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samba-mirror/lib/pthreadpool/pthreadpool_tevent.c
Stefan Metzmacher 25756425aa pthreadpool: maintain a global list of orphaned pthreadpool_tevent_jobs
Instead of leaking the memory forever, we retry the cleanup,
if other pthreadpool_tevent_*() functions are used.

pthreadpool_tevent_cleanup_orphaned_jobs() could also be called
by external callers.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
2018-07-12 14:25:19 +02:00

615 lines
15 KiB
C

/*
* Unix SMB/CIFS implementation.
* threadpool implementation based on pthreads
* Copyright (C) Volker Lendecke 2009,2011
*
* 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/>.
*/
#include "replace.h"
#include "pthreadpool_tevent.h"
#include "pthreadpool.h"
#include "lib/util/tevent_unix.h"
#include "lib/util/dlinklist.h"
struct pthreadpool_tevent_job_state;
/*
* We need one pthreadpool_tevent_glue object per unique combintaion of tevent
* contexts and pthreadpool_tevent objects. Maintain a list of used tevent
* contexts in a pthreadpool_tevent.
*/
struct pthreadpool_tevent_glue {
struct pthreadpool_tevent_glue *prev, *next;
struct pthreadpool_tevent *pool; /* back-pointer to owning object. */
/* Tuple we are keeping track of in this list. */
struct tevent_context *ev;
struct tevent_threaded_context *tctx;
/* Pointer to link object owned by *ev. */
struct pthreadpool_tevent_glue_ev_link *ev_link;
};
/*
* The pthreadpool_tevent_glue_ev_link and its destructor ensure we remove the
* tevent context from our list of active event contexts if the event context
* is destroyed.
* This structure is talloc()'ed from the struct tevent_context *, and is a
* back-pointer allowing the related struct pthreadpool_tevent_glue object
* to be removed from the struct pthreadpool_tevent glue list if the owning
* tevent_context is talloc_free()'ed.
*/
struct pthreadpool_tevent_glue_ev_link {
struct pthreadpool_tevent_glue *glue;
};
struct pthreadpool_tevent {
struct pthreadpool *pool;
struct pthreadpool_tevent_glue *glue_list;
struct pthreadpool_tevent_job *jobs;
};
struct pthreadpool_tevent_job_state {
struct tevent_context *ev;
struct tevent_req *req;
struct pthreadpool_tevent_job *job;
};
struct pthreadpool_tevent_job {
struct pthreadpool_tevent_job *prev, *next;
struct pthreadpool_tevent *pool;
struct pthreadpool_tevent_job_state *state;
struct tevent_immediate *im;
void (*fn)(void *private_data);
void *private_data;
};
static int pthreadpool_tevent_destructor(struct pthreadpool_tevent *pool);
static void pthreadpool_tevent_job_orphan(struct pthreadpool_tevent_job *job);
static struct pthreadpool_tevent_job *orphaned_jobs;
void pthreadpool_tevent_cleanup_orphaned_jobs(void)
{
struct pthreadpool_tevent_job *job = NULL;
struct pthreadpool_tevent_job *njob = NULL;
for (job = orphaned_jobs; job != NULL; job = njob) {
njob = job->next;
/*
* The job destructor keeps the job alive
* (and in the list) or removes it from the list.
