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2012-08-15iov_send_recv(): Handle zero bytes case even if OS does notPeter Maydell1-0/+7
POSIX allows sendmsg() and recvmsg() to fail EMSGSIZE if passed a zero msg.msg_iovlen (in particular the MacOS X implementation will do this). Handle the case where iov_send_recv() is passed a zero byte count explicitly, to avoid accidentally depending on the OS to treat zero msg_iovlen as a no-op. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Acked-by: Michael Tokarev <mjt@tls.msk.ru> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2012-07-11iov: Fix do_send_recv() for MinGW (also fixes a build breakage)Stefan Weil1-5/+6
Commit 25e5e4c7 broke compilation for non POSIX hosts (e.g. MinGW) because it partially replaced "ret" by "count". It also changed the handling of EINTR in a wrong way. The patch restores the old code for these two changes. Signed-off-by: Stefan Weil <sw@weilnetz.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-06-11rewrite iov_send_recv() and move it to iov.cMichael Tokarev1-0/+103
Make it much more understandable, add a missing iov_cnt argument (number of iovs in the iov), and add comments to it. The new implementation has been extensively tested by splitting a large buffer into many small randomly-sized chunks, sending it over socket to another, slow process and verifying the receiving data is the same. Also add a unit test for iov_send_recv(), sending/ receiving data between two processes over a socketpair using random vectors and random sizes. Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2012-06-07rewrite iov_* functionsMichael Tokarev1-52/+39
This changes implementations of all iov_* functions, completing the previous step. All iov_* functions now ensure that this offset argument is within the iovec (using assertion), but lets to specify `bytes' value larger than actual length of the iovec - in this case they stops at the actual end of iovec. It is also suggested to use convinient `-1' value as `bytes' to mean just this -- "up to the end". There's one very minor semantic change here: new requiriment is that `offset' points to inside of iovec. This is checked just at the end of functions (assert()), it does not actually need to be enforced, but using any of these functions with offset pointing past the end of iovec is wrong anyway. Note: the new code in iov.c uses arithmetic with void pointers. I thought this is not supported everywhere and is a GCC extension (indeed, the C standard does not define void arithmetic). However, the original code already use void arith in iov_from_buf() function: (memcpy(..., buf + buf_off,...) which apparently works well so far (it is this way in qemu 1.0). So I left it this way and used it in other places. While at it, add a unit-test file test-iov.c, to check various corner cases with iov_from_buf(), iov_to_buf() and iov_memset(). Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2012-06-07change iov_* function prototypes to be more appropriateMichael Tokarev1-7/+7
Reorder arguments to be more natural, readable and consistent with other iov_* functions, and change argument names, from: iov_from_buf(iov, iov_cnt, buf, iov_off, size) to iov_from_buf(iov, iov_cnt, offset, buf, bytes) The result becomes natural English: copy data to this `iov' vector with `iov_cnt' elements starting at byte offset `offset' from memory buffer `buf', processing `bytes' bytes max. (Try to read the original prototype this way). Also change iov_clear() to more general iov_memset() (it uses memset() internally anyway). While at it, add comments to the header file describing what the routines actually does. The patch only renames argumens in the header, but keeps old names in the implementation. The next patch will touch actual code to match. Now, it might look wrong to pay so much attention to so small things. But we've so many badly designed interfaces already so the whole thing becomes rather confusing or error prone. One example of this is previous commit and small discussion which emerged from it, with an outcome that the utility functions like these aren't well-understdandable, leading to strange usage cases. That's why I paid quite some attention to this set of functions and a few others in subsequent patches. Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2012-01-13prepare for future GPLv2+ relicensingPaolo Bonzini1-0/+3
All files under GPLv2 will get GPLv2+ changes starting tomorrow. event_notifier.c and exec-obsolete.h were only ever touched by Red Hat employees and can be relicensed now. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-08-04Add iov_clear()Gerd Hoffmann1-0/+23
Fill the spefified area with zeros. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2011-08-04Add iov_hexdump()Gerd Hoffmann1-0/+31
Useful for debugging purposes. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2011-07-18iov: Update parameter usage in iov_(to|from)_buf()Hannes Reinecke1-22/+27
iov_to_buf() has an 'offset' parameter, iov_from_buf() hasn't. This patch adds the missing parameter to iov_from_buf(). It also renames the 'offset' parameter to 'iov_off' to emphasize it's the offset into the iovec and not the buffer. Signed-off-by: Hannes Reinecke <hare@suse.de> Acked-by: Alexander Graf <agraf@suse.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-10iov: Move from hw/ to topdirAmit Shah1-0/+70
The iov functions can be useful to other code as well. Signed-off-by: Amit Shah <amit.shah@redhat.com> CC: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>