we had a bit of trouble with open network ports recently and I now think security of MIDAS RPC 
ports needs to be tightened.

TL;DR, this is a non-trivial network configuration problem, TL required, DR up to you.

as background, right now we have two settings in ODB, "/expt/security/enable non-localhost 
RPC" set to "no" (the default) and set to "yes". Set to "no" is very secure, all RPC sockets 
listen only on the "localhost" interface (127.0.0.1) and do not accept connections from other 
computers. Set to "yes", RPC sockets accept connections from everywhere in the world, but 
immediately close them without reading any data unless connection origins are listed in ODB 
"/expt/security/RPC hosts" (white-listed).

the problem, one. for security and robustness we place most equipments on a private network 
(192.168.1.x). MIDAS frontends running on these equipments must connect to MIDAS running on 
the main computer. This requires setting "enable non-localhost RPC" to "yes" and white-listing 
all private network equipments. so far so good.

the problem, one, continued. in this configuration, the MIDAS main computer is usually also 
the network gateway (with NAT, IP forwarding, DHCP, DNS, etc). so now MIDAS RPC ports are open 
to all external connections (in the absence of restrictive firewall rules). one would hope for 
security-through-obscurity and expect that "external threat actors" will try to bother them, 
but in reality we eventually see large numbers of rejected unwanted connections logged in 
midas.log (we log the first 10 rejected connections to help with maintaining the RPC 
connections white-list).

the problem, two. central IT do not like open network ports. they run their scanners, discover 
the MIDAS RPC ports, complain about them, require lengthy explanations, etc.

it would be much better if in the typical configuration, MIDAS RPC ports did not listen on 
external interfaces (campus network). only listen on localhost and on private network 
interfaces (192.168.1.x).

I am not yet of the simplest way to implement this. But I think this is the direction we 
should go.

P.S. what about firewall rules? two problems: one: from statistic-of-one, I make mistakes 
writing firewall rules, others also will make mistakes, a literally fool-proof protection of 
MIDAS RPC ports is needed. two: RHEL-derived Linuxes by-default have restrictive firewall 
rules, and this is good for security, except that there is a failure mode where at boot time 
something can go wrong and firewall rules are not loaded at all. we have seen this happen. 
this is a complete disaster on a system that depends on firewall rules for security. better to 
have secure applications (TCP ports protected by design and by app internals) with firewall 
rules providing a secondary layer of protection.

P.P.S. what about MIDAS frontend initial connection to the mserver? this is currently very 
insecure, but the vulnerability window is very small. Ideally we should rework the mserver 
connection to make it simpler, more secure and compatible with SSH tunneling.

P.P.S. Typical network diagram:

internet - campus firewall - campus network - MIDAS host (MIDAS) - 192.168.1.x network - power 
supplies, digitizers, MIDAS frontends.

P.P.S. mserver connection sequence:

1) midas frontend opens 3 tcp sockets, connections permitted from anywhere
2) midas frontend opens tcp socket to main mserver, sends port numbers of the 3 tcp sockets
3) main mserver forks out a secondary (per-client) mserver
4) secondary mserver connects to the 3 tcp sockets of the midas frontend created in (1)
5) from here midas rpc works
6) midas frontend loads the RPC white-list
7) from here MIDAS RPC sockets are secure (protected by the white-list).

(the 3 sockets are: RPC recv_sock, RPC send_sock and event_sock)

P.P.S. MIDAS UDP sockets used for event buffer and odb notifications are secure, they bind to 
localhost interface and do not accept external connections.

K.O.

One thing coming to my mind is the interface binding. If you have a midas host with two networks 
("global" and "local"=192.168.x.x), you can tell to which interface a socket should bind. 
By default it binds both interfaces, but we could restrict the socket only to bind to the local 
interface 192.168.x.x. This way the open port would be invisible from the outside, but from 
your local network everybody can connect easily without the need of a white list.

Stefan

Good afternoon,

After updating Midas to the latest develop commit 
(0f5436d901a1dfaf6da2b94e2d87f870e3611cf1) we found out a bug when starting 
sequencer. If we have a simple loop from start value to stop value and step 
size, just printing the value at each iteration, we see everything good (see 
first attachment). Then we included another script though, which contains 
several subroutines we defined for our detector, and we try to run the same 
script. Unfortunately after this the parameters seem uninitialized, and the 
value at each loop does not make sense (see second attachment). Also, sometimes 
when pressing run the set parameter window would pop-up, but sometimes not.

