llvm-project/lldb/source/Host/linux/LibcGlue.cpp

//===-- LibcGlue.cpp --------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// This file adds functions missing from libc on older versions of linux

#include <unistd.h>
#include <sys/syscall.h>
#include <lldb/Host/linux/Uio.h>
#include <cerrno>

#ifndef HAVE_PROCESS_VM_READV // If the syscall wrapper is not available, provide one.
ssize_t process_vm_readv(::pid_t pid,
			 const struct iovec *local_iov, unsigned long liovcnt,
			 const struct iovec *remote_iov, unsigned long riovcnt,
			 unsigned long flags)
{
#ifdef HAVE_NR_PROCESS_VM_READV // If we have the syscall number, we can issue the syscall ourselves.
    return syscall(__NR_process_vm_readv, pid, local_iov, liovcnt, remote_iov, riovcnt, flags);
#else // If not, let's pretend the syscall is not present.
    errno = ENOSYS;
    return -1;
#endif
}
#endif