NetBSD/lib/libc/sys/statfs.2

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.\"	from: @(#)statfs.2	8.3 (Berkeley) 2/11/94
.\"	$Id: statfs.2,v 1.8 1994/08/26 12:55:25 mycroft Exp $
.\"
.Dd February 11, 1994
.Dt STATFS 2
.Os
.Sh NAME
.Nm statfs
.Nd get file system statistics
.Sh SYNOPSIS
.Fd #include <sys/param.h>
.Fd #include <sys/mount.h>
.Ft int
.Fn statfs "const char *path" "struct statfs *buf"
.Ft int
.Fn fstatfs "int fd" "struct statfs *buf"
.Sh DESCRIPTION
.Fn Statfs
returns information about a mounted file system.
.Fa Path
is the path name of any file within the mounted filesystem.
.Fa Buf
is a pointer to a
.Fn statfs
structure defined as follows:
.Bd -literal
typedef struct { long val[2]; } fsid_t;

#define	MFSNAMELEN	15	/* length of fs type name, not inc. null */
#define	MNAMELEN	90	/* length of buffer for returned name */

struct statfs {
	short	f_type;		  /* type of filesystem (unused; zero) */
	short	f_flags;	  /* copy of mount flags */
	long	f_bsize;	  /* fundamental file system block size */
	long	f_iosize;	  /* optimal transfer block size */
	long	f_blocks;	  /* total data blocks in file system */
	long	f_bfree;	  /* free blocks in fs */
	long	f_bavail;	  /* free blocks avail to non-superuser */
	long	f_files;	  /* total file nodes in file system */
	long	f_ffree;	  /* free file nodes in fs */
	fsid_t	f_fsid;		  /* file system id */
	long	f_spare[6];	  /* spare for later */
	char	f_fstypename[MFSNAMELEN+1]; /* fs type name (inc. null) */
	char	f_mntonname[MNAMELEN];	/* mount point */
	char	f_mntfromname[MNAMELEN]; /* mounted filesystem */
};
.Ed
.Pp
Fields that are undefined for a particular file system are set to -1.
.Fn Fstatfs
returns the same information about an open file referenced by descriptor
.Fa fd .
.Sh RETURN VALUES
Upon successful completion, a value of 0 is returned.
Otherwise, -1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
.Fn Statfs
fails if one or more of the following are true:
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix of
.Fa Path
is not a directory.
.It Bq Er ENAMETOOLONG
The length of a component of
.Fa path
exceeds 
.Dv {NAME_MAX}
characters, or the length of
.Fa path
exceeds 
.Dv {PATH_MAX}
characters.
.It Bq Er ENOENT
The file referred to by
.Fa path
does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix of
.Fa path .
.It Bq Er ELOOP
Too many symbolic links were encountered in translating
.Fa path .
.It Bq Er EFAULT
.Fa Buf
or
.Fa path
points to an invalid address.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.El
.Pp
.Fn Fstatfs
fails if one or more of the following are true:
.Bl -tag -width Er
.It Bq Er EBADF
.Fa Fd
is not a valid open file descriptor.
.It Bq Er EFAULT
.Fa Buf
points to an invalid address.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.El
.Sh HISTORY
The
.Fn statfs
function first appeared in 4.4BSD.