[haiku-commits] haiku: hrev47384 - src/apps/terminal
- From: ingo_weinhold@xxxxxx
- To: haiku-commits@xxxxxxxxxxxxx
- Date: Mon, 16 Jun 2014 11:09:16 +0200 (CEST)
hrev47384 adds 1 changeset to branch 'master'
old head: 6563b112643871b3a1d35cdf5127f7766b46be8a
new head: eb718e31d22dded84f10f218d3a380ef5707dee1
overview: http://cgit.haiku-os.org/haiku/log/?qt=range&q=eb718e3+%5E6563b11
----------------------------------------------------------------------------
eb718e3: Terminal: Handle SIGCHLD in a dedicated thread
Block SIGCHLD in all threads and spawn a dedicated thread that handles
the signal in a loop (via sigwait()). This avoids the issue that the
SIGCHLD could be handled in any of our threads and thus possibly
interrupt a syscall.
Fixes #10941.
[ Ingo Weinhold <ingo_weinhold@xxxxxx> ]
----------------------------------------------------------------------------
Revision: hrev47384
Commit: eb718e31d22dded84f10f218d3a380ef5707dee1
URL: http://cgit.haiku-os.org/haiku/commit/?id=eb718e3
Author: Ingo Weinhold <ingo_weinhold@xxxxxx>
Date: Mon Jun 16 09:08:02 2014 UTC
Ticket: https://dev.haiku-os.org/ticket/10941
----------------------------------------------------------------------------
2 files changed, 68 insertions(+), 39 deletions(-)
src/apps/terminal/TermApp.cpp | 101 ++++++++++++++++++++++++--------------
src/apps/terminal/TermApp.h | 6 ++-
----------------------------------------------------------------------------
diff --git a/src/apps/terminal/TermApp.cpp b/src/apps/terminal/TermApp.cpp
index 908edc0..bb016af 100644
--- a/src/apps/terminal/TermApp.cpp
+++ b/src/apps/terminal/TermApp.cpp
@@ -56,7 +56,10 @@ main()
#define B_TRANSLATION_CONTEXT "Terminal TermApp"
TermApp::TermApp()
- : BApplication(TERM_SIGNATURE),
+ :
+ BApplication(TERM_SIGNATURE),
+ fChildCleanupThread(-1),
+ fTerminating(false),
fStartFullscreen(false),
fTermWindow(NULL),
fArgs(NULL)
@@ -81,24 +84,39 @@ TermApp::ReadyToRun()
return;
// Install a SIGCHLD signal handler, so that we will be notified, when
- // a shell exits.
+ // a shell exits. The handler itself will never be executed, since we
block
+ // the signal in all threads and handle it with sigwaitinfo() in the
child
+ // cleanup thread.
struct sigaction action;
-#ifdef __HAIKU__
action.sa_handler = (__sighandler_t)_SigChildHandler;
-#else
- action.sa_handler = (__signal_func_ptr)_SigChildHandler;
-#endif
sigemptyset(&action.sa_mask);
-#ifdef SA_NODEFER
- action.sa_flags = SA_NODEFER;
-#endif
- action.sa_userdata = this;
+ action.sa_flags = 0;
if (sigaction(SIGCHLD, &action, NULL) < 0) {
- fprintf(stderr, "sigaction() failed: %s\n",
- strerror(errno));
+ fprintf(stderr, "sigaction() failed: %s\n", strerror(errno));
// continue anyway
}
+ // block SIGCHLD and SIGUSR1 -- we send the latter to wake up the child
+ // cleanup thread when quitting.
