1 /* Report a SIGPIPE signal and exit. 2 Copyright (C) 2008-2021 Free Software Foundation, Inc. 3 4 This program is free software: you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation; either version 3 of the License, or 7 (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License 15 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 16 17 /* Written by Bruno Haible <bruno@clisp.org>, 2008. */ 18 19 #include <config.h> 20 21 /* Specification. */ 22 #include "sigpipe-die.h" 23 24 #include <signal.h> 25 #include <stdlib.h> 26 27 #include "error.h" 28 #include "exitfail.h" 29 30 #include "gettext.h" 31 #define _(msgid) gettext (msgid) 32 33 void 34 sigpipe_die (void) /* */ 35 { 36 error (exit_failure, 0, "%s", 37 _("error writing to a closed pipe or socket")); 38 39 /* Ensure that this function really does not return. */ 40 abort (); 41 } 42 43 static void (*prepare_die_hook) (void); 44 45 /* This is the signal handler for SIGPIPE. It is invoked synchronously, 46 therefore it can make library calls to malloc(), gettext(), exit() etc. - 47 although in general it is undefined behaviour to do such calls from 48 within signal handlers. */ 49 static void 50 sigpipe_die_handler (int sig) /* */ 51 { 52 if (prepare_die_hook != NULL) 53 (*prepare_die_hook) (); 54 sigpipe_die (); 55 } 56 57 void 58 install_sigpipe_die_handler (void (*prepare_die) (void)) /* */ 59 { 60 prepare_die_hook = prepare_die; 61 62 /* Install the handler. */ 63 { 64 struct sigaction action; 65 66 action.sa_handler = sigpipe_die_handler; 67 action.sa_flags = 0; 68 sigemptyset (&action.sa_mask); 69 if (sigaction (SIGPIPE, &action, NULL) >= 0) 70 { 71 /* Unblock the signal (just in case). This is needed because if the 72 signal was blocked in the parent process, it is also blocked in 73 this process: the mask of blocked signals is inherited across 74 fork/exec (except for SIGCHLD). */ 75 sigset_t sigpipe_set; 76 77 sigemptyset (&sigpipe_set); 78 sigaddset (&sigpipe_set, SIGPIPE); 79 sigprocmask (SIG_UNBLOCK, &sigpipe_set, NULL); 80 } 81 } 82 }