/*

Copyright (C) 1996-2015 John W. Eaton

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

Octave is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include <cerrno>
#include <cstdlib>

#include <string.h>

#include <sys/types.h>
#include <unistd.h>

#include <fcntl.h>

// We can't use csignal as kill is not in the std namespace, and picky
// compiler runtimes will also exclude it from global scope as well.

#include <signal.h>

#include "lo-utils.h"
#include "lo-sysdep.h"
#include "oct-syscalls.h"
#include "str-vec.h"

#define NOT_SUPPORTED(nm) \
  nm ": not supported on this system"

namespace octave
{
  namespace
  syscalls
  {
    int
    dup2 (int old_fd, int new_fd)
    {
      std::string msg;
      return octave::syscalls::dup2 (old_fd, new_fd, msg);
    }

    int
    dup2 (int old_fd, int new_fd, std::string& msg)
    {
      msg = "";

      int status = -1;

#if defined (HAVE_DUP2)
      status = gnulib::dup2 (old_fd, new_fd);

      if (status < 0)
        msg = gnulib::strerror (errno);
#else
      msg = NOT_SUPPORTED ("dup2");
#endif

      return status;
    }

    int
    execvp (const std::string& file, const string_vector& argv)
    {
      std::string msg;
      return octave::syscalls::execvp (file, argv, msg);
    }

    int
    execvp (const std::string& file, const string_vector& args,
            std::string& msg)
    {
      msg = "";

      int status = -1;

#if defined (HAVE_EXECVP)
      char **argv = args.c_str_vec ();

      status = ::execvp (file.c_str (), argv);

      string_vector::delete_c_str_vec (argv);

      if (status < 0)
        msg = gnulib::strerror (errno);
#else
      msg = NOT_SUPPORTED ("execvp");
#endif

      return status;
    }

    pid_t
    fork (std::string& msg)
    {
      pid_t status = -1;

#if defined (HAVE_FORK)
      status = ::fork ();

      if (status < 0)
        msg = gnulib::strerror (errno);
#else
      msg = NOT_SUPPORTED ("fork");
#endif

      return status;
    }

    pid_t
    vfork (std::string& msg)
    {
      pid_t status = -1;

#if defined (HAVE_VFORK) || defined (HAVE_FORK)
#  if defined (HAVE_VFORK)
      status = ::vfork ();
#  else
      status = ::fork ();
#  endif

      if (status < 0)
        msg = gnulib::strerror (errno);
#else
      msg = NOT_SUPPORTED ("vfork");
#endif

      return status;
    }

    pid_t
    getpgrp (std::string& msg)
    {
      pid_t status = -1;

#if defined (HAVE_GETPGRP)
      status = ::getpgrp ();

      if (status < 0)
        msg = gnulib::strerror (errno);
#else
      msg = NOT_SUPPORTED ("getpgrp");
#endif

      return status;
    }

    pid_t
    getpid (void)
    {
#if defined (HAVE_GETPID)
      return ::getpid ();
#else
      return 0;
#endif
    }

    pid_t
    getppid (void)
    {
#if defined (HAVE_GETPPID)
      return ::getppid ();
#else
      return 0;
#endif
    }

    gid_t
    getgid (void)
    {
#if defined (HAVE_GETGID)
      return ::getgid ();
#else
      return 0;
#endif
    }

    gid_t
    getegid (void)
    {
#if defined (HAVE_GETEGID)
      return ::getegid ();
#else
      return 0;
#endif
    }

    uid_t
    getuid (void)
    {
#if defined (HAVE_GETUID)
      return ::getuid ();
#else
      return 0;
#endif
    }

    uid_t
    geteuid (void)
    {
#if defined (HAVE_GETEUID)
      return ::geteuid ();
#else
      return 0;
#endif
    }

    int
    pipe (int *fildes)
    {
      std::string msg;
      return octave::syscalls::pipe (fildes, msg);
    }

    int
    pipe (int *fildes, std::string& msg)
    {
      msg = "";

      int status = -1;

      status = gnulib::pipe (fildes);

      if (status < 0)
        msg = gnulib::strerror (errno);

      return status;
    }

    pid_t
    waitpid (pid_t pid, int *status, int options)
    {
      std::string msg;
      return octave::syscalls::waitpid (pid, status, options, msg);
    }

    pid_t
    waitpid (pid_t pid, int *status, int options,
             std::string& msg)
    {
      pid_t retval = -1;
      msg = "";

