Print actual string arguments with -Xtrace (part 2)

The changes reflect the feature request #16416. Adding cmdline option to specify string argument length. -Xtrace:maxstringlength=[1-128] maxstringlength takes an unsigned integer value from 1 to 128 If maxstringlength = 0 or unspecified, default to address printing. Other invalid inputs result in the input error. There will be subsequent PR for tests (part 3). Signed-off-by: Nick Kamal <[email protected]>
eclipse-openj9 · Dec 10, 2024 · 956106f · 956106f
1 parent 4ee9b77
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Showing 6 changed files with 65 additions and 15 deletions.
diff --git a/runtime/oti/j9trace.h b/runtime/oti/j9trace.h
@@ -63,12 +63,19 @@ typedef struct RasGlobalStorage {
 	void *  traceMethodTable;
 	int     stackdepth;
 	unsigned int    stackCompressionLevel;
+	unsigned int    maxStringLength;
 	ConfigureTraceFunction configureTraceEngine;
 #if defined(J9VM_OPT_CRIU_SUPPORT)
 	CRIURestoreInitializeTrace criuRestoreInitializeTrace;
 #endif /* defined(J9VM_OPT_CRIU_SUPPORT) */
 } RasGlobalStorage;
 
+/*
+ * Default and maximum values for RasGlobalStorage.maxStringLength.
+ */
+#define RAS_MAX_STRING_LENGTH_DEFAULT  32
+#define RAS_MAX_STRING_LENGTH_LIMIT   128
+
 #define RAS_GLOBAL(x) ((RasGlobalStorage *)thr->javaVM->j9rasGlobalStorage)->x 
 
 #define RAS_GLOBAL_FROM_JAVAVM(x,vm) ((RasGlobalStorage *)vm->j9rasGlobalStorage)->x

diff --git a/runtime/rasdump/dmpsup.c b/runtime/rasdump/dmpsup.c
@@ -1570,7 +1570,8 @@ J9VMDllMain(J9JavaVM *vm, IDATA stage, void *reserved)
 				/* RAS init may happen in either dump or trace */
 				vm->j9rasGlobalStorage = j9mem_allocate_memory(sizeof(RasGlobalStorage), OMRMEM_CATEGORY_VM);
 				if (vm->j9rasGlobalStorage != NULL) {
-					memset (vm->j9rasGlobalStorage, '\0', sizeof(RasGlobalStorage));
+					memset(vm->j9rasGlobalStorage, '\0', sizeof(RasGlobalStorage));
+					RAS_GLOBAL_FROM_JAVAVM(maxStringLength, vm) = RAS_MAX_STRING_LENGTH_DEFAULT;
 				}
 			}
 			break;

diff --git a/runtime/rastrace/j9rastrace.h b/runtime/rastrace/j9rastrace.h
@@ -54,6 +54,7 @@ extern "C" {
 #define RAS_STACKDEPTH_KEYWORD          "STACKDEPTH"
 #define RAS_SLEEPTIME_KEYWORD           "SLEEPTIME"
 #define RAS_COMPRESSION_LEVEL_KEYWORD   "STACKCOMPRESSIONLEVEL"
+#define RAS_MAX_STRING_LENGTH_KEYWORD   "MAXSTRINGLENGTH"
 
 /*
  * ======================================================================
@@ -128,8 +129,9 @@ void rasTriggerMethod(J9VMThread *thr, J9Method *mb, I_32 entry, const TriggerPh
 BOOLEAN matchMethod (RasMethodTable * methodTable, J9Method *method);
 omr_error_t processTriggerMethodClause(OMR_VMThread *, char *, BOOLEAN atRuntime);
 void doTriggerActionJstacktrace(OMR_VMThread *thr);
-omr_error_t setStackDepth(J9JavaVM *thr, const char * value, BOOLEAN atRuntime);
-omr_error_t setStackCompressionLevel(J9JavaVM * vm, const char *str, BOOLEAN atRuntime);
+omr_error_t setStackDepth(J9JavaVM *thr, const char *value, BOOLEAN atRuntime);
+omr_error_t setStackCompressionLevel(J9JavaVM *vm, const char *str, BOOLEAN atRuntime);
+omr_error_t setMaxStringLength(J9JavaVM *vm, const char *str, BOOLEAN atRuntime);
 
 /*
  * =============================================================================

diff --git a/runtime/rastrace/method_trace.c b/runtime/rastrace/method_trace.c
@@ -476,11 +476,13 @@ traceMethodArgObject(J9VMThread *thr, UDATA* arg0EA, char* cursor, UDATA length)
 	} else {
 		J9Class *clazz = J9OBJECT_CLAZZ(thr, object);
 		J9JavaVM *vm = thr->javaVM;
+		const unsigned int maxStringLength = RAS_GLOBAL_FROM_JAVAVM(maxStringLength, vm);
 
