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.\"	@(#)statfs.2	8.3 (Berkeley) 2/11/94
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.Dd February 11, 1994
.Dt STATFS 2
.Os
.Sh NAME
.Nm statfs,
.Nm statfs64,
.Nm fstatfs,
.Nm fstatfs64
.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 statfs64 "const char *path" "struct statfs64 *buf"
.Ft int
.Fn fstatfs "int fd" "struct statfs *buf"
.Ft int
.Fn fstatfs64 "int fd" "struct statfs64 *buf"
.Sh DESCRIPTION
.Fn Statfs
returns information about a mounted file system.
.Fa Path
is the path name of any file within the mounted file system.
.Fa Buf
is a pointer to a 
.Fa statfs
or
.Fa statfs64
structure defined as follows:
.Bd -literal
typedef struct { int32_t val[2]; } fsid_t;

#define MFSNAMELEN      15 /* length of fs type name, not inc. nul */
#define MNAMELEN        90 /* length of buffer for returned name */
#define MFSTYPENAMELEN  16 /* length of fs type name including null */
#define MAXPATHLEN      1024	

struct statfs {
    short   f_otype;	/* type of file system (reserved: zero) */
    short   f_oflags;	/* copy of mount flags (reserved: zero) */
    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 */
    uid_t   f_owner;	/* user that mounted the file system */
    short   f_reserved1;	/* reserved for future use */
    short   f_type;	/* type of file system (reserved) */
    long    f_flags;	/* copy of mount flags (reserved) */
    long    f_reserved2[2];	/* reserved for future use */
    char    f_fstypename[MFSNAMELEN]; /* fs type name */
    char    f_mntonname[MNAMELEN];    /* directory on which mounted */
    char    f_mntfromname[MNAMELEN];  /* mounted file system */
    char    f_reserved3;	/* reserved for future use */
    long    f_reserved4[4];	/* reserved for future use */
};

struct statfs64 {
    uint32_t        f_bsize;        /* fundamental file system block size */ 
    int32_t         f_iosize;       /* optimal transfer block size */ 
    uint64_t        f_blocks;       /* total data blocks in file system */ 
    uint64_t        f_bfree;        /* free blocks in fs */ 
    uint64_t        f_bavail;       /* free blocks avail to non-superuser */ 
    uint64_t        f_files;        /* total file nodes in file system */ 
    uint64_t        f_ffree;        /* free file nodes in fs */ 
    fsid_t          f_fsid;         /* file system id */ 
    uid_t           f_owner;        /* user that mounted the filesystem */ 
    uint32_t        f_type;         /* type of filesystem */ 
    uint32_t        f_flags;        /* copy of mount exported flags */ 
    uint32_t        f_fssubtype;    /* fs sub-type (flavor) */ 
    char            f_fstypename[MFSTYPENAMELEN];   /* fs type name */ 
    char            f_mntonname[MAXPATHLEN];        /* directory on which mounted */ 
    char            f_mntfromname[MAXPATHLEN];      /* mounted filesystem */ 
    uint32_t        f_reserved[8];  /* For future use */ 
};
.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 FLAGS
.Bl -tag -width MNT_UNKOWNPERMISSIONS
These are some of the flags that may be present in the f_flags field. 
.It Dv MNT_RDONLY
A read-only filesystem
.It Dv MNT_SYNCHRONOUS
File system is written to synchronously
.It Dv MNT_NOEXEC
Can't exec from filesystem
.It Dv MNT_NOSUID
Setuid bits are not honored on this filesystem
.It Dv MNT_NODEV
Don't interpret special files
.It Dv MNT_UNION
Union with underlying filesysten
.It Dv MNT_ASYNC
File system written to asynchronously
.It Dv MNT_EXPORTED
File system is exported
.it Dv MNT_LOCAL
File system is stored locally
.It Dv MNT_QUOTA
Quotas are enabled on this file system
.It Dv MNT_ROOTFS
This file system is the root of the file system
.It Dv MNT_DOVOLFS
File system supports volfs
.It Dv MNT_DONTBROWSE
File system is not appropriate path to user data
.It Dv MNT_UNKNOWNPERMISSIONS
VFS will ignore ownership information on filesystem objects
.It Dv MNT_AUTOMOUNTED
File system was mounted by automounter
.It Dv MNT_JOURNALED
File system is journaled
.It Dv MNT_DEFWRITE
File system should defer writes
.It Dv MNT_MULTILABEL
MAC support for individual labels
.El
.Sh CAVEATS
In Mac OS X versions before 10.4, f_iosize is 4096. On these older
systems, use MAXBSIZE instead.
.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. The
.Fn statfs64
and 
.Fn fstatfs64
first appeared in Max OS X 10.5 (Leopard).