46 lines · cpp
1//===-- Implementation of getenv ------------------------------------------===//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/stdlib/getenv.h"10#include "config/app.h"11#include "src/__support/CPP/string_view.h"12#include "src/__support/common.h"13#include "src/__support/macros/config.h"14 15#include <stddef.h> // For size_t.16 17namespace LIBC_NAMESPACE_DECL {18 19LLVM_LIBC_FUNCTION(char *, getenv, (const char *name)) {20 char **env_ptr = reinterpret_cast<char **>(LIBC_NAMESPACE::app.env_ptr);21 22 if (name == nullptr || env_ptr == nullptr)23 return nullptr;24 25 LIBC_NAMESPACE::cpp::string_view env_var_name(name);26 if (env_var_name.size() == 0)27 return nullptr;28 for (char **env = env_ptr; *env != nullptr; env++) {29 LIBC_NAMESPACE::cpp::string_view cur(*env);30 if (!cur.starts_with(env_var_name))31 continue;32 33 if (cur[env_var_name.size()] != '=')34 continue;35 36 // Remove the name and the equals sign.37 cur.remove_prefix(env_var_name.size() + 1);38 // We know that data is null terminated, so this is safe.39 return const_cast<char *>(cur.data());40 }41 42 return nullptr;43}44 45} // namespace LIBC_NAMESPACE_DECL46