32 lines
1.5 KiB
Markdown
32 lines
1.5 KiB
Markdown
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This package defines primitives for sentry access to application memory.
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Major types:
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- The `IO` interface represents a virtual address space and provides I/O methods
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on that address space. `IO` is the lowest-level primitive. The primary
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implementation of the `IO` interface is `mm.MemoryManager`.
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- `IOSequence` represents a collection of individually-contiguous address ranges
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in a `IO` that is operated on sequentially, analogous to Linux's `struct
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iov_iter`.
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Major usage patterns:
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- Access to a task's virtual memory, subject to the application's memory
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protections and while running on that task's goroutine, from a context that is
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at or above the level of the `kernel` package (e.g. most syscall
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implementations in `syscalls/linux`); use the `kernel.Task.Copy*` wrappers
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defined in `kernel/task_usermem.go`.
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- Access to a task's virtual memory, from a context that is at or above the
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level of the `kernel` package, but where any of the above constraints does not
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hold (e.g. `PTRACE_POKEDATA`, which ignores application memory protections);
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obtain the task's `mm.MemoryManager` by calling `kernel.Task.MemoryManager`,
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and call its `IO` methods directly.
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- Access to a task's virtual memory, from a context that is below the level of
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the `kernel` package (e.g. filesystem I/O); clients must pass I/O arguments
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from higher layers, usually in the form of an `IOSequence`. The
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`kernel.Task.SingleIOSequence` and `kernel.Task.IovecsIOSequence` functions in
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`kernel/task_usermem.go` are convenience functions for doing so.
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