*/
TALLOC_FREE(job);
}
}
static int pthreadpool_tevent_job_signal(int jobid,
void (*job_fn)(void *private_data),
void *job_private_data,
void *private_data);
int pthreadpool_tevent_init(TALLOC_CTX *mem_ctx, unsigned max_threads,
struct pthreadpool_tevent **presult)
{
struct pthreadpool_tevent *pool;
int ret;
pthreadpool_tevent_cleanup_orphaned_jobs();
pool = talloc_zero(mem_ctx, struct pthreadpool_tevent);
if (pool == NULL) {
return ENOMEM;
}
ret = pthreadpool_init(max_threads, &pool->pool,
pthreadpool_tevent_job_signal, pool);
if (ret != 0) {
TALLOC_FREE(pool);
return ret;
}
talloc_set_destructor(pool, pthreadpool_tevent_destructor);
*presult = pool;
return 0;
}
size_t pthreadpool_tevent_max_threads(struct pthreadpool_tevent *pool)
{
if (pool->pool == NULL) {
return 0;
}
return pthreadpool_max_threads(pool->pool);
}
size_t pthreadpool_tevent_queued_jobs(struct pthreadpool_tevent *pool)
{
if (pool->pool == NULL) {
return 0;
}
return pthreadpool_queued_jobs(pool->pool);
}
static int pthreadpool_tevent_destructor(struct pthreadpool_tevent *pool)
{
struct pthreadpool_tevent_job *job = NULL;
struct pthreadpool_tevent_job *njob = NULL;
struct pthreadpool_tevent_glue *glue = NULL;
int ret;
ret = pthreadpool_stop(pool->pool);
if (ret != 0) {
return ret;
}
for (job = pool->jobs; job != NULL; job = njob) {
njob = job->next;
/* The job this removes it from the list */
pthreadpool_tevent_job_orphan(job);
}
/*
* Delete all the registered
* tevent_context/tevent_threaded_context
* pairs.
*/
for (glue = pool->glue_list; glue != NULL; glue = pool->glue_list) {
/* The glue destructor removes it from the list */
TALLOC_FREE(glue);
}
pool->glue_list = NULL;
ret = pthreadpool_destroy(pool->pool);
if (ret != 0) {
return ret;
}
pool->pool = NULL;
pthreadpool_tevent_cleanup_orphaned_jobs();
return 0;
}
static int pthreadpool_tevent_glue_destructor(
struct pthreadpool_tevent_glue *glue)
{
if (glue->pool->glue_list != NULL) {
DLIST_REMOVE(glue->pool->glue_list, glue);
}
/* Ensure the ev_link destructor knows we're gone */
glue->ev_link->glue = NULL;
TALLOC_FREE(glue->ev_link);
TALLOC_FREE(glue->tctx);
return 0;
}
/*
* Destructor called either explicitly from
* pthreadpool_tevent_glue_destructor(), or indirectly
* when owning tevent_context is destroyed.
*
* When called from pthreadpool_tevent_glue_destructor()
* ev_link->glue is already NULL, so this does nothing.
*
* When called from talloc_free() of the owning
* tevent_context we must ensure we also remove the
* linked glue object from the list inside
* struct pthreadpool_tevent.
*/
static int pthreadpool_tevent_glue_link_destructor(
struct pthreadpool_tevent_glue_ev_link *ev_link)
{
TALLOC_FREE(ev_link->glue);
return 0;
}
static int pthreadpool_tevent_register_ev(struct pthreadpool_tevent *pool,
struct tevent_context *ev)
{
struct pthreadpool_tevent_glue *glue = NULL;
struct pthreadpool_tevent_glue_ev_link *ev_link = NULL;
/*
* See if this tevent_context was already registered by
* searching the glue object list. If so we have nothing
* to do here - we already have a tevent_context/tevent_threaded_context
* pair.
*/
for (glue = pool->glue_list; glue != NULL; glue = glue->next) {
if (glue->ev == ev) {
return 0;
}
}
/*
* Event context not yet registered - create a new glue
* object containing a tevent_context/tevent_threaded_context
* pair and put it on the list to remember this registration.
* We also need a link object to ensure the event context
* can't go away without us knowing about it.
*/
glue = talloc_zero(pool, struct pthreadpool_tevent_glue);
if (glue == NULL) {
return ENOMEM;
}
*glue = (struct pthreadpool_tevent_glue) {
.pool = pool,
.ev = ev,
};
talloc_set_destructor(glue, pthreadpool_tevent_glue_destructor);
/*
* Now allocate the link object to the event context. Note this
* is allocated OFF THE EVENT CONTEXT ITSELF, so if the event
* context is freed we are able to cleanup the glue object
* in the link object destructor.
