1 files changed, 319 insertions, 0 deletions
diff --git a/src/log/syslog/syslog.go b/src/log/syslog/syslog.go
new file mode 100644
index 000000000..5e0959916
--- /dev/null
+++ b/src/log/syslog/syslog.go
@@ -0,0 +1,319 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !windows,!nacl,!plan9
+
+// Package syslog provides a simple interface to the system log
+// service. It can send messages to the syslog daemon using UNIX
+// domain sockets, UDP or TCP.
+//
+// Only one call to Dial is necessary. On write failures,
+// the syslog client will attempt to reconnect to the server
+// and write again.
+package syslog
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"strings"
+	"sync"
+	"time"
+)
+
+// The Priority is a combination of the syslog facility and
+// severity. For example, LOG_ALERT | LOG_FTP sends an alert severity
+// message from the FTP facility. The default severity is LOG_EMERG;
+// the default facility is LOG_KERN.
+type Priority int
+
+const severityMask = 0x07
+const facilityMask = 0xf8
+
+const (
+	// Severity.
+
+	// From /usr/include/sys/syslog.h.
+	// These are the same on Linux, BSD, and OS X.
+	LOG_EMERG Priority = iota
+	LOG_ALERT
+	LOG_CRIT
+	LOG_ERR
+	LOG_WARNING
+	LOG_NOTICE
+	LOG_INFO
+	LOG_DEBUG
+)
+
+const (
+	// Facility.
+
+	// From /usr/include/sys/syslog.h.
+	// These are the same up to LOG_FTP on Linux, BSD, and OS X.
+	LOG_KERN Priority = iota << 3
+	LOG_USER
+	LOG_MAIL
+	LOG_DAEMON
+	LOG_AUTH
+	LOG_SYSLOG
+	LOG_LPR
+	LOG_NEWS
+	LOG_UUCP
+	LOG_CRON
+	LOG_AUTHPRIV
+	LOG_FTP
+	_ // unused
+	_ // unused
+	_ // unused
+	_ // unused
+	LOG_LOCAL0
+	LOG_LOCAL1
+	LOG_LOCAL2
+	LOG_LOCAL3
+	LOG_LOCAL4
+	LOG_LOCAL5
+	LOG_LOCAL6
+	LOG_LOCAL7
+)
+
+// A Writer is a connection to a syslog server.
+type Writer struct {
+	priority Priority
+	tag      string
+	hostname string
+	network  string
+	raddr    string
+
+	mu   sync.Mutex // guards conn
+	conn serverConn
+}
+
+// This interface and the separate syslog_unix.go file exist for
+// Solaris support as implemented by gccgo.  On Solaris you can not
+// simply open a TCP connection to the syslog daemon.  The gccgo
+// sources have a syslog_solaris.go file that implements unixSyslog to
+// return a type that satisfies this interface and simply calls the C
+// library syslog function.
+type serverConn interface {
+	writeString(p Priority, hostname, tag, s, nl string) error
+	close() error
+}
+
+type netConn struct {
+	local bool
+	conn  net.Conn
+}
+
+// New establishes a new connection to the system log daemon.  Each
+// write to the returned writer sends a log message with the given
+// priority and prefix.
+func New(priority Priority, tag string) (w *Writer, err error) {
+	return Dial("", "", priority, tag)
+}
+
+// Dial establishes a connection to a log daemon by connecting to
+// address raddr on the specified network.  Each write to the returned
+// writer sends a log message with the given facility, severity and
+// tag.
+// If network is empty, Dial will connect to the local syslog server.
+func Dial(network, raddr string, priority Priority, tag string) (*Writer, error) {
+	if priority < 0 || priority > LOG_LOCAL7|LOG_DEBUG {
+		return nil, errors.New("log/syslog: invalid priority")
+	}
+
+	if tag == "" {
+		tag = os.Args[0]
+	}
+	hostname, _ := os.Hostname()
+
+	w := &Writer{
+		priority: priority,
+		tag:      tag,
+		hostname: hostname,
+		network:  network,
+		raddr:    raddr,
+	}
+
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	err := w.connect()
+	if err != nil {
+		return nil, err
+	}
+	return w, err
+}
+
+// connect makes a connection to the syslog server.
+// It must be called with w.mu held.
+func (w *Writer) connect() (err error) {
+	if w.conn != nil {
+		// ignore err from close, it makes sense to continue anyway
+		w.conn.close()
+		w.conn = nil
+	}
+
+	if w.network == "" {
+		w.conn, err = unixSyslog()
+		if w.hostname == "" {
+			w.hostname = "localhost"
+		}
+	} else {
+		var c net.Conn
+		c, err = net.Dial(w.network, w.raddr)
+		if err == nil {
+			w.conn = &netConn{conn: c}
+			if w.hostname == "" {
+				w.hostname = c.LocalAddr().String()
+			}
+		}
+	}
+	return
+}
+
+// Write sends a log message to the syslog daemon.
