# UP - Embedded Linux Update Server

A Go-based HTTP server for managing embedded Linux system updates, designed for Orange Pi Zero 2W (Allwinner H618) and similar ARM-based devices.

## Overview

This server provides a web interface and REST API for:
- Uploading and managing boot files (U-Boot, kernel, DTB)
- Editing extlinux boot configuration
- Monitoring system temperature
- Remote system reboot
- File version tracking

## Project Structure

```
up/
├── main.go              # Application entry point
├── go.mod               # Go module definition
├── up.conf              # Environment configuration file
├── api/                 # HTTP handlers
│   ├── frontend/        # Embedded web UI (HTML, CSS, JS)
│   ├── Extlinux.go      # Boot config read/write router
│   ├── ExtlinuxRead.go  # Read extlinux.conf
│   ├── ExtlinuxWrite.go # Write extlinux.conf
│   ├── FileDate.go      # Get file version timestamps
│   ├── HandleReboot.go  # System reboot endpoint
│   ├── HandleTemperature.go # Temperature monitoring
│   ├── HandleUpload.go  # File upload handler
│   ├── MountStatus.go   # Mount status checker
│   └── spa.go           # SPA file server
├── server/              # Server configuration
│   ├── Configure.go     # Route configuration
│   └── Run.go           # Server startup (HTTP/HTTPS)
└── utils/               # Utility functions
    ├── mtd/             # MTD (Memory Technology Device) utilities
    ├── EnsureDir.go     # Directory creation
    ├── GetTargetFilename.go # Filename resolution by type
    ├── LoadEnv.go       # Environment loader
    ├── MountDevice.go   # Device mounting
    └── WriteUbootToDevices.go # U-Boot flashing
```

## Configuration

The server uses `up.conf` (dotenv format) for configuration:

```env
ENABLE_TLS=false                    # Enable HTTPS
CERT_FILE=cert.crt                  # TLS certificate path
KEY_FILE=privkey.key                # TLS key path
SERVER_ADDRESS=0.0.0.0              # Bind address
SERVER_PORT=8989                    # Bind port
MOUNT_POINT=/media                  # Mount point for target device
DEVICE=/dev/mmcblk1p1               # Target block device
KERNEL_FILE=Image.gz                # Kernel image filename
DTB_FILE=sun50i-h618-orangepi-zero2w.dtb  # Device tree blob
UBOOT_FILE=uboot.env                # U-Boot environment file
EXTLINUX_FILE=extlinux/extlinux.conf # Bootloader config
MAX_FILE_SIZE=200                   # Max upload size (MB)
UBOOT_BIN_FILE=u-boot-sunxi-with-spl.bin # U-Boot binary
UBOOT_MAX_SIZE=1                    # Max U-Boot size (MB)
MMC_BOOT_OFFSET=8192                # MMC boot offset
```

## API Endpoints

| Endpoint | Method | Description |
|----------|--------|-------------|
| `/` | GET | Web UI (SPA) |
| `/api/mount` | GET | Get mount status |
| `/api/extlinux` | GET | Read extlinux.conf |
| `/api/extlinux` | POST | Write extlinux.conf |
| `/api/filedate` | GET | Get file version date |
| `/api/temperature` | GET | Get CPU temperature |
| `/api/upload` | POST | Upload files |
| `/api/reboot` | POST | Reboot system |

### API Examples

**Get Temperature:**
```bash
curl http://localhost:8989/api/temperature
# Response: {"success":true,"temperature":45.2,"unit":"Celsius"}
```

**Upload File:**
```bash
curl -X POST -F "type=kernel" -F "file=@Image.gz" http://localhost:8989/api/upload
```

**Reboot System:**
```bash
curl -X POST http://localhost:8989/api/reboot
```

**Read Boot Config:**
```bash
curl http://localhost:8989/api/extlinux
```

**Write Boot Config:**
```bash
curl -X POST -H "Content-Type: application/json" \
  -d '{"content":"default linux\n  label linux\n  kernel /Image.gz\n"}' \
  http://localhost:8989/api/extlinux
```

## Supported Upload Types

The server supports uploading the following file types:
- `kernel` - Kernel image (Image.gz)
- `dtb` - Device tree blob
- `uboot_bin` - U-Boot bootloader
- `uboot_env` - U-Boot environment
- `extlinux` - Bootloader configuration

## Building

```bash
# Build
go build -o up

# Run
./up
```

## Requirements

- Go 1.26+
- Root privileges (for mounting devices and rebooting)
- Target storage device (eMMC/SD card)

## Features

- **Web Interface**: Embedded SPA frontend for easy management
- **TLS Support**: Optional HTTPS with certificate configuration
- **Progress Tracking**: Real-time upload progress monitoring
- **Version Tracking**: Automatic timestamp logging for uploaded files
- **Safe Reboot**: Graceful unmount and sync before reboot
- **Temperature Monitoring**: CPU thermal sensor readings