format: Add partition labels and new filesystems

This commit re-writes the format package in Go and adds the ability to
add partition labels and also specify either ext4, btrfs or xfs

Signed-off-by: Dave Tucker <dt@docker.com>

pkg/format/Dockerfile

@@ -1,4 +1,4 @@
-FROM linuxkit/alpine:9bcf61f605ef0ce36cc94d59b8eac307862de6e1 AS mirror
+FROM linuxkit/alpine:488aa6f5dd2d8121a3c5c5c7a1ecf97c424b96ac AS mirror
 
 RUN mkdir -p /out/etc/apk && cp -r /etc/apk/* /out/etc/apk/
 RUN apk add --no-cache --initdb -p /out \
@@ -6,17 +6,27 @@ RUN apk add --no-cache --initdb -p /out \
     busybox \
     e2fsprogs \
     e2fsprogs-extra \
-    jq \
+    btrfs-progs \
+    xfsprogs \
     musl \
     sfdisk \
+    util-linux \
     && true
 RUN rm -rf /out/etc/apk /out/lib/apk /out/var/cache
 
+FROM linuxkit/alpine:488aa6f5dd2d8121a3c5c5c7a1ecf97c424b96ac AS build
+
+RUN apk add --no-cache go musl-dev
+ENV GOPATH=/go PATH=$PATH:/go/bin
+
+COPY format.go /go/src/format/
+RUN go-compile.sh /go/src/format
+
 FROM scratch
 ENTRYPOINT []
 CMD []
 WORKDIR /
 COPY --from=mirror /out/ /
-COPY format.sh /
+COPY --from=build /go/bin/format usr/bin/format
-CMD ["/bin/sh", "/format.sh"]
+CMD ["/usr/bin/format"]
 LABEL org.mobyproject.config='{"binds": ["/dev:/dev"], "capabilities": ["CAP_SYS_ADMIN", "CAP_MKNOD"], "net": "new", "ipc": "new"}'

