Fix: cache the result of getpid() internally

[lttng-ust.git] / liblttng-ust / lttng-context-vpid.c

diff --git a/liblttng-ust/lttng-context-vpid.c b/liblttng-ust/lttng-context-vpid.c
index db76747a6445c9beb8cbd07ba0940b79fbb60e24..53fb314b8c0da1bdf353f00c59c953879b4ed150 100644 (file)
--- a/liblttng-ust/lttng-context-vpid.c
+++ b/liblttng-ust/lttng-context-vpid.c
@@ -1,29 +1,32 @@
 /*
- * (C) Copyright       2009-2011 -
- *             Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * lttng-context-vpid.c
  *
  * LTTng UST vpid 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
  */
 
+#define _LGPL_SOURCE
 #include <sys/types.h>
 #include <unistd.h>
 #include <lttng/ust-events.h>
 #include <lttng/ust-tracer.h>
 #include <lttng/ringbuffer-config.h>
 
-#ifdef __linux__
-static inline
-pid_t wrapper_getpid(void)
-{
-       return getpid();
-}
-
-void lttng_context_vpid_reset(void)
-{
-}
-#else
 /*
  * We cache the result to ensure we don't trigger a system call for
  * each event.
@@ -46,10 +49,9 @@ void lttng_context_vpid_reset(void)
 {
        cached_vpid = 0;
 }
-#endif
 
 static
-size_t vpid_get_size(size_t offset)
+size_t vpid_get_size(struct lttng_ctx_field *field, size_t offset)
 {
        size_t size = 0;
 
@@ -61,7 +63,7 @@ size_t vpid_get_size(size_t offset)
 static
 void vpid_record(struct lttng_ctx_field *field,
                 struct lttng_ust_lib_ring_buffer_ctx *ctx,
-                struct ltt_channel *chan)
+                struct lttng_channel *chan)
 {
        pid_t pid;
 
@@ -70,6 +72,16 @@ void vpid_record(struct lttng_ctx_field *field,
        chan->ops->event_write(ctx, &pid, sizeof(pid));
 }
 
+static
+void vpid_get_value(struct lttng_ctx_field *field,
+               struct lttng_ctx_value *value)
+{
+       pid_t pid;
+
+       pid = wrapper_getpid();
+       value->u.s64 = pid;
+}
+
 int lttng_add_vpid_to_ctx(struct lttng_ctx **ctx)
 {
        struct lttng_ctx_field *field;
@@ -91,5 +103,7 @@ int lttng_add_vpid_to_ctx(struct lttng_ctx **ctx)
        field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
        field->get_size = vpid_get_size;
        field->record = vpid_record;
+       field->get_value = vpid_get_value;
+       lttng_context_update(*ctx);
        return 0;
 }