Add support for :U flag with --mount option

The :U flag can be used to change the ownership of source volumes based on
the UID, GID of the container. This is only supported by the --volume option,
this will allow to use --mount option as well.

Signed-off-by: Eduardo Vega <edvegavalerio@gmail.com>

1 files changed, 60 insertions, 3 deletions

diff --git a/pkg/specgenutil/volumes.go b/pkg/specgenutil/volumes.go
index 0ed08198f..3ce96164f 100644
--- a/pkg/specgenutil/volumes.go
+++ b/pkg/specgenutil/volumes.go
@@ -243,7 +243,7 @@ func getBindMount(args []string) (spec.Mount, error) {
 		Type: define.TypeBind,
 	}
 
-	var setSource, setDest, setRORW, setSuid, setDev, setExec, setRelabel bool
+	var setSource, setDest, setRORW, setSuid, setDev, setExec, setRelabel, setOwnership bool
 
 	for _, val := range args {
 		kv := strings.SplitN(val, "=", 2)
@@ -343,6 +343,18 @@ func getBindMount(args []string) (spec.Mount, error) {
 			default:
 				return newMount, errors.Wrapf(util.ErrBadMntOption, "%s mount option must be 'private' or 'shared'", kv[0])
 			}
+		case "U", "chown":
+			if setOwnership {
+				return newMount, errors.Wrapf(optionArgError, "cannot pass 'U' or 'chown' option more than once")
+			}
+			ok, err := validChownFlag(val)
+			if err != nil {
+				return newMount, err
+			}
+			if ok {
+				newMount.Options = append(newMount.Options, "U")
+			}
+			setOwnership = true
 		case "consistency":
 			// Often used on MACs and mistakenly on Linux platforms.
 			// Since Docker ignores this option so shall we.
@@ -375,7 +387,7 @@ func getTmpfsMount(args []string) (spec.Mount, error) {
 		Source: define.TypeTmpfs,
 	}
 
-	var setDest, setRORW, setSuid, setDev, setExec, setTmpcopyup bool
+	var setDest, setRORW, setSuid, setDev, setExec, setTmpcopyup, setOwnership bool
 
 	for _, val := range args {
 		kv := strings.SplitN(val, "=", 2)
@@ -431,6 +443,18 @@ func getTmpfsMount(args []string) (spec.Mount, error) {
 			}
 			newMount.Destination = filepath.Clean(kv[1])
 			setDest = true
+		case "U", "chown":
+			if setOwnership {
+				return newMount, errors.Wrapf(optionArgError, "cannot pass 'U' or 'chown' option more than once")
+			}
+			ok, err := validChownFlag(val)
+			if err != nil {
+				return newMount, err
+			}
+			if ok {
+				newMount.Options = append(newMount.Options, "U")
+			}
+			setOwnership = true
 		case "consistency":
 			// Often used on MACs and mistakenly on Linux platforms.
 			// Since Docker ignores this option so shall we.
@@ -486,7 +510,7 @@ func getDevptsMount(args []string) (spec.Mount, error) {
 func getNamedVolume(args []string) (*specgen.NamedVolume, error) {
 	newVolume := new(specgen.NamedVolume)
 
-	var setSource, setDest, setRORW, setSuid, setDev, setExec bool
+	var setSource, setDest, setRORW, setSuid, setDev, setExec, setOwnership bool
 
 	for _, val := range args {
 		kv := strings.SplitN(val, "=", 2)
@@ -532,6 +556,18 @@ func getNamedVolume(args []string) (*specgen.NamedVolume, error) {
 			}
 			newVolume.Dest = filepath.Clean(kv[1])
 			setDest = true
+		case "U", "chown":
+			if setOwnership {
+				return newVolume, errors.Wrapf(optionArgError, "cannot pass 'U' or 'chown' option more than once")
+			}
+			ok, err := validChownFlag(val)
+			if err != nil {
+				return newVolume, err
+			}
+			if ok {
+				newVolume.Options = append(newVolume.Options, "U")
+			}
+			setOwnership = true
 		case "consistency":
 			// Often used on MACs and mistakenly on Linux platforms.
 			// Since Docker ignores this option so shall we.
@@ -628,3 +664,24 @@ func getTmpfsMounts(tmpfsFlag []string) (map[string]spec.Mount, error) {
 	}
 	return m, nil
 }
+
+// validChownFlag ensures that the U or chown flag is correctly used
+func validChownFlag(flag string) (bool, error) {
+	kv := strings.SplitN(flag, "=", 2)
+	switch len(kv) {
+	case 1:
+	case 2:
+		// U=[true|false]
+		switch strings.ToLower(kv[1]) {
+		case "true":
+		case "false":
+			return false, nil
+		default:
+			return false, errors.Wrapf(optionArgError, "'U' or 'chown' must be set to true or false, instead received %q", kv[1])
+		}
+	default:
+		return false, errors.Wrapf(optionArgError, "badly formatted option %q", flag)
+	}
+
+	return true, nil
+}