[RFC v6 04/23] linux: Use 32-bit time_t for itimerval

[Alistair Francis <alistair dot francis at wdc dot com>]

The Linux kernel expects itimerval to use a 32-bit time_t, even on archs
with a 64-bit time_t (like RV32). To address this let's convert
itimerval to/from 32-bit and 64-bit to ensure the kernel always gets
a 32-bit time_t.

This means that all 32-bit architectures with a 64-bit time_t will be
able to use this generic implementation.

This code is bsaed on similar code in alpha, but adjusted to pass the
32-bit time_t to the kernel.

We can't directly call the __getitimer/__setitimer functions as they
expect a struct itimerval but we need to pass in a struct itimerval32.
---
 .../linux/generic/wordsize-32/getitimer.c     | 42 +++++++++++++++
 .../linux/generic/wordsize-32/setitimer.c     | 53 +++++++++++++++++++
 .../linux/generic/wordsize-32/tv32-compat.h   | 35 ++++++++++++
 3 files changed, 130 insertions(+)
 create mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c
 create mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c
 create mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h

diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c
new file mode 100644
index 0000000000..b279acbc2e
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/getitimer.c
@@ -0,0 +1,42 @@
+/* getitimer -- Get the state of an interval timer.  Linux/RV32/tv32 version.
+   Copyright (C) 2020 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sys/time.h>
+#include <sysdep.h>
+#include <tv32-compat.h>
+
+int
+__getitimer (__itimer_which_t which, struct itimerval *curr_value)
+{
+#if __TIMESIZE == 64
+  struct itimerval32 curr_value_32;
+  if (INLINE_SYSCALL_CALL (getitimer, which, &curr_value_32) == -1)
+    return -1;
+
+  /* Write all fields of 'curr_value' regardless of overflow.  */
+  curr_value->it_interval
+    = valid_timeval_long_to_timeval64 (curr_value_32.it_interval);
+  curr_value->it_value
+    = valid_timeval_long_to_timeval64 (curr_value_32.it_value);
+  return 0;
+#else
+  return INLINE_SYSCALL_CALL (getitimer, which, curr_value);
+#endif
+}
+
+weak_alias (__getitimer, getitimer)
diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c
new file mode 100644
index 0000000000..807683ccae
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/setitimer.c
@@ -0,0 +1,53 @@
+/* getitimer -- Get the state of an interval timer.  Linux/RV32/tv32 version.
+   Copyright (C) 2020 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sys/time.h>
+#include <sysdep.h>
+#include <tv32-compat.h>
+
+int
+__setitimer (__itimer_which_t which,
+             const struct itimerval *restrict new_value,
+             struct itimerval *restrict old_value)
+{
+#if __TIMESIZE == 64
+  struct itimerval32 new_value_32;
+  new_value_32.it_interval
+    = valid_timeval64_to_timeval_long (new_value->it_interval);
+  new_value_32.it_value
+    = valid_timeval64_to_timeval_long (new_value->it_value);
+
+  if (old_value == NULL)
+    return INLINE_SYSCALL_CALL (setitimer, which, &new_value_32, NULL);
+
+  struct itimerval32 old_value_32;
+  if (INLINE_SYSCALL_CALL (setitimer, which, &new_value_32, &old_value_32) == -1)
+    return -1;
+
+  /* Write all fields of 'old_value' regardless of overflow.  */
+  old_value->it_interval
+     = valid_timeval_long_to_timeval64 (old_value_32.it_interval);
+  old_value->it_value
+     = valid_timeval_long_to_timeval64 (old_value_32.it_value);
+  return 0;
+#else
+  return INLINE_SYSCALL_CALL (setitimer, which, new_value, old_value);
+#endif
+}
+
+weak_alias (__setitimer, setitimer)
diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h b/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
new file mode 100644
index 0000000000..aa960a6632
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/generic/wordsize-32/tv32-compat.h
@@ -0,0 +1,35 @@
+/* Compatibility definitions for `struct timeval' with 32-bit time_t.
+   Copyright (C) 2020 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
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _TV32_COMPAT_H
+#define _TV32_COMPAT_H 1
+
+#include <features.h>
+
+#include <bits/types.h>
+#include <bits/types/time_t.h>
+#include <bits/types/struct_timeval.h>
+
+/* Structures containing 'struct timeval' with 32-bit time_t.  */
+struct itimerval32
+{
+  struct __timeval_long it_interval;
+  struct __timeval_long it_value;
+};
+
+#endif /* tv32-compat.h */
-- 
2.24.1