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2015-02-20map interruption of close by signal to success rather than EINPROGRESSRich Felker1-1/+1
commit 82dc1e2e783815e00a90cd3f681436a80d54a314 addressed the resolution of Austin Group issue 529, which requires close to leave the fd open when failing with EINTR, by returning the newly defined error code EINPROGRESS. this turns out to be a bad idea, though, since legacy applications not aware of the new specification are likely to interpret any error from close except EINTR as a hard failure.
2015-02-13overhaul aio implementation for correctnessRich Felker1-0/+8
previously, aio operations were not tracked by file descriptor; each operation was completely independent. this resulted in non-conforming behavior for non-seekable/append-mode writes (which are required to be ordered) and made it impossible to implement aio_cancel, which in turn made closing file descriptors with outstanding aio operations unsafe. the new implementation is significantly heavier (roughly twice the size, and seems to be slightly slower) and presently aims mainly at correctness, not performance. most of the public interfaces have been moved into a single file, aio.c, because there is little benefit to be had from splitting them. whenever any aio functions are used, aio_cancel and the internal queue lifetime management and fd-to-queue mapping code must be linked, and these functions make up the bulk of the code size. the close function's interaction with aio is implemented with weak alias magic, to avoid pulling in heavy aio cancellation code in programs that don't use aio, and the expensive cancellation path (which includes signal blocking) is optimized out when there are no active aio queues.
2012-09-24fix handling of EINTR during close()Rich Felker1-1/+4
austin group interpretation for defect #529 (http://austingroupbugs.net/view.php?id=529) tightens the requirements on close such that, if it returns with EINTR, the file descriptor must not be closed. the linux kernel developers vehemently disagree with this, and will not change it. we catch and remap EINTR to EINPROGRESS, which the standard allows close() to return when the operation was not finished but the file descriptor has been closed.
2011-04-18remove bogus extra logic for close cancellabilityRich Felker1-3/+1
like all other syscalls, close should return to the caller if and only if it successfully performed its action. it is necessary that the application be able to determine whether the close succeeded.
2011-04-17overhaul pthread cancellationRich Felker1-3/+2
this patch improves the correctness, simplicity, and size of cancellation-related code. modulo any small errors, it should now be completely conformant, safe, and resource-leak free. the notion of entering and exiting cancellation-point context has been completely eliminated and replaced with alternative syscall assembly code for cancellable syscalls. the assembly is responsible for setting up execution context information (stack pointer and address of the syscall instruction) which the cancellation signal handler can use to determine whether the interrupted code was in a cancellable state. these changes eliminate race conditions in the previous generation of cancellation handling code (whereby a cancellation request received just prior to the syscall would not be processed, leaving the syscall to block, potentially indefinitely), and remedy an issue where non-cancellable syscalls made from signal handlers became cancellable if the signal handler interrupted a cancellation point. x86_64 asm is untested and may need a second try to get it right.
2011-03-20global cleanup to use the new syscall interfaceRich Felker1-1/+1
2011-02-12initial check-in, version 0.5.0v0.5.0Rich Felker1-0/+11