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=casper
  17 USERFULLNAME="Live session user"
  18 HOST=live
  19
  20 [ -f /etc/casper.conf ] && . /etc/casper.conf
  21
  22 export USERNAME USERFULLNAME HOST
  23
  24 is_casper_path() {
  25     path=$1
  26     if [ -d "$path/casper" ]; then
  27         if [ "$(echo $path/casper/*.cloop)" != "$path/casper/*.cloop" ] ||
  28             [ "$(echo $path/casper/*.squashfs)" != "$path/casper/*.squashfs" ]; then
  29             return 0
  30         fi
  31     fi
  32     return 1
  33 }
  34
  35 subdevices() {
  36     sysblock=$1
  37     r=""
  38     for dev in "${sysblock}" "${sysblock}"/*; do
  39         if [ -e "${dev}/dev" ]; then
  40             r="${r} ${dev}"
  41         fi
  42     done
  43     echo ${r}
  44 }
  45
  46 get_backing_device() {
  47         case "$1" in
  48             *.cloop)
  49                 echo $(setup_loop "$1" "cloop" "/sys/block/cloop*")
  50                         ;;
  51             *.squashfs)
  52                 echo $(setup_loop "$1" "loop" "/sys/block/loop*")
  53                 ;;
  54             *)
  55                 panic "Unrecognized casper filesystem: $1"
  56                 ;;
  57         esac
  58 }
  59
  60 match_files_in_dir() {
  61     # Does any files match pattern $1 ?
  62
  63     local pattern="$1"
  64     if [ "$(echo $pattern)" != "$pattern" ]; then
  65         return 0
  66     fi
  67     return 1
  68 }
  69
  70 mount_images_in_directory() {
  71     directory="$1"
  72     rootmnt="$2"
  73     if match_files_in_dir "$directory/casper/*.cloop"; then
  74         # Let's hope there's just one matching *.cloop... FIXME
  75         setup_devmapper $(get_backing_device "$directory/casper/*.cloop") "$rootmnt"
  76     elif match_files_in_dir "$directory/casper/*.squashfs"; then
  77         setup_unionfs "$directory/casper" "$rootmnt"
  78     else
  79         :
  80     fi
  81 }
  82
  83 sys2dev() {
  84     sysdev=${1#/sys}
  85     echo "/dev/$(udevinfo -q name -p ${sysdev} 2>/dev/null|| echo ${sysdev##*/})"
  86 }
  87
  88 setup_loop() {
  89     local fspath=$1
  90     local module=$2
  91     local pattern=$3
  92
  93     modprobe -Qb "$module"
  94     udevplug -W
  95
  96     for loopdev in $pattern; do
  97         if [ "$(cat $loopdev/size)" -eq 0 ]; then
  98             dev=$(sys2dev "${loopdev}")
  99             losetup "$dev" "$fspath"
 100             echo "$dev"
 101             return 0
 102         fi
 103     done
 104     panic "No loop devices available"
 105 }
 106
 107 get_fstype() {
 108     local FSTYPE
 109     local FSSIZE
 110     eval $(fstype < $1)
 111     if [ "$FSTYPE" != "unknown" ]; then
 112         echo $FSTYPE
 113         return 0
 114     fi
 115     /lib/udev/vol_id -t $1 2>/dev/null
 116 }
 117
 118 setup_devmapper() {
 119     backdev="$1"
 120     rootmnt="$2"
 121
 122     modprobe -Qb dm-mod
 123     COW_DEVICE=/dev/ram1
 124     COW_NAME="casper-cow"
 125
 126     BACKING_FILE_SIZE=$(blockdev --getsize "$backdev")
 127     MAX_COW_SIZE=$(blockdev --getsize "$COW_DEVICE")
 128     CHUNK_SIZE=8 # sectors
 129
 130     if [ -z "$COW_SIZE" -o "$COW_SIZE" -gt "$MAX_COW_SIZE" ]; then
 131         COW_SIZE=$MAX_COW_SIZE
 132     fi
 133
 134     echo "0 $COW_SIZE linear $COW_DEVICE 0" | dmsetup create $COW_NAME
 135
