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https://git.lyx.org/repos/lyx.git
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1741c87a4e
The main change is to support/ForkedCalls.{h,cpp}. We introduce a static variable IAmAChild and a corresponding accessor. This is set to true in a new fork() method, in the branch taken by the child. (Note: fork() is safe cross-platform, as it just returns -1 if we don't have fork().) This ForkedProcess::iAmAChild() method is then used to protect GuiView::message(). As Abdel has pointed out, there may be other such calls to be protected, e.g., the emission of the Buffer::changed() signal. Those are not addressed here. git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@22587 a592a061-630c-0410-9148-cb99ea01b6c8
657 lines
14 KiB
C++
657 lines
14 KiB
C++
/**
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* \file ForkedCalls.cpp
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* This file is part of LyX, the document processor.
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* Licence details can be found in the file COPYING.
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*
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* \author Asger Alstrup
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* \author Angus Leeming
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* \author Alfredo Braunstein
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*
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* Full author contact details are available in file CREDITS.
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*/
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#include <config.h>
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#include "support/ForkedCalls.h"
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#include "support/debug.h"
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#include "support/filetools.h"
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#include "support/lstrings.h"
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#include "support/lyxlib.h"
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#include "support/os.h"
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#include "support/Timeout.h"
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#include <boost/bind.hpp>
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#include <cerrno>
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#include <queue>
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#include <sstream>
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#include <utility>
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#include <vector>
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#ifdef _WIN32
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# define SIGHUP 1
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# define SIGKILL 9
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# include <windows.h>
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# include <process.h>
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# undef max
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#else
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# include <csignal>
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# include <cstdlib>
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# ifdef HAVE_UNISTD_H
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# include <unistd.h>
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# endif
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# include <sys/wait.h>
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#endif
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using namespace std;
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using boost::bind;
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namespace lyx {
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namespace support {
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namespace {
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/////////////////////////////////////////////////////////////////////
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//
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// Murder
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//
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/////////////////////////////////////////////////////////////////////
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class Murder : public boost::signals::trackable {
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public:
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//
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static void killItDead(int secs, pid_t pid)
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{
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if (secs > 0)
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new Murder(secs, pid);
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else if (pid != 0)
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support::kill(pid, SIGKILL);
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}
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//
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void kill()
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{
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if (pid_ != 0)
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support::kill(pid_, SIGKILL);
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lyxerr << "Killed " << pid_ << endl;
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delete this;
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}
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private:
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//
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Murder(int secs, pid_t pid)
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: timeout_(1000*secs, Timeout::ONETIME), pid_(pid)
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{
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timeout_.timeout.connect(boost::bind(&Murder::kill, this));
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timeout_.start();
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}
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//
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Timeout timeout_;
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//
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pid_t pid_;
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};
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} // namespace anon
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/////////////////////////////////////////////////////////////////////
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//
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// ForkedProcess
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//
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/////////////////////////////////////////////////////////////////////
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ForkedProcess::ForkedProcess()
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: pid_(0), retval_(0)
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{}
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bool ForkedProcess::IAmAChild = false;
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void ForkedProcess::emitSignal()
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{
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if (signal_.get()) {
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signal_->operator()(pid_, retval_);
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}
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}
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// Spawn the child process
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int ForkedProcess::run(Starttype type)
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{
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retval_ = 0;
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pid_ = generateChild();
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if (pid_ <= 0) { // child or fork failed.
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retval_ = 1;
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if (pid_ == 0)
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//we also do this in fork(), too, but maybe someone will try
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//to bypass that
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IAmAChild = true;
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return retval_;
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}
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switch (type) {
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case Wait:
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retval_ = waitForChild();
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break;
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case DontWait: {
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// Integrate into the Controller
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ForkedCallsController::addCall(*this);
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break;
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}
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}
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return retval_;
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}
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bool ForkedProcess::running() const
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{
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if (!pid())
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return false;
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#if !defined (_WIN32)
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// Un-UNIX like, but we don't have much use for
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// knowing if a zombie exists, so just reap it first.
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int waitstatus;
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waitpid(pid(), &waitstatus, WNOHANG);
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#endif
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// Racy of course, but it will do.
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if (support::kill(pid(), 0) && errno == ESRCH)
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return false;
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return true;
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}
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void ForkedProcess::kill(int tol)
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{
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lyxerr << "ForkedProcess::kill(" << tol << ')' << endl;
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if (pid() == 0) {
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lyxerr << "Can't kill non-existent process!" << endl;
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return;
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}
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int const tolerance = max(0, tol);
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if (tolerance == 0) {
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// Kill it dead NOW!
