X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=lttng-context-vppid.c;h=c18c553148d6e41a0339b9f77faf0dbe0fd5c6f9;hb=refs%2Fheads%2Fstable-2.5;hp=d55e12db6b2541afd1d7da7274fdb6385f326088;hpb=09fec6b43d11b3e0ece36f9e9e44b9627c1b565d;p=lttng-modules.git

diff --git a/lttng-context-vppid.c b/lttng-context-vppid.c
index d55e12db..c18c5531 100644
--- a/lttng-context-vppid.c
+++ b/lttng-context-vppid.c
@@ -1,27 +1,40 @@
 /*
- * (C) Copyright	2009-2011 -
- * 		Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * lttng-context-vppid.c
  *
  * LTTng vPPID context.
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * 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/syscalls.h>
-#include "ltt-events.h"
+#include "lttng-events.h"
 #include "wrapper/ringbuffer/frontend_types.h"
 #include "wrapper/vmalloc.h"
-#include "ltt-tracer.h"
+#include "lttng-tracer.h"
 
 static
 size_t vppid_get_size(size_t offset)
 {
 	size_t size = 0;
 
-	size += lib_ring_buffer_align(offset, ltt_alignof(pid_t));
+	size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
 	size += sizeof(pid_t);
 	return size;
 }
@@ -29,14 +42,32 @@ size_t vppid_get_size(size_t offset)
 static
 void vppid_record(struct lttng_ctx_field *field,
 		  struct lib_ring_buffer_ctx *ctx,
-		  struct ltt_channel *chan)
+		  struct lttng_channel *chan)
 {
+	struct task_struct *parent;
 	pid_t vppid;
 
+	/*
+	 * current nsproxy can be NULL when scheduled out of exit. pid_vnr uses
+	 * the current thread nsproxy to perform the lookup.
+	 */
+
+	/*
+	 * TODO: when we eventually add RCU subsystem instrumentation,
+	 * taking the rcu read lock here will trigger RCU tracing
+	 * recursively. We should modify the kernel synchronization so
+	 * it synchronizes both for RCU and RCU sched, and rely on
+	 * rcu_read_lock_sched_notrace.
+	 */
+
 	rcu_read_lock();
-	vppid = task_tgid_vnr(current->real_parent);
+	parent = rcu_dereference(current->real_parent);
+	if (!current->nsproxy)
+		vppid = 0;
+	else
+		vppid = task_tgid_vnr(parent);
 	rcu_read_unlock();
-	lib_ring_buffer_align_ctx(ctx, ltt_alignof(vppid));
+	lib_ring_buffer_align_ctx(ctx, lttng_alignof(vppid));
 	chan->ops->event_write(ctx, &vppid, sizeof(vppid));
 }
 
@@ -47,16 +78,21 @@ int lttng_add_vppid_to_ctx(struct lttng_ctx **ctx)
 	field = lttng_append_context(ctx);
 	if (!field)
 		return -ENOMEM;
+	if (lttng_find_context(*ctx, "vppid")) {
+		lttng_remove_context_field(ctx, field);
+		return -EEXIST;
+	}
 	field->event_field.name = "vppid";
 	field->event_field.type.atype = atype_integer;
 	field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
-	field->event_field.type.u.basic.integer.alignment = ltt_alignof(pid_t) * CHAR_BIT;
-	field->event_field.type.u.basic.integer.signedness = is_signed_type(pid_t);
+	field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
+	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
 	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
 	field->event_field.type.u.basic.integer.base = 10;
 	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
 	field->get_size = vppid_get_size;
 	field->record = vppid_record;
+	lttng_context_update(*ctx);
 	wrapper_vmalloc_sync_all();
 	return 0;
 }
@@ -65,3 +101,7 @@ EXPORT_SYMBOL_GPL(lttng_add_vppid_to_ctx);
 MODULE_LICENSE("GPL and additional rights");
 MODULE_AUTHOR("Mathieu Desnoyers");
 MODULE_DESCRIPTION("Linux Trace Toolkit vPPID Context");
+MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
+	__stringify(LTTNG_MODULES_MINOR_VERSION) "."
+	__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
+	LTTNG_MODULES_EXTRAVERSION);