linux: Only use 64-bit syscall if required for mq_timedreceive

For !__ASSUME_TIME64_SYSCALLS there is no need to issue a 64-bit syscall
if the provided timeout fits in a 32-bit one.  The 64-bit usage should
be rare since the timeout is a relative one.

Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel
(with and without --enable-kernel=5.1) and on x86_64-linux-gnu.

Reviewed-by: Lukasz Majewski <lukma@denx.de>

diff --git a/rt/Makefile b/rt/Makefile
index 329db09c32fded1c7b2c837f2df8d31e0f5a7ad7..6c7728a3183cc313ec3bb1f31abdb17e53677ffb 100644 (file)
--- a/rt/Makefile
+++ b/rt/Makefile
@@ -68,7 +68,8 @@ tests := tst-shm tst-timer tst-timer2 \
         tst-mqueue5 tst-mqueue6 tst-mqueue7 tst-mqueue8 tst-mqueue9 \
         tst-timer3 tst-timer4 tst-timer5 \
         tst-cpuclock2 tst-cputimer1 tst-cputimer2 tst-cputimer3 \
-        tst-shm-cancel
+        tst-shm-cancel \
+        tst-mqueue10
 tests-internal := tst-timer-sigmask
 
 tests-time64 := \
@@ -78,6 +79,7 @@ tests-time64 := \
   tst-mqueue2-time64 \
   tst-mqueue4-time64 \
   tst-mqueue8-time64 \
+  tst-mqueue10-time64 \
   tst-timer4-time64
 
 extra-libs := librt

diff --git a/rt/tst-mqueue10-time64.c b/rt/tst-mqueue10-time64.c
new file mode 100644 (file)
index 0000000..2c8a4ae
--- /dev/null
+++ b/rt/tst-mqueue10-time64.c
@@ -0,0 +1 @@
+#include "tst-mqueue10.c"

diff --git a/rt/tst-mqueue10.c b/rt/tst-mqueue10.c
new file mode 100644 (file)
index 0000000..7fb53a1
--- /dev/null
+++ b/rt/tst-mqueue10.c
@@ -0,0 +1,62 @@
+/* Check for large timeout with mq_timedsend and mq_timedreceive.
+   Copyright (C) 2021 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 <mqueue.h>
+#include <stdio.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/temp_file.h>
+#include <unistd.h>
+
+static char name[sizeof "/tst-mqueue2-" + INT_BUFSIZE_BOUND (pid_t)];
+
+static void
+do_cleanup (void)
+{
+  mq_unlink (name);
+}
+#define CLEANUP_HANDLER        do_cleanup
+
+static int
+do_test (void)
+{
+  snprintf (name, sizeof (name), "/tst-mqueue2-%u", getpid ());
+
+  char msg[8] = { 0x55 };
+
+  struct mq_attr attr = { .mq_maxmsg = 1, .mq_msgsize = sizeof (msg) };
+  mqd_t q = mq_open (name, O_CREAT | O_EXCL | O_RDWR, 0600, &attr);
+  TEST_VERIFY_EXIT (q != (mqd_t) -1);
+
+  struct timespec ts = { TYPE_MAXIMUM (time_t), 0 };
+
+  {
+    timer_t timer = support_create_timer (0, 100000000, false, NULL);
+    TEST_COMPARE (mq_timedreceive (q, msg, sizeof (msg), NULL, &ts), -1);
+    TEST_VERIFY (errno == EINTR || errno == EOVERFLOW);
+    support_delete_timer (timer);
+  }
+
+  mq_unlink (name);
+
+  return 0;
+}
+
+#include <support/test-driver.c>

diff --git a/sysdeps/unix/sysv/linux/mq_timedreceive.c b/sysdeps/unix/sysv/linux/mq_timedreceive.c
index eb948ccc1820eeeb1e18291018d04e938ab5c34b..1a7b7a9c1123f86616e8c85739d3998ed0a0fedd 100644 (file)
--- a/sysdeps/unix/sysv/linux/mq_timedreceive.c
+++ b/sysdeps/unix/sysv/linux/mq_timedreceive.c
@@ -29,30 +29,33 @@ __mq_timedreceive_time64 (mqd_t mqdes, char *__restrict msg_ptr, size_t msg_len,
 #ifndef __NR_mq_timedreceive_time64
 # define __NR_mq_timedreceive_time64 __NR_mq_timedreceive
 #endif
-  int ret = SYSCALL_CANCEL (mq_timedreceive_time64, mqdes, msg_ptr, msg_len,
-                            msg_prio, abs_timeout);
 
-#ifndef __ASSUME_TIME64_SYSCALLS
-  if (ret == 0 || errno != ENOSYS)
-    return ret;
+#ifdef __ASSUME_TIME64_SYSCALLS
+  return SYSCALL_CANCEL (mq_timedreceive_time64, mqdes, msg_ptr, msg_len,
+                        msg_prio, abs_timeout);
+#else
+  bool need_time64 = abs_timeout != NULL
+                    && !in_time_t_range (abs_timeout->tv_sec);
+  if (need_time64)
+    {
+      int r = SYSCALL_CANCEL (mq_timedreceive_time64, mqdes, msg_ptr, msg_len,
+                             msg_prio, abs_timeout);
+      if (r == 0 || errno != ENOSYS)
+       return r;
+      __set_errno (EOVERFLOW);
+      return -1;
+    }
 
-  struct timespec ts32;
+  struct timespec ts32, *pts32 = NULL;
   if (abs_timeout != NULL)
     {
-      if (! in_time_t_range (abs_timeout->tv_sec))
-        {
-          __set_errno (EOVERFLOW);
-          return -1;
-        }
-
       ts32 = valid_timespec64_to_timespec (*abs_timeout);
+      pts32 = &ts32;
     }
 
-  ret = SYSCALL_CANCEL (mq_timedreceive, mqdes, msg_ptr, msg_len, msg_prio,
-                       abs_timeout != NULL ? &ts32 : NULL);
+  return SYSCALL_CANCEL (mq_timedreceive, mqdes, msg_ptr, msg_len, msg_prio,
+                        pts32);
 #endif
-
-  return ret;
 }
 
 #if __TIMESIZE != 64