#include <fstab.h>

DESCRIPTION

     The file fstab contains descriptive information about the various file
     systems.  fstab is only read by programs, and not written; it is the duty
     of the system administrator to properly create and maintain this file.
     Each filesystem is described on a separate line; fields on each line are
     separated by tabs or spaces.  The order of records in fstab is important
     because fsck(8),  mount(8),  and umount(8) sequentially iterate through
     fstab doing their thing.

     The first field, (fs_spec), describes the block special device or remote
     filesystem to be mounted.  For filesystems of type ffs, the special file
     name is the block special file name, and not the character special file
     name.  If a program needs the character special file name, the program
     must create it by appending a ``r'' after the last ``/'' in the special
     file name.

     The second field, (fs_file), describes the mount point for the filesys-
     tem.  For swap partitions, this field should be specified as ``none''.

     The third field, (fs_vfstype), describes the type of the filesystem.  The
     system currently supports eleven types of filesystems:

           adosfs  An AmigaDOS filesystem

           cd9660  an ISO 9660 CD-ROM filesystem

           fdesc   an implementation of /dev/fd

           ffs     a local filesystem

           kernfs  various and sundry kernel statistics

           mfs     a local memory-based filesystem

           msdos   a MSDOS ``FAT'' filesystem

           nfs     a Sun Microsystems compatible ``Network File System''

           procfs  a local filesystem of process information

           swap    a disk partition to be used for swapping

           union   a translucent filesystem

     The fourth field, (fs_mntops), describes the mount options associated
     with the filesystem.  It is formatted as a comma separated list of op-
     tions.  It contains at least the type of mount (see fs_type below) plus
     any additional options appropriate to the filesystem type.

     The option ``auto'' can be used in the ``noauto'' form to cause a file

     The type of the mount is extracted from the fs_mntops field and stored
     separately in the fs_type field (it is not deleted from the fs_mntops
     field).  If fs_type is ``rw'' or ``ro'' then the filesystem whose name is
     given in the fs_file field is normally mounted read-write or read-only on
     the specified special file.  If fs_type is ``sw'' then the special file
     is made available as a piece of swap space by the swapon(8) command at
     the end of the system reboot procedure.  The fields other than fs_spec
     and fs_type are unused.  If fs_type is specified as ``xx'' the entry is
     ignored.  This is useful to show disk partitions which are currently un-
     used.

     The fifth field, (fs_freq), is used for these filesystems by the dump(8)
     command to determine which filesystems need to be dumped.  If the fifth
     field is not present, a value of zero is returned and dump will assume
     that the filesystem does not need to be dumped.

     The sixth field, (fs_passno), is used by the fsck(8) program to determine
     the order in which filesystem checks are done at reboot time.  The root
     filesystem should be specified with a fs_passno of 1, and other filesys-
     tems should have a fs_passno of 2.  Filesystems within a drive will be
     checked sequentially, but filesystems on different drives will be checked
     at the same time to utilize parallelism available in the hardware.  If
     the sixth field is not present or zero, a value of zero is returned and
     fsck will assume that the filesystem does not need to be checked.

     #define FSTAB_RW        "rw"    /* read-write device */
     #define FSTAB_RO        "ro"    /* read-only device */
     #define FSTAB_SW        "sw"    /* swap device */
     #define FSTAB_XX        "xx"    /* ignore totally */

     struct fstab {
             char    *fs_spec;       /* block special device name */
             char    *fs_file;       /* filesystem path prefix */
             char    *fs_vfstype;    /* type of filesystem */
             char    *fs_mntops;     /* comma separated mount options */
             char    *fs_type;       /* rw, ro, sw, or xx */
             int     fs_freq;        /* dump frequency, in days */
             int     fs_passno;      /* pass number on parallel fsck */
     };

     The proper way to read records from fstab is to use the routines
     getfsent(3),  getfsspec(3),  getfstype(3),  and getfsfile(3).

FILES

     /etc/fstab  The file fstab resides in /etc.

SEE ALSO

     getfsent(3)

HISTORY

     The fstab file format appeared in 4.0BSD.