libsanitizer/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_freebsd.h"
  25 #include "sanitizer_getauxval.h"
  26 #include "sanitizer_glibc_version.h"
  27 #include "sanitizer_linux.h"
  28 #include "sanitizer_placement_new.h"
  29 #include "sanitizer_procmaps.h"
  30 #include "sanitizer_solaris.h"
  31
  32 #if SANITIZER_NETBSD
  33 #define _RTLD_SOURCE  // for __lwp_gettcb_fast() / __lwp_getprivate_fast()
  34 #endif
  35
  36 #include <dlfcn.h>  // for dlsym()
  37 #include <link.h>
  38 #include <pthread.h>
  39 #include <signal.h>
  40 #include <sys/mman.h>
  41 #include <sys/resource.h>
  42 #include <syslog.h>
  43
  44 #if !defined(ElfW)
  45 #define ElfW(type) Elf_##type
  46 #endif
  47
  48 #if SANITIZER_FREEBSD
  49 #include <pthread_np.h>
  50 #include <osreldate.h>
  51 #include <sys/sysctl.h>
  52 #define pthread_getattr_np pthread_attr_get_np
  53 // The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
  54 // that, it was never implemented. So just define it to zero.
  55 #undef MAP_NORESERVE
  56 #define MAP_NORESERVE 0
  57 #endif
  58
  59 #if SANITIZER_NETBSD
  60 #include <sys/sysctl.h>
  61 #include <sys/tls.h>
  62 #include <lwp.h>
  63 #endif
  64
  65 #if SANITIZER_SOLARIS
  66 #include <stddef.h>
  67 #include <stdlib.h>
  68 #include <thread.h>
  69 #endif
  70
  71 #if SANITIZER_ANDROID
  72 #include <android/api-level.h>
  73 #if !defined(CPU_COUNT) && !defined(__aarch64__)
  74 #include <dirent.h>
  75 #include <fcntl.h>
  76 struct __sanitizer::linux_dirent {
  77   long           d_ino;
  78   off_t          d_off;
  79   unsigned short d_reclen;
  80   char           d_name[];
  81 };
  82 #endif
  83 #endif
  84
  85 #if !SANITIZER_ANDROID
  86 #include <elf.h>
  87 #include <unistd.h>
  88 #endif
  89
  90 namespace __sanitizer {
  91
  92 SANITIZER_WEAK_ATTRIBUTE int
  93 real_sigaction(int signum, const void *act, void *oldact);
  94
  95 int internal_sigaction(int signum, const void *act, void *oldact) {
  96 #if !SANITIZER_GO
  97   if (&real_sigaction)
  98     return real_sigaction(signum, act, oldact);
  99 #endif
 100   return sigaction(signum, (const struct sigaction *)act,
 101                    (struct sigaction *)oldact);
 102 }
 103
 104 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
 105                                 uptr *stack_bottom) {
 106   CHECK(stack_top);
 107   CHECK(stack_bottom);
 108   if (at_initialization) {
 109     // This is the main thread. Libpthread may not be initialized yet.
 110     struct rlimit rl;
 111     CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
 112
 113     // Find the mapping that contains a stack variable.
 114     MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 115     if (proc_maps.Error()) {
 116       *stack_top = *stack_bottom = 0;
 117       return;
 118     }
 119     MemoryMappedSegment segment;
 120     uptr prev_end = 0;
 121     while (proc_maps.Next(&segment)) {
 122       if ((uptr)&rl < segment.end) break;
 123       prev_end = segment.end;
 124     }
 125     CHECK((uptr)&rl >= segment.start && (uptr)&rl < segment.end);
 126
 127     // Get stacksize from rlimit, but clip it so that it does not overlap
 128     // with other mappings.
 129     uptr stacksize = rl.rlim_cur;
 130     if (stacksize > segment.end - prev_end) stacksize = segment.end - prev_end;
 131     // When running with unlimited stack size, we still want to set some limit.
 132     // The unlimited stack size is caused by 'ulimit -s unlimited'.
 133     // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
 134     if (stacksize > kMaxThreadStackSize)
 135       stacksize = kMaxThreadStackSize;
 136     *stack_top = segment.end;
 137     *stack_bottom = segment.end - stacksize;
 138     return;
 139   }
 140   uptr stacksize = 0;
 141   void *stackaddr = nullptr;
 142 #if SANITIZER_SOLARIS
 143   stack_t ss;
 144   CHECK_EQ(thr_stksegment(&ss), 0);
 145   stacksize = ss.ss_size;
 146   stackaddr = (char *)ss.ss_sp - stacksize;
 147 #else  // !SANITIZER_SOLARIS
 148   pthread_attr_t attr;
 149   pthread_attr_init(&attr);
 150   CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
 151   internal_pthread_attr_getstack(&attr, &stackaddr, &stacksize);
 152   pthread_attr_destroy(&attr);
 153 #endif  // SANITIZER_SOLARIS
 154
 155   *stack_top = (uptr)stackaddr + stacksize;
 156   *stack_bottom = (uptr)stackaddr;
 157 }
 158
 159 #if !SANITIZER_GO
 160 bool SetEnv(const char *name, const char *value) {
 161   void *f = dlsym(RTLD_NEXT, "setenv");
 162   if (!f)
 163     return false;
 164   typedef int(*setenv_ft)(const char *name, const char *value, int overwrite);
 165   setenv_ft setenv_f;
 166   CHECK_EQ(sizeof(setenv_f), sizeof(f));
 167   internal_memcpy(&setenv_f, &f, sizeof(f));
 168   return setenv_f(name, value, 1) == 0;
 169 }
 170 #endif
 171
 172 __attribute__((unused)) static bool GetLibcVersion(int *major, int *minor,
 173                                                    int *patch) {
 174 #ifdef _CS_GNU_LIBC_VERSION
 175   char buf[64];
 176   uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
 177   if (len >= sizeof(buf))
 178     return false;
 179   buf[len] = 0;
 180   static const char kGLibC[] = "glibc ";
 181   if (internal_strncmp(buf, kGLibC, sizeof(kGLibC) - 1) != 0)
 182     return false;
 183   const char *p = buf + sizeof(kGLibC) - 1;
 184   *major = internal_simple_strtoll(p, &p, 10);
 185   *minor = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
 186   *patch = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
 187   return true;
 188 #else
 189   return false;
 190 #endif
 191 }
 192
 193 // True if we can use dlpi_tls_data. glibc before 2.25 may leave NULL (BZ
 194 // #19826) so dlpi_tls_data cannot be used.
