GNU/Linux Tips
目录 |
1 Kernel代码格式化
kernel source tree 的 scripts/ 下有一个 Lindent 的脚本:
#!/bin/sh PARAM="-npro -kr -i8 -ts8 -sob -l80 -ss -ncs -cp1" RES=`indent --version` V1=`echo $RES | cut -d' ' -f3 | cut -d'.' -f1` V2=`echo $RES | cut -d' ' -f3 | cut -d'.' -f2` V3=`echo $RES | cut -d' ' -f3 | cut -d'.' -f3` if [ $V1 -gt 2 ]; then PARAM="$PARAM -il0" elif [ $V1 -eq 2 ]; then if [ $V2 -gt 2 ]; then PARAM="$PARAM -il0"; elif [ $V2 -eq 2 ]; then if [ $V3 -ge 10 ]; then PARAM="$PARAM -il0" fi fi fi indent $PARAM "$@"
2 udev
$ lsusb 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 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 003 Device 002: ID 413c:2003 Dell Computer Corp. Keyboard Bus 002 Device 003: ID 413c:3016 Dell Computer Corp. Optical 5-Button Wheel Mouse Bus 002 Device 016: ID 18d1:4e22 Google Inc. Nexus S (debug)
Bus 002 Device 016 就是我的手机,对应的设备节点是 /dev/bus/usb/002/016
如下命令查看设备信息:
$ udevadm info -q all -n /dev/bus/usb/002/016 P: /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.6 N: bus/usb/002/016 E: BUSNUM=002 E: DEVNAME=/dev/bus/usb/002/016 E: DEVNUM=016 E: DEVPATH=/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.6 E: DEVTYPE=usb_device E: DRIVER=usb E: ID_BUS=usb E: ID_MEDIA_PLAYER=google_nexus-s E: ID_MODEL=SGH-T959 E: ID_MODEL_ENC=SGH-T959 E: ID_MODEL_ID=4e22 E: ID_REVISION=0231 E: ID_SERIAL=samsung_SGH-T959_32334071DA1D00EC E: ID_SERIAL_SHORT=32334071DA1D00EC E: ID_USB_INTERFACES=:080650:ff4201: E: ID_VENDOR=samsung E: ID_VENDOR_ENC=samsung E: ID_VENDOR_ID=18d1 E: MAJOR=189 E: MINOR=143 E: PRODUCT=18d1/4e22/231 E: SUBSYSTEM=usb E: TAGS=:udev-acl: E: TYPE=0/0/0 E: UDEV_LOG=3 E: USEC_INITIALIZED=599355697049
或者:
$ udevadm info -q path -n /dev/bus/usb/002/016 /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.6 $ udevadm info -a -p $(udevadm info -q path -n /dev/bus/usb/002/016) looking at device '/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.6': KERNEL=="2-1.6" SUBSYSTEM=="usb" DRIVER=="usb" ATTR{configuration}=="" ATTR{bNumInterfaces}==" 2" ATTR{bConfigurationValue}=="1" ...... ......
根据 http://www.reactivated.net/writing_udev_rules.html#basic 写一个 udev rules 文件 /etc/udev/rules.d/62-android.rules:
# 匹配上设备则将设备节点文件的 mode 改为 0666,建一个 /dev/GalasyS 的符号链接指向它 SUBSYSTEM=="usb", ENV{ID_VENDOR_ID}=="18d1", ENV{ID_MODEL}=="Galaxy", MODE="0666", SYMLINK+="GalaxyS" SUBSYSTEM=="usb", ENV{ID_VENDOR_ID}=="18d1", ENV{ID_MODEL_ID}=="4e22", MODE="0666", SYMLINK+="GalaxyS" SUBSYSTEM=="usb", ATTR{idVendor}=="18d1", ATTR{idProduct}=="4e22", ATTR{product}=="Galaxy" MODE="0666", SYMLINK+="GalaxyS"
如对某一行 rule 没底,可用如下命令测试这个 rule:
$ udevadm test --action='"usb", ENV{ID_VENDOR_ID}=="18d1", ENV{ID_MODEL}=="Galaxy", MODE="0666", SYMLINK+="GalaxyS"' $(udevadm info -q path -n /dev/bus/usb/002/016) ...... udev_node_add: creating device node '/dev/bus/usb/002/016', devnum=189:143, mode=0664, uid=0, gid=0 udev_node_mknod: preserve file '/dev/bus/usb/002/016', because it has correct dev_t udev_node_mknod: preserve permissions /dev/bus/usb/002/016, 020664, uid=0, gid=0 node_symlink: preserve already existing symlink '/dev/char/189:143' to '../bus/usb/002/016' ......
