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authorrgrimes <rgrimes@FreeBSD.org>1994-05-27 12:39:25 +0000
committerrgrimes <rgrimes@FreeBSD.org>1994-05-27 12:39:25 +0000
commit7d07d2de2f52d4e2eba169e5563165309a795128 (patch)
treec3590f60f61233b4a571cfe3bfc08f6ab6591c88 /libexec/talkd/table.c
parentf9ab90d9d6d02989a075d0f0074496d5b1045e4b (diff)
downloadFreeBSD-src-7d07d2de2f52d4e2eba169e5563165309a795128.zip
FreeBSD-src-7d07d2de2f52d4e2eba169e5563165309a795128.tar.gz
BSD 4.4 Lite Libexec Sources
Diffstat (limited to 'libexec/talkd/table.c')
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diff --git a/libexec/talkd/table.c b/libexec/talkd/table.c
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+/*
+ * 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);
+}
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