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/* Copyright (C) 1994-2020 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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#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,
and make sure it exceeds FIRST_FD. */
int size = _hurd_dtablesize * 2;
if (size > rlimit)
size = rlimit;
else if (size <= first_fd)
size = first_fd + 1;
if (size * sizeof (*_hurd_dtable) < size)
{
/* Integer overflow! */
errno = ENOMEM;
goto out;
}
/* 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-- > first_fd);
if (new != NULL)
{
/* We managed to allocate a new table. Now install it. */
errno = save;
if (first_fd < _hurd_dtablesize)
first_fd = _hurd_dtablesize;
/* Initialize the new slots. */
for (i = _hurd_dtablesize; 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 = ENOMEM;
}
else
errno = EMFILE;
}
else
errno = EINVAL; /* Bogus FIRST_FD value. */
out:
__mutex_unlock (&_hurd_dtable_lock);
_hurd_critical_section_unlock (crit);
return NULL;
}
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