Module monitor 

Process monitoring and output collection.

Monitors the sandboxed child process using pidfd and collects stdout/stderr. Uses poll() to multiplex between:

• pidfd - Signals when child exits (no race conditions vs waitpid)
• stdout pipe - Data from child’s stdout
• stderr pipe - Data from child’s stderr
• timeout - Kills child if deadline exceeded

Output Limits

If stdout or stderr exceeds max_output, the child is killed with SIGKILL and status is set to OutputLimitExceeded. This prevents memory exhaustion from runaway output.

Exit Detection

Uses waitid(P_PIDFD, ...) to get detailed exit information:

• CLD_EXITED - Normal exit with exit code
• CLD_KILLED / CLD_DUMPED - Killed by signal

Structs

Output

Output from a sandboxed execution.

Enums

Status

Status of the sandboxed execution.

Functions

monitor

Monitor the child process and collect output.

write_stdin

Write stdin data to the child process.