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_OPENBSD || 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
  31 #include <dlfcn.h>  // for dlsym()
  32 #include <link.h>
  33 #include <pthread.h>
  34 #include <signal.h>
  35 #include <sys/resource.h>
  36 #include <syslog.h>
  37
  38 #if !defined(ElfW)
  39 #define ElfW(type) Elf_##type
  40 #endif
  41
  42 #if SANITIZER_FREEBSD
  43 #include <pthread_np.h>
  44 #include <osreldate.h>
  45 #include <sys/sysctl.h>
  46 #define pthread_getattr_np pthread_attr_get_np
  47 #endif
  48
  49 #if SANITIZER_OPENBSD
  50 #include <pthread_np.h>
  51 #include <sys/sysctl.h>
  52 #endif
  53
  54 #if SANITIZER_NETBSD
  55 #include <sys/sysctl.h>
  56 #include <sys/tls.h>
  57 #include <lwp.h>
  58 #endif
  59
  60 #if SANITIZER_SOLARIS
  61 #include <stdlib.h>
  62 #include <thread.h>
  63 #endif
  64
  65 #if SANITIZER_ANDROID
  66 #include <android/api-level.h>
  67 #if !defined(CPU_COUNT) && !defined(__aarch64__)
  68 #include <dirent.h>
  69 #include <fcntl.h>
  70 struct __sanitizer::linux_dirent {
  71   long           d_ino;
  72   off_t          d_off;
  73   unsigned short d_reclen;
  74   char           d_name[];
  75 };
  76 #endif
  77 #endif
  78
  79 #if !SANITIZER_ANDROID
  80 #include <elf.h>
  81 #include <unistd.h>
  82 #endif
  83
  84 namespace __sanitizer {
  85
  86 SANITIZER_WEAK_ATTRIBUTE int
  87 real_sigaction(int signum, const void *act, void *oldact);
  88
  89 int internal_sigaction(int signum, const void *act, void *oldact) {
  90 #if !SANITIZER_GO
  91   if (&real_sigaction)
  92     return real_sigaction(signum, act, oldact);
  93 #endif
  94   return sigaction(signum, (const struct sigaction *)act,
  95                    (struct sigaction *)oldact);
  96 }
  97
  98 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
  99                                 uptr *stack_bottom) {
 100   CHECK(stack_top);
 101   CHECK(stack_bottom);
 102   if (at_initialization) {
 103     // This is the main thread. Libpthread may not be initialized yet.
 104     struct rlimit rl;
 105     CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
 106
 107     // Find the mapping that contains a stack variable.
 108     MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 109     if (proc_maps.Error()) {
 110       *stack_top = *stack_bottom = 0;
 111       return;
 112     }
 113     MemoryMappedSegment segment;
 114     uptr prev_end = 0;
 115     while (proc_maps.Next(&segment)) {
 116       if ((uptr)&rl < segment.end) break;
 117       prev_end = segment.end;
 118     }
 119     CHECK((uptr)&rl >= segment.start && (uptr)&rl < segment.end);
 120
 121     // Get stacksize from rlimit, but clip it so that it does not overlap
 122     // with other mappings.
 123     uptr stacksize = rl.rlim_cur;
 124     if (stacksize > segment.end - prev_end) stacksize = segment.end - prev_end;
 125     // When running with unlimited stack size, we still want to set some limit.
 126     // The unlimited stack size is caused by 'ulimit -s unlimited'.
