Recover: all 50 JPGs have "0" as first byte instead of 0xff

Question

I've been stuck for days with this problem. My recover program creates 50 jpgs but none of them show.

When I look at the first 4 bytes of each, bytes 2 - 4 are correct for JPG signature.

But byte 1 is always 0 instead of 0xff. I don't understand how this could be happening. What am I missing??? Thank you for suggestions!

int main(void)
 {
//open raw data file 
FILE* rawfile = fopen("card.raw", "r");

 // buffer to hold 512 bytes from fread 
    typedef uint8_t  BYTE;
    BYTE buffer[512]; 
    char title[7];
    FILE* img = NULL;
    int search = 0; 
    int picnumber = 0; 

  while (feof (rawfile) == 0)
  {
      fread(&buffer, 512, 1, rawfile);

   //check for next jpeg signature 


       if (buffer[0] == 0xff && buffer [1] == 0xd8 && buffer [2] == 0xff && (buffer [3] >> 4) == 0xe)
          {


          //close current
            if ( search > 0)
            {
             fclose(img);
            } 
            //open new JPG and how to display file name 
              sprintf(title, "%03d.jpg", picnumber); 
              img = fopen(title, "a" );

             //write from buffer to new jpg, 
            fwrite(&buffer, 512, 1, img);
            picnumber++;
            search = 1;
          }
      else if (search > 0)
         {  
        fwrite(&buffer, 512, 1, img);   
         }
  }

}

Answer 1

The problem is happening because the first byte of your buffer is being overwritten. The data that is being inserted is the end of string marker '\0'. It's being written there because buffer is located just after another string variable in memory. That other string variable is title[].

Why is this happening? You allocated a length of 7 chars to title. Each file name that you are creating is 7 characters long, like 000.jpg. So, when the code writes the filename out to title, where is it going to put the end of string marker '\0'? Normally, it would go into the 8th position, but title only has 7.

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