libasan/asan_posix.cc

   1 //===-- asan_linux.cc -----------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of AddressSanitizer, an address sanity checker.
   9 //
  10 // Posix-specific details.
  11 //===----------------------------------------------------------------------===//
  12 #if defined(__linux__) || defined(__APPLE__)
  13
  14 #include "asan_internal.h"
  15 #include "asan_interceptors.h"
  16 #include "asan_mapping.h"
  17 #include "asan_report.h"
  18 #include "asan_stack.h"
  19 #include "asan_thread_registry.h"
  20 #include "sanitizer_common/sanitizer_libc.h"
  21 #include "sanitizer_common/sanitizer_procmaps.h"
  22
  23 #include <pthread.h>
  24 #include <signal.h>
  25 #include <stdlib.h>
  26 #include <sys/time.h>
  27 #include <sys/resource.h>
  28 #include <unistd.h>
  29
  30 static const uptr kAltStackSize = SIGSTKSZ * 4;  // SIGSTKSZ is not enough.
  31
  32 namespace __asan {
  33
  34 static void MaybeInstallSigaction(int signum,
  35                                   void (*handler)(int, siginfo_t *, void *)) {
  36   if (!AsanInterceptsSignal(signum))
  37     return;
  38   struct sigaction sigact;
  39   REAL(memset)(&sigact, 0, sizeof(sigact));
  40   sigact.sa_sigaction = handler;
  41   sigact.sa_flags = SA_SIGINFO;
  42   if (flags()->use_sigaltstack) sigact.sa_flags |= SA_ONSTACK;
  43   CHECK(0 == REAL(sigaction)(signum, &sigact, 0));
  44   if (flags()->verbosity >= 1) {
  45     Report("Installed the sigaction for signal %d\n", signum);
  46   }
  47 }
  48
  49 static void     ASAN_OnSIGSEGV(int, siginfo_t *siginfo, void *context) {
  50   uptr addr = (uptr)siginfo->si_addr;
  51   // Write the first message using the bullet-proof write.
  52   if (13 != internal_write(2, "ASAN:SIGSEGV\n", 13)) Die();
  53   uptr pc, sp, bp;
  54   GetPcSpBp(context, &pc, &sp, &bp);
  55   ReportSIGSEGV(pc, sp, bp, addr);
  56 }
  57
  58 void SetAlternateSignalStack() {
  59   stack_t altstack, oldstack;
  60   CHECK(0 == sigaltstack(0, &oldstack));
  61   // If the alternate stack is already in place, do nothing.
  62   if ((oldstack.ss_flags & SS_DISABLE) == 0) return;
  63   // TODO(glider): the mapped stack should have the MAP_STACK flag in the
  64   // future. It is not required by man 2 sigaltstack now (they're using
  65   // malloc()).
  66   void* base = MmapOrDie(kAltStackSize, __FUNCTION__);
  67   altstack.ss_sp = base;
  68   altstack.ss_flags = 0;
  69   altstack.ss_size = kAltStackSize;
  70   CHECK(0 == sigaltstack(&altstack, 0));
  71   if (flags()->verbosity > 0) {
  72     Report("Alternative stack for T%d set: [%p,%p)\n",
  73            asanThreadRegistry().GetCurrentTidOrInvalid(),
  74            altstack.ss_sp, (char*)altstack.ss_sp + altstack.ss_size);
  75   }
  76 }
  77
  78 void UnsetAlternateSignalStack() {
  79   stack_t altstack, oldstack;
  80   altstack.ss_sp = 0;
  81   altstack.ss_flags = SS_DISABLE;
  82   altstack.ss_size = 0;
  83   CHECK(0 == sigaltstack(&altstack, &oldstack));
  84   UnmapOrDie(oldstack.ss_sp, oldstack.ss_size);
  85 }
  86
  87 void InstallSignalHandlers() {
  88   // Set the alternate signal stack for the main thread.
  89   // This will cause SetAlternateSignalStack to be called twice, but the stack
  90   // will be actually set only once.
  91   if (flags()->use_sigaltstack) SetAlternateSignalStack();
  92   MaybeInstallSigaction(SIGSEGV, ASAN_OnSIGSEGV);
  93   MaybeInstallSigaction(SIGBUS, ASAN_OnSIGSEGV);
  94 }
  95
  96 // ---------------------- TSD ---------------- {{{1
  97
  98 static pthread_key_t tsd_key;
  99 static bool tsd_key_inited = false;
 100 void AsanTSDInit(void (*destructor)(void *tsd)) {
 101   CHECK(!tsd_key_inited);
 102   tsd_key_inited = true;
 103   CHECK(0 == pthread_key_create(&tsd_key, destructor));
 104 }
 105
 106 void *AsanTSDGet() {
 107   CHECK(tsd_key_inited);
 108   return pthread_getspecific(tsd_key);
 109 }
 110
 111 void AsanTSDSet(void *tsd) {
 112   CHECK(tsd_key_inited);
 113   pthread_setspecific(tsd_key, tsd);
 114 }
 115
 116 }  // namespace __asan
 117
 118 #endif  // __linux__ || __APPLE_