url-mode: add support for XDG activation when opening URLs

First, add a ‘token’ argument to spawn(). When non-NULL, spawn() will
set the ‘XDG_ACTIVATION_TOKEN’ environment variable in the forked
process. If DISPLAY is non-NULL, we also set DESKTOP_STARTUP_ID, for
compatibility with X11 applications. Note that failing to set either
of these environment variables are considered non-fatal - i.e. we
ignore failures.

Next, add a helper function, wayl_get_activation_token(), to generate
an XDG activation token, and call a user-provided callback when it’s
‘done (since token generation is asynchronous). This function takes an
optional ‘seat’ and ‘serial’ arguments - when both are non-NULL/zero,
we set the serial on the token. ‘win’ is a required argument, used to
set the surface on the token.

Re-write wayl_win_set_urgent() to use the new helper function.

Finally, rewrite activate_url() to first try to get an activation
token (and spawn the URL launcher in the token callback). If that
fails, or if we don’t have XDG activation support, spawn the URL
launcher immediately (like before this patch).

Closes #1058

CHANGELOG.md

@@ -41,6 +41,12 @@
 
 ## Unreleased
 ### Added
+
+* XDG activation support when opening URLs ([#1058][1058]).
+
+[1058]: https://codeberg.org/dnkl/foot/issues/1058
+
+
 ### Changed
 ### Deprecated
 ### Removed

input.c

@@ -281,7 +281,8 @@ execute_binding(struct seat *seat, struct terminal *term,
             }
         }
 
-        if (!spawn(term->reaper, NULL, binding->aux->pipe.args, pipe_fd[0], stdout_fd, stderr_fd))
+        if (!spawn(term->reaper, NULL, binding->aux->pipe.args,
+                   pipe_fd[0], stdout_fd, stderr_fd, NULL))
             goto pipe_err;
 
         /* Close read end */

notify.c

@@ -48,7 +48,7 @@ notify_notify(const struct terminal *term, const char *title, const char *body)
 
     /* Redirect stdin to /dev/null, but ignore failure to open */
     int devnull = open("/dev/null", O_RDONLY);
-    spawn(term->reaper, NULL, argv, devnull, -1, -1);
+    spawn(term->reaper, NULL, argv, devnull, -1, -1, NULL);
 
     if (devnull >= 0)
         close(devnull);

spawn.c

@@ -17,7 +17,8 @@
 
 bool
 spawn(struct reaper *reaper, const char *cwd, char *const argv[],
-      int stdin_fd, int stdout_fd, int stderr_fd)
+      int stdin_fd, int stdout_fd, int stderr_fd,
+      const char *xdg_activation_token)
 {
     int pipe_fds[2] = {-1, -1};
     if (pipe2(pipe_fds, O_CLOEXEC) < 0) {
@@ -47,14 +48,24 @@ spawn(struct reaper *reaper, const char *cwd, char *const argv[],
         /* Restore ignored (SIG_IGN) signals */
         struct sigaction dfl = {.sa_handler = SIG_DFL};
         sigemptyset(&dfl.sa_mask);
-        if (sigaction(SIGHUP, &dfl, NULL) < 0)
+        if (sigaction(SIGHUP, &dfl, NULL) < 0 ||
+            sigaction(SIGPIPE, &dfl, NULL) < 0)
+        {
             goto child_err;
+        }
 
         if (cwd != NULL && chdir(cwd) < 0) {
             LOG_WARN("failed to change working directory to %s: %s",
                      cwd, strerror(errno));
         }
 
