1 | /* Emulate sigstack function using sigaltstack. |
2 | Copyright (C) 1998-2016 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998. |
5 | |
6 | The GNU C Library is free software; you can redistribute it and/or |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either |
9 | version 2.1 of the License, or (at your option) any later version. |
10 | |
11 | The GNU C Library is distributed in the hope that it will be useful, |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
14 | Lesser General Public License for more details. |
15 | |
16 | You should have received a copy of the GNU Lesser General Public |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ |
19 | |
20 | #include <signal.h> |
21 | #include <stddef.h> |
22 | #include <sys/syscall.h> |
23 | |
24 | |
25 | #ifdef __NR_sigaltstack |
26 | int |
27 | sigstack (struct sigstack *ss, struct sigstack *oss) |
28 | { |
29 | stack_t sas; |
30 | stack_t *sasp = NULL; |
31 | stack_t osas; |
32 | stack_t *osasp = oss == NULL ? NULL : &osas; |
33 | int result; |
34 | |
35 | if (ss != NULL) |
36 | { |
37 | /* We have to convert the information. */ |
38 | sas.ss_sp = ss->ss_sp; |
39 | sas.ss_flags = ss->ss_onstack ? SS_ONSTACK : 0; |
40 | |
41 | /* For the size of the stack we have no value we can pass to the |
42 | kernel. This is why this function should not be used. We simply |
43 | assume that all the memory down to address zero (in case the stack |
44 | grows down) is available. */ |
45 | sas.ss_size = ss->ss_sp - NULL; |
46 | |
47 | sasp = &sas; |
48 | } |
49 | |
50 | /* Call the kernel. */ |
51 | result = __sigaltstack (sasp, osasp); |
52 | |
53 | /* Convert the result, if wanted and possible. */ |
54 | if (result == 0 && oss != NULL) |
55 | { |
56 | oss->ss_sp = osas.ss_sp; |
57 | oss->ss_onstack = (osas.ss_flags & SS_ONSTACK) != 0; |
58 | } |
59 | |
60 | return result; |
61 | } |
62 | |
63 | link_warning (sigstack, "the `sigstack' function is dangerous. `sigaltstack' should be used instead." ) |
64 | #else |
65 | # include <signal/sigstack.c> |
66 | #endif |
67 | |