Print environment variables

If OpenSCAP is executed with verbosity level INFO or DEVEL all
environment variable values that can affect OpenSCAP behavior will be
listed at the beginning of the log.

Fixes: #2063

Author: jan-cerny

docs/manual/manual.adoc

@@ -1636,6 +1636,9 @@ not considered local by the scanner:
 
 == List of accepted environment variables
 
+OpenSCAP accepts the following environment variables.
+If OpenSCAP is executed with verbosity level INFO or DEVEL their runtime values will be listed at the beginning of the log.
+
 * `OSCAP_CHECK_ENGINE_PLUGIN_DIR` - Defines path to a directory that contains plug-in libraries implementing additional check engines, eg. SCE.
 * `OSCAP_CONTAINER_VARS` - Additional environment variables read by environmentvariable58_probe. The variables are separated by `\n`. It is used by `oscap-podman` and `oscap-docker` scripts during container scanning.
 * `OSCAP_EVALUATION_TARGET` - Change value of target facts `urn:xccdf:fact:identifier` and `urn:xccdf:fact:asset:identifier:ein` in XCCDF results. Used during offline scanning to pass the name of the target system.

src/common/debug.c

@@ -295,3 +295,27 @@ void __oscap_debuglog_object (const char *file, const char *fn, size_t line, int
 	debug_message_devel_metadata(file, fn, line);
 	debug_message_end();
 }
+
+void oscap_print_env_vars()
+{
+	const char *known_env_vars[] = {
+		"OSCAP_CHECK_ENGINE_PLUGIN_DIR",
+		"OSCAP_CONTAINER_VARS",
+		"OSCAP_EVALUATION_TARGET",
+		"OSCAP_FULL_VALIDATION",
+		"OSCAP_OVAL_COMMAND_OPTIONS",
+		"OSCAP_PCRE_EXEC_RECURSION_LIMIT",
+		"OSCAP_PROBE_ROOT",
+		"SEXP_VALIDATE_DISABLE",
+		"SOURCE_DATE_EPOCH",
+		"OSCAP_PROBE_MEMORY_USAGE_RATIO",
+		"OSCAP_PROBE_MAX_COLLECTED_ITEMS",
+		"OSCAP_PROBE_IGNORE_PATHS",
+		NULL
+	};
+	dI("Using environment variables:");
+	for (int i = 0; known_env_vars[i]; i++) {
+		char *env_var_val = getenv(known_env_vars[i]);
+		dI("%s='%s'", known_env_vars[i], env_var_val ? env_var_val : "");
+	}
+}

src/common/public/oscap_debug.h

@@ -62,6 +62,13 @@ OSCAP_API bool oscap_set_verbose(const char *verbosity_level, const char *filena
  */
 OSCAP_API oscap_verbosity_levels oscap_verbosity_level_from_cstr(const char *level_name);
 
+/**
+ * Print an informational message (verbose level INFO) listing the values
+ * of all environment variables known by oscap.
+ * See the "List of accepted environment variables" section of the OpenSCAP User Manual.
+ */
+OSCAP_API void oscap_print_env_vars(void);
+
 #if defined(_WIN32)
 int setenv(const char *name, const char *value, int overwrite);
 #endif

utils/oscap-tool.c

@@ -386,6 +386,7 @@ int oscap_module_process(struct oscap_module *module, int argc, char **argv)
 			if (!oscap_set_verbose(action.verbosity_level, action.f_verbose_log)) {
 				goto cleanup;
 			}
+            oscap_print_env_vars();
             ret = oscap_module_call(&action);
             goto cleanup;
         }