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Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)stat.2 8.4 (Berkeley) 5/1/95 29.\" $FreeBSD$ 30.\" 31.Dd September 23, 2020 32.Dt STAT 2 33.Os 34.Sh NAME 35.Nm stat , 36.Nm lstat , 37.Nm fstat , 38.Nm fstatat 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 * restrict path" "struct stat * restrict sb" 46.Ft int 47.Fn lstat "const char * restrict path" "struct stat * restrict sb" 48.Ft int 49.Fn fstat "int fd" "struct stat *sb" 50.Ft int 51.Fn fstatat "int fd" "const char *path" "struct stat *sb" "int flag" 52.Sh DESCRIPTION 53The 54.Fn stat 55system call obtains information about the file pointed to by 56.Fa path . 57Read, write or execute 58permission of the named file is not required, but all directories 59listed in the path name leading to the file must be searchable. 60.Pp 61The 62.Fn lstat 63system call is like 64.Fn stat 65except when the named file is a symbolic link, 66in which case 67.Fn lstat 68returns information about the link, 69while 70.Fn stat 71returns information about the file the link references. 72.Pp 73The 74.Fn fstat 75system call obtains the same information about an open file 76known by the file descriptor 77.Fa fd . 78.Pp 79The 80.Fn fstatat 81system call is equivalent to 82.Fn stat 83and 84.Fn lstat 85except when the 86.Fa path 87specifies a relative path, or the 88.Dv AT_BENEATH 89flag is provided. 90For 91.Fn fstatat 92and relative 93.Fa path , 94the status is retrieved from a file relative to 95the directory associated with the file descriptor 96.Fa fd 97instead of the current working directory. 98For 99.Dv AT_BENEATH 100and absolute 101.Fa path , 102the status is retrieved from a file specified by the 103.Fa path , 104but additional permission checks are performed, see below. 105.Pp 106The values for the 107.Fa flag 108are constructed by a bitwise-inclusive OR of flags from this list, 109defined in 110.In fcntl.h : 111.Bl -tag -width indent 112.It Dv AT_SYMLINK_NOFOLLOW 113If 114.Fa path 115names a symbolic link, the status of the symbolic link is returned. 116.It Dv AT_BENEATH 117Only stat files and directories below the topping directory. 118See the description of the 119.Dv O_BENEATH 120flag in the 121.Xr open 2 122manual page. 123.It Dv AT_RESOLVE_BENEATH 124Only walks paths below the topping directory. 125See the description of the 126.Dv O_RESOLVE_BENEATH 127flag in the 128.Xr open 2 129manual page. 130.El 131.Pp 132If 133.Fn fstatat 134is passed the special value 135.Dv AT_FDCWD 136in the 137.Fa fd 138parameter, the current working directory is used and the behavior is 139identical to a call to 140.Fn stat 141or 142.Fn lstat 143respectively, depending on whether or not the 144.Dv AT_SYMLINK_NOFOLLOW 145bit is set in 146.Fa flag . 147.Pp 148When 149.Fn fstatat 150is called with an absolute 151.Fa path 152without the 153.Dv AT_BENEATH 154flag, it ignores the 155.Fa fd 156argument. 157When 158.Dv AT_BENEATH 159is specified with an absolute 160.Fa path , 161a directory passed by the 162.Fa fd 163argument is used as the topping point for the resolution. 164.Pp 165The 166.Fa sb 167argument is a pointer to a 168.Vt stat 169structure 170as defined by 171.In sys/stat.h 172and into which information is placed concerning the file. 173.Pp 174The fields of 175.Vt "struct stat" 176related to the file system are: 177.Bl -tag -width ".Va st_nlink" 178.It Va st_dev 179Numeric ID of the device containing the file. 180.It Va st_ino 181The file's inode number. 182.It Va st_nlink 183Number of hard links to the file. 184.It Va st_flags 185Flags enabled for the file. 186See 187.Xr chflags 2 188for the list of flags and their description. 189.El 190.Pp 191The 192.Va st_dev 193and 194.Va st_ino 195fields together identify the file uniquely within the system. 196.Pp 197The time-related fields of 198.Vt "struct stat" 199are: 200.Bl -tag -width ".Va st_birthtim" 201.It Va st_atim 202Time when file data was last accessed. 