podman cp: fix copying to a non-existent dir

Copy is full of perils.  Some of them are the nuances when copying
directories.  Who would have thought that
 * cp dir   foo
 * cp dir/  foo
 * cp dir/. foo
are all supposed to yield the same result when foo does not exist.

`podman cp` now supports all three notations, which required to massage
the front-end code in `cmd/podman` a bit.  The tests have been extended
and partially rewritten to test container->host and host->container
copy operations.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

2 files changed, 73 insertions, 38 deletions

diff --git a/cmd/podman/containers/cp.go b/cmd/podman/containers/cp.go
index 7a62d982c..27aacc6e5 100644
--- a/cmd/podman/containers/cp.go
+++ b/cmd/podman/containers/cp.go
@@ -160,6 +160,25 @@ func copyFromContainer(container string, containerPath string, hostPath string)
 		}
 	}
 
+	// If we copy a directory via the "." notation and the host path does
+	// not exist, we need to make sure that the destination on the host
+	// gets created; otherwise the contents of the source directory will be
+	// written to the destination's parent directory.
+	//
+	// While we could cut it short on the host and do create the directory
+	// ourselves, we would run into problems trying to that the other way
+	// around when copying into a container.  Instead, to keep both
+	// implementations symmetrical, we need to massage the code a bit to
+	// let Buildah's copier package create the destination.
+	//
+	// Hence, whenever "." is the source and the destination does not exist,
+	// we copy the source's parent and let the copier package create the
+	// destination via the Rename option.
+	containerTarget := containerInfo.LinkTarget
+	if hostInfoErr != nil && containerInfo.IsDir && strings.HasSuffix(containerTarget, ".") {
+		containerTarget = filepath.Dir(containerTarget)
+	}
+
 	reader, writer := io.Pipe()
 	hostCopy := func() error {
 		defer reader.Close()
@@ -193,10 +212,10 @@ func copyFromContainer(container string, containerPath string, hostPath string)
 			ChownFiles:    &idPair,
 			IgnoreDevices: true,
 		}
-		if !containerInfo.IsDir && (!hostInfo.IsDir || hostInfoErr != nil) {
+		if (!containerInfo.IsDir && !hostInfo.IsDir) || hostInfoErr != nil {
 			// If we're having a file-to-file copy, make sure to
 			// rename accordingly.
-			putOptions.Rename = map[string]string{filepath.Base(containerInfo.LinkTarget): hostBaseName}
+			putOptions.Rename = map[string]string{filepath.Base(containerTarget): hostBaseName}
 		}
 		dir := hostInfo.LinkTarget
 		if !hostInfo.IsDir {
@@ -210,7 +229,7 @@ func copyFromContainer(container string, containerPath string, hostPath string)
 
 	containerCopy := func() error {
 		defer writer.Close()
-		copyFunc, err := registry.ContainerEngine().ContainerCopyToArchive(registry.GetContext(), container, containerInfo.LinkTarget, writer)
+		copyFunc, err := registry.ContainerEngine().ContainerCopyToArchive(registry.GetContext(), container, containerTarget, writer)
 		if err != nil {
 			return err
 		}
@@ -278,6 +297,19 @@ func copyToContainer(container string, containerPath string, hostPath string) er
 		containerBaseName = filepath.Base(containerInfo.LinkTarget)
 	}
 
+	// If we copy a directory via the "." notation and the container path
+	// does not exist, we need to make sure that the destination on the
+	// container gets created; otherwise the contents of the source
+	// directory will be written to the destination's parent directory.
+	//
+	// Hence, whenever "." is the source and the destination does not
+	// exist, we copy the source's parent and let the copier package create
+	// the destination via the Rename option.
+	hostTarget := hostInfo.LinkTarget
+	if containerInfoErr != nil && hostInfo.IsDir && strings.HasSuffix(hostTarget, ".") {
+		hostTarget = filepath.Dir(hostTarget)
+	}
+
 	var stdinFile string
 	if isStdin {
 		if !containerInfo.IsDir {
@@ -318,15 +350,16 @@ func copyToContainer(container string, containerPath string, hostPath string) er
 		}
 
