system/fs.go
package system
import (
"fmt"
"io/ioutil"
"os/exec"
"reflect"
"regexp"
"strconv"
"strings"
"syscall"
)
var mountOptionSeparator = regexp.MustCompile("[[:space:]]*,[[:space:]]*")
// IsXFSOption matches xfs options
var IsXFSOption = regexp.MustCompile(`^xfsopt_\w+$`)
var fstab = "/etc/fstab"
var mtab = "/etc/mtab"
var procMounts = "/proc/mounts"
// MountPoint Represent a mount point entry in /proc/mounts or /etc/fstab
type MountPoint struct {
Device string
MountPoint string
Type string
Options []string
Dump int
Fsck int
}
// Equals return true only if two mount points are identical in all attributes.
func (mount1 MountPoint) Equals(mount2 MountPoint) bool {
return reflect.DeepEqual(mount1, mount2)
}
// GetFileSystemSizeMB return the total size of the file system in MegaBytes.
// Panic on error.
func (mount MountPoint) GetFileSystemSizeMB() uint64 {
fs := syscall.Statfs_t{}
err := syscall.Statfs(mount.MountPoint, &fs)
if err != nil {
panic(fmt.Errorf("failed to stat file system on mount point %s - %v", mount.MountPoint, err))
}
return uint64(fs.Bsize) * fs.Blocks / 1048576
}
// MountPoints contains a list of mount points.
type MountPoints []MountPoint
// GetByMountPoint find a mount point by its path.
func (mounts MountPoints) GetByMountPoint(mountPoint string) (MountPoint, bool) {
for _, mount := range mounts {
if mount.MountPoint == mountPoint {
return mount, true
}
}
return MountPoint{}, false
}
// GetByMountOption find a mount point with special mount option.
// returns a list of mount points containing the option and a second list
// with mount points missing the option.
func (mounts MountPoints) GetByMountOption(fstype, mountOption, chkDflt string) ([]string, []string) {
var found bool
var dflt bool
mntOK := []string{}
mntNok := []string{}
for _, mount := range mounts {
if mount.Type == fstype {
found = false
dflt = false
for _, opt := range mount.Options {
if opt == mountOption {
found = true
mntOK = append(mntOK, mount.MountPoint)
break
}
if opt == "defaults" {
dflt = true
}
}
if !found {
if dflt && chkDflt == "chkOK" {
mntOK = append(mntOK, mount.MountPoint)
} else {
mntNok = append(mntNok, mount.MountPoint)
}
}
}
}
return mntOK, mntNok
}
// ParseMounts return all mount points defined in the input text.
// Skipping malformed entry.
func ParseMounts(txt string) (mounts MountPoints) {
mounts = make([]MountPoint, 0)
for _, line := range strings.Split(txt, "\n") {
fields := consecutiveSpaces.Split(strings.TrimSpace(line), -1)
if len(fields) == 0 || len(fields[0]) == 0 || fields[0][0] == '#' {
continue // skip comments and empty lines
}
if len(fields) < 4 {
// skip lines with wrong syntax
ErrorLog("parsing mounts - incorrect number of fields in line '%s'. Skipping entry", line)
continue
}
mountPoint := MountPoint{
Device: fields[0],
MountPoint: fields[1],
Type: fields[2],
Dump: 0,
Fsck: 0,
}
// Split mount options
mountPoint.Options = mountOptionSeparator.Split(fields[3], -1)
var err error
if len(fields) > 4 {
if mountPoint.Dump, err = strconv.Atoi(fields[4]); err != nil {
WarningLog("parsing mounts - not an integer for field 'dump' in '%s'. Working with default value '0'.", line)
}
}
if len(fields) > 5 {
if mountPoint.Fsck, err = strconv.Atoi(fields[5]); err != nil {
WarningLog("parsing mounts - not an integer for field 'fsck' in '%s'. Working with default value '0'.", line)
}
}
mounts = append(mounts, mountPoint)
}
return
}
// ParseMtab return all mount points defined in a given file.
// Returns empty list of mount points on error
func ParseMtab(file string) MountPoints {
mounts := ""
content, err := ioutil.ReadFile(file)
if err != nil {
ErrorLog("failed to read file '%s': %v", file, err)
} else {
mounts = string(content)
}
return ParseMounts(mounts)
}
// ParseFstab return all mount points defined in /etc/fstab.
// Returns empty list of mount points
func ParseFstab() MountPoints {
return ParseMtab(fstab)
}
// ParseProcMounts return all mount points appearing in /proc/mounts.
// Returns empty list of mount points
func ParseProcMounts() MountPoints {
return ParseMtab(procMounts)
}
// ParseMtabMounts return all mount points appearing in /etc/mtab.
// Returns empty list of mount points
func ParseMtabMounts() MountPoints {
return ParseMtab(mtab)
}
// RemountSHM invoke mount command to resize /dev/shm to the specified value.
func RemountSHM(newSizeMB uint64) error {
cmd := exec.Command("mount", "-o", fmt.Sprintf("remount,size=%dM", newSizeMB), "/dev/shm")
if out, err := cmd.CombinedOutput(); err != nil {
return fmt.Errorf("failed to invoke external command mount: %v, output: %s", err, out)
}
return nil
}
// GetMountOpts checks if mount points with the given type exists and contain
// the needed/not needed option.
// Returns a list of mount point containing the option and a list of mount
// point NOT containing the option
func GetMountOpts(mustExist bool, fstype, fsopt string) ([]string, []string) {
// Find out mount options
chkdflt := "noChk"
// check the mounted FS
mountProcOk, mountProcNok := ParseProcMounts().GetByMountOption(fstype, fsopt, chkdflt)
if mustExist {
chkdflt = "chkOK"
} else {
chkdflt = "chkNOK"
}
// check /etc/fstab to get the not mounted FS as well
mountFSTOk, mountFSTNok := ParseFstab().GetByMountOption(fstype, fsopt, chkdflt)
mntOk := getMounts(mountProcOk, mountFSTOk)
mntNok := getMounts(mountProcNok, mountFSTNok)
return mntOk, mntNok
}
// getMounts combines the mounted and not mounted FS
func getMounts(neededProcMnts, mntsFromFstab []string) []string {
// initialize with the mounted FS
mntRet := neededProcMnts
for _, mnt := range mntsFromFstab {
// search for not mounted FS, which are NOK/OK
// and append them to the needed mounts
found := isMntAvail(mnt, neededProcMnts)
if !found {
mntRet = append(mntRet, mnt)
}
}
return mntRet
}
// isMntAvail checks, if a given mount point is available in a pool of
// mount points.
// returns true, if the mount point exists in the pool, otherwise false
func isMntAvail(mntPt string, poolOfMnts []string) bool {
ret := false
for _, mnt := range poolOfMnts {
if mntPt == mnt {
ret = true
break
}
}
return ret
}