xref: /csrg-svn/lib/libc/gen/syslog.c (revision 36440)
1 /*
2  * Copyright (c) 1983, 1988 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static char sccsid[] = "@(#)syslog.c	5.17 (Berkeley) 12/19/88";
20 #endif /* LIBC_SCCS and not lint */
21 
22 /*
23  * SYSLOG -- print message on log file
24  *
25  * This routine looks a lot like printf, except that it outputs to the
26  * log file instead of the standard output.  Also:
27  *	adds a timestamp,
28  *	prints the module name in front of the message,
29  *	has some other formatting types (or will sometime),
30  *	adds a newline on the end of the message.
31  *
32  * The output of this routine is intended to be read by syslogd(8).
33  *
34  * Author: Eric Allman
35  * Modified to use UNIX domain IPC by Ralph Campbell
36  */
37 
38 #include <sys/types.h>
39 #include <sys/socket.h>
40 #include <sys/file.h>
41 #include <sys/signal.h>
42 #include <sys/syslog.h>
43 #include <netdb.h>
44 #include <strings.h>
45 #include <stdio.h>
46 
47 #define	LOGNAME	"/dev/log"
48 #define	CONSOLE	"/dev/console"
49 
50 static int	LogFile = -1;		/* fd for log */
51 static int	connected;		/* have done connect */
52 static int	LogStat = 0;		/* status bits, set by openlog() */
53 static char	*LogTag = "syslog";	/* string to tag the entry with */
54 static int	LogFacility = LOG_USER;	/* default facility code */
55 
56 syslog(pri, fmt, args)
57 	int pri, args;
58 	char *fmt;
59 {
60 	register int cnt;
61 	register char *p;
62 	time_t now, time();
63 	int pid;
64 	char tbuf[2048], *ctime();
65 
66 	/* see if we should just throw out this message */
67 	if ((u_int)LOG_FAC(pri) >= LOG_NFACILITIES ||
68 	    !LOG_MASK(LOG_PRI(pri)) || (pri &~ (LOG_PRIMASK|LOG_FACMASK)))
69 		return;
70 	if (LogFile < 0 || !connected)
71 		openlog(LogTag, LogStat | LOG_NDELAY, 0);
72 
73 	/* set default facility if none specified */
74 	if ((pri & LOG_FACMASK) == 0)
75 		pri |= LogFacility;
76 
77 	/* build the message */
78 	(void)time(&now);
79 	(void)sprintf(tbuf, "<%d>%.15s ", pri, ctime(&now) + 4);
80 	for (p = tbuf; *p; ++p);
81 	if (LogTag) {
82 		(void)strcpy(p, LogTag);
83 		for (; *p; ++p);
84 	}
85 	if (LogStat & LOG_PID) {
86 		(void)sprintf(p, "[%d]", getpid());
87 		for (; *p; ++p);
88 	}
89 	if (LogTag) {
90 		*p++ = ':';
91 		*p++ = ' ';
92 	}
93 
94 	(void)vsprintf(p, fmt, &args);
95 
96 	/* output the message to the local logger */
97 	if (send(LogFile, tbuf, cnt = strlen(tbuf), 0) >= 0 ||
98 	    !(LogStat&LOG_CONS))
99 		return;
100 
101 	/* output the message to the console */
102 	pid = vfork();
103 	if (pid == -1)
104 		return;
105 	if (pid == 0) {
106 		int fd;
107 		long sigsetmask();
108 
109 		(void)signal(SIGALRM, SIG_DFL);
110 		sigsetmask((long)~sigmask(SIGALRM));
111 		(void)alarm((u_int)5);
112 		if ((fd = open(CONSOLE, O_WRONLY, 0)) < 0)
113 			return;
114 		(void)alarm((u_int)0);
115 		(void)strcat(tbuf, "\r");
116 		p = index(tbuf, '>') + 1;
117 		(void)write(fd, p, cnt + 1 - (p - tbuf));
118 		(void)close(fd);
119 		_exit(0);
120 	}
121 	if (!(LogStat & LOG_NOWAIT))
122 		while ((cnt = wait((int *)0)) > 0 && cnt != pid);
123 }
124 
125 static struct sockaddr SyslogAddr;	/* AF_UNIX address of local logger */
126 /*
127  * OPENLOG -- open system log
128  */
129 openlog(ident, logstat, logfac)
130 	char *ident;
131 	int logstat, logfac;
132 {
133 	if (ident != NULL)
134 		LogTag = ident;
135 	LogStat = logstat;
136 	if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
137 		LogFacility = logfac;
138 	if (LogFile == -1) {
139 		SyslogAddr.sa_family = AF_UNIX;
140 		strncpy(SyslogAddr.sa_data, LOGNAME, sizeof SyslogAddr.sa_data);
141 		if (LogStat & LOG_NDELAY) {
142 			LogFile = socket(AF_UNIX, SOCK_DGRAM, 0);
143 			fcntl(LogFile, F_SETFD, 1);
144 		}
145 	}
146 	if (LogFile != -1 && !connected &&
147 	    connect(LogFile, &SyslogAddr, sizeof(SyslogAddr)) != -1)
148 		connected = 1;
149 }
150 
151 /*
152  * CLOSELOG -- close the system log
153  */
154 closelog()
155 {
156 	(void) close(LogFile);
157 	LogFile = -1;
158 	connected = 0;
159 }
160 
161 static int	LogMask = 0xff;		/* mask of priorities to be logged */
162 /*
163  * SETLOGMASK -- set the log mask level
164  */
165 setlogmask(pmask)
166 	int pmask;
167 {
168 	int omask;
169 
170 	omask = LogMask;
171 	if (pmask != 0)
172 		LogMask = pmask;
173 	return (omask);
174 }
175