[PATCH v4 0/6] lib/string: Add strscpy_pad() function

[PATCH v4 0/6] lib/string: Add strscpy_pad() function

[tobin]

Hi Shua,

Here is the set with cleanup as suggested by Kees on v3.

Configured, built, and tested all modules loaded by
tools/testing/selftests/lib/*.sh

>From previous cover letters ...

While doing the testing for strscpy_pad() it was noticed that there is
duplication in how test modules are being fed to kselftest and also in
the test modules themselves.

This set makes an attempt at adding a framework to kselftest for writing
kernel test modules.  It also adds a script for use in creating script
test runners for kselftest.  My macro-foo is not great, all criticism
and suggestions very much appreciated.  The design is based on test
modules lib/test_printf.c, lib/test_bitmap.c, lib/test_xarray.c.

Changes since last version:

 - Remove dependency on Bash (thanks Kees)
 - Use oneliner to implement kselftest test runners (thanks Kees)
 - Squash patch that adds kselftest script creator script with patch
   that uses it. 
 - Fix typos (thanks Randy)
 - Add Kees' Acked-by tags to all patches

thanks,
Tobin.


Tobin C. Harding (6):
  lib/test_printf: Add empty module_exit function
  kselftest: Add test runner creation script
  kselftest: Add test module framework header
  lib: Use new kselftest header
  lib/string: Add strscpy_pad() function
  lib: Add test module for strscpy_pad

 Documentation/dev-tools/kselftest.rst        |  94 +++++++++++-
 include/linux/string.h                       |   4 +
 lib/Kconfig.debug                            |   3 +
 lib/Makefile                                 |   1 +
 lib/string.c                                 |  47 +++++-
 lib/test_bitmap.c                            |  20 +--
 lib/test_printf.c                            |  17 +--
 lib/test_strscpy.c                           | 150 +++++++++++++++++++
 tools/testing/selftests/kselftest_module.h   |  48 ++++++
 tools/testing/selftests/kselftest_module.sh  |  84 +++++++++++
 tools/testing/selftests/lib/Makefile         |   2 +-
 tools/testing/selftests/lib/bitmap.sh        |  18 +--
 tools/testing/selftests/lib/config           |   1 +
 tools/testing/selftests/lib/prime_numbers.sh |  17 +--
 tools/testing/selftests/lib/printf.sh        |  19 +--
 tools/testing/selftests/lib/strscpy.sh       |   3 +
 16 files changed, 440 insertions(+), 88 deletions(-)
 create mode 100644 lib/test_strscpy.c
 create mode 100644 tools/testing/selftests/kselftest_module.h
 create mode 100755 tools/testing/selftests/kselftest_module.sh
 create mode 100755 tools/testing/selftests/lib/strscpy.sh

-- 
2.21.0

[PATCH v4 0/6] lib/string: Add strscpy_pad() function

[Tobin C. Harding]

Hi Shua,

Here is the set with cleanup as suggested by Kees on v3.

Configured, built, and tested all modules loaded by
tools/testing/selftests/lib/*.sh

>From previous cover letters ...

While doing the testing for strscpy_pad() it was noticed that there is
duplication in how test modules are being fed to kselftest and also in
the test modules themselves.

This set makes an attempt at adding a framework to kselftest for writing
kernel test modules.  It also adds a script for use in creating script
test runners for kselftest.  My macro-foo is not great, all criticism
and suggestions very much appreciated.  The design is based on test
modules lib/test_printf.c, lib/test_bitmap.c, lib/test_xarray.c.

Changes since last version:

 - Remove dependency on Bash (thanks Kees)
 - Use oneliner to implement kselftest test runners (thanks Kees)
 - Squash patch that adds kselftest script creator script with patch
   that uses it. 
 - Fix typos (thanks Randy)
 - Add Kees' Acked-by tags to all patches

thanks,
Tobin.


Tobin C. Harding (6):
  lib/test_printf: Add empty module_exit function
  kselftest: Add test runner creation script
  kselftest: Add test module framework header
  lib: Use new kselftest header
  lib/string: Add strscpy_pad() function
  lib: Add test module for strscpy_pad

 Documentation/dev-tools/kselftest.rst        |  94 +++++++++++-
 include/linux/string.h                       |   4 +
 lib/Kconfig.debug                            |   3 +
 lib/Makefile                                 |   1 +
 lib/string.c                                 |  47 +++++-
 lib/test_bitmap.c                            |  20 +--
 lib/test_printf.c                            |  17 +--
 lib/test_strscpy.c                           | 150 +++++++++++++++++++
 tools/testing/selftests/kselftest_module.h   |  48 ++++++
 tools/testing/selftests/kselftest_module.sh  |  84 +++++++++++
 tools/testing/selftests/lib/Makefile         |   2 +-
 tools/testing/selftests/lib/bitmap.sh        |  18 +--
 tools/testing/selftests/lib/config           |   1 +
 tools/testing/selftests/lib/prime_numbers.sh |  17 +--
 tools/testing/selftests/lib/printf.sh        |  19 +--
 tools/testing/selftests/lib/strscpy.sh       |   3 +
 16 files changed, 440 insertions(+), 88 deletions(-)
 create mode 100644 lib/test_strscpy.c
 create mode 100644 tools/testing/selftests/kselftest_module.h
 create mode 100755 tools/testing/selftests/kselftest_module.sh
 create mode 100755 tools/testing/selftests/lib/strscpy.sh

-- 
2.21.0

[PATCH v4 1/6] lib/test_printf: Add empty module_exit function

[tobin]

Currently the test_printf module does not have an exit function, this
prevents the module from being unloaded.  If we cannot unload the
module we cannot run the tests a second time.

Add an empty exit function.

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 lib/test_printf.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/test_printf.c b/lib/test_printf.c
index 659b6cc0d483..601e8519319a 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -615,5 +615,11 @@ test_printf_init(void)
 
 module_init(test_printf_init);
 
+static void __exit test_printf_exit(void)
+{
+}
+
+module_exit(test_printf_exit);
+
 MODULE_AUTHOR("Rasmus Villemoes <linux at rasmusvillemoes.dk>");
 MODULE_LICENSE("GPL");
-- 
2.21.0

[PATCH v4 1/6] lib/test_printf: Add empty module_exit function

[Tobin C. Harding]

Currently the test_printf module does not have an exit function, this
prevents the module from being unloaded.  If we cannot unload the
module we cannot run the tests a second time.

Add an empty exit function.

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 lib/test_printf.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/test_printf.c b/lib/test_printf.c
index 659b6cc0d483..601e8519319a 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -615,5 +615,11 @@ test_printf_init(void)
 
 module_init(test_printf_init);
 
+static void __exit test_printf_exit(void)
+{
+}
+
+module_exit(test_printf_exit);
+
 MODULE_AUTHOR("Rasmus Villemoes <linux at rasmusvillemoes.dk>");
 MODULE_LICENSE("GPL");
-- 
2.21.0

[PATCH v4 2/6] kselftest: Add test runner creation script

[tobin]

Currently if we wish to use kselftest to run tests within a kernel
module we write a small script to load/unload and do error reporting.
There are a bunch of these under tools/testing/selftests/lib/ that are
all identical except for the test name.  We can reduce code duplication
and improve maintainability if we have one version of this.  However
kselftest requires an executable for each test.  We can move all the
script logic to a central script then have each individual test script
call the main script.

Oneliner to call kselftest_module.sh courtesy of Kees, thanks!

Add test runner creation script.  Convert
tools/testing/selftests/lib/*.sh to use new test creation script.

Testing
-------

Configure kselftests for lib/ then build and boot kernel.  Then run
kselftests as follows:

  $ cd /path/to/kernel/tree
  $ sudo make O=$output_path -C tools/testing/selftests TARGETS="lib" run_tests

and also

  $ cd /path/to/kernel/tree
  $ cd tools/testing/selftests
  $ sudo make O=$output_path TARGETS="lib" run_tests

and also

  $ cd /path/to/kernel/tree
  $ cd tools/testing/selftests
  $ sudo make TARGETS="lib" run_tests

