Re: IocLogInit

[Andrew Johnson <anj@aps.anl.gov>]

Gasper Jansa wrote:
> I have noticed that if I set EPICS_IOC_LOG_INET to lets say 10.17.10.241 and if
> I am on a network from which this IP can not be reached cpu goes to 100% and
> stays there if I start logging with command iocLogInit from startup script. I
> also get "Network unreachable" error.
>
> I am experiencing this on a debian and scientific linux.

After a little investigation I can replicate your problem on FC4, and I 
see that this behaviour of the log client is different if you have a 
default route set on the machine (which is probably how most developer 
linux workstations are configured).

With no default route (no line for the destination 0.0.0.0 in the output 
from 'netstat -nr') I get your behaviour:

> epics> epicsEnvSet EPICS_IOC_LOG_INET 192.168.123.45
> epics> iocLogInit
> log client: unable to connect to "192.168.123.45:7004" because 101="Network is unreachable"
> log client: unable to connect to "192.168.123.45:7004" for 2.0 seconds
> epics> iocLogShow
> log client: disconnected from log server at "192.168.123.45:7004"

The CPU usage on the machine then pegs at 100%.

However, with a default route installed (a destination of 0.0.0.0 listed 
in the output from 'netstat -nr') I get this instead:

> epics> epicsEnvSet EPICS_IOC_LOG_INET 192.168.123.45
> epics> iocLogInit
> log client: unable to connect to "192.168.123.45:7004" for 2.0 seconds
> epics> iocLogShow
> log client: disconnected from log server at "192.168.123.45:7004"

After a while I also get this message:

> log client: unable to connect to "192.168.123.45:7004" because 110="Connection timed out"

The machine CPU usage remains normal in this case.

I would therefore recommend that you set a default route on your IOC 
machine as a workaround until we get a fix into Base.

The iocLogShow command I used above is not callable from the iocsh in 
any released version of Base; I just added the relevent iocsh table 
entries that make it callable and committed the changes to CVS.


Do any of the other EPICS core developers claim ownership of the 
src/libCom/logClient/logClient.c code, which is where the problem lies? 
 The 101 value above would appear to be ENETUNREACH which is not 
mentioned in any osdSock.h file and not expected by the code in 
logClientConnect().  I might expect similar kinds of problems to appear 
if someone mentions an unreachable IP address in any of the network 
configuration settings such as EPICS_CA_ADDR_LIST, but I haven't tried 
them to confirm that.

- Andrew
--
There is considerable overlap between the intelligence of the smartest
bears and the dumbest tourists -- Yosemite National Park Ranger