1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
|
#define _GNU_SOURCE
#include <sys/socket.h>
#include <limits.h>
#include <errno.h>
#include "syscall.h"
int sendmmsg(int fd, struct mmsghdr *msgvec, unsigned int vlen, unsigned int flags)
{
#if LONG_MAX > INT_MAX
/* Can't use the syscall directly because the kernel has the wrong
* idea for the types of msg_iovlen, msg_controllen, and cmsg_len,
* and the cmsg blocks cannot be modified in-place. */
int i;
if (vlen > IOV_MAX) vlen = IOV_MAX; /* This matches the kernel. */
if (!vlen) return 0;
for (i=0; i<vlen; i++) {
/* As an unfortunate inconsistency, the sendmmsg API uses
* unsigned int for the resulting msg_len, despite sendmsg
* returning ssize_t. However Linux limits the total bytes
* sent by sendmsg to INT_MAX, so the assignment is safe. */
ssize_t r = sendmsg(fd, &msgvec[i].msg_hdr, flags);
if (r < 0) goto error;
msgvec[i].msg_len = r;
}
error:
return i ? i : -1;
#else
return syscall_cp(SYS_sendmmsg, fd, msgvec, vlen, flags);
#endif
}
#ifdef TEST
int
main(void) {
return 0;
}
#endif
|
