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2012-06-11rewrite iov_send_recv() and move it to iov.cMichael Tokarev1-6/+9
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>
2012-06-11export iov_send_recv() and use it in iov_send() and iov_recv()Michael Tokarev1-3/+7
Rename do_sendv_recvv() to iov_send_recv(), change its last arg (do_send) from int to bool, export it in iov.h, and made the two callers of it (iov_send() and iov_recv()) to be trivial #defines just adding 5th arg. iov_send_recv() will be used later. Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2012-06-11rename qemu_sendv to iov_send, change proto and move declarations to iov.hMichael Tokarev1-0/+18
Rename arguments and use size_t for sizes instead of int, from int qemu_sendv(int sockfd, struct iovec *iov, int len, int iov_offset) to ssize_t iov_send(int sockfd, struct iovec *iov, size_t offset, size_t bytes) The main motivation was to make it clear that length and offset are in _bytes_, not in iov elements: it was very confusing before, because all standard functions which deals with iovecs expects number of iovs, not bytes, even the fact that struct iovec has iov_len and iov_ prefix does not help. With "bytes" and "offset", especially since they're now size_t, it is much more explicit. Also change the return type to be ssize_t instead of int. This also changes it to match other iov-related functons, but not _quite_: there's still no argument indicating where iovec ends, ie, no iov_cnt parameter as used in iov_size() and friends. If will be added in subsequent patch/rewrite. All callers of qemu_sendv() and qemu_recvv() and related, like qemu_co_sendv() and qemu_co_recvv(), were checked to verify that it is safe to use unsigned datatype instead of int. Note that the order of arguments is changed to: offset and bytes (len and iov_offset) are swapped with each other. This is to make them consistent with very similar functions from qemu_iovec family, where offset always follows qiov, to mean the place in it to start from. Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2012-06-07rewrite iov_* functionsMichael Tokarev1-2/+10
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 Tokarev1-5/+37
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>
2011-08-04Add iov_clear()Gerd Hoffmann1-0/+2
Fill the spefified area with zeros. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2011-08-04Add iov_hexdump()Gerd Hoffmann1-0/+2
Useful for debugging purposes. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2011-07-18iov: Update parameter usage in iov_(to|from)_buf()Hannes Reinecke1-5/+5
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/+19
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>