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.Dt DEVFS 8 29.Dd July 1, 2002 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.Cm 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 first keyword after the program name determines the context for 47the rest of the arguments. 48For example, 49most of the commands related to the rule subsystem must be preceded by the 50.Cm rule 51keyword. 52The following flags are common to all keywords: 53.Bl -tag -offset indent 54.It Fl m Ar mount-point 55Operate on 56.Ar mount-point , 57which is expected to be a 58.Xr devfs 5 59mount. 60If this option is not specified, 61.Nm 62operates on 63.Pa /dev . 64.El 65.Sh RULE SUBSYSTEM 66The 67.Xr devfs 5 68rule subsystem provides a way for the administrator of a system to control 69the attributes of DEVFS nodes. 70.\" XXX devfs node? entry? what? 71Each DEVFS mount-point has a 72.Dq ruleset , 73or a list of rules, 74associated with it. 75When a device driver creates a new node, 76all the rules in the ruleset associated with each mount-point are applied 77(see below) before the node becomes visible to the userland. 78This permits the administrator to change the properties, 79including the visibility, 80of certain nodes. 81For example, one might want to hide all disk nodes in a 82.Xr jail 2 Ns 's 83.Pa /dev . 84.Ss Rule Manipulation 85Rule manipulation commands follow the 86.Cm rule 87keyword. 88The following flags are common to all of the rule manipulation commands: 89.Bl -tag -offset indent 90.It Fl s Ar ruleset 91Operate on the ruleset with the number 92.Ar ruleset . 93If this is not specified, 94the commands operate on the ruleset currently associated with the 95specified mount-point. 96.El 97.Pp 98The following commands are recognized: 99.Bl -tag -offset indent 100.It Cm rule add Oo Ar rulenum Oc Ar rulespec 101Add the rule described by 102.Ar rulespec 103(defined below) 104to the ruleset. 105The rule has the number 106.Ar rulenum 107if it is explicitly specified; 108otherwise, the rule number is automatically determined by the kernel. 109.It Cm rule apply Ar rulenum | Ar rulespec 110Apply rule number 111.Ar rulenum 112or the rule described by 113.Ar rulespec 114to the mount-point. 115Rules that are "applied" have their conditions checked against all nodes 116in the mount-point, and the actions taken if they match. 117.It Cm rule applyset 118Apply all the rules in the ruleset to the mount-point 119(see above for the definition of "apply"). 120.It Cm rule del Ar rulenum 121Delete rule number 122.Ar rulenum 123from the ruleset. 124.It Cm rule delset 125Delete all rules from the ruleset. 126.It Cm rule show Op Ar rulenum 127Display the rule number 128.Ar rulenum , 129or all the rules in the ruleset. 130The output lines (one line per rule) are expected to be valid 131.Ar rulespec Ns s . 132.It Cm rule showsets 133Report the numbers of existing rulesets. 134.It Cm ruleset Ar ruleset 135Set ruleset number 136.Ar ruleset 137as the current ruleset for the mount-point. 138.El 139.Ss Rule Specification 140Rules have two parts: the conditions and the actions. 141The conditions determine which DEVFS nodes the rule matches, 142and the actions determine what should be done when a rule matches a node. 143For example, a rule can be written that sets the GID to 144.Li games 145for all devices with major number 53. 146.Pp 147The following conditions are recognized. 148Conditions are ANDed together when matching a device; 149if OR is desired, multiple rules can be written. 150.Bl -tag -offset indent 151.It Cm major Ar majdev 152Matches any node with a major number equal to 153.Ar majdev . 154.It Cm path Ar pattern 155Matches any node with a path that matches 156.Ar pattern . 157The latter is interpreted as a 158.Xr glob 3 Ns -style 159pattern. 160(Note: Pattern matching is currently unimplemented; 161the only wildcard recognized is an asterisk at the end of the string. 162This will be corrected in the future.) 163.It Cm type Ar devtype 164Matches any node that is of type 165.Ar devtype . 166Valid types are 167.Li disk , mem , tape 168and 169.Li tty . 170.El 171.Pp 172The following actions are recognized. 173Although there is no explicit delimiter between conditions and actions, 174they may not be intermixed. 175.Bl -tag -offset indent 176.It Cm group Ar gid 177Set the GID of the node to 178.Ar gid , 179which may be a group name 180(looked up in 181.Pa /etc/group ) 182or number. 