1  /* macros useful in interpreting size-related values in struct stat.
       2     Copyright (C) 1989, 1991-2022 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  /* sys/param.h may define DEV_BSIZE */
      29  #if HAVE_SYS_PARAM_H
      30  # include <sys/param.h>
      31  #endif
      32  
      33  
      34  /* Get or fake the disk device blocksize.
      35     Usually defined by sys/param.h (if at all).  */
      36  #if !defined DEV_BSIZE && defined BSIZE
      37  # define DEV_BSIZE BSIZE
      38  #endif
      39  #if !defined DEV_BSIZE && defined BBSIZE /* SGI sys/param.h */
      40  # define DEV_BSIZE BBSIZE
      41  #endif
      42  #ifndef DEV_BSIZE
      43  # define DEV_BSIZE 4096
      44  #endif
      45  
      46  
      47  
      48  /* Extract or fake data from a 'struct stat'.
      49     ST_BLKSIZE: Preferred I/O blocksize for the file, in bytes.
      50     ST_NBLOCKS: Number of blocks in the file, including indirect blocks.
      51     ST_NBLOCKSIZE: Size of blocks used when calculating ST_NBLOCKS.  */
      52  #ifndef HAVE_STRUCT_STAT_ST_BLOCKS
      53  # define ST_BLKSIZE(statbuf) DEV_BSIZE
      54    /* coreutils' fileblocks.c also uses BSIZE.  */
      55  # if defined _POSIX_SOURCE || !defined BSIZE
      56  #  define ST_NBLOCKS(statbuf) \
      57    ((statbuf).st_size / ST_NBLOCKSIZE + ((statbuf).st_size % ST_NBLOCKSIZE != 0))
      58  # else
      59     /* This definition calls st_blocks, which is in the fileblocks module. */
      60  #  define ST_NBLOCKS(statbuf) \
      61    (S_ISREG ((statbuf).st_mode) || S_ISDIR ((statbuf).st_mode) ? \
      62     st_blocks ((statbuf).st_size) : 0)
      63  # endif
      64  #else
      65  /* When running 'rsh hpux11-system cat any-file', cat would
      66     determine that the output stream had an st_blksize of 2147421096.
      67     Conversely st_blksize can be 2 GiB (or maybe even larger) with XFS
      68     on 64-bit hosts.  Somewhat arbitrarily, limit the "optimal" block
      69     size to SIZE_MAX / 8 + 1.  (Dividing SIZE_MAX by only 4 wouldn't
      70     suffice, since "cat" sometimes multiplies the result by 4.)  If
      71     anyone knows of a system for which this limit is too small, please
      72     report it as a bug in this code.  */
      73  # define ST_BLKSIZE(statbuf) ((0 < (statbuf).st_blksize \
      74                                 && (statbuf).st_blksize <= ((size_t)-1) / 8 + 1) \
      75                                ? (statbuf).st_blksize : DEV_BSIZE)
      76  # if defined hpux || defined __hpux__ || defined __hpux
      77    /* HP-UX counts st_blocks in 1024-byte units.
      78       This loses when mixing HP-UX and BSD file systems with NFS.  */
      79  #  define ST_NBLOCKSIZE 1024
      80  # endif
      81  #endif
      82  
      83  #ifndef ST_NBLOCKS
      84  # define ST_NBLOCKS(statbuf) ((statbuf).st_blocks)
      85  #endif
      86  
      87  #ifndef ST_NBLOCKSIZE
      88  # ifdef S_BLKSIZE
      89  #  define ST_NBLOCKSIZE S_BLKSIZE
      90  # else
      91  #  define ST_NBLOCKSIZE 512
      92  # endif
      93  #endif
      94  
      95  #endif /* STAT_SIZE_H */