sonic-buildimage/files/initramfs-tools/varlog

#!/bin/sh -e

PREREQS=""

prereqs() { echo "$PREREQS"; }

case $1 in
  prereqs)
  prereqs
    exit 0
    ;;
esac

logs_inram=false

# Extract kernel parameters
set -- $(cat /proc/cmdline)
for x in "$@"; do
    case "$x" in
        varlog_size=*)
            varlog_size="${x#varlog_size=}"
            ;;
        logs_inram=on)
            logs_inram=true
            ;;
    esac
done

[ -z "$varlog_size" ] && exit 0

# If logs are being stored in memory, then don't bother
# creating the log file just to have it deleted afterwards.
$logs_inram && exit 0

# exit when the var_log.ext4 exists and the size matches
if [ -e "${rootmnt}/host/disk-img/var-log.ext4" ]; then
    cur_varlog_size=$(ls -l ${rootmnt}/host/disk-img/var-log.ext4 | awk '{print $5}')
    if [ $cur_varlog_size == $((1024*1024*$varlog_size)) ]; then
        exit 0
    else
        rm -rf ${rootmnt}/host/disk-img
    fi
fi

# create varlog disk
case "${ROOT}" in 
    ubi*)
        # sys_fallocate is NOT supported over UBIFS
        mkdir -p ${rootmnt}/host/disk-img && ${rootmnt}/usr/bin/truncate -s "$varlog_size"M ${rootmnt}/host/disk-img/var-log.ext4 && mkfs.ext4 -q -F ${rootmnt}/host/disk-img/var-log.ext4
        ;;
    *)
        mkdir -p ${rootmnt}/host/disk-img && ${rootmnt}/usr/bin/fallocate -l "$varlog_size"M ${rootmnt}/host/disk-img/var-log.ext4 && mkfs.ext4 -q -F ${rootmnt}/host/disk-img/var-log.ext4
        ;;
esac