pkg/format/Makefile

@@ -1,4 +1,4 @@
 IMAGE=format
-DEPS=format.sh
+DEPS=format.go
 
 include ../package.mk

pkg/format/format.go

@@ -0,0 +1,184 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strings"
+	"syscall"
+	"time"
+)
+
+const (
+	timeout  = 60
+	ext4opts = "resize_inode,has_journal,extent,huge_file,flex_bg,uninit_bg,64bit,dir_nlink,extra_isize"
+)
+
+var (
+	labelVar  string
+	fsTypeVar string
+	drives    map[string]bool
+	driveKeys []string
+)
+
+func autoformat(label, fsType string) error {
+	var first string
+	for _, d := range driveKeys {
+		err := exec.Command("sfdisk", "-d", d).Run()
+		if err == nil {
+			log.Printf("Partition table found on device %s. Skipping.", d)
+			continue
+		}
+		first = d
+		break
+	}
+
+	if first == "" {
+		return fmt.Errorf("No eligible disks found")
+	}
+
+	if err := format(first, label, fsType); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func format(d, label, fsType string) error {
+	log.Printf("Creating partition on %s", d)
+	/* new disks do not have an DOS signature in sector 0
+	this makes sfdisk complain. We can workaround this by letting
+	fdisk create that DOS signature, by just do a "w", a write.
+	http://bugs.alpinelinux.org/issues/145
+	*/
+	fdiskCmd := exec.Command("fdisk", d)
+	fdiskCmd.Stdin = strings.NewReader("w")
+	if out, err := fdiskCmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("Error running fdisk: %v\n%s", err, out)
+	}
+
+	// format one large partition
+	partCmd := exec.Command("sfdisk", "--quiet", d)
+	partCmd.Stdin = strings.NewReader(";")
+	if out, err := partCmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("Error running sfdisk: %v\n%s", err, out)
+	}
+
+	// update status
+	if err := exec.Command("blockdev", "--rereadpt", d).Run(); err != nil {
+		return fmt.Errorf("Error running blockdev: %v", err)
+	}
+
+	exec.Command("mdev", "-s").Run()
+
+	partition := fmt.Sprintf("%s1", d)
+	// wait for device
+	var done bool
+	for i := 0; i < timeout; i++ {
+		stat, err := os.Stat(partition)
+		if err == nil {
+			mode := stat.Sys().(*syscall.Stat_t).Mode
+			if (mode & syscall.S_IFMT) == syscall.S_IFBLK {
+				done = true
+				break
+			}
+		}
+		time.Sleep(100 * time.Millisecond)
+		exec.Command("mdev", "-s").Run()
+	}
+	if !done {
+		return fmt.Errorf("Error waiting for device %s", partition)
+	}
+	// even after the device appears we still have a race
+	time.Sleep(1 * time.Second)
+
+	// mkfs
+	mkfsArgs := []string{"-t", fsType}
+
+	switch fsType {
+	case "ext4":
+		ext4Args := []string{"-F", "-O", ext4opts}
+		if label != "" {
+			ext4Args = append(ext4Args, []string{"-L", label}...)
+		}
+		mkfsArgs = append(mkfsArgs, ext4Args...)
+	case "btrfs":
+		btrfsArgs := []string{"-f"}
+		if label != "" {
+			btrfsArgs = append(btrfsArgs, []string{"-l", label}...)
+		}
+		mkfsArgs = append(mkfsArgs, btrfsArgs...)
+	case "xfs":
+		xfsArgs := []string{"-f"}
+		if label != "" {
+			xfsArgs = append(xfsArgs, []string{"-L", label}...)
+		}
+		mkfsArgs = append(mkfsArgs, xfsArgs...)
+	default:
+		log.Println("WARNING: Unsupported filesystem.")
+	}
+
+	mkfsArgs = append(mkfsArgs, partition)
+	if out, err := exec.Command("mkfs", mkfsArgs...).CombinedOutput(); err != nil {
+		return fmt.Errorf("Error running mkfs: %v\n%s", err, string(out))
+	}
+
+	log.Printf("Partition %s successfully created!", partition)
+	return nil
+}
+
+// return a list of all available drives
+func findDrives() {
+	drives = make(map[string]bool)
+	driveKeys = []string{}
+	ignoreExp := regexp.MustCompile(`^loop.*$|^nbd.*$|^[a-z]+[0-9]+$`)
+	devs, _ := ioutil.ReadDir("/dev")
+	for _, d := range devs {
+		// this probably shouldn't be so hard
+		// but d.Mode()&os.ModeDevice == 0 doesn't work as expected
+		mode := d.Sys().(*syscall.Stat_t).Mode
+		if (mode & syscall.S_IFMT) != syscall.S_IFBLK {
+			continue
+		}
+		// ignore if it matches regexp
+		if ignoreExp.MatchString(d.Name()) {
+			continue
+		}
+		driveKeys = append(driveKeys, filepath.Join("/dev", d.Name()))
+	}
+	sort.Strings(driveKeys)
+	for _, d := range driveKeys {
+		drives[d] = true
+	}
+}
+
+func init() {
+	flag.StringVar(&labelVar, "label", "", "Disk label to apply")
+	flag.StringVar(&fsTypeVar, "type", "ext4", "Type of filesystem to create")
+}
+
+func main() {
+	flag.Parse()
+
+	findDrives()
+
+	if flag.NArg() > 1 {
+		log.Fatalf("Too many arguments provided")
+	}
+
+	if flag.NArg() == 0 {
+		if err := autoformat(labelVar, fsTypeVar); err != nil {
+			log.Fatalf("%v", err)
+		}
+	} else {
+		if err := format(flag.Args()[0], labelVar, fsTypeVar); err != nil {
+			log.Fatalf("%v", err)
+		}
+	}
+}

