在appimage内部使用unionfs

Question

我正在从AppImage(使用AppImage -builder v0.9.2创建)中的脚本创建一个覆盖FS(使用unionfs-fuse)。
覆盖被成功挂载，但是在脚本的最后，它无法正确地卸载'Operation not permitted'。
AppImage结束后，fusermount -u工作正常。

下面是脚本script.sh:

#!/bin/sh
ROOT_DIR=$(mktemp -d -t test-XXXXXX)
myUID=$(id -u)
myGID=$(id -g)
USER_DIR=/tmp/a
mkdir -p ${USER_DIR}
echo "Hello world!" > ${USER_DIR}/hello.txt
# create an overlay of $USER_DIR (rw) over $APPDIR (ro) into $ROOT_DIR
UNIONFS="unionfs -o cow,uid=${myUID},gid=${myGID} ${USER_DIR}=RW:${APPDIR} ${ROOT_DIR}"
if ! $( ${UNIONFS} ); then
echo "mount failed!"
exit 1
fi
echo "overlay created in ${ROOT_DIR}"
# files in $USER_DIR may be read/written from the overlay
cat ${ROOT_DIR}/hello.txt
# unmount overlay before closing the AppImage
fusermount -zu ${ROOT_DIR}
rmdir ${ROOT_DIR}

这是AppImage配方AppImageBuilder.yml:

version: 1
AppDir:
path: /home/user/bugreport
app_info:
id: org.appimage.test
name: AppimageTest
icon: terminal
version: 0.0.1
exec: bin/dash
exec_args: "script.sh"
apt:
arch: amd64
sources:
- sourceline: 'deb [arch=amd64] http://archive.ubuntu.com/ubuntu/ bionic main restricted universe multiverse'
key_url: 'http://keyserver.ubuntu.com/pks/lookup?op=get&search=0x3b4fe6acc0b21f32'
- sourceline: 'deb [arch=amd64] http://archive.ubuntu.com/ubuntu/ bionic-updates main restricted universe multiverse'
- sourceline: 'deb [arch=amd64] http://archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse'
include: [unionfs-fuse, dash, coreutils]
exclude: []
AppImage:
arch: x86_64
update-information: None
sign-key: None

(terminal.png中也需要一个随机图标文件来构建AppImage)。

AppImage使用:

$ appimage-builder --recipe ./AppImageBuilder.yml

任何帮助将不胜感激!

Answer 1

变通办法是:

• 使用auto_unmount选项启动unionfs
• 代替fusermount -u，用pkill -nf ${ROOT_DIR}杀死最后一个unionfs进程
  (杀死最近一个参数中有${ROOT_DIR}的进程)

生成的脚本:

#!/bin/sh
ROOT_DIR=$(mktemp -d -t test-XXXXXX)
myUID=$(id -u)
myGID=$(id -g)
USER_DIR=/tmp/a
mkdir -p ${USER_DIR}
echo "Hello world!" > ${USER_DIR}/hello.txt
# create an overlay of $USER_DIR (rw) over $APPDIR (ro) into $ROOT_DIR
UNIONFS="unionfs -o cow,auto_unmount,uid=${myUID},gid=${myGID} ${USER_DIR}=RW:${APPDIR} ${ROOT_DIR}"
if ! $( ${UNIONFS} ); then
echo "mount failed!"
exit 1
fi
echo "overlay created in ${ROOT_DIR}"
# files in $USER_DIR may be read/written from the overlay
cat ${ROOT_DIR}/hello.txt
# killing unionfs will unmount the overlay
pkill -nf ${ROOT_DIR}
sleep 0.1
rmdir ${ROOT_DIR}