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Pi MeshChat Error Sending Message

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Pi MeshChat Error Sending Message
We are trying to setup MeshChat on Raspberry Pi's and have 2 issues.
1: is the Error Sending Message: Could not get Lock.
2: We don't see chats from the same Zone as on the regular MeshChats

One of the Pi's is on a Pi2 and one is Pi3, both are running Jessie Stretch Desktop
Any help would appreciated
K5DLQ's picture
You might try reaching out to
You might try reaching out to the author, K7FPV
Both Roger and I emailed him,

Both Roger and I emailed him, I guess he's real busy and referred Roger to the forum. 
Here's additional info, maybe someone can give me a hint where to look:

Meshchat was installed following the directions. Looks to have installed properly. In fact it's syncing with the other nodes on our network, populating it's database with all the texts from the other nodes just fine. Nothing make it to the Web interfact though. The problem is when we try to send a text we get the message Could not get Lock.

Looking in /var/log/apache2/error.log, I see many of:
touch : cannot touch '/tmp/meshchat/lock' : No such file or directory.
clould not get lock at /usr/lib/cgi-bin/ line 35

However the file does exist and if I delete it, it's instantly re-created. There is plenty of file activity in that directory as Meshchat syncs with the other nodes.
We're both running the latest version of Raspbian from the site.

Any idea what's happening and what went wrong? I'm not a linux guru or even much of a programmer, but I've been playing with Linux since Linus released it when I had a 386SX/25 and had to install it from floppies.


Try these commands on your pi
Try these commands on your pi:

mkdir -p /tmp/meshchat
touch /tmp/meshchat/lock
chown -R www-data:www-data /tmp/meshchat
chown www-data:www-data /tmp/meshchat/lock

Wait a few mins and try, if still not working:

/etc/init.d/meshchatsync restart

OK, tried that. No change.

OK, tried that. No change. Both directory and file show owner/group as www-data. Everything is working with syncing with other nodes, MeshChat's database is getting all the text from other nodes, just can't display on web page.

I  thought I'd try an older version of OS, installed on a version of Jessie from 9/2016. WORKS right off! Something has changed in Raspbian.

w8awt's picture
Have you found a fix? I'm
Have you found a fix? I'm having exactly the same problem. I cant see anything comming  from my nodes and I cant post anything using meshchat installed on the Pi.

I haven't had the time to
I haven't had the time to look into this further. Maybe sometime in the next month. Nobody else has responded and neither has the author of MeshChat.
August KG7BZ
w8erw's picture
MeshChat Pi
I am also having the same issues with a Pi 3 and Raspbian Stretch.  I have had a couple of additional non related issues as well.  I am beginning to think this all may be a Pi 3/Stretch problem.  It appears that something(s) are lacking in this combination.  I have a battery backup hat that will not configure correctly, a real time clock which does the same and now MeshChat does not operate as intended.  I have kept up with th Pi upgrades thinking this may solve the problems which has not happened.
Jim W8ERW 
K5DLQ's picture
looks like a permissions
looks like a permissions issue to me....
Works on older OS

Just so others who are having the same problem see it, MeshChat Pi works on a 9/2016 version of Jessie. Does not work on the newer Stretch from 2017.

Don't stretch it or you'll break it
Agreed... Did two clean installs and confirmed it works up to 7/5/2017 Jessie. Something in Stretch breaks it.
w6bi's picture
Sounds like my problem.
My MeshChat nodes stopped working recently and I suspect that's the issue, as I believe they've all been upgraded to Stretch.  I'll check.
KS7P's picture
Has a fix for this problem been made?  I too am trying to setup a new node with MeshChat and get the 'Could not get Lock' message.  Running Raspian/stretch.
K5DLQ's picture
downgrade to Jessie
downgrade to Jessie
KL7VK's picture
Meshchat on RPI
New to BBHN and what is the advantage in running Meshchat on an RPI as opposed to running Meshchat on station radio as a "package?"
It is recommend to NEVER run
It is recommend to NEVER run add-on software on the mesh node. Add-on programs consume valuable limited resources on a mesh node that could be better served letting the node do what it is built to do which is route packets in a high speed manner.

In addition the AREDN team doesn't support unofficial packages, any adddon software will often be asked to be removed before any support is given for issues .
K5DLQ's picture
And running it on a Pi you
And running it on a Pi you get additional features (automated actions) and MUCH more storage space to serve files.
AC7BR's picture
One way to fix this issue

I put a new Pi, based on Raspanian Stretch, on our local mesh yesterday and had the same issues outlined in this thread.  After some investigation, I have a fix for the issue.  Before I outline the fix, I should note that the problem isn't the MeshChat software, but rather it is in the systemd startup config for Apache.  The systemd startup config specifies that a private /tmp directory should be used for the Apache process.  Because of this, the Apache process cannot see the /tmp/meshchat directory, including the lock file in that directory.  This causes all the errors you see in the Apache log file.

