X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Ftarget-thread.lisp;h=ed47314e0764e2f28d2c6e51a21b3d2d044455da;hb=bfb7c2d573bacfd9c5f3f243b7c1589f81f11406;hp=639bd2d5992293fb7494c7e75cf6e5407fa40e2f;hpb=3f21f46963f0fecd23d163f1e2d006b169ccf935;p=sbcl.git

diff --git a/src/code/target-thread.lisp b/src/code/target-thread.lisp
index 639bd2d..ed47314 100644
--- a/src/code/target-thread.lisp
+++ b/src/code/target-thread.lisp
@@ -11,6 +11,11 @@
 
 (in-package "SB!THREAD")
 
+;;; Of the WITH-PINNED-OBJECTS in this file, not every single one is
+;;; necessary because threads are only supported with the conservative
+;;; gencgc and numbers on the stack (returned by GET-LISP-OBJ-ADDRESS)
+;;; are treated as references.
+
 ;;; set the doc here because in early-thread FDOCUMENTATION is not
 ;;; available, yet
 #!+sb-doc
@@ -22,7 +27,10 @@
   "Thread type. Do not rely on threads being structs as it may change
 in future versions."
   name
-  %sap)
+  %alive-p
+  os-thread
+  interruptions
+  (interruptions-lock (make-mutex :name "thread interruptions lock")))
 
 #!+sb-doc
 (setf (sb!kernel:fdocumentation 'thread-name 'function)
@@ -38,22 +46,10 @@ in future versions."
         ))
   thread)
 
-(defun thread-state (thread)
-  (let ((state
-         (sb!sys:sap-int
-          (sb!sys:sap-ref-sap (thread-%sap thread)
-                              (* sb!vm::thread-state-slot
-                                 sb!vm::n-word-bytes)))))
-    (ecase state
-      (#.(sb!vm:fixnumize 0) :starting)
-      (#.(sb!vm:fixnumize 1) :running)
-      (#.(sb!vm:fixnumize 2) :suspended)
-      (#.(sb!vm:fixnumize 3) :dead))))
-
 (defun thread-alive-p (thread)
   #!+sb-doc
   "Check if THREAD is running."
-  (not (eq :dead (thread-state thread))))
+  (thread-%alive-p thread))
 
 ;; A thread is eligible for gc iff it has finished and there are no
 ;; more references to it. This list is supposed to keep a reference to
@@ -61,10 +57,18 @@ in future versions."
 (defvar *all-threads* ())
 (defvar *all-threads-lock* (make-mutex :name "all threads lock"))
 
+(defmacro with-all-threads-lock (&body body)
+  #!-sb-thread
+  `(locally ,@body)
+  #!+sb-thread
+  `(without-interrupts
+     (with-mutex (*all-threads-lock*)
+       ,@body)))
+
 (defun list-all-threads ()
   #!+sb-doc
   "Return a list of the live threads."
-  (with-mutex (*all-threads-lock*)
+  (with-all-threads-lock
     (copy-list *all-threads*)))
 
 (declaim (inline current-thread-sap))
@@ -73,12 +77,14 @@ in future versions."
 
 (declaim (inline current-thread-sap-id))
 (defun current-thread-sap-id ()
-  (sb!sys:sap-int
+  (sap-int
    (sb!vm::current-thread-offset-sap sb!vm::thread-os-thread-slot)))
 
 (defun init-initial-thread ()
+  (/show0 "Entering INIT-INITIAL-THREAD")
   (let ((initial-thread (%make-thread :name "initial thread"
-                                      :%sap (current-thread-sap))))
+                                      :%alive-p t
+                                      :os-thread (current-thread-sap-id))))
     (setq *current-thread* initial-thread)
     ;; Either *all-threads* is empty or it contains exactly one thread
     ;; in case we are in reinit since saving core with multiple
@@ -89,45 +95,94 @@ in future versions."
 
