<div dir="ltr"><div><div>Oh, you're right, I didn't realize that's what that code was doing. </div> </div>Thanks! </div><div class="gmail_extra"> <div class="gmail_quote">On Fri, Aug 14, 2015 at 12:20 AM, Pekka Paalanen <<a href="mailto:ppaalanen@gmail.com" target="_blank">ppaalanen@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Wed, 12 Aug 2015 19:34:31 -0700 Dima Ryazanov <<a href="mailto:dima@gmail.com">dima@gmail.com</a>> wrote: <div><div class="h5">> Although defaulting to wayland-0 seems convenient, it has an undesirable > side effect: clients may unintentionally connect to the wrong compositor. > Generally, it's safer to fail instead. Here's a real example: > > In Fedora 22, Gtk+ prefers Wayland over X11, though the default session is still > a normal X11 Gnome session. When you launch a Gtk+ app, it will try Wayland, > fail, then try X11, and succesfully start up. That works fine. > > Now suppose you launch Weston while running the Gnome session. Suddenly, all > of the Gtk+ apps launched from Gnome will show up inside Weston instead. > That's unexpected. There's also no good way to prevent that from happening > (other than perhaps setting WAYLAND_DISPLAY to an invalid value when launching > an app). > > Not using wayland-0 as the default will solve that problem: an app launched > from the X11 Gnome session will use the X11 backend regardless of whether > there's a wayland compositor running at the same time. > > Everything else should work as before. The compositor already sets > the WAYLAND_DISPLAY when starting the session, so the lack of the default value > should not make a difference to the user. > > Signed-off-by: Dima Ryazanov <<a href="mailto:dima@gmail.com">dima@gmail.com</a>> > Acked-by: Pekka Paalanen <<a href="mailto:ppaalanen@gmail.com">ppaalanen@gmail.com</a>> > Acked-by: Giulio Camuffo <<a href="mailto:giuliocamuffo@gmail.com">giuliocamuffo@gmail.com</a>> > Acked-by: Daniel Stone <<a href="mailto:daniel@fooishbar.org">daniel@fooishbar.org</a>> > Acked-by: Jasper St. Pierre <<a href="mailto:jstpierre@mecheye.net">jstpierre@mecheye.net</a>> > --- > doc/man/wl_display_connect.xml | 5 ++--- > doc/publican/sources/Protocol.xml | 8 ++++---- > src/wayland-client.c | 10 ++++++---- > src/wayland-server.c | 6 +++--- > 4 files changed, 15 insertions(+), 14 deletions(-) > > diff --git a/doc/man/wl_display_connect.xml b/doc/man/wl_display_connect.xml > index 7e6e05c..ded3cbd 100644 > --- a/doc/man/wl_display_connect.xml > +++ b/doc/man/wl_display_connect.xml > @@ -57,9 +57,8 @@ > that was previously opened by a Wayland server. The server socket must > be placed in <envar>XDG_RUNTIME_DIR</envar> for this function to > find it. The <varname>name</varname> argument specifies the name of > - the socket or <constant>NULL</constant> to use the default (which is > - <constant>"wayland-0"</constant>). The environment variable > - <envar>WAYLAND_DISPLAY</envar> replaces the default value. If > + the socket or <constant>NULL</constant> to use the default > + (which is the value of <envar>WAYLAND_DISPLAY</envar>). If > <envar>WAYLAND_SOCKET</envar> is set, this function behaves like > <function>wl_display_connect_to_fd</function> with the file-descriptor > number taken from the environment variable.</para> > diff --git a/doc/publican/sources/Protocol.xml b/doc/publican/sources/Protocol.xml > index 477063b..9464953 100644 > --- a/doc/publican/sources/Protocol.xml > +++ b/doc/publican/sources/Protocol.xml > @@ -60,10 +60,10 @@ > <title>Wire Format</title> > <para> > The protocol is sent over a UNIX domain stream socket, where the endpoint > - usually is named <systemitem class="service">wayland-0</systemitem> > - (although it can be changed via <emphasis>WAYLAND_DISPLAY</emphasis> > - in the environment). The protocol is message-based. A > - message sent by a client to the server is called request. A message > + name is determined by the <emphasis>WAYLAND_DISPLAY</emphasis> > + environment variable. Its value will usually be > + <systemitem class="service">wayland-0</systemitem>. The protocol is message-based. > + A message sent by a client to the server is called request. A message > from the server to a client is called event. Every message is > structured as 32-bit words, values are represented in the host's > byte-order. > diff --git a/src/wayland-client.c b/src/wayland-client.c > index 09c594a..ffbca4b 100644 > --- a/src/wayland-client.c > +++ b/src/wayland-client.c > @@ -764,8 +764,11 @@ connect_to_socket(const char *name) > > if (name == NULL) > name = getenv("WAYLAND_DISPLAY"); > - if (name == NULL) > - name = "wayland-0"; > + if (name == NULL) { > + wl_log("error: WAYLAND_DISPLAY not set in the environment.\n"); > + errno = ENOENT; > + return -1; > + } > > fd = wl_os_socket_cloexec(PF_LOCAL, SOCK_STREAM, 0); > if (fd < 0) > @@ -869,8 +872,7 @@ wl_display_connect_to_fd(int fd) > * \return A \ref wl_display object or \c NULL on failure > * > * Connect to the Wayland display named \c name. If \c name is \c NULL, > - * its value will be replaced with the WAYLAND_DISPLAY environment > - * variable if it is set, otherwise display "wayland-0" will be used. > + * its value will be replaced with the WAYLAND_DISPLAY environment variable. > * > * \memberof wl_display > */ </div></div>Hi, this patch is Reviewed-by me up to this point, but I don't agree with the below change to wayland-server.c as part of this patch. > diff --git a/src/wayland-server.c b/src/wayland-server.c > index 0f04f66..1ea53f9 100644 > --- a/src/wayland-server.c > +++ b/src/wayland-server.c > @@ -1209,8 +1209,8 @@ wl_display_add_socket_auto(struct wl_display *display) > * connect to Wayland display. > * > * If NULL is passed as name, then it would look for WAYLAND_DISPLAY env > - * variable for the socket name. If WAYLAND_DISPLAY is not set, then default > - * wayland-0 is used. > + * variable for the socket name. If WAYLAND_DISPLAY is not set, this function > + * fails and returns -1. > * > * The Unix socket will be created in the directory pointed to by environment > * variable XDG_RUNTIME_DIR. If XDG_RUNTIME_DIR is not set, then this function > @@ -1235,7 +1235,7 @@ wl_display_add_socket(struct wl_display *display, const char *name) > if (name == NULL) > name = getenv("WAYLAND_DISPLAY"); > if (name == NULL) > - name = "wayland-0"; > + return -1; > > if (wl_socket_init_for_display_name(s, name) < 0) { > wl_socket_destroy(s); wl_display_add_socket() is used by the server to create a socket. If the program does not give a name parameter, it's probably ok to try and default to "wayland-0". I am not sure why WAYLAND_DISPLAY is involved at all. Anyway, the essence of this patch is to fix libwayland-client, so this change to libwayland-server is off-topic anyway and should be considered separately. I dropped the hunk to wayland-server.c and committed the rest. Pushed: 441f9bb..fb7e130 master -> master Thanks, pq </blockquote></div> </div>