Add support for volumes-from, image volumes, init

This should complete Podmanv2's support for volume-related flags.
Most code was sourced from the old pkg/spec implementation with
modifications to account for the split between frontend flags
(volume, mount, tmpfs) and the backend flags implemented here.

Also enables tests for podman run with volumes

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

1 files changed, 303 insertions, 0 deletions

diff --git a/pkg/specgen/generate/storage.go b/pkg/specgen/generate/storage.go
index 7650e4e9a..241c9adeb 100644
--- a/pkg/specgen/generate/storage.go
+++ b/pkg/specgen/generate/storage.go
@@ -1,12 +1,20 @@
 package generate
 
 import (
+	"context"
+	"fmt"
+	"os"
 	"path"
 	"path/filepath"
 	"strings"
 
+	"github.com/containers/common/pkg/config"
+	"github.com/containers/libpod/libpod"
+	"github.com/containers/libpod/libpod/image"
+	"github.com/containers/libpod/pkg/specgen"
 	"github.com/containers/libpod/pkg/util"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
 
@@ -20,6 +28,301 @@ const (
 	TypeTmpfs = "tmpfs"
 )
 
+var (
+	errDuplicateDest = errors.Errorf("duplicate mount destination")
+)
+
+// Produce final mounts and named volumes for a container
+func finalizeMounts(ctx context.Context, s *specgen.SpecGenerator, rt *libpod.Runtime, rtc *config.Config, img *image.Image) ([]spec.Mount, []*specgen.NamedVolume, error) {
+	// Get image volumes
+	baseMounts, baseVolumes, err := getImageVolumes(ctx, img, s)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Get volumes-from mounts
+	volFromMounts, volFromVolumes, err := getVolumesFrom(s.VolumesFrom, rt)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Supercede from --volumes-from.
+	for dest, mount := range volFromMounts {
+		baseMounts[dest] = mount
+	}
+	for dest, volume := range volFromVolumes {
+		baseVolumes[dest] = volume
+	}
+
+	// Need to make map forms of specgen mounts/volumes.
+	unifiedMounts := map[string]spec.Mount{}
+	unifiedVolumes := map[string]*specgen.NamedVolume{}
+	for _, m := range s.Mounts {
+		if _, ok := unifiedMounts[m.Destination]; ok {
+			return nil, nil, errors.Wrapf(errDuplicateDest, "conflict in specified mounts - multiple mounts at %q", m.Destination)
+		}
+		unifiedMounts[m.Destination] = m
+	}
+	for _, v := range s.Volumes {
+		if _, ok := unifiedVolumes[v.Dest]; ok {
+			return nil, nil, errors.Wrapf(errDuplicateDest, "conflict in specified volumes - multiple volumes at %q", v.Dest)
+		}
+		unifiedVolumes[v.Dest] = v
+	}
+
+	// If requested, add container init binary
+	if s.Init {
+		initPath := s.InitPath
+		if initPath == "" && rtc != nil {
+			initPath = rtc.Engine.InitPath
+		}
+		initMount, err := addContainerInitBinary(s, initPath)
+		if err != nil {
+			return nil, nil, err
+		}
+		if _, ok := unifiedMounts[initMount.Destination]; ok {
+			return nil, nil, errors.Wrapf(errDuplicateDest, "conflict with mount added by --init to %q", initMount.Destination)
+		}
+		unifiedMounts[initMount.Destination] = initMount
+	}
+
+	// Before superseding, we need to find volume mounts which conflict with
+	// named volumes, and vice versa.
+	// We'll delete the conflicts here as we supersede.
+	for dest := range unifiedMounts {
+		if _, ok := baseVolumes[dest]; ok {
+			delete(baseVolumes, dest)
+		}
+	}
+	for dest := range unifiedVolumes {
+		if _, ok := baseMounts[dest]; ok {
+			delete(baseMounts, dest)
+		}
+	}
+
+	// Supersede volumes-from/image volumes with unified volumes from above.
+	// This is an unconditional replacement.
+	for dest, mount := range unifiedMounts {
+		baseMounts[dest] = mount
+	}
+	for dest, volume := range unifiedVolumes {
+		baseVolumes[dest] = volume
