> bk_create()
> frontend.cpp:954: error: invalid conversion from ‘DWORD**’ to ‘void**’

Yes, the original bk_create() prototype was wrong, implying a pointer to the data instead of pointer-to-the-
pointer-to-the-data.

The prototype was corrected recently (within the last 2 years?), but as an unfortunate side-effect, nazi C 
compilers refuse to automatically downgrade "xxx**" to "void**" (when downgrade of xxx* to void* is 
accepted) and a cast is now required.

K.O.

After pulling the newest version of midas, our compilation would fail on
bk_create, with the error:

frontend.cpp:954: error: invalid conversion from ‘DWORD**’ to ‘void**’
frontend.cpp:954: error:   initializing argument 4 of ‘void bk_create(void*,
const char*, WORD, void**)’

I noticed a change to the function in midas.c that changes the type of pdata
from a pointer to a double pointer, and changes 

      *((void **) pdata) = pbk + 1;
to
      *pdata = pbk + 1;

The fix is simple. In each call to bk_create, I changed it to:

bk_create(pevent, bk_name, TID_DWORD, (void**)&pdata); 

I suggest updating the documentation. Also, why the change? Does it add some
improvement in efficiency?

The preliminary version of the .bashrc blurb looks like this
(a couple of flaws:
1) identification of CentOS7 is incomplete - please send me a patch
fixed -> 2) there should be a check for root-config already in the PATH, as on Ubuntu, the ROOT package 
may be installed in /usr and root-
config may be already in the path - please send me patch).

if [ -x $(which root-config) ]; then 
    # root already in the PATH 
    true 
elif [ `uname -i` == "i386" ]; then 
    . /daq/daqshare/olchansk/root/root_v5.34.01_SL62_32/bin/thisroot.sh 
    true 
elif [ `lsb_release -r -s` == "7.1.1503" ]; then 
    #. /daq/daqshare/olchansk/root/root_v5.34.32_SL66_64/bin/thisroot.sh 
    true 
else 
     . /daq/daqshare/olchansk/root/root_v5.34.32_SL66_64/bin/thisroot.sh 
     true 
fi 

> A set of improvements to mlogger is in:

Preliminary support for CRC32-zlib, CRC32C, SHA-256 and SHA-512 is in. Checksums are computed correctly, but plumbing configuration is 
preliminary. Good enough for testing and benchmarking.

To enable checksums, set channel compression:
100 - no checksum (LZ4 compression)
11100 - CRC32-zlib checksum
22100 - CRC32C
33100 - SHA-256
44100 - SHA-512
checksums for both uncompressed and compressed data will be computed and reported into midas.log.

To compare:

CRC32-zlib is for compatibility with gzip and zlib tools
CRC32C is for maximum speed
SHA-256 and SHA-512 is for maximum data security

To remember:

- CRC32-zlib is the CRC32 computation from gzip/png/zlib library. I believe the technical name of the algorithm is "adler32".
- CRC32C is the most recently improved version of CRC32 family of checksums. Implementation is from Mark Adler (same Adler as adler32) uses 
hardware acceleration on recent Intel CPUs.
- SHA-256 and SHA-512 are checksums currently accepted as cryptographically secure. One of them is supposed to be faster on 64-bit 
machines. I implement both for benchmarking.

"Cryptographically secure" means "nobody has a practical way to construct two different files with the same checksum".

In simpler words, the file contents cannot change without breaking the checksum - by software bug, by hardware fault, by benign or malicious 
intent.

The CRC family of checksum functions were never cryptographically secure.
MD5 and SHA-1 used to be secure but are no longer considered to be so. MD5 was definitely broken as different files with the same checksum 
have been discovered or constructed.

K.O.

> Hello, I am new in the forum. We are running an experiment for a week with no
> problems. Now we add a detector a we found an error. Even we come back to our
> previous configuration the error continues appearing. Please, may someone help
> us? You can find the error in the attachment. Thanks!

The error reported is SIGSEGV, which is a software fault (as opposed to a hardware fault like "printer is on fire" or "disk full").

Next step is to identify which program crashed and attach a debugger to the crashing executable or to the core dump.
You will use the debugger to generate the stack trace which will identify exactly the place where the program failed.

I recommend that one should always attach the stack trace to the problem reports on this forum. These stack traces are sometimes long and 
scary and it is a bit of an art to read them, so do not worry if you do not understand what they say.