 #!+sb-thread
 (progn
+  ;; FIXME it would be good to define what a thread id is or isn't
+  ;; (our current assumption is that it's a fixnum).  It so happens
+  ;; that on Linux it's a pid, but it might not be on posix thread
+  ;; implementations.
   (define-alien-routine ("create_thread" %create-thread)
-      system-area-pointer
-    (lisp-fun-address unsigned-long))
+      unsigned-long (lisp-fun-address unsigned-long))
+
+  (define-alien-routine "signal_interrupt_thread"
+      integer (os-thread unsigned-long))
+
+  (define-alien-routine "block_deferrable_signals"
+      void)
+
+  #!+sb-lutex
+  (progn
+    (declaim (inline %lutex-init %lutex-wait %lutex-wake
+                     %lutex-lock %lutex-unlock))
+
+    (sb!alien:define-alien-routine ("lutex_init" %lutex-init)
+        int (lutex unsigned-long))
+
+    (sb!alien:define-alien-routine ("lutex_wait" %lutex-wait)
+        int (queue-lutex unsigned-long) (mutex-lutex unsigned-long))
+
+    (sb!alien:define-alien-routine ("lutex_wake" %lutex-wake)
+        int (lutex unsigned-long) (n int))
+
+    (sb!alien:define-alien-routine ("lutex_lock" %lutex-lock)
+        int (lutex unsigned-long))
+
+    (sb!alien:define-alien-routine ("lutex_unlock" %lutex-unlock)
+        int (lutex unsigned-long))
 
-  (define-alien-routine "block_deferrable_signals_and_inhibit_gc"
-    void)
+    (sb!alien:define-alien-routine ("lutex_destroy" %lutex-destroy)
+        int (lutex unsigned-long))
 
-  (define-alien-routine reap-dead-thread void
-    (thread-sap system-area-pointer))
+    ;; FIXME: Defining a whole bunch of alien-type machinery just for
+    ;; passing primitive lutex objects directly to foreign functions
+    ;; doesn't seem like fun right now. So instead we just manually
+    ;; pin the lutex, get its address, and let the callee untag it.
+    (defmacro with-lutex-address ((name lutex) &body body)
+      `(let ((,name ,lutex))
+         (with-pinned-objects (,name)
+           (let ((,name (sb!kernel:get-lisp-obj-address ,name)))
+             ,@body))))
 
-  (declaim (inline futex-wait futex-wake))
+    (defun make-lutex ()
+      (/show0 "Entering MAKE-LUTEX")
+      ;; Suppress GC until the lutex has been properly registered with
+      ;; the GC.
+      (without-gcing
+        (let ((lutex (sb!vm::%make-lutex)))
+          (/show0 "LUTEX=..")
+          (/hexstr lutex)
+          (with-lutex-address (lutex lutex)
+            (%lutex-init lutex))
+          lutex))))
 
-  (sb!alien:define-alien-routine "futex_wait"
-      int (word unsigned-long) (old-value unsigned-long))
+  #!-sb-lutex
+  (progn
+    (declaim (inline futex-wait futex-wake))
 
-  (sb!alien:define-alien-routine "futex_wake"
-      int (word unsigned-long) (n unsigned-long)))
+    (sb!alien:define-alien-routine "futex_wait"
+        int (word unsigned-long) (old-value unsigned-long))
+
+    (sb!alien:define-alien-routine "futex_wake"
+        int (word unsigned-long) (n unsigned-long))))
 
 ;;; used by debug-int.lisp to access interrupt contexts
-#!-(and sb-fluid sb-thread) (declaim (inline sb!vm::current-thread-offset-sap))
+#!-(or sb-fluid sb-thread) (declaim (inline sb!vm::current-thread-offset-sap))
 #!-sb-thread
 (defun sb!vm::current-thread-offset-sap (n)
   (declare (type (unsigned-byte 27) n))
-  (sb!sys:sap-ref-sap (alien-sap (extern-alien "all_threads" (* t)))
+  (sap-ref-sap (alien-sap (extern-alien "all_threads" (* t)))
                (* n sb!vm:n-word-bytes)))
 
-;;;; spinlocks
+#!+sb-thread
+(defun sb!vm::current-thread-offset-sap (n)
+  (declare (type (unsigned-byte 27) n))
+  (sb!vm::current-thread-offset-sap n))
 
-(defstruct spinlock
-  #!+sb-doc
-  "Spinlock type."
-  (name nil :type (or null simple-string))
-  (value 0))
+;;;; spinlocks
 
 (declaim (inline get-spinlock release-spinlock))
 
 ;;; The bare 2 here and below are offsets of the slots in the struct.
 ;;; There ought to be some better way to get these numbers
-(defun get-spinlock (spinlock new-value)
+(defun get-spinlock (spinlock)
   (declare (optimize (speed 3) (safety 0))
            #!-sb-thread
            (ignore spinlock new-value))
@@ -135,7 +190,7 @@ in future versions."
   ;; store any value
   #!+sb-thread
   (loop until
-        (eql (sb!vm::%instance-set-conditional spinlock 2 0 new-value) 0)))
+        (eql (sb!vm::%instance-set-conditional spinlock 2 0 1) 0)))
 
