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-rw-r--r--src/cmdline.c342
1 files changed, 342 insertions, 0 deletions
diff --git a/src/cmdline.c b/src/cmdline.c
new file mode 100644
index 0000000..8974d5b
--- /dev/null
+++ b/src/cmdline.c
@@ -0,0 +1,342 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <time.h>
+#include <errno.h>
+#include <string.h>
+
+#include <sys/ipc.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+
+
+
+#ifdef _SEM_SEMUN_UNDEFINED
+union semun {
+ int val;
+ struct semid_ds *buf;
+ unsigned short *array;
+};
+#endif
+
+
+#define S 0
+#define P 0
+#define Q 1
+
+#define SEMAPHORES 2
+#define MEMORY_SIZE (2 * 1024)
+
+
+char *argv0;
+
+
+static int
+create_semaphores(void)
+{
+ key_t key;
+ int id = -1, saved_errno;
+ union semun values;
+
+ values.array = NULL;
+
+ /* Create semaphore array. */
+ for (;;) {
+ double r = (double)rand();
+ r /= (double)RAND_MAX + 1;
+ r *= (1 << (8 * sizeof(key_t) - 2)) - 1;
+ key = (key_t)r + 1;
+ if (key == IPC_PRIVATE)
+ continue;
+ id = semget(key, SEMAPHORES, IPC_CREAT | IPC_EXCL | 0600);
+ if (id != -1)
+ break;
+ if ((errno != EEXIST) && (errno != EINTR))
+ goto fail;
+ }
+
+ /* Initialise the array. */
+ values.array = calloc(SEMAPHORES, sizeof(unsigned short));
+ if (!values.array)
+ goto fail;
+ if (semctl(id, 0, SETALL, values.array) == -1)
+ goto fail;
+ free(values.array);
+ values.array = NULL;
+
+ printf("key:%zi(x%zx), id:%i\n", (ssize_t)key, (size_t)key, id);
+ return 0;
+
+fail:
+ saved_errno = errno;
+ if ((id != -1) && (semctl(id, 0, IPC_RMID) == -1))
+ perror(argv0);
+ free(values.array);
+ errno = saved_errno;
+ return -1;
+}
+
+
+static int
+create_shared_memory(void)
+{
+ key_t key;
+ int id = -1, saved_errno;
+ struct shmid_ds _info;
+
+ for (;;) {
+ double r = (double)rand();
+ r /= (double)RAND_MAX + 1;
+ r *= (1 << (8 * sizeof(key_t) - 2)) - 1;
+ key = (key_t)r + 1;
+ if (key == IPC_PRIVATE)
+ continue;
+ id = shmget(key, MEMORY_SIZE, IPC_CREAT | IPC_EXCL | 0600);
+ if (id != -1)
+ break;
+ if ((errno != EEXIST) && (errno != EINTR))
+ goto fail;
+ }
+
+ printf("key:%zi(x%zx), id:%i\n", (ssize_t)key, (size_t)key, id);
+ return 0;
+
+fail:
+ saved_errno = errno;
+ if ((id != -1) && (shmctl(id, IPC_RMID, &_info) == -1))
+ perror(argv0);
+ errno = saved_errno;
+ return -1;
+}
+
+
+static int
+remove_semaphores(key_t key)
+{
+ int id = semget(key, SEMAPHORES, 0600);
+
+ if (id == -1)
+ return -1;
+
+ if (semctl(id, 0, IPC_RMID) == -1)
+ return -1;
+
+ return 0;
+}
+
+
+static int
+remove_shared_memory(key_t key)
+{
+ int id = shmget(key, MEMORY_SIZE, 0600);
+ struct shmid_ds _info;
+
+ if (id == -1)
+ return -1;
+
+ if (shmctl(id, IPC_RMID, &_info) == -1)
+ return -1;
+
+ return 0;
+}
+
+
+static int
+acquire_semaphore(key_t key, int semaphore, int delta)
+{
+ struct sembuf op;
+ int id;
+
+ id = semget(key, SEMAPHORES, 0600);
+ if (id == -1)
+ return -1;
+
+ op.sem_op = -delta;
+ op.sem_num = semaphore;
+ op.sem_flg = 0;
+
+ return semop(id, &op, 1);
+}
+
+
+static int
+release_semaphore(key_t key, int semaphore, int delta)
+{
+ struct sembuf op;
+ int id;
+
+ id = semget(key, SEMAPHORES, 0600);
+ if (id == -1)
+ return -1;
+
+ op.sem_op = delta;
+ op.sem_num = semaphore;
+ op.sem_flg = 0;
