Sounds trivial. Either use mmap
[1] or a subset of System V IPC
[2], assuming you are running a kernel which supports these features. You could probably come up with a solution just by searching Google for five minutes.
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[1] - http://www.gnu.org/software/libc/manual/html_node/Memory_002dmapped-I_002fO.html
[2] - http://tldp.org/LDP/lpg/node21.html#SECTION00740000000000000000