54 lines · cpp
1//===-- Linux implementation of gethostname -------------------------------===//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/gethostname.h"10 11#include "hdr/types/size_t.h"12#include "src/__support/OSUtil/syscall.h" // For internal syscall function.13#include "src/__support/common.h"14#include "src/__support/libc_errno.h"15#include "src/__support/macros/config.h"16#include "src/string/string_utils.h"17 18#include <sys/syscall.h> // For syscall numbers.19#include <sys/utsname.h>20 21namespace LIBC_NAMESPACE_DECL {22 23LLVM_LIBC_FUNCTION(int, gethostname, (char *name, size_t size)) {24 // Check for invalid pointer25 if (name == nullptr) {26 libc_errno = EFAULT;27 return -1;28 }29 30 // Because there is no SYS_gethostname syscall, we use uname to get the31 // hostname.32 utsname unameData;33 int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_uname, &unameData);34 if (ret < 0) {35 libc_errno = static_cast<int>(-ret);36 return -1;37 }38 39 // Guarantee that the name will be null terminated.40 // The amount of bytes copied is min(size + 1, strlen(nodename) + 1)41 // +1 to account for the null terminator (the last copied byte is a NULL).42 internal::strlcpy(name, unameData.nodename, size + 1);43 44 // Checks if the length of the hostname was greater than or equal to size45 if (internal::string_length(unameData.nodename) >= size) {46 libc_errno = ENAMETOOLONG;47 return -1;48 }49 50 return 0;51}52 53} // namespace LIBC_NAMESPACE_DECL54