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 . 166The latter 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 in octal. 206.It Cm user Ar uid 207Set the UID to 208.Ar uid , 209which may be a user name 210(looked up in 211.Pa /etc/passwd ) 212or number. 213.It Cm unhide 214Unhide the node. 215.El 216.Sh IMPLEMENTATION NOTES 217Rulesets are created by the kernel at the first reference, 218and destroyed when the last reference disappears. 219E.g., a ruleset is created when a rule is added to it or when it is set 220as the current ruleset for a mount-point; 221a ruleset is destroyed when the last rule in it is deleted, 222and no other references to it exist 223(i.e., it is not included by any rules, and it is not the current ruleset 224for any mount-point). 225.Pp 226Ruleset number 0 is the default ruleset for all new mount-points. 227It is always empty, cannot be modified or deleted, and does not show up 228in the output of 229.Cm showsets . 230.Pp 231Rules and rulesets are unique to the entire system, 232not a particular mount-point. 233I.e., a 234.Cm showsets 235will return the same information regardless of the mount-point specified with 236.Fl m . 237The mount-point is only relevant when changing what its current ruleset is, 238or when using one of the apply commands. 239.Sh EXAMPLES 240When the system boots, 241the only ruleset that exists is ruleset number 0; 242since the latter may not be modified, we have to create another ruleset 243before adding rules. 244Note that since most of the following examples do not specify 245.Fl m , 246the operations are performed on 247.Pa /dev 248(this only matters for things that might change the properties of nodes). 249.Pp 250.Dl "devfs ruleset 10" 251.Pp 252Specify that ruleset 10 should be the current ruleset for 253.Pa /dev 254(if it does not already exist, it is created). 255.Pp 256.Dl "devfs rule add path speaker mode 666" 257.Pp 258Add a rule that causes all nodes that have a path that matches 259.Dq Li speaker 260(this is only 261.Pa /dev/speaker ) 262to have the file mode 666 (read and write for all). 263Note that if any such nodes already exist, their mode will not be changed 264unless this rule (or ruleset) is explicitly applied (see below). 265The mode 266.Em will 267be changed if the node is created 268.Em after 269the rule is added 270(e.g., the 271.Pa atspeaker 272module is loaded after the above rule is added). 273.Pp 274.Dl "devfs rule applyset" 275.Pp 276Apply all the rules in the current ruleset to all the existing nodes. 277E.g., if the above rule was added after 278.Pa /dev/speaker 279was created, 280this command will cause its file mode to be changed to 666, 281as rule prescribes. 282.Pp 283.Dl devfs rule add path "snp*" mode 660 group snoopers 284.Pp 285(Quoting the argument to 286.Cm path 287is often necessary to disable the shell's globbing features.) 288For all devices with a path that matches 289.Dq Li snp* , 290set the file more to 660, and the GID to 291.Dq Li snoopers . 292This permits users in the 293.Dq Li snoopers 294group to use the 295.Xr snp 4 296devices. 297.Pp 298.Dl "devfs rule -s 20 add major 53 group games" 299.Pp 300Add a rule to ruleset number 20. 301Since this ruleset is not the current ruleset for any mount-points, 302this rule is never applied automatically (unless ruleset 20 becomes 303a current ruleset for some mount-point at a later time). 304However, it can be applied explicitly, as such: 305.Pp 306.Dl "devfs -m /my/jail/dev rule -s 20 applyset" 307.Pp 308This will apply all rules in ruleset number 20 to the DEVFS mount on 309.Pa /my/jail/dev . 310It does not matter that ruleset 20 is not the current ruleset for that 311mount-point; the rules are applied regardless. 312.Pp 313.Dl "devfs rule apply hide" 314.Pp 315Since this rule has no conditions, the action 316.Pq Cm hide 317will be applied to all nodes. 318Since hiding all nodes is not very useful, we can undo like so: 319.Pp 320.Dl "devfs rule apply unhide" 321.Pp 322which applies 323.Cm unhide 324to all the nodes, 325causing them to reappear. 326.Pp 327.Dl "cat my_rules | devfs rule -s 10 add -" 328.Pp 329Add all the rules from the file 330.Pa my_rules 331to ruleset 10. 332.Pp 333.Dl "devfs rule -s 20 show | devfs rule -s 10 add -" 334.Pp 335Since 336.Cm show 337outputs valid rules, 338this feature can be used to copy rulesets. 339The above copies all the rules from ruleset 20 into ruleset 10. 340The rule numbers are preserved, 341but ruleset 10 may already have rules with non-conflicting numbers 342(these will be preserved). 343.Sh SEE ALSO 344.Xr chmod 1 , 345.Xr jail 2 , 346.Xr glob 3 , 347.Xr devfs 5 , 348.Xr chown 8 , 349.Xr jail 8 , 350.Xr mknod 8 351.Sh AUTHORS 352.An Dima Dorfman 353