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From: Jason Andryuk <jandryuk@gmail.com>
To: "Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Julien Grall <julien@xen.org>, Wei Liu <wl@xen.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	George Dunlap <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [Xen-devel] [PATCH v4 11/16] tools: add simple vchan-socket-proxy
Date: Tue, 21 Jan 2020 14:43:03 -0500
Message-ID: <CAKf6xpuQ1iggu6Lz8bcAWpGL732bXf3qwO9HYSd+8ScsNN2wnA@mail.gmail.com> (raw)
In-Reply-To: <ce51dd78fd7aa0856d160b2d94c82f68dd4e7056.1579055705.git-series.marmarek@invisiblethingslab.com>

On Tue, Jan 14, 2020 at 9:42 PM Marek Marczykowski-Górecki
<marmarek@invisiblethingslab.com> wrote:
>
> Add a simple proxy for tunneling socket connection over vchan. This is
> based on existing vchan-node* applications, but extended with socket
> support. vchan-socket-proxy serves both as a client and as a server,
> depending on parameters. It can be used to transparently communicate
> with an application in another domian that normally expose UNIX socket
> interface. Specifically, it's written to communicate with qemu running
> within stubdom.
>
> Server mode listens for vchan connections and when one is opened,
> connects to a pointed UNIX socket.  Client mode listens on UNIX
> socket and when someone connects, opens a vchan connection.  Only
> a single connection at a time is supported.
>
> Additionally, socket can be provided as a number - in which case it's
> interpreted as already open FD (in case of UNIX listening socket -
> listen() needs to be already called). Or "-" meaning stdin/stdout - in
> which case it is reduced to vchan-node2 functionality.
>
> Example usage:
>
> 1. (in dom0) vchan-socket-proxy --mode=client <DOMID>
>     /local/domain/<DOMID>/data/vchan/1234 /run/qemu.(DOMID)
>
> 2. (in DOMID) vchan-socket-proxy --mode=server 0
>    /local/domain/<DOMID>/data/vchan/1234 /run/qemu.(DOMID)
>
> This will listen on /run/qemu.(DOMID) in dom0 and whenever connection is
> made, it will connect to DOMID, where server process will connect to
> /run/qemu.(DOMID) there. When client disconnects, vchan connection is
> terminated and server vchan-socket-proxy process also disconnects from
> qemu.
>
> Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
> ---

Looks good.  A few typos and string updates below.

Reviewed-by: Jason Andryuk <jandryuk@gmail.com>

<snip>

> diff --git a/tools/libvchan/vchan-socket-proxy.c b/tools/libvchan/vchan-socket-proxy.c
> new file mode 100644
> index 0000000..6b4ae09
> --- /dev/null
> +++ b/tools/libvchan/vchan-socket-proxy.c

<snip>

> +static void usage(char** argv)
> +{
> +    fprintf(stderr, "usage:\n"
> +        "\t%s [options] domainid nodepath [socket-path|file-no|-]\n"
> +        "\n"
> +        "options:\n"
> +        "\t-m, --mode=client|server - vchan connection mode\n"

Add "(client by default)"?

> +        "\t-m, --state-path=path - xenstore path where write \"running\" to at startup\n"

-s is the short option here.

> +        "\t-v, --verbose - verbose logging\n"
> +        "\n"
> +        "client: client of a vchan connection, fourth parameter can be:\n"
> +        "\tsocket-path: listen on a UNIX socket at this path and connect to vchan\n"
> +        "\t  whenever new connection is accepted;\n"
> +        "\t  handle multiple _subsequent_ connections, until terminated\n"
> +        "\tfile-no: except open FD of a socket in listen mode; otherwise similar to socket-path\n"

Many of these lines are long and hard to read on 80 column terminals.

