Re: [Condor-users] Checking if a binary file is compiled for condor

[Erik Paulson <epaulson@xxxxxxxxxxx>]

On Tue, Oct 23, 2007 at 06:36:46PM -0400, Bruno Goncalves wrote:
> Dear All,
> 
> I would like to write a C/C++ program to verify if a given executable
> has been compiled with condor_compile or not. In the command line, I
> know that something like this:
> 
> strings foo_condor.x | grep -m 1 condor_exec.exe | wc -l
> 
> works, returning one (or zero) if the string condor_exec.exe is
> defined (or not) inside the file foo_condor.x. Is there anyway of
> detecting this inside C? For instance, how does condor check for this?
> Thanks!
> 

Condor opens up the file, scans through it looking for the string
$CondorVersion:
then reads to the next '$' character. 

It's not foolproof, if you submited the schedd as a std universe job it
would say it's valid. (I suppose the more worrisome example would be 
forgetting universe=scheduler when submitting a DAGMan, since Condor 
might still default to the std universe for jobs)

-Erik

      // Look for the magic version string
        // '$CondorVersion: x.y.z <date> <extra info> $' in the file.
        // What we look for is a string that begins with '$CondorVersion: '
        // and continues with a non-NULL character. We need to be careful
        // not to match the string '$CondorVersion: \0' which this file
        // includes as static data in a Condor executable.
    int i = 0;
    bool got_verstring = false;
    const char* verprefix = "$CondorVersion: ";
    int ch;
    while( (ch=fgetc(fp)) != EOF ) {
        if ( verprefix[i] == '\0' && ch != '\0' ) {
            do {
                ver[i++] = ch;
                if ( ch == '$' ) {
                    got_verstring = true;
                    ver[i] = '\0';
                    break;
                }
            } while ( (i < maxlen) && ((ch=fgetc(fp)) != EOF) );
            break;
        }

        if ( ch != verprefix[i] ) {
            i = 0;
            if ( ch != verprefix[0] ) {
                continue;
            }
        }

        ver[i++] = ch;
	}