*/
ev_link = talloc_zero(ev, struct pthreadpool_tevent_glue_ev_link);
if (ev_link == NULL) {
TALLOC_FREE(glue);
return ENOMEM;
}
ev_link->glue = glue;
talloc_set_destructor(ev_link, pthreadpool_tevent_glue_link_destructor);
glue->ev_link = ev_link;
#ifdef HAVE_PTHREAD
glue->tctx = tevent_threaded_context_create(pool, ev);
if (glue->tctx == NULL) {
TALLOC_FREE(ev_link);
TALLOC_FREE(glue);
return ENOMEM;
}
#endif
DLIST_ADD(pool->glue_list, glue);
return 0;
}
static void pthreadpool_tevent_job_fn(void *private_data);
static void pthreadpool_tevent_job_done(struct tevent_context *ctx,
struct tevent_immediate *im,
void *private_data);
static bool pthreadpool_tevent_job_cancel(struct tevent_req *req);
static int pthreadpool_tevent_job_destructor(struct pthreadpool_tevent_job *job)
{
/*
* We should never be called with state->state != NULL.
* Only pthreadpool_tevent_job_orphan() will call TALLOC_FREE(job)
* after detaching from the request state and pool list.
*/
if (job->state != NULL) {
abort();
}
/*
* If the job is not finished (job->im still there)
* and it's still attached to the pool,
* we try to cancel it (before it was starts)
*/
if (job->im != NULL && job->pool != NULL) {
size_t num;
num = pthreadpool_cancel_job(job->pool->pool, 0,
pthreadpool_tevent_job_fn,
job);
if (num != 0) {
/*
* It was not too late to cancel the request.
*
* We can remove job->im, as it will never be used.
*/
TALLOC_FREE(job->im);
}
}
/*
* pthreadpool_tevent_job_orphan() already removed
* it from pool->jobs. And we don't need try
* pthreadpool_cancel_job() again.
*/
job->pool = NULL;
if (job->im != NULL) {
/*
* state->im still there means, we need to wait for the
* immediate event to be triggered or just leak the memory.
*
* Move it to the orphaned list, if it's not already there.
*/
return -1;
}
/*
* Finally remove from the orphaned_jobs list
* and let talloc destroy us.
*/
DLIST_REMOVE(orphaned_jobs, job);
return 0;
}
static void pthreadpool_tevent_job_orphan(struct pthreadpool_tevent_job *job)
{
/*
* We're the only function that sets
* job->state = NULL;
*/
if (job->state == NULL) {
abort();
}
/*
* We need to reparent to a long term context.
* And detach from the request state.
* Maybe the destructor will keep the memory
* and leak it for now.
*/
(void)talloc_reparent(job->state, NULL, job);
job->state->job = NULL;
job->state = NULL;
/*
* job->pool will only be set to NULL
* in the first destructur run.
*/
if (job->pool == NULL) {
abort();
}
/*
* Dettach it from the pool.
*
* The job might still be running,
* so we keep job->pool.
* The destructor will set it to NULL
* after trying pthreadpool_cancel_job()
*/
DLIST_REMOVE(job->pool->jobs, job);
/*
* Add it to the list of orphaned jobs,
* which may be cleaned up later.
*
* The destructor removes it from the list
* when possible or it denies the free
* and keep it in the list.
*/
DLIST_ADD_END(orphaned_jobs, job);
TALLOC_FREE(job);
}
static void pthreadpool_tevent_job_cleanup(struct tevent_req *req,
enum tevent_req_state req_state)
{
struct pthreadpool_tevent_job_state *state =
tevent_req_data(req,
struct pthreadpool_tevent_job_state);
if (state->job == NULL) {
/*
* The job request is not scheduled in the pool
* yet or anymore.
*/
return;
}
/*
* We need to reparent to a long term context.
* Maybe the destructor will keep the memory
* and leak it for now.
