#!/bin/bash
# This file is part of curtin. See LICENSE file for copyright and license info.

TEMP_D=""
CR="
"
VERBOSITY=${VERBOSITY:-${CURTIN_VERBOSITY:-0}}

error() { echo "$@" 1>&2; }
debug() {
    [ ${VERBOSITY:-0} -ge "$1" ] || return
    shift
    error "$@"
}

partition_main_usage() {
    cat <<EOF
Usage: ${0##*/} [ options ] target-dev

   partition target-dev with a single partition
   destroy any partition table that might be there already.

   options:
     -f | --format F   use partition table format F. [mbr, gpt, uefi, prep]
                       default mbr
     -E | --end E      end the partition at E (unit 1k bytes)
     -b | --boot       create a boot partition (512 MiB - default)
EOF
    [ $# -eq 0 ] || echo "$@"
}

cleanup() {
    if [ -d "$TEMP_D" ]; then
        rm -Rf "$TEMP_D"
    fi
}


wipe_partitions() {
    # wipe_partition(blockdev, ptno)
    local dev="" target="" ret="" part="" full="" out=""
    if [ "$1" = "--full" ]; then
        full="--full"
        shift
    fi
    dev="$1"
    shift
    for part in "$@"; do
        find_partno "$dev" $part ||
            { ret=$?; error "did not find $part on $dev"; return $ret; }
        target="$_RET"
        wipedev $full "$target" false false ||
            { ret=$?; error "failed to wipe $part on $dev"; return $ret; }
    done
    return 0
}

wipedev() {
    # wipedev([--full,] target, wipe_end=true, reread=true)
    # wipe the front and optionally end of $target
    # if reread=true call rereadpt and settle
    local full="0"
    if [ "$1" = "--full" ]; then
        full="1"
        shift
    fi
    local target="$1" wipe_end=${2:-true} rereadpt=${3:-true}
    local size="" out="" bs="" count="" seek="" mb=$((1024*1024))
    local info=""
    getsize "$target" ||
        { error "failed to get size of $target"; return 1; }
    size="$_RET"

    # select a block size that evenly divides size. bigger is generally faster.
    for bs in $mb 4096 1024 512 1; do
        [ "$((size % bs))" = "0" ] && break
    done
    if [ "$bs" = "1" ]; then
        error "WARN: odd sized '$target' ($size). not divisible by 512."
    fi

    if [ "$full" != "0" ]; then
        count=$((size / bs))
        info="size=$size conv=notrunc count=$count bs=$bs"
        debug 1 "wiping full '$target' with ${info}."
        out=$(LANG=C dd if=/dev/zero conv=notrunc "of=$target" \
            bs=$bs count=$count 2>&1) || {
            error "wiping entire '$target' with ${info} failed."
            error "$out"
            return 1
        }
    else
        local fbs=$bs
        count=$((size / bs))
        if [ "$size" -ge "$mb" ]; then
            count=1
            fbs=$mb
        fi
        info="size=$size count=$count bs=$fbs"
        debug 1 "wiping start of '$target' with ${info}."
        # wipe the first MB (up to 'size')
        out=$(dd if=/dev/zero conv=notrunc "of=$target" \
                "bs=$fbs" "count=$count" 2>&1) || {
            error "wiping start of '$target' with ${info} failed."
            error "$out"
            return 1
        }

        if $wipe_end && [ "$size" -gt "$mb" ]; then
            # do the last 1MB
            count=$((mb / bs))
            seek=$(((size / bs) - $count))
            info="size=$size count=$count bs=$bs seek=$seek"
            debug 1 "wiping end of '$target' with ${info}."
            out=$(dd if=/dev/zero conv=notrunc "of=$target" "seek=$seek" \
                "bs=$bs" "count=$count" 2>&1)
            if [ $? -ne 0 ]; then
                error "wiping end of '$target' with ${info} failed."
                error "$out";
                return 1;
            fi
        fi
    fi

    if $rereadpt && [ -b "$target" ]; then
        blockdev --rereadpt "$target"
        udevadm settle
    fi
}

