[lttng-dev] [PATCH v3 lttng-ust 2/2] Introduce vtracelog
Maxime Roussin-Belanger
maxime.roussinbelanger at gmail.com
Mon Feb 24 12:34:55 EST 2020
vtracelog works the same as vtracef, but takes a log level
as a parameter and has the same limitations.
Signed-off-by: Maxime Roussin-Belanger <maxime.roussinbelanger at gmail.com>
---
Changes in v3:
* Add this patch
doc/examples/demo-tracelog/Makefile | 14 +++++-
doc/examples/demo-tracelog/demo-vtracelog.c | 53 +++++++++++++++++++++
doc/man/tracelog.3.txt | 9 ++--
include/lttng/tracelog.h | 7 +++
liblttng-ust/tracelog.c | 24 ++++++----
5 files changed, 93 insertions(+), 14 deletions(-)
create mode 100644 doc/examples/demo-tracelog/demo-vtracelog.c
diff --git a/doc/examples/demo-tracelog/Makefile b/doc/examples/demo-tracelog/Makefile
index 0d9a20aa..623979d3 100644
--- a/doc/examples/demo-tracelog/Makefile
+++ b/doc/examples/demo-tracelog/Makefile
@@ -20,18 +20,28 @@ LIBS = -ldl -llttng-ust # On Linux
LOCAL_CPPFLAGS += -I.
AM_V_P := :
-all: demo-tracelog
+all: demo-tracelog demo-vtracelog
demo-tracelog.o: demo-tracelog.c
@if $(AM_V_P); then set -x; else echo " CC $@"; fi; \
$(CC) $(CPPFLAGS) $(LOCAL_CPPFLAGS) $(AM_CFLAGS) $(AM_CPPFLAGS) \
$(CFLAGS) -c -o $@ $<
demo-tracelog: demo-tracelog.o
@if $(AM_V_P); then set -x; else echo " CCLD $@"; fi; \
$(CC) $(LDFLAGS) $(AM_CFLAGS) $(AM_LDFLAGS) $(CFLAGS) \
-o $@ $< $(LIBS)
+demo-vtracelog.o: demo-vtracelog.c
+ @if $(AM_V_P); then set -x; else echo " CC $@"; fi; \
+ $(CC) $(CPPFLAGS) $(LOCAL_CPPFLAGS) $(AM_CFLAGS) $(AM_CPPFLAGS) \
+ $(CFLAGS) -c -o $@ $<
+
+demo-vtracelog: demo-vtracelog.o
+ @if $(AM_V_P); then set -x; else echo " CCLD $@"; fi; \
+ $(CC) $(LDFLAGS) $(AM_CFLAGS) $(AM_LDFLAGS) $(CFLAGS) \
+ -o $@ $< $(LIBS)
+
.PHONY: clean
clean:
- rm -f *.o *.a demo-tracelog
+ rm -f *.o *.a demo-tracelog demo-vtracelog
diff --git a/doc/examples/demo-tracelog/demo-vtracelog.c b/doc/examples/demo-tracelog/demo-vtracelog.c
new file mode 100644
index 00000000..5e7f3884
--- /dev/null
+++ b/doc/examples/demo-tracelog/demo-vtracelog.c
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2020 Maxime Roussin-Belanger <maxime.roussinbelanger at gmail.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; 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 <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <lttng/tracelog.h>
+
+void print_debug(const char* msg, ...)
+{
+ va_list ap;
+ va_start(ap, msg);
+
+ vtracelog(TRACE_DEBUG, msg, ap);
+
+ va_end(ap);
+}
+
+int main(int argc, char **argv)
+{
+ int i;
+ int delay = 0;
+
+ if (argc == 2)
+ delay = atoi(argv[1]);
+
+ fprintf(stderr, "Demo program starting.\n");
+
+ sleep(delay);
+
+ fprintf(stderr, "Tracing... ");
+ for (i = 0; i < 5; i++) {
+ print_debug("Error condition %d", i);
+ }
+ fprintf(stderr, " done.\n");
+ return 0;
+}
diff --git a/doc/man/tracelog.3.txt b/doc/man/tracelog.3.txt
index 1281ce7c..5cf1953a 100644
--- a/doc/man/tracelog.3.txt
+++ b/doc/man/tracelog.3.txt
@@ -15,6 +15,7 @@ SYNOPSIS
[verse]
#define *tracelog*('level', 'fmt', ...)
