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