1 //===-- Linux implementation of sigaltstack -------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "src/signal/sigaltstack.h" 10 #include "hdr/types/stack_t.h" 11 #include "src/__support/macros/config.h" 12 #include "src/errno/libc_errno.h" 13 #include "src/signal/linux/signal_utils.h" 14 15 #include "src/__support/common.h" 16 17 #include <sys/syscall.h> 18 19 namespace LIBC_NAMESPACE_DECL { 20 21 LLVM_LIBC_FUNCTION(int, sigaltstack, 22 (const stack_t *__restrict ss, stack_t *__restrict oss)) { 23 if (ss != nullptr) { 24 unsigned not_ss_disable = ~unsigned(SS_DISABLE); 25 if ((unsigned(ss->ss_flags) & not_ss_disable) != 0) { 26 // Flags cannot have anything other than SS_DISABLE set. 27 // We do the type-casting to unsigned because the |ss_flags| 28 // field of stack_t is of type "int". 29 libc_errno = EINVAL; 30 return -1; 31 } 32 if (ss->ss_size < MINSIGSTKSZ) { 33 libc_errno = ENOMEM; 34 return -1; 35 } 36 } 37 38 int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_sigaltstack, ss, oss); 39 if (ret < 0) { 40 libc_errno = -ret; 41 return -1; 42 } 43 return 0; 44 } 45 46 } // namespace LIBC_NAMESPACE_DECL 47