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.\"	@(#)getfsstat.2	8.1 (Berkeley) 6/9/93
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.Dd Oct 28, 2008
.Dt GETFSSTAT 2
.Os
.Sh NAME
.Nm getfsstat
.Nd get list of all mounted file systems
.Sh SYNOPSIS
.Fd #include <sys/param.h>
.Fd #include <sys/ucred.h>
.Fd #include <sys/mount.h>
.Ft int
.Fn getfsstat "struct statfs *buf" "int bufsize" "int flags"
.Sh TRANSITIIONAL SYNOPSIS (NOW DEPRECATED)
.Ft int
.br
.Fn getfsstat64 "struct statfs64 *buf" "int bufsize" "int flags" ;
.Sh DESCRIPTION
The
.Fn getfsstat
function returns information about all mounted file systems.
The
.Fa buf
argument is a pointer to an array of
.Xr statfs
structures.
.Pp
As of Mac OS X 10.6, the default size of the
.Ft ino_t
type is 64 bits (the macro
.Dv _DARWIN_FEATURE_64_BIT_INODE
will be defined).
While there is no
.Ft ino_t
type used in the
.Xr statfs
structure, the changes to
.Fn getfsstat
are grouped together with the 64-bit inode changes.
The string fields in the
.Xr statfs
structure are larger and the variant symbol
.Li _getfsstat$INODE64
will be automatically used.
The
.Xr statfs
structure is defined as:
.Bd -literal
typedef struct { int32_t val[2]; } fsid_t;

#define MFSTYPENAMELEN  16 /* length of fs type name including null */
#define MAXPATHLEN      1024	
#define MNAMELEN        MAXPATHLEN

struct statfs { /* when _DARWIN_FEATURE_64_BIT_INODE is defined */
    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
(In 10.5, 64-bit
.Ft ino_t ,
larger
.Xr statfs
structure and variant symbol were available if the macro
.Dv _DARWIN_USE_64_BIT_INODE
is defined before any header files are included; this macro is optional in
10.6.)
.Pp
If the macro
.Dv _DARWIN_NO_64_BIT_INODE
is defined before any header files are included, or if the deployment target
is less than 10.6, the legacy
.Xr statfs
structure will be in effect.
The
.Ft ino_t
type will be 32 bits (the
.Dv _DARWIN_FEATURE_64_BIT_INODE
macro will not be defined), the strings in the
.Xr statfs
structure will be their smaller legacy size (and long mount paths may no longer
fit) and the undecorated symbol
.Li _getfsstat
will be used.
This legacy
.Fa statfs
structure is defined as:
.Bd -literal
#define MFSNAMELEN      15 /* length of fs type name, not inc. nul */
#define MNAMELEN        90 /* length of buffer for returned name */

struct statfs { /* when _DARWIN_FEATURE_64_BIT_INODE is NOT defined */
    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 */
};
.Ed
.Pp
Fields that are undefined for a particular file system are set to -1.
The buffer is filled with an array of
.Fa statfs
structures, one for each mounted file system
up to the size specified by
.Fa bufsize .
.Pp
If
.Fa buf
is given as NULL,
.Fn getfsstat
returns just the number of mounted file systems.
.Pp
If
.Fa flags
is set to
.Dv MNT_NOWAIT ,
.Fn getfsstat
will directly return the information retained in the kernel
to avoid delays caused by waiting for updated information from
a file system that is perhaps temporarily unable to respond.
Some of the information returned may be out of date, however; if
.Fa flags
is set to
.Dv MNT_WAIT
or
.Dv MNT_DWAIT
instead,
.Fn getfsstat
will request updated information from each mounted filesystem before
returning.
.Sh RETURN VALUES
Upon successful completion, the number of 
.Fa statfs
structures is returned.
Otherwise, -1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
.Fn Getfsstat
fails if one or more of the following are true:
.Bl -tag -width Er
.It Bq Er EFAULT
The
.Fa buf
argument 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 TRANSITIONAL DESCRIPTION (NOW DEPRECATED)
The
.Fn getfsstat64
routine is equivalent to the default
.Fn getfstat
(when
.Dv _DARWIN_FEATURE_64_BIT_INODE
is defined), so there is no longer any reason to use it (it will be removed
in the future).
.Sh SEE ALSO
.Xr statfs 2 ,
.Xr fstab 5 ,
.Xr mount 8
.Sh HISTORY
The
.Fn getfsstat
function first appeared in 4.4BSD.