+func (w *Writer) Write(b []byte) (int, error) {
+	return w.writeAndRetry(w.priority, string(b))
+}
+
+// Close closes a connection to the syslog daemon.
+func (w *Writer) Close() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	if w.conn != nil {
+		err := w.conn.close()
+		w.conn = nil
+		return err
+	}
+	return nil
+}
+
+// Emerg logs a message with severity LOG_EMERG, ignoring the severity
+// passed to New.
+func (w *Writer) Emerg(m string) (err error) {
+	_, err = w.writeAndRetry(LOG_EMERG, m)
+	return err
+}
+
+// Alert logs a message with severity LOG_ALERT, ignoring the severity
+// passed to New.
+func (w *Writer) Alert(m string) (err error) {
+	_, err = w.writeAndRetry(LOG_ALERT, m)
+	return err
+}
+
+// Crit logs a message with severity LOG_CRIT, ignoring the severity
+// passed to New.
+func (w *Writer) Crit(m string) (err error) {
+	_, err = w.writeAndRetry(LOG_CRIT, m)
+	return err
+}
+
+// Err logs a message with severity LOG_ERR, ignoring the severity
+// passed to New.
+func (w *Writer) Err(m string) (err error) {
+	_, err = w.writeAndRetry(LOG_ERR, m)
+	return err
+}
+
+// Warning logs a message with severity LOG_WARNING, ignoring the
+// severity passed to New.
+func (w *Writer) Warning(m string) (err error) {
+	_, err = w.writeAndRetry(LOG_WARNING, m)
+	return err
+}
+
+// Notice logs a message with severity LOG_NOTICE, ignoring the
+// severity passed to New.
+func (w *Writer) Notice(m string) (err error) {
+	_, err = w.writeAndRetry(LOG_NOTICE, m)
+	return err
+}
+
+// Info logs a message with severity LOG_INFO, ignoring the severity
+// passed to New.
+func (w *Writer) Info(m string) (err error) {
+	_, err = w.writeAndRetry(LOG_INFO, m)
+	return err
+}
+
+// Debug logs a message with severity LOG_DEBUG, ignoring the severity
+// passed to New.
+func (w *Writer) Debug(m string) (err error) {
+	_, err = w.writeAndRetry(LOG_DEBUG, m)
+	return err
+}
+
+func (w *Writer) writeAndRetry(p Priority, s string) (int, error) {
+	pr := (w.priority & facilityMask) | (p & severityMask)
+
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	if w.conn != nil {
+		if n, err := w.write(pr, s); err == nil {
+			return n, err
+		}
+	}
+	if err := w.connect(); err != nil {
+		return 0, err
+	}
+	return w.write(pr, s)
+}
+
+// write generates and writes a syslog formatted string. The
+// format is as follows: <PRI>TIMESTAMP HOSTNAME TAG[PID]: MSG
+func (w *Writer) write(p Priority, msg string) (int, error) {
+	// ensure it ends in a \n
+	nl := ""
+	if !strings.HasSuffix(msg, "\n") {
+		nl = "\n"
+	}
+
+	err := w.conn.writeString(p, w.hostname, w.tag, msg, nl)
+	if err != nil {
+		return 0, err
+	}
+	// Note: return the length of the input, not the number of
+	// bytes printed by Fprintf, because this must behave like
+	// an io.Writer.
+	return len(msg), nil
+}
+
+func (n *netConn) writeString(p Priority, hostname, tag, msg, nl string) error {
+	if n.local {
+		// Compared to the network form below, the changes are:
+		//	1. Use time.Stamp instead of time.RFC3339.
+		//	2. Drop the hostname field from the Fprintf.
+		timestamp := time.Now().Format(time.Stamp)
+		_, err := fmt.Fprintf(n.conn, "<%d>%s %s[%d]: %s%s",
+			p, timestamp,
+			tag, os.Getpid(), msg, nl)
+		return err
+	}
+	timestamp := time.Now().Format(time.RFC3339)
+	_, err := fmt.Fprintf(n.conn, "<%d>%s %s %s[%d]: %s%s",
+		p, timestamp, hostname,
+		tag, os.Getpid(), msg, nl)
+	return err
+}
+
+func (n *netConn) close() error {
+	return n.conn.Close()
+}
+
+// NewLogger creates a log.Logger whose output is written to
+// the system log service with the specified priority. The logFlag
+// argument is the flag set passed through to log.New to create
+// the Logger.
+func NewLogger(p Priority, logFlag int) (*log.Logger, error) {
+	s, err := New(p, "")
+	if err != nil {
+		return nil, err
+	}
+	return log.New(s, "", logFlag), nil
+}