gnu/dist/gdb6/gdb/ser-pipe.c

   1 /* Serial interface for a pipe to a separate program
   2    Copyright (C) 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., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, USA.  */
  22
  23 #include "defs.h"
  24 #include "serial.h"
  25 #include "ser-base.h"
  26 #include "ser-unix.h"
  27
  28 #include "gdb_vfork.h"
  29
  30 #include <sys/types.h>
  31 #include <sys/socket.h>
  32 #include <sys/time.h>
  33 #include <fcntl.h>
  34 #include "gdb_string.h"
  35
  36 #include <signal.h>
  37
  38 static int pipe_open (struct serial *scb, const char *name);
  39 static void pipe_close (struct serial *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 (struct serial *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   /* Create the child process to run the command in.  Note that the
  70      apparent call to vfork() below *might* actually be a call to
  71      fork() due to the fact that autoconf will ``#define vfork fork''
  72      on certain platforms.  */
  73   pid = vfork ();
  74
  75   /* Error. */
  76   if (pid == -1)
  77     {
  78       close (pdes[0]);
  79       close (pdes[1]);
  80       return -1;
  81     }
  82
  83   /* Child. */
  84   if (pid == 0)
  85     {
  86       /* re-wire pdes[1] to stdin/stdout */
  87       close (pdes[0]);
  88       if (pdes[1] != STDOUT_FILENO)
  89         {
  90           dup2 (pdes[1], STDOUT_FILENO);
  91           close (pdes[1]);
  92         }
  93       dup2 (STDOUT_FILENO, STDIN_FILENO);
  94 #if 0
  95       /* close any stray FD's - FIXME - how? */
  96       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
  97          from previous popen() calls that remain open in the
  98          parent process are closed in the new child process. */
  99       for (old = pidlist; old; old = old->next)
 100         close (fileno (old->fp));       /* don't allow a flush */
 101 #endif
 102       execl ("/bin/sh", "sh", "-c", name, (char *) 0);
 103       _exit (127);
 104     }
 105
 106   /* Parent. */
 107   close (pdes[1]);
 108   /* :end chunk */
 109   state = XMALLOC (struct pipe_state);
 110   state->pid = pid;
 111   scb->fd = pdes[0];
 112   scb->state = state;
 113
 114   /* If we don't do this, GDB simply exits when the remote side dies.  */
 115   signal (SIGPIPE, SIG_IGN);
 116   return 0;
 117 #endif
 118 }
 119
 120 static void
 121 pipe_close (struct serial *scb)
 122 {
 123   struct pipe_state *state = scb->state;
 124   if (state != NULL)
 125     {
 126       int pid = state->pid;
 127       close (scb->fd);
 128       scb->fd = -1;
 129       xfree (state);
 130       scb->state = NULL;
 131       kill (pid, SIGTERM);
 132       /* Might be useful to check that the child does die. */
 133     }
 134 }
 135
 136 static struct serial_ops pipe_ops;
 137
 138 void
 139 _initialize_ser_pipe (void)
 140 {
 141   struct serial_ops *ops = XMALLOC (struct serial_ops);
 142   memset (ops, 0, sizeof (struct serial_ops));
 143   ops->name = "pipe";
 144   ops->next = 0;
 145   ops->open = pipe_open;
 146   ops->close = pipe_close;
 147   ops->readchar = ser_base_readchar;
 148   ops->write = ser_base_write;
 149   ops->flush_output = ser_base_flush_output;
 150   ops->flush_input = ser_base_flush_input;
 151   ops->send_break = ser_base_send_break;
 152   ops->go_raw = ser_base_raw;
 153   ops->get_tty_state = ser_base_get_tty_state;
 154   ops->set_tty_state = ser_base_set_tty_state;
 155   ops->print_tty_state = ser_base_print_tty_state;
 156   ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;
 157   ops->setbaudrate = ser_base_setbaudrate;
 158   ops->setstopbits = ser_base_setstopbits;
 159   ops->drain_output = ser_base_drain_output;
 160   ops->async = ser_base_async;
 161   ops->read_prim = ser_unix_read_prim;
 162   ops->write_prim = ser_unix_write_prim;
 163   serial_add_interface (ops);
 164 }