203Changed implicitly by syscalls such as 204.Xr read 2 205and 206.Xr readv 2 , 207and explicitly by 208.Xr utimes 2 . 209.It Va st_mtim 210Time when file data was last modified. 211Changed implicitly by syscalls such as 212.Xr truncate 2 , 213.Xr write 2 , 214and 215.Xr writev 2 , 216and explicitly by 217.Xr utimes 2 . 218Also, any syscall which modifies directory content changes the 219.Va st_mtim 220for the affected directory. 221For instance, 222.Xr creat 2 , 223.Xr mkdir 2 , 224.Xr rename 2 , 225.Xr link 2 , 226and 227.Xr unlink 2 . 228.It Va st_ctim 229Time when file status was last changed (inode data modification). 230Changed implicitly by any syscall that affects file metadata, including 231.Va st_mtim , 232such as 233.Xr chflags 2 , 234.Xr chmod 2 , 235.Xr chown 2 , 236.Xr truncate 2 , 237.Xr utimes 2 , 238and 239.Xr write 2 . 240Also, any syscall which modifies directory content changes the 241.Va st_ctim 242for the affected directory. 243For instance, 244.Xr creat 2 , 245.Xr mkdir 2 , 246.Xr rename 2 , 247.Xr link 2 , 248and 249.Xr unlink 2 . 250.It Va st_birthtim 251Time when the inode was created. 252.El 253.Pp 254These time-related macros are defined for compatibility: 255.Bd -literal 256#define st_atime st_atim.tv_sec 257#define st_mtime st_mtim.tv_sec 258#define st_ctime st_ctim.tv_sec 259#ifndef _POSIX_SOURCE 260#define st_birthtime st_birthtim.tv_sec 261#endif 262 263#ifndef _POSIX_SOURCE 264#define st_atimespec st_atim 265#define st_mtimespec st_mtim 266#define st_ctimespec st_ctim 267#define st_birthtimespec st_birthtim 268#endif 269.Ed 270.Pp 271Size-related fields of the 272.Vt "struct stat" 273are: 274.Bl -tag -width ".Va st_blksize" 275.It Va st_size 276File size in bytes. 277.It Va st_blksize 278Optimal I/O block size for the file. 279.It Va st_blocks 280Actual number of blocks allocated for the file in 512-byte units. 281As short symbolic links are stored in the inode, this number may 282be zero. 283.El 284.Pp 285The access-related fields of 286.Vt "struct stat" 287are: 288.Bl -tag -width ".Va st_mode" 289.It Va st_uid 290User ID of the file's owner. 291.It Va st_gid 292Group ID of the file. 293.It Va st_mode 294Status of the file (see below). 295.El 296.Pp 297The status information word 298.Fa st_mode 299has these bits: 300.Bd -literal 301#define S_IFMT 0170000 /* type of file mask */ 302#define S_IFIFO 0010000 /* named pipe (fifo) */ 303#define S_IFCHR 0020000 /* character special */ 304#define S_IFDIR 0040000 /* directory */ 305#define S_IFBLK 0060000 /* block special */ 306#define S_IFREG 0100000 /* regular */ 307#define S_IFLNK 0120000 /* symbolic link */ 308#define S_IFSOCK 0140000 /* socket */ 309#define S_IFWHT 0160000 /* whiteout */ 310#define S_ISUID 0004000 /* set user id on execution */ 311#define S_ISGID 0002000 /* set group id on execution */ 312#define S_ISVTX 0001000 /* save swapped text even after use */ 313#define S_IRWXU 0000700 /* RWX mask for owner */ 314#define S_IRUSR 0000400 /* read permission, owner */ 315#define S_IWUSR 0000200 /* write permission, owner */ 316#define S_IXUSR 0000100 /* execute/search permission, owner */ 317#define S_IRWXG 0000070 /* RWX mask for group */ 318#define S_IRGRP 0000040 /* read permission, group */ 319#define S_IWGRP 0000020 /* write permission, group */ 320#define S_IXGRP 0000010 /* execute/search permission, group */ 321#define S_IRWXO 0000007 /* RWX mask for other */ 322#define S_IROTH 0000004 /* read permission, other */ 323#define S_IWOTH 0000002 /* write permission, other */ 324#define S_IXOTH 0000001 /* execute/search permission, other */ 325.Ed 326.Pp 327For a list of access modes, see 328.In sys/stat.h , 329.Xr access 2 330and 331.Xr chmod 2 . 332These macros are available to test whether a 333.Va st_mode 334value passed in the 335.Fa m 336argument corresponds to a file of the specified type: 337.Bl -tag -width ".Fn S_ISFIFO m" 338.It Fn S_ISBLK m 339Test for a block special file. 340.It Fn S_ISCHR m 341Test for a character special file. 342.It Fn S_ISDIR m 343Test for a directory. 