DEVLINKS(1M)DEVLINKS(1M)NAMEdevlinks - adds /dev entries for miscellaneous devices and pseudo-
devices
SYNOPSIS
/usr/sbin/devlinks [-d] [-r rootdir] [-t table-file]
DESCRIPTIONdevfsadm(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 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_cre‐
ate_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 `:' char‐
acter.
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 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 specifi‐
cation 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-components are separated by commas,
and sub-component 0 is the whole address com‐
ponent.
\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 compo‐
nent.
\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 col‐
liding 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 expan‐
sion. If this occurs, it would not be possi‐
ble 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 pro‐
vides 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 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 reason it prints
an error-message and continues with the current rule.
If it cannot read necessary data it prints an error message and contin‐
ues 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 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-com‐
ponent 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
SEE ALSOdevfsadm(1M), attributes(5), devfs(7FS), ddi_create_minor_node(9F)BUGS
It is very easy to construct mutually-contradictory link specifica‐
tions, or specifications that can never be matched. The program does
not check for these conditions.
Jul 15, 2002 DEVLINKS(1M)
