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 #ifdef HAVE_VFORK
  68   pid = vfork ();
  69 #else
  70   pid = fork ();
  71 #endif
  72
  73   /* Error. */
  74   if (pid == -1)
  75     {
  76       close (pdes[0]);
  77       close (pdes[1]);
  78       return -1;
  79     }
  80
  81   /* Child. */
  82   if (pid == 0)
  83     {
  84       /* re-wire pdes[1] to stdin/stdout */
  85       close (pdes[0]);
  86       if (pdes[1] != STDOUT_FILENO)
  87         {
  88           dup2 (pdes[1], STDOUT_FILENO);
  89           close (pdes[1]);
  90         }
  91       dup2 (STDOUT_FILENO, STDIN_FILENO);
  92 #if 0
  93       /* close any stray FD's - FIXME - how? */
  94       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
  95          from previous popen() calls that remain open in the
  96          parent process are closed in the new child process. */
  97       for (old = pidlist; old; old = old->next)
  98         close (fileno (old->fp));       /* don't allow a flush */
  99 #endif
 100       execl ("/bin/sh", "sh", "-c", name, NULL);
 101       _exit (127);
 102     }
 103
 104   /* Parent. */
 105   close (pdes[1]);
 106   /* :end chunk */
 107   state = XMALLOC (struct pipe_state);
 108   state->pid = pid;
 109   scb->fd = pdes[0];
 110   scb->state = state;
 111
 112   /* If we don't do this, GDB simply exits when the remote side dies.  */
 113   signal (SIGPIPE, SIG_IGN);
 114   return 0;
 115 #endif
 116 }
 117
 118 static void
 119 pipe_close (serial_t scb)
 120 {
 121   struct pipe_state *state = scb->state;
 122   if (state != NULL)
 123     {
 124       int pid = state->pid;
 125       close (scb->fd);
 126       scb->fd = -1;
 127       xfree (state);
 128       scb->state = NULL;
 129       kill (pid, SIGTERM);
 130       /* Might be useful to check that the child does die. */
 131     }
 132 }
 133
 134 static struct serial_ops pipe_ops;
 135
 136 void
 137 _initialize_ser_pipe (void)
 138 {
 139   struct serial_ops *ops = XMALLOC (struct serial_ops);
 140   memset (ops, sizeof (struct serial_ops), 0);
 141   ops->name = "pipe";
 142   ops->next = 0;
 143   ops->open = pipe_open;
 144   ops->close = pipe_close;
 145   ops->readchar = ser_unix_readchar;
 146   ops->write = ser_unix_write;
 147   ops->flush_output = ser_unix_nop_flush_output;
 148   ops->flush_input = ser_unix_flush_input;
 149   ops->send_break = ser_unix_nop_send_break;
 150   ops->go_raw = ser_unix_nop_raw;
 151   ops->get_tty_state = ser_unix_nop_get_tty_state;
 152   ops->set_tty_state = ser_unix_nop_set_tty_state;
 153   ops->print_tty_state = ser_unix_nop_print_tty_state;
 154   ops->noflush_set_tty_state = ser_unix_nop_noflush_set_tty_state;
 155   ops->setbaudrate = ser_unix_nop_setbaudrate;
 156   ops->setstopbits = ser_unix_nop_setstopbits;
 157   ops->drain_output = ser_unix_nop_drain_output;
 158   ops->async = ser_unix_async;
 159   serial_add_interface (ops);
 160 }