Add ripcord/ripcord.sh

ripcord/ripcord.sh

@@ -0,0 +1,79 @@
+#!/bin/sh
+
+# ==============================================================================
+# Ripcord - Your server's last-ditch emergency disk space release.
+#
+# This script runs once on first boot to create a large "ballast" file.
+# Deleting this file in an emergency frees up critical disk space.
+# The data is from /dev/urandom to ensure it is not compressible by ZFS/lz4.
+# ==============================================================================
+
+# --- Configuration ---
+
+# Percentage of the total root filesystem size to use for the emergency file.
+PERCENTAGE=5
+
+# The emergency file. The name itself is the instruction.
+# It contains the project name for easy identification.
+TARGET_FILE="/RIPCORD_EMERGENCY_DELETE_FOR_DISK_SPACE.dat"
+
+# A flag file to ensure this script only ever runs once.
+FLAG_FILE="/var/log/ripcord-deployed.flag"
+
+# --- Script Logic ---
+
+# Function to log messages with a timestamp
+log() {
+    echo "$(date '+%Y-%m-%d %H:%M:%S') - $1"
+}
+
+# 1. Check if Ripcord has already been deployed
+if [ -f "$FLAG_FILE" ]; then
+    log "Ripcord has already been deployed. Exiting."
+    exit 0
+fi
+
+log "--- Deploying Ripcord ---"
+
+# 2. Create the emergency ballast file
+if [ -f "$TARGET_FILE" ]; then
+    log "Warning: Ripcord target file '$TARGET_FILE' already exists. Skipping creation."
+else
+    log "Preparing to create Ripcord ballast file at '$TARGET_FILE'."
+
+    # Get total size of '/' in Kilobytes using the POSIX standard format.
+    total_kb=$(df -Pk / | tail -1 | awk '{print $2}')
+
+    if [ -z "$total_kb" ]; then
+        log "Error: Could not determine total disk size for '/'."
+        exit 1
+    fi
+
+    log "Total size of root filesystem: ${total_kb} KB."
+
+    # Calculate the target file size in Kilobytes.
+    target_size_kb=$(( (total_kb * PERCENTAGE) / 100 ))
+
+    log "Target ballast file size will be ${PERCENTAGE}% of total: ${target_size_kb} KB."
+
+    # Use dd to create the file from /dev/urandom.
+    # This data is uncompressible, which is critical for filesystems like ZFS.
+    log "Creating file from /dev/urandom... This may take a significant amount of time."
+    dd if=/dev/urandom of="$TARGET_FILE" bs=1024 count="$target_size_kb" status=none 2>/dev/null
+
+    if [ $? -eq 0 ]; then
+        log "Successfully created '$TARGET_FILE'."
+    else
+        log "Error: dd command failed to create '$TARGET_FILE'."
+        rm -f "$TARGET_FILE" # Clean up partial file on failure
+        exit 1
+    fi
+fi
+
+# 3. Create the flag file to prevent this script from running again
+log "Creating deployment flag at '$FLAG_FILE'."
+touch "$FLAG_FILE"
+
+log "--- Ripcord deployment complete ---"
+
+exit 0