swaybg: one instance for all outputs

This makes it so there will only be one swaybg instance running
instead of one per output. swaybg's cli has been changed to a xrandr
like interface, where you select an output and then change properties
for that output and then select another output and repeat. This also
makes it so swaybg is only killed and respawned when a background
changes or when reloading.

1 files changed, 148 insertions, 104 deletions

diff --git a/sway/config/output.c b/sway/config/output.c
index d06051b3..0473d0ad 100644
--- a/sway/config/output.c
+++ b/sway/config/output.c
@@ -228,91 +228,6 @@ static bool set_mode(struct wlr_output *output, int width, int height,
         return wlr_output_set_mode(output, best);
 }
 
-static void handle_swaybg_client_destroy(struct wl_listener *listener,
-                void *data) {
-        struct sway_output *output =
-                wl_container_of(listener, output, swaybg_client_destroy);
-        wl_list_remove(&output->swaybg_client_destroy.link);
-        wl_list_init(&output->swaybg_client_destroy.link);
-        output->swaybg_client = NULL;
-}
-
-static bool set_cloexec(int fd, bool cloexec) {
-        int flags = fcntl(fd, F_GETFD);
-        if (flags == -1) {
-                sway_log_errno(SWAY_ERROR, "fcntl failed");
-                return false;
-        }
-        if (cloexec) {
-                flags = flags | FD_CLOEXEC;
-        } else {
-                flags = flags & ~FD_CLOEXEC;
-        }
-        if (fcntl(fd, F_SETFD, flags) == -1) {
-                sway_log_errno(SWAY_ERROR, "fcntl failed");
-                return false;
-        }
-        return true;
-}
-
-static bool spawn_swaybg(struct sway_output *output, char *const cmd[]) {
-        int sockets[2];
-        if (socketpair(AF_UNIX, SOCK_STREAM, 0, sockets) != 0) {
-                sway_log_errno(SWAY_ERROR, "socketpair failed");
-                return false;
-        }
-        if (!set_cloexec(sockets[0], true) || !set_cloexec(sockets[1], true)) {
-                return false;
-        }
-
-        output->swaybg_client = wl_client_create(server.wl_display, sockets[0]);
-        if (output->swaybg_client == NULL) {
-                sway_log_errno(SWAY_ERROR, "wl_client_create failed");
-                return false;
-        }
-
-        output->swaybg_client_destroy.notify = handle_swaybg_client_destroy;
-        wl_client_add_destroy_listener(output->swaybg_client,
-                &output->swaybg_client_destroy);
-
-        pid_t pid = fork();
-        if (pid < 0) {
-                sway_log_errno(SWAY_ERROR, "fork failed");
-                return false;
-        } else if (pid == 0) {
-                pid = fork();
-                if (pid < 0) {
-                        sway_log_errno(SWAY_ERROR, "fork failed");
-                        _exit(EXIT_FAILURE);
-                } else if (pid == 0) {
-                        if (!set_cloexec(sockets[1], false)) {
-                                _exit(EXIT_FAILURE);
-                        }
-
-                        char wayland_socket_str[16];
-                        snprintf(wayland_socket_str, sizeof(wayland_socket_str),
-                                "%d", sockets[1]);
-                        setenv("WAYLAND_SOCKET", wayland_socket_str, true);
-
-                        execvp(cmd[0], cmd);
-                        sway_log_errno(SWAY_ERROR, "execvp failed");
-                        _exit(EXIT_FAILURE);
-                }
-                _exit(EXIT_SUCCESS);
-        }
-
-        if (close(sockets[1]) != 0) {
-                sway_log_errno(SWAY_ERROR, "close failed");
-                return false;
-        }
-        if (waitpid(pid, NULL, 0) < 0) {
-                sway_log_errno(SWAY_ERROR, "waitpid failed");
-                return false;
-        }
-
-        return true;
-}
-
 bool apply_output_config(struct output_config *oc, struct sway_output *output) {
         if (output == root->noop_output) {
                 return false;
@@ -397,25 +312,6 @@ bool apply_output_config(struct output_config *oc, struct sway_output *output) {
         wlr_output_transformed_resolution(wlr_output,
                 &output->width, &output->height);
 
-        if (output->swaybg_client != NULL) {
-                wl_client_destroy(output->swaybg_client);
-        }
-        if (oc && oc->background && config->swaybg_command) {
-                sway_log(SWAY_DEBUG, "Setting background for output %s to %s",
-                        wlr_output->name, oc->background);
-
-                char *const cmd[] = {
-                        config->swaybg_command,
-                        wlr_output->name,
-                        oc->background,
-                        oc->background_option,
-                        oc->background_fallback ? oc->background_fallback : NULL,
-                        NULL,
-                };
-                if (!spawn_swaybg(output, cmd)) {
-                        return false;
-                }
-        }
 
