1: /* Copyright (C) 1994, 1995, 1996, 1997 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 Lesser General Public
    6:    License as published by the Free Software Foundation; either
    7:    version 2.1 of the 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:    Lesser General Public License for more details.
   13: 
   14:    You should have received a copy of the GNU Lesser General Public
   15:    License along with the GNU C Library; if not, write to the Free
   16:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   17:    02111-1307 USA.  */
   18: 
   19: #include <hurd.h>
   20: #include <hurd/fd.h>
   21: #include <hurd/resource.h>
   22: #include <stdlib.h>
   23: #include "hurdmalloc.h"         /* XXX */
   24: 
   25: /* Allocate a new file descriptor and return it, locked.  The new
   26:    descriptor number will be no less than FIRST_FD.  If the table is full,
   27:    set errno to EMFILE and return NULL.  If FIRST_FD is negative or bigger
   28:    than the size of the table, set errno to EINVAL and return NULL.  */
   29: 
   30: struct hurd_fd *
   31: _hurd_alloc_fd (int *fd, int first_fd)
   32: {
   33:   int i;
   34:   void *crit;
   35:   long int rlimit;
   36: 
   37:   if (first_fd < 0)
   38:     {
   39:       errno = EINVAL;
   40:       return NULL;
   41:     }
   42: 
   43:   crit = _hurd_critical_section_lock ();
   44: 
   45:   __mutex_lock (&_hurd_dtable_lock);
   46: 
   47:  search:
   48:   for (i = first_fd; i < _hurd_dtablesize; ++i)
   49:     {
   50:       struct hurd_fd *d = _hurd_dtable[i];
   51:       if (d == NULL)
   52:         {
   53:           /* Allocate a new descriptor structure for this slot,
   54:              initializing its port cells to nil.  The test below will catch
   55:              and return this descriptor cell after locking it.  */
   56:           d = _hurd_new_fd (MACH_PORT_NULL, MACH_PORT_NULL);
   57:           if (d == NULL)
   58:             {
   59:               __mutex_unlock (&_hurd_dtable_lock);
   60:               _hurd_critical_section_unlock (crit);
   61:               return NULL;
   62:             }
   63:           _hurd_dtable[i] = d;
   64:         }
   65: 
   66:       __spin_lock (&d->port.lock);
   67:       if (d->port.port == MACH_PORT_NULL)
   68:         {
   69:           __mutex_unlock (&_hurd_dtable_lock);
   70:           _hurd_critical_section_unlock (crit);
   71:           if (fd != NULL)
   72:             *fd = i;
   73:           return d;
   74:         }
   75:       else
   76:         __spin_unlock (&d->port.lock);
   77:     }
   78: 
   79:   __mutex_lock (&_hurd_rlimit_lock);
   80:   rlimit = _hurd_rlimits[RLIMIT_OFILE].rlim_cur;
   81:   __mutex_unlock (&_hurd_rlimit_lock);
   82: 
   83:   if (first_fd < rlimit)
   84:     {
   85:       /* The descriptor table is full.  Check if we have reached the
   86:          resource limit, or only the allocated size.  */
   87:       if (_hurd_dtablesize < rlimit)
   88:         {
   89:           /* Enlarge the table.  */
   90:           int save = errno;
   91:           struct hurd_fd **new;
   92:           /* Try to double the table size, but don't exceed the limit,
   93:              and make sure it exceeds FIRST_FD.  */
   94:           int size = _hurd_dtablesize * 2;
   95:           if (size > rlimit)
   96:             size = rlimit;
   97:           else if (size <= first_fd)
   98:             size = first_fd + 1;
   99: 
  100:           if (size * sizeof (*_hurd_dtable) < size)
  101:             {
  102:               /* Integer overflow! */
  103:               errno = ENOMEM;
  104:               goto out;
  105:             }
  106: 
  107:           /* If we fail to allocate that, decrement the desired size
  108:              until we succeed in allocating it.  */
  109:           do
  110:             new = realloc (_hurd_dtable, size * sizeof (*_hurd_dtable));
  111:           while (new == NULL && size-- > first_fd);
  112: 
  113:           if (new != NULL)
  114:             {
  115:               /* We managed to allocate a new table.  Now install it.  */
  116:               errno = save;
  117:               if (first_fd < _hurd_dtablesize)
  118:                 first_fd = _hurd_dtablesize;
  119:               /* Initialize the new slots.  */
  120:               for (i = _hurd_dtablesize; i < size; ++i)
  121:                 new[i] = NULL;
  122:               _hurd_dtablesize = size;
  123:               _hurd_dtable = new;
  124:               /* Go back to the loop to initialize the first new slot.  */
  125:               goto search;
  126:             }
  127:           else
  128:             errno = ENOMEM;
  129:         }
  130:       else
  131:         errno = EMFILE;
  132:     }
  133:   else
  134:     errno = EINVAL;             /* Bogus FIRST_FD value.  */
  135: 
  136:  out:
  137:   __mutex_unlock (&_hurd_dtable_lock);
  138:   _hurd_critical_section_unlock (crit);
  139: 
  140:   return NULL;
  141: }