hurd/dtable.c

   1 /* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <hurd.h>
  21 #include <hurd/term.h>
  22 #include <hurd/fd.h>
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25 #include <fcntl.h>
  26 #include <limits.h>
  27 #include <cthreads.h>           /* For `struct mutex'.  */
  28 #include "set-hooks.h"
  29 #include "hurdmalloc.h"         /* XXX */
  30
  31
  32 struct mutex _hurd_dtable_lock = MUTEX_INITIALIZER; /* XXX ld bug; must init */
  33 struct hurd_fd **_hurd_dtable;
  34 int _hurd_dtablesize;
  35
  36
  37 DEFINE_HOOK (_hurd_fd_subinit, (void));
  38
  39 /* Initialize the file descriptor table at startup.  */
  40
  41 static void
  42 init_dtable (void)
  43 {
  44   int i;
  45
  46   __mutex_init (&_hurd_dtable_lock);
  47
  48   /* The initial size of the descriptor table is that of the passed-in
  49      table.  It will be expanded as necessary up to _hurd_dtable_rlimit.  */
  50   _hurd_dtablesize = _hurd_init_dtablesize;
  51
  52   /* Allocate the vector of pointers.  */
  53   _hurd_dtable = malloc (_hurd_dtablesize * sizeof (*_hurd_dtable));
  54   if (_hurd_dtablesize != 0 && _hurd_dtable == NULL)
  55     __libc_fatal ("hurd: Can't allocate file descriptor table\n");
  56
  57   /* Initialize the descriptor table.  */
  58   for (i = 0; (unsigned int) i < _hurd_init_dtablesize; ++i)
  59     {
  60       if (_hurd_init_dtable[i] == MACH_PORT_NULL)
  61         /* An unused descriptor is marked by a null pointer.  */
  62         _hurd_dtable[i] = NULL;
  63       else
  64         {
  65           /* Allocate a new file descriptor structure.  */
  66           struct hurd_fd *new = malloc (sizeof (struct hurd_fd));
  67           if (new == NULL)
  68             __libc_fatal ("hurd: Can't allocate initial file descriptors\n");
  69
  70           /* Initialize the port cells.  */
  71           _hurd_port_init (&new->port, MACH_PORT_NULL);
  72           _hurd_port_init (&new->ctty, MACH_PORT_NULL);
  73
  74           /* Install the port in the descriptor.
  75              This sets up all the ctty magic.  */
  76           _hurd_port2fd (new, _hurd_init_dtable[i], 0);
  77
  78           _hurd_dtable[i] = new;
  79         }
  80     }
  81
  82   /* Clear out the initial descriptor table.
  83      Everything must use _hurd_dtable now.  */
  84   __vm_deallocate (__mach_task_self (),
  85                    (vm_address_t) _hurd_init_dtable,
  86                    _hurd_init_dtablesize * sizeof (_hurd_init_dtable[0]));
  87   _hurd_init_dtable = NULL;
  88   _hurd_init_dtablesize = 0;
  89
  90   /* Initialize the remaining empty slots in the table.  */
  91   for (; i < _hurd_dtablesize; ++i)
  92     _hurd_dtable[i] = NULL;
  93
  94   /* Run things that want to run after the file descriptor table
  95      is initialized.  */
  96   RUN_HOOK (_hurd_fd_subinit, ());
  97
  98   (void) &init_dtable;          /* Avoid "defined but not used" warning.  */
  99 }
 100
 101 text_set_element (_hurd_subinit, init_dtable);
 102
 103 /* XXX when the linker supports it, the following functions should all be
 104    elsewhere and just have text_set_elements here.  */
 105 \f
 106 /* Called by `getdport' to do its work.  */
 107
 108 static file_t
 109 get_dtable_port (int fd)
 110 {
 111   file_t dport;
 112   int err = HURD_DPORT_USE (fd, __mach_port_mod_refs (__mach_task_self (),
 113                                                       (dport = port),
 114                                                       MACH_PORT_RIGHT_SEND,
 115                                                       1));
 116   if (err)
 117     {
 118       errno = err;
 119       return MACH_PORT_NULL;
 120     }
 121   else
 122     return dport;
 123 }
 124
 125 file_t (*_hurd_getdport_fn) (int fd) = get_dtable_port;
 126 \f
 127 #include <hurd/signal.h>
 128
 129 /* We are in the child fork; the dtable lock is still held.
 130    The parent has inserted send rights for all the normal io ports,
 131    but we must recover ctty-special ports for ourselves.  */
 132 static error_t
 133 fork_child_dtable (void)
 134 {
 135   error_t err;
 136   int i;
 137
 138   err = 0;
 139
 140   for (i = 0; !err && i < _hurd_dtablesize; ++i)
 141     {
 142       struct hurd_fd *d = _hurd_dtable[i];
 143       if (d == NULL)
 144         continue;
 145
 146       /* No other thread is using the send rights in the child task.  */
 147       d->port.users = d->ctty.users = NULL;
 148
 149       if (d->ctty.port != MACH_PORT_NULL)
 150         {
 151           /* There was a ctty-special port in the parent.
