#!/bin/sh
# Copyright (c) 2020, The Linux Foundation. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
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#       with the distribution.
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#       from this software without specific prior written permission.
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# IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# Perform a bind mount, copying existing files as we do so to ensure the
#!/bin/sh
#
# Perform a bind mount, copying existing files as we do so to ensure the
# overlaid path has the necessary content.

if [ ! -e "$2" ]; then
   echo >&2 "No System file/directory exist"
   exit 1
fi
var_lib_path=/var/lib
volatile_lib_path=/var/volatile/lib

spec=$1
mountpoint=$2

if [ -f "$mountpoint" ]; then
    #Skip if already mount-binded
    if grep -qs $mountpoint /proc/mounts; then
        exit 0
    fi

    if [ ! -f "$spec" ]; then
        mkdir -p $(dirname $spec)
        cp -P --preserve=all "$mountpoint" "$spec"
    fi

    mount -o "bind" "$spec" "$mountpoint"
    test ! -x /sbin/restorecon || /sbin/restorecon "$mountpoint"
fi

if [ -d "$mountpoint" ]; then
    mkdir -p $spec
    cd $mountpoint
    for file in *
    do
        #Skip if already mount-binded
        # remove trailing '/' if present
        mountpath=$(echo $mountpoint | sed 's:/*$::')
        if grep -qs "$mountpath/$file" /proc/mounts; then
            continue
        fi

        if [ -f "$mountpoint/$file" ]; then
            if [ ! -f "$spec/$file" ]; then
                cp --preserve=all "$file" "$spec/"
            fi
            mount -o "bind" "$spec/$file" "$mountpoint/$file"
            test ! -x /sbin/restorecon || /sbin/restorecon "$mountpoint/$file"
        elif [[ "$mountpoint" == "$var_lib_path" ]] && [[ "$spec" == "$volatile_lib_path" ]]; then
            mountpath=$(echo $mountpoint | sed 's:/*$::')
            if grep -qs "$mountpath" /proc/mounts; then
                continue
            fi
            mount -o "bind" "$spec" "$mountpoint"
        fi
   done
fi
