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56 lines
2.9 KiB
Plaintext
56 lines
2.9 KiB
Plaintext
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HFS Release Notes
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First created on: 6/22/92 7:44:55 PM
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----------------------------------------------------------•----------------------------------------------------------
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6/22/92 7:45:06 PM
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File: FileMgrPatches.a,58
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Owner: Chris Derossi
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Project: MainProj∫OS∫HFS∫
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Radar bug: #100889,1032495
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> Release notes for this change:
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Retrospect Remote and QuicKeys both patch low-level Event Manager traps to get time. If
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their trap patches happen to execute when the System (like the Process Manager) is
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calling the Event Manager, then the Macintosh is in “System Mode” when they run. If their
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patches execute at other times, the Mac is not in System Mode.
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If their patches open files while the Mac is in System Mode, then the file they opened is
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marked as “Opened by the System”. This is done so the system can know which files it
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opened versus which files were opened by applications. (There are many reasons for this.
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For example, when an application quits, the Process Manager closes all files that were
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opened by that application and left open.)
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There is a system patch to _Close which prevents files “Opened by the System” from being
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closed by processes other than the system (like applications). In other words, our patch
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to _Close prevents files that the system wants open from being closed by an application.
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The only problem is that under System 7.0 and 7.0.1, our patch to _Close had a bug and
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didn’t work. This meant that anyone could close a file that was opened by the system.
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We fixed the patch to _Close so that applications could no longer close System-opened
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files.
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Both QuicKeys and Retrospect Remote rely on being able to open and close files. All of
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their file operations happen during trap patches to the Event Manager. These patches are
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executed in System Mode sometimes and not in System mode at other times depending on the
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other things the Mac is doing. If a file is opened when the Mac is in System mode, and
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closed when the Mac is not in System mode, then the close fails, leaving the file open.
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This is why QuicKeys and Retrospect Remote are broken.
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Since the patch to _Close has been broken since 7.0, and everyone is living with it that
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way, I disabled it for Cube-E. Conceptually it’s a good idea to prevent non-System
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processes from closing files opened by the System, but I don’t know of any dependencies
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on that behavior. So the bottom line is that anyone can once again close files that were
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opened by the System and QuicKeys and Retrospect Remote work again.
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> What was tested:
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I have a reproducable case of the QuicKeys failure that now works correctly. I didn’t do
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any real testing of Retrospect because the bug is random, depending on exactly when the
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trap patches fire. However, the frequent occurance of files being left open hasn’t
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happened in several days. (It used to happen nightly).
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----------------------------------------------------------•----------------------------------------------------------
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