一个网络服务程序报errno 22的情况

最新推荐文章于 2025-04-14 12:06:20 发布

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最近在学习写socket程序，然后就写了一个模拟web服务器的应答程序，下面我上源码。

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

#define BUFFER_SIZE 1024
static const char *status_line[2] = {"200 OK", "500 Internal server error"};

int main(int argc, char *argv[]){
        if(argc <= 3){
                printf("usage: %s ip_address port_number filename\n", basename(argv[0]));
                        return 1;
        }

        const char* ip = argv[1];
        int port = atoi(argv[2]);
        const char *file_name = argv[3];

        struct sockaddr_in address;
        bzero(&address, sizeof(address));
        address.sin_family = AF_INET;
        inet_pton(AF_INET, ip, &address.sin_addr);
        address.sin_port = htons(port);

        int sock = socket(PF_INET, SOCK_STREAM, 0);
        assert(sock >= 0);

        int ret = bind(sock, (struct sockaddr*)&address, sizeof(address));
        assert(ret != -1);

        struct sockaddr_in client;
        socklen_t client_addrlength = sizeof(client);
        int connfd = accept(sock, (struct sockaddr*)&client, &client_addrlength);
        if(connfd < 0){
                printf("errno is : %d\n", errno);
        }else{
                char header_buf[BUFFER_SIZE];
                memset(header_buf, '\0', BUFFER_SIZE);
                char *file_buf;
                struct stat file_stat;
                bool valid = true;
                int len = 0;
                if(stat(file_name, &file_stat) < 0){
                        valid = false;
                }else{
                        if(S_ISDIR(file_stat.st_mode)){
                                valid = false;
                        }else if(file_stat.st_mode & S_IROTH){
                                int fd = open(file_name, O_RDONLY);
                                file_buf = new char[file_stat.st_size + 1];
                                memset(file_buf, '\0', file_stat.st_size + 1);
                                if(read(fd, file_buf, file_stat.st_size) < 0){
                                        valid = false;
                                }
                        }else{
                                valid = false;
                        }
                }

                if(valid){
                        ret = snprintf(header_buf, BUFFER_SIZE-1, "%s %s\r\n", "HTTP/1.1",
                                status_line[0]);

                        len += ret;
                        ret = snprintf(header_buf + len, BUFFER_SIZE-1-len,
                                "Content-Length: %d\r\n", file_stat.st_size);
                        len += ret;

                        ret = snprintf(header_buf + len, BUFFER_SIZE-1-len, "%s", "\r\n");

                        struct iovec iv[2];
                        iv[0].iov_base = header_buf;
                        iv[0].iov_len = strlen(header_buf);
                        iv[1].iov_base = file_buf;
                        iv[1].iov_len = file_stat.st_size;
                        ret = writev(connfd, iv, 2);
                }else{
                        ret = snprintf(header_buf, BUFFER_SIZE-1, "%s %s\r\n",
                                "HTTP/1.1", status_line[1]);
                        len += ret;
                        ret = snprintf(header_buf + len, BUFFER_SIZE-1-len, "%s", "\r\n");
                        send(connfd, header_buf, strlen(header_buf), 0);
                }

                close(connfd);
                delete[] file_buf;
        }

        close(sock);
        return 0;
}

我编译运行之后，总是报errno 22的错误。

./writev 192.168.91.128 5555 count1.c

errno is : 22

因为这个实在accept的函数中打印出来了，我查了一下errno，说是参数错误，然后我就去翻accept的定义啊，看了很久，觉得没什么问题啊。

然后上优快云，也看到一个小伙伴报同样的错误，我就看了下他贴上来的源码，突然看到了listen，恍然大悟啊，我竟然在bind之后没有listen~~~~~~

可恶啊！！！

后来加上listen之后就没有问题了。

完整的源码：

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

#define BUFFER_SIZE 1024
static const char *status_line[2] = {"200 OK", "500 Internal server error"};

int main(int argc, char *argv[]){
        if(argc <= 3){
                printf("usage: %s ip_address port_number filename\n", basename(argv[0]));
                        return 1;
        }

        const char* ip = argv[1];
        int port = atoi(argv[2]);
        const char *file_name = argv[3];

        struct sockaddr_in address;
        bzero(&address, sizeof(address));
        address.sin_family = AF_INET;
        inet_pton(AF_INET, ip, &address.sin_addr);
        address.sin_port = htons(port);

        int sock = socket(PF_INET, SOCK_STREAM, 0);
        assert(sock >= 0);

        int ret = bind(sock, (struct sockaddr*)&address, sizeof(address));
        assert(ret != -1);

        ret = listen(sock, 5);
        assert(ret != -1);

        struct sockaddr_in client;
        socklen_t client_addrlength = sizeof(client);
        int connfd = accept(sock, (struct sockaddr*)&client, &client_addrlength);
        if(connfd < 0){
                printf("errno is : %d\n", errno);
        }else{
                char header_buf[BUFFER_SIZE];
                memset(header_buf, '\0', BUFFER_SIZE);
                char *file_buf;
                struct stat file_stat;
                bool valid = true;
                int len = 0;
                if(stat(file_name, &file_stat) < 0){
                        valid = false;
                }else{
                        if(S_ISDIR(file_stat.st_mode)){
                                valid = false;
                        }else if(file_stat.st_mode & S_IROTH){
                                int fd = open(file_name, O_RDONLY);
                                file_buf = new char[file_stat.st_size + 1];
                                memset(file_buf, '\0', file_stat.st_size + 1);
                                if(read(fd, file_buf, file_stat.st_size) < 0){
                                        valid = false;
                                }
                        }else{
                                valid = false;
                        }
                }

                if(valid){
                        ret = snprintf(header_buf, BUFFER_SIZE-1, "%s %s\r\n", "HTTP/1.1",
                                status_line[0]);

                        len += ret;
                        ret = snprintf(header_buf + len, BUFFER_SIZE-1-len,
                                "Content-Length: %d\r\n", file_stat.st_size);
                        len += ret;

                        ret = snprintf(header_buf + len, BUFFER_SIZE-1-len, "%s", "\r\n");

                        struct iovec iv[2];
                        iv[0].iov_base = header_buf;
                        iv[0].iov_len = strlen(header_buf);
                        iv[1].iov_base = file_buf;
                        iv[1].iov_len = file_stat.st_size;
                        ret = writev(connfd, iv, 2);
                }else{
                        ret = snprintf(header_buf, BUFFER_SIZE-1, "%s %s\r\n",
                                "HTTP/1.1", status_line[1]);
                        len += ret;
                        ret = snprintf(header_buf + len, BUFFER_SIZE-1-len, "%s", "\r\n");
                        send(connfd, header_buf, strlen(header_buf), 0);
                }

                close(connfd);
                delete[] file_buf;
        }

        close(sock);
        return 0;
}

输出结果：

[root@localhost C]# telnet 192.168.91.128 5555
Trying 192.168.91.128...
Connected to 192.168.91.128.
Escape character is '^]'.
HTTP/1.1 200 OK
Content-Length: 270

#include <stdio.h>

int main(){
        int input;
        int flag = 1;
        int count = 0;
        scanf("%d",&input);
        printf("input is %d\n", input);
        while(flag){
                if(input & flag){
                        count++;
                }

                flag <<= 1;
        }

        printf("the number has %d 1 in binary mode.\n", count);
        return 0;
}
Connection closed by foreign host.

完！