 195 //
 196 // musl before 1.2.3 and FreeBSD as of 12.2 incorrectly set dlpi_tls_data to
 197 // the TLS initialization image
 198 // https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254774
 199 __attribute__((unused)) static int g_use_dlpi_tls_data;
 200
 201 #if SANITIZER_GLIBC && !SANITIZER_GO
 202 __attribute__((unused)) static size_t g_tls_size;
 203 void InitTlsSize() {
 204   int major, minor, patch;
 205   g_use_dlpi_tls_data =
 206       GetLibcVersion(&major, &minor, &patch) && major == 2 && minor >= 25;
 207
 208 #if defined(__aarch64__) || defined(__x86_64__) || defined(__powerpc64__) || \
 209     defined(__loongarch__)
 210   void *get_tls_static_info = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
 211   size_t tls_align;
 212   ((void (*)(size_t *, size_t *))get_tls_static_info)(&g_tls_size, &tls_align);
 213 #endif
 214 }
 215 #else
 216 void InitTlsSize() { }
 217 #endif  // SANITIZER_GLIBC && !SANITIZER_GO
 218
 219 // On glibc x86_64, ThreadDescriptorSize() needs to be precise due to the usage
 220 // of g_tls_size. On other targets, ThreadDescriptorSize() is only used by lsan
 221 // to get the pointer to thread-specific data keys in the thread control block.
 222 #if (SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_SOLARIS) && \
 223     !SANITIZER_ANDROID && !SANITIZER_GO
 224 // sizeof(struct pthread) from glibc.
 225 static atomic_uintptr_t thread_descriptor_size;
 226
 227 static uptr ThreadDescriptorSizeFallback() {
 228   uptr val = 0;
 229 #if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
 230   int major;
 231   int minor;
 232   int patch;
 233   if (GetLibcVersion(&major, &minor, &patch) && major == 2) {
 234     /* sizeof(struct pthread) values from various glibc versions.  */
 235     if (SANITIZER_X32)
 236       val = 1728; // Assume only one particular version for x32.
 237     // For ARM sizeof(struct pthread) changed in Glibc 2.23.
 238     else if (SANITIZER_ARM)
 239       val = minor <= 22 ? 1120 : 1216;
 240     else if (minor <= 3)
 241       val = FIRST_32_SECOND_64(1104, 1696);
 242     else if (minor == 4)
 243       val = FIRST_32_SECOND_64(1120, 1728);
 244     else if (minor == 5)
 245       val = FIRST_32_SECOND_64(1136, 1728);
 246     else if (minor <= 9)
 247       val = FIRST_32_SECOND_64(1136, 1712);
 248     else if (minor == 10)
 249       val = FIRST_32_SECOND_64(1168, 1776);
 250     else if (minor == 11 || (minor == 12 && patch == 1))
 251       val = FIRST_32_SECOND_64(1168, 2288);
 252     else if (minor <= 14)
 253       val = FIRST_32_SECOND_64(1168, 2304);
 254     else if (minor < 32)  // Unknown version
 255       val = FIRST_32_SECOND_64(1216, 2304);
 256     else  // minor == 32
 257       val = FIRST_32_SECOND_64(1344, 2496);
 258   }
 259 #elif defined(__s390__) || defined(__sparc__)
 260   // The size of a prefix of TCB including pthread::{specific_1stblock,specific}
 261   // suffices. Just return offsetof(struct pthread, specific_used), which hasn't
 262   // changed since 2007-05. Technically this applies to i386/x86_64 as well but
 263   // we call _dl_get_tls_static_info and need the precise size of struct
 264   // pthread.
 265   return FIRST_32_SECOND_64(524, 1552);
 266 #elif defined(__mips__)
 267   // TODO(sagarthakur): add more values as per different glibc versions.
 268   val = FIRST_32_SECOND_64(1152, 1776);
 269 #elif SANITIZER_LOONGARCH64
 270   val = 1856; // from glibc 2.36
 271 #elif SANITIZER_RISCV64
 272   int major;
 273   int minor;
 274   int patch;
 275   if (GetLibcVersion(&major, &minor, &patch) && major == 2) {
 276     // TODO: consider adding an optional runtime check for an unknown (untested)
 277     // glibc version
 278     if (minor <= 28)  // WARNING: the highest tested version is 2.29
 279       val = 1772;     // no guarantees for this one
 280     else if (minor <= 31)
 281       val = 1772;  // tested against glibc 2.29, 2.31
 282     else
 283       val = 1936;  // tested against glibc 2.32
 284   }
 285
 286 #elif defined(__aarch64__)
 287   // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
 288   val = 1776;
 289 #elif defined(__powerpc64__)
 290   val = 1776; // from glibc.ppc64le 2.20-8.fc21
 291 #endif
 292   return val;
 293 }
 294
 295 uptr ThreadDescriptorSize() {
 296   uptr val = atomic_load_relaxed(&thread_descriptor_size);
 297   if (val)
 298     return val;
 299   // _thread_db_sizeof_pthread is a GLIBC_PRIVATE symbol that is exported in
 300   // glibc 2.34 and later.