 (defun release-spinlock (spinlock)
   (declare (optimize (speed 3) (safety 0))
@@ -150,19 +205,13 @@ in future versions."
 (defmacro with-spinlock ((spinlock) &body body)
   (sb!int:with-unique-names (lock)
     `(let ((,lock ,spinlock))
-      (get-spinlock ,lock *current-thread*)
+      (get-spinlock ,lock)
       (unwind-protect
            (progn ,@body)
         (release-spinlock ,lock)))))
 
 ;;;; mutexes
 
-(defstruct mutex
-  #!+sb-doc
-  "Mutex type."
-  (name nil :type (or null simple-string))
-  (value nil))
-
 #!+sb-doc
 (setf (sb!kernel:fdocumentation 'make-mutex 'function)
       "Create a mutex."
@@ -171,23 +220,25 @@ in future versions."
       (sb!kernel:fdocumentation 'mutex-value 'function)
       "The value of the mutex. NIL if the mutex is free. Setfable.")
 
-#!+sb-thread
-(declaim (inline mutex-value-address))
-#!+sb-thread
-(defun mutex-value-address (mutex)
-  (declare (optimize (speed 3)))
-  (sb!ext:truly-the
-   sb!vm:word
-   (+ (sb!kernel:get-lisp-obj-address mutex)
-      (- (* 3 sb!vm:n-word-bytes) sb!vm:instance-pointer-lowtag))))
-
-(defun get-mutex (mutex &optional new-value (wait-p t))
+#!+(and sb-thread (not sb-lutex))
+(progn
+  (declaim (inline mutex-value-address))
+  (defun mutex-value-address (mutex)
+    (declare (optimize (speed 3)))
+    (sb!ext:truly-the
+     sb!vm:word
+     (+ (sb!kernel:get-lisp-obj-address mutex)
+        (- (* 3 sb!vm:n-word-bytes) sb!vm:instance-pointer-lowtag)))))
+
+(defun get-mutex (mutex &optional (new-value *current-thread*) (wait-p t))
   #!+sb-doc
   "Acquire MUTEX, setting it to NEW-VALUE or some suitable default
 value if NIL.  If WAIT-P is non-NIL and the mutex is in use, sleep
 until it is available"
   (declare (type mutex mutex) (optimize (speed 3)))
-  (unless new-value (setf new-value *current-thread*))
+  (/show0 "Entering GET-MUTEX")
+  (unless new-value
+    (setq new-value *current-thread*))
   #!-sb-thread
   (let ((old-value (mutex-value mutex)))
     (when (and old-value wait-p)
@@ -197,28 +248,44 @@ until it is available"
     (setf (mutex-value mutex) new-value)
     t)
   #!+sb-thread
-  (let (old)
+  (progn
     (when (eql new-value (mutex-value mutex))
       (warn "recursive lock attempt ~S~%" mutex)
       (format *debug-io* "Thread: ~A~%" *current-thread*)
       (sb!debug:backtrace most-positive-fixnum *debug-io*)
       (force-output *debug-io*))
-    (loop
-     (unless
-         (setf old (sb!vm::%instance-set-conditional mutex 2 nil new-value))
-       (return t))
-     (unless wait-p (return nil))
-     (futex-wait (mutex-value-address mutex)
-                 (sb!kernel:get-lisp-obj-address old)))))
+    ;; FIXME: sb-lutex and (not wait-p)
+    #!+sb-lutex
+    (when wait-p
+      (with-lutex-address (lutex (mutex-lutex mutex))
+        (%lutex-lock lutex))
+      (setf (mutex-value mutex) new-value))
+    #!-sb-lutex
+    (let (old)
+      (loop
+         (unless
+             (setf old (sb!vm::%instance-set-conditional mutex 2 nil
+                                                         new-value))
+           (return t))
+         (unless wait-p (return nil))
+         (with-pinned-objects (mutex old)
+           (futex-wait (mutex-value-address mutex)
+                       (sb!kernel:get-lisp-obj-address old)))))))
 
