User:Nosoop/Guide/Advanced - Revision history

Nosoop at 13:45, 23 May 2025

2025-05-23T13:45:19Z

Nosoop: /* Virtual Hook or Detour? */ Add note on symbol aliasing

2024-06-11T04:19:22Z

‎Virtual Hook or Detour?: Add note on symbol aliasing

Nosoop: /* SDKCall Order */ Add missing variable in example

2023-06-01T08:30:42Z

‎SDKCall Order: Add missing variable in example

Nosoop: /* Calling Game Functions */ Add section on whether to set up function calls using signatures or offsets

2023-06-01T08:28:05Z

‎Calling Game Functions: Add section on whether to set up function calls using signatures or offsets

Nosoop: Add primer on gamedata

2023-05-08T09:18:50Z

Add primer on gamedata

Nosoop: /* SDKCall Order */ Put return buffer items into a list; add notes on string return

2023-04-16T10:39:25Z

‎SDKCall Order: Put return buffer items into a list; add notes on string return

Nosoop: /* The Easy Way */ Add note on differing signatures between disassembler scripts

2023-02-05T07:11:46Z

‎The Easy Way: Add note on differing signatures between disassembler scripts

Nosoop: /* The Hard Way */ Add note on visibility of opcodes in IDA

2023-02-05T07:06:00Z

‎The Hard Way: Add note on visibility of opcodes in IDA

Nosoop: /* The Easy Way */ Update Ghidra script link to copy in SourceMod repo

2023-02-05T05:47:59Z

‎The Easy Way: Update Ghidra script link to copy in SourceMod repo

Nosoop: /* Finding Addresses */ Add note on how FindLocation would work

2023-02-04T12:51:02Z

‎Finding Addresses: Add note on how FindLocation would work

@@ Line 107: / Line 107: @@
 == The Easy Way ==
-If you're using IDA (including Free), use the [https://github.com/alliedmodders/sourcemod/blob/master/tools/ida_scripts/makesig7.idc <code>makesig7.idc</code>] script. If you're using Ghidra, use [https://github.com/alliedmodders/sourcemod/blob/master/tools/ghidra_scripts/makesig.py <code>makesig.py</code>].
+If you're using IDA (including Free), use the [https://github.com/alliedmodders/sourcemod/blob/master/tools/ida_scripts/makesig7.idc <code>makesig7.idc</code>] script. If you're using Ghidra, use [https://github.com/alliedmodders/sourcemod/blob/master/tools/ghidra_scripts/makesig.py <code>makesig.py</code>].  (Click those filenames to download the respective scripts.)
 They generally do pretty well at finding and masking byte signatures, but when it fails or you want a more robust signature, you should understand how to create the signatures manually.

← Older revision		Revision as of 04:19, 11 June 2024
Line 192:		Line 192:
	* DHooks provides the bookkeeping on which instances are and aren't hooked, so for virtual hooks the callback will only be invoked on those you specifically hook. On detours, you have to filter on instances yourself.		* DHooks provides the bookkeeping on which instances are and aren't hooked, so for virtual hooks the callback will only be invoked on those you specifically hook. On detours, you have to filter on instances yourself.
	* On chained inheritance, a virtual hook will only act on the exact class and not any parent nor subclasses, even if they all point to the same virtual function. Detours will, again, be called on any invocation of the function, including calls to it made by its subclass.		* On chained inheritance, a virtual hook will only act on the exact class and not any parent nor subclasses, even if they all point to the same virtual function. Detours will, again, be called on any invocation of the function, including calls to it made by its subclass.
		+	* On some binaries (especially with more aggressive optimizations in place), multiple function symbols may map to the same place in memory if they output the same code. As a result, detours may be called when you don't expect them to be.

@@ Line 166: / Line 166: @@
 // bool CGlobalEntityList::IsEntityPtr(void* pTest) -- SDKCall_EntityList is used, so no 'this' explicitly needed
 // SDKCall passes the return value from the called function as its return value, so use an assignment operator
 bool result = SDKCall(g_hSDKCall, pTest);
 </pre>

@@ Line 168: / Line 168: @@
 bool result = SDKCall(g_hSDKCall, pTest);
 </pre>
 = Hooking Game Functions (with DHooks) =

← Older revision		Revision as of 09:18, 8 May 2023
Line 2:		Line 2:

	It's assumed that you're comfortable with programming and various terms. By the end of this page you'll have some knowledge of calling / hooking arbitrary functions in the game.		It's assumed that you're comfortable with programming and various terms. By the end of this page you'll have some knowledge of calling / hooking arbitrary functions in the game.
		+
		+	= What is gamedata? =
		+
		+	''Gamedata'', also known as game data, gameconfig, and gameconf, are files used to specify information tied to a specific game.
		+
		+	As the games that SourceMod runs on are updated independently of SourceMod itself, gamedata is used as a unified way to keep plugins and extensions up to date on game changes without needing to recompile them.

	= Finding Functions =		= Finding Functions =

@@ Line 143: / Line 143: @@
 #* The function was declared as static, where there is no <tt>this</tt> to pass in.
 #* The function was declared with the <tt>SDKCall_GameRules</tt> or <tt>SDKCall_EntityList</tt> call types; SDKTools itself will provide the appropriate global instance.
-# The return buffer.  If the function returns a <tt>Vector</tt> or <tt>QAngle</tt>, the parameter is a <tt>float[3]</tt>.  If the function returns a <tt>char*</tt>, the parameters should be a <tt>char[]</tt> buffer and an <tt>int</tt> specifying the size of the buffer.  If the function returns a primitive type / entity / edict, it will be the return value of the SDKCall, so no such return buffer is necessary.
+# The return buffer, if applicable.
 # Any remaining parameters for the function.

@@ Line 104: / Line 104: @@
 They generally do pretty well at finding and masking byte signatures, but when it fails or you want a more robust signature, you should understand how to create the signatures manually.
 It's exceedingly rare, but possible that the binary has two copies of the exact same short function (for example, when they are typechecked and statically casted to different subclasses). Both scripts will fail in that case. SourceMod's signature scanner will use the first match it finds, so if any match is acceptable, you can still use an appropriately masked signature.
-Be sure to look at the disassembly to make sure that the functions are indeed the same.
+If two copies of a function seem to exist, be sure to look at the disassembly to make sure that the functions are indeed the same.
 = Finding Addresses =

← Older revision		Revision as of 07:06, 5 February 2023
Line 55:		Line 55:

	After you've found a function, you need to tell SourceMod the sequence of bytes unique to it. Those bytes make up a ''signature''.		After you've found a function, you need to tell SourceMod the sequence of bytes unique to it. Those bytes make up a ''signature''.
		+
		+	{{Note\|If you're using IDA and only see the mnemonics in the "IDA View" tab, make sure to set the number of opcode bytes in IDA options to a non-zero number. 8 is sufficient in most cases.}}

	You could treat just the sequence bytes as the signature directly, but this would break very easily whenever the game is updated. At the machine-code level, the ''instructions'' might be the same for "move X to Y", but the ''data'' might change — X and Y might be in a different location in the binary altogether. For an example within a longer signature:		You could treat just the sequence bytes as the signature directly, but this would break very easily whenever the game is updated. At the machine-code level, the ''instructions'' might be the same for "move X to Y", but the ''data'' might change — X and Y might be in a different location in the binary altogether. For an example within a longer signature:

@@ Line 118: / Line 118: @@
 <pre class="cpp">// start from an address
 uintptr_t addr = FindLocation("some_signature");
 addr = *reinterpret_cast<uintptr_t*>(addr + 40); // gameconf: "read" "40"