/*
* Copyright (C) 2006 Ondrej Palkovsky
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/** @addtogroup libc
* @{
*/
/** @file
*/
/**
* Asynchronous library
*
* The aim of this library is facilitating writing programs utilizing
* the asynchronous nature of Helenos IPC, yet using a normal way
* of programming.
*
* You should be able to write very simple multithreaded programs,
* the async framework will automatically take care of most synchronization
* problems.
*
* Default semantics:
* - send() - send asynchronously. If the kernel refuses to send more
* messages, [ try to get responses from kernel, if nothing
* found, might try synchronous ]
*
* Example of use:
*
* 1) Multithreaded client application
* create_thread(thread1);
* create_thread(thread2);
* ...
*
* thread1() {
* conn = ipc_connect_me_to();
* c1 = send(conn);
* c2 = send(conn);
* wait_for(c1);
* wait_for(c2);
* }
*
*
* 2) Multithreaded server application
* main() {
* async_manager();
* }
*
*
* client_connection(icallid, *icall) {
* if (want_refuse) {
* ipc_answer_fast(icallid, ELIMIT, 0, 0);
* return;
* }
* ipc_answer_fast(icallid, 0, 0, 0);
*
* callid = async_get_call(&call);
* handle(callid, call);
* ipc_answer_fast(callid, 1,2,3);
*
* callid = async_get_call(&call);
* ....
* }
*
* TODO: Detaching/joining dead psthreads?
*/
#include <futex.h>
#include <async.h>
#include <psthread.h>
#include <stdio.h>
#include <libadt/hash_table.h>
#include <libadt/list.h>
#include <ipc/ipc.h>
#include <assert.h>
#include <errno.h>
#include <time.h>
#include <arch/barrier.h>
atomic_t async_futex = FUTEX_INITIALIZER;
static hash_table_t conn_hash_table;
static LIST_INITIALIZE(timeout_list);
typedef struct {
struct timeval expires; /**< Expiration time for waiting thread */
int inlist; /**< If true, this struct is in timeout list */
link_t link;
pstid_t ptid; /**< Thread waiting for this message */
int active; /**< If this thread is currently active */
int timedout; /**< If true, we timed out */
} awaiter_t;
typedef struct {
awaiter_t wdata;
int done; /**< If reply was received */
ipc_call_t *dataptr; /**< Pointer where the answer data
* is stored */
ipcarg_t retval;
} amsg_t;
typedef struct {
link_t link;
ipc_callid_t callid;
ipc_call_t call;
} msg_t;
typedef struct {
awaiter_t wdata;
link_t link; /**< Hash table link */
ipcarg_t in_phone_hash; /**< Incoming phone hash. */
link_t msg_queue; /**< Messages that should be delivered to this thread */
/* Structures for connection opening packet */
ipc_callid_t callid;
ipc_call_t call;
ipc_callid_t close_callid; /* Identification of closing packet */
void (*cthread)(ipc_callid_t,ipc_call_t *);
} connection_t;
/** Identifier of incoming connection handled by current thread */
__thread connection_t *PS_connection;
/** If true, it is forbidden to use async_req functions and
* all preemption is disabled */
__thread int in_interrupt_handler;
static void default_client_connection(ipc_callid_t callid, ipc_call_t *call);
static void default_interrupt_received(ipc_callid_t callid, ipc_call_t *call);
static async_client_conn_t client_connection = default_client_connection;
static async_client_conn_t interrupt_received = default_interrupt_received;
/** Add microseconds to give timeval */
static void tv_add(struct timeval *tv, suseconds_t usecs)
{
tv->tv_sec += usecs / 1000000;
tv->tv_usec += usecs % 1000000;
if (tv->tv_usec > 1000000) {
tv->tv_sec++;
tv->tv_usec -= 1000000;
}
}
/** Subtract 2 timevals, return microseconds difference */
static suseconds_t tv_sub(struct timeval *tv1, struct timeval *tv2)
{
suseconds_t result;
result = tv1->tv_usec - tv2->tv_usec;
result += (tv1->tv_sec - tv2->tv_sec) * 1000000;
