platform/vfs.c: Redirect AppUser home dir

One less thing to require admin privileges.

platform/vfs.c

@@ -16,9 +16,17 @@
 static void vfs_slashify(wchar_t *path, size_t max_count);
 static HRESULT vfs_mkdir_rec(const wchar_t *path);
 static HRESULT vfs_path_hook(const wchar_t *src, wchar_t *dest, size_t *count);
+static HRESULT vfs_path_hook_nthome(
+        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);
 
+static wchar_t vfs_nthome_real[MAX_PATH];
+static const wchar_t vfs_nthome[] = L"C:\\Documents and Settings\\AppUser\\";
+static const size_t vfs_nthome_len = _countof(vfs_nthome) - 1;
+
 static const struct reg_hook_val vfs_reg_vals[] = {
     {
         .name   = L"AMFS",
@@ -35,6 +43,9 @@ static struct vfs_config vfs_config;
 
 HRESULT vfs_hook_init(const struct vfs_config *config)
 {
+    wchar_t temp[MAX_PATH];
+    size_t nthome_len;
+    DWORD home_ok;
     HRESULT hr;
 
     assert(config != NULL);
@@ -43,10 +54,24 @@ HRESULT vfs_hook_init(const struct vfs_config *config)
         return S_FALSE;
     }
 
+    home_ok = GetEnvironmentVariableW(
+            L"USERPROFILE",
+            vfs_nthome_real,
+            _countof(vfs_nthome_real));
+
+    if (!home_ok) {
+        hr = HRESULT_FROM_WIN32(GetLastError());
+        dprintf("Vfs: Failed to query %%USERPROFILE%% env var: %x\n",
+                (int) hr);
+
+        return hr;
+    }
+
     memcpy(&vfs_config, config, sizeof(*config));
 
     vfs_slashify(vfs_config.amfs, _countof(vfs_config.amfs));
     vfs_slashify(vfs_config.appdata, _countof(vfs_config.appdata));
+    vfs_slashify(vfs_nthome_real, _countof(vfs_nthome_real));
 
     hr = vfs_mkdir_rec(vfs_config.amfs);
 
@@ -66,12 +91,30 @@ HRESULT vfs_hook_init(const struct vfs_config *config)
         dprintf("Vfs: NOTE: SEGA Y: drive APPDATA, not Windows %%APPDATA%%.\n");
     }
 
+    /* Need to create the temp subdirectory, not just nthome itself */
+
+    nthome_len = wcslen(vfs_nthome_real);
+    wcscpy_s(temp, _countof(temp), vfs_nthome_real);
+    wcscpy_s(temp + nthome_len, _countof(temp) - nthome_len, L"temp");
+
+    hr = vfs_mkdir_rec(temp);
+
+    if (FAILED(hr)) {
+        dprintf("Vfs: Failed to create %S: %x\n", temp, (int) hr);
+    }
+
     hr = path_hook_push(vfs_path_hook);
 
     if (FAILED(hr)) {
         return hr;
     }
 
+    hr = path_hook_push(vfs_path_hook_nthome);
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
     hr = reg_hook_push_key(
             HKEY_LOCAL_MACHINE,
             L"SYSTEM\\SEGA\\SystemProperty\\mount",
@@ -206,6 +249,42 @@ static HRESULT vfs_path_hook(const wchar_t *src, wchar_t *dest, size_t *count)
     return S_OK;
 }
 
+static HRESULT vfs_path_hook_nthome(
+        const wchar_t *src,
+        wchar_t *dest,
+        size_t *count)
+{
+    size_t required;
+    size_t redir_len;
+
+    assert(src != NULL);
+    assert(count != NULL);
+
+    /* Case-insensitive check to see if src starts with vfs_nthome */
+
+    if (_wcsnicmp(src, vfs_nthome, vfs_nthome_len) != 0) {
+        return S_FALSE;
+    }
+
+    /* Cut off the matched prefix, add the replaced prefix, count NUL */
+
+    redir_len = wcslen(vfs_nthome_real);
+    required = wcslen(src) - vfs_nthome_len + redir_len + 1;
+
+    if (dest != NULL) {
+        if (required > *count) {
+            return HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER);
+        }
+
+        wcscpy_s(dest, *count, vfs_nthome_real);
+        wcscpy_s(dest + redir_len, *count - redir_len, src + vfs_nthome_len);
+    }
+
+    *count = required;
+
+    return S_OK;
+}
+
 static HRESULT vfs_reg_read_amfs(void *bytes, uint32_t *nbytes)
 {
     return reg_hook_read_wstr(bytes, nbytes, vfs_config.amfs);