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