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-exception
6//
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_UNPOISON
16#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 pointer
27 // which fails on void*.
28 MSAN_UNPOISON(reinterpret_cast<char *>(buf), count);
29 return ret;
30}
31
32} // namespace LIBC_NAMESPACE_DECL
33

source code of libc/src/unistd/linux/read.cpp