The script is this one:

>>>
COMMENT Test script to check for a specific bug

INCLUDE global_basic_functions

#CALL setup_paths
#CALL generate_DUT_params

PARAM lv_start, "Start of LV", 1.8
PARAM lv_stop, "Stop of LV", 2.1
PARAM lv_step, "Step of LV", 0.02

n_iterations = (($lv_stop - $lv_start)/$lv_step)

MSG "Parameters:"
MSG $lv_start
MSG $lv_stop
MSG $lv_step
MSG $n_iterations

MSG "Start of looping"

LOOP n, $n_iterations
   lv_now = $lv_start + $n * $lv_step
   MSG $lv_now
   WAIT SECONDS, 1
ENDLOOP
<<<

and the only difference comes from commenting the line:

>>>
INCLUDE global_basic_functions
<<<

as global_basic_functions is defined as a LIBRARY and it includes 75 (!) 
subroutines...

Is it possible that when loading a large script it messes up the loading of 
parameters?

Thank you very much,
Regards,
Luigi.

Could you please export and send me the /Sequencer ODB tree (or just /Sequencer/Param and /Sequencer/Variables) in both cases while the sequence is running. 

thanks,
Zaher


> Good afternoon,
> 
> After updating Midas to the latest develop commit 
> (0f5436d901a1dfaf6da2b94e2d87f870e3611cf1) we found out a bug when starting 
> sequencer. If we have a simple loop from start value to stop value and step 
> size, just printing the value at each iteration, we see everything good (see 
> first attachment). Then we included another script though, which contains 
> several subroutines we defined for our detector, and we try to run the same 
> script. Unfortunately after this the parameters seem uninitialized, and the 
> value at each loop does not make sense (see second attachment). Also, sometimes 
> when pressing run the set parameter window would pop-up, but sometimes not.
> 
> The script is this one:
> 
> >>>
> COMMENT Test script to check for a specific bug
> 
> INCLUDE global_basic_functions
> 
> #CALL setup_paths
> #CALL generate_DUT_params
> 
> PARAM lv_start, "Start of LV", 1.8
> PARAM lv_stop, "Stop of LV", 2.1
> PARAM lv_step, "Step of LV", 0.02
> 
> n_iterations = (($lv_stop - $lv_start)/$lv_step)
> 
> MSG "Parameters:"
> MSG $lv_start
> MSG $lv_stop
> MSG $lv_step
> MSG $n_iterations
> 
> MSG "Start of looping"
> 
> LOOP n, $n_iterations
>    lv_now = $lv_start + $n * $lv_step
>    MSG $lv_now
>    WAIT SECONDS, 1
> ENDLOOP
> <<<
> 
> and the only difference comes from commenting the line:
> 
> >>>
> INCLUDE global_basic_functions
> <<<
> 
> as global_basic_functions is defined as a LIBRARY and it includes 75 (!) 
> subroutines...
> 
> Is it possible that when loading a large script it messes up the loading of 
> parameters?
> 
> Thank you very much,
> Regards,
> Luigi.

Ok, here is the complete code to reproduce the problem. Load parameter_test.msl which includes functions.msl. From the screenshot you see the variables containing 
garbage, and you also see that from the ODB screenshot. For completeness, I added Sequencer.json which contains the whole sequencer tree.

The interesting thing is that this works sometimes, and sometimes not. I'm not sure if this in the GUI or in the sequencer program, so we have to sort out who can 
fix it ;-)

Best,
Stefan

It is pretty much the same as Stefan, I attach here the screenshots. Also in my case it works sometimes, and sometimes partially (one or 2 params, like in 
attachment 3).

