Re: [PATCH v4 08/11] qmp: add 'get-win32-socket'

[Markus Armbruster <armbru@redhat.com>]

marcandre.lureau@redhat.com writes:

> From: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> A process with enough capabilities can duplicate a socket to QEMU. Add a
> QMP command to import it and add it to the monitor fd list, so it can be
> later used by other commands.
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  qapi/misc.json | 30 ++++++++++++++++++++
>  monitor/fds.c  | 76 +++++++++++++++++++++++++++++++++++++++-----------
>  2 files changed, 90 insertions(+), 16 deletions(-)
>
> diff --git a/qapi/misc.json b/qapi/misc.json
> index f0217cfba0..031c94050c 100644
> --- a/qapi/misc.json
> +++ b/qapi/misc.json
> @@ -275,6 +275,36 @@
>  ##
>  { 'command': 'getfd', 'data': {'fdname': 'str'} }
>  
> +##
> +# @get-win32-socket:
> +#
> +# Add a socket that was duplicated to QEMU process with WSADuplicateSocketW()
> +# via WSASocket() & WSAPROTOCOL_INFOW structure and assign it a name (the SOCKET
> +# is associated with a CRT file descriptor)

Long line.

> +#
> +# @info: the WSAPROTOCOL_INFOW structure (encoded in base64)
> +#
> +# @fdname: file descriptor name
> +#
> +# Returns: Nothing on success
> +#
> +# Since: 8.0
> +#
> +# Notes: If @fdname already exists, the file descriptor assigned to
> +#        it will be closed and replaced by the received file
> +#        descriptor.
> +#
> +#        The 'closefd' command can be used to explicitly close the
> +#        file descriptor when it is no longer needed.
> +#
> +# Example:
> +#
> +# -> { "execute": "get-win32-socket", "arguments": { "info": "abcd123..", fdname": "skclient" } }
> +# <- { "return": {} }
> +#
> +##
> +{ 'command': 'get-win32-socket', 'data': {'info': 'str', 'fdname': 'str'}, 'if': 'CONFIG_WIN32' }
> +
>  ##
>  # @closefd:
>  #
> diff --git a/monitor/fds.c b/monitor/fds.c
> index 7daf1064e1..9ed4197358 100644
> --- a/monitor/fds.c
> +++ b/monitor/fds.c
> @@ -61,46 +61,55 @@ struct MonFdset {
>  static QemuMutex mon_fdsets_lock;
>  static QLIST_HEAD(, MonFdset) mon_fdsets;
>  
> -void qmp_getfd(const char *fdname, Error **errp)
> +static bool monitor_add_fd(Monitor *mon, int fd, const char *fdname, Error **errp)
>  {
> -    Monitor *cur_mon = monitor_cur();
>      mon_fd_t *monfd;
> -    int fd, tmp_fd;
> -
> -    fd = qemu_chr_fe_get_msgfd(&cur_mon->chr);
> -    if (fd == -1) {
> -        error_setg(errp, "No file descriptor supplied via SCM_RIGHTS");
> -        return;
> -    }
>  
>      if (qemu_isdigit(fdname[0])) {
>          close(fd);
>          error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "fdname",
>                     "a name not starting with a digit");
> -        return;
> +        return false;
>      }
>  
>      /* See close() call below. */
> -    qemu_mutex_lock(&cur_mon->mon_lock);
> -    QLIST_FOREACH(monfd, &cur_mon->fds, next) {
> +    qemu_mutex_lock(&mon->mon_lock);
> +    QLIST_FOREACH(monfd, &mon->fds, next) {
> +        int tmp_fd;
> +
>          if (strcmp(monfd->name, fdname) != 0) {
>              continue;
>          }
>  
>          tmp_fd = monfd->fd;
>          monfd->fd = fd;
> -        qemu_mutex_unlock(&cur_mon->mon_lock);
> +        qemu_mutex_unlock(&mon->mon_lock);
>          /* Make sure close() is outside critical section */
>          close(tmp_fd);
> -        return;
> +        return true;
>      }

Have you considered factoring out the loop searching ->fds?

>  
>      monfd = g_new0(mon_fd_t, 1);
>      monfd->name = g_strdup(fdname);
>      monfd->fd = fd;
>  
> -    QLIST_INSERT_HEAD(&cur_mon->fds, monfd, next);
> -    qemu_mutex_unlock(&cur_mon->mon_lock);
> +    QLIST_INSERT_HEAD(&mon->fds, monfd, next);
> +    qemu_mutex_unlock(&mon->mon_lock);
> +    return true;
> +}
> +
> +void qmp_getfd(const char *fdname, Error **errp)
> +{
> +    Monitor *cur_mon = monitor_cur();
> +    int fd;
> +
> +    fd = qemu_chr_fe_get_msgfd(&cur_mon->chr);
> +    if (fd == -1) {
> +        error_setg(errp, "No file descriptor supplied via SCM_RIGHTS");
> +        return;
> +    }
> +
> +    monitor_add_fd(cur_mon, fd, fdname, errp);
>  }
>  
>  void qmp_closefd(const char *fdname, Error **errp)
> @@ -214,6 +223,41 @@ error:
>      return NULL;
>  }

With the doc comment tidied up:
Acked-by: Markus Armbruster <armbru@redhat.com>

The remainder is greek to me :)

>  
> +#ifdef WIN32
> +void qmp_get_win32_socket(const char *infos, const char *fdname, Error **errp)
> +{
> +    g_autofree WSAPROTOCOL_INFOW *info = NULL;
> +    gsize len;
> +    SOCKET sk;
> +    int fd;
> +
> +    info = (void *)g_base64_decode(infos, &len);
> +    if (len != sizeof(*info)) {
> +        error_setg(errp, "Invalid WSAPROTOCOL_INFOW value");
> +        return;
> +    }
> +
> +    sk = WSASocketW(FROM_PROTOCOL_INFO,
> +                    FROM_PROTOCOL_INFO,
> +                    FROM_PROTOCOL_INFO,
> +                    info, 0, 0);
> +    if (sk == INVALID_SOCKET) {
> +        error_setg_win32(errp, WSAGetLastError(), "Couldn't import socket");
> +        return;
> +    }
> +
> +    fd = _open_osfhandle(sk, _O_BINARY);
> +    if (fd < 0) {
> +        error_setg_errno(errp, errno, "Failed to associate a FD with the SOCKET");
> +        closesocket(sk);
> +        return;
> +    }
> +
> +    monitor_add_fd(monitor_cur(), fd, fdname, errp);
> +}
> +#endif
> +
> +
>  void qmp_remove_fd(int64_t fdset_id, bool has_fd, int64_t fd, Error **errp)
>  {
>      MonFdset *mon_fdset;