os_result
os_signalHandlerFinishExitRequest(
os_callbackArg arg)
{
os_result r = os_resultSuccess;
int sig = (int)(os_address)arg.sig;
os_sigaction * xo;
/* This is a request from the application to round up an (asynchronous)
* exit-request. */
if (sig < 1 || sig >= OS_NSIG){
OS_REPORT(OS_WARNING,
"os_signalHandlerFinishExitRequest", 0,
"Callback-arg contains invalid signal, value out of range 1-%d: arg = %d",
OS_NSIG, sig);
r = os_resultInvalid;
} else if (sigismember(&quitsMask, sig) == 0){
#if OS_NSIG >= 100
#error "Worst-case allocation assumes max. signal of 99, which apparently is not correct"
#endif
/* We know which signal-number exist, all take at most 2 digits + ", ",
* so allocate worst-case 4 * quits_len */
char *expected = os_malloc(quits_len * 4 + 1);
if(expected){
unsigned i;
int pos;
assert(quits_len > 0);
pos = sprintf(expected, "%d", quits[0]);
for(i = 1; i < quits_len; i++){
pos += sprintf(expected + pos, ", %d", quits[i]);
}
}
OS_REPORT(OS_WARNING,
"os_signalHandlerFinishExitRequest", 0,
"Unexpected Signal, value out of range: signal = %d. Expected one of %s.",
sig, expected ? expected : "the asynchronous exit request signals");
os_free(expected);
r = os_resultInvalid;
}
if(r == os_resultSuccess){
/* We need to restore the original signal-handler and than re-raise the
* original signal. */
xo = &old_signalHandler[sig];
if(os_sigactionSet(sig, xo, NULL) != 0){
OS_REPORT(OS_WARNING,
"os_signalHandlerFinishExitRequest", 0,
"Resetting original signal handler for signal %d failed, sigaction did not return 0.",sig);
abort(); /* We were unable to reset the original handler, which is pretty serious. */
} else {
os_sigset current_sigset, old_sigset;
/* Determine the current mask, and make sure that the signal to be
* raised is not blocked (this code is typically executed in the
* signalHandlerThread (if callback is implemented synchronously),
* which blocks all signals). */
os_sigThreadSetMask(NULL, ¤t_sigset);
os_sigsetDel(¤t_sigset, sig);
raise(sig);
/* Set mask temporarily, this should raise the pending signal set above. */
os_sigThreadSetMask(¤t_sigset, &old_sigset);
/* Reset the mask to the original state. If this is the signal-
* HandlerThread this is essential (if sig is handled), otherwise just
* the proper thing to do. */
os_sigThreadSetMask(&old_sigset, NULL);
}
}
return r;
}
static os_result
os_signalHandlerInit(
os_signalHandler _this)
{
os_result result = os_resultSuccess;
os_sigset block_all_sigset, old_sigset;
unsigned i;
int r;
os_threadAttr thrAttr;
assert(_this);
_this->handleExceptions = OS_FALSE;
if(os__signalHandlerCallbackInit(&_this->callbackInfo) != os_resultSuccess) {
goto err_callbackInfoInit;
}
if(!isSignallingSafe(1)){
return os_resultSuccess;
}
/* Initialise the exceptionsMask */
sigemptyset(&exceptionsMask);
for(i = 0; i < lengthof(exceptions); i++){
sigaddset(&exceptionsMask, exceptions[i]);
}
/* Initialise the quitsMask */
sigemptyset(&quitsMask);
for(i = 0; i < quits_len; i++){
sigaddset(&quitsMask, quits[i]);
}
/* create signal handling pipes */
r = pipe(_this->pipeIn);
if (r < 0) {
OS_REPORT(OS_ERROR, "os_signalHandlerInit", 0, "pipe(_this->pipeIn) failed, result = %d", r);
goto err_pipeIn;
}
r = fcntl(_this->pipeIn[0], F_SETFD, 1);
if (r < 0) {
