Deadlock-free resource locking.
This commit is contained in:
mainzelm
parent
f456608175
commit
d30130ab03
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@ -53,8 +53,9 @@
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;;; raising an error here won't work due to S48's
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;;; broken exception system
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(else (list err syscall fname)))))
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(with-cwd-aligned
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(with-umask-aligned
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(with-resources-aligned
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(list cwd-resource umask-resource)
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(lambda ()
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(makeit fname)))
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#f))))
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(if (list? result)
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@ -114,5 +115,7 @@
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(and override?
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(y-or-n? (string-append "rename-file:" new-fname
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" already exists. Delete"))))
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(with-cwd-aligned
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(%rename-file old-fname new-fname)))))
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(with-resources-aligned
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(list cwd-resource)
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(lambda ()
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(%rename-file old-fname new-fname))))))
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@ -341,12 +341,13 @@
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(define-interface scsh-process-state-interface
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(export umask
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(export with-resources-aligned
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umask
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set-umask
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with-umask*
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(with-umask :syntax)
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with-umask-aligned*
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(with-umask-aligned :syntax)
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umask-resource
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process-chdir
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process-cwd
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@ -354,8 +355,7 @@
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cwd
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with-cwd*
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(with-cwd :syntax)
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with-cwd-aligned*
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(with-cwd-aligned :syntax)
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cwd-resource
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pid
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parent-pid
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@ -429,7 +429,8 @@
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(with-env :syntax)
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(with-total-env :syntax)
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add-before
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add-after))
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add-after
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environ-resource))
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(define-interface scsh-home-interface
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@ -590,9 +591,9 @@
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(define-interface scsh-utilities-interface
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(export del delete filter first first? nth
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fold fold-right
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any every
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(export del first? filter fold-right
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fold
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any every nth
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mapv mapv! vector-every? copy-vector initialize-vector vector-append
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vfold vfold-right
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check-arg conjoin disjoin negate compose reverse! call/cc
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@ -600,7 +601,8 @@
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deposit-bit-field
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real->exact-integer
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make-reinitializer
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run-as-long-as))
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run-as-long-as
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obtain-all-or-none))
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(define-interface weak-tables-interface
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(export make-weak-table weak-table-set! weak-table-ref weak-table-walk
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@ -35,7 +35,7 @@
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(define-structure scsh-utilities scsh-utilities-interface
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(open bitwise error-package loopholes let-opt scheme define-record-types
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records
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threads threads-internal placeholders)
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threads threads-internal placeholders locks srfi-1)
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(files utilities)
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; (optimize auto-integrate)
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)
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@ -333,7 +333,7 @@
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(define-structure field-reader-package scsh-field-reader-interface
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(open receiving ; receive
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scsh-utilities ; nth
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scsh-utilities ; deprecated-proc
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error-package ; error
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string-lib ; string-join for obsolete join-strings
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scsh-level-0 ; delimited readers
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304
scsh/scsh.scm
304
scsh/scsh.scm
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@ -129,132 +129,228 @@
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(release-lock lock))))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;; working directory per thread
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(define *cwd-cache* 'uninitialized)
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(define cwd-lock (make-lock))
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;;; A resource is a part of the process state for which every thread
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;;; has its own value
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;;; uses the procedures:
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;;; (process-read-resource (-> 'X))
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;;; (process-set-resource ('X -> unspec))
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;;; (resource-eq? ('X 'X -> bool))
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;;; defines the procedures:
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;;; (initialize-resource (-> unspec)) ; call on startup
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;;; (with-resource* ((-> 'X) -> 'X))
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;;; (with-resource-aligned* ((-> 'X) -> 'X))
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;;; (thread-read-resource (-> 'X))
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;;; (thread-set-resource ('X -> unspec))
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(define-syntax make-process-resource
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(syntax-rules
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()
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((make-process-resource
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initialize-resource
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thread-read-resource thread-set-resource! thread-change-resource
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with-resource* with-resource-aligned*
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process-read-resource process-set-resource resource-eq?)
