Linux: Add epoll_pwait2 (BZ #27359)

It is similar to epoll_wait, with the difference the timeout has
nanosecond resoluting by using struct timespec instead of int.

Although Linux interface only provides 64 bit time_t support, old
32 bit interface is also provided (so keep in sync with current
practice and to no force opt-in on 64 bit time_t).

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

1 files changed, 211 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/tst-epoll.c b/sysdeps/unix/sysv/linux/tst-epoll.c
new file mode 100644
index 0000000000..3ef6ca9fbd
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-epoll.c
@@ -0,0 +1,211 @@
+/* Basic tests for Linux epoll_* wrappers.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <intprops.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xsignal.h>
+#include <support/xunistd.h>
+#include <support/xtime.h>
+#include <stdlib.h>
+#include <sys/epoll.h>
+
+/* The test focus on checking if the timeout argument is correctly handled
+   by glibc wrappers.  */
+
+static void
+handler (int sig)
+{
+}
+
+typedef int (*epoll_wait_check_t) (int, struct epoll_event *, int,
+				   int, const sigset_t *);
+
+static void
+test_epoll_basic (epoll_wait_check_t epoll_wait_check)
+{
+  {
+    sigset_t ss_usr1;
+    sigemptyset (&ss_usr1);
+    sigaddset (&ss_usr1, SIGUSR1);
+    TEST_COMPARE (sigprocmask (SIG_BLOCK, &ss_usr1, NULL), 0);
+  }
+
+  int fds[2][2];
+  xpipe (fds[0]);
+  xpipe (fds[1]);
+
+  sigset_t ss;
+  TEST_COMPARE (sigprocmask (SIG_SETMASK, NULL, &ss), 0);
+  sigdelset (&ss, SIGUSR1);
+
+  int efd = epoll_create1 (0);
+  TEST_VERIFY_EXIT (efd != -1);
+
+  struct epoll_event event;
+
+  event.data.fd = fds[1][0];
+  event.events = EPOLLIN | EPOLLET;
+  TEST_COMPARE (epoll_ctl (efd, EPOLL_CTL_ADD, fds[1][0], &event), 0);
+
+  pid_t parent = getpid ();
+  pid_t p = xfork ();
+  if (p == 0)
+    {
+      xclose (fds[0][1]);
+      xclose (fds[1][0]);
+
+      event.data.fd = fds[0][0];
+      event.events = EPOLLIN | EPOLLET;
+      TEST_COMPARE (epoll_ctl (efd, EPOLL_CTL_ADD, fds[0][0], &event), 0);
+
+      int e;
+      do
+	{
+	  if (getppid () != parent)
+	    FAIL_EXIT1 ("getppid()=%d != parent=%d", getppid(), parent);
+
+	  errno = 0;
+	  e = epoll_wait_check (efd, &event, 1, 500, &ss);
+	}
+      while (e == 0);
+
+      TEST_COMPARE (e, -1);
+      TEST_COMPARE (errno, EINTR);
+
+      TEMP_FAILURE_RETRY (write (fds[1][1], "foo", 3));
+
+      exit (0);
+    }
+
+  xclose (fds[0][0]);
+  xclose (fds[1][1]);
+
+  /* Wait some time so child is blocked on the syscall.  */
+  nanosleep (&(struct timespec) {0, 10000000}, NULL);
+  TEST_COMPARE (kill (p, SIGUSR1), 0);
+
+  int e = epoll_wait_check (efd, &event, 1, 500000000, &ss);
+  TEST_COMPARE (e, 1);
+  TEST_VERIFY (event.events & EPOLLIN);
+
+  xclose (fds[0][1]);
+  xclose (fds[1][0]);
+  xclose (efd);
+}
+
+
+static void
+test_epoll_large_timeout (epoll_wait_check_t epoll_wait_check)
+{
+  timer_t t = support_create_timer (0, 100000000, true, NULL);
+
+  int fds[2];
+  xpipe (fds);
+
+  fd_set rfds;
+  FD_ZERO (&rfds);
+  FD_SET (fds[0], &rfds);
+
+  sigset_t ss;
+  TEST_COMPARE (sigprocmask (SIG_SETMASK, NULL, &ss), 0);
+  sigdelset (&ss, SIGALRM);
+
+  int efd = epoll_create1 (0);
+  TEST_VERIFY_EXIT (efd != -1);
+
+  struct epoll_event event;
+  event.data.fd = fds[0];
+  event.events = EPOLLIN | EPOLLET;
+  TEST_COMPARE (epoll_ctl (efd, EPOLL_CTL_ADD, fds[0], &event), 0);
+
+  int tmo = TYPE_MAXIMUM (int);
+  TEST_COMPARE (epoll_wait_check (efd, &event, 1, tmo, &ss), -1);
+  TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);
+
+  TEST_COMPARE (epoll_wait_check (efd, &event, 1, -1, &ss), -1);
+  TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);
+
+  support_delete_timer (t);
+
+  xclose (fds[0]);
+  xclose (fds[1]);
+  xclose (efd);
+}
+
+
+static int
+epoll_wait_check (int epfd, struct epoll_event *ev, int maxev, int tmo,
+		  const sigset_t *ss)
+{
+  sigset_t orig;
+  TEST_COMPARE (sigprocmask (SIG_SETMASK, ss, &orig), 0);
+  int r = epoll_wait (epfd, ev, maxev, tmo);
+  TEST_COMPARE (sigprocmask (SIG_SETMASK, &orig, NULL), 0);
+  return r;
+}
+
+static int
+epoll_pwait_check (int epfd, struct epoll_event *ev, int maxev, int tmo,
+		   const sigset_t *ss)
+{
+  return epoll_pwait (epfd, ev, maxev, tmo, ss);
+}
+
+static int
+epoll_pwait2_check (int epfd, struct epoll_event *ev, int maxev, int tmo,
+		    const sigset_t *ss)
+{
+  time_t s = tmo == -1 ? TYPE_MAXIMUM (time_t) : tmo / 1000;
+  long int ns = tmo == -1 ? 0 : (tmo % 1000) * 1000000;
+  return epoll_pwait2 (epfd, ev, maxev, &(struct timespec) { s, ns }, ss);
+}
+
+static int
+do_test (void)
+{
+  {
+    struct sigaction sa;
+    sa.sa_handler = handler;
+    sa.sa_flags = 0;
+    sigemptyset (&sa.sa_mask);
+    xsigaction (SIGUSR1, &sa, NULL);
+
+    sa.sa_handler = SIG_IGN;
+    xsigaction (SIGCHLD, &sa, NULL);
+  }
+
+  int r = epoll_pwait2 (-1, NULL, 0, NULL, NULL);
+  TEST_COMPARE (r, -1);
+  bool pwait2_supported = errno != ENOSYS;
+
+  test_epoll_basic (epoll_wait_check);
+  test_epoll_basic (epoll_pwait_check);
+  if (pwait2_supported)
+    test_epoll_basic (epoll_pwait2_check);
+
+  test_epoll_large_timeout (epoll_wait_check);
+  test_epoll_large_timeout (epoll_pwait_check);
+  if (pwait2_supported)
+    test_epoll_large_timeout (epoll_pwait2_check);
+
+  return 0;
+}
+
+#include <support/test-driver.c>