Fix machine volumes with long path and paths with dashes

AppleHV accepts a max 36 bytes for mount tags. Instead of using the fully qualified path for the mount tag, SHA256 the path, and truncate the shasum to 36 bytes.
Also correctly escape dashes in mounted paths.

Signed-off-by: Ashley Cui <acui@redhat.com>

pkg/machine/apple/apple.go

@@ -96,19 +96,19 @@ func GenerateSystemDFilesForVirtiofsMounts(mounts []machine.VirtIoFs) ([]ignitio
 
 		virtiofsAutomount := ignition.Unit{
 			Enabled:  ignition.BoolToPtr(true),
-			Name:     fmt.Sprintf("%s.automount", mnt.Tag),
+			Name:     fmt.Sprintf("%s.automount", parser.PathEscape(mnt.Target)),
-			Contents: ignition.StrToPtr(fmt.Sprintf(autoMountUnitFile, mnt.Target, mnt.Target)),
+			Contents: ignition.StrToPtr(fmt.Sprintf(autoMountUnitFile, mnt.Tag, mnt.Target)),
 		}
 		virtiofsMount := ignition.Unit{
 			Enabled:  ignition.BoolToPtr(true),
-			Name:     fmt.Sprintf("%s.mount", mnt.Tag),
+			Name:     fmt.Sprintf("%s.mount", parser.PathEscape(mnt.Target)),
 			Contents: ignition.StrToPtr(fmt.Sprintf(mountUnitFile, mnt.Tag, mnt.Target)),
 		}
 
 		// This "unit" simulates something like systemctl enable virtiofs-mount-prepare@
 		enablePrep := ignition.Unit{
 			Enabled: ignition.BoolToPtr(true),
-			Name:    fmt.Sprintf("virtiofs-mount-prepare@%s.service", mnt.Tag),
+			Name:    fmt.Sprintf("virtiofs-mount-prepare@%s.service", parser.PathEscape(mnt.Target)),
 		}
 
 		unitFiles = append(unitFiles, virtiofsAutomount, virtiofsMount, enablePrep)

pkg/machine/e2e/init_test.go

@@ -207,7 +207,8 @@ var _ = Describe("podman machine init", func() {
 		Expect(err).ToNot(HaveOccurred())
 		_, err = os.CreateTemp(tmpDir, "example")
 		Expect(err).ToNot(HaveOccurred())
-		mount := tmpDir + ":/testmountdir"
+		// Test long target path, see https://github.com/containers/podman/issues/22226
+		mount := tmpDir + ":/very-long-test-mount-dir-path-more-than-thirty-six-bytes"
 		defer func() { _ = utils.GuardedRemoveAll(tmpDir) }()
 
 		name := randomString()
@@ -217,7 +218,7 @@ var _ = Describe("podman machine init", func() {
 		Expect(session).To(Exit(0))
 
 		ssh := sshMachine{}
-		sshSession, err := mb.setName(name).setCmd(ssh.withSSHCommand([]string{"ls /testmountdir"})).run()
+		sshSession, err := mb.setName(name).setCmd(ssh.withSSHCommand([]string{"ls /very-long-test-mount-dir-path-more-than-thirty-six-bytes"})).run()
 		Expect(err).ToNot(HaveOccurred())
 		Expect(sshSession).To(Exit(0))
 		Expect(sshSession.outputToString()).To(ContainSubstring("example"))

pkg/machine/volumes.go

@@ -1,7 +1,8 @@
 package machine
 
 import (
-	"strings"
+	"crypto/sha256"
+	"encoding/hex"
 
 	"github.com/containers/podman/v5/pkg/machine/vmconfigs"
 )
@@ -29,14 +30,13 @@ func (v VirtIoFs) Kind() string {
 	return string(VirtIOFsVk)
 }
 
-// unitName is the fq path where /'s are replaced with -'s
+// generateTag generates a tag for VirtIOFs mounts.
-func (v VirtIoFs) unitName() string {
+// AppleHV requires tags to be 36 bytes or fewer.
-	// delete the leading -
+// SHA256 the path, then truncate to 36 bytes
-	unit := strings.ReplaceAll(v.Target, "/", "-")
+func (v VirtIoFs) generateTag() string {
-	if strings.HasPrefix(unit, "-") {
+	sum := sha256.Sum256([]byte(v.Target))
-		return unit[1:]
+	stringSum := hex.EncodeToString(sum[:])
-	}
+	return stringSum[:36]
-	return unit
 }
 
 func (v VirtIoFs) ToMount() vmconfigs.Mount {
@@ -58,7 +58,7 @@ func NewVirtIoFsMount(src, target string, readOnly bool) VirtIoFs {
 		Source:   src,
 		Target:   target,
 	}
-	vfs.Tag = vfs.unitName()
+	vfs.Tag = vfs.generateTag()
 	return vfs
 }
 

pkg/systemd/parser/split.go

@@ -428,13 +428,17 @@ func splitString(s string, separators string, flags SplitFlags) ([]string, error
 	return splitStringAppend(make([]string, 0), s, separators, flags)
 }
 
-func charNeedEscape(c rune) bool {
+func charNeedEscape(c rune, isPath bool) bool {
 	if c > 128 {
 		return false /* unicode is ok */
 	}
 
+	pathRune := (isPath && c == '-') ||
+		(isPath && c == '/')
+
 	return unicode.IsSpace(c) ||
 		unicode.IsControl(c) ||
+		pathRune ||
 		c == '"' ||
 		c == '\'' ||
 		c == '\\'
@@ -442,18 +446,22 @@ func charNeedEscape(c rune) bool {
 
 func wordNeedEscape(word string) bool {
 	for _, c := range word {
-		if charNeedEscape(c) {
+		if charNeedEscape(c, false) {
 			return true
 		}
 	}
-
 	return false
 }
 
 func appendEscapeWord(escaped *strings.Builder, word string) {
 	escaped.WriteRune('"')
-	for _, c := range word {
+	escapeString(escaped, word, false)
-		if charNeedEscape(c) {
+	escaped.WriteRune('"')
+}
+
+func escapeString(escaped *strings.Builder, word string, isPath bool) {
+	for i, c := range word {
+		if charNeedEscape(c, isPath) {
 			switch c {
 			case '\a':
 				escaped.WriteString("\\a")
@@ -477,6 +485,10 @@ func appendEscapeWord(escaped *strings.Builder, word string) {
 				escaped.WriteString("\\\"")
 			case '\'':
 				escaped.WriteString("'")
+			case '/':
+				if isPath && i != 0 {
+					escaped.WriteString("-")
+				}
 			default:
 				escaped.WriteString(fmt.Sprintf("\\x%.2x", c))
 			}
@@ -484,7 +496,6 @@ func appendEscapeWord(escaped *strings.Builder, word string) {
 			escaped.WriteRune(c)
 		}
 	}
-	escaped.WriteRune('"')
 }
 
 func escapeWords(words []string) string {
@@ -500,6 +511,5 @@ func escapeWords(words []string) string {
 			escaped.WriteString(word)
 		}
 	}
-
 	return escaped.String()
 }

pkg/systemd/parser/unitfile.go

@@ -932,3 +932,9 @@ func (f *UnitFile) GetTemplateParts() (string, string) {
 	}
 	return parts[0] + "@" + ext, parts[1]
 }
+
+func PathEscape(path string) string {
+	var escaped strings.Builder
+	escapeString(&escaped, path, true)
+	return escaped.String()
+}