find_partno() {
    local devname="$1" partno="$2"
    local devbname cand msg="" slash="/"
    devbname="${devname#/dev/}"
    # /dev/cciss/c0d0 -> ccis!c0d0
    devbname="${devbname//$slash/!}"
    if [ -d "/sys/class/block/${devbname}" ]; then
        local cand candptno name partdev
        debug 1 "using sys/class/block/$devbname"
        for cand in /sys/class/block/$devbname/*/partition; do
            [ -f "$cand" ] || continue
            read candptno < "$cand"
            [ "$candptno" = "$partno" ] || continue
            name=${cand#/sys/class/block/${devbname}/}
            name=${name%/partition}
            # ccis!c0d0p1 -> ccis/c0d0p1
            name=${name//!/$slash}
            partdev="/dev/$name"
            [ -b "$partdev" ] && _RET="$partdev" && return 0
            msg="expected $partdev to exist as partition $partno on $devname"
            error "WARN: $msg. it did not exist."
        done
    else
        for cand in "${devname}$partno" "${devname}p${partno}"; do
            [ -b "$cand" ] && _RET="$cand" && return 0
        done
    fi
    return 1
}

part2bd() {
    # part2bd given a partition, return the block device it is on
    # and the number the partition is.  ie, 'sda2' -> '/dev/sda 2'
    local dev="$1" fp="" sp="" bd="" ptnum=""
    dev="/dev/${dev#/dev/}"
    fp=$(readlink -f "$dev") || return 1
    sp="/sys/class/block/${fp##*/}"
    [ -f "$sp/partition" ] || { _RET="$fp 0"; return 0; }
    read ptnum < "$sp/partition"
    sp=$(readlink -f "$sp") || return 1
    # sp now has some /sys/devices/pci..../0:2:0:0/block/sda/sda1
    bd=${sp##*/block/}
    bd="${bd%/*}"
    _RET="/dev/$bd $ptnum"
    return 0
}

pt_gpt() {
    local target="$1" end=${2:-""} boot="$3" size="" s512=""
    local start="2048" rootsize="" bootsize="1048576" maxend=""
    local isblk=false
    getsize "$target" ||
        { error "failed to get size of $target"; return 1; }
    size="$_RET"
    if [ -z "$end" ]; then
        end=$(($size/512))
    else
        end=$(($end/512))
    fi

    if [ "$boot" = true ]; then
        maxend=$((($size/512)-$start-$bootsize))
        if [ $maxend -lt 0 ]; then
            error "Disk is not big enough for /boot partition on $target";
            return 1;
        fi
    else
        maxend=$((($size/512)-$start))
    fi
    [ "$end" -gt "$maxend" ] && end="$maxend"
    debug 1 "maxend=$maxend end=$end size=$size"

    [ -b "$target" ] && isblk=true

    if [ "$boot" = true ]; then
        # Creating 'efi', '/boot' and '/' partitions
        sgdisk --new "15:$start:+1M" --typecode=15:ef02 \
            --new "1::+512M" --typecode=1:8300 \
            --new "2::$end" --typecode=2:8300 "$target" ||
            { error "failed to gpt partition $target"; return 1; }
    else
        # Creating 'efi' and '/' partitions
        sgdisk --new "15:$start:+1M" --typecode=15:ef02 \
            --new "1::$end" --typecode=1:8300 "$target" ||
            { error "failed to gpt partition $target"; return 1; }
    fi

    if $isblk; then
        local expected="1 15"
        [ "$boot" = "true" ] && expected="$expected 2"
        blockdev --rereadpt "$target"
        udevadm settle
        assert_partitions "$target" $expected ||
            { error "$target missing partitions: $_RET"; return 1; }
        wipe_partitions "$target" $expected ||
            { error "$target: failed to wipe partitions"; return 1; }
    fi
}

assert_partitions() {
    local dev="$1" missing="" part=""
    shift
    for part in "$@"; do
        find_partno "$dev" $part || missing="${missing} ${part}"
    done
    _RET="${missing# }"
    [ -z "$missing" ]
}

pt_uefi() {
    local target="$1" end=${2:-""} size="" s512=""
    local start="2048" rootsize="" maxend=""
    local isblk=false
    getsize "$target" ||
        { error "failed to get size of $target"; return 1; }
    size="$_RET"
    if [ -z "$end" ]; then
        end=$(($size/512))
    else
        end=$(($end/512))
    fi

    maxend=$((($size/512)-$start))
    [ "$end" -gt "$maxend" ] && end="$maxend"
    debug 1 "maxend=$maxend end=$end size=$size"

