Ubuntu 22.04下Ubuntu Software与LibreOffice 7.5无法启动问题求助

我的Ubuntu 22.04系统之前一切正常，关机几天后再启动，发现LibreOffice 7.5和Ubuntu Software都打不开了，完全摸不着头脑，有没有大佬能给点排查思路或者解决办法？

按照@waltinator的建议，我运行了journalctl --since="-5 minutes"命令，截取了尝试启动Ubuntu Software前后的日志片段：

Jul 19 12:20:35 tim-*** systemd[2844]: snap.snapd-desktop-integration.snapd-desktop-integration.service: Scheduled restart job, restart counter is at 1811.

Jul 19 12:20:35 tim-*** systemd[2844]: Stopped Service for snap application snapd-desktop-integration.snapd-desktop-integration.

Jul 19 12:20:35 tim-*** systemd[2844]: Started Service for snap application snapd-desktop-integration.snapd-desktop-integration.

Jul 19 12:20:35 tim-*** snapd-desktop-i[296916]: Failed to do gtk init. Waiting for a new session with desktop capabilities.

Jul 19 12:20:35 tim-*** snapd-desktop-i[296916]: Checking session /org/freedesktop/login1/session/_33...

Jul 19 12:20:35 tim-*** snapd-desktop-i[296916]: Is a desktop session! Forcing a reload.

Jul 19 12:20:35 tim-*** snapd-desktop-i[296916]: Loop exited. Forcing reload.

Jul 19 12:20:37 tim-*** systemd[2844]: Started Application launched by gnome-shell.

Jul 19 12:20:37 tim-*** systemd[2844]: Started snap.snap-store.ubuntu-software.feff5749-f19c-4c6e-987d-f9ac7307a9b2.scope.

Jul 19 12:20:37 tim-*** audit[296920]: AVC apparmor="DENIED" operation="open" class="file" profile="snap.snap-store.ubuntu-software" name="/etc/xdg/mimeapps.list" pid=296920 comm="snap-store" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0

Jul 19 12:20:37 tim-*** kernel: audit: type=1400 audit(1689787237.299:670): apparmor="DENIED" operation="open" class="file" profile="snap.snap-store.ubuntu-software" name="/etc/xdg/mimeapps.list" pid=296920 comm="snap-store" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0

Jul 19 12:20:37 tim-*** snap-store[296920]: cannot open display: :0

Jul 19 12:20:38 tim-*** systemd[2844]: snap.snapd-desktop-integration.snapd-desktop-integration.service: Scheduled restart job, restart counter is at 1812.

Jul 19 12:20:38 tim-*** systemd[2844]: Stopped Service for snap application snapd-desktop-integration.snapd-desktop-integration.

Jul 19 12:20:38 tim-*** systemd[2844]: Started Service for snap application snapd-desktop-integration.snapd-desktop-integration.

Jul 19 12:20:38 tim-*** snapd-desktop-i[297103]: Failed to do gtk init. Waiting for a new session with desktop capabilities.

Jul 19 12:20:38 tim-*** snapd-desktop-i[297103]: Checking session /org/freedesktop/login1/session/_33...

Jul 19 12:20:38 tim-*** snapd-desktop-i[297103]: Is a desktop session! Forcing a reload.

Jul 19 12:20:38 tim-*** snapd-desktop-i[297103]: Loop exited. Forcing reload.

问题排查与解决建议 #

从你贴的日志里，我发现几个关键异常点，应该是导致应用启动失败的核心原因：

1. AppArmor权限拦截：Ubuntu Software（snap版）尝试读取/etc/xdg/mimeapps.list文件时被权限拒绝，这会直接影响应用的初始化流程
2. 显示会话连接失败：cannot open display: :0说明程序无法连接到当前的桌面显示会话，大概率是环境变量或权限配置出了问题
3. snap桌面集成服务循环重启：snapd-desktop-integration服务一直在反复重启，这个服务负责snap应用与桌面环境的交互，它异常会直接拖垮依赖它的应用

给你几个可以一步步尝试的解决办法：

1. 修复mimeapps.list文件权限

先查看这个文件的权限是否正常：

ls -l /etc/xdg/mimeapps.list

正常情况下，所有者为root，权限应为-rw-r--r--（对应数值644）。如果权限异常，执行以下命令重置：

sudo chmod 644 /etc/xdg/mimeapps.list

2. 重启snap相关服务

很多时候服务异常重启就能解决问题，先重启snapd主服务和桌面集成服务：

sudo systemctl restart snapd.service
systemctl --user restart snapd-desktop-integration.service

重启完成后，尝试打开Ubuntu Software和LibreOffice

3. 重置snap应用的权限配置

针对snap版应用，可以用--amend参数刷新配置，重置其AppArmor权限规则：

# 重置Ubuntu Software
sudo snap refresh snap-store --amend

# 如果LibreOffice是snap版，同样执行重置
sudo snap refresh libreoffice --amend

4. 检查并设置显示环境变量

有时候会话的DISPLAY变量会出现异常，先在终端里确认当前变量值：

echo $DISPLAY

正常应输出:0，如果不是，手动设置后再启动应用：

export DISPLAY=:0
snap-store &
libreoffice &

5. 最后一招：重装应用

如果上面的方法都无效，那就卸载重装这两个应用试试：

# 卸载并重装Ubuntu Software
sudo snap remove snap-store
sudo snap install snap-store

# 卸载并重装LibreOffice（snap版）
sudo snap remove libreoffice
sudo snap install libreoffice

备注：内容来源于stack exchange，提问作者BeFreeIL