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Diffstat (limited to 'libexec/talkd/table.c')
| -rw-r--r-- | libexec/talkd/table.c | 233 |
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); +} |
