void shm_init() {
sem_t* sem = auv_shm_lock();
bool create = false;
// Check if the shm block is valid.
int shmid = auv_shm_open(sizeof(struct shm_header), 0666);
if (shmid >= 0) {
struct shm_header* header = (struct shm_header*)shmat(shmid, 0, 0);
bool checksum = strcmp(header->checksum, SHM_CHECKSUM) == 0;
bool empty = shm_header_empty(header);
shmdt(header);
if (!checksum) {
if (empty) {
shm_rm(shmid);
create = true;
} else {
sem_post(sem);
puts("shm versions do not match. Please restart all shm clients.");
abort();
}
}
} else {
create = true;
}
// Connect to shared memory.
shmid = auv_shm_open(sizeof(struct shm), IPC_CREAT|0666);
shm = (struct shm*)shmat(shmid, 0, 0);
if (shm <= 0) {
shm_rm(shmid);
sem_post(sem);
puts("Failed to connect to shared memory.");
abort();
}
// Initialize everything if we created a new file.
if (create) {
shm_init_vars();
}
// Mark ourselves as using the shm file.
connect(&shm->header);
sem_post(sem);
}
static void shm_close(void *addr)
{
shm_detach(addr);
shm_rm();
}
int main()
{
int bufferFilledSpaces, bufferEmptySpaces, semM, semN;
char *buffer;
int temp;
int shmid;
char c1, c2;
int input = 0;
int counter;
char *arg[1] = {0};
int N;
// Create duplicate process and give it code from ProcN
N = fork();
if (N == 0) // process is a child
{
execv("ProcN", arg);
}
// Create semaphore bufferFilledSpaces
bufferFilledSpaces = sem_create(155555, 0);
if (bufferFilledSpaces < 0)
{
Error(1); // Error has occurred
}
// Create semaphore bufferEmptySpaces
bufferEmptySpaces = sem_create(255555, 1);
if (bufferEmptySpaces < 0)
{
Error(1); // Error has occurred
}
// Creates synchronization semaphores
semM = sem_create(355555, 0);
if (semM < 0)
{
Error(1); // Error has occurred
}
// Creates synchronization semaphores
semN = sem_create(455555, 0);
if (semN < 0)
{
Error(1); // Error has occurred
}
// Opens shared memory between two processes
shmid = shm_get(123123, (void*) &buffer, 90);
// Synchronization with Process N
temp = sem_signal(semN);
temp = sem_wait(semM);
// Part 1 - Fill in initial values
c1 = 'a';
c2 = '0';
counter = 1;
while (counter <= 260)
{
temp = sem_wait(bufferEmptySpaces);
buffer[input] = c1;
buffer[input+1] = c2;
buffer[input+2] = c1;
//Debug
//printf("# %c%c%c #", c1, c2, c1);
if ((counter % 26) == 0) // Increment number if needed
{
c2++;
c1 = 'a';
}
else // Otherwise, move to next letter in alphabet
{
c1++;
}
counter++;
temp = sem_signal(bufferFilledSpaces);
}
// Part 2 - Fill in initial values
c1 = 'A';
c2 = '0';
counter = 1;
while (counter <= 260)
{
temp = sem_wait(bufferEmptySpaces);
buffer[input] = c1;
buffer[input+1] = c2;
buffer[input+2] = c1;
//Debug
//printf("# %c%c%c #", c1, c2, c1);
if ((counter % 26) == 0) // Increment number if needed
{
c2++;
c1 = 'A';
}
else // Otherwise, move to next letter in alphabet
{
c1++;
}
counter++;
temp = sem_signal(bufferFilledSpaces);
}
// Synchronization with Process N
temp = sem_signal(semN);
temp = sem_wait(semM);
// Remove semaphores
temp = sem_rm(bufferEmptySpaces);
temp = sem_rm(bufferFilledSpaces);
temp = sem_rm(semM);
temp = sem_rm(semN);
// Remove shared memory
temp = shm_rm(shmid);
printf("\n");
return 1;
}
int main()
{
int *BufferA;
int *BufferB;
