scripts/casper

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