selftests/timens: Add Time Namespace test for supported clocks
authorDmitry Safonov <dima@arista.com>
Tue, 12 Nov 2019 01:27:17 +0000 (01:27 +0000)
committerThomas Gleixner <tglx@linutronix.de>
Tue, 14 Jan 2020 11:21:00 +0000 (12:21 +0100)
A test to check that all supported clocks work on host and inside
a new time namespace. Use both ways to get time: through VDSO and
by entering the kernel with implicit syscall.

Introduce a new timens directory in selftests framework for
the next timens tests.

Output on success:
 1..10
 ok 1 Passed for CLOCK_BOOTTIME (syscall)
 ok 2 Passed for CLOCK_BOOTTIME (vdso)
 ok 3 Passed for CLOCK_BOOTTIME_ALARM (syscall)
 ok 4 Passed for CLOCK_BOOTTIME_ALARM (vdso)
 ok 5 Passed for CLOCK_MONOTONIC (syscall)
 ok 6 Passed for CLOCK_MONOTONIC (vdso)
 ok 7 Passed for CLOCK_MONOTONIC_COARSE (syscall)
 ok 8 Passed for CLOCK_MONOTONIC_COARSE (vdso)
 ok 9 Passed for CLOCK_MONOTONIC_RAW (syscall)
 ok 10 Passed for CLOCK_MONOTONIC_RAW (vdso)
 # Pass 10 Fail 0 Xfail 0 Xpass 0 Skip 0 Error 0

Output with lack of permissions:
 1..10
 not ok 1 # SKIP need to run as root

Output without support of time namespaces:
 1..10
 not ok 1 # SKIP Time namespaces are not supported

Co-developed-by: Andrei Vagin <avagin@openvz.org>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-29-dima@arista.com
tools/testing/selftests/Makefile
tools/testing/selftests/timens/.gitignore [new file with mode: 0644]
tools/testing/selftests/timens/Makefile [new file with mode: 0644]
tools/testing/selftests/timens/config [new file with mode: 0644]
tools/testing/selftests/timens/log.h [new file with mode: 0644]
tools/testing/selftests/timens/timens.c [new file with mode: 0644]
tools/testing/selftests/timens/timens.h [new file with mode: 0644]

