Further refactoring to emulate util-linux mount commandsemulate-util-linux-mount

Previously this script (zmount) worked like an init script, with start,
stop, status commands. Now this behaves more like the util-linux mount
commands, mount and umount. This provides the commands zmount and
zumount. Currently it only supports the `-a` switch, which mounts all or
unmounts all zram filesystems.

This also provides a makefile for installing these scripts and the
corresponding script library to their relevant directories.

5 files changed, 288 insertions, 138 deletions

diff --git a/Makefile b/Makefile
index 8a53d46..9ace0dd 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,14 @@
 .DEFAULT: install
+PREFIX := /usr
+VERSION=1.0
 
-install:
-	install -D -v -m 755 zmount       $(DESTDIR)/bin/zmount
-	install -D -v -m 755 ztab.example $(DESTDIR)/etc/ztab
+interpolate:
+	if [ ! -d tmp ]; then mkdir -p tmp; fi
+	sed 's/{{ VERSION }}/$(VERSION)/' < zmount  > tmp/zmount
+	sed 's/{{ VERSION }}/$(VERSION)/' < zumount > tmp/zumount
+
+install: interpolate
+	install -D -v -m 755 tmp/zmount        $(DESTDIR)$(PREFIX)/bin/zmount
+	install -D -v -m 755 tmp/zumount       $(DESTDIR)$(PREFIX)/bin/zumount
+	install -D -v -m 644 lib/zmount.lib.sh $(DESTDIR)$(PREFIX)/lib/zmount.lib.sh
+	install -D -v -m 755 ztab.example      $(DESTDIR)/etc/ztab
diff --git a/lib/zmount.lib.sh b/lib/zmount.lib.sh
new file mode 100644
index 0000000..5743032
--- /dev/null
+++ b/lib/zmount.lib.sh
@@ -0,0 +1,127 @@
+#!/usr/bin/env bash
+# Zmount automatically configures zram devices with the ztab config file
+# Copyright (C)  2021  Aaron Ball <nullspoon@oper.io>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+set -euo pipefail
+export IFS=$'\n\t'
+
+
+CONFIG='/etc/ztab'
+RUN='/var/run/zmount'
+
+writelog() { printf '%s\n' "${1}"; }
+error() { writelog "ERROR: ${1}" >&2; }
+
+require_root() {
+  if [ "${UID}" -ne 0 ]; then
+    printf 'Must be run as root\n' >&2
+    return 1
+  fi
+  return 0
+}
+
+zmount.ztab.parseline() {
+  local -a lineargs=()
+  lineargs=($(printf '%s\n' "${1:?}" | tr ' ' '\n'))
+  if [ "${#lineargs[@]}" -ne 5 ]; then
+    error "Line ${1} does not have correct columns"
+    return 1
+  fi
+  printf '%s\n' ${lineargs[@]}
+  return 0
+}
+
+zmount.swap.setup() {
+  local size="${1}"
+  local dev="$(zramctl -f)"
+
+  [ ! -d "${RUN}" ] && mkdir -p ${RUN}
+
+  # Check for existing mounts to avoid duplicates
+  if [ -f "${RUN}/swap" ]; then
+    error 'Zswap device already detected. Skipping duplicate.'
+    return 1
+  fi
+
+  # Create the zram device
+  zramctl "${dev}" -s "${size}" -t "$(( $(nproc) / 2 ))"
+
+  mkswap "${dev}" 2>&1 1>/dev/null
+  swapon "${dev}"
+  printf '%s\n' "${dev}" > "${RUN}/swap"
+}
+
+
+zmount.dir.setup() {
+  local fs="${1}"
+  local size="${2}"
+  local dir="${3}"
+  local opts="${4:-defaults}"
+  local perms="${5:-none}"      # Default to 777 to emulate tmpfs
+  local dev="$(zramctl -f)"
+
+  [ ! -d "${RUN}" ] && mkdir -p ${RUN}
+
+  # Check for existing mounts to avoid duplicates
+  if [ -f "${RUN}/${dir//\//_}" ]; then
+    error "Skipping duplicate mount dir ${dir}"
+    return 1
+  fi
+
+  # Create the zram device
+  zramctl "${dev}" -s "${size}" -t "$(( $(nproc) / 2 ))"
+
+  if [ "${fs}" = 'btrfs' ]; then
+    mkfs.btrfs -q "${dev}"
+  elif [ "${fs}" = 'ext2' ]; then
+    mkfs.ext2 -q "${dev}"
+  elif [ "${fs}" = 'ext3' ]; then
+    mkfs.ext3 -q "${dev}"
+  elif [ "${fs}" = 'ext4' ]; then
+    mkfs.ext4 -q "${dev}"
+  elif [ "${fs}" = 'exfat' ]; then
+    mkfs.exfat -q "${dev}"
+  elif [ "${fs}" = 'vfat' ]; then
+    mkfs.vfat -q "${dev}"
+  elif [ "${fs}" = 'xfs' ]; then
+    mkfs.xfs -q "${dev}"
+  else
+    printf 'Unknown filesystem type %s\n' "${fs}"
+    return 1
+  fi
+  mount -o "${opts}" "${dev}" "${dir}"
+  printf '%s\n' "${dev}" > "${RUN}/${dir//\//_}"
+}
+
+zmount.dir.setperms() {
+  local dir="${1}"
+  local permstr="${2}"
+  local perm
+  local -a keyval=()
+
+  [ "${permstr}" = 'none' ] && return 0
+
+  for perm in $(printf '%s\n' ${permstr} | tr ',' '\n'); do
+    keyval=($(printf '%s\n' "${perm}" | tr '=' '\n'))
+    if [ "${keyval[0]}" = 'user' ]; then
+      chown "${keyval[1]}" "${dir}"
+    elif [ "${keyval[0]}" = 'group' ]; then
+      chgrp "${keyval[1]}" "${dir}"
+    elif [ "${keyval[0]}" = 'mode' ]; then
+      chmod "${keyval[1]}" "${dir}"
+    fi
+  done
+}
diff --git a/zmount b/zmount
index 42721f7..c12e73b 100755
--- a/zmount
+++ b/zmount
@@ -18,161 +18,67 @@
 set -euo pipefail
 export IFS=$'\n\t'
 
