[PATCH blktests v2 1/2] check, common/rc: support normal user privilege

[Shin'ichiro Kawasaki]

To run commands with normal user privilege, add a new config variable
NORMAL_USER and two helper functions _run_user and _require_normal_user.
The user name specified to NORMAL_USER is used to run the commands
specified to _run_user. The test cases which require NORMAL_USER shall
call _require_normal_user to ensure the NORMAL_USER is valid.

Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki at wdc.com>
---
 Documentation/running-tests.md | 10 ++++++++++
 check                          |  1 +
 common/rc                      | 13 +++++++++++++
 3 files changed, 24 insertions(+)

diff --git a/Documentation/running-tests.md b/Documentation/running-tests.md
index 586be0b..3550f37 100644
--- a/Documentation/running-tests.md
+++ b/Documentation/running-tests.md
@@ -113,6 +113,16 @@ use_siw=1 ./check nvmeof-mp/
 use_siw=1 ./check srp/
 ```
 
+### Normal user
+
+To run test cases which require normal user privilege, prepare a user and
+specify it to the `NORMAL_USER` variable. The test cases are skipped unless a
+valid user is specified.
+
+```sh
+NORMAL_USER=blktests_user
+```
+
 ### Custom Setup
 
 The `config` file is really just a bash file that is sourced at the beginning
diff --git a/check b/check
index 34e96c4..8eaf5c6 100755
--- a/check
+++ b/check
@@ -799,6 +799,7 @@ fi
 
 : "${LOGGER_PROG:="$(type -P logger || echo true)"}"
 : "${RUN_ZONED_TESTS:=0}"
+: "${NORMAL_USER:=''}"
 
 # Sanity check options.
 if [[ $QUICK_RUN -ne 0 && ! "${TIMEOUT:-}" ]]; then
diff --git a/common/rc b/common/rc
index ef23ebe..af4c0b1 100644
--- a/common/rc
+++ b/common/rc
@@ -381,6 +381,14 @@ _require_test_dev_is_partition() {
 	return 0
 }
 
+_require_normal_user() {
+	if ! id "$NORMAL_USER" >/dev/null 2>&1; then
+		SKIP_REASONS+=("valid NORMAL_USER is not specfied")
+		return 1
+	fi
+	return 0
+}
+
 # Prints a space-separated list with the names of all I/O schedulers supported
 # by block device $1.
 _io_schedulers() {
@@ -409,3 +417,8 @@ _have_writeable_kmsg() {
 	fi
 	return 0
 }
+
+# Run the given command as NORMAL_USER
+_run_user() {
+	su "$NORMAL_USER" -c "$1"
+}
-- 
2.38.1