asan_posix.cc revision 0870028410087e67a0049c76cb7c64f02c260d24 
1//===-- asan_linux.cc -----------------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file is a part of AddressSanitizer, an address sanity checker.
11//
12// Posix-specific details.
13//===----------------------------------------------------------------------===//
14#if defined(__linux__) || defined(__APPLE__)
15
16#include "asan_internal.h"
17#include "asan_interceptors.h"
18#include "asan_mapping.h"
19#include "asan_report.h"
20#include "asan_stack.h"
21#include "asan_thread_registry.h"
22#include "sanitizer_common/sanitizer_libc.h"
23#include "sanitizer_common/sanitizer_procmaps.h"
24
25#include <pthread.h>
26#include <signal.h>
27#include <stdlib.h>
28#include <sys/time.h>
29#include <sys/resource.h>
30#include <ucontext.h>
31#include <unistd.h>
32
33static const uptr kAltStackSize = SIGSTKSZ * 4;  // SIGSTKSZ is not enough.
34
35namespace __asan {
36
37static void MaybeInstallSigaction(int signum,
38                                  void (*handler)(int, siginfo_t *, void *)) {
39  if (!AsanInterceptsSignal(signum))
40    return;
41  struct sigaction sigact;
42  REAL(memset)(&sigact, 0, sizeof(sigact));
43  sigact.sa_sigaction = handler;
44  sigact.sa_flags = SA_SIGINFO;
45  if (flags()->use_sigaltstack) sigact.sa_flags |= SA_ONSTACK;
46  CHECK(0 == REAL(sigaction)(signum, &sigact, 0));
47  if (flags()->verbosity >= 1) {
48    Report("Installed the sigaction for signal %d\n", signum);
49  }
50}
51
52static void     ASAN_OnSIGSEGV(int, siginfo_t *siginfo, void *context) {
53  uptr addr = (uptr)siginfo->si_addr;
54  // Write the first message using the bullet-proof write.
55  if (13 != internal_write(2, "ASAN:SIGSEGV\n", 13)) Die();
56  uptr pc, sp, bp;
57  GetPcSpBp(context, &pc, &sp, &bp);
58  ReportSIGSEGV(pc, sp, bp, addr);
59}
60
61void SetAlternateSignalStack() {
62  stack_t altstack, oldstack;
63  CHECK(0 == sigaltstack(0, &oldstack));
64  // If the alternate stack is already in place, do nothing.
65  if ((oldstack.ss_flags & SS_DISABLE) == 0) return;
66  // TODO(glider): the mapped stack should have the MAP_STACK flag in the
67  // future. It is not required by man 2 sigaltstack now (they're using
68  // malloc()).
69  void* base = MmapOrDie(kAltStackSize, __FUNCTION__);
70  altstack.ss_sp = base;
71  altstack.ss_flags = 0;
72  altstack.ss_size = kAltStackSize;
73  CHECK(0 == sigaltstack(&altstack, 0));
74  if (flags()->verbosity > 0) {
75    Report("Alternative stack for T%d set: [%p,%p)\n",
76           asanThreadRegistry().GetCurrentTidOrInvalid(),
77           altstack.ss_sp, (char*)altstack.ss_sp + altstack.ss_size);
78  }
79}
80
81void UnsetAlternateSignalStack() {
82  stack_t altstack, oldstack;
83  altstack.ss_sp = 0;
84  altstack.ss_flags = SS_DISABLE;
85  altstack.ss_size = 0;
86  CHECK(0 == sigaltstack(&altstack, &oldstack));
87  UnmapOrDie(oldstack.ss_sp, oldstack.ss_size);
88}
89
90void InstallSignalHandlers() {
91  // Set the alternate signal stack for the main thread.
92  // This will cause SetAlternateSignalStack to be called twice, but the stack
93  // will be actually set only once.
94  if (flags()->use_sigaltstack) SetAlternateSignalStack();
95  MaybeInstallSigaction(SIGSEGV, ASAN_OnSIGSEGV);
96  MaybeInstallSigaction(SIGBUS, ASAN_OnSIGSEGV);
97}
98
99void ClearShadowMemoryForContext(void *context) {
100  ucontext_t *ucp = (ucontext_t*)context;
101  uptr sp = (uptr)ucp->uc_stack.ss_sp;
102  uptr size = ucp->uc_stack.ss_size;
103  // Align to page size.
104  uptr bottom = sp & ~(kPageSize - 1);
105  size += sp - bottom;
106  size = RoundUpTo(size, kPageSize);
107  PoisonShadow(bottom, size, 0);
108}
109
110// ---------------------- TSD ---------------- {{{1
111
112static pthread_key_t tsd_key;
113static bool tsd_key_inited = false;
114void AsanTSDInit(void (*destructor)(void *tsd)) {
115  CHECK(!tsd_key_inited);
116  tsd_key_inited = true;
117  CHECK(0 == pthread_key_create(&tsd_key, destructor));
118}
119
120void *AsanTSDGet() {
121  CHECK(tsd_key_inited);
122  return pthread_getspecific(tsd_key);
123}
124
125void AsanTSDSet(void *tsd) {
126  CHECK(tsd_key_inited);
127  pthread_setspecific(tsd_key, tsd);
128}
129
130}  // namespace __asan
131
132#endif  // __linux__ || __APPLE_
133