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 tools/testing/selftests/kselftest_module.sh  | 84 ++++++++++++++++++++
 tools/testing/selftests/lib/bitmap.sh        | 18 +----
 tools/testing/selftests/lib/prime_numbers.sh | 17 +---
 tools/testing/selftests/lib/printf.sh        | 19 +----
 4 files changed, 88 insertions(+), 50 deletions(-)
 create mode 100755 tools/testing/selftests/kselftest_module.sh

diff --git a/tools/testing/selftests/kselftest_module.sh b/tools/testing/selftests/kselftest_module.sh
new file mode 100755
index 000000000000..18e1c7992d30
--- /dev/null
+++ b/tools/testing/selftests/kselftest_module.sh
@@ -0,0 +1,84 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+
+#
+# Runs an individual test module.
+#
+# kselftest expects a separate executable for each test, this can be
+# created by adding a script like this:
+#
+#   #!/bin/sh
+#   SPDX-License-Identifier: GPL-2.0+
+#   $(dirname $0)/../kselftest_module.sh "description" module_name
+#
+# Example: tools/testing/selftests/lib/printf.sh
+
+desc=""				# Output prefix.
+module=""			# Filename (without the .ko).
+args=""				# modprobe arguments.
+
+modprobe="/sbin/modprobe"
+
+main() {
+    parse_args "$@"
+    assert_root
+    assert_have_module
+    run_module
+}
+
+parse_args() {
+    script=${0##*/}
+
+    if [ $# -lt 2 ]; then
+	echo "Usage: $script <description> <module_name> [FAIL]"
+	exit 1
+    fi
+
+    desc="$1"
+    shift || true
+    module="$1"
+    shift || true
+    args="$@"
+}
+
+assert_root() {
+    if [ ! -w /dev ]; then
+	skip "please run as root"
+    fi
+}
+
+assert_have_module() {
+    if ! $modprobe -q -n $module; then
+	skip "module $module is not found"
+    fi
+}
+
+run_module() {
+    if $modprobe -q $module $args; then
+	$modprobe -q -r $module
+	say "ok"
+    else
+	fail ""
+    fi
+}
+
+say() {
+    echo "$desc: $1"
+}
+
+
+fail() {
+    say "$1 [FAIL]" >&2
+    exit 1
+}
+
+skip() {
+    say "$1 [SKIP]" >&2
+    # Kselftest framework requirement - SKIP code is 4.
+    exit 4
+}
+
+#
+# Main script
+#
+main "$@"
diff --git a/tools/testing/selftests/lib/bitmap.sh b/tools/testing/selftests/lib/bitmap.sh
index 5a90006d1aea..5511dddc5c2d 100755
--- a/tools/testing/selftests/lib/bitmap.sh
+++ b/tools/testing/selftests/lib/bitmap.sh
@@ -1,19 +1,3 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
-
-# Kselftest framework requirement - SKIP code is 4.
-ksft_skip=4
-
-# Runs bitmap infrastructure tests using test_bitmap kernel module
-if ! /sbin/modprobe -q -n test_bitmap; then
-	echo "bitmap: module test_bitmap is not found [SKIP]"
-	exit $ksft_skip
-fi
-
-if /sbin/modprobe -q test_bitmap; then
-	/sbin/modprobe -q -r test_bitmap
-	echo "bitmap: ok"
-else
-	echo "bitmap: [FAIL]"
-	exit 1
-fi
+$(dirname $0)/../kselftest_module.sh "bitmap" test_bitmap
diff --git a/tools/testing/selftests/lib/prime_numbers.sh b/tools/testing/selftests/lib/prime_numbers.sh
index 78e7483c8d60..43b28f24e453 100755
--- a/tools/testing/selftests/lib/prime_numbers.sh
+++ b/tools/testing/selftests/lib/prime_numbers.sh
@@ -1,19 +1,4 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 # Checks fast/slow prime_number generation for inconsistencies
-
-# Kselftest framework requirement - SKIP code is 4.
-ksft_skip=4
-
-if ! /sbin/modprobe -q -n prime_numbers; then
-	echo "prime_numbers: module prime_numbers is not found [SKIP]"
-	exit $ksft_skip
-fi
-
-if /sbin/modprobe -q prime_numbers selftest=65536; then
-	/sbin/modprobe -q -r prime_numbers
-	echo "prime_numbers: ok"
-else
-	echo "prime_numbers: [FAIL]"
-	exit 1
-fi
+$(dirname $0)/../kselftest_module.sh "prime numbers" prime_numbers selftest=65536
diff --git a/tools/testing/selftests/lib/printf.sh b/tools/testing/selftests/lib/printf.sh
index 45a23e2d64ad..2ffa61da0296 100755
--- a/tools/testing/selftests/lib/printf.sh
+++ b/tools/testing/selftests/lib/printf.sh
@@ -1,19 +1,4 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
-# Runs printf infrastructure using test_printf kernel module
-
-# Kselftest framework requirement - SKIP code is 4.
-ksft_skip=4
-
-if ! /sbin/modprobe -q -n test_printf; then
-	echo "printf: module test_printf is not found [SKIP]"
-	exit $ksft_skip
-fi
-
-if /sbin/modprobe -q test_printf; then
-	/sbin/modprobe -q -r test_printf
-	echo "printf: ok"
-else
-	echo "printf: [FAIL]"
-	exit 1
-fi
+# Tests the printf infrastructure using test_printf kernel module.
+$(dirname $0)/../kselftest_module.sh "printf" test_printf
-- 
2.21.0

[PATCH v4 2/6] kselftest: Add test runner creation script

[Tobin C. Harding]

Currently if we wish to use kselftest to run tests within a kernel
module we write a small script to load/unload and do error reporting.
There are a bunch of these under tools/testing/selftests/lib/ that are
all identical except for the test name.  We can reduce code duplication
and improve maintainability if we have one version of this.  However
kselftest requires an executable for each test.  We can move all the
script logic to a central script then have each individual test script
call the main script.

Oneliner to call kselftest_module.sh courtesy of Kees, thanks!

Add test runner creation script.  Convert
tools/testing/selftests/lib/*.sh to use new test creation script.

Testing
-------

Configure kselftests for lib/ then build and boot kernel.  Then run
kselftests as follows:

  $ cd /path/to/kernel/tree
  $ sudo make O=$output_path -C tools/testing/selftests TARGETS="lib" run_tests

and also

  $ cd /path/to/kernel/tree
  $ cd tools/testing/selftests
  $ sudo make O=$output_path TARGETS="lib" run_tests

and also

  $ cd /path/to/kernel/tree
  $ cd tools/testing/selftests
  $ sudo make TARGETS="lib" run_tests

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 tools/testing/selftests/kselftest_module.sh  | 84 ++++++++++++++++++++
 tools/testing/selftests/lib/bitmap.sh        | 18 +----
 tools/testing/selftests/lib/prime_numbers.sh | 17 +---
 tools/testing/selftests/lib/printf.sh        | 19 +----
 4 files changed, 88 insertions(+), 50 deletions(-)
 create mode 100755 tools/testing/selftests/kselftest_module.sh

diff --git a/tools/testing/selftests/kselftest_module.sh b/tools/testing/selftests/kselftest_module.sh
new file mode 100755
index 000000000000..18e1c7992d30
--- /dev/null
+++ b/tools/testing/selftests/kselftest_module.sh
@@ -0,0 +1,84 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+
+#
+# Runs an individual test module.
+#
+# kselftest expects a separate executable for each test, this can be
+# created by adding a script like this:
+#
+#   #!/bin/sh
+#   SPDX-License-Identifier: GPL-2.0+
+#   $(dirname $0)/../kselftest_module.sh "description" module_name
+#
+# Example: tools/testing/selftests/lib/printf.sh
+
+desc=""				# Output prefix.
+module=""			# Filename (without the .ko).
+args=""				# modprobe arguments.
+
+modprobe="/sbin/modprobe"
+
+main() {
+    parse_args "$@"
+    assert_root
+    assert_have_module
+    run_module
+}
+
+parse_args() {
+    script=${0##*/}
+
+    if [ $# -lt 2 ]; then
+	echo "Usage: $script <description> <module_name> [FAIL]"
+	exit 1
+    fi
+
+    desc="$1"
+    shift || true
+    module="$1"
+    shift || true
+    args="$@"
+}
+
+assert_root() {
+    if [ ! -w /dev ]; then
+	skip "please run as root"
+    fi
+}
+
+assert_have_module() {
+    if ! $modprobe -q -n $module; then
+	skip "module $module is not found"
+    fi
+}
+
+run_module() {
+    if $modprobe -q $module $args; then
+	$modprobe -q -r $module
+	say "ok"
+    else
+	fail ""
+    fi
+}
+
+say() {
+    echo "$desc: $1"
+}
+
+
+fail() {
+    say "$1 [FAIL]" >&2
+    exit 1
+}
+
+skip() {
+    say "$1 [SKIP]" >&2
+    # Kselftest framework requirement - SKIP code is 4.
+    exit 4
+}
+
+#
+# Main script
+#
+main "$@"
diff --git a/tools/testing/selftests/lib/bitmap.sh b/tools/testing/selftests/lib/bitmap.sh
index 5a90006d1aea..5511dddc5c2d 100755
--- a/tools/testing/selftests/lib/bitmap.sh
+++ b/tools/testing/selftests/lib/bitmap.sh
@@ -1,19 +1,3 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
-
-# Kselftest framework requirement - SKIP code is 4.
-ksft_skip=4
-
-# Runs bitmap infrastructure tests using test_bitmap kernel module
-if ! /sbin/modprobe -q -n test_bitmap; then
-	echo "bitmap: module test_bitmap is not found [SKIP]"
-	exit $ksft_skip
-fi
-
-if /sbin/modprobe -q test_bitmap; then
-	/sbin/modprobe -q -r test_bitmap
-	echo "bitmap: ok"
-else
-	echo "bitmap: [FAIL]"
-	exit 1
-fi
+$(dirname $0)/../kselftest_module.sh "bitmap" test_bitmap
diff --git a/tools/testing/selftests/lib/prime_numbers.sh b/tools/testing/selftests/lib/prime_numbers.sh
index 78e7483c8d60..43b28f24e453 100755
--- a/tools/testing/selftests/lib/prime_numbers.sh
+++ b/tools/testing/selftests/lib/prime_numbers.sh
@@ -1,19 +1,4 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 # Checks fast/slow prime_number generation for inconsistencies
-
-# Kselftest framework requirement - SKIP code is 4.
-ksft_skip=4
-
-if ! /sbin/modprobe -q -n prime_numbers; then
-	echo "prime_numbers: module prime_numbers is not found [SKIP]"
-	exit $ksft_skip
-fi
-
-if /sbin/modprobe -q prime_numbers selftest=65536; then
-	/sbin/modprobe -q -r prime_numbers
-	echo "prime_numbers: ok"
-else
-	echo "prime_numbers: [FAIL]"
-	exit 1
-fi
+$(dirname $0)/../kselftest_module.sh "prime numbers" prime_numbers selftest=65536
diff --git a/tools/testing/selftests/lib/printf.sh b/tools/testing/selftests/lib/printf.sh
index 45a23e2d64ad..2ffa61da0296 100755
--- a/tools/testing/selftests/lib/printf.sh
+++ b/tools/testing/selftests/lib/printf.sh
@@ -1,19 +1,4 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
-# Runs printf infrastructure using test_printf kernel module
-
-# Kselftest framework requirement - SKIP code is 4.
-ksft_skip=4
-
-if ! /sbin/modprobe -q -n test_printf; then
-	echo "printf: module test_printf is not found [SKIP]"
-	exit $ksft_skip
-fi
-
-if /sbin/modprobe -q test_printf; then
-	/sbin/modprobe -q -r test_printf
-	echo "printf: ok"
-else
-	echo "printf: [FAIL]"
-	exit 1
-fi
+# Tests the printf infrastructure using test_printf kernel module.
+$(dirname $0)/../kselftest_module.sh "printf" test_printf
-- 
2.21.0

