2010-01-17 74 views
9

我想将二进制文件传输到远程服务器。我正在使用SUN/ONC RPC(Linux上的rpcgen)代码。我正在使用C.我已经编写了代码服务器和客户端,它适用于文本文件,但是当我尝试传输二进制文件时,它说传输后文件已损坏。我将数据块存储在字符数组或XDR字符串中。我认为将数据存储为字符数组存在一些问题。有人可以告诉我问题是什么吗?有人可以帮帮我吗?Sun RPC:传输二进制文件

我附上我的代码片段供参考,如果有人想看看我在做什么。

我的IDL:

const MAXLEN = 1024; 

/* 
* Type for storing path 
*/ 
typedef string filename<MAXLEN>; 

/* 
* Structure for sending request. Expects the path of the file 
* and the byte number at which to start reading the file from 
*/ 
struct request { 
    filename name; 
    int start; 
}; 

/* 
* Type that represents the structute for request 
*/ 
typedef struct request request; 

/* 
* Type for storing a chunk of the file that is being 
* sent from the server to the client in the current 
* remote procedure call 
*/ 
typedef string filechunk<MAXLEN>; 

/* 
* Response sent by the server to the client as a response 
* to remote procedure call, containing the filechunk for 
* the current call and number of bytes actually read 
*/ 
struct chunkreceive { 
    filechunk data; 
    int bytes; 
}; 

/* 
* Type that represents the structure for file's chunks 
* to be received from the server 
*/ 
typedef struct chunkreceive chunkreceive; 

/* 
* File data sent by the server from client to store 
* it on the server along with the filename and the 
* number of bytes in the data 
*/ 
struct chunksend { 
    filename name; 
    filechunk data; 
    int bytes; 
}; 

/* 
* Type that represents the structure for file's chunks 
* to be sent to the server 
*/ 
typedef struct chunksend chunksend; 

/* 
* union for returning from remote procedure call, returns 
* the proper chunkdata response if everything worked fine 
* or will return the error number if an error occured 
*/ 
union readfile_res switch (int errno) { 
    case 0: 
     chunkreceive chunk; 
    default: 
     void; 
}; 

/* 
* Remote procedure defined in the Interface Definition Language 
* of SUN RPC, contains PROGRAM and VERSION name definitions and 
* the remote procedure signature 
*/ 
program FTPPROG { 
    version FTPVER { 
     readfile_res retrieve_file(request *) = 1; 
     int send_file(chunksend *) = 2; 
    } = 1; 
} = 0x20000011; 

我的服务器:

#include <rpc/rpc.h> 
#include <stdio.h> 
#include "ftp.h" 

extern __thread int errno; 

readfile_res* retrieve_file_1_svc(request *req, struct svc_req *rqstp) 
{ 
    FILE *file; 
    char data[1024]; 
    int bytes; 
    static readfile_res res; 

    file = fopen(req->name, "rb"); 
    if (file == NULL) { 
     res.errno = errno; 
     return (&res); 
    } 

    fseek (file, req->start, SEEK_SET); 
    bytes = fread(data, 1, 1024, file); 

    res.readfile_res_u.chunk.data = data; 
    res.readfile_res_u.chunk.bytes = bytes; 

    /* 
    * Return the result 
    */ 
    res.errno = 0; 
    fclose(file); 
    return (&res); 
} 

int* send_file_1_svc(chunksend *rec, struct svc_req *rqstp) 
{ 
    FILE *file; 
    int write_bytes; 
    static int result; 

    file = fopen(rec->name, "a"); 
    if (file == NULL) { 
     result = errno; 
     return &result; 
    } 

    write_bytes = fwrite(rec->data, 1, rec->bytes, file); 
    fclose(file); 

    result = 0; 
    return &result; 
} 

我的客户:

#include <rpc/rpc.h> 
#include <stdio.h> 
#include <string.h> 
#include "ftp.h" 

extern __thread int errno; 

int get_file(char *host, char *name) 
{ 
    CLIENT *clnt; 
    int total_bytes = 0, write_bytes; 
    readfile_res *result; 
    request req; 
    FILE *file; 

    req.name = name; 
    req.start = 0; 

    /* 
    * Create client handle used for calling FTPPROG on 
    * the server designated on the command line. Use 
    * the tcp protocol when contacting the server. 
    */ 
    clnt = clnt_create(host, FTPPROG, FTPVER, "tcp"); 
    if (clnt == NULL) { 
     /* 
     * Couldn't establish connection with server. 
     * Print error message and stop. 
     */ 
     clnt_pcreateerror(host); 
     exit(1); 
    } 

    file = fopen(name, "wb"); 

    /* 
    * Call the remote procedure readdir on the server 
    */ 
    while (1) { 
     req.start = total_bytes; 
     result = retrieve_file_1(&req, clnt); 
     if (result == NULL) { 
      /* 
      * An RPC error occurred while calling the server. 
      * Print error message and stop. 
      */ 
      clnt_perror(clnt, host); 
      exit(1); 
     } 