+        if (xdg_activation_token != NULL) {
+            setenv("XDG_ACTIVATION_TOKEN", xdg_activation_token, 1);
+
+            if (getenv("DISPLAY") != NULL)
+                setenv("DESKTOP_STARTUP_ID", xdg_activation_token, 1);
+        }
+
         bool close_stderr = stderr_fd >= 0;
         bool close_stdout = stdout_fd >= 0 && stdout_fd != stderr_fd;
         bool close_stdin = stdin_fd >= 0 && stdin_fd != stdout_fd && stdin_fd != stderr_fd;

spawn.h

@@ -5,7 +5,8 @@
 #include "reaper.h"
 
 bool spawn(struct reaper *reaper, const char *cwd, char *const argv[],
-           int stdin_fd, int stdout_fd, int stderr_fd);
+           int stdin_fd, int stdout_fd, int stderr_fd,
+           const char *xdg_activation_token);
 
 bool spawn_expand_template(
     const struct config_spawn_template *template,

terminal.c

@@ -3119,7 +3119,8 @@ term_bell(struct terminal *term)
         (!term->kbd_focus || term->conf->bell.command_focused))
     {
         int devnull = open("/dev/null", O_RDONLY);
-        spawn(term->reaper, NULL, term->conf->bell.command.argv.args, devnull, -1, -1);
+        spawn(term->reaper, NULL, term->conf->bell.command.argv.args,
+              devnull, -1, -1, NULL);
 
         if (devnull >= 0)
             close(devnull);
@@ -3131,7 +3132,7 @@ term_spawn_new(const struct terminal *term)
 {
     return spawn(
         term->reaper, term->cwd, (char *const []){term->foot_exe, NULL},
-        -1, -1, -1);
+        -1, -1, -1, NULL);
 }
 
 void

url-mode.c

@@ -50,8 +50,86 @@ execute_binding(struct seat *seat, struct terminal *term,
     return true;
 }
 
+static bool
+spawn_url_launcher_with_token(struct terminal *term,
+                              const char *url,
+                              const char *xdg_activation_token)
+{
+    size_t argc;
+    char **argv;
+
+    int dev_null = open("/dev/null", O_RDWR);
+
+    if (dev_null < 0) {
+        LOG_ERRNO("failed to open /dev/null");
+        return false;
+    }
+
+    bool ret = false;
+
+    if (spawn_expand_template(
+            &term->conf->url.launch, 1,
+            (const char *[]){"url"},
+            (const char *[]){url},
+            &argc, &argv))
+    {
+        ret = spawn(term->reaper, term->cwd, argv,
+              dev_null, dev_null, dev_null, xdg_activation_token);
+
+        for (size_t i = 0; i < argc; i++)
+            free(argv[i]);
+        free(argv);
+    }
+
+    close(dev_null);
+    return ret;
+}
+
+#if defined(HAVE_XDG_ACTIVATION)
+struct spawn_activation_context {
+    struct terminal *term;
+    char *url;
+};
+
 static void
-activate_url(struct seat *seat, struct terminal *term, const struct url *url)
+activation_token_done(const char *token, void *data)
+{
+    struct spawn_activation_context *ctx = data;
+
+    spawn_url_launcher_with_token(ctx->term, ctx->url, token);
+    free(ctx->url);
+    free(ctx);
+}
+#endif
+
+static bool
+spawn_url_launcher(struct seat *seat, struct terminal *term, const char *url,
+                   uint32_t serial)
+{
+#if defined(HAVE_XDG_ACTIVATION)
+    struct spawn_activation_context *ctx = xmalloc(sizeof(*ctx));
+    *ctx = (struct spawn_activation_context){
+        .term = term,
+        .url = xstrdup(url),
+    };
+
+    if (wayl_get_activation_token(
+            seat->wayl, seat, serial, term->window, &activation_token_done, ctx))
+    {
+        /* Context free:d by callback */
+        return true;
+    }
+
+    free(ctx->url);
+    free(ctx);
+#endif
+
+    return spawn_url_launcher_with_token(term, url, NULL);
+}
+
+static void
+activate_url(struct seat *seat, struct terminal *term, const struct url *url,
+             uint32_t serial)
 {
     char *url_string = NULL;
 
