extern "C" pid_t fork()
{
/* Acquire the wrapperExeution lock to prevent checkpoint to happen while
* processing this system call.
*/
WRAPPER_EXECUTION_GET_EXCL_LOCK();
dmtcp::KernelDeviceToConnection::instance().prepareForFork();
/* Little bit cheating here: child_time should be same for both parent and
* child, thus we compute it before forking the child. */
child_time = time(NULL);
long host = dmtcp::UniquePid::ThisProcess().hostid();
dmtcp::UniquePid parent = dmtcp::UniquePid::ThisProcess();
dmtcp::string child_name = jalib::Filesystem::GetProgramName() + "_(forked)";
//Unset this environment variable so that we can get a new virtualPid from
//the coordinator.
_dmtcp_unsetenv(ENV_VAR_VIRTUAL_PID);
coordinatorAPI.createNewConnectionBeforeFork(child_name);
pid_t virtualPid = coordinatorAPI.virtualPid();
dmtcp::Util::setVirtualPidEnvVar(virtualPid, getpid());
//Enable the pthread_atfork child call
pthread_atfork_enabled = true;
pid_t childPid = _real_fork();
if (childPid == -1) {
} else if (childPid == 0) { /* child process */
/* NOTE: Any work that needs to be done for the newly created child
* should be put into pthread_atfork_child() function. That function is
* hooked to the libc:fork() and will be called right after the new
* process is created and before the fork() returns.
*
* pthread_atfork_child is registered by calling pthread_atfork() from
* within the DmtcpWorker constructor to make sure that this is the first
* registered handle.
*/
dmtcp::UniquePid child = dmtcp::UniquePid(host, getpid(), child_time);
JTRACE("fork() done [CHILD]") (child) (parent);
} else if (childPid > 0) { /* Parent Process */
dmtcp::UniquePid child = dmtcp::UniquePid(host, childPid, child_time);
dmtcp::ProcessInfo::instance().insertChild(childPid, child);
JTRACE("fork()ed [PARENT] done") (child);;
}
pthread_atfork_enabled = false;
if (childPid != 0) {
dmtcp::Util::setVirtualPidEnvVar(getpid(), getppid());
coordinatorAPI.closeConnection();
WRAPPER_EXECUTION_RELEASE_EXCL_LOCK();
}
return childPid;
}
static void restoreSockets(dmtcp::DmtcpCoordinatorAPI& coordinatorAPI,
dmtcp::ConnectionState& ckptCoord)
{
JTRACE("restoreSockets begin");
jalib::JSocket& restoreSocket = coordinatorAPI.openRestoreSocket();
//reconnect to our coordinator
coordinatorAPI.connectToCoordinator();
coordinatorAPI.sendCoordinatorHandshake(jalib::Filesystem::GetProgramName(),
compGroup, numPeers,
DMT_RESTART_PROCESS);
coordinatorAPI.recvCoordinatorHandshake(&coordTstamp);
JTRACE("Connected to coordinator") (coordTstamp);
jalib::JSocket& coordinatorSocket = coordinatorAPI.coordinatorSocket();
// finish sockets restoration
ckptCoord.doReconnect(coordinatorSocket, restoreSocket);
JTRACE ("sockets restored!");
}
LIB_PRIVATE void pthread_atfork_child()
{
if (!pthread_atfork_enabled) {
return;
}
pthread_atfork_enabled = false;
long host = dmtcp::UniquePid::ThisProcess().hostid();
dmtcp::UniquePid parent = dmtcp::UniquePid::ThisProcess();
dmtcp::UniquePid child = dmtcp::UniquePid(host, getpid(), child_time);
dmtcp::string child_name = jalib::Filesystem::GetProgramName() + "_(forked)";
JALIB_RESET_ON_FORK();
_dmtcp_remutex_on_fork();
dmtcp::SyslogCheckpointer::resetOnFork();
dmtcp::ThreadSync::resetLocks();
dmtcp::UniquePid::resetOnFork(child);
dmtcp::Util::initializeLogFile(child_name);
dmtcp::ProcessInfo::instance().resetOnFork();
JTRACE("fork()ed [CHILD]") (child) (parent);
dmtcp::DmtcpWorker::resetOnFork(coordinatorAPI.coordinatorSocket());
}