    [ -b "$target" ] && isblk=true

    # Creating 'UEFI' and '/' partitions
    sgdisk --new "15:2048:+512M" --typecode=15:ef00 \
           --new "1::$end" --typecode=1:8300 "$target" ||
        { error "failed to sgdisk for uefi to $target"; return 1; }

    if $isblk; then
        blockdev --rereadpt "$target"
        udevadm settle
        assert_partitions "$target" 1 15 ||
            { error "$target missing partitions: $_RET"; return 1; }
        wipe_partitions "$target" 1 15 ||
            { error "$target: failed to wipe partitions"; return 1; }
    fi

    local pt15
    find_partno "$target" 15 && pt15="$_RET" ||
        { error "failed to find partition 15 for $target"; return 1; }
    mkfs -t vfat -F 32 -n uefi-boot "$pt15" ||
        { error "failed to partition :$pt15' for UEFI vfat"; return 1; }
}


pt_mbr() {
    local target="$1" end=${2:-""} boot="$3" size="" s512="" ptype="L"
    local start="2048" rootsize="" maxsize="4294967296"
    local maxend="" isblk=false def_bootsize="1048576" bootsize=0
    local isblk=false
    getsize "$target" ||
        { error "failed to get size of $target"; return 1; }
    size="$_RET"

    if $boot; then
        bootsize=$def_bootsize
    fi

    s512=$(($size/512))
    if [ $s512 -ge $maxsize ]; then
        debug 1 "disk is larger than max for mbr (2TB)"
        s512=$maxsize
    fi

    # allow 33 sectors for the secondary gpt header in the case that
    # the user wants to later 'sgdisk --mbrtogpt'
    local gpt2hsize="33"
    if [ -n "$end" ]; then
        rootsize=$(((end/512)-start-bootsize))
    else
        rootsize=$((s512-start-bootsize-$gpt2hsize))
    fi

    [ -b "$target" ] && isblk=true

    # interact with sfdisk in units of 512 bytes (--unit S)
    # we start all partitions at 2048 of those (1M)
    local sfdisk_out="" sfdisk_in="" sfdisk_cmd="" t="" expected=""
    if "$boot"; then
        t="$start,$bootsize,$ptype,-${CR}"
        t="$t$(($start+$bootsize)),$rootsize,$ptype,*"
        sfdisk_in="$t"
        expected="1 2"
    else
        sfdisk_in="$start,$rootsize,$ptype,*"
        expected=1
    fi
    sfdisk_cmd=( sfdisk --no-reread --force --Linux --unit S "$target" )
    debug 1 "sfdisking with: echo '$sfdisk_in' | ${sfdisk_cmd[*]}"
    sfdisk_out=$(echo "$sfdisk_in" | "${sfdisk_cmd[@]}" 2>&1)
    ret=$?
    [ $ret -eq 0 ] || {
        error "failed to partition $target [${sfdisk_out}]";
        return 1;
    }
    if $isblk; then
        blockdev --rereadpt "$target"
        udevadm settle
        assert_partitions "$target" ${expected} ||
            { error "$target missing partitions: $_RET"; return 1; }

        wipe_partitions "$target" ${expected} ||
            { error "failed to wipe partition 1 on $target"; return 1; }
    fi

