2 * \file ForkedCalls.cpp
3 * This file is part of LyX, the document processor.
4 * Licence details can be found in the file COPYING.
6 * \author Asger Alstrup
7 * \author Angus Leeming
8 * \author Alfredo Braunstein
10 * Full author contact details are available in file CREDITS.
15 #include "support/ForkedCalls.h"
17 #include "support/debug.h"
18 #include "support/filetools.h"
19 #include "support/lstrings.h"
20 #include "support/lyxlib.h"
21 #include "support/os.h"
22 #include "support/Timeout.h"
24 #include "support/bind.h"
44 # include <sys/wait.h>
56 /////////////////////////////////////////////////////////////////////
60 /////////////////////////////////////////////////////////////////////
62 class Murder : public boost::signals::trackable {
65 static void killItDead(int secs, pid_t pid)
68 new Murder(secs, pid);
70 support::kill(pid, SIGKILL);
77 support::kill(pid_, SIGKILL);
78 lyxerr << "Killed " << pid_ << endl;
84 Murder(int secs, pid_t pid)
85 : timeout_(1000*secs, Timeout::ONETIME), pid_(pid)
87 timeout_.timeout.connect(bind(&Murder::kill, this));
100 /////////////////////////////////////////////////////////////////////
104 /////////////////////////////////////////////////////////////////////
106 ForkedProcess::ForkedProcess()
107 : pid_(0), retval_(0)
111 bool ForkedProcess::IAmAChild = false;
114 void ForkedProcess::emitSignal()
117 signal_->operator()(pid_, retval_);
122 // Spawn the child process
123 int ForkedProcess::run(Starttype type)
126 pid_ = generateChild();
127 if (pid_ <= 0) { // child or fork failed.
130 //we also do this in fork(), too, but maybe someone will try
138 retval_ = waitForChild();
141 // Integrate into the Controller
142 ForkedCallsController::addCall(*this);
151 bool ForkedProcess::running() const
156 #if !defined (_WIN32)
157 // Un-UNIX like, but we don't have much use for
158 // knowing if a zombie exists, so just reap it first.
160 waitpid(pid(), &waitstatus, WNOHANG);
163 // Racy of course, but it will do.
164 if (support::kill(pid(), 0) && errno == ESRCH)
170 void ForkedProcess::kill(int tol)
172 lyxerr << "ForkedProcess::kill(" << tol << ')' << endl;
174 lyxerr << "Can't kill non-existent process!" << endl;
178 int const tolerance = max(0, tol);
179 if (tolerance == 0) {
181 Murder::killItDead(0, pid());
183 int ret = support::kill(pid(), SIGHUP);
185 // The process is already dead if wait_for_death is false
186 bool const wait_for_death = (ret == 0 && errno != ESRCH);
189 Murder::killItDead(tolerance, pid());
194 pid_t ForkedProcess::fork() {
195 #if !defined (HAVE_FORK)
198 pid_t pid = ::fork();
206 // Wait for child process to finish. Returns returncode from child.
207 int ForkedProcess::waitForChild()
209 // We'll pretend that the child returns 1 on all error conditions.
213 HANDLE const hProcess = HANDLE(pid_);
215 DWORD const wait_status = ::WaitForSingleObject(hProcess, INFINITE);
217 switch (wait_status) {
218 case WAIT_OBJECT_0: {
220 if (!GetExitCodeProcess(hProcess, &exit_code)) {
221 lyxerr << "GetExitCodeProcess failed waiting for child\n"
222 << getChildErrorMessage() << endl;
228 lyxerr << "WaitForSingleObject failed waiting for child\n"
229 << getChildErrorMessage() << endl;
237 pid_t waitrpid = waitpid(pid_, &status, WUNTRACED);
238 if (waitrpid == -1) {
239 lyxerr << "LyX: Error waiting for child:"
240 << strerror(errno) << endl;
242 } else if (WIFEXITED(status)) {
243 // Child exited normally. Update return value.
