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
  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     {
  71       close (pdes[0]);
  72       close (pdes[1]);
  73       return -1;
  74     }
  75
  76   /* Create the child process to run the command in.  Note that the
  77      apparent call to vfork() below *might* actually be a call to
  78      fork() due to the fact that autoconf will ``#define vfork fork''
  79      on certain platforms.  */
  80   pid = vfork ();
  81
  82   /* Error. */
  83   if (pid == -1)
  84     {
  85       close (pdes[0]);
  86       close (pdes[1]);
  87       close (err_pdes[0]);
  88       close (err_pdes[1]);
  89       return -1;
  90     }
  91
  92   if (fcntl (err_pdes[0], F_SETFL, O_NONBLOCK) == -1)
  93     {
  94       close (err_pdes[0]);
  95       close (err_pdes[1]);
  96       err_pdes[0] = err_pdes[1] = -1;
  97     }
  98
  99   /* Child. */
 100   if (pid == 0)
 101     {
 102       /* We don't want ^c to kill the connection.  */
 103 #ifdef HAVE_SETSID
 104       pid_t sid = setsid ();
 105       if (sid == -1)
 106         signal (SIGINT, SIG_IGN);
 107 #else
 108       signal (SIGINT, SIG_IGN);
 109 #endif
 110
 111       /* re-wire pdes[1] to stdin/stdout */
 112       close (pdes[0]);
 113       if (pdes[1] != STDOUT_FILENO)
 114         {
 115           dup2 (pdes[1], STDOUT_FILENO);
 116           close (pdes[1]);
 117         }
 118       dup2 (STDOUT_FILENO, STDIN_FILENO);
 119
 120       if (err_pdes[0] != -1)
 121         {
 122           close (err_pdes[0]);
 123           dup2 (err_pdes[1], STDERR_FILENO);
 124           close (err_pdes[1]);
 125         }
 126 #if 0
 127       /* close any stray FD's - FIXME - how? */
 128       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
 129          from previous popen() calls that remain open in the
 130          parent process are closed in the new child process. */
 131       for (old = pidlist; old; old = old->next)
 132         close (fileno (old->fp));       /* don't allow a flush */
 133 #endif
 134       execl ("/bin/sh", "sh", "-c", name, (char *) 0);
 135       _exit (127);
 136     }
 137
 138   /* Parent. */
 139   close (pdes[1]);
 140   if (err_pdes[1] != -1)
 141     close (err_pdes[1]);
 142   /* :end chunk */
 143   state = XMALLOC (struct pipe_state);
 144   state->pid = pid;
 145   scb->fd = pdes[0];
 146   scb->error_fd = err_pdes[0];
 147   scb->state = state;
 148
 149   /* If we don't do this, GDB simply exits when the remote side dies.  */
 150   signal (SIGPIPE, SIG_IGN);
 151   return 0;
 152 #endif
 153 }
 154
 155 static void
 156 pipe_close (struct serial *scb)
 157 {
 158   struct pipe_state *state = scb->state;
 159
 160   if (state != NULL)
 161     {
 162       int pid = state->pid;
 163       close (scb->fd);
 164       scb->fd = -1;
 165       if (scb->error_fd != -1)
 166         close (scb->error_fd);
 167       scb->error_fd = -1;
 168       xfree (state);
 169       scb->state = NULL;
 170       kill (pid, SIGTERM);
 171       /* Might be useful to check that the child does die,
 172          and while we're waiting for it to die print any remaining
 173          stderr output.  */
 174     }
 175 }
 176
 177 void
 178 _initialize_ser_pipe (void)
 179 {
 180   struct serial_ops *ops = XMALLOC (struct serial_ops);
 181
 182   memset (ops, 0, sizeof (struct serial_ops));
 183   ops->name = "pipe";
 184   ops->next = 0;
 185   ops->open = pipe_open;
 186   ops->close = pipe_close;
 187   ops->readchar = ser_base_readchar;
 188   ops->write = ser_base_write;
 189   ops->flush_output = ser_base_flush_output;
 190   ops->flush_input = ser_base_flush_input;
 191   ops->send_break = ser_base_send_break;
 192   ops->go_raw = ser_base_raw;
 193   ops->get_tty_state = ser_base_get_tty_state;
 194   ops->set_tty_state = ser_base_set_tty_state;
 195   ops->print_tty_state = ser_base_print_tty_state;
 196   ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;
 197   ops->setbaudrate = ser_base_setbaudrate;
 198   ops->setstopbits = ser_base_setstopbits;
 199   ops->drain_output = ser_base_drain_output;
 200   ops->async = ser_base_async;
 201   ops->read_prim = ser_unix_read_prim;
 202   ops->write_prim = ser_unix_write_prim;
 203   serial_add_interface (ops);
 204 }