From df52bb5ca1399988284848991ef46c1d00d0030c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Janiszewski?= <janisozaur@gmail.com>
Date: Thu, 1 Oct 2015 18:48:48 +0200
Subject: [PATCH 1/2] Add hooks for Linux

---
 src/hook.c | 42 +++++++++++++++++++++++++++++-------------
 1 file changed, 29 insertions(+), 13 deletions(-)

diff --git a/src/hook.c b/src/hook.c
index 0471ad3037..be83f39dc3 100644
--- a/src/hook.c
+++ b/src/hook.c
@@ -8,18 +8,20 @@
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 3 of the License, or
  * (at your option) any later version.
- 
+
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
- 
+
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *****************************************************************************/
 
 #ifdef _WIN32
-#include <windows.h>
+	#include <windows.h>
+#else
+	#include <sys/mman.h>
 #endif // _WIN32
 #include "hook.h"
 #include "platform/platform.h"
@@ -28,7 +30,6 @@ void* g_hooktableaddress = 0;
 int g_hooktableoffset = 0;
 int g_maxhooks = 1000;
 
-#ifdef _WIN32
 void hookfunc(int address, int newaddress, int stacksize, int registerargs[], int registersreturned, int eaxDestinationRegister)
 {
 	int i = 0;
@@ -96,7 +97,7 @@ void hookfunc(int address, int newaddress, int stacksize, int registerargs[], in
 	data[i++] = 0x00;
 	data[i++] = 0x00;
 	data[i++] = 0x00;
-	
+
 	int sizec = i;
 
 	data[i++] = 0x8B; // push eax, [esp]  - puts eip in eax
@@ -140,7 +141,7 @@ void hookfunc(int address, int newaddress, int stacksize, int registerargs[], in
 	if (!(registersreturned & EDI)) {
 		data[i++] = 0x57; // push edi
 	}
-	
+
 	data[i++] = 0x83; // sub esp, x
 	data[i++] = 0xEC;
 	data[i++] = 4 + (stacksize * 4) + rargssize;
@@ -210,18 +211,31 @@ void hookfunc(int address, int newaddress, int stacksize, int registerargs[], in
 	if (!(registersreturned & EAX)) {
 		data[i++] = 0x58; // pop eax
 	}
-	
+
 	data[i++] = 0xC3; // retn
 
+#ifdef _WIN32
 	WriteProcessMemory(GetCurrentProcess(), (LPVOID)address, data, i, 0);
-}
+#else
+	// We own the pages with PROT_WRITE | PROT_EXEC, we can simply just memcpy the data
+	memcpy((void *)address, data, i);
 #endif // _WIN32
+}
 
 void addhook(int address, int newaddress, int stacksize, int registerargs[], int registersreturned, int eaxDestinationRegister)
 {
-#ifdef _WIN32
 	if (!g_hooktableaddress) {
-		g_hooktableaddress = VirtualAllocEx(GetCurrentProcess(), NULL, g_maxhooks * 100, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
+		size_t size = g_maxhooks * 100;
+#ifdef _WIN32
+		g_hooktableaddress = VirtualAllocEx(GetCurrentProcess(), NULL, size, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
+#else
+		g_hooktableaddress = mmap(NULL, size, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+		if (g_hooktableaddress == MAP_FAILED)
+		{
+			perror("mmap");
+			exit(1);
+		}
+#endif // _WIN32
 	}
 	if (g_hooktableoffset > g_maxhooks) {
 		return;
@@ -232,10 +246,12 @@ void addhook(int address, int newaddress, int stacksize, int registerargs[], int
 	data[i++] = 0xE9; // jmp
 	*((int *)&data[i]) = hookaddress - address - i - 4; i += 4;
 	data[i++] = 0xC3; // retn
+#ifdef _WIN32
 	WriteProcessMemory(GetCurrentProcess(), (LPVOID)address, data, i, 0);
+#else
+	// We own the pages with PROT_WRITE | PROT_EXEC, we can simply just memcpy the data
+	memcpy((void *)address, data, i);
+#endif // _WIN32
 	hookfunc(hookaddress, newaddress, stacksize, registerargs, registersreturned, eaxDestinationRegister);
 	g_hooktableoffset++;
-#else
-	STUB();
-#endif // _WIN32
 }

From 9a1e88872f91c66540e4f51f3996d9fcbf4b9138 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Janiszewski?= <janisozaur@gmail.com>
Date: Thu, 1 Oct 2015 18:57:45 +0200
Subject: [PATCH 2/2] sub_6E7FF3 no longer causes problems

---
 src/interface/viewport.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/src/interface/viewport.c b/src/interface/viewport.c
index 5ec11bf5a4..11175a52d6 100644
--- a/src/interface/viewport.c
+++ b/src/interface/viewport.c
@@ -271,11 +271,7 @@ void sub_689174(sint16* x, sint16* y, sint16 *z)
 
 void sub_6E7FF3(rct_window *w, rct_viewport *viewport, int x, int y)
 {
-#ifdef _WIN32
 	RCT2_CALLPROC_X(0x006E7FF3, 0, 0, 0, x, (int)viewport, (int)w, y);
-#else
-	STUB();
-#endif // _WIN32
 
 //	int zoom = 1 << viewport->zoom;
 //	if (w >= RCT2_GLOBAL(RCT2_ADDRESS_NEW_WINDOW_PTR, rct_window*)){