[PATCH v4 3/6] kselftest: Add test module framework header

[tobin]

kselftest runs as a userspace process.  Sometimes we need to test things
from kernel space.  One way of doing this is by creating a test module.
Currently doing so requires developers to write a bunch of boiler plate
in the module if kselftest is to be used to run the tests.  This means
we currently have a load of duplicate code to achieve these ends.  If we
have a uniform method for implementing test modules then we can reduce
code duplication, ensure uniformity in the test framework, ease code
maintenance, and reduce the work required to create tests.  This all
helps to encourage developers to write and run tests.

Add a C header file that can be included in test modules.  This provides
a single point for common test functions/macros.  Implement a few macros
that make up the start of the test framework.

Add documentation for new kselftest header to kselftest documentation.

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 Documentation/dev-tools/kselftest.rst      | 94 +++++++++++++++++++++-
 tools/testing/selftests/kselftest_module.h | 48 +++++++++++
 2 files changed, 140 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/kselftest_module.h

diff --git a/Documentation/dev-tools/kselftest.rst b/Documentation/dev-tools/kselftest.rst
index 7756f7a7c23b..c8c03388b9de 100644
--- a/Documentation/dev-tools/kselftest.rst
+++ b/Documentation/dev-tools/kselftest.rst
@@ -14,6 +14,10 @@ in safe mode with a limited scope. In limited mode, cpu-hotplug test is
 run on a single cpu as opposed to all hotplug capable cpus, and memory
 hotplug test is run on 2% of hotplug capable memory instead of 10%.
 
+kselftest runs as a userspace process.  Tests that can be written/run in
+userspace may wish to use the `Test Harness`_.  Tests that need to be
+run in kernel space may wish to use a `Test Module`_.
+
 Running the selftests (hotplug tests are run in limited mode)
 =============================================================
 
@@ -161,11 +165,97 @@ Contributing new tests (details)
 
    e.g: tools/testing/selftests/android/config
 
+Test Module
+===========
+
+Kselftest tests the kernel from userspace.  Sometimes things need
+testing from within the kernel, one method of doing this is to create a
+test module.  We can tie the module into the kselftest framework by
+using a shell script test runner.  ``kselftest_module.sh`` is designed
+to facilitate this process.  There is also a header file provided to
+assist writing kernel modules that are for use with kselftest:
+
+- ``tools/testing/kselftest/kselftest_module.h``
+- ``tools/testing/kselftest/kselftest_module.sh``
+
+How to use
+----------
+
+Here we show the typical steps to create a test module and tie it into
+kselftest.  We use kselftests for lib/ as an example.
+
+1. Create the test module
+
+2. Create the test script that will run (load/unload) the module
+   e.g. ``tools/testing/selftests/lib/printf.sh``
+
+3. Add line to config file e.g. ``tools/testing/selftests/lib/config``
+
+4. Add test script to makefile  e.g. ``tools/testing/selftests/lib/Makefile``
+
+5. Verify it works:
+
+.. code-block:: sh
+
+   # Assumes you have booted a fresh build of this kernel tree
+   cd /path/to/linux/tree
+   make kselftest-merge
+   make modules
+   sudo make modules_install
+   make TARGETS=lib kselftest
+
+Example Module
+--------------
+
+A bare bones test module might look like this:
+
+.. code-block:: c
+
+   // SPDX-License-Identifier: GPL-2.0+
+
+   #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+   #include "../tools/testing/selftests/kselftest_module.h"
+
+   KSTM_MODULE_GLOBALS();
+
+   /*
+    * Kernel module for testing the foobinator
+    */
+
+   static int __init test_function()
+   {
+           ...
+   }
+
+   static void __init selftest(void)
+   {
+           KSTM_CHECK_ZERO(do_test_case("", 0));
+   }
+
+   KSTM_MODULE_LOADERS(test_foo);
+   MODULE_AUTHOR("John Developer <jd at fooman.org>");
+   MODULE_LICENSE("GPL");
+
+Example test script
+-------------------
+
+.. code-block:: sh
+
+    #!/bin/bash
+    # SPDX-License-Identifier: GPL-2.0+
+    $(dirname $0)/../kselftest_module.sh "foo" test_foo
+
+
 Test Harness
 ============
 
-The kselftest_harness.h file contains useful helpers to build tests.  The tests
-from tools/testing/selftests/seccomp/seccomp_bpf.c can be used as example.
+The kselftest_harness.h file contains useful helpers to build tests.  The
+test harness is for userspace testing, for kernel space testing see `Test
+Module`_ above.
+
+The tests from tools/testing/selftests/seccomp/seccomp_bpf.c can be used as
+example.
 
 Example
 -------
diff --git a/tools/testing/selftests/kselftest_module.h b/tools/testing/selftests/kselftest_module.h
new file mode 100644
index 000000000000..e8eafaf0941a
--- /dev/null
+++ b/tools/testing/selftests/kselftest_module.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef __KSELFTEST_MODULE_H
+#define __KSELFTEST_MODULE_H
+
+#include <linux/module.h>
+
+/*
+ * Test framework for writing test modules to be loaded by kselftest.
+ * See Documentation/dev-tools/kselftest.rst for an example test module.
+ */
+
+#define KSTM_MODULE_GLOBALS()			\
+static unsigned int total_tests __initdata;	\
+static unsigned int failed_tests __initdata
+
+#define KSTM_CHECK_ZERO(x) do {						\
+	total_tests++;							\
+	if (x) {							\
+		pr_warn("TC failed at %s:%d\n", __func__, __LINE__);	\
+		failed_tests++;						\
+	}								\
+} while (0)
+
+static inline int kstm_report(unsigned int total_tests, unsigned int failed_tests)
+{
+	if (failed_tests == 0)
+		pr_info("all %u tests passed\n", total_tests);
+	else
+		pr_warn("failed %u out of %u tests\n", failed_tests, total_tests);
+
+	return failed_tests ? -EINVAL : 0;
+}
+
+#define KSTM_MODULE_LOADERS(__module)			\
+static int __init __module##_init(void)			\
+{							\
+	pr_info("loaded.\n");				\
+	selftest();					\
+	return kstm_report(total_tests, failed_tests);	\
+}							\
+static void __exit __module##_exit(void)		\
+{							\
+	pr_info("unloaded.\n");				\
+}							\
+module_init(__module##_init);				\
+module_exit(__module##_exit)
+
+#endif	/* __KSELFTEST_MODULE_H */
-- 
2.21.0

[PATCH v4 3/6] kselftest: Add test module framework header

[Tobin C. Harding]

kselftest runs as a userspace process.  Sometimes we need to test things
from kernel space.  One way of doing this is by creating a test module.
Currently doing so requires developers to write a bunch of boiler plate
in the module if kselftest is to be used to run the tests.  This means
we currently have a load of duplicate code to achieve these ends.  If we
have a uniform method for implementing test modules then we can reduce
code duplication, ensure uniformity in the test framework, ease code
maintenance, and reduce the work required to create tests.  This all
helps to encourage developers to write and run tests.

Add a C header file that can be included in test modules.  This provides
a single point for common test functions/macros.  Implement a few macros
that make up the start of the test framework.

Add documentation for new kselftest header to kselftest documentation.

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 Documentation/dev-tools/kselftest.rst      | 94 +++++++++++++++++++++-
 tools/testing/selftests/kselftest_module.h | 48 +++++++++++
 2 files changed, 140 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/kselftest_module.h

diff --git a/Documentation/dev-tools/kselftest.rst b/Documentation/dev-tools/kselftest.rst
index 7756f7a7c23b..c8c03388b9de 100644
--- a/Documentation/dev-tools/kselftest.rst
+++ b/Documentation/dev-tools/kselftest.rst
@@ -14,6 +14,10 @@ in safe mode with a limited scope. In limited mode, cpu-hotplug test is
 run on a single cpu as opposed to all hotplug capable cpus, and memory
 hotplug test is run on 2% of hotplug capable memory instead of 10%.
 
