Copy host env to container for env/envfile option

[liubin]

Add a function to process env/envfile specified by users and set value for env with no value has been set.

Fixes: #1487

Signed-off-by: bin liu liubin0329@gmail.com

New behaiver with this patch:

For host envs:

root@master:~# export X=abc
root@master:~# docker run --rm --env X alpine printenv X
abc
root@master:~# docker run --rm --env X=23 alpine printenv X
23
root@master:~# docker run --rm --env X= alpine printenv X

root@master:~# nerdctl run --rm --net=none --env X alpine printenv X
abc
root@master:~# nerdctl run --rm --net=none --env X=23 alpine printenv X
23
root@master:~# nerdctl run --rm --net=none --env X= alpine printenv X

For envs not in host:

root@master:~# unset X
root@master:~# docker run --rm --env X alpine printenv X
root@master:~# docker run --rm --env X=23 alpine printenv X
23
root@master:~# docker run --rm --env X= alpine printenv X

root@master:~# nerdctl run --rm --net=none --env X alpine printenv X
root@master:~# nerdctl run --rm --net=none --env X=23 alpine printenv X
23
root@master:~# nerdctl run --rm --net=none --env X= alpine printenv X

[AkihiroSuda]

Thanks

[AkihiroSuda]

CI failing

=== CONT  TestRunEnv
    run_test.go:193: assertion failed: error is not nil: got bad GARPLY: ALLUSERSPROFILE=C:\ProgramData
        APPDATA=C:\Users\ContainerAdministrator\AppData\Roaming
        BAR=bar1 bar2
        CommonProgramFiles=C:\Program Files\Common Files
        CommonProgramFiles(x86)=C:\Program Files (x86)\Common Files
        CommonProgramW6432=C:\Program Files\Common Files
        COMPUTERNAME=FC1E0F5CF954
        ComSpec=C:\Windows\system32\cmd.exe
        CORGE=corge-value-in-host
        DriverData=C:\Windows\System32\Drivers\DriverData
        FOO=foo1,foo2
        GRAULT=grault_key=grault_value
        LOCALAPPDATA=C:\Users\ContainerAdministrator\AppData\Local
        NUMBER_OF_PROCESSORS=2
        OS=Windows_NT
        Path=C:\dig\;C:\bin;C:\curl;C:\Windows\System32;C:\Windows;C:\Program Files\PowerShell;
        PATHEXT=.COM;.EXE;.BAT;.CMD
        PROCESSOR_ARCHITECTURE=AMD64
        PROCESSOR_IDENTIFIER=AMD64 Family 25 Model 1 Stepping 0, AuthenticAMD
        PROCESSOR_LEVEL=25
        PROCESSOR_REVISION=0100
        ProgramData=C:\ProgramData
        ProgramFiles=C:\Program Files
        ProgramFiles(x86)=C:\Program Files (x86)
        ProgramW6432=C:\Program Files
        PROMPT=$P$G
        PSCORE=C:\Program Files\PowerShell\pwsh.exe
        PSModuleAnalysisCachePath=C:\Users\ContainerAdministrator\AppData\Local\Microsoft\Windows\PowerShell\docker\ModuleAnalysisCache
        PUBLIC=C:\Users\Public
        QUUX=quux2
        SystemDrive=C:
        SystemRoot=C:\Windows
        TEMP=C:\Windows\TEMP
        TMP=C:\Windows\TEMP
        USERDOMAIN=User Manager
        USERNAME=ContainerAdministrator
        USERPROFILE=C:\Users\ContainerAdministrator
        windir=C:\Windows
--- FAIL: TestRunEnv (1.03s)

https://cirrus-ci.com/task/6507949194477568

[liubin]

@AkihiroSuda I think I have fixed the issue in Windows.