/[projects]/smsdaemon/daemon.cpp
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Contents of /smsdaemon/daemon.cpp

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Revision 153 - (show annotations) (download)
Mon Dec 8 13:14:55 2008 UTC (15 years, 5 months ago) by torben
File size: 2770 byte(s)
Add default signal handler

1 #include <iostream>
2 #include <sstream>
3 #include <signal.h>
4 #include <fcntl.h>
5 #include <stdlib.h>
6 #include <cstring>
7
8 #include <sys/types.h>
9 #include <pwd.h>
10 #include <grp.h>
11
12
13 #include "ConfigFile.h"
14 #include "daemon.h"
15 #include "common.h"
16
17
18
19 using namespace std;
20
21
22 void signal_handler(int sig)
23 {
24 switch (sig)
25 {
26 case SIGHUP:
27 Common::instance()->logMessage("hangup signal catched");
28 break;
29
30 case SIGTERM:
31 Common::instance()->logMessage("terminate signal catched...exiting");
32 Common::instance()->mainContinue = false;
33 break;
34 default:
35 std::stringstream ss;
36 ss << "Received unknown signal: " << sig;
37 Common::instance()->logMessage(ss.str());
38 break;
39 }
40 }
41
42 void lookup_uid_values()
43 {
44 Common* cmn = Common::instance();
45
46 std::string userstr = cmn->GetConfigfile()->GetValue("smsdaemon","user");
47 std::string groupstr = cmn->GetConfigfile()->GetValue("smsdaemon","group");
48
49 passwd* pass = getpwnam(userstr.c_str());
50 if (pass != 0)
51 {
52 cmn->uid = pass->pw_uid;
53 }
54 else
55 {
56 cmn->logMessage( string("could not lookup userid: ") + userstr );
57 exit(1);
58 }
59
60 group* grp = getgrnam(groupstr.c_str() );
61 if (grp != 0)
62 {
63 cmn->gid = grp->gr_gid;
64 }
65 else
66 {
67 cmn->logMessage( string("could not lookup groupid: ") + groupstr );
68 exit(1);
69 }
70 }
71
72
73 void daemonCleanup()
74 {
75 unlink( Common::instance()->pidfile.c_str() );
76 }
77
78 void daemonize()
79 {
80 int i, lfp;
81 char str[10];
82 Common* cmn = Common::instance();
83
84 if (getuid() != 0)
85 {
86 cout << "Please start this daemon as root\n" << endl;
87 daemon_shutdown(0);
88 }
89
90
91 if (getppid() == 1) /* already a daemon */
92 return;
93
94 i=fork();
95
96 if (i<0) /* fork error */
97 daemon_shutdown(FORK_ERROR);
98 if (i>0) /* parent exits */
99 daemon_shutdown(0);
100 /* child daemon continues */
101
102 setsid(); /* obtain a new process group */
103
104 for (i=getdtablesize(); i>=0; --i)
105 close(i); /*close all descriptors*/
106
107 i=open("/dev/null", O_RDWR); /* handle std. io */
108 dup(i);
109 dup(i);
110
111 umask(027); /* set newly created file permissions */
112
113 chdir("/tmp"); /* change running directory*/
114
115 /*attempt to create lockfile and put a file-lock on it*/
116 lfp=open(cmn->pidfile.c_str(), O_RDWR|O_CREAT, 0640);
117 if (lfp<0) /* can not open */
118 daemon_shutdown(CANT_OPEN_LOCK);
119 if (lockf(lfp,F_TLOCK,0) < 0) /* can not lock */
120 daemon_shutdown(ALREADY_LOCKED);
121
122 /* first instance continues */
123 sprintf(str, "%d\n", getpid() ); /* record pid to lockfile */
124 write(lfp, str, strlen(str) );
125 //signal(SIGCHLD, SIG_IGN); /* ignore child */
126 signal(SIGTSTP, SIG_IGN); /* ignore tty signals */
127 signal(SIGTTOU, SIG_IGN);
128 signal(SIGTTIN, SIG_IGN);
129 signal(SIGHUP, signal_handler); /* catch hangup signal */
130 signal(SIGTERM, signal_handler); /* catch kill signal */
131
132 /*this program is now a daemon*/
133 setegid( cmn->gid );
134 seteuid( cmn->uid );
135 }

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