Drop support for kernels < 3.0 from skb instrumentation

[lttng-modules.git] / lttng-context-hostname.c

diff --git a/lttng-context-hostname.c b/lttng-context-hostname.c
index 7cf7f7c849b6a9d9572257d76b1501c842a48aab..e485aa9742c567a2befb343ffa9e17e925af2f4f 100644 (file)
--- a/lttng-context-hostname.c
+++ b/lttng-context-hostname.c
@@ -1,33 +1,20 @@
-/*
+/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
+ *
  * lttng-context-hostname.c
  *
  * LTTng hostname context.
  *
  * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * This library 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; only
- * version 2.1 of the License.
- *
- * This library 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 this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/utsname.h>
-#include "lttng-events.h"
-#include "wrapper/ringbuffer/frontend_types.h"
-#include "wrapper/vmalloc.h"
-#include "lttng-tracer.h"
+#include <lttng-events.h>
+#include <wrapper/ringbuffer/frontend_types.h>
+#include <wrapper/vmalloc.h>
+#include <lttng-tracer.h>
 
 #define LTTNG_HOSTNAME_CTX_LEN (__NEW_UTS_LEN + 1)
 
@@ -65,6 +52,29 @@ void hostname_record(struct lttng_ctx_field *field,
        }
 }
 
+static
+void hostname_get_value(struct lttng_ctx_field *field,
+               struct lttng_probe_ctx *lttng_probe_ctx,
+               union lttng_ctx_value *value)
+{
+       struct nsproxy *nsproxy;
+       struct uts_namespace *ns;
+       char *hostname;
+
+       /*
+        * No need to take the RCU read-side lock to read current
+        * nsproxy. (documented in nsproxy.h)
+        */
+       nsproxy = current->nsproxy;
+       if (nsproxy) {
+               ns = nsproxy->uts_ns;
+               hostname = ns->name.nodename;
+       } else {
+               hostname = "";
+       }
+       value->str = hostname;
+}
+
 int lttng_add_hostname_to_ctx(struct lttng_ctx **ctx)
 {
        struct lttng_ctx_field *field;
@@ -89,11 +99,9 @@ int lttng_add_hostname_to_ctx(struct lttng_ctx **ctx)
 
        field->get_size = hostname_get_size;
        field->record = hostname_record;
+       field->get_value = hostname_get_value;
+       lttng_context_update(*ctx);
        wrapper_vmalloc_sync_all();
        return 0;
 }
 EXPORT_SYMBOL_GPL(lttng_add_hostname_to_ctx);
-
-MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("Linux Trace Toolkit Perf Support");