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-rw-r--r--tools/testing/selftests/pidfd/pidfd_test.c575
1 files changed, 575 insertions, 0 deletions
diff --git a/tools/testing/selftests/pidfd/pidfd_test.c b/tools/testing/selftests/pidfd/pidfd_test.c
new file mode 100644
index 000000000..cf4f3174c
--- /dev/null
+++ b/tools/testing/selftests/pidfd/pidfd_test.c
@@ -0,0 +1,575 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/types.h>
+#include <pthread.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <sys/epoll.h>
+#include <sys/mman.h>
+#include <sys/mount.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "pidfd.h"
+#include "../kselftest.h"
+
+#define str(s) _str(s)
+#define _str(s) #s
+#define CHILD_THREAD_MIN_WAIT 3 /* seconds */
+
+#define MAX_EVENTS 5
+
+static bool have_pidfd_send_signal;
+
+static pid_t pidfd_clone(int flags, int *pidfd, int (*fn)(void *))
+{
+ size_t stack_size = 1024;
+ char *stack[1024] = { 0 };
+
+#ifdef __ia64__
+ return __clone2(fn, stack, stack_size, flags | SIGCHLD, NULL, pidfd);
+#else
+ return clone(fn, stack + stack_size, flags | SIGCHLD, NULL, pidfd);
+#endif
+}
+
+static int signal_received;
+
+static void set_signal_received_on_sigusr1(int sig)
+{
+ if (sig == SIGUSR1)
+ signal_received = 1;
+}
+
+/*
+ * Straightforward test to see whether pidfd_send_signal() works is to send
+ * a signal to ourself.
+ */
+static int test_pidfd_send_signal_simple_success(void)
+{
+ int pidfd, ret;
+ const char *test_name = "pidfd_send_signal send SIGUSR1";
+
+ if (!have_pidfd_send_signal) {
+ ksft_test_result_skip(
+ "%s test: pidfd_send_signal() syscall not supported\n",
+ test_name);
+ return 0;
+ }
+
+ pidfd = open("/proc/self", O_DIRECTORY | O_CLOEXEC);
+ if (pidfd < 0)
+ ksft_exit_fail_msg(
+ "%s test: Failed to open process file descriptor\n",
+ test_name);
+
+ signal(SIGUSR1, set_signal_received_on_sigusr1);
+
+ ret = sys_pidfd_send_signal(pidfd, SIGUSR1, NULL, 0);
+ close(pidfd);
+ if (ret < 0)
+ ksft_exit_fail_msg("%s test: Failed to send signal\n",
+ test_name);
+
+ if (signal_received != 1)
+ ksft_exit_fail_msg("%s test: Failed to receive signal\n",
+ test_name);
+
+ signal_received = 0;
+ ksft_test_result_pass("%s test: Sent signal\n", test_name);
+ return 0;
+}
+
+static int test_pidfd_send_signal_exited_fail(void)
+{
+ int pidfd, ret, saved_errno;
+ char buf[256];
+ pid_t pid;
+ const char *test_name = "pidfd_send_signal signal exited process";
+
+ if (!have_pidfd_send_signal) {
+ ksft_test_result_skip(
+ "%s test: pidfd_send_signal() syscall not supported\n",
+ test_name);
+ return 0;
+ }
+
+ pid = fork();
+ if (pid < 0)
+ ksft_exit_fail_msg("%s test: Failed to create new process\n",
+ test_name);
+
+ if (pid == 0)
+ _exit(EXIT_SUCCESS);
+
+ snprintf(buf, sizeof(buf), "/proc/%d", pid);
+
+ pidfd = open(buf, O_DIRECTORY | O_CLOEXEC);
+
+ (void)wait_for_pid(pid);
+
+ if (pidfd < 0)
+ ksft_exit_fail_msg(
+ "%s test: Failed to open process file descriptor\n",
+ test_name);
+
+ ret = sys_pidfd_send_signal(pidfd, 0, NULL, 0);
+ saved_errno = errno;
+ close(pidfd);
+ if (ret == 0)
+ ksft_exit_fail_msg(
+ "%s test: Managed to send signal to process even though it should have failed\n",
+ test_name);
+
+ if (saved_errno != ESRCH)
+ ksft_exit_fail_msg(
+ "%s test: Expected to receive ESRCH as errno value but received %d instead\n",
+ test_name, saved_errno);
+
+ ksft_test_result_pass("%s test: Failed to send signal as expected\n",
+ test_name);
+ return 0;
+}
+
+/*
+ * 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
+ * times then we skip the test to not go into an infinite loop or block for a
+ * long time.