*/
pthreadpool_tevent_job_orphan(state->job);
state->job = NULL; /* not needed but looks better */
return;
}
struct tevent_req *pthreadpool_tevent_job_send(
TALLOC_CTX *mem_ctx, struct tevent_context *ev,
struct pthreadpool_tevent *pool,
void (*fn)(void *private_data), void *private_data)
{
struct tevent_req *req = NULL;
struct pthreadpool_tevent_job_state *state = NULL;
struct pthreadpool_tevent_job *job = NULL;
int ret;
pthreadpool_tevent_cleanup_orphaned_jobs();
req = tevent_req_create(mem_ctx, &state,
struct pthreadpool_tevent_job_state);
if (req == NULL) {
return NULL;
}
state->ev = ev;
state->req = req;
tevent_req_set_cleanup_fn(req, pthreadpool_tevent_job_cleanup);
if (pool == NULL) {
tevent_req_error(req, EINVAL);
return tevent_req_post(req, ev);
}
if (pool->pool == NULL) {
tevent_req_error(req, EINVAL);
return tevent_req_post(req, ev);
}
ret = pthreadpool_tevent_register_ev(pool, ev);
if (tevent_req_error(req, ret)) {
return tevent_req_post(req, ev);
}
job = talloc_zero(state, struct pthreadpool_tevent_job);
if (tevent_req_nomem(job, req)) {
return tevent_req_post(req, ev);
}
job->pool = pool;
job->fn = fn;
job->private_data = private_data;
job->im = tevent_create_immediate(state->job);
if (tevent_req_nomem(job->im, req)) {
return tevent_req_post(req, ev);
}
talloc_set_destructor(job, pthreadpool_tevent_job_destructor);
DLIST_ADD_END(job->pool->jobs, job);
job->state = state;
state->job = job;
ret = pthreadpool_add_job(job->pool->pool, 0,
pthreadpool_tevent_job_fn,
job);
if (tevent_req_error(req, ret)) {
return tevent_req_post(req, ev);
}
tevent_req_set_cancel_fn(req, pthreadpool_tevent_job_cancel);
return req;
}
static void pthreadpool_tevent_job_fn(void *private_data)
{
struct pthreadpool_tevent_job *job =
talloc_get_type_abort(private_data,
struct pthreadpool_tevent_job);
job->fn(job->private_data);
}
static int pthreadpool_tevent_job_signal(int jobid,
void (*job_fn)(void *private_data),
void *job_private_data,
void *private_data)
{
struct pthreadpool_tevent_job *job =
talloc_get_type_abort(job_private_data,
struct pthreadpool_tevent_job);
struct pthreadpool_tevent_job_state *state = job->state;
struct tevent_threaded_context *tctx = NULL;
struct pthreadpool_tevent_glue *g = NULL;
if (state == NULL) {
/* Request already gone */
return 0;
}
#ifdef HAVE_PTHREAD
for (g = job->pool->glue_list; g != NULL; g = g->next) {
if (g->ev == state->ev) {
tctx = g->tctx;
break;
}
}
if (tctx == NULL) {
abort();
}
#endif
if (tctx != NULL) {
/* with HAVE_PTHREAD */
tevent_threaded_schedule_immediate(tctx, job->im,
pthreadpool_tevent_job_done,
job);
} else {
/* without HAVE_PTHREAD */
tevent_schedule_immediate(job->im, state->ev,
pthreadpool_tevent_job_done,
job);
}
return 0;
}
static void pthreadpool_tevent_job_done(struct tevent_context *ctx,
struct tevent_immediate *im,
void *private_data)
{
struct pthreadpool_tevent_job *job =
talloc_get_type_abort(private_data,
struct pthreadpool_tevent_job);
struct pthreadpool_tevent_job_state *state = job->state;
TALLOC_FREE(job->im);
if (state == NULL) {
/* Request already gone */
TALLOC_FREE(job);
return;
}
/*
* pthreadpool_tevent_job_cleanup()
* will destroy the job.
*/
tevent_req_done(state->req);
}
static bool pthreadpool_tevent_job_cancel(struct tevent_req *req)
{
struct pthreadpool_tevent_job_state *state =
tevent_req_data(req,
struct pthreadpool_tevent_job_state);
struct pthreadpool_tevent_job *job = state->job;
size_t num;
if (job == NULL) {
return false;
}
num = pthreadpool_cancel_job(job->pool->pool, 0,
pthreadpool_tevent_job_fn,
job);
if (num == 0) {
/*
* It was too late to cancel the request.
*/
return false;
}
/*
* It was not too late to cancel the request.
*
* We can remove job->im, as it will never be used.
*/
TALLOC_FREE(job->im);
/*
* pthreadpool_tevent_job_cleanup()
* will destroy the job.
*/
tevent_req_defer_callback(req, state->ev);
tevent_req_error(req, ECANCELED);
return true;
}
int pthreadpool_tevent_job_recv(struct tevent_req *req)
{
return tevent_req_simple_recv_unix(req);
}