Document containers.conf settings for remote connections

Currently we don't document which end of the podman-remote client server
operations uses the containers.conf.  This PR begins documenting this
and then testing to make sure the defaults follow the rules.

Fixes: https://github.com/containers/podman/issues/7657

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

1 files changed, 149 insertions, 0 deletions

diff --git a/pkg/specgen/volumes.go b/pkg/specgen/volumes.go
new file mode 100644
index 000000000..1178f9960
--- /dev/null
+++ b/pkg/specgen/volumes.go
@@ -0,0 +1,149 @@
+package specgen
+
+import (
+	"path/filepath"
+	"strings"
+
+	"github.com/containers/buildah/pkg/parse"
+	spec "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+// NamedVolume holds information about a named volume that will be mounted into
+// the container.
+type NamedVolume struct {
+	// Name is the name of the named volume to be mounted. May be empty.
+	// If empty, a new named volume with a pseudorandomly generated name
+	// will be mounted at the given destination.
+	Name string
+	// Destination to mount the named volume within the container. Must be
+	// an absolute path. Path will be created if it does not exist.
+	Dest string
+	// Options are options that the named volume will be mounted with.
+	Options []string
+}
+
+// OverlayVolume holds information about a overlay volume that will be mounted into
+// the container.
+type OverlayVolume struct {
+	// Destination is the absolute path where the mount will be placed in the container.
+	Destination string `json:"destination"`
+	// Source specifies the source path of the mount.
+	Source string `json:"source,omitempty"`
+}
+
+// ImageVolume is a volume based on a container image.  The container image is
+// first mounted on the host and is then bind-mounted into the container.  An
+// ImageVolume is always mounted read only.
+type ImageVolume struct {
+	// Source is the source of the image volume.  The image can be referred
+	// to by name and by ID.
+	Source string
+	// Destination is the absolute path of the mount in the container.
+	Destination string
+	// ReadWrite sets the volume writable.
+	ReadWrite bool
+}
+
+// GenVolumeMounts parses user input into mounts, volumes and overlay volumes
+func GenVolumeMounts(volumeFlag []string) (map[string]spec.Mount, map[string]*NamedVolume, map[string]*OverlayVolume, error) {
+	errDuplicateDest := errors.Errorf("duplicate mount destination")
+
+	mounts := make(map[string]spec.Mount)
+	volumes := make(map[string]*NamedVolume)
+	overlayVolumes := make(map[string]*OverlayVolume)
+
+	volumeFormatErr := errors.Errorf("incorrect volume format, should be [host-dir:]ctr-dir[:option]")
+
+	for _, vol := range volumeFlag {
+		var (
+			options []string
+			src     string
+			dest    string
+			err     error
+		)
+
+		splitVol := strings.Split(vol, ":")
+		if len(splitVol) > 3 {
+			return nil, nil, nil, errors.Wrapf(volumeFormatErr, vol)
+		}
+
+		src = splitVol[0]
+		if len(splitVol) == 1 {
+			// This is an anonymous named volume. Only thing given
+			// is destination.
+			// Name/source will be blank, and populated by libpod.
+			src = ""
+			dest = splitVol[0]
+		} else if len(splitVol) > 1 {
+			dest = splitVol[1]
+		}
+		if len(splitVol) > 2 {
+			if options, err = parse.ValidateVolumeOpts(strings.Split(splitVol[2], ",")); err != nil {
+				return nil, nil, nil, err
+			}
+		}
+
+		// Do not check source dir for anonymous volumes
+		if len(splitVol) > 1 {
+			if err := parse.ValidateVolumeHostDir(src); err != nil {
+				return nil, nil, nil, err
+			}
+		}
+		if err := parse.ValidateVolumeCtrDir(dest); err != nil {
+			return nil, nil, nil, err
+		}
+
+		cleanDest := filepath.Clean(dest)
+
+		if strings.HasPrefix(src, "/") || strings.HasPrefix(src, ".") {
+			// This is not a named volume
+			overlayFlag := false
+			for _, o := range options {
+				if o == "O" {
+					overlayFlag = true
+					if len(options) > 1 {
+						return nil, nil, nil, errors.New("can't use 'O' with other options")
+					}
+				}
+			}
+			if overlayFlag {
+				// This is a overlay volume
+				newOverlayVol := new(OverlayVolume)
+				newOverlayVol.Destination = cleanDest
+				newOverlayVol.Source = src
+				if _, ok := overlayVolumes[newOverlayVol.Destination]; ok {
+					return nil, nil, nil, errors.Wrapf(errDuplicateDest, newOverlayVol.Destination)
+				}
+				overlayVolumes[newOverlayVol.Destination] = newOverlayVol
+			} else {
+				newMount := spec.Mount{
+					Destination: cleanDest,
+					Type:        "bind",
+					Source:      src,
+					Options:     options,
+				}
+				if _, ok := mounts[newMount.Destination]; ok {
+					return nil, nil, nil, errors.Wrapf(errDuplicateDest, newMount.Destination)
+				}
+				mounts[newMount.Destination] = newMount
+			}
+		} else {
+			// This is a named volume
+			newNamedVol := new(NamedVolume)
+			newNamedVol.Name = src
+			newNamedVol.Dest = cleanDest
+			newNamedVol.Options = options
+
+			if _, ok := volumes[newNamedVol.Dest]; ok {
+				return nil, nil, nil, errors.Wrapf(errDuplicateDest, newNamedVol.Dest)
+			}
+			volumes[newNamedVol.Dest] = newNamedVol
+		}
+
+		logrus.Debugf("User mount %s:%s options %v", src, dest, options)
+	}
+
+	return mounts, volumes, overlayVolumes, nil
+}