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-exception 6 // 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 17 namespace LIBC_NAMESPACE_DECL { 18 19 LLVM_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_DECL 46