compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp

   1 //===-- sanitizer_linux_libcdep.cpp ---------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is shared between AddressSanitizer and ThreadSanitizer
  10 // run-time libraries and implements linux-specific functions from
  11 // sanitizer_libc.h.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "sanitizer_platform.h"
  15
  16 #if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
  17     SANITIZER_SOLARIS
  18
  19 #  include "sanitizer_allocator_internal.h"
  20 #  include "sanitizer_atomic.h"
  21 #  include "sanitizer_common.h"
  22 #  include "sanitizer_file.h"
  23 #  include "sanitizer_flags.h"
  24 #  include "sanitizer_getauxval.h"
  25 #  include "sanitizer_glibc_version.h"
  26 #  include "sanitizer_linux.h"
  27 #  include "sanitizer_placement_new.h"
  28 #  include "sanitizer_procmaps.h"
  29 #  include "sanitizer_solaris.h"
  30
  31 #  if SANITIZER_NETBSD
  32 #    define _RTLD_SOURCE  // for __lwp_gettcb_fast() / __lwp_getprivate_fast()
  33 #  endif
  34
  35 #  include <dlfcn.h>  // for dlsym()
  36 #  include <link.h>
  37 #  include <pthread.h>
  38 #  include <signal.h>
  39 #  include <sys/mman.h>
  40 #  include <sys/resource.h>
  41 #  include <syslog.h>
  42
  43 #  if SANITIZER_GLIBC
  44 #    include <gnu/libc-version.h>
  45 #  endif
  46
  47 #  if !defined(ElfW)
  48 #    define ElfW(type) Elf_##type
  49 #  endif
  50
  51 #  if SANITIZER_FREEBSD
  52 #    include <pthread_np.h>
  53 #    include <sys/auxv.h>
  54 #    include <sys/sysctl.h>
  55 #    define pthread_getattr_np pthread_attr_get_np
  56 // The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
  57 // that, it was never implemented. So just define it to zero.
  58 #    undef MAP_NORESERVE
  59 #    define MAP_NORESERVE 0
  60 extern const Elf_Auxinfo *__elf_aux_vector;
  61 extern "C" int __sys_sigaction(int signum, const struct sigaction *act,
  62                                struct sigaction *oldact);
  63 #  endif
  64
  65 #  if SANITIZER_NETBSD
  66 #    include <lwp.h>
  67 #    include <sys/sysctl.h>
  68 #    include <sys/tls.h>
  69 #  endif
  70
  71 #  if SANITIZER_SOLARIS
  72 #    include <stddef.h>
  73 #    include <stdlib.h>
  74 #    include <thread.h>
  75 #  endif
  76
  77 #  if SANITIZER_ANDROID
  78 #    include <android/api-level.h>
  79 #    if !defined(CPU_COUNT) && !defined(__aarch64__)
  80 #      include <dirent.h>
  81 #      include <fcntl.h>
  82 struct __sanitizer::linux_dirent {
  83   long d_ino;
  84   off_t d_off;
  85   unsigned short d_reclen;
  86   char d_name[];
  87 };
  88 #    endif
  89 #  endif
  90
  91 #  if !SANITIZER_ANDROID
  92 #    include <elf.h>
  93 #    include <unistd.h>
  94 #  endif
  95
  96 namespace __sanitizer {
  97
  98 SANITIZER_WEAK_ATTRIBUTE int real_sigaction(int signum, const void *act,
  99                                             void *oldact);
 100
 101 int internal_sigaction(int signum, const void *act, void *oldact) {
 102 #  if SANITIZER_FREEBSD
 103   // On FreeBSD, call the sigaction syscall directly (part of libsys in FreeBSD
 104   // 15) since the libc version goes via a global interposing table. Due to
 105   // library initialization order the table can be relocated after the call to
 106   // InitializeDeadlySignals() which then crashes when dereferencing the
 107   // uninitialized pointer in libc.
 108   return __sys_sigaction(signum, (const struct sigaction *)act,
 109                          (struct sigaction *)oldact);
 110 #  else
 111 #    if !SANITIZER_GO
 112   if (&real_sigaction)
 113     return real_sigaction(signum, act, oldact);
 114 #    endif
 115   return sigaction(signum, (const struct sigaction *)act,
 116                    (struct sigaction *)oldact);
 117 #  endif
 118 }
 119
 120 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
 121                                 uptr *stack_bottom) {
 122   CHECK(stack_top);
 123   CHECK(stack_bottom);
 124   if (at_initialization) {
 125     // This is the main thread. Libpthread may not be initialized yet.
 126     struct rlimit rl;
 127     CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
 128
 129     // Find the mapping that contains a stack variable.
 130     MemoryMappingLayout proc_maps(/*cache_enabled*/ true);
 131     if (proc_maps.Error()) {
 132       *stack_top = *stack_bottom = 0;
 133       return;
 134     }
 135     MemoryMappedSegment segment;
 136     uptr prev_end = 0;
 137     while (proc_maps.Next(&segment)) {
 138       if ((uptr)&rl < segment.end)
 139         break;
 140       prev_end = segment.end;
 141     }
 142     CHECK((uptr)&rl >= segment.start && (uptr)&rl < segment.end);
 143
 144     // Get stacksize from rlimit, but clip it so that it does not overlap
 145     // with other mappings.
 146     uptr stacksize = rl.rlim_cur;
 147     if (stacksize > segment.end - prev_end)
 148       stacksize = segment.end - prev_end;
 149     // When running with unlimited stack size, we still want to set some limit.
 150     // The unlimited stack size is caused by 'ulimit -s unlimited'.
 151     // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
 152     if (stacksize > kMaxThreadStackSize)
 153       stacksize = kMaxThreadStackSize;
 154     *stack_top = segment.end;
 155     *stack_bottom = segment.end - stacksize;
 156
 157     uptr maxAddr = GetMaxUserVirtualAddress();
 158     // Edge case: the stack mapping on some systems may be off-by-one e.g.,
 159     //     fffffffdf000-1000000000000 rw-p 00000000 00:00 0 [stack]
 160     // instead of:
 161     //     fffffffdf000- ffffffffffff
 162     // The out-of-range stack_top can result in an invalid shadow address
 163     // calculation, since those usually assume the parameters are in range.