> Could you please export and send me the /Sequencer ODB tree (or just /Sequencer/Param and /Sequencer/Variables) in both cases while the sequence is running. 
> 
> thanks,
> Zaher
> 
> 
> > Good afternoon,
> > 
> > After updating Midas to the latest develop commit 
> > (0f5436d901a1dfaf6da2b94e2d87f870e3611cf1) we found out a bug when starting 
> > sequencer. If we have a simple loop from start value to stop value and step 
> > size, just printing the value at each iteration, we see everything good (see 
> > first attachment). Then we included another script though, which contains 
> > several subroutines we defined for our detector, and we try to run the same 
> > script. Unfortunately after this the parameters seem uninitialized, and the 
> > value at each loop does not make sense (see second attachment). Also, sometimes 
> > when pressing run the set parameter window would pop-up, but sometimes not.
> > 
> > The script is this one:
> > 
> > >>>
> > COMMENT Test script to check for a specific bug
> > 
> > INCLUDE global_basic_functions
> > 
> > #CALL setup_paths
> > #CALL generate_DUT_params
> > 
> > PARAM lv_start, "Start of LV", 1.8
> > PARAM lv_stop, "Stop of LV", 2.1
> > PARAM lv_step, "Step of LV", 0.02
> > 
> > n_iterations = (($lv_stop - $lv_start)/$lv_step)
> > 
> > MSG "Parameters:"
> > MSG $lv_start
> > MSG $lv_stop
> > MSG $lv_step
> > MSG $n_iterations
> > 
> > MSG "Start of looping"
> > 
> > LOOP n, $n_iterations
> >    lv_now = $lv_start + $n * $lv_step
> >    MSG $lv_now
> >    WAIT SECONDS, 1
> > ENDLOOP
> > <<<
> > 
> > and the only difference comes from commenting the line:
> > 
> > >>>
> > INCLUDE global_basic_functions
> > <<<
> > 
> > as global_basic_functions is defined as a LIBRARY and it includes 75 (!) 
> > subroutines...
> > 
> > Is it possible that when loading a large script it messes up the loading of 
> > parameters?
> > 
> > Thank you very much,
> > Regards,
> > Luigi.

I have been able to reproduce the problem only once. From what I see, it seems that the Variables ODB tree is not initialized properly from the Param tree. Below are the messages from the failed run compared to a successful one. As far as I could see, the javascript code does not change anything in the Variables ODB tree (only monitors it). The actual changes are done by the sequencer program, or am I wrong?

Failed run:
16:14:25.849 2024/05/03 [Sequencer,INFO]  + 3 * 
16:14:24.722 2024/05/03 [Sequencer,INFO]  + 2 * 
16:14:23.594 2024/05/03 [Sequencer,INFO]  + 1 * 
16:14:23.592 2024/05/03 [Sequencer,INFO] Start of looping
16:14:23.591 2024/05/03 [Sequencer,INFO] (( - )/)
16:14:23.591 2024/05/03 [Sequencer,INFO] 
16:14:23.590 2024/05/03 [Sequencer,INFO] 
16:14:23.590 2024/05/03 [Sequencer,INFO] 
16:14:23.589 2024/05/03 [Sequencer,INFO] Parameters:
16:14:23.562 2024/05/03 [Sequencer,TALK] Sequencer started with script "testpars.msl".


Successful run:
16:15:37.472 2024/05/03 [Sequencer,INFO] 1.820000
16:15:37.471 2024/05/03 [Sequencer,INFO] Start of looping
16:15:37.471 2024/05/03 [Sequencer,INFO] 15
16:15:37.470 2024/05/03 [Sequencer,INFO] 0.020000
16:15:37.470 2024/05/03 [Sequencer,INFO] 2.100000
16:15:37.469 2024/05/03 [Sequencer,INFO] 1.800000
16:15:37.469 2024/05/03 [Sequencer,INFO] Parameters:
16:15:37.450 2024/05/03 [Sequencer,TALK] Sequencer started with script "testpars.msl".

Ahh, that rings a bell:

1) JS opens start dialog box
2) User enters parameters and presses start
3) JS writes parameters
4) JS starts sequencer
5) Sequencer copies parameters to variables

Now how do you handle 3) and 4). Just issue two mjsonrpc commands together? What then could happen is that 4) is executed before 3) and we get the garbage.
You have to do 3) and WAIT for the return ("then" in the JS promise), and only then issue 4) from there.

Stefan

Thanks for the hint Stefan. I pushed a possible fix but I cannot test it since I cannot reproduce the issue.

> Ahh, that rings a bell:
> 
> 1) JS opens start dialog box
> 2) User enters parameters and presses start
> 3) JS writes parameters
> 4) JS starts sequencer
> 5) Sequencer copies parameters to variables
> 
> Now how do you handle 3) and 4). Just issue two mjsonrpc commands together? What then could happen is that 4) is executed before 3) and we get the garbage.
> You have to do 3) and WAIT for the return ("then" in the JS promise), and only then issue 4) from there.
> 
> Stefan

Seems to me like the problem happens less frequently, but I still see it (1 out of 5 or so). The fact that /Sequencer/Params/Value is empty tells me that the GUI 
has the problem and not the sequencer side.

