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Merge pull request #529 from jiangliu/overlayfs
cmd: move nydus-overlayfs from image service to snapshotter
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,146 @@ | ||
package main | ||
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import ( | ||
"fmt" | ||
"log" | ||
"os" | ||
"strings" | ||
"syscall" | ||
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"github.com/pkg/errors" | ||
"github.com/urfave/cli/v2" | ||
"golang.org/x/sys/unix" | ||
) | ||
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const ( | ||
// Extra mount option to pass Nydus specific information from snapshotter to runtime through containerd. | ||
extraOptionKey = "extraoption=" | ||
// Kata virtual volume infmation passed from snapshotter to runtime through containerd, superset of `extraOptionKey`. | ||
// Please refer to `KataVirtualVolume` in https://github.com/kata-containers/kata-containers/blob/main/src/libs/kata-types/src/mount.rs | ||
kataVolumeOptionKey = "io.katacontainers.volume=" | ||
) | ||
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var ( | ||
Version = "v0.1" | ||
BuildTime = "unknown" | ||
) | ||
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/* | ||
containerd run fuse.mount format: nydus-overlayfs overlay /tmp/ctd-volume107067851 | ||
-o lowerdir=/foo/lower2:/foo/lower1,upperdir=/foo/upper,workdir=/foo/work,extraoption={...},dev,suid] | ||
*/ | ||
type mountArgs struct { | ||
fsType string | ||
target string | ||
options []string | ||
} | ||
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func parseArgs(args []string) (*mountArgs, error) { | ||
margs := &mountArgs{ | ||
fsType: args[0], | ||
target: args[1], | ||
} | ||
if margs.fsType != "overlay" { | ||
return nil, errors.Errorf("invalid filesystem type %s for overlayfs", margs.fsType) | ||
} | ||
if len(margs.target) == 0 { | ||
return nil, errors.New("empty overlayfs mount target") | ||
} | ||
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if args[2] == "-o" && len(args[3]) != 0 { | ||
for _, opt := range strings.Split(args[3], ",") { | ||
// filter Nydus specific options | ||
if strings.HasPrefix(opt, extraOptionKey) || strings.HasPrefix(opt, kataVolumeOptionKey) { | ||
continue | ||
} | ||
margs.options = append(margs.options, opt) | ||
} | ||
} | ||
if len(margs.options) == 0 { | ||
return nil, errors.New("empty overlayfs mount options") | ||
} | ||
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return margs, nil | ||
} | ||
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func parseOptions(options []string) (int, string) { | ||
flagsTable := map[string]int{ | ||
"async": unix.MS_SYNCHRONOUS, | ||
"atime": unix.MS_NOATIME, | ||
"bind": unix.MS_BIND, | ||
"defaults": 0, | ||
"dev": unix.MS_NODEV, | ||
"diratime": unix.MS_NODIRATIME, | ||
"dirsync": unix.MS_DIRSYNC, | ||
"exec": unix.MS_NOEXEC, | ||
"mand": unix.MS_MANDLOCK, | ||
"noatime": unix.MS_NOATIME, | ||
"nodev": unix.MS_NODEV, | ||
"nodiratime": unix.MS_NODIRATIME, | ||
"noexec": unix.MS_NOEXEC, | ||
"nomand": unix.MS_MANDLOCK, | ||
"norelatime": unix.MS_RELATIME, | ||
"nostrictatime": unix.MS_STRICTATIME, | ||
"nosuid": unix.MS_NOSUID, | ||
"rbind": unix.MS_BIND | unix.MS_REC, | ||
"relatime": unix.MS_RELATIME, | ||
"remount": unix.MS_REMOUNT, | ||
"ro": unix.MS_RDONLY, | ||
"rw": unix.MS_RDONLY, | ||
"strictatime": unix.MS_STRICTATIME, | ||
"suid": unix.MS_NOSUID, | ||
"sync": unix.MS_SYNCHRONOUS, | ||
} | ||
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var ( | ||
flags int | ||
data []string | ||
) | ||
for _, o := range options { | ||
if f, exist := flagsTable[o]; exist { | ||
flags |= f | ||
} else { | ||
data = append(data, o) | ||
} | ||
} | ||
return flags, strings.Join(data, ",") | ||
} | ||
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func run(args cli.Args) error { | ||
margs, err := parseArgs(args.Slice()) | ||
if err != nil { | ||
return errors.Wrap(err, "parse mount options") | ||
} | ||
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flags, data := parseOptions(margs.options) | ||
err = syscall.Mount(margs.fsType, margs.target, margs.fsType, uintptr(flags), data) | ||
if err != nil { | ||
return errors.Wrapf(err, "mount overlayfs by syscall") | ||
} | ||
return nil | ||
} | ||
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func main() { | ||
app := &cli.App{ | ||
Name: "NydusOverlayfs", | ||
Usage: "FUSE mount helper for containerd to filter out Nydus specific options", | ||
Version: fmt.Sprintf("%s.%s", Version, BuildTime), | ||
UsageText: "[Usage]: nydus-overlayfs overlay <target> -o <options>", | ||
Action: func(c *cli.Context) error { | ||
return run(c.Args()) | ||
}, | ||
Before: func(c *cli.Context) error { | ||
if c.NArg() != 4 { | ||
cli.ShowAppHelpAndExit(c, 1) | ||
} | ||
return nil | ||
}, | ||
} | ||
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err := app.Run(os.Args) | ||
if err != nil { | ||
log.Fatal(err) | ||
} | ||
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os.Exit(0) | ||
} |