 164     if (*stack_top == maxAddr + 1)
 165       *stack_top = maxAddr;
 166     else
 167       CHECK_LE(*stack_top, maxAddr);
 168
 169     return;
 170   }
 171   uptr stacksize = 0;
 172   void *stackaddr = nullptr;
 173 #  if SANITIZER_SOLARIS
 174   stack_t ss;
 175   CHECK_EQ(thr_stksegment(&ss), 0);
 176   stacksize = ss.ss_size;
 177   stackaddr = (char *)ss.ss_sp - stacksize;
 178 #  else   // !SANITIZER_SOLARIS
 179   pthread_attr_t attr;
 180   pthread_attr_init(&attr);
 181   CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
 182   internal_pthread_attr_getstack(&attr, &stackaddr, &stacksize);
 183   pthread_attr_destroy(&attr);
 184 #  endif  // SANITIZER_SOLARIS
 185
 186   *stack_top = (uptr)stackaddr + stacksize;
 187   *stack_bottom = (uptr)stackaddr;
 188 }
 189
 190 #  if !SANITIZER_GO
 191 bool SetEnv(const char *name, const char *value) {
 192   void *f = dlsym(RTLD_NEXT, "setenv");
 193   if (!f)
 194     return false;
 195   typedef int (*setenv_ft)(const char *name, const char *value, int overwrite);
 196   setenv_ft setenv_f;
 197   CHECK_EQ(sizeof(setenv_f), sizeof(f));
 198   internal_memcpy(&setenv_f, &f, sizeof(f));
 199   return setenv_f(name, value, 1) == 0;
 200 }
 201 #  endif
 202
 203 // True if we can use dlpi_tls_data. glibc before 2.25 may leave NULL (BZ
 204 // #19826) so dlpi_tls_data cannot be used.
 205 //
 206 // musl before 1.2.3 and FreeBSD as of 12.2 incorrectly set dlpi_tls_data to
 207 // the TLS initialization image
 208 // https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254774
 209 __attribute__((unused)) static int g_use_dlpi_tls_data;
 210
 211 #  if SANITIZER_GLIBC && !SANITIZER_GO
 212 static void GetGLibcVersion(int *major, int *minor, int *patch) {
 213   const char *p = gnu_get_libc_version();
 214   *major = internal_simple_strtoll(p, &p, 10);
 215   // Caller does not expect anything else.
 216   CHECK_EQ(*major, 2);
 217   *minor = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
 218   *patch = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
 219 }
 220
 221 static uptr ThreadDescriptorSizeFallback() {
 222 #    if defined(__x86_64__) || defined(__i386__) || defined(__arm__) || \
 223         SANITIZER_RISCV64
 224   int major;
 225   int minor;
 226   int patch;
 227   GetGLibcVersion(&major, &minor, &patch);
 228 #    endif
 229
 230 #    if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
 231   /* sizeof(struct pthread) values from various glibc versions.  */
 232   if (SANITIZER_X32)
 233     return 1728;  // Assume only one particular version for x32.
 234   // For ARM sizeof(struct pthread) changed in Glibc 2.23.
 235   if (SANITIZER_ARM)
 236     return minor <= 22 ? 1120 : 1216;
 237   if (minor <= 3)
 238     return FIRST_32_SECOND_64(1104, 1696);
 239   if (minor == 4)
 240     return FIRST_32_SECOND_64(1120, 1728);
 241   if (minor == 5)
 242     return FIRST_32_SECOND_64(1136, 1728);
 243   if (minor <= 9)
 244     return FIRST_32_SECOND_64(1136, 1712);
 245   if (minor == 10)
 246     return FIRST_32_SECOND_64(1168, 1776);
 247   if (minor == 11 || (minor == 12 && patch == 1))
 248     return FIRST_32_SECOND_64(1168, 2288);
 249   if (minor <= 14)
 250     return FIRST_32_SECOND_64(1168, 2304);
 251   if (minor < 32)  // Unknown version
 252     return FIRST_32_SECOND_64(1216, 2304);
 253   // minor == 32
 254   return FIRST_32_SECOND_64(1344, 2496);
 255 #    endif
 256
 257 #    if SANITIZER_RISCV64
 258   // TODO: consider adding an optional runtime check for an unknown (untested)
 259   // glibc version
 260   if (minor <= 28)  // WARNING: the highest tested version is 2.29
 261     return 1772;    // no guarantees for this one
 262   if (minor <= 31)
 263     return 1772;  // tested against glibc 2.29, 2.31
 264   return 1936;    // tested against glibc 2.32
 265 #    endif
 266
 267 #    if defined(__s390__) || defined(__sparc__)
 268   // The size of a prefix of TCB including pthread::{specific_1stblock,specific}
 269   // suffices. Just return offsetof(struct pthread, specific_used), which hasn't
 270   // changed since 2007-05. Technically this applies to i386/x86_64 as well but
 271   // we call _dl_get_tls_static_info and need the precise size of struct
 272   // pthread.
 273   return FIRST_32_SECOND_64(524, 1552);
 274 #    endif
 275
 276 #    if defined(__mips__)
 277   // TODO(sagarthakur): add more values as per different glibc versions.
 278   return FIRST_32_SECOND_64(1152, 1776);
 279 #    endif
 280
 281 #    if SANITIZER_LOONGARCH64
 282   return 1856;  // from glibc 2.36
 283 #    endif
 284
 285 #    if defined(__aarch64__)
 286   // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
 287   return 1776;
 288 #    endif
 289
 290 #    if defined(__powerpc64__)
 291   return 1776;  // from glibc.ppc64le 2.20-8.fc21
 292 #    endif
 293 }
 294 #  endif  // SANITIZER_GLIBC && !SANITIZER_GO
 295
 296 #  if SANITIZER_FREEBSD && !SANITIZER_GO
 297 // FIXME: Implementation is very GLIBC specific, but it's used by FreeBSD.
 298 static uptr ThreadDescriptorSizeFallback() {
 299 #    if defined(__s390__) || defined(__sparc__)
 300   // The size of a prefix of TCB including pthread::{specific_1stblock,specific}
 301   // suffices. Just return offsetof(struct pthread, specific_used), which hasn't
 302   // changed since 2007-05. Technically this applies to i386/x86_64 as well but
 303   // we call _dl_get_tls_static_info and need the precise size of struct
 304   // pthread.
 305   return FIRST_32_SECOND_64(524, 1552);
 306 #    endif
 307
 308 #    if defined(__mips__)
 309   // TODO(sagarthakur): add more values as per different glibc versions.
