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7df55477fd
Introduce an extent-layer (as opposed to the existing file-level) deduplication system for btrfs. This provides a means of finding similarities within non-identical files, when they contain identical, aligned blocks.
224 lines
8.4 KiB
Bash
Executable file
224 lines
8.4 KiB
Bash
Executable file
#!@bash@/bin/bash
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PATH=@bash@/bin:@coreutils@/bin:@utillinux@/bin:@btrfsProgs@/bin:$PATH
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beesd_bin=@bees@/lib/bees/bees
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# PLEASE KEEP NIX-ISMS ABOVE THIS LINE TO EASE UPSTREAM MERGE
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#!/usr/bin/env bash
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shopt -s extglob
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# Upstream wrapper requires UUID to be used for configuration.
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# However, when declaratively describing a host, we may not know its UUID, and
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# shouldn't need to persist something that will differ between hosts built from
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# the same configuration template.
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# Thus, for using bees from NixOS, we have our own wrapper, which supports not
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# just UUID but any specification permitted by findmnt
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[[ $bees_debug ]] && { PS4=':${BASH_SOURCE##*/}:$LINENO+'; set -x; }
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usage() {
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cat >&2 <<EOF
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Usage: ${BASH_SOURCE##*/} run|cleanup config-name|fsSpec [idxSizeMB=...] [verbosity=...] [workDir=...] [-- daemon-options...]
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fsSpec should be in a format recognized by findmnt. Alternately,
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"config-name" may refer to a file that exists in ${bees_config_dir:-/etc/bees}
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with a .conf extension; if that file does not specify UUID, findmnt will be
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used in addition.
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Note that while config files may presently use shell arithmetic, use of this
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functionality is not encouraged going forward: Setting ''idxSizeMB=4096'' is
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preferred over ''DB_SIZE=$((1024*1024*1024*4))'' or ''DB_SIZE=$(( AL16M * 256 ))'',
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although both of these are presently supported.
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If fsSpec contains a /, it assumed to be a mount point to be looked up by
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findmnt, not a config file name.
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daemon-options are passed directly through to the daemon on startup, as
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documented at https://github.com/Zygo/bees/blob/master/docs/options.md.
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EOF
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exit 1
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}
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die() { echo "$*" >&2; exit 1; }
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allConfigNames=( blockdev fsSpec home idxSize idxSizeMB mntDir runDir status verbosity workDir )
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# Alternate names for configuration values; "bees_" will always be prepended
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declare -A altConfigNames=(
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# from original bees wrapper
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[BEESHOME]=home
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[BEESSTATUS]=status
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[MNT_DIR]=mntDir
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[UUID]=uuid
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[WORK_DIR]=runDir
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[DB_SIZE]=idxSize
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)
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# legacy bees config files can be arbitrary shell scripts, so we need to actually evaluate them
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sandboxedConfigFileEval() {
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bash_exe=$(type -P bash) || exit
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PATH=/var/empty ENV='' BASH_ENV='' AL128K="$((128*1024))" AL16M="$((16*1024*1024))" "$bash_exe" -r ${bees_debug+-x} \
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-c 'eval "$(</dev/stdin)" >&2; for var; do [[ ${!var} ]] && printf "%q=%s\\0" "$var" "${!var}"; done' \
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"${!altConfigNames[@]}" "${allConfigNames[@]}" \
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<"$1"
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}
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readConfigFileIfExists() {
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local line
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[[ -s $1 ]] || return 1
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while IFS= read -r -d '' line; do
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line=${line%%+([[:space:]])"#"*}
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[[ $line ]] || continue
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[[ $line = *=* ]] || {
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printf 'WARNING: Config file line not recognized: %q\n' "$line" >&2
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continue
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}
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set_option "$line"
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done < <(sandboxedConfigFileEval "$1")
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}
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set_option() {
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local k v
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k="${1%%=*}" v="${1#*=}"
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[[ ${altConfigNames[$k]} ]] && k=${altConfigNames[$k]}
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printf -v "bees_$k" %s "$v"
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}
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uuid_re='^[[:xdigit:]]{8}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{12}$'
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# Shared code for setting configuration used by other operations.
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#
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# Reads from global associative array "opts" containing options passed in as
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# key=value pairs on the command line, looks for config-file overrides, and
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# sets individual global variables.
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_setup() {
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declare fstype
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bees_fsSpec=$1; shift
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# Look for file-based configuration, additional to honoring configuration on the command line
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bees_config_dir="${bees_config_dir:-/etc/bees}"
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if [[ $bees_fsSpec =~ $uuid_re ]]; then
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bees_uuid=$bees_fsSpec
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# If our spec looks like a bare UUID, and no config file exists in the new
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# format, fall back to legacy config file search mechanism (grep; ewww).
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if ! readConfigFileIfExists "$bees_config_dir/UUID=$bees_fsSpec.conf"; then
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# Legacy approach to finding a config file: Grep for a *.conf file
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# containing the UUID within its text. Permitting spaces around the "="
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# appears to be a bug, but is retained for compatibility with the
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# original upstream script.
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allConfFiles=( "$bees_config_dir"/*.conf )
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if (( ${#allConfFiles[@]} )); then
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# in read or readarray with -d '', the NUL terminating the empty string is used as delimiter character.
