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Posted to users@httpd.apache.org by ku...@mail.com on 2005/05/30 08:01:47 UTC

[users@httpd] httpd forks & handling duplicate file descriptor

Hi 

Need help in solving the httpd fork and file descriptor issue -

scenario:
Iam doing a sendmsg(fd,..) followed by recv(fd,...) indirectly in my php file.
i.e, iam calling socket API's which are warppers for sendmsg() and recv() 
by including them in my php file.
There are multile such php files which call sendmsg()and recv() for different functionality.
I don't have much control over 'fd' and they are supposed to be generated in ususal incremental manner.
The sendmsg() and recv() are hence intended to be run 'atomic' to avoid one recv() actually 
receiving the reply for sendmsg() of a wrong pair. 

My issue: 
since http does a load sharing and creates forks for httpd (ps -ef |grep httpd) at any given point of time 
i noticed that the same file desciptors are being used across the different php files (used strace for this).
This is causing some recv()s to actually receive the reply for sendmsg() of a wrong pair.

better solutions please..?:
1) I could check if the recv() data matches the sendmsg() request by comparing some data.
   Not a good solution since this is not the root cause's solution. 

2) I tried using php semaphores (sem_get/sem_aquire/sem_release) around all the send/recv pairs.
   However this still didn't solve my problem.
   [ is httpd fork ignoring a semaphore region and still forking and 
    and handling a different php when a recv() is already waiting ???]

Pls do let me know a better way of handling this issue.

Nb: newbie and first post. i did not find any luck in the httd archives as well. 
Regards
Noor

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