security_util: Introduce virSecurityMoveRememberedLabel

A simple helper function that would be used from DAC and SELinux
drivers.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

src/security/security_util.c

@@ -256,3 +256,66 @@ virSecuritySetRememberedLabel(const char *name,
     VIR_FREE(ref_name);
     return ret;
 }
+
+
+int
+virSecurityMoveRememberedLabel(const char *name,
+                               const char *src,
+                               const char *dst)
+{
+    VIR_AUTOFREE(char *) ref_name = NULL;
+    VIR_AUTOFREE(char *) ref_value = NULL;
+    VIR_AUTOFREE(char *) attr_name = NULL;
+    VIR_AUTOFREE(char *) attr_value = NULL;
+
+    if (!(ref_name = virSecurityGetRefCountAttrName(name)) |
+        !(attr_name = virSecurityGetAttrName(name)))
+        return -1;
+
+    if (virFileGetXAttrQuiet(src, ref_name, &ref_value) < 0) {
+        if (errno == ENOSYS || errno == ENOTSUP) {
+            return -2;
+        } else if (errno != ENODATA) {
+            virReportSystemError(errno,
+                                 _("Unable to get XATTR %s on %s"),
+                                 ref_name, src);
+            return -1;
+        }
+    }
+
+    if (virFileGetXAttrQuiet(src, attr_name, &attr_value) < 0) {
+        if (errno == ENOSYS || errno == ENOTSUP) {
+            return -2;
+        } else if (errno != ENODATA) {
+            virReportSystemError(errno,
+                                 _("Unable to get XATTR %s on %s"),
+                                 attr_name, src);
+            return -1;
+        }
+    }
+
+    if (ref_value &&
+        virFileRemoveXAttr(src, ref_name) < 0) {
+        return -1;
+    }
+
+    if (attr_value &&
+        virFileRemoveXAttr(src, attr_name) < 0) {
+        return -1;
+    }
+
+    if (dst) {
+        if (ref_value &&
+            virFileSetXAttr(dst, ref_name, ref_value) < 0) {
+            return -1;
+        }
+
+        if (attr_value &&
+            virFileSetXAttr(dst, attr_name, attr_value) < 0) {
+            ignore_value(virFileRemoveXAttr(dst, ref_name));
+            return -1;
+        }
+    }
+
+    return 0;
+}

src/security/security_util.h

@@ -27,3 +27,8 @@ int
 virSecuritySetRememberedLabel(const char *name,
                               const char *path,
                               const char *label);
+
+int
+virSecurityMoveRememberedLabel(const char *name,
+                               const char *src,
+                               const char *dst);