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readarray -d '' -t matchingConfFiles < <(grep -E -l -Z "^[^#]*UUID[[:space:]]*=[[:space:]]*" "${allConfFiles[@]}")
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else
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matchingConfFiles=( )
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fi
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if (( ${#matchingConfFiles[@]} == 1 )); then
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# Exactly one configuration file exists in our target directory with a reference to the UUID given.
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bees_config_file=${matchingConfFiles[0]}
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readConfigFileIfExists "$bees_config_file"
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echo "NOTE: Please consider renaming $bees_config_file to $bees_config_dir/UUID=$bees_fsSpec" >&2
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echo " ...and passing UUID=$bees_fsSpec on startup." >&2
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elif (( ${#matchingConfFiles[@]} > 1 )); then
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# The legacy wrapper would silently use the first file and ignore
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# others, but... no.
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echo "ERROR: Passed a bare UUID, but multiple configuration files match it:" >&2
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printf ' - %q\n' "${matchingConfFiles[@]}" >&2
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die "Unable to continue."
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fi
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fi
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else
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# For a non-UUID fsSpec that is not a path, look only for a config file
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# exactly matching its text.
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#
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# (Passing a mount point as a fsSpec is only supported with the new
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# wrapper; all key=value pairs can be passed on the command line in this
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# mode, so config file support is not needed).
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[[ $bees_fsSpec = */* ]] || readConfigFileIfExists "$bees_config_dir/$bees_fsSpec.conf"
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fi
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[[ $bees_uuid ]] || {
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# if bees_uuid is not in our .conf file, look it up with findmnt
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read -r bees_uuid fstype < <(findmnt -n -o uuid,fstype "$bees_fsSpec") && [[ $fstype ]] || exit
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[[ $fstype = btrfs ]] || die "Device type is $fstype, not btrfs"
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}
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[[ $bees_uuid = */* ]] || readConfigFileIfExists "$bees_config_dir/UUID=$bees_uuid.conf"
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# Honor any values read from config files above; otherwise, set defaults.
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bees_workDir="${bees_workDir:-.beeshome}"
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bees_runDir="${bees_runDir:-/run/bees}"
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bees_mntDir="${bees_mntDir:-$bees_runDir/mnt/$bees_uuid}"
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bees_home="${bees_home:-$bees_mntDir/$bees_workDir}"
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bees_status="${bees_status:-${bees_runDir}/$bees_uuid.status}"
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bees_verbosity="${bees_verbosity:-6}"
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bees_idxSizeMB="${bees_idxSizeMB:-1024}"
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bees_idxSize=${bees_idxSize:-"$(( bees_idxSizeMB * 1024 * 1024 ))"}
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bees_blockdev=${bees_blockdev:-"/dev/disk/by-uuid/$bees_uuid"}
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[[ -b $bees_blockdev ]] || die "Block device $bees_blockdev missing"
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(( bees_idxSize % (16 * 1024 * 1024) == 0 )) || die "DB size must be divisible by 16MB"
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}
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do_run() {
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local db old_db_size
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_setup "$1"; shift
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mkdir -p -- "$bees_mntDir" || exit
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# subvol id 5 is reserved for the root subvolume of a btrfs filesystem.
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mountpoint -q "$bees_mntDir" || mount -osubvolid=5 -- "$bees_blockdev" "$bees_mntDir" || exit
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if [[ -d $bees_home ]]; then
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btrfs subvolume show "$bees_home" >/dev/null 2>&1 || die "$bees_home exists but is not a subvolume"
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else
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btrfs subvolume create "$bees_home" || exit
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sync # workaround for Zygo/bees#93
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fi
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db=$bees_home/beeshash.dat
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touch -- "$db"
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old_db_size=$(stat -c %s -- "$db")
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new_db_size=$bees_idxSize
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if (( old_db_size != new_db_size )); then
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rm -f -- "$bees_home"/beescrawl."$bees_uuid".dat
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truncate -s "$new_db_size" -- "$db" || exit
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fi
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chmod 700 -- "$bees_home"
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# BEESSTATUS and BEESHOME are the only variables handled by the legacy
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# wrapper for which getenv() is called in C code.
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BEESSTATUS=$bees_status BEESHOME=$bees_home exec "${beesd_bin:-/lib/bees/bees}" \
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--verbose "$bees_verbosity" \
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"$@" "$bees_mntDir" || exit
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}
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do_cleanup() {
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_setup "$1"; shift
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mountpoint -q "$bees_mntDir" && umount -l -- "$bees_mntDir" || exit
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}
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(( $# >= 2 )) || usage
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declare -f "do_$1" >/dev/null 2>&1 || usage
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mode=$1; shift # must be a do_* function; currently "run" or "cleanup"
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declare -a args=( "$1" ); shift # pass first argument (config-name|fsSpec) through literally
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# parse other arguments as key=value pairs, or pass them through literally if they do not match that form.
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# similarly, any option after "--" will be passed through literally.
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while (( $# )); do
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if [[ $1 = *=* ]]; then
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set_option "$1"
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elif [[ $1 = -- ]]; then
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shift
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args+=( "$@" )
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break
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else
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args+=( "$1" )
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fi
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shift
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done
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"do_$mode" "${args[@]}"
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