+ */
+#define PIDFD_MAX_DEFAULT 0x8000
+
+static int test_pidfd_send_signal_recycled_pid_fail(void)
+{
+ int i, ret;
+ pid_t pid1;
+ const char *test_name = "pidfd_send_signal signal recycled pid";
+
+ if (!have_pidfd_send_signal) {
+ ksft_test_result_skip(
+ "%s test: pidfd_send_signal() syscall not supported\n",
+ test_name);
+ return 0;
+ }
+
+ ret = unshare(CLONE_NEWPID);
+ if (ret < 0) {
+ if (errno == EPERM) {
+ ksft_test_result_skip("%s test: Unsharing pid namespace not permitted\n",
+ test_name);
+ return 0;
+ }
+ ksft_exit_fail_msg("%s test: Failed to unshare pid namespace\n",
+ test_name);
+ }
+
+ ret = unshare(CLONE_NEWNS);
+ if (ret < 0) {
+ if (errno == EPERM) {
+ ksft_test_result_skip("%s test: Unsharing mount namespace not permitted\n",
+ test_name);
+ return 0;
+ }
+ ksft_exit_fail_msg("%s test: Failed to unshare mount namespace\n",
+ test_name);
+ }
+
+ ret = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0);
+ if (ret < 0)
+ ksft_exit_fail_msg("%s test: Failed to remount / private\n",
+ test_name);
+
+ /* pid 1 in new pid namespace */
+ pid1 = fork();
+ if (pid1 < 0)
+ ksft_exit_fail_msg("%s test: Failed to create new process\n",
+ test_name);
+
+ if (pid1 == 0) {
+ char buf[256];
+ pid_t pid2;
+ int pidfd = -1;
+
+ (void)umount2("/proc", MNT_DETACH);
+ ret = mount("proc", "/proc", "proc", 0, NULL);
+ if (ret < 0)
+ _exit(PIDFD_ERROR);
+
+ /* grab pid PID_RECYCLE */
+ for (i = 0; i <= PIDFD_MAX_DEFAULT; i++) {
+ pid2 = fork();
+ if (pid2 < 0)
+ _exit(PIDFD_ERROR);
+
+ if (pid2 == 0)
+ _exit(PIDFD_PASS);
+
+ if (pid2 == PID_RECYCLE) {
+ snprintf(buf, sizeof(buf), "/proc/%d", pid2);
+ ksft_print_msg("pid to recycle is %d\n", pid2);
+ pidfd = open(buf, O_DIRECTORY | O_CLOEXEC);
+ }
+
+ if (wait_for_pid(pid2))
+ _exit(PIDFD_ERROR);
+
+ if (pid2 >= PID_RECYCLE)
+ break;
+ }
+
+ /*
+ * We want to be as predictable as we can so if we haven't been
+ * able to grab pid PID_RECYCLE skip the test.
+ */
+ if (pid2 != PID_RECYCLE) {
+ /* skip test */
+ close(pidfd);
+ _exit(PIDFD_SKIP);
+ }
+
+ if (pidfd < 0)
+ _exit(PIDFD_ERROR);
+
+ for (i = 0; i <= PIDFD_MAX_DEFAULT; i++) {
+ char c;
+ int pipe_fds[2];
+ pid_t recycled_pid;
+ int child_ret = PIDFD_PASS;
+
+ ret = pipe2(pipe_fds, O_CLOEXEC);
+ if (ret < 0)
+ _exit(PIDFD_ERROR);
+
+ recycled_pid = fork();
+ if (recycled_pid < 0)
+ _exit(PIDFD_ERROR);
+
+ if (recycled_pid == 0) {
+ close(pipe_fds[1]);
+ (void)read(pipe_fds[0], &c, 1);
+ close(pipe_fds[0]);
+
+ _exit(PIDFD_PASS);
+ }
+
+ /*
+ * Stop the child so we can inspect whether we have
+ * recycled pid PID_RECYCLE.
