With a pipe or other reasons, read/write may return less than the
requested bytes. This happens with the test-io-channel-command test on
Windows. glib spawn code uses a binary pipe of 4096 bytes, and the first
read returns that much (although more are requested), for some unclear
reason...
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <
20221006113657.
2656108-2-marcandre.lureau@redhat.com>
#ifndef CONFIG_IOVEC
-/* helper function for iov_send_recv() */
static ssize_t
readv_writev(int fd, const struct iovec *iov, int iov_cnt, bool do_write)
{
unsigned i = 0;
ssize_t ret = 0;
+ ssize_t off = 0;
while (i < iov_cnt) {
ssize_t r = do_write
- ? write(fd, iov[i].iov_base, iov[i].iov_len)
- : read(fd, iov[i].iov_base, iov[i].iov_len);
+ ? write(fd, iov[i].iov_base + off, iov[i].iov_len - off)
+ : read(fd, iov[i].iov_base + off, iov[i].iov_len - off);
if (r > 0) {
ret += r;
+ off += r;
+ if (off < iov[i].iov_len) {
+ continue;
+ }
} else if (!r) {
break;
} else if (errno == EINTR) {
}
break;
}
+ off = 0;
i++;
}
return ret;