123 lines
4.4 KiB
C++
123 lines
4.4 KiB
C++
//
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// 2015-09-25
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// I measured these limits on the size of a single ReadConsoleOutputW call.
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// The limit seems to more-or-less disppear with Windows 8, which is the first
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// OS to stop using ALPCs for console I/O. My guess is that the new I/O
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// method does not use the 64KiB shared memory buffer that the ALPC method
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// uses.
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//
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// I'm guessing the remaining difference between Windows 8/8.1 and Windows 10
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// might be related to the 32-vs-64-bitness.
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//
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// Client OSs
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//
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// Windows XP 32-bit VM ==> up to 13304 characters
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// - 13304x1 works, but 13305x1 fails instantly
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// Windows 7 32-bit VM ==> between 16-17 thousand characters
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// - 16000x1 works, 17000x1 fails instantly
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// - 163x100 *crashes* conhost.exe but leaves VeryLargeRead.exe running
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// Windows 8 32-bit VM ==> between 240-250 million characters
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// - 10000x24000 works, but 10000x25000 does not
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// Windows 8.1 32-bit VM ==> between 240-250 million characters
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// - 10000x24000 works, but 10000x25000 does not
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// Windows 10 64-bit VM ==> no limit (tested to 576 million characters)
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// - 24000x24000 works
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// - `ver` reports [Version 10.0.10240], conhost.exe and ConhostV1.dll are
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// 10.0.10240.16384 for file and product version. ConhostV2.dll is
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// 10.0.10240.16391 for file and product version.
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//
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// Server OSs
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//
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// Windows Server 2008 64-bit VM ==> 14300-14400 characters
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// - 14300x1 works, 14400x1 fails instantly
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// - This OS does not have conhost.exe.
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// - `ver` reports [Version 6.0.6002]
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// Windows Server 2008 R2 64-bit VM ==> 15600-15700 characters
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// - 15600x1 works, 15700x1 fails instantly
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// - This OS has conhost.exe, and procexp.exe reveals console ALPC ports in
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// use in conhost.exe.
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// - `ver` reports [Version 6.1.7601], conhost.exe is 6.1.7601.23153 for file
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// and product version.
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// Windows Server 2012 64-bit VM ==> at least 100 million characters
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// - 10000x10000 works (VM had only 1GiB of RAM, so I skipped larger tests)
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// - This OS has Windows 8's task manager and procexp.exe reveals the same
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// lack of ALPC ports and the same \Device\ConDrv\* files as Windows 8.
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// - `ver` reports [Version 6.2.9200], conhost.exe is 6.2.9200.16579 for file
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// and product version.
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//
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// To summarize:
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//
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// client-OS server-OS notes
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// ---------------------------------------------------------------------------
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// XP Server 2008 CSRSS, small reads
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// 7 Server 2008 R2 ALPC-to-conhost, small reads
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// 8, 8.1 Server 2012 new I/O interface, large reads allowed
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// 10 <no server OS yet> enhanced console w/rewrapping
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//
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// (Presumably, Win2K, Vista, and Win2K3 behave the same as XP. conhost.exe
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// was announced as a Win7 feature.)
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//
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#include <windows.h>
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#include <assert.h>
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#include <vector>
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#include "TestUtil.cc"
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int main(int argc, char *argv[]) {
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long long width = 9000;
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long long height = 9000;
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assert(argc >= 1);
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if (argc == 4) {
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width = atoi(argv[2]);
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height = atoi(argv[3]);
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} else {
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if (argc == 3) {
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width = atoi(argv[1]);
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height = atoi(argv[2]);
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}
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wchar_t args[1024];
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swprintf(args, 1024, L"CHILD %lld %lld", width, height);
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startChildProcess(args);
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return 0;
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}
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const HANDLE conout = GetStdHandle(STD_OUTPUT_HANDLE);
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setWindowPos(0, 0, 1, 1);
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setBufferSize(width, height);
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setWindowPos(0, 0, std::min(80LL, width), std::min(50LL, height));
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setCursorPos(0, 0);
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printf("A");
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fflush(stdout);
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setCursorPos(width - 2, height - 1);
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printf("B");
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fflush(stdout);
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trace("sizeof(CHAR_INFO) = %d", (int)sizeof(CHAR_INFO));
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trace("Allocating buffer...");
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CHAR_INFO *buffer = new CHAR_INFO[width * height];
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assert(buffer != NULL);
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memset(&buffer[0], 0, sizeof(CHAR_INFO));
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memset(&buffer[width * height - 2], 0, sizeof(CHAR_INFO));
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COORD bufSize = { width, height };
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COORD bufCoord = { 0, 0 };
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SMALL_RECT readRegion = { 0, 0, width - 1, height - 1 };
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trace("ReadConsoleOutputW: calling...");
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BOOL success = ReadConsoleOutputW(conout, buffer, bufSize, bufCoord, &readRegion);
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trace("ReadConsoleOutputW: success=%d", success);
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assert(buffer[0].Char.UnicodeChar == L'A');
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assert(buffer[width * height - 2].Char.UnicodeChar == L'B');
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trace("Top-left and bottom-right characters read successfully!");
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Sleep(30000);
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delete [] buffer;
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return 0;
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}
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