[Installer] Graceful close and a way out of a stuck update (#7687)

* [Installer] Stop calling the payload free while an executable is locked

The guard answered "nothing is holding the payload" from two lookups that can
both miss a running instance: Restart Manager does not reliably report a
program's own image or the modules it mapped, and the image path of a process
running under another account cannot be read from the probe at all. A user log
showed exactly that: the first guard passed while cockatrice.exe was running
from the directory, the old uninstaller silently skipped the file it could not
delete, and the update aborted half an uninstall later with "cancelled by user"
after a close attempt the running window ignored.

Ask the file itself. A running image is opened without write sharing, so the
write open replacing it needs is refused with ERROR_SHARING_VIOLATION for as
long as the program runs, while a file that is merely being read still accepts
it. When neither lookup named anybody and a payload executable refuses that
open, the probe answers that the file is in use and that the program holding it
could not be identified - the guard's "could not confirm" dialog, whose Retry
works once the user has closed it - instead of passing the payload as free.

Only the payload executables are tested, not every file the purge removes: a
locked executable proves a program is running and a mapped DLL belongs to a
running executable, while a locked DLL or qt.conf can be the asking process
itself, which is the loop the guard already had. The open is retried once after
300 ms, and only for the files that refused, so a scanner holding a file for a
moment cannot stop an install for nothing.

The Windows probe check now covers that answer: a payload executable held by
the asking process, so that it cannot be named, has to come back as in use
rather than as free.

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

* [Installer] Close running clients over a local socket

The installer could only ask a running client to close with WM_CLOSE, which an instance hidden in the notification area or sitting on its own confirmation cannot answer usefully. Give every client a per-process local socket and have the holder probe ask it there first, falling back to WM_CLOSE for clients from before the socket.

* [Installer] Offer to check again or update by hand when files stay locked

Replace the two-answer guard prompt with force close, close by hand and check again, or cancel. Retry the automatic close while the set of holders changes, and point a cancelled run at the latest release so a user who does not want anything killed has a way forward that is not cancelling the update again.

---------

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

tools/installer-holder-probe/close_holders.h

@@ -17,7 +17,7 @@
  */
 struct CloseHoldersResult
 {
-    unsigned int askedToClose = 0;  ///< holders a WM_CLOSE was posted to
+    unsigned int askedToClose = 0;  ///< holders asked to close, over the socket or with WM_CLOSE
     unsigned int withoutWindow = 0; ///< holders with no window of their own to ask
     std::wstring report;            ///< one line, narrowed to ASCII when written
 };
@@ -42,16 +42,19 @@ bool isCockatriceImage(const std::wstring &imageName);
  * asked to close. Oracle and Servatrice are left to the user - Oracle writes the card
  * database in place - and so is every service.
  *
- * One thing happens per instance: its own window is asked to close with WM_CLOSE, the same
- * request as clicking that window's close button - whether it is on screen or only in the
- * notification area, since the request does not need the window to be visible and the
- * confirmation Cockatrice answers it with is a window Qt shows itself, painted, unlike one
- * restored from outside. A window that is on screen is brought forward first, because that
- * confirmation would otherwise open behind the installer's prompt; nothing is shown from
- * here. Qt's own bookkeeping windows are never the target - posting a close to the
- * notification-area one terminates the instance without its confirmation - so a process
- * without a window of its own is named and left to the guard, which offers to end it.
- * Stopping the process is never attempted here.
+ * One thing happens per instance: it is asked to close over the local socket it listens on,
+ * which is the same request as clicking its close button and is the only way to reach one
+ * whose window is hidden in the notification area or is sitting on its own confirmation. A
+ * client from before that socket is asked with WM_CLOSE on its own window instead, whether
+ * the window is on screen or only in the notification area, since the request does not need
+ * the window to be visible and the confirmation Cockatrice answers it with is a window Qt
+ * shows itself, painted, unlike one restored from outside. A window that is on screen is
+ * brought forward first, because that confirmation would otherwise open behind the
+ * installer's prompt; nothing is shown from here. Qt's own bookkeeping windows are never the
+ * target - posting a close to the notification-area one terminates the instance without its
+ * confirmation - so a process without a window of its own that does not answer the socket is
+ * named and left to the guard, which offers to end it. Stopping the process is never
+ * attempted here.
  *
  * Once the requests are out, this waits up to @c waitMilliseconds for the processes to
  * exit, so the caller can measure the purge immediately afterwards instead of sleeping