[12/17] libtracefs: Add error message when match or init fails from bad events

diff --git a/src/tracefs-sqlhist.c b/src/tracefs-sqlhist.c
index 0489657bea03..d39851845570 100644
--- a/src/tracefs-sqlhist.c
+++ b/src/tracefs-sqlhist.c
@@ -876,6 +876,101 @@  static int build_filter(struct tracefs_synth *synth,
 	return ret;
 }
 
+static int test_event_exists(struct tep_handle *tep, struct sqlhist_bison *sb,
+			     struct expr *expr, struct tep_event **pevent)
+{
+	const char *system = expr->field.system;
+	const char *event_name = expr->field.event;
+	struct tep_event *event;
+
+	event = tep_find_event_by_name(tep, system, event_name);
+	if (pevent)
+		*pevent = event;
+	if (event)
+		return 0;
+
+	sb->line_no = expr->line;
+	sb->line_idx = expr->idx;
+
+	parse_error(sb, expr->field.raw, "event not found\n");
+	return -1;
+}
+
+static int test_field_exists(struct tep_handle *tep, struct sqlhist_bison *sb,
+			     struct expr *expr)
+{
+	struct tep_event *event;
+
+	if (test_event_exists(tep, sb, expr, &event))
+		return -1;
+
+	if (trace_verify_event_field(event, expr->field.field, NULL))
+		return 0;
+
+	sb->line_no = expr->line;
+	sb->line_idx = expr->idx;
+
+	parse_error(sb, expr->field.raw, "Field '%s' not part of event %s\n",
+		    expr->field.field, expr->field.event);
+	return -1;
+}
+
+static void *field_match_error(struct tep_handle *tep, struct sqlhist_bison *sb,
+			       struct match *match)
+{
+	switch (errno) {
+	case ENODEV:
+	case EBADE:
+		break;
+	default:
+		/* System error */
+		return NULL;
+	}
+
+	/* ENODEV means that an event or field does not exist */
+	if (errno == ENODEV) {
+		if (test_field_exists(tep, sb, match->lval))
+			return NULL;
+		if (test_field_exists(tep, sb, match->rval))
+			return NULL;
+		return NULL;
+	}
+
+	/* fields exist, but values are not compatible */
+	sb->line_no = match->lval->line;
+	sb->line_idx = match->lval->idx;
+
+	parse_error(sb, match->lval->field.raw,
+		    "Field '%s' is not compatible to match field '%s'\n",
+		    match->lval->field.raw, match->rval->field.raw);
+	return NULL;
+}
+
+static void *synth_init_error(struct tep_handle *tep, struct sql_table *table)
+{
+	struct sqlhist_bison *sb = table->sb;
+	struct match *match = table->matches;
+
+	switch (errno) {
+	case ENODEV:
+	case EBADE:
+		break;
+	default:
+		/* System error */
+		return NULL;
+	}
+
+	/* ENODEV could mean that start or end events do not exist */
+	if (errno == ENODEV) {
+		if (test_event_exists(tep, sb, table->from, NULL))
+			return NULL;
+		if (test_event_exists(tep, sb, table->to, NULL))
+			return NULL;
+	}
+
+	return field_match_error(tep, sb, match);
+}
+
 static struct tracefs_synth *build_synth(struct tep_handle *tep,
 					 const char *name,
 					 struct sql_table *table)
@@ -926,7 +1021,7 @@  static struct tracefs_synth *build_synth(struct tep_handle *tep,
 				   start_event, end_system, end_event,
 				   start_match, end_match, NULL);
 	if (!synth)
-		return NULL;
+		return synth_init_error(tep, table);
 
 	for (match = match->next; match; match = match->next) {
 		ret = test_match(table, match);
@@ -939,8 +1034,10 @@  static struct tracefs_synth *build_synth(struct tep_handle *tep,
 		ret = tracefs_synth_add_match_field(synth,
 						    start_match,
 						    end_match, NULL);
-		if (ret < 0)
+		if (ret < 0) {
+			field_match_error(tep, table->sb, match);
 			goto free;
+		}
 	}
 
 	for (expr = table->selections; expr; expr = expr->next) {