576 lines
14 KiB
C
576 lines
14 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <linux/types.h>
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#include <pthread.h>
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#include <sched.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syscall.h>
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#include <sys/epoll.h>
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#include <sys/mman.h>
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#include <sys/mount.h>
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#include <sys/wait.h>
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#include <time.h>
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#include <unistd.h>
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#include "pidfd.h"
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#include "../kselftest.h"
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#define str(s) _str(s)
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#define _str(s) #s
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#define CHILD_THREAD_MIN_WAIT 3 /* seconds */
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#define MAX_EVENTS 5
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static bool have_pidfd_send_signal;
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static pid_t pidfd_clone(int flags, int *pidfd, int (*fn)(void *))
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{
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size_t stack_size = 1024;
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char *stack[1024] = { 0 };
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#ifdef __ia64__
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return __clone2(fn, stack, stack_size, flags | SIGCHLD, NULL, pidfd);
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#else
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return clone(fn, stack + stack_size, flags | SIGCHLD, NULL, pidfd);
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#endif
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}
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static int signal_received;
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static void set_signal_received_on_sigusr1(int sig)
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{
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if (sig == SIGUSR1)
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signal_received = 1;
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}
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/*
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* Straightforward test to see whether pidfd_send_signal() works is to send
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* a signal to ourself.
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*/
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static int test_pidfd_send_signal_simple_success(void)
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{
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int pidfd, ret;
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const char *test_name = "pidfd_send_signal send SIGUSR1";
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if (!have_pidfd_send_signal) {
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ksft_test_result_skip(
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"%s test: pidfd_send_signal() syscall not supported\n",
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test_name);
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return 0;
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}
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pidfd = open("/proc/self", O_DIRECTORY | O_CLOEXEC);
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if (pidfd < 0)
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ksft_exit_fail_msg(
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"%s test: Failed to open process file descriptor\n",
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test_name);
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signal(SIGUSR1, set_signal_received_on_sigusr1);
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ret = sys_pidfd_send_signal(pidfd, SIGUSR1, NULL, 0);
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close(pidfd);
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if (ret < 0)
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ksft_exit_fail_msg("%s test: Failed to send signal\n",
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test_name);
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if (signal_received != 1)
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ksft_exit_fail_msg("%s test: Failed to receive signal\n",
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test_name);
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signal_received = 0;
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ksft_test_result_pass("%s test: Sent signal\n", test_name);
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return 0;
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}
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static int test_pidfd_send_signal_exited_fail(void)
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{
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int pidfd, ret, saved_errno;
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char buf[256];
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pid_t pid;
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const char *test_name = "pidfd_send_signal signal exited process";
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if (!have_pidfd_send_signal) {
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ksft_test_result_skip(
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"%s test: pidfd_send_signal() syscall not supported\n",
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test_name);
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return 0;
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}
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pid = fork();
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if (pid < 0)
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ksft_exit_fail_msg("%s test: Failed to create new process\n",
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test_name);
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if (pid == 0)
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_exit(EXIT_SUCCESS);
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snprintf(buf, sizeof(buf), "/proc/%d", pid);
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pidfd = open(buf, O_DIRECTORY | O_CLOEXEC);
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(void)wait_for_pid(pid);
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if (pidfd < 0)
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ksft_exit_fail_msg(
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"%s test: Failed to open process file descriptor\n",
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test_name);
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ret = sys_pidfd_send_signal(pidfd, 0, NULL, 0);
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saved_errno = errno;
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close(pidfd);
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if (ret == 0)
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ksft_exit_fail_msg(
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"%s test: Managed to send signal to process even though it should have failed\n",
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test_name);
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if (saved_errno != ESRCH)
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ksft_exit_fail_msg(
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"%s test: Expected to receive ESRCH as errno value but received %d instead\n",
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test_name, saved_errno);
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ksft_test_result_pass("%s test: Failed to send signal as expected\n",
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test_name);
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return 0;
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}
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/*
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* Maximum number of cycles we allow. This is equivalent to PID_MAX_DEFAULT.
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* If users set a higher limit or we have cycled PIDFD_MAX_DEFAULT number of
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* times then we skip the test to not go into an infinite loop or block for a
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* long time.