-		if (clazz == J9VMJAVALANGSTRING_OR_NULL(vm)) {
+		if (clazz == J9VMJAVALANGSTRING_OR_NULL(vm)
+			&& (0 != maxStringLength)
+		) {
 			/* string argument */
-#define DEFAULT_STRING_LENGTH 32
-			char utf8Buffer[128];
+			char utf8Buffer[RAS_MAX_STRING_LENGTH_LIMIT + 1];
 			UDATA utf8Length = 0;
 
 			char *utf8String = vm->internalVMFunctions->copyStringToUTF8WithMemAlloc(
@@ -495,16 +497,15 @@ traceMethodArgObject(J9VMThread *thr, UDATA* arg0EA, char* cursor, UDATA length)
 
 			if (NULL == utf8String) {
 				j9str_printf(PORTLIB, cursor, length, "(String)<Memory allocation error>");
-			} else if (utf8Length > DEFAULT_STRING_LENGTH) {
-				j9str_printf(PORTLIB, cursor, length, "(String)\"%.*s\"...", (U_32)DEFAULT_STRING_LENGTH, utf8String);
+			} else if (utf8Length > maxStringLength) {
+				j9str_printf(PORTLIB, cursor, length, "(String)\"%.*s\"...", (U_32)maxStringLength, utf8String);
 			} else {
 				j9str_printf(PORTLIB, cursor, length, "(String)\"%.*s\"", (U_32)utf8Length, utf8String);
 			}
 
 			if (utf8Buffer != utf8String) {
 				j9mem_free_memory(utf8String);
 			}
-#undef DEFAULT_STRING_LENGTH
 		} else {
 			/* TODO: handle arrays */
 

diff --git a/runtime/rastrace/method_trigger.c b/runtime/rastrace/method_trigger.c
@@ -60,7 +60,6 @@ static const StackTraceFormattingFunction stackTraceFormattingFunctions[] = {
 
 #define NUM_STACK_TRACE_FORMATTING_FUNCTIONS (sizeof(stackTraceFormattingFunctions) / sizeof(stackTraceFormattingFunctions[0]))
 
-
 /**************************************************************************
  * name        - rasSetTriggerTrace
  * description - Called whenever a class is loaded.
@@ -547,6 +546,41 @@ decimalString2Int(J9PortLibrary* portLibrary, const char *decString, I_32 signed
 	return num;
 }
 
+/**************************************************************************
+ * name        - setMaxStringLength
+ * description - Set max string length for arguments and return values
+ * parameters  - vm, str - trace options, atRuntime flag
+ * returns     - JNI return code
+ *************************************************************************/
+omr_error_t
+setMaxStringLength(J9JavaVM *vm, const char *str, BOOLEAN atRuntime)
+{
+	PORT_ACCESS_FROM_JAVAVM(vm);
+	int value = 0;
+	int length = 0;
+	omr_error_t rc = OMR_ERROR_NONE;
+	const char *param = NULL;
+
+	if (1 != getParmNumber(str)) {
+		goto err;
+	}
+
+	param = getPositionalParm(1, str, &length);
+
+	value = decimalString2Int(PORTLIB, param, FALSE, &rc);
+	if (OMR_ERROR_NONE != rc) {
+		goto err;
+	}
+
+	if ((1 <= value) && (value <= RAS_MAX_STRING_LENGTH_LIMIT)) {
+		RAS_GLOBAL_FROM_JAVAVM(maxStringLength, vm) = (unsigned int)value;
+		return OMR_ERROR_NONE;
+	}
+err:
+	vaReportJ9VMCommandLineError(PORTLIB, "maxstringlength takes an integer value from 1 to %d", RAS_MAX_STRING_LENGTH_LIMIT);
+	return OMR_ERROR_INTERNAL;
+}
+
 /**************************************************************************
  * name        - addTriggeredMethodSpec
  * description - Take a user specified method trigger rule (from the
@@ -653,13 +687,17 @@ addTriggeredMethodSpec(J9VMThread *thr, const char *ptrMethodSpec, const struct
 			ptr->next = methodRule;
 		}
 
-		if (methodRule->entryAction != NULL && methodRule->entryAction->name != NULL
-		    && j9_cmdla_stricmp((char *)methodRule->entryAction->name, "jstacktrace") == 0) {
+		if ((NULL != methodRule->entryAction)
+			&& (NULL != methodRule->entryAction->name)
+			&& (0 == j9_cmdla_stricmp((char *)methodRule->entryAction->name, "jstacktrace"))
+		) {
 			/* set up the current method spec to be enabled for trace */
 			setMethod(thr->javaVM, ptrMethodSpec, FALSE);
 		}
-		if (methodRule->exitAction != NULL && methodRule->exitAction->name != NULL
-		    && j9_cmdla_stricmp((char *)methodRule->exitAction->name, "jstacktrace") == 0) {
+		if ((NULL != methodRule->exitAction)
+			&& (NULL != methodRule->exitAction->name)
+			&& (0 == j9_cmdla_stricmp((char *)methodRule->exitAction->name, "jstacktrace"))
+		) {
 			/* set up the current method spec to be enabled for trace */
 			setMethod(thr->javaVM, ptrMethodSpec, FALSE);
 		}

diff --git a/runtime/rastrace/trcengine.c b/runtime/rastrace/trcengine.c
@@ -117,9 +117,10 @@ const struct traceOption TRACE_OPTIONS[] =
 	{RAS_METHODS_KEYWORD, FALSE, setMethod},
 	{RAS_STACKDEPTH_KEYWORD, TRUE, setStackDepth},
 	{RAS_COMPRESSION_LEVEL_KEYWORD, TRUE, setStackCompressionLevel},
+	{RAS_MAX_STRING_LENGTH_KEYWORD, FALSE, setMaxStringLength},
 };
 
-#define NUMBER_OF_TRACE_OPTIONS ( sizeof(TRACE_OPTIONS) / sizeof(struct traceOption))
+#define NUMBER_OF_TRACE_OPTIONS (sizeof(TRACE_OPTIONS) / sizeof(struct traceOption))
 
 /**
  * The list of trigger actions defined by J9VM passed to the