To fix this issue, do the following:

  • Shutdown the Apache process via the command 'sudo systemctl stop apache2'
  • Copy the Apache2 startup config to the user systemd area.  The command is 'cp /lib/systemd/system/apache2.service /etc/systemd/system/apache2.service'
  • Using your favorite editor, modify /etc/systemd/system/apache2.service and change the PrivateTmp=true parameter to PrivateTmp=false
  • Restart the Apache process via the command 'sudo systemctl start apache2'

MeshChat on a Stretch based Raspberry Pi should work now.

An alternative fix is to change the MeshChat code to use a different path.  This can be done by changing the Perl $meshchat_path variable in /usr/lib/cgi-bin/  I didn't go down this path because if you ever update the MeshChat package this change would be lost unless Trevor made a similar change in his code.



AC7BR's picture
One other thing
One other thing I did is to change the permissions on the lock file as it was only read/write by root.  To do this, run the command
  • chmod 0666 /tmp/meshchat/lock
I did this prior to finding the fix I outline above.  I don't know if there is code in MeshChat to take care of the permissions but if the fix above doesn't work try this too.

KB5UGF's picture
Those 2 fixes worked!
I tried both of your suggestions, both the  Apache2 config mod and the permissions change, and it worked like a charm. Thanks!
MeshChat "Error Sending Message: Could not get lock" FIXED!

I just dealt with this problem on my Pi 4 with Raspian GNU/Linux 11 (bullseye).  I read through the thread and indeed got things working.  Here were the commands I issued:

'sudo chmod 0666 /tmp/meshchat/lock'

Shutdown the Apache process via the command 'sudo systemctl stop apache2'

Copy the Apache2 startup config to the user systemd area.  The command is 'sudo cp /lib/systemd/system/apache2.service /etc/systemd/system/apache2.service'

Using your favorite editor, modify /etc/systemd/system/apache2.service and change the PrivateTmp=true parameter to PrivateTmp=false

'sudo systemctl daemon-reload'

Restart the Apache process via the command 'sudo systemctl start apache2'

This took care of the "Error Sending Message: Could not get Lock" issue.

Now I'm left with a lesser situation where when files are added, they are for some reason listed twice on the MeshChat "Files Available" listing.  More to research.

Thanks for this thread.


Kent, KL5T

VE7JEY's picture
Hi Brad, I just signed up to
Hi Brad, I just signed up to this forum so I could thank you, and the others, for answering this issue. Its Mar 2021 and the problem still arises. Luckily I came across this thread even before I moved my test meshchat from inside my node on to the Pi. I've only been at it a few weeks and bought a GL AR150 for lowest price and ease of install. Still working out the best layout of Pi, Laptop, Routers, Switch, power, Node, and home network.
So, thanks for the instructions - and, as with some others, I also needed the important DAEMON command. Cheers, John VE7JEY on Vancouver Island
KM6IAU's picture
 Thank you very much
yes Thank you very much
WH6GJL's picture
I was still having problems
I was still having problems with apache not accessing the tmp folder

Seems that running
sudo systemctl daemon-reload
sudo systemctl start apache2

did the trick for me to reload the proper configuration before starting apache
Thank you, Brad!

Thank you, Brad!

Followed your instructions to fix the "Error Sending Message: Could not get Lock" issue.  Everything works great now!  I will have to document this in my offline book of tricks.


KF7BWS's picture
One way to fix this issue
Brad AC7BR
did not work.
Thank You
Really appreciate the information got me up and going!
Thanks Brad!  That fixed my

Thanks Brad!  That fixed my MeshChat problem and now after months (since I upgraded to Stretch), it is up and running again.  I did have to do the permissions change to get file uploading to work.  All seems well now!
73 - Mike ab4yy

Yet another...

I ran into this problem on a new 3B+ I bought from Newark at Hamvention this weekend to replace my 3B on Jesse. Then I came here.

Brad, you're my hero! Thank you!

MeshChat on a raspberry Pi - one way message sync.
I have just set up a meshchat node on a raspberry Pi.  It is on the 3B+

After doing a clean install on the Pi & installing meshchat, I followed the instructions by AC7BR
1 - changing the PrivateTmp=false
2 - ​chmod 0666 /tmp/meshchat/lock

I was able to clear the lock error and send a message.
I then jumped on another node and saw my message appear.- sending from my node works!!

The only problem I have left is how to get the sync working both ways.  My node sends messages but does not receive (When on the other node, I sent a message and it did not appear on my node).

Any thoughts on what I need to look at?


Peter - AK6PW
K5DLQ's picture
from memory, you need to
from memory, you need to install the meshchat_api packages on one of your local nodes and configure meshchat to use it.  That's how it determines what other meshchat services are available on the network.
MeshChat on a raspberry Pi - all functional
That was it - missed the step to install the api package on the node - once done and rebooted, messaging both ways kicked in

Thank you!!
K6CCC's picture
Don't forget to reinstall api after update.
And don't forget that if you update software on the AREDN node, you get to re-install the api package.  I missed that step.

