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GETFSSTAT(2)                               BSD System Calls Manual                              GETFSSTAT(2)

NAME
     getfsstat -- get list of all mounted file systems

SYNOPSIS
     #include <sys/param.h>
     #include <sys/ucred.h>
     #include <sys/mount.h>

     int
     getfsstat(struct statfs *buf, int bufsize, int flags);

TRANSITIIONAL SYNOPSIS (NOW DEPRECATED)
     int
     getfsstat64(struct statfs64 *buf, int bufsize, int flags);

DESCRIPTION
     The getfsstat() function returns information about all mounted file systems.  The buf argument is a
     pointer to an array of statfs structures.

     As of Mac OS X 10.6, the default size of the ino_t type is 64 bits (the macro
     _DARWIN_FEATURE_64_BIT_INODE will be defined).  While there is no ino_t type used in the statfs struc-ture, structure,
     ture, the changes to getfsstat() are grouped together with the 64-bit inode changes.  The string fields
     in the statfs structure are larger and the variant symbol _getfsstat$INODE64 will be automatically
     used.  The statfs structure is defined as:

     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 */
     };

     (In 10.5, 64-bit ino_t, larger statfs structure and variant symbol were available if the macro
     _DARWIN_USE_64_BIT_INODE is defined before any header files are included; this macro is optional in
     10.6.)

     If the macro _DARWIN_NO_64_BIT_INODE is defined before any header files are included, or if the deploy-ment deployment
     ment target is less than 10.6, the legacy statfs structure will be in effect.  The ino_t type will be
     32 bits (the _DARWIN_FEATURE_64_BIT_INODE macro will not be defined), the strings in the statfs struc-ture structure
     ture will be their smaller legacy size (and long mount paths may no longer fit) and the undecorated
     symbol _getfsstat will be used.  This legacy statfs structure is defined as:

     #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 */
     };

     Fields that are undefined for a particular file system are set to -1.  The buffer is filled with an
     array of statfs structures, one for each mounted file system up to the size specified by bufsize.

     If buf is given as NULL, getfsstat() returns just the number of mounted file systems.

     If flags is set to MNT_NOWAIT, 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 temporar-ily temporarily
     ily unable to respond.  Some of the information returned may be out of date, however; if flags is set
     to MNT_WAIT or MNT_DWAIT instead, getfsstat() will request updated information from each mounted
     filesystem before returning.

RETURN VALUES
     Upon successful completion, the number of statfs structures is returned.  Otherwise, -1 is returned and
     the global variable errno is set to indicate the error.

ERRORS
     Getfsstat() fails if one or more of the following are true:

     [EFAULT]           The buf argument points to an invalid address.

     [EIO]              An I/O error occurred while reading from or writing to the file system.

TRANSITIONAL DESCRIPTION (NOW DEPRECATED)
     The getfsstat64() routine is equivalent to the default getfstat() (when _DARWIN_FEATURE_64_BIT_INODE is
     defined), so there is no longer any reason to use it (it will be removed in the future).

SEE ALSO
     statfs(2), fstab(5), mount(8)

HISTORY
     The getfsstat() function first appeared in 4.4BSD.

BSD                                             Oct 28, 2008                                             BSD