If you use "gdb", I recommend that you post your full debugger session:

bash> gdb myprogram
gdb> run my command line arguments
*crash*
gdb> where
... stack trace
gdb> quit

(If you use threads, please generate a stack trace for each thread)

If the crash location is inside midas code, congratulations, you may have found a bug in midas.
If the crash location is in your code, you have some debugging to do.
If you do not understand what I am talking about (gdb? core dump?), please read "unix/linux software development for dummies" book first.

K.O.

SIGSEGV is a segmentation fault. Most often it means some ODB parameter is out of bounds or there is 
an invalid memcpy somewhere in your code.

> Hello, I am new in the forum. We are running an experiment for a week with no
> problems. Now we add a detector a we found an error. Even we come back to our
> previous configuration the error continues appearing. Please, may someone help
> us? You can find the error in the attachment. Thanks!

See bitbucket for the solution.

https://bitbucket.org/tmidas/midas/issues/29/jset-odbset-using-true-false-for-booleans#comment-20550474

Hello, I am new in the forum. We are running an experiment for a week with no
problems. Now we add a detector a we found an error. Even we come back to our
previous configuration the error continues appearing. Please, may someone help
us? You can find the error in the attachment. Thanks!

New git branch "feature/rpcsecurity" implements  these security features:

- all UDP ports are bound to the localhost interface - connections from outside are not possible
- by default out of the box MIDAS RPC TCP ports are bound to the localhost interface - connections from the outside are not possible.

This configuration is suitable for testing MIDAS on a laptop and for running a simple experiment where all programs run on one machine.

This configuration is secure (connections from the outside are not possible).

This configuration makes corporate security people happy - MIDAS ports do not show up on network port scans (nmap & etc). (except for the mhttpd 
web ports).

The change in binding UDP ports is incompatible with previous versions of MIDAS (except on MacOS, where UDP ports were always bound to localhost). 
All MIDAS programs should be rebuild and restarted, otherwise ODB hotlinks and some other stuff will not work. If rebuilding all MIDAS programs is 
impossible (for example I have one magic MIDAS frontend that cannot be rebuilt), one can force the old (insecure) behavior by creating a file 
.UDP_BIND_HOSTNAME in the experiment directory (next to .ODB.SHM).

The mserver will still work in this localhost-restricted configuration - one should use "odbedit -h localhost" to connect. Multiple mserver instances on 
the same machine - using different TCP ports via "-p" and ODB "/Experiment/midas server port" - are still supported.

To run MIDAS programs on remote machines, one should change the ODB setting "/Experiment/Security/Enable non-localhost RPC" to "yes" and 
add the hostnames of all remote machines that will run MIDAS programs to the MIDAS RPC access control list in ODB "/Experiment/Security/RPC hosts".

To avoid "guessing" the host names expected by MIDAS, do this: set "enable non-localhost rpc" to "yes" and restart the mserver. Then go to the remote 
machine and try to start the MIDAS program, i.e. "odbedit -h daq06". This will bomb and there will be a message in the midas log file saying - rejecting 
connection from unallowed host 'ladd21.triumf.ca'. Add this host to "/Experiment/Security/RPC hosts". After you add this hostname to "RPC hosts" and 
restart the mserver, the connection should be successful. When "RPC hosts" is fully populated, one should restart all midas programs - the access 
control list is only loaded at program startup.

If MIDAS clients have to connect from random hosts (i.e. dynamically assigned random DHCP addresses), one can disable the host name checks by 
setting ODB "/experiment/security/Disable RPC hosts check" to "yes". This configuration is insecure and should only be done on a private network 
behind a firewall.

After some more testing this branch will be merged into the main midas.

K.O.

There is a number of problems with network security in midas. (as separate from 
web/http/https security).