 127     // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
 128     if (stacksize > kMaxThreadStackSize)
 129       stacksize = kMaxThreadStackSize;
 130     *stack_top = segment.end;
 131     *stack_bottom = segment.end - stacksize;
 132     return;
 133   }
 134   uptr stacksize = 0;
 135   void *stackaddr = nullptr;
 136 #if SANITIZER_SOLARIS
 137   stack_t ss;
 138   CHECK_EQ(thr_stksegment(&ss), 0);
 139   stacksize = ss.ss_size;
 140   stackaddr = (char *)ss.ss_sp - stacksize;
 141 #elif SANITIZER_OPENBSD
 142   stack_t sattr;
 143   CHECK_EQ(pthread_stackseg_np(pthread_self(), &sattr), 0);
 144   stackaddr = sattr.ss_sp;
 145   stacksize = sattr.ss_size;
 146 #else  // !SANITIZER_SOLARIS
 147   pthread_attr_t attr;
 148   pthread_attr_init(&attr);
 149   CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
 150   my_pthread_attr_getstack(&attr, &stackaddr, &stacksize);
 151   pthread_attr_destroy(&attr);
 152 #endif // SANITIZER_SOLARIS
 153
 154   *stack_top = (uptr)stackaddr + stacksize;
 155   *stack_bottom = (uptr)stackaddr;
 156 }
 157
 158 #if !SANITIZER_GO
 159 bool SetEnv(const char *name, const char *value) {
 160   void *f = dlsym(RTLD_NEXT, "setenv");
 161   if (!f)
 162     return false;
 163   typedef int(*setenv_ft)(const char *name, const char *value, int overwrite);
 164   setenv_ft setenv_f;
 165   CHECK_EQ(sizeof(setenv_f), sizeof(f));
 166   internal_memcpy(&setenv_f, &f, sizeof(f));
 167   return setenv_f(name, value, 1) == 0;
 168 }
 169 #endif
 170
 171 __attribute__((unused)) static bool GetLibcVersion(int *major, int *minor,
 172                                                    int *patch) {
 173 #ifdef _CS_GNU_LIBC_VERSION
 174   char buf[64];
 175   uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
 176   if (len >= sizeof(buf))
 177     return false;
 178   buf[len] = 0;
 179   static const char kGLibC[] = "glibc ";
 180   if (internal_strncmp(buf, kGLibC, sizeof(kGLibC) - 1) != 0)
 181     return false;
 182   const char *p = buf + sizeof(kGLibC) - 1;
 183   *major = internal_simple_strtoll(p, &p, 10);
 184   *minor = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
 185   *patch = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
 186   return true;
 187 #else
 188   return false;
 189 #endif
 190 }
 191
 192 #if !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO &&               \
 193     !SANITIZER_NETBSD && !SANITIZER_OPENBSD && !SANITIZER_SOLARIS
 194 static uptr g_tls_size;
 195
 196 #ifdef __i386__
 197 # define CHECK_GET_TLS_STATIC_INFO_VERSION (!__GLIBC_PREREQ(2, 27))
 198 #else
 199 # define CHECK_GET_TLS_STATIC_INFO_VERSION 0
 200 #endif
 201
 202 #if CHECK_GET_TLS_STATIC_INFO_VERSION
 203 # define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
 204 #else
 205 # define DL_INTERNAL_FUNCTION
 206 #endif
 207
 208 namespace {
 209 struct GetTlsStaticInfoCall {
 210   typedef void (*get_tls_func)(size_t*, size_t*);
 211 };
 212 struct GetTlsStaticInfoRegparmCall {
 213   typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION;
 214 };
 215
 216 template <typename T>
 217 void CallGetTls(void* ptr, size_t* size, size_t* align) {
 218   typename T::get_tls_func get_tls;
 219   CHECK_EQ(sizeof(get_tls), sizeof(ptr));
 220   internal_memcpy(&get_tls, &ptr, sizeof(ptr));
 221   CHECK_NE(get_tls, 0);
 222   get_tls(size, align);
 223 }
 224
 225 bool CmpLibcVersion(int major, int minor, int patch) {
 226   int ma;
 227   int mi;
 228   int pa;
 229   if (!GetLibcVersion(&ma, &mi, &pa))
 230     return false;
 231   if (ma > major)
 232     return true;
 233   if (ma < major)
 234     return false;
 235   if (mi > minor)
 236     return true;
 237   if (mi < minor)
 238     return false;
 239   return pa >= patch;
 240 }
 241
 242 }  // namespace
 243
 244 void InitTlsSize() {
 245   // all current supported platforms have 16 bytes stack alignment
 246   const size_t kStackAlign = 16;
 247   void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
 248   size_t tls_size = 0;
 249   size_t tls_align = 0;
 250   // On i?86, _dl_get_tls_static_info used to be internal_function, i.e.
 251   // __attribute__((regparm(3), stdcall)) before glibc 2.27 and is normal
 252   // function in 2.27 and later.
 253   if (CHECK_GET_TLS_STATIC_INFO_VERSION && !CmpLibcVersion(2, 27, 0))
 254     CallGetTls<GetTlsStaticInfoRegparmCall>(get_tls_static_info_ptr,
 255                                             &tls_size, &tls_align);
 256   else
 257     CallGetTls<GetTlsStaticInfoCall>(get_tls_static_info_ptr,
 258                                      &tls_size, &tls_align);
 259   if (tls_align < kStackAlign)
 260     tls_align = kStackAlign;
 261   g_tls_size = RoundUpTo(tls_size, tls_align);
 262 }
 263 #else
 264 void InitTlsSize() { }
 265 #endif  // !SANITIZER_FREEBSD && !SANITIZER_ANDROID && !SANITIZER_GO &&
 266         // !SANITIZER_NETBSD && !SANITIZER_SOLARIS
 267
 268 #if (defined(__x86_64__) || defined(__i386__) || defined(__mips__) ||          \
 269      defined(__aarch64__) || defined(__powerpc64__) || defined(__s390__) ||    \
 270      defined(__arm__)) &&                                                      \
 271     SANITIZER_LINUX && !SANITIZER_ANDROID
 272 // sizeof(struct pthread) from glibc.
 273 static atomic_uintptr_t thread_descriptor_size;
 274
 275 uptr ThreadDescriptorSize() {
 276   uptr val = atomic_load_relaxed(&thread_descriptor_size);
 277   if (val)
 278     return val;
 279 #if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
 280   int major;
 281   int minor;
 282   int patch;
 283   if (GetLibcVersion(&major, &minor, &patch) && major == 2) {
 284     /* sizeof(struct pthread) values from various glibc versions.  */
 285     if (SANITIZER_X32)
 286       val = 1728; // Assume only one particular version for x32.
 287     // For ARM sizeof(struct pthread) changed in Glibc 2.23.
 288     else if (SANITIZER_ARM)
 289       val = minor <= 22 ? 1120 : 1216;
 290     else if (minor <= 3)
 291       val = FIRST_32_SECOND_64(1104, 1696);
 292     else if (minor == 4)
 293       val = FIRST_32_SECOND_64(1120, 1728);
 294     else if (minor == 5)
 295       val = FIRST_32_SECOND_64(1136, 1728);
 296     else if (minor <= 9)
 297       val = FIRST_32_SECOND_64(1136, 1712);
 298     else if (minor == 10)
 299       val = FIRST_32_SECOND_64(1168, 1776);
 300     else if (minor == 11 || (minor == 12 && patch == 1))
 301       val = FIRST_32_SECOND_64(1168, 2288);
 302     else if (minor <= 14)
 303       val = FIRST_32_SECOND_64(1168, 2304);
 304     else
 305       val = FIRST_32_SECOND_64(1216, 2304);
 306   }
 307 #elif defined(__mips__)
 308   // TODO(sagarthakur): add more values as per different glibc versions.
 309   val = FIRST_32_SECOND_64(1152, 1776);
 310 #elif defined(__aarch64__)
 311   // The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
 312   val = 1776;
 313 #elif defined(__powerpc64__)
 314   val = 1776; // from glibc.ppc64le 2.20-8.fc21
 315 #elif defined(__s390__)
 316   val = FIRST_32_SECOND_64(1152, 1776); // valid for glibc 2.22
 317 #endif
 318   if (val)
 319     atomic_store_relaxed(&thread_descriptor_size, val);
 320   return val;
 321 }
 322
 323 // The offset at which pointer to self is located in the thread descriptor.
 324 const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16);
 325
 326 uptr ThreadSelfOffset() {
 327   return kThreadSelfOffset;
 328 }
 329
 330 #if defined(__mips__) || defined(__powerpc64__)
 331 // TlsPreTcbSize includes size of struct pthread_descr and size of tcb
 332 // head structure. It lies before the static tls blocks.
 333 static uptr TlsPreTcbSize() {
 334 # if defined(__mips__)
 335   const uptr kTcbHead = 16; // sizeof (tcbhead_t)
 336 # elif defined(__powerpc64__)
 337   const uptr kTcbHead = 88; // sizeof (tcbhead_t)
 338 # endif
 339   const uptr kTlsAlign = 16;
 340   const uptr kTlsPreTcbSize =
 341       RoundUpTo(ThreadDescriptorSize() + kTcbHead, kTlsAlign);
 342   return kTlsPreTcbSize;
 343 }
 344 #endif
 345
 346 uptr ThreadSelf() {
 347   uptr descr_addr;
 348 # if defined(__i386__)
 349   asm("mov %%gs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
 350 # elif defined(__x86_64__)
 351   asm("mov %%fs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
 352 # elif defined(__mips__)
 353   // MIPS uses TLS variant I. The thread pointer (in hardware register $29)
 354   // points to the end of the TCB + 0x7000. The pthread_descr structure is
 355   // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
 356   // TCB and the size of pthread_descr.
