diff options
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | tests/unixForkEvent.test | 45 | ||||
| -rw-r--r-- | unix/tclUnixNotfy.c | 113 |
3 files changed, 163 insertions, 1 deletions
@@ -1,3 +1,9 @@ +2013-08-01 Harald Oehlmann <oehhar@users.sf.net> + + * tclUnixNotify.c Tcl_InitNotifier: Bug [a0bc856dcd] + Start notifier thread again if we were forked, to solve Rivet bug + 55153. + 2013-07-05 Kevin B. Kenny <kennykb@acm.org> * library/tzdata/Africa/Casablanca: diff --git a/tests/unixForkEvent.test b/tests/unixForkEvent.test new file mode 100644 index 0000000..cbe582e --- /dev/null +++ b/tests/unixForkEvent.test @@ -0,0 +1,45 @@ +# This file contains a collection of tests for the procedures in the file +# tclUnixNotify.c. Sourcing this file into Tcl runs the tests and +# generates output for errors. No output means no errors were found. +# +# Copyright (c) 1995-1997 Sun Microsystems, Inc. +# Copyright (c) 1998-1999 by Scriptics Corporation. +# +# See the file "license.terms" for information on usage and redistribution +# of this file, and for a DISCLAIMER OF ALL WARRANTIES. + +package require tcltest 2 +namespace import -force ::tcltest::* + +testConstraint testfork [llength [info commands testfork]] + +# Test if the notifier thread is well initialized in a forked interpreter +# by Tcl_InitNotifier +test unixforkevent-1.1 {fork and test writeable event} \ + -constraints testfork \ + -body { + set myFolder [makeDirectory unixtestfork] + set pid [testfork] + if {$pid == 0} { + # we are the forked process + set result initialized + set h [open [file join $myFolder test.txt] w] + fileevent $h writable\ + "set result writable;\ + after cancel [after 1000 {set result timeout}]" + vwait result + close $h + makeFile $result result.txt $myFolder + exit + } + # we are the original process + while {![file readable [file join $myFolder result.txt]]} {} + viewFile result.txt $myFolder + } \ + -result {writable} \ + -cleanup { + catch { removeFolder $myFolder } + } + +::tcltest::cleanupTests +return diff --git a/unix/tclUnixNotfy.c b/unix/tclUnixNotfy.c index aacc8d2d..c6c9759 100644 --- a/unix/tclUnixNotfy.c +++ b/unix/tclUnixNotfy.c @@ -120,6 +120,15 @@ static Tcl_ThreadDataKey dataKey; static int notifierCount = 0; /* + * The following static stores the process ID of the initialized notifier + * thread. If it changes, we have passed a fork and we should start a new + * notifier thread. + * + * You must hold the notifierMutex lock before accessing this variable. + */ +static pid_t processIDInitialized = 0; + +/* * The following variable points to the head of a doubly-linked list of * ThreadSpecificData structures for all threads that are currently waiting on * an event. @@ -185,7 +194,13 @@ static Tcl_ThreadId notifierThread; #ifdef TCL_THREADS static void NotifierThreadProc(ClientData clientData); -#endif +#ifdef HAVE_PTHREAD_ATFORK +static int atForkInit = 0; +static void AtForkPrepare(void); +static void AtForkParent(void); +static void AtForkChild(void); +#endif /* HAVE_PTHREAD_ATFORK */ +#endif /* TCL_THREADS */ static int FileHandlerEventProc(Tcl_Event *evPtr, int flags); /* @@ -275,11 +290,38 @@ Tcl_InitNotifier(void) */ Tcl_MutexLock(¬ifierMutex); +#ifdef HAVE_PTHREAD_ATFORK + /* + * Install pthread_atfork handlers to reinitialize the notifier in the + * child of a fork. + */ + + if (!atForkInit) { + int result = pthread_atfork(AtForkPrepare, AtForkParent, AtForkChild); + + if (result) { + Tcl_Panic("Tcl_InitNotifier: pthread_atfork failed"); + } + atForkInit = 1; + } +#endif + /* + * Check if my process id changed, e.g. I was forked + * In this case, restart the notifier thread and close the + * pipe to the original notifier thread + */ + if (notifierCount > 0 && processIDInitialized != getpid()) { + notifierCount = 0; + processIDInitialized = 0; + close(triggerPipe); + triggerPipe = -1; + } if (notifierCount == 0) { if (TclpThreadCreate(¬ifierThread, NotifierThreadProc, NULL, TCL_THREAD_STACK_DEFAULT, TCL_THREAD_JOINABLE) != TCL_OK) { Tcl_Panic("Tcl_InitNotifier: unable to start notifier thread"); } + processIDInitialized = getpid(); } notifierCount++; @@ -1270,6 +1312,75 @@ NotifierThreadProc( TclpThreadExit(0); } + +#ifdef HAVE_PTHREAD_ATFORK +/* + *---------------------------------------------------------------------- + * + * AtForkPrepare -- + * + * Lock the notifier in preparation for a fork. + * + * Results: + * None. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +static void +AtForkPrepare(void) +{ +} + +/* + *---------------------------------------------------------------------- + * + * AtForkParent -- + * + * Unlock the notifier in the parent after a fork. + * + * Results: + * None. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +static void +AtForkParent(void) +{ +} + +/* + *---------------------------------------------------------------------- + * + * AtForkChild -- + * + * Unlock and reinstall the notifier in the child after a fork. + * + * Results: + * None. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +static void +AtForkChild(void) +{ + notifierMutex = NULL; + notifierCV = NULL; + Tcl_InitNotifier(); +} +#endif /* HAVE_PTHREAD_ATFORK */ + #endif /* TCL_THREADS */ #endif /* !HAVE_COREFOUNDATION */ |