SunOS man pages : devlinks (1)
Maintenance 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 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,
since drvconfig(1M) builds the kernel data structures and
the /devices tree.
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 separated 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 /dev-
ices tree entry name that occurs before the first `@'
or `:' character.
addr[n]
The address portion of a node name. This is the por-
tion of a node name that occurs between the `@' and
the `:' characters. It is possible that a node may
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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 partic-
ular comma-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 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 com-
ponent 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 com-
ponent.
\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
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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 con-
tain any of the other escape-sequences. It provides a
way to specify an alias of a particular /dev name.
OPTIONS
-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 sup-
plied 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 rea-
son it prints an error-message and continues with the
current rule.
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If it cannot read necessary data it prints an error message
and continues with the next table-file line.
EXAMPLES
Example 1: Examples of /etc/devlink.tab fields
Example /etc/devlink.tab fields are:
type=pseudo;name=win win\M0
type=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 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 attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
SEE ALSO
devfsadm(1M), ddi_create_minor_node(9F), disks(1M),
drvconfig(1M), ports(1M), tapes(1M), attributes(5)
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.
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