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