Add initial QVM CLI, Nix flake, scripts and README

bin/qvm-run

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+#!/usr/bin/env bash
+#
+# qvm-run - Execute a command in the VM workspace
+#
+# This script:
+# 1. Ensures VM is running (auto-starts if needed)
+# 2. Registers current $PWD as a workspace in workspaces.json
+# 3. SSHes into VM and executes command in workspace mount point
+# 4. Streams output and preserves exit code
+#
+# Usage: qvm-run <command> [args...]
+#
+# Notes:
+# - Workspaces are pre-mounted at VM start time (no dynamic 9p hotplug)
+# - If workspace not already registered, warns to restart VM
+# - Uses workspace hash for mount tag and path
+#
+
+set -euo pipefail
+
+# Source common library
+QVM_LIB_DIR="${QVM_LIB_DIR:-$(dirname "$(readlink -f "$0")")/../lib}"
+# shellcheck source=lib/common.sh
+source "$QVM_LIB_DIR/common.sh"
+
+#
+# show_usage - Display usage information
+#
+show_usage() {
+    cat <<EOF
+Usage: qvm run <command> [args...]
+
+Execute a command in the VM at the current workspace directory.
+
+The current directory (\$PWD) is automatically registered as a workspace
+and mounted into the VM. Commands run in the mounted workspace directory.
+
+Examples:
+  qvm run cargo build
+  qvm run npm install
+  qvm run ls -la
+  qvm run bash -c "pwd && ls"
+
+Notes:
+  - Workspaces are mounted at VM start time
+  - If this workspace is new, you'll need to restart the VM
+  - Command output streams to your terminal
+  - Exit code matches the command's exit code
+
+EOF
+}
+
+#
+# register_workspace - Add workspace to registry if not already present
+# Args: $1 - absolute path to workspace
+#       $2 - workspace hash
+# Returns: 0 if already registered, 1 if newly added (requires VM restart)
+#
+register_workspace() {
+    local workspace_path="$1"
+    local hash="$2"
+    local mount_tag="ws_${hash}"
+    local guest_path="/workspace/${hash}"
+    
+    # Create workspaces.json if it doesn't exist
+    if [[ ! -f "$QVM_WORKSPACES_FILE" ]]; then
+        echo '[]' > "$QVM_WORKSPACES_FILE"
+    fi
+    
+    # Check if workspace already registered
+    if jq -e --arg path "$workspace_path" '.[] | select(.host_path == $path)' "$QVM_WORKSPACES_FILE" >/dev/null 2>&1; then
+        log_info "Workspace already registered: $workspace_path"
+        return 0
+    fi
+    
+    # Add new workspace to registry
+    log_info "Registering new workspace: $workspace_path"
+    local temp_file
+    temp_file=$(mktemp)
+    
+    jq --arg path "$workspace_path" \
+       --arg hash "$hash" \
+       --arg tag "$mount_tag" \
+       --arg guest "$guest_path" \
+       '. += [{
+           host_path: $path,
+           hash: $hash,
+           mount_tag: $tag,
+           guest_path: $guest
+       }]' "$QVM_WORKSPACES_FILE" > "$temp_file"
+    
+    mv "$temp_file" "$QVM_WORKSPACES_FILE"
+    log_info "Workspace registered as $mount_tag -> $guest_path"
+    
+    return 1  # Indicate new workspace added
+}
+
+#
+# is_workspace_mounted - Check if workspace is actually mounted in VM
+# Args: $1 - SSH port
+#       $2 - guest path
+# Returns: 0 if mounted, 1 if not
+#
+is_workspace_mounted() {
+    local ssh_port="$1"
+    local guest_path="$2"
+    
+    # SSH into VM and check if guest path exists and is a directory
+    if ssh -o StrictHostKeyChecking=no \
+           -o UserKnownHostsFile=/dev/null \
+           -o LogLevel=ERROR \
+           -p "$ssh_port" \
+           root@localhost \
+           "test -d '$guest_path'" 2>/dev/null; then
+        return 0
+    else
+        return 1
+    fi
+}
+
+#
+# main - Main execution flow
+#
+main() {
+    # Show usage if no arguments
+    if [[ $# -eq 0 ]]; then
+        show_usage
+        exit 1
+    fi
+    
+    # Handle help flags
+    if [[ "$1" == "-h" || "$1" == "--help" ]]; then
+        show_usage
+        exit 0
+    fi
+    
+    # Get current workspace (absolute path)
+    local workspace_path
+    workspace_path="$(pwd)"
+    
+    # Generate workspace hash
+    local hash
+    hash=$(workspace_hash "$workspace_path")
+    
+    local guest_path="/workspace/${hash}"
+    
+    log_info "Workspace: $workspace_path"
+    log_info "Guest path: $guest_path"
+    
+    # Register workspace in registry
+    local newly_added=0
+    if ! register_workspace "$workspace_path" "$hash"; then
+        newly_added=1
+    fi
+    
+    # Ensure VM is running
+    if ! is_vm_running; then
+        log_info "VM not running, starting..."
+        
+        # Path to qvm-start script
+        local qvm_start="${QVM_LIB_DIR}/../bin/qvm-start"
+        
+        if ! "$qvm_start"; then
+            die "Failed to start VM"
+        fi
+    fi
+    
+    # Get SSH port
+    local ssh_port
+    ssh_port=$(get_ssh_port)
+    
+    # Check if workspace is actually mounted in VM
+    if ! is_workspace_mounted "$ssh_port" "$guest_path"; then
+        log_error "Workspace not mounted in VM"
+        echo ""
+        echo "This workspace was just registered but is not mounted in the VM."
+        echo "Workspaces must be mounted at VM start time."
+        echo ""
+        echo "Please restart the VM to mount this workspace:"
+        echo "  qvm stop"
+        echo "  qvm start"
+        echo ""
+        echo "Then try your command again."
+        exit 1
+    fi
+    
+    # Build SSH command
+    # - Use -t if stdin is a TTY (for interactive commands)
+    # - Suppress SSH warnings (ephemeral VM, host keys change)
+    # - cd to guest path and execute command
+    local ssh_cmd=(
+        ssh
+        -o StrictHostKeyChecking=no
+        -o UserKnownHostsFile=/dev/null
+        -o LogLevel=ERROR
+        -p "$ssh_port"
+    )
+    
+    # Add -t flag if stdin is a TTY
+    if [[ -t 0 ]]; then
+        ssh_cmd+=(-t)
+    fi
+    
+    # Add connection target
+    ssh_cmd+=(root@localhost)
+    
+    # Build remote command: cd to workspace and execute user's command
+    # Quote each argument properly to handle spaces and special chars
+    local remote_cmd="cd '$guest_path' && "
+    
+    # Append user's command with proper quoting
+    local first_arg=1
+    for arg in "$@"; do
+        if [[ $first_arg -eq 1 ]]; then
+            remote_cmd+="$arg"
+            first_arg=0
+        else
+            # Quote arguments that contain spaces or special characters
+            if [[ "$arg" =~ [[:space:]] ]]; then
+                remote_cmd+=" '$arg'"
+            else
+                remote_cmd+=" $arg"
+            fi
+        fi
+    done
+    
+    # Add the remote command as final SSH argument
+    ssh_cmd+=("$remote_cmd")
+    
+    # Execute SSH command (replaces current process)
+    exec "${ssh_cmd[@]}"
+}
+
+# Run main function
+main "$@"