glibc/sysdeps/unix/sysv/linux/fxstatat.c
Adhemerval Zanella 6073bae64c linux: Disentangle fstatat from fxstatat
It implements all the required syscall for the all Linux kABIS on
fstatat{64} instead of calling fxstatat{64}.

On non-LFS implementation, it handles 3 cases:

  1. New kABIs which uses generic pre 64-bit time Linux ABI (csky and
     nios): it issues __NR_fstat64 plus handle the overflow on st_ino,
     st_size, or st_blocks.

  2. Old KABIs with old non-LFS support (arm, i386, hppa, m68k,
     microblaze, mips32, s390, sh, powerpc, and sparc32): it issues
     __NR_fstatat64 and convert the result to struct stat.

  3. 64-bit kABI outliers (mips64 and mips64-n32): it issues
     __NR_newfstatat and convert the result to struct stat.

The generic LFS implementation handles multiple cases:

  1. XSTAT_IS_XSTAT64 being 1:

    1.1. 64-bit kABI (aarch64, ia64, powerpc64*, s390x, riscv64, and
         x86_64): it issues __NR_newfstatat.

    1.2. 64-bit kABI outlier (alpha): it issues __NR_fstatat64.

    1.3. 64-bit kABI outlier where struct stat64 does not match kernel
         one (sparc64): it issues __NR_fstatat64 and convert the result
         to struct stat64.

    1.4. 32-bit kABI with default 64-bit time_t (arc, riscv32): it
         issues __NR_statx and convert the result to struct stat64.

  2. Old ABIs with XSTAT_IS_XSTAT64 being 0:

    2.1. All kABIs with non-LFS support (arm, csky, i386, hppa, m68k,
         microblaze, nios2, sh, powerpc32, and sparc32): it issues
         __NR_fstatat64.

    2.2. 64-bit kABI outliers (mips64 and mips64-n32): it issues
         __NR_newfstatat and convert the result to struct stat64.

It allows to remove all the hidden definitions from the {f,l}xstat{64}
(some are still kept because Hurd requires it).

Checked with a build for all affected ABIs. I also checked on x86_64,
i686, powerpc, powerpc64le, sparcv9, sparc64, s390, and s390x.

Reviewed-by: Lukasz Majewski <lukma@denx.de>
2020-10-09 17:02:06 -03:00

50 lines
1.7 KiB
C

/* fxstatat used on fstatat, Linux implementation.
Copyright (C) 2005-2020 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 <sys/stat.h>
#include <fcntl.h>
#include <kernel_stat.h>
#include <sysdep.h>
#if !XSTAT_IS_XSTAT64
# include <xstatconv.h>
# include <xstatover.h>
/* Get information about the file FD in BUF. */
int
__fxstatat (int vers, int fd, const char *file, struct stat *st, int flag)
{
#if STAT_IS_KERNEL_STAT
/* New kABIs which uses generic pre 64-bit time Linux ABI, e.g.
csky, nios2 */
if (vers == _STAT_VER_KERNEL)
{
int r = INLINE_SYSCALL_CALL (fstatat64, fd, file, st, flag);
return r ?: stat_overflow (st);
}
return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
#else
/* Old kABIs with old non-LFS support, e.g. arm, i386, hppa, m68k, mips32,
microblaze, s390, sh, powerpc32, and sparc32. */
struct stat64 st64;
int r = INLINE_SYSCALL_CALL (fstatat64, fd, file, &st64, flag);
return r ?: __xstat32_conv (vers, &st64, st);
#endif
}
#endif /* XSTAT_IS_XSTAT64 */