readpassword: bubble up errors instead of exiting the process

This allows cleanups to happen in the caller, like removing
the control socket.

Fixes https://github.com/rfjakob/gocryptfs/issues/634

1 files changed, 14 insertions, 14 deletions

diff --git a/internal/readpassword/passfile.go b/internal/readpassword/passfile.go
index 29fde6c..60902b7 100644
--- a/internal/readpassword/passfile.go
+++ b/internal/readpassword/passfile.go
@@ -2,28 +2,31 @@ package readpassword
 
 import (
 	"bytes"
+	"fmt"
 	"os"
 
-	"github.com/rfjakob/gocryptfs/v2/internal/exitcodes"
 	"github.com/rfjakob/gocryptfs/v2/internal/tlog"
 )
 
 // readPassFileConcatenate reads the first line from each file name and
 // concatenates the results. The result does not contain any newlines.
-func readPassFileConcatenate(passfileSlice []string) (result []byte) {
+func readPassFileConcatenate(passfileSlice []string) (result []byte, err error) {
 	for _, e := range passfileSlice {
-		result = append(result, readPassFile(e)...)
+		add, err := readPassFile(e)
+		if err != nil {
+			return nil, err
+		}
+		result = append(result, add...)
 	}
-	return result
+	return result, nil
 }
 
 // readPassFile reads the first line from the passed file name.
-func readPassFile(passfile string) []byte {
+func readPassFile(passfile string) ([]byte, error) {
 	tlog.Info.Printf("passfile: reading from file %q", passfile)
 	f, err := os.Open(passfile)
 	if err != nil {
-		tlog.Fatal.Printf("fatal: passfile: could not open %q: %v", passfile, err)
-		os.Exit(exitcodes.ReadPassword)
+		return nil, fmt.Errorf("fatal: passfile: could not open %q: %v", passfile, err)
 	}
 	defer f.Close()
 	// +1 for an optional trailing newline,
@@ -31,23 +34,20 @@ func readPassFile(passfile string) []byte {
 	buf := make([]byte, maxPasswordLen+2)
 	n, err := f.Read(buf)
 	if err != nil {
-		tlog.Fatal.Printf("fatal: passfile: could not read from %q: %v", passfile, err)
-		os.Exit(exitcodes.ReadPassword)
+		return nil, fmt.Errorf("fatal: passfile: could not read from %q: %v", passfile, err)
 	}
 	buf = buf[:n]
 	// Split into first line and "trailing garbage"
 	lines := bytes.SplitN(buf, []byte("\n"), 2)
 	if len(lines[0]) == 0 {
-		tlog.Fatal.Printf("fatal: passfile: empty first line in %q", passfile)
-		os.Exit(exitcodes.ReadPassword)
+		return nil, fmt.Errorf("fatal: passfile: empty first line in %q", passfile)
 	}
 	if len(lines[0]) > maxPasswordLen {
-		tlog.Fatal.Printf("fatal: passfile: max password length (%d bytes) exceeded", maxPasswordLen)
-		os.Exit(exitcodes.ReadPassword)
+		return nil, fmt.Errorf("fatal: passfile: max password length (%d bytes) exceeded", maxPasswordLen)
 	}
 	if len(lines) > 1 && len(lines[1]) > 0 {
 		tlog.Warn.Printf("warning: passfile: ignoring trailing garbage (%d bytes) after first line",
 			len(lines[1]))
 	}
-	return lines[0]
+	return lines[0], nil
 }