scripts/casper

   1 #!/bin/sh
   2
   3 # set -e
   4
   5 export PATH=/root/usr/bin:/root/usr/sbin:/root/bin:/root/sbin:/usr/bin:/usr/sbin:/bin:/sbin
   6
   7 mountpoint=/cdrom
   8
   9 mkdir -p $mountpoint
  10
  11 overlay_method=unionfs
  12 if [ "${DPKG_ARCH}" = "ia64" ] || [ "${DPKG_ARCH}" = "hppa" ] || [ "${DPKG_ARCH}" = "sparc" ]; then
  13     overlay_method=devmapper
  14 fi
  15
  16 USERNAME=ubuntu
  17 USERFULLNAME="Ubuntu LiveCD user"
  18 HOST=ubuntu
  19
  20 [ -f /etc/casper.conf ] && . /etc/casper.conf
  21
  22 export USERNAME USERFULLNAME HOST
  23
  24 casper_path() {
  25     path=$1
  26     if [ -e "$path/casper/filesystem.cloop" ]; then
  27         echo "$path/casper/filesystem.cloop"
  28         return 0
  29     elif [ -e "$path/casper/filesystem.squashfs" ]; then
  30         echo "$path/casper/filesystem.squashfs"
  31         return 0
  32     fi
  33     return 1
  34 }
  35
  36 subdevices() {
  37     sysblock=$1
  38     r=""
  39     for dev in "${sysblock}" "${sysblock}"/*; do
  40         if [ -e "${dev}/dev" ]; then
  41             r="${r} ${dev}"
  42         fi
  43     done
  44     echo ${r}
  45 }
  46
  47 get_backing_device() {
  48         case "$1" in
  49             *.cloop)
  50                 echo $(setup_loop "$1" "cloop" "/sys/block/cloop*")
  51                         ;;
  52             *.squashfs)
  53                 echo $(setup_loop "$1" "loop" "/sys/block/loop*")
  54                 ;;
  55             *)
  56                 panic "Unrecognized casper filesystem: $1"
  57                 ;;
  58         esac
  59 }
  60
  61 setup_cow() {
  62         case "$1" in
  63             unionfs)
  64                 setup_unionfs "$2" "$rootmnt"
  65                 ;;
  66             devmapper)
  67                 setup_devmapper "$2" "$rootmnt"
  68         esac
  69 }
  70
  71 sys2dev() {
  72     sysdev=${1#/sys}
  73     echo "/dev/$(udevinfo -q name -p ${sysdev} 2>/dev/null|| echo ${sysdev##*/})"
  74 }
  75
  76 setup_loop() {
  77     local fspath=$1
  78     local module=$2
  79     local pattern=$3
  80
  81     modprobe -Qb "$module"
  82     udevplug -W
  83
  84     for loopdev in $pattern; do
  85         if [ "$(cat $loopdev/size)" -eq 0 ]; then
  86             dev=$(sys2dev "${loopdev}")
  87             losetup "$dev" "$fspath"
  88             echo "$dev"
  89             return 0
  90         fi
  91     done
  92     panic "No loop devices available"
  93 }
  94
  95 get_fstype() {
  96     local FSTYPE
  97     local FSSIZE
  98     eval $(fstype < $1)
  99     if [ "$FSTYPE" != "unknown" ]; then
 100         echo $FSTYPE
 101         return 0
 102     fi
 103     /lib/udev/vol_id -t $1 2>/dev/null
 104 }
 105
 106 setup_devmapper() {
 107     backdev="$1"
 108     rootmnt="$2"
 109
 110     modprobe -Qb dm-mod
 111     COW_DEVICE=/dev/ram1
