X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-context-procname.c;h=4d41593e17cb503286e1355cbc3f03c0166b4c81;hb=8ca68914bea06267bce3cacdec8c821a7821e1a9;hp=d165be88277daada8bbb616c2db60572050f9aa2;hpb=9501d22f55b3a23f382f631c99b2325d1419b5da;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-context-procname.c b/liblttng-ust/lttng-context-procname.c
index d165be88..4d41593e 100644
--- a/liblttng-ust/lttng-context-procname.c
+++ b/liblttng-ust/lttng-context-procname.c
@@ -3,7 +3,7 @@
  *
  * LTTng UST procname context.
  *
- * Copyright (C) 2009-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * 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
@@ -23,6 +23,7 @@
 #include <lttng/ust-events.h>
 #include <lttng/ust-tracer.h>
 #include <lttng/ringbuffer-config.h>
+#include <urcu/tls-compat.h>
 #include <assert.h>
 #include "compat.h"
 
@@ -31,22 +32,26 @@
  * each event.
  * Upon exec, procname changes, but exec takes care of throwing away
  * this cached version.
+ * The procname can also change by calling prctl(). The procname should
+ * be set for a thread before the first event is logged within this
+ * thread.
  */
-static char cached_procname[17];
+typedef char procname_array[17];
+static DEFINE_URCU_TLS(procname_array, cached_procname);
 
 static inline
 char *wrapper_getprocname(void)
 {
-	if (caa_unlikely(!cached_procname[0])) {
-		lttng_ust_getprocname(cached_procname);
-		cached_procname[LTTNG_UST_PROCNAME_LEN - 1] = '\0';
+	if (caa_unlikely(!URCU_TLS(cached_procname)[0])) {
+		lttng_ust_getprocname(URCU_TLS(cached_procname));
+		URCU_TLS(cached_procname)[LTTNG_UST_PROCNAME_LEN - 1] = '\0';
 	}
-	return cached_procname;
+	return URCU_TLS(cached_procname);
 }
 
 void lttng_context_procname_reset(void)
 {
-	cached_procname[0] = '\0';
+	URCU_TLS(cached_procname)[0] = '\0';
 }
 
 static
@@ -61,7 +66,7 @@ size_t procname_get_size(size_t offset)
 static
 void procname_record(struct lttng_ctx_field *field,
 		 struct lttng_ust_lib_ring_buffer_ctx *ctx,
-		 struct ltt_channel *chan)
+		 struct lttng_channel *chan)
 {
 	char *procname;
 
@@ -69,6 +74,16 @@ void procname_record(struct lttng_ctx_field *field,
 	chan->ops->event_write(ctx, procname, LTTNG_UST_PROCNAME_LEN);
 }
 
+static
+void procname_get_value(struct lttng_ctx_field *field,
+		union lttng_ctx_value *value)
+{
+	char *procname;
+
+	procname = wrapper_getprocname();
+	value->str = procname;
+}
+
 int lttng_add_procname_to_ctx(struct lttng_ctx **ctx)
 {
 	struct lttng_ctx_field *field;
@@ -92,5 +107,15 @@ int lttng_add_procname_to_ctx(struct lttng_ctx **ctx)
 	field->event_field.type.u.array.length = LTTNG_UST_PROCNAME_LEN;
 	field->get_size = procname_get_size;
 	field->record = procname_record;
+	field->get_value = procname_get_value;
+	lttng_context_update(*ctx);
 	return 0;
 }
+
+/*
+ * Force a read (imply TLS fixup for dlopen) of TLS variables.
+ */
+void lttng_fixup_procname_tls(void)
+{
+	asm volatile ("" : : "m" (URCU_TLS(cached_procname)[0]));
+}