selftests/bpf: Silence ima_setup.sh when not running in verbose mode.

Currently, ima_setup.sh spews outputs from commands like mkfs and dd
on the terminal without taking into account the verbosity level of
the test framework. Update test_progs to set the environment variable
SELFTESTS_VERBOSE=1 when a verbose output is requested. This
environment variable is then used by ima_setup.sh (and can be used by
other similar scripts) to obey the verbosity level of the test harness
without needing to re-implement command line options for verbosity.

In "silent" mode, the script saves the output to a temporary file, the
contents of which are echoed back to stderr when the script encounters
an error.

Fixes: 34b82d3a ("bpf: Add a selftest for bpf_ima_inode_hash")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201211010711.3716917-1-kpsingh@kernel.org

tools/testing/selftests/bpf/ima_setup.sh

@@ -7,6 +7,8 @@ set -o pipefail
 
 IMA_POLICY_FILE="/sys/kernel/security/ima/policy"
 TEST_BINARY="/bin/true"
+VERBOSE="${SELFTESTS_VERBOSE:=0}"
+LOG_FILE="$(mktemp /tmp/ima_setup.XXXX.log)"
 
 usage()
 {
@@ -75,6 +77,19 @@ run()
 	exec "${copied_bin_path}"
 }
 
+catch()
+{
+	local exit_code="$1"
+	local log_file="$2"
+
+	if [[ "${exit_code}" -ne 0 ]]; then
+		cat "${log_file}" >&3
+	fi
+
+	rm -f "${log_file}"
+	exit ${exit_code}
+}
+
 main()
 {
 	[[ $# -ne 2 ]] && usage
@@ -96,4 +111,13 @@ main()
 	fi
 }
 
+trap 'catch "$?" "${LOG_FILE}"' EXIT
+
+if [[ "${VERBOSE}" -eq 0 ]]; then
+	# Save the stderr to 3 so that we can output back to
+	# it incase of an error.
+	exec 3>&2 1>"${LOG_FILE}" 2>&1
+fi
+
 main "$@"
+rm -f "${LOG_FILE}"

tools/testing/selftests/bpf/test_progs.c

@@ -587,6 +587,16 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
 				return -EINVAL;
 			}
 		}
+
+		if (env->verbosity > VERBOSE_NONE) {
+			if (setenv("SELFTESTS_VERBOSE", "1", 1) == -1) {
+				fprintf(stderr,
+					"Unable to setenv SELFTESTS_VERBOSE=1 (errno=%d)",
+					errno);
+				return -1;
+			}
+		}
+
 		break;
 	case ARG_GET_TEST_CNT:
 		env->get_test_cnt = true;