OS_REPORT(OS_WARNING, "os_signalHandlerInit", 0, "fcntl(_this->pipeIn[0]) failed, result = %d", r);
goto err_pipeInFcntl;
}
r = fcntl(_this->pipeIn[1], F_SETFD, 1);
if (r < 0) {
OS_REPORT(OS_WARNING, "os_signalHandlerInit", 0, "fcntl(_this->pipeIn[1]) failed, result = %d", r);
goto err_pipeInFcntl;
}
r = pipe(_this->pipeOut);
if (r < 0) {
OS_REPORT(OS_ERROR, "os_signalHandlerInit", 1, "pipe(_this->pipeOut) failed, result = %d", r);
goto err_pipeOut;
}
r = fcntl(_this->pipeOut[0], F_SETFD, 1);
if (r < 0) {
OS_REPORT(OS_WARNING, "os_signalHandlerInit", 0, "fcntl(_this->pipeOut[0]) failed, result = %d", r);
goto err_pipeOutFcntl;
}
r = fcntl(_this->pipeOut[1], F_SETFD, 1);
if (r < 0) {
OS_REPORT(OS_WARNING, "os_signalHandlerInit", 0, "fcntl(_this->pipeOut[1]) failed, result = %d", r);
goto err_pipeOutFcntl;
}
/* Block all signals in order to start the signalHandlerThread with all
* signals blocked. */
result = os_sigsetFill(&block_all_sigset);
if (result != os_resultSuccess) {
OS_REPORT(OS_ERROR, "os_signalHandlerInit", 0,
"os_sigsetFill(&block_all_sigset) failed: %s", os_resultImage(result));
goto err_sigsetMask;
}
/* Remove signals that cannot be blocked. */
for (i = 0; i < lengthof(excludes); i++) {
const int sig = excludes[i];
if (os_sigsetDel(&block_all_sigset, sig) != 0) {
OS_REPORT(OS_ERROR, "os_signalHandlerInit", 0, "os_sigsetDel(0x%"PA_PRIxADDR", %d) failed, result = %d",
(os_address)&_this->action, sig, r);
goto err_sigsetMask;
}
}
result = os_sigThreadSetMask(&block_all_sigset, &old_sigset);
if (result != os_resultSuccess) {
OS_REPORT(OS_ERROR, "os_signalHandlerInit", 0, "os_sigThreadSetMask(0x%"PA_PRIxADDR", 0x%"PA_PRIxADDR") failed: %s",
(os_address)&block_all_sigset, (os_address)&old_sigset, os_resultImage(result));
goto err_sigsetMask;
}
/* Setup signal handler thread. */
os_threadAttrInit(&thrAttr);
thrAttr.stackSize = 4*1024*1024; /* 4 MB */
result = os_threadCreate(&_this->threadId,
"signalHandler",
&thrAttr,
signalHandlerThread,
(void*)_this);
if (result != os_resultSuccess) {
OS_REPORT(OS_ERROR, "os_signalHandlerInit", 0,
"os_threadCreate(0x%"PA_PRIxADDR", 0x%"PA_PRIxADDR",0x%"PA_PRIxADDR",0) failed: %s",
(os_address)&_this->threadId,
(os_address)&thrAttr,
(os_address)signalHandlerThread,
os_resultImage(result));
goto err_threadCreate;
}
/* Reset signal mask to original value. */
result = os_sigThreadSetMask(&old_sigset, NULL);
if (result != os_resultSuccess) {
OS_REPORT(OS_ERROR, "os_signalHandlerInit", 0,
"os_sigThreadSetMask(0x%"PA_PRIxADDR", NULL) failed: %s",
(os_address)&old_sigset, os_resultImage(result));
goto err_sigResetMask;
}
/* install signal handlers */
_this->action = os_sigactionNew(signalHandler, &block_all_sigset, SA_SIGINFO);
if (os_signalHandlerEnableExitSignals() != os_resultSuccess) {
goto err_enableExitHandling;
}
return os_resultSuccess;
/* Error handling */
err_enableExitHandling:
err_sigResetMask:
os__signalHandlerThreadStop(_this);
err_threadCreate:
(void) os_sigThreadSetMask(&old_sigset, NULL);
err_sigsetMask:
/* No undo needed for fcntl's/sigsetFill */
err_pipeOutFcntl:
(void) close(_this->pipeOut[0]);
(void) close(_this->pipeOut[1]);
err_pipeOut:
/* No undo needed for fcntl's */
err_pipeInFcntl:
(void) close(_this->pipeIn[0]);
