[LTP] [PATCH v3] lib: new tst_test field to save and restore proc|sys
Jan Stancek
jstancek@redhat.com
Mon Nov 5 09:00:02 CET 2018
To avoid adding specially crafted functions for every feature
where we need to save/restore some proc/sys config, this patch
introduces a new field to tst_test struct where user specifies
NULL terminated array of strings whose values should be saved
before test and restored after.
Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
Changes in v3:
- make list single linked
- drop list parameter, all functions use one single list
doc/test-writing-guidelines.txt | 37 +++++++++++++++
include/tst_sys_conf.h | 21 +++++++++
include/tst_test.h | 7 +++
lib/newlib_tests/.gitignore | 1 +
lib/newlib_tests/test19.c | 48 +++++++++++++++++++
lib/tst_sys_conf.c | 100 ++++++++++++++++++++++++++++++++++++++++
lib/tst_test.c | 13 ++++++
7 files changed, 227 insertions(+)
create mode 100644 include/tst_sys_conf.h
create mode 100644 lib/newlib_tests/test19.c
create mode 100644 lib/tst_sys_conf.c
diff --git a/doc/test-writing-guidelines.txt b/doc/test-writing-guidelines.txt
index f590896472d1..d0b91c36294c 100644
--- a/doc/test-writing-guidelines.txt
+++ b/doc/test-writing-guidelines.txt
@@ -1468,6 +1468,43 @@ first missing driver.
Since it relies on modprobe command, the check will be skipped if the command
itself is not available on the system.
+2.2.27 Saving & restoring /proc|sys values
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+LTP library can be instructed to save and restore value of specified
+(/proc|sys) files. This is achieved by initialized tst_test struct
+field 'save_restore'. It is a NULL terminated array of strings where
+each string represents a file, whose value is saved at the beginning
+and restored at the end of the test. Only first line of a specified
+file is saved and restored.
+
+Pathnames can be optionally prefixed to specify how strictly (during
+'store') are handled files that don't exist:
+ (no prefix) - test ends with TCONF
+ '?' - test prints info message and continues
+ '!' - test ends with TBROK
+
+'restore' is always strict and will TWARN if it encounters any error.
+
+Example:
+
+static const char *save_restore[] = {
+ "/proc/sys/kernel/core_pattern",
+ NULL,
+};
+
+static void setup(void)
+{
+ FILE_PRINTF("/proc/sys/kernel/core_pattern", "/mypath");
+}
+
+static struct tst_test test = {
+ ...
+ .setup = setup,
+ .save_restore = save_restore,
+};
+
+
2.3 Writing a testcase in shell
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/include/tst_sys_conf.h b/include/tst_sys_conf.h
new file mode 100644
index 000000000000..784a94dbe37c
--- /dev/null
+++ b/include/tst_sys_conf.h
@@ -0,0 +1,21 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * Copyright (c) 2018 Jan Stancek <jstancek@redhat.com>
+ */
+
+#ifndef TST_SYS_CONF_H__
+#define TST_SYS_CONF_H__
+
+struct tst_sys_conf {
+ char path[PATH_MAX];
+ char value[PATH_MAX];
+ struct tst_sys_conf *next;
+};
+
+int tst_sys_conf_save_str(const char *path, const char *value);
+int tst_sys_conf_save(const char *path);
+void tst_sys_conf_restore(int verbose);
+void tst_sys_conf_dump(void);
+
+#endif
diff --git a/include/tst_test.h b/include/tst_test.h
index 080b0171d5f2..2ebf746eb720 100644
--- a/include/tst_test.h
+++ b/include/tst_test.h
@@ -42,6 +42,7 @@
#include "tst_minmax.h"
#include "tst_get_bad_addr.h"
#include "tst_path_has_mnt_flags.h"
+#include "tst_sys_conf.h"
/*
* Reports testcase result.
