changing mmap() permissions

[Kevin Buettner]

On Aug 20, 11:44am, Randy Kaelber wrote:

> I'm trying to implement a distributed shared memory system using network
> sockets and mmap().  A problem I have run into is that I want to protect
> segments of memory from being written to by a process.  While it's easy
> enough to mmap() a region read only, What I want to do is receive a
> chunk of data from a remote process, mmap() it to a specific address,
> and then make that block read-only, such that if a process tries to
> write it after I've copied it in, it will get a seg fault.  If I start
> read only, I cannot copy data to the region at all.

Take a look at mprotect().

Kevin