// Author: Vadim Zeitlin
// Id: $Id$
// Copyright: (c) 1998 Robert Roebling, Vadim Zeitlin
+// (c) 2013 Rob Bresalier, Vadim Zeitlin
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#include "wx/apptrait.h"
#include "wx/process.h"
+#include "wx/scopedptr.h"
#include "wx/thread.h"
#include "wx/cmdline.h"
#include "wx/unix/execute.h"
#include "wx/unix/private.h"
-#ifdef wxHAS_GENERIC_PROCESS_CALLBACK
-#include "wx/private/fdiodispatcher.h"
-#endif
+#include "wx/evtloop.h"
+#include "wx/mstream.h"
+#include "wx/private/fdioeventloopsourcehandler.h"
#include <pwd.h>
#include <sys/wait.h> // waitpid()
#include "wx/private/pipestream.h"
#include "wx/private/streamtempinput.h"
+#include "wx/unix/private/executeiohandler.h"
#endif // HAS_PIPE_STREAMS
#endif // wxUSE_UNICODE
+namespace
+{
+
+// Helper function of wxExecute(): wait for the process termination without
+// dispatching any events.
+//
+// This is used in wxEXEC_NOEVENTS case.
+int BlockUntilChildExit(wxExecuteData& execData)
+{
+ wxCHECK_MSG( wxTheApp, -1,
+ wxS("Can't block until child exit without wxTheApp") );
+
+ // Even if we don't want to dispatch events, we still need to handle
+ // child IO notifications and process termination concurrently, i.e.
+ // we can't simply block waiting for the child to terminate as we would
+ // dead lock if it writes more than the pipe buffer size (typically
+ // 4KB) bytes of output -- it would then block waiting for us to read
+ // the data while we'd block waiting for it to terminate.
+ //
+ // So while we don't use the full blown event loop, we still do use a
+ // dispatcher with which we register just the 3 FDs we're interested
+ // in: the child stdout and stderr and the pipe written to by the
+ // signal handler so that we could react to the child process
+ // termination too.
+
+ // Notice that we must create a new dispatcher object here instead of
+ // reusing the global wxFDIODispatcher::Get() because we want to
+ // monitor only the events on the FDs explicitly registered with this
+ // one and not all the other ones that could be registered with the
+ // global dispatcher (think about the case of nested wxExecute() calls).
+ wxSelectDispatcher dispatcher;
+
+ // Do register all the FDs we want to monitor here: first, the one used to
+ // handle the signals asynchronously.
+ wxScopedPtr<wxFDIOHandler>
+ signalHandler(wxTheApp->RegisterSignalWakeUpPipe(dispatcher));
+
+#if wxUSE_STREAMS
+ // And then the two for the child output and error streams if necessary.
+ wxScopedPtr<wxFDIOHandler>
+ stdoutHandler,
+ stderrHandler;
+ if ( execData.IsRedirected() )
+ {
+ stdoutHandler.reset(new wxExecuteFDIOHandler
+ (
+ dispatcher,
+ execData.fdOut,
+ execData.bufOut
+ ));
+ stderrHandler.reset(new wxExecuteFDIOHandler
+ (
+ dispatcher,
+ execData.fdErr,
+ execData.bufErr
+ ));
+ }
+#endif // wxUSE_STREAMS
+
+ // And dispatch until the PID is reset from wxExecuteData::OnExit().
+ while ( execData.pid )
+ {
+ dispatcher.Dispatch();
+ }
+
+ return execData.exitcode;
+}
+
+} // anonymous namespace
+
// wxExecute: the real worker function
long wxExecute(char **argv, int flags, wxProcess *process,
const wxExecuteEnv *env)
}
#endif // __DARWIN__
-
// this struct contains all information which we use for housekeeping
- wxExecuteData execData;
+ wxScopedPtr<wxExecuteData> execDataPtr(new wxExecuteData);
+ wxExecuteData& execData = *execDataPtr;
+
execData.flags = flags;
execData.process = process;
- // create pipes
- if ( !execData.pipeEndProcDetect.Create() )
- {
- wxLogError( _("Failed to execute '%s'\n"), *argv );
-
- return ERROR_RETURN_CODE;
- }
-
- // pipes for inter process communication
+ // create pipes for inter process communication
wxPipe pipeIn, // stdin
pipeOut, // stdout
pipeErr; // stderr
// the descriptors do not need to be closed but for now this is better
// than never closing them at all as wx code never used FD_CLOEXEC.