 357   const uptr kTlsTcbOffset = 0x7000;
 358   uptr thread_pointer;
 359   asm volatile(".set push;\
 360                 .set mips64r2;\
 361                 rdhwr %0,$29;\
 362                 .set pop" : "=r" (thread_pointer));
 363   descr_addr = thread_pointer - kTlsTcbOffset - TlsPreTcbSize();
 364 # elif defined(__aarch64__) || defined(__arm__)
 365   descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
 366                                       ThreadDescriptorSize();
 367 # elif defined(__s390__)
 368   descr_addr = reinterpret_cast<uptr>(__builtin_thread_pointer());
 369 # elif defined(__powerpc64__)
 370   // PPC64LE uses TLS variant I. The thread pointer (in GPR 13)
 371   // points to the end of the TCB + 0x7000. The pthread_descr structure is
 372   // immediately in front of the TCB. TlsPreTcbSize() includes the size of the
 373   // TCB and the size of pthread_descr.
 374   const uptr kTlsTcbOffset = 0x7000;
 375   uptr thread_pointer;
 376   asm("addi %0,13,%1" : "=r"(thread_pointer) : "I"(-kTlsTcbOffset));
 377   descr_addr = thread_pointer - TlsPreTcbSize();
 378 # else
 379 #  error "unsupported CPU arch"
 380 # endif
 381   return descr_addr;
 382 }
 383 #endif  // (x86_64 || i386 || MIPS) && SANITIZER_LINUX
 384
 385 #if SANITIZER_FREEBSD
 386 static void **ThreadSelfSegbase() {
 387   void **segbase = 0;
 388 # if defined(__i386__)
 389   // sysarch(I386_GET_GSBASE, segbase);
 390   __asm __volatile("mov %%gs:0, %0" : "=r" (segbase));
 391 # elif defined(__x86_64__)
 392   // sysarch(AMD64_GET_FSBASE, segbase);
 393   __asm __volatile("movq %%fs:0, %0" : "=r" (segbase));
 394 # else
 395 #  error "unsupported CPU arch"
 396 # endif
 397   return segbase;
 398 }
 399
 400 uptr ThreadSelf() {
 401   return (uptr)ThreadSelfSegbase()[2];
 402 }
 403 #endif  // SANITIZER_FREEBSD
 404
 405 #if SANITIZER_NETBSD
 406 static struct tls_tcb * ThreadSelfTlsTcb() {
 407   return (struct tls_tcb *)_lwp_getprivate();
 408 }
 409
 410 uptr ThreadSelf() {
 411   return (uptr)ThreadSelfTlsTcb()->tcb_pthread;
 412 }
 413
 414 int GetSizeFromHdr(struct dl_phdr_info *info, size_t size, void *data) {
 415   const Elf_Phdr *hdr = info->dlpi_phdr;
 416   const Elf_Phdr *last_hdr = hdr + info->dlpi_phnum;
 417
 418   for (; hdr != last_hdr; ++hdr) {
 419     if (hdr->p_type == PT_TLS && info->dlpi_tls_modid == 1) {
 420       *(uptr*)data = hdr->p_memsz;
 421       break;
 422     }
 423   }
 424   return 0;
 425 }
 426 #endif  // SANITIZER_NETBSD
 427
 428 #if !SANITIZER_GO
 429 static void GetTls(uptr *addr, uptr *size) {
 430 #if SANITIZER_LINUX && !SANITIZER_ANDROID
 431 # if defined(__x86_64__) || defined(__i386__) || defined(__s390__)
 432   *addr = ThreadSelf();
 433   *size = GetTlsSize();
 434   *addr -= *size;
 435   *addr += ThreadDescriptorSize();
 436 # elif defined(__mips__) || defined(__aarch64__) || defined(__powerpc64__) \
 437     || defined(__arm__)
 438   *addr = ThreadSelf();
 439   *size = GetTlsSize();
 440 # else
 441   *addr = 0;
 442   *size = 0;
 443 # endif
 444 #elif SANITIZER_FREEBSD
 445   void** segbase = ThreadSelfSegbase();
 446   *addr = 0;
 447   *size = 0;
 448   if (segbase != 0) {
 449     // tcbalign = 16
 450     // tls_size = round(tls_static_space, tcbalign);
 451     // dtv = segbase[1];
 452     // dtv[2] = segbase - tls_static_space;
 453     void **dtv = (void**) segbase[1];
 454     *addr = (uptr) dtv[2];
 455     *size = (*addr == 0) ? 0 : ((uptr) segbase[0] - (uptr) dtv[2]);
 456   }
 457 #elif SANITIZER_NETBSD
 458   struct tls_tcb * const tcb = ThreadSelfTlsTcb();
 459   *addr = 0;
 460   *size = 0;
 461   if (tcb != 0) {
 462     // Find size (p_memsz) of dlpi_tls_modid 1 (TLS block of the main program).
