[PATCH v2 1/9] log to stderr until process is daemonized, even if a logfile is set

[Laine Stump <laine@redhat.com>]

Signed-off-by: Laine Stump <laine@redhat.com>
---
 log.c   | 14 +++++++++++++-
 log.h   |  1 +
 passt.c |  6 ++++--
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/log.c b/log.c
index 468c730..0ab0adf 100644
--- a/log.c
+++ b/log.c
@@ -34,6 +34,7 @@ static int	log_sock = -1;		/* Optional socket to system logger */
 static char	log_ident[BUFSIZ];	/* Identifier string for openlog() */
 static int	log_mask;		/* Current log priority mask */
 static int	log_opt;		/* Options for openlog() */
+static int	log_daemon_mode = false; /* true once process is daemonized */
 
 static int	log_file = -1;		/* Optional log file descriptor */
 static size_t	log_size;		/* Maximum log file size in bytes */
@@ -67,7 +68,8 @@ void name(const char *format, ...) {					\
 	}								\
 									\
 	if ((setlogmask(0) & LOG_MASK(LOG_DEBUG) ||			\
-	     setlogmask(0) == LOG_MASK(LOG_EMERG)) && log_file == -1) {	\
+	     setlogmask(0) == LOG_MASK(LOG_EMERG))			\
+	     && (log_file == -1 || !log_daemon_mode)) {			\
 		va_start(args, format);					\
 		(void)vfprintf(stderr, format, args); 			\
 		va_end(args);						\
@@ -91,6 +93,16 @@ logfn(warn,  LOG_WARNING)
 logfn(info,  LOG_INFO)
 logfn(debug, LOG_DEBUG)
 
+/**
+ * log_go_daemon() - tell logging subsystem that the process has been
+ *		     been daemonized, so it stop logging to stderr
+ *		     if appropriate.
+ */
+void log_go_daemon(void)
+{
+	log_daemon_mode = true;
+}
+
 /**
  * trace_init() - Set log_trace depending on trace (debug) mode
  * @enable:	Tracing debug mode enabled if non-zero
diff --git a/log.h b/log.h
index 987dc17..a57c777 100644
--- a/log.h
+++ b/log.h
@@ -25,6 +25,7 @@ void trace_init(int enable);
 
 void __openlog(const char *ident, int option, int facility);
 void logfile_init(const char *name, const char *path, size_t size);
+void log_go_daemon(void);
 void passt_vsyslog(int pri, const char *format, va_list ap);
 void logfile_write(int pri, const char *format, va_list ap);
 void __setlogmask(int mask);
diff --git a/passt.c b/passt.c
index 8b2c50d..cf010e8 100644
--- a/passt.c
+++ b/passt.c
@@ -296,10 +296,12 @@ int main(int argc, char **argv)
 		exit(EXIT_FAILURE);
 	}
 
-	if (!c.foreground)
+	if (!c.foreground) {
 		__daemon(pidfile_fd, devnull_fd);
-	else
+		log_go_daemon();
+	} else {
 		write_pidfile(pidfile_fd, getpid());
+	}
 
 	isolate_postfork(&c);
 
-- 
@@ -296,10 +296,12 @@ int main(int argc, char **argv)
 		exit(EXIT_FAILURE);
 	}
 
-	if (!c.foreground)
+	if (!c.foreground) {
 		__daemon(pidfile_fd, devnull_fd);
-	else
+		log_go_daemon();
+	} else {
 		write_pidfile(pidfile_fd, getpid());
+	}
 
 	isolate_postfork(&c);
 
-- 
2.39.1