[Python-Dev] Python 2.5.1 (original) (raw)

Kristján Valur Jónsson kristjan at ccpgames.com
Tue May 1 15:50:30 CEST 2007

Hm, I fail to see the importance of a special regression test for that peculiar file then with its special magical OS properties. Why not focus our attention on real, user generated files?.

-----Original Message-----

Wow, I'm very sorry, I didn't realize how much special pagefile.sys and hiberfil.sys are. As it turns out, even if you create a file with no sharing allowed, you can still open it with backup semantics in other processes, and thus can use GetFileAttributesEx, GetFileTime, etc. The file pagefile.sys seems almost magical then, I don't understand how it's opened to behave like that. The difference is also immediately visible if you try to open Properties of pagefile.sys, you won't even see Security tab there (even when I create file something.txt and then remove all ACLs, including SYSTEM, I can't access the file, but I can see Security tab and can grant myself permissions back), it looks like all kinds of opening that file are denied. Maybe this is a special security feature, so that no process could access swapped pages (otherwise it could be possible with backup semantics). Thus you can't access the file itself, you can only access containing directory.

So I guess we need continue using pagefile.sys as a test case.

Seems to be true, it's just maybe it shouldn't be hardcoded to C:
There's REG_MULTI_SZ PagingFiles in "HKLM\System\CurrentControlSet\Control\Session Manager\Memory Management", btw. The format seems to be "filename minmbsize maxmbsize" for every line.

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