4.3BSD-Reno/share/man/cat5/fstab.0
FSTAB(5) 1990 FSTAB(5)
NNAAMMEE
fstab - static information about the filesystems
SSYYNNOOPPSSIISS
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The file /_e_t_c/_f_s_t_a_b contains descriptive information about
the various file systems. /_e_t_c/_f_s_t_a_b is only read by pro-
grams, 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 /_e_t_c/_f_s_t_a_b is important because _f_s_c_k, _m_o_u_n_t, and
_u_m_o_u_n_t sequentially iterate through /_e_t_c/_f_s_t_a_b doing their
thing.
The first field, (_f_s__s_p_e_c), describes the block special dev-
ice or remote filesystem to be mounted. For filesystems of
type uuffss, 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, (_f_s__f_i_l_e), describes the mount point for
the filesystem. For swap partitions, this field should be
specified as ``none''.
The third field, (_f_s__v_f_s_t_y_p_e), describes the type of the
filesystem. The system currently supports four types of
filesystems:
uuffss a local UNIX filesystem
mmffss a local memory-based UNIX filesystem
nnffss a Sun Microsystems compatible ``Network File Sys-
tem''
sswwaapp a disk partition to be used for swapping
The fourth field, (_f_s__m_n_t_o_p_s), describes the mount options
associated with the filesystem. It is formatted as a comma
separated list of options. It contains at least the type of
mount (see _f_s__t_y_p_e below) plus any additional options
appropriate to the filesystem type.
If the options ``userquota'' and/or ``groupquota'' are
specified, the filesystem is automatically processed by the
_q_u_o_t_a_c_h_e_c_k(8) command, and user and/or group disk quotas are
enabled with _q_u_o_t_a_o_n(8). By default, filesystem quotas are
Printed 7/27/90 June 1
FSTAB(5) 1990 FSTAB(5)
maintained in files named _q_u_o_t_a._u_s_e_r and _q_u_o_t_a._g_r_o_u_p which
are located at the root of the associated filesystem. These
defaults may be overridden by putting an equal sign and an
alternative absolute pathname following the quota option.
Thus, if the user quota file for /tmp is stored in
/var/quotas/tmp.user, this location can be specified as:
userquota=/var/quotas/tmp.user
The type of the mount is extracted from the _f_s__m_n_t_o_p_s field
and stored separately in the _f_s__t_y_p_e field (it is not
deleted from the _f_s__m_n_t_o_p_s field). If _f_s__t_y_p_e is ``rw'' or
``ro'' then the filesystem whose name is given in the
_f_s__f_i_l_e field is normally mounted read-write or read-only on
the specified special file. If _f_s__t_y_p_e is ``sw'' then the
special file is made available as a piece of swap space by
the _s_w_a_p_o_n(8) command at the end of the system reboot pro-
cedure. The fields other than _f_s__s_p_e_c and _f_s__t_y_p_e are
unused. If _f_s__t_y_p_e is specified as ``xx'' the entry is
ignored. This is useful to show disk partitions which are
currently unused.
The fifth field, (_f_s__f_r_e_q), is used for these filesystems by
the _d_u_m_p(8) command to determine which filesystems need to
be dumped. If the fifth field is not present, a value of
zero is returned and _d_u_m_p will assume that the filesystem
does not need to be dumped.
The sixth field, (_f_s__p_a_s_s_n_o), is used by the _f_s_c_k(8) program
to determine the order in which filesystem checks are done
at reboot time. The root filesystem should be specified
with a _f_s__p_a_s_s_n_o of 1, and other filesystems should have a
_f_s__p_a_s_s_n_o 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 _f_s_c_k 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 dump */
Printed 7/27/90 June 2
FSTAB(5) 1990 FSTAB(5)
};
The proper way to read records from /_e_t_c/_f_s_t_a_b is to use the
routines getfsent(), getfsspec(), getfstype(), and getfs-
file().
FFIILLEESS
/etc/fstab
SSEEEE AALLSSOO
getfsent(3)
Printed 7/27/90 June 3