gdb/ser-pipe.c

   1 /* Serial interface for a pipe to a separate program
   2    Copyright (C) 1999, 2000, 2001, 2007 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 err_pdes[2];
  66   int pid;
  67   if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
  68     return -1;
  69   if (socketpair (AF_UNIX, SOCK_STREAM, 0, err_pdes) < 0)
  70     return -1;
  71
  72   /* Create the child process to run the command in.  Note that the
  73      apparent call to vfork() below *might* actually be a call to
  74      fork() due to the fact that autoconf will ``#define vfork fork''
  75      on certain platforms.  */
  76   pid = vfork ();
  77
  78   /* Error. */
  79   if (pid == -1)
  80     {
  81       close (pdes[0]);
  82       close (pdes[1]);
  83       close (err_pdes[0]);
  84       close (err_pdes[1]);
  85       return -1;
  86     }
  87
  88   if (fcntl (err_pdes[0], F_SETFL, O_NONBLOCK) == -1)
  89     {
  90       close (err_pdes[0]);
  91       close (err_pdes[1]);
  92       err_pdes[0] = err_pdes[1] = -1;
  93     }
  94
  95   /* Child. */
  96   if (pid == 0)
  97     {
  98       /* re-wire pdes[1] to stdin/stdout */
  99       close (pdes[0]);
 100       if (pdes[1] != STDOUT_FILENO)
 101         {
 102           dup2 (pdes[1], STDOUT_FILENO);
 103           close (pdes[1]);
 104         }
 105       dup2 (STDOUT_FILENO, STDIN_FILENO);
 106
 107       if (err_pdes[0] != -1)
 108         {
 109           close (err_pdes[0]);
 110           dup2 (err_pdes[1], STDERR_FILENO);
 111           close (err_pdes[1]);
 112         }
 113 #if 0
 114       /* close any stray FD's - FIXME - how? */
 115       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
 116          from previous popen() calls that remain open in the
 117          parent process are closed in the new child process. */
 118       for (old = pidlist; old; old = old->next)
 119         close (fileno (old->fp));       /* don't allow a flush */
 120 #endif
 121       execl ("/bin/sh", "sh", "-c", name, (char *) 0);
 122       _exit (127);
 123     }
 124
 125   /* Parent. */
 126   close (pdes[1]);
 127   /* :end chunk */
 128   state = XMALLOC (struct pipe_state);
 129   state->pid = pid;
 130   scb->fd = pdes[0];
 131   scb->error_fd = err_pdes[0];
 132   scb->state = state;
 133
 134   /* If we don't do this, GDB simply exits when the remote side dies.  */
 135   signal (SIGPIPE, SIG_IGN);
 136   return 0;
 137 #endif
 138 }
 139
 140 static void
 141 pipe_close (struct serial *scb)
 142 {
 143   struct pipe_state *state = scb->state;
 144   if (state != NULL)
 145     {
 146       int pid = state->pid;
 147       close (scb->fd);
 148       scb->fd = -1;
 149       xfree (state);
 150       scb->state = NULL;
 151       kill (pid, SIGTERM);
 152       /* Might be useful to check that the child does die. */
 153     }
 154 }
 155
 156 static struct serial_ops pipe_ops;
 157
 158 void
 159 _initialize_ser_pipe (void)
 160 {
 161   struct serial_ops *ops = XMALLOC (struct serial_ops);
 162   memset (ops, 0, sizeof (struct serial_ops));
 163   ops->name = "pipe";
 164   ops->next = 0;
 165   ops->open = pipe_open;
 166   ops->close = pipe_close;
 167   ops->readchar = ser_base_readchar;
 168   ops->write = ser_base_write;
 169   ops->flush_output = ser_base_flush_output;
 170   ops->flush_input = ser_base_flush_input;
 171   ops->send_break = ser_base_send_break;
 172   ops->go_raw = ser_base_raw;
 173   ops->get_tty_state = ser_base_get_tty_state;
 174   ops->set_tty_state = ser_base_set_tty_state;
 175   ops->print_tty_state = ser_base_print_tty_state;
 176   ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;
 177   ops->setbaudrate = ser_base_setbaudrate;
 178   ops->setstopbits = ser_base_setstopbits;
 179   ops->drain_output = ser_base_drain_output;
 180   ops->async = ser_base_async;
 181   ops->read_prim = ser_unix_read_prim;
 182   ops->write_prim = ser_unix_write_prim;
 183   serial_add_interface (ops);
 184 }