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*/
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#define PIDFD_MAX_DEFAULT 0x8000
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static int test_pidfd_send_signal_recycled_pid_fail(void)
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{
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int i, ret;
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pid_t pid1;
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const char *test_name = "pidfd_send_signal signal recycled pid";
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if (!have_pidfd_send_signal) {
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ksft_test_result_skip(
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"%s test: pidfd_send_signal() syscall not supported\n",
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test_name);
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return 0;
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}
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ret = unshare(CLONE_NEWPID);
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if (ret < 0) {
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if (errno == EPERM) {
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ksft_test_result_skip("%s test: Unsharing pid namespace not permitted\n",
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test_name);
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return 0;
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}
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ksft_exit_fail_msg("%s test: Failed to unshare pid namespace\n",
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test_name);
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}
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ret = unshare(CLONE_NEWNS);
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if (ret < 0) {
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if (errno == EPERM) {
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ksft_test_result_skip("%s test: Unsharing mount namespace not permitted\n",
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test_name);
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return 0;
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}
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ksft_exit_fail_msg("%s test: Failed to unshare mount namespace\n",
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test_name);
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}
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ret = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0);
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if (ret < 0)
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ksft_exit_fail_msg("%s test: Failed to remount / private\n",
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test_name);
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/* pid 1 in new pid namespace */
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pid1 = fork();
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if (pid1 < 0)
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ksft_exit_fail_msg("%s test: Failed to create new process\n",
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test_name);
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if (pid1 == 0) {
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char buf[256];
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pid_t pid2;
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int pidfd = -1;
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(void)umount2("/proc", MNT_DETACH);
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ret = mount("proc", "/proc", "proc", 0, NULL);
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if (ret < 0)
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_exit(PIDFD_ERROR);
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/* grab pid PID_RECYCLE */
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for (i = 0; i <= PIDFD_MAX_DEFAULT; i++) {
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pid2 = fork();
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if (pid2 < 0)
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_exit(PIDFD_ERROR);
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if (pid2 == 0)
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_exit(PIDFD_PASS);
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if (pid2 == PID_RECYCLE) {
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snprintf(buf, sizeof(buf), "/proc/%d", pid2);
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ksft_print_msg("pid to recycle is %d\n", pid2);
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pidfd = open(buf, O_DIRECTORY | O_CLOEXEC);
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}
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if (wait_for_pid(pid2))
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_exit(PIDFD_ERROR);
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if (pid2 >= PID_RECYCLE)
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break;
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}
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/*
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* We want to be as predictable as we can so if we haven't been
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* able to grab pid PID_RECYCLE skip the test.
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*/
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if (pid2 != PID_RECYCLE) {
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/* skip test */
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close(pidfd);
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_exit(PIDFD_SKIP);
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}
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if (pidfd < 0)
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_exit(PIDFD_ERROR);
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for (i = 0; i <= PIDFD_MAX_DEFAULT; i++) {
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char c;
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int pipe_fds[2];
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pid_t recycled_pid;
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int child_ret = PIDFD_PASS;
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ret = pipe2(pipe_fds, O_CLOEXEC);
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if (ret < 0)
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_exit(PIDFD_ERROR);
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recycled_pid = fork();
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if (recycled_pid < 0)
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_exit(PIDFD_ERROR);
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if (recycled_pid == 0) {
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close(pipe_fds[1]);
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(void)read(pipe_fds[0], &c, 1);
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close(pipe_fds[0]);
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_exit(PIDFD_PASS);
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}
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/*
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* Stop the child so we can inspect whether we have
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* recycled pid PID_RECYCLE.
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*/
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close(pipe_fds[0]);
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ret = kill(recycled_pid, SIGSTOP);
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close(pipe_fds[1]);
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if (ret) {
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(void)wait_for_pid(recycled_pid);
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_exit(PIDFD_ERROR);
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}
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/*
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* We have recycled the pid. Try to signal it. This
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* needs to fail since this is a different process than
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* the one the pidfd refers to.
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*/
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if (recycled_pid == PID_RECYCLE) {
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ret = sys_pidfd_send_signal(pidfd, SIGCONT,
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NULL, 0);
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if (ret && errno == ESRCH)
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child_ret = PIDFD_XFAIL;
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else
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child_ret = PIDFD_FAIL;
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}
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/* let the process move on */
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ret = kill(recycled_pid, SIGCONT);
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if (ret)
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(void)kill(recycled_pid, SIGKILL);
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if (wait_for_pid(recycled_pid))
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_exit(PIDFD_ERROR);
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switch (child_ret) {
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case PIDFD_FAIL:
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/* fallthrough */
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case PIDFD_XFAIL:
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_exit(child_ret);
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case PIDFD_PASS:
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break;
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default:
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/* not reached */
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_exit(PIDFD_ERROR);
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}
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/*
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* If the user set a custom pid_max limit we could be
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* in the millions.
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* Skip the test in this case.
