#define EXPCVADC_COMMON_STR(_name) char *_name[] = {\
"[.]",\
...

#define EXPCVADC_COMMON_STR(_name) const char *_name[] = {\
"[.]",\
...

char *s = "whatever";
...
strcpy(s, "Hello, this is a string longer than the initial one.");

status = db_create_record(hDB, 0, set_str, strcomb(expcvadc_settings_str));

cvadcfe.c: In function ‘frontend_init’:
cvadcfe.c:144: warning: passing argument 1 of ‘strcomb’ from incompatible pointer type

Hi,
I'm new to both Linux and Midas and having trouble installing the programme - 
the install file suggeats that I should have a directory:

midas/unix

but this doesn't appear.

Also, when running the "make" for the library (step 3 of the installation), I 
don't see the directory "zlib.a", but there is a "libz.a" and I note the 
original .tar file has no libz.a file in it. Is this a typo on the 
installation?
The terminal window at this point displays:

undefined reference to `errno'
make: ***[example] Error 1

Further help will no doubt be required as I've used windows throughout my 
research and now looking to learn how to use linux. Any help greatly 
appreciated. Thanks!

I committed an updated lazylogger with updated documentation. The new version supports subruns and 
can save to external storage arbitrary files (i.e. odb dump files). It also moves most book keeping out of 
odb to permit handling more files on bigger storage disks.

Example lazylogger scripts for castor (CERN) and dcache (TRIUMF) are in the directory "utils".

The lazylogger documentation was updated to remove obsolete information and to describe the new 
functions. As usual "make dox; cd doxfiles/html; firefox index.html" or see my copy at:

http://ladd00.triumf.ca/~olchansk/midas/Utilities.html#lazylogger_task

svn rev 4615, 4616.
K.O.

Though ended with ".c", "lazylogger.c" has to be build with C++ compiler. I have 
to modify my CMakeLists.txt. 
Please see the attachment if you need it. It works with svn-r4616.

Dear All,

I want to run two frontend programs (one for trigger and one for slow control)
concurrently on the same computer, but I failed. The second frontend said: 

Semaphore already present
 There is another process using the semaphore.
 Or a process using the semaphore exited abnormally.
 In That case try to manually release the semaphore with:
   ipcrm sem XXX.

The two frontends are connected to the same experiment. Is there any way I can
overcome this problem?

Thanks!

Jimmy

> #define EXPCVADC_COMMON_STR(_name) const char *_name[] = {\
> "[.]",\
>...

Ok, I changed that in odb.c rev. 4620, should be fine now.

odb.c rev 4622 fixes ODB corruption by db_connect_database() if client_name is
too long. Also fixed is potential ODB corruption by too long key names in
db_create_key(). Problem kindly reported by Tim Nichols of T2K/ND280 experiment.
K.O.

> odb.c rev 4622 fixes ODB corruption by db_connect_database() if client_name is
> too long. Also fixed is potential ODB corruption by too long key names in
> db_create_key(). Problem kindly reported by Tim Nichols of T2K/ND280 experiment.


Related bug fix - db_connect_database() should not permit client names that contain
the slash (/) character. Names like "aaa/bbb" create entries /Programs/aaa/bbb (aaa
is a subdirectory) and names like "../aaa" create entries in the ODB root directory.

svn rev 4623.
K.O.

> When using remote midas clients with mserver, you may have noticed the zero-size .RPC.SHM files 
> these clients create in the directory where you run them.

Well, RPC.SHM bites. Please reread the parent message for full details, but in the nutshell, it is a global
semaphore that permits only one midas rpc client to talk to midas at a time (it was intended for local
locking between threads inside one midas application).

I have about 10 remote midas frontends started by ssh all in the same directory, so they all share the same
.RPC.SHM semaphore and do not live through the night - die from ODB timeouts because of RPC semaphore contention.

In a test version of MIDAS, I disabled the RPC.SHM semaphore, and now my clients live through the night, very
good.

Long term, we should fix this by using application-local mutexes (i.e. pthread_mutex, also works on MacOS, do
Windows have pthreads yet?).

This will also cleanup some of the ODB locking, which currently confuses pid's, tid's etc and is completely
broken on MacOS because some of these values are 64-bit and do not fit into the 32-bit data fields in MIDAS
shared memories.

