APMv3: add hook (#73)

This adds support for APMv3 I/O, menus and the launcher.

* Added a apm3hook dll and I/O based on the usual layout.
* Added C:\Mount\Apm to vfs.
* Added the relevant .dlls to unityhook.
* Added a hook for apmmount.dll that uses `CreateDosDevice` to mount decrypted data to the locations the launcher and games expect files to be. This will conflict with anything that is already at W:\ and X:\, but I do not have better solutions for this.
* `launch.bat` is a bit more involved as it simulates the launcher loop. It can be broken by alt+f4ing or closing the launcher with "X".
* An extra export was added, so rundll32 can be used to get rid of the dosdevices after the launcher was killed.
* Since all the games do everything via `X:\lib\apm.dll`, no game hooks were needed in testing, therefore, `game.bat` files can be used as is.
* Path hooks are applied correctly, so you can go correctly between games, launcher, sub system test mode and game test modes.

A setup guide (some stuff specific to my server) can be found here:
https://gmg.hopto.org:82/gmg/wiki/index.php/All.Net_P-ras_Multi_Menu

Tested with the 2 APM sample apps, Blazblue, Puyo, Guilty Gear and some weird unity puzzle game whose name I forgot.

![Apmv3System_yLRityJVpm.png](/attachments/3d645e71-81e6-42e6-acd4-63c537cda59e)
![puyoe_hJNhnJGFnd.png](/attachments/01664049-71fe-4c38-9c99-39649ab21e56)

Reviewed-on: TeamTofuShop/segatools#73
Co-authored-by: kyoubate-haruka <46010460+kyoubate-haruka@users.noreply.github.com>
Co-committed-by: kyoubate-haruka <46010460+kyoubate-haruka@users.noreply.github.com>

common/platform/vfs.c

@@ -31,6 +31,10 @@ static HRESULT vfs_path_hook_option(
         const wchar_t *src,
         wchar_t *dest,
         size_t *count);
+static HRESULT vfs_path_hook_apm(
+        const wchar_t *src,
+        wchar_t *dest,
+        size_t *count);
 static HRESULT vfs_reg_read_amfs(void *bytes, uint32_t *nbytes);
 static HRESULT vfs_reg_read_appdata(void *bytes, uint32_t *nbytes);
 
@@ -64,6 +68,9 @@ static const size_t vfs_w10home_len = _countof(vfs_w10home) - 1;
 static const wchar_t vfs_option[] = L"C:\\Mount\\Option";
 static const size_t vfs_option_len = _countof(vfs_option) - 1;
 
+static const wchar_t vfs_apm3[] = L"C:\\Mount\\Apm";
+static const size_t vfs_apm3_len = _countof(vfs_apm3) - 1;
+
 static const struct reg_hook_val vfs_reg_vals[] = {
     {
         .name   = L"AMFS",
@@ -199,6 +206,11 @@ HRESULT vfs_hook_init(const struct vfs_config *config, const char* game_id)
     if (vfs_config.option[0] != L'\0') {
         hr = path_hook_push(vfs_path_hook_option);
 
+        if (FAILED(hr)) {
+            return hr;
+        }
+        hr = path_hook_push(vfs_path_hook_apm);
+
         if (FAILED(hr)) {
             return hr;
         }
@@ -514,6 +526,53 @@ static HRESULT vfs_path_hook_option(
     return S_OK;
 }
 
+static HRESULT vfs_path_hook_apm(
+        const wchar_t *src,
+        wchar_t *dest,
+        size_t *count)
+{
+    size_t required;
+    size_t redir_len;
+    size_t shift;
+
+    assert(src != NULL);
+    assert(count != NULL);
+
+    /* Case-insensitive check to see if src starts with vfs_apm */
+
+    if (path_compare_w(src, vfs_apm3, vfs_apm3_len) != 0) {
+        return S_FALSE;
+    }
+
+    /* Check if the character after vfs_nthome is a separator or the end of
+       the string */
+
+    if (!path_is_separator_w(src[vfs_apm3_len]) &&
+            src[vfs_apm3_len] != L'\0')
+    {
+        return S_FALSE;
+    }
+
+    /* Cut off the matched <prefix>\, add the replaced prefix, count NUL */
+
+    shift = path_is_separator_w(src[vfs_apm3_len]) ? 1 : 0;
+    redir_len = wcslen(vfs_config.option);
+    required = wcslen(src) - vfs_apm3_len - shift + redir_len + 1;
+
+    if (dest != NULL) {
+        if (required > *count) {
+            return HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER);
+        }
+
+        wcscpy_s(dest, *count, vfs_config.option);
+        wcscpy_s(dest + redir_len, *count - redir_len, src + vfs_apm3_len + shift);
+    }
+
+    *count = required;
+
+    return S_OK;
+}
+
 static HRESULT vfs_reg_read_amfs(void *bytes, uint32_t *nbytes)
 {
     return reg_hook_read_wstr(bytes, nbytes, L"E:\\");