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/config.h" 14 #include "src/__support/macros/sanitizer.h" // for MSAN_UNPOISON 15 #include "src/errno/libc_errno.h" 16 #include <sys/syscall.h> // For syscall numbers. 17 18 namespace LIBC_NAMESPACE_DECL { 19 20 LLVM_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