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

[Adrian Reber]

So this fails in CI because we have a test to make sure RPC correctly
detects wrong configuration file entries:

$ ./config_file.py /tmp
Connecting to CRIU in swrk mode.
FAIL: CRIU should have returned 1 instead of -9

So, not sure if we actually want to skip wrong entries in the
configuration file. Any preferences? How should we handle wrong entries
in configuration files in RPC mode?

		Adrian

On Fri, Nov 30, 2018 at 11:51:37AM +0000, Adrian Reber wrote:
> 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
> 
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> CRIU at openvz.org
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		Adrian

-- 
Adrian Reber <adrian at lisas.de>            http://lisas.de/~adrian/
Creating computer software is always a demanding and painstaking
process -- an exercise in logic, clear expression, and almost fanatical
attention to detail.  It requires intelligence, dedication, and an
enormous amount of hard work.  But, a certain amount of unpredictable
and often unrepeatable inspiration is what usually makes the difference
between adequacy and excellence.