[英]Linux: how do i know the module that exports a device node?
如果有一个/ dev设备节点及其主要/次要编号,我如何知道导出该节点的内核模块名称?
Short answer : 简短回答:
cd /sys/dev/char/major:minor/device/driver/
ls -al | grep module
Each device is generally associated with a driver, and this is all what the "device model" is about. 每个设备通常与驱动程序相关联,这就是“设备模型”的全部内容。 The
sysfs
filesystem contains a representation of this devices and their associated driver. sysfs
文件系统包含此设备及其相关驱动程序的表示。 Unfortuantely, it seems not all sysfs have a representation of the device nodes, so this applyd only if your /sys directory contains a /dev directory. 不幸的是,似乎并非所有sysfs都具有设备节点的表示,因此仅当/ sys目录包含/ dev目录时才应用此选项。 Let's take an example, with
/dev/video0
让我们以
/dev/video0
On my board, ls -al /dev/video0
output is 在我的主板上,
ls -al /dev/video0
输出是
crw------- 1 root root 81, 0 Jan 1 00:00 video0
So major number is 81 and minor number is 0. Let's dive into sysfs : 所以主要数字是81而次要数字是0.让我们深入了解sysfs:
# cd /sys
# ls
block class devices fs module
bus dev firmware kernel
The sys/dev
directory contains entry for the char and block devices of the system : sys/dev
目录包含sys/dev
的char和块设备的条目:
# cd dev
# cd char
# ls
10:61 13:64 1:3 1:8 249:0 252:0 29:0 4:65 81:0 89:1
10:62 1:1 1:5 1:9 250:0 253:0 29:1 5:0 81:2
10:63 1:11 1:7 248:0 251:0 254:0 4:64 5:1 81:3
What the hell are this links with strange names ? 这到底与陌生的名字有什么联系? Remember the major and minor number, 81 and 0 ?
记住主要和次要数字,81和0? Let's follow this link :
我们来这个链接:
#cd major:minor (ie 81:0)
#ls -al
drwxr-xr-x 2 root root 0 Jan 1 01:56 .
drwxr-xr-x 3 root root 0 Jan 1 01:56 ..
-r--r--r-- 1 root root 4096 Jan 1 01:56 dev
lrwxrwxrwx 1 root root 0 Jan 1 01:56 device -> ../../../vpfe-capture
-r--r--r-- 1 root root 4096 Jan 1 01:56 index
-r--r--r-- 1 root root 4096 Jan 1 01:56 name
lrwxrwxrwx 1 root root 0 Jan 1 01:56 subsystem -> ../../../../../class/video4linux
-rw-r--r-- 1 root root 4096 Jan 1 01:56 uevent
Now we can see that this device nod, which is how the device is presented to userspace, is associated with a kernel device. 现在我们可以看到这个设备点头,即设备呈现给用户空间的方式,与内核设备相关联。 This association is made through a link.
此关联是通过链接进行的。 If we follow this link, we end up in a directory, with a driver link.
如果我们按照此链接,我们最终会进入一个带有驱动程序链接的目录。 The name of the driver is usually the name of the module :
驱动程序的名称通常是模块的名称:
# ls -al
drwxr-xr-x 3 root root 0 Jan 1 01:56 .
drwxr-xr-x 25 root root 0 Jan 1 00:00 ..
lrwxrwxrwx 1 root root 0 Jan 1 01:56 driver -> ../../../bus/platform/drivers/vpfe-capture
-r--r--r-- 1 root root 4096 Jan 1 01:56 modalias
lrwxrwxrwx 1 root root 0 Jan 1 01:56 subsystem -> ../../../bus/platform
-rw-r--r-- 1 root root 4096 Jan 1 01:56 uevent
drwxr-xr-x 3 root root 0 Jan 1 01:56 video4linux
So here the name of the module is vpfe_capture 所以这里模块的名称是vpfe_capture
The answer to this question is most likely different based on a number of factors. 基于许多因素,这个问题的答案很可能是不同的。 For example, if you're running udev, devfs, pre-devfs, etc.
例如,如果您正在运行udev,devfs,pre-devfs等。
If you're using Ubuntu (or another equally modern distro) the udevadm
command might be what you want. 如果你正在使用Ubuntu(或其他同样现代的发行版),
udevadm
命令可能就是你想要的。
% udevadm info -q path -n /dev/cdrom
/devices/pci0000:00/0000:00:1f.1/host3/target3:0:0/3:0:0:0/block/sr0
So, my /dev/cdrom is provided by the sr
driver, which resides in the sr_mod
kernel module. 所以,我的/ dev / cdrom是由
sr
驱动程序提供的,它位于sr_mod
内核模块中。 I don't know of a command that takes /dev/cdrom
as an argument and prints sr_mod
as output. 我不知道将
/dev/cdrom
作为参数的命令,并将sr_mod
作为输出打印。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.