[midwan]

Summary

Quitting Opus no longer throws out system patches that other programs installed after it. Until now, with Sysmon's SysInfo.library on the system, the machine could freeze or reboot soon after Opus quit. dopus5.library now restores only the vectors that still point to it, and leaves its own function in a chain someone else has patched since, passing calls through.

Issue

Fixes #231

The freeze in the original report was a stack overflow in aatext.library, fixed in aatext.library 1.1. While tracking it down, the AAText author found this second problem: L_WB_Remove_Patch() wrote the saved vectors back without checking them.

Changes

• Later patches survive Opus quitting. The clock task opens SysInfo.library for the CPU display. Sysmon's SysInfo loads sysmon.library, which patches 16 exec vectors on top of Opus, AddTask/RemTask/FindTask among them. When dopus5.library closed, it wrote its saved AddTask/RemTask/FindTask vectors back over sysmon's and left the other 13 in place. The next task start hung the machine. Now each vector is checked: if it still points to Opus it is restored, otherwise the newer patch is put back and the Opus function stays in the chain.
• Pass-through patches. Patch state (wb_old_function, wb_patch_base, wb_patch_flags) moves out of LibData into static arrays, because a patch left in a chain must keep working after the library data is freed. Every patch function starts with a check: when Opus is not running the patch, the call goes straight to the next function and touches no library data. Removal switches the patches off, waits on usecount for calls already running inside them, and only then changes vectors.
• The library stays loaded while a patch is left in a chain. LibExpunge/LibClose refuse to unload the segment while wb_patches_installed() is true. The next Opus start reuses the resident library and switches the patch back on instead of installing it a second time. In that case a newer dopus5.library on disk only loads after a reboot.
• Original*() without patches. OriginalOpen() and the other DOS/icon bypass calls use the plain system function when the patch is not running. With dopus/NoSysPatch set, OriginalRelabel(), DeleteIcon(), and WriteIcon() before icon.library V44, read a patch table that was never allocated.
• OS4: the OpenWorkbenchObject() patch returned FALSE even when the object was opened.
• The unused #else removal branch is gone; its "reinstall" path set old_function[] instead of the patch.

The atomic usecount helpers move from three copies into wb.h and gain a compiler barrier on OS3, so the patch state is read after the count goes up. The revision bump is left to the release, as in recent PRs.

Affected platforms

• AmigaOS 3 (os3)
• AmigaOS 3 / 68000 (os3-68000)
• AmigaOS 4 (os4)
• MorphOS (mos)
• AROS i386 (i386-aros)
• AROS x86_64 (x86_64-aros)
• AROS aarch64 (aarch64-aros)

Verification

Runtime checks ran on the A4000 OS 3.2 Amiberry config (68060), with Sysmon 1.20a's SysInfo.library and a probe that dumps exec LVOs -30 to -330 and classifies each vector as ROM, dopus5.library or sysmon.library. The script started Opus, quit it with command quit force, called RemLibrary() on dopus5.library, opened bullet and TrueType fonts, then started and quit Opus a second time.

	5.104-era library (73.6)	This branch
AddTask/RemTask/FindTask after quit	back to pre-sysmon values; other 13 still sysmon	all 16 still sysmon
dopus5.library after RemLibrary()	unloaded	stays loaded
Opus started again	machine hung	starts, quits, script finishes
Without Sysmon	vectors restored, library unloads	same

• Calibri fails to open on this system in both runs. It is a font setup problem, unrelated to this change.
• Builds: dopus5.library for OS3 (pinned CI image), OS4, MorphOS and AROS i386/x86_64/aarch64. No new warnings against master; MorphOS has 6 fewer (_ATOMIC_ADD pointer sign).

Checklist

• CI is green (or expected failures are explained).
• ChangeLog updated with a [dopus5 next] entry.
• documents/DOpus5.guide updated and @$VER bumped if user-visible
  behaviour changed. (No documented behaviour changes.)
• Relevant *_REVISION in source/Include/dopus/version.h bumped if
  a versioned binary changed. (Left for the release.)
• No new compiler warnings introduced on any platform.
• No drive-by reformatting of unrelated code.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-26T21:54:26.798482Z	8aa6910	PR opened

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