1/* Serial interface for a pipe to a separate program
2   Copyright (C) 1999, 2000, 2001, 2007 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 3 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, see <http://www.gnu.org/licenses/>.  */
20
21#include "defs.h"
22#include "serial.h"
23#include "ser-base.h"
24#include "ser-unix.h"
25
26#include "gdb_vfork.h"
27
28#include <sys/types.h>
29#include <sys/socket.h>
30#include <sys/time.h>
31#include <fcntl.h>
32#include "gdb_string.h"
33
34#include <signal.h>
35
36static int pipe_open (struct serial *scb, const char *name);
37static void pipe_close (struct serial *scb);
38
39extern void _initialize_ser_pipe (void);
40
41struct pipe_state
42  {
43    int pid;
44  };
45
46/* Open up a raw pipe */
47
48static int
49pipe_open (struct serial *scb, const char *name)
50{
51#if !HAVE_SOCKETPAIR
52  return -1;
53#else
54  struct pipe_state *state;
55  /* This chunk: */
56  /* Copyright (c) 1988, 1993
57   *      The Regents of the University of California.  All rights reserved.
58   *
59   * This code is derived from software written by Ken Arnold and
60   * published in UNIX Review, Vol. 6, No. 8.
61   */
62  int pdes[2];
63  int err_pdes[2];
64  int pid;
65  if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
66    return -1;
67  if (socketpair (AF_UNIX, SOCK_STREAM, 0, err_pdes) < 0)
68    return -1;
69
70  /* Create the child process to run the command in.  Note that the
71     apparent call to vfork() below *might* actually be a call to
72     fork() due to the fact that autoconf will ``#define vfork fork''
73     on certain platforms.  */
74  pid = vfork ();
75
76  /* Error. */
77  if (pid == -1)
78    {
79      close (pdes[0]);
80      close (pdes[1]);
81      close (err_pdes[0]);
82      close (err_pdes[1]);
83      return -1;
84    }
85
86  if (fcntl (err_pdes[0], F_SETFL, O_NONBLOCK) == -1)
87    {
88      close (err_pdes[0]);
89      close (err_pdes[1]);
90      err_pdes[0] = err_pdes[1] = -1;
91    }
92
93  /* Child. */
94  if (pid == 0)
95    {
96      /* re-wire pdes[1] to stdin/stdout */
97      close (pdes[0]);
98      if (pdes[1] != STDOUT_FILENO)
99	{
100	  dup2 (pdes[1], STDOUT_FILENO);
101	  close (pdes[1]);
102	}
103      dup2 (STDOUT_FILENO, STDIN_FILENO);
104
105      if (err_pdes[0] != -1)
106	{
107	  close (err_pdes[0]);
108	  dup2 (err_pdes[1], STDERR_FILENO);
109	  close (err_pdes[1]);
110	}
111#if 0
112      /* close any stray FD's - FIXME - how? */
113      /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
114         from previous popen() calls that remain open in the
115         parent process are closed in the new child process. */
116      for (old = pidlist; old; old = old->next)
117	close (fileno (old->fp));	/* don't allow a flush */
118#endif
119      execl ("/bin/sh", "sh", "-c", name, (char *) 0);
120      _exit (127);
121    }
122
123  /* Parent. */
124  close (pdes[1]);
125  /* :end chunk */
126  state = XMALLOC (struct pipe_state);
127  state->pid = pid;
128  scb->fd = pdes[0];
129  scb->error_fd = err_pdes[0];
130  scb->state = state;
131
132  /* If we don't do this, GDB simply exits when the remote side dies.  */
133  signal (SIGPIPE, SIG_IGN);
134  return 0;
135#endif
136}
137
138static void
139pipe_close (struct serial *scb)
140{
141  struct pipe_state *state = scb->state;
142  if (state != NULL)
143    {
144      int pid = state->pid;
145      close (scb->fd);
146      scb->fd = -1;
147      xfree (state);
148      scb->state = NULL;
149      kill (pid, SIGTERM);
150      /* Might be useful to check that the child does die. */
151    }
152}
153
154static struct serial_ops pipe_ops;
155
156void
157_initialize_ser_pipe (void)
158{
159  struct serial_ops *ops = XMALLOC (struct serial_ops);
160  memset (ops, 0, sizeof (struct serial_ops));
161  ops->name = "pipe";
162  ops->next = 0;
163  ops->open = pipe_open;
164  ops->close = pipe_close;
165  ops->readchar = ser_base_readchar;
166  ops->write = ser_base_write;
167  ops->flush_output = ser_base_flush_output;
168  ops->flush_input = ser_base_flush_input;
169  ops->send_break = ser_base_send_break;
170  ops->go_raw = ser_base_raw;
171  ops->get_tty_state = ser_base_get_tty_state;
172  ops->set_tty_state = ser_base_set_tty_state;
173  ops->print_tty_state = ser_base_print_tty_state;
174  ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;
175  ops->setbaudrate = ser_base_setbaudrate;
176  ops->setstopbits = ser_base_setstopbits;
177  ops->drain_output = ser_base_drain_output;
178  ops->async = ser_base_async;
179  ops->read_prim = ser_unix_read_prim;
180  ops->write_prim = ser_unix_write_prim;
181  serial_add_interface (ops);
182}
183