return result;
}
/** Compare timeval
*
* @return 1 if tv1 > tv2, otherwise 0
*/
static int tv_gt(struct timeval *tv1, struct timeval *tv2)
{
if (tv1->tv_sec > tv2->tv_sec)
return 1;
if (tv1->tv_sec == tv2->tv_sec && tv1->tv_usec > tv2->tv_usec)
return 1;
return 0;
}
static int tv_gteq(struct timeval *tv1, struct timeval *tv2)
{
if (tv1->tv_sec > tv2->tv_sec)
return 1;
if (tv1->tv_sec == tv2->tv_sec && tv1->tv_usec >= tv2->tv_usec)
return 1;
return 0;
}
/* Hash table functions */
#define CONN_HASH_TABLE_CHAINS 32
static hash_index_t conn_hash(unsigned long *key)
{
return ((*key) >> 4) % CONN_HASH_TABLE_CHAINS;
}
static int conn_compare(unsigned long key[], hash_count_t keys, link_t *item)
{
connection_t *hs;
hs = hash_table_get_instance(item, connection_t, link);
return key[0] == hs->in_phone_hash;
}
static void conn_remove(link_t *item)
{
free(hash_table_get_instance
(item
, connection_t
, link
)); }
/** Operations for NS hash table. */
static hash_table_operations_t conn_hash_table_ops = {
.hash = conn_hash,
.compare = conn_compare,
.remove_callback = conn_remove
};
/** Insert sort timeout msg into timeouts list
*
*/
static void insert_timeout(awaiter_t *wd)
{
link_t *tmp;
awaiter_t *cur;
wd->timedout = 0;
wd->inlist = 1;
tmp = timeout_list.next;
while (tmp != &timeout_list) {
cur = list_get_instance(tmp, awaiter_t, link);
if (tv_gteq(&cur->expires, &wd->expires))
break;
tmp = tmp->next;
}
list_append(&wd->link, tmp);
}
/*************************************************/
/** Try to route a call to an appropriate connection thread
*
*/
static int route_call(ipc_callid_t callid, ipc_call_t *call)
{
connection_t *conn;
msg_t *msg;
link_t *hlp;
unsigned long key;
futex_down(&async_futex);
key = call->in_phone_hash;
hlp = hash_table_find(&conn_hash_table, &key);
if (!hlp) {
futex_up(&async_futex);
return 0;
}
conn = hash_table_get_instance(hlp, connection_t, link);
msg->callid = callid;
msg->call = *call;
list_append(&msg->link, &conn->msg_queue);
if (IPC_GET_METHOD(*call) == IPC_M_PHONE_HUNGUP)
conn->close_callid = callid;
/* If the call is waiting for event, run it */
if (!conn->wdata.active) {
/* If in timeout list, remove it */
if (conn->wdata.inlist) {
conn->wdata.inlist = 0;
list_remove(&conn->wdata.link);
}
conn->wdata.active = 1;
psthread_add_ready(conn->wdata.ptid);
}
futex_up(&async_futex);
return 1;
}
/** Return new incoming message for current(thread-local) connection */
ipc_callid_t async_get_call_timeout(ipc_call_t *call, suseconds_t usecs)
{
msg_t *msg;
ipc_callid_t callid;
connection_t *conn;
/* GCC 4.1.0 coughs on PS_connection-> dereference,
* GCC 4.1.1 happilly puts the rdhwr instruction in delay slot.
* I would never expect to find so many errors in
* compiler *($&$(*&$
*/
conn = PS_connection;
futex_down(&async_futex);
if (usecs) {
gettimeofday(&conn->wdata.expires, NULL);
tv_add(&conn->wdata.expires, usecs);
} else {
conn->wdata.inlist = 0;
}
/* If nothing in queue, wait until something appears */
while (list_empty(&conn->msg_queue)) {
if (usecs)
insert_timeout(&conn->wdata);
conn->wdata.active = 0;
psthread_schedule_next_adv(PS_TO_MANAGER);
/* Futex is up after getting back from async_manager
* get it again */
futex_down(&async_futex);
if (usecs && conn->wdata.timedout && \
list_empty(&conn->msg_queue)) {
/* If we timed out-> exit */
futex_up(&async_futex);
return 0;
}
}
msg = list_get_instance(conn->msg_queue.next, msg_t, link);
list_remove(&msg->link);
callid = msg->callid;
*call = msg->call;
futex_up(&async_futex);
return callid;
}
/** Thread function that gets created on new connection
*
* This function is defined as a weak symbol - to be redefined in
* user code.
