Add new 'delayed' signal handlers.
Allows to defer/queue signal processing for execution on the next event dispatch call, i.e. we can perform any signal action in normal, non-signal context. Example uses: - Reload everything on HUP without writing a global "SIGHUP_received" variable - Dump status of internal Lists on SIGUSR1, etc.
This commit is contained in:
Florian Westphal
parent
c135d0dded
commit
1fe17e246c
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@ -159,7 +159,7 @@ AC_CHECK_FUNCS([ \
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bind gethostbyaddr gethostbyname gethostname inet_ntoa \
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setsid setsockopt socket strcasecmp waitpid],,AC_MSG_ERROR([required function missing!]))
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AC_CHECK_FUNCS(getaddrinfo getnameinfo inet_aton isdigit sigaction snprintf \
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AC_CHECK_FUNCS(getaddrinfo getnameinfo inet_aton isdigit sigaction sigprocmask snprintf \
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vsnprintf strdup strlcpy strlcat strtok_r)
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# -- Configuration options --
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@ -21,7 +21,7 @@ sbin_PROGRAMS = ngircd
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ngircd_SOURCES = ngircd.c array.c channel.c client.c conf.c conn.c conn-func.c \
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conn-ssl.c conn-zip.c hash.c io.c irc.c irc-channel.c irc-info.c irc-login.c \
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irc-mode.c irc-op.c irc-oper.c irc-server.c irc-write.c lists.c log.c \
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match.c op.c numeric.c pam.c parse.c proc.c rendezvous.c resolve.c
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match.c op.c numeric.c pam.c parse.c proc.c rendezvous.c resolve.c sighandlers.c
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ngircd_LDFLAGS = -L../portab -L../tool -L../ipaddr
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@ -477,11 +477,6 @@ Conn_InitListeners( void )
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unsigned int created = 0;
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char *copy, *listen_addr;
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if (!io_library_init(CONNECTION_POOL)) {
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Log(LOG_EMERG, "Cannot initialize IO routines: %s", strerror(errno));
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return -1;
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}
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assert(Conf_ListenAddress);
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/* can't use Conf_ListenAddress directly, see below */
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@ -29,7 +29,6 @@
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#include <time.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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#include <fcntl.h>
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#include <pwd.h>
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#include <grp.h>
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@ -46,6 +45,8 @@
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#include "lists.h"
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#include "log.h"
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#include "parse.h"
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#include "sighandlers.h"
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#include "io.h"
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#include "irc.h"
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#ifdef ZEROCONF
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@ -56,9 +57,6 @@
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#include "ngircd.h"
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static void Initialize_Signal_Handler PARAMS(( void ));
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static void Signal_Handler PARAMS(( int Signal ));
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static void Show_Version PARAMS(( void ));
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static void Show_Help PARAMS(( void ));
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@ -292,8 +290,15 @@ main( int argc, const char *argv[] )
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* when not running in "no daemon" mode: */
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if( ! NGIRCd_NoDaemon ) Log_InitErrorfile( );
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#endif
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if (!io_library_init(CONNECTION_POOL)) {
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Log(LOG_ALERT, "Fatal: Cannot initialize IO routines: %s", strerror(errno));
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exit(1);
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}
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Initialize_Signal_Handler( );
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if (!Signals_Init()) {
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Log(LOG_ALERT, "Fatal: Could not set up signal handlers: %s", strerror(errno));
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exit(1);
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}
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/*
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* create protocol and server identification.
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@ -475,80 +480,6 @@ NGIRCd_Rehash( void )
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} /* NGIRCd_Rehash */
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/**
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* Initialize the signal handler.
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*/
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static void
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Initialize_Signal_Handler( void )
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{
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#ifdef HAVE_SIGACTION
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struct sigaction saction;
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memset( &saction, 0, sizeof( saction ));
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saction.sa_handler = Signal_Handler;
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#ifdef SA_RESTART
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saction.sa_flags |= SA_RESTART;
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#endif
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#ifdef SA_NOCLDWAIT
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saction.sa_flags |= SA_NOCLDWAIT;
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#endif
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sigaction(SIGINT, &saction, NULL);
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sigaction(SIGQUIT, &saction, NULL);
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sigaction(SIGTERM, &saction, NULL);
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sigaction(SIGHUP, &saction, NULL);
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sigaction(SIGCHLD, &saction, NULL);
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/* we handle write errors properly; ignore SIGPIPE */
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saction.sa_handler = SIG_IGN;
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sigaction(SIGPIPE, &saction, NULL);
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#else
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signal(SIGINT, Signal_Handler);
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signal(SIGQUIT, Signal_Handler);
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signal(SIGTERM, Signal_Handler);
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signal(SIGHUP, Signal_Handler);
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signal(SIGCHLD, Signal_Handler);
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signal(SIGPIPE, SIG_IGN);
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#endif
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} /* Initialize_Signal_Handler */
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/**
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* Signal handler of ngIRCd.