Short term, I can add a flag for enabling and disabling the RPC semaphore from the user application: enabled
by default, but user can disable it if they do not use threads.

Alternatively, I can disable it by default, then enable it automatically if multiple threads are detected or
if ss_thread_create() is called.

Could also make it an environment variable.

Any preferences?

K.O.

Please be aware of mlogger.c update rev 4566 on Sept 23rd 2009, when Stefan
fixed a buglet in the subrun file size computations. Before this fix, the first
subrun could be of a short length. If you use subruns, please update your
mlogger to at least rev 4566 (or newer, Stefan added the run and subrun time
limits just recently).
K.O.

We were debugging a strange problem in the event builder, where out of 14
fragments, two fragments were always getting serial number mismatches and the
serial numbers were not sequentially increasing (the other 12 fragments were
just fine).

Then we noticed in the event builder debug output that these 2 fragments were
getting assigned the same buffer handle number, despite having different names -
BUF09 and BUFTPC.

Then we looked at "ipcs", counted the buffers, and there are only 13 buffers for
14 frontends.

Aha, we went, maybe we have unlucky buffer names, renamed BUFTPC to BUFAAA and
everything started to work just fine.

It turns out that the MIDAS ss_shm_open() function uses "ftok" to convert buffer
names to SystemV shared memory keys. This "ftok" function promises to create
unique keys, but I guess, just not today.

Using a short test program, I confirmed that indeed we have unlucky buffer names
and ftok() returns duplicate keys, see below.

Apparently ftok() uses the low 16 bits of the file inode number, but in our
case, the files are NFS mounted and inode numbers are faked inside NFS. When I
run my test program on a different computer, I get non-duplicate keys. So I
guess we are double unlucky.

Test program:

#include <stdio.h>
#include <sys/types.h>
#include <sys/ipc.h>

int main(int argc, char* argv[])
{
  //key_t ftok(const char *pathname, int proj_id);
  
  int k1 = ftok("/home/t2kdaq/midas/nd280/backend/.BUF09.SHM", 'M');
  int k2 = ftok("/home/t2kdaq/midas/nd280/backend/.BUFTPC.SHM", 'M');
  int k3 = ftok("/home/t2kdaq/midas/nd280/backend/.BUFFGD.SHM", 'M');

  printf("key1: 0x%08x, key2: 0x%08x, key3: 0x%08x\n", k1, k2, k3);
  return 0;
}

[t2kfgd@t2knd280logger ~/xxx]$ g++ -o ftok -Wall ftok.cxx
[t2kfgd@t2knd280logger ~/xxx]$ ./ftok
key1: 0x4d138154, key2: 0x4d138154, key3: 0x4d138152

Also:

[t2kfgd@t2knd280logger ~/xxx]$ ls -li ...
14385492 -rw-r--r-- 1 t2kdaq t2kdaq  8405052 Nov 24 17:42
/home/t2kdaq/midas/nd280/backend/.BUF09.SHM
36077906 -rw-r--r-- 1 t2kdaq t2kdaq 67125308 Nov 26 10:19
/home/t2kdaq/midas/nd280/backend/.BUFFGD.SHM
36077908 -rw-r--r-- 1 t2kdaq t2kdaq  8405052 Nov 25 15:53
/home/t2kdaq/midas/nd280/backend/.BUFTPC.SHM

(hint: print the inode numbers in hex and compare to shm keys printed by the
program)

K.O.

By request from Renee, I increased the MIDAS BANKLIST_MAX from 64 to 1024 and
after fixing a few buglets where YB_BANKLIST_MAX is used instead of (now bigger)
BANKLIST_MAX, I can do a full dump of ND280 FGD events (96 banks).

I also noticed that "mdump -b BANK" did not work, it turns out that it could not
handle 32bit-banks at all. This is now fixed, too.

svn rev 4624
K.O.

I notice that "mserver -s" (a non-default mode of operation) does not work right
- if I connect odbedit for the first time, all is okey, if I connect the second
time, mserver crashes - because after the first connection closed,
rpc_deregister_functions() was called, rpc_list is deleted and causes a crash
later on. Because everybody uses the default "mserver -m" mode, I am not sure
how important it is to fix this.
K.O.

mserver update svn rev 4625 fixes an anomaly in the MIDAS RPC network code where
in some network configurations MIDAS mserver connections work, but some RPC
transactions, such as starting and stopping runs, do not (use the wrong network
names or are routed over the wrong network).

