| 1 | //===-- Implementation of at-fork callback helpers -----------------------===// |
|---|---|
| 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 "fork_callbacks.h" |
| 10 | |
| 11 | #include "src/__support/threads/mutex.h" |
| 12 | |
| 13 | #include <stddef.h> // For size_t |
| 14 | |
| 15 | namespace LIBC_NAMESPACE { |
| 16 | |
| 17 | namespace { |
| 18 | |
| 19 | struct ForkCallbackTriple { |
| 20 | ForkCallback *prepare = nullptr; |
| 21 | ForkCallback *parent = nullptr; |
| 22 | ForkCallback *child = nullptr; |
| 23 | constexpr ForkCallbackTriple() = default; |
| 24 | }; |
| 25 | |
| 26 | class AtForkCallbackManager { |
| 27 | static constexpr size_t CALLBACK_SIZE = 32; |
| 28 | // TODO: Replace this with block store when integration tests |
| 29 | // can use allocators. |
| 30 | ForkCallbackTriple list[CALLBACK_SIZE]; |
| 31 | Mutex mtx; |
| 32 | size_t next_index; |
| 33 | |
| 34 | public: |
| 35 | constexpr AtForkCallbackManager() : mtx(false, false, false), next_index(0) {} |
| 36 | |
| 37 | bool register_triple(const ForkCallbackTriple &triple) { |
| 38 | MutexLock lock(&mtx); |
| 39 | if (next_index >= CALLBACK_SIZE) |
| 40 | return false; |
| 41 | list[next_index] = triple; |
| 42 | ++next_index; |
| 43 | return true; |
| 44 | } |
| 45 | |
| 46 | void invoke_prepare() { |
| 47 | MutexLock lock(&mtx); |
| 48 | for (size_t i = 0; i < next_index; ++i) { |
| 49 | auto prepare = list[i].prepare; |
| 50 | if (prepare) |
| 51 | prepare(); |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | void invoke_parent() { |
| 56 | MutexLock lock(&mtx); |
| 57 | for (size_t i = 0; i < next_index; ++i) { |
| 58 | auto parent = list[i].parent; |
| 59 | if (parent) |
| 60 | parent(); |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | void invoke_child() { |
| 65 | MutexLock lock(&mtx); |
| 66 | for (size_t i = 0; i < next_index; ++i) { |
| 67 | auto child = list[i].child; |
| 68 | if (child) |
| 69 | child(); |
| 70 | } |
| 71 | } |
| 72 | }; |
| 73 | |
| 74 | AtForkCallbackManager cb_manager; |
| 75 | |
| 76 | } // Anonymous namespace |
| 77 | |
| 78 | bool register_atfork_callbacks(ForkCallback *prepare_cb, |
| 79 | ForkCallback *parent_cb, |
| 80 | ForkCallback *child_cb) { |
| 81 | return cb_manager.register_triple(triple: {.prepare: prepare_cb, .parent: parent_cb, .child: child_cb}); |
| 82 | } |
| 83 | |
| 84 | void invoke_child_callbacks() { cb_manager.invoke_child(); } |
| 85 | |
| 86 | void invoke_prepare_callbacks() { cb_manager.invoke_prepare(); } |
| 87 | |
| 88 | void invoke_parent_callbacks() { cb_manager.invoke_parent(); } |
| 89 | |
| 90 | } // namespace LIBC_NAMESPACE |
| 91 |