Re: Start application & continue after app exits

Mike Meyer wrote: 
"guy lateur" <guy.lateurNNOOSSPPAAMM@xxxxxxxxxx> writes:


Also note that this method of creating tempfiles is technically unsafe,
as it is theoretically possible that another process would create a file
of the same name in the same directory and then try to use it, resulting
in a race condition between the two processes. This is practically
unlikely, however, and I'm a pragmatist.

I see what you mean, but wouldn't a call to open(fn, 'w') on a filename that's in use (for reading or writing) result in an error condition or something? I'm a noob, btw. 


Not necessarily - it depends on the OS. Unix is quite happy to let
multiple processes read/write a file at the same time.

FWIW, this also means that the methodology as outlined is
insecure. Some other program can read the temporary file as it exists
on the disk, thus disclosing it's contents to unauthorized readers.

Right. So we are all adults here and if that matters to your application you've got to find a different way, perhaps by using

tmpFile = tempfile.NamedTemporaryFile()

instead of

tmpFile = tempfile.mktemp()

and

os.spawnlp(os.P_WAIT, "winword.exe", "winword.exe", tmpFile.name)

instead of

os.system("winword.exe %s" % tmpFile)

but I don't think all (if any) versions of Windows can handle opening that file while we are holding it open already. And I guess it still doesn't make it secure because the file exists on disk and can be read.

So I stand by my prior, simpler solution, that will work portably and reliably for all practical purposes, purposeful maliciousness excepted. If you are worried about security, you would't be saving the file to the temp directory in plain text anyway.

If there is a portable, reliable, secure, and simple solution that I've overlooked, however, I'm all ears. :)

Now, if the OP's requirement is specifically for winword on Windows, a more specific approach could be used that doesn't involve saving any temporary files at all, such as by using COM automation to build the document. But I hate nonportable solutions! :)

--
Paul McNett
http://paulmcnett.com

.

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