 463     // ld.elf_so hardcodes the index 1.
 464     dl_iterate_phdr(GetSizeFromHdr, size);
 465
 466     if (*size != 0) {
 467       // The block has been found and tcb_dtv[1] contains the base address
 468       *addr = (uptr)tcb->tcb_dtv[1];
 469     }
 470   }
 471 #elif SANITIZER_OPENBSD
 472   *addr = 0;
 473   *size = 0;
 474 #elif SANITIZER_ANDROID
 475   *addr = 0;
 476   *size = 0;
 477 #elif SANITIZER_SOLARIS
 478   // FIXME
 479   *addr = 0;
 480   *size = 0;
 481 #else
 482 # error "Unknown OS"
 483 #endif
 484 }
 485 #endif
 486
 487 #if !SANITIZER_GO
 488 uptr GetTlsSize() {
 489 #if SANITIZER_FREEBSD || SANITIZER_ANDROID || SANITIZER_NETBSD ||              \
 490     SANITIZER_OPENBSD || SANITIZER_SOLARIS
 491   uptr addr, size;
 492   GetTls(&addr, &size);
 493   return size;
 494 #elif defined(__mips__) || defined(__powerpc64__)
 495   return RoundUpTo(g_tls_size + TlsPreTcbSize(), 16);
 496 #else
 497   return g_tls_size;
 498 #endif
 499 }
 500 #endif
 501
 502 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
 503                           uptr *tls_addr, uptr *tls_size) {
 504 #if SANITIZER_GO
 505   // Stub implementation for Go.
 506   *stk_addr = *stk_size = *tls_addr = *tls_size = 0;
 507 #else
 508   GetTls(tls_addr, tls_size);
 509
 510   uptr stack_top, stack_bottom;
 511   GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
 512   *stk_addr = stack_bottom;
 513   *stk_size = stack_top - stack_bottom;
 514
 515   if (!main) {
 516     // If stack and tls intersect, make them non-intersecting.
 517     if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
 518       CHECK_GT(*tls_addr + *tls_size, *stk_addr);
 519       CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
 520       *stk_size -= *tls_size;
 521       *tls_addr = *stk_addr + *stk_size;
 522     }
 523   }
 524 #endif
 525 }
 526
 527 #if !SANITIZER_FREEBSD && !SANITIZER_OPENBSD
 528 typedef ElfW(Phdr) Elf_Phdr;
 529 #elif SANITIZER_WORDSIZE == 32 && __FreeBSD_version <= 902001 // v9.2
 530 #define Elf_Phdr XElf32_Phdr
 531 #define dl_phdr_info xdl_phdr_info
 532 #define dl_iterate_phdr(c, b) xdl_iterate_phdr((c), (b))
 533 #endif // !SANITIZER_FREEBSD && !SANITIZER_OPENBSD
 534
 535 struct DlIteratePhdrData {
 536   InternalMmapVectorNoCtor<LoadedModule> *modules;
 537   bool first;
 538 };
 539
 540 static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
 541   DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
 542   InternalScopedString module_name(kMaxPathLength);
 543   if (data->first) {
 544     data->first = false;
 545     // First module is the binary itself.