 301   if (unsigned *psizeof = static_cast<unsigned *>(
 302           dlsym(RTLD_DEFAULT, "_thread_db_sizeof_pthread")))
 303     val = *psizeof;
 304   if (!val)
 305     val = ThreadDescriptorSizeFallback();
 306   atomic_store_relaxed(&thread_descriptor_size, val);
 307   return val;
 308 }
 309
 310 #if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64 || \
 311     SANITIZER_LOONGARCH64
 312 // TlsPreTcbSize includes size of struct pthread_descr and size of tcb
 313 // head structure. It lies before the static tls blocks.
 314 static uptr TlsPreTcbSize() {
 315 #if defined(__mips__)
 316   const uptr kTcbHead = 16; // sizeof (tcbhead_t)
 317 #elif defined(__powerpc64__)
 318   const uptr kTcbHead = 88; // sizeof (tcbhead_t)
 319 #elif SANITIZER_RISCV64
 320   const uptr kTcbHead = 16;  // sizeof (tcbhead_t)
 321 #elif SANITIZER_LOONGARCH64
 322   const uptr kTcbHead = 16;  // sizeof (tcbhead_t)
 323 #endif
 324   const uptr kTlsAlign = 16;
 325   const uptr kTlsPreTcbSize =
 326       RoundUpTo(ThreadDescriptorSize() + kTcbHead, kTlsAlign);
 327   return kTlsPreTcbSize;
 328 }
 329 #endif
 330
 331 namespace {
 332 struct TlsBlock {
 333   uptr begin, end, align;
 334   size_t tls_modid;
 335   bool operator<(const TlsBlock &rhs) const { return begin < rhs.begin; }
 336 };
 337 }  // namespace
 338
 339 #ifdef __s390__
 340 extern "C" uptr __tls_get_offset(void *arg);
 341
 342 static uptr TlsGetOffset(uptr ti_module, uptr ti_offset) {
 343   // The __tls_get_offset ABI requires %r12 to point to GOT and %r2 to be an
 344   // offset of a struct tls_index inside GOT. We don't possess either of the
 345   // two, so violate the letter of the "ELF Handling For Thread-Local
 346   // Storage" document and assume that the implementation just dereferences
 347   // %r2 + %r12.
 348   uptr tls_index[2] = {ti_module, ti_offset};
 349   register uptr r2 asm("2") = 0;
 350   register void *r12 asm("12") = tls_index;
 351   asm("basr %%r14, %[__tls_get_offset]"
 352       : "+r"(r2)
 353       : [__tls_get_offset] "r"(__tls_get_offset), "r"(r12)
 354       : "memory", "cc", "0", "1", "3", "4", "5", "14");
 355   return r2;
 356 }
 357 #else
 358 extern "C" void *__tls_get_addr(size_t *);
 359 #endif
 360
 361 static size_t main_tls_modid;
 362
 363 static int CollectStaticTlsBlocks(struct dl_phdr_info *info, size_t size,
 364                                   void *data) {
 365   size_t tls_modid;
 366 #if SANITIZER_SOLARIS
 367   // dlpi_tls_modid is only available since Solaris 11.4 SRU 10.  Use
 368   // dlinfo(RTLD_DI_LINKMAP) instead which works on all of Solaris 11.3,
 369   // 11.4, and Illumos.  The tlsmodid of the executable was changed to 1 in
 370   // 11.4 to match other implementations.
 371   if (size >= offsetof(dl_phdr_info_test, dlpi_tls_modid))
 372     main_tls_modid = 1;
 373   else
 374     main_tls_modid = 0;
 375   g_use_dlpi_tls_data = 0;
 376   Rt_map *map;
 377   dlinfo(RTLD_SELF, RTLD_DI_LINKMAP, &map);
 378   tls_modid = map->rt_tlsmodid;
 379 #else
 380   main_tls_modid = 1;
 381   tls_modid = info->dlpi_tls_modid;
 382 #endif
 383
 384   if (tls_modid < main_tls_modid)
 385     return 0;
 386   uptr begin;
 387 #if !SANITIZER_SOLARIS
 388   begin = (uptr)info->dlpi_tls_data;
 389 #endif
 390   if (!g_use_dlpi_tls_data) {
 391     // Call __tls_get_addr as a fallback. This forces TLS allocation on glibc
 392     // and FreeBSD.
 393 #ifdef __s390__
 394     begin = (uptr)__builtin_thread_pointer() +
 395             TlsGetOffset(tls_modid, 0);
 396 #else
 397     size_t mod_and_off[2] = {tls_modid, 0};
 398     begin = (uptr)__tls_get_addr(mod_and_off);
 399 #endif
 400   }
 401   for (unsigned i = 0; i != info->dlpi_phnum; ++i)
 402     if (info->dlpi_phdr[i].p_type == PT_TLS) {
 403       static_cast<InternalMmapVector<TlsBlock> *>(data)->push_back(
 404           TlsBlock{begin, begin + info->dlpi_phdr[i].p_memsz,
 405                    info->dlpi_phdr[i].p_align, tls_modid});
 406       break;
 407     }
 408   return 0;
 409 }
 410
 411 __attribute__((unused)) static void GetStaticTlsBoundary(uptr *addr, uptr *size,
 412                                                          uptr *align) {
 413   InternalMmapVector<TlsBlock> ranges;
 414   dl_iterate_phdr(CollectStaticTlsBlocks, &ranges);
 415   uptr len = ranges.size();
 416   Sort(ranges.begin(), len);
 417   // Find the range with tls_modid == main_tls_modid. For glibc, because
 418   // libc.so uses PT_TLS, this module is guaranteed to exist and is one of
 419   // the initially loaded modules.
 420   uptr one = 0;
 421   while (one != len && ranges[one].tls_modid != main_tls_modid) ++one;
 422   if (one == len) {
 423     // This may happen with musl if no module uses PT_TLS.
