Reload swaybar/swaybg on config reload.

This works by tracking the pids of the child processes in the related
output container and terminating the processes and spawning new ones on
a config reload.

Should solve: #347

5 files changed, 125 insertions, 44 deletions

diff --git a/include/config.h b/include/config.h
index 32562908..1f25a0cd 100644
--- a/include/config.h
+++ b/include/config.h
@@ -184,6 +184,8 @@ int sway_mouse_binding_cmp(const void *a, const void *b);
 int sway_mouse_binding_cmp_buttons(const void *a, const void *b);
 void free_sway_mouse_binding(struct sway_mouse_binding *smb);
 
+void load_swaybars(swayc_t *output, int output_idx);
+
 /**
  * Allocate and initialize default bar configuration.
  */
diff --git a/include/container.h b/include/container.h
index 9a67a689..d76160de 100644
--- a/include/container.h
+++ b/include/container.h
@@ -1,5 +1,6 @@
 #ifndef _SWAY_CONTAINER_H
 #define _SWAY_CONTAINER_H
+#include <sys/types.h>
 #include <wlc/wlc.h>
 typedef struct sway_container swayc_t;
 
@@ -81,6 +82,11 @@ struct sway_container {
         char *class;
         char *app_id;
 
+        // Used by output containers to keep track of swaybar/swaybg child
+        // processes.
+        list_t *bar_pids;
+        pid_t bg_pid;
+
         int gaps;
 
         list_t *children;
diff --git a/sway/commands.c b/sway/commands.c
index 24d56052..13bc7dc2 100644
--- a/sway/commands.c
+++ b/sway/commands.c
@@ -1094,6 +1094,15 @@ static struct cmd_results *cmd_reload(int argc, char **argv) {
         }
         if (!load_config(NULL)) return cmd_results_new(CMD_FAILURE, "reload", "Error(s) reloading config.");
 
+        int i;
+        swayc_t *cont = NULL;
+        for (i = 0; i < root_container.children->length; ++i) {
+                cont = root_container.children->items[i];
+                if (cont->type == C_OUTPUT) {
+                        load_swaybars(cont, i);
+                }
+        }
+
         arrange_windows(&root_container, -1, -1);
         return cmd_results_new(CMD_SUCCESS, NULL, NULL);
 }
diff --git a/sway/config.c b/sway/config.c
index 970225f4..23fe5388 100644
--- a/sway/config.c
+++ b/sway/config.c
@@ -3,6 +3,9 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <wordexp.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
 #include "wayland-desktop-shell-server-protocol.h"
 #include "readline.h"
 #include "stringop.h"
@@ -360,6 +363,91 @@ void merge_output_config(struct output_config *dst, struct output_config *src) {
         }
 }
 
+static void invoke_swaybar(swayc_t *output, struct bar_config *bar, int output_i) {
+        sway_log(L_DEBUG, "Invoking swaybar for output %s[%d] and bar %s", output->name, output_i, bar->id);
+
+        size_t bufsize = 4;
+        char output_id[bufsize];
+        snprintf(output_id, bufsize, "%d", output_i);
+        output_id[bufsize-1] = 0;
+
+        char *const cmd[] = {
+                "swaybar",
+                "-b",
+                bar->id,
+                output_id,
+                NULL,
+        };
+
+        pid_t *pid = malloc(sizeof(pid_t));
+        *pid = fork();
+        if (*pid == 0) {
+                execvp(cmd[0], cmd);
+        }
+
+        // add swaybar pid to output
+        list_add(output->bar_pids, pid);
+}
+
+static void terminate_swaybars(list_t *pids) {
+        int i, ret;
+        pid_t *pid;
+        for (i = 0; i < pids->length; ++i) {
+                pid = pids->items[i];
+                ret = kill(*pid, SIGTERM);
+                if (ret != 0) {
+                        sway_log(L_ERROR, "Unable to terminate swaybar [pid: %d]", *pid);
+                } else {
+                        int status;
+                        waitpid(*pid, &status, 0);
+                }
+        }
+
+        // empty pids list
+        for (i = 0; i < pids->length; ++i) {
+                pid = pids->items[i];
+                list_del(pids, i);
+                free(pid);
+        }
+}
+
+void load_swaybars(swayc_t *output, int output_idx) {
+        // Check for bars
+        list_t *bars = create_list();
+        struct bar_config *bar = NULL;
+        int i;
+        for (i = 0; i < config->bars->length; ++i) {
+                bar = config->bars->items[i];
+                bool apply = false;
+                if (bar->outputs) {
+                        int j;
+                        for (j = 0; j < bar->outputs->length; ++j) {
+                                char *o = bar->outputs->items[j];
+                                if (strcmp(o, "*") || strcasecmp(o, output->name)) {
+                                        apply = true;
+                                        break;
+                                }
+                        }
+                } else {
+                        apply = true;
+                }
+                if (apply) {
+                        list_add(bars, bar);
+                }
+        }
+
+        // terminate swaybar processes previously spawned for this
+        // output.
+        terminate_swaybars(output->bar_pids);
+
+        for (i = 0; i < bars->length; ++i) {
+                bar = bars->items[i];
+                invoke_swaybar(output, bar, output_idx);
+        }
+
+        list_free(bars);
+}
+
 void apply_output_config(struct output_config *oc, swayc_t *output) {
         if (oc && oc->width > 0 && oc->height > 0) {
                 output->width = oc->width;
@@ -407,6 +495,16 @@ void apply_output_config(struct output_config *oc, swayc_t *output) {
 
