[PATCH v6 2/2] selftests: add tests for clone3()

Adrian Reber
2019-08-12T20:10:25Z

This tests clone3() with and without set_tid to see if all desired PIDs
are working as expected. The test tries to clone3() with a set_tid of
-1, 1, pid_max, a PID which is already in use and an unused PID. The
same tests are also running in PID namespace.

In addition the clone3 test (without set_tid) tries to call clone3()
with different sizes of clone_args.

Signed-off-by: Adrian Reber <areber@redhat.com>
---
tools/testing/selftests/clone3/.gitignore | 2 +
tools/testing/selftests/clone3/Makefile | 11 +
tools/testing/selftests/clone3/clone3.c | 231 ++++++++++++++++++
.../testing/selftests/clone3/clone3_set_tid.c | 161 ++++++++++++
4 files changed, 405 insertions(+)
create mode 100644 tools/testing/selftests/clone3/.gitignore
create mode 100644 tools/testing/selftests/clone3/Makefile
create mode 100644 tools/testing/selftests/clone3/clone3.c
create mode 100644 tools/testing/selftests/clone3/clone3_set_tid.c

diff --git a/tools/testing/selftests/clone3/.gitignore b/tools/testing/selftests/clone3/.gitignore
new file mode 100644
index 000000000000..c63c64a78ddf
--- /dev/null
+++ b/tools/testing/selftests/clone3/.gitignore
@@ -0,0 +1,2 @@
+clone3_set_tid
+clone3
diff --git a/tools/testing/selftests/clone3/Makefile b/tools/testing/selftests/clone3/Makefile
new file mode 100644
index 000000000000..4efcf45b995b
--- /dev/null
+++ b/tools/testing/selftests/clone3/Makefile
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0
+uname_M := $(shell uname -m 2>/dev/null || echo not)
+ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/i386/)
+
+CFLAGS += -I../../../../usr/include/
+
+ifeq ($(ARCH),x86_64)
+ TEST_GEN_PROGS := clone3 clone3_set_tid
+endif
+
+include ../lib.mk
diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c
new file mode 100644
index 000000000000..a0f1989f8b1b
--- /dev/null
+++ b/tools/testing/selftests/clone3/clone3.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* Based on Christian Brauner's clone3() example */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <sched.h>
+
+#include "../kselftest.h"
+
+/*
+ * Different sizes of struct clone_args
+ */
+#define CLONE3_ARGS_SIZE_V0 64
+/* V1 includes set_tid */
+#define CLONE3_ARGS_SIZE_V1 72
+
+#define CLONE3_ARGS_NO_TEST 0
+#define CLONE3_ARGS_ALL_0 1
+#define CLONE3_ARGS_ALL_1 2
+
+static pid_t raw_clone(struct clone_args *args, size_t size)
+{
+ return syscall(__NR_clone3, args, size);
+}
+
+static int call_clone3(int flags, size_t size, int test_mode)
+{
+ struct clone_args args = {0};
+ pid_t ppid = -1;
+ pid_t pid = -1;
+ int status;
+
+ args.flags = flags;
+ args.exit_signal = SIGCHLD;
+
+ if (size == 0)
+ size = sizeof(struct clone_args);
+
+ if (test_mode == CLONE3_ARGS_ALL_0) {
+ args.flags = 0;
+ args.pidfd = 0;
+ args.child_tid = 0;
+ args.parent_tid = 0;
+ args.exit_signal = 0;
+ args.stack = 0;
+ args. stack_size = 0;
+ args.tls = 0;
+ args.set_tid = 0;
+ } else if (test_mode == CLONE3_ARGS_ALL_1) {
+ args.flags = 1;
+ args.pidfd = 1;
+ args.child_tid = 1;
+ args.parent_tid = 1;
+ args.exit_signal = 1;
+ args.stack = 1;
+ args. stack_size = 1;
+ args.tls = 1;
+ args.set_tid = 1;
+ }
+
+ pid = raw_clone(&args, size);
+ if (pid < 0) {
+ ksft_print_msg("%s - Failed to create new process\n",
+ strerror(errno));
+ return -errno;
+ }
+
+ if (pid == 0) {
+ ksft_print_msg("I am the child, my PID is %d\n", getpid());
+ _exit(EXIT_SUCCESS);
+ }
+
+ ppid = getpid();
