[PATCH v1 2/2] tests: add close_range() tests

Christian Brauner
2019-05-22T15:52:59Z

This adds basic tests for the new close_range() syscall.
- test that no invalid flags can be passed
- test that a range of file descriptors is correctly closed
- test that a range of file descriptors is correctly closed if there there
are already closed file descriptors in the range
- test that max_fd is correctly capped to the current fdtable maximum

Signed-off-by: Christian Brauner <christian@brauner.io>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jann Horn <jannh@google.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Dmitry V. Levin <ldv@altlinux.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: linux-api@vger.kernel.org
---
v1: unchanged
---
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/core/.gitignore | 1 +
tools/testing/selftests/core/Makefile | 6 +
.../testing/selftests/core/close_range_test.c | 128 ++++++++++++++++++
4 files changed, 136 insertions(+)
create mode 100644 tools/testing/selftests/core/.gitignore
create mode 100644 tools/testing/selftests/core/Makefile
create mode 100644 tools/testing/selftests/core/close_range_test.c

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 9781ca79794a..06e57fabbff9 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -4,6 +4,7 @@ TARGETS += bpf
TARGETS += breakpoints
TARGETS += capabilities
TARGETS += cgroup
+TARGETS += core
TARGETS += cpufreq
TARGETS += cpu-hotplug
TARGETS += drivers/dma-buf
diff --git a/tools/testing/selftests/core/.gitignore b/tools/testing/selftests/core/.gitignore
new file mode 100644
index 000000000000..6e6712ce5817
--- /dev/null
+++ b/tools/testing/selftests/core/.gitignore
@@ -0,0 +1 @@
+close_range_test
diff --git a/tools/testing/selftests/core/Makefile b/tools/testing/selftests/core/Makefile
new file mode 100644
index 000000000000..de3ae68aa345
--- /dev/null
+++ b/tools/testing/selftests/core/Makefile
@@ -0,0 +1,6 @@
+CFLAGS += -g -I../../../../usr/include/ -I../../../../include
+
+TEST_GEN_PROGS := close_range_test
+
+include ../lib.mk
+
diff --git a/tools/testing/selftests/core/close_range_test.c b/tools/testing/selftests/core/close_range_test.c
new file mode 100644
index 000000000000..ab10cd205ab9
--- /dev/null
+++ b/tools/testing/selftests/core/close_range_test.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/kernel.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <unistd.h>
+
+#include "../kselftest.h"
+
+static inline int sys_close_range(unsigned int fd, unsigned int max_fd,
+ unsigned int flags)
+{
+ return syscall(__NR_close_range, fd, max_fd, flags);
+}
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
+int main(int argc, char **argv)
+{
+ const char *test_name = "close_range";
+ int i, ret;
+ int open_fds[100];
+ int fd_max, fd_mid, fd_min;
+
+ ksft_set_plan(7);
+
+ for (i = 0; i < ARRAY_SIZE(open_fds); i++) {
+ int fd;
+
+ fd = open("/dev/null", O_RDONLY | O_CLOEXEC);
+ if (fd < 0) {
+ if (errno = ENOENT)
+ ksft_exit_skip(
+ "%s test: skipping test since /dev/null does not exist\n",
+ test_name);
+
+ ksft_exit_fail_msg(
+ "%s test: %s - failed to open /dev/null\n",
+ strerror(errno), test_name);
+ }
+
+ open_fds[i] = fd;
+ }
+
+ fd_min = open_fds[0];
+ fd_max = open_fds[99];
+
+ ret = sys_close_range(fd_min, fd_max, 1);
+ if (!ret)
+ ksft_exit_fail_msg(
+ "%s test: managed to pass invalid flag value\n",
+ test_name);
+ ksft_test_result_pass("do not allow invalid flag values for close_range()\n");
+
+ fd_mid = open_fds[50];
+ ret = sys_close_range(fd_min, fd_mid, 0);
+ if (ret < 0)
+ ksft_exit_fail_msg(
+ "%s test: Failed to close range of file descriptors from 4 to 50\n",
+ test_name);
+ ksft_test_result_pass("close_range() from %d to %d\n", fd_min, fd_mid);
+
+ for (i = 0; i <= 50; i++) {
+ ret = fcntl(open_fds[i], F_GETFL);
+ if (ret >= 0)
+ ksft_exit_fail_msg(
+ "%s test: Failed to close range of file descriptors from 4 to 50\n",
+ test_name);
+ }
+ ksft_test_result_pass("fcntl() verify closed range from %d to %d\n", fd_min, fd_mid);
+
+ /* create a couple of gaps */
+ close(57);
+ close(78);
+ close(81);
+ close(82);
+ close(84);
+ close(90);
+
+ fd_mid = open_fds[51];
+ /* Choose slightly lower limit and leave some fds for a later test */
+ fd_max = open_fds[92];
+ ret = sys_close_range(fd_mid, fd_max, 0);
+ if (ret < 0)
+ ksft_exit_fail_msg(
+ "%s test: Failed to close range of file descriptors from 51 to 100\n",
+ test_name);
+ ksft_test_result_pass("close_range() from %d to %d\n", fd_mid, fd_max);
+
+ for (i = 51; i <= 92; i++) {
+ ret = fcntl(open_fds[i], F_GETFL);
+ if (ret >= 0)
+ ksft_exit_fail_msg(
+ "%s test: Failed to close range of file descriptors from 51 to 100\n",
+ test_name);
+ }
+ ksft_test_result_pass("fcntl() verify closed range from %d to %d\n", fd_mid, fd_max);
+
+ fd_mid = open_fds[93];
+ fd_max = open_fds[99];
+ /* test that the kernel caps and still closes all fds */
+ ret = sys_close_range(fd_mid, UINT_MAX, 0);
+ if (ret < 0)
+ ksft_exit_fail_msg(
+ "%s test: Failed to close range of file descriptors from 51 to 100\n",
+ test_name);
+ ksft_test_result_pass("close_range() from %d to %d\n", fd_mid, fd_max);
+
+ for (i = 93; i < 100; i++) {
+ ret = fcntl(open_fds[i], F_GETFL);
+ if (ret >= 0)
+ ksft_exit_fail_msg(
+ "%s test: Failed to close range of file descriptors from 51 to 100\n",
+ test_name);
+ }
+ ksft_test_result_pass("fcntl() verify closed range from %d to %d\n", fd_mid, fd_max);
+
+ return ksft_exit_pass();
+}
--
2.21.0