// if create == 0: create new share-memory channel
// else: attach exist share-memory channel and verify data
bus_terminal_channel_t* bus_terminal_channel_init(int32_t shmkey, bus_addr_t from,
bus_addr_t to, size_t size,
int32_t create)
{
struct shm_t* shm;
bus_terminal_channel_t* btc;
size_t alloc_size = size + sizeof(bus_channel_t) + rbuffer_head_size();
// init terminal channel
btc = (bus_terminal_channel_t*)MALLOC(sizeof(*btc));
if (!btc) {
return NULL;
}
// share memory
if (create == 0) {
shm = shm_create(shmkey, alloc_size, 0);
} else {
shm = shm_create(shmkey, alloc_size, 1);
}
if (!shm) {
FREE(btc);
return NULL;
}
// init channel or verify channel data
btc->bc = shm_mem(shm);
assert(btc->bc);
if (create == 0) {
btc->bc->shmkey = shmkey;
btc->bc->from = from;
btc->bc->to = to;
btc->bc->channel_size = size;
} else {
if (btc->bc->shmkey != shmkey || btc->bc->from != from
|| btc->bc->to != to || btc->bc->channel_size != size) {
FREE(btc);
return NULL;
}
}
// init ring buffer
btc->r = rbuffer_init_mem((char*)btc->bc + sizeof(bus_channel_t),
btc->bc->channel_size + rbuffer_head_size());
if (!btc->r) {
FREE(btc);
return NULL;
}
return btc;
}
int32_t _bus_terminal_init_create(bus_terminal_t* bt, int16_t key)
{
int32_t buskey = (key << 16);
struct shm_t* shm = shm_create(buskey, sizeof(bus_t), 0);
if (shm) {
bt->bus = (bus_t*)shm_mem(shm);
assert(bt->bus);
bt->bus->key = buskey;
bt->bus->channel_key = 0;
bt->bus->size = sizeof(bus_t);
// terminals local info
bt->bus->terminal_count = 1;
bt->bus->terminals[0] = bt->self;
atom_set(&bt->bus->terminal_version, 1);
// channels info
bt->bus->channel_count = 0;
atom_set(&bt->bus->channel_version, 1);
return 0;
}
return -1;
}
int32_t _bus_terminal_init_attach(bus_terminal_t* bt, int16_t key)
{
int32_t buskey = (key << 16);
int32_t i;
struct shm_t* shm;
int32_t registered = -1;
// attach exsit shm
shm = shm_create(buskey, sizeof(bus_t), 1);
if (!shm) {
return -1;
}
bt->bus = (bus_t*)shm_mem(shm);
// invalid shm data
if (bt->bus->key != buskey || bt->bus->size != sizeof(bus_t)) {
return -1;
}
// register terminal info
for (i = 0; i < bt->bus->terminal_count; ++ i) {
if (bt->bus->terminals[i] == bt->self) {
registered = 0;
break;
}
}
if (registered != 0) {
if (bt->bus->terminal_count >= BUS_MAX_TERMINAL_COUNT) {
return -1;
} else {
bt->bus->terminals[bt->bus->terminal_count ++] = bt->self;
atom_inc(&bt->bus->terminal_version);
}
}
return 0;
}
