[CRIU] [PATCH v2 2/3] Do not error out in RPC mode with wrong config file entries

[Adrian Reber]

From: Adrian Reber <areber at redhat.com>

Relates: https://github.com/checkpoint-restore/criu/issues/578

If the config parser finds a unknown option in the configuration file,
the wrong option is printed out and CRIU exits.

In RPC mode this is not the best thing to do, as CRIU might not be able
to print the message to the user.

This changes CRIU's behaviour in RPC mode to write a wrong configuration
option to the log file. In CLI mode nothing changes:

$ echo test >> /etc/criu/default.conf
$ criu check
criu: unrecognized option '--test'
$ runc checkpoint <container>
$ grep Unknown dump.log
Warn  (criu/config.c:812): Unknown option encountered: --test
$ echo test-runc >> /etc/criu/runc.conf
$ runc restore -d <container>
$ grep Unknown restore.log
Warn  (criu/config.c:812): Unknown option encountered: --test
Warn  (criu/config.c:812): Unknown option encountered: --test-runc

This way unknown configuration file entries do not break RPC mode, but
they are reported.

Reported-by: Radostin Stoyanov <rstoyanov1 at gmail.com>
Signed-off-by: Adrian Reber <areber at redhat.com>
---
 criu/config.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/criu/config.c b/criu/config.c
index f4fb39b..3c54fa7 100644
--- a/criu/config.c
+++ b/criu/config.c
@@ -31,6 +31,8 @@
 
 struct cr_options opts;
 
+static bool rpc_mode = false;
+
 static int count_elements(char **to_count)
 {
 	int count = 0;
@@ -235,6 +237,20 @@ static int pre_parse(int argc, char **argv, bool *usage_error, bool *no_default_
 		} else if (strstr(argv[i], "--config=") != NULL) {
 			*cfg_file = argv[i] + strlen("--config=");
 			*no_default_config = true;
+		} else if (!strcmp(argv[i], "swrk")) {
+			/*
+			 * In RPC mode we do not want to error out if we
+			 * encounter unknown options. The options can only
+			 * be from a configuration file. To not error out
+			 * because of wrong lines in the configuration file
+			 * this just prints the wrong option into the log.
+			 */
+			rpc_mode = true;
+			/*
+			 * This is only needed so that getopt() does not
+			 * print invalid options to stderr.
+			 */
+			opterr = 0;
 		}
 	}
 
@@ -787,6 +803,28 @@ int parse_options(int argc, char **argv, bool *usage_error,
 		case 'h':
 			*usage_error = false;
 			return 2;
+		case '?':
+			/*
+			 * In RPC mode we do not want to
+			 * error out if an unknown option is found.
+			 * This writes it to the log file and continues.
+			 */
+			if (rpc_mode) {
+				pr_warn("Unknown option encountered: %s\n", _argv[optind - 1]);
+				break;
+			} else {
+				/*
+				 * Only an unknown option that starts with '-' needs to be
+				 * reported to the user. getopt() knows nothing about our
+				 * commands (dump, check, swrk, ...). Those should be
+				 * ignored.
+				 */
+				if (_argv[optind - 1][0] == '-') {
+					*usage_error = true;
+					return 2;
+				}
+			}
+			break;
 		default:
 			return 2;
 		}
-- 
1.8.3.1