sysdeps/unix/sysv/linux/posix_fadvise.c

   1 /* Copyright (C) 2003-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <fcntl.h>
  20 #include <sysdep.h>
  21
  22 /* Advice the system about the expected behaviour of the application with
  23    respect to the file associated with FD.  */
  24
  25 #ifndef __OFF_T_MATCHES_OFF64_T
  26
  27 /* Default implementation will use __NR_fadvise64 with expected argument
  28    positions (for instance i386 and powerpc32 that uses __ALIGNMENT_ARG).
  29
  30    Second option will be used by arm which define __NR_arm_fadvise64_64
  31    (redefined to __NR_fadvise64_64 in kernel-features.h) that behaves as
  32    __NR_fadvise64_64 (without the alignment argument required for the ABI).
  33
  34    Third option will be used by mips o32.  Mips will use a 7 argument
  35    syscall with __NR_fadvise64.
  36
  37    s390 implements fadvice64_64 using a specific struct with arguments
  38    packed inside.  This is the only implementation handled in arch-specific
  39    code.  */
  40
  41 int
  42 posix_fadvise (int fd, off_t offset, off_t len, int advise)
  43 {
  44 # if defined (__NR_fadvise64) && !defined (__ASSUME_FADVISE64_AS_64_64)
  45   int ret = INTERNAL_SYSCALL_CALL (fadvise64, fd,
  46                                    __ALIGNMENT_ARG SYSCALL_LL (offset),
  47                                    len, advise);
  48 # else
  49 #  ifdef __ASSUME_FADVISE64_64_6ARG
  50   int ret = INTERNAL_SYSCALL_CALL (fadvise64_64, fd, advise,
  51                                    SYSCALL_LL (offset), SYSCALL_LL (len));
  52 #  else
  53
  54 #   ifndef __NR_fadvise64_64
  55 #    define __NR_fadvise64_64 __NR_fadvise64
  56 #   endif
  57
  58   int ret = INTERNAL_SYSCALL_CALL (fadvise64_64, fd,
  59                                    __ALIGNMENT_ARG SYSCALL_LL (offset),
  60                                    SYSCALL_LL (len), advise);
  61 #  endif
  62 # endif
  63   if (INTERNAL_SYSCALL_ERROR_P (ret))
  64     return INTERNAL_SYSCALL_ERRNO (ret);
  65   return 0;
  66 }
  67 #endif /* __OFF_T_MATCHES_OFF64_T  */