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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /hurd/alloc-fd.c
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initial import
Diffstat (limited to 'hurd/alloc-fd.c')
-rw-r--r--hurd/alloc-fd.c127
1 files changed, 127 insertions, 0 deletions
diff --git a/hurd/alloc-fd.c b/hurd/alloc-fd.c
new file mode 100644
index 0000000000..02a1bdfd52
--- /dev/null
+++ b/hurd/alloc-fd.c
@@ -0,0 +1,127 @@
+/* Copyright (C) 1994 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA. */
+
+#include <hurd.h>
+#include <hurd/fd.h>
+#include <hurd/resource.h>
+#include <stdlib.h>
+#include "hurdmalloc.h" /* XXX */
+
+/* Allocate a new file descriptor and return it, locked. The new
+ descriptor number will be no less than FIRST_FD. If the table is full,
+ set errno to EMFILE and return NULL. If FIRST_FD is negative or bigger
+ than the size of the table, set errno to EINVAL and return NULL. */
+
+struct hurd_fd *
+_hurd_alloc_fd (int *fd, int first_fd)
+{
+ int i;
+ void *crit;
+ long int rlimit;
+
+ if (first_fd < 0)
+ {
+ errno = EINVAL;
+ return NULL;
+ }
+
+ crit = _hurd_critical_section_lock ();
+
+ __mutex_lock (&_hurd_dtable_lock);
+
+ search:
+ for (i = first_fd; i < _hurd_dtablesize; ++i)
+ {
+ struct hurd_fd *d = _hurd_dtable[i];
+ if (d == NULL)
+ {
+ /* Allocate a new descriptor structure for this slot,
+ initializing its port cells to nil. The test below will catch
+ and return this descriptor cell after locking it. */
+ d = _hurd_new_fd (MACH_PORT_NULL, MACH_PORT_NULL);
+ if (d == NULL)
+ {
+ __mutex_unlock (&_hurd_dtable_lock);
+ _hurd_critical_section_unlock (crit);
+ return NULL;
+ }
+ _hurd_dtable[i] = d;
+ }
+
+ __spin_lock (&d->port.lock);
+ if (d->port.port == MACH_PORT_NULL)
+ {
+ __mutex_unlock (&_hurd_dtable_lock);
+ _hurd_critical_section_unlock (crit);
+ if (fd != NULL)
+ *fd = i;
+ return d;
+ }
+ else
+ __spin_unlock (&d->port.lock);
+ }
+
+ __mutex_lock (&_hurd_rlimit_lock);
+ rlimit = _hurd_rlimits[RLIMIT_OFILE].rlim_cur;
+ __mutex_unlock (&_hurd_rlimit_lock);
+
+ if (first_fd < rlimit)
+ {
+ /* The descriptor table is full. Check if we have reached the
+ resource limit, or only the allocated size. */
+ if (_hurd_dtablesize < rlimit)
+ {
+ /* Enlarge the table. */
+ int save = errno;
+ struct hurd_fd **new;
+ /* Try to double the table size (but don't exceed the limit).
+ If there isn't any at all, give it three slots (because
+ stdio will take that many anyway). */
+ int size = _hurd_dtablesize ? _hurd_dtablesize * 2 : 3;
+ if (size > rlimit)
+ size = rlimit;
+ /* If we fail to allocate that, decrement the desired size
+ until we succeed in allocating it. */
+ do
+ new = realloc (_hurd_dtable, size * sizeof (*_hurd_dtable));
+ while (new == NULL && size-- > _hurd_dtablesize);
+ if (new != NULL)
+ {
+ /* We managed to allocate a new table. Now install it. */
+ errno = save;
+ first_fd = _hurd_dtablesize;
+ /* Initialize the new slots. */
+ for (i = first_fd; i < size; ++i)
+ new[i] = NULL;
+ _hurd_dtablesize = size;
+ _hurd_dtable = new;
+ /* Go back to the loop to initialize the first new slot. */
+ goto search;
+ }
+ }
+ else
+ errno = EMFILE;
+ }
+ else
+ errno = EINVAL; /* Bogus FIRST_FD value. */
+
+ __mutex_unlock (&_hurd_dtable_lock);
+ _hurd_critical_section_unlock (crit);
+
+ return NULL;
+}