| 1 | //===---------- Shared implementations for shm_open/shm_unlink ------------===// |
|---|---|
| 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/__support/CPP/array.h" |
| 10 | #include "src/__support/CPP/optional.h" |
| 11 | #include "src/__support/CPP/string_view.h" |
| 12 | #include "src/errno/libc_errno.h" |
| 13 | #include "src/string/memory_utils/inline_memcpy.h" |
| 14 | |
| 15 | // TODO: Get PATH_MAX via https://github.com/llvm/llvm-project/issues/85121 |
| 16 | #include <linux/limits.h> |
| 17 | |
| 18 | namespace LIBC_NAMESPACE { |
| 19 | |
| 20 | namespace shm_common { |
| 21 | |
| 22 | LIBC_INLINE_VAR constexpr cpp::string_view SHM_PREFIX = "/dev/shm/"; |
| 23 | using SHMPath = cpp::array<char, NAME_MAX + SHM_PREFIX.size() + 1>; |
| 24 | |
| 25 | LIBC_INLINE cpp::optional<SHMPath> translate_name(cpp::string_view name) { |
| 26 | // trim leading slashes |
| 27 | size_t offset = name.find_first_not_of(c: '/'); |
| 28 | if (offset == cpp::string_view::npos) { |
| 29 | libc_errno = EINVAL; |
| 30 | return cpp::nullopt; |
| 31 | } |
| 32 | name = name.substr(Start: offset); |
| 33 | |
| 34 | // check the name |
| 35 | if (name.size() > NAME_MAX) { |
| 36 | libc_errno = ENAMETOOLONG; |
| 37 | return cpp::nullopt; |
| 38 | } |
| 39 | if (name == "."|| name == ".."|| name.contains(c: '/')) { |
| 40 | libc_errno = EINVAL; |
| 41 | return cpp::nullopt; |
| 42 | } |
| 43 | |
| 44 | // prepend the prefix |
| 45 | SHMPath buffer; |
| 46 | inline_memcpy(dst: buffer.data(), src: SHM_PREFIX.data(), count: SHM_PREFIX.size()); |
| 47 | inline_memcpy(dst: buffer.data() + SHM_PREFIX.size(), src: name.data(), count: name.size()); |
| 48 | buffer[SHM_PREFIX.size() + name.size()] = '\0'; |
| 49 | return buffer; |
| 50 | } |
| 51 | } // namespace shm_common |
| 52 | |
| 53 | } // namespace LIBC_NAMESPACE |
| 54 |