244 retval_ = WEXITSTATUS(status);
246 } else if (WIFSIGNALED(status)) {
247 lyxerr << "LyX: Child didn't catch signal "
249 << "and died. Too bad." << endl;
251 } else if (WIFSTOPPED(status)) {
252 lyxerr << "LyX: Child (pid: " << pid_
253 << ") stopped on signal "
255 << ". Waiting for child to finish." << endl;
257 lyxerr << "LyX: Something rotten happened while "
258 "waiting for child " << pid_ << endl;
267 /////////////////////////////////////////////////////////////////////
271 /////////////////////////////////////////////////////////////////////
274 int ForkedCall::startScript(Starttype wait, string const & what)
277 retval_ = startScript(what, SignalTypePtr());
287 int ForkedCall::startScript(string const & what, SignalTypePtr signal)
292 return run(DontWait);
296 // generate child in background
297 int ForkedCall::generateChild()
299 string line = trim(command_);
303 // Split the input command up into an array of words stored
304 // in a contiguous block of memory. The array contains pointers
306 // Don't forget the terminating `\0' character.
307 char const * const c_str = line.c_str();
308 vector<char> vec(c_str, c_str + line.size() + 1);
310 // Splitting the command up into an array of words means replacing
311 // the whitespace between words with '\0'. Life is complicated
312 // however, because words protected by quotes can contain whitespace.
314 // The strategy we adopt is:
315 // 1. If we're not inside quotes, then replace white space with '\0'.
316 // 2. If we are inside quotes, then don't replace the white space
317 // but do remove the quotes themselves. We do this naively by
318 // replacing the quote with '\0' which is fine if quotes
319 // delimit the entire word.
320 char inside_quote = 0;
321 vector<char>::iterator it = vec.begin();
322 vector<char>::iterator const end = vec.end();
323 for (; it != end; ++it) {
328 else if (c == '\'' || c == '"') {
331 // spawnvp *requires* the quotes or it will
332 // split the arg at the internal whitespace!
333 // Make shure the quote is a DOS-style one.
340 } else if (c == inside_quote) {
350 // Build an array of pointers to each word.
354 for (; it != end; ++it) {
355 if (*it != '\0' && prev == '\0')
356 argv.push_back(&*it);
362 if (lyxerr.debugging(Debug::FILES)) {
363 vector<char *>::iterator ait = argv.begin();
364 vector<char *>::iterator const aend = argv.end();
365 lyxerr << "<command>\n\t" << line
366 << "\n\tInterpretted as:\n\n";
367 for (; ait != aend; ++ait)
369 lyxerr << '\t'<< *ait << '\n';
370 lyxerr << "</command>" << endl;
374 pid_t const cpid = spawnvp(_P_NOWAIT, argv[0], &*argv.begin());
376 pid_t const cpid = ::fork();
379 execvp(argv[0], &*argv.begin());
381 // If something goes wrong, we end up here
382 lyxerr << "execvp of \"" << command_ << "\" failed: "
383 << strerror(errno) << endl;
390 lyxerr << "Could not fork: " << strerror(errno) << endl;
397 /////////////////////////////////////////////////////////////////////
401 /////////////////////////////////////////////////////////////////////
403 namespace ForkedCallQueue {
405 /// A process in the queue
406 typedef pair<string, ForkedCall::SignalTypePtr> Process;
407 /** Add a process to the queue. Processes are forked sequentially
408 * only one is running at a time.
409 * Connect to the returned signal and you'll be informed when
410 * the process has ended.
412 ForkedCall::SignalTypePtr add(string const & process);
414 /// in-progress queue
415 static queue<Process> callQueue_;
417 /// flag whether queue is running
418 static bool running_ = 0;
425 void callback(pid_t, int);
427 ForkedCall::SignalTypePtr add(string const & process)
429 ForkedCall::SignalTypePtr ptr;
430 ptr.reset(new ForkedCall::SignalType);
431 callQueue_.push(Process(process, ptr));
440 if (callQueue_.empty())
442 Process pro = callQueue_.front();
444 // Bind our chain caller
445 pro.second->connect(bind(&ForkedCallQueue::callback, _1, _2));
447 //If we fail to fork the process, then emit the signal
448 //to tell the outside world that it failed.