 152              We need to get one for ourselves too.  */
 153           __mach_port_deallocate (__mach_task_self (), d->ctty.port);
 154           err = __term_open_ctty (d->port.port, _hurd_pid, _hurd_pgrp,
 155                                   &d->ctty.port);
 156           if (err)
 157             d->ctty.port = MACH_PORT_NULL;
 158         }
 159
 160       /* XXX for each fd with a cntlmap, reauth and re-map_cntl.  */
 161     }
 162   return err;
 163
 164   (void) &fork_child_dtable;    /* Avoid "defined but not used" warning.  */
 165 }
 166
 167 data_set_element (_hurd_fork_locks, _hurd_dtable_lock); /* XXX ld bug: bss */
 168 text_set_element (_hurd_fork_child_hook, fork_child_dtable);
 169 \f
 170 /* Called when our process group has changed.  */
 171
 172 static void
 173 ctty_new_pgrp (void)
 174 {
 175   int i;
 176
 177   HURD_CRITICAL_BEGIN;
 178   __mutex_lock (&_hurd_dtable_lock);
 179
 180   for (i = 0; i < _hurd_dtablesize; ++i)
 181     {
 182       struct hurd_fd *const d = _hurd_dtable[i];
 183       struct hurd_userlink ulink, ctty_ulink;
 184       io_t port, ctty;
 185
 186       if (d == NULL)
 187         /* Nothing to do for an unused descriptor cell.  */
 188         continue;
 189
 190       port = _hurd_port_get (&d->port, &ulink);
 191       ctty = _hurd_port_get (&d->ctty, &ctty_ulink);
 192
 193       if (ctty != MACH_PORT_NULL)
 194         {
 195           /* This fd has a ctty-special port.  We need a new one, to tell
 196              the io server of our different process group.  */
 197           io_t new;
 198           if (__term_open_ctty (port, _hurd_pid, _hurd_pgrp, &new))
 199             new = MACH_PORT_NULL;
 200           _hurd_port_set (&d->ctty, new);
 201         }
 202
 203       _hurd_port_free (&d->port, &ulink, port);
 204       _hurd_port_free (&d->ctty, &ctty_ulink, ctty);
 205     }
 206
 207   __mutex_unlock (&_hurd_dtable_lock);
 208   HURD_CRITICAL_END;
 209
 210   (void) &ctty_new_pgrp;        /* Avoid "defined but not used" warning.  */
 211 }
 212
 213 text_set_element (_hurd_pgrp_changed_hook, ctty_new_pgrp);
 214 \f
 215 /* Called to reauthenticate the dtable when the auth port changes.  */
 216
 217 static void
 218 reauth_dtable (void)
 219 {
 220   int i;
 221
 222   HURD_CRITICAL_BEGIN;
 223   __mutex_lock (&_hurd_dtable_lock);
 224
 225   for (i = 0; i < _hurd_dtablesize; ++i)
 226     {
 227       struct hurd_fd *const d = _hurd_dtable[i];
 228       mach_port_t new, newctty, ref;
 229
 230       if (d == NULL)
 231         /* Nothing to do for an unused descriptor cell.  */
 232         continue;
 233
 234       ref = __mach_reply_port ();
 235
 236       /* Take the descriptor cell's lock.  */
 237       __spin_lock (&d->port.lock);
 238
 239       /* Reauthenticate the descriptor's port.  */
 240       if (d->port.port != MACH_PORT_NULL &&
 241           ! __io_reauthenticate (d->port.port,
 242                                  ref, MACH_MSG_TYPE_MAKE_SEND) &&
 243           ! __USEPORT (AUTH, __auth_user_authenticate
 244                        (port,
 245                         d->port.port,
 246                         ref, MACH_MSG_TYPE_MAKE_SEND,
 247                         &new)))
 248         {
 249           /* Replace the port in the descriptor cell
 250              with the newly reauthenticated port.  */
 251
 252           if (d->ctty.port != MACH_PORT_NULL &&
 253               ! __io_reauthenticate (d->ctty.port,
 254                                      ref, MACH_MSG_TYPE_MAKE_SEND) &&
 255               ! __USEPORT (AUTH, __auth_user_authenticate
 256                            (port,
 257                             d->ctty.port,
 258                             ref, MACH_MSG_TYPE_MAKE_SEND,
 259                             &newctty)))
 260             _hurd_port_set (&d->ctty, newctty);
 261
 262           _hurd_port_locked_set (&d->port, new);
 263         }
 264       else
 265         /* Lost.  Leave this descriptor cell alone.  */
 266         __spin_unlock (&d->port.lock);
 267
 268       __mach_port_destroy (__mach_task_self (), ref);
 269     }
 270
 271   __mutex_unlock (&_hurd_dtable_lock);
 272   HURD_CRITICAL_END;
 273
 274   (void) &reauth_dtable;        /* Avoid "defined but not used" warning.  */
 275 }
 276
 277 text_set_element (_hurd_reauth_hook, reauth_dtable);