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Murder::killItDead(0, pid());
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} else {
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int ret = support::kill(pid(), SIGHUP);
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// The process is already dead if wait_for_death is false
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bool const wait_for_death = (ret == 0 && errno != ESRCH);
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if (wait_for_death)
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Murder::killItDead(tolerance, pid());
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}
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}
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pid_t ForkedProcess::fork() {
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#if !defined (HAVE_FORK)
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return -1;
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#else
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pid_t pid = ::fork();
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if (pid == 0)
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IAmAChild = true;
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return pid;
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#endif
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}
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// Wait for child process to finish. Returns returncode from child.
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int ForkedProcess::waitForChild()
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{
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// We'll pretend that the child returns 1 on all error conditions.
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retval_ = 1;
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#if defined (_WIN32)
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HANDLE const hProcess = HANDLE(pid_);
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DWORD const wait_status = ::WaitForSingleObject(hProcess, INFINITE);
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switch (wait_status) {
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case WAIT_OBJECT_0: {
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DWORD exit_code = 0;
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if (!GetExitCodeProcess(hProcess, &exit_code)) {
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lyxerr << "GetExitCodeProcess failed waiting for child\n"
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<< getChildErrorMessage() << endl;
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} else
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retval_ = exit_code;
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break;
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}
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case WAIT_FAILED:
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lyxerr << "WaitForSingleObject failed waiting for child\n"
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<< getChildErrorMessage() << endl;
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break;
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}
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#else
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int status;
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bool wait = true;
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while (wait) {
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pid_t waitrpid = waitpid(pid_, &status, WUNTRACED);
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if (waitrpid == -1) {
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lyxerr << "LyX: Error waiting for child:"
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<< strerror(errno) << endl;
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wait = false;
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} else if (WIFEXITED(status)) {
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// Child exited normally. Update return value.
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retval_ = WEXITSTATUS(status);
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wait = false;
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} else if (WIFSIGNALED(status)) {
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lyxerr << "LyX: Child didn't catch signal "
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<< WTERMSIG(status)
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<< "and died. Too bad." << endl;
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wait = false;
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} else if (WIFSTOPPED(status)) {
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lyxerr << "LyX: Child (pid: " << pid_
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<< ") stopped on signal "
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<< WSTOPSIG(status)
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<< ". Waiting for child to finish." << endl;
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} else {
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lyxerr << "LyX: Something rotten happened while "
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"waiting for child " << pid_ << endl;
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wait = false;
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}
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}
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#endif
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return retval_;
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}
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/////////////////////////////////////////////////////////////////////
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//
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// ForkedCall
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//
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/////////////////////////////////////////////////////////////////////
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int ForkedCall::startScript(Starttype wait, string const & what)
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{
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if (wait != Wait) {
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retval_ = startScript(what, SignalTypePtr());
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return retval_;
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}
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command_ = what;
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signal_.reset();
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return run(Wait);
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}
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int ForkedCall::startScript(string const & what, SignalTypePtr signal)
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{
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command_ = what;
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signal_ = signal;
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return run(DontWait);
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}
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// generate child in background
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int ForkedCall::generateChild()
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{
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string line = trim(command_);
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if (line.empty())
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return 1;
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// Split the input command up into an array of words stored
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// in a contiguous block of memory. The array contains pointers
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// to each word.
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// Don't forget the terminating `\0' character.
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char const * const c_str = line.c_str();
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vector<char> vec(c_str, c_str + line.size() + 1);
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// Splitting the command up into an array of words means replacing
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// the whitespace between words with '\0'. Life is complicated
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// however, because words protected by quotes can contain whitespace.
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//
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// The strategy we adopt is:
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// 1. If we're not inside quotes, then replace white space with '\0'.
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// 2. If we are inside quotes, then don't replace the white space
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// but do remove the quotes themselves. We do this naively by
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// replacing the quote with '\0' which is fine if quotes
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// delimit the entire word.
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char inside_quote = 0;
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vector<char>::iterator it = vec.begin();
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vector<char>::iterator const end = vec.end();
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for (; it != end; ++it) {
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char const c = *it;
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if (!inside_quote) {
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if (c == ' ')
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*it = '\0';
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else if (c == '\'' || c == '"') {
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#if defined (_WIN32)
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// How perverse!
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// spawnvp *requires* the quotes or it will
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// split the arg at the internal whitespace!
