gdb/ser-pipe.c

   1 /* Serial interface for a pipe to a separate program
   2    Copyright (C) 1999, 2000, 2001, 2007, 2008 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 3 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, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "serial.h"
  23 #include "ser-base.h"
  24 #include "ser-unix.h"
  25
  26 #include "gdb_vfork.h"
  27
  28 #include <sys/types.h>
  29 #include <sys/socket.h>
  30 #include <sys/time.h>
  31 #include <fcntl.h>
  32 #include "gdb_string.h"
  33
  34 #include <signal.h>
  35
  36 static int pipe_open (struct serial *scb, const char *name);
  37 static void pipe_close (struct serial *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 (struct serial *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 err_pdes[2];
  64   int pid;
  65   if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
  66     return -1;
  67   if (socketpair (AF_UNIX, SOCK_STREAM, 0, err_pdes) < 0)
  68     return -1;
  69
  70   /* Create the child process to run the command in.  Note that the
  71      apparent call to vfork() below *might* actually be a call to
  72      fork() due to the fact that autoconf will ``#define vfork fork''
  73      on certain platforms.  */
  74   pid = vfork ();
  75
  76   /* Error. */
  77   if (pid == -1)
  78     {
  79       close (pdes[0]);
  80       close (pdes[1]);
  81       close (err_pdes[0]);
  82       close (err_pdes[1]);
  83       return -1;
  84     }
  85
  86   if (fcntl (err_pdes[0], F_SETFL, O_NONBLOCK) == -1)
  87     {
  88       close (err_pdes[0]);
  89       close (err_pdes[1]);
  90       err_pdes[0] = err_pdes[1] = -1;
  91     }
  92
  93   /* Child. */
  94   if (pid == 0)
  95     {
  96       /* re-wire pdes[1] to stdin/stdout */
  97       close (pdes[0]);
  98       if (pdes[1] != STDOUT_FILENO)
  99         {
 100           dup2 (pdes[1], STDOUT_FILENO);
 101           close (pdes[1]);
 102         }
 103       dup2 (STDOUT_FILENO, STDIN_FILENO);
 104
 105       if (err_pdes[0] != -1)
 106         {
 107           close (err_pdes[0]);
 108           dup2 (err_pdes[1], STDERR_FILENO);
 109           close (err_pdes[1]);
 110         }
 111 #if 0
 112       /* close any stray FD's - FIXME - how? */
 113       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
 114          from previous popen() calls that remain open in the
 115          parent process are closed in the new child process. */
 116       for (old = pidlist; old; old = old->next)
 117         close (fileno (old->fp));       /* don't allow a flush */
 118 #endif
 119       execl ("/bin/sh", "sh", "-c", name, (char *) 0);
 120       _exit (127);
 121     }
 122
 123   /* Parent. */
 124   close (pdes[1]);
 125   /* :end chunk */
 126   state = XMALLOC (struct pipe_state);
 127   state->pid = pid;
 128   scb->fd = pdes[0];
 129   scb->error_fd = err_pdes[0];
 130   scb->state = state;
 131
 132   /* If we don't do this, GDB simply exits when the remote side dies.  */
 133   signal (SIGPIPE, SIG_IGN);
 134   return 0;
 135 #endif
 136 }
 137
 138 static void
 139 pipe_close (struct serial *scb)
 140 {
 141   struct pipe_state *state = scb->state;
 142   if (state != NULL)
 143     {
 144       int pid = state->pid;
 145       close (scb->fd);
 146       scb->fd = -1;
 147       xfree (state);
 148       scb->state = NULL;
 149       kill (pid, SIGTERM);
 150       /* Might be useful to check that the child does die. */
 151     }
 152 }
 153
 154 static struct serial_ops pipe_ops;
 155
 156 void
 157 _initialize_ser_pipe (void)
 158 {
 159   struct serial_ops *ops = XMALLOC (struct serial_ops);
 160   memset (ops, 0, sizeof (struct serial_ops));
 161   ops->name = "pipe";
 162   ops->next = 0;
 163   ops->open = pipe_open;
 164   ops->close = pipe_close;
 165   ops->readchar = ser_base_readchar;
 166   ops->write = ser_base_write;
 167   ops->flush_output = ser_base_flush_output;
 168   ops->flush_input = ser_base_flush_input;
 169   ops->send_break = ser_base_send_break;
 170   ops->go_raw = ser_base_raw;
 171   ops->get_tty_state = ser_base_get_tty_state;
 172   ops->set_tty_state = ser_base_set_tty_state;
 173   ops->print_tty_state = ser_base_print_tty_state;
 174   ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;
 175   ops->setbaudrate = ser_base_setbaudrate;
 176   ops->setstopbits = ser_base_setstopbits;
 177   ops->drain_output = ser_base_drain_output;
 178   ops->async = ser_base_async;
 179   ops->read_prim = ser_unix_read_prim;
 180   ops->write_prim = ser_unix_write_prim;
 181   serial_add_interface (ops);
 182 }