* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
+#define _LGPL_SOURCE
+#include <stddef.h>
#include <lttng/ust-events.h>
#include <lttng/ust-tracer.h>
#include <lttng/ringbuffer-config.h>
#include <assert.h>
#include "compat.h"
+/* Maximum number of nesting levels for the procname cache. */
+#define PROCNAME_NESTING_MAX 2
+
/*
* We cache the result to ensure we don't trigger a system call for
* each event.
* be set for a thread before the first event is logged within this
* thread.
*/
-typedef char procname_array[17];
+typedef char procname_array[PROCNAME_NESTING_MAX][17];
+
static DEFINE_URCU_TLS(procname_array, cached_procname);
+static DEFINE_URCU_TLS(int, procname_nesting);
+
static inline
char *wrapper_getprocname(void)
{
- 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';
+ int nesting = CMM_LOAD_SHARED(URCU_TLS(procname_nesting));
+
+ if (caa_unlikely(nesting >= PROCNAME_NESTING_MAX))
+ return "<unknown>";
+ if (caa_unlikely(!URCU_TLS(cached_procname)[nesting][0])) {
+ CMM_STORE_SHARED(URCU_TLS(procname_nesting), nesting + 1);
+ /* Increment nesting before updating cache. */
+ cmm_barrier();
+ lttng_pthread_getname_np(URCU_TLS(cached_procname)[nesting], LTTNG_UST_ABI_PROCNAME_LEN);
+ URCU_TLS(cached_procname)[nesting][LTTNG_UST_ABI_PROCNAME_LEN - 1] = '\0';
+ /* Decrement nesting after updating cache. */
+ cmm_barrier();
+ CMM_STORE_SHARED(URCU_TLS(procname_nesting), nesting);
}
- return URCU_TLS(cached_procname);
+ return URCU_TLS(cached_procname)[nesting];
}
+/* Reset should not be called from a signal handler. */
void lttng_context_procname_reset(void)
{
- URCU_TLS(cached_procname)[0] = '\0';
+ CMM_STORE_SHARED(URCU_TLS(cached_procname)[1][0], '\0');
+ CMM_STORE_SHARED(URCU_TLS(procname_nesting), 1);
+ CMM_STORE_SHARED(URCU_TLS(cached_procname)[0][0], '\0');
+ CMM_STORE_SHARED(URCU_TLS(procname_nesting), 0);
}
static
-size_t procname_get_size(size_t offset)
+size_t procname_get_size(struct lttng_ctx_field *field, size_t offset)
{
- size_t size = 0;
-
- size += LTTNG_UST_PROCNAME_LEN;
- return size;
+ return LTTNG_UST_ABI_PROCNAME_LEN;
}
static
char *procname;
procname = wrapper_getprocname();
- chan->ops->event_write(ctx, procname, LTTNG_UST_PROCNAME_LEN);
+ chan->ops->event_write(ctx, procname, LTTNG_UST_ABI_PROCNAME_LEN);
}
static
void procname_get_value(struct lttng_ctx_field *field,
- union lttng_ctx_value *value)
+ struct lttng_ctx_value *value)
{
- char *procname;
-
- procname = wrapper_getprocname();
- value->str = procname;
+ value->u.str = wrapper_getprocname();
}
+static const struct lttng_type procname_array_elem_type =
+ __type_integer(char, BYTE_ORDER, 10, UTF8);
+
int lttng_add_procname_to_ctx(struct lttng_ctx **ctx)
{
struct lttng_ctx_field *field;
return -EEXIST;
}
field->event_field.name = "procname";
- field->event_field.type.atype = atype_array;
- field->event_field.type.u.array.elem_type.atype = atype_integer;
- field->event_field.type.u.array.elem_type.u.basic.integer.size = sizeof(char) * CHAR_BIT;
- field->event_field.type.u.array.elem_type.u.basic.integer.alignment = lttng_alignof(char) * CHAR_BIT;
- field->event_field.type.u.array.elem_type.u.basic.integer.signedness = lttng_is_signed_type(char);
- field->event_field.type.u.array.elem_type.u.basic.integer.reverse_byte_order = 0;
- field->event_field.type.u.array.elem_type.u.basic.integer.base = 10;
- field->event_field.type.u.array.elem_type.u.basic.integer.encoding = lttng_encode_UTF8;
- field->event_field.type.u.array.length = LTTNG_UST_PROCNAME_LEN;
+ field->event_field.type.atype = atype_array_nestable;
+ field->event_field.type.u.array_nestable.elem_type =
+ &procname_array_elem_type;
+ field->event_field.type.u.array_nestable.length = LTTNG_UST_ABI_PROCNAME_LEN;
field->get_size = procname_get_size;
field->record = procname_record;
field->get_value = procname_get_value;
+ lttng_context_update(*ctx);
return 0;
}