确定后重启 udev 即可:
sudo service udev restart
3 Mounting partition from VDI image
$ od -j344 -N4 -td4 /work/FreeDos.vdi | awk 'NR==1{print $2;}' 8192 $ sudo losetup -f --show -o 8192 /work/FreeDos.vdi /dev/loop0 $ sudo fdisk -lu /dev/loop0 Disk /dev/loop0: 113 MB, 113246208 bytes 16 heads, 63 sectors/track, 219 cylinders, total 221184 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/loop0p1 * 63 1023119 511528+ 6 FAT16 $ sudo mount -o loop,offset=$((512*63)) /dev/loop0 /mnt $ ls /mnt/ AUTOEXEC.BAT BOOTSECT.BIN COMMAND.COM FDCONFIG.SYS FDOS KERNEL.SYS $ sudo umount /mnt $ sudo losetup -d /dev/loop0 $ VBoxManage clonehd /work/FreeDos.vdi /work/freedos.vdi --format VDI --variant Fixe
4 Mount a disk image
$ sudo losetup -fv ./rasper-pi.img Loop device is /dev/loop0 $ sudo kpartx -av /dev/loop0 add map loop0p1 (252:0): 0 114688 linear /dev/loop0 8192 add map loop0p2 (252:1): 0 7917568 linear /dev/loop0 122880 $ sudo mount /dev/mapper/loop0p2 /mnt $ ls /mnt/ bin boot dev etc home lib lost+found media mnt opt proc root run sbin selinux srv sys tmp usr var
5 GDB Tips
1. 查看寄存器
(gdb) i r (gdb) i r a # 查看所有寄存器(包括浮点、多媒体) (gdb) i r esp (gdb) i r pc
2. 查看内存
(gdb) x /wx 0x80040000 # 以16进制显示指定地址处的数据 (gdb) x /8x $esp (gdb) x /16x $esp+12 (gdb) x /16s 0x86468700 # 以字符串形式显示指定地址处的数据 (gdb) x /24i 0x8048a51 # 以指令形式显示指定地址处的数据(24条)
3. 修改寄存器的值
(gdb) set $v0 = 0x004000000 (gdb) set $epc = 0xbfc00000
4. 修改内存的值
(gdb) set {unsigned int}0x8048a51=0x0 (gdb) set *(unsigned int*)0x8048a54=0x55aa55aa
5. 内存搜索
Usage: find <start> <end> <count> <value> (gdb) define find set $ptr = $arg0 set $cnt = 0 while ( ($ptr<=$arg1) && ($cnt<$arg2) ) if ( *(unsigned int *)$ptr == $arg3 ) x /wx $ptr set $cnt = $cnt + 1 end set $ptr = $ptr + 4 end end
6. 断点、监测点
(gdb) b *0x80400000 (gdb) watch *(unsigned int *)0xbffff400==0x90909090
6 Strace Tips
1. strace 是一个诊断调试工具,其借助内核 ptrace 机制,跟踪目标进程所执行的系统调用和收到的信号。
2. 常用选项
-o filename: 将输出信息写到文件filename中,默出输出到标准错误(stderr) -c: 统计输出,包括每个系统调用的执行时间、被调用次数等 -tt: 每行前加上相对时间戳 -e trace=open,close: 只跟踪open, close -e trace=file: 只跟踪以文件名为参数的的调用,等价于 -e trace=open,stat,chmod,unlink... -e trace=process: 进程管理相关 -e trace=network: 网络相关 -e trace=ipc: 进程间通信相关 -e trace=signal: 信号相关 -e verbose=close,open: vebose模式输出(结构体成员都输出) -e abbrev=open: 默认情况下所有调用的显示都是abbreviate,只要给这个选项,就只有open为abbrev -e raw=open: open 调用以16进制形式输出参数 -e read=3,5: 显示文件描述符3、5的读取数据 -e write=3,5 -p pid: 绑定到pid对应的正在运行的进程。此参数常用来调试后台进程 -f: 除了跟踪当前进程外,还跟踪其子进程 -ff: 当跟踪多个进程且输出到文件时,使用该选项则将各个进程的跟踪信息写入各个filename.pid中
7 Git
翻墙代理:
git config --global http.proxy 'socks5://127.0.0.1:8080'
git server:
$ apt-get install git-daemon-sysvinit $ cat /etc/default/git-daemon GIT_DAEMON_ENABLE=true GIT_DAEMON_USER=gitdaemon GIT_DAEMON_DIRECTORY=/var/data/git GIT_DAEMON_BASE_PATH=/var/data/git GIT_DAEMON_OPTIONS="--export-all --enable=upload-pack --enable=upload-archive --enable=receive-pack --informative-errors"
修改.git/config添加如下代码:
[receive] denyCurrentBranch = ignore
在初始化远程仓库时最好使用 git --bare init 而不要使用 git init
如果使用了git init初始化,则远程仓库的目录下,也包含work tree,当本地仓库向远程仓库push时, 如果远程仓库正在push的分支上(不在push分支,没有问题), 那么push后的结果不会反应在work tree上, 也即在远程仓库的目录下对应的文件还是之前的内容,必须得使用git reset --hard才能看到push后的内容
8 tshark
抓包 HTTP 协议分析:
$ tshark tcp port 80 or tcp port 443 -V -R "http.request || http.response" -i eth1 | sed -rn '/Hypertext Transfer Protocol/{:a;N;/ \\r\\n:?/{/.*/p;d};ba}'
只显示 GET 类请求的头:
$ tshark 'tcp port 80' -R 'http.request.method == "GET" || http.request.method == "HEAD"' -i eth1
9 ATA Secure Erase
https://ata.wiki.kernel.org/index.php/ATA_Secure_Erase
10 Port Scan
# TCP Connect scanning # nmap -v -sT localhost # nmap -v -sT 192.168.31.0/24 # nmap TCP SYN (half-open) scanning # nmap -v -sS localhost # nmap TCP FIN scanning # nmap -v -sF localhost # nmap TCP Xmas tree scanning # nmap -v -sX localhost # nmap TCP Null scanning # nmap -v -sN localhost nmap TCP RPC scanning # nmap -v -sR localhost nmap UDP scanning # nmap -v -O localhost nmap remote software version scanning # nmap -v -sV localhost
11 netcat
11.1 简单web服务器
web 查看系统状态 (TOP):
#!/bin/bash top -b -n 1 > /tmp/top.txt app = "nc -l 996" count=1; while [ count>0 ] do pn = `ps -wef|grep "${app}" |grep -v grep |grep " 1 "|wc -l` echo $pn if test $pn -lt 1 then top -b -n 1 >/tmp/top.txt nc -l 996 </tmp/top.txt fi done
12 nginx/php
$ sudo apt-get install nginx