[libvirt] [PATCH 1/2]cgroup: introduce kernel version check function for cgroup

[Chen Hanxiao]

From: Chen Hanxiao <chenhanxiao at cn.fujitsu.com>

Some cgroup value range may change
in the further kernel.
Introduce kernel version check function for cgroup.
This will be helpful to determine the proper values.

Signed-off-by: Chen Hanxiao <chenhanxiao at cn.fujitsu.com>
---
 src/util/vircgroup.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
index e99caf5..498bc20 100644
--- a/src/util/vircgroup.c
+++ b/src/util/vircgroup.c
@@ -38,6 +38,7 @@
 #include <sys/types.h>
 #include <signal.h>
 #include <dirent.h>
+#include <sys/utsname.h>
 
 #define __VIR_CGROUP_ALLOW_INCLUDE_PRIV_H__
 #include "vircgrouppriv.h"
@@ -74,6 +75,37 @@ typedef enum {
                                        */
 } virCgroupFlags;
 
+static int virCgroupGetKernelVersion(unsigned long *kernelVersion)
+{
+    struct utsname ver;
+
+    uname(&ver);
+
+    if (virParseVersionString(ver.release, kernelVersion, true) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, _("Unknown release: %s"), ver.release);
+        return -1;
+    }
+
+    return 0;
+}
+
+static bool virCgroupVersionCheck(const char * dstVersion)
+{
+    unsigned long currentVersion;
+    unsigned long version;
+
+    if (virCgroupGetKernelVersion(&currentVersion) < 0) {
+        return -1;
+    }
+
+    if (virParseVersionString(dstVersion, &version, true) < 0) {
+        return -1;
+    }
+
+    return (((long long)currentVersion - (long long)version) >= 0) ? true : false;
+}
+
+
 
 #ifdef VIR_CGROUP_SUPPORTED
 bool
-- 
1.8.2.1