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在以太网插入/拔出时执行脚本

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在以太网插入/拔出时执行脚本

我尝试在每次插入或拔出以太网电缆时自动执行自定义脚本。我使用的是 Ubuntu 15.10，到目前为止没有任何效果。首先，我尝试在 /etc/network/if-up.d/ 中创建一个脚本，更改其权限以便可以运行。该脚本是一个简单的 bash 脚本，只是为了确保它在我想要的确切时刻执行：

#!/bin/bash          
sudo echo "script Executed"  > testPlugIn.log

当我插入或拔出以太网电缆时它不起作用，但当我重新启动网络系统 sudo service networking restart 时它确实起作用但这不是我想要的。接下来我尝试创建一个 udev 规则。我在 /etc/udev/rules.d/ 中写入了以下规则：

KERNEL=="enp3s0",RUN+="/usr/bin/my_script"

它也不起作用。最后我发现我可以使用命令 inotifywait。为了测试它是否有效，我做了以下操作：

inotifywait -e modify /sys/class/net/enp4s0/carrier; echo 'change detected'

也不起作用。我插拔了以太网电缆，什么也没发生。你知道我做错了什么吗？

谢谢

答案1

以下是我“等待网络瘫痪然后执行某些操作”的方式：

#!/bin/bash
# Monitor for the net going down, Do The Next Thing (from a config file)
# to bring the net up. Implicit assumpition that The Next Thing fixes it
# may be a problem.
# Walt Sullivan

# Note: places where you may need to adjust things to match 
# your environment/taste are marked "#Adjust"

# determine my name
me=$0
me=${me##*/}

# my variables
debug=0             # set via --debug
verbose=0           # set via --verbose
original=""         # set the <config.file>
original_update=0       # time <config.file> was last modified
config="/var/tmp/${me}.$$.config" # my writable copy of config
result=""             # temporary use

# $ dpkg -S $(type -p nm-online)
# network-manager: /usr/bin/nm-online
# $ dpkg -S $(type -p ip)
# iproute2: /sbin/ip
# man ip-link;man ip-monitor;man ip-address;man 7 regex

# -h or --help or something's wrong in here
help () {
    echo "${me} [-h|--help] [-v|--verbose] <config.file> " >&2
    echo "" >&2
    echo "Monitor the wireless network, and when it goes down, Do The" >&2
    echo "Next Thing (as specified by the <config.file>), to bring" >&2
    echo "the wireless net up." >&2
    echo "" >&2
    echo "The <config.file> contains #comments, blank lines, AND" >&2
    echo "single line commands, of your choice, to correct the" >&2
    echo "wireless network down condition. The first command in the" >&2
    echo "<config.file> will be executed the first time the net goes" >&2
    echo "down (or if the net is down when ${me} begins), the second" >&2
    echo "command will be executed the next time the net goes down," >&2
    echo "and so forth, wrapping around at the end. The number of" >&2
    echo "single line commands in the <config.file> is unlimited." >&2
    exit 2
}

function flip () {
    # Return the first non-blank, non #comment line,
    # and move that line (and all preceeding blank and #comment
    # lines) to the end of (our copy of) the config file.
    #
    # ed pattern includes "/", but not "~" or "."
    #Adjust the ed pattern in both places and in countconfiglines
    ed --quiet "$config" <<EndOfEd
/^[A-Za-z0-9\/]/
1,.t$
1,/^[A-Za-z0-9\/]/d
wq
EndOfEd
}

function countconfiglines () {
    # return number of config file lines
    #Adjust must match the ed pattern in flip()
    configfile="$1"
    egrep --count '^[[:alnum:]/]' "$configfile"
    }

function up-to-date () {
    # updates configuration file if necessary
    new_update="$(/usr/bin/stat --format='%Y' $original )"
    if [[  "$new_update" -ne "$original_update" ]] ; then
    if [[ $(countconfiglines "$original") -eq 0  ]] ; then
        echo "Invalid configuration in $original" >&2
        exit 4
    else
        /bin/cp --force "$original" "$config"
        original_update="$new_update"
    fi
    fi
    }

function netstate () {
    # Return network state as "UP" or "DOWN"
    #Adjust how you decide net is UP/DOWN
    ip link show | egrep -q 'UP,LOWER_UP.* state UP'
    if [[ $? -eq 0 ]] ; then
    echo "UP"
    else
    echo "DOWN"
    fi
}

# Execution begins here

# parse the args with getopt, adapted from
# /usr/share/doc/util-linux/examples/getopt-parse.bash

TEMP=`getopt -o dhv --long debug,help,verbose \
     -n "${me}" -- "$@"`

if [[ $? != 0 ]] ; then echo "${me} --help for help." >&2 ; exit 1 ; fi

# Note the quotes around `$TEMP': they are essential!
eval set -- "$TEMP"

while true ; do
    case "$1" in
    -d|--debug) debug=1; shift;;
    -h|--help) help; shift;;
    -v|--verbose) verbose=1; shift;;
    --) shift; break;;
    *) echo "Internal error! ${me} --help for help";exit 1;;
    esac
done

# Did we get the <config.file>?
original="$1"
shift
[[ -z "$original" ]] && \
    (echo "Missing config file ${me} -h for help" >&2 ; exit 1)

# If there are more parameters, confusion exists in the mind of the caller
[[ "$#" -ne 0 ]] && help

[[ -r "$original" ]] || (echo "${me}:Cannot read $original" >&2
                exit 2)

if [[ $(countconfiglines "$original" ) -eq 0 ]] ; then
    echo "${me}:Invalid configuration in $original" >&2
    exit 4
else
    # watch for changes, record "%Y time of last modification,
    # seconds since Epoch"
    original_update="$(/usr/bin/stat --format='%Y' $original )"

    # make a writeable copy for our use, and clean it up at the end
    # unless $debug
    [[ $debug -ne 0 ]] || trap "/bin/rm -f $config" EXIT
    /bin/cp --force "$original" "$config"
fi

# if the net is down, Do The Next Thing right away
#Adjust: how you decide the net is up or down?
[[ "$(netstate)" = "DOWN" ]] && \
    ( result="$(flip)";
    [[ $verbose ]] && echo "$(date):$result" >&2; \
        eval "$result" )

# Wait for the net to go down, then Do The Next Thing
#Adjust find a better way to watch for net down 
ip monitor address | \
    egrep --line-buffered \
    '^Deleted [[:digit:]]+: [[:alnum:]]+[[:space:]]+inet[[:space:]].* scope global ' | \
    while read line ; do
    up-to-date
    result="$(flip)"
    [[ $verbose -eq 1 ]] && echo "$(date):$result" >&2
# Here is where "The Next Thing" is Done
    eval "$result"
done
# we never exit the while loop, until the world ends.
exit 0

答案2

如果您正在使用 NetworkManager，那么对网络状态变化做出反应的最佳方式就是将可执行文件放入其中/etc/NetworkManager/dispatcher.d/。

查看手册中的“调度脚本”部分：

调度脚本

NetworkManager/etc/NetworkManager/dispatcher.d将按字母顺序执行目录或子目录中的脚本以响应网络事件。[…]

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