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/*
* Copyright (C) 2015 "IoT.bzh"
* Author "Fulup Ar Foll"
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Reference:
* http://stackoverflow.com/questions/25971505/how-to-delete-element-from-hsearch
*
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <time.h>
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
#include <uuid/uuid.h>
#include <assert.h>
#include "afb-apis.h"
#include "session.h"
#define NOW (time(NULL))
// Session UUID are store in a simple array [for 10 sessions this should be enough]
static struct {
pthread_mutex_t mutex; // declare a mutex to protect hash table
struct AFB_clientCtx **store; // sessions store
int count; // current number of sessions
int max;
int timeout;
int apicount;
const char *initok;
} sessions;
// Free context [XXXX Should be protected again memory abort XXXX]
static void ctxUuidFreeCB (struct AFB_clientCtx *client)
{
int idx;
// If application add a handle let's free it now
assert (client->contexts != NULL);
// Free client handle with a standard Free function, with app callback or ignore it
for (idx=0; idx < sessions.apicount; idx ++) {
if (client->contexts[idx] != NULL) {
afb_apis_free_context(idx, client->contexts[idx]);
client->contexts[idx] = NULL;
}
}
}
// Create a new store in RAM, not that is too small it will be automatically extended
void ctxStoreInit (int nbSession, int timeout, const char *initok)
{
// let's create as store as hashtable does not have any
sessions.store = calloc (1 + (unsigned)nbSession, sizeof(struct AFB_clientCtx));
sessions.max = nbSession;
sessions.timeout = timeout;
sessions.apicount = afb_apis_count();
if (strlen(initok) >= 37) {
fprintf(stderr, "Error: initial token '%s' too long (max length 36)", initok);
exit(1);
}
sessions.initok = initok;
}
static struct AFB_clientCtx *ctxStoreSearch (const char* uuid)
{
int idx;
struct AFB_clientCtx *client;
assert (uuid != NULL);
pthread_mutex_lock(&sessions.mutex);
for (idx=0; idx < sessions.max; idx++) {
client = sessions.store[idx];
if (client && (0 == strcmp (uuid, client->uuid)))
goto found;
}
client = NULL;
found:
pthread_mutex_unlock(&sessions.mutex);
return client;
}
static int ctxStoreDel (struct AFB_clientCtx *client)
{
int idx;
int status;
assert (client != NULL);
pthread_mutex_lock(&sessions.mutex);
for (idx=0; idx < sessions.max; idx++) {
if (sessions.store[idx] == client) {
sessions.store[idx]=NULL;
sessions.count--;
status = 1;
goto deleted;
}
}
status = 0;
deleted:
pthread_mutex_unlock(&sessions.mutex);
return status;
}
static int ctxStoreAdd (struct AFB_clientCtx *client)
{
int idx;
int status;
assert (client != NULL);
//fprintf (stderr, "ctxStoreAdd request uuid=%s count=%d\n", client->uuid, sessions.count);
pthread_mutex_lock(&sessions.mutex);
for (idx=0; idx < sessions.max; idx++) {
if (NULL == sessions.store[idx]) {
sessions.store[idx]= client;
sessions.count++;
status = 1;
goto added;
}
}
status = 0;
added:
pthread_mutex_unlock(&sessions.mutex);
return status;
}
// Check if context timeout or not
static int ctxStoreTooOld (struct AFB_clientCtx *ctx, time_t now)
{
return ctx->expiration <= now;
}
// Loop on every entry and remove old context sessions.hash
static void ctxStoreCleanUp (time_t now)
{
struct AFB_clientCtx *ctx;
long idx;
// Loop on Sessions Table and remove anything that is older than timeout
for (idx=0; idx < sessions.max; idx++) {
ctx = sessions.store[idx];
if (ctx != NULL && ctxStoreTooOld(ctx, now)) {
ctxClientClose (ctx);
}
}
}
// This function will return exiting client context or newly created client context
struct AFB_clientCtx *ctxClientGetForUuid (const char *uuid)
{
uuid_t newuuid;
struct AFB_clientCtx *clientCtx;
time_t now;
/* search for an existing one not too old */
now = NOW;
ctxStoreCleanUp (now);
clientCtx = uuid != NULL ? ctxStoreSearch (uuid) : NULL;
if (clientCtx) {
clientCtx->refcount++;
return clientCtx;
}
/* mimic old behaviour */
if (sessions.initok == NULL)
return NULL;
/* check the uuid if given */
if (uuid != NULL && 1 + strlen(uuid) >= sizeof clientCtx->uuid)
return NULL;
/* returns a new one */
clientCtx = calloc(1, sizeof(struct AFB_clientCtx)); // init NULL clientContext
if (clientCtx != NULL) {
clientCtx->contexts = calloc ((unsigned)sessions.apicount, sizeof (void*));
if (clientCtx->contexts != NULL) {
/* generate the uuid */
if (uuid == NULL) {
uuid_generate(newuuid);
uuid_unparse_lower(newuuid, clientCtx->uuid);
} else {
strcpy(clientCtx->uuid, uuid);
}
strcpy(clientCtx->token, sessions.initok);
clientCtx->expiration = now + sessions.timeout;
clientCtx->refcount = 1;
if (ctxStoreAdd (clientCtx))
return clientCtx;
free(clientCtx->contexts);
}
free(clientCtx);
}
return NULL;
}
struct AFB_clientCtx *ctxClientGet(struct AFB_clientCtx *clientCtx)
{
if (clientCtx != NULL)
clientCtx->refcount++;
return clientCtx;
}
void ctxClientPut(struct AFB_clientCtx *clientCtx)
{
if (clientCtx != NULL) {
assert(clientCtx->refcount != 0);
--clientCtx->refcount;
}
}
// Free Client Session Context
void ctxClientClose (struct AFB_clientCtx *clientCtx)
{
assert(clientCtx != NULL);
if (clientCtx->created) {
clientCtx->created = 0;
ctxUuidFreeCB (clientCtx);
}
if (clientCtx->refcount == 0)
ctxStoreDel (clientCtx);
}
// Sample Generic Ping Debug API
int ctxTokenCheckLen (struct AFB_clientCtx *clientCtx, const char *token, size_t length)
{
assert(clientCtx != NULL);
assert(token != NULL);
// compare current token with previous one
if (ctxStoreTooOld (clientCtx, NOW))
return 0;
if (clientCtx->token[0] && (length >= sizeof(clientCtx->token) || strncmp (token, clientCtx->token, length) || clientCtx->token[length]))
return 0;
clientCtx->created = 1; /* creates by default */
return 1;
}
// Sample Generic Ping Debug API
int ctxTokenCheck (struct AFB_clientCtx *clientCtx, const char *token)
{
assert(clientCtx != NULL);
assert(token != NULL);
return ctxTokenCheckLen(clientCtx, token, strlen(token));
}
// generate a new token and update client context
void ctxTokenNew (struct AFB_clientCtx *clientCtx)
{
uuid_t newuuid;
assert(clientCtx != NULL);
// Old token was valid let's regenerate a new one
uuid_generate(newuuid); // create a new UUID
uuid_unparse_lower(newuuid, clientCtx->token);
// keep track of time for session timeout and further clean up
clientCtx->expiration = NOW + sessions.timeout;
}
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