@@ -175,6 +176,12 @@ struct tst_test {
/* NULL terminated array of needed kernel drivers */
const char * const *needs_drivers;
+
+ /*
+ * NULL terminated array of (/proc, /sys) files to save
+ * before setup and restore after cleanup
+ */
+ const char * const *save_restore;
};
/*
diff --git a/lib/newlib_tests/.gitignore b/lib/newlib_tests/.gitignore
index 76e89e438f55..c702644f0d1c 100644
--- a/lib/newlib_tests/.gitignore
+++ b/lib/newlib_tests/.gitignore
@@ -20,6 +20,7 @@ tst_res_hexd
tst_strstatus
test17
test18
+test19
tst_expiration_timer
test_exec
test_exec_child
diff --git a/lib/newlib_tests/test19.c b/lib/newlib_tests/test19.c
new file mode 100644
index 000000000000..37fc8e9e0227
--- /dev/null
+++ b/lib/newlib_tests/test19.c
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2018, Linux Test Project
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <unistd.h>
+#include "tst_test.h"
+#include "tst_sys_conf.h"
+
+static char orig[1024];
+
+static const char * const save_restore[] = {
+ "?/proc/nonexistent",
+ "!/proc/sys/kernel/numa_balancing",
+ "/proc/sys/kernel/core_pattern",
+ NULL,
+};
+
+static void setup(void)
+{
+ SAFE_FILE_SCANF("/proc/sys/kernel/core_pattern", "%s", orig);
+ SAFE_FILE_PRINTF("/proc/sys/kernel/core_pattern", "changed");
+}
+
+static void run(void)
+{
+ tst_res(TPASS, "OK");
+}
+
+static struct tst_test test = {
+ .needs_root = 1,
+ .test_all = run,
+ .setup = setup,
+ .save_restore = save_restore,
+};
diff --git a/lib/tst_sys_conf.c b/lib/tst_sys_conf.c
new file mode 100644
index 000000000000..893ef9d5c74b
--- /dev/null
+++ b/lib/tst_sys_conf.c
@@ -0,0 +1,100 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * Copyright (c) 2018 Jan Stancek <jstancek@redhat.com>
+ */
+
+#include <limits.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#define TST_NO_DEFAULT_MAIN
+#include "tst_test.h"
+#include "tst_sys_conf.h"
+
+static struct tst_sys_conf save_restore_data;
+
+void tst_sys_conf_dump(void)
+{
+ struct tst_sys_conf *i = save_restore_data.next;
+
+ while (i) {
+ tst_res(TINFO, "%s -> %s", i->path, i->value);
+ i = i->next;
+ }
+}
+
+int tst_sys_conf_save_str(const char *path, const char *value)
+{
+ struct tst_sys_conf *n = SAFE_MALLOC(sizeof(*n));
+
+ strncpy(n->path, path, sizeof(n->path));
+ strncpy(n->value, value, sizeof(n->value));
+
+ /* add new entry at the beginning, right after 'c' */
+ n->next = save_restore_data.next;
+ save_restore_data.next = n;
+
+ return 0;
+}
+
+int tst_sys_conf_save(const char *path)
+{
+ char line[PATH_MAX];
+ FILE *fp;
+ void *ret;
+ char flag;
+
+ if (!path)
+ tst_brk(TBROK, "path is empty");
+
+ flag = path[0];
+ if (flag == '?' || flag == '!')
+ path++;
+
+ if (access(path, F_OK) != 0) {
+ switch (flag) {
+ case '?':
+ tst_res(TINFO, "Path not found: '%s'", path);
+ break;
+ case '!':
+ tst_brk(TBROK|TERRNO, "Path not found: '%s'", path);
+ break;
+ default:
+ tst_brk(TCONF|TERRNO, "Path not found: '%s'", path);
+ }
+ return 1;
+ }
+
+ fp = fopen(path, "r");
+ if (fp == NULL) {
+ tst_brk(TBROK | TERRNO, "Failed to open FILE '%s' for reading",
+ path);
+ return 1;
+ }
+
+ ret = fgets(line, sizeof(line), fp);
+ fclose(fp);
+
+ if (ret == NULL) {
+ tst_brk(TBROK | TERRNO, "Failed to read anything from '%s'",
+ path);
+ }
+
+ return tst_sys_conf_save_str(path, line);
+}
+
+void tst_sys_conf_restore(int verbose)
+{
+ struct tst_sys_conf *i = save_restore_data.next;
+
+ while (i) {
+ if (verbose) {
+ tst_res(TINFO, "Restoring conf.: %s -> %s\n",
+ i->path, i->value);
+ }
+ FILE_PRINTF(i->path, "%s", i->value);
+ i = i->next;
+ }
+}
+
diff --git a/lib/tst_test.c b/lib/tst_test.c
index 117e61462d30..661fbbfce003 100644
--- a/lib/tst_test.c
+++ b/lib/tst_test.c
@@ -35,6 +35,7 @@
#include "tst_timer_test.h"
#include "tst_clocks.h"
#include "tst_timer.h"
+#include "tst_sys_conf.h"
#include "old_resource.h"
#include "old_device.h"
@@ -809,6 +810,15 @@ static void do_setup(int argc, char *argv[])
if (needs_tmpdir() && !tst_tmpdir_created())
tst_tmpdir();
+ if (tst_test->save_restore) {
+ const char * const *name = tst_test->save_restore;
+
+ while (*name) {
+ tst_sys_conf_save(*name);
+ name++;
+ }
+ }
+
if (tst_test->mntpoint)
SAFE_MKDIR(tst_test->mntpoint, 0777);
@@ -885,6 +895,9 @@ static void do_cleanup(void)
tst_rmdir();
}
+ if (tst_test->save_restore)
+ tst_sys_conf_restore(0);
+
cleanup_ipc();
}
--
1.8.3.1
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