debug: test for more required cacellation points (BZ# 29274)

Generalize the test for cancellation point in __read_chk to also test
the other fortified functions with required cancellation points.

Since there is not easy way to force some syscalls to block (for
instance pread) the test tests two modes: cancellation on blocked
syscalls and early cancellation on pending request.

Checked on x86_64-linux-gnu and aarch64-linux-gnu.

Co-authored-by: Andreas Schwab <schwab@suse.de>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

debug/Makefile

@@ -110,7 +110,7 @@ CPPFLAGS-tst-longjmp_chk2.c += -D_FORTIFY_SOURCE=1
 CFLAGS-tst-longjmp_chk3.c += -fexceptions -fasynchronous-unwind-tables
 CPPFLAGS-tst-longjmp_chk3.c += -D_FORTIFY_SOURCE=1
 CPPFLAGS-tst-realpath-chk.c += -D_FORTIFY_SOURCE=2
-CPPFLAGS-tst-read-chk-cancel.c += -D_FORTIFY_SOURCE=2
+CPPFLAGS-tst-chk-cancel.c += -D_FORTIFY_SOURCE=2
 
 # _FORTIFY_SOURCE tests.
 # Auto-generate tests for _FORTIFY_SOURCE for different levels, compilers and
@@ -206,7 +206,7 @@ tests += tst-ssp-1
 endif
 
 ifeq ($(have-thread-library), yes)
-tests += tst-read-chk-cancel
+tests += tst-chk-cancel
 endif
 
 ifeq (,$(CXX))
@@ -248,4 +248,4 @@ $(objpfx)xtrace: xtrace.sh
 	    -e 's|@REPORT_BUGS_TO@|$(REPORT_BUGS_TO)|' $^ > $@.new \
 	&& rm -f $@ && mv $@.new $@ && chmod +x $@
 
-$(objpfx)tst-read-chk-cancel: $(shared-thread-library)
+$(objpfx)tst-chk-cancel: $(shared-thread-library)

