1 /* macros useful in interpreting size-related values in struct stat. 2 Copyright (C) 1989, 1991-2021 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 */