49 lines
1.5 KiB
Text
49 lines
1.5 KiB
Text
|
From: Nico Schottelius
|
||
|
|
Subject: Unix IPC, socket/AF_UNIX; bind on r/o devices?
|
||
|
|
Date: 09 May 2005 09:51:27 GMT
|
||
|
|
To: comp.unix.programmer
|
||
|
|
|
||
|
|
Hello!
|
||
|
|
|
||
|
|
Situation:
|
||
|
|
- everything mounted readonly (as when starting the system)
|
||
|
|
- one process with n children, which may have n children (recursive)
|
||
|
|
- all the children and children of children should be able to talk to the
|
||
|
|
first parent
|
||
|
|
|
||
|
|
Problem:
|
||
|
|
- Using bind() will fail, because
|
||
|
|
a) socket cannot created
|
||
|
|
b) the existing socket cannot be reused
|
||
|
|
|
||
|
|
Other possibilities not working:
|
||
|
|
- shared memory is not an option, as one need
|
||
|
|
-lrt, which needs -lpthread, which is problematic to link statically
|
||
|
|
|
||
|
|
- pipes: handling the pipes from parent to child of child of child
|
||
|
|
would be hard to program
|
||
|
|
|
||
|
|
- socketpair: should be the same problematic as it's with pipes
|
||
|
|
|
||
|
|
- fifos: one would have to create the fifos before and two fifos
|
||
|
|
for each child; possible, but very unelegant; and one would have
|
||
|
|
to memorize, which child is connected to which fifo; again possible,
|
||
|
|
but somehow unelegant
|
||
|
|
|
||
|
|
- signaling: one could implement communication with some kind of
|
||
|
|
morse code with signals, but that won't be a good solution
|
||
|
|
|
||
|
|
Questions:
|
||
|
|
- Is there any way, case b) (socket already existing) can be solved in
|
||
|
|
a way that I tell bind() to use an existing socket?
|
||
|
|
- What would be the best solution to talk bidirectional to clients
|
||
|
|
in this scenario?
|
||
|
|
|
||
|
|
I appreciate any hint, as I really like the socket mechanism and would
|
||
|
|
like to keep it.
|
||
|
|
|
||
|
|
|
||
|
|
Thanks in advance,
|
||
|
|
|
||
|
|
Nico
|