fsfw/osal/linux/BinarySemaphore.cpp
2020-09-18 13:15:14 +02:00

150 lines
3.8 KiB
C++

#include "../../osal/linux/BinarySemaphore.h"
#include "../../serviceinterface/ServiceInterfaceStream.h"
extern "C" {
#include <errno.h>
#include <string.h>
}
BinarySemaphore::BinarySemaphore() {
// Using unnamed semaphores for now
initSemaphore();
}
BinarySemaphore::~BinarySemaphore() {
sem_destroy(&handle);
}
BinarySemaphore::BinarySemaphore(BinarySemaphore&& s) {
initSemaphore();
}
BinarySemaphore& BinarySemaphore::operator =(
BinarySemaphore&& s) {
initSemaphore();
return * this;
}
ReturnValue_t BinarySemaphore::acquire(TimeoutType timeoutType,
uint32_t timeoutMs) {
int result = 0;
if(timeoutType == TimeoutType::POLLING) {
result = sem_trywait(&handle);
}
else if(timeoutType == TimeoutType::BLOCKING) {
result = sem_wait(&handle);
}
else if(timeoutType == TimeoutType::WAITING){
timespec timeOut;
clock_gettime(CLOCK_REALTIME, &timeOut);
uint64_t nseconds = timeOut.tv_sec * 1000000000 + timeOut.tv_nsec;
nseconds += timeoutMs * 1000000;
timeOut.tv_sec = nseconds / 1000000000;
timeOut.tv_nsec = nseconds - timeOut.tv_sec * 1000000000;
result = sem_timedwait(&handle, &timeOut);
if(result != 0 and errno == EINVAL) {
sif::debug << "BinarySemaphore::acquire: Invalid time value possible"
<< std::endl;
}
}
if(result == 0) {
return HasReturnvaluesIF::RETURN_OK;
}
switch(errno) {
case(EAGAIN):
// Operation could not be performed without blocking (for sem_trywait)
case(ETIMEDOUT):
// Semaphore is 0
return SemaphoreIF::SEMAPHORE_TIMEOUT;
case(EINVAL):
// Semaphore invalid
return SemaphoreIF::SEMAPHORE_INVALID;
case(EINTR):
// Call was interrupted by signal handler
sif::debug << "BinarySemaphore::acquire: Signal handler interrupted."
"Code " << strerror(errno) << std::endl;
/* No break */
default:
return HasReturnvaluesIF::RETURN_FAILED;
}
}
ReturnValue_t BinarySemaphore::release() {
return BinarySemaphore::release(&this->handle);
}
ReturnValue_t BinarySemaphore::release(sem_t *handle) {
ReturnValue_t countResult = checkCount(handle, 1);
if(countResult != HasReturnvaluesIF::RETURN_OK) {
return countResult;
}
int result = sem_post(handle);
if(result == 0) {
return HasReturnvaluesIF::RETURN_OK;
}
switch(errno) {
case(EINVAL):
// Semaphore invalid
return SemaphoreIF::SEMAPHORE_INVALID;
case(EOVERFLOW):
// SEM_MAX_VALUE overflow. This should never happen
default:
return HasReturnvaluesIF::RETURN_FAILED;
}
}
uint8_t BinarySemaphore::getSemaphoreCounter() const {
// And another ugly cast :-D
return getSemaphoreCounter(const_cast<sem_t*>(&this->handle));
}
uint8_t BinarySemaphore::getSemaphoreCounter(sem_t *handle) {
int value = 0;
int result = sem_getvalue(handle, &value);
if (result == 0) {
return value;
}
else if(result != 0 and errno == EINVAL) {
// Could be called from interrupt, use lightweight printf
printf("BinarySemaphore::getSemaphoreCounter: Invalid semaphore\n");
return 0;
}
else {
// This should never happen.
return 0;
}
}
void BinarySemaphore::initSemaphore(uint8_t initCount) {
auto result = sem_init(&handle, true, initCount);
if(result == -1) {
switch(errno) {
case(EINVAL):
// Value exceeds SEM_VALUE_MAX
case(ENOSYS):
// System does not support process-shared semaphores
sif::error << "BinarySemaphore: Init failed with" << strerror(errno)
<< std::endl;
}
}
}
ReturnValue_t BinarySemaphore::checkCount(sem_t* handle, uint8_t maxCount) {
int value = getSemaphoreCounter(handle);
if(value >= maxCount) {
if(maxCount == 1 and value > 1) {
// Binary Semaphore special case.
// This is a config error use lightweight printf is this is called
// from an interrupt
printf("BinarySemaphore::release: Value of binary semaphore greater"
" than 1!\n");
return HasReturnvaluesIF::RETURN_FAILED;
}
return SemaphoreIF::SEMAPHORE_NOT_OWNED;
}
return HasReturnvaluesIF::RETURN_OK;
}