@@ -87,30 +165,7 @@ activate_url(struct seat *seat, struct terminal *term, const struct url *url)
 
     case URL_ACTION_LAUNCH:
     case URL_ACTION_PERSISTENT: {
-        size_t argc;
+        spawn_url_launcher(seat, term, url_string, serial);
-        char **argv;
-
-        int dev_null = open("/dev/null", O_RDWR);
-
-        if (dev_null < 0) {
-            LOG_ERRNO("failed to open /dev/null");
-            break;
-        }
-
-        if (spawn_expand_template(
-                &term->conf->url.launch, 1,
-                (const char *[]){"url"},
-                (const char *[]){url_string},
-                &argc, &argv))
-        {
-            spawn(term->reaper, term->cwd, argv, dev_null, dev_null, dev_null);
-
-            for (size_t i = 0; i < argc; i++)
-                free(argv[i]);
-            free(argv);
-        }
-
-        close(dev_null);
         break;
     }
     }
@@ -207,7 +262,7 @@ urls_input(struct seat *seat, struct terminal *term,
     }
 
     if (match) {
-        activate_url(seat, term, match);
+        activate_url(seat, term, match, serial);
 
         switch (match->action) {
         case URL_ACTION_COPY:

wayland.c

@@ -1566,8 +1566,12 @@ wayl_win_destroy(struct wl_window *win)
     shm_purge(term->render.chains.csd);
 
 #if defined(HAVE_XDG_ACTIVATION)
-    if (win->xdg_activation_token != NULL)
+    tll_foreach(win->xdg_tokens, it) {
-        xdg_activation_token_v1_destroy(win->xdg_activation_token);
+        xdg_activation_token_v1_destroy(it->item->xdg_token);
+        free(it->item);
+
+        tll_remove(win->xdg_tokens, it);
+    }
 #endif
     if (win->frame_callback != NULL)
         wl_callback_destroy(win->frame_callback);
@@ -1706,51 +1710,21 @@ wayl_roundtrip(struct wayland *wayl)
 
 #if defined(HAVE_XDG_ACTIVATION)
 static void
-activation_token_done(void *data, struct xdg_activation_token_v1 *xdg_token,
+activation_token_for_urgency_done(const char *token, void *data)
-                      const char *token)
 {
     struct wl_window *win = data;
     struct wayland *wayl = win->term->wl;
 
-    LOG_DBG("activation token: %s", token);
-
     xdg_activation_v1_activate(wayl->xdg_activation, token, win->surface);
-
-    xassert(win->xdg_activation_token == xdg_token);
-    xdg_activation_token_v1_destroy(xdg_token);
-    win->xdg_activation_token = NULL;
 }
-
-static const struct xdg_activation_token_v1_listener activation_token_listener = {
-    .done = &activation_token_done,
-};
 #endif /* HAVE_XDG_ACTIVATION */
 