 424     *addr = 0;
 425     *size = 0;
 426     *align = 1;
 427     return;
 428   }
 429   // Find the maximum consecutive ranges. We consider two modules consecutive if
 430   // the gap is smaller than the alignment of the latter range. The dynamic
 431   // loader places static TLS blocks this way not to waste space.
 432   uptr l = one;
 433   *align = ranges[l].align;
 434   while (l != 0 && ranges[l].begin < ranges[l - 1].end + ranges[l].align)
 435     *align = Max(*align, ranges[--l].align);
 436   uptr r = one + 1;
 437   while (r != len && ranges[r].begin < ranges[r - 1].end + ranges[r].align)
 438     *align = Max(*align, ranges[r++].align);
 439   *addr = ranges[l].begin;
 440   *size = ranges[r - 1].end - ranges[l].begin;
 441 }
 442 #endif  // (x86_64 || i386 || mips || ...) && (SANITIZER_FREEBSD ||
 443         // SANITIZER_LINUX) && !SANITIZER_ANDROID && !SANITIZER_GO
 444
 445 #if SANITIZER_NETBSD
 446 static struct tls_tcb * ThreadSelfTlsTcb() {
 447   struct tls_tcb *tcb = nullptr;
 448 #ifdef __HAVE___LWP_GETTCB_FAST
 449   tcb = (struct tls_tcb *)__lwp_gettcb_fast();
 450 #elif defined(__HAVE___LWP_GETPRIVATE_FAST)
 451   tcb = (struct tls_tcb *)__lwp_getprivate_fast();
 452 #endif
 453   return tcb;
 454 }
 455
 456 uptr ThreadSelf() {
 457   return (uptr)ThreadSelfTlsTcb()->tcb_pthread;
 458 }
 459
 460 int GetSizeFromHdr(struct dl_phdr_info *info, size_t size, void *data) {
 461   const Elf_Phdr *hdr = info->dlpi_phdr;
 462   const Elf_Phdr *last_hdr = hdr + info->dlpi_phnum;
 463
 464   for (; hdr != last_hdr; ++hdr) {
 465     if (hdr->p_type == PT_TLS && info->dlpi_tls_modid == 1) {
 466       *(uptr*)data = hdr->p_memsz;
 467       break;
 468     }
 469   }
 470   return 0;
 471 }
 472 #endif  // SANITIZER_NETBSD
 473
 474 #if SANITIZER_ANDROID
 475 // Bionic provides this API since S.
 476 extern "C" SANITIZER_WEAK_ATTRIBUTE void __libc_get_static_tls_bounds(void **,
 477                                                                       void **);
 478 #endif
 479
 480 #if !SANITIZER_GO
 481 static void GetTls(uptr *addr, uptr *size) {
 482 #if SANITIZER_ANDROID
 483   if (&__libc_get_static_tls_bounds) {
 484     void *start_addr;
 485     void *end_addr;
 486     __libc_get_static_tls_bounds(&start_addr, &end_addr);
 487     *addr = reinterpret_cast<uptr>(start_addr);
 488     *size =
 489         reinterpret_cast<uptr>(end_addr) - reinterpret_cast<uptr>(start_addr);
 490   } else {
 491     *addr = 0;
 492     *size = 0;
 493   }
 494 #elif SANITIZER_GLIBC && defined(__x86_64__)
 495   // For aarch64 and x86-64, use an O(1) approach which requires relatively
 496   // precise ThreadDescriptorSize. g_tls_size was initialized in InitTlsSize.
 497 #  if SANITIZER_X32
 498   asm("mov %%fs:8,%0" : "=r"(*addr));
 499 #  else
 500   asm("mov %%fs:16,%0" : "=r"(*addr));
 501 #  endif
 502   *size = g_tls_size;
 503   *addr -= *size;
 504   *addr += ThreadDescriptorSize();
 505 #elif SANITIZER_GLIBC && defined(__aarch64__)
 506   *addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
 507           ThreadDescriptorSize();
 508   *size = g_tls_size + ThreadDescriptorSize();
 509 #elif SANITIZER_GLIBC && defined(__loongarch__)
 510 #  ifdef __clang__
 511   *addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
 512           ThreadDescriptorSize();
 513 #  else
 514   asm("or %0,$tp,$zero" : "=r"(*addr));
 515   *addr -= ThreadDescriptorSize();
 516 #  endif
 517   *size = g_tls_size + ThreadDescriptorSize();
 518 #elif SANITIZER_GLIBC && defined(__powerpc64__)
 519   // Workaround for glibc<2.25(?). 2.27 is known to not need this.
 520   uptr tp;
 521   asm("addi %0,13,-0x7000" : "=r"(tp));
 522   const uptr pre_tcb_size = TlsPreTcbSize();
 523   *addr = tp - pre_tcb_size;
 524   *size = g_tls_size + pre_tcb_size;
 525 #elif SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_SOLARIS
 526   uptr align;
 527   GetStaticTlsBoundary(addr, size, &align);
 528 #if defined(__x86_64__) || defined(__i386__) || defined(__s390__) || \
 529     defined(__sparc__)
 530   if (SANITIZER_GLIBC) {
 531 #if defined(__x86_64__) || defined(__i386__)
 532     align = Max<uptr>(align, 64);
 533 #else
 534     align = Max<uptr>(align, 16);
 535 #endif
 536   }
 537   const uptr tp = RoundUpTo(*addr + *size, align);
 538
 539   // lsan requires the range to additionally cover the static TLS surplus
 540   // (elf/dl-tls.c defines 1664). Otherwise there may be false positives for
 541   // allocations only referenced by tls in dynamically loaded modules.
 542   if (SANITIZER_GLIBC)
 543     *size += 1644;
 544   else if (SANITIZER_FREEBSD)
 545     *size += 128;  // RTLD_STATIC_TLS_EXTRA
 546
 547   // Extend the range to include the thread control block. On glibc, lsan needs
 548   // the range to include pthread::{specific_1stblock,specific} so that
 549   // allocations only referenced by pthread_setspecific can be scanned. This may
 550   // underestimate by at most TLS_TCB_ALIGN-1 bytes but it should be fine
 551   // because the number of bytes after pthread::specific is larger.
