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.Ss 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. 146If the first token of a rule specification is a single dash 147.Pq Dq - , 148rules are read from the standard input and the rest of the specification 149is ignored. 150.Pp 151The following conditions are recognized. 152Conditions are ANDed together when matching a device; 153if OR is desired, multiple rules can be written. 154.Bl -tag -offset indent 155.It Cm major Ar majdev 156Matches any node with a major number equal to 157.Ar majdev . 158.It Cm path Ar pattern 159Matches any node with a path that matches 160.Ar pattern . 161The latter is interpreted as a 162.Xr glob 3 Ns -style 163pattern. 164(Note: Pattern matching is currently unimplemented; 165the only wildcard recognized is an asterisk at the end of the string. 166This will be corrected in the future.) 167.It Cm type Ar devtype 168Matches any node that is of type 169.Ar devtype . 170Valid types are 171.Li disk , mem , tape 172and 173.Li tty . 174.El 175.Pp 176The following actions are recognized. 177Although there is no explicit delimiter between conditions and actions, 178they may not be intermixed. 179.Bl -tag -offset indent 180.It Cm group Ar gid 181Set the GID of the node to 182.Ar gid , 183which may be a group name 184(looked up in 185.Pa /etc/group ) 186or number. 187.It Cm hide 188Hide the node. 189Nodes may later be revived manually with 190.Xr mknod 8 , 191or with the 192.Cm unhide 193action. 194.It Cm include Ar ruleset 195Apply all the rules in ruleset number 196.Ar ruleset 197to the node. 198This does not necessarily result in any changes to the node 199(e.g., if none of the rules in the included ruleset match). 200.It Cm mode Ar filemode 201Set the file mode to 202.Ar filemode , 203which is interpreted in octal. 204.It Cm user Ar uid 205Set the UID to 206.Ar uid , 207which may be a user name 208(looked up in 209.Pa /etc/passwd ) 210or number. 211.It Cm unhide 212Unhide the node. 213.El 214.Sh IMPLEMENTATION NOTES 215Rulesets are created by the kernel at the first reference, 216and destroyed when the last reference disappears. 217E.g., a ruleset is created when a rule is added to it or when it is set 218as the current ruleset for a mount-point; 219a ruleset is destroyed when the last rule in it is deleted, 220and no other references to it exist 221(i.e., it is not included by any rules, and it is not the current ruleset 222for any mount-point). 223.Pp 224Ruleset number 0 is the default ruleset for all new mount-points. 225It is always empty, cannot be modified or deleted, and does not show up 226in the output of 227.Cm showsets . 228.Pp 229Rules and rulesets are unique to the entire system, 230not a particular mount-point. 231I.e., a 232.Cm showsets 233will return the same information regardless of the mount-point specified with 234.Fl m . 235The mount-point is only relevant when changing what its current ruleset is, 236or when using one of the apply commands. 237.Sh EXAMPLES 238When the system boots, 239the only ruleset that exists is ruleset number 0; 240since the latter may not be modified, we have to create another ruleset 241before adding rules. 242Note that since most of the following examples don't specify 243.Fl m , 244the operations are performed on 245.Pa /dev 246(this only matters for things that might change the properties of nodes). 247.Pp 248.Dl devfs ruleset 10 249.Pp 250Specify that ruleset 10 should be the current ruleset for 251.Pa /dev 252(if it does not already exist, it is created). 253.Pp 254.Dl devfs rule add path speaker mode 666 255.Pp 256Add a rule that causes all nodes that have a path that matches 257"speaker" 258(this is only 259.Pa /dev/speaker ) 260to have the file mode 666 (read and write for all). 261Note that if any such nodes already exist, their mode will not be changed 262unless this rule (or ruleset) is explicitly applied (see below). 263The mode 264.Em will 265be changed if the node is created 266.Em after 267the rule is added 268(e.g., the 269.Pa atspeaker 270module is loaded after the above rule is added). 271.Pp 272.Dl devfs rule applyset 273.Pp 274Apply all the rules in the current ruleset to all the existing nodes. 275E.g., if the above rule was added after 276.Pa /dev/speaker 277was created, 278this command will cause its file mode to be changed to 666, 279as rule rule prescribes. 280.Pp 281.Dl devfs rule add path "snp*" mode 660 group snoopers 282.Pp 283(Quoting the argument to 284.Cm path 285is often necessary to disable the shell's globbing features.) 286For all devices with a path that matches "snp*", 287set the file more to 660, and the GID to 288.Li snoopers . 289This permits users in the 290.Li snoopers 291group to use the 292.Xr snp 4 293devices. 294.Pp 295.Dl devfs rule -s 20 add major 53 group games 296.Pp 297Add a rule to ruleset number 20. 298Since this ruleset is not the current ruleset for any mount-points, 299this rule is never applied automatically (unless ruleset 20 becomes 300a current ruleset for some mount-point at a later time). 301However, it can be applied explicitly, as such: 302.Pp 303.Dl devfs -m /my/jail/dev rule -s 20 applyset 304.Pp 305This will apply all rules in ruleset number 20 to the DEVFS mount on 306.Pa /my/jail/dev . 307It doesn't matter that ruleset 20 is not the current ruleset for that 308mount-point; the rules are applied regardless. 309.Pp 310.Dl devfs rule apply hide 311.Pp 312Since this rule has no conditions, the action 313.Pq Cm hide 314will be applied to all nodes. 315Since hiding all nodes isn't very useful, we can undo like so: 316.Pp 317.Dl devfs rule apply unhide 318.Pp 319which applies 320.Cm unhide 321to all the nodes, 322causing them to reappear. 323.Pp 324.Dl cat my_rules | devfs rule -s 10 add - 325.Pp 326Add all the rules from the file 327.Pa my_rules 328to ruleset 10. 329.Pp 330.Dl devfs rule -s 20 show | devfs rule -s 10 add - 331.Pp 332Since 333.Cm show 334outputs valid rules, 335this feature can be used to copy rulesets. 336The above copies all the rules from ruleset 20 into ruleset 10. 337The rule numbers are preserved, 338but ruleset 10 may already have rules with non-conflicting numbers 339(these will be preserved). 340.Sh SEE ALSO 341.Xr jail 2 , 342.Xr glob 3 , 343.Xr devfs 5 , 344.Xr chmod 8 , 345.Xr chown 8 , 346.Xr jail 8 , 347.Xr mknod 8 348.Sh AUTHORS 349.An Dima Dorfman 350