Revise usage of print_{error,fatal}()

Let's limit print_fatal() to unexpected conditions.

Also added exit_fatal() to save a few lines of code.

src/common.c

@@ -131,11 +131,19 @@ log_message (int priority, const char *quote, const char *fmt, ...)
 	va_end (ap);
 }
 
+// `fatal' is reserved for unexpected failures that would harm further operation
+
 #define print_fatal(...)    log_message (LOG_ERR,     "fatal: ",   __VA_ARGS__)
 #define print_error(...)    log_message (LOG_ERR,     "error: ",   __VA_ARGS__)
 #define print_warning(...)  log_message (LOG_WARNING, "warning: ", __VA_ARGS__)
 #define print_status(...)   log_message (LOG_INFO,    "-- ",       __VA_ARGS__)
 
+#define exit_fatal(...)                                                        \
+	BLOCK_START                                                                \
+		print_fatal (__VA_ARGS__);                                             \
+		exit (EXIT_FAILURE);                                                   \
+	BLOCK_END
+
 // --- Debugging and assertions ------------------------------------------------
 
 // We should check everything that may possibly fail with at least a soft
@@ -191,10 +199,7 @@ xmalloc (size_t n)
 {
 	void *p = malloc (n);
 	if (!p)
-	{
-		print_fatal ("malloc: %s", strerror (errno));
-		exit (EXIT_FAILURE);
-	}
+		exit_fatal ("malloc: %s", strerror (errno));
 	return p;
 }
 
@@ -203,10 +208,7 @@ xcalloc (size_t n, size_t m)
 {
 	void *p = calloc (n, m);
 	if (!p && n && m)
-	{
-		print_fatal ("calloc: %s", strerror (errno));
-		exit (EXIT_FAILURE);
-	}
+		exit_fatal ("calloc: %s", strerror (errno));
 	return p;
 }
 
@@ -215,10 +217,7 @@ xrealloc (void *o, size_t n)
 {
 	void *p = realloc (o, n);
 	if (!p && n)
-	{
-		print_fatal ("realloc: %s", strerror (errno));
-		exit (EXIT_FAILURE);
-	}
+		exit_fatal ("realloc: %s", strerror (errno));
 	return p;
 }
 
@@ -228,8 +227,7 @@ xreallocarray (void *o, size_t n, size_t m)
 	if (m && n > SIZE_MAX / m)
 	{
 		errno = ENOMEM;
-		print_fatal ("reallocarray: %s", strerror (errno));
-		exit (EXIT_FAILURE);
+		exit_fatal ("reallocarray: %s", strerror (errno));
 	}
 	return xrealloc (o, n * m);
 }
@@ -1170,10 +1168,7 @@ poller_run (struct poller *self)
 	while (n_fds == -1 && errno == EINTR);
 
 	if (n_fds == -1)
-	{
-		print_fatal ("%s: %s", "epoll", strerror (errno));
-		exit (EXIT_FAILURE);
-	}
+		exit_fatal ("%s: %s", "epoll", strerror (errno));
 
 	poller_timers_dispatch (&self->timers);
 
@@ -1312,10 +1307,7 @@ poller_run (struct poller *self)
 	while (result == -1 && errno == EINTR);
 
 	if (result == -1)
-	{
-		print_fatal ("%s: %s", "poll", strerror (errno));
-		exit (EXIT_FAILURE);
-	}
+		exit_fatal ("%s: %s", "poll", strerror (errno));
 
 	poller_timers_dispatch (&self->timers);
 
@@ -1931,7 +1923,7 @@ call_write_default_config (const char *hint, const struct config_item *table)
 	char *filename = write_default_config (hint, prolog, table, &e);
 	if (!filename)
 	{
-		print_fatal ("%s", e->message);
+		print_error ("%s", e->message);
 		error_free (e);
 		exit (EXIT_FAILURE);
 	}