(void) close(_this->pipeIn[1]);
err_pipeIn:
os__signalHandlerCallbackDeinit(&_this->callbackInfo);
err_callbackInfoInit:
return os_resultFail;
}
static os_result
os_signalHandlerInit(
os_signalHandler _this)
{
os_result result = os_resultSuccess;
os_sigaction action;
os_sigset block_all_sigset, old_sigset;
int i, r;
if (_this == NULL) {
result = os_resultFail;
}
_this->exitRequestCallback = (os_signalHandlerExitRequestCallback)0;
_this->exceptionCallback = (os_signalHandlerExceptionCallback)0;
if(isSignallingSafe(1)) {
/* Initialise the exceptionsMask */
sigemptyset(&exceptionsMask);
for(i = 0; i < lengthof(exceptions); i++) {
sigaddset(&exceptionsMask, exceptions[i]);
}
/* Initialise the quitsMask */
sigemptyset(&quitsMask);
for(i = 0; i < lengthof(quits); i++) {
sigaddset(&quitsMask, quits[i]);
}
/* create signal handling pipes */
if (result == os_resultSuccess) {
r = pipe(_this->pipeIn);
if (r<0) {
OS_REPORT_1(OS_ERROR,
"os_signalHandlerInit", 0,
"pipe(_this->pipeIn) failed, result = %d",
r);
result = os_resultFail;
} else {
r = fcntl(_this->pipeIn[0], F_SETFD, 1);
if (r<0) {
OS_REPORT_1(OS_WARNING,
"os_signalHandlerInit", 0,
"fcntl(_this->pipeIn[0]) failed, result = %d", r);
assert(OS_FALSE);
}
r = fcntl(_this->pipeIn[1], F_SETFD, 1);
if (r<0) {
OS_REPORT_1(OS_WARNING,
"os_signalHandlerInit", 0,
"fcntl(_this->pipeIn[1]) failed, result = %d", r);
assert(OS_FALSE);
}
}
}
if (result == os_resultSuccess) {
r = pipe(_this->pipeOut);
if (r<0) {
OS_REPORT_1(OS_ERROR,
"os_signalHandlerInit", 1,
"pipe(_this->pipeOut) failed, result = %d",
r);
result = os_resultFail;
} else {
r = fcntl(_this->pipeOut[0], F_SETFD, 1);
if (r<0) {
OS_REPORT_1(OS_WARNING,
"os_signalHandlerInit", 0,
"fcntl(_this->pipeOut[0]) failed, result = %d",
r);
assert(OS_FALSE);
}
r = fcntl(_this->pipeOut[1], F_SETFD, 1);
if (r<0) {
OS_REPORT_1(OS_WARNING,
"os_signalHandlerInit", 0,
"fcntl(_this->pipeOut[1]) failed, result = %d",
r);
assert(OS_FALSE);
}
}
}
/* Block all signals */
if (result == os_resultSuccess) {
result = os_sigsetFill(&block_all_sigset);
if (result != os_resultSuccess) {
OS_REPORT_1(OS_ERROR,
"os_signalHandlerInit", 0,
"os_sigsetFill(&block_all_sigset) failed, result = %d",
r);
assert(OS_FALSE);
} else {
result = os_sigThreadSetMask(&block_all_sigset, &old_sigset);
if (result != os_resultSuccess) {
OS_REPORT_3(OS_ERROR,
"os_signalHandlerInit", 0,
"os_sigThreadSetMask(0x%x, 0x%x) failed, result = %d",
&block_all_sigset, &old_sigset, r);
assert(OS_FALSE);
}
}
}
/* Setup signal handler thread. */
if (result == os_resultSuccess) {
os_threadAttr thrAttr;
result = os_threadAttrInit(&thrAttr);
if (result != os_resultSuccess) {
OS_REPORT_2(OS_ERROR,
"os_signalHandlerInit", 0,
"pthread_attr_init(0x%x) failed, result = %d",
&thrAttr, r);
assert(OS_FALSE);
} else {
thrAttr.stackSize = 4*1024*1024; /* 4 MB */
result = os_threadCreate(&_this->threadId,
"signalHandler",
&thrAttr,
signalHandlerThread,
(void*)_this);
if (result != os_resultSuccess) {
OS_REPORT_4(OS_ERROR,
"os_signalHandlerInit", 0,
"os_threadCreate(0x%x, 0x%x,0x%x,0) failed, result = %d",
&_this->threadId,
&thrAttr,
signalHandlerThread,
result);
assert(OS_FALSE);
}
}
}
/* Reset signal mask to original value. */
if (result == os_resultSuccess) {
result = os_sigThreadSetMask(&old_sigset, NULL);
if (result != os_resultSuccess) {
OS_REPORT_2(OS_ERROR,
"os_signalHandlerInit", 0,
"os_sigThreadSetMask(0x%x, NULL) failed, result = %d",
&old_sigset, r);
result = os_resultFail;
assert(OS_FALSE);
}
}
/* install signal handlers */
if (result == os_resultSuccess) {
os_sigset mask;
/* block all signals during handling of a signal */
result = os_sigsetFill(&mask);
if (result != os_resultSuccess) {
OS_REPORT_2(OS_ERROR,
"os_signalHandlerInit", 0,
"os_sigsetFill(0x%x) failed, result = %d",
&action.sa_mask, result);
} else {
action = os_sigactionNew(signalHandler, &mask, SA_SIGINFO);
}
if (result == os_resultSuccess) {
for (i=0; i<lengthof(exceptions); i++) {
const int sig = exceptions[i];
r = os_sigsetDel(&action.sa_mask, sig);
if (r<0) {
OS_REPORT_3(OS_ERROR,
"os_signalHandlerInit", 0,
"os_sigsetDel(0x%x, %d) failed, result = %d",
&action, sig, r);
result = os_resultFail;
assert(OS_FALSE);
}
}
}
if (result == os_resultSuccess) {
for (i=0; i<lengthof(exceptions); i++) {
const int sig = exceptions[i];
/* For exceptions we always set our own signal handler, since
* applications that cause an exception are not in a position
* to ignore it. However, we will chain the old handler to our
* own.
*/
r = os_sigactionSet(sig, &action, &old_signalHandler[sig]);
if (r < 0) {
OS_REPORT_4(OS_ERROR,
"os_signalHandlerInit", 0,
"os_sigactionSet(%d, 0x%x, 0x%x) failed, result = %d",
sig, &action, &old_signalHandler[sig], r);
result = os_resultFail;
assert(OS_FALSE);
}
}
}
if (result == os_resultSuccess) {
for (i=0; i<lengthof(quits); i++) {
const int sig = quits[i];
/* By passing NULL we only retrieve the currently set handler. If
* the signal should be ignored, we don't do anything. Otherwise we
* chain the old handler to our own.
* man-page of sigaction only states behaviour when new
* action is non-NULL, but all known implementations act as
* expected. That is: return the currently set signal-hand-
* ler (and not the previous, as the man-pages state).
* NOTE: Not MT-safe */
r = os_sigactionSet(sig, NULL, &old_signalHandler[sig]);
if (r == 0) {
if(old_signalHandler[sig].sa_handler != SIG_IGN) {
/* We don't know if the oldHandler has been modified in the mean
* time, since there is no way to make the signal handler reentrant.
* It doesn't make sense to look for modifications now, since a
* new modification could be on its way while we are processing
* the current modification.
* For that reason we will ignore any intermediate modifications
* and continue setting our own handler. Processes should therefore
* refrain from modifying the signal handler in multiple threads.
*/
r = os_sigactionSet(sig, &action, NULL);
if (r != 0) {
OS_REPORT_4(OS_ERROR,
"os_signalHandlerInit", 0,
"os_sigactionSet(%d, 0x%x, 0x%x) failed, result = %d",
sig, &action, &old_signalHandler[sig], r);
result = os_resultFail;
assert(OS_FALSE);
}
} else {
OS_REPORT_1(OS_INFO,
"os_signalHandlerThread", 0,
"Not installing a signal handler for the already ignored signal %d.",
sig);
}
} else {
OS_REPORT_1(OS_ERROR, "os_signalHandlerInit", 0, "Could not retrieve currently set signal-handler for signal %d", sig);
result = os_resultFail;
assert(OS_FALSE);
}
}
}
}
} else {
result = os_resultSuccess;
}
return result;
}