STAT(2) COMMAND REFERENCE STAT(2)
NAME
stat, lstat, fstat - get file status
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
stat(path, buf)
char *path;
struct stat *buf;
lstat(path, buf)
char *path;
struct stat *buf;
fstat(fd, buf)
int fd;
struct stat *buf;
DESCRIPTION
Stat obtains information about the file 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 reachable.
Lstat is like stat except in the case where the named file
is a symbolic link, in which case lstat returns information
about the link, while stat returns information about the
file the link references.
Fstat obtains the same information about an open file
referenced by fd, such as would be obtained by an open call.
Buf is a pointer to a stat structure into which information
is placed concerning the file. The structure is defined in
<sys/stat.h> as:
struct stat {
dev_t st_dev; /* ID of device containing a directory entry */
/* for this file */
ino_t st_ino; /* this inode's number */
u_short st_mode; /* file mode; see below */
short st_nlink; /* number of hard links to the file */
short st_uid; /* user ID of the file's owner */
short st_gid; /* group ID of the file's group */
dev_t st_rdev; /* ID of device -- this entry is defined only */
/* for character special or block special files */
off_t st_size; /* total size of file */
time_t st_atime; /* time of last access */
int st_spare1;
time_t st_mtime; /* time of last data modification */
int st_spare2;
Printed 10/17/86 1
STAT(2) COMMAND REFERENCE STAT(2)
time_t st_ctime; /* time of last file status change */
int st_spare3;
long st_blksize; /* optimal blocksize for file system I/O ops */
long st_blocks; /* actual number of blocks allocated */
long st_hostid; /* hostid of machine where file is located */
long st_spare4;
};
st_atime Time when file data was last read or modified.
Changed by the following system calls:
mknod(2), utimes(2), and read(2). For reasons
of efficiency, st_atime is not set when a
directory is searched, although this would be
more logical.
st_mtime Time when data was last modified. It is not set
by changes of owner, group, link count, or mode.
Changed by the following system calls:
mknod(2), utimes(2), write(2).
st_ctime Time when file status was last changed. It is
set both both by writing and changing the i-
node. Changed by the following system calls:
chmod(2) chown(2), link(2), mknod(2), rename(2),
unlink(2), utimes(2), write(2).
The status information word st_mode has these bits:
#define S_IFMT 0170000 /* type of file */
#define S_IFDIR 0040000 /* directory */
#define S_IFCHR 0020000 /* character special */
#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_IREAD 0000400 /* read permission, owner */
#define S_IWRITE 0000200 /* write permission, owner */
#define S_IEXEC 0000100 /* execute/search permission, owner */
The mode bits 0000070 and 0000007 encode group and others
permissions (see chmod(2)).
When fd is associated with a pipe, fstat reports an ordinary
file with an i-node number, restricted permissions, and a
not necessarily meaningful length.
DIAGNOSTICS
Stat and lstat will fail if one or more of the following are
true:
Printed 10/17/86 2
STAT(2) COMMAND REFERENCE STAT(2)
[ENOTDIR]
A component of the path prefix is not a directory.
[ENOASCII]
The pathname contains a character with the high-order
bit set.
[ENAMETOOLONG]
The pathname is too long.
[ENOENT]
The named file does not exist.
[EACCES]
Search permission is denied for a component of the path
prefix. If the file is located on a remote host, this
error code will be returned if the local host name and
local user name does not appear in /usr/lib/dfs/access
on the remote machine. See access(dfs)(5n).
[EFAULT]
Buf or path points to an invalid address.
[ELOOP]
Too many symbolic links were encountered in translating
the pathname.
[EIO]
An I/O error occurred while reading from or writing to
the file system.
Fstat will fail if one of the following are true:
[EBADF]
Fd is not a valid open file descriptor.
[EDFSNOSUCHHOST]
The pathname referenced a remote host, but when we
broadcast a request for its address, no host responded.
[EIO]
An I/O error occurred while reading from or writing to
the file system.
RETURN VALUE
Upon successful completion a value of 0 is returned.
Otherwise, a value of -1 is returned and errno is set to
indicate the error.
CAVEATS
The fields in the stat structure currently marked st_spare1,
st_spare2, and st_spare3 are present in preparation for
Printed 10/17/86 3
STAT(2) COMMAND REFERENCE STAT(2)
inode time stamps expanding to 64 bits. This, however, can
break certain programs which depend on the time stamps being
contiguous (in calls to utimes(2)).
Applying fstat to a socket returns a zeroed buffer.
SEE ALSO
chmod(2), chown(2), utimes(2).
Printed 10/17/86 4
%%index%%
na:72,72;
sy:144,1219;
de:1363,1929;3436,2614;
di:6050,209;6403,1340;
rv:7743,235;
ca:7978,225;8347,273;
se:8620,169;
%%index%%000000000151