 552   *addr = tp - RoundUpTo(*size, align);
 553   *size = tp - *addr + ThreadDescriptorSize();
 554 #else
 555   if (SANITIZER_GLIBC)
 556     *size += 1664;
 557   else if (SANITIZER_FREEBSD)
 558     *size += 128;  // RTLD_STATIC_TLS_EXTRA
 559 #if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64
 560   const uptr pre_tcb_size = TlsPreTcbSize();
 561   *addr -= pre_tcb_size;
 562   *size += pre_tcb_size;
 563 #else
 564   // arm and aarch64 reserve two words at TP, so this underestimates the range.
 565   // However, this is sufficient for the purpose of finding the pointers to
 566   // thread-specific data keys.
 567   const uptr tcb_size = ThreadDescriptorSize();
 568   *addr -= tcb_size;
 569   *size += tcb_size;
 570 #endif
 571 #endif
 572 #elif SANITIZER_NETBSD
 573   struct tls_tcb * const tcb = ThreadSelfTlsTcb();
 574   *addr = 0;
 575   *size = 0;
 576   if (tcb != 0) {
 577     // Find size (p_memsz) of dlpi_tls_modid 1 (TLS block of the main program).
 578     // ld.elf_so hardcodes the index 1.
 579     dl_iterate_phdr(GetSizeFromHdr, size);
 580
 581     if (*size != 0) {
 582       // The block has been found and tcb_dtv[1] contains the base address
 583       *addr = (uptr)tcb->tcb_dtv[1];
 584     }
 585   }
 586 #else
 587 #error "Unknown OS"
 588 #endif
 589 }
 590 #endif
 591
 592 #if !SANITIZER_GO
 593 uptr GetTlsSize() {
 594 #if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
 595     SANITIZER_SOLARIS
 596   uptr addr, size;
 597   GetTls(&addr, &size);
 598   return size;
 599 #else
 600   return 0;
 601 #endif
 602 }
 603 #endif
 604
 605 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
 606                           uptr *tls_addr, uptr *tls_size) {
 607 #if SANITIZER_GO
 608   // Stub implementation for Go.
 609   *stk_addr = *stk_size = *tls_addr = *tls_size = 0;
 610 #else
 611   GetTls(tls_addr, tls_size);
 612
 613   uptr stack_top, stack_bottom;
 614   GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
 615   *stk_addr = stack_bottom;
 616   *stk_size = stack_top - stack_bottom;
 617
 618   if (!main) {
 619     // If stack and tls intersect, make them non-intersecting.
 620     if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
 621       if (*stk_addr + *stk_size < *tls_addr + *tls_size)
 622         *tls_size = *stk_addr + *stk_size - *tls_addr;
 623       *stk_size = *tls_addr - *stk_addr;
 624     }
 625   }
 626 #endif
 627 }
 628
 629 #if !SANITIZER_FREEBSD
 630 typedef ElfW(Phdr) Elf_Phdr;
 631 #elif SANITIZER_WORDSIZE == 32 && __FreeBSD_version <= 902001  // v9.2
 632 #define Elf_Phdr XElf32_Phdr
 633 #define dl_phdr_info xdl_phdr_info
 634 #define dl_iterate_phdr(c, b) xdl_iterate_phdr((c), (b))
 635 #endif  // !SANITIZER_FREEBSD
 636
 637 struct DlIteratePhdrData {
 638   InternalMmapVectorNoCtor<LoadedModule> *modules;
 639   bool first;
 640 };
 641
 642 static int AddModuleSegments(const char *module_name, dl_phdr_info *info,
 643                              InternalMmapVectorNoCtor<LoadedModule> *modules) {
 644   if (module_name[0] == '\0')
 645     return 0;
 646   LoadedModule cur_module;
 647   cur_module.set(module_name, info->dlpi_addr);
 648   for (int i = 0; i < (int)info->dlpi_phnum; i++) {
 649     const Elf_Phdr *phdr = &info->dlpi_phdr[i];
 650     if (phdr->p_type == PT_LOAD) {
 651       uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
 652       uptr cur_end = cur_beg + phdr->p_memsz;
 653       bool executable = phdr->p_flags & PF_X;
 654       bool writable = phdr->p_flags & PF_W;
 655       cur_module.addAddressRange(cur_beg, cur_end, executable,
 656                                  writable);
 657     } else if (phdr->p_type == PT_NOTE) {
 658 #  ifdef NT_GNU_BUILD_ID
 659       uptr off = 0;
 660       while (off + sizeof(ElfW(Nhdr)) < phdr->p_memsz) {
 661         auto *nhdr = reinterpret_cast<const ElfW(Nhdr) *>(info->dlpi_addr +
 662                                                           phdr->p_vaddr + off);
 663         constexpr auto kGnuNamesz = 4;  // "GNU" with NUL-byte.
 664         static_assert(kGnuNamesz % 4 == 0, "kGnuNameSize is aligned to 4.");
 665         if (nhdr->n_type == NT_GNU_BUILD_ID && nhdr->n_namesz == kGnuNamesz) {
 666           if (off + sizeof(ElfW(Nhdr)) + nhdr->n_namesz + nhdr->n_descsz >
 667               phdr->p_memsz) {
 668             // Something is very wrong, bail out instead of reading potentially
 669             // arbitrary memory.
