src/support/syscall.C

   1 #include <config.h>
   2
   3 #ifdef __GNUG__
   4 #pragma implementation
   5 #endif
   6
   7 #include <cerrno>
   8 #include <sys/types.h>
   9 #include <sys/wait.h>
  10 #include <csignal>
  11 #include <cstdlib>
  12 #include <unistd.h>
  13 #include "debug.h"
  14 #include "syscall.h"
  15 #include "syscontr.h"
  16 #include "support/lstrings.h"
  17 #include "support/lyxlib.h"
  18 #include "support/filetools.h"
  19 #include "support/os.h"
  20
  21 using std::endl;
  22
  23
  24 Systemcalls::Systemcalls() {
  25         pid = 0; // No child yet
  26 }
  27
  28 Systemcalls::Systemcalls(Starttype how, string const & what, Callbackfct cback)
  29 {
  30         startscript(how, what, cback);
  31 }
  32
  33 Systemcalls::~Systemcalls() {
  34 #if 0
  35         // If the child is alive, we have to brutally kill it
  36         if (getpid() != 0) {
  37                 lyx::kill(getpid(), SIGKILL);
  38         }
  39 #endif
  40 }
  41
  42 // Start a childprocess
  43 //
  44 // if child runs in background, add information to global controller.
  45
  46 int Systemcalls::startscript() {
  47         retval = 0;
  48         switch (start) {
  49         case System:
  50         case SystemDontWait:
  51                 retval = ::system(command.c_str());
  52                 callback();
  53                 break;
  54         case Wait:
  55                 pid = fork();
  56                 if (pid>0) { // Fork succesful. Wait for child
  57                         waitForChild();
  58                         callback();
  59                 } else
  60                         retval = 1;
  61                 break;
  62         case DontWait:
  63                 pid = fork();
  64                 if (pid>0) {
  65                         // Now integrate into Controller
  66                         SystemcallsSingletoncontroller::Startcontroller starter;
  67                         SystemcallsSingletoncontroller * contr = starter.getController();
  68                         // Add this to controller
  69                         contr->addCall(*this);
  70                 } else
  71                         retval = 1;
  72                 break;
  73         }
  74         return retval;
  75 }
  76
  77 void Systemcalls::kill(int /*tolerance*/) {
  78         if (getpid() == 0) {
  79                 lyxerr << "LyX: Can't kill non-existing process." << endl;
  80                 return;
  81         }
  82         int ret = lyx::kill(getpid(), SIGHUP);
  83         bool wait_for_death = true;
  84         if (ret != 0) {
  85                 if (errno == ESRCH) {
  86                         // The process is already dead!
  87                         wait_for_death = false;
  88                 } else {
  89                         // Something is rotten - maybe we lost permissions?
  90                 }
  91         }
  92         if (wait_for_death) {
  93                 // Here, we should add the PID to a list of
  94                 // waiting processes to kill if they are not
  95                 // dead within tolerance seconds
  96
  97                 // CHECK Implement this using the timer of
  98                 // the singleton systemcontroller (Asger)
  99
 100         }
 101 }
 102
 103
 104 // Wait for child process to finish. Returns returncode from child.
 105 void Systemcalls::waitForChild() {
 106         // We'll pretend that the child returns 1 on all errorconditions.
 107         retval = 1;
 108         int status;
 109         bool wait = true;
 110         while (wait) {
 111                 pid_t waitrpid = waitpid(pid, &status, WUNTRACED);
 112                 if (waitrpid == -1) {
 113                         lyxerr << "LyX: Error waiting for child:" << strerror(errno) << endl;
 114                         wait = false;
 115                 } else if (WIFEXITED(status)) {
 116                         // Child exited normally. Update return value.