 (defun release-mutex (mutex)
   #!+sb-doc
   "Release MUTEX by setting it to NIL. Wake up threads waiting for
 this mutex."
   (declare (type mutex mutex))
+  (/show0 "Entering RELEASE-MUTEX")
   (setf (mutex-value mutex) nil)
   #!+sb-thread
-  (futex-wake (mutex-value-address mutex) 1))
+  (progn
+    #!+sb-lutex
+    (with-lutex-address (lutex (mutex-lutex mutex))
+      (%lutex-unlock lutex))
+    #!-sb-lutex
+    (futex-wake (mutex-value-address mutex) 1)))
 
 ;;;; waitqueues/condition variables
 
@@ -226,6 +293,9 @@ this mutex."
   #!+sb-doc
   "Waitqueue type."
   (name nil :type (or null simple-string))
+  #!+(and sb-lutex sb-thread)
+  (lutex (make-lutex))
+  #!-sb-lutex
   (data nil))
 
 (defun make-waitqueue (&key name)
@@ -237,15 +307,15 @@ this mutex."
 (setf (sb!kernel:fdocumentation 'waitqueue-name 'function)
       "The name of the waitqueue. Setfable.")
 
-#!+sb-thread
-(declaim (inline waitqueue-data-address))
-#!+sb-thread
-(defun waitqueue-data-address (waitqueue)
-  (declare (optimize (speed 3)))
-  (sb!ext:truly-the
-   sb!vm:word
-   (+ (sb!kernel:get-lisp-obj-address waitqueue)
-      (- (* 3 sb!vm:n-word-bytes) sb!vm:instance-pointer-lowtag))))
+#!+(and sb-thread (not sb-lutex))
+(progn
+  (declaim (inline waitqueue-data-address))
+  (defun waitqueue-data-address (waitqueue)
+    (declare (optimize (speed 3)))
+    (sb!ext:truly-the
+     sb!vm:word
+     (+ (sb!kernel:get-lisp-obj-address waitqueue)
+        (- (* 3 sb!vm:n-word-bytes) sb!vm:instance-pointer-lowtag)))))
 
 (defun condition-wait (queue mutex)
   #!+sb-doc
@@ -257,6 +327,15 @@ time we reacquire MUTEX and return to the caller."
   #!-sb-thread (error "Not supported in unithread builds.")
   #!+sb-thread
   (let ((value (mutex-value mutex)))
+    (/show0 "CONDITION-WAITing")
+    #!+sb-lutex
+    (progn
+      (setf (mutex-value mutex) nil)
+      (with-lutex-address (queue-lutex-address (waitqueue-lutex queue))
+        (with-lutex-address (mutex-lutex-address (mutex-lutex mutex))
+          (%lutex-wait queue-lutex-address mutex-lutex-address)))
+      (setf (mutex-value mutex) value))
+    #!-sb-lutex
     (unwind-protect
          (let ((me *current-thread*))
            ;; XXX we should do something to ensure that the result of this setf
@@ -268,38 +347,86 @@ time we reacquire MUTEX and return to the caller."
            ;; this comment, it will change queue->data, and so
            ;; futex-wait returns immediately instead of sleeping.
            ;; Ergo, no lost wakeup
-           (futex-wait (waitqueue-data-address queue)
-                       (sb!kernel:get-lisp-obj-address me)))
+           (with-pinned-objects (queue me)
+             (futex-wait (waitqueue-data-address queue)
+                         (sb!kernel:get-lisp-obj-address me))))
       ;; If we are interrupted while waiting, we should do these things
       ;; before returning.  Ideally, in the case of an unhandled signal,
       ;; we should do them before entering the debugger, but this is
       ;; better than nothing.
       (get-mutex mutex value))))
 
-(defun condition-notify (queue)
+(defun condition-notify (queue &optional (n 1))
   #!+sb-doc
-  "Notify one of the threads waiting on QUEUE."
-  #!-sb-thread (declare (ignore queue))
+  "Notify N threads waiting on QUEUE."
+  #!-sb-thread (declare (ignore queue n))
   #!-sb-thread (error "Not supported in unithread builds.")
   #!+sb-thread
-  (let ((me *current-thread*))
+  (declare (type (and fixnum (integer 1)) n))
+  (/show0 "Entering CONDITION-NOTIFY")
+  #!+sb-thread
+  (progn
+    #!+sb-lutex
+    (with-lutex-address (lutex (waitqueue-lutex queue))
+      (%lutex-wake lutex n))
     ;; no problem if >1 thread notifies during the comment in
     ;; condition-wait: as long as the value in queue-data isn't the
     ;; waiting thread's id, it matters not what it is
     ;; XXX we should do something to ensure that the result of this setf
     ;; is visible to all CPUs
-    (setf (waitqueue-data queue) me)
-    (futex-wake (waitqueue-data-address queue) 1)))
+    #!-sb-lutex
+    (let ((me *current-thread*))
+      (progn
+        (setf (waitqueue-data queue) me)
+        (with-pinned-objects (queue)
+          (futex-wake (waitqueue-data-address queue) n))))))
 