 670             break;
 671           }
 672           const char *name =
 673               reinterpret_cast<const char *>(nhdr) + sizeof(*nhdr);
 674           if (internal_memcmp(name, "GNU", 3) == 0) {
 675             const char *value = reinterpret_cast<const char *>(nhdr) +
 676                                 sizeof(*nhdr) + kGnuNamesz;
 677             cur_module.setUuid(value, nhdr->n_descsz);
 678             break;
 679           }
 680         }
 681         off += sizeof(*nhdr) + RoundUpTo(nhdr->n_namesz, 4) +
 682                RoundUpTo(nhdr->n_descsz, 4);
 683       }
 684 #  endif
 685     }
 686   }
 687   modules->push_back(cur_module);
 688   return 0;
 689 }
 690
 691 static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
 692   DlIteratePhdrData *data = (DlIteratePhdrData *)arg;
 693   if (data->first) {
 694     InternalMmapVector<char> module_name(kMaxPathLength);
 695     data->first = false;
 696     // First module is the binary itself.
 697     ReadBinaryNameCached(module_name.data(), module_name.size());
 698     return AddModuleSegments(module_name.data(), info, data->modules);
 699   }
 700
 701   if (info->dlpi_name)
 702     return AddModuleSegments(info->dlpi_name, info, data->modules);
 703
 704   return 0;
 705 }
 706
 707 #if SANITIZER_ANDROID && __ANDROID_API__ < 21
 708 extern "C" __attribute__((weak)) int dl_iterate_phdr(
 709     int (*)(struct dl_phdr_info *, size_t, void *), void *);
 710 #endif
 711
 712 static bool requiresProcmaps() {
 713 #if SANITIZER_ANDROID && __ANDROID_API__ <= 22
 714   // Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken.
 715   // The runtime check allows the same library to work with
 716   // both K and L (and future) Android releases.
 717   return AndroidGetApiLevel() <= ANDROID_LOLLIPOP_MR1;
 718 #else
 719   return false;
 720 #endif
 721 }
 722
 723 static void procmapsInit(InternalMmapVectorNoCtor<LoadedModule> *modules) {
 724   MemoryMappingLayout memory_mapping(/*cache_enabled*/true);
 725   memory_mapping.DumpListOfModules(modules);
 726 }
 727
 728 void ListOfModules::init() {
 729   clearOrInit();
 730   if (requiresProcmaps()) {
 731     procmapsInit(&modules_);
 732   } else {
 733     DlIteratePhdrData data = {&modules_, true};
 734     dl_iterate_phdr(dl_iterate_phdr_cb, &data);
 735   }
 736 }
 737
 738 // When a custom loader is used, dl_iterate_phdr may not contain the full
 739 // list of modules. Allow callers to fall back to using procmaps.
 740 void ListOfModules::fallbackInit() {
 741   if (!requiresProcmaps()) {
 742     clearOrInit();
 743     procmapsInit(&modules_);
 744   } else {
 745     clear();
 746   }
 747 }
 748
 749 // getrusage does not give us the current RSS, only the max RSS.
 750 // Still, this is better than nothing if /proc/self/statm is not available
 751 // for some reason, e.g. due to a sandbox.
 752 static uptr GetRSSFromGetrusage() {
 753   struct rusage usage;
 754   if (getrusage(RUSAGE_SELF, &usage))  // Failed, probably due to a sandbox.
 755     return 0;
 756   return usage.ru_maxrss << 10;  // ru_maxrss is in Kb.
 757 }
 758
 759 uptr GetRSS() {
 760   if (!common_flags()->can_use_proc_maps_statm)
 761     return GetRSSFromGetrusage();
 762   fd_t fd = OpenFile("/proc/self/statm", RdOnly);
 763   if (fd == kInvalidFd)
 764     return GetRSSFromGetrusage();
 765   char buf[64];
 766   uptr len = internal_read(fd, buf, sizeof(buf) - 1);
 767   internal_close(fd);
 768   if ((sptr)len <= 0)
 769     return 0;
 770   buf[len] = 0;
 771   // The format of the file is:
 772   // 1084 89 69 11 0 79 0
 773   // We need the second number which is RSS in pages.
 774   char *pos = buf;
 775   // Skip the first number.
 776   while (*pos >= '0' && *pos <= '9')
 777     pos++;
 778   // Skip whitespaces.
 779   while (!(*pos >= '0' && *pos <= '9') && *pos != 0)
 780     pos++;
 781   // Read the number.
 782   uptr rss = 0;
 783   while (*pos >= '0' && *pos <= '9')
 784     rss = rss * 10 + *pos++ - '0';
 785   return rss * GetPageSizeCached();
 786 }
 787
 788 // sysconf(_SC_NPROCESSORS_{CONF,ONLN}) cannot be used on most platforms as
 789 // they allocate memory.
 790 u32 GetNumberOfCPUs() {
 791 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
 792   u32 ncpu;
 793   int req[2];
 794   uptr len = sizeof(ncpu);
 795   req[0] = CTL_HW;
 796   req[1] = HW_NCPU;
 797   CHECK_EQ(internal_sysctl(req, 2, &ncpu, &len, NULL, 0), 0);
 798   return ncpu;
 799 #elif SANITIZER_ANDROID && !defined(CPU_COUNT) && !defined(__aarch64__)
 800   // Fall back to /sys/devices/system/cpu on Android when cpu_set_t doesn't
 801   // exist in sched.h. That is the case for toolchains generated with older
 802   // NDKs.
 803   // This code doesn't work on AArch64 because internal_getdents makes use of
 804   // the 64bit getdents syscall, but cpu_set_t seems to always exist on AArch64.
