updater: move the windows process starting code to comphelper

Change-Id: I1a499f57d01ee28afdb2c4f85dc976f2e6837dfd
Reviewed-on: https://gerrit.libreoffice.org/40837
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

3 files changed, 296 insertions, 0 deletions

diff --git a/comphelper/Module_comphelper.mk b/comphelper/Module_comphelper.mk
index e04d230d2069..30ac708a927d 100644
--- a/comphelper/Module_comphelper.mk
+++ b/comphelper/Module_comphelper.mk
@@ -21,6 +21,8 @@ $(eval $(call gb_Module_Module,comphelper))
 
 $(eval $(call gb_Module_add_targets,comphelper,\
     Library_comphelper \
+	$(if $(filter WNT,$(OS)),\
+		StaticLibrary_windows_process )\
 ))
 
 $(eval $(call gb_Module_add_subsequentcheck_targets,comphelper,\
diff --git a/comphelper/StaticLibrary_windows_process.mk b/comphelper/StaticLibrary_windows_process.mk
new file mode 100644
index 000000000000..1b086eac952b
--- /dev/null
+++ b/comphelper/StaticLibrary_windows_process.mk
@@ -0,0 +1,24 @@
+# -*- Mode: makefile-gmake; tab-width: 4; indent-tabs-mode: t -*-
+#
+# This file is part of the LibreOffice project.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+
+$(eval $(call gb_StaticLibrary_StaticLibrary,windows_process))
+
+$(eval $(call gb_StaticLibrary_set_include,windows_process,\
+	$$(INCLUDE) \
+))
+
+$(eval $(call gb_StaticLibrary_add_defs,windows_process,\
+	-DUNICODE \
+))
+
+$(eval $(call gb_StaticLibrary_add_exception_objects,windows_process,\
+	comphelper/source/windows/windows_process \
+))
+
+# vim:set shiftwidth=4 tabstop=4 noexpandtab: */
diff --git a/comphelper/source/windows/windows_process.cxx b/comphelper/source/windows/windows_process.cxx
new file mode 100644
index 000000000000..1c782d7a289f
--- /dev/null
+++ b/comphelper/source/windows/windows_process.cxx
@@ -0,0 +1,270 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <windows.h>
+#include <shellapi.h>
+
+#include <cstddef>
+#include <cwchar>
+
+// Needed for CreateEnvironmentBlock
+#include <userenv.h>
+#pragma comment(lib, "userenv.lib")
+
+/**
+ * Get the length that the string will take and takes into account the
+ * additional length if the string needs to be quoted and if characters need to
+ * be escaped.
+ */
+static int ArgStrLen(const wchar_t *s)
+{
+    int backslashes = 0;
+    int i = wcslen(s);
+    BOOL hasDoubleQuote = wcschr(s, L'"') != nullptr;
+    // Only add doublequotes if the string contains a space or a tab
+    BOOL addDoubleQuotes = wcspbrk(s, L" \t") != nullptr;
+
+    if (addDoubleQuotes)
+    {
+        i += 2; // initial and final duoblequote
+    }
+
+    if (hasDoubleQuote)
+    {
+        while (*s)
+        {
+            if (*s == '\\')
+            {
+                ++backslashes;
+            }
+            else
+            {
+                if (*s == '"')
+                {
+                    // Escape the doublequote and all backslashes preceding the doublequote
+                    i += backslashes + 1;
+                }
+
+                backslashes = 0;
+            }
+
+            ++s;
+        }
+    }
+
+    return i;
+}
+
+/**
+ * Copy string "s" to string "d", quoting the argument as appropriate and
+ * escaping doublequotes along with any backslashes that immediately precede
+ * doublequotes.
+ * The CRT parses this to retrieve the original argc/argv that we meant,
+ * see STDARGV.C in the MSVC CRT sources.
+ *
+ * @return the end of the string
+ */
+static wchar_t* ArgToString(wchar_t *d, const wchar_t *s)
+{
+    int backslashes = 0;
+    BOOL hasDoubleQuote = wcschr(s, L'"') != nullptr;
+    // Only add doublequotes if the string contains a space or a tab
+    BOOL addDoubleQuotes = wcspbrk(s, L" \t") != nullptr;
+
+    if (addDoubleQuotes)
+    {
+        *d = '"'; // initial doublequote
+        ++d;
+    }
+
+    if (hasDoubleQuote)
+    {
+        int i;
+        while (*s)
+        {
+            if (*s == '\\')
+            {
+                ++backslashes;
+            }
+            else
+            {
+                if (*s == '"')
+                {
+                    // Escape the doublequote and all backslashes preceding the doublequote
+                    for (i = 0; i <= backslashes; ++i)
+                    {
+                        *d = '\\';
+                        ++d;
+                    }
+                }
+
+                backslashes = 0;
+            }
+
+            *d = *s;
