gdb/ser-pipe.c

   1 /* Serial interface for a pipe to a separate program
   2    Copyright (C) 1999-2001, 2007-2012 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
  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       /* We don't want ^c to kill the connection.  */
 102 #ifdef HAVE_SETSID
 103       pid_t sid = setsid ();
 104       if (sid == -1)
 105         signal (SIGINT, SIG_IGN);
 106 #else
 107       signal (SIGINT, SIG_IGN);
 108 #endif
 109
 110       /* Re-wire pdes[1] to stdin/stdout.  */
 111       close (pdes[0]);
 112       if (pdes[1] != STDOUT_FILENO)
 113         {
 114           dup2 (pdes[1], STDOUT_FILENO);
 115           close (pdes[1]);
 116         }
 117       dup2 (STDOUT_FILENO, STDIN_FILENO);
 118
 119       if (err_pdes[0] != -1)
 120         {
 121           close (err_pdes[0]);
 122           dup2 (err_pdes[1], STDERR_FILENO);
 123           close (err_pdes[1]);
 124         }
 125 #if 0
 126       /* close any stray FD's - FIXME - how?  */
 127       /* POSIX.2 B.3.2.2 "popen() shall ensure that any streams
 128          from previous popen() calls that remain open in the
 129          parent process are closed in the new child process.  */
 130       for (old = pidlist; old; old = old->next)
 131         close (fileno (old->fp));       /* Don't allow a flush.  */
 132 #endif
 133       execl ("/bin/sh", "sh", "-c", name, (char *) 0);
 134       _exit (127);
 135     }
 136
 137   /* Parent.  */
 138   close (pdes[1]);
 139   if (err_pdes[1] != -1)
 140     close (err_pdes[1]);
 141   /* :end chunk */
 142   state = XMALLOC (struct pipe_state);
 143   state->pid = pid;
 144   scb->fd = pdes[0];
 145   scb->error_fd = err_pdes[0];
 146   scb->state = state;
 147
 148   /* If we don't do this, GDB simply exits when the remote side dies.  */
 149   signal (SIGPIPE, SIG_IGN);
 150   return 0;
 151 #endif
 152 }
 153
 154 static void
 155 pipe_close (struct serial *scb)
 156 {
 157   struct pipe_state *state = scb->state;
 158
 159   close (scb->fd);
 160   scb->fd = -1;
 161
 162   if (state != NULL)
 163     {
 164       int wait_result, status;
 165
 166       /* Don't kill the task right away, give it a chance to shut down cleanly.
 167          But don't wait forever though.  */
 168 #define PIPE_CLOSE_TIMEOUT 5
 169
 170       /* Assume the program will exit after SIGTERM.  Might be
 171          useful to print any remaining stderr output from
 172          scb->error_fd while waiting.  */
 173 #define SIGTERM_TIMEOUT INT_MAX
 174
 175       wait_result = -1;
 176 #ifdef HAVE_WAITPID
 177       wait_result = wait_to_die_with_timeout (state->pid, &status,
 178                                               PIPE_CLOSE_TIMEOUT);
 179 #endif
 180       if (wait_result == -1)
 181         {
 182           kill (state->pid, SIGTERM);
 183 #ifdef HAVE_WAITPID
 184           wait_to_die_with_timeout (state->pid, &status, SIGTERM_TIMEOUT);
 185 #endif
 186         }
 187
 188       if (scb->error_fd != -1)
 189         close (scb->error_fd);
 190       scb->error_fd = -1;
 191       xfree (state);
 192       scb->state = NULL;
 193     }
 194 }
 195
 196 int
 197 gdb_pipe (int pdes[2])
 198 {
 199 #if !HAVE_SOCKETPAIR
 200   errno = ENOSYS;
 201   return -1;
 202 #else
 203
 204   if (socketpair (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
 205     return -1;
 206
 207   /* If we don't do this, GDB simply exits when the remote side
 208      dies.  */
 209   signal (SIGPIPE, SIG_IGN);
 210   return 0;
 211 #endif
 212 }
 213
 214 void
 215 _initialize_ser_pipe (void)
 216 {
 217   struct serial_ops *ops = XMALLOC (struct serial_ops);
 218
 219   memset (ops, 0, sizeof (struct serial_ops));
 220   ops->name = "pipe";
 221   ops->next = 0;
 222   ops->open = pipe_open;
 223   ops->close = pipe_close;
 224   ops->readchar = ser_base_readchar;
 225   ops->write = ser_base_write;
 226   ops->flush_output = ser_base_flush_output;
 227   ops->flush_input = ser_base_flush_input;
 228   ops->send_break = ser_base_send_break;
 229   ops->go_raw = ser_base_raw;
 230   ops->get_tty_state = ser_base_get_tty_state;
 231   ops->copy_tty_state = ser_base_copy_tty_state;
 232   ops->set_tty_state = ser_base_set_tty_state;
 233   ops->print_tty_state = ser_base_print_tty_state;
 234   ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;
 235   ops->setbaudrate = ser_base_setbaudrate;
 236   ops->setstopbits = ser_base_setstopbits;
 237   ops->drain_output = ser_base_drain_output;
 238   ops->async = ser_base_async;
 239   ops->read_prim = ser_unix_read_prim;
 240   ops->write_prim = ser_unix_write_prim;
 241   serial_add_interface (ops);
 242 }