Rongsong Shen
5df33e69d9
xcecd runs as root and kept files at fixed names in world-writable /tmp, opened by path: - main.c created <logdir or /tmp>/xcecd_worker.log and then chmod(path, 0666)'d it: a symlink planted there made root chmod 0666 any file (e.g. /etc/shadow). - process_worker_manager.c appended xcecd_worker's stdout/stderr to /tmp/xcecd_worker.log through any planted symlink/hardlink. - xcecd_prepare_restart() created /tmp/.xcecd.restarting through a dangling symlink (an empty root-owned file anywhere), and xcecd_check_restart_type() trusted access() on it, so any user could make an unplanned restart look planned. xcecd_tmpfile.h: - xcecd_open_owned_file(): reuses an existing file only if it is our own regular single-link file (so a legitimate log keeps being appended to); otherwise unlinks whatever is there and creates a fresh file with O_EXCL|O_NOFOLLOW. O_NONBLOCK so a planted FIFO cannot hang startup. - xcecd_owned_file_exists(): lstat-based; only our own regular file counts as the restart flag. Anything else at the name is removed and ignored. - The worker log's 0666 mode is now set with fchmod() on the fd. New test_xcecd_tmpfile.c (7 tests; with the old behaviour the symlink, dangling-symlink and hardlink cases FAIL and the FIFO case hangs); worker suite 12/12. Sequential HA soak (5 rounds, xcecd_virtual) PASS. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> |
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| CLAUDE.md | ||
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Cross-Platform Xcecd Process
This is a cross-platform process manager implementation in C that supports both Linux and Windows platforms. The xcecd provides the following features:
- Sending status to the remote controller module at port 6789 and receive job requests
- Maintains a configurable thread pool for request processing
- Periodically collects and updates system resource status
- Manages child processes spawned from received commands
- Caches job status information
- Uses Unix Domain Sockets for communication between the main process and worker processes
Building
Prerequisites
- C compiler with C11 support
- Windows: Visual Studio
- Linux: GCC and development tools
Build Instructions
On Linux
make
On Windows
nmake
Configuration
The xcecd can be configured through the following parameters in main.c:
thread_pool_size: Number of threads in the thread pool (default: 4)resource_update_interval: Interval for updating system resource status in seconds (default: 1)job_status_update_interval: Interval for updating job status in seconds (default: 1)port: Port number to listen on (default: 7869)acct_file_path: Path to the accounting file (default:/tmp/xcecd.acct)log_file_path: Path to the log file (default:/tmp/xcecd.log)domain_sock_path: Path to the Unix Domain Socket file (default:/tmp/xcecd.sock)remote_host: Remote server address (default:lchen02)remote_port: Remote server port (default: 6789)update_interval: Interval for sending status updates to the remote server (default: 1 second)
Usage
Starting the Xcecd
On Windows:
xcecd.exe
On Linux:
./xcecd
Features
-
Cross-Platform Support
- Works on both Windows and Linux
- Abstracts platform-specific implementations
-
Thread Pool
- Configurable number of worker threads
- Efficient request handling
-
System Monitoring
- CPU usage monitoring
- Memory usage monitoring
- Disk space monitoring
-
Process Management
- Spawns child processes for received commands
- Tracks process status
- Manages process lifecycle
-
Network Communication
- TCP socket-based communication
- Simple text-based protocol
-
Unix Domain Socket Communication
- Uses Unix Domain Sockets for communication between the main process and worker processes
Architecture
The xcecd is composed of several key components:
- Main Process: Coordinates all components and manages the lifecycle
- Thread Pool: Handles concurrent request processing
- System Monitor: Collects and updates system resource information
- Process Manager: Manages child processes and their status
- Network Handler: Handles network communication and request receiving
- Resource Sync: Synchronizes and aggregates resource collection thread, system monitor, and job information
Contributing
Feel free to submit issues and enhancement requests!