vtracef accepts a va_list argument to simplify tracing
functions which use a va_list
Here's an example from wpa_supplicant that I wanted to
trace:
void wpa_debug(int level, const char* fmt, ...) {
va_list ap;
va_start(ap, fmt);
...
// The call I want to easily trace with vtracef
vprintf(fmt, ap);
...
va_end(ap);
}
wpa_debug is used a fair amount and it would be annoying to
replace all the wpa_debug calls with tracef.
With vtracef, it simplifies the find and replace effort by
only changing it at one place.
Signed-off-by: Maxime Roussin-Belanger <maxime.roussinbelan...@gmail.com>
---
include/lttng/tracef.h | 10 ++++++++++
liblttng-ust/tracef.c | 18 +++++++++++-------
2 files changed, 21 insertions(+), 7 deletions(-)
diff --git a/include/lttng/tracef.h b/include/lttng/tracef.h
index 0c59c9ae..e3a7587d 100644
--- a/include/lttng/tracef.h
+++ b/include/lttng/tracef.h
@@ -32,13 +32,23 @@ extern "C" {
extern
void _lttng_ust_tracef(const char *fmt, ...);
+extern
+void _lttng_ust_vtracef(const char *fmt, va_list ap);
+
#define tracef(fmt, ...) \
do { \
LTTNG_STAP_PROBEV(tracepoint_lttng_ust_tracef, event, ##
__VA_ARGS__); \
if (caa_unlikely(__tracepoint_lttng_ust_tracef___event.state)) \
_lttng_ust_tracef(fmt, ## __VA_ARGS__); \
} while (0)
+#ifndef LTTNG_UST_HAVE_SDT_INTEGRATION
+#define vtracef(fmt, ap) \
+ do { \
+ if (caa_unlikely(__tracepoint_lttng_ust_tracef___event.state)) \
+ _lttng_ust_vtracef(fmt, ap); \
+ } while (0)
+#endif
#ifdef __cplusplus
}
#endif
diff --git a/liblttng-ust/tracef.c b/liblttng-ust/tracef.c
index ea98e43e..2a809eed 100644
--- a/liblttng-ust/tracef.c
+++ b/liblttng-ust/tracef.c
@@ -29,20 +29,24 @@
#define TRACEPOINT_DEFINE
#include "lttng-ust-tracef-provider.h"
-void _lttng_ust_tracef(const char *fmt, ...)
+void _lttng_ust_vtracef(const char *fmt, va_list ap)
{
- va_list ap;
char *msg;
- int len;
-
- va_start(ap, fmt);
- len = vasprintf(&msg, fmt, ap);
+ const int len = vasprintf(&msg, fmt, ap);
/* len does not include the final \0 */
if (len < 0)
- goto end;
+ return;
__tracepoint_cb_lttng_ust_tracef___event(msg, len,
LTTNG_UST_CALLER_IP());
free(msg);
+}
+
+void _lttng_ust_tracef(const char *fmt, ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ _lttng_ust_vtracef(fmt, ap);
end:
va_end(ap);
}
--
2.20.1
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