[virt-tools-list] [PATCH v2 1/3] remote-viewer: learn '-' as URI for standard input connection file

Victor Toso victortoso at redhat.com
Tue Nov 14 16:46:10 UTC 2017


Hi,

On Tue, Nov 14, 2017 at 11:39:54AM -0500, Marc-André Lureau wrote:
> Hi
> 
> ----- Original Message -----
> > Hi,
> > 
> > On Tue, Nov 14, 2017 at 04:56:01PM +0100, marcandre.lureau at redhat.com wrote:
> > > From: Marc-André Lureau <marcandre.lureau at redhat.com>
> > > 
> > > Some users want the ability to set connection details without writing
> > > to a file or passing command line arguments.
> > > 
> > > Learn to read the connection file from standard input for such use
> > > case.
> > > 
> > > This allows a parent process to set the connection details without
> > > intermediary file.
> > > 
> > > Signed-off-by: Marc-André Lureau <marcandre.lureau at redhat.com>
> > > Reviewed-by: Victor Toso <victortoso at redhat.com>
> > > ---
> > >  man/remote-viewer.pod  |  3 +++
> > >  src/remote-viewer.c    | 46 ++++++++++++++++++++++++++++++++++++++++------
> > >  src/virt-viewer-file.c | 31 +++++++++++++++++++++++++------
> > >  src/virt-viewer-file.h |  2 ++
> > >  4 files changed, 70 insertions(+), 12 deletions(-)
> > > 
> > > diff --git a/man/remote-viewer.pod b/man/remote-viewer.pod
> > > index 60ea3a6..8428c80 100644
> > > --- a/man/remote-viewer.pod
> > > +++ b/man/remote-viewer.pod
> > > @@ -18,6 +18,9 @@ entry and a list of previously successfully accessed URI.
> > >  The URI can also point to a connection settings file, see the CONNECTION
> > >  FILE
> > >  section for a description of the format.
> > >  
> > > +If URI is '-', then remote-viewer will read the standard input as a
> > > +connection settings file and attempt to connect using it.
> > > +
> > >  =head1 OPTIONS
> > >  
> > >  The following options are accepted when running C<remote-viewer>:
> > > diff --git a/src/remote-viewer.c b/src/remote-viewer.c
> > > index fb5376c..e082178 100644
> > > --- a/src/remote-viewer.c
> > > +++ b/src/remote-viewer.c
> > > @@ -1084,6 +1084,22 @@ remote_viewer_session_connected(VirtViewerSession
> > > *session,
> > >      g_free(uri);
> > >  }
> > >  
> > > +static gchar *
> > > +read_all_stdin(gsize *len, GError **err)
> > > +{
> > > +    GIOChannel *ioc = g_io_channel_unix_new(fileno(stdin));
> > > +    gchar *content = NULL;
> > > +    GIOStatus status;
> > > +
> > > +    status = g_io_channel_read_to_end(ioc, &content, len, err);
> > > +    g_assert(status != G_IO_STATUS_AGAIN && status != G_IO_STATUS_EOF);
> > 
> > "G_IO_STATUS_NORMAL on success. This function never returns G_IO_STATUS_EOF"
> 
> Yes, I also want to assert we don't get AGAIN (or should we loop?) I
> don't think it's necessary, stdin should be blocking and this would be
> a weird case, wouldn't it?

It would. I just don't see the point on checking with G_IO_STATUS_EOF if
documentation says it should never return it. IMHO, checking
G_IO_STATUS_AGAIN should be fine.

> > > +
> > > +    g_io_channel_unref(ioc);
> > > +    g_assert((content && !*err) || (!content && *err));
> > 
> > This seems that you are sanity checking g_io_channel_read_to_end() ?
> 
> I want to make sure that either we get an error or we get content, not
> both. It's not clear for the API (for ex with AGAIN).

I agree

> > 
> > If you want to assert here, I guess just use g_assert_no_error()
> > instead ?
> 
> That was basically the approach before, let the function return NULL,
> and fail later when reading from NULL buffer with keyfile.
> 
> Now if we want to produce a error message instead, we should propagate
> GError.
> 
> Other solution is to pring the GError immediately if any, and return
> NULL in that case. Anything works for me.

Feel free to keep it as is.

