C SIGSEGV Handler & Mprotect
- by pws5068
I'm constructing a program which uses mprotect() to restrict a block of memory from accessing. When the memory is requested, a SIGSEGV is thrown which I listen for using a signal() call.
Once the SIGSEGV has been detected, I need to somehow access the pointer to the memory that was requested (that threw the fault) and the size of the segment requested. Is this possible?
void fifoSigHandler(){
// Needs to only remove protection from requested block of virtual memory
mprotect(fifoVm,(size_t)fifoVm_size,PROT_WRITE);
printf("Caught Seg Fault");
}
void fifo_init(void* vm, int vm_size, int n_frames, int page_size)
{
fifoVm = vm;
fifoVm_size = vm_size;
fifoFrames = n_frames;
fifoPageSize = page_size;
mprotect(fifoVm,(size_t)fifoVm_size,PROT_NONE);
signal(SIGSEGV, fifoSigHandler);
}
Additionally, is there a way to determine the level of mprotect() a block of memory is currently assigned (PROT_NONE,PROT_READ, etc..)?
