glibc/sysdeps/unix/sysv/linux/futimes.c

138 lines
3.9 KiB
C

/* futimes -- change access and modification times of open file. Linux version.
Copyright (C) 2002-2014 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 <errno.h>
#include <sysdep.h>
#include <string.h>
#include <time.h>
#include <utime.h>
#include <sys/time.h>
#include <_itoa.h>
#include <fcntl.h>
#include <kernel-features.h>
#if defined __NR_utimensat && !defined __ASSUME_UTIMENSAT
static int miss_utimensat;
#endif
/* Change the access time of the file associated with FD to TVP[0] and
the modification time of FILE to TVP[1].
Starting with 2.6.22 the Linux kernel has the utimensat syscall which
can be used to implement futimes. Earlier kernels have no futimes()
syscall so we use the /proc filesystem. */
int
__futimes (int fd, const struct timeval tvp[2])
{
/* The utimensat system call expects timespec not timeval. */
struct timespec ts[2];
if (tvp != NULL)
{
if (tvp[0].tv_usec < 0 || tvp[0].tv_usec >= 1000000
|| tvp[1].tv_usec < 0 || tvp[1].tv_usec >= 1000000)
{
__set_errno (EINVAL);
return -1;
}
TIMEVAL_TO_TIMESPEC (&tvp[0], &ts[0]);
TIMEVAL_TO_TIMESPEC (&tvp[1], &ts[1]);
}
#ifdef __ASSUME_UTIMENSAT
return INLINE_SYSCALL (utimensat, 4, fd, NULL, tvp ? &ts : NULL, 0);
#else
int result;
# ifdef __NR_utimensat
if (!__builtin_expect (miss_utimensat, 0))
{
result = INLINE_SYSCALL (utimensat, 4, fd, NULL, tvp ? &ts : NULL, 0);
if (__builtin_expect (result, 0) != -1 || errno != ENOSYS)
return result;
miss_utimensat = 1;
}
# endif
static const char selffd[] = "/proc/self/fd/";
char fname[sizeof (selffd) + 3 * sizeof (int)];
fname[sizeof (fname) - 1] = '\0';
char *cp = _itoa_word ((unsigned int) fd, fname + sizeof (fname) - 1, 10, 0);
cp = memcpy (cp - sizeof (selffd) + 1, selffd, sizeof (selffd) - 1);
# ifdef __NR_utimes
result = INLINE_SYSCALL (utimes, 2, cp, tvp);
# ifndef __ASSUME_UTIMES
if (result == -1 && errno == ENOSYS)
# endif
# endif
{
/* The utimes() syscall does not exist or is not available in the
used kernel. Use utime(). For this we have to convert to the
data format utime() expects. */
# ifndef __ASSUME_UTIMES
struct utimbuf buf;
struct utimbuf *times;
if (tvp != NULL)
{
times = &buf;
buf.actime = tvp[0].tv_sec;
buf.modtime = tvp[1].tv_sec;
}
else
times = NULL;
result = INLINE_SYSCALL (utime, 2, cp, times);
# endif
}
if (result == -1)
/* Check for errors that result from failing to find /proc.
This means we can't do futimes at all, so return ENOSYS
rather than some confusing error. */
switch (errno)
{
case EACCES:
if (tvp == NULL) /* Could be a path problem or a file problem. */
break;
/*FALLTHROUGH*/
case ELOOP:
case ENAMETOOLONG:
case ENOTDIR:
__set_errno (ENOSYS);
break;
case ENOENT:
/* Validate the file descriptor by letting fcntl set errno to
EBADF if it's bogus. Otherwise it's a /proc issue. */
# if !defined __NR_fcntl && defined __NR_fcntl64
# define __NR_fcntl __NR_fcntl64
# endif
if (INLINE_SYSCALL (fcntl, 3, fd, F_GETFD, 0) != -1)
__set_errno (ENOSYS);
break;
}
return result;
#endif
}
weak_alias (__futimes, futimes)