+kselftest runs as a userspace process.  Tests that can be written/run in
+userspace may wish to use the `Test Harness`_.  Tests that need to be
+run in kernel space may wish to use a `Test Module`_.
+
 Running the selftests (hotplug tests are run in limited mode)
 =============================================================
 
@@ -161,11 +165,97 @@ Contributing new tests (details)
 
    e.g: tools/testing/selftests/android/config
 
+Test Module
+===========
+
+Kselftest tests the kernel from userspace.  Sometimes things need
+testing from within the kernel, one method of doing this is to create a
+test module.  We can tie the module into the kselftest framework by
+using a shell script test runner.  ``kselftest_module.sh`` is designed
+to facilitate this process.  There is also a header file provided to
+assist writing kernel modules that are for use with kselftest:
+
+- ``tools/testing/kselftest/kselftest_module.h``
+- ``tools/testing/kselftest/kselftest_module.sh``
+
+How to use
+----------
+
+Here we show the typical steps to create a test module and tie it into
+kselftest.  We use kselftests for lib/ as an example.
+
+1. Create the test module
+
+2. Create the test script that will run (load/unload) the module
+   e.g. ``tools/testing/selftests/lib/printf.sh``
+
+3. Add line to config file e.g. ``tools/testing/selftests/lib/config``
+
+4. Add test script to makefile  e.g. ``tools/testing/selftests/lib/Makefile``
+
+5. Verify it works:
+
+.. code-block:: sh
+
+   # Assumes you have booted a fresh build of this kernel tree
+   cd /path/to/linux/tree
+   make kselftest-merge
+   make modules
+   sudo make modules_install
+   make TARGETS=lib kselftest
+
+Example Module
+--------------
+
+A bare bones test module might look like this:
+
+.. code-block:: c
+
+   // SPDX-License-Identifier: GPL-2.0+
+
+   #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+   #include "../tools/testing/selftests/kselftest_module.h"
+
+   KSTM_MODULE_GLOBALS();
+
+   /*
+    * Kernel module for testing the foobinator
+    */
+
+   static int __init test_function()
+   {
+           ...
+   }
+
+   static void __init selftest(void)
+   {
+           KSTM_CHECK_ZERO(do_test_case("", 0));
+   }
+
+   KSTM_MODULE_LOADERS(test_foo);
+   MODULE_AUTHOR("John Developer <jd at fooman.org>");
+   MODULE_LICENSE("GPL");
+
+Example test script
+-------------------
+
+.. code-block:: sh
+
+    #!/bin/bash
+    # SPDX-License-Identifier: GPL-2.0+
+    $(dirname $0)/../kselftest_module.sh "foo" test_foo
+
+
 Test Harness
 ============
 
-The kselftest_harness.h file contains useful helpers to build tests.  The tests
-from tools/testing/selftests/seccomp/seccomp_bpf.c can be used as example.
+The kselftest_harness.h file contains useful helpers to build tests.  The
+test harness is for userspace testing, for kernel space testing see `Test
+Module`_ above.
+
+The tests from tools/testing/selftests/seccomp/seccomp_bpf.c can be used as
+example.
 
 Example
 -------
diff --git a/tools/testing/selftests/kselftest_module.h b/tools/testing/selftests/kselftest_module.h
new file mode 100644
index 000000000000..e8eafaf0941a
--- /dev/null
+++ b/tools/testing/selftests/kselftest_module.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef __KSELFTEST_MODULE_H
+#define __KSELFTEST_MODULE_H
+
+#include <linux/module.h>
+
+/*
+ * Test framework for writing test modules to be loaded by kselftest.
+ * See Documentation/dev-tools/kselftest.rst for an example test module.
+ */
+
+#define KSTM_MODULE_GLOBALS()			\
+static unsigned int total_tests __initdata;	\
+static unsigned int failed_tests __initdata
+
+#define KSTM_CHECK_ZERO(x) do {						\
+	total_tests++;							\
+	if (x) {							\
+		pr_warn("TC failed at %s:%d\n", __func__, __LINE__);	\
+		failed_tests++;						\
+	}								\
+} while (0)
+
+static inline int kstm_report(unsigned int total_tests, unsigned int failed_tests)
+{
+	if (failed_tests == 0)
+		pr_info("all %u tests passed\n", total_tests);
+	else
+		pr_warn("failed %u out of %u tests\n", failed_tests, total_tests);
+
+	return failed_tests ? -EINVAL : 0;
+}
+
+#define KSTM_MODULE_LOADERS(__module)			\
+static int __init __module##_init(void)			\
+{							\
+	pr_info("loaded.\n");				\
+	selftest();					\
+	return kstm_report(total_tests, failed_tests);	\
+}							\
+static void __exit __module##_exit(void)		\
+{							\
+	pr_info("unloaded.\n");				\
+}							\
+module_init(__module##_init);				\
+module_exit(__module##_exit)
+
+#endif	/* __KSELFTEST_MODULE_H */
-- 
2.21.0

[PATCH v4 4/6] lib: Use new kselftest header

[tobin]

We just added a new C header file for use with test modules that are
intended to be run with kselftest.  We can reduce code duplication by
using this header.

Use new kselftest header to reduce code duplication in test_printf and
test_bitmap test modules.

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 lib/test_bitmap.c | 20 ++++----------------
 lib/test_printf.c | 23 +++++------------------
 2 files changed, 9 insertions(+), 34 deletions(-)

diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 6cd7d0740005..792d90608052 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -12,6 +12,8 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 
+#include "../tools/testing/selftests/kselftest_module.h"
+
 static unsigned total_tests __initdata;
 static unsigned failed_tests __initdata;
 
@@ -361,7 +363,7 @@ static void noinline __init test_mem_optimisations(void)
 	}
 }
 
-static int __init test_bitmap_init(void)
+static void __init selftest(void)
 {
 	test_zero_clear();
 	test_fill_set();
@@ -369,22 +371,8 @@ static int __init test_bitmap_init(void)
 	test_bitmap_arr32();
 	test_bitmap_parselist();
 	test_mem_optimisations();
-
-	if (failed_tests == 0)
-		pr_info("all %u tests passed\n", total_tests);
-	else
-		pr_warn("failed %u out of %u tests\n",
-			failed_tests, total_tests);
-
-	return failed_tests ? -EINVAL : 0;
 }
 
-static void __exit test_bitmap_cleanup(void)
-{
-}
-
-module_init(test_bitmap_init);
-module_exit(test_bitmap_cleanup);
-
+KSTM_MODULE_LOADERS(test_bitmap);
 MODULE_AUTHOR("david decotigny <david.decotigny at googlers.com>");
 MODULE_LICENSE("GPL");
diff --git a/lib/test_printf.c b/lib/test_printf.c
index 601e8519319a..f4fcc1c43739 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -21,6 +21,8 @@
 #include <linux/gfp.h>
 #include <linux/mm.h>
 
+#include "../tools/testing/selftests/kselftest_module.h"
+
 #define BUF_SIZE 256
 #define PAD_SIZE 16
 #define FILL_CHAR '$'
@@ -590,12 +592,11 @@ test_pointer(void)
 	flags();
 }
 
-static int __init
-test_printf_init(void)
+static void __init selftest(void)
 {
 	alloced_buffer = kmalloc(BUF_SIZE + 2*PAD_SIZE, GFP_KERNEL);
 	if (!alloced_buffer)
-		return -ENOMEM;
+		return;
 	test_buffer = alloced_buffer + PAD_SIZE;
 
 	test_basic();
@@ -604,22 +605,8 @@ test_printf_init(void)
 	test_pointer();
 
 	kfree(alloced_buffer);
-
-	if (failed_tests == 0)
-		pr_info("all %u tests passed\n", total_tests);
-	else
-		pr_warn("failed %u out of %u tests\n", failed_tests, total_tests);
-
-	return failed_tests ? -EINVAL : 0;
 }
 
-module_init(test_printf_init);
-
-static void __exit test_printf_exit(void)
-{
-}
-
-module_exit(test_printf_exit);
-
+KSTM_MODULE_LOADERS(test_printf);
 MODULE_AUTHOR("Rasmus Villemoes <linux at rasmusvillemoes.dk>");
 MODULE_LICENSE("GPL");
-- 
2.21.0

[PATCH v4 4/6] lib: Use new kselftest header

[Tobin C. Harding]

We just added a new C header file for use with test modules that are
intended to be run with kselftest.  We can reduce code duplication by
using this header.

Use new kselftest header to reduce code duplication in test_printf and
test_bitmap test modules.