 310   return FIRST_32_SECOND_64(1152, 1776);
 311 #    endif
 312
 313 #    if SANITIZER_LOONGARCH64
 314   return 1856;  // from glibc 2.36
 315 #    endif
 316
 317 #    if defined(__aarch64__)
 318   // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
 319   return 1776;
 320 #    endif
 321
 322 #    if defined(__powerpc64__)
 323   return 1776;  // from glibc.ppc64le 2.20-8.fc21
 324 #    endif
 325
 326   return 0;
 327 }
 328 #  endif  // SANITIZER_FREEBSD && !SANITIZER_GO
 329
 330 #  if (SANITIZER_FREEBSD || SANITIZER_GLIBC) && !SANITIZER_GO
 331 // On glibc x86_64, ThreadDescriptorSize() needs to be precise due to the usage
 332 // of g_tls_size. On other targets, ThreadDescriptorSize() is only used by lsan
 333 // to get the pointer to thread-specific data keys in the thread control block.
 334 // sizeof(struct pthread) from glibc.
 335 static uptr thread_descriptor_size;
 336
 337 uptr ThreadDescriptorSize() { return thread_descriptor_size; }
 338
 339 #    if SANITIZER_GLIBC
 340 __attribute__((unused)) static size_t g_tls_size;
 341 #    endif
 342
 343 void InitTlsSize() {
 344 #    if SANITIZER_GLIBC
 345   int major, minor, patch;
 346   GetGLibcVersion(&major, &minor, &patch);
 347   g_use_dlpi_tls_data = major == 2 && minor >= 25;
 348
 349   if (major == 2 && minor >= 34) {
 350     // _thread_db_sizeof_pthread is a GLIBC_PRIVATE symbol that is exported in
 351     // glibc 2.34 and later.
 352     if (unsigned *psizeof = static_cast<unsigned *>(
 353             dlsym(RTLD_DEFAULT, "_thread_db_sizeof_pthread"))) {
 354       thread_descriptor_size = *psizeof;
 355     }
 356   }
 357
 358 #      if defined(__aarch64__) || defined(__x86_64__) || \
 359           defined(__powerpc64__) || defined(__loongarch__)
 360   auto *get_tls_static_info = (void (*)(size_t *, size_t *))dlsym(
 361       RTLD_DEFAULT, "_dl_get_tls_static_info");
 362   size_t tls_align;
 363   // Can be null if static link.
 364   if (get_tls_static_info)
 365     get_tls_static_info(&g_tls_size, &tls_align);
 366 #      endif
 367
 368 #    endif  // SANITIZER_GLIBC
 369
 370   if (!thread_descriptor_size)
 371     thread_descriptor_size = ThreadDescriptorSizeFallback();
 372 }
 373
 374 #    if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64 || \
 375         SANITIZER_LOONGARCH64
 376 // TlsPreTcbSize includes size of struct pthread_descr and size of tcb
 377 // head structure. It lies before the static tls blocks.
 378 static uptr TlsPreTcbSize() {
 379 #      if defined(__mips__)
 380   const uptr kTcbHead = 16;  // sizeof (tcbhead_t)
 381 #      elif defined(__powerpc64__)
 382   const uptr kTcbHead = 88;  // sizeof (tcbhead_t)
 383 #      elif SANITIZER_RISCV64
 384   const uptr kTcbHead = 16;  // sizeof (tcbhead_t)
 385 #      elif SANITIZER_LOONGARCH64
 386   const uptr kTcbHead = 16;  // sizeof (tcbhead_t)
 387 #      endif
 388   const uptr kTlsAlign = 16;
 389   const uptr kTlsPreTcbSize =
 390       RoundUpTo(ThreadDescriptorSize() + kTcbHead, kTlsAlign);
 391   return kTlsPreTcbSize;
 392 }
 393 #    endif
 394 #  else   // (SANITIZER_FREEBSD || SANITIZER_GLIBC) && !SANITIZER_GO
 395 void InitTlsSize() {}
 396 uptr ThreadDescriptorSize() { return 0; }
 397 #  endif  // (SANITIZER_FREEBSD || SANITIZER_GLIBC) && !SANITIZER_GO
 398
 399 #  if (SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_SOLARIS) && \
 400       !SANITIZER_ANDROID && !SANITIZER_GO
 401 namespace {
 402 struct TlsBlock {
 403   uptr begin, end, align;
 404   size_t tls_modid;
 405   bool operator<(const TlsBlock &rhs) const { return begin < rhs.begin; }
 406 };
 407 }  // namespace
 408
 409 #    ifdef __s390__
 410 extern "C" uptr __tls_get_offset(void *arg);
 411
 412 static uptr TlsGetOffset(uptr ti_module, uptr ti_offset) {
 413   // The __tls_get_offset ABI requires %r12 to point to GOT and %r2 to be an
 414   // offset of a struct tls_index inside GOT. We don't possess either of the
 415   // two, so violate the letter of the "ELF Handling For Thread-Local
 416   // Storage" document and assume that the implementation just dereferences
 417   // %r2 + %r12.
 418   uptr tls_index[2] = {ti_module, ti_offset};
 419   register uptr r2 asm("2") = 0;
 420   register void *r12 asm("12") = tls_index;
 421   asm("basr %%r14, %[__tls_get_offset]"
 422       : "+r"(r2)
 423       : [__tls_get_offset] "r"(__tls_get_offset), "r"(r12)
 424       : "memory", "cc", "0", "1", "3", "4", "5", "14");
 425   return r2;
 426 }
 427 #    else
 428 extern "C" void *__tls_get_addr(size_t *);
 429 #    endif
 430
 431 static size_t main_tls_modid;
 432
 433 static int CollectStaticTlsBlocks(struct dl_phdr_info *info, size_t size,
 434                                   void *data) {
 435   size_t tls_modid;
 436 #    if SANITIZER_SOLARIS
 437   // dlpi_tls_modid is only available since Solaris 11.4 SRU 10.  Use
 438   // dlinfo(RTLD_DI_LINKMAP) instead which works on all of Solaris 11.3,
 439   // 11.4, and Illumos.  The tlsmodid of the executable was changed to 1 in
 440   // 11.4 to match other implementations.
 441   if (size >= offsetof(dl_phdr_info_test, dlpi_tls_modid))
 442     main_tls_modid = 1;
 443   else
 444     main_tls_modid = 0;
 445   g_use_dlpi_tls_data = 0;
 446   Rt_map *map;
 447   dlinfo(RTLD_SELF, RTLD_DI_LINKMAP, &map);
 448   tls_modid = map->rt_tlsmodid;
 449 #    else
 450   main_tls_modid = 1;
 451   tls_modid = info->dlpi_tls_modid;
 452 #    endif
 453
 454   if (tls_modid < main_tls_modid)
 455     return 0;
 456   uptr begin;
 457 #    if !SANITIZER_SOLARIS
 458   begin = (uptr)info->dlpi_tls_data;
 459 #    endif
 460   if (!g_use_dlpi_tls_data) {
 461     // Call __tls_get_addr as a fallback. This forces TLS allocation on glibc
 462     // and FreeBSD.
 463 #    ifdef __s390__
 464     begin = (uptr)__builtin_thread_pointer() + TlsGetOffset(tls_modid, 0);
 465 #    else
 466     size_t mod_and_off[2] = {tls_modid, 0};
 467     begin = (uptr)__tls_get_addr(mod_and_off);
 468 #    endif
 469   }
 470   for (unsigned i = 0; i != info->dlpi_phnum; ++i)
 471     if (info->dlpi_phdr[i].p_type == PT_TLS) {
 472       static_cast<InternalMmapVector<TlsBlock> *>(data)->push_back(
 473           TlsBlock{begin, begin + info->dlpi_phdr[i].p_memsz,
 474                    info->dlpi_phdr[i].p_align, tls_modid});
 475       break;
 476     }
 477   return 0;
 478 }
 479
 480 __attribute__((unused)) static void GetStaticTlsBoundary(uptr *addr, uptr *size,
 481                                                          uptr *align) {
 482   InternalMmapVector<TlsBlock> ranges;
 483   dl_iterate_phdr(CollectStaticTlsBlocks, &ranges);
 484   uptr len = ranges.size();
 485   Sort(ranges.begin(), len);
 486   // Find the range with tls_modid == main_tls_modid. For glibc, because
 487   // libc.so uses PT_TLS, this module is guaranteed to exist and is one of
 488   // the initially loaded modules.
 489   uptr one = 0;
 490   while (one != len && ranges[one].tls_modid != main_tls_modid) ++one;
 491   if (one == len) {
 492     // This may happen with musl if no module uses PT_TLS.
 493     *addr = 0;
 494     *size = 0;
 495     *align = 1;
 496     return;
 497   }
 498   // Find the maximum consecutive ranges. We consider two modules consecutive if
 499   // the gap is smaller than the alignment of the latter range. The dynamic
 500   // loader places static TLS blocks this way not to waste space.
 501   uptr l = one;
 502   *align = ranges[l].align;
 503   while (l != 0 && ranges[l].begin < ranges[l - 1].end + ranges[l].align)
 504     *align = Max(*align, ranges[--l].align);
 505   uptr r = one + 1;
 506   while (r != len && ranges[r].begin < ranges[r - 1].end + ranges[r].align)
 507     *align = Max(*align, ranges[r++].align);
 508   *addr = ranges[l].begin;
 509   *size = ranges[r - 1].end - ranges[l].begin;
 510 }
 511 #  endif  // (x86_64 || i386 || mips || ...) && (SANITIZER_FREEBSD ||
 512           // SANITIZER_LINUX) && !SANITIZER_ANDROID && !SANITIZER_GO
 513
 514 #  if SANITIZER_NETBSD
 515 static struct tls_tcb *ThreadSelfTlsTcb() {
 516   struct tls_tcb *tcb = nullptr;
 517 #    ifdef __HAVE___LWP_GETTCB_FAST
 518   tcb = (struct tls_tcb *)__lwp_gettcb_fast();
 519 #    elif defined(__HAVE___LWP_GETPRIVATE_FAST)
 520   tcb = (struct tls_tcb *)__lwp_getprivate_fast();
 521 #    endif
 522   return tcb;
 523 }
 524
 525 uptr ThreadSelf() { return (uptr)ThreadSelfTlsTcb()->tcb_pthread; }
 526
 527 int GetSizeFromHdr(struct dl_phdr_info *info, size_t size, void *data) {
 528   const Elf_Phdr *hdr = info->dlpi_phdr;
 529   const Elf_Phdr *last_hdr = hdr + info->dlpi_phnum;
 530
 531   for (; hdr != last_hdr; ++hdr) {
 532     if (hdr->p_type == PT_TLS && info->dlpi_tls_modid == 1) {
 533       *(uptr *)data = hdr->p_memsz;
 534       break;
 535     }
 536   }
 537   return 0;
 538 }
 539 #  endif  // SANITIZER_NETBSD
 540
 541 #  if SANITIZER_ANDROID
 542 // Bionic provides this API since S.
 543 extern "C" SANITIZER_WEAK_ATTRIBUTE void __libc_get_static_tls_bounds(void **,
 544                                                                       void **);
 545 #  endif
 546
 547 #  if !SANITIZER_GO
 548 static void GetTls(uptr *addr, uptr *size) {
 549 #    if SANITIZER_ANDROID
 550   if (&__libc_get_static_tls_bounds) {
 551     void *start_addr;
 552     void *end_addr;
 553     __libc_get_static_tls_bounds(&start_addr, &end_addr);
 554     *addr = reinterpret_cast<uptr>(start_addr);
 555     *size =
 556         reinterpret_cast<uptr>(end_addr) - reinterpret_cast<uptr>(start_addr);
 557   } else {
 558     *addr = 0;
 559     *size = 0;
 560   }
 561 #    elif SANITIZER_GLIBC && defined(__x86_64__)
 562   // For aarch64 and x86-64, use an O(1) approach which requires relatively
 563   // precise ThreadDescriptorSize. g_tls_size was initialized in InitTlsSize.
 564 #      if SANITIZER_X32
 565   asm("mov %%fs:8,%0" : "=r"(*addr));
 566 #      else
 567   asm("mov %%fs:16,%0" : "=r"(*addr));
 568 #      endif
 569   *size = g_tls_size;
 570   *addr -= *size;
 571   *addr += ThreadDescriptorSize();
 572 #    elif SANITIZER_GLIBC && defined(__aarch64__)
 573   *addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
 574           ThreadDescriptorSize();
 575   *size = g_tls_size + ThreadDescriptorSize();
 576 #    elif SANITIZER_GLIBC && defined(__loongarch__)
 577 #      ifdef __clang__
 578   *addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
 579           ThreadDescriptorSize();
 580 #      else
 581   asm("or %0,$tp,$zero" : "=r"(*addr));
 582   *addr -= ThreadDescriptorSize();
 583 #      endif
 584   *size = g_tls_size + ThreadDescriptorSize();
 585 #    elif SANITIZER_GLIBC && defined(__powerpc64__)
 586   // Workaround for glibc<2.25(?). 2.27 is known to not need this.
