main: add "-info" option

Pretty-prints the config while stripping out sensitive
(and uninteresting) data

https://github.com/rfjakob/gocryptfs/issues/111

1 files changed, 45 insertions, 0 deletions

diff --git a/info.go b/info.go
new file mode 100644
index 0000000..c2e0038
--- /dev/null
+++ b/info.go
@@ -0,0 +1,45 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+
+	"github.com/rfjakob/gocryptfs/internal/configfile"
+	"github.com/rfjakob/gocryptfs/internal/contentenc"
+	"github.com/rfjakob/gocryptfs/internal/exitcodes"
+	"github.com/rfjakob/gocryptfs/internal/tlog"
+)
+
+// info pretty-prints the contents of the config file at "filename" for human
+// consumption, stripping out sensitive data.
+// This is called when you pass the "-info" option.
+func info(filename string) {
+	// Read from disk
+	js, err := ioutil.ReadFile(filename)
+	if err != nil {
+		tlog.Fatal.Printf("info: ReadFile: %#v\n", err)
+		os.Exit(exitcodes.LoadConf)
+	}
+	// Unmarshal
+	var cf configfile.ConfFile
+	err = json.Unmarshal(js, &cf)
+	if err != nil {
+		tlog.Fatal.Printf("Failed to unmarshal config file")
+		os.Exit(exitcodes.LoadConf)
+	}
+	if cf.Version != contentenc.CurrentVersion {
+		tlog.Fatal.Printf("Unsupported on-disk format %d", cf.Version)
+		os.Exit(exitcodes.LoadConf)
+	}
+	// Pretty-print
+	fmt.Printf("Creator:      %s\n", cf.Creator)
+	fmt.Printf("FeatureFlags: %s\n", strings.Join(cf.FeatureFlags, " "))
+	fmt.Printf("EncryptedKey: %dB\n", len(cf.EncryptedKey))
+	s := cf.ScryptObject
+	fmt.Printf("ScryptObject: Salt=%dB N=%d R=%d P=%d KeyLen=%d\n",
+		len(s.Salt), s.N, s.R, s.P, s.KeyLen)
+	os.Exit(0)
+}