+#define *vtracelog*('level', 'fmt', 'va_list' ap)
Link with `-llttng-ust`.
@@ -34,9 +35,9 @@ The available values for the 'level' parameter are:
include::log-levels.txt[]
-To use `tracelog()`, include `<lttng/tracelog.h>` where you need it, and
-link your application with `liblttng-ust`. See the <<example,EXAMPLE>>
-section below for a complete usage example.
+To use `tracelog()` or `vtracelog()`, include `<lttng/tracelog.h>` where you
+need it, and link your application with `liblttng-ust`.
+See the <<example,EXAMPLE>> section below for a complete usage example.
Once your application is instrumented with `tracelog()` calls and
ready to run, use man:lttng-enable-event(1) to enable the
@@ -67,7 +68,7 @@ If you do not need to attach a specific log level to a `tracelog()`
call, use man:tracef(3) instead.
See also the <<limitations,LIMITATIONS>> section below for important
-limitations to consider when using `tracelog()`.
+limitations to consider when using `tracelog()` or `vtracelog()`.
[[example]]
diff --git a/include/lttng/tracelog.h b/include/lttng/tracelog.h
index 4309d12e..7aa86809 100644
--- a/include/lttng/tracelog.h
+++ b/include/lttng/tracelog.h
@@ -59,6 +59,13 @@ TP_TRACELOG_CB_TEMPLATE(TRACE_DEBUG);
fmt, ## __VA_ARGS__); \
} while (0)
+#define vtracelog(level, fmt, ap) \
+ do { \
+ if (caa_unlikely(__tracepoint_lttng_ust_tracelog___##level.state)) \
+ _lttng_ust_tracelog_##level(__FILE__, __LINE__, __func__, \
+ fmt, ap); \
+ } while (0)
+
#ifdef __cplusplus
}
#endif
diff --git a/liblttng-ust/tracelog.c b/liblttng-ust/tracelog.c
index 65fc87ed..17546605 100644
--- a/liblttng-ust/tracelog.c
+++ b/liblttng-ust/tracelog.c
@@ -29,27 +29,35 @@
#define TRACEPOINT_DEFINE
#include "lttng-ust-tracelog-provider.h"
+
#define TRACELOG_CB(level) \
- void _lttng_ust_tracelog_##level(const char *file, \
+ void _lttng_ust_vtracelog_##level(const char *file, \
int line, const char *func, \
- const char *fmt, ...) \
+ const char *fmt, va_list ap) \
{ \
- va_list ap; \
- char *msg; \
- int len; \
+ char *msg; \
+ const int len = vasprintf(&msg, fmt, ap); \
\
- va_start(ap, fmt); \
- len = vasprintf(&msg, fmt, ap); \
/* len does not include the final \0 */ \
if (len < 0) \
goto end; \
__tracepoint_cb_lttng_ust_tracelog___##level(file, \
line, func, msg, len, \
LTTNG_UST_CALLER_IP()); \
free(msg); \
end: \
+ return; \
+ } \
+ \
+ void _lttng_ust_tracelog_##level(const char *file, \
+ int line, const char *func, \
+ const char *fmt, ...) \
+ { \
+ va_list ap; \
+ va_start(ap, fmt); \
+ _lttng_ust_vtracelog_##level(file, line, func, fmt, ap); \
va_end(ap); \
- }
+ } \
TRACELOG_CB(TRACE_EMERG)
TRACELOG_CB(TRACE_ALERT)
--
2.20.1
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