+	}
+
+	// TODO: Investigate moving readonlyTmpfs into here. Would be more
+	// correct.
+
+	// Check for conflicts between named volumes and mounts
+	for dest := range baseMounts {
+		if _, ok := baseVolumes[dest]; ok {
+			return nil, nil, errors.Wrapf(errDuplicateDest, "conflict at mount destination %v", dest)
+		}
+	}
+	for dest := range baseVolumes {
+		if _, ok := baseMounts[dest]; ok {
+			return nil, nil, errors.Wrapf(errDuplicateDest, "conflict at mount destination %v", dest)
+		}
+	}
+	// Final step: maps to arrays
+	finalMounts := make([]spec.Mount, 0, len(baseMounts))
+	for _, mount := range baseMounts {
+		if mount.Type == TypeBind {
+			absSrc, err := filepath.Abs(mount.Source)
+			if err != nil {
+				return nil, nil, errors.Wrapf(err, "error getting absolute path of %s", mount.Source)
+			}
+			mount.Source = absSrc
+		}
+		finalMounts = append(finalMounts, mount)
+	}
+	finalVolumes := make([]*specgen.NamedVolume, 0, len(baseVolumes))
+	for _, volume := range baseVolumes {
+		finalVolumes = append(finalVolumes, volume)
+	}
+
+	return finalMounts, finalVolumes, nil
+}
+
+// Get image volumes from the given image
+func getImageVolumes(ctx context.Context, img *image.Image, s *specgen.SpecGenerator) (map[string]spec.Mount, map[string]*specgen.NamedVolume, error) {
+	mounts := make(map[string]spec.Mount)
+	volumes := make(map[string]*specgen.NamedVolume)
+
+	mode := strings.ToLower(s.ImageVolumeMode)
+
+	// Image may be nil (rootfs in use), or image volume mode may be ignore.
+	if img == nil || mode == "ignore" {
+		return mounts, volumes, nil
+	}
+
+	inspect, err := img.InspectNoSize(ctx)
+	if err != nil {
+		return nil, nil, errors.Wrapf(err, "error inspecting image to get image volumes")
+	}
+	for volume := range inspect.Config.Volumes {
+		logrus.Debugf("Image has volume at %q", volume)
+		cleanDest := filepath.Clean(volume)
+		switch mode {
+		case "", "anonymous":
+			// Anonymous volumes have no name.
+			newVol := new(specgen.NamedVolume)
+			newVol.Dest = cleanDest
+			newVol.Options = []string{"rprivate", "rw", "nodev", "exec"}
+			volumes[cleanDest] = newVol
+			logrus.Debugf("Adding anonymous image volume at %q", cleanDest)
+		case "tmpfs":
+			mount := spec.Mount{
+				Destination: cleanDest,
+				Source:      TypeTmpfs,
+				Type:        TypeTmpfs,
+				Options:     []string{"rprivate", "rw", "nodev", "exec"},
+			}
+			mounts[cleanDest] = mount
+			logrus.Debugf("Adding tmpfs image volume at %q", cleanDest)
+		}
+	}
+
+	return mounts, volumes, nil
+}
+
+func getVolumesFrom(volumesFrom []string, runtime *libpod.Runtime) (map[string]spec.Mount, map[string]*specgen.NamedVolume, error) {
+	finalMounts := make(map[string]spec.Mount)
+	finalNamedVolumes := make(map[string]*specgen.NamedVolume)
+
+	for _, volume := range volumesFrom {
+		var options []string
+
+		splitVol := strings.SplitN(volume, ":", 2)
+		if len(splitVol) == 2 {
+			splitOpts := strings.Split(splitVol[1], ",")
+			for _, opt := range splitOpts {
+				setRORW := false
+				setZ := false
+				switch opt {
+				case "z":
+					if setZ {
+						return nil, nil, errors.Errorf("cannot set :z more than once in mount options")
+					}
+					setZ = true
+				case "ro", "rw":
+					if setRORW {
+						return nil, nil, errors.Errorf("cannot set ro or rw options more than once")
+					}
+					setRORW = true
+				default:
+					return nil, nil, errors.Errorf("invalid option %q specified - volumes from another container can only use z,ro,rw options", opt)
+				}
+			}
+			options = splitOpts
+		}
+
+		ctr, err := runtime.LookupContainer(splitVol[0])
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "error looking up container %q for volumes-from", splitVol[0])
