Support boot-arg -dbgenhiolog to redirect IOLog output to kernel vp…

…rintf
acidanthera · Dec 6, 2021 · 1b50f48 · 1b50f48
1 parent b4813da
commit 1b50f48
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Showing 5 changed files with 28 additions and 3 deletions.
diff --git a/Changelog.md b/Changelog.md
@@ -1,5 +1,8 @@
 DebugEnhancer Changelog
 ============================
+#### v1.0.5
+- Support boot-arg `-dbgenhiolog` to redirect IOLog output to kernel vprintf
+
 #### v1.0.4
 - Use method routeMultipleLong instead of routeMultiple in order to avoid conflict with HibernationFixup
 

diff --git a/DebugEnhancer/kern_dbgenhancer.cpp b/DebugEnhancer/kern_dbgenhancer.cpp
@@ -88,6 +88,16 @@ uint32_t DBGENH::hibernate_write_image(void)
 
 //==============================================================================
 
+void DBGENH::IOLog(const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	callbackDBGENH->kern_vprintf(fmt, ap);
+	va_end(ap);
+}
+
+//==============================================================================
+
 void DBGENH::processKernel(KernelPatcher &patcher)
 {
 	if (!(progressState & ProcessingState::KernelRouted))
@@ -111,9 +121,13 @@ void DBGENH::processKernel(KernelPatcher &patcher)
 				{"_kdb_printf", kdb_printf},
 				{"_kprintf", kprintf},
 				{"_hibernate_write_image", hibernate_write_image, org_hibernate_write_image},
-				{"_IOHibernateSystemSleep", IOHibernateSystemSleep, orgIOHibernateSystemSleep}
+				{"_IOHibernateSystemSleep", IOHibernateSystemSleep, orgIOHibernateSystemSleep},
+				{"_IOLog", IOLog, orgIOLog}
 			};
-			if (!patcher.routeMultipleLong(KernelPatcher::KernelID, requests, arrsize(requests)))
+
+			bool route_iolog = checkKernelArgument("-dbgenhiolog");
+			size_t size = arrsize(requests) - (route_iolog ? 0 : 1);
+			if (!patcher.routeMultipleLong(KernelPatcher::KernelID, requests, size))
 				SYSLOG("DBGENH", "patcher.routeMultiple for %s is failed with error %d", requests[0].symbol, patcher.getError());
 		} else
 			SYSLOG("DBGENH", "Symbol _vprintf cannot be resolved with error %d", patcher.getError());

diff --git a/DebugEnhancer/kern_dbgenhancer.hpp b/DebugEnhancer/kern_dbgenhancer.hpp
@@ -30,13 +30,15 @@ class DBGENH {
 	static void			kprintf(const char *fmt, ...);
 	static IOReturn     IOHibernateSystemSleep(void);
 	static uint32_t	    hibernate_write_image(void);
+	static void         IOLog(const char *fmt, ...);
 
 	/**
 	 *  Trampolines for original method invocations
 	 */
 
 	mach_vm_address_t orgIOHibernateSystemSleep {};
 	mach_vm_address_t org_hibernate_write_image {};
+	mach_vm_address_t orgIOLog {};
 
 	/**
 	 *  Original method

diff --git a/DebugEnhancer/kern_start.cpp b/DebugEnhancer/kern_start.cpp
@@ -13,7 +13,7 @@
 static DBGENH dbgenh;
 
 static const char *bootargOff[] {
-	"-dbgenhxoff"
+	"-dbgenhoff"
 };
 
 static const char *bootargDebug[] {

diff --git a/README.md b/README.md
@@ -5,3 +5,9 @@ DebugEnhancer
 
 A Lilu plugin intended to enable debug output in the macOS kernel,
 the original idea belongs to Piker-Alpha, see https://github.com/Piker-Alpha/debugMachKernel.sh for more details.
+
+#### Boot-args
+- `-dbgenhdbg`   turns on debugging output
+- `-dbgenhbeta`  enables loading on unsupported osx
+- `-dbgenhoff`   disables kext loading
+- `-dbgenhiolog` redirect IOLog output to kernel vprintf (the same as for kdb_printf and kprintf)