cellSaveData: Check filename format of savedata files

[elad335]

Offhanded yet loyal to proper PS3 emulation semantics fix for the problem mentioned in #11501.
PS3 savedata filenaming format is fortunately pretty limited. Only uppercase A-Z, _, space, dot and - are allowed. And only if fitting the notorious 8.3 naming length constraints.

[nastys]

Unfortunately, it doesn't fix #11501 (at least on macOS)

[elad335]

what is the content of your savedata?

[nastys]

% ls -al@
total 3840
drwxrwxrwx  1 nastys  staff  131072  6 Feb 23:28 .
drwxrwxrwx  1 nastys  staff  131072 12 Gen 23:48 ..
-rwxrwxrwx  1 nastys  staff    4096  7 Feb 16:52 ._PARAM.PFD
-rwxrwxrwx  1 nastys  staff    4096  7 Feb 16:48 ._PARAM.SFO
-rwxrwxrwx  1 nastys  staff    4096  7 Feb 13:27 ._SYSTEM.DAT
-rwxrwxrwx  1 nastys  staff   80968  6 Feb 23:28 ICON0.PNG
-rwxrwxrwx@ 1 nastys  staff   32768  6 Feb 23:33 PARAM.PFD
	com.apple.lastuseddate#PS	    16 
-rwxrwxrwx@ 1 nastys  staff    2736  6 Feb 23:28 PARAM.SFO
	com.apple.lastuseddate#PS	    16 
-rwxrwxrwx  1 nastys  staff  396540  6 Feb 23:28 PIC1.PNG
-rwxrwxrwx@ 1 nastys  staff  328944  6 Feb 23:33 SYSTEM.DAT
	com.apple.lastuseddate#PS	    16 

[elad335]

The "._" prefixed ones are valid as PS3 savedata files, it may honestly need user modification because it is already user modified. Maybe a warning or semething should be shown idk.

[MSuih]

While they could be valid we don't have any indication of them ever being used by the real console. Same deal as with using nul as filename or having two files with same name but different case. The problem is that this isn't caused by user modification, it is from system modification and it might be hard for user to remove those files or prevent them from being created.

The only way to "properly" fix cases like these is implement our own file system and just show it as a binary blob to the host OS. But I don't think anyone wants to do that and thus the best solution we can do is to add workarounds for individual cases such as these.

[nastys]

How about checking the file contents?
e.g. all resource forks start with 00 05 16 07 00 02 00 00 4D 61 63 20 4F 53 20 58, I believe, and the magic number for .DS_Store is on Wikipedia.
If it's a match, exclude it and/or warn.
Or just add an option that can be toggled per-game.

[nastys]

For reference, I've updated #11501 with magic number checks.

[elad335]

*.DS_Store, desktop.ini, Thumbs.db etc are hidden in this pr. Just the peculiar ._ prefixed stuff are unhidden because they might be valid PS3 savedata, and no amount of data checks will change it. It just need at best to warn users on macOS when such files are found.

[Megamouse]

nani?

[elad335]

rpcs3/rpcs3/Emu/Cell/Modules/cellSaveData.cpp

Line 1510 in 266b605

statGet->sysSizeKB = 35; // always reported as 35 regardless of actual file sizes

[Megamouse]

So why not add a comment or whatever

[elad335]

Done