From 16d5dff5964fa61636a96d574d33b4fa3bc4c55a Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Wed, 15 Jul 2020 11:29:43 +0200
Subject: [PATCH] libnm: support "stdout" flag for LIBNM_CLIENT_DEBUG for
 logging to stdout

Trace logging from libnm is verbose. So, by default we print trace
messages to stderr. However, that means that messages printed to stdout
are not in sync with the trace logging.

That means, if the libnm application prints messages to stdout, and
you'd like to correlate them with trace messages, it is difficult.

Add an option to allow printing trace messages to stdout.

  $ LIBNM_CLIENT_DEBUG=trace,stdout nmcli

Possibly redirecting stderr to stdout might also work around the
ordering issue. However, it's not entirely clear how buffering of
the file streams affects this.
---
 libnm/nm-libnm-utils.c | 20 +++++++++++++++-----
 libnm/nm-libnm-utils.h | 20 ++++++++++++++++----
 2 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/libnm/nm-libnm-utils.c b/libnm/nm-libnm-utils.c
index f8d1ff560c..c818e5bdb7 100644
--- a/libnm/nm-libnm-utils.c
+++ b/libnm/nm-libnm-utils.c
@@ -24,6 +24,7 @@ _nml_dbus_log_level_init (void)
 		{ "debug",   _NML_DBUS_LOG_LEVEL_DEBUG },
 		{ "warning", _NML_DBUS_LOG_LEVEL_WARN },
 		{ "error",   _NML_DBUS_LOG_LEVEL_ERROR },
+		{ "stdout",  NML_DBUS_LOG_STDOUT },
 	};
 	int l;
 
@@ -41,6 +42,7 @@ _nml_dbus_log_level_init (void)
 
 void
 _nml_dbus_log (NMLDBusLogLevel level,
+               gboolean use_stdout,
                const char *fmt,
                ...) {
 	NMLDBusLogLevel configured_log_level;
@@ -91,11 +93,19 @@ _nml_dbus_log (NMLDBusLogLevel level,
 
 	ts = nm_utils_clock_gettime_nsec (CLOCK_BOOTTIME);
 
-	g_printerr ("libnm-dbus: %s[%"G_GINT64_FORMAT".%05"G_GINT64_FORMAT"] %s\n",
-	            prefix,
-	            ts / NM_UTILS_NSEC_PER_SEC,
-	            (ts / (NM_UTILS_NSEC_PER_SEC / 10000)) % 10000,
-	            msg);
+	if (use_stdout) {
+		g_print ("libnm-dbus: %s[%"G_GINT64_FORMAT".%05"G_GINT64_FORMAT"] %s\n",
+		         prefix,
+		         ts / NM_UTILS_NSEC_PER_SEC,
+		         (ts / (NM_UTILS_NSEC_PER_SEC / 10000)) % 10000,
+		         msg);
+	} else {
+		g_printerr ("libnm-dbus: %s[%"G_GINT64_FORMAT".%05"G_GINT64_FORMAT"] %s\n",
+		            prefix,
+		            ts / NM_UTILS_NSEC_PER_SEC,
+		            (ts / (NM_UTILS_NSEC_PER_SEC / 10000)) % 10000,
+		            msg);
+	}
 }
 
 /*****************************************************************************/
diff --git a/libnm/nm-libnm-utils.h b/libnm/nm-libnm-utils.h
index 5a5a5d77eb..acc4458f0d 100644
--- a/libnm/nm-libnm-utils.h
+++ b/libnm/nm-libnm-utils.h
@@ -55,6 +55,8 @@ typedef enum {
 	                                  | NML_DBUS_LOG_LEVEL_DEBUG,
 	NML_DBUS_LOG_LEVEL_ERROR        =   _NML_DBUS_LOG_LEVEL_ERROR
 	                                  | NML_DBUS_LOG_LEVEL_WARN,
+
+	NML_DBUS_LOG_STDOUT             = 0x20,
 } NMLDBusLogLevel;
 
 #undef _LOGL_TRACE
@@ -74,7 +76,7 @@ extern volatile int _nml_dbus_log_level;
 int _nml_dbus_log_level_init (void);
 
 static inline gboolean
-nml_dbus_log_enabled (NMLDBusLogLevel level)
+nml_dbus_log_enabled_full (NMLDBusLogLevel level, gboolean *out_use_stdout)
 {
 	int l;
 
@@ -90,25 +92,35 @@ nml_dbus_log_enabled (NMLDBusLogLevel level)
 		l = _nml_dbus_log_level_init ();
 
 	nm_assert (l & _NML_DBUS_LOG_LEVEL_INITIALIZED);
+	NM_SET_OUT (out_use_stdout, NM_FLAGS_HAS (l, NML_DBUS_LOG_STDOUT));
 	if (level == NML_DBUS_LOG_LEVEL_ANY)
 		return l != _NML_DBUS_LOG_LEVEL_INITIALIZED;
 	return !!(((NMLDBusLogLevel) l) & level);
 }
 
+static inline gboolean
+nml_dbus_log_enabled (NMLDBusLogLevel level)
+{
+	return nml_dbus_log_enabled_full (level, NULL);
+}
+
 void _nml_dbus_log (NMLDBusLogLevel level,
+                    gboolean use_stdout,
                     const char *fmt,
-                    ...) _nm_printf (2, 3);
+                    ...) _nm_printf (3, 4);
 
 #define NML_DBUS_LOG(level, ...) \
 	G_STMT_START { \
+		gboolean _use_stdout; \
+		\
 		G_STATIC_ASSERT (   (level) == _NML_DBUS_LOG_LEVEL_NONE \
 		                 || (level) == NML_DBUS_LOG_LEVEL_TRACE \
 		                 || (level) == NML_DBUS_LOG_LEVEL_DEBUG \
 		                 || (level) == NML_DBUS_LOG_LEVEL_WARN \
 		                 || (level) == NML_DBUS_LOG_LEVEL_ERROR); \
 		\
-		if (nml_dbus_log_enabled (level)) { \
-			_nml_dbus_log ((level), __VA_ARGS__); \
+		if (nml_dbus_log_enabled_full (level, &_use_stdout)) { \
+			_nml_dbus_log ((level), _use_stdout, __VA_ARGS__); \
 		} \
 	} G_STMT_END