Clarify error handling.

While working with nbd-server, I tried to allow the clients to
fetch a list of exports. After including the following in the
generic section of /etc/nbd-server/config:
	[generic]
		# other lines ...
		allowlist
nbd-server refused to start, complaining there were no configured
exports, even though there were:
	nass0:root ~ 17 # nbd-server -d
	** Message: No configured exports; quitting.

Obviously, the line should read 'allowlist = 1', but It would be
helpful if nbd-server detected the error, and complained about
that instead of (apparently) ignoring the rest of the config file,
and issuing the confusing complaint about no configured exports.

I also tried 'allowlist = yes'. In that case it gives a
descriptive message, although it still confusingly and incorrectly
complains that there are no exports:
	nass0:root ~ 14 # nbd-server -d

	** (process:3482): WARNING **: Could not parse config file: Could not parse allowlist in group
generic: Key file contains key 'allowlist' which has a value that cannot be interpreted.
	** Message: No configured exports; quitting.

The cause seems to be that g_key_file_load_from_file fails not only
if the file cannot be found or read, but also if it contains syntax
errors.

Original patch by Rogier <rogier777@gmail.com>, but reworked enough by
$SELF that it isn't the same thing anymore.

diff --git a/nbd-server.c b/nbd-server.c
index e905281d191c56791979d6ae32e12ee852f34373..9408a5b0a2e57e1b0dca857bd66e9869362f19ce 100644 (file)
--- a/nbd-server.c
+++ b/nbd-server.c
@@ -905,7 +905,8 @@ GArray* parse_cfile(gchar* f, struct generic_conf *const genconf, GError** e) {
        retval = g_array_new(FALSE, TRUE, sizeof(SERVER));
        if(!g_key_file_load_from_file(cfile, f, G_KEY_FILE_KEEP_COMMENTS |
                        G_KEY_FILE_KEEP_TRANSLATIONS, &err)) {
-               g_set_error(e, NBDS_ERR, NBDS_ERR_CFILE_NOTFOUND, "Could not open config file %s.", f);
+               g_set_error(e, NBDS_ERR, NBDS_ERR_CFILE_NOTFOUND, "Could not open config file %s: %s",
+                               f, err->message);
                g_key_file_free(cfile);
                return retval;
        }
@@ -2774,7 +2775,8 @@ int main(int argc, char *argv[]) {
        }
 
        if((!serve) && (!servers||!servers->len)) {
-               g_message("No configured exports; quitting.");
+               if(err)
+                       g_message("No configured exports; quitting.");
                exit(EXIT_FAILURE);
        }
        if (!dontfork)