[libvirt] [PATCHv2] rpc: Retrieve peer PID via new getsockopt() for Mac

[Doug Goldstein]

While LOCAL_PEERCRED on the BSDs does not return the pid information of
the peer, Mac OS X 10.8 added LOCAL_PEERPID to retrieve the pid so we
should use that when its available to get that information.
---
v2:
* Make LOCAL_PEERPID call non-fatal in case the user built the binary on
  a system that supports it but then runs it on a kernel that does not
  support it
---
 src/rpc/virnetsocket.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/rpc/virnetsocket.c b/src/rpc/virnetsocket.c
index e8cdfa6..7126c4f 100644
--- a/src/rpc/virnetsocket.c
+++ b/src/rpc/virnetsocket.c
@@ -1195,12 +1195,29 @@ int virNetSocketGetUNIXIdentity(virNetSocketPtr sock,
         return -1;
     }
 
-    /* PID and process creation time are not supported on BSDs */
+    /* PID and process creation time are not supported on BSDs by
+     * LOCAL_PEERCRED.
+     */
     *pid = -1;
     *timestamp = -1;
     *uid = cr.cr_uid;
     *gid = cr.cr_gid;
 
+# ifdef LOCAL_PEERPID
+    /* Exists on Mac OS X 10.8 for retrieving the peer's PID */
+    cr_len = sizeof(*pid);
+
+    if (getsockopt(sock->fd, VIR_SOL_PEERCRED, LOCAL_PEERPID, pid, &cr_len) < 0) {
+        virReportSystemError(errno, "%s",
+                             _("Failed to get client socket PID"));
+        /* Don't treat this as fatal, but do set the value to something sane
+         * in case the user built this on a system that has LOCAL_PEERPID
+         * defined but the kernel does not actually support it.
+         */
+        *pid = -1;
+    }
+# endif
+
     virObjectUnlock(sock);
     return 0;
 }
-- 
1.8.1.5