On 12/08/2010 06:45 PM, John P. Rouillard wrote: > > In message<4cffa586.70...@fleetboard.com>, > M Haris Farooque writes: >> I have another question related to Named Pipe. >> I have made a "/usr/local/etc/SEC_Log_Pipe " and hang it with SEC so=20 >> that SEC can read input text from it; >> >> *cmd1*: /perl -w /usr/local/sbin/sec.pl --conf=3Dxxx.cfg --conf=3Dyyy.cfg= >> =20 >> --conf=3Dzzz.cfg -input=3D/usr/local/etc/SEC_Log_Pipe -intevents/ >> >> I need to log some information also in a log file upon successful=20 >> execution of one of my defined rule and i wanted to use the same pipe=20 >> for writing it. >> [...] >> Is there a good way to handle read/write operations through named pipe? >> Thanks in advance, > > The result of using multiple readers on a fifo/named pipe differes > from OS to OS, but IIRC only one process will sucessfully read from > the pipe in most cases. The fifo doesn't duplicate any data. Once the > data is read by a process it is gone. > > I would just use two seperate fifo/named pipes. > > Also note that writing to a fifo/named pipe can block if there is no > reader so you have to be careful when using the write action to > directly write to a fifo so that it doesn't hang the SEC process.
John has made an important point here -- the lack of reader stalls the entire SEC process. And if one opens fifo in nonblocking mode, data loss might occur. Since the idea seems to be write some lines into a separate file, I'd recommend to do it from the SEC rule with 'write' action. kind regards, risto > > -- > -- rouilj > John Rouillard > =========================================================================== > My employers don't acknowledge my existence much less my opinions. > > > > > > > > > > > > ------------------------------------------------------------------------------ > This SF Dev2Dev email is sponsored by: > > WikiLeaks The End of the Free Internet > http://p.sf.net/sfu/therealnews-com > _______________________________________________ > Simple-evcorr-users mailing list > Simple-evcorr-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/simple-evcorr-users > ------------------------------------------------------------------------------ This SF Dev2Dev email is sponsored by: WikiLeaks The End of the Free Internet http://p.sf.net/sfu/therealnews-com _______________________________________________ Simple-evcorr-users mailing list Simple-evcorr-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/simple-evcorr-users
