int XXp1(char *arg)
{
int i, pid[10], result[10];
printf("XXp1(): creating children\n");
for (i = 0; i < 3; i++)
pid[i] = fork1("XXp2", XXp2, "XXp2", USLOSS_MIN_STACK, 3);
printf("XXp1(): creating zapper child\n");
pid[i] = fork1("XXp3", XXp3, "XXp3", USLOSS_MIN_STACK, 4);
printf("XXp1(): unblocking children\n");
for (i = 0; i < 3; i++)
result[i] = unblockProc(pid[i]);
for (i = 0; i < 3; i++)
printf("XXp1(): after unblocking %d, result = %d\n", pid[i], result[i]);
quit(0);
return 0;
} /* XXp1 */
// returns 0 if nothing unblocked
// returns 1 if something was unblocked
int unblock(int mboxID, int block, int size, char message[], int *realSize) {
// multiple processes may be blocked on the same mailbox, we only want to unblock one of them
// this keeps track of it. Start at -1 incase no one is blocked on that mailbox
int unblockID = -1;
// go through the entire proc list and find the process to be unblocked
for (int i = 0; i < MAXPROC; i++) {
// find a process blocked on this mailbox and make sure they are the same type of block
if (processTable[i].mboxID == mboxID && processTable[i].blockStatus == block) {
// if this is the first process to be found
if (unblockID == -1) {
// set the unblockid to this new processes index in the table
unblockID = i;
}
// otherwise
else {
// compare the start times of the old process and this new found one
if (processTable[unblockID].timeAdded > processTable[i].timeAdded) {
// if the new found process was blocked before the last found process, swap
unblockID = i;
}
}
}
}
// check to see if anyone needs to be unblocked
if (unblockID != -1) {
// save their pid
int pid = processTable[unblockID].pid;
// check if a receiver wants to get a message thats too big
int retVal = 1;
if (block == RECEIVEBLOCK && size > processTable[unblockID].size) {
retVal++;
}
// if a zero slot message box
if (message != NULL && block == SENDBLOCK) {
memcpy(message, processTable[unblockID].message, size);
*realSize = processTable[unblockID].size;
}
else if (message != NULL && block == RECEIVEBLOCK) {
memcpy(processTable[unblockID].message, message, size);
processTable[unblockID].size = size;
}
if (block == SENDBLOCK) {
// empty out this slot in the processTable
processTable[unblockID].pid = -1;
processTable[unblockID].blockStatus = -1;
processTable[unblockID].message[0] = '\0';
processTable[unblockID].size = -1;
processTable[unblockID].mboxID = -1;
processTable[unblockID].timeAdded = -1;
}
// unblock the process
unblockProc(pid);
return retVal;
}
else {
return 0;
}
}
int MboxRelease(int mailboxID) {
check_kernel_mode("MboxRelease");
disableInterrupts();
// get the mailbox
mailbox *mbox = &(MailBoxTable[mailboxID]);
// check to make sure the mail box is in use
if (mbox->mboxID == -1) {
return -1;
}
// update that this mail box is about to be deleted
MailBoxTable[mailboxID].mboxID = -1;
// unblock all processes blocked on this mailbox
int unblockID = -1; // the index of the proccess to unblock
// go through the entire proc list and find the process to be unblocked
for (int i = 0; i < MAXPROC; i++) {
// find a process blocked on this mailbox
if (processTable[i].mboxID == mailboxID) {
// if this is the first process to be found
if (unblockID == -1) {
// set the unblockid to this new processes index in the table
unblockID = i;
}
// otherwise
else {
// compare the start times of the old process and this new found one
if (processTable[unblockID].timeAdded > processTable[i].timeAdded) {
// if the new found process was blocked before the last found process, swap
unblockID = i;
}
}
}
}
// if a blocked person was found, release them
if (unblockID != -1) {
unblockProc(processTable[unblockID].pid);
// remove their info from the procTable
processTable[unblockID].pid = -1;
processTable[unblockID].blockStatus = NOT_BLOCKED;
processTable[unblockID].message[0] = '\0';
processTable[unblockID].size = -1;
processTable[unblockID].mboxID = -1;
processTable[unblockID].timeAdded = -1;
}
// if there are still more processes to be unblocked
while (unblockID != -1) {
// set unblockID back to -1;
unblockID = -1;
// go through the entire proc list and find the process to be unblocked
for (int i = 0; i < MAXPROC; i++) {
// find a process blocked on this mailbox
if (processTable[i].mboxID == mailboxID) {
// if this is the first process to be found
if (unblockID == -1) {
// set the unblockid to this new processes index in the table
unblockID = i;
}
// otherwise
else {
// compare the start times of the old process and this new found one
if (processTable[unblockID].timeAdded > processTable[i].timeAdded) {
// if the new found process was blocked before the last found process, swap
unblockID = i;
}
}
}
}
// if a blocked person was found, release them
if (unblockID != -1) {
unblockProc(processTable[unblockID].pid);
// remove their info from the procTable
processTable[unblockID].pid = -1;
processTable[unblockID].blockStatus = NOT_BLOCKED;
processTable[unblockID].message[0] = '\0';
processTable[unblockID].size = -1;
processTable[unblockID].mboxID = -1;
processTable[unblockID].timeAdded = -1;
}
}
// null out all slots used by the mailbox
slotPtr pre = NULL;
slotPtr slot = mbox->headPtr;
while (slot != NULL) {
slot->mboxID = -1;
slot->status = -1;
slot->message[0] = '\0';
slot->size = -1;
if (pre != NULL) {
pre->nextSlot = NULL;
}
pre = slot;
slot = slot->nextSlot;
}
// null out the removed mailbox
MailBoxTable[mailboxID].mboxID = -1;
MailBoxTable[mailboxID].numSlots = -1;
MailBoxTable[mailboxID].numSlotsUsed = -1;
MailBoxTable[mailboxID].slotSize = -1;
MailBoxTable[mailboxID].headPtr = NULL;
MailBoxTable[mailboxID].endPtr = NULL;
MailBoxTable[mailboxID].blockStatus = 1;
// check if zapped
if (isZapped()) {
return -3;
}
enableInterrupts();
return 0;
}
