Hi,
Here is a first shot. Maybe in the dark..
> Thanks for this investigation. So far it sounds like everything is
> right, but I will follow your further analysis with interest.
One problem could be socklen_t. Linux uses size_t [1].
(yes I read the comment in the code "To forestall portability problems")
(I do not know Mac:s structs, also 32 bit probably size_t and socklen_t
are 4 )
I have not enough Python/C interface knowledge to know what dragons
are hidden there..
For example the cast :
message_header.msg_controllen = (socklen_t) all_data_len;
puts an int in the msg.controllen but an long long is expected?
That cast might not be as bad as setting some length using &.
Under linux[2] here, the sizeof is :
sizeof socklen_t 4
sizeof size_t 8
There are several casts (socklen_t) and removing them did not
yet solve the problem. There must be some other error as well.
The transformer t# means char* + int. I added a tmp varible for iovec
as it is also size_t[3].
There are several points and I have tried to fix things, but was
not yet successful.
I need to read up on and create a working under linux sendmsg I think to
have something to compare to.
Rebuilding the full calendar server for each test does not make sense.
> Please feel free to bother me until I respond when you do :).
Hehe, leaving for vacation today, so I might not be able to follow up
for a while.
> Given that the problem thus far has been in some C wrapping for the
> standard APIs, I'd rather figure out what the existing problem is than
> introduce a new dependency and then write a bunch of _new_ C code
> wrapping those APIs.
Sure, I understand. The above library also does not seem to be actively
developed.
[1]
http://www.kernel.org/doc/man-pages/online/pages/man2/send.2.html
struct msghdr {
void *msg_name; /* optional address */
socklen_t msg_namelen; /* size of address */
struct iovec *msg_iov; /* scatter/gather array */
size_t msg_iovlen; /* # elements in msg_iov */
void *msg_control; /* ancillary data, see below */
size_t msg_controllen; /* ancillary data buffer len */
int msg_flags; /* flags on received message */
};
http://pubs.opengroup.org/onlinepubs/007908775/xns/syssocket.h.html
void *msg_name optional address
socklen_t msg_namelen size of address
struct iovec *msg_iov scatter/gather array
int msg_iovlen members in msg_iov
void *msg_control ancillary data, see below
socklen_t msg_controllen ancillary data buffer len
int msg_flags flags on received message
[2]
#include <sys/socket.h>
#include <stdio.h>
main() {
socklen_t t;
size_t s;
printf("sizeof socklen_t %d\n", sizeof(t));
printf("sizeof size_t %d\n", sizeof(s));
}
[3]
struct iovec
{
void *iov_base; /* Pointer to data. */
size_t iov_len; /* Length of data. */
};