+ */
+ close(pipe_fds[0]);
+ ret = kill(recycled_pid, SIGSTOP);
+ close(pipe_fds[1]);
+ if (ret) {
+ (void)wait_for_pid(recycled_pid);
+ _exit(PIDFD_ERROR);
+ }
+
+ /*
+ * We have recycled the pid. Try to signal it. This
+ * needs to fail since this is a different process than
+ * the one the pidfd refers to.
+ */
+ if (recycled_pid == PID_RECYCLE) {
+ ret = sys_pidfd_send_signal(pidfd, SIGCONT,
+ NULL, 0);
+ if (ret && errno == ESRCH)
+ child_ret = PIDFD_XFAIL;
+ else
+ child_ret = PIDFD_FAIL;
+ }
+
+ /* let the process move on */
+ ret = kill(recycled_pid, SIGCONT);
+ if (ret)
+ (void)kill(recycled_pid, SIGKILL);
+
+ if (wait_for_pid(recycled_pid))
+ _exit(PIDFD_ERROR);
+
+ switch (child_ret) {
+ case PIDFD_FAIL:
+ /* fallthrough */
+ case PIDFD_XFAIL:
+ _exit(child_ret);
+ case PIDFD_PASS:
+ break;
+ default:
+ /* not reached */
+ _exit(PIDFD_ERROR);
+ }
+
+ /*
+ * If the user set a custom pid_max limit we could be
+ * in the millions.
+ * Skip the test in this case.
+ */
+ if (recycled_pid > PIDFD_MAX_DEFAULT)
+ _exit(PIDFD_SKIP);
+ }
+
+ /* failed to recycle pid */
+ _exit(PIDFD_SKIP);
+ }
+
+ ret = wait_for_pid(pid1);
+ switch (ret) {
+ case PIDFD_FAIL:
+ ksft_exit_fail_msg(
+ "%s test: Managed to signal recycled pid %d\n",
+ test_name, PID_RECYCLE);
+ case PIDFD_PASS:
+ ksft_exit_fail_msg("%s test: Failed to recycle pid %d\n",
+ test_name, PID_RECYCLE);
+ case PIDFD_SKIP:
+ ksft_test_result_skip("%s test: Skipping test\n", test_name);
+ ret = 0;
+ break;
+ case PIDFD_XFAIL:
+ ksft_test_result_pass(
+ "%s test: Failed to signal recycled pid as expected\n",
+ test_name);
+ ret = 0;
+ break;
+ default /* PIDFD_ERROR */:
+ ksft_exit_fail_msg("%s test: Error while running tests\n",
+ test_name);
+ }
+
+ return ret;
+}
+
+static int test_pidfd_send_signal_syscall_support(void)
+{
+ int pidfd, ret;
+ const char *test_name = "pidfd_send_signal check for support";
+
+ pidfd = open("/proc/self", O_DIRECTORY | O_CLOEXEC);
+ if (pidfd < 0)
+ ksft_exit_fail_msg(
+ "%s test: Failed to open process file descriptor\n",
+ test_name);
+
+ ret = sys_pidfd_send_signal(pidfd, 0, NULL, 0);
+ if (ret < 0) {
+ if (errno == ENOSYS) {
+ ksft_test_result_skip(
+ "%s test: pidfd_send_signal() syscall not supported\n",
+ test_name);
+ return 0;
+ }
+ ksft_exit_fail_msg("%s test: Failed to send signal\n",
+ test_name);
+ }
+
+ have_pidfd_send_signal = true;
+ close(pidfd);
+ ksft_test_result_pass(
+ "%s test: pidfd_send_signal() syscall is supported. Tests can be executed\n",
+ test_name);
+ return 0;
+}
+
+static void *test_pidfd_poll_exec_thread(void *priv)
+{
+ ksft_print_msg("Child Thread: starting. pid %d tid %ld ; and sleeping\n",
+ getpid(), syscall(SYS_gettid));
+ ksft_print_msg("Child Thread: doing exec of sleep\n");
+
+ execl("/bin/sleep", "sleep", str(CHILD_THREAD_MIN_WAIT), (char *)NULL);
+
+ ksft_print_msg("Child Thread: DONE. pid %d tid %ld\n",
+ getpid(), syscall(SYS_gettid));
+ return NULL;
+}
+
+static void poll_pidfd(const char *test_name, int pidfd)
+{
+ int c;
+ int epoll_fd = epoll_create1(EPOLL_CLOEXEC);
+ struct epoll_event event, events[MAX_EVENTS];
+
+ if (epoll_fd == -1)
+ ksft_exit_fail_msg("%s test: Failed to create epoll file descriptor "
+ "(errno %d)\n",
+ test_name, errno);
+
+ event.events = EPOLLIN;