- // Note that while the reading side of the end process detection pipe
- // can be safely closed, we should keep the write one opened, it will
- // be only closed when the process terminates resulting in a read
- // notification to the parent
- const int fdEndProc = execData.pipeEndProcDetect.Detach(wxPipe::Write);
- execData.pipeEndProcDetect.Close();
-
// TODO: Iterating up to FD_SETSIZE is both inefficient (because it may
// be quite big) and incorrect (because in principle we could
// have more opened descriptions than this number). Unfortunately
{
if ( fd != STDIN_FILENO &&
fd != STDOUT_FILENO &&
- fd != STDERR_FILENO &&
- fd != fdEndProc )
+ fd != STDERR_FILENO )
{
close(fd);
}
}
else // we're in parent
{
- // save it for WaitForChild() use
- execData.pid = pid;
- if (execData.process)
- execData.process->SetPid(pid); // and also in the wxProcess
+ execData.OnStart(pid);
// prepare for IO redirection
#if HAS_PIPE_STREAMS
- // the input buffer bufOut is connected to stdout, this is why it is
- // called bufOut and not bufIn
- wxStreamTempInputBuffer bufOut,
- bufErr;
if ( process && process->IsRedirected() )
{
process->SetPipeStreams(outStream, inStream, errStream);
- bufOut.Init(outStream);
- bufErr.Init(errStream);
-
- execData.bufOut = &bufOut;
- execData.bufErr = &bufErr;
+ if ( flags & wxEXEC_SYNC )
+ {
+ execData.bufOut.Init(outStream);
+ execData.bufErr.Init(errStream);
- execData.fdOut = fdOut;
- execData.fdErr = fdErr;
+ execData.fdOut = fdOut;
+ execData.fdErr = fdErr;
+ }
}
#endif // HAS_PIPE_STREAMS
pipeErr.Close();
}
- // we want this function to work even if there is no wxApp so ensure
- // that we have a valid traits pointer
- wxConsoleAppTraits traitsConsole;
- wxAppTraits *traits = wxTheApp ? wxTheApp->GetTraits() : NULL;
- if ( !traits )
- traits = &traitsConsole;
+ // For the asynchronous case we don't have to do anything else, just
+ // let the process run.
+ if ( !(flags & wxEXEC_SYNC) )
+ {
+ // Ensure that the housekeeping data is kept alive, it will be
+ // destroyed only when the child terminates.
+ execDataPtr.release();
+
+ return execData.pid;
+ }
+
- return traits->WaitForChild(execData);
+ // If we don't need to dispatch any events, things are relatively
+ // simple and we don't need to delegate to wxAppTraits.
+ if ( flags & wxEXEC_NOEVENTS )
+ {
+ return BlockUntilChildExit(execData);
+ }
+
+
+ // If we do need to dispatch events, enter a local event loop waiting
+ // until the child exits. As the exact kind of event loop depends on
+ // the sort of application we're in (console or GUI), we delegate this
+ // to wxAppTraits which virtualizes all the differences between the
+ // console and the GUI programs.
+ return wxApp::GetValidTraits().WaitForChild(execData);
}
#if !defined(__VMS) && !defined(__INTEL_COMPILER)
// wxExecute support
// ----------------------------------------------------------------------------
-int wxAppTraits::AddProcessCallback(wxEndProcessData *data, int fd)
-{
- // define a custom handler processing only the closure of the descriptor
- struct wxEndProcessFDIOHandler : public wxFDIOHandler
- {
- wxEndProcessFDIOHandler(wxEndProcessData *data, int fd)
- : m_data(data), m_fd(fd)
- {
- }
-
- virtual void OnReadWaiting()
- {
- wxFDIODispatcher::Get()->UnregisterFD(m_fd);
- close(m_fd);
-
- wxHandleProcessTermination(m_data);
-
- delete this;
- }
-
- virtual void OnWriteWaiting() { wxFAIL_MSG("unreachable"); }
- virtual void OnExceptionWaiting() { wxFAIL_MSG("unreachable"); }
-
- wxEndProcessData * const m_data;
- const int m_fd;
- };
-
- wxFDIODispatcher::Get()->RegisterFD
- (
- fd,
- new wxEndProcessFDIOHandler(data, fd),
- wxFDIO_INPUT
- );
- return fd; // unused, but return something unique for the tag
-}
-
-bool wxAppTraits::CheckForRedirectedIO(wxExecuteData& execData)
+int wxAppTraits::WaitForChild(wxExecuteData& execData)
{
-#if HAS_PIPE_STREAMS
- bool hasIO = false;
-
- if ( execData.bufOut && execData.bufOut->Update() )
- hasIO = true;
-
- if ( execData.bufErr && execData.bufErr->Update() )
- hasIO = true;
-
- return hasIO;
-#else // !HAS_PIPE_STREAMS
- wxUnusedVar(execData);
-
- return false;
-#endif // HAS_PIPE_STREAMS/!HAS_PIPE_STREAMS
+ wxConsoleEventLoop loop;
+ return RunLoopUntilChildExit(execData, loop);
}
-// helper classes/functions used by WaitForChild()
-namespace
-{
-
-// convenient base class for IO handlers which are registered for read
-// notifications only and which also stores the FD we're reading from
+// This function is common code for both console and GUI applications and used
+// by wxExecute() to wait for the child exit while dispatching events.