 136     echo "0 $BACKING_FILE_SIZE snapshot $backdev /dev/mapper/$COW_NAME p $CHUNK_SIZE" | \
 137         dmsetup create casper-snapshot
 138     if [ "$(get_fstype $backdev)" = "unknown" ]; then
 139         panic "Unknown file system type on $backdev"
 140     fi
 141     mount -t $(get_fstype "$backdev") /dev/mapper/casper-snapshot $rootmnt || panic "Can not mount /dev/mapper/casper/snapshot on $rootmnt"
 142
 143     mkdir -p "$rootmnt/rofs"
 144     echo "0 $BACKING_FILE_SIZE linear $backdev 0" | dmsetup create casper-backing
 145     mount -t $(get_fstype "$backdev") /dev/mapper/casper-backing "$rootmnt/rofs"
 146 }
 147
 148 where_is_mounted() {
 149     device=$1
 150     if grep -q "^$device " /proc/mounts; then
 151         grep "^$device " /proc/mounts | read d mountpoint rest
 152         echo $mountpoint
 153         return 0
 154     fi
 155     return 1
 156 }
 157
 158 find_cow_device() {
 159     for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop); do
 160         for dev in $(subdevices "${sysblock}"); do
 161             devname=$(sys2dev "${dev}")
 162             if [ "$(/lib/udev/vol_id -l $devname 2>/dev/null)" = "casper-rw" ]; then
 163                 echo "$devname"
 164                 return
 165             elif [ "$(get_fstype ${devname})" = "vfat" ]; then
 166                 mkdir -p /cow-backing
 167                 if where_is_mounted ${devname} > /dev/null; then
 168                     mount -o remount,rw ${devname} $(where_is_mounted ${devname}) || panic "Remounting failed"
 169                     mount -o bind $(where_is_mounted ${devname}) /cow-backing || panic "Cannot bind-mount"
 170                 else
 171                     mount -t $(get_fstype "${devname}") -o rw "${devname}" /cow-backing || panic "Cannot mount $devname on /cow-backing"
 172                 fi
 173
 174                 if [ -e "/cow-backing/casper-rw" ]; then
 175                     echo $(setup_loop "/cow-backing/casper-rw" "loop" "/sys/block/loop*")
 176                     return 0
 177                 else
 178                     umount /cow-backing
 179                 fi
 180             fi
 181
 182         done
 183     done
 184     return 1
 185 }
 186
 187 setup_unionfs() {
 188     image_directory="$1"
 189     rootmnt="$2"
 190     modprobe -Qb unionfs
 191
 192     croot="" # Should really be /casper, but run-init doesn't handle
 193              # mount-points in subdirectories at all
 194
 195     # Let's just mount the read-only file systems first
 196     mkdir -p "${croot}"
 197     for image in "${image_directory}"/*.squashfs; do
 198         imagename=$(basename "${image}")
 199         backdev=$(get_backing_device "$image")
 200         fstype=$(get_fstype "${backdev}")
 201         if [ "${fstype}" = "unknown" ]; then
 202             panic "Unknown file system type on ${backdev} (${image})"
 203         fi
 204         mkdir -p "${croot}/${imagename}"
 205         mount -t "${fstype}" -o ro "${backdev}" "${croot}/${imagename}" || panic "Can not mount $backdev ($image) on ${croot}/${imagename}"
 206     done
 207
 208     rofsstring=""
 209     for dir in $(mount -t squashfs | cut -d\  -f 3); do
 210         rofsstring="$dir=ro:$rofsstring"
 211     done
 212     rofsstring=${rofsstring%:}
 213
 214     mkdir -p /cow
 215
 216     if grep -q persistent /proc/cmdline; then
 217         i=0
 218         # We love udev and the kernel!
