L2 Crash Sender

A lightweight C++ crash report sender utility designed to automatically upload crash dumps and error information to a remote server. Built with modern C++20 practices and robust error handling.

Features

• Automatic Crash Report Upload: Sends crash dumps and error logs to a configured server endpoint
• Command-line Interface: Simple parameter-based configuration
• Robust Error Handling: Comprehensive logging and graceful failure recovery
• Windows Native: Optimized for Windows using WinINet API

Build Requirements

• Compiler: MSVC with C++20 support (Visual Studio 2019 16.11+ or Visual Studio 2022)
• CMake: Version 3.20 or higher
• Platform: Windows (uses Windows API and WinINet)
• Dependencies: Windows SDK (wininet.lib)

Building

# Configure the project
cmake -B build -S . -DCMAKE_BUILD_TYPE=Release

# Build the executable
cmake --build build --config Release

# The executable will be in build/bin/L2CrashSender.exe

Usage

The application is designed to be called automatically by crash reporting systems. It requires four command-line parameters:

L2CrashSender.exe -url=http://example.com/crashreport -version=1.0.0 -error=C:\temp\error.txt -dump=C:\temp\crashdump.dmp

Parameters

Parameter	Description	Required
-url=	Server endpoint URL for crash reports	Yes
-version=	Application version string	Yes
-error=	Path to error description file (UTF-16 format)	Yes
-dump=	Path to crash dump file	Yes

Example

L2CrashSender.exe -url=https://crash-server.example.com/api/submit -version=2.1.3 -error=C:\temp\app_error.txt -dump=C:\temp\app_crash.dmp

Architecture

The application follows a modular design with clear separation of concerns:

CrashSender/
├── main.cpp              # Application entry point
├── main.h                # Main application interface
├── crash_report_data.h   # Data structure definitions
├── crash_report_data.cpp # Data validation and management
├── command_line_parser.h # Command line argument processing
├── command_line_parser.cpp
├── http_client.h         # HTTP communication
├── http_client.cpp
├── logger.h              # Logging system
├── logger.cpp
├── utils.h               # Utility functions
├── utils.cpp
└── CMakeLists.txt        # Build configuration

Key Components

CrashReportData

• Validates and stores crash report information
• Ensures data integrity before transmission

CommandLineParser

• Parses command-line arguments safely
• Processes error file content and server URLs
• Provides detailed error messages for debugging

HttpClient

• Handles HTTP communication using WinINet
• Creates multipart form data for file uploads
• Manages connection lifecycle and error recovery

Logger

• Thread-safe singleton logging system
• Configurable log levels (Debug, Info, Error)
• Automatic timestamping and file output

Utils

• Text conversion utilities (Wide ↔ UTF-8)
• File system operations with RAII
• Time formatting functions

HTTP Protocol

The application sends crash reports using HTTP POST with multipart form data:

Request Format

POST /api/crashreport HTTP/1.1
Host: crash-server.example.com
Content-Type: multipart/form-data; boundary=MULTIPART-DATA-BOUNDARY
Content-Transfer-Encoding: binary

--MULTIPART-DATA-BOUNDARY
Content-Disposition: form-data; name="CRVersion"

1.0.0
--MULTIPART-DATA-BOUNDARY
Content-Disposition: form-data; name="error"

Application crash details...
--MULTIPART-DATA-BOUNDARY
Content-Disposition: form-data; name="dumpfile"; filename="crash.dmp"
Content-Type: application/octet-stream

[Binary crash dump data]
--MULTIPART-DATA-BOUNDARY--

Response Handling

• 2xx: Success - temporary files are cleaned up
• 4xx/5xx: Error - detailed error message logged
• Network errors: Timeout/connection failures logged

Logging

The application creates a log file L2CrashSender.log in the current directory with detailed execution information:

2024-01-15 14:30:25.123 [INF] L2CrashSender started
2024-01-15 14:30:25.124 [DBG] Version: 1.0.0
2024-01-15 14:30:25.125 [DBG] Connecting to server: crash-server.example.com
2024-01-15 14:30:25.200 [DBG] Total upload size: 1048576 bytes
2024-01-15 14:30:26.150 [DBG] Server responded with status: 200
2024-01-15 14:30:26.151 [INF] Crash report sent successfully
2024-01-15 14:30:26.152 [INF] L2CrashSender finished

Error Handling

The application implements robust error handling:

• Invalid arguments: Clear error messages for missing/malformed parameters
• File access errors: Graceful handling of missing or locked files
• Network failures: Detailed HTTP error reporting with server responses
• Resource cleanup: Automatic cleanup even on failure paths
• Exception safety: All operations are exception-safe with RAII

Security Considerations

• File validation: Basic validation of input file paths and sizes
• Memory safety: Modern C++ with automatic memory management
• Buffer overflow protection: Bounds checking on all file operations

Integration Example

For integration with crash reporting frameworks:

// Example integration with a crash handler
void OnApplicationCrash(const std::wstring& dumpPath, const std::wstring& errorDesc) {
    // Write error description to temporary file
    std::wstring errorFile = WriteErrorToTempFile(errorDesc);
    
    // Launch crash sender
    std::wstring commandLine = L"L2CrashSender.exe "
        L"-url=https://crashes.myapp.com/submit "
        L"-version=" + GetApplicationVersion() + L" "
        L"-error=" + errorFile + L" "
        L"-dump=" + dumpPath;
        
    // Execute asynchronously
    CreateProcess(nullptr, commandLine.data(), /* ... */);
}