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(begin
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(define *resource-cache* 'uninitialized)
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(define resource-lock 'uninitialized)
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(define (initialize-resource)
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(set! *resource-cache* (process-read-resource))
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(set! $resource ;;; TODO The old thread-fluid will remain
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(define (initialize-cwd)
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(set! *cwd-cache* (process-cwd))
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(set! $cwd ;;; TODO The old thread-fluid will remain
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(make-preserved-thread-fluid
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(process-read-resource)))
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(set! resource-lock (make-lock)))
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(cwd-cache))))
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; (set! cwd-lock (make-lock)))
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(define (cache-value)
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*resource-cache*)
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(define (cwd-cache)
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*cwd-cache*)
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;; Actually do the syscall and update the cache
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;; assumes the resource lock obtained
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(define (change-and-cache res)
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(process-set-resource res)
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(set! *resource-cache* (process-read-resource)))
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;; assumes the cwd lock obtained
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(define (change-and-cache-cwd new-cwd)
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(if (not (file-name-absolute? new-cwd))
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(process-chdir (string-append (cwd) "/" new-cwd))
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(process-chdir new-cwd))
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(set! *cwd-cache* (process-cwd)))
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;; The thread-specific resource: A thread fluid
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;; The thread-specific cwd: A thread fluid
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(define $resource 'empty-resource-value)
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(define $cwd 'empty-cwd-value)
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(define (thread-read-resource) (thread-fluid $resource))
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(define (thread-set-resource! res) (set-thread-fluid! $resource res))
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(define (let-resource res thunk)
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(let-thread-fluid $resource res thunk))
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(define (cwd) (thread-fluid $cwd))
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(define (thread-set-cwd! cwd) (set-thread-fluid! $cwd cwd))
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(define (let-cwd cwd thunk)
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(let-thread-fluid $cwd cwd thunk))
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(define (with-resource* res thunk)
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(let ((changed-res #f))
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(with-lock resource-lock
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(define (with-cwd* new-cwd thunk)
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(let ((changed-cwd
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(with-lock cwd-lock
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(lambda ()
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(align-resource!)
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(change-and-cache res)
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(set! changed-res (cache-value))))
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(let-resource changed-res thunk)))
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(change-and-cache-cwd new-cwd)
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(cwd-cache)))))
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(let-cwd changed-cwd thunk)))
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;; Align the value of the Unix resource with scsh's value.
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;; Align the value of the Unix cwd with scsh's value.
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;; Since another thread could disalign, this call and
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;; any ensuring syscall that relies upon it should
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;; be "glued together" with the resource lock.
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;; be "glued together" with the cwd lock.
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(define (align-resource!)
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(let ((res (thread-read-resource)))
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(if (not (resource-eq? res (cache-value)))
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(change-and-cache res))))
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(define (align-cwd!)
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(let ((thread-cwd (cwd)))
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(if (not (string=? thread-cwd (cwd-cache)))
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(change-and-cache-cwd thread-cwd))))
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(define (thread-change-resource res)
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(with-lock resource-lock
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(define (chdir cwd)
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(with-lock cwd-lock
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(lambda ()
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(align-resource!)
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(change-and-cache res)
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(thread-set-resource! (cache-value)))))
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(change-and-cache-cwd cwd)
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(thread-set-cwd! (cwd-cache)))))
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(define (with-resource-aligned* thunk)
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(obtain-lock resource-lock)
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(align-resource!)
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(with-handler
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(define-record-type resource :resource
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(make-resource align! lock)
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resource?
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(align! resource-align!)
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(lock resource-lock))
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(define (with-resources-aligned resources thunk)
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(let ((locks (map resource-lock resources)))
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(apply obtain-all-or-none locks)
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(for-each
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(lambda (align!) (align!))
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(map resource-align! resources))
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(let ((val (with-handler
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(lambda (cond more)
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(release-lock resource-lock)
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(for-each release-lock locks)
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(more))
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(lambda ()
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(let ((ret (thunk)))
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(release-lock resource-lock)
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ret))))
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thunk)))
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(for-each release-lock locks)
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val)))
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(define cwd-resource (make-resource align-cwd! cwd-lock))
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;; example syscall
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;; (define (exported-delete-file fname)
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;; (with-cwd-aligned (really-delete-file fname)))
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(define resource-reinitializer
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(make-reinitializer (lambda () (warn "calling resumer") (initialize-resource))))))))
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(define cwd-reinitializer
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(make-reinitializer (lambda () (warn "calling resumer") (initialize-cwd))))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;; working directory per thread
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(make-process-resource
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initialize-cwd cwd thread-set-cwd! chdir with-cwd* with-cwd-aligned*
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process-cwd process-chdir string=?)