 587   uptr tp;
 588   asm("addi %0,13,-0x7000" : "=r"(tp));
 589   const uptr pre_tcb_size = TlsPreTcbSize();
 590   *addr = tp - pre_tcb_size;
 591   *size = g_tls_size + pre_tcb_size;
 592 #    elif SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_SOLARIS
 593   uptr align;
 594   GetStaticTlsBoundary(addr, size, &align);
 595 #      if defined(__x86_64__) || defined(__i386__) || defined(__s390__) || \
 596           defined(__sparc__)
 597   if (SANITIZER_GLIBC) {
 598 #        if defined(__x86_64__) || defined(__i386__)
 599     align = Max<uptr>(align, 64);
 600 #        else
 601     align = Max<uptr>(align, 16);
 602 #        endif
 603   }
 604   const uptr tp = RoundUpTo(*addr + *size, align);
 605
 606   // lsan requires the range to additionally cover the static TLS surplus
 607   // (elf/dl-tls.c defines 1664). Otherwise there may be false positives for
 608   // allocations only referenced by tls in dynamically loaded modules.
 609   if (SANITIZER_GLIBC)
 610     *size += 1644;
 611   else if (SANITIZER_FREEBSD)
 612     *size += 128;  // RTLD_STATIC_TLS_EXTRA
 613
 614   // Extend the range to include the thread control block. On glibc, lsan needs
 615   // the range to include pthread::{specific_1stblock,specific} so that
 616   // allocations only referenced by pthread_setspecific can be scanned. This may
 617   // underestimate by at most TLS_TCB_ALIGN-1 bytes but it should be fine
 618   // because the number of bytes after pthread::specific is larger.
 619   *addr = tp - RoundUpTo(*size, align);
 620   *size = tp - *addr + ThreadDescriptorSize();
 621 #      else
 622   if (SANITIZER_GLIBC)
 623     *size += 1664;
 624   else if (SANITIZER_FREEBSD)
 625     *size += 128;  // RTLD_STATIC_TLS_EXTRA
 626 #        if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64
 627   const uptr pre_tcb_size = TlsPreTcbSize();
 628   *addr -= pre_tcb_size;
 629   *size += pre_tcb_size;
 630 #        else
 631   // arm and aarch64 reserve two words at TP, so this underestimates the range.
 632   // However, this is sufficient for the purpose of finding the pointers to
 633   // thread-specific data keys.
 634   const uptr tcb_size = ThreadDescriptorSize();
 635   *addr -= tcb_size;
 636   *size += tcb_size;
 637 #        endif
 638 #      endif
 639 #    elif SANITIZER_NETBSD
 640   struct tls_tcb *const tcb = ThreadSelfTlsTcb();
 641   *addr = 0;
 642   *size = 0;
 643   if (tcb != 0) {
 644     // Find size (p_memsz) of dlpi_tls_modid 1 (TLS block of the main program).
 645     // ld.elf_so hardcodes the index 1.
 646     dl_iterate_phdr(GetSizeFromHdr, size);
 647
 648     if (*size != 0) {
 649       // The block has been found and tcb_dtv[1] contains the base address
 650       *addr = (uptr)tcb->tcb_dtv[1];
 651     }
 652   }
 653 #    else
 654 #      error "Unknown OS"
 655 #    endif
 656 }
 657 #  endif
 658
 659 #  if !SANITIZER_GO
 660 uptr GetTlsSize() {
 661 #    if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
 662         SANITIZER_SOLARIS
 663   uptr addr, size;
 664   GetTls(&addr, &size);
 665   return size;
 666 #    else
 667   return 0;
 668 #    endif
 669 }
 670 #  endif
 671
 672 void GetThreadStackAndTls(bool main, uptr *stk_begin, uptr *stk_end,
 673                           uptr *tls_begin, uptr *tls_end) {
 674 #  if SANITIZER_GO
 675   // Stub implementation for Go.
 676   *stk_begin = 0;
 677   *stk_end = 0;
 678   *tls_begin = 0;
 679   *tls_end = 0;
 680 #  else
 681   uptr tls_addr = 0;
 682   uptr tls_size = 0;
 683   GetTls(&tls_addr, &tls_size);
 684   *tls_begin = tls_addr;
 685   *tls_end = tls_addr + tls_size;
 686
 687   uptr stack_top, stack_bottom;
 688   GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
 689   *stk_begin = stack_bottom;
 690   *stk_end = stack_top;
 691
 692   if (!main) {
 693     // If stack and tls intersect, make them non-intersecting.
 694     if (*tls_begin > *stk_begin && *tls_begin < *stk_end) {
 695       if (*stk_end < *tls_end)
 696         *tls_end = *stk_end;
 697       *stk_end = *tls_begin;
 698     }
 699   }
 700 #  endif
 701 }
 702
 703 #  if !SANITIZER_FREEBSD
 704 typedef ElfW(Phdr) Elf_Phdr;
 705 #  endif
 706
 707 struct DlIteratePhdrData {
 708   InternalMmapVectorNoCtor<LoadedModule> *modules;
 709   bool first;
 710 };
 711
 712 static int AddModuleSegments(const char *module_name, dl_phdr_info *info,
 713                              InternalMmapVectorNoCtor<LoadedModule> *modules) {
 714   if (module_name[0] == '\0')
 715     return 0;
 716   LoadedModule cur_module;
 717   cur_module.set(module_name, info->dlpi_addr);
 718   for (int i = 0; i < (int)info->dlpi_phnum; i++) {
 719     const Elf_Phdr *phdr = &info->dlpi_phdr[i];
 720     if (phdr->p_type == PT_LOAD) {
 721       uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
 722       uptr cur_end = cur_beg + phdr->p_memsz;
 723       bool executable = phdr->p_flags & PF_X;
 724       bool writable = phdr->p_flags & PF_W;
 725       cur_module.addAddressRange(cur_beg, cur_end, executable, writable);
 726     } else if (phdr->p_type == PT_NOTE) {
 727 #  ifdef NT_GNU_BUILD_ID
 728       uptr off = 0;
 729       while (off + sizeof(ElfW(Nhdr)) < phdr->p_memsz) {
 730         auto *nhdr = reinterpret_cast<const ElfW(Nhdr) *>(info->dlpi_addr +
 731                                                           phdr->p_vaddr + off);
 732         constexpr auto kGnuNamesz = 4;  // "GNU" with NUL-byte.
