src/support/forkedcontr.C

   1 /**
   2  * \file forkedcontr.C
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author Asger Alstrup Nielsen
   7  * \author Angus Leeming
   8  *
   9  * Full author contact details are available in file CREDITS
  10  *
  11  * A class for the control of child processes launched using
  12  * fork() and execvp().
  13  */
  14
  15 #include <config.h>
  16
  17 #include "forkedcontr.h"
  18 #include "forkedcall.h"
  19 #include "lyxfunctional.h"
  20 #include "debug.h"
  21
  22 #include "frontends/Timeout.h"
  23
  24 #include <boost/bind.hpp>
  25
  26 #include <cerrno>
  27 #include <cstdlib>
  28 #include <unistd.h>
  29 #include <sys/wait.h>
  30
  31 using std::vector;
  32 using std::endl;
  33 using std::find_if;
  34
  35 #ifndef CXX_GLOBAL_CSTD
  36 using std::strerror;
  37 #endif
  38
  39 // Ensure, that only one controller exists inside process
  40 ForkedcallsController & ForkedcallsController::get()
  41 {
  42         static ForkedcallsController singleton;
  43         return singleton;
  44 }
  45
  46
  47 ForkedcallsController::ForkedcallsController()
  48 {
  49         timeout_ = new Timeout(100, Timeout::ONETIME);
  50
  51         timeout_->timeout
  52                 .connect(boost::bind(&ForkedcallsController::timer, this));
  53 }
  54
  55
  56 // open question: should we stop childs here?
  57 // Asger says no: I like to have my xdvi open after closing LyX. Maybe
  58 // I want to print or something.
  59 ForkedcallsController::~ForkedcallsController()
  60 {
  61         for (ListType::iterator it = forkedCalls.begin();
  62              it != forkedCalls.end(); ++it) {
  63                 delete *it;
  64         }
  65
  66         delete timeout_;
  67 }
  68
  69
  70 void ForkedcallsController::addCall(ForkedProcess const & newcall)
  71 {
  72         if (!timeout_->running())
  73                 timeout_->start();
  74
  75         forkedCalls.push_back(newcall.clone());
  76         childrenChanged();
  77 }
  78
  79
  80 // Timer-call
  81 // Check the list and, if there is a stopped child, emit the signal.
  82 void ForkedcallsController::timer()
  83 {
  84         ListType::size_type start_size = forkedCalls.size();
  85
  86         ListType::iterator it  = forkedCalls.begin();
  87         ListType::iterator end = forkedCalls.end();
  88         while (it != end) {
  89                 ForkedProcess * actCall = *it;
  90
  91                 pid_t pid = actCall->pid();
  92                 int stat_loc;
  93                 pid_t const waitrpid = waitpid(pid, &stat_loc, WNOHANG);
  94                 bool remove_it = false;
  95
  96                 if (waitrpid == -1) {
  97                         lyxerr << "LyX: Error waiting for child: "
  98                                << strerror(errno) << endl;
  99
 100                         // Child died, so pretend it returned 1
 101                         actCall->setRetValue(1);
 102                         remove_it = true;
 103
 104                 } else if (waitrpid == 0) {
 105                         // Still running. Move on to the next child.
 106                         continue;
 107
 108                 } else if (WIFEXITED(stat_loc)) {
 109                         // Ok, the return value goes into retval.
 110                         actCall->setRetValue(WEXITSTATUS(stat_loc));
 111                         remove_it = true;
 112
 113                 } else if (WIFSIGNALED(stat_loc)) {
 114                         // Child died, so pretend it returned 1
 115                         actCall->setRetValue(1);
 116                         remove_it = true;
 117
 118                 } else if (WIFSTOPPED(stat_loc)) {
 119                         lyxerr << "LyX: Child (pid: " << pid
 120                                << ") stopped on signal "
 121                                << WSTOPSIG(stat_loc)
 122                                << ". Waiting for child to finish." << endl;
 123
 124                 } else {
 125                         lyxerr << "LyX: Something rotten happened while "
 126                                 "waiting for child " << pid << endl;
 127
 128                         // Child died, so pretend it returned 1
 129                         actCall->setRetValue(1);
 130                         remove_it = true;
 131                 }
 132
 133                 if (remove_it) {
 134                         forkedCalls.erase(it);
 135
 136                         actCall->emitSignal();
 137                         delete actCall;
 138
 139                         /* start all over: emiting the signal can result
 140                          * in changing the list (Ab)
 141                          */
 142                         it = forkedCalls.begin();
 143                 } else {
 144                         ++it;
 145                 }
 146         }
 147
 148         if (!forkedCalls.empty() && !timeout_->running()) {
 149                 timeout_->start();
 150         }
 151
 152         if (start_size != forkedCalls.size())
 153                 childrenChanged();
 154 }
 155
 156
 157 // Return a vector of the pids of all the controlled processes.
 158 vector<pid_t> const ForkedcallsController::getPIDs() const
 159 {
 160         vector<pid_t> pids;
 161
 162         if (forkedCalls.empty())
 163                 return pids;
 164
 165         pids.resize(forkedCalls.size());
 166
 167         vector<pid_t>::iterator vit = pids.begin();
 168         for (ListType::const_iterator lit = forkedCalls.begin();
 169              lit != forkedCalls.end(); ++lit, ++vit) {
 170                 *vit = (*lit)->pid();
 171         }
 172
 173         std::sort(pids.begin(), pids.end());
 174         return pids;
 175 }
 176
 177
 178 // Get the command string of the process.
 179 string const ForkedcallsController::getCommand(pid_t pid) const
 180 {
 181         ListType::const_iterator it =
 182                 find_if(forkedCalls.begin(), forkedCalls.end(),
 183                         lyx::compare_memfun(&Forkedcall::pid, pid));
 184
 185         if (it == forkedCalls.end())
 186                 return string();
 187
 188         return (*it)->command();
 189 }
 190
 191
 192 // Kill the process prematurely and remove it from the list
 193 // within tolerance secs
 194 void ForkedcallsController::kill(pid_t pid, int tolerance)
 195 {
 196         ListType::iterator it =
 197                 find_if(forkedCalls.begin(), forkedCalls.end(),
 198                         lyx::compare_memfun(&Forkedcall::pid, pid));
 199
 200         if (it == forkedCalls.end())
 201                 return;
 202
 203         (*it)->kill(tolerance);
 204         forkedCalls.erase(it);
 205
 206         if (forkedCalls.empty()) {
 207                 timeout_->stop();
 208         }
 209 }