+            ++d;
+            ++s;
+        }
+    }
+    else
+    {
+        wcscpy(d, s);
+        d += wcslen(s);
+    }
+
+    if (addDoubleQuotes)
+    {
+        *d = '"'; // final doublequote
+        ++d;
+    }
+
+    return d;
+}
+
+/**
+ * Creates a command line from a list of arguments. The returned
+ * string is allocated with "malloc" and should be "free"d.
+ *
+ * argv is UTF8
+ */
+wchar_t*
+MakeCommandLine(int argc, wchar_t **argv)
+{
+    int i;
+    int len = 0;
+
+    // The + 1 of the last argument handles the allocation for null termination
+    for (i = 0; i < argc; ++i)
+        len += ArgStrLen(argv[i]) + 1;
+
+    // Protect against callers that pass 0 arguments
+    if (len == 0)
+        len = 1;
+
+    wchar_t *s = (wchar_t*) malloc(len * sizeof(wchar_t));
+    if (!s)
+        return nullptr;
+
+    wchar_t *c = s;
+    for (i = 0; i < argc; ++i)
+    {
+        c = ArgToString(c, argv[i]);
+        if (i + 1 != argc)
+        {
+            *c = ' ';
+            ++c;
+        }
+    }
+
+    *c = '\0';
+
+    return s;
+}
+
+/**
+ * Launch a child process with the specified arguments.
+ * @note argv[0] is ignored
+ * @note The form of this function that takes char **argv expects UTF-8
+ */
+BOOL
+WinLaunchChild(const wchar_t *exePath,
+               int argc, wchar_t **argv,
+               HANDLE userToken = nullptr,
+               HANDLE *hProcess = nullptr);
+
+BOOL
+WinLaunchChild(const wchar_t *exePath,
+               int argc,
+               wchar_t **argv,
+               HANDLE userToken,
+               HANDLE *hProcess)
+{
+    wchar_t *cl;
+    BOOL ok;
+
+    cl = MakeCommandLine(argc, argv);
+    if (!cl)
+    {
+        return FALSE;
+    }
+
+    STARTUPINFOW si = {0};
+    si.cb = sizeof(STARTUPINFOW);
+    si.lpDesktop = L"winsta0\\Default";
+    PROCESS_INFORMATION pi = {0};
+
+    if (userToken == nullptr)
+    {
+        ok = CreateProcessW(exePath,
+                            cl,
+                            nullptr,  // no special security attributes
+                            nullptr,  // no special thread attributes
+                            FALSE, // don't inherit filehandles
+                            0,     // creation flags
+                            nullptr,  // inherit my environment
+                            nullptr,  // use my current directory
+                            &si,
+                            &pi);
+    }
+    else
+    {
+        // Create an environment block for the process we're about to start using
+        // the user's token.
+        LPVOID environmentBlock = nullptr;
+        if (!CreateEnvironmentBlock(&environmentBlock, userToken, TRUE))
+        {
+            environmentBlock = nullptr;
+        }
+
+        ok = CreateProcessAsUserW(userToken,
+                                  exePath,
+                                  cl,
+                                  nullptr,  // no special security attributes
+                                  nullptr,  // no special thread attributes
+                                  FALSE,    // don't inherit filehandles
+                                  0,        // creation flags
+                                  environmentBlock,
+                                  nullptr,  // use my current directory
+                                  &si,
+                                  &pi);
+
+        if (environmentBlock)
+        {
+            DestroyEnvironmentBlock(environmentBlock);
+        }
+    }
+
+    if (ok)
+    {
+        if (hProcess)
+        {
+            *hProcess = pi.hProcess; // the caller now owns the HANDLE
+        }
+        else
+        {
+            CloseHandle(pi.hProcess);
+        }
+        CloseHandle(pi.hThread);
+    }
+    else
+    {
+        LPVOID lpMsgBuf = nullptr;
+        FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                      FORMAT_MESSAGE_FROM_SYSTEM |
+                      FORMAT_MESSAGE_IGNORE_INSERTS,
+                      nullptr,
+                      GetLastError(),
+                      MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                      (LPTSTR) &lpMsgBuf,
+                      0,
+                      nullptr);
+        wprintf(L"Error restarting: %s\n", lpMsgBuf ? lpMsgBuf : L"(null)");
+        if (lpMsgBuf)
+            LocalFree(lpMsgBuf);
+    }
+
+    free(cl);
+
+    return ok;
+}