gdb/ser-pipe.c

   1 /* Serial interface for a pipe to a separate program
   2    Copyright (C) 1999, 2000, 2001, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4
   5    Contributed by Cygnus Solutions.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "serial.h"
  24 #include "ser-base.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 err_pdes[2];
  65   int pid;
  66   if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
  67     return -1;
  68   if (socketpair (AF_UNIX, SOCK_STREAM, 0, err_pdes) < 0)
  69     {
  70       close (pdes[0]);
  71       close (pdes[1]);
  72       return -1;
  73     }
  74
  75   /* Create the child process to run the command in.  Note that the
  76      apparent call to vfork() below *might* actually be a call to
  77      fork() due to the fact that autoconf will ``#define vfork fork''
  78      on certain platforms.  */
  79   pid = vfork ();
  80
  81   /* Error. */
  82   if (pid == -1)
  83     {
  84       close (pdes[0]);
  85       close (pdes[1]);
  86       close (err_pdes[0]);
  87       close (err_pdes[1]);
  88       return -1;
  89     }
  90
  91   if (fcntl (err_pdes[0], F_SETFL, O_NONBLOCK) == -1)
  92     {
  93       close (err_pdes[0]);
  94       close (err_pdes[1]);
  95       err_pdes[0] = err_pdes[1] = -1;
  96     }
  97
  98   /* Child. */
  99   if (pid == 0)
 100     {
 101       /* re-wire pdes[1] to stdin/stdout */
 102       close (pdes[0]);
 103       if (pdes[1] != STDOUT_FILENO)
 104         {
 105           dup2 (pdes[1], STDOUT_FILENO);
 106           close (pdes[1]);
 107         }
 108       dup2 (STDOUT_FILENO, STDIN_FILENO);
 109
 110       if (err_pdes[0] != -1)
 111         {
 112           close (err_pdes[0]);
 113           dup2 (err_pdes[1], STDERR_FILENO);
 114           close (err_pdes[1]);
 115         }
 116 #if 0
 117       /* close any stray FD's - FIXME - how? */
 118       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
 119          from previous popen() calls that remain open in the
 120          parent process are closed in the new child process. */
 121       for (old = pidlist; old; old = old->next)
 122         close (fileno (old->fp));       /* don't allow a flush */
 123 #endif
 124       execl ("/bin/sh", "sh", "-c", name, (char *) 0);
 125       _exit (127);
 126     }
 127
 128   /* Parent. */
 129   close (pdes[1]);
 130   if (err_pdes[1] != -1)
 131     close (err_pdes[1]);
 132   /* :end chunk */
 133   state = XMALLOC (struct pipe_state);
 134   state->pid = pid;
 135   scb->fd = pdes[0];
 136   scb->error_fd = err_pdes[0];
 137   scb->state = state;
 138
 139   /* If we don't do this, GDB simply exits when the remote side dies.  */
 140   signal (SIGPIPE, SIG_IGN);
 141   return 0;
 142 #endif
 143 }
 144
 145 static void
 146 pipe_close (struct serial *scb)
 147 {
 148   struct pipe_state *state = scb->state;
 149   if (state != NULL)
 150     {
 151       int pid = state->pid;
 152       close (scb->fd);
 153       scb->fd = -1;
 154       if (scb->error_fd != -1)
 155         close (scb->error_fd);
 156       scb->error_fd = -1;
 157       xfree (state);
 158       scb->state = NULL;
 159       kill (pid, SIGTERM);
 160       /* Might be useful to check that the child does die,
 161          and while we're waiting for it to die print any remaining
 162          stderr output.  */
 163     }
 164 }
 165
 166 void
 167 _initialize_ser_pipe (void)
 168 {
 169   struct serial_ops *ops = XMALLOC (struct serial_ops);
 170   memset (ops, 0, sizeof (struct serial_ops));
 171   ops->name = "pipe";
 172   ops->next = 0;
 173   ops->open = pipe_open;
 174   ops->close = pipe_close;
 175   ops->readchar = ser_base_readchar;
 176   ops->write = ser_base_write;
 177   ops->flush_output = ser_base_flush_output;
 178   ops->flush_input = ser_base_flush_input;
 179   ops->send_break = ser_base_send_break;
 180   ops->go_raw = ser_base_raw;
 181   ops->get_tty_state = ser_base_get_tty_state;
 182   ops->set_tty_state = ser_base_set_tty_state;
 183   ops->print_tty_state = ser_base_print_tty_state;
 184   ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;
 185   ops->setbaudrate = ser_base_setbaudrate;
 186   ops->setstopbits = ser_base_setstopbits;
 187   ops->drain_output = ser_base_drain_output;
 188   ops->async = ser_base_async;
 189   ops->read_prim = ser_unix_read_prim;
 190   ops->write_prim = ser_unix_write_prim;
 191   serial_add_interface (ops);
 192 }