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// Make shure the quote is a DOS-style one.
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*it = '"';
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#else
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*it = '\0';
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#endif
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inside_quote = c;
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}
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} else if (c == inside_quote) {
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#if defined (_WIN32)
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*it = '"';
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#else
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*it = '\0';
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#endif
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inside_quote = 0;
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}
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}
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// Build an array of pointers to each word.
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it = vec.begin();
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vector<char *> argv;
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char prev = '\0';
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for (; it != end; ++it) {
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if (*it != '\0' && prev == '\0')
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argv.push_back(&*it);
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prev = *it;
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}
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argv.push_back(0);
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// Debug output.
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if (lyxerr.debugging(Debug::FILES)) {
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vector<char *>::iterator ait = argv.begin();
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vector<char *>::iterator const aend = argv.end();
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lyxerr << "<command>\n\t" << line
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<< "\n\tInterpretted as:\n\n";
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for (; ait != aend; ++ait)
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if (*ait)
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lyxerr << '\t'<< *ait << '\n';
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lyxerr << "</command>" << endl;
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}
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#ifdef _WIN32
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pid_t const cpid = spawnvp(_P_NOWAIT, argv[0], &*argv.begin());
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#else // POSIX
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pid_t const cpid = ::fork();
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if (cpid == 0) {
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// Child
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execvp(argv[0], &*argv.begin());
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// If something goes wrong, we end up here
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lyxerr << "execvp of \"" << command_ << "\" failed: "
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<< strerror(errno) << endl;
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_exit(1);
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}
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#endif
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if (cpid < 0) {
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// Error.
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lyxerr << "Could not fork: " << strerror(errno) << endl;
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}
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return cpid;
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}
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/////////////////////////////////////////////////////////////////////
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//
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// ForkedCallQueue
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//
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/////////////////////////////////////////////////////////////////////
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namespace ForkedCallQueue {
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/// A process in the queue
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typedef pair<string, ForkedCall::SignalTypePtr> Process;
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/** Add a process to the queue. Processes are forked sequentially
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* only one is running at a time.
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* Connect to the returned signal and you'll be informed when
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* the process has ended.
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*/
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ForkedCall::SignalTypePtr add(string const & process);
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/// in-progress queue
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static queue<Process> callQueue_;
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/// flag whether queue is running
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static bool running_ = 0;
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///
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void startCaller();
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///
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void stopCaller();
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///
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void callback(pid_t, int);
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ForkedCall::SignalTypePtr add(string const & process)
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{
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ForkedCall::SignalTypePtr ptr;
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ptr.reset(new ForkedCall::SignalType);
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callQueue_.push(Process(process, ptr));
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if (!running_)
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startCaller();
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return ptr;
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}
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void callNext()
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{
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if (callQueue_.empty())
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return;
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Process pro = callQueue_.front();
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callQueue_.pop();
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// Bind our chain caller
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pro.second->connect(boost::bind(&ForkedCallQueue::callback, _1, _2));
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ForkedCall call;
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//<2F>If<49>we<77>fail<69>to<74>fork<72>the<68>process,<2C>then<65>emit<69>the<68>signal
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//<2F>to<74>tell<6C>the<68>outside<64>world<6C>that<61>it<69>failed.
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if (call.startScript(pro.first, pro.second) > 0)
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pro.second->operator()(0,1);
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}
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void callback(pid_t, int)
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{
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if (callQueue_.empty())
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stopCaller();
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else
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callNext();
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}
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void startCaller()
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{
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LYXERR(Debug::GRAPHICS, "ForkedCallQueue: waking up");
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running_ = true ;
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callNext();
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}
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void stopCaller()
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{
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running_ = false ;
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LYXERR(Debug::GRAPHICS, "ForkedCallQueue: I'm going to sleep");
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}
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bool running()
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{
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return running_;
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}
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} // namespace ForkedCallsQueue
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/////////////////////////////////////////////////////////////////////
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//
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// ForkedCallsController
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//
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/////////////////////////////////////////////////////////////////////
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#if defined(_WIN32)
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string const getChildErrorMessage()
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{
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DWORD const error_code = ::GetLastError();
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HLOCAL t_message = 0;
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bool const ok = ::FormatMessage(
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FORMAT_MESSAGE_ALLOCATE_BUFFER |
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FORMAT_MESSAGE_FROM_SYSTEM,
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0, error_code,
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MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
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(LPTSTR) &t_message, 0, 0
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) != 0;
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ostringstream ss;
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ss << "LyX: Error waiting for child: " << error_code;
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if (ok) {
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ss << ": " << (LPTSTR)t_message;
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::LocalFree(t_message);
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} else
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ss << ": Error unknown.";
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return ss.str();
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}
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#endif
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namespace ForkedCallsController {
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typedef boost::shared_ptr<ForkedProcess> ForkedProcessPtr;
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typedef list<ForkedProcessPtr> ListType;
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typedef ListType::iterator iterator;
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/// The child processes
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static ListType forkedCalls;
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iterator find_pid(pid_t pid)
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{
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return find_if(forkedCalls.begin(), forkedCalls.end(),
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bind(equal_to<pid_t>(),
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bind(&ForkedCall::pid, _1),
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pid));
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}
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void addCall(ForkedProcess const & newcall)
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{
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forkedCalls.push_back(newcall.clone());
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}
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// Check the list of dead children and emit any associated signals.
