gdb/ser-pipe.c

   1 /* Serial interface for a pipe to a separate program
   2    Copyright (C) 1999-2013 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 #include "filestuff.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 (gdb_socketpair_cloexec (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
  68     return -1;
  69   if (gdb_socketpair_cloexec (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
 127       close_most_fds ();
 128       execl ("/bin/sh", "sh", "-c", name, (char *) 0);
 129       _exit (127);
 130     }
 131
 132   /* Parent.  */
 133   close (pdes[1]);
 134   if (err_pdes[1] != -1)
 135     close (err_pdes[1]);
 136   /* :end chunk */
 137   state = XMALLOC (struct pipe_state);
 138   state->pid = pid;
 139   scb->fd = pdes[0];
 140   scb->error_fd = err_pdes[0];
 141   scb->state = state;
 142
 143   /* If we don't do this, GDB simply exits when the remote side dies.  */
 144   signal (SIGPIPE, SIG_IGN);
 145   return 0;
 146 #endif
 147 }
 148
 149 static void
 150 pipe_close (struct serial *scb)
 151 {
 152   struct pipe_state *state = scb->state;
 153
 154   close (scb->fd);
 155   scb->fd = -1;
 156
 157   if (state != NULL)
 158     {
 159       int wait_result, status;
 160
 161       /* Don't kill the task right away, give it a chance to shut down cleanly.
 162          But don't wait forever though.  */
 163 #define PIPE_CLOSE_TIMEOUT 5
 164
 165       /* Assume the program will exit after SIGTERM.  Might be
 166          useful to print any remaining stderr output from
 167          scb->error_fd while waiting.  */
 168 #define SIGTERM_TIMEOUT INT_MAX
 169
 170       wait_result = -1;
 171 #ifdef HAVE_WAITPID
 172       wait_result = wait_to_die_with_timeout (state->pid, &status,
 173                                               PIPE_CLOSE_TIMEOUT);
 174 #endif
 175       if (wait_result == -1)
 176         {
 177           kill (state->pid, SIGTERM);
 178 #ifdef HAVE_WAITPID
 179           wait_to_die_with_timeout (state->pid, &status, SIGTERM_TIMEOUT);
 180 #endif
 181         }
 182
 183       if (scb->error_fd != -1)
 184         close (scb->error_fd);
 185       scb->error_fd = -1;
 186       xfree (state);
 187       scb->state = NULL;
 188     }
 189 }
 190
 191 int
 192 gdb_pipe (int pdes[2])
 193 {
 194 #if !HAVE_SOCKETPAIR
 195   errno = ENOSYS;
 196   return -1;
 197 #else
 198
 199   if (gdb_socketpair_cloexec (AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
 200     return -1;
 201
 202   /* If we don't do this, GDB simply exits when the remote side
 203      dies.  */
 204   signal (SIGPIPE, SIG_IGN);
 205   return 0;
 206 #endif
 207 }
 208
 209 void
 210 _initialize_ser_pipe (void)
 211 {
 212   struct serial_ops *ops = XMALLOC (struct serial_ops);
 213
 214   memset (ops, 0, sizeof (struct serial_ops));
 215   ops->name = "pipe";
 216   ops->next = 0;
 217   ops->open = pipe_open;
 218   ops->close = pipe_close;
 219   ops->readchar = ser_base_readchar;
 220   ops->write = ser_base_write;
 221   ops->flush_output = ser_base_flush_output;
 222   ops->flush_input = ser_base_flush_input;
 223   ops->send_break = ser_base_send_break;
 224   ops->go_raw = ser_base_raw;
 225   ops->get_tty_state = ser_base_get_tty_state;
 226   ops->copy_tty_state = ser_base_copy_tty_state;
 227   ops->set_tty_state = ser_base_set_tty_state;
 228   ops->print_tty_state = ser_base_print_tty_state;
 229   ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;
 230   ops->setbaudrate = ser_base_setbaudrate;
 231   ops->setstopbits = ser_base_setstopbits;
 232   ops->drain_output = ser_base_drain_output;
 233   ops->async = ser_base_async;
 234   ops->read_prim = ser_unix_read_prim;
 235   ops->write_prim = ser_unix_write_prim;
 236   serial_add_interface (ops);
 237 }