devlinks(1M)						  System Administration Commands					      devlinks(1M)

NAME

       devlinks - adds /dev entries for miscellaneous devices and pseudo-devices

SYNOPSIS

       /usr/sbin/devlinks [-d] [-r rootdir] [-t table-file]

DESCRIPTION

       devfsadm(1M) is now the preferred command for /dev and /devices and should be used instead of devlinks.

       devlinks  creates  symbolic  links  from the /dev directory tree to the actual block- and character-special device nodes under the /devices
       directory tree. The links are created according to specifications found in the table-file (by default /etc/devlink.tab).

       devlinks is called each time the system is reconfiguration-booted, and can only be run after drvconfig(1M) is run.

       The  table-file (normally /etc/devlink.tab) is an ASCII file, with one line per record. Comment lines, which must contain a hash  character
       (`#')  as  their first character, are allowed. Each entry must contain at least two fields, but may contain three  fields. Fields are sepa-
       rated by single TAB characters.

       The fields are:

       devfs-spec	       Specification of devinfo nodes that will have links created for them. This specification consists of  one  or  more
			       keyword-value  pairs, where the keyword is separated from the value by an equal-sign (`='), and keyword-value pairs
			       are separated from one another by semicolons.

			       The possible keywords are:

			       type	       The devinfo device type. Possible values are specified in ddi_create_minor_node(9F)

			       name	       The name of the node. This is the portion of the /devices tree entry name that  occurs  before  the
					       first `@' or `:' character.

			       addr[n]	       The  address portion of a node name. This is the portion of a node name that occurs between the `@'
					       and the `:' characters. It is possible that a node may have a name without an address  part,  which
					       is the case for many of the pseudo-device nodes. If a number is given after the addr it specifies a
					       match of a particular comma-separated subfield of the address field: addr1 matches the  first  sub-
					       field, addr2 matches the second, and so on. addr0 is the same as  addr and matches the whole field.

			       minor[n]        The  minor  portion  of	a node name - the portion of the name after the `:'. As with addr above, a
					       number after the minor keyword specifies a subfield to match.

			       Of these four specifications, only the type specification must always be present.

       name		       Specification of the /dev links that correspond to the devinfo nodes.  This  field  allows  devlinks  to  determine
			       matching  /dev  names for the /devices nodes it has found. The specification of this field uses escape-sequences to
			       allow portions of the /devices name to be included in the /dev name, or to allow a counter to be used  in  creating
			       node  names.  If  a  counter is used to create a name, the portion of the name before the counter must be specified
			       absolutely, and all names in the /dev/-subdirectory that match (up to and including the counter) are considered	to
			       be  subdevices  of  the	same device. This means that they should all point to the same directory, name and address
			       under the /devices/-tree

			       The possible escape-sequences are:

			       D	Substitute the device-name (name) portion of the corresponding devinfo node-name.

			       An	Substitute the nth component of the address component of the corresponding devinfo node  name.	Sub-compo-
					nents are separated by commas, and sub-component 0 is the whole address component.

			       Mn	Substitute the nth sub-component of the minor component of the corresponding devinfo node name. Sub-compo-
					nents are separated by commas, and sub-component 0 is the whole minor component.

			       Nn	Substitute the value of a 'counter' starting at n. There can be only one counter for  each  dev-spec,  and
					counter-values	will  be selected so they are as low as possible while not colliding with already-existing
					link names.

					In a dev-spec the counter sequence should not be followed by a digit, either explicitly or as a result	of
					another  escape-sequence  expansion.  If this occurs, it would not be possible to correctly match already-
					existing links to their counter entries, since it  would  not  be  possible  to  unambiguously	parse  the
					already-existing /dev-name.

       extra-dev-link	       Optional  specification	of  an	extra  /dev link that points to the initial /dev link (specified in field 2). This
			       field may contain a counter escape-sequence (as described for the dev-spec field) but may not contain  any  of  the
			       other escape-sequences. It provides a way to specify an alias of a particular /dev name.

OPTIONS

       The following options are supported:

       -d	       Debugging mode - print out all  devinfo nodes found, and indicate what links would be created, but do not do anything.

       -r rootdir      Use  rootdir  as the root of the /dev and /devices directories under which the device nodes and links are created. Changing
		       the root directory does not change the location of the /etc/devlink.tab default table, nor is the root directory applied to
		       the filename supplied to the -t option.

       -t table-file   Set  the  table	file  used  by	devlinks  to  specify  the  links  that  must  be  created.  If  this option is not given,
		       /etc/devlink.tab is used. This option gives a way to instruct devlinks just to perform a particular piece  of  work,  since
		       just the links-types that devlinks is supposed to create can be specified in a command-file and fed to devlinks.

ERRORS

       If   devlinks finds an error in a line of the table-file it prints a warning message on its standard output and goes on to the next line in
       the table-file without performing any of the actions specified by the erroneous rule.

       If it cannot create a link for some filesystem-related reason it  prints an error-message and continues with the current rule.

       If it cannot read necessary data it prints an error message and continues with the next table-file line.

EXAMPLES

       Example 1: Using the /etc/devlink.tab Fields

       The following are examples of the /etc/devlink.tab fields:

       type=pseudo;name=win	winM0
       type=ddi_display    framebuffer/M0     fbN0

       The first example states that all devices of type  pseudo with a name component of  win will be linked to /dev/winx, where x is the  minor-
       component of the devinfo-name (this is always a single-digit number for the win driver).

       The  second example states that all devinfo nodes of type  ddi_display will be linked to entries under the /dev/framebuffer directory, with
       names identical to the entire minor component of the /devices name. In addition an extra link will be created pointing from /dev/fbn to the
       entry under /dev/framebuffer. This entry will use a counter to end the name.

FILES

       /dev		       entries for the miscellaneous devices for general use

       /devices 	       device nodes

       /etc/devlink.tab        the default rule-file

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       devfsadm(1M), attributes(5), devfs(7FS), ddi_create_minor_node(9F)

BUGS

       It is very easy to construct mutually-contradictory link specifications, or specifications that can never be matcshed. The program does not
       check for these conditions.

SunOS 5.10							    15 Jul 2002 						      devlinks(1M)