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Re: [Qemu-trivial] [PATCH] Keep pty slave file descriptor open until the
From: |
Michael Tokarev |
Subject: |
Re: [Qemu-trivial] [PATCH] Keep pty slave file descriptor open until the master is closed |
Date: |
Mon, 11 Jan 2016 11:33:58 +0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Icedove/38.5.0 |
11.12.2015 14:29, Ashley Jonathan wrote:
> I have experienced a minor difficulty using QEMU with the "-serial pty"
> option:
>
> If a process opens the slave pts device, writes data to it, then immediately
> closes it, the data doesn't reliably get delivered to the emulated serial
> port. This seems to be because a read of the master pty device returns EIO on
> Linux if no process has the pts device open, even when data is waiting "in
> the pipe".
>
> A fix seems to be for QEMU to keep the pts file descriptor open until the pty
> is closed, as per the below patch.
The patch looks fine, so
Reviewed-by: Michael Tokarev <address@hidden>
but I'd love to have an ACK from the maintainer about this one,
or for it to pick it up.
Thanks,
/mjt
> ---
> qemu-char.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/qemu-char.c b/qemu-char.c
> index 2969c44..ed03ba0 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -1198,6 +1198,7 @@ typedef struct {
> int connected;
> guint timer_tag;
> guint open_tag;
> + int slave_fd;
> } PtyCharDriver;
>
> static void pty_chr_update_read_handler_locked(CharDriverState *chr);
> @@ -1373,6 +1374,7 @@ static void pty_chr_close(struct CharDriverState *chr)
>
> qemu_mutex_lock(&chr->chr_write_lock);
> pty_chr_state(chr, 0);
> + close(s->slave_fd);
> fd = g_io_channel_unix_get_fd(s->fd);
> g_io_channel_unref(s->fd);
> close(fd);
> @@ -1401,7 +1403,6 @@ static CharDriverState *qemu_chr_open_pty(const char
> *id,
> return NULL;
> }
>
> - close(slave_fd);
> qemu_set_nonblock(master_fd);
>
> chr = qemu_chr_alloc();
> @@ -1422,6 +1423,7 @@ static CharDriverState *qemu_chr_open_pty(const char
> *id,
> chr->explicit_be_open = true;
>
> s->fd = io_channel_from_fd(master_fd);
> + s->slave_fd = slave_fd;
> s->timer_tag = 0;
>
> return chr;
>
- Re: [Qemu-trivial] [PATCH] Keep pty slave file descriptor open until the master is closed,
Michael Tokarev <=