glibc/sysdeps/unix/sysv/linux/futimes.c
Lukasz Majewski f072671cf5 y2038: linux: Provide __futimes64 implementation
This patch provides new __futimes64 explicit 64 bit function for setting file's
64 bit attributes for access and modification time (by specifying file
descriptor number).

Internally, the __utimensat64_helper function is used. This patch is necessary
for having architectures with __WORDSIZE == 32 Y2038 safe.

Moreover, a 32 bit version - __futimes has been refactored to internally use
__futimes64.

The __futimes is now supposed to be used on systems still supporting 32
bit time (__TIMESIZE != 64) - hence the necessary conversion of struct timeval
to 64 bit struct __timeval64.

The check if struct timevals' usec fields are in the range between 0 and 1000000
has been removed as Linux kernel performs it internally in the implementation
of utimensat (the conversion between struct __timeval64 and __timespec64 is not
relevant for this particular check).

Last but not least, checks for tvp{64} not being NULL have been preserved from
the original code as some legacy user space programs may rely on it.

Build tests:
./src/scripts/build-many-glibcs.py glibcs

Run-time tests:
- Run specific tests on ARM/x86 32bit systems (qemu):
  https://github.com/lmajewski/meta-y2038 and run tests:
  https://github.com/lmajewski/y2038-tests/commits/master

Above tests were performed with Y2038 redirection applied as well as without to
test the proper usage of both __futimes64 and __futimes.
2020-03-09 10:26:46 +01:00

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1.7 KiB
C

/* futimes -- change access and modification times of open file. Linux version.
Copyright (C) 2002-2020 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
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <time.h>
/* Change the access time of the file associated with FD to TVP[0] and
the modification time of FILE to TVP[1]. */
int
__futimes64 (int fd, const struct __timeval64 tvp64[2])
{
/* The utimensat system call expects timespec not timeval. */
struct __timespec64 ts64[2];
if (tvp64 != NULL)
{
ts64[0] = timeval64_to_timespec64 (tvp64[0]);
ts64[1] = timeval64_to_timespec64 (tvp64[1]);
}
return __utimensat64_helper (fd, NULL, tvp64 ? &ts64[0] : NULL, 0);
}
#if __TIMESIZE != 64
libc_hidden_def (__futimes64)
int
__futimes (int fd, const struct timeval tvp[2])
{
struct __timeval64 tv64[2];
if (tvp != NULL)
{
tv64[0] = valid_timeval_to_timeval64 (tvp[0]);
tv64[1] = valid_timeval_to_timeval64 (tvp[1]);
}
return __futimes64 (fd, tvp ? &tv64[0] : NULL);
}
#endif
weak_alias (__futimes, futimes)