 		getOptions := buildahCopiah.GetOptions{
-			// Unless the specified points to ".", we want to copy the base directory.
-			KeepDirectoryNames: hostInfo.IsDir && filepath.Base(hostPath) != ".",
+			// Unless the specified path points to ".", we want to
+			// copy the base directory.
+			KeepDirectoryNames: hostInfo.IsDir && filepath.Base(hostTarget) != ".",
 		}
-		if !hostInfo.IsDir && (!containerInfo.IsDir || containerInfoErr != nil) {
+		if (!hostInfo.IsDir && !containerInfo.IsDir) || containerInfoErr != nil {
 			// If we're having a file-to-file copy, make sure to
 			// rename accordingly.
-			getOptions.Rename = map[string]string{filepath.Base(hostInfo.LinkTarget): containerBaseName}
+			getOptions.Rename = map[string]string{filepath.Base(hostTarget): containerBaseName}
 		}
-		if err := buildahCopiah.Get("/", "", getOptions, []string{hostInfo.LinkTarget}, writer); err != nil {
+		if err := buildahCopiah.Get("/", "", getOptions, []string{hostTarget}, writer); err != nil {
 			return errors.Wrap(err, "error copying from host")
 		}
 		return nil
diff --git a/test/system/065-cp.bats b/test/system/065-cp.bats
index 24d8a9fd1..43b21587f 100644
--- a/test/system/065-cp.bats
+++ b/test/system/065-cp.bats
@@ -192,20 +192,19 @@ load helpers
 
 
 @test "podman cp dir from host to container" {
-    dirname=dir-test
-    srcdir=$PODMAN_TMPDIR/$dirname
-    mkdir -p $srcdir
+    srcdir=$PODMAN_TMPDIR
+    mkdir -p $srcdir/dir/sub
     local -a randomcontent=(
         random-0-$(random_string 10)
         random-1-$(random_string 15)
     )
-    echo "${randomcontent[0]}" > $srcdir/hostfile0
-    echo "${randomcontent[1]}" > $srcdir/hostfile1
+    echo "${randomcontent[0]}" > $srcdir/dir/sub/hostfile0
+    echo "${randomcontent[1]}" > $srcdir/dir/sub/hostfile1
 
     # "." and "dir/." will copy the contents, so make sure that a dir ending
     # with dot is treated correctly.
-    mkdir -p $srcdir.
-    cp $srcdir/* $srcdir./
+    mkdir -p $srcdir/dir.
+    cp -r $srcdir/dir/* $srcdir/dir.
 
     run_podman run -d --name cpcontainer --workdir=/srv $IMAGE sleep infinity
     run_podman exec cpcontainer mkdir /srv/subdir
@@ -216,12 +215,15 @@ load helpers
 
     # format is: <source arg to cp (appended to srcdir)> | <destination arg to cp> | <full dest path> | <test name>
     tests="
-    | /        | /dir-test             | copy to root
- .  | /        | /dir-test.            | copy dotdir to root
- /  | /tmp     | /tmp/dir-test         | copy to tmp
- /. | /usr/    | /usr/                 | copy contents of dir to usr/
-    | .        | /srv/dir-test         | copy to workdir (rel path)
-    | subdir/. | /srv/subdir/dir-test  | copy to workdir subdir (rel path)
+ dir       | /        | /dir/sub     | copy dir  to root
+ dir.      | /        | /dir./sub    | copy dir. to root
+ dir/      | /tmp     | /tmp/dir/sub | copy dir/ to tmp
+ dir/.     | /usr/    | /usr/sub     | copy dir/. usr/
+ dir/sub   | .        | /srv/sub     | copy dir/sub to workdir (rel path)
+ dir/sub/. | subdir/. | /srv/subdir  | copy dir/sub/. to workdir subdir (rel path)
+ dir       | /newdir1 | /newdir1/sub | copy dir to newdir1
+ dir/      | /newdir2 | /newdir2/sub | copy dir/ to newdir2
+ dir/.     | /newdir3 | /newdir3/sub | copy dir/. to newdir3
 "
 
