projects/smsdaemon/daemon.cpp

#include <iostream>

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

#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	#include <stdlib.h>
6	#include <cstring>
7
8	#include "daemon.h"
9	#include "common.h"
10
11
12
13	using namespace std;
14
15
16	void signal_handler(int sig)
17	{
18	switch(sig) {
19	case SIGHUP:
20	Common::instance()->logMessage("hangup signal catched");
21	break;
22
23	case SIGTERM:
24	Common::instance()->logMessage("terminate signal catched...exiting");
25	Common::instance()->mainContinue = false;
26	break;
27	}
28	}
29
30	void daemonCleanup()
31	{
32	unlink( Common::instance()->pidfile.c_str() );
33	}
34
35	void daemonize()
36	{
37	int i, lfp;
38	char str[10];
39	Common* cmn = Common::instance();
40
41	if (getuid() != 0)
42	{
43	cout << "Please start this daemon as root\n" << endl;
44	daemon_shutdown(0);
45	}
46
47
48	if (getppid() == 1) /* already a daemon */
49	return;
50
51	i=fork();
52
53	if (i<0) /* fork error */
54	daemon_shutdown(FORK_ERROR);
55	if (i>0) /* parent exits */
56	daemon_shutdown(0);
57	/* child daemon continues */
58
59	setsid(); /* obtain a new process group */
60
61	for (i=getdtablesize(); i>=0; --i)
62	close(i); /close all descriptors/
63
64	i=open("/dev/null", O_RDWR); /* handle std. io */
65	dup(i);
66	dup(i);
67
68	umask(027); /* set newly created file permissions */
69
70	chdir("/tmp"); /* change running directory*/
71
72	/attempt to create lockfile and put a file-lock on it/
73	lfp=open(cmn->pidfile.c_str(), O_RDWR\|O_CREAT, 0640);
74	if (lfp<0) /* can not open */
75	daemon_shutdown(CANT_OPEN_LOCK);
76	if (lockf(lfp,F_TLOCK,0) < 0) /* can not lock */
77	daemon_shutdown(ALREADY_LOCKED);
78
79	/* first instance continues */
80	sprintf(str, "%d\n", getpid() ); /* record pid to lockfile */
81	write(lfp, str, strlen(str) );
82	//signal(SIGCHLD, SIG_IGN); /* ignore child */
83	signal(SIGTSTP, SIG_IGN); /* ignore tty signals */
84	signal(SIGTTOU, SIG_IGN);
85	signal(SIGTTIN, SIG_IGN);
86	signal(SIGHUP, signal_handler); /* catch hangup signal */
87	signal(SIGTERM, signal_handler); /* catch kill signal */
88
89	/this program is now a daemon/
90	setegid( cmn->gid );
91	seteuid( cmn->uid );
92	}