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fbbc9a4e | 1 | /* sigaltstack wrappers. |
6d7e8eda | 2 | Copyright (C) 2019-2023 Free Software Foundation, Inc. |
fbbc9a4e ZW |
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 Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 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 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
fbbc9a4e ZW |
18 | |
19 | #include <support/xsignal.h> | |
20 | #include <support/support.h> | |
21 | #include <support/xunistd.h> | |
22 | #include <support/check.h> | |
23 | ||
24 | #include <stdlib.h> | |
25 | #include <string.h> | |
26 | #include <sys/mman.h> | |
27 | #include <sys/param.h> /* roundup, MAX */ | |
28 | ||
3367acdb AZ |
29 | #ifndef MAP_NORESERVE |
30 | # define MAP_NORESERVE 0 | |
31 | #endif | |
32 | #ifndef MAP_STACK | |
33 | # define MAP_STACK 0 | |
34 | #endif | |
35 | ||
fbbc9a4e ZW |
36 | /* The "cookie" returned by xalloc_sigstack points to one of these |
37 | structures. */ | |
38 | struct sigstack_desc | |
39 | { | |
ae8c243d | 40 | struct support_stack stack; |
fbbc9a4e ZW |
41 | stack_t alt_stack; /* The address and size of the stack itself. */ |
42 | stack_t old_stack; /* The previous signal stack. */ | |
43 | }; | |
44 | ||
45 | void * | |
46 | xalloc_sigstack (size_t size) | |
47 | { | |
fbbc9a4e | 48 | struct sigstack_desc *desc = xmalloc (sizeof (struct sigstack_desc)); |
ae8c243d AZ |
49 | desc->stack = support_stack_alloc (size); |
50 | desc->alt_stack.ss_sp = desc->stack.stack; | |
fbbc9a4e | 51 | desc->alt_stack.ss_flags = 0; |
ae8c243d | 52 | desc->alt_stack.ss_size = desc->stack.size; |
fbbc9a4e ZW |
53 | |
54 | if (sigaltstack (&desc->alt_stack, &desc->old_stack)) | |
55 | FAIL_EXIT1 ("sigaltstack (new stack: sp=%p, size=%zu, flags=%u): %m\n", | |
56 | desc->alt_stack.ss_sp, desc->alt_stack.ss_size, | |
57 | desc->alt_stack.ss_flags); | |
58 | ||
59 | return desc; | |
60 | } | |
61 | ||
62 | void | |
63 | xfree_sigstack (void *stack) | |
64 | { | |
65 | struct sigstack_desc *desc = stack; | |
66 | ||
67 | if (sigaltstack (&desc->old_stack, 0)) | |
68 | FAIL_EXIT1 ("sigaltstack (restore old stack: sp=%p, size=%zu, flags=%u): " | |
69 | "%m\n", desc->old_stack.ss_sp, desc->old_stack.ss_size, | |
70 | desc->old_stack.ss_flags); | |
ae8c243d | 71 | support_stack_free (&desc->stack); |
fbbc9a4e ZW |
72 | free (desc); |
73 | } | |
74 | ||
75 | void | |
76 | xget_sigstack_location (const void *stack, unsigned char **addrp, size_t *sizep) | |
77 | { | |
78 | const struct sigstack_desc *desc = stack; | |
79 | *addrp = desc->alt_stack.ss_sp; | |
80 | *sizep = desc->alt_stack.ss_size; | |
81 | } |