1) too many network sockets are unnecessarily bound to the external network interface 
instead of localhost (UDP ports are already bound to localhost on MacOS).
2) by default the RPC ports of each midas program accept connections and RPC commands 
from anywhere in the world (an access control list is already implemented via 
/Experiment/Security/Rpc Hosts, but not active by default)
3) mserver also has an access control list but it is not integrated with the access control list 
for the RPC ports.
4) it is difficult to run midas in the presence of firewalls (midas programs listen on random 
network ports - cannot be easily added to firewall rules)

There is a new git branch "feature/rpcsecurity" where I am addressing some of these 
problems:

1) UDP sockets are only used for internal communications (hotlinks & etc) within one 
machine, so they should be bound to the localhost address and become invisible to external 
machines. This change breaks binary compatibility from old clients - they are have to be 
relinked with the new midas library or hotlinks & etc will stop working. If some clients cannot 
be rebuild (I have one like this), I am preserving the old way by checking for a special file in 
the experiment directory (same place as ODB.SHM). (done)

2) if one runs on a single machine, does not use the mserver and does not have clients 
running on other machines, then all the RPC ports can be bound to localhost. (this kills the 
MacOS popups about "odbedit wants to connect to the Internet"). (partially done)

This (2) will become the new default - out of the box, midas will not listen to any external 
network connections - making it very secure.

To use the mserver, one will have to change the ODB setting "/Experiment/Security/Enable 
external RPC connections" and restart all midas programs (I am looking for a better name for 
this odb setting).

3) the out-of-the-box default access control list for RPC connections will be set to 
"localhost", which will reject all external connections, even when they are enabled by (2). One 
will be required to enter the names of all machines that will run midas clients in 
"/Experiment/Security/Rpc hosts". (already implemented in main midas, but default access 
control list is empty meaning everybody is permitted)

4) the mserver will be required to attach to some experiment and will use this same access 
control list to restrict access to the main mserver listener port. Right now the mserver listens 
on this port without attaching to any experiment and accepts the access control list via 
command line arguments. I think after this change a single mserver will still be able to service 
multiple experiments (TBD).

5) I am adding an option to fix TCP port numbers for MIDAS programs via 
"/Experiment/Security/Rpc ports/fename = (int)5555". Once a remote frontend is bound to a 
fixed port, appropriate openings can be made in the firewall, etc. Default port number value 
will be 0 meaning "use random port", same as now.

One problem remains with initial connecting to the mserver. The client connects to the main 
mserver listener port (easy to firewall), but then the mserver connects back to the client - this 
reverse connection is difficult to firewall and this handshaking is difficult to fix in the midas 
sources. It will probably remain unresolved for now.

K.O.

There is a number of problems with network security in midas. (as separate from web/http/https security).

1) too many network sockets are unnecessarily bound to the external network interface instead of localhost (UDP ports are already bound to localhost on MacOS).
2) by default the RPC ports of each midas program accept connections and RPC commands from anywhere in the world (an access control list is already implemented via /Experiment/Security/Rpc Hosts, but not active by default)
3) mserver also has an access control list but it is not integrated with the access control list for the RPC ports.
4) it is difficult to run midas in the presence of firewalls (midas programs listen on random network ports - cannot be easily added to firewall rules)

There is a new git branch "feature/rpcsecurity" where I am addressing some of these problems:

1) UDP sockets are only used for internal communications (hotlinks & etc) within one machine, so they should be bound to the localhost address and become invisible to external machines. This change breaks binary compatibility from old clients - they are have to be relinked with the new midas library or hotlinks & etc will stop working. If some clients cannot be rebuild (I have one like this), I am preserving the old way by checking for a special file in the experiment directory (same place as ODB.SHM). (done)

2) if one runs on a single machine, does not use the mserver and does not have clients running on other machines, then all the RPC ports can be bound to localhost. (this kills the MacOS popups about "odbedit wants to connect to the Internet"). (partially done)

This (2) will become the new default - out of the box, midas will not listen to any external network connections - making it very secure.

To use the mserver, one will have to change the ODB setting "/Experiment/Security/Enable external RPC connections" and restart all midas programs (I am looking for a better name for this odb setting).

3) the out-of-the-box default access control list for RPC connections will be set to "localhost", which will reject all external connections, even when they are enabled by (2). One will be required to enter the names of all machines that will run midas clients in "/Experiment/Security/Rpc hosts". (already implemented in main midas, but default access control list is empty meaning everybody is permitted)

4) the mserver will be required to attach to some experiment and will use this same access control list to restrict access to the main mserver listener port. Right now the mserver listens on this port without attaching to any experiment and accepts the access control list via command line arguments. I think after this change a single mserver will still be able to service multiple experiments (TBD).

