[crac] RFR: Fix: arguments supplied to restore are split with whitespace

[Anton Kozlov]

On Thu, 10 Aug 2023 16:02:32 GMT, null <duke at openjdk.org> wrote:

> This PR fixes a bug that causes arguments with whitespaces to be split into multiple arguments during restore.
> 
> It contains two commits. The first commit is refactor only. It moves all side effects from `CracRestoreParameters` to the call sites, and changes the type of `CracRestoreParameters::args` from a single string to a `GrowableArray` of strings. Serialization code is also cleaned up a bit.
> 
> The second commit fixes the bug by introducing a new pseudo property, `-DCRaCJavaMainArgs`, that is set in `JavaMain`. An instance of `JavaMainArgs` (containing `argc` and `argv`) is stored as extra info of the property, which is later extracted in `Arguments::parse_options_for_restore` and passed to `crac::restore`.
> 
> Potential issues:
> 
> * We use `putenv` to modify environment variables, which expects `char*`. In this PR, I'm `const_cast`ing from `const char*` to `char*`, since I believe `putenv` doesn't actually modify the string. Is that OK? Maybe rewriting with `setenv` would be better?
> * `read_growable_array` is implemented by reading byte-at-a-time from the shared memory. Will it be too slow? I could rewrite it to read everything at once (like the original code did), but the current implementation is cute and I kinda want to keep it.

Would you mind rebasing the PR?

src/hotspot/share/runtime/arguments.cpp line 2287:

> 2285:         }
> 2286:       }
> 2287:       else if (strcmp(key, "jdk.internal.crac.mainArgs") == 0) {

Nit: please use One-True-Brace-Style https://github.com/openjdk/jdk/blob/master/doc/hotspot-style.md#whitespace

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PR Review: https://git.openjdk.org/crac/pull/101#pullrequestreview-1700515230
PR Review Comment: https://git.openjdk.org/crac/pull/101#discussion_r1373726907