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tests: add pidfd_open() tests 

This adds testing for the new pidfd_open() syscalls. Specifically, we test:
- that no invalid flags can be passed to pidfd_open()
- that no invalid pid can be passed to pidfd_open()
- that a pidfd can be retrieved with pidfd_open()
- that the retrieved pidfd references the correct pid

Signed-off-by: Christian Brauner <christian@brauner.io>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jann Horn <jannh@google.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-api@vger.kernel.org
alistair/sunxi64-5.4-dsi
Christian Brauner 2019-03-23 12:24:21 +01:00
parent 7615d9e178
commit 172bb24a4f
No known key found for this signature in database
GPG Key ID: 8EB056D53EECB12D
5 changed files with 234 additions and 44 deletions
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1
tools/testing/selftests/pidfd/.gitignore vendored
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@ -1 +1,2 @@
pidfd_open_test
pidfd_test

3
tools/testing/selftests/pidfd/Makefile
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@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
CFLAGS += -g -I../../../../usr/include/ -lpthread
TEST_GEN_PROGS := pidfd_test
TEST_GEN_PROGS := pidfd_test pidfd_open_test
include ../lib.mk

57
tools/testing/selftests/pidfd/pidfd.h 100644
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@ -0,0 +1,57 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __PIDFD_H
#define __PIDFD_H
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <sched.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syscall.h>
#include <sys/mount.h>
#include "../kselftest.h"
/*
* The kernel reserves 300 pids via RESERVED_PIDS in kernel/pid.c
* That means, when it wraps around any pid < 300 will be skipped.
* So we need to use a pid > 300 in order to test recycling.
*/
#define PID_RECYCLE 1000
/*
* Define a few custom error codes for the child process to clearly indicate
* what is happening. This way we can tell the difference between a system
* error, a test error, etc.
*/
#define PIDFD_PASS 0
#define PIDFD_FAIL 1
#define PIDFD_ERROR 2
#define PIDFD_SKIP 3
#define PIDFD_XFAIL 4
int wait_for_pid(pid_t pid)
{
int status, ret;
again:
ret = waitpid(pid, &status, 0);
if (ret == -1) {
if (errno == EINTR)
goto again;
return -1;
}
if (!WIFEXITED(status))
return -1;
return WEXITSTATUS(status);
}
#endif /* __PIDFD_H */

169
tools/testing/selftests/pidfd/pidfd_open_test.c 100644
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@ -0,0 +1,169 @@
// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <limits.h>
#include <linux/types.h>
#include <linux/wait.h>
#include <sched.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syscall.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <unistd.h>
#include "pidfd.h"
#include "../kselftest.h"
static inline int sys_pidfd_open(pid_t pid, unsigned int flags)
{
return syscall(__NR_pidfd_open, pid, flags);
}
static int safe_int(const char *numstr, int *converted)
{
char *err = NULL;
long sli;
errno = 0;
sli = strtol(numstr, &err, 0);
if (errno == ERANGE && (sli == LONG_MAX || sli == LONG_MIN))
return -ERANGE;
if (errno != 0 && sli == 0)
return -EINVAL;
if (err == numstr || *err != '\0')
return -EINVAL;
if (sli > INT_MAX || sli < INT_MIN)
return -ERANGE;
*converted = (int)sli;
return 0;
}
static int char_left_gc(const char *buffer, size_t len)
{
size_t i;
for (i = 0; i < len; i++) {
if (buffer[i] == ' ' ||
buffer[i] == '\t')
continue;
return i;
}
return 0;
}
static int char_right_gc(const char *buffer, size_t len)
{
int i;
for (i = len - 1; i >= 0; i--) {
if (buffer[i] == ' ' ||
buffer[i] == '\t' ||
buffer[i] == '\n' ||
buffer[i] == '\0')
continue;
return i + 1;
}
return 0;
}
static char *trim_whitespace_in_place(char *buffer)
{
buffer += char_left_gc(buffer, strlen(buffer));
buffer[char_right_gc(buffer, strlen(buffer))] = '\0';
return buffer;
}
static pid_t get_pid_from_fdinfo_file(int pidfd, const char *key, size_t keylen)
{
int ret;
char path[512];
FILE *f;
size_t n = 0;
pid_t result = -1;
char *line = NULL;
snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd);
f = fopen(path, "re");
if (!f)
return -1;
while (getline(&line, &n, f) != -1) {
char *numstr;
if (strncmp(line, key, keylen))
continue;
numstr = trim_whitespace_in_place(line + 4);
ret = safe_int(numstr, &result);
if (ret < 0)
goto out;
break;
}
out:
free(line);
fclose(f);
return result;
}
int main(int argc, char **argv)
{
int pidfd = -1, ret = 1;
pid_t pid;
ksft_set_plan(3);
pidfd = sys_pidfd_open(-1, 0);
if (pidfd >= 0) {
ksft_print_msg(
"%s - succeeded to open pidfd for invalid pid -1\n",
strerror(errno));
goto on_error;
}
ksft_test_result_pass("do not allow invalid pid test: passed\n");
pidfd = sys_pidfd_open(getpid(), 1);
if (pidfd >= 0) {
ksft_print_msg(
"%s - succeeded to open pidfd with invalid flag value specified\n",
strerror(errno));
goto on_error;
}
ksft_test_result_pass("do not allow invalid flag test: passed\n");
pidfd = sys_pidfd_open(getpid(), 0);
if (pidfd < 0) {
ksft_print_msg("%s - failed to open pidfd\n", strerror(errno));
goto on_error;
}
ksft_test_result_pass("open a new pidfd test: passed\n");
pid = get_pid_from_fdinfo_file(pidfd, "Pid:", sizeof("Pid:") - 1);
ksft_print_msg("pidfd %d refers to process with pid %d\n", pidfd, pid);
ret = 0;
on_error:
if (pidfd >= 0)
close(pidfd);
return !ret ? ksft_exit_pass() : ksft_exit_fail();
}

