[glib: 2/5] Fix dbus process autolaunch with static build on Windows

[Philip Withnall <pwithnall src gnome org>]

commit 38abadab3d0b3581a1a6485106cbf1ad6479c363
Author: Loic Le Page <llepage fluendo com>
Date:   Mon Jan 10 20:44:45 2022 +0100

    Fix dbus process autolaunch with static build on Windows
    
    On Windows, dbus is launched by spawning the gdbus.exe executable on
    demand from the gio module. When linked dynamically, the executable
    path is guessed relatively to the gio DLL path. But when linked
    statically, the only reference path available is the current
    executable path. In this case, gdbus.exe is not necessarily in the same
    folder as the current executable.
    
    This patch solves the issue using the same algorithm as the one used
    with process spawning in glib core source code two commits above.

 gio/gdbusprivate.c | 135 +++++++++++++++++++++++++++++------------------------
 1 file changed, 74 insertions(+), 61 deletions(-)
---
diff --git a/gio/gdbusprivate.c b/gio/gdbusprivate.c
index 041fab7a8..0b8630ab2 100644
--- a/gio/gdbusprivate.c
+++ b/gio/gdbusprivate.c
@@ -23,27 +23,28 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "giotypes.h"
-#include "gioenumtypes.h"
-#include "gsocket.h"
 #include "gdbusauthobserver.h"
-#include "gdbusprivate.h"
-#include "gdbusmessage.h"
 #include "gdbusconnection.h"
-#include "gdbusproxy.h"
+#include "gdbusdaemon.h"
 #include "gdbuserror.h"
 #include "gdbusintrospection.h"
-#include "gdbusdaemon.h"
-#include "giomodule-priv.h"
-#include "gtask.h"
+#include "gdbusmessage.h"
+#include "gdbusprivate.h"
+#include "gdbusproxy.h"
 #include "ginputstream.h"
-#include "gmemoryinputstream.h"
+#include "gioenumtypes.h"
+#include "giomodule-priv.h"
 #include "giostream.h"
+#include "giotypes.h"
+#include "glib-private.h"
 #include "glib/gstdio.h"
+#include "gmemoryinputstream.h"
+#include "gsocket.h"
 #include "gsocketaddress.h"
-#include "gsocketcontrolmessage.h"
 #include "gsocketconnection.h"
+#include "gsocketcontrolmessage.h"
 #include "gsocketoutputstream.h"
+#include "gtask.h"
 
 #ifdef G_OS_UNIX
 #include "gunixfdmessage.h"
@@ -2275,6 +2276,26 @@ g_win32_run_session_bus (void* hwnd, void* hinst, const char* cmdline, int cmdsh
 
 static gboolean autolaunch_binary_absent = FALSE;
 
+static wchar_t *
+find_dbus_process_path (void)
+{
+  wchar_t *dbus_path;
+  gchar *exe_path = GLIB_PRIVATE_CALL (g_win32_find_helper_executable_path) ("gdbus.exe", 
_g_io_win32_get_module ());
+  dbus_path = g_utf8_to_utf16 (exe_path, -1, NULL, NULL, NULL);
+  g_free (exe_path);
+
+  if (dbus_path == NULL)
+    return NULL;
+
+  if (GetFileAttributesW (dbus_path) == INVALID_FILE_ATTRIBUTES)
+    {
+      g_free (dbus_path);
+      return NULL;
+    }
+
+  return dbus_path;
+}
+
 gchar *
 _g_dbus_win32_get_session_address_dbus_launch (GError **error)
 {
@@ -2292,61 +2313,53 @@ _g_dbus_win32_get_session_address_dbus_launch (GError **error)
 