 (defun condition-broadcast (queue)
   #!+sb-doc
   "Notify all threads waiting on QUEUE."
-  #!-sb-thread (declare (ignore queue))
-  #!-sb-thread (error "Not supported in unithread builds.")
-  #!+sb-thread
-  (let ((me *current-thread*))
-    (setf (waitqueue-data queue) me)
-    (futex-wake (waitqueue-data-address queue) (ash 1 30))))
+  (condition-notify queue
+                    ;; On a 64-bit platform truncating M-P-F to an int results
+                    ;; in -1, which wakes up only one thread.
+                    (ldb (byte 29 0)
+                         most-positive-fixnum)))
+
+;;;; semaphores
+
+(defstruct (semaphore (:constructor %make-semaphore))
+  #!+sb-doc
+  "Semaphore type."
+  (name nil :type (or null simple-string))
+  (count 0 :type (integer 0))
+  (mutex (make-mutex))
+  (queue (make-waitqueue)))
+
+(defun make-semaphore (&key name (count 0))
+  #!+sb-doc
+  "Create a semaphore with the supplied COUNT."
+  (%make-semaphore :name name :count count))
+
+(setf (sb!kernel:fdocumentation 'semaphore-name 'function)
+      "The name of the semaphore. Setfable.")
+
+(defun wait-on-semaphore (sem)
+  #!+sb-doc
+  "Decrement the count of SEM if the count would not be negative. Else
+block until the semaphore can be decremented."
+  ;; a more direct implementation based directly on futexes should be
+  ;; possible
+  (with-mutex ((semaphore-mutex sem))
+    (loop until (> (semaphore-count sem) 0)
+          do (condition-wait (semaphore-queue sem) (semaphore-mutex sem))
+          finally (decf (semaphore-count sem)))))
+
+(defun signal-semaphore (sem &optional (n 1))
+  #!+sb-doc
+  "Increment the count of SEM by N. If there are threads waiting on
+this semaphore, then N of them is woken up."
+  (declare (type (and fixnum (integer 1)) n))
+  (with-mutex ((semaphore-mutex sem))
+    (when (= n (incf (semaphore-count sem) n))
+      (condition-notify (semaphore-queue sem) n))))
 
 ;;;; job control, independent listeners
 
@@ -319,16 +446,18 @@ time we reacquire MUTEX and return to the caller."
   #!-sb-thread
   `(locally ,@body)
   #!+sb-thread
-  `(sb!sys:without-interrupts
-    (with-mutex ((session-lock ,session))
-      ,@body)))
+  `(without-interrupts
+     (with-mutex ((session-lock ,session))
+       ,@body)))
 
 (defun new-session ()
   (make-session :threads (list *current-thread*)
                 :interactive-threads (list *current-thread*)))
 
 (defun init-job-control ()
-  (setf *session* (new-session)))
+  (/show0 "Entering INIT-JOB-CONTROL")
+  (setf *session* (new-session))
+  (/show0 "Exiting INIT-JOB-CONTROL"))
 
 (defun %delete-thread-from-session (thread session)
   (with-session-lock (session)
@@ -351,10 +480,22 @@ time we reacquire MUTEX and return to the caller."
 ;;; Remove thread from its session, if it has one.
 #!+sb-thread
 (defun handle-thread-exit (thread)
-  (with-mutex (*all-threads-lock*)
-    (setq *all-threads* (delete thread *all-threads*)))
-  (when *session*
-    (%delete-thread-from-session thread *session*)))
+  (/show0 "HANDLING THREAD EXIT")
+  ;; We're going down, can't handle interrupts sanely anymore.
+  ;; GC remains enabled.
+  (block-deferrable-signals)
+  ;; Lisp-side cleanup
+  (with-all-threads-lock
+    (setf (thread-%alive-p thread) nil)
+    (setf (thread-os-thread thread) nil)
+    (setq *all-threads* (delete thread *all-threads*))
+    (when *session*
+      (%delete-thread-from-session thread *session*)))
+  #!+sb-lutex
+  (when (thread-interruptions-lock thread)
+    (/show0 "FREEING MUTEX LUTEX")
+    (with-lutex-address (lutex (mutex-lutex (thread-interruptions-lock thread)))
+      (%lutex-destroy lutex))))
 
