haproxy/include/proto/applet.h
Willy Tarreau 21028b5e7f MEDIUM: appctx: check for allocation attempts in buffer allocation callbacks
The buffer allocation callback appctx_res_wakeup() used to rely on old
tricks to detect if a buffer was already granted to an appctx, namely
by checking the task's state. Not only this test is not valid anymore,
but it's inaccurate.

Let's solely on SI_FL_WAIT_ROOM that is now set on allocation failure by
the functions trying to allocate a buffer. The buffer is now allocated on
the fly and the flag removed so that the consistency between the two
remains granted. The patch also fixes minor issues such as the function
being improperly declared inline(!) and the fact that using appctx_wakeup()
sets the wakeup reason to TASK_WOKEN_OTHER while we try to use TASK_WOKEN_RES
when waking up consecutive to a ressource allocation such as a buffer.
2018-11-11 10:18:37 +01:00

131 lines
3.8 KiB
C

/*
* include/proto/applet.h
* This file contains applet function prototypes
*
* Copyright (C) 2000-2015 Willy Tarreau - w@1wt.eu
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, version 2.1
* exclusively.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _PROTO_APPLET_H
#define _PROTO_APPLET_H
#include <stdlib.h>
#include <common/config.h>
#include <common/mini-clist.h>
#include <types/applet.h>
#include <proto/connection.h>
#include <proto/task.h>
extern unsigned int nb_applets;
struct task *task_run_applet(struct task *t, void *context, unsigned short state);
int appctx_buf_available(void *arg);
/* Initializes all required fields for a new appctx. Note that it does the
* minimum acceptable initialization for an appctx. This means only the
* 3 integer states st0, st1, st2 and the chunk used to gather unfinished
* commands are zeroed
*/
static inline void appctx_init(struct appctx *appctx, unsigned long thread_mask)
{
appctx->st0 = appctx->st1 = appctx->st2 = 0;
appctx->chunk = NULL;
appctx->io_release = NULL;
appctx->thread_mask = thread_mask;
appctx->state = 0;
}
/* Tries to allocate a new appctx and initialize its main fields. The appctx
* is returned on success, NULL on failure. The appctx must be released using
* pool_free(connection) or appctx_free(), since it's allocated from the
* connection pool. <applet> is assigned as the applet, but it can be NULL.
*/
static inline struct appctx *appctx_new(struct applet *applet, unsigned long thread_mask)
{
struct appctx *appctx;
appctx = pool_alloc(pool_head_connection);
if (likely(appctx != NULL)) {
appctx->obj_type = OBJ_TYPE_APPCTX;
appctx->applet = applet;
appctx_init(appctx, thread_mask);
appctx->t = task_new(thread_mask);
if (unlikely(appctx->t == NULL)) {
pool_free(pool_head_connection, appctx);
return NULL;
}
appctx->t->process = task_run_applet;
appctx->t->context = appctx;
LIST_INIT(&appctx->buffer_wait.list);
appctx->buffer_wait.target = appctx;
appctx->buffer_wait.wakeup_cb = appctx_buf_available;
HA_ATOMIC_ADD(&nb_applets, 1);
}
return appctx;
}
/* Releases an appctx previously allocated by appctx_new(). Note that
* we share the connection pool.
*/
static inline void __appctx_free(struct appctx *appctx)
{
task_delete(appctx->t);
task_free(appctx->t);
if (!LIST_ISEMPTY(&appctx->buffer_wait.list)) {
HA_SPIN_LOCK(BUF_WQ_LOCK, &buffer_wq_lock);
LIST_DEL(&appctx->buffer_wait.list);
LIST_INIT(&appctx->buffer_wait.list);
HA_SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock);
}
pool_free(pool_head_connection, appctx);
HA_ATOMIC_SUB(&nb_applets, 1);
}
static inline void appctx_free(struct appctx *appctx)
{
/* The task is supposed to be run on this thread, so we can just
* check if it's running already (or about to run) or not
*/
if (!(appctx->t->state & TASK_RUNNING))
__appctx_free(appctx);
else {
/* if it's running, or about to run, defer the freeing
* until the callback is called.
*/
appctx->state |= APPLET_WANT_DIE;
task_wakeup(appctx->t, TASK_WOKEN_OTHER);
}
}
/* wakes up an applet when conditions have changed */
static inline void appctx_wakeup(struct appctx *appctx)
{
task_wakeup(appctx->t, TASK_WOKEN_OTHER);
}
#endif /* _PROTO_APPLET_H */
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/