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>

4 files changed, 135 insertions, 4 deletions

diff --git a/docs/source/markdown/podman-create.1.md b/docs/source/markdown/podman-create.1.md
index 0c48f105e..4a20e4e45 100644
--- a/docs/source/markdown/podman-create.1.md
+++ b/docs/source/markdown/podman-create.1.md
@@ -595,6 +595,8 @@ Current supported mount TYPEs are **bind**, **volume**, **image**, **tmpfs** and
 
        type=bind,src=/path/on/host,dst=/path/in/container,relabel=shared
 
+       type=bind,src=/path/on/host,dst=/path/in/container,relabel=shared,U=true
+
        type=volume,source=vol1,destination=/path/in/container,ro=true
 
        type=tmpfs,tmpfs-size=512M,destination=/path/in/container
@@ -613,6 +615,8 @@ Current supported mount TYPEs are **bind**, **volume**, **image**, **tmpfs** and
 
 	      · ro, readonly: true or false (default).
 
+        . U, chown: true or false (default). Change recursively the owner and group of the source volume based on the UID and GID of the container.
+
        Options specific to image:
 
 	      · rw, readwrite: true or false (default).
@@ -627,6 +631,8 @@ Current supported mount TYPEs are **bind**, **volume**, **image**, **tmpfs** and
 
 	      . relabel: shared, private.
 
+        . U, chown: true or false (default). Change recursively the owner and group of the source volume based on the UID and GID of the container.
+
        Options specific to tmpfs:
 
 	      · ro, readonly: true or false (default).
@@ -639,6 +645,7 @@ Current supported mount TYPEs are **bind**, **volume**, **image**, **tmpfs** and
 
 	      · notmpcopyup: Disable copying files from the image to the tmpfs.
 
+        . U, chown: true or false (default). Change recursively the owner and group of the source volume based on the UID and GID of the container.
 
 #### **--name**=*name*
 
diff --git a/docs/source/markdown/podman-run.1.md b/docs/source/markdown/podman-run.1.md
index 7b6a56fc6..7a2e09dab 100644
--- a/docs/source/markdown/podman-run.1.md
+++ b/docs/source/markdown/podman-run.1.md
@@ -615,6 +615,8 @@ Current supported mount TYPEs are **bind**, **volume**, **image**, **tmpfs** and
 
        type=bind,src=/path/on/host,dst=/path/in/container,relabel=shared
 
+       type=bind,src=/path/on/host,dst=/path/in/container,relabel=shared,U=true
+
        type=volume,source=vol1,destination=/path/in/container,ro=true
 
        type=tmpfs,tmpfs-size=512M,destination=/path/in/container
@@ -633,6 +635,8 @@ Current supported mount TYPEs are **bind**, **volume**, **image**, **tmpfs** and
 
 	      · ro, readonly: true or false (default).
 
+        . U, chown: true or false (default). Change recursively the owner and group of the source volume based on the UID and GID of the container.
+
        Options specific to image:
 
 	      · rw, readwrite: true or false (default).
@@ -647,6 +651,8 @@ Current supported mount TYPEs are **bind**, **volume**, **image**, **tmpfs** and
 
 	      . relabel: shared, private.
 
+        . U, chown: true or false (default). Change recursively the owner and group of the source volume based on the UID and GID of the container.
+
        Options specific to tmpfs:
 
 	      · ro, readonly: true or false (default).
@@ -659,6 +665,8 @@ Current supported mount TYPEs are **bind**, **volume**, **image**, **tmpfs** and
 
 	      · notmpcopyup: Disable copying files from the image to the tmpfs.
 
+        . U, chown: true or false (default). Change recursively the owner and group of the source volume based on the UID and GID of the container.
+
 #### **--name**=*name*
 
 Assign a name to the container.
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
+}
diff --git a/test/e2e/run_volume_test.go b/test/e2e/run_volume_test.go
index 59937b6c0..690c53de6 100644
--- a/test/e2e/run_volume_test.go
+++ b/test/e2e/run_volume_test.go
@@ -614,7 +614,7 @@ VOLUME /test/`, ALPINE)
 		Expect(len(session.OutputToStringArray())).To(Equal(2))
 	})
 
-	It("podman run with U volume flag", func() {
+	It("podman run with --volume and U flag", func() {
 		SkipIfRemote("Overlay volumes only work locally")
 
 		u, err := user.Current()
@@ -665,6 +665,65 @@ VOLUME /test/`, ALPINE)
 		Expect(found).Should(BeTrue())
 	})
 
+	It("podman run with --mount and U flag", func() {
+		u, err := user.Current()
+		Expect(err).To(BeNil())
+		name := u.Username
+		if name == "root" {
+			name = "containers"
+		}
+
+		content, err := ioutil.ReadFile("/etc/subuid")
+		if err != nil {
+			Skip("cannot read /etc/subuid")
+		}
+
+		if !strings.Contains(string(content), name) {
+			Skip("cannot find mappings for the current user")
+		}
+
+		mountPath := filepath.Join(podmanTest.TempDir, "foo")
+		os.Mkdir(mountPath, 0755)
+
+		// false bind mount
+		vol := "type=bind,src=" + mountPath + ",dst=" + dest + ",U=false"
+		session := podmanTest.Podman([]string{"run", "--rm", "--user", "888:888", "--mount", vol, ALPINE, "stat", "-c", "%u:%g", dest})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		Expect(session.OutputToString()).ShouldNot(Equal("888:888"))
+
+		// invalid bind mount
+		vol = "type=bind,src=" + mountPath + ",dst=" + dest + ",U=invalid"
+		session = podmanTest.Podman([]string{"run", "--rm", "--user", "888:888", "--mount", vol, ALPINE, "stat", "-c", "%u:%g", dest})
+		session.WaitWithDefaultTimeout()
+		Expect(session).To(ExitWithError())
+
+		// true bind mount
+		vol = "type=bind,src=" + mountPath + ",dst=" + dest + ",U=true"
+		session = podmanTest.Podman([]string{"run", "--rm", "--user", "888:888", "--mount", vol, ALPINE, "stat", "-c", "%u:%g", dest})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		Expect(session.OutputToString()).Should(Equal("888:888"))
+
+		// tmpfs mount
+		vol = "type=tmpfs," + "dst=" + dest + ",chown"
+		session = podmanTest.Podman([]string{"run", "--rm", "--user", "888:888", "--mount", vol, ALPINE, "stat", "-c", "%u:%g", dest})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		Expect(session.OutputToString()).Should(Equal("888:888"))
+
+		// named volume mount
+		namedVolume := podmanTest.Podman([]string{"volume", "create", "foo"})
+		namedVolume.WaitWithDefaultTimeout()
+		Expect(namedVolume).Should(Exit(0))
+
+		vol = "type=volume,src=foo,dst=" + dest + ",chown=true"
+		session = podmanTest.Podman([]string{"run", "--rm", "--user", "888:888", "--mount", vol, ALPINE, "stat", "-c", "%u:%g", dest})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		Expect(session.OutputToString()).Should(Equal("888:888"))
+	})
+
 	It("volume permissions after run", func() {
 		imgName := "testimg"
 		dockerfile := fmt.Sprintf(`FROM %s