The problem is a possible discrepancy between network addresses used to
establish the mserver connection and the value of "/System/Clients/xxx/Host"
which is ultimately set to the value of "hostname" of the remote client. This
ODB setting is then used to establish additional network connections, for
example to start or stop runs.

Use the client "hostname" setting works well for standard configurations, when
there is only one network interface in the machine, with only one IP address,
and with "hostname" set to the value that this IP address resolves to using DNS.

However, if there are private networks, multiple network interfaces, or multiple
network routes between machines, "/System/Clients/xxx/Host" may become set to an
undesirable value resulting in asymmetrical network routing or complete failure
to establish RPC connections.

Svn rev 4625 updates mserver.c to automatically set "/System/clients/xxx/Host"
to the same network name as was used to establish the original mserver connection.

As always with networking, any fix always breaks something somewhere for
somebody, in which case the old behavior can be restored by "setenv
MIDAS_MSERVER_DO_NOT_USE_CALLBACK_ADDR 1" before starting mserver.

The specific problem fixed by this change is when the MIDAS client and server
are on machines connected by 2 separate networks ("client.triumf.ca" and
"client.daq"; "server.triumf.ca" and "server.daq"). The ".triumf.ca" network
carries the normal SSH, NFS, etc traffic, and the ".daq" network carries MIDAS
data traffic.

The client would use the "server.daq" name to connect to the server and this
traffic would go over the data network (good).

However, previously, the client "/System/Clients/xxx/Host" would be set to
"client.triumf.ca" and any reverse connections (i.e. RPC to start/stop runs)
would go over the normal ".triumf.ca" network (bad).

With this modification, mserver will set "/System/Clients/xxx/Host" to
"client.daq" (the IP address of the interface on the ".daq" network) and all
reverse connections would also go over the ".daq" network (good).

P.S. This modification definitely works only for the default "mserver -m" mode,
but I do not think this is a problem as using "-s" and "-t" modes is not
recommended, and the "-s" mode is definitely broken (see my previous message).

svn rev 4625
K.O.

> I notice that "mserver -s" (a non-default mode of operation) does not work right
> - if I connect odbedit for the first time, all is okey, if I connect the second
> time, mserver crashes - because after the first connection closed,
> rpc_deregister_functions() was called, rpc_list is deleted and causes a crash
> later on. Because everybody uses the default "mserver -m" mode, I am not sure
> how important it is to fix this.
> K.O.

"mserver -s" is there for historical reasons and for debugging. I started originally 
with a single process server back in the 90's, and only afterwards developed the multi 
process scheme. The single process server now only works for one connection and then 
crashes, as you described. But it can be used for debugging any server connection, 
since you don't have to follow the creation of a subprocess with your debugger, and 
therefore it's much easier. But after the first connection has been closed, you have 
to restart that single server process. Maybe one could add some warning about that, or 
even fix it, but it's nowhere used in production mode.

> 
> "mserver -s" is there for historical reasons and for debugging.
>

I confirm that my modification also works for "mserver -s". I also added an assert() to the
place in midas.c were it eventually crashes, to make it more obvious for the next guys.

K.O.

> Dear All,
> 
> I want to run two frontend programs (one for trigger and one for slow control)
> concurrently on the same computer, but I failed. The second frontend said: 
> 
> Semaphore already present
>  There is another process using the semaphore.
>  Or a process using the semaphore exited abnormally.
>  In That case try to manually release the semaphore with:
>    ipcrm sem XXX.
> 
> The two frontends are connected to the same experiment. Is there any way I can
> overcome this problem?

That might be related to the RPC mutex, which gets created system wide now. I 
modified this in midas.c rev. 4628, so there will be one mutex per process. Can you 
try that temporary patch and tell me if it works for you?

The custom and alias links in the standard midas status page were shown as HTML 
links so far. If there are many links with names having spaces in their names, 
it's a bit hard to distinguish between them. Therefore, they are packed now into 
individual buttons (see attachment) starting from SVN revision 4633 on. This makes 
also the look more homogeneous. If there is any problem with that, please report.