initial commitHEADmain

1 files changed, 114 insertions, 0 deletions

diff --git a/shm.c b/shm.c
new file mode 100644
index 0000000..c20d3c5
--- /dev/null
+++ b/shm.c
@@ -0,0 +1,114 @@
+/*
+ * LOKI3
+ *
+ * [ shm.c ]
+ *
+ *  1996/7 Guild Corporation Worldwide      [daemon9]
+ */
+
+#include "loki.h"
+#include "client_db.h"
+#include "shm.h"
+
+extern struct loki rdg;
+extern int verbose;
+extern int destroy_shm;
+struct client_list *client = 0;
+
+int semid;
+
+
+/*
+ * Obfuscated strings
+ */
+extern estring S_MSG_SHM_DETACH_ERROR;
+extern estring S_MSG_CANNOT_DESTROY_SHMID;
+extern estring S_MSG_CANNOT_DESTROY_SEMAPHORE;
+extern estring S_MSG_SHM_SEGMENT_ERROR;
+extern estring S_MSG_SEMAPHORE_ALLOCATION_ERROR;
+extern estring S_MSG_CANNOT_LOCK_MEMORY;
+extern estring S_MSG_CANNOT_UNLOCK_MEMORY;
+
+/*
+ *  Prepare shared memory and semaphoreg
+ */
+void prep_shm() {
+	key_t shmkey    = SHM_KEY + getpid();  /* shared memory key ID */
+	key_t semkey    = SEM_KEY + getpid();  /* semaphore key ID     */
+	int shmid, len  = sizeof(struct client_list) * MAX_CLIENT;
+
+	/* Request a shared memory segment */
+	if ((shmid = shmget(shmkey, len, IPC_CREAT)) < 0) {
+		err_exit(1, 1, verbose, decrypt(S_MSG_SHM_SEGMENT_ERROR));
+	}
+
+	/* Get SET_SIZE semaphore to perform shared memory locking with */
+	if ((semid = semget(semkey, SET_SIZE, (IPC_CREAT | SHM_PRM))) < 0) {
+		err_exit(1, 1, verbose, decrypt(S_MSG_SEMAPHORE_ALLOCATION_ERROR));
+	}
+
+	/* Attach pointer to the shared memory segment */
+	client = (struct client_list *) shmat(shmid, NULL, 0);
+
+	/* clear the database */
+	for (int i = 0; i < MAX_CLIENT; i++) {
+		bzero(&client[i], sizeof(client[i]));
+	}
+}
+
+
+/*
+ *  Locks the semaphore so the caller can access the shared memory segment.
+ *  This is an atomic operation.
+ */
+void locks() {
+	struct sembuf lock[2] = {
+		{0, 0, 0},
+		{0, 1, SEM_UNDO}
+	};
+
+	if (semop(semid, &lock[0], 2) < 0) {
+		err_exit(1, 1, verbose, decrypt(S_MSG_CANNOT_LOCK_MEMORY));
+	}
+}
+
+
+/*
+ *  Unlocks the semaphore so the caller can access the shared memory segment.
+ *  This is an atomic operation.
+ */
+void ulocks() {
+	struct sembuf ulock[1] = {
+		{ 0, -1, (IPC_NOWAIT | SEM_UNDO) }
+	};
+
+	if (semop(semid, &ulock[0], 1) < 0) {
+		err_exit(1, 1, verbose, decrypt(S_MSG_CANNOT_UNLOCK_MEMORY));
+	}
+}
+
+
+/*
+ *  Release the shared memory segment.
+ */
+void dump_shm() {
+	locks();
+
+	if ((shmdt((uint8_t *)client)) == -1) {
+		err_exit(1, 1, verbose, decrypt(S_MSG_SHM_DETACH_ERROR));
+	}
+
+	if (destroy_shm == OK) {
+		if ((shmctl(semid, IPC_RMID, NULL)) == -1) {
+			err_exit(1, 1, verbose, decrypt(S_MSG_CANNOT_DESTROY_SHMID));
+		}
+
+		if ((semctl(semid, IPC_RMID, 0, NULL)) == -1) {
+			err_exit(1, 1, verbose, decrypt(S_MSG_CANNOT_DESTROY_SEMAPHORE));
+		}
+	}
+
+	ulocks();
+}
+
+/* EOF */