Re: [Qemu-devel] [PATCH V2] Add stdio char device on windows

[Fabien Chouteau]

On 28/09/2011 11:57, Mars.cao wrote:
> On 09/27/2011 11:42 PM, Fabien Chouteau wrote:
>> Simple implementation of an stdio char device on Windows.
>>
>> Signed-off-by: Fabien Chouteau<address@hidden>
>> ---
>>   qemu-char.c |  199 
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>>   1 files changed, 197 insertions(+), 2 deletions(-)
>>
>> diff --git a/qemu-char.c b/qemu-char.c
>> index 09d2309..46acf1c 100644
>> --- a/qemu-char.c
>> +++ b/qemu-char.c
>> @@ -538,6 +538,9 @@ int send_all(int fd, const void *_buf, int len1)
>>   }
>>   #endif /* !_WIN32 */
>>
>> +#define STDIO_MAX_CLIENTS 1
>> +static int stdio_nb_clients;
> 
> Why change the default initial value (0) of stdio_nb_clients?
> Did you mean we should support multiple stdio clients?
> But I did not found any other stdio backend in the code.

I just removed the useless "0" initialization of this global variable.

>> +
>>   #ifndef _WIN32
>>
>>   typedef struct {
>> @@ -545,8 +548,6 @@ typedef struct {
>>       int max_size;
>>   } FDCharDriver;
>>
>> -#define STDIO_MAX_CLIENTS 1
>> -static int stdio_nb_clients = 0;
>>
>>   static int fd_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
>>   {
>> @@ -1451,6 +1452,8 @@ static int qemu_chr_open_pp(QemuOpts *opts, 
>> CharDriverState **_chr)
>>
>>   #else /* _WIN32 */
>>
>> +static CharDriverState *stdio_clients[STDIO_MAX_CLIENTS];
>> +
>>   typedef struct {
>>       int max_size;
>>       HANDLE hcom, hrecv, hsend;
>> @@ -1809,6 +1812,197 @@ static int qemu_chr_open_win_file_out(QemuOpts 
>> *opts, CharDriverState **_chr)
>>
>>       return qemu_chr_open_win_file(fd_out, _chr);
>>   }
>> +
>> +static int win_stdio_write(CharDriverState *chr, const uint8_t *buf, int 
>> len)
>> +{
>> +    HANDLE *hStdOut = GetStdHandle(STD_OUTPUT_HANDLE);
>> +    DWORD   dwSize;
>> +    int     len1;
>> +
>> +    len1 = len;
>> +
>> +    while (len1>  0) {
>> +        if (!WriteFile(hStdOut, buf, len1,&dwSize, NULL)) {
>> +            break;
>> +        }
>> +        buf  += dwSize;
>> +        len1 -= dwSize;
>> +    }
>> +
>> +    return len - len1;
>> +}
>> +
>> +static HANDLE *hStdIn;
>> +
>> +static void win_stdio_wait_func(void *opaque)
>> +{
>> +    CharDriverState *chr = opaque;
>> +    INPUT_RECORD     buf[4];
>> +    int              ret;
>> +    DWORD            dwSize;
>> +    int              i;
>> +
>> +    ret = ReadConsoleInput(hStdIn, buf, sizeof(buf)/sizeof(*buf),&dwSize);
>> +
>> +    if (!ret) {
>> +        /* Avoid error storm */
>> +        qemu_del_wait_object(hStdIn, NULL, NULL);
>> +        return;
>> +    }
>> +
>> +    for (i = 0; i<  dwSize; i++) {
>> +        KEY_EVENT_RECORD *kev =&buf[i].Event.KeyEvent;
>> +
>> +        if (buf[i].EventType == KEY_EVENT&&  kev->bKeyDown) {
>> +            int j;
>> +            if (kev->uChar.AsciiChar != 0) {
>> +                for (j = 0; j<  kev->wRepeatCount; j++)
>> +                    if (qemu_chr_be_can_write(chr)) {
>> +                        uint8_t c = kev->uChar.AsciiChar;
>> +                        qemu_chr_be_write(chr,&c, 1);
>> +                    }
>> +            }
>> +        }
>> +    }
>> +}
>> +
>> +static HANDLE  hInputReadyEvent;
>> +static HANDLE  hInputDoneEvent;
>> +static uint8_t win_stdio_buf;
>> +
>> +static DWORD WINAPI win_stdio_thread(LPVOID param)
>> +{
>> +    int   ret;
>> +    DWORD dwSize;
>> +
>> +    while (1) {
>> +
>> +        /* Wait for one byte */
>> +        ret = ReadFile(hStdIn,&win_stdio_buf, 1,&dwSize, NULL);
>> +
>> +        /* Exit in case of error, continue if nothing read */
>> +        if (!ret) {
>> +            break;
>> +        }
> 
> I think a qemu_del_wait_object() should be added before break.

I don't see why, can you explain?