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* This function is called whenever ngIRCd catches a signal sent by the
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* user and/or the system to it. For example SIGTERM and SIGHUP.
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* @param Signal Number of the signal to handle.
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*/
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static void
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Signal_Handler( int Signal )
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{
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switch( Signal )
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{
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case SIGTERM:
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case SIGINT:
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case SIGQUIT:
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/* shut down sever */
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NGIRCd_SignalQuit = true;
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break;
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case SIGHUP:
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/* re-read configuration */
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NGIRCd_SignalRehash = true;
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break;
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case SIGCHLD:
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/* child-process exited, avoid zombies */
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while (waitpid( -1, NULL, WNOHANG) > 0)
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;
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break;
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#ifdef DEBUG
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default:
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/* unbekanntes bzw. unbehandeltes Signal */
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Log( LOG_DEBUG, "Got signal %d! Ignored.", Signal );
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#endif
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}
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} /* Signal_Handler */
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/**
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* Display copyright and version information of ngIRCd on the console.
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*/
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@ -21,6 +21,8 @@
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#include "defines.h"
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#define C_ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))
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GLOBAL time_t NGIRCd_Start; /* Startzeitpunkt des Daemon */
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GLOBAL char NGIRCd_StartStr[64];
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@ -120,8 +120,6 @@ static bool Validate_Args PARAMS(( CONN_ID Idx, REQUEST *Req, bool *Closed ));
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static bool Handle_Request PARAMS(( CONN_ID Idx, REQUEST *Req ));
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#define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))
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/**
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* Return the pointer to the global "IRC command structure".
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* This structure, an array of type "COMMAND" describes all the IRC commands
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@ -397,7 +395,7 @@ Handle_Numeric(CLIENT *client, REQUEST *Req)
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/* This server is the target of the numeric */
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num = atoi(Req->command);
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for (i = 0; i < (int) ARRAY_SIZE(Numerics); i++) {
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for (i = 0; i < (int) C_ARRAY_SIZE(Numerics); i++) {
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if (num == Numerics[i].numeric) {
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if (!Numerics[i].function)
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return CONNECTED;
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@ -26,6 +26,7 @@
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#include "conn.h"
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#include "exp.h"
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#include "sighandlers.h"
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#include "proc.h"
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/**
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@ -67,6 +68,7 @@ Proc_Fork(PROC_STAT *proc, int *pipefds, void (*cbfunc)(int, short), int timeout
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return -1;
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case 0:
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/* New child process: */
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Signals_Exit();
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signal(SIGTERM, Proc_GenericSignalHandler);
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signal(SIGALRM, Proc_GenericSignalHandler);
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close(pipefds[0]);
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@ -0,0 +1,220 @@
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/*
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* ngIRCd -- The Next Generation IRC Daemon
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* Please read the file COPYING, README and AUTHORS for more information.
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*/
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#include "portab.h"
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/**
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* @file
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* Signal Handlers: Actions to be performed when the program
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* receives a signal.
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*/
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#include <errno.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include "imp.h"
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#include "io.h"
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#include "log.h"
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#include "ngircd.h"
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#include "sighandlers.h"
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static int signalpipe[2];
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static void Signal_Block(int sig)
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{
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#ifdef HAVE_SIGPROCMASK
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sigset_t set;
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sigemptyset(&set);
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sigaddset(&set, sig);
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sigprocmask(SIG_BLOCK, &set, NULL);
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#endif
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}
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static void Signal_Unblock(int sig)
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{
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#ifdef HAVE_SIGPROCMASK
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sigset_t set;
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sigemptyset(&set);
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sigaddset(&set, sig);
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sigprocmask(SIG_UNBLOCK, &set, NULL);
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#endif
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}
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/**
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* Signal handler of ngIRCd.
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* This function is called whenever ngIRCd catches a signal sent by the
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* user and/or the system to it. For example SIGTERM and SIGHUP.
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*
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* It blocks the signal and queues it for later execution by Signal_Handler_BH.
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* @param Signal Number of the signal to handle.
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*/
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static void Signal_Handler(int Signal)
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{
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switch (Signal) {
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case SIGTERM:
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case SIGINT:
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case SIGQUIT:
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/* shut down sever */
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NGIRCd_SignalQuit = true;
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return;
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case SIGHUP:
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/* re-read configuration */
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NGIRCd_SignalRehash = true;
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return;
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case SIGCHLD:
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/* child-process exited, avoid zombies */
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while (waitpid( -1, NULL, WNOHANG) > 0)
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;
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return;
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}
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/*
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* other signal: queue for later execution.
