gdb/ser-pipe.c

   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
  37 static int pipe_open (struct serial *scb, const char *name);
  38 static void pipe_close (struct serial *scb);
  39
  40 extern void _initialize_ser_pipe (void);
  41
  42 struct pipe_state
  43   {
  44     int pid;
  45   };
  46
  47 /* Open up a raw pipe */
  48
  49 static int
  50 pipe_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, NULL);
 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
 119 static void
 120 pipe_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
 135 static struct serial_ops pipe_ops;
 136
 137 void
 138 _initialize_ser_pipe (void)
 139 {
 140   struct serial_ops *ops = XMALLOC (struct serial_ops);
 141   memset (ops, sizeof (struct serial_ops), 0);
 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 }