449 if (call.startScript(pro.first, pro.second) > 0)
450 pro.second->operator()(0,1);
454 void callback(pid_t, int)
456 if (callQueue_.empty())
465 LYXERR(Debug::GRAPHICS, "ForkedCallQueue: waking up");
474 LYXERR(Debug::GRAPHICS, "ForkedCallQueue: I'm going to sleep");
483 } // namespace ForkedCallsQueue
487 /////////////////////////////////////////////////////////////////////
489 // ForkedCallsController
491 /////////////////////////////////////////////////////////////////////
494 string const getChildErrorMessage()
496 DWORD const error_code = ::GetLastError();
498 HLOCAL t_message = 0;
499 bool const ok = ::FormatMessage(
500 FORMAT_MESSAGE_ALLOCATE_BUFFER |
501 FORMAT_MESSAGE_FROM_SYSTEM,
503 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
504 (LPTSTR) &t_message, 0, 0
508 ss << "LyX: Error waiting for child: " << error_code;
511 ss << ": " << (LPTSTR)t_message;
512 ::LocalFree(t_message);
514 ss << ": Error unknown.";
521 namespace ForkedCallsController {
523 typedef shared_ptr<ForkedProcess> ForkedProcessPtr;
524 typedef list<ForkedProcessPtr> ListType;
525 typedef ListType::iterator iterator;
528 /// The child processes
529 static ListType forkedCalls;
531 iterator find_pid(pid_t pid)
533 return find_if(forkedCalls.begin(), forkedCalls.end(),
534 bind(equal_to<pid_t>(),
535 bind(&ForkedCall::pid, _1),
540 void addCall(ForkedProcess const & newcall)
542 forkedCalls.push_back(newcall.clone());
546 // Check the list of dead children and emit any associated signals.
547 void handleCompletedProcesses()
549 ListType::iterator it = forkedCalls.begin();
550 ListType::iterator end = forkedCalls.end();
552 ForkedProcessPtr actCall = *it;
553 bool remove_it = false;
556 HANDLE const hProcess = HANDLE(actCall->pid());
558 DWORD const wait_status = ::WaitForSingleObject(hProcess, 0);
560 switch (wait_status) {
564 case WAIT_OBJECT_0: {
566 if (!GetExitCodeProcess(hProcess, &exit_code)) {
567 lyxerr << "GetExitCodeProcess failed waiting for child\n"
568 << getChildErrorMessage() << endl;
569 // Child died, so pretend it returned 1
570 actCall->setRetValue(1);
572 actCall->setRetValue(exit_code);
578 lyxerr << "WaitForSingleObject failed waiting for child\n"
579 << getChildErrorMessage() << endl;
580 actCall->setRetValue(1);
585 pid_t pid = actCall->pid();
587 pid_t const waitrpid = waitpid(pid, &stat_loc, WNOHANG);
589 if (waitrpid == -1) {
590 lyxerr << "LyX: Error waiting for child: "
591 << strerror(errno) << endl;
593 // Child died, so pretend it returned 1
594 actCall->setRetValue(1);
597 } else if (waitrpid == 0) {
598 // Still running. Move on to the next child.
600 } else if (WIFEXITED(stat_loc)) {
601 // Ok, the return value goes into retval.
602 actCall->setRetValue(WEXITSTATUS(stat_loc));
605 } else if (WIFSIGNALED(stat_loc)) {
606 // Child died, so pretend it returned 1
607 actCall->setRetValue(1);
610 } else if (WIFSTOPPED(stat_loc)) {
611 lyxerr << "LyX: Child (pid: " << pid
612 << ") stopped on signal "
613 << WSTOPSIG(stat_loc)
614 << ". Waiting for child to finish." << endl;
617 lyxerr << "LyX: Something rotten happened while "
618 "waiting for child " << pid << endl;
620 // Child died, so pretend it returned 1
621 actCall->setRetValue(1);
627 forkedCalls.erase(it);
628 actCall->emitSignal();
630 /* start all over: emiting the signal can result
631 * in changing the list (Ab)
633 it = forkedCalls.begin();
641 // Kill the process prematurely and remove it from the list
642 // within tolerance secs
643 void kill(pid_t pid, int tolerance)
645 ListType::iterator it = find_pid(pid);
646 if (it == forkedCalls.end())
649 (*it)->kill(tolerance);
650 forkedCalls.erase(it);
653 } // namespace ForkedCallsController
655 } // namespace support