[Spice-devel] [PATCH] Add utility to help redirecting output from remote-viewer/virt-viewer

Fabiano Fidêncio fidencio at redhat.com
Wed Mar 2 16:48:22 UTC 2016


Frediano,

On Tue, Mar 1, 2016 at 6:12 PM, Frediano Ziglio <fziglio at redhat.com> wrote:
>
>>
>> Hi
>>
>> ----- Original Message -----
>> > These utility use some trick to use console even if they are GUI
>> > application (not supposed to have a console by default).
>> > This make output redirection harder as output by default will tend
>> > to go to console of parent process instead of using redirected output.
>> > This utility avoid remote-viewer/virt-viewer to see the calling process
>> > console keeping the wanted redirection.
>>
>> This looks like it should replace windows-cmdline-wrapper altogether.
>>
>
> Really? I though the two utility were written for different purposes.
> I though your utility was a complement of the AttachConsole in the executable
> so the executable detect them and can provide some control/feedback using
> the console.
>
> If it's just redirect to console if parent has a console or to file if we
> want to redirect to file probably we can find a solution in
> virt-viewer/remote-viewer that satisfy both requirements.

Tested you program on a Windows machine. Seems to work as expected, so
I'd remove the current wndows-command-line-wrapper.c in favour of
yours.

One question, can you teach you program to do nothing when no redirect
is needed?
I mean, if no " > log.txt", then just print everything on the
stdout/stderr as usual.

Please, after addressing Marc-André comments about Unicode, can you
submit a v2, but then to the virt-tools-list? It's a solution for
virt-viewer, so it's better if we do the review there.

>
> Frediano
>
>> >
>> > Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
>> > ---
>> >  src/Makefile.am               |  4 ++
>> >  src/output-redirect-wrapper.c | 92
>> >  +++++++++++++++++++++++++++++++++++++++++++
>> >  2 files changed, 96 insertions(+)
>> >  create mode 100644 src/output-redirect-wrapper.c
>> >
>> > diff --git a/src/Makefile.am b/src/Makefile.am
>> > index e76f5bc..01b9bc8 100644
>> > --- a/src/Makefile.am
>> > +++ b/src/Makefile.am
>> > @@ -155,6 +155,10 @@ bin_PROGRAMS += windows-cmdline-wrapper
>> >  windows_cmdline_wrapper_SOURCES = windows-cmdline-wrapper.c
>> >  windows_cmdline_wrapper_LDFLAGS = -lpsapi
>> >
>> > +bin_PROGRAMS += output-redirect-wrapper
>> > +output_redirect_wrapper_SOURCES  = output-redirect-wrapper.c
>> > +output_redirect_wrapper_CPPFLAGS = -DUNICODE -D_UNICODE
>> > +
>> >  virt-viewer_rc.$(OBJEXT): $(VIRT_VIEWER_RES) $(ICONDIR)/virt-viewer.ico
>> >     $(AM_V_GEN)$(WINDRES)                           \
>> >             -DICONDIR='\"$(ICONDIR)\"'              \
>> > diff --git a/src/output-redirect-wrapper.c b/src/output-redirect-wrapper.c
>> > new file mode 100644
>> > index 0000000..ed807bb
>> > --- /dev/null
>> > +++ b/src/output-redirect-wrapper.c
>> > @@ -0,0 +1,92 @@
>> > +/*
>> > + * Windows cmd: a command line wrapper for GUI applications
>> > + *
>> > + * Copyright (C) 2012-2016 Red Hat, Inc.
>> > + *
>> > + * This program is free software; you can redistribute it and/or modify
>> > + * it under the terms of the GNU General Public License as published by
>> > + * the Free Software Foundation; either version 2 of the License, or
>> > + * (at your option) any later version.
>> > + *
>> > + * This program is distributed in the hope that it will be useful,
>> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> > + * GNU General Public License for more details.
>> > + *
>> > + * You should have received a copy of the GNU General Public License
>> > + * along with this program; if not, write to the Free Software
>> > + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
>> > USA
>> > + *
>> > + * Usage:
>> > + * This wrapper allows to redirect output even if your application
>> > + * tries to redirect its output to console.
>> > + *
>> > + * For instance you can use from console with a syntax like
>> > + *
>> > + *   output-redirect-wrapper remote-viewer.exe --debug > log.txt
>> > + *
>> > + * Based on Marc-André Lureau wrappers
>> > + */
>> > +
>> > +#include <windows.h>
>> > +#include <stdio.h>
>> > +#include <string.h>
>> > +#include <tchar.h>
>> > +
>> > +int main(void)
>> > +{
>> > +    STARTUPINFO si = { 0, };
>> > +    PROCESS_INFORMATION pi = { 0, };
>> > +
>> > +    // pass same input/output handles
>> > +    si.cb = sizeof(si);
>> > +    si.dwFlags = STARTF_USESTDHANDLES;
>> > +    si.hStdInput  = GetStdHandle(STD_INPUT_HANDLE);
>> > +    // redirect all to single output
>> > +    si.hStdError = si.hStdOutput = GetStdHandle(STD_OUTPUT_HANDLE);
>> > +    SetHandleInformation(si.hStdInput,  HANDLE_FLAG_INHERIT,
>> > HANDLE_FLAG_INHERIT);
>> > +    SetHandleInformation(si.hStdOutput, HANDLE_FLAG_INHERIT,
>> > HANDLE_FLAG_INHERIT);
>> > +
>> > +    // parse command line, strip executable
>> > +    TCHAR *cmdline = GetCommandLine();
>> > +    cmdline += _tcsspn(cmdline, _T(" \t\v"));
>> > +    TCHAR *end = _tcsstr(cmdline, cmdline[0] == _T('\"') ? _T("\" ") :
>> > _T("
>> > "));
>> > +    if (!end) {
>> > +        fprintf(stderr, "Please pass executable to call\n");
>> > +        return 1;
>> > +    }
>> > +    cmdline = end + 1;
>> > +    cmdline += _tcsspn(cmdline, _T(" \t\v"));
>> > +
>> > +    // release console so program launched do not redirect to it
>> > +    FreeConsole();
>> > +
>> > +    if (!CreateProcess(NULL,
>> > +                       cmdline,
>> > +                       NULL,           // Process handle not inheritable
>> > +                       NULL,           // Thread handle not inheritable
>> > +                       TRUE,           // Handle inheritance
>> > +                       0,              // No creation flags
>> > +                       NULL,           // Use parent's environment block
>> > +                       NULL,           // Use parent's starting directory
>> > +                       &si,
>> > +                       &pi)) {
>> > +        fprintf(stderr, "CreateProcess failed (%ld).\n", (long)
>> > GetLastError());
>> > +        return 1;
>> > +    }
>> > +    // Close unneeded handle
>> > +    CloseHandle(pi.hThread);
>> > +
>> > +    // Wait until child process exits.
>> > +    WaitForSingleObject(pi.hProcess, INFINITE);
>> > +
>> > +    DWORD exit_code;
>> > +    GetExitCodeProcess(pi.hProcess, &exit_code);
>> > +
>> > +    // Close process handle
>> > +    CloseHandle(pi.hProcess);
>> > +
>> > +    // return same output of application
>> > +    ExitProcess(exit_code);
>> > +    return 0;
>> > +}
>> > --
>> > 2.5.0
>> >
>> > _______________________________________________
>> > Spice-devel mailing list
>> > Spice-devel at lists.freedesktop.org
>> > https://lists.freedesktop.org/mailman/listinfo/spice-devel
>> >
>>
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Best Regards,
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