207 lines
6.4 KiB
Bash
Executable File
207 lines
6.4 KiB
Bash
Executable File
#!/bin/bash
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# Buildroot wrapper to the collection of ext2/3/4 filesystem tools:
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# - genext2fs, to generate ext2 filesystem images
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# - tune2fs, to modify an ext2/3/4 filesystem (possibly in an image file)
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# - e2fsck, to check and fix an ext2/3/4 filesystem (possibly in an image file)
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set -e
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main() {
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local OPT OPTARG
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local nb_blocks nb_inodes nb_res_blocks root_dir image gen rev label uuid
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local -a genext2fs_opts
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local -a tune2fs_opts
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local tune2fs_O_opts
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# Default values
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gen=2
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rev=1
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while getopts :hb:i:r:d:o:G:R:l:u: OPT; do
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case "${OPT}" in
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h) help; exit 0;;
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b) nb_blocks=${OPTARG};;
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i) nb_inodes=${OPTARG};;
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r) nb_res_blocks=${OPTARG};;
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d) root_dir="${OPTARG}";;
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o) image="${OPTARG}";;
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G) gen=${OPTARG};;
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R) rev=${OPTARG};;
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l) label="${OPTARG}";;
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u) uuid="${OPTARG}";;
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:) error "option '%s' expects a mandatory argument\n" "${OPTARG}";;
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\?) error "unknown option '%s'\n" "${OPTARG}";;
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esac
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done
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# Sanity checks
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if [ -z "${root_dir}" ]; then
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error "you must specify a root directory with '-d'\n"
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fi
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if [ -z "${image}" ]; then
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error "you must specify an output image file with '-o'\n"
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fi
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case "${gen}:${rev}" in
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2:0|2:1|3:1|4:1)
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;;
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3:0|4:0)
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error "revision 0 is invalid for ext3 and ext4\n"
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;;
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*) error "unknown ext generation '%s' and/or revision '%s'\n" \
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"${gen}" "${rev}"
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;;
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esac
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# calculate needed inodes
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if [ -z "${nb_inodes}" ]; then
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nb_inodes=$(find "${root_dir}" | wc -l)
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nb_inodes=$((nb_inodes+400))
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fi
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# calculate needed blocks
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if [ -z "${nb_blocks}" ]; then
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# size ~= superblock, block+inode bitmaps, inodes (8 per block),
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# blocks; we scale inodes / blocks with 10% to compensate for
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# bitmaps size + slack
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nb_blocks=$(du -s -k "${root_dir}" |sed -r -e 's/[[:space:]]+.*$//')
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nb_blocks=$((500+(nb_blocks+nb_inodes/8)*11/10))
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fi
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# Upgrade to rev1 if needed
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if [ ${rev} -ge 1 ]; then
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tune2fs_O_opts+=",filetype"
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fi
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# Add a journal for ext3 and above
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if [ ${gen} -ge 3 ]; then
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tune2fs_opts+=( -j -J size=1 )
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# we add 1300 blocks (a bit more than 1 MiB, assuming 1KiB blocks)
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# for the journal
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# Note: I came to 1300 blocks after trial-and-error checks. YMMV.
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nb_blocks=$((nb_blocks+1300))
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fi
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# Add ext4 specific features
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if [ ${gen} -ge 4 ]; then
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tune2fs_O_opts+=",extents,uninit_bg,dir_index"
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fi
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# Add our -O options (there will be at most one leading comma, remove it)
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if [ -n "${tune2fs_O_opts}" ]; then
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tune2fs_opts+=( -O "${tune2fs_O_opts#,}" )
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fi
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# Add the label if specified
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if [ -n "${label}" ]; then
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tune2fs_opts+=( -L "${label}" )
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fi
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# Generate the filesystem
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genext2fs_opts=( -b ${nb_blocks} -N ${nb_inodes} -d "${root_dir}" )
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if [ -n "${nb_res_blocks}" ]; then
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genext2fs_opts+=( -m ${nb_res_blocks} )
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fi
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genext2fs "${genext2fs_opts[@]}" "${image}"
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# genext2fs does not generate a UUID, but fsck will whine if one
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# is missing, so we need to add a UUID.
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# Of course, this has to happen _before_ we run fsck.
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# Also, some ext4 metadata are based on the UUID, so we must
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# set it before we can convert the filesystem to ext4.
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# If the user did not specify a UUID, we generate a random one.
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# Although a random UUID may seem bad for reproducibility, there
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# already are so many things that are not reproducible in a
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# filesystem: file dates, file ordering, content of the files...
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tune2fs -U "${uuid:-random}" "${image}"
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# Upgrade the filesystem
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if [ ${#tune2fs_opts[@]} -ne 0 ]; then
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tune2fs "${tune2fs_opts[@]}" "${image}"
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fi
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# After changing filesystem options, running fsck is required
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# (see: man tune2fs). Running e2fsck in other cases will ensure
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# coherency of the filesystem, although it is not required.
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# 'e2fsck -pDf' means:
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# - automatically repair
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# - optimise and check for duplicate entries
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# - force checking
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# Sending output to oblivion, as e2fsck can be *very* verbose,
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# especially with filesystems generated by genext2fs.
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# Exit codes 1 & 2 are OK, it means fs errors were successfully
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# corrected, hence our little trick with $ret.
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ret=0
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e2fsck -pDf "${image}" >/dev/null || ret=$?
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case ${ret} in
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0|1|2) ;;
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*) errorN ${ret} "failed to run e2fsck on '%s' (ext%d)\n" \
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"${image}" ${gen}
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esac
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printf "\n"
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trace "e2fsck was successfully run on '%s' (ext%d)\n" "${image}" ${gen}
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printf "\n"
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# Remove count- and time-based checks, they are not welcome
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# on embedded devices, where they can cause serious boot-time
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# issues by tremendously slowing down the boot.
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tune2fs -c 0 -i 0 "${image}"
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}
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help() {
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cat <<_EOF_
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NAME
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${my_name} - Create an ext2/3/4 filesystem image
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SYNOPSIS
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${my_name} [OPTION]...
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DESCRIPTION
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Create ext2/3/4 filesystem image from the content of a directory.
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-b BLOCKS
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Create a filesystem of BLOCKS 1024-byte blocs. The default is to
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compute the required number of blocks.
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-i INODES
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Create a filesystem with INODES inodes. The default is to compute
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the required number of inodes.
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-r RES_BLOCKS
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Create a filesystem with RES_BLOCKS reserved blocks. The default
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is to reserve 0 block.
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-d ROOT_DIR
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Create a filesystem, using the content of ROOT_DIR as the content
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of the root of the filesystem. Mandatory.
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-o FILE
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Create the filesystem in FILE. Madatory.
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-G GEN -R REV
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Create a filesystem of generation GEN (2, 3 or 4), and revision
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REV (0 or 1). The default is to generate an ext2 revision 1
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filesystem; revision 0 is invalid for ext3 and ext4.
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-l LABEL
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Create a filesystem with label LABEL. The default is to not set
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a label.
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-u UUID
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Create filesystem with uuid UUID. The default is to set a random
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UUID.
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Exit status:
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0 if OK
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!0 in case of error
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_EOF_
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}
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trace() { local msg="${1}"; shift; printf "%s: ${msg}" "${my_name}" "${@}"; }
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warn() { trace "${@}" >&2; }
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errorN() { local ret="${1}"; shift; warn "${@}"; exit ${ret}; }
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error() { errorN 1 "${@}"; }
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my_name="${0##*/}"
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main "$@"
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