 219         while [ "$i" -lt 300 ]; do
 220             cowdevice=$(find_cow_device)
 221             if [ -b "$cowdevice" ]; then
 222                 mount -t $(get_fstype "$cowdevice") -o rw "$cowdevice" /cow || panic "Can not mount $cowdevice on /cow"
 223                 break
 224             fi
 225             sleep 0.1
 226             i=$(( $i + 1 ))
 227         done
 228     else
 229         mount -t tmpfs tmpfs /cow
 230     fi
 231
 232     mount -t unionfs -o dirs=/cow=rw:$rofsstring unionfs "$rootmnt"
 233
 234     for d in $(mount -t squashfs | cut -d\  -f 3); do
 235         mkdir -p "${rootmnt}/casper/${d}"
 236         mount -o bind "${d}" "${rootmnt}/${d}"
 237         umount "${d}"
 238     done
 239
 240     if grep -q show-cow /proc/cmdline; then
 241         mkdir -p "$rootmnt/cow"
 242         mount -o bind /cow "$rootmnt/cow"
 243     fi
 244
 245 }
 246
 247 is_usb_device() {
 248     sysfs_path="${1#/sys}"
 249     if /lib/udev/path_id "${sysfs_path}" | grep -q "ID_PATH=(usb|pci-[^-]*-usb)"; then
 250         return 0
 251     fi
 252     return 1
 253 }
 254
 255 find_livefs() {
 256         mounted=
 257         for sysblock in $(echo /sys/block/* | tr ' ' '\n' | grep -v loop | grep -v ram); do
 258             devname=$(sys2dev "${sysblock}")
 259             fstype=$(get_fstype "${devname}")
 260             if /lib/udev/cdrom_id ${devname} > /dev/null; then
 261                 mount -t ${fstype} -o ro "$devname" $mountpoint || continue
 262                 if is_casper_path $mountpoint; then
 263                     echo $mountpoint
 264                     return
 265                 else
 266                     umount $mountpoint
 267                 fi
 268             elif is_usb_device "$sysblock"; then
 269                 for dev in $(subdevices "${sysblock}"); do
 270                     devname=$(sys2dev "${dev}")
 271                     fstype=$(get_fstype "${devname}")
 272                     case ${fstype} in
 273                         vfat|iso9660|udf)
 274                             mount -t ${fstype} -o ro "${devname}" $mountpoint || continue
 275                             if is_casper_path $mountpoint; then
 276                                 echo $mountpoint
 277                                 return
 278                             else
 279                                 umount $mountpoint
 280                             fi
 281                             ;;
 282                     esac
 283                 done
 284             elif [ "${fstype}" = "squashfs" ]; then
 285
 286                 # This is an ugly hack situation, the block device has
 287                 # a squashfs image directly on it.  It's hopefully
 288                 # casper, so take it and run with it.
 289
 290                 ln -s "${devname}" "${devname}.${fstype}"
 291                 echo "${devname}.${fstype}"
 292                 return
 293             fi
 294         done
 295 }
 296
 297 set_usplash_timeout() {
 298     if [ -x /sbin/usplash_write ]; then
 299         /sbin/usplash_write "TIMEOUT 120"
 300     fi
 301 }
 302
 303 mountroot() {
 304     exec 6>&1
 305     exec 7>&2
 306     exec > casper.log
 307     exec 2>&1
 308
 309     set_usplash_timeout
 310     [ "$quiet" != "y" ] && log_begin_msg "Running /scripts/casper-premount"
 311     run_scripts /scripts/casper-premount
 312     [ "$quiet" != "y" ] && log_end_msg
 313
 314     # Needed here too because some things (*cough* udev *cough*)
 315     # changes the timeout
 316
 317     set_usplash_timeout
 318
 319     for i in 0 1 2 3 4 5 6 7 8 9 a b c d e f 10 11 12 13; do
 320         livefs_root=$(find_livefs)
 321         if [ "${livefs_root}" ]; then
 322             break
 323         fi
 324         sleep 1
 325     done
 326     if [ "$?" -gt 0 ]; then
 327         panic "Unable to find a medium containing a live file system"
 328     fi
 329
 330     mount_images_in_directory "$livefs_root" "$rootmnt"
 331     log_end_msg
 332
 333     maybe_break casper-bottom
 334     [ "$quiet" != "y" ] && log_begin_msg "Running /scripts/casper-bottom"
 335
 336     run_scripts /scripts/casper-bottom
 337     [ "$quiet" != "y" ] && log_end_msg
 338
 339     exec 1>&6 6>&-
 340     exec 2>&7 7>&-
 341     cp casper.log "${rootmnt}/var/log/"
 342 }