 733         static_assert(kGnuNamesz % 4 == 0, "kGnuNameSize is aligned to 4.");
 734         if (nhdr->n_type == NT_GNU_BUILD_ID && nhdr->n_namesz == kGnuNamesz) {
 735           if (off + sizeof(ElfW(Nhdr)) + nhdr->n_namesz + nhdr->n_descsz >
 736               phdr->p_memsz) {
 737             // Something is very wrong, bail out instead of reading potentially
 738             // arbitrary memory.
 739             break;
 740           }
 741           const char *name =
 742               reinterpret_cast<const char *>(nhdr) + sizeof(*nhdr);
 743           if (internal_memcmp(name, "GNU", 3) == 0) {
 744             const char *value = reinterpret_cast<const char *>(nhdr) +
 745                                 sizeof(*nhdr) + kGnuNamesz;
 746             cur_module.setUuid(value, nhdr->n_descsz);
 747             break;
 748           }
 749         }
 750         off += sizeof(*nhdr) + RoundUpTo(nhdr->n_namesz, 4) +
 751                RoundUpTo(nhdr->n_descsz, 4);
 752       }
 753 #  endif
 754     }
 755   }
 756   modules->push_back(cur_module);
 757   return 0;
 758 }
 759
 760 static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
 761   DlIteratePhdrData *data = (DlIteratePhdrData *)arg;
 762   if (data->first) {
 763     InternalMmapVector<char> module_name(kMaxPathLength);
 764     data->first = false;
 765     // First module is the binary itself.
 766     ReadBinaryNameCached(module_name.data(), module_name.size());
 767     return AddModuleSegments(module_name.data(), info, data->modules);
 768   }
 769
 770   if (info->dlpi_name)
 771     return AddModuleSegments(info->dlpi_name, info, data->modules);
 772
 773   return 0;
 774 }
 775
 776 #  if SANITIZER_ANDROID && __ANDROID_API__ < 21
 777 extern "C" __attribute__((weak)) int dl_iterate_phdr(
 778     int (*)(struct dl_phdr_info *, size_t, void *), void *);
 779 #  endif
 780
 781 static bool requiresProcmaps() {
 782 #  if SANITIZER_ANDROID && __ANDROID_API__ <= 22
 783   // Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken.
 784   // The runtime check allows the same library to work with
 785   // both K and L (and future) Android releases.
 786   return AndroidGetApiLevel() <= ANDROID_LOLLIPOP_MR1;
 787 #  else
 788   return false;
 789 #  endif
 790 }
 791
 792 static void procmapsInit(InternalMmapVectorNoCtor<LoadedModule> *modules) {
 793   MemoryMappingLayout memory_mapping(/*cache_enabled*/ true);
 794   memory_mapping.DumpListOfModules(modules);
 795 }
 796
 797 void ListOfModules::init() {
 798   clearOrInit();
 799   if (requiresProcmaps()) {
 800     procmapsInit(&modules_);
 801   } else {
 802     DlIteratePhdrData data = {&modules_, true};
 803     dl_iterate_phdr(dl_iterate_phdr_cb, &data);
 804   }
 805 }
 806
 807 // When a custom loader is used, dl_iterate_phdr may not contain the full
 808 // list of modules. Allow callers to fall back to using procmaps.
 809 void ListOfModules::fallbackInit() {
 810   if (!requiresProcmaps()) {
 811     clearOrInit();
 812     procmapsInit(&modules_);
 813   } else {
 814     clear();
 815   }
 816 }
 817
 818 // getrusage does not give us the current RSS, only the max RSS.
 819 // Still, this is better than nothing if /proc/self/statm is not available
 820 // for some reason, e.g. due to a sandbox.
 821 static uptr GetRSSFromGetrusage() {
 822   struct rusage usage;
 823   if (getrusage(RUSAGE_SELF, &usage))  // Failed, probably due to a sandbox.
 824     return 0;
 825   return usage.ru_maxrss << 10;  // ru_maxrss is in Kb.
 826 }
 827
 828 uptr GetRSS() {
 829   if (!common_flags()->can_use_proc_maps_statm)
 830     return GetRSSFromGetrusage();
 831   fd_t fd = OpenFile("/proc/self/statm", RdOnly);
 832   if (fd == kInvalidFd)
 833     return GetRSSFromGetrusage();
 834   char buf[64];
 835   uptr len = internal_read(fd, buf, sizeof(buf) - 1);
 836   internal_close(fd);
 837   if ((sptr)len <= 0)
 838     return 0;
 839   buf[len] = 0;
 840   // The format of the file is:
 841   // 1084 89 69 11 0 79 0
 842   // We need the second number which is RSS in pages.
 843   char *pos = buf;
 844   // Skip the first number.
 845   while (*pos >= '0' && *pos <= '9') pos++;
 846   // Skip whitespaces.
 847   while (!(*pos >= '0' && *pos <= '9') && *pos != 0) pos++;
 848   // Read the number.
 849   uptr rss = 0;
 850   while (*pos >= '0' && *pos <= '9') rss = rss * 10 + *pos++ - '0';
 851   return rss * GetPageSizeCached();
 852 }
 853
 854 // sysconf(_SC_NPROCESSORS_{CONF,ONLN}) cannot be used on most platforms as
 855 // they allocate memory.
 856 u32 GetNumberOfCPUs() {
 857 #  if SANITIZER_FREEBSD || SANITIZER_NETBSD
 858   u32 ncpu;
 859   int req[2];
 860   uptr len = sizeof(ncpu);
 861   req[0] = CTL_HW;
 862   req[1] = HW_NCPU;
 863   CHECK_EQ(internal_sysctl(req, 2, &ncpu, &len, NULL, 0), 0);
 864   return ncpu;
 865 #  elif SANITIZER_ANDROID && !defined(CPU_COUNT) && !defined(__aarch64__)
 866   // Fall back to /sys/devices/system/cpu on Android when cpu_set_t doesn't
 867   // exist in sched.h. That is the case for toolchains generated with older
 868   // NDKs.