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 lib/test_bitmap.c | 20 ++++----------------
 lib/test_printf.c | 23 +++++------------------
 2 files changed, 9 insertions(+), 34 deletions(-)

diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 6cd7d0740005..792d90608052 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -12,6 +12,8 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 
+#include "../tools/testing/selftests/kselftest_module.h"
+
 static unsigned total_tests __initdata;
 static unsigned failed_tests __initdata;
 
@@ -361,7 +363,7 @@ static void noinline __init test_mem_optimisations(void)
 	}
 }
 
-static int __init test_bitmap_init(void)
+static void __init selftest(void)
 {
 	test_zero_clear();
 	test_fill_set();
@@ -369,22 +371,8 @@ static int __init test_bitmap_init(void)
 	test_bitmap_arr32();
 	test_bitmap_parselist();
 	test_mem_optimisations();
-
-	if (failed_tests == 0)
-		pr_info("all %u tests passed\n", total_tests);
-	else
-		pr_warn("failed %u out of %u tests\n",
-			failed_tests, total_tests);
-
-	return failed_tests ? -EINVAL : 0;
 }
 
-static void __exit test_bitmap_cleanup(void)
-{
-}
-
-module_init(test_bitmap_init);
-module_exit(test_bitmap_cleanup);
-
+KSTM_MODULE_LOADERS(test_bitmap);
 MODULE_AUTHOR("david decotigny <david.decotigny at googlers.com>");
 MODULE_LICENSE("GPL");
diff --git a/lib/test_printf.c b/lib/test_printf.c
index 601e8519319a..f4fcc1c43739 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -21,6 +21,8 @@
 #include <linux/gfp.h>
 #include <linux/mm.h>
 
+#include "../tools/testing/selftests/kselftest_module.h"
+
 #define BUF_SIZE 256
 #define PAD_SIZE 16
 #define FILL_CHAR '$'
@@ -590,12 +592,11 @@ test_pointer(void)
 	flags();
 }
 
-static int __init
-test_printf_init(void)
+static void __init selftest(void)
 {
 	alloced_buffer = kmalloc(BUF_SIZE + 2*PAD_SIZE, GFP_KERNEL);
 	if (!alloced_buffer)
-		return -ENOMEM;
+		return;
 	test_buffer = alloced_buffer + PAD_SIZE;
 
 	test_basic();
@@ -604,22 +605,8 @@ test_printf_init(void)
 	test_pointer();
 
 	kfree(alloced_buffer);
-
-	if (failed_tests == 0)
-		pr_info("all %u tests passed\n", total_tests);
-	else
-		pr_warn("failed %u out of %u tests\n", failed_tests, total_tests);
-
-	return failed_tests ? -EINVAL : 0;
 }
 
-module_init(test_printf_init);
-
-static void __exit test_printf_exit(void)
-{
-}
-
-module_exit(test_printf_exit);
-
+KSTM_MODULE_LOADERS(test_printf);
 MODULE_AUTHOR("Rasmus Villemoes <linux at rasmusvillemoes.dk>");
 MODULE_LICENSE("GPL");
-- 
2.21.0

[PATCH v4 5/6] lib/string: Add strscpy_pad() function

[tobin]

We have a function to copy strings safely and we have a function to copy
strings and zero the tail of the destination (if source string is
shorter than destination buffer) but we do not have a function to do
both at once.  This means developers must write this themselves if they
desire this functionality.  This is a chore, and also leaves us open to
off by one errors unnecessarily.

Add a function that calls strscpy() then memset()s the tail to zero if
the source string is shorter than the destination buffer.

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 include/linux/string.h |  4 ++++
 lib/string.c           | 47 +++++++++++++++++++++++++++++++++++-------
 2 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/include/linux/string.h b/include/linux/string.h
index 7927b875f80c..bfe95bf5d07e 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -31,6 +31,10 @@ size_t strlcpy(char *, const char *, size_t);
 #ifndef __HAVE_ARCH_STRSCPY
 ssize_t strscpy(char *, const char *, size_t);
 #endif
+
+/* Wraps calls to strscpy()/memset(), no arch specific code required */
+ssize_t strscpy_pad(char *dest, const char *src, size_t count);
+
 #ifndef __HAVE_ARCH_STRCAT
 extern char * strcat(char *, const char *);
 #endif
diff --git a/lib/string.c b/lib/string.c
index 38e4ca08e757..3a3353512184 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -159,11 +159,9 @@ EXPORT_SYMBOL(strlcpy);
  * @src: Where to copy the string from
  * @count: Size of destination buffer
  *
- * Copy the string, or as much of it as fits, into the dest buffer.
- * The routine returns the number of characters copied (not including
- * the trailing NUL) or -E2BIG if the destination buffer wasn't big enough.
- * The behavior is undefined if the string buffers overlap.
- * The destination buffer is always NUL terminated, unless it's zero-sized.
+ * Copy the string, or as much of it as fits, into the dest buffer.  The
+ * behavior is undefined if the string buffers overlap.  The destination
+ * buffer is always NUL terminated, unless it's zero-sized.
  *
  * Preferred to strlcpy() since the API doesn't require reading memory
  * from the src string beyond the specified "count" bytes, and since
@@ -173,8 +171,10 @@ EXPORT_SYMBOL(strlcpy);
  *
  * Preferred to strncpy() since it always returns a valid string, and
  * doesn't unnecessarily force the tail of the destination buffer to be
- * zeroed.  If the zeroing is desired, it's likely cleaner to use strscpy()
- * with an overflow test, then just memset() the tail of the dest buffer.
+ * zeroed.  If zeroing is desired please use strscpy_pad().
+ *
+ * Return: The number of characters copied (not including the trailing
+ *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
  */
 ssize_t strscpy(char *dest, const char *src, size_t count)
 {
@@ -237,6 +237,39 @@ ssize_t strscpy(char *dest, const char *src, size_t count)
 EXPORT_SYMBOL(strscpy);
 #endif
 
+/**
+ * strscpy_pad() - Copy a C-string into a sized buffer
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ * @count: Size of destination buffer
+ *
+ * Copy the string, or as much of it as fits, into the dest buffer.  The
+ * behavior is undefined if the string buffers overlap.  The destination
+ * buffer is always %NUL terminated, unless it's zero-sized.
+ *
+ * If the source string is shorter than the destination buffer, zeros
+ * the tail of the destination buffer.
+ *
+ * For full explanation of why you may want to consider using the
+ * 'strscpy' functions please see the function docstring for strscpy().
+ *
+ * Return: The number of characters copied (not including the trailing
+ *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
+ */
+ssize_t strscpy_pad(char *dest, const char *src, size_t count)
+{
+	ssize_t written;
+
+	written = strscpy(dest, src, count);
+	if (written < 0 || written == count - 1)
+		return written;
+
+	memset(dest + written + 1, 0, count - written - 1);
+
+	return written;
+}
+EXPORT_SYMBOL(strscpy_pad);
+
 #ifndef __HAVE_ARCH_STRCAT
 /**
  * strcat - Append one %NUL-terminated string to another
-- 
2.21.0

[PATCH v4 5/6] lib/string: Add strscpy_pad() function

[Tobin C. Harding]

We have a function to copy strings safely and we have a function to copy
strings and zero the tail of the destination (if source string is
shorter than destination buffer) but we do not have a function to do
both at once.  This means developers must write this themselves if they
desire this functionality.  This is a chore, and also leaves us open to
off by one errors unnecessarily.

Add a function that calls strscpy() then memset()s the tail to zero if
the source string is shorter than the destination buffer.

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 include/linux/string.h |  4 ++++
 lib/string.c           | 47 +++++++++++++++++++++++++++++++++++-------
 2 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/include/linux/string.h b/include/linux/string.h
index 7927b875f80c..bfe95bf5d07e 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -31,6 +31,10 @@ size_t strlcpy(char *, const char *, size_t);
 #ifndef __HAVE_ARCH_STRSCPY
 ssize_t strscpy(char *, const char *, size_t);
 #endif
+
+/* Wraps calls to strscpy()/memset(), no arch specific code required */
+ssize_t strscpy_pad(char *dest, const char *src, size_t count);
+
 #ifndef __HAVE_ARCH_STRCAT
 extern char * strcat(char *, const char *);
 #endif
diff --git a/lib/string.c b/lib/string.c
index 38e4ca08e757..3a3353512184 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -159,11 +159,9 @@ EXPORT_SYMBOL(strlcpy);
  * @src: Where to copy the string from
  * @count: Size of destination buffer
  *
- * Copy the string, or as much of it as fits, into the dest buffer.
- * The routine returns the number of characters copied (not including
- * the trailing NUL) or -E2BIG if the destination buffer wasn't big enough.
- * The behavior is undefined if the string buffers overlap.
- * The destination buffer is always NUL terminated, unless it's zero-sized.
+ * Copy the string, or as much of it as fits, into the dest buffer.  The
+ * behavior is undefined if the string buffers overlap.  The destination
+ * buffer is always NUL terminated, unless it's zero-sized.
  *
  * Preferred to strlcpy() since the API doesn't require reading memory
  * from the src string beyond the specified "count" bytes, and since
@@ -173,8 +171,10 @@ EXPORT_SYMBOL(strlcpy);
  *
  * Preferred to strncpy() since it always returns a valid string, and
  * doesn't unnecessarily force the tail of the destination buffer to be
- * zeroed.  If the zeroing is desired, it's likely cleaner to use strscpy()
- * with an overflow test, then just memset() the tail of the dest buffer.
+ * zeroed.  If zeroing is desired please use strscpy_pad().
+ *
+ * Return: The number of characters copied (not including the trailing
+ *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
  */
 ssize_t strscpy(char *dest, const char *src, size_t count)
 {
@@ -237,6 +237,39 @@ ssize_t strscpy(char *dest, const char *src, size_t count)
 EXPORT_SYMBOL(strscpy);
 #endif
 
+/**
+ * strscpy_pad() - Copy a C-string into a sized buffer
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ * @count: Size of destination buffer
+ *
+ * Copy the string, or as much of it as fits, into the dest buffer.  The
+ * behavior is undefined if the string buffers overlap.  The destination
+ * buffer is always %NUL terminated, unless it's zero-sized.
+ *
+ * If the source string is shorter than the destination buffer, zeros
+ * the tail of the destination buffer.
+ *
+ * For full explanation of why you may want to consider using the
+ * 'strscpy' functions please see the function docstring for strscpy().
+ *
+ * Return: The number of characters copied (not including the trailing
+ *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
+ */
+ssize_t strscpy_pad(char *dest, const char *src, size_t count)
+{
+	ssize_t written;
+
+	written = strscpy(dest, src, count);
+	if (written < 0 || written == count - 1)
+		return written;
+
+	memset(dest + written + 1, 0, count - written - 1);
+
+	return written;
+}
+EXPORT_SYMBOL(strscpy_pad);
+
 #ifndef __HAVE_ARCH_STRCAT
 /**
  * strcat - Append one %NUL-terminated string to another
-- 
2.21.0

[PATCH v4 6/6] lib: Add test module for strscpy_pad

[tobin]

Add a test module for the new strscpy_pad() function.  Tie it into the
kselftest infrastructure for lib/ tests.

