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r22830: merged the latest lib/events updates from ctdb to Samba4. This

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includes a new EVENT_FD_AUTOCLOSE flag that prevents race conditions
where code using fd events might close a fd before releasing the
struct fd_event. That causes headaches for epoll.
This commit is contained in:
Andrew Tridgell 2007-05-14 00:57:48 +00:00 committed by Gerald (Jerry) Carter
parent 2c9d0b57f9
commit f1ad216de1
9 changed files with 74 additions and 8 deletions
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1
source/lib/events/config.m4
View File

@ -5,6 +5,7 @@ AC_CHECK_HEADERS(sys/epoll.h)
AC_CHECK_FUNCS(epoll_create)
if test x"$ac_cv_header_sys_epoll_h" = x"yes" -a x"$ac_cv_func_epoll_create" = x"yes";then
SMB_ENABLE(EVENTS_EPOLL,YES)
AC_DEFINE(HAVE_EVENTS_EPOLL, 1, [Whether epoll is available])
# check for native Linux AIO interface
AC_CHECK_HEADERS(libaio.h)

25
source/lib/events/events.c
View File

@ -71,6 +71,8 @@ struct event_ops_list {
/* list of registered event backends */
static struct event_ops_list *event_backends;
static char *event_default_backend = NULL;
/*
register an events backend
*/
@ -85,6 +87,15 @@ bool event_register_backend(const char *name, const struct event_ops *ops)
return True;
}
/*
set the default event backend
*/
void event_set_default_backend(const char *backend)
{
if (event_default_backend) free(event_default_backend);
event_default_backend = strdup(backend);
}
/*
initialise backends if not already done
*/
@ -99,7 +110,15 @@ static void event_backend_init(void)
run_init_functions(shared_init);
#else
bool events_standard_init(void);
bool events_select_init(void);
events_select_init();
events_standard_init();
#if HAVE_EVENTS_EPOLL
{
bool events_epoll_init(void);
events_epoll_init();
}
#endif
#endif
}
@ -169,6 +188,9 @@ struct event_context *event_context_init_byname(TALLOC_CTX *mem_ctx, const char
name = lp_parm_string(-1, "event", "backend");
}
#endif
if (name == NULL) {
name = event_default_backend;
}
if (name == NULL) {
name = "standard";
}
@ -195,6 +217,9 @@ struct event_context *event_context_init(TALLOC_CTX *mem_ctx)
/*
add a fd based event
return NULL on failure (memory allocation error)
if flags contains EVENT_FD_AUTOCLOSE then the fd will be closed when
the returned fd_event context is freed
*/
struct fd_event *event_add_fd(struct event_context *ev, TALLOC_CTX *mem_ctx,
int fd, uint16_t flags, event_fd_handler_t handler,

2
source/lib/events/events.h
View File

@ -46,6 +46,7 @@ typedef void (*event_aio_handler_t)(struct event_context *, struct aio_event *,
struct event_context *event_context_init(TALLOC_CTX *mem_ctx);
struct event_context *event_context_init_byname(TALLOC_CTX *mem_ctx, const char *name);
const char **event_backend_list(TALLOC_CTX *mem_ctx);
void event_set_default_backend(const char *backend);
struct fd_event *event_add_fd(struct event_context *ev, TALLOC_CTX *mem_ctx,
int fd, uint16_t flags, event_fd_handler_t handler,
@ -79,6 +80,7 @@ struct event_context *event_context_find(TALLOC_CTX *mem_ctx);
/* bits for file descriptor event flags */
#define EVENT_FD_READ 1
#define EVENT_FD_WRITE 2
#define EVENT_FD_AUTOCLOSE 4
#define EVENT_FD_WRITEABLE(fde) \
event_set_fd_flags(fde, event_get_fd_flags(fde) | EVENT_FD_WRITE)

5
source/lib/events/events_aio.c
View File

@ -361,6 +361,11 @@ static int aio_event_fd_destructor(struct fd_event *fde)
epoll_del_event(aio_ev, fde);
if (fde->flags & EVENT_FD_AUTOCLOSE) {
close(fde->fd);
fde->fd = -1;
}
return 0;
}

