If the send() to the AF_UNIX socket to the syslogd fails, attempt to

reconnect once using the saved openlog() parameters.

This helps one of the system startup race conditions. If syslogd takes too
long to get going, some daemons can fail the connection and forever log
to the console even though the syslogd is running.  That is ..unfortunate..

1 files changed, 56 insertions, 18 deletions

diff --git a/lib/libc/gen/syslog.c b/lib/libc/gen/syslog.c
index 1ef9a66..1949332 100644
--- a/lib/libc/gen/syslog.c
+++ b/lib/libc/gen/syslog.c
@@ -36,7 +36,7 @@
 static char sccsid[] = "From: @(#)syslog.c	8.4 (Berkeley) 3/18/94";
 */
 static const char rcsid[] =
-  "$Id: syslog.c,v 1.6 1995/10/21 07:05:01 peter Exp $";
+  "$Id: syslog.c,v 1.7 1995/10/22 14:37:08 phk Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/types.h>
@@ -61,12 +61,16 @@ static const char rcsid[] =
 
 static int	LogFile = -1;		/* fd for log */
 static int	connected;		/* have done connect */
+static int	opened;			/* have done openlog() */
 static int	LogStat = 0;		/* status bits, set by openlog() */
 static const char *LogTag = NULL;	/* string to tag the entry with */
 static int	LogFacility = LOG_USER;	/* default facility code */
 static int	LogMask = 0xff;		/* mask of priorities to be logged */
 extern char	*__progname;		/* Program name, from crt0. */
 
+static void	disconnectlog __P((void)); /* disconnect from syslogd */
+static void	connectlog __P((void));	/* (re)connect to syslogd */
+
 /*
  * Format of the magic cookie passed through the stdio hook
  */
@@ -80,7 +84,8 @@ struct bufcookie {
  * XXX: Maybe one day, dynamically allocate it so that the line length
  *      is `unlimited'.
  */
-static writehook(cookie, buf, len)
+static
+int writehook(cookie, buf, len)
 	void	*cookie;	/* really [struct bufcookie *] */
 	char	*buf;		/* characters to copy */
 	int	len;		/* length to copy */
@@ -233,8 +238,18 @@ vsyslog(pri, fmt, ap)
 	}
 
 	/* Get connected, output the message to the local logger. */
-	if (!connected)
+	if (!opened)
 		openlog(LogTag, LogStat | LOG_NDELAY, 0);
+	connectlog();
+	if (send(LogFile, tbuf, cnt, 0) >= 0)
+		return;
+
+	/*
+	 * If the send() failed, the odds are syslogd was restarted.
+	 * Make one (only) attempt to reconnect to /dev/log.
+	 */
+	disconnectlog();
+	connectlog();
 	if (send(LogFile, tbuf, cnt, 0) >= 0)
 		return;
 
@@ -261,33 +276,56 @@ vsyslog(pri, fmt, ap)
 
 static struct sockaddr SyslogAddr;	/* AF_UNIX address of local logger */
 
-void
-openlog(ident, logstat, logfac)
-	const char *ident;
-	int logstat, logfac;
+static void
+disconnectlog()
 {
-	if (ident != NULL)
-		LogTag = ident;
-	LogStat = logstat;
-	if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
-		LogFacility = logfac;
+	/*
+	 * If the user closed the FD and opened another in the same slot,
+	 * that's their problem.  They should close it before calling on
+	 * system services.
+	 */
+	if (LogFile != -1) {
+		close(LogFile);
+		LogFile = -1;
+	}
+	connected = 0;			/* retry connect */
+}
 
+static void
+connectlog()
+{
 	if (LogFile == -1) {
 		SyslogAddr.sa_family = AF_UNIX;
 		(void)strncpy(SyslogAddr.sa_data, _PATH_LOG,
 		    sizeof(SyslogAddr.sa_data));
-		if (LogStat & LOG_NDELAY) {
-			if ((LogFile = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
-				return;
-			(void)fcntl(LogFile, F_SETFD, 1);
-		}
+		if ((LogFile = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
+			return;
+		(void)fcntl(LogFile, F_SETFD, 1);
 	}
-	if (LogFile != -1 && !connected)
+	if (LogFile != -1 && !connected) {
 		if (connect(LogFile, &SyslogAddr, sizeof(SyslogAddr)) == -1) {
 			(void)close(LogFile);
 			LogFile = -1;
 		} else
 			connected = 1;
+	}
+}
+
+void
+openlog(ident, logstat, logfac)
+	const char *ident;
+	int logstat, logfac;
+{
+	if (ident != NULL)
+		LogTag = ident;
+	LogStat = logstat;
+	if (logfac != 0 && (logfac &~ LOG_FACMASK) == 0)
+		LogFacility = logfac;
+
+	if (LogStat & LOG_NDELAY)	/* open immediately */
+		connectlog();
+
+	opened = 1;	/* ident and facility has been set */
 }
 
 void