RFR: 8337506: Disable "best-fit" mapping on Windows command line

[Naoto Sato]

On Fri, 2 Aug 2024 09:30:56 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> Fixing the Java launcher's command line argument parsing issue on Windows. The Java launcher on Windows has been using `GetCommandLineA()` to obtain arguments, which by default does "best-fit" mapping when the arguments are converted to ANSI code page encoding. By disabling this "best-fit" mapping, the launcher's parsing works as expected. A corresponding CSR has been drafted for the behavioral change.
>
> src/java.base/share/native/launcher/main.c line 121:
> 
>> 119:         wcCmdline, -1, NULL, 0, NULL, NULL);
>> 120:     LPSTR mbCmdline = JLI_MemAlloc(mbSize);
>> 121:     if (WideCharToMultiByte(CP_ACP, WC_NO_BEST_FIT_CHARS | WC_COMPOSITECHECK | WC_DEFAULTCHAR,
> 
> I think this looks okay but will need to handle GetCommandLineW, WideCharToMultiByte, or JLI_MemAlloc failing.

IIUC, all errors should be handled with the proposed patch. On error with JLI_MemAlloc and WideCharToMultiByte, the process exits with `exit(1)`. As to `GetCommandLineW()`, there is no description of error in the MS document (https://learn.microsoft.com/en-us/windows/win32/api/processenv/nf-processenv-getcommandlinew), so I suppose no error handling on our side is needed.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20428#discussion_r1702102957