Add java backtrace functionality

This commit adds two functions, sprint_java_backtrace() and
print_java_backtrace.  The former returns the java backtrace as one
string (may need to set the -DMAXSTRINGLEN var to read the entire
backtrace), and latter prints the java backtrace one line at a time.

*java/HelperSDT.c - Add METHOD_STAP_BT and _METHOD_BT_DELETE jni
 functions
*java/HelperSDT.h - ditto
*java/..../HelperSDT.java - ditto
*java/stapbm.in - add conditional calls to functions based on backtrace
 flag status
*tapset-method.cxx - add the probe points for METHOD_STAP_BT and
 METHOD_BT_DELETE to be handled
*tapset/java.stp - add sprint_java_backtrace and print_java_backtrace functions

Author: lberk

java/HelperSDT.c

@@ -491,3 +491,29 @@ JNIEXPORT void JNICALL Java_org_systemtap_byteman_helper_HelperSDT_METHOD_1STAP_
     arg10.vartype.c = get_java_string(env, _arg10);
   STAP_PROBE11(HelperSDT, method__10, arg1.vartype.d, arg2.vartype.d, arg3.vartype.d, arg4.vartype.d, arg5.vartype.d, arg6.vartype.d, arg7.vartype.d, arg8.vartype.d, arg9.vartype.d, arg10.vartype.d, rulename);
 }
+
+/*
+ * Class:     HelperSDT
+ * Method:    METHOD_STAP_BT
+ * Signature: (Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;)V
+ */
+JNIEXPORT void JNICALL Java_org_systemtap_byteman_helper_HelperSDT_METHOD_1STAP_1BT
+(JNIEnv *env, jobject obj, jstring _rulename, jstring _exception, jint _counter)
+{
+  char* rulename = get_java_string(env, _rulename);
+  char* excp = get_java_string(env, _exception);
+  int stdepth = _counter;
+  STAP_PROBE3(HelperSDT, method__bt, excp, stdepth, rulename);
+}
+
+/*
+ * Class:     HelperSDT
+ * Method:    METHOD_BT_DELETE
+ * Signature: (Ljava/lang/String;)V
+ */
+JNIEXPORT void JNICALL Java_org_systemtap_byteman_helper_HelperSDT_METHOD_1BT_1DELETE
+(JNIEnv *env, jobject obj, jstring _rulename)
+{
+  char* rulename = get_java_string(env, _rulename);
+  STAP_PROBE1(HelperSDT, method__bt__delete, rulename);
+}

java/HelperSDT.h

@@ -1,6 +1,22 @@
 package org.systemtap.byteman.helper;
+import java.io.StringWriter;
+import java.io.PrintWriter;
+import java.lang.Throwable;
+
 public class HelperSDT<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>
 {
+    public void STAP_BACKTRACE(String rulename){
+	Throwable e = new Throwable();
+	StringWriter sw = new StringWriter();
+	e.printStackTrace(new PrintWriter(sw));
+	String exceptionAsString = sw.toString();
+	String[] stackline = exceptionAsString.split("\n");
+	int __counter = 0;
+	for(String result : stackline){
+	    METHOD_STAP_BT(rulename, result, __counter);
+	    __counter++;
+	}
+    }
     public native void METHOD_STAP_PROBE0(String rulename);
     public native void METHOD_STAP_PROBE1(String rulename, T2 arg1);
     public native void METHOD_STAP_PROBE2(String rulename, T2 arg1, T3 arg2);
@@ -12,7 +28,9 @@ public class HelperSDT<T2, T3, T4, T5, T6, T7, T8, T9, T10, T11>
     public native void METHOD_STAP_PROBE8(String rulename, T2 arg1, T3 arg2, T4 arg3, T5 arg4, T6 arg5, T7 arg6, T8 arg7, T9 arg8);
     public native void METHOD_STAP_PROBE9(String rulename, T2 arg1, T3 arg2, T4 arg3, T5 arg4, T6 arg5, T7 arg6, T8 arg7, T9 arg8, T10 arg9);
     public native void METHOD_STAP_PROBE10(String rulename, T2 arg1, T3 arg2, T4 arg3, T5 arg4, T6 arg5, T7 arg6, T8 arg7, T9 arg8, T10 arg9, T11 arg10);
-    static{ 
-        System.loadLibrary("HelperSDT_" + System.getProperty("os.arch")); 
+    public native void METHOD_STAP_BT(String rulename, String exceptionAsString, int __counter);
+    public native void METHOD_BT_DELETE(String rulename);
+    static{
+        System.loadLibrary("HelperSDT_" + System.getProperty("os.arch"));
     }
 }

java/org/systemtap/byteman/helper/HelperSDT.java

@@ -7,11 +7,12 @@
 # $5 - method
 # $6 - number of args
 # $7 - entry/exit/line
+# $8 - backtrace trigger
 
 exec 1>&2  # redirect byteman/etc. tracing output to stderr, for easier filtering
 
-if [ $# -ne 7 ]; then
-    echo "need exactly seven arguments"
+if [[ $# -gt 8 || $# -lt 7 ]]; then
+    echo "need seven or eight arguments"
     exit 1
 fi
 
