1.\" $NetBSD: stat.2,v 1.33 2004/05/13 10:20:58 wiz Exp $ 2.\" 3.\" Copyright (c) 1980, 1991, 1993, 1994 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)stat.2 8.4 (Berkeley) 5/1/95 31.\" 32.Dd May 1, 1995 33.Dt STAT 2 34.Os 35.Sh NAME 36.Nm stat , 37.Nm lstat , 38.Nm fstat 39.Nd get file status 40.Sh LIBRARY 41.Lb libc 42.Sh SYNOPSIS 43.In sys/stat.h 44.Ft int 45.Fn stat "const char *path" "struct stat *sb" 46.Ft int 47.Fn lstat "const char *path" "struct stat *sb" 48.Ft int 49.Fn fstat "int fd" "struct stat *sb" 50.Sh DESCRIPTION 51The 52.Fn stat 53function obtains information about the file pointed to by 54.Fa path . 55Read, write or execute 56permission of the named file is not required, but all directories 57listed in the path name leading to the file must be searchable. 58.Pp 59.Fn lstat 60is like 61.Fn stat 62except in the case where the named file is a symbolic link, 63in which case 64.Fn lstat 65returns information about the link, 66while 67.Fn stat 68returns information about the file the link references. 69.Pp 70The 71.Fn fstat 72function obtains the same information about an open file 73known by the file descriptor 74.Fa fd . 75.Pp 76The 77.Fa sb 78argument is a pointer to a 79.Fa stat 80structure 81as defined by 82.Aq Pa sys/stat.h 83(shown below) 84and into which information is placed concerning the file. 85.Bd -literal 86struct stat { 87 dev_t st_dev; /* device containing the file */ 88 ino_t st_ino; /* file's serial number */ 89 mode_t st_mode; /* file's mode (protection and type) */ 90 nlink_t st_nlink; /* number of hard links to the file */ 91 uid_t st_uid; /* user-id of owner */ 92 gid_t st_gid; /* group-id of owner */ 93 dev_t st_rdev; /* device type, for device special file */ 94 struct timespec st_atimespec; /* time of last access */ 95 struct timespec st_mtimespec; /* time of last data modification */ 96 struct timespec st_ctimespec; /* time of last file status change */ 97 off_t st_size; /* file size, in bytes */ 98 int64_t st_blocks; /* blocks allocated for file */ 99 u_int32_t st_blksize; /* optimal file sys I/O ops blocksize */ 100 u_int32_t st_flags; /* user defined flags for file */ 101 u_int32_t st_gen; /* file generation number */ 102}; 103.Ed 104.Pp 105The time-related fields of 106.Fa struct stat 107are as follows: 108.Bl -tag -width XXXst_mtime 109.It st_atime 110Time when file data was last accessed. 111Changed by the 112.Xr mknod 2 , 113.Xr utimes 2 114and 115.Xr read 2 116system calls. 117.It st_mtime 118Time when file data was last modified. 119Changed by the 120.Xr mknod 2 , 121.Xr utimes 2 122and 123.Xr write 2 124system calls. 125.It st_ctime 126Time when file status was last changed (file metadata modification). 127Changed by the 128.Xr chflags 2 , 129.Xr chmod 2 , 130.Xr chown 2 , 131.Xr link 2 , 132.Xr mknod 2 , 133.Xr rename 2 , 134.Xr unlink 2 , 135.Xr utimes 2 136and 137.Xr write 2 138system calls. 139.El 140.Pp 141The size-related fields of the 142.Fa struct stat 143are as follows: 144.Bl -tag -width XXXst_blksize 145.It st_size 146The size of the file in bytes. 147A directory will be a multiple of the size of the 148.Xr dirent 5 149structure. 150.It st_blksize 151The optimal I/O block size for the file. 152.It st_blocks 153The actual number of blocks allocated for the file in 512-byte units. 