| Greg Hackmann | 5375bf6 | 2016-02-29 12:35:33 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 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 | sighandler_t sigset(int sig, sighandler_t disp) { |
| 33 | struct sigaction new_sa; |
| 34 | if (disp != SIG_HOLD) { |
| 35 | memset(&new_sa, 0, sizeof(new_sa)); |
| 36 | new_sa.sa_handler = disp; |
| 37 | sigemptyset(&new_sa.sa_mask); |
| 38 | } |
| 39 | |
| 40 | struct sigaction old_sa; |
| 41 | if (sigaction(sig, disp == SIG_HOLD ? nullptr : &new_sa, &old_sa) == -1) { |
| 42 | return SIG_ERR; |
| 43 | } |
| 44 | |
| 45 | sigset_t new_proc_mask; |
| 46 | sigemptyset(&new_proc_mask); |
| 47 | sigaddset(&new_proc_mask, sig); |
| 48 | |
| 49 | sigset_t old_proc_mask; |
| 50 | if (sigprocmask(disp == SIG_HOLD ? SIG_BLOCK : SIG_UNBLOCK, |
| 51 | &new_proc_mask, &old_proc_mask) == -1) { |
| 52 | return SIG_ERR; |
| 53 | } |
| 54 | |
| 55 | return sigismember(&old_proc_mask, sig) ? SIG_HOLD : old_sa.sa_handler; |
| 56 | } |