| 1 | /* Variable-sized buffer with on-stack default allocation. |
| 2 | Copyright (C) 2015-2020 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 3 of the License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public |
| 16 | License along with the GNU C Library; if not, see |
| 17 | <https://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | #ifndef _LIBC |
| 20 | # include <libc-config.h> |
| 21 | #endif |
| 22 | |
| 23 | #include <scratch_buffer.h> |
| 24 | #include <errno.h> |
| 25 | #include <limits.h> |
| 26 | |
| 27 | bool |
| 28 | __libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer, |
| 29 | size_t nelem, size_t size) |
| 30 | { |
| 31 | size_t new_length = nelem * size; |
| 32 | |
| 33 | /* Avoid overflow check if both values are small. */ |
| 34 | if ((nelem | size) >> (sizeof (size_t) * CHAR_BIT / 2) != 0 |
| 35 | && nelem != 0 && size != new_length / nelem) |
| 36 | { |
| 37 | /* Overflow. Discard the old buffer, but it must remain valid |
| 38 | to free. */ |
| 39 | scratch_buffer_free (buffer); |
| 40 | scratch_buffer_init (buffer); |
| 41 | __set_errno (ENOMEM); |
| 42 | return false; |
| 43 | } |
| 44 | |
| 45 | if (new_length <= buffer->length) |
| 46 | return true; |
| 47 | |
| 48 | /* Discard old buffer. */ |
| 49 | scratch_buffer_free (buffer); |
| 50 | |
| 51 | char *new_ptr = malloc (new_length); |
| 52 | if (new_ptr == NULL) |
| 53 | { |
| 54 | /* Buffer must remain valid to free. */ |
| 55 | scratch_buffer_init (buffer); |
| 56 | return false; |
| 57 | } |
| 58 | |
| 59 | /* Install new heap-based buffer. */ |
| 60 | buffer->data = new_ptr; |
| 61 | buffer->length = new_length; |
| 62 | return true; |
| 63 | } |
| 64 | libc_hidden_def (__libc_scratch_buffer_set_array_size) |