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Example of macOS sendmsg_x
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// ./usr/include/sys/syscall.h:521:#define SYS_sendmsg_x 481 | |
// ./kern/syscalls.master:751:480 AUE_NULL ALL { user_ssize_t recvmsg_x(int s, struct msghdr_x *msgp, u_int cnt, int flags); } | |
#include <sys/syscall.h> | |
#include <stdio.h> | |
#include <stdlib.h> | |
#include <stdint.h> | |
#include <string.h> | |
#include <unistd.h> | |
#include <sys/socket.h> | |
#include <netinet/in.h> | |
// from bsd/sys/socket.h | |
struct msghdr_x { | |
void *msg_name; /* optional address */ | |
socklen_t msg_namelen; /* size of address */ | |
struct iovec *msg_iov; /* scatter/gather array */ | |
int msg_iovlen; /* # elements 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 */ | |
size_t msg_datalen; /* byte length of buffer in msg_iov */ | |
}; | |
int main(int argc, char **argv) { | |
int sockfd = socket(AF_INET, SOCK_DGRAM, 0); | |
struct sockaddr_in saddr = { }; | |
saddr.sin_family = AF_INET; | |
saddr.sin_port = htons(4433); | |
memset(&saddr.sin_addr, 0x08080808, 4); // 8.8.8.8 | |
int ret = connect(sockfd, (struct sockaddr *)&saddr, sizeof(saddr)); | |
if (ret < 0) { | |
printf("Failed to connect.\n"); | |
return 1; | |
} | |
char *buf0 = "AAAAAAAAA"; | |
char *buf1 = "BBBBBBBBB"; | |
struct iovec msg_vec0 = { }; | |
struct iovec msg_vec1 = { }; | |
msg_vec0.iov_base = buf0; | |
msg_vec0.iov_len = strlen(buf0); | |
msg_vec1.iov_base = buf1; | |
msg_vec1.iov_len = strlen(buf1); | |
struct msghdr_x xmsghdr[2] = { }; | |
xmsghdr[0].msg_iov = &msg_vec0; | |
xmsghdr[0].msg_iovlen = 1; | |
xmsghdr[1].msg_iov = &msg_vec1; | |
xmsghdr[1].msg_iovlen = 1;; | |
// ./kern/syscalls.master:751:480 AUE_NULL ALL { user_ssize_t recvmsg_x(int s, struct msghdr_x *msgp, u_int cnt, int flags); } | |
ret = syscall(SYS_sendmsg_x, sockfd, &xmsghdr, 2, 0); | |
printf("ret: %d\n", ret); | |
return 0; | |
} |
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