Linux:我怎么知道导出设备节点的模块? [英] Linux: how do i know the module that exports a device node?

问题描述

如果有一个/dev设备节点及其主要/次要数字，我怎么知道导出该节点的内核模块名称?

If a have a /dev device node and its major/minor numbers how do i know the kernel module name that exported this node?

推荐答案

简短答案:

cd /sys/dev/char/major:minor/device/driver/
ls -al | grep module

每个设备通常与一个驱动程序关联，而这就是设备模型"的全部含义. sysfs文件系统包含此设备及其关联的驱动程序的表示.不幸的是，似乎不是所有的sysfs都有设备节点的表示形式，因此仅当/sys目录包含/dev目录时才适用. 让我们举一个例子，用/dev/video0

Each device is generally associated with a driver, and this is all what the "device model" is about. The sysfs filesystem contains a representation of this devices and their associated driver. 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. Let's take an example, with /dev/video0

在我的板上，ls -al /dev/video0输出是

crw-------    1 root     root      81,   0 Jan  1 00:00 video0

所以主号码是81，次号码是0. 让我们深入了解sysfs:

So major number is 81 and minor number is 0. Let's dive into sysfs :

# cd /sys
# ls
block     class     devices   fs        module
bus       dev       firmware  kernel

sys/dev目录包含系统的char和block设备的条目:

The sys/dev directory contains entry for the char and block devices of the system :

# 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

这跟陌生名字的链接到底是什么? 还记得主要数字和次要数字81和0吗? 让我们点击此链接:

What the hell are this links with strange names ? Remember the major and minor number, 81 and 0 ? Let's follow this link :

#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

现在，我们可以看到该设备nod与内核设备相关联，这是将设备呈现给用户空间的方式.该关联是通过链接建立的.如果遵循此链接，则最终会到达带有驱动程序链接的目录中.驱动程序的名称通常是模块的名称:

Now we can see that this device nod, which is how the device is presented to userspace, is associated with a kernel device. This association is made through a link. If we follow this link, we end up in a directory, with a driver link. The name of the driver is usually the name of the module :

# 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

所以这里的模块名称是vpfe_capture

So here the name of the module is vpfe_capture

这篇关于Linux:我怎么知道导出设备节点的模块?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！