On Fri, 18 Jul 2014 11:05:03 +0200
Marek Chalupa <mchqwe...@gmail.com> wrote:
> On 17 July 2014 19:54, Jasper St. Pierre <jstpie...@mecheye.net> wrote:
>
> > This allows compositors to easily select a good display to listen on.
> > ---
> > src/wayland-server.c | 97
> > ++++++++++++++++++++++++++++++++++++++--------------
> > src/wayland-server.h | 1 +
> > 2 files changed, 73 insertions(+), 25 deletions(-)
Hi,
the final series that actually got pushed was never on the mailing
list, so sorry for the crappy quote.
I have one observation.
server: Add a simple API to find a good default display
This allows compositors to easily select a good display to listen on.
----------------------------- src/wayland-server.c -----------------------------
index b3929ed..39d29ec 100644
@@ -1093,19 +1093,90 @@ wl_socket_init_for_display_name(struct wl_socket *s,
const char *name)
errno = ENAMETOOLONG;
return -1;
};
return 0;
}
+static int
+_wl_display_add_socket(struct wl_display *display, struct wl_socket *s)
+{
+ socklen_t size;
+
+ s->fd = wl_os_socket_cloexec(PF_LOCAL, SOCK_STREAM, 0);
+ if (s->fd < 0) {
+ return -1;
+ }
+
+ size = offsetof (struct sockaddr_un, sun_path) +
strlen(s->addr.sun_path);
+ if (bind(s->fd, (struct sockaddr *) &s->addr, size) < 0) {
+ wl_log("bind() failed with error: %m\n");
+ return -1;
+ }
+
+ if (listen(s->fd, 1) < 0) {
+ wl_log("listen() failed with error: %m\n");
+ return -1;
+ }
+
+ s->source = wl_event_loop_add_fd(display->loop, s->fd,
+ WL_EVENT_READABLE,
+ socket_data, display);
+ if (s->source == NULL) {
+ return -1;
+ }
+
+ wl_list_insert(display->socket_list.prev, &s->link);
+ return 0;
+}
+
+WL_EXPORT const char *
+wl_display_add_socket_auto(struct wl_display *display)
+{
+ struct wl_socket *s;
+ int displayno = 0;
+ char display_name[16] = "";
+
+ /* A reasonable number of maximum default sockets. If
+ * you need more than this, use the explicit add_socket API. */
+ const int MAX_DISPLAYNO = 32;
+
+ s = malloc(sizeof *s);
+ memset(s, 0, sizeof *s);
+ if (s == NULL)
+ return NULL;
+
+ do {
+ snprintf(display_name, sizeof display_name, "wayland-%d",
displayno);
+ if (wl_socket_init_for_display_name(s, display_name) < 0) {
+ wl_socket_destroy(s);
+ return NULL;
+ }
+
+ if (wl_socket_lock(s) < 0)
+ continue;
+
+ if (_wl_display_add_socket(display, s) < 0) {
+ wl_socket_destroy(s);
+ return NULL;
+ }
Let's imagine:
First iteration: socket already used => wl_socket_lock() fails.
Second iteration: wl_socket_init_for_display_name() happens to fail.
=> wl_socket_destroy() unlinks the existing socket's lock file.
The trick here is that reading what wl_socket_init_for_display_name()
does, it probably cannot fail on the second iteration. Would be nice to
have at least a comment here to that effect, otherwise some change in
the future may break that, as to me it seems fragile.
Or better, wl_socket_lock() should reset the lock file name before
returning an error.
+
+ return s->display_name;
+ } while (displayno++ < MAX_DISPLAYNO);
+
+ /* Ran out of display names. */
+ wl_socket_destroy(s);
+ errno = EINVAL;
+ return NULL;
+}
+
WL_EXPORT int
wl_display_add_socket(struct wl_display *display, const char *name)
{
struct wl_socket *s;
- socklen_t size;
s = malloc(sizeof *s);
memset(s, 0, sizeof *s);
if (s == NULL)
return -1;
if (name == NULL)
@@ -1119,42 +1190,19 @@ wl_display_add_socket(struct wl_display *display, const
char *name)
}
if (wl_socket_lock(s) < 0) {
wl_socket_destroy(s);
Hmm, I think there is a similar problem here. If lock fails, the
existing lock file will be unlinked from under the existing compositor.
Thanks,
pq
return -1;
}
- s->fd = wl_os_socket_cloexec(PF_LOCAL, SOCK_STREAM, 0);
- if (s->fd < 0) {
+ if (_wl_display_add_socket(display, s) < 0) {
wl_socket_destroy(s);
return -1;
}
- size = offsetof (struct sockaddr_un, sun_path) +
strlen(s->addr.sun_path);
- if (bind(s->fd, (struct sockaddr *) &s->addr, size) < 0) {
- wl_log("bind() failed with error: %m\n");
- wl_socket_destroy(s);
- return -1;
- }
-
- if (listen(s->fd, 1) < 0) {
- wl_log("listen() failed with error: %m\n");
- wl_socket_destroy(s);
- return -1;
- }
-
- s->source = wl_event_loop_add_fd(display->loop, s->fd,
- WL_EVENT_READABLE,
- socket_data, display);
- if (s->source == NULL) {
- wl_socket_destroy(s);
- return -1;
- }
- wl_list_insert(display->socket_list.prev, &s->link);
-
return 0;
}
WL_EXPORT void
wl_display_add_destroy_listener(struct wl_display *display,
struct wl_listener *listener)
{
----------------------------- src/wayland-server.h -----------------------------
index 0a3f2f6..38855c9 100644
@@ -88,14 +88,15 @@ struct wl_listener *wl_event_loop_get_destroy_listener(
struct wl_event_loop *loop,
wl_notify_func_t notify);
struct wl_display *wl_display_create(void);
void wl_display_destroy(struct wl_display *display);
struct wl_event_loop *wl_display_get_event_loop(struct wl_display *display);
int wl_display_add_socket(struct wl_display *display, const char *name);
+const char *wl_display_add_socket_auto(struct wl_display *display);
void wl_display_terminate(struct wl_display *display);
void wl_display_run(struct wl_display *display);
void wl_display_flush_clients(struct wl_display *display);
typedef void (*wl_global_bind_func_t)(struct wl_client *client, void *data,
uint32_t version, uint32_t id);
_______________________________________________
wayland-devel mailing list
wayland-devel@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/wayland-devel