 (defun terminate-session ()
   #!+sb-doc
@@ -393,6 +534,7 @@ interactive."
   #!+sb-thread
   (let ((was-foreground t))
     (loop
+     (/show0 "Looping in GET-FOREGROUND")
      (with-session-lock (*session*)
        (let ((int-t (session-interactive-threads *session*)))
          (when (eq (car int-t) *current-thread*)
@@ -435,16 +577,16 @@ have the foreground next."
     (labels ((thread-repl ()
                (sb!unix::unix-setsid)
                (let* ((sb!impl::*stdin*
-                       (sb!sys:make-fd-stream in :input t :buffering :line
-                                              :dual-channel-p t))
+                       (make-fd-stream in :input t :buffering :line
+                                       :dual-channel-p t))
                       (sb!impl::*stdout*
-                       (sb!sys:make-fd-stream out :output t :buffering :line
+                       (make-fd-stream out :output t :buffering :line
                                               :dual-channel-p t))
                       (sb!impl::*stderr*
-                       (sb!sys:make-fd-stream err :output t :buffering :line
+                       (make-fd-stream err :output t :buffering :line
                                               :dual-channel-p t))
                       (sb!impl::*tty*
-                       (sb!sys:make-fd-stream err :input t :output t
+                       (make-fd-stream err :input t :output t
                                               :buffering :line
                                               :dual-channel-p t))
                       (sb!impl::*descriptor-handlers* nil))
@@ -464,56 +606,70 @@ returns the thread exits."
   #!-sb-thread (error "Not supported in unithread builds.")
   #!+sb-thread
   (let* ((thread (%make-thread :name name))
-         (setup-p nil)
+         (setup-sem (make-semaphore :name "Thread setup semaphore"))
          (real-function (coerce function 'function))
-         (thread-sap
-          (%create-thread
-           (sb!kernel:get-lisp-obj-address
-            (lambda ()
-              ;; FIXME: use semaphores?
-              (loop until setup-p)
-              ;; in time we'll move some of the binding presently done in C
-              ;; here too
-              (let ((*current-thread* thread)
-                    (sb!kernel::*restart-clusters* nil)
-                    (sb!kernel::*handler-clusters* nil)
-                    (sb!kernel::*condition-restarts* nil)
-                    (sb!impl::*descriptor-handlers* nil)) ; serve-event
-                ;; can't use handling-end-of-the-world, because that flushes
-                ;; output streams, and we don't necessarily have any (or we
-                ;; could be sharing them)
-                (unwind-protect
-                     (catch 'sb!impl::toplevel-catcher
-                       (catch 'sb!impl::%end-of-the-world
-                         (with-simple-restart
-                             (terminate-thread
-                              (format nil "~~@<Terminate this thread (~A)~~@:>"
-                                      *current-thread*))
-                           ;; now that most things have a chance to work
-                           ;; properly without messing up other threads, it's
-                           ;; time to enable signals
+         (initial-function
+          (lambda ()
+            ;; In time we'll move some of the binding presently done in C
+            ;; here too.
+            ;;
+            ;; KLUDGE: Here we have a magic list of variables that are
+            ;; not thread-safe for one reason or another.  As people
+            ;; report problems with the thread safety of certain
+            ;; variables, (e.g. "*print-case* in multiple threads
+            ;; broken", sbcl-devel 2006-07-14), we add a few more
+            ;; bindings here.  The Right Thing is probably some variant
+            ;; of Allegro's *cl-default-special-bindings*, as that is at
+            ;; least accessible to users to secure their own libraries.
+            ;;   --njf, 2006-07-15
+            (let ((*current-thread* thread)
+                  (sb!kernel::*restart-clusters* nil)
+                  (sb!kernel::*handler-clusters* nil)
+                  (sb!kernel::*condition-restarts* nil)
+                  (sb!impl::*step-out* nil)
+                  ;; internal printer variables
+                  (sb!impl::*previous-case* nil)
+                  (sb!impl::*previous-readtable-case* nil)
+                  (sb!impl::*merge-sort-temp-vector* (vector)) ; keep these small!
+                  (sb!impl::*zap-array-data-temp* (vector))    ;
+                  (sb!impl::*internal-symbol-output-fun* nil)
+                  (sb!impl::*descriptor-handlers* nil)) ; serve-event
+              (setf (thread-os-thread thread) (current-thread-sap-id))
+              (with-all-threads-lock
+                (push thread *all-threads*))
+              (with-session-lock (*session*)
+                (push thread (session-threads *session*)))
+              (setf (thread-%alive-p thread) t)
+              (signal-semaphore setup-sem)
+              ;; can't use handling-end-of-the-world, because that flushes
+              ;; output streams, and we don't necessarily have any (or we
+              ;; could be sharing them)
+              (catch 'sb!impl::toplevel-catcher
+                (catch 'sb!impl::%end-of-the-world
+                  (with-simple-restart
+                      (terminate-thread
+                       (format nil
+                               "~~@<Terminate this thread (~A)~~@:>"
+                               *current-thread*))
+                    (unwind-protect
+                         (progn
+                           ;; now that most things have a chance to
+                           ;; work properly without messing up other
+                           ;; threads, it's time to enable signals
                            (sb!unix::reset-signal-mask)
-                           (unwind-protect
-                                (funcall real-function)
-                             ;; we're going down, can't handle
-                             ;; interrupts sanely anymore
-                             (block-deferrable-signals-and-inhibit-gc)))))
-                  ;; and remove what can be the last references to the
-                  ;; thread object
-                  (handle-thread-exit thread)
-                  (setq *current-thread* nil)
-                  0))
-              (values))))))
-    (when (sb!sys:sap= thread-sap (sb!sys:int-sap 0))
-      (error "Can't create a new thread"))
-    (setf (thread-%sap thread) thread-sap)
-    (with-mutex (*all-threads-lock*)
-      (push thread *all-threads*))
-    (with-session-lock (*session*)
-      (push thread (session-threads *session*)))
-    (setq setup-p t)
-    (sb!impl::finalize thread (lambda () (reap-dead-thread thread-sap)))
-    thread))
+                           (funcall real-function))
+                      (handle-thread-exit thread))))))
+            (values))))
+    ;; Keep INITIAL-FUNCTION pinned until the child thread is
+    ;; initialized properly.
+    (with-pinned-objects (initial-function)
+      (let ((os-thread
+             (%create-thread
+              (sb!kernel:get-lisp-obj-address initial-function))))
+        (when (zerop os-thread)
+          (error "Can't create a new thread"))
+        (wait-on-semaphore setup-sem)
+        thread))))
 