*/
static void default_client_connection(ipc_callid_t callid, ipc_call_t *call)
{
ipc_answer_fast(callid, ENOENT, 0, 0);
}
static void default_interrupt_received(ipc_callid_t callid, ipc_call_t *call)
{
}
/** Wrapper for client connection thread
*
* When new connection arrives, thread with this function is created.
* It calls client_connection and does final cleanup.
*
* @param arg Connection structure pointer
*/
static int connection_thread(void *arg)
{
unsigned long key;
msg_t *msg;
int close_answered = 0;
/* Setup thread local connection pointer */
PS_connection = (connection_t *)arg;
PS_connection->cthread(PS_connection->callid, &PS_connection->call);
/* Remove myself from connection hash table */
futex_down(&async_futex);
key = PS_connection->in_phone_hash;
hash_table_remove(&conn_hash_table, &key, 1);
futex_up(&async_futex);
/* Answer all remaining messages with ehangup */
while (!list_empty(&PS_connection->msg_queue)) {
msg = list_get_instance(PS_connection->msg_queue.next, msg_t, link);
list_remove(&msg->link);
if (msg->callid == PS_connection->close_callid)
close_answered = 1;
ipc_answer_fast(msg->callid, EHANGUP, 0, 0);
}
if (PS_connection->close_callid)
ipc_answer_fast(PS_connection->close_callid, 0, 0, 0);
}
/** Create new thread for a new connection
*
* Creates new thread for connection, fills in connection
* structures and inserts it into the hash table, so that
* later we can easily do routing of messages to particular
* threads.
*
* @param in_phone_hash Identification of the incoming connection
* @param callid Callid of the IPC_M_CONNECT_ME_TO packet
* @param call Call data of the opening packet
* @param cthread Thread function that should be called upon
* opening the connection
* @return New thread id
*/
pstid_t async_new_connection(ipcarg_t in_phone_hash,ipc_callid_t callid,
ipc_call_t *call,
void (*cthread)(ipc_callid_t,ipc_call_t *))
{
pstid_t ptid;
connection_t *conn;
unsigned long key;
if (!conn) {
ipc_answer_fast(callid, ENOMEM, 0, 0);
return NULL;
}
conn->in_phone_hash = in_phone_hash;
list_initialize(&conn->msg_queue);
conn->callid = callid;
conn->close_callid = 0;
if (call)
conn->call = *call;
conn->wdata.active = 1; /* We will activate it asap */
conn->cthread = cthread;
conn->wdata.ptid = psthread_create(connection_thread, conn);
if (!conn->wdata.ptid) {
ipc_answer_fast(callid, ENOMEM, 0, 0);
return NULL;
}
/* Add connection to hash table */
key = conn->in_phone_hash;
futex_down(&async_futex);
hash_table_insert(&conn_hash_table, &key, &conn->link);
futex_up(&async_futex);
psthread_add_ready(conn->wdata.ptid);
return conn->wdata.ptid;
}
/** Handle call that was received */
static void handle_call(ipc_callid_t callid, ipc_call_t *call)
{
/* Unrouted call - do some default behaviour */
if ((callid & IPC_CALLID_NOTIFICATION)) {
in_interrupt_handler = 1;
(*interrupt_received)(callid,call);
in_interrupt_handler = 0;
return;
}
switch (IPC_GET_METHOD(*call)) {
case IPC_M_CONNECT_ME_TO:
/* Open new connection with thread etc. */
async_new_connection(IPC_GET_ARG3(*call), callid, call, client_connection);
return;
}
/* Try to route call through connection tables */
if (route_call(callid, call))
return;
/* Unknown call from unknown phone - hang it up */
ipc_answer_fast(callid, EHANGUP, 0, 0);
}
/** Fire all timeouts that expired
*
*/
static void handle_expired_timeouts(void)
{
struct timeval tv;
awaiter_t *waiter;
link_t *cur;
gettimeofday(&tv,NULL);
futex_down(&async_futex);
cur = timeout_list.next;
while (cur != &timeout_list) {
waiter = list_get_instance(cur,awaiter_t,link);
if (tv_gt(&waiter->expires, &tv))
break;
cur = cur->next;
list_remove(&waiter->link);
waiter->inlist = 0;
waiter->timedout = 1;
/* Redundant condition? The thread should not
* be active when it gets here.
