 0;
2407                 info.dlpi_tls_modid = current->tls_id;
2408                 info.dlpi_tls_data = !current->tls_id ? 0 :
2409                         __tls_get_addr((tls_mod_off_t[]){current->tls_id,0});
2410
2411                 ret = (callback)(&info, sizeof (info), data);
2412
2413                 if (ret != 0) break;
2414
2415                 pthread_rwlock_rdlock(&lock);
2416                 current = current->next;
2417                 pthread_rwlock_unlock(&lock);
2418         }
2419         return ret;
2420 }
2421
2422 static void error_impl(const char *fmt, ...)
2423 {
2424         va_list ap;
2425         va_start(ap, fmt);
2426         if (!runtime) {
2427                 vdprintf(2, fmt, ap);
2428                 dprintf(2, "\n");
2429                 ldso_fail = 1;
2430                 va_end(ap);
2431                 return;
2432         }
2433         __dl_vseterr(fmt, ap);
2434         va_end(ap);
2435 }
2436
2437 static void error_noop(const char *fmt, ...)
2438 {
2439 }