Stefan

[quote="Zaher Salman"]I think that I finally managed to fix the problem. The default values of the parameters are now written first in one go, then the sequencer waits for confirmation that everything is completed before proceeding. Please test and let me know if there are still any issues. Zaher [/quote]

I am updating the TRIUMF IRIS experiment to the latest version of MIDAS. I see following error messages in midas.log:

19:06:16.806 2024/05/16 [mhttpd,ERROR] [odb.cxx:6967:db_get_data_index,ERROR] index (29) exceeds array length (20) for key 
"/Equipment/Beamline/Variables/Measured"

19:06:15.806 2024/05/16 [mhttpd,ERROR] [odb.cxx:6967:db_get_data_index,ERROR] index (30) exceeds array length (20) for key 
"/Equipment/Beamline/Variables/Measured"

The errors are correct, there is only 20 elements in that array. The errors are coming every few seconds, they spam midas.log. How do I fix 
them? Where do they come from? There is no additional diagnostics or information to go from.

In the worst case, they come from some custom web page that reads wrong index variables from ODB. mhttpd currently provides no diagnostics to 
find out which web page could be causing this.

But maybe it's internal to MIDAS? I save odb to odb.json, "grep Measured odb.json" yields:
iris00:~> grep Measured odb.json 
        "Condition" : "/Equipment/Beamline/Variables/Measured[29] > 1e-5",
        "Condition" : "/Equipment/Beamline/Variables/Measured[30] < 0.5",

So wrong index errors is coming from evaluated alarms.
ODB "/Alarms/Alarm system active" is set to "no" (alarm system is disabled), the errors are coming.
ODB "/Alarms/Alarms/TP4/Active" is set to "no" (specific alarm is disabled), the errors are coming.
WTF? (and this is recentish borkage, old IRIS MIDAS had the same wrong index alarms and did not generate these errors).

Breakage:
- where is the error message "evaluated alarm XXX cannot be computed because YYY cannot be read from ODB!"
- disabled alarm should not be computed
- alarm system is disabled, alarms should not be computed

K.O.

P.S. I am filing bug reports here, I cannot be bothered with the 25-factor authentication to access bitbucket.

This is a common problem I also encountered in the past. You get a low-level ODB access error (could also be a read of a non-existing key) and you 
have no idea where this comes from. Could be the alarm system, a mhttpd web page, even some user code in a front-end over which the midas library 
has no control.

One option would be to add a complete stack dump to each of these error (ROOT does something like that), but I hear already people shouting "my 
midas.log is flooded with stack dumps!". So what I do in this case is I run a midas program in the debugger and set a breakpoint (in your case at 
odb.cxx:6967). If the breakpoint triggers, I inspect the stack and find out where this comes from.

Not that I print a stack dump for such error in the odbxx API. This goes to stdout, not the midas log, and it helped me in the past. Unfortunately 
stack dumps work only under linux (not MacOSX), and they do not contain all information a debugger can show you.

It is not true that alarm conditions are evaluated when the alarm system is off. I just tried and it works fine. The code is here:

alarm.cxx:591

      /* check global alarm flag */
      flag = TRUE;
      size = sizeof(flag);
      db_get_value(hDB, 0, "/Alarms/Alarm system active", &flag, &size, TID_BOOL, TRUE);
      if (!flag)
         return AL_SUCCESS;

so no idea why you see this error if you correctly st "Alarm system active" to false.

Stefan

> This is a common problem I also encountered in the past. You get a low-level ODB access error (could also be a read of a non-existing key) and you 
> have no idea where this comes from. Could be the alarm system, a mhttpd web page, even some user code in a front-end over which the midas library 
> has no control.

committed a partial fix, added an error message in alarm condition evaluation code to report alarm name and odb paths when we cannot get something from 
ODB. Now at least midas.log gives some clue that ODB errors are coming from alarms.

and the errors are actually coming from the alarms web page.

the alarms web page shows all the alarms even if alarms are disabled and it shows evaluated alarm conditions and current values even for alarms that 
are disabled.

I could change it to show "disabled" for disabled alarms, but I think it would not be an improvement,
right now it is quite convenient to see the alarm values for disabled/inactive alarms,
it is easy to see if they will immediately trip if I enable them. Hiding the values would make
them blind.