index b001c60..c4939a2 100644 (file)
@@ -50,6 +50,7 @@ TARGETS += splice
 TARGETS += static_keys
 TARGETS += sync
 TARGETS += sysctl
+TARGETS += timens
 ifneq (1, $(quicktest))
 TARGETS += timers
 endif
diff --git a/tools/testing/selftests/timens/.gitignore b/tools/testing/selftests/timens/.gitignore
new file mode 100644 (file)
index 0000000..27a6932
--- /dev/null
@@ -0,0 +1 @@
+timens
diff --git a/tools/testing/selftests/timens/Makefile b/tools/testing/selftests/timens/Makefile
new file mode 100644 (file)
index 0000000..49a9dcc
--- /dev/null
@@ -0,0 +1,6 @@
+TEST_GEN_PROGS := timens
+
+CFLAGS := -Wall -Werror
+LDFLAGS := -lrt
+
+include ../lib.mk
diff --git a/tools/testing/selftests/timens/config b/tools/testing/selftests/timens/config
new file mode 100644 (file)
index 0000000..4480620
--- /dev/null
@@ -0,0 +1 @@
+CONFIG_TIME_NS=y
diff --git a/tools/testing/selftests/timens/log.h b/tools/testing/selftests/timens/log.h
new file mode 100644 (file)
index 0000000..db64df2
--- /dev/null
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __SELFTEST_TIMENS_LOG_H__
+#define __SELFTEST_TIMENS_LOG_H__
+
+#define pr_msg(fmt, lvl, ...)                                          \
+       ksft_print_msg("[%s] (%s:%d)\t" fmt "\n",                       \
+                       lvl, __FILE__, __LINE__, ##__VA_ARGS__)
+
+#define pr_p(func, fmt, ...)   func(fmt ": %m", ##__VA_ARGS__)
+
+#define pr_err(fmt, ...)                                               \
+       ({                                                              \
+               ksft_test_result_error(fmt "\n", ##__VA_ARGS__);                \
+               -1;                                                     \
+       })
+
+#define pr_fail(fmt, ...)                                      \
+       ({                                                      \
+               ksft_test_result_fail(fmt, ##__VA_ARGS__);      \
+               -1;                                             \
+       })
+
+#define pr_perror(fmt, ...)    pr_p(pr_err, fmt, ##__VA_ARGS__)
+
+#endif
diff --git a/tools/testing/selftests/timens/timens.c b/tools/testing/selftests/timens/timens.c
new file mode 100644 (file)
index 0000000..559d26e
--- /dev/null
@@ -0,0 +1,190 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+#include <time.h>
+#include <string.h>
+
+#include "log.h"
+#include "timens.h"
+
+/*
+ * Test shouldn't be run for a day, so add 10 days to child
+ * time and check parent's time to be in the same day.
+ */
+#define DAY_IN_SEC                     (60*60*24)
+#define TEN_DAYS_IN_SEC                        (10*DAY_IN_SEC)
+
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+
+struct test_clock {
+       clockid_t id;
+       char *name;
+       /*
+        * off_id is -1 if a clock has own offset, or it contains an index
+        * which contains a right offset of this clock.
+        */
+       int off_id;
+       time_t offset;
+};
+
+#define ct(clock, off_id)      { clock, #clock, off_id }
+static struct test_clock clocks[] = {
+       ct(CLOCK_BOOTTIME, -1),
+       ct(CLOCK_BOOTTIME_ALARM, 1),
+       ct(CLOCK_MONOTONIC, -1),
+       ct(CLOCK_MONOTONIC_COARSE, 1),
+       ct(CLOCK_MONOTONIC_RAW, 1),
+};
+#undef ct
+
+static int child_ns, parent_ns = -1;
+
+static int switch_ns(int fd)
+{
+       if (setns(fd, CLONE_NEWTIME)) {
+               pr_perror("setns()");
+               return -1;
+       }
+
+       return 0;
+}
+
+static int init_namespaces(void)
+{
+       char path[] = "/proc/self/ns/time_for_children";
+       struct stat st1, st2;
+
+       if (parent_ns == -1) {
+               parent_ns = open(path, O_RDONLY);
+               if (parent_ns <= 0)
+                       return pr_perror("Unable to open %s", path);
+       }
+
+       if (fstat(parent_ns, &st1))
+               return pr_perror("Unable to stat the parent timens");
+
+       if (unshare_timens())
+               return  -1;
+
+       child_ns = open(path, O_RDONLY);
+       if (child_ns <= 0)
+               return pr_perror("Unable to open %s", path);
+
+       if (fstat(child_ns, &st2))
+               return pr_perror("Unable to stat the timens");
+
+       if (st1.st_ino == st2.st_ino)
+               return pr_perror("The same child_ns after CLONE_NEWTIME");
+
+       return 0;
+}
+
+static int test_gettime(clockid_t clock_index, bool raw_syscall, time_t offset)
+{
+       struct timespec child_ts_new, parent_ts_old, cur_ts;
+       char *entry = raw_syscall ? "syscall" : "vdso";
+       double precision = 0.0;
+
+       if (check_skip(clocks[clock_index].id))
+               return 0;
+
+       switch (clocks[clock_index].id) {
+       case CLOCK_MONOTONIC_COARSE:
+       case CLOCK_MONOTONIC_RAW:
+               precision = -2.0;
+               break;
+       }
+
+       if (switch_ns(parent_ns))
+               return pr_err("switch_ns(%d)", child_ns);
+
+       if (_gettime(clocks[clock_index].id, &parent_ts_old, raw_syscall))
+               return -1;
+
+       child_ts_new.tv_nsec = parent_ts_old.tv_nsec;
+       child_ts_new.tv_sec = parent_ts_old.tv_sec + offset;
+
+       if (switch_ns(child_ns))