@@ -23,6 +24,12 @@ arg_method=$5
 arg_argcount=$6
 arg_probetype=$7
 
+if [ $# -eq 7 ]; then
+    arg_backtrace=0
+else
+    arg_backtrace=$8
+fi
+
 SYSTEMTAP_DIR=${SYSTEMTAP_DIR-$HOME/.systemtap}
 BYTEMAN_HOME=${BYTEMAN_HOME-/usr/share/java/byteman}
 JAVA_HOME=${JAVA_HOME-/usr/lib/jvm/java}
@@ -40,7 +47,7 @@ fi
 # the byteman and byteman-submit jars should be in ${BYTEMAN_HOME}/lib
 BYTEMAN_JAR=${BYTEMAN_HOME}/byteman.jar
 if [ ! -r ${BYTEMAN_JAR} ]; then
-    echo "Missing $BYTEMAN_JAR" 
+    echo "Missing $BYTEMAN_JAR"
     exit 1
 fi
 
@@ -95,7 +102,7 @@ mkdir -p $flagdir
 if [[ $arg_jvmpid != *[[:digit:]]* ]]; then
     target_pid=`jps -l | grep $arg_jvmpid | cut -f1 -d" "`
     for target in $target_pid; do
-	$0 $arg_command $target $arg_rulename $arg_class $arg_method $arg_argcount $arg_probetype
+	$0 $arg_command $target $arg_rulename $arg_class $arg_method $arg_argcount $arg_probetype $arg_backtrace
     done;
     exit 0
 else
@@ -119,6 +126,7 @@ if [ -s $byteman_installed_portfile ]; then
         echo "Byteman agent reused for java pid $target_pid, port $bmport"
     fi
 
+
     # XXX: liveness-check the port; bmsubmit with no argument just lists current rules
     # if fails, delete the _portfile and retry everything
 else
@@ -132,7 +140,7 @@ else
 
 # There are two ways to invoke and run byteman operations with the jvm's we're interested
 # in, we can alter the startup arguments to include a -javaagent parameter, or use
-# byteman and its use of VMAttach libraries, for our case it always makes sense to use 
+# byteman and its use of VMAttach libraries, for our case it always makes sense to use
 # byteman classes directly and avoid -javaagent
 
     if [ "$STAPBM_VERBOSE" != "no" ]; then
@@ -174,20 +182,31 @@ function echo_bytemanrule()
 	    ;;
     esac
     echo "IF TRUE"
+    if [ "$arg_backtrace" == "1" ]; then
+	echo 'DO STAP_BACKTRACE("'$arg_rulename'");'
+    else
+	echo -n 'DO '
+    fi
     case "$arg_argcount" in
-        0) echo 'DO METHOD_STAP_PROBE0("'$arg_rulename'")' ;;
-        1) echo 'DO METHOD_STAP_PROBE1("'$arg_rulename'", $1)' ;;
-        2) echo 'DO METHOD_STAP_PROBE2("'$arg_rulename'", $1, $2)' ;;
-        3) echo 'DO METHOD_STAP_PROBE3("'$arg_rulename'", $1, $2, $3)' ;;
-        4) echo 'DO METHOD_STAP_PROBE4("'$arg_rulename'", $1, $2, $3, $4)' ;;
-        5) echo 'DO METHOD_STAP_PROBE5("'$arg_rulename'", $1, $2, $3, $4, $5)' ;;
-        6) echo 'DO METHOD_STAP_PROBE6("'$arg_rulename'", $1, $2, $3, $4, $5, $6)' ;;
-        7) echo 'DO METHOD_STAP_PROBE7("'$arg_rulename'", $1, $2, $3, $4, $5, $6, $7)' ;;
-        8) echo 'DO METHOD_STAP_PROBE8("'$arg_rulename'", $1, $2, $3, $4, $5, $6, $7, $8)' ;;
-        9) echo 'DO METHOD_STAP_PROBE9("'$arg_rulename'", $1, $2, $3, $4, $5, $6, $7, $8, $9)' ;;
-	10) echo 'DO METHOD_STAP_PROBE10("'$arg_rulename'", $1, $2, $3, $4, $5, $6, $7, $8, $9, $10)' ;;
+        0) echo -n 'METHOD_STAP_PROBE0("'$arg_rulename'")' ;;
+        1) echo -n 'METHOD_STAP_PROBE1("'$arg_rulename'", $1)' ;;
+        2) echo -n 'METHOD_STAP_PROBE2("'$arg_rulename'", $1, $2)' ;;
+        3) echo -n 'METHOD_STAP_PROBE3("'$arg_rulename'", $1, $2, $3)' ;;
+        4) echo -n 'METHOD_STAP_PROBE4("'$arg_rulename'", $1, $2, $3, $4)' ;;
+        5) echo -n 'METHOD_STAP_PROBE5("'$arg_rulename'", $1, $2, $3, $4, $5)' ;;
+        6) echo -n 'METHOD_STAP_PROBE6("'$arg_rulename'", $1, $2, $3, $4, $5, $6)' ;;
+        7) echo -n 'METHOD_STAP_PROBE7("'$arg_rulename'", $1, $2, $3, $4, $5, $6, $7)' ;;
+        8) echo -n 'METHOD_STAP_PROBE8("'$arg_rulename'", $1, $2, $3, $4, $5, $6, $7, $8)' ;;
+        9) echo -n 'METHOD_STAP_PROBE9("'$arg_rulename'", $1, $2, $3, $4, $5, $6, $7, $8, $9)' ;;
+	10) echo -n 'METHOD_STAP_PROBE10("'$arg_rulename'", $1, $2, $3, $4, $5, $6, $7, $8, $9, $10)' ;;
         *) echo 'bad arg-count'; exit 1 ;;
     esac
+    if [ "$arg_backtrace" == "1" ]; then
+	echo ';'
+	echo 'METHOD_BT_DELETE("'$arg_rulename'")'
+    else
+	echo ''
+    fi
     echo "ENDRULE"
 }