标签：style c int a 文件 string
socketpair:
功能：创建一个全双工的流管道
原型
int socketpair(int domain, int type, int protocol, int sv[2]);
参数
domain: 协议家族
type: 套接字类型
protocol: 协议类型
sv: 返回套接字对
返回值：成功返回0；失败返回-1
ssize_t sendmsg(int sockfd, const struct msghdr *msg, int flags);
ssize_t recvmsg(int sockfd, struct msghdr *msg, int flags);
sendfd.c
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#define ERR_EXIT(m) \
do \
{ \
perror(m); \
exit(EXIT_FAILURE); \
} while(0)
void send_fd(int sock_fd, int send_fd)
{
int ret;
struct msghdr msg;
struct cmsghdr *p_cmsg;
struct iovec vec;
char cmsgbuf[CMSG_SPACE(sizeof(send_fd))];
int *p_fds;
char sendchar = 0;
msg.msg_control = cmsgbuf;
msg.msg_controllen = sizeof(cmsgbuf);
p_cmsg = CMSG_FIRSTHDR(&msg);
p_cmsg->cmsg_level = SOL_SOCKET;
p_cmsg->cmsg_type = SCM_RIGHTS;
p_cmsg->cmsg_len = CMSG_LEN(sizeof(send_fd));
p_fds = (int*)CMSG_DATA(p_cmsg);
*p_fds = send_fd;
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_iov = &vec;
msg.msg_iovlen = 1;
msg.msg_flags = 0;
vec.iov_base = &sendchar;
vec.iov_len = sizeof(sendchar);
ret = sendmsg(sock_fd, &msg, 0);
if (ret != 1)
ERR_EXIT("sendmsg");
}
int recv_fd(const int sock_fd)
{
int ret;
struct msghdr msg;
char recvchar;
struct iovec vec;
int recv_fd;
char cmsgbuf[CMSG_SPACE(sizeof(recv_fd))];
struct cmsghdr *p_cmsg;
int *p_fd;
vec.iov_base = &recvchar;
vec.iov_len = sizeof(recvchar);
msg.msg_name = NULL;
msg.msg_namelen = 0;
msg.msg_iov = &vec;
msg.msg_iovlen = 1;
msg.msg_control = cmsgbuf;
msg.msg_controllen = sizeof(cmsgbuf);
msg.msg_flags = 0;
p_fd = (int*)CMSG_DATA(CMSG_FIRSTHDR(&msg));
*p_fd = -1;
ret = recvmsg(sock_fd, &msg, 0);
if (ret != 1)
ERR_EXIT("recvmsg");
p_cmsg = CMSG_FIRSTHDR(&msg);
if (p_cmsg == NULL)
ERR_EXIT("no passed fd");
p_fd = (int*)CMSG_DATA(p_cmsg);
recv_fd = *p_fd;
if (recv_fd == -1)
ERR_EXIT("no passed fd");
return recv_fd;
}
int main(void)
{
int sockfds[2];
if (socketpair(PF_UNIX, SOCK_STREAM, 0, sockfds) < 0)
ERR_EXIT("socketpair");
pid_t pid;
pid = fork();
if (pid == -1)
ERR_EXIT("fork");
if (pid > 0)
{
close(sockfds[1]);
int fd = recv_fd(sockfds[0]);
char buf[1024] = {0};
read(fd, buf, sizeof(buf));
printf("buf=%s\n", buf);
}
else if (pid == 0)
{
close(sockfds[0]);
int fd;
fd = open("test.txt", O_RDONLY);
if (fd == -1);
send_fd(sockfds[1], fd);
}
return 0;
}
socketpair.c
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#define ERR_EXIT(m) \
do \
{ \
perror(m); \
exit(EXIT_FAILURE); \
} while(0)
int main(void)
{
int sockfds[2];
if (socketpair(PF_UNIX, SOCK_STREAM, 0, sockfds) < 0)
ERR_EXIT("socketpair");
pid_t pid;
pid = fork();
if (pid == -1)
ERR_EXIT("fork");
if (pid > 0)
{
int val = 0;
close(sockfds[1]);
while (1)
{
++val;
printf("sending data: %d\n", val);
write(sockfds[0], &val, sizeof(val));
read(sockfds[0], &val, sizeof(val));
printf("data received: %d\n", val);
sleep(1);
}
}
else if (pid == 0)
{
int val;
close(sockfds[0]);
while (1)
{
read(sockfds[1], &val, sizeof(val));
++val;
write(sockfds[1], &val, sizeof(val));
}
}
return 0;
}
makefile:
.PHONY:clean all
CC=gcc
CFLAGS=-Wall -g
BIN=socketpair send_fd
all:$(BIN)
%.o:%.c
$(CC) $(CFLAGS) -c $< -o $@
clean:
rm -f *.o $(BIN)
UNIX进程之间传递文件描述符recvmsg与sendmsg,布布扣,bubuko.com
UNIX进程之间传递文件描述符recvmsg与sendmsg
标签：style c int a 文件 string
原文地址：http://blog.csdn.net/fuyuehua22/article/details/25919503
