gdb/ser-pipe.c

   1 /* Serial interface for a pipe to a separate program
   2    Copyright (C) 1999-2015 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 "filestuff.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 (gdb_socketpair_cloexec (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
  67     return -1;
  68   if (gdb_socketpair_cloexec (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
 126       close_most_fds ();
 127       execl ("/bin/sh", "sh", "-c", name, (char *) 0);
 128       _exit (127);
 129     }
 130
 131   /* Parent.  */
 132   close (pdes[1]);
 133   if (err_pdes[1] != -1)
 134     close (err_pdes[1]);
 135   /* :end chunk */
 136   state = XNEW (struct pipe_state);
 137   state->pid = pid;
 138   scb->fd = pdes[0];
 139   scb->error_fd = err_pdes[0];
 140   scb->state = state;
 141
 142   /* If we don't do this, GDB simply exits when the remote side dies.  */
 143   signal (SIGPIPE, SIG_IGN);
 144   return 0;
 145 #endif
 146 }
 147
 148 static void
 149 pipe_close (struct serial *scb)
 150 {
 151   struct pipe_state *state = scb->state;
 152
 153   close (scb->fd);
 154   scb->fd = -1;
 155
 156   if (state != NULL)
 157     {
 158       int wait_result, status;
 159
 160       /* Don't kill the task right away, give it a chance to shut down cleanly.
 161          But don't wait forever though.  */
 162 #define PIPE_CLOSE_TIMEOUT 5
 163
 164       /* Assume the program will exit after SIGTERM.  Might be
 165          useful to print any remaining stderr output from
 166          scb->error_fd while waiting.  */
 167 #define SIGTERM_TIMEOUT INT_MAX
 168
 169       wait_result = -1;
 170 #ifdef HAVE_WAITPID
 171       wait_result = wait_to_die_with_timeout (state->pid, &status,
 172                                               PIPE_CLOSE_TIMEOUT);
 173 #endif
 174       if (wait_result == -1)
 175         {
 176           kill (state->pid, SIGTERM);
 177 #ifdef HAVE_WAITPID
 178           wait_to_die_with_timeout (state->pid, &status, SIGTERM_TIMEOUT);
 179 #endif
 180         }
 181
 182       if (scb->error_fd != -1)
 183         close (scb->error_fd);
 184       scb->error_fd = -1;
 185       xfree (state);
 186       scb->state = NULL;
 187     }
 188 }
 189
 190 int
 191 gdb_pipe (int pdes[2])
 192 {
 193 #if !HAVE_SOCKETPAIR
 194   errno = ENOSYS;
 195   return -1;
 196 #else
 197
 198   if (gdb_socketpair_cloexec (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
 199     return -1;
 200
 201   /* If we don't do this, GDB simply exits when the remote side
 202      dies.  */
 203   signal (SIGPIPE, SIG_IGN);
 204   return 0;
 205 #endif
 206 }
 207
 208 static const struct serial_ops pipe_ops =
 209 {
 210   "pipe",
 211   pipe_open,
 212   pipe_close,
 213   NULL,
 214   ser_base_readchar,
 215   ser_base_write,
 216   ser_base_flush_output,
 217   ser_base_flush_input,
 218   ser_base_send_break,
 219   ser_base_raw,
 220   ser_base_get_tty_state,
 221   ser_base_copy_tty_state,
 222   ser_base_set_tty_state,
 223   ser_base_print_tty_state,
 224   ser_base_noflush_set_tty_state,
 225   ser_base_setbaudrate,
 226   ser_base_setstopbits,
 227   ser_base_setparity,
 228   ser_base_drain_output,
 229   ser_base_async,
 230   ser_unix_read_prim,
 231   ser_unix_write_prim
 232 };
 233
 234 void
 235 _initialize_ser_pipe (void)
 236 {
 237   serial_add_interface (&pipe_ops);
 238 }