-CONFIG='/etc/ztab'
-RUN='/var/run/zmount'
-
-_parseline() {
-  local -a lineargs=()
-  lineargs=($(printf '%s\n' "${1:?}" | tr ' ' '\n'))
-  if [ "${#lineargs[@]}" -ne 5 ]; then
-    printf 'ERROR: Line "%s" does not have correct columns\n' >&2
-    return 1
-  fi
-  printf '%s\n' ${lineargs[@]}
-  return 0
-}
-
-_setperms() {
-  local dir="${1}"
-  local permstr="${2}"
-  local perm
-  local -a keyval=()
-
-  [ "${permstr}" = 'none' ] && return 0
-
-  for perm in $(printf '%s\n' ${permstr} | tr ',' '\n'); do
-    keyval=($(printf '%s\n' "${perm}" | tr '=' '\n'))
-    if [ "${keyval[0]}" = 'user' ]; then
-      chown "${keyval[1]}" "${dir}"
-    elif [ "${keyval[0]}" = 'group' ]; then
-      chgrp "${keyval[1]}" "${dir}"
-    elif [ "${keyval[0]}" = 'mode' ]; then
-      chmod "${keyval[1]}" "${dir}"
-    fi
-  done
-}
-
-_setup_dev() {
-  local fs="${1}"
-  local size="${2}"
-  local dir="${3}"
-  local opts="${4:-defaults}"
-  local perms="${5:-none}"      # Default to 777 to emulate tmpfs
-
-  local dev="$(zramctl -f)"
-  local threads="$(( $(nproc) / 2 ))"
-
-  [ ! -d "${RUN}" ] && mkdir -p ${RUN}
-
-  # Check for existing mounts to avoid duplicates
-  if [ "${fs}" = 'swap' ] && [ -f "${RUN}/swap" ]; then
-    printf 'ERROR: Zswap device already detected. Skipping second.\n' >&2
-    return 1
-  elif [ -f "${RUN}/${dir//\//_}" ]; then
-    printf 'ERROR: Skipping duplicate mount dir %s\n' "${dir}" >&2
-    return 1
-  fi
-
-  # Create the zram device
-  zramctl "${dev}" -s "${size}" -t "${threads}"
-
-  if [ "${fs}" = 'swap' ]; then
-    mkswap "${dev}" 2>&1 1>/dev/null
-    swapon "${dev}"
-    printf '%s\n' "${dev}" > "${RUN}/swap"
-  else
-    if [ "${fs}" = 'btrfs' ]; then
-      mkfs.btrfs -q "${dev}"
-    elif [ "${fs}" = 'ext2' ]; then
-      mkfs.ext2 -q "${dev}"
-    elif [ "${fs}" = 'ext3' ]; then
-      mkfs.ext3 -q "${dev}"
-    elif [ "${fs}" = 'ext4' ]; then
-      mkfs.ext4 -q "${dev}"
-    elif [ "${fs}" = 'exfat' ]; then
-      mkfs.exfat -q "${dev}"
-    elif [ "${fs}" = 'vfat' ]; then
-      mkfs.vfat -q "${dev}"
-    elif [ "${fs}" = 'xfs' ]; then
-      mkfs.xfs -q "${dev}"
-    else
-      printf 'Unknown filesystem type %s\n' "${fs}"
-      return 1
-    fi
-    mount -o "${opts}" "${dev}" "${dir}"
-    printf '%s\n' "${dev}" > "${RUN}/${dir//\//_}"
-  fi
-}
+LIBDIR="${LIBDIR:-/usr/lib}"
+source "${LIBDIR}/zmount.lib.sh"
 
