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/* Serial interface for a pipe to a separate program

   Copyright (C) 1999, 2000, 2001, 2007, 2008, 2009, 2010

   Free Software Foundation, Inc.

   Contributed by Cygnus Solutions.

   This file is part of GDB.

   This program 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.

   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "serial.h"

#include "ser-base.h"

#include "ser-unix.h"

#include "gdb_vfork.h"

#include <sys/types.h>

#include <sys/socket.h>

#include <sys/time.h>

#include <fcntl.h>

#include "gdb_string.h"

#include <signal.h>

static int pipe_open (struct serial *scb, const char *name);

static void pipe_close (struct serial *scb);

extern void _initialize_ser_pipe (void);

struct pipe_state

  {

    int pid;

  };

/* Open up a raw pipe */

static int

pipe_open (struct serial *scb, const char *name)

{

#if !HAVE_SOCKETPAIR

  return -1;

#else

  struct pipe_state *state;

  /* This chunk: */

  /* Copyright (c) 1988, 1993

   *      The Regents of the University of California.  All rights reserved.

   *

   * This code is derived from software written by Ken Arnold and

   * published in UNIX Review, Vol. 6, No. 8.

   */

  int pdes[2];

  int err_pdes[2];

  int pid;

  if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)

    return -1;

  if (socketpair (AF_UNIX, SOCK_STREAM, 0, err_pdes) < 0)

    {

      close (pdes[0]);

      close (pdes[1]);

      return -1;

    }

  /* Create the child process to run the command in.  Note that the

     apparent call to vfork() below *might* actually be a call to

     fork() due to the fact that autoconf will ``#define vfork fork''

     on certain platforms.  */

  pid = vfork ();

  /* Error. */

  if (pid == -1)

    {

      close (pdes[0]);

      close (pdes[1]);

      close (err_pdes[0]);

      close (err_pdes[1]);

      return -1;

    }

  if (fcntl (err_pdes[0], F_SETFL, O_NONBLOCK) == -1)

    {

      close (err_pdes[0]);

      close (err_pdes[1]);

      err_pdes[0] = err_pdes[1] = -1;

    }

  /* Child. */

  if (pid == 0)

    {

      /* We don't want ^c to kill the connection.  */

#ifdef HAVE_SETSID

      pid_t sid = setsid ();

      if (sid == -1)

        signal (SIGINT, SIG_IGN);

#else

      signal (SIGINT, SIG_IGN);

#endif

      /* re-wire pdes[1] to stdin/stdout */

      close (pdes[0]);

      if (pdes[1] != STDOUT_FILENO)

        {

          dup2 (pdes[1], STDOUT_FILENO);

          close (pdes[1]);

        }

      dup2 (STDOUT_FILENO, STDIN_FILENO);

      if (err_pdes[0] != -1)

        {

          close (err_pdes[0]);

          dup2 (err_pdes[1], STDERR_FILENO);

          close (err_pdes[1]);

        }

#if 0

      /* close any stray FD's - FIXME - how? */

      /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams

         from previous popen() calls that remain open in the

         parent process are closed in the new child process. */

      for (old = pidlist; old; old = old->next)

        close (fileno (old->fp));       /* don't allow a flush */

#endif

      execl ("/bin/sh", "sh", "-c", name, (char *) 0);

      _exit (127);

    }

  /* Parent. */

  close (pdes[1]);

  if (err_pdes[1] != -1)

    close (err_pdes[1]);

  /* :end chunk */

  state = XMALLOC (struct pipe_state);

  state->pid = pid;

  scb->fd = pdes[0];

  scb->error_fd = err_pdes[0];

  scb->state = state;

  /* If we don't do this, GDB simply exits when the remote side dies.  */

  signal (SIGPIPE, SIG_IGN);

  return 0;

#endif

}

static void

pipe_close (struct serial *scb)

{

  struct pipe_state *state = scb->state;

  if (state != NULL)

    {

      int pid = state->pid;

      close (scb->fd);

      scb->fd = -1;

      if (scb->error_fd != -1)

        close (scb->error_fd);

      scb->error_fd = -1;

      xfree (state);

      scb->state = NULL;

      kill (pid, SIGTERM);

      /* Might be useful to check that the child does die,

         and while we're waiting for it to die print any remaining

         stderr output.  */

    }

}

void

_initialize_ser_pipe (void)

{

  struct serial_ops *ops = XMALLOC (struct serial_ops);

  memset (ops, 0, sizeof (struct serial_ops));

  ops->name = "pipe";

  ops->next = 0;

  ops->open = pipe_open;

  ops->close = pipe_close;

  ops->readchar = ser_base_readchar;

  ops->write = ser_base_write;

  ops->flush_output = ser_base_flush_output;

  ops->flush_input = ser_base_flush_input;

  ops->send_break = ser_base_send_break;

  ops->go_raw = ser_base_raw;

  ops->get_tty_state = ser_base_get_tty_state;

  ops->set_tty_state = ser_base_set_tty_state;

  ops->print_tty_state = ser_base_print_tty_state;

  ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;

  ops->setbaudrate = ser_base_setbaudrate;

  ops->setstopbits = ser_base_setstopbits;

  ops->drain_output = ser_base_drain_output;

  ops->async = ser_base_async;

  ops->read_prim = ser_unix_read_prim;

  ops->write_prim = ser_unix_write_prim;

  serial_add_interface (ops);

}