linux客户端服务器回射程序-编程记录

#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<unistd.h>
#include<string.h>
#include<errno.h>
#include<netinet/in.h>

#define MAXLINE 4096
#define LISTEN_NUM 1024
#define SERV_PORT 9877

size_t my_write(int sock_fd, const void *vptr, int n) {
size_t left = n;
size_t nwritten = 0;
const char *p = vptr;
while (left > 0) {
if ((nwritten = write(sock_fd, p, left)) <= 0) {
if (n < 0 && errno == EINTR)
nwritten = 0;
else
return -1;
}
left -= nwritten;
p += nwritten;
}
return n;
}

void str_echo(int sock_fd) {
size_t nread;
size_t nwritten;
char buf[MAXLINE];

again:
while ((nread = read(sock_fd, buf, MAXLINE)) > 0) {
nwritten = my_write(sock_fd, buf, nread);
printf("%s", buf);
printf("server write to client:%d\n", nwritten);
}
if (nread < 0 && errno == EINTR)
goto again;
else if (nread < 0) {
printf("error:server read from client failed.\n");
}
}

int main(int argc, char *argv[]) {
socklen_t len;
pid_t pid;
int listen_fd, client_fd;
struct sockaddr_in server_addr, client_addr;
if ((listen_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
printf("error: create listen socket failed.\n");
return -1;
}
bzero(&server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(SERV_PORT);
server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
bind(listen_fd, (struct sockaddr*)&server_addr, sizeof(server_addr));
listen(listen_fd, LISTEN_NUM);
while (1) {
len = sizeof(client_addr);
client_fd = accept(listen_fd, (struct sockaddr*)&client_addr, &len);
if ((pid = fork()) == 0) {
close(listen_fd);
str_echo(client_fd);
exit(0);
}
close(client_fd);
}
return 0;
}

客户端：

#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<errno.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<string.h>
#include<netinet/in.h>

#define MAXLINE 4096
#define SERV_PORT 9877

size_t my_write(int sock_fd, const void *vptr, size_t n) {
size_t left = n;
size_t nwritten = 0;
const char *p = vptr;
while (left > 0) {
if ((nwritten = write(sock_fd, p, left)) <= 0) {
if (nwritten < 0 && errno == EINTR)
nwritten = 0;
else
return -1;
}
left -= nwritten;
p += nwritten;
}
return n;
}

static int read_cnt;
static char *read_ptr;
static char read_buf[MAXLINE];

int my_read(int sock_fd, char *c) {
if (read_cnt <= 0) {
again:
if ((read_cnt = read(sock_fd, read_buf, sizeof(read_buf))) < 0) {
if (read_cnt < 0 && errno == EINTR)
goto again;
return -1;
} else if (read_cnt == 0) {
return 0;
}
read_ptr = read_buf;
}
read_cnt--;
*c = *read_ptr++;
return 1;
}

size_t read_line(int sock_fd, char *buf, size_t max) {
size_t n, rc;
char c;
char *p = buf;
for (n = 1; n < max; n++) {
if ((rc = my_read(sock_fd, &c)) == 1) {
*p++ = c;
if (c == '\n')
break;
} else if (rc == 0) {
*p = '\0';
return n - 1;
} else {
return -1;
}
}
*p = '\0';
return n;
}

void str_client(FILE *fp, int sock_fd) {
char sendline[MAXLINE];
char recvline[MAXLINE];
size_t n;
while (fgets(sendline, MAXLINE, fp) != NULL) {
n = strlen(sendline);
my_write(sock_fd, sendline, n);
if (read_line(sock_fd, recvline, MAXLINE) == 0) {
printf("error:client read from server failed.\n");
}
fputs(recvline, stdout);
}
}

int main(int argc, char *argv[]) {
int client_fd;
struct sockaddr_in server_addr;
if (argc != 2) {
printf("error: use <filename>IpAddress.\n");
return -1;
}
client_fd = socket(AF_INET, SOCK_STREAM, 0);
bzero(&server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(SERV_PORT);
inet_pton(AF_INET, argv[1], &server_addr.sin_addr);
connect(client_fd, (struct sockaddr*)&server_addr, sizeof(server_addr));
str_client(stdin, client_fd);
return 0;
}