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 "gdb_vfork.h"
  28
  29 #include <sys/types.h>
  30 #include "gdb_wait.h"
  31 #include <sys/socket.h>
  32 #include <sys/time.h>
  33 #include <fcntl.h>
  34 #include <string.h>
  35
  36 #include "signals.h"
  37
  38 static int pipe_open (serial_t scb, const char *name);
  39 static void pipe_close (serial_t scb);
  40
  41 extern void _initialize_ser_pipe (void);
  42
  43 struct pipe_state
  44   {
  45     int pid;
  46   };
  47
  48 /* Open up a raw pipe */
  49
  50 static int
  51 pipe_open (serial_t scb, const char *name)
  52 {
  53 #if !HAVE_SOCKETPAIR
  54   return -1;
  55 #else
  56   struct pipe_state *state;
  57   /* This chunk: */
  58   /* Copyright (c) 1988, 1993
  59    *      The Regents of the University of California.  All rights reserved.
  60    *
  61    * This code is derived from software written by Ken Arnold and
  62    * published in UNIX Review, Vol. 6, No. 8.
  63    */
  64   int pdes[2];
  65   int pid;
  66   if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
  67     return -1;
  68
  69   pid = vfork ();
  70
  71   /* Error. */
  72   if (pid == -1)
  73     {
  74       close (pdes[0]);
  75       close (pdes[1]);
  76       return -1;
  77     }
  78
  79   /* Child. */
  80   if (pid == 0)
  81     {
  82       /* re-wire pdes[1] to stdin/stdout */
  83       close (pdes[0]);
  84       if (pdes[1] != STDOUT_FILENO)
  85         {
  86           dup2 (pdes[1], STDOUT_FILENO);
  87           close (pdes[1]);
  88         }
  89       dup2 (STDOUT_FILENO, STDIN_FILENO);
  90 #if 0
  91       /* close any stray FD's - FIXME - how? */
  92       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
  93          from previous popen() calls that remain open in the
  94          parent process are closed in the new child process. */
  95       for (old = pidlist; old; old = old->next)
  96         close (fileno (old->fp));       /* don't allow a flush */
  97 #endif
  98       execl ("/bin/sh", "sh", "-c", name, NULL);
  99       _exit (127);
 100     }
 101
 102   /* Parent. */
 103   close (pdes[1]);
 104   /* :end chunk */
 105   state = XMALLOC (struct pipe_state);
 106   state->pid = pid;
 107   scb->fd = pdes[0];
 108   scb->state = state;
 109
 110   /* If we don't do this, GDB simply exits when the remote side dies.  */
 111   signal (SIGPIPE, SIG_IGN);
 112   return 0;
 113 #endif
 114 }
 115
 116 static void
 117 pipe_close (serial_t scb)
 118 {
 119   struct pipe_state *state = scb->state;
 120   if (state != NULL)
 121     {
 122       int pid = state->pid;
 123       close (scb->fd);
 124       scb->fd = -1;
 125       xfree (state);
 126       scb->state = NULL;
 127       kill (pid, SIGTERM);
 128       /* Might be useful to check that the child does die. */
 129     }
 130 }
 131
 132 static struct serial_ops pipe_ops;
 133
 134 void
 135 _initialize_ser_pipe (void)
 136 {
 137   struct serial_ops *ops = XMALLOC (struct serial_ops);
 138   memset (ops, sizeof (struct serial_ops), 0);
 139   ops->name = "pipe";
 140   ops->next = 0;
 141   ops->open = pipe_open;
 142   ops->close = pipe_close;
 143   ops->readchar = ser_unix_readchar;
 144   ops->write = ser_unix_write;
 145   ops->flush_output = ser_unix_nop_flush_output;
 146   ops->flush_input = ser_unix_flush_input;
 147   ops->send_break = ser_unix_nop_send_break;
 148   ops->go_raw = ser_unix_nop_raw;
 149   ops->get_tty_state = ser_unix_nop_get_tty_state;
 150   ops->set_tty_state = ser_unix_nop_set_tty_state;
 151   ops->print_tty_state = ser_unix_nop_print_tty_state;
 152   ops->noflush_set_tty_state = ser_unix_nop_noflush_set_tty_state;
 153   ops->setbaudrate = ser_unix_nop_setbaudrate;
 154   ops->setstopbits = ser_unix_nop_setstopbits;
 155   ops->drain_output = ser_unix_nop_drain_output;
 156   ops->async = ser_unix_async;
 157   serial_add_interface (ops);
 158 }