libc/src/signal/linux/sigaction.cpp

   1 //===-- Linux implementation of sigaction ---------------------------------===//
   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/sigaction.h"
  10 #include "src/errno/libc_errno.h"
  11 #include "src/signal/linux/signal_utils.h"
  12
  13 #include "src/__support/common.h"
  14
  15 #include <signal.h>
  16
  17 namespace __llvm_libc {
  18
  19 // TOOD: Some architectures will have their signal trampoline functions in the
  20 // vdso, use those when available.
  21
  22 extern "C" void __restore_rt();
  23
  24 LLVM_LIBC_FUNCTION(int, sigaction,
  25                    (int signal, const struct sigaction *__restrict libc_new,
  26                     struct sigaction *__restrict libc_old)) {
  27   KernelSigaction kernel_new;
  28   if (libc_new) {
  29     kernel_new = *libc_new;
  30     if (!(kernel_new.sa_flags & SA_RESTORER)) {
  31       kernel_new.sa_flags |= SA_RESTORER;
  32       kernel_new.sa_restorer = __restore_rt;
  33     }
  34   }
  35
  36   KernelSigaction kernel_old;
  37   int ret = __llvm_libc::syscall_impl(
  38       SYS_rt_sigaction, signal, libc_new ? &kernel_new : nullptr,
  39       libc_old ? &kernel_old : nullptr, sizeof(sigset_t));
  40   if (ret) {
  41     libc_errno = -ret;
  42     return -1;
  43   }
  44
  45   if (libc_old)
  46     *libc_old = kernel_old;
  47   return 0;
  48 }
  49
  50 } // namespace __llvm_libc