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30 .Nd "device state change daemon"
39 daemon provides a way to have userland programs run when certain
42 The following options are accepted.
43 .Bl -tag -width ".Fl f Ar file"
45 Run in the foreground instead of becoming a daemon and log additional information for debugging.
47 Use configuration file
49 instead of the default
53 is specified more than once, the last file specified is used.
55 Limit concurrent socket connections to
57 The default connection limit is 10.
59 Do not process all pending events before becoming a daemon.
60 Instead, call daemon right away.
63 Only log messages at priority LOG_WARNING or above.
65 .Sh IMPLEMENTATION NOTES
69 is a system daemon that runs in the background all the time.
70 Whenever a device is added to or removed from the device tree,
72 will execute actions specified in
78 when an Ethernet adapter is added to the system, and kill the
80 instance when the same adapter is removed.
81 Another example would be for
83 to use a table to locate and load via
85 the proper driver for an unrecognized device that is added to the system.
93 This device driver has hooks into the device configuration system.
94 When nodes are added or deleted from the tree, this device will
95 deliver information about the event to
99 has parsed the message, it will search its action list for that kind
100 of event and perform the action with the highest matching value.
101 For most mundane uses, the default handlers are adequate.
102 However, for more advanced users, the power is present to tweak every
103 aspect of what happens.
110 or the alternate configuration file specified with a
112 option and uses that file to drive the rest of the process.
113 While the format of this file is described in
115 some basics are covered here.
119 section, one can define multiple directories to search
121 The default config file specifies
124 .Pa /usr/local/etc/devd
125 as directories to search.
126 All files in these directories whose names match the pattern
129 These files are intended to be installed by third party vendors that
130 wish to hook into the
132 system without modifying the user's other
137 allows only one active reader,
139 multiplexes it, forwarding all events to any number of connected clients.
140 Clients connect by opening the SOCK_SEQPACKET
143 .Pa /var/run/devd.seqpacket.pipe .
145 .Bl -tag -width ".Pa /var/run/devd.seqpacket.pipe" -compact
146 .It Pa /etc/devd.conf
150 .It Pa /var/run/devd.seqpacket.pipe
153 to communicate with its clients.
154 .It Pa /var/run/devd.pipe
155 A deprecated socket retained for use with old clients.
163 utility first appeared in