[PATCH] dtrace: Use deterministic temp file creation for all temp files

[Florian Weimer]

* Gioele Barabucci via Systemtap:

> +def mktemp_determ(sources, suffix):
> +    # for reproducible-builds purposes, use a predictable tmpfile path
> +    sha = hashlib.sha256()
> +    for source in sources:
> +        sha.update(source.encode('utf-8'))
> +    fname = ".dtrace-temp." + sha.hexdigest()[:8] + suffix
> +    tries = 0
> +    while True:
> +        tries += 1
> +        if tries > 100: # if file exists due to previous crash or whatever
> +            raise Exception("cannot create temporary file \""+fname+"\"")
> +        try:
> +            wxmode = 'x' if sys.version_info > (3,0) else 'wx'
> +            fdesc = open(fname, mode=wxmode)
> +            break
> +        except FileExistsError:
> +            time.sleep(0.1) # vague estimate of elapsed time for concurrent identical gcc job
> +            pass # Try again
> +
> +    return fdesc, fname

This looks like creating a file with a suitable name may block forward
progress indefinitely?  Like from a previous crash of the tool?

It might be more robust to use a dedicated temporary directory and a
predictable file name under that directory.

Thanks,
Florian