 546     ReadBinaryNameCached(module_name.data(), module_name.size());
 547   } else if (info->dlpi_name) {
 548     module_name.append("%s", info->dlpi_name);
 549   }
 550   if (module_name[0] == '\0')
 551     return 0;
 552   LoadedModule cur_module;
 553   cur_module.set(module_name.data(), info->dlpi_addr);
 554   for (int i = 0; i < (int)info->dlpi_phnum; i++) {
 555     const Elf_Phdr *phdr = &info->dlpi_phdr[i];
 556     if (phdr->p_type == PT_LOAD) {
 557       uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
 558       uptr cur_end = cur_beg + phdr->p_memsz;
 559       bool executable = phdr->p_flags & PF_X;
 560       bool writable = phdr->p_flags & PF_W;
 561       cur_module.addAddressRange(cur_beg, cur_end, executable,
 562                                  writable);
 563     }
 564   }
 565   data->modules->push_back(cur_module);
 566   return 0;
 567 }
 568
 569 #if SANITIZER_ANDROID && __ANDROID_API__ < 21
 570 extern "C" __attribute__((weak)) int dl_iterate_phdr(
 571     int (*)(struct dl_phdr_info *, size_t, void *), void *);
 572 #endif
 573
 574 static bool requiresProcmaps() {
 575 #if SANITIZER_ANDROID && __ANDROID_API__ <= 22
 576   // Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken.
 577   // The runtime check allows the same library to work with
 578   // both K and L (and future) Android releases.
 579   return AndroidGetApiLevel() <= ANDROID_LOLLIPOP_MR1;
 580 #else
 581   return false;
 582 #endif
 583 }
 584
 585 static void procmapsInit(InternalMmapVectorNoCtor<LoadedModule> *modules) {
 586   MemoryMappingLayout memory_mapping(/*cache_enabled*/true);
 587   memory_mapping.DumpListOfModules(modules);
 588 }
 589
 590 void ListOfModules::init() {
 591   clearOrInit();
 592   if (requiresProcmaps()) {
 593     procmapsInit(&modules_);
 594   } else {
 595     DlIteratePhdrData data = {&modules_, true};
 596     dl_iterate_phdr(dl_iterate_phdr_cb, &data);
 597   }
 598 }
 599
 600 // When a custom loader is used, dl_iterate_phdr may not contain the full
 601 // list of modules. Allow callers to fall back to using procmaps.
 602 void ListOfModules::fallbackInit() {
 603   if (!requiresProcmaps()) {
 604     clearOrInit();
 605     procmapsInit(&modules_);
 606   } else {
 607     clear();
 608   }
 609 }
 610
 611 // getrusage does not give us the current RSS, only the max RSS.
 612 // Still, this is better than nothing if /proc/self/statm is not available
 613 // for some reason, e.g. due to a sandbox.
 614 static uptr GetRSSFromGetrusage() {
 615   struct rusage usage;
 616   if (getrusage(RUSAGE_SELF, &usage))  // Failed, probably due to a sandbox.
 617     return 0;
 618   return usage.ru_maxrss << 10;  // ru_maxrss is in Kb.
 619 }
 620
 621 uptr GetRSS() {
 622   if (!common_flags()->can_use_proc_maps_statm)
 623     return GetRSSFromGetrusage();
 624   fd_t fd = OpenFile("/proc/self/statm", RdOnly);
 625   if (fd == kInvalidFd)
 626     return GetRSSFromGetrusage();
 627   char buf[64];
 628   uptr len = internal_read(fd, buf, sizeof(buf) - 1);
 629   internal_close(fd);
 630   if ((sptr)len <= 0)
 631     return 0;
 632   buf[len] = 0;
 633   // The format of the file is:
 634   // 1084 89 69 11 0 79 0
 635   // We need the second number which is RSS in pages.
 636   char *pos = buf;
 637   // Skip the first number.
 638   while (*pos >= '0' && *pos <= '9')
 639     pos++;
 640   // Skip whitespaces.
 641   while (!(*pos >= '0' && *pos <= '9') && *pos != 0)
 642     pos++;
 643   // Read the number.
 644   uptr rss = 0;
 645   while (*pos >= '0' && *pos <= '9')
 646     rss = rss * 10 + *pos++ - '0';
 647   return rss * GetPageSizeCached();
 648 }
 649
 650 // sysconf(_SC_NPROCESSORS_{CONF,ONLN}) cannot be used on most platforms as
 651 // they allocate memory.
