ChorusOS man pages section 4CC: Files

fstab(4CC)

NAME

fstab- static information about the filesystems

SYNOPSIS

#include <fstab.h>

DESCRIPTION

The file fstab contains descriptive information about the various file systems. It is only read by programs, and not written to; 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(1M) iterates sequentially iterate through fstab.

The first field, fs_spec, describes the block special device or remote filesystem to be mounted. For filesystems of type UFS, 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 an "r" after the last "/" in the special file name.

The second field, fs_file, describes the mount point for the filesystem. For swap partitions, this field should be specified as "none".

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

ufs: a local UNIX filesystem
msdosfs: a local DOS filesystem, see RESTRICTIONS for ChorusOS.
nfs: a Sun Microsystems compatible Network File System
swap: a disk partition to be used for swapping

The fourth field, fs_mntops, describes the mount options associated with the filesystem. It is formatted as a list of options separated by commas (","). It contains at a minimum, the type of mount (see fs_type below) plus any additional options appropriate to the filesystem type.

If the options "userquota" or "groupquota" are specified, the filesystem is automatically processed by the quotacheck (see RESTRICTIONS for ChorusOS) command, and user and/or group disk quotas are enabled using quotaon. By default, filesystem quotas are maintained in files named quota.user and quota.group 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 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", the filesystem whose name is given in the fs_file field should be mounted read-write or read-only on the special file specified. If fs_type is "sw", the special file is made available as a piece of swap space by the swapon(1M) command at the end of the system reboot procedure. Fields other than fs_spec and fs_type are not used (see RESTRICTIONS for ChorusOS). If fs_type is specified as "xx" the entry is ignored. This is useful for showing disk partitions which are currently unused.

The fifth field, fs_freq, is used for filesystems by the dump (see RESTRICTIONS for ChorusOS) 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 not dump the filesystem.

The sixth field, fs_passno, is used by the fsck(1M) program to determine the order in which filesystem checks are done at reboot time. The root filesystem should be specified with an fs_passno of 1, and other filesystems should have an 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 use the parallelism available in the hardware. If the sixth field is not present or zero, a value of zero is returned and fsck will not check the filesystem.

#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 */
};

FILES

/etc/fstab

HISTORY

This file format appeared in 4.0 BSD.

RESTRICTIONS FOR ChorusOS

Utilities for checking quotas, quotacheck and quotaon, are not implemented.

swapon(1M) is implemented as a built-in C_INIT(1M) system actor command.

dump is not implemented.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving

ChorusOS 4.0 Last Revised December 1999