[Spice-devel] [PATCH 1/2 v3] Attempt to manage redirection in a way similar to Unix

[Fabiano Fidêncio]

On Fri, Apr 29, 2016 at 4:09 PM, Frediano Ziglio <fziglio at redhat.com> wrote:
> This patch allows remote-viewer to redirect output/error streams to
> files.
> Also if launched from a console program (for instance from the command
> prompt) you are able to see output from the console where you launch
> the program.
> This allow to launch the program with a syntax like
>   > remote-viewer.exe --debug > log.txt 2>&1
> or simply
>   > remote-viewer.exe --debug
>
> Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> ---
>  src/virt-viewer-util.c | 36 +++++++++++++++++++++++++++++-------
>  1 file changed, 29 insertions(+), 7 deletions(-)
>
> Changes from previous version:
> - fixed different redirection combinations;
> - tested on Windows XP, 7 and 10.
>
> diff --git a/src/virt-viewer-util.c b/src/virt-viewer-util.c
> index 8cf52ec..ebe039c 100644
> --- a/src/virt-viewer-util.c
> +++ b/src/virt-viewer-util.c
> @@ -253,6 +253,17 @@ static void log_handler(const gchar *log_domain,
>      g_log_default_handler(log_domain, log_level, message, unused_data);
>  }
>
> +#ifdef G_OS_WIN32
> +static BOOL is_handle_valid(HANDLE h)
> +{
> +    if (h == INVALID_HANDLE_VALUE || h == NULL)
> +        return FALSE;
> +
> +    DWORD flags;
> +    return GetHandleInformation(h, &flags);
> +}
> +#endif
> +
>  void virt_viewer_util_init(const char *appname)
>  {
>  #ifdef G_OS_WIN32
> @@ -265,13 +276,24 @@ void virt_viewer_util_init(const char *appname)
>       */
>      CreateMutexA(0, 0, "VirtViewerMutex");
>
> -    if (AttachConsole(ATTACH_PARENT_PROCESS) != 0) {
> -        freopen("CONIN$", "r", stdin);
> -        freopen("CONOUT$", "w", stdout);
> -        freopen("CONOUT$", "w", stderr);
> -        dup2(fileno(stdin), STDIN_FILENO);
> -        dup2(fileno(stdout), STDOUT_FILENO);
> -        dup2(fileno(stderr), STDERR_FILENO);
> +    /* Get redirection from parent */
> +    BOOL out_valid = is_handle_valid(GetStdHandle(STD_OUTPUT_HANDLE));
> +    BOOL err_valid = is_handle_valid(GetStdHandle(STD_ERROR_HANDLE));
> +
> +    /*
> +     * If not all output are redirected try to redirect to parent console.
> +     * If parent has no console (for instance as launched from GUI) just
> +     * rely on default (no output).
> +     */
> +    if ((!out_valid || !err_valid) && AttachConsole(ATTACH_PARENT_PROCESS)) {
> +        if (!out_valid) {
> +            freopen("CONOUT$", "w", stdout);
> +            dup2(fileno(stdout), STDOUT_FILENO);
> +        }
> +        if (!err_valid) {
> +            freopen("CONOUT$", "w", stderr);
> +            dup2(fileno(stderr), STDERR_FILENO);
> +        }
>      }
>
>      /* Disable input method handling so that the Zenkaku_Hankaku can be passed
> --
> 2.5.5
>
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Acked-by: Fabiano Fidêncio <fidencio at redhat.com>
-- 
Fabiano Fidêncio