vcl/headless/svpinst.cxx | 27 ++++++++++++++++++---------
vcl/inc/headless/svpinst.hxx | 4 ++--
2 files changed, 20 insertions(+), 11 deletions(-)
New commits:
commit 021bba1b9d9d0e483a76607aaafaf7eb81ff6bed
Author: Stephan Bergmann <sberg...@redhat.com>
Date: Tue May 10 09:47:04 2016 +0200
Avoid non--async-signal-safe functions in child after fork
Posix requires that a process forked from a multi-threaded process only
calls
async-signal-safe functions between fork and exec. This has been observed
to
cause trouble at least in an ASan build, where a forked sub-process (that
wants
to proceed to exec java from getJavaProps,
jvmfwk/plugins/sunmajor/pluginlib/util.cxx) hangs in
__sanitizer::BlockingMutex::Lock from within ASan's operator new
replacement,
from within the SAL_INFO in SvpSalInstance::CloseWakeupPipe, from within the
atfork_child handler established with pthread_atfork. The rest of the
calls in
SvpSalInstance::Create-/CloseWakupPipe appear to be async-signal-safe.
This pthread_atfork handler got introduced with
dbced8e8584b631524dacf607f752ebb734901db "Don't share the wakeup pipe with
child
processes". It is irrelevant when the child process will proceed to call
exec.
And if the child process does not proceed to call exec (which is the
intented
use case why it got added), the above-mentioned Posix requirement makes it
look
unlikely that the child will operate properly (i.e., not call any
async-signal-
safe functions), unless the parent process was single-threaded.
Change-Id: I9ecaf98597b396e0db83fe98fb11a7df7686e1d6
diff --git a/vcl/headless/svpinst.cxx b/vcl/headless/svpinst.cxx
index 5cbcf4a..0305cee 100644
--- a/vcl/headless/svpinst.cxx
+++ b/vcl/headless/svpinst.cxx
@@ -67,8 +67,8 @@ static void atfork_child()
{
if (SvpSalInstance::s_pDefaultInstance != nullptr)
{
- SvpSalInstance::s_pDefaultInstance->CloseWakeupPipe();
- SvpSalInstance::s_pDefaultInstance->CreateWakeupPipe();
+ SvpSalInstance::s_pDefaultInstance->CloseWakeupPipe(false);
+ SvpSalInstance::s_pDefaultInstance->CreateWakeupPipe(false);
}
}
@@ -82,7 +82,7 @@ SvpSalInstance::SvpSalInstance( SalYieldMutex *pMutex ) :
m_nTimeoutMS = 0;
m_pTimeoutFDS[0] = m_pTimeoutFDS[1] = -1;
- CreateWakeupPipe();
+ CreateWakeupPipe(true);
if( s_pDefaultInstance == nullptr )
s_pDefaultInstance = this;
#ifndef ANDROID
@@ -95,29 +95,38 @@ SvpSalInstance::~SvpSalInstance()
if( s_pDefaultInstance == this )
s_pDefaultInstance = nullptr;
- CloseWakeupPipe();
+ CloseWakeupPipe(true);
}
-void SvpSalInstance::CloseWakeupPipe()
+void SvpSalInstance::CloseWakeupPipe(bool log)
{
if (m_pTimeoutFDS[0] != -1)
{
- SAL_INFO("vcl.headless", "CloseWakeupPipe: Closing inherited wakeup
pipe: [" << m_pTimeoutFDS[0] << "," << m_pTimeoutFDS[1] << "]");
+ if (log)
+ {
+ SAL_INFO("vcl.headless", "CloseWakeupPipe: Closing inherited
wakeup pipe: [" << m_pTimeoutFDS[0] << "," << m_pTimeoutFDS[1] << "]");
+ }
close (m_pTimeoutFDS[0]);
close (m_pTimeoutFDS[1]);
m_pTimeoutFDS[0] = m_pTimeoutFDS[1] = -1;
}
}
-void SvpSalInstance::CreateWakeupPipe()
+void SvpSalInstance::CreateWakeupPipe(bool log)
{
if (pipe (m_pTimeoutFDS) == -1)
{
- SAL_WARN("vcl.headless", "Could not create wakeup pipe: " <<
strerror(errno));
+ if (log)
+ {
+ SAL_WARN("vcl.headless", "Could not create wakeup pipe: " <<
strerror(errno));
+ }
}
else
{
- SAL_INFO("vcl.headless", "CreateWakeupPipe: Created wakeup pipe: [" <<
m_pTimeoutFDS[0] << "," << m_pTimeoutFDS[1] << "]");
+ if (log)
+ {
+ SAL_INFO("vcl.headless", "CreateWakeupPipe: Created wakeup pipe:
[" << m_pTimeoutFDS[0] << "," << m_pTimeoutFDS[1] << "]");
+ }
// initialize 'wakeup' pipe.
int flags;
diff --git a/vcl/inc/headless/svpinst.hxx b/vcl/inc/headless/svpinst.hxx
index 76250b1..f39fefd 100644
--- a/vcl/inc/headless/svpinst.hxx
+++ b/vcl/inc/headless/svpinst.hxx
@@ -92,8 +92,8 @@ public:
SvpSalInstance( SalYieldMutex *pMutex );
virtual ~SvpSalInstance();
- void CloseWakeupPipe();
- void CreateWakeupPipe();
+ void CloseWakeupPipe(bool log);
+ void CreateWakeupPipe(bool log);
void PostEvent(const SalFrame* pFrame, ImplSVEvent*
pData, sal_uInt16 nEvent);
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