11
source/lib/events/events_epoll.c
View File

@ -136,7 +136,9 @@ static void epoll_del_event(struct epoll_event_context *epoll_ev, struct fd_even
ZERO_STRUCT(event);
event.events = epoll_map_flags(fde->flags);
event.data.ptr = fde;
epoll_ctl(epoll_ev->epoll_fd, EPOLL_CTL_DEL, fde->fd, &event);
if (epoll_ctl(epoll_ev->epoll_fd, EPOLL_CTL_DEL, fde->fd, &event) != 0) {
DEBUG(0,("epoll_del_event failed! probable early close bug (%s)\n", strerror(errno)));
}
fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT;
}
@ -202,7 +204,7 @@ static void epoll_change_event(struct epoll_event_context *epoll_ev, struct fd_e
static int epoll_event_loop(struct epoll_event_context *epoll_ev, struct timeval *tvalp)
{
int ret, i;
#define MAXEVENTS 8
#define MAXEVENTS 32
struct epoll_event events[MAXEVENTS];
uint32_t destruction_count = ++epoll_ev->destruction_count;
int timeout = -1;
@ -306,6 +308,11 @@ static int epoll_event_fd_destructor(struct fd_event *fde)
epoll_del_event(epoll_ev, fde);
if (fde->flags & EVENT_FD_AUTOCLOSE) {
close(fde->fd);
fde->fd = -1;
}
return 0;
}

5
source/lib/events/events_liboop.c
View File

@ -101,6 +101,11 @@ static int oop_event_fd_destructor(struct fd_event *fde)
if (fde->flags & EVENT_FD_WRITE)
oop->cancel_fd(oop, fde->fd, OOP_WRITE);
if (fde->flags & EVENT_FD_AUTOCLOSE) {
close(fde->fd);
fde->fd = -1;
}
return 0;
}

5
source/lib/events/events_select.c
View File

@ -104,6 +104,11 @@ static int select_event_fd_destructor(struct fd_event *fde)
DLIST_REMOVE(select_ev->fd_events, fde);
select_ev->destruction_count++;
if (fde->flags & EVENT_FD_AUTOCLOSE) {
close(fde->fd);
fde->fd = -1;
}
return 0;
}

17
source/lib/events/events_standard.c
View File

@ -30,7 +30,7 @@
#include "includes.h"
#include "system/filesys.h"
#include "system/select.h" /* needed for WITH_EPOLL */
#include "system/select.h" /* needed for HAVE_EVENTS_EPOLL */
#include "lib/util/dlinklist.h"
#include "lib/events/events.h"
#include "lib/events/events_internal.h"
@ -61,7 +61,7 @@ struct std_event_context {
};
/* use epoll if it is available */
#if WITH_EPOLL
#if HAVE_EVENTS_EPOLL
/*
called when a epoll call fails, and we should fallback
to using select
@ -229,15 +229,15 @@ static int epoll_event_loop(struct std_event_context *std_ev, struct timeval *tv
timeout = ((tvalp->tv_usec+999) / 1000) + (tvalp->tv_sec*1000);
}
if (epoll_ev->ev->num_signal_handlers &&
common_event_check_signal(epoll_ev->ev)) {
if (std_ev->ev->num_signal_handlers &&
common_event_check_signal(std_ev->ev)) {
return 0;
}
ret = epoll_wait(std_ev->epoll_fd, events, MAXEVENTS, timeout);
if (ret == -1 && errno == EINTR && epoll_ev->ev->num_signal_handlers) {
if (common_event_check_signal(epoll_ev->ev)) {
if (ret == -1 && errno == EINTR && std_ev->ev->num_signal_handlers) {
if (common_event_check_signal(std_ev->ev)) {
return 0;
}
}
@ -353,6 +353,11 @@ static int std_event_fd_destructor(struct fd_event *fde)
epoll_del_event(std_ev, fde);
if (fde->flags & EVENT_FD_AUTOCLOSE) {
close(fde->fd);
fde->fd = -1;
}
return 0;
}

11
source/lib/events/libevents.m4 Normal file
View File

@ -0,0 +1,11 @@
EVENTS_OBJ="lib/events/events.o lib/events/events_select.o lib/events/events_signal.o lib/events/events_timed.o lib/events/events_standard.o"
AC_CHECK_HEADERS(sys/epoll.h)
AC_CHECK_FUNCS(epoll_create)
if test x"$ac_cv_header_sys_epoll_h" = x"yes" -a x"$ac_cv_func_epoll_create" = x"yes"; then
EVENTS_OBJ="$EVENTS_OBJ lib/events/events_epoll.o"
AC_DEFINE(HAVE_EVENTS_EPOLL, 1, [Whether epoll available])
fi
AC_SUBST(EVENTS_OBJ)