gvisor/pkg/sentry/usermem
Zhaozhong Ni be7fcbc558 stateify: support explicit annotation mode; convert refs and stack packages.
We have been unnecessarily creating too many savable types implicitly.

PiperOrigin-RevId: 206334201
Change-Id: Idc5a3a14bfb7ee125c4f2bb2b1c53164e46f29a8
2018-07-27 10:17:21 -07:00
..
BUILD stateify: support explicit annotation mode; convert refs and stack packages. 2018-07-27 10:17:21 -07:00
README.md Format documentation 2018-07-12 10:37:21 -07:00
access_type.go Check in gVisor. 2018-04-28 01:44:26 -04:00
addr.go Check in gVisor. 2018-04-28 01:44:26 -04:00
addr_range_seq_test.go Check in gVisor. 2018-04-28 01:44:26 -04:00
addr_range_seq_unsafe.go Check in gVisor. 2018-04-28 01:44:26 -04:00
bytes_io.go Check in gVisor. 2018-04-28 01:44:26 -04:00
bytes_io_unsafe.go Check in gVisor. 2018-04-28 01:44:26 -04:00
usermem.go Check in gVisor. 2018-04-28 01:44:26 -04:00
usermem_test.go Check in gVisor. 2018-04-28 01:44:26 -04:00
usermem_x86.go Check in gVisor. 2018-04-28 01:44:26 -04:00

README.md

This package defines primitives for sentry access to application memory.

Major types:

  • The IO interface represents a virtual address space and provides I/O methods on that address space. IO is the lowest-level primitive. The primary implementation of the IO interface is mm.MemoryManager.

  • IOSequence represents a collection of individually-contiguous address ranges in a IO that is operated on sequentially, analogous to Linux's struct iov_iter.

Major usage patterns:

  • Access to a task's virtual memory, subject to the application's memory protections and while running on that task's goroutine, from a context that is at or above the level of the kernel package (e.g. most syscall implementations in syscalls/linux); use the kernel.Task.Copy* wrappers defined in kernel/task_usermem.go.

  • Access to a task's virtual memory, from a context that is at or above the level of the kernel package, but where any of the above constraints does not hold (e.g. PTRACE_POKEDATA, which ignores application memory protections); obtain the task's mm.MemoryManager by calling kernel.Task.MemoryManager, and call its IO methods directly.

  • Access to a task's virtual memory, from a context that is below the level of the kernel package (e.g. filesystem I/O); clients must pass I/O arguments from higher layers, usually in the form of an IOSequence. The kernel.Task.SingleIOSequence and kernel.Task.IovecsIOSequence functions in kernel/task_usermem.go are convenience functions for doing so.