Short: Safer Setfunctions Debug Tools Author: thor@math.tu-berlin.de (Thomas Richter) Uploader: thor@math.tu-berlin.de (Thomas Richter) Version: 2.08 Type: dev/debug Requires: An Amiga, every model, every OS will do _____________________________________________________________________________ The THOR-Software Licence This License applies to the computer programs known as "SaferPatches" and "ShowPatch". The "Program", below, refers to such program. The programs and files in this distribution are freely distributable under the restrictions stated below, but are also Copyright (c) Thomas Richter. Distribution of the Program by a commercial organization without written permission from the author to any third party is prohibited if any payment is made in connection with such distribution, whether directly (as in payment for a copy of the Program) or indirectly (as in payment for some service related to the Program, or payment for some product or service that includes a copy of the Program "without charge"; these are only examples, and not an exhaustive enumeration of prohibited activities). However, the following methods of distribution involving payment shall not in and of themselves be a violation of this restriction: (i) Posting the Program on a public access information storage and retrieval service for which a fee is received for retrieving information (such as an on-line service), provided that the fee is not content-dependent (i.e., the fee would be the same for retrieving the same volume of information consisting of random data). (ii) Distributing the Program on a CD-ROM, provided that the files containing the Program are reproduced entirely and verbatim on such CD-ROM, and provided further that all information on such CD-ROM be redistributable for non-commercial purposes without charge. Everything in this distribution must be kept together, in original and unmodified form. Limitations. THE PROGRAM IS PROVIDED TO YOU "AS IS," WITHOUT WARRANTY. THERE IS NO WARRANTY FOR THE PROGRAM, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. IF YOU DO NOT ACCEPT THIS LICENCE, YOU MUST DELETE ALL FILES CONTAINED IN THIS ARCHIVE. _____________________________________________________________________________ Purpose of this program: Make the SetFunction (= patch function) of the OS safer, allow installation and removal of patches in any order. Record the patches made and the program that made the patch. This program is mainly intended as a debugging tool, for recording the patches installed and to capture illegal patches. It is, however, adviced to run with SaferPatches installed permanently. SaferPatches will free the additional memory occupied by the patched functions automatically if a library is flushed later on. SYNOPSIS: SaferPatches INSTALL REMOVE REMEMBER WARN INSTALL Add the "SaferPatches" patch to the system. REMOVE Remove "SaferPatches" from the system. You are, however, "recommanded" not to remove it once you've started it. REMEMBER This option can be given together with INSTALL. If present, SaferPatches will store the names of the programs together with the patch they added. WARN Saferpatches will guru with 0x10000026 if a removed vector is still used. SYNOPSIS: ShowPatch fd_dir Shows all patches added to the system, together with the entry point and the program that added the patch, if available - see the REMEMBER option of the Saferpatches program. If the "fd_dir" is given, ShowPatch will read standard ".fd" library descriptions from that subdirectory and will present the name of the entry point that has been patched as well. _____________________________________________________________________________ Compatibility: "SaferPatches" is NOT compatible to the following illegal patches: (see below for what is considered to be legal) -CEDPatch The way "SaferPatches" operates conflicts with my debug utility "MemSniff". If you want to run both, "MemSniff" and "SaferPatches", you should add the command line option "SNIFF" to SaferPatches. You shouldn't provide that option in other situations. VirusZ might report that libraries got patched from time to time. This is because SaferPatches modifies the Expunge vector of all libraries in order to free the memory occupied by the patches if the library gets closed. This warning message is harmless. IMPORTANT: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Saferpatches MUST be run BEHIND SetPatch !!!!!!!!!!!!!!!!! IMPORTANT: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! SaferPatches IS compatible to the debug tool PatchWork. _____________________________________________________________________________ Gurus: Because "SaferPatches" is supposed to be a debug utility, it may create "guru meditations", i.e. software alerts. The following alerts may be created by SaferPatches: 0x01000020 Patch vector out of range. A program tried to patch a vector in a library that isn't present. 0x01000021 Entry is not patchable. A program tried to install a patch into a vector that can't be patched. Some vectors, like the GetCC() vector of the exec lib are directly inlined functions that can't be changed with SaferPatches. Same goes for the DOS library of releases 32 to 35, but this has changed starting with releases 36 and up of the OS. 0x01000022 No mem for patch vector. SaferPatches failed to allocate memory for the patch. 0x01000023 Patched vector to ROM. A program attempted to patch one ROM vector to a second vector which is actually in the ROM. Replacing one system function by a different one is considered to be illegal. 0x01000024 Found libentry without patches SaferPatches found a library in its patch list that isn't actually patched. This is an internal failure and shouldn't occur. 0x01000025 Unsafe patch A program tried to patch one vector that can't be patched in a safe way because it is called by the SetFunction procedure itself. One example is "SetFunction", or "SumLibrary". 0x01000026 Removed libentry called A libvector that has been removed was illegally called again. A program restored an older patch, but was still calling the obsolete return vector. This can only happen with WARN enabled. 0x01000027 Function pointer is NULL Somebody tried to patch a function to NULL. _____________________________________________________________________________ Legal vs. illegal patching: Three operations are considered to be "legal" patching operations: 1) Install a patch 2) Remove a patch 3) Verify, if a given patch is installed. 