From a95532a8ea22ce9ccc385cff97aa0a08f86da72f Mon Sep 17 00:00:00 2001
From: Tom Hromatka <tom.hromatka@oracle.com>
Date: Wed, 15 Dec 2021 21:22:20 +0000
Subject: [PATCH] libcgroup.so: Add a function to get the library version

Add a function, cgroup_version(), that returns the current
version of the libcgroup library.

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
Reviewed-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
---
 configure.ac                            |  1 +
 include/libcgroup/.gitignore            |  1 +
 include/libcgroup/groups.h              | 10 ++++++++++
 include/libcgroup/{init.h => init.h.in} | 19 +++++++++++++++++++
 src/api.c                               | 11 +++++++++++
 src/libcgroup-internal.h                | 10 ----------
 src/libcgroup.map                       |  1 +
 7 files changed, 43 insertions(+), 10 deletions(-)
 create mode 100644 include/libcgroup/.gitignore
 rename include/libcgroup/{init.h => init.h.in} (80%)

diff --git a/configure.ac b/configure.ac
index 2e6b0a5a..b87ba2bd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -207,6 +207,7 @@ AC_CONFIG_FILES([Makefile
 	scripts/init.d/cgred
 	samples/Makefile
 	include/Makefile
+	include/libcgroup/init.h
 	doc/Makefile
 	doc/man/Makefile
 	dist/Makefile
diff --git a/include/libcgroup/.gitignore b/include/libcgroup/.gitignore
new file mode 100644
index 00000000..6d7255a8
--- /dev/null
+++ b/include/libcgroup/.gitignore
@@ -0,0 +1 @@
+init.h
diff --git a/include/libcgroup/groups.h b/include/libcgroup/groups.h
index 0960a7d3..c30cbb94 100644
--- a/include/libcgroup/groups.h
+++ b/include/libcgroup/groups.h
@@ -607,6 +607,16 @@ int cgroup_convert_cgroup(struct cgroup * const out_cgroup,
 			  const struct cgroup * const in_cgroup,
 			  enum cg_version_t in_version);
 
+/**
+ * Get the cgroup version of a controller.  Version is set to CGROUP_UNK
+ * if the version cannot be determined.
+ *
+ * @param controller The controller of interest
+ * @param version The version of the controller
+ */
+int cgroup_get_controller_version(const char * const controller,
+		enum cg_version_t * const version);
+
 /**
  * @}
  * @}
diff --git a/include/libcgroup/init.h b/include/libcgroup/init.h.in
similarity index 80%
rename from include/libcgroup/init.h
rename to include/libcgroup/init.h.in
index ea2dcc98..9c63e684 100644
--- a/include/libcgroup/init.h
+++ b/include/libcgroup/init.h.in
@@ -13,6 +13,25 @@
 extern "C" {
 #endif
 
+#define CGROUP_VER_MAJOR	@LIBRARY_VERSION_MAJOR@
+#define CGROUP_VER_MINOR	@LIBRARY_VERSION_MINOR@
+#define CGROUP_VER_RELEASE	@LIBRARY_VERSION_RELEASE@
+
+struct cgroup_library_version {
+	unsigned int major;
+	unsigned int minor;
+	unsigned int release;
+};
+
+/**
+ * Query the library version information
+ *
+ * This function returns a pointer to a populated cgroup_library_version
+ * struct.  The caller does not need to free the structure when finished.
+ *
+ */
+const struct cgroup_library_version *cgroup_version(void);
+
 /**
  * @defgroup group_init 1. Initialization
  * @{
diff --git a/src/api.c b/src/api.c
index 353f82fd..ae4761e5 100644
--- a/src/api.c
+++ b/src/api.c
@@ -50,6 +50,12 @@
 #include <linux/un.h>
 #include <grp.h>
 
+const struct cgroup_library_version library_version = {
+	.major = CGROUP_VER_MAJOR,
+	.minor = CGROUP_VER_MINOR,
+	.release = CGROUP_VER_RELEASE,
+};
+
 /*
  * The errno which happend the last time (have to be thread specific)
  */
@@ -5777,3 +5783,8 @@ int cgroup_get_controller_version(const char * const controller,
 
 	return ECGROUPNOTEXIST;
 }
+
+const struct cgroup_library_version *cgroup_version(void)
+{
+	return &library_version;
+}
diff --git a/src/libcgroup-internal.h b/src/libcgroup-internal.h
index 16a92658..e704adae 100644
--- a/src/libcgroup-internal.h
+++ b/src/libcgroup-internal.h
@@ -308,16 +308,6 @@ extern void cgroup_dictionary_iterator_end(void **handle);
  */
 int cg_chmod_path(const char *path, mode_t mode, int owner_is_umask);
 
-/**
- * Get the cgroup version of a controller.  Version is set to CGROUP_UNK
- * if the version cannot be determined.
- *
- * @param controller The controller of interest
- * @param version The version of the controller
- */
-int cgroup_get_controller_version(const char * const controller,
-		enum cg_version_t * const version);
-
 /**
  * Build the path to the tasks or cgroup.procs file
  *
diff --git a/src/libcgroup.map b/src/libcgroup.map
index 3ce7e1b0..99788ac5 100644
--- a/src/libcgroup.map
+++ b/src/libcgroup.map
@@ -144,4 +144,5 @@ CGROUP_3.0 {
 	cgroup_convert_cgroup;
 	cgroup_cgxget;
 	cgroup_cgxset;
+	cgroup_version;
 } CGROUP_2.0;
-- 
2.47.2