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Michael Pratt db7917556a Fix 386 build tags 
The build tag for 32-bit x86 is 386, not i386.

Updates #2298

PiperOrigin-RevId: 304206373
 		2020-04-01 10:00:03 -07:00
..
BUILD Port most syscalls to VFS2. 2020-02-25 13:37:34 -08:00
README.md Update package locations. 2020-01-27 15:31:32 -08:00
access_type.go Update package locations. 2020-01-27 15:31:32 -08:00
addr.go Update package locations. 2020-01-27 15:31:32 -08:00
addr_range_seq_test.go Update package locations. 2020-01-27 15:31:32 -08:00
addr_range_seq_unsafe.go Update package locations. 2020-01-27 15:31:32 -08:00
bytes_io.go Update package locations. 2020-01-27 15:31:32 -08:00
bytes_io_unsafe.go Update package locations. 2020-01-27 15:31:32 -08:00
usermem.go Port most syscalls to VFS2. 2020-02-25 13:37:34 -08:00
usermem_arm64.go Update package locations. 2020-01-27 15:31:32 -08:00
usermem_test.go Update package locations. 2020-01-27 15:31:32 -08:00
usermem_x86.go Fix 386 build tags 2020-04-01 10:00:03 -07:00

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.