*/
if (!waiter->active) {
waiter->active = 1;
psthread_add_ready(waiter->ptid);
}
}
futex_up(&async_futex);
}
/** Endless loop dispatching incoming calls and answers */
static int async_manager_worker(void)
{
ipc_call_t call;
ipc_callid_t callid;
int timeout;
awaiter_t *waiter;
struct timeval tv;
while (1) {
if (psthread_schedule_next_adv(PS_FROM_MANAGER)) {
futex_up(&async_futex); /* async_futex is always held
* when entering manager thread
*/
continue;
}
futex_down(&async_futex);
if (!list_empty(&timeout_list)) {
waiter = list_get_instance(timeout_list.next,awaiter_t,link);
gettimeofday(&tv,NULL);
if (tv_gteq(&tv, &waiter->expires)) {
futex_up(&async_futex);
handle_expired_timeouts();
continue;
} else
timeout = tv_sub(&waiter->expires, &tv);
} else
timeout = SYNCH_NO_TIMEOUT;
futex_up(&async_futex);
callid = ipc_wait_cycle(&call, timeout, SYNCH_FLAGS_NONE);
if (!callid) {
handle_expired_timeouts();
continue;
}
if (callid & IPC_CALLID_ANSWERED) {
continue;
}
handle_call(callid, &call);
}
}
/** Function to start async_manager as a standalone thread
*
* When more kernel threads are used, one async manager should
* exist per thread. The particular implementation may change,
* currently one async_manager is started automatically per kernel
* thread except main thread.
*/
static int async_manager_thread(void *arg)
{
futex_up(&async_futex); /* async_futex is always locked when entering
* manager */
async_manager_worker();
}
/** Add one manager to manager list */
void async_create_manager(void)
{
pstid_t ptid;
ptid = psthread_create(async_manager_thread, NULL);
psthread_add_manager(ptid);
}
/** Remove one manager from manager list */
void async_destroy_manager(void)
{
psthread_remove_manager();
}
/** Initialize internal structures needed for async manager */
int _async_init(void)
{
if (!hash_table_create(&conn_hash_table, CONN_HASH_TABLE_CHAINS, 1, &conn_hash_table_ops)) {
printf("%s: cannot create hash table\n", "async"); return ENOMEM;
}
}
/** IPC handler for messages in async framework
*
* Notify thread that is waiting for this message, that it arrived
*/
static void reply_received(void *private, int retval,
ipc_call_t *data)
{
amsg_t *msg = (amsg_t *) private;
msg->retval = retval;
futex_down(&async_futex);
/* Copy data after futex_down, just in case the
* call was detached
*/
if (msg->dataptr)
*msg->dataptr = *data;
write_barrier();
/* Remove message from timeout list */
if (msg->wdata.inlist)
list_remove(&msg->wdata.link);
msg->done = 1;
if (! msg->wdata.active) {
msg->wdata.active = 1;
psthread_add_ready(msg->wdata.ptid);
}
futex_up(&async_futex);
}
/** Send message and return id of the sent message
*
* The return value can be used as input for async_wait() to wait
* for completion.
*/
aid_t async_send_2(int phoneid, ipcarg_t method, ipcarg_t arg1, ipcarg_t arg2,
ipc_call_t *dataptr)
{
amsg_t *msg;
if (in_interrupt_handler) {
printf("Cannot send asynchronou request in interrupt handler.\n"); _exit(1);
}
msg->done = 0;
msg->dataptr = dataptr;
msg->wdata.active = 1; /* We may sleep in next method, but it
* will use it's own mechanism */
ipc_call_async_2(phoneid,method,arg1,arg2,msg,reply_received,1);
return (aid_t) msg;
}
/** Send message and return id of the sent message
*
* The return value can be used as input for async_wait() to wait
* for completion.
