#!/bin/sh

toppid=$$
die() {
    fmt=$1
    shift
    printf "error building initramfs: $fmt\n" "$@" >&2
    kill "$toppid"
    trap '' EXIT
    exit 1
}

# generate a cpio entry for a command
gen_cmd() {
    cmd=$1
    cmdp="$(command -v "$cmd")" || die 'command not found: %s' "$cmd"
    # ignore builtins
    [ "$cmd" != "$cmdp" ] || return
    printf 'file %s %s 0755 0 0\n' "$cmdp" "$cmdp"
    ldd "$cmdp" | awk '/=>/ { print "file /lib64/" $1 " " $3 " 0755 0 0" }'
}

# generate the main file list
gen_cpio_list() {
    sed -e '/^#/d' cpio_list.txt
    tr ' ' '\n' < modules.dep | sed -e "s/://;s:.*:file /lib/modules/$KERNVER/& /lib/modules/$KERNVER/& 0644 0 0:"
    gen_cmd e2fsck
    gen_cmd dropbear
    gen_cmd cryptsetup
    ldconfig -p | awk '$1 == "libgcc_s.so.1" && $2 ~ /x86-64/ { print "file " $4 " " $4 " 0755 0 0" }'
}

# filter the list and insert parent directory entries
gen_dir_ents() {
    awk '{print; while (sub("/[^/]*$", "", $2) && $2) print "dir " $2 " 0755 0 0"; }'
}

# filter the list and generate the make dependency file
gen_depfile() {
    awk -v f=/dev/fd/3 -v deps="cpio_list.txt make" '
        { print }
        $1 == "file" { deps=deps " " $3; print $3 ":" > f }
        END { print "initramfs.img: " deps > f }
    '
}

if ! [ -e cpio_list.txt ] || ! [ -e gen_init_cpio ]; then
    cd "${0%/*}"
fi

gen_cpio_list | gen_dir_ents | sort -u | gen_depfile 3>initramfs.d | ./gen_init_cpio -t 0 - | $COMPRESSOR > initramfs.img