#!/bin/sh

# Allow environment variables to override grep and config
: ${CONFIG:=/proc/config.gz}
: ${GREP:=zgrep}
: ${MODNAME:=configs}

SETCOLOR_SUCCESS="printf \\033[1;32m"
SETCOLOR_FAILURE="printf \\033[1;31m"
SETCOLOR_WARNING="printf \\033[1;33m"
SETCOLOR_NORMAL="printf \\033[0;39m"

is_set() {
    $GREP "$1=[y|m]" $CONFIG > /dev/null
    return $?
}

is_enabled() {
    mandatory=$2

    is_set $1
    RES=$?

    if [ $RES -eq 0 ]; then
        $SETCOLOR_SUCCESS && echo "enabled" && $SETCOLOR_NORMAL
    else
        if [ ! -z "$mandatory" -a "$mandatory" = yes ]; then
            $SETCOLOR_FAILURE && echo "required" && $SETCOLOR_NORMAL
        else
            $SETCOLOR_WARNING && echo "missing" && $SETCOLOR_NORMAL
        fi
    fi
}

if [ ! -f $CONFIG ]; then
    echo "Kernel configuration not found at $CONFIG; searching..."
    KVER="`uname -r`"
    HEADERS_CONFIG="/lib/modules/$KVER/build/.config"
    BOOT_CONFIG="/boot/config-$KVER"
    [ -f "${HEADERS_CONFIG}" ] && CONFIG=${HEADERS_CONFIG}
    [ -f "${BOOT_CONFIG}" ] && CONFIG=${BOOT_CONFIG}
    if [ ! -f "$CONFIG" ]; then
        MODULEFILE=$(modinfo -k $KVER -n $MODNAME 2> /dev/null)
        # don't want to modprobe, so give user a hint
        # altho scripts/extract-ikconfig could be used to extract contents without loading kernel module
        # http://svn.pld-linux.org/trac/svn/browser/geninitrd/trunk/geninitrd?rev=12696#L327
    fi
    GREP=grep
    if [ ! -f $CONFIG ]; then
        echo "$(basename $0): unable to retrieve kernel configuration" >&2
        echo >&2
        if [ -f "$MODULEFILE" ]; then
            echo "Try modprobe $MODNAME module, or" >&2
        fi
        echo "Try recompiling with IKCONFIG_PROC, installing the kernel headers," >&2
        echo "or specifying the kernel configuration path with:" >&2
        echo "  CONFIG=<path> $(basename $0)" >&2
        exit 1
    else
        echo "Kernel configuration found at $CONFIG"
    fi
fi

echo "--- Namespaces ---"
echo -n "Namespaces: " && is_enabled CONFIG_NAMESPACES yes
echo -n "Utsname namespace: " && is_enabled CONFIG_UTS_NS
echo -n "Ipc namespace: " && is_enabled CONFIG_IPC_NS yes
echo -n "Pid namespace: " && is_enabled CONFIG_PID_NS yes
echo -n "User namespace: " && is_enabled CONFIG_USER_NS
echo -n "Network namespace: " && is_enabled CONFIG_NET_NS
echo -n "Multiple /dev/pts instances: " && is_enabled DEVPTS_MULTIPLE_INSTANCES
echo
echo "--- Control groups ---"

print_cgroups() {
  # print all mountpoints for cgroup filesystems
  awk '$1 !~ /#/ && $3 == mp { print $2; } ; END { exit(0); } '  "mp=$1" "$2" ;
}

CGROUP_MNT_PATH=`print_cgroups cgroup /proc/self/mounts | head -n 1`
KVER_MAJOR=$($GREP '^# Linux.*Kernel Configuration' $CONFIG | \
    sed -r 's/.* ([0-9])\.[0-9]{1,2}\.[0-9]{1,3}.*/\1/')
if [ "$KVER_MAJOR" = "2" ]; then
KVER_MINOR=$($GREP '^# Linux.*Kernel Configuration' $CONFIG | \
    sed -r 's/.* 2.6.([0-9]{2}).*/\1/')
else
KVER_MINOR=$($GREP '^# Linux.*Kernel Configuration' $CONFIG | \
    sed -r 's/.* [0-9]\.([0-9]{1,3})\.[0-9]{1,3}.*/\1/')
fi

echo -n "Cgroup: " && is_enabled CONFIG_CGROUPS yes

if [ -f $CGROUP_MNT_PATH/cgroup.clone_children ]; then
    echo -n "Cgroup clone_children flag: " &&
    $SETCOLOR_SUCCESS && echo "enabled" && $SETCOLOR_NORMAL
else
    echo -n "Cgroup namespace: " && is_enabled CONFIG_CGROUP_NS yes
fi
echo -n "Cgroup device: " && is_enabled CONFIG_CGROUP_DEVICE
echo -n "Cgroup sched: " && is_enabled CONFIG_CGROUP_SCHED
echo -n "Cgroup cpu account: " && is_enabled CONFIG_CGROUP_CPUACCT
echo -n "Cgroup memory controller: "
if [ $KVER_MAJOR -ge 3 -a $KVER_MINOR -ge 6 ]; then
    is_enabled CONFIG_MEMCG
else
    is_enabled CONFIG_CGROUP_MEM_RES_CTLR
fi
is_set CONFIG_SMP && echo -n "Cgroup cpuset: " && is_enabled CONFIG_CPUSETS
echo
echo "--- Misc ---"
echo -n "Veth pair device: " && is_enabled CONFIG_VETH
echo -n "Macvlan: " && is_enabled CONFIG_MACVLAN
echo -n "Vlan: " && is_enabled CONFIG_VLAN_8021Q
echo -n "File capabilities: " && \
    ( [ "${KVER_MAJOR}" = 2 ] && [ ${KVER_MINOR} -lt 33 ] && \
       is_enabled CONFIG_SECURITY_FILE_CAPABILITIES ) || \
    ( ( [ "${KVER_MAJOR}" = "2" ] && [ ${KVER_MINOR} -gt 32 ] ) || \
         [ ${KVER_MAJOR} -gt 2 ] && $SETCOLOR_SUCCESS && \
         echo "enabled" && $SETCOLOR_NORMAL )

echo
echo "Note : Before booting a new kernel, you can check its configuration"
echo "usage : CONFIG=/path/to/config $0"
echo