fstab(5)
NAME
fstab − static information about the filesystems
SYNTAX
#include <fstab.h>
DESCRIPTION
The /etc/fstab file 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 the fsck, mount, and umount commands sequentially iterate through /etc/fstab.
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. The fs_freq field is currently unused. The fs_passno field is used by the fsck(8) program with the ‘-p‘ option 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 swap space segment. The fields other than fs_spec and fs_type are not used in this case.
If fs_type is specified as “xx” the entry is ignored. This is useful to show disk partitions which are currently not used.
#defineFSTAB_RW "rw"/* read-write device */
#defineFSTAB_RO "ro"/* read-only device */
#defineFSTAB_SW "sw"/* swap device */
#defineFSTAB_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 */
intfs_freq; /* dump frequency in days (not used) */
intfs_passno; /* pass number on parallel dump, (used
only with fsck -p option) */
};
The proper way to read records from /etc/fstab is to use the routines getfsent, getfsspec, getfstype, and getfsfile.
FILES
/etc/fstab