> +        "\t-: open vchan connection immediately and pass the data from stdin/stdout;\n"
> +        "\t  terminate when vchan connection is closed\n"
> +        "server: server of a vchan connection, fourth parameter can be:\n"
> +        "\tsocket-path: connect to this UNIX socket when new vchan connection is accepted\n"
> +        "\t  handle multiple _subsequent_ connections, until terminated\n"
> +        "\tfile-no: pass data to/from this FD; terminate when vchan connection is closed\n"
> +        "\t-: pass data to/from stdin/stdout; terminatate when vchan connection is closed\n",

s/terminatate/terminate/

> +        argv[0]);
> +    exit(1);
> +}
> +
> +#define BUFSIZE 8192
> +char inbuf[BUFSIZE];
> +char outbuf[BUFSIZE];
> +int insiz = 0;
> +int outsiz = 0;
> +int verbose = 0;
> +
> +static void vchan_wr(struct libxenvchan *ctrl) {
> +    int ret;
> +
> +    if (!insiz)
> +        return;
> +    ret = libxenvchan_write(ctrl, inbuf, insiz);
> +    if (ret < 0) {
> +        fprintf(stderr, "vchan write failed\n");
> +        exit(1);
> +    }
> +    if (verbose)
> +        fprintf(stderr, "written %d bytes to vchan\n", ret);

s/written/wrote/

> +    if (ret > 0) {
> +        insiz -= ret;
> +        memmove(inbuf, inbuf + ret, insiz);
> +    }
> +}
> +

<snip>

> +
> +int data_loop(struct libxenvchan *ctrl, int input_fd, int output_fd)
> +{
> +    int ret;
> +    int libxenvchan_fd;
> +    int max_fd;
> +
> +    libxenvchan_fd = libxenvchan_fd_for_select(ctrl);
> +    for (;;) {
> +        fd_set rfds;
> +        fd_set wfds;
> +        FD_ZERO(&rfds);
> +        FD_ZERO(&wfds);
> +
> +        max_fd = -1;
> +        if (input_fd != -1 && insiz != BUFSIZE) {
> +            FD_SET(input_fd, &rfds);
> +            if (input_fd > max_fd)
> +                max_fd = input_fd;
> +        }
> +        if (output_fd != -1 && outsiz) {
> +            FD_SET(output_fd, &wfds);
> +            if (output_fd > max_fd)
> +                max_fd = output_fd;
> +        }
> +        FD_SET(libxenvchan_fd, &rfds);
> +        if (libxenvchan_fd > max_fd)
> +            max_fd = libxenvchan_fd;
> +        ret = select(max_fd + 1, &rfds, &wfds, NULL, NULL);
> +        if (ret < 0) {
> +            perror("select");
> +            exit(1);
> +        }
> +        if (FD_ISSET(libxenvchan_fd, &rfds)) {
> +            libxenvchan_wait(ctrl);
> +            if (!libxenvchan_is_open(ctrl)) {
> +                if (verbose)
> +                    fprintf(stderr, "vchan client disconnected\n");
> +                while (outsiz)
> +                    socket_wr(output_fd);
> +                close(output_fd);
> +                close(input_fd);
> +                discard_buffers(ctrl);
> +                break;
> +            }
> +            vchan_wr(ctrl);
> +        }
> +
> +        /* socket_fd guaranteed to be != -1 */

Old comment?

> +        if (FD_ISSET(input_fd, &rfds)) {
> +            ret = read(input_fd, inbuf + insiz, BUFSIZE - insiz);
> +            if (ret < 0 && errno != EAGAIN)
> +                exit(1);
> +            if (verbose)
> +                fprintf(stderr, "from-unix: %.*s\n", ret, inbuf + insiz);
> +            if (ret == 0) {
> +                /* EOF on socket, write everything in the buffer and close the
> +                 * socket */

Change to socket to input_fd?

> +                while (insiz) {
> +                    vchan_wr(ctrl);
> +                    libxenvchan_wait(ctrl);
> +                }
> +                close(input_fd);
> +                input_fd = -1;
> +                /* TODO: maybe signal the vchan client somehow? */
> +                break;
> +            }
> +            if (ret)
> +                insiz += ret;
> +            vchan_wr(ctrl);
> +        }
> +        if (FD_ISSET(output_fd, &wfds))
> +            socket_wr(output_fd);
> +        while (libxenvchan_data_ready(ctrl) && outsiz < BUFSIZE) {
> +            ret = libxenvchan_read(ctrl, outbuf + outsiz, BUFSIZE - outsiz);
> +            if (ret < 0)
> +                exit(1);
> +            if (verbose)
> +                fprintf(stderr, "from-vchan: %.*s\n", ret, outbuf + outsiz);
> +            outsiz += ret;
> +            socket_wr(output_fd);
> +        }
> +    }
> +    return 0;
> +}
> +