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(initialize-cwd)
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;; umask per thread
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(define *umask-cache* 'uninitialized)
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(define umask-lock (make-lock))
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(define (initialize-umask)
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(set! *umask-cache* (process-umask))
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(set! $umask ;;; TODO The old thread-fluid will remain
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(make-preserved-thread-fluid
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(umask-cache))))
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; (set! umask-lock (make-lock)))
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(define (umask-cache)
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*umask-cache*)
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;; Actually do the syscall and update the cache
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;; assumes the resource lock obtained
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(define (change-and-cache-umask new-umask)
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(set-process-umask new-umask)
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(set! *umask-cache* (process-umask)))
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;; The thread-specific umask: A thread fluid
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(define $umask 'empty-umask-value)
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(define (umask) (thread-fluid $umask))
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(define (thread-set-umask! new-umask) (set-thread-fluid! $umask new-umask))
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(define (let-umask new-umask thunk)
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(let-thread-fluid $umask new-umask thunk))
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(define (with-umask* new-umask thunk)
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(let ((changed-umask
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(with-lock umask-lock
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(lambda ()
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(change-and-cache-umask new-umask)
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(umask-cache)))))
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(let-umask changed-umask thunk)))
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;; Align the value of the Unix umask with scsh's value.
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;; Since another thread could disalign, this call and
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;; any ensuring syscall that relies upon it should
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;; be "glued together" with the umask lock.
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(define (align-umask!)
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(let ((thread-umask (umask)))
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(if (not (= thread-umask (umask-cache)))
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(change-and-cache-umask thread-umask))))
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(define (set-umask new-umask)
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(with-lock umask-lock
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(lambda ()
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(change-and-cache-umask new-umask)
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(thread-set-umask! (umask-cache)))))
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(define umask-resource (make-resource align-umask! umask-lock))
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;; example syscall
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;; (define (exported-delete-file fname)
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;; (with-cwd-aligned (really-delete-file fname)))
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(define umask-reinitializer
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(make-reinitializer (lambda () (warn "calling resumer") (initialize-umask))))
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(make-process-resource
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initialize-umask umask thread-set-umask set-umask
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with-umask* with-umask-aligned*
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process-umask set-process-umask =)
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(initialize-umask)
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(set-with-fs-context-aligned*! ; ensure S48 is aligned too
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;; ensure S48 is aligned too
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(set-with-fs-context-aligned*!
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(lambda (thunk)
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(with-cwd-aligned*
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(lambda ()
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(with-umask-aligned*
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thunk)))))
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(with-resources-aligned (list cwd-resource umask-resource) thunk)))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;; Environment per thread
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(define *env-cache* 'uninitialized)
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(define env-lock (make-lock))
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(define (install-env)
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(set! *env-cache* (environ**-read))
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(set! $env ;;; TODO The old thread-fluid will remain
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(make-preserved-thread-fluid
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(env-cache))))
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; (set! env-lock (make-lock)))
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(define (env-cache)
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*env-cache*)
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;; Actually do the syscall and update the cache
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;; assumes the env lock obtained
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(define (change-and-cache-env env)
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(environ**-set env)
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(set! *env-cache* env))
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;; The thread-specific env: A thread fluid
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(define $env 'empty-env-value)
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(define (thread-read-env) (thread-fluid $env))
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(define (thread-set-env! res) (set-thread-fluid! $env res))
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(define (let-env res thunk)
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(let-thread-fluid $env res thunk))
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(define (really-with-env* env thunk)
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(with-lock env-lock
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(lambda ()
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(change-and-cache-env env)))
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(let-env env thunk))
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;; Align the value of the Unix env with scsh's value.
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;; Since another thread could disalign, this call and
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;; any ensuring syscall that relies upon it should
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;; be "glued together" with the env lock.
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(define (align-env!)
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(let ((res (thread-read-env)))
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(if (not (env=? res (env-cache)))
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(change-and-cache-env res))))
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(define (thread-change-env res)
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(with-lock env-lock
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(lambda ()
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(change-and-cache-env res)
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(thread-set-env! (env-cache)))))
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(define environ-resource (make-resource align-env! env-lock))
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;; example syscall
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;; (define (exported-delete-file fname)
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;; (with-cwd-aligned (really-delete-file fname)))
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(define env-reinitializer
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(make-reinitializer (lambda () (warn "calling resumer") (install-env))))
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(define-record env
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envvec
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@ -328,12 +424,8 @@
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(with-total-env* new-env thunk)))
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(define (with-total-env* alist thunk)
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(with-env-internal* (make-env #f alist) thunk))
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(really-with-env* (make-env #f alist) thunk))
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(make-process-resource install-env thread-read-env thread-set-env!
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useless-set-env
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with-env-internal* with-env-aligned*
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environ**-read environ**-set env=?)
