Ensure system identity includes process start time

The polkit access driver will want to use the process start
time field. This was already set for network identities, but
not for the system identity.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
(cherry picked from commit e65667c0)

src/util/viridentity.c

@@ -35,6 +35,7 @@
 #include "virthread.h"
 #include "virutil.h"
 #include "virstring.h"
+#include "virprocess.h"
 
 #define VIR_FROM_THIS VIR_FROM_IDENTITY
 
@@ -142,11 +143,20 @@ virIdentityPtr virIdentityGetSystem(void)
     security_context_t con;
 #endif
     char *processid = NULL;
+    unsigned long long timestamp;
+    char *processtime = NULL;
 
     if (virAsprintf(&processid, "%llu",
                     (unsigned long long)getpid()) < 0)
         goto cleanup;
 
+    if (virProcessGetStartTime(getpid(), &timestamp) < 0)
+        goto cleanup;
+
+    if (timestamp != 0 &&
+        virAsprintf(&processtime, "%llu", timestamp) < 0)
+        goto cleanup;
+
     if (!(username = virGetUserName(getuid())))
         goto cleanup;
     if (virAsprintf(&userid, "%d", (int)getuid()) < 0)
@@ -198,6 +208,11 @@ virIdentityPtr virIdentityGetSystem(void)
                            VIR_IDENTITY_ATTR_UNIX_PROCESS_ID,
                            processid) < 0)
         goto error;
+    if (processtime &&
+        virIdentitySetAttr(ret,
+                           VIR_IDENTITY_ATTR_UNIX_PROCESS_TIME,
+                           processtime) < 0)
+        goto error;
 
 cleanup:
     VIR_FREE(username);
@@ -206,6 +221,7 @@ cleanup:
     VIR_FREE(groupid);
     VIR_FREE(seccontext);
     VIR_FREE(processid);
+    VIR_FREE(processtime);
     return ret;
 
 error: