1.\" 2.\" Copyright (c) 2002 M. Warner Losh <imp@FreeBSD.org> 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. The name of the author may not be used to endorse or promote products 10.\" derived from this software without specific prior written permission. 11.\" 12.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 13.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 14.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 15.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 16.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 17.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 18.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 19.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 20.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 21.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 22.\" SUCH DAMAGE. 23.\" 24.\" $FreeBSD$ 25.\" 26.\" The section on comments was taken from named.conf.5, which has the 27.\" following copyright: 28.\" Copyright (c) 1999-2000 by Internet Software Consortium 29.\" 30.\" Permission to use, copy, modify, and distribute this software for any 31.\" purpose with or without fee is hereby granted, provided that the above 32.\" copyright notice and this permission notice appear in all copies. 33.\" 34.\" THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS 35.\" ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 36.\" OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 37.\" CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 38.\" DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 39.\" PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 40.\" ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 41.\" SOFTWARE. 42.\" 43.Dd December 1, 2022 44.Dt DEVD.CONF 5 45.Os 46.Sh NAME 47.Nm devd.conf 48.Nd configuration file for 49.Xr devd 8 50.Sh DESCRIPTION 51.Ss General Syntax 52A 53.Xr devd 8 54configuration consists of two general features, statements 55and comments. 56All statements end with a semicolon. 57Many statements can contain substatements, which are also 58terminated with a semicolon. 59.Pp 60The following statements are supported: 61.Bl -tag -width ".Ic options" 62.It Ic attach 63Specifies various matching criteria and actions to perform when 64a newly attached device matches said criteria. 65.It Ic detach 66Specifies various matching criteria and actions to perform when 67a newly detached device matches said criteria. 68.It Ic nomatch 69Specifies various matching criteria and actions to perform when 70no device driver currently loaded in the kernel claims a (new) 71device. 72.It Ic notify 73Specifies various matching criteria and actions to perform when the kernel 74sends an event notification to userland. 75.It Ic options 76Specifies various options and parameters for the operation of 77.Xr devd 8 . 78.El 79.Pp 80Statements may occur in any order in the configuration file, and may be 81repeated as often as required. 82Further details on the syntax and meaning of each statement and their 83substatements are explained below. 84.Pp 85Each statement, except 86.Ic options 87has a priority (an arbitrary number) associated with it, where 88.Ql 0 89is defined as the lowest priority. 90If two statements match the same event, only the action of the statement with 91highest priority will be executed. 92In this way generic statements can be overridden for devices or 93notifications that require special attention. 94.Pp 95The general syntax of a statement is: 96.Bd -literal -offset indent 97statement priority { 98 substatement "value"; 99 ... 100 substatement "value"; 101}; 102.Ed 103.Ss Sub-statements 104The following sub-statements are supported within the 105.Ic options 106statement. 107.Bl -tag -width ".Ic directory" 108.It Ic directory Qq Ar /some/path ; 109Adds the given directory to the list of directories from which 110.Xr devd 8 111will read all files named "*.conf" as further 112configuration files. 113Any number of 114.Ic directory 115statements can be used. 116.It Ic pid-file Qq Pa /var/run/devd.pid ; 117Specifies PID file. 118.It Ic set Ar regexp-name Qq Ar (some|regexp) ; 119Creates a regular expression and assigns it to the variable 120.Ar regexp-name . 121The variable is available throughout the rest of 122the configuration file. 123If the string begins with 124.Ql \&! , 125it matches if the regular expression formed by the rest of the string 126does not match. 127All regular expressions have an implicit 128.Ql ^$ 129around them. 130.El 131.Pp 132The following sub-statements are supported within the 133.Ic attach 134and 135.Ic detach 136statements. 137.Bl -tag -width ".Ic directory" 138.It Ic action Qq Ar command ; 139Command to execute upon a successful match. 140Example 141.Dq Li "/etc/pccard_ether $device-name start" . 142.It Ic class Qq Ar string ; 143This is shorthand for 144.Dq Ic match Qo Li class Qc Qq Ar string . 145.It Ic device-name Qq string ; 146This is shorthand for 147.Dq Ic match Qo Li device-name Qc Qq Ar string . 148This matches a device named 149.Ar string , 150which is allowed to be a regular expression or a variable previously created 151containing a regular expression. 152The 153.Dq Li device-name 154variable 155is available for later use with the 156.Ic action 157statement. 158.It Ic match Qo Ar variable Qc Qq Ar value ; 159Matches the content of 160.Ar value 161against 162.Ar variable ; 163the content of 164.Ar value 165may be a regular expression. 166Not required during 167.Ic attach 168nor 169.Ic detach 170events since the 171.Ic device-name 172statement takes care of all device matching. 173For a partial list of variables, see below. 174.It Ic media-type Qq Ar string ; 175For network devices, 176.Ic media-type 177will match devices that have the given media type. 178Valid media types are: 179.Dq Li Ethernet , 180.Dq Li 802.11 , 181and 182.Dq Li ATM . 183.It Ic subdevice Qq Ar string ; 184This is shorthand for 185.Dq Ic match Qo Li subdevice Qc Qq Ar string . 186.El 187.Pp 188The following sub-statements are supported within the 189.Ic nomatch 190statement. 191.Bl -tag -width ".Ic directory" 192.It Ic action Qq Ar command ; 193Same as above. 194.It Ic match Qo Ar variable Qc Qq Ar value ; 195Matches the content of 196.Ar value 197against 198.Ar variable ; 199the content of 200.Ar value 201may be a regular expression. 202For a partial list of variables, see below. 203.El 204.Pp 205The following sub-statements are supported within the 206.Ic notify 207statement. 208The 209.Dq Li notify 210variable is available inside this statement and contains, a value, depending 211on which system and subsystem that delivered the event. 212.Bl -tag -width ".Ic directory" 213.It Ic action Qq Ar command ; 214Command to execute upon a successful match. 215Example 216.Dq Li "/etc/rc.d/power_profile $notify" . 217.It Ic match Qo Ar system | subsystem | type | notify Qc Qq Ar value ; 218Any number of 219.Ic match 220statements can exist within a 221.Ic notify 222statement; 223.Ar value 224can be either a fixed string or a regular expression. 225Below is a list of available systems, subsystems, and types. 226.It Ic media-type Qq Ar string ; 227See above. 228.El 229.Ss Variables that can be used with the match statement 230A partial list of variables and their possible values that can be used together 231with the 232.Ic match 233statement. 234The variables are published by the bus based on characteristics of the device 235that generated the event (for device events). 236Variables for other classes of events are dependent on those events. 237.Pp 238.Bl -tag -width ".Li manufacturer" -compact 239.It Ic Variable 240.Ic Description 241.It Li * 242The entire message from the current event. 243.It Li _ 244The entire message from the current event, after the initial type character. 245.It Li timestamp 246The time this event was processed, in seconds since 1970 dot fraction. 247.It Li bus 248Device name of parent bus. 249.It Li cdev 250Device node path if one is created by the 251.Xr devfs 5 252filesystem. 253.It Li class 254Device class. 255.It Li comm 256Executable name (kernel). 257.It Li core 258Path to core file (kernel). 259.It Li device 260Device ID. 261.It Li devclass 262Device Class (USB). 263.It Li devsubclass 264Device Sub-class (USB). 265.It Li device-name 266Name of attached/detached device. 267.It Li endpoints 268Endpoint count (USB). 269.It Li function 270Card functions. 271.It Li interface 272Interface ID (USB). 273.It Li intclass 274Interface Class (USB). 275.It Li intprotocol 276Interface Protocol (USB). 277.It Li intsubclass 278Interface Sub-class (USB). 279.It Li jail 280Jail name for the process triggering the rule (RCTL). 281.It Li mode 282Peripheral mode (USB). 283.It Li notify 284Match the value of the 285.Dq Li notify 286variable. 287.It Li parent 288Parent device. 289.It Li pid 290PID of the process triggering the rule (RCTL). 291.It Li port 292Hub port number (USB). 293.It Li product 294Product ID (USB). 295.It Li release 296Hardware revision (USB). 297.It Li ruid 298Real UID of the process triggering the rule (RCTL). 299.It Li rule 300Rule (RCTL). 301.It Li sernum 302Serial Number (USB). 303.It Li slot 304Card slot. 305.It Li subvendor 306Sub-vendor ID (PCI). 307.It Li subdevice 308Sub-device ID (PCI). 309.It Li subsystem 310Matches a subsystem of a system, see below. 311.It Li system 312Matches a system type, see below. 313.It Li type 314Type of notification, see below. 315.It Li vendor 316Vendor ID. 317.El 318.Ss Notify matching 319A partial list of systems, subsystems, and types used within the 320.Ic notify 321mechanism. 322.\" 323.\" Please keep these tables sorted. Also, please use the same parameters 324.\" for each of the tables so that things line up in columns nicely. 325.\" Please do not omit the type column for notifiers that omit it. 326.Pp 327.Bl -column "System" "Subsystem" "1234567" -compact 328.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 329.It Li ACPI Ta Ta Ta 330Events related to the ACPI Subsystem. 331.It Li ACPI Ta Li ACAD Ta Ta 332AC line state ($notify=0x00 is offline, 0x01 is online). 333.It Li ACPI Ta Li Button Ta Ta 334Button state ($notify=0x00 is power, 0x01 is sleep). 335.It Li ACPI Ta Li CMBAT Ta Ta 336Battery events. 337.It Li ACPI Ta Li Dock Ta Ta 338Dock state ($notify=0x00 is undocked, 0x01 is docked). 339.It Li ACPI Ta Li Lid Ta Ta 340Lid state ($notify=0x00 is closed, 0x01 is open). 341.It Li ACPI Ta Li PROCESSOR Ta Ta 342Processor state/configuration ($notify=0x81 is a change in available Cx states). 343.It Li ACPI Ta Li Resume Ta Ta 344Resume notification. 345.It Li ACPI Ta Li Suspend Ta Ta 346Suspend notification. 347.It Li ACPI Ta Li Thermal Ta Ta 348Thermal zone events. 349.El 350.Pp 351.Bl -column "System" "Subsystem" "1234567" -compact 352.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 353.It Li AEON Ta Li power Ta Li press Ta 354The power button on an Amiga has been pressed. 355.El 356.Pp 357.Bl -column "System" "Subsystem" "1234567" -compact 358.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 359.It Li CAM Ta Ta Ta 360Events related to the 361.Xr cam 4 362system. 363.It Li CAM Ta Li periph Ta Ta 364Events related to peripheral devices. 365.It Li CAM Ta Li periph Ta Li error Ta 366Generic errors. 367.It Li CAM Ta Li periph Ta Li timeout Ta 368Command timeouts. 369.El 370.Pp 371.Bl -column "System" "Subsystem" "1234567" -compact 372.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 373.It Li CARP Ta Ta Ta 374Events related to the 375.Xr carp 4 376protocol. 377.It CARP Ta Ar vhid@inet Ta Ta 378The 379.Dq subsystem 380contains the actual CARP vhid and the name of the network interface 381on which the event took place. 382.It CARP Ta Ar vhid@inet Ta MASTER Ta 383Node become the master for a virtual host. 384.It CARP Ta Ar vhid@inet Ta BACKUP Ta 385Node become the backup for a virtual host. 386.El 387.Pp 388.Bl -column "System" "Subsystem" "1234567" -compact 389.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 390.It Li coretemp Ta Ta Ta 391Events related to the 392.Xr coretemp 4 393device. 394.It Li coretemp Ta Li Thermal Ta Ta 395Notification that the CPU core has reached critical temperature. 396.It Li coretemp Ta Li Thermal Ta Li temperature Ta 397String containing the temperature of the core that has become too hot. 398.El 399.Pp 400.Bl -column "System" "Subsystem" "1234567" -compact 401.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 402.It Li DEVFS 403.It Li DEVFS Ta Li CDEV Ta Li CREATE Ta 404The 405.Xr devfs 5 406node is created. 407.It Li DEVFS Ta Li CDEV Ta Li DESTROY Ta 408The 409.Xr devfs 5 410node is destroyed. 411.El 412.Pp 413.Bl -column "System" "Subsystem" "1234567" -compact 414.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 415.It Li ETHERNET Ta Ar inet Ta IFATTACH Ta 416Notification when the default VNET instance of the 417.Em inet 418interface is attached. 419.El 420.Pp 421.Bl -column "System" "Subsystem" "1234567" -compact 422.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 423.It Li GEOM Ta Ta Ta 424Events related to the 425.Xr geom 4 426framework. 427The difference compared to 428.Li DEVFS 429is that 430.Li GEOM 431only includes disk-like devices. 432.It Li GEOM Ta Li DEV Ta Li CREATE Ta 433A 434.Xr geom 4 435provider is created. 436.It Li GEOM Ta Li DEV Ta Li DESTROY Ta 437A 438.Xr geom 4 439provider is destroyed. 440.It Li GEOM Ta Li DEV Ta Li GEOM::physpath Ta 441The physical path of a device has changed. 442.It Li GEOM Ta Li DEV Ta Li GEOM::rotation_rate Ta 443The rotation rate of the disk has changed. 444.It Li GEOM Ta Li DEV Ta Li MEDIACHANGE Ta 445Physical media has changed. 446.It Li GEOM Ta Li DEV Ta Li SIZECHANGE Ta 447A 448.Xr geom 4 449provider size has changed. 450.El 451.Pp 452.Bl -column "System" "Subsystem" "1234567" -compact 453.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 454.It Li IFNET 455.It Li IFNET Ta Em inet Ta Ta 456The 457.Dq subsystem 458is the actual name of the network interface on which the event 459took place. 460.It Li IFNET Ta Em inet Ta Li LINK_UP Ta 461Carrier status changed to UP. 462.It Li IFNET Ta Em inet Ta Li LINK_DOWN Ta 463Carrier status changed to DOWN. 464.It Li IFNET Ta Em inet Ta Li ATTACH Ta 465The network interface is attached to the system. 466.It Li IFNET Ta Em inet Ta Li DETACH Ta 467The network interface is detached from the system. 468.It Li IFNET Ta Em inet Ta Li RENAME Ta 469The network interface is renamed. 470.It Li IFNET Ta Em inet Ta Li ADDR_ADD Ta 471The network interface address added. 472.It Li IFNET Ta Em inet Ta Li ADDR_DEL Ta 473The network interface address removed. 474.El 475.Pp 476.Bl -column "System" "Subsystem" "1234567" -compact 477.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 478.It Li kernel Ta Li signal Ta Li coredump Ta 479Notification that a process has crashed and dumped core. 480.It Li kernel Ta Li power Ta Li resume Ta 481Notification that the system has woken from the suspended state. 482.El 483.Pp 484.Bl -column "System" "Subsystem" "1234567" -compact 485.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 486.It Li PMU Ta Ta Ta 487Notification of events from various types of Power Management Units. 488.It Li PMU Ta Li "AC" Ta Ta 489Notifications of AC power related events. 490.It Li PMU Ta Li "AC" Ta Li overvoltage Ta 491An over-voltage condition was detected on the AC power line. 492.It Li PMU Ta Li "AC" Ta Li plugged Ta 493Power has been applied to the AC power line. 494.It Li PMU Ta Li "AC" Ta Li unplugged Ta 495Power has been removed from the AC power line. 496.It Li PMU Ta Li Battery Ta Ta 497.It Li PMU Ta Li Battery Ta absent Ta 498Battery is no longer absent. 499.It Li PMU Ta Li Battery Ta charged Ta 500The battery has become charged. 501.It Li PMU Ta Li Battery Ta charging Ta 502The battery has started charging. 503.It Li PMU Ta Li Battery Ta disconnected Ta 504The battery has been disconnected. 505.It Li PMU Ta Li Battery Ta high-temp Ta 506The battery reported a temperature over the limit. 507.It Li PMU Ta Li Battery Ta low-temp Ta 508The battery reported a temperature under the limit. 509.It Li PMU Ta Li Battery Ta plugged Ta 510The battery has become plugged (eg connected). 511.It Li PMU Ta Li Battery Ta shutdown-threshold Ta 512The power in the battery has fallen below the shutdown threshold. 513.It Li PMU Ta Li Battery Ta warning-threshold Ta 514The power in the battery has fallen below the warn the user threshold. 515.It Li PMU Ta Li Button Ta pressed Ta 516A button on a 517.Xr adb 4 518or 519.Xr pmu 4 520has been pressed. 521.It Li PMU Ta Li keys Ta Ta 522One of the keys on the 523.Xr adb 4 524keyboard has been pressed. 525.It Li PMU Ta Li keys Ta brightness Ta 526A brightness level change has been requested. 527Direction is in the $notify variable. 528.It Li PMU Ta Li keys Ta mute Ta 529The mute key 530.It Li PMU Ta Li keys Ta volume Ta 531A volume level change has been requested. 532Direction is in the $notify variable. 533.It Li PMU Ta Li keys Ta eject Ta 534An ejection has been requested. 535.It Li PMU Ta Li lid Ta close Ta 536The 537.Xr pmc 4 538device has detected the lid closing. 539.It Li PMU Ta Li lid Ta open Ta 540The 541.Xr pmc 4 542device has detected the lid openinging. 543.It Li PMU Ta Li POWER Ta ACLINE Ta 544The 545.Xr pmc 4 546device has deteted an AC line state ($notify=0x00 is offline, 0x01 is online). 547.It Li PMU Ta Li USB Ta overvoltage Ta 548An over-voltage condition on the power lines for the USB power pins. 549.It Li PMU Ta Li USB Ta plugged Ta 550A device has been plugged into a USB device. 551.It Li PMU Ta Li USB Ta undervoltage Ta 552An under-voltage condition on the power lines for the USB power pins. 553.It Li PMU Ta Li USB Ta unplugged Ta 554A device has been unplugged into a USB device. 555.El 556.Pp 557.Bl -column "System" "Subsystem" "1234567" -compact 558.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 559.It Li RCTL Ta Ta Ta 560Events related to the 561.Xr rctl 8 562framework. 563.It Li RCTL Ta Li rule Ta Li matched Ta 564A rule with action specified as "devctl" was triggered. 565.El 566.Pp 567.Bl -column "System" "Subsystem" "1234567" -compact 568.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 569.It Li USB Ta Ta Ta 570Events related to the USB subsystem. 571.It Li USB Ta Li DEVICE Ta Li ATTACH Ta 572USB device is attached to the system. 573.It Li USB Ta Li DEVICE Ta Li DETACH Ta 574USB device is detached to the system. 575.It Li USB Ta Li INTERFACE Ta Li ATTACH Ta 576USB interface is attached to a device. 577.It Li USB Ta Li INTERFACE Ta Li DETACH Ta 578USB interface is detached from a device. 579.El 580.Pp 581.Bl -column "System" "Subsystem" "1234567" -compact 582.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 583.It Li VFS Ta Ta Ta 584Events from the vfs system. 585.It Li VFS Ta Li FS Ta Ta 586Events that change what is mounted to the system. 587.It Li VFS Ta Li FS Ta Li MOUNT Ta 588Notification of a filesystem is mounted for the first time. 589.It Li VFS Ta Li FS Ta Li REMOUNT Ta 590Notification of a filesystem is remounted (whether or not the options actually change). 591.It Li VFS Ta Li FS Ta Li UNMOUNT Ta 592Notification of a filesystem being unmounted. 593.El 594.Pp 595.Bl -column "System" "Subsystem" "1234567" -compact 596.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 597.It Li VT Ta BELL Ta RING Ta 598Notification that the console bell has rung. 599See 600.Xr vt 4 601for details. 602.El 603.Pp 604.Bl -column "System" "Subsystem" "1234567" -compact 605.Sy "System" Ta Sy "Subsystem" Ta Sy "Type" Ta Sy "Description" 606.It Li ZFS Ta ZFS Ta Ta 607Events about the ZFS subsystem. 608See 609.Xr zfsd 8 610and 611.Pa /etc/devd/zfs.conf 612for details. 613.El 614.Pp 615.\" 616.\" End of tables 617.\" 618A link state change to UP on the interface 619.Dq Li fxp0 620would result in the following notify event: 621.Bd -literal -offset indent 622system=IFNET subsystem=fxp0 type=LINK_UP 623.Ed 624.Pp 625An AC line state change to 626.Dq offline 627would result in the following event: 628.Bd -literal -offset indent 629system=ACPI subsystem=ACAD notify=0x00 630.Ed 631.Ss Comments 632Comments may appear anywhere that whitespace may appear in a 633configuration file. 634To appeal to programmers of all kinds, they can 635be written in C, C++, or shell/Perl constructs. 636.Pp 637C-style comments start with the two characters 638.Ql /* 639(slash, star) and end with 640.Ql */ 641(star, slash). 642Because they are completely delimited with these characters, 643they can be used to comment only a portion of a line or to span 644multiple lines. 