+ ksft_print_msg("I am the parent (%d). My child's pid is %d\n",
+ ppid, pid);
+
+ (void)wait(&status);
+ if (WEXITSTATUS(status))
+ return WEXITSTATUS(status);
+
+ return 0;
+}
+
+static int test_clone3(int flags, size_t size, int expected, int test_mode)
+{
+ int ret;
+
+ ksft_print_msg("[%d] Trying clone3() with flags 0x%x (size %d)\n",
+ getpid(), flags, size);
+ ret = call_clone3(flags, size, test_mode);
+ ksft_print_msg("[%d] clone3() with flags says :%d expected %d\n",
+ getpid(), ret, expected);
+ if (ret != expected)
+ ksft_exit_fail_msg(
+ "[%d] Result (%d) is different than expected (%d)\n",
+ getpid(), ret, expected);
+ ksft_test_result_pass("[%d] Result (%d) matches expectation (%d)\n",
+ getpid(), ret, expected);
+ return 0;
+}
+int main(int argc, char *argv[])
+{
+ int ret = -1;
+ pid_t pid;
+
+ ksft_print_header();
+ ksft_set_plan(16);
+
+ /* Just a simple clone3() should return 0.*/
+ if (test_clone3(0, 0, 0, CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ /* Do a clone3() in a new PID NS.*/
+ if (test_clone3(CLONE_NEWPID, 0, 0, CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ /* Do a clone3() with CLONE3_ARGS_SIZE_V0. */
+ if (test_clone3(0, CLONE3_ARGS_SIZE_V0, 0, CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ /* Do a clone3() with CLONE3_ARGS_SIZE_V1. */
+ if (test_clone3(0, CLONE3_ARGS_SIZE_V0, 0, CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ /* Do a clone3() with CLONE3_ARGS_SIZE_V0 - 8 */
+ if (test_clone3(0, CLONE3_ARGS_SIZE_V0 - 8, -EINVAL,
+ CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ /* Do a clone3() with sizeof(struct clone_args) + 8 */
+ if (test_clone3(0, sizeof(struct clone_args) + 8, -E2BIG,
+ CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ /* Do a clone3() with all members set to 1 */
+ if (test_clone3(0, CLONE3_ARGS_SIZE_V0, -EINVAL, CLONE3_ARGS_ALL_1))
+ goto on_error;
+ /*
+ * Do a clone3() with sizeof(struct clone_args) + 8
+ * and all members set to 0.
+ */
+ if (test_clone3(0, sizeof(struct clone_args) + 8, -E2BIG,
+ CLONE3_ARGS_ALL_0))
+ goto on_error;
+ /*
+ * Do a clone3() with sizeof(struct clone_args) + 8
+ * and all members set to 0.
+ */
+ if (test_clone3(0, sizeof(struct clone_args) + 8, -E2BIG,
+ CLONE3_ARGS_ALL_1))
+ goto on_error;
+ /* Do a clone3() with > page size */
+ if (test_clone3(0, getpagesize() + 8, -E2BIG, CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ /* Do a clone3() with CLONE3_ARGS_SIZE_V0 in a new PID NS. */
+ if (test_clone3(CLONE_NEWPID, CLONE3_ARGS_SIZE_V0, 0,
+ CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ /* Do a clone3() with CLONE3_ARGS_SIZE_V1 in a new PID NS. */
+ if (test_clone3(CLONE_NEWPID, CLONE3_ARGS_SIZE_V0, 0,
+ CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ /* Do a clone3() with CLONE3_ARGS_SIZE_V0 - 8 in a new PID NS */
+ if (test_clone3(CLONE_NEWPID, CLONE3_ARGS_SIZE_V0 - 8, -EINVAL,
+ CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ /* Do a clone3() with sizeof(struct clone_args) + 8 in a new PID NS */
+ if (test_clone3(CLONE_NEWPID, sizeof(struct clone_args) + 8, -E2BIG,
+ CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ /* Do a clone3() with > page size in a new PID NS */
+ if (test_clone3(CLONE_NEWPID, getpagesize() + 8, -E2BIG,
+ CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ ksft_print_msg("First unshare\n");
+ if (unshare(CLONE_NEWPID))
+ goto on_error;
+ /*
+ * Before clone3()ing in a new PID NS with
+ * CLONE_NEWPID a fork() is necessary.