+ event.data.fd = pidfd;
+
+ if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, pidfd, &event)) {
+ ksft_exit_fail_msg("%s test: Failed to add epoll file descriptor "
+ "(errno %d)\n",
+ test_name, errno);
+ }
+
+ c = epoll_wait(epoll_fd, events, MAX_EVENTS, 5000);
+ if (c != 1 || !(events[0].events & EPOLLIN))
+ ksft_exit_fail_msg("%s test: Unexpected epoll_wait result (c=%d, events=%x) "
+ "(errno %d)\n",
+ test_name, c, events[0].events, errno);
+
+ close(epoll_fd);
+ return;
+
+}
+
+static int child_poll_exec_test(void *args)
+{
+ pthread_t t1;
+
+ ksft_print_msg("Child (pidfd): starting. pid %d tid %ld\n", getpid(),
+ syscall(SYS_gettid));
+ pthread_create(&t1, NULL, test_pidfd_poll_exec_thread, NULL);
+ /*
+ * Exec in the non-leader thread will destroy the leader immediately.
+ * If the wait in the parent returns too soon, the test fails.
+ */
+ while (1)
+ sleep(1);
+
+ return 0;
+}
+
+static void test_pidfd_poll_exec(int use_waitpid)
+{
+ int pid, pidfd = 0;
+ int status, ret;
+ time_t prog_start = time(NULL);
+ const char *test_name = "pidfd_poll check for premature notification on child thread exec";
+
+ ksft_print_msg("Parent: pid: %d\n", getpid());
+ pid = pidfd_clone(CLONE_PIDFD, &pidfd, child_poll_exec_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");
+
+ if (ret == pid)
+ ksft_print_msg("Parent: Child process waited for.\n");
+ } else {
+ poll_pidfd(test_name, pidfd);
+ }
+
+ time_t prog_time = time(NULL) - prog_start;
+
+ ksft_print_msg("Time waited for child: %lu\n", prog_time);
+
+ close(pidfd);
+
+ if (prog_time < CHILD_THREAD_MIN_WAIT || prog_time > 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);
+}
+
+static void *test_pidfd_poll_leader_exit_thread(void *priv)
+{
+ ksft_print_msg("Child Thread: starting. pid %d tid %ld ; and sleeping\n",
+ getpid(), syscall(SYS_gettid));
+ sleep(CHILD_THREAD_MIN_WAIT);
+ ksft_print_msg("Child Thread: DONE. pid %d tid %ld\n", getpid(), syscall(SYS_gettid));
+ return NULL;
+}
+
+static time_t *child_exit_secs;
+static int child_poll_leader_exit_test(void *args)
+{
+ pthread_t t1, t2;
+
+ ksft_print_msg("Child: starting. pid %d tid %ld\n", getpid(), syscall(SYS_gettid));
+ pthread_create(&t1, NULL, test_pidfd_poll_leader_exit_thread, NULL);
+ pthread_create(&t2, NULL, test_pidfd_poll_leader_exit_thread, NULL);
+
+ /*
+ * glibc exit calls exit_group syscall, so explicity call exit only
+ * so that only the group leader exits, leaving the threads alone.
+ */
+ *child_exit_secs = time(NULL);
+ syscall(SYS_exit, 0);
+ /* Never reached, but appeases compiler thinking we should return. */
+ exit(0);
+}
+
+static void test_pidfd_poll_leader_exit(int use_waitpid)
+{
+ int pid, pidfd = 0;
+ int status, ret = 0;
+ const char *test_name = "pidfd_poll check for premature notification on non-empty"
+ "group leader exit";
+
+ child_exit_secs = mmap(NULL, sizeof *child_exit_secs, PROT_READ | PROT_WRITE,
+ MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+
+ if (child_exit_secs == MAP_FAILED)
+ ksft_exit_fail_msg("%s test: mmap failed (errno %d)\n",
+ test_name, errno);
+
+ ksft_print_msg("Parent: pid: %d\n", getpid());
+ 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();
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-13 09:16:41 +0000