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// Copyright (c) Contributors to the Apptainer project, established as
// Apptainer a Series of LF Projects LLC.
// For website terms of use, trademark policy, privacy policy and other
// project policies see https://lfprojects.org/policies
// Copyright (c) 2019-2020, Sylabs Inc. All rights reserved.
// This software is licensed under a 3-clause BSD license. Please consult the
// LICENSE.md file distributed with the sources of this project regarding your
// rights to use or distribute this software.
package sifbundle
import (
"encoding/json"
"fmt"
"os"
"path/filepath"
"strings"
"syscall"
"github.com/apptainer/apptainer/internal/pkg/runtime/engine/config/oci/generate"
imageSpecs "github.com/opencontainers/image-spec/specs-go/v1"
specs "github.com/opencontainers/runtime-spec/specs-go"
"github.com/apptainer/apptainer/pkg/image"
"github.com/apptainer/apptainer/pkg/ocibundle"
"github.com/apptainer/apptainer/pkg/ocibundle/tools"
)
type sifBundle struct {
image string
bundlePath string
writable bool
ocibundle.Bundle
}
func (s *sifBundle) writeConfig(img *image.Image, g *generate.Generator) error {
// check if SIF file contain an OCI image configuration
reader, err := image.NewSectionReader(img, image.SIFDescOCIConfigJSON, -1)
if err != nil && err != image.ErrNoSection {
return fmt.Errorf("failed to read %s section: %s", image.SIFDescOCIConfigJSON, err)
} else if err == image.ErrNoSection {
return tools.SaveBundleConfig(s.bundlePath, g)
}
var imgConfig imageSpecs.ImageConfig
if err := json.NewDecoder(reader).Decode(&imgConfig); err != nil {
return fmt.Errorf("failed to decode %s: %s", image.SIFDescOCIConfigJSON, err)
}
if len(g.Config.Process.Args) == 1 && g.Config.Process.Args[0] == tools.RunScript {
args := imgConfig.Entrypoint
args = append(args, imgConfig.Cmd...)
if len(args) > 0 {
g.SetProcessArgs(args)
}
}
if g.Config.Process.Cwd == "" && imgConfig.WorkingDir != "" {
g.SetProcessCwd(imgConfig.WorkingDir)
}
for _, e := range imgConfig.Env {
found := false
k := strings.SplitN(e, "=", 2)
for _, pe := range g.Config.Process.Env {
if strings.HasPrefix(pe, k[0]+"=") {
found = true
break
}
}
if !found {
g.SetProcessEnv(k[0], k[1])
}
}
volumes := tools.Volumes(s.bundlePath).Path()
for dst := range imgConfig.Volumes {
replacer := strings.NewReplacer(string(os.PathSeparator), "_")
src := filepath.Join(volumes, replacer.Replace(dst))
if err := os.MkdirAll(src, 0o755); err != nil {
return fmt.Errorf("failed to create volume directory %s: %s", src, err)
}
g.AddMount(specs.Mount{
Source: src,
Destination: dst,
Type: "none",
Options: []string{"bind", "rw"},
})
}
return tools.SaveBundleConfig(s.bundlePath, g)
}
// Create creates an OCI bundle from a SIF image
func (s *sifBundle) Create(ociConfig *specs.Spec) error {
if s.image == "" {
return fmt.Errorf("image wasn't set, need one to create bundle")
}
img, err := image.Init(s.image, s.writable)
if err != nil {
return fmt.Errorf("failed to load SIF image %s: %s", s.image, err)
}
defer img.File.Close()
if img.Type != image.SIF {
return fmt.Errorf("%s is not a SIF image", s.image)
}
part, err := img.GetRootFsPartition()
if err != nil {
return fmt.Errorf("while getting root filesystem in SIF %s: %s", s.image, err)
}
if part.Type != image.SQUASHFS {
return fmt.Errorf("unsupported image fs type: %v", part.Type)
}
offset := part.Offset
size := part.Size
// generate OCI bundle directory and config
g, err := tools.GenerateBundleConfig(s.bundlePath, ociConfig)
if err != nil {
return fmt.Errorf("failed to generate OCI bundle/config: %s", err)
}
// associate SIF image with a block
loop, loopCloser, err := tools.CreateLoop(img.File, offset, size)
if err != nil {
tools.DeleteBundle(s.bundlePath)
return fmt.Errorf("failed to find loop device: %s", err)
}
defer loopCloser.Close()
rootFs := tools.RootFs(s.bundlePath).Path()
if err := syscall.Mount(loop, rootFs, "squashfs", syscall.MS_RDONLY, ""); err != nil {
tools.DeleteBundle(s.bundlePath)
return fmt.Errorf("failed to mount SIF partition: %s", err)
}
if err := s.writeConfig(img, g); err != nil {
// best effort to release loop device
syscall.Unmount(rootFs, syscall.MNT_DETACH)
tools.DeleteBundle(s.bundlePath)
return fmt.Errorf("failed to write OCI configuration: %s", err)
}
if s.writable {
if err := tools.CreateOverlay(s.bundlePath); err != nil {
// best effort to release loop device
syscall.Unmount(rootFs, syscall.MNT_DETACH)
tools.DeleteBundle(s.bundlePath)
return fmt.Errorf("failed to create overlay: %s", err)
}
}
return nil
}
// Delete erases OCI bundle create from SIF image
func (s *sifBundle) Delete() error {
if s.writable {
if err := tools.DeleteOverlay(s.bundlePath); err != nil {
return fmt.Errorf("delete error: %s", err)
}
}
// Umount rootfs
rootFsDir := tools.RootFs(s.bundlePath).Path()
if err := syscall.Unmount(rootFsDir, syscall.MNT_DETACH); err != nil {
return fmt.Errorf("failed to unmount %s: %s", rootFsDir, err)
}
// delete bundle directory
return tools.DeleteBundle(s.bundlePath)
}
// FromSif returns a bundle interface to create/delete OCI bundle from SIF image
func FromSif(image, bundle string, writable bool) (ocibundle.Bundle, error) {
var err error
s := &sifBundle{
writable: writable,
}
s.bundlePath, err = filepath.Abs(bundle)
if err != nil {
return nil, fmt.Errorf("failed to determine bundle path: %s", err)
}
if image != "" {
s.image, err = filepath.Abs(image)
if err != nil {
return nil, fmt.Errorf("failed to determine image path: %s", err)
}
}
return s, nil
}
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