#Judger [developing]

Judger for OnlineJudge

build

sudo apt-get install libseccomp-dev
mkdir build && cd build && cmake .. && make && sudo make install

C API

#include <runner.h> then call run function with struct config and struct result pointer.

struct config members

• max_cpu_time(ms): max cpu time this process can cost, -1 for unlimited
• max_real_time(ms): max time this process can run, -1 for unlimited
• max_memory(byte): max size of the process's virtual memory (address space), -1 for unlimited
• max_process_number: max number of child process this process can create (to avoid fork bomb), -1 for unlimited
• max_output_size(byte): max size of data this process can output to stdout, stderr and file, -1 for unlimited
• exe_path: path of file to run
• input_file: redirect content of this file to process's stdin
• output_file: redirect process's stdout to this file
• error_file: redirect process's stderr to this file
• args(string array terminated by NULL): arguments to run this process
• env(string array terminated by NULL): environment variables this process can get
• log_path: judger log path
• seccomp_rule_so_path(string or NULL): seccomp rules used to limit process system calls
• uid: user to run this process
• gid: user group this process belongs to

struct result members

• cpu_time: cpu time the process has used
• real_time: actual running time of the process
• signal: signal number
• exit_code: process's exit code
• result: judger result, details in runner.h
• error: args validation error or judger internal error, error code in runner.h

Python binding (Python 2.7 only)

sudo python setup.py install

Python demo

>>> import _judger
>>> _judger.run(max_cpu_time=1000,
...             max_real_time=2000,
...             max_memory=1000000000,
...             max_process_number=200,
...             max_output_size=10000,
...             # five args above can be _judger.UNLIMITED
...             exe_path="/bin/echo",
...             input_path="/dev/null",
...             output_path="echo.out",
...             error_path="echo.out",
...             # can be empty list
...             args=["HelloWorld"],
...             # can be empty list
...             env=["foo=bar"],
...             log_path="judger.log",
...             # can be None
...             seccomp_rule_so_path="/usr/lib/judger/librule_c_cpp.so",
...             uid=0,
...             gid=0)

{'cpu_time': 0, 'signal': 0, 'memory': 4554752, 'exit_code': 0, 'result': 0, 'error': 0, 'real_time': 2}

Run tests

cd tests &&  sudo python test.py

Note

• Linux x64 and kernel version > 3.17 required
• Judger security relies on Docker with default security config More
• Tested under Ubuntu 14.04 docker container. System calls may vary due to different system and kernel versions
• Root user required to change uid / gid
• Why use seccomp instead of ptrace? Ptrace can decrease process's performance significantly, for each system call, twice context switch between child process and parent process is needed.
• How to custom seccomp rule? Example here and then reinstall jduger, your code will be compiled and installed under /usr/lib/judger

License

The Star And Thank Author License (SATA)