+;; Type of the second argument to `getitimer' and
+;; the second and third arguments `setitimer'.
+(define-alien-type nil
+ (struct itimerval
+ (it-interval (struct timeval)) ; timer interval
+ (it-value (struct timeval)))) ; current value
+
+(defconstant ITIMER-REAL 0)
+(defconstant ITIMER-VIRTUAL 1)
+(defconstant ITIMER-PROF 2)
+
+(defun unix-getitimer(which)
+ "Unix-getitimer returns the INTERVAL and VALUE slots of one of
+ three system timers (:real :virtual or :profile). On success,
+ unix-getitimer returns 5 values,
+ T, it-interval-secs, it-interval-usec, it-value-secs, it-value-usec."
+ (declare (type (member :real :virtual :profile) which)
+ (values t
+ (unsigned-byte 29) (mod 1000000)
+ (unsigned-byte 29) (mod 1000000)))
+ (let ((which (ecase which
+ (:real ITIMER-REAL)
+ (:virtual ITIMER-VIRTUAL)
+ (:profile ITIMER-PROF))))
+ (with-alien ((itv (struct itimerval)))
+ (syscall* ("getitimer" int (* (struct itimerval)))
+ (values T
+ (slot (slot itv 'it-interval) 'tv-sec)
+ (slot (slot itv 'it-interval) 'tv-usec)
+ (slot (slot itv 'it-value) 'tv-sec)
+ (slot (slot itv 'it-value) 'tv-usec))
+ which (alien-sap (addr itv))))))
+
+(defun unix-setitimer (which int-secs int-usec val-secs val-usec)
+ " Unix-setitimer sets the INTERVAL and VALUE slots of one of
+ three system timers (:real :virtual or :profile). A SIGALRM signal
+ will be delivered VALUE <seconds+microseconds> from now. INTERVAL,
+ when non-zero, is <seconds+microseconds> to be loaded each time
+ the timer expires. Setting INTERVAL and VALUE to zero disables
+ the timer. See the Unix man page for more details. On success,
+ unix-setitimer returns the old contents of the INTERVAL and VALUE
+ slots as in unix-getitimer."
+ (declare (type (member :real :virtual :profile) which)
+ (type (unsigned-byte 29) int-secs val-secs)
+ (type (integer 0 (1000000)) int-usec val-usec)
+ (values t
+ (unsigned-byte 29) (mod 1000000)
+ (unsigned-byte 29) (mod 1000000)))
+ (let ((which (ecase which
+ (:real ITIMER-REAL)
+ (:virtual ITIMER-VIRTUAL)
+ (:profile ITIMER-PROF))))
+ (with-alien ((itvn (struct itimerval))
+ (itvo (struct itimerval)))
+ (setf (slot (slot itvn 'it-interval) 'tv-sec ) int-secs
+ (slot (slot itvn 'it-interval) 'tv-usec) int-usec
+ (slot (slot itvn 'it-value ) 'tv-sec ) val-secs
+ (slot (slot itvn 'it-value ) 'tv-usec) val-usec)
+ (syscall* ("setitimer" int (* (struct timeval))(* (struct timeval)))
+ (values T
+ (slot (slot itvo 'it-interval) 'tv-sec)
+ (slot (slot itvo 'it-interval) 'tv-usec)
+ (slot (slot itvo 'it-value) 'tv-sec)
+ (slot (slot itvo 'it-value) 'tv-usec))
+ which (alien-sap (addr itvn))(alien-sap (addr itvo))))))
+
+(defmacro sb!ext:with-timeout (expires &body body)
+ "Execute the body, interrupting it with a SIGALRM after at least
+EXPIRES seconds have passed. Uses Unix setitimer(), restoring any
+previous timer after the body has finished executing"
+ (with-unique-names (saved-seconds saved-useconds s u)
+ `(let (- ,saved-seconds ,saved-useconds)
+ (multiple-value-setq (- - - ,saved-seconds ,saved-useconds)
+ (unix-getitimer :real))
+ (multiple-value-bind (,s ,u) (floor ,expires)
+ (setf ,u (floor (* ,u 1000000)))
+ (if (and (> ,expires 0)
+ (or (and (zerop ,saved-seconds) (zerop ,saved-useconds))
+ (> ,saved-seconds ,s)
+ (and (= ,saved-seconds ,s)
+ (> ,saved-useconds ,u))))
+ (unwind-protect
+ (progn
+ (unix-setitimer :real 0 0 ,s ,u)
+ ,@body)
+ (unix-setitimer :real 0 0 ,saved-seconds ,saved-useconds))
+ (progn
+ ,@body))))))
+\f