parse-events: Handle opcode parsing error

If an invalid opcode is encountered in parsing event print format, the
trace-cmd calls exit() without parsing any other events.

This patch adds handling for such an error where the get_op_prio() is
called. If the return value is -1, then the event print format parsing
is skipped and parsing continues.

Cc: Michael Rubin <mrubin@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Link: http://lkml.kernel.org/r/1311619257-4970-1-git-send-email-vnagarnaik@google.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

tools/lib/traceevent/event-parse.c

@@ -1592,7 +1592,7 @@ static int get_op_prio(char *op)
 		case '?':
 			return 16;
 		default:
-			die("unknown op '%c'", op[0]);
+			do_warning("unknown op '%c'", op[0]);
 			return -1;
 		}
 	} else {
@@ -1613,22 +1613,22 @@ static int get_op_prio(char *op)
 		} else if (strcmp(op, "||") == 0) {
 			return 15;
 		} else {
-			die("unknown op '%s'", op);
+			do_warning("unknown op '%s'", op);
 			return -1;
 		}
 	}
 }
 
-static void set_op_prio(struct print_arg *arg)
+static int set_op_prio(struct print_arg *arg)
 {
 
 	/* single ops are the greatest */
-	if (!arg->op.left || arg->op.left->type == PRINT_NULL) {
+	if (!arg->op.left || arg->op.left->type == PRINT_NULL)
 		arg->op.prio = 0;
-		return;
-	}
+	else
+		arg->op.prio = get_op_prio(arg->op.op);
 
-	arg->op.prio = get_op_prio(arg->op.op);
+	return arg->op.prio;
 }
 
 /* Note, *tok does not get freed, but will most likely be saved */
@@ -1710,7 +1710,10 @@ process_op(struct event_format *event, struct print_arg *arg, char **tok)
 		arg->op.op = token;
 		arg->op.left = left;
 
-		set_op_prio(arg);
+		if (set_op_prio(arg) == -1) {
+			event->flags |= EVENT_FL_FAILED;
+			goto out_free;
+		}
 
 		type = read_token_item(&token);
 		*tok = token;