linux-live/livekitlib

#!/bin/sh
 
# Functions library :: for Linux Live Kit scripts
# Author: Tomas M. <http://www.linux-live.org>
#
 
# =================================================================
# debug and output functions
# =================================================================
 
# global variable
DEBUG_IS_ENABLED="$(cat /proc/cmdline 2>/dev/null | grep debug)"
 
debug_log()
{
if [ "$DEBUG_IS_ENABLED" ]; then
echo "- debug: $*" >&2
log "- debug: $*"
fi
}
 
# header
# $1 = text to show
#
header()
{
echo """$@"""
}
 
 
# echogreen will echo $@ in green color
# $1 = text
#
echogreen()
{
echo -ne """$@"""
}
 
# log - store given text in /var/log/livedbg
log()
{
echo "$@" 2>/dev/null >>/var/log/livedbg
}
 
# show information about the debug shell
show_debug_banner()
{
echo
echo "====="
echo ": Debugging started. Here is the root shell for you."
echo ": Type your desired commands or hit Ctrl+D to continue booting."
echo
}
 
# debug_shell
# executed when debug boot parameter is present
#
debug_shell()
{
if [ "$DEBUG_IS_ENABLED" ]; then
show_debug_banner
sh < /dev/console
echo
fi
}
 
fatal()
{
echolog
header "Fatal error occured - $1"
echolog "Something went wrong and we can't continue. This should never happen."
echolog "Please reboot your computer with Ctrl+Alt+Delete ..."
echolog
sh < /dev/console
}
 
 
# test if the script is started by root user. If not, exit
#
allow_only_root()
{
if [ "0$UID" -ne 0 ]; then
echo "Only root can run $(basename $0)"; exit 1
fi
}
 
# Create bundle
# call mksquashfs with apropriate arguments
# $1 = directory which will be compressed to squashfs bundle
# $2 = output file
# $3..$9 = optional arguments like -keep-as-directory or -b 123456789
#
create_bundle()
{
debug_log "create_module" "$*"
rm -f "$2" # overwrite, never append to existing file
mksquashfs "$1" "$2" -comp xz -b 512K $3 $4 $5 $6 $7 $8 $9>/dev/null
}
 
# mount virtual filesystems like proc etc
#
init_proc()
{
debug_log "vfs_mount_init"
mount -n -t proc proc /proc
echo "0" >/proc/sys/kernel/printk
mount -n -t sysfs sysfs /sys
mount -n -o remount,rw rootfs /
ln -sf /proc/mounts /etc/mtab
}
 
# make sure some devices are there
init_devs()
{
echo /sbin/mdev > /proc/sys/kernel/hotplug
mdev -s
modprobe zram 2>/dev/null
modprobe loop 2>/dev/null
modprobe squashfs 2>/dev/null
}
 
# Activate zram (auto-compression of RAM)
# Compressed RAM consumes 1/2 or even 1/4 of original size
# Setup static size of 500MB
#
init_zram()
{
debug_log "init_zram"
echo "Setting dynamic RAM compression using ZRAM"
echo 536870912 > /sys/block/zram0/disksize # 512MB
mkswap /dev/zram0
swapon /dev/zram0 -p 32767
echo 100 > /proc/sys/vm/swappiness
}
 
# load the AUFS kernel module if needed
#
init_aufs()
{
debug_log "init_aufs"
# TODO maybe check here if aufs support is working at all
# and procude useful error message if user has no aufs
modprobe aufs 2>/dev/null
}
 
# Setup empty union
# $1 = memory directory (tmpfs will be mounted there)
# $2 = union directory where to mount the union
#
init_union()
{
debug_log "init_union"
mkdir -p "$1"
mkdir -p "$2"
mount -t aufs -o xino="$1/.xino",br="$1" none "$2"
}
 
# Make sure to mount FAT12/16/32 using vfat
# in order to support long filenames
# $1 = device
#
device_bestfs()
{
debug_log "device_bestfs"
local PEEK
 
PEEK="$(dd if="$1" bs=1k count=1 2>/dev/null | strings)"
if [ "$(echo "$PEEK" | egrep -i "FAT[13][26]")" != "" ]; then
echo "-t vfat"
# TODO: this will work only with fuse
# else if [ "$(echo "$PEEK" | egrep -i 'NTFS')" != "" ]; then
# echo "-t ntfs-3g"
fi
}
 
# Find LIVEKIT data by mounting all devices
# If found, retain mounted disk
# $1 = data directory to mount
#
find_data()
{
debug_log "find_data"
 
local DEVICE FS MNT
 
mkdir -p "$1"
blkid | sort | cut -d: -f 1 | while read DEVICE; do
FS="$(device_bestfs "$DEVICE")"
mount -r "$DEVICE" "$1" $FS
if [ -d "$1/$LIVEKITNAME" ]; then
echo "$1/$LIVEKITNAME"
return
fi
umount "$1" 2>/dev/null
done
}
 
# Mount squashfs filesystem bundles
# and add them to union
# $1 = directory where to search for bundles
# $2 = directory where to mount bundles
# $3 = directory where union is mounted
#
union_append_bundles()
{
ls -1 "$1" | grep '.sb$' | sort | while read BUNDLE; do
mkdir -p "$2/$BUNDLE"
mount -o loop -t squashfs "$1/$BUNDLE" "$2/$BUNDLE"
mount -o remount,add:1:"$2/$BUNDLE" none "$3"
done
}
 
# Create empty fstab properly
# $1 = root directory
#
fstab_create()
{
local FSTAB
FSTAB="$1/etc/fstab"
echo aufs / aufs defaults 0 0 > $FSTAB
echo proc /proc proc defaults 0 0 >> $FSTAB
echo sysfs /sys sysfs defaults 0 0 >> $FSTAB
echo devpts /dev/pts devpts gid=5,mode=620 0 0 >> $FSTAB
echo tmpfs /dev/shm tmpfs defaults 0 0 >> $FSTAB
}
 
 
# Change root and execute init
# $1 = where to change root
#
change_root()
{
cd "$1"
 
# make sure important devices are in union
if [ ! -e dev/console ]; then mknod dev/console c 5 1; fi
if [ ! -e dev/null ]; then mknod dev/null c 1 3; fi
 
# find chroot and init
if [ -x bin/chroot ]; then CHROOT=bin/chroot; fi
if [ -x sbin/chroot ]; then CHROOT=sbin/chroot; fi
if [ -x usr/bin/chroot ]; then CHROOT=usr/bin/chroot; fi
if [ -x usr/sbin/chroot ]; then CHROOT=usr/sbin/chroot; fi
if [ "$CHROOT" = "" ]; then fatal "Can't find executable chroot command"; fi
 
if [ -x bin/init ]; then INIT=bin/init; fi
if [ -x sbin/init ]; then INIT=sbin/init; fi
if [ "$INIT" = "" ]; then fatal "Can't find executable init command"; fi
 
mkdir -p mnt/memory
mount -n -o remount,ro aufs .
pivot_root . mnt/memory
exec $CHROOT . $INIT <dev/console >dev/console 2>&1
# exec switch_root -c /dev/console . $INIT
}