 status() { zramctl; }
 
-start() {
+mountall() {
   local -a lineargs=()
 
-  for line in $(grep -v '^#' /etc/ztab); do
-    lineargs=($(_parseline "${line}"))
+  for line in $(grep -v '^ *#\|^$' "${CONFIG}"); do
+    lineargs=($(zmount.ztab.parseline "${line}"))
 
     if [ "${lineargs[0]}" = 'swap' ]; then
-      printf 'Setting up %s zswap\n' "${lineargs[1]}"
+      writelog "Setting up ${lineargs[1]} zswap"
+      zmount.swap.setup ${lineargs[1]} || continue
     else
-      printf 'Setting up %s zram dev on %s\n' "${lineargs[1]}" "${lineargs[2]}"
+      writelog "Setting up ${lineargs[1]} zram dev on ${lineargs[2]}"
+      zmount.dir.setup ${lineargs[@]} || continue
+      zmount.dir.setperms "${lineargs[2]}" "${lineargs[4]}"
     fi
-    _setup_dev ${lineargs[@]}
-    _setperms "${lineargs[2]}" "${lineargs[4]}"
   done
 }
 
+gethelp() {
+  cat - <<EOF
 
-stop() {
-  local -a lineargs=()
-  local fs size dir
-
-  for line in $(grep -v '^#' /etc/ztab); do
-    lineargs=($(_parseline "${line}"))
-    fs="${lineargs[0]}"
-    size="${lineargs[1]}"
-    dir="${lineargs[2]}"
-    # Ignore opts and perms column
-
-    if [ "${fs}" = 'swap' ] && [ -f "${RUN}/swap" ]; then
-      dev="$(cat ${RUN}/swap)"
-      printf 'Stopping %s (mounted as swap)\n' "${dev}"
-      swapoff "${dev}"
-      rm -f "${RUN}/swap"
-    else
-      if [ ! -f "${RUN}/${dir//\//_}" ]; then
-        printf '%s is already unmounted from %s\n' "${fs}" "${dir}"
-        continue
-      fi
-      dev="$(cat ${RUN}/${dir//\//_})"
-      printf 'Stopping %s (mounted on %s)\n' "${dev}" "${dir}"
-      umount "${dir}" || :   # Ignore unmount failures
-      rm -f "${RUN}/${dir//\//_}"
-    fi
-    zramctl "${dev}" -r
-  done
-}
+Usage:
+  zmount [-hV]
+  zmount -a
+  zmount <path>
 
+Mount zram filesystems.
+
+Options:
+  -a, --all               unmount all zram filesystems
+
+  -h, --help              display this help
+  -V, --version           display version
+
+EOF
+}
 
 main() {
-  if [ ${UID} -ne 0 ]; then
-    printf 'Must be run as root\n' >&2
-    return 1
-  fi
+  local -a args=(${@})
 