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;;; These two functions are obsoleted by the more general INFIX-SPLITTER and
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;;; JOIN-STRINGS functions. However, we keep SPLIT-COLON-LIST defined
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@ -418,12 +510,6 @@
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(define-simple-syntax (with-cwd dir . body)
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(with-cwd* dir (lambda () . body)))
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(define-simple-syntax (with-cwd-aligned body ...)
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(with-cwd-aligned* (lambda () body ...)))
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(define-simple-syntax (with-umask-aligned body ...)
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(with-umask-aligned* (lambda () body ...)))
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(define-simple-syntax (with-umask mask . body)
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(with-umask* mask (lambda () . body)))
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|
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@ -487,7 +573,7 @@
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(let ((fname (format #f template (number->string i))))
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(receive retvals (with-errno-handler
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((errno data)
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((errno/exist) #f))
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((errno/exist errno/acces) #f))
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(maker fname))
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(if (car retvals) (apply values retvals)
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(loop (+ i 1)))))))))
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|
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@ -855,13 +941,9 @@
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(define (exec/env prog env . arglist)
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(flush-all-ports)
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(with-env-aligned*
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(with-resources-aligned (list environ-resource cwd-resource umask-resource)
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(lambda ()
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(with-cwd-aligned*
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(lambda ()
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(with-umask-aligned*
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(lambda ()
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(%exec prog (cons prog arglist) env))))))))
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(%exec prog (cons prog arglist) env))))
|
||||
|
||||
;(define (exec-path/env prog env . arglist)
|
||||
; (cond ((exec-path-search (stringify prog) (fluid exec-path-list)) =>
|
||||
|
|
@ -875,11 +957,8 @@
|
|||
|
||||
(define (exec-path/env prog env . arglist)
|
||||
(flush-all-ports)
|
||||
(with-env-aligned*
|
||||
(lambda ()
|
||||
(with-cwd-aligned*
|
||||
(lambda ()
|
||||
(with-umask-aligned*
|
||||
(with-resources-aligned
|
||||
(list environ-resource cwd-resource umask-resource)
|
||||
(lambda ()
|
||||
(let ((prog (stringify prog)))
|
||||
(if (string-index prog #\/)
|
||||
|
|
@ -894,7 +973,7 @@
|
|||
(%%exec binary argv env)))
|
||||
(thread-fluid exec-path-list)))))
|
||||
|
||||
(error "No executable found." prog arglist))))))))
|
||||
(error "No executable found." prog arglist))))
|
||||
|
||||
(define (exec-path prog . arglist)
|
||||
(apply exec-path/env prog #t arglist))
|
||||
|
|
@ -958,7 +1037,8 @@
|
|||
;; with-env-aligned is not neccessary here but it will
|
||||
;; create the environ object in the parent process which
|
||||
;; could reuse it on further forks
|
||||
(let ((pid (with-env-aligned*
|
||||
(let ((pid (with-resources-aligned
|
||||
(list environ-resource)
|
||||
%%fork)))
|
||||
(if (zero? pid)
|
||||
;; Child
|
||||
|
|
|
|||
|
|
@ -183,7 +183,8 @@
|
|||
;;; ports.
|
||||
|
||||
(define (generic-file-op thing fd-op fname-op)
|
||||
(if (string? thing) (with-cwd-aligned (fname-op thing))
|
||||
(if (string? thing)
|
||||
(with-resources-aligned (list cwd-resource) (lambda () (fname-op thing)))
|
||||
(call/fdes thing fd-op)))
|
||||
|
||||
|
||||
|
|
@ -340,7 +341,7 @@
|
|||
(import-os-error-syscall %delete-file (path) "scsh_unlink")
|
||||
|
||||
(define (delete-file path)
|
||||
(with-cwd-aligned (%delete-file path)))
|
||||
(with-resources-aligned (list cwd-resource) (lambda () (%delete-file path))))
|
||||
|
||||
(import-os-error-syscall %sync-file (fd) "scsh_fsync")
|
||||
|
||||
|
|
@ -382,8 +383,9 @@
|
|||
(import-os-error-syscall %open (path flags mode) "scsh_open")
|
||||
|
||||
(define (open-fdes path flags . maybe-mode) ; mode defaults to 0666
|
||||
(with-cwd-aligned
|
||||
(with-umask-aligned
|
||||
(with-resources-aligned
|
||||
(list cwd-resource umask-resource)
|
||||
(lambda ()
|
||||
(%open path flags (:optional maybe-mode #o666)))))
|
||||
|
||||
|
||||
|
|
@ -532,7 +534,9 @@
|
|||
(import-os-error-syscall %open-dir (dir-name) "open_dir")
|
||||
|
||||
(define (directory-files . args)
|
||||
(with-cwd-aligned
|
||||
(with-resources-aligned
|
||||
(list cwd-resource)
|
||||
(lambda ()
|
||||
(let-optionals args ((dir ".")