>> +        if (!dwSize) {
>> +            continue;
>> +        }
>> +
>> +        /* Some terminal emulator returns \r\n for Enter, just pass \n */
>> +        if (win_stdio_buf == '\r') {
>> +            continue;
>> +        }
>> +
>> +        /* Signal the main thread and wait until the byte was eaten */
>> +        if (!SetEvent(hInputReadyEvent)) {
>> +            break;
>> +        }
>> +        if (WaitForSingleObject(hInputDoneEvent, INFINITE) != 
>> WAIT_OBJECT_0) {
>> +            break;
>> +        }
>> +    }
>> +
>> +    qemu_del_wait_object(hInputReadyEvent, NULL, NULL);
>> +    return 0;
>> +}
>> +
>> +static void win_stdio_thread_wait_func(void *opaque)
>> +{
>> +    CharDriverState *chr = opaque;
>> +
>> +    if (qemu_chr_be_can_write(chr)) {
>> +        qemu_chr_be_write(chr,&win_stdio_buf, 1);
>> +    }
>> +
>> +    SetEvent(hInputDoneEvent);
>> +}
>> +
>> +static void qemu_chr_set_echo_win_stdio(CharDriverState *chr, bool echo)
>> +{
>> +    DWORD dwMode = 0;
>> +
>> +    GetConsoleMode(hStdIn,&dwMode);
>> +
>> +    if (echo) {
>> +        SetConsoleMode(hStdIn, dwMode | ENABLE_ECHO_INPUT);
>> +    } else {
>> +        SetConsoleMode(hStdIn, dwMode&  ~ENABLE_ECHO_INPUT);
>> +    }
>> +}
>> +
>> +static int qemu_chr_open_win_stdio(QemuOpts         *opts,
>> +                                                CharDriverState **_chr)
>> +{
>> +    CharDriverState *chr;
>> +    DWORD            dwMode;
>> +    int              is_console = 0;
>> +
>> +    hStdIn = GetStdHandle(STD_INPUT_HANDLE);
>> +    if (hStdIn == INVALID_HANDLE_VALUE) {
>> +        fprintf(stderr, "cannot open stdio: invalid handle\n");
>> +        exit(1);
>> +    }
>> +
>> +    is_console = GetConsoleMode(hStdIn,&dwMode) != 0;
>> +
>> +    if (stdio_nb_clients>= STDIO_MAX_CLIENTS
>> +        || ((display_type != DT_NOGRAPHIC)&&  (stdio_nb_clients != 0))) {
>> +        return -EIO;
>> +    }
>> +
>> +    chr = g_malloc0(sizeof(CharDriverState));
>> +    if (!chr) {
>> +        return -ENOMEM;
>> +    }
> 
> I have not found any g_free for the CharDriverStart chr.

Good catch!

>> +
>> +    chr->chr_write = win_stdio_write;
>> +
>> +    if (stdio_nb_clients == 0) {
>> +        if (is_console) {
>> +            if (qemu_add_wait_object(hStdIn,
>> +                                     win_stdio_wait_func, chr)) {
>> +                fprintf(stderr, "qemu_add_wait_object: failed\n");
>> +            }
>> +        } else {
>> +            DWORD   dwId;
>> +            HANDLE *hInputThread;
>> +
>> +            hInputReadyEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
>> +            hInputDoneEvent  = CreateEvent(NULL, FALSE, FALSE, NULL);
>> +            hInputThread     = CreateThread(NULL, 0, win_stdio_thread,
>> +                                            chr, 0,&dwId);
> 
> I do not think it is a good idea to create 3 static global variant for the 2 
> events and the thread.
> Creating a new structure to contain the elements may be better.

I see your point but in this case the structure is just not necessary.

>> +
>> +            if (   hInputThread     == INVALID_HANDLE_VALUE
>> +                || hInputReadyEvent == INVALID_HANDLE_VALUE
>> +                || hInputDoneEvent  == INVALID_HANDLE_VALUE) {
>> +                fprintf(stderr, "cannot create stdio thread or event\n");
>> +                exit(1);
>> +            }
>> +            if (qemu_add_wait_object(hInputReadyEvent,
>> +                                     win_stdio_thread_wait_func, chr)) {
>> +                fprintf(stderr, "qemu_add_wait_object: failed\n");
>> +            }
>> +        }
>> +    }
>> +
>> +    dwMode |= ENABLE_LINE_INPUT;
>> +
>> +    stdio_clients[stdio_nb_clients++] = chr;
>> +    if (stdio_nb_clients == 1&&  is_console) {
>> +        /* set the terminal in raw mode */
>> +        /* ENABLE_QUICK_EDIT_MODE | ENABLE_EXTENDED_FLAGS */
>> +        dwMode |= ENABLE_PROCESSED_INPUT;
>> +    }
>> +
>> +    SetConsoleMode(hStdIn, dwMode);
>> +
>> +    chr->chr_set_echo = qemu_chr_set_echo_win_stdio;
>> +    qemu_chr_fe_set_echo(chr, false);
>> +
>> +    *_chr = chr;
>> +
>> +    return 0;
>> +}
>>   #endif /* !_WIN32 */
>>
>>   /***********************************************************/
>> @@ -2519,6 +2713,7 @@ static const struct {
>>       { .name = "pipe",      .open = qemu_chr_open_win_pipe },
>>       { .name = "console",   .open = qemu_chr_open_win_con },
>>       { .name = "serial",    .open = qemu_chr_open_win },
>> +    { .name = "stdio",     .open = qemu_chr_open_win_stdio },
>>   #else
>>       { .name = "file",      .open = qemu_chr_open_file_out },
>>       { .name = "pipe",      .open = qemu_chr_open_pipe },
> 
> I am a new rookie in qemu-devel,so forgive my misunderstanding.
> I will test your patch in future 2 days.

Please wait for v3.

Thanks for the review!

-- 
Fabien Chouteau