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 /dev-
ices 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 createdaccording 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 containa hash character (`#') as their first character, are
allowed. Each entry must contain at least two fields, but may contain three fields. Fields are separated by single TAB characters. The fields are:devfs-spec Specification of devinfo nodes that will
have links created for them. This specifi-
cation consists of one or more keyword-
value pairs, where the keyword isseparated 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. Pos-
sible values are specified inddi_create_minor_node(9F)
name The name of the node. This is the portion of the /devices tree entry name that occursSunOS 5.11 Last change: 15 Jul 2002 1
System Administration Commands devlinks(1M)
before the first `@' or `:' character. addr[n] The address portion of a node name. This is the portion of a node name that occurs betweenthe `@' and the `:' charac-
ters. It is possible that a node may have a name without an address part, which is thecase for many of the pseudo-
device nodes. If a number isgiven after the addr it speci-
fies a match of a particularcomma-separated subfield of
the address field: addr1 matches the first subfield, 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 nodename - the portion of the name
after the `:'. As with addr above, a number after theminor keyword specifies a sub-
field 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. Thisfield allows devlinks to determine match-
ing /dev names for the /devices nodes it has found. The specification of this fielduses 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 ofthe name before the counter must be speci-
fied 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 theSunOS 5.11 Last change: 15 Jul 2002 2
System Administration Commands devlinks(1M)
/devices/-tree
The possible escape-sequences are:
\D Substitute the device-name (name)
portion of the correspondingdevinfo node-name.
\An Substitute the nth component of the address component of the corresponding devinfo node name.Sub-components 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-components are separated by
commas, and sub-component 0 is the
whole minor component. \Nn Substitute the value of a 'counter' starting at n. There canbe only one counter for each dev-
spec, and counter-values will be
selected so they are as low as possible while not colliding withalready-existing link names.
In a dev-spec the counter sequence
should not be followed by a digit, either explicitly or as a resultof another escape-sequence expan-
sion. If this occurs, it would not be possible to correctly matchalready-existing links to their
counter entries, since it would not be possible to unambiguouslyparse 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 maycontain a counter escape-sequence (as
described for the dev-spec field) but may
SunOS 5.11 Last change: 15 Jul 2002 3
System Administration Commands devlinks(1M)
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 thefilename 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 toinstruct devlinks just to perform a partic-
ular 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 onto 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 rea-
son it prints an error-message and continues with the
current rule. If it cannot read necessary data it prints an error messageand continues with the next table-file line.
EXAMPLES
Example 1 Using the /etc/devlink.tab FieldsSunOS 5.11 Last change: 15 Jul 2002 4
System Administration Commands devlinks(1M)
The following are examples of the /etc/devlink.tab fields: type=pseudo;name=win win\M0type=ddi_display framebuffer/\M0 fb\N0
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 typeddi_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 attri-
butes:____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcs ||_____________________________|_____________________________|
SEE ALSO
devfsadm(1M), attributes(5), devfs(7FS),ddi_create_minor_node(9F)
SunOS 5.11 Last change: 15 Jul 2002 5
System Administration Commands devlinks(1M)
BUGS
It is very easy to construct mutually-contradictory link
specifications, or specifications that can never be matched. The program does not check for these conditions.SunOS 5.11 Last change: 15 Jul 2002 6