+		}
+
+		logrus.Debugf("Adding volumes from container %s", ctr.ID())
+
+		// Look up the container's user volumes. This gets us the
+		// destinations of all mounts the user added to the container.
+		userVolumesArr := ctr.UserVolumes()
+
+		// We're going to need to access them a lot, so convert to a map
+		// to reduce looping.
+		// We'll also use the map to indicate if we missed any volumes along the way.
+		userVolumes := make(map[string]bool)
+		for _, dest := range userVolumesArr {
+			userVolumes[dest] = false
+		}
+
+		// Now we get the container's spec and loop through its volumes
+		// and append them in if we can find them.
+		spec := ctr.Spec()
+		if spec == nil {
+			return nil, nil, errors.Errorf("error retrieving container %s spec for volumes-from", ctr.ID())
+		}
+		for _, mnt := range spec.Mounts {
+			if mnt.Type != TypeBind {
+				continue
+			}
+			if _, exists := userVolumes[mnt.Destination]; exists {
+				userVolumes[mnt.Destination] = true
+
+				if len(options) != 0 {
+					mnt.Options = options
+				}
+
+				if _, ok := finalMounts[mnt.Destination]; ok {
+					logrus.Debugf("Overriding mount to %s with new mount from container %s", mnt.Destination, ctr.ID())
+				}
+				finalMounts[mnt.Destination] = mnt
+			}
+		}
+
+		// We're done with the spec mounts. Add named volumes.
+		// Add these unconditionally - none of them are automatically
+		// part of the container, as some spec mounts are.
+		namedVolumes := ctr.NamedVolumes()
+		for _, namedVol := range namedVolumes {
+			if _, exists := userVolumes[namedVol.Dest]; exists {
+				userVolumes[namedVol.Dest] = true
+			}
+
+			if len(options) != 0 {
+				namedVol.Options = options
+			}
+
+			if _, ok := finalMounts[namedVol.Dest]; ok {
+				logrus.Debugf("Overriding named volume mount to %s with new named volume from container %s", namedVol.Dest, ctr.ID())
+			}
+
+			newVol := new(specgen.NamedVolume)
+			newVol.Dest = namedVol.Dest
+			newVol.Options = namedVol.Options
+			newVol.Name = namedVol.Name
+
+			finalNamedVolumes[namedVol.Dest] = newVol
+		}
+
+		// Check if we missed any volumes
+		for volDest, found := range userVolumes {
+			if !found {
+				logrus.Warnf("Unable to match volume %s from container %s for volumes-from", volDest, ctr.ID())
+			}
+		}
+	}
+
+	return finalMounts, finalNamedVolumes, nil
+}
+
+// AddContainerInitBinary adds the init binary specified by path iff the
+// container will run in a private PID namespace that is not shared with the
+// host or another pre-existing container, where an init-like process is
+// already running.
+// This does *NOT* modify the container command - that must be done elsewhere.
+func addContainerInitBinary(s *specgen.SpecGenerator, path string) (spec.Mount, error) {
+	mount := spec.Mount{
+		Destination: "/dev/init",
+		Type:        TypeBind,
+		Source:      path,
+		Options:     []string{TypeBind, "ro"},
+	}
+
+	if path == "" {
+		return mount, fmt.Errorf("please specify a path to the container-init binary")
+	}
+	if !s.PidNS.IsPrivate() {
+		return mount, fmt.Errorf("cannot add init binary as PID 1 (PID namespace isn't private)")
+	}
+	if s.Systemd == "true" || s.Systemd == "always" {
+		return mount, fmt.Errorf("cannot use container-init binary with systemd")
+	}
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		return mount, errors.Wrap(err, "container-init binary not found on the host")
+	}
+	return mount, nil
+}
+
 // Supersede existing mounts in the spec with new, user-specified mounts.
 // TODO: Should we unmount subtree mounts? E.g., if /tmp/ is mounted by
 // one mount, and we already have /tmp/a and /tmp/b, should we remove