From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed, 3 Nov 2021 16:14:09 +0000 (-0400)
Subject: Refactoring/fix: desc match enabler: handle error internally
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=8bff0fc3a53e182b6fdc8f70cedc564adc435afa;p=lttng-modules.git

Refactoring/fix: desc match enabler: handle error internally

This actually ensures that callers don't mistakenly consider a negative
return value (error) as a match success.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I27fe42b4d1d018b9f69de62a0cd8b43c77a61fa5
---

diff --git a/include/lttng/events-internal.h b/include/lttng/events-internal.h
index ee2a4ff2..5a1b9160 100644
--- a/include/lttng/events-internal.h
+++ b/include/lttng/events-internal.h
@@ -817,7 +817,7 @@ int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler_common
 		struct lttng_kernel_abi_filter_bytecode __user *bytecode);
 void lttng_event_enabler_destroy(struct lttng_event_enabler_common *event_enabler);
 
-int lttng_desc_match_enabler(const struct lttng_kernel_event_desc *desc,
+bool lttng_desc_match_enabler(const struct lttng_kernel_event_desc *desc,
 		struct lttng_event_enabler_common *enabler);
 bool lttng_event_enabler_match_event(struct lttng_event_enabler_common *event_enabler,
 		struct lttng_kernel_event_common *event);
diff --git a/src/lttng-events.c b/src/lttng-events.c
index c212ff3d..2abe3ead 100644
--- a/src/lttng-events.c
+++ b/src/lttng-events.c
@@ -1945,7 +1945,8 @@ int lttng_match_enabler_name(const char *desc_name,
 	return 1;
 }
 
-int lttng_desc_match_enabler(const struct lttng_kernel_event_desc *desc,
+static
+int lttng_desc_match_enabler_check(const struct lttng_kernel_event_desc *desc,
 		struct lttng_event_enabler_common *enabler)
 {
 	const char *desc_name, *enabler_name;
@@ -2034,6 +2035,19 @@ int lttng_desc_match_enabler(const struct lttng_kernel_event_desc *desc,
 	}
 }
 
+bool lttng_desc_match_enabler(const struct lttng_kernel_event_desc *desc,
+		struct lttng_event_enabler_common *enabler)
+{
+	int ret;
+
+	ret = lttng_desc_match_enabler_check(desc, enabler);
+	if (ret < 0) {
+		WARN_ON_ONCE(1);
+		return false;
+	}
+	return ret;
+}
+
 bool lttng_event_enabler_match_event(struct lttng_event_enabler_common *event_enabler,
 		struct lttng_kernel_event_common *event)
 {
diff --git a/src/lttng-syscalls.c b/src/lttng-syscalls.c
index 2c3b8af0..b5bd5bd3 100644
--- a/src/lttng-syscalls.c
+++ b/src/lttng-syscalls.c
@@ -554,8 +554,8 @@ int lttng_create_syscall_event_if_missing(const struct trace_syscall_entry *tabl
 			/* Unknown syscall */
 			continue;
 		}
-		if (lttng_desc_match_enabler(desc,
-				lttng_event_recorder_enabler_as_enabler(syscall_event_enabler)) <= 0)
+		if (!lttng_desc_match_enabler(desc,
+				lttng_event_recorder_enabler_as_enabler(syscall_event_enabler)))
 			continue;
 		/*
 		 * Check if already created.