fix(xfreerdp): try --list-kbd as last resort

[yedayak]

This is the only option that seems to work in xfreerdp 1.0.2, which is what comes with ubuntu 14.04.

Follow up to #1373

[yedayak]

🟢

[akinomyoga]

OK, but is FreeRDP/FreeRDP@9295838 the relevant commit? I'm not sure how this change affected the actual behavior of the command.

[akinomyoga]

I guess FreeRDP/FreeRDP@30275e7 is the commit, but I'm now unsure whether dropping the support for the POSIX style --kbd-list (in favor of /kbd-list) was the intended change. Although /kbd-list and --kbd-list were deprecated after that, valid options such as /list:timezones and --list timezones are still affected. There don't seem to be any mentions of this change in official documents.

First of all, the core part of the command-line parsing in FreeRDP seems to be performed by CommandLineParseArgumentsA. When COMMAND_LINE_SIGIL_DOUBLE_DASH (0x00000008) is specified to the flag parameter, it processes the double-dash syntax.

The current upstream FreeRDP still seems to accept both Windows and POSIX forms of the command options basically. The command-line parsing is performed by freerdp_client_settings_parse_command_line_arguments_int:

1. This function calls another function freerdp_client_detect_command_line, where parsing of both the windows and posix styles of options is attempted. It even says the POSIX style is default.
   • The function freerdp_detect_posix_style_command_line_syntax called by freerdp_client_detect_command_line uses CommandLineParseArgumentsA with COMMAND_LINE_SIGIL_DOUBLE_DASH, so it parses the double-dash forms of the command-line options.
2. Then, if freerdp_client_detect_command_line doesn't detect any compatibility issue, it finally calls CommandLineParseArgumentsA with flags determined by freerdp_client_detect_command_line.

The problem is that in freerdp_client_settings_command_line_status_print_ex, before processing status-report command-line options, CommandLineParseArgumentsA is called again with a fixed flags (0x112) (which doesn't include COMMAND_LINE_SIGIL_DOUBLE_DASH). This extra command-parsing was introduced by the mentioned commit, which is associated with PR FreeRDP/FreeRDP#5707, a fix for FreeRDP/FreeRDP#5695. However, they don't seem to have discussed anything about the change in the Windows/POSIX styles of the command-line parsing.