/* Unix SMB/CIFS implementation. signal handling functions Copyright (C) Andrew Tridgell 1998 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include "util/util.h" #include <sys/types.h> #include <sys/wait.h> /** * @file * @brief Signal handling */ /**************************************************************************** Catch child exits and reap the child zombie status. ****************************************************************************/ static void sig_cld(int signum) { while (waitpid((pid_t)-1,(int *)NULL, WNOHANG) > 0) ; /* * Turns out it's *really* important not to * restore the signal handler here if we have real POSIX * signal handling. If we do, then we get the signal re-delivered * immediately - hey presto - instant loop ! JRA. */ #if !defined(HAVE_SIGACTION) CatchSignal(SIGCLD, sig_cld); #endif } /**************************************************************************** catch child exits - leave status; ****************************************************************************/ static void sig_cld_leave_status(int signum) { /* * Turns out it's *really* important not to * restore the signal handler here if we have real POSIX * signal handling. If we do, then we get the signal re-delivered * immediately - hey presto - instant loop ! JRA. */ #if !defined(HAVE_SIGACTION) CatchSignal(SIGCLD, sig_cld_leave_status); #endif } /** Block sigs. **/ void BlockSignals(bool block, int signum) { #ifdef HAVE_SIGPROCMASK sigset_t set; sigemptyset(&set); sigaddset(&set,signum); sigprocmask(block?SIG_BLOCK:SIG_UNBLOCK,&set,NULL); #elif defined(HAVE_SIGBLOCK) if (block) { sigblock(sigmask(signum)); } else { sigsetmask(siggetmask() & ~sigmask(signum)); } #else /* yikes! This platform can't block signals? */ static int done; if (!done) { DEBUG(0,("WARNING: No signal blocking available\n")); done=1; } #endif } /** Catch a signal. This should implement the following semantics: 1) The handler remains installed after being called. 2) The signal should be blocked during handler execution. **/ void (*CatchSignal(int signum,void (*handler)(int )))(int) { #ifdef HAVE_SIGACTION struct sigaction act; struct sigaction oldact; ZERO_STRUCT(act); act.sa_handler = handler; #ifdef SA_RESTART /* * We *want* SIGALRM to interrupt a system call. */ if(signum != SIGALRM) act.sa_flags = SA_RESTART; #endif sigemptyset(&act.sa_mask); sigaddset(&act.sa_mask,signum); sigaction(signum,&act,&oldact); return oldact.sa_handler; #else /* !HAVE_SIGACTION */ /* FIXME: need to handle sigvec and systems with broken signal() */ return signal(signum, handler); #endif } /** Ignore SIGCLD via whatever means is necessary for this OS. **/ void CatchChild(void) { CatchSignal(SIGCLD, sig_cld); } /** Catch SIGCLD but leave the child around so it's status can be reaped. **/ void CatchChildLeaveStatus(void) { CatchSignal(SIGCLD, sig_cld_leave_status); }