buildkit/executor/oci/mounts.go

118 lines
2.9 KiB
Go

package oci
import (
"context"
"path/filepath"
"strings"
specs "github.com/opencontainers/runtime-spec/specs-go"
"github.com/pkg/errors"
)
// MountOpts sets oci spec specific info for mount points
type MountOpts func([]specs.Mount) ([]specs.Mount, error)
//GetMounts returns default required for buildkit
// https://github.com/moby/buildkit/issues/429
func GetMounts(ctx context.Context, mountOpts ...MountOpts) ([]specs.Mount, error) {
mounts := []specs.Mount{
{
Destination: "/proc",
Type: "proc",
Source: "proc",
},
{
Destination: "/dev",
Type: "tmpfs",
Source: "tmpfs",
Options: []string{"nosuid", "strictatime", "mode=755", "size=65536k"},
},
{
Destination: "/dev/pts",
Type: "devpts",
Source: "devpts",
Options: []string{"nosuid", "noexec", "newinstance", "ptmxmode=0666", "mode=0620", "gid=5"},
},
{
Destination: "/dev/shm",
Type: "tmpfs",
Source: "shm",
Options: []string{"nosuid", "noexec", "nodev", "mode=1777", "size=65536k"},
},
{
Destination: "/dev/mqueue",
Type: "mqueue",
Source: "mqueue",
Options: []string{"nosuid", "noexec", "nodev"},
},
{
Destination: "/sys",
Type: "sysfs",
Source: "sysfs",
Options: []string{"nosuid", "noexec", "nodev", "ro"},
},
}
var err error
for _, o := range mountOpts {
mounts, err = o(mounts)
if err != nil {
return nil, err
}
}
return mounts, nil
}
func withROBind(src, dest string) func(m []specs.Mount) ([]specs.Mount, error) {
return func(m []specs.Mount) ([]specs.Mount, error) {
m = append(m, specs.Mount{
Destination: dest,
Type: "bind",
Source: src,
Options: []string{"rbind", "ro"},
})
return m, nil
}
}
func hasPrefix(p, prefixDir string) bool {
prefixDir = filepath.Clean(prefixDir)
if prefixDir == "/" {
return true
}
p = filepath.Clean(p)
return p == prefixDir || strings.HasPrefix(p, prefixDir+"/")
}
func removeMountsWithPrefix(mounts []specs.Mount, prefixDir string) []specs.Mount {
var ret []specs.Mount
for _, m := range mounts {
if !hasPrefix(m.Destination, prefixDir) {
ret = append(ret, m)
}
}
return ret
}
func withProcessMode(processMode ProcessMode) func([]specs.Mount) ([]specs.Mount, error) {
return func(m []specs.Mount) ([]specs.Mount, error) {
switch processMode {
case ProcessSandbox:
// keep the default
case NoProcessSandbox:
m = removeMountsWithPrefix(m, "/proc")
procMount := specs.Mount{
Destination: "/proc",
Type: "bind",
Source: "/proc",
// NOTE: "rbind"+"ro" does not make /proc read-only recursively.
// So we keep maskedPath and readonlyPaths (although not mandatory for rootless mode)
Options: []string{"rbind"},
}
m = append([]specs.Mount{procMount}, m...)
default:
return nil, errors.Errorf("unknown process mode: %v", processMode)
}
return m, nil
}
}