 869   // This code doesn't work on AArch64 because internal_getdents makes use of
 870   // the 64bit getdents syscall, but cpu_set_t seems to always exist on AArch64.
 871   uptr fd = internal_open("/sys/devices/system/cpu", O_RDONLY | O_DIRECTORY);
 872   if (internal_iserror(fd))
 873     return 0;
 874   InternalMmapVector<u8> buffer(4096);
 875   uptr bytes_read = buffer.size();
 876   uptr n_cpus = 0;
 877   u8 *d_type;
 878   struct linux_dirent *entry = (struct linux_dirent *)&buffer[bytes_read];
 879   while (true) {
 880     if ((u8 *)entry >= &buffer[bytes_read]) {
 881       bytes_read = internal_getdents(fd, (struct linux_dirent *)buffer.data(),
 882                                      buffer.size());
 883       if (internal_iserror(bytes_read) || !bytes_read)
 884         break;
 885       entry = (struct linux_dirent *)buffer.data();
 886     }
 887     d_type = (u8 *)entry + entry->d_reclen - 1;
 888     if (d_type >= &buffer[bytes_read] ||
 889         (u8 *)&entry->d_name[3] >= &buffer[bytes_read])
 890       break;
 891     if (entry->d_ino != 0 && *d_type == DT_DIR) {
 892       if (entry->d_name[0] == 'c' && entry->d_name[1] == 'p' &&
 893           entry->d_name[2] == 'u' && entry->d_name[3] >= '0' &&
 894           entry->d_name[3] <= '9')
 895         n_cpus++;
 896     }
 897     entry = (struct linux_dirent *)(((u8 *)entry) + entry->d_reclen);
 898   }
 899   internal_close(fd);
 900   return n_cpus;
 901 #  elif SANITIZER_SOLARIS
 902   return sysconf(_SC_NPROCESSORS_ONLN);
 903 #  else
 904   cpu_set_t CPUs;
 905   CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
 906   return CPU_COUNT(&CPUs);
 907 #  endif
 908 }
 909
 910 #  if SANITIZER_LINUX
 911
 912 #    if SANITIZER_ANDROID
 913 static atomic_uint8_t android_log_initialized;
 914
 915 void AndroidLogInit() {
 916   openlog(GetProcessName(), 0, LOG_USER);
 917   atomic_store(&android_log_initialized, 1, memory_order_release);
 918 }
 919
 920 static bool ShouldLogAfterPrintf() {
 921   return atomic_load(&android_log_initialized, memory_order_acquire);
 922 }
 923
 924 extern "C" SANITIZER_WEAK_ATTRIBUTE int async_safe_write_log(int pri,
 925                                                              const char *tag,
 926                                                              const char *msg);
 927 extern "C" SANITIZER_WEAK_ATTRIBUTE int __android_log_write(int prio,
 928                                                             const char *tag,
 929                                                             const char *msg);
 930
 931 // ANDROID_LOG_INFO is 4, but can't be resolved at runtime.
 932 #      define SANITIZER_ANDROID_LOG_INFO 4
 933
 934 // async_safe_write_log is a new public version of __libc_write_log that is
 935 // used behind syslog. It is preferable to syslog as it will not do any dynamic
 936 // memory allocation or formatting.
 937 // If the function is not available, syslog is preferred for L+ (it was broken
 938 // pre-L) as __android_log_write triggers a racey behavior with the strncpy
 939 // interceptor. Fallback to __android_log_write pre-L.
 940 void WriteOneLineToSyslog(const char *s) {
 941   if (&async_safe_write_log) {
 942     async_safe_write_log(SANITIZER_ANDROID_LOG_INFO, GetProcessName(), s);
 943   } else if (AndroidGetApiLevel() > ANDROID_KITKAT) {
 944     syslog(LOG_INFO, "%s", s);
 945   } else {
 946     CHECK(&__android_log_write);
 947     __android_log_write(SANITIZER_ANDROID_LOG_INFO, nullptr, s);
 948   }
 949 }
 950
 951 extern "C" SANITIZER_WEAK_ATTRIBUTE void android_set_abort_message(
 952     const char *);
 953
 954 void SetAbortMessage(const char *str) {
 955   if (&android_set_abort_message)
 956     android_set_abort_message(str);
 957 }
 958 #    else
 959 void AndroidLogInit() {}
 960
 961 static bool ShouldLogAfterPrintf() { return true; }
 962
 963 void WriteOneLineToSyslog(const char *s) { syslog(LOG_INFO, "%s", s); }
 964
 965 void SetAbortMessage(const char *str) {}
 966 #    endif  // SANITIZER_ANDROID
 967
 968 void LogMessageOnPrintf(const char *str) {
 969   if (common_flags()->log_to_syslog && ShouldLogAfterPrintf())
 970     WriteToSyslog(str);
 971 }
 972
 973 #  endif  // SANITIZER_LINUX
 974
 975 #  if SANITIZER_GLIBC && !SANITIZER_GO
 976 // glibc crashes when using clock_gettime from a preinit_array function as the
 977 // vDSO function pointers haven't been initialized yet. __progname is
 978 // initialized after the vDSO function pointers, so if it exists, is not null
 979 // and is not empty, we can use clock_gettime.
 980 extern "C" SANITIZER_WEAK_ATTRIBUTE char *__progname;
 981 inline bool CanUseVDSO() { return &__progname && __progname && *__progname; }
 982
 983 // MonotonicNanoTime is a timing function that can leverage the vDSO by calling
 984 // clock_gettime. real_clock_gettime only exists if clock_gettime is
 985 // intercepted, so define it weakly and use it if available.
 986 extern "C" SANITIZER_WEAK_ATTRIBUTE int real_clock_gettime(u32 clk_id,
 987                                                            void *tp);
 988 u64 MonotonicNanoTime() {
 989   timespec ts;
 990   if (CanUseVDSO()) {
 991     if (&real_clock_gettime)
 992       real_clock_gettime(CLOCK_MONOTONIC, &ts);
 993     else
 994       clock_gettime(CLOCK_MONOTONIC, &ts);
 995   } else {
 996     internal_clock_gettime(CLOCK_MONOTONIC, &ts);
 997   }
 998   return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
 999 }
1000 #  else
1001 // Non-glibc & Go always use the regular function.