344.It Fn S_ISFIFO m 345Test for a pipe or FIFO special file. 346.It Fn S_ISLNK m 347Test for a symbolic link. 348.It Fn S_ISREG m 349Test for a regular file. 350.It Fn S_ISSOCK m 351Test for a socket. 352.It Fn S_ISWHT m 353Test for a whiteout. 354.El 355.Pp 356The macros evaluate to a non-zero value if the test is true 357or to the value 0 if the test is false. 358.Sh RETURN VALUES 359.Rv -std 360.Sh COMPATIBILITY 361Previous versions of the system used different types for the 362.Va st_dev , 363.Va st_uid , 364.Va st_gid , 365.Va st_rdev , 366.Va st_size , 367.Va st_blksize 368and 369.Va st_blocks 370fields. 371.Sh ERRORS 372The 373.Fn stat 374and 375.Fn lstat 376system calls will fail if: 377.Bl -tag -width Er 378.It Bq Er EACCES 379Search permission is denied for a component of the path prefix. 380.It Bq Er EFAULT 381The 382.Fa sb 383or 384.Fa path 385argument 386points to an invalid address. 387.It Bq Er EIO 388An I/O error occurred while reading from or writing to the file system. 389.It Bq Er EINTEGRITY 390Corrupted data was detected while reading from the file system. 391.It Bq Er ELOOP 392Too many symbolic links were encountered in translating the pathname. 393.It Bq Er ENAMETOOLONG 394A component of a pathname exceeded 255 characters, 395or an entire path name exceeded 1023 characters. 396.It Bq Er ENOENT 397The named file does not exist. 398.It Bq Er ENOTDIR 399A component of the path prefix is not a directory. 400.It Bq Er EOVERFLOW 401The file size in bytes cannot be 402represented correctly in the structure pointed to by 403.Fa sb . 404.El 405.Pp 406The 407.Fn fstat 408system call will fail if: 409.Bl -tag -width Er 410.It Bq Er EBADF 411The 412.Fa fd 413argument 414is not a valid open file descriptor. 415.It Bq Er EFAULT 416The 417.Fa sb 418argument 419points to an invalid address. 420.It Bq Er EIO 421An I/O error occurred while reading from or writing to the file system. 422.It Bq Er EINTEGRITY 423Corrupted data was detected while reading from the file system. 424.It Bq Er EOVERFLOW 425The file size in bytes cannot be 426represented correctly in the structure pointed to by 427.Fa sb . 428.El 429.Pp 430In addition to the errors returned by the 431.Fn lstat , 432the 433.Fn fstatat 434may fail if: 435.Bl -tag -width Er 436.It Bq Er EBADF 437The 438.Fa path 439argument does not specify an absolute path and the 440.Fa fd 441argument is neither 442.Dv AT_FDCWD 443nor a valid file descriptor open for searching. 444.It Bq Er EINVAL 445The value of the 446.Fa flag 447argument is not valid. 448.It Bq Er ENOTDIR 449The 450.Fa path 451argument is not an absolute path and 452.Fa fd 453is neither 454.Dv AT_FDCWD 455nor a file descriptor associated with a directory. 456.It Bq Er ENOTCAPABLE 457.Fa path 458is an absolute path, 459or contained a ".." component leading to a 460directory outside of the directory hierarchy specified by 461.Fa fd , 462and the process is in capability mode. 463.It Bq Er ENOTCAPABLE 464The 465.Dv AT_BENEATH 466flag was provided to 467.Fn fstatat , 468and the absolute 469.Fa path 470does not have its tail fully contained under the topping directory, 471or the relative 472.Fa path 473escapes it. 474.El 475.Sh SEE ALSO 476.Xr access 2 , 477.Xr chmod 2 , 478.Xr chown 2 , 479.Xr fhstat 2 , 480.Xr statfs 2 , 481.Xr utimes 2 , 482.Xr sticky 7 , 483.Xr symlink 7 484.Sh STANDARDS 485The 486.Fn stat 487and 488.Fn fstat 489system calls are expected to conform to 490.St -p1003.1-90 . 491The 492.Fn fstatat 493system call follows The Open Group Extended API Set 2 specification. 494.Sh HISTORY 495The 496.Fn stat 497and 498.Fn fstat 499system calls appeared in 500.At v1 . 501The 502.Fn lstat 503system call appeared in 504.Bx 4.2 . 505The 506.Fn fstatat 507system call appeared in 508.Fx 8.0 . 509.Sh BUGS 510Applying 511.Fn fstat 512to a socket 513returns a zeroed buffer, 514except for the blocksize field, 515and a unique device and inode number. 516