tools lib traceevent: Get rid of die() in some string conversion functions

Those functions stringify filter arguments.

As caller of those functions handles NULL string properly, it seems that
it's enough to return NULL rather than calling die().

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/878uvkgx9f.fsf@sejong.aot.lge.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/traceevent/parse-filter.c

@@ -1361,8 +1361,10 @@ enum pevent_errno pevent_filter_add_filter_str(struct event_filter *filter,
 		if (ret >= 0 && pevent->test_filters) {
 			char *test;
 			test = pevent_filter_make_string(filter, event->event->id);
-			printf(" '%s: %s'\n", event->event->name, test);
-			free(test);
+			if (test) {
+				printf(" '%s: %s'\n", event->event->name, test);
+				free(test);
+			}
 		}
 	}
 
@@ -2050,7 +2052,6 @@ static char *op_to_str(struct event_filter *filter, struct filter_arg *arg)
 	int left_val = -1;
 	int right_val = -1;
 	int val;
-	int len;
 
 	switch (arg->op.type) {
 	case FILTER_OP_AND:
@@ -2097,11 +2098,7 @@ static char *op_to_str(struct event_filter *filter, struct filter_arg *arg)
 				default:
 					break;
 				}
-				str = malloc_or_die(6);
-				if (val)
-					strcpy(str, "TRUE");
-				else
-					strcpy(str, "FALSE");
+				asprintf(&str, val ? "TRUE" : "FALSE");
 				break;
 			}
 		}
@@ -2119,10 +2116,7 @@ static char *op_to_str(struct event_filter *filter, struct filter_arg *arg)
 			break;
 		}
 
-		len = strlen(left) + strlen(right) + strlen(op) + 10;
-		str = malloc_or_die(len);
-		snprintf(str, len, "(%s) %s (%s)",
-			 left, op, right);
+		asprintf(&str, "(%s) %s (%s)", left, op, right);
 		break;
 
 	case FILTER_OP_NOT:
@@ -2138,16 +2132,10 @@ static char *op_to_str(struct event_filter *filter, struct filter_arg *arg)
 			right_val = 0;
 		if (right_val >= 0) {
 			/* just return the opposite */
-			str = malloc_or_die(6);
-			if (right_val)
-				strcpy(str, "FALSE");
-			else
-				strcpy(str, "TRUE");
+			asprintf(&str, right_val ? "FALSE" : "TRUE");
 			break;
 		}
-		len = strlen(right) + strlen(op) + 3;
-		str = malloc_or_die(len);
-		snprintf(str, len, "%s(%s)", op, right);
+		asprintf(&str, "%s(%s)", op, right);
 		break;
 
 	default:
@@ -2161,11 +2149,9 @@ static char *op_to_str(struct event_filter *filter, struct filter_arg *arg)
 
 static char *val_to_str(struct event_filter *filter, struct filter_arg *arg)
 {
-	char *str;
-
-	str = malloc_or_die(30);
+	char *str = NULL;
 
-	snprintf(str, 30, "%lld", arg->value.val);
+	asprintf(&str, "%lld", arg->value.val);
 
 	return str;
 }
@@ -2181,7 +2167,6 @@ static char *exp_to_str(struct event_filter *filter, struct filter_arg *arg)
 	char *rstr;
 	char *op;
 	char *str = NULL;
-	int len;
 
 	lstr = arg_to_str(filter, arg->exp.left);
 	rstr = arg_to_str(filter, arg->exp.right);
@@ -2220,12 +2205,11 @@ static char *exp_to_str(struct event_filter *filter, struct filter_arg *arg)
 		op = "^";
 		break;
 	default:
-		die("oops in exp");
+		op = "[ERROR IN EXPRESSION TYPE]";
+		break;
 	}
 
-	len = strlen(op) + strlen(lstr) + strlen(rstr) + 4;
-	str = malloc_or_die(len);
-	snprintf(str, len, "%s %s %s", lstr, op, rstr);
+	asprintf(&str, "%s %s %s", lstr, op, rstr);
 out:
 	free(lstr);
 	free(rstr);
@@ -2239,7 +2223,6 @@ static char *num_to_str(struct event_filter *filter, struct filter_arg *arg)
 	char *rstr;
 	char *str = NULL;
 	char *op = NULL;
-	int len;
 
 	lstr = arg_to_str(filter, arg->num.left);
 	rstr = arg_to_str(filter, arg->num.right);
@@ -2270,10 +2253,7 @@ static char *num_to_str(struct event_filter *filter, struct filter_arg *arg)
 		if (!op)
 			op = "<=";
 
-		len = strlen(lstr) + strlen(op) + strlen(rstr) + 4;
-		str = malloc_or_die(len);
-		sprintf(str, "%s %s %s", lstr, op, rstr);
-
+		asprintf(&str, "%s %s %s", lstr, op, rstr);
 		break;
 
 	default:
@@ -2291,7 +2271,6 @@ static char *str_to_str(struct event_filter *filter, struct filter_arg *arg)
 {
 	char *str = NULL;
 	char *op = NULL;
-	int len;
 
 	switch (arg->str.type) {
 	case FILTER_CMP_MATCH:
@@ -2309,12 +2288,8 @@ static char *str_to_str(struct event_filter *filter, struct filter_arg *arg)
 		if (!op)
 			op = "!~";
 
-		len = strlen(arg->str.field->name) + strlen(op) +
-			strlen(arg->str.val) + 6;
-		str = malloc_or_die(len);
-		snprintf(str, len, "%s %s \"%s\"",
-			 arg->str.field->name,
-			 op, arg->str.val);
+		asprintf(&str, "%s %s \"%s\"",
+			 arg->str.field->name, op, arg->str.val);
 		break;
 
 	default:
@@ -2326,15 +2301,11 @@ static char *str_to_str(struct event_filter *filter, struct filter_arg *arg)
 
 static char *arg_to_str(struct event_filter *filter, struct filter_arg *arg)
 {
-	char *str;
+	char *str = NULL;
 
 	switch (arg->type) {
 	case FILTER_ARG_BOOLEAN:
-		str = malloc_or_die(6);
-		if (arg->boolean.value)
-			strcpy(str, "TRUE");
-		else
-			strcpy(str, "FALSE");
+		asprintf(&str, arg->boolean.value ? "TRUE" : "FALSE");
 		return str;
 
 	case FILTER_ARG_OP:
@@ -2369,7 +2340,7 @@ static char *arg_to_str(struct event_filter *filter, struct filter_arg *arg)
  *
  * Returns a string that displays the filter contents.
  *  This string must be freed with free(str).
- *  NULL is returned if no filter is found.
+ *  NULL is returned if no filter is found or allocation failed.
  */
 char *
 pevent_filter_make_string(struct event_filter *filter, int event_id)