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;
}