pkg/format/format.sh

@@ -1,116 +0,0 @@
-#!/bin/sh
-
-# this script assumes anything on the disk can be removed if corrupted
-# other use cases may need different scripts.
-
-# currently only supports ext4 but should be expanded
-
-do_fsck()
-{
-	# preen
-	/sbin/e2fsck -p $*
-	EXIT_CODE=$?
-	# exit code 1 is errors corrected
-	[ "${EXIT_CODE}" -eq 1 ] && EXIT_CODE=0
-	# exit code 2 or 3 means need to reboot
-	[ "${EXIT_CODE}" -eq 2 -o "${EXIT_CODE}" -eq 3 ] && /sbin/reboot
-	# exit code 4 or over is fatal
-	[ "${EXIT_CODE}" -lt 4 ] && return "${EXIT_CODE}"
-
-	# try harder
-	/sbin/e2fsck -y $*
-	# exit code 1 is errors corrected
-	[ "${EXIT_CODE}" -eq 1 ] && EXIT_CODE=0
-	# exit code 2 or 3 means need to reboot
-	[ "${EXIT_CODE}" -eq 2 -o "${EXIT_CODE}" -eq 3 ] && /sbin/reboot
-	# exit code 4 or over is fatal
-	[ "${EXIT_CODE}" -ge 4 ] && printf "Filesystem unrecoverably corrupted, will reformat\n"
-
-	return "${EXIT_CODE}"
-}
-
-do_fsck_extend_mount()
-{
-	DRIVE="$1"
-	DATA="$2"
-
-	do_fsck "$DATA" || return 1
-
-	# only try to extend if there is a single partition and free space
-	PARTITIONS=$(sfdisk -J "$DRIVE" | jq '.partitiontable.partitions | length')
-
-	if [ "$PARTITIONS" -eq 1 ] && \
-		sfdisk -F "$DRIVE" | grep -q 'Unpartitioned space' &&
-		! sfdisk -F "$DRIVE" | grep -q '0 B, 0 bytes, 0 sectors'
-	then
-		SPACE=$(sfdisk -F "$DRIVE" | grep 'Unpartitioned space')
-		printf "Resizing disk partition: $SPACE\n"
-
-		# 83 is Linux partition id
-		START=$(sfdisk -J "$DRIVE" | jq -e '.partitiontable.partitions | map(select(.type=="83")) | .[0].start')
-
-		sfdisk -q --delete "$DRIVE" 2> /dev/null
-		echo "${START},,83;" | sfdisk -q "$DRIVE"
-
-		# set bootable flag
-		sfdisk -A "$DRIVE" 1
-
-		# update status
-		blockdev --rereadpt $diskdev 2> /dev/null
-		mdev -s
-
-		# wait for device
-		for i in $(seq 1 50); do test -b "$DATA" && break || sleep .1; mdev -s; done
-
-		# resize2fs fails unless we use -f here
-		do_fsck -f "$DATA" || return 1
-		resize2fs "$DATA"
-
-		do_fsck "$DATA" || return 1
-	fi
-}
-
-do_mkfs()
-{
-	diskdev="$1"
-
-	# new disks does not have an DOS signature in sector 0
-	# this makes sfdisk complain. We can workaround this by letting
-	# fdisk create that DOS signature, by just do a "w", a write.
-	# http://bugs.alpinelinux.org/issues/145
-	echo "w" | fdisk $diskdev >/dev/null
-
-	# format one large partition
-	echo ";" | sfdisk --quiet $diskdev
-
-	# update status
-	blockdev --rereadpt $diskdev 2> /dev/null
-
-	# wait for device
-	for i in $(seq 1 50); do test -b "$DATA" && break || sleep .1; mdev -s; done
-
-	FSOPTS="-O resize_inode,has_journal,extent,huge_file,flex_bg,uninit_bg,64bit,dir_nlink,extra_isize"
-
-	mkfs.ext4 -q -F $FSOPTS ${diskdev}1
-}
-
-# TODO fix for multiple disks, cdroms etc
-DEV="$(find /dev -maxdepth 1 -type b ! -name 'loop*' | grep -v '[0-9]$' | sed 's@.*/dev/@@' | sort | head -1 )"
-
-[ -z "${DEV}" ] && exit 1
-
-DRIVE="/dev/${DEV}"
-
-# see if it has a partition table already
-if sfdisk -d "${DRIVE}" >/dev/null 2>/dev/null
-then
-	DATA=$(sfdisk -J "$DRIVE" | jq -e -r '.partitiontable.partitions | map(select(.type=="83")) | .[0].node')
-	if [ $? -eq 0 ]
-	then
-		do_fsck_extend_mount "$DRIVE" "$DATA" || do_mkfs "$DRIVE"
-	else
-		do_mkfs "$DRIVE"
-	fi
-else
-	do_mkfs "$DRIVE"
-fi