//
-// the derived classes still have to implement OnReadWaiting()
-class wxReadFDIOHandler : public wxFDIOHandler
-{
-public:
- wxReadFDIOHandler(wxFDIODispatcher& disp, int fd) : m_fd(fd)
- {
- if ( fd )
- disp.RegisterFD(fd, this, wxFDIO_INPUT);
- }
-
- virtual void OnWriteWaiting() { wxFAIL_MSG("unreachable"); }
- virtual void OnExceptionWaiting() { wxFAIL_MSG("unreachable"); }
-
-protected:
- const int m_fd;
-
- wxDECLARE_NO_COPY_CLASS(wxReadFDIOHandler);
-};
-
-// class for monitoring our end of the process detection pipe, simply sets a
-// flag when input on the pipe (which must be due to EOF) is detected
-class wxEndHandler : public wxReadFDIOHandler
+// Notice that it should not be used for all the other cases, e.g. when we
+// don't need to wait for the child (wxEXEC_ASYNC) or when the events must not
+// dispatched (wxEXEC_NOEVENTS).
+int
+wxAppTraits::RunLoopUntilChildExit(wxExecuteData& execData,
+ wxEventLoopBase& loop)
{
-public:
- wxEndHandler(wxFDIODispatcher& disp, int fd)
- : wxReadFDIOHandler(disp, fd)
+ // It is possible that wxExecuteData::OnExit() had already been called
+ // and reset the PID to 0, in which case we don't need to do anything
+ // at all.
+ if ( !execData.pid )
+ return execData.exitcode;
+
+#if wxUSE_STREAMS
+ // Monitor the child streams if necessary.
+ wxScopedPtr<wxEventLoopSourceHandler>
+ stdoutHandler,
+ stderrHandler;
+ if ( execData.IsRedirected() )
{
- m_terminated = false;
+ stdoutHandler.reset(new wxExecuteEventLoopSourceHandler
+ (
+ execData.fdOut, execData.bufOut
+ ));
+ stderrHandler.reset(new wxExecuteEventLoopSourceHandler
+ (
+ execData.fdErr, execData.bufErr
+ ));
}
+#endif // wxUSE_STREAMS
- bool Terminated() const { return m_terminated; }
+ // Store the event loop in the data associated with the child
+ // process so that it could exit the loop when the child exits.
+ execData.syncEventLoop = &loop;
- virtual void OnReadWaiting() { m_terminated = true; }
-
-private:
- bool m_terminated;
+ // And run it.
+ loop.Run();
- wxDECLARE_NO_COPY_CLASS(wxEndHandler);
-};
+ // The exit code will have been set when the child termination was detected.