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*/
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if (recycled_pid > PIDFD_MAX_DEFAULT)
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_exit(PIDFD_SKIP);
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}
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/* failed to recycle pid */
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_exit(PIDFD_SKIP);
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}
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ret = wait_for_pid(pid1);
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switch (ret) {
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case PIDFD_FAIL:
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ksft_exit_fail_msg(
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"%s test: Managed to signal recycled pid %d\n",
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test_name, PID_RECYCLE);
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case PIDFD_PASS:
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ksft_exit_fail_msg("%s test: Failed to recycle pid %d\n",
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test_name, PID_RECYCLE);
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case PIDFD_SKIP:
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ksft_test_result_skip("%s test: Skipping test\n", test_name);
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ret = 0;
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break;
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case PIDFD_XFAIL:
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ksft_test_result_pass(
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"%s test: Failed to signal recycled pid as expected\n",
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test_name);
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ret = 0;
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break;
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default /* PIDFD_ERROR */:
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ksft_exit_fail_msg("%s test: Error while running tests\n",
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test_name);
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}
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return ret;
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}
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static int test_pidfd_send_signal_syscall_support(void)
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{
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int pidfd, ret;
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const char *test_name = "pidfd_send_signal check for support";
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pidfd = open("/proc/self", O_DIRECTORY | O_CLOEXEC);
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if (pidfd < 0)
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ksft_exit_fail_msg(
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"%s test: Failed to open process file descriptor\n",
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test_name);
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ret = sys_pidfd_send_signal(pidfd, 0, NULL, 0);
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if (ret < 0) {
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if (errno == ENOSYS) {
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ksft_test_result_skip(
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"%s test: pidfd_send_signal() syscall not supported\n",
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test_name);
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return 0;
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}
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ksft_exit_fail_msg("%s test: Failed to send signal\n",
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test_name);
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}
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have_pidfd_send_signal = true;
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close(pidfd);
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ksft_test_result_pass(
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"%s test: pidfd_send_signal() syscall is supported. Tests can be executed\n",
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test_name);
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return 0;
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}
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static void *test_pidfd_poll_exec_thread(void *priv)
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{
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ksft_print_msg("Child Thread: starting. pid %d tid %d ; and sleeping\n",
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getpid(), syscall(SYS_gettid));
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ksft_print_msg("Child Thread: doing exec of sleep\n");
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execl("/bin/sleep", "sleep", str(CHILD_THREAD_MIN_WAIT), (char *)NULL);
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ksft_print_msg("Child Thread: DONE. pid %d tid %d\n",
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getpid(), syscall(SYS_gettid));
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return NULL;
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}
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static void poll_pidfd(const char *test_name, int pidfd)
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{
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int c;
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int epoll_fd = epoll_create1(EPOLL_CLOEXEC);
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struct epoll_event event, events[MAX_EVENTS];
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if (epoll_fd == -1)
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ksft_exit_fail_msg("%s test: Failed to create epoll file descriptor "
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"(errno %d)\n",
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test_name, errno);
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event.events = EPOLLIN;
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event.data.fd = pidfd;
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if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, pidfd, &event)) {
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ksft_exit_fail_msg("%s test: Failed to add epoll file descriptor "
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"(errno %d)\n",
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test_name, errno);
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}
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c = epoll_wait(epoll_fd, events, MAX_EVENTS, 5000);
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if (c != 1 || !(events[0].events & EPOLLIN))
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ksft_exit_fail_msg("%s test: Unexpected epoll_wait result (c=%d, events=%x) "
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"(errno %d)\n",
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test_name, c, events[0].events, errno);
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close(epoll_fd);
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return;
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}
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static int child_poll_exec_test(void *args)
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{
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pthread_t t1;
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ksft_print_msg("Child (pidfd): starting. pid %d tid %d\n", getpid(),
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syscall(SYS_gettid));
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pthread_create(&t1, NULL, test_pidfd_poll_exec_thread, NULL);
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/*
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* Exec in the non-leader thread will destroy the leader immediately.
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* If the wait in the parent returns too soon, the test fails.
