1.\" 2.\" Copyright (c) 2002 Dima Dorfman. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd July 1, 2002 29.Dt DEVFS 8 30.Os 31.Sh NAME 32.Nm devfs 33.Nd "DEVFS control" 34.Sh SYNOPSIS 35.Nm 36.Op Fl m Ar mount-point 37.Ar keyword 38.Ar argument ... 39.Sh DESCRIPTION 40The 41.Nm 42utility provides an interface to manipulate properties of 43.Xr devfs 5 44mounts. 45.Pp 46The 47.Ar keyword 48argument determines the context for 49the rest of the arguments. 50For example, 51most of the commands related to the rule subsystem must be preceded by the 52.Cm rule 53keyword. 54The following flags are common to all keywords: 55.Bl -tag -offset indent 56.It Fl m Ar mount-point 57Operate on 58.Ar mount-point , 59which is expected to be a 60.Xr devfs 5 61mount. 62If this option is not specified, 63.Nm 64operates on 65.Pa /dev . 66.El 67.Ss Rule Subsystem 68The 69.Xr devfs 5 70rule subsystem provides a way for the administrator of a system to control 71the attributes of DEVFS nodes. 72.\" XXX devfs node? entry? what? 73Each DEVFS mount-point has a 74.Dq ruleset , 75or a list of rules, 76associated with it. 77When a device driver creates a new node, 78all the rules in the ruleset associated with each mount-point are applied 79(see below) before the node becomes visible to the userland. 80This permits the administrator to change the properties, 81including the visibility, 82of certain nodes. 83For example, one might want to hide all disk nodes in a 84.Xr jail 2 Ns 's 85.Pa /dev . 86.Ss Rule Manipulation 87Rule manipulation commands follow the 88.Cm rule 89keyword. 90The following flags are common to all of the rule manipulation commands: 91.Bl -tag -offset indent 92.It Fl s Ar ruleset 93Operate on the ruleset with the number 94.Ar ruleset . 95If this is not specified, 96the commands operate on the ruleset currently associated with the 97specified mount-point. 98.El 99.Pp 100The following commands are recognized: 101.Bl -tag -offset indent 102.It Cm rule add Oo Ar rulenum Oc Ar rulespec 103Add the rule described by 104.Ar rulespec 105(defined below) 106to the ruleset. 107The rule has the number 108.Ar rulenum 109if it is explicitly specified; 110otherwise, the rule number is automatically determined by the kernel. 111.It Cm rule apply Ar rulenum | rulespec 112Apply rule number 113.Ar rulenum 114or the rule described by 115.Ar rulespec 116to the mount-point. 117Rules that are 118.Dq applied 119have their conditions checked against all nodes 120in the mount-point and the actions taken if they match. 121.It Cm rule applyset 122Apply all the rules in the ruleset to the mount-point 123(see above for the definition of 124.Dq apply ) . 125.It Cm rule del Ar rulenum 126Delete rule number 127.Ar rulenum 128from the ruleset. 129.It Cm rule delset 130Delete all rules from the ruleset. 131.It Cm rule show Op Ar rulenum 132Display the rule number 133.Ar rulenum , 134or all the rules in the ruleset. 135The output lines (one line per rule) are expected to be valid 136.Ar rulespec Ns s . 137.It Cm rule showsets 138Report the numbers of existing rulesets. 139.It Cm ruleset Ar ruleset 140Set ruleset number 141.Ar ruleset 142as the current ruleset for the mount-point. 143.El 144.Ss Rule Specification 145Rules have two parts: the conditions and the actions. 146The conditions determine which DEVFS nodes the rule matches 147and the actions determine what should be done when a rule matches a node. 148For example, a rule can be written that sets the GID to 149.Dq Li games 150for all devices with major number 53. 151If the first token of a rule specification is a single dash 152.Pq Sq Fl , 153rules are read from the standard input and the rest of the specification 154is ignored. 155.Pp 156The following conditions are recognized. 157Conditions are ANDed together when matching a device; 158if OR is desired, multiple rules can be written. 159.Bl -tag -offset indent 160.It Cm major Ar majdev 161Matches any node with a major number equal to 162.Ar majdev . 163.It Cm path Ar pattern 164Matches any node with a path that matches 165.Ar pattern , 166which is interpreted as a 167.Xr glob 3 Ns -style 168pattern. 169.It Cm type Ar devtype 170Matches any node that is of type 171.Ar devtype . 172Valid types are 173.Cm disk , mem , tape 174and 175.Cm tty . 176.El 177.Pp 178The following actions are recognized. 179Although there is no explicit delimiter between conditions and actions, 180they may not be intermixed. 181.Bl -tag -offset indent 182.It Cm group Ar gid 183Set the GID of the node to 184.Ar gid , 185which may be a group name 186(looked up in 187.Pa /etc/group ) 188or number. 189.It Cm hide 190Hide the node. 191Nodes may later be revived manually with 192.Xr mknod 8 193or with the 194.Cm unhide 195action. 