#if defined (HAVE_WAITPID)
      retval = ::octave_waitpid (pid, status, options);

      if (retval < 0)
        msg = gnulib::strerror (errno);
#else
      msg = NOT_SUPPORTED ("waitpid");
#endif

      return retval;
    }

    int
    kill (pid_t pid, int sig)
    {
      std::string msg;
      return octave::syscalls::kill (pid, sig, msg);
    }

    int
    kill (pid_t pid, int sig, std::string& msg)
    {
      msg = "";

      int status = -1;

#if defined (HAVE_KILL)
      status = ::kill (pid, sig);

      if (status < 0)
        msg = gnulib::strerror (errno);
#else
      msg = NOT_SUPPORTED ("kill");
#endif

      return status;
    }

    pid_t
    popen2 (const std::string& cmd, const string_vector& args,
            bool sync_mode, int *fildes)
    {
      std::string msg;
      bool interactive = false;
      return octave::syscalls::popen2 (cmd, args, sync_mode, fildes, msg,
                                       interactive);
    }

    pid_t
    popen2 (const std::string& cmd, const string_vector& args,
            bool sync_mode, int *fildes, std::string& msg)
    {
      bool interactive = false;
      return octave::syscalls::popen2 (cmd, args, sync_mode, fildes, msg,
                                       interactive);
    }

    pid_t
    popen2 (const std::string& cmd, const string_vector& args,
            bool sync_mode, int *fildes, std::string& msg,
            bool &interactive)
    {
#if defined (__WIN32__) && ! defined (__CYGWIN__)
      return ::octave_popen2 (cmd, args, sync_mode, fildes, msg);
#else
      pid_t pid;
      int child_stdin[2], child_stdout[2];

      if (pipe (child_stdin, msg) == 0)
        {
          if (pipe (child_stdout, msg) == 0)
            {
              pid = fork (msg);
              if (pid < 0)
                msg = "popen2: process creation failed -- " + msg;
              else if (pid == 0)
                {
                  std::string child_msg;

                  interactive = false;

                  // Child process
                  gnulib::close (child_stdin[1]);
                  gnulib::close (child_stdout[0]);

                  if (dup2 (child_stdin[0], STDIN_FILENO) >= 0)
                    {
                      gnulib::close (child_stdin[0]);
                      if (dup2 (child_stdout[1], STDOUT_FILENO) >= 0)
                        {
                          gnulib::close (child_stdout[1]);
                          if (execvp (cmd, args, child_msg) < 0)
                            child_msg = "popen2 (child): unable to start process -- " + child_msg;
                        }
                      else
                        child_msg = "popen2 (child): file handle duplication failed -- " + child_msg;
                    }
                  else
                    child_msg = "popen2 (child): file handle duplication failed -- " + child_msg;

                  (*current_liboctave_error_handler) (child_msg.c_str ());

                  exit (0);
                }
              else
                {
                  // Parent process
                  gnulib::close (child_stdin[0]);
                  gnulib::close (child_stdout[1]);

#if defined (F_SETFL) && defined (O_NONBLOCK)
                  if (! sync_mode
                      && octave::syscalls::fcntl (child_stdout[0], F_SETFL,
                                                  O_NONBLOCK, msg) < 0)
                    msg = "popen2: error setting file mode -- " + msg;
                  else
#endif
                    {
                      fildes[0] = child_stdin[1];
                      fildes[1] = child_stdout[0];
                      return pid;
                    }
                }
              gnulib::close (child_stdout[0]);
              gnulib::close (child_stdout[1]);
            }
          else
            msg = "popen2: pipe creation failed -- " + msg;

          gnulib::close (child_stdin[0]);
          gnulib::close (child_stdin[1]);
        }
      else
        msg = "popen2: pipe creation failed -- " + msg;

      return -1;
#endif
    }

    int
    fcntl (int fd, int cmd, long arg)
    {
      std::string msg;
      return octave::syscalls::fcntl (fd, cmd, arg, msg);
    }

    int
    fcntl (int fd, int cmd, long arg, std::string& msg)
    {
      msg = "";

      int status = -1;

      status = gnulib::fcntl (fd, cmd, arg);

      if (status < 0)
        msg = gnulib::strerror (errno);

      return status;
    }
  }
}