Initial commit

.gitignore

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+dist/
+*.exe
+*.obj

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2014 Fylwind
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Makefile

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+DIST=dist^\
+TMP=$(DIST)tmp^\
+CFLAGS=/nologo /Fe$(DIST) /Fo$(TMP) /GL /Ox /W4
+
+main: $(DIST)widexe.exe
+
+$(DIST)widexe.exe: widexe.c
+	-md $(DIST) $(TMP)
+	$(CC) $(CFLAGS) widexe.c
+
+clean:
+	-rd /s /q dist

README.md

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+Windows Executable Identifier
+=============================
+
+Simple tool that identifies the subsystem of a Windows executable, i.e. is it
+a console program, a GUI program, or something else?
+
+This is based on the sample code in article
+[KB90493](http://support.microsoft.com/kb/90493) (*HOWTO: How To Determine
+Whether an Application is Console or GUI*).
+
+To compile, run `nmake` in the Visual Studio Command Prompt.

widexe.c

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+#include <stdio.h>
+#include <stdlib.h>
+#ifndef UNICODE
+#  define UNICODE
+#endif
+#include <windows.h>
+#if defined(__MINGW32__) && !defined(IMAGE_SUBSYSTEM_WINDOWS_BOOT_APPLICATION)
+#  define IMAGE_SUBSYSTEM_WINDOWS_BOOT_APPLICATION 16
+#endif
+#define XFER_BUFFER_SIZE 2048
+#ifndef IMAGE_SIZEOF_NT_OPTIONAL_HEADER
+#  define IMAGE_SIZEOF_NT_OPTIONAL32_HEADER 224
+#  define IMAGE_SIZEOF_NT_OPTIONAL64_HEADER 240
+#  ifdef _WIN64
+#    define IMAGE_SIZEOF_NT_OPTIONAL_HEADER IMAGE_SIZEOF_NT_OPTIONAL64_HEADER
+#  else
+#    define IMAGE_SIZEOF_NT_OPTIONAL_HEADER IMAGE_SIZEOF_NT_OPTIONAL32_HEADER
+#  endif
+#endif
+
+int abs_seek(HANDLE hFile, LONG offset, DWORD* newOffset) {
+    *newOffset = SetFilePointer(hFile, offset, NULL, FILE_BEGIN);
+    if (*newOffset == INVALID_SET_FILE_POINTER) {
+        fwprintf(stderr, L"SetFilePointer failed, error %lu.\n",
+                 GetLastError());
+        return 0;
+    }
+    return 1;
+}
+
+int read_bytes(HANDLE hFile, LPVOID buffer, DWORD size) {
+    DWORD bytes;
+    if (!ReadFile(hFile, buffer, size, &bytes, NULL)) {
+        fwprintf(stderr, L"ReadFile failed, error %lu.\n", GetLastError());
+        return 0;
+    } else if (size != bytes) {
+        fwprintf(stderr,
+                 L"Read the wrong number of bytes, expected %lu, got %lu.\n",
+                 size, bytes);
+        return 0;
+    }
+    return 1;
+}
+
+int wmain(int argc, wchar_t** argv) {
+    HANDLE handle;
+    DWORD coff_header_offset;
+    DWORD more_dos_header[16];
+    ULONG nt_signature;
+    IMAGE_DOS_HEADER image_dos_header;
+    IMAGE_FILE_HEADER image_file_header;
+    IMAGE_OPTIONAL_HEADER image_optional_header;
+
+    if (argc != 2) {
+        fwprintf(stderr,
+                 L"Usage: %s FILE\n"
+                 L"Identifies the subsystem of a Windows executable.\n",
+                 argv[0]);
+        return EXIT_FAILURE;
+    }
+
+    /* Open the reference file. */
+    handle = CreateFile(argv[1], GENERIC_READ, FILE_SHARE_READ, NULL,
+                        OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+
+    if (handle == INVALID_HANDLE_VALUE) {
+        DWORD error = GetLastError();
+        if (error == ERROR_FILE_NOT_FOUND)
+            fwprintf(stderr, L"Can't find: %s\n", argv[1]);
+        else
+            fwprintf(stderr, L"Error %lu: can't open: %s\n", error, argv[1]);
+        return EXIT_FAILURE;
+    }
+
+    /*  Read the MS-DOS image header. */