         if (oc && oc->background) {
 
+                if (output->bg_pid != 0) {
+                        int ret = kill(output->bg_pid, SIGTERM);
+                        if (ret != 0) {
+                                sway_log(L_ERROR, "Unable to terminate swaybg [pid: %d]", output->bg_pid);
+                        } else {
+                                int status;
+                                waitpid(output->bg_pid, &status, 0);
+                        }
+                }
+
                 sway_log(L_DEBUG, "Setting background for output %d to %s", output_i, oc->background);
 
                 size_t bufsize = 4;
@@ -421,54 +519,15 @@ void apply_output_config(struct output_config *oc, swayc_t *output) {
                         oc->background_option,
                         NULL,
                 };
-                if (fork() == 0) {
-                        execvp(cmd[0], cmd);
-                }
-        }
-
-        // Check for a bar
-        struct bar_config *bar = NULL;
-        int i;
-        for (i = 0; i < config->bars->length; ++i) {
-                bar = config->bars->items[i];
-                bool apply = false;
-                if (bar->outputs) {
-                        int j;
-                        for (j = 0; j < bar->outputs->length; ++j) {
-                                char *o = bar->outputs->items[j];
-                                if (strcmp(o, "*") || strcasecmp(o, output->name)) {
-                                        apply = true;
-                                        break;
-                                }
-                        }
-                } else {
-                        apply = true;
-                }
-                if (apply) {
-                        break;
-                } else {
-                        bar = NULL;
-                }
-        }
-        if (bar) {
-                sway_log(L_DEBUG, "Invoking swaybar for output %s[%d] and bar %s", output->name, i, bar->id);
 
-                size_t bufsize = 4;
-                char output_id[bufsize];
-                snprintf(output_id, bufsize, "%d", output_i);
-                output_id[bufsize-1] = 0;
-
-                char *const cmd[] = {
-                        "swaybar",
-                        "-b",
-                        bar->id,
-                        output_id,
-                        NULL,
-                };
-                if (fork() == 0) {
+                output->bg_pid = fork();
+                if (output->bg_pid == 0) {
                         execvp(cmd[0], cmd);
                 }
         }
+
+        // load swaybars for output
+        load_swaybars(output, output_i);
 }
 
 char *do_var_replacement(char *str) {
diff --git a/sway/container.c b/sway/container.c
index 36056ff7..395eb04d 100644
--- a/sway/container.c
+++ b/sway/container.c
@@ -60,6 +60,9 @@ static void free_swayc(swayc_t *cont) {
         if (cont->app_id) {
                 free(cont->app_id);
         }
+        if (cont->bar_pids) {
+                free_flat_list(cont->bar_pids);
+        }
         free(cont);
 }
 
@@ -109,6 +112,8 @@ swayc_t *new_output(wlc_handle handle) {
         output->width = size->w;
         output->height = size->h;
         output->unmanaged = create_list();
+        output->bar_pids = create_list();
+        output->bg_pid = 0;
 
         apply_output_config(oc, output);
         add_child(&root_container, output);