From 2c28605d0d0d2bb8f90844c70f435f904037a5de Mon Sep 17 00:00:00 2001
From: Travis Geiselbrecht <travisg@gmail.com>
Date: Tue, 25 May 2021 23:04:41 -0700
Subject: [PATCH] [app] add a standalone routine and a command line app start
 routine

---
 app/app.c         | 82 +++++++++++++++++++++++++++++++++++++++++++----
 app/include/app.h |  9 +++++-
 2 files changed, 83 insertions(+), 8 deletions(-)

diff --git a/app/app.c b/app/app.c
index 789f3d48..e436d748 100644
--- a/app/app.c
+++ b/app/app.c
@@ -5,14 +5,18 @@
  * license that can be found in the LICENSE file or at
  * https://opensource.org/licenses/MIT
  */
+#include "app.h"
+
 #include <stdio.h>
-#include <app.h>
+#include <string.h>
+#include <lk/err.h>
+#include <lk/console_cmd.h>
 #include <kernel/thread.h>
 
 extern const struct app_descriptor __start_apps __WEAK;
 extern const struct app_descriptor __stop_apps __WEAK;
 
-static void start_app(const struct app_descriptor *app);
+static void start_app(const struct app_descriptor *app, bool detach);
 
 /* one time setup */
 void apps_init(void) {
@@ -26,8 +30,8 @@ void apps_init(void) {
 
     /* start any that want to start on boot */
     for (app = &__start_apps; app != &__stop_apps; app++) {
-        if (app->entry && (app->flags & APP_FLAG_DONT_START_ON_BOOT) == 0) {
-            start_app(app);
+        if (app->entry && (app->flags & APP_FLAG_NO_AUTOSTART) == 0) {
+            start_app(app, true);
         }
     }
 }
@@ -40,12 +44,76 @@ static int app_thread_entry(void *arg) {
     return 0;
 }
 
-static void start_app(const struct app_descriptor *app) {
+static void start_app(const struct app_descriptor *app, bool detach) {
     uint32_t stack_size = (app->flags & APP_FLAG_CUSTOM_STACK_SIZE) ? app->stack_size : DEFAULT_STACK_SIZE;
 
     printf("starting app %s\n", app->name);
     thread_t *t = thread_create(app->name, &app_thread_entry, (void *)app, DEFAULT_PRIORITY, stack_size);
-    thread_detach(t);
-    thread_resume(t);
+    if (detach) {
+        thread_detach(t);
+        thread_resume(t);
+    } else {
+        thread_resume(t);
+        thread_join(t, NULL, INFINITE_TIME);
+    }
 }
 
+status_t app_start_by_name(const char *name, bool detached) {
+    const struct app_descriptor *app;
+
+    /* find the app and call it */
+    for (app = &__start_apps; app != &__stop_apps; app++) {
+        if (!strcmp(app->name, name)) {
+            start_app(app, detached);
+            return NO_ERROR;
+        }
+    }
+
+    return ERR_NOT_FOUND;
+}
+
+static void list_apps(void) {
+    const struct app_descriptor *app;
+
+    for (app = &__start_apps; app != &__stop_apps; app++) {
+        printf("%s\n", app->name);
+    }
+}
+
+static int cmd_app(int argc, const console_cmd_args *argv) {
+    if (argc == 1) {
+usage:
+        printf("%s subcommands:\n", argv[0].str);
+        printf("%s list         : list apps compiled into the system\n", argv[0].str);
+        printf("%s start <name> : run app\n", argv[0].str);
+        return ERR_INVALID_ARGS;
+    } else if (!strcmp(argv[1].str, "list")) {
+        list_apps();
+    } else if (!strcmp(argv[1].str, "start")) {
+        if (argc <= 2) {
+            printf("not enough args\n");
+            goto usage;
+        }
+
+        app_start_by_name(argv[2].str, false);
+    } else {
+        printf("unknown subcommand\n");
+        goto usage;
+    }
+
+    return NO_ERROR;
+}
+
+static int cmd_start(int argc, const console_cmd_args *argv) {
+    if (argc == 1) {
+        printf("not enough args\n");
+        return ERR_INVALID_ARGS;
+    }
+
+    return app_start_by_name(argv[1].str, false);
+}
+
+STATIC_COMMAND_START
+STATIC_COMMAND("app", "commands to operate on apps", &cmd_app)
+STATIC_COMMAND("start", "shortcut for app start", &cmd_start)
+STATIC_COMMAND_END(app);
diff --git a/app/include/app.h b/app/include/app.h
index ded9cb0b..19ac3b2e 100644
--- a/app/include/app.h
+++ b/app/include/app.h
@@ -9,19 +9,26 @@
 
 #include <stddef.h>
 #include <lk/compiler.h>
+#include <stdbool.h>
+#include <sys/types.h>
 
 __BEGIN_CDECLS
 
 /* app support api */
 void apps_init(void); /* one time setup */
 
+/* start an app by name.
+ * optionally start detached or wait for it to complete.
+ */
+status_t app_start_by_name(const char *name, bool detached);
+
 /* app entry point */
 struct app_descriptor;
 typedef void (*app_init)(const struct app_descriptor *);
 typedef void (*app_entry)(const struct app_descriptor *, void *args);
 
 /* app startup flags */
-#define APP_FLAG_DONT_START_ON_BOOT 0x1
+#define APP_FLAG_NO_AUTOSTART 0x1
 #define APP_FLAG_CUSTOM_STACK_SIZE 0x2
 
 /* each app needs to define one of these to define its startup conditions */