Unexpectedly changed the output code page when calling the ssh, ssh-keygen, scp, sftp command.

[kemaruya]

Prerequisites

• Write a descriptive title.
• Make sure you are able to repro it on the latest version
• Search the existing issues.

Steps to reproduce

Open command prompt and just run scp, sftp, ssh or ssh-keygen command.

Expected behavior

Keep previews output codepage between before execute scp, sftp, ssh or ssh-keygen command.

----
Microsoft Windows [Version 10.0.20348.169]
(c) Microsoft Corporation. All rights reserved.
 
C:\Users\Administrator>chcp
現在のコード ページ: 932 << Output Language is Japanese (CP932)
 
C:\Users\Administrator>ssh
usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]
           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]
           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]
           [-i identity_file] [-J [user@]host[:port]] [-L address]
           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]
           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]
           [-w local_tun[:remote_tun]] destination [command]
 
C:\Users\Administrator>chcp
現在のコード ページ: 932 << Output Language is still Japanese (CP932)
 
C:\Users\Administrator>

Actual behavior

The output codepage has been changed to UTF8 (65001) after execute scp, sftp, ssh or ssh-keygen command.

----
Microsoft Windows [Version 10.0.20348.169]
(c) Microsoft Corporation. All rights reserved.
 
C:\Users\Administrator>chcp
現在のコード ページ: 932 << Output Language is Japanese (CP932)
 
C:\Users\Administrator>ssh
usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface]
           [-b bind_address] [-c cipher_spec] [-D [bind_address:]port]
           [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11]
           [-i identity_file] [-J [user@]host[:port]] [-L address]
           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]
           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]
           [-w local_tun[:remote_tun]] destination [command]
 
C:\Users\Administrator>chcp
Active code page: 932 << Output Language has been changed to UTF8 (CP65001)
 
C:\Users\Administrator>

Error details

No response

Environment data

Name                           Value
----                           -----
PSVersion                      5.1.20348.1
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.20348.1
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Version

9.1.0.0

Visuals

No response

[kemaruya]

The issue was caused by the following pull request.
Allow Console Output In UTF-8 by NoMoreFood · Pull Request #378 · PowerShell/openssh-portable (github.com)

[mgkuhn]

@NoMoreFood I first wondered if your calling SetConsoleOutputCP() (without saving the previous state first with GetConsoleOutputCP) in contrib/win32/win32compat/win32-utf8.c:msetlocale() isn't redundant, given that there also has been code to do all that in contrib/win32/win32compat/console.c:ConEnterRawMode() since PowerShell/openssh-portable@84e87be which does save and restore the prior state?

But then I realized may be not, as msetlocale() also gets called not only in ssh, but also in scp, sftp, ssh-keygen, which probably don't open a raw-mode console. I suspect msetlocale(), which gets called earlier, should query with GetConsoleOutputCP the prior state. It can't return that state, such that the caller could restore the prior state, e.g. in a function registered with atexit(), because the original utf8.c:msetlocale() is a wrapper around setlocale() that doesn't save any state, because on Unix setlocale doesn't change any state outside the current process, unlike SetConsoleOutputCP, which does affect the console state beyond the lifetime of the current process. So perhaps registering an atexit() function to restore the CP state from within contrib/win32/win32compat/win32-utf8.c:msetlocale() is a better thing to do here?

[kemaruya]

I wrote a workaround to address the #2027 issue.
The compilation was successful and confirmed that the event could be avoided.
PowerShell/openssh-portable#666