#! /bin/bash

IFS=$'\n'

# Extract all of the symbols provided by this module.

all_provides() {

    if [[ -n $(nm "$@" | sed -r -ne 's:^0*([0-9a-f]+) A __crc_(.+):0x\1 \2:p') ]]; then

        nm "$@" \

        | sed -r -ne 's:^0*([0-9a-f]+) A __crc_(.+):0x\1 \2:p' \

        | awk --non-decimal-data '{printf("0x%08x\t%s\n", $1, $2)}' \

        | LC_ALL=C sort -k2,2 -u

    else

        ELFRODATA=$(readelf -R .rodata "$@" | awk '/0x/{printf $2$3$4$5}')

        if [[ -n $(readelf -h "$@" | grep "little endian") ]]; then

            RODATA=$(echo $ELFRODATA | sed 's/\(..\)\(..\)\(..\)\(..\)/\4\3\2\1/g')

        else

            RODATA=$ELFRODATA

        fi

        for sym in $(nm "$@" | sed -r -ne 's:^0*([0-9a-f]+) R __crc_(.+):0x\1 \2:p'); do

            echo $sym $RODATA

        done \

        | awk --non-decimal-data '{printf("0x%08s\t%s\n", substr($3,($1*2)+1,8), $2)}' \

        | LC_ALL=C sort -k2,2 -u

    fi

}

# Extract all of the requirements of this module.

all_requires() {

    for module in "$@"; do

        set -- $(/sbin/modinfo -F vermagic "$module" | sed -e 's: .*::' -e q)

        /sbin/modprobe --dump-modversions "$module" \

        | awk --non-decimal-data '

            BEGIN { FS = "\t" ; OFS = "\t" }

            {printf("0x%08x\t%s\n", $1, $2)}' \

        | sed -r -e 's:$:\t'"$1"':'

    done \

    | LC_ALL=C sort -k2,2 -u

}

# Filter out requirements fulfilled by the module itself.

mod_requires() {

    LC_ALL=C join -t $'\t' -j 2 -v 1 \

        <(all_requires "$@") \

        <(all_provides "$@") \

    | LC_ALL=C sort -k1,1 -u

}

if ! [ -e /sbin/modinfo -a -e /sbin/modprobe ]; then

    cat > /dev/null

    exit 0

fi

modules=($(grep -E '/lib/modules/.+\.ko$'))

if [ ${#modules[@]} -gt 0 ]; then

    kernel=$(/sbin/modinfo -F vermagic "${modules[0]}" | sed -e 's: .*::' -e q)

    # get all that kernel provides

    symvers=$(mktemp -t ${0##*/}.XXXXX)

    cat /usr/src/kernels/$kernel/Module.symvers | awk '

        BEGIN { FS = "\t" ; OFS = "\t" }

        { print $2 "\t" $1 }

    ' \

    | sed -r -e 's:$:\t'"$kernel"':' \

    | LC_ALL=C sort -k1,1 -u > $symvers

    # Symbols matching with the kernel get a "kernel" dependency

    LC_ALL=C join -t $'\t' -j 1 $symvers <(mod_requires "${modules[@]}") | LC_ALL=C sort -u \

    | awk '{ FS = "\t" ; OFS = "\t" } { print "kernel(" $1 ") = " $2 }'

    # Symbols from elsewhere get a "ksym" dependency

    LC_ALL=C join -t $'\t' -j 1 -v 2 $symvers <(mod_requires "${modules[@]}") | LC_ALL=C sort -u \

    | awk '{ FS = "\t" ; OFS = "\t" } { print "ksym(" $1 ") = " $2 }'

fi