   # Make sure the zram module is loaded
   modprobe zram
 
-  if [ "${1:-}" = 'start' ]; then
-    start
-  elif [ "${1:-}" = 'stop' ]; then
-    stop
-  elif [ "${1:-}" = 'status' ]; then
-    status
-  else
-    printf 'usage: %s [start|stop|status]\n' "${0}"
-    return 1
-  fi
+  # Print status if no args specified
+  [ "${#args[@]}" -eq 0 ] && status && return 0
+
+  for arg in ${args[@]}; do
+    if [ "${arg}" = '-h' ] || [ "${arg}" = '--help' ]; then
+      gethelp
+    elif [ "${arg}" = '-V' ] || [ "${arg}" = '--version' ]; then
+      writelog 'zmount {{ VERSION }}'
+    else
+      if [ "${arg}" = '-a' ]; then
+        require_root && mountall
+      fi
+    fi
+  done
 }
 
 main ${@}
diff --git a/zmount.init b/zmount.init
new file mode 100755
index 0000000..99972f1
--- /dev/null
+++ b/zmount.init
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+set -euo pipefail
+export IFS=$'\n\t'
+
+if [ "${1}" = 'start' ]; then
+  zmount -a
+elif [ "${1}" = 'stop' ]; then
+  zumount -a
+elif [ "${1}" = 'status' ]; then
+  zmount
+fi
diff --git a/zumount b/zumount
new file mode 100755
index 0000000..08ad6c5
--- /dev/null
+++ b/zumount
@@ -0,0 +1,97 @@
+#!/usr/bin/env bash
+# Zmount automatically configures zram devices with the ztab config file
+# Copyright (C)  2021  Aaron Ball <nullspoon@oper.io>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+set -euo pipefail
+export IFS=$'\n\t'
+
+LIBDIR="${LIBDIR:-/usr/lib}"
+source "${LIBDIR}/zmount.lib.sh"
+
+umountall() {
+  local -a lineargs=()
+  local fs size dir
+
+  for line in $(grep -v '^#' "${CONFIG}"); do
+    lineargs=($(zmount.ztab.parseline "${line}"))
+    fs="${lineargs[0]}"
+    size="${lineargs[1]}"
+    dir="${lineargs[2]}"
+    # Ignore opts and perms column
+
+    if [ "${fs}" = 'swap' ] && [ -f "${RUN}/swap" ]; then
+      dev="$(cat ${RUN}/swap)"
+      writelog "Stopping ${dev} (mounted as swap)"
+      swapoff "${dev}"
+      rm -f "${RUN}/swap"
+    else
+      if [ ! -f "${RUN}/${dir//\//_}" ]; then
+        writelog "${fs} is already unmounted from ${dir}"
+        continue
+      fi
+      dev="$(cat ${RUN}/${dir//\//_})"
+      writelog "Stopping ${dev} (mounted on ${dir})"
+      umount "${dir}" || :   # Ignore unmount failures
+      rm -f "${RUN}/${dir//\//_}"
+    fi
+    zramctl "${dev}" -r
+  done
+}
+
+gethelp() {
+  cat - <<EOF
+
+Usage:
+  zumount [-hV]
+  zumount -a
+  zumount <path>
+
+Unmount zram filesystems.
+
+Options:
+  -a, --all               unmount all zram filesystems
+
+  -h, --help              display this help
+  -V, --version           display version
+
+EOF
+}
+
+
+main() {
+  local -a args=(${@})
+
+  # Print status if no args specified
+  if [ "${#args[@]}" -eq 0 ]; then
+    printf 'zumount: bad usage\n' >&2
+    printf "Try 'zumount --help' for more information.\n" >&2
+    return 1
+  fi
+
+  for arg in ${args[@]}; do
+    if [ "${arg}" = '-h' ] || [ "${arg}" = '--help' ]; then
+      gethelp
+    elif [ "${arg}" = '-V' ] || [ "${arg}" = '--version' ]; then
+      writelog 'zumount {{ VERSION }}'
+    else
+      if [ "${arg}" = '-a' ]; then
+        require_root && umountall
+      fi
+    fi
+  done
+}
+
+main ${@}