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linux: Consolidate fxstatat{64}

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The LFS support is implemented on fxstat64.c, instead of fxstat.c for
64-bit architectures.  The fxstatat.c implements the non-LFS and it is
a no-op for !XSTAT_IS_XSTAT64.

The generic non-LFS implementation handles two cases:

  1. New kABIs which uses generic pre 64-bit time Linux ABI (csky and
     nios): it issues __NR_fstatat64 plus handle the overflow on st_ino,
     st_size, or st_blocks.  It only handles _STAT_VER_KERNEL.

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

Also non-LFS mips64 is an outlier and it has its own implementation
since _STAT_VER_LINUX requires a different conversion function (it
uses the kernel_stat as the sysissues argument since its exported ABI
is different than the kernel one for both non-LFS and LFS
implementation).

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 for _STAT_VER_KERNEL or
         _STAT_VER_LINUX.

    1.2. 64-bit kABI outlier (sparc64): it issuess fstatat64 with a
         temporary stat64 and convert to output stat64 based on the
         input version (and using a sparc64 specific __xstat32_conv).

    1.3. New 32-bit kABIs with only 64-bit time_t support (arc and
	 riscv32): it issues __NR_statx and covert to struct stat64.

  2. Old ABIs with XSTAT_IS_XSTAT64 being 0 (arm, csky, i386, hppa, m68k,
     microblaze, mips32, nios2, sh, powerpc32, and sparc32): it issues
     __NR_fstat64.

Also, two special cases requires specific implementations:

  1. alpha: it uses the __NR_fstatat64 syscall instead.

  2. mips64: as for non-LFS implementation its ABIs differ from
     glibc exported one, which requires an specific conversion
     function to handle the kernel_stat.

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>
This commit is contained in:
Adhemerval Zanella
2020-07-15 18:05:52 +00:00
parent 5febe6a38f
commit 5f85cc2f47
23 changed files with 93 additions and 302 deletions
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55
sysdeps/unix/sysv/linux/fxstatat.c
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@ -1,4 +1,5 @@
/* Copyright (C) 2005-2020 Free Software Foundation, Inc.
/* 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
@ -15,48 +16,36 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* Ho hum, if fxstatat == fxstatat64 we must get rid of the prototype or gcc
will complain since they don't strictly match. */
#define __fxstatat64 __fxstatat64_disable
#include <errno.h>
#include <fcntl.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <kernel_stat.h>
#include <sysdep.h>
#include <sys/syscall.h>
#include <xstatconv.h>
#if !XSTAT_IS_XSTAT64
# include <xstatconv.h>
# include <xstatover.h>
/* Get information about the file NAME in BUF. */
/* Get information about the file FD in BUF. */
int
__fxstatat (int vers, int fd, const char *file, struct stat *st, int flag)
{
int result;
#if STAT_IS_KERNEL_STAT
# define kst (*st)
#else
struct kernel_stat kst;
#endif
result = INTERNAL_SYSCALL_CALL (newfstatat, fd, file, &kst, flag);
if (!__glibc_likely (INTERNAL_SYSCALL_ERROR_P (result)))
/* New kABIs which uses generic pre 64-bit time Linux ABI, e.g.
csky, nios2 */
if (vers == _STAT_VER_KERNEL)
{
#if STAT_IS_KERNEL_STAT
return 0;
#else
return __xstat_conv (vers, &kst, st);
#endif
int r = INLINE_SYSCALL_CALL (fstatat64, fd, file, st, flag);
return r ?: stat_overflow (st);
}
return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (result));
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
}
libc_hidden_def (__fxstatat)
#if XSTAT_IS_XSTAT64
# undef __fxstatat64
strong_alias (__fxstatat, __fxstatat64);
libc_hidden_def (__fxstatat64)
#endif
#endif /* XSTAT_IS_XSTAT64 */