         if (oc && oc->dpms_state == DPMS_OFF) {
                 sway_log(SWAY_DEBUG, "Turning off screen");
@@ -584,3 +480,151 @@ void free_output_config(struct output_config *oc) {
         free(oc->background_option);
         free(oc);
 }
+
+static void handle_swaybg_client_destroy(struct wl_listener *listener,
+                void *data) {
+        wl_list_remove(&config->swaybg_client_destroy.link);
+        wl_list_init(&config->swaybg_client_destroy.link);
+        config->swaybg_client = NULL;
+}
+
+static bool set_cloexec(int fd, bool cloexec) {
+        int flags = fcntl(fd, F_GETFD);
+        if (flags == -1) {
+                sway_log_errno(SWAY_ERROR, "fcntl failed");
+                return false;
+        }
+        if (cloexec) {
+                flags = flags | FD_CLOEXEC;
+        } else {
+                flags = flags & ~FD_CLOEXEC;
+        }
+        if (fcntl(fd, F_SETFD, flags) == -1) {
+                sway_log_errno(SWAY_ERROR, "fcntl failed");
+                return false;
+        }
+        return true;
+}
+
+static bool _spawn_swaybg(char **command) {
+        if (config->swaybg_client != NULL) {
+                wl_client_destroy(config->swaybg_client);
+        }
+        int sockets[2];
+        if (socketpair(AF_UNIX, SOCK_STREAM, 0, sockets) != 0) {
+                sway_log_errno(SWAY_ERROR, "socketpair failed");
+                return false;
+        }
+        if (!set_cloexec(sockets[0], true) || !set_cloexec(sockets[1], true)) {
+                return false;
+        }
+
+        config->swaybg_client = wl_client_create(server.wl_display, sockets[0]);
+        if (config->swaybg_client == NULL) {
+                sway_log_errno(SWAY_ERROR, "wl_client_create failed");
+                return false;
+        }
+
+        config->swaybg_client_destroy.notify = handle_swaybg_client_destroy;
+        wl_client_add_destroy_listener(config->swaybg_client,
+                &config->swaybg_client_destroy);
+
+        pid_t pid = fork();
+        if (pid < 0) {
+                sway_log_errno(SWAY_ERROR, "fork failed");
+                return false;
+        } else if (pid == 0) {
+                pid = fork();
+                if (pid < 0) {
+                        sway_log_errno(SWAY_ERROR, "fork failed");
+                        _exit(EXIT_FAILURE);
+                } else if (pid == 0) {
+                        if (!set_cloexec(sockets[1], false)) {
+                                _exit(EXIT_FAILURE);
+                        }
+
+                        char wayland_socket_str[16];
+                        snprintf(wayland_socket_str, sizeof(wayland_socket_str),
+                                "%d", sockets[1]);
+                        setenv("WAYLAND_SOCKET", wayland_socket_str, true);
+
+                        execvp(command[0], command);
+                        sway_log_errno(SWAY_ERROR, "execvp failed");
+                        _exit(EXIT_FAILURE);
+                }
+                _exit(EXIT_SUCCESS);
+        }
+
+        if (close(sockets[1]) != 0) {
+                sway_log_errno(SWAY_ERROR, "close failed");
+                return false;
+        }
+        if (waitpid(pid, NULL, 0) < 0) {
+                sway_log_errno(SWAY_ERROR, "waitpid failed");
+                return false;
+        }
+
+        return true;
+}
+
+bool spawn_swaybg(void) {
+        if (!config->swaybg_command) {
+                return true;
+        }
+
+        size_t length = 2;
+        for (int i = 0; i < config->output_configs->length; i++) {
+                struct output_config *oc = config->output_configs->items[i];
+                if (!oc->background) {
+                        continue;
+                }
+                if (strcmp(oc->background_option, "solid_color") == 0) {
+                        length += 4;
+                } else if (oc->background_fallback) {
+                        length += 8;
+                } else {
+                        length += 6;
+                }
+        }
+
+        char **cmd = calloc(1, sizeof(char **) * length);
+        if (!cmd) {
+                sway_log(SWAY_ERROR, "Failed to allocate spawn_swaybg command");
+                return false;
+        }
+
+        size_t i = 0;
+        cmd[i++] = config->swaybg_command;
+        for (int j = 0; j < config->output_configs->length; j++) {
+                struct output_config *oc = config->output_configs->items[j];
+                if (!oc->background) {
+                        continue;
+                }
+                if (strcmp(oc->background_option, "solid_color") == 0) {
+                        cmd[i++] = "-o";
+                        cmd[i++] = oc->name;
+                        cmd[i++] = "-c";
+                        cmd[i++] = oc->background;
+                } else {
+                        cmd[i++] = "-o";
+                        cmd[i++] = oc->name;
+                        cmd[i++] = "-i";
+                        cmd[i++] = oc->background;
+                        cmd[i++] = "-m";
+                        cmd[i++] = oc->background_option;
+                        if (oc->background_fallback) {
+                                cmd[i++] = "-c";
+                                cmd[i++] = oc->background_fallback;
+                        }
+                }
+                assert(i <= length);
+        }
+
+        for (size_t k = 0; k < i; k++) {
+                sway_log(SWAY_DEBUG, "spawn_swaybg cmd[%ld] = %s", k, cmd[k]);
+        }
+
+        bool result = _spawn_swaybg(cmd);
+        free(cmd);
+        return result;
+}