}

pt_prep() {
    local target="$1" end=${2:-""}
    local cmd="" isblk=false
    [ -b "$target" ] && isblk=true

    local pprep="1" proot="2"
    wipedev "$target" ||
        { error "failed to clear $target"; return 1; }

    cmd=(
        sgdisk
           --new "${pprep}::+8M"  "--typecode=${pprep}:4100"
           --new "${proot}::$end" "--typecode=${proot}:8300"
           "$target"
    )
    debug 1 "partitioning '$target' with ${cmd[*]}"
    "${cmd[@]}" ||
        fail "Failed to create GPT partitions (${cmd[*]})"

    udevadm trigger
    udevadm settle

    if $isblk; then
        blockdev --rereadpt "$target"
        udevadm settle
        assert_partitions "$target" "${proot}" "${pprep}"  ||
            { error "$target missing partitions: $_RET"; return 1; }
        # wipe the full prep partition
        wipe_partitions --full "$target" "${pprep}" ||
            { error "$target: failed to wipe full PReP partition"; return 1;}
        wipe_partitions "$target" "${proot}" ||
            { error "$target: failed to wipe partition ${proot}"; return 1;}
    fi

    return 0
}

partition_main() {
    local short_opts="hE:f:bv"
    local long_opts="help,end:,format:,boot,verbose"
    local getopt_out=$(getopt --name "${0##*/}" \
        --options "${short_opts}" --long "${long_opts}" -- "$@") &&
        eval set -- "${getopt_out}" ||
        { partition_main_usage 1>&2; return 1; }

    local cur="" next=""
    local format="mbr" boot=false target="" end="" ret=0

    while [ $# -ne 0 ]; do
        cur="$1"; next="$2";
        case "$cur" in
            -h|--help) partition_main_usage ; exit 0;;
            -E|--end) end=$next; shift;;
            -f|--format) format=$next; shift;;
            -b|--boot) boot=true;;
            -v|--verbose) VERBOSITY=$((${VERBOSITY}+1));;
            --) shift; break;;
        esac
        shift;
    done

    [ $# -gt 1 ] && { partition_main_usage "got $# args, expected 1" 1>&2; return 1; }
    [ $# -eq 0 ] && { partition_main_usage "must provide target-dev" 1>&2; return 1; }
    target="$1"
    if [ -n "$end" ]; then
        human2bytes "$end" ||
            { error "failed to convert '$end' to bytes"; return 1; }
        end="$_RET"
    fi

    [ "$format" = "gpt" -o "$format" = "mbr" ] ||
        [ "$format" = "uefi" -o "$format" = "prep" ] ||
        { partition_main_usage "invalid format: $format" 1>&2; return 1; }

    TEMP_D=$(mktemp -d "${TMPDIR:-/tmp}/${0##*/}.XXXXXX") ||
        fail "failed to make tempdir"
    trap cleanup EXIT

    [ -e "$target" ] || { error "$target does not exist"; return 1; }
    [ -f "$target" -o -b "$target" ] ||
        { error "$target not a block device"; return 1; }

    wipedev "$target" ||
        { error "wiping $target failed"; return 1; }

    if [ "$format" = "mbr" ]; then
        pt_mbr "$target" "$end" "$boot"
    elif [ "$format" = "gpt" ]; then
        pt_gpt "$target" "$end" "$boot"
    elif [ "$format" = "uefi" ]; then
        pt_uefi "$target" "$end"
    elif [ "$format" = "prep" ]; then
        pt_prep "$target" "$end"
    fi
    ret=$?

    return $ret
}

human2bytes() {
    # converts size suitable for input to resize2fs to bytes
    # s:512 byte sectors, K:kilobytes, M:megabytes, G:gigabytes
    # none: block size of the image
    local input=${1} defunit=${2:-1024}
    local unit count;
    case "$input" in
        *s) count=${input%s}; unit=512;;
        *K) count=${input%K}; unit=1024;;
        *M) count=${input%M}; unit=$((1024*1024));;
        *G) count=${input%G}; unit=$((1024*1024*1024));;
        *)  count=${input}  ; unit=${defunit};;
    esac
   _RET=$((${count}*${unit}))
}

getsize() {
    # return size of target in bytes
    local target="$1"
    if [ -b "$target" ]; then
        _RET=$(blockdev --getsize64 "$target")
    elif [ -f "$target" ]; then
        _RET=$(stat "--format=%s" "$target")
    else
        return 1;
    fi
}

# vi: ts=4 expandtab syntax=sh