 bool
 wayl_win_set_urgent(struct wl_window *win)
 {
 #if defined(HAVE_XDG_ACTIVATION)
-    struct wayland *wayl = win->term->wl;
+    return wayl_get_activation_token(
-
+        win->term->wl, NULL, 0, win, &activation_token_for_urgency_done, win);
-    if (wayl->xdg_activation == NULL)
-        return false;
-
-    if (win->xdg_activation_token != NULL)
-        return true;
-
-    struct xdg_activation_token_v1 *token =
-        xdg_activation_v1_get_activation_token(wayl->xdg_activation);
-
-    if (token == NULL) {
-        LOG_ERR("failed to retrieve XDG activation token");
-        return false;
-    }
-
-    xdg_activation_token_v1_add_listener(token, &activation_token_listener, win);
-    xdg_activation_token_v1_set_surface(token, win->surface);
-    xdg_activation_token_v1_commit(token);
-    win->xdg_activation_token = token;
-    return true;
 #else
     return false;
 #endif
@@ -1833,3 +1807,72 @@ wayl_win_subsurface_destroy(struct wl_surf_subsurf *surf)
     surf->surf = NULL;
     surf->sub = NULL;
 }
+
+#if defined(HAVE_XDG_ACTIVATION)
+
+static void
+activation_token_done(void *data, struct xdg_activation_token_v1 *xdg_token,
+                      const char *token)
+{
+    LOG_DBG("XDG activation token done: %s", token);
+
+    struct xdg_activation_token_context *ctx = data;
+    struct wl_window *win = ctx->win;
+
+    ctx->cb(token, ctx->cb_data);
+
+    tll_foreach(win->xdg_tokens, it) {
+        if (it->item->xdg_token != xdg_token)
+            continue;
+
+        xassert(win == it->item->win);
+
+        free(ctx);
+        xdg_activation_token_v1_destroy(xdg_token);
+        tll_remove(win->xdg_tokens, it);
+        return;
+    }
+
+    xassert(false);
+}
+
+static const struct
+xdg_activation_token_v1_listener activation_token_listener = {
+    .done = &activation_token_done,
+};
+
+bool
+wayl_get_activation_token(
+    struct wayland *wayl, struct seat *seat, uint32_t serial,
+    struct wl_window *win,
+    void (*cb)(const char *token, void *data), void *cb_data)
+{
+    if (wayl->xdg_activation == NULL)
+        return false;
+
+    struct xdg_activation_token_v1 *token =
+        xdg_activation_v1_get_activation_token(wayl->xdg_activation);
+
+    if (token == NULL) {
+        LOG_ERR("failed to retrieve XDG activation token");
+        return false;
+    }
+
+    struct xdg_activation_token_context *ctx = xmalloc(sizeof(*ctx));
+    *ctx = (struct xdg_activation_token_context){
+        .win = win,
+        .xdg_token = token,
+        .cb = cb,
+        .cb_data = cb_data,
+    };
+    tll_push_back(win->xdg_tokens, ctx);
+
+    if (seat != NULL && serial != 0)
+        xdg_activation_token_v1_set_serial(token, serial, seat->wl_seat);
+
+    xdg_activation_token_v1_set_surface(token, win->surface);
+    xdg_activation_token_v1_add_listener(token, &activation_token_listener, ctx);
+    xdg_activation_token_v1_commit(token);
+    return true;
+}
+#endif

wayland.h

@@ -295,6 +295,22 @@ struct wl_url {
 
 enum csd_mode {CSD_UNKNOWN, CSD_NO, CSD_YES};
 
+#if defined(HAVE_XDG_ACTIVATION)
+typedef void (*activation_token_cb_t)(const char *token, void *data);
+
+/*
+ * This context holds data used both in the token::done callback, and
+ * when cleaning up created, by not-yet-done tokens in
+ * wayl_win_destroy().
+ */
+struct xdg_activation_token_context {
+    struct wl_window *win;                        /* Need for win->xdg_tokens */
+    struct xdg_activation_token_v1 *xdg_token;    /* Used to match token in done() */
+    activation_token_cb_t cb;                     /* User provided callback */
+    void *cb_data;                                /* Callback user pointer */
+};
+#endif
+
 struct wayland;
 struct wl_window {
     struct terminal *term;
@@ -302,7 +318,7 @@ struct wl_window {
     struct xdg_surface *xdg_surface;
     struct xdg_toplevel *xdg_toplevel;
 #if defined(HAVE_XDG_ACTIVATION)
-    struct xdg_activation_token_v1 *xdg_activation_token;
+    tll(struct xdg_activation_token_context *) xdg_tokens;
 #endif
 
     struct zxdg_toplevel_decoration_v1 *xdg_toplevel_decoration;
@@ -417,3 +433,9 @@ bool wayl_win_subsurface_new_with_custom_parent(
     struct wl_window *win, struct wl_surface *parent,
     struct wl_surf_subsurf *surf, bool allow_pointer_input);
 void wayl_win_subsurface_destroy(struct wl_surf_subsurf *surf);
+
+#if defined(HAVE_XDG_ACTIVATION)
+bool wayl_get_activation_token(
+    struct wayland *wayl, struct seat *seat, uint32_t serial,
+    struct wl_window *win, activation_token_cb_t cb, void *cb_data);
+#endif