1//===-- sanitizer_signal_interceptors.inc -----------------------*- C++ -*-===//
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// Signal interceptors for sanitizers.
10//
11//===----------------------------------------------------------------------===//
12
13#include "interception/interception.h"
14#include "sanitizer_common.h"
15#include "sanitizer_internal_defs.h"
16#include "sanitizer_platform_interceptors.h"
17
18using namespace __sanitizer;
19
20#if SANITIZER_NETBSD
21#define sigaction_symname __sigaction14
22#else
23#define sigaction_symname sigaction
24#endif
25
26#ifndef SIGNAL_INTERCEPTOR_SIGNAL_IMPL
27#define SIGNAL_INTERCEPTOR_SIGNAL_IMPL(func, signum, handler) \
28  { return REAL(func)(signum, handler); }
29#endif
30
31#ifndef SIGNAL_INTERCEPTOR_SIGACTION_IMPL
32#  define SIGNAL_INTERCEPTOR_SIGACTION_IMPL(signum, act, oldact)              \
33    {                                                                         \
34      if (!REAL(sigaction_symname)) {                                         \
35        Printf(                                                               \
36            "Warning: REAL(sigaction_symname) == nullptr. This may happen "   \
37            "if you link with ubsan statically. Sigaction will not work.\n"); \
38        return -1;                                                            \
39      }                                                                       \
40      return REAL(sigaction_symname)(signum, act, oldact);                    \
41    }
42#endif
43
44#if SANITIZER_INTERCEPT_BSD_SIGNAL
45INTERCEPTOR(uptr, bsd_signal, int signum, uptr handler) {
46  if (GetHandleSignalMode(signum) == kHandleSignalExclusive) return 0;
47  SIGNAL_INTERCEPTOR_SIGNAL_IMPL(bsd_signal, signum, handler);
48}
49#define INIT_BSD_SIGNAL COMMON_INTERCEPT_FUNCTION(bsd_signal)
50#else  // SANITIZER_INTERCEPT_BSD_SIGNAL
51#define INIT_BSD_SIGNAL
52#endif  // SANITIZER_INTERCEPT_BSD_SIGNAL
53
54#if SANITIZER_INTERCEPT_SIGNAL_AND_SIGACTION
55INTERCEPTOR(uptr, signal, int signum, uptr handler) {
56  if (GetHandleSignalMode(signum) == kHandleSignalExclusive)
57    return (uptr) nullptr;
58  SIGNAL_INTERCEPTOR_SIGNAL_IMPL(signal, signum, handler);
59}
60#define INIT_SIGNAL COMMON_INTERCEPT_FUNCTION(signal)
61
62INTERCEPTOR(int, sigaction_symname, int signum,
63            const __sanitizer_sigaction *act, __sanitizer_sigaction *oldact) {
64  if (GetHandleSignalMode(signum) == kHandleSignalExclusive) {
65    if (!oldact) return 0;
66    act = nullptr;
67  }
68  SIGNAL_INTERCEPTOR_SIGACTION_IMPL(signum, act, oldact);
69}
70#define INIT_SIGACTION COMMON_INTERCEPT_FUNCTION(sigaction_symname)
71
72namespace __sanitizer {
73int real_sigaction(int signum, const void *act, void *oldact) {
74  return REAL(sigaction_symname)(signum, (const __sanitizer_sigaction *)act,
75                         (__sanitizer_sigaction *)oldact);
76}
77}  // namespace __sanitizer
78#else  // SANITIZER_INTERCEPT_SIGNAL_AND_SIGACTION
79#define INIT_SIGNAL
80#define INIT_SIGACTION
81// We need to have defined REAL(sigaction) on other systems.
82namespace __sanitizer {
83struct __sanitizer_sigaction;
84}
85DEFINE_REAL(int, sigaction, int signum, const __sanitizer_sigaction *act,
86            __sanitizer_sigaction *oldact)
87#endif  // SANITIZER_INTERCEPT_SIGNAL_AND_SIGACTION
88
89static void InitializeSignalInterceptors() {
90  static bool was_called_once;
91  CHECK(!was_called_once);
92  was_called_once = true;
93
94  INIT_BSD_SIGNAL;
95  INIT_SIGNAL;
96  INIT_SIGACTION;
97}
98