Re-design of the original gocryptfs code to work as a library.
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libgocryptfs/internal/tlog/log.go

201 lines
4.6 KiB

// Package tlog is a "toggled logger" that can be enabled and disabled and
// provides coloring.
package tlog
import (
"encoding/hex"
"encoding/json"
"fmt"
"log"
"log/syslog"
"os"
"golang.org/x/term"
)
const (
// ProgramName is used in log reports.
ProgramName = "gocryptfs"
wpanicMsg = "-wpanic turns this warning into a panic: "
)
// Escape sequences for terminal colors. These are set in init() if and only
// if stdout is a terminal. Otherwise they are empty strings.
var (
// ColorReset is used to reset terminal colors.
ColorReset string
// ColorGrey is a terminal color setting string.
ColorGrey string
// ColorRed is a terminal color setting string.
ColorRed string
// ColorGreen is a terminal color setting string.
ColorGreen string
// ColorYellow is a terminal color setting string.
ColorYellow string
)
// JSONDump writes the object in json form.
func JSONDump(obj interface{}) string {
b, err := json.MarshalIndent(obj, "", "\t")
if err != nil {
return err.Error()
}
return string(b)
}
// toggledLogger - a Logger than can be enabled and disabled
type toggledLogger struct {
// Enable or disable output
Enabled bool
// Panic after logging a message, useful in regression tests
Wpanic bool
// Private prefix and postfix are used for coloring
prefix string
postfix string
Logger *log.Logger
}
// trimNewline removes one trailing newline from "msg"
func trimNewline(msg string) string {
if len(msg) == 0 {
return msg
}
if msg[len(msg)-1] == '\n' {
return msg[:len(msg)-1]
}
return msg
}
func (l *toggledLogger) Printf(format string, v ...interface{}) {
if !l.Enabled {
return
}
msg := trimNewline(fmt.Sprintf(format, v...))
l.Logger.Printf(l.prefix + msg + l.postfix)
if l.Wpanic {
l.Logger.Panic(wpanicMsg + msg)
}
}
func (l *toggledLogger) Println(v ...interface{}) {
if !l.Enabled {
return
}
msg := trimNewline(fmt.Sprint(v...))
l.Logger.Println(l.prefix + msg + l.postfix)
if l.Wpanic {
l.Logger.Panic(wpanicMsg + msg)
}
}
// Debug logs debug messages
// Can be enabled by passing "-d"
var Debug *toggledLogger
// Info logs informational message
// Can be disabled by passing "-q"
var Info *toggledLogger
// Warn logs warnings,
// meaning nothing serious by itself but might indicate problems.
// Passing "-wpanic" will make this function panic after printing the message.
var Warn *toggledLogger
// Fatal error, we are about to exit
var Fatal *toggledLogger
func init() {
if term.IsTerminal(int(os.Stdout.Fd())) {
ColorReset = "\033[0m"
ColorGrey = "\033[2m"
ColorRed = "\033[31m"
ColorGreen = "\033[32m"
ColorYellow = "\033[33m"
}
Debug = &toggledLogger{
Logger: log.New(os.Stdout, "", 0),
}
Info = &toggledLogger{
Enabled: true,
Logger: log.New(os.Stdout, "", 0),
}
Warn = &toggledLogger{
Enabled: true,
Logger: log.New(os.Stderr, "", 0),
prefix: ColorYellow,
postfix: ColorReset,
}
Fatal = &toggledLogger{
Enabled: true,
Logger: log.New(os.Stderr, "", 0),
prefix: ColorRed,
postfix: ColorReset,
}
}
// SwitchToSyslog redirects the output of this logger to syslog.
// p = facility | severity
func (l *toggledLogger) SwitchToSyslog(p syslog.Priority) {
w, err := syslog.New(p, ProgramName)
if err != nil {
Warn.Printf("SwitchToSyslog: %v", err)
} else {
l.Logger.SetOutput(w)
// Disable colors
l.prefix = ""
l.postfix = ""
}
}
// SwitchLoggerToSyslog redirects the default log.Logger that the go-fuse lib uses
// to syslog.
func SwitchLoggerToSyslog() {
p := syslog.LOG_USER | syslog.LOG_WARNING
w, err := syslog.New(p, ProgramName)
if err != nil {
Warn.Printf("SwitchLoggerToSyslog: %v", err)
} else {
log.SetPrefix("go-fuse: ")
// Disable printing the timestamp, syslog already provides that
log.SetFlags(0)
log.SetOutput(w)
}
}
// PrintMasterkeyReminder reminds the user that he should store the master key in
// a safe place.
func PrintMasterkeyReminder(key []byte) {
if !Info.Enabled {
// Quiet mode
return
}
if !term.IsTerminal(int(os.Stdout.Fd())) {
// We don't want the master key to end up in a log file
Info.Printf("Not running on a terminal, suppressing master key display\n")
return
}
h := hex.EncodeToString(key)
var hChunked string
// Try to make it less scary by splitting it up in chunks
for i := 0; i < len(h); i += 8 {
hChunked += h[i : i+8]
if i < 52 {
hChunked += "-"
}
if i == 24 {
hChunked += "\n "
}
}
Info.Printf(`
Your master key is:
%s
If the gocryptfs.conf file becomes corrupted or you ever forget your password,
there is only one hope for recovery: The master key. Print it to a piece of
paper and store it in a drawer. This message is only printed once.
`, ColorGrey+hChunked+ColorReset)
}