#!/bin/bash

build() {
    local m=
    local -a md_devs mods

    add_if_avail() {
        local r= resolved=()

        # treat this as an alias, since ext3 might be aliased to ext4. also, as
        # of linux 3.9, we can find any filesystem by the alias "fs-$name"
        # rather than having to guess at the corresponding module name.
        IFS=$'\n' read -rd '' -a resolved < \
            <(modprobe -d "$_optmoduleroot" -S "$KERNELVERSION" -Ra {fs-,}"$1" 2>/dev/null)

        for r in "${resolved[@]}"; do
            _autodetect_cache["$r"]=1
        done
    }

    if [[ ! -d /sys/devices ]]; then
        error "/sys does not appear to be mounted. Unable to use autodetection"
        return 1
    fi

    mapfile -t mods < <(auto_modules)
    for m in "${mods[@]}"; do
        _autodetect_cache["$m"]=1
    done

    # detect filesystem for root
    if rootfstype=$(findmnt -uno fstype '/'); then
        add_if_avail "$rootfstype"
    else
        error "failed to detect root filesystem"
        fs_autodetect_failed=1
    fi

    # detect filesystem for separate /usr
    if usrfstype=$(findmnt -snero fstype --tab-file '/etc/fstab' -T '/usr'); then
        add_if_avail "$usrfstype"
    fi

    # scan for md raid devices
    md_devs=(/sys/class/block/md*/md/level)
    if [[ -e $md_devs ]]; then
        quiet "found %d mdadm arrays to scan" "${#md_devs[*]}"
        mapfile -t mods < <(awk '{ gsub(/raid[456]/, "raid456"); print; }' "${md_devs[@]}")
        for m in "${mods[@]}"; do
            _autodetect_cache["$m"]=1
        done
    fi

    if (( ${#_autodetect_cache[*]} )); then
        quiet "caching %d modules" "${#_autodetect_cache[*]}"
    fi
}

help() {
    cat <<HELPEOF
This hook shrinks your initramfs to a smaller size by autodetecting the needed
modules. Be sure to verify included modules are correct and none are missing.
This hook must be run before other subsystem hooks in order to take advantage
of auto-detection.  Any hooks placed before 'autodetect' will be installed in
full.
HELPEOF
}

# vim: set ft=sh ts=4 sw=4 et: