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omrsignal.c
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omrsignal.c
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/*******************************************************************************
* Copyright (c) 1991, 2021 IBM Corp. and others
*
* This program and the accompanying materials are made available under
* the terms of the Eclipse Public License 2.0 which accompanies this
* distribution and is available at https://www.eclipse.org/legal/epl-2.0/
* or the Apache License, Version 2.0 which accompanies this distribution and
* is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* This Source Code may also be made available under the following
* Secondary Licenses when the conditions for such availability set
* forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
* General Public License, version 2 with the GNU Classpath
* Exception [1] and GNU General Public License, version 2 with the
* OpenJDK Assembly Exception [2].
*
* [1] https://www.gnu.org/software/classpath/license.html
* [2] http://openjdk.java.net/legal/assembly-exception.html
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
*******************************************************************************/
/**
* @file
* @ingroup Port
* @brief Signal handling
*/
#include "omrcfg.h"
#include "omrport.h"
#include "omrutil.h"
#include "omrutilbase.h"
#include "omrportpriv.h"
#include "ut_omrport.h"
#include "omrthread.h"
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <setjmp.h>
#include <errno.h>
#include "omrsignal_context.h"
#if !defined(J9ZOS390)
#if defined(J9OS_I5) && defined(J9OS_I5_V5R4)
#include "semaphore_i5.h"
#else /* defined(J9OS_I5) && defined(J9OS_I5_V5R4) */
#include <semaphore.h>
#endif /* defined(J9OS_I5) && defined(J9OS_I5_V5R4) */
#endif /* !defined(J9ZOS390) */
#if defined(J9ZOS390)
#include <pthread.h>
#endif /* defined(J9ZOS390) */
#if defined(J9ZOS390)
#if defined(OMR_ENV_DATA64)
#include <__le_api.h>
#else /* defined(OMR_ENV_DATA64) */
#include <leawi.h>
#include <ceeedcct.h>
#endif /* defined(OMR_ENV_DATA64) */
#if defined(OMR_PORT_ZOS_CEEHDLRSUPPORT)
#include "omrsignal_ceehdlr.h"
#endif /* defined(OMR_PORT_ZOS_CEEHDLRSUPPORT) */
#endif /* defined(J9ZOS390) */
#if defined(OMRPORT_OMRSIG_SUPPORT)
#include "omrsig.h"
#endif /* defined(OMRPORT_OMRSIG_SUPPORT) */
#if defined(S390) && defined(LINUX)
typedef void (*unix_sigaction)(int, siginfo_t *, void *, uintptr_t);
#else /* defined(S390) && defined(LINUX) */
typedef void (*unix_sigaction)(int, siginfo_t *, void *);
#endif /* defined(S390) && defined(LINUX) */
#define ARRAY_SIZE_SIGNALS (MAX_UNIX_SIGNAL_TYPES + 1)
/* Keep track of signal counts. */
static volatile uintptr_t signalCounts[ARRAY_SIZE_SIGNALS] = {0};
/* Store the previous signal handlers. We need to restore them during shutdown. */
static struct {
struct sigaction action;
uint32_t restore;
} oldActions[ARRAY_SIZE_SIGNALS];
/* Records the (port library defined) signals for which a handler is registered.
* Access to these variables must be protected by the registerHandlerMonitor.
*
* syncSignalsWithHandlers represents if handlers are registered with synchronous
* signals, and asyncSignalsWithHandlers represents if handlers are registered with
* asynchronous signals.
*/
static uint32_t syncSignalsWithHandlers;
static uint32_t asyncSignalsWithHandlers;
/* Records the (port library defined) signals for which a main handler is
* registered. A main handler can be either mainSynchSignalHandler or
* mainASynchSignalHandler. A signal can only be associated to one main
* handler. If a main handler is already registered for a signal, then avoid
* re-registering a main handler for that signal. Access to these variables
* must be protected by the registerHandlerMonitor.
*
* syncSignalsWithMainHandlers represents if the synchronous main handler is
* registered with synchronous signals, and asyncSignalsWithMainHandlers
* represents if the asynchronous main handler is registered with asynchronous
* signals.
*/
static uint32_t syncSignalsWithMainHandlers;
static uint32_t asyncSignalsWithMainHandlers;
#if defined(OMR_PORT_ASYNC_HANDLER)
static uint32_t shutDownASynchReporter;
#endif
static uint32_t attachedPortLibraries;
typedef struct OMRUnixAsyncHandlerRecord {
OMRPortLibrary *portLib;
omrsig_handler_fn handler;
void *handler_arg;
uint32_t flags;
struct OMRUnixAsyncHandlerRecord *next;
} OMRUnixAsyncHandlerRecord;
/* holds the options set by omrsig_set_options */
uint32_t signalOptionsGlobal;
static OMRUnixAsyncHandlerRecord *asyncHandlerList;
#if !defined(J9ZOS390)
#if defined(OSX)
#define SIGSEM_T sem_t *
#define SIGSEM_POST(_sem) sem_post(_sem)
#define SIGSEM_ERROR SEM_FAILED
#define SIGSEM_INIT(_sem, _name) ((_sem) = sem_open((_name), O_CREAT|O_EXCL, S_IRWXU, 0))
#define SIGSEM_UNLINK(_name) sem_unlink(_name)
#define SIGSEM_DESTROY(_sem) sem_close(_sem)
#define SIGSEM_WAIT(_sem) sem_wait(_sem)
#define SIGSEM_TRY_WAIT(_sem) sem_trywait(_sem)
#else /* defined(OSX) */
#define SIGSEM_T sem_t
#define SIGSEM_POST(_sem) sem_post(&(_sem))
#define SIGSEM_ERROR -1
#define SIGSEM_INIT(_sem, _name) sem_init(&(_sem), 0, 0)
#define SIGSEM_UNLINK(_name) do { /* do nothing */ } while (0)
#define SIGSEM_DESTROY(_sem) sem_destroy(&(_sem))
#define SIGSEM_WAIT(_sem) sem_wait(&(_sem))
#define SIGSEM_TRY_WAIT(_sem) sem_trywait(&(_sem))
#endif /* defined(OSX) */
static SIGSEM_T wakeUpASyncReporter;
#else /* !defined(J9ZOS390) */
/* The asyncSignalReporter synchronization has to be done differently on ZOS.
* z/OS does not have system semaphores, yet we can't rely on thread library
* being present for the mainASyncSignalHandler, so use pthread synchronization.
* Note: the use of pthread functions is allowed on z/OS
*/
static pthread_cond_t wakeUpASyncReporterCond;
static pthread_mutex_t wakeUpASyncReporterMutex;
#endif /* !defined(J9ZOS390) */
static omrthread_monitor_t asyncMonitor;
static omrthread_monitor_t registerHandlerMonitor;
static omrthread_monitor_t asyncReporterShutdownMonitor;
static uint32_t asyncThreadCount;
static uint32_t attachedPortLibraries;
struct OMRSignalHandlerRecord {
struct OMRSignalHandlerRecord *previous;
struct OMRPortLibrary *portLibrary;
omrsig_handler_fn handler;
void *handler_arg;
sigjmp_buf returnBuf;
#if defined(J9ZOS390)
struct __jumpinfo farJumpInfo;
#endif /* defined(J9ZOS390) */
uint32_t flags;
} OMRSignalHandlerRecord;
typedef struct OMRCurrentSignal {
int signal;
siginfo_t *sigInfo;
void *contextInfo;
#if defined(S390) && defined(LINUX)
uintptr_t breakingEventAddr;
#endif /* defined(S390) && defined(LINUX) */
uint32_t portLibSignalType;
} OMRCurrentSignal;
/* key to get the end of the synchronous handler records */
static omrthread_tls_key_t tlsKey;
/* key to get the current synchronous signal */
static omrthread_tls_key_t tlsKeyCurrentSignal;
static struct {
uint32_t portLibSignalNo;
int unixSignalNo;
} signalMap[] = {
{OMRPORT_SIG_FLAG_SIGSEGV, SIGSEGV},
{OMRPORT_SIG_FLAG_SIGBUS, SIGBUS},
{OMRPORT_SIG_FLAG_SIGILL, SIGILL},
{OMRPORT_SIG_FLAG_SIGFPE, SIGFPE},
{OMRPORT_SIG_FLAG_SIGTRAP, SIGTRAP},
{OMRPORT_SIG_FLAG_SIGQUIT, SIGQUIT},
{OMRPORT_SIG_FLAG_SIGABRT, SIGABRT},
{OMRPORT_SIG_FLAG_SIGTERM, SIGTERM},
{OMRPORT_SIG_FLAG_SIGXFSZ, SIGXFSZ},
{OMRPORT_SIG_FLAG_SIGINT, SIGINT},
{OMRPORT_SIG_FLAG_SIGHUP, SIGHUP},
{OMRPORT_SIG_FLAG_SIGCONT, SIGCONT},
{OMRPORT_SIG_FLAG_SIGWINCH, SIGWINCH},
{OMRPORT_SIG_FLAG_SIGPIPE, SIGPIPE},
{OMRPORT_SIG_FLAG_SIGALRM, SIGALRM},
{OMRPORT_SIG_FLAG_SIGCHLD, SIGCHLD},
{OMRPORT_SIG_FLAG_SIGTSTP, SIGTSTP},
{OMRPORT_SIG_FLAG_SIGUSR1, SIGUSR1},
{OMRPORT_SIG_FLAG_SIGUSR2, SIGUSR2},
{OMRPORT_SIG_FLAG_SIGURG, SIGURG},
{OMRPORT_SIG_FLAG_SIGXCPU, SIGXCPU},
{OMRPORT_SIG_FLAG_SIGVTALRM, SIGVTALRM},
{OMRPORT_SIG_FLAG_SIGPROF, SIGPROF},
{OMRPORT_SIG_FLAG_SIGIO, SIGIO},
{OMRPORT_SIG_FLAG_SIGSYS, SIGSYS},
{OMRPORT_SIG_FLAG_SIGTTIN, SIGTTIN},
{OMRPORT_SIG_FLAG_SIGTTOU, SIGTTOU}
#if defined(SIGINFO)
, {OMRPORT_SIG_FLAG_SIGINFO, SIGINFO}
#endif /* defined(SIGINFO) */
#if defined(SIGIOT)
, {OMRPORT_SIG_FLAG_SIGIOT, SIGIOT}
#endif /* defined(SIGIOT) */
#if defined(SIGPOLL)
, {OMRPORT_SIG_FLAG_SIGPOLL, SIGPOLL}
#endif /* defined(SIGPOLL) */
#if defined(SIGRECONFIG)
, {OMRPORT_SIG_FLAG_SIGRECONFIG, SIGRECONFIG}
#endif /* defined(SIGRECONFIG) */
#if defined(SIGABND)
, {OMRPORT_SIG_FLAG_SIGABEND, SIGABND}
#endif /* defined(SIGABND) */
};
static omrthread_t asynchSignalReporterThread = NULL;
static int32_t registerMainHandlers(OMRPortLibrary *portLibrary, uint32_t flags, uint32_t allowedSubsetOfFlags, void **oldOSHandler);
static void removeAsyncHandlers(OMRPortLibrary *portLibrary);
static uint32_t mapOSSignalToPortLib(uint32_t signalNo, siginfo_t *sigInfo);
#if defined(J9ZOS390)
static intptr_t addAsyncSignalsToSet(sigset_t *ss);
#endif /* defined(J9ZOS390) */
#if defined(OMR_PORT_ASYNC_HANDLER)
static void runHandlers(uint32_t asyncSignalFlag, int unixSignal);
static int J9THREAD_PROC asynchSignalReporter(void *userData);
#endif /* defined(OMR_PORT_ASYNC_HANDLER) */
static int32_t registerSignalHandlerWithOS(OMRPortLibrary *portLibrary, uint32_t portLibrarySignalNo, unix_sigaction handler, void **oldOSHandler);
static uint32_t destroySignalTools(OMRPortLibrary *portLibrary);
static int mapPortLibSignalToOSSignal(uint32_t portLibSignal);
static uint32_t countInfoInCategory(struct OMRPortLibrary *portLibrary, void *info, uint32_t category);
static void sig_full_shutdown(struct OMRPortLibrary *portLibrary);
static int32_t initializeSignalTools(OMRPortLibrary *portLibrary);
#if defined(S390) && defined(LINUX)
static void mainSynchSignalHandler(int signal, siginfo_t *sigInfo, void *contextInfo, uintptr_t breakingEventAddr);
static void mainASynchSignalHandler(int signal, siginfo_t *sigInfo, void *contextInfo, uintptr_t nullArg);
#else /* defined(S390) && defined(LINUX) */
static void mainSynchSignalHandler(int signal, siginfo_t *sigInfo, void *contextInfo);
static void mainASynchSignalHandler(int signal, siginfo_t *sigInfo, void *contextInfo);
#endif /* defined(S390) && defined(LINUX) */
static int32_t unblockSignal(int signal);
static void setBitMaskSignalsWithHandlers(uint32_t flags);
static void unsetBitMaskSignalsWithHandlers(uint32_t flags);
static void setBitMaskSignalsWithMainHandlers(uint32_t flags);
static void unsetBitMaskSignalsWithMainHandlers(uint32_t flags);
static BOOLEAN checkForAmbiguousSignalFlags(uint32_t flags, const char *functionName);
int32_t
omrsig_can_protect(struct OMRPortLibrary *portLibrary, uint32_t flags)
{
uint32_t supportedFlags = OMRPORT_SIG_FLAG_MAY_RETURN;
Trc_PRT_signal_omrsig_can_protect_entered(flags);
if (checkForAmbiguousSignalFlags(flags, "omrsig_can_protect")) {
return OMRPORT_SIG_ERROR;
}
#if !defined(J9ZOS390)
supportedFlags |= OMRPORT_SIG_FLAG_MAY_CONTINUE_EXECUTION;
#else /* !defined(J9ZOS390) */
if (TRUE == PPG_resumableTrapsSupported) {
Trc_PRT_sig_can_protect_OMRPORT_SIG_FLAG_MAY_CONTINUE_EXECUTION_supported();
supportedFlags |= OMRPORT_SIG_FLAG_MAY_CONTINUE_EXECUTION;
} else {
Trc_PRT_sig_can_protect_OMRPORT_SIG_FLAG_MAY_CONTINUE_EXECUTION_NOT_supported();
}
#endif /* !defined(J9ZOS390) */
if (OMR_ARE_NO_BITS_SET(signalOptionsGlobal, OMRPORT_SIG_OPTIONS_REDUCED_SIGNALS_SYNCHRONOUS)) {
supportedFlags |= OMRPORT_SIG_FLAG_SIGALLSYNC;
}
if (OMR_ARE_ALL_BITS_SET(supportedFlags, flags)) {
Trc_PRT_signal_omrsig_can_protect_exiting_is_able_to_protect(supportedFlags);
return 1;
}
Trc_PRT_signal_omrsig_can_protect_exiting_is_not_able_to_protect(supportedFlags);
return 0;
}
uint32_t
omrsig_info(struct OMRPortLibrary *portLibrary, void *info, uint32_t category, int32_t index, const char **name, void **value)
{
*name = "";
switch (category) {
case OMRPORT_SIG_SIGNAL:
return infoForSignal(portLibrary, info, index, name, value);
case OMRPORT_SIG_GPR:
return infoForGPR(portLibrary, info, index, name, value);
case OMRPORT_SIG_CONTROL:
return infoForControl(portLibrary, info, index, name, value);
case OMRPORT_SIG_MODULE:
return infoForModule(portLibrary, info, index, name, value);
case OMRPORT_SIG_FPR:
return infoForFPR(portLibrary, info, index, name, value);
#if defined(J9ZOS390)
case OMRPORT_SIG_VR:
if (portLibrary->portGlobals->vectorRegsSupportOn) {
return infoForVR(portLibrary, info, index, name, value);
}
#endif /* defined(J9ZOS390) */
case OMRPORT_SIG_OTHER:
default:
return OMRPORT_SIG_VALUE_UNDEFINED;
}
}
uint32_t
omrsig_info_count(struct OMRPortLibrary *portLibrary, void *info, uint32_t category)
{
return countInfoInCategory(portLibrary, info, category);
}
/**
* We register the main signal handlers here to deal with -Xrs
*/
int32_t
omrsig_protect(struct OMRPortLibrary *portLibrary, omrsig_protected_fn fn, void *fn_arg, omrsig_handler_fn handler, void *handler_arg, uint32_t flags, uintptr_t *result)
{
struct OMRSignalHandlerRecord thisRecord = {0};
omrthread_t thisThread = NULL;
uint32_t flagsSignalsOnly = flags & OMRPORT_SIG_FLAG_SIGALLSYNC;
uint32_t flagsWithoutMainHandlers = (flagsSignalsOnly & ~syncSignalsWithMainHandlers) & ~OMRPORT_SIG_FLAG_CONTROL_BITS_MASK;
Trc_PRT_signal_omrsig_protect_entered(fn, fn_arg, handler, handler_arg, flags);
if (checkForAmbiguousSignalFlags(flags, "omrsig_protect")) {
return OMRPORT_SIG_ERROR;
}
if (OMR_ARE_ANY_BITS_SET(signalOptionsGlobal, OMRPORT_SIG_OPTIONS_REDUCED_SIGNALS_SYNCHRONOUS)) {
/* -Xrs was set, we can't protect against any signals, do not install the main handler */
Trc_PRT_signal_omrsig_protect_cannot_protect_dueto_Xrs(fn, fn_arg, flags);
*result = fn(portLibrary, fn_arg);
Trc_PRT_signal_omrsig_protect_exiting_did_not_protect_due_to_Xrs(fn, fn_arg, handler, handler_arg, flags);
return 0;
}
if (0 != flagsWithoutMainHandlers) {
uint32_t rc = 0;
/* Acquire the registerHandlerMonitor and install the handler via registerMainHandlers. */
omrthread_monitor_enter(registerHandlerMonitor);
rc = registerMainHandlers(portLibrary, flags, OMRPORT_SIG_FLAG_SIGALLSYNC, NULL);
omrthread_monitor_exit(registerHandlerMonitor);
if (0 != rc) {
return OMRPORT_SIG_ERROR;
}
}
thisThread = omrthread_self();
thisRecord.previous = omrthread_tls_get(thisThread, tlsKey);
thisRecord.portLibrary = portLibrary;
thisRecord.handler = handler;
thisRecord.handler_arg = handler_arg;
thisRecord.flags = flags;
if (OMR_ARE_ANY_BITS_SET(flags, OMRPORT_SIG_FLAG_MAY_RETURN)) {
/* Record the current signal. We need to store this value back into tls if we jump back into this function
* because any signals that may have occurred within the scope of this layer of protection would have been handled
* by that point.
*
* The only scenario where this is of real concern, is if more than one signal was handled per call to omrsig_protect. In
* this case, the current signal in tls will be pointing at a stale stack frame and signal: CMVC 126838
*/
OMRCurrentSignal *currentSignal = omrthread_tls_get(thisThread, tlsKeyCurrentSignal);
/* setjmp/longjmp does not clear the mask setup by the OS when it delivers the signal. User sigsetjmp/siglongjmp(buf, 1) instead */
if (0 != sigsetjmp(thisRecord.returnBuf, 1)) {
/* the handler had long jumped back here -- reset the signal handler stack and currentSignal and return */
omrthread_tls_set(thisThread, tlsKey, thisRecord.previous);
omrthread_tls_set(thisThread, tlsKeyCurrentSignal, currentSignal);
*result = 0;
Trc_PRT_signal_omrsignal_sig_protect_Exit_long_jumped_back_to_omrsig_protect(fn, fn_arg, handler, handler_arg, flags);
return OMRPORT_SIG_EXCEPTION_OCCURRED;
}
}
if (0 != omrthread_tls_set(thisThread, tlsKey, &thisRecord)) {
Trc_PRT_signal_omrsignal_sig_protect_Exit_ERROR_accessing_tls(fn, fn_arg, handler, handler_arg, flags);
return OMRPORT_SIG_ERROR;
}
*result = fn(portLibrary, fn_arg);
/* if the first omrthread_tls_set succeeded, then this one will always succeed */
omrthread_tls_set(thisThread, tlsKey, thisRecord.previous);
Trc_PRT_signal_omrsignal_sig_protect_Exit_after_returning_from_fn(fn, fn_arg, handler, handler_arg, flags, *result);
return 0;
}
int32_t
omrsig_set_async_signal_handler(struct OMRPortLibrary *portLibrary, omrsig_handler_fn handler, void *handler_arg, uint32_t flags)
{
int32_t rc = 0;
OMRUnixAsyncHandlerRecord *cursor = NULL;
OMRUnixAsyncHandlerRecord **previousLink = NULL;
Trc_PRT_signal_omrsig_set_async_signal_handler_entered(handler, handler_arg, flags);
if (checkForAmbiguousSignalFlags(flags, "omrsig_set_async_signal_handler")) {
return OMRPORT_SIG_ERROR;
}
omrthread_monitor_enter(registerHandlerMonitor);
if (OMR_ARE_ANY_BITS_SET(signalOptionsGlobal, OMRPORT_SIG_OPTIONS_REDUCED_SIGNALS_ASYNCHRONOUS)) {
/* -Xrs was set, we can't protect against any signals, do not install any handlers except SIGXFSZ */
if (OMR_ARE_ALL_BITS_SET(flags, OMRPORT_SIG_FLAG_SIGXFSZ) && OMR_ARE_ANY_BITS_SET(signalOptionsGlobal, OMRPORT_SIG_OPTIONS_SIGXFSZ)) {
rc = registerMainHandlers(portLibrary, OMRPORT_SIG_FLAG_SIGXFSZ, OMRPORT_SIG_FLAG_SIGALLASYNC, NULL);
} else {
Trc_PRT_signal_omrsig_set_async_signal_handler_will_not_set_handler_due_to_Xrs(handler, handler_arg, flags);
rc = OMRPORT_SIG_ERROR;
}
} else {
rc = registerMainHandlers(portLibrary, flags, OMRPORT_SIG_FLAG_SIGALLASYNC, NULL);
}
omrthread_monitor_exit(registerHandlerMonitor);
if (0 != rc) {
Trc_PRT_signal_omrsig_set_async_signal_handler_exiting_did_nothing_possible_error(handler, handler_arg, flags);
return rc;
}
omrthread_monitor_enter(asyncMonitor);
/* wait until no signals are being reported */
while (asyncThreadCount > 0) {
omrthread_monitor_wait(asyncMonitor);
}
/* is this handler already registered? */
previousLink = &asyncHandlerList;
cursor = asyncHandlerList;
while (NULL != cursor) {
if ((cursor->portLib == portLibrary) && (cursor->handler == handler) && (cursor->handler_arg == handler_arg)) {
if (0 == flags) {
/* Remove the listener
* NOTE: mainHandlers get removed at omrsignal shutdown */
/* remove this handler record */
*previousLink = cursor->next;
portLibrary->mem_free_memory(portLibrary, cursor);
Trc_PRT_signal_omrsig_set_async_signal_handler_user_handler_removed(handler, handler_arg, flags);
} else {
/* update the listener with the new flags */
Trc_PRT_signal_omrsig_set_async_signal_handler_user_handler_added_1(handler, handler_arg, flags);
cursor->flags |= flags;
}
break;
}
previousLink = &cursor->next;
cursor = cursor->next;
}
if (NULL == cursor) {
/* cursor will only be NULL if we failed to find it in the list */
if (0 != flags) {
OMRUnixAsyncHandlerRecord *record = portLibrary->mem_allocate_memory(portLibrary, sizeof(*record), OMR_GET_CALLSITE(), OMRMEM_CATEGORY_PORT_LIBRARY);
if (NULL == record) {
rc = OMRPORT_SIG_ERROR;
} else {
record->portLib = portLibrary;
record->handler = handler;
record->handler_arg = handler_arg;
record->flags = flags;
record->next = NULL;
/* add the new record to the end of the list */
Trc_PRT_signal_omrsig_set_async_signal_handler_user_handler_added_2(handler, handler_arg, flags);
*previousLink = record;
}
}
}
omrthread_monitor_exit(asyncMonitor);
Trc_PRT_signal_omrsig_set_async_signal_handler_exiting(handler, handler_arg, flags);
return rc;
}
int32_t
omrsig_set_single_async_signal_handler(struct OMRPortLibrary *portLibrary, omrsig_handler_fn handler, void *handler_arg, uint32_t portlibSignalFlag, void **oldOSHandler)
{
int32_t rc = 0;
OMRUnixAsyncHandlerRecord *cursor = NULL;
OMRUnixAsyncHandlerRecord **previousLink = NULL;
BOOLEAN foundHandler = FALSE;
Trc_PRT_signal_omrsig_set_single_async_signal_handler_entered(handler, handler_arg, portlibSignalFlag);
if (0 != portlibSignalFlag) {
/* For non-zero portlibSignalFlag, check if only one signal bit is set. Otherwise, fail. */
if (!OMR_IS_ONLY_ONE_BIT_SET(portlibSignalFlag & ~OMRPORT_SIG_FLAG_CONTROL_BITS_MASK)) {
Trc_PRT_signal_omrsig_set_single_async_signal_handler_error_multiple_signal_flags_found(portlibSignalFlag);
return OMRPORT_SIG_ERROR;
}
if (checkForAmbiguousSignalFlags(portlibSignalFlag, "omrsig_set_single_async_signal_handler")) {
return OMRPORT_SIG_ERROR;
}
}
omrthread_monitor_enter(registerHandlerMonitor);
if (OMR_ARE_ANY_BITS_SET(signalOptionsGlobal, OMRPORT_SIG_OPTIONS_REDUCED_SIGNALS_ASYNCHRONOUS)) {
/* -Xrs was set, we can't protect against any signals, do not install any handlers except SIGXFSZ*/
if (OMR_ARE_ALL_BITS_SET(portlibSignalFlag, OMRPORT_SIG_FLAG_SIGXFSZ) && OMR_ARE_ANY_BITS_SET(signalOptionsGlobal, OMRPORT_SIG_OPTIONS_SIGXFSZ)) {
rc = registerMainHandlers(portLibrary, OMRPORT_SIG_FLAG_SIGXFSZ, OMRPORT_SIG_FLAG_SIGALLASYNC, oldOSHandler);
} else {
Trc_PRT_signal_omrsig_set_single_async_signal_handler_will_not_set_handler_due_to_Xrs(handler, handler_arg, portlibSignalFlag);
rc = OMRPORT_SIG_ERROR;
}
} else {
rc = registerMainHandlers(portLibrary, portlibSignalFlag, OMRPORT_SIG_FLAG_SIGALLASYNC, oldOSHandler);
}
omrthread_monitor_exit(registerHandlerMonitor);
if (0 != rc) {
Trc_PRT_signal_omrsig_set_single_async_signal_handler_exiting_did_nothing_possible_error(rc, handler, handler_arg, portlibSignalFlag);
return rc;
}
omrthread_monitor_enter(asyncMonitor);
/* wait until no signals are being reported */
while (asyncThreadCount > 0) {
omrthread_monitor_wait(asyncMonitor);
}
/* is this handler already registered? */
previousLink = &asyncHandlerList;
cursor = asyncHandlerList;
while (NULL != cursor) {
if (cursor->portLib == portLibrary) {
if ((cursor->handler == handler) && (cursor->handler_arg == handler_arg)) {
foundHandler = TRUE;
if (0 == portlibSignalFlag) {
/* Remove the listener. Remove this handler record.
* NOTE: mainHandlers get removed at omrsignal shutdown
*/
*previousLink = cursor->next;
portLibrary->mem_free_memory(portLibrary, cursor);
Trc_PRT_signal_omrsig_set_single_async_signal_handler_user_handler_removed(handler, handler_arg, portlibSignalFlag);
break;
} else {
/* Update the listener with the new portlibSignalFlag */
Trc_PRT_signal_omrsig_set_single_async_signal_handler_user_handler_added_1(handler, handler_arg, portlibSignalFlag);
cursor->flags |= portlibSignalFlag;
}
} else {
/* Unset the portlibSignalFlag for other handlers. One signal must be associated to only one handler. */
cursor->flags &= ~(portlibSignalFlag & ~OMRPORT_SIG_FLAG_CONTROL_BITS_MASK);
}
}
previousLink = &cursor->next;
cursor = cursor->next;
}
if (!foundHandler && (0 != portlibSignalFlag)) {
OMRUnixAsyncHandlerRecord *record = portLibrary->mem_allocate_memory(portLibrary, sizeof(*record), OMR_GET_CALLSITE(), OMRMEM_CATEGORY_PORT_LIBRARY);
if (NULL == record) {
rc = OMRPORT_SIG_ERROR;
} else {
record->portLib = portLibrary;
record->handler = handler;
record->handler_arg = handler_arg;
record->flags = portlibSignalFlag;
record->next = NULL;
/* add the new record to the end of the list */
Trc_PRT_signal_omrsig_set_single_async_signal_handler_user_handler_added_2(handler, handler_arg, portlibSignalFlag);
*previousLink = record;
}
}
omrthread_monitor_exit(asyncMonitor);
if (NULL != oldOSHandler) {
Trc_PRT_signal_omrsig_set_single_async_signal_handler_exiting(rc, handler, handler_arg, portlibSignalFlag, *oldOSHandler);
} else {
Trc_PRT_signal_omrsig_set_single_async_signal_handler_exiting(rc, handler, handler_arg, portlibSignalFlag, NULL);
}
return rc;
}
uint32_t
omrsig_map_os_signal_to_portlib_signal(struct OMRPortLibrary *portLibrary, uint32_t osSignalValue)
{
return mapOSSignalToPortLib(osSignalValue, NULL);
}
int32_t
omrsig_map_portlib_signal_to_os_signal(struct OMRPortLibrary *portLibrary, uint32_t portlibSignalFlag)
{
return (int32_t)mapPortLibSignalToOSSignal(portlibSignalFlag);
}
int32_t
omrsig_register_os_handler(struct OMRPortLibrary *portLibrary, uint32_t portlibSignalFlag, void *newOSHandler, void **oldOSHandler)
{
int32_t rc = 0;
Trc_PRT_signal_omrsig_register_os_handler_entered(portlibSignalFlag, newOSHandler);
if ((0 == portlibSignalFlag) || !OMR_IS_ONLY_ONE_BIT_SET(portlibSignalFlag & ~OMRPORT_SIG_FLAG_CONTROL_BITS_MASK)) {
/* If portlibSignalFlag is 0 or if portlibSignalFlag has multiple signal bits set, then fail. */
Trc_PRT_signal_omrsig_register_os_handler_invalid_portlibSignalFlag(portlibSignalFlag);
rc = OMRPORT_SIG_ERROR;
} else if (checkForAmbiguousSignalFlags(portlibSignalFlag, "omrsig_register_os_handler")) {
return OMRPORT_SIG_ERROR;
} else {
omrthread_monitor_enter(registerHandlerMonitor);
rc = registerSignalHandlerWithOS(portLibrary, portlibSignalFlag, (unix_sigaction)newOSHandler, oldOSHandler);
omrthread_monitor_exit(registerHandlerMonitor);
}
if (NULL != oldOSHandler) {
Trc_PRT_signal_omrsig_register_os_handler_exiting(rc, portlibSignalFlag, newOSHandler, *oldOSHandler);
} else {
Trc_PRT_signal_omrsig_register_os_handler_exiting(rc, portlibSignalFlag, newOSHandler, NULL);
}
return rc;
}
BOOLEAN
omrsig_is_main_signal_handler(struct OMRPortLibrary *portLibrary, void *osHandler)
{
BOOLEAN rc = FALSE;
Trc_PRT_signal_omrsig_is_main_signal_handler_entered(osHandler);
if ((osHandler == (void *)mainSynchSignalHandler)
|| (osHandler == (void *)mainASynchSignalHandler)
) {
rc = TRUE;
}
Trc_PRT_signal_omrsig_is_main_signal_handler_exiting(rc);
return rc;
}
int32_t
omrsig_is_signal_ignored(struct OMRPortLibrary *portLibrary, uint32_t portlibSignalFlag, BOOLEAN *isSignalIgnored)
{
int32_t rc = 0;
int osSignalNo = OMRPORT_SIG_ERROR;
void *oldHandler = NULL;
struct sigaction oldSignalAction;
Trc_PRT_signal_omrsig_is_signal_ignored_entered(portlibSignalFlag);
*isSignalIgnored = FALSE;
if (0 != portlibSignalFlag) {
/* For non-zero portlibSignalFlag, check if only one signal bit is set. Otherwise, fail. */
if (!OMR_IS_ONLY_ONE_BIT_SET(portlibSignalFlag & ~OMRPORT_SIG_FLAG_CONTROL_BITS_MASK)) {
rc = OMRPORT_SIG_ERROR;
goto exit;
}
if (checkForAmbiguousSignalFlags(portlibSignalFlag, "omrsig_is_signal_ignored")) {
return OMRPORT_SIG_ERROR;
}
}
osSignalNo = mapPortLibSignalToOSSignal(portlibSignalFlag);
if (OMRPORT_SIG_ERROR == osSignalNo) {
rc = OMRPORT_SIG_ERROR;
goto exit;
}
memset(&oldSignalAction, 0, sizeof(struct sigaction));
OMRSIG_SIGACTION(osSignalNo, NULL, &oldSignalAction);
oldHandler = (void *)oldSignalAction.sa_sigaction;
if (NULL == oldHandler) {
oldHandler = (void *)oldSignalAction.sa_handler;
}
if (oldHandler == (void *)SIG_IGN) {
*isSignalIgnored = TRUE;
}
exit:
Trc_PRT_signal_omrsig_is_signal_ignored_exiting(rc, *isSignalIgnored);
return rc;
}
/*
* The full shutdown routine "sig_full_shutdown" overwrites this once we've completed startup
*/
void
omrsig_shutdown(struct OMRPortLibrary *portLibrary)
{
Trc_PRT_signal_omrsig_shutdown_empty_routine(portLibrary);
return;
}
/**
* Start up the signal handling component of the port library
*
* Note: none of the main handlers are registered with the OS until the first call to either of omrsig_protect or omrsig_set_async_signal_handler
*/
int32_t
omrsig_startup(struct OMRPortLibrary *portLibrary)
{
int32_t result = 0;
omrthread_monitor_t globalMonitor = NULL;
uint32_t index = 1;
Trc_PRT_signal_omrsig_startup_entered(portLibrary);
globalMonitor = omrthread_global_monitor();
omrthread_monitor_enter(globalMonitor);
if (attachedPortLibraries++ == 0) {
/* initialize the old actions */
for (index = 1; index < ARRAY_SIZE_SIGNALS; index++) {
oldActions[index].restore = 0;
}
result = initializeSignalTools(portLibrary);
}
omrthread_monitor_exit(globalMonitor);
if (result == 0) {
/* we have successfully started up the signal portion, install the full shutdown routine */
portLibrary->sig_shutdown = sig_full_shutdown;
}
Trc_PRT_signal_omrsig_startup_exiting(portLibrary, result);
return result;
}
static uint32_t
countInfoInCategory(struct OMRPortLibrary *portLibrary, void *info, uint32_t category)
{
void *value = NULL;
const char *name = NULL;
uint32_t count = 0;
while (portLibrary->sig_info(portLibrary, info, category, count, &name, &value) != OMRPORT_SIG_VALUE_UNDEFINED) {
count++;
}
return count;
}
#if defined(OMR_PORT_ASYNC_HANDLER)
/**
* Given a port library signal flag and Unix signal value, execute the associated handlers
* stored within asyncHandlerList (list of OMRUnixAsyncHandlerRecord).
*
* @param asyncSignalFlag port library signal flag
* @param unixSignal Unix signal value
*
* @return void
*/
static void
runHandlers(uint32_t asyncSignalFlag, int unixSignal)
{
OMRUnixAsyncHandlerRecord *cursor = asyncHandlerList;
/* report the signal recorded in signalType to all registered listeners (for this signal).
* incrementing the asyncThreadCount will prevent the list from being modified while we use it.
*/
omrthread_monitor_enter(asyncMonitor);
asyncThreadCount++;
omrthread_monitor_exit(asyncMonitor);
while (NULL != cursor) {
if (OMR_ARE_ALL_BITS_SET(cursor->flags, asyncSignalFlag)) {
Trc_PRT_signal_omrsig_asynchSignalReporter_calling_handler(cursor->portLib, asyncSignalFlag, cursor->handler_arg);
cursor->handler(cursor->portLib, asyncSignalFlag, NULL, cursor->handler_arg);
}
cursor = cursor->next;
}
omrthread_monitor_enter(asyncMonitor);
if (--asyncThreadCount == 0) {
omrthread_monitor_notify_all(asyncMonitor);
}
omrthread_monitor_exit(asyncMonitor);
#if defined(OMRPORT_OMRSIG_SUPPORT)
if (OMR_ARE_NO_BITS_SET(signalOptionsGlobal, OMRPORT_SIG_OPTIONS_OMRSIG_NO_CHAIN)) {
/* mapPortLibSignalToOSSignal returns OMRPORT_SIG_ERROR (-1) on unknown mapping */
if (OMRPORT_SIG_ERROR != unixSignal) {
omrsig_handler(unixSignal, NULL, NULL);
}
}
#endif /* defined(OMRPORT_OMRSIG_SUPPORT) */
}
/**
* Reports the asynchronous signal to all listeners.
*/
static int J9THREAD_PROC
asynchSignalReporter(void *userData)
{
#if defined(J9ZOS390)
/*
* CMVC 192198
* Prevent async signals that are handled by mainASynchSignalHandler()
* from being caught by this thread. We can't allow mainASynchSignalHandler()
* to recursively lock wakeUpASyncReporterMutex because it could cause this
* thread to miss signals on wakeUpASyncReporterCond.
*
* It's ok if this thread caught a signal just before this, because it has
* not locked wakeUpASyncReporterMutex yet.
*
* This limitation is unique to the z/OS implementation of async signal handling.
*/
{
sigset_t asyncSigs;
intptr_t rc = 0;
int osRc = 0;
osRc = sigemptyset(&asyncSigs);
Assert_PRT_true(0 == osRc);
rc = addAsyncSignalsToSet(&asyncSigs);
Assert_PRT_true(0 == rc);
osRc = sigprocmask(SIG_BLOCK, &asyncSigs, NULL);
Assert_PRT_true(0 == osRc);
}
#endif /* defined(J9ZOS390) */
omrthread_set_name(omrthread_self(), "Signal Reporter");
while (0 == shutDownASynchReporter) {
int unixSignal = 1;
uint32_t asyncSignalFlag = 0;
#if !defined(J9ZOS390)
/* CMVC 119663 sem_wait can return -1/EINTR on signal in NPTL */
while (0 != SIGSEM_WAIT(wakeUpASyncReporter));
#endif /* !defined(J9ZOS390) */
/* determine which signal we've been woken up for */
for (unixSignal = 1; unixSignal < ARRAY_SIZE_SIGNALS; unixSignal++) {
uintptr_t signalCount = signalCounts[unixSignal];
if (signalCount > 0) {
asyncSignalFlag = mapOSSignalToPortLib(unixSignal, NULL);
runHandlers(asyncSignalFlag, unixSignal);
subtractAtomic(&signalCounts[unixSignal], 1);
#if defined(J9ZOS390)
/* Before waiting on the condvar, we need to make sure all
* signals are handled. This will allow us to handle all signals
* even if some wake signals for the condvar are missed. Reset
* unixSignal to 0. for loop will start again with unixSignal = 1.
*/
unixSignal = 0;
#else /* defined(J9ZOS390) */
/* sem_wait will fall-through for each sem_post. We can handle
* one signal at a time. Ultimately, all signals will be handled
* So, break out of the for loop.
*/
break;
#endif /* defined(J9ZOS390) */
}
}
#if defined(J9ZOS390)
/* Only wait if no signal is pending and shutdown isn't requested. */
if (0 == shutDownASynchReporter) {
/* I won't attempt to generate diagnostics if the following pthread
* functions return errors because it may interfere with diagnostics
* we are attempting to generate for earlier events.
*/
Trc_PRT_signal_omrsig_asynchSignalReporterThread_going_to_sleep();
pthread_mutex_lock(&wakeUpASyncReporterMutex);
pthread_cond_wait(&wakeUpASyncReporterCond, &wakeUpASyncReporterMutex);
pthread_mutex_unlock(&wakeUpASyncReporterMutex);
}
#endif /* defined(J9ZOS390) */
Trc_PRT_signal_omrsig_asynchSignalReporter_woken_up();
}
omrthread_monitor_enter(asyncReporterShutdownMonitor);
shutDownASynchReporter = 0;
omrthread_monitor_notify(asyncReporterShutdownMonitor);
omrthread_exit(asyncReporterShutdownMonitor);
/* unreachable */
return 0;
}
#endif /* defined(OMR_PORT_ASYNC_HANDLER) */
/**
* This signal handler is specific to synchronous signals.
* It will call all of the user's handlers that were registered with the vm using omrsig_protect,
* upon receiving a signal they listen for.
*
*/
#if defined(S390) && defined(LINUX)
static void
mainSynchSignalHandler(int signal, siginfo_t *sigInfo, void *contextInfo, uintptr_t breakingEventAddr)
#else /* defined(S390) && defined(LINUX) */
static void
mainSynchSignalHandler(int signal, siginfo_t *sigInfo, void *contextInfo)
#endif /* defined(S390) && defined(LINUX) */
{
#if defined(LINUXPPC)
/*
* PR 56956: ensure the right register context is used if a signal occurs in a transaction.
* If there is a signal during a transaction, two contexts are provided: one for the start of the transaction
* and one for the context within the transaction.
*
* On Power 8 Linux, if a signal occurs during a transaction,
* the transaction aborts and the corresponding signal handler is invoked with the context from the start of the transaction.
* The mainSynchSignalHandler determines if the signal occurred within a transaction,
* and if so, returns such that the transaction is executed in the failed state,
* causing the non-transactional failure path to be taken (referred to as the "abort handler" in
* https://www.kernel.org/doc/Documentation/powerpc/transactional_memory.txt).
* Note: this means signals that occur during the transaction, but not in the failure path, are lost.
* Please see Jazz design 63039: Handle signals in PowerPC transactional memory operations for further discussion.
*/
/*
* This contains two contexts: the context at the start of the transaction, plus a link to the
* context within the transaction. We use the former, other than to determine the transaction state.
*/
ucontext_t *platformContext = contextInfo;
/*
* Check the Transaction State (TS) bits
* for either 01 (Suspended) or 10 (Transactional)
*/
#if defined(LINUXPPC64)
#define MSR_TS_MASK 0x600000000ULL
if (OMR_ARE_ANY_BITS_SET(platformContext->uc_mcontext.regs->msr, MSR_TS_MASK))
/* the transactional context is in the high order bits */
#else /* defined(LINUXPPC64) */
#define MSR_TS_MASK 0x6U
/*
* in 32-bit CPUs, the second context containing the transactional
* state is in a separate ucontext datastructure pointed to by uc_link.
*/
if ((NULL != platformContext->uc_link) && OMR_ARE_ANY_BITS_SET(platformContext->uc_link->uc_mcontext.regs->msr, MSR_TS_MASK))
#endif /* defined(LINUXPPC64) */
{
/*
* resume the transaction in the failed state, so it executes the failure path.
*/