Re: Improving read/write/close system call reliability when used with pthreads

From: Fredrik Noring
Date: Mon Aug 13 2007 - 08:28:33 EST


David,

True. Even though there is a point in making the kernel detect and behave consistently in this case applications (often) end up with their own mess they cannot easily handle. A few more use cases would now work OK but probably not enough to make the improvement worthwhile.

Thanks,
Fredrik

13 aug 2007 kl. 05.14 skrev David Schwartz:
Since there's no atomic "unlock and read" function, any code that could ever
close a socket in one thread while another thread is blocked on read might
call close just before another thread blocks in read. Nothing stops another
thread from opening something, getting the same file descriptor, and then
allowing the thread to call "read" on the wrong file descriptor entirely.

Since this can never be made sane in general, I see little point in making
one variation of what can go wrong a bit saner. It is still irresponsible to
code like this.

DS




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