1002 u64 MonotonicNanoTime() {
1003   timespec ts;
1004   clock_gettime(CLOCK_MONOTONIC, &ts);
1005   return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
1006 }
1007 #  endif  // SANITIZER_GLIBC && !SANITIZER_GO
1008
1009 void ReExec() {
1010   const char *pathname = "/proc/self/exe";
1011
1012 #  if SANITIZER_FREEBSD
1013   for (const auto *aux = __elf_aux_vector; aux->a_type != AT_NULL; aux++) {
1014     if (aux->a_type == AT_EXECPATH) {
1015       pathname = static_cast<const char *>(aux->a_un.a_ptr);
1016       break;
1017     }
1018   }
1019 #  elif SANITIZER_NETBSD
1020   static const int name[] = {
1021       CTL_KERN,
1022       KERN_PROC_ARGS,
1023       -1,
1024       KERN_PROC_PATHNAME,
1025   };
1026   char path[400];
1027   uptr len;
1028
1029   len = sizeof(path);
1030   if (internal_sysctl(name, ARRAY_SIZE(name), path, &len, NULL, 0) != -1)
1031     pathname = path;
1032 #  elif SANITIZER_SOLARIS
1033   pathname = getexecname();
1034   CHECK_NE(pathname, NULL);
1035 #  elif SANITIZER_USE_GETAUXVAL
1036   // Calling execve with /proc/self/exe sets that as $EXEC_ORIGIN. Binaries that
1037   // rely on that will fail to load shared libraries. Query AT_EXECFN instead.
1038   pathname = reinterpret_cast<const char *>(getauxval(AT_EXECFN));
1039 #  endif
1040
1041   uptr rv = internal_execve(pathname, GetArgv(), GetEnviron());
1042   int rverrno;
1043   CHECK_EQ(internal_iserror(rv, &rverrno), true);
1044   Printf("execve failed, errno %d\n", rverrno);
1045   Die();
1046 }
1047
1048 void UnmapFromTo(uptr from, uptr to) {
1049   if (to == from)
1050     return;
1051   CHECK(to >= from);
1052   uptr res = internal_munmap(reinterpret_cast<void *>(from), to - from);
1053   if (UNLIKELY(internal_iserror(res))) {
1054     Report("ERROR: %s failed to unmap 0x%zx (%zd) bytes at address %p\n",
1055            SanitizerToolName, to - from, to - from, (void *)from);
1056     CHECK("unable to unmap" && 0);
1057   }
1058 }
1059
1060 uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
1061                       uptr min_shadow_base_alignment, UNUSED uptr &high_mem_end,
1062                       uptr granularity) {
1063   const uptr alignment =
1064       Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
1065   const uptr left_padding =
1066       Max<uptr>(granularity, 1ULL << min_shadow_base_alignment);
1067
1068   const uptr shadow_size = RoundUpTo(shadow_size_bytes, granularity);
1069   const uptr map_size = shadow_size + left_padding + alignment;
1070
1071   const uptr map_start = (uptr)MmapNoAccess(map_size);
1072   CHECK_NE(map_start, ~(uptr)0);
1073
1074   const uptr shadow_start = RoundUpTo(map_start + left_padding, alignment);
1075
1076   UnmapFromTo(map_start, shadow_start - left_padding);
1077   UnmapFromTo(shadow_start + shadow_size, map_start + map_size);
1078
1079   return shadow_start;
1080 }
1081
1082 static uptr MmapSharedNoReserve(uptr addr, uptr size) {
1083   return internal_mmap(
1084       reinterpret_cast<void *>(addr), size, PROT_READ | PROT_WRITE,
1085       MAP_FIXED | MAP_SHARED | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
1086 }
1087
1088 static uptr MremapCreateAlias(uptr base_addr, uptr alias_addr,
1089                               uptr alias_size) {
1090 #  if SANITIZER_LINUX
1091   return internal_mremap(reinterpret_cast<void *>(base_addr), 0, alias_size,
1092                          MREMAP_MAYMOVE | MREMAP_FIXED,
1093                          reinterpret_cast<void *>(alias_addr));
1094 #  else
1095   CHECK(false && "mremap is not supported outside of Linux");
1096   return 0;
1097 #  endif
1098 }
1099
1100 static void CreateAliases(uptr start_addr, uptr alias_size, uptr num_aliases) {
1101   uptr total_size = alias_size * num_aliases;
1102   uptr mapped = MmapSharedNoReserve(start_addr, total_size);
1103   CHECK_EQ(mapped, start_addr);
1104
1105   for (uptr i = 1; i < num_aliases; ++i) {
1106     uptr alias_addr = start_addr + i * alias_size;
1107     CHECK_EQ(MremapCreateAlias(start_addr, alias_addr, alias_size), alias_addr);
1108   }
1109 }
1110
1111 uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size,
1112                                 uptr num_aliases, uptr ring_buffer_size) {
1113   CHECK_EQ(alias_size & (alias_size - 1), 0);
1114   CHECK_EQ(num_aliases & (num_aliases - 1), 0);
1115   CHECK_EQ(ring_buffer_size & (ring_buffer_size - 1), 0);
1116
1117   const uptr granularity = GetMmapGranularity();
1118   shadow_size = RoundUpTo(shadow_size, granularity);
1119   CHECK_EQ(shadow_size & (shadow_size - 1), 0);
1120
1121   const uptr alias_region_size = alias_size * num_aliases;
1122   const uptr alignment =
1123       2 * Max(Max(shadow_size, alias_region_size), ring_buffer_size);
1124   const uptr left_padding = ring_buffer_size;
1125
1126   const uptr right_size = alignment;
1127   const uptr map_size = left_padding + 2 * alignment;
1128
1129   const uptr map_start = reinterpret_cast<uptr>(MmapNoAccess(map_size));
1130   CHECK_NE(map_start, static_cast<uptr>(-1));
1131   const uptr right_start = RoundUpTo(map_start + left_padding, alignment);
1132
1133   UnmapFromTo(map_start, right_start - left_padding);
1134   UnmapFromTo(right_start + right_size, map_start + map_size);
1135
1136   CreateAliases(right_start + right_size / 2, alias_size, num_aliases);
1137
1138   return right_start;
1139 }
1140
1141 void InitializePlatformCommonFlags(CommonFlags *cf) {
1142 #  if SANITIZER_ANDROID
1143   if (&__libc_get_static_tls_bounds == nullptr)
1144     cf->detect_leaks = false;
1145 #  endif
1146 }
1147
1148 }  // namespace __sanitizer
1149
1150 #endif