5) I am adding an option to fix TCP port numbers for MIDAS programs via "/Experiment/Security/Rpc ports/fename = (int)5555". Once a remote frontend is bound to a fixed port, appropriate openings can be made in the firewall, etc. Default port number value will be 0 meaning "use random port", same as now.

One problem remains with initial connecting to the mserver. The client connects to the main mserver listener port (easy to firewall), but then the mserver connects back to the client - this reverse connection is difficult to firewall and this handshaking is difficult to fix in the midas sources. It will probably remain unresolved for now.

K.O.

The define for MAX_EVENT_SIZE was removed from midas.h.

Replacing it is DEFAULT_MAX_EVENT_SIZE set to 4 MiBytes and DEFAULT_BUFFER_SIZE 
set to 32 MiBytes.

For a long time now MIDAS does not have hardcoded maximum event size and buffer size 
and this change merely renames the define to reflect it's current function.

The actual maximum event size is set by ODB /Experiment/MAX_EVENT_SIZE.

The actual event buffer sizes are set by ODB "/Experiment/Buffer sizes/SYSTEM" & co

K.O.

> A set of improvements to mlogger is in:
> The current test version implements the following selections of "compression":
> 
> 80 - ROOT output through the new driver (use rmlogger executable)
> ...

Additional output modes through the new output drivers:

81 - FTP output
82 - FTP output with LZ4 compression

The format of the "Channels/xxx/Settings/Filename" for FTP output is like this:
"/localhost, 5555, ftpuser, ftppwd, ., run%05dsub%05d.mid"

- the leading slash is required (for now)
- localhost is the FTP server hostname
- 5555 is the FTP server port number
- ftpuser and ftppwd are the FTP login. password is stored and transmitted in clear text for extra security
- "." is the output directory on the FTP server
- the rest is the file name in the usual format.

For testing this driver, I run the ftp server like this:

# vsftpd -olisten=YES -obackground=no -olisten_port=5555 -olisten_address=127.0.0.1 -oport_promiscuous=yes -oconnect_from_port_20=no -oftp_data_port=6666

K.O.

> A set of improvements to mlogger is in:
> b) test version of LZ4 high speed compression, support for bzip2 and pbzip2

rootana TMidasFile now supports reading .mid.lz4 compressed files via pipe through the "lz4" utility ("yum install lz4", "apt-get install liblz4-tool").

In MIDAS, the lz4 libraries are included with the MIDAS distribution, we are considering the same for ROOTANA.

(Support for reading mid.bz2 files via pipe through the bzip2 utility existed for a very long time).

https://bitbucket.org/tmidas/rootana/commits/e06bb7296a466b4178c7768bbc2470be361b2c72

K.O.

> > ROOT support in MIDAS is being reworked:
> >
> > c) Makefile inconsistency between use of ROOTSYS and use of root-config has been identified,
> 
> MIDAS Makefile was corrected to use root-config exclusively to find and use ROOT. This makes us more consistent
> with the ROOT-recommended use of the thisroot.{sh,csh} scripts.
> 

The updated ROOT instructions on DAQwiki
https://www.triumf.info/wiki/DAQwiki/index.php/ROOT
now explain how to use "thisroot" to select the right version of the package.

The preliminary version of the .bashrc blurb looks like this
(a couple of flaws:
1) identification of CentOS7 is incomplete - please send me a patch
2) there should be a check for root-config already in the PATH, as on Ubuntu, the ROOT package may be installed in /usr and root-
config may be already in the path - please send me patch).

if [ `uname -i` == "i386" ]; then 
    . /daq/daqshare/olchansk/root/root_v5.34.01_SL62_32/bin/thisroot.sh 
    true 
elif [ `lsb_release -r -s` == "7.1.1503" ]; then 
    #. /daq/daqshare/olchansk/root/root_v5.34.32_SL66_64/bin/thisroot.sh 
    true 
else 
     . /daq/daqshare/olchansk/root/root_v5.34.32_SL66_64/bin/thisroot.sh 
     true 
fi 

K.O.

> ROOT support in MIDAS is being reworked:
>
> c) Makefile inconsistency between use of ROOTSYS and use of root-config has been identified,

MIDAS Makefile was corrected to use root-config exclusively to find and use ROOT. This makes us more consistent
with the ROOT-recommended use of the thisroot.{sh,csh} scripts.

