183 lines
5.2 KiB
C
183 lines
5.2 KiB
C
/* Basic tests for Linux pidfd interfaces.
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Copyright (C) 2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <fcntl.h>
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#include <support/capture_subprocess.h>
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#include <support/check.h>
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#include <support/process_state.h>
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#include <support/support.h>
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#include <support/xsignal.h>
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#include <support/xunistd.h>
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#include <support/xsocket.h>
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#include <sys/pidfd.h>
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#include <sys/wait.h>
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#define REMOTE_PATH "/dev/null"
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/* The pair of sockets used for coordination. The subprocess uses
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sockets[1]. */
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static int sockets[2];
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static pid_t ppid;
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static uid_t puid;
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static void
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sighandler (int sig)
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{
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}
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static void
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subprocess (void)
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{
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xsignal (SIGUSR1, sighandler);
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xsignal (SIGUSR2, sighandler);
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/* Check first pidfd_send_signal with default NULL siginfo_t argument. */
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{
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sigset_t set;
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sigemptyset (&set);
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sigaddset (&set, SIGUSR1);
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siginfo_t info;
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TEST_COMPARE (sigtimedwait (&set, &info, NULL), SIGUSR1);
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TEST_COMPARE (info.si_signo, SIGUSR1);
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TEST_COMPARE (info.si_errno, 0);
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TEST_COMPARE (info.si_code, SI_USER);
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TEST_COMPARE (info.si_pid, ppid);
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TEST_COMPARE (info.si_uid, puid);
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}
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/* Check second pidfd_send_signal with crafted siginfo_t argument. */
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{
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sigset_t set;
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sigemptyset (&set);
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sigaddset (&set, SIGUSR2);
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siginfo_t info;
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TEST_COMPARE (sigtimedwait (&set, &info, NULL), SIGUSR2);
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TEST_COMPARE (info.si_signo, SIGUSR2);
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TEST_COMPARE (info.si_errno, EAGAIN);
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TEST_COMPARE (info.si_code, -10);
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TEST_COMPARE (info.si_pid, ppid);
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TEST_COMPARE (info.si_uid, puid);
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}
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/* Send a local file descriptor value to check pidfd_getfd. */
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int remote_fd = xopen (REMOTE_PATH, O_WRONLY | O_CLOEXEC, 0);
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xsendto (sockets[1], &remote_fd, sizeof (remote_fd), 0, NULL, 0);
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/* Wait for final pidfd_send_signal. */
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pause ();
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_exit (0);
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}
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static int
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do_test (void)
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{
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{
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/* The pidfd_getfd syscall was the last in the set of pidfd related
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syscalls added to the kernel. Use pidfd_getfd to decide if this
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kernel has pidfd support that we can test. */
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int r = pidfd_getfd (0, 0, 1);
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TEST_VERIFY_EXIT (r == -1);
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if (errno == ENOSYS)
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FAIL_UNSUPPORTED ("kernel does not support pidfd_getfd, skipping test");
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}
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ppid = getpid ();
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puid = getuid ();
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TEST_COMPARE (socketpair (AF_UNIX, SOCK_STREAM, 0, sockets), 0);
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pid_t pid = xfork ();
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if (pid == 0)
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{
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xclose (sockets[0]);
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subprocess ();
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}
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xclose (sockets[1]);
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TEST_COMPARE (pidfd_open (-1, 0), -1);
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TEST_COMPARE (errno, EINVAL);
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int pidfd = pidfd_open (pid, 0);
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TEST_VERIFY (pidfd != -1);
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/* Wait for first sigtimedwait. */
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support_process_state_wait (pid, support_process_state_sleeping);
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TEST_COMPARE (pidfd_send_signal (pidfd, SIGUSR1, NULL, 0), 0);
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/* Wait for second sigtimedwait. */
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support_process_state_wait (pid, support_process_state_sleeping);
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{
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siginfo_t info =
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{
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.si_signo = SIGUSR2,
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.si_errno = EAGAIN,
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.si_code = -10,
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.si_pid = ppid,
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.si_uid = puid
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};
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TEST_COMPARE (pidfd_send_signal (pidfd, SIGUSR2, &info, 0), 0);
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}
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/* Get remote file descriptor to check for pidfd_getfd. */
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{
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int remote_fd;
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xrecvfrom (sockets[0], &remote_fd, sizeof (remote_fd), 0, NULL, 0);
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int fd = pidfd_getfd (pidfd, remote_fd, 0);
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/* pidfd_getfd may fail with EPERM if the process does not have
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PTRACE_MODE_ATTACH_REALCREDS permissions. This means the call
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may be denied if the process doesn't have CAP_SYS_PTRACE or
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if a LSM security_ptrace_access_check denies access. */
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if (fd == -1 && errno == EPERM)
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{
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TEST_COMPARE (pidfd_send_signal (pidfd, SIGKILL, NULL, 0), 0);
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FAIL_UNSUPPORTED ("don't have permission to use pidfd_getfd on pidfd, "
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"skipping test");
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}
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TEST_VERIFY (fd > 0);
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char *path = xasprintf ("/proc/%d/fd/%d", pid, remote_fd);
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char *resolved = xreadlink (path);
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TEST_COMPARE_STRING (resolved, REMOTE_PATH);
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int remote_fd_mode = fcntl (fd, F_GETFL);
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TEST_VERIFY (remote_fd_mode != -1);
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TEST_VERIFY (remote_fd_mode & O_WRONLY);
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int remote_fd_flags = fcntl (fd, F_GETFD);
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TEST_VERIFY (remote_fd_flags != -1);
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TEST_VERIFY (remote_fd_flags & FD_CLOEXEC);
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}
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TEST_COMPARE (pidfd_send_signal (pidfd, SIGKILL, NULL, 0), 0);
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{
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siginfo_t info;
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int r = waitid (P_PIDFD, pidfd, &info, WEXITED);
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TEST_COMPARE (r, 0);
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TEST_COMPARE (info.si_status, SIGKILL);
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TEST_COMPARE (info.si_code, CLD_KILLED);
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}
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return 0;
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}
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#include <support/test-driver.c>
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