Add undocumented config options to docs (#124)

* Add parallel-fuzzing option
 to docs

* Document more options

* Add options to build integrations

* Small fixes to gitlab.md

Author: securitykernel

docs/running-clusterfuzzlite/github_actions.md

@@ -102,6 +102,7 @@ Optionally, edit the following fields to customize your settings:
 - `language` Change to the language of your target code.
 - `sanitizers` Change or enable more sanitizers.
 - `fuzz-seconds` Change the amount of time spent fuzzing.
+- `parallel-fuzzing`: Use all available CPU cores for fuzzing.
 - `storage-repo`, `storage-repo-branch`,
   `storage-repo-branch-coverage` Enable a [storage repo] (not necessary for initial runs, but a useful feature discussed [later on]).
 
@@ -168,6 +169,7 @@ Optionally, edit the following fields to customize your settings:
 - `cron` Change how frequently batch fuzzing is run. See [GitHub's documentation] on this.
 - `sanitizers` Change or enable more sanitizers.
 - `fuzz-seconds` Change the amount of time spent fuzzing.
+- `parallel-fuzzing`: Use all available CPU cores for fuzzing.
 - `storage-repo`, `storage-repo-branch`,
   `storage-repo-branch-coverage` Enable a [storage repo].
 

docs/running-clusterfuzzlite/gitlab.md

@@ -87,6 +87,7 @@ Optionally, edit the following variables to customize your settings:
 - `CFL_BRANCH` Branch to fuzz, default is `CI_DEFAULT_BRANCH`.
 - `FILESTORE` storage for files: builds, corpus, coverage and crashes.
 - `FUZZ_SECONDS` Change the amount of time spent fuzzing.
+- `PARALLEL_FUZZING` Use all available cores when fuzzing.
 - `CFL_ARTIFACTS_DIR` To save your artifacts in a different directory than `artifacts`
 
 ### Batch fuzzing and corpus pruning
@@ -136,8 +137,8 @@ keyword to avoid duplicating most of the common parameters between the different
 The continuous build task causes a build to be triggered and uploaded
 whenever a new push is done to main/default branches.
 
-Continuous builds are used when a crash is found during PR fuzzing to determine whether the crash was newly introduced.
-If the crash was not newly introduced, PR fuzzing will not report it.
+Continuous builds are used when a crash is found during MR fuzzing to determine whether the crash was newly introduced.
+If the crash was not newly introduced, MR fuzzing will not report it.
 This means that there will be fewer unrelated failures when running code change
 fuzzing.
 
@@ -212,7 +213,7 @@ From a performance point of view, it is recommended to use a `docker` gitlab run
 See this [doc](https://docs.gitlab.com/ee/ci/docker/using_docker_build.html#use-docker-socket-binding)
 for more information.
 
-To do so, if you have such a runner ready, you simply need to remove the following lines from the configuration :
+To do so, if you have such a runner ready, you simply need to remove the following lines from the configuration:
 {% raw %}
 ```yaml
 variables:
@@ -249,7 +250,7 @@ For continuous builds, you need to use a [cache](https://docs.gitlab.com/ee/ci/c
       - cfl-cache/
 ```
 {% endraw %}
-The cache directory needs to defined as `CFL_CACHE_DIR` to be used by ClusterFuzzLite.
+The cache directory needs to be defined as `CFL_CACHE_DIR` to be used by ClusterFuzzLite.
 If it is not defined, the default value is `cache`.
 You should ensure that the runners share the access to the cache.
 
@@ -263,7 +264,7 @@ project access token, due to your Gitlab license.
 
 ![gitlab-project-token]
 
-And this token should be used from the fuzzed repository as a CI/CD variable.
+Add the token as a CI/CD variable to your GitLab project.
 You can name this variable as you like, in the following example it is named
 `CFL_TOKEN`. This variable should be defined as masked to avoid leaks.
 It should not be protected if you need it on unprotected branches.

docs/running_clusterfuzzlite.md

@@ -153,6 +153,26 @@ specific CI system.
   coverage report generation). The default is `'address'`.
   See [Sanitizers] for more information.
 
+- `parallel-fuzzing`: Whether to use all available CPU cores for fuzzing.
+  The default value is `false`, which only uses a single CPU core.
+  When set to `true`, ClusterFuzzLite runs multiple fuzzer processes
+  in parallel with a shared corpus directory. New inputs found by one
+  fuzzer process will be available to the other fuzzer processes.
+  The number of cores available depends on your specific CI system.
+
+- `report-unreproducible-crashes`: Whether to report unreproducible crashes.
+  The default value is `false`. ClusterFuzzLite will always attempt to reproduce
+  new crashes. Sometimes crashes can not be reproduced reliably, e.g.,
+  because the fuzz target is in a different state. Read more on
+  non-reproducible bugs in 
+  [this section](https://google.github.io/oss-fuzz/advanced-topics/bug-fixing-guidance#non-reproducible-bugs).
+  When set to `true`, even non-reproducable bugs will be reported a
+  as failure.  
+
+- `minimize-crashes`: If `true`, reportable crashes will be minimized.
+  The default value is `false`. Minimizing crashes reduces fuzzing time
+  in batch fuzzing.
+
 - `mode`: The mode for ClusterFuzzLite to execute. `code-change` by default. See
   [ClusterFuzzLite modes] for more details on how to run different modes.