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Diffstat (limited to 'static/openbsd/man4/hotplug.4')
| -rw-r--r-- | static/openbsd/man4/hotplug.4 | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/static/openbsd/man4/hotplug.4 b/static/openbsd/man4/hotplug.4 new file mode 100644 index 00000000..9f37e17b --- /dev/null +++ b/static/openbsd/man4/hotplug.4 @@ -0,0 +1,104 @@ +.\" $OpenBSD: hotplug.4,v 1.6 2015/09/14 17:09:26 schwarze Exp $ +.\" +.\" Copyright (c) 2004 Alexander Yurchenko <grange@openbsd.org> +.\" +.\" Permission to use, copy, modify, and distribute this software for any +.\" purpose with or without fee is hereby granted, provided that the above +.\" copyright notice and this permission notice appear in all copies. +.\" +.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +.\" +.Dd $Mdocdate: September 14 2015 $ +.Dt HOTPLUG 4 +.Os +.Sh NAME +.Nm hotplug +.Nd devices hot plugging +.Sh SYNOPSIS +.Cd "pseudo-device hotplug 1" +.Pp +.In sys/types.h +.In sys/device.h +.In sys/hotplug.h +.Sh DESCRIPTION +The +.Nm +pseudo-device passes device attachment and detachment events to +userland. +When a device attaches or detaches, the corresponding event is queued. +The events can then be obtained from the queue through the +.Xr read 2 +call on the +.Pa /dev/hotplug +device file. +Once an event has been read, it's deleted from the queue. +The event queue has a limited size and if it's full all new events will be +dropped. +Each event is described with the following structure declared in the +.In sys/hotplug.h +header file: +.Bd -literal -offset indent +struct hotplug_event { + int he_type; /* event type */ + enum devclass he_devclass; /* device class */ + char he_devname[16]; /* device name */ +}; + +.Ed +The +.Va he_type +field describes the event type and can be either +.Dv HOTPLUG_DEVAT +for device attachment or +.Dv HOTPLUG_DEVDT +for detachment. +The +.Va he_devclass +field describes the device class. +All device classes can be found in the +.In sys/device.h +header file: +.Bd -literal -offset indent +enum devclass { + DV_DULL, /* generic, no special info */ + DV_CPU, /* CPU (carries resource utilization) */ + DV_DISK, /* disk drive (label, etc) */ + DV_IFNET, /* network interface */ + DV_TAPE, /* tape device */ + DV_TTY /* serial line interface */ +}; + +.Ed +The +.Va he_devname +is a device name including unit number, e.g.\& +.Pa sd1 . +.Pp +Only one structure can be read per call. +If there are no events in the queue, the +.Xr read 2 +call will block until an event appears. +.Sh DIAGNOSTICS +.Bl -diag +.It "hotplug: event lost, queue full" +New events will be dropped until all pending events have been read. +.El +.Sh SEE ALSO +.Xr read 2 , +.Xr hotplugd 8 +.Sh HISTORY +The +.Nm +device first appeared in +.Ox 3.6 . +.Sh AUTHORS +The +.Nm +driver was written by +.An Alexander Yurchenko Aq Mt grange@openbsd.org . |