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/* hey emacs! -*- Mode: C; c-file-style: "k&r"; indent-tabs-mode: nil -*- */
/*
* tftpd_list.c
* thread_data and client list related functions
*
* $Id: tftpd_list.c,v 1.9 2004/02/27 02:05:26 jp Exp $
*
* Copyright (c) 2000 Jean-Pierre Lefebvre <helix@step.polymtl.ca>
* and Remi Lefebvre <remi@debian.org>
*
* atftp is free software; you can redistribute them and/or modify them
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include "tftpd.h"
#include "logger.h"
/*
* thread_data is a double link list of server threads. Server threads
* are started by the main thread when a new request arrives. The number
* of threads running is held in number_of_thread. Any access to the
* thread_data list: insertion and extraction of elements must be protected
* by the mutex. This is done in this file by all functions playing with the thread list.
* Note that individual threads do not need to lock the list when playing in their data.
* See tftpd.h.
*
* In addition, it is needed to use mutex when working on the client list of
* individual thread. In some case, the thread data mutex is needed also.
* Again, the functions in this file take care of this.
*/
struct thread_data *thread_data = NULL; /* head of thread list */
static int number_of_thread = 0;
pthread_mutex_t thread_list_mutex = PTHREAD_MUTEX_INITIALIZER;
/*
* Add a new thread_data structure to the list. Thread list mutex is locked
* before walking the list and doing the insertion.
*/
int tftpd_list_add(struct thread_data *new)
{
struct thread_data *current = thread_data;
int ret;
pthread_mutex_lock(&thread_list_mutex);
number_of_thread++;
ret = number_of_thread;
if (thread_data == NULL)
{
thread_data = new;
new->prev = NULL;
new->next = NULL;
}
else
{
while (current->next != NULL)
current = current->next;
current->next = new;
new->prev = current;
new->next = NULL;
}
pthread_mutex_unlock(&thread_list_mutex);
return ret;
}
/*
* Remove a thread_data structure from the list.
*/
int tftpd_list_remove(struct thread_data *old)
{
struct thread_data *current = thread_data;
int ret;
pthread_mutex_lock(&thread_list_mutex);
number_of_thread--;
ret = number_of_thread;
if (thread_data == old)
{
if (thread_data->next != NULL)
{
thread_data = thread_data->next;
thread_data->prev = NULL;
}
else
thread_data = NULL;
}
else
{
while (current != old)
current = current->next;
if (current->next && current->prev)
{
current->prev->next = current->next;
current->next->prev = current->prev;
}
else
current->prev->next = NULL;
}
pthread_mutex_unlock(&thread_list_mutex);
return ret;
}
/*
* Return the number of threads actually started.
*/
int tftpd_list_num_of_thread(void)
{
int ret;
pthread_mutex_lock(&thread_list_mutex);
ret = number_of_thread;
pthread_mutex_unlock(&thread_list_mutex);
return ret;
}
/*
* This function looks for a thread serving exactly the same
* file and with the same options as another client. This implies a
* multicast enabled client.
*/
int tftpd_list_find_multicast_server_and_add(struct thread_data **thread,
struct thread_data *data,
struct client_info *client)
{
struct thread_data *current = thread_data; /* head of the list */
struct tftp_opt *tftp_options = data->tftp_options;
struct client_info *tmp;
char options[MAXLEN];
char string[MAXLEN];
char *index;
int len;
*thread = NULL;
opt_request_to_string(tftp_options, options, MAXLEN);
index = strstr(options, "multicast");
len = (int)index - (int)options;
/* lock the whole list before walking it */
pthread_mutex_lock(&thread_list_mutex);
while (current)
{
if (current != data)
{
/* Lock the client list before reading client ready state */
pthread_mutex_lock(¤t->client_mutex);
if (current->client_ready == 1)
{
opt_request_to_string(current->tftp_options, string, MAXLEN);
/* must have exact same option string */
if (strncmp(string, options, len) == 0)
{
*thread = current;
/* insert the new client at the end. If the client is already
in the list, don't add it again. */
tmp = current->client_info;
while (1)
{
if ((tmp->client.sin_port == client->client.sin_port) &&
(tmp->client.sin_addr.s_addr == client->client.sin_addr.s_addr) &&
(tmp->done == 0))
{
/* unlock mutex and exit */
pthread_mutex_unlock(¤t->client_mutex);
pthread_mutex_unlock(&thread_list_mutex);
return 2;
}
if (tmp->next == NULL)
break;
tmp = tmp->next;
}
tmp->next = client;
/* unlock mutex and exit */
pthread_mutex_unlock(¤t->client_mutex);
pthread_mutex_unlock(&thread_list_mutex);
return 1;
}
}
pthread_mutex_unlock(¤t->client_mutex);
}
current = current->next;
}
pthread_mutex_unlock(&thread_list_mutex);
return 0;
}
inline void tftpd_clientlist_ready(struct thread_data *thread)
{
pthread_mutex_lock(&thread->client_mutex);
thread->client_ready = 1;
pthread_mutex_unlock(&thread->client_mutex);
}
/*
* As of the the above comment, we never remove the head element.
