projects/smsdaemon/daemon.cpp

#include <iostream>

#include <signal.h>
#include <fcntl.h>

#include "daemon.h"
#include "common.h"


using namespace std;

 
void signal_handler(int sig)
{
        switch(sig) {
                case SIGHUP:
                        Common::instance()->logMessage("hangup signal catched");
                        break;

                case SIGTERM:
                        Common::instance()->logMessage("terminate signal catched...exiting");
                        Common::instance()->mainContinue = false;
                        break;
        }
}

void daemonCleanup()
{
        unlink( Common::instance()->pidfile.c_str() );
}

void daemonize()
{       
        int i, lfp;
        char str[10];
        Common* cmn = Common::instance();

        if (getuid() != 0)
        {
                cout << "Please start this daemon as root\n" << endl;
                daemon_shutdown(0);
        }

                                        
        if (getppid() == 1) /* already a daemon */
                return;
                                                        
        i=fork();
                                                        
        if (i<0) /* fork error */
                daemon_shutdown(FORK_ERROR);
        if (i>0) /* parent exits */
                daemon_shutdown(0);
        /* child daemon continues */
                                                                
        setsid(); /* obtain a new process group */
                                                                                
        for (i=getdtablesize(); i>=0; --i)
                close(i); /*close all descriptors*/
                                                                                                
        i=open("/dev/null", O_RDWR); /* handle std. io */
        dup(i); 
        dup(i);
                                                                                                                
        umask(027); /* set newly created file permissions */
                                                                                                                        
        chdir("/tmp"); /* change running directory*/
        
        /*attempt to create lockfile and put a file-lock on it*/
        lfp=open(cmn->pidfile.c_str(), O_RDWR|O_CREAT, 0640);
        if (lfp<0) /* can not open */
                daemon_shutdown(CANT_OPEN_LOCK);
        if (lockf(lfp,F_TLOCK,0) < 0) /* can not lock */
                daemon_shutdown(ALREADY_LOCKED);
                                        
        /* first instance continues */
        sprintf(str, "%d\n", getpid() ); /* record pid to lockfile */
        write(lfp, str, strlen(str) );
        //signal(SIGCHLD, SIG_IGN); /* ignore child */
        signal(SIGTSTP, SIG_IGN); /* ignore tty signals */
        signal(SIGTTOU, SIG_IGN);
        signal(SIGTTIN, SIG_IGN);
        signal(SIGHUP, signal_handler); /* catch hangup signal */
        signal(SIGTERM, signal_handler); /* catch kill signal */        

        /*this program is now a daemon*/
        setegid( cmn->gid );
        seteuid( cmn->uid );
}
1	#include <iostream>
2
3	#include <signal.h>
4	#include <fcntl.h>
5
6	#include "daemon.h"
7	#include "common.h"
8
9
10
11	using namespace std;
12
13
14	void signal_handler(int sig)
15	{
16	switch(sig) {
17	case SIGHUP:
18	Common::instance()->logMessage("hangup signal catched");
19	break;
20
21	case SIGTERM:
22	Common::instance()->logMessage("terminate signal catched...exiting");
23	Common::instance()->mainContinue = false;
24	break;
25	}
26	}
27
28	void daemonCleanup()
29	{
30	unlink( Common::instance()->pidfile.c_str() );
31	}
32
33	void daemonize()
34	{
35	int i, lfp;
36	char str[10];
37	Common* cmn = Common::instance();
38
39	if (getuid() != 0)
40	{
41	cout << "Please start this daemon as root\n" << endl;
42	daemon_shutdown(0);
43	}
44
45
46	if (getppid() == 1) /* already a daemon */
47	return;
48
49	i=fork();
50
51	if (i<0) /* fork error */
52	daemon_shutdown(FORK_ERROR);
53	if (i>0) /* parent exits */
54	daemon_shutdown(0);
55	/* child daemon continues */
56
57	setsid(); /* obtain a new process group */
58
59	for (i=getdtablesize(); i>=0; --i)
60	close(i); /close all descriptors/
61
62	i=open("/dev/null", O_RDWR); /* handle std. io */
63	dup(i);
64	dup(i);
65
66	umask(027); /* set newly created file permissions */
67
68	chdir("/tmp"); /* change running directory*/
69
70	/attempt to create lockfile and put a file-lock on it/
71	lfp=open(cmn->pidfile.c_str(), O_RDWR\|O_CREAT, 0640);
72	if (lfp<0) /* can not open */
73	daemon_shutdown(CANT_OPEN_LOCK);
74	if (lockf(lfp,F_TLOCK,0) < 0) /* can not lock */
75	daemon_shutdown(ALREADY_LOCKED);
76
77	/* first instance continues */
78	sprintf(str, "%d\n", getpid() ); /* record pid to lockfile */
79	write(lfp, str, strlen(str) );
80	//signal(SIGCHLD, SIG_IGN); /* ignore child */
81	signal(SIGTSTP, SIG_IGN); /* ignore tty signals */
82	signal(SIGTTOU, SIG_IGN);
83	signal(SIGTTIN, SIG_IGN);
84	signal(SIGHUP, signal_handler); /* catch hangup signal */
85	signal(SIGTERM, signal_handler); /* catch kill signal */
86
87	/this program is now a daemon/
88	setegid( cmn->gid );
89	seteuid( cmn->uid );
90	}