ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
size_t offset, size_t bytes,
bool do_send)
{
ssize_t ret;
unsigned si, ei; /* start and end indexes */
if (bytes == 0) {
/* Catch the do-nothing case early, as otherwise we will pass an
* empty iovec to sendmsg/recvmsg(), and not all implementations
* accept this.
*/
return 0;
}
/* Find the start position, skipping `offset' bytes:
* first, skip all full-sized vector elements, */
for (si = 0; si < iov_cnt && offset >= iov[si].iov_len; ++si) {
offset -= iov[si].iov_len;
}
if (offset) {
assert(si < iov_cnt);
/* second, skip `offset' bytes from the (now) first element,
* undo it on exit */
iov[si].iov_base += offset;
iov[si].iov_len -= offset;
}
/* Find the end position skipping `bytes' bytes: */
/* first, skip all full-sized elements */
for (ei = si; ei < iov_cnt && iov[ei].iov_len <= bytes; ++ei) {
bytes -= iov[ei].iov_len;
}
if (bytes) {
/* second, fixup the last element, and remember
* the length we've cut from the end of it in `bytes' */
size_t tail;
assert(ei < iov_cnt);
assert(iov[ei].iov_len > bytes);
tail = iov[ei].iov_len - bytes;
iov[ei].iov_len = bytes;
bytes = tail; /* bytes is now equal to the tail size */
++ei;
}
ret = do_send_recv(sockfd, iov + si, ei - si, do_send);
/* Undo the changes above */
if (offset) {
iov[si].iov_base -= offset;
iov[si].iov_len += offset;
}
if (bytes) {
iov[ei-1].iov_len += bytes;
}
return ret;
}
Test(fas_sep_gni_fmt_av_tbl, send_recv)
{
do_send_recv();
}
Test(fas_ep_str_fmt_av_tbl, send_recv)
{
do_send_recv();
}
Test(fas_sep_str_fmt_av_map, send_recv)
{
do_send_recv();
}
Test(fas_ep_gni_fmt_av_map, send_recv)
{
do_send_recv();
}
ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
size_t offset, size_t bytes,
bool do_send)
{
ssize_t total = 0;
ssize_t ret;
size_t orig_len, tail;
unsigned niov;
while (bytes > 0) {
/* Find the start position, skipping `offset' bytes:
* first, skip all full-sized vector elements, */
for (niov = 0; niov < iov_cnt && offset >= iov[niov].iov_len; ++niov) {
offset -= iov[niov].iov_len;
}
/* niov == iov_cnt would only be valid if bytes == 0, which
* we already ruled out in the loop condition. */
assert(niov < iov_cnt);
iov += niov;
iov_cnt -= niov;
if (offset) {
/* second, skip `offset' bytes from the (now) first element,
* undo it on exit */
iov[0].iov_base += offset;
iov[0].iov_len -= offset;
}
/* Find the end position skipping `bytes' bytes: */
/* first, skip all full-sized elements */
tail = bytes;
for (niov = 0; niov < iov_cnt && iov[niov].iov_len <= tail; ++niov) {
tail -= iov[niov].iov_len;
}
if (tail) {
/* second, fixup the last element, and remember the original
* length */
assert(niov < iov_cnt);
assert(iov[niov].iov_len > tail);
orig_len = iov[niov].iov_len;
iov[niov++].iov_len = tail;
ret = do_send_recv(sockfd, iov, niov, do_send);
/* Undo the changes above before checking for errors */
iov[niov-1].iov_len = orig_len;
} else {
ret = do_send_recv(sockfd, iov, niov, do_send);
}
if (offset) {
iov[0].iov_base -= offset;
iov[0].iov_len += offset;
}
if (ret < 0) {
assert(errno != EINTR);
if (errno == EAGAIN && total > 0) {
return total;
}
return -1;
}
if (ret == 0 && !do_send) {
/* recv returns 0 when the peer has performed an orderly
* shutdown. */
break;
}
/* Prepare for the next iteration */
offset += ret;
total += ret;
bytes -= ret;
}
return total;
}
