comsat: provide a fine-grained control over where biffrc errors are output

* comsat/comsat.c (biffrc_errors): New variable.
(comsat_cfg_param): New statements: biffrc-errors-to-tty and
biffrc-errors-to-err
(main): In test mode, set biffrc_errors to BIFFRC_ERRORS_TO_ERR.
* comsat/comsat.h (BIFFRC_ERRORS_TO_TTY)
(BIFFRC_ERRORS_TO_ERR): New flags.
(biffrc_errors): New variable.
* comsat/action.c (report_error): Consult biffrc_errors.

@@ -314,15 +314,19 @@ struct biffrc_environ
 static void
 report_error (struct biffrc_environ *env, const char *fmt, ...)
 {
+  if (biffrc_errors)
+    {
       va_list ap;
       va_start (ap, fmt);
       mu_vasnprintf (&env->errbuf, &env->errsize, fmt, ap);
+      if (biffrc_errors & BIFFRC_ERRORS_TO_TTY)
 	mu_stream_printf (env->logstr, "%s\n", env->errbuf);
+      if (biffrc_errors & BIFFRC_ERRORS_TO_ERR)
 	mu_diag_output (MU_DIAG_ERROR, "%s", env->errbuf);
       va_end (ap);
+    }
 }
 
-  
 static void
 action_beep (struct biffrc_environ *env, size_t argc, char **argv)
 {

@@ -54,7 +54,7 @@ typedef struct utmp UTMP;
 #define MAX_TTY_SIZE (sizeof (PATH_TTY_PFX) + sizeof (((UTMP*)0)->ut_line))
 
 const char *program_version = "comsatd (" PACKAGE_STRING ")";
-static char doc[] = N_("GNU comsatd -- the Comsat daemon.");
+static char doc[] = N_("GNU comsatd -- notify users about incoming mail");
 static char args_doc[] = N_("\n--test MBOX-URL MSG-QID");
 
 #define OPT_FOREGROUND 256
@@ -100,6 +100,7 @@ int maxlines = 5;
 char *hostname;
 const char *username;
 int require_tty;
+int biffrc_errors = BIFFRC_ERRORS_TO_TTY | BIFFRC_ERRORS_TO_ERR;
 mu_m_server_t server;
 
 static void comsat_init (void);
@@ -114,11 +115,45 @@ static int reload = 0;
 int test_mode;
 char *biffrc = BIFF_RC;
 
+static int
+biffrc_error_ctl (mu_config_value_t *val, int flag)
+{
+  int res;
+  
+  if (mu_cfg_assert_value_type (val, MU_CFG_STRING))
+    return 1;
+  if (mu_cfg_parse_boolean (val->v.string, &res))
+    mu_diag_output (MU_LOG_ERROR, _("not a boolean"));
+  else if (res)
+    biffrc_errors |= flag;
+  else
+    biffrc_errors &= ~flag;
+  return 0;
+}
+    
+static int
+cb_biffrc_errors_to_tty (void *data, mu_config_value_t *val)
+{
+  return biffrc_error_ctl (val, BIFFRC_ERRORS_TO_TTY);
+}
+
+static int
+cb_biffrc_errors_to_err (void *data, mu_config_value_t *val)
+{
+  return biffrc_error_ctl (val, BIFFRC_ERRORS_TO_ERR);
+}
+
 struct mu_cfg_param comsat_cfg_param[] = {
   { "allow-biffrc", mu_cfg_bool, &allow_biffrc, 0, NULL,
     N_("Read .biffrc file from the user home directory.") },
   { "require-tty", mu_cfg_bool, &require_tty, 0, NULL,
     N_("Notify only if the user is logged on one of the ttys.") },
+  { "biffrc-errors-to-tty", mu_cfg_callback, NULL, 0, cb_biffrc_errors_to_tty,
+    N_("Send biffrc errors to user's tty."),
+    N_("arg: bool") },
+  { "biffrc-errors-to-err", mu_cfg_callback, NULL, 0, cb_biffrc_errors_to_err,
+    N_("Send biffrc errors to Mailutils error output."),
+    N_("arg: bool") },
   { "max-lines", mu_cfg_int, &maxlines, 0, NULL,
     N_("Maximum number of message body lines to be output.") },
   { "max-requests", mu_cfg_uint, &maxrequests, 0, NULL,
@@ -548,6 +583,7 @@ main (int argc, char **argv)
       argv += ind;
   
       mu_stdstream_strerr_setup (MU_STRERR_STDERR);
+      biffrc_errors = BIFFRC_ERRORS_TO_ERR;
       if (argc < 2 || argc > 2)
 	{
 	  mu_error (_("mailbox URL and message QID are required in test mode"));

@@ -68,6 +68,10 @@
 
 #define BIFF_RC ".biffrc"
 
+/* Where to report biffrc errors to: */
+#define BIFFRC_ERRORS_TO_TTY 0x01  /* Send them to the user's tty */
+#define BIFFRC_ERRORS_TO_ERR 0x02  /* Send them to strerr */
+
 extern int allow_biffrc;
 extern unsigned maxrequests;
 extern time_t request_control_interval;
@@ -78,6 +82,7 @@ extern const char *username;
 extern char *hostname;
 extern struct daemon_param daemon_param;
 extern char *biffrc;
+extern int biffrc_errors;
 
 void run_user_action (const char *device, mu_message_t msg);