33 lines · cpp
1//===-- Linux implementation of read --------------------------------------===//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-exception6//7//===----------------------------------------------------------------------===//8 9#include "src/unistd/read.h"10 11#include "src/__support/OSUtil/syscall.h" // For internal syscall function.12#include "src/__support/common.h"13#include "src/__support/libc_errno.h"14#include "src/__support/macros/config.h"15#include "src/__support/macros/sanitizer.h" // for MSAN_UNPOISON16#include <sys/syscall.h> // For syscall numbers.17 18namespace LIBC_NAMESPACE_DECL {19 20LLVM_LIBC_FUNCTION(ssize_t, read, (int fd, void *buf, size_t count)) {21 ssize_t ret = LIBC_NAMESPACE::syscall_impl<ssize_t>(SYS_read, fd, buf, count);22 if (ret < 0) {23 libc_errno = static_cast<int>(-ret);24 return -1;25 }26 // The cast is important since there is a check that dereferences the pointer27 // which fails on void*.28 MSAN_UNPOISON(reinterpret_cast<char *>(buf), count);29 return ret;30}31 32} // namespace LIBC_NAMESPACE_DECL33