linux专题

Linux内核 特殊文件系统

2019-08-27  本文已影响0人  Mr_Michael

特殊文件系统

1.proc文件系统

1）proc各目录说明
2）进程目录/proc/[pid]说明

2.sysfs伪文件系统

1）/sys目录说明
2）sysfs与proc的关系

3.devfs设备文件系统

4.udev设备管理器

​ udev 是Linux kernel 2.6系列的设备管理器。它主要的功能是管理/dev目录底下的设备节点。它同时也是用来接替devfs及hotplug的功能，这意味着它要在添加/删除硬件时处理/dev目录以及所有用户空间的行为，包括加载firmware时。

1）运行方式
image
2）udev组成

udev系统可以分为三个部分：

$ udevadm info -a -p /sys/class/net/eth1

Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.

  looking at device '/devices/1003000.pcie/pci0000:00/0000:00:02.0/0000:01:00.0/net/eth1':
    KERNEL=="eth1"
    SUBSYSTEM=="net"
    DRIVER==""
    ATTR{addr_assign_type}=="0"
    ATTR{addr_len}=="6"
    ATTR{address}=="00:04:4b:e5:da:f3"
    ATTR{broadcast}=="ff:ff:ff:ff:ff:ff"
    ATTR{carrier}=="1"
    ATTR{carrier_changes}=="2"
    ATTR{dev_id}=="0x0"
    ATTR{dev_port}=="0"
    ATTR{dormant}=="0"
    ATTR{duplex}=="full"
    ATTR{flags}=="0x1003"
    ATTR{gro_flush_timeout}=="0"
    ATTR{ifalias}==""
    ATTR{ifindex}=="4"
    ATTR{iflink}=="4"
    ATTR{link_mode}=="0"
    ATTR{mtu}=="1500"
    ATTR{netdev_group}=="0"
    ATTR{operstate}=="up"
    ATTR{proto_down}=="0"
    ATTR{speed}=="1000"
    ATTR{tx_queue_len}=="1000"
    ATTR{type}=="1"

  looking at parent device '/devices/1003000.pcie/pci0000:00/0000:00:02.0/0000:01:00.0':
    KERNELS=="0000:01:00.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="r8168"
    ATTRS{broken_parity_status}=="0"
    ATTRS{class}=="0x020000"
    ATTRS{consistent_dma_mask_bits}=="64"
    ATTRS{device}=="0x8168"
    ATTRS{dma_mask_bits}=="64"
    ATTRS{driver_override}=="(null)"
    ATTRS{enable}=="1"
    ATTRS{irq}=="405"
    ATTRS{local_cpulist}=="0-3"
    ATTRS{local_cpus}=="f"
    ATTRS{msi_bus}=="1"
    ATTRS{subsystem_device}=="0x8168"
    ATTRS{subsystem_vendor}=="0x10ec"
    ATTRS{vendor}=="0x10ec"

  looking at parent device '/devices/1003000.pcie/pci0000:00/0000:00:02.0':
    KERNELS=="0000:00:02.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="pcieport"
    ATTRS{broken_parity_status}=="0"
    ATTRS{class}=="0x060400"
    ATTRS{consistent_dma_mask_bits}=="32"
    ATTRS{device}=="0x0faf"
    ATTRS{dma_mask_bits}=="32"
    ATTRS{driver_override}=="(null)"
    ATTRS{enable}=="1"
    ATTRS{irq}=="83"
    ATTRS{local_cpulist}=="0-3"
    ATTRS{local_cpus}=="f"
    ATTRS{msi_bus}=="1"
    ATTRS{subsystem_device}=="0x0000"
    ATTRS{subsystem_vendor}=="0x10de"
    ATTRS{vendor}=="0x10de"

  looking at parent device '/devices/1003000.pcie/pci0000:00':
    KERNELS=="pci0000:00"
    SUBSYSTEMS==""
    DRIVERS==""

  looking at parent device '/devices/1003000.pcie':
    KERNELS=="1003000.pcie"
    SUBSYSTEMS=="platform"
    DRIVERS=="tegra-pcie"
    ATTRS{driver_override}=="(null)"
3）udev规则和文件
4）编写udev规则步骤

​ 编写udev规则

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