+ */
+ if (test_clone3(CLONE_NEWPID, 0, -EINVAL, CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ pid = fork();
+ if (pid < 0) {
+ ksft_print_msg("First fork() failed\n");
+ goto on_error;
+ }
+ if (pid > 0) {
+ (void)wait(NULL);
+ goto parent_out;
+ }
+ ksft_set_plan(19);
+ if (test_clone3(CLONE_NEWPID, 0, 0, CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ if (test_clone3(0, 0, 0, CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ ksft_print_msg("Second unshare\n");
+ if (unshare(CLONE_NEWPID))
+ goto on_error;
+ /*
+ * Before clone3()ing in a new PID NS with
+ * CLONE_NEWPID a fork() is necessary.
+ */
+ if (test_clone3(CLONE_NEWPID, 0, -EINVAL, CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ pid = fork();
+ if (pid < 0) {
+ ksft_print_msg("Second fork() failed\n");
+ goto on_error;
+ }
+ if (pid > 0) {
+ (void)wait(NULL);
+ goto parent_out;
+ }
+ ksft_set_plan(21);
+ if (test_clone3(CLONE_NEWPID, 0, 0, CLONE3_ARGS_NO_TEST))
+ goto on_error;
+ if (test_clone3(0, 0, 0, CLONE3_ARGS_NO_TEST))
+ goto on_error;
+
+parent_out:
+ ret = 0;
+on_error:
+
+ return !ret ? ksft_exit_pass() : ksft_exit_fail();
+}
diff --git a/tools/testing/selftests/clone3/clone3_set_tid.c b/tools/testing/selftests/clone3/clone3_set_tid.c
new file mode 100644
index 000000000000..f5012e84dcb3
--- /dev/null
+++ b/tools/testing/selftests/clone3/clone3_set_tid.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/* Based on Christian Brauner's clone3() example */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <sched.h>
+
+#include "../kselftest.h"
+
+static pid_t raw_clone(struct clone_args *args)
+{
+ return syscall(__NR_clone3, args, sizeof(struct clone_args));
+}
+
+static int call_clone3_set_tid(int set_tid, int flags)
+{
+ struct clone_args args = {0};
+ pid_t ppid = -1;
+ pid_t pid = -1;
+ int status;
+
+ args.flags = flags;
+ args.exit_signal = SIGCHLD;
+ args.set_tid = set_tid;
+
+ pid = raw_clone(&args);
+ if (pid < 0) {
+ ksft_print_msg("%s - Failed to create new process\n",
+ strerror(errno));
+ return -errno;
+ }
+
+ if (pid == 0) {
+ ksft_print_msg("I am the child, my PID is %d (expected %d)\n",
+ getpid(), set_tid);
+ if (set_tid != getpid())
+ _exit(EXIT_FAILURE);
+ _exit(EXIT_SUCCESS);
+ }
+
+ ppid = getpid();
+ ksft_print_msg("I am the parent (%d). My child's pid is %d\n",
+ ppid, pid);
+
+ (void)wait(&status);
+ if (WEXITSTATUS(status))
+ return WEXITSTATUS(status);
+
+ return 0;
+}
+
+static int test_clone3_set_tid(int set_tid, int flags, int expected)
+{
+ int ret;
+
+ ksft_print_msg(
+ "[%d] Trying clone3() with CLONE_SET_TID to %d and 0x%x\n",
+ getpid(), set_tid, flags);
