From 414c97446c4bfa635e2d2aac2f6085b976b5e9cd Mon Sep 17 00:00:00 2001
From: vit9696 <vit9696@users.noreply.github.com>
Date: Thu, 21 Nov 2019 19:19:56 +0300
Subject: [PATCH] Added support for per-process (LocalOnly) userspace patches

---
 Changelog.md               |  1 +
 Lilu/Headers/kern_user.hpp | 13 +++++++++++++
 Lilu/Sources/kern_user.cpp |  4 ++++
 3 files changed, 18 insertions(+)

diff --git a/Changelog.md b/Changelog.md
index befcdc35..701bd354 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -3,6 +3,7 @@ Lilu Changelog
 #### v1.4.0
 - Fixed mishandling user patches process list after processKernel API call
 - Fixed extra I/O in user patcher even when no patches were needed
+- Added support for per-process (LocalOnly) userspace patches
 
 #### v1.3.9
 - Added QEMU/KVM vendor compatibility to device detection logic
diff --git a/Lilu/Headers/kern_user.hpp b/Lilu/Headers/kern_user.hpp
index 11e3ec96..db9890a3 100644
--- a/Lilu/Headers/kern_user.hpp
+++ b/Lilu/Headers/kern_user.hpp
@@ -88,11 +88,22 @@ class UserPatcher {
 		"__common"
 	};
 
+	/**
+	 * Binary modification patches flags
+	 */
+	enum BinaryModPatchFlags {
+		/*
+		 * Only applies to one process, not globally.
+		 */
+		LocalOnly = 1
+	};
+
 	/**
 	 *  Structure holding lookup-style binary patches
 	 */
 	struct BinaryModPatch {
 		cpu_type_t cpu;
+		uint32_t flags;
 		const uint8_t *find;
 		const uint8_t *replace;
 		size_t size;
@@ -102,6 +113,8 @@ class UserPatcher {
 		uint32_t section;
 	};
 
+	static_assert(sizeof(BinaryModPatch) == 56, "BinaryModPatch ABI compatibility failure");
+
 	/**
 	 *  Structure describing the modifications for the binary
 	 */
diff --git a/Lilu/Sources/kern_user.cpp b/Lilu/Sources/kern_user.cpp
index 27c2d89c..fc545f53 100644
--- a/Lilu/Sources/kern_user.cpp
+++ b/Lilu/Sources/kern_user.cpp
@@ -219,6 +219,10 @@ void UserPatcher::performPagePatch(const void *data_ptr, size_t data_size) {
 						auto &rpatch = storage->mod->patches[ref->i];
 						sz = ref->pageOffs.size();
 
+						// Skip patches that are meant to apply only to select processes.
+						if (rpatch.flags & LocalOnly) {
+							continue;
+						}
 
 						DBGLOG("user", "found what we are looking for %X %X %X %X %X %X %X %X", rpatch.find[0],
 								rpatch.size > 1 ? rpatch.find[1] : 0xff,