[LTP] [PATCH v2] power_management: rewrite runpwtests04.sh in C

[LTP] [PATCH v2] power_management: rewrite runpwtests04.sh in C

[Jinseok Kim]

As part of the ongoing effort to reduce shell-based tests in LTP,
rewrite the cpuidle sysfs smoke test in C using the modern LTP test API.

The new implementation preserves the original test semantics while
removing shell dependencies.

Signed-off-by: Jinseok Kim <always.starving0@gmail.com>
---
Changes in v2:
- Update runtest entry
- Clarify commit message
- Link to v1 : https://lore.kernel.org/ltp/20260516200015.12689-1-always.starving0@gmail.com
---
 runtest/power_management_tests                |  2 +-
 testcases/kernel/power_management/.gitignore  |  1 +
 testcases/kernel/power_management/pwtests01.c | 52 +++++++++++++++++
 .../kernel/power_management/runpwtests04.sh   | 58 -------------------
 4 files changed, 54 insertions(+), 59 deletions(-)
 create mode 100644 testcases/kernel/power_management/.gitignore
 create mode 100644 testcases/kernel/power_management/pwtests01.c
 delete mode 100755 testcases/kernel/power_management/runpwtests04.sh

diff --git a/runtest/power_management_tests b/runtest/power_management_tests
index b670da6ec..4246a16d4 100644
--- a/runtest/power_management_tests
+++ b/runtest/power_management_tests
@@ -1,4 +1,4 @@
 #POWER_MANAGEMENT
+pwtests01 pwtests01
 runpwtests03 runpwtests03.sh
-runpwtests04 runpwtests04.sh
 runpwtests06 runpwtests06.sh
diff --git a/testcases/kernel/power_management/.gitignore b/testcases/kernel/power_management/.gitignore
new file mode 100644
index 000000000..33a901350
--- /dev/null
+++ b/testcases/kernel/power_management/.gitignore
@@ -0,0 +1 @@
+/pwtests01
diff --git a/testcases/kernel/power_management/pwtests01.c b/testcases/kernel/power_management/pwtests01.c
new file mode 100644
index 000000000..90d05ee05
--- /dev/null
+++ b/testcases/kernel/power_management/pwtests01.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 Jinseok Kim <always.starving0@gmail.com>
+ */
+
+/*\
+ * Basic cpuidle sysfs smoke test.
+ *
+ * Verify that selected cpuidle sysfs files are readable.
+ */
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "tst_test.h"
+
+#define CPUIDLE_PATH "/sys/devices/system/cpu/cpuidle"
+
+static struct tcases {
+	const char *name;
+} tcases[] = {
+	{ "current_governor_ro" },
+	{ "current_driver" },
+};
+
+static void verify_cpuidle(unsigned int i)
+{
+	int fd;
+	char path[PATH_MAX];
+	char buf[32];
+
+	snprintf(path, sizeof(path), "%s/%s", CPUIDLE_PATH, tcases[i].name);
+
+	fd = SAFE_OPEN(path, O_RDONLY);
+
+	SAFE_READ(0, fd, buf, sizeof(buf));
+	SAFE_CLOSE(fd);
+
+	tst_res(TPASS, "%s read successfully", path);
+}
+
+static void setup(void)
+{
+	if (access(CPUIDLE_PATH, R_OK))
+		tst_brk(TCONF, "%s is not available", CPUIDLE_PATH);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.tcnt = ARRAY_SIZE(tcases),
+	.test = verify_cpuidle,
+};
diff --git a/testcases/kernel/power_management/runpwtests04.sh b/testcases/kernel/power_management/runpwtests04.sh
deleted file mode 100755
index 6565320d2..000000000
--- a/testcases/kernel/power_management/runpwtests04.sh
+++ /dev/null
@@ -1,58 +0,0 @@
-#! /bin/sh
-#
-# Copyright (c) International Business Machines  Corp., 2001
-# Author: Nageswara R Sastry <nasastry@in.ibm.com>
-#
-# This program is free software;  you can redistribute it and#or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful, but
-# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
-# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
-# for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program;  if not, write to the Free Software Foundation,
-# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
-#
-
-export TCID="Power_Management04"
-export TST_TOTAL=1
-
-. test.sh
-. pm_include.sh
-
-check_cpuidle_sysfs_files() {
-	RC=0
-	if [ -d /sys/devices/system/cpu/cpuidle ] ; then
-		for files in current_governor_ro current_driver
-		do
-			cat /sys/devices/system/cpu/cpuidle/${files} \
-				>/dev/null 2>&1
-			if [ $? -ne 0 ] ; then
-				echo "${0}: FAIL: cat ${files}"
-				RC=1
-			fi
-		done
-	fi
-	if [ ${RC} -eq 0 ] ; then
-		echo "${0}: PASS: Checking cpu idle sysfs files"
-	else
-		echo "${0}: FAIL: Checking cpu idle sysfs files"
-	fi
-	return $RC
-}
-
-# Checking test environment
-check_arch
-
-# Checking cpuidle sysfs interface files
-if check_cpuidle_sysfs_files ; then
-	tst_resm TPASS "CPUIDLE sysfs tests passed"
-else
-    tst_resm TFAIL "CPUIDLE sysfs tests failed"
-fi
-
-tst_exit
--
2.43.0

