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/macros/sanitizer.h" // for MSAN_UNPOISON 14 #include "src/errno/libc_errno.h" 15 #include <sys/syscall.h> // For syscall numbers. 16 17 namespace LIBC_NAMESPACE { 18 19 LLVM_LIBC_FUNCTION(ssize_t, read, (int fd, void *buf, size_t count)) { 20 ssize_t ret = LIBC_NAMESPACE::syscall_impl<ssize_t>(SYS_read, fd, buf, count); 21 if (ret < 0) { 22 libc_errno = static_cast<int>(-ret); 23 return -1; 24 } 25 // The cast is important since there is a check that dereferences the pointer 26 // which fails on void*. 27 MSAN_UNPOISON(reinterpret_cast<char *>(buf), count); 28 return ret; 29 } 30 31 } // namespace LIBC_NAMESPACE 32