(WiiU) Core loading support

This commit re-adds core loading support, now compatible with Tiramisu and
Aroma; using a libmocha feature added in those CFWs. Note that this does NOT
work under Haxchi FW, non-payload Mocha versions, etc. RetroArch now requires
either Tiramisu or Aroma on Wii U.

The overall strategy is to make the path of the core to be loaded relative to
the SD card root, pass this off to Mocha, then switch titles to the wrapper
title (usually Health and Safety). In order to pass arguments, sysapp is used,
with a little extra logic (since sysapp passes a blob of arbitrary bytes) to
emulate argc/argv.

Makefile.wiiu

@@ -41,11 +41,14 @@ OBJ += wiiu/system/exception_handler.o
 OBJ += wiiu/system/missing_libc_functions.o
 
 ifeq ($(SALAMANDER_BUILD),1)
-   DEFINES += -DRARCH_CONSOLE -DIS_SALAMANDER
+   DEFINES += -DRARCH_CONSOLE -DIS_SALAMANDER -DHAVE_LIBMOCHA
+
+   INCDIRS += -Ideps/libmocha/include
 
    OBJ += frontend/frontend_salamander.o
    OBJ += frontend/frontend_driver.o
    OBJ += frontend/drivers/platform_wiiu.o
+   OBJ += deps/libmocha/source/utils.o
    OBJ += libretro-common/encodings/encoding_utf.o
    OBJ += libretro-common/compat/compat_strcasestr.o
    OBJ += libretro-common/compat/fopen_utf8.o

frontend/drivers/platform_wiiu.c

@@ -84,9 +84,11 @@
  */
 
 #ifndef IS_SALAMANDER
+static enum frontend_fork wiiu_fork_mode = FRONTEND_FORK_NONE;
 static bool have_libfat_usb = false;
 static bool have_libfat_sdcard = false;
 #endif
+static bool in_exec = false;
 
 static bool exists(char *path)
 {
@@ -226,18 +228,154 @@ static int frontend_wiiu_parse_drive_list(void *data, bool load_content)
    return 0;
 }
 