 805   uptr fd = internal_open("/sys/devices/system/cpu", O_RDONLY | O_DIRECTORY);
 806   if (internal_iserror(fd))
 807     return 0;
 808   InternalMmapVector<u8> buffer(4096);
 809   uptr bytes_read = buffer.size();
 810   uptr n_cpus = 0;
 811   u8 *d_type;
 812   struct linux_dirent *entry = (struct linux_dirent *)&buffer[bytes_read];
 813   while (true) {
 814     if ((u8 *)entry >= &buffer[bytes_read]) {
 815       bytes_read = internal_getdents(fd, (struct linux_dirent *)buffer.data(),
 816                                      buffer.size());
 817       if (internal_iserror(bytes_read) || !bytes_read)
 818         break;
 819       entry = (struct linux_dirent *)buffer.data();
 820     }
 821     d_type = (u8 *)entry + entry->d_reclen - 1;
 822     if (d_type >= &buffer[bytes_read] ||
 823         (u8 *)&entry->d_name[3] >= &buffer[bytes_read])
 824       break;
 825     if (entry->d_ino != 0 && *d_type == DT_DIR) {
 826       if (entry->d_name[0] == 'c' && entry->d_name[1] == 'p' &&
 827           entry->d_name[2] == 'u' &&
 828           entry->d_name[3] >= '0' && entry->d_name[3] <= '9')
 829         n_cpus++;
 830     }
 831     entry = (struct linux_dirent *)(((u8 *)entry) + entry->d_reclen);
 832   }
 833   internal_close(fd);
 834   return n_cpus;
 835 #elif SANITIZER_SOLARIS
 836   return sysconf(_SC_NPROCESSORS_ONLN);
 837 #else
 838 #if defined(CPU_COUNT)
 839   cpu_set_t CPUs;
 840   CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
 841   return CPU_COUNT(&CPUs);
 842 #else
 843   return 1;
 844 #endif
 845 #endif
 846 }
 847
 848 #if SANITIZER_LINUX
 849
 850 #if SANITIZER_ANDROID
 851 static atomic_uint8_t android_log_initialized;
 852
 853 void AndroidLogInit() {
 854   openlog(GetProcessName(), 0, LOG_USER);
 855   atomic_store(&android_log_initialized, 1, memory_order_release);
 856 }
 857
 858 static bool ShouldLogAfterPrintf() {
 859   return atomic_load(&android_log_initialized, memory_order_acquire);
 860 }
 861
 862 extern "C" SANITIZER_WEAK_ATTRIBUTE
 863 int async_safe_write_log(int pri, const char* tag, const char* msg);
 864 extern "C" SANITIZER_WEAK_ATTRIBUTE
 865 int __android_log_write(int prio, const char* tag, const char* msg);
 866
 867 // ANDROID_LOG_INFO is 4, but can't be resolved at runtime.
 868 #define SANITIZER_ANDROID_LOG_INFO 4
 869
 870 // async_safe_write_log is a new public version of __libc_write_log that is
 871 // used behind syslog. It is preferable to syslog as it will not do any dynamic
 872 // memory allocation or formatting.
 873 // If the function is not available, syslog is preferred for L+ (it was broken
 874 // pre-L) as __android_log_write triggers a racey behavior with the strncpy
 875 // interceptor. Fallback to __android_log_write pre-L.
 876 void WriteOneLineToSyslog(const char *s) {
 877   if (&async_safe_write_log) {
 878     async_safe_write_log(SANITIZER_ANDROID_LOG_INFO, GetProcessName(), s);
 879   } else if (AndroidGetApiLevel() > ANDROID_KITKAT) {
 880     syslog(LOG_INFO, "%s", s);
 881   } else {
 882     CHECK(&__android_log_write);
 883     __android_log_write(SANITIZER_ANDROID_LOG_INFO, nullptr, s);
 884   }
 885 }
 886
 887 extern "C" SANITIZER_WEAK_ATTRIBUTE
 888 void android_set_abort_message(const char *);
 889
 890 void SetAbortMessage(const char *str) {
 891   if (&android_set_abort_message)
 892     android_set_abort_message(str);
 893 }
 894 #else
 895 void AndroidLogInit() {}
 896
 897 static bool ShouldLogAfterPrintf() { return true; }
 898
 899 void WriteOneLineToSyslog(const char *s) { syslog(LOG_INFO, "%s", s); }
 900
 901 void SetAbortMessage(const char *str) {}
 902 #endif  // SANITIZER_ANDROID
 903
 904 void LogMessageOnPrintf(const char *str) {
 905   if (common_flags()->log_to_syslog && ShouldLogAfterPrintf())
 906     WriteToSyslog(str);
 907 }
 908
 909 #endif  // SANITIZER_LINUX
 910
 911 #if SANITIZER_GLIBC && !SANITIZER_GO
 912 // glibc crashes when using clock_gettime from a preinit_array function as the
 913 // vDSO function pointers haven't been initialized yet. __progname is
 914 // initialized after the vDSO function pointers, so if it exists, is not null
 915 // and is not empty, we can use clock_gettime.
 916 extern "C" SANITIZER_WEAK_ATTRIBUTE char *__progname;
 917 inline bool CanUseVDSO() { return &__progname && __progname && *__progname; }
 918
 919 // MonotonicNanoTime is a timing function that can leverage the vDSO by calling
 920 // clock_gettime. real_clock_gettime only exists if clock_gettime is
 921 // intercepted, so define it weakly and use it if available.
 922 extern "C" SANITIZER_WEAK_ATTRIBUTE
 923 int real_clock_gettime(u32 clk_id, void *tp);
 924 u64 MonotonicNanoTime() {
 925   timespec ts;
 926   if (CanUseVDSO()) {
 927     if (&real_clock_gettime)
 928       real_clock_gettime(CLOCK_MONOTONIC, &ts);
 929     else
 930       clock_gettime(CLOCK_MONOTONIC, &ts);
 931   } else {
 932     internal_clock_gettime(CLOCK_MONOTONIC, &ts);
 933   }
 934   return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
 935 }
 936 #else
 937 // Non-glibc & Go always use the regular function.