+               return pr_err("switch_ns(%d)", child_ns);
+
+       if (_gettime(clocks[clock_index].id, &cur_ts, raw_syscall))
+               return -1;
+
+       if (difftime(cur_ts.tv_sec, child_ts_new.tv_sec) < precision) {
+               ksft_test_result_fail(
+                       "Child's %s (%s) time has not changed: %lu -> %lu [%lu]\n",
+                       clocks[clock_index].name, entry, parent_ts_old.tv_sec,
+                       child_ts_new.tv_sec, cur_ts.tv_sec);
+               return -1;
+       }
+
+       if (switch_ns(parent_ns))
+               return pr_err("switch_ns(%d)", parent_ns);
+
+       if (_gettime(clocks[clock_index].id, &cur_ts, raw_syscall))
+               return -1;
+
+       if (difftime(cur_ts.tv_sec, parent_ts_old.tv_sec) > DAY_IN_SEC) {
+               ksft_test_result_fail(
+                       "Parent's %s (%s) time has changed: %lu -> %lu [%lu]\n",
+                       clocks[clock_index].name, entry, parent_ts_old.tv_sec,
+                       child_ts_new.tv_sec, cur_ts.tv_sec);
+               /* Let's play nice and put it closer to original */
+               clock_settime(clocks[clock_index].id, &cur_ts);
+               return -1;
+       }
+
+       ksft_test_result_pass("Passed for %s (%s)\n",
+                               clocks[clock_index].name, entry);
+       return 0;
+}
+
+int main(int argc, char *argv[])
+{
+       unsigned int i;
+       time_t offset;
+       int ret = 0;
+
+       nscheck();
+
+       check_config_posix_timers();
+
+       ksft_set_plan(ARRAY_SIZE(clocks) * 2);
+
+       if (init_namespaces())
+               return 1;
+
+       /* Offsets have to be set before tasks enter the namespace. */
+       for (i = 0; i < ARRAY_SIZE(clocks); i++) {
+               if (clocks[i].off_id != -1)
+                       continue;
+               offset = TEN_DAYS_IN_SEC + i * 1000;
+               clocks[i].offset = offset;
+               if (_settime(clocks[i].id, offset))
+                       return 1;
+       }
+
+       for (i = 0; i < ARRAY_SIZE(clocks); i++) {
+               if (clocks[i].off_id != -1)
+                       offset = clocks[clocks[i].off_id].offset;
+               else
+                       offset = clocks[i].offset;
+               ret |= test_gettime(i, true, offset);
+               ret |= test_gettime(i, false, offset);
+       }
+
+       if (ret)
+               ksft_exit_fail();
+
+       ksft_exit_pass();
+       return !!ret;
+}
diff --git a/tools/testing/selftests/timens/timens.h b/tools/testing/selftests/timens/timens.h
new file mode 100644 (file)
index 0000000..e09e7e3
--- /dev/null
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __TIMENS_H__
+#define __TIMENS_H__
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+#include "../kselftest.h"
+
+#ifndef CLONE_NEWTIME
+# define CLONE_NEWTIME 0x00000080
+#endif
+
+static int config_posix_timers = true;
+
+static inline void check_config_posix_timers(void)
+{
+       if (timer_create(-1, 0, 0) == -1 && errno == ENOSYS)
+               config_posix_timers = false;
+}
+
+static inline bool check_skip(int clockid)
+{
+       if (config_posix_timers)
+               return false;
+
+       switch (clockid) {
+       /* Only these clocks are supported without CONFIG_POSIX_TIMERS. */
+       case CLOCK_BOOTTIME:
+       case CLOCK_MONOTONIC:
+       case CLOCK_REALTIME:
+               return false;
+       default:
+               ksft_test_result_skip("Posix Clocks & timers are not supported\n");
+               return true;
+       }
+
+       return false;
+}
+
+static inline int unshare_timens(void)
+{
+       if (unshare(CLONE_NEWTIME)) {
+               if (errno == EPERM)
+                       ksft_exit_skip("need to run as root\n");
+               return pr_perror("Can't unshare() timens");
+       }
+       return 0;
+}
+
+static inline int _settime(clockid_t clk_id, time_t offset)
+{
+       int fd, len;
+       char buf[4096];
+
+       if (clk_id == CLOCK_MONOTONIC_COARSE || clk_id == CLOCK_MONOTONIC_RAW)
+               clk_id = CLOCK_MONOTONIC;
+
+       len = snprintf(buf, sizeof(buf), "%d %ld 0", clk_id, offset);
+
+       fd = open("/proc/self/timens_offsets", O_WRONLY);
+       if (fd < 0)
+               return pr_perror("/proc/self/timens_offsets");
+
+       if (write(fd, buf, len) != len)
+               return pr_perror("/proc/self/timens_offsets");
+
+       close(fd);
+
+       return 0;
+}
+
+static inline int _gettime(clockid_t clk_id, struct timespec *res, bool raw_syscall)
+{
+       int err;
+
+       if (!raw_syscall) {
+               if (clock_gettime(clk_id, res)) {
+                       pr_perror("clock_gettime(%d)", (int)clk_id);
+                       return -1;
+               }
+               return 0;
+       }
+
+       err = syscall(SYS_clock_gettime, clk_id, res);
+       if (err)
+               pr_perror("syscall(SYS_clock_gettime(%d))", (int)clk_id);
+
+       return err;
+}
+
+static inline void nscheck(void)
+{
+       if (access("/proc/self/ns/time", F_OK) < 0)
+               ksft_exit_skip("Time namespaces are not supported\n");
+}
+
+#endif