[libvirt] [PATCH 04/13] Add API for checking if a cgroup is valid for a domain

[Daniel P. Berrange]

From: "Daniel P. Berrange" <berrange at redhat.com>

Add virCgroupIsValidMachine API to check whether a auto
detected cgroup is valid for a machine. This lets us
check if a VM has just been placed into some generic
shared cgroup, or worse, the root cgroup

Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
---
 src/libvirt_private.syms |  1 +
 src/util/vircgroup.c     | 42 ++++++++++++++++++++++++++++++++++++++++++
 src/util/vircgroup.h     |  5 +++++
 3 files changed, 48 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 49b9f9d..3be604b 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1182,6 +1182,7 @@ virCgroupGetMemSwapHardLimit;
 virCgroupGetMemSwapUsage;
 virCgroupHasController;
 virCgroupIsolateMount;
+virCgroupIsValidMachineGroup;
 virCgroupKill;
 virCgroupKillPainfully;
 virCgroupKillRecursive;
diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
index 94d19e0..1043318 100644
--- a/src/util/vircgroup.c
+++ b/src/util/vircgroup.c
@@ -67,6 +67,8 @@ typedef enum {
                                        */
 } virCgroupFlags;
 
+static int virCgroupPartitionEscape(char **path);
+
 bool virCgroupAvailable(void)
 {
     FILE *mounts = NULL;
@@ -91,6 +93,46 @@ bool virCgroupAvailable(void)
     return ret;
 }
 
+bool virCgroupIsValidMachineGroup(virCgroupPtr group,
+                                  const char *name,
+                                  const char *drivername)
+{
+    size_t i;
+    bool valid = false;
+    char *partname;
+
+    if (virAsprintf(&partname, "%s.libvirt-%s",
+                    name, drivername) < 0)
+        goto cleanup;
+
+    if (virCgroupPartitionEscape(&partname) < 0)
+        goto cleanup;
+    
+    for (i = 0; i < VIR_CGROUP_CONTROLLER_LAST; i++) {
+        char *tmp;
+
+        if (!group->controllers[i].placement)
+            continue;
+
+        tmp = strrchr(group->controllers[i].placement, '/');
+        if (!tmp)
+            goto cleanup;
+        tmp++;
+
+        if (STRNEQ(tmp, name) &&
+            STRNEQ(tmp, partname))
+            goto cleanup;
+
+    }
+    
+    valid = true;
+
+ cleanup:
+    VIR_FREE(partname);
+    return valid;
+}
+
+
 /**
  * virCgroupFree:
  *
diff --git a/src/util/vircgroup.h b/src/util/vircgroup.h
index 602d4ff..9bf0d7e 100644
--- a/src/util/vircgroup.h
+++ b/src/util/vircgroup.h
@@ -48,6 +48,11 @@ VIR_ENUM_DECL(virCgroupController);
 
 bool virCgroupAvailable(void);
 
+bool virCgroupIsValidMachineGroup(virCgroupPtr group,
+                                  const char *machinename,
+                                  const char *drivername);
+
+
 int virCgroupNewPartition(const char *path,
                           bool create,
                           int controllers,
-- 
1.8.1.4