|
||||
(dotfiles? #f))
|
||||
(check-arg string? dir directory-files)
|
||||
|
|
@ -540,7 +544,7 @@
|
|||
(files-sorted ((structure-ref sort sort-list!) files filename<=)))
|
||||
(if dotfiles? files-sorted
|
||||
(filter (lambda (f) (not (dotfile? f)))
|
||||
files-sorted))))))
|
||||
files-sorted)))))))
|
||||
|
||||
(define (dotfile? f)
|
||||
(char=? (string-ref f 0) #\.))
|
||||
|
|
|
|||
|
|
@ -13,9 +13,6 @@
|
|||
'()))))
|
||||
(del lis)))
|
||||
|
||||
(define (delete pred lis)
|
||||
(filter (lambda (x) (not (pred x))) lis))
|
||||
|
||||
(define (index str c . maybe-start)
|
||||
(let ((start (max 0 (:optional maybe-start 0)))
|
||||
(len (string-length str)))
|
||||
|
|
@ -33,50 +30,6 @@
|
|||
(char=? c (string-ref str i)))
|
||||
(and (>= i 0) i)))))
|
||||
|
||||
;;; (f (f (f zero x1) x2) x3)
|
||||
;;; [Richard's does (f x3 (f x2 (f x1 zero)))
|
||||
(define (reduce f zero l)
|
||||
(letrec ((lp (lambda (val rest)
|
||||
(if (pair? rest) (lp (f val (car rest)) (cdr rest))
|
||||
val))))
|
||||
(lp zero l)))
|
||||
|
||||
(define (fold kons knil lis)
|
||||
(let lp ((lis lis) (ans knil))
|
||||
(if (pair? lis)
|
||||
(lp (cdr lis) (kons (car lis) ans))
|
||||
ans)))
|
||||
|
||||
(define (fold-right kons knil lis)
|
||||
(let recur ((lis lis))
|
||||
(if (pair? lis)
|
||||
(let ((head (car lis))) ; Won't need LIS after RECUR call.
|
||||
(kons head (recur (cdr lis))))
|
||||
knil)))
|
||||
|
||||
(define (filter pred list)
|
||||
(letrec ((filter (lambda (list)
|
||||
(if (pair? list)
|
||||
(let* ((head (car list))
|
||||
(tail (cdr list))
|
||||
(new-tail (filter tail)))
|
||||
(if (pred head)
|
||||
(if (eq? tail new-tail) list
|
||||
(cons head new-tail))
|
||||
new-tail))
|
||||
'()))))
|
||||
(filter list)))
|
||||
|
||||
(define (first pred list)
|
||||
(letrec ((lp (lambda (list)
|
||||
(and (pair? list)
|
||||
(let ((head (car list)))
|
||||
(if (pred head) head
|
||||
(lp (cdr list))))))))
|
||||
(lp list)))
|
||||
|
||||
(define any first)
|
||||
|
||||
;;; Returns the first true value produced by PRED, not the list element
|
||||
;;; that satisfied PRED.
|
||||
|
||||
|
|
@ -89,15 +42,6 @@
|
|||
|
||||
(define any? first?)
|
||||
|
||||
|
||||
(define (every pred list)
|
||||
(or (not (pair? list))
|
||||
(let lp ((head (car list)) (tail (cdr list)))
|
||||
(if (pair? tail)
|
||||
(and (pred head) (lp (car tail) (cdr tail)))
|
||||
(pred head))))) ; Tail-call the last PRED call.
|
||||
|
||||
|
||||
(define (every? pred list)
|
||||
(letrec ((lp (lambda (list)
|
||||
(or (not (pair? list))
|
||||
|
|
@ -291,6 +235,16 @@
|
|||
(kill-thread! thread)
|
||||
(make-ready thread))
|
||||
|
||||
|
||||
(define (obtain-all-or-none . locks)
|
||||
(let lp ((obtained '()) (needed locks))
|
||||
(if (not (null? needed))
|
||||
(let ((next (car needed)))
|
||||
(if (maybe-obtain-lock next)
|
||||
(lp (cons next obtained)
|
||||
(cdr needed))
|
||||
(begin
|
||||
(for-each release-lock obtained)
|
||||
(obtain-lock next)
|
||||
(lp (list next) (delete next locks eq?))))))))
|
||||
|
||||
|
||||
Loading…
Reference in New Issue