CGI download file

HTML:

<form action="http://192.168.1.1/cgi-bin/test.cgi"
enctype="multipart/form-data" method="post">
<p>
Type some text (if you like):<br>
<input type="text" name="textline" size="30">
</p>
<p>
Please specify a file, or a set of files:<br>
<input type="file" name="datafile" size="40">
</p>
<div>
<input type="submit" value="Send">
</div>
</form>

C: 再送檔前會有 0x0D 0x0A 這些要處理掉，尾巴也會有，而且還帶bondary "-------" n個不等，這些用 fget 會有問題，檔內有 0x0 也會造成問題，取檔前可用fget抓，取檔時改用read 開始取檔。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>



#define DATAFILE "/data/data.txt"
#define DEFSIZE 256

int main(void){
       char    *lenstr;
       long    len;
       int     ret;
       char    buf[ DEFSIZE ];

       printf("%s%c%c\n","Content-Type:text/html;charset=iso-8859-1",13,10);
       printf("<TITLE>Response</TITLE>\n");
       lenstr = getenv("CONTENT_LENGTH");

       if(lenstr == NULL || sscanf(lenstr,"%ld",&len)!=1 )
                 printf("<P>Error in invocation - wrong FORM probably.%d", len);
       else{

               FILE    *wfd;
               char    *retstr, *bufptr, delim[5]={ 0x0d, 0x0a, 0x2d, 0x2d, 0x0 };
               int     lastsize;


               wfd = fopen( DATAFILE, "w+");
               do{
                       if( (retstr = fgets( buf, DEFSIZE, stdin) ) == NULL ) return -1;
                       if( strstr( buf, "Content-Type" ) != NULL ) break;
               }while( 1 );
               fgets( buf, 2, stdin); // 0x0d
               fgets( buf, 2, stdin); // 0x0a
               do{
                       ret = fread( buf, 1, DEFSIZE, stdin);
                       if( ret > 0 ){
                               if( ret != DEFSIZE ){
                                       retstr = strstr( buf, delim);
                                       bufptr = buf;
                                       lastsize = retstr - bufptr;
                                       printf("write last size=%d %s\n", lastsize, retstr);
                                       fwrite( buf, 1, lastsize, wfd );
                               }
                               else{
                                       printf("writee=%d\n", ret );
                                       fwrite( buf, 1, ret, wfd );
                               }
                       }
                       else    printf("stdin error ret=%d len=%d\n", ret, len );

               }while( ret == DEFSIZE);

               fclose( wfd );
               printf("<P>Thank you! Your contribution has been stored. total len=%d", len);
       }
       return 0;
}

Reference:

• Getting Started w/ CGI Programming in C.