BSD 4.4 Lite Libexec Sources

1 files changed, 233 insertions, 0 deletions

diff --git a/libexec/talkd/table.c b/libexec/talkd/table.c
new file mode 100644
index 0000000..cc8cb66
--- /dev/null
+++ b/libexec/talkd/table.c
@@ -0,0 +1,233 @@
+/*
+ * Copyright (c) 1983, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+static char sccsid[] = "@(#)table.c	8.1 (Berkeley) 6/4/93";
+#endif /* not lint */
+
+/*
+ * Routines to handle insertion, deletion, etc on the table
+ * of requests kept by the daemon. Nothing fancy here, linear
+ * search on a double-linked list. A time is kept with each 
+ * entry so that overly old invitations can be eliminated.
+ *
+ * Consider this a mis-guided attempt at modularity
+ */
+#include <sys/param.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <protocols/talkd.h>
+#include <syslog.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define MAX_ID 16000	/* << 2^15 so I don't have sign troubles */
+
+#define NIL ((TABLE_ENTRY *)0)
+
+extern	int debug;
+struct	timeval tp;
+struct	timezone txp;
+
+typedef struct table_entry TABLE_ENTRY;
+
+struct table_entry {
+	CTL_MSG request;
+	long	time;
+	TABLE_ENTRY *next;
+	TABLE_ENTRY *last;
+};
+
+TABLE_ENTRY *table = NIL;
+CTL_MSG *find_request();
+CTL_MSG *find_match();
+
+/*
+ * Look in the table for an invitation that matches the current
+ * request looking for an invitation
+ */
+CTL_MSG *
+find_match(request)
+	register CTL_MSG *request;
+{
+	register TABLE_ENTRY *ptr;
+	time_t current_time;
+
+	gettimeofday(&tp, &txp);
+	current_time = tp.tv_sec;
+	if (debug)
+		print_request("find_match", request);
+	for (ptr = table; ptr != NIL; ptr = ptr->next) {
+		if ((ptr->time - current_time) > MAX_LIFE) {
+			/* the entry is too old */
+			if (debug)
+				print_request("deleting expired entry",
+				    &ptr->request);
+			delete(ptr);
+			continue;
+		}
+		if (debug)
+			print_request("", &ptr->request);
+		if (strcmp(request->l_name, ptr->request.r_name) == 0 &&
+		    strcmp(request->r_name, ptr->request.l_name) == 0 &&
+		     ptr->request.type == LEAVE_INVITE)
+			return (&ptr->request);
+	}
+	return ((CTL_MSG *)0);
+}
+
+/*
+ * Look for an identical request, as opposed to a complimentary
+ * one as find_match does 
+ */
+CTL_MSG *
+find_request(request)
+	register CTL_MSG *request;
+{
+	register TABLE_ENTRY *ptr;
+	time_t current_time;
+
+	gettimeofday(&tp, &txp);
+	current_time = tp.tv_sec;
+	/*
+	 * See if this is a repeated message, and check for
+	 * out of date entries in the table while we are it.
+	 */
+	if (debug)
+		print_request("find_request", request);
+	for (ptr = table; ptr != NIL; ptr = ptr->next) {
+		if ((ptr->time - current_time) > MAX_LIFE) {
+			/* the entry is too old */
+			if (debug)
+				print_request("deleting expired entry",
+				    &ptr->request);
+			delete(ptr);
+			continue;
+		}
+		if (debug)
+			print_request("", &ptr->request);
+		if (strcmp(request->r_name, ptr->request.r_name) == 0 &&
+		    strcmp(request->l_name, ptr->request.l_name) == 0 &&
+		    request->type == ptr->request.type &&
+		    request->pid == ptr->request.pid) {
+			/* update the time if we 'touch' it */
+			ptr->time = current_time;
+			return (&ptr->request);
+		}
+	}
+	return ((CTL_MSG *)0);
+}
+
+insert_table(request, response)
+	CTL_MSG *request;
+	CTL_RESPONSE *response;
+{
+	register TABLE_ENTRY *ptr;
+	time_t current_time;
+
+	gettimeofday(&tp, &txp);
+	current_time = tp.tv_sec;
+	request->id_num = new_id();
+	response->id_num = htonl(request->id_num);
+	/* insert a new entry into the top of the list */
+	ptr = (TABLE_ENTRY *)malloc(sizeof(TABLE_ENTRY));
+	if (ptr == NIL) {
+		syslog(LOG_ERR, "insert_table: Out of memory");
+		_exit(1);
+	}
+	ptr->time = current_time;
+	ptr->request = *request;
+	ptr->next = table;
+	if (ptr->next != NIL)
+		ptr->next->last = ptr;
+	ptr->last = NIL;
+	table = ptr;
+}
+
+/*
+ * Generate a unique non-zero sequence number
+ */
+new_id()
+{
+	static int current_id = 0;
+
+	current_id = (current_id + 1) % MAX_ID;
+	/* 0 is reserved, helps to pick up bugs */
+	if (current_id == 0)
+		current_id = 1;
+	return (current_id);
+}
+
+/*
+ * Delete the invitation with id 'id_num'
+ */
+delete_invite(id_num)
+	int id_num;
+{
+	register TABLE_ENTRY *ptr;
+
+	ptr = table;
+	if (debug)
+		syslog(LOG_DEBUG, "delete_invite(%d)", id_num);
+	for (ptr = table; ptr != NIL; ptr = ptr->next) {
+		if (ptr->request.id_num == id_num)
+			break;
+		if (debug)
+			print_request("", &ptr->request);
+	}
+	if (ptr != NIL) {
+		delete(ptr);
+		return (SUCCESS);
+	}
+	return (NOT_HERE);
+}
+
+/*
+ * Classic delete from a double-linked list
+ */
+delete(ptr)
+	register TABLE_ENTRY *ptr;
+{
+
+	if (debug)
+		print_request("delete", &ptr->request);
+	if (table == ptr)
+		table = ptr->next;
+	else if (ptr->last != NIL)
+		ptr->last->next = ptr->next;
+	if (ptr->next != NIL)
+		ptr->next->last = ptr->last;
+	free((char *)ptr);
+}