stat(2)

NAME

stat, lstat, fstat − get file status

SYNOPSIS

#include <sys/types.h>
#include <sys/stat.h>

int stat(const char ∗path, struct stat ∗buf);

int lstat(const char ∗path, struct stat ∗buf);

int fstat(int fildes, struct stat ∗buf);

MT-LEVEL

stat() and fstat() are Async-Signal-Safe

DESCRIPTION

stat() obtains information about the file pointed to by path. Read, write, or execute permission of the named file is not required, but all directories listed in the path name leading to the file must be searchable.

lstat() obtains file attributes similar to stat(), except when the named file is a symbolic link; in that case lstat() returns information about the link, while stat() returns information about the file the link references.

fstat() obtains information about an open file known by the file descriptor fildes, obtained from a successful open, creat, dup, fcntl, or pipe function.

buf is a pointer to a stat() structure into which information is placed concerning the file.

The contents of the structure pointed to by buf include the following members:

mode_tst_mode;/∗ File mode (see mknod(2)) ∗/
ino_tst_ino;/∗ Inode number ∗/
dev_tst_dev;/∗ ID of device containing ∗/
/∗ a directory entry for this file ∗/
dev_tst_rdev;/∗ ID of device ∗/
/∗ This entry is defined only for ∗/
/∗ char special or block special files ∗/
nlink_tst_nlink;/∗ Number of links ∗/
uid_tst_uid;/∗ User ID of the file’s owner ∗/
gid_tst_gid;/∗ Group ID of the file’s group ∗/
off_tst_size;/∗ File size in bytes ∗/
time_tst_atime;/∗ Time of last access ∗/
time_tst_mtime;/∗ Time of last data modification ∗/
time_tst_ctime;/∗ Time of last file status change ∗/
/∗ Times measured in seconds since ∗/
/∗ 00:00:00 UTC, Jan. 1, 1970 ∗/
longst_blksize;/∗ Preferred I/O block size ∗/
longst_blocks;/∗ Number of 512 byte blocks allocated∗/

st_mode The mode of the file as described in mknod(2). In addition to the modes described in mknod(2), the mode of a file may also be S_IFLNK if the file is a symbolic link. (Note that S_IFLNK may only be returned by lstat().)

st_ino This field uniquely identifies the file in a given file system. The pair st_ino and st_dev uniquely identifies regular files.

st_dev This field uniquely identifies the file system that contains the file. Its value may be used as input to the ustat() function to determine more information about this file system. No other meaning is associated with this value.

st_rdev This field should be used only by administrative commands. It is valid only for block special or character special files and only has meaning on the system where the file was configured.

st_nlink This field should be used only by administrative commands.

st_uid The user ID of the file’s owner.

st_gid The group ID of the file’s group.

st_size For regular files, this is the address of the end of the file. For block special or character special, this is not defined. See also pipe(2).

st_atime Time when file data was last accessed. Changed by the following functions: creat, mknod, pipe, utime, and read.

st_mtime
Time when data was last modified. Changed by the following functions: creat, mknod, pipe, utime, and write.

st_ctime Time when file status was last changed. Changed by the following functions: chmod, chown, creat, link, mknod, pipe, unlink, utime, and write.

st_blksize
A hint as to the "best" unit size for I/O operations. This field is not defined for block special or character special files.

st_blocks The total number of physical blocks of size 512 bytes actually allocated on disk. This field is not defined for block special or character special files.

RETURN VALUES

Upon successful completion a value of 0 is returned. Otherwise, a value of −1 is returned and errno is set to indicate the error.

ERRORS

stat() and lstat() fail if one or more of the following are true:

EACCES Search permission is denied for a component of the path prefix.

EFAULT buf or path points to an illegal address.

EINTR A signal was caught during the stat() or lstat() function.

ELOOP Too many symbolic links were encountered in translating path.

EMULTIHOP Components of path require hopping to multiple remote machines and the file system does not allow it.

ENAMETOOLONG The length of the path argument exceeds {PATH_MAX}, or the length of a path component exceeds {NAME_MAX} while {_POSIX_NO_TRUNC} is in effect.

ENOENT The named file does not exist or is the null pathname.

ENOLINK path points to a remote machine and the link to that machine is no longer active.

ENOTDIR A component of the path prefix is not a directory.

EOVERFLOW A component is too large to store in the structure pointed to by buf.

fstat() fails if one or more of the following are true:

EBADF fildes is not a valid open file descriptor.

EFAULT buf points to an illegal address.

EINTR A signal was caught during the fstat() function.

ENOLINK fildes points to a remote machine and the link to that machine is no longer active.