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void handleCompletedProcesses()
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{
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ListType::iterator it = forkedCalls.begin();
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ListType::iterator end = forkedCalls.end();
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while (it != end) {
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ForkedProcessPtr actCall = *it;
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bool remove_it = false;
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#if defined(_WIN32)
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HANDLE const hProcess = HANDLE(actCall->pid());
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DWORD const wait_status = ::WaitForSingleObject(hProcess, 0);
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switch (wait_status) {
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case WAIT_TIMEOUT:
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// Still running
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break;
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case WAIT_OBJECT_0: {
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DWORD exit_code = 0;
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if (!GetExitCodeProcess(hProcess, &exit_code)) {
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lyxerr << "GetExitCodeProcess failed waiting for child\n"
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<< getChildErrorMessage() << endl;
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// Child died, so pretend it returned 1
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actCall->setRetValue(1);
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} else {
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actCall->setRetValue(exit_code);
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}
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remove_it = true;
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break;
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}
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case WAIT_FAILED:
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lyxerr << "WaitForSingleObject failed waiting for child\n"
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<< getChildErrorMessage() << endl;
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actCall->setRetValue(1);
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remove_it = true;
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break;
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}
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#else
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pid_t pid = actCall->pid();
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||
int stat_loc;
|
||
pid_t const waitrpid = waitpid(pid, &stat_loc, WNOHANG);
|
||
|
||
if (waitrpid == -1) {
|
||
lyxerr << "LyX: Error waiting for child: "
|
||
<< strerror(errno) << endl;
|
||
|
||
// Child died, so pretend it returned 1
|
||
actCall->setRetValue(1);
|
||
remove_it = true;
|
||
|
||
} else if (waitrpid == 0) {
|
||
// Still running. Move on to the next child.
|
||
|
||
} else if (WIFEXITED(stat_loc)) {
|
||
// Ok, the return value goes into retval.
|
||
actCall->setRetValue(WEXITSTATUS(stat_loc));
|
||
remove_it = true;
|
||
|
||
} else if (WIFSIGNALED(stat_loc)) {
|
||
// Child died, so pretend it returned 1
|
||
actCall->setRetValue(1);
|
||
remove_it = true;
|
||
|
||
} else if (WIFSTOPPED(stat_loc)) {
|
||
lyxerr << "LyX: Child (pid: " << pid
|
||
<< ") stopped on signal "
|
||
<< WSTOPSIG(stat_loc)
|
||
<< ". Waiting for child to finish." << endl;
|
||
|
||
} else {
|
||
lyxerr << "LyX: Something rotten happened while "
|
||
"waiting for child " << pid << endl;
|
||
|
||
// Child died, so pretend it returned 1
|
||
actCall->setRetValue(1);
|
||
remove_it = true;
|
||
}
|
||
#endif
|
||
|
||
if (remove_it) {
|
||
forkedCalls.erase(it);
|
||
actCall->emitSignal();
|
||
|
||
/* start all over: emiting the signal can result
|
||
* in changing the list (Ab)
|
||
*/
|
||
it = forkedCalls.begin();
|
||
} else {
|
||
++it;
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
// Kill the process prematurely and remove it from the list
|
||
// within tolerance secs
|
||
void kill(pid_t pid, int tolerance)
|
||
{
|
||
ListType::iterator it = find_pid(pid);
|
||
if (it == forkedCalls.end())
|
||
return;
|
||
|
||
(*it)->kill(tolerance);
|
||
forkedCalls.erase(it);
|
||
}
|
||
|
||
} // namespace ForkedCallsController
|
||
|
||
} // namespace support
|
||
} // namespace lyx
|