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Introduce service wrapper permitting less stateful configuration #104

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320 changes: 196 additions & 124 deletions scripts/beesd.in
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Original file line number Diff line number Diff line change
@@ -1,146 +1,218 @@
#!/bin/bash
#!/usr/bin/env bash
bees_config_dir=@ETC_PREFIX@/bees/
bees_bin=$(realpath @LIBEXEC_PREFIX@/bees)
readonly bees_config_dir bees_bin

## Helpful functions
INFO(){ echo "INFO:" "$@"; }
ERRO(){ echo "ERROR:" "$@"; exit 1; }
YN(){ [[ "$1" =~ (1|Y|y) ]]; }
shopt -s extglob

## Global vars
export BEESHOME BEESSTATUS
export WORK_DIR CONFIG_DIR
export CONFIG_FILE
export UUID AL16M AL128K
# Prior wrapper required UUID to be used for configuration. Current one permits
# this legacy mode, but also permits reference to named configuration files, or
# `findmnt`-compatible mount point specifications with other arguments passed
# key/value style.

readonly AL128K="$((128*1024))"
readonly AL16M="$((16*1024*1024))"
readonly CONFIG_DIR=@ETC_PREFIX@/bees/
[[ $bees_debug ]] && { PS4=':${BASH_SOURCE##*/}:$LINENO+'; set -x; }

readonly bees_bin=$(realpath @LIBEXEC_PREFIX@/bees)
usage() {
cat >&2 <<EOF
Usage: ${BASH_SOURCE##*/} run|cleanup config-name|fsSpec [idxSizeMB=...] [verbosity=...] [workDir=...] [-- daemon-options...]

command -v "$bees_bin" &> /dev/null || ERRO "Missing 'bees' agent"
fsSpec should be in a format recognized by findmnt. Alternately,
"config-name" may refer to a file that exists in ${bees_config_dir:-/etc/bees}
with a .conf extension; if that file does not specify UUID, findmnt will be
used in addition.

uuid_valid(){
if uuidparse -n -o VARIANT $1 | grep -i -q invalid; then
false
fi
}
Note that while config files may presently use shell arithmetic, use of this
functionality is not encouraged going forward: Setting ''idxSizeMB=4096'' is
preferred over ''DB_SIZE=$((1024*1024*1024*4))'' or ''DB_SIZE=$(( AL16M * 256 ))'',
although both of these are presently supported.

help(){
echo "Usage: beesd [options] <btrfs_uuid>"
echo "- - -"
exec "$bees_bin" --help
}
If fsSpec contains a /, it assumed to be a mount point to be looked up by
findmnt, not a config file name.

get_bees_supp_opts(){
"$bees_bin" --help |& awk '/--../ { gsub( ",", "" ); print $1 " " $2}'
daemon-options are passed directly through to the daemon on startup, as
documented at https://github.com/Zygo/bees/blob/master/docs/options.md.
EOF
exit 1
}

SUPPORTED_ARGS=(
$(get_bees_supp_opts)
)
NOT_SUPPORTED_ARGS=()
ARGUMENTS=()

for arg in "${@}"; do
supp=false
for supp_arg in "${SUPPORTED_ARGS[@]}"; do
if [ "$arg" == "$supp_arg" ]; then
supp=true
break
fi
done
if $supp; then
ARGUMENTS+=($arg)
else
NOT_SUPPORTED_ARGS+=($arg)
fi
done

for arg in "${ARGUMENTS[@]}"; do
case $arg in
-h) help;;
--help) help;;
esac
done

for arg in "${NOT_SUPPORTED_ARGS[@]}"; do
if uuid_valid $arg; then
[ ! -z "$UUID" ] && help
UUID=$arg
fi
done
die() { echo "$*" >&2; exit 1; }

[ -z "$UUID" ] && help


FILE_CONFIG="$(egrep -l '^[^#]*UUID\s*=\s*"?'"$UUID" "$CONFIG_DIR"/*.conf | head -1)"
[ ! -f "$FILE_CONFIG" ] && ERRO "No config for $UUID"
INFO "Find $UUID in $FILE_CONFIG, use as conf"
source "$FILE_CONFIG"
allConfigNames=( blockdev fsSpec home idxSize idxSizeMB mntDir runDir status verbosity workDir )

# Alternate names for configuration values; "bees_" will always be prepended
declare -A altConfigNames=(
# from original bees wrapper
[BEESHOME]=home
[BEESSTATUS]=status
[MNT_DIR]=mntDir
[UUID]=uuid
[WORK_DIR]=runDir
[DB_SIZE]=idxSize
)

