clone3 - Linux

Overview

clone3 is a powerful Linux command that creates a new process (task). It’s an extended version of clone that provides additional process isolation and resource management capabilities. It’s designed for advanced users who need fine-grained control over process behavior.

Syntax

clone3(flags) -> pid_t

Options/Flags

  • CLONE_NEWNS: Creates a new mount namespace for the child process.
  • CLONE_NEWPID: Creates a new PID namespace for the child process.
  • CLONE_NEWUSER: Creates a new user namespace for the child process.
  • CLONE_NEWUTS: Creates a new UTS namespace for the child process.
  • CLONE_NEWIPC: Creates a new IPC namespace for the child process.
  • CLONE_NEWNET: Creates a new network namespace for the child process.
  • CLONE_NEWCGROUP: Creates a new cgroup namespace for the child process.
  • CLONE_NEWTIME: Creates a new time namespace for the child process.

Examples

Create a child process in a new mount namespace:

clone3(CLONE_NEWNS)

Create a child process in a new PID namespace:

clone3(CLONE_NEWPID)

Create a child process in a new user namespace:

clone3(CLONE_NEWUSER)

Common Issues

  • Ensure you have sufficient privileges to use clone3.
  • Avoid creating too many nested namespaces, as it can lead to resource exhaustion.
  • Be aware that processes in different namespaces are isolated and cannot directly access resources in other namespaces.

Integration

clone3 can be combined with other commands for advanced tasks:

  • Use unshare to create namespaces on an existing process.
  • Use setns to move a process into a different namespace.
  • Use pidfd_send_signal to send signals to processes in other namespaces.

Related Commands

  • clone
  • unshare
  • setns
  • pidfd_send_signal