 652 u32 GetNumberOfCPUs() {
 653 #if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_OPENBSD
 654   u32 ncpu;
 655   int req[2];
 656   uptr len = sizeof(ncpu);
 657   req[0] = CTL_HW;
 658   req[1] = HW_NCPU;
 659   CHECK_EQ(internal_sysctl(req, 2, &ncpu, &len, NULL, 0), 0);
 660   return ncpu;
 661 #elif SANITIZER_ANDROID && !defined(CPU_COUNT) && !defined(__aarch64__)
 662   // Fall back to /sys/devices/system/cpu on Android when cpu_set_t doesn't
 663   // exist in sched.h. That is the case for toolchains generated with older
 664   // NDKs.
 665   // This code doesn't work on AArch64 because internal_getdents makes use of
 666   // the 64bit getdents syscall, but cpu_set_t seems to always exist on AArch64.
 667   uptr fd = internal_open("/sys/devices/system/cpu", O_RDONLY | O_DIRECTORY);
 668   if (internal_iserror(fd))
 669     return 0;
 670   InternalMmapVector<u8> buffer(4096);
 671   uptr bytes_read = buffer.size();
 672   uptr n_cpus = 0;
 673   u8 *d_type;
 674   struct linux_dirent *entry = (struct linux_dirent *)&buffer[bytes_read];
 675   while (true) {
 676     if ((u8 *)entry >= &buffer[bytes_read]) {
 677       bytes_read = internal_getdents(fd, (struct linux_dirent *)buffer.data(),
 678                                      buffer.size());
 679       if (internal_iserror(bytes_read) || !bytes_read)
 680         break;
 681       entry = (struct linux_dirent *)buffer.data();
 682     }
 683     d_type = (u8 *)entry + entry->d_reclen - 1;
 684     if (d_type >= &buffer[bytes_read] ||
 685         (u8 *)&entry->d_name[3] >= &buffer[bytes_read])
 686       break;
 687     if (entry->d_ino != 0 && *d_type == DT_DIR) {
 688       if (entry->d_name[0] == 'c' && entry->d_name[1] == 'p' &&
 689           entry->d_name[2] == 'u' &&
 690           entry->d_name[3] >= '0' && entry->d_name[3] <= '9')
 691         n_cpus++;
 692     }
 693     entry = (struct linux_dirent *)(((u8 *)entry) + entry->d_reclen);
 694   }
 695   internal_close(fd);
 696   return n_cpus;
 697 #elif SANITIZER_SOLARIS
 698   return sysconf(_SC_NPROCESSORS_ONLN);
 699 #else
 700   cpu_set_t CPUs;
 701   CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
 702   return CPU_COUNT(&CPUs);
 703 #endif
 704 }
 705
 706 #if SANITIZER_LINUX
 707
 708 # if SANITIZER_ANDROID
 709 static atomic_uint8_t android_log_initialized;
 710
 711 void AndroidLogInit() {
 712   openlog(GetProcessName(), 0, LOG_USER);
 713   atomic_store(&android_log_initialized, 1, memory_order_release);
 714 }
 715
 716 static bool ShouldLogAfterPrintf() {
 717   return atomic_load(&android_log_initialized, memory_order_acquire);
 718 }
 719
 720 extern "C" SANITIZER_WEAK_ATTRIBUTE
 721 int async_safe_write_log(int pri, const char* tag, const char* msg);
 722 extern "C" SANITIZER_WEAK_ATTRIBUTE
 723 int __android_log_write(int prio, const char* tag, const char* msg);
 724
 725 // ANDROID_LOG_INFO is 4, but can't be resolved at runtime.
 726 #define SANITIZER_ANDROID_LOG_INFO 4
 727
 728 // async_safe_write_log is a new public version of __libc_write_log that is
 729 // used behind syslog. It is preferable to syslog as it will not do any dynamic
 730 // memory allocation or formatting.
 731 // If the function is not available, syslog is preferred for L+ (it was broken
 732 // pre-L) as __android_log_write triggers a racey behavior with the strncpy
 733 // interceptor. Fallback to __android_log_write pre-L.