 117                         retval = WEXITSTATUS(status);
 118                         wait = false;
 119                 } else if (WIFSIGNALED(status)) {
 120                         lyxerr << "LyX: Child didn't catch signal "
 121                                << WTERMSIG(status)
 122                                << "and died. Too bad." << endl;
 123                         wait = false;
 124                 } else if (WIFSTOPPED(status)) {
 125                         lyxerr << "LyX: Child (pid: " << pid
 126                                << ") stopped on signal "
 127                                << WSTOPSIG(status)
 128                                << ". Waiting for child to finish." << endl;
 129                 } else {
 130                         lyxerr << "LyX: Something rotten happened while "
 131                                 "waiting for child " << pid << endl;
 132                         wait = false;
 133                 }
 134         }
 135 }
 136
 137
 138 // generate child in background
 139
 140 pid_t Systemcalls::fork()
 141 {
 142         #ifndef __EMX__
 143         pid_t cpid= ::fork();
 144         if (cpid == 0) { // child
 145         #endif
 146                 // TODO: Consider doing all of this before the fork, otherwise me
 147                 // might have troubles with multi-threaded access. (Baruch 20010228)
 148                 string childcommand(command); // copy
 149                 string rest = split(command, childcommand, ' ');
 150                 const int MAX_ARGV = 255;
 151                 char *syscmd = 0;
 152                 char *argv[MAX_ARGV];
 153                 int  index = 0;
 154                 bool more = true;
 155                 while (more) {
 156                         childcommand = frontStrip(childcommand);
 157                         if (syscmd == 0) {
 158                                 syscmd = new char[childcommand.length() + 1];
 159                                 childcommand.copy(syscmd, childcommand.length());
 160                                 syscmd[childcommand.length()] = '\0';
 161                         }
 162                         if (!childcommand.empty()) {
 163                         char * tmp = new char[childcommand.length() + 1];
 164                         childcommand.copy(tmp, childcommand.length());
 165                         tmp[childcommand.length()] = '\0';
 166                         argv[index++] = tmp;
 167                         }
 168
 169                         // reinit
 170                         more = !rest.empty();
 171                         if (more)
 172                                 rest = split(rest, childcommand, ' ');
 173                 }
 174                 argv[index] = 0;
 175                 // replace by command. Expand using PATH-environment-var.
 176 #ifndef __EMX__
 177                 execvp(syscmd, argv);
 178                 // If something goes wrong, we end up here:
 179                 lyxerr << "LyX: execvp failed: " << strerror(errno) << endl;
 180         } else if (cpid < 0) { // error
 181 #else
 182         pid_t cpid = spawnvp(P_SESSION|P_DEFAULT|P_MINIMIZE|P_BACKGROUND, syscmd, argv);
 183         if (cpid < 0) { // error
 184 #endif
 185                 lyxerr << "LyX: Could not fork: " << strerror(errno) << endl;
 186         } else { // parent
 187                 return cpid;
 188         }
 189         return 0;
 190 }
 191
 192
 193 // Reuse of instance
 194
 195 int Systemcalls::startscript(Starttype how, string const & what,
 196                              Callbackfct cback)
 197 {
 198         start   = how;
 199         command = what;
 200         cbk     = cback;
 201         pid     = static_cast<pid_t>(0); // yet no child
 202         retval  = 0;
 203
 204         if (how == SystemDontWait) {
 205                 (os::shell() == os::UNIX) ? command += " &"
 206                                           : command = "start /min/n " + command;
 207         }
 208
 209         return startscript();
 210 }
 211
 212
 213
 214 //
 215 // Mini-Test-environment for script-classes
 216 //
 217 #ifdef TEST_MAIN
 218 #include <stdio.h>
 219
 220
 221 int SimulateTimer;
 222 void back(string cmd, int retval)
 223 {
 224         ::printf("Done: %s gave %d\n", cmd.c_str(), retval);
 225         SimulateTimer = 0;
 226 }
 227
 228
 229 int main(int, char **)
 230 {
 231
 232         SystemcallsSingletoncontroller::Startcontroller starter;
 233         SystemcallsSingletoncontroller *contr= starter.GetController();
 234
 235         Systemcalls one(Systemcalls::System, "ls -ltag", back);
 236         Systemcalls two(Systemcalls::Wait, "ls -ltag", back);
 237         SimulateTimer = 1;
 238         Systemcalls three(Systemcalls::DontWait , "ls -ltag", back);
 239         // Simulation of timer
 240         while (SimulateTimer)
 241                 {
 242                         sleep(1);
 243                         contr->Timer();
 244                 }
 245 }
 246 #endif