 (defun destroy-thread (thread)
   #!+sb-doc
@@ -521,26 +677,44 @@ returns the thread exits."
   (terminate-thread thread))
 
 (define-condition interrupt-thread-error (error)
-  ((thread :reader interrupt-thread-error-thread :initarg :thread)
-   (errno :reader interrupt-thread-error-errno :initarg :errno))
+  ((thread :reader interrupt-thread-error-thread :initarg :thread))
   #!+sb-doc
   (:documentation "Interrupting thread failed.")
   (:report (lambda (c s)
-             (format s "interrupt thread ~A failed (~A: ~A)"
-                     (interrupt-thread-error-thread c)
-                     (interrupt-thread-error-errno c)
-                     (strerror (interrupt-thread-error-errno c))))))
+             (format s "Interrupt thread failed: thread ~A has exited."
+                     (interrupt-thread-error-thread c)))))
 
 #!+sb-doc
 (setf (sb!kernel:fdocumentation 'interrupt-thread-error-thread 'function)
-      "The thread that was not interrupted."
-      (sb!kernel:fdocumentation 'interrupt-thread-error-errno 'function)
-      "The reason why the interruption failed.")
+      "The thread that was not interrupted.")
+
+(defmacro with-interruptions-lock ((thread) &body body)
+  `(without-interrupts
+     (with-mutex ((thread-interruptions-lock ,thread))
+       ,@body)))
 