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Re: [LTP] power_management: rewrite runpwtests04.sh in C

[linuxtestproject.agent]

Hi Jinseok,

On Mon, 25 May 2026 00:42:20 +0900, Jinseok Kim wrote:
> power_management: rewrite runpwtests04.sh in C

[...]

> +static void verify_cpuidle(unsigned int i)
> +{
> +	int fd;
> +	char path[PATH_MAX];
> +	char buf[32];
> +
> +	snprintf(path, sizeof(path), "%s/%s", CPUIDLE_PATH, tcases[i].name);
> +
> +	fd = SAFE_OPEN(path, O_RDONLY);

SAFE_OPEN() on a non-existent file aborts the test with TBROK.  The
files `current_governor_ro` and `current_driver` may not exist on every
system that has a cpuidle directory (e.g. no cpuidle driver loaded, or
kernel lacks CONFIG_CPU_IDLE_GOV_*).  Use open() directly and convert
ENOENT to TCONF:

    fd = open(path, O_RDONLY);
    if (fd < 0) {
        if (errno == ENOENT)
            tst_res(TCONF, "%s not available", path);
        else
            tst_res(TFAIL | TERRNO, "open(%s) failed", path);
        return;
    }

> +static struct tcases {
> +	const char *name;
> +} tcases[] = {

Tag and variable share the same name.  LTP convention uses the singular
for the struct tag: `struct tcase { ... } tcases[] = {`.

[...]

The new test is named `pwtests01` while the shell test it replaces was
`runpwtests04`.  The commit message does not explain the rename.  If
`pwtests01` is intentional (e.g. start of a new naming series), please
document it briefly.

---
Note:

Our agent completed the review of the patch. The full review can be
found at: https://github.com/linux-test-project/ltp/actions

The agent can sometimes produce false positives although often its
findings are genuine. If you find issues with the review, please
comment this email or ignore the suggestions.

Regards,
LTP AI Reviewer

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] power_management: rewrite runpwtests04.sh in C

[linuxtestproject.agent]

Hi Jinseok,

On Mon, May 25, 2026, Jinseok Kim wrote:
> power_management: rewrite runpwtests04.sh in C

> +static void verify_cpuidle(unsigned int i)
> +{
> +	int fd;
> +	char path[PATH_MAX];
> +	char buf[32];
> +
> +	snprintf(path, sizeof(path), "%s/%s", CPUIDLE_PATH, tcases[i].name);
> +
> +	fd = SAFE_OPEN(path, O_RDONLY);
> +
> +	SAFE_READ(0, fd, buf, sizeof(buf));
> +	SAFE_CLOSE(fd);

If SAFE_READ() triggers tst_brk(), execution jumps to cleanup but
there is no cleanup registered, so fd is never closed.

The LTP convention is to track file descriptors in a static variable
initialized to -1 and close them in a .cleanup handler:

  static int fd = -1;

  static void verify_cpuidle(unsigned int i)
  {
          ...
          fd = SAFE_OPEN(path, O_RDONLY);
          SAFE_READ(0, fd, buf, sizeof(buf));
          SAFE_CLOSE(fd);

          tst_res(TPASS, "%s read successfully", path);
  }

  static void cleanup(void)
  {
          if (fd != -1)
                  SAFE_CLOSE(fd);
  }

  static struct tst_test test = {
          .setup = setup,
          .cleanup = cleanup,
          ...
  };

Verdict: Needs revision

---
Note:

The agent can sometimes produce false positives although often its
findings are genuine. If you find issues with the review, please
comment this email or ignore the suggestions.

Regards,
LTP AI Reviewer

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Re: [LTP] [PATCH v2] power_management: rewrite runpwtests04.sh in C

[Andrea Cervesato via ltp]

Hi Jinseok,

thanks for rewriting the test into C API.
The test LGTM, but indeed we should release the file descriptor
at cleanup level. Please send v3 with this and I will merge the
test.

Regards,
--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com

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Re: [LTP] [PATCH v2] power_management: rewrite runpwtests04.sh in C

[Andrea Cervesato via ltp]

Hi Jinseok,

for some reasons I didn't receive your [3] in my ML, but I have
the CI results and the patch-set needs to be fixed because it
doesn't apply:

https://github.com/linux-test-project/ltp/actions/runs/27367707128

Please send v4.

Thanks,
--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com

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