Support basic loading a .rpx from a bundle, change path of installer. OSFatal when the installer is missing on the sd card

Dockerfile

@@ -1,3 +1,5 @@
 FROM wiiuenv/devkitppc:20211106
 
+COPY --from=wiiuenv/libromfs_wiiu:20210924 /artifacts $DEVKITPRO
+
 WORKDIR project

Makefile

@@ -36,13 +36,13 @@ CXXFLAGS	:= $(CFLAGS)
 ASFLAGS	:=	-g $(ARCH) -mregnames
 LDFLAGS	=	-g $(ARCH) $(RPXSPECS) --entry=_start -Wl,-Map,$(notdir $*.map)
 
-LIBS	:= -lwut
+LIBS	:= -lwut -lromfs
 
 #-------------------------------------------------------------------------------
 # list of directories containing libraries, this must be the top level
 # containing include and lib
 #-------------------------------------------------------------------------------
-LIBDIRS	:= $(PORTLIBS) $(WUT_ROOT)
+LIBDIRS	:= $(PORTLIBS) $(WUT_ROOT) $(WUT_ROOT)/usr
 
 
 #-------------------------------------------------------------------------------

source/main.cpp

@@ -1,9 +1,15 @@
+#include <string>
+#include <sys/types.h>
+#include <dirent.h>
 #include <string.h>
 #include <coreinit/title.h>
 #include <sysapp/title.h>
 #include <sysapp/launch.h>
 #include <coreinit/ios.h>
 #include <coreinit/cache.h>
+#include <coreinit/debug.h>
+
+#include <romfs_dev.h>
 
 typedef struct __attribute((packed)) {
     uint32_t command;
@@ -16,7 +22,53 @@ typedef struct __attribute((packed)) {
 extern "C" void _SYSLaunchTitleWithStdArgsInNoSplash(uint64_t, int);
 extern "C" void OSRestartGame();
 
+bool StringEndsWith(const std::string &a, const std::string &b) {
+    if (b.size() > a.size())
+        return false;
+    return std::equal(a.begin() + a.size() - b.size(), a.end(), b.begin());
+}
+
+int32_t getRPXInfoForPath(const std::string &path, romfs_fileInfo *info) {
+    if (romfsMount("rcc", path.c_str(), RomfsSource_FileDescriptor_CafeOS) < 0) {
+        return -1;
+    }
+    DIR *dir;
+    struct dirent *entry;
+
+    if (!(dir = opendir("rcc:/code/"))) {
+        romfsUnmount("rcc");
+        return -2;
+    }
+    bool found = false;
+    int res = -3;
+    while ((entry = readdir(dir)) != nullptr) {
+        if (StringEndsWith(entry->d_name, ".rpx")) {
+            if (romfsGetFileInfoPerPath("rcc", (std::string("code/") + entry->d_name).c_str(), info) >= 0) {
+                found = true;
+                res = 0;
+            }
+            break;
+        }
+    }
+
+    closedir(dir);
+
+    romfsUnmount("rcc");
+
+    if (!found) {
+        return -4;
+    }
+    return res;
+}
+
 int main(int argc, char **argv) {    
+    std::string bundle_path = "wiiu/apps/PayloadLoaderInstaller.wuhb";
+    std::string completePath = std::string("/vol/external01/") + bundle_path;
+    
+    if (fopen(completePath.c_str(), "r") == NULL) {
+        OSFatal("\"sd:/wiiu/apps/PayloadLoaderInstaller.wuhb\" is missing on the sd card");;
+    }
+        
     LOAD_REQUEST request;
     memset(&request, 0, sizeof(request));
 
@@ -26,7 +78,16 @@ int main(int argc, char **argv) {
     request.fileoffset = 0; //    
     request.path[0] = '\0';
     
-    strncat(request.path, "/wiiu/apps/payload_loader_installer.rpx", sizeof(request.path) - 1);
+
+    romfs_fileInfo info;
+    int res = getRPXInfoForPath(completePath, &info);
+    
+    if (res >= 0) {
+        request.filesize = ((uint32_t *) &info.length)[1];
+        request.fileoffset = ((uint32_t *) &info.offset)[1];
+    }
+
+    strncat(request.path, bundle_path.c_str() , sizeof(request.path) - 1);
     DCFlushRange(&request, sizeof(LOAD_REQUEST));
 
     int mcpFd = IOS_Open("/dev/mcp", (IOSOpenMode) 0);