+;; Called from the signal handler.
+(defun run-interruption ()
+  (in-interruption ()
+    (loop
+       (let ((interruption (with-interruptions-lock (*current-thread*)
+                             (pop (thread-interruptions *current-thread*)))))
+         (if interruption
+             (with-interrupts
+               (funcall interruption))
+             (return))))))
+
+;; The order of interrupt execution is peculiar. If thread A
+;; interrupts thread B with I1, I2 and B for some reason receives I1
+;; when FUN2 is already on the list, then it is FUN2 that gets to run
+;; first. But when FUN2 is run SIG_INTERRUPT_THREAD is enabled again
+;; and I2 hits pretty soon in FUN2 and run FUN1. This is of course
+;; just one scenario, and the order of thread interrupt execution is
+;; undefined.
 (defun interrupt-thread (thread function)
   #!+sb-doc
   "Interrupt the live THREAD and make it run FUNCTION. A moderate
-degree of care is expected for use of interrupt-thread, due to its
+degree of care is expected for use of INTERRUPT-THREAD, due to its
 nature: if you interrupt a thread that was holding important locks
 then do something that turns out to need those locks, you probably
 won't like the effect."
@@ -552,18 +726,14 @@ won't like the effect."
   #!+sb-thread
   (if (eq thread *current-thread*)
       (funcall function)
-      (let ((function (coerce function 'function)))
-        (multiple-value-bind (res err)
-            ;; protect against gcing just when the ub32 address is
-            ;; just ready to be passed to C
-            (sb!sys::with-pinned-objects (function)
-              (sb!unix::syscall ("interrupt_thread"
-                                 system-area-pointer sb!alien:unsigned-long)
-                                thread
-                                (thread-%sap thread)
-                                (sb!kernel:get-lisp-obj-address function)))
-          (unless res
-            (error 'interrupt-thread-error :thread thread :errno err))))))
+      (let ((os-thread (thread-os-thread thread)))
+        (cond ((not os-thread)
+               (error 'interrupt-thread-error :thread thread))
+              (t
+               (with-interruptions-lock (thread)
+                 (push function (thread-interruptions thread)))
+               (when (minusp (signal-interrupt-thread os-thread))
+                 (error 'interrupt-thread-error :thread thread)))))))
 
 (defun terminate-thread (thread)
   #!+sb-doc
@@ -576,11 +746,38 @@ SB-EXT:QUIT - the usual cleanup forms will be evaluated"
 ;;; with an SBCL developer first, or are doing something that you
 ;;; should probably discuss with a professional psychiatrist first
 #!+sb-thread
-(defun symbol-value-in-thread (symbol thread)
-  (let ((thread-sap (thread-%sap thread)))
-    (let* ((index (sb!vm::symbol-tls-index symbol))
-           (tl-val (sb!sys:sap-ref-word thread-sap
-                                        (* sb!vm:n-word-bytes index))))
-      (if (eql tl-val sb!vm::unbound-marker-widetag)
-          (sb!vm::symbol-global-value symbol)
-          (sb!kernel:make-lisp-obj tl-val)))))
+(defun thread-sap-for-id (id)
+  (let ((thread-sap (alien-sap (extern-alien "all_threads" (* t)))))
+    (loop
+     (when (sap= thread-sap (int-sap 0)) (return nil))
+     (let ((os-thread (sap-ref-word thread-sap
+                                    (* sb!vm:n-word-bytes
+                                       sb!vm::thread-os-thread-slot))))
+       (when (= os-thread id) (return thread-sap))
+       (setf thread-sap
+             (sap-ref-sap thread-sap (* sb!vm:n-word-bytes
+                                        sb!vm::thread-next-slot)))))))
+
+#!+sb-thread
+(defun symbol-value-in-thread (symbol thread-sap)
+  (let* ((index (sb!vm::symbol-tls-index symbol))
+         (tl-val (sap-ref-word thread-sap
+                               (* sb!vm:n-word-bytes index))))
+    (if (eql tl-val sb!vm::no-tls-value-marker-widetag)
+        (sb!vm::symbol-global-value symbol)
+        (sb!kernel:make-lisp-obj tl-val))))
+
+(defun sb!vm::locked-symbol-global-value-add (symbol-name delta)
+  (sb!vm::locked-symbol-global-value-add symbol-name delta))
+
+;;; Stepping
+
+(defun thread-stepping ()
+  (sb!kernel:make-lisp-obj
+   (sap-ref-word (current-thread-sap)
+                 (* sb!vm::thread-stepping-slot sb!vm:n-word-bytes))))
+
+(defun (setf thread-stepping) (value)
+  (setf (sap-ref-word (current-thread-sap)
+                      (* sb!vm::thread-stepping-slot sb!vm:n-word-bytes))
+        (sb!kernel:get-lisp-obj-address value)))