48
tools/testing/selftests/pidfd/pidfd_test.c
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@ -18,16 +18,18 @@
#include <time.h>
#include <unistd.h>
#include "pidfd.h"
#include "../kselftest.h"
#ifndef __NR_pidfd_send_signal
#define __NR_pidfd_send_signal -1
#endif
#define str(s) _str(s)
#define _str(s) #s
#define CHILD_THREAD_MIN_WAIT 3 /* seconds */
#define MAX_EVENTS 5
#ifndef __NR_pidfd_send_signal
#define __NR_pidfd_send_signal 424
#endif
#ifndef CLONE_PIDFD
#define CLONE_PIDFD 0x00001000
@ -91,28 +93,6 @@ static int test_pidfd_send_signal_simple_success(void)
return 0;
}
static int wait_for_pid(pid_t pid)
{
int status, ret;
again:
ret = waitpid(pid, &status, 0);
if (ret == -1) {
if (errno == EINTR)
goto again;
return -1;
}
if (ret != pid)
goto again;
if (!WIFEXITED(status))
return -1;
return WEXITSTATUS(status);
}
static int test_pidfd_send_signal_exited_fail(void)
{
int pidfd, ret, saved_errno;
@ -157,13 +137,6 @@ static int test_pidfd_send_signal_exited_fail(void)
return 0;
}
/*
* The kernel reserves 300 pids via RESERVED_PIDS in kernel/pid.c
* That means, when it wraps around any pid < 300 will be skipped.
* So we need to use a pid > 300 in order to test recycling.
*/
#define PID_RECYCLE 1000
/*
* Maximum number of cycles we allow. This is equivalent to PID_MAX_DEFAULT.
* If users set a higher limit or we have cycled PIDFD_MAX_DEFAULT number of
@ -172,17 +145,6 @@ static int test_pidfd_send_signal_exited_fail(void)
*/
#define PIDFD_MAX_DEFAULT 0x8000
/*
* Define a few custom error codes for the child process to clearly indicate
* what is happening. This way we can tell the difference between a system
* error, a test error, etc.
*/
#define PIDFD_PASS 0
#define PIDFD_FAIL 1
#define PIDFD_ERROR 2
#define PIDFD_SKIP 3
#define PIDFD_XFAIL 4
static int test_pidfd_send_signal_recycled_pid_fail(void)
{
int i, ret;