4.4BSD/usr/share/man/cat2/fstat.0
STAT(2) BSD Programmer's Manual STAT(2)
NNAAMMEE
ssttaatt, llssttaatt, ffssttaatt - get file status
SSYYNNOOPPSSIISS
##iinncclluuddee <<ssyyss//ttyyppeess..hh>>
##iinncclluuddee <<ssyyss//ssttaatt..hh>>
_i_n_t
ssttaatt(_c_o_n_s_t _c_h_a_r _*_p_a_t_h, _s_t_r_u_c_t _s_t_a_t _*_b_u_f);
_i_n_t
llssttaatt(_c_o_n_s_t _c_h_a_r _*_p_a_t_h, _s_t_r_u_c_t _s_t_a_t _*_b_u_f);
_i_n_t
ffssttaatt(_i_n_t _f_d, _s_t_r_u_c_t _s_t_a_t _*_b_u_f);
DDEESSCCRRIIPPTTIIOONN
The ssttaatt() function obtains information about the file pointed to by
_p_a_t_h. Read, write or execute permission of the named file is not re-
quired, but all directories listed in the path name leading to the file
must be seachable.
LLssttaatt() is like ssttaatt() except in the case where the named file is a sym-
bolic link, in which case llssttaatt() returns information about the link,
while ssttaatt() returns information about the file the link references. Un-
like other filesystem objects, symbolic links do not have an owner,
group, access mode, times, etc. Instead, these attributes are taken from
the directory that contains the link. The only attributes returned from
an llssttaatt() that refer to the symbolic link itself are the file type
(S_IFLNK), size, blocks, and link count (always 1).
The ffssttaatt() obtains the same information about an open file known by the
file descriptor _f_d, such as would be obtained by an open call.
_B_u_f is a pointer to a ssttaatt() structure as defined by <_s_y_s_/_s_t_a_t_._h> (shown
below) and into which information is placed concerning the file.
struct stat {
dev_t st_dev; /* device inode resides on */
ino_t st_ino; /* inode's number */
mode_t st_mode; /* inode protection mode */
nlink_t st_nlink; /* number or hard links to the file */
uid_t st_uid; /* user-id of owner */
gid_t st_gid; /* group-id of owner */
dev_t st_rdev; /* device type, for special file inode */
off_t st_size; /* file size, in bytes */
time_t st_atime; /* time of last access */
long st_spare1;
time_t st_mtime; /* time of last data modification */
long st_spare2;
time_t st_ctime; /* time of last file status change */
long st_spare3;
long st_blksize;/* optimal file sys I/O ops blocksize */
long st_blocks; /* blocks allocated for file */
u_long st_flags; /* user defined flags for file */
u_long st_gen; /* file generation number */
};
The time-related fields of _s_t_r_u_c_t _s_t_a_t are as follows:
st_atime Time when file data last accessed. Changed by the following
system calls: mknod(2), utimes(2), and read(2).
st_mtime Time when file data last modified. Changed by the following
system calls: mknod(2), utimes(2), write(2).
st_ctime Time when file status was last changed (inode data modifica-
tion). Changed by the following system calls: chmod(2)
chown(2), link(2), mknod(2), rename(2), unlink(2),
utimes(2), write(2).
st_blocks The actual number of blocks allocated for the file in 512-byte
units.
The status information word _s_t___m_o_d_e has bits:
#define S_IFMT 0170000 /* type of file */
#define S_IFIFO 0010000 /* named pipe (fifo) */
#define S_IFCHR 0020000 /* character special */
#define S_IFDIR 0040000 /* directory */
#define S_IFBLK 0060000 /* block special */
#define S_IFREG 0100000 /* regular */
#define S_IFLNK 0120000 /* symbolic link */
#define S_IFSOCK 0140000 /* socket */
#define S_ISUID 0004000 /* set user id on execution */
#define S_ISGID 0002000 /* set group id on execution */
#define S_ISVTX 0001000 /* save swapped text even after use */
#define S_IRUSR 0000400 /* read permission, owner */
#define S_IWUSR 0000200 /* write permission, owner */
#define S_IXUSR 0000100 /* execute/search permission, owner */
For a list of access modes, see <_s_y_s_/_s_t_a_t_._h>, access(2) and chmod(2).
RREETTUURRNN VVAALLUUEESS
Upon successful completion a value of 0 is returned. Otherwise, a value
of -1 is returned and _e_r_r_n_o is set to indicate the error.
EERRRROORRSS
SSttaatt() and llssttaatt() will fail if:
[ENOTDIR] A component of the path prefix is not a directory.
[EINVAL] The pathname contains a character with the high-order bit
set.
[ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an
entire path name exceeded 1023 characters.
[ENOENT] The named file does not exist.
[EACCES] Search permission is denied for a component of the path
prefix.
[ELOOP] Too many symbolic links were encountered in translating
the pathname.
[EFAULT] _B_u_f or _n_a_m_e points to an invalid address.
[EIO] An I/O error occurred while reading from or writing to
the file system.
FFssttaatt() will fail if:
[EBADF] _f_d is not a valid open file descriptor.
[EFAULT] _B_u_f points to an invalid address.
[EIO] An I/O error occurred while reading from or writing to the file
system.
CCAAVVEEAATT
The fields in the stat structure currently marked _s_t___s_p_a_r_e_1, _s_t___s_p_a_r_e_2,
and _s_t___s_p_a_r_e_3 are present in preparation for inode time stamps expanding
to 64 bits. This, however, can break certain programs that depend on the
time stamps being contiguous (in calls to utimes(2)).
SSEEEE AALLSSOO
chmod(2), chown(2), utimes(2) symlink(7)
BBUUGGSS
Applying fstat to a socket (and thus to a pipe) returns a zero'd buffer,
except for the blocksize field, and a unique device and inode number.
SSTTAANNDDAARRDDSS
The ssttaatt() and ffssttaatt() function calls are expected to conform to IEEE Std
1003.1-1988 (``POSIX'').
HHIISSTTOORRYY
A llssttaatt function call appeared in 4.2BSD.
4th Berkeley Distribution June 4, 1993 3