196.It Cm include Ar ruleset 197Apply all the rules in ruleset number 198.Ar ruleset 199to the node. 200This does not necessarily result in any changes to the node 201(e.g., if none of the rules in the included ruleset match). 202.It Cm mode Ar filemode 203Set the file mode to 204.Ar filemode , 205which is interpreted as in 206.Xr chmod 1 . 207.It Cm user Ar uid 208Set the UID to 209.Ar uid , 210which may be a user name 211(looked up in 212.Pa /etc/passwd ) 213or number. 214.It Cm unhide 215Unhide the node. 216.El 217.Sh IMPLEMENTATION NOTES 218Rulesets are created by the kernel at the first reference 219and destroyed when the last reference disappears. 220E.g., a ruleset is created when a rule is added to it or when it is set 221as the current ruleset for a mount-point, and 222a ruleset is destroyed when the last rule in it is deleted 223and no other references to it exist 224(i.e., it is not included by any rules and it is not the current ruleset 225for any mount-point). 226.Pp 227Ruleset number 0 is the default ruleset for all new mount-points. 228It is always empty, cannot be modified or deleted, and does not show up 229in the output of 230.Cm showsets . 231.Pp 232Rules and rulesets are unique to the entire system, 233not a particular mount-point. 234I.e., a 235.Cm showsets 236will return the same information regardless of the mount-point specified with 237.Fl m . 238The mount-point is only relevant when changing what its current ruleset is 239or when using one of the apply commands. 240.Sh EXAMPLES 241When the system boots, 242the only ruleset that exists is ruleset number 0; 243since the latter may not be modified, we have to create another ruleset 244before adding rules. 245Note that since most of the following examples do not specify 246.Fl m , 247the operations are performed on 248.Pa /dev 249(this only matters for things that might change the properties of nodes). 250.Pp 251.Dl "devfs ruleset 10" 252.Pp 253Specify that ruleset 10 should be the current ruleset for 254.Pa /dev 255(if it does not already exist, it is created). 256.Pp 257.Dl "devfs rule add path speaker mode 666" 258.Pp 259Add a rule that causes all nodes that have a path that matches 260.Dq Li speaker 261(this is only 262.Pa /dev/speaker ) 263to have the file mode 666 (read and write for all). 264Note that if any such nodes already exist, their mode will not be changed 265unless this rule (or ruleset) is explicitly applied (see below). 266The mode 267.Em will 268be changed if the node is created 269.Em after 270the rule is added 271(e.g., the 272.Pa atspeaker 273module is loaded after the above rule is added). 274.Pp 275.Dl "devfs rule applyset" 276.Pp 277Apply all the rules in the current ruleset to all the existing nodes. 278E.g., if the above rule was added after 279.Pa /dev/speaker 280was created, 281this command will cause its file mode to be changed to 666 282as prescribed by the rule. 283.Pp 284.Dl devfs rule add path "snp*" mode 660 group snoopers 285.Pp 286(Quoting the argument to 287.Cm path 288is often necessary to disable the shell's globbing features.) 289For all devices with a path that matches 290.Dq Li snp* , 291set the file more to 660 and the GID to 292.Dq Li snoopers . 293This permits users in the 294.Dq Li snoopers 295group to use the 296.Xr snp 4 297devices. 298.Pp 299.Dl "devfs rule -s 20 add major 53 group games" 300.Pp 301Add a rule to ruleset number 20. 302Since this ruleset is not the current ruleset for any mount-points, 303this rule is never applied automatically (unless ruleset 20 becomes 304a current ruleset for some mount-point at a later time). 305However, it can be applied explicitly, as such: 306.Pp 307.Dl "devfs -m /my/jail/dev rule -s 20 applyset" 308.Pp 309This will apply all rules in ruleset number 20 to the DEVFS mount on 310.Pa /my/jail/dev . 311It does not matter that ruleset 20 is not the current ruleset for that 312mount-point; the rules are still applied. 313.Pp 314.Dl "devfs rule apply hide" 315.Pp 316Since this rule has no conditions, the action 317.Pq Cm hide 318will be applied to all nodes. 319Since hiding all nodes is not very useful, we can undo it: 320.Pp 321.Dl "devfs rule apply unhide" 322.Pp 323which applies 324.Cm unhide 325to all the nodes, 326causing them to reappear. 327.Pp 328.Dl "devfs rule -s 10 add - < my_rules" 329.Pp 330Add all the rules from the file 331.Pa my_rules 332to ruleset 10. 333.Pp 334.Dl "devfs rule -s 20 show | devfs rule -s 10 add -" 335.Pp 336Since 337.Cm show 338outputs valid rules, 339this feature can be used to copy rulesets. 340The above copies all the rules from ruleset 20 into ruleset 10. 341The rule numbers are preserved, 342but ruleset 10 may already have rules with non-conflicting numbers 343(these will be preserved). 344.Sh SEE ALSO 345.Xr chmod 1 , 346.Xr jail 2 , 347.Xr glob 3 , 348.Xr devfs 5 , 349.Xr chown 8 , 350.Xr jail 8 , 351.Xr mknod 8 352.Sh AUTHORS 353.An Dima Dorfman 354