From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Wed, 29 Jan 2020 04:39:01 +0000 (-0500)
Subject: directory-handle: query if instance is backed by a file descriptor
X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=commitdiff_plain;h=9a1a997f2f22b556f63437d911b98c7b522b38e4

directory-handle: query if instance is backed by a file descriptor

Allow a user of a directory handle to know if a given instance is
backed by a file descriptor. This is needed to ensure the fd-tracker
can accurately track the number of file descriptors in use at a given
moment.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I64aeeae2623a35ed07964432bb18b16aeeeb89ec
---

diff --git a/src/common/compat/directory-handle.c b/src/common/compat/directory-handle.c
index 9548da216..729f69cb9 100644
--- a/src/common/compat/directory-handle.c
+++ b/src/common/compat/directory-handle.c
@@ -248,6 +248,13 @@ int lttng_directory_handle_stat(const struct lttng_directory_handle *handle,
 	return fstatat(handle->dirfd, path, st, 0);
 }
 
+LTTNG_HIDDEN
+bool lttng_directory_handle_uses_fd(
+		const struct lttng_directory_handle *handle)
+{
+	return handle->dirfd != AT_FDCWD;
+}
+
 static
 int lttng_directory_handle_mkdir(
 		const struct lttng_directory_handle *handle,
@@ -617,6 +624,13 @@ end:
 	return ret;
 }
 
+LTTNG_HIDDEN
+bool lttng_directory_handle_uses_fd(
+		const struct lttng_directory_handle *handle)
+{
+	return false;
+}
+
 static
 int lttng_directory_handle_mkdir(const struct lttng_directory_handle *handle,
 		const char *subdirectory, mode_t mode)
diff --git a/src/common/compat/directory-handle.h b/src/common/compat/directory-handle.h
index 551fa50b4..b6ee8b384 100644
--- a/src/common/compat/directory-handle.h
+++ b/src/common/compat/directory-handle.h
@@ -267,6 +267,14 @@ int lttng_directory_handle_stat(
 		const char *name,
 		struct stat *stat_buf);
 
+/*
+ * Returns true if this directory handle is backed by a file
+ * descriptor, false otherwise.
+ */
+LTTNG_HIDDEN
+bool lttng_directory_handle_uses_fd(
+		const struct lttng_directory_handle *handle);
+
 /*
  * Compare two directory handles.
  *