On Wed, 5 Jun 2024 20:08:10 GMT, Robert Toyonaga <d...@openjdk.org> wrote:
> ### Summary > This change ensures we don't get undefined behavior when > calling[`isspace`](https://pubs.opengroup.org/onlinepubs/007904975/functions/isspace.html). > `isspace` accepts an `int` argument that "the application shall ensure is a > character representable as an unsigned char or equal to the value of the > macro EOF.". > > Previously, there was no checking of the values passed to `isspace`. I've > replaced direct calls with a new wrapper `os::is_space` that performs a range > check and prevents the possibility of undefined behavior from happening. For > instances outside of Hotspot, I've added casts to `unsigned char`. > > **Testing** > - Added a new test in `test/hotspot/gtest/runtime/test_os.cpp` to check > `os::is_space` is working correctly. > - tier1 Sorry I think this is well-intentioned but unnecessary in nearly all cases. If you pass a char there is no potential problem. Only passing an actual int could be a problem. src/hotspot/os/linux/cgroupSubsystem_linux.cpp line 664: > 662: char after_key = line[key_len]; > 663: if (strncmp(line, key, key_len) == 0 > 664: && os::is_space(after_key) != 0 I think this is excessive. The value is a char so cannot be a problem. The only calls to isspace that need checking are those that actually pass an int, and even then there could be adequate safeguards in place. src/hotspot/os/linux/os_linux.cpp line 1356: > 1354: if (s) { > 1355: // Skip blank chars > 1356: do { s++; } while (s && os::is_space(*s)); Again not needed. ------------- PR Review: https://git.openjdk.org/jdk/pull/19567#pullrequestreview-2103234054 PR Review Comment: https://git.openjdk.org/jdk/pull/19567#discussion_r1630265925 PR Review Comment: https://git.openjdk.org/jdk/pull/19567#discussion_r1630266490
