forkexec

type ExecRLimit struct {
	TimeLimit     int // 时间限制 (ms)
	RealTimeLimit int // 真实时间限制 (ms, 触发SIGALRM)
	MemoryLimit   int // 内存限制 (KB)
	FileSizeLimit int // 文件读写限制 (B)
	StackLimit    int // 栈大小限制 (KB，0表示用内存限制的值，-1表示不限制，建议设置为2倍。Mac下有坑，不要去设置。)
}

type ITimerVal struct {
	ItInterval TimeVal
	ItValue    TimeVal
}

type ProcAttr struct {
	Dir   string    // Current working directory.
	Env   []string  // Environment.
	Files []uintptr // File descriptors.
	Sys   *SysProcAttr
}

type RLimit struct {
	Which  int
	Enable bool
	RLim   syscall.Rlimit
}

type RlimitOptions struct {
	Rlimits     []RLimit
	ITimerValue ITimerVal
}

type SysProcAttr struct {
	Chroot     string              // Chroot.
	Credential *syscall.Credential // Credential.
	// Ptrace tells the child to call ptrace(PTRACE_TRACEME).
	// Call runtime.LockOSThread before starting a process with this set,
	// and don't call UnlockOSThread until done with PtraceSyscall calls.
	Ptrace bool
	Setsid bool // Create session.
	// Setpgid sets the process group ID of the child to Pgid,
	// or, if Pgid == 0, to the new child's process ID.
	Setpgid bool
	// Setctty sets the controlling terminal of the child to
	// file descriptor Ctty. Ctty must be a descriptor number
	// in the child process: an index into ProcAttr.Files.
	// This is only meaningful if Setsid is true.
	Setctty bool
	Noctty  bool // Detach fd 0 from controlling terminal
	Ctty    int  // Controlling TTY fd
	// Foreground places the child process group in the foreground.
	// This implies Setpgid. The Ctty field must be set to
	// the descriptor of the controlling TTY.
	// Unlike Setctty, in this case Ctty must be a descriptor
	// number in the parent process.
	Foreground   bool
	Pgid         int                    // Child's process group ID if Setpgid.
	Pdeathsig    syscall.Signal         // Signal that the process will get when its parent dies (Linux only)
	Cloneflags   uintptr                // Flags for clone calls (Linux only)
	Unshareflags uintptr                // Flags for unshare calls (Linux only)
	UidMappings  []syscall.SysProcIDMap // User ID mappings for user namespaces.
	GidMappings  []syscall.SysProcIDMap // Group ID mappings for user namespaces.
	// GidMappingsEnableSetgroups enabling setgroups syscall.
	// If false, then setgroups syscall will be disabled for the child process.
	// This parameter is no-op if GidMappings == nil. Otherwise for unprivileged
	// users this should be set to false for mappings work.
	GidMappingsEnableSetgroups bool
	AmbientCaps                []uintptr  // Ambient capabilities (Linux only)
	Rlimit                     ExecRLimit // Set child's rlimit.
}

type TimeVal struct {
	TvSec  uint64
	TvUsec uint64
}