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 lib/Kconfig.debug                      |   3 +
 lib/Makefile                           |   1 +
 lib/test_strscpy.c                     | 150 +++++++++++++++++++++++++
 tools/testing/selftests/lib/Makefile   |   2 +-
 tools/testing/selftests/lib/config     |   1 +
 tools/testing/selftests/lib/strscpy.sh |   3 +
 6 files changed, 159 insertions(+), 1 deletion(-)
 create mode 100644 lib/test_strscpy.c
 create mode 100755 tools/testing/selftests/lib/strscpy.sh

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 0d9e81779e37..4b644ad399dd 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1769,6 +1769,9 @@ config TEST_HEXDUMP
 config TEST_STRING_HELPERS
 	tristate "Test functions located in the string_helpers module at runtime"
 
+config TEST_STRSCPY
+	tristate "Test strscpy*() family of functions at runtime"
+
 config TEST_KSTRTOX
 	tristate "Test kstrto*() family of functions at runtime"
 
diff --git a/lib/Makefile b/lib/Makefile
index 3b08673e8881..b4e08d6234ba 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -70,6 +70,7 @@ obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
 obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
 obj-$(CONFIG_TEST_PRINTF) += test_printf.o
 obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
+obj-$(CONFIG_TEST_STRSCPY) += test_strscpy.o
 obj-$(CONFIG_TEST_BITFIELD) += test_bitfield.o
 obj-$(CONFIG_TEST_UUID) += test_uuid.o
 obj-$(CONFIG_TEST_XARRAY) += test_xarray.o
diff --git a/lib/test_strscpy.c b/lib/test_strscpy.c
new file mode 100644
index 000000000000..a827f94601f5
--- /dev/null
+++ b/lib/test_strscpy.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/string.h>
+
+#include "../tools/testing/selftests/kselftest_module.h"
+
+/*
+ * Kernel module for testing 'strscpy' family of functions.
+ */
+
+KSTM_MODULE_GLOBALS();
+
+/*
+ * tc() - Run a specific test case.
+ * @src: Source string, argument to strscpy_pad()
+ * @count: Size of destination buffer, argument to strscpy_pad()
+ * @expected: Expected return value from call to strscpy_pad()
+ * @terminator: 1 if there should be a terminating null byte 0 otherwise.
+ * @chars: Number of characters from the src string expected to be
+ *         written to the dst buffer.
+ * @pad: Number of pad characters expected (in the tail of dst buffer).
+ *       (@pad does not include the null terminator byte.)
+ *
+ * Calls strscpy_pad() and verifies the return value and state of the
+ * destination buffer after the call returns.
+ */
+static int __init tc(char *src, int count, int expected,
+		     int chars, int terminator, int pad)
+{
+	int nr_bytes_poison;
+	int max_expected;
+	int max_count;
+	int written;
+	char buf[6];
+	int index, i;
+	const char POISON = 'z';
+
+	total_tests++;
+
+	if (!src) {
+		pr_err("null source string not supported\n");
+		return -1;
+	}
+
+	memset(buf, POISON, sizeof(buf));
+	/* Future proofing test suite, validate args */
+	max_count = sizeof(buf) - 2; /* Space for null and to verify overflow */
+	max_expected = count - 1;    /* Space for the null */
+	if (count > max_count) {
+		pr_err("count (%d) is too big (%d) ... aborting", count, max_count);
+		return -1;
+	}
+	if (expected > max_expected) {
+		pr_warn("expected (%d) is bigger than can possibly be returned (%d)",
+			expected, max_expected);
+	}
+
+	written = strscpy_pad(buf, src, count);
+	if ((written) != (expected)) {
+		pr_err("%d != %d (written, expected)\n", written, expected);
+		goto fail;
+	}
+
+	if (count && written == -E2BIG) {
+		if (strncmp(buf, src, count - 1) != 0) {
+			pr_err("buffer state invalid for -E2BIG\n");
+			goto fail;
+		}
+		if (buf[count - 1] != '\0') {
+			pr_err("too big string is not null terminated correctly\n");
+			goto fail;
+		}
+	}
+
+	for (i = 0; i < chars; i++) {
+		if (buf[i] != src[i]) {
+			pr_err("buf[i]==%c != src[i]==%c\n", buf[i], src[i]);
+			goto fail;
+		}
+	}
+
+	if (terminator) {
+		if (buf[count - 1] != '\0') {
+			pr_err("string is not null terminated correctly\n");
+			goto fail;
+		}
+	}
+
+	for (i = 0; i < pad; i++) {
+		index = chars + terminator + i;
+		if (buf[index] != '\0') {
+			pr_err("padding missing at index: %d\n", i);
+			goto fail;
+		}
+	}
+
+	nr_bytes_poison = sizeof(buf) - chars - terminator - pad;
+	for (i = 0; i < nr_bytes_poison; i++) {
+		index = sizeof(buf) - 1 - i; /* Check from the end back */
+		if (buf[index] != POISON) {
+			pr_err("poison value missing at index: %d\n", i);
+			goto fail;
+		}
+	}
+
+	return 0;
+fail:
+	failed_tests++;
+	return -1;
+}
+
+static void __init selftest(void)
+{
+	/*
+	 * tc() uses a destination buffer of size 6 and needs at
+	 * least 2 characters spare (one for null and one to check for
+	 * overflow).  This means we should only call tc() with
+	 * strings up to a maximum of 4 characters long and 'count'
+	 * should not exceed 4.  To test with longer strings increase
+	 * the buffer size in tc().
+	 */
+
+	/* tc(src, count, expected, chars, terminator, pad) */
+	KSTM_CHECK_ZERO(tc("a", 0, -E2BIG, 0, 0, 0));
+	KSTM_CHECK_ZERO(tc("", 0, -E2BIG, 0, 0, 0));
+
+	KSTM_CHECK_ZERO(tc("a", 1, -E2BIG, 0, 1, 0));
+	KSTM_CHECK_ZERO(tc("", 1, 0, 0, 1, 0));
+
+	KSTM_CHECK_ZERO(tc("ab", 2, -E2BIG, 1, 1, 0));
+	KSTM_CHECK_ZERO(tc("a", 2, 1, 1, 1, 0));
+	KSTM_CHECK_ZERO(tc("", 2, 0, 0, 1, 1));
+
+	KSTM_CHECK_ZERO(tc("abc", 3, -E2BIG, 2, 1, 0));
+	KSTM_CHECK_ZERO(tc("ab", 3, 2, 2, 1, 0));
+	KSTM_CHECK_ZERO(tc("a", 3, 1, 1, 1, 1));
+	KSTM_CHECK_ZERO(tc("", 3, 0, 0, 1, 2));
+
+	KSTM_CHECK_ZERO(tc("abcd", 4, -E2BIG, 3, 1, 0));
+	KSTM_CHECK_ZERO(tc("abc", 4, 3, 3, 1, 0));
+	KSTM_CHECK_ZERO(tc("ab", 4, 2, 2, 1, 1));
+	KSTM_CHECK_ZERO(tc("a", 4, 1, 1, 1, 2));
+	KSTM_CHECK_ZERO(tc("", 4, 0, 0, 1, 3));
+}
+
+KSTM_MODULE_LOADERS(test_strscpy);
+MODULE_AUTHOR("Tobin C. Harding <tobin at kernel.org>");
+MODULE_LICENSE("GPL");
diff --git a/tools/testing/selftests/lib/Makefile b/tools/testing/selftests/lib/Makefile
index 70d5711e3ac8..9f26635f3e57 100644
--- a/tools/testing/selftests/lib/Makefile
+++ b/tools/testing/selftests/lib/Makefile
@@ -3,6 +3,6 @@
 # No binaries, but make sure arg-less "make" doesn't trigger "run_tests"
 all:
 
-TEST_PROGS := printf.sh bitmap.sh prime_numbers.sh
+TEST_PROGS := printf.sh bitmap.sh prime_numbers.sh strscpy.sh
 
 include ../lib.mk
diff --git a/tools/testing/selftests/lib/config b/tools/testing/selftests/lib/config
index 126933bcc950..14a77ea4a8da 100644
--- a/tools/testing/selftests/lib/config
+++ b/tools/testing/selftests/lib/config
@@ -1,3 +1,4 @@
 CONFIG_TEST_PRINTF=m
 CONFIG_TEST_BITMAP=m
 CONFIG_PRIME_NUMBERS=m
+CONFIG_TEST_STRSCPY=m
diff --git a/tools/testing/selftests/lib/strscpy.sh b/tools/testing/selftests/lib/strscpy.sh
new file mode 100755
index 000000000000..71f2be6afba6
--- /dev/null
+++ b/tools/testing/selftests/lib/strscpy.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+$(dirname $0)/../kselftest_module.sh "strscpy*" test_strscpy
-- 
2.21.0

[PATCH v4 6/6] lib: Add test module for strscpy_pad

[Tobin C. Harding]

Add a test module for the new strscpy_pad() function.  Tie it into the
kselftest infrastructure for lib/ tests.

