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* [PATCH v3] debug: test for more required cacellation points (BZ# 29274)
@ 2022-07-18 16:46 Adhemerval Zanella
  2022-07-21 21:23 ` Carlos O'Donell
  0 siblings, 1 reply; 4+ messages in thread
From: Adhemerval Zanella @ 2022-07-18 16:46 UTC (permalink / raw)
  To: libc-alpha, Carlos O'Donell; +Cc: Andreas Schwab

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 aarch64-linux-gnu.

Co-authored-by: Andreas Schwab <schwab@suse.de>
---
 debug/Makefile              |   6 +-
 debug/tst-chk-cancel.c      | 269 ++++++++++++++++++++++++++++++++++++
 debug/tst-read-chk-cancel.c |  50 -------
 3 files changed, 272 insertions(+), 53 deletions(-)
 create mode 100644 debug/tst-chk-cancel.c
 delete mode 100644 debug/tst-read-chk-cancel.c

diff --git a/debug/Makefile b/debug/Makefile
index 456b349c4d..99cdf3221b 100644
--- a/debug/Makefile
+++ b/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)
diff --git a/debug/tst-chk-cancel.c b/debug/tst-chk-cancel.c
new file mode 100644
index 0000000000..f9ebc4a3f4
--- /dev/null
+++ b/debug/tst-chk-cancel.c
@@ -0,0 +1,269 @@
+/* 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 test is the early cancel version of the first test, and the intent
+     is to have the cancellation happen at one of two regions:
+
+     1. Before the cancellable syscall registers cancellation.
+     2. After the cancellable syscall registers cancellation.
+
+     This test will exercise if syscall cancellation registration is an atomic
+     operation or not since the transition from the regions is designed to be
+     atomic.
+
+     We can not control when the cancellation happens, but it will happen in
+     one of the two regions.  The first test (the !only_early version)
+     attempts to test the second region, while this test attempts to test the
+     first regiont and the transition with some probability.  */
+  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>
diff --git a/debug/tst-read-chk-cancel.c b/debug/tst-read-chk-cancel.c
deleted file mode 100644
index 7e06afb596..0000000000
--- a/debug/tst-read-chk-cancel.c
+++ /dev/null
@@ -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>
-- 
2.34.1


^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-08-29 14:02 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-07-18 16:46 [PATCH v3] debug: test for more required cacellation points (BZ# 29274) Adhemerval Zanella
2022-07-21 21:23 ` Carlos O'Donell
2022-07-26 19:10   ` Adhemerval Zanella Netto
2022-08-29 14:02     ` Carlos O'Donell

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