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LetMeSOThat4U
Asked: 2018-11-17 03:51:44 +0800 CST

Getting info about a weird directory

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Joplin desktop app (https://joplin.cozic.net/) creates a directory in /tmp that I cannot get any info about as root:

While logged in as a regular user I can enter a dir, I cannot even display its attributes:

regularuser@homehost /tmp % ls -ld .mount_JoplinHNsadS
drwxrwxr-x 4 root root 0 Sep 30 21:48 .mount_JoplinHNsadS

regularuser@homehost /tmp % lsattr .mount_JoplinHNsadS
lsattr: Function not implemented While reading flags on .mount_JoplinHNsadS/AppRun
lsattr: Inappropriate ioctl for device While reading flags on .mount_JoplinHNsadS/app
lsattr: Function not implemented While reading flags on .mount_JoplinHNsadS/joplin.desktop
lsattr: Operation not supported While reading flags on .mount_JoplinHNsadS/joplin.png
lsattr: Inappropriate ioctl for device While reading flags on .mount_JoplinHNsadS/usr

However, root cannot even enter this directory:

root@homehost /tmp % ls -al | grep mount
ls: cannot access '.mount_JoplinHNsadS': Permission denied
d?????????  ? ?    ?         ?            ? .mount_JoplinHNsadS

root@homehost /tmp % file .mount_JoplinHNsadS
.mount_JoplinHNsadS: cannot open `.mount_JoplinHNsadS' (Permission denied)

Why is that happening? I thought root can access any directory, even with sticky bit set like /tmp?

How to diagnose such a directory as root? How was this directory created?

linux

1 Answers

  1. Thanks to Michael Hampton:

    % mount | fgrep .mount
Joplin-1.0.111-x86_64.AppImage on /tmp/.mount_JoplinHNsadS type fuse.Joplin-1.0.111-x86_64.AppImage (ro,nosuid,nodev,relatime,user_id=1000,group_id=1000)
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