Line data    Source code

       1             : /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
       2             :    Copyright (c) 2019 The plumed team
       3             :    (see the PEOPLE file at the root of the distribution for a list of names)
       4             : 
       5             :    See http://www.plumed.org for more information.
       6             : 
       7             :    This file is part of plumed, version 2.
       8             : 
       9             :    plumed is free software: you can redistribute it and/or modify
      10             :    it under the terms of the GNU Lesser General Public License as published by
      11             :    the Free Software Foundation, either version 3 of the License, or
      12             :    (at your option) any later version.
      13             : 
      14             :    plumed is distributed in the hope that it will be useful,
      15             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      16             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      17             :    GNU Lesser General Public License for more details.
      18             : 
      19             :    You should have received a copy of the GNU Lesser General Public License
      20             :    along with plumed.  If not, see <http://www.gnu.org/licenses/>.
      21             : +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
      22             : #include "Subprocess.h"
      23             : #include "Exception.h"
      24             : #include "Tools.h"
      25             : #ifdef __PLUMED_HAS_SUBPROCESS
      26             : #include <unistd.h>
      27             : #include <csignal>
      28             : #endif
      29             : 
      30             : using namespace std;
      31             : namespace PLMD {
      32             : 
      33             : /// Small utility class, used to avoid inclusion of unistd.h> in a header file.
      34             : class SubprocessPid {
      35          17 :   static bool signals() noexcept {
      36          17 :     static const bool res=std::getenv("PLUMED_ENABLE_SIGNALS");
      37          17 :     return res;
      38             :   }
      39             : #ifdef __PLUMED_HAS_SUBPROCESS
      40             : public:
      41             :   pid_t pid;
      42           1 :   explicit SubprocessPid(pid_t pid):
      43           1 :     pid(pid)
      44             :   {
      45           1 :     plumed_assert(pid!=0 && pid!=-1);
      46           1 :   }
      47           9 :   void stop() noexcept {
      48             :     // signals give problems with MPI on Travis.
      49             :     // I disable them for now.
      50           9 :     if(signals()) if(pid!=0 && pid!=-1) kill(pid,SIGSTOP);
      51           9 :   }
      52           8 :   void cont() noexcept {
      53             :     // signals give problems with MPI on Travis.
      54             :     // I disable them for now.
      55           8 :     if(signals()) if(pid!=0 && pid!=-1) kill(pid,SIGCONT);
      56           8 :   }
      57             :   ~SubprocessPid() {
      58             :     // this is apparently working also with MPI on Travis.
      59           1 :     if(pid!=0 && pid!=-1) kill(pid,SIGINT);
      60             :   }
      61             : #endif
      62             : };
      63             : 
      64           1 : Subprocess::Subprocess(const std::string & cmd) {
      65             : #ifdef __PLUMED_HAS_SUBPROCESS
      66             :   char* arr [] = {
      67             :     // const_cast are necessary here due to the declaration of execv
      68             :     const_cast<char*>("/bin/sh"),
      69             :     const_cast<char*>("-c"),
      70             :     const_cast<char*>(cmd.c_str()),
      71             :     nullptr
      72           2 :   };
      73             :   int cp[2];
      74             :   int pc[2];
      75           1 :   if(pipe(pc)<0) plumed_error()<<"error creating parent to child pipe";
      76           1 :   if(pipe(cp)<0) plumed_error()<<"error creating child to parent pipe";
      77           1 :   pid_t pid=fork();
      78           1 :   switch(pid) {
      79             :   case -1:
      80           0 :     plumed_error()<<"error forking";
      81             :     break;
      82             : // CHILD:
      83             :   case 0:
      84             :   {
      85           0 :     if(close(1)<0) plumed_error()<<"error closing file";
      86           0 :     if(dup(cp[1])<0) plumed_error()<<"error duplicating file";
      87           0 :     if(close(0)<0) plumed_error()<<"error closing file";
      88           0 :     if(dup(pc[0])<0) plumed_error()<<"error duplicating file";
      89           0 :     if(close(pc[1])<0) plumed_error()<<"error closing file";
      90           0 :     if(close(cp[0])<0) plumed_error()<<"error closing file";
      91           0 :     execv(arr[0],arr);
      92           0 :     plumed_error()<<"error in script file";
      93             :   }
      94             : // PARENT::
      95             :   default:
      96           1 :     this->pid.reset(new SubprocessPid(pid));
      97           1 :     if(close(pc[0])<0) plumed_error()<<"error closing file";
      98           1 :     if(close(cp[1])<0) plumed_error()<<"error closing file";
      99           1 :     fpc=pc[1];
     100           1 :     fcp=cp[0];
     101           1 :     fppc=fdopen(fpc,"w");
     102           1 :     parent_to_child.link(fppc);
     103           1 :     fpcp=fdopen(fcp,"r");
     104           1 :     child_to_parent.link(fpcp);
     105             :   }
     106             : #else
     107             :   plumed_error()<<"Subprocess not supported";
     108             : #endif
     109           1 : }
     110             : 
     111           2 : Subprocess::~Subprocess() {
     112             : #ifdef __PLUMED_HAS_SUBPROCESS
     113             : // fpc should be closed to terminate the child executable
     114           1 :   fclose(fppc);
     115           1 :   close(fpc);
     116             : // fcp should not be closed because it could make the child executable fail
     117             : /// TODO: check if this is necessary and make this class exception safe!
     118             : #endif
     119           1 : }
     120             : 
     121          73 : bool Subprocess::available() noexcept {
     122             : #ifdef __PLUMED_HAS_SUBPROCESS
     123          73 :   return true;
     124             : #else
     125             :   return false;
     126             : #endif
     127             : }
     128             : 
     129           9 : void Subprocess::stop() noexcept {
     130             : #ifdef __PLUMED_HAS_SUBPROCESS
     131           9 :   pid->stop();
     132             : #endif
     133           9 : }
     134             : 
     135           8 : void Subprocess::cont() noexcept {
     136             : #ifdef __PLUMED_HAS_SUBPROCESS
     137           8 :   pid->cont();
     138             : #endif
     139           8 : }
     140             : 
     141           8 : void Subprocess::flush() {
     142           8 :   parent_to_child.flush();
     143           8 : }
     144             : 
     145           8 : Subprocess & Subprocess::getline(std::string & line) {
     146           8 :   child_to_parent.getline(line);
     147           8 :   if(!child_to_parent) plumed_error() <<"error reading subprocess";
     148           8 :   return (*this);
     149             : }
     150             : 
     151           8 : Subprocess::Handler::Handler(Subprocess *sp) noexcept:
     152           8 :   sp(sp)
     153             : {
     154           8 :   sp->cont();
     155           8 : }
     156             : 
     157           8 : Subprocess::Handler::~Handler() {
     158           8 :   if(sp) sp->stop();
     159           8 : }
     160             : 
     161           0 : Subprocess::Handler::Handler(Handler && handler) noexcept :
     162           0 :   sp(handler.sp)
     163             : {
     164           0 :   handler.sp=nullptr;
     165           0 : }
     166             : 
     167           0 : Subprocess::Handler & Subprocess::Handler::operator=(Handler && handler) noexcept {
     168           0 :   if(this!=&handler) {
     169           0 :     if(sp) sp->stop();
     170           0 :     sp=handler.sp;
     171           0 :     handler.sp=nullptr;
     172             :   }
     173           0 :   return *this;
     174             : }
     175             : 
     176             : 
     177             : }