 734 void WriteOneLineToSyslog(const char *s) {
 735   if (&async_safe_write_log) {
 736     async_safe_write_log(SANITIZER_ANDROID_LOG_INFO, GetProcessName(), s);
 737   } else if (AndroidGetApiLevel() > ANDROID_KITKAT) {
 738     syslog(LOG_INFO, "%s", s);
 739   } else {
 740     CHECK(&__android_log_write);
 741     __android_log_write(SANITIZER_ANDROID_LOG_INFO, nullptr, s);
 742   }
 743 }
 744
 745 extern "C" SANITIZER_WEAK_ATTRIBUTE
 746 void android_set_abort_message(const char *);
 747
 748 void SetAbortMessage(const char *str) {
 749   if (&android_set_abort_message)
 750     android_set_abort_message(str);
 751 }
 752 # else
 753 void AndroidLogInit() {}
 754
 755 static bool ShouldLogAfterPrintf() { return true; }
 756
 757 void WriteOneLineToSyslog(const char *s) { syslog(LOG_INFO, "%s", s); }
 758
 759 void SetAbortMessage(const char *str) {}
 760 # endif  // SANITIZER_ANDROID
 761
 762 void LogMessageOnPrintf(const char *str) {
 763   if (common_flags()->log_to_syslog && ShouldLogAfterPrintf())
 764     WriteToSyslog(str);
 765 }
 766
 767 #endif  // SANITIZER_LINUX
 768
 769 #if SANITIZER_LINUX && !SANITIZER_GO
 770 // glibc crashes when using clock_gettime from a preinit_array function as the
 771 // vDSO function pointers haven't been initialized yet. __progname is
 772 // initialized after the vDSO function pointers, so if it exists, is not null
 773 // and is not empty, we can use clock_gettime.
 774 extern "C" SANITIZER_WEAK_ATTRIBUTE char *__progname;
 775 INLINE bool CanUseVDSO() {
 776   // Bionic is safe, it checks for the vDSO function pointers to be initialized.
 777   if (SANITIZER_ANDROID)
 778     return true;
 779   if (&__progname && __progname && *__progname)
 780     return true;
 781   return false;
 782 }
 783
 784 // MonotonicNanoTime is a timing function that can leverage the vDSO by calling
 785 // clock_gettime. real_clock_gettime only exists if clock_gettime is
 786 // intercepted, so define it weakly and use it if available.
 787 extern "C" SANITIZER_WEAK_ATTRIBUTE
 788 int real_clock_gettime(u32 clk_id, void *tp);
 789 u64 MonotonicNanoTime() {
 790   timespec ts;
 791   if (CanUseVDSO()) {
 792     if (&real_clock_gettime)
 793       real_clock_gettime(CLOCK_MONOTONIC, &ts);
 794     else
 795       clock_gettime(CLOCK_MONOTONIC, &ts);
 796   } else {
 797     internal_clock_gettime(CLOCK_MONOTONIC, &ts);
 798   }
 799   return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
 800 }
 801 #else
 802 // Non-Linux & Go always use the syscall.
 803 u64 MonotonicNanoTime() {
 804   timespec ts;
 805   internal_clock_gettime(CLOCK_MONOTONIC, &ts);
 806   return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
 807 }
 808 #endif  // SANITIZER_LINUX && !SANITIZER_GO
 809
 810 #if !SANITIZER_OPENBSD
 811 void ReExec() {
 812   const char *pathname = "/proc/self/exe";
 813
 814 #if SANITIZER_NETBSD
 815   static const int name[] = {
 816       CTL_KERN,
 817       KERN_PROC_ARGS,
 818       -1,
 819       KERN_PROC_PATHNAME,
 820   };
 821   char path[400];
 822   uptr len;
 823
 824   len = sizeof(path);
 825   if (internal_sysctl(name, ARRAY_SIZE(name), path, &len, NULL, 0) != -1)
 826     pathname = path;
 827 #elif SANITIZER_SOLARIS
 828   pathname = getexecname();
 829   CHECK_NE(pathname, NULL);
 830 #elif SANITIZER_USE_GETAUXVAL
 831   // Calling execve with /proc/self/exe sets that as $EXEC_ORIGIN. Binaries that
 832   // rely on that will fail to load shared libraries. Query AT_EXECFN instead.
 833   pathname = reinterpret_cast<const char *>(getauxval(AT_EXECFN));
 834 #endif
 835
 836   uptr rv = internal_execve(pathname, GetArgv(), GetEnviron());
 837   int rverrno;
 838   CHECK_EQ(internal_iserror(rv, &rverrno), true);
 839   Printf("execve failed, errno %d\n", rverrno);
 840   Die();
 841 }
 842 #endif  // !SANITIZER_OPENBSD
 843
 844 } // namespace __sanitizer
 845
 846 #endif