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551101e824
AT_EMPTY_PATH is a requirement to implement fstat over fstatat, however it does not prevent the kernel to read the path argument. It is not an issue, but on x86-64 with SMAP-capable CPUs the kernel is forced to perform expensive user memory access. After that regular lookup is performed which adds even more overhead. Instead, issue the fstat syscall directly on LFS fstat implementation (32 bit architectures will still continue to use statx, which is required to have 64 bit time_t support). it should be even a small performance gain on non x86_64, since there is no need to handle the path argument. Checked on x86_64-linux-gnu.
98 lines
2.6 KiB
C
98 lines
2.6 KiB
C
/* Get file status. Linux version.
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Copyright (C) 2020-2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#define __fstat __redirect___fstat
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#define fstat __redirect_fstat
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#include <sys/stat.h>
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#undef __fstat
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#undef fstat
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#include <fcntl.h>
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#include <internal-stat.h>
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#include <errno.h>
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int
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__fstat64_time64 (int fd, struct __stat64_t64 *buf)
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{
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#if !FSTATAT_USE_STATX
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# if XSTAT_IS_XSTAT64
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# ifdef __NR_fstat
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/* 64-bit kABI, e.g. aarch64, ia64, powerpc64*, s390x, riscv64, and
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x86_64. */
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return INLINE_SYSCALL_CALL (fstat, fd, buf);
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# elif defined __NR_fstat64
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# if STAT64_IS_KERNEL_STAT64
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/* 64-bit kABI outlier, e.g. alpha */
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return INLINE_SYSCALL_CALL (fstat64, fd, buf);
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# else
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/* 64-bit kABI outlier, e.g. sparc64. */
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struct kernel_stat64 kst64;
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int r = INLINE_SYSCALL_CALL (fstat64, fd, &kst64);
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if (r == 0)
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__cp_stat64_kstat64 (buf, &kst64);
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return r;
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# endif /* STAT64_IS_KERNEL_STAT64 */
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# endif
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# else /* XSTAT_IS_XSTAT64 */
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/* 64-bit kabi outlier, e.g. mips64 and mips64-n32. */
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struct kernel_stat kst;
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int r = INLINE_SYSCALL_CALL (fstat, fd, &kst);
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if (r == 0)
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__cp_kstat_stat64_t64 (&kst, buf);
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return r;
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# endif
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#else /* !FSTATAT_USE_STATX */
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/* All kABIs with non-LFS support and with old 32-bit time_t support
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e.g. arm, csky, i386, hppa, m68k, microblaze, nios2, sh, powerpc32,
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and sparc32. */
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if (fd < 0)
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{
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__set_errno (EBADF);
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return -1;
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}
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return __fstatat64_time64 (fd, "", buf, AT_EMPTY_PATH);
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#endif
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}
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#if __TIMESIZE != 64
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hidden_def (__fstat64_time64)
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int
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__fstat64 (int fd, struct stat64 *buf)
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{
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if (fd < 0)
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{
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__set_errno (EBADF);
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return -1;
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}
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struct __stat64_t64 st_t64;
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return __fstat64_time64 (fd, &st_t64)
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?: __cp_stat64_t64_stat64 (&st_t64, buf);
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}
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#endif
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#undef __fstat
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#undef fstat
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hidden_def (__fstat64)
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weak_alias (__fstat64, fstat64)
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#if XSTAT_IS_XSTAT64
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strong_alias (__fstat64, __fstat)
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weak_alias (__fstat64, fstat)
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#endif
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