xref: /aosp_15_r20/external/llvm-libc/src/signal/linux/sigaltstack.cpp (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1*71db0c75SAndroid Build Coastguard Worker //===-- Linux implementation of sigaltstack -------------------------------===//
2*71db0c75SAndroid Build Coastguard Worker //
3*71db0c75SAndroid Build Coastguard Worker // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*71db0c75SAndroid Build Coastguard Worker // See https://llvm.org/LICENSE.txt for license information.
5*71db0c75SAndroid Build Coastguard Worker // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*71db0c75SAndroid Build Coastguard Worker //
7*71db0c75SAndroid Build Coastguard Worker //===----------------------------------------------------------------------===//
8*71db0c75SAndroid Build Coastguard Worker 
9*71db0c75SAndroid Build Coastguard Worker #include "src/signal/sigaltstack.h"
10*71db0c75SAndroid Build Coastguard Worker #include "hdr/types/stack_t.h"
11*71db0c75SAndroid Build Coastguard Worker #include "src/__support/macros/config.h"
12*71db0c75SAndroid Build Coastguard Worker #include "src/errno/libc_errno.h"
13*71db0c75SAndroid Build Coastguard Worker #include "src/signal/linux/signal_utils.h"
14*71db0c75SAndroid Build Coastguard Worker 
15*71db0c75SAndroid Build Coastguard Worker #include "src/__support/common.h"
16*71db0c75SAndroid Build Coastguard Worker 
17*71db0c75SAndroid Build Coastguard Worker #include <sys/syscall.h>
18*71db0c75SAndroid Build Coastguard Worker 
19*71db0c75SAndroid Build Coastguard Worker namespace LIBC_NAMESPACE_DECL {
20*71db0c75SAndroid Build Coastguard Worker 
21*71db0c75SAndroid Build Coastguard Worker LLVM_LIBC_FUNCTION(int, sigaltstack,
22*71db0c75SAndroid Build Coastguard Worker                    (const stack_t *__restrict ss, stack_t *__restrict oss)) {
23*71db0c75SAndroid Build Coastguard Worker   if (ss != nullptr) {
24*71db0c75SAndroid Build Coastguard Worker     unsigned not_ss_disable = ~unsigned(SS_DISABLE);
25*71db0c75SAndroid Build Coastguard Worker     if ((unsigned(ss->ss_flags) & not_ss_disable) != 0) {
26*71db0c75SAndroid Build Coastguard Worker       // Flags cannot have anything other than SS_DISABLE set.
27*71db0c75SAndroid Build Coastguard Worker       // We do the type-casting to unsigned because the |ss_flags|
28*71db0c75SAndroid Build Coastguard Worker       // field of stack_t is of type "int".
29*71db0c75SAndroid Build Coastguard Worker       libc_errno = EINVAL;
30*71db0c75SAndroid Build Coastguard Worker       return -1;
31*71db0c75SAndroid Build Coastguard Worker     }
32*71db0c75SAndroid Build Coastguard Worker     if (ss->ss_size < MINSIGSTKSZ) {
33*71db0c75SAndroid Build Coastguard Worker       libc_errno = ENOMEM;
34*71db0c75SAndroid Build Coastguard Worker       return -1;
35*71db0c75SAndroid Build Coastguard Worker     }
36*71db0c75SAndroid Build Coastguard Worker   }
37*71db0c75SAndroid Build Coastguard Worker 
38*71db0c75SAndroid Build Coastguard Worker   int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_sigaltstack, ss, oss);
39*71db0c75SAndroid Build Coastguard Worker   if (ret < 0) {
40*71db0c75SAndroid Build Coastguard Worker     libc_errno = -ret;
41*71db0c75SAndroid Build Coastguard Worker     return -1;
42*71db0c75SAndroid Build Coastguard Worker   }
43*71db0c75SAndroid Build Coastguard Worker   return 0;
44*71db0c75SAndroid Build Coastguard Worker }
45*71db0c75SAndroid Build Coastguard Worker 
46*71db0c75SAndroid Build Coastguard Worker } // namespace LIBC_NAMESPACE_DECL
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