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* This has the advantage that we are not restricted
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* to functions that can be called safely from signal handlers.
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*/
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if (write(signalpipe[1], &Signal, sizeof(Signal)) != -1)
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Signal_Block(Signal);
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} /* Signal_Handler */
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/**
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* Signal processing handler of ngIRCd.
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* This function is called from the main conn event loop in (io_dispatch)
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* whenever ngIRCd has queued a signal.
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*
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* This function runs in normal context, not from the real signal handler,
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* thus its not necessary to only use functions that are signal safe.
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* @param Signal Number of the signal that was queued.
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*/
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static void Signal_Handler_BH(int Signal)
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{
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switch (Signal) {
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#ifdef DEBUG
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default:
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Log(LOG_DEBUG, "Got signal %d! Ignored.", Signal);
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#endif
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}
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Signal_Unblock(Signal);
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}
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static void Sig_callback(int fd, short UNUSED what)
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{
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int sig, ret;
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(void) what;
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do {
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ret = read(fd, &sig, sizeof(sig));
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if (ret == sizeof(int))
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Signal_Handler_BH(sig);
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} while (ret == sizeof(int));
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if (ret == -1) {
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if (errno == EAGAIN || errno == EINTR)
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return;
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Log(LOG_EMERG, "read from signal pipe: %s", strerror(errno));
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exit(1);
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}
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Log(LOG_EMERG, "EOF on signal pipe");
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exit(1);
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}
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static const int signals_catch[] = { SIGINT, SIGQUIT, SIGTERM, SIGHUP, SIGCHLD, SIGUSR1, SIGUSR2 };
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/**
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* Initialize the signal handlers, catch
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* those signals we are interested in and sets SIGPIPE to be ignored.
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* @return true if initialization was sucessful.
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*/
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bool Signals_Init(void)
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{
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size_t i;
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#ifdef HAVE_SIGACTION
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struct sigaction saction;
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#endif
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if (pipe(signalpipe))
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return false;
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if (!io_setnonblock(signalpipe[0]) ||
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!io_setnonblock(signalpipe[1]))
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return false;
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if (!io_setcloexec(signalpipe[0]) ||
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!io_setcloexec(signalpipe[1]))
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return false;
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#ifdef HAVE_SIGACTION
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memset( &saction, 0, sizeof( saction ));
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saction.sa_handler = Signal_Handler;
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#ifdef SA_RESTART
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saction.sa_flags |= SA_RESTART;
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#endif
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#ifdef SA_NOCLDWAIT
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saction.sa_flags |= SA_NOCLDWAIT;
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#endif
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for (i=0; i < C_ARRAY_SIZE(signals_catch) ; i++)
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sigaction(signals_catch[i], &saction, NULL);
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/* we handle write errors properly; ignore SIGPIPE */
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saction.sa_handler = SIG_IGN;
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sigaction(SIGPIPE, &saction, NULL);
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#else
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for (i=0; i < C_ARRAY_SIZE(signals_catch) ; i++)
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signal(signals_catch[i], Signal_Handler);
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signal(SIGPIPE, SIG_IGN);
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#endif
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return io_event_create(signalpipe[0], IO_WANTREAD,
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Sig_callback);
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} /* Initialize_Signal_Handler */
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/**
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* Restores signals to their default behaviour.
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*
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* This should be called after a fork() in the new
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* child prodcess, especially when we are about to call
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* 3rd party code (e.g. PAM).
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*/
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void Signals_Exit(void)
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{
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size_t i;
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#ifdef HAVE_SIGACTION
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struct sigaction saction;
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memset(&saction, 0, sizeof(saction));
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saction.sa_handler = SIG_DFL;
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for (i=0; i < C_ARRAY_SIZE(signals_catch) ; i++)
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sigaction(signals_catch[i], &saction, NULL);
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sigaction(SIGPIPE, &saction, NULL);
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#else
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for (i=0; i < C_ARRAY_SIZE(signals_catch) ; i++)
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sigaction(signals_catch[i], &saction, NULL);
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signal(SIGPIPE, SIG_DFL);
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#endif
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close(signalpipe[1]);
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close(signalpipe[0]);
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}
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/* -eof- */
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@ -0,0 +1,18 @@
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/*
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||||
* This program is free software; you can redistribute it and/or modify
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||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2 of the License, or
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||||
* (at your option) any later version.
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||||
* Please read the file COPYING, README and AUTHORS for more information.
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||||
*/
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||||
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#ifndef signals_included_
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#define signals_included_
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#include "portab.h"
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bool Signals_Init(void);
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void Signals_Exit(void);
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||||
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#endif
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Loading…
Reference in New Issue