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a7a6270 Jan 18, 2017
@stevvooe @crosbymichael @cpuguy83
89 lines (83 sloc) 2.71 KB
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, ",")
}