glibc/io/statx_generic.c
Florian Weimer 5dad6ffbb2 <sys/stat.h>: Use Linux UAPI header for statx if available and useful
This will automatically import new STATX_* constants.  It also avoids
a conflict between <sys/stat.h> and <linux/stat.h>.
2019-06-12 13:04:43 +02:00

91 lines
3.1 KiB
C

/* Generic implementation of statx based on fstatat64.
Copyright (C) 2018-2019 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 <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
/* Obtain the original definition of struct statx. */
#undef __statx_defined
#define statx original_statx
#include <bits/types/struct_statx.h>
#undef statx
static inline struct statx_timestamp
statx_convert_timestamp (struct timespec tv)
{
return (struct statx_timestamp) { tv.tv_sec, tv.tv_nsec };
}
/* Approximate emulation of statx. This will always fill in
POSIX-mandated attributes even if the underlying file system does
not actually support it (for example, GID and UID on file systems
without UNIX-style permissions). */
static __attribute__ ((unused)) int
statx_generic (int fd, const char *path, int flags,
unsigned int mask, struct statx *buf)
{
/* Flags which need to be cleared before passing them to
fstatat64. */
static const int clear_flags = AT_STATX_SYNC_AS_STAT;
/* Flags supported by our emulation. */
static const int supported_flags
= AT_EMPTY_PATH | AT_NO_AUTOMOUNT | AT_SYMLINK_NOFOLLOW | clear_flags;
if (__glibc_unlikely ((flags & ~supported_flags) != 0))
{
__set_errno (EINVAL);
return -1;
}
struct stat64 st;
int ret = __fstatat64 (fd, path, &st, flags & ~clear_flags);
if (ret != 0)
return ret;
/* The interface is defined in such a way that unused (padding)
fields have to be cleared. STATX_BASIC_STATS corresponds to the
data which is available via fstatat64. */
struct original_statx obuf =
{
.stx_mask = STATX_BASIC_STATS,
.stx_blksize = st.st_blksize,
.stx_nlink = st.st_nlink,
.stx_uid = st.st_uid,
.stx_gid = st.st_gid,
.stx_mode = st.st_mode,
.stx_ino = st.st_ino,
.stx_size = st.st_size,
.stx_blocks = st.st_blocks,
.stx_atime = statx_convert_timestamp (st.st_atim),
.stx_ctime = statx_convert_timestamp (st.st_ctim),
.stx_mtime = statx_convert_timestamp (st.st_mtim),
.stx_rdev_major = major (st.st_rdev),
.stx_rdev_minor = minor (st.st_rdev),
.stx_dev_major = major (st.st_dev),
.stx_dev_minor = minor (st.st_dev),
};
_Static_assert (sizeof (*buf) >= sizeof (obuf), "struct statx size");
memcpy (buf, &obuf, sizeof (obuf));
return 0;
}