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d3db5e5e | 1 | .TH UDEV 8 "October 2003" "" "Linux Administrator's Manual" |
04db8c9e | 2 | .SH NAME |
d3db5e5e | 3 | udev \- Linux configurable dynamic device naming support |
04db8c9e | 4 | .SH SYNOPSIS |
eb13ff87 | 5 | .BI udev " hotplug-subsystem" |
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6 | .SH "DESCRIPTION" |
7 | .B udev | |
d3db5e5e | 8 | creates or removes device node files usually located in the /dev directory. |
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9 | Its goal is to provide a dynamic device directory that contains only the files |
10 | for devices that are actually present. | |
11 | .P | |
d3db5e5e | 12 | As part of the |
13 | .B hotplug | |
14 | subsystem, | |
15 | .B udev | |
eb13ff87 | 16 | is executed if a kernel device is added or removed from the system. |
d3db5e5e | 17 | On device creation, |
18 | .B udev | |
eb13ff87 | 19 | reads the sysfs directory of the given device to collect device attributes |
d3db5e5e | 20 | like label, serial number or bus device number. |
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21 | These attributes are treated as a key |
22 | to determine a unique name for device file creation. | |
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23 | .B udev |
24 | maintains a database for devices present on the system. | |
eb13ff87 | 25 | .br |
d3db5e5e | 26 | On device removal, |
27 | .B udev | |
d4112087 | 28 | queries the internal database for the name of the device file to be deleted. |
eb13ff87 | 29 | .SH "CONFIGURATION" |
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30 | .B udev |
31 | expects its configuration at | |
d4112087 | 32 | .I /etc/udev/udev.config. |
d3db5e5e | 33 | The file consists of a set of lines. All empty lines and |
34 | lines beginning with a '#' will be ignored. | |
35 | .br | |
3370fb21 | 36 | Every line defines the mapping between device attributes and the device file |
37 | name. It starts with a keyword defining the method used to match, followed by | |
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38 | one ore more keys to compare and the filename for the device. If no matching |
39 | configuration is found, the default kernel device name is used. | |
3370fb21 | 40 | .P |
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41 | The line format is: |
42 | .RS | |
43 | .sp | |
44 | .I method, key,[key,...] name | |
45 | .sp | |
46 | .RE | |
47 | where valid methods with corresponding keys are: | |
d3db5e5e | 48 | .TP |
67922099 GKH |
49 | .B CALLOUT |
50 | calling external program, that returns a string to match | |
51 | .br | |
52 | keys: \fBBUS\fP, \fBPROGRAM\fP, \fBID\fP | |
53 | .TP | |
d3db5e5e | 54 | .B LABEL |
55 | device label or serial number, like USB serial number, SCSI UUID or | |
56 | file system label | |
3370fb21 | 57 | .br |
58 | keys: \fBBUS\fP, \fIsysfs_attribute\fP | |
d3db5e5e | 59 | .TP |
60 | .B NUMBER | |
61 | device number on the bus, like PCI bus id | |
3370fb21 | 62 | .br |
63 | keys: \fBBUS\fP, \fBID\fP | |
d3db5e5e | 64 | .TP |
65 | .B TOPOLOGY | |
66 | device position on bus, like physical port of USB device | |
3370fb21 | 67 | .br |
68 | keys: \fBBUS\fP, \fBPLACE\fP | |
d3db5e5e | 69 | .TP |
70 | .B REPLACE | |
71 | string replacement of the kernel device name | |
3370fb21 | 72 | .br |
73 | key: \fBKERNEL_NAME\fP | |
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74 | .P |
75 | The methods are applied in the following order: | |
3370fb21 | 76 | .B CALLOUT |
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77 | , |
78 | .B LABEL | |
79 | , | |
80 | .B NUMBER | |
81 | , | |
82 | .B TOPOLOGY | |
83 | , | |
84 | .B REPLACE | |
eb13ff87 | 85 | .P |
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86 | The |
87 | .B NAME | |
88 | and | |
89 | .B PROGRAM | |
90 | fields support simple printf-like string subtitution: | |
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91 | .RS |
92 | .TP | |
93 | .B %n | |