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*/
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while (1)
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sleep(1);
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return 0;
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}
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static void test_pidfd_poll_exec(int use_waitpid)
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{
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int pid, pidfd = 0;
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int status, ret;
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time_t prog_start = time(NULL);
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const char *test_name = "pidfd_poll check for premature notification on child thread exec";
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ksft_print_msg("Parent: pid: %d\n", getpid());
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pid = pidfd_clone(CLONE_PIDFD, &pidfd, child_poll_exec_test);
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if (pid < 0)
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ksft_exit_fail_msg("%s test: pidfd_clone failed (ret %d, errno %d)\n",
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test_name, pid, errno);
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ksft_print_msg("Parent: Waiting for Child (%d) to complete.\n", pid);
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if (use_waitpid) {
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ret = waitpid(pid, &status, 0);
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if (ret == -1)
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ksft_print_msg("Parent: error\n");
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if (ret == pid)
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ksft_print_msg("Parent: Child process waited for.\n");
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} else {
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poll_pidfd(test_name, pidfd);
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}
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time_t prog_time = time(NULL) - prog_start;
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ksft_print_msg("Time waited for child: %lu\n", prog_time);
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close(pidfd);
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if (prog_time < CHILD_THREAD_MIN_WAIT || prog_time > CHILD_THREAD_MIN_WAIT + 2)
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ksft_exit_fail_msg("%s test: Failed\n", test_name);
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else
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ksft_test_result_pass("%s test: Passed\n", test_name);
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}
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static void *test_pidfd_poll_leader_exit_thread(void *priv)
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{
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ksft_print_msg("Child Thread: starting. pid %d tid %d ; and sleeping\n",
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getpid(), syscall(SYS_gettid));
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sleep(CHILD_THREAD_MIN_WAIT);
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ksft_print_msg("Child Thread: DONE. pid %d tid %d\n", getpid(), syscall(SYS_gettid));
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return NULL;
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}
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static time_t *child_exit_secs;
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static int child_poll_leader_exit_test(void *args)
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{
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pthread_t t1, t2;
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ksft_print_msg("Child: starting. pid %d tid %d\n", getpid(), syscall(SYS_gettid));
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pthread_create(&t1, NULL, test_pidfd_poll_leader_exit_thread, NULL);
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pthread_create(&t2, NULL, test_pidfd_poll_leader_exit_thread, NULL);
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/*
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* glibc exit calls exit_group syscall, so explicity call exit only
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* so that only the group leader exits, leaving the threads alone.
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*/
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*child_exit_secs = time(NULL);
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syscall(SYS_exit, 0);
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/* Never reached, but appeases compiler thinking we should return. */
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exit(0);
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}
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static void test_pidfd_poll_leader_exit(int use_waitpid)
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{
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int pid, pidfd = 0;
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int status, ret = 0;
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const char *test_name = "pidfd_poll check for premature notification on non-empty"
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"group leader exit";
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child_exit_secs = mmap(NULL, sizeof *child_exit_secs, PROT_READ | PROT_WRITE,
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MAP_SHARED | MAP_ANONYMOUS, -1, 0);
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if (child_exit_secs == MAP_FAILED)
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ksft_exit_fail_msg("%s test: mmap failed (errno %d)\n",
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test_name, errno);
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ksft_print_msg("Parent: pid: %d\n", getpid());
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pid = pidfd_clone(CLONE_PIDFD, &pidfd, child_poll_leader_exit_test);
|
|
if (pid < 0)
|
|
ksft_exit_fail_msg("%s test: pidfd_clone failed (ret %d, errno %d)\n",
|
|
test_name, pid, errno);
|
|
|
|
ksft_print_msg("Parent: Waiting for Child (%d) to complete.\n", pid);
|
|
|
|
if (use_waitpid) {
|
|
ret = waitpid(pid, &status, 0);
|
|
if (ret == -1)
|
|
ksft_print_msg("Parent: error\n");
|
|
} else {
|
|
/*
|
|
* This sleep tests for the case where if the child exits, and is in
|
|
* EXIT_ZOMBIE, but the thread group leader is non-empty, then the poll
|
|
* doesn't prematurely return even though there are active threads
|
|
*/
|
|
sleep(1);
|
|
poll_pidfd(test_name, pidfd);
|
|
}
|
|
|
|
if (ret == pid)
|
|
ksft_print_msg("Parent: Child process waited for.\n");
|
|
|
|
time_t since_child_exit = time(NULL) - *child_exit_secs;
|
|
|
|
ksft_print_msg("Time since child exit: %lu\n", since_child_exit);
|
|
|
|
close(pidfd);
|
|
|
|
if (since_child_exit < CHILD_THREAD_MIN_WAIT ||
|
|
since_child_exit > CHILD_THREAD_MIN_WAIT + 2)
|
|
ksft_exit_fail_msg("%s test: Failed\n", test_name);
|
|
else
|
|
ksft_test_result_pass("%s test: Passed\n", test_name);
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
ksft_print_header();
|
|
ksft_set_plan(8);
|
|
|
|
test_pidfd_poll_exec(0);
|
|
test_pidfd_poll_exec(1);
|
|
test_pidfd_poll_leader_exit(0);
|
|
test_pidfd_poll_leader_exit(1);
|
|
test_pidfd_send_signal_syscall_support();
|
|
test_pidfd_send_signal_simple_success();
|
|
test_pidfd_send_signal_exited_fail();
|
|
test_pidfd_send_signal_recycled_pid_fail();
|
|
|
|
return ksft_exit_pass();
|
|
}
|