<snip>

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  parent reply index

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-15  2:39 [Xen-devel] [PATCH v4 00/16] Add support for qemu-xen runnning in a Linux-based stubdomain Marek Marczykowski-Górecki
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 01/16] Document ioemu MiniOS stubdomain protocol Marek Marczykowski-Górecki
2020-01-20 18:30   ` Jason Andryuk
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 02/16] Document ioemu Linux " Marek Marczykowski-Górecki
2020-01-20 18:54   ` Jason Andryuk
2020-01-21 21:08     ` Marek Marczykowski-Górecki
2020-01-22 14:04       ` Jason Andryuk
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 03/16] libxl: fix qemu-trad cmdline for no sdl/vnc case Marek Marczykowski-Górecki
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 04/16] libxl: Allow running qemu-xen in stubdomain Marek Marczykowski-Górecki
2020-01-20 18:56   ` Jason Andryuk
2020-01-21 21:12     ` Marek Marczykowski-Górecki
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 05/16] libxl: Handle Linux stubdomain specific QEMU options Marek Marczykowski-Górecki
2020-01-20 19:24   ` Jason Andryuk
2020-01-21 21:18     ` Marek Marczykowski-Górecki
2020-01-22 14:25       ` Jason Andryuk
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 06/16] libxl: write qemu arguments into separate xenstore keys Marek Marczykowski-Górecki
2020-01-20 19:36   ` Jason Andryuk
2020-01-21 21:19     ` Marek Marczykowski-Górecki
2020-01-22 14:39       ` Jason Andryuk
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 07/16] xl: add stubdomain related options to xl config parser Marek Marczykowski-Górecki
2020-01-20 19:41   ` Jason Andryuk
2020-01-21 21:22     ` Marek Marczykowski-Górecki
2020-01-22 14:39       ` Jason Andryuk
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 08/16] tools/libvchan: notify server when client is connected Marek Marczykowski-Górecki
2020-01-20 19:44   ` Jason Andryuk
2020-01-21 21:28     ` Marek Marczykowski-Górecki
2020-01-22 14:43       ` Jason Andryuk
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 09/16] libxl: add save/restore support for qemu-xen in stubdomain Marek Marczykowski-Górecki
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 10/16] tools: add missing libxenvchan cflags Marek Marczykowski-Górecki
2020-01-20 19:58   ` Jason Andryuk
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 11/16] tools: add simple vchan-socket-proxy Marek Marczykowski-Górecki
2020-01-15 11:02   ` Jan Beulich
2020-01-16 17:11     ` Marek Marczykowski-Górecki
2020-01-17  8:13       ` Jan Beulich
2020-01-17 18:44   ` Rich Persaud
2020-01-17 18:56     ` Marek Marczykowski-Górecki
2020-01-21 19:43   ` Jason Andryuk [this message]
2020-01-21 23:09     ` Marek Marczykowski-Górecki
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 12/16] libxl: use vchan for QMP access with Linux stubdomain Marek Marczykowski-Górecki
2020-01-21 20:17   ` Jason Andryuk
2020-01-21 23:46     ` Marek Marczykowski-Górecki
2020-01-24 14:05       ` Jason Andryuk
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 13/16] Regenerate autotools files Marek Marczykowski-Górecki
2020-01-15 21:57   ` Rich Persaud
2020-01-21 20:56     ` Marek Marczykowski-Górecki
2020-01-21 21:28       ` Rich Persaud
2020-01-22  8:57         ` Lars Kurth
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 14/16] libxl: require qemu in dom0 even if stubdomain is in use Marek Marczykowski-Górecki
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 15/16] libxl: ignore emulated IDE disks beyond the first 4 Marek Marczykowski-Górecki
2020-01-21 20:24   ` Jason Andryuk
2020-01-15  2:39 ` [Xen-devel] [PATCH v4 16/16] libxl: consider also qemu in stubdomain in libxl__dm_active check Marek Marczykowski-Górecki
2020-01-21 20:25   ` Jason Andryuk
2020-01-22 16:50 ` [Xen-devel] [PATCH v4 00/16] Add support for qemu-xen runnning in a Linux-based stubdomain Jason Andryuk

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