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#include <string.h>
31
32#include "private/sigrtmin.h"
33
34extern "C" void __restore_rt(void);
35extern "C" void __restore(void);
36
37#if defined(__LP64__)
38
39extern "C" int __rt_sigaction(int, const struct __kernel_sigaction*, struct __kernel_sigaction*, size_t);
40
41int sigaction(int signal, const struct sigaction* bionic_new_action, struct sigaction* bionic_old_action) {
42  __kernel_sigaction kernel_new_action;
43  if (bionic_new_action != NULL) {
44    kernel_new_action.sa_flags = bionic_new_action->sa_flags;
45    kernel_new_action.sa_handler = bionic_new_action->sa_handler;
46    kernel_new_action.sa_mask = filter_reserved_signals(bionic_new_action->sa_mask);
47#if defined(SA_RESTORER)
48    kernel_new_action.sa_restorer = bionic_new_action->sa_restorer;
49#if defined(__aarch64__)
50    // arm64 has sa_restorer, but unwinding works best if you just let the
51    // kernel supply the default restorer from [vdso]. gdb doesn't care, but
52    // libgcc needs the nop that the kernel includes before the actual code.
53    // (We could add that ourselves, but why bother?)
54#else
55    if (!(kernel_new_action.sa_flags & SA_RESTORER)) {
56      kernel_new_action.sa_flags |= SA_RESTORER;
57      kernel_new_action.sa_restorer = &__restore_rt;
58    }
59#endif
60#endif
61  }
62
63  __kernel_sigaction kernel_old_action;
64  int result = __rt_sigaction(signal,
65                              (bionic_new_action != NULL) ? &kernel_new_action : NULL,
66                              (bionic_old_action != NULL) ? &kernel_old_action : NULL,
67                              sizeof(sigset_t));
68
69  if (bionic_old_action != NULL) {
70    bionic_old_action->sa_flags = kernel_old_action.sa_flags;
71    bionic_old_action->sa_handler = kernel_old_action.sa_handler;
72    bionic_old_action->sa_mask = kernel_old_action.sa_mask;
73#if defined(SA_RESTORER)
74    bionic_old_action->sa_restorer = kernel_old_action.sa_restorer;
75#endif
76  }
77
78  return result;
79}
80
81__strong_alias(sigaction64, sigaction);
82
83#else
84
85extern "C" int __rt_sigaction(int, const struct sigaction64*, struct sigaction64*, size_t);
86
87int sigaction(int signal, const struct sigaction* bionic_new, struct sigaction* bionic_old) {
88  // The 32-bit ABI is broken. struct sigaction includes a too-small sigset_t,
89  // so we have to translate to struct sigaction64 first.
90  struct sigaction64 kernel_new;
91  if (bionic_new) {
92    kernel_new = {};
93    kernel_new.sa_flags = bionic_new->sa_flags;
94    kernel_new.sa_handler = bionic_new->sa_handler;
95#if defined(SA_RESTORER)
96    kernel_new.sa_restorer = bionic_new->sa_restorer;
97#endif
98    memcpy(&kernel_new.sa_mask, &bionic_new->sa_mask, sizeof(bionic_new->sa_mask));
99  }
100
101  struct sigaction64 kernel_old;
102  int result = sigaction64(signal, bionic_new ? &kernel_new : nullptr, &kernel_old);
103  if (bionic_old) {
104    *bionic_old = {};
105    bionic_old->sa_flags = kernel_old.sa_flags;
106    bionic_old->sa_handler = kernel_old.sa_handler;
107#if defined(SA_RESTORER)
108    bionic_old->sa_restorer = kernel_old.sa_restorer;
109#endif
110    memcpy(&bionic_old->sa_mask, &kernel_old.sa_mask, sizeof(bionic_old->sa_mask));
111  }
112  return result;
113}
114
115int sigaction64(int signal, const struct sigaction64* bionic_new, struct sigaction64* bionic_old) {
116  struct sigaction64 kernel_new;
117  if (bionic_new) {
118    kernel_new = *bionic_new;
119#if defined(SA_RESTORER)
120    if (!(kernel_new.sa_flags & SA_RESTORER)) {
121      kernel_new.sa_flags |= SA_RESTORER;
122      kernel_new.sa_restorer = (kernel_new.sa_flags & SA_SIGINFO) ? &__restore_rt : &__restore;
123    }
124#endif
125    kernel_new.sa_mask = filter_reserved_signals(kernel_new.sa_mask);
126  }
127
128  return __rt_sigaction(signal,
129                        bionic_new ? &kernel_new : nullptr,
130                        bionic_old,
131                        sizeof(kernel_new.sa_mask));
132}
133
134#endif
135