+ sigset_t blockedSignals;
+ sigemptyset(&blockedSignals);
+ sigaddset(&blockedSignals, SIGCHLD);
+ sigaddset(&blockedSignals, SIGUSR1);
+
+ int error = pthread_sigmask(SIG_BLOCK, &blockedSignals, NULL);
+ if (error != 0)
+ fprintf(stderr, "pthread_sigmask() failed: %s\n",
strerror(errno));
+
+ // spawn the child cleanup thread
+ fChildCleanupThread = spawn_thread(_ChildCleanupThreadEntry,
+ "child cleanup", B_NORMAL_PRIORITY, this);
+ if (fChildCleanupThread >= 0) {
+ resume_thread(fChildCleanupThread);
+ } else {
+ fprintf(stderr, "Failed to start child cleanup thread: %s\n",
+ strerror(fChildCleanupThread));
+ }
+
// init the mouse copy'n'paste clipboard
gMouseClipboard = new BClipboard(MOUSE_CLIPBOARD_NAME, true);
@@ -145,6 +163,13 @@ TermApp::QuitRequested()
void
TermApp::Quit()
{
+ fTerminating = true;
+
+ if (fChildCleanupThread >= 0) {
+ send_signal(fChildCleanupThread, SIGUSR1);
+ wait_for_thread(fChildCleanupThread, NULL);
+ }
+
BApplication::Quit();
}
@@ -157,10 +182,6 @@ TermApp::MessageReceived(BMessage* message)
fTermWindow->Activate();
break;
- case MSG_CHECK_CHILDREN:
- _HandleChildCleanup();
- break;
-
default:
BApplication::MessageReceived(message);
break;
@@ -264,35 +285,41 @@ TermApp::_MakeTermWindow()
//}
-void
-TermApp::_HandleChildCleanup()
-{
-}
-
-
/*static*/ void
TermApp::_SigChildHandler(int signal, void* data)
{
- // Spawing a thread that does the actual signal handling is pretty much
- // the only safe thing to do in a multi-threaded application. The
- // interrupted thread might have been anywhere, e.g. in a critical
section,
- // holding locks. If we do anything that does require locking at any
point
- // (e.g. memory allocation, messaging), we risk a dead-lock or data
- // structure corruption. Spawing a thread is safe though, since its only
- // a system call.
- thread_id thread = spawn_thread(_ChildCleanupThread, "child cleanup",
- B_NORMAL_PRIORITY, ((TermApp*)data)->fTermWindow);
- if (thread >= 0)
- resume_thread(thread);
+ fprintf(stderr, "Terminal: _SigChildHandler() called! That should never
"
+ "happen!\n");
}
/*static*/ status_t
-TermApp::_ChildCleanupThread(void* data)
+TermApp::_ChildCleanupThreadEntry(void* data)
+{
+ return ((TermApp*)data)->_ChildCleanupThread();
+}
+
+
+status_t
+TermApp::_ChildCleanupThread()
{
- // Just drop the windowa message and let it do the actual work. This
- // saves us additional synchronization measures.
- return ((TermWindow*)data)->PostMessage(MSG_CHECK_CHILDREN);
+ sigset_t waitForSignals;
+ sigemptyset(&waitForSignals);
+ sigaddset(&waitForSignals, SIGCHLD);
+ sigaddset(&waitForSignals, SIGUSR1);
+
+ for (;;) {
+ int signal;
+ int error = sigwait(&waitForSignals, &signal);
+
+ if (fTerminating)
+ break;
+
+ if (error == 0 && signal == SIGCHLD)
+ fTermWindow->PostMessage(MSG_CHECK_CHILDREN);
+ }
+
+ return B_OK;
}
diff --git a/src/apps/terminal/TermApp.h b/src/apps/terminal/TermApp.h
index 45fbd83..1a68c3a 100644
--- a/src/apps/terminal/TermApp.h
+++ b/src/apps/terminal/TermApp.h
@@ -43,13 +43,15 @@ protected:
private:
status_t _MakeTermWindow();
- void _HandleChildCleanup();
static void _SigChildHandler(int signal,
void* data);
- static status_t _ChildCleanupThread(void* data);
+ static status_t _ChildCleanupThreadEntry(void*
data);
+ status_t _ChildCleanupThread();
void _Usage(char *name);
void _InitDefaultPalette();
private:
+ thread_id fChildCleanupThread;
+ bool fTerminating;
bool fStartFullscreen;
BString fWindowTitle;
Other related posts:
