57 lines
2.5 KiB
C++
57 lines
2.5 KiB
C++
#include <TestCommon.h>
|
|
|
|
const int SC_CONSOLE_MARK = 0xFFF2;
|
|
const int SC_CONSOLE_SELECT_ALL = 0xFFF5;
|
|
|
|
int main() {
|
|
SpawnParams sp;
|
|
sp.bInheritHandles = TRUE;
|
|
|
|
trace("----------------------------------");
|
|
Worker p;
|
|
p.getStdout().write("<-- origBuffer -->");
|
|
|
|
auto c = p.child();
|
|
auto cb = c.newBuffer();
|
|
cb.activate();
|
|
cb.write("<-- cb -->");
|
|
|
|
// This is what the winpty-agent would want to do:
|
|
// - It tries to "freeze" the console with "Select All", which blocks
|
|
// WriteConsole but little else. Closing a screen buffer is not
|
|
// blocked.
|
|
// - Then, winpty wants to get the buffer info, then read screen content.
|
|
// - If the child process closes its special screen buffer during the
|
|
// scraping, then on Windows 7, conhost can start reading freed memory
|
|
// and crash. In this test case, `info2` is frequently garbage.
|
|
// Somehow winpty-agent needs to avoid this situation, but options seem
|
|
// scarce:
|
|
// - The Windows 7 bug only happens with `CloseHandle` AFAICT. If a
|
|
// buffer handle goes away implicitly from `FreeConsole` or process
|
|
// exit, then the buffer is reference counted properly. If app
|
|
// developers avoid closing their buffer handle, winpty can work.
|
|
// - Be really careful about when to scrape. Pay close attention to
|
|
// the kinds of WinEvents a full-screen app generates just before it
|
|
// exits, and try to fast-path everything such that no scraping is
|
|
// necessary.
|
|
// - Start interfering with the user processes attached to the console.
|
|
// - e.g. inject a DLL inside the processes and open CONOUT$, or
|
|
// override APIs, etc.
|
|
// - Attach to the right console process before opening CONOUT$. If
|
|
// that console's buffer handle is inheritable, then opening CONOUT$
|
|
// will then produce a safe handle.
|
|
// - Accept a certain amount of unreliability.
|
|
SendMessage(p.consoleWindow(), WM_SYSCOMMAND, SC_CONSOLE_SELECT_ALL, 0);
|
|
auto scrape = p.openConout();
|
|
auto info1 = scrape.screenBufferInfo();
|
|
cb.close();
|
|
Sleep(200); // Helps the test fail more often.
|
|
auto info2 = scrape.screenBufferInfo();
|
|
SendMessage(p.consoleWindow(), WM_CHAR, 27, 0x00010001);
|
|
|
|
trace("%d %d %d %d", info1.srWindow.Left, info1.srWindow.Top, info1.srWindow.Right, info1.srWindow.Bottom);
|
|
trace("%d %d %d %d", info2.srWindow.Left, info2.srWindow.Top, info2.srWindow.Right, info2.srWindow.Bottom);
|
|
|
|
Sleep(300000);
|
|
}
|