     /* 
     * Okay, we successfully called the remote procedure. 
     */ 
     if (result->errno != 0) { 
      /* 
      * A remote system error occurred. 
      * Print error message and stop. 
      */ 
      errno = result->errno; 
      perror(name); 
      exit(1); 
     } 

     /* 
     * Successfully got a chunk of the file. 
     * Write into our local file. 
     */ 
     write_bytes = fwrite(result->readfile_res_u.chunk.data, 1, result->readfile_res_u.chunk.bytes, file); 
     total_bytes += result->readfile_res_u.chunk.bytes; 
     if (result->readfile_res_u.chunk.bytes < MAXLEN) 
      break; 
    } 

    fclose(file); 

    return 0; 
} 

int put_file(char *host, char *name) 
{ 
    CLIENT *clnt; 
    char data[1024]; 
    int total_bytes = 0, read_bytes; 
    int *result; 
    chunksend chunk; 
    FILE *file; 

    /* 
    * Create client handle used for calling FTPPROG on 
    * the server designated on the command line. Use 
    * the tcp protocol when contacting the server. 
    */ 
    clnt = clnt_create(host, FTPPROG, FTPVER, "tcp"); 
    if (clnt == NULL) { 
     /* 
     * Couldn't establish connection with server. 
     * Print error message and stop. 
     */ 
     clnt_pcreateerror(host); 
     exit(1); 
    } 

    file = fopen(name, "r"); 

    chunk.name = name; 

    /* 
    * Call the remote procedure readdir on the server 
    */ 
    while (1) { 
     read_bytes = fread(data, 1, MAXLEN, file); 
     total_bytes += read_bytes; 

     chunk.data = data; 
     chunk.bytes = read_bytes; 
     result = send_file_1(&chunk, clnt); 

     if (result == NULL) { 
      /* 
      * An RPC error occurred while calling the server. 
      * Print error message and stop. 
      */ 
      clnt_perror(clnt, host); 
      exit(1); 
     } 

     /* 
     * Okay, we successfully called the remote procedure. 
     */ 
     if (*result != 0) { 
      /* 
      * A remote system error occurred. 
      * Print error message and stop. 
      */ 
      errno = *result; 
      perror(name); 
      exit(1); 
     } 

     /* 
     * Successfully got a chunk of the file. 
     * Write into our local file. 
     */ 
     if (read_bytes < MAXLEN) 
      break; 
    } 

    fclose(file); 

    return 0; 
} 

int read_command(char *host) 
{ 
    char command[MAXLEN], filepath[MAXLEN]; 

    printf("> "); 
    fflush(stdin); 
    scanf("%s %s", command, filepath); 

    if (strcmp(command, "get") == 0) { 
     return get_file(host, filepath); 
    } else if(strcmp(command, "put") == 0){ 
     return put_file(host, filepath); 
    } else if(strcmp(command, "exit") == 0){ 
     exit(0); 
    } else { 
     return -1; 
    } 
} 

int main(int argc, char *argv[]) 
{ 
    int result; 

    if (argc != 2) { 
     fprintf(stderr, "usage: %s host\n", argv[0]); 
     exit(1); 
    } 

    while(TRUE) { 
     result = read_command(argv[1]); 
    } 

    return 0; 
} 

回答

4

XDR字符串以null结尾。您需要使用不同的数据类型来传输二进制数据 - 可能是“字节数组”。例如,参见Sun的document

+0

谢谢。在看到这篇文章之前,我已经完成了这项工作。无论如何这就是要走的路,我现在使用整数数组! – 2010-01-18 17:37:41

0

比较文件之前和转移后,会告诉你哪里出了问题。 您可以使用hexdiff

+0

似乎只有一小块文件即将在循环的每次迭代期间到来。在服务器端,当它读取文件时,尺寸是完美的,但是当它在客户端被接收时,它们都会搞砸。只有大约一半的数据是正确的! – 2010-01-17 19:08:44

3

有点晚了,我GESS但这里是你的问题的解决方案: 中庸之道更改类型用于存储文件的大块的 任意字节固定长度的数组。 所以在你的IDL,而不是声明“类型定义字符串filechunk <MAXLEN>;”您可以使用不透明的数据:“的typedef不透明filechunk [MAXLEN];”(实际上的问题,它是焦炭的只是一个固定阵列)

PS:这种数据(固定数组)阻止您使用变量作为缓冲区来读取或写入文件。举例来说,在功能* retrieve_file_1_svc *从你的服务器,报表

*bytes = fread(data, 1, 1024, file); 
res.readfile_res_u.chunk.data = data;* 

必须改变以

*bytes = fread(res.readfile_res_u.chunk.data, 1, 1024, file);* 
1

只是以供将来参考,Madhusudan.CS自己的“解决方案”使用整数会给您在使用不同字母顺序的机器时可享受各种乐趣。在这种情况下,RPC应该转换整数,把你的字符串或二进制数据弄糟。

正确的解决方案是使用'不透明'XDR数据类型。它将创建一个带有_len无符号整数的字节数的结构,以及一个可以指向数据的_var指针。