containerd/mount.go
Michael Crosby a7a6270f2a Remove shelling out to mount
Also remove the target from the Mount struct because it should not be
used at all.  The target can be variable and set by a caller, not by the
snapshot drivers.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
2017-01-18 11:10:31 -08:00

88 lines
2.7 KiB
Go

package containerd
import (
"strings"
"syscall"
)
// Mount is the lingua franca of containerd. A mount represents a
// serialized mount syscall. Components either emit or consume mounts.
type Mount struct {
// Type specifies the host-specific of the mount.
Type string
// Source specifies where to mount from. Depending on the host system, this
// can be a source path or device.
Source string
// Options contains zero or more fstab-style mount options. Typically,
// these are platform specific.
Options []string
}
func (m *Mount) Mount(target string) error {
flags, data := parseMountOptions(m.Options)
return syscall.Mount(m.Source, target, m.Type, uintptr(flags), data)
}
// MountAll mounts all the provided mounts to the provided target
func MountAll(mounts []Mount, target string) error {
for _, m := range mounts {
if err := m.Mount(target); err != nil {
return err
}
}
return nil
}
// parseMountOptions takes fstab style mount options and parses them for
// use with a standard mount() syscall
func parseMountOptions(options []string) (int, string) {
var (
flag int
data []string
)
flags := map[string]struct {
clear bool
flag int
}{
"async": {true, syscall.MS_SYNCHRONOUS},
"atime": {true, syscall.MS_NOATIME},
"bind": {false, syscall.MS_BIND},
"defaults": {false, 0},
"dev": {true, syscall.MS_NODEV},
"diratime": {true, syscall.MS_NODIRATIME},
"dirsync": {false, syscall.MS_DIRSYNC},
"exec": {true, syscall.MS_NOEXEC},
"mand": {false, syscall.MS_MANDLOCK},
"noatime": {false, syscall.MS_NOATIME},
"nodev": {false, syscall.MS_NODEV},
"nodiratime": {false, syscall.MS_NODIRATIME},
"noexec": {false, syscall.MS_NOEXEC},
"nomand": {true, syscall.MS_MANDLOCK},
"norelatime": {true, syscall.MS_RELATIME},
"nostrictatime": {true, syscall.MS_STRICTATIME},
"nosuid": {false, syscall.MS_NOSUID},
"rbind": {false, syscall.MS_BIND | syscall.MS_REC},
"relatime": {false, syscall.MS_RELATIME},
"remount": {false, syscall.MS_REMOUNT},
"ro": {false, syscall.MS_RDONLY},
"rw": {true, syscall.MS_RDONLY},
"strictatime": {false, syscall.MS_STRICTATIME},
"suid": {true, syscall.MS_NOSUID},
"sync": {false, syscall.MS_SYNCHRONOUS},
}
for _, o := range options {
// If the option does not exist in the flags table or the flag
// is not supported on the platform,
// then it is a data value for a specific fs type
if f, exists := flags[o]; exists && f.flag != 0 {
if f.clear {
flag &= ^f.flag
} else {
flag |= f.flag
}
} else {
data = append(data, o)
}
}
return flag, strings.Join(data, ",")
}