## Pre checks
{
[ ! -d "$CONFIG_DIR" ] && ERRO "Missing: $CONFIG_DIR"
[ "$UID" == "0" ] || ERRO "Must be run as root"
# legacy bees config files can be arbitrary shell scripts, so we need to actually evaluate them
sandboxedConfigFileEval() {
bash_exe=$(type -P bash) || exit
PATH=/var/empty ENV='' BASH_ENV='' AL128K="$((128*1024))" AL16M="$((16*1024*1024))" "$bash_exe" -r ${bees_debug+-x} \
-c 'eval "$(</dev/stdin)" >&2; for var; do [[ ${!var} ]] && printf "%q=%s\\0" "$var" "${!var}"; done' \
"${!altConfigNames[@]}" "${allConfigNames[@]}" \
<"$1"
}

readConfigFileIfExists() {
local line
[[ -s $1 ]] || return 1
while IFS= read -r -d '' line; do
line=${line%%+([[:space:]])"#"*}
[[ $line ]] || continue
[[ $line = *=* ]] || {
printf 'WARNING: Config file line not recognized: %q\n' "$line" >&2
continue
}
set_option "$line"
done < <(sandboxedConfigFileEval "$1")
}

WORK_DIR="${WORK_DIR:-/run/bees/}"
MNT_DIR="${MNT_DIR:-$WORK_DIR/mnt/$UUID}"
BEESHOME="${BEESHOME:-$MNT_DIR/.beeshome}"
BEESSTATUS="${BEESSTATUS:-$WORK_DIR/$UUID.status}"
DB_SIZE="${DB_SIZE:-$((8192*AL128K))}"

INFO "Check: Disk exists"
if [ ! -b "/dev/disk/by-uuid/$UUID" ]; then
ERRO "Missing disk: /dev/disk/by-uuid/$UUID"
fi

is_btrfs(){ [ "$(blkid -s TYPE -o value "$1")" == "btrfs" ]; }

INFO "Check: Disk with btrfs"
if ! is_btrfs "/dev/disk/by-uuid/$UUID"; then
ERRO "Disk not contain btrfs: /dev/disk/by-uuid/$UUID"
fi

INFO "WORK DIR: $WORK_DIR"
mkdir -p "$WORK_DIR" || exit 1

INFO "MOUNT DIR: $MNT_DIR"
mkdir -p "$MNT_DIR" || exit 1

umount_w(){ mountpoint -q "$1" && umount -l "$1"; }
force_umount(){ umount_w "$MNT_DIR"; }
trap force_umount SIGINT SIGTERM EXIT
set_option() {
local k v
k="${1%%=*}" v="${1#*=}"
[[ ${altConfigNames[$k]} ]] && k=${altConfigNames[$k]}
printf -v "bees_$k" %s "$v"
}

mount -osubvolid=5 /dev/disk/by-uuid/$UUID "$MNT_DIR" || exit 1
uuid_re='^[[:xdigit:]]{8}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{12}$'

# Shared code for setting configuration used by other operations.
#
# Reads from global associative array "opts" containing options passed in as
# key=value pairs on the command line, looks for config-file overrides, and
# sets individual global variables.
_setup() {
declare fstype
bees_fsSpec=$1; shift

# Look for file-based configuration, additional to honoring configuration on the command line
bees_config_dir="${bees_config_dir:-/etc/bees}"
if [[ $bees_fsSpec =~ $uuid_re ]]; then
bees_uuid=$bees_fsSpec
# If our spec looks like a bare UUID, and no config file exists in the new
# format, fall back to legacy config file search mechanism (grep; ewww).
if ! readConfigFileIfExists "$bees_config_dir/UUID=$bees_fsSpec.conf"; then
# Legacy approach to finding a config file: Grep for a *.conf file
# containing the UUID within its text. Permitting spaces around the "="
# appears to be a bug, but is retained for compatibility with the
# original upstream script.
allConfFiles=( "$bees_config_dir"/*.conf )
if (( ${#allConfFiles[@]} )); then
# in read or readarray with -d '', the NUL terminating the empty string is used as delimiter character.
readarray -d '' -t matchingConfFiles < <(grep -E -l -Z "^[^#]*UUID[[:space:]]*=[[:space:]]*" "${allConfFiles[@]}")
else
matchingConfFiles=( )
fi
if (( ${#matchingConfFiles[@]} == 1 )); then
# Exactly one configuration file exists in our target directory with a reference to the UUID given.
bees_config_file=${matchingConfFiles[0]}
readConfigFileIfExists "$bees_config_file"
echo "NOTE: Please consider renaming $bees_config_file to $bees_config_dir/UUID=$bees_fsSpec" >&2
echo " ...and passing UUID=$bees_fsSpec on startup." >&2
elif (( ${#matchingConfFiles[@]} > 1 )); then
# The legacy wrapper would silently use the first file and ignore
# others, but... no.
echo "ERROR: Passed a bare UUID, but multiple configuration files match it:" >&2
printf ' - %q\n' "${matchingConfFiles[@]}" >&2
die "Unable to continue."
fi
fi
else
# For a non-UUID fsSpec that is not a path, look only for a config file
# exactly matching its text.
#
# (Passing a mount point as a fsSpec is only supported with the new
# wrapper; all key=value pairs can be passed on the command line in this
# mode, so config file support is not needed).
[[ $bees_fsSpec = */* ]] || readConfigFileIfExists "$bees_config_dir/$bees_fsSpec.conf"
fi

