marry(HW)

marry -- marriage driver

Description

The marriage driver allows a regular file to be treated as a device. It does not drive any hardware directly, but it redirects reads and writes on its device to the associated regular file.

marry(ADM) uses the marriage driver to associate a block special device file with a regular file. The regular file may then be accessed through the block device node created below the /dev/marry directory, or through a character device node.

swap(ADM) uses marry to allow a regular file to act as a block device for swapping. marry may also be used to allow a regular file to act as a block device for mounting.

The only permanent device file associated with the marry driver is /dev/rmarry, a character device node that allows control of the driver through ioctl(S) calls. The default permissions on this node are 666, owner root, and group root; these may be changed by root to restrict the use of the marry command by other users. For example, a permission of 664 would only allow root to make and dissolve marriages; all other users would only be allowed to list the married files.

If you change the permissions on /dev/rmarry, you should also edit /etc/conf/node.d/marry so that the new permissions take effect whenever the kernel environment is rebuilt.

Limitations

By default, a maximum of 24 concurrent marriages are allowed. To raise this limit (up to 255), edit /etc/conf/pack.d/marry/space.c to define NMARRIAGES as required, then relink the kernel.

The marriage driver should only be used through marry; this maintains the /dev/marry hierarchy of block device nodes.

Files

/etc/conf/pack.d/marry/Driver.o: the marriage driver
/etc/conf/pack.d/marry/space.c: defines the number of marriages allowed: minimum 0, default 24, maximum 255
/etc/conf/pack.d/marry/stubs.c: stub routines if the marriage driver is configured out of the kernel
/etc/conf/sdevice.d/marry: configures the marriage driver in (Y) or out (N) of the kernel
/etc/conf/node.d/marry: specifies permissions for /dev/rmarry when the kernel is rebuilt
/etc/conf/cf.d/mdevice: defines the major number of the block and character marry devices; the default is 76
/dev/rmarry: permanent character device node (minor 0) used by marry when adding, deleting, or listing marriages using ioctl.
/dev/marry/path: block device node (minor number 1 or greater) temporarily associated by the marriage driver with the regular file path
/usr/include/marry.h: header file for the marry driver, its space.c file and utility

marry(HW)

Description

Limitations

Files

See also