shellcheck: introduce the --shellcheck-timeout option

... to configure maximum amount of wall-clock time taken by a single
shellcheck process

Related: https://issues.redhat.com/browse/OSH-655
Closes: csutils#182

py/plugins/shellcheck.py

@@ -27,6 +27,8 @@
 FILTER_CMD = "csgrep --mode=json --remove-duplicates --quiet " \
         "--invert-match --event '^note|warning\\[SC1090\\]'"
 
+DEFAULT_SC_TIMEOUT = 30
+
 
 class PluginProps:
     def __init__(self):
@@ -48,6 +50,10 @@ def enable(self):
 
     def init_parser(self, parser):
         csmock.common.util.install_script_scan_opts(parser, "shellcheck")
+        parser.add_argument(
+            "--shellcheck-timeout", type=int, default=DEFAULT_SC_TIMEOUT,
+            help="maximum amount of wall-clock time taken by a single shellcheck process [s]" \
+                f" (defaults to {DEFAULT_SC_TIMEOUT})")
 
     def handle_args(self, parser, args, props):
         if not self.enabled:
@@ -58,7 +64,8 @@ def handle_args(self, parser, args, props):
             parser, args, props, "shellcheck")
 
         props.install_pkgs += ["ShellCheck"]
-        cmd = f"SC_RESULTS_DIR={SHELLCHECK_CAP_DIR} {RUN_SHELLCHECK_SH} {dirs_to_scan}"
+        cmd = f"SC_RESULTS_DIR={SHELLCHECK_CAP_DIR} SC_TIMEOUT={args.shellcheck_timeout} "
+        cmd += f"{RUN_SHELLCHECK_SH} {dirs_to_scan}"
         props.post_build_chroot_cmds += [cmd]
         props.copy_out_files += [SHELLCHECK_CAP_DIR]
 

scripts/run-shellcheck.sh

@@ -8,7 +8,8 @@ export SC_BATCH=1
 export SC_JOBS=$(getconf _NPROCESSORS_ONLN 2>/dev/null || echo 1)
 
 # how long we wait (wall-clock time) for a single shellcheck process to finish
-export SC_TIMEOUT=30
+test -n "$SC_TIMEOUT" || export SC_TIMEOUT=30
+test 0 -lt "$SC_TIMEOUT" || exit $?
 
 # directory for shellcheck results
 test -n "$SC_RESULTS_DIR" || export SC_RESULTS_DIR="./shellcheck-results"