char c1, c2, c3;
int bufAFilled, bufAEmpty, bufBFilled, bufBEmpty;
int semX, semY, semZ, CSX, CSY, CSZ;
int pX, pY;
char *arg[1] = {0};
int shmid1, shmid2;
int temp, loop_finished, counter, input;
// Create semaphore bufAFilled
bufAFilled = sem_create(500001, 0);
if (bufAFilled < 0)
{
Error(1); // Error has occurred
}
// Create semaphore bufAEmpty
bufAEmpty = sem_create(500002, 11);
if (bufAEmpty < 0)
{
Error(1); // Error has occurred
}
// Create semaphore bufBFilled
bufBFilled = sem_create(500003, 0);
if (bufBFilled < 0)
{
Error(1); // Error has occurred
}
// Create semaphore bufBEmpty
bufBEmpty = sem_create(500004, 23);
if (bufBEmpty < 0)
{
Error(1); // Error has occurred
}
// Create semaphore semX
semX = sem_create(500005, 0);
if (semX < 0)
{
Error(1); // Error has occurred
}
// Create semaphore semY
semY = sem_create(500006, 0);
if (semY < 0)
{
Error(1); // Error has occurred
}
// Create semaphore semZ
semZ = sem_create(500007, 0);
if (semZ < 0)
{
Error(1); // Error has occurred
}
// Create semaphore CSX
CSX = sem_create(500008, 0);
if (CSX < 0)
{
Error(1); // Error has occurred
}
// Create semaphore CSY
CSY = sem_create(500009, 0);
if (CSY < 0)
{
Error(1); // Error has occurred
}
// Create semaphore CSZ
CSZ = sem_create(500010, 0);
if (CSZ < 0)
{
Error(1); // Error has occurred
}
// Opens shared memory between two processes
shmid1 = shm_get(900001, (void*) &BufferA, 22);
// Opens shared memory between two processes
shmid2 = shm_get(900002, (void*) &BufferB, 69);
// Create duplicate processes and give them code for processes X and Y
pX = fork();
if (pX == 0) // process is a child
{
execv("ProcX", arg);
}
pY = fork();
if (pY == 0) // process is a child
{
execv("ProcY", arg);
}
// Synchronize with ProcX and ProcY
temp = sem_signal(semX);
temp = sem_signal(semY);
temp = sem_wait(semZ);
temp = sem_wait(semZ);
// Take out items from buffers when elements exist
counter = 1;
input = 0;
while (counter <= 260)
{
// Wait until both of the buffers have been filled
temp = sem_wait(CSZ);
temp = sem_wait(CSZ);
// Remove one item from BufferA when one exists
temp = sem_wait(bufAFilled);
c1 = BufferA[input*2];
c2 = BufferA[input*2+1];
printf("+ %c%c +", c1, c2);
temp = sem_signal(bufAEmpty);
// Remove one item from BufferB when one exists
temp = sem_wait(bufBFilled);
c1 = BufferB[input*3];
c2 = BufferB[input*3+1];
c3 = BufferB[input*3+2];
printf("+ %c%c%c +", c1, c2, c3);
temp = sem_signal(bufBEmpty);
if ((counter % 160) == 0) // Sleep after taking every 160 items
{
// printf("-!Sleeping 3 seconds!-");
// sleep(3);
}
counter++;
// Signal the commencement of the filling both the buffers
temp = sem_signal(CSX);
temp = sem_signal(CSY);
}
// Synchronize with ProcX and ProcY
temp = sem_signal(semX);
temp = sem_signal(semY);
temp = sem_wait(semZ);
temp = sem_wait(semZ);
// sleep(7);
printf("\n");
// Remove semaphores
temp = sem_rm(bufAEmpty);
temp = sem_rm(bufAFilled);
temp = sem_rm(bufBEmpty);
temp = sem_rm(bufBFilled);
temp = sem_rm(semX);
temp = sem_rm(semY);
temp = sem_rm(semZ);
temp = sem_rm(CSX);
temp = sem_rm(CSY);
temp = sem_rm(CSZ);
// Remove shared memory
temp = shm_rm(shmid1);
temp = shm_rm(shmid2);
printf("\nProcZ: Exiting...\n");
return 1;
}
