fix(workflow): optimize kernel-tracker.yml (#111)

* fix: attempt at optimizing kernel-tracker.yml

* fix: if condition

* fix: if condition with cache-hit

* fix: if condition change

* fix: linux repo

* fix: rename step and cache

.github/workflows/kernel-tracker.yml

@@ -17,46 +17,39 @@ jobs:
     steps:
     - name: Checkout
       uses: actions/checkout@v3
+      with:
+        path: kunai
 
-    # Define the variable (e.g., from a file or a specific command)
-    - name: Define Cache Key Variable
+    - name: Define Variable
       run: |
         LATEST_LINUX_VERSION=$(git ls-remote --tags https://github.com/torvalds/linux.git | grep -P 'refs/tags/v\d+\.\d+$' | awk '{print$NF}' | awk -F'/' '{print$NF}' | sort -V | tail -1)
-        echo "cache-key=cache-linux-$LATEST_LINUX_VERSION" >> $GITHUB_ENV
+        echo "latest-linux-version=$LATEST_LINUX_VERSION" >> $GITHUB_ENV
         
     - name: Cache
+      id: cache-linux
       uses: actions/[email protected]
       with:
         # A list of files, directories, and wildcard patterns to cache and restore
-        path: ~/linux/
+        path: ./linux/
         # An explicit key for restoring and saving the cache
-        key: ${{ env.cache-key }}
+        key: cache-linux-${{ env.latest-linux-version }}
 
     - name: Clone Kernel
-      run: |
-        set -euxo pipefail
-        if [ ! -d ~/linux ]
-        then
-          git clone https://github.com/torvalds/linux.git ~/linux
-        fi
+      # run the stuff only if we failed at retrieve from cache
+      if: steps.cache-linux.outputs.cache-hit != 'true'
+      uses: actions/checkout@v3
+      with:
+        repository: torvalds/linux
+        ref: ${{ env.latest-linux-version }}
+        path: ./linux
 
-    - name: Checkout Latest Kernel
-      run: |
-        set -euxo pipefail
-        cd ~/linux
-        git checkout master
-        git pull
-        # checkout to latest stable version       
-        LATEST_VERSION=$(git tag | grep -P 'v\d+\.\d+$' | sort -V | tail -n 1)
-        git checkout $LATEST_VERSION
-
     - name: Test Kunai Hooks
       run: |
         set -euxo pipefail
         # we get kernel functions prototypes
-        grep -oPR --include='*.h' --include='*.c' '^(\w+\s+)+\w+\(' ~/linux | awk '{print$NF}' | tr -d '(' | sort -u > linux.sym
+        grep -oPR --include='*.h' --include='*.c' '^(\w+\s+)+\w+\(' ./linux | awk '{print$NF}' | tr -d '(' | sort -u > linux.sym
         # we get kunai hook points (only kprobes for the moment)
-        grep -iPR '#\[k(ret)?probe.*\]' kunai-ebpf | grep -oP 'function\s+=\s+"\w+?"' | cut -d '"' -f 2 | sort -u > probes.sym
+        grep -iPR '#\[k(ret)?probe.*\]' ./kunai/kunai-ebpf | grep -oP 'function\s+=\s+"\w+?"' | cut -d '"' -f 2 | sort -u > probes.sym
         # we check that every function hooked in Kunai still exists in the kernel
         for p in $(cat probes.sym);do grep -P "^$p$" linux.sym ;done