copyninja · June 19, 2011 07:24 · Jun 19, 2011
diff --git a/daemon.c b/daemon.c
@@ -0,0 +1,100 @@
+#include <stdio.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define RUNNING_DIR "/tmp"
+#define LOCK_FILE "daemond.lock"
+#define LOG_FILE "daemond.log"
+
+/*
+ *       daemon.c
+ *
+ *       Copyright 2010 Vasudev Kamath <[email protected]>
+ *     
+ *       This program is free software; you can redistribute it and/or modify
+ *       it under the terms of the GNU Lesser 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, write to the Free Software
+ *       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ *       MA 02110-1301, USA.
+ */
+
+void log_message(char *filename,char *message){
+    FILE *logfile;
+    logfile = fopen(filename,"a");
+    if(!logfile)
+        return;
+    fprintf(logfile,"%s",message);
+    fclose(logfile);
+}
+
+void signal_handler(int sig){
+    switch(sig){
+    case SIGHUP:
+        log_message(LOG_FILE,"Hangup Signal Catched");
+        break;
+    case SIGTERM:
+        log_message(LOG_FILE,"Terminate Signal Catched");
+        exit(0);
+        break;
+    }
+}
+
+void daemonize(){
+    int i,lfp;
+    char str[10];
+
+    if(getppid() == 1)
+        return;
+    i = fork();
+
+    if(i < 0)
+        exit(1);
+    if(i > 0)
+        exit(0);
+    setsid();
+
+    for(i = getdtablesize(); i >= 0; --i)
+        close(i);
+
+    i = open("/dev/null",O_RDWR);
+    dup(i);
+    dup(i);
+    umask(027);
+
+    chdir(RUNNING_DIR);
+
+    lfp = open(LOCK_FILE,O_RDWR|O_CREAT,0640);
+    if(lfp < 0)
+        exit(1);
+    if(lockf(lfp,F_TLOCK,0) < 0)
+        exit(1);
+
+    sprintf(str,"%d\n",getpid());
+    write(lfp,str,strlen(str));
+
+    signal(SIGCHLD,SIG_IGN);
+    signal(SIGTSTP,SIG_IGN);
+    signal(SIGTTOU,SIG_IGN);
+    signal(SIGTTIN,SIG_IGN);
+
+    signal(SIGHUP,signal_handler);
+    signal(SIGTERM,signal_handler);
+}
+
+int main(int argc,char **argv){
+    daemonize();
+    while(1)
+        sleep(1);
+}