94 | the "kernel number" of the device | |
95 | for example, 'sda3' has a "kernel number" of '3' | |
96 | .TP | |
97 | .B %M | |
98 | the kernel major number for the device | |
99 | .TP | |
100 | .B %m | |
101 | the kernel minor number for the device | |
102 | .TP | |
103 | .B %b | |
104 | the bus id for the device | |
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105 | .TP |
106 | .B %c | |
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107 | the CALLOUT program returned string |
108 | (this does not work within the PROGRAM field for the obvious reason.) | |
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109 | .TP |
110 | .B %D | |
111 | Use the devfs style disk name for this device. | |
112 | For partitions, this will result in 'part%n' | |
113 | If this is not a partition, it will result in 'disk' | |
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114 | .RE |
115 | .P | |
d4112087 | 116 | A sample \fIudev.conf\fP might look like this: |
eb13ff87 | 117 | .sp |
d3db5e5e | 118 | .nf |
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119 | # if /sbin/scsi_id returns "OEM 0815" device will be called disk1 |
120 | CALLOUT, BUS="scsi", PROGRAM="/sbin/scsi_id", ID="OEM 0815", NAME="disk1" | |
121 | ||
d3db5e5e | 122 | # USB printer to be called lp_color |
123 | LABEL, BUS="usb", serial="W09090207101241330", NAME="lp_color" | |
124 | ||
125 | # sound card with PCI bus id 00:0b.0 to be called dsp | |
3370fb21 | 126 | NUMBER, BUS="pci", ID="00:0b.0", NAME="dsp" |
d3db5e5e | 127 | |
128 | # USB mouse at third port of the second hub to be called mouse1 | |
3370fb21 | 129 | TOPOLOGY, BUS="usb", PLACE="2.3", NAME="mouse1" |
d3db5e5e | 130 | |
131 | # ttyUSB1 should always be called pda | |
132 | REPLACE, KERNEL="ttyUSB1", NAME="pda" | |
3370fb21 | 133 | |
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134 | # USB webcams to be called webcam0, webcam1, ... |
135 | LABEL, BUS="usb", model="WebCam Version 3", NAME="webcam%n" | |
d3db5e5e | 136 | .fi |
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137 | .P |
138 | Permissions and ownership for the created device files may specified at | |
d4112087 | 139 | .I /etc/udev/udev.permissions. |
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140 | The file consists of a set of lines. All empty lines and |
141 | lines beginning with a '#' will be ignored. | |
142 | .br | |
5b8ba50a | 143 | Every line lists a device name followed by owner, group and permission |
d0a4a110 KS |
144 | mode. All values are separated by colons. The name field may end with a |
145 | wildcard to apply the values to a whole class of devices. | |
67922099 | 146 | .br |
5b8ba50a KS |
147 | If |
148 | .B udev | |
149 | was built using klibc or is used before the user database is accessible (e.g. | |
150 | .B initrd | |
151 | ), only numeric owner and group values may be used. | |
eb13ff87 | 152 | .sp |
d4112087 | 153 | A sample \fIudev.permissions\fP might look like this: |
eb13ff87 KS |
154 | .sp |
155 | .nf | |
156 | #name:user:group:mode | |
5b8ba50a | 157 | input/*:root:root:644 |
d0a4a110 | 158 | ttyUSB1:0:8:0660 |
5b8ba50a | 159 | video*:root:video:0660 |
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160 | dsp1:::0666 |
161 | .fi | |
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162 | .SH "FILES" |
163 | .nf | |
164 | .ft B | |
165 | .ft | |
166 | /sbin/udev udev program | |
167 | /etc/udev/* udev config and database files | |
168 | /etc/hotplug.d/default/udev.hotplug hotplug symlink to udev program | |
169 | .fi | |
170 | .LP | |
171 | .SH "SEE ALSO" | |
eb13ff87 | 172 | .BR hotplug (8) |
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173 | .PP |
174 | The | |
175 | .I http://linux-hotplug.sourceforge.net/ | |
176 | web site. | |
177 | .SH AUTHORS | |
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178 | .B udev |
179 | was developed by Greg Kroah-Hartman <greg@kroah.com> with much help from | |
04db8c9e | 180 | Dan Stekloff <dsteklof@us.ibm.com> and many others. |