src/support/syscall.C

   1 #include <config.h>
   2
   3 #ifdef __GNUG__
   4 #pragma implementation
   5 #endif
   6
   7 #include <errno.h>
   8 #include <sys/types.h>
   9 #include <sys/wait.h>
  10 #include <signal.h>
  11 #include <cstdlib>
  12 #include <cstdio>
  13 #include <unistd.h>
  14 #include "debug.h"
  15 #include "syscall.h"
  16 #include "syscontr.h"
  17 #include "support/lstrings.h"
  18
  19 Systemcalls::Systemcalls() {
  20         pid = (pid_t) 0; // No child yet
  21 }
  22
  23 Systemcalls::Systemcalls(Starttype how, string const & what, Callbackfct cback)
  24 {
  25         start   = how;
  26         command = what;
  27         cbk     = cback;
  28         pid     = (pid_t) 0;
  29         retval  = 0;
  30         startscript();
  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                 ::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                 retval = system(command.c_str());
  51                 callback();
  52                 break;
  53         case Wait:
  54                 pid = fork();
  55                 if (pid>0) { // Fork succesful. Wait for child
  56                         waitForChild();
  57                         callback();
  58                 } else
  59                         retval = 1;
  60                 break;
  61         case DontWait:
  62                 pid = fork();
  63                 if (pid>0) {
  64                         // Now integrate into Controller
  65                         SystemcallsSingletoncontroller::Startcontroller starter;
  66                         SystemcallsSingletoncontroller * contr = starter.getController();
  67                         // Add this to controller
  68                         contr->addCall(*this);
  69                 } else
  70                         retval = 1;
  71                 break;
  72         }
  73         return retval;
  74 }
  75
  76 void Systemcalls::kill(int tolerance) {
  77         if (getpid() == 0) {
  78                 lyxerr << "LyX: Can't kill non-existing process." << endl;
  79                 return;
  80         }
  81         int ret = ::kill(getpid(), SIGHUP);
  82         bool wait_for_death = true;
  83         if (ret != 0) {
  84                 if (errno == ESRCH) {
  85                         // The process is already dead!
  86                         wait_for_death = false;
  87                 } else {
  88                         // Something is rotten - maybe we lost permissions?
  89                 }
  90         }
  91         if (wait_for_death) {
  92                 // Here, we should add the PID to a list of
  93                 // waiting processes to kill if they are not
  94                 // dead without tolerance seconds
  95 #warning Implement this using the timer of the singleton systemcontroller (Asger)
  96         }
  97 }
  98
  99
 100 // Wait for child process to finish. Returns returncode from child.
 101 void Systemcalls::waitForChild() {
 102         // We'll pretend that the child returns 1 on all errorconditions.
 103         retval = 1;
 104         int status;
 105         bool wait = true;
 106         while (wait) {
 107                 pid_t waitrpid = waitpid(pid, &status, WUNTRACED);
 108                 if (waitrpid == -1) {
 109                         lyxerr << "LyX: Error waiting for child:" << strerror(errno) << endl;
 110                         wait = false;
 111                 } else if (WIFEXITED(status)) {
 112                         // Child exited normally. Update return value.
 113                         retval = WEXITSTATUS(status);
 114                         wait = false;
 115                 } else if (WIFSIGNALED(status)) {
 116                         lyxerr << "LyX: Child didn't catch signal "
 117                                << WTERMSIG(status)
 118                                << "and died. Too bad." << endl;
 119                         wait = false;
 120                 } else if (WIFSTOPPED(status)) {
 121                         lyxerr << "LyX: Child (pid: " << pid
 122                                << ") stopped on signal "
 123                                << WSTOPSIG(status)
 124                                << ". Waiting for child to finish." << endl;
 125                 } else {
 126                         lyxerr << "LyX: Something rotten happened while "
 127                                 "waiting for child " << pid << endl;
 128                         wait = false;
 129                 }
 130         }
 131 }
 132
 133
 134 // generate child in background
 135
 136 pid_t Systemcalls::fork()
 137 {
 138         pid_t cpid= ::fork();
 139         if (cpid == 0) { // child
 140                 string childcommand(command); // copy
 141                 string rest = split(command, childcommand, ' ');
 142                 const int MAX_ARGV = 255;
 143                 char *syscmd = 0;
 144                 char *argv[MAX_ARGV];
 145                 int  index = 0;
 146                 bool more;
 147                 do {
 148                         if (syscmd == 0) {
 149                                 syscmd = new char[childcommand.length() + 1];
 150                                 childcommand.copy(syscmd, childcommand.length());
 151                                 syscmd[childcommand.length()] = '\0';
 152                         }
 153                         char * tmp = new char[childcommand.length() + 1];
 154                         childcommand.copy(tmp, childcommand.length());
 155                         tmp[childcommand.length()] = '\0';
 156                         argv[index++] = tmp;
 157                         // reinit
 158                         more = !rest.empty();
 159                         if (more)
 160                                 rest = split(rest, childcommand, ' ');
 161                 } while (more);
 162                 argv[index] = 0;
 163                 // replace by command. Expand using PATH-environment-var.
 164                 execvp(syscmd, argv);
 165                 // If something goes wrong, we end up here:
 166                 lyxerr << "LyX: execvp failed: " << strerror(errno) << endl;
 167         } else if (cpid < 0) { // error
 168                 lyxerr << "LyX: Could not fork: " << strerror(errno) << endl;
 169         } else { // parent
 170                 return cpid;
 171         }
 172         return 0;
 173 }
 174
 175
 176 // Reuse of instance
 177
 178 int Systemcalls::startscript(Starttype how, string const & what,
 179                              Callbackfct cback)
 180 {
 181         start   = how;
 182         command = what;
 183         cbk     = cback;
 184         pid     = (pid_t) 0; // yet no child
 185         retval  = 0;
 186         return startscript();
 187 }
 188
 189
 190
 191 //
 192 // Mini-Test-environment for script-classes
 193 //
 194 #ifdef TEST_MAIN
 195 #include <stdio.h>
 196
 197
 198 int SimulateTimer;
 199 void back(string cmd, int retval)
 200 {
 201         printf("Done: %s gave %d\n", cmd.c_str(), retval);
 202         SimulateTimer = 0;
 203 }
 204
 205
 206 int main(int, char**)
 207 {
 208
 209         SystemcallsSingletoncontroller::Startcontroller starter;
 210         SystemcallsSingletoncontroller *contr=starter.GetController();
 211
 212         Systemcalls one(Systemcalls::System, "ls -ltag", back);
 213         Systemcalls two(Systemcalls::Wait, "ls -ltag", back);
 214         SimulateTimer = 1;
 215         Systemcalls three(Systemcalls::DontWait , "ls -ltag", back);
 216         // Simulation of timer
 217         while (SimulateTimer)
 218                 {
 219                         sleep(1);
 220                         contr->Timer();
 221                 }
 222 }
 223 #endif