183.It Cm hide 184Hide the node. 185Nodes may later be revived manually with 186.Xr mknod 8 , 187or with the 188.Cm unhide 189action. 190.It Cm include Ar ruleset 191Apply all the rules in ruleset number 192.Ar ruleset 193to the node. 194This does not necessarily result in any changes to the node 195(e.g., if none of the rules in the included ruleset match). 196.It Cm mode Ar filemode 197Set the file mode to 198.Ar filemode , 199which is interpreted in octal. 200.It Cm user Ar uid 201Set the UID to 202.Ar uid , 203which may be a user name 204(looked up in 205.Pa /etc/passwd ) 206or number. 207.It Cm unhide 208Unhide the node. 209.El 210.Ss Notes 211.Bl -bullet -offset indent 212.It 213Rulesets are created by the kernel at the first reference, 214and destroyed when the last reference disappears. 215E.g., a ruleset is created when a rule is added to it or when it is set 216as the current ruleset for a mount-point; 217a ruleset is destroyed when the last rule in it is deleted, 218and no other references to it exist 219(i.e., it is not included by any rules, and it is not the current ruleset 220for any mount-point). 221.It 222Ruleset number 0 is the default ruleset for all new mount-points. 223It is always empty, cannot be modified or deleted, and does not show up 224in the output of 225.Cm showsets . 226.It 227Rules and rulesets are unique to the entire system, 228not a particular mount-point. 229I.e., a 230.Cm showsets 231will return the same information regardless of the mount-point specified with 232.Fl m . 233The mount-point is only relevant when changing what its current ruleset is, 234or when using one of the apply commands. 235.El 236.Ss Examples 237When the system boots, 238the only ruleset that exists is ruleset number 0; 239since the latter may not be modified, we have to create another ruleset 240before adding rules. 241Note that since most of the following examples don't specify 242.Fl m , 243the operations are performed on 244.Pa /dev 245(this only matters for things that might change the properties of nodes). 246.Pp 247.Dl devfs ruleset 10 248.Pp 249Specify that ruleset 10 should be the current ruleset for 250.Pa /dev 251(if it does not already exist, it is created). 252.Pp 253.Dl devfs rule add path speaker mode 666 254.Pp 255Add a rule that causes all nodes that have a path that matches 256"speaker" 257(this is only 258.Pa /dev/speaker ) 259to have the file mode 666 (read and write for all). 260Note that if any such nodes already exist, their mode will not be changed 261unless this rule (or ruleset) is explicitly applied (see below). 262The mode 263.Em will 264be changed if the node is created 265.Em after 266the rule is added 267(e.g., the 268.Pa atspeaker 269module is loaded after the above rule is added). 270.Pp 271.Dl devfs rule applyset 272.Pp 273Apply all the rules in the current ruleset to all the existing nodes. 274E.g., if the above rule was added after 275.Pa /dev/speaker 276was created, 277this command will cause its file mode to be changed to 666, 278as rule rule prescribes. 279.Pp 280.Dl devfs rule add path "snp*" mode 660 group snoopers 281.Pp 282(Quoting the argument to 283.Cm path 284is often necessary to disable the shell's globbing features.) 285For all devices with a path that matches "snp*", 286set the file more to 660, and the GID to 287.Li snoopers . 288This permits users in the 289.Li snoopers 290group to use the 291.Xr snp 4 292devices. 293.Pp 294.Dl devfs rule -s 20 add major 53 group games 295.Pp 296Add a rule to ruleset number 20. 297Since this ruleset is not the current ruleset for any mount-points, 298this rule is never applied automatically (unless ruleset 20 becomes 299a current ruleset for some mount-point at a later time). 300However, it can be applied explicitly, as such: 301.Pp 302.Dl devfs -m /my/jail/dev rule -s 20 applyset 303.Pp 304This will apply all rules in ruleset number 20 to the DEVFS mount on 305.Pa /my/jail/dev . 306It doesn't matter that ruleset 20 is not the current ruleset for that 307mount-point; the rules are applied regardless. 308.Pp 309.Dl devfs rule apply hide 310.Pp 311Since this rule has no conditions, the action 312.Pq Cm hide 313will be applied to all nodes. 314Since hiding all nodes isn't very useful, we can undo like so: 315.Pp 316.Dl devfs rule apply unhide 317.Sh SEE ALSO 318.Xr jail 2 , 319.Xr glob 3 , 320.Xr devfs 5 , 321.Xr chmod 8 , 322.Xr chown 8 , 323.Xr jail 8 , 324.Xr mknod 8 325.Sh AUTHORS 326.An Dima Dorfman 327