main: accept "-o" at the front AND at the end

Moving "-o" to the end broke a third-party app, SiriKali.
Breaking your users is bad, so let's accept "-o" anywhere.

cli_args.go

@@ -32,22 +32,39 @@ var flagSet *flag.FlagSet
 // prefixOArgs transform options passed via "-o foo,bar" into regular options
 // like "-foo -bar" and prefixes them to the command line.
 func prefixOArgs(osArgs []string) []string {
-	l := len(osArgs)
 	// Need at least 3, example: gocryptfs -o foo,bar
-	if l < 3 {
+	if len(osArgs) < 3 {
 		return osArgs
 	}
-	if osArgs[l-2] != "-o" {
-		return osArgs
+	// Find and extract "-o foo,bar"
+	var otherArgs, oOpts []string
+	for i := 1; i < len(osArgs); i++ {
+		if osArgs[i] == "-o" {
+			// Last argument?
+			if i+1 >= len(osArgs) {
+				tlog.Fatal.Printf("The \"-o\" option requires an argument")
+				os.Exit(ErrExitUsage)
+			}
+			oOpts = strings.Split(osArgs[i+1], ",")
+			// Skip over the arguments to "-o"
+			i++
+		} else if strings.HasPrefix(osArgs[i], "-o=") {
+			oOpts = strings.Split(osArgs[i][3:], ",")
+		} else {
+			otherArgs = append(otherArgs, osArgs[i])
+		}
 	}
-	oOpts := strings.Split(osArgs[l-1], ",")
-	osArgs = osArgs[:l-2]
+	// Start with program name
 	newArgs := []string{osArgs[0]}
 	// Add options from "-o"
-	for _, a := range oOpts {
-		newArgs = append(newArgs, "-"+a)
+	for _, o := range oOpts {
+		if o == "" {
+			continue
+		}
+		newArgs = append(newArgs, "-"+o)
 	}
-	newArgs = append(newArgs, osArgs[1:]...)
+	// Add other arguments
+	newArgs = append(newArgs, otherArgs...)
 	return newArgs
 }
 

cli_args_test.go

@@ -38,15 +38,24 @@ func TestPrefixOArgs(t *testing.T) {
 			i: []string{"gocryptfs", "foo", "bar", "-o", "a,b,xxxxx"},
 			o: []string{"gocryptfs", "-a", "-b", "-xxxxx", "foo", "bar"},
 		},
+		testcase{
+			i: []string{"gocryptfs", "foo", "bar", "-d", "-o=a,b,xxxxx"},
+			o: []string{"gocryptfs", "-a", "-b", "-xxxxx", "foo", "bar", "-d"},
+		},
 		testcase{
 			i: []string{"gocryptfs", "foo", "bar", "-oooo", "a,b,xxxxx"},
 			o: []string{"gocryptfs", "foo", "bar", "-oooo", "a,b,xxxxx"},
 		},
+		// https://github.com/mhogomchungu/sirikali/blob/a36d91d3e39f0c1eb9a79680ed6c28ddb6568fa8/src/siritask.cpp#L192
+		testcase{
+			i: []string{"gocryptfs", "-o", "rw", "--config", "fff", "ccc", "mmm"},
+			o: []string{"gocryptfs", "-rw", "--config", "fff", "ccc", "mmm"},
+		},
 	}
 	for _, tc := range testcases {
 		o := prefixOArgs(tc.i)
 		if !reflect.DeepEqual(o, tc.o) {
-			t.Errorf("\n   i=%q\nwant=%q\n got=%q", tc.i, tc.o, o)
+			t.Errorf("\n  in=%q\nwant=%q\n got=%q", tc.i, tc.o, o)
 		}
 	}
 }