> > > +
> > > +    return content;
> > > +}
> > > +
> > >  static gboolean
> > >  remote_viewer_initial_connect(RemoteViewer *self, const gchar *type,
> > >                                VirtViewerFile *vvfile, GError **error)
> > > @@ -1174,16 +1190,34 @@ retry_dialog:
> > >  
> > >          g_debug("Opening display to %s", guri);
> > >  
> > > -        file = g_file_new_for_commandline_arg(guri);
> > > -        if (g_file_query_exists(file, NULL)) {
> > > -            gchar *path = g_file_get_path(file);
> > > -            vvfile = virt_viewer_file_new(path, &error);
> > > -            g_free(path);
> > > +        if (!g_strcmp0(guri, "-")) {
> > > +            gsize len = 0;
> > > +            gchar *buf = read_all_stdin(&len, &error);
> > > +
> > >              if (error) {
> > > -                g_prefix_error(&error, _("Invalid file %s: "), guri);
> > > +                g_prefix_error(&error, _("Failed to read stdin: "));
> > >                  g_warning("%s", error->message);
> > >                  goto cleanup;
> > >              }
> > > +
> > > +            vvfile = virt_viewer_file_new_from_buffer(buf, len, &error);
> > > +            g_free(buf);
> > > +        } else {
> > > +            file = g_file_new_for_commandline_arg(guri);
> > > +            if (g_file_query_exists(file, NULL)) {
> > > +                gchar *path = g_file_get_path(file);
> > > +                vvfile = virt_viewer_file_new(path, &error);
> > > +                g_free(path);
> > > +            }
> > > +        }
> > > +
> > > +        if (error) {
> > > +            g_prefix_error(&error, _("Invalid file %s: "), guri);
> > > +            g_warning("%s", error->message);
> > > +            goto cleanup;
> > > +        }
> > > +
> > > +        if (vvfile) {
> > >              g_object_get(G_OBJECT(vvfile), "type", &type, NULL);
> > >          } else if (virt_viewer_util_extract_host(guri, &type, NULL, NULL,
> > >          NULL, NULL) < 0 || type == NULL) {
> > >              g_set_error_literal(&error,
> > > diff --git a/src/virt-viewer-file.c b/src/virt-viewer-file.c
> > > index 9ff2a05..1b0c310 100644
> > > --- a/src/virt-viewer-file.c
> > > +++ b/src/virt-viewer-file.c
> > > @@ -139,16 +139,15 @@ enum  {
> > >  };
> > >  
> > >  VirtViewerFile*
> > > -virt_viewer_file_new(const gchar* location, GError** error)
> > > +virt_viewer_file_new_from_buffer(const gchar* data, gsize len,
> > > +                                 GError** error)
> > >  {
> > >      GError* inner_error = NULL;
> > > -
> > > -    g_return_val_if_fail (location != NULL, NULL);
> > > -
> > >      VirtViewerFile* self =
> > >      VIRT_VIEWER_FILE(g_object_new(VIRT_VIEWER_TYPE_FILE, NULL));
> > >      GKeyFile* keyfile = self->priv->keyfile;
> > >  
> > > -    g_key_file_load_from_file(keyfile, location,
> > > +    g_return_val_if_fail(data != NULL, NULL);
> > > +    g_key_file_load_from_data(keyfile, data, len,
> > >                                G_KEY_FILE_KEEP_COMMENTS |
> > >                                G_KEY_FILE_KEEP_TRANSLATIONS,
> > >                                &inner_error);
> > >      if (inner_error != NULL) {
> > > @@ -166,7 +165,27 @@ virt_viewer_file_new(const gchar* location, GError**
> > > error)
> > >          return NULL;
> > >      }
> > >  
> > > -    if (virt_viewer_file_get_delete_this_file(self) &&
> > > +    return self;
> > > +}
> > > +
> > > +VirtViewerFile*
> > > +virt_viewer_file_new(const gchar* location, GError** error)
> > > +{
> > > +    VirtViewerFile *self;
> > > +    gchar *buf;
> > > +    gsize len;
> > > +
> > > +    g_return_val_if_fail (location != NULL, NULL);
> > > +
> > > +    if (!g_file_get_contents(location, &buf, &len, error)) {
> > > +        return NULL;
> > > +    }
> > > +
> > > +    self = virt_viewer_file_new_from_buffer(buf, len, error);
> > > +    g_free(buf);
> > > +
> > > +
> > > +    if (self && virt_viewer_file_get_delete_this_file(self) &&
> > >          !g_getenv("VIRT_VIEWER_KEEP_FILE")) {
> > >          if (g_unlink(location) != 0)
> > >              g_warning("failed to remove %s", location);
> > > diff --git a/src/virt-viewer-file.h b/src/virt-viewer-file.h
> > > index 6b783f9..15c61d0 100644
> > > --- a/src/virt-viewer-file.h
> > > +++ b/src/virt-viewer-file.h
> > > @@ -50,6 +50,8 @@ struct _VirtViewerFileClass
> > >  GType virt_viewer_file_get_type(void);
> > >  
> > >  VirtViewerFile* virt_viewer_file_new(const gchar* path, GError** error);
> > > +VirtViewerFile* virt_viewer_file_new_from_buffer(const gchar* buf, gsize
> > > len,
> > > +                                                 GError** error);
> > >  gboolean virt_viewer_file_is_set(VirtViewerFile* self, const gchar* key);
> > >  
> > >  gchar* virt_viewer_file_get_ca(VirtViewerFile* self);
> > > --
> > > 2.15.0.125.g8f49766d64
> > > 
> > 
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