MacOS – Deleted symlink to /etc and now missing sudoers

macossudo

I messed up bad, real bad.

I accidentally deleted the symbolic link to my /etc directory. Now I can't create another one because I keep getting an error:

$ sudo ln -s /private/etc /etc
sudo: unable to stat /etc/sudoers: No such file or directory
sudo: no valid sudoers sources found, quitting
sudo: unable to initialize policy plugin

Any help would be appreciated, thanks.

Output of ls -l /etc:

$ ls -l /etc
ls: /etc: No such file or directory

My /etc was symlinked to /private/etc (sudoers is in there).

Best Answer

Boot to Recovery Mode (cmd-R)
Open Terminal from the menubar Utilities > Terminal
Soft-link /private/etc to /etc on your main Volume:
```
ln -s private/etc /Volumes/Macintosh\ HD/etc 
```
Replace Macintosh\ HD with the name of your main volume (if your forgot it, just enter df or ls /Volumes/ and check for its name! Don't forget to escape blanks with a backslash.)

Related Solutions

MacOS – How to you avoid error -43 when copying symlinked folder in Finder with a SAMBA share

In your configuration, you have unix extensions = no which is fine, but that is why symbolic links on the server are showing up as folders and not aliases. In this mode the server resolves the symbolic links and the client never sees them. If the client tries to create a symbolic link, the server actually generates an alias file, not a host-OS symbolic link. Reasons for this include security (preventing someone from getting access to /etc/passwd on the server by creating a symbolic link to it) and client compatibility, as OS X and Windows and Unix have slightly different ideas about what constitutes a symbolic link but they pretty much agree on what is a directory or a file.

Permissions issues with SAMBA are complex, so it's not clear that you do not have a permissions issue. Likewise symbolic like resolving is complex, so it is not clear that what you are doing should, in theory work, and there's always the possibility of a bug (most likely in the SAMBA server).

When accessing a SAMBA server from a Mac, these identities and permissions are involved:

The Mac User you are logged into the Mac as
The SAMBA user you are logged into the SAMBA server as
The SMABA server host OS user you get converted to
Unix-style file permissions
For NTFS and HFS+, associated file-system ACLs

So even though you have provided a lot of information, it's still not clear that you are not having permissions problems. The fact that you can mv and cp on the server (using what account?) does not mean you do not have a permissions problem preventing you from doing it on the client (using what accounts and with what effective account on the server?).

If the server is supporting ACLs and since you have options like inherit permissions = yes and inherit acls = yes set there could be some kind of ACL problem that is only allowing read access to directories accessed via symbolic links. There are several other avenues of investigation based on the server configuration.

I would really expect you should be able to find more information in the SAMBA server logs than you have communicated. They should give you a much better sense of exactly what is being denied.

For what it is worth, I tried to duplicate your setup using an Ubuntu 12.04 host as the SAMBA server and could not reproduce your problem. Symbolic links worked for me as expected.

Sudo: /etc/sudoers is owned by uid 501, should be 0

You can boot into single user mode by pressing Cmd-S on startup (see OS X: How to start up in single-user or verbose mode for details) which should give you a root shell. Then run

mount -uw /
chown root:wheel /etc/sudoers
chmod 440 /etc/sudoers
reboot

to fix the problem and restart.

Best Answer

Related Solutions

MacOS – How to you avoid error -43 when copying symlinked folder in Finder with a SAMBA share

Sudo: /etc/sudoers is owned by uid 501, should be 0

Related Question