selftests/timens: Add Time Namespace test for supported clocks

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
This commit is contained in:
Dmitry Safonov 2019-11-12 01:27:17 +00:00 коммит произвёл Thomas Gleixner
Родитель 04a8682a71
Коммит 61c5767603
7 изменённых файлов: 325 добавлений и 0 удалений

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@ -50,6 +50,7 @@ TARGETS += splice
TARGETS += static_keys
TARGETS += sync
TARGETS += sysctl
TARGETS += timens
ifneq (1, $(quicktest))
TARGETS += timers
endif

1
tools/testing/selftests/timens/.gitignore поставляемый Normal file
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@ -0,0 +1 @@
timens

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@ -0,0 +1,6 @@
TEST_GEN_PROGS := timens
CFLAGS := -Wall -Werror
LDFLAGS := -lrt
include ../lib.mk

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@ -0,0 +1 @@
CONFIG_TIME_NS=y

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@ -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

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@ -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;
}

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@ -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