 112     COW_NAME="casper-cow"
 113
 114     BACKING_FILE_SIZE=$(blockdev --getsize "$backdev")
 115     MAX_COW_SIZE=$(blockdev --getsize "$COW_DEVICE")
 116     CHUNK_SIZE=8 # sectors
 117
 118     if [ -z "$COW_SIZE" -o "$COW_SIZE" -gt "$MAX_COW_SIZE" ]; then
 119         COW_SIZE=$MAX_COW_SIZE
 120     fi
 121
 122     echo "0 $COW_SIZE linear $COW_DEVICE 0" | dmsetup create $COW_NAME
 123
 124     echo "0 $BACKING_FILE_SIZE snapshot $backdev /dev/mapper/$COW_NAME p $CHUNK_SIZE" | \
 125         dmsetup create casper-snapshot
 126     if [ "$(get_fstype $backdev)" = "unknown" ]; then
 127         panic "Unknown file system type on $backdev"
 128     fi
 129     mount -t $(get_fstype "$backdev") /dev/mapper/casper-snapshot $rootmnt || panic "Can not mount /dev/mapper/casper/snapshot on $rootmnt"
 130
 131     mkdir -p "$rootmnt/rofs"
 132     echo "0 $BACKING_FILE_SIZE linear $backdev 0" | dmsetup create casper-backing
 133     mount -t $(get_fstype "$backdev") /dev/mapper/casper-backing "$rootmnt/rofs"
 134 }
 135
 136 where_is_mounted() {
 137     device=$1
 138     if grep -q "^$device " /proc/mounts; then
 139         grep "^$device " /proc/mounts | read d mountpoint rest
 140         echo $mountpoint
 141         return 0
 142     fi
 143     return 1
 144 }
 145
 146 find_cow_device() {
 147     for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
 148         for dev in $(subdevices "${sysblock}"); do
 149             devname=$(sys2dev "${dev}")
 150             if [ "$(/lib/udev/vol_id -l $devname 2>/dev/null)" = "casper-rw" ]; then
 151                 echo "$devname"
 152                 return
 153             elif [ "$(get_fstype ${devname})" = "vfat" ]; then
 154                 mkdir -p /cow-backing
 155                 if where_is_mounted ${devname} > /dev/null; then
 156                     mount -o remount,rw ${devname} $(where_is_mounted ${devname}) || panic "Remounting failed"
 157                     mount -o bind $(where_is_mounted ${devname}) /cow-backing || panic "Cannot bind-mount"
 158                 else
 159                     mount -t $(get_fstype "${devname}") -o rw "${devname}" /cow-backing || panic "Cannot mount $devname on /cow-backing"
 160                 fi
 161
 162                 if [ -e "/cow-backing/casper-rw" ]; then
 163                     echo $(setup_loop "/cow-backing/casper-rw" "loop" "/sys/block/loop*")
 164                     return 0
 165                 else
 166                     umount /cow-backing
 167                 fi
 168             fi
 169
 170         done
 171     done
 172     return 1
 173 }
 174
 175 setup_unionfs() {
 176         backdev="$1"
 177         rootmnt="$2"
 178         modprobe -Qb unionfs
 179         mkdir -p /cow
 180
 181         if grep -q persistent /proc/cmdline; then
 182             i=0
 183             # We love udev and the kernel!
