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/__support/macros/config.h"
  15 #include "src/errno/libc_errno.h"
  16 #include <stdarg.h>
  17
  18 namespace LIBC_NAMESPACE_DECL {
  19
  20 LLVM_LIBC_FUNCTION(long, __llvm_libc_syscall,
  21                    (long number, long arg1, long arg2, long arg3, long arg4,
  22                     long arg5, long arg6)) {
  23   long ret = LIBC_NAMESPACE::syscall_impl<long>(number, arg1, arg2, arg3, arg4,
  24                                                 arg5, arg6);
  25   // Syscalls may return large positive values that overflow, but will never
  26   // return values between -4096 and -1
  27   if (static_cast<unsigned long>(ret) > -4096UL) {
  28     libc_errno = static_cast<int>(-ret);
  29     return -1;
  30   }
  31   return ret;
  32 }
  33
  34 } // namespace LIBC_NAMESPACE_DECL