1/* Serial interface for a pipe to a separate program
2   Copyright 1999, 2000, 2001 Free Software Foundation, Inc.
3
4   Contributed by Cygnus Solutions.
5
6   This file is part of GDB.
7
8   This program is free software; you can redistribute it and/or modify
9   it under the terms of the GNU General Public License as published by
10   the Free Software Foundation; either version 2 of the License, or
11   (at your option) any later version.
12
13   This program is distributed in the hope that it will be useful,
14   but WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16   GNU General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with this program; if not, write to the Free Software
20   Foundation, Inc., 59 Temple Place - Suite 330,
21   Boston, MA 02111-1307, USA.  */
22
23#include "defs.h"
24#include "serial.h"
25#include "ser-unix.h"
26
27#include "gdb_vfork.h"
28
29#include <sys/types.h>
30#include <sys/socket.h>
31#include <sys/time.h>
32#include <fcntl.h>
33#include "gdb_string.h"
34
35#include <signal.h>
36
37static int pipe_open (struct serial *scb, const char *name);
38static void pipe_close (struct serial *scb);
39
40extern void _initialize_ser_pipe (void);
41
42struct pipe_state
43  {
44    int pid;
45  };
46
47/* Open up a raw pipe */
48
49static int
50pipe_open (struct serial *scb, const char *name)
51{
52#if !HAVE_SOCKETPAIR
53  return -1;
54#else
55  struct pipe_state *state;
56  /* This chunk: */
57  /* Copyright (c) 1988, 1993
58   *      The Regents of the University of California.  All rights reserved.
59   *
60   * This code is derived from software written by Ken Arnold and
61   * published in UNIX Review, Vol. 6, No. 8.
62   */
63  int pdes[2];
64  int pid;
65  if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
66    return -1;
67
68  /* Create the child process to run the command in.  Note that the
69     apparent call to vfork() below *might* actually be a call to
70     fork() due to the fact that autoconf will ``#define vfork fork''
71     on certain platforms.  */
72  pid = vfork ();
73
74  /* Error. */
75  if (pid == -1)
76    {
77      close (pdes[0]);
78      close (pdes[1]);
79      return -1;
80    }
81
82  /* Child. */
83  if (pid == 0)
84    {
85      /* re-wire pdes[1] to stdin/stdout */
86      close (pdes[0]);
87      if (pdes[1] != STDOUT_FILENO)
88	{
89	  dup2 (pdes[1], STDOUT_FILENO);
90	  close (pdes[1]);
91	}
92      dup2 (STDOUT_FILENO, STDIN_FILENO);
93#if 0
94      /* close any stray FD's - FIXME - how? */
95      /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
96         from previous popen() calls that remain open in the
97         parent process are closed in the new child process. */
98      for (old = pidlist; old; old = old->next)
99	close (fileno (old->fp));	/* don't allow a flush */
100#endif
101      execl ("/bin/sh", "sh", "-c", name, (char *) 0);
102      _exit (127);
103    }
104
105  /* Parent. */
106  close (pdes[1]);
107  /* :end chunk */
108  state = XMALLOC (struct pipe_state);
109  state->pid = pid;
110  scb->fd = pdes[0];
111  scb->state = state;
112
113  /* If we don't do this, GDB simply exits when the remote side dies.  */
114  signal (SIGPIPE, SIG_IGN);
115  return 0;
116#endif
117}
118
119static void
120pipe_close (struct serial *scb)
121{
122  struct pipe_state *state = scb->state;
123  if (state != NULL)
124    {
125      int pid = state->pid;
126      close (scb->fd);
127      scb->fd = -1;
128      xfree (state);
129      scb->state = NULL;
130      kill (pid, SIGTERM);
131      /* Might be useful to check that the child does die. */
132    }
133}
134
135static struct serial_ops pipe_ops;
136
137void
138_initialize_ser_pipe (void)
139{
140  struct serial_ops *ops = XMALLOC (struct serial_ops);
141  memset (ops, 0, sizeof (struct serial_ops));
142  ops->name = "pipe";
143  ops->next = 0;
144  ops->open = pipe_open;
145  ops->close = pipe_close;
146  ops->readchar = ser_unix_readchar;
147  ops->write = ser_unix_write;
148  ops->flush_output = ser_unix_nop_flush_output;
149  ops->flush_input = ser_unix_flush_input;
150  ops->send_break = ser_unix_nop_send_break;
151  ops->go_raw = ser_unix_nop_raw;
152  ops->get_tty_state = ser_unix_nop_get_tty_state;
153  ops->set_tty_state = ser_unix_nop_set_tty_state;
154  ops->print_tty_state = ser_unix_nop_print_tty_state;
155  ops->noflush_set_tty_state = ser_unix_nop_noflush_set_tty_state;
156  ops->setbaudrate = ser_unix_nop_setbaudrate;
157  ops->setstopbits = ser_unix_nop_setstopbits;
158  ops->drain_output = ser_unix_nop_drain_output;
159  ops->async = ser_unix_async;
160  serial_add_interface (ops);
161}
162