[libvirt PATCH 1/3] vircgroup: introduce virCgroupGetInode function

[Pavel Hrdina <phrdina@xxxxxxxxxx>]

For new feature Fibre Channel VMID we will need to get inode of the
VM root cgroup as it is used in the new kernel API together with VMID.

Signed-off-by: Pavel Hrdina <phrdina@xxxxxxxxxx>
---
 src/libvirt_private.syms |  1 +
 src/util/vircgroup.c     | 37 +++++++++++++++++++++++++++++++++++++
 src/util/vircgroup.h     |  2 ++
 3 files changed, 40 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 6961cdb137..d8451fcfff 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1920,6 +1920,7 @@ virCgroupGetCpuShares;
 virCgroupGetDevicePermsString;
 virCgroupGetDomainTotalCpuStats;
 virCgroupGetFreezerState;
+virCgroupGetInode;
 virCgroupGetMemoryHardLimit;
 virCgroupGetMemorySoftLimit;
 virCgroupGetMemoryStat;
diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
index 1b3b28342e..ea702e7b63 100644
--- a/src/util/vircgroup.c
+++ b/src/util/vircgroup.c
@@ -3973,3 +3973,40 @@ virCgroupGetCpuPeriodQuota(virCgroup *cgroup, unsigned long long *period,
 
     return 0;
 }
+
+
+/**
+ * virCgroupGetInode:
+ *
+ * @cgroup: the cgroup to get inode for
+ *
+ * Get the @cgroup inode and return its value to the caller.
+ *
+ * Returns inode on success, -1 on error with error message reported.
+ */
+int
+virCgroupGetInode(virCgroup *cgroup)
+{
+    VIR_AUTOCLOSE fd = 0;
+    struct stat st;
+    int controller = virCgroupGetAnyController(cgroup);
+    g_autofree char *path = NULL;
+
+    if (controller < 0)
+        return -1;
+
+    if (virCgroupPathOfController(cgroup, controller, "", &path) < 0)
+        return -1;
+
+    if ((fd = open(path, O_RDONLY | O_NONBLOCK)) < 0) {
+        virReportSystemError(errno, _("failed to open cgroup '%s'"), path);
+        return -1;
+    }
+
+    if (fstat(fd, &st) < 0) {
+        virReportSystemError(errno, _("failed to get fstat for '%s'"), path);
+        return -1;
+    }
+
+    return st.st_ino;
+}
diff --git a/src/util/vircgroup.h b/src/util/vircgroup.h
index 8002cac570..690f09465c 100644
--- a/src/util/vircgroup.h
+++ b/src/util/vircgroup.h
@@ -283,3 +283,5 @@ int virCgroupSetOwner(virCgroup *cgroup,
 int virCgroupHasEmptyTasks(virCgroup *cgroup, int controller);
 
 bool virCgroupControllerAvailable(int controller);
+
+int virCgroupGetInode(virCgroup *cgroup);
-- 
2.31.1