Upstream-Status: Pending

Subject: syslogd.c: add systemd support

1. add socket activation support
2. unlink /dev/log if it's not provided by systemd

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
---
 syslogd.c | 157 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 137 insertions(+), 20 deletions(-)

diff --git a/syslogd.c b/syslogd.c
index acfd8f1..81e45e6 100644
--- a/syslogd.c
+++ b/syslogd.c
@@ -602,6 +602,9 @@ static char sccsid[] = "@(#)syslogd.c	5.27 (Berkeley) 10/10/88";
 #define _PATH_LOG	"/dev/log"
 #endif
 
+/* systemd support */
+#define SD_LISTEN_FDS_START 3
+
 char	*ConfFile = _PATH_LOGCONF;
 char	*PidFile = _PATH_LOGPID;
 char	ctty[] = _PATH_CONSOLE;
@@ -612,6 +615,7 @@ int inetm = 0;
 static int debugging_on = 0;
 static int nlogs = -1;
 static int restart = 0;
+static int socket_from_systemd = 0;
 
 #define MAXFUNIX	20
 
@@ -822,6 +826,8 @@ int decode(char *name, struct code *codetab);
 static void dprintf(char *, ...);
 static void allocate_log(void);
 void sighup_handler();
+/* systemd support */
+int sd_listen_fds(void);
 
 #ifdef SYSLOG_UNIXAF
 static int create_unix_socket(const char *path);
@@ -963,9 +969,37 @@ int main(argc, argv)
 				 */
 				exit(1);
 			}
+
+			/* We keep stdout and stderr open in case we have to emit something */
+			close(0);
+			i = 3;
+
+			/* Trying to pass on LISTEN_PID with appropriate value */
+			const char *e;
+			unsigned long l;
+			char buf[24] = { '\0' };
+			int sd_fds;
+
+			if ( (e = getenv("LISTEN_PID")) ) {
+				errno = 0;
+				l = strtoul(e, NULL, 10);
+				if (errno == 0) {
+					if (getppid() == (pid_t)l) {
+						snprintf(buf,sizeof(buf), "%d", (int)getpid());
+						setenv("LISTEN_PID", buf, 1);
+					} 
+				}
+			}
+
 			signal (SIGTERM, SIG_DFL);
 			num_fds = getdtablesize();
-			for (i= 0; i < num_fds; i++)
+
+			/* close all further fds except of the fds provided by systemd */
+			sd_fds = sd_listen_fds();
+			if (sd_fds > 0) {
+				i = SD_LISTEN_FDS_START + sd_fds;
+			}
+			for ( ; i < num_fds; i++)
 				(void) close(i);
 			untty();
 		}
@@ -1248,28 +1282,37 @@ static int create_unix_socket(const char *path)
 {
 	struct sockaddr_un sunx;
 	int fd;
+	int n;
 	char line[MAXLINE +1];
 
-	if (path[0] == '\0')
+	n = sd_listen_fds();
+	if (n > 1) {
 		return -1;
-
-	(void) unlink(path);
-
-	memset(&sunx, 0, sizeof(sunx));
-	sunx.sun_family = AF_UNIX;
-	(void) strncpy(sunx.sun_path, path, sizeof(sunx.sun_path));
-	fd = socket(AF_UNIX, SOCK_DGRAM, 0);
-	if (fd < 0 || bind(fd, (struct sockaddr *) &sunx,
-			   sizeof(sunx.sun_family)+strlen(sunx.sun_path)) < 0 ||
-	    chmod(path, 0666) < 0) {
-		(void) snprintf(line, sizeof(line), "cannot create %s", path);
-		logerror(line);
-		dprintf("cannot create %s (%d).\n", path, errno);
-		close(fd);
+	} else if (n == 1) {
+		socket_from_systemd = 1;
+		fd = SD_LISTEN_FDS_START + 0;
+	} else {
+		if (path[0] == '\0')
+			return -1;
+
+		(void) unlink(path);
+
+		memset(&sunx, 0, sizeof(sunx));
+		sunx.sun_family = AF_UNIX;
+		(void) strncpy(sunx.sun_path, path, sizeof(sunx.sun_path));
+		fd = socket(AF_UNIX, SOCK_DGRAM, 0);
+		if (fd < 0 || bind(fd, (struct sockaddr *) &sunx,
+				   sizeof(sunx.sun_family)+strlen(sunx.sun_path)) < 0 ||
+		    chmod(path, 0666) < 0) {
+			(void) snprintf(line, sizeof(line), "cannot create %s", path);
+			logerror(line);
+			dprintf("cannot create %s (%d).\n", path, errno);
+			close(fd);
 #ifndef SYSV
-		die(0);
+			die(0);
 #endif
-		return -1;
+			return -1;
+		}
 	}
 	return fd;
 }
@@ -1998,12 +2041,27 @@ void wallmsg(f, iov)
 	/* open the user login file */
 	setutent();
 
-
 	/*
 	 * Might as well fork instead of using nonblocking I/O
 	 * and doing notty().
 	 */
 	if (fork() == 0) {
+		/* Trying to pass on the LISTEN_PID with appropriate value */
+		const char *e;
+		unsigned long l;
+		char buf[24] = { '\0' };
+
+		if ( (e = getenv("LISTEN_PID")) ) {
+			errno = 0;
+			l = strtoul(e, NULL, 10);
+			if (errno == 0) {
+				if (getppid() == (pid_t)l) {
+					snprintf(buf,sizeof(buf), "%d", (int)getpid());
+					setenv("LISTEN_PID", buf, 1);
+				}
+			} 
+		}
+
 		(void) signal(SIGTERM, SIG_DFL);
 		(void) alarm(0);
 #ifndef SYSV
@@ -2254,9 +2312,15 @@ void die(sig)
 	if (InetInuse) close(inetm);
 
 	/* Clean-up files. */
-        for (i = 0; i < nfunix; i++)
+	if (socket_from_systemd) {
+		i = 1;
+	} else {
+		i = 0;
+	}
+	for (; i < nfunix; i++)
 		if (funixn[i] && funix[i] != -1)
 			(void)unlink(funixn[i]);
+
 #ifndef TESTING
 	(void) remove_pid(PidFile);
 #endif
@@ -2896,6 +2960,59 @@ void sighup_handler()
 	return;
 }
 
+int sd_listen_fds() {
+	int r, fd;
+	const char *e;
+	unsigned long l;
+
+	e = getenv("LISTEN_PID");
+	if (!e) {
+		return 0;
+	}
+
+	errno = 0;
+	l = strtoul(e, NULL, 10);
+
+	if (errno != 0) {
+		return -errno;
+	}
+
+	if (getpid() != (pid_t)l) {
+		return 0;
+	}
+
+	e = getenv("LISTEN_FDS");
+	if (!e) {
+		return 0;
+	}
+
+	errno = 0;
+	l = strtoul(e, NULL, 10);
+
+	if (errno != 0) {
+		return -errno;
+	}
+
+	for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + (int)l; fd++) {
+		int flags;
+
+		flags = fcntl(fd, F_GETFD);
+		if (flags < 0) {
+			return -errno;
+		}
+
+		if (flags & FD_CLOEXEC)
+			continue;
+
+		if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) < 0) {
+			return -errno;
+		}
+	}
+
+	r = (int)l;
+
+	return r;
+}
 /*
  * Local variables:
  *  c-indent-level: 8
-- 
1.9.1