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samba-mirror/lib/tevent/tevent_threads.c
Michael Adam 149fa72770 tevent:threads: fix -O3 error unused result of write
some compilers don't tolerate void-casting for warn_unused_result

Signed-off-by: Michael Adam <obnox@samba.org>
Reviewed-by: Christian Ambach <ambi@samba.org>
2016-05-13 00:16:14 +02:00

374 lines
8.1 KiB
C

/*
tevent event library.
Copyright (C) Jeremy Allison 2015
** NOTE! The following LGPL license applies to the tevent
** library. This does NOT imply that all of Samba is released
** under the LGPL
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; either
version 3 of the License, or (at your option) any later version.
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, see <http://www.gnu.org/licenses/>.
*/
#include "replace.h"
#include "system/filesys.h"
#include "talloc.h"
#include "tevent.h"
#include "tevent_internal.h"
#include "tevent_util.h"
#if defined(HAVE_PTHREAD)
#include <pthread.h>
struct tevent_immediate_list {
struct tevent_immediate_list *next, *prev;
tevent_immediate_handler_t handler;
struct tevent_immediate *im;
void *private_ptr;
};
struct tevent_thread_proxy {
pthread_mutex_t mutex;
struct tevent_context *dest_ev_ctx;
int read_fd;
int write_fd;
struct tevent_fd *pipe_read_fde;
/* Pending events list. */
struct tevent_immediate_list *im_list;
/* Completed events list. */
struct tevent_immediate_list *tofree_im_list;
struct tevent_immediate *free_im;
};
static void free_im_list(struct tevent_immediate_list **pp_list_head)
{
struct tevent_immediate_list *im_entry = NULL;
struct tevent_immediate_list *im_next = NULL;
for (im_entry = *pp_list_head; im_entry; im_entry = im_next) {
im_next = im_entry->next;
DLIST_REMOVE(*pp_list_head, im_entry);
TALLOC_FREE(im_entry);
}
}
static void free_list_handler(struct tevent_context *ev,
struct tevent_immediate *im,
void *private_ptr)
{
struct tevent_thread_proxy *tp =
talloc_get_type_abort(private_ptr, struct tevent_thread_proxy);
int ret;
ret = pthread_mutex_lock(&tp->mutex);
if (ret != 0) {
abort();
/* Notreached. */
return;
}
free_im_list(&tp->tofree_im_list);
ret = pthread_mutex_unlock(&tp->mutex);
if (ret != 0) {
abort();
/* Notreached. */
return;
}
}
static void schedule_immediate_functions(struct tevent_thread_proxy *tp)
{
struct tevent_immediate_list *im_entry = NULL;
struct tevent_immediate_list *im_next = NULL;
for (im_entry = tp->im_list; im_entry; im_entry = im_next) {
im_next = im_entry->next;
DLIST_REMOVE(tp->im_list, im_entry);
tevent_schedule_immediate(im_entry->im,
tp->dest_ev_ctx,
im_entry->handler,
im_entry->private_ptr);
/* Move from pending list to free list. */
DLIST_ADD(tp->tofree_im_list, im_entry);
}
if (tp->tofree_im_list != NULL) {
/*
* Once the current immediate events
* are processed, we need to reshedule
* ourselves to free them. This works
* as tevent_schedule_immediate()
* always adds events to the *END* of
* the immediate events list.
*/
tevent_schedule_immediate(tp->free_im,
tp->dest_ev_ctx,
free_list_handler,
tp);
}
}
static void pipe_read_handler(struct tevent_context *ev,
struct tevent_fd *fde,
uint16_t flags,
void *private_ptr)
{
struct tevent_thread_proxy *tp =
talloc_get_type_abort(private_ptr, struct tevent_thread_proxy);
ssize_t len = 64;
int ret;
ret = pthread_mutex_lock(&tp->mutex);
if (ret != 0) {
abort();
/* Notreached. */
return;
}
/*
* Clear out all data in the pipe. We
* don't really care if this returns -1.
*/
while (len == 64) {
char buf[64];
len = read(tp->read_fd, buf, 64);
};
schedule_immediate_functions(tp);
ret = pthread_mutex_unlock(&tp->mutex);
if (ret != 0) {
abort();
/* Notreached. */
return;
}
}
static int tevent_thread_proxy_destructor(struct tevent_thread_proxy *tp)
{
int ret;
ret = pthread_mutex_lock(&tp->mutex);
if (ret != 0) {
abort();
/* Notreached. */
return 0;
}
TALLOC_FREE(tp->pipe_read_fde);
if (tp->read_fd != -1) {