 938 u64 MonotonicNanoTime() {
 939   timespec ts;
 940   clock_gettime(CLOCK_MONOTONIC, &ts);
 941   return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
 942 }
 943 #endif  // SANITIZER_GLIBC && !SANITIZER_GO
 944
 945 void ReExec() {
 946   const char *pathname = "/proc/self/exe";
 947
 948 #if SANITIZER_NETBSD
 949   static const int name[] = {
 950       CTL_KERN,
 951       KERN_PROC_ARGS,
 952       -1,
 953       KERN_PROC_PATHNAME,
 954   };
 955   char path[400];
 956   uptr len;
 957
 958   len = sizeof(path);
 959   if (internal_sysctl(name, ARRAY_SIZE(name), path, &len, NULL, 0) != -1)
 960     pathname = path;
 961 #elif SANITIZER_SOLARIS
 962   pathname = getexecname();
 963   CHECK_NE(pathname, NULL);
 964 #elif SANITIZER_USE_GETAUXVAL
 965   // Calling execve with /proc/self/exe sets that as $EXEC_ORIGIN. Binaries that
 966   // rely on that will fail to load shared libraries. Query AT_EXECFN instead.
 967   pathname = reinterpret_cast<const char *>(getauxval(AT_EXECFN));
 968 #endif
 969
 970   uptr rv = internal_execve(pathname, GetArgv(), GetEnviron());
 971   int rverrno;
 972   CHECK_EQ(internal_iserror(rv, &rverrno), true);
 973   Printf("execve failed, errno %d\n", rverrno);
 974   Die();
 975 }
 976
 977 void UnmapFromTo(uptr from, uptr to) {
 978   if (to == from)
 979     return;
 980   CHECK(to >= from);
 981   uptr res = internal_munmap(reinterpret_cast<void *>(from), to - from);
 982   if (UNLIKELY(internal_iserror(res))) {
 983     Report("ERROR: %s failed to unmap 0x%zx (%zd) bytes at address %p\n",
 984            SanitizerToolName, to - from, to - from, (void *)from);
 985     CHECK("unable to unmap" && 0);
 986   }
 987 }
 988
 989 uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
 990                       uptr min_shadow_base_alignment,
 991                       UNUSED uptr &high_mem_end) {
 992   const uptr granularity = GetMmapGranularity();
 993   const uptr alignment =
 994       Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
 995   const uptr left_padding =
 996       Max<uptr>(granularity, 1ULL << min_shadow_base_alignment);
 997
 998   const uptr shadow_size = RoundUpTo(shadow_size_bytes, granularity);
 999   const uptr map_size = shadow_size + left_padding + alignment;
1000
1001   const uptr map_start = (uptr)MmapNoAccess(map_size);
1002   CHECK_NE(map_start, ~(uptr)0);
1003
1004   const uptr shadow_start = RoundUpTo(map_start + left_padding, alignment);
1005
1006   UnmapFromTo(map_start, shadow_start - left_padding);
1007   UnmapFromTo(shadow_start + shadow_size, map_start + map_size);
1008
1009   return shadow_start;
1010 }
1011
1012 static uptr MmapSharedNoReserve(uptr addr, uptr size) {
1013   return internal_mmap(
1014       reinterpret_cast<void *>(addr), size, PROT_READ | PROT_WRITE,
1015       MAP_FIXED | MAP_SHARED | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
1016 }
1017
1018 static uptr MremapCreateAlias(uptr base_addr, uptr alias_addr,
1019                               uptr alias_size) {
1020 #if SANITIZER_LINUX
1021   return internal_mremap(reinterpret_cast<void *>(base_addr), 0, alias_size,
1022                          MREMAP_MAYMOVE | MREMAP_FIXED,
1023                          reinterpret_cast<void *>(alias_addr));
1024 #else
1025   CHECK(false && "mremap is not supported outside of Linux");
1026   return 0;
1027 #endif
1028 }
1029
1030 static void CreateAliases(uptr start_addr, uptr alias_size, uptr num_aliases) {
1031   uptr total_size = alias_size * num_aliases;
1032   uptr mapped = MmapSharedNoReserve(start_addr, total_size);
1033   CHECK_EQ(mapped, start_addr);
1034
1035   for (uptr i = 1; i < num_aliases; ++i) {
1036     uptr alias_addr = start_addr + i * alias_size;
1037     CHECK_EQ(MremapCreateAlias(start_addr, alias_addr, alias_size), alias_addr);
1038   }
1039 }
1040
1041 uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size,
1042                                 uptr num_aliases, uptr ring_buffer_size) {
1043   CHECK_EQ(alias_size & (alias_size - 1), 0);
1044   CHECK_EQ(num_aliases & (num_aliases - 1), 0);
1045   CHECK_EQ(ring_buffer_size & (ring_buffer_size - 1), 0);
1046
1047   const uptr granularity = GetMmapGranularity();
1048   shadow_size = RoundUpTo(shadow_size, granularity);
1049   CHECK_EQ(shadow_size & (shadow_size - 1), 0);
1050
1051   const uptr alias_region_size = alias_size * num_aliases;
1052   const uptr alignment =
1053       2 * Max(Max(shadow_size, alias_region_size), ring_buffer_size);
1054   const uptr left_padding = ring_buffer_size;
1055
1056   const uptr right_size = alignment;
1057   const uptr map_size = left_padding + 2 * alignment;
1058
1059   const uptr map_start = reinterpret_cast<uptr>(MmapNoAccess(map_size));
1060   CHECK_NE(map_start, static_cast<uptr>(-1));
1061   const uptr right_start = RoundUpTo(map_start + left_padding, alignment);
1062
1063   UnmapFromTo(map_start, right_start - left_padding);
1064   UnmapFromTo(right_start + right_size, map_start + map_size);
1065
1066   CreateAliases(right_start + right_size / 2, alias_size, num_aliases);
1067
1068   return right_start;
1069 }
1070
1071 void InitializePlatformCommonFlags(CommonFlags *cf) {
1072 #if SANITIZER_ANDROID
1073   if (&__libc_get_static_tls_bounds == nullptr)
1074     cf->detect_leaks = false;
1075 #endif
1076 }
1077
1078 } // namespace __sanitizer
1079
1080 #endif