platform/vfs.c: Add filesystem path redirectors

platform/meson.build

@@ -19,5 +19,7 @@ platform_lib = static_library(
         'pcbid.h',
         'platform.c',
         'platform.h',
+        'vfs.c',
+        'vfs.h',
     ],
 )

platform/platform.c

@@ -7,6 +7,7 @@
 #include "platform/hwmon.h"
 #include "platform/nusec.h"
 #include "platform/platform.h"
+#include "platform/vfs.h"
 
 HRESULT platform_hook_init_nu(
         const struct nu_config *cfg,
@@ -39,5 +40,11 @@ HRESULT platform_hook_init_nu(
         return hr;
     }
 
+    hr = vfs_hook_init(&cfg->vfs);
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
     return S_OK;
 }

platform/vfs.c

@@ -0,0 +1,217 @@
+#include <windows.h>
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "hooklib/path.h"
+#include "hooklib/reg.h"
+
+#include "platform/config.h"
+#include "platform/vfs.h"
+
+#include "util/dprintf.h"
+
+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_reg_read_amfs(void *bytes, uint32_t *nbytes);
+static HRESULT vfs_reg_read_appdata(void *bytes, uint32_t *nbytes);
+
+static const struct reg_hook_val vfs_reg_vals[] = {
+    {
+        .name   = L"AMFS",
+        .read   = vfs_reg_read_amfs,
+        .type   = REG_SZ,
+    }, {
+        .name   = L"APPDATA",
+        .read   = vfs_reg_read_appdata,
+        .type   = REG_SZ
+    },
+};
+
+static struct vfs_config vfs_config;
+
+HRESULT vfs_hook_init(const struct vfs_config *config)
+{
+    HRESULT hr;
+
+    assert(config != NULL);
+
+    if (!config->enable) {
+        return S_FALSE;
+    }
+
+    memcpy(&vfs_config, config, sizeof(*config));
+
+    vfs_slashify(vfs_config.amfs, _countof(vfs_config.amfs));
+    vfs_slashify(vfs_config.appdata, _countof(vfs_config.appdata));
+
+    hr = vfs_mkdir_rec(vfs_config.amfs);
+
+    if (FAILED(hr)) {
+        dprintf("Vfs: Failed to create AMFS dir %S: %x\n",
+                config->amfs,
+                (int) hr);
+    }
+
+    hr = vfs_mkdir_rec(vfs_config.appdata);
+
+    if (FAILED(hr)) {
+        dprintf("Vfs: Failed to create APPDATA dir %S: %x\n",
+                config->appdata,
+                (int) hr);
+
+        dprintf("Vfs: NOTE: SEGA Y: drive APPDATA, not Windows %%APPDATA%%.\n");
+    }
+
+    hr = path_hook_push(vfs_path_hook);
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
+    hr = reg_hook_push_key(
+            HKEY_LOCAL_MACHINE,
+            L"SYSTEM\\SEGA\\SystemProperty\\mount",
+            vfs_reg_vals,
+            _countof(vfs_reg_vals));
+
+    if (FAILED(hr)) {
+        return hr;
+    }
+
+    return S_OK;
+}
+
+static void vfs_slashify(wchar_t *path, size_t max_count)
+{
+    size_t count;
+
+    assert(path != NULL);
+
+    count = wcslen(path);
+
+    if (path[count - 1] == L'\\' || path[count - 1] == L'/') {
+        return;
+    }
+
+    if (count + 2 > max_count) {
+        abort();
+    }
+
+    path[count + 0] = L'\\';
+    path[count + 1] = L'\0';
+}
+
+static HRESULT vfs_mkdir_rec(const wchar_t *path)
+{
+    wchar_t *copy;
+    wchar_t *pos;
+    wchar_t wc;
+    HRESULT hr;
+    DWORD attr;
+    BOOL ok;
+
+    assert(path != NULL);
+
+    copy = _wcsdup(path);
+
+    if (copy == NULL) {
+        hr = HRESULT_FROM_WIN32(ERROR_OUTOFMEMORY);
+
+        goto end;
+    }
+
+    pos = copy;
+
+    do {
+        wc = *pos;
+
+        if (wc == L'\0' || wc == L'/' || wc == L'\\') {
+            *pos = L'\0';
+            attr = GetFileAttributesW(copy);
+
+            if (attr == INVALID_FILE_ATTRIBUTES) {
+                ok = CreateDirectoryW(copy, NULL);
+
+                if (!ok) {
+                    hr = HRESULT_FROM_WIN32(GetLastError());
+
+                    goto end;
+                }
+            }
+
+            *pos = wc;
+        }
+
+        pos++;
+    } while (wc != L'\0');
+
+    hr = S_OK;
+
+end:
+    free(copy);
+
+    return hr;
+}
+
+static HRESULT vfs_path_hook(const wchar_t *src, wchar_t *dest, size_t *count)
+{
+    const wchar_t *redir;
+    size_t required;
+    size_t redir_len;
+
+    assert(src != NULL);
+    assert(count != NULL);
+
+    if (src[0] == L'\0' || src[1] != L':' || src[2] != L'\\') {
+        return S_FALSE;
+    }
+
+    switch (src[0]) {
+    case L'e':
+    case L'E':
+        redir = vfs_config.amfs;
+
+        break;
+
+    case L'y':
+    case L'Y':
+        redir = vfs_config.appdata;
+
+        break;
+
+    default:
+        return S_FALSE;
+    }
+
+    /* Cut off E:\ prefix, replace with redir path, count NUL terminator */
+
+    redir_len = wcslen(redir);
+    required = wcslen(src) - 3 + redir_len + 1;
+
+    if (dest != NULL) {
+        if (required > *count) {
+            return HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER);
+        }
+
+        wcscpy_s(dest, *count, redir);
+        wcscpy_s(dest + redir_len, *count - redir_len, src + 3);
+    }
+
+    *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);
+}
+
+static HRESULT vfs_reg_read_appdata(void *bytes, uint32_t *nbytes)
+{
+    return reg_hook_read_wstr(bytes, nbytes, vfs_config.appdata);
+}

platform/vfs.h

@@ -0,0 +1,7 @@
+#pragma once
+
+#include <windows.h>
+
+#include "platform/config.h"
+
+HRESULT vfs_hook_init(const struct vfs_config *config);