diff options
Diffstat (limited to 'src/lib/talloc.c')
| -rw-r--r-- | src/lib/talloc.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/src/lib/talloc.c b/src/lib/talloc.c new file mode 100644 index 0000000..a2af16a --- /dev/null +++ b/src/lib/talloc.c @@ -0,0 +1,74 @@ +/* + * This 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. + * + * This 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 this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA + */ + +/** Functions which we wish were included in the standard talloc distribution + * + * @file src/lib/talloc.c + * + * @copyright 2017 The FreeRADIUS server project + * @copyright 2017 Arran Cudbard-Bell (a.cudbardb@freeradius.org) + */ +RCSID("$Id$") + +#include <freeradius-devel/math.h> +#include <freeradius-devel/libradius.h> +#include <freeradius-devel/talloc.h> + +/** Return a page aligned talloc memory array + * + * Because we can't intercept talloc's malloc() calls, we need to do some tricks + * in order to get the first allocation in the array page aligned, and to limit + * the size of the array to a multiple of the page size. + * + * The reason for wanting a page aligned talloc array, is it allows us to + * mprotect() the pages that belong to the array. + * + * Talloc chunks appear to be allocated within the protected region, so this should + * catch frees too. + * + * @param[in] ctx to allocate array memory in. + * @param[out] start The first aligned address in the array. + * @param[in] alignment What alignment the memory chunk should have. + * @param[in] size How big to make the array. Will be corrected to a multiple + * of the page size. The actual array size will be size + * rounded to a multiple of the (page_size), + page_size + * @return + * - A talloc chunk on success. + * - NULL on failure. + */ +TALLOC_CTX *talloc_aligned_array(TALLOC_CTX *ctx, void **start, size_t alignment, size_t size) +{ + size_t rounded; + size_t array_size; + void *next; + TALLOC_CTX *array; + + rounded = ROUND_UP(size, alignment); /* Round up to a multiple of the page size */ + if (rounded == 0) rounded = alignment; + + array_size = rounded + alignment; + array = talloc_array(ctx, uint8_t, array_size); /* Over allocate */ + if (!array) { + fr_strerror_printf("Out of memory"); + return NULL; + } + + next = (void *)ROUND_UP((uintptr_t)array, alignment); /* Round up address to the next multiple */ + *start = next; + + return array; +} + |