   if (address == NULL && !autolaunch_binary_absent)
     {
-      wchar_t gio_path[MAX_PATH + 2] = { 0 };
-      int gio_path_len = GetModuleFileNameW (_g_io_win32_get_module (), gio_path, MAX_PATH + 1);
-
-      /* The <= MAX_PATH check prevents truncated path usage */
-      if (gio_path_len > 0 && gio_path_len <= MAX_PATH)
-       {
-         PROCESS_INFORMATION pi = { 0 };
-         STARTUPINFOW si = { 0 };
-         BOOL res = FALSE;
-         wchar_t exe_path[MAX_PATH + 100] = { 0 };
-         /* calculate index of first char of dll file name inside full path */
-         int gio_name_index = gio_path_len;
-         for (; gio_name_index > 0; --gio_name_index)
-         {
-           wchar_t prev_char = gio_path[gio_name_index - 1];
-           if (prev_char == L'\\' || prev_char == L'/')
-             break;
-         }
-         gio_path[gio_name_index] = L'\0';
-         wcscpy (exe_path, gio_path);
-         wcscat (exe_path, L"\\gdbus.exe");
-
-         if (GetFileAttributesW (exe_path) == INVALID_FILE_ATTRIBUTES)
-           {
-             /* warning won't be raised another time
-              * since autolaunch_binary_absent would be already set.
-              */
-             autolaunch_binary_absent = TRUE;
-             g_warning ("win32 session dbus binary not found: %S", exe_path );
-           }
-         else
-           {
-             wchar_t args[MAX_PATH*2 + 100] = { 0 };
-             wcscpy (args, L"\"");
-             wcscat (args, exe_path);
-             wcscat (args, L"\" ");
+      wchar_t *dbus_path = find_dbus_process_path ();
+      if (dbus_path == NULL)
+        {
+          /* warning won't be raised another time
+           * since autolaunch_binary_absent would be already set.
+           */
+          autolaunch_binary_absent = TRUE;
+          g_warning ("win32 session dbus binary not found");
+        }
+      else
+        {
+          PROCESS_INFORMATION pi = { 0 };
+          STARTUPINFOW si = { 0 };
+          BOOL res = FALSE;
+          wchar_t args[MAX_PATH * 2 + 100] = { 0 };
+          wchar_t working_dir[MAX_PATH + 2] = { 0 };
+          wchar_t *p;
+
+          wcscpy (working_dir, dbus_path);
+          p = wcsrchr (working_dir, L'\\');
+          if (p != NULL)
+            *p = L'\0';
+
+          wcscpy (args, L"\"");
+          wcscat (args, dbus_path);
+          wcscat (args, L"\" ");
 #define _L_PREFIX_FOR_EXPANDED(arg) L##arg
 #define _L_PREFIX(arg) _L_PREFIX_FOR_EXPANDED (arg)
-             wcscat (args, _L_PREFIX (_GDBUS_ARG_WIN32_RUN_SESSION_BUS));
+          wcscat (args, _L_PREFIX (_GDBUS_ARG_WIN32_RUN_SESSION_BUS));
 #undef _L_PREFIX
 #undef _L_PREFIX_FOR_EXPANDED
 
-             res = CreateProcessW (exe_path, args,
-                                   0, 0, FALSE,
-                                   NORMAL_PRIORITY_CLASS | CREATE_NO_WINDOW | DETACHED_PROCESS,
-                                   0, gio_path,
-                                   &si, &pi);
-           }
-         if (res)
-           {
-             address = read_shm (DBUS_DAEMON_ADDRESS_INFO);
-             if (address == NULL)
-               g_warning ("%S dbus binary failed to launch bus, maybe incompatible version", exe_path );
-           }
-       }
+          res = CreateProcessW (dbus_path, args,
+                                0, 0, FALSE,
+                                NORMAL_PRIORITY_CLASS | CREATE_NO_WINDOW | DETACHED_PROCESS,
+                                0, working_dir,
+                                &si, &pi);
+
+          if (res)
+            {
+              address = read_shm (DBUS_DAEMON_ADDRESS_INFO);
+              if (address == NULL)
+                g_warning ("%S dbus binary failed to launch bus, maybe incompatible version", dbus_path);
+            }
+
+          g_free (dbus_path);
+        }
     }
 
   release_mutex (autolaunch_mutex);