+
+ return semop(id, &op, 1);
+}
+
+
+static int
+zero_semaphore(key_t key, int semaphore)
+{
+ struct sembuf op;
+ int id;
+
+ id = semget(key, SEMAPHORES, 0600);
+ if (id == -1)
+ return -1;
+
+ op.sem_op = 0;
+ op.sem_num = semaphore;
+ op.sem_flg = 0;
+
+ return semop(id, &op, 1);
+}
+
+
+static int
+read_semaphore(key_t key, int semaphore, int *z, int *n, int *v)
+{
+ struct sembuf op;
+ int id, r;
+
+ id = semget(key, SEMAPHORES, 0600);
+ if (id == -1)
+ return -1;
+
+ if (r = semctl(id, semaphore, GETZCNT), r == -1)
+ return -1;
+ if (z)
+ *z = r;
+
+ if (r = semctl(id, semaphore, GETNCNT), r == -1)
+ return -1;
+ if (n)
+ *n = r;
+
+ if (r = semctl(id, semaphore, GETVAL), r == -1)
+ return -1;
+ if (v)
+ *v = r;
+
+ return 0;
+}
+
+
+static int
+write_shared_memory(key_t key, const char *message)
+{
+ int id, saved_errno;
+ void *address = NULL;
+
+ id = shmget(key, MEMORY_SIZE, 0600);
+ if (id == -1)
+ goto fail;
+
+ address = shmat(id, NULL, 0);
+ if ((address == (void *)-1) || !address)
+ goto fail;
+
+ memcpy(address, message, (strlen(message) + 1) * sizeof(char));
+
+ if (shmdt(address) == -1)
+ goto fail;
+
+ return 0;
+
+fail:
+ saved_errno = errno;
+ if (address && (shmdt(address) == -1))
+ perror(argv0);
+ errno = saved_errno;
+ return -1;
+}
+
+
+static int
+read_shared_memory(key_t key, char *message)
+{
+ int id, saved_errno;
+ void *address = NULL;
+
+ id = shmget(key, MEMORY_SIZE, 0600);
+ if (id == -1)
+ goto fail;
+
+ address = shmat(id, NULL, SHM_RDONLY);
+ if ((address == (void *)-1) || !address)
+ goto fail;
+
+ strncpy(message, address, MEMORY_SIZE);
+
+ if (shmdt(address) == -1)
+ goto fail;
+
+ return 0;
+
+fail:
+ saved_errno = errno;
+ if (address && (shmdt(address) == -1))
+ perror(argv0);
+ errno = saved_errno;
+ return -1;
+}
+
+
+#define t(inst) if (r = inst, r) goto fail
+
+
+int
+main(int argc, char *argv[])
+{
+ int r = -1, saved_errno, value;
+ key_t key_sem = argc > 2 ? (key_t)atoll(argv[2]) : 0;
+ key_t key_shm = argc > 3 ? (key_t)atoll(argv[3]) : 0;
+ const char *message = argc > 4 ? argv[4] : "default message";
+ char read_message[MEMORY_SIZE];
+
+ argv0 = *argv;
+
+ if (!strcmp(argv[1], "create")) {
+ srand(time(NULL));
+ t(create_semaphores());
+ t(create_shared_memory());
+
+ } else if (!strcmp(argv[1], "remove")) {
+ t(remove_semaphores(key_sem));
+ t(remove_shared_memory(key_sem));
+
+ } else if (!strcmp(argv[1], "listen")) { /* TODO must support cancellation */
+ t(release_semaphore(key_sem, S, 1));
+ for (;;) {
+ t(zero_semaphore(key_sem, S));
+ t(read_shared_memory(key_shm, read_message));
+ printf("%s\n", read_message);
+ t(release_semaphore(key_sem, Q, 1));
+ t(zero_semaphore(key_sem, Q));
+ t(release_semaphore(key_sem, S, 1));
+ t(release_semaphore(key_sem, P, 1));
+ }
+
+ } else if (!strcmp(argv[1], "broadcast")) {
+ t(read_semaphore(key_sem, S, &value, NULL, NULL));
+ if (value) {
+ t(write_shared_memory(key_shm, message));
+ t(acquire_semaphore(key_sem, S, value));
+ t(acquire_semaphore(key_sem, Q, value));
+ t(acquire_semaphore(key_sem, P, value));
+ }
+
+ } else
+ return 2;
+
+ return 0;
+
+fail:
+ perror(argv0);
+ return 1;
+}
+
+
+#undef t
+
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-09 17:29:43 +0000