+ return execData.exitcode;
+}
-#if HAS_PIPE_STREAMS
+// ----------------------------------------------------------------------------
+// wxExecuteData
+// ----------------------------------------------------------------------------
-// class for monitoring our ends of child stdout/err, should be constructed
-// with the FD and stream from wxExecuteData and will do nothing if they're
-// invalid
-//
-// unlike wxEndHandler this class registers itself with the provided dispatcher
-class wxRedirectedIOHandler : public wxReadFDIOHandler
+namespace
{
-public:
- wxRedirectedIOHandler(wxFDIODispatcher& disp,
- int fd,
- wxStreamTempInputBuffer *buf)
- : wxReadFDIOHandler(disp, fd),
- m_buf(buf)
- {
- }
-
- virtual void OnReadWaiting()
- {
- m_buf->Update();
- }
-private:
- wxStreamTempInputBuffer * const m_buf;
-
- wxDECLARE_NO_COPY_CLASS(wxRedirectedIOHandler);
-};
-
-#endif // HAS_PIPE_STREAMS
-
-// helper function which calls waitpid() and analyzes the result
-int DoWaitForChild(int pid, int flags = 0)
+// Helper function that checks whether the child with the given PID has exited
+// and fills the provided parameter with its return code if it did.
+bool CheckForChildExit(int pid, int* exitcodeOut)
{
wxASSERT_MSG( pid > 0, "invalid PID" );
// loop while we're getting EINTR
for ( ;; )
{
- rc = waitpid(pid, &status, flags);
+ rc = waitpid(pid, &status, WNOHANG);
if ( rc != -1 || errno != EINTR )
break;
}
- if ( rc == 0 )
- {
- // This can only happen if the child application closes our dummy pipe
- // that is used to monitor its lifetime; in that case, our best bet is
- // to pretend the process did terminate, because otherwise wxExecute()
- // would hang indefinitely (OnReadWaiting() won't be called again, the
- // descriptor is closed now).
- wxLogDebug("Child process (PID %d) still alive but pipe closed so "
- "generating a close notification", pid);
- }
- else if ( rc == -1 )
+ switch ( rc )
{
- wxLogLastError(wxString::Format("waitpid(%d)", pid));
- }
- else // child did terminate
- {
- wxASSERT_MSG( rc == pid, "unexpected waitpid() return value" );
-
- // notice that the caller expects the exit code to be signed, e.g. -1
- // instead of 255 so don't assign WEXITSTATUS() to an int
- signed char exitcode;
- if ( WIFEXITED(status) )
- exitcode = WEXITSTATUS(status);
- else if ( WIFSIGNALED(status) )
- exitcode = -WTERMSIG(status);
- else
- {
- wxLogError("Child process (PID %d) exited for unknown reason, "
- "status = %d", pid, status);
- exitcode = -1;
- }
+ case 0:
+ // No error but the child is still running.
+ return false;
- return exitcode;
- }
+ case -1:
+ // Checking child status failed. Invalid PID?
+ wxLogLastError(wxString::Format("waitpid(%d)", pid));
+ return false;
- return -1;
+ default:
+ // Child did terminate.
+ wxASSERT_MSG( rc == pid, "unexpected waitpid() return value" );
+
+ // notice that the caller expects the exit code to be signed, e.g. -1
+ // instead of 255 so don't assign WEXITSTATUS() to an int
+ signed char exitcode;
+ if ( WIFEXITED(status) )
+ exitcode = WEXITSTATUS(status);
+ else if ( WIFSIGNALED(status) )
+ exitcode = -WTERMSIG(status);
+ else
+ {
+ wxLogError("Child process (PID %d) exited for unknown reason, "
+ "status = %d", pid, status);
+ exitcode = -1;
+ }
+
+ if ( exitcodeOut )
+ *exitcodeOut = exitcode;
+
+ return true;
+ }
}
} // anonymous namespace
-int wxAppTraits::WaitForChild(wxExecuteData& execData)
+wxExecuteData::ChildProcessesData wxExecuteData::ms_childProcesses;
+
+/* static */
+void wxExecuteData::OnSomeChildExited(int WXUNUSED(sig))
{
- if ( !(execData.flags & wxEXEC_SYNC) )
- {
- // asynchronous execution: just launch the process and return,
- // endProcData will be destroyed when it terminates (currently we leak
- // it if the process doesn't terminate before we do and this should be
- // fixed but it's not a real leak so it's not really very high
- // priority)
- wxEndProcessData *endProcData = new wxEndProcessData;
- endProcData->process = execData.process;
- endProcData->pid = execData.pid;
- endProcData->tag = AddProcessCallback
- (
- endProcData,
- execData.GetEndProcReadFD()
- );
- endProcData->async = true;
-
- return execData.pid;
- }
- //else: synchronous execution case
+ // We know that some child process has terminated, but we don't know which
+ // one, so check all of them (notice that more than one could have exited).
