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) (Minix-vmd)
int fstat(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. (Minix-vmd) (Under minix, lstat
behaves like stat.)
Fstat obtains the same information about an open file refer-
enced by the argument descriptor, such as would be obtained
by an open call. Pipe descriptors look like named pipes
with a link count of zero. The st_size field of pipes or
named pipes shows the amount of bytes currently buffered in
the pipe.
Buf is a pointer to a stat structure into which information
is placed concerning the file. The contents of the struc-
ture pointed to by buf is as follows:
struct stat {
dev_t st_dev; /* device inode resides on */
ino_t st_ino; /* this inode's number */
mode_t st_mode; /* file mode, protection bits, etc. */
nlink_t st_nlink; /* number or hard links to the file */
uid_t st_uid; /* user-id of the file's owner */
gid_t st_gid; /* group-id of the file's owner */
dev_t st_rdev; /* the device type, for inode that is device */
off_t st_size; /* total size of file */
time_t st_atime; /* time of last access */
time_t st_mtime; /* time of last data modification */
time_t st_ctime; /* time of last file status change */
};
st_atime Time when file data was last read or modified.
Changed by the following system calls:
mknod(2), utime(2), read(2), and write(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), utime(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), utime(2), write(2).
The file type information in st_mode has bits:
#define S_IFMT 0170000 /* type of file */
#define S_IFIFO 0010000/* named pipe */
#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 (Minix-vmd) */
The mode bits 0007777 encode set-uid/gid bits and permission
bits (see chmod(2)).
RETURN VALUE
Upon successful completion a value of 0 is returned. Other-
wise, a value of -1 is returned and errno is set to indicate
the error.
ERRORS
Stat and lstat will fail if one or more of the following are
true:
[ENOTDIR] A component of the path prefix is not a
directory.
[ENAMETOOLONG] The path name exceeds PATH_MAX 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. (Minix-vmd)
[EFAULT] Buf or name points to an invalid address.
[EIO] An I/O error occurred while reading from or
writing to the file system.
Fstat will fail if one or both of the following are true:
[EBADF] Fildes is not a valid open file descriptor.
[EFAULT] Buf points to an invalid address.
[EIO] An I/O error occurred while reading from or
writing to the file system.
SEE ALSO
chmod(2), chown(2), utime(2).