[PATCH 3/8] trace-cmd library: Add log levels

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

Add levels to library logs and introduce a new API to set the desired
log severity:
 tracecmd_set_loglevel()
When a new trace-cmd library log level is set, propagate it to tracefs
and traceevent libraries as well.
Removed the "weak" definition of the library log functions. Setting
the desired log level can be used to silence the library logs, instead
of overwriting the log functions.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/trace-cmd/trace-cmd.h           |  2 ++
 lib/trace-cmd/include/trace-cmd-local.h |  1 -
 lib/trace-cmd/trace-util.c              | 26 ++++++++++++++++++++++---
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 162cd318..1cfdc4af 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -41,4 +41,6 @@ int tracecmd_buffer_instances(struct tracecmd_input *handle);
 const char *tracecmd_buffer_instance_name(struct tracecmd_input *handle, int indx);
 struct tracecmd_input *tracecmd_buffer_instance_handle(struct tracecmd_input *handle, int indx);
 
+void tracecmd_set_loglevel(enum tep_loglevel level);
+
 #endif /* _TRACE_CMD_H */
diff --git a/lib/trace-cmd/include/trace-cmd-local.h b/lib/trace-cmd/include/trace-cmd-local.h
index cd868f60..76179148 100644
--- a/lib/trace-cmd/include/trace-cmd-local.h
+++ b/lib/trace-cmd/include/trace-cmd-local.h
@@ -9,7 +9,6 @@
 #include <byteswap.h>
 #include "trace-cmd-private.h"
 
-/* Can be overridden */
 void tracecmd_warning(const char *fmt, ...);
 void tracecmd_fatal(const char *fmt, ...);
 void tracecmd_info(const char *fmt, ...);
diff --git a/lib/trace-cmd/trace-util.c b/lib/trace-cmd/trace-util.c
index 77259357..6f9da7c7 100644
--- a/lib/trace-cmd/trace-util.c
+++ b/lib/trace-cmd/trace-util.c
@@ -30,7 +30,7 @@
 #define PROC_STACK_FILE "/proc/sys/kernel/stack_tracer_enabled"
 
 static bool debug;
-
+static int log_level = TEP_LOG_CRITICAL;
 static FILE *logfp;
 
 const static struct {
@@ -355,10 +355,24 @@ trace_load_plugins(struct tep_handle *tep, int flags)
 	return list;
 }
 
-void __weak tracecmd_warning(const char *fmt, ...)
+/**
+ * tracecmd_set_loglevel - set log level of the library
+ * @level: desired level of the library messages
+ */
+void tracecmd_set_loglevel(enum tep_loglevel level)
+{
+	log_level = level;
+	tracefs_set_loglevel(level);
+	tep_set_loglevel(level);
+}
+
+void tracecmd_warning(const char *fmt, ...)
 {
 	va_list ap;
 
+	if (log_level < TEP_LOG_WARNING)
+		return;
+
 	va_start(ap, fmt);
 	tep_vprint("libtracecmd", TEP_LOG_WARNING, fmt, ap);
 	va_end(ap);
@@ -368,17 +382,23 @@ void tracecmd_info(const char *fmt, ...)
 {
 	va_list ap;
 
+	if (log_level < TEP_LOG_INFO)
+		return;
+
 	va_start(ap, fmt);
 	tep_vprint("libtracecmd", TEP_LOG_INFO, fmt, ap);
 	va_end(ap);
 }
 
 
-void __weak tracecmd_fatal(const char *fmt, ...)
+void tracecmd_fatal(const char *fmt, ...)
 {
 	int ret;
 	va_list ap;
 
+	if (log_level < TEP_LOG_CRITICAL)
+		return;
+
 	va_start(ap, fmt);
 	ret = tep_vprint("libtracecmd", TEP_LOG_CRITICAL, fmt, ap);
 	va_end(ap);
-- 
2.30.2