In other words, if root-config is in the PATH, ROOT support will be enabled, rmlogger and rmana.o will be built.

To explicitly disable ROOT, say "make NO_ROOT=1"

K.O.

MIDAS does not seem to be consistent (or at least convenient) with how it
handles booleans in AJAX functions.

When you request an ODB value that is a boolean with AJAX call like

http://neut14.triumf.ca:8081/?cmd=jcopy&odb=/Equipment/DCRC/Common/Hidden&format=json-nokeys

then you get

{ "Hidden/last_written" : 1437065425, "Hidden" : false }

This seems correct, since the JSON convention has booleans encoded as true/false.

But this convention does not work when trying to set the boolean value. For instance

http://neut14.triumf.ca:8081/?cmd=jset&odb=/Equipment/DCRC/Common/Hidden&format=json-nokeys&value=true

does not set the variable to true. To make this work you need to use the
characters y/n

http://neut14.triumf.ca:8081/?cmd=jset&odb=/Equipment/DCRC/Common/Hidden&format=json-nokeys&value=y

I tested this with ajax/jset, but the same problem seems to occur when using the
javascript function ODBSet. The documentation doesn't say what sort of encoding
to use when using these functions, so I guess the idea is that these functions
use MIDAS encoding for booleans. But it seems to me that it would be more
convenient if jset/ODBSet allowed the option to use json/javascript encoding for
boolean values; or at least had that as a format option for jset/ODBSet.  That
way my javascript could look like

var mybool = true;
URI_command =
"?cmd=jset&odb=/Equipment/DCRC/Common/Hidden&format=json-nokeys&value=" + mybool;

instead of

var mybool = true;
URI_command = ""
if(mybool){
  URI_command =
"?cmd=jset&odb=/Equipment/DCRC/Common/Hidden&format=json-nokeys&value=y";
else
  URI_command =
"?cmd=jset&odb=/Equipment/DCRC/Common/Hidden&format=json-nokeys&value=n";


__________________________________________________________
Cross-posting from bitbucket issue tracker:

https://bitbucket.org/tmidas/midas/issues/29/jset-odbset-using-true-false-for-booleans

Latest C/C++ compilers (MacOS 10.10, GCC on RHEL7 and Ubuntu) generate a large number of new 
warnings about unused variables, unused functions, dead code, failure to check return values of system 
calls, etc.

Some of these warnings catch real bugs so we do not want to turn them off.

Most of these warnings have been cleaned out in the latest MIDAS code. On MacOS and RHEL6 Linux MIDA 
S compiles without any warnings. On RHEL7 and Ubuntu Linux there are some warnings from a few 
problematic files, history.c being the worst (it will be eventually cleaned out).

K.O.

ROOT support in MIDAS is being reworked:

a) ROOT support moved from midas.h to rmidas.h
b) default mlogger is built without ROOT support, use rmlogger if you need ROOT output
c) Makefile inconsistency between use of ROOTSYS and use of root-config has been identified, but not yet 
fixed. the plan is to use root-config to detect and use the ROOT package.
d) cross compilation will not support ROOT (same as now. "make linux32", "make linux64", "make 
linuxarm" disable most optional packages. To build full featured midas with ROOT & etc please compile 
natively on the ARM machine).
e) histogram servers in MIDAS and ROOTANA will be switched to use the new ROOT Web server classes 
(based on "civet", a fork of the mongoose web server).

K.O.

> > mhttpd uses the latest release of mongoose 4.2

mhttpd is now explicitly linked with OpenSSL to provide secure https connections via the mongoose web server.

a) google chrome reports "Your connection to ... is encrypted with modern cryptography." via TLS 1.2 and ECDHE ciphers
b) we believe there are no Linux systems that require running mhttpd and lack OpenSSL, but building mhttpd without OpenSSL is supported, see the cross 
compilation section in the Makefile.
c) MacOS comes with a very old version of OpenSSL. mhttpd will build, https will work, but with a complaint about "obsolete cryptography". Please install an up-to-
date OpenSSL package via macports.
d) security of OpenSSL itself is quite problematic, please keep an eye open on OpenSSL security advisories, update OpenSSL and restart/rebuild mhttpd promptly. I 
expect the mongoose project to eventually switch from OpenSSL to one of the new-generation TLS libraries, such as PolarSSL (embed_tls) and we will follow their 
lead.

K.O.