ksmbd-tools: add smb.conf fallback functionality

Give existing users a chance to switch from `sysconfdir/ksmbd/smb.conf'
to `sysconfdir/ksmbd/ksmbd.conf' by falling back to the former if the
latter does not exist. This fallback functionality may be removed in
any future release.

Signed-off-by: atheik <atteh.mailbox@gmail.com>

include/ksmbdtools.h

@@ -84,9 +84,10 @@ extern struct smbconf_global global_conf;
 
 #define KSMBD_CONF_FILE_MAX		10000
 
-#define PATH_PWDDB	SYSCONFDIR "/ksmbd/ksmbdpwd.db"
-#define PATH_SMBCONF	SYSCONFDIR "/ksmbd/ksmbd.conf"
-#define PATH_SUBAUTH	SYSCONFDIR "/ksmbd/ksmbd.subauth"
+#define PATH_PWDDB		SYSCONFDIR "/ksmbd/ksmbdpwd.db"
+#define PATH_SMBCONF		SYSCONFDIR "/ksmbd/ksmbd.conf"
+#define PATH_SMBCONF_FALLBACK	SYSCONFDIR "/ksmbd/smb.conf"
+#define PATH_SUBAUTH		SYSCONFDIR "/ksmbd/ksmbd.subauth"
 
 #define KSMBD_HEALTH_START		(0)
 #define KSMBD_HEALTH_RUNNING		(1 << 0)

lib/config_parser.c

@@ -705,11 +705,22 @@ int cp_parse_pwddb(const char *pwddb)
 
 int cp_smbconfig_hash_create(const char *smbconf)
 {
-	int ret = init_smbconf_parser();
+	int ret;
 
+	ret = init_smbconf_parser();
 	if (ret)
 		return ret;
-	return __mmap_parse_file(smbconf, process_smbconf_entry);
+
+	ret = __mmap_parse_file(smbconf, process_smbconf_entry);
+	if (ret == -ENOENT && !strcmp(smbconf, PATH_SMBCONF)) {
+		ret = __mmap_parse_file(PATH_SMBCONF_FALLBACK,
+					process_smbconf_entry);
+		if (!ret)
+			pr_err("Use of `%s' is deprecated, rename it to `%s' now!\n",
+					PATH_SMBCONF_FALLBACK, PATH_SMBCONF);
+	}
+
+	return ret;
 }
 
 int cp_parse_subauth(void)