Hardware: работа с устройствами в Linux (udev, uname, lspci, lscpu, lsusb, sensors; drivers-modules insmod/rmmod, lsmod, depmod, modprobe, modinfo)

• Немного теории.

udev - это демон, который отвечает за виртуальную файловую систему /dev.
/etc/udev/ - каталог настроек демона.
/etc/udev/rules.d/ - каталог с правилами, по которым udev создаёт файлы устройств в /dev.
70-persistent-net.rules - правило для создания сетевых интерфейсов.

Each piece of hardware in the system has an associated file used by the kernel to communicate with it. This type of file is called a device file. There are two types of device files: a character (or raw) device file and a block device file.
The first character in each line entry tells if the file type is block or character. Ab denotes a block device file and a c represents a character device file.

[root@host1 ~]# ll /dev/sd*
brw-rw----. 1 root disk 8, 0 Aug 4 14:13 /dev/sda
brw-rw----. 1 root disk 8, 1 Aug 4 14:13 /dev/sda1
brw-rw----. 1 root disk 8, 2 Aug 4 14:13 /dev/sda2

[root@host1 ~]# ll /dev/usb*
crw-------. 1 root root 250, 0 Aug 4 14:13 /dev/usbmon0
crw-------. 1 root root 250, 1 Aug 4 14:13 /dev/usbmon1
crw-------. 1 root root 250, 2 Aug 4 14:13 /dev/usbmon2

[root@host1 ~]# file /dev/sda
/dev/sda: block special

[root@host1 ~]# file /dev/usbmon0
/dev/usbmon0: character special

# uname –a
Linux host1.example.com 3.10.0-123.el7.x86_64 #1 SMP Mon May 5 11:16:57 EDT 2014 x86_64 x86_64 x86_64 GNU/Linux

The information returned by the second command is:
Linux Kernel name
host1.example.com Hostname of this system
3.10.0-123.el7.x86_64 Kernel release
#1 SMP Mon May 5 11:16:57 EDT 2014 Date and time of this kernel built
x86_64 Machine hardware name
x86_64 Processor type
x86_64 Hardware platform
GNU/Linux Operating system name

lspci

The lspci command displays information about PCI buses and the devices attached to them.

redkin_p@testsmsrobot:~$ lspci
00:00.0 Host bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX Host bridge (rev 01)
00:01.0 PCI bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX AGP bridge (rev 01)
00:07.0 ISA bridge: Intel Corporation 82371AB/EB/MB PIIX4 ISA (rev 08)
00:07.1 IDE interface: Intel Corporation 82371AB/EB/MB PIIX4 IDE (rev 01)
00:07.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 08)
00:07.7 System peripheral: VMware Virtual Machine Communication Interface (rev 10)
00:0f.0 VGA compatible controller: VMware SVGA II Adapter
00:15.0 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.1 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.2 PCI bridge: VMware PCI Express Root Port (rev 01)
03:00.0 Serial Attached SCSI controller: LSI Logic / Symbios Logic SAS1068 PCI-X Fusion-MPT SAS (rev 01)
0b:00.0 Ethernet controller: VMware VMXNET3 Ethernet Controller (rev 01)
13:00.0 Ethernet controller: VMware VMXNET3 Ethernet Controller (rev 01)

redkin.p@govnoserver:~$ lspci | grep VGA
00:02.0 VGA compatible controller: InnoTek Systemberatung GmbH VirtualBox Graphics Adapter

[user1@host1 ~]$ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 18)
01:00.0 VGA compatible controller: NVIDIA Corporation GT218M [GeForce 310M] (rev a2)

[user1@host1 ~]$ lsusb
Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 064e:a136 Suyin Corp. Asus Integrated Webcam [CN031B]
Bus 001 Device 004: ID 0b05:1788 ASUSTek Computer, Inc. BT-270 Bluetooth Adapter
Bus 002 Device 003: ID 058f:6387 Alcor Micro Corp. Flash Drive
Bus 002 Device 004: ID 0458:003a KYE Systems Corp. (Mouse Systems) NetScroll+ Mini Traveler / Genius NetScroll 120

lscpu

[user1@host1 ~]$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0-3
Thread(s) per core:    2
Core(s) per socket:    2
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 37
Model name:            Intel(R) Core(TM) i3 CPU       M 370  @ 2.40GHz
Stepping:              5
CPU MHz:               933.000
BogoMIPS:              4932.50
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              3072K
NUMA node0 CPU(s):     0-3




redkin_p@devastator ~ $ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                8
On-line CPU(s) list:   0-7
Thread(s) per core:    2
Core(s) per socket:    2
Socket(s):             2
Vendor ID:             GenuineIntel
CPU family:            15
Model:                 6
Model name:            Intel(R) Xeon(TM) CPU 3.00GHz
Stepping:              4
CPU MHz:               2999.679
BogoMIPS:              6000.26
Virtualization:        VT-x
L1d cache:             16K
L2 cache:              2048K

[user1@host1 ~]$ sensors
acpitz-virtual-0
Adapter: Virtual device
temp1: +57.0°C (crit = +108.0°C)
nouveau-pci-0100
Adapter: PCI adapter
temp1: +57.0°C (high = +95.0°C, hyst = +3.0°C)
  (crit = +105.0°C, hyst = +5.0°C)
  (emerg = +135.0°C, hyst = +5.0°C)
coretemp-isa-0000
Adapter: ISA adapter
Core 0: +51.0°C (high = +95.0°C, crit = +105.0°C)
Core 2: +46.0°C (high = +95.0°C, crit = +105.0°C)

modules / drivers

Модули ядра в случае с hardware реализуют функционал драйверов этих устройств, хотя в целом модуль далеко не всегда есть драйвер.

