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
  19 using std::endl;
  20
  21
  22 Systemcalls::Systemcalls() {
  23         pid = 0; // No child yet
  24 }
  25
  26 Systemcalls::Systemcalls(Starttype how, string const & what, Callbackfct cback)
  27 {
  28         start   = how;
  29         command = what;
  30         cbk     = cback;
  31         pid     = static_cast<pid_t>(0);
  32         retval  = 0;
  33         startscript();
  34 }
  35
  36 Systemcalls::~Systemcalls() {
  37 #if 0
  38         // If the child is alive, we have to brutally kill it
  39         if (getpid() != 0) {
  40                 lyx::kill(getpid(), SIGKILL);
  41         }
  42 #endif
  43 }
  44
  45 // Start a childprocess
  46 //
  47 // if child runs in background, add information to global controller.
  48
  49 int Systemcalls::startscript() {
  50         retval = 0;
  51         switch (start) {
  52         case System:
  53                 retval = system(command.c_str());
  54                 callback();
  55                 break;
  56         case Wait:
  57                 pid = fork();
  58                 if (pid>0) { // Fork succesful. Wait for child
  59                         waitForChild();
  60                         callback();
  61                 } else
  62                         retval = 1;
  63                 break;
  64         case DontWait:
  65                 pid = fork();
  66                 if (pid>0) {
  67                         // Now integrate into Controller
  68                         SystemcallsSingletoncontroller::Startcontroller starter;
  69                         SystemcallsSingletoncontroller * contr = starter.getController();
  70                         // Add this to controller
  71                         contr->addCall(*this);
  72                 } else
  73                         retval = 1;
  74                 break;
  75         }
  76         return retval;
  77 }
  78
  79 void Systemcalls::kill(int /*tolerance*/) {
  80         if (getpid() == 0) {
  81                 lyxerr << "LyX: Can't kill non-existing process." << endl;
  82                 return;
  83         }
  84         int ret = lyx::kill(getpid(), SIGHUP);
  85         bool wait_for_death = true;
  86         if (ret != 0) {
  87                 if (errno == ESRCH) {
  88                         // The process is already dead!
  89                         wait_for_death = false;
  90                 } else {
  91                         // Something is rotten - maybe we lost permissions?
  92                 }
  93         }
  94         if (wait_for_death) {
  95                 // Here, we should add the PID to a list of
  96                 // waiting processes to kill if they are not
  97                 // dead without tolerance seconds
  98
  99                 // CHECK Implement this using the timer of
 100                 // the singleton systemcontroller (Asger)
 101
 102         }
 103 }
 104
 105
 106 // Wait for child process to finish. Returns returncode from child.
 107 void Systemcalls::waitForChild() {
 108         // We'll pretend that the child returns 1 on all errorconditions.
 109         retval = 1;
 110         int status;
 111         bool wait = true;
 112         while (wait) {
 113                 pid_t waitrpid = waitpid(pid, &status, WUNTRACED);
 114                 if (waitrpid == -1) {
 115                         lyxerr << "LyX: Error waiting for child:" << strerror(errno) << endl;
 116                         wait = false;
 117                 } else if (WIFEXITED(status)) {
 118                         // Child exited normally. Update return value.
 119                         retval = WEXITSTATUS(status);
 120                         wait = false;
 121                 } else if (WIFSIGNALED(status)) {
 122                         lyxerr << "LyX: Child didn't catch signal "
 123                                << WTERMSIG(status)
 124                                << "and died. Too bad." << endl;
 125                         wait = false;
 126                 } else if (WIFSTOPPED(status)) {
 127                         lyxerr << "LyX: Child (pid: " << pid
 128                                << ") stopped on signal "
 129                                << WSTOPSIG(status)
 130                                << ". Waiting for child to finish." << endl;
 131                 } else {
 132                         lyxerr << "LyX: Something rotten happened while "
 133                                 "waiting for child " << pid << endl;
 134                         wait = false;
 135                 }
 136         }
 137 }
 138
 139
 140 // generate child in background
 141
 142 pid_t Systemcalls::fork()
 143 {
 144         pid_t cpid= ::fork();
 145         if (cpid == 0) { // child
 146                 string childcommand(command); // copy
 147                 string rest = split(command, childcommand, ' ');
 148                 const int MAX_ARGV = 255;
 149                 char *syscmd = 0;
 150                 char *argv[MAX_ARGV];
 151                 int  index = 0;
 152                 bool more;
 153                 do {
 154                         childcommand = frontStrip(childcommand);
 155                         if (syscmd == 0) {
 156                                 syscmd = new char[childcommand.length() + 1];
 157                                 childcommand.copy(syscmd, childcommand.length());
 158                                 syscmd[childcommand.length()] = '\0';
 159                         }
 160                         if (!childcommand.empty()) {
 161                         char * tmp = new char[childcommand.length() + 1];
 162                         childcommand.copy(tmp, childcommand.length());
 163                         tmp[childcommand.length()] = '\0';
 164                         argv[index++] = tmp;
 165                         }
 166
 167                         // reinit
 168                         more = !rest.empty();
 169                         if (more)
 170                                 rest = split(rest, childcommand, ' ');
 171                 } while (more);
 172                 argv[index] = 0;
 173                 // replace by command. Expand using PATH-environment-var.
 174                 execvp(syscmd, argv);
 175                 // If something goes wrong, we end up here:
 176                 lyxerr << "LyX: execvp failed: " << strerror(errno) << endl;
 177         } else if (cpid < 0) { // error
 178                 lyxerr << "LyX: Could not fork: " << strerror(errno) << endl;
 179         } else { // parent
 180                 return cpid;
 181         }
 182         return 0;
 183 }
 184
 185
 186 // Reuse of instance
 187
 188 int Systemcalls::startscript(Starttype how, string const & what,
 189                              Callbackfct cback)
 190 {
 191         start   = how;
 192         command = what;
 193         cbk     = cback;
 194         pid     = static_cast<pid_t>(0); // yet no child
 195         retval  = 0;
 196         return startscript();
 197 }
 198
 199
 200
 201 //
 202 // Mini-Test-environment for script-classes
 203 //
 204 #ifdef TEST_MAIN
 205 #include <stdio.h>
 206
 207
 208 int SimulateTimer;
 209 void back(string cmd, int retval)
 210 {
 211         printf("Done: %s gave %d\n", cmd.c_str(), retval);
 212         SimulateTimer = 0;
 213 }
 214
 215
 216 int main(int, char **)
 217 {
 218
 219         SystemcallsSingletoncontroller::Startcontroller starter;
 220         SystemcallsSingletoncontroller *contr= starter.GetController();
 221
 222         Systemcalls one(Systemcalls::System, "ls -ltag", back);
 223         Systemcalls two(Systemcalls::Wait, "ls -ltag", back);
 224         SimulateTimer = 1;
 225         Systemcalls three(Systemcalls::DontWait , "ls -ltag", back);
 226         // Simulation of timer
 227         while (SimulateTimer)
 228                 {
 229                         sleep(1);
 230                         contr->Timer();
 231                 }
 232 }
 233 #endif