1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <signal.h>
30
31extern "C" void __restore_rt(void);
32extern "C" void __restore(void);
33
34#if defined(__LP64__)
35
36extern "C" int __rt_sigaction(int, const struct __kernel_sigaction*, struct __kernel_sigaction*, size_t);
37
38int sigaction(int signal, const struct sigaction* bionic_new_action, struct sigaction* bionic_old_action) {
39  __kernel_sigaction kernel_new_action;
40  if (bionic_new_action != NULL) {
41    kernel_new_action.sa_flags = bionic_new_action->sa_flags;
42    kernel_new_action.sa_handler = bionic_new_action->sa_handler;
43    kernel_new_action.sa_mask = bionic_new_action->sa_mask;
44#if defined(SA_RESTORER)
45    kernel_new_action.sa_restorer = bionic_new_action->sa_restorer;
46#if defined(__aarch64__)
47    // arm64 has sa_restorer, but unwinding works best if you just let the
48    // kernel supply the default restorer from [vdso]. gdb doesn't care, but
49    // libgcc needs the nop that the kernel includes before the actual code.
50    // (We could add that ourselves, but why bother?)
51#else
52    if (!(kernel_new_action.sa_flags & SA_RESTORER)) {
53      kernel_new_action.sa_flags |= SA_RESTORER;
54      kernel_new_action.sa_restorer = &__restore_rt;
55    }
56#endif
57#endif
58  }
59
60  __kernel_sigaction kernel_old_action;
61  int result = __rt_sigaction(signal,
62                              (bionic_new_action != NULL) ? &kernel_new_action : NULL,
63                              (bionic_old_action != NULL) ? &kernel_old_action : NULL,
64                              sizeof(sigset_t));
65
66  if (bionic_old_action != NULL) {
67    bionic_old_action->sa_flags = kernel_old_action.sa_flags;
68    bionic_old_action->sa_handler = kernel_old_action.sa_handler;
69    bionic_old_action->sa_mask = kernel_old_action.sa_mask;
70#if defined(SA_RESTORER)
71    bionic_old_action->sa_restorer = kernel_old_action.sa_restorer;
72#endif
73  }
74
75  return result;
76}
77
78#else
79
80extern "C" int __sigaction(int, const struct sigaction*, struct sigaction*);
81
82int sigaction(int signal, const struct sigaction* bionic_new_action, struct sigaction* bionic_old_action) {
83  // The 32-bit ABI is broken. struct sigaction includes a too-small sigset_t,
84  // so we have to use sigaction(2) rather than rt_sigaction(2).
85  struct sigaction kernel_new_action;
86  if (bionic_new_action != NULL) {
87    kernel_new_action.sa_flags = bionic_new_action->sa_flags;
88    kernel_new_action.sa_handler = bionic_new_action->sa_handler;
89    kernel_new_action.sa_mask = bionic_new_action->sa_mask;
90#if defined(SA_RESTORER)
91    kernel_new_action.sa_restorer = bionic_new_action->sa_restorer;
92
93    if (!(kernel_new_action.sa_flags & SA_RESTORER)) {
94      kernel_new_action.sa_flags |= SA_RESTORER;
95      kernel_new_action.sa_restorer = (kernel_new_action.sa_flags & SA_SIGINFO) ? &__restore_rt : &__restore;
96    }
97#endif
98  }
99  return __sigaction(signal, (bionic_new_action != NULL) ? &kernel_new_action : NULL, bionic_old_action);
100}
101
102#endif
103