Acked-by: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
>
> Signed-off-by: Thomas WeiÃ?schuh <thomas.weissschuh@xxxxxxxxxxxxx>
> Reviewed-by: David Gow <davidgow@xxxxxxxxxx>
> ---
> MAINTAINERS | 1 +
> lib/kunit/Makefile | 6 +++++
> lib/kunit/kunit-uapi.c | 9 +++++--
> lib/kunit/uapi-preinit.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 77 insertions(+), 2 deletions(-)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index b1405f0a0e638d1654d9dc9e51d784ddc838cf5b..e81dfa180ab374ef91c7a45e546e6e9a8f454fa7 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13546,6 +13546,7 @@ S: Maintained
> F: include/kunit/uapi.h
> F: lib/kunit/kunit-example-uapi.c
> F: lib/kunit/kunit-uapi.c
> +F: lib/kunit/uapi-preinit.c
>
> KVM PARAVIRT (KVM/paravirt)
> M: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> diff --git a/lib/kunit/Makefile b/lib/kunit/Makefile
> index 1bba7965613e36e26939d6b31e1d65acf5bad0dc..b50f3bc8bc7f3ade03be4900d9163d7a0d96863c 100644
> --- a/lib/kunit/Makefile
> +++ b/lib/kunit/Makefile
> @@ -14,8 +14,14 @@ kunit-objs += test.o \
> device.o \
> platform.o
>
> +userprogs += uapi-preinit
> +uapi-preinit-userccflags += -static $(NOLIBC_USERCFLAGS) \
> + -include include/generated/autoconf.h \
> + -include $(srctree)/tools/include/linux/kconfig.h
> obj-$(CONFIG_KUNIT_UAPI) += kunit-uapi.o
>
> +$(obj)/kunit-uapi.o: $(obj)/uapi-preinit
> +
> ifeq ($(CONFIG_KUNIT_DEBUGFS),y)
> kunit-objs += debugfs.o
> endif
> diff --git a/lib/kunit/kunit-uapi.c b/lib/kunit/kunit-uapi.c
> index cfe8440e16fde942a5f0fa7ac9d8ab90a737215b..7c87605b9ded9dbeb3968af8a8f4650ab5938887 100644
> --- a/lib/kunit/kunit-uapi.c
> +++ b/lib/kunit/kunit-uapi.c
> @@ -25,6 +25,8 @@
> #define KSFT_XPASS 3
> #define KSFT_SKIP 4
>
> +KUNIT_UAPI_EMBED_BLOB(kunit_uapi_preinit, "uapi-preinit");
> +
> static struct vfsmount *kunit_uapi_mount_ramfs(void)
> {
> struct file_system_type *type;
> @@ -146,7 +148,7 @@ static int kunit_uapi_user_mode_thread_init(void *data)
> kernel_sigaction(SIGABRT, SIG_DFL);
>
> complete(&ctx->setup_done);
> - ctx->exec_err = kernel_execve(ctx->executable, argv, NULL);
> + ctx->exec_err = kernel_execve(kbasename(kunit_uapi_preinit.path), argv, NULL);
> if (!ctx->exec_err)
> return 0;
> do_exit(0);
> @@ -255,7 +257,10 @@ static int kunit_uapi_run_executable(struct kunit *test,
> if (IS_ERR(mnt))
> return PTR_ERR(mnt);
>
> - err = kunit_uapi_write_executable(mnt, executable);
> + err = kunit_uapi_write_executable(mnt, &kunit_uapi_preinit);
> +
> + if (!err)
> + err = kunit_uapi_write_executable(mnt, executable);
>
> if (!err)
> err = kunit_uapi_run_executable_in_mount(test, exe_name, mnt);
> diff --git a/lib/kunit/uapi-preinit.c b/lib/kunit/uapi-preinit.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..81182039965a8c93aebb2d5d76f4113bfef277a6
> --- /dev/null
> +++ b/lib/kunit/uapi-preinit.c
> @@ -0,0 +1,63 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * KUnit Userspace environment setup.
> + *
> + * Copyright (C) 2025, Linutronix GmbH.
> + * Author: Thomas WeiÃ?schuh <thomas.weissschuh@xxxxxxxxxxxxx>
> + *
> + * This is *userspace* code.
> + */
> +
> +#include <sys/mount.h>
> +#include <sys/stat.h>
> +
> +#include "../../tools/testing/selftests/kselftest.h"
> +
> +static int setup_api_mount(const char *target, const char *fstype)
> +{
> + int ret;
> +
> + ret = mkdir(target, 0755);
> + if (ret && errno != EEXIST)
> + return -errno;
> +
> + ret = mount("none", target, fstype, 0, NULL);
> + if (ret && errno != EBUSY)
> + return -errno;
> +
> + return 0;
> +}
> +
> +static void exit_failure(const char *stage, int err)
> +{
> + /* If preinit fails synthesize a failed test report. */
> + ksft_print_header();
> + ksft_set_plan(1);
> + ksft_test_result_fail("Failed during test setup: %s: %s\n", stage, strerror(-err));
Positive error values are passed to strerror() without the - sign in userspace.
Probably - needs to be removed from strerror() here.
> + ksft_finished();
> +}
> +
> +int main(int argc, char **argv, char **envp)
> +{
> + int ret;
> +
> + ret = setup_api_mount("/proc", "proc");
> + if (ret)
> + exit_failure("mount /proc", ret);
> +
> + ret = setup_api_mount("/sys", "sysfs");
> + if (ret)
> + exit_failure("mount /sys", ret);
> +
> + if (IS_ENABLED(CONFIG_DEVTMPFS)) {
> + ret = setup_api_mount("/dev", "devtmpfs");
> + if (ret)
> + exit_failure("mount /dev", ret);
> + }
> +
> + ret = execve(argv[0], argv, envp);
> + if (ret)
> + exit_failure("execve", ret);
> +
> + return 0;
> +}
>
