Working with exe files in c

Question

(Working on Windows 8) I'm trying to get the size of section headers in an exe file (PE32 Format) with c. From what I read, the offset from this field is 60 so I tried reading from there.

This is the code I used:

unsigned char offset;
fseek(file, 60, SEEK_SET);
fread(&offset, sizeof(offset), 1, file);
printf("%hu", offset);

My Question is how can i get the size of the section headers? if its not on offset 60, how can i find this?

Answer 1

This should work:

void main()
{
  FILE *file = fopen("your_exe_file.exe", "rb") ;

  long peheaderoffset ;
  // read the offset of the PE header which is located at offset 0x3c
  fseek(file, 0x3c, SEEK_SET) ;
  fread(&peheaderoffset, sizeof(long), 1, file) ;

  char PEHeader[4] ;  // PE header: contains normally 'P','E',0,0
  fseek(file, peheaderoffset, SEEK_SET) ;
  fread(&PEHeader, 4, 1, file) ;

  short machine ;
  short NumberofSections ;

  fread(&machine, sizeof(short), 1, file) ;  // read machine identifier
  fread(&NumberofSections, sizeof(short), 1, file) ;  // read Number of sections

  printf ("PE Header = %s\n", PEHeader) ; // should always print "PE"
                                          // we should check if PEHEeader actually
                                          // contains "PE". If not it's not a PE file
  printf ("machine = %x\n", machine) ;    // 14c for Intel x86
  printf ("Number of sections = %d\n", NumberofSections) ; 

  // skip to size of optional header
  fseek(file, 12, SEEK_CUR) ;

  short SizeOfOptionalHeader ;
  fread (&SizeOfOptionalHeader, sizeof(short), 1, file) ;
  printf ("Sizeof optional PE header = %d\n", SizeOfOptionalHeader) ;  

  short characteristics ;
  fread (&characteristics, sizeof(short), 1, file) ;
  printf ("Characteristics = %x\n", characteristics) ;  

  // now we are at the PE optional header
  short signature ;
  fread (&signature, sizeof(short), 1, file) ;
  printf ("Signature of optioan PE Header = %d (should be 267)\n", signature) ;  

  // skip to image Base at offset 0x1c
  // (the -2 is because we have already read the signature just above)
  fseek(file, 0x1c - 2, SEEK_CUR) ;
  long imageBase ;
  fread (&imageBase, sizeof(long), 1, file) ;
  printf ("Image base = %x\n", imageBase) ;   
}