Question

我在linux编码方面遇到了问题。

当我向服务器发送文件名时，我得到服务器中的segmentation fault。

可能会在阅读中发生。

但是，我无法找到解决问题的想法。

有什么建议吗？

客户端源代码

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

#define BUFMAX 256

void error_handling(const char *msg)
{
        fputs(msg, stderr);
        fputc('\n', stderr);
        exit(0);
}

int main(int argc, char *argv[])
{
        int sockfd, h_err;
        int file_len = 0;
        int buf_size = 0;
        struct sockaddr_in serv_addr;
        struct hostent *server;
        char buffer[BUFMAX];
        FILE *file;
        char *file_name;
        char *file_cont;

        if (argc < 2)
                error_handling("ERROR! No simulator provided\n");

        sockfd = socket(AF_INET, SOCK_STREAM, 0);
        if (sockfd < 0)
                error_handling("ERROR opening socket\n");

        memset(&serv_addr, 0, sizeof(serv_addr));
        serv_addr.sin_family = AF_INET;
        serv_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
        serv_addr.sin_port = htons(5000);

        if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0)
                error_handling("ERROR connecting");

        // file handling
        file_name = (char *)malloc(strlen(argv[1]));
        file_len = strlen(argv[1]);
        memcpy(file_name, argv[1], file_len);
        file = fopen(file_name, "rb");
        if(file == NULL)
                error_handling("File is not exis!\n");

        // send file name
        h_err = write(sockfd, file_name, file_len);
        if(h_err < 0)
                error_handling("ERROR writing to socket!\n");

        // file handling
        fseek(file, 0, 2);
        file_len = ftell(file);
        fseek(file, 0, 0);

        // send file size
        memset(buffer, 0, BUFMAX);
        sprintf(buffer, "%d", file_len);
        h_err = write(sockfd, buffer, strlen(buffer));
        if(h_err < 0)
                error_handling("ERROR writing to socket!\n");

        file_cont = (char *)malloc(file_len);
        while( !feof(file) )
        {
                fgets(buffer, BUFMAX, file);
                memcpy(file_cont + buf_size, buffer, strlen(buffer));
                buf_size = strlen(buffer);
        }
        h_err = send(sockfd, file_cont, file_len, 0);
        if(h_err < 0)
                error_handling("ERROR sending to socket");

        printf("File sending....\n");

        fclose(file);
        close(sockfd);

        return 0;
}

服务器源代码

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

#define BUFMAX 8000

void error_handling(const char *msg)
{
        fputs(msg, stderr);
        fputc('\n', stderr);
        exit(1);
}

int main(int argc, char *argv[])
{
        int sockfd, newsockfd, h_err;
        int file_len = 0;
        char buffer[BUFMAX];
        struct sockaddr_in serv_addr, cli_addr;
        FILE *file;
        char *file_name;
        char file_cont[BUFMAX];
        socklen_t clilen;

        sockfd = socket(AF_INET, SOCK_STREAM, 0);
        if (sockfd < 0)
           error_handling("ERROR opening socket");

        memset(&serv_addr, 0, sizeof(serv_addr));
        serv_addr.sin_family = AF_INET;
        serv_addr.sin_addr.s_addr = INADDR_ANY;
        serv_addr.sin_port = htons(5000);
        if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
                    error_handling("ERROR on binding");

        listen(sockfd, 5);
        clilen = sizeof(cli_addr);

        while(1)
        {
                newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);
                if (newsockfd < 0)
                        error_handling("ERROR on accept");

                // receive file name
                memset(buffer, 0x00, BUFMAX);
                h_err = read(newsockfd, buffer, BUFMAX);
                if (h_err < 0)
                {
                        close(sockfd);
                        close(newsockfd);
                        error_handling("ERROR reading from socket");
                }
                strcpy(file_name, buffer);
                printf("File name = %s\n", file_name);

                // receive file size
                memset(buffer, 0, BUFMAX);
                h_err = read(newsockfd, buffer, BUFMAX);
                if (h_err < 0)
                {
                        close(sockfd);
                        close(newsockfd);
                        error_handling("ERROR reading from socket");
                }
                file_len = atoi(buffer);

                // file handling
                file = fopen(file_name, "wb");
                h_err = recv(newsockfd, file_cont, file_len, 0);
                if(h_err < 0)
                {
                        close(sockfd);
                        close(newsockfd);
                        error_handling("ERROR receive from socket");
                }
                printf("Recived client file\n");
                fwrite(file_cont, 1, file_len, file);

                close(newsockfd);
        }
        fclose(file);
        close(sockfd);

        return 0;
}

Answer 1

我尝试调试你的代码。我发现您忘记在服务器代码中为var“file_name”分配内存大小。

尝试为代码分配代码中的以下行。

file_name = (char *)malloc(LEN_FILE_NAME);

问题可以解决。

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