gdb/ser-pipe.c

   1 /* Serial interface for a pipe to a separate program
   2    Copyright 1999 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 <sys/types.h>
  28 #include "gdb_wait.h"
  29 #include <sys/socket.h>
  30 #include <sys/time.h>
  31 #include <fcntl.h>
  32 #include <string.h>
  33
  34 #include "signals.h"
  35
  36 static int pipe_open (serial_t scb, const char *name);
  37 static void pipe_close (serial_t scb);
  38
  39 extern void _initialize_ser_pipe (void);
  40
  41 struct pipe_state
  42   {
  43     int pid;
  44   };
  45
  46 /* Open up a raw pipe */
  47
  48 static int
  49 pipe_open (serial_t 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 pid;
  64   if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
  65     return -1;
  66
  67   pid = vfork ();
  68
  69   /* Error. */
  70   if (pid == -1)
  71     {
  72       close (pdes[0]);
  73       close (pdes[1]);
  74       return -1;
  75     }
  76
  77   /* Child. */
  78   if (pid == 0)
  79     {
  80       /* re-wire pdes[1] to stdin/stdout */
  81       close (pdes[0]);
  82       if (pdes[1] != STDOUT_FILENO)
  83         {
  84           dup2 (pdes[1], STDOUT_FILENO);
  85           close (pdes[1]);
  86         }
  87       dup2 (STDOUT_FILENO, STDIN_FILENO);
  88 #if 0
  89       /* close any stray FD's - FIXME - how? */
  90       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
  91          from previous popen() calls that remain open in the
  92          parent process are closed in the new child process. */
  93       for (old = pidlist; old; old = old->next)
  94         close (fileno (old->fp));       /* don't allow a flush */
  95 #endif
  96       execl ("/bin/sh", "sh", "-c", name, NULL);
  97       _exit (127);
  98     }
  99
 100   /* Parent. */
 101   close (pdes[1]);
 102   /* :end chunk */
 103   state = XMALLOC (struct pipe_state);
 104   state->pid = pid;
 105   scb->fd = pdes[0];
 106   scb->state = state;
 107
 108   /* If we don't do this, GDB simply exits when the remote side dies.  */
 109   signal (SIGPIPE, SIG_IGN);
 110   return 0;
 111 #endif
 112 }
 113
 114 static void
 115 pipe_close (serial_t scb)
 116 {
 117   struct pipe_state *state = scb->state;
 118   if (state != NULL)
 119     {
 120       int pid = state->pid;
 121       close (scb->fd);
 122       scb->fd = -1;
 123       free (state);
 124       scb->state = NULL;
 125       kill (pid, SIGTERM);
 126       /* Might be useful to check that the child does die. */
 127     }
 128 }
 129
 130 static struct serial_ops pipe_ops;
 131
 132 void
 133 _initialize_ser_pipe (void)
 134 {
 135   struct serial_ops *ops = XMALLOC (struct serial_ops);
 136   memset (ops, sizeof (struct serial_ops), 0);
 137   ops->name = "pipe";
 138   ops->next = 0;
 139   ops->open = pipe_open;
 140   ops->close = pipe_close;
 141   ops->readchar = ser_unix_readchar;
 142   ops->write = ser_unix_write;
 143   ops->flush_output = ser_unix_nop_flush_output;
 144   ops->flush_input = ser_unix_flush_input;
 145   ops->send_break = ser_unix_nop_send_break;
 146   ops->go_raw = ser_unix_nop_raw;
 147   ops->get_tty_state = ser_unix_nop_get_tty_state;
 148   ops->set_tty_state = ser_unix_nop_set_tty_state;
 149   ops->print_tty_state = ser_unix_nop_print_tty_state;
 150   ops->noflush_set_tty_state = ser_unix_nop_noflush_set_tty_state;
 151   ops->setbaudrate = ser_unix_nop_setbaudrate;
 152   ops->setstopbits = ser_unix_nop_setstopbits;
 153   ops->drain_output = ser_unix_nop_drain_output;
 154   ops->async = ser_unix_async;
 155   serial_add_interface (ops);
 156 }