Acked-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Tobin C. Harding <tobin at kernel.org>
---
 lib/Kconfig.debug                      |   3 +
 lib/Makefile                           |   1 +
 lib/test_strscpy.c                     | 150 +++++++++++++++++++++++++
 tools/testing/selftests/lib/Makefile   |   2 +-
 tools/testing/selftests/lib/config     |   1 +
 tools/testing/selftests/lib/strscpy.sh |   3 +
 6 files changed, 159 insertions(+), 1 deletion(-)
 create mode 100644 lib/test_strscpy.c
 create mode 100755 tools/testing/selftests/lib/strscpy.sh

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 0d9e81779e37..4b644ad399dd 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1769,6 +1769,9 @@ config TEST_HEXDUMP
 config TEST_STRING_HELPERS
 	tristate "Test functions located in the string_helpers module at runtime"
 
+config TEST_STRSCPY
+	tristate "Test strscpy*() family of functions at runtime"
+
 config TEST_KSTRTOX
 	tristate "Test kstrto*() family of functions at runtime"
 
diff --git a/lib/Makefile b/lib/Makefile
index 3b08673e8881..b4e08d6234ba 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -70,6 +70,7 @@ obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
 obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
 obj-$(CONFIG_TEST_PRINTF) += test_printf.o
 obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
+obj-$(CONFIG_TEST_STRSCPY) += test_strscpy.o
 obj-$(CONFIG_TEST_BITFIELD) += test_bitfield.o
 obj-$(CONFIG_TEST_UUID) += test_uuid.o
 obj-$(CONFIG_TEST_XARRAY) += test_xarray.o
diff --git a/lib/test_strscpy.c b/lib/test_strscpy.c
new file mode 100644
index 000000000000..a827f94601f5
--- /dev/null
+++ b/lib/test_strscpy.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/string.h>
+
+#include "../tools/testing/selftests/kselftest_module.h"
+
+/*
+ * Kernel module for testing 'strscpy' family of functions.
+ */
+
+KSTM_MODULE_GLOBALS();
+
+/*
+ * tc() - Run a specific test case.
+ * @src: Source string, argument to strscpy_pad()
+ * @count: Size of destination buffer, argument to strscpy_pad()
+ * @expected: Expected return value from call to strscpy_pad()
+ * @terminator: 1 if there should be a terminating null byte 0 otherwise.
+ * @chars: Number of characters from the src string expected to be
+ *         written to the dst buffer.
+ * @pad: Number of pad characters expected (in the tail of dst buffer).
+ *       (@pad does not include the null terminator byte.)
+ *
+ * Calls strscpy_pad() and verifies the return value and state of the
+ * destination buffer after the call returns.
+ */
+static int __init tc(char *src, int count, int expected,
+		     int chars, int terminator, int pad)
+{
+	int nr_bytes_poison;
+	int max_expected;
+	int max_count;
+	int written;
+	char buf[6];
+	int index, i;
+	const char POISON = 'z';
+
+	total_tests++;
+
+	if (!src) {
+		pr_err("null source string not supported\n");
+		return -1;
+	}
+
+	memset(buf, POISON, sizeof(buf));
+	/* Future proofing test suite, validate args */
+	max_count = sizeof(buf) - 2; /* Space for null and to verify overflow */
+	max_expected = count - 1;    /* Space for the null */
+	if (count > max_count) {
+		pr_err("count (%d) is too big (%d) ... aborting", count, max_count);
+		return -1;
+	}
+	if (expected > max_expected) {
+		pr_warn("expected (%d) is bigger than can possibly be returned (%d)",
+			expected, max_expected);
+	}
+
+	written = strscpy_pad(buf, src, count);
+	if ((written) != (expected)) {
+		pr_err("%d != %d (written, expected)\n", written, expected);
+		goto fail;
+	}
+
+	if (count && written == -E2BIG) {
+		if (strncmp(buf, src, count - 1) != 0) {
+			pr_err("buffer state invalid for -E2BIG\n");
+			goto fail;
+		}
+		if (buf[count - 1] != '\0') {
+			pr_err("too big string is not null terminated correctly\n");
+			goto fail;
+		}
+	}
+
+	for (i = 0; i < chars; i++) {
+		if (buf[i] != src[i]) {
+			pr_err("buf[i]==%c != src[i]==%c\n", buf[i], src[i]);
+			goto fail;
+		}
+	}
+
+	if (terminator) {
+		if (buf[count - 1] != '\0') {
+			pr_err("string is not null terminated correctly\n");
+			goto fail;
+		}
+	}
+
+	for (i = 0; i < pad; i++) {
+		index = chars + terminator + i;
+		if (buf[index] != '\0') {
+			pr_err("padding missing at index: %d\n", i);
+			goto fail;
+		}
+	}
+
+	nr_bytes_poison = sizeof(buf) - chars - terminator - pad;
+	for (i = 0; i < nr_bytes_poison; i++) {
+		index = sizeof(buf) - 1 - i; /* Check from the end back */
+		if (buf[index] != POISON) {
+			pr_err("poison value missing at index: %d\n", i);
+			goto fail;
+		}
+	}
+
+	return 0;
+fail:
+	failed_tests++;
+	return -1;
+}
+
+static void __init selftest(void)
+{
+	/*
+	 * tc() uses a destination buffer of size 6 and needs at
+	 * least 2 characters spare (one for null and one to check for
+	 * overflow).  This means we should only call tc() with
+	 * strings up to a maximum of 4 characters long and 'count'
+	 * should not exceed 4.  To test with longer strings increase
+	 * the buffer size in tc().
+	 */
+
+	/* tc(src, count, expected, chars, terminator, pad) */
+	KSTM_CHECK_ZERO(tc("a", 0, -E2BIG, 0, 0, 0));
+	KSTM_CHECK_ZERO(tc("", 0, -E2BIG, 0, 0, 0));
+
+	KSTM_CHECK_ZERO(tc("a", 1, -E2BIG, 0, 1, 0));
+	KSTM_CHECK_ZERO(tc("", 1, 0, 0, 1, 0));
+
+	KSTM_CHECK_ZERO(tc("ab", 2, -E2BIG, 1, 1, 0));
+	KSTM_CHECK_ZERO(tc("a", 2, 1, 1, 1, 0));
+	KSTM_CHECK_ZERO(tc("", 2, 0, 0, 1, 1));
+
+	KSTM_CHECK_ZERO(tc("abc", 3, -E2BIG, 2, 1, 0));
+	KSTM_CHECK_ZERO(tc("ab", 3, 2, 2, 1, 0));
+	KSTM_CHECK_ZERO(tc("a", 3, 1, 1, 1, 1));
+	KSTM_CHECK_ZERO(tc("", 3, 0, 0, 1, 2));
+
+	KSTM_CHECK_ZERO(tc("abcd", 4, -E2BIG, 3, 1, 0));
+	KSTM_CHECK_ZERO(tc("abc", 4, 3, 3, 1, 0));
+	KSTM_CHECK_ZERO(tc("ab", 4, 2, 2, 1, 1));
+	KSTM_CHECK_ZERO(tc("a", 4, 1, 1, 1, 2));
+	KSTM_CHECK_ZERO(tc("", 4, 0, 0, 1, 3));
+}
+
+KSTM_MODULE_LOADERS(test_strscpy);
+MODULE_AUTHOR("Tobin C. Harding <tobin at kernel.org>");
+MODULE_LICENSE("GPL");
diff --git a/tools/testing/selftests/lib/Makefile b/tools/testing/selftests/lib/Makefile
index 70d5711e3ac8..9f26635f3e57 100644
--- a/tools/testing/selftests/lib/Makefile
+++ b/tools/testing/selftests/lib/Makefile
@@ -3,6 +3,6 @@
 # No binaries, but make sure arg-less "make" doesn't trigger "run_tests"
 all:
 
-TEST_PROGS := printf.sh bitmap.sh prime_numbers.sh
+TEST_PROGS := printf.sh bitmap.sh prime_numbers.sh strscpy.sh
 
 include ../lib.mk
diff --git a/tools/testing/selftests/lib/config b/tools/testing/selftests/lib/config
index 126933bcc950..14a77ea4a8da 100644
--- a/tools/testing/selftests/lib/config
+++ b/tools/testing/selftests/lib/config
@@ -1,3 +1,4 @@
 CONFIG_TEST_PRINTF=m
 CONFIG_TEST_BITMAP=m
 CONFIG_PRIME_NUMBERS=m
+CONFIG_TEST_STRSCPY=m
diff --git a/tools/testing/selftests/lib/strscpy.sh b/tools/testing/selftests/lib/strscpy.sh
new file mode 100755
index 000000000000..71f2be6afba6
--- /dev/null
+++ b/tools/testing/selftests/lib/strscpy.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+$(dirname $0)/../kselftest_module.sh "strscpy*" test_strscpy
-- 
2.21.0

[PATCH v4 0/6] lib/string: Add strscpy_pad() function

[me]

On Fri, Apr 05, 2019 at 12:58:53PM +1100, Tobin C. Harding wrote:
> Hi Shua,

Apologies for continually leaving off the 'h' from your name Shuah.


