cgiparsem.c

闻停开发板视频程序

//--------------------------------------------------------------------------
// IP Stack CGI Demonstration Program
//--------------------------------------------------------------------------
// cgiparsem.c
//
// Multipart CGI Parsing for "multipart/form-data" forms
//
// Author: Michael A. Denio
//
// Copyright 2003 by Texas Instruments Inc.
//-------------------------------------------------------------------------
#include <netmain.h>
#include <_stack.h>
#include "cgiparsem.h"

//
// myscan()
//
// Simple scan function. Returns the index of the start of
// the terminator from the beginning of the buffer.
//
static int myscan( char *buffer, char *terminator, int buflen )
{
    int i,len;

    len = strlen( terminator );

    buflen -= len;

    for( i=0; buflen>=0; i++, buflen-- )
    {
        if( !strncmp( buffer+i, terminator, len ) )
            return(i);
    }

    return(-1);
}

static char *CGI_CRLF = "\r\n";

//
// cgiParseMultiVars()
//
// This function is used to parse CGI data sent in the "multipart/form-data"
// format. The caller must pass in the entire CGI payload as a single buffer.
// The buffer will altered to add NULL termination to all names, types, and
// data fields.
//
// Returns the number of validated records, or -1 on parsing error.
//
int cgiParseMultiVars( char *buffer, int buflen, CGIPARSEREC *recs, int maxrecs )
{
    char *divider;
    int  i,numrecs,fname;
    char *tstr,*tmark,*tmarkv;
    int  tlen,divlen;
    char c;


    // Clear out the entire recs[] array
    mmZeroInit( recs, sizeof(CGIPARSEREC) * maxrecs );

    // First, read in our divider. The buffer must start with "--".
    if( *buffer!='-' || *(buffer+1)!='-' )
        return(-1);

    // Scan for "\r\n" and put in "divider"
    i = myscan( buffer, CGI_CRLF, buflen );
    if( i < 3 )         // Minimum divider is "--?"
        return(-1);
    divider = buffer;
    divlen  = i;
    *(divider+i) = 0;   // Null terminate the string
    buffer += i+2;     // Step past the "/r/n"
    buflen -= i+2;

    numrecs = 0;
    fname = 0;
    for( ;; )
    {
        // Scan in the next token
        i = myscan( buffer, CGI_CRLF, buflen );
        if( i < 0 )
            return(-1);

        // If i==0, then we hit a "/r/n/r/n", in which case the
        // next field should be the data.
        if( !i )
        {
            buffer += 2;     // Step past the "/r/n"
            buflen -= 2;

            // We must have read a name by now or we have an error
            if( !fname )
                return(-1);

            // Scan for the divider
            i = myscan( buffer, divider, buflen );
            if( i < 2 )         // Minimum is "/r/nDivider"
                return(-1);

            // Two chars before divider must be "/r/n"
            if( *(buffer+i-2)!='\r' || *(buffer+i-1)!='\n' )
                return(-1);

            // Null terminate and record info
            *(buffer+i-2) = 0;
            (recs+numrecs)->Data = buffer;
            (recs+numrecs)->DataSize = i-2;

            // We're done with this record
            if( ++numrecs == maxrecs )
                return( numrecs );

            // Step past the data and the divider
            buffer += i+divlen;
            buflen -= i+divlen;

            // This scan must be either "2" or Zero
            i = myscan( buffer, CGI_CRLF, buflen );

            if( i==2 )
            {
                // This may be the real terminator. At the end of
                // the buffer, the data should be "--/r/n", so...
                if( *buffer=='-' && *(buffer+1)=='-' )
                    return( numrecs );
                else
                    return( -1 );

            }

            if( i!=0 )
                return( -1 );

            // Setup for next record
            fname = 0;
            buffer += 2;
            buflen  -= 2;

            continue;
        }

        //
        // Here we have a tag that precedes the data. The tag starts
        // at [buffer], and is [i] characters in length.

        //
        // See if the tag is "Content-Disposition:"
        //
        if( !strncmp( buffer, "Content-Disposition:", 20 ) )
        {
            // We now do a sub-parsing on this string
            tstr = buffer+20;
            tlen = i-20;

            // Step the main status beyond this tag
            buffer += i+2;     // Step past the "/r/n"
            buflen -= i+2;

            // Sub-parse the tag
            tmark = tstr;
            while( tlen > 0 )
            {
                c = *tstr++;
                tlen--;

                if( c==' ' || c==';' )
                    tmark = tstr;

                if( c=='=' )
                {
                    // Null terminate the field name
                    *(tstr-1) = 0;

                    // Find the quotes
                    tmarkv = 0;
                    i = 0;
                    while( tlen > 0 )
                    {
                        c = *tstr++;
                        tlen--;

                        if( c=='"' )
                        {
                            if( ++i == 1 )
                                tmarkv = tstr;
                            else
                                break;
                        }
                    }

                    // If we didn't get two quotes, we have an error
                    if( i != 2 )
                        return(-1);

                    // Null terminate the field value
                    *(tstr-1) = 0;

                    // We look for "name" and "filename" strings
                    if( !strcmp( tmark, "name" ) )
                    {
                        (recs+numrecs)->Name = tmarkv;
                        fname = 1;
                    }

                    if( !strcmp( tmark, "filename" ) )
                        (recs+numrecs)->Filename = tmarkv;
                }
            }

            continue;
        }


        //
        // See if the tag is "Content-Type:"
        //
        if( !strncmp( buffer, "Content-Type:", 13 ) )
        {
            // We now do a sub-parsing on this string
            tstr = buffer+13;
            tlen = i-13;

            // Step the main status beyond this tag
            buffer += i+2;     // Step past the "/r/n"
            buflen -= i+2;

            // Here we'll just remove any leading spaces
            while( *tstr == ' ' )
            {
                tstr++;
                tlen--;
            }

            // Null terminate the string
            *(buffer-2) = 0;

            // Record it
            (recs+numrecs)->Type = tstr;

            continue;
        }

        // This is a tag we don't care about - just step past it
        buffer += i+2;     // Step past the "/r/n"
        buflen -= i+2;
    }
}