+ //
+ // An alternative approach would be to call waitpid(-1, &status, WNOHANG)
+ // (in a loop to take care of the multiple children exiting case) and
+ // perhaps this would be more efficient. But for now this seems to work.
-#if HAS_PIPE_STREAMS && wxUSE_SOCKETS
- wxProcess * const process = execData.process;
- if ( process && process->IsRedirected() )
+
+ // Make a copy of the list before iterating over it to avoid problems due
+ // to deleting entries from it in the process.
+ const ChildProcessesData allChildProcesses = ms_childProcesses;
+ for ( ChildProcessesData::const_iterator it = allChildProcesses.begin();
+ it != allChildProcesses.end();
+ ++it )
{
- // we can't simply block waiting for the child to terminate as we would
- // dead lock if it writes more than the pipe buffer size (typically
- // 4KB) bytes of output -- it would then block waiting for us to read
- // the data while we'd block waiting for it to terminate
+ const int pid = it->first;
+
+ // Check whether this child exited.
+ int exitcode;
+ if ( !CheckForChildExit(pid, &exitcode) )
+ continue;
+
+ // And handle its termination if it did.
//
- // so multiplex here waiting for any input from the child or closure of
- // the pipe used to indicate its termination
- wxSelectDispatcher disp;
+ // Notice that this will implicitly remove it from ms_childProcesses.
+ it->second->OnExit(exitcode);
+ }
+}
- wxEndHandler endHandler(disp, execData.GetEndProcReadFD());
+void wxExecuteData::OnStart(int pid_)
+{
+ wxCHECK_RET( wxTheApp,
+ wxS("Ensure wxTheApp is set before calling wxExecute()") );
- wxRedirectedIOHandler outHandler(disp, execData.fdOut, execData.bufOut),
- errHandler(disp, execData.fdErr, execData.bufErr);
+ // Setup the signal handler for SIGCHLD to be able to detect the child
+ // termination.
+ //
+ // Notice that SetSignalHandler() is idempotent, so it's fine to call
+ // it more than once with the same handler.
+ wxTheApp->SetSignalHandler(SIGCHLD, OnSomeChildExited);
- while ( !endHandler.Terminated() )
- {
- disp.Dispatch();
- }
- }
- //else: no IO redirection, just block waiting for the child to exit
-#endif // HAS_PIPE_STREAMS
- return DoWaitForChild(execData.pid);
+ // Remember the child PID to be able to wait for it later.
+ pid = pid_;
+
+ // Also save it in wxProcess where it will be accessible to the user code.
+ if ( process )
+ process->SetPid(pid);
+
+ // Finally, add this object itself to the list of child processes so that
+ // we can check for its termination the next time we get SIGCHLD.
+ ms_childProcesses[pid] = this;
}
-void wxHandleProcessTermination(wxEndProcessData *data)
+void wxExecuteData::OnExit(int exitcode_)
{
- data->exitcode = DoWaitForChild(data->pid, WNOHANG);
+ // Remove this process from the hash list of child processes that are
+ // still open as soon as possible to ensure we don't process it again even
+ // if another SIGCHLD happens.
+ if ( !ms_childProcesses.erase(pid) )
+ {
+ wxFAIL_MSG(wxString::Format(wxS("Data for PID %d not in the list?"), pid));
+ }
+
- // notify user about termination if required
- if ( data->process )
+ exitcode = exitcode_;
+
+#if wxUSE_STREAMS
+ if ( IsRedirected() )
{
- data->process->OnTerminate(data->pid, data->exitcode);
+ // Read the remaining data in a blocking way: this is fine because the
+ // child has already exited and hence all the data must be already
+ // available in the streams buffers.
+ bufOut.ReadAll();
+ bufErr.ReadAll();
}
+#endif // wxUSE_STREAMS
- if ( data->async )
+ // Notify user about termination if required
+ if ( !(flags & wxEXEC_SYNC) )
{
- // in case of asynchronous execution we don't need this data any more
+ if ( process )
+ process->OnTerminate(pid, exitcode);
+
+ // in case of asynchronous execution we don't need this object any more
// after the child terminates
- delete data;
+ delete this;
}
else // sync execution
{
// let wxExecute() know that the process has terminated
- data->pid = 0;
+ pid = 0;
+
+ // Stop the event loop for synchronous wxExecute() if we're running one.
+ if ( syncEventLoop )
+ syncEventLoop->ScheduleExit();
}
}
-
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