[PATCH] log: Don't duplicate messages on stderr before daemonising

[Stefano Brivio <sbrivio@redhat.com>]

Now that logging functions force printing messages to stderr before
passt forks to background, we'll have duplicate messages when running
from an interactive terminal, or if --stderr is passed, because at
some point we set LOG_PERROR in our __openlog() wrapper.

We could defer setting LOG_PERROR, but that would change option
semantics in other, unexpected ways. We could force calling
passt_vsyslog() as long as the mask is set to LOG_EMERG, but that
complicates the logic in logging functions even further.

Go the easy way for now: don't force printing to stderr with
LOG_EMERG if LOG_PERROR is already set. We should seriously consider a
rework of those logging functions at this point.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
This applies on top of Laine's series.

 log.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/log.c b/log.c
index 785bc36..f23e8ef 100644
--- a/log.c
+++ b/log.c
@@ -44,6 +44,8 @@ static char	log_header[BUFSIZ];	/* File header, written back on cuts */
 static time_t	log_start;		/* Start timestamp */
 int		log_trace;		/* --trace mode enabled */
 
+#define BEFORE_DAEMON		(setlogmask(0) == LOG_MASK(LOG_EMERG))
+
 #define logfn(name, level, doexit)					\
 void name(const char *format, ...) {					\
 	struct timespec tp;						\
@@ -56,8 +58,7 @@ void name(const char *format, ...) {					\
 			tp.tv_nsec / (100L * 1000));			\
 	}								\
 									\
-	if ((LOG_MASK(LOG_PRI(level)) & log_mask) ||			\
-	    setlogmask(0) == LOG_MASK(LOG_EMERG)) {			\
+	if ((LOG_MASK(LOG_PRI(level)) & log_mask) || BEFORE_DAEMON) {	\
 		va_start(args, format);					\
 		if (log_file != -1)					\
 			logfile_write(level, format, args);		\
@@ -67,7 +68,7 @@ void name(const char *format, ...) {					\
 	}								\
 									\
 	if ((setlogmask(0) & LOG_MASK(LOG_DEBUG) && log_file == -1) ||	\
-	     setlogmask(0) == LOG_MASK(LOG_EMERG)) {			\
+	    (BEFORE_DAEMON && !(log_opt & LOG_PERROR))) {		\
 		va_start(args, format);					\
 		(void)vfprintf(stderr, format, args); 			\
 		va_end(args);						\
-- 
@@ -44,6 +44,8 @@ static char	log_header[BUFSIZ];	/* File header, written back on cuts */
 static time_t	log_start;		/* Start timestamp */
 int		log_trace;		/* --trace mode enabled */
 
+#define BEFORE_DAEMON		(setlogmask(0) == LOG_MASK(LOG_EMERG))
+
 #define logfn(name, level, doexit)					\
 void name(const char *format, ...) {					\
 	struct timespec tp;						\
@@ -56,8 +58,7 @@ void name(const char *format, ...) {					\
 			tp.tv_nsec / (100L * 1000));			\
 	}								\
 									\
-	if ((LOG_MASK(LOG_PRI(level)) & log_mask) ||			\
-	    setlogmask(0) == LOG_MASK(LOG_EMERG)) {			\
+	if ((LOG_MASK(LOG_PRI(level)) & log_mask) || BEFORE_DAEMON) {	\
 		va_start(args, format);					\
 		if (log_file != -1)					\
 			logfile_write(level, format, args);		\
@@ -67,7 +68,7 @@ void name(const char *format, ...) {					\
 	}								\
 									\
 	if ((setlogmask(0) & LOG_MASK(LOG_DEBUG) && log_file == -1) ||	\
-	     setlogmask(0) == LOG_MASK(LOG_EMERG)) {			\
+	    (BEFORE_DAEMON && !(log_opt & LOG_PERROR))) {		\
 		va_start(args, format);					\
 		(void)vfprintf(stderr, format, args); 			\
 		va_end(args);						\
-- 
2.35.1