*/
void tftpd_clientlist_remove(struct thread_data *thread,
struct client_info *client)
{
struct client_info *tmp = thread->client_info;
pthread_mutex_lock(&thread->client_mutex);
while ((tmp->next != client) && (tmp->next != NULL))
tmp = tmp->next;
if (tmp->next == NULL)
return;
tmp->next = tmp->next->next;
pthread_mutex_unlock(&thread->client_mutex);
}
/*
* Free all allocated client structure.
*/
void tftpd_clientlist_free(struct thread_data *thread)
{
struct client_info *tmp;
struct client_info *head = thread->client_info;
pthread_mutex_lock(&thread->client_mutex);
while (head)
{
tmp = head;
head = head->next;
free(tmp);
}
pthread_mutex_unlock(&thread->client_mutex);
}
/*
* Mark a client as done
*/
int tftpd_clientlist_done(struct thread_data *thread,
struct client_info *client,
struct sockaddr_in *sock)
{
struct client_info *head = thread->client_info;
pthread_mutex_lock(&thread->client_mutex);
if (client)
{
client->done = 1;
pthread_mutex_unlock(&thread->client_mutex);
return 1;
}
if (sock)
{
/* walk the list to find this client */
while (head)
{
if (memcmp(sock, &head->client, sizeof(struct sockaddr_in)) == 0)
{
head->done = 1;
pthread_mutex_unlock(&thread->client_mutex);
return 1;
}
else
head = head->next;
}
}
pthread_mutex_unlock(&thread->client_mutex);
return 0;
}
/*
* Return the next client in the list.
* If a client is found, *client got the address and return 1.
* If no more client are available, 0 is returned and client_ready is unset
* If the new client is the same, -1 is returned.
*
* List is search from the current client address and wrap around.
*/
int tftpd_clientlist_next(struct thread_data *thread,
struct client_info **client)
{
struct client_info *tmp;
pthread_mutex_lock(&thread->client_mutex);
/* If there's a next, start with it. Else search from the
beginning */
if ((*client)->next)
tmp = (*client)->next;
else
tmp = thread->client_info;
/* search from the current client */
while (tmp)
{
if (!tmp->done)
{
/* If this is the same as *client */
if (tmp == *client)
{
pthread_mutex_unlock(&thread->client_mutex);
return -1;
}
*client = tmp;
pthread_mutex_unlock(&thread->client_mutex);
return 1;
}
tmp = tmp->next;
/* if no more entry, start at begining */
if (tmp == NULL)
tmp = thread->client_info;
/* if we fall back on the current client, there is no more
client to serve */
if (tmp == *client)
tmp = NULL;
}
/* There is no more client to server */
thread->client_ready = 0;
*client = NULL;
pthread_mutex_unlock(&thread->client_mutex);
return 0;
}
void tftpd_list_kill_threads(void)
{
struct thread_data *current = thread_data; /* head of list */
pthread_mutex_lock(&thread_list_mutex);
while (current != NULL)
{
pthread_kill(current->tid, SIGTERM);
current = current->next;
}
pthread_mutex_unlock(&thread_list_mutex);
}
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