update default environment and expose as env.sh

- WORKSPACE now points to top-level user-created folder, not kafl/
- KAFL_ROOT points to WORKSPACE/kafl, where all fuzzer components reside
- KAFL_WORKDIR renamed to /dev/shm/kafl_* (similar to old default and not -tdfl)

The resulting '.env' is now exposed as more obvious entry point 'env.sh'
that also initializes the correct python venv for kAFL.

The old hidden '.env' only made sense in combination with pipenv, which
in turn has been deprecated by ansible/virtualenv setup.

.gitignore

@@ -1,7 +1,9 @@
 # IDE
 .vscode/
+ctags
 
 # Python venvs
+/env.sh
 venv/
 .venv/
 

deploy/intellabs/kafl/roles/fuzzer/tasks/post_tasks.yml

@@ -24,4 +24,4 @@
 - name: Create .env file
   template:
     src: env.j2
-    dest: "{{ kafl_install_root }}/.env"
+    dest: "{{ install_root }}/env.sh"

deploy/intellabs/kafl/roles/fuzzer/templates/env.j2

@@ -1,8 +1,17 @@
-export WORKSPACE="{{ kafl_install_root }}"
-export KAFL_ROOT="{{ fuzzer_root }}"
+# source this file to activate the environment,
+# or use "make env" to start a sub-shell
+
+# components managed by ansible
+export KAFL_ROOT="{{ kafl_install_root }}"
 export QEMU_ROOT="{{ qemu_root }}"
 export LIBXDC_ROOT="{{ libxdc_root }}"
 export CAPSTONE_ROOT="{{ capstone_root }}"
 export RADAMSA_ROOT="{{ radamsa_root }}"
+
+# workspace defaults
+export WORKSPACE="{{ install_root }}"
 export KAFL_CONFIG_FILE="{{ fuzzer_root }}/kafl.yaml"
-export KAFL_WORKDIR="/dev/shm/{{ ansible_user_id }}_tdfl"
+export KAFL_WORKDIR="/dev/shm/kafl_{{ ansible_user_id }}"
+
+# activate python venv
+source $KAFL_ROOT/.venv/bin/activate