*/
aid_t async_send_3(int phoneid, ipcarg_t method, ipcarg_t arg1, ipcarg_t arg2,
ipcarg_t arg3, ipc_call_t *dataptr)
{
amsg_t *msg;
if (in_interrupt_handler) {
printf("Cannot send asynchronou request in interrupt handler.\n"); _exit(1);
}
msg->done = 0;
msg->dataptr = dataptr;
msg->wdata.active = 1; /* We may sleep in next method, but it
* will use it's own mechanism */
ipc_call_async_3(phoneid,method,arg1,arg2,arg3, msg,reply_received,1);
return (aid_t) msg;
}
/** Wait for a message sent by async framework
*
* @param amsgid Message ID to wait for
* @param retval Pointer to variable where will be stored retval
* of the answered message. If NULL, it is ignored.
*
*/
void async_wait_for(aid_t amsgid, ipcarg_t *retval)
{
amsg_t *msg = (amsg_t *) amsgid;
connection_t *conn;
futex_down(&async_futex);
if (msg->done) {
futex_up(&async_futex);
goto done;
}
msg->wdata.ptid = psthread_get_id();
msg->wdata.active = 0;
msg->wdata.inlist = 0;
/* Leave locked async_futex when entering this function */
psthread_schedule_next_adv(PS_TO_MANAGER);
/* futex is up automatically after psthread_schedule_next...*/
done:
if (retval)
*retval = msg->retval;
}
/** Wait for a message sent by async framework with timeout
*
* @param amsgid Message ID to wait for
* @param retval Pointer to variable where will be stored retval
* of the answered message. If NULL, it is ignored.
* @param timeout Timeout in usecs
* @return 0 on success, ETIMEOUT if timeout expired
*
*/
int async_wait_timeout(aid_t amsgid, ipcarg_t *retval, suseconds_t timeout)
{
amsg_t *msg = (amsg_t *) amsgid;
connection_t *conn;
/* TODO: Let it go through the event read at least once */
if (timeout < 0)
return ETIMEOUT;
futex_down(&async_futex);
if (msg->done) {
futex_up(&async_futex);
goto done;
}
gettimeofday(&msg->wdata.expires, NULL);
tv_add(&msg->wdata.expires, timeout);
msg->wdata.ptid = psthread_get_id();
msg->wdata.active = 0;
insert_timeout(&msg->wdata);
/* Leave locked async_futex when entering this function */
psthread_schedule_next_adv(PS_TO_MANAGER);
/* futex is up automatically after psthread_schedule_next...*/
if (!msg->done)
return ETIMEOUT;
done:
if (retval)
*retval = msg->retval;
return 0;
}
/** Wait specified time, but in the meantime handle incoming events
*
* @param timeout Time in microseconds to wait
*/
void async_usleep(suseconds_t timeout)
{
amsg_t *msg;
if (in_interrupt_handler) {
printf("Cannot call async_usleep in interrupt handler.\n"); _exit(1);
}
if (!msg)
return;
msg->wdata.ptid = psthread_get_id();
msg->wdata.active = 0;
gettimeofday(&msg->wdata.expires, NULL);
tv_add(&msg->wdata.expires, timeout);
futex_down(&async_futex);
insert_timeout(&msg->wdata);
/* Leave locked async_futex when entering this function */
psthread_schedule_next_adv(PS_TO_MANAGER);
/* futex is up automatically after psthread_schedule_next...*/
}
/** Set function that is called, IPC_M_CONNECT_ME_TO is received
*
* @param conn Function that will form new psthread.
*/
void async_set_client_connection(async_client_conn_t conn)
{
client_connection = conn;
}
void async_set_interrupt_received(async_client_conn_t conn)
{
interrupt_received = conn;
}
/* Primitive functions for simple communication */
void async_msg_3(int phoneid, ipcarg_t method, ipcarg_t arg1,
ipcarg_t arg2, ipcarg_t arg3)
{
ipc_call_async_3(phoneid, method, arg1, arg2, arg3, NULL, NULL, !in_interrupt_handler);
}
void async_msg_2(int phoneid, ipcarg_t method, ipcarg_t arg1, ipcarg_t arg2)
{
ipc_call_async_2(phoneid, method, arg1, arg2, NULL, NULL, !in_interrupt_handler);
}
/** @}
*/