Lsmod

Linux provides the lsmod command to view currently loaded modules. Alternatively, you can view them by displaying the contents of the /proc/modules file. Both show module names, memory they are consuming, the number of processes using this and any dependent modules, and a list of dependent modules (if any).

# lsmod | head -n 5
Module Size Used by
joydev 24576 0
hid_generic 16384 0
usbhid 57344 0
hid 139264 2 usbhid,hid_generic
# cat /proc/modules | head -5
joydev 24576 0 - Live 0xffffffffc052c000
hid_generic 16384 0 - Live 0xffffffffc0560000
usbhid 57344 0 - Live 0xffffffffc082a000
hid 139264 2 hid_generic,usbhid, Live 0xffffffffc0501000
igb_uio 16384 0 - Live 0xffffffffc0492000 (OE)

modinfo

The modinfo command can be used to display details about a module. The output shows the module file name, license type, author name, a short description, dependent module names, and other information.
For instance, the following example shows information about a disk mirroring module called dm_mirror:

~# modinfo dm_mirror
filename: /lib/modules/4.19.0-20-amd64/kernel/drivers/md/dm-mirror.ko
license: GPL
author: Joe Thornber
description: device-mapper mirror target
depends: dm-region-hash,dm-mod,dm-log
retpoline: Y
intree: Y
name: dm_mirror
vermagic: 4.19.0-20-amd64 SMP mod_unload modversions 
sig_id: PKCS#7
signer: Debian Secure Boot CA
sig_key: 4B:6E:F5:AB:CA:66:98:25:17:8E:05:2C:84:66:7C:CB:C0:53:1F:8C
sig_hashalgo: sha256
signature: 38:6E:54:9B:40:8A:98:B0:60:FC:53:49:FE:8C:FC:18:A5:22:FB:BA
parm: raid1_resync_throttle:A percentage of time allocated for raid resynchronization (uint)

# modinfo ip_tables
filename: /lib/modules/4.19.0-20-amd64/kernel/net/ipv4/netfilter/ip_tables.ko
alias: ipt_icmp
description: IPv4 packet filter
author: Netfilter Core Team <coreteam@netfilter.org>
license: GPL
depends: x_tables
retpoline: Y
intree: Y
name: ip_tables
vermagic: 4.19.0-20-amd64 SMP mod_unload modversions 
sig_id: PKCS#7
signer: Debian Secure Boot CA
sig_key: 4B:6E:F5:AB:CA:66:98:25:17:8E:05:2C:84:66:7C:CB:C0:53:1F:8C
sig_hashalgo: sha256
signature: 2A:D0:2F:49:E3:38:E1:4C:7E:F7:91:33:4E:84:4C:CD:19:2E:28:45:

modprobe / insmod/ rmmod

modprobe (-r to unload, -v to debug) – Loading and Unloading Modules including dependent modules (для игнорирования зависимостей используются insmod, rmmod).

• Modprobe работает по умолчанию в системе – обнаруживает новый hardware и активирует модули для этого hardware в ядро
• Отключение модулей может быть полезно для безопасности – bluetooth, wifi, usb и проч. В том числе с добавлением запрета модуля по имени в автозагрузку за счет спального blacklist списка – /etc/modprobe.d/blacklist*

Execute the modprobe command to load a module dynamically into memory. This command ensures that any dependent modules are also loaded prior to the specified module. To unload the dm_mirror module along with all unused dependent modules, run the modprobe command with the –r option.

[root@localhost ~]# modprobe -v dm_mirror
insmod /lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/drivers/md/dm-log.ko
insmod /lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/drivers/md/dm-region-hash.ko
insmod /lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/drivers/md/dm-mirror.ko

[root@localhost ~]# modprobe -vr dm_mirror
rmmod dm_mirror
rmmod dm_region_hash
rmmod dm_log

depmod

Linux detects hardware devices and loads appropriate modules automatically; however, there may be instances when a device is left undetected or added online (as in the case of SAN disk allocation). In such a situation, execute the depmod command to force the system to scan the hardware, find appropriate modules for the new devices, create required module dependencies, and update the /lib/modules/3.10.0-327.36.2.el7.x86_64/modules.dep file, in addition to creating and updating several corresponding map files in the /lib/modules/3.10.0-327.36.2.el7.x86_64 directory.

[root@localhost ~]# depmod -v | head -5
/lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/arch/x86/crypto/ablk_helper.ko needs "cryptd_alloc_ablkcipher": /lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/crypto/cryptd.ko
/lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/arch/x86/crypto/camellia-x86_64.ko needs "glue_cbc_encrypt_128bit": /lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/arch/x86/crypto/glue_helper.ko
/lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/arch/x86/crypto/camellia-x86_64.ko needs "lrw_free_table": /lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/crypto/lrw.ko
/lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/arch/x86/crypto/camellia-x86_64.ko needs "xts_crypt": /lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/crypto/xts.ko
/lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/arch/x86/crypto/blowfish-x86_64.ko needs "blowfish_setkey": /lib/modules/3.10.0-327.36.2.el7.x86_64/kernel/crypto/blowfish_common.ko

[root@localhost ~]# ls /lib/modules/3.10.0-327.36.2.el7.x86_64/ | grep modules
modules.alias
modules.alias.bin
modules.block
modules.builtin
modules.builtin.bin
modules.dep
modules.dep.bin
modules.devname
modules.drm
modules.modesetting
modules.networking
modules.order
modules.softdep
modules.symbols
modules.symbols.bin