+    if (!read_bytes(handle, &image_dos_header, sizeof(IMAGE_DOS_HEADER)))
+        return EXIT_FAILURE;
+
+    if (image_dos_header.e_magic != IMAGE_DOS_SIGNATURE) {
+        fwprintf(stderr, L"This doesn't seem to be an executable.\n");
+        return EXIT_FAILURE;
+    }
+
+    /* Read more MS-DOS header. */
+    if (!read_bytes(handle, more_dos_header, sizeof(more_dos_header)))
+        return EXIT_FAILURE;
+
+    /* Get actual COFF header. */
+    if (!abs_seek(handle, image_dos_header.e_lfanew, &coff_header_offset))
+        return EXIT_FAILURE;
+
+    if (!read_bytes(handle, &nt_signature, sizeof(ULONG)))
+        return EXIT_FAILURE;
+
+    if (nt_signature != IMAGE_NT_SIGNATURE) {
+        fwprintf(stderr, L"Missing NT signature.  Unknown file type.\n");
+        return EXIT_FAILURE;
+    }
+
+    if (!read_bytes(handle,&image_file_header, IMAGE_SIZEOF_FILE_HEADER))
+        return EXIT_FAILURE;
+
+    /* Read optional header. */
+    if (!read_bytes(handle, &image_optional_header,
+                    IMAGE_SIZEOF_NT_OPTIONAL_HEADER))
+        return EXIT_FAILURE;
+
+    switch (image_optional_header.Subsystem) {
+    case IMAGE_SUBSYSTEM_UNKNOWN:
+        wprintf(L"Unknown subsystem (IMAGE_SUBSYSTEM_UNKNOWN).\n");
+        break;
+    case IMAGE_SUBSYSTEM_NATIVE:
+        wprintf(L"No subsystem required (device drivers and native system "
+                L"processes).\n");
+        break;
+    case IMAGE_SUBSYSTEM_WINDOWS_GUI:
+        wprintf(L"Windows graphical user interface (GUI) subsystem.\n");
+        break;
+    case IMAGE_SUBSYSTEM_WINDOWS_CUI:
+        wprintf(L"Windows character-mode user interface (CUI) subsystem.\n");
+        break;
+    case IMAGE_SUBSYSTEM_OS2_CUI:
+        wprintf(L"OS/2 character-mode user interface (CUI) subsystem.\n");
+        break;
+    case IMAGE_SUBSYSTEM_POSIX_CUI:
+        wprintf(L"POSIX character-mode user interface (CUI) subsystem.\n");
+        break;
+    case IMAGE_SUBSYSTEM_WINDOWS_CE_GUI:
+        wprintf(L"Windows CE system.\n");
+        break;
+    case IMAGE_SUBSYSTEM_EFI_APPLICATION:
+        wprintf(L"Extensible Firmware Interface (EFI) application.\n");
+        break;
+    case IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER:
+        wprintf(L"Extensible Firmware Interface (EFI) driver with boot "
+                L"services.\n");
+        break;
+    case IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER:
+        wprintf(L"Extensible Firmware Interface (EFI) driver with run-time "
+                L"services.\n");
+        break;
+    case IMAGE_SUBSYSTEM_EFI_ROM:
+        wprintf(L"Extensible Firmware Interface (EFI) ROM image.\n");
+        break;
+    case IMAGE_SUBSYSTEM_XBOX:
+        wprintf(L"Xbox system.\n");
+        break;
+    case IMAGE_SUBSYSTEM_WINDOWS_BOOT_APPLICATION:
+        wprintf(L"Boot application.\n");
+        break;
+    default:
+        wprintf(L"Unrecognized subsystem: %u\n",
+                image_optional_header.Subsystem);
+        break;
+    }
+    return EXIT_SUCCESS;
+}
+
+/* Cygwin/MinGW doesn't support `wmain` so we have to improvise here */
+#if defined(__MINGW32__) || defined(__CYGWIN__)
+int main(int argc, char** argv) {
+    (void) argv;
+    wchar_t** argvw = CommandLineToArgvW(GetCommandLine(), &argc);
+    if (!argv) {
+        fwprintf(stderr, L"Error %lu: failed to get command-line arguments.",
+                 GetLastError());
+        return EXIT_FAILURE;
+    }
+    return wmain(argc, argvw);
+}
+#endif