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My machine is mymac and the remote machine is remotemac(both are running El Capitan 10.11.6) - I reference a share on remotemac, located at //remotemac/path/to/remoteshare, as /Volumes/remoteshare.

Sometimes, especially when I have recently connected to that remote machine or share from Finder, the /Volumes/remoteshare path is available. But after some time, that /Volumes/remoteshare path is not available. 

$ ls /Volumes
Macintosh HD
$ # connect to remoteshare from Finder
$ ls /Volumes
$ Macintosh HD    remoteshare
# After some time (a few hours)...
$ ls /Volumes
Macintosh HD 
$ # note that /Volumes/remoteshare is now missing

What can I do in my bash script to ensure that the remoteshare volume is present, or created before it is referenced?

Anand
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1 Answers1

1

In a script you can use the following basic construct:

#!bin/bash

if mount | grep -q "remoteshare"; then # check if remoteshare is available 
    exit
else
    echo not found
fi

grep -q ... suppresses normal output. If successful the script exits. In the other case it will echo "not found".

Instead of echo not found you can ssh into the remote server, run serveradmin and enable or restart the smb service – man serveradmin will show you how to do this. Then quit the ssh session and try to remount the SMB share.

To ssh passwordless into the server enable key based authentication - passing a password in a script is insecure and error prone. To use serveradmin on the remote server without sudoing, modify /etc/sudoers on the remote server and change the part:

## User privilege specification
##
root ALL=(ALL) ALL
%admin  ALL=(ALL) ALL

to

## User privilege specification
##
root ALL=(ALL) ALL
%admin  ALL=(ALL) ALL
your_remote_username ALL=(ALL) NOPASSWD: /Applications/Server.app/Contents/ServerRoot/usr/sbin/serveradmin

Instead of the line echo not found use something like this then:

ssh username@remotemac
serveradmin stop smb
sleep 10
serveradmin start smb
sleep 2
exit
echo "SMB service was restarted"
mount_smbfs //your_remote_username:password@remotemac/folder /some/mntpoint

The inaccessibility of an SMB share may have many causes. It's probably impossible to cover all cases in one script.

Community
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klanomath
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  • Thanks - this alternative sounds insecure - I am essentially trusting my user name to ssh into the remote machine - how does Finder manage to open the remote share when I click on the (remotemac) share link in Finder sidebar? Does it use sudo? I would like to make my script be as secure as that experience. – Anand Aug 14 '16 at 07:18
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    @Anand key based ssh authentication is usually more secure than password based auth. – klanomath Aug 14 '16 at 07:20
  • Agreed, I am trying to understand how Finder does it (and do the same). Obviously Finder on my client does not require these edits to the remote machine settings - any client Finder window in the network is able to find the shares I am looking for. – Anand Aug 14 '16 at 07:23
  • @Anand you can also include Apple Script in your bash script with ...osascript.. and use the FInder – klanomath Aug 14 '16 at 07:31
  • I was just looking into AppleScript to do this :-) Could you post a solution for this that uses AppleScript within bash? Thanks! – Anand Aug 14 '16 at 07:42
  • @Anand I don't know whether Server.app is scriptable or not - I don't think it's as easy as the cli. The problem here is, that I don't know what's wrong with the SMB server. The spontaneous unmounts may be a time-out or a smb/OS X bug. – klanomath Aug 14 '16 at 07:57
  • Thanks. This issue is fairly consistent - after some time (at least a few minutes), with no finder window connected to the remote, the volumes just disappear - this has been happening for a while now, at least as far back as Yosemite. – Anand Aug 14 '16 at 17:22