+ ret = call_clone3_set_tid(set_tid, flags);
+ ksft_print_msg(
+ "[%d] clone3() with CLONE_SET_TID %d says :%d - expected %d\n",
+ getpid(), set_tid, ret, expected);
+ if (ret != expected)
+ ksft_exit_fail_msg(
+ "[%d] Result (%d) is different than expected (%d)\n",
+ getpid(), ret, expected);
+ ksft_test_result_pass("[%d] Result (%d) matches expectation (%d)\n",
+ getpid(), ret, expected);
+ return 0;
+}
+int main(int argc, char *argv[])
+{
+ FILE *f;
+ int pid_max = 0;
+ pid_t pid;
+ pid_t ns_pid;
+ int ret = -1;
+
+ ksft_print_header();
+ ksft_set_plan(13);
+
+ f = fopen("/proc/sys/kernel/pid_max", "r");
+ if (f == NULL)
+ ksft_exit_fail_msg(
+ "%s - Could not open /proc/sys/kernel/pid_max\n",
+ strerror(errno));
+ fscanf(f, "%d", &pid_max);
+ fclose(f);
+ ksft_print_msg("/proc/sys/kernel/pid_max %d\n", pid_max);
+
+ /* First try with an invalid PID */
+ if (test_clone3_set_tid(-1, 0, -EINVAL))
+ goto on_error;
+ if (test_clone3_set_tid(-1, CLONE_NEWPID, -EINVAL))
+ goto on_error;
+ /* Then with PID 1 */
+ if (test_clone3_set_tid(1, 0, -EEXIST))
+ goto on_error;
+ /* PID 1 should not fail in a PID namespace */
+ if (test_clone3_set_tid(1, CLONE_NEWPID, 0))
+ goto on_error;
+ /* pid_max should fail everywhere */
+ if (test_clone3_set_tid(pid_max, 0, -EINVAL))
+ goto on_error;
+ if (test_clone3_set_tid(pid_max, CLONE_NEWPID, -EINVAL))
+ goto on_error;
+ /* Find the current active PID */
+ pid = fork();
+ if (pid == 0) {
+ ksft_print_msg("Child has PID %d\n", getpid());
+ sleep(1);
+ _exit(EXIT_SUCCESS);
+ }
+ /* Try to create a process with that PID should fail */
+ if (test_clone3_set_tid(pid, 0, -EEXIST))
+ goto on_error;
+ (void)wait(NULL);
+ /* After the child has finished, try again with the same PID */
+ if (test_clone3_set_tid(pid, 0, 0))
+ goto on_error;
+ /* This should fail as there is no PID 1 in that namespace */
+ if (test_clone3_set_tid(pid, CLONE_NEWPID, -EINVAL))
+ goto on_error;
+ unshare(CLONE_NEWPID);
+ if (test_clone3_set_tid(10, 0, -EINVAL))
+ goto on_error;
+ /* Let's create a PID 1 */
+ ns_pid = fork();
+ if (ns_pid == 0) {
+ ksft_print_msg("Child in PID namespace has PID %d\n", getpid());
+ sleep(1);
+ _exit(EXIT_SUCCESS);
+ }
+ /*
+ * Now, after the unshare() it should be possible to create a process
+ * with another ID than 1 in the PID namespace.
+ */
+ if (test_clone3_set_tid(2, 0, 0))
+ goto on_error;
+ /* Use a different PID in this namespace. */
+ if (test_clone3_set_tid(2222, 0, 0))
+ goto on_error;
+ if (test_clone3_set_tid(1, 0, -EEXIST))
+ goto on_error;
+ (void)wait(NULL);
+
+ ret = 0;
+on_error:
+
+ return !ret ? ksft_exit_pass() : ksft_exit_fail();
+}
--
2.21.0