+static void frontend_wiiu_exec(const char *path, bool should_load_content)
+{
+   /* goal: make one big buffer with all the argv's, seperated by NUL. we can
+    * then pass this thru sysapp! */
+   char *argv_buf;
+   size_t n, argv_len = strlen(path) + 1; /* argv[0] plus null */
+
+#ifndef IS_SALAMANDER
+   const char *content = path_get(RARCH_PATH_CONTENT);
+   const char *content_args[2] = {content, NULL};
+#ifdef HAVE_NETWORKING
+   const char *netplay_args[NETPLAY_FORK_MAX_ARGS];
+#endif
+#endif
+   /* args will select between content_args, netplay_args, or no args (default) */
+   const char **args = NULL;
+
+   /* and some other stuff (C89) */
+   MochaRPXLoadInfo load_info = {0};
+   MochaUtilsStatus ret;
+   SYSStandardArgsIn std_args = {0};
+
+#ifndef IS_SALAMANDER
+   if (should_load_content)
+   {
+#ifdef HAVE_NETWORKING
+      if (netplay_driver_ctl(RARCH_NETPLAY_CTL_GET_FORK_ARGS,
+            (void *) netplay_args))
+      {
+         const char **cur_arg = netplay_args;
+
+         do
+            argv_len += strnlen(*cur_arg, PATH_MAX_LENGTH) + 1;
+         while (*(++cur_arg));
+
+         args = netplay_args;
+      } else
+#endif
+      if (!string_is_empty(content))
+      {
+         argv_len += strnlen(content, PATH_MAX_LENGTH) + 1;
+         args = content_args;
+      }
+   }
+#endif
+
+   argv_buf = malloc(argv_len);
+   argv_buf[0] = '\0';
+
+   n = strlcpy(argv_buf, path, argv_len);
+   n++; /* leave room for the NUL */
+   if (args)
+   {
+      const char **cur_arg = args;
+      do
+      {
+         n += strlcpy(argv_buf + n, *cur_arg, argv_len - n);
+         n++;
+      } while (*(++cur_arg));
+   }
+
+   if (string_starts_with(path, "fs:/vol/external01/"))
+      path_relative_to(load_info.path, path, "fs:/vol/external01/", sizeof(load_info.path));
+   else if (string_starts_with(path, "sd:/"))
+      path_relative_to(load_info.path, path, "sd:/", sizeof(load_info.path));
+   else goto cleanup; /* bail if not on the SD card */
+
+   /* Mocha might not be init'd (Salamander) */
+   if (Mocha_InitLibrary() != MOCHA_RESULT_SUCCESS)
+      goto cleanup;
+
+   load_info.target = LOAD_RPX_TARGET_SD_CARD;
+   ret = Mocha_PrepareRPXLaunch(&load_info);
+   if (ret != MOCHA_RESULT_SUCCESS)
+      goto cleanup;
+
+   std_args.argString = argv_buf;
+   std_args.size = argv_len;
+   ret = Mocha_LaunchHomebrewWrapperEx(&std_args);
+   if (ret != MOCHA_RESULT_SUCCESS)
+   {
+      MochaRPXLoadInfo load_info_revert;
+      load_info_revert.target = LOAD_RPX_TARGET_EXTRA_REVERT_PREPARE;
+      Mocha_PrepareRPXLaunch(&load_info_revert);
+      goto cleanup;
+   }
+
+   in_exec = true;
+
+   cleanup:
+   free(argv_buf);
+   argv_buf = NULL;
+}
+
+static void frontend_wiiu_exitspawn(char *s, size_t len, char *args)
+{
+   bool should_load_content = false;
+#ifndef IS_SALAMANDER
+   if (wiiu_fork_mode == FRONTEND_FORK_NONE)
+      return;
+
+   switch (wiiu_fork_mode)
+   {
+      case FRONTEND_FORK_CORE_WITH_ARGS:
+         should_load_content = true;
+         break;
+      default:
+         break;
+   }
+#endif
+   frontend_wiiu_exec(s, should_load_content);
+}
+
+#ifndef IS_SALAMANDER
+static bool frontend_wiiu_set_fork(enum frontend_fork fork_mode)
+{
+   switch (fork_mode)
+   {
+      case FRONTEND_FORK_CORE:
+      case FRONTEND_FORK_CORE_WITH_ARGS:
+         wiiu_fork_mode = fork_mode;
+         break;
+      case FRONTEND_FORK_RESTART:
+         /* NOTE: We don't implement Salamander, so just turn
+          * this into FRONTEND_FORK_CORE. */
+         wiiu_fork_mode = FRONTEND_FORK_CORE;
+         break;
+      case FRONTEND_FORK_NONE:
+      default:
+         return false;
+   }
+
+   return true;
+}
+#endif
+
 frontend_ctx_driver_t frontend_ctx_wiiu =
 {
    frontend_wiiu_get_env_settings,
    frontend_wiiu_init,
    frontend_wiiu_deinit,
-   NULL,                         /* exitspawn */
+   frontend_wiiu_exitspawn,
    NULL,                         /* process_args */
-   NULL,                         /* exec */
+   frontend_wiiu_exec,
 #ifdef IS_SALAMANDER
    NULL,                         /* set_fork */
 #else
-   NULL,                         /* set_fork */
+   frontend_wiiu_set_fork,
 #endif
    frontend_wiiu_shutdown,
    NULL,                         /* get_name */
@@ -272,6 +410,7 @@ frontend_ctx_driver_t frontend_ctx_wiiu =
 /* main() and its supporting functions */
 
 static void main_setup(void);
+static void get_arguments(int *argc, char ***argv);
 #ifndef IS_SALAMANDER
 static void main_loop(void);
 #endif
@@ -291,6 +430,7 @@ int main(int argc, char **argv)
 {
    proc_setup();
    main_setup();
+   get_arguments(&argc, &argv);
 
 #ifdef IS_SALAMANDER
    int salamander_main(int argc, char **argv);
@@ -328,9 +468,31 @@ static void main_teardown(void)
    memoryRelease();
 }
 
