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@(#)fstab.5 6.1 (Berkeley) 05/15/85

C 4 fstab - static information about the filesystems #include <fstab.h> The file /etc/fstab contains descriptive information about the various file systems. /etc/fstab is only read by programs, and not written; it is the duty of the system administrator to properly create and maintain this file. The order of records in /etc/fstab is important because fsck, mount, and umount sequentially iterate through /etc/fstab doing their thing.

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.

If fs_type is ``rw'' or ``ro'' then the file system 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 ``rq'', then the file system is normally mounted read-write with disk quotas enabled. The fs_freq field is used for these file systems by the dump (8) command to determine which file systems need to be dumped. The fs_passno field is used by the fsck (8) program to determine the order in which file system checks are done at reboot time. The root file system should be specified with a fs_passno of 1, and other file systems should have larger numbers. File systems within a drive should have distinct numbers, but file systems on different drives can be checked on the same pass to utilize parallelism available in the hardware.

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 not used in this case.

If fs_type is ``rq'' then at boot time the file system is automatically processed by the quotacheck (8) command and disk quotas are then enabled with quotaon (8). File system quotas are maintained in a file ``quotas'', which is located at the root of the associated file system.

If fs_type is specified as ``xx'' the entry is ignored. This is useful to show disk partitions which are currently not used.

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

struct fstab {
 char *fs_spec; /* block special device name */
 char *fs_file; /* file system path prefix */
 char *fs_type; /* rw,ro,sw or xx */
 int fs_freq; /* dump frequency, in days */
 int fs_passno; /* pass number on parallel dump */
};

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

/etc/fstab getfsent(3X)