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authorThiago Macieira <[email protected]>2012-09-11 15:36:54 +0200
committerThe Qt Project <[email protected]>2012-09-18 14:11:53 +0200
commit3f970c20f9afd5c9a1cc14d7f69882e13f6aaf1b (patch)
tree7e13275cafbfb8b10190571317ebd76d8191582e /src/network/socket/qnativesocketengine_unix.cpp
parent849f1f9efda601bcfd3760256205a2014e0bc936 (diff)
Fix thread-safety of qt_ignore_sigpipe
The testAndSet operation would mean another thread could see the value of 1 and proceed to write(2)/sendto(2) before SIGPIPE had been ignored. If the pipe or socket were already closed by then, a SIGPIPE would be delivered to the application with its default action: terminate. Change-Id: I62dc8f5fa14c1dd453d13e4053c642bd78fbc468 Reviewed-by: Qt Doc Bot <[email protected]> Reviewed-by: Oswald Buddenhagen <[email protected]> Reviewed-by: Shane Kearns <[email protected]> Reviewed-by: Peter Hartmann <[email protected]>
Diffstat (limited to 'src/network/socket/qnativesocketengine_unix.cpp')
-rw-r--r--src/network/socket/qnativesocketengine_unix.cpp6
1 files changed, 5 insertions, 1 deletions
diff --git a/src/network/socket/qnativesocketengine_unix.cpp b/src/network/socket/qnativesocketengine_unix.cpp
index 4b22f1c262e..c73bbed088f 100644
--- a/src/network/socket/qnativesocketengine_unix.cpp
+++ b/src/network/socket/qnativesocketengine_unix.cpp
@@ -103,11 +103,15 @@ static void qt_ignore_sigpipe()
#ifndef Q_NO_POSIX_SIGNALS
// Set to ignore SIGPIPE once only.
static QBasicAtomicInt atom = Q_BASIC_ATOMIC_INITIALIZER(0);
- if (atom.testAndSetRelaxed(0, 1)) {
+ if (!atom.load()) {
+ // More than one thread could turn off SIGPIPE at the same time
+ // But that's acceptable because they all would be doing the same
+ // action
struct sigaction noaction;
memset(&noaction, 0, sizeof(noaction));
noaction.sa_handler = SIG_IGN;
::sigaction(SIGPIPE, &noaction, 0);
+ atom.store(1);
}
#else
// Posix signals are not supported by the underlying platform