Linux：我怎么知道导出设备节点的模块？

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

2 个解决方案

#1

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. 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

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。 sysfs文件系统包含此设备及其相关驱动程序的表示。不幸的是，似乎并非所有sysfs都具有设备节点的表示，因此仅当您的/ sys目录包含/ dev目录时才应用此选项。让我们以/ dev / video0为例

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目录包含系统的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 ? Remember the major and minor number, 81 and 0 ? Let's follow this link :

这到底与陌生的名字有什么联系？记住主要和次要数字，81和0？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. 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 :

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。此关联是通过链接进行的。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。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

#2

The answer to this question is most likely different based on a number of factors. For example, if you're running udev, devfs, pre-devfs, etc.

这个问题的答案很可能基于许多因素而有所不同。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. I don't know of a command that takes /dev/cdrom as an argument and prints sr_mod as output.

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。我不知道将/ dev / cdrom作为参数的命令并将sr_mod作为输出打印。

#1