645.Pp 646C-style comments cannot be nested. 647For example, the following is 648not valid because the entire comment ends with the first 649.Ql */ : 650.Bd -literal -offset indent 651/* This is the start of a comment. 652 This is still part of the comment. 653/* This is an incorrect attempt at nesting a comment. */ 654 This is no longer in any comment. */ 655.Ed 656.Pp 657C++-style comments start with the two characters 658.Ql // 659(slash, slash) and continue to the end of the physical line. 660They cannot be continued across multiple physical lines; to have 661one logical comment span multiple lines, each line must use the 662.Ql // 663pair. 664For example: 665.Bd -literal -offset indent 666// This is the start of a comment. The next line 667// is a new comment, even though it is logically 668// part of the previous comment. 669.Ed 670.Ss Notes on Variable Expansion 671To prevent issues with special shell characters, the following happens for each 672variable 673.Ic $foo . 674.Bl -enum 675.It 676The characters 677.Dq $' 678are inserted. 679.It 680The string 681.Dq $foo 682is removed. 683.It 684The value of the 685.Ic foo 686variable is inserted into the buffer with all single quote characters 687prefixed by a backslash. 688.El 689.Pp 690See 691.Xr sh 1 692for what this construct means. 693It is safe in all context, except one: inside single quotes. 694If foo=meta and bar=var, then a rule like the following: 695.Bd -literal -offset indent -compact 696action "echo '$foo $bar'"; 697.Ed 698will be presented to the shell via 699.Xr system 3 700as 701.Bd -literal -offset indent -compact 702echo '$'meta' $'var'' 703.Ed 704which produces the following output: 705.Bd -literal -offset indent -compact 706$meta $var 707.Ed 708as its output. 709This is an unanticipated result. 710A future version of this software will change this behavior. 711Users are discouraged from using single quotes inside 712.Ic action 713value without due care. 714.Pp 715The above should be written as 716.Bd -literal -offset indent -compact 717action "echo $foo' '$bar" 718.Ed 719to produce a single argument to echo. 720Given the above expansion, juxtaposing bare variables with 721single quote expressions will produce the right output, 722regardless of the value of the variable. 723.Sh FILES 724.Bl -tag -width ".Pa /etc/devd.conf" -compact 725.It Pa /etc/devd.conf 726The 727.Xr devd 8 728configuration file. 729.El 730.Sh EXAMPLES 731.Bd -literal 732# 733# This will catch link down events on the interfaces fxp0 and ath0 734# 735notify 0 { 736 match "system" "IFNET"; 737 match "subsystem" "(fxp0|ath0)"; 738 match "type" "LINK_DOWN"; 739 action "logger $subsystem is DOWN"; 740}; 741 742# 743# Match lid open/close events 744# These can be combined to a single event, by passing the 745# value of $notify to the external script. 746# 747notify 0 { 748 match "system" "ACPI"; 749 match "subsystem" "Lid"; 750 match "notify" "0x00"; 751 action "logger Lid closed, we can sleep now!"; 752}; 753 754notify 0 { 755 match "system" "ACPI"; 756 match "subsystem" "Lid"; 757 match "notify" "0x01"; 758 action "logger Lid opened, the sleeper must awaken!"; 759}; 760 761# 762# Match a USB device type 763# 764notify 0 { 765 match "system" "USB"; 766 match "subsystem" "INTERFACE"; 767 match "type" "ATTACH"; 768 match "intclass" "0x0e"; 769 action "logger USB video device attached"; 770}; 771 772# 773# Try to configure ath and iwn devices with pccard_ether 774# as they are attached. 775# 776attach 0 { 777 device-name "(ath|iwn)[0-9]+"; 778 action "/etc/pccard_ether $device-name start"; 779}; 780 781# 782# Stop ath and iwn devices as they are detached from 783# the system. 784# 785detach 0 { 786 device-name "(ath|iwn)[0-9]+"; 787 action "/etc/pccard_ether $device-name stop"; 788}; 789.Ed 790.Pp 791The installed 792.Pa /etc/devd.conf 793has many additional examples. 794.Sh SEE ALSO 795.Xr cam 4 , 796.Xr coretemp 4 , 797.Xr devfs 5 , 798.Xr re_format 7 , 799.Xr devd 8 800.Sh BUGS 801The variable expansion's interaction with single quotes is 802suboptimal and surprising. 803