From: Simon McVittie <simon.mcvittie@collabora.co.uk>
Date: Wed, 18 Sep 2013 16:51:53 +0000 (+0100)
Subject: If sendmsg() with SCM_CREDS fails with EINVAL, retry with send()
X-Git-Tag: dbus-1.7.10~12
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3ca8a53e336a1a829bae93c70fe617af6493201a;p=thirdparty%2Fdbus.git

If sendmsg() with SCM_CREDS fails with EINVAL, retry with send()

Perhaps some OSs accept and ignore attempts to send a SCM_CREDS
message on a non-Unix socket, but GNU/kFreeBSD doesn't (and presumably
FreeBSD doesn't either).

Based on a patch by Svante Signell.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=69492
Tested-by: Svante Signell
Reviewed-by: Chengwei Yang <chengwei.yang@intel.com>
---

diff --git a/dbus/dbus-sysdeps-unix.c b/dbus/dbus-sysdeps-unix.c
index 19f5ea30a..c12f294e2 100644
--- a/dbus/dbus-sysdeps-unix.c
+++ b/dbus/dbus-sysdeps-unix.c
@@ -1572,13 +1572,19 @@ write_credentials_byte (int             server_fd,
                            |MSG_NOSIGNAL
 #endif
                            );
-#else
-  bytes_written = send (server_fd, buf, 1, 0
-#if HAVE_DECL_MSG_NOSIGNAL
-                        |MSG_NOSIGNAL
+
+  /* If we HAVE_CMSGCRED, the OS still might not let us sendmsg()
+   * with a SOL_SOCKET/SCM_CREDS message - for instance, FreeBSD
+   * only allows that on AF_UNIX. Try just doing a send() instead. */
+  if (bytes_written < 0 && errno == EINVAL)
 #endif
-                        );
+    {
+      bytes_written = send (server_fd, buf, 1, 0
+#if HAVE_DECL_MSG_NOSIGNAL
+                            |MSG_NOSIGNAL
 #endif
+                            );
+    }
 
   if (bytes_written < 0 && errno == EINTR)
     goto again;