[syslog] Add support for sending console output to a syslog server

Originally-implemented-by: Anselm Martin Hoffmeister <anselm@hoffmeister.be>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/config/console.h

@@ -19,6 +19,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 //#define	CONSOLE_DIRECT_VGA	/* Direct access to VGA card */
 //#define	CONSOLE_BTEXT		/* Who knows what this does? */
 //#define	CONSOLE_PC_KBD		/* Direct access to PC keyboard */
+//#define	CONSOLE_SYSLOG		/* Syslog console */
 
 #include <config/local/console.h>
 

src/include/ipxe/syslog.h

@@ -0,0 +1,36 @@
+#ifndef _IPXE_SYSLOG_H
+#define _IPXE_SYSLOG_H
+
+/** @file
+ *
+ * Syslog protocol
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** Syslog server port */
+#define SYSLOG_PORT 514
+
+/** Syslog line buffer size
+ *
+ * This is a policy decision
+ */
+#define SYSLOG_BUFSIZE 128
+
+/** Syslog facility
+ *
+ * This is a policy decision
+ */
+#define SYSLOG_FACILITY 0 /* kernel */
+
+/** Syslog severity
+ *
+ * This is a policy decision
+ */
+#define SYSLOG_SEVERITY 6 /* informational */
+
+/** Syslog priority */
+#define SYSLOG_PRIORITY( facility, severity ) ( 8 * (facility) + (severity) )
+
+#endif /* _IPXE_SYSLOG_H */

src/net/udp/syslog.c

@@ -0,0 +1,206 @@
+/*
+ * Copyright (C) 2011 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** @file
+ *
+ * Syslog protocol
+ *
+ */
+
+#include <stdint.h>
+#include <byteswap.h>
+#include <ipxe/xfer.h>
+#include <ipxe/open.h>
+#include <ipxe/tcpip.h>
+#include <ipxe/dhcp.h>
+#include <ipxe/settings.h>
+#include <ipxe/console.h>
+#include <ipxe/ansiesc.h>
+#include <ipxe/syslog.h>
+
+/** The syslog server */
+static struct sockaddr_tcpip logserver = {
+	.st_port = htons ( SYSLOG_PORT ),
+};
+
+/** Syslog UDP interface operations */
+static struct interface_operation syslogger_operations[] = {};
+
+/** Syslog UDP interface descriptor */
+static struct interface_descriptor syslogger_desc =
+	INTF_DESC_PURE ( syslogger_operations );
+
+/** The syslog UDP interface */
+static struct interface syslogger = INTF_INIT ( syslogger_desc );
+
+/******************************************************************************
+ *
+ * Console driver
+ *
+ ******************************************************************************
+ */
+
+/** Syslog line buffer */
+static char syslog_buffer[SYSLOG_BUFSIZE];
+
+/** Index into syslog line buffer */
+static unsigned int syslog_idx;
+
+/** Syslog recursion marker */
+static int syslog_entered;
+
+/** Syslog ANSI escape sequence handlers */
+static struct ansiesc_handler syslog_ansiesc_handlers[] = {
+	{ 0, NULL }
+};
+
+/** Syslog ANSI escape sequence context */
+static struct ansiesc_context syslog_ansiesc_ctx = {
+	.handlers = syslog_ansiesc_handlers,
+};
+
+/**
+ * Print a character to syslog console
+ *
+ * @v character		Character to be printed
+ */
+static void syslog_putchar ( int character ) {
+	int rc;
+
+	/* Do nothing if we have no log server */
+	if ( ! logserver.st_family )
+		return;
+
+	/* Ignore if we are already mid-logging */
+	if ( syslog_entered )
+		return;
+
+	/* Strip ANSI escape sequences */
+	character = ansiesc_process ( &syslog_ansiesc_ctx, character );
+	if ( character < 0 )
+		return;
+
+	/* Ignore carriage return */
+	if ( character == '\r' )
+		return;
+
+	/* Treat newline as a terminator */
+	if ( character == '\n' )
+		character = 0;
+
+	/* Add character to buffer */
+	syslog_buffer[syslog_idx++] = character;
+
+	/* Do nothing more unless we reach end-of-line (or end-of-buffer) */
+	if ( ( character != 0 ) &&
+	     ( syslog_idx < ( sizeof ( syslog_buffer ) - 1 /* NUL */ ) ) ) {
+		return;
+	}
+
+	/* Reset to start of buffer */
+	syslog_idx = 0;
+
+	/* Guard against re-entry */
+	syslog_entered = 1;
+
+	/* Send log message */
+	if ( ( rc = xfer_printf ( &syslogger, "<%d>ipxe: %s",
+				  SYSLOG_PRIORITY ( SYSLOG_FACILITY,
+						    SYSLOG_SEVERITY ),
+				  syslog_buffer ) ) != 0 ) {
+		DBG ( "SYSLOG could not send log message: %s\n",
+		      strerror ( rc ) );
+	}
+
+	/* Clear re-entry flag */
+	syslog_entered = 0;
+}
+
+/** Syslog console driver */
+struct console_driver syslog_console __console_driver = {
+	.putchar = syslog_putchar,
+};
+
+/******************************************************************************
+ *
+ * Settings
+ *
+ ******************************************************************************
+ */
+
+/** Syslog server setting */
+struct setting syslog_setting __setting = {
+	.name = "syslog",
+	.description = "Syslog server",
+	.tag = DHCP_LOG_SERVERS,
+	.type = &setting_type_ipv4,
+};
+
+/**
+ * Apply syslog settings
+ *
+ * @ret rc		Return status code
+ */
+static int apply_syslog_settings ( void ) {
+	struct sockaddr_in *sin_logserver =
+		( struct sockaddr_in * ) &logserver;
+	struct in_addr old_addr;
+	int len;
+	int rc;
+
+	/* Fetch log server */
+	old_addr.s_addr = sin_logserver->sin_addr.s_addr;
+	logserver.st_family = 0;
+	if ( ( len = fetch_ipv4_setting ( NULL, &syslog_setting,
+					  &sin_logserver->sin_addr ) ) >= 0 ) {
+		sin_logserver->sin_family = AF_INET;
+	}
+
+	/* Do nothing unless log server has changed */
+	if ( sin_logserver->sin_addr.s_addr == old_addr.s_addr )
+		return 0;
+
+	/* Reset syslog connection */
+	intf_restart ( &syslogger, 0 );
+
+	/* Do nothing unless we have a log server */
+	if ( ! logserver.st_family ) {
+		DBG ( "SYSLOG has no log server\n" );
+		return 0;
+	}
+
+	/* Connect to log server */
+	if ( ( rc = xfer_open_socket ( &syslogger, SOCK_DGRAM,
+				       ( ( struct sockaddr * ) &logserver ),
+				       NULL ) ) != 0 ) {
+		DBG ( "SYSLOG cannot connect to log server: %s\n",
+		      strerror ( rc ) );
+		return rc;
+	}
+	DBG ( "SYSLOG using log server %s\n",
+	      inet_ntoa ( sin_logserver->sin_addr ) );
+
+	return 0;
+}
+
+/** Syslog settings applicator */
+struct settings_applicator syslog_applicator __settings_applicator = {
+	.apply = apply_syslog_settings,
+};