	Tobin

[PATCH v4 0/6] lib/string: Add strscpy_pad() function

[Tobin C. Harding]

On Fri, Apr 05, 2019@12:58:53PM +1100, Tobin C. Harding wrote:
> Hi Shua,

Apologies for continually leaving off the 'h' from your name Shuah.


	Tobin

[PATCH v4 0/6] lib/string: Add strscpy_pad() function

[shuah]

On 4/4/19 7:58 PM, Tobin C. Harding wrote:
> Hi Shua,
> 
> Here is the set with cleanup as suggested by Kees on v3.
> 
> Configured, built, and tested all modules loaded by
> tools/testing/selftests/lib/*.sh
> 
>>From previous cover letters ...
> 
> While doing the testing for strscpy_pad() it was noticed that there is
> duplication in how test modules are being fed to kselftest and also in
> the test modules themselves.
> 
> This set makes an attempt at adding a framework to kselftest for writing
> kernel test modules.  It also adds a script for use in creating script
> test runners for kselftest.  My macro-foo is not great, all criticism
> and suggestions very much appreciated.  The design is based on test
> modules lib/test_printf.c, lib/test_bitmap.c, lib/test_xarray.c.
> 
> Changes since last version:
> 
>   - Remove dependency on Bash (thanks Kees)
>   - Use oneliner to implement kselftest test runners (thanks Kees)
>   - Squash patch that adds kselftest script creator script with patch
>     that uses it.
>   - Fix typos (thanks Randy)
>   - Add Kees' Acked-by tags to all patches
> 
> thanks,
> Tobin.
> 
> 

Hi Tobin,

Thanks for this restructuring work and adding the framework. Thanks Kees
for the reviews.

The patch is series in now in linux-kselftest next for 5.2

thanks,
-- Shuah

[PATCH v4 0/6] lib/string: Add strscpy_pad() function

[shuah]

On 4/4/19 7:58 PM, Tobin C. Harding wrote:
> Hi Shua,
> 
> Here is the set with cleanup as suggested by Kees on v3.
> 
> Configured, built, and tested all modules loaded by
> tools/testing/selftests/lib/*.sh
> 
>>From previous cover letters ...
> 
> While doing the testing for strscpy_pad() it was noticed that there is
> duplication in how test modules are being fed to kselftest and also in
> the test modules themselves.
> 
> This set makes an attempt at adding a framework to kselftest for writing
> kernel test modules.  It also adds a script for use in creating script
> test runners for kselftest.  My macro-foo is not great, all criticism
> and suggestions very much appreciated.  The design is based on test
> modules lib/test_printf.c, lib/test_bitmap.c, lib/test_xarray.c.
> 
> Changes since last version:
> 
>   - Remove dependency on Bash (thanks Kees)
>   - Use oneliner to implement kselftest test runners (thanks Kees)
>   - Squash patch that adds kselftest script creator script with patch
>     that uses it.
>   - Fix typos (thanks Randy)
>   - Add Kees' Acked-by tags to all patches
> 
> thanks,
> Tobin.
> 
> 

Hi Tobin,

Thanks for this restructuring work and adding the framework. Thanks Kees
for the reviews.

The patch is series in now in linux-kselftest next for 5.2

thanks,
-- Shuah

[PATCH v4 0/6] lib/string: Add strscpy_pad() function

[keescook]

On Mon, Apr 8, 2019 at 7:09 AM shuah <shuah at kernel.org> wrote:
> The patch is series in now in linux-kselftest next for 5.2

Yay, awesome! :) Thanks!

-- 
Kees Cook

[PATCH v4 0/6] lib/string: Add strscpy_pad() function

[Kees Cook]

On Mon, Apr 8, 2019@7:09 AM shuah <shuah@kernel.org> wrote:
> The patch is series in now in linux-kselftest next for 5.2

Yay, awesome! :) Thanks!

-- 
Kees Cook

Re: [PATCH v4 2/6] kselftest: Add test runner creation script

[Naresh Kamboju]

Hi Tobin,

On Fri, 5 Apr 2019 at 07:30, Tobin C. Harding <tobin@kernel.org> wrote:
>
> Currently if we wish to use kselftest to run tests within a kernel
> module we write a small script to load/unload and do error reporting.
> There are a bunch of these under tools/testing/selftests/lib/ that are
> all identical except for the test name.  We can reduce code duplication
> and improve maintainability if we have one version of this.  However
> kselftest requires an executable for each test.  We can move all the
> script logic to a central script then have each individual test script
> call the main script.
>
> Oneliner to call kselftest_module.sh courtesy of Kees, thanks!
>
> Add test runner creation script.  Convert
> tools/testing/selftests/lib/*.sh to use new test creation script.
>
> Testing
> -------
>
> Configure kselftests for lib/ then build and boot kernel.  Then run
> kselftests as follows:
>
>   $ cd /path/to/kernel/tree
>   $ sudo make O=$output_path -C tools/testing/selftests TARGETS="lib" run_tests

We are missing "kselftest_module.sh" file when we do "make install"
and followed by generating a tar file "gen_kselftest_tar.sh" and
copying that on to target device and running tests by using
"run_kselftest.sh" script file on the target.

Could you install the supporting script file "kselftest_module.sh" ?

Error log,
-------------
# selftests lib printf.sh
lib: printf.sh_ #
# ./printf.sh line 4 ./../kselftest_module.sh No such file or directory
line: 4_./../kselftest_module.sh #
[FAIL] 1 selftests lib printf.sh # exit=127
selftests: lib_printf.sh [FAIL]
# selftests lib bitmap.sh
lib: bitmap.sh_ #
# ./bitmap.sh line 3 ./../kselftest_module.sh No such file or directory
line: 3_./../kselftest_module.sh #
[FAIL] 2 selftests lib bitmap.sh # exit=127
selftests: lib_bitmap.sh [FAIL]
# selftests lib prime_numbers.sh
lib: prime_numbers.sh_ #
# ./prime_numbers.sh line 4 ./../kselftest_module.sh No such file or directory
line: 4_./../kselftest_module.sh #
[FAIL] 3 selftests lib prime_numbers.sh # exit=127
selftests: lib_prime_numbers.sh [FAIL]
# selftests lib strscpy.sh
lib: strscpy.sh_ #
# ./strscpy.sh line 3 ./../kselftest_module.sh No such file or directory
line: 3_./../kselftest_module.sh #
[FAIL] 4 selftests lib strscpy.sh # exit=127
selftests: lib_strscpy.sh [FAIL]

- Naresh

Re: [PATCH v4 2/6] kselftest: Add test runner creation script

[Kees Cook]

On Wed, Oct 30, 2019 at 06:15:22PM +0530, Naresh Kamboju wrote:
> Hi Tobin,
> 
> On Fri, 5 Apr 2019 at 07:30, Tobin C. Harding <tobin@kernel.org> wrote:
> >
> > Currently if we wish to use kselftest to run tests within a kernel
> > module we write a small script to load/unload and do error reporting.
> > There are a bunch of these under tools/testing/selftests/lib/ that are
> > all identical except for the test name.  We can reduce code duplication
> > and improve maintainability if we have one version of this.  However
> > kselftest requires an executable for each test.  We can move all the
> > script logic to a central script then have each individual test script
> > call the main script.
> >
> > Oneliner to call kselftest_module.sh courtesy of Kees, thanks!
> >
> > Add test runner creation script.  Convert
> > tools/testing/selftests/lib/*.sh to use new test creation script.
> >
> > Testing
> > -------
> >
> > Configure kselftests for lib/ then build and boot kernel.  Then run
> > kselftests as follows:
> >
> >   $ cd /path/to/kernel/tree
> >   $ sudo make O=$output_path -C tools/testing/selftests TARGETS="lib" run_tests
> 
> We are missing "kselftest_module.sh" file when we do "make install"
> and followed by generating a tar file "gen_kselftest_tar.sh" and
> copying that on to target device and running tests by using
> "run_kselftest.sh" script file on the target.

Yikes -- there's a problem with gen_kselftest_tar.sh using the wrong
directory. I'll send a patch...

-Kees

> 
> Could you install the supporting script file "kselftest_module.sh" ?
> 
> Error log,
> -------------
> # selftests lib printf.sh
> lib: printf.sh_ #
> # ./printf.sh line 4 ./../kselftest_module.sh No such file or directory
> line: 4_./../kselftest_module.sh #
> [FAIL] 1 selftests lib printf.sh # exit=127
> selftests: lib_printf.sh [FAIL]
> # selftests lib bitmap.sh
> lib: bitmap.sh_ #
> # ./bitmap.sh line 3 ./../kselftest_module.sh No such file or directory
> line: 3_./../kselftest_module.sh #
> [FAIL] 2 selftests lib bitmap.sh # exit=127
> selftests: lib_bitmap.sh [FAIL]
> # selftests lib prime_numbers.sh
> lib: prime_numbers.sh_ #
> # ./prime_numbers.sh line 4 ./../kselftest_module.sh No such file or directory
> line: 4_./../kselftest_module.sh #
> [FAIL] 3 selftests lib prime_numbers.sh # exit=127
> selftests: lib_prime_numbers.sh [FAIL]
> # selftests lib strscpy.sh
> lib: strscpy.sh_ #
> # ./strscpy.sh line 3 ./../kselftest_module.sh No such file or directory
> line: 3_./../kselftest_module.sh #
> [FAIL] 4 selftests lib strscpy.sh # exit=127
> selftests: lib_strscpy.sh [FAIL]
> 
> - Naresh

-- 
Kees Cook