     # RUNNING container
@@ -230,12 +232,10 @@ load helpers
         if [[ $src == "''" ]];then
             unset src
         fi
-        run_podman cp $srcdir$src cpcontainer:$dest
-        run_podman exec cpcontainer ls $dest_fullname
-        run_podman exec cpcontainer cat $dest_fullname/hostfile0
-        is "$output" "${randomcontent[0]}" "$description (cp -> ctr:$dest)"
-        run_podman exec cpcontainer cat $dest_fullname/hostfile1
-        is "$output" "${randomcontent[1]}" "$description (cp -> ctr:$dest)"
+        run_podman cp $srcdir/$src cpcontainer:$dest
+        run_podman exec cpcontainer cat $dest_fullname/hostfile0 $dest_fullname/hostfile1
+        is "${lines[0]}" "${randomcontent[0]}" "$description (cp -> ctr:$dest)"
+        is "${lines[1]}" "${randomcontent[1]}" "$description (cp -> ctr:$dest)"
     done < <(parse_table "$tests")
     run_podman kill cpcontainer
     run_podman rm -f cpcontainer
@@ -247,7 +247,7 @@ load helpers
             unset src
         fi
         run_podman create --name cpcontainer --workdir=/srv $cpimage sleep infinity
-        run_podman cp $srcdir$src cpcontainer:$dest
+        run_podman cp $srcdir/$src cpcontainer:$dest
         run_podman start cpcontainer
         run_podman exec cpcontainer cat $dest_fullname/hostfile0 $dest_fullname/hostfile1
         is "${lines[0]}" "${randomcontent[0]}" "$description (cp -> ctr:$dest)"
@@ -280,17 +280,19 @@ load helpers
     run_podman commit -q cpcontainer
     cpimage="$output"
 
-    # format is: <source arg to cp (appended to /srv)> | <full dest path> | <test name>
+    # format is: <source arg to cp (appended to /srv)> | <dest> | <full dest path> | <test name>
     tests="
- /srv           | /srv/subdir | copy /srv
- /srv/          | /srv/subdir | copy /srv/
- /srv/.         | /subdir     | copy /srv/.
- /srv/subdir/.  |             | copy /srv/subdir/.
- /tmp/subdir.   | /subdir.    | copy /tmp/subdir.
+/srv          |         | /srv/subdir    | copy /srv
+/srv          | /newdir | /newdir/subdir | copy /srv to /newdir
+/srv/         |         | /srv/subdir    | copy /srv/
+/srv/.        |         | /subdir        | copy /srv/.
+/srv/.        | /newdir | /newdir/subdir | copy /srv/. to /newdir
+/srv/subdir/. |         |                | copy /srv/subdir/.
+/tmp/subdir.  |         | /subdir.       | copy /tmp/subdir.
 "
 
     # RUNNING container
-    while read src dest_fullname description; do
+    while read src dest dest_fullname description; do
         if [[ $src == "''" ]];then
             unset src
         fi
@@ -300,7 +302,7 @@ load helpers
         if [[ $dest_fullname == "''" ]];then
             unset dest_fullname
         fi
-        run_podman cp cpcontainer:$src $destdir
+        run_podman cp cpcontainer:$src $destdir$dest
         is "$(< $destdir$dest_fullname/containerfile0)" "${randomcontent[0]}" "$description"
         is "$(< $destdir$dest_fullname/containerfile1)" "${randomcontent[1]}" "$description"
         rm -rf $destdir/*
@@ -310,7 +312,7 @@ load helpers
 
     # CREATED container
     run_podman create --name cpcontainer --workdir=/srv $cpimage
-    while read src dest_fullname description; do
+    while read src dest dest_fullname description; do
         if [[ $src == "''" ]];then
             unset src
         fi
@@ -320,7 +322,7 @@ load helpers
         if [[ $dest_fullname == "''" ]];then
             unset dest_fullname
         fi
-        run_podman cp cpcontainer:$src $destdir
+        run_podman cp cpcontainer:$src $destdir$dest
         is "$(< $destdir$dest_fullname/containerfile0)" "${randomcontent[0]}" "$description"
         is "$(< $destdir$dest_fullname/containerfile1)" "${randomcontent[1]}" "$description"
         rm -rf $destdir/*