| /* |
| * Copyright (C) 2016 The Android Open Source Project |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #include <signal.h> |
| #include <string.h> |
| |
| sighandler_t sigset(int sig, sighandler_t disp) { |
| struct sigaction new_sa; |
| if (disp != SIG_HOLD) { |
| memset(&new_sa, 0, sizeof(new_sa)); |
| new_sa.sa_handler = disp; |
| sigemptyset(&new_sa.sa_mask); |
| } |
| |
| struct sigaction old_sa; |
| if (sigaction(sig, disp == SIG_HOLD ? nullptr : &new_sa, &old_sa) == -1) { |
| return SIG_ERR; |
| } |
| |
| sigset_t new_proc_mask; |
| sigemptyset(&new_proc_mask); |
| sigaddset(&new_proc_mask, sig); |
| |
| sigset_t old_proc_mask; |
| if (sigprocmask(disp == SIG_HOLD ? SIG_BLOCK : SIG_UNBLOCK, |
| &new_proc_mask, &old_proc_mask) == -1) { |
| return SIG_ERR; |
| } |
| |
| return sigismember(&old_proc_mask, sig) ? SIG_HOLD : old_sa.sa_handler; |
| } |