[[ $bees_uuid ]] || {
# if bees_uuid is not in our .conf file, look it up with findmnt
read -r bees_uuid fstype < <(findmnt -n -o uuid,fstype "$bees_fsSpec") && [[ $fstype ]] || exit
[[ $fstype = btrfs ]] || die "Device type is $fstype, not btrfs"
}

[[ $bees_uuid = */* ]] || readConfigFileIfExists "$bees_config_dir/UUID=$bees_uuid.conf"

# Honor any values read from config files above; otherwise, set defaults.
bees_workDir="${bees_workDir:-.beeshome}"
bees_runDir="${bees_runDir:-/run/bees}"
bees_mntDir="${bees_mntDir:-$bees_runDir/mnt/$bees_uuid}"
bees_home="${bees_home:-$bees_mntDir/$bees_workDir}"
bees_status="${bees_status:-${bees_runDir}/$bees_uuid.status}"
bees_verbosity="${bees_verbosity:-6}"
bees_idxSizeMB="${bees_idxSizeMB:-1024}"
bees_idxSize=${bees_idxSize:-"$(( bees_idxSizeMB * 1024 * 1024 ))"}
bees_blockdev=${bees_blockdev:-"/dev/disk/by-uuid/$bees_uuid"}

[[ -b $bees_blockdev ]] || die "Block device $bees_blockdev missing"
(( bees_idxSize % (128 * 1024) == 0 )) || die "DB size must be divisible by 128KB"
}

if [ ! -d "$BEESHOME" ]; then
INFO "Create subvol $BEESHOME for store bees data"
btrfs sub cre "$BEESHOME"
else
btrfs sub show "$BEESHOME" &> /dev/null || ERRO "$BEESHOME MUST BE A SUBVOL!"
fi
do_run() {
local db old_db_size

_setup "$1"; shift
mkdir -p -- "$bees_mntDir" || exit

# subvol id 5 is reserved for the root subvolume of a btrfs filesystem.
mountpoint -q "$bees_mntDir" || mount -osubvolid=5 -- "$bees_blockdev" "$bees_mntDir" || exit
if [[ -d $bees_home ]]; then
btrfs subvolume show "$bees_home" >/dev/null 2>&1 || die "$bees_home exists but is not a subvolume"
else
btrfs subvolume create "$bees_home" || exit
sync # workaround for Zygo/bees#93
fi
db=$bees_home/beeshash.dat
touch -- "$db"

old_db_size=$(stat -c %s -- "$db")
new_db_size=$bees_idxSize

if (( old_db_size != new_db_size )); then
rm -f -- "$bees_home"/beescrawl."$bees_uuid".dat
truncate -s "$new_db_size" -- "$db" || exit
fi
chmod 700 -- "$bees_home"

# BEESSTATUS and BEESHOME are the only variables handled by the legacy
# wrapper for which getenv() is called in C code.
BEESSTATUS=$bees_status BEESHOME=$bees_home exec "${beesd_bin:-/lib/bees/bees}" \
--verbose "$bees_verbosity" \
"$@" "$bees_mntDir" || exit
}

# Check DB size
{
DB_PATH="$BEESHOME/beeshash.dat"
touch "$DB_PATH"
OLD_SIZE="$(du -b "$DB_PATH" | sed 's/\t/ /g' | cut -d' ' -f1)"
NEW_SIZE="$DB_SIZE"
if (( "$NEW_SIZE"%AL128K > 0 )); then
ERRO "DB_SIZE Must be multiple of 128K"
fi
if (( "$OLD_SIZE" != "$NEW_SIZE" )); then
INFO "Resize db: $OLD_SIZE -> $NEW_SIZE"
[ -f "$BEESHOME/beescrawl.$UUID.dat" ] && rm "$BEESHOME/beescrawl.$UUID.dat"
truncate -s $NEW_SIZE $DB_PATH
fi
chmod 700 "$DB_PATH"
do_cleanup() {
_setup "$1"; shift
mountpoint -q "$bees_mntDir" && umount -l -- "$bees_mntDir" || exit
}

MNT_DIR="$(realpath $MNT_DIR)"
(( $# >= 2 )) || usage
declare -f "do_$1" >/dev/null 2>&1 || usage
mode=$1; shift # must be a do_* function; currently "run" or "cleanup"

declare -a args=( "$1" ); shift # pass first argument (config-name|fsSpec) through literally

# parse other arguments as key=value pairs, or pass them through literally if they do not match that form.
# similarly, any option after "--" will be passed through literally.
while (( $# )); do
if [[ $1 = *=* ]]; then
set_option "$1"
elif [[ $1 = -- ]]; then
shift
args+=( "$@" )
break
else
args+=( "$1" )
fi
shift
done

cd "$MNT_DIR"
"$bees_bin" "${ARGUMENTS[@]}" $OPTIONS "$MNT_DIR"
"do_$mode" "${args[@]}"