linux/udev: fix udevadm info parser to not be fatal

The current parser returns an error when it encounters newer prefix
values in the output of udevadm info.  Anytime a system upgrades to
a newer release, there is a change new fields will be present preventing
disko from producing any output.

- Update and document prefixes defined in systemd v255
- Replace error with an warning output
- make sure we have two tokens when parsing udevadm info output

Signed-off-by: Ryan Harper <[email protected]>

linux/util.go

@@ -48,15 +48,50 @@ func parseUdevInfo(out []byte, info *disko.UdevInfo) error {
 		}
 
 		toks = bytes.SplitN(line, []byte(": "), 2)
-		payload = string(toks[1])
 
+		if len(toks) != 2 {
+			log.Printf("parseUdevInfo: ignoring unparsable line %q\n", line)
+			continue
+		}
+
+		payload = string(toks[1])
 		switch toks[0][0] {
 		case 'P':
+			// Device path in /sys/
 			info.SysPath = payload
+		case 'M':
+			// Device name in /sys/ (i.e. the last component of "P:")
+			continue
+		case 'R':
+			// Device number in /sys/ (i.e. the numeric suffix of the last component of "P:")
+			continue
+		case 'U':
+			// Kernel subsystem
+			continue
+		case 'T':
+			// Kernel device type with subsystem
+			continue
+		case 'D':
+			// Kernel device node major/minor
+			continue
+		case 'I':
+			// Network interface index
+			continue
 		case 'N':
+			// Kernel device node name
 			info.Name = payload
+		case 'L':
+			// Device node symlink priority
+			continue
 		case 'S':
+			// Device node symlink
 			info.Symlinks = append(info.Symlinks, strings.Split(payload, " ")...)
+		case 'Q':
+			// Block device sequence number (DISKSEQ)
+			continue
+		case 'V':
+			// Attached driver
+			continue
 		case 'E':
 			kv := strings.SplitN(payload, "=", 2)
 			// use of Unquote is to decode \x20, \x2f and friends.
@@ -68,10 +103,8 @@ func parseUdevInfo(out []byte, info *disko.UdevInfo) error {
 			}
 
 			info.Properties[kv[0]] = strings.TrimSpace(s)
-		case 'L':
-			// a 'devlink priority'. skip for now.
 		default:
-			return fmt.Errorf("error parsing line: (%s)", line)
+			log.Printf("parseUdevInfo: ignoring unknown udevadm info prefix %q in %q\n", toks[0][0], line)
 		}
 	}
 

linux/util_test.go

@@ -12,6 +12,7 @@ import (
 func TestParseUdevInfo(t *testing.T) {
 	data := []byte(`P: /devices/virtual/block/dm-0
 N: dm-0
+M: dm-0
 S: disk/by-id/dm-name-nvme0n1p6_crypt
 S: disk/by-id/dm-uuid-CRYPT-LUKS1-b174c64e7a714359a8b56b79fb66e92b-nvme0n1p6_crypt
 S: disk/by-uuid/25df9069-80c7-46f4-a47c-305613c2cb6b
@@ -49,6 +50,7 @@ E: DEVNAME=/dev/dm-0
 func TestParseUdevInfo2(t *testing.T) {
 	data := []byte(`P: /devices/pci0000:00/..../block/sda
 N: sda
+M: sda
 S: disk/by-id/scsi-35000c500a0d8963f
 S: disk/by-id/wwn-0x5000c500a0d8963f
 S: disk/by-path/pci-0000:05:00.0-scsi-0:0:8:0