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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.
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