xref: /csrg-svn/lib/libc/gen/syslog.c (revision 36442)
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	5.18 (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 <varargs.h>
46 #include <stdio.h>
47 
48 #define	LOGNAME	"/dev/log"
49 #define	CONSOLE	"/dev/console"
50 
51 static int	LogFile = -1;		/* fd for log */
52 static int	connected;		/* have done connect */
53 static int	LogStat = 0;		/* status bits, set by openlog() */
54 static char	*LogTag = "syslog";	/* string to tag the entry with */
55 static int	LogFacility = LOG_USER;	/* default facility code */
56 
57 syslog(pri, fmt, args)
58 	int pri, args;
59 	char *fmt;
60 {
61 	vsyslog(pri, fmt, &args);
62 }
63 
64 vsyslog(pri, fmt, ap)
65 	int pri;
66 	char *fmt;
67 	va_list ap;
68 {
69 	register int cnt;
70 	register char *p;
71 	time_t now, time();
72 	int pid;
73 	char tbuf[2048], *ctime();
74 
75 	/* see if we should just throw out this message */
76 	if ((u_int)LOG_FAC(pri) >= LOG_NFACILITIES ||
77 	    !LOG_MASK(LOG_PRI(pri)) || (pri &~ (LOG_PRIMASK|LOG_FACMASK)))
78 		return;
79 	if (LogFile < 0 || !connected)
80 		openlog(LogTag, LogStat | LOG_NDELAY, 0);
81 
82 	/* set default facility if none specified */
83 	if ((pri & LOG_FACMASK) == 0)
84 		pri |= LogFacility;
85 
86 	/* build the message */
87 	(void)time(&now);
88 	(void)sprintf(tbuf, "<%d>%.15s ", pri, ctime(&now) + 4);
89 	for (p = tbuf; *p; ++p);
90 	if (LogTag) {
91 		(void)strcpy(p, LogTag);
92 		for (; *p; ++p);
93 	}
94 	if (LogStat & LOG_PID) {
95 		(void)sprintf(p, "[%d]", getpid());
96 		for (; *p; ++p);
97 	}
98 	if (LogTag) {
99 		*p++ = ':';
100 		*p++ = ' ';
101 	}
102 
103 	(void)vsprintf(p, fmt, ap);
104 
105 	/* output the message to the local logger */
106 	if (send(LogFile, tbuf, cnt = strlen(tbuf), 0) >= 0 ||
107 	    !(LogStat&LOG_CONS))
108 		return;
109 
110 	/* output the message to the console */
111 	pid = vfork();
112 	if (pid == -1)
113 		return;
114 	if (pid == 0) {
115 		int fd;
116 		long sigsetmask();
117 
118 		(void)signal(SIGALRM, SIG_DFL);
119 		sigsetmask((long)~sigmask(SIGALRM));
120 		(void)alarm((u_int)5);
121 		if ((fd = open(CONSOLE, O_WRONLY, 0)) < 0)
122 			return;
123 		(void)alarm((u_int)0);
124 		(void)strcat(tbuf, "\r");
125 		p = index(tbuf, '>') + 1;
126 		(void)write(fd, p, cnt + 1 - (p - tbuf));
127 		(void)close(fd);
128 		_exit(0);
129 	}
130 	if (!(LogStat & LOG_NOWAIT))
131 		while ((cnt = wait((int *)0)) > 0 && cnt != pid);
132 }
133 
134 static struct sockaddr SyslogAddr;	/* AF_UNIX address of local logger */
135 /*
136  * OPENLOG -- open system log
137  */
138 openlog(ident, logstat, logfac)
139 	char *ident;
140 	int logstat, logfac;
141 {
142 	if (ident != NULL)
143 		LogTag = ident;
144 	LogStat = logstat;
145 	if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
146 		LogFacility = logfac;
147 	if (LogFile == -1) {
148 		SyslogAddr.sa_family = AF_UNIX;
149 		strncpy(SyslogAddr.sa_data, LOGNAME, sizeof SyslogAddr.sa_data);
150 		if (LogStat & LOG_NDELAY) {
151 			LogFile = socket(AF_UNIX, SOCK_DGRAM, 0);
152 			fcntl(LogFile, F_SETFD, 1);
153 		}
154 	}
155 	if (LogFile != -1 && !connected &&
156 	    connect(LogFile, &SyslogAddr, sizeof(SyslogAddr)) != -1)
157 		connected = 1;
158 }
159 
160 /*
161  * CLOSELOG -- close the system log
162  */
163 closelog()
164 {
165 	(void) close(LogFile);
166 	LogFile = -1;
167 	connected = 0;
168 }
169 
170 static int	LogMask = 0xff;		/* mask of priorities to be logged */
171 /*
172  * SETLOGMASK -- set the log mask level
173  */
174 setlogmask(pmask)
175 	int pmask;
176 {
177 	int omask;
178 
179 	omask = LogMask;
180 	if (pmask != 0)
181 		LogMask = pmask;
182 	return (omask);
183 }
184