3) is new to this implementation of SaferPatches and not having it messed the system with the RTPatch program. A legal way how to install a patch: (with or without SaferPatches) -Call Forbid() or even Disable() in critical cases. -Load the address of the new function in d0, the offset in a0, the library and a1, and ExecBase in a6. -Call SetFunction() -Store the return value of SetFunction as pointer to the old function. -Call Permit() or Enable(). The following methods of installing patches ARE ILLEGAL: -Forgetting to Permit()/Forbid(). -Reading the vector directly from the library vectors instead of using the return value. -Using the return code of SetFunction for anything else except jumping into the old code. -Patching one OS function to a different one. -Patching functions that can't be patched, like inline functions or functions called by SaferPatches. This includes the functions CacheClearU(), SetFunction() and SumLibrary(). -Using anything else but the return code of SetFunction for calling the old function. -Writing the new function directly into the vector offset. A legal way to remove a patch: (with SaferPatches) Even though the procedures presented below remove a patch vector safely from the os (ONLY the vector, NOT the code) IT DOES NOT PREVENT, WITH SAFERPATCHES INSTALLED OR NOT, THAT SOME TASK IS STILL EXECUTING THE CODE OF YOUR PATCH. This is, you may not freely deallocate the memory your patch resides in. Removing patches is always a problem, it is not recommended to release the patch memory at all UNLESS YOU CAN REALLY, ABSOLUTELY ENSURE THAT NO TASK IS EXECUTING YOUR CODE. There is, however, no general guide line how to do that. The following algorithm "works" IF YOU KNOW the patch is installed and SaferPatches is installed. It DOES NOT work around general patch caveats: -Load d0 with the return code of SetFunction you got when installing the patch. Load a1 with the base address of the library. Load a6 with execbase. -Call SetFunction(). A legal and safe way to remove a patch: (with or without SaferPatches) The following mechanism is recommended for general patch removal. Please note THAT THIS MIGHT FAIL and you won't be able to remove your patch at all. It WON'T fail with SaferPatches, though. It does, too, not work around the code memory caveats from above. -Call Forbid() or Disable(). -Call SetFunction() with the same arguments AS IF you are installing the patch again, this is: Load the address of the new function in d0,the library base in a1 and ExecBase in a6 and offset in a0. Call SetFunction. -Check the return code: If this is the entry point of your patch, then: -Load d0 with the return code of SetFunction when installing the patch. Load a1 with the base address of the library. Load a6 with execbase. -Call SetFunction(). These calls will remove your patch. If this is not the address of your patch, then: -Load d0 with THIS return code of SetFunction, i.e. what you got from the call a few lines on top. Load a1 with the base address of the library. Load a6 with execbase. -Call SetFunction(). This will re-install the last patch. YOUR PATCH CAN'T BE REMOVED SAFELY IN THIS CASE (SaferPatches is not running). -Call Permit() or Enable(). The following methods of removing a patch ARE ILLEGAL: -Use anything else but the return code of the installing SetFunction for removing the patch again. -Removing the new function by writing the old return code directly into the vector offset. -Executing the steps above not completely in Forbid() mode, i.e. call Permit() in between or calling any other os function that might break the forbid. A legal way how to verify whether your patch is still installed: This algorithm can be used to check if your patch is still active, using SaferPatches. It will only tell you if the patch is "frontmost" if Safer- Patches is not installed. -Call Forbid() or Disable() -Call SetFunction with the same arguments AS IF you are installing the patch again, this is: Load the address of the new function in d0,the library base in a1 and ExecBase in a6 and offset in a0. Call SetFunction. -Check the return code. If it is the same pointer you passed in d0 to SetFunction, your patch is still active. It has been installed now, by the procedure above and must/can be removed if desired/ required with a second call to SaferPatches. It will NOT be installed twice by this algorithm, neither with nor without SaferPatches. -Call Permit() or Enable(). This method is used by the RTPatch program and also considered to be legal. The following verify methods are considered to be illegal: -Failing to call Forbid(). -Reading the vector entry from the vector base directly. How to check if SaferPatches is installed: -Call FindPort("SetMan"). If the result is non-zero, SaferPatches, SetMan or PatchControl is installed. Do not use this port for anything else. -Call FindPort("SaferPatches.rendezvous"). If the result is non- zero, it's specifically SaferPatches. There's usually no need to to check for this port. Don't use this port for anything else! _____________________________________________________________________________ New in 2.08: Hopefully fixed a minor compatibility problem with PoolMem and MuGuardian- Angel. _____________________________________________________________________________ New in 2.07.1: Updated the ReadMe a bit. New in 2.07: Added another GURU, added the WARN option to turn off the 0x01000026 guru. Patched the close function for completeness (forgot again about the delayed expunge function, sigh.). Updates the SHOWPATCH program. Added a SetMan port of completeness. _____________________________________________________________________________ New in 2.06: Added a new GURU and fixed a bug of the Expunge replacement. Thanks to Magnus for reporting! _____________________________________________________________________________ Thomas, May 1998 ============================= Archive contents ============================= Original Packed Ratio Date Time Name -------- ------- ----- --------- -------- ------------- 3496 2294 34.3% 30-May-99 00:37:58 +SaferPatches 13021 4860 62.6% 30-May-99 00:39:12 +SaferPatches.readme 5004 3347 33.1% 09-Nov-97 23:44:56 +ShowPatch -------- ------- ----- --------- -------- 21521 10501 51.2% 31-May-99 22:09:08 3 files