summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorPeter Bex <peter@more-magic.net>2017-11-18 13:58:13 +0100
committerPeter Bex <peter@more-magic.net>2017-11-18 13:58:13 +0100
commit1adc1af6d9b52ad33f0b773cfdcd64573a2b7b9e (patch)
tree87af9bb2ce76dbd998da736eeaaff5fdf61aed0b
parentdac7e59c6ccd22d36ba4de9c9c6c171c143eb9cc (diff)
downloadscsh-process-1adc1af6d9b52ad33f0b773cfdcd64573a2b7b9e.tar.gz
Run signal handler in a separate thread
This seems to be necessary so that condition-variable-broadcast! works when the signal handler is running in the same thread as the waiting thread.
-rw-r--r--scsh-process.scm35
-rw-r--r--tests/run.scm9
2 files changed, 26 insertions, 18 deletions
diff --git a/scsh-process.scm b/scsh-process.scm
index 1a6c22b..fd7ff3f 100644
--- a/scsh-process.scm
+++ b/scsh-process.scm
@@ -177,21 +177,26 @@
(else (syntax-rules () ((_ val) val))))))
(let ((old-handler (workaround (signal-handler signal/chld))))
(lambda (signal)
- (for-each (lambda (pid)
- (handle-exceptions exn
- ;; User might have waited manually
- (begin (remove-scsh-pending-process! pid) (void))
- (receive (pid ok? status)
- (posix-process-wait pid #t)
- (unless (zero? pid)
- (let ((p (hash-table-ref *scsh-pending-processes* pid)))
- (scsh-process-exit-status-set! p status)
- (scsh-process-ok?-set! p ok?)
- (condition-variable-broadcast!
- (scsh-process-child-condition p))
- ;; The GC can clean it up
- (remove-scsh-pending-process! pid))))))
- (hash-table-keys *scsh-pending-processes*))
+ ;; Run the signal handler in another thread. This is needed
+ ;; because the current thread may be waiting on a condition
+ ;; variable, and we can't wake ourselves up.
+ (thread-start!
+ (lambda ()
+ (for-each (lambda (pid)
+ (handle-exceptions exn
+ ;; User might have waited manually
+ (begin (remove-scsh-pending-process! pid) (void))
+ (receive (pid ok? status)
+ (posix-process-wait pid #t)
+ (unless (zero? pid)
+ (let ((p (hash-table-ref *scsh-pending-processes* pid)))
+ (scsh-process-exit-status-set! p status)
+ (scsh-process-ok?-set! p ok?)
+ (condition-variable-broadcast!
+ (scsh-process-child-condition p))
+ ;; The GC can clean it up
+ (remove-scsh-pending-process! pid))))))
+ (hash-table-keys *scsh-pending-processes*))))
(when old-handler (old-handler signal)))))))
(define (signal-process proc sig)
diff --git a/tests/run.scm b/tests/run.scm
index f05d643..7690752 100644
--- a/tests/run.scm
+++ b/tests/run.scm
@@ -18,9 +18,12 @@
"This is a test"
(run/string* (lambda () (display "This is a test"))))
- ;; We must mask sigchld, because otherwise our (wait #f) will fail
- ;; due to scsh-process' signal handler possibly reaping the child
- ;; before our wait is able to do so.
+ ;; Ensure all processes up to here have been reaped
+ (handle-exceptions exn (void) (let lp () (when (wait #f) (lp))))
+
+ ;; We must mask sigchld, because otherwise our next (wait #f) will
+ ;; fail due to scsh-process' signal handler possibly reaping the
+ ;; child before our wait is able to do so.
(signal-mask! signal/chld)
(test "wait for next process to exit"