+// https://github.com/devkitPro/wut/blob/7d9fa9e416bffbcd747f1a8e5701fd6342f9bc3d/libraries/libwhb/src/proc.c
+
+#define HBL_TITLE_ID (0x0005000013374842)
+#define MII_MAKER_JPN_TITLE_ID (0x000500101004A000)
+#define MII_MAKER_USA_TITLE_ID (0x000500101004A100)
+#define MII_MAKER_EUR_TITLE_ID (0x000500101004A200)
+
+static bool in_hbl = false;
 static bool in_aroma = false;
+
 static void proc_setup(void)
 {
+   uint64_t titleID = OSGetTitleID();
+
+   // Homebrew Launcher does not like the standard ProcUI application loop, sad!
+   if (titleID == HBL_TITLE_ID ||
+       titleID == MII_MAKER_JPN_TITLE_ID ||
+       titleID == MII_MAKER_USA_TITLE_ID ||
+       titleID == MII_MAKER_EUR_TITLE_ID)
+   {
+      // Important: OSEnableHomeButtonMenu must come before ProcUIInitEx.
+      OSEnableHomeButtonMenu(FALSE);
+      in_hbl = TRUE;
+   }
+
    /* Detect Aroma explicitly (it's possible to run under H&S while using Tiramisu) */
    OSDynLoad_Module rpxModule;
    if (OSDynLoad_Acquire("homebrew_rpx_loader", &rpxModule) == OS_DYNLOAD_OK)
@@ -344,6 +506,29 @@ static void proc_setup(void)
 
 static void proc_exit(void)
 {
+   /* If we're doing a normal exit while running under HBL, we must SYSRelaunchTitle.
+    * If we're in an exec (i.e. launching mocha homebrew wrapper) we must *not* do that. yay! */
+   if (in_hbl && !in_exec)
+      SYSRelaunchTitle(0, NULL);
+
+   /* Similar deal for Aroma, but exit to menu. */
+   if (!in_hbl && !in_exec)
+      SYSLaunchMenu();
+
+   /* Now just tell the OS that we really are ok to exit */
+   if (!ProcUIInShutdown())
+   {
+      for (;;)
+      {
+         ProcUIStatus status;
+         status = ProcUIProcessMessages(TRUE);
+         if (status == PROCUI_STATUS_EXITING)
+            break;
+         else if (status == PROCUI_STATUS_RELEASE_FOREGROUND)
+            ProcUIDrawDoneRelease();
+      }
+   }
+
    ProcUIShutdown();
 }
 
@@ -352,6 +537,54 @@ static void proc_save_callback(void)
    OSSavesDone_ReadyToRelease();
 }
 
+static void sysapp_arg_cb(SYSDeserializeArg *arg, void *usr)
+{
+   SYSStandardArgs *std_args = (SYSStandardArgs *) usr;
+
+   if (_SYSDeserializeStandardArg(arg, std_args))
+      return;
+
+   if (strcmp(arg->argName, "sys:pack") == 0)
+   {
+      // Recurse
+      SYSDeserializeSysArgsFromBlock(arg->data, arg->size, sysapp_arg_cb, usr);
+      return;
+   }
+}
+
+static void get_arguments(int *argc, char ***argv)
+{
+#ifdef HAVE_NETWORKING
+   static char *_argv[1 + NETPLAY_FORK_MAX_ARGS];
+#else
+   static char* _argv[2];
+#endif
+   int _argc = 0;
+   SYSStandardArgs std_args = {0};
+
+   /* we could do something more rich with the content path and things here -
+    * but since there's not a great way to actually pass that info along to RA,
+    * just emulate argc/argv */
+   SYSDeserializeSysArgs(sysapp_arg_cb, &std_args);
+
+   char *argv_buf = std_args.anchorData;
+   size_t argv_len = std_args.anchorSize;
+   if (!argv_buf || argv_len == 0)
+      return;
+
+   size_t n = 0;
+   while (n < argv_len && _argc < ARRAY_SIZE(_argv))
+   {
+      char *s = argv_buf + n;
+      _argv[_argc++] = s;
+      n += strlen(s);
+      n++; /* skip the null */
+   }
+
+   *argc = _argc;
+   *argv = _argv;
+}
+
 #ifndef IS_SALAMANDER
 static bool swap_is_pending(void *start_time)
 {