And I think I know what caused the original problem in IRIS experiment, I think the list of EPICS variables got truncated from 30 to 20 and EPICS 
values 29 and 30 used in the alarm conditions have become lost.

So the next step is to fix feepics to not truncate the list of variables (right now it is hardwired to 20 variables) and restore
the lost variable definition from a saved odb dump.

K.O.






> 
> One option would be to add a complete stack dump to each of these error (ROOT does something like that), but I hear already people shouting "my 
> midas.log is flooded with stack dumps!". So what I do in this case is I run a midas program in the debugger and set a breakpoint (in your case at 
> odb.cxx:6967). If the breakpoint triggers, I inspect the stack and find out where this comes from.
> 
> Not that I print a stack dump for such error in the odbxx API. This goes to stdout, not the midas log, and it helped me in the past. Unfortunately 
> stack dumps work only under linux (not MacOSX), and they do not contain all information a debugger can show you.
> 
> It is not true that alarm conditions are evaluated when the alarm system is off. I just tried and it works fine. The code is here:
> 
> alarm.cxx:591
> 
>       /* check global alarm flag */
>       flag = TRUE;
>       size = sizeof(flag);
>       db_get_value(hDB, 0, "/Alarms/Alarm system active", &flag, &size, TID_BOOL, TRUE);
>       if (!flag)
>          return AL_SUCCESS;
> 
> so no idea why you see this error if you correctly st "Alarm system active" to false.
> 
> Stefan

Trying to restore IRIS ODB was a nasty surprise, old save files are in .odb format and odbedit "load xxx.odb" 
does an unexpected thing.

mkdir tmp
cd tmp
load odb.xml loads odb.xml into the current directory "tmp"
load odb.json same thing
load odb.odb loads into "/" unexpectedly overwriting everything in my ODB with old data

this makes it impossible for me to restore just /equipment/beamline from old .odb save file (without 
overwriting all of my odb with old data).

I look inside db_paste() and it looks like this is intentional, if ODB path names in the odb save file start 
with "/" (and they do), instead of loading into the current directory it loads into "/", overwriting existing 
data.

The fix would be to ignore the leading "/", always restore into the current directory. This will make odbedit 
load consistent between all 3 odb save file formats.

Should I apply this change?

K.O.

> 
> And I think I know what caused the original problem in IRIS experiment, I think the list of EPICS variables got truncated from 30 to 20 and EPICS 
> values 29 and 30 used in the alarm conditions have become lost.
> 
> So the next step is to fix feepics to not truncate the list of variables (right now it is hardwired to 20 variables) and restore
> the lost variable definition from a saved odb dump.

for the record, I restored the old ODB settings from feepics, my EPICS variables now have the correct size and the alarm now works correctly.

I also updated the example feepics to read the number of EPICS variables from ODB instead of always truncating them to 20 (IRIS MIDAS had a local change 
setting number of variables to 40).

I think I will make no more changes to the alarms, leave well enough alone.

K.O.

For everybody using EPICS: There is now a new system called MSetPoint (Midas Set Point) to control whole beamlines via EPICS.
It's under midas/msetpoint and the documentation is here:

   https://bitbucket.org/tmidas/midas/wiki/MSetPoint

It is basically an EPICS frontend and two custom pages. The special thing is that the EPICS elements are not hardcoded in
the frontend but come from the ODB. There is even an editor for the beamline elements (second custom page). By loading different
ODB settings, one can switch easily between completely different beamlines without having to recompile the frontend. The system
can be operated standalone (all other MIDAS pages do not appear), or as a custom page in a normal midas setup. At PSI, this
system is now used as the standard editor for our beamlines.

Attached and example screen.

Stefan

For everybody using EPICS: There is now a new system called MSetPoint (Midas Set Point) to control whole beamlines via EPICS.
It's under midas/msetpoint and the documentation is here:

   https://bitbucket.org/tmidas/midas/wiki/MSetPoint

It is basically an EPICS frontend and two custom pages. The special thing is that the EPICS elements are not hardcoded in
the frontend but come from the ODB. There is even an editor for the beamline elements (second custom page). By loading different
ODB settings, one can switch easily between completely different beamlines without having to recompile the frontend. The system
can be operated standalone (all other MIDAS pages do not appear), or as a custom page in a normal midas setup. At PSI, this
system is now used as the standard editor for our beamlines.

Attached and example screen.

Stefan