1  /* macros useful in interpreting size-related values in struct stat.
       2     Copyright (C) 1989, 1991-2023 Free Software Foundation, Inc.
       3  
       4     This program is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU General Public License as published by
       6     the Free Software Foundation, either version 3 of the License, or
       7     (at your option) any later version.
       8  
       9     This program 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
      12     GNU General Public License for more details.
      13  
      14     You should have received a copy of the GNU General Public License
      15     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      16  /*
      17     Macros defined by this file (s is an rvalue of type struct stat):
      18  
      19     DEV_BSIZE:       The device blocksize.  But use ST_NBLOCKSIZE instead.
      20     ST_BLKSIZE(s):   Preferred (in the sense of best performance) I/O blocksize
      21                      for the file, in bytes.
      22     ST_NBLOCKS(s):   Number of blocks in the file, including indirect blocks.
      23     ST_NBLOCKSIZE:   Size of blocks used when calculating ST_NBLOCKS.
      24   */
      25  #ifndef STAT_SIZE_H
      26  #define STAT_SIZE_H
      27  
      28  /* This file uses HAVE_SYS_PARAM_H, HAVE_STRUCT_STAT_ST_BLOCKS.  */
      29  #if !_GL_CONFIG_H_INCLUDED
      30   #error "Please include config.h first."
      31  #endif
      32  
      33  /* sys/param.h may define DEV_BSIZE */
      34  #if HAVE_SYS_PARAM_H
      35  # include <sys/param.h>
      36  #endif
      37  
      38  
      39  /* Get or fake the disk device blocksize.
      40     Usually defined by sys/param.h (if at all).  */
      41  #if !defined DEV_BSIZE && defined BSIZE
      42  # define DEV_BSIZE BSIZE
      43  #endif
      44  #if !defined DEV_BSIZE && defined BBSIZE /* SGI sys/param.h */
      45  # define DEV_BSIZE BBSIZE
      46  #endif
      47  #ifndef DEV_BSIZE
      48  # define DEV_BSIZE 4096
      49  #endif
      50  
      51  
      52  
      53  /* Extract or fake data from a 'struct stat'.
      54     ST_BLKSIZE: Preferred I/O blocksize for the file, in bytes.
      55     ST_NBLOCKS: Number of blocks in the file, including indirect blocks.
      56     ST_NBLOCKSIZE: Size of blocks used when calculating ST_NBLOCKS.  */
      57  #ifndef HAVE_STRUCT_STAT_ST_BLOCKS
      58  # define ST_BLKSIZE(statbuf) DEV_BSIZE
      59    /* coreutils' fileblocks.c also uses BSIZE.  */
      60  # if defined _POSIX_SOURCE || !defined BSIZE
      61  #  define ST_NBLOCKS(statbuf) \
      62    ((statbuf).st_size / ST_NBLOCKSIZE + ((statbuf).st_size % ST_NBLOCKSIZE != 0))
      63  # else
      64     /* This definition calls st_blocks, which is in the fileblocks module. */
      65  #  define ST_NBLOCKS(statbuf) \
      66    (S_ISREG ((statbuf).st_mode) || S_ISDIR ((statbuf).st_mode) ? \
      67     st_blocks ((statbuf).st_size) : 0)
      68  # endif
      69  #else
      70  /* When running 'rsh hpux11-system cat any-file', cat would
      71     determine that the output stream had an st_blksize of 2147421096.
      72     Conversely st_blksize can be 2 GiB (or maybe even larger) with XFS
      73     on 64-bit hosts.  Somewhat arbitrarily, limit the "optimal" block
      74     size to SIZE_MAX / 8 + 1.  (Dividing SIZE_MAX by only 4 wouldn't
      75     suffice, since "cat" sometimes multiplies the result by 4.)  If
      76     anyone knows of a system for which this limit is too small, please
      77     report it as a bug in this code.  */
      78  # define ST_BLKSIZE(statbuf) ((0 < (statbuf).st_blksize \
      79                                 && (statbuf).st_blksize <= ((size_t)-1) / 8 + 1) \
      80                                ? (statbuf).st_blksize : DEV_BSIZE)
      81  # if defined hpux || defined __hpux__ || defined __hpux
      82    /* HP-UX counts st_blocks in 1024-byte units.
      83       This loses when mixing HP-UX and BSD file systems with NFS.  */
      84  #  define ST_NBLOCKSIZE 1024
      85  # endif
      86  #endif
      87  
      88  #ifndef ST_NBLOCKS
      89  # define ST_NBLOCKS(statbuf) ((statbuf).st_blocks)
      90  #endif
      91  
      92  #ifndef ST_NBLOCKSIZE
      93  # ifdef S_BLKSIZE
      94  #  define ST_NBLOCKSIZE S_BLKSIZE
      95  # else
      96  #  define ST_NBLOCKSIZE 512
      97  # endif
      98  #endif
      99  
     100  #endif /* STAT_SIZE_H */