audit: turn the audit fd into a static variable

As audit is pretty much just a special kind of logging we should treat
it similar, and manage the audit fd in a static variable.

This simplifies the audit fd sharing with the SELinux access checking
code quite a bit.

1 files changed, 71 insertions, 0 deletions

diff --git a/src/core/audit-fd.c b/src/core/audit-fd.c
new file mode 100644
index 0000000000..0a8626fbc2
--- /dev/null
+++ b/src/core/audit-fd.c
@@ -0,0 +1,71 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2012 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdbool.h>
+#include <errno.h>
+
+#include "audit-fd.h"
+#include "log.h"
+
+#ifdef HAVE_AUDIT
+
+#include <libaudit.h>
+
+static bool initialized = false;
+static int audit_fd;
+
+int get_audit_fd(void) {
+
+        if (!initialized) {
+                audit_fd = audit_open();
+
+                if (audit_fd < 0) {
+                        if (errno != EAFNOSUPPORT && errno != EPROTONOSUPPORT)
+                                log_error("Failed to connect to audit log: %m");
+
+                        audit_fd = errno ? -errno : -EINVAL;
+                }
+
+                initialized = true;
+        }
+
+        return audit_fd;
+}
+
+void close_audit_fd(void) {
+
+        if (initialized && audit_fd >= 0)
+                close_nointr_nofail(audit_fd);
+
+        initialized = true;
+        audit_fd = -ECONNRESET;
+}
+
+#else
+
+int get_audit_fd(void) {
+        return -EAFNOSUPPORT;
+}
+
+void close_audit_fd(void) {
+}
+
+#endif