I had installed the api several days ago, and confrmed that it was there.  Today installed the newest nightly build, and then spent a while getting MeshChat working on a RasPi here.  It was working only one way.  Finally checked for installed packages on the node and it was not there.  Re-installed the api and all of a sudden, MeshChat started syncing with other nodes.  Based on my testing, this is not an uncommon problem.
Tried every suggestion here and still does not work

I have read through every post and tried all the suggestions and still get the lock error.
I did a fresh install of Buster from the Raspbian site. Did the upgrade/update. Installed Apache 2. Installed MeshChat 1.02. No matter what I've tried I can't past the lock error. Not sure where to get a older copy of Raspbian as suggested here however. Very frustrated as I am to demo this for a ham club next Monday. Any help I could get will be greatly appreciated.      

nc8q's picture
where to get a older copy of Raspbian
Thanks. I'll try that tonight
Thanks. I'll try that tonight.
Tried every suggestion here and still does not work Part 2
Before I tried to move to an older OS I tried editing permissions on the meshchat files in ​/var/www/html/ using ​​(sudo chmod 0666 /var/www/html/) and I no longer have the lock error. When I send a message however it just disappears. It used to show up in the lower half of the screen in Messages but no longer does. 
Any suggestions? Thanks again for the help.
KJ6WEG's picture
Similar issues fixed on Raspbian Buster

Thanks to AC7BR for the fix in comment #18!! 
I spent many hours beating my head on this setup, on a new Raspberry Pi 4 running Raspbian Buster.  After solving several other issues, this last one stumped me, and these instructions finally resolved it.  Actually, it didn't work at first... I also had to reboot the Pi to get it to start showing the messages other nodes.  
Thanks AC7BR!

N5MXI's picture

I've tried every suggestion in this forum thread without any luck. New MeshChat install won't sync with other MeshChat nodes and I get the dreaded "Could not get lock error" Anyone want to share an image file of their working MeshChat on a Rpi? 

I have the API loaded on a MikroTik hap ac lite with the latest AREDN firmware. 
MeshChat is installed on a Rpi 3B+ running Stretch (could get Jessie to work with my HDMI display)

I'm open to all suggestions for fixing this thing.

Thanks, David-N5MXI

Image Attachments: 
nc8q's picture
Anyone want to share...

Message #18 in this thread solved the - Could not get lock - error for me.
Please share
that meshchat_1.02_all.ipk is installed on the node.
that the node's [Advertised Services Name] matches the in the RPi;
Example config;
/usr/lib/cg--bin/ our $pi_zone = '[Advertised Service Name]';

I hope this helps, Chuck

AE6XE's picture
There appears to be something
There appears to be something going on in the firewall rules, currently under investigation.   Ref:

N5MXI's picture
What's the verdict?

Joe - I've been following the thread you mentioned in your last message. My brain cell started hurting when you all started talking about IPtables etc... I can't tell if a resolution has been found yet or not. If yes, is there a patch I can load or will installing the nightly build correct the problem?

I also have a MikroTik which is probably the reason my MeshChat won't work. If you need another MikroTik node to be a guinea pig for testing, mine is available. 


AE6XE's picture
David, we have 3 people,
David, we have 3 people, including myself, that have tested the changes with success.  Although I'm not entirely sure if the symptoms you have are new or the same (and same root cause).   I'll push through to get into the nightly build.    Look to upgrade tomorrow and retest to see if your symptoms go away too.

N5MXI's picture
 Thanks will do.
yes Thanks will do.
K6CCC's picture
I see the Nightly Build for
I see the Nightly Build for this came out this morning.  Installed in all 12 of my nodes.  Tunnels are all working, and my MeshChat (on  Pi) is syncing just fine to other Meshchat nodes - although I had not experienced any issuess with that.
N5MXI's picture
Still no joy

Just completed the firmware update on my MikroTik hap ac with the nightly build that was just released. Update loaded fine however I still get the "can't get lock" error message on MeshChat. MeshChat doesn't sync with other nodes.

So the procedure described above didn't work for you?

So the procedure described here/above doesn't work for you?  I suppose you could change the $meshchat_path to "/var/www/html/meshchat" in your /usr/lib/cgi-bin/ file, which would eliminate using the /tmp directory altogether.

This issue typically results from how the Apache web server is configured to allow or deny use of the /tmp directory on Linux.  You'll usually see messages like this in /var/log/apache2/error.log -----   "cannot touch /tmp/meshchat/lock" which causes MeshChat to report that it "could not get a lock"  Either fix the permissions in Apache as described above & change the permissions on the lock file, or point MeshChat to a different $meshchat_path where it can put its lock file.

K6CCC's picture
Did not help.
I just tried the procedure in the link above for David, and it did not help. 
nc8q's picture
install the API package
after the firmware upgrade?

K6CCC's picture
The can't lock message in
The can't lock message in MeshChat is something local to MeshChat, and I don't think has anything to do with the attached node at all.  That sounds like that is local to the MeshChat install.
K5DLQ's picture
i recall the "lock" issue was
i recall the "lock" issue was something to do with the version of Raspbian.   I know this has been asked before, so, you may want to do a quick search.


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