(void)close(tp->read_fd);
tp->read_fd = -1;
}
if (tp->write_fd != -1) {
(void)close(tp->write_fd);
tp->write_fd = -1;
}
/* Hmmm. It's probably an error if we get here with
any non-NULL immediate entries.. */
free_im_list(&tp->im_list);
free_im_list(&tp->tofree_im_list);
TALLOC_FREE(tp->free_im);
ret = pthread_mutex_unlock(&tp->mutex);
if (ret != 0) {
abort();
/* Notreached. */
return 0;
}
ret = pthread_mutex_destroy(&tp->mutex);
if (ret != 0) {
abort();
/* Notreached. */
return 0;
}
return 0;
}
/*
* Create a struct that can be passed to other threads
* to allow them to signal the struct tevent_context *
* passed in.
*/
struct tevent_thread_proxy *tevent_thread_proxy_create(
struct tevent_context *dest_ev_ctx)
{
int ret;
int pipefds[2];
struct tevent_thread_proxy *tp;
tp = talloc_zero(dest_ev_ctx, struct tevent_thread_proxy);
if (tp == NULL) {
return NULL;
}
ret = pthread_mutex_init(&tp->mutex, NULL);
if (ret != 0) {
goto fail;
}
tp->dest_ev_ctx = dest_ev_ctx;
tp->read_fd = -1;
tp->write_fd = -1;
talloc_set_destructor(tp, tevent_thread_proxy_destructor);
ret = pipe(pipefds);
if (ret == -1) {
goto fail;
}
tp->read_fd = pipefds[0];
tp->write_fd = pipefds[1];
ret = ev_set_blocking(pipefds[0], false);
if (ret != 0) {
goto fail;
}
ret = ev_set_blocking(pipefds[1], false);
if (ret != 0) {
goto fail;
}
if (!ev_set_close_on_exec(pipefds[0])) {
goto fail;
}
if (!ev_set_close_on_exec(pipefds[1])) {
goto fail;
}
tp->pipe_read_fde = tevent_add_fd(dest_ev_ctx,
tp,
tp->read_fd,
TEVENT_FD_READ,
pipe_read_handler,
tp);
if (tp->pipe_read_fde == NULL) {
goto fail;
}
/*
* Create an immediate event to free
* completed lists.
*/
tp->free_im = tevent_create_immediate(tp);
if (tp->free_im == NULL) {
goto fail;
}
return tp;
fail:
TALLOC_FREE(tp);
return NULL;
}
/*
* This function schedules an immediate event to be called with argument
* *pp_private in the thread context of dest_ev_ctx. Caller doesn't
* wait for activation to take place, this is simply fire-and-forget.
*
* pp_im must be a pointer to an immediate event talloced on
* a context owned by the calling thread, or the NULL context.
* Ownership of *pp_im will be transfered to the tevent library.
*
* pp_private can be null, or contents of *pp_private must be
* talloc'ed memory on a context owned by the calling thread
* or the NULL context. If non-null, ownership of *pp_private will
* be transfered to the tevent library.
*
* If you want to return a message, have the destination use the
* same function call to send back to the caller.
*/
void tevent_thread_proxy_schedule(struct tevent_thread_proxy *tp,
struct tevent_immediate **pp_im,
tevent_immediate_handler_t handler,
void *pp_private_data)
{
struct tevent_immediate_list *im_entry;
int ret;
char c;
ssize_t written;
ret = pthread_mutex_lock(&tp->mutex);
if (ret != 0) {
abort();
/* Notreached. */
return;
}
if (tp->write_fd == -1) {
/* In the process of being destroyed. Ignore. */
goto end;
}
/* Create a new immediate_list entry. MUST BE ON THE NULL CONTEXT */
im_entry = talloc_zero(NULL, struct tevent_immediate_list);
if (im_entry == NULL) {
goto end;
}
im_entry->handler = handler;
im_entry->im = talloc_move(im_entry, pp_im);
if (pp_private_data != NULL) {
void **pptr = (void **)pp_private_data;
im_entry->private_ptr = talloc_move(im_entry, pptr);
}
DLIST_ADD(tp->im_list, im_entry);
/* And notify the dest_ev_ctx to wake up. */
c = '\0';
do {
written = write(tp->write_fd, &c, 1);
} while (written == -1 && errno == EINTR);
end:
ret = pthread_mutex_unlock(&tp->mutex);
if (ret != 0) {
abort();
/* Notreached. */
}
}
#else
/* !HAVE_PTHREAD */
struct tevent_thread_proxy *tevent_thread_proxy_create(
struct tevent_context *dest_ev_ctx)
{
errno = ENOSYS;
return NULL;
}
void tevent_thread_proxy_schedule(struct tevent_thread_proxy *tp,
struct tevent_immediate **pp_im,
tevent_immediate_handler_t handler,
void *pp_private_data)
{
;
}
#endif