logger: allow to log using tcp transport protocol

This commit fixes error in usage() text, which claimed TCP is default
transport protocol.  That was not true, and neither it should be.  The
syslog messages has traditionally sent using UDP.

For the logger remains using UDP as first transport, but if it fails a
TCP connection is attempted.  If an user wishes remote logging can be
forced to use either UDP or TCP.  The service port for UDP is familiar
'syslog', for TCP the port 'syslog-conn' seems like reasonable default.

[kzak@redhat.com: - rename myopenlog to unix_socket(),
                  - always reset st to -1]

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 88 insertions, 50 deletions

diff --git a/misc-utils/logger.c b/misc-utils/logger.c
index a6fafc187..7bb93abbf 100644
--- a/misc-utils/logger.c
+++ b/misc-utils/logger.c
@@ -58,6 +58,12 @@
 #define	SYSLOG_NAMES
 #include <syslog.h>
 
+enum {
+	TYPE_UDP = (1 << 1),
+	TYPE_TCP = (1 << 2),
+	ALL_TYPES = TYPE_UDP | TYPE_TCP
+};
+
 static int decode(char *name, CODE *codetab)
 {
 	register CODE *c;
@@ -96,57 +102,85 @@ static int pencode(char *s)
 }
 
 static int
-myopenlog(const char *sock, int optd)
+unix_socket(const char *path, const int socket_type)
 {
-	int fd;
+	int fd, i;
 	static struct sockaddr_un s_addr;	/* AF_UNIX address of local logger */
 
-	if (strlen(sock) >= sizeof(s_addr.sun_path))
-		errx(EXIT_FAILURE, _("openlog %s: pathname too long"), sock);
+	if (strlen(path) >= sizeof(s_addr.sun_path))
+		errx(EXIT_FAILURE, _("openlog %s: pathname too long"), path);
 
 	s_addr.sun_family = AF_UNIX;
-	(void)strcpy(s_addr.sun_path, sock);
+	strcpy(s_addr.sun_path, path);
+
+	for (i = 2; i; i--) {
+		int st = -1;
 
-	if (optd == 0) {
-		if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
-			goto udp_socket;
+		if (i == 2 && socket_type & TYPE_UDP)
+			st = SOCK_DGRAM;
+		if (i == 1 && socket_type & TYPE_TCP)
+			st = SOCK_STREAM;
+		if (st == -1 || (fd = socket(AF_UNIX, st, 0)) == -1)
+			continue;
 		if (connect(fd, (struct sockaddr *)&s_addr, sizeof(s_addr)) == -1) {
 			close(fd);
-			goto udp_socket;
+			continue;
 		}
-	} else {
- udp_socket:
-		if ((fd = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
-			err(EXIT_FAILURE, _("socket %s"), sock);
-		if (connect(fd, (struct sockaddr *)&s_addr, sizeof(s_addr)) == -1)
-			err(EXIT_FAILURE, _("connect %s"), sock);
+		break;
 	}
 
+	if (i == 0)
+		err(EXIT_FAILURE, _("socket %s"), path);
+
 	return fd;
 }
 
 static int
-udpopenlog(const char *servername, const char *port) {
-	int fd, errcode;
+inet_socket(const char *servername, const char *port, const int socket_type)
+{
+	int fd, errcode, i;
 	struct addrinfo hints, *res;
+	const char *p = port;
+
+	for (i = 2; i; i--) {
+		memset(&hints, 0, sizeof(hints));
+		if (i == 2 && socket_type & TYPE_UDP) {
+			hints.ai_socktype = SOCK_DGRAM;
+			if (port == NULL)
+				p = "syslog";
+		}
+		if (i == 1 && socket_type & TYPE_TCP) {
+			hints.ai_socktype = SOCK_STREAM;
+			if (port == NULL)
+				p = "syslog-conn";
+		}
+		if (hints.ai_socktype == 0)
+			continue;
+		hints.ai_family = AF_UNSPEC;
+		errcode = getaddrinfo(servername, p, &hints, &res);
+		if (errcode != 0)
+			errx(EXIT_FAILURE, _("getaddrinfo %s:%s: %s"),
+			     servername, p, gai_strerror(errcode));
+		if ((fd = socket(res->ai_family, res->ai_socktype, res->ai_protocol)) == -1) {
+			freeaddrinfo(res);
+			continue;
+		}
+		if (connect(fd, res->ai_addr, res->ai_addrlen) == -1) {
+			freeaddrinfo(res);
+			close(fd);
+			continue;
+		}
 
-	memset(&hints, 0, sizeof(hints));
-	hints.ai_socktype = SOCK_DGRAM;
-	hints.ai_family = AF_UNSPEC;
-
-	errcode = getaddrinfo(servername, port, &hints, &res);
-	if (errcode != 0)
-		errx(EXIT_FAILURE, _("getaddrinfo %s:%s: %s"), servername, port,
-		     gai_strerror(errcode));
-	if ((fd = socket(res->ai_family, res->ai_socktype, res->ai_protocol)) == -1)
-		err(EXIT_FAILURE, _("socket"));
+		freeaddrinfo(res);
+		break;
+	}
 
-	if (connect(fd, res->ai_addr, res->ai_addrlen) == -1)
-		err(EXIT_FAILURE, _("connect"));
+	if (i == 0)
+		errx(EXIT_FAILURE, _("failed to connect %s port %s"), servername, p);
 
-	freeaddrinfo(res);
 	return fd;
 }
+
 static void
 mysyslog(int fd, int logflags, int pri, char *tag, char *msg) {
        char buf[1000], pid[30], *cp, *tp;
@@ -182,7 +216,8 @@ static void __attribute__ ((__noreturn__)) usage(FILE *out)
 	      _(" %s [options] [message]\n"), program_invocation_short_name);
 
 	fputs(_("\nOptions:\n"), out);
-	fputs(_(" -d, --udp             use UDP (TCP is default)\n"
+	fputs(_(" -T, --tcp             use TCP only\n"), out);
+	fputs(_(" -d, --udp             use UDP only\n"
 		" -i, --id              log the process ID too\n"
 		" -f, --file <file>     log the contents of this file\n"
 		" -h, --help            display this help text and exit\n"), out);
@@ -208,9 +243,9 @@ main(int argc, char **argv) {
 	int ch, logflags, pri;
 	char *tag, buf[1024];
 	char *usock = NULL;
-	char *udpserver = NULL;
-	char *udpport = NULL;
-	int LogSock = -1, optd = 0;
+	char *server = NULL;
+	char *port = NULL;
+	int LogSock = -1, socket_type = ALL_TYPES;
 
 	static const struct option longopts[] = {
 		{ "id",		no_argument,	    0, 'i' },
@@ -220,6 +255,7 @@ main(int argc, char **argv) {
 		{ "tag",	required_argument,  0, 't' },
 		{ "socket",	required_argument,  0, 'u' },
 		{ "udp",	no_argument,	    0, 'd' },
+		{ "tcp",	no_argument,	    0, 'T' },
 		{ "server",	required_argument,  0, 'n' },
 		{ "port",	required_argument,  0, 'P' },
 		{ "version",	no_argument,	    0, 'V' },
@@ -235,7 +271,7 @@ main(int argc, char **argv) {
 	tag = NULL;
 	pri = LOG_NOTICE;
 	logflags = 0;
-	while ((ch = getopt_long(argc, argv, "f:ip:st:u:dn:P:Vh",
+	while ((ch = getopt_long(argc, argv, "f:ip:st:u:dTn:P:Vh",
 					    longopts, NULL)) != -1) {
 		switch((char)ch) {
 		case 'f':		/* file to log */
@@ -259,14 +295,16 @@ main(int argc, char **argv) {
 			usock = optarg;
 			break;
 		case 'd':
-			optd = 1;	/* use datagrams */
+			socket_type = TYPE_UDP;
+			break;
+		case 'T':
+			socket_type = TYPE_TCP;
 			break;
-		case 'n':		/* udp socket */
-			optd = 1;	/* use datagrams because udp */
-			udpserver = optarg;
+		case 'n':
+			server = optarg;
 			break;
-		case 'P':		/* change udp port */
-			udpport = optarg;
+		case 'P':
+			port = optarg;
 			break;
 		case 'V':
 			printf(UTIL_LINUX_VERSION);
@@ -282,12 +320,12 @@ main(int argc, char **argv) {
 	argv += optind;
 
 	/* setup for logging */
-	if (!usock && !udpserver)
+	if (!usock && !server)
 		openlog(tag ? tag : getlogin(), logflags, 0);
-	else if (udpserver)
-		LogSock = udpopenlog(udpserver,udpport);
+	else if (server)
+		LogSock = inet_socket(server, port, socket_type);
 	else
-		LogSock = myopenlog(usock, optd);
+		LogSock = unix_socket(usock, socket_type);
 
 	/* log input line if appropriate */
 	if (argc > 0) {
@@ -297,14 +335,14 @@ main(int argc, char **argv) {
 		for (p = buf, endp = buf + sizeof(buf) - 2; *argv;) {
 			len = strlen(*argv);
 			if (p + len > endp && p > buf) {
-			    if (!usock && !udpserver)
+			    if (!usock && !server)
 				syslog(pri, "%s", buf);
 			    else
 				mysyslog(LogSock, logflags, pri, tag, buf);
 				p = buf;
 			}
 			if (len > sizeof(buf) - 1) {
-			    if (!usock && !udpserver)
+			    if (!usock && !server)
 				syslog(pri, "%s", *argv++);
 			    else
 				mysyslog(LogSock, logflags, pri, tag, *argv++);
@@ -316,7 +354,7 @@ main(int argc, char **argv) {
 			}
 		}
 		if (p != buf) {
-		    if (!usock && !udpserver)
+		    if (!usock && !server)
 			syslog(pri, "%s", buf);
 		    else
 			mysyslog(LogSock, logflags, pri, tag, buf);
@@ -330,13 +368,13 @@ main(int argc, char **argv) {
 		    if (len > 0 && buf[len - 1] == '\n')
 			    buf[len - 1] = '\0';
 
-		    if (!usock && !udpserver)
+		    if (!usock && !server)
 			syslog(pri, "%s", buf);
 		    else
 			mysyslog(LogSock, logflags, pri, tag, buf);
 		}
 	}
-	if (!usock && !udpserver)
+	if (!usock && !server)
 		closelog();
 	else
 		close(LogSock);