debug/tst-chk-cancel.c

@@ -0,0 +1,263 @@
+/* Test for required cancellation points in fortified functions (BZ #29274)
+   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 <array_length.h>
+#include <errno.h>
+#include <poll.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <support/check.h>
+#include <support/xthread.h>
+#include <support/xunistd.h>
+#include <sys/socket.h>
+
+/* Cleanup handling test.  */
+static int cl_called;
+
+static void
+cl (void *arg)
+{
+  ++cl_called;
+}
+
+static int fds[2];
+static pthread_barrier_t barrier;
+
+static void *
+tf_read (void *n)
+{
+  pthread_cleanup_push (cl, NULL);
+
+  xpthread_barrier_wait (&barrier);
+
+  /* This call should be forwarded to __read_chk because the buffer size
+     is known, but the read length is non-constant.  */
+  char c;
+  if (read (fds[0], &c, (uintptr_t) n) != 1)
+    return (void *) -1L;
+
+  pthread_cleanup_pop (0);
+  return 0;
+}
+
+static void *
+tf_pread (void *n)
+{
+  pthread_cleanup_push (cl, NULL);
+
+  xpthread_barrier_wait (&barrier);
+
+  /* This call should be forwarded to __pread_chk because the buffer size
+     is known, but the read length is non-constant.  */
+  char c;
+  if (pread (fds[0], &c, (uintptr_t) n, 0) != 1)
+    return (void *) -1L;
+
+  pthread_cleanup_pop (0);
+  return 0;
+}
+
+static void *
+tf_pread64 (void *n)
+{
+  pthread_cleanup_push (cl, NULL);
+
+  xpthread_barrier_wait (&barrier);
+
+  /* This call should be forwarded to __pread64_chk because the buffer size
+     is known, but the read length is non-constant.  */
+  char c;
+  if (pread64 (fds[0], &c, (uintptr_t) n, 0) != 1)
+    return (void *) -1L;
+
+  pthread_cleanup_pop (0);
+  return 0;
+}
+
+static void *
+tf_poll (void *n)
+{
+  pthread_cleanup_push (cl, NULL);
+
+  xpthread_barrier_wait (&barrier);
+
+  /* This call should be forwarded to __poll_chk because the pollfd size
+     is known, but the number of entries is non-constant.  */
+  struct pollfd pfd = { fds[0], POLLIN, 0 };
+  if (poll (&pfd, (uintptr_t) n, -1) != 1)
+    return (void *) -1L;
+
+  pthread_cleanup_pop (0);
+  return 0;
+}
+
+static void *
+tf_ppoll (void *n)
+{
+  pthread_cleanup_push (cl, NULL);
+
+  xpthread_barrier_wait (&barrier);
+
+  /* This call should be forwarded to __ppoll_chk because the pollfd size
+     is known, but the number of entries is non-constant.  */
+  struct pollfd pfd = { fds[0], POLLIN, 0 };
+  if (ppoll (&pfd, (uintptr_t) n, 0, 0) != 1)
+    return (void *) -1L;
+
+  pthread_cleanup_pop (0);
+  return 0;
+}
+
+static void *
+tf_recv (void *n)
+{
+  pthread_cleanup_push (cl, NULL);
+
+  xpthread_barrier_wait (&barrier);
+
+  /* This call should be forwarded to __ppoll_chk because the pollfd size
+     is known, but the number of entries is non-constant.  */
+  char c;
+  if (recv (fds[0], &c, (uintptr_t) n, 0) != 1)
+    return (void *) -1L;
+
+  pthread_cleanup_pop (0);
+  return 0;
+}
+
+static void *
+tf_recvfrom (void *n)
+{
+  pthread_cleanup_push (cl, NULL);
+
+  xpthread_barrier_wait (&barrier);
+
+  /* This call should be forwarded to __ppoll_chk because the pollfd size
+     is known, but the number of entries is non-constant.  */
+  char c;
+  if (recvfrom (fds[0], &c, (uintptr_t) n, 0, NULL, NULL) != 1)
+    return (void *) -1L;
+
+  pthread_cleanup_pop (0);
+  return 0;
+}
+
+static struct cancel_tests
+{
+  const char *name;
+  void *(*tf) (void *);
+  bool only_early;
+#define ADD_TEST(name, early) { #name, tf_##name, early }
+} tests[] =
+{
+  ADD_TEST (poll,     false),
+  ADD_TEST (ppoll,    false),
+  ADD_TEST (pread,    true),
+  ADD_TEST (pread64,  true),
+  ADD_TEST (read,     false),
+  ADD_TEST (recv,     false),
+  ADD_TEST (recvfrom, false),
+};
+
+/* Set the send buffer of socket S to 1 byte so any send operation
+   done with WRITE_BUFFER_SIZE bytes will force syscall blocking.  */
+static void
+set_socket_buffer (int s)
+{
+  int val = 1;
+  socklen_t len = sizeof (val);
+
+  TEST_VERIFY_EXIT (setsockopt (s, SOL_SOCKET, SO_SNDBUF, &val,
+                    sizeof (val)) == 0);
+  TEST_VERIFY_EXIT (getsockopt (s, SOL_SOCKET, SO_SNDBUF, &val, &len) == 0);
+  printf ("%s: got size %d\n", __func__, val);
+}
+
+static int
+do_test (void)
+{
+  xpthread_barrier_init (&barrier, 0, 2);
+
+  if (socketpair (AF_UNIX, SOCK_STREAM, 0, fds) != 0)
+    FAIL_EXIT1 ("socketpair: %m");
+  set_socket_buffer (fds[1]);
+
+  /* This is the !only_early test.  It is a late cancel test that has a sleep
+     in the main thread in an attempt to allow the child thread to reach and
+     block on the syscall.  The cancellation should happen with high
+     probability when the child thread blocked on the syscall, and that is
+     the intent of the test (syscall cancellation registration complete).  */
+  for (int i = 0; i < array_length (tests); i++)
+    {
+      if (tests[i].only_early)
+	continue;
+
+      xpthread_barrier_init (&barrier, NULL, 2);
+      /* Reset the counter for the cleanup handler.  */
+      cl_called = 0;
+
+      pthread_t thr = xpthread_create (0, tests[i].tf, (void *) 1L);
+      /* After this wait the threads cancellation handler is installed.  */
+      xpthread_barrier_wait (&barrier);
+
+      struct timespec ts = { .tv_sec = 0, .tv_nsec = 100000000 };
+      TEMP_FAILURE_RETRY (clock_nanosleep (CLOCK_REALTIME, 0, &ts, &ts));
+
+      xpthread_cancel (thr);
+
+      void *status = xpthread_join (thr);
+      TEST_VERIFY (status == PTHREAD_CANCELED);
+      TEST_COMPARE (cl_called, 1);
+
+      printf ("in-time cancel test of '%s' successful\n", tests[i].name);
+    }
+
+  /* This is a early cancel test that happens before the syscall is issued.
+     In this case there is no signal involved, pthread_cancel will just mark
+     the target thread canceled, since asynchronous mode is not set, and the
+     cancellable entrypoint will check if the thread is set as cancelled and
+     exit early.
+
+     Keep in mind that neither pthread_barrier_wait nor pthread_cleanup_push
+     act as cancellation entrypoints.  */
+  for (int i = 0; i < array_length (tests); i++)
+    {
+      xpthread_barrier_init (&barrier, NULL, 2);
+      /* Reset the counter for the cleanup handler.  */
+      cl_called = 0;
+
+      /* After this wait the cancellation handler is in place.  */
+      pthread_t thr = xpthread_create (0, tests[i].tf, NULL);
+
+      xpthread_cancel (thr);
+      xpthread_barrier_wait (&barrier);
+
+      void *status = xpthread_join (thr);
+      TEST_VERIFY (status == PTHREAD_CANCELED);
+      TEST_COMPARE (cl_called, 1);
+
+      printf ("early cancel test of '%s' successful\n", tests[i].name);
+    }
+
+  xpthread_barrier_destroy (&barrier);
+
+  return 0;
+}
+
+#include <support/test-driver.c>

debug/tst-read-chk-cancel.c

@@ -1,50 +0,0 @@
-/* Test that __read_chk is a cancellation point (BZ #29274)
-   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 <stdint.h>
-#include <support/xunistd.h>
-#include <support/xthread.h>
-
-static int pipe_fds[2];
-static pthread_barrier_t barrier;
-
-static void *
-read_thread (void *n)
-{
-  xpthread_barrier_wait (&barrier);
-  char c;
-  /* This call should be forwarded to __read_chk because the buffer size
-     is known, but the read length is non-constant.  */
-  if (read (pipe_fds[0], &c, (uintptr_t) n) != 1)
-    return (void *) -1L;
-  return 0;
-}
-
-static int
-do_test (void)
-{
-  xpthread_barrier_init (&barrier, 0, 2);
-  xpipe (pipe_fds);
-  pthread_t thr = xpthread_create (0, read_thread, (void *) 1L);
-  xpthread_barrier_wait (&barrier);
-  xpthread_cancel (thr);
-  xpthread_join (thr);
-  return 0;
-}
-
-#include <support/test-driver.c>