libc/src/unistd/linux/syscall.cpp

   1 //===-- Linux implementation of syscall -----------------------------------===//
   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/unistd/syscall.h"
  10
  11 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
  12 #include "src/__support/common.h"
  13
  14 #include "src/errno/libc_errno.h"
  15 #include <stdarg.h>
  16
  17 namespace __llvm_libc {
  18
  19 LLVM_LIBC_FUNCTION(long, __llvm_libc_syscall,
  20                    (long number, long arg1, long arg2, long arg3, long arg4,
  21                     long arg5, long arg6)) {
  22   long ret =
  23       __llvm_libc::syscall_impl(number, arg1, arg2, arg3, arg4, arg5, arg6);
  24   // Syscalls may return large positive values that overflow, but will never
  25   // return values between -4096 and -1
  26   if (static_cast<unsigned long>(ret) > -4096UL) {
  27     libc_errno = -ret;
  28     return -1;
  29   }
  30   return ret;
  31 }
  32
  33 } // namespace __llvm_libc