211 lines
6.3 KiB
Scheme
211 lines
6.3 KiB
Scheme
(library
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(device-mapper ioctl)
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(export dm-open
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dm-close
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with-dm
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get-version
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remove-all
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list-devices
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create-device)
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(import (chezscheme)
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(fmt fmt)
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(srfi s8 receive)
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(utils))
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(define __ (load-shared-object "./device-mapper/dm-ioctl.so"))
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(define (fail msg)
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(raise
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(condition
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(make-error)
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(make-message-condition msg))))
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(define-ftype DMIoctlInterface
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(struct
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(fd int)))
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(define open% (foreign-procedure "dm_open" () (* DMIoctlInterface)))
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(define (dm-open)
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(let ((ptr (open%)))
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(if (ftype-pointer-null? ptr)
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(fail "couldn't open ioctl interface (permissions?)")
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ptr)))
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(define dm-close
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(foreign-procedure "dm_close" ((* DMIoctlInterface)) void))
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(define-syntax with-dm
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(syntax-rules ()
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((_ (name) b1 b2 ...)
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(let ((name (dm-open)))
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(dynamic-wind
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(lambda () #f)
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(lambda () b1 b2 ...)
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(lambda () (dm-close name)))))))
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(define-record-type dm-version (fields major minor patch))
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(define (get-version dm)
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(define get
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(foreign-procedure "dm_version" ((* DMIoctlInterface)
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(* unsigned-32)
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(* unsigned-32)
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(* unsigned-32)) int))
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(define (alloc-u32)
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(make-ftype-pointer unsigned-32
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(foreign-alloc (ftype-sizeof unsigned-32))))
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(define (deref-u32 p)
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(ftype-ref unsigned-32 () p))
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(let ((major (alloc-u32))
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(minor (alloc-u32))
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(patch (alloc-u32)))
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(if (zero? (get dm major minor patch))
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(let ((r (make-dm-version (deref-u32 major)
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(deref-u32 minor)
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(deref-u32 patch))))
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(foreign-free (ftype-pointer-address major))
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(foreign-free (ftype-pointer-address minor))
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(foreign-free (ftype-pointer-address patch))
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r)
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(fail "couldn't get dm version"))))
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(define (remove-all dm)
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(define do-it
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(foreign-procedure "dm_remove_all" ((* DMIoctlInterface)) int))
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(let ((r (do-it dm)))
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(unless (zero? r)
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(fail "remove-all failed"))))
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(define-ftype DevList
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(struct
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(next (* DevList))
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(major unsigned)
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(minor unsigned)
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(name (* unsigned-8))))
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(define-ftype DevListPtr (* DevList))
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(define-record-type device-details
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(fields name major minor))
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(define (cstring->string str)
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(let loop ((i 0)
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(acc '()))
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(let ((c (ftype-ref unsigned-8 () str i)))
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(if (zero? c)
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(list->string (reverse acc))
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(loop (+ i 1) (cons (integer->char c) acc))))))
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(define (string->cstring str)
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(let* ((len (string-length str))
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(cstr (make-ftype-pointer unsigned-8
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(foreign-alloc (+ 1 len)))))
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(let loop ((i 0))
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(if (= i len)
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(begin
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(ftype-set! unsigned-8 () cstr i 0)
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cstr)
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(ftype-set! unsigned-8 () cstr i (string-ref str i))))))
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;;; FIXME: put a dynamic wind in to ensure the dev list gets freed
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(define (list-devices dm)
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(define list-devs
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(foreign-procedure "dm_list_devices" ((* DMIoctlInterface) (* DevListPtr)) int))
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(let ((pp (make-ftype-pointer DevListPtr
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(foreign-alloc (ftype-sizeof DevListPtr)))))
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(if (zero? (list-devs dm pp))
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(let loop ((dl (ftype-ref DevListPtr () pp))
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(acc '()))
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;(fmt #t "dl: " dl ", acc: " acc)
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(if (ftype-pointer-null? dl)
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acc
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(loop (ftype-ref DevList (next) dl)
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(cons (make-device-details
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(cstring->string (ftype-ref DevList (name) dl))
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(ftype-ref DevList (major) dl)
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(ftype-ref DevList (minor) dl))
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acc))))
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(fail "dm_list_devices ioctl failed"))))
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(define (create-device dm name uuid)
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(define create
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(foreign-procedure "dm_create_device" ((* DMIoctlInterface) string string) int))
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(unless (zero? (create dm name uuid))
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(fail "create-device failed")))
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(define-syntax define-dev-cmd
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(syntax-rules ()
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((_ nm proc)
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(define (nm dm name)
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(define fn
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(foreign-procedure proc ((* DMIoctlInterface) string) int))
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(unless (zero? (fn dm name))
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(fail (string-append proc " failed")))))))
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(define-dev-cmd remove-device "dm_remove_device")
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(define-dev-cmd suspend-device "dm_suspend_device")
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(define-dev-cmd resume-device "dm_resume_device")
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(define-dev-cmd clear-device "dm_clear_device")
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(define-ftype Target
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(struct
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(next (* Target))
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(len unsigned-64)
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(type (* unsigned-8))
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(args (* unsigned-8))))
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(define-ftype TargetPtr (* Target))
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(define-record-type target
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(fields (mutable len) (mutable type) (mutable args)))
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(define (build-c-target next len type args)
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(let ((t (make-ftype-pointer Target
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(foreign-alloc
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(ftype-sizeof Target)))))
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(ftype-set! Target (next) t next)
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(ftype-set! Target (len) t len)
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(ftype-set! Target (type) t (string->cstring type))
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(ftype-set! Target (args) t (string->cstring args))))
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(define (build-c-targets targets)
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(let loop ((t targets)
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(tail (make-ftype-pointer Target 0)))
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(if (null? t)
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tail
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(loop (cdr targets)
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(build-c-target tail (target-len t) (target-type t) (target-args t))))))
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(define (free-c-targets t)
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(let loop ((t t)
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(acc '()))
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(if (ftype-pointer-null? t)
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(map foreign-free acc)
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(loop (ftype-ref Target (next) t) (cons t acc)))))
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;; targets should be dlambdas with 'size, 'type and 'format methods
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(define (load-table dm name targets)
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(define load
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(foreign-procedure "dm_load" ((* DMIoctlInterface) string (* Target)) int))
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(define (dlambda->target t)
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(make-target (t 'size) (t 'type) (t 'format)))
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(let* ((ctargets (build-c-targets (map dlambda->target targets)))
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(r (load dm name ctargets)))
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(free-c-targets ctargets)
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(unless (zero? r)
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(fail "dm_load failed"))))
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)
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