154As short symbolic links are stored in the inode, this number may 155be zero. 156.El 157.Pp 158The status information word 159.Fa st_mode 160has the following bits: 161.Bd -literal 162#define S_IFMT 0170000 /* type of file */ 163#define S_IFIFO 0010000 /* named pipe (fifo) */ 164#define S_IFCHR 0020000 /* character special */ 165#define S_IFDIR 0040000 /* directory */ 166#define S_IFBLK 0060000 /* block special */ 167#define S_IFREG 0100000 /* regular */ 168#define S_IFLNK 0120000 /* symbolic link */ 169#define S_IFSOCK 0140000 /* socket */ 170#define S_IFWHT 0160000 /* whiteout */ 171#define S_ISUID 0004000 /* set user id on execution */ 172#define S_ISGID 0002000 /* set group id on execution */ 173#define S_ISVTX 0001000 /* save swapped text even after use */ 174#define S_IRUSR 0000400 /* read permission, owner */ 175#define S_IWUSR 0000200 /* write permission, owner */ 176#define S_IXUSR 0000100 /* execute/search permission, owner */ 177#define S_IRGRP 0000040 /* read permission, group */ 178#define S_IWGRP 0000020 /* write permission, group */ 179#define S_IXGRP 0000010 /* execute/search permission, group */ 180#define S_IROTH 0000004 /* read permission, other */ 181#define S_IWOTH 0000002 /* write permission, other */ 182#define S_IXOTH 0000001 /* execute/search permission, other */ 183.Ed 184.Pp 185For a list of access modes, see 186.Aq Pa sys/stat.h , 187.Xr access 2 188and 189.Xr chmod 2 . 190.Pp 191The status information word 192.Fa st_flags 193has the following bits: 194.Bd -literal 195#define UF_NODUMP 0x00000001 /* do not dump file */ 196#define UF_IMMUTABLE 0x00000002 /* file may not be changed */ 197#define UF_APPEND 0x00000004 /* writes to file may only append */ 198#define UF_OPAQUE 0x00000008 /* directory is opaque wrt. union */ 199#define SF_ARCHIVED 0x00010000 /* file is archived */ 200#define SF_IMMUTABLE 0x00020000 /* file may not be changed */ 201#define SF_APPEND 0x00040000 /* writes to file may only append */ 202.Ed 203.Pp 204For a description of the flags, see 205.Xr chflags 2 . 206.Sh RETURN VALUES 207Upon successful completion a value of 0 is returned. 208Otherwise, a value of \-1 is returned and 209.Va errno 210is set to indicate the error. 211.Sh COMPATIBILITY 212Previous versions of the system used different types for the 213.Li st_dev , 214.Li st_uid , 215.Li st_gid , 216.Li st_rdev , 217.Li st_size , 218.Li st_blksize 219and 220.Li st_blocks 221fields. 222.Sh ERRORS 223.Fn stat 224and 225.Fn lstat 226will fail if: 227.Bl -tag -width Er 228.It Bq Er ENOTDIR 229A component of the path prefix is not a directory. 230.It Bq Er ENAMETOOLONG 231A component of a pathname exceeded 232.Dv {NAME_MAX} 233characters, or an entire path name exceeded 234.Dv {PATH_MAX} 235characters. 236.It Bq Er ENOENT 237The named file does not exist. 238.It Bq Er EACCES 239Search permission is denied for a component of the path prefix. 240.It Bq Er ELOOP 241Too many symbolic links were encountered in translating the pathname. 242.It Bq Er EFAULT 243.Fa sb 244or 245.Em name 246points to an invalid address. 247.It Bq Er ENXIO 248The named file is a character special or block 249special file, and the device associated with this special file 250does not exist. 251.It Bq Er EIO 252An I/O error occurred while reading from or writing to the file system. 253.It Bq Er EBADF 254A badly formed v-node was encountered. 255This can happen if a file system information node is incorrect. 256.El 257.Pp 258.Bl -tag -width Er 259.Fn fstat 260will fail if: 261.It Bq Er EBADF 262.Fa fd 263is not a valid open file descriptor. 264.It Bq Er EFAULT 265.Fa sb 266points to an invalid address. 267.It Bq Er EIO 268An I/O error occurred while reading from or writing to the file system. 269.El 270.Sh SEE ALSO 271.Xr chflags 2 , 272.Xr chmod 2 , 273.Xr chown 2 , 274.Xr utimes 2 , 275.Xr dir 5 , 276.Xr symlink 7 277.Sh STANDARDS 278The 279.Fn stat 280and 281.Fn fstat 282functions conform to 283.St -p1003.1-90 . 284.Sh HISTORY 285A 286.Fn lstat 287function call appeared in 288.Bx 4.2 . 289.Sh BUGS 290Applying 291.Fn fstat 292to a socket (and thus to a pipe) 293returns a zero'd buffer, 294except for the blocksize field, 295and a unique device and file serial number. 296