 184             while [ "$i" -lt 300 ]; do
 185                 cowdevice=$(find_cow_device)
 186                 if [ -b "$cowdevice" ]; then
 187                     mount -t $(get_fstype "$cowdevice") -o rw "$cowdevice" /cow || panic "Can not mount $cowdevice on /cow"
 188                     break
 189                 fi
 190                 sleep 5
 191 #                sleep 0.1
 192                 i=$(( $i + 1 ))
 193             done
 194         else
 195             mount -t tmpfs tmpfs /cow
 196         fi
 197
 198         mkdir -p /rofs
 199     if [ "$(get_fstype $backdev)" = "unknown" ]; then
 200         panic "Unknown file system type on $backdev"
 201     fi
 202         mount -t $(get_fstype "$backdev") -o ro "$backdev" /rofs || panic "Can not mount $backdev on /rofs"
 203
 204         mount -t unionfs -o dirs=/cow=rw:/rofs=ro unionfs "$rootmnt"
 205         if grep -q show-cow /proc/cmdline; then
 206             mkdir -p "$rootmnt/cow"
 207             mount -o bind /cow "$rootmnt/cow"
 208         fi
 209         mkdir -p "$rootmnt/rofs"
 210         mount -o bind /rofs "$rootmnt/rofs"
 211 }
 212
 213 is_usb_device() {
 214     sysfs_path="${1#/sys}"
 215     if /lib/udev/path_id "${sysfs_path}" | grep -q "ID_PATH=usb"; then
 216         return 0
 217     fi
 218     return 1
 219 }
 220
 221 find_cd() {
 222         mounted=
 223         for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop | grep -v ram); do
 224             devname=$(sys2dev "${sysblock}")
 225             fstype=$(get_fstype "${devname}")
 226             if /lib/udev/cdrom_id ${devname} > /dev/null; then
 227                 mount -t ${fstype} -o ro "$devname" $mountpoint || continue
 228                 if casper_path $mountpoint; then
 229                     echo $(casper_path $mountpoint)
 230                     return
 231                 else
 232                     umount $mountpoint
 233                 fi
 234             elif is_usb_device "$sysblock"; then
 235                 for dev in $(subdevices "${sysblock}"); do
 236                     devname=$(sys2dev "${dev}")
 237                     fstype=$(get_fstype "${devname}")
 238                     case ${fstype} in
 239                         vfat|iso9660|udf)
 240                             mount -t ${fstype} -o ro "${devname}" $mountpoint || continue
 241                             if casper_path $mountpoint; then
 242                                 echo $(casper_path $mountpoint)
 243                                 return
 244                             else
 245                                 umount $mountpoint
 246                             fi
 247                             ;;
 248                     esac
 249                 done
 250             elif [ "${fstype}" = "squashfs" ]; then
 251
 252                 # This is an ugly hack situation, the block device has
 253                 # a squashfs image directly on it.  It's hopefully
 254                 # casper, so take it and run with it.
 255
 256                 ln -s "${devname}" "${devname}.${fstype}"
 257                 echo "${devname}.${fstype}"
 258                 return
 259             fi
 260         done
 261 }
 262
 263 set_usplash_timeout() {
 264     if [ -x /sbin/usplash_write ]; then
 265         /sbin/usplash_write "TIMEOUT 120"
 266     fi
 267 }
 268
 269 mountroot() {
 270     exec 6>&1
 271     exec 7>&2
 272     exec > casper.log
 273     exec 2>&1
 274
 275     set_usplash_timeout
 276     [ "$quiet" != "y" ] && log_begin_msg "Running /scripts/casper-premount"
 277     run_scripts /scripts/casper-premount
 278     [ "$quiet" != "y" ] && log_end_msg
 279
 280     # Needed here too because some things (*cough* udev *cough*)
 281     # changes the timeout
 282
 283     set_usplash_timeout
 284
 285     for i in 0 1 2 3 4 5 6 7 8 9 a b c d e f 10 11 12 13; do
 286         live_image=$(find_cd)
 287         if [ "${live_image}" ]; then
 288             break
 289         fi
 290         sleep 1
 291     done
 292     if [ "$?" -gt 0 ]; then
 293         panic "Unable to find a CD-ROM containing a live file system"
 294     fi
 295
 296     setup_cow "$overlay_method" "$(get_backing_device $live_image)" "$rootmnt"
 297
 298     log_end_msg
 299
 300     maybe_break casper-bottom
 301     [ "$quiet" != "y" ] && log_begin_msg "Running /scripts/casper-bottom"
 302
 303     run_scripts /scripts/casper-bottom
 304     [ "$quiet" != "y" ] && log_end_msg
 305
 306     exec 1>&6 6>&-
 307     exec 2>&7 7>&-
 308     cp casper.log "${rootmnt}/var/log/"
 309 }