Improve diagnostic output.

* src/diag.c (diag_output): New variable.
(diag_setup): New function.
(vlogmsg): Use diag_output to decide where to
output the message. Output to both stderr and
syslog if diag_output says so.
* src/pies.c (log_to_stderr): Rename to log_to_stderr_only.
All uses changed.
(log_setup): Remove.
(main): Use diag_setup to initialize diagnostics.
* src/pies.h (log_to_stderr): Remove.
(DIAG_TO_SYSLOG, DIAG_TO_STDERR): New defines.
(diag_setup): New function.

1 files changed, 13 insertions, 2 deletions

diff --git a/src/diag.c b/src/diag.c
index b2b4b31..0aebb7a 100644
--- a/src/diag.c
+++ b/src/diag.c
@@ -19,6 +19,16 @@
 
 unsigned debug_level;
 int source_info_option;
+int diag_output = DIAG_TO_STDERR;
+
+void
+diag_setup (int flags)
+{
+  if (flags)
+    diag_output = flags;
+  if (diag_output & DIAG_TO_SYSLOG)
+    openlog (log_tag, LOG_PID, log_facility);
+}
 
 void
 syslog_printer (int prio, const char *fmt, va_list ap)
@@ -35,12 +45,13 @@ syslog_printer (int prio, const char *fmt, va_list ap)
 void
 vlogmsg (int prio, const char *fmt, va_list ap)
 {
-  if (log_to_stderr)
+  if (DIAG_OUTPUT (DIAG_TO_STDERR))
     {
+      fprintf (stderr, "%